handbook of textile fibers

Handbook of TEXTILE FIBRES

By J. GORDON COOK

BSc. PKD, CChom. FRSC

II. MAN-MADE FIBRES

W O O D H E A D P U B L I S H I N G L I M I T E D

Cambridge New Delhi

Published by Woodhead Publishing Limited, Abington Hall, Granta Park, Great Abington, Cambridge CB21 6AH, England www.woodheadpublishing.com

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Formerly published by Merrow Publishing Co Ltd First published 1959 Second Edition 1960 Third Edition 1964 Fourth Edition 1968 Reprinted 1974 Fifth Edition 1984 Reprinted 1993, 2001, 2002, 2009

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FOREWORD

The manufacture of textiles is one of the oldest and most important industries of all. Its raw materials are fibres, and the study of textiles therefore begins with an understanding of the fibres from which modern textiles are made.

In this book, an outline is given of the history, production and fundamental properties of important textile fibres in use today. The behaviour of each fibre as it affects the nature of its fabric is discussed.

The book is in two volumes. Volume I deals with the natural fibres on which we depended for our textiles until comparatively recent times. Volume II is concerned with man-made fibres, including rayons and other natural polymer fibres, and the true synthetic fibres which have made such rapid progress in modern times.

The book has been written for all concerned with the textile trade who require a background of information on fibres to help them in their work. Every effort has been made to ensure that the text is accurate and up-to-date. The information on man-made fibres is based on facts supplied by the manufacturers of the fibres themselves.

In writing this book I have been given much encouragement and help by many individuals and organizations. The manufacturers of the man-made fibres mentioned in the text have gone to great trouble on my behalf in providing information and in checking the text before publication. I would like to acknowledge their help, with grateful thanks, and also that given to me by the following individuals and organizations:

D. A. Derrett-Smith, Esq., B.Sc., F.R.I.C., Linen Industry Research Association.

Dr C. H. Fisher, U.S. Dept. of Agriculture. The Cotton Board, Manchester. Stanley B. Hunt, Textile Economics Bureau. Dr R. J. W. Reynolds, I.C.I. Dyestuffs Division. Mr H. Sagar, I.C.I. Dyestuffs Division. H. L. Parsons, Esq., B.Sc., F.R.I.C., Low and Bonar Ltd. L. G. Noon, Esq., Wigglesworth and Co. Ltd.

v

F O R E W O R D

vi J.G.C.

Silk and Rayon Users Association. J. C. Dickinson, Esq., International Wool Secretariat. W. R. Beath, Esq., and his colleagues; Courtaulds Ltd. E. Lord, Esq., B.Sc, Cotton Silk and Man-Made Fibres

Research Association. K. J. Brookfield, Esq., Fibreglass Ltd. F. H. Clayton, Esq., Wm. Frost Ltd. Burlington Industries Inc. J.G.C.

NOTE ON THE FIFTH EDITION

The man-made fibre industry has expanded greatly since the fourth edition of Handbook of Textile Fibres was published. Many new fibres have come into production in countries throughout the world, but the emphasis has been largely on development and modification of established fibre classes, rather than upon the introduction of fibres of new chemical types.

Within almost every chemical class there is now a family of fibres displaying a range of properties and applications limited only by the fundamental chemical structure of the fibre class. To include detailed information about every fibre in production would have meant producing a book of unmanageable and uneconomic size. In this volume, therefore, I have provided background information about each chemical class of fibre, based usually upon a fibre in current production which exemplifies its chemical class. More specific information about individual* fibres will be found in a supplementary volume.

Since the fourth edition was published, production of some classes of fibre has been suspended. I have, however, retained information about these fibre classes; they are of technical and historical interest, and there is always the possibility that production of these fibres may restart to meet changing economic and technical circumstances.

As in previous editions, I have been given much valued assistance by fibre manufacturers and textile organisations throughout the world. Many individuals have gone to great trouble on my behalf by providing information and checking the text before publication. I would like to acknowledge their help with grateful thanks.

CONTENTS

MAN.MADD FII}RES

FuNrolrr4rNr rs. oF FrBnB Srnucrune

A. Nalural Polynrer Fibres

L Cu,lur-ose Flnnr,s; R,r,yoNsViscose RayonCupro (Cupramrnoniunr)Snponi f icd Ccl lu losc Estcr

2. Ce,i-lur-ose Esl:n FlnnnsCellulose Acetate (Acetatc)Cellulose Triacctate (friacetatc)

3. Pnorarx FrnnnsCasein FibresGroundnut Protein FibresZein FibresSoya Bean Protcin FibresCollagen FibresMiscellaneous Protcin Fibrcs

4. MrscrlurNEous NrrrunLr- PolyveRAlginate FibresNatural Rubbcr FibresSil icate FibresSil ica Fibres

B. Syn(hctic Fibrcs

l. Pot-y,ruroe lltnncsNylon 6.6Nylon 6

page

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l 4 l144t46t47

FrnRrs 1 4 81 4 81 5 3t't 61 7 8

t92

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C O N T E N T S

Nylon I INylon 6.10New Types of Polyamide Fibre

2. Polyr,srr,n FlnnesPoiyethylene Terephthalate Fibres

(PET Polyester Fibres)Poly-1, 4-cyclohexylene-dimethylene

Terephthalate Fibres (PCDT polyester Fibres)Other Types of Polyester Fibre

3. Por-yvlNyr" DEnrvrrrvr FlnnnsPolyacrylonitri le FibresPolyvinyl chloride FibresPolyvinylidene chloride FibresPolyvinyl alcohol FibresPolytetrafluoroethylene (and related) FibresPolyvinylidene dinitri le FibresPolystyrene Fibres

4. Polyolerrx FlnRrsPolyethylene FibresPolypropylene Fibres

5. Polyunsnr,q,ne Frnnes

' 6. Mrscnlr"rNe,ous Syvnrr,nc FlnRrs

Glass FibresAluminium sil icate FibresNfetall ic FibresPolyurea FibresPolycarbonate FibresCarbon Fibres

INoex

page2 9 2302308328

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3163 8 8

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5 3 65 4 1564

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INTRODUCTION

FUNDAMENTALS OF FIBRE STRUCTURE

During the last half-century, all the familiar materials that the world has been using for thousands of years have come under the microscope. Science has opened up a great era of exploration which is probing into the nature of material things. We want to know why different forms of matter behave as they d o : and to fina our answers we have had to study the atoms and molecules from which materials are made.

In this respect, natural fibres have proved to be one of the most interesting fields of modern scientific research. As raw materials of one of the world's greatest industries, and as peculiar forms of matter in their own right, fibres have long excited the curiosity of scientists. Now, research into the chemistry and physics of fibres has provided a satisfying explanation of the unusual and invaluable properties that they possess.

Thread-like Molecules All fibres have been found to share one thing in common; the fundamental particles, the molecules, are always long and threadlike. That is to say, the molecules of fibrous matter are in the form of hundreds or even thousands of individual atoms strung together one after the other. The molecule of cellulose, for example, is built up by the plant from hundreds or more of small glucose molecules, each of which in turn contains six carbon atoms. The cellulose molecule, therefore, is in the form of a long thin chain of atoms.

The molecules of a fibre are thus in shape very similar to the fibre itself. And just as the fibre bestows its characteristics on the yarn of which it forms a single strand, so does the fibre derive its properties from the thread-like molecules of the substance from which it is made.

One of the most outstanding properties of a fibre is its strength. Relative to its cross-sectional area, the strength of a silk fibre, for example, is extraordinarily high. A single strand, so fine as to be almost invisible to the naked eye, will support a weight of several

A* ix

I N T R O D U C T I O N

grams. Yet, at the same time, this filament is flexible and resilient. In silk, as in other natural fibres, the thread-like molecules tend

to lie along the direction of the fibre itself; they are aligned in one direction like sticks in a bundle of faggots. It is almost as though the silkworm, in extruding its silk, the sheep in growing its wool fibres, and the plant in producing its cotton and flax could align the long thin molecules as the fibres are formed.

Orientation This orientation of the fibre molecules is not a precise geometrical arrangement. Rather is it a tendency for the majority of the molecules to lie in one direction. The effect on the fibre is analogous to the effect of the individual strands twisted into a rope - each one plays its part in taking up the strain on the rope as a whole.

Long molecules of this sort are a characteristic of the peculiar forms of matter we call plastics and rubbers, as well as fibres. Buv it is only very special types of long molecule that are able to form fibres. They must, for example, be fairly regular in shape with a 'repeating' pattern of atoms in the molecule. They must not have large pendant groups of atoms sticking out from the sides, or the long molecules are unable to pack together.

When the long molecules are able to pack closely together, they can exert strong forces of attraction between each other. In a fibre the molecules are able to develop these forces, and it is this that is responsible for many of the fibre's characteristic properties.

Inside the fibre the long molecules lying alongside each other pack tightly here and there into their little bundles. But the molecules are so long that they can each be involved in many different close-packed bundles. In between these orderly regions, the fibre molecules run through regions in which the molecules are aligned to some degree along the fibre, but are not aligned with the precision that allows them to pack together into well-ordered bundles.

The effect of this wandering of molecules in and out of regions of tight-packing is that each individual molecule is tied firmly to its neighbours at intervals along its length. In between each 'tied' region there is a sector of freedom and disorder. It is this peculiar molecular arrangement that gives a fibre its combination of strength and flexibility.

x


Though nature herself produces many different sorts of long molecules, she has used few for making fibres. The differences between the natural fibres are the result of different characteristics in the constituent molecules.

The long molecules of a typical fibre-forming material are able to pack together closely alongside one another, like sticks in a bundle of faggots. The regularity of structure brought about by this arrangement results in regions of crystallinity in the fibre. These are regions in which a number of molecules are aligned in such a way that strong forces of attraction hold the molecules together. The bonds developed in this way are not chemical bonds in the familiar sense, but they are stronger than the normal forces of attraction exerted between individual molecules.

The degree of order introduced by these regions of crystallinity is an important factor in determining the usefulness of a potential fibre. Individual molecules forming part of a region of crystallinity may wander through a tangled mass of molecules in random arrangement, and then form part of another region of crystallinity. In this way, the molecules forming the fibre are arranged into a structure consisting of regions with a high degree of alignment where the molecules hold tightly to each other, and regions of random arrangement where the molecules are not holding tightly to each other. The crystalline regions provide strength and rigidity, and the amorphous regions provide flexibility and reactivity.

The ratio of crystalline to amorphous material h&s an important influence on the properties of any fibre. In the case of natural fibres, this is an inherent property of the fibre which is fixed by nature. In the case of a man-made fibre, the crystalline-amorphous ratio may be controlled to a large degree by the conditions under which the fibre is produced.

C R Y S T A L L I N I T Y

XI


Cellulose In the vegetable fibres, cellulose is the material that provides the thread-like molecules. This molecule, built up by nature from smaller glucose molecules, is regular in arrangement, but it is fairly rigid in structure. The cellulose fibres, in consequence, are strong and tough.

At regular intervals along the cellulose molecule there are groups of atoms which tend to attract water. When cotton, for example, is steeped in water, these groups encourage the relatively small water molecules to penetrate between the long thin cellulose molecules. As a result, the fibre structure is loosened up and softened. In a humid atmosphere, therefore, cotton fibres are not so inclined to break - a factor that may have helped the growth of the cotton trade in Lancashire.

This softening effect of water also explains how mercerization can give its special properties to a cotton fabric. The effect of the caustic treatment is to force water molecules into the fibre, making it soft and plastic. The cellulose of the cotton is thus able to 'flow' as it is stretched.

Animal fibres are made from proteins, the class of substances used in the animal world for so many building jobs. Protein molecules are, once again, long, thread-like chains of atoms.

In the plant world, cellulose holds a monopoly in fibre production. Whether it is in cotton or the trunk of a tree, in flax or in the fruit or leaves, the cellulose has the same chemical structure. But the proteins used in the animal world differ widely one from another.

Proteins The long molecules of a protein are built up from some twenty or so different types of small amino acid molecule. The proportion and arrangement of these different units determine the structure of the protein molecule and the nature of the protein itself.

By comparison with proteins, the regular cellulose molecule built from its glucose units is simple and straightforward. Protein molecules, with infinite possibilities for the arrangement of their many constituent amino acid units, are exceedingly complex. But chemists have been probing steadily into the mysteries of protein structure during recent years, and we are beginning to understand the intricacies of these complex molecules.

xii


The protein molecules in wool are now regarded as being folded molecules. The long, thread-like chains of atoms do not lie straight alongside each other; they bend backwards and forwards like a meandering stream.

In the ordinary unstretched wool fibre, these folded molecules are arranged alongside each other and lie in the general direction of the fibre itself. When the fibre is stretched, the folds in the molecules are partly straightened out until they cannot unfold any further. The wool fibre is then at the limit of its elasticity.*

Cross-links There is another fundamental difference between the cellulose molecules in cotton and flax, and the protein molecules of wool. Whereas the close-packed cellulose molecules are held together solely by electrostatic forces of attraction, the close-packed wool molecules are actually joined together here and there by chemical links. These 'cross-links' act as extremely strong ties between the molecules. They ensure that when the molecules are stretched out of their normal folded shape, they return to that shape when the stretching force is removed.

One of wool's most important characteristics is its thirst for water. As in the case of cotton, the small water molecules can penetrate between the long wool molecules. Under suitable conditions, wool can absorb half its own weight of water.

Unlike cellulose, however, the protein of wool is attacked fairly readily by water, which causes profound changes in the wool molecule. If wool is stretched, for example, and then heated in boiling water and allowed to cool whilst still stretched, it will remain in its stretched form.

The reason for this is found in the cross-links which join the wool molecules together. Hot water or steam can destroy these links so that the molecules are free to stay in the new positions they reached when the fibre was stretched. Moreover, prolonged heating will actually cause new links to form which anchor the molecules firmly in their new positions.

This is what happens when hair is given a permanent wave. The hair is bent and twisted into its curly shape, which stretches

* Stretching of wool fibres only partly straightens out the folds. Complete transition from a-keratin to /J-keratin only takes place on destroying the cross-links.

xiii


and distorts the fibres. It is then steamed whilst held in this shape: the links between the distorted molecules break down and then rebuild themselves in their new positions. Once this has happened, the hair fibres are fixed firmly in their new shape.

Silk Protein Silk, like wool, is an animal fibre, and it is once again a protein. But the chemical structure of the silk protein is different from that of wool. This difference is reflected in the difference between the two fibres.

Where wool molecules are folded and capable of being stretched out straight, the silk molecules are in the extended position to start with. That is why silk possesses little 'returnable' elasticity after a substantial degree of stretching. When it is stretched with sufficient force, the molecules have to slide over each other and do not return to their original positions when the stretching force is released. The molecules of silk are not joined together by chemical cross-links as are the molecules of wool.

Research has shown that in silk the protein molecules are highly orientated - they lie in the direction of the fibre and can pack tightly together. The forces of attraction between the molecules are thus able to come into play and give the molecular bundles very great strength.

The effect of heat on silk is similar to its effect on wool. At a high temperature, silk will burn. But silk is simpler than wool in its molecular structure. There are no cross-links between the molecules to break down or rebuild. Silk will thus stand higher temperatures than wool without taking any harm.

Sericin, the gum that holds the twin strands of silk together, is a protein similar to that of silk. But the molecules of sericin protein are not aligned, and the material is thus not fibrous.

This difference between silk fibre and sericin gum is an example of the requirements for fibre formation. It is not enough that the molecules of the material should be long and thread-like. To make a useful fibre, they must be of such a shape and structure that they can be aligned and packed together alongside each other.

Effect of Orientation Differences in the properties of natural fibres of similar chemical constitution can be explained in part by variations in the state of

xiv


alignment of the molecules. Flax and cotton, for example, are chemically almost identical; they are both cellulose fibres. But flax has tensile properties quite different from those of cotton; it has a tenacity of up to 55.6 cN/tex (6.3 g.p.d.), compared with 26.5-44 cN/tex (3-5 g.p.d.) of cotton.

These differences in the tensile properties of cotton and flax are caused by differences in the fine structure of the two fibres. Most important of all are the differences in the degree of alignment of the cellulose molecules themselves. In flax, the molecules are highly orientated along the fibre; they lie alongside one another in the same direction as the fibre itself. In cotton, this degree of alignment is not so high; there are more of the molecules lying 'out of true'.

When the flax fibre is subjected to a stretching force, the aligned molecules combine to resist the force. But in cotton, many more of the molecules are lying at an angle to the long fibre axis and contribute little to the strength of the fibre. In natural fibres, the 'degree of orientation' of the long molecules is controlled by nature, and there is little we can do about it. Nature gives flax and ramie their unusually high tensile strengths by aligning their molecules to a high degree. We have no way of increasing the degree of orientation of the cellulose molecules in cotton in order to make it compare in strength with, flax or ramie.*

In natural fibres, also, the way in which the molecules are aligned is complicated by various factors. The cellulose molecules in flax or cotton are organized in unit bundles or fibrils, which are in turn built up into larger units in the fibre. These molecular bundles are not laid down by the plant in a simple fore-and-aft fashion along the fibre; they are in spiral form.

As would be expected, the nature of the spiral in cellulose fibres has a great influence on the tensile properties of the fibre. The greater the angle of the spiral, the more the fibre can stretch before the aligned molecules have to take up the full strain of the tensile force. Cotton, with an angle of spirality of about 31 degrees, has a much greater elongation at break than flax, with its spiral angle of 5 degrees.

The effect' of orientation and spirality can thus be seen quite clearly in the case of natural cellulosic fibres. Cellulose is a reasonably uniform straightforward molecule which consists of

* The degree of orientation of cellulose molecules in cotton can be increased to some extent by mercerization.

XV


COPOLYMERS

( A ) R A N D O M C O P O L Y M E R — X — X — Y — X — Y — Y — Y — X —

(B) B L O C K C O P O L Y M E R — X — X - X — X - X — Y — Y - Y - Y —

(C) A L T E R N A T I N G C O P O L Y M E R — X - Y ~ X - Y - X - Y — X ~ Y -

(D) G R A F T C O P O L Y M E R - X - X - Y — Z - Z — Z - Z - X - Y — o r — X — X — X — X — X — X

I Y I Y I

Y

Linear molecules may be produced by polymerization of a mixture of monomers, forming 'copolymers' in which the linear molecule contains two or more types of monomer unit. A number of different types of copolymer may be produced in this way, as shown above.

In a random copolymer, the monomer units are linked together in random fashion. In a block copolymer, one or more of the components may be polymerized to form sections of molecule containing only one type of monomer unit. These 'blocks' are linked together to form the linear molecule. In an alternating copolymer, the monomer units alternate in sequence along the linear molecule. In a graft copolymer, a block of third component may be grafted on to the linear molecule, forming part of the molecular chain itself, or forming a side chain.

many repeating units of smaller glucose sections. But the proteins from which the animal fibres are made are much more complex in their detailed chemical arrangement. The orientation of protein molecules such as those of wool, for example, is complicated by the existence of chemical bridges between the molecules, and by the folded state in which the molecules lie.

Control of Orientation We can do little to modify the degree of orientation of the molecules in natural fibres. But in making semi-synthetic or synthetic fibres the alignment of long molecules is an essential step in manufacture. We are able to control the alignment in such a way as to exert a major influence on the properties of the fibre itself.

xvi


M A N - M A D E FIBRE Y A R N S

Man-made fibres are made by extrusion of fibre-forming substances in liquid form (molten or in solution) through fine holes in a spinneret. The jets of liquid are hardened in one of several ways to form solid filaments. These are drawn or stretched and may be twisted slightly together to form yarns of virtually any desired length, which are known as continuous filament yarns. The fila

ments may also be collected together into a thick rope or tow and then cut into short lengths to form staple fibre; this may be combed, attenuated and spun into yarns by techniques similar to those used for natural staple fibres such as cotton or wool, forming staple or spun yarns.

Continuous Filament Yarns. These consist of unbroken filaments which are held together into a yarn by a slight twist. They are smooth and generally compact and are used for satins, poults, taffetas, failles and similar fabrics.

Spun or Staple Yarns. These consist of short fibres held together by the twist given to an attenuated strand of fibres. They are generally much fuller in handle than continuous filament yarns. The short fibres lie at various angles with respect to the long axis of the yarn, the degree of uniformity depending upon the combing and other treatments given to the fibre strands before being twisted together. The surface of a spun yarn is rougher to the touch, owing to the fibre-ends protruding from it, and spun yarns are in general fuller and warmer than continuous filament yarns. They are used for sports shirts, suitings, sheets, blankets, furnishing and other fabrics.

The first step in making a synthetic or semi-synthetic fibre is to obtain a substance with the requisite long thread-like molecules. In the case of a synthetic fibre, this substance is built up from simpler chemicals; in the case of a semi-synthetic fibre, such as a rayon, the substance has been made by nature.

xvii


In its 'raw' state, a fibre-forming substance may be little more than an amorphous material such as, for example, the powdered casein from milk, the cellulose of wood pulp or the ribbon of tough horny plastic extruded from the nylon-manufacturing plants.

In this bulk-material, the long thread-like molecules are mixed up one with another in more or less random fashion, like the mass of fibres in a bundle of cotton wool. In order to turn the material into a textile fibre, we have to (a) shape it into the usual fibre form, i.e. a long, uniform rod of extremely fine cross-section, and (b) ensure that the long molecules of the material are aligned so that they tend to lie alongside one another in the same direction as the long axis of the fibre itself.

Spinning The first stage of fibre-production is carried out by rendering the mass of fibre-forming material into a liquid or semi-liquid state. This can be done either by dissolving the material in a solvent, or by heating it until it melts. In either case, the long molecules are freed from close entanglement with each other, and can move independently.

The liquid containing the fibre-forming material is then extruded through very small holes so that it emerges as fine jets of liquid. These jets are hardened, forming a solid rod which possesses all the superficial characteristics of a long filament such as silk.

In the production of man-made fibres, the extrusion of liquid fibre-forming material, followed by hardening of the fine jets to form filaments, is described as 'spinning'. It is similar to the 'spinning' process used by the silkworm or the spider, resulting as it does in the production of continuous filaments.

The hardening of the jets from the spinneret may be carried out in one of several ways:

(1) Wet Spinning. The solution of fibre-forming material may be extruded into an aqueous coagulating bath in which the jets are hardened, as a result of chemical or physical change.

Viscose, for example, is wet spun, th.e solution of cellulose xanthate being extruded into an aqueous solution of acids and salts. Cellulose is regenerated, and this is insoluble in water, forming solid filaments.

xviii


SPINNING

(1)

C O N T I N U O U S F I L A M E N T

Y A R N

S P I N N E R E T (2)

The term 'spinning' is used to describe any process used in producing continuous yarns or threads. Confusion is often caused by the fact that it refers to two different techniques, each of which achieves the above result. 1. In its original textile sense, spinning is the process which has been used for thousands of years for converting a mass of short 'staple* fibre, such as cotton or wool, into continuous yarns. The mass of fibre is drawn out into strands, which may be subjected to combing and other processes, and the attenuated strands are then twisted so that the fibres grip each other to form a 'spun' yarn. 2. In making man-made fibres a liquid fibre-forming material is extruded from holes in a spinneret. The jets of liquid are hardened as they emerge, forming continuous filaments which may be virtually any length. A number of them twisted together form a yarn. This process, too, is called spinning.

Continuous filament yarns 'spun' in this way may be cut into short lengths of staple fibre, and this may then be 'spun' into yarns in the same way as cotton or other staple fibres.

(2) Dry Spinning. The fibre-forming substance may be dissolved in a solvent. As the jets of solution emerge from the spinneret, the solvent is evaporated, e.g. by a stream of hot air, leaving solid filaments. Acetate, for example, is dry spun by extruding acetone solutions of cellulose acetate into hot air.

(3) Melt Spinning. The fibre-forming material may be rendered liquid by heating it until it melts. The molten material is extruded

xix


STRETCHING

( B ) Stretching (drawing) and Alignment. The extrusion of fibre-forming material brings about some slight degree of orientation of the linear molecules in the direction of the fibre axis. This is most pronounced near the outer surface of the filament (the 'skin effect') (A).

The subsequent stretching or drawing of the filament continues the alignment of the molecules throughout the bulk of the filament material. The crystalline regions are orientated in the direction of the fibre long axis, and the molecules in the amorphous region are brought into greater alignment, increasing the degree of crystallinity of the material (B). The properties of the fibre are greatly influenced by the amount of stretch to which the filaments are subjected.

through spinnerets, and the jets harden as they cool on emerging from the spinneret. Nylon and Terylene', for example, are melt spun. Skin Effect The extrusion process brings about some orientation of the long molecules inside the filament. This is especially pronounced on the outer surface of the filament, where the molecules have been influenced by the edges of the spinneret hole.

xx

( A )


It is now established that the surface of an extruded filament is usually more highly orientated than the material inside the filament. This surface alignment is known as the skin effect. It has an important influence on the properties of the fibre.

Stretching Orientation of the long molecules is completed by stretching the filament. This has the effect of pulling the long molecules into alignment along the longitudinal axis of the fibre, so that they are able to lie alongside one another and develop their cohesive forces.

The degree of orientation depends upon the amount of stretch to which the filament is subjected, and by controlling the stretching (or 'drawing') it is possible to control the tensile properties of the filament to a high degree.

In the production of a synthetic fibre, we have control over the chemical nature of the fibre-forming substance, and hence can produce a fibre with well-defined chemical properties and behaviour. This control over the chemical structure of the fibre also enables us to control the shape and the physical behaviour of the long thread-like molecules that we make.

It is reasonable to expect, for example, that slender, uniform molecules will be able to pack alongside one another much more efficiently than irregular molecules with awkward knobs and angles destroying their uniformity. A bundle of bamboo canes, for example, will pack together more tightly than a bundle of twigs.

In making a synthetic fibre, therefore, we tend to design our long-chain molecules in such a way that they have an opportunity of packing together with reasonable efficiency. Large groups of atoms attached to the sides of the long molecules are generally undesirable, for example, as they prevent the close-packing which contributes so greatly to fibre strength. Crystalline and Amorphous Regions Wherever the thread-like molecules are able to pack closely together in a fibre, there is a tendency towards an ordered arrangement of the atoms with respect to one another. These tight-packed bundles of thread-molecules are, in effect, regions of crystallinity; they possess the regular and precise arrangement of atoms that is characteristic of any crystal such as salt or copper sulphate.

xxi


In between these regions of crystallinity are regions in which the molecules have not been able to line themselves up with such precision. These are the amorphous regions of the fibre.

In this modern conception of fibre-structure we regard the long thread-like molecules as passing through regions of ordered crystalline arrangement which are embedded in amorphous material. The molecules in the amorphous regions are aligned to some degree, but have not been lined up with the precision that enables them to pack together in a well-defined crystalline form.

X x - x

- x - x - x - x - x - x - x - - x - x - X - X - X <

(A) x " x " X

- x - x - x - x C , x ^ v

\ (B)

— X - X - X - X - X C ?

- x — x - x - x C

(O x " Cross Linking and Chain Branching. The production of long molecules during polymerization of a monomer X may take place in such a way as to form a linear molecule (A). It may, however, form branched molecules (B), and these may eventually link together to form network structures (C).

The formation of branches tends to reduce the ability of the linear molecules to pack together in such a way as to form regions of crystallinity, and branched molecules do not as a rule result in good fibre properties.

The formation of a network structure, in which the linear molecules are linked together, prevents movement of the chains of atoms relative to one another. Close-packing of the chains is not possible, and crystallization does not normally take place.

Network structures may be created after the linear molecules have been formed and aligned into fibres. This has the result of binding the molecules firmly together, and may.improve certain fibre properties. Swelling may be reduced, for example, as solvents (e.g. water) cannot penetrate so readily between the long molecules. Cellulose molecules are cross-linked in modified rayons such as Topel* and 'CorvaT.

x x i i


During the stretching operation in synthetic fibre manufacture, the long molecules slide over one another as they are pulled into alignment in the direction of the fibre's longitudinal axis. As drawing continues, more and more of the molecules are brought to a state where they can pack alongside one another into crystalline regions; in these regions, the molecules are able to hold tightly together as a result of their cohesive forces. They will then resist further movement with respect to one another.

When nylon is drawn in this way after spinning, a filament may stretch to as much as five times its original length. Then, quite abruptly, the drawn filament will resist further stretching. Its molecules have aligned themselves as effectively as possible into crystalline regions and are holding tightly together. The filament will now withstand much greater force without stretching, and if the load increases it will eventually rupture as the molecules are dragged apart.

Effect on Properties The degree of alignment of fibre molecules affects the properties of a fibre in several ways. The more closely the molecules pack together, the greater is the tenacity of the fibre. This increase in tenacity is accompanied by a decrease m the elongation at break; the molecules are not able to slide over one another as they could before alignment took place.

A high degree of orientation also tends to increase the stiffness or rigidity of the fibre. The molecules no longer have the freedom of movement that they had before alignment.

Water is unable to penetrate between the molecules in a crystalline region of the fibre as readily as it does in the amorphous regions. Increased alignment therefore tends to lower the moisture absorption of the fibre. This resistance to water-penetration affects the dyeing properties in a highly orientated fibre; molecules of dyestuff cannot migrate from the dyebath into the spaces between the fibre molecules.

This resistance to penetration by foreign molecules affects the general chemical stability of a fibre; highly orientated fibres are more resistant to chemical attack.

There is a marked change in the appearance of fibres as they are drawn. In the undrawn state, nylon is usually dull and opaque; as the filaments are drawn, and orientation increases, the fila-

xxiii


merits acquire a transparency and lustre which are characteristic of drawn nylon.

MAN-MADE FIBRES

Though nature has used long thread-like molecules for many purposes, it is only in a relatively few cases that she has fulfilled the requirements for a textile fibre. In wool and cotton, flax and silk, nature has carried out the entire job of fibre production. All we have to do is to avail ourselves of nature's bounty.

In other cases, nature has associated her fibre-forming substance such as cellulose with extraneous materials that make it useless as a fibre. In wood, for example, the cellulose fibres are bound together by lignin and other gummy substances.

Yet again, nature may produce the necessary fibre-forming molecules, but omit to align them in the necessary way. Casein, for example, the protein of milk, will form a fibre if the molecules are arranged alongside each other.

POLYMERIZATION C H 2 = C H C l + C H 2 « C H C l + C H 2 « C H C l

V I N Y L C H L O R I D E

I — C H 2 — C H C l — C H 2 — C H C l — C H 2 - C H C l "

P O L Y V I N Y L C H L O R I D E ( A )

N H 2 ( C H 2 ) 6 N H J H + H O { O C ( C H 2 ) 4 C O O H

D I A M I N E D I B A S I C A C I D

I N H 2 ( C H 2 ) N H . O C ( C H 2 ) C O O H + H 2 0

H [ H N ( C H 2 ) 6 N H . O C ( C H 2 ) 4 C O ] O H + N H 2 o

P O L Y A M I D E

( B )

chemical action which results in the molecule, commonly water. Polyamides polymerization (B).

Polymerization may take place in one or other of two ways: (1) Addition Polymerization.

- This is a process in which monomer molecules link together without the elimination of atoms to form by-product molecules. The monomer molecules literally add together. Polyethylene, polypropylene, and polyvinyl chloride (A) are examples of fibre-forming polymers made by addition polymerization. The monomer molecules link together via the double bond in the molecule. (2) Condensation Polymerization. This is a process in which the linkage of monomer molecules takes place by

elimination of a by-product are produced by condensation

xxiv


xxv

The great modern rayon industries have developed from these natural long-chain molecules which nature has neglected to turn out in the form of ready-made textile fibres. Cellulose from wood is a raw material for rayon; it is separated from its undesirable gums and then re-made into fibres suitable for textiles. Casein from milk, and other proteins, are manipulated until their long molecules are lying side-by-side in fibrous form.

Finally, we have now learned to remain entirely independent of nature for our fibre production. We can start from scratch and actually make the long fibre-forming molecules themselves from simpler chemicals. This is what we have done in making nylon and the other synthetic fibres. As a result, we have opened up a great new field of scientific industry which can provide us with fibres unlike any that we have been able to derive from nature's limited selection of ready-made long-chain molecules.

Classification of Man-Made Fibres Man-made fibres fall naturally into two broad groups, depending on the origin of the fibre-forming materials from which they are produced (see page xxx).

Man-made fibres are considered under two main headings: A. NATURAL POLYMER FIBRES (in which the fibre-forming

material is of natural origin). B. SYNTHETIC FIBRES (in which the fibre-forming material is

made from simpler substances).

These main sections are sub-divided as follows:

Natural Polymer Fibres The fibres in this group may be classified into the following sub-groups: (1) Cellulose Fibres; Rayons (in which the fibre is wholly

or mainly cellulose). (2) Cellulose Ester Fibres. (3) Protein Fibres.

(4) Miscellaneous Natural Polymer Fibres.

Synthetic Fibres Synthetic fibres may be classified with reference to their


chemical structure. The following synthetic materials have become the* basis of commercially-important fibres: (1) Poly amides. (2) Polyesters. (3) Polyvinyl Derivatives.

(a) Polyacrylonitrile. (b) Polyvinyl chloride. (c) Polyvinylidene chloride. id) Polyvinyl alcohol. (e) Polytetrafluoroethylene. if) Polyvinylidene dinitrile. (g) Polystyrene. (h) Miscellaneous Polyvinyl Derivatives.

(4) Polyolefins. (a) Polyethylene. (b) Polypropylene.

(5) Polyurethanes. (6) Miscellaneous Synthetic Fibres.

This is not by any means the only effective way in which man-made fibres may be classified, but it is a simple and straightforward method of considering fibres on the basis of their chemical constitution. It is the classification which has been followed in the remaining section of the Handbook.

It should be remembered that modern synthetic fibres are often copolymers or modifications of polymers, and they may on that account be considered as belonging to two or more chemical subgroups. For the purposes of this book, fibres are included in the sub-group represented by the major constituent of the polymer.

Federal Trade Commission Fibre Identification Act 1958 In recent years, the number of synthetic fibres appearing on the market has given rise to considerable confusion regarding the true nature of textile products. In order to protect producers and consumers from misbranding and false advertising, the U.S. Federal Trade Commission established Rules and Regulations for Fibre Identification which came into force on 3 March 1960. After that date, the following generic names were obligatory for man-made textile fibres:

Acetate (and Triacetate). A manufactured fibre in which the fibre-forming substance is cellulose acetate. Where not less than

xxvi


xxvii

92 per cent of the hydroxyl groups are acetylated, the term 'triacetate' may be used as a generic description of the fibre.

Acrylic. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 85 per cent by weight of acrylonitrile units (—CH2—CH(CN)—).

Anidex. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 50 per cent by weight of one or more esters of a mono-hydric alcohol and acrylic acid (CH 2 = CH-COOH).

Aramid. A manufactured fibre in which the fibre-forming substance is a long chain synthetic poly amide in which at least 85 per cent of the amide linkages ( - C O - N H - ) are attached directly to two aromatic rings.

Azlon. A manufactured fibre in which the fibre-forming substance is composed of any regenerated naturally occurring proteins.

Glass. A manufactured fibre in which the fibre-forming substance is glass.

Metallic. A manufactured fibre composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal.

Modacrylic. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of less than 85 per cent but at least 35 per cent by weight of acrylonitrile units ( - C H 2 - C H ( C N ) - ) , except fibres qualifying under subparagraph (2) of paragraph (j) (rubber) of this section and fibres qualifying under paragraph (q) (glass) of this section.

Novoloid. A manufactured fibre containing at least 85 per cent by weight of a cross-linked novolac.

Nylon. A manufactured fibre in which the fibre-forming substance is a long-chain synthetic polyamide in which less than 85 per cent of the amide ( - C O - N H - ) linkages are attached directly to two aromatic rings.


Nytril. A manufactured fibre containing at least 85 per cent of a long chain polymer of vinylidene dinitrile (—CH2—C(CN)2—) where the vinylidene dinitrile content is no less than every other unit in the polymer chain.

Olefin. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 85 per cent by weight of ethylene, propylene or other olefin units except amorphous (non-crystalline) polyolefins qualifying under category (1) of paragraph (j) (rubber) of Rule 7.

Polyester. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 85 per cent by weight of an ester of a substituted aromatic carboxylic acid, including but not restricted to substituted terephthalate units p ( - R - 0 - C O - C 6 H 4 - C O - 0 - ) and para-substituted hydroxybenzoate units p ( - R - 0 — C 6 H 4 - C O - 0 - ) .

Rayon. A manufactured fibre composed of regenerated cellulose, as well as manufactured fibres composed of regenerated cellulose in which substituents have replaced not more than 15 per cent of the hydrogens of the hydroxyl groups.

Rubber. A manufactured fibre in which the fibre-forming substance is comprised of natural or synthetic rubber, including the following categories:

1. A manufactured fibre in which the fibre-forming substance is a hydrocarbon such as natural rubber, polyisoprene, poly-butadiene, copolymers of dienes and hydrocarbons, or amorphous, (non-crystalline) polyolefins.

2. A manufactured fibre in which the fibre-forming substance is a copolymer of acrylonitrile and a diene (such as butadiene) composed of not more than 50 per cent but at least 10 per cent by weight of acrylonitrile units (—CH2—CH(CN)—).

The term 'lastrile' may be used as a generic description for fibres falling within this category.

3. A manufactured fibre in which the fibre-forming substance is a polychloroprene or a copolymer of chloroprene in which at least 35 per cent by weight of the fibre-forming substance is composed of chloroprene units (—CH 2—C.C1=CH—CH 2—).

xxviii


Saran. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 80 per cent by weight of vinylidene chloride units (—CH2—CC13—).

Spandex. A manufactured fibre in which the fibre-forming substance is a long chain synthetic polymer comprised of at least 85 per cent of a segmented polyurethane.

Vinal. A manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 50 per cent by weight of vinyl alcohol units (—CH2—CH(OH)—) and in which the total of the vinyl alcohol units and any one or more of the various acetal units is at least 85 per cent by weight of the fibre.

Vinyon. A manufactured fibre in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85 per cent by weight of vinyl chloride units (—CK,—CHG1—).

xxix

MAN.MADE FIBRES

A: NATURAL POLYMEIT FIIIRES

B: SYNTHETIC FIBRES

tsrtFlIE

rrlot-(t)U)T'

t i

T : Ir D | - jll a\r ' | Yo z

oH

-l

=z

3I

a@v

*El s= - l o f

e fi{l-s;-1fi-l Heae]

- I

I i = l -

fr-l a=l . Lid I rE;_l F

;=] ;==l == I -

n= L

@ *-u;J

: l l : = 7

-l I gur=l | *ufi=-a | | 4 _ l r F

l ,# l l = li r l r j f iH I F - . l i

r = r

a

,oz

F

- o; =x == zi i r

ao

E <o z! <o -m o

z

> 3

9 <A Z

i l -r m 9= J ks = 4s H A: > cs z o

aJ- a

o

Q <= <- z= <= -

z

{vz

=6

zoca

A: NATURAL POLYMER FIBRES

I. CELLULOSE FII]RES; RAYoNS2. CELLULOSE ESTER FIBRES3. PROTEIN FIBRES4. MISCELLANEOUS NATURAL POLYMER FIBRE.S

INTRODUCTION

ln 1664, the famous Engrish scientist Robert I{ooke pubrisrrcd abook called Micrograp.iia. Amo'gst tt.,"-i.,.,ony subjccts I-lookcdiscusscd. was trrc possibir i ty oI i ' r i tnt ing trrc i i rkwoi ' to iu.r . .a' rrtificial fibrc. I{cre was ar i 'scct th'' i 'racre trrc rin.ri t,ro*nlextile-fi.bre sinrply by forcing a liquicl through a tiny h;lc-;,; i i;hca_d. Why could not we do the iame thir ig rncctr lnical ly, andnrake an art i f ic ial s i lk?It w^s nca'ly two hu'crrccr years bcfore .Llookc's suggcsrio' wasstrcccssfully triecl out. onry the silkworm k'cw how i6 n.,,i[" ii i.l iquid that hardencd into i i lk af ter i t t rao L..n squir tccr i ' to rhcai1. \9!9aV could suggest arrything clse to do thc job.

. In 1842, an Fnglish weaver, LouG Schwabe, dcviscd a nrachincfor making artificial fi larnents by forcing tif,,fa tt.,rough ;;;t;i;;;^oles. The rnaterial he usecr- *os gtnsi,-*lrri.rr wis"su;l;i.;i i;p last ic when molte' to bc.forcecl- t t . , rougtr thc trolcs, 'ar; . i ; ;1

woLrlcl cool to a solid once it cante into "intu"t witlt tlre air.This was thc neares-t thing yet to arr artificial fibrc. Buf'giu*fibre was not suitablc for texliics, nna s"ii*"rre's cntrcatics to trrcscientists to provide something better were of no nvail.At that t ime, science lrad harcl ly bcgun to intcrcst i tscl f i ' thenature of fibrous malerials. The txistencc of long tl r;"l-;;;i;:culcs, such as are neecjed for fibre_forn.,niior.,, had not "u.,r- fr..,,suspccted. But it was realizcd trrat in natural cclrurosc ir,.i"-**a potential raw materiar for nraking fibrcs. Natur" tr.rr"ti ir. '",t.ccllulose fibres in cotton ancl flax. lVhy sirould not nran makcuse o[ lhe vast stores of vcgetablc ccturose ior r,aking racritionalsupplies of textile libres?

I I A N D B O O K O F T E X ' T I L E F I B R E S

Unfor tunatc ly , thc cc l lu losc f ronr wood aud st raw and s int i larsources was associated with gumrny matcrials such as l ignin. Andthough in sonre cases it was possible to separate the fibrouscellulose in useful form - for example, f lax - most of it was uselessfor tcxti le purposcs. What rvas nceded was some way of purifyingthe cellulose and obtainiug it as a satisfactory fibre.

Dur ing the la t ter par t of the n inetecnth cent t t ry , many at tcrnptswcre nrade to use crude cellulose as raw material lor a texti leIibre.

'I 'he problem resolved itself into finding a way of dissolvingcellulose, separating the l iquid from the impurit ies and thensquir t ing i t through t iny holes and hardcning i t in to a f ibre.Ccl lu losc, however, would not d issolve in any sui tablc l iqu id.

Nitroccllulose

In 1846 a scientist trriedrich Schtinbein discovered that ccllulosecould be turned into anothcr substance, nitrocellulose, when itwas treated with nitric acid. This nitrocellulose was a highlyf lamnrable nrater ia l ; i t was, indeed, explos ive. I ts d iscoverynrarked the beginniug of the nrodern explos ives industry ; and,rnixed rvith camphor, it gave us the l irst man-made plastic,ce l lu lo id.

f ?H cHzoH f ?H fH'oHc-c c-o c-c c-o

___.o,/6" AV* t./il \-o.-16H *\,H H.1x \r---H\ /-o-\H H/\ H\ /-o/\u r/.H

c-o c-c c-o c-ct t l t l l

cH2oH H OH CH2OH H OH

CELLULOSE

I NrrnnrroNY

H oNoe fH.ONoa T ONo2 tHzoNo2

_ _ _,.o.../i;[y,' 1z[- oy

-o - j[ut\." r,^rf; -

]\, - - -n\

' ,L-ro,'\lto.T,z"'H "\

- 7L-'o"u19xo.fi\

t o g-9 9-o 9-9cH2oNo2 H oNoz cHzoNo2 H ONOz

CELLULOSE N ITRATE(N TTROCELLULOSE)

A : N A T U R A L P O L Y [ { E R F I I } R E S

Ni t rocc l lu losc, urr l ikc i ts parcnt nratcr ia l cc l l t r losc, d issolvct lrcadi ly ; for exanrplc , i ' a ' r ix turc o[ c thcr a 'c l ' lcorror . r , r iasJ,Gcorge Audemars discoverccl that if hc clippe<l n 'cecllc i;1" ,;so lut io 'o f n i t rocc l ru lose and t t ren drcw i t away, a I i ra l r rcnt wasforrrrcd which dricd a'<r rrarcrened i ' the air anct courd bc rvou'dtup into a reel. The modern rayon inclustry had bcgun.

Whcn cellulose is turncd i irto nitroccilulosc, t ic lrrolcculcsrc.rain i ' thcir long trrrea<I-rike shapc; snrail groups o[ ator's huvcbecn attached to their sides, maiirg thc new substaucc 'rorcsoluble. when Audemars touchecr thc nitroccilulosc rot,,rio,i-,ui,Jthe 'd 'cw h is nccctc away, t r re arco 'or ancr c t r rcr "unpornt . , i i i it 'c. air, Icaving tlrc solicl nitrocellulosc bchi.cl. ,tn.i ttr.

- lo,ig

r 'o lccules wcre ablc to hold lhc n i t roccr lu losc togctr rcr i ' i ts ncrvil Dt'ous sl)ape.' l 'hese ' itrocellulose fibres wcrc a grcat adva'cc r.orvartrs trrcproduction of a comnrercially uscful f i-brc. Thcy ,u".. ,ufi, ; i l ;;and f lex ib le. But thc i r I Iar ' r 'ab i l i ty prcvcrr fcc l - nrry grc^t , , * . u ithc

,f ibres for nraking tcxti lcs - no-uo,ry wantcd [o wcar crotrrcsnraclc f ro ln guncot ton.

.^ l^"_. l f l?1, th i r ty ycars passccl unt i l , in 1g83, Si r Joscgrh Swant)cgan rooKrng ror sorne way of 'ak i .g I i rar 'c . ts for r r i i crcct r icl ight bulbs. He warrtccl sbnrctrring tir irt wourtl givc hir) !;r icxt remely f ine f i lament of carbonf and he uscr l n i t rocc l lu losc.

,Swan .pa.tented a process foruqrirt ing .itroccllulos" ;1,;;;;;through holes to forrn fi la'rcnts,'follorvctl by a chc.ri la i;;; i_nrcnt oI t l re f i lanrents whicrr charrgcd thc < l .ngcrotrs r r i t rocc i lurosc

back in to harmless cc l lu lose.l ' I885, Swan exhib i tec l text i rcs nrade f rom rr is ,ar t i f ic iar s i rk ' ,

^u,:,1 ,]:-l:T

Tlli]ly interestcct in his fitamcnrs as r way or nrlkingnnc carbon nranrents for lanrps, ancl hc fairccr to fojrow up trritextile possibilities.

Clmrdonnet SilkI\'[carrwhile,,in 1878, Count I-li lairc dc Charclortnct bcgarr cxpcri_tncnting i. Fra.ce. crrnrclonnct was a stucrcrrt at trrc i:.ot" ti,i iy-tcc^niquc undcr Louis pastcur at thc t imc of t rrc pdbrir . , . inv.r i i -gat ion i ' the si lk industry. I - Ic becar 'c i rr tcrc.stcd i r i t r rc sirkwor 'r jsabi l i ty^t-o sr i l f ibres, a 'd crctcrnr incct to cr i rurr tc i t ^r t i f ic i l i ry.rn 1884, chardonnct nracle rr is f i rst art i f i l iar f ibrcs from nitro-ccl lulose solut ion which was squir tcd t^rougi i t iny rrorcs, rr ; rrdcnccr

5

I { A N D B O O K O F T E X T I L B F I B R E S

in rvarm air and then treated clrenrically to convert it back tocellulose. Materials made front this arti{ icial silk werc cxhibitedat the Paris Exposition in 1889 and Chardonnet secured financialbacking for the industrial development of his l ibre. A factorywas built in 1890 at Besangon and began producing'Chardonnets i lk ' .

This was the first artif icial f ibre to be produced commercially,and it marked the beginning of our modern man-made fibreindustry. But nitrocellulose is a highly flamnrable material, andthe nranufacturing process proved dificult and dangerous. Largescale production of Chardonnet silk was never realized, althoughthe fibre rvas manufactured sporadically unti l 1949. In that year,the only remaining Chardonnet silk factory, in Brazil, was burneddown.

The Chardonnet process is no longer used commercially. It hadthe advantages of simplicity, a stable spinning solution and aminimum of wastc dur ing manufacturc. l lu t i t was stow inoperation, potentially dangerous and cxpcnsive.

Cupramrttoniunt Fibre; Cupro

In 1890, a new process for making artif icial f ibres was invented,which made use of the discovcry that cellulose could be dissolvedin cuprammonium liquor, The solution was extruded throughsmall holes into a coagulating bath, where the cellulose wasregenerated to form continuous l i laments.

The cuprammonium process was developed into a commerciallyimportant process, and it continues in operation today. Cupram-monium fibre has never achieved really large scale protluction,but the fibre has special qualit ies which have enabled it toestablish important outlets in the texti le trade.

Viscose Fibre

In 1892, another method of making regenerated cellulose l lbrewas cleviscd, in which thc cellulose is converted to cellulosexanthate and dissolved to form the solution known as yiscosc.When fine jets of viscose are extruded into an acid coagulatingbath, cellulose is regenerated in the form of l i laments.

In the years prior to World War I, the viscose libre industrydcvelopcd rapidly, and viscose is now the nrost inrportant rral.uralpolymer l ibre of all.

N A T U R A L P O L Y M E R F I B R E S

Acatotc Fibre

I t rvas not unt i l a f ter worrd war I that anothcr type of ar t i f ic ia lf ibre cane into successfur production. This rvas ,rc fibrc wc ,owknow as acetate.

once again, the raw material is cellulose, which is rcrctcrcclsolub.le by being converted to a derivative, celiulose n..torc, *trj.ndissolves in aceto'e ancl other solvenis. In this ,.rp".t, i t.,"production of acetate resenrbres that of chardo''ct . i i t, wtri.t,was ,nrade by convert ing cel lu lose in to cel lu los. , r i t . i i t " o , ,Jclissolving it in solvent.

cellulose acetate solution is extruded through finc rrorcs, as inthe case of the other regenerated fibres. But in-steacl "i.,rt"ri i ig'*-coagulating bath, the fine jets enrerge into a stream o[ warm irir.-l 'he.solvent

evaporates, leaving fi laments of solicl cellulosc """t"i..The li laments made in this way ctiffer functamenraLlti;;;t i l

rtadc by the c,pramnroniunr or viscose proccsses, in ih^t t l*t ;;;roI rccorvc.tccl to ccilurosc. 1'hcy rcrrrni ' ccilurosc .cctntc, ri, i t ithc propcrties of thc fibre are thus trir lcrcnt frou.r ttror" ot".ttuior.I I DTCS.

Pro!eitt Fibres

ccl lu lose is by far t r rc rnost inrpor tant source of nat . ra l poryr 'crf ibres.made today. But nature prov ic les other rnatcr ia ls which arcca,pable^of fornri 'g f ibres, ancr io're of these rrave lr..n r '0,t. iui.]t lbres o l cotnr t rerc ia l va lue.

._,Protcins., for example,. are usecl by nature in nraking naturalIibres. suc' _as wool, hair ancl silk. "But

th"r. o." nrany ot^crproteins which are not in fibrous fornr, and marry of ttr;r;;;;..be. ,nranipulated to convert them into nU.. r . , t , in thc case ofcclltr lose, it is necessary to dissolve the protei' nna .itr, iJ.-tri.solution in the form of f ine jets which can be frnrd.n.J-inlofi Ianrcnts.

Casein (from milk) , zein, (from maize) and arachin (frontgroundnuts) havc becn made into uscful f ibrcs, but non" fi..,yct achicvcd rtrnjor success in thc tcxti lc f iclcl.

illginate FibrcsAlginic acid extractecr from seawcect is a crre.ricrl rcrativc ofcc l l u l ose ' a .d i t has becou re ' raw n ra t c r i a r [ r o ' r w r r i c r r | i b r cslre spun. Alginate fibres have usefui specialized appticationr, frut

I I A N D B O O K O F T E X T I L B F I B R B S

are of re lat ive ly minor inrpor tance by conrpar isou wi th othcr

natura l polymcr f ibres.

N onrenclatureIn the early days of natural polymer l ibre production, the fibresbecame knorvn as 'artif icial si lk'. The reascitt for this lay in thefact that the fibres were produced in the form o[ continuousfi larnents; in this respect, they resernbled silk rather than theshort staple fibres of cottolt or wool. Also, they often had a silk-l ike sheen.

Ftrndamenla l ly , l rorvever , the f ibres made by the cupram-moniunr and v iscose processes are re lated to cot ton, in that theyarc all cellulose fibres. Silk, on the other hand, is a protein. Thenalnc 'artif icial si lk' was obviously a ntisnomer' therefore,especially as it became apparent that the ne* fibres were estab-lishing thcmselves in their own right in the texti le trade. Theyrvcrc noI nrcre ly subst i tu tcs for s i lk , b t r t had t tn iquc propert ieswhich made thcm unlike any othcr f ibrcs. ln due cotlrse, the term'artif icial silk' was abaudoncd, and the fibres became known asrayon.

At l l rs t , th is terrn inc ludccl natura l poly lncr f ibrcs of a l l types,but it is now restricted to those fibres consisting wholly or sub-stantially of regenerated cellulose. In practice, this means that itrefers to fibres made by the cupranlmoniunr and viscose processes.

Fibres nrade from cellulose acetate are called acela!e (or tri-acetate), and those from proteins are azlorr l ibres. (See U.S.Federal Trade Commission de{init ions on page xxvi).

Nalural Polynrer Fibres TodaY

Viscose, cuprammonium and acetate make up the bt r lk of thenatural polytncr f ibres produced today.

'fhe ccllulosc tlrat scrvesas raw material is availablc in virtually unlimited quantit ies, andthe manufacturing processes have been developed and improvedunt i l thc product ion of natura l polymer f ibres is now one of therlost cfl icient and irnportant industrics in the worlcl.

The rapid rise of the natural polynler l ibre industry is reflected

in thc nranulact t r r ing stat is t ics. At the end of Wor ld War I , the

wor ld output of r t r tura l polyntcr f ibrcs at r lo t t t r ted to-only 9000tonnes ( less than that of s i lk) . I ly 1957 output .had soared tosonre 2tl i uti l l iort totrttes and in 197"1 it was 3'l lnil l ion tortncs.

A : N A T U R A L P O L Y M E R F I B R E S

l. CELLULOSE [tUIlES; RAYONS

I?edcral 1' ratle Conunissiott DelinitiotrTlre ge.neric Lerm rayon was acloptecl by thc U.S. Ircclcral l.racleConr'rission for f ibres of the rcge'ciatccl cellulosc typc, thcoll lcial definit ion being as follows:

Rayon. A manufactured fibre composcd of regcncratcd ccllu_lose, as well as manufacturecl f ibres composecl of rcgencratcclcellulose in which substituents have repracecL.ot more'th;; itp;;ccnt of the hydrogens of the hyclroxyl groups.

This definit ion includes three types of regcreratecr celruloscfibre in production today, i.e. vii iose Rayoir, cuprattrttrottiutritRoyott (Cupro), and Saponiliecl Ccllulose Accrate.

VISCOSB I{AYON

INTRODUCTION

Thc large-_scalc devcloplncrrt of rayon was nrlclc possiblc by C. F.Cross, E. J. I3cvan, and C. Beaclle in Englancl in ig92, whofounclthat they could dissolve cellulose witrrout f irst nrl ir ing it i .ton i t rocel lu lose. The cel lurose was t reated wi th caust ic tJan, t t t .nvrith

. carbon disulphide, ancr the procruct <rissolvccl in cli lutccurstic soda. Tlris viscous l iquid they callecl ,viscosc'.

.. A rnethod of producing texti le l i iaments [ror, t lrc viscosc rvasdiscovered by C. H. Stearn ancl C. F. Tophant, thc l:rtter o[ whonrinvenlecl the 'ageing' of viscose (to i is corrcct conclit ion forspinning), the rnultiple hole spinning jct ancl the fanrous ' l 'oprrarrrspinning box.

. In 1904, the Brit ish rights of trre viscosc process rvcrc purchnscdby courtaulds Ltd., who developccl it into trle most succcssfulnrcthod of rayon nrarru lacture i r r t l rc wor ld.

The viscose process is cornpurativcly lcngthy ancl sonrc 3(X)accuratc ly contro l lcd stcps arc i r rvorvcct . Thc r lw r rntcr ia ls , how-c.vcr' arc chcap. viscosc r.yo' c. ' gc'crally be pro<rtrcccl crrcarrcrthan othcr rayons, ancl viscosc is irow 'ranufacturccl i ' grciitcrqunnt i ty than e i ther cupralnnroni tu l t rayon or ncc l t tc .

I . I A N D B O O K O F T E X T I L E F I R R E S

! :

o :1 tI r .2 : a;t b.i

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t i

g

" . ii ! !: : .. a " l

H i ;y ' ^ i i

' r i

: ;! ;

oo

t! :, aZ Ei :

uz

x ;

; r9 !

;5:: ; :; i !; y 9

o=zz

tszf,

!

of,

zz

U: ;

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A : N A T U N A L P O L Y M E R F I I } R E S

Water is needed i t r grcat quant i ty and utany chcrrr icals arc uscdirr viscose^ rayon rranu.faclure. A kilogra.r oi' ,uyu,, fiti. .rii.ir,tlre use of more than 1,600 kg of watir, nearly i kc of sulDlniiicacid., I ltk^g of caustic..soda., .l.yikg of wood puli o, ;,i i;i l; i;;r,I tg of carbon disulphir te a"nd sr.alrer a 'rou' ts o| otrrer

chernicals.

Conlinuous Filnnrcnt anit SlaplcUntil 1914, viscose rayon was producecl alnrost entircly in thcform of continuous fi la'rcnt yarn. During Worlct War I, 'C;;,rin;and ItaUan firms began proclucing stapl,e rayon fibre by chop_ping the fi larnents after extrusion.'fhe production of rayon staple macle rapid progress duringthe 1930s, and by 1940 there wis as much itaplc bJing used a!continuous fi larnent. After worlcl war rI, f i l irnc.t pio.tr,. i ioi ie-rceeded

lhat of staple u't i l 1954, when siaplc once ;dl, i i ;; i ;thc lcacl. I ' 1961, somc 60 pcr ccnt of thc *orl, l ;;;; i ;,.;;;;consistcd of staplc fibrc.- l ' the 1960s a^d lgzos procluct ion of cor t inuous f ih ' rc ' tdirninished but staple production i,.,rrrrr.J.

TYPES OF VISCOSE RAYON

As co'trol and understancling o[ the viscose process rras irrcrcasctr,i t h .as become possib le to rnodi fy . the propci t ics of t l rc I ibr ; i ; , ;v ' r ie ty of ways. A range o[ v iscose royoni is norv avai lablc whichinclucles fibres of widely dif lering charactcristics.

Physical modificatio's of the viscose fibre ra'gc from crrangcsin thc forrrr of the fi lanrent, e.g. hollow, shapcd nnd surfrric_ntodil ied l i lamcnt (see page 20) io changes i ' irrc l inc structurlcl , r

i ' , t t l " h igh. tenaci ty rayons (sec page 3 i ) ancl h igh wct nroc lu lus(rnc luotng polynosrc) rayor)s (see l lage 47) .

Chemical nrodification, I ikewiscj has rcsultcd in nrany typcs ofnrodificd viscose fibre, such as cross_linkccl, basificd n,iA gi,, itJrayolls (sce page 38).

PI IODUCTION

Il:rrv MutcrinlsThe raw nrater ia ls for making v iscose rayo ' arc c i t r rcr cot to 'l i .ters (the short, useless fibreJin thc co'on boll) or- ivooi;;;

l lI l ' i

I I A N D D O O K O F T E X T I L E F I B R E S

dcrived fronr such tinrber as northern spruce, rvestern lrenrlock,eucalyptus or southern s lash p ine. These pulps conta in about 94per cent cellulose, and are most suitable for f ibre nranufacture.

Wood pulp is puri{ied by boil ing with caustic soda or socliumbisulphite solution. It is bleached and washed, ancl reaches therayon factory in the form of sheets l ike thick blotting paper. Thecellulose pulp is stored under controlled conditions of hurniclityand temperature unt i l the moisture is d is t r ibuted uni formly; th is'conditioning'

nray take several weeks.

Forrtrtt!iott of Alkali Cellulose (Soda Cellulose)The first step in viscose rayon ntanufacture is the production ofalkali ccllulose. The cellulose pulp sheets are steeped in warmcaustic soda for an hour, and then pressed to remove excesssolution. Thc trcated cellulose is brokcn up in a shredder tofornr powdery crurnbs.

The crumbs are aged f<lr up to a day, during which tinrc thccaustic soda reacts with cellulose to form alkali cellulose (socla

oll oHr lC H _ C H

/ \ NaoH- o - c H c H - - - >

\ /a u _ n

IcH2oH

CELLULOSE

OH ONat l

C H _ C H, / \

- o - c H c H *\ /

C H _ OIcH20H

SODA CELLULoSE

tlOH ONa OH OC-SNal t t l

C H - C H C H _ C H/ \ c s , / \- o - c H c H - - o - c l l c H -\ / \ /cH-o cH-ot lcH2oH cH2oH

SODA CELLULOSE SODIUM CELLULOSE XANTHATE

Viscose Rayon. Stage.r itt prodttctiott

t 2

^ : N A T U R A L P O L Y I U E R F I I T R E S

cel lulosc) (scc pagc ^12). ,Dur: ing . t l re agcirrg l )roccss, thc longcellulose morecules are attackci bv- o*-vg"n frorrr rrrc ̂ ir rrrrlbroken up to some extent jnto shorter molccules.

Sodium Cellulosc Xunthute proluctiottThe aged crumbs of -arkar i ceturosc a'c nr ixcrr witrr c.rbo't isulphide in a rcvorving a.r- . i i r" "r 'n"t , wrr i tc crrrrrr t rs rrr . lgradual ly yel low ancl t 'en orn,rg. o, ,oJiu,n . . i i " f"r . _." , i , , , t .is

. formed- (sec pagc l2). The -barcrr

ls t ippccr i rr to :r dirurcsolut ion of caust ic iocra, iormi 'g ; , -hi" [""rangc-browlr sorrr t iorr' fhcre is a roose associat ion ^i t i i i t " r tng" bctwcc. trrc sot l i r rrrcellulose xanthate ancl the ro<.tiui"'i ivr.f ro*j.r..

Thc lustre of thc ray.on is "ont.oit.A-nt ttris stag.. If rlryorr isproduced fronr trrc socr iunr " . [ ; i ; ; ; ; ; ; r rrre sorur io ' wirrrourla^r]ins. anvrhing to . ir, rhe ,ovoii *rii-' i,nu" n sirk_rikc srrccn.o[tcn howcver, a ctulicr appca;;;;;";, prctcrrccl, antt rtris isac' icvccl by adrt i rrg

1l1rc,ylr ' i tc f r isu-. , t , i , r , rr 'y t i r . rr iurrr t l ioxi t lc,to t l rc spinnlng solut ion at this poi i , t i , . , n" i i rulactur.c.Ilipcningfhe sodiurn cel lulose.xanthatc solut iorr (v iscosc solut iorr) isal lowed to sra'<r utra, r ip. i i ' iu;r ;" i ; ' ; ' i 'y ; rr . carc.rry c<.rrr-trolled. rcrrrperarure, crurirrg which'tiirre'ii i i nrt.r.J ;;;;;,i,..r;.sorne breakdown of thc .lJng ".liuror"-"ror*,ii., i,,r"',rri"""iJ;of lower nrolccular wciglr t t iL. . i r i . " . , ' i , i , f r" v i .scosi ty oI t 'csolut ion fal ls in i t ia l lv.orr lurther standi.g, the viscosity of thc sorrr t io ' bcgirs to r iseagain as cellulose is,ie socrium c;ir"r"; fif,:ffi:]:l l'r.llilrofll,1ill ij illlii,jjfor a long tinre, cerurose is cleposit.a rro"ni solution. ln practicc,Iroweve.r, ripening is atow-ccr ,i-t"trir"," 'unrir thc solutio, rrasreachcd a state sui table. for

-sp inni , i r . - ' i

'1 , t^c ' subjcctcd tovacuull l to 'remove bubbrcs of air or-otrrcr gascs wrriclr wourtlin tcr fere wi th tho snrooth f low oC r f , " ,o i " r io , . , dur i r rg s l r i r r r r ing.

Spinning*

T'e r ipencd 'v iscose spinning solut ion is passccr through a r i r ra l* In thc manufaclurc o{ rayon.ancl othcr nrnrr-nradc l ibrcs, lhc tcrnt'sp inning ' has conre to-bc ippi icr i l ; ' t l ; ; 'y , r 'o . . r , o t . forc i r rg t i t l t r idt t r rough t iny l ro lcs,o f?, .1, . , t i ,b nU." . . f :n ; - i l , ; " tcrnr is r rsct l in rhc

if,l,'.,",10?il'i,il:"if.'":"u rttan-t'atlc nu,"i-roi'ii,. rrvisrirrg t.,s.tii.r';i

t3

I I A N D B O O K O F T D X T I L E F I B R B S

fittcring stage, and then forccd through tiny holes bored in a capof metal forming the spinneret. Spinnerets are made from gold,p lat inurr , pal ladium, tanta lutn and other corros ion-res is t ingmetals; platinurn alloys are comuronly used.

The holes in the spinneret are usually between 0.005 and

0.0125 mm diameter, and each spinneret wil l be pierced by upto 20,000 o[ thent.

As it emerges lrom the hole in the spinneret, thc jet of viscoscenters a coagulating bath containing a mixture of acids and salts,typically of the following composition:

Sulphur ic ac id 4-12 par ts by weightSodium sulphate 10-22 parts by weightZinc sulphate l-5 Parts bY weight

In the coagulat ing bath, the sodium cel lu lose xanthate is con-ver ted back in to cc l lu losc. This is insoluble in the l iqr r id o[ thc

bath, so that the fine jet of viscose solution is changed into a soliclf i lament of ce l lu lose.

The action of the spinning bath is complex. 'fhe

sodiumsulphate br ings about the coagulat ion of the sodium cel lu loscxanthate to form a l i lament. This is thcn ccinverted to cellulose

by one or othcr of two routes :(a) thc soclium cellulose xanthate is converted into celltr lose

xanthic acid, which decomposes into cellulose.(b) the sodirrm cellulose xanthate is converted first irrto zinc

cellulose xanthatc, which is then converted into cellulose xanthicacid and finally into cellulose.

The conversion of zinc cellulose xanthate into cellulose xanthicacid takes place more slowly than the conversion of sodiumcellulose xanthate into cellulose xanthic acid, and route (b) isslower than route (a).

In the coagulat ion of v iscose, us ing a bath as out l ined abovc,the z inc sulphate is in low concentrat ion, and i t penetrates onlya short distance into the l i lament in the time that the acid pene-

trates into the centre of the fi lament. The bulk of the fi lament,inclucling, the core, is thus regenerated via the direct route (a).

Only the outer layer is regenerated via the slower route (b).

The slower regeneration taking place in the outer layer of thefi lament results in a nrore uniforrrr deposition of cellulose, andcreates the skin cffect that is typical of a regular viscose fibre.

t4

A T I . ' R A L P O L Y M E R F T D R I ] S

As the core shr inks, thc sk in bcco' rcs wr ink lcc l and thc f i lnrncntacquires its lobed cross-scction.

. ln the product ion of h igh- tcnaci ty f ibrcs of a l l_sk in construc_tion (sec page 43), regc'cration rttardants arc acldccr to thccoagulating bath, slowing up the regencration or cclrurosc bvthe acid, a'd so allowi'g thc srowei route (b) to bri 'g-aLoirircgeneration throughout the .l ibre. This cltcci

' i , int.r.,.r incJ

-tiv

us ing a h ighcr co.ccrr t rat ior r 'o f z inc sar ts in r t , . , t r i , r , . , i , ie- [ , , i i i .I 'he slower rege'cration obtainccr in trris way ailows ti irc forstretching and orientation to be carriccl out morc eflccrivclv.

There are three ways in rvrrich the firanrents are trcatcd aftcrIeaving the coagulat ing bath; the proccsses arc known n, pof o ibox, sp inning, bobbin spinning ani cont in t ious spinning, * rp. . -t i v c l y .

Pot Spinning; I lox Spint ingIn pot sp i .n ing the bunch of f i rarnents f rom cach spinrrcrct is lc t lout of rhe barh and arou'cr a wrrccr. 'r'his whcer - "irr"J rli. e"i[iwhecl - pulls the fi lame-nt rrom the jct at a co'trotcrr spcccr. It isth is speed, together wi th the rate of ext rus ion, which crctcrr ' incsthe d iameter of the rayon I ibre. fhe faster i t is pul led " . i t i . " " . ,the je t , the th inner the f ibre wi l l be.

.on leaving the gocret whccl, the fibrcs pass arouncr a sccorrcrwheel which is movi.g fastcr than thc l irst. -fhe fibrcs arc thcrc_fore stretched bctween trre two wtreers-l-a proccss whicrr has aprofound elTect on the finar f ibre. This stictching or trr" siit i-p last ic rayon tends to or ientate th; nr ; i ; " ; , | "s of cc l lu losc a longthe direction of trre l ibre. rhe tirng nrot.ctires arc po.t". n.,oiit ightly together so that rheir nrutuit oti in"i ion "",":;-i;,r; ; i ;y.Ihey hold strongly to each other, giving a sirongcr tibrc.

. The more. the rayo' is strctcirJd *i., i t" it is sti l l p!.stic, thcstronger is t l re f ibre. I lu t at . thc sanre t inre, t l r is t ig f r t pn" f l , ig 'o i

t 'e molecules recluces..the ,stretchabii iat; 'of t^c fibrc, so thntexcessive

-stretching w'r. achicve high strcngtrr usua'y rrt i i i"cxpense of other desirabre propertics. 1'he treatrrent is trrcrcforcrcgulated to suit ilre co^dirloni tn" nu." *iit r.,"u" to ,riinrinn,i. After stretching, the fibre p_asses into a Tophal' box. This is :ihol lowcontainer i6out rB.*?7i; i i l r Jir] , i"t* rvrr icrr wrrirrs r ikc

I 5

I I A N D B O O K O F T E X T I L E F I B R E S

a sp.inning top. The fi lanrent is lccl through a hole in thc top o[the box a 'd is f lung against the s ide by centr i fugal force. In th isrvay it. is pulled continuously through the hole ancl buil<Is upi'to a cake of f i lament inside the box. A n'rcchanical deviceensures that the cake js built up evenly from top to bottom, anclthe spin o[ the b_ox gives a twist to tl ie f ibres, irsually about L.iturns to the cm (3 turns to the inch) .' lhe

Topharn box rotates some 10,000 tinres per nrinute. Thesides are perforated, so that most of the l iquid i i ftung off fromthc wet f ibrc cake. Up to 63 rn (70 yr t ) a tn inute are fec l in tothe box; i t takes several hours to bui la up a contp lete,cake, ,which is t l 'ren washed and may be treated wittr soaium sulphiclesol.t ion to renrove residual sulphur conrpouncrs. The fibre isbleachcd, .Lrsually with sodiurn or calciirm hypochlorite orperoxide, rinscd in dilute acid, washecl and driecl.

Bobbin Spinning

In bobbin spinning, the fi lanrents of rayon emerging front lhccoagulat ing bath may be wound wi thout twist on to bobbins. Thcbobbins, whicl 'r have perforatecl barrels, are purif iecl ancl bleachecltunder pressure. The yarn is then dried and oiled, ancl after trvist-ing is wound up again ready for winding into skeins or cones.

C o rr! i rttro us S pi nni ngIn the pot and bobbin spinning processes, packages of v iscoscfi lan.rent are collected 1nd then subjected- to desurphurizing,bleaching, washing and drying before tire rayon is ready for usJ.Thc process is thus an interrnittent one, in which batches of I i la-ment are handled separately as they become available.

lJatch processes of this type are inevitably costly in labour aucloperat i .g charges, and the in termi t tent operat ing- tends to in t ro-duce var iat ions in the quar i ty of the prodt ic t f roni batch to batch.I ' .modern industry therc is a te'dincy to favour processes inrvhich the procluct nloves from one stagc to the 'cit in a con-t i .uous st rean.r . cont i r ruous processes of t r r is sor t are usuai lycheapcr to operatc, and can be contro l lec l to proc l r rce a h ighl iruni forrn product .

I t has long been real izer l that the pror luct ion of v iscose rayoncould. be aclapted to operate on a continuous basis. nut ,"nnfpractical problcms hacl to be sorvecr belorc contintror-rs spirrrirribccame a reality. The main difi iculty lay in the time requirecl foi

t 6

A : N A T U R A L P O L Y M E R F I N R E , Sptrr i f icat ion' brcachirrg, waslr ing and crryi 'g of t rrc f i rarrrcrt a[ tcrlcaving rhc coacurar ing br, t t , . l i ' i i , " pr i , i , ' " , iorr of rayorr by potspi'ning, for eiar'plc] ,il;

'; i";;, i j j.,, rakc J0 rrri 'rrrcs orrnore to complete. Ancr. in trr is t i lne, *o. i 'urnn a rnirc of f i ranrcntnr ight be spun' I f cont inuously-pr; ; ; I i ra 'rc ' t took rhc sanrct i 'e to process,, n.-,,1:,1,-li:i i i;,i; ';;;i l; arr cr d rying cq u iprrcn rwould havc lo accon)n_todatc a conrparablc lcngth o[ f i ln lrrcnt.The successfur crevcronrr."t oi;;1;ii;;us spirrning of viscoscwas nrade possibrc to.a rargc cxteni bt ' l ;* dcsig' o[ rrrccrranic.rdcviccs wrrich courcr rtora lnrm"u;; i;r;,ir- o[ firarncnr i ' co'-tinuous movement as they p"rr.,r jfrr*:,il l ,n. o.o..rsirrg train.

Ittdttstrial Rayott Corporatiotr proce.rs

.?:,:lg the 1930s, many firnrs expcrinrcntecl with corrrinuousvrscose spinning tcchniques. onc of t l r"-n"t t" ^" i l ; ; ; . . ; ; , , , :r rrcrcial succcss wns i l . l ) t .occss t lcvclopcr l by l rrr l r rs lr i r r l l t r ryorr

3|'i3:ilt!;|r.u't'n., wtii.l' ",,n,"-inio''or,..",io' nr l.irrcsvlc,T^c probrcrn of harrclr i r rg great rcngths o[ f i r rr . rcrr t rrur i rrgprocessing was solvecl ty.",,ii,rf- rir..?,.r' aovil'c*g rccls ofingenious design. Each recl ""*irt.i""i"o pri,. of rorcrs rvitrraxes set on thc skew, i.e. n_ot parallcl io caclr othcr. Whcrrf i lanrent is fed to one

.end "f " ; ; ; ; " ; i n. ,ouing rol lcrs of t^ issort , a 'd passcd rounrl thc .o 'eis--as' t t rougl, rouncl n pl i r o[pulleys, rhe fitanrent rcrcts to f"r;; ;"rl;;;;l which nrovcs .torrcthe pair of roters unri l . i t . .n"n", i i .*oi i , . . . .a. r . rrc cr i rccr ion ornrovement of the sniral , . the . istancc t . i* . .n thc coi ls, arcl thclcngth of filanrent "u.ii.,l, J;;;;; trJ,, ,,," anglc o[ skcwbctwecn the axes o[ t t re two rol lcrs.A pair of skew_set rollers "un if,i,, bc rrsccl for carryirrg grcatlengt 's of f i lanrent in a.vcry .snral l space, wit l rout p^ysic^l colr l i lctbetween indivicrual coits. df ni;,;;;;-i;i i,,g pr,,"". r'<livictuatstrands of f i lament "^n. b. : , , , f r j " . i .J- ro 'pro""r . ing l iquids ant lcnviron're'ts irr a most dircct

'*^r,-f, c,ontra.t with flla.lentsrvh ic 'a re wou '< I tocc thcr i r r to a c i ( . o r o thcr ' : rckage. . l . l r i s , i r r

l,Ill: i:d":.s rhc piocl:sring ti,n"'-n..i..i'io. r^c trc*tr'crrr o[con t i nuously-prod uced^ fi ln nri. r, o, "oi"pn r.a wi r h t d; -ir;;..r_r

*of - f i larncnt in package tornt .ln the Industr ia l Rayon Corporal ion cont inuous spi r r r r ing pro-cess, the thread advancing rec ls 'conr i r i " ip . i rc o[ skcw_sct hol low

t 7

f__ | l _ - . 1 L I L f

I { A N D B O O K O F T E X T I L E F I B R E S

rollers wlrich rotate one inside the other. A sttccession of thcse

reels carries the fi lament from the coagulating bath and stretching

equipment, through desulphurizing, blcaching, rvashing, oil ing and

cliying stages, unti l eventually a clean, d-ry l i larnent is delivered

,..ua' for -shipm"nt

to the texti le manufacturer. The techrriqtre

has now been devcloped and refined, and Industrial Rayon

corporat ion cont inuous spinning nrachines .are iu widesprcad use

throughout the worlcl. Worlcl rights to the process, cxcluding

U.S.A-. ancl Scuth America, are held by Coultaulds Ltd', U'K'A motlern continuous spinning machine of this type is 6 .rl 'r

(20 f0 high, and has threi operating levels. On the top are the

coagrr ia t ing bath and thc st retching t t rechanisnr , f ro l r t which the

fi larirent moves clownward to pass throtrgh a train of ten process-

ing stages. Each stage consists of a thread advancing reel, and

cltir ing its passage through the reel the fi lament is subjected to

the appropiiate processitrg l iquids or environments. Finally, the

ti lanrcnt passcs through a drying rccl ctrclosccl iu n hclrtctl

chamber. Thc dry fi lament emergcs lront this rccl ancl is twistcd

ontl woutrd on to bobbins which iarry up to 4.54 kg ( I 0 lb)'

The dofl ing of the bobbins is automatic, and there is no intcr-

ru l t t ion to t l ie operat ion of the machine. The ent i rc process is

cont inuous, thc f i lantent bc ing wound on to the bobbin l i t t le more

than 5 minutes af tcr being produced in the coagulat ing bath '

Nelson Process

A cont inuous spinning process was devised in the U'K ' by S ' W'

Barber ancl J. Nelson during the early 1930s. By 1934, the process

was in operation. It has since been developed by Lustrafi l Ltd',

and has bcconre known as the Nelson Process.In the Nelson Process, a combination of two techniqtres is

usecl to overcome the problem of carrying great lengtlrs of f i la-

rncnt during the processiug stages. Firstly, skew-sct rollers areused to carry thc f i lameut , as in the Industr ia l Rayon Process;seconclly, the stages in processing are redttced, desulphurizingand b leaching bc ing ont i t ted.

The thread advancing device, in the Nclson Process, is sinri lar

in pr inc ip le to that used in the Industr ia l Rayon Process, - t r t t tcl iff irs in the details of its operation. The two rollers, instcacl of

rotating insicle one another, are arranged one above the other

l 8

A i N A T T J R A L I ' O L Y [ { D I I F I I T I T E S

l i kc t hc ro l l c r s i n a w r i ngc r , w i t h t hc i r a . r cs . sc [ on thc skc rv . ' t ' hcro l lers, at l 'u t I nr (3.3 f t ) lo .g, carry u lore t r ra ' 100 c. i rs or 't l re f i larncnt s l r i ra l as i t rnovcs f rom onc cncl to thc othcr .

As thc f i lamcnts err iergc f rorn the coagulat ing bath, thcy arccarried upwards to pass over thc uppcr roilcr and tl ic. , iorun-rvards to pass u.der the lowcr ro l lcr , ancl so o ' . ' l 'hc f i rs t co i lsof the spi ra l arc sprayed wi th uc icr , and corgur i r t io^ is corr r -p lc tcd dur ing th is f i rs t s tagc. ' l -hc

f i lanrcnt is thcrr rv .shccl bvwater sprays as i t ' rovcs a lorrg t l r .e ro l lcrs , passi 'g I i 'a l ly ovcr thceud sect ions of the ro l lers, rvh ich are hcatcd. ory t i larncnt t t . , iu .the ro l lcrs , havi 'g spcnt somc 3 nr inutcs t ravcrs i i rg f ro ' r onc c. t lto thc othcr , nrov ing rhrough r ,orc t r ra ' 100 coi - is of t l rc sp i r r lo '_ the way. 1 'hc dry f i larncnts arc t rv is tccr antr co l lcctcd o i r tobobbins, usual ly by a cap spinning mcchanism.

Despi te lhe onr iss io 'of the dcsurphur iz ing sr .xgc, f i r . r 'c . tsproduced by the Nclson Process conta in only b. I _-0: j pcr ccntsrr lp l r r r r . I f , as is r rsr rn l , thc y^rn srr t rscqtrcrr t Iy p l rsscs i r r i .u i ,g l i , ,rvcI proccssi r rg t rcut ' rc ' t , suc l r as scorr r . i r rg o i t iyc i r rg, t l r is s i r r ' l lprop.or t ion of su lphur is rcnrovcd. r f thc subscquci i t t ra ' . t t in !of the yarn docs not inc luc lc a wct proccssing

'opcrat in , r , i t r i

t r : rce of su lph.u. r .nray bc rcrnovccl casi iy by ,v . ih ing thc f r ibr ic .r r rc use ot r r igr r qul r i ty wood purp r ras rc .dcrcd t r rc brcaching

slage unnccessary for most appl icat ions, but b lcacl r ing can n ls ibe carriecl out if nccessary af fabric stage.

Anrcricatt Visco.rc Corporotiotr Itroccs.rTf i is is a ] ' igh-spccd co. t inuotrs spi 'n ing l ) roccss i . rvr r icr r t r rcf i lanrcnts lcavc the coagur ' t ing u i r t r v i i a jc t o f "ong, , iur i i i fl iqu id, in .which the l i laurents ' 'ove for a d is t .nce oI aE. t r t l ic ' r (6. i r r ) . I r i lar 'cnts ther pass round the rcc ls of a thrcaJ-advancrng nrccha' isr 'a t sucl r a spccd that cxccss l iqu i t l is r l r rorvrro(r by centr i fugal forcc. coagtr la t ion of the cc l lu losc co ' t i r r t rcsas thc f i larnents t ravc l a long thc i r sp i ra l path, , , , r , t , t r " t " i r i , , f i ,carr ied out when lcss t r rat 70 pcr ccnt icgc.cr- . t ior r l r : rs r i rkcrrp lacc.

K uljian Proccss

In th is process ' f i la ' rcnts are carr icd f ronr thc coagrrrat i rg b l t r rby godct wheels, ancr prss on to a systenr of roflcis *t, i" i l .. i ibe contro l led to apply a < lcs i rcc l <Icgrec of s t rc tch. - I 'hc

f i larncntsare t rcated as they t ravc l t l t rough t l rc ro l lcr systcnr , arrc l lhcrr

l )

I I A N D B O O K O F T E X T I L E F I D R E S

dr ied by hot a i r . The dry f i laments are wound on to bobbins bya r ing spinning ntec l tat t isnr .

Koltortr 'Okortratic' Process

A process of continuous spinning devised by Von Kohornlnternational Corporatiotr, known as the 'Okomatic' Process,carries the yarn forward by means of a system of skew-set glass

ro l lers.The product ion of yarns by these cont inuous spinning pro-

cesses has now beconre establislred practice in the rayon industry.The quality of the yarns is fully equal to that of yarns producedby batch techniques, and the uniformity of the l i lan.rents is high.TIris increased uniformity is reflected in the reductior"r ofbreakages during weaving, and consequent in-rprovement in thequal i ty of thc fabr ics.

NtoDtrlc^'f loN oF ITILANIEN T

l ly nranipulat ion and modi f icat ion of the spinniug process 'physicrl structure and form of the rayon li lament can

changed in nrany waYs.

Cross-Sectiotr

The cross-sectional shape of the fi lament may be varied by

extruding through spinneret holes of suitable shapc. Modification

of f i lanrent cross-section is becoming of increasing in'rportance

today, as it can cause profound changes in the characteristics of

yarns'and fabrics. Circular cross-section fi laments, for example,

or" poot., in covering power than lobed cross-sections typical

of the normal viscose fi lament. Many synthetic f ibres are now

being produced in non-circular forms, such as dog-bone and

tri lobal cross-sections.Viscose rayon has been made exper inrenta l ly in a var iety of

cross-scctionol Sltu1r.s, and sonrc lrirve become of conrnrercial

importance. Straw fi laments, for example, are produced by.sonre

ntanufacturers. Flat f i laments are made by extrusion of viscos:

tlrrough slit orif ices insteacl of circular ones; these {' i lamcnts havc

improved covering power, but tend to be of harsh handle'

ihc cliarncter o[ a fi lanrc.t ntay be varied continuously betrveen

th ick arrc l th in, prov i t l ing rayon f i lanrcnts whic l t r l lake up in lo

spccial cffcct fabrics.

20

A : N A T U R A L P O L Y M E R F I I } R D S

I) t t b ble-fi I I cd F i I artr c: n t.r' l-he

covering powcr of viscosc firanrcnts rrray bc irrcrcascrl bvspinning in such a way that bubblcs or . i . ' " ; - " l i ; ; ; ; ; ' " ; itrapped inside the firamcnr. This may bc dorrc try rpi, i, i i i ,g"ov iscose solut io ' which r ras bcc. agi ra iccr to producc ̂ [or r ' i r rwhich air bubbles are entrappecl .hr 1976 courtaulds Ltd nraricetccr a rrollow visc.sc tibrc .Vilot.t,

x!i.I is r'ade bv.gc'crari'g carbo' aiu*ia. i,,iia. iii. iir,,,;i;;,i.r r lc 'Dre l l i ls [ reai lv i r rcrcascd bulk a 'd h igh r r ro is turc 'bs. r .pt ior r .

,']:.,9;r:" ur wil' ptityest., ii rrr.r,

"ii' ; ";?,1., i'c rcasc d c.vc ri' g

-. l l le 'ds oI hol low viscose witrr cotton arc uscd irr shir t i 'gs a'c ldrcss fabrics a'd for tcrry t.wel pile. Iloli.w ;ir;.;;; ';ft;;;";widely used in nor-wove's, particulirly l ' fieids ;i;;;;;;;.;ia.d rnedical fabr ics wrrere high rnoistrr ic r ibsorpt io ' a.d ,r , isturchold i rrg p roperl ics arc inrport"ant.l ) rrr i r rg worl t l w'r i l , a bubbrc-r i i lct l v iscosc r i l r rrrrcrrr crr i lcd' l lubblcl i l ' was producccl in.U.S.A. by clu 'c l rr t , usi ,g a tcchrr i r lucby.which. air , rvas injccter l into the i i l "nr. , r t .s i t was cxtrudcd.-fhis produccd a co' t i 'uous f i ranrc' t corrt i i , r ing ai t . r . t" i r i , i l i . ,3-6 "r l*

-% i . ) lo 'g, which was usccl as a subst i tute t i , , k; ; ; ;kirr l i te jackets, por i toorr i , insulatecl ctottr i i ,g etc.

Spturclyed Filatnent and StapleConlrol of the spinning process in rayon procluct ion cnnblcs thc'ranuf lacturer to mix l i r rcry-cr ispcrsccr-pigr i rc ' ts rv i t rr t rrc viscoscsolut ion bcfore spinning. Thc

- pignrcntJ aic loct<c, l i , r* i , | . r l icf i lar,ents a-[ ter spinning' provicl i r r ! 'spuir-Jy.a' r i ra 'rc ' ts rvhiclrarc unusual ly fast to r ight n.cr to w.shing. wrr i tc t i t ln i t , , r . , aiui i , l .is uscd i' this way for duili 'g ttt. n"fJini srrcc' of r^yor.

Crittrp- fhc^spinni rg

qLra l i t ies of s taplc f i t r re arc ustr : r l ly c . l * r r rccd i Ithe f ibre has a wavi .ess or cr inrp 1c i . woory, an. f i ranrcnts rv^ ic l r. re ro bc nradc in to staprc arc co ' r rnonry ' r rcarcd to prov i t rc ac.ritnp.. ' l 'his rnay bc donc rncchlrrically, for exunrl., le by passirrg

t'c f i lar.cnt bctwee' g^car_likc rollcrs,'or cl.,.,r., ic.i ly b; ;";;r,.;tl iug. the coag' la t ion o i thc f i ra 'c ' r i t t - ; , ' ; i ; a way .s ro crc i r tca fibre of asymnrctr.ical cross-scction.

thebe

2t


Chcnrical crimp has resulted very largely from experimentalwork carriccl out in Japan, aud much of the viscose staplepro<lucccl in Japan is now crinrped in tlr is way. The crimp isint roduccd by spinning v iscose into a coagulat ing bath conta in ingless acid and nrore salt than is usual, followed by carefully con-trollcd strctclt ing. The fi lanrent is then ctrt ' into staple and dried.

Filarnents produced in this way have an asymmetrical cross-section, cne side bcing thick-skinned and almost smooth, theother side being thin-skinnecl and highly serrated. When the fibrcsare wet, thcy srvell much more on the thin-skinncd side than onthe thick-skinned side, so that there is a tendency to curl.

A sirnilar efl 'cct nray be introduced into rayon by using the'bicornpcnent' tcchnique which has becn developed successfullyin the plcduction of some synthetic l ibres (see 'Orlon' Bicom-porrcnt Fibrc). This consists in the extrusion of twin fi larnentsthrough orif ices set sicle by side, in such a way that the two{ l l lmcnts jo in ns they coagtr la tc . The cornposi te f i la lncnt is t l radcfrom viscosc solutions of dil lercnt characteristics, atrd the twoportions o[ the fi lament have different swell ing properties. Inwater , thc f i lament tends to cur l as one s ide swel ls more than theo t hc r .

' fhe antount o[ cr imp that is put in to a f ibre depends upon t l te

deci tex. F ibres of 1.7 dtex (1.5 den) may have 5 cr imps percrnand 3.3 dtex (3 den) f ibres 3 cr imps per cm. I f l lbres are-g iventoo nruch cr imp, neps tnay be caused dur ing processing; i f theyarc g iven too l i t t le cr inrp, t l te col tes iot t dur ing processing may betoo low.

Crimped Viscose Rayon. DY suit-able control of spinning condit ions,viscose f i larnents may be spun inwhich the skin is thicker on oneside of the f i lament than ort thcother. Tbe swell ing and othcrcharacteristics of the two sides o[the fibre are different, and the rvetf i lament contracts more on one sidcthan on thc othcr. This produces acrirnp (cf. the relat ionship betwecnthe twirr-corc structure of the woolf ibrc cot(cx and the crir t tp o[ rvool)- Alter Cottlartlds L!d.

22

fiffi*o

r L - * J [ * . , J

A : N A T U R A L P O L Y M E R F T S R E S

Surlace-Modifiect Fibrel-hc nature of the fibre surface influcnccs lhc proccssing pro-perties of a fibre, and .arTects i,r u"i ir"i"rr lr.t ,sc. 'rrrc

stri irte.surface o[,a regular viscose nU.., *i i i i irs typical lobcd cross-scction, influences the sp.innabll it 'y oi""ir.osc staple, a,d alsoirf lects.the appearanc-e and hancte or uir.or" yarus. o. trrc othcrhand, indentat ions of t r r is sor t t * , i - to ' " i ing to par t icrcs of d i r t .and f ibrcs of th is typc arc of tcn more r l i f i icu l t to c lc ln thnnsirnilar f ibres with a non_serratecl surface.. ,

The.unique propcr t ies of wool " r " -J i , . i r r sor .c r r rcusurc tothe scaly surface of th-e fibrc ona nt,, i iy nii inrp,, havc bccn r'adcto create a sur face of . th is typc o ' .ovr i -^nt r othcr nran-nradcfibres' such fibres wourd rr. .^p..t.a^tl i.oui.r" iruproved brcndswi th wool .Surface moclif ied rayon fibres have bccn proclucccl by nrcansof f in ish ing t reatmcnt i , ancl by ur ing u iLrnf ing spinncrc ls .

Il igh l 'cn:rcl{y l lnyolDuring the extrusion ancl strctching which fornr parl. of thcprocess of .producing

. .ny9n f i lament{ thc nro leculer . " i . . f f r f " . r .arc alig'ed and oricntal"cr to- sonrc ,r"gr.. wlrcrc r'orcctrrcs arcable to pack togcther..in orclc.rly i"rfrion,'tr.,.y forrn rcgions ofcrystall inity, or crystail i tcs, wrrich ur"r.pn.nr.,r frorn o.e arol'crby-regions of amorphous cel lu lose.In this respect, the rayon fi lamc't resertrblcs the cotton fibrc,rvhich also consists of cerrulose -"r.*i.r ' parry in crystntine

li1 lirrty in arnorp.trous form. Brt il;; <lirlcrs from corronrn -r n.urnbcr of significant ways.uunng vlscose manufacture, the cellulose nrolcculcs trndergoso.r'e degradation, ana, i ' a norrnal "i;;;r; f ibrc tlrc nrolcculcs

:111j^:.?:Il pcrhaps.20G-700 glucose u"l;. ;;, couon, rtre ccllulose

;il[:",.r are much longer, and may contain 2,000_1b,000 ;ii;;;;;

.^ The prop.ortion of crystatine rnaterial in a nornrar viscosc Iibrets conrnronly in the re-gion of 25_30 p.. "*t, whcrcas in cortoni t is as h igh as 70-75 .per cent . The crysta l l i tcs in rayon t rcstnal ler than in cot ton; in rayon, r f r .y- , , r . , 'o , , tvcragc, about 100tngstroms long and 40 angstronr , * id . ; i i r cot ton thcy l re sonrc199 : :Fstroms. long ancl - 60 n, rgr t io i . r " ' * t0 . . Ntorcovcr rhcorrcnrat io . of t r rc crvst^ l r i tcs nto, [ r t r " nbrc ax is is gr .carcr incot ton than in rayon.


These factors all contribute to the difiercnces in physical pro-perties between rayon and cottotr. In particular, they explain therelative weakness of rayon, especially when wet. And they havepointed the way towards the development of viscose rayous o[increased st rength and d inrensional s tabi l i ty .

'I 'he success achieved in this field is demonstrated by the intro-

duction of high-tenacity viscosc fibres (see page 39). Since WorldWar I I , the usc of h igh-st rength rayon in tyres, conveyor bel t ing,transnrission belting, hose pipes, etc., has become cornmonplace.These yarns are produced by applying a high degree of stretchclur ing manufacture, when thc indiv idual f i lan. rents are in apseudo-plastic state.

' lhe stretching is eflected by suitable choice

and contro l o f the chemicals in the spinning solut ion and in thesp inn ing ba th .

The acicl bath coagulates the cellulose xanthate solution anclpcrmi ts s t rc tch to be appl icd in one or n lore stages. ' I 'hc processruscd in the product ion of 'Tcnasco' yr rns by Mcssrs. Courtaulc lsLtd. is of th is type, prov id ing yarus which are three t imes asstrong as nornra l v iscose rayon.

The acldit ional stretch given to viscose fi laments in producinghigh tenaci ty rayons increases the dcgree of a l ignnrent of thecellulose molecules. This has the effect of increasing the propor-t ion of crysta l l ine mater ia l , and or icntates the molecules andcrysta l l i tes nrore h ighly in the d i rect ion of the f ibre ax is . Thephysical structure of the fibre changes, resulting in increasedstrcngth and d imin ishcd cxtensib i l i ty .

Skin ElJect

When v iscose solut ion is ext ruc led in to the coagulat ing bath, askin of cellulose forms on thc outside of the fi lanient. As coagttla-t ion cont inues, the core of the f i lament hardens and shr inks,causing a wr ink l ing of the outcr sk in of the f i lamcnt . The rcsul tof this can be seen in the serrated cross-section of the norrnalv iscosc f i lanrent . The sk in i tse l f can be d is t inguished by exanr in i r rga dycd and leachcd f ibre. ' I 'he core dyes more readi ly than theskin, and i t l ikewise loses i ts dye more readi ly on leaching, leavinga darkcr shade which can be secn quite easily through the nticro-scope.

Thc sk in ant l corc arc both cc l lu lose, but they d i f lcr in thenature and or icntat ion of thc crysta l l i tes. In thc sk in, thecrysta l l i tes are smal lcr than in the core, and the molcculcs in

N A T U R A L P O L Y M E R I T I B t ( E S

thc -arnorp 'ous rcgions of thc sk in arc rcss r i r 'grcd arrd l r *phaz- l 'd'r arrar)gement than_ in rhc core. .t-hc

skiri is ai;,;, ; i ..;;;;.uniform structure, and the o.i.niotion'oi ,tr. "ryr,,r ' i tcs is ' igrrcrin the sk in than in the core.In the product ion of h igh_tcnaci ty rayor)s, thc congulnt ion anclslretching of the fibre arc controllea in suctr a way Ji; i;;;;#;tlre internar structure of the l iranre"t. ' :rrt ir is acconrparricd by .rrircrcasc in rne propor.rion of ,kii;; ;;;j ;;;; 't,i '] i l;,;;;it io 'of core, to the poi ' t at wrr ichirr . .or i . (rsar)pcars coruprctcly.'fhe.

fibre is coagulared i" " ,r-;;' i;"i;;;"., way, an<I rtrc cross-section beconrcs lcss scrralccl as thc corc_shrinkagc ellcct isdinrinisrrcd' In trre case oI a 'wt.,ot.-s[ini {ib." sr.r, as .' l-errasco

Suder 105', the cross section is alnrost circular.l 'he increased unilormity nri,r orr.,rt,,i ion or thc nrorccurcs irran all-skin fibre of . this iype ;.;;l; ';,; '"n ircrease irr rensites t rengt ' ' I f the nrorccurcs- . ln n n r , in - . . i i t a rc ,o t ' r ig r rca nr r t ll , r"u: : ] . poor rrcgrcc or or icntr i i io i i , " "r" i r t rrc or icrrr^t io ' ̂r r t lcrystallirrity vary grcatly

_throug'oui ti,. i itrr., t,c rcsistn'cc toa te.si le srress wi l t be iakcn b;; ; iy ' ; -r ;"al t proporr ion of rhcavai lable moleculcs at a. t ime. r f , in" i f . " i , strctclrcd, thcsenrotecutes will break, anci orhers *iii ' i";i; up ttrc strain. f.hcsctoo will break, ancl so on.l f the degree of or icnlat ion of the nrolcculcs arrd crystal l i tcsis high, ancl the structure of the nbr. is-rinifornt, a grcatcr pro-portion of nrorecules wi' co-operai" i" i"r.irg trrc strai. rvrrc, trrelibre is pulrccf. 'rrre

fibre *irii"i;;-;';;; ', ' i l. rcrsirc srr'rgrrr.

IIigh lVet Morlultrs Royons; polytrosic Fibrcs (sec pagc 47)I\' lany new types of ui::-:r_: l]"y..cnrcrgccl cturing rcccnt ycars, nstcxt i le scient ists have increascd trreir inacrstandirrg ancr controrof spin'ing ancr proccssing t"Jrriiqi,.r."anron, trrc nrost inrpor-tant are the hieh wet modulus rnodal ancl polynosic f ibrcs.T'ese rrave been -creverop.a

i,i u uu,ri'rrJiir J,ru n trics ; i rr ll ri rair. arrr.odal.fi bre is r'anuftrciu p.a ̂ t y c"" rir,irar'r-ta. u,der Irrc'arirc'Vincel'; in thc U.S.. rn.ocr..r fi6res *.'r"rir.rrr. as ,Avrir' (Avtcxt"i bers I nc.) an d'M ov*cr' (c* iirrri; r'i;;iil'i,;,;;i.n'iui.;)" ""^

Modal arrd polv.osic' f ibres -

are"i i igi, . t . , ,r. i ty, ' ig, wcrrr,dulus rayo's in wrricrr rrrocri{1".t i"" oi ' i l , . , , , , , t . .rr.r strrrcturchas rcsulted in a fibre wirh nranv "iijr;';;;;."rivc crraracrcris(ics

25

. F N F F F F F N F F F T F T E T N FT I A N D B O O K O F T I ] X T I L E F I B R E S

of cot ton. The h igh st rength, espccia l ly when wet , rcsul ts in good

dir rensional s tabi l i ty and f i rmuess.

S(aplc

The nranu[acttrrc of viscose staple l ibre has assttrned increasinginrpor tancc s ince the end of Wor ld War l l . 'Staple is nrac le bychopping fi lanrents, which may havc been crimped nre^chanicallypr c lenr ica l ly , in to shor t uni for tu le t tgths, cotnt t tonly 3B-200ntrn(lth-8 in),

-after they etnerge lrom tl 're coagu.lating.bath. The

i taple f ibr i is then washed and dr ied, and packed in bales.in proclucing staple, it is not l lecessary to control the trniformity

of the fibre to sttch a fine clegree as in the case of continuousf i larnent proc luct ion. (Uni forrn i ty is never theless very good, andi r r t r ins ica l ly bet ter than tbat obta ined wi th natura l f ibres.) Also 'the f i laments cat t bc spun l rom spint tercts wl t ich prov ide a th ick

ropc or tow consist ing o[ thousands of f i laments. These twofactors tencl to lower thc cost o[ producing staplc as conrlrarcdwi th cont inuous f i la tnent yarns.

Viscosc staple nray be b lendcd wi th wool , cot to l l or otherfibrcs, and spun into yarn by the various systenrs trsed for staplef ibres. Yarns tuade f rom v iscose staple are natura l ly f t r l ler and

roughcr in hancl lc that t thosc tuade f rotn f i lamcnt yarns (c f . wool

and s i lk) .

Totv !o Top Conversiotr- I 'hc convers ion of s ta l l le f ibre to yarn involvcs the real ignnrentof thc nrass of short f ibres which have resultccl frorn thc ctrtt ing

oI the fi lanretrts, bringing thcm back, in elTect, towards the state

of a l ignmcnt that they had when they were in the form of uncut

tow. I -n ordcr to avoic l an apparcnt ly u l l l lcccssary d isorganizat ionancl rcalignrnent, tow to top conversiotr techniqucs have been

developecl in which the fi laments in thc tow are cut or broken

into staple and draf ted in to s l ivcr as a cont inuot ls process '

" I ' ( t tusco ' . Opposi tc : l ' l igh tcnnci ty v iscosc rayol ls of thc " l 'cnnsco' . typcarc uroc luccd'bv cr t rus ion of the v iscose into an ac ic l bat l t conta in i r rgz.in.'atr, l socliuni sulphates, follorved by stretching of t lre ne_rvly-fortlrcdf i lanrcnts in hot nqucous ac id. This rcsul ts in increascd molecularor i . i i t i t ion, ancl an ' i t rcrease in the proport ion of 'sk in ' to 'core ' '-

yn i i t n toac in th is w: Iy are st ro l lger t l rnn t tornra l v iscose, and th is"r , t in . t t r . r rgt t r is : rch icvc<i wi th only s l ight _ret luct ion i r r extension atLie:rk.' l ' lr is"nteans that the fibres hlvc n high rvork oI ruptute'-AllerCourtaulds Ltd,

1l) 27

N A T U I I A L P O L Y M E , I T F T B R [ , S

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I I N D B O O K O F ' I ' I ] X T I L E , F I I } R E S

PROCISSING

Desizilg

v iscose. f i lanrent yar .s are conrnro ' ly s ized wi t r r water-solublesizes which arc renroved by scouri 'g. stapre yarns sizecl wiflrs tarch nray be desized by t reatnrent wi t l , " , l "vn l . r .

Scour ing

As in a l l rvet proccssing of v iscose, grcat care must be taken toavoid causi r rg d is tor t ion oJ the rayon goocis when wet . S.oui in lrn i ry bc carr icc l or t rs ing t r re usra l tcchrr ic lucs ror ce l ru los ic nui . . isuch as soap arc l socr iur ' cr r rbonate; so i ip , sr r r fac" act ive ag"r i iand. t r isodiurr r phosphate; soap, sur face act ive agent u, . ,a t . i ra-:::!,: iT

pyrophosphate. Scouririg should be foilowld frv tf,o-ugflnns l l l g .

I l lcnching

Strong. ox id iz ing agents should be avoidecl . B leaching may becarr icd out rv i th hydrogen. peroxic le at tentpcratures up to 50"C. ,ncutra l

-sodiunr l rypochlor i te , .pcrborate, a ic l potassi t ,u . , p . . ,n^ i r_ganatc fo l lorvecl by sodiunr b isu lnhi tc .

Dycing

viscose rayon is a regeneratecr ceilulose fibre, a'cl as such ische ' r i ca l l y a ln ros t i de ' t i ca l w i t h co t t o . . r t ca 'bc < ryec r w i t r r a r tcot ton dyestuf fs , but techniques of c lye ing are i r r i luen".A Uyspccia l f ac l .ors.

Rayon has a greater af r in i ty for dyes than has cot ton. Afr i ' i tvrnay vary according to nranufactur ing concl i t ions, an<J wi l l no ineccssarily be icle't ical irr rayons proclucecl fronr tire ,n,r.,. ptont.. I layon swel ls to a greater extent than cot ton when i t isi lrnrersed in water. The fibres are weakenecl, ancl yarns or fabricsmust be handled wi th great care in the dyebath.

Viscosc is dycd in the fornr of hanks, s iaple f ibre, p icce goodsand 'cake' ( i .e . as col lectec l on the spinning nrachi r ie j . . fhe"h igt idegree of swetling can carse dilf icult ies *Ir"n ,nyon is clyed inpackaged form. Cakes for dyeing shoulc l have an open wind.

I i DACTIVE DyDSTUt ;FS wh ich chen r i ca l l y bond to t heccl lu losc rnolcculcs are of ten usccl .

2829

I

Dr tacr co . r .oN t

NAT. ' l t ^L PoI -YMl lR F IB l t , . s

;:::,TiJix i:, J,',':H'ii,lli:iili) rc rv i'�rc I v I r'� r'� r'� ..'� r v o t I rc r

r ̂src o"n.,unilr tll';iii:: Tillrl",.::,' ::; "':,

:tunobtainable wirh othcr ay*irnr ' i r r . , t i r" f rgi t iu. to l ight.. 'sr,Lpru* Dy[s]'ut;Irs are trsccr rvlrcrr c,rccrcrrt wasrrirr'g f.rt,,..,;:'fii?:Jll ii'JJ;;; ji;;,;'r'o

- -,'tii'et, ..r..c or r,istrrcss lo

:.,.J..11i{1'":1,',,',iifJ'nil,:iT,iJ"';,:[..u,.1,'.,. trvcs arc rror orrc'appriccr to conri, iuorrs riranrc.r i;;;k; ;;fJlu ?:l if." '

brack isSraplc fibrc is dyc<l *itf, n .,,,.rg."oi Jr"i,u,.r,,. clycstulls.^zolc Dycsrunn".,-y1r::rc rayon has a high ,t.gi.e of aflinity forazoic clyesttrlTs (higlrer. tt.run ni.il.i i l..i "otto,,l. .l.hc

colouri arc:ll l; 'H;,'i i l ' l. ltavc

goocl fasttrcss i" ir"tr' i,u, cross-trycirrl;, r.ubbirrg

. v^'r' Dyns'uFF' ilrc lrrc _fastcst of all lrrc crycstu,.s trscrr o.; i :f[ ' : i ::;,1*: rcsist the .n..t, ui ' i igrrr a.rr rvasrrirrg jusr :rs. ,

1-he appl icat ion of vaI c lycs to v jsco.sc r ithc scnsir ivity or rlrc,fi bre., llayo' ;;ii; ;,1v,?* ii ffi?i:'::lfil.,liltuscd irr clyci'g rvirh rhcsc ,ly.riJji, ,,".'i",r1i. bsorbed .'noi. ru 1,i.r y th.r,i l;;

";,; ;;:' ;; ::i;;,:gifiJiii:l:tr.l;

iil il;",f "9il.J',]:il','j' #'lX.; "' t a v.'- *l t r' n;;i-,.;, i ; " i*iiir,iiSptttr-dygd RayonIvluch rayon is norvcolourecl pig.rcnts ,,r"1'f.-o!l1"tt l

i t l the sptttt-dyccl. forrtt, in rv6iclri t " i ; ; ; i ' ; , ; i ; i i : t

tncorporatcd c l t r r i r rg s l i r r r t i r tg . ' r r i ; t p t , " . - t

gc'e rar iy ;i ;;; ;; ;]'i;,,111i":,11:i'.1,,,'.xi1"'.,,,,[. - o i' :; il;.;

Drl,ing

\Vc t v iscdsc nr t rs t bc c l r i c< l in s t rc l t a w; ly as,,,' eccssa ry s t ra i ns ",,"],1: i*.j;l'iil;i i":i,i:,;l l;i,' ",i,,ii,J r. ilil

;,1^jilt widrh rrray bc fo.ilorvctl try ,t;i;;; ';Icsloon drying nray also n a src, r c r .q,, itp..r i,T, inJl'i",',1::li #'^iii ili,ll.''i, li lii, iii

,,.fJ/::.'.. drying stroul<t t," """irJii, as rhis nrly crusc n hnrslr

I H I T F T F F F T I I F I T T FI I A N D B O O K O F ' T E , X T I I - E F I B R E , S

li inishing

The f in ish ing of v iscosc fabr ics is concer t red largely wi th

r ' i . in t iz i 'g t lc shor tcorr ings inhcrcut i r t v iscose, r to tably i ts

scnsi t iv i ty to lvater ' l lcs in f in ishes of Inany typcs are. now .used. f t . . t iu . ty for th is purpose, prov ic l ing increasecl d inrensional

stabi l i ty i t r r ing wasl r i ig , inrproved wr ink le . res is tance aud crcase

rcsistarice. These finishes shorrld be used wit5 cirre, as they rlray

cause loss of abraSion res iStance and tcar s t rength, and produce

a harsh, boardY handle.v iscose fabr ics ntay bc calendercc l caref t r l ly to increase - the

fu l lness of handle. dccat is ing is usecl to produce a wool- l ike

f in ish.

Mercerizittg

Rayon is a lust rous f ibre, and therc is rare ly any cal l for lust re

to Lc incrcasecl , e .g. by ruct 'ccr iz ing. I t nray be dcsi rable, how-

evcr , for b lent ls of cot ton arrd rayon to be t t tcrcct izcc l to imlr rovc

the ius(re of t l re cot ton, ancl br ing i ts dyeing qual i t ies more in to

l i ne w i t h t hose o f t he raYon .Viscose f ibre wi l t wi thstancl thc caust ic soda sol t r t ion uscd in

nrcrccr iz i r r g , but c l is in tegrntes c l t t r ing subseqtrcut rvashing. Specia l

tcchrr iques arc usccl to ovcrcot l lc th is problcm, iuc luding the t tsc

oI caui t ic potash, or nr ix tures o[ caust ic potash aud caust ic socla,

in p lace o[ caust ic soda.

S ' f l {UCI 'U l { I l n ND PI {OPI IR ' f lES ( l {cgu la r V iscose)

l i iue Slructurc ltnd APPcarancc

fhe f i larnent of v iscose rayon is sn looth and st ra ight . I t n tay bc

cr inrped ( 'sar i l le ' ) but there are uo couvolut ions as in cot tot t .

T le sur fa ie is however, marked by longi tudinal chanrre ls which

are causecl by contract ion in volunre of the f i lar lent c lur i r lg

coagulat ion, ' l - -hese channcls or s t r ia t io t ts g ivc the cLoss-sect ion o[

v isc-os" rayon a charactcr is t ic out l ine, rv l t ich is deeply serrated.

Whcn rayon has beetr dul led wi th t i tan ium diox ide, or 'sput l -

dycd ' c lur ing nranufacturc, the par t ic les of p ignlent are scet l as

dark specks embedded in the f i larnent .As iayon is a ma.rr facturcd ntater ia l , t5e c l ia ' reter of t ;e

f i lanrcnt can be var ied through widc l inr i ts . v iscosc is conrnronly

J U J I

A : NA . tURAL t , o r -YM[ , t t

r r r adc i n a rangc o f d t cx . ' l ' yp i ca l s t l n l c

. 5 . 0 , g . 0 r 1 7 , 4 0 , 5 6 ( l k , 3 - , ' 4 k , g , \ 5 ,

ler rgt l rs 32-200 nrrn ( l /a-8 in) .

l 'cnsilc Strength

I r l u t t E s

I ' ibrc d tcx1 8 , 4 4 , 5 0

arc 1 .7 , . 1 . -1 ,c l c r r ) ; s t l r p l c

O, rd i r ra ry v iscose rayor r hus a tc ru rc i ty o l ' lg -23 cN/ tex (z . tJ *2 .6g /dcr r ) d ry ; 9 .0 - 13 .2 cN/ tcx ( 1 .0_ 1 .5 g / t l c r r ) wcr . . l .eDs i l cstrengt lr o[-rrorr 'a l v iscose r 'yo. is 210942i4 kg/c.r2 (30,000 -46 ,000 lb / in2) .

I i lougalion

Nornta l v iscose wi l l s t retch by about l7*25 pcr ccntIength bcfore brcaking, ancl 23-32 pcr ccrit rvlrcrr

IJlaslic l lccovcry

cot tou and other natura l cc l lu losc f ibrcs htvc l i t t lc i 'hcrcntc las t i c i t y ' v i scosc r ^yo , , l r o r vcvc r , h . s cvc ' l css . r t I r . s i r sa r i r i lc las l ic s t rc tch oI about 2 1rcr ccrr t f 'o . r rvr r ich i t rv i l l r jcc.u. . r iwhcn re laxccl . I lu t . rore pcrs is tc ' t s t rc tching wi l l tcnd to carrscPernratrcnt dcfornrat ion as thc long cc l lu losc r r rc l lcculcs s l idc < lvcr .onc ano the r .

Elast ic rccovery (60 per ccnt r .h . ) :I pc r cc r r t cx t cns ion : 67 pc r2 pcr ccnt cxtcnsion: 60 pcr3 pe r cen t cx t c r r s i on : 3g nc r5 1>c r ccn t cx l c r r s i on : 32 j r c r

l0 l ter ccnt cxtcnsion: 2J ncr

cc l l t

c cn tccn tccl ' l tc cn t

Averngc Sti l lncss9 8 c N / t e x ( l l . l g / d e n ) .

In i t i x l M( )du lus

477 cN/ tex (54 g /dcn) .

lYork Factor

0.62.

Spccif ic Grnvity

1 .50 to 1 .52 .

I I A N D I } O O K O F T E X T I L E F I D R E S

ElIcct of I l lois(urc

ln natura l ce l lu losc f ibres such as cot to l l , the cel lu lose molcculesale packed toget l ter in order ly las l t ion wherever a l ignment o[the nro lecules nrzrkes th is possib le. These ordcred, crysta l l inercgions confer s t rength and r ig id i ty on the f ibre; the amorphousregions, on the other hand, wl tere cel lu lose molect l le s arearranged in raudorn fashion are respousib le for the f lex ib i l i ty ,'s t lc tchabi l i ty ' and srvel l ing propert ics of the f ibre.

Wheu naturat cc l lu lose f ibrcs arc d issolvcd dul ing v iscoscrnanufacture, the molecules are set f rce f rout ot te another , andare able to nrove around nrore or less independent ly in the l iqu id.- fhe

cxt rus ion of thc l iqu id, fo l lowccl by coagulat io t r and st rc tch-ing, tcnds to rcstore the a l ignnrent of the cc l lu lose tnolccules andeucourages the fornrat ion of crysta l l ine regious again. ln gcueral ,however, the molecular l inc- t rp is uot restored to such a h ighclcgrcc as in the or ig inal natura l s tatc . Al t l tough the f i larnent o[v iscosc rayon consists of cc l lu losc, i t d i { [crs in th is rcspccL f rot t tcot ton. l t . bchaves in mauy ways l ikc a cot ton in rvh ich thecel lu lose molccules have been shor tencd ( i .e . by chenr ica l act iondur ing r ipcning and ageing) and a l igned wi th rather less prec is ionthan in cot ton. Thc actual dcgree o[ a l ignnrent and crysta l l in i tyclepcncls upon the att.toutrt of stretch that is given to the fi lamentdur ing rnanufacture.

l 'he rcduced crysta l l in i ty of the cc i lu lose i t r v iscose rayotrrenclcrs the f ibre rnore respol ts ive to water-petret t 'a t ion. ' fhenrolccules of watcr can force thei r way bctrvecn the looselyorganized cel lu lose molccules in the antorphous rcgions of therayon. Viscose rayon rv i l l absorb twice as t t tuch rvater natura l lyf ronr thc a i r as cot ton docs. Viscose l tas a nto is ture rcgain o[l3 pcr cent uncler s tandart l condi t ious. (Water inrb ib i t ion: 100-110 per cent . ) When soaked in wi t ter , v iscose rayotr wi l l i t rcreasein lcngth by 3-5 per cent and swel l to double i ts or ig inal vo luure.

This incrcascd watcr penetrat ion is ref lected in the change intcnsi lc s t rengt l t rvhen rayotr is wet ted. Viscose loses as much ashal I i ts s t rengt l t whct t rvct , and is more easi ly s t retched. Thcstrcngth returr ts on dry ing, incrcnsing as the rayot l bccomesbonc-dry.'I 'hcrntnl Propcrties

Ii{Ject ol II iglt ' I 'cntpuature

l layon is not thcrntoplast ic , a t rd c locs not nrc l t or becontc tacky

5 L 3 l

r--T

A : N A l ' U I { A L P O I - Y M I ] I { I : I N I I N S

o . ' e a t i n g . l t b e g i ' s t o l o s e s t r c n g t ' a t l 5 O o c . a [ t e r ' r < l r o r r g c t l'eat i 'g , and beglrs to c leconrpos. i t tgs_zo5oC. (c lcp l i r , i i l " ; ; ,t inre factor) .

Flatnrrnbility

Rayon burns rcacl i ly wi th a charactcr is t ic oc lour of brr rut p lpcr .

l i l tcct ot Agc

So s l ight as to be a lmost n i l .

I i l lcct of SunligtrtV iscose rayon wi thsta 'ds cxposurc to su ' r ig ' t wi t 'out r i iscolora-ll?it:, l l :.t^":pcd

expo^surc causcs a grartual loss o[ rcnsilc srrcngrtr.r r l ls ls l l )orc sevcre i f thc f ibre coni r ins t i tan iurn ox ide.Chcrnical Propcrlie.s

Acids

Sinr i lar [o cot ton. v iscosc rayon is at tackccr by r rot d i rutc or cc l l t lcorce ' t ratcc l r . ' inerar ac icrs, wrr ich weak*r arr r r d is i r r tcg ' r tc t l rcf ibre.

Alkolis

L ikc cot ton, v iscosc rayon r ras a h ig ' crcgrcc oI rcs is t . .cc t .d i lLr te a lka l is . Stron ' ! so iut ions of ^rka ' r i - c i i rsc srvc ' i .g , wi t r r r .ssof tcnsi le s t rcngth.

G etteral'I 'he

cellulose of viscosc rayon u'crcrgoes sor.rc aclrory'rcrizatio,dur ing the r ranufactur i 'g proccrr . r ' i r ; - ; ; ; " rc f lcrs to c^cr ' icarsi r a ' ra. 'er s i ' r i rar to cot ion, r rut i t g1n.*ry r 'orc scnsi t ive. l tis attackcd bv oxidizirrg agcnrs such as rrigh-strerietri- i,;, ir"g.l,pcrox idc, but . wi l l wi thstancl nornra l l iy foct r tor i tc or pcroxidcblcaches.

Mlcct of (Jrganic Solvcrrtsv iscose rayo ' is insoluble in most organic solvcrr ts ; i t a issorvcs i 'a fcw co'rplcx solutions, s.uc' as c,,, lr..nrr'o,ri,,,rr: D;t-; l;;;,;;so lvcnts do not havc any c lc lc tcr ious^cf lc f i .

I I A N D I ] O O K O I - T E X T I L E F I D R g S

Lr.sccls

Viscosc is res is tant to insect at tack but is at tacked by s i lver- f ish.

M icro- organisnrs

Nlilclews do not reacli ly attack the cellulose of the nbre itself, but

wil i feed on the size that is left on the fibres after processing'

Milclervs wil l cause discoloration, and weaken the l ibre if the

at tack is severc.

Mcctrical I 'ropcr(ies

Thc h igh moisture absorpt ion of rayon tends to detract f rom i ts

value f or insulat ion purposes ' Thc d ie lect r ic s t rength of dry

fabrics is fair. Undei orclinary conditions, viscose rayon does

i rot c lcvelop stat ic charges but ant is tat ic agents are usual ly addcd

i f the re lat ive humidi ty is less than about 30 per cetr t '

TENACITY

l o 2 0 3 0 . 4 0srRArN (2 e loNcnrtoruT

N A T U I { A L I ' O L Y N , l I ] I I I . I D I T ! , S

IN USEVISCOSE RAYON

In the man-rnadc f ibre f ierd, rayon prays a ro lc s inr i rar to t r rnt oIcot ton in the f ie ld of natura l f ibrcs. I t is produccd i , , gr ln t . ,quant i ty t 'an any other nran_r ' ,oa, nUr. ; " i t ' is re la i ive ly ; i l ; ;and has a wic le range of oppt i .n i i r i r . " ' ' - '

A l though v iscose rayon is s imi lar to cot ton in i ts cc l ru los icstructure, it provides a range of yarns ancl fabrics wltf i tf,. lr o*ncharacteristic propertics. Tlie cclrulosc oi ioyon has bcen nrocrif icdto some degrce during. manufacture, ancl thc alignr'enf ; i ih;molecules is not ideniical with thai oi-naturat f ibres such ascottol, Also, the fact that rayon is a nranulacturcd rnatcrialcnables us to control the physical charricteristics oI the Iinalproduct. We can nrakc the ,iyon .on.s" oi-fi,r., ̂ i i.;ih:i;.;r;i i;and e-lasticity, modify its lustre un,i -.oiorr.

Moreovcr, as unranufactured materiai, viscose rayo. is irol subjcct t; ;i.,;;;i,.,;cconomic and cl i . rat ic circunrstaiccs srrch ns t i rosc t t rnt nirccithc,propcrt ics ancl pr icc of a natural f ibre.vlscose rayo' conducts heat more rcadi ly than si lk c locs, andthe rayon has a cooler. feel against t r t . J ln.-vrrcosc is arso hirhrvabsorbent, and this enhances irs uoru" nr-o' . i ; i l i , ; ; ; ; ; ; ; ; , , i . " ' , ' tIhe .loss of strcngth which rayon

-uira.rgo., whcn wet isprobably its rnost serious shortcoming, biri mo.tcrn resin finishcshave done rnuch to overconte this lroblenr. properly finishcclrayon garments have high dimensionar stabi l i ty wtren ; . ; :

---"--

The introduction of. iayon staple has ciiaf:fcA manufacturcrsto blend rayon with other natural-ancl synitretic stapte nt;;;, ;;.irayon staple is used very largcly in this way. Rayon contr ibutcsi ts moisture absorpt ion and-other .cel lulosic ' character ist ics toblencls of stronger anct less absorte;a-h1;;;, inclucling nrosr oIthe synthet ics. Blends with polycster staplc are of prr t i .ufnii rnportance.Blends of rayon with ot l rer f ibres rnay be proccssccl by arry ofIhe . farni l iar techniquc.s. staple rcngtr i r

-nr" ' roviaccr to sui tpar t i cu la r b lends and sys tenrs ;a 50 rn rn (2 in ) s tap le , fu r . *u , , ,p1 . .ca' be ha'dled on cot io ' r 'achi 'ery 0,,)-n

- ibol ' i ;6; ; ; r ; ( ; ; , i ; ;

staple nray be used with wool.lVashing

In,. general, viscose rayon fabrics rvaslr<;e l lu los ic f ibres. I lu t v iscosc goocls.are( :ot ton, especia l ly when wct , ancl th is nrust

l i k c co t t on ; t l t c y n rol r r r rch lcss st rong tharra lways be rcrncrnbcrcc l

3_5

I I A N D B O O K O F T E X T I L D F I D R B S

w[c1 rayon garmel ts arc launclcrcd. Thc use o[ rcs i l l ' tu ishcs

has done n]uih to increase the dimensional stabil ity of viscose

fabrics when wet, but it is ahvays necessary to take great care

when wet rayon fabrics are bcing hanclled.Rayon fibre itself does not shrink appreciably, but a wovert

fabric nray unclergo progressive shrinkage, evcn whcu it has

been treated with a resin l inish to provide dimensional stabil ity.

Much depends upon the way the cloth has bceu constructed'

I{ayon fabrics wil l usually withstand tcmperatures u.p Joboil ing, but it is recommended that most garments should be

washed in hot water (60'C., 140'F.). In the casc of some knittedancl l ightweight garrnents, hand-hot (48"C., I l8'F.) or evcn

warrn (40"C., 104"F.) water should be uscd'hr general, the washing telnperatures for other fibres (except

cotton) are more restricted than for rayons, and rvhen rayon is

blencled with other fibres the washing instructions for thcse l lbrcs

should be fo l lowcd.Washing ancl b leaching agents ntay bc used as lor cot tot r .

Soap cloes not aflect t lre fibre under nornral washing conditions,ancl rayon wil l withstancl hypochlorite bleaches.

Drying

Rayon is an absorbent f ibre, and i t dr ies s lowly ' F leavy garnret t ts

nlult be supported carelrrl ly when they are ltung up to dry, or

they may stretch ancl lose their shape. Alter the labric has dried,tho rayon retains its original strength.

Spin clriers and turnbler dricrs may be used with ,rayongarments, but sp inning for too long nray increase the amounto[ i roning requi red. Hard wr inging tnust be avoided.

l rorr ing

lroning presetrts no special diff icult ies. 'Ihe

fibre is not ttndulyscnsi t ive to hcat , and i roning tenrperatures for other f ibres(except cotton) are more restricted than tltose for rayons. When

ironing b lends, the inst ruct ions for the other f ibres in the b lendshould be fo l lowed.

Rayon fabrics iron well with a meditrrn-hot iron (I-ILCC

set t ing 3) when s l ight ly damp. I f darnping is necessary, i t is bct terto ro l l the garment in a damp towcl than to spr ink le i t .

rri- I [ '1' I " l

3 6 3 7

A : N A T U R A L P O L Y M A R I I I O I T I I Sl)ry Clcal ing

Viscose is not af lcctecl by thc usual clry clcani lrg solvcnls, andviscose fabrics may bc . l iy . l"n,r.a 'aJ'JIIcct ivcty

irs cotton.

Iind Uscs

f ,*^r.:1 variety.,of fabrics can be rnade fronr viscosc rayorr, urrtlr r . rs now possible to use rayon i ' nrnking al , 'osi- ; ; i " ; i . i i ; ;traditional patterns ancl wcaves ttrat iiave^'rong bccn 'raclc fr.orrrnatural Iibres.

To meet specific needs, viscose rayoll is proclucccl in a witlcvariety of types ancl size.s,.a.ntl it is jossibi" to rirg t'c clrangcson fibre-properties by suitirbre "rtoi..'oi riyon ,yp". Thc softncssof handle of a fabric is incrcasccl, for cxirmplc' by usiug fincr{ i laments.Rayon in i ts nrany.. forms is astol ishingly and unir lucly vcr-sat i le. I t is usecl in evcry branch of t l ic-- icxr i fc i r r t l r rstry: nrcn,srvonrcr's and crrildrc''s outcrwca, n,r,i u'<Icrwcirr; rii i,,irrli,.,r:,and carpcts; household textiles o,ra nr.,fi.nf fabrics.

Crinrped llayotts' I ' l lcse

are f incl ing part icular ly i . rportant out lcts i , tuf tccl car. l )ctsarrd rugs, tuftecr crre'il les, curtains, -irlri.tort,.rv,

ancr .o'-wov'rfabrics for surgical use.

Sputr-dyecl Rayong:rtails and car. upfiolstery are applications irr which spun_dycdrayo' is of speciar inte.rcsi p.oviaing .*".lrtiorlnr rigi,i^ri^uiiiv.In,knittcd goods, blencts *lti, n".yiiin-l'r-c-J ar" poputar.Jersey knit fabrics have long fr.L,i o-pr*rvc o[ cotton, rvhiclrcxcels-in low shrinkag", goo,l handte o,rJ'"ou.r. Thc irrtro<.luc_tion of foam-backed i:g:i: ."J i;;i,,;;. 'r, ' lro*.u"r, tras targctycancelled out the advantages "njoyJ bt';ltton in thcsc rcspcct.s,and spun-dyed rayon has made-good lrcactway in this ficld.FIat FilanrcntFlat filanrent viscose is usccr w'ere increasecr Iustrc a'tr a fir'rcrIrandle are required.

An u.ustral but notcnt ialry i ' rportant orr t lct is iu trrc brc 'cr ingoI vcry short f lat- f i lanrent siaprc'with wooJ rrur ' , in trrc l rrocrtrc-l ion of papcr.

;. 1 I

t I I F F F F F I ' t ] . f f iI ' I A N D D O O K O F T A X ' T I L E F I B R E S

POLYME,R.MODIFIE,D VISCOSP RAYON

Ilv mixing stlbstances into viscose soiution before it is spun' the

manufacture, "on utt" ' ' in" conrposition of tbe extruded fi lament'

Spun-<lyect f ibre, lor "-^'ttpit, lJ t"Jt Uy adcling finely-dispersed

niqrnents to the vrscose*;J l ; l ; ; (see page 2 l ) ; t i tan iunr d iox ide

iriJa.a to dull the lustre of the fi laments'-fhis techniquc may i"itta t" moclify. the character of viscose

fibre in rnore subtle *"Vt, gi"ing it chnracteristics which are

required for particulat"^r]pii*t i""t ' Acldit ives may increase the

waier resistance of th; ;t;;;; i ;; ex-anrple' or give it an affinitv

i;;;r ; i ;*ide the "' i l tungt of viscose dves'

Tho possibil i t ies in#ini i i-t t i i t technique are almost in{inite'

and thousana, or *oa]i itJ;; i;;t have bien made' A few have

bccome of commercial imPortance'

lncorporatcd RnYon Staplc

Viscose may be b lencled wi th non-cel lu los ic polyrners ' inc luding

;;i;;;yi;;itrite ana ntt"Lyt "1":1"t.,,'^:,*monlv to tho extent

of about 10-20 per "tni ' Tltt" so-called incorporated rayons

nray bc made in " ;;; "^ti l tv of forms' depencling on the

nature and amouut "oi--^trJta

poly.mer' Features which are

generally conlmon t'" i i i tt"ft"rt omnitv. for acicl dyes' increased

;i;;ii"ili, bulkiness a'd wooi-like handle'

Cross-l inkcd I laYon

Polymers added to viscose may bring about cross-l inking of the

cellulose molecules' i; i t";;J;;"s thJ Jreerlom of movement of

the molecules with t;;;;t i t; each .other' and has the effect of

reducing water absoffit" ^"a *tff i"g in water and alkali ' and

increasiig the wet init ial modulus'

These improut*ti"t-io resistance to t.h: effects of water are

reflected in in",tu"i ' i i t t-tt ionul

stabil ity and washabil ity'

Fabrics also have u'lttttt nundle and increased covering power'

Grat tec l RaYon StaPle

Polyacry loni t r i le , polystyrene and other polymers may be added

to v iscose solut lon ,n ,u. t , a way as to produce graf t polymers '

The characteristics oi -ttr*"

depend upon the nature and extent

of thc grafting, tut t it^l"tftniqut is used commonly to improve

the dimensionat stabii ity of thl viscose' Grafted viscose rayons

3 8


Irave incrcased res is tancc Io water anr lswcl l ing. The c last ic rccovcry of the f ibrc isis more wool-l ike, ancl covci is improved.

Ilasilicd Viscose

alkal i , wi th rcr lucct lincrcascd, thc hancl lc

The int roduct ion of rayon staple prov ide<l I f ibrc that could beblended wi th other s taple f ibres, ' inc luc l ing wool . V iscose is acellulosic fibre, however, and it cloes not have an afl inity forac id.dyes comparable wi th that of wool . 1-he dyeing of f r i .nJ,of viscose and wool may therefor" pr.r.nl dif l icult ies.. By incorporat ing basic const i tuents in the v iscosc solut ion, i tis possible to produce Iibres whicrr hou" inipiouecr dyeabiritywiti irespect to acid and other dyestufls usecl in dyeing wool.. The additives may take ihe form of synil ictic-resinr, n, ur.,tin 'Rayolanda' ,

or casein as in .Cisalpnu;una ,Lacisanai .

HICI.I I 'ENACITY VISCOSE ITAYON

INTITODUCTION

-I 'he st retching of f i larnents c lur ing the spinning operat ion is afcature of all 'nocrcrn

. viscose- .."yo" l i .oarction ^proccsr.r."

t is te lns f ronr the tcchnique. of us ing iwo goclc t wh.c ls , on"rotating faster tha' the ot'cr, perfJctccl bi f. p. Wi1,",.,""1cor"r r taulds Ltd in 1914. This p iov icrec l a s i rnplc arc l e{Tcct ivervay o[ - br inging about the cor i t inuous or ientat ion of ccturoscnrolecules in the newly_formecl f i lame't, an,l so i,r..;n;i,;; ' t l ;;strength of rayon to a satisfactory level.. Since that t ime, research on ti," spinning o[ rayon has beenintensive and unceasing. t lvery urp."i oi-ui!.or" production andspinning has been studiecr , an, l in"r .ased unders^taudi" ; ; l ' i i ; ;factors involved has made.oossible the pioauction of rayons witlrc'aracteristics that are suifed to p".t i" i i- upptications. n;;h;;;the most i rnpor tant of these . r " th . h igh fenaci ty rayons.

T'e use of texti le varns as reinforceire't in ir idusiriaf apprica-tions has bee' increasing ropioiy-i"-i"rp"rt^".e during thc lasthalf century. High strength y".ns u.. ur.a in f,or, f ip"r,-.on-veyor bel ts , - tyres ancl othei appl icat ions of t f r i , &f i . . 'Vor timportant of a l l is rhe par t l l "y .a by rc infor . . . .n i ' t ; . ; ; - i ;

tyrcs, and as thc car and t ruck inc lust iy has growrr , so hns t .cc lcrnanr l [or h igh st rength ynrns in"r .os.d. - '

3 9

;FtI I A N D B O O K O F T E X T I L E F I B R E S

t l tan cotnpensatecl for by the increased tenaci ty , espccia l ly whcn

wet.These fibres have become the basis of the so-called 'Super'

h igh tenaci ty rayon yarns, such as 'Super Tenasco' , 'Super

CJrc lura ' anct 'suprcr lka" Manufacturers of tho super h igh

tenaci ty yanls cooperated in t l te t r tarket ing of thei r tyre cords

througir the Tyrex Inc. organization.

Molcculur Struc!ure' fhe physical character is t ics o[ rayon depend upon the molecular

structure of t lre tj laluents. All rayons consist of regeneratecl

cel lu lose, but the cel lu lose rnolecules may be of vary ing lengths,

ancl they nray be posi t ioned in a l l manner of ways wi th respect

to each othei and to the f i lament i tse l f . The uni formi ty of the

f i lamcnt may vary wi th respect to the nature and posi t ion ing of

the cc l l t t lose molecules.'fhe length of the cellulose nrolectrlcs is controllcd largcly by

the conditions under which the viscose solution is made' 'fhcse

may be such as to bring about severe breakdown of the cellulose

n.roicculcs into shorter oues. Or they may be such that breakdowtt

is kept to a min imunt , ancl l i t t le depolymer izat ion takes p lace '

The positioning of the ccllulose nrolecules in the fi lament is

controllccl primarily by the conditions under which regenerationancl coagulat ion take p lace in the spinning bath. The moleculesnray be proclucecl in such a way that the formation of crystall i tes

is at a min imum, i .e . the degree of crysta l l izat ion is low. Condi-

tions of spinning and stretching wil l also inlluence the size of the

crystall i tes, and the way in which they are orientatcd with respect

to each other ancl to the long axis of the l ibre. 'Ihese conditions

rnay also be used to control the uniformity of the l i lament

st ructure; some f i laments may be of the same st ructure through-out, rvhereas others may have a structure in the centre that is

d i f ferent f rom that of the outcr layers.These factors all have a major influence on the tenacity and

other propert ies of f i laments that are produced when rayon

is spun. By understanding and contro l l ing the tcchnique of

regenerating, coagulating ancl stretching rayon' therefore, it ispoisible to produce rayons to meet particular specifications. Itis in th is way that modern h igh tenaci ty rayons havc bcendeveloped.

42

A : N A T U R A L I , O L Y M E R T I D R E S

]',::,flil::l,i:" *.l

i.l :.:il,j"l or fi lir rncn r sr rucrurc i nrrucrrccst l t c c l t a rac t c r i s t i c s c l f v r v r r r r ( r r r r u r r t s t r t l c l t l l ' c t t t l l t t c t t c cs

.-fenasco, r^v^nc -"^r,,:,^,rlf:: nray

.bc ,sccn in thc rlngc oi,,i.." X":" :ll "ij y::: H:,n.y!" : y,, F i t' 1,.i,:," j' [ ̂ TiS;,; Isive i 'crease in ^tenacity

fr;,;";; i l ; j";;: ' t lrefc rs a prosrcs-

. - I . c l r a s c o ' . . T e n a s c ^ i i ' . ' . ^ ' . ^ ^ ^ . . . . . . � � � � � � � � � � � � � � � � � � � � � � � � � �''l;l' H'l'I;r ::, l' : ̂ :{:::iq" ;i;il -';;i :illll; " l" !l'-.?lJ.l. ;ll':,,:l?,'1.t"' ^'i,,i^" ?:ll : i J ;i: ; ""#

;.',; "',1;; :;ff :"i1"1'::Tf ?.1,* nra m.n t as -si, ";,,"; ; ;fi;, ii 1,, I iiL, jl"ll,

l tage 27, notably jn the out l i, - - .6v L , , ,u r . ru rv m u te o r r l l l l e o f the f i lanrc t t t s anc l i r t thcun i lo rmi ty o f i r i te rna l s r ruc tu re .

S1 ' I tUCTURE AND pROpEl t . l . l l ) .S (H igh - fc r rac i ry I l l yo r rs )

I l igh tenacity rayons arc crrcr ' icalry si ' r i lar to r .cgtrr .r . v iscosc;. 4 3

I I I IODUCTION

In the product ion of . l r ig l r . tc lac i ly . rayons, such as thc . . l .cr rasco,

Ili].i:.,|" :"agularion ancl stretcliir,r'J'ii," fibrc arc coprrolcct

iil+'ffi X,?"':1".:?:';l':,,1"ri:;"1::i:'lUliJ,J;;:':'Jfi fi ,i*i Li. I :ff ? J T :" lii :ti:ft , ln,T ",,,ri'"T .; i ffi J'i ff lf-: ll;: ITlese changcs jn tne ,tru.ti,?. ;i ';;;;;:ff , T,,: :f ilfl;nrilil n ih ;i:fi#, j:ll; I itiikff(.T"ily, 'Tenasco

Supcr I05,.Orcl inary viscose r iyon has a thin skin, and is higlr ly scrratcr l ,In^'Tenasco'

.higrr teriac]ty nr"r"."i,"irr"' i i.,i"t,,.ss of skin lrnsrncreasecl, and [hc serrario.s Ln;. ;;.;;;;" i"r, ,r.ono'rcca. .],^istrencl is ' raintai 'ecl in ' renasco-:si- i " '* i , i " rr t 'c tcrraci ty rr .srncreased. In ,' lenasco

Sup"r ZOI ',ir" '.or.

has <lisappcarcrlcnt i rely, and the serrat ions f in".- nf ,"ort ' i i r iprr .nr. . f , lcaving onlya bea'-shapecl cross_secri";r. i.i,l;l l;, ' i l"':.1cr0sco Strpcr 105,,thc-cross-section is alnost rouncl.There are now many techniques ancl adcl i t ivcs which nray bctuscd in producing therrecr ucin g "* t.n,i6i r i fy'.":T.:lil3l',::l;l il, J" ix:,#ffi l:il rirr'accepra bre aegrce.

-n.s.a rcti

-iii 'r r, t"i.i,i ' "r rayo^ prod uctiorrts as act ive today as i t has ever f r l . , r ,^ . , " f i t scems l ikc ly t^ntrve shal l see nrany new typcs of rayon ; ; , l ; ; ; , ,g in the I l turc.

iF t h l'': h h h F-|'':TT-F-F}-F}I { A N D D O O K O F T E X T I L E F I B R E S

Thcrnral Properl ics

High tenacity rayons have an improved performance

tenrperatures; tensi le strength and other mechanicalare affected less than in the case of regular viscose.

I. I IGIJ TENACITY VISCOSE RAYON IN USE

at elevatedproperties

The highly oriented molecules of cellulose in high tenacity viscoserayons present a barrier to water molecules and to molecules ofdyestufls in solution or suspension. High tenacity viscose rayonsdo not, as a rule, dye casily or eflcctively, and the rnajority oftheir applications are in l ields where colour is of minor impor-tance. They are predominantly industrial f ibres, more often thannot being bur ied out of s ight in a mass of rubber or s imi larmater ia l .

High strength, and the abil ity to retain high strength undersevere envi ronmental condi t ions, are the most va luable featuresof high tcnacity viscose rayons. They are uscd, for example, iuapplications where elevated temperatures are encountered, orwhere there is repeated flexing.

Tyre cords provide by far the largest outlet for these fibres.1 'hc phcnomenal growth of the car and t ruck industry dur ingthe present ccntury has created a huge market for tyres, arldfor the tyre cords that are used in reinforcing the rubber-in thetyres. Today, h igh tenaci ty rayons supply a large par t of thesetyre cords, and seem likely to continue doing so in the forseeablefuture.

Tyre cords are called upon to provide great tensile strength, andto retain high strength at the considerable temperatures generatedinside the tyre during use. They must withstand repeated flexing,and resist deformation. High tenacity viscose rayons have rnuchto offer in these respects, and they have ousted cotton from thisimportant market during recent years. The arrival of nylon hasdiminished the hold that high -tenacity rayons had established, butrayon reta ins a large por t ion of the tyre cord market , and i t isunl ike ly t l ta t ny lon wi l l change th is s i tuat ion '

Nylon competes witlt greatcst effect in the reinforcement ofheavy duty tyres for a i rcraf t , ear th-moving equipment and thelike. In these applicatiotrs, its phenomenal resistance to sltockloads g i r res ny lon the edge on h igh tenaci ty rayon, and i t a lso hasa higher strength/weight ratio. But in tyres for l ighter purposes,

4 6

A : N A T U R A L P O L Y M E R F I B R [ , S

including the mammolh.. crir tyre markct, high tenacity rayonretains i ts hold. The abi l i ty to lustain high tcnacity una .r in i .n-sional stability at the temperatures geneiatcrl i" ;"; it.;,"ii l.excellent resistance to farigue, and the price adva'tng"'oi r.,igr,tenacity .viscose rayons have enabled trrese fibres to-*iiririo,iJconrpet i t ion from nylon and other synthet ics in this f ie ld.The combination of properties -which

serves high tenacityrayons in tyres has been equally eflective in oth;; in-,;;;tn;riindustrial applications. Flexi6le rlbb.r belting is uscd for con-veying all manncr of materials, from coal anJ iron oie to p*i,and products moving down innumerable assernbly lines. .lherubber in these conveyor belts requires reinforcem*t, i;;i o;'i idoes in a car. tyre. And again, riigii t.nu.iff vis.ose ,^vf ", i i^*como into widespread use for tiis purpose. They provicle thehig.h strength, dimensional stability, iatigue resistance and llexi-bility that are needcd, and at moaesi cost]

-

Power transnrission bcl ts form anothcr i rrrportnnt scctor ofthis f ie ld, requir ing the same combinat ion of propcrt ie, in t f ioyarns that are used to reinforce them. Nylon,, ,up.iio, ..ririonl.to shock loading gives, i t .a useful advaniog. ou.r high tenacityrayons in some power.belt applications, bui f,igt t.ni'.itv invoilremains competitive where tli i i is not a vitar rJquirc,.,r.ni. "-'-"

I{igh tenacity viscose rayons .havc lnany othei applications inindustry, including the pro<Iuction of tarpaulins ancl protcctivefabrics, sewing thrcacls and umbrella fabiics, the rcinforcernentof hoses a'd of plastics used for bearings

-and ot'cr h";"t_J;i;purposes.

HrcH wET MODULUS (polyNostc) RAyoN.S

INTRODUCTION

Viscose rayon has now been in production for more than half acentury. .W.hen f i rs t produced, i t was a f i lament yarn o[ h iqhlusrre wlrch borc a superficial resc'blancc i ' trrese respects iolf j i j" l.u]|,<;

Its properries ctid.not,.howcver, bcar comparison wirhthose of silk, and it cornpcted iniiiatty iururs ur s'K' anq rt cornpcted init iaily i ' the continuous firamcntfield on the basis of relative cheapness ancl noveltv value.and novel ty value.. In due course, viscose rayon settlecl ao*n- ona-i.g^"-i" nraits proper niche in the textile field. It was acccptccl as a cellulosicfibre, in this respcct rcsembling cottonr which toulcl bc proctuccJ

47

I I A N D B O O K O F T D X ' T I L E F I B R E S

extremely cheaply from the cellulose available in wood' Its

shortcornings were accepted, and it found. its market in those

"ppli;; i i ;;; where cheapness was.o[ ovcr-riding importance'-"i-t- "*p.tience of viscose production grew' and the process

."ni" uni"t scientif ic investigation, improvements were made in

fibre quality. This tre;A has- continuect to the presen-t day' and

moclern viscose ,oyon--hot establishecl for itself a wide range of

^pJrc"ii"i i t ona outt"tt ' ' fhe production of viscose rayon exceeds

ij i i f "f any other man-made hbre, a'd this position seems likely

to ret r ta i t r for a vcry long t imc to come''-;;;; i i ; inir r"n.,oitobl! progres-' made.bv viscose^.ravon' aud

the continuous improvement in the quality of the fibre' viscose

i.tnin, unattractivJ characteristics which have been associatecl

;i i i ; i l t inl" tnt earliest t imes. These sbortcomings have preventcd

uir"tt. toyon from competing as -effectively as it might with tlte

natttral f ibre it most ncarly rcsemblcs - cotton'

A, u tnauufacturecl ftbrc, viscosc rayon has ccrtain advantagcs

over cotton. It is procluced as a contiuuous l i lament' of uniforttt

iffin;;;itv utia Jo"-tp"titio"' tt it cut into staple of anv

i.ngth, o, ,rri*t, ' ,r" of lengths' ' fhe p.roduction costs can be

assessed and controlted mo-re accurately than is possible w'it l t

;; i i ;n,-which is suUj"ct to all the.fluctuations of price and

pr"J""ti"t i typical of'a natural product'- And rayon' produced

i;;; " cheap^and oUunaant raw-material ' is the least expensive

text i le f ibre now avai lable.Thcse advautages have enablecl rayon to sustain atl inrportant

oosition in the tixti le f ield' But rayon manulacturers have Iong

fi;;iil ' ii;t ih; pore'riat of viscose rayon is only parrly

being realized; if i ts shortcomings could be overcome' ano IIS

orooert ics brought mor" ntnr ly In to l ine wi th those of cot ton '

iiffi;';;r;" ."""iO fr."onre tlie mosr important textile 'ibre of

al l .' thc deficiencies of ttroclcrn viscose rayons are the Same as

those t l ta t have becn wi th i t s ince the f i rs t f i lamcnts were pro-

ii ircect at the cncl of thc last century' Improvelnents have bcen

nraclc, but these have been largely a matter of degree'' Vittot. rayon is sensitive to itre effects of moisture' When

.oyon ls ru.t, i t abs;rbs water and swells, thc diameter of . the

fi larnent increasing by nrore than 25 per cent' At the same time'

ti i . t.nn.ity falfJ frV aborrt 50 per cent, ancl the e-xtcnsibil i ty

increascs by sorle 20 per cent' ' fhc irrit ial rnodtrlus of the rayott

f i f - l T r l r - I r I r r

4 849

{lil

III

IA : N A T U R A L P O L Y M E R F I D R [ , S

falls, and the l i lament wil l stretch in responsc to only a sntalltensile stress. Elastic recovery from such strctching is poor.'this

deterioration in the mcchanical propertics of rayon whcnwct is reflected in the behaviour of yarns ancl fabrics. Rayongoods do not possess the wonderful wet-stabil ity and washabil ityof cotton. They tend to deform when handled without due care,and undergo progressive shrinkagc.

Also, rayon docs not have the crisp, f irm handle that is socharacteristic of cotton. Rayon fabrics tcnd to havc a l imp andfloppy feel.

In reccnt years, rnuch has bcen done to inrprove rayon inthese respects. High tenacity rayons, for exanrplc, havc cnablcdrayons to compete eflectively in the important f ield of industrialtexti les. Cross-linked and chemically modified rayons havciucrcased the resistance to water (see page 38), and rcsin finislrcshave done much to provide dintensional stabil ity and waslrabil ity.

Dcspite these aclvanccs in rayon tcchnology, howcvcr, viscoscrnyon is s t i l l r ro nratch for cot tou in i ts bchnviour wi th lcspcctto water, or in the charactcr and crispncss of its handlc.

Stntclural Diflerences

In chemical composi t ion, v iscose rayon and cot ton are a l ikc;they are both cellulose. The diflerences bctwecn the fibrcs stcntfronr dil lerences in the physical structulc of the fi lamcnts. It isrcasonable to assunte, therefore, that by nrodifying thc structurcof the viscose fi lament, it should be possiblc to producc a rayollthat more nearly resembles cotton.

The micro-structures of cotton ancl viscose rayon have beenstudied extensively, and the dilfcrenccs bctwccn thcnr are welltunderstood. In cotton, the cellulose nrolccutcs consist of sonrc2,000 to 10,000 glucose units l inked togcthcr (i.e. cotton has adegree of polymerization of 2,000 to 10,000). Thcsc long cclluloscnrolecules are laid down in a wondcrfully precise and ordcrcdway (see Vol . l ) , forming a h ighly or icntated, uni fornr s t ruc-turc in which thcrc is a proport ion of crysta l l inc rnatcr ia l ar . r lount-ing to about 70-80 per cent .

The crystall i tes in cotton are oricntatcd with rcspcct to cuclrothcr, fonning fibreJike groups or micro-libri ls; thc rrricro-fibri ls,in turn, are arrangcd into fibri ls, and the fibri ls into fi lamcnts.The structure of the cotton l ibre is, in fact, ' f ibrous' all thc wayth rough.

rF F F F F F l. f-}.-}.-F}}:l} l_ f_ li H-rH A N D R O O K O F T E X T I L E F I B R E S

If a cotton {ibre is clisintegrate<l, e'g' by chentical treatment' its

micro-fibri l lar structure is displayed as it breaks up into ever-finer

nlarnents. With the help of the electron microscope, it is possible to

fo l low the f i lar lentous c l is in tegrat ion unt i l eventual ly the cel lu losc

nrolecule itself is reached; this is the finest l ibrous element of all.

In this wonclcrf ully organizecl micro-libri l lar structure of

cot ton we have the explanat ion of many of cot ton 's unique

characteristics. The high degree of orientation and crystall ization,

ancl the uniformity of the structure, enable the cellulose molecules

to cooperate effectiveiy in resisting a tensile stress. cotton has a

high tenaci ty .:fh" crysiall ine regions of the cotton fibre are not readily

penetrateci by water molecules; the amorphous regions-, into

which water can fincl its way, form only a relatively small pro-

portion of the whole. swell ing takes place as water enters the

cotton fibre, but without affecting drastically the strength-provid-

ing crysta l l i t re s t ructure; thc rat io of wct to dry s t rcngth is h igh '

1he highly-crystall ine, higtrly-orientated micro-fi bri l lar structure

of the cotton fibre enhances the rigidity and stif lness that is

inhcrent irr the cellulose molecule itself. Cotton is a stif l f ibre,

ancl this stiffness plays a part in giving cotton fabrics their

character is t ic cr isPness.The possibil i ty of reproducing this cotton structure in a viscose

filament seems remots indeed. The cotton fibre grows slowly,

ancl its architecture is established gradually and with great pre-

c is ion. Viscose rayol ' I , ou the other hand, is created rapid ly by

regeneration ancl coagulation of cellulose in the coagulating bath'

Simultaneous stretching aligns the cellulose molecules to some

degree, the extent of alignmenl depending on the conditions used'

Ilut even under the rnost favourable circumstances, the position-

ing of the cel lu lose molecules canuot be expected to match theprecise organization that we find in the cotton fibre.

Despite the obvious di{I iculties that face the rnanufacturer in

h is at tempt to nrodel l t is rayon on the cot ton p lan, great progress

has becn tnade in th is respcct i r l rccent ycars" fhc product ior t o fh igh tenaci ty rayons has taken us some way a long the road;

soine of theie rayons have nricro-l lbri l lar structures that begin to

look l iks that of cot ton. Even ntore impressive progress in th isdirection has taken place with the developnrent of the new typesof v iscose rayon whic l t have become known as h igh wet modt t lus

( l lWlv l ) rnodal and polynosic rayons.

50


High lle t MoclulLts Moctal atul pob,nosic lla1,s115'fhe mai' structural crirTere.ces ber.ween viscosc rayo' and cottoncan be sunrmarized as (a) difrcrences in thc crcgrcc or pory,tr.. ir-n-

tio' of the cellulosc morc.culcs, ancl (b) crirlererices in ttr" ̂ rruir["-nrent of these molecules in the fi lan.rent.

By the 1930s, understanding of the v iscose rayon proccss wassuch that methods of irrrproving rayon in botir t l ,;r" .;r;.; i ;rvere know'. It was realizcd, for ciample, that brcak,l";;r-; ithe celhlose molecules took place cluring the agcing of thc alkaricc l lu lose, ancl in the r ipening of soJiurn . . l lu lor . xa. thatesolution during viscose procrui.t ion. Ry avoicring 1i*r.

-ri.g.r,

viscose solutions coulcl bc macrc i ' whicli the molcculcs or soaiuri ice l lu lose xanthate were longcr than in normal v iscose.

.The. developmcnt of h igh tcnaci ty rayons had demonstratec l ,also, that the structure of trre fi lament .outa be influcncJ i l;t l iby contro l o f the spi .n ing condi t ions, In general , thc s lor ier thcrcgc.crat io ' ancl .coagrr l ' t ion of thc cc l l t r lo ic , tho iuorc ct tcct ivc ivcould st retchi r rg bc uscd iu o ' icutat ing thc cc l ru losc ; "1; ; ; i ; ; .

' '

.By 1he late 1.930s, rayons.were bein! nrade in rvhich the Acgi."of polymerization of the cellulose *oi i,r. i.or.d by moclif icationof , . the v iscose product ion process, and thc or icnta l ion of thcccllulosc was improved.by siowing tlr. ,"g.n"r,,t ion nnJ "onl,i in_tion of the ccllulose fi lanrcnts Gee ll igli ienacity ftnVo,i, ing.3 9).

Dur ing Wor ld War I I , fur thcr progress was nraclc a long thcscl ines, notably i ' Japan. In 1951, th ls work culnr inatcc l " i r r

thea.pplication for a patent by S. Tachikawa, covering the protl irc_tion of viscose rayon by a icchnique which'yielclcd fibres of novcltype. In .particular, the. Tachikaw" .nyon, wcre strongcr i lrarrregular v iscose, wi th rec luccd e longat ior i , a 'd they f r .a i gr"o i iVinrprovcd rat io of wet to c l ry s t r ingth ' (7 i per cent , cornparcc lrvith the 56 per cent of regular viscose). i lr is ln.r"nsecl resistanccto the eflect of water was reflcctecl alio in a high *.t ,"oauii",wi th Iower water imbib i t ion ancl rcc lucccl swcl l ing.

..,] ' f. l-.* tYl?: o[. rayon <lif lcrccl structurally fronr rcgularvlscose rayon. The ccllulose molecules were longcr, with a dJgree

of polymerization in thc region of 500 (cf. ordinaiy rnyon ntioi, i250).. Also, disintegration of the fi lanicnt <Jisplayccl 'o

,, i i .ro_f ibr i l lar s t ructure wi th a rcsemblance to that o[ cot ton.

Development of the Tachikawa proccss in Japan lc,l to theproduct ion of h igh st rength, h igh wei modulus rayons which wcrc

5 l

9:!!,!AustriaBelg iumEnglandFranceGermarty

I ta lySwitzerlandr 4 n e , 1

I I A N D I } O O K O F T E X T I L E F I I ] R N S

rIWM MODAL POLYNOSIC FII]RES

Firnr

un enr lelaser-Lenzr ngtrabeltaCourtaulds Ltd.

Fibrc Trade Mark

Snia ViscosaViscose SuisseDaiwa Spinning Co.Fuj i Spinning Co.Mi tsubishi Rayon Co.Tei j in Ltd.' l 'oho

l{ayon Co.' loyobo

Co. Ltd.Avtex Fibers Inc.Amer ican EnkaCourtaulds N. Anrerica

SuperfaserZ 54 (Zaryl)Vincel2 5 4Poly{lox,Super PolyfloxI(oplon2 5 4PolynoJunlonHipolanPolycotM 63 (Tovis)'f

u lcclF iber 40, Avr i l .Zantre lW 63 (Lirelle)

U.S.A.

nrarketed as 'Toramornen' andrayon have been developed iuproducl . ion.

NOMENCLATUITE

later 'Tufcel ' . S inr i lar typesot l rer countr ies, and are uow

o fi n

In the Iate 1950s, viscose rayons produced by the new techniqueswere being dcscribed in Europe as 'polynosique' rayons. Thisterm was derived, presunrably, fronr a conrbination of 'poly', toindicate a high degrce of polynrerization, and 'cellulosique'. ' lhe

term was subsequently modified to 'polynosic'.

In its original sense, the term 'polynosic' was restricted to fibresof the high rvet modulus type produced by techniques similar tothat dcscribed in the Tachikawa patent. In the U.S.A., an ofl icialFederal Trade Commission definit ion was coined, using a highwet modulus as the cr i ter ion, i .e . extension at 0.5 g. /den (4.4 cN/tex) being not more than'35% in water (see page 53) . T l ie term'polynosic' has since been used with less precision, to describehigher-strength rayons of the increased wet-strcngth type. Thesedo not necessarily mect the requirements of the F.' l ' .C. delinit ion.

52

, . , 1

A T U N A L P O L Y M I ] I T F I N R E SIn pract ice the tcrrn "rr igrr wct nrodurus" ( l rwM) is cr,rrrr . rr lvrused to describe a broacl la'ge of fibr;"i iti i; iy;;.,l i;;"i;;;i"polyr.osic"

being used for t r iose * i ih ' th. higrrcst wct rrrocrurrrs.'Modal" is widery usea ur o gru.r i . i ; ; ; r ' i ; , regc'c.rrcd cci luroscf ibres obtai 'ed bv orocesseJgiving a ' igrr ie.aci ty a'd a ' ig ' rvctrrrodulus-

'fe xrile Ittstitute Defirtitiort:s (IJK)Polynosic Fibre A.reg.'re.tcci cellulose flbre that is charirctcr-ised by a high i r i t ia i w-et 'uoaurus oi eiast ic i ty a 'd a relat ivcrylowdegree of swei l i rg in socl ium hyaroxir te sol t i t ic, ' .

- -- ' - -" ' "r

Modal Fibre Geneiic name fo; ,.g;;;rtccl ccllulosc l.ibrcsobtai 'ed by processes givi 'g u rr igl i " i . i iuci ty a 'd a rr igrr wctrnodulus.

Federal Trade Cotrrrtri.ssiotr Delititiotr (U.S.A.)Tlrc.terrn polyn.o.ric: fibre rtas bccn clcfincd try thc u.s. Itctlcrrrl'frade

Comrnission as follows:Polynosic Fibre. A rnanufacturcd cclltrlosic fibre with a firrcand stable micro-f ibr i i lar structurc which is rcsisrant to trrc act ionof 8 per cent sodiurn hyclroxidc solution down lo 0.C., ;l,i;i istructure results in a nr ininrutn,wet strcngth "f Z.Z gtd", f ' t i . icN/tex).ard a wet elongat ior i "r i .* i i i r r i t : . , pcr ccrr. at a sr.rcssoi 0.5 g/den (4.4 cN/texj

ryPES OF TIWM MODAL FIBRE

flwM rnodal fibres all rr* ,r*irrowi'g propertics i, coruror:

!]J |rlgtr wet modulus, i.e. resistance to extension when rvct(2) increased ratio of wct to dry brcakin! icnacity(3) increased resistance to swclting Uy cairsiic alkalis(a) high degree of polymerizatioi oi ""tiuior"(5) nricro-fi brillar sl.rucrure.

These charactcr ist ics are sharcct witrr cotto. nnd otrrcr natur irrcellulosic fib-res, and for this reaso' 'wM iiiouar fibrcs are so'rc-thnes cal led'art i f ic ial cottons' .

Thrcc Types

Dcspite these charactcr ist ics which al l r- l rv lv l rrrodal f ibrcs havc i rrconlnron, thc individual r-rwM rrr'cral fibrcs dif|cr rru,n ,,,,. ,i i intl,.i53

.-r-r-------- f f i l - f- l-_-HHl

I Iig l r S t rength


III|M Modals

A : N A T U R A L P O L Y M E R F I D R E S

. .(.3) lt iglt Elongatiotr HIrM l; ibres. r 'rrcsc arc crraractcriz.cd byl l ieh 9 lo lqat ions, dry and wet , c .g. in the rangc 12_14 per ccrr tdry; 16-20 per cent wer.

-Fibres belonging to each o[ these thrce groups, and thc rangcsof properries- they clisplay. are shown in itr. i^frf" o,i-pre"'3a.'fhe table also i.cludes corresponclin j propcrties oi ;;; i ,,.-,;rayon staple and of a reprcsentit ive cotton (uppcrs).

PI{ODUCTION

'fhe pri.ciples Iollowccr in the procruction of high wct nrocrurusrayon by the Tacrrikawa technique are (a) .Jar"tio,r--in

' i t iJ

amount of cellulose breakdown whlch takes pln"" iu if,. 'p;;.;;:t ion of t^e viscose solution ancl (b) sto*lng .fbw,, of tfr" , ig"'n;r;_t ion.and coagulat ion of the f i lament , p" . i r i t t iug , t r . rc l ' i i i lo ' f r .carr ied out gent ly ancl in s tages..,."|,f,.r^:.| l t...1.-in productiori of a IMM rrrotl lI nryr.rn by tlrclac l ) lKawa process arc as fo l lows:_

.( l ) Soda cc l lu losc (arkar i ce l ruro-sc) is procJucct l by stcc ' i r rg t r rccel lu lose in causr ic soda, . fo l low.a r iy p i " r r ing a,< l , i r rJ ;1f t ' ; ;i ' the product io . of rcgular v iscose. rde conai t ions are cnrcfu l rvcontrolled to ensure that the temperature .lo; n;; ' l ;"; i l ; l20 'C. , and the process is completcc i wi th in 2 horr rs .

(2) fhe theorct ica l quant i ty of carbo ' d isu lphide is usccl inxanthation (less than trre theorcticar .quantity is t iscd i ' .t p."J".i,.,g

regular v iscose) , ancl the adcl i t ion i , nr"a l ovcr 2[ hours, T l rctcn)perature is held below 20.C., a'cl the. raisccl to ZS"C- f", ihou r ,

(3) Sodium ce. l lu lose xanthate is d issolvc. i ' watcr to prov iaca ^solut ion conta in ing t r rc equivarc ' t o f 6 l ier ccnt cc i lurosc arr t l2.8 per cent sodium hydroxidc. (ln the regular "ir;;;; ;;;;;;;xanthatc is d issolvecl in caust ic ioda solut tn. )

' . - - - '

(4) The solut ion is -soun by extrus ion in to a bath of vcrydilute. (1 per cent) sulphuric acicl at ZS;i. -f-f,. f i lamcrlts arcst retched in s tages to three t imes thei r spun lcngth a l ; ;J ; ;v iscose is ext ruc led i r to a bath co ' ta i ' ing io pcr c-cnr , i ; ip l , i ; ; ;

ac id, I per cent z inc sulphate and aboi t lg pcr cc ' t soc i iur r rsulphate maintained at 45-55'c. rhe aeliee of srretcrr ,r.p;;, i;tupon the type of rayon bcing nradc.)

Standat 'd_High

E long 'n

SuperfaserFiber 40(Avr i l )

a a A ^J J - + L

2 t - 3 0

12-1416-20

53-801 0 9 - i l 5

6s-7 5

CottonUppcrs

RayonStaple

Tenacity (cN/tex)drywet

I :xtensibi l i ty (%)dryrve t

Wet lv lodulus (cN/ tex)per l00d/o ext 'nat2Vo exl'rta t )7o ext n

Super Po ly -flox

Jun lonw 6 l(Lirel le)

4 l - 4 630-35

6 - 1 08 - l 4

2 5 4VincelPolyf loxKoplonPolynoHipo lanPolycot

28-35tB-27

8-t29 - t 6

98- r s9r24-247

5 5-70

J L

3 5

l 822

9l 0

3 544

i Ut)1 5 9

221 2

I J L - L L I

221-353

65-7 5 50 90-100

in properties over a wide range' Air-dry tenacities, for example,

n loy Ut 28.3-4 ' l . '7 cN/ tex (3:? .5 .4 g/den) ; wet e longat ions may

ranse f ronr 8 to 20 per cent . wi th in th is wide range of propert ies,

horicver, it is possiblc to classify the polynosic l ibrcs into three

rnain groups, as proposed by J. D. Grif l i ths of Courtaulds Ltd'( l 'ex l . Ins l . Industr . , 1965, 3, No. 3, p. 54) :

( | )Highstrengt | tH| |MFibres.Tl researecl raracter izedby. l r ig l tt . t ioJi i i . i , Jty ui ta wet, e.g.40.6-45.9 cN/tex (4'6-5'2 gidert)

dry;30-35.3 cN/tex (3.4-4.0 gi den) wet '

(2 \S tandardH| |MFibres .Th isgror rp inc ludes t l renra jo r i t yo f"" i ; i r ; ; ; nbres. Te.aci t ies 28.3-35.3 cN/tcx (3'2-4'0 g/dert)

tkv' . . 17.7-26.5 cN/tex (2.0-3.0 g/den) wet. Elongat ions in t l te

r rnge 8-12 per ce t t t d ry ; 9 -16 pcr cent wet '

5.1

llwlvt MODAL FIBRES - COMPARATIVE PROPERTIES

55

H A N D D O O K O F T E X T I L E F I B R E S

Under these conditions, the degradirtion of cellulose is helcl

to a minirnum by the omission of ageing and ripening stages'

and by the milder conditions used in preparing the viscose

solution. The regeneration and coagulation of the cellulose takesplace slowly and gently in the dilute acid of the spinning bath,ivhich contairrs l i tt le or no salt. This pernrits stretching to be

carriecl out graf,ually, allowing the molecules to assume a higlt

clcgree of orientation and crystall ization. The fi laments produced

arc of nrore uniform conrposition; t ltc cross-section is round.The degree of polylnerization of FIWM rnodal f ibres produced

in th is way is about 500, i .e . about twice that of ord inary rayot . r -The coiclit ions describecl above are typical of those used in

I lWlv l rnodal f ibre prodtrc t ion, but thcy may be var ied i t t a nutnbcrof rvays to provicle fibres of the desired charactcristics withit lthe l ' lWM ntodal range. The coagulatiotr bath, for exantple, mayconta in sulp l tur ic ac id and sodium sulphate in vary ing propor-

t ions. Z inc sal ts ntay [ :c uscd to s low thc rcgcncrat ior t o f cc l lu loscby lorming zinc cellulose xanthate (sce page l4)' Forrnaldchydcnray be adclecl to the viscose solution or to the spinning bath,[orming an cster between the xanthate and thc formaldehydc,which also serves to slow the regeneration process.

PROCESSING

IlWlvl nrodal f ibres are essentially cotton-like itr character, and tlte

init ial ernphasis in staple productiou has been to provide staplelengths ancl l inear densi t ics sui table for use ou cot ton spinningrnachinery. The setting of cards, drawframes, etc., reqttircacljustment, to suit the particrrlar f ibre being processed, but

there are no major d i f f icu l t ies i r t producing HWM modal yar t rs toa wide range o[counts, frortt coarse to fine.

flWM modal f lbres share with other man'made fibres the advan-tages of uniformity of staple and linear density, and yarns maybe produced frorn them to a much higher standard of unifornritythan is possib le wi th cot ton.

I IWM nrodal f ibres are a lso spun and cut to l inear densi t ies ar tdstaples suitable for processing on woollen worsted and flax equip-men t .

Weaving and kni t t ing o i HWM ntodal yarns is s t ra ight forward,the bcst r isu l ts in wcavi -ng f inc count yarus bc i r tg obta incd at rc la-

t ive l rurr r id i t ies of 7Q% and above, as in the weaving of cot tot l '

r

A : N A ' I U I T A L I ' O L Y M E R I ' r t r R l J SlI lcaclr ing

Hypochlori te, chlori tc a1t{ ]rydroqcn peroxidc blcachcs rnav bcused safelv on HWM mo<rar ri6res-trrl ir.r"i.i.r*"1;;;;;;ili,.;."[ibres means, however, that rcss arorti""- "on,rit ions nray be uscrrto produce whites equivarent to rhosc obtai'ccr *i ir i "i i ,., nrrr*.As wi th a l I cc l lu los iot ibrcs, overblcachi"g ' in"y cause acgradat io 'and should be avoic led.

I)ycirrg

All the usual tvoes of dyestufls for cellulosic l ibres tnay be use clon I-'WM modaf fibres, i";i;dl;;-;ir*tl'urt, uzni., reacrivc crc.lt].9.,r..r,u1, thc dycing properrie; uiiiwrur rnodlls lre ncarcr tocotton trran to ordi.ary visco.se rayor, bui t t , . u'r i ,r i t ,cs oi l i , i ividual HWM nr.dar f ibres varies co'sidcrabry. 'r ' rr is is rrart icurrr lvnoticeable witn direcr dycs. Thus, ; At;;i;iii;,,;i i;;;.,';;';ii;iiifor one ttwM 'rocrar .q,iiu,,t.itiiu'rrr;i il;i,,;*.r'ii,i .,,ir.,,,,";h;,;lus thc s..rc dvcstu|r 'wi l l h've urr ' l ' l i rr i ty Ibr .rr, thcr l lwM rrr.t l , lwhich is closer to that if ;lqplry;i;;;;iiuuy viscosc.'l'rrc rangc of avairabrc .ry.ri,,ri,'ir- sii';ii. ilili;rrrr.rst cvcrvshade of requirecl fasrncs-s.'to *n.t,i,,g, riglii pir.rri;;ii;;;,,";;;:can be produced on any I-IWM nroclal n;r;."

Ir inishing

l l lvM modalrayot ls are gcnera'y sir ' i lar to cotto ' i ' t r reir chcrrr icr lnnd physical structurc, gl :1. t r i .v , . rpouj ' to f in ishing in nruclrt 'e,same.way as corron.I IwM ; i iodalsi ; ; ; ; . grcarcr rcsisra'cc t .swel l ing in caust ic alkal is.r t ra, , oiai i r l r f -u,r .or. ,

nrr t l t 'ey wi l l,yi t]l*i"d merce rizing concritions. ni.xir i."ce of r rwM r,. .hrsls noI as great as t 'at.of cotton howevcr, n,,a it isl,rri;ff i ,; ' i ;tusc the ful l rnerccr jzat ion process with lOtf % f fWU rrrodul labr ics.I^i: i:, in any case, un.ecessary as I.IWM

-riioct ri"iJrr., ,i,.ybc fully set, stabilizccr.ancr given lncrcasecr crye arlinity by trcnt-nrcnt with caustic soda .noi cxceeding ellrt p", ccnt. _I_his

con-centrat ion causcs no signi f icant loss ot l l ropcrt ics, ancr i t is uscfulils u 'retreatme't for various rcsin applicatiorrs,'anrl f; l;r;;;colour. y ic ld i rr pr int ing.l (esl ' t reatr l re ' ts uscd with cotton rnay bc appriccl to l r lvM'odals, e.g. . to provide increased , tur l i t i iy incr to bcstow cuse-, [-care pr.opert ics. I lwM r 'odal fabr ics subjcctcr l t , rcsi ' t r . . i i "cr i tsuflcr loss o[ tensilc an. tca*tr"u!ttr' ro

-ir lcsser cxtcnt than

57

[ I A N D D O O K O F T E X T I L E F I B R E S

cot ton g iven the satne t reat tnent ' This Inear ls that I IWM modal

fabrics of given crcase-recovery ancl ease-of-care pro-perties wil l

be stronger than cotton o' 'nyo'l fabrics o[ equivalent crease-

,*"""iv'^"a .or"-ot-.n'" ptop"ttitt ' The amottnt of resin neccled

to attaitr a particular levei of these prope.rties with l-lWM modal

i;;;; l ; t.t ' i inan witlt cotton or ravon fabrics'

STRUCTUI{E AND PROPE,ITTIES

li ine Structure and APPcarnncc

I IWM nrocia l f ibres are typ ical ly of rouud cross-sect ion ' and do

tr"i aftp V any skin "fttt ' fn" micro-structure is f ibri l lar' the

Il lament breaking "p-l;t; smaller ancl smaller f ibri ls whcn

disintegratecl for example by nitric acid' The fibri ls are distributed

uniformly throughoui the fi lamettt cross-section' producing . a

honrogctteous structure. iht t ltgtt". o.f polynrerization is in the

;;;i;;i;i-i00. til; a.ei.. oi cryii,itti'rity ori twtr/l nrodal libres is

in the region of 55 per ceut, compareci with 40-45 per cent.for

;;ii;;ty ";;t"n

nna ^;o-so

f"t "titt {or cotton' The crvstallites

i; Hivi',i tnoout libres are larger tharr those in ordinary rayorl'

The clegree of orientatiori of the long cellulose molecules' in

both the amorphous utJ 1ft" crystalline regions of the fibre' is

itiglt.t in HWlvimoclal fibres tharl in ordinary rayon'

Terraci tYHielr Strength: 4l-46 cN/tex (4.6-5.2g/den) dry;30-35 cN/tex

-(3.4-4.0 g/den) wet '

sto) i io,a, ' i | - ts ' .N[.* Q.2-4.0 g/dcn) dry; l8-26 cNi tex

(2-3 giden) wet 'I{ielr Elonga tion: 34-42cN/tex (3.8-4.8 g/den) dry;21-30 cN/

"tex Q.4-3.4 g/den) wet '

Elongat iort

l l i gh S t rength : 6 -10 per c€ t r t : t t y , ; ,S- l ,4 . le r cen t wet '

b l , i , rdarc l : 5 - tz p . t c ' cn t d ry ;9 - l6 pcr cc t t t wc t '

; i tdf t i ; ;s; t ioni rz-14 pei cent drv; l6-20 per cetr t wet '

Elastic RecoverY

Elast ic recovery is higher ior I IWM ntodals than for cottou or

t .V"t t- t i "pf . , eipecial l "y in t l te wet state' ' Ihe fol lowing diagrant

58

/ /corToN

ll lvA' l Modal Ir ibres. ' I ' rrc relat ionsrr ip between rvork do'c in strctcrr incr f ibre when wet and the

l- ibres with respecr to or;, | : .T1Lent set ' 1he srrperiori ty ot l lwi l t rnoJai

,noaor rot'ii.,"51"'rJL;{l^._"il: ill,.,il:l,i tlf"fill?,l,i';ii:l,l',x:l,y|ltreatnrents than either cotton or "i.t i , i" iy i"y* i i irr,", _Cour t c sy J. D. G rifl'it h r

, lH r-t

,, I

jII

IiI

IrilitliIIilr ,

il,ItitllflIIInHlr,

li


shorvs thc work done. in s t retching a f ibrc w^c ' wct , ancl t l repermanent set (i.e. 100 per cent nrinus elastiro r t h e t tr,.. c r ols. s ;l ! ry r,,L ;1 ! ;T;; ;; i ?;; l,,j ii.i,l 1,1 Io',j,ilil'J]rayo' staple. The su periori ty of I-IWM,"oaui, in rlr ir ;;; i ;; ;r;;;;,t,t 'at fabrics rna.e from ihern are tess sut lcct to pe.t. la'c'tdeformat ion dur ing wet t reatmetr ts than e i ther cot ton or ord inaryrayon staple fabr ics.

o.8

z-t\

Y

3 o .oU

trl

(,z:rH o'aUq lF I\ n l

HIGII ELONGATION

2 3PERMANENT sEr (1")

STRENGTH

ORDINARYRAYON STAPLE

59


lni t ia l Modulus, WetLess tlran 3.5% elon}ation in water at 4.4 cN/tex (0.5 g/den).Fligh Strength flWM Modal:

132-221cN/tex (15-25 g/den) per l0Alo ext'n at 2Vo ext'n.221-353 cN/tex (25-40 g/den) per IOO% ext'n at SVo ext'n.

Standard l lWM Modal:88-159 cN/tex (10-18 g/den) per l lVo ext 'n at 2Vo ext 'n.124-247 cN/tex (14-28 g/den) per l}V/o ext'n at 5% ext'n.

I-ligh Elongation FIWlvl Modal:53-79 cNi tex (6-9 g/den) per l)Vo ext'n at 2Vo ext'n.8B-l l5 cN/tex (10-13 g/den) per l lVo ext 'n at 5% ext 'n.

l i l tcct of I\ loislure

See fcnaci ty and ot l ter tensi le propcr t ies 'Wa te r Imb ib i t i on :

l - l igh Strength l ' lWM Modals: 65-75 per cent .Standurd I " IWM Modals: 55-70 pcr cct t t .High Elongat ion I ' IWM Modals: 65-15 per cent .

Increase in d iametcr on wet t ing: l l .5-15 per cent . This is in ter ' -

rnediate between cot to l l and ord inary rayon staple. HWM modal

f ibres swel l less reacl i ly in aqt teot ts sol t r t io t ls th lu ord inary rayol l

s taple docs.

Mtect of Alkalis

[ {WM modal t ibres swel l n t r tch less than ord inary rayon staple '

They wi l l wi thstand t t tcrcer iz i t tg cot td i t ions.

Chcnricnl and Biologicll Propertics

Gcneral ly s i r t t i lar to other cel lu los ic f ibrcs.

I I IGH WET MODULUS RAYON FIBRES IN USE

IlwM nrodal l ibres have brought to the texti le industry a viscose

rayon rvhich approaches cottou in character, notably in its

behaviour with respect to water' The high init ial wet moclulus

of HWM modal f ibres is reflected in fabrics which are highly resis-tant to deformation whett tvet; they wilt withstand the strcssesi rnposcct dur ing launder ing ancl wet processing general ly wi thouttunclergoing shr inkage to a s igrr i f icat r t cxtc t t t , and rv i thout t re ingpu l l ed ou t o f shape .

t r . , I

60

A : N A . T U R A L P O L Y M E R F I S R N , S

This dimensional stabi l i ty under wet condit ions is pcrhtps thcr 'ost. l ,portant character ist ic o[ I rwM r 'ocl ' t r ib;J; i i ; ; ; ; i l ; ;pract ical . .point oI v iew. But r-rwM mocrar f iures'rrry ik"t . gir ;"a so[t, si.lky handle that cliffers fronr cottorr or viscose.

lVashing

F'abrics made from FIWM-nroclal.fibres nray be wasrrc. rcpeatccilyrvi thout. undcrgoing_.,dcformation or._ i rogrcssivc slrr i r rkagc.Laundering charactcr ist ics are gcncraty si i r r i lar to trror." i r ico l ton .

Ironing

l lWM modal fabr ics i ron l ike cotton.

Dry Cleaning

l- lwM r 'odal f ibres are vir tual ly purc cci l rr losc, nrrr l arc rrr t n| f 'cc.1.9,,t tv dry clc' ' irrg survc'rs. riabrics r. ' t lc ir.r 'r rrrvlri ' i iui, irl lDres n lay l re dry c leaned as readi ly as cc l t ton.

lind Uscs

The d i rnensional s tabi l i ty of I IWM nrocrar fabr ics wrrerr wct r*sgive' tnern the e'rrde.inio virtualry .u.if t ' i . t,t "a,r;;ri;; i i ;,; ' i ; ;which cotto. is uscd. I-rwM r'odal fabrics irc strorrg, ri,ir,i ,;;;;i,,;;d inrensional ly s tabre, r rn i lornr ano -

o i gooct ha.c l lc i r r rdappcarance.

,, ' l ' f ,c

1o,or stabil ity of orclinary viscosc rvhcn wct has clcnicdr t access to nrauy important apl l l icat ions, inc luding ,ou.n nuJknitted shirtings,

-blouscs., knittcd una.r*"n.. a'<I outerwear gar-r ler ts ' But HWM ruodals 'ave 'ow rr i "urcL v lscose to corrpcteellectively with cotton in e.ncl uses of this iyfc, cspecially trrose irrwhich a sof t , s i lky handle i , oa"oning.J i rs . In pr in tcd drcssfabrics, for exarnpie, HwM ;"dri;';;;fre a conrbi'atiorr ofstabil ity, subduecl jrrsire and attractive hancJlc.

Dinrensional s tabi l i ly at vary ing hurnic l i t ies is an i rn l tor tantfactor in the fiercr of curtain'"rit"i i"fr.-burtaius nra<Jc fro.rordinary viscose staple are l iable to alterin l ingth fronr scilson toseason, and even f rom morning to evcning, as i rcsul t o f c t rang"sin^hunridity. But rhis p^e.nornJnon .;; i ;; ou.r"o,u" by rhc uscof l{WM nrodal yarns in the warp of i l iJ fufrrj..Cotton interlock fabrics tc.cl io bcco're lrard a'<J boardy, a'cl

6 l


STRESS-STRAIN DIAGITAMS _ I{WM MODAL FIBRES

o 2 4 6 .roo?,* (r l?or"Jrlo*)

'o 16 18

l. Air-Dry. This diagrant, b:rsed on air-dry condit ions, compares thethree types of l{WM rnodal f ibre rvith cottons, f lax and rayon staple.Cotlon. The region covered by the curves for various cotton f ibrei isindicated by the shaded area. ' I 'he upper margin of the arer represents thestress-strain curve of a Sea lsland cotton (St. Vincent); the lorver ntarginrepresents the curves o f typ ica l As ia t i c co t tons (Oonr ras and Benga ls ) .The breaking tenacit iesof various I igyptian,American and Peruvian cottonsare ind ica ted by po in ts .Hlltl[ lr[odal Fibres. Curves typical of the tlrree groups of HWM modalf ibres are shorvn. I t wi l l be seen that (a) the curve of the high strengthtlWI' l modal group closely resenrbles that of Sea Island cotton, (b) thecurve of the standard HWM modal group resembles those of uppers,American lvl iddl ing and Peruvian cottons, (c) the curve of the highe longat ion I IWM ntoda l g roup l ies w i th in the area o f the co t ton curves fo rabout the f irst 5 per cent of exterrsion, but beyond this point i ts highex tens ion takes i t rve l l ou ts ide the area .Flax; Rayon Staple.The curves for f lax and rayon staple represetrt approx-irnately the trvo extrerr les of the total range of cel lulosic f ibre curves.

See diagrant oppositc for f ibres in the wet state.

--:

o

0

U JCT

a

the sur face takes on a fe l ted appearance, when subjected torepeated rvashing and turlble drying. l lWM modal interlock suffersnone of these dcfects, and reta ins i ts in i t ia l appearance andhnnd l c t h ro t rgho t r t n ros t o f i t s l i f c .

H STRENGTH

62 63

5

o

t4 1

bJt

6 z

N A T U R A L I ' O L Y M B I I I T I I ] I I . E S

}]rcH srRErucrH

STANDARD

II IGFI ELONGATION

2. llet. Tltiswct stf t tc.

4 6 8 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4srRAtN (% e lorucarroru)

diagrarrr shorvs corrcspondlng curvcs lor thcso fibrcs ln thocot tot r ' T 'e breakins te.naci ty . oI cot tor f ibres.r ras l r rcrcascd srgrr t ly ,9.,:ql!t.tC has been a si-gniticanr it,op i i i f i i i t irr ' ,n'oii,,,,r.l l l lM Modal Fibrcs.-'f|rcsc all sl i.w ioiu.i 'r] i*it i ,rg tc' ircrtros and rrr_creased brcaking extensions, which are .ui. i., i i t iu,u"trr. iu*i ir i i ,g' i i t i ,.slopes of the curves.. Higll strength and standard ItwM modar fibres renraln rrrgery withintle. region of the cotton curves.-r-l igh .ro,rjotioii i lrvM nrodal f ibres norvlie between the cotton curves ancl.thit ioi rifon itopfc.. Irr tensile propcrties, the HwM ,n"it. i ' 'r ' iurrr rcscrrrbrc cottorr rr 'rcclosely than does iny otl ier typC "f r.ge".i,,t.a cii lutosic fibrc.

Cour t esy J.D. G riflit tts.

BlettdsThe end uses descr ibcr l .above re late largc ly to yanls rnadc l ionr100 per cent FIWM'rorial fibrcs. lut UWfi-iiroari, "r;;i;;;;;k;;;;rapid he adway as constituerts of yor,r, ,pr,,i-i-;r; ilir;^;i.;;;;."'"

Cotlott Blcnds

The resenrblance of HWM rnoclal l rbres to cott ' ' i .cr icatcs trratll*rg_tyg types of {tbre would lr. .onipoiille i, ble'Js. M;;ii;ithe HWM modal fibre 'ow produced ir'u.ing uscd ir ble'crs withcottor, and many excel lent fabr ics are nraclc- in this *ny, in" i r ' iJ_ing drcss nratcr ials, shcet ings, Iurnishings ctc.

I . I A N D B O O K O F T E X T I L E F I B R E S

l - lWM nrodal f ibres contr ibutc i t tcreascd regular i ty and uni -lorrnity to the blendcd yarrt.

Flax Blcnds

l-lWM modal l lbres ltave higher bending and torsiottal rigidit iesthan e i ther cot ton or rayon staple, and in hbavier deniers theyprovide fabrics with a l inen-like handle. This is especially truein the case of the high strength and standard l{WM modal f ibres.Blended rvith flax, HWM modal f ibres of this type provide fabricsof full l inen handle which is retaitred after repeated washings.

lVool BlendsBlends of I-lWM modal f ibres with wool provide fabrics which

display reduced shr inkage, even wi th the HWM modal const i tuentin cornparat ive ly 5mal l amounts. The handle and appearance ofthe fabrics remain substantially unchanged, resembling the all-wool fabric.

Sytttlrctic Fibre Blends

l-lWM rnodals have reolaced cotton to a considerable extent inlrlencls with polyester f i-bres; thc fabric retains ail thc clesirablecharacteristics of the cotton blend, but is clearcr ancl morcregular . A lso, sucl r b lends of l tWM rnodal and polyester rnay becheaper, as it is not necessary to comb the l-lWM rnodal f ibre;cot ton is conrnronly conrbed before b lending.' l 'he

standard l lWM rnodalshavc a load-extensio l lcurvc which isvery similar to that of polyesters for the first few percentageextcnsion; th is par t of the curve is of greatest i rnpor tance infabric perfonuance. The highelougatiou l-lWM modals have air-drycurves wlrich resenrble the polyester curves over almost thervholc of their range. Blend yarns of dif lerent ratios show amore near ly l inear re lat ionship than do s i rn i lar b lends wi th othertypes of I-IWM modal l ibre, and for this reasorl the high-elongationtype of l{WM rnodal is favoured for polyester blends.

Bleuds of l lWM modal f ibre with a relatively snrall proportiorrof lorv density fibre, e.g. polypropylene, provide fabrics withhandle and shear properties very similar to those of cotton fabrics.The additiou o[ the low dcnsity fibre increases the bulk of thel lWlv l nrodal yarn, which tends to be less bulky and n lore corn-pact than cot ton, largely owing to the c i rcu lar cross-scct ion o[the IlWlvl nrodal I lbre.

t r . I

^ : N A T U R A L P O L Y M E R F I D R E S

cuPRo (CUPRAMMONtUM)

INTIIODUCI'ION

cel lulose wi l l cr issolve in a mixecr sorut io 'o[ c<lppcr sarts ancla nrnr onia, called cuprarnm onium liq uor, on,t ..g.,r.il i..r *ir,,i"rifibres are producecl by extrusion of ttri, solutio]r i,rto o "*g;;;ing bath. -The yarn -procluced

by tlte "up.ornn.,oniunr processconsists of regeneratccl ccllulose; it ir no*'*irt.ty tnoivn'-dil;name of cupro.The cuprammoniurn process hacl i ts beginnings in thc vcrv car lvyears of cellulosic [ibre manufacture. In lg9O, " i+.],.f, .i l#;i

l",l i: lt l lrt Despeissis, <liscovcred that he couict .issotvc;ii;i;;;rn cuprammonium l iquor, ancl spin a f ine I i laurcnt or ,nrt i i i " - i , isilk' from the solution.- Dcspeisiis cticcl, nowcvcr, alrd for twoycars his invcnt ion was forgoitcn.^ln 1892, Max Frernery ancr Johann Urban at oberbructr inCermany made use of the cuprarnmonir,r., pro..r, for rnakingcarbon filanrents used in carly elcctric light bulbs. r' rgca.-'*Jifithc lrclp of others, they bcgan rnanufactu"ring ccilurosic librcs i<rrtcxtilo p_u-rposes; this ' was the bcgin'ing o[ thc VcrcinicicGla.zs toff-Fabrike' A.G., wrricrr u..i,i,. ui. oi tii.-r rrl.r;';,i;;r'ade fibre producing orgarrizations in the *"iia icir"r;;8ii;:C:j.

. Af ter about l0 ycars, . the cupramrnoniunr proccss was aban_doned in favour of-thc viscos" p;";;;r;;;J ir rc.rainecl neglccteclunti l aftcr World War I In 19ll, a tectrniquc of stretch ,p'l; i ; i ;;dcvcloped by J. p. Bernberg A.G. rcvivcJ ini"."rt i ' thc cuprnr'-r 'onium process, ancr sincJ then thc proau"tiou of the nui, i insc.ontinucd.. The cupro fibre has b..o*. wictcly f no*i, o,' lJcntberg' yarn.

NOMENCLATUITE

Fedcral Trade Conunissiotr DcfinitiotrFibre produ.cgd bV thc .cupramrnoniunr proccss is rcgcncratcdccllulose which falls within the class cJescribecl ,,, ,rryl,, ,r i ia.il l te U.S. Fecleral Trade Comrnission <.lcfinit ions, thc ofl icialdcscr ipt ion being as fo l lows:

I I A N D B O O K O F T E X l ' I L E F I D R E S

Rayott. A manufactured fibre corlposed of rcgenerated cellu-lose, as well as rnanufactured l lbres composed of regeneratedcel lu lose in which subst i tuents have replaced not more than 15per cent of the hydrogens of the hydroxyl groups.

Cupro

The term cupro ltas now come into widespread use throughoutthe rvorld to denote any regenerated cellulose fibre produced byIhe cupramnronium process.

C u pr atrtt tto tri uttt Ray o tt

Ctrpro is also sti l l <tescribecl as cupratrrtnotriunt rayotr to dis-tinguish it from viscose rayon.

PI{ODUCTION

In i ts essent ia ls , thc process for making cupro is s int i lar to thatused in nrak ing v iscose. Cel lu losc is d issolved, and the solut ion isforced through holes in a spinneret. The jets of solution arecoagulated, thc cel lu lose being regenerated as a sol id f i lament .

Rarv Mntcrial

Cot ton l in ters and wood pulp are both used as raw nlater ia l inmaking cupro. Cot ton l in ters is a source of very pure cel lu lose,and for this reasou was preferred init ially as raw material.Latterly, holever, rvood pr-rlp has been used otl an increasingscale, largely because of i ts lower cost . For h igh qual i ty produc-t ions, cot ton l in ters cel lu lose is s t i l l used exclus ively .

Cot ton l in ters is pur i f ied by k ier-boi l ing wi th d i lu te caust icsoda at about 150'C. , fo l lowed by b leaching wi th sodiurnhypochlor i te .

Wood is se lccted and pur i f ied to y ie ld a nratcr ia l o f h iehalpha cc l lu lose corr tcnt (abovc 96 pcr cent) . *

Cupranrnroniunr l iq t ror is prcparct l by d issolv ing basic coppcrsulphate in anrnrouia to for t .n a sol t l t io t r o f cupr i tc t rammiuohycl rox ide and cupr i te t ranrmino sulphate in the rat io 3 : l ,conta in ing 3-4 per cent copper and 5-8 per cent ammonia.

* Alnha cel lu lose is that which docs not d issolvc in 17.5-18.0 per centcaust i i soda solut ion af ter 30 nt inutcs at 20"C. I t consis ts of ce l lu loservhich l ras undergone a I r in imum of degradat ion, and i t is t l te mostsatisfactory cellulose for use in fibre-nrantrfacture.

66

Itl}}]-HA : N A T U I T A L P O L Y M I ] I I , F I D R I I S

Prcpr ra t ion o f Sp inn ing So lu l ion

Pur i f ied co t ton l in te rs o r wood pu lp i s rn ixed i ' to cupranrnron iunrl iquor .a . l 1ow tempera ture . S tab i i z ing agcnts and caus t ic socraarc added, the la t ter in suf l lc icnt quint i ty ro "onv" . t

- i i i .

cupr i te t rammino surprrate in to hycrrox i ie . The cc l lu lose .o, r t . , r io f the solut ion is about l0 per cent .The . sp inning solut ion i i f i l terec l by passing i t through asucccssiou of nickel f i l ter scrccns. It i ; t l ,en cllacraf;i i ;;; i ;rcady for ,sp inni 'g . ' l 'hc

solut ion is s tablc aucl r 'ay bc storcdL",i. ::] l-riU:.able

pcriocls wirhour apprcciabt. Acteriorario,,; lnU)rs respect , r t co l l t rasts s t rorrg ly wi th v iscosc solut ion.

Spinning

(a.) Batc lu, isc Spinning (Rec! or pot Spinni r rg)l '^c f i l tercd -spin ' ing. so iut ion i t pun- ,1r . , i ro a u ickcr sp i . r rcrcr ,rrrr l cxtrudccl througrr lrorcs o[ 0.g . iru. rr iarrctcr. ' r ' r t .

i l i* " iso lut ion emerging f rom the spinneret I ro les f low into a g lassfunnel, where thev nleet astreain of purc watc.r which i. i i"; i ;;dow' through tl ie fu'nel. Th" ;Ji;;-. l issoru., .rost oI thcarnmonia and about one third of thc copper fron.r tfr"- j. ir,br inging about coagurat ion of the cel lurose to fornr prast icfi lanrents. The fi laments are carriecl along by th" st;J;;; '-;;water, and are stretchedrcontinuously to fonri nf r",. irt, "i *,,rf i iabou t 1 .4 d tex (1 .3 c l en ) .The loose thread of f i lamcnts erncrging froru the bottonr oftho funnel is carried rouncl a guia."ioir, most of the watcrbeing flung olr. The"thread th.i pass.s iouna a rolrcr rv' iclrrotates in a trough of sulphuric acicl; thc remaining "opp.i""nJanrnronia are removed as copper

'sulphate ancl ammoniunrsulphate respectively.

The f i larnents are thcn wound c i thcr in to skc ins (Rccl Spinrr ing) ,or in to cakcs in a Topham box (pot Sl inni , . Ig ; . '1 l l " ;k" i ; ; ' ; ;cakes are washcd to rcnrovc acicl ancl^ any rcnraining coppcrsulphate or ammonium sulphate, so i t .n .J fy adcl ing lubr icants,and dried. The yarn is.-comnroniy givcn a seconcl *"^rl i l ; ;;3n{ o l t emuls ion, or ( i f i t is to-bJ twiste i larer) i . " ; ; rk l ; ;bath. I t is then dr ied again.

(b) Continuous SpinningAs in the product ion of v iscosc rayon, the procluct ion of cupro

67

I I A N D I ] O O K O F T E X T I L E F I B R E S

has been modi f icd to operate on a cont inuous basis . A cont inuousspinning process was int roduced f i rs t in Gcrnrany and in 1944in the U.S.A. The following dcscription refers essentially to theU.S. process.

Up to the point at which the fi laments emerge frorn tbe funnel,the continuous process is virtually identical with the batchwiseprocess. The thread of f i laments from the funnel is passedthrough an enclosed bath of hot dilute acid called the pretreat-n ler l t pan. This cont inues the coagulat ion of the cel lu lose,reducing the f i lamcnts to about one th i rd of thei r or ig inalc l ianreter . The or iented f i laments of ce l lu lose are sheathed in af i lnr of unal igned cel lu lose, and th is is washed away in the pre-t reatn lent pan. I f le f t , the unal igned cel lu lose would act as aglue, hold ing the f i laments together .

After leaving the pretreatrnent pan, the thread of f i lamentspasses through an ac id t rough where remain ing copper isremoved as copper sulphate. Thc acid is washcd away as the

thread nroves through a water t rough, and lubr icants, s izes etc.are added as requi red by passing the thread over a preparat ionro l l ,

The thread passes through a succession of dr iers and over aro l l which appl ies coning o i l before being wound on to f langelessspools. Untwisted threads may a lso be wound on to beams whichaio used directly in warp knitt ing, or combined to provide aweaver 's beam,

Throughout the cont int rous process, the thread of f i lament isnever ltandled, and irnperfections are thtrs held at a nrinimunr.The l l laments are of h ighly uni lorm st ructure and d i rnensions,and the propert ies are exccl lent . Af ter condi t ion ing for a fewdays at contro l led humic l i ty , the cupro is ready for despatch.

Cupro fi lamcnts adhcre to eaclt other, and are separated onlyby a comparatively strong force. Unlike viscose yarns, they maybe uscd for many purposcs in an untwisted condi t ion.

A rv ide var ic ty o l 'cupro yarns is produced, ranging l rorn l7 toto 330 dtex (15-300 den) and ntore. Weaving and kni t t ing yarns

are cornnlonly in the range 56 to I l0 dtex (50-100 den).

Novelly Yarns

Cupro manufacturers have been particularly successful in theirproctuct ion oI novel ty yarns, such as s lub and nubby yarns.

::,-' FI

68 69

A : N A T T J R A L P O L Y M E R F I B R F , S

1-hcsc may be_ nrade, [or cxarnplc, by cxt ruc l i r rg thc s l l i r rn i r rg: : l : l : i "^r l through

spi .ncrcts wirh two scrs of f r i f iccs. . I .hc f i lar 'c ' rs*o'r one set of orif ices arc alrowecr to cotcct on a flat surfaccto fornr bundles which adhere together; t]r.r, o.. carriecl awayat . i . tcrvals to jo in the f i laments J i t i "J . ,L- i .onr t r rc ot .cr sct oforif ices, forming a composite yn.n *itt, t ir. buncilcs crcating slubsat in tervals .

PI{OCESSING

BlcncLing

Cupro isrcqui rcd.cel lu los icpcroxide.

Scnuring and DcsizingWater soluble s izes, suchtuscd, may be removecl bvat the boil.

an unusual ly whitc f ibrc, and blcnclr i rrg is not gcrrcrul lyI f . i t should prove ncccssary, the usuir l tcclrniqucs forf ibres nray bc uscd, c.g. I rypoclt lor i tc or hydrogcrr

D5'cing

Cupro is a cc l lu los ic f ibre of rc lat ive ly low- crysta l l in i ty (c .g. byconrpar ison wi th cot ton) , ancl i t ; , p .oOr" . . r usual ly in t 'c for ' ro f I ine f i lanrents. Watcr pcnct . " t . , qr l t iy in to thc { ibrc ancldycing takes p lace rapid ly n, ra . f t . . t i i . i r . ' f^" typcs of dycstuf lused for cotton a.rl otrrcr ccrurosic nu"., n.. usca for cupro.' l ' ,c s^ades obrainecr wirrr cupro a;;i;;;;; rrra. trrose obrairc<rtundcr cornparablc concl i t ions 'wi t t i o t t rJ i ' . - " t r r lor i . nUr. r .

STI{UC'I'URE AND PROPERTIES

I;inc S(rucrur" n',u nn[illl-Cupro is the most .s i l k - l i kc 'o [ a l l ce l lu los ic yar r rs . I t i s sn too th_surfaccd and shows 'o rnarkings or r t i i , , t i lnr. l . cross_scct io ' i tis almost round.

The f i larnents are extrelnely-f ine, usual ly 1.4 t l tcx (1.3 dcn),and have been nranufacturecl i , i o.+i hi .*?ol+ ,r . , ,1.

as t l re polyv iny l a lco l ro l typcs of tcnsoaking, fo l lowcd by a ncutra l scour

T I A N D B O O K O F T E X T I L E F I B R E S

COTTON L INTERS(oR wooD PULP)

COAGULATING S K E I N S P I N N I N G ,F ILAMENT YARN

CONTINUOUS SP INNING.F ILAMENT YARN

SPINNING FOR STAPLEF I B R E

LIQUOR

Cupro Florv ChartN A, U

^ : N A T U R A L P O L Y M E R F I D R E S

I'cnsi lc Strenglh

The tenacity o[ cupro is l5-20 cN/tex9 .7-11 .9 cNi tex ( l . l -1 .35 g /den) we i .

The terrsi le strength of Jupro' is about(30,000-40,000 lb/ in2 )

EIongnI ion

Cupro has .an e longat ion o f l0 -17 per centper cent when wet .

(1 .7 -23 g /den) d ry ;

2100-3 150 kg lc rn2

when dry and 17-33

pcr ccnt at d i f lerent

Ulst ic Properl ies

Cupro has an e las t i c recovcry o f 20_7 5c longat ions .

Spcci l lc Gravity

1.54 condit ioned at I I per cent rnoisture.

[ l fcct of Moislurc

cupro swcl ls i ' water and loses st rength. The rnois turc regai r is12.5 per cent under s tandard condi t ions. The cornnrcrc ia l s ta 'c lardi s 1 l pe r cen t .

[ lfcct of l.Icnt

Deco-mposition begins at about 250.C. without ntelt ing. yarnsand fabr ics burn readi ly , leaving l i t t le ash.

Ii l fcct of Agc

Sinr i lar to v iscose.

EIIect of Sunlight

Prolonged exposure causes sotne

Chernicnl I 'ropertics

Acids

l'he fibres are disintegrated byacids.

degradat ion and loss of s t rcngt l r .

1 l

hot d i lu te or co ld conccntrated

I { A N D N O O K O F T E X T I L E F I T ] R E S

Alkalis

Di lu te solut ions do not have any appreciable ef iect . Strongsolut ions cause srvel l ing and degradat ion.

Generul

Cupro behaves general ly l ike other cc l lu los ic f ibres. I t is notaflected by rveak oxidiziug agents or by bleaches such as hypo-chlorite or pcroxide solutions. Strong oxidizing agents cattsedegradat ion.

Eflect of Organic Solvents

Like othcr ce l lu los ic f ibres, general ly insoluble.

-E

cir

U''u'tUx.Fo

o l o 2 a 3 0 4 0srnatru (% rr-oNcattoN)

.::-i :'J=: :-i:::----3: ?j-::::

?.' I r l

I J

A : N A T U R A L P O L Y M N R F I B R I i SI rrse cls

Cupro is rnoderatc ly at tackccl by sonrc insects.

l\ Iicro.organisrns

Wet f ibre is at tacked by nr i ldcws.

Dlcctrical Itropcrtics

It, loderate dielectric strcngth when dry.

Olhcr Propcrlics

The f ibre has a sof t s i rk- r ike handle and a character is t ic rust rc .

CUPRO IN USE

crrpro is in gcncra l n lore expcnsive than other nrnn-nrnr tc cel l r r -losic yarns. Its cxrra f inc'cis.nn,t ; i ; ; i , ; tn, ' t trr ict iv; ' ;r ; l ; :subdued lustre and good tlraping prop.rfi., cnable it to carrvrhis exrra cost in th-c rnanufactul"'oi iiieii q;;l;;; nooir.',,tlVashing, Ironing, Dry Clcaning

cupro is s imi lar to other cel lu los ics in i ts generar berrav iourfowarrfs. laundering ancl ctry cleaning p.o..rr.r. It should bctrcated in t l re same way as v iscose.

End Uses

cupro is made into chi{Ions, satins, nets, ninons a.tl at rnanncrof very sheer fabr ics. _Mucrr

or tn i r -vu i r t goes in to unclcrwear,dress fabrics and linings.

\gvel tV yarns, such as s lub. .yarns, are usecl in a grcat var . ic ty ofapplications, espccialry as weri. strt, yor,rr"r. urJJ ii., ai.rrr^i.*,sportswear and fine drapery fabrics.- A.speciality end use,l. ies in thc production of ynrn_clyccl fabricsfor hig' qualitv sirk-rike Ji,ings, ,ir.rr "n,r "pr.toiri.iy r,ilrl"r.Reel spun ya'ni or. especiaily

*r,iit.a to ttrcse apprications; thcyarc produccd in skcins rcacly for yarn_clycing in the untwistcr lstate. The dyed yarn is used untwi i teA for the welt and twistedfor the waro.


SAPONIFIED CELLULOSE ES'|ER

INTRODUCTION

Dur ing the ear ly 1930s, every ef for t was being n-rade to developtechniques for increasing the tenaci ty of v iscose rayon f i lamentsby motlif ication of the spinning and stretching techniques. Theheart of the problem lay in the d i f l icu l ty of mainta in ing theextruded f i lament in a p last ic condi t ion af ter i t entered thecoagulat ing bath, and so provid ing an opportuni ty of s t retchingthc f i larnent to or ientate the cel lu lose nro lecules (sce page 40) .

Dur ing th is sanre per ioc l , a t ternpts were a lso being made toproduce h igh tenaci ty ce l l t t lose acetate yar l ls by st retchingf i lanrents of ce l lu lose acetate. In th is case, howevcr , the pro jectwas s impl i { icd by the readiness wi th which cel lu lose acetate couldbc brought in to a p last ic condi t io t t a l ter i t had bceu n.radc.

' l 'he haru lcning oI a cc l lu losc acctatc f i larncnt is achicvct l by

evaporat ing solvent f rom the je t of so lut ion ctnerg i t tg f rom thcspinneret . And the l i lament may be reudered p last ic again bytreatrncnt wi th a solvel t t , which wi l l f i rs t swel l and then d issolvethc cel lu lose acetatc. Cel lu lose acetate is a lso a thermoplast icnrater ia l , ancl may be sof tcr ted by hcat ing.

These diflereuces in the behaviour of cellulose and celluloscacetate towards solvents and heat are a consequence of thecl i f ferences in thei r molccular s t r t lc ture. The hycl roxy l groups ofcc l lu losc c lo not encot l rage solut ion of the molecule in organicsolvents, whereas the acety l g f ot lps of the cc l lu lose acetatenrolecule do. Also, cellulose molecules are able to pack closelytogcther and develop porverful forces of attraction associated withhigh crysta l l in i ty ; ce l lu lose acetate Inolect t les, wi th thei r largepenclant groups, do not pcrnt i t o I the c lose packi l rg that resul tsin h igh crysta l l in i ty , ancl cc l l t r lose acct i r te is sof tencd by hcat '

' I 'h is rcadiness wi th which cel lu losc acct l te can be rendcred

plast ic , e i t l ier by solvet t t or by heat , prov idcs an e i rsy solut ionto thc problcm of s t rc tching l i larncnts to create a h igh degrce o[or icntat ion. F i larnents of ce l lu lose acctate which bave beensof tencd by solvent or by hcat tnay be st retched to many t in . rcsthc i r or ig inal length, thc long tnolcct l les of ce l lu lose acetates l ic l ing readi ly ovcr onc anot l ter as thcy are drawn into a l ign-Incn t .

74 75

^ : N A - I . U R A L I ' O L Y l ! { E , I I I r I I } I ( D S

,Dur ing t l . re car ly 1930s, - the st retching oI so lvent_plast ic iscc l

cc l lu lose acetate resul tecr i ' . t r re ' rocruct ion of varr rs wi t l i , . , , i i " i i i . . . ,i ' tne regio. of 44-53 cN/tex (5-6 g/dc'). ' l i i . i . y;;;;;; i ; i ,;; i it l rc essent ia l character is t ics o i cc l lu losc acct^ tc , but thcy courcrbc converted in to cel lu lose by sapo' i f icat ior wi t r r caust ic sodasolut ion, prov id ing h ighly-o i ientec l f i laurcrr ts oI rcgcncratcc lcc l lu lose. ' fhc rnolec ' res i ' thcse sapo' i f iccr cc i lu losc acctr tcf i lar 'cnts werc in a r lore h igrr ly or ie ' iccr a 'cr crysta i l i rc co 'd i -t ion t ,a . could be obta inecl t y s t retchi 'g I i lar ic ' ts proAi i . .Adur ing coagulat . ion of v iscose ,oyon.

1- l ] r r e lega' t tcch. iquc of crcat i r rg l r igr r ly-or icr r tcd cc l lu l 'se f i ra-'e'ts lbrrns rhe basis of .trrc pruc.r"t usccr by tl,. b,,iiitr"ii,group of cornpa'ies in proirucirg higrr tcrLacity'rryo,,r-,i,iaii iri.t r ade na rne 'Fo r t i san ' .

NOMI]NCLATUITE

llul,onIr ibres produced by the saponi f icat ion of cc i lu losc acct . tcare rcgenerated cel Iu lose, an<l are proper ly dcscr ibecl asundcr the rules of thc U.S. Fccleral t l.r,r. l"

Co,ll,tr issiou (sccxxvi ) .

I ' I {ODUCTION

fi brcsrayotl

p i rSc

l:::: l tt:.cJ cellr.rlosc accrittc f ibres arc nraclc by hcatirrg ccllulosc

liil'i;i,'ll,']?' l,I^..:r:,'l:. : ::'ii'l -i r, b", i t r. k;[;;; i : 0 i;);;:),;::1,;,..llli'lq llT sofrcne<l. vnr,, rry.-+'t" lo "iiiu.,

iir" l?iiil,,iilength. Tho stretchect yarn ii wouni on roili;;;,;,i ;;t1;;;and. saponi f ied by t reatrnent wi t r r caust ic socr* so lut io . . I ' t rc yar 'is thcn washed, oitccl, driccl nn.t ,"*oi,n.i. -

Vcry f ine f i lanrcnts.of rcgencratcc l h ighly_or icntcdnray be produccd in thrs way.

PI IOCESSING

l)yeing

Sapo' i f ied cc l lu losc acetatc yar ,s r ravc ayci r rg propcr t ics s i ' r i lurto those of cot ton or v iscosc rayon, thc i r igh, i .g . .c of or icnta-t ion rendcr ing dyeing s lowcr and lcss cf fcc ' i ivc.

cc l I u l osc

I I A N D B O O K O F T E X T I L E

S'TRUCTURE AND PROPERTIES

F I B R E S

Saponified cellulose acetate yarns consist of regeneratecl cellulose,and their characteristics are esseutialty those of highly-orientedcellulosic fibres. They are sirnilar to high tenacity yarns clerivedby the v iscose and thc cupro tcchniqucs (sce pagc 43) .

The mechanical prope rties of the yarns depend upon thedegree to which the fi lanrents have been stretched.The prop.crties describcd i^ t lre following section are based upo'' l lor t isan ' .

Finc Structurc and Appcarance

Filaments are of somewhat lobecl, almost rouncl cross_section.The indentations are seen as striations when the l i lament is view.Jlengthwise.

Tensile Strcngtb

Terrac i ty : 53.62 cN/ tex (6-7 g lden) dry;44_53 cN/tex (5_6 e lden) wet .Tensi le s t rength: 9520_kg/cnr2 1 l :6,000 lb/ in2) .Loop st rength: about 50 per cent ofs tandard.

'

I i longation

6 per cent, dry or wet.

Ma.stic I lecovery

60-80 per cent at 2 per cent extension.

I r r i ( ia l Modulus1 500-2207 cN/tex ( I 70-250 e/clen).

Avcragc Stil lness

1 0 3 3 - l 1 9 2 c N / t e x ( l l 7 - 1 3 5 g / d e n ) .

Specific Gravity

1 . 5 .

* ' lJ ' , l_r L'L" I

76 77

N A T U R A L P O L Y M E , R F I I } R B S

Ii l lcct of Moislurc

I'I igh rcsistance to stretch is retainccl un<ler both wet andcondi t ions, g iv ing h igh d i rncnsional s tabi l i ty .I(cgain : 10.7.

Olhcr Propcrties

Sinrilar to cotton ancl viscose.

SAPONIFIED CELLULOSE ESTER FIBI{I]S IN US[]

d ry

.Saponificd cellulose acetate yarns are used for applications typicrrlof high srrengrrr ceilurosic rayons rr." liigrr'rtr.neil,-;iJ""*r^yo'rs, page 46). They are ,scd whcrc a high rario ii ,r;;;;ii;t<l volur'c nnd cxccl lcrrt. crir.c^sio' i , t ,rni i i i ry 'rc ncrvnrrr 'gcous,c.g, in parachute roncs and_fabrics, tyr.'.or,ts, bclting, i;;r.i-;;r;ibal loon fabr ics. T l re very f ine f i lamcnts ,nn, t . by th is tcc l rn iqrrc'ave. enabled saponificct iellulose ;..1;i; yarns to rc1:lacc naturalsilk in applications such as elcctrical i 's,ir"i i",, "- '" i ' . ;;[, ;.;: ' ;;;hearing. aid equiprnent. Coatecl fabrics provide l ight, strongtarpaul ins and protect ive fabr ics.

|}}}}


78 79


2. CELLULOSE DSTER trIBITES

I I A N D R O O K O F T E X T I L E F I B R E S

CELLULOSE, ACE,TATE FIB[{'ES (ACETATE,)

INTI{ODUCTION

viscose and cuprarnmoniunr rayons are basically similar, in that

the l ibre procluiecl at the end of the process consists of cellulose.

In both pro" . t t . t , the raw nrater ia l ce l lu losc - wood ptr lp or

cot ton l i r i ters - is brought to a soluble fornr so that i t can be

extrudecl through fine holcs to form fi lanrcnts. The fi l irment is

created by regcnerat ion of the sol id cc l lu lose as the l iqu id je t

enters the coagulat ing bath.Viscosc and cuprammonium are therefore regenerated cellu-

lose. In their chenrical structure they resemble cotton or f lax'

But thcre is anothcr important [orrn oI cc l lu los ic man-made

f ibrc, i t r which the wood or cot ton cc l lu losc is c l tangccl in to a

di{Ierent substance to render it soluble ancl spinnable, ancl after

being spun is left in its changed chemical form' This fibre is

made fionr a chemical derivative of cellulose; cellulose acctate.

Like the nitrocellulose ft 'om which early rayons were spun'

cel lu lose acetate has bulky groups of atoms at tached to the long

cellulose molecule at intcrvals throughout its length. These acetategroups tencl to keep the molecules apart, preventing the alignment

incl 'close

packing into regions of regularity which make for

crystall ine siructure. The hydroxyl groups which exert so powerful

an attraction on each other' in thc cellulose nrolecule have been

reclucecl or elintinated, dirninishing the grip exerted by eacll

molecule on its neighbotrrs. It is easier for the molecules of an

organic solvent to penetr r te between the molecules of ce l lu lose

o""tot. than betwecn the molecules of cellulose itself, and

cel lu lose acetate tv i l l d issolve in sui table solvents.The n i t ro groups in n i t rocel lu lose had the d isadvantage of

n.raking the niaterial highly flartrrnable. But ccllulosc acetate is

no nrore f lunntable that l cot tot r .

Cellulose acetate was first prepared by Sclrutzenberger in 1865,

by heat ing cot ton wi th acet ic anhydr ide at 130-140"C. in a c losed

vessel. In 1894, Cross ancl Bevatl discovered a more practical

process, in which thc acety lat ion was carr ied ot l t a t at t lospher icpr .ssurc, us ing sulphur ic ac id or z inc chlor ide as cata lyst '

80

- t 'lt.. l l

h ,

' ,1

' l

; l, fI

I

fI: lr l' l

i l1 l;i,

I, ltl

iTflfr. t

I

f

il

IL{t

{J

' l i

lr{ ,l :. t '

l il lli

l !

i i4,t]$iirlit iRli l

a i

i ,tcl rl lFl .l 'IltI1 1i :l!, !

IL

tt'

A : N A T I ' R A L P O L Y M E R F I D R I ] S

Prinrory Ace!ate-flrc

cellulose acetati: producccl in these carry cxperiments wasn conrpletely acetylated cellulose, i ' wrrich ntt t i.tr.. irvJr"*vigroups of each g lucose uni t i ' the cc l lu losc molcculc i , n . . iyLni . , t .I t was cel lu lose t r iacctate, whicrr ratcr bccar 'c know. u, 1r i i , * rylcctate (scc page 82) .

cel lu lose t r iacetatc w^s obta inecr as a tough, horny sor ic . r rvh ic l rrvas. no.t readily wasrrccr frce of acid, an<I it arso containcJsulphur ic ester groups which rcnclcrcc l i i unstablc. I t was solubleonly in tox ic a 'd expc^sivc solvcnts, sucl r as crr lorofornr andt c t rachloroethanc.

Secotrdary AcelaleIn 1906, Miles discovercd that the triacctatc courd bc partiailyhydrolysed to produce a cellulose acetatc in whicr*on.," oi tt,Lncctate groups of thc triacetatc had bccn ren.rovcd, nnct rccon-vcr tcc l to hydroxyl gro,ps rs in thc or ig i r rn l cc l l r r losc. l l , i . , ; ;t 'atcrial was, in eflcc.t, a partialry acctyratcd cciltrrosc urrtrri".,rby cornpletc acetylation

.ancl subscqucnt partial fry<lrolvrir. l tbccanre known as ,secondary

acctatc;.The sccondary acetate was soluble in a rc l t t ivc ly chcap and

non'.toxic solvent, acetone. Also, it courcr be wrstrccl frce oi acidnruch nrore easily than the primary acetatc.

Dur ing the per iod leacl ing up to ihe outbrcak of Wor lc l War I ,nrany w-orkers exper imented wi th thc procruct ion of ce l ruroscacetate fi laments from solutions of the prirnary ancl sccondaryacctatcs. The secondary acetate, which dlssolu.i l i ,, thc chctpciand less toxic solvent, appeared to olTer thc greatcst prospcct o[success, and it was upou this material that lnuch oi ttr. *ortwas carr ied out .

Anrong the most active workcrs in the cclrulose acctatc ficrdat that t inre were the brothers Drs. Henry and carnil le Drcyfusi ' Swi tzer land' when war broke out in 1914, the brot i rersDreyfus were inv i ted to Br i ta in by the covcr 'nre ' t , who wcrci . terestcd i ' the usc of cc l l r r losc acctarc as a varn ish for thcfabric wings of aircraft. In the early tlays of thc war, nitro_cellulose had been used for this purpose, iut its extrcnrc fla^.r-nrabil ity had causcd heavy casualties. cellulosc acctatc was r'uchmore satisfactory for the purpose.

The Dreyfus brothers establislrcd a ccllulose acctatc factoryat Spondon, Derby, where secondary acetatc solut ion or .donc,

8 l

I

-.----------.-----_---.---------


H o c o c H 3

.\^,/:;i,\.1 *..,r'\3_ o,/"\o.z-

lH.o.o.t ,

cHzococH3

'-o\ . /o\---

\i:atl'\ A.ocH,

CELLULOSE TRIACETATE(entuaRY AcETATE ; FULLY acrtvuetro)

CELLULOSE NCE,TATE

:lrrlrl.:gl'.iliiii{i::Jfiiilxri!tii:if th9::i''-"'**fl':^{H*iiiti'fi :$ti:j'* :*mf ii|i,{tlji:h':ij *r;;; . n o n,.,r, v,. n.chiorictc'

-lt is insolub'"r,';ri11:11?al

'vdrolvsis o[ cellulose triacctatc

l5'"'"tfff 'r"9il"i?'t',f ';.; tii" g,o,, pr . back i n to

-ii v<lroxvl sr ou ps, to

;;;i l ' ; .;;;;;v-i"riuror" i. i tft". t i t ' i t is. sonretimes called cellulose

.iacerarc, implying tr.,oi". i i fr 'Jiu..oi"-unii tt is trvo of its hydroxvl

[l*T;.*;:rWltfl n"l'fi*;l*.,";:Jl"i.3lr""i'3i"''""'"':iii'lll'tcel lu lose acetate.'"i l ;;;;;;rt

iellulose acetatc is soluble in acetone'

4'E::"1"{r?!"3,:i::I3:i"" of the celIuIose.molecule.,iir'il]}t:::,i"'"i:l:is".onif ionfv cxprcssecl as the acely/ valt le' u

'"8ii?l'3j1,"1ifl,qq1 i"1,,,,,,,,,,,,,''1;:"1i,?".it' l^.111"..:1..6^2;5, ffi:;;'it:;!lmerciar

,..-t t , f ^.v t . t lulose acetate has arl acetyl value t

rvas ultinratcly producccl ir"r considcrable quantity' When Anrerica

cntered the rvar , Cami l le Drcyf t rs went . to the U'S ' to establ ish

nrocluct ion of ce l lu losc acctatc there ' Thc war ended bcfore thc

i ; ; ; ; ; ; t conrpleted ancl Drcyfus returned to England'

Aceta le F ibres- fhc cnd of thc rvar fot tnc l the Dreyfus brothers wi th a largc

. . iLutor" acetatc facto iy i ' l l r i ta i r l , i ind no longcr nt ry c lc t ' i t t td

io, n i i . rn t t dope. ' l 'hey 'sct to work; therefore ' to t ry and dcvelop

82

A : N A ' f U R A L I ' O L Y M I ] I I F I B I T E S

a cel lu lose acctate f ibre. By r921, nrost of the tcchnicat <t i f i icu l t ics1"9 P."1 overcome,

.ancl a fi lament yorn- *n, being nraclc irrI lr itain fronr seconcrary ccllurose -aceraic,

u.crcr t^c na'lc'Cclanesc ' . Sorne s ix years la ter , Courtaui .s Ltd. , , " ; r " " ; i ; ;producing a secondary cei lurose acetate yarn. In r934, a rn i l l ionpound*s

.of _acetate yarn. was exporte<I to Arnerica, ,,;. i ;t i j ; i ;y.ear Brit ish dyestu[s chenrists iracr sorvecl trrc biggcst pi"rri. i , ilhat .was hold ing up r 'e progrcss of thc ncw nUrc _ i iow t ; ' ; ; ; ; ; .

Viscose and_,cuprammonium rayons, consisting n, tfr.V ;; ; iregeneratcd cellulose, can be dyed with dycstulls usccl foi cottonand other natural cellulosic fibres. cellulose acetatc, howcvcr,clif lers chernically frorn cotton in trrat marry of ttre trvaroiyi:l::1,^:. ^1,1y: -b:""n.,r.ol"cd b.y. acetate sroups, an<l rhe

-a{Iini iycnaracrerrstrcs oI the fibre with respect to clycstufls have bceirchanged. It was necessary to deveiop new typcs of dyes foracetate l ibre.

O.ncc t l r is problcrn l rac l bcen.solvcc l , cc l l r r loscrr radc rapid hcadway. l : j lanrcnt yarns, s t r ip lc nndprod.uced in rnany countr ies, on, i or" 'avai iable inof sizes and spun-dyecl colours. They are nowas ecetatc (see bclow).

NOMENCLATURE

Acelal c

Until conrparatively recc'r t i 'rcs, f ibrcs spun lro.r scc<l'darvcc l lu losc acetate (see page g2) wcre crescr ibccr nr- : * . t ,u"- r "J" , r lIn modern terminology, .rayon' is uscd o,rry i,i a.r".i;;;;'iib;;;consisting

_of regcnerat"., l c.l lulos", inclucling viscosc ,oy;; ;;;cupro ' and f ibres spun f ronr secondary cc i lu iosc accratc; r . , i ; ;known sirnply as ocetale. Iribres spun fro,n prinrary cclluloseacetate are called triacetate.

I,'eclcral T'rade Cornttissiorr DefinitiotrT'he generic LcrtTrs acc!arc irncl trictccrurc wcre arloptcd by thcU.S. Federal Trade commission for f ibrcs o[ trre ccllrros. ^..tni.typc, the ofi icial dcfinit ion bcing as follows:

Acetate (and Triacetatc). A manufacturcd fibre inf ibre- forming substancc is ce l lu lose acetatc. Whcrc not92 pcr ccnt o[ the hydroxyl groups arc accty latcd,

ncctntc f lbrcstow arc norva widc rangc

known sinrply

which t l rclcss thanthc ternrf ibre.

' t r iacetatc ' may bc usccl as a gen.rn i c lcscr ipt ion of thc

83

I I A N D B O O K

t , t toDUC' l ' l oN

O I : ' I ' E X ' I ' I L E I : I 8 I { E S

(A) lcarvl,r,'noN oF wooD put-p ol( colroN LINT.ERS

Itatv IVlatcrial

As in the product ion of v iscosc rayon a.c l cupro, the cel lu losetused as rarv mater iaI in acetate manufacture comes c i ther f ronrcot to l l l in ters or predorninant ly f ronr pur i f ied wood pulp.

Cot tot r l in ters are pur i f ied b) , k ier-boi l ing for seveia l hoursrv i th a solut ion o[ socl iunr carbonate or caust ic soda. The l in tersare thcn rvashed and b lcachccl wi th sodium hyl rochlor i te , washeclaga in and d r i cd .

Slccpi r rg

1 'he pur i l ied cot ton l in ters or woocl pulp are steepcd i . g lac ia lacct ic ac ic l to swel l the l lbrcs ancl incrcnsc thc i r chemicalreact iv i ty . Modcrn proccsscs usc vapour-phasc lc t ivat iou bnsccl orracet ic-wa ter nr ix turcs.Accly l l t ion- l 'he

swol len cel lu lose is t ransferrcd to a c losed rcacr . ion vesselconta in ing a nr ix ture of acct ic ac id and anhycl r ide. l 'he rn ix turehas the fo l lowing weight rat io :

Pur i f icd l in ters I par tAcet ic anhydr ide 3 par tsClac ia l acet ic ac id 5 par ts

The rcactants are nr ixcd, ancl a smal l quant i ty (0.1 par t ) o fsulphur ic ac id d issolved in g lac ia l acet ic ac id is aOaed. . |heaccty lat ion of the cel lu lose now procecds. The react ion isexotherrn ic , and the vessel is cooled to mainta in a predetermineclternperature prof i le . Af ter a per iod the temperatur i is a l lowed tor ise a.d mai ' ta ined at a h igher ter 'perature ior a fur ther per iod.

Dur ing th is t in te, conrplc te acety lat ion of the cel lu lose takesplacc. The thrce hydroxyl groups on cacrr g lucose u ' i t o f theccl l r r losc nro lccule are : r l l accty latcc l , and thc l r roctuct is cc l lu losctr iacetate. ' fh is

is known as pr inrary acetate.

Ilydrolysis (It ipcning)

l 'hc sol r r t ion of pr i rnary acctate is t rans[errec l to anothcr vesscl ,a 'd ' r ixed wi th d i lu te acct ic ac id. The res ic lual acet ic a 'hydr ic lereacts rv i th the water to [ornr acet ic ac ic l and th is , together * i i r i i r r .

84

U t , U L

N A I - U R A L l , o L Y M S t { r r t t } l t I s

rcs iduar .cct ic ac id f ronr thc acetyrat ion ' r ix turc, lor r r rs a sorut io 'o f acct ic ac ic l in watcr .T 'e cetu lose t r iac^cr 'a tc is a 'owcd to s tand i . t , is sorut ion o[acet ic ac id in water f .or . t rp to ZO torr r . bur i , ,g th is t inrc, par t i i r l^ydrolysis of the cc'ulose i. i^..-tnt"' i . i"s pr".", sonrc of thcacety l groups beinsi L" J' r iv j, "i ;,;,"' :i, ;:"',: :' i, " :f J:', :.J - il i,1 f i'.: j:il ;, ;lr,lll :

;l3lll ::L ̂ t,.ol..rr: r hc cornplcr.r / n."ivil r.rt ccllu tosc r riaccrl rcDcrr lg converted in to a par t ia l ly-acety latca cel ru lose ^ . " t , i i " . - - " "' I^e restorat ion of somc of . t l ic hyc l ro^Vt g.oup, o ' t l te cc l l r r loscocctate rnoleculc c ,anges

. the soiubi l i ry .1 ,u.^ . t . . i ; i i ; r ' ; ; . . ; , "acet:rtc. ce'urose triacetate is sorublo in Jrrrorofo.ii, 'rr,,il,,J"r,,iri"

i ' accrone; the part ialry-o".tytni.a'1; ir; i ;r . accrate is irrsorubrcin _chloroform, but so lu-b le in 'n . . to , . , . . " " ' '1'he partiallv-acetylate<l cellulose

-acetatc nradc in t ' is wav iso f t cn ca l l ed . . l l u l o r ,

l:i:l ,l:;,i ;;;;;' 'i,li".''';::;,,''i:ili,illf,,""1l,,i,";,,lliiilJii'i:lrr ;rcctatc, so that cach glucosc unit now lras two <l i l , ; i i ; , : ; ;hydroxyl grorps ac"tytat i<I . 1, i , ,1,r"r"" , ' t 'e scco'cfary acctatcused in spinning acctatc f ibre ao.r nor .J.rcspo.a prcciscry witrrcelluloso diacetate. fhe hycrrolyri, "iir* i.racctatc is arowccr toproceed unt i l each glucosc uni i in thc cel l i r losc ; ;"r . ." i .1," . i ""average, about 2| of its hy<lroxyl groups u""tytot.a n* ;;.;;;1.;;acetate structure lies part way Letwecn t'at "i i;i*;;;;.;;rid iacetate.

Dur ing the hvdrolvs is process, tcsts arc carr ic t r out at in tcrvarsto i'clicate how the' ,r.-L..ivi"ii"u'ir'p"r*..,rirrg. wrrc. it lr.s:."r:T9 the desirect point,.tlic ,oiuiio,, i."porr.A into a' cxccssot water, arrd the scco'dary acetatc is prccipitat., l ;; ; lr; i ;f lakes. ' l 'ese

are was'ecl t6r;; i l t ona ,rrry be grourrcl i ' tof iner par t ic les.The acetic acicl is rccoverccl from the residual solution antlused again.

I)ry Spinrring

Thc spin ' ing solut io ' is ma<Je f ror ' a b lencl of sccondary accratcconta i r ing mater ia l f ronr a torg. nunrL"r-o i batc l rc .s , i . oracr1o : . :u . : as h igh degree of uni i 'orn i ty as 'possiUlc. T 'e b lcndcdacetate is d issolvcc l in

.acctone conta i r i i r rg i - sr r rn l l propor t ion oIwatcr (up to 5 per ccnt on the wcight of"acctorrc) , ancl p igrncntst t tay be addcd at th is s tage. Rinely-_div iJc, l corbon b lack (2 pcr

85

I ' T A N D D O O K O F T E X T I L E F I B R E S

ccnt on the weight of acetate) is used in rnaking black fibre;

t i tan ium diox ide 1t -Z p. . cent on the weight of acetate) is added

in making dul l l ibre.The spltning solution, now known as 'dope', is f i l tercd carc-

fully and deaeiated, ancl is ready for spinning' It contains 20-30

per"cent ccllulose acetate. It is pumped to the spinnerot' under-

i ioing n nnul f i l tration on the way. From the spinneret holes, jets

6i tt i inning solution, 25-15 p in cliatnetcr, cmerge into a spinning

iuU.. ffr ir-i, an enclosecl vessel through which hot air is l lowing

ni n t.,"p.roture of about 100'C. As the jets of spinning solution

ntcet the hot air stream, acetone is evaporated to leave solid

f i larncnts of ce l lu lose acetate. More than 90 per cent of the

acetone in tlte jets is evaporated during the fraction of a second

that the jet is moving downwarcls through the spinning tube'.

ifr" nlwly-forme,l f i lurn.nt of cellulose acetate is stretched

,f igfri iy wtrite stitt plastic, to align the long molectrles a'd develop

the st rength o[ the l l lamcnt .Af ter

-moving <lownwards through the spinning tube for . a

distance of sevJral feet, the fi laments are sprayed or wiped with

lubricant. Thcy pass round a guide roller and emerge from the

spinning tube on to a constant speed feed ro l l ' From th is ' thcy

nie leaio a winding mechanism which may wind the untwisted

fi laments on to a cylindrical tube, or insert twist and then

*i, ia tn. trvisted yurn on to bobbins' Ring mechanisms arrd cheese

col lect ion are cotnnlonlY used'Acetate ft lament yains procluce<l in this way are ready for

immediate use, without any of the washing or puril ication treat-

n.rents that are necessary with wet-spun fibres'

it l" technique of dry spinning is made possible by the fact

that seconclary cellulose n".tut" dissolves in a readily-evaporated

. o t u . n t ' a c e t o n e . T h e p r o c e s s i s s i m p l e r a n d f a s t e r t l - r a n t h e w e tspinning processes usecl with viscose and cuprammoniurn iuygl!or iJ tp inning may be carr ied out at very,h igh speeds of 1000

i i i . l r . i per r r i inute. There is no handl ing of t l te f i larner t t between

extrus ion and col lect ior t .Acetate fi larnents are procluced in a range of co.unts, the nlost

ooor tut f i larnents beingô[ 3.3-4.4 dtex (3-4 den) wi t l t yarn

coi r r r ts 44-2OOOdtex (40-1800 den). The cout t t is contro l led Dy

i t i i . . - fn . tors,

( l ) t5c ia te at w6ic5 spi ' . i 'g so lu. t ior t is .punrped

to the spi r tneret , (2) the s ize of t l le sp i r tneret l to lcs, and (J) t l le

rate at wl't iclt t l te f i larnent is drawn away from tlte spinneret'

8 687

A : N A T U R A L I ' O L Y M E R F I B R I ] S

Staple f ibre is produccd by cr i rnping theO u l e n C l t f l r n s l l r c m i r r r n c h ^ . r t ^ - ^ , r - .a|d jlr,gn gytliie^. rhem inro ,rrori r.ijiii,

l i lar r rcnts nrcchanical lvranging f ront 38- l50to b l cnd su i t ab l y w i t h

dnu rncn curung u lem l t l to shor t lene thsr r rn r ( l t l -6 in ) . The s tap le length is ch isenother. f ibres in lnaking blencleriyarns.

1l*::1.:!e.<lry ipinning

^process sirnpli{ics thc producrion:j jl..l",:_ fi qT 1 jI,," n F:r rs"

-of 'o " r,!r. ; Ji^;r',..i""rr"*j,i ;;':;'Jneeded in considerable'ccucu rn couslc lerable^ quant i ty . Every kg o i accta ic f ib ieproduced needs about O.e S ts of .o t ] , , i " . " I s lz . n f , ,^^r i^kg of _cel lulose, 1.5 kg of acet ic

Iillili:; 1;9, It lf.:::'*t''q'ô$ k;;a;ipi';i;:.ij, j d 'l;:::,T:"':?.111.1: ,*1.,, f Io gari; oiwa"tJr. Triffi,#;lll,;i.,l,iiduction of acerare fibrc is nl.,ri" porriut; ;;lr";;',i;;";J;;,recovery of a. high proportion of thcse raw rnatcrials, so that ri icfcan bc recvcled.

lVet Spinning

The. f ina l s tage in the pro<luct ion of seconcrary cc l ru losc acct . tc:,:'::1'l: :::^:*'ltf i'l*'' 9t qLi"iv .".i;i; i,iliil;;';";J"i;l,::ll.l::li1lcid 'Lrct.wnrcr.'.t.r,. ,..oii,i^ry ,.1t,,i."i, ,',i,,1:,J;as a solut io ' , f rom which. i t is prccipi tated bycr i lut io ' * i t r , * ; t . . lIn the n9r3al way, this precipitation is*Jarri.a out i. such irIil"i.:":l l.l1Lll.: of secondaiy n .tut. Jii.i, *. J,ir,r.o"er,,ri:i:'^yl::.1 .,: . l:,.ron" for <try rpi;,,;i;;. ;,;';;;;' ;r";; ",ffffi:ill:::'::": "t "^ I ll j : o,':' :q " " ; ir"'' ol u't i Jn ;i ; ;i; ; ; ; i I il" ;l:lli[r"l':Y:,:. ::-uld . b: ex tr u d e d. il,;;Gh ; rrr",*.* i ;;iJ' iii:" J,ll]lose acetate precipitatecl in tê forri oi n' ionr.nt, in au aqucouscoagulat ing bath.

Wet spinning techniqucs of this sort have becn clcvcloped forspinning cel lu lose acetate.

Il lclt Spinniug

Cellulose acetate is a thermoplastic f ibrc; it nrclts when hcatcdto temperatures in the -region of 230"C., ancl molten-;;. i;; ' ;sull iciently stablc to undergo -.ft ,pinn-G.wi t , t 'c dcvelormcnt o inrc l t sp i i rn i i r l icchniqu.s for sy ' t l rc t icl ibres. , the ' re l t ip inni 'g or . . i r r ior . '^ . . t " t " has beconrc apractical possibil i ty, and- many ";;;; i ,r,;;;.1 fibres havc bccn

ll," I ;.I|1, llll. "l'_ j iq., i n s.om e ui"v, ir*, n i^..",r' o."a "iiliby dry spinning, notably in thei r react lu r u rJ rp r r r ru8 , noraDly ln u te l r reac t ion to bo i l ing watc r . Dryspun f i lamcnts tenc l to rJerus t re in bo i r ing water , bu t ' rc r t spunIt I ame n ts do n o t. rh. ; ;;i;;'" r "'.ii,o "i, nriii;,,ir'i, "'ffi iJlilncl t spt rn

I I A N D D O O K O F T E X l ' I L E F I B R E S

Acetale Flotv Chart

8 8

WOOD PULP ORCOTION L INTERs

ACTIVATEDCELLULOSE

ACETYLATEDCELLULOSE

TACETIC ANHYDRIDE

SULPI IUR IC ACID

PROPYLENEgas

rffiq. - T ]

l r. .or.ry and rc-usc-

wa ih i nq . A .watcr->dr i inq ->wcak acct ic acid

- acctonc cxhaust to recovery and rc-use i+ - - - - - - - - - - - - - i

*ob td inab lc f rom e i thcr ace t ic ac id o r acc tonc

warm air ->

r-------I

*

:CONTINUOUS

FII-AMENT YARN

L]

^ : N A T U R A L P O L Y M E , R F I I l I T E SI\lodil iqrtion of Filnnrent

I* conr'ron with other. rnan-made fibres, cellurose acctatc fibrcsnray be produced in physically_modified fornrs by ,r,oniputniio,,of the spinning process.

Spun-dyed acetate l ibres are now bcing nradc in great varictybv the addition of pigments.to the spilning sorutlon p.i"i- i6extrus ion. carbon b lack prov icres b lac i f ibres; t i tan ium'd iox idcis used to modify lustre.

",I11.^.:.r^" of spinneret orif ices of appropriatc slrapcs rvil l proclucc

alar l rc ' ts or unusual cross-sect iors, and rna 'y var iat iu i rs w.rcnrade commercially. Frat f iraments rcflcct tnc tigtrt ana yi. iJnovelty glitter yarns. X- ancr y-shaped cross-sectioniprovi.t" y'orrxof improved handle ancl.covering-power, nna yornr'*ir i;f ;;;;;in water. Thick and thin yarnJ and siub yarns are nrade byvarying the rate of feed of the solution to tl ie spinn.;. i; ;;; ; i ,thc extrusion of dif lercnt f i lanrcnts which ,"" ,,,frr.qi,.,rtf ico lnbincd in to cornposi tc novcl ty yarns.

(B) lcnrvrnrtoN oF cr:rrul.ostc FIDRE5In . the product ion of ce l lu losc acctate f ibres by thc norrnaltcchnique, the raw material is ceilulose in a fibrous form trrutis not, however, suitable for texti le use. Cotton rinters ;;. i ;;shor t to be spun into a sat is factory yarn; woocl ce l lu lose iscontaminated wi th natura l gums and res ins, and the f ibrcs inpuri{ied wood pulp ^r" ugain too short to fbrrn u t."t l i ;-;;r;;:During.acetylation, the fibrous structurc o[ the ccllulosic'rawmaterial

. is- destroyed; the acetylatecl cellulose forms a solutionfrom which cellulose acetate is precipitated as flakcs; trrc nakesare redissolved and spun .into fi lamenis.

It has long been known that cellulose fibres may unclcrgochemical modil ication without losing thcir f ibrous f"orm. If"acellulosic texti le f ibre is acetyrated un*crpr sucrr "onaitions, lt -ovbe converted in to a f ibre which is e i ther cc l lu lose t r iacctatc or a 'i ' t inrate rn ix ture of ce l lu losc t r iacetar .e and cc l lu losc ard is in astate sui table for i rnrnediate text i le usc.Cotton

Cot ton f ibres of text i le qual i t .y- may bc accty lntc<l wi thout los i r rgi l re i r . f ibrous fornr , the modincd hbrcs bc i , rg cc l lu lose acctatc.Practical processes for the production of acclyrated cotto. lravc

I I A N D D O O K O I : T E X T I L E F I B R E S

been establ ished by the U.S' Departmeut of Agr icu l ture, us ingei thcr a batchwise or cont iuuotrs technique.

Batchwise Proccss. Cotton fibrc, yartr or fabric is purif icd by

boi l ing in d i lu te caust ic soda,washed_ and d: ied. l t is then a l lowed

to soik in acetic acid for at least I hour. Excess acid is squeezed

from the cotton, which is then treated with a mixture of acetic

acid ancl acet ic anhycl r ide in the presence of a snra l l amount ofperclrloric acicl catalyst. After treatment for I hour at 20"C''

the cot ton is washed and dr ied.

Continuous Process, Tltis process, rvhich is designed for ttsewith fabr.ic, is essentially the satne as the above, but presoaking

is shor tenecl by carry ing i t out at 82 'C' for 2 minutes. The

fabric is coolecl an<l passed coutinuously through a bath ofperchloric acicl in acetic acid, followed by treatment with acetic

inhydr ide in an acety lat ion vessel for 3 minutes at 20"C' Thecot ton is then washed and dr ied.

Part ia l ty acety latcd cot ton procluced in th is way has great ly

improvecl rot- and lteat-resistttnce (see PA cotton, Vol. l).

Viscose

Dur ing the 1950s, Japanese sc ic t t t is ts developed a s imi lar process

for the d i rect acety lat ion of v iscose f ibre wi thout destroy ing i ts

fibrous form. This technique has uow become the basis of aconrmercial process rvhich produces a cellulose acetate fibrer l i rcct f ronr a polynosic- typc v iscose by d i rect accty lat ion of thei ibrc. l " ibrcs carr icd t l rc t radc r la tncs 'A lot t ' or " l 'o l ta lo l l "

The acety lat ion is carr ied out by soaking polynosic rayonstaple in a solut ion of a cata lyst (e.g. sodium acetate, z incsulphate) , par t ia l ly dry ing thc f ibre and then passi t lg i t through achanrber conta in ing acct ic ac id vapour at I l0 'C.

' fhe f ibre then

passcs through an acetylating chamber containing aceticanhydr ide Yapour at 130"C.

Acetylatiott takcs place, to a slightly lcss dcgree than in normalseconclary acetatc. The fibrc is washed in water, lubricant isacldecl, arrcl it is dried in warm air. The crintp of the l ibre isretained throughout the process.

Acety lat ion by th is technique does not cause degradat ion ofthe cellulose to the extent that normal acetylation in solution<locs. ' f l te accty latcd v iscosc f ibrc is s t rongcr t l tan norrnalsccondary acctate, dry or wet , wi th lower c longat ion.

90


PROCESSING

Scouring

cel lu lose acetate is sensi t ivc to caust ic arkal i , whicrr rcncrs tob.ring about hydrolysis of the acetate groups. yarns anct fabricsshould not be scoured undcr a lka l inc iondi t ions. Sorp

-o, ra

sulphated fatty acid at 60.C., ammonia, or tetrasodiu,n pyrfplos-phate and sur face act ive agent are ef fcct ive. DetcrgenG-nr . , ,oruwidely used.

Illeaching

cel lu lose acetate is a whi te f ibre, ancr brcaching is sc lcro ' rnecessary. I f b leachi 'g is requi red, a lkar ine condi ' [ ions shourd

*"1::1,1.3:.t:i9 frltgrtrlorite, or a soctium chlorite or hydrogcrrperox lc te ba t ,h shou ld be used.

Dyclng

cellulose acetate dirlcrs in its che'rical structurc froln thece_llulosic fibres, such as cotton, viscose ancl cupro. All but a fcwof the reactive hydroxyl groups of the ccliulose havc bccnacetylated, and acetate wil l not, as a rule, acccpt thc dycs thatare normally used for ccllulosic fibres.

When acetate fibre came on the nrarket, its succcssful com_mercial development was prejuclicccl by thc fact that availablcdyestuffs were unsarisfactory for the riew fibrc. N.; iy;;;f;-; idycstull wcre discovercd for dycing acctate, notably thc i l ispcrscdyes, and acctate can now be cryed satisfacfori ly rn'a wia" rit irtcof shades. Acetate woven fabr i is are norrnal ly l lg dyeA f r . t * . .n60 and g8oc at pFI 6.0 to 6.5 clepenai,ig oii ' tr, i ;ff i ;;;;;;;;;;;

1I-r.1.n:a,t". dyeing. equipnrent can also be used to dyc *uu.,,acetate tabr ics, but is normal ly used to dye acetatc t r icot .

Boi l ing water tends to delustre acetate f ibre, a 'cr cryeingshoutcrbe carr ied out i f possib le at temperatures rowcr

- thar i g5oc.

I Iowever, acetate of 55 acetyr va lue is rcs is tant to < lcrustr ing a ' t ldoes not requi re dyeing at temperatures lower than g5oC.

. Spttrt-Dyecl Acctate. A wide rangc of spun_clyccl acctatc l ibresis now produced.

9 l

H A N D B O O K O F T E X T I L E F I B R E S

Slripping

Treatment with soap solution wil l bring about partial strippingof dispersed dyes. Addition of activated carbon wil l usually

complete the stripping. A stripping bath containing zinc

sulphoxylate formaldehyde and acetic acid may also be used.

fiinishing

The appearance, handle and draping properties of acetate fabricsare generally excellent, and the dimensional stabil ity of- wet

non-iextured,fabrics is good. Finishing processes designed to brittg

about intprovements in these respects are not often necessarywith all-acetate fabrics.

Filament yarn fabrics made from acetate tend to su{Ier fromyarn slippage, ancl f inishes are used to roughen the surface of thefi laments artd create a rustle or scroop.

Acetatc staplc is a constituent of all manner of blended yarns,

especially with viscose staple. The acetate providcs drape, solt

hanclle, dimensional stabil ity and wrinkle resistance. Blendedyarns ancl fabrics of this type may be subjected to finishingireatments which are intended primarily to affect the viscose

fibre, ancl the acetate must be able to withstand the conditions

usect. It shoulcl be remembered that acetate is sensitive to heat,

water and alkali, and l inishing processes should not be used

which subject the nbre to dilute alkali or to water at temperaturesabove 80"C. Dry temperatures should not exceed 140"C.

The thermopiastic nature of acetate makes possible tlt"

embossing of atetate and acetate blend fabrics. Patterns may be

embossed on the fabric by passing it, for example, through a

heated calender.Acetate fibres have a natural sheen which may be destroyed

by incorporating fincly-tl ispersed titanitrm dioxide in the spinningsolution. Modcrn acctatc fibrcs are commonly produced as dttl lgrades in this way. If nccess.rry, a bright acetate may be delustred

by boi l ing i t in watcr , par t icu lar ly in soapy water to wl t ich a

swell ing agent such as phcnol ltas been added.

STRUCTURE AND PROPERTIES

Fine Structurc and APPearance

The length ancl f ineness of acetate l lbres are controlled by the

manufaclurer. Continuous fi laments can be made to almost any

92

"l l,.l r I r I

93

f *f -L*


length. Staplc fibre is .produccd. by chopping the continuous fila-mcnts into shorr rengrhs, wrrich i." uru'oiri "ii*p.J'"ffii"iiy.

38-75 rrn.( l%-3,rf) staple is cornnronly produced for usc oncotton .r 'achinery. 7 S_l2i .r ' ' r ( :_S-- i" j ' r t rpf . i ; t ; ; ; r ;J ; ; ,rvorsted and wool len

.rnachinery, u, ,A'JlS_f g0 nrrn (5_7 in)staple on spun si lk machinery.Continuous filanrent aceiate .is protlucecl conrnrercially irr arange of f i larrre't coylqr, usually

^l .7_j.e' , l i ;; ' i i ' i : ;r,r 'Ji, iStaple fibre nray be as high as zi rt iei fzO a.n; o, inii..

v'v, '/,

.. Thernicroscopic appearance of an acetate filament dilTcrs frontrhat of the rayons but is very ;i,;i i; i; 'thar of rriacerare. .fhefilament is marked uy tongituai'"i i"riJ ancr ricrges. Trre cross-section outlino is buili up ol.os monv u, iu" or six rouncrcd lobcs.If the acetate firaments have not u.en auri.J

-;.in",iriy"iyaddirion of ritanium dioxide "; ;ih";;igments, they are clearand glossy.'fcnsllc Strcngth

Normal acetate f ibre, fornr i .g- the bulk of t 'c output of t ' ist y p e o f f i b r e , h a s a t e n a c i t y o ? o b o u f g . ) _ r 1 . 5 c N / t c x ( t . l _ 1 . 3g/r len). I t does not rose,,r t t . 'gth- io i i iart<ecty as viscose rroeswlren wet; the tenacity fal ls ro f . i_ i?rVt.*(0.65_0.75elden).t ' 'e te'sire srre.pih, of acetate tr;;; i r)ait:15;0-ft);; i,( I B,000-22,000 lb/in z;.

Elongation

23-30 per cent (Standard); 35_4j per cent (wct).

Elastic Properties

At,4 per cent elongation, acetate has a rccovcry of 4g_65 pcr ccnt.When stretched further, thc .f ibre r' inJ.rgoi, plastic .f,;;;

; ibecomcs permancntlv deformc<I ",Ja"., ". it rcturn to its originallength when relcasei. At 5 pcr ""ni ""i"i.,r ion, acctatc has animmediate recovery of.54 pct cen-t,;-ari;y.a r.i,"""ry'"f '35*r*

cent and a permanent set of I I pcr ."nt. Th" .o*"rpo"Ai"gfigures for l0 per ccnt extension or" i l ,-12' and 4l per ccnt.

Specifc Gravlty.

L30.

T I A N D I } O O K O F T E X T I L E F I B R E S

Eflect of Moisture

Watcr i s hc lc l by o rd in r ry cc l lu lose as a resu l t o f the a t t rac t ion

betwcen ttre woter-tovini hy6roxyl- groups on the cel lulose

rrrolecule. ln accrare, t";;y ; i these hyaroxyl groups h^Y:.it"^1

replaced by acetate g,oupi; the inherent attraction of acetate lor

*it , .ot..ules is therefore less than that of viscose or cupram-

moniunr rayons 'Acetate cloes not absorb as much water as the rayons' The

stanclarcl moisture t.g-uin is about -6-5 per cent' Immersed in

watcr , acctatc * i t f swi i i by about 6-14 per ce ' t . (V iscose, . on the

ot l . rcr hand, srvc l ls by 35166 per ceut , a t tc l cupranrnroniunr by

40-62 Per ccnt.)

' l 'hcrnral ProPcrtics

Cellulose acetate is a thertnoplastic material ' l t becomes sticky

ri iso;C. ancl at zos;c. is sofi enotrgh to deform under pressure'

I t nrc l ts at about 232"C'

E,|ect ol lTigh TentPerature

The fibre wil l rvithstand prolonged

ser ious c leter iorat iou. Af ter a week at

its original tensile strengtlt '

Flannrobil itY

Cellulose acetate is not readily f lammable' Exposed to a naked

f lamc i t wi l l mel t and burn '

high temPeratures without

tiO'C., it retains nruch of

tensile strength over prolonged periods'

renrains good.

acicls do not affect acetate, but the

strong acids in concentrated solut ions '

94

Efiect of Sunlight

beterioration after 0,"',".'l?:fJ-J"""'l:'h';','.X'li:fi 'lii:i-r:"',; iii,\li:l3l,l,' I'i' .::J:'i' .oro,,.a

-p igme' ts' " J' tigt'i-ro't tita ni urn

l,flect of Age

There is a s l ight fa l l in

The colour of the fibre

dioxicle grades.Chcrnical I 'roPcrties

Acids

Di lute solut ions of weak

fibres are dccomPosed bY

A : N A T U R A L P O L Y M E R F I I } I T E S

organic ̂.ac ids, inc lu.d ing -acet ic ancl fornr ic ac ids, wi l l nrakeacetate f ibres swel l . At suf f ic ientry h igh co.centrat io .s . a. rcoussolutions of forrnic and acetic aciis w'i lr ,r irroru. .. i iui;;.-;;;;;.Alkalis

Alkal is have l i t t le ef fect up to pH 9.5, brr t s t rong a lkal is causesaponification; the acetate g.oups arc rcplaccd" ty fryar"_yjgroups and the cellulosc acetate is grirlually Jf,^,i 'e.i-"-i"regcncrated ccllulose.

Cetrcral

Acetate is at tacked by st rong oxicr iz ing agcnts, but is not af lcctcdby normal bleaching soluiions of iyiochiorirc or p";";1.i l(Peroxide degrades acetate on long stancting.). The chemical propertics of an lcetatc l ibre <Jepcnd on thcdegree to which acetate gl9up, have rcplaccd hydroiyl groupr'Jn

the cellulose moleculc.. -Thc

moro tryCroxyt gruup, i ir.,; ' ;;;rcr'aining, thc grcatcr is thc fibrc's 'ccirulosic' "i,tru.Lr. r"ru.r.rncommerc ia l acetate has an acety l va lue of 54_55.

EIIect of Organic SolventsAcetate swells or dissolvcs, in many solvents, including accl.oneand

. other . kctones, .mcthyl _ u".tut., ethyi acctatc," ; i";;;;dichloroethylene, cres.ol, p'enol, cntoroform, methylene "i i;;;;;:ethylene chloride. It ' .q insoruble in petroleum che'ricals such aswhite. spirit or petrol. (gasoline), "thyl .t l .,cr, bcnzene, toluenc,

f :"^|t:I": l l lylene, rrich lorocrhylcne, carbon rcrrachlorictc, cyclo-nexanol , xy lene.

Insects

Moths and other insrc l .s do not nornra l ly at tack acctate; grubswi l l .b i te through the f ibres in an ef for t to gct at ' rore at t ract ivcfood.

Micro-orgauisms

Fungi and bacteria may causo surfacc cranragc ancr triscoloration,but res is tance is gcneral ly h igh.

Elcctrical Propcrlies

Excellent insulator.

l : 95

! i , I t: . l l . t.. i ;. :

T E X T I L E F I B R E S

Other ProPertics

Acetate yarns have a.n attractive natural . lustre and a pleasant

handle. The surface of-tft" f ibr" is har<Jer than that of the rayons'

Acetate is a poor conductor of heat' .Acctate yarns and f"b;i* ;;t non-toxic' and do not irritate the

skin.

ACETATE IN USE

Thc introcluction of acetote into commercial use was an excltlng

event in the texti le *oriJ.-rri" chemical structure of the fibre is

funclanrentally difrererii i iom that of any natural f ibre or of any

of the regcncrated ""iruior" rayons. The propertics of acctatc

were, itt consequence;;;tt; diffcrcnt. lrom tltosc of any fibrc in

"."lt i ft. t inro of its introduction' It was' in this respect' a step

iotuota, thc completely synthetic f i.bre'' l ' l te r ta tura l ut t , " i iu#t t i o f ce l lu lose. acetate ' co 'mbined wi th

i t , " r i f " i "p ia" i i . t t p iopt i i i " t ' susta ined a denrat td for acetate

96

I I A N D B O O K O F

cN/ tex

Vo 30 40 .so(% rloNcertot ' t ,

T T r t ' - l r - 1 ' I

A : N A T U R A L P O L Y M E R I : I B R N S

tha t i nc reased con t i nuous l y un t i l l g69 -1910 .In general, modern acetate fabrics can be treated in nruch the

san'ro way as natural f ibres and the rayons. 'fhcy can bc dyccl ancl

finished, washed and dry-cleaned, ancl wil l withstancl all ihe co.-dit ions that are met in ordinary commercial ancl dorncstic use.

It must be remembered, howcver, that acctatc is funclarncntallvdil lcrent in its chemical structure from thc rayons ancl naturalfibres. It therefore dil lers in its behaviour in nrany ways, andthese diflerences must be taken iuto account in thc handling ofacctate materials.

i t must not bctunder prcssure at

about 205"C.This tendency

made use of incmbosscd withnratcr ial .

Acetate is thermoplastic, for example, andsubjected to high temperatures. It wil l deform

for acetate fibres to soften on bcing hcatecl isthe processing of acetatc goods. Fabr ics can bcpal tcrns that arc inrprcsscd on thc warmcd

The rclativcly low moisture absorption of acctatc fibrcs rcndcrsacetatc less l iab lc to damagc by sta in ing wi th mirny substanccs.Fruit juices, ink, food and othcr watcr-iorubre stai.s are clsilvsponged or washed out.

. Acetate fabrics dry rapidly, and are particularly suitable forbath ing sui ts , ra inwear and umbrel las.

Cellulose acetate does not concluct hcat readily; acctategarments are cool in summer and warm in winter.

Acetate has l itt le natural colour; the dyer can procluce acctatcfabrics in a range of shadcs varying from a dJicatc tint to adecp, heavy colour.

The richness and variety of shades, all ied with the softncss anclpliabil i ty of the acetate fibre, have hclpcd to makc acctate into a'bcauty ' f ibre. Acetate garments c l rapc wel l ancl havc an at t ract ivchandlc; thcy arc sof t , and ncvcr harsh. They rc ta in thc i r shapc i fhandled wi th reasonable care and <lo not easi ly wr ink lc .

Acetate fabrics have an unusuaily attractivc crrapc. Acctatcsatins wil l fall naturally in grace[ul folcls; tafrctas retain thcircrispness under sevcre conditions of wear.

lYashing

Thc re lat ive ly low moisturc absorpt ion oI acctntc f ibres con_tr ibutes to the good d imensional s tabi l i ty oI acctate fabr ics whcnwet con)parecl to v iscose fabr ics.


Acetate fabrics clo not shrink or lose their shape appreciably

rvhen rvashecl. They ;r;- ;;t affecte<l significantly by boiling

;;;;, ;;t;";" delustring mav occur' Lustre is generallv restored

;;;;;"j;;. A;;t" ruutiJt wili withstancl orclinarv soap.solutions'

iit.tg""t. and bleaJet, t'ut alkaline conditions should be

avoided.Washing of acetate garments plgs:^njs. no difficulties' either by

f,^nJoi ,iuchine. War"m (40"C', 104"F') water and neutral soap

;;";.;;t;;;i inouto L" ut'a' Agitation. should be sentle and

;;;;;it";ust not u" *tung o9l ot. twisted when wet or thev

ii^v i.i"i" creascs. 'tiey shJulcl be kept flat as far as possible'

NoteMany fabrics for evening wcar' such as. poults' satins' brocades

;;;i;fi;t^t, ar" macle fro-n, acetate' Evening dresses and elaborate

;i;1.;'t-h;;14 be dry clcaned because the construction and decora-

tion of thc fabric nluk. tl 'ttn't unsuitablc for washing at home'

Drying

Acetate garments dry reaclily' They shoulcl be given a cold rinse

;;j;;;;:;i;;l;s, ioiro*'J bv a short.spin (15 seconds)'-Tumbler

Ityi"g-it t"tisfictory prouiO"a that. the drier is run cold before

tf,ippi"ttg. Drying temftratures should not exceed 105'C'

Ironing

Acetate fabrics should be ironecl with a warm iron (HI-CC

s"rii"g zi. i i it pr"r.inule to use a damp pressure cloth' and^ to

;;;^;"" iii"l.u.rr, ,i;;. ii t"rnp.ratur"s. trieir.t than about 120"C.

are used, tne cettuiJse-""ti"it may beg-in to soften and the

ilt;;-y be Oeformed by the pressure. of tho iron' The surface

;i';; -i;;;;

raurtc. w't b""o*l glazed as the plastic lilaments

are flattened.ln commercial laundering, covered presses at 4.5 kg/cnrz

(65 lb) steanl pressure are sat isfactory'

Dry Cleaning

Acetate fibre is sensitive to many types of solvent (see Structure

unJ lrop.rti.s), "ni great care -n'tuit

u" taken in bringing any

"rst"f. ';l".ni

into contact with acetate fabrics' Perchloro-

"irivi.i i., lri.hloroctliylenc or carbon tctrachloride ancl petroleurn'

iypi,-r"f"""ts (".g. Sioctctarcl solvent) may be used in dry cleaning'

98

A : N T U R A L P O L Y M E R F I B R E S

END USES

Acetate l i lament varns,are used in ntany types of rvomcn,s drcss-rvrar, from rinirigs, ri'gerie and gow'i t" rritiiiiu'l;it;';i.,',iblouscs' Staple fibre is usecr in fuller i-,ot"riolr; blendcd with otrrerfibres,acetat.e.staple provides u *iA" vuri"ty of drcss fabrics. Itprovides resilience and resistance to shrin[age in such brcncrs.r. .men's wear, acetate filarnent provicres"r'ai.ii.r, ioi' i i i if,rg,nq

,]::, socks. and pyjamas.. Srallc fibre gocs inro rnany blcnjstlrat are spun into suitings, shirt fabrics aid matcriail i;. ;;;;t;wear.Ma'y f ine householcl ancr furnisrr i .g text i les, a.cr nrater ials nrcnrade fronr acctate, ancl_ thc goocl elccirical insulatio" ;r;;;;;i i;;of rhe fibre rrave carried in irito th" ;i;;i;i"or inoustiy.'i i"i i ,r.ias the insulatcd covering for electric ;il;.

-

CELLULOSE, TRIACETA]-E FTBRES (TRTACETATE)

INTI{ODUCTION'l'hc

early attempts to creverop textilc fibres fronr ccturosc acctatcwcrc concerned very largely with the material obtainccl bt .;;rr:plcte acetylatio' of ceiluiose. Trris is cerruiose triacctatc, iir'*li i"i,thc three available hycl.roxyl groups of cacir glucose unit of thccel lulosc rnolccule arc 'ai l icetyi ; i ; j . " ' -"-"

9 9 .

I T A N D D O O K O F T E X T I L E F I B R E S

Cellulose triacetate is not soluble in acetone, which dissolvescellulose acetate, and few solvents were known for it during theearly years oI the present century. At that time, when attemptsrverc being made to produce acetate fibres by dry spinningsolutions of cellulose acetate, the most satisfactory solvent avail-able for the triacetate was chloroform. And lilament yarns wereproduced experimentally by dry spinning solutions of cellulosetr iacetate in chlorof orm.

This experimental work continued up to the outbreak of Worl<lWar I . In 1914, the I ustron Company, in the U.S.A., began toproduce triacetate yarns in quantities of up to 300 lb. per dayby dry spinning chloroform solutions. This production continuetlon a very modest basis until 1927, when it was discontinued.Trvo factors contr ibuted to fai lure of this early tr iacetate f ibreproject, (l) the use of chloroform as solvent was expensive anddangerous, and (2) the tr iacetate l i laments could not be dyedsat isfactor i ly rvi th thc dycstuf ls thcn avai lablc.

Despite this setback, interest in cellulose triacetate was keptalive by the succcss of the closely related secondary celluloseacctate process. 'I'he development of special dyestuffs forsecondary acetate fibres went a long way towards solving thatdifliculty for triacetate, and eventually methylene chloride wasfound to be a satisfactory solvent for triacetate. This solvent wasmore suitablc than chloroform as the basis for a commercialdry sp.inning process.

With this success against the two biggest barriers to triacetateIibre production, it became apparent that the libre might havevery significant practical advantages over secondary acetate.Cellulose tr.iacetate fibres were found to have a relatively lowwatcr inrbibi t ion and moisture rcgain, plus a high degree ofchernical inertness. They had a high mclt ing point, below whichheating produced irreversible physical changes which improvedthe chemical and physical stabilty of the fibre. These changesenablcd tr iacetatc f ibres to be heat set.

Alter scveral years' rescarch work, Courtaulds Ltd., U.K.,began the commercial development of cel lulose tr iacctate f ibrcsin 1950. fhe rcsultant fibre, first referred to as 'JPS', wasannounced undcr the trade mark 'Courplcta' in 1954. In thatycar, Br i t ish Celancse Ltd. announccd that they werc to intro-ducc ''friccl' triacetatc fibre. Later, Courtaulds and BritishCelancsc linkcd their research eflort and production experience

100

_ I : I - I r l

A : N A 1 . U R A L I ' O L Y M I l l l . I r t B l t E s

arrd norv produce a singlc tr iacetatc f ibre, the traclc nrark ,- I ' r iccl ,bcing retained, with British Celanesc as thc produccr.

-ln 1954, Cel,anese Corporation o[ Americi began productionof a triacetate fibre under the Lrade narnc .Arncl', -ancl

productionof triacetate fibres is now proceeclirrg in sevcraf countrics.

NOMENCLATURE

Sce page 83.

Notc'fhe

infornration in the section which followsto the British fibre 'Tricel,, which rnay becxamplc of a modern triacetatc fibre.

PI{ODUCl-ION

rclatcs pa rt icu lar lytaken as a typical

Experience gained in the rnarrufactule oI scconcl l rry ccl luloscacctate was put to good.use in t l rc cotnrncLcial dcvcioplrrcnt o[ccl lulose tr iacetate. Thc product ion of t r iacetate is, i r i cf lect, astage in the product ion of the scconclary acctate.

llarv Mnterials

Cel lulose in the fornr oI pur i f ied cotton l intcrs or wood pulp.

Prclrcalmcnt

The cel lulose is pretreated in acet ic acicl /water vapout.

Acclylalion

This may be carr icd out in such a way that thc cel lulosc tr jacctntcci ther goes into solut ion as i t is formcd, or rc(ains thc structurcof thc or iginal cel lulosc.

(a) Solution Proccss

Prctreated ccl lulose is acctylatcd by trcatnrcrrt rv i th acct icanhydride and sulphuric acid in thc prc..n." of acet ic i rc i t l . Ast lc acctylat ion procceds, ccl lulose tr iacctatc js fornrccl , an<.1 i tdissolvcs. Thc solut iorr is r ipcncd, nragnesiunr acctatc and wi l tcr

l 0 l

I F F F F f f i FI I A N D I } O O K O F T E X - I - I L E F I I ] R E S

being addcd to replace any sulphate groups on the cel lulosemolecule by acetate groups, and the cel lulose tr iacetate is pre-c ip i ta ted by d i l u t i ng the so lu t i on rv i th r va te r . The ce l l u losetr iacetate is washed unt i l f ree of acid, and dr ied. The tr iacetateproduced in this way has an acetyl value of 61.5 per cent.

A modif icat ion of this solut ion process makeb use of methylenechlor ide as solvent instead of acct ic acid. Smaller amounts ofsulphuric acid catalyst arc necded, and a mi ld hydrolysis pro-duces a tr iacetate of 62 per cent acetyl content and higher, upto the maximum.

(b) N o n-solutiort Proccss

Pretreated cel lulose is steeped in benzene or other l iquidcapable of swel l ing cel lulose tr iacetate without dissolving i t , andis then treated with acet ic anhydride and perchlor ic acid (orothcr acid) catalyst. Acetylat ion procceds, but the ccl lulosctr iacetate docs nol. dissolve as i t is fornrcd. l t rctains thc shapeof the or ' ig inal cel lulose.

The tr iacetate is washed unt i l acid-free and t l ien dr icd. Highrnolecular weight tr iacetate nray be obtained more easi ly by thisrncthod.

Dry Spinning

Ccl lulose tr iacetate from many batches is blended and dissolvcdin methylene chlor ide containing a l i t t le alcohol, to form a 20per cent solut ion. ' lhe solLrt ion is thcn f i l tered and deacrated, andpunrped to the spin neret.

- fhe jets of solut ion emerge from the spinneret into a vert icalspinning tube whcre they meet a streanr of hot air . The methylenechlor idc evaDoratcs. leavins sol id f i larnents o[ cel lulose tr iacetate.

I 'he f i larnents are lecl over an oi ler rvhich appl ies ant istat iclubr icant, anr l are col lected iu the sanre rvay as seconi lary aoettLef i l l rnc n ts.

I f cont inuous f i lanrent yarn is rcquircd, t l re f i lanrcnts from thesp innere t a re co l l cc tcd on to bobb ins by a cap o r r i ng sp inn ingrnechanism, rvhich appl ies a twist .

I f staplc is bcing produced, the f i laments fronr a nunrber o[mult i -holed spinnerets are brought together into a tow. This isc r in rpcd r r cchan ica l l y and thcn cu t i n to s tap ic o f the rcqu i rcdlc r rc th .

102 r03

A : N A T U I T A L P O L Y M E R F I B R E SlYct Spinning

As in the case of secondarytr iacetate may be spun intowater or other liquids whichl l laments.

cel lulose acetate, solut ions of thccoagulat ing baths which containbring about precipi tat ion of the

l\lelt Spinning

Cel lulose tr iacetate is a thermoplast ictr iacetate may be spun into nta-ents Uy

PITOCESSING

I::,".;::" jt:.19: .^._loitt wirh orher fibres, ancl rhe techuiquesl:'.9,._T' i::11t. ar.,. in g.n".al, suitable i;; i;;;",*"i;;:fl:u'j:r^,.^::l loin g, spinn inf r,,,1,l;bi' i;;- co,"i r,. ' rrri.o uu t., ' l ::,.: i l : ' :1r:u arag of triacetate rnakes il , i l" irotl. ro re(luccl.lltl."''r

to a nriniriru'r i. wi' Ci'g .o,, ir,,,iL,ir' nri;;;, i;,,1fi ;;;

nrater ial , and moltenmclt spinning processcs.

yaf l ]s .

Tr iacetate yarns are a l i t t ler r r.rLcL.rLii yarns are a lltt.le more diflicult to size , owing tothc lower moisture take-up as comparcd wi th acel r in Siznc h, ,c^,1parcd with acet i l tc. Sizes biscr lort polyvinyl alcohol, acrylates, ana, ' ' . ,e i l iacryiaicl-are e*cettc, ' , tro r co l t ru tuous t l l an ren t vanr , and n rod i f i ed s ta rch anc l po lyv iny lalcohol, are sat isfacrory with cotton-.p;; ; ; ; r . - ' - '

A relat ively high humidity faci l i tates t t rc piocessing oI t r iacc-t i \ te yarns, for exarnple in kni t t ing o. w.uving. ---"" '

Dcsizing

Watcr-soluble sizes are gcneral ly used,ounng scouring. Enzynre treatrnent wi l l

Scouring

Fabrjcs. neecl a thorough scouringacquircd during proccssirrg. Su rfacc-pnosplratc, with or without soap, ntay(160 'F . ) .

Il lca ching

fr iacctate wil l withstand normal bleaching concli t ions, an<j i tmay bc blcachcd efiecrivcly with hypoclrior: i . Gi: i"o. alkatirrc),sodiurn chloritc, hycJrogcn pcroxicle o. p.rn".t i" '- i cid. Sodiurn

and these are rcnr o vcr lremove s ta rch.

to rentove dir t which isac t i vc agc r r t u r r t l t r i sod i r r r r ibe uscd c {Tcc t i vc l y a t 70"C.


chlor i te is reconrmendcd. When tr iacetate is blcnded with otherf ibres, fabr ics rnay be scourcd and blcachcd, as a rule, by usingtechniques suitable for the other components of the blend.

Triacetate f ibrc withstands alkal ine condit ions much betterthan acetate.

Dycing

Tr.iacetate fabrics can be dyed with most disperse dyestufls. Ingcnera l , I r i gher dye ing ten rpera tu res a re usec l , 90 -9BoC o r eve r tup to I l 0 -120"C. Care fu l se lec t ion o f dyes tu f f s i s essen t ia l wher thigh tenrperature techniques are usecl.

' lhe use of swel l ing agcnts or pressure-dyeing techniques with

Sanderson-type machines yield excel leut results.Tr iacetate f ibre does not stain easi ly, and vat or sulphur dye-

stuf ls may be used with blends to dye the cel lulose component.Whcre these dyes are used, howevcr, dyeing is donc by the two-bath nrcthod; thc tr incctatc is dycd by dispcrsc clycs in thc sccondbath. Dircct cotton dycs can be uscd on thc cotton or viscosccomponent, cross-dyeing blended or melange fabrics in a singlebath.

Blcnds of t r iacetate and wool nray be dyed simi lar ly by normalcross-dyeing methods. Linr i tat ions wi l l be inrposed by the factthat wool is very much more sensit ive to condit ions thantr iacetate.

Tr iacetate fabrics can be pr inted in the same general way asacetate. Disperse colours or vat r lyes may be used. ' I 'he resistanccol t r iacetate to staining rneans that there is l i t t le r isk of rnarkingduring rvashing-off .

Finishing

Triacetate is an attract ive f ibre with a good handle and excel lentdraping qual i t ics. I t is scldonr necessary to apply f in ishes to br ingabout inrprovcmcrrts in thcse rcspccts. Softcncrs arc somctirrcsused, and si l icone f inishcs may be appl ied to increase waterrcpcl lcncy.' f r iacetate

f ibres are oftcn used in blcnds with other f ibres, andf inishcs may be uscd to a{Iect the charactcr of other f ibres inthe blend. I l is neccssary, thercfore, that the tr iacetate shouldstand up to condit ions used in thcse f inishing treatments. As rrulc, t l rc tr iacct l tc wi l l causc l i t t lc di l l icul ty in this rcspcct. Tr i tcc-tatc has a rnuch greatcr resistance to thc cl lects o[ hot water ant l

' I ' I ' I ' I

104

' - [ ' l

A : N A T U R A L P O L Y M E R F I I } R E . S

alkal ino solut ions than has.acctatc f ibrc. I t is not dclustrcd byboi l ing soap solut ions. and has goo,f J i in",rr iu, , , , l . tubi l i ty rul , . , ,hcat set (see below).Blends of triacetate with cellulosic librcs arc cornnronly lrcatctlrv i th rcsin f in ishes to re.uce -" i r i r i " ' r ." . i i i " i , v .r r^c ccl lulosicfibrc anct to impart a firrncr L;;.11..-'6;;;l,it conrrot oI thcfinishing is neceslarv in rho",,- ";.;":^;^^"::::::.'

poor pliat ,.t.ntioo'o,il itlfi;Tfii":"o nruclt rcsin cart causc

IIeat SettingIn the product ion of cel lulose. l r iacetatc, thc hydroxyl grotrps ofthe cellulose molecule h.1"" .b;9;;;;il;; ,,i,;;., cnrircry byaccrate groups. These bulky,

. hyclroplrbfr i . grui ,p; havc changcd' lhc character of the matcrral in several wirys. Thc Iong nrolccrr lcsnrc no longer able ro nack togeth^er-as; i i i l , ; i ; as r l rc or iginl lccl lulosc. molecules, anri the po"wcrftil i;;;;;f ';,1

r^"r io' bct wcc'^y<lroxyl groups is no rorrgcr tt,.r. to l,oli i t ir. ' ,,

i i tt,,..r rrorccurcstiglrtly togcthcr. Whcn ccllulosc t,i...t"i. ' lr ' i ,.*i"|, ".p."l.tty i,,the prcsence of steam. the long .;i";;i;;;;"'iii" ro movo ,rorcfrecty retative to eacli othcr; ;lluio;;-i;i^;;;.;;. rhcr'ro'tirsric.Cellutose triacetate nns, howevei,-;-;;;;;;ll;rricaI nrolcculcthan secondary cel lulose acetate. The tr iacciatc rnoleculc hns asrrccession of .large ncctate groups a tto"trcii'lii- r"gu la r intcrvals:-l,o:,-g

th" molecule, whereas secondary ccllulosc acctate hts a

lilLi:[,?:, l"T, T; f,, ii:. #f .,]l #, il :i,'":,t rl; *::* *of rnoleculcs into rcsular order is thr;; ,;;-;".dily aclrievcdwit h. cct lutose triacctale than wi th ;;;;j.;;;;.i, i".Whcn cellulose triacerare i. t,;"i;l;tir;'ilil.:u frcccrorn ofnrovcment of rhe moleculcs enablcs rh;m i" ; l j ; ; ; thcir posir ionswith respect to one anothcr. i"i;;"-;f;ir;:,"I,ii.,;, wcrc crrscdduring spinning are relic-ve<t,. ;il iil il;",.'-r"il"'r.,r* can alignlhcmsclvcs nrorc prcciscly rnto cryslal l inc rcoiorrsrncsc cl)angcs in lhc inlcrnl. l structurc of t i ic hcl lc<l lr incctatcbring about changcs in the charact". -"f-,f ," ' l i i r i . .

, I . lrc t iglrtcrnrolccular struc^turc is lcss rcatl i ly. p.n"t ini. j bi ' ,noi.tr,r., n,,.tr rc a . rou. t o f water t 'a t

. t r r .e - ' r i i l r . ru i i i r to i i i s t r i r r i r r is r rc t r .l \ foisture regairr fal ls lrom.4.5To i" ' irr", i ' i i . i i . 'n, woult l bccxpcctecl, this increasecl reslstance to rvatcr pcnetratio. is accorrr-prrr ica. by rcducctt atrsorption J ; i ; ; ; l , ir i ; ." ' .1;lini.iittyi,';;;;ils,("., *r,i.r, are alreatty i,, rl,. ilbl'J s,.,'t.t

105

- [ ' I r t '-T --t

II

L-F-F. F. F. F. N F T T h F. F F,T'}}}TI I A N D B O O K O F T E X T I L E F I B R E S

This change in the character of t r iacetate f ibre on heat ing to

," ; ; ; ;" i ; ; ; bi io* tn" melt ing point is cal led heat sett ing' I t

has bccome a lnost lnlportant- i raracter ist ic of t r iacetate and

;il"r"-ti;;;tplastic fibies, provicling a rncans of stabilizing

fabrics and garnrents' especial ly of tei tured yarns' against subse'

nr. ' i i 'a. iot i i tut ion r iur ing praci ical use'' , l i ' " - ' i i iu. . t" te fabr ic is 'heated under condit ions which br ing

rb*; r;;,i;;, ihe molecules of cellulose triacetate will assume

tt o." potitio'n. that represent a nrinimum of strain' And they

*iii t"ia to holcl thcse positions when the fabric is cooled again,

""""- l i i f t " fabr ic is su-bjectecl to heat and/or moisture such as

i t " n " o u n t " r r < ! r t r i n g n o r m a l u s e ' T h e r n o l e c u l c s w i l l g i v e u pih" ir set posit ions only i f the f ibre is hcated to temperaturcs

i t io i i " . i t t "" that userl in sett ing' I f this should happen' a further

ad' lustrnent of rnolecular arrangenlcnt nl ight taKe.place'' " i i " ' i i " . . , " ," i^6t i" is heat set whi lst being held { iat , therefore'

l , * l i i . " .qr i r" a bui l r i ' rcsista.ce to wrinkl ing and creasing, i rrrd

iir" "uifitv to hold on to its heat set structure uuder norrnal

"""ai t i . " i of use. I t can be made into garments which have

"ury-.ur" characteristics, and require no- iro.ning.'

i i " , r t s. t t iug may be taken a- stagc further- by distort ing thc

fuUii" -a"iit

"r-utely into a rcquired ihape before .thc sctting is

carr ied out, and then using ihe sett ing- treatment to hold the

;;;;;;p;;;""entlv in its n-ew shape' lf a fabric is folded for^-;rnpfi,.

and then heated to set tlie triacetate' themolecules in

the f ibres wi l t take up new posit ions that.rel ieve the strains set

irv ,n" A-i . ," i i i "n, "uui"a by folding, and wi l l set l le into si tuat ions

l i ,nini*urn strain. These iosi t ions wi l l then be held unless and

u",if-,f* nU.. is heated to a temperature higher than that at

which sett ing took Place.iriit

-t".rtiiique ofhcat sctting is used. to set pleats and creascs

p";;;;;;;ii; in triacetate garrnints, and to set three-dimensional

shapes in brassieres, .orf t"" t i t t i i i te l ike' Once they have been

hea t sc t , t hese ga rn ren t t - " t ^ in the i r new shape dur ing a l l t l t e

.""ai i i " i t "r hei t ancl I ' t lo isturc encourt tcrecl i r r norrnal use' I lcat

set tr iacetate garments - l iave

remarkable cl inrensional stabi l i ty '

The temperature used in heat sett ing is ustal ly some 30 to

+O;C, trigt er than that which might subsequently te encountered'

"" t" fr fv ]" l r"ning. Fabrics r t ' tay b". subjected' {or example' to

i.'"p.i^,r*, or ico-zao"c. foi pcriocls of 20-30 seconds' Thc

r06

A : N A T U R A L P O L Y M E R F T B R E S

presence of moisture during sett ing tends to increase fhc plast ic i tyof the triacetate, and lower temperatures may bc userl, c.g.125-130'C. for several minutcs.

. l leat sett ing is commonly fol lowed by dccat iz ing, or trcarmcntwith steam at atmospheric pressure.

-This rclie-ves processing

strains. jn the fabric, improving crease-rccovcry and faun<tcr in!properties.

Plcating

The condit ions used in heat sett ing permancnt pleats dcpen<lupon the blend and the construct ion of the fabric. ihe fol lowingexamples indicatc the condit ions that may be uscd:1007o . t r i ace ta te :

_ l i gh twe igh t fab r i cs : 0 .? -1 .0 kg /c rn2 (10_15t?t:n.^)^

Lo. l . l : - mm; heavyweight fabr ics 1.0_ 1.4 kg/cnr2( l 5 -20 lb / i n l ) f o r 30 m in ;

677o tr iacetatel33vo cotton: 1.4 kglcm2 (15 lb/ in2) for 25_30nr in :

60% tr iaceta,tc l40l /o wool: 0.? kg/crrr2 (10 lb/ ln2) for 20 rrr ln.

STI{UCTURE AND PROPERTIES

Irine Structurc and AppcaranccTriacetate is of bulbous cross-sect ion. The f ibrcs show longit t rdinalstr iat ions.

Tcnsile Slrcnglh

T e n a c i t y : 1 0 . 6 - 1 2 . 4 c N / t e x ( 1 . 2 - 1 . 4 g / d e n ) , J r y ; 6 . 2 _ 7 . 1

. cN/tex (0.7-0.8 g/cien) wet. Rat io w;t /dt : 70% approx.

Loop tenac i t y , d ry : 8 .8 -9 .7 cN/ tex (1 .0_ l . f i lUen l .Kno t tenac i t y , d ry : 8 .8 *9 .2 cN/ tex (1 .0_ l . l i don i .

[ longat ion

25-30 pcr ccnt dry; 30-40 pcr ccnt wct.

Ini( ial Modulus

388.5 cN/tex (44 glden).

Spccific Grnvi(y

t .32 .

107


Effcct of Moislure

Regain before heat t reatment : 4 .5 per cent ; a f ter heat t reatment :2.5-3.0 per cent.The Iibre retains 70 per cent of its strength when wet.Triacetate is not delustred by boiling water, to which it is highlyrcslstant.

Thcrrual Propertics

Triacetatc is tlrermoplastic. It di{Iers frorrr acctatc in its heatsetting characteristics. Heat treatment of triacetate increases thecrystallinity and molecular orientation of the fibre. The effectis to set the f ibre in a dimensional ly stable state; the softeningpoint of the fibre is raised, and its water imbibition and desreeof swel l ing are lowered.

After heat treatment, triacetats has a softening point of 225. C.,a fabr ic glazing point of 240'C. and a melt ing point of 300.C.Properly set fabrics have a safe ironing temperature of 200.C.

EIJect ol lligh Temperature

After trvo weeks exposure at 130'C., t r iacetate retained 6g percent of i ts strcngth under condit ions in which nylon retained20 per cent and cotton 38 per cent of their tensile strengths.

EfJect of Lolv Tcttrpcrat urcTriacetate yarn retains i ts softness and resi l iency at extremelylow temperatures.

F larn nnbili ty

Triacctatc mclts and shrivels to a nrol ten bead when i t is igni tcd.Fabrics wi l l burn as rcadi ly as acetate i f thcy arc of opcn wcavc.

Dlle ct of Agc

Triacetate is highly resistant to ageing.

Ellcct of Sunlight

Triacctate is highly resistant. On exposure to severe outdoorweathcr ing there is l i t t le loss in strength and no ycl lowing.

t 0 3

t r L , L i - l . - l r - - l r I r l I . T - l

A : N A T U R A L p O L y r v t E R F T o R E SChcmical propertics

Acids

Triacctatc is resistant to di lute acids, but is attackcd by strongacids in high concentrat ion.

Alkalis

I :" . l l l : has an app.reciably grenter resisrancc to saporr i f icnt iontlran acctate. For this rca.son it can,rot bc

-Acir-,sir..t ty soupsotution or phenol. It resis.rs .airui" ̂ rLri* l"iriion, such asare commonly encountered,in.launctering,rA "tfi"r '*., proccss-ing, but is auacked ancl hy<lrolyzeJ uy'f,""ilil"g'"ir,"rir.

Getrcral

Tr iacetate has a.good resistance to thc chcnricnls cncountcrct lll:.n:lnlol

proccssing. nntt rcxritc usc. tr is ,;i';ii;i;; sigrrificnnttylry con)mon bleachinc ngcnts. and conAit ions,- l , rJuding hypo_:l]l::il:r:_.1]t".i

tes, pcracciic acid. rnd hyttrogcn lcroxirJc. Sortiurrrculonte rs recomrncndcd as a blcaching agint. , - ' -"

trllcca of Orgnnic SolycrrlsTriacetate dissolves in methylene chloride, chloroforrn, formicacid, acet. ic acid, dioxan an<l m. ... ,oi.

- i i- ' iu' swcllcd byacetone, ethylene dichloride.anrl t . i"htorociirvi.nc] r_rio..t,rtc is

:^1-lt: :1",1 .bv.methvlared spir i ts, b;";;; ; ;-; ; i , .nc, xyrcnc,carbon tetrachloride. rerchloroeth ylcnc nn,f niosi- iry.frocr rbons.Trichloroethylcne'm'usr nor t " u."J-in' i l ' ; i l ; ; , ,s, wlr ictr ispreferably carriccl out with. pcrchlor""tfrif.,r" "

". pclrolcunlsolvents such as white sprr.rt.

ntsccls

fr iacctate is not attackerl by.moths or nlost tropicat insccts orlarvae which commonly otto"t t .*t i t" n;;;;" """ ' ' '

lllicro-organisnrs

Triacelate is.highly rcsistant to attack by rn icro.orga n isnrs. pro-Ionged bur ia l i n so i l causcs no to * . o f - i r r " ; l ; i ; , , ; ; . , no r l r i c ro_biological at{ack can bc clctcctecl. oo.. ""t- ffi.ilr"."

109


Ilcctrical Propcrties

fhe electrical resistance of triacetate yarn is very high, and inits unlubricated fornr it is superior to most textile fibres otherthan glass, polyesters, polyolefins and lluorocarbons. The anti-static finish which is given to the fibre before processing helps toreduce the ellects of static to a minimum iri garments and fabrics.Triacetate is very receptive to such finishes.

Handle

Triacetate which has been heat set has a crisp, firm handle whichis particularly suitable for certain types of fabric including su.it-ings and ta{Ietas. The handle does not match that of acetatefibre for garments to be worn next to the skin, such as lingerieand underwear.

' A rnel' 7'riacetate Fibre.

l t 0

1 . 4

t , 2

l . o

&g o '8

r,i 0.6

o . 4

srRArN (% ELoNGATtoN)

A : N A T U R A L P O L Y M E R F I B R E S.I'RIACETATE

IN USE

The chemical relationship between triacetatc and acetatc is aclose one. Yet i t is only in their tensi le propcrt ies that thc twofibres bear any real resemblance to each otircr.- _ In many respects, triacetate behaves more like a synthcticfibre than a semi-synthetic fibre. It posscsscs the thcrnroplasticproperties and the low moisture absorption that wc nssociatc rvithsynthetic fibres.

The low moisture absorption of triacetate is rellcctecl in thefact that the fibre retains some 70 per ccnt of its strcngth whcnwet. Fabrics made from triacctate are casily washecl and wiil dryquickly.

The heat setting characteristics of triacctatc are of grcatpractical value. When fabrics are heat set they arc rendcred frcefrom shrinkage, and acquire excel lent dinrensional stabi l i tv.Thcy arc sct pcrnrancnt ly in the dcsircd shapc. Morcovcr, l rcntIrcatntcnt incrcascs thc fastness of thc dycstul ts to washing nndlight if they have been applied prior to Leat treatmenr.

Heat treatment is used to pro<tuce permancnt efTccts in fabricsmade from triacetate. tPermanent pleats are put into wovcnfabrics of all types, and permanent embossccl cfiects into knittcdand woven mater ials. The permanency of pleats in blcndcdfabrics depends upon the amount of t r iacetat i in the blcnd. lntwo-component blends with cellulosic fibrcs, for exarnplc, nminimum of 67 per cent of t r iacetate is reouired.

-The high melt ing point of t r iacetatc prouid", a widc marginof safety in high ternperature trcatment usccl in clothing nraiu-facture and laundering.

Triacetate fabrics have little tendency to shrink even bcforeheat treatment. As a result , t ighter construct ions arc rcquircd intriacetate and triacetate blended fabrics than in equivalcnl fabricsof acctate.

Tr iacetate docs not shr ink and t ightcn up thc fabric duringsubsequent dycing and f inishing.

\Yasbing

Triacetate is not affected by hot water, soap solutions or rnilclalkal is such as are used in laundering. Gainrents which hnvebeen heat set are dimensional ly stable and do not shr ink.Laundering of t r iacetate presents no problcms.

l l t

I { A N D t r O O K O F T E X T I L E F I B R E S

Clothes ntade with triacetate resist soiling and are generallycomplctely washablc, quick drying and easy to i ron. Fabricsmade fronr triacetate should bc rvashed in warm (40'C., 104'F.)water using detcrgent or soap flakes. Garmcnts with complicatedpleats should preferably be washed by hand, but many garmentswith sinrple plcats and most non-pleated garments may be givena nr inimunr machinc wash.'I'riacetate

should never be bleached. Squeezing or wringingshould be avoided.

Drying

Triacetate dries quickly and easily, rcsenrbl.ing fulty syntheticfibres in this respect. After washing, pleated garments should begiven a hand-hot (48'C., 118"F.) r inse and dr ip dr. iecl in theirproper shape. Other garments may be drip dried or given acold rinse and a short spin (15 scconds) followed by line drying.Tumblcr drying is rcconrnrcndcd for tr iacctate but i t is csscnt ialto run the drier cold before switching ol[.

Ironing

Triacctatc garnlcnts should be ironed damp on the reverse siclcwith a warm iron (FILCC Setting 2) or a steam iron.

Dry Cleaning

Trichloroethylenc must not be uscd. Perchloroethylene or pctro-lcum solvents (e.g. Stoddard solvent) are recommended.

END USES

'l'riacetatc is established in warpknit garments in underwear anct

lingerie rvhich retains its shape, and in woven and knitted fabricswhich do not shr ink or cockle. Tr iacetate is being used with woolto confer i ts non-shrink charactcr ist ics on the blend, ancl isblendcd with cotton and viscose to produce cloths which arcconrplctely stable and fornr pcrmanent plcats.

Triacetate's drip-dry properties, and the fact that many triace-tatc fabr ics nccd no ironing, have establ ished i t as a l ibre foruse in ease-of-care skirts and dresses. On the other hand, its highnreltirrg point pcrmits it to be used in blcnds or applications wheiehigh ironiug temperatures are l ikely to be usccl, such as mixturesrvi th l inen, or in industr ial appl icat ions.

I t L

n ',fi ._l .*l --r ! I -t ' I r

l r 3

.T

A : N A T U R A L P O L Y M E N F I D R E S

- Tr iacetate's non_staininrr", r"ur.Joir,';ff ffi i:i,[:?;;';,:.'"0' it parricurarrv uscf ur

u#",.1'""Jf;,:"?l"of?,Jlg., :rlects. obraina blc in ra brics rrr acte.,,, r i, t. -u n a ir ":1" ;l J;'i'r""",;:o r ii T' i Jn J Hfi ?,., :,,I.":,liwrtn corron. Blendetl *,, ,1,ygo,, tr i"""t" i"-!r." iJcs fabrics inwhlch the warmth of woa'd drip dry propcrries "ii.t:.;,"#:t"ed

with thc hcat sctiiril


t 4

A : N T U R A L P O L Y M E R F I B I T D S

3. PROTEIN FIUTES

Inlroduction

In producing wool, s i lk ancr other aninral f ibres, Naturc nr irkcsuse of the long-chain moleculcs of proteins. 'Tl icse

arc thcll!"f::'-:o","ining organic substanccs ih;i ;i;y a"vitat rolc inthe-structure and processcs of l iving matter.

Only. a minor proportion of the'availabie protein is uscd forproducing natural libres in this way, ancl it has lonf bccn rcalizcdthat suitable non-librous proteins "outa p"rtrops t'e -manipulated

to bring them into libroui form. p.","ii. -fr"i"

t-rrg motcculcs,the. primary requirement of a fibre-fornri"g r"rr.i^ii.". But thcmolecules must be brought into some ."r i . i- . ' f ie""lcnt withcach other i f they are to frovidc o nUr"-. --^'

r n m!rny protcins, {he Iong molccules arc coilcd into a cor'pirctball , with coils- bciug rinkcrr togcthcr in prn."s rrv . i icri icnl borrds.If the molecules of these so-inlted st;i,,i;;;r;;i,;,, arc ro bc

AUtlto-ActD

GLYCINE

CHEM|CAL STRUCTURE

NH2 Ct12 cooll

S YMEOL

o

CYSTINE HoOC. CH NHa . Ct-tes. S. ClJa Ct.l NH2. COOHT H R E O N I N E cH! cHoH. CHNH?.COOH

- - - o

- - - i:-f r-r r----_---'i t-|.\

Pro le in. molecules are fornrcd by l ink ing togcther snra l l ar r r i r ro ac i r lmoleculcs in diflcrcnt proporriorrf and i,' ' i ifr;i;i i ';;q;.ii... rt," ",uiuuacids sholn above, for ciarnplc, couki U" ri^-t".i' iiil,i,ii,i,i"r^trt" *"yr,two examplcs being given.

l ' I 1 5

I I A N D I } O O K O F T E X T I L E F I B R E S

brought into al ignment in such a way as to form a f ibre, they

must l i rst be subjected to some treatment that destroys the cross-

l inks and permits the molccules to be uncoi led. This process is

called dcnaturirtg.When a globular protein has been denatured successful ly, i t

may then be possible to dissolve the protein and extrude the

solut ion through the f ine holes of a spinneret. As the jets of

solut ion emergc, the protcin is coagulated to form sol id f i lanrcnts.

In this way, i t is possible to make useful f ibres from certain types

of protcin.I i a protein is to be of value as a raw mater ial for nraking

textile fibrcs, it must be availablc in adcquate quautity, and it

nrust be cheap. A uumber of proteins sat isfy these basic require-nrents; thcy are conrmonly by-products fronr some industr ialproccss. Anrong them nrc casein, zein, arachin and soyabeanDrotcin.

Cascin is avai lablc in thc skimrncd nr i lk which rctnl ins I f tcr

butterfat has been retnoved; zein is obtained from nraizc, and is a

by-procluct in starch manufacture; arachin (groundnut protcin)

and soyabean protein are lef t behind after the extract ion of oi lfor margirr ine and cooking fats.

'I'hcse proteins have all bectr ttsed with varying degrees oI

success for producing protein fibres, brrt only casein libres havcsurvivecl to beconte a commercial ly important product.

In gencral , rcgeucrated protein f ibrcs tend to be weak' The

rnolecules do not al ign thenrselvcs with prccision and regular i ty

to form crystal l ine regions . in the l ibre, and they cannot hold

t ight ly together to provide the tensi le strength that is character ist icof f ibres with crystal l ine structure.

Like wool, regencrated protcin f ibrcs wi l l stretch easi ly; but,

unl ike rvool, they do not have t l re elast ic i ty that enables them to

return to their fornrer lengt l-r af ter bcing stretched.

Federal 7'rade Conrtrrission Dclinitiort

The gcncric lerrn azlon was adopted by the U.S. Federal Trade

Commission for fibres of the rcgcnerated protein type, the oflicial

def ini t ion being as lol lows :

Azlon. A I lantt factt t red f ibrc in which thc f ibre-fornl ingsubstancc is conrposcd of any rcgcueratcd natu ral ly-occu rr ingprotcl ns.

l 1 6

FI L{ '_1 '*I --1 -I n I ' I ' I r l ' [

tt7

INTRODUCTION

N A T U R A L P O L Y M E R F I B R ! S

CASEIN FIBRES

As long ago as 1898, solut ions of cascin wcrc being spun cxpcri_nrentally to form fibres. casein solutions wcre forcc-cr tirrougli firrcjcts into hardening baths, forming sol i<l f i lanrcnts in whi ih t t rclong casein moleculcs had been givcn suf l ic icnt or icntat ion tohold toge.ther in typical fibre forrn. These carly cascin librcs wcrccommercially of little value. They wcre briitlc antl hnrcl, arrcllacked the resi l icnce and durabi l i ty ncc<lcd for tcxt i lc usc. . Ihcyswclled to a high degree in watcr and.tcndcd to stick togcthcr.

During the early 1930s an Italian chcnrist, Antonio l:crrctti,experinrented with casein Iibrcs to try ancl ovcrcome thcir <.lrarv-backs. He was successful, making cas"in libres which wcrc plilblcand had many of the propcrt ics associatcd wi lh wool._.. I rcrrct t i sold his patcnts to n largc I tnl ian rnyorr l i r rrr _ Srr inViscosa - who devclopcd thc largc-scale nranufucturc of cascirrf ibrcs under the tradc-name of .Lanitat ' , In I936, thc output of' Lan i ta l ' was abou t 300 ton l r cs , by thc fo l l o rv ing ye : r r ' i t hu t lle^r"]gd 1,200 tonnes, ant l in 1939 t l rc product ior icapacity rvrs10 ,000 tonnes a year .

Casein fibres have since bcen produced un<tcr various nanrcs irra number of countries, e.B. ,Lanital' in Ilclgium antl Francc,'Fibrolane' in lJr i tain, 'Merinova' - an i lut)rovccl forru ol ' t l rc.o r ig ina l ' La r r i t a l ' - i n I t a l y , an t l 'W ipo lan ' i n i , o l i t n t l .

N oteInfornrat ion in the sect ion which fol lows is bascd upon ,Fibrolunc'produced comrnercial ly by Courtaulds Ltcl . in the'UK. Alt l io irglrproduct ion has be-en suspended,.Fibrolane'can bc rcglr t lct l as- ltypical example of a conlnercial protein f ibre.

PRODUCTION

An outl inc of the production proccss is shown on pagc I19.Rarv Material

Cascin is obtained by t lrc acid trcatnrcnt ofcascin coagulates as a curd which is washcd

sk i runrcd nr i lk . T l rca ntl dricd, and thcrr

, - I - [

. F F. F. F T F F. F T T F. F, F.T}}} I A N D B O O K O F T E X T I L E F I B R E S

grou.nd to a f ine powder. 35 l i tres (7.7 gallons) of skinrmed milkproduce about I kg(2 .2 |b) o f case in .

Spinning Solul ion

Casein is blended to minimize the effect of variations in quality,and is tben dissolved in sodium .hydroxide solution (caustic sodaj.The solut ion is al lowed to r ipen unt i l i t reaches a suitableviscosity, and is then filtered ancl deaerated.

Spinning

Thc spinning solut ion is wet spun by cxtrusion through spinneretsinto a coagulating bath containing, for example, sulphuric acid(2^parts), formaldehyde (5 parts), glucose (2d parts)- and water( 100 parts). The jets of solution coagulate into filaments in arnanner sirni lar to. the coagulat ion of v iscose f i laments. They arestretched to some degree during coagulation.

- -

Up to this stage, casein spinning is simplcr than that of v iscoscrayon, as the condit ions are not so cr i t ical . But subsequent pro-cessing may become more jnvolved, as it is necessary to treat thef ibre cbemical ly in order to harden i t .

.The newly-coagulated casein filaments are soft and weak, andrvill .break. easily if handled. The spinning process has aligned thecasein molecules to some extent, but they are not organiled intocrystal structures comparable with those of cellulose. Wut., p"n"-trates readi ly into the case. in f i lamcnt, pushing apart the longcasein molecules and softening and swel l ing.the f i lament.

The ellect of water on untreated casein ii such as to render itof little use as a textile fibre. If casein lilaments are to be ofpractical textile use,. they must be treated in such a way as toenable the long molecules to holcl together in the presence ofwater, retain.ing an adequate degree of strength and dimensionalstabi l i ty.

In .c9mm91 with al l proteins, casein is a highly react ivernatcr ial , and i t is possible to makc use of this act i -vrty to cre. l tccross-links betwecn adjacent cascin moleculcs. Such crosslinkstie the casein molecules together, and prevent thcm being forcedapart by water molecules. Crosslinkecl casein acquires anincreabed resistance to the elTect of water, retaining a higherdegree of tensile strength and resistance to swelling.

Many methods of increasing the water resistince of caseinhave been developed, and several techniques have been used

I l B


a u s t t c S o d aa h d w t t a t

OEAERATION

S P I N N I N Gthc. solut ion is forced through jctr into anacrd coagutat ing bath and drawn of i ovarr o l l e r a 5 c o n t i n u o u s t i b r s

CUTTING INTOSHORT PIECES

BALING

TT!!Tt]Casain Fibre FIow Clnrt

I 1 9

I I A N D D O O K O F T E X T I L E F I B R E , S

successful ly in pract ice' The process is coluntort ly clescr ibed as'harclening' , in that i t minimized the softening el lects of water '

Trcatmcn-[ ivith Iormatclehydc forms thc basis of many hardening

techniqucs.ln a typical casein libre production process' bunches of fila-

nrents are^collected togcther into a tow as they leave the coagula-

t ing bath, and are t l ten stceped in formaldehyde solut ion' The

filn-nrents may be subjected to further strctching at this stage'

After treatment, the tow is washed and dried, crinrped mechani-

cal ly, and then cut into staple. The staple may .be- nrade into tops

for -blending

wit l -r wool, or may be blcnded during the carding

stage.

PROCESSING

S p i n n i n g

Casein f ibre is produced almost cntircly as sti tplc, tow or top' Asmall amount of f ibre is used for 100 per cent casein goods, butmost casein fibre is blended with wool, cotton, rayon, nylon andother synthetic staPle f ibres.

Blenris containing casein may be spun on al l the usual systems'

Cotlon Sy slentFor use on the cotton ancl nrocli l ied cotton systems, casein f ibre

is oroducecl, for exanrple, in 3.9 dtex (3.5 clen),50 rnnt (2 in) or

65',n,u Qi in) staple, ancl 5.0 dtex (4.5 den), 65 nrm (2% itt)

i trpt.- Vir.ote' staple' is comutonly ble.nclecl .with caicin for

sDiirnine on the coitom systern, a typical and highly successfulfr- i . .a f i , t i"g l /3 casein, i dt.* (4.5 ien),.65. ntnt (2tA in) and

2/3 v iscose 's tapte , : . f c l tex (3 den) , 65 mm (2% in) '

lVoollen Systertr

For use on the woollen systetn, casein f ibre is produced, lorexanrple, irr 5.0 dtex (4.5 i len), 50 and -55 ntrn (.2 an<I 2tA in)s tar r lc , ant t l0 d tex (9 dcn) , 65 ar t t l 100 nrnr (2% and 4 in )staple. For carpet blends, ireavier deniers, are produced, e'g'20 'd tex (18 der i ) anc l 33 d tex (30 den) , l l5 nr r t r (4% in)s tap le '

I l lencle<l yarns spun on the woollcn systcm comlnouly corrtainabout { caicin anrl } wool or rayon staple. Highcr proportionsof caseitr - up to l ' - arc uscd in producing blcnded carpet yarnscontaining coarser f i bres.

l ? 0

rU],-J_1_-LJ1' L L L] L I I q L t ' L' L L L L L H

A : N A T U I I A L P O L Y M E R I I I D I I I ] S

lVorstcd SyslentFor use on the worsted system, cascin f ibrc is procluccd in 3.9,5 . .0 ar rd .10 d tcx (3k ,4 t /2 , .9 < len) ,100 ar r t l 150 nr rn (4 and ( r in jstaple. These f ibres are blended with rnerino or f inc cross_bretlrvools, or rayon staple, for the rvorsted industry.

FIax SystenrCtrt tow is conrnronly uscd on this systcm in ort lcr to rcducc ncpfor rnat ion, e .g . 5 .0 and 10.0 d tex (4 .5 and 9 dcn) cut to t50 nrnr(6 in ) s tap le . ' l 'h is nray be b lendec l , fo r cxar r rp le , w i th 5 .0 r l tex(.411 clen) cut viscose tow or bright rayon stapte.antl proocssedin to yarn without cornbing.

Coarse f ib res , e .g .20,33 d tex (18, 30 den) ,200 r r r rn (B in )staple, may be used on the f lax and jute systcnx of proccssirrg ir ithe product ion o f carpct yarns. F ibrcs o f these c l i rucr rs ions arcusua l ly b lended wi th 20 a .n t l 56 d tex ( lB and 50 t le r r ) n l i r t t rayonstap lc o f a s i rn i l t r s tnp lc le r rg t l r , nor rna l s t i rp lc f lb rc l rn r l l ro t c r r ttow be ing-used for b lends o f th is type in i rnour r ts o f 'up to 50per cent o f case in .

Sizing

Warps made of staple f ibre blend yarns containirrg c:rscin nraybo sized sat isfactor i ly f rom back-beams, ci ther by the ,CottonSlasher System' or by the 'Rayon Slasher Systern' . Short warpscarr be prepared by sect ion warping and sizcd bclrns, to bcaiuon a normal mult i -cyl inder rayon sizing machine.

I t is important that the const i tucnts of thc size uscd shoul<lbe readi ly removable, i .e. they shoul<I be complctely rcmovablcfrom the woven fabric by a mi ld scouring trcatrnent which corn-pl ies with the condit ions sugges(cd.

Among the morc common readi ly rcmovablc siz ing ntatcr ialssuitable for use with casein blcnd yarns arc:

l . Tho water-soluble ccl lulosc cthcrs, and2. The water-soluble starchcs ( i .c. rnodif icd starchcs, starclr

cthers and starch cstcrs).

The starch should contairr a lubr icarrt , a rvater-dispcrsible oi l( i .e. one containing a mineral or vcgctablc oi l c l issolved orcl ispcrscd. in a sulphonated oi l ) being the rnost sat isfactory.Such a lubr icant is readi ly compatiblc with tn aqucous solut ion

l2l

TTT F F h F T I T h E E E E E E E E I:H A N D D O O K O F T E , X T I L E F I B R E S

of one of the starch or cellulosc derivatives referred to above,and is, ntoreover, easily removed from the woven fabric.

Using a Rayon Slasher, rayon/casein blends yarns may bedried after siz ing, at a maximum cyl inder temperature of I10.C.Casein blends with acetate or other thermoplastic fibres shouldbe dried at a maximum cylin<Jer surface teritperature of 100.C.

Using a Cotton Slasher, the maximum temperatures shouldbe some 5"C. lower in cach case.

It is preferable to aim at obtaining a stretch during the sizingoperat ion of not more than 3-4 pcr cent. and to have sonre5-7 per ccnt of size on the warp yarns for satisfactory weaving.

IYcaving

There are no special difiiculties in weaving blend yarns, e.g. ofcasein and rayon staple contairr ing up to { of casein, ei ther assingles - sui tably sized, or as unsized folded yarns.

Desizing

Enzyme products may be used, preferabty at pH 4.0 to 6.0. I fwater soluble sizes have been used, desizing is not neccssary.

Scouring

Syntbet ic detergents should be used, preferably under acidcondit ions, e.g. pl l 6.0

Illcaching

In common with all wet processing, bleaching should be carriedout if possible under rvedkly acid conditions, e.g. pH 4.0-6.0, ascasein f ibres retain maximum strength and minimum swel l ingunder these condit ions.

Hypochlor i te bleaches should not be used.Bleaclring may be carried out with two volumes hydrogen

peroxide buffered to pl l 8.0 rvi th I kg/24 l i t res sodiunrpyrophosphate. Alternat ively, an acid stabi l izer nray be used.Bleaching can usually be ellected cold, by steeping overnight.

If alkaline processing is used, it must be followed by carefulwashing and acidi f icat iorr with acet ic acid.

Optical bleaching agents miry be appl ied as for other f ibresand blends.

l)

I

l22 t, { ' t23


Dycilrg

Casein absorbs moisture readi ly and does not havc a highlyorientated structure. Dyes can penetrate into thc fibre witfioritdifiiculty.

In general, casein can bc dyed with dyestu{Is use<l for wool.Acid, basic, direct and disperse dyes are use<l where goodwash. ing-fastness is not a pr inre essent ial . Carbolan and Ncolandyes give superior wash fastness.

It is essential to employ modifie<l techniqucs in the tlycingprocesses if the desirable propertics of cascin fibre are to bcpreserved. In part icular, i t is neccssary to establ ish carcful controlover pH and temperature. Bullerecl systems should bc use<j tokeep the pH of the dye liquor between pFI 4 and 6.

Casein Staple Fibre ond Continuous TowCasein staple is commonly dycd for cvcntuir l usc ns prcsscd fcl ts,needleloom carpets, or in woollen blends to bc usc<|, ior exnn.,pl",in coatings. For these purposes aggrcgatecl or nrctallizcd iciridyes. are mainly uscd. Selected chrontc t lycs providc a highstandard of fast ness.

Continuous tow is dyed for var ious purposcs, nncl lcvcl l ing oraggregated dyes will usually provide thc rcquircd fastness. I,Icavicrdeniers require less dye per unit weight titan finer dcnicrs, anclat the same t ime are more readi ly penetrated by <tye l iquois.

Casein taken from thc balc is clean ancl alrnosi ncuiral , ancltvi_fl noJ, as a rule, require scouring or treatment before <lycing.After dyeing, the f ibre should be r inscd and given a soft nnish,fol lowed by the appl icat ion of ant istat ic agent. Cont inuous towis usual ly given the soft f in ish, but ant is iat ic agent is seldomappl ied.

Caseinllltool Blends, Staplc Fibre or TopsBlends of wool and cascin arc sometinrcs t lyccl in thc forrn ofstaple fibre in the woollen trade, or as tops for thc worstcd tradc.The procedure is simi lar to that usccl with cnscin alonc, butgreater care is needed in dye select ion to producc a sat isfactorysol id shade on both f ibres in the blcnct.

I t is preferable to convert tops to hankcd sl iver ancl dyc innrachines of the Obermaier type.


ln dyeing these blends, i t may be neccssary to raise the tem-perature sufliciently to ensure adequate dye fastness on the woolconlponent.

Casein/wool blends are also dyed as yarn or fabr ic, and asvarious forms of felt. Dyes cornmonly used include levelling,aggregated, metallized acid or chrone dyes, and dyeing of yarnsis carried out in the Hussong machine or in package form, andpiece goods in the winch.

Levelling acid dyes for carpet yarns, certain woollen-typecloths and felts, are selected from those of this class with neutraldyeing properties. Dyeing is carried out at pH 4, f.or f hour atthc boi l , and thereafter sl ig lr t ly bclow the boi l .

Aggregated or metallized acid dyes, or chrome dyes, providea higher standard of wet fastness for hosiery yarns, part icular lyin darker shades, and for some worstcd-type cloths. Most of thcaggregated or metal l ized acid dyes are appl icable at pH 6, anddycing is usual ly carr ied out at 90-95'C.

Selected chrorne dyes are suitable for dark shades of highwet fastness, using ei ther the chromate or the after chromemethods of dyeing.

Cascin lCellulosic Fibrc Il le nds

Blends of casein rvi th cel lulosic l ibre may be dyed in the yarnform for thc hosiery and carpet trades, but thcy are more cont-monly dycd as [a b r ics.

Yarns are dyed on the Hussong nrachine, or may be packagedyed on cone or chcese; fabr ics are usual ly dycd on a winch.

For nrost general purposes, these blends are dyed to sol idshades with direct dyes and the addit ion, i f necessary, of aggre-gated acid dyes. As a rule, Class B direct dyes are of greatestinterest; they have the least af l in i ty for casein and permit theuse of acid dyes on the lat ter.

Suitablc acid dyes are drawn fronr the aggregated or metal l izedclasses of dye. In general, dyeing at high tcntperatures wi l lfavour thc absorpt ion of dircct dye by the casein, but thcrelat ive rate of dyeing on a ccl lulosic f ibre and casein can bccontrol lcd by carelul addit ion of sal t and Calsolene Oi l HS. I tis also possiblc to produce other attract ive clTects by dyeing thccasc, in only with aggregated and metal l ized acid dyes.

Cel lulosic blends, being dyed with direct dyes, do not usual lyrcquire bul lercd systenrs, as they have alrcady been proccssed

- t t . , l r I r I

t24

[ ' l r - t

A : N A T U R A L P O L Y M E R F t D N E Sunder sl ight ly acid condit ions d ur ing. _ scouring. fhc clyc l iquoris therefore adjusted to pH 6 Utf, uiitti"l.iu:" i.i.l, the goodsreceiving a final treatrnent ut pl-I q aftcr JV.i,ig.-

--'

Drying

After dyeing, loose stock ,and. yarns may be centr i fugal ly hydro-extracted bcfore bcing dr ied in convcnt ional ni i in i . -lo.vcn labr ics may bc hydro-cxtractcd by opcn wit l th suct ionnrachine, or.by centrifuging^in open width. if basket typc extnrc-lors are used, excessive running timc shoulcl U. ouoia.a to prcvcntdevelopment of creases and- crack rnn.Lr.

-f-iigfi- rpec<I watcrmangles are not reconrmended.

A recontmended drvins proce<lure is cither to tlry on a slackdrier, followecl by stenteiing, or to <!ry and finish on an ovcr-fced stenrer. Ir is essential to allow "r'o;;qr',;;;;;rinkage fronrgrcy to f in ished dimcnsions.

I'rintirrg

Casein blend fabrics rnayrcsul ts nccessitatc thorougha l tglr t t reatnrcrrt with a lowis essential.

be pr intcd vcry cf l 'cct ivcly. Coo<Ipreparat iorr . I f --s ingcing is rrcccssary,burncr wi l l sul l icc. A thorouglr scori i

Casein fi_b-rc is generally white, and. bleaching is not usuallynecessary. If required. however, a rt�il<.l pcrborite or pcroxidebleach should be used una.. "ont.oii.;-.;;;i;;;;:

**lt-::_f'_"!.'ing, the fabric should b" G;;';;';i'c rins, un<tcrmlnlntum warp tension, followed by white room stcutcring toa stable width. Alternatively, tlie fof.i"rnny-fr" a-ri.d dircct on anenclosed stenter. In all casls, high t".p.iitr."r* oild ou"r_,t.yi,,gshould be avoided. Whire room -brr.hi;;-.1;;;tl

b*"" unn"..r."ry,but if employed, care shoulcl be takcn &;;iJ;.;;rcing a hairysurface.,Fabrics

-containing casein may. be pr intc<l by block, scrccrr,rollcr, surlacc roller, and rno<Jificcl pnp., irilnr# nr"cilrous. ncitt,

B:rt;;.11r..,, chrome, mordant, nroi",'uot'of'p-ig,.r,.n, .ry.. ulny

Acid.or dircct dycs shoul<I bc applied in a sl ightly acid orpotential ly acid paste. In.sonre. .or. i , i t ,nny b""n""".s[ry romodify thc viscosity of tnc pnrrtrng paste in orclcr to obtaindefinit ion similar to that obraincd *ir i i .y"i , , "wolt

o, .ottout25

TErrr t t t t t F.Frr t I t t t t II I A N D B O O K O F T E X T I L E F I B R E S

fabrics. Casein blends wi l l require a less viscous paste, forexample, than 100 per cent rayon fabric, and sl ight ly moreviscous paste than that used with 100 per cent cotton.

The rninimum amount of alkal i should be used on al t pr intmixtures, but vat dyes may be pr. inted by the potassium carbonateformosui method and naphthols may be applied in the usualnlanncr, bullering being advisable. In many cascs, it is preferableto use the Rapidogen form of azoic combinat ion. In general,normal pr int ing procedures nray be fol lowed, but i t may benecessary to modify the printing mixtures slightly in the case ofcertain dyes, knowledge of which can be obtained frorn ordinarvswatch p r in t i ng .

Normal ageing and steaming procedures may be fol lowed,but unnecessary and excessive steaming should be avoided,espccially in the presence of alkali. After ageing or steamingthe fabric should be washed off quickly and not al lowed to standovcrnight. The fabric should not be f inishcd. in an alkal ine statc.

Str ipping

Part ial str ippirrg of blends of casein with wool or rayon staplernay be achieved by working the rnater ial at approximately 80.C.in a clean l iquor containing 5 per cent of Calsolene Oi l HScalculated on the weight of material.

lf more severe stripping is required, this may be carried outin a I iquor containing a neutral solut ion.of sodium hydrosulphiteat approxinratcly 50'C.

Ini t ia l smal l-scale experinrentaI str ippings should always becarr ied out.

I;inishing

Crease-resist l in ishes ntay be appl ied to blends containing caseinf ibre, using telnperatures which are preferably not higher than160"C. (320"F.) for approximately 2f minutes. The polymeriza-t ion may be carr ied out . in a convcnt ional baking charnber, andit should be fol lowed by lhorough rvashing with a neutraldetergent.

The final percentage of added resin, calculated on the bonedry weight of fabr ic, should preferably not exceed 8 per cent.

I{andlc rnay be inrproved by adding proprietary softcningagents to the last wet proccss bcfore drying.

126 127

^ : N A . T U I I A L P O L Y M E I t F I B R E S

-..,1, i !r i" j containing casein f ibre lencl thenrsclvcs rcadily torarsrng. Best results are obtaincd by using ,, 'r l"*.r^," of raising,and dry raising processes are recommcndcd.

Cnrbonizing

Case.in will withstancl the carbonizing treatment when carricd oulwirh the minimum srrengrh. of .ufpir i i " ' "" id ' r ;c;ssary ror thccf lcct ive rernoval of vegctzrble rn"t t"r . af i . r ' " i r . . ,nr"nt, thci]:1il:fl'":"'.

be wellrinse<l "na ",rlu.t".r'i" ou'o wirh sodium

,j:r??l1"g rnay .be ",:..":9 out beforc or afrcr <rycing; ifiiJ.".l3'li'"1#T"':'"i";i:Jif: the generai' t'n'r'n.i or" ir,"

l l i l l ing

Cascin f ibre i tscl f c locs rrot display any nr i l l ing propcr. t ics, nn<Jblcnds of cascin wirh orr,., nii i_,r.it i i l ' ;,;;;r: 'Ji,.r, o. .uyoustaplc or nylon, shoulcl not bc processcd in rrr i l l ing ntacl t i r rcs.

, n ltl'ff " lt -;:'"':l J'fr ,:"""' -i' " v. u"

-''ii r ".1' iu? "" n u, p r", on

thc hcavier type of nn"tl lu-l l3: ' irrg and nri l l i r tg nracli i 'c, or

rniling. The ;1&.";r;"lir"" ;oJ':'..il0'"'"' dcsigncd onlv for

^.ll th,oytg be remenrberecr that brends of casein ancr wool wiilotten shrink more o uicklvi "," i ; J i ; ;;;;;i;; y,,ll i,"[ :: il,,,:ll lH ffi ,,,.:;:"bu;

*l:. A sui(able nri l l ing rncdium is a rni*t, ' ,r"-oi ' i ' i l , o[ soap toI part of synrhetic dercrpent. c..or" n., i i l i , , ! '_'";";: carric<I our: ' ] :1

only. the requirccl imornt of fr"e ai-tai i ' io sanonify rhc

::'$! iT?f d f ti l'Ji "' tr:l' ";, ;i,Y** i*ml'.,l' _.,',,general for most felted structurcs.

,,. 1,-1,]:r."_"gh washing off is essential aftcr scotrring or nrilling,;1, ";:il,,i'#T;ff,;",:o"l::0"',T'j;,lii,Xi

l;j;1at o".. ccnt bascii

:l;::',:"'.li!y*:' jH.?lii'f "',"il'xl'l,:li'';ilff l*i"'i;il''"1^'ifi *'*i,liy*."1:"1;i,11'',;l,t*,,"::fi l*it.t;l jUstrortd procccd u'ri l r 'c pH .-ir..t '""i" i""i,, i l i ir" ' is abourpI{ 4.

T I A N D B O O K O F T D X T I L E F I B R E S

STRUCTURE AND PI{OPEITTIES

li inc Slruclurc and Appcarlncc

The f i lanrcnts arc snrooth-su rfaced, with faint str iat ions. Cross-scction is bean-shapcd to almost round, with a dappled elTcct dueto pitt ing.

Casein can be spun in the form of fine lilaments, with diametcrsof 20-30u..

The natural colour is white.

Tcnsile StrcngthCasein f ib re has a tenac i ty o f 9 .7-8 .0 cN/ tex ( l . l -0 .9 g /den)clry. Wren wet, the f ibres lose much of their strength; tenacityfal ls to 5.3-2.6 cN/tex (0.6-0.3 g/den).

I longa( ion

60-70 per cent, wet or dry.

Spcci l ic Gravi {y

1 .30.

Iiflcct of l\loisturc

Caseirr tends to absorb moisture readi ly, and the f ibres becomesrvollen and soft. They may become plastic and sticky as thetcmperature is raised. Regain under standard condit ions is about14 per cent (cf. wool).

Thcrmal Propcrlics

Casein fibres generally soften on heating, particularly when wet.

E{Ject of I{igh TentperatureThe fibres become brittle and yellow on prolonged heating atover 100"C. Dccomposit ion is appreciable at 150'C.

Flanrttnbility

Casein f ibres burn slowly in air . Flantmabi l i ty is simi lar to wool.

I i l lcc( of Agc

Vcry rcs i s ta n t .

r -- l r l r I r I r l

r28

r I

t29

- I r I r I r l

A : N A T U R A L P O L Y M E R F I B N E S

filTccl of Sunlight

Vcry l i t t le . S imi lar to wool .

Chcntical propcr(ics

Acids

Cascin is stable to acids of modcratc strcngth undcr nornrrlconditions. It can be carbonizcrt with coiJ i "pcr

cent sulphuricacid solut ion.

_.,Casein fibre disintegrates in strong nrineral acids. It rcsistsdilutc mineral acids a-ncl weak. organ-ic o"i.tr, "u.n at elevatccltemperatures; some loss of strength and embrittlcnlenI nlay occurafter boiling for long periocls.

Alkalis

Liko wool, cascin is scnsit ivc to nlknl i . Mi ld nlknl is such nssodium bicarbonate and disoclium hy,lrogcn- piiosptrat" travcl i t t le effect. at low ternperatures. Stron! at izrt is, 'sucn as causl icsoda or soda ash cause severc swelling a-nd will uttimot.ty disintc_grate the fibre.

General

The chemical structure of casein fibre bcars sontc rcscnrblanceto that of wool. Both f ibrcs are proteins, but i l rc-<tetai lc<l con_struction of the protein of casein clillcrs'from ilr"i "t wool. Incasein itself there are no sulphur bridges zuch as thcre are inwool keratin. Bridges of dillerent cheriical typ., ur" built intothe casein during Lreatment with formaldetiyic Ji aluminiumsalts.

Hydrogen peroxide can be safely used as bleach. At hightemperatures it will cause some yellowing.

ElTcct of Organic SolvcnlsDry cleaning solvents do not causc danrage.

Insccts

Casein f ibre is not attacked by.nroth grubs to thc srme degrec f ,swool. Danrage may bc caused, howJvcr, whc' tiic"cas.in fibrcis blended with wool.

T ET, TT} E E-EI T A N D I } O O K O F T E X T I L E F I B R E S

Micro-orgauisms

Casein libres are attackcd by mildews, particularly when moist.

Elcctrical Propertics

Diclectr ic strength of casein f ibrcs is Iow.

Other Propcrt ics

Cascin fibre resembles wool in having a soft warm handle. Thefibres are naturally crimped, and yarns have a characteristicrvarnrth and ful lness of handle.

Casein fibrcs provide good thermal insulation. They areresi l ient, l ike wool.

Case irt ('Merirtova')

t 3 0

A : N A T U I t A L P O L Y M E R I ] T B I T T ] S

CASEIN FII ]RES IN USE'fhe

iow strength of casein f ibre ancl i ts sensit iv i ty to watcr havercstr icted i ts use, but i t has found a number of appl icat ions o[importance in certain textile fields.

. Casein fibres are produced almost entirely as staple, and arcintended pr imari ly as blend f ibres for mixtuie with wool, cotton,rayon,.acetate, nylon and other synthetic staple libres.

In blends with cotton and rayon staple, cascin brings warmth,rcsilie,nce and a full, soft handle. Being of excellent colour,it make.s.possible the production of good whitcs, ancl prolongejwcar trials have shown that the whitencss of fabrics madc fronrthcse ya-rns is preserved throughout the life of the garnrcnt,irrespective of the numbcr of washes it is civcn.

Biends containing one part casein to two prrts rayon staplcor cotton have been found part icuhrly sat is iactory. 1.wi l l arr<lf loat rvcavcs br ing out r .nrxinrurn suppi.nuss in thj f lbr ic, nndlhc crease_ resistance is good. This rnay bc strcngthcncd wherercquired, for example in sui t ings, by appl icrt ion oia crcasc_rcsistfinish. Shrink-resist finishes are aiso- uscd where ncccssary roimprove the shape, stability or resistance to shrinkage on wasliing.

Most of the casein libre producecl today is used in blencls witlrwool. Casein has a soft handle and warmth thl t nrakc i tpart icular ly sui table for this purpose, and i t enablcs the spinnerto produce a yarn of lower cost.

Casein l i laments can be spun to very f ine diamcter, enabl ingthem to blend with thc finest qualitics of wool. Cascin librc oT20p diameter is as fine and soft as the 70s wool used for makingbaby clothes. Casein of 30p diameter is equivalent to 50s wool.

The proportion of case.in used in blends with wool will <tcocn<jupon the ef lect required; one third casein is gencral ly sat isfaciory.

Casein may increase the shrinkage in l in ishing in so*. .on-struct ions, and al lowance should be made for this in the sctt ingof the cloth.

lYashing

Carmcnts containing cascin f ibre should be washcd with carc,and treatcd as gent ly as wool. Flarsh condit ions such as cotton wi l lwi thstand must not be used. High temperatures and strongly aciclor alkal ine condit ions must be avoidLd. Ncutral dcrcrgcnrs arepreferable for washing.

l 3 l

I I A N D B O O K O F ' I ' E X T I L E F I D R E S

Fabrics containing casein blended with wool are obviouslywool- l ike in appcarancc and handlc, and thcy wi l l automat. ical lybe trcatccl and washcd as wool, causing no di f f icul t ics. Blcnds o[cascin rvi th cotton wi l l gcneral ly be wool- l ike in handle, and wi l lbc treated as rvool, but such mater ials should be suitably label ledto avoid any possibi l i ty of harsh treatrnent during washing.

Drying

Garnrents should be dr ied as wool, care being taken to avoidhigh temperaturcs.

Ironing

The ful l , soft handle of garments containing casein wi l l benraintained i f they are only very sl ight ly damp, or almost dry,before being ironed or pressed. Wool sett ings should be used,i .e. warm iron (HLCC Sctt ing 2).

Dry Clcaning

Casein is not af lected by dry cleaning solvents, and garmentscontaining casein nay be dry cleaned as readi ly as wool.

End Uses

Kttittittg Y arns

Cascirr and rvool blends are used for f ingcr ing and nrachiucknit t ing yarns, the whiteness of casein lending i tsel f to the pro-duct ion of pastel shades.

Knitted Fabrics

Worsted spun yarns containing blends of between 30 per centand 50 per cent casein with wool are very suitable for knittedjerscy fabrics rvhere a soft full lrandle is required, together witha widc range of sol id dycd shades, fronr dark colours to pastcls.

Casein/wool blends are used for kni t ted berets, in which adcgrcc of nr i l l ing is required to produce the necessary fel tedst ructure.

For inter lock outerwear, 'T ' shir ts, cardigans, jumpers etc. ,interest ing efTccts ntay bc obtaincd with cotton-spun blcnds of{ cascin, + cotton; } casein,;} rayon staple (spun-dyed), } cotton,

132

A : N A T U R A L P O L Y M E R F I I } R E S

rnd.simi lar ble nds, also . introclucing nylon. Thc conrbinat ionc;rscin and corton for kniucct fabrts i r i "*s� gl" i ' i icxibi l i rygarnrcnt design and knit tcd structurc,

Casein blendcd with wool,. coi lon, rayon staplc, nylotr an<!othcr f ibrcs has many possibir i t ies in inc ncttr oi- ' . ,rcutn,. t uitt . . tpi lc fabrics, Raschcl cloths, coatings, blankct fabrics, ctc.Fclts

Onc of the earl iest uses for casein l. ibrc was in thc mrking offclt for hats. Casein f ibres do not have'a;; iy' ; , , ; i""" l ike woolIibres., but they will soften and. stick togcthlr in *ornl *ot"r,fornring a felted mass. Mixed *itn *ooi, ?or"i,, iil.., wiil rnakethe wool felt more readilv.

Prc.rscd FcltsDlcnds of casein ancl wool arc rnade.into presscd fclts for usc asfloor coverings. The compact fclting ot'tfi"- frf ",rO givcs high,,.:lglL-".19

lr..d-wearing properries i"c"sso.y foi rioo. covcring.-^,r-:-yrt

used lor this purpose increases the rate of milling, a r;lrcouces costs.

C0rpetsBIcnds of rvool and casein are used in corrvcntional and tuftcdcarpcts. The casein contribulcs a high dcgrce of rcsi l iencc, gooJcovering power (low fibre dcnsity), w"rnith, "*""li",rt soil resis-lance due to the smooth cross_seCtion, and rclativcly low pricc.The casein is obtainable for this purposc in purc white naturalcolour, or in a large range of spun-clye<t colouis.

Pile carpets are nrade with 50 per ccnt cascin blcn<lcd withrvool or rayon staple.. Blends of cascin and rayon staple are widcly uscd for necdle-loom carpeting. The casein providcs softncss,6ult anrf warmlh,and 50/50 blcnds of cascin.arr<l rayon staplc "onr1rur" favourablywith an al l-wool carpct in hanile, appcararrci ano wcariugproperties.

Resilient Fillings and padtlings

Cascin f ibre has cxcellcnt insulation propcrt ics, and good corn-prcssibi l i ty and resil icnce. The lattcr propcrt ics dcpcnd to a largc

I J J

o fof

' I ' [ rJ r l .--l

: ' - - - -


extcnt on denier and staple length, and by suitable sclect ionfibre dimensions the characteristics of linished articles mavobtained to sui t requircments.

o fbe

t34


CROUNDNUT PROTEIN FIBRE ('ARDIL)

INTIIODUCTION

The natural protein f ibres, s i lk and wool, possess so many attrac-t ive propert ies that they have always scived as qual i ty hbres inthc tcxt i le trade. But animal_der. ivcd f ibres are, by ihcir verynature, expensive. They are subject to al l the unicrtaint ies,nnerent rn anything of animal or igin. They are expensive, an<lvary great ly in qual i ty. Moreover, in the case of- wool,

' their

product ion occupies land that could be devotcd to growing food.The proteins frorn which these animal Iibres are rirade corne, in

the lirst place, from proteins in .the plants that are eaten byTi.T1lr,o.r

food. These plant proteins difler from animal proteinsln tne detal led structure of thcir molecules. Dut al l prot i ins arcbasically sim.ilar in chenrical design. All protein molcculcs arcin.the.form of long threads of atonrs. plant prot" inr, as wcl l asanimal protcins, are therelore able to sat isfy thc nrst rcquircr l rcntof a fibre-forming material.

The successful production of-.Lanital', ,Fibrolane,, ancl othercase. in f ibres showed that non-f ibrous ar i inraf j roic in rnolecules

c.ould be rearranged and aligned to bring thenr irito if ibrous foiirr.Thers js no reason why the same thing'should not be donc in thecase of protein derived from plants.

lltet Spinning

In 1935, Professors W. T. Astbury and A. C. Chibnall suggcstcdto Imperial Chemical Industries itd., that nb.es "oufa bc madeby dissolving vegetable protcin in urea and extrudinl i l re solut ionrnrougn sprnnerets into coagulat ing baths. At that t ime I .C.I . wasengaged. in research designed to aisist in thc devclopment o[ thcworld s tess prosperous areas, with a view to finding new uses fortheir products. One of the most likely sources of veietable protcinfor libre production was ground-nuts, which g.oil o. a sttplcproduct in many of the hot, humict regions of ilte wort<t.

Groundnuts (peanuts, Monkey nuts) irc usea in large quantitiesas a source of the arachis oi l required for making nrargarine.The meal remaining after removal of the oil "onlin, i- higt,proportion of protein. This protein was regardcd as a potcntiaiiysuitable source of vegetable protein fibre.-

t 3 5


Experintents were cnrr icd out, and a process was developed fornraking the pcanut protein f ibre which becante knorvn as.Ardi l ' .( - fhe f ibrc was l l rst nrade at Ardeer i rr Scot land.)

I ly 1938, plans wcrc nrade for pi lot-plant product ion, but thcwar held up further progress. Experimental production of 'Ardil'

eventual ly began in i946. Conrntercial manufacttrre fol lowed. afactory being bui l t at Dumfr ies. By I 951 'Ardi l ' was . in product ionat the factory, rv i th a planned output of 9 rni l l ion kg. a year.

Product ion of 'Ardi l ' rvas suspendcd iu 1957.

No tcIn the sect ion rvhich Iol lows, information on grourrdnut f ibres isbased upon the f ibre 'Ardi l ' , as i t was whcn product ion ceasedin 1957 .

PII.ODUCTION

Ilarv I \hlcr iul

Croundnuts are the seeds of a sub-tropical annual plant, Aracl isI typogaca 1., which is cul t ivated in lndia, China, West Afr ica,Bornco and the southern statcs of U.S.A.

- ' fhe,groundnut plant grorvs to a height of about 26 crn (10 in).After fert i l izat ion the stalk of the ovary elongates, pierces thcground to a depth ol 25-75 rnrn ( l -3 in), and the seed-podsripen unclergrou nd.

After harvcst ing, the nuts are shcl lcd or dccort icatect. The reclskins are then removed Irom the shcl lcd nuts, togcther withforcign matter such as snral l stones and nai ls.

The nuts, lvhich contain about 50 per cent of oi l , are crushedand pressed. Sorne 80 per cent of the avai lable oi l is squeezed out,leaving an oi ly groLrndnut meal which is reduced in breaker rol lsand passcd through {laking rolls. The thin flakes pass via a seriesof buckets on an endless chain into an extract ion plant. As theypass through the plant, the buckets of meal are subjected to athorough washing with solvcnt (hexane) which removes therenrir inder oI the arachis oi l .

Thc extracted nreal is heated under low pressure in steam-jackctecl pans to renlove residual solvent. l t is then cooled,screcnecl, rveighed and bagged.' fhis

special techniquc lor relnoving oi l f ronr groundnut mcalwas dcvised to provide protein sui table lor l lbre product ion.

t 3 6

T ' r , t r t r - l r - I ' I r I --T

A : N A T U R A L P O L Y M E R F T B R E SExtractcd nreal-produce<l by the normal cxtract iorrIn rne product ion of arachis oi l is subjccted totemperature, which leads to a deterioratloi, oi1fr"the protein.

proccss uscdtoo high a

propcrt ics ofAbout 50 per cent of the extracted mcal consists of protcin,the actual prorein content vary.ing u".oiAlilg tl"iLc nraturity ofthe seeds and the conditions und"i which ttii nr. g.o*u.

,, lr.--rro.ynd,ru1 protcin is cxtracte<I f.; iii;',,;; by dissolvingIt ln caustic soda solution, the residue after citraction bcing avaluable catt le food which.,containl-*;;-3 i"r"".n, nirrogcrrfrom. glutel ins insoluble rn the caustic soda.Acidification of the nro-tein sotrtion pr""ipitatcs thc proteirr,which is rhe raw materiil rro'n *r,iiri nrir;[''.,;;;;

Spinning Solution

Croundnut protein dissolvcs. in lqrrcous trrcn, an.rrnonir, cnuslicsod., and solutions of -clctcrgc.is

-,r. i i"Lr" ' , , l tyf bcrrz'rcsulphonare. In rhe manufa.tu;;-; i n;;; j i i r , ; sorurio's o[caustic.soda werc used to dissolve t ir" pr"i . i".

"" ' '

. A,.solutjon of grounclnu_t protein in <j i lutc caustic soda solutior.ris allowed to maturc un<tci controllcJ """afil"lu for 24 hours.During. the maturarion, the viscosity-"i- i l ' : ; i ; , i"n incrcascs,probably as a result of the.unwindi,ig "f i"itr.j'"r coiled nrolc_:ul:r, gf globular protein.. At.the cnj oi Ur"-,*t i"^t ion pcriod,a stable solution of suitable viscosity n,iJ,pi,, ,r i ,u"irrnructcrist. icshas been prod ucect.- ̂ The solids content of the protein solut.ion is betwccn 12 ancl30 per cent.

Spinning

l l :_:: l : j i" l of groundnut. protcin is I i trercd and punrpc<r rosplnnerets, through which it . is extruclcd ot-.on.i"nt ratc intoan acid coagulating barh. Thc .pin,r" i" i f i"f"r""r" ' typically ot0.07-0.10 nrnr. diamcter.The coagr:iat ing I iq uor .consists of a solution con tainingsulphuric acid, sodium sulphate ,"a ^.,*iu,,rl,'".i,"rr.tanccs. It ismajntaincd

.at a remperaturc bctwccn rz ., i , i ' io; i . '^,,1:

,n.. t l lam€nt is being spun, i t is strctclrc<l to incrcasc thcarlgnrnent of thc protein morecures. l t coagutals-to a f iramentthlt is wcak and f labby whcn wet, an<l brit t lc whcn dry. At this137

r F ' r ' l [ ' r ' r - - - T

I l'''l FlH A N D B O O K O F T E X T I L E F I B R E S

stage, the f i lament dissolvcs easi ly in di lute sal ine solut ion andin di lute acid and alkal i . After leaving the coagulat ing bath i tis treated with formaldehyde to harden and insolubilize it (see

Casein Fibre), and i t is then dr ied and cut into staple.

PROCESSING

Scouring

Wet processing involving the use of alkali should be carried outat moderately low alkali concentration and temperature. Wool-type scouring condit ions are suitable, and processes such as kierboi l ing should not be used with fabr ics containing groundnutprotein fibre.

Bleaching

Sodiunr hypochlor i te and sodium chlor i te cause dcgradat ion andshould not be used. Hydrogcn pcroxide is the preferred bleachingagent.

Dyeing

Groundnut protein fibre may be dyed with dyestuffs used fordycing wool, but the di[Ierences in protein structure result indiflerent

'individual characteristics. In general, the allinity for

dyes is higher than that of wool.

STRUCTUI{I] AND PROPERTIES

Finc Struc lurc and Appearance

Circular cross-sect ion. Smooth, s l ight ly s t r ia ted sur face.

Tcnacity

62-8.0 cN/tex (0.7-0.9 g/den).

lcns i le Strength

B-12 kg/mmz ( l 1 ,000-14,000 lb / inz) .

Elonga( ion

40-60 per cent dry; 80 per cent wet.

1 3 8

E T E F . F F F I ' ' 1 I :


Modulus of Torsional la-gidilyI .3 x 10to dyne/cmr.

Specifc Gravity

r . 3 1 .

Ellcct of Moislure

Regain.: 12-15 per cent (depending upon type).[xnands slightt y when wet, irying

-to iiieiriai ilrn.nrionr.'Heat of wett ing : 26.6 cal. lg.-

"

Thcrmal Properties

Docs not soften or nrel t on heat ing. Chars at 250,C.

Flanunability: less flammable than wool.

Chcmical Propcrtics

Acids...High resistance, similar to wool. Withstands carbonizingcondit ions.

Alkal is. Poor resistance, simi lar to wool.

General. Similar to wool. Degracled by so<lium hypochlorito anctsodium chlorite bleaches.

Ellcct of Organic SolventsC ood,, r.es.ista nce, similar to wool. May bc dry cleancd without

Insccts

I lesistant to attack by moths.

Micro-organisms

High resistance to mildews.

Rcfractivc Index

| . 5 3 .

n t

r39


Notc

Crounclnut protcin f ibrcs are gencral ly sinr i lar to woo[ in thatthcy are protein in structure. They do not have the rough scalysurlace of wool fibres, and do not undergo felting in the waythat wool does. A comparison of propert ies of groundnut proteinf ibres ( 'Ardi l ' ) and wool is given in the table below.

Croundnut meal provides a mixture of proteins, the composi-t ion of thc protcin in the f i lamcnt dcpcnding on condit ions undcrwhich they are produced.

Groundnut protein molecules carry many side chains, and thcycannot pack so closely together as the rrolecules of s i lk. Ground-nut protein yields a rclat ivcly weak f ibrc, which is much morcsensitive to nroisture than wool.

COMPARISON OF PROPERTIES -GROUNDNUT PROTEIN FIBRE AND WOOL

Property Groundnut Protein WoolFibre ('Ardil')

Tensi le Strength (kg./mm')Elongat ion at Break (per cent)Young's Modulus (kg./mm'� / I per centext 'n. , at 100 per cent ext 'n. per min.)lv lodulus of Torsional Rigidi ty

(dyne/cm'�)Specif ic GravityRcgain (per cent)FIeat of Wett ing (cal . /9.)Refractive Index

B-t 040-60

1.65

1 . 3 x l 01 . 3 I

t2-1526.61.53

12-2030

) 4

l . l x 1 0I . J J

l 526.9

1.55

CROUNDNUT PROTEIN FIBRE IN USE

The outstanding character ist ic of groundnut protein f ibre is i tssoft, wool-like handle. When it was in commercial production,'Ardi l ' groundnut protein f ibre was cost ing about half as muchas wool, and it was used largely as a diluent fibre which providedwool- l ike character ist ics at low cost. I t was used almost ent irelyin blends, nrost ly with wool, but also with cotton and rayonstaple.

140

; l n , l r " - l f I r - l T I r I ' I r I r I '

I r-l

A : N T U R A L P O L Y M E R F I D R I ] S'Ardi l ' /wool

blends were used_ for swcatcrs, blankcts, undcr_wcar, carpets ancl felts. Blcnds with cotton wcic ,rs.cl fo. sport.shirts, pyjanras, dress fabrics., ald blencls witn iayon'for costunlcand dress fabrics, tropical ciothing, .p"it. ,lrlrrc'i"a carpers.

protein are able to uncoil and straightcn r f, .n-r." lu"r- 'ou t. Dtrr ingthe matura t ion. period, the viscosity-or rrr" ," i i i i io, i incrcascs asthesc long molccules becomc associated into t,, i t .r nrolcculargroups.

I lctween 1948 ancl 1957. a protcin-f ibre ,Vicrra, was in productionin.th.e U.S. It was maclc fio- z"in, tfr" p.ot"in'o?" _oi.".'Vicara' was man ufacrure<t. by.,tlie nl ril "i":'ir-iina CtrcmicalCorporation of Richmond., virginia, t;; plil"i;;a,"u n, Tof,-ville, Connecticut. productron was suspencted in 1957.In the natural stale, zein .moleculcs nr" *i i". i-up' in thc forrnrypicr l .of a globutar prorcin. r i ;br; ; i ly; i , i , ' t , l ' *1, , , , , i , , ru nlibrc, thc nrolcculcs nrust b,c uncoilccl to 'p.

i , , , i i ' i f , . ,n to nl igrrthemselves beside one another. ffli" l.- a"ln" "frv

iissotving tlrezein in caustic soda. whcn trr" nc u iiulizon:In-oirtlll' n.i.l g.o,,p.in the protein ntolccule destroys the attraction b"i*.,. , acid anclanrine groups. The molecules aie rhcn "bl" i;;,r;;ii';nd associarcl:g::l:,._t"

the posirions or "riennr"nt'"ricis?;; ror fibrclorntat lon.

ZEIN FIBRE

INTRODUCTION

PRODUCTION

Rarv Malerial

Corn_ meal is extracted with rsopropyl alcohol, whiclt dissolvcso-ut the zein..After evaporat ion of t t re "1""1"f ,- t f i i , ic in is obtaincdas a pale yellow powder.

Spinning Solulion

The zein is dissolvecl in caustic socla solution, rvhich is thcn3,*::1 -"*" l::.::il.g. Tr," ."i"ti",i-i, -

"ir";il il';;,;J";;:,_1l9i"S for,several hours, when the coilcrl ,rrof..r.,f.r'"f ,ji

I

t 4 l

I

II

IIIIII

-l

.F.NF.NF.NF F. I NF.F.F}}}I I A N D B O O K O F T E X T I L E F I D R E S

Spinning

When the zein solution has reached the correct viscosity forspinning, it is pumped to spinnerets and extruded into an acidcoagulating bath containing formaldehyde. The filaments arestretched, and some crossJinking takes place by reaction betweenthe zein nrolecules and formaldehyde. After stretching, the zeinfilaments are subjected to further hardening in fornraldehyde,which creates additional crossJinkages between the zeinmolecules. The lilaments are washed, crimped, dried and cut intostaple.

PROCESSING

Dyeing'Vicara' could be dyed w.ith most of the normal woolwith alkal ine vat colours. I t had excel lent resistanceand t l re caust ic sodzr used in alkal ine vat dyeingdeleter ious effects.

'Vicara' withstood hot rvater and could be dyed at

SI 'RUCTURE AND PROPERTIES

dyes, andto alkal i ,had no

the boi l .

F ine Struc lure and Appearance' V i c a r a ' w a s m a d e i n 2 . 2 , 3 . 3 , 5 . 6 , 7 . 8 , 1 7 c l t e x ( 2 , 3 , 5 , 7 , 1 5den) , and in s tap le l eng ths o f be tween 12 and 150 n rn r (% and 6in ) .

The individual f i laments were almost circular in cross-sect ion,and resembled smooth transparent rods. They were cr inrpedmechanical ly. The colour was golden yel low.

Tenacily

10.6 cN/tex (1.2 g/den) dry; 5.74 cN/tex (0.65 g/den) rver.Rat io rvet/dry: 54 per cent.

Te nsi le Strength

1225 to 1365 kg /cn rz (17 ,500 to 19 ,500 lb / inz ) .

I i longal ion

25-35 per cent dry; 30-45 per cent wet.

t42143

A : N A T U I I A L I ' O L Y M E R F t B R E Slilaslic Ilccovery

.96 per . .cent at Z per ccnt e longat ion; g0 per cent at 5 pcr ccnte longat ion.

Speci0c Gravi(y

1 .25 .

trllcct of MoislureRegain l0 per cent.Moisture. imbibi t ion 40 per cent.Jwcl l lng tn water 20 per ccnt.

Tlrcrmal Propcrlics

Ceneral ly simi lar to wool.deconrpose at about lg5"C.

Flantnmbility : did not burn

EIIect of Agc

None.

,ilil-jTiffirastic, but began to

easi ly.

Ellcct of Sunlight

Sonre deterioration on prolonged exposure.

Chcnrical Properties

A ci d s. lJtghly resistant.

AIkalis. Less sensirive t" ilf.lll than are wool and othcr proteinfibres. Cold solutions had little "ffe"i. ffot-roiution. of .t.ongalkal i caused deter iorat ion.

General. Simi lar to other protein, f ibres. Goocr resistance to l 'ostchemicals encountere<l in normal usc.

Eltcct of Organic SolycntsInsoluble in most solvents. ancl could be dry clcanecl withoutdi f l icul ty.


Insccts

Not attackcd by nroths or othcr insccts that attack wool.

M icro-orgurrisnrs

I{esistant to nr i ldews and bacter ia.

Note'Vicara'had an attract ive handle, and did not cause any irr i tat ionto the skin. I t had cxcel lcnt hcat- insulat ing propert ies, and macleup into f l rbr ics that werc as warm as wool.

The ntost signilicant features of 'Vicara's properties were itsconrparat ively high wet strcngth and i ts rcsistance to alkal is. l tcould be washed readi ly and without di l l icul ty.

ZEIN FIBI{E IN USE

SOYA.BENN PROTEIN FIBRE

INTRODUCTION

'Vicara' o[ Ierecl an unusual conrbinat ion of attract ivc propcrt ics.I t was softer than wool, and made up into fabr ics as warn aswool. I t was resi l ient, and gave fabrics a luxurious feel.

The high moisture absorbency made 'Vicara' especially attrac-t ive as a clothing f ibre, and i t could be washed ancl l ronecl withoutdi f f icul ty. I t did not fc l t .'Vicara' was uscd most ly in blends with cotton, rayon andnylon. l t brought excel lcnt handle, resi l icnce, softnlss andrvarnrth to the mixturcs. l r4ixed with wool, .Vicara' increased thewcar by reducing the tendcrrcy to fray.

_ Blends containing 'V. icara' were uscd in sui t ings and clothes,knitted goods, hosiery, blankets and pile fabrics. The ,Vicara;inrproved crease-resistance and dimensional stabi l i tv of thegarrnents.

Soya-beans havc been one of the staple foods of Orientalcountries for thousands of years. They are rich in a protein whichresernbles casein.

In Aurer ica, soya-bcans are now cult ivated in great quant i tyas I sourcc of cdiblc oi ls and protein. Many attempts have bccn

144

' L t l t l r l


rrrade to spin this protejn .into useful fibres. Thc Ford lr{otorpomna.nf .!1 pioneered in this ficltl; proju"iion-fry rhis conrpanybcgan in 1939 and reacherl more than ttrree tons i'wc ck by 1942.The fibre was used for making "r; ";i;;[t-.; ]ro<tucrion wastaken over in 1943 bv the Drackeu p;;r;;a;U. ot Cincinarri,but stopped after a fiw years.

PITODUCTION

Itarv Matcrial

l:11-!"""r have a high protein.content (about 35 per cenr), andtney are grown in abundance_.in U.S.A. and cast'crn countrics.They provide a cheap and readiry """ii"-ur" ,""ii" of protein forfibre procluction.

-. The beans are crushed,.and the meal is extractcd with sorvcnt(hcxa.ne) to remove thc oil. Tlre prot;i;ls'Jir"f*,r out of rhc::,]lll"irg. nrarcrial by diturc. ,i,triuiu ,rrpiiit." rorrUon, nntlrccovered by acidi{ication of thc solution.

Spinning

Soya-bean protein is dissolved in caustic soda solution, and aftcrbcing filtered and ripcned .the solution is nrrn;;;';" spinncrcrs.The jets emerge inro an acid coagular ins di i l , ; ; ihc f i tanrcnrsare stretched, hardened, washed, ar.iea aiA cut'inio staple.


Tenacily7 cN/tex (0.8 s, /den) drv;2.2 cN/tex (0.25 g/t tcn) rvct. I lat iorve t /d ry : 3 l pe r ien t . '

Elongation

50 pcr ccnt.

Ellect of Moisture

Regain l l per ccnt.

NoteSoya-bean fibres werenroisturc to thc cxtcnt

low strcngth, ancllosing 69 per ccnt

145

wcrc sensit ivc toof thcir tcnncity

ofo f

'rr, rl r - F E li E F E F, E l'''i E f''i f'1 F.FI I A N D B O O K O F T E X T I L E F I B R E S

when wet. They were general ly of poor qual i ty comparcd withother regenerated protein fibres, and had little more than cheap-ness and avai labi l i tv of raw mater ial to recomnrend them.

COLLAGEN FIBRE CMARENA)

INTRODUCTION

A protein fibreCermany, underend of 1959.

PRODUCTION

was made by Carl Freudenberg K.G.a.A.,the name 'Marena'. Product ion ceased at the

hides. Theby hydro-

dyed.

'Marena' was a collagen fibre, produced from splitsplit hides were chopped, treated with alkali followedchlor ic acid, washed, ref ined and spun in solut ion.

The fibres were dried and tanned. They were dope


Spcci l ic Gravi (y

1.32.

Ellect of Age

N one.

Eflect of Sunlight

None.

E{Iect of Acids

Resistant.

[ficct of Orgnnic Solvents

Resistant.

Insects

Cood resistance.

Micro-organisnu

Good resistance.

146 t47

A : N A ' T U R A L P O L Y M E I I I I I I ] I r I : S

COLLACEN ITIBIIE IN USB-'Marcn l '

was s im i la rstabi l i ty a ncl exccl lcnt

I t was used Iargely

to. horse hair . I t l ra<l good dinrcnsionir lrcststal lcc to dry-clclrni trg solvcn ts.as brush fi bre.

MISCELLANEOUS PIIOTEIN FII} I{ES

Wherever there is a source of cheap, waste protcin, thcrc is lrpotent ial text i le f ibre. There arc two such sourccs of i r rr lustr ial

T"'^"#ltB#i:T[.*-",?, j,.,?i;,*]i"*l;]il*ll{li;:'oXi1,31

rhe great egg-arllng pil,i;;';;;-;ii,"". ]. i" chickcri

... 11 t l . case of the egg alt,umin, the protcin ntolcculcs arc foldctlrr 'and globurar' The probrcrr 'r i . to , i ,rroi. i"t i i ."t '"", i bring trrcrrrirrto thc extcndccl, f ibrc-fornring statc.Feather protein morecur".^^r; ;i;;;ly cxrendcrr, but arc rrighrycross-linked into a nctwork. structure. Hcrc, it is a "as" o[ brcak_ing down the cross-l inks wirhour ;";; ; ; ; ; i i ,"",, lo]."urn, .t ,r iu,themselves.The sanre process has becrr uscd -expcrirnen tally for tlringingboth these proreins inro a.spinnabi; f"r l i 'nig' i ' r icattrcr protcin

:i",1,$,:ll, i,,iil::..,:,li;J,,t:l,xll1i""i'il:1"$;tfiff .lli Imolecules in the extcncled posit ioi r" i i f- irr.v fr""" ' fr""." s;:un anclthe f ibrc coagurated. The detergcnt is tr,",r reinovJ ancr wirshcclaway,,tcaving rhe cgg or r."orr," i pioi" i i i ' ; ; i ; ; ' ; ; i i oI cxrcrrdcrland al igned nrolecules. Al

:1iiH iif: " :,lt''i ;iJ' :: ;i :?. I [ "i;:l' ;[", :l:: i ;i"1" lii],:li

_ Other regcneratccl protcin f ibres havc becn nrade in this wayI ronr gclat ine and si lk waswilr no <roubt nna o pru"o'1,"i ill',:ff:i'.t?"sontc

o[ thcsc nbrcs


4. MISCIiLLANEOUS NATURAL POLYMER FIBRtrS

ALGINATE FIBRES

INTRODUCTION

In 1883 an Engl ish chenrist , E. C. Stanford, discovered thatcommon brown seaweeds contained a substauce which served apurpose simi lar to that of cel lulose in land plants. This substance,now cal led alginic acid, is a polymer of d-mannuronic acid ofmolecular weigbt in excess of 15,000. Its structure is as follows:

cooH

| | ./i -r r-r\r-/ A \.,/"\.. /- \ OH OH,/ ' ) . .7-

\ f l / n t 1c - cr l

H H

l - l l l

t t/ i Y \ l i

/ OH Oll\r/

\'i ./-\n/IcooH

ALGINIC ACID

Alginic acid accounts for onc third or nrore of the dry weightof many specics of seawecd, and is available in virtually unlimiiedquant i t ics in the mil l ions of tons of weed that l i t ter the world 'sshorcl ine.

Whcn alginic acid is treated with caust ic soda i t . is convertedinto i ts sodiunr sal t , sodium alginate. Sodium alginate is solublein water, forming a very viscous solution, and the alginic aci<!present in seaweed may be extracted by treatment with causticsoda or other alkal ine solut ions. Alginic acid is precipi tated whcnthe sodium alginate solut ion is acidi f ied.

_ The,molccules of alginic acid and i ts sal ts arc long andthreadJike, arrd are ablc to al ign themselves alongside oneanother in the manner charactcr ist ic of f ibre-forrning substances.Many attempts have been ntacte to produce comnreicially usefulfibres front alginic acid itself, and from its salts.

148

6 1 ' - t F - l ' L I 1 t t

A : N A . t . t r R A L p O L y l t t E R r l l l R E S

A. success[ul devclopment of alginic acid f i t : rcs wus cirrr ict lout. by Prolessor J. B. Speakman of Lceds Univcrsity, U,lgf,i,"i,dur ing World War I I . Coarse nrononlarnci i is

- 'of chronriunr

alginate wcre f i rst proclucct l . They werc grccrr i r r colour, andwcre manufactured in sorne quant i ty foi usc in canroul lagcnctt ing.

In the course of this work, Spcakman and his col lcngucs alsonrlde mult i { i lan)eut yarns of c i lc iunr alginatc. ' l .hcsc

wcrc o[al tract ive handle and appcarance, and werc of about thc srnrcstrength as viscose rayon yarns when clry. 1'hcy lra<l thc ad<lc<ladvantage of being f lanrcproof. Unfortunrtely, c l lc iunt alginatcyarrs proved to be readi ly soluble in wcakly arkarine sorr i t ions,inclut l ing soap arxl water.

1'his sensit iv i ty of calcium alginate l ibres to rvcakly alkal inesolut ions was a serious drawbaik to the dcvclol .rnrcnt o[ thcscf ibrcs for gcrreral comnrcrcinl usc. A fnbric rn,r ,rc i ror 'cnrciurrrl lg inatc f ibre woukl c l issolvc in a scouring blr th; u calciur lalginate dress might disappear in thc wash tu6., Many ai lcmpts l ravc bccn nraclc to spin f ibrcs frortr othcrarglnate satts, and from_ alginic acid i tscl f , in thc hopc ofobtaining fibres that would 6c suitablc for nornral textilc usc.

Alginic acid fibres are evcn nlore rcadily dissolvccl irr dilutcalkal i than are calcium alginate f ibres. Sonre nr" inf f i . alginatcs,howevcr, are suflicientry relistant to alkali to witrisiand Iaundcr-rng_treatments, and beryl l ium, chront ium ancl alunt iniunr alginatctrores,. l n^. part icr.r lar, have shown somc pronrisc. Alunrirr iunratglnate l rbres, Ior example, are washablc. l lcryl l ium alginafcf ibf . : of . . part icular ly stabic, but t f ' r . i , "ornui i i " iat value isrcsrrcred. by the toxici ty of beryl l ium and thc br i t t lc 'css of thcIrDres. chronrium alginate f ibres are restr ictcd in thcir possiblcappl icat ions by their green colour.. As in the case of v iscose ancl other watcr_sensit ivc f ibrcs,improved resistance to water pcnetration nright bc cxpcclccl frorrrcrossJinking treatments. Thc alginic acid r iolcculc i ras rcacl ivcacid groupings which coulcr ue uscd to fornr "ro.Jinr.r, arxr nxrr.rytechniques for crossl inking alginatc f ibrc nrolcculcs havc bccn: l i l l : l :

CrossJinking. rnay be carr icct out, for c iamptc, wirhrormaldehyde and resins, or with hcxanrethylcnc di isocyantt tc.

As yet, i t has not becn possiblc to procl trcc an algir i l tc f ibrcsuita.b.le for large scalc nianufacturc an<l fo. ,sl in nornraltcxt i le appl icat ions. Calci trrn alginatc yarns arc, l row"vcr, rnlnrr-

149

t [ ' l ' t ' t

i . n . - - | : - . - n . . . . - . . - - - lH A N D B O O k

factured on a modest scalewhich solubi l i ty in weaklyeffect.

PI{ODUCTION

O F T E X T I L E F I B R E S

and are used asalkal ine solut ions

Ilarv Malcrial

Seaweed is dried and milled to a line powder, in which form itmay be stored without undergoing bacterial attack. The first stcpin the production of fibres is to convert the alginic acid in sea-rveed into sodium alginate. This is done by treatment of thepowdered weed with a solution of sodium carbonate and causticsoda.

The solution of sodium alginate is allowed to stand, and theundissolved constituents of the seaweed form a sediment whichmay be removcd. The solution is thcn bleached, and sodiunthypochlorite is added to prevent bacterial attack.

Alginic acid is precipitated from the solution by acidificationwith hydrochloric acid, and the alginic acid is purilied and dried.

Spinnirg Solution

The alginic acid is neutralized with sodium carbonate, formingsodium alginate. This is made up into a solution containingabout 9 per cent of alginate, which is again sterilized and filtered.

Spinning

Sodium alginate solut ion is wet spun into a coagulat ing bathcontaining calcium chloride, hydrochloric acid and a smallamount of surface active agent. Tho jets emerging from tbespinneret are coagulated into lilaments of calciun-r alginate. Theseare brought together, washed, oiled, dried and wound.

PI{OCESSINC

Dyeing

Basic and direct dyestuffs may be used for dyeing alginate fibres.

Rcmoval of Yarn fronr Fabric

Alginatc yarns are uscd prirnarily as rcmovable linkages, e.g. inthe production of hosiery. Thcy may be removed fronr the fabrics

speciality yarns inis turned to good

t50 l 5 l

A : N A T U R A L P O L Y M E N F I B R E S

by washing in di lute solut ions of sodium carbonnte or sequcstcr-ing agents such as Calgon.

Coods should have sul l ic ient freedonr of movernent to cnsurclhat the dissolving solution reaches the alginate threa<Js. .fhcfollorving treatments are recommended:(a) Alginate with Cotton, Viscose Rayon, Lincn or Nylon: 20to.40 minutes at a temperature of at lcast 50"C. (120;F.) in aDxUr contalnlng

Soda Ash 2.5 e. l l .Common Salt 5 g./1.

(b) Alginate with Wool, Cel luloie Acetato or orhcr Alkal i -sensit ive Fibrcs: 20 to 40 minutes at a tenrpcratuic of at lc;rst50'C. (120'F.) in a bath containing

Lissapol C Z g. l l .Calgon 3 g./1.Cornnron Salt 5 g. /1.

Note..Y' /ct steam may causc idcnt i f icat ion t ints to stairr goodscontaining . nylon and sirni lar l ibrcs which arc bci i rg stcanr sct.Excess moisture should be avoided, an<l when .ioiiiing occurs itmay be removed usually with warm socliurn hyclrosulphitc.

ITRIJCTUREANDPRoPERTIES

Fine Structure and AppearanceAlginate fibres are striated length_wise.appearance; in cross-section the fibrcsserrated outline.

I'cn:rcity

l4-lB cN/tex (1 .6-2.0 g/t lcn) clry; 4.4 cN/tcx (0.5 g/t lcrr) rvct.

Elongation

2-6 pcr ccnt under normal condit ions; 25 pcr ccnt wct.

Spccific Gr:rvily

t .779 .

The surface has a foldcdare round to oval with a

n l


Ellcct of [Ioisturc

Calciunr alginate f ibrcs arc insoluble in water but suf ler consider-ablc loss of strcngth whcn wct.

I hcrmnl Propcrl ies

Alginate fibres are non-flammable. They will not burn even ifheld in a f lame, but wi l l decompose to ash.

Ellcct o[ Alkalis

Calcium alginate f ibres wi l l d issolve readi ly in di lute alkal inesolut ions, including soap and water.

Ellcct of Orguic Solvcnls

No cflect.

Alginate

ALCINNTE FIBRES IN USE

'fhe sensitivity of calciurn alginate libres to dilute solutions ofalkali has been a serious drawback to the practical use of thesefibres.

Their non-flammabil i ty is a most valuable property, and hasled to their use, for exanrplc, in theatrc curtains. A really wash-able alginate fabric would be of particular appeal in this respectfor children's clothes.

The solubil i ty of alginSte f ibres in alkali has led to a numberof specinl izcd applications. Thc l lbrcs are used, for cxamplc, asstrcngth providers in ploducing loosely-spun wool yarns; thc

t52

$.�ilt

riii ii :tl i

ri! I

t , l ' I ' T

153

i l . T

A : N A T U R A L P O L Y M E R F T B N N . S

alginate f ibres are <t issolved^.away af lcr kni t t ing, lcaving a f luf lylllii-Jr.r,:n,

fabric which coutcr nor havc bcen'mal" by nonnilcalcium arginate yarn is of part icular interest in i lre rrosicrytradc. Socks are linked to_gethci ty-;-ir;';";rsiJ or orginotuyarn, production beins continuous. The socks oi. i .purut..t Uycuttingahe alginate yirn,. the ,.rnuin.- "i rr,'lrf"i, are <tissolvcdawry. Thi.s techniquc cnabres perfccl-ruJtr" io' rr"' obtained irrsocks of all types.For medical usc a calcium/sodium. alginal.c yarn providcs

:lL-{i" d3.,t: dressings and dressings which-arc hae,rnosratic, norr_loxrc and absorbabtc in the blooi srr;;; .- i i ir 'url .r in a.n,nfsurgery for plugging cavitres.

NATURAL RUBBETT FI[}RES

INTRODUCTION

Rubber is a natural polvmer o-btainecl by coagulation o[ thc latcxproduced by certain soecies of plant, "tt^ttl'iirr"r" ltrasilicnsis,the ru.bber tree which grows in iropical ,.oidn._ -'"'

_. r.: r,r raw state, rubber . is a .tough, elnstic matcrial whichsoltens. on heating, becoming

- plasti-c ,"J--J"rei_l i te. In theprocessing of rubber. it is tnei<tia ̂ il ;;j;;;lwerrul milts.This.softens the rubber, renaering ii _"r.-,ir"fr'"plastic andl1letr jestroving.the elasricity ;i rd;; ;rvrnirl'", rhe sametrme' milling provides an opportunity ro, niiiji,g oir,er nratcrinrs:ll:.-tlr.o

rubber, norably sulphur *iri.r, tnt ". i,iJ jn rh" sub-seg-rl9nt process of vulcanizalion o. "uring.-'--- .*"

When rubber has been softened uoJ',ii".O on thc nrill, it issu{Iiciently .rhernroplasric b b; ;r;i;l,t;j'l,ia"rr,lp.,t rrv tr,"usual plastics tcchniques. such as extrusion and comprcssionmoulding. If ir is then heated.in i ts n;; ' ; i ; ; ; , t l ,"" ruub., , .u.t,with the.sulphur which has. been. mixed into i t , and it scts inrts moulded shape. T'he ru.bber loses

-itr "iiir"i"pirrtici ty anrlacquires t 'e unusual elasticity ,*

- "rrf" i" i . '

'* i i i r ' url"nnir.. trubbcr.

- E - - - - - - - - - - - - - - - | : | : -


A cured or vulcanized rubbcr nray stretch to many t imes i tsor iginal length, and rvi l l return rapidly to that length when thestretching force is removed.

The discovery of vulcanizat ion in 1839 marked the beginningof our modern rubber industry. I t provided a nrethod of sett ingrubber in its moulded form, and of developing the elasticity thatwas inherent in i ts molecular structure. Even before the discoveryof vulcanizat ion, elast ic threads had been made by cutt ing str ipsfrom raw rubber. Many possible applications for these threadshad been forcseen, and attcmpts had bcen made to produce elast icf i lamcnts sui table for text i lc use. Prior to the discovery ofvulcanizat ion, however, i t was not possible to produce stable,highly-elastic filaments, and little practical progress had beenm ade.

By 1850, vulcanized rubber threads were in comrnercial pro-dtrct ion at the Manchester, England, works of Charles Macintosh.The threads were in the form of f ine f i laments cut from thin,calcndered shcets of vulcanized rubber, a technique which is st i l ltused in modif ied fornr today.

For the next eighty years or so, cut l i laments were the onlyform of rubber thrcads avai lable. They came into fair ly wide-spread use for a variety of textile purposes, including fabricsrvhich would 'give' and yet provide support. The square cross-scction threads made by cutting sheet rubber were comparativelycoarse, howevcr, and they tended to deteriorate in use. They werediflicult to incorporate into fabrics by the usual processes ofknit t ing and weaving, and were of poor colour. Elast ic threads,pr ior to the 1930s, played only a modest role in the text i le trade.

In the 1930s, a new technique of producing rubber filamentswas perfected, in which rubber latex mixed with vulcanizingagents and other nater ials is extruded through holes in a spin-ncret. The jcts of latex emerge into a coagulat ing bath to forrnf i lamcnts of rubbcr which arc subsequently vulcanized. This newtechnique made possible the product ion of round l i lamcnts invcry f inc counts, and irr v ir tual ly unl imited lengths.

In the years leading up to World War I I , rubbcr f i lamentsproduced by latex extrusion began to nrake real headwayin thc text i le industry. The old, r igid type of corset and supportgarment gavc way to the l ightweight garnrent in which rubberthreads providcd a f i rnr but yielding support.

Rubber rvas vir tual ly the only mater ial avai lablc for the

1 5 4 c t 155

A : N T U I I A L I ' O L Y M E R F I t r I I E S

product ion of elasi ic f i larnents at this t inrc, and i ts shortconringsbecame more evident as i ts use became rnoru' * i j . rpr.ad. l t wasattackcd and degradecl by oxygcn anrl by t ight; i t would not wi lh-stand prolooged expozure 'to "

elevatei i..p.."tur.r; it ,uu,attacked by oils and fars, 1nd .bl p.rrp;"tl;il it rendcd todiscolour, and some of lne vulcanrzlng agcnts usccl wcrc I jablc tostain other fibres.

^ In the 1950s, rubber fila.ments realry came into thcir orvn.Great improvements hacl b."o moJ"' in th-e qual i ty of thcthreads. They could be producccr "r *r,ii" nio',"Jn,, whicrr cricrnot discolour undulv in. use, ancl they were more rcsistant todegradation by oxygen, light and "tr,"i'"g""ir. aiini, tir", ntro,the introducrion of hioh_speccl. warp k; i i i ; ; 'madc possiblc ar.a^pid expansion.in. the-prodrrction oi "ln.ri"'f^b;l;, wirh a rwo_way stretch, and thc demand for l ightwcighf .uppo.t gantrcntsincreased by leaps and bouncts.Meanwlr i le, with thc introducl ion of nylon nncl olhcr synthct icf ibrcs, f iucr fabr ics of incrcasccl strcngth' t ."r i i i . r ivr i lablc. .1. ' is

created a dernand for rubber nlamcnts" of n"* '"-" , , , r t an<l l r ighcrmodulus, which woulcl bc suirablc fo, , l r" ' i i io jr"r ion of l ighr-weight . fabr ics capabrc ot providin! p"; ; i ; ; l - ; ; ; ;port . nubbcrrr laments met this chal lcnge with- t i rc a"velopricnt of high-nrodulus'power' threacls.' I 'he importance of whiteness in thc foundat ion garnrcnt f ic ldresulted in c.ont inuecl inrprovcrncnt in t f r is r .spcci . Ant ioxiclarrtsused in earl ier rubber l i ianrents had tendcd i f Jcvctop a pirrkcolourat ion during fabric nnist , ing anJ'w;. ' ;h; , rcact ion ofc-onstituents of. the rubber with tr-accs "f ,i;;"i;;; coppcr srlrsrn water would produce materials that tcncd io iiusc a yeilorv_ing of nylon fabrics. These problern;; .* ' ; ; i " ; iy nrodif icar ionof the ant ioxidant ancl vulcanrzatton systems.

Spandex FibresIn t l re early 1960s, a ncw type of elastorncr ic thrcad ap.pcarct l ,based upon polyurerhancs. f ir"r",y,riiitii.

-ii,-r"",ii'' n o* r nu*,.'as spandcx f ibres undcr thc F.l-.C. n onr.n.rul i , ," ' i r lc plgc xxvi),conrpeted directly with natural rubbcr thrcaris ),.r

-tt l . ,upportgarnrent f ield. And thc spanclex, nfrr.. f ' ln. i-oiuious advantagcsover rubber, norablv in thcir t .r igir* i . i l l i r"

". ir", 'rg,r,r, r, igr 'r"r.modulus, and bctter iesisrancc t" "trr l i"tr, 'p"i.p;;; i ; , , and orhcrorganic materinls. The elastic recovery of ti\c sparrclcx librcs rvas

I I A N D I I O O K O F T E X l ' I L E F I A I T E S

better than that of any previous synthet ic elastomeric l i lament,and it seenrcd at first that natural rubber threads had l.ittle futurein the support fabric field.

However, production costs of the spandex fibres have beenhigh, and rubber filaments are cheaper. Also, rubber retains someadvantages, such as a lorver rate of stress decay, which havcenablcd i t to conrpete more ef iect ively than had been ant ic ipated.

Counls

Thc count systern used for rubber threads is based upon thediamctbr of the l l lament. I t is equivalent to the number off i lanrents that nreasure 25.4 mnr ( l in) when placed side by side.I f 62 f i larnents, for exantple, make up 25.4 rnm when placed sideby side, then the f i larnents are 62s count.

In the case of a round filament, the count is thus the reciprocalof the diamcier of the f i lamerrt , cxpressed in inches. In the cascof square-cut f ihnrcnt, the count is the reciprocal of the widthof cross-section expressed in inches.

I f the f i larnent is of rectangular cross-sect ion, two adjacentfaccs are measurcd, and the width of both is exprcsscd, c.g.62 x 40s count.

NOMENCLATURE

Elastotneric Fi breNatural rubber has an unusual characterist ic in that i t displayselastic recovery through a Very high extensibility, and this pro-perty has beconre known as 'rubberlike' elasticity. Many typesof synthetic polymer also display this charactcrist ic to a greateror lesser degree; these polymers, together with natural rubberitself, are described generically as elaslottters, and libres madefrom tlrenr are elastonteric fibres.

Natural Rubber FibreThe term 'natural rubber fibre' indicates a fibre that is madcfrorn a specific substance, natural rubber, and it is therefore adescriptive term based upon the chemical constitution of thefibre.

156

It r l ' . - ; l r l r l r I r I r t r l

A : N A ' I ' U I I A L P O L Y M E I { F T I } I I E S

Federal Trade Cornmission Definition

Rubber

A nranufactured f ibre in which t lre f ibrc-forrl irrg substance i5cornposed of natural or synthetic rubber, irrcluding"the fol lowirrs:. i1.^g::t: : , ,J1), a rnanufacturcd f ibre in which thJ f ibre_forrnirr!suDsrancc. ls a hydrocarbon such as natura l rubbcr , po ly isoprcne lLl l_b_yjl , t i . lr , copolynrers oI dienes antl hyaricart_,o,is, oiarnorpnous ( n.on{rystal l ine) polyotefins, (2) a rninufacturetl f ibreln wrucn.tne ltb re-.1ornl ing sub stance isa copolyrncr of acrylonitr i leano. a.dlene (such as butadiene) conrposed of not more than)u% but at least l0% by weight ol acrylonitr i lc units(-cHr-cF(CN)-).

PRODUCTION

Ilnrv MulcrialNatural rubber is obtaincd as a latex frontI-l evea brasiliensis.

Proccss

thc rubbcr trcc,

(a) Cut Rubber FilantentsThe rubbcr. latex is coagulatc<J, ancl the raw rrrbbcr is rnixcr lwlut vulcanlzlng agents and other ingrcdicnts on a rni l l . l t isthen passed through a calender, whicli pro<.luccs a thin shcct olvery accurately control led dimensions. The shcct trray bc cutinto lilaments before or after vulcanization.

There are a number of techniques for cutting calcn<Jercclsheets into I i laments. In one process, the.unvulcanized shect iscut into a ser ies of f lat r ings. A number of thcse are placcd oncon top of the other, and the pile of rings .is vulca nizcd. ;I'hc

shectsare then mounled on a turntable, *n, l o rotat ing circular kni lcin the centre of the r ings movcs otr twards at nn irppropri l tc ratcso that i t cuts away a cont inuous str ip to fornr 'a r ibbon olf i laments.

ln another process, the calenderc<l shcet of rubber isvulcanized and then passed over two sets of c irculnr rotat ing

t57

i . . . . . . . . . . | : E ' l : - l :

rI AN D BOOK OF TEXTILE F IB I {ES

knives, nrounted on shafts, one set being below and the otherabove the sheet. Each pair of knives exerts a scissors- l ike cutt ingaction on the rubbcr sheet passing betlveen thern, producingfilanrents which may bc collected dircctly as warps, or passedbetween prcssure rollers. The rollers squeeze the filaments intoribbons in which they adhere lightly together; the individualfilaments are readily separated from one another when required.

In the or iginal technique for producing cut rubber thread,which has now almost gone out of use, calendered rubber sheetrvas vulcanized and then wrapped rouud a large drum. Asthe drum rotated, a rotat ing circular kni fe moved slowlyalong the face of the drum, cutt ing the sheet into a l ine spiralof filanrent.

'Ihis proccss produces filanrents in comparativelyshort lengths, up to 180 nr (600 f t) , and hasbeen superseded bythe more modcrn technioues rvhich produce cont inuous f i larnentsn reasur ing 1800 m (6000 ' f t ) and n ro re .

Using modern cut filament techniques, it is possible to cut tocounts as fine as 85s, and if rectangular filanrents are being madethe second dimension may be reduced even further by use ofcalendered sheets of appropriate thickness. A calendered sheet ofthickness equivalent to 115s, for example, will provide a filamento[ average thickness equivalent to l00s count.

The commercial l imit for cut f i lament is usual ly in the regionof 85s.

(b) Extruded Rub ber Filatnerts

Rubber latex is mixed witlt vulcanizing agents, accelerators,ant ioxidants, pigments and other mater ials, and is extrudedthrough glass spinnerets into a coagulat ing bath, cornmonly ofacetic acid. The jets of latex coagulate, and the filaments arewashcd, dr ied and heated to br ing about vulcanizat ion of therubber. The f i laments are thus converted into f ine, highly-elast icthreads, which are dustcd with talc to provide a smooth surfacewhich faci l i tates proccssing.

Thc cxtrusion process produces f i lanrents which arc usual lyof rourrd cross-sect ion, by contrast with thc square cross-sect ionof the cut rubber f i laments. They are strong and unifornr, audcan be spun to very f inc diametcr and in almost any cont inuousleng th .

Using this tcclrniquc, i t is possiblc to produce f i larnents tocounts as l ine as 160s.

1 5 8

Scouring

Soaps arrd detergents ntay be uset l for scouring fabrics containingrubber threads. Sodium carbonate may be usid i [ nccessary anrlno sign. i f icant harm wj l l be done. Caust ic soda should nbt bcused.

Illeaching

I lubber js attacked by strong oxidizing agents, nncl blcachingmust be carr ied out with care.. Hydrogen

-pcroxidc and hypo-

chlorite. bleaches may be usett, tire iorm.r b";ng prcfcrrctl.Peracet ic acid and sodium chlor i te rnust not bc usccl .

Dycing

Rubber f i lanrcnts arc usuir l ly colourcd whcrc ncccsslrry by t l rci.l_dj,i:-", :

f, appropriate pi gnrenrs .<Iuri ng nrix ing. lf rhc

-covcri ngyarn_ rs to be dyed, carc should bc taken not to ,se conrl i t ioni

: : , : l :1 i"ul . wlr ich mighr harnr. rhe rubbcr. I - I igh ienrpcr ir turcs,

oxlotzlng agcnts, excessive alkal ini ty and organic solvcnts rnusibe.avoided. Dyes containing "opp"i in the i rolccules aucl dycswhich are fi_xed by the addition of copp.r salts arc not rcconr_mendcd. It is possiblo to use trrem wiiriorrt harnrful ctlccts, butonly by exercising very careful control .

I'inishing

I3 ,.1t... l inishing of garmenrs containing rubbcr,should be taken to avoicl materials and c6nditions'harm the rubber, as in dyeing.

..-l-l::.::: leat, in particutar, may be cncounrcrcd irr rnauy

unrshlng processes, and this wi l l cause degraclat ion of thc rubbcryarn. Temperatures above 95.C., evcn ior short pcr iocls, nrtrstbc avoided, t l . rc maximu't pernr is i ib lc total t rcatnicr i t l i r .c at thistempcraturc bcing r hour. ' I 'hc pcrnr issibrc t i ' rc is doubrcd [ ' rcach l0"C. drop in tel l tpcr l ture.

STI{UCTURE AND PROPEITTIES

PITOCESSING

Natural rubbcr isunits arc arrangcd

A : N A T ( ' N A L P O L Y M N I r F I N I I E S

a polynrcr of isoprcnc inin t l re crs conf igurat ion; i t

1 5 9

precaul ionswhich nr ight

wlt ich thc isoprenois c'ls-polyisoprcnc.


The rubber nrolecule has a dcgree of polymerization10,000, i.e. there arc sorne 10,000 .isoprene units in the

ISOPRENE

+

} I

\ 't

H.

C H

/

H

of aboutchain.

T - r

I -'\ ./'""- |Lzt-t\ |I c H , H IL J n

POLYISOPRENE(NATURAL RUBBER)

Natural rubber; crs-polyisoprcne.

Thc ' rubber- l ike' behaviour of rubber is due to the unusualforrn of its nrolccules, which are highl y-fol<lccl. When a piece ofrubber is pulled, the molecules tend to straighten out, and if thestretching force is sustained, the nrolecules may begin to slide overone another and take up new positions. When the stretchiug forceis released, the molecules will return towards their folded state.remaining in their new positions with respect to one another.

Rarv rubber is thus a plastic material that displays elasticity toa remarkable degree. If it is heated, the molecules can slide moreeasily over one another; the rubber is thermoplastic.

When rubber is milled, sorne breakdown of the long moleculestakes place. The entangled nrolecules cannot hold orr to circhother as el lect ively as in the urrmi l led raw rubber. They are nrorceasi ly pul led apart , especial ly when heated. Mi l led rubber ismore thermoplast ic than raw rubber.

When mil led rubber has been mixed with sulphur and othervu_lcanizing agcnts, ancl then nroulded into a ncw shapc, thcsulphur undergoes a chemical react ion with the rubbcr, creat ing

160

6 1 l r l t - l t - I - l ' - I r t r l ' [ - [ r [ - t ' - l - I

A : N A T U I I A L P O L Y M E R F I l l R E S

c.ross-l inks which hold adjacent lnoleculcs fogcther.. l . trc fol<.ls inthc nrolecules allow thcnt still to be pulle<I i,ito',i"rv positions inrcsponse to a force (assunring theri are not too many cross-l inks)., but a l imir is ieachecl ot *l , i"h tf l" f lnt, iui l f no longcrpcrrnit further rnovement. lf thc stretchitrg fo.."-is now rclcasi,J,Ihe .rubber molecules return _to the pos-itions thai' corrcsponrtto the shape in whicb the rubber was vutca,iizeJ.'-

I4 ,1 -C - ,^.^./\

II

i',I

/\/v\-C-l \ . . . , \

I/ \ / \n -C-7 \ .A

IIII

/V\/1.-C-/\/V\I

/V\/\ - C -/\,^\

IIII

,\ -C - r.r..\IpoLySuLpHtDlc MONOSUI.PHtDtc cAnOoN- cAn00N

( x > 2 1

l /u lcut iza l io t t o l Rubbcr- When.natura l . rubbcr is vLr lcanizcd, t l tc lor rccnairr molcculcs arc lirrkc<t-..ct,c,' 'riciity-ii-'a,t:j,i.;;1";""i;";;i;;"."?intcrvals .a lorrg thc i r lc .gths. ' l r rc . naturc- of r t rc c io i i - i i r r t<s vur ics wi t r rl 'e condirions undcr rvrricrr vulcanizatiou

-lat"r- i ir"" i-r i i tv", i i i i ,foroexample, be polysulphidic, mono.uifiii.ii"'oi-"ni'rriirl.nrrrun cross_

Rlnge of Propcrlics

The properties of vulcanized. rubber rnay be variccl ovcr a veryrvide. range by suitable choice of vulcanization conclitions. Alightly-vulcanized rubber ryay be soft an<l po.r"rr- a vcry lowini t ia l modulus, and i t could stretch to g or 9 t inrcs i ts or iginallcngth. A highly-vulcan ized rubber, on the othcr t lnnA, nroy i rou",o TllI cross-links tying its molecules togcrhcr rhat ii is ; hard,unyielding sol id which wi l l not stretch to any not iceablc degrcc.

Rubber lilamcnts can thus bc macle to a wi<ic rangc of prolicrtyspccif icat ions, and i t is di l l icul t to gcncral izc in consi-r lcr ing rdbbcif i l lnrents as a wholc. Natural rubLer has, howcvcr, chnracter ist icpropert ies which are inlrerent in the naturc of thc nlatcr ial , andlhc inforrnat ion which fol lows rnay be of usc i rr this rcspccr.

Rubb^cr Jilamcnts may be used barc, or coverccl by othcr textilcyarns of v ir tual ly any type. The nature of these coniposite rubbcr

l 6 l

LI'. F. F. F' T F. F. F. F. F.I I A N D B O O K O F T E X T I L E F I B R E S

threads is inf luenced great ly by the nature of the covering yarn,and by tbe u.)anner in which the composite yarn is constructed.'fhe

infornration on propcrties relatcs only to the rubber {ilan-renti tsel f , the term 'rubber ' being used always to relcr lo vulcnnizednatural rubber.

Fine Slruclure and Appcarnnce

Rubbcr f i laments are produccd usual ly as cut f i lamcnts of square(or sometimes rectangular) cross-section, or as extruded filamentsof round cross-sect ion.

The count of rubber f i laments ranges usual ly from 30s to 125s.Composite yarns are general ly covered with two oppositely-wound spirals of textile covering yarns. The gauge of coveredyarns ranges from 0.009 in. to 0.040 in. The covering yarns maybc of v ir tual ly any text i le f ibre, including cotton yarns in countsof 100s to 24s used singly or as wrappings of 2, 3 and 4 ends,ace ta te and v i scose rayon ya rns , 110 , 133 , 167 d tex (100 , 120 ,150 den) and ny lon and po lyes te r ya rns 33 - l l 0 d tex (30 -100den ) .

l'cnsile Slrcngth' fhe breaking stress of a vulcanized rubber in tension is in theregion of 1-2 tons/ in2. (140-280 kg./cm'� . ) calculated on thcoriginal cross-sectional area. Calculated on the cross-section atbreak, i t may be as high as 15 tons/ in2.

A typical rubber f i larnent rvi l l have a teusi le strength of 385kg/crnz (5500 lb/ inz). A comparable spandex f i lament has atensi le strength of 490-700 kg/cm2 (7,000-10,000 lbi inz).

Tcnncity

4.0 cN/tex (0.45 g/den) (cf . spandex: 6.2 cN/tex (0.7 g/den).

Elongalion

700-900 per cent (cf. spandex: 700-800 per cent).

Elnstic Rccovcry

Rubber has an immediatc recovery front stress, under normalcircumstances, of 100 per cent.

t62

F . l f ' f f : f - . f : f ,

A : N A T U I I A L P O L Y M E R F I D R E SStress Dccoy\Vheu rubber is held under stretch, thc stresses set up show agradual decrease with increased tirne, as ,ir" ""t*ort of cross-l inkcd molecules adjusrs to an equi l ib i i rnl "onJi, io, i .-,Stress decay is an exrremely aiml"ii pl"p.itv' i l '_.o.u.", t.fibrcs, be.ing.very s-ensitive to test conditions and to ilre nrcthodot preparation of the samples. The follo*iu6,'tulrle showsvalucs obtained by tcsting production batchcs of rubbcr andsprndex filaments, the loads

-tr.ing m.a.urlJ'ii a]n' extension ot

1^O^,1-"-f ":nl, using a Scott LF.2 i".fi""a

-pfl,r. resrcr, thespccrnrens being first concritioncd an<r thcn prJsircicrrca to soOpcr cent, tlre values being read on ttr" s""oria-"y.i" "t loading.

Load/Extension Ratio, Rubber ancl Span<lcx FibrcsLoad at 200 pcr ccn! cxtcn.rion; p.ri

Ruhber T hread60 gaugc

100 gauge

Spandex Fibre280 denie r420 denier8.10 denicr

235267

7 1 4635600

Notcl'hese values for loa<l werercsrer, rhc .p";i,,,;;;';"i"s'ri,j,i{iji,i;;.t",i,I,,f,1"rill.:,.lil,,if ?:)uu per cent, the valucs 6ei'f rre.sa nr prcs wcre h k;; r;Jr''ffi"fl l,',tl:i,"":'il,it;T,""r",1"$t'iT,i;spcct t tcat ion fcr th is par t icrt'ro(!,rcat.t Rcscarch rt rror;or'i '],1.

propcrty courresy waturul 'ttt,i ' i 'rl,

The f igures show a much g1gn1g1 rcduct ion in the load/extcn-:,o'1,.?l1o during.thc first an"d ,..;;;l;;;;;s""riil ," rhc casc:t_lhe

spand€x f ibrc tharr in thc case of tf ,c iuLi"r. The valucstor the spandex fibre. however, ..moin t igii.i. itli'r'*orta npp.n.ro give rhe spandex f ibrc a'conside;f l ; ' ; . i l , , ;c ovcr rhc|,63

} T A N D B O O K O F T E X T I L E F I B R E S

natural rubber in this i rrrportant propcrty. I t is equal ly inrportant,howcver, that the load/extcnsion rat io should be maintainedthroughout thc l i fe of a garnlent, with thc f ibre held in a highly-stretched state.

Thc following table shows the results of further tests com-paring the stress decay for natural rubber and spandex fibres.The tcsts were made using an 'Instron' tester in a conditionedatnrospherc, the specimcns bcing cxtendcd to 300 per cent exten-sion and maintained there for the stated times. The rubbcrthread is o[ heavier gauge than the spandex so that the stressloss was measured at comparable values of stress. Samples offiner rubber thread, however, wcre tested in the same way andit was found that the pcrccntage stress loss was the satne forall counts tested. The results shorv that the stress decay for thespandex libre is about twice that for the rubber hbre.

Conrparison o[ Strcss Dccay, Rubbcr and Spanclcx Fibrcs

Strcss Loss (per cent)S p!! ", ::!!:__ - Ry b b e r T t u' e ad_

622 rltex (560 clen). 60 gauge

AltcrA l te rAfterA l t c rAfter

nl lns.m Ins .nr ins.nr ins.nr i ns.

N o lcThis compar ison of s t ress decay rvas made on an ' Inst ron ' tester in ncondi t ioncd atnrosphere, the specimens bc ing extendcd to 300 per centcxtension and nraintained there for tlrc statcd times. The rubbcr threadis of hcavicr gaugc than the spandex so that the stress loss wasnrcasured at cornparablc values of stress. Santplcs of fincr gaugcs ofrubbcr thrcad, Itorvevcr, were tcstcd in tltc sanre rvay and it wasfounrl that the percentage stress loss wfts the samc for all coun(stestcd. Corrf/ery Nstural Rubbcr Prodncrrs' Rascarch tlssocialion'

5l 0204080

46.650.253.255.286.0

z) .+

25.027.128.028.9

Pcrnmnent Set

When the load is removed lronrrccovery is almost 100 per ccrrt i f thc

a strctchcd rubber hbrc,t inrc of stretching js srnal l .

I 'Ft ,lL --l --l "-r , I r t

164

A : N A T U I I A L P O L Y [ , r E R F I N I T E S

If thc f ibre is kept in a stretched condit ion, as in the stress decaytests abovc, the relaxat ion of stress is accompanicd by arr inconr-plcte return to the original length when the hbrc is relaxcd. .l.hcanrouut of permancnt set in the c:rse of rubber l i larncnts is snral l ,and most of i t takcs placc during the ini t ia l pcr iod of strctclr ._ As would be expccted frorn the results of thc tesrs on stlcssdecay, the permanent set of rubbcr filanrent is ntuch lcss thanwith spandex f ibre. The fol towing tablc conrparcs thc twolibres in this respect. In thc cxper.imcnts frorir which thcscvalues were obtained, 25.4 cnt ( l0 in) sanrples of t l r rcacl wcrcuscd, measurernents of extende(l leng[h bcing takerr 5 ruirrutcsr f te r . e longa t ions o l 100 , 200 and 300*per ccn i l ra t l bce r t r c tn i r r c t llor t l le t intes stated ancl t l re sarrrplcs rernovecl f ror| l thc strctclr ingframe. Thus, 5 rninutes was al lowed for recovery ln 'cach casc.

Comparison of Pcrnranent Sct, Rubbcr and St lnnt lcx l r jbrcs

Extcnded Ltngtlt ( l i l . ,

100')(, Elong'n. 200y" Elong'n. 300"/,, Elons'n.Spandex Rubbcr Spandcx Rubbcr Spundcx Rnbbcr

A[tcr5 rn in . 10.40

l0 min . 10.7020 min. I I .0040 nr in . I 1 .108 0 n r i n . I 1 . 1 0

10..15 10.30r0.60 10.40l r.00 t0.45r t . l 0 1 0 . 5 0l 1 . 3 0 I 0 . 6 5

10.90 I 0.35l r . l 5 1 0 . 5 0r 1 . 5 0 i 0 . 6 5il .70 10.80I t .85 t0 .85

10.3 0t 0.3010.3510.4010.50

N olel0 inc.h -srnrp les of threacl wcre used in thcse cxpcr i rncnts, spandcx 622dtex.(560 den) and rubbcr 60 gaugc. Tt rc ; , , ; r ; ; ; ; ; ; ; i ; o f cx lcrx tcr llcngth were taken fivc minutcs iftei clongation. .i i i iol zoo and 300pcr cent ]lad been rctaincd for the tirnts ,i"tJ ""J thc snnrplcsrcrnovcd f rom the st retch ing f ramc. Tht is , - f iu" - r -nuia* was l l lorvcr lfor rccovery in cactr casi" c"iiricit,-ii,,';,;;.i"'ii;i;i;rr pntdu<.t,rt,Rc.rearc h A ssociat io rt.

Thc data show that the pcrm:rnent set of thc natur l l f ibrc isntuch lcss than that of thc spanclcx. Thus, for an ini t ia l cxtcnsiono[ 300 pcr ccnt for 80 rninutcs, thc rubbcr l r ts strctchcd fronr

1 6 5

tr . t - - . " . " - - . . -

I T A N D B O O K O F T E X T I L E F I B R E S

l0 in (25.4 cnr) to 10.85 in (27.6 cnr) whereas the spandex f ibrc

lras strLtched f ionr l0 i r t (25.4 cm) to I 1.85 in (30 cm), i .e. tnore

than twice as much. Moreover, the rubber shorvs l i t t le i t rcrease i t t

stretch after the first 5 minutes, whereas thc spandcx fibre con-

t inues to stretch as t ime goes on.This dillerence in permanent set bctween rubber and spandex

libres is aggravated at higher temperatures. The figures on pagcs

167 and i68 show tho di f lerence in heat ageirrg bchaviour of

rubber and spandex l ibres.

Modulus

52.5-�70 ke/cnrz (750-1000 lb/ inz) at 500 per cent extensiort '(cf . spanrlei : 175 kg/cmz (2500 lb/ inz) at 500 percentextension) '

Spccific Gravify

0.960-1.066.

Elfect of Moislurc

Negl igible.

Thermal Properties

EfJect ol High Tenrperarure

At tcmperatures approaching 140'C', further vulcanizat ion of

the rubber muy tak" place, causing increased hardness and

decreased strength.At temperatures of 350'C. and above, rubber softens as

molecular breakdown occurs, and then becomes hard and

bri t t le.Oxygen plays a major role in the degradat ion of rubber at

elevated temperatures.In general, temperatures above 95'C. even for short periods

should be avoided. The maximum perrnissible tirne for treat-ment during fabric f in ishing is I hour at 95'C., the permissiblc

t ime being doublcd for each 10"C. drop in temperature.

E[Ject ol Low Te,nqeralure

Rubber stiffens with decrease in temperature from about 70"C.down to - 20"C. At about - 60"C., it becomes glass-like andbri t t le. I f maintained at -25"C., rubber crystal l izes and loses i ts

clast ic i ty, but this returns on heat ing.

t66

- ' - n - ' - - , 1 - . r - . ' r . .A : N A T U R A L P O L Y M E R F I B R I ] S

Flannnbi l i ty. Rubber wi l l burn, but i t does not rcadi ly propagatefl a nre.

Spccilic Heat. 0.41-0.45.Tlrcnrrul Conductivity. 0.25-0.31 (relativc to watcr).

N 6 0FlrJ

6 s o

d

a 4 0

TIME IN I1OURS

H.eat Agcirtli, Rubbcr and Spande.r Fibres*,:l::"1.T,,:*:ing-tcii in wJrict'l rl,r"*i"It'ioo p.i ".,,l'i'"*t",,.ion *",';:::::.::! ,'-1^__y_ll:, hcarc<r io

't'0;dj)v;;;;i' iiia'rI;l'jtl,lr?,,.|,1:Research A ssociat iorr,

167

I I A N D O O O K O F T E X T I L E F I B R E S

TIME IN HOURS

I{eut Agcirtg, Rubbcr and Spunde-r FibrcsA r l ry heat ovcn agcing test carr ied out x t 100.C. at 200

B O

f / vJfoo5-

6 0o

z

t-

t 8 24

per cen tcx tcnsion-Natl ral Rublter Producers' Rcsearclt Associaliort.

Iificct of AgcIn the abscncc of exccssive heat, sunl ight, oi ls and greases; andcatalysts such as coppcr and ntangancse, the agcing effects arcvery slow.'fhe general e{Iects of age are loss of modulus and extensibility.

Iiflcct of SuulightLight has both a discolouring and a deter iorat ing act ion onrubber which is proport ional to the intensity of the l ight andthc t inrc of cxposurc.

\-t-

Y TURAL RUBEER

PANDEX

. I r " I r I

1 6 81 6 9

. F

: N A ' I ' U I T A L P O L Y M E R t I I I ] R ! S

Jn ir covcrcd threacl. thc rubbcr core is largcly protcrtcd fronlthc clTects of sunl ight.

Chcmical propcrtics

zlcir ls. N:rtural rubbcr is rcsistant. to urost iuor.ganic acids, butrs at tacked by conccn tra (ecl s u lp'u ric o.iJ l,r.f' "fr'"'o*idizing

aciclssuch as ni tr ic ancl chront ic acids. --- -"e v, v^

Mincral acids and the s,'c ry d' u rc,,.^1i,"i,i,'"tn1'ilff ,'JitllJ; i;'';1, ll:'i,jo;:l' "il:threads, causing sonre changc of shat le.

l /kalrs. Resistancc to alkal is is gencral ly good.

Gcneral. Oxygen and. more especial ly, ozone attack rubbcr,causing degradat ion wl i ichAr r l i ox i r : r r r r c , , , . ^ , , . ^ ^ - . . ^ . .1a .

made apparen t by . su r face c r .ack ing .Antioxida.rs arc incorpor.ar.,r i;,iffi;",i,ir,i"' j,lii,lll-l,i,t;

looo

900

000

700

cr 600

{L ? ' - "

3()0PL:R C.[ I.IT

Rttbbcr 7'hrcar. cotnpuris'tr ol stan.tran! artr! I 'orvtr T,rtrcutrs.' l ' l )cse st ress-st ra in t l iar ranrs

_ot DI t647 powcr . l - lc t ro; ; , nnt l DIUTAstarr ( tar( t 'Lact . ron '

rubbcr t l r rca<ls i lhrs_rrate r i ic i " . . i i , iJu nror tu l r rs oIrfrc l 'owcr Lhrcad.-Loslc-r ytrn and Lii,r.',, f),,:r',i, i 'Lil.

t r . I t I t I t I t F t , I I F F FI { A N D B O O K O F T E X T I L E F I B R E S

these will give adequate protection lor most normal textile

appl icat ions.' i tubber is attackcd by chlor ine and other halogens' I {ydrogen

p"roiiJ" and hypochloiite bleaches may be used, but peracetic

acid and socliuni chlorite bleaches must be avoided'

Copper salts cause degradation, and must be kept out of con-

tact with rubber.

EIIcct o[ Organic Solvenls

Natural rubber is swelled to a small extent by acetone, alcohols

ancl vegetable oils such as castor oil. It is attacked by hydro'

"urboni oi ls and fats. Dry cleaning f luids should be avoided'

- roo 2oo ,ui9&",

4oo 5oe oul

Stress'strain Diagram, Spandc.r Fibre ('Vyrene')

'Vvrcnc ' l l0 's count . F i rs t and s ix th cyc lcs o[ extcnsion ' Scvcnth cyc lc '

^ii;;jr;;;""1-i.i i, Listttl. ' cvclc nttci 24 ltottrs at rcst'-L(r'r'c't y(tril

and Laclron Tlveacl Ltd-

1 7 0

A : N A T U R A L P O L Y M E N F I D R E S

Insccls

I{esistan t.

Micro-organisrns

Itubber is attacked only uncler vcry warm andElcctrical PropertiesElcctr ical resist iv i ty: l .7x I016 ohrns/cnr. cubc.Dielectr ic Constant : 3-15.Power Factor: 0.002-0. L

<larnp concl i l ions.

PER CENIStress-Strain Diagram, Rublryr Thread (, Lactro,i)

:!l:..:'l:^i.lj -count. Firsr and s.ixrh cyclcs o[ cxrcnsi,,,r. S""c,rrrr::ll:',9.11:.'l.*ll rcsr. cighrri cyc-r"'iiitii z ri.i,,il'ii''Ji'*'i._|r,.u".

500

cycl cY u r nul L,uctrin" iti';;;;i ti;:

I 7 l

A : N A T U R A L P O L Y M E R

NATURAL RUBBER FIBRES IN USE

F I B R E S

Coverirtg

Rubber threads are used in kni t t ing and weaving ei ther. in thebare form, or covered with spirally-wound textile yarns.

Covering is carried out by drawing a rubber thread throughthe ccntre of a rotat ing hol low spindle. The rubber is stretchedto a dcsircd cxtcnt as i t is cnrcrging from the spindlc.

The cover.ing yarn is held on a cheese or bobbin which isnrounted on thc spindle, and as the bobbin rotatcs the yarnpasses ovcr-cnd from the bobbin and wraps spiral ly round therubber f i lament as i t emerges from the spindle.

In recent years, spindle speeds have increased greatly, largelyowing to the use of air-drag to tension the covcring yarn. Flyeror ring and travcller mechanisms were previously employed.Using the latter, spindle speeds were in the range of 5,000 to10,000 rcv./nr in. ; modern spindlcs rotate at about 20,000 rcv./nr in.

There are many reasons for covcr ing rubber threads in thisway. The covering yarn protects the rubber from l ight and otherdegradat ive inl luences, and from materials such as fats andgreases which would attack the rubber. Covering also permits therubbcr to be helcl in a part ial ly stretchcd statc in the compositeyarn, enabl ing the covered yarn to cxcrt grcater restrainirrg powerrvherr used in a support garment. The covering yarn wi l l a lsorestr ict the total stretch of the composite yarn; the rubber alonecould stretch to 9 or l0 t imes i ts or iginal length, but this isnot general ly desirable in a fabr ic.

Knitted, \Yoven and Braidcd Fabrics

Rubber threads are used on.al l types of convent ionnl equipnrentin the product ion of kni t ted, rvoven and braided fabrics.

In relatively dense fabrics such as woven webbings or braids,barc rubbcr f i larnents may bc i rrcorporated in the fabric at highextcrrsion, ant l held in the extcudcd form by the fabric structure,thus providing a fabric with high power.

In opcn fabrics, it is more difllcult to use the structure ofthc fabric i tscl f to maintain the rubber thread in i ts extendcdstate, and in fabrics of this type covered rubber threads arcconrmonly used. Thc covering yarns of the composite threadsholcl the rubbcr corc at a control lcd dcgrce of stretch whcn thc

t72

r - l . l - l t I - I -

| ' | ' I r - ' 1

A : N A T U R A L P O L Y M E R F I B R I ] Sfabric is relaxed. Cca<rva nrale,i;li""iJl[:ll'J,.!?::,,,J';:i;,,i[]i,ii:., .,1*lcontamination by oils and otfr"r'.lrgrojitiv""nra tcrials. .I.hcy

arcalso easier to control in kniuing;;?-;;,;;roccsscs.The perfornrance of al .r"rfrnlrl."nir"'..,i.,, as rubbcr inpmcrical use is influenc.,l g.îiy;;ljri. ,".r,"ill* of usirrg rhcclasronrcric threads in a pairty.eit",iO;;1";:, i i ,. abil iry of rhcstrerctred matcrial ro srrsrain'

ii; ;;; ^JJ.rî,r.r.

corclirio'sduring the lifc of the IErît"i,'".i" il."J :::ltit

is a vitallv ittrportant factor'tnatcr ials capablc or , t t t "9

lor st lpport garmcnts. are usual lyo"ri"g'tr,"l|ilioir;;"'-"?i cxten.sion of at leasl. 9oo p"r. ..înrericir,rcaJ;;;;#fi :';!if lt:l$l&",i,i;llf ll;.,11"":]i ji;at.a^srrerch of pcrhaps._I0o to zoir-pe"r 1"";"i;;;. by rrre f^bricstruclure or by the covco b r a i ns wrrc n .,r;; l'' i j L' J.'illii: +ilj iit,f".r,lft ;i,:J

f i:l;iiiniti l l rcsisrancc ro srrctchirrg wh;,,îl;.^;;,. i,"l. i i , i, pur orr, lri;:1","0".;ff

':$*J;,,.t.1,- lnusr rrrc' .;;;;,;;-;,, ro rhc bo<ry

trrat is require<t. I rorcc to achicvc thc dcgrce of corrtrol

. When the manufacturer is. dcsigning rl sul)port garnrcnt, hcarnrs ro produce o ,u"n,:j],l wrricrr rilrt ironi<.r"",i,I."i."ry thc rightctcgree of support, and wiil mainrain rti is supp6ii auring thc rifcl1'li""til'l;,'ii"ll"'ffi ,'::'lri"s.

r;;;';; tii,;;",, trre-garnreninecessary conrrol wirr'":1 ff ffil:XtJj:t

rorce is too sn]trll, theDuring its acrive l i fe. lh, , , , ; ; ;r; ;arrncnr wilI bc srrctchcdb.y body nlovernent, and. wil l rcturn w-hcn ,. lu*"J to i ts nornral

:llj:;,Ij:" rhe elasron,eric tr,."oas in ;iffi#i., JI, of conrroltc<l

. It the elastorneric nbl__1:, lr: to ,crccp, and un<Icrgo strcss<tccay wlren held un<Jer t

or ir. ini i inf . . i";r; ; , ;"f".,"n, ir nray lose a sicnif ica,,f , , , , ,o, i i i i

clcsigner wil l havc ,o ,,, ,131""-o19.during its piactic*l , ,r. . ' : i i , .

.r) the construction of i I^ t3t tt t i t loss of tcrtsiort by. t ietr lcnlr i i

.r i , .otroJ'oi l ; ; ; . ; ;";"?.^9arn)cnt' so adding to thc gencrirT

. *;.,,J:,,:";'j"' "'l' J'l"J; i,l,'j' ;L Tl #li, li j''il''.,.: ;:;:l ;i' ;,,

(l) An extension ar bre1f,?f about 600 pcr cent, ro nl low rhcthread to opcratc in the nricldlc of ir, .^tJ". l* ,r, i"s..

173

t r , T T T T T T T T I T I F , F , Fr f t l


(2) A high rat io of load to extension (modulus) for extensions

in the region of 200-300 Per cent.

(3) The abi l i ty to retain a high load/extension. rat io ufter

.ont inu., t stretcl i ing, ancl af ter being held for an indef ini te period

at an extension of about 200 per cent.

(4) Adequate tensi le strength. Very high tensi le strength is

noi nceclecl, as the fibre is never strctched beyond about half its

total rangc, ci ther <. lur ing manufactt trc or in subsequent usc. Thc

rigid fibres of the fabric act as a buller which prevents extension

beyond a certain Point.i lubber threads sat isfy these rcquirements, and in sonre respects

lrc supcrior to othcr clastonrcr ic mater ials, incl trding spandcx

fibres. The stress decay of rubber threads is generally lower than

that of spandex f ibres. Garments made from natural rubber

thrcacls retain their elasticity to a much greater extent, both

during the nrantt factur ing and f inishing processes of the fabric '

and throughout the l i fe of the garment. Thus, natural rubbcr

thread rnakes it possible to achieve tlre degree of control requiredwith a much more gent lc act ion which wi l l be retained over a

longer period.{ubbcr threacls arc general ly lcss heat sensit ive than spandex

f ibres. They rvi l l wi thstand the concl i t ions encountered in proccss-

ing without being af lected to the extent that spandex f ibres are.

lVashing

Garments containing rubbcr threads shotr ld be washed by haud

in warm soapy water, and thoroughly r insed. The surplus water

should then be squeezed out, not wrt tng, and the garments dr ied

with a rninimum of heat.

Ironing

It is general ly unnecessary to i ron garments containing rubberthreads. When ironing is cnlployed, only low temperatures shouldbc uscd.

Dry Clcaning

Special care shotrlcl be taken not to rub or stretch fabrics con-

t i in ing rubber yarns during dry clcaning. I t is general ly better

to avoid clry clcaning, where possible.

174 t75

r : N A l U I I A L P O L Y M E I I F I I ] t ( E S

[nd Uscs

Fabrics designed with rubbcr [hreat ls to int l ] rovc thc t i t otgarnrcnts or to providc support, arc rnarlc in gi" , i t i iu.rr i ty. f i i:'.::g,ll'-"_lllror.rrialc .trqc of.rubbcr yarn ancl issociarc<t tcxritcs,a wlde range of fabr ic handle, f ront rclat ivcly st i f f bat istcs anrlncts. to soft and supple swlmwear ancl unclcrwcar fabr ics can bcobtaincd. Over the wlrolc rangc, thcse labr ics pi"" fJ. cxccpt ionulconr fort .

1'he. typc of garnrcnt for which rubber thrca<ls arc uscd arcas fol lows :

End-Usc l;al) ricsCorsctry

,Sw.im,'vcar

I :ootwear

Surgical hosicry

Men's and Chi ldren'sHosiery

Ladies' , Gents' andChi ldrcn's Undcr-we ar and Outerwear

Wovcn bat istcs, sat ins, brocirr jcs anrl lcnoswil . l r rubbcr yarns as wcft .Knit ted garments (rol l -ons, ctc.) .Narrow wovcn and brai t lcd f l t r ics rrscdIrs Ir inrnr ing.Wa_rp-loorn knit tcd clast ic ncls urrd laccswith rubbcr yanr as wi l l p.Wovcn bat istcs, jacquards anct s:r l ins rvi l l rruDDer yanl as wc[t .Knit ted garnrcnts and fnbrics.I luched elast ic labr ics nradc by scwingrubber yarn on to thc t n"t oi , i . igiiwovcn fabric.

Woven clast ic fabr ics for borrcl i rrg rvi lhlcather to give the elast ic izcd icathcirvhich is wiclely used in wonren's footrvear.Knit ted surgical stockings, anklcts, ctc.R^ubber yarn is kni t ted or lai<J- in thc topsof nrcn's and chi lc lren's socks to nrai<cthcm scl f -support ing.Rubbcr yants arc usc<l in nrany di f iercntways ei ther to pcrfonn the fr inct ion ofgarnlent support or to rrr l intairr garrtrcntshape. Rubber yrrns arc r lso ur. i " i t "n_sivcly for th_c ruching of al l typcs ofnglct nlatcnals uscd in l ingcr ic, drcsscs,gloves, etc.

Most of the fibre-fornting substances nrade available to us byNature are organ.ic matcrials, in which the element carbon formsthe backbone of a long polymer molecule, as in cellulose and theproteins. There are, horvever, many naturally-occurring inorganicsubstances which are capable of being formed into fibres, andsome of these have beconre of commercial importance. Theyinclude nrany minerals and mixtures of the si l icate type.

Fibrcs are spun from a varicty oI silicate-type minerals andmixtures of minerals, including basalt , wol lastonite, dolonri te/claynrixturcs, etc. Thc fibres produced fronr thcrn are gcncrallymixtures of s i l icates, e.g. calcium, aluminium and magnesium.

NOMENCLATURE

I I A N D A O O K O F T E X T I L E F I B R E S

SILICATE FIDII.E,S

Fibres spun frorn mineral si l icates or rnixtures of mineralscontaining si l icates.

INTRODUCTION

Ivl ineral silicate fibres are included in various commonly-usedIibre groupings. They are inorganic fibres and nincral [ibrcs.Their rcsistance to high temperature puts them into the /rglrI e tn pe rot u re fbre classilication.

These fibres are usually described as nineral silicate fibres, atcrm which indicates that they are si l icates of natural or igin, asdist inct l rom si l icates which are made synthet ical ly, e.g. glass.

PI{ODUCTION

Ilarv Matcrial

Basal t , wol lastoni te, dolorn i te /c lay mixturcs and the l ike.

Producl ion of F ibrc

Thc processcs used in nraking si l icate f ibres vary in detai ldcpending upon the nature of thc mincrals used as rarv materials,but the general principles are alike in most cases. The rawmaterial is nrixe<l with coke and fed into a form of blast furnaccthrough which an air jct is blowrr. ' fhc cokc burns, rclcasingheat that nrclts the chargc of si l iceous raw material. The ntoltcn

| - 1

\, l

176 t t t

A : N A T U R A L P O L Y M B R T t B R E Srrr i rrcral f lows to thc bottom of thc furnacc, fronr which i t crucrgcsto nreet a blast of high prcssure stcarn. Thc ntol tcn mincrai isorstnregrated lnto snlal I droplets which are attcnuatcd into viscousf i la.nrcnts as thcy are blown l long by tnc steanr jc i . - fhc

f i lanrcntssolid.ify as_ thcy cool, forming fibres which arc collcctctl on :rnroving belt as a blanket or batt of mattccl fifrr.. n bin<lcr ofrcsin may be sprayed on to the batt, ancl thc icsin .ur"J Uypassirrg the batt through a curing ovcn. Altcrnat ivcly, thc bnitnray be sprayed with oil and thcn broken trp into looic fibrc.


liinc Struc(urc and Appcarlncclr4ineral s. i l icate f ibres are gcneral ly snr oot h-su rfaccd and glass-likc in appearance, ancl are of alnrost roun,.l c.oss_s"ction.'l'cnsilc

Strcngtlr

I'Iigh.

Spccific Gmvi(y

2.8-2.9.

Iiftcct of Moislurc

Ncgligible.

fhcrnr:rl Propcrlics

Mineral silicatc fibres are-gcncrally resistant to tcnlpertturcs of,for example, 850-900"C. for prolonged perio<ls.'l'

lu'nttal conductivity. Low.

F I o nr rnab ility. Non-llamrnable.

Chcnrical Propcrlics

Mineral s i l icate f ibrcs arc crrcnr icai ly incrr, nntr wir l rcsist nrosto[ thc chenricals cncountcrcd in norrnal usc.. fhcy rcscnrblc glassin their react ion to most chcnt icals.

Iiftccl of Orgnnic Solvcn(s

N i l .

il

t-F t F F F F,-l''1-lt1 F, t F, t f''�'�I F t F t t l"'iI I A N D B O O K O F ' T E X T I L E F I D R E S

Iosccts

Complete ly r es is tant .

Micro-organisnts

Complete ly res is tant .

IUINEI{AL SILICNTE FI I }RES IN USE,

A4ineral s i l icate f ibres arc used largely as thermal and acoust icalinsulat ion mater ials, especial ly where resistance to elevated tem-peraturc is an inrportant factor, e.g. in boi ler and stcam-pipeinsulat ion, and thc sound-proof ing of bui ldings.

SILICA FIBRES

Fibrcs spun from si l icon dioxidc (si l ica), which nray or nray notcontain minor amounts of other mater ials.

si o,

INTRODUCTION

The element si l icon is the nrost abundant in the earth's crust.occurring in comb.ination with many other elements as silicates,and in the form of its oxide, silica.

Si l ica occurs as agate, amethyst, chalcedony, cr istobal i te, f l int ,jasper, onyx, opal, quartz, rock crystal , sarrd ancl t r idymite. I t istypically a hard, transparent, glassy mineral, with a very highmelting point. Quartz, for example, softens at about 1,500"C.,and melts at 1,710-1,755"C. I t is chemical ly extremely stable,resist ing the attack of almost al l common chemicals.

In 1838, a French scient ist , M. Caudin, discovercd that fusedquartz could be drawn out into f ine l i lamcnts, and thesc weresubsequently uscd as springs in torsion balances. Tlrey are st i l lused for this purpose today, providirrg spr ings t l rat have almostperfcct elast ic i ty, and do not undergo deter iorat ion from fat igueor corrosion.

In nrore recent t imes, quartz f i laments have assumed a newimportance as high-temperature-resisting fibres, and they are nowbeing produced in considerable quant i ty for appl icat ions whichrequire high{emperature-resistance and corrosion resistance.

t 7 8 t'l9

^ : N A ' r U I t A L P O L Y M E I T I I T O I ( I : S

. .The _outslanding. propert ies of s i l ica in thesc rcspccts hasstinrulated. the development of other routes to,iii"o fiUr"r. .f.ir"yi l rc now being produccd . indirect ly from grass nranrcnts wrr icrrare treated to remove const. i tuents othcr thin si l ica.

A modi l icdt ion of the lat ter_ technique "onri . i r - in spinning a:l::::.. 11."1""t containing. a hi gh pr.oporrion oi'hn.tv-airp.ri.,tslrca; ure organic mater ials arc then burned lwny to lcavc i rporous f i lament of s i l ica,.TYPES

OF SILICA FIBRE- - - . - - - - ' - - - - - - -

Si l ica f ibres nradc_ by the routes indicatct i : rbovc arc si ' r i rar i r rthat they are al l basicai ly si l ica, Uut t t rcy Aincr in ccrtaincharacter.istics which crerive- f.o- dl["."n"";i,, ii;;i; r.crhorrs ofproduction. The fibres are -best considered ."pnr,ii"iy, urcrc[orc,as dilTerent types of silica fibre:( l ) Quartz Fibrcs.(2) Si l ic l - f ronr-Class Fibrcs (Si l icn (G) l ; ibrcs).(3) Silica (Viscose proccss) Fibres (siiica lVf irlt r.rl.

NOMENCLATUI{E

Silica llbres are inorganic fibres, an<Jcategory- o.f. high-tcrtt perot u re fibres.described also as ceranic libres.

they comc w i th in tho1'hcy are conrmonly

(I) QUARTZ F]BRES

Fibres spun fror-n na t ural ly-occu rr ing si l ica in thc fornr oI qtr:rr lz.

PRODUCTION

Rrrv M:r(crinl

9r: l j : "1:^^l_l !os-t purc lornr of s i t ic l , which occurs narrrral lyrn nlasslve Lonn, c.g. as rock crystal , and as si l ic i r s:rn<. ' .

Spinniug

The lne l t i ng po in t o f quar tz i s . i n thc reg ion o f l ,Z l0 to I ,756"C. ,l:O.l!",t l,|"arion of-quarrz into fibrei t,as tr.",i

-,na,r" possiblc

Dy ule dcveloprncnt of tcchrr iques capablc of opcrat ing at suchhigh temperatures.

I ' I A N D B O O K O F T E X T I L E F I B R E S

Quartz fibrcs of 5-10p. dianreter are urade by softening quartz

rodi in arr oxy-hydrogin flanre, and drarving the rods out into

filaments of about 0.1 mm. diameter. These are then passed

through a series of oxy-hydrogen jets, the quartz being blown

forwaid by the jcts to form fine fibres which collect on a rotating

d rurn.Continuous filameuts may be nrade by softening quartz rods

in an oxy-hydrogen flame, arrd therr draw.ing out the fused quartz

into f i laments of dialneter 0'7pr and less.

STRUCTUI{E AND PROPERTIES

Fine Structurc and APPearancc

Smooth-surfaced, glassJike filanreuts of near-round cross-section'

Tcnsilc Strcngth

Quartz f ibres arc strong. Tensi lc strength is typical ly in thc regiotr

o f 650 kg . /mm! .

Elas(ic Rccovcry

Quartz is an alnrost pcrfect ly-elast ic nratcr ial , recovery frotn

defornrat ion being almost 100 per cent.

Spccif ic Grnvity

2.6.

[,llcct of Moislure

N i l .

Thcrmal Propcrlics

Soltenirrg Poirrl. 1,500'C.

M el r i n g Poi n t. 1,700-1,7 56' C.

EIJect ol lliglt TenrPeralure

Quartz fibres may be heated for prolongcd periods at tempera-

tirres up to I y'00-1,600"C. without undergoing deterioration'

F I at n nnbi l i t y. Non-f l ammable.

t 8 0

f i - , t ' - l - _ 1 ' - l ' I ' l ' l ' [ ' I I ' I ' ' l - l - - r

A : N A T I J R A L P o L Y I v I E R F I n R n . s

T lrerrtnl Cond uct ivi t y. Low.

CLcnricll Irropcrlics

tI citl.r

I-lig,hly resistant to all acids exccpt hydrofluoric acicl, cvcn a[tcrprolonged treatment at . normal t"'.p"r,ili,,o.'-itractcd byphosphoric acid at elevated ternperaturcsl

Alkalis

altcr prolongcrl I rcatrncntat 90'C. nrty catrsc sonrc

I- l ighly resistant to most alkal is, evcnlt norrnal temperatures. Cnust ic potashross o[ st reng I h.

G e ncral

I ' I ighly resistatr t to almost al l cornnron clrcr l icals.

QIJN IITZ I?IBIII]S IN U.SE

Gcrrcral Chnmclerislics

9.,1nr, , i r . 1 strong, alnrost pcrfect ly clast ic nnt l corrosion-rcsist ln trrbrc, which is capable of withsran<t i i r t i ; , . r ; ; ; . ; ; ; ; ; up ro sorncl9!9".C .This.conrbinat ion of propert ies givcs i t a nunrbcr ofrn)portant appl icat ions in the indusir i : r f n. f i .

-" " '

lind Uscs

Quartz f ibres arc wi<lelv, l l . " . l .n l I i l t rat ion rrratcr i l r ls, cspccial ly

llh::: I::i:,*e ro corrosive subsrances ^".r1", irei, rcnrpcrarurcts essential These fibrcs are also ur..f n. 'i"r,,i"iiorr

rrrnrcrials,serving at ,ren)peraturcs abovc rhose *1r".; ,.,r1;;;;;,i iiticatc librcsarc norrnarrv used. Exanrnles of appricatiot,; ; ; ; i ; ; rockcrs ln(lnrissi lcs, jet aircraft, nuclcar powei plants nn.f l ,Ji isr. inf furnaccs.

(2) SrLrcA-FROM_CLASS Fil]RES (SrLrcn (c) FtERlts)Fibres, obta.inccl

.by t!9 treatnrcnt of glass f ibres to rel l tovc con-stltuents other than si l ica.

IN'TI{ODUCTION-['hc

dcrnaud for h igrr-tcrnperat u r.c-rcsist ing f ibrous nratcri lrs rvnsslinrulatcd by the Jevelopment of go, tu"rfr in., l i ,r. l ' 1.t .ngin".t 8 l

F,r''l - - F. n F, F, l"'1,H A N D B O O K O F T E X T I L E F I B R E S

cluring World War II. The exhaust ducts of thesc engines,

op"rui ing at temperatures in the region of 700 to 800'C', required

inrulutio-n from the airframe and other structural parts of-.the

^i i .r"ft , anct the insulant had to be reasonably fuel-t ight ' l ight

in weigit an<I able to withstand the prolonged high frequency

vibration associated with jet engines.Silica was obviously a suitabG material for this purpose' a.nd

a new rorrte to silica hbre production was discovered to provide

tfr" nUi. in quantity and it reasonable price'-This consisted in

roinni,t* ctasi nUre and then leaching out all the constituents

oitr.. tt-tni the silica. Fibres produced in tltis way werc over

96 per ".nt pure si l ica, and they proved admirable for the purpose

ioi*t i . i t ih.y tu"t"- intended. Since the end of the war' they

huue develop"i into on" of the most important types of higt-

i;;;;";;ir;;:t;sisiine fibres, with a wicle range of industrial

applications.

FORMS AVAILABLE

Sil ica (G) f ibres are commonly avai lable in - the fornr

f ibre, bait ( fe10, cloth, tapc, slecving, braided rope,

tubular cloth, cord and Yarn.

NON,lENCLATURE

Silica fibres macle from glass fibres may be - described con-

i""l""tiv t. t,f, ca (G) librei to distinguish them from quartz and

f.om siiica fibres'pioduced by the viscose process (silica (V)

fi bres).

NolcThc infornrat ion wlt ich fol lows relates pr inrar i ly to 'Refrasi l"

pioau..a by Thc Chemical ancl hrsulat ing Co' Ltd' , U'K' Thjs'nrny

fr" taken as a typical example of a modern silica fibre nrade

by thc lcaching of glass f tbrc.

PRODUCTION

of brr lkscamless

Glass fibre

This is produced in thc usttal wiry, as describecl orr page 649'

1 8 2

A : N A T U R A L P o L Y I t T E R I T I D n E sSilica Fibrc

l .n:,:^o^1y..rr 'oT of,glass f ibre or tcxri le to si l ica f i trrc or texritc lsln tneory a straishtfonvard extraction proccss, ftrt irr prtct icctlrere are diff iculties which. must tr. ourrioni..; i . l ise arc 1a1 tossof strength, (b)-increased britt leness u"A i. j , f .rr i , ,-f ,rge in lcnethand diameter of f ibres after processing t lr. gfoss nir ie or texti lc.

A typical manufact.uring process fol lows thrcc stngcs:(a) Chopped glass fibrc is lcachecl with hydrochloric acid until

most of the non-si l ica nratcrial has bcen rcnrovccl.(b) The leached fibre is washecl and then fcltcd into bhnkcts or

batts.(c) The batts are dried and heat-treatecl, the t ibres bonding

togcthcr to increasc thc strengl.h of thc nratcrial.


Chemic:rl Slruc(urc

Si l ica . f i .bres produced by the leaching of gl tss f ibrc arc alrnostpure si l icon dioxide, commonly over 9g per ccnt. - fhc

conrposit ionof a typical modern si l ica (C) f ibre of ih is typ. ( , l tcfrasi l ' ) is lsIo l l ows :

sio"Fe'o'

Al,o, ITiO, JCaOMgo

Thc balance consists ofelemcnts,

98.7 per cen t0.1 per cent

0.4 per cent

0.3 per cent0.1 pcr ccnt

combined water and traccs of othcr

Finc Slruc(urc :rnd Appcnrancc

Smooth-surfaced l ibre of near-circular cross_sccl ion. Ir ibrcd ian re te rs range l ron r 0 .0 l .n t rn (5p ) to 0 .02 n t rn ( l 0p ) . I i i l l r cleng th i s abou i l 9 n r r r r (% in , .

Si l ica (G) f ibres are whi ie. Batt arrcl bulk f ibrc arc l ikc rawcotton in appearance; tcxt i lcs rescmble glass tcxt i lcs.

il r83


Fibre length of batt ( fel t ) and bulk f ibre nray be varied betwecn6 and 50 rnnt ( /a-2 in).

Vcry l ine l i lament batt is also manufactured with a f ibrcdianrctcr of Q.75p..

Tcnsilc Strcngth

Silica (G) fibre textiles have adequate strength for the nrajorityo[ appl icat ions. Minimum breaking strer)gth of a typical yarn,5950 nr /kg (3000 yd/ lb) is 0.454 kg ( l lb) ;3570 rn/kg (1800yd/lb) is 0.908 kg (2 lb).Elongation

Vcry low.

lilastic Recovcry

Si l ica (C) f ibres have a lmost per fect e last ic i ty .

Spcci l ic Grnvi ty

2 . 1 .

liltcct of Mois(ure

Si l ica is not affcctcd by moisture, the propert ies of thc l lbrcbeing unchanged when wet.

1[ hcrnr:rl Propcrlics

Sof tcrring point. 1,500" C.

M elring poitrt. 1,70O-1,7 56'C.

lilJect ot' 17 iglt TcrnpcraturcSi l ica (C) f ibrcs remain unchangcd after corrt inuouslonged exposure to tentperatures of 1,000"C., and willnruch higher temperatures for short per iods. Resistanceshock is high. Fibres may be heated to I ,000"C.quenched. in cold water without appreciable change.

F Iarnrn abi l i ty. Non-f lanrmable.

T lrcrttnl Conductivity' I ' l ' re

thcrnral insulat ion af lorded by si l ica (G) f ibreextrenrely high.

and p ro -withstand

to thernraland t hcn

l

. J[l r --l r - r ' I

184

lext i lcs is

i l " t 8 5

A : N A t u R A t _ p o t _ y M u n r t r r r t I sSpccilic II eat

7 'anp (C. )2605388 1 5

10951370I650

Chcnrical . propcrtics

tlci tl s

Silica (C) fibres are vervand phosphoric acicls.

tl lk o lis

B.T'.U.sl lb. l"F.0 .190.210.230.260.270.28

Culs.l t : .1"C.0 . l90.210.2Jo.260.270.28

stablc to acids, othcr t l ran l ryt l rof luor ic

Si l ica (C) f ibres arc stablc to nr i l t l a lkal is at lorv or high tcrrrpcra-turcs, bur srrong alkat is wi l l causc , ; ; ; ; i ; ; ; ; i icrrsi tc strcngt lrand rclated propert ies.

Gcttcrul

I{esistance to ntost conrlon chcrnicals is exccl lcrr t .

Insccls

Not attacked.

lVlicro-organislns

Not attackcd.

Dlcctricll ltropcr(ics

Si l ica (G) f ibres are extrenrely _ goocl high tcr lpcraturc clcclr icalinsulators, ancl are virrually'tri" ""rv'"i",,rir"ii._iiir" nrrterialsavailablc in texti le.fornr that wil l scrvc as cicctr ical insulants atlenlperalures up to 1,000"C-l 'hc

table belorv shows valucs for thc insulation rcsistuncc ofsilica (G) fibre cloth at various rc,irl...,rr*',rr",t"i"rurin"ct t y'l'he National physical Laboratory, U.K.

t E F t - - l"1 t t t t t l'"i |,',i r:I I A N D O O O K O F T E X T I L E F I B I T E S

I nsulatiott Rcsistance (olurrs I cnf)5 x 1 0 7 t o 5 x 1 0 85 x 1012 to 2x 10 r l2x 10e to 5 x 10 '2x 107 to 5 x 107

relate to plain weave, 0.45 nrr l (0.01 8 i rr)relate to 8-end sat in weave,0.90 mrn (0.036

Si l ica (C) f ibrcs of low boron content may be used in regions ofhigh neutron and ganrma f lux without appreciable radiat ionheat ing el lects. ' I 'he

fol lowing f igures wcre obtained by exposingsi l ica (G) f ibre mater ials to neutron bornbardment in the CLEEPreactor at U.K.A.E.R.E., Harwel l , England.

A4 ucrosco pic N uclcarAbsorptiotr Cross Section(ctrt2 per grarrr)

0 .01 60 .0160.019

I'etrtp. ("C.)20

200500900

l/o/e. Lorver figuresthick. Fl igher f iguresin) th ick .

Eltcct of Iladiation

lul at eial

I{efrasil tape T-RF-3Rcfrasil yarn Y-RW-445Relrasil fibre F-RF-75

These lorv values mean that the mater ials are completelysat isfactory for reactor use, espccial ly since the thermal propert iesrenrain substant ial ly una{Iected by neutron bombardnrent.

SILICA (C) FIBRES IN USE

Gcrrcral Chnractcr ist ics

Si l ica (C) f ibres combine l ight weight wit l r low thcrnral conduc-t iv i ty, f lexibi l i ty, high tcntperature rcsistance and high resistanccto thermal shock. In addit ion, thcy have the chernical resistanccthat is character ist ic of s i l ica, and cxcel leut l . r igh tcntperaturcelectr ical insulat ion propert ics.

Si l ica (C) f ibre batt has a br.r lk density in the region of 4lb./ f t r .(64 ki lo. /mr.) . I t can be conrpressed to a bulk density of about9 lb. / f t3. Datt consists of a close selt-bonded fel t of f ibres inter-locked in randont or ientat ion. As no bondirrg agent is used thercis no distort iou or loss of strength at high temperatures.

t 8 6

: N A T U R A L p O L y t \ . t E R F l t l R I l S

Silica (G) libre textiles havc. adequate strcngth for nrost applica-l ions, but where heavv abrasion i i f i t " fV- i" i " . r"r"ounr"." , f , " .g.in the rnachine braidins "{ .rl*, il''";;, ;,lilrcferablc totreat the goods with a f in_rshing agent that wil l incrcase thcirrcsistance ro abrasion. This ;e;it;' ,fr"' u..lif ,lg or orhcroperation to be carriecl out. successful ly, and thc f inish isrcnroved..quickly whcn the silica gooas a.e iiri tr.nt",f in ur..The.application anct removat of tri" "oati"! ir.r',lo .n..t nt orr;lrjll"

n""t thermal an<t elecrrical pdffi;-;i';c silica (G)

littd Uscs

Tlrc ind.us,tr ial appl icat ions opcn toand varied, but they fal l nrainly into

( l) I { igh tenrperaturc clcctr icr l(2) [ l igh tcnr l ;craIrrr .c t hcr lra l(3) Chcrnical cnginccr ing.

si l ica (C) I ibrcs arcthree groups :insulution.

insu la t io r r ,

rni lny

I Iigh 7'cnpcrature Elcctricol Itrstilutiorr

:lXilJ:l,ltf :l:^,r'^1,^:r.._:1,:lrs alcr.tapes are userr rbr a varicty o|,.i,of;i,',::,",.,,j,_,]l:.,:i::ili:,,"u,a,!tiii J.j.i;";;;;:,ii;;:';l,i:lfi.: lil:. l' ::ll l g" :l:"t :l I :l ;' ;; t; ;;';; i? ;'ili'fi I :'::';: lii i;;j:'J;::l*:ll:?.'."',.1:1,::,'i;;i,;i' ;;;;;Jiiilii ;;':,::5::illi;for thernrocouples, high fr.qu.u.y f.rroti , ,g .oif i .II igh Tempcrnture Therna! Insulatiort

il;,1,li','_t';;l:lf ,l,

l:,*,-..,.,.,1:rr,y r., therrnal insr la tor, sit icr ( c )lloI i:":;.1"',i,1:,1:1,:,_:i:,{,t';;; ;il;il;:[]:lli',drliIi, Jf,]ll, h. u':.1 in. tne followi,,; 1;,;;;;; 6i'il;,;"ilii'?,lill":l'i:,lill i l t r e ) , ( b ) s i l i c a f i b r e c l o t l r c o v c r c r l h h r r t z a r c / ^ r ^ r r , ^ . . - r r - _ . . . rfliTl; l?, ";l.,ll,,ll;:,:i: t.:,;;;;*i ii,i;k";;, iii"lil'll,i,,,,lii 'i!:l,l': ::1,,:f 9.",'l*_:l.ii; :r;i i;;''.;;i'il;ir,, iiii'i,ii'iiJillliill" lI," y,, :.1 .l:. r, u,ic, t Jl i,ii ; i;il.J .,ii l1;, J,ii,, fiL i: j,lililf . liij;. 0 ;?,:i. :i::,:, -:I t.l" r,l .ii, r p "i ii,l' ",i iJ,,ii,.,ili lii,"J:i;j:lfi,

and also to proicct- per,"li,iii"r,,'i,igii'ili,p::lli'l:p r oce sse s.Clrctnical Engineeringln high ternperature chentical engineering operations ltcl iasi l is

ii ill* l ii qs: n':;{r,$ ri rii,f, lir*l[,'# fu iil;i I187

I I A N D ! O O K O T T E X I ' I L E F I B R E S

curtains in conveyor-fed annealing and nornlal ising lurrraces andalso draped over large castings to control the rate of cooling. lncontinuous steel casting processes gaskets precision cut f ioruthick Refrasil cloth are used in special valves control l ing the f lorvof nrolten metal. Refrasil Ropes are used in gaskets for furnaccdoor seals. Many other applications involving newer fornrs ofRefrasil materials are continually being found in high temperaturechenrical engineering and engiueering processes.

In atomic cnergy applications, the low boron content of silica(G) fibres is advantageous jn that there is no heating effect whcnthe si l ica is irradiated with neutrons.

(3) SILICA (VISCOSE PROCESS) FIBRES; SILICA (V) FIBRES

Fibres produced by dispersing si l ica or der. ivat ivcs in viscoscsolut ion, spinning by the usual v iscose techniques, aud thenremoving the conrbust iblc mater ials to leave f ibrcs consist ingsubstant ial ly of s i l ica.

INTRODUCTION

The product ion of f ibres front a high-melt ing ntater ial such assilica presents considerable technical difilculties. Filarnents may bemelt-spun by a direct process, as in the case of quartz, but thisis not readily adapted to thc production of textile grade filamentson a large scale.

Fi laments may, however, be produced by indirect methods,as in the production of silica (G) fibres, in which the fibre isproduced by spinning a lower-melt i rrg mater ial which is sub-scqucnt ly couverted to the high-nrel t ing nrater ial ,

'l-his indirect rnethod of production nray be taken a stage

further, as in the production of silica (V) Iibres. The silica, intliis casc, is dispersed in a solution of viscose, which is spun intorayon in the usual way. The cellulosic material of the viscosernry thcn bc burnt lway ut any st i rgc o[ proccssing, to lc irvc afibrc lormed fronr tlte silica residuc.

t

r 8 8

t

A : N A T U R A L P o L Y I v I E R F I I } I I E s

. Thc technique of producing f ibrcs fronr inorganic runtcri:r ls i 'this way has been undcr investigation for a cionsi<tcrable t inre.Early fornrs of inorganic fibre weie weak, howcvc.r, antl thc higlrloadings of, inorganic material precru<red trrc nianutacture ofanything other than coarse filaments, e.g. of 5011, dianreter.M9{ern research, notably by,Avtex Fitr.r, j i i . . , has--rnatlepossible thc production of very line firarnents of silica and otrrerhigh-melt ing. mater. ials by the viscosc tcchniqrc. i i tre basis of

:,]:_fl:"::. rs. ro disperse the inorganic materials in a very linclornl ln the vrscose solution.

.. Many ir iorganic substances are soluble in alkali , ancl wil ldissolve in the viscose solution. They are suUsclucntty regcnc-rated as the viscose is coagulatc<l in the coagulai ing batlr,-pro_viding a fine dispersion oflhe inorganr" *otJiioi in urc viscosei lrantent-

Si l ica has been madc into f i lar i rcnts success[ul ly by t l t is v iscosctcchrr iquc, a,d rayon f ibrcs arrtr f^br ics corrtnir i i 'g sir icn rrro,cor nr ixed with carbon and other substanccs are oir i l rc nrarkct( 'Avceranr ') .

NOMENCL TURE

Sil ict f ibres rnade by thc viscoscconveniently as ,ri/ica (V) libres toand from silica fibres procluced byrrique (silica (G) fibrcs).

Nolc'l-he

information which follows relates orirnarilv to .Avccrant,produced byAvtex Fibers Inc., U.S.A. This nray tr . i . f , t l , as a typicalexanrple of a modern si l ica f ibre rnade by t i re viscosc tcchniquc.PRODUCTION

Spinni r rgProduct ion of s i l ica (V) f ibrcs by Avtex Continuous Ccrrrrr icl j rbcr Proccss rnakes trsc of thc convcnt ional v iscosc proccss(scc pirge l l ) . Sodium si l icate is dissolvc<l in t l rc viscosc solut ionprio.r to.spinning, ancl this is convertecl to hyJrutcJ si l ic ic acidduring the coagulat ion of the f ibrc in thc aci i coagirht i rrg bat l i

The. tcchnique uscd is, i t r t l r is rcslrcct, di [ Icrcrr t f iorrr Ure lorrg-establ ished technique oI incorporai ing part ic lcs of pigrncnt or

1 8 9

techniquc nray bc dcscribcddistinguish t lrcnr froru q uartzthe glass f ibrc Ieaclt ing tcch-

T

tE t t t t t t t t t t t t t tIl

' . I A N D B O O K O F T E X T I L E F I D R E S

clelustrant in spinning dopes. In the latter case, the resulting fibrecontains essent ial ly the same part ic le. s ize inorganic mater ial asrvas suppl ied in the spinning dope. ln the Avtex process,

inorganic mater ial is dissolved in the spinning dope, and is thuspresent in a nrolecularly dispersed form. As the cellulose hasbeen regenerated in the acid coagulating bath at the sanre timeas the inorganic material is precip.itated, the resulting hybridf ibre has few, i f any, domains of ei ther cel lulose or si l ica, but isessentially a continuum of both these materials.

'Ircatnrcnt of Fibrc

Fibres produced as above may be furtlrer processed at any sub-sequent stage to produce a variety of protlucts, including a silicafibre.

Pyrolysis of the rayon-si l ica mater ial under reducing condi-tions witl produce a carbon-silica fibre. If this carbon-silica libreis oxidized, thc carbon may be burncd of l and a si l ica f i lamentIormcd. Alternat ivcly, pyrolysis of the rayon-si l ica f ibrc may bccarried out under oxidizing conditions, resulting in the directformation of a silica fibre, without goirrg through the carbon-si l ica f ibre stage.

Thc carbon-si l ica f ibres produccd in this way arc unique inthat both the carbon and the silica are present as fibrous struc-tures. This may be shown by the fact that oxidation of thecarbon-silica fibre results in a fibrous silica, while chenricalextract ion of the si l ica from the carbon-si l ica composit ion resultsin a f ibrous carbon product.

Since the carbon and si l ica are indist inguishable as to structure,even using high magnification electron photomicrography, thetendency for these materials to react to form silicon carbide isenhancecl. Treatment of the carbon-silica fibres in an inertatmosphere produces cont inuous si l icon carbide f i laments.

Two products, based on rayorr-si l ica and pyrolysed rayon-si l icaarc produccd comnrcrcial ly by this proccss, uncler the tmde nanrcs'Avcerarn'- l {S (rayon-si l ica) and'Avceram'{S (carbon-si l ica).

STITUCTURE AND PROPERTIES

( 'Avccranr ' -RS and'Avccram'{S) .

F ine S(ructurc l t t t l Appcarnncc'Avceronr ' -RS yarn is a conrposi t ion of rcgcneratcd cel lu lose an<l

190

A : N A T U R A L P O L Y N , I E R F I B I T E S

silica. The composition may be varicd ovcr a widca si l ica content of about 60 per ccnt by weight; i l leproduct contains approximately 35 per cent si l ic i andregenerated cellulose.

rangc Up tocorrtnrcrcial65 pcr cent

unnrod. i f icd rryon;

and 65 pcr ccrrt

'Avccrnnt'-CS

5 3 ((, .0)il ,200 ( 160,000)

^.The f ibres are superf ic ial ly ident ical withl r l a n r e n t i s 1 . 3 d t e x ( 1 . 1 5 d e n ) .. . ' .Avcerant ' {S contains 35 per cent carbon

s l I l ca .

- The f ibres are sinr i lar in appcarance to typical carbonf i lament is 0.69 dtex (0.62 clenj.

Tensile S(rcngth

rena.c i ty -cN/ tex(g /den) 'n i | ' i " ( [ .a f t' Icnsile Strengrh kg/cnrz ( lb/ inz),3500 (SO,OOO)

srl-rcn (u FrrllrF.s rN usrlRayon-si l ica yarns ntay bc wovcn, kni tred, fc l tcd, choppcd intostaple, or madc into fc l ts or papcrs. Control lcd pyrolysis topr*r: : the dcsired typc of s i l ic i , s i l i "a-"urbon-oi . i t i .on cnrbidcn ra rena ts may be ca r r ied ou t a t any s tagc .

Thc. fabrics produccd in this way uscJ prirnarily as rcinforce-nrent in the manufacture of high i . rnp.rntur" rcsin systenrs foruse in rocket and missile technology, e.g. rc_entry systcnl hcutshiclds and rocket nozzlcs.

l 9 r

I}: SYNTIIETIC FIBRES

I, POLYAMIDE FII ]RES

2. POLYESTE,R FIBRES

3. POLYVINYL DEI{IVATIVES

4. POLYOLEFIN FIBRES

5. POLYURET}IANE FIBRES

6. MISCELLANEOUS SYNTI-IETIC FIBRES

Introduct ion

The nranufacture of synthet ic f ibres is a wondcrful cxlmplc o[ theway in which industrial chemistry is contributing to modem life.We now accept synthetic libres such as nylon and 'Terylene','Acrilan' ancl 'Courtelle' as everyday nraterials, using thcm ascasual ly as we use the rvool and cotton, f lax and si lk that haveprovided man's fabrics for thousands of years.

Yct until tlre 1930s, synthetic libres existed only as a few experi-mental lilarnents that showed little sign of serving any usefulpurpose in the textile trade. Who would have dreamed that intwenty years or so the production of synthetic fibres would havebecome one of the world 's great industr ies?

During the early years of the present century chemists becameinterested in the unusual ntaterials we now know as plastics. Intime, it became realized that the strange properties of plasticswere a consequence of their molecular structure - their moleculesrvere long and threadJikc, nrade up of atonts strung together likcnr irr iature str ings of beads.

These materials rvith thread-like molecules became known aspolynrcrs, and during lhe I920s and I930s great progress wasrnade in the study and understanding of polymers of differenttypes. It was found that rubbers and libres were polymcrs, thcirunique propert ies deriv ing from the part icular shape of longmoleculc thcy possessed. Fibres, for example, were polymers inwhich thc long rnolecules could pack together alongside oneanothcr l ike st . icks i rr a bundle of faggots.

t92

l , ; , 1 r I r t

193

D : S Y N T I I E T I C F I D I T E S

In thc years after World, War.. I , . chcnrists carr icd out n grcatdr:al of rcsearch on nerhorls " i r i , iH,rg'r ir ' . t l i , l i , 'un.t groups of::?:: l l1 such a way as to cr-care lo,lg;,; i ; ; ; ; ; . Ma.y synttrcricporyrners werc made. sonrc of rtr.n, t '" i , ,g-jrtn.i i .r, ,ot l , . . . rubbcrs.. l l i"r," i rhese potymers woutct ct issolvi i ;r";; i l , , , . , an<t ir wasrra.turar for people to try.extruding tt" p.1v,,,""r 'r" lrrt ions t lrrougrrsprnncrcr holes ro f ind out wherh]er nl;; ; ; ; i ; ' ; i . t bc rrradc inthc same wty as ravolr.

^" 1'-,.t-":9. ogo o. -i913, cennan chcmists werc producing ancxpcnrnental fibre frorn polyvinyl chlorid;-in'i;;s way. But thc

lP::^:1.- "r tirtle inr.ercsr ir-n'pot"ntioi1"*rii",.ho*. tn te2|,nDrcs were spun in GcrnranyAonr n ."p"1y"i". 'ol vinyl chlorir lcand vinyl-acerare, anct in rg:c " n;;;-;; ; 'b"i i ,g n,u,t" "on,-rncrcially from chlorinar*a noryuilri'.il;d;. fiil *r. rhe fibrcPc cc, which many claim_ as the f irst synthctic tcxtire f ibrc._

p" c". was onry of tirnjrc<I.;;1,,;';; ;il;il ii,l., nn.r it *a,ncvcr of grcat cornnrcrcinl inrportancc. .fhc rcai-bcgirrnin[ ollhc synthetic fibro industry was to stem r.o,r., il. wurt of wailacc

|l_^C1lo,Jr*. on polyesrcrs and polyanridcs, whictr lcd to rhclrDrc wc know as i ly lorr .

^.Today,^polymer circrnistry is onc of thc nrost f l r i t fu l branchcsot scient i f ic research. and,p u n i n ro r"i iii;ilf :; ;lill;?:H:i.i:,'#xT ;[: n o* r,.i iig


I, POLYAMIDI' TII}RES

INTRODUCTION

Polyarnides are polymers which contain recurr ing amide groupsas integral parts of the rnain polymer chains. Naturally-occurringpolyamides include the protein fibres, e.g. silk and wool. Syntheticpolyarnide fibrcs form one of the most important of all classesof textile libre, which we know today as nylon (see Nomenclature,page'207).

Synthet ic polyarnides are made by a condensat ion react iontaking place betwcen small moleculcs, in which the linkage ofthe nrolecules occurs through the formation of amide groups.The reactant molecules are selected to yield linear molecules ofpolyamide a{ter react ion has taken place, and the l inearpolyanridcs from which ntodcru nylon fibres are spun arc typicrllyof trvo structural typcs, which may be represented as follows:

(l) H"NRNH(COR'�CONHRNH),,COR'�COOH(2) H?NRCO(NI-IRCO),,NHRCOOH

In each case R and R'represent chains of atoms separat ing thcfunct ional groups, and 'n ' represents the nutnber of recurr inguuits in the polymer molecule, i .e. the degree of polymerizat ion.

Synthet ic l inear polyarnides of these two types are producedby one or other of the two fol low.ing routes:

(a) The type of polymer shown in ( l ) above is produced by thcinteract ion of a diamine and a dibasic acid, e.g. hexatret l ty lencd ian r ine and ac l i n i c ac id :

Nrt, {cH.)u NH. + Hooc (cn.)o coon

HEXAMETHYLEI IE

- - co NH (H. )o HH co (cu . )n co NH (cH. )o Nn co (cu . )o co - - -

N Y L O N 6 : 6

P O L Y H E X A M E T H Y L E N E A D I P A M I D E

t94

D I A M I N E A D I P I C A C I D

II+

F F F F F F F F F F, F N F F1 N NF, NN : S Y N T T I E T I C F I B R E S

,(b) Th.c type of porymcr shown in. (2) abovc is proauced by trrcsglf-condensa t ion of an ar' ino lcid, or a <terl iv; i ivc srcrr as atacl .anr:

cx. (cu.)., co N r-r

> --r.rH (cx.). co HH (cH.)" co r.+r (cx"). ___

CAPROLACTAM NYLON 6

_ libl::, have been. spun experimentally from ilrousands ofLo,Ll.tu".^ produce(l by one or other of thcsc condcnsationrcac'ons. But onlv a very few havc attainc<l real cornrnercial' inrportance in rhe-rnode.i.rexti le inclustrt.- i i ;" ' ; ; them, whichlt:,l"oy.now as nylon (or, nlo." p...ir.iy,

-nyion 6.C _ s..l \omenclature, page 207) was thc f irst conrnrcrcinl ly succcssfulsynthctic lcxti lc f i brc.

Nylon 6.6

The story of nylon's discovcry is a ro.rarrcc oI nrodcrn scient i f icrcsearch. It is the rcsearch of fiction conrc to iiic; ttrc "t,nnccdiscovery that led to a world_wid" inJurt.V.- '- "'-

^ In 1927, the managemcnt of one of amliica,s largest chcrnicalfirnrs, p. I. du pont de Nemours & Co., decideJ ifroi tn" outlooko[ their industry was becoming too r"stii"toL-M'Jr" on.r nror",thcy were depending on."."n."-h to k;"p i i ; ; ;uir ' [ 'aot" in rhcirprocesses and in their developmcut of n"* pro.lr'rcts. But to alarge extent it was .directed' ,.r.0..I, ].;;;;.;ir-;; was retatcdto. the products already being manufacturcA, anJ-io cstabl ishcdscientific fiel<ts.

Backed by this research,. du pont was f lour ishing; but in spi teof. this, insuf l ic ient was bcing donc to broadcn thc scope o[ theirtdustry during the years ah-ead. rt *o. a."iJ"al ihcretore, thatrcscarch should begin along l ines which did noin"ccssari ty t"arrny. direct relation to the bread-and_bu tter ,lii"lti* of thc firnri lscl f . The research chemists would bc gi" ." " ' f r . . hand tocxp,lore at will in any new scicntilic territo;; to-*fri.n ilrcir fnncytook.. them. They would not be expectcA ti .o"trifri,tc anythingo[ direct conrmercial value to the tirm; no. *oiita thcy havclo convincc lhe managentent of any irs"fut prrposc in thcresearch they chose. I t was to be reiearch for ' reJearcrr 's s:rkc.

195

T I A N D D O O K O F T E X T I L E F I B R E S

carr ied out in the convict ion that i f anything was discovered, i twould be something ent irely new. In 1928, the work began.Responsibi l i ty for lcading the team of chenrists fel l to Wal lace H.Carothers, a comparat ivcly young and l i t t le-known organicchemist who had served as instructor lor four years at lllinoisand Flarvard Universi t ies.

Carothers, during the next few years, was to lead his team witha br i l l iance that had rarely been surpassed in scient i f ic research.Had he lived, Carothers would lrave become one of the greatscient ists of our t i rne. But he died at the age of forty-one, beforethc rcsults of his work wcre to comc to frui t ion.

Polytncr Ilescarclt

Carothers and his tcam, irr 1928, chose for their research thcstudy of the long chain molecules which give us our rubbers,plastics and fibres. At that time the chemistry of polymers wasl i t t le understood, and much work had to be done before arradequate background could be built up in the new scientilic lield.Much of our present understanding of the behaviour of longchain moleculcs is a result of the work carried out by Carothersand his col leagues.

The llrst stage of the research included a study of the tech-niques by which short molecules could be linked together into longpolymer rnolecules. Carothers concentrated his attention uponthe production of polymers by condensation reactions, rathcrthan by addition reactions involving unsaturated monomers (sccpage xxiv). And in the initial experiments, he made use of thcesterification reaction between alcohol and acid groups to providcthe link that joined small molecules together.

In an esterification reaction taking place between two mono-functional substances, e.g. methyl alcohol and acetic acid, thctwo mater ials l ink to form an ester, and water is el iminated:

CLI"O[{ -t- CHTCOOFI+CH"COOCFI, -r- I-I,O

Carothers and his col leagucs carr ied out this react ion betwcerrdi funct ional substances, i .e. glycols, containing two hydroxylgroups, and dibasic acids, containing two carboxyl groups. Thcyselected re&ctants which would not readily forn.r ring molecules,in the ant ic ipat ion that the ester i l icat ion process would l ink t l rc

196

[ l r I , I r I t I ' I ' - I

B : s Y N , n l E T t C F I l t n E sglycol and dibasic acid molcculcs al tcrnatcly cnd-to_crr<l toproduce a long polynrcr nrolccule.

HO-R-OH + HOOC_R,_COOr{_>_o_R_ooc_R'_coo_R_ooc_tt,_.coo_

- l 'hc estcr i f icat ion took placc as cxpccted, and polycstcrs wcrcror.red' Initia'v, these rrrirt t'or."u r,ii -,u'.i!iri. '.'.,1"r,

ing into rrrc;lili :ri'XT,[,t;?3t;fi ,* :' p"'i "i" ni u i t-. !i' " i o *- r,".",''. u' o i.or,r*i,*aiii,iJlirrii,ll'",ii"Tif JJj;il,,ll,rTl".l,',i.I-;il j,ii jnanre superpolyesters. Tlwrl"n.sJriiini;';;"iifJ,:1"."""i:U,||v.cIcar,v.iscousriouiJs.,. P"jn.q this. carrv p.rio j,, carotli;.:

-J;' ilr";;iica gucs st u<r ictlthe rctarionships bcrwccn tt," p.op"ri i"s'; f ' ;"-,; ; ." anrJ rhcirrrrotecurar srrucrures. rnis ..rJnrili';il ;;#;tuiJrrar phasc olthc rcscarclr incrcasccl tr,ur vi"iJ.J'riiil ;;,;j[ii,,li}.T;rji'.}:l]',,i:.1:]',,'., scic.cc,

^. {n Anril 1e.39, o n un us11t "#"'.i;;;;;' ";'ffi l.por y..t",* *n.observed,.which._was ro prove of i ;",; ; ; ; i , , i iolnn.". lr ,un,nrscovered that jf the nroltcn polyest". *^.-t",,",i.,f with a gllrssrod, and the rorl was then <trawn iway, ,iri""f'r"*r.l,Iratcrial stuckP lltc lod' forming a Iine srrand ri,'tii,e it"'i.Jlncr thc nrorrc'|l1r:. lr :991 as rhe strand. t.rt trc'rrit'"i..ir," il,,nr.t thc cor<tnrr and solidified to fornr " t""J.o"ti"r""."rii i,i.nl"nr'rt. .I.hiswas quitc f lexible, and strong enough to be wound o, to a bobbin.D rawittg

Hcre, then was sonrethinq.or l j b; io; ; ; ; j ; ; , , ; , f ; . , , "*

_ a nrorrerr synlhcr ic uolyr ler r l rrrnrane n ts. J ;l;;";;';;;l"i'l"l:,;:iX?rin g thc I ong con rirr uous

,"ilH' ?i #ffJ "li Lll {i };!:1, :';: i...,':. ;l' j,t,,#, j ll. : Jl;tunti l^t}ey were scvcral t irncs thcir original lcngth. Whcn strclcl lc(lthc f i tarncnts s^owcd ,o tc.(tc..cy j" ; ." i i ; ; ;";" ' ' r irctr

origirrallcngth in r l re way rhar s t rc rchc j . , "bL; ; ' ; ; ; . : t . t , .y * i ,up lycxlcnded unti l a point was . rca.chcd _ ai- *f i i"f ,

-f , , . , f ,"r cxtcnsiontv:ts. rcsistcd, nnd thcy rcrnairrcd . in thcir ";; ' . | . ; , j , .

. . ._M.or.gu"r, rtre phyiicat charncte;isi; ; , f ir ," ' i f i lJ".,",. , ts rnr(rcr_tvcnt a dranraric chanrc afrer being ""1;;r^;;. ' ; ; , ' r1,.

, , , , . trnrunstatc, thcy werc duil an,r opoqr., with I i t trc resisrarrcc to rcusirc197

I _ F F F F F F F F

I I A N D B O O K O F T E X ' I L E F I D R E S

stress; in thc drawn state, the f i laments became transparent and

lustrous, and displayed great ly increased tcnacity, toughness and

clast ic i ty.Thcse two phenomena, i.e. the fornration of filaments from

nrolten polymer, aud the cold-drawing of the f i lament. to changeits propert ies, had rcsulted from the product ion of l inear polyester

molecules of great length. Condensation between the glycol andthe dibasic acid had resulted in polymers that were essentiallyl inear; there were no side branches or large pendant grot lps toprevent the molecules packing close alongside each other, andthe long molecules were able to form regions of crystallinity inwhich the forces of attraction between them could developeflectively. Also, the length of the polyester rnolecules was suchas to link the crystalline regions together into the structure thatis typical of a fibre (see page xi).

X-ray difiraction studies of undrawn superpolyester filamentsshowed that the long molecules were indeed packing togetherinto crystalline regions. But in the undrawn fibre, these crystallineregions were not in alignment witlr each other, or with the longaxis of the filament. They were in a state of random orientation'

lVhen the filaments were cold-drawn, however, the X-raydiffraction patterns showed that the crystalline regions wercpul led into al ignment unt i l they were or iented paral lel to thefibre axis. At the same time, drawing brought about an increaseddegree of alignment of the molecules in the amorphous regionso[ the filament. This permitted more of the molecules to packtogcthcr into crystal l ine regions, so that the degree of crystal l in i tywas i ncreascd.

Supcrpolyanides

The physical properties of some of these early cold-drawnpolyester filaments showed certain advantages over establishedman-made f i laments, such as viscose rayon, notably in tenacityand elastic properties. And jt became evident that superpolyestersproduced by condensing glycols and dibasic acids might providea route to the product ion of t rue synthet ic f ibres of real com-mcrcial value. Carothers and his team began a systematicinvest igat ion of superpolyesters with the ainr of producing sucha fibre.

At an carly stage, i t bccarrte apparcnt that thc st lpcrpol ycstcrsthcn avai lable had def ic ierrcies which precluded thcir being of

t 9 8

B : S Y N T I . I E T I C F I N R E S

value as comnrercial tcxtile. fib^rcs. In particular, thc rncltingpoints. were too low, ancl rhe nb.". ;;il--;;i withstrn<l rhcconditions which woulcl be encounterea ln rrornraf tcxtile usc.It was decided, t lrcrefore, that work . lrouiJ U.'"oncentratcd onlh: :l"dl of superpolyami<tes, which ;;t.t ;; cxpccrcd roprovide f i larnents with propcrt ies more satisfactoif to tcxti tc use.^ Initially, polyamides were produced uv

^r"ri"i".r"nsation o[9-aminononanoic acid. polynrers were obiaincd which nrcltecl atabout 195'C., and fibres spun.from tlri. ;;it;;;*;rc comparablein strength and flexibility with those "f ""iri.i

-.itk. Thi. *r,a promising start.

A wide range -of superpolyamicles was then maclc, using both. routes, i.e. the self-condensation of anrino-aciJs anJ tuctanrs, an.lthe condensation of diamines *it f , Jifosi" ' . i i i . . nt thc sarnctirne, the method of spinning ntam"nts iroi tii"

-nrof t.n polynrcrscame under intensive development. Instea<t of .piiining hfri., Uytouching thc molten nolymtr and pull int ;rr,^r";, strnnd, thechcmists. began extrui ing

. thc . moltcn polymcrs through f incorillces in spinncrets. In principlc, tfri, t.in,iiq,,""rcsc nr blc<l lhntused in spinning viscosc rnyon, but it invorvci ilrc cxtrusion ofi^T.1,1" Ti." held at high ternp"rutu." inrt;;;i" sotution ofpolymer at normal temDerature as in the case of rayon...This .technique of mclt spinni,r j ; ; ;r; ; ; j ' ; ,ry practicatdifliculties. The moltcn polymer i.,i t" fr"- fl"i,i nt o f'ligf.rtemperature without deconrposing during thc .p;"ui"g operatlon.Pumps, filters spinnerets ancl other .quirim"r,t li"J t" rr" dcsigne<.|

:^lp:T,,_" at thcse,high remperaturcs; thc f irst spinnerct uscrt inmcrr splnnlng morten noryanridcs was a' clectricai ly hcatcJhypodcrmic needle-

Following an intensive research campaign during thc carly1930s, a.superpolyami<Je was chosen f", 'fi;rrlr.;

;;;clopmcnt nsa potential texrile fibre. This was.polyh.-;;;;iily[;; arlipanridc,made by conclensation of hexanrethylei. Oianlin" an,i adipic acid.' Ihe potymer was of suitabl" rn"tt ing poini ' i"rr"r i ' iso"c.l , ""athe f ibres spun from it had properti .r ' ,n"i "r*[- i t attractivc as1..1.*t j l . f ibre. Equally inrporrarit , this polynrcr ol icrcd rhe rnosti l l tractive proposit ion frorn lhe point of " i"* J i"* nratcrinlsand tnanufacturing costs.

Once this dccision had been nrarlc, a ful l_scale dcvelolrnrcntcanrpaign was put in hlncl, with t l ic "fr i ." i-" i iroducing rpolyarnide fibre on a conrmercial rr.,i.. iii. -i..i'

Jn, ,o prou"

t99

[ I A N D r | O O K O F T E X l ' I L E F I B R E S

one of great conplexi ty. Thcre rvas no brckground o[. industr ialexpcrience on which the chemists and technologists could draw.Tlre process of producing polyamides was new. The techniqtre o[spinning a molten polyn-rer at high tempcrature had never becnattenrpted before.

Processes had to be devised for the manttfacture of the twomain raw mater ials, hexamethyleue diamine and adipic acid. Thcbasic source, originally, was phenol, and adequate supplies of thishad to be ensured.

Altogether, some eight years of high prcssure work by chernists,physicists, engineers and tcxt i le technologists were re<luired beforcproduct ion of the new f ibre could begin. ln Apri l 1937, the l i rstpair of stockings was made from polyamide fibre produced inthe experinlental plant. The process for making the l ibre was thcncstabl ished on a pi lot plant scale, and on 27 October 1938 thenews of this f i rst synthet ic text i le f ibre was announced to thcworld. I t was to be cal led 'nylon' , a name that had been coincdas a generic term for synthetic polyanride fibres.

Corttnterci ul P lod uct iot t

I ly t l re end of 1939, thc f i rst factory for commercial product ionof nylon was in operat ion at Seaford, Delaware. And by May1940, nylon stockings werc being sold to the American public.The end of 1941 saw nylon in product ion at Seaforcl to the extentof 3.6 mi l l ion ki lograms per year. [Jut this was insuff ic iert t tomect the dcnrand, and a second factory was opened at Mart ins-vi l le, Virginia. Front these two factor ies, nearly I 1.3 mi l l ionki lograurs of nylon per annum rvere turned out by 1942.

In Bri tain, thc f i rst nylon spinning factory was in operat ion byJanuary 194t, and the second by Decenrber !942. Canada, also,was in production. Dur.ing the war, all the yarn produced by thesefactories was uscd for essential war purposes. lvlost important ofalI rvas the manufacture of parachutes, which needed strong, lightand elast ic f ibre - a job for which nylon was adnrirably sui ted.

Aftcr the war, nylon product ion underwent an enormousexpansion. The new f ibre was soon being nranufactured in mrnycountr ies, and in nratry forms; mult i f i lament yarns, monofi la-rncnt, high tcnacity yarns i rnd staple. I t was accepted enthusiast i -cal ly by the gcncral publ ic, and has now comc i t t to use in almoslcvery branch of the tcxt i lc industry.

n , l- l ' I \r

[ "

t [ ' I , -J - I - I r I ' . - l . - l - ' l

I

B : S Y N T I I E T I C F I I } R E S

Nylon 6

Dur ing h is ear ly rcsearches in to thc producl ion o[ polyanr idcs,9ll:,h"ir- made .a !o!yT9i by the s;rf-c;;;"nruiion o[ capro-l:rctanr. He describe d. in .1932, ihe , ibr"s th"t;;ul, l be spun frornthis polymer, ana

' oolycapi";;r i ; ;

-; ; ' """

' ", rhc nranypolyamidcs consiclerccl for possible A"u.tofnrcIif"s a cornnrcrcialtcxti lc f ibre. Followins ttre decision r, ; ; ; ; ; ; i ;" on rtrc pro-

*:l':l of a polyhexinrethylenc ^dip;,,;i,i;;;;;, rrowcvcr, rhcpolymer madc from canrolaclanr wni no long"i a candidatc forinrnrcrt iatc developmeni by du pont.

lll .L,urope, consiclerabl^c rcsearch hacl bccn carricd out orrpolyanrides during the 1930s., notably fry tfr.-C"r"",,r firrn of I.C.F:rrbcninrtusrrie. tn I 937,. Iibr., ;;;. -6";;;

Jpi,n'i*p.rinl"ntntryfronr polycaproamicle, but i t was not unti l 1939 that thcsc l ibrcswcre being produced on a con)nrcrciurty p.*tr"oui" tasis.- During World War ' , . polycapioa1,, i l ;-; ; ; ; ; wcrc ,r i lnr-frctu.cd in Gcrnrany, nna'.,r l ,r

'r ,r,r.r^;"";;; . . 'cr lo' I . , ,Chcnrically, thcse nyion 6 I ibres fr"" ' f l", , ierl" i" ir,r", pne" zOzlrvcrc similar ro rhe nvlon 6.6 nbrcs p;;;; ; i ' ; ; ' . ,u ponr, t lrcsl ight dif lcrences in nrolccular structure lscc pngc 203) bcingrcflected in sonre dillcrcnccs ;" ri.," irirvri*i jfficrtics of thcfibrcs.

ln cermany, as in the u.S.A.. and Britairr, nyron f ibrcs rvcrcusccl almost e-ntirely for essentlat war purposes, notably in thcproduction of parachute .fabric.. Altcr ' thc war,"many oI thc' l)crlon L' factories wcrc disnra-ntlcd, 'Ui,t 'p.",1,," i i"" o[ t^c l ibrcbcgan rgain irr Gcnnany irr 1948. .

Polyanridcs I'odayNylon 6.6 and Nylon 6Sincc._lhe end of Worlcl War I l , nylon 6 anct nylon 6.6 havec.stablished rhemselves on th".wo.lJ'r"^rf,"t lJ t*l of the nrosrInrportant of al l synthet ic text i lc. f ibrcs. proJ,r . i io"

-of both typcstncreased at an irnpressive ra.te in tl,. i;;,;;li;i;"pir,**, y.rrr.Alnrost every induitrial con y I o n n u,"s' i re,;ffi ; li,: i} ? ̂?",:, I T",,:": l-?'i., Iil,,,?",il i "l littext j lc and in<. lustr ial alpl icat ions.

Nylon 6 arrd nylon 6.6 togethcr account for alnrost thc crr t i rcproduction of potyarnirte fibies. The ;;;s; ;; pffi,.ti"s orr"r",r201

F , F F F F F F I I F T F T F T F T F T F , II ' t A N D B O O K O F T E X T I L E F I B R E S

bv the two f ibres makes for great versat i l i ty, and there are few

text i lo f ie lc ls in rvhich nylon does not compete ef lect ively with

other f ibres. This versat i l i ty of nylorr 6 and nylon 6'6 has increased

steaclily over the years as research has introduced all n.ranner of

mo<.l i f lcat ions and improvements to the basic types of f ibre' Thc

procluct ion of t r i lobal f i laments and textured yarns in conr-

parat ively recent t imes, for exanrple, has opened up vast new

fields of appl icat ion for nylon f ibres.Since the end of Worl i War I I , cont inuous expansion of thc

,y,r th"t i . f ibre rnarket has bui l t up.the product ion of nylon 6

una nyton 6.6 into one of the world 's great new industr ies' An

enormous capital investment has been made in the nylon pro-

clucing inclustry; vast sums have been expended on the research

that .ii necessary to ensure maximum elliciency of production and

continuous inrprovement of the product. The result has been to

create an industry that is operating with great efficiency, and

proclucing two closcly-sinrilar types of polya-midc fibrc for wltich

ihere is i sustained and indeed increasing demand'

I f ei ther of these two polyamide f ibres, nylon 6 and nylon 6'6 '

sufferecl from serious deliciencies witlr respect to their suitability

for widespread use in the general textile field, the way would bc

op"n fo. ihe development of a more satisfactory polyarnide fibrc'

Lik" "ny other texlile fibre, nylon 6 and nylon 6'6 have short

lomings- with respect to their use in specific applications' But'

by uni lurge, the two nylon f ibres provide.a range of propert ics

tliat enables them to compete effectively throughout almost the

ent ire l ie ld of ,general text i le appl icat ions.ihis si tuat ior i provides l i t t le lncent ive for the introduct ion of

u n"* polyu.iae fibre to compete in the general textile field'

The prospeits are nracle even less attractive by the cost situation'

Nylon 6 an<t nylon 6.6 are now being produced by highly-ellicicnt

o-...t"t that are establisherl and thoroughly understood' Thc

economic conditions that infltrenced the choice of these two

poiyanri t les for cleveloprnent in the early day-s are st i l l val id

ioclay. The rnw nrutcr ials in each case are substarrces with 6

carbon atoms l inke<l in l inear fashion in thc nrolecule, and thesc

substances are inherent ly attract ive as raw nrater ials; they rnay

t. mu,l" by opening oul the 6-membered r ing of aromatic sub-

slanccs avai lable from coal, oi l and other sources'Unclcr present circunlstanccs, therefore, i t is di l l icul t to scc

how any othcr polyamidc f ibrc could establ ish i tsel f in dircct

N : S Y N T I I E T I C F I I } R E S

competi t ion with nylon { and nylon 6.6 as I gcncral purposctext i le l ' ibre. Thcsc two f ibres secnt dest incct to i .out inuc rs thctwo general-purpose poryanridc f ibrcs for as long as wc c: ' l sceahead. competi t ion wi l r .deverop not fronr a i r-cw'conrcncler, butbctween the two established

'fibres whiclr ,,f..",fV slrare thcpolyamide f ibre f ie ld betwcen thenr.

Sinilarities and DifJerencesThe chemical structures of

.nylon 6 and nylon 6.6 are vir tul l lyidcnt ical , di f fer ing- onry in the arrangen't"ni oi ' t l rc atorns in rhcant ide groups, as fol lols :

- NH(CH,LcoNH(CH,)"co _ _ NI{(cH,),,NFICO(CH,).CO _Nylon 6 Nylon 6.6

There are di f lcrcnces also in thc nrolccular wciglr t distr ibtr t ionand thc avcragc nrolccular wciShts o[ t l lc two pni i iu.*, rcsult i r rgfrom the dillerences in po[,rnerizatio,, iJh;1;ues usc<] inlnanufacttrrc.Thcse structural rc lat ionsh ips . bctwcc n nylorr 6 and nylon 6.6are ref lected in thc rclat ionships bctwcen t tr" t*o f ib i"r rp, ,n tronl

|11", RolVrn..s. .In general. terms, the characteristics of thc twororcs are srnr lar, and trrey ful f i [ s inr i rar rorcs in thc text i rcindustry. But there are diffeienccs i,, tf," pi"p"rii"s of the libres,rvlr ich vary in pract ical s ignr lrcance accordirrg to thc requircntcntsof part icular end-uscs.Sonre of lhe more jmoortant cl i lTercnccs bctwccn nylon ( andnylon 6.6 are as fol lows:( l ) Nylon 6 has a lower melt ing point (about 215"C.) rhannylon 6.6 (about 250.C.). For nroi t

^prnl t i in i- t"* t i tc purposcs,lhis is.not.a signi l icant factor. l -he "r i , f t i , ie

- ;" i " i "of nylon 6 isgcneral ly high enough to nreet alr normar .&r i ."nr*tr , but thcrcarc circumstances in which the higher n-,"fti,u poiirt"of nylon 6.6is advantagcor.rs.' fhc. lowcr

rncl t ing point of nylon 6 has bccn clainrcd torcsult in lower fuel costs during nrn n u fn.irr"-.-'Lcss hcat isnecded to keep thc polynrcr nrolteriduring r;i;;r;;g.*(2) Nylon 6 has a grcatcr af l in i ty for certain crycstut ls thanrrylon 6.6.. .Dycd togcrier with acict ' . ty; t ; ; i ; ; #nc <tycbnth,nylon ( wi l l dye to a shade several t in l" , . l . .p.r l f r . i ' thut uttnin.. l

203

' - )


by rrylon6.6. l lorvever, colourlastness is general ly better ortnylon 6.6 because the dye is ruore closely conrbir lccl with thef ibre.

' l ' rvo-tone (or rnult i - tone) dyeings rnay be obtained bydyeing fabrics constructed from both f ibres; s irni lar effects canbe nrore readi ly achicved by conrbinat ion of di f ferent var iet ies ofthe san te f i b re , e .g . , b r igh t and c lu l l ya rns .

l l lcnds of other f ibres with nylon, notably wool blends, mayoften be dycd rnore advantageously when nylon 6 is used ratherthan ny lon 6 .6 .. (3) l loth nylorr 6 ancl nylon 6.6 are sensit ive to ul traviolctl ight, and tend to undergo degradat ion and yel lowing to varyingclegrees al ter prolonged exposure to sunl ight. Resistance isaf ' fected great ly by t i taniunr dioxide and addit ives used to stabi l iseyarns against UV radiat ions.

(4) Nylon 6.6 has a better resistance to thc ellect of highternperatures i rrasmuch as i t has a higher melt ing point, and cnnwithstand highcr ternperatures without rapid loss of tensi le tndother propert ies. At tentperatures wel l below the melt ing pointof nylon 6, horvever, both f ibres wi l l undergo clegradat ion onprolonged heat ing, anrl resistance of nylon 6 to this degradat ionis grcater than that of nylon 6.6.

This increased resistance to heat degradat ion, coupled withthe lorver melt ing point, nrakcs i t possible for nylon 6 to be heldin a nrol ten condit ion without undergoing not iceable dcgradat ion.Nylon 6.6, on the other hand, tends to degrade fair ly rapidlywhcn held in a nrol ten corrcl i t . ion. This di f lercnce betwcen thctwo polynrers is i rnportant in i ts inf luencc on thc nrarrulacturcof f ibre. I t has proved sinrplcr to spin [ i lanrents direct f ronrnrol terr nylon 6 after product ion of the polyrner, without inter-nrediete cool ing and sol ic l i f icat ion, than in the case of nylon 6.6.

When sett ing fabric on a stcnter, nylotr 6 is at a disadvarrtagcin t l rat i t nrust be set within a closer ternperature range (6oC)than nylon 6.6 (20'C).

(5) Nylon 6 is clairned to have better elast ic recovery and fat igucresistance than nylon 6.6. Nylon 6.6 tyre cords, however, havc5uperior fat igue resistartce to nylon 6 tyre cords whcn each is' r i raclc to opt inrurn condit ions.

(6) Nylon 6 f i lar lcnts blend more readi ly than those of nylon'6.6. ' l 'h is

is an advnntagc wlrcn a soft ful l hand is requircd, but- is disadvantagcous when a cr. isp hand is required.

204

i_L__=^-,' n-"L ,'-r ft -L ' I n I r [ ' I

205

l t : s Y N I . l t E T l C r l l l R E S

(7) Ny lon ( r is nrore su i tab le for I l .F . rvc l t l inc thur r ny lon 6 .6 .

D i rcct Cottt ltcti I iortNylon 6 and n), [on 6.6 clevelopc<l into ful l_scalc int lustr ics urrdcrwirr- t i rnc cont l i t ions, ouc bccorning thc polyanric lc I ibrc of thcAxis Powcrs, and the other of thc Al l ic<l Powcrs. Wlrcrr t l rc warendcd each f ibre was establ ishcd in i ts own region of thc rvor l t l ,to the exclusion of the othcr.

I f thc di{ Icrences bctrvccn l l lc two nylons had bcen so signif i -cant as to give onc an intpressive advantagc ovcr thc othci . , ori [ the product iorr costs of onc ha<t bccn r i tuch lcss thln thosco{ the othcr, one type of nylon wour<i no croubr, rravc cstr trr isrrcdclcar ascendency after trre war c.<red. But witrr l i t t lc to crrooscbe tween rrylorr .6 and nylon 6.6 . in ei ther rcsl)ccl , t l r"r" ,un, , . , , ,i l rcenrlve lor el thcr sidc to switch product ion frorn t l rc f ibrc i thacl cstabl ishcd.

_ , ?, l l i " t po-st-wirr ycars, both nylon 6 alr<l nylorr 6.6 htvc gonc

lnei ld ' each rn r ts owr) l rart of the world. - l 'hc t l i l lcrcrrccs bctwccn

t i lc ln were insul l ic icnt to warrant a prcfcrcnl ial <. lcvcloprncrrI ofci ther; such di f lcrences as thcrc *"r" , i , . , fact, lor i t r ibut"d to thcrnaintainance of the status quo by nraking dycrs and othcrprocessors reluctant to changc front onc fibre to thc othcr rvhcrrl i t t lc tcchnical advantagc was to bc gaincd.

..." I i j|; l l.rl{,:l?y.lop.'nent.y.ears, ttrerctore, eactr type o f rrytonwas Dusy es tab i rs r l i 'g i ts pos i t io r r rarge ly or r t r rc bas i io r ' r r is t ' r i c r r lcevc lop l l te l l t . I l re s i tuat ion c l r lnged, howevcr , dur ing thc l9 ( r0sl:"d, 1?]!r: :11111 potn ty1,es.of rriyloiunacre il.ii;;;y i,, rcrrjtoryll lr, ym previously_ rcgardcd as the alnrost exclusive preservc ol.thc o ther . _ ln the U.S.A. , . fo r cxanrp lc , therc w ls no pror luc t io r ro f ny lon 6 in 1954, but 'by l9 ( r2 i f r i i n t r i . was accounU,rg t i , rsorne l0 per cent of the toial U.S. output. n,,J fry l9(r4, rr lylorr! g1y!: up about, 25 pcr cen.t of the ioral outprit . Vtca,rruhilc.prouucr ton o l ny lor r 6 .6^had bccr r rnak i r rg s i r r i i la r progrcss i r iGcnrrarry; by 1964, this f i lre rvrs accourrt i irg tbr abbut'_f J-pcicent o f the to ta l r ry lor r pro t luc t ion.

1'his p:tttcrn has bccn fol lowcd in otlrcr countrics too. Nylorr6 production.is now establishc<l in thc U.K., which rvas prcuioirslya nylon 6.6 preserve.

- .Wi th ny lon 6 anc l . ny lon 6 .6 now cornpc l ing r l i r .cc t ly w i th cachorncr ln rna10r world nrarkets, thc tech^ici l l di l l 'crcnccs bctwccrr

n - [

r , r n n t t t t t r F t F F F FI I A N D I } O O K O F

' T E X ' I ' I L D F t B I I t ] S

thcnr are becouring of greater signif icancc thau bcfore' The costs

of procluct ion, too, are being scrut inizcd -with the greatest care'- t ieqr i te the haridicap of i ts lower softening point, nylon 6

npp"nit to be making headway against nylon 6'6 in many

"ountr i .s, including the U.K. and U'S A' l ts protagonists point

io th. . l .eper dyeing character ist ics, increased l ight and heat

stability as iescri-betl ibove' These factors have.given it the edge

o" nyfon 6.6 in spccif ic appl icat ions, such as tyre cord' The

softei hand of nyion 6, too, has beeu o[ advantage in sonre

appl icat ions, such as tr icot fabr ics, and thc prodtrct ion of fabr ics

from falsc-twisted Yarns.With onty ot. t" r i* matcr ial to be made, compared with trvo

in the case of nylon 6.6, i t would seenl that nylon 6 product ion

shoulcl be simpler and cheaper than that of nylon 6'6 ' A new

route to caprolactam from toluene has increased the advantage

;; t j ; t .J by nylon 6 in this respect. on the other hand' i t is

claimed that <liarnines and diacids are cheaper to producc than

amino acids, giving nylon 6.6 an advantage in costs '

The extra leat- stability of nylon 6, allied with its lower

melting point, have made the development of continuous processes

simplei . 'Nylon 6 is now being spun direct f rom molten polymer

os it is pto,lu"ccl. 'I'he high nrelting point of nylon 6'6, and its

tendency to decompose i f hel t t in a molten condit ion, have made

itr . J.u.topnt.nt oi cont inuous spinning processes more di f f icul t '

With so many technical and ccononric factors involved, i t is

difllcult to preclict what the long-term result of competition

between nylon 6 and nylon 6'6 wi l l be. In the lneant ime, i t can

be forecasi with some certainty that nylon 6 and nylon 6'6,

between them, wi l l be the nrainstay of polyanride f ibre produc-

t ion for some dccades to come.

Otlter Polyanide Fibres

With nylon 6 and nylon 6.6 so wel l establ ished, and with the

..ono,r l i . , weighted io heavi ly against the introdt lct ion of new

gcncral pt trpose polyamitte f ibrcs, thc prospccts of devcloping

i.* potyonl iA" f i6rei are obviously restr icted. The opportunit ics

nlust l i ; very largely in the direct ion of producing special ized

types o[ polyamiJe hbre which can serve in part icular appl ica-

t ions foi rvhich the regular nylons (and othcr f ibres) are

inade4uatc.

206

I J : S Y N . r I I E ' T I C F I N I { E S

. Al l f ibres estabrisrr a place for t l renrsclvcs in thc tcxt i rcindustry by oflering a rnngc of propcr.ties tf* ,iiif.i. to r grciltcror lesser degree from the property ranges of othcr r ibrcs. -r .hcuscr assesses the character ist ics of every I ibre and sclccts thatrvhich of lers hinr the rnnge of propcit ics bcsi sui tcA to hispart icu. lar nceds, at the pr ice he can al lorr l t " ; ; ; .

'

lnevl tabty, the charactcr ist ics of any indivi t lual f ibrc rvi l l str i tsonre appl icat ions better than othcrs, arrd for c.r iair i appt icat ionsthe rangcof properties it orTers *ili b.-.;rtit;ly unsuitaurc. Thcdema.nd for any fibre depencls upon irs ;;.i;;, ';;;d

upon rhcbrcadth of . the spectrurn of tcxtiie ^plrii"'"ii"," ior wtrictr itscharacter ist ics are sa t isfacrorv.ln the case o[ thc nolyarr i ic le f ibres, nylon 6 and nylon 6.6,the inherent charactcr i i t ic i of thc f ibrcs r i rJ" i in. , . r" . , r , of r widcrange of imporranr text i lc appt icat io,rs, , , ix i ; i ;

' ; ; , " , nrc pro_auced on a largc scalc to nreet thc rest i l t i 'g,r ; , ; , , ; l . , fhcrc.r .c,

holcvcr, spcci f ic nppt icar ions for whicir i i i . ' , r , ; ; : i1;" of rry lorr 6and nylorr 6.6 are inadcquate, an<l i , . , ,port . i l i - i roi" l i t i r I nrrrkctsll'rny^9" cl-ose<t on rhis account. f " .rfri'"".*rllt'ii,r"i w"lr trc tt,"t:T, l.^�:"_fl l l . to nrcel rcquircnrcnrs try o,,ly', i *ingic facror; rtrcc,nd.-use. nray rcquirc, for cxarnple, that thL f ibrc shotrld rctairri ts tcnsile characterist ics at a tcnipeiatur" tr iglr" i i t ,oi i t trc rnclt inSpoint of the f ibre.

I f the end-use, in an example such as this, rcprcscnts arri:,"r-";:T:"1.3j."lll,:r Lll!:I. ro.'ti,"- nu,.,'ir,",",i,'Ii,i,liill]r,,'j:ir^"^1"_i-ll"dlicing a spccializ.,l iorn., oi poiv""ii,i" r" .iiili,ir,ldcf i .c iency in thc propeit ics is made goo<1.

],J:,lg^i1:! this type of backgrouriJ itat n.* polyanridc fibrcsi,i" :: i1q

dwelopcd, and.rhc oiproo"r,' i .,-Li;;; ' ;;;1j. rron, rwo*::; ll:.T r:.^o:,,-'l: " n" .n o n.t,' ili" "ri Ju.r,.,t" ;;;"";.

",;;;' ;:

T:1:n:1-"]".ically or physicaily r" rn"",'rp"Jnc',,i..rs. On tt,.:l,l:, l^119,",1.w types of nylon ^."-Uli"e p"iJu." j,'*r,i.r,,rir.rchemical ly from r iy lon 6 and nylon 6.6.

NOMENCI-ATURE

'l-hc- ternr 'nylon,,

as coinccl . by..<l rr l )ont, wrs clcf incd as . l gcrrcr ic:::]]],^t1::.: I l"ng-crra in synr heiic por vn," i j.. *i, i.ii'1,n,r"."ur.ri n ganl lde groups as arr in lesral-part of t l ie rrrairr l lo lynrcr chairr , anclwhich is capabre of being formed ri; i ; ;"fr;rff i i , t irr wnicrr rhcstnrctural elenrents are ori-ented ln tne aiieciio,i oi ifr. n,,ir,.

207

I T A N D B O O K O F ' I ' E X T I I - E F I B R E S

I ' r ior to the introduct ion of polycaproamide f ibres ( ' l 'cr lon L')

in Gert lany, the polyhexamethylene adipant ide f ibre dcveloped

by t lu Porrt in the U.S.A. was the only f ibre of comnlerciali r i rportancc that came within this dcl ini t ion of 'nylon' . Through-oui thc wart imc years, the du Pont f ibre was known sinrply byth i s nanrc .' l 'hc

devclopmcnt of 'Perlort L ' , however, brought anotherpolyanride f ibre on to the nlarket, and this I ibre too could be

described as'nylon' under the ternr inology establ ishcd by du Pont.

Clearly, sonrc tnethod of di l lerent iat ing betweetr these twopolyamide f ibres, and others which have since appeared, becanrenecessa ry.

'fhis can be done most ellectively and precisely by referring

to the polyarnide l lbre in ternrs of i ts chemical structure; theoriginal nylon, for exarnple, is polyhexa nlethylene adipanride'and 'Perlon L' is polycaproamide. This ternr inology is too cum-bersoure, howcvcr, for cvcryday usc, and a sinrple tncthocl o[nomcnclerture rvas dcviscd which retained the accepted ternr o['nylon' , but dist inguished between the di f lerent fornrs ofpo lyamide .

Using this nontenclature, the nunrber of carbon atonts iuthe const i tucnts of the nylon are indicated by appropriate f igures'the cl ianr ine being considered f i rst in the case of a polyamidc

ma<.lc by condcnsing diamine and dibasic acicl . Thus, the or iginalnylon, made {rom lrexamethylerre dianrine and adipic acid, isnylon 6.6 - the diamine and dibasic acid both contain 6 carbonatonrs. The nylon made fronr hexamethylene diamine and sebacicacid, l ikewise, is nylon 6.10.

When the polyar l ide is nrade by self-condensa t ion of a singleconst i tuent, c.g. an anrino acid, the nature of the polyamide isindicated by a single f igure represent ing the nunlber of carbonatonrs in t l te molccule of the or iginal const i tuent. Nylon 6, forcxanrplc, is the f ibre made by self-condcnsat ion of caprolactanr 'i .e. 'Pcr lon L' (rrow known simply as 'Perlorr ' ) .

Copolynrcrs

In clcscr ibing copolytrers, the rnajor conlponcnt is nanred f i rst .fol lowcd by thc minor conrpol lents in ordcr of decreasing pro-port ions. The percentages of each component are wri t ten inpa ren theses.

r l

208

II

209

I r L ' L ' :-u

I I : S Y N T I I t r T I C F I T } R E S

In thc copolyntcr izat ion o[ _hcxant eth ylc rrc cl iarrr i t rc, at l ip ic nci t l114

s,ebacjc_ l:il fgl example, a resulianr pof Vnnii,r" dcscribcd

it , t ] l_ l?",6.616.10 (90: I0) would bc n .opolynr"r contaioing thco .o ano o . tU co rnponcn ts i n the p ropor t i ons (by wc igh t ) o f 90 :10 .

I;cdcral 7'racle Cotttrttissiott DefinitiotrNylott . A manufacturecl f ibre in rvlr ich t l rc f ibrc-[orrning

substa'ce is a lorrg crrai 'syrrthet ic polyar ' i r le i . wri icrr lcss trrarr85% o!. the anrirt-e (-colNH-j ri,,k;;;;^;;.^';ii..r,.a to t,uolt ronratic r ings.Arantid. A manufacturecl f ibre in which thc f ibre-fornring

:?9:tT9: is a .long-chain synthetic poryriii i ir, i i rvrricrr at rcastor,,oor rne..anilde l inkages (_CO_Nfl_) are attachcd t l ircctly totrvo aronratic r inss.

TyPES oF POL;MIDE FIBRE'fwo

types of l ibrc - nylon 6.6 and nylorr 6 _ donrinatc thcpolyarniclc fibre fiel<|. As alrer<Iy a"r.iirr.',f ii,.r" n.i',t," gcncral-l:_rpi:l!*: that rcprcscnt thc bulk of polyanrictc fibrc lroduc-i]::

,^1 i:_::i,

years, however, a numbcr of ncw polyanride fibrcsnxve assuntecl conrmcrcial irnportance. In somc Cascs, lhcsc havcalready conre into conrnrerciil productiorr; il ;iil; cascs, thcyl.::- :,] jl

r"d:r d,cvcloprnent, b u t ihow prosiects oi'acrricvi n g r"u tlntportancc ln due co u rse.ln this section of the Hanclbook, the comnrcrcial ly irnportanttypes of polyamide f ibrc are discuisccl as fol lows:

'

( l ) Ny lon 6 .6(2) Nylon 6(3) Nylon I I(4) Nylon 6.10(5) New types of polyanride Fibre.

( l ) NYLON 6.6

Nylon 6.6 f ibre is spun from. polyhex a nle t l ly lcnc adiparnide, apolyamide.made by condcnsat ion of hexamctf iy lcrrc 'r t ianr inc andadipic acid :

T I A N D B O O K O F

NH. (cH. )u t ' t x .

HEXAMETHYLENE

T E X T I L E I : I B I I ' E S

+ Hooc (cur)n coot-l

A D I P I C A C I DD I A M I N E

I+-- co NH (cH.)" r.+r co (cH.)o co NH (cu.)o NH co (cH2)4 co ---

N Y L O N 6 : 6

POLYH EXAM ET HYLEN E ADIPAMIDE

-fYPES OF NYLON 6.6 FIBRE

Nvlon 6.6 is producecl as mult i f i lanlent yarns' nron ol t latnents'

i ; ; ; i ; ' t ; ; io*, in a rvic lc rauge o[ counts and staple lengt l ts to

sui i v ir tual ly al t tcxt i le requirenrents'"" i . rr" ' i l i " ! aie avai lable' in br ight, semi-dulI and dul l lustres,

ona- *iitt additives such as optical bleaches for specialized end-

uses.""i1," prop.r,ies o[ nylor-r 6'6 fibres vary over a range which is

r ini i i "a 'by the inherent character ist ics of the polymer, each

rr^nri".i,jt". controlling his process to protluce.fibres that will

".i.f tp..in" reguiremeits. In general, commercial nylon fibrcs

fal l into two maln ",arres, (aI regular tenacity and (b) higl t

tcnaclty.' - 'Nyi ;" 6.6 is a thernroplast ic.nbt: : ol l t lcnds i tscl f wel l to

uhvsical rnodif icat ions asiociated with this property ' Crimpecl

; ; ; i " i ; ; i " ; ;J vorns of al l the [ar ' i l iar tvpes arc avai lable'

l\{odified Fibrcs

N vlon 6.6 f i lanrents are commouly procluced in round cross-

. . l i i " , r , - f r i , , -

i iL, l " , ot spccial (c.g. rnutr i lobal) . cross-sec(ion arc

,ro*-ouni lufr t" f rom several nranu facttr rers ' Bicontponcnt f ibres

i i "^ i i "r , ,vpes have been introcluced, and n'rany others arc

under develoPment." ' i i . . " .oai .ol modif icat ions of the basic nylon 6.6 f ibre have

introcl trcct l I rcw f i t rrcs wlr ich hirvc spccial c l tnractc r ist ics t l i f lc l ing

fronr those of thc norrnal nylon f ibres'

2 1 0

TRILOBAL

S Y N T I I E T I C F I I } R E S

CIRCULAR

fi,,l{i!:f,Jli ii',i,""f,,j11",?l',*i,i','."i"i,1l,Ti,,ll,."f i'"1,,",li, :i:iJliXl}t"fi:l{i.!l'{r:;'"","? ;i!t,T"i'J:t i,?'t,i.T*.:lrm I'lil.l ji{ *i t*llnsisional higtrlight cffccr,_ antr prints on uoiti-w"";;;;li 'i ',;ii;,r rabrics rravcru nusual clarity and dcfinitioh.

PI{ODUCTION

Reaclant SynthcsisNylon 6.6 polymer is made by condcrrsrt ion of t rvo subslanccs:(a) adipic aci<|, and (b) l rcxanrethylene diarnirrc.

l 'hcse start ing nrater ials ar.c synthcsizc<. l usual ly via orrc orother of three routcs.

(l) Cyclolrcxanol Route'rhis

is thc or iginal routc usccr i rr ' rakirrg trrc sta' t i r rg nr i l tcr i i r rsfo r ny lon 6 .6 , and i t i s s t i l l t he rou te by w l r i ch r r ruch o f thc

2 l l

I I A N D I } O O K O F T I ] X ' I L E F I B R E S

nylon 6.6 is tuade to<lay. The stagcs in thc synthesis are shown

below.Originally, cyclohexanol was made from phenol, rvhich was,

in turn, obtained from the benzene dist i l led from coal tar or

petroleum. The phenol is reduced to cyclohexanol by hydrogena-

t ion in the prescl lcc of a catalyst ( l ) .

Much of ihe cyclohexanol used today is produced by a more

direct route froni benzene, which is reduced to cyclohexane (2);

the lat ter is thcn oxidizecl by air in the presence of catalyst,

forrning a mixture of cyclohexanol and cyclohexanone (3)'

OH

t l

OH

4'\t l t

oPI- IENOL CYCLOI IEXANOL

( \ @ - a l o , f - F\,/ \-/ \,,,

BENZENE CYCLOHEXANE CYCLOHEXANOL CYCLOHEXANONE

@

NH2 CO (CH.L CONH 2

ADIPAMIDE

rnNH, CH, (CH,L CH, NH2

HEXAMETHYLENE DIAMINE

Nylon 6.6 Mononrers. Cyclohcxanol l{oute.

Cyclohexanol, or the mixturc of cyclohexanol and cyclohexa-

none produced by the second route, is oxidized to adipic acid (4).

l lcxi t ntct t t y lcnc dinrninc, t l tc secott t l stnrt ing tr tatcr ial , is nradc

[rorn adipic acid by thc lol lowirrg route:

) l )

ozc-:t l

@ _HOOC (CHrL COOH

ADIPIC ACID

@

cN (cH,L CN

ADIPONITRILE

E I . - " 1 - I . - l r - l , I r I t I ' - l . I - l r l r l r - l r - l - - r . l f - l

D : S Y N T I I E T I C F I D R E S

(a) Adipic acid is reacted with anrnronia [o fornr acl iprnr idc (5).(b) Adipamide is dehydrarccl to adiponitr i te (6).(c) Adiponitr i le is rcduced to hexamethylcuc di lnr i rrc with

hydrogen in the presence of a catalyst (7).

(2) Butadiene RouteButadiene is a basic raw mater ial of synt lret ic rubbcr manufirc-ture in the U.S.A. and i t is pro<lucc<l in grcat quant i ty fronrpetrolcun'r . I t is rnade into adiponitr i tc by l l re foi lowing routc(sce below) :

(a) Butadiene is chlor inated with chlor. ine gas, to lorrn dichloro_bu tene ( l ) .

(b) Dichlorobutene is treated with hydrocyarr ic aci<I, fornr ingl , 4-dicyanobutene (2).

, (c) Dicyrrnoblt : l . . i l I ryt l rogcnrtcd in thc prcscncc of cntnlyst,

to Iornr acl iponitr i lc (3).Adiponitr i le is t l ren convcrtcd into adipic ncid or hcxarlcf l ry-

lcnc dianrine by hyttrolysis or rcduct ion icspcct ivciy.

o -C H . : 6 9 - C H : C H .

BUTADIENE

CNcHr :CH - C l -1 , CH2 CN

DICYANOBUTENE

Nylon 6 .6 Mononrc rs .

Ct CH : CH - CH2 CH2 Ct

DICHLOROBUTENE

cN (CH,LCN

ADIPONITRILE

l lu tadicne I loutc.

@

o

(3) Furlurol Routc

Ftrr fural is produced in large quant i t ics frorn corn cobs ancl ol thul ls. I t is converted to adiponitr i lc by the fol lowing routc (scebclow):

Furfural is cotrvcr lccl to furan ( l ) nn<l this is rcduccd tolclr l l rydrofuran (2). 1 'rc l tnrcnt with hydrochlor. ic i tc i<I convcrts

2t3

s

aTETRAHYDROFURAN

cN (cHr). cN

ADIPONITRILE

Nylon 6.6 Monomcrs. Fur fura l Rou(c.

tetrahydrofuran to I : 4-dichlorobutane (3) whici t . is converted toadiponitr i le by trcatment with sodium cyanide (4).

Hexarlethylene diamine or adipic acid nray then be made fronr

the adiponitr i le as describccl abovc.

I'oll,nrcriza(ion-f l re condensat ion react ion that results in thc formation of nylonpolyrncr takes place bctrvccn the amine Srot lps on cach end o[the hexamethylene diamine, and the carboxyl groups on eachen<l of the adipic acid. I f the two reactants are mixed in exactstoichiometr ic quant i t ies, thc react ion could theoret ical ly con-t inue unt i l a l l the sntal l molecules had l inked together into onelruge nrolecule. This could not, of course, take place in pract ice,as the opportunit ies for amine end groups and carboxyl endgroups to meet and react dinrinishes as polymerization proceeds,and the mobi l i ty of the polymer molecules is reduced.

If the two reactants are nrixed together in quantities whichare not stoichionretr ical ly balanced, the condensat ion react ionrvi l l proceed in the normal way. But a point wi l l be reached atrvhich al l the end groups of one type have been rcacted, arrdthe end groups of the polynrer chains are now al l of the typeprescnt in the componcnt that wa-s uscd in excess' The poly-nrcr izat ion wi l l then stop.

The manner in which this imbalance of components affectspolynrcr izrt ion is best i l lustrated by considering an extreme case.I [ condensat ion is carr ied out, for examplc, using I molar pro-port ion of c l iacid to 2 rnolar proport ions of dianrine, the poly-n re r i za t ion w i l l r csu l t i n thc p rod t rc t i on o f a 'po ly rnc r ' con ta in ing

[l].uo ' o-o-

O F T

qr' I A N D B O O K E X T I L E F I B R E

o)--=:-r-

FURFURAL F U R A N

o

cr (cH2) c t

l : 4 - D I C H L O R O U U T A N E

214 215

I t : S Y N T I I E - I ' I C F I B I { E S

only three component resicl t rcs, with anrinc groups on cach cnrlof thc molecule :

H"N(CH,)6N HCO (CFI')'CONH(CH,,),'N I t.,

I f the proport ions of the two conrponents rre, say, I rnolarproport ion of diacid to 1.25 molar proport ions of dianrinc, i .c.4 diacid molecules to 5 cl iamine molcculcs, thcn thc polymcrformed would contain 9 componcnt rcsiducs. ' l -hc polyrncrnrolccule would again have amine groups at cach cnd, i rnd furthcrcondensat ion would bc impossiblc.

Two irnportant poiuts are eviclent fronr this cl lcct of vnryingthe balance of the components used . in the polycondcnsat io rrreact ion;

(a) a high degree of polymerizat ion wi l l be attaincd only l ryensuring that the balance of components is aclcquatcly control lcd,

(b) the dcgree of polymerizat ion attaincd ntay bc control lct lby using componcnls in carcful ty cnlculntct l non-st oich iornct l icgrroport ious, rcprcscrrt ing thc rcquircd dcgrcc of i rnbl l i r rrcc.

StubilizatiortIn Lhe product ion of nylon 6.6 polynrcr, i t is ncccssury (o ut lowlhe polymerizat ion to proceed unt i l an adequatc dcgrcc o[ poly-nrer izat ion has been attairrecl . Polyntcrs bclow a rnolccular tvcightof about 5,000 wi l l Iorrn l lbres only with thc grc^tcst di l l icul ty;polymcrs of molecular weight between approximatcly 5,000 nnd10,000 wi l l form f ibrcs which are general ly too wcak for prnct icalruse. l t is not unl. i l t l rc molccular weight is grcatcr thl t r about12,000 that f ibres of adcquate strength arc produccd. I t isnecessary, therefore, that the polynrer izat ion condit ions should bcsuch as to al low this degree o[ polymcrizat ion to bc rcirc lrcd.

As the degree of polynrcr izat ion increascs st i l l furt l rcr, howcvcr,new dif l icul t ies ar ise. ' fhc polymer becornes iutransigcrrt anddit l lcul t to melt and spin. In pract ice, i t is rreccssary to corrtrolthe polymerizat ion to providc a polynrcr of avcragc nrolccularweight in the region of 12,000 to 22,000 thc actual f igurc bcirrgdetcrnr ined by the f ibre character ist ics t l rat arc rcqui lcd.

I t is apparent that the polymerizat ion rcact ion carr bc con-trol led in this way by trsing cxtremely highly puri f icd conrl)oncntsin very carcful ly calculatcd proport ions. I ly sui tublc choice ofthc balancc of conrponcnts, the polynrcr izat ion rnay bc stoppcdat any r lcsircd <lcgrcc oI polyrncr iza t ion.

I I A N D N O O K O F T E X T I L E F I D R E S

This technique is, in f lct , used in pract ice. A conrnrou ntodif icr-l ion is to crcatc the nccessary inrbalance by using sl .oichiometr icproport ions of the two components, and adding a sntal l propor--t ion of a nronofunct ional ingredient which serves as a chain-growth stopper in the slrne way as the extra proport ion of a conr-ponent. Acct ic acid, lor example, is added to the nr ixture ofhexamethylene diamine and adipic acid uscd in producingnylon 6.6 polynrer. The amount of acet ic acid is calculated toblock the cnds o[ the polynrer chains aftcr the dcsircd averagenrolecular weight has bcen reuched. Tlr is tcchnioue is cal lcd'sta bi l iza t ion' .

P olycottde nsatio rt

I f the hexanrcthylene diant ine and adipic acid are pure, thcymay be mixed in stoichiontetr ic quant i t ies direct ly in aqueoussolut ions, thc cr luivalcnce being clctcrminccl by elcctrometr ict i t rat ion. ' I -his solut ion is therr used direct ly for the polymerizat ionlo nylon 6.6 polymer.

Thc correct stoichiornetr ic balancc bctweerr lhe two col l l -ponents may also be obtained by react ing thc two mater ialstogether to form a salt , hexamethylcne dianrrrroniurn adipate, inwhich one molecule of each component is present. This ls com-monly cal led 'nylon salt ' .

-t_ -1- -

(N I-I3 (CH')oNH.XCOO(CH,),COO)

Nylon salt is prepared by neutral iz ing solut ions of the twocomponents in rnethanol. Tlre sal t is rclat ivelv insoluble inmethauol, and i t crystal l izes out as the solut ion.oolr . Tlr" crystalsare separated by centr i fuging, washcd and dr ied.

Nylon salt produced in this way is extrenrcly pure. Jn i t , thetwo nylon 6.6 conrponents arc pr.esent in exact stoichiometr icproport ions. The salt is dissolved in watcr to form a 60 per ccntsolut ion, and acct ic or adipic acid is added in amount calculate<lto stop polymerizat ion at the desired stage.

Condensat ion of the aqueous solut ion of nylon salt as carr icdout in a stainlcss steel pressure vcssel, using an inert atrnosphcreof ni trogen or hydrogen to ensure that oxygen is excludc<.| . Nylonpolymcr is extremcly suscept ible to deconrposit ion in the prescnccoI oxygcn at the tcnrpcralrrrcs uscr l in condensat ion, ancl i t isessent ial that al l t races of oxygen should be kept out of the vessel.

2t6

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B : S Y N ' I ' I I [ , T I C F I D I T E , S

Condensal ion is conrnronly carr icd out in two(l) 'fhe

solution is heatccl at 220-230" C. lorat a pressure of about 17.5 kg/crnz (250 lb/ inz).

s tages :

up to 2 hours ,

(2) lhe temperature is raiscd gradually, nnd steanr is allowc<l!9_.Iqlqg fronr the vessel, the pressure beirrg at about 17.5 kg/cnr2(25.0 lb/ inz). When the tenrpeiature has reaihe<l zis_zf i0dd., i l i .molten mater ial is held at this lcmpcrature at attnosphericprcssurc, or undcr vacuum, unt i l thc dcsircd dcgrcc of poly-nrerization has bcen rcached.

. The _m,olten polymer js then cxtrudc<I through a slit in thcb.ase of tbe vessel, the r ibbon of v iscous rnatcr ir j fal l ing on to aslow-moving wheel wlrich is coolccl by watcr. I-hc polynrcr isirnn.rediately chi l led and sol idi l ies to a tough r ibbon of hornJikcnylon . ,6.6 . polymer (polyhcxamcthylcnc acl iptrni<. lc), which isryp rcauy a t )ou t J0 c r r r ( 12 i r r ) r v i t l e and ( r r r r rn (% in ) th i ck .

. ' l 'hc r ibbon is passccr i rr to a nracrr inc wrr ich clrops i t iuto sr.rr i lpicccs or chips.

Spinning-fhe

spinning of nylon di f fcrs funt lanrcntal ly frortr tcchrr iqucsthat are used in rayon and acetate manufacrure. Viscosc rayon,for example, is spun by extrut l ing cel lulosc xanthate solut iontnto a coagulat ing bath which regenerates insoluble cel lulosc (wetspinning); acetate is spun by cxtrucl ing a solut ion of ccl luioscacetate in volat i le solvcnt into.a strcanr of hot air , thc solvcntevaporat ing to lcave a sol id f i larncnt (dry spinning). Nylo,, , onthe. other hand, is melt spun. The polynrer is l tcatct l i r r t i l ' i t nrcl ts,and the molten mater jal is then forcecl through holcs in spinrrcrcts.As the jets of rnoltcn nylon emerge, they arc-coolcr.l ancJ solidificclby contact with a stream of cold air , forming sol id l ihnrcnts.

In the melt spinning of nylon 6.6, grcat iarc must bc takcnto avoid the r isk of decomposit ion whi ih is always prcscnt whcnthe polymer is molten and at a high tcnrpcra[, , r" . A. in th"polymerization process, the polymer is alwriys protcctcd cluringspinning by maintaining an inert atrnosphcrc of, i i t rog.n or otheiprotect ivo gas above i t . Thc spinning techniquc is such as toma in ta in a sma l l amoun t o f po lymer in thc n to l t cn s tn tc t t nnyI inrc,_-so that thc opportunity for <lcconrposi l ion is i r t n rninirnrrrrr .Dctai ls o[ thc spinning operat ion arc shorvn in thc f iqrrrc orr;tage 219.

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N Y L O N

P O L Y M E R

Nylon 6.6 F lov Chart . Lcf t : producl ion of polynter '' ltll8il. ilii;lll'i,nvlo'�r

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E X T R U S I O N O F N Y L O N

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W I N O U P

COLD DRAWING

I I N D D O O K O F ' I ' E X T I L E F I I ] R E S

The yarn cn' lcrges fronr t l te cool ing chatnber at the rate ofsonre 1,200 metres per nr inute. l t has beert cooled to about 70"C.I t the dry, rvarrn yarn were wound direct ly at this stage, i t wouldsubsequcnt ly absorb nroisture from the air and increase sl ight lyin length. This would create instabi l i ty in thc package. Afterleaving the cool ing chamber, therefore, the nylon f i lanrents entera conditioning tube through which steam is passed. This moistensthe yarn and allows it to reach a state of equilibrium with respectto nloisturc it would otherwise absorb from tlte air.

The f i lanrents emcrging from the condit ioning tube are broughttogcther and given a sl ight twist before being rvound ou to thepackage.

Drawing

At this stage, thc long nrolcctt les of nylon polynrer are folded andin a state o[ random orientat ion.

' fhe f i lamcnts are weak and

opaque. In order to develop thc inhcrcnt l t rstrc ancl strcngth o[the nylon, it is necessary to bring the molecules .into alignmentwith respcct to the long axis of the libre.

-flte filaments are there-

fore stretched or drawn.Drawing is carr ied out by a technique sint i lar to that used. in

the product ion of rayon. Tl te undrawn yarn is passed rouud apair of feed rollers which control the speed at which it leavesthe package. I t then passes several t inres round a second rol lerwhich is rotat ing such that i ts surface speed is four or f ive t inresfaster than that of the f i rst feed rol lers. The f i lanrents of nylonin the yarn are thus stretched to four or f ive t imes their or iginallength as they pass fronr thc first to the second rollers, themolecules in the f i lanrents being drawn into al ignrnent.

The drawn nylon is lustrous and strong. l t may now be heat-setin boi l ing water bcfore being wound, or i t nray be wound upimrncdiately after drawing.

During drawing, the dianretcr of the f i lamcnts has becn reduced,and they have acquircd grcat tensi le strcngth. The appcarance ofthe f i larnents has changcd; they arc now trunslucent arrd lustrous,whereas the undrawn yarn was dul l and oprque.

Thc plrysical propcrt ics of the nylon yrrn produccd in this wlywi l l deperrd to sonlc dcgree on thc clegrcc of or icntat ion of thcnrolccules. This, in turn, depends upon thc clrnwing or stretchirrgto wlr ich thc f i l t r r tctr ts l ravc t lccn subjcctccl . ' l 'he clraractcr ist ics ofthe f ibrc can thus bc control lcd during nranufacturc.

' l ' l

221

S Y N ' T I I E T I C F I N R E S

I ' t tocEsstNc

Scouring

N{ost processing agents and rnany typcs o[ dir t nnd soi l arerenroved easi ly from nylon by scouring. Sornc typcs of soi l , how_ever, including graphite and certain oi ls and grcascs may bcdilficult to remove, especially if the soiled nylon is subjectcd to aheat-sett ing treatment before scouring.

Everything should be done, thcrefore, to kccp nylon clcanduring mil l processing, and nylon f :rbr ics shouid bc scourc<lbefore heat-setting to remove substances that rnight contributeto yel lowing during heat-sett ing.

Method

Nylon should be scoured with mi ld agit : r t ion at a nrodcratctcmpcratrrre, e.g. 50-60"C. Suggcslcd scouring fornrulns nrcgivcn in the tablc on pngc 222.

High ternperaturcs wi l l usual ly incrcase thc el lcct ivcrrcss of thcscour, and cause part ial sett ing of thc f lbr ic. Wrinklcs or crc:rscsset in thc fabric during a high ter lpcrature scour rnay bc di l l icul tto remove in subscquent opcrat ions.

Yarns or fabrics carrying a polyacrylic-type size must bcscoured before heat-setting, as it will be inrpossible to rcmovethe polyacryl ic acid after heat-sett ing.

Tho renroval of graphite becomes nrorc difiicult with tinrc,and nylon lace should be scoured bcfore storage.

Equipnten!

Jig ScouringThe jig may be used for scouring wovcn fabrics mltle frorn

f i larnent yarns, I t is advisablc to remove crcases by slcam franrirrgbefore the fabrics are loadcd into the jig.

Ileck ScouringThe bcck is used for scouring most spun wovcn f i r t rr ics, sonro

warp knit fabrics, and somo light and looscty wovcn filarncutfabrics.

Beck scouring is not rccommended for most hervy or t ight lywoven f i larrrent fnbr ics because of wrinkl ing an<l subsccfucrr istreakirrcss.

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222

B : S Y N T T I E T I C F I B R E S

The beck should not be overcrowdcd with fabr ic, i t r ordcr toprevent wrinkl ing.

Rotary Drum or padtllc Machine ScouringThis method is usccl nrainly for scouring knit goods such assocks. and sweaters, which arc usual ly placct l in bags bcforcscouring.

Ilopc Soapcr ScouringThis machine is usecl for scouring severcly soiled fabrics o[selected constructions which have a-high resistc-nci to "r"asingor wrinkl ing and to sl ippage of yarns.

Beont-Dyeing Equipntent ScouringWarp knit fabr ics and sheer.opcn wcnvc fabrics arc conrrnonlyscoured on bearn-dvcirrn eqrr ipntcnt. I , I ighcr tcrnpcraturcs rnaybc uscd. than in bcck s-cotrr ing, rvhcrc crclscs ant l ropo runrkstcnd to bc set in thc f lbr ic at i r igh tcnrpcr l turcs.- ' - - 'Ant i- foaming agents are general ly ' n"""rr ,rry to cl i r ' i 'atccxcessive foanring whcn scoui ing * i i r , ,v,r i i , . i i i dclcrgcn(s onbeam type equipment.

lllcnchirrgNylon is a white f ibre as producecl by the nranufactt trcr, andTl1:,1 r:o:rir"s bteaching. It a btuish_whit" "uri i, ..quircd, rhisnray De achreved by t int ing witrr a smai l ar.ount of a sui iabrcDruc or vlolet <tye, such as .Latyl ' DIuc I tD.,. Bleaching may bcqome necessary when fabrics are stained orlX:P::g during processing. Scourins rt;;i;i;i;"y, prcccrrc,r.1"1:nlnS.

rn such cases, as blcaching alonc is not always cflectivci1l : : l lo" l"S

certain. types of srains, especial ly oi ls anct greases._T ,some

cases, bleaching may set the stains in a nylon fabiic andnraKe comptete rernoval i rnpossiblc. I t may cvcn bc ncccssary,thereforc, to_ spot or clry clean thc faUric pr ioi- io l .our ing o,, . tbleaching. Nylon shoulcr be breached only *tr"n t i ie

-Jiscolorat io,

rcsists removal by scou r ing.

I 00 pcr cent Nylon y arn.r ond FobricsAcid Sodiunt Chlorite Bleaching100 pcr ccnt nylon is blcachcd nrost

thc acid sodiunr chlor i tc rncthocl. . fhis

223

cffcct ivcly [ry nrcans ofnrcthod is uscful as n

I I A N D B O O K O F T E X T I L E . F I I } I I D S

bleach for ( l ) nraxinrLtm wlr i tencss, (2) renroving yanl l ints, i lnd(3) whitening fabrics that have been yel lowed by exposure to air athigh tempcratures. Fabrics should be treated in opcn width fornrto prevcnt wrinkles front being set by the hot bleaching bath.

Pcracclic Acid Bleacli ngThis technique produces a good white with nylon when only a

l ight or moderatc colorat ion must be reduced. I t has the addecladvantage of being less corrosive to equipntent than the aciclsodiunr chlor i te tcclrniquc, and there are no toxic fumes.

Hydrogen Pcroxidc; Sodiunr I:ly pochloritc

Thcse are not el lcct ive bleaches for nylon, and they shouldnot bc used . in high concentrat ion or at c levated ten)peraturesfor long periods of t inre. Some degradat ion of nylon may takcplacc under such condit ions.

I- ] lcnds of othcr f ibres with n1, lon r lay rccluirc Lhc usc of thcscbleaching nater ials; in such cases, the condit ions of t i t .ne. tem-perature and conccntrat ion should bc l icpt as nrodcratc asp oss ibl e.

Blcttrls ol N)'lon and lla),otr

Blcach as for 100 per cent nylon.

Blcnds ol Nylon and Polyester Filtrc,r

Bleach as for 100 per cent nylon.

Blettds ol N,tlott and Acrylic Fibrcs

Bleach as for 100 pcr cent nylorr.

B lends ol Nylon ond Acetate Fibrcs

Bleach as for 100 per cent nylon, except that temperature shouldnot cxceed 77"C.

Blcnds ol N)4on and Wool

The acid sodium chlor i te blcach recommended for nylon wi l ldamage wool, and cannot thercfore bc used for blcncls of nylonand wool. A blcach is cotnmonly used, such as a hydrogen

224

- - l T - t . - t - l r - I . l . l . l

B : S Y N T T I E l ' t C F I S , { E S

pcroxide/telrasodiunr ovro.phosphate bleach at 50"C. . l_his wi l lbleach the wool, bui

- wilt have ritti"

'.h."t -i,, tt.,. nyloncomponent.

Rlends of Nylon and Cottott

bleached wirh (l) acicl so<lium chloritc, (2)a cont inuous unit or k icr, or (3) sodiurr i

These blencls can behydrogen peroxidc inhypochlor i te.

Acid sodium chlor i te i : : : : .d to rernovc yel lowing fronr nylonwhich results from hcat_s_ctting, as ncithcr of thc othcr twobleaches will be erlecriv". u"ot_iuing ;;;;;;.;ir'icquirctl whcna blended fabric contains 50 p"r c"n-t 1."_or"'Jf ',rur"".

Dycing(l) 100 per ccnt NylonNylon has al l in i ty for nrtny. c lasscs o[ <lycs, nrrt l nrny bc dyul1y.11c_ltuttr .wittr a_ vcry .wi<tc .n,lg"- oi-jy.rtrtir. t._or. urortpurposes, nylon is dve<t with dispcrsle "; ;;i,i';;. ctasscs, rhclal tcr includine nculral-clycing prcmctal l izcd and,chrornc dycs.Selc.cted direct dycs are used, and va[ dycs nray sorrrcl inres bc"oll1o: "3T.o.nty on bren<ls ot "vro,' "ijl";i;;i.

'rurne tnanutacturers have_ introducctl nylons wit lr specit ldyeing cha racteristics. These. h";;'" ;;d-e-;"..i,riJir," prort ucr iorrof nrutricotour. eficcts in singrc-uoit, ,ty-";";;i';;; ilr ccrrr rrytorr

Disperse Dyes

Llr,.: : ."* cspecial ly suited

_to tfc-dycing of nylorr, an<J thcy arc

:jo.:j.1,::":l i,l .ar..inU yarns arrd rorrri..I-ii"v'i,lo,vi<lc a rnctlro,Jor dyerng that is both simple ancl practical. , ,

As in the case of aceiatc anj poiv".i.. fibrcs, thc rlyeingi:::,1.T'i .is one of sorid sorutioir.-iillr;'ilvc cxccncnrrcveulng or transfer oronerties, and. proclucc t.i,. i *.tt-p.n.trot.,tav:ing:. Fastness to-ligtrt .,,a' *n.l, ini"i l;,,1r,,i";:;,,,.

Shade bui ld-up al lows l ight, nrcdiurrr ant l sornc dlrk shndcs.Acid DyesAc_id, neutral-dyeing prenretal l izect,cnrome and.sclccted direct dyes arcness rs required, or whcrc depth of

acid<lycing prenrctal l izcd,tusc<l wlrcrc nraxinr un.r f t rs l-shadc prccludcs the usc of

225


disperse dyes. Most of thcse dyes have good fastness to washing,beirrg superior to disperse dyes in this respect. Some havepart icular ly good fastncss to l ight. Chrome dyes are, in general,fast to soaping at the boi l .

Acid dyes do not transfer as wel l as disperse dyes, and theselect ion of dycs and dyeing procedure should be made withgrert care j f maximum lcvclness is to be obtainet l . This ispart icular ly true when f i lanrent nratcr ials are being dycd.

l{etarclat ion of the dyc ratc wi l l general ly give good resultsin achieving maximum lcvelncss. This may be done by ternpera-ture control , pH control , and the use of addit ives in the dyebath.

Acid dycs are absorbed nrore rapidly as the dycbath lempera-turc is incrcascd, or as the pFI is lowerecl. ' fhe dyeing rate nraybe control led, thcrefore, by ini t iat ing dyeing at or near theneutral point, and then gradual ly raising the temperature andlowering the pH.

Dycba th add i t i vcs r t ray bc o I c i thc r thc nn ion ic o r c r t i on ictypes. fhe anionic addit ives i rre colourlcss surface-act ive agcntswhich provide anions which compete with the dye anions for.the arnine groups in the f ibre nrolecule. The cat ionic addit ivesprovide colourless cat ions which form complexes with the anionsof the dyestuff. As the dyeing temperature is approached, thecomplexes dissociate to release thc dye anions in low concentra-t ion, a condit ion rvhich favours level dyeing of the f ibre.

Level l ing oI rnost acid dyes is enhanced by increasing thedyeing tenrperature to l2l"C. in pressurized equiprtrent. Thistcchnique also results in increasecl perretrat ion ancl i rnproverl\\,et[astness.

Dircct Dy'cs

Sonre dycstulls of this class are used successfully for dyeingnylon; others are of l i t t le use. The useful colours are, in gcneral ,those which are similar in chgmical structure to the acid dyes,and they nray bc appl ied to nylon by methods sinr i lar to thoseuscd for ncid d ycs.

Direct dyestuf ls provide shades of good fastness to washingand to perspirat ion. The washfastness of these dyestul ls on nylonis bctter than t l rat of the samc dyes on cotton or wool.

Netttnil-Dycitrg Acid DyesAl l acid dyes rnay be appl icd to nylon at low pI{ , but sonre o[

226

B : S Y N T T I E T I C F I I } R E S

these exhaust wel l at neutral or s l ight ly alkal ine pl{ ; thesc arcdesignated as neutral-dyeing.

,_,f l : """ , i . j -ctycing (non-metal l izcd) acid dycs gcncral ly havclalr to good transfer propert ies an<I good wct iastr iss.

N e trtral-Dyeing prcmetallized Dycs' lhese dycs are rccomntencled tor dying raw stock arrd top, arrt lin cont inuous pad-dycing systcnls. f . i rc/can, tro*.u.r , bc appl icr lto nylon yarns in eirher skein orpackalefor; ; ; ; ; ; ; i ; spun nyrorrpiece goods. The use of these Ayes or i nfo,""ni 'vr ,r , r . is l in l i tc( lby their poor transfer properricsj "u.i, n f

-irign"i.,'nl"ro, u r.r.

Acid-D ycing pretnetalliTccl D ycsThe acid-dyeing prenretai l ized dye'chronracyt ' r l rack w is used

::"li"iffi:,ixLi,''ff -"i,i;nlilJli""::i,ij:ul:ihl;*,i:ltrsull ly frorrr t clycbuth contl irr ing fonui" u"j i i .

-" ' '

CltronTs I)1's.e'Pontachrome'

Black TA arrcl ,solochrornc, BIack WDIrA arcexamples of chrorne dves. used- with nylon. i i r t l 'pro,ru"" rr , l tb lack shades having excel lcnt ro, in"r .

" io - i igr, i , " iJ wastr ing an<lto al l wet processing.

Vat DyesThese dyes are used successful ly to provi<lc high wct and l ightfasrness in a goocl range sf .ri"a"rj ovfi"g l i cirri.a out i,,alkalirre solutions, using temperatures highcr tha' thosc uscd forcotton.

,,, ,Y1, !fs. nre. frequcnrly usccl on blcrrcls of nylon an<l cotronwrren outstanding fastness is_ dcsired. Vat dyes alonc giue n

;: i .r"#Ot. union in l ight an<l nrcdiunr .f iua.J-i, , well bierrdcd

D ilJerential Dye EfJeus

Y]illi._"I:l*d"eflecrs nray be obrainccl fronr a sirrglc dycbnrh t:ylt ,r1*,,"s.,I :

r j .nylo"n yarns with dif lcrcnt dycing "cl ia

ractcrisr ics.r . \_ . r . r ' rDres L t ( I . , lo r exarnp le , pror luce the fo l lo rv ing c lasscs o i .yarn : s tar r< lan l dve inc : decp dye i r rg (ac id dyc ing) ; l ia i i c dycab lc(acid -dye- resist i .

227

rtL '' I --l -_l --t --l -l --l --l -l

I I i \ N D I } O O K O F T E X T I L E F I B R E S

. lJy using conrbinat ions of these classes of nylon, rvhich di f feronly in their dyeing charac te r ist ics, the dyer can obtain colourand rvhi te, two-colour, three-colour and tone-on-tone effects.l 'he nrost versat i le of combinat ions is obtained by using deep dyeand basic-dyeable yarns on which cornplementary colours,as wcl l as colour and whitc ef lccts, may rcact i ly bc obtainc<.1.' fhe

sha<le on the basic-dyeable nylon should be restr icted lonredium depth, in ordcr to prevcnt cross-dyeing of basic dyes onto the.deep dye yarn. Also, the easicst Iabr ic to dyc . is onccontaining 50 per cent decp dye and 50 per cent basic-<lyeablcyarn; the greater the dcviat ion fronr these proport ioni , thcgreatcr wi l l bc the rcstr ict ions on shade contbin:r t ions that canbe achieved.

(2) Bletrds

I } : S Y N T I I E T I C F I D R E S

is possible to treat the nylon with a dyc_resist bclore blcnrJingwith thc wool.

(a) Neutral-Dl,eing Acitl DyesThesc are conrmonly usc<l for. dycing rrylon/wool blcnt ls, pro_

d ucing. sat isfactory unions, in palc io heavy shrrt lcs, nnd trr i l j ingup well. They havc good wetfastrr.r. n,i.l fair to good light-fastness.

(b) Level-Dyeing Acid Dycs

, , Yi" t of . these dyes _producc a good union on nylon ant l rvoolorenos f i l l lght to nrcdiulu shades.

(c) Acid-Dyeing prenrctalli4d Dyes

. The_se dyes are conrnronly used ou nylon/wool labr ics thathave been carbonized. They producc.unions i l rat havc l ightfast_ness in pale shadcs of l5 to.40 sun hours ( .Chronracyl, dy-cs).

Whcn dycr l ncutrnl or with fornr ic nci j , t l rcy t lo not lcvcl nswcl l as with sulphuric acid, but this nrrr i t bc u.scrt with grcatcare as. i t can damagc nylon. The clycbath pl_I should not bclower than .3.0, or degrldi t ion of thc i ry lorr ' rnr iy rcsutt .

(r)) Chrotne Dyes

_ As a class, chronrc dyes olTer the best lightfastness on wool.Except in a few cases, thcy havc a gooA tig'irif,isrncss on nylon,and they are therefore used to procluio selecicd shlcles on nyionTwooI blcnds.

f 'he blends may lre di f l lcul t to chrorne, as thc wool absorbs3l1ls9 proport ion of rhe chronrc froi l t f i " f rorf ' l , f "uui , iginsul lc ient for the nylon.

(e) Ncutral-Dyeing prunetallizc.r! Dres

- These dyes are nor. gencraily recorrrnrcndccl [or thc u'iorr-! , { : i l .g 9f

blcnds of nylon arrcl wool, as rhcy slrow prcfcrcnt ialal lnr ly I or the nylon. Sclectcd dycs wi l l , l rowcvcr, proclucc sol ic lshades on 50/50 blends i f thc dye al l in i iy of thc nylon hrs bccnreduced with a resistant pretrct tnlcnt.

Dlentls of Nylon nul Ccllulosic FibrcsSevcral . methods. of dycing nylon/cel lulosic f i [ : rc [r lcrrds nr iry bcuscd.. Union-dyeing, cross{yciug and sirrglc_f ibrc t lycing rrc al lpossible, thc choicc dcpcncl ing on the fai tncss icquircr:ucnts of

229

- l - [ , . I - l , - l ' . I - l ' - - l

Nylon is often uscd in blcnds with othcr f ibres, to providc fabricswith propcrt ics not attainable by using a singlc l ib ic.' lhe

fol lowing points should be consiclerecl when blends orconrbinat ions coutaining nylon are to be dycd:

(A) Desircd Effcct( l ) Union dye(2) Cross dye(3) Leaving one f ibre white.

(B) Type of Operat ion( l ) Ba tch(2) Cont inuous.

(C) End-Use Fastness Requirements.

Blends of Nylon and WoolNylon and wool have af l in i ty for the sanre types of dyes, buttheir absorption ratcs are differerrt. This faitor makei everychange of shade or fibre prolrortion a clilTerent clyeing probleni.Thc blocking of dyc si tes by onc or more dyes in a mixturcnray also be a di{ f icutty which must be solvet l by careful dyesclect ion. For thcse rcasons, i t is esscnt ial to test every coloir_cornbinat ion before crrrying out the dyeing.

. Cross-dyeing or dyeing one f ibre and lcaving the othcr un<lyedis. not gcneral ly a commercial proposit ion with nylon/rvoolblencls, as both f ibrcs take up thc sanre dyes. In sorne cases, i t

228

'--l --I

m-Fi lr,f lr'f f,,i lTt'f-l,l ft'i l',i l.l 1.,: ltl f'l l',iI I A N D B O O K O I . l ' E X f I L E , F l B l L E S

the fabric, thc avai lable equipment and the proport ion of l ibresin the blend.

Usual ly, the nylon port ion is dyed with acicl dyes, and thecellulosic llbre with selccted aftcrtreated direct dyes. Whennroderate washfastness is sat isfactory, disperse dyes are put onthe nylon and direct dyes on the cel lulosic f ibre.

Vat dyes may be appl ied to nylon /cotton blended fabrics inI ight and rncdium shadcs, trs ing a onc-step procedurc i I thcpcrccntage of nylon in thc blcnd is about 25 pcr ccnt or lcss.For heavy shades, or blends containing more t l tan 25 per centnylon, a two-step procedure is usual ly necessary. Acid or pre-mctal l ized dyes are appl ied to the nylon on the f i rst pass, andvat dyes appl ied to the cotton on the sccond pass.

Lilcnds ol Nylon and Acetale Fibre

These nray be dycd readi ly with cl isperse dyes. Acid dyes nraybe used to dyc the nylon and leave thc acctatc white, but thercverse is not possiblc,

Most of the disperse dyes produce strength and shade onnylon which di f fer f rom those produced on acetate. Only al imited number of disperse dyes produce good unions.

Subt le cross-dye el lects may be obtained by select ing dyeswhich have more aflinity for one fibre than the other.

Blerrds oJ Nylon and Silk

When dyeing thesc blends, a careful colour select ion is requiredfor union shades. Cross-dyeing is not possible.

Blentls ol Nylon and Polyesrer (P ET) Fibre

White reserve effects may be produced on nylon/polyester piece-dyed warp-knit ted fabrics. The nylon component is dyed withselected Procion or acid dyestuf ls, leaving the polyester f i lamentconrponent white. The br ightness of the polyester nray beenhanced by the subsequent appl icat ion of a f luorescent br ighten-ing agent to procluce a white comparable with that obtainableon 100 per cent polyester fabr ic. Level shades on 100 per centf i lament nylon fabrics are di l l icul t to obtain using Procion dye-stufls, but where the eflect is broken as in a striped fabric, theevenness of dyeing is perfect ly sat isfactory.

lJoth components of woven or warp-knit ted nylon/polyester

230

l l : s Y N1 . t . t ET t c F t t lREs

nrixture fabrics may be dyc<l usirrg a single_bath process whichis shorter. and cheaper thin_ rhc two_barh- t" . i i i i i .1 i" "o,umonlyused to obtain cross-dyecl ef fects.

The preferred nrethod is based on the usc of thc high-tcnrperature beam-dyeing nracrr inc, s incc i t rras bccn found t i iatunder these condit ions selcctccl dispcrsc t lyes givc a stain on thcnylon which is wcakcr than, or i t l "nr i no*hcirvicr thrr ' , t l rcsiadc on thc polycstcr f ib 'c corrponcrt . whcn t l rcsc sclcctcddyes arc uscd, thc fastncss of t l rc siuin on tnc uyton is at lcquatcf,o r a wide rangc o[ apparel out lcts. Whi lc thc j lcscrrcc ol thisorsperse-dye staln on the nylon cxcrts sotnc inf l rrcnce orr thc f i l ralshade which can be obtained, a wiclc range of i r t t -racr ivc colourcontbina.tions

_can be produced on the fin-ishcd fabric by cross-dycrng the nylon with. Nylomine ancl acid rni l l ing dycstul ls.

l r l ree-col n ponen t mixtures such as nylon / polyestcr /cotton mayalso_ be handled by thc onc-bath proicss, tut thc problcnrs oishl<lc control in bulk scalc workir ig rnlkc i t l t lv isrr l lc (o lcuvcthc cotton undycd. whcrc trrc cottor i is in an . int i rratc blcncr rvi t rrthe. nylon or polyester f ibrc, care shoulcl bc takcn in fabr ic <lcsignancl choice of colour to avoid exccssive contrasls whiclr rvoulcl: l l : I

u. . l r?l"hes of. changing colour as thc cottoir conrponenr isprctercnt lal ly abraded away in wear.Ccrtain textured fabrics, such as

Lrnsuitable for bearn-dycirrg, may bcmach ine .

Printing and Surfacc [flec(sN4any types of nylon fabrics nrcI lat-woven and nylon tr icot fabr icsrol lcr- and screen-pr int ing tcchniquesvanety of end-uses.

scerstrckcrs, which arehandled on thc rvinclr

pr inted conrntcrcial ly. Nylonarc pr inted by convent iona Ito mcet thc nccds of a grent

Nylon. carpcts, hosiery, special i ty fabr ics and ynrns are alsopnnred, but special tcchrr iques and equipnrcnt arc oftcn rcquircd.. A w ide se lec t ion .o f dyes i s ava i l ab le fo r p r in t i ng ny lon , i r r c lu r l -: i9 , ' " :"V,

acrd, drrcct, prernetal l izcd, vat and dispcrsc lypcs.l (esrn-bondcd pignrents arc also used. ' l -hc sclcct iorr of c lycs i iorrrany of these classcs shoulcl be bascd on thc crr t l -usc of thcfabrjc to achieve aclccluate colourfastncss ancl bi iglr tncss ofshnde .

Fabrics of nrul t i lobal cross-sect ion nylon :rnt l Schrcincr-calendered nylon tr icot fabr ics are espccia[ ly sui tcr l to pr int ing.

731

I I A N D B O O K O F 1 ' E X ' T I L E F I B R E S

The increasecl cover and smoothness of these fablics give clear

Jef ini t ion of pr inted patterns, good colour register, and more

desirable opaque backgrounds.Specilic

-foinrtrlac for printing pastes d.epcnd upon the type

of clye to be uscd, the method of appl icat ion, and the naturc o[

the iabr ic. Pastes to be used in screcn pr int ing are general ly

thicker than those for rol ler worl<. Fabrics o[ spun yarn requirc

a thiuncr plstc t l tan sheer f i lament construct ions'

Acid und Dircct DYes

These are widely used in pr int ing piece goods for dresswear'

They provide the br ightest shades that wi l l meet nr inimunr fast-

ness requircnrents for dress fabrics. Thcy bui ld up readi ly to ful l

shacles, and arc used for attract ive combinat ion shades.

N e ttr ral-tlyeing atil Acid'dyeing Prurte!ullit'cd D5's5

These types are dul ler than nrany acid and direct dyes' but

exhibit vJry good fastness on nylou fabrics. Thcy are used rvhere

nraximum l ightfastness and wetfastness are rcquired, as in

carpets, car upholstery and swimwear.

Vat Dycs

Selccted vat dyes pr int easi ly and produce shades with out-

standing fastneis to washing. Lightfastncss is commonly infer ior

to that of tho same dyes on cotton.

Dispersc Dyes

These dyes are econotnical to use with nylon, end posscss good

af l in i ty, bui lc l t rp ancl lcvel l ing pt 'opcrt ies. ' fhs shades are clr t l lcr

than tjiose prodtrced with aci<l dycs, and arc iufcrior to the acid

clycs in weffastness. They must be processed with.care to avoid

staining of whites during r i rrs ing for removal of thickener '

Ilcsi rrB oml ccl I'igttrcnl s

I) ignrcnts arc appl icd to nylon fabrics usui l l ly f rotn i tn cmulsiort

.ont, , in ing su[I ic icnt resin to bind the colour l rcchirnic"r l ly to thc

fabric. The ettr t t ls ion may be of the water- in-oi l or oi l - in-watcr

typcs. Thc pignrents are f ixecl to the fabric by cur ing thc resin'

Pisnrents are used in pr int ing slreer nylon fabrics and ir l t l tcprocl i r i r ion oI opaque white-on-whitc el lects which cannot bc

232

r . 1 r l r ' f I J r - I r l t ' I

2 J )

R : S Y N T I ] E T I C F I D N E S

produced by any other nrethod. Thc pr int nray bc st i l lcncd tosomc extent, but pigment pr int ing is usurl ly sat isfactory whcrethe coverage is smal l euough to lcavc t l re l rand of thc fubrictrnirnpaired.

Disclnrge Prirrting of Nylon

1-he discharge pr int ing oI nylon has bccn l i rni tcd by thc fol lowingfac to rs :

(a) Few dyes are sat isfactor i ly dischargeable on nylon.(b) Dyes which are dischargeable do not usual ly huvc sul l ic icnt

levelness to meet rnarket requirements.(c) Discharged areas havc a tendcncy to discolour with agc.Best results have bcen obtained with pastel shadcs, dischnrging

to whitc or to a colour with vat dycs in t l rc pastc.

Str ipping

Dispcrsc or acicl dycs nray be rcnrovcd frorn nylorr by:r str ippirrgproccclure based on a rcducirrg act ion, ' l 'hc

fol lowing is l rrrcxanrple o[ thc type of str ipping techniquc which may bc usct l :

1. Add thc fol lowing to the str ipping bath, basccl on weightof goods :Zinc sulphoxylate formaldehydcAcctic acid (56 pcr cent) or fornric acid for

heavy shades'Duponol' D Pastc or 'l-issapol' N surfitce

active ageDt

5 pcr ccnt

10.0 pcr ccrrt

0.5 per ccnt2. Str ip for 45 minutcs at BB to 99'C.3. Drop thc bath ant l r inse wcl l .4 . Scour w i th 'Dupono l ' D Pas tc , 'Dupono l ' l lA , o r ' l - i ssapo l '

N .I f this proccdurc docs not rcmovc aci t l <lycs complctcly, l l rc

fol lowing addit ional t rcatnrcnt rnay bc uscd:l . l tun at thc boi l for about 30 nr in. - rnisc 3'C. / rnin. i r r rr

so lu t i on con t l i n ing :Ace t i c ac id (5 ( r pe r ce r r t ) 0 .13 oz . . l g r . l . (0 .8 g / l ; 0 .1% so l r r ) .Sodium chlor i te 0.07 oz./gal. (0.a g/ l ; 0.057o soln) pl l to

6.0 to 7.0.2 . I ) roo the ba th and r i nsc wc l l .


3. Scour w i th :'Duponol ' RA 0.06 oz . /g ,a l ' (0 .36 g / l ;0 '05% soht )Sotl iunr bisulphite pyrophosphate 0'133 oz' lgat' (U'U g/l;

l0% soln).

Chcmical Finishing Trcatntctrls

Fabr ics at rd yarns of ny lon rnay bc made. sof ter , s t i f ler or repel -

i .ni to oit and water by trcatnicnt with the appropriatc typc of

i'r"irriiltg' agent. Antistaiic properties nray be iutparted to nylon

by use of an antistatic f inishing agent'- '- | t , . a"tnrotological behaviour of f inishing agents shott ld

nf *nV, b" chcckc-cl with great ctr t c ' as sot l le l1lay cl tusc skin

irr ' i tat ion or sensit izat ion.

NI odilicution ol Fobric II atrd

Nylorr fabr ics often unt lergo f inishing treatmel)t designed to

p.* i , f" incrcirsccl so[tness atrd i t l l l rovccl draping propcrt ics'

iog.th", with increasecl yarn pl iabi l i ty atrd surface lubr ic i ty '-7Auit .* ' NA and 'Cir iasol ' AD softetrcrs are examples of t l rc

type of f in ishing agent t tsed for this pt l rpose' I f morc lubr ic i ty is

. ' "q" i i .a, an eq"uat-part of 'Methacrol ' I -ubr icant K or 'Lubrol '

w" r i r"v ' f r"

. , r ied in aclcl i t ion to the 'Avi tcx' NA or 'Cirrasol '

AD. ' l - j rese f inishes arc appl ied by padding on a quetsch or by

exlraust ion fronr i r di lute bath. A l in ish level of 0 '5 to 2'0 per

ccnt is usu a l lY desir i tble 'Thesc trvo' f in ishing agenls arc also t tsecl to i rnprovc the

scwing qual i t ies of nylon iabr ics on high specd sewing tnachincs'

The a-nrount of f in ish appl icd is in the region of 2 '0 per cent '

Sorne nylon fabrics are treatcd with l in ishing agents to

ino.ns" st i i lncss of hancl le. ' l -herrroplast ic rcsin dispersio's, st tch

;;- ;Ei ; ;J; 8l-900 polvvinvl acctate and 'Methacrol ' FNI-I resin

,rirp"rrion nre .xanlpl"i of finith.. used for this ptrrpose' 'lltey-

" iJ utr ' ,ot tv pat l<. lccl bn thc goocls, to produce .concentral ions of

0.5 to 1.0 pei ccnt for sat i rrs and taffetas, an<l l '0 to 3'0 per cett t

for nrarquiscttes (based on the weight of [abr ic) '

I f a tnore clurable f in is l l is required, a lhcrnlosett ing resi t t

such as 'Acrolex' M3 maY be used.

Repellcnts

Coocl watcl rcpel lcncy is obtr ined by thc nppl ic ir t ion o[ 'Zelart '

S io nylo,] fnbi ics. . t - l ic rvaler rcpcl lcncy is durlblc nrrd rcsistant

234

N : S Y N T I I I J T I C F I B R E S

to launder ing i f p roper l y app l i cd . 'Zc la r r ' .S i s app l ied by pa< ld ingfrom an aqueous bath, fol lowcd by drying ancl cur ing at c lcvatct ltemperature.

Appl icat ion of. 'Zepel ' B fabric f luor idizcr to fabr ics of nylonand i ts blends w.i th other f ibres provide water- and oi l -rcpcl lcntand stain-resistant f in ishes which are durablc to both l i rundcrirrgand clry-cleaning. Typical i rppl icat ions involvc thc usc o[ 2.5 to3.0 pcr ccnt 'Zcpc[ ' B with rvl tcr-rcpcl lcn t l rdjuvunts l rnt l /or.resins sclected to rncet individual f in ishing rc<l uir .cnrcn ls. 1 ' l rcf inish is appl ied by padding, fol lowcd by drying ancl ctrr ing r t150'C. for 2 to 4 nr inutes. I t is not ueccssary to aftcr-washunless the forrnulas uscd contain resirrs or othcr nroducts whichrequire au a [ tcr-wash.

Atttistatic Finishes

An an{istat ic f in ish rvhich is clur.ablc to lnundcring rvi l l r soirp isnttuincd by applying 'Zclcc' DI, i r r t l tc r .urrgc ol ' I lo 2 pol. ccnlto nylon. The ef iect is ncutral izccl by cxpostrrc of thc treatc( lfabr ic to synthct ic dctergcnts, but i t nrty l rc rcgcncr:r tccl byr insing with warnl soap solut ion ancl thcn with wa(cr.

Ternporary ant istat ic f in ish is providcd by t l rc appl icul ion ofagents suclt as 'Avi tex' NA or 'Cirrasol ' AD. Yarns rvi th 'bui l t - i r r '

ant i -stat ic propert ies are also avai lable.Flarne RetardantsClean, undyed, f in ish-free nylon labr ics l rave lorv l l t rnrnabi l i ty,and in this respect are sat isfactory for nrany pract ical purposes.The f lanrmabi l i ty nray be increasecl, howevcr, by ccrtairr rcsirr-f in ish appl icat ions or by certain dyes. Such fabrics nray bctreated with f lanre -re ta rcla nt f in ishcs to rct luce t l rc ir f lanrtnlbi l i ty.Exanrples of these f inishes are 'Pyrosct ' Fire l tctardant N2 andN l0 , and 'F i -Re ta rd ' NBX.

Tlrese f lanre-retarclanls havc an advcrsc cl lcct on thc l ig l t t unt lgas-fading fastncss of dycd nylon. ' l 'hc

st i l l l in is^h which is oftcnprocluccd by a rctardarrt nray bc ntot l i f ic<l by n softcncr.

Mcchanical Finishing' frcatrncnls

Modif icat ion o[ the hand and surface lppcarancc of nylorr fabr icsmay be achicvcd by various rncchanicnl t rc l t tncnls.

' l ' l rc cl l cct

dcsircd in thc f in is lrcr l f rbr ic dctcrnr irrcs thc tygrc oI cr l rrrpr lcrrrrrscd.

235

I I A N D B O O K O F ' T E X T I I - E F I B I I , F , S

l. Cold Caluilt ritr!:

Calcndering is used to pol ish and smooth a fabric surface, orto minimize the nrark-of l of labr ics treated with resins or waterrepel lents.

' I 'he rol ls of the calender are normal ly unheated, and

pressures of 30 to 50 tons are uscd.

2. Flat Colcndcring - Tricot Fubrics

Flat or Schreiner calendering of t r icot nylon produces a durablef inish which increascs t l re covcring porvcr of the fabric andclrangcs i ts hand and appe:rrancc. ' fhe changc irr appcaranccresults fronr a cornpact ion of thc fabric st i tch and fronr di f iusionof light reflected from the embossed fabric surface. A change inthe fabric hand rcsults from a decrease in thickness of thefabric, ant l a change in the fr ict iorral propert ics of i ts srrr facc.Ful ly dr icd tr icot, calcndercd at zcro tensiorr, produces theopt irnunt f in ishcd cf lcct.

Schreincr calendcring can be uscd to:

(a) produce thin, l ightrveight fabr ics with a high degrcc of opacity,which retain goocl porosi ty and good burst ing strcngth;

(b) obtain excel lent whiteness with a ful ly delustred appearance;(c) obtain a more ef lect ive pr int base by . increasing cover ancl

smoothness;

(d) produce a trvo-fold increase in covcring porver of the fabric;(e) increase the styl ing potent ial of t r icot by changing i ts normal

jersey appearance.

In the Schreiner caiencler ing of nylon tr icot, the fabric ispassed through an engraved (diagonal grooves I l8-142/cm;300-360/ in) Schreiner calender at temperatures of 193 to205oC. a t 12 -27 m (13 -30 yd ) pe r m inu te . On a 122 cm (48in) width rnachine, good results are obtained at rol l pressures ofB0 to 100 tons .

Calcndcring nray bc carr icd out at any stagc during f inishing,but the cl lects obtaincd wi l l depcnd upon thc stage at whichit is introduced into the f inishing scquence.

Schrcincr calcndcring rcsults i rr excel lent opacity, thinncss,unifornr i ty of appearance, durabi l i ty, dcfect coverage and hand.lVi th scourcd or dyed tr icot, calendcring f lat tcns the yarn andc loses lhe s t i t ch , bu t w i lh l css sh r ink lgc than occurs w i th g ray

236

- l r t r - l r - l . r ' I r r I - - I

t ! : s Y N . l . t I E . r . t c F IU l tesgoods. Durabi l i ty and hand are excel lcnt in this proccr jurc, rv i{hopacity and thinncss rated as goocl.

Calendering has the least efcct on ful ly f in ishct l nylorr t r icot,as the goods havi already bccn hcat_sct ,,1,j i""r-iJ.f .r.piug. .l.hisjs the most economical wiy of.ScJrrcirr"r .;i;nl;;;;g nyron rricor,as intennediate drying and franring 0." unn.. .r* iy. Thc cf lcctson the fabric, howcver, arc only fair to gooc|, unJ i i , " calcndcringnray bring out u'dcsirablc lusire which-nrust ttr". trc t.ut., i i i frby subsequent wet working.

3. Etn bossittgN.yJon 6.6 may be durably crnbossed wi thout t r re usc of rcs ins.This is achieved by embossing at elcvatcJ tcnipcraturcs withclose control of the moisture contcnl of thc tabi ic, <lwcl l t i r rrcand roll pressure.

I^ rnost cases, i t is not .ccessrry to hcnt-scr srrnr low c.rbosscdprt tcrns.to obtain a last i rrg cl l 'cct . Dccp .pnttcr.rrs, horvcvcr, rcqrr i rohcat-sctt ing. Thc fabric shorr ld bc corr iplctcly," f , , i . j dur ing hcat_sett ing to prevcnr loss of rhc r trrce ct inr"rrsi f ; ; i ' ; i i ; , .

4. Napping and Sueding

| lnging and sueding. equipnrent is uscd to producc ruiscr l sur-

1119. ,onrnYlon fabrics,. t l rc conrl i t ions n.c".r . .y to obtnin aoesrred ellect on a particula.r. fabric being bcst ictcrnrincd byexperiment. Knit fabrics shoutd bc l"i."d";;,1i;;; ii 'rst to nchicvcnraximunr effect in atry rarslng operat lon.

, . , t \yton ha,s a higher tenacity than natural f ibres, and thc clot l r_

:1E l,:rT:,i|_1*d. on. nappcrs for wool or cotron fabrics nraynor oe oI adequate strcngth. St i l ler napper clot l r ing is usual lyrequired to.obtain a good napped .r . fo." on-, , nf ion frbr ic. zfsoftener act ing as a lubr icant, wct or dry, assists in raising f ibrcsto , thc su r face by rcduc ing in tc r_ f ib rc f i i " r i " i i . ' -

" '

uesl rcsults are usunl lv obtaincd in sucding by using thc f incrgrades of sanclpaper.

5. ShcaringFabrics of. spun nylorr nrrcl blcnd-f trbr ics corrt ; r i r r i r rg rrylorr rnaybc shcarcd to rcmovc exccss surfacc f ibrc. ln t i ic 'casc of pi lcfabrics, s lrearing is use<l to. .cut thc pi lc to a unifornr hcight.Shear sett ing. var ies, <tcpending upon f"b;L-; ; ; ; ; i ;cr ion, pi lcdcnsity and the dcpth of cut rcquirccl

t F t F r tri


Fuzz which is deeply embedded in the fabric construct ioncannot be removed by shearing, and i t may be necessary toremove this by singeing. This is preferably done after dyeing, toavoid deep-dyeing of melt balls.

6. Scntidecalers and Palttrcrs

Smooth, presscd fabrics are obtained by sernidecat ing or bytreat ing in a palmcr. Condit ions wi l l vary dcpending upon t l tcf inished ef lects requircd.

l . f l ea t -se l lu tp

Pleats nray bJ set in nylon fabric by exposurc o[ the plcateditenr to saturated steam at a pressure of 0.7 kg/cmz ( l0 lb/ inz ) for20 nr inutes. Several commercial ly-avai lable rnachines wi l l setpleats in nylon by exposing the fabric to a hot rol l . l t is essent ialthat thc fabric should not be hcat-sct before the pleat ingopera t ion .

I Icat-Sctt ing

Nylon 6.6 may bc hcat-sct before or after dyeing. l f this is doneef lect ively, i t wi l l have the fol lowing results:

( l ) Residual shr inkage wi l l be renrovcd, ensuring dir lensioualstabi l i ty of fabr ics during processing ancl wear.

(2) Resistance of fabr ics to wrinkl ing during processing andwcar wi l l be increased.

(3) Yarn twist wi l l be stabi l ized.

(4) Edge curl of fabr ics wi l l be prevented.

(5) Hand of fabr ics wi l l be softened.

Nylon 6.6 fabrics may be heat-set using ei ther ( l ) dry heat,(2) saturated steam under pressure, or ( .3) hot water ( l2l 'C.) .Thc degree of set is determined by both the durat ion and thetcmperature of the treatnrent, and the natule of the sctt ingmed iu m.

Nylon 6.6.tends to shr ink during sett ing, developing a force ofabout 3.5 cN/tex (0.4 g/den). A force equal to this rvi l l prevetrtshr inkage; a greater force wi l l stretch the yarn.

Wrinkles or creases formed during heat-sett ing or during dyeingof an unset fabr ic wi l l be alrnost impossible to rernove.

2 lB zJv

l l : s Y N T l . l E t . t c F I o R E S

l 'he select ion o[ a methocl _for hcat_sett ing nylon <lcpcnds onthe forn.r of thc l ibrc ancl on the propcrt ics AJsir l id in thc hcat_sctproduct. fhe fol lowing ntetho<Js are-conrnronly usccl :( l ) D ry Hear

(a) Hor Air(b) Radiant I- Icat ( lnfra I icd)(c) Hot Rol l

(2) Slturatcd Stcanr Undcr Prcssurc(3) .l-lot Watcr.

STIIUCTURE NND PROPEITTIES

liinc Structurc and AppcararrccNylon 6.6 f ibres are sntooth_s u r faccci , rv i t l r no slr i : r t ions. Innr.icroscopic appcarancc

.thcy arc n, r"ur,ii..t.r*r- ns grass rorrs.' l 'hc f ibres nrc cournronly. . ol . round .r ,r*-r ." i iuu, [ rrr l spcci l ltypes of nylon 6.6 of nrul t i lobar cross-scct ion ur. , r ' , r* produccd.

TenacilyThe te r rac i t y o f ny lon n ray be va r iec l w i th in l i r r r i t s t l y l t l i us t i r rpure nranuracturrng cont l i t ions. Fi lantent producct l foi st<ickingihas a te_nacity of 40.6-5 1.2 cN/tex (4.6_5.8 g/cle n), c lry;35.3"_45-0 cN/tex (4.0J.1-g/den), wet. t . l igh tenaciTy.rr f ton rrray have

l,.l:]]tri:I."f^]f s cN/tex (e.0 g/dei), crry; 2,s.6 .Nlt.i (i.ig/oerr), wet. Nylon staple^ has_ a- tei lacity of 36.2_39.7 cN/tcx(4.1-4.5 g/clen), dry; j r .s_:s. : cu/tei t j .c_+-.0 g/, i . " j , i " . i .Loop tenacity: about 90-95 per cent of noinral.Knot tenacity: about g5 per ccnt o[ nornral.'l 'cnsilc

S(rcngtlrl legular filanrent: 4.550_5,950 Ig/1,1,1 (65,000_85,000 lb/inz).I,tigh tenacity filament: c,joo_plioij rdl"iJiso,000_t 30,000lb/ i r rz ) .Staple: 4,200- 4,620 kgl crnz (60,000_6(r,000 lb/inz ).Iilongalion

Regr: lar f i lanlent: 26-32 pcr ccnt (30_37 pcr ccnt, wct).High-tenacity f i lamcnr : l9-24 per t .nL 12'1_2g f f , ""n,, ,u", t .Staple: 37-40 pcr ccnt (42-46 per ccnt, ' .uc0.

'

I I A N D N O O K O F 1 ' T ] X T I L E F I I } I T E S

Iilastic Ilccovcry

Nylon is a highly clast ic f ibre, in that i t wi l l recover i ts or iginaldinrcnsions after bcing <leformed by the appl icat ion of a strcss.Standard f i larnenl. has au clast ic recovery of 100 per cent at upto 8 per ccnt extension; high tenacity f i lamcnt has a rccovery of100 per cent at up to 4 1:er cent extension.

In this respect, nylon has a rcsenrblancc to rubber, but. i t c locsnot recovcr or snap back as quickly as rubbcr aftcr the rclcascof tension. Like rubbcr, howevcr, i t t r ies to return to i ts or iginallcngth rvhen held in a stretched condit ion, ancl unt i l a l lowed tocontract i t exerts a force Lhat resists the rcstraining inf luence.

I I nylon is stretched for several days, ancl then al lowed to relax,i f . rv i l I recover some 50 per cent of i ts strctch almost imntediately.- I 'hc

rest of the recovery takes place rnore slowly. During t l ief i rst 24 hours, nylon wi l l recover about 85 per cent of the totalstrctch, but i t may take 2 wccks to rccover complctely. Thc ratcof recovery is i rrcrcasct l by incrcasc iu tcnrpcraturc or rclat ivchunridi ty.

Lr i t ia l Modulus

I{egular f i lament: 353.2-530.0 cN/tex (40-60 g/den).

Avcrngc Stillncss

Regular f i lanrent : 159 cN/ tex ( lB g /den) .High tenacity f i larnent: 282.6 cN/tex (32S t a p l e : 9 7 . 1 c N / t e x ( l l g / d e n ) .

g/den).

Average Toughncss

R e g u l a r f i l a m c n t : 1 . 0 8 .High tcnaci ty I i lanrcnt : 0 .77.

lilcx Resislancc

E x c c l l e n t .

Abrasion Rcsis t : rnce

Excel lent .

Spcci f ic Gravi ty

1 . t 4 .

' r l\

u0 .l,t I

t | : s Y N I l r l j ' r t c r ; l l i l u i s

N y lott 6.6

Ellcct of Moislure

Ny lon absorbs on ly a sma l l amoun t o f n ro i s tL r rc co rnparcd w i thnrost natural f ibres. l t has a regain of 4*4..5 t)er ccrrt .. , ^1 'he t cnac i t y .o [ tho rough ly wc t ny lon i s i ( ] t o t0 pc r cc r r t o fI rs qr), (condltroncd) tenlci ty. Thc clongir t ion of wcI rrylon is5 to 30 per cent greater th:rn that of c lr l i (con<l i i iorrcr l ) nylorr.. The f i lanrents do r)ot swcl l appreciably in rvatci ;" t t rc di l ructcrrncreases only by about orrc_f l f t icth.

Ihermll lrropcrlics

Me lting poirtt.

Approxinratcly 250"c. -r ' l rc rrngc of rc ' lpcl . . t rrc ovcr. wrr icrr

nylorr softcrrs and rncl ts is vcrV narrow.

i l A N D n O O K O F - T E X T I L E r t l l i l l E S

II lJcct ol Low 7'erttpcratttrc

Nylon retains i ts streugth rvel l at low tenrperatures. Alter severalhours at -40'C., a nylon rope does not lose strength, and thestrength is retaincd after the rope is rccondit ioned at nornralIen']pcra tu res.' fhe

tenacity of regr.r lar and high tenacity yarus increasessl ight ly rvi th a sl ight decreasc in elongrt ion when t l rey arc chi l ledto abou t - 80 'C .

ElJect ol I'l igh TetnperatureNylon can withstanrl tcmperatures rU) to about [50'C. for manyIrours without undue loss of strength. I t turns sl ight ly yel lorva f t c r 6 hours a t 150 'C .

Prolonged exposure in air at elevated temperatures causesclcter iorat ion of nylon, as evidcnccd by permaneut losses inbreaking strength, breaking elongat ion and toughness. The f ibrecl iscolours (yel lows) [o sorne extcnt, and uncler many condit ionsof cxposurc thcre is also an increasc in the resistancc to ini t ia ls t r c t ch . :

Apart f rom t l i is ef lect oI prolonged cxposure, there is aninstantaneous and reversible change in thc f ibrc propcrt ies withincrease in ternperature, result ing in a decrease in tenacity andan increase in elongat ion.

Ant i-oxiclants are added to nylon yanls for sonre (general lyindustr ial) end-uses to conler a high clegree of heat resistance.

FlantmabilityNylon is lcss { lamrnable than cotton, rayon, wool or si lk. I f af lame is appl ied to a nylon fabric, the mater ial rnel ts and tendsto drop away. The fabric does not normal ly support conrbust ionon i ts orvn, but i ts f larnmabi l i ty may be increased by the presenceo[ certain chernical f in ishes and dyes.Ign i t i on tempera tu re : 532 'C .IIeat Cdpacily arttl IIeat of Fusiotr1- lre spccif ic heat o[ nylon at 20"C. is 0.4 calol ics / gr.a rn /

"C. At230"C. , i t i s 0 .6 ca lo r ies /g ran r / 'C .

Tlre hcat oI f rrs ion of nylon is 22 calor ies/granr.

'l' lrc rrrttrl C o ntl rtcl i vi t yl -he thc rn ra l conduc t i v i t y o f ny lon po lymcr i s 1 .7 B .T .U . /h r . /f t r . / ' F . fo r I i nch o f th i ckness .

242243

t r : s Y N r . l r E . l . t c F I n R t i s'l'lrcrtnal

Expansiort ond Cont ractiottI teshrunk nylon ya.rn <Jccrcascs sl ight ly in lcngth with an incrcascrn temperature and incrcases sl ight ly in leng*th rvi th a clccrcascln tentperature. In thc tentpcrature rangc fronr 25 to l - t0, ,C. thcclrange.in length is about o.007To p";'T (07;O;i" per.F), rvhcrrthe nroisture content of the yarn rcnrains co,nto, , i

,

S ltri nkage P ro pcrti e.rWhen nylon yarn is rentovcd fronr thc bobbirrs ant l al lowc<.| torelax with_no tension, i t nray tcnd to "ontro" i oi s irr inf by about?:9^..i: ?! per cenr, rhe icrual am";;i-;;;;Jll;,g u1,on rrreprevlous Lreatment of the yarn. This. is rclaxat ion shrinIagc.The unrelaxcd resiclual,s irr inkagc.of , ,y i ; ; ; , ; ; ; is thc nrnount lof shr inkage that takes place in boi l ing watci i rnnicAiatcly attcrthe yarn is remove<I frTl^rhc

_boby"rl n^ ivrrf""i""nluc forr,rlris _-\rcsidual shr inkage is in thc .n.ng: q to l2 pcr ccrrt , cornrno\ i ly9 to l0 pcr ccnt. ' I 'h is

f igurc i rrcrudcs t tr . r" i , i*^ i iu, , srrr i rrkngc,and i f this has been ai lowcd to tnf ."- f fnl . L"tor" pta. ingthe ya.rn. in boi l ing watcr, thc rcsi<lurr l l f r . i , i , , .g" is rcducct laccor dingly.lVlren. conrplctely prcshrunk yarn is iutnrersc<l in watcr i t rv i l lgain in. length. This gein , . , lny b" u, nrr i . . t . r u, i 'pcr ccnt. I t is Ireversible elTect and should not bc confusccl wit l i t rue shrirrkacc.

Ellcct of AgcNegl igible.

nffect 0f Sunlight

ln comtnon with most other-tcxt i lc. f ibrcs, nylorr is al tcctct l byprolonged exposure to r iqh.t . r 'hcrc is " gr, i , i ; i . i i ; ; o[ srrcngtrr ,but l i t t lc or no discolouiat iorr .I 'he degree to which nylon resists dctcr iorat ion by sunl igl t tor ul traviolet l ight in a part icular ."ng. , i * ,"" i l i lgths <l"pcrr<lsrrpon a nunrbcr of factor.s, ns fol lows a

"

. , I . Lus t rc . .B r igh t r r y lo r r i s cons i t l c rab ly n to rc r cs i s tan t to l i gh tlha r r Senr idu l l o r DLr l l .2. Anrount of surface exposecl.3. Size or diarnetcr of exposet l f i lanrcnts. I_l igh t tcrr icr perf i lanrent nylon is morc rcsistant to l icht.

i l A N D I I O O K O r T E X . T t L E l : l B I { U S

4. Length of t i rnc of exposure arrd intcnsi ty of l ight.

5. Tinrc of ycar and geographical locat ion. Nylon deter ioratesnro rc r l p id l y i n su rn rnc r .

6. Tenrperatures during exposurc.

7. Locat iorr of exposed nylon, indoors or out<loors.

Stabi l izers. n.ray be inco^rporated in nylon to give improveclresistance to l ight and heat for special iz.ed ippl icat ions.

Chcntical Propcrtics

Materials [:Iaving No Penrtatrerrt Eflcct orr Nyjlo,, ynr,,

Most conrpounds of the fol lowing gcncral typcs have l i t t lc or noef i 'cct on thc. lcnaciLy and clougat ion oi- nylon yarn rrndcrordinary condit ions of exposure:

A lcoho ls

Aldehydes

Alkal is

Dry cleaning solvents

Ethcrs

Halogenated hydrocarbons

Flydrocarbons

Kctorrcs

Soaps and synthet ic dctergen ts

Water, including seawater

Ihc rcsults of tcsts carr ied ouI otr nylon yarn, br ist lc ancl f ishingl inc are shown in thc fol lowing tabtt . fde nylon was subjectcJto trcatn)cnt as indicated in thc table, anrl strengt lr lucasurcntentsrvcrc nrade before exposure and on the washed-and clrietl santpleaftcr cxposurc. None oI thcsc t lcatn)cnts causcd a signif icant loss( lcss than 5 pcr cent) in the strcngth of thc ,u,nfr i" l .

u4

-1 r-1 --l r-[ .-I r l . ] , I

245

N : S Y N ' r . , I E T I C I : I B R E S

Materials Ilaving No pcrrnanent Etfcct on Nylorr 6,6Cltcntical Cottc,ctr- .lcttt

p. ,l.ittrc

, . ! . ' . ""nt ' , ("c ' ) ( t r . )

\p?r cc,rl )AcetoneAcetic acidBenzeneCarbon tetrachlor idcCotton scec| oi lDich lorodif l uoromethaneEthyl alcoholForrnic acidHydroxyacctic aci<lLardMethyl alcoholl )otassium carbonatcPotassiurrr hy<lroxidcSea water (Flori<Ia)Sodiurn cya ni t lcSodiunr hydroxi<.leStoddard solventTelrachlorocth ylene' l ' r ichloroethylenc

25t 0 0?525822525

1001008225) 5

65

2585252525

603

606()

120t726033

l2O -,.fo \

2 rr'rbrrl lts3

4 wcck st6 t ll ( t606060

t 9t 0

I 0t 0

Materials IIoving o pcrtnrtttetrl EfJect otr Nyltttr l,urtr

Pj"r : : | t : f aci<l ancl sulphuric acict in 5.0 pcr ccnr conccntm_l lons at room tcmpcrature causc aborrt 25 p"r. . , , t loss i rr strcrrgl l roI nyron yarn in I t* davs-.Srre.ngrh t" ; i ; , t ; ' ; : ; r r wrlh lorvcrconccnrrarions of thcse o.i.r,. 'r 'ri i 'uiJ""i'.i.i l"rrli l i '.n irrcrc'scswilh thc conccntral ion at)o tct i l l )crature.

^^.O-1ol i" acid. in 3-0 per cent colrcentrat ion at roonr rclnpcralurccauses somc detcr iorat ion of nylon vnrn. f . i r"

' "" . i " ' " f <lctcr ior:r_t ion i rrcreascs rapi<l ly wit l r tcnrpcratt i rc. nt 100;C.; about 35 pcrccl l t Ioss.of strcnglh occurs in 3 hourr.

rome dc rc r io ra r ion o f ny ron .ya rn takcs p r ' cc du r i r rg r r c r t l nc ' lrv i th blcaches o[ thc or<. l i r :<rcpc n <r.s,;p;;' ;, ;l;;,;:; ";?'1,, :l::i,]li:.ii;:'.fi "" i#:' TITU?llccnt ra t ion o f rhe b lcach ing agcr r ts , r l l " i r i i : i ' i j , " rb lcach barh,and the t inrc an<J tcmperature of.ttr" trcninr.-,rt." '-

'

I I A N D B O O K O F T E X T I L E F I N R E S

Air (oxygen) at high temperatures causes deter iorat ion ofnylon (see Thcrnral Propert ies).

Solv t rr ts lor Nylotr

I . Concentrated formic acid at room temperature (27'C.).

f lhe solubi l i ty fal ls off rapidly as the concentrat ion of formicacid is d ecreased.)

2. Phenol ic compounds such as phenol, cresols, xylel lols andchlor inated pl ' renols (27' C.).

3. Calcium chlor idc i rr methanol (saturated solut ion at 27'C.).

4. Concentrated ni tr ic acid, concentrated sulphuric rcid anclconcentrated hydrochlor ic acid. These agents appecr to dissolvethe f ibre but in fact break down the molecular structure of thepolylner.

5. Hot solut ions of calcium chlor ic le in (a) glacial acet ic acicl ,(b) eihylene chlorohydrin, and (c) ethylene glycol.

6. FIot solut ions of z inc chlor ide i rr methanol.

7. Benzyl alcohol at thc boi l .

S wel l ing Agctrts lor Nylon

The fol lorving agents cause an appreciable increase indiameter of nylorr f i lanrents. The el lect of these agents onstrength of the yarn was not determined.

thethe

Chett t ical

Acet ic acid

Adipic acidAn i l ineBenzene sulphonic acidBenzoic acidDoric acidChloral hydrateChloroacet ic acidFormic acidC lycolLact ic acid

Cortcettl raliott(per cent)

1 0 0

2Saturated

20SaturatedSaturatcd

202020

100t00

L.l0

Solvcn! orDilue nt

lvlethanolM ethanolWaterWaterWaterlvl cthirnolWalerWater*uY

n : s Y N T l t F . ' r l ( : F I I R E S

Cltenticol

Li thium bromidei\,letacresol

p. Hydroxybenzoic acidPhenolI)hosphoric acid

Zinc chlor ide

P ers piratiort

Concenlratiott

{ptr ccn t)

Concentrated22

20

2020

Sltura(ed

Solt,ctrt ttrDi luctr tMct ha nolMc thano lWu tcrM etha nolWatcrMc th rno l i " '

WaterWater

Exposure to synthct ic perspirat ion, both acid and nlkal inc, hlsl i t t le ef lect on the tenacity of nylon. Af. t er Z hours at 100"C..exposure to an acid perspirat ion solut ion rcsulted in only an8 per cent loss in tensi lc strcngth. Unrlcr lcss scvcrc conrl i l iotrsof ovcrnight cxposulc at roont tctnpcraturc thcrc is rro loss of lstrengt lr .

Acid.s

Di lute acids have l i t t lc e(Tcct on nylon un<ler thc con<l i t ionse.ncountered in pract ical use. Hot nt incral acids wi l l , howcvcr,decompose nylon. Thc f ibres disintegratc in boi l ing hyclrochlor icacid.of 5 per cent strength, and in cold conccntratccl hyt l rochlor ic,sulphuric arrd ni tr ic acids.

Alkalis

Nylon 6.6 has excel lent resistance to alkal is. l t can bc boi lcd instrong caust ic soda solut ions without damirge.

Ellcct of Orgnnic Solvcnts

Concentrated fornt ic acid, phcnol an<l crcsol are solvents fornylon. The f ibre is not attackecl by solvcnts usccl in <lry-clcnnirrg.

Insccls

Nylon cannot scrve as food for ntoths or bccl lcs.

Micro-organisnrs

Nylon is not weakcncd by nroulds or bactcr ia.

247

1 ,000 cyc les ; l 8 pe r cen t r .h . ;I ,000 cycles; rvet; 22.C.

60 cyc les ; d ry ; 33 .C .60 cyc les ; d ry ; 90 "C .

T i A N D B O O K O F T E X T I L E I - I B R E S

lilcc(rical I'ropcr(ics

l 'hc low nroisture absorpt ion of nylon encouragcs the accunrula_t ion of stat ic electr ic i ty, but the efects nray be overconre by useof ant istat ic f i t r ishcs and stat ic cl inr inator i .

Volutne Resist iv i ty:

4 x l 0 r { oh rns .c rn . a t l 8 pc r ccn t r .h .5 x 101 ohnrs-cnl. , wet.

IJ rca kd own st re ttgt lt :F i l n r , un ro l l cc l , 9 n r i l s . ; 1 ,300 v . i m i l .Fihn, rol lcd, 2 rni ls. ; 3,000 v./ni l .

Dielectric Properties

I } : S Y N T I I E T T C F I I ] R E S

(c) l lxcel lcnt rccovcry from dcforrnlr t ion.(d) High abrasion rcsista ncc.(e) High flex resista ncc.

. ,-- fhe tenacity of nylon rnay bc adjustcd to providc for nrost of

iitX#?:I:il'*i,:f ,fll"" appricaiio;;; i*ri'aj''e r' i gr, i." ".iiv

1'l:c rrigrr clo'gatio' o[ rcgrra_r 'yro., lrss.ci.tccr witrr itscxcellc'r. crasriciry, makes nylo' rhc i ircal 'f itr,."

i;;;r,;, l i i i ,r" ' i3ii'lr"lli;,lX,ltlas

ladics' hose' which *i r r "e"i" t I'"i' ffi ;"';i;;;Some itenrs ma<.le frorn nylon have shown phcnonrcna[ atrrasionresistance in use. This property is relatetl to itr.

'in t,.r"n t lough_ness of the f ibrc in tcrmi of resistancc i"

'n.*i"g, i ts rraturalpl iab.i l i ty and jts recovcry tronr. Acfoi,rr,";"". U.. i",,re o[ nylon,stoughness and rccovcrv

-aft"r ,r"foniir;;;";,, il- rcsisrlrrcc iscxccllcnt.

,,^l l"^ T.:.h"l l ical propcrt ics of nylon arc nl lcctcct orrly ro a low:":.1:".

ot moisturc, and fabrics i .nlnin ,trui ig irrrt l sr:rt>lc wtrcnfhe high strcngth, associatccl with lorv spccit ic graviry, givcnylon a high strengrh to weight.ratio. i fr" i"*,.p."l t ic gravity sug-gests that yarns should tc rrurty , ino et" irr; i ;"r ' covcragc tharrmany other f ibres. but this is o0.sct to somc dclrcc by thc nurrncri' which the snrooth, ,"s,,roi ro;,,j fi;il;,:';;" abrc ro pack

,Tg.]lt:t inro com-pact yoin...i.h. "fr";i ;l;i;;; is wcrr ilusrrarctJoy cor:rparison of nylon wilh si lk. nf tf ,oi,gi l io' i f"<t-oft si lk hasa specif ic gravirv of r.25, nyron (spccif ic erf i i ,y l . ' iql rrosc oI trrcsanre.,weight and gaugc are much nror" sl| '5"..,-,

' ' 'Arrnough nyton hls a high breaking tenacity, i ts init ir l nroclulusis relatively low. ' I .his

nrcans_lhat i t is part icul irr. ly scnsit ivc tostrctching under low loads. .. fhc for". i i", f"oi" i lr . srr"rs-stroincurv-e rises less steeply tlran thc ,,ri,lAf. lr*iil,i an<t irr this lowerrcgron n srrral l chanqc of lo:rrI procluces consijcrablc clorrgation.-l 'his

lower cn<l of t l ic crrro' t"r'sions-iii ;;';i; ;;i::l;11'":"^rs

tltc gorrcrrtl workirrg *rcnro csrabrisri i;J;;;"'.:'i:f il';1,1,li,l, ;l:i illlil,fi ",iff],:tevenly as possible.

Thc history of the varn, being uscd has a considcrnblc i , f lucnceon irs sensiriviry ro sircrcrring. j;;;;;;; i, ' .; ' i i i"-i",.", (sucn ashcat rclaxing) which incrcls", Jtn,,gnti.ri i,,,, ir-c,"' incr""s"s i l,.

K'r' 24g

Power Factor(pcr ccn t)

22 'C. 5 .0I t . 0r . 8

I 3 .0

DielectricConstunl

4.020.03 . 87.O

to the sk in .

have enabled i tsyn the l i c tex t i l e

i n c l u d e :

Allcrgcnic IrropcrticsNylon is chernical ly i rrert ancl wi l l not cause irr i tat ion

Ilcfracliyc IndcxIn ax ia l d i rec t ion : 1 .54?Itr t r tnsvcl 'sc direct ion: 1,521

NYI,ON 6.6 IN USE

Gcneral CharactcristicsNylon f ibres offer a range of propert ies whichto beconrc one of the nrost successful of al lfi blcs.

Mccltanical P ro pc rt icsThe outstanding mcchanical propcrt ics of nylon

(a) I- l igh strcngth-to-wc igh t ral io.(b) I- I igh brcaking clongarion.

248

aj-L--t .-t --I -l r-T -I -r ' I - r - - r - r - . a f 1 ' . - - t

t F : - - - - - - - F .I I A N D I } O O K O F T E X T I L E F I B I T E S

tendcncy to stretch under low loads. By the same token, nornraltcnacity yarn stretches more easi ly than high tenacity yarn.

Humidity is also a factor which inf luences nylon's resistanccto stretching. In otre ser ies of tests, for exanrple, wet nylonstretched I per cent with only 24.2 per cent of the load requiredto stretch bone dry yarn I per cent. Nylon condit ioned at 50 perccnt r .h. required 64.6 per ccnt of the load needcd at 0 per centr. h.

I-l cat SettingNylon f ibre, yarn or fabr ic may be heat set readi ly in ei therdry hcat or steam. The threshold temperature for dry heat isin the region of 205"C., btr t rnuch lowcr temperatures wi l l br ingabout heat sett ing in the presence of water, e.g. in the region of120'c.

Goods which have been hcat set by ei ther the dry or wet

lrrocess rvi l l subsccluent ly hold thcir gconlctr ical couf igt trat iotrthrough processing in boi l ing water, i rud wi l l exhibi t wrinklerecovery character ist ics conrnlensurate with t l te severi ty of thcsc t t i ng opc ra t ion .

Fibre rvhich is beat set under dry condit ions su{fers a com-pacting of the internal structure, which results in decreased dyereceptivity or dye rate. Fibre heat set under wet conditions resultsin a more open structure, wl'rich dyes deeper.

These properties impartecl to nylon by heat setting have beena nrajor factor in i ts acceptance iu nrany consumer uses. l t isfortunate thrt nylon 6.6 heat sets rcadi ly at temperatures in thcrange of 205"C., which is wel l below i ts melt ing point of about250"C. This al lows a good operat ing margin in heat sett ing, hotdrawing, calcndering, pleat ing and yarn textur ing operat ions.

Te.rt nri ng

The thernroplast ic nature of nylon has made possible thesucccssful dcvelopnrent of a wide variety of permanent butkingand textured cl fects ou cont inuous l l l i rment yarn. I r{any processesaro userl , rvhich arc basccl gcrreral ly on trvist ing, cr i rnping, loopingor cur l ing (dcfornt ing) rvi th sonrc sort oI hcir t sctt ing. ln adt l i t ionto providing addit ionel bulk and texture to the f i lamcnt yarn,these proccsses nray or may not intpart a certaitl deglee of stt'etchancl recoverabi l i ty.

The text i le industry has nt ldc good use of this aspect of nylort

250 251

. S Y N T I I E , T I C F I I T R E S

processing, by developing an cxtensive varicty of cncl t tses,part icular ly in kni t art ic lcs and garmcrrts. I lxanrplcs includc r l {nrswomen's and chi ldrcn's hosc, bathing suits, undcnvcrr, glovcs,sweaters and dressrvcar.

In addit ion to the propert ics of lof t i r rcss und strctcl t , l l tcscyarns and thc fabrics nradc fronr thcnr nrc charlctcr izct l by goot lcover, l ight weight, soft l rand, dul lncss, incrcasct l : r t rsorpt ion,durabit i ty lnd frecdonr from pi l l ing. E,:rch oI thc prt tccsscs iscapable of producing rnodi l ic l t ions of thc bulkcd yarn by chltrg-ing the basic character ist ics, providing f lcxibi l i ty and adaptubi l i tyto different end use requirerncnts.

I{ cut Rcsistancc

Nylon 6.6 has adequatc rcsist lncc to hcat for pract ical ly t l lapparel and honte furnishing uses. n nt i -oxidlnts arc lc ldcr l to sorrrcya rns to con fc r r h ig l r dcg ree o f hca t - r cs i s taucc fo r so r r rc i r r t l r r s l r i ; r lu ses .Flantc Resistarrce' l 'hc

f lanrrnabi l i ty of thc f ibrc i lscl f is only onc lspcct of l l :urrrrrr-bi l i ty of the labr ic coustructcd fronr i t . Othcr factors arc involvcr l ,including construct ion, type of sur lace (brushcd or nirppcd, forexanrple, as comparcd with clean), the typcs of dycs nnd chcnricalsused in f in ishing, and the moisture contcnt of thc nratcr ial .

Clcan, undyed fabrics of nylon hrvc a goo<l lcsistencc loburning ancl are considcred highly sat isfactory for pract ic:r l ly nl llext i le purposcs. Whcn nylon nrel ts, i t forms a nrcl t bal l whichdrips away. Usual ly, wherr thc igni t ing f lnnrc is rcrnovcd, thcf larne cxt inguishes i tsel f . Dycd and f inis lred nylon, howcvcr, wi l lin some cases support the spread of f larne. In pr inciplc, anythingthat wi l l tend to hold the structure togethcr and rct l rc l orprevent dr ipping of the molten polynrer wi l l help to supportthe spread of J lamc. Iror this rcasorr, prcmctl l l izcd arrd chronrcdyes, thcrmosctt ing rcsins and certnin f lanrcproo[ irrg conrposi-t ions developed for other f ibres nray tcnd to incrcirsc thc cnpacityof nylon fabrics to support lhe sprea<l o[ f lurnc.

lv[ oist u re- fhe

r : r te w i th r vh ich ny lon co r r rcs to cq t r i l i b r i t r r r r r v i th l hc s r r r -rounc l i ng a i r dcpends upon thc avn i lab lc su r f i r cc ; r s r vc l l us t l c r t s i l ylund typc o[ packing. For this rcason, the only sl fc corrr l i t iorr i rrg

i i

i

I I A N D B O O K O F ' I ' E X T I L E F I B R E S

lrextnrent should be control lcd by dai ly weighings unt i I constatr twcight is rcached. A shcer fabr ic wi l l come to equi l ibr iurn in lessthan an hour i f loosely draped over a rack. The same fabric whentight ly rol led may take l0 days. Shipping bobbins and warpssonrct inrcs require 20 days or ntore.

Static

1'he rclat ively lorv rnoisture absorpt ion of nylon is conducive tothe accumulat ion of stat ic elcctr ic i ty. This nray cause a problemin nylon processing, encouraging bal looning in yarns and theinabi l i ty to lay nylon [abric straight on tables and trucks. Stat icnray also cause a yarrr or fabr ic to pick up soi l ing mater ials. I t isnccessary i rr the processing o[ yarns and frbr ics, therefore, toensure that stat ic is kept to a minintutn.

Stat ic nray be control led by modif icat ion of the polymer andthe use of ant istat ic agents. A high humidity in processing wi l la lso prcvcnt the accunrulat ion of stat ic clcctr ic i ty. I f hunt i t l i tyis too high (above 75 per cent, i t may lnake the f inish tacky andcreate tension di f i icul t ies. I { igh humidity I nray also produceuneven stretch and recovery due to the tendency of the nylonto stretch nrore easily as the humidity increases.

Static eliminators are very eflicient when positioned efectively.In warping for tr icot, for exanrple, the el iminators should beplaced at each drop wire bank on the creel just after the eyeboard and as the ya.rn goes on the beam or spool.

Nylon should always be al lowed to condit ion for at least 24hours open to the atmosphere in rvhich i t is to be proccssed.

Ligltt

Most f ibres undergo degraclat ion when expose<l to l ight, result ingin loss of strcngth and other piopert ies. The relat ive mcri ts offibres in respect of light resistance can be assessed only againstident ical concurrent cxl)osures, and some data comparing nylonwith other f ibrcs is given in thi fol lowing table.

The rcsults of this tcst incl icatc that nylon rates below thcf luorocarbon yarn and acryl ic f ibrc both in the open and underglass. Behind glass, the polyester is second only to the f luoro-carbon yarn. Sonrc inrprovement occurs in nylon durabi l i ty byplacing i t bchind glass.

' fhe wavelcngths that degrade nylon rangc fronr 3,200

252

r . t - r r r

B : S Y N T I . I E T I C F I D R E S

Fibre Dcgradatlon lry Llght

I:ibre A vcragc Percentage Sicn'tt{tIlctuirred

Ouldoors Dchind G lus.s

Fluorocarbon yarn ( ,Tcf lon' ' l 'FE)Acryl ic f ibrc ( 'Orlon,)Nylorr yarn (br ight; 6.7 dtexl f)Polycster (br ighr, semidul l , dt i i l )

('Dacron')High tenacity rnyon

1006 l50

7223

r005738

l 68

orlu?1r";,"l"",inuous cxposure, Miami, Florictr; fncing sourh at

Angstrdnrs into thc vis iblc l : luc sl ight ly abovc 4,0f i ) Angsrr i jms.l"or thjs reason, thc cflcct is lcss pronouncecl oii-nyto,l thrtr onthe polycstcr wlrcn the two f ibrcs nr" pln." , l unlcf glr ,ss.

, ,_I l lo, l i th, durabi l i ty of nylon is extendcct t y "" i tain prcrrrctal_

l tzeo 0ves-

Washing

Colour.ed nylon goods are best washecl in warru water at 50oC.,

*1.y"T11 ilt_1lj:g{r.r, 6.0"C. Blcntrs of nylon and couon nrlyDe wasllcd at. rathcr higher tcnrperat.ures, up to about 70.C. WhitLand l ighrcoloured fabrics nray pick uf t ints ir lnr colourc<lfabrics, and the two shoulct be *ortr.. l . .pn,ntlv. -

Bleaching is genepaIy unsatisfactory, "",r ,r i". ir,r bc avoidcd.

Drying

Nylon fabrics absorb very.l i t t lc water, and thcy dry quickly. Dripdrying or cokl tunrble clrying arc prcfcrrcd. ' J I

Ironing

I]]" i- l i . ,"T:"l lerrr qualir ies of crcasc rcsistancc an<l shapc rctcn_ron, especraily whcn it has bcen ellectivcly hci l t sct. A nrininrurnanrount of ironing _is requircd; this nrly bc clr i iccl otrt wirh aory lron at 'synthctic' sclt ing, or by using a stcanl iron or srcarn

251

I

I I A N D B O O K O F T E X ' T I L E F T B R E S

press. Ironing tenrperatures above about 150'C. should beavoided. Glazing may occur at higher tcmperatures, and st ickingrnay occur betrveen 205 and 240'C. Excessive exposure to i roningtenrperatures n'lay causc yellowing.

Previous trcatr i lent of thc fabric has ir cousiderable el lect onits react ion to pressing condit ions. Certain dyes may changecolour at elevated temperatures. I f a cl-range of form is desired,e.g. in creascs, plcats or wrinkles, the condit ions of ternperatureand rnoisturc under which thc fornr was establ ished must beexieeded to produce a perrnanent change.

Dry Cleaning

Nylon is not af lectcd by any of the solvcnts commonly used indry cleaning, and there are no di f l icul t ies involved.

End-Uscs

I! onre Furnislr ings-fhe

rrajor uses of nylon in this f ie ld are in carpets and upholstcry.

Carpets

It is apparent that several of the character ist ics of nylon areof value. in carpets. Among these are appearance retent ion, whichis a funct ion of abrasion resistance, texture retent ion, recoveryfrom crushing, durabit i ty and dye fastness.

A nrajor proport ion of al l carpets and rugs is now rnacle orrtuf t ing nrachines, and three general types of nylon yarns are used:

( l ) Fr ieze and Nubby.(2) Velvet.(3) BCF (Bulked Continuous Fi lanrent).

Al l these three types depend upon heat sett ing to providcthcir nraxinrunr funct ion in carpets.

Fr iczc Yarn. In i ts rel ' , rxcd, kinked forrn, a fr iezc yarn looksas though i t would not prss through a tuft ing ncedle. l lut thelorv forces nceded to elongate nylon ( low irr i t ia l modulus) areadvantagcous in this rcspect, as the yarn appears unkinkcd whenwound on concs. When unwouncl. the nvlon does not recovcr

254

I. , . i .

N : . S Y N T I I E T I C F I B R E S

ins-ta n 1nn.o ur lr ' , and adequatc l ime is thus providccr i rr tuf t ingbc[orc the yarn asserts i ts elast ic recovcry.

, Vclvet ' I 'ype Yartrs. l 'hcsc lencl to clongntc on thc packirgc,but 'b loonr '

whcn convcrted into carpct pTt. -

BCF Yarns. These arc bulky in carpcts, but cornpact whi lcon,the.shipping package. They pass readi iy rhrougri th" cr"" iand tuft ing machine, dcvcloping subscqucir t ly thc nraxinturrrbulk and covcr in thc carpet. where tcnsiorx arc rro longcrpresent.

. . .11 , t : . ] f :11^nt. ,properry of. al l rhree types of hcar-sct nylonya.r ls l : , rnetr abl l l ty to pass through piccc_dycing operat ions anrlretaln rnelr appearancc and physicaI cha ractcr ist ic i .BCF yarns. have gained wide acccptancc bccause of thcecononly provided by this type of yarn in cornparisorr with sprrnyarns; many handl i rrg and proccssirrg opcral iorrs arc nvoit lcd

I!1"- : l i l l . l lo"iding a yarn foi carpcrs *itf i .*..f i. i i i pcrforrnuncccnaraclenst lcs ln tcnns of tuf t ing cl l ic icncy, piccc clycabi l i ty,bulk, covcr, wc:rr , styl ing rrnd apl icararrc" ," i " , , i iu, i .

-uy attcnng i l rc cnd_groups balancc irnd thc physicul prol)crt ics:{ .nYfol

yarn, i ts dyc rate ancl dye capacity cai bc controi lcr l .This technique is used in producing t . i -Ay. ' . t t . " t . which br inginrprovcd styl ing of both

-BCF onJ .pun'V"r, i r . ' i l r i , pr inciplc

is used. in carpets, upholstery ancl appaiel .,i<'1 ,,r.r.-,

Furthcr sly l ing ef lects in carpcfs in<J upholstcry arc achicvct l

i l " . : , lo2l$. yrnrs.of rn ixcd count , g.C. 20, t7 ant t t6.7 t t tcx/ t .( ro , r J , o oen i t l w t i l l i l l ec ros {yeab le ya - rns and inc lu t l i ng th recplies and two twist levels along wiih two if if Li. i, i '*. igt, t levcls. l lyconrbirring lhese factors, as riany as fS0,00ij sivlc conrbinatiorrs

arc obtainable, excluding colour ancl pnttcrn.

. Adding to rhis rhc possibi l i t ics obt i incct by using rhc di f lcrcnr

s rap le . and l i l an ten t p roduc ts , thc nunrbc r o f conrb ina ( io r rsex(ends into the nt i l l ions for tuf ted carDcts.

_,fh. , ul" of space .clycing, spacc icsist t rct tnlcnts pr ior lo

l1c-cc. dycrns, yarn dycing and pr int ing introduccs othcr possibi l i -

t rcs lor stylng in thc ci l rpct f ic ld.

U plrclstery

Nylon's combinat ion of strength, dyeabi l i ty, rbrasion rcsistrncc,high l ight fastness and lustrJ ( .Antron') i iavc olxnccl up a,r

255


important nrarket in the upholstery f ic ld. Nylon provides fabricsrvhich conrbinc bcauty, perforrnance and pract icabi l i ty.

Apparcl

The fol lorving cha racter ist ics, among ot l rers, are important infabrics to be used in rvearing apparel:

( l ) Protcct ion - Cover, warmth(2) Aesthet ic appeal - Texture, colour, hand, drapc(3) Ease of care(4) Durabi l i ty - Abrasion resistance and strength(5) Appearance retent ion - Wrinklc recovery and soi l rcsistancc(6) Comfort - Wcight, openness, tact i lc propcrty.

Many of these character ist ics are inf luenced great ly by theyarn size, denier per fihnrent, lustre, fibre cross-section, fabricconstruct ion and weight. But within the franrework of yarnand fabric construct iou, sonre f ibres pcrfornt better than others,and irr this respect nylon contpetes most ellectively.

Nylon lends i tsel f to ntost types of fabr ic corrstruct iorr , inclucl-ing the fol lowing types which are inrportunt in thc apparcl f ie lct :

Surah, tr icot (plain and brushed), s inrplex, I in ings, hosiery(circular and fully-fashioned), tafl'eta, crepe, satin, reinforcedtwi l l and sateen cotton, ski-wcar fabr ic, velvet f leece, brocade,matlasse, circular kni t s ingle, c ircular kni t double, ful l fashionknit , tape and r ibbon, lace, shcer, organza and seersuckcr.'['hese

fabrics arc used for all nranner of apparel end-uses,incl trding thc fol lorving:

Lingerie, swinrrvear, ladies' outerwear, nren's ourcrwear,stretch sportswcar, hunt ing apparel, urr i forrns, hosiery, swcaters,dresses, (kni t) , skir ts (kni t) , socks, gloves.

The introduct ion of textured yarrrs o[ nylon in recenr yearshas opcned up a vast nerv f ie ld of appl icat ion in the product ionof garments that perforrn because of c i thcr bulk with low weightor bulk with clast ic recovery for bettcr f i t . In addit ion, specialconstruct ions such ns boucl i c[ Iects arc obtainirble anrl di l lcrenttact i lc l r ropert ies are providcd.

fl o.ricry

Nylon ruadc an irnnrct l iatc nppcal as a hosicry f ibrc, an<l f rornthe day of i ts appcnrance on lhc lnarkct i t bcgarr to oust si lk

T r l r I r [ ' I

256

-!

B : , S Y N T I I E T r C F T D R E Sfroln i ts donrinant nosit iorr in thc qual i ty hosicry f ic l<J. Onccprc-boa.ding was adopted, therc wcre,r" i " i r pr"Lr."rs associatcdwith the use of nylon in ta<tics, l;;rt"d. tJil; or thc fabricconfiguration was essential to p.crmit passag" "f ifi. hosc throughthc dyebath withour the formaiion of ."u"i i *r1,,[ i ls. tn acldit ion,the. boarding operarion strapes the lr"r" a;; ;;.;i;;lte <tinrcnsionand imparts clastic memory and recovery io-ii,.

'fufrri.. -I.his

isparticularly inrportant to tie appearan"J J lor,'"'in u...Post boarding was irrtroduccj nt o foi., , i , , ; ;-Thc dcveloprnent of nylon stretch yains' i i , fotto*",t by urapid increase in the use of nylon i" ;;,rlr;;;. Thc acccpranceof thcse yarns r.csulred rro'n .o,rriori; ;;;;r;,,." rcrcnrion,c las t ic i ty and cxcc l lcn t durab i l i tv .Cotton hose have bctter -wash fastness than nylon, but thcfibri l lat ion characrcrist ics "t "" i t ."- 'J",1"; ' ; ; ; causc it robecome whitene<l aftcr a . fcw repea tcJ-

-f.,in.," -i.un,r.y cyclcs.Nylon, by contrast, rvi l l wit lrstanrl. '*p."t., i" i .r. j .r ing for urrylorrg periods wirhout undergoing a"t. i i" i .1i" ir ' in' i i , npp..rnn"..The excellcnt abrasion ,"iirtni"" "a t"r; ;,;;; ot nylon nrakeIhcnt nruclr less susccptiblc to t otc io,.,rl-n't-iun",,,if

"*""r.

LingcrieTricot is onc of the nrost. important of thc warp knit fabrics,and nylon tricot has macle imprcssi". ri*J*"y

-iri rcccnt ycars.Nylon's acceptance in this usc l. ,"J"rfrrci l fV relntctl to i(scasy care propcrt ics, such as_quick drying and

" alaptabil i ty toautomatic home laundering. Equally i"1p"?t",, i in the dcvelop_

T:l l " l nylon tr icor, howevcr, was rhc abil iry of I ingcric pro-

ly::rr jo stytc day wear fabrics which are l igirt in wcight rvirha(lcqtlale 'sce throuqh covcr', attd ,| . ,""a"r ' . i . . f "car fabricsrequiring less cover. Thcsc ractois-wcr.- "i f ,rl*i.trrcc in thcdevelopment of nylon rr icot t"roi" t t ; ; ; ;";";;pcrrics wcrcrccognized.For optinrum shrinkapc control and wrinkle rccovcry, i t isessential to heat-sct nylo'n tricot. -nii, -"r,,

y 'ir.'Olir"

nr on. nr.other..of two sragcs during thc pro,tu"iioi, oi iii"' rnrrri". .n.rtwo dilTcrcnt proccsscs arc now rccognizccl. .l.hcy ar.c rcfcrrctl

l"__b-l:ldlV as (a) rhc singlc-pass proccss, an<l (b) rhc <Joublc-passprocess.In.thc sirrglc-pass proccss, t lrc _fabric is scourecl, <lycrl, ctr icrlan<l hcar-scr, whcrcai in thc doubie-n^.,

' , ; ; ; ;";t is scourctl.

257

I I A N D N O O K O F T E X T I L C F I I I R E S

<lr icd and heat-set, fol lorved by clycing and drying. In the single-pass process, thc scveri ty of heat-set i ing is restr icted by fabricdiscolourat ion, dinrensional stabi l i ty and smooth appearance aftcrlaundering. In the two-stage process, a r lore contplete degree oIhcat-sett ing is achieved, which actual ly ycl lows lhe fabric anclnecessitates subsequent bleaching, but provides excel lent dinten-sional stabi l i ty and smooth appcarance after launder. ing.

Using tlre AATCC Wash and Wear Pcrformance scale, af lbr ic f in ished by tho single-pass process rated 2.5, whereas fabricproduced by the two-pass proccss rated 3.5. There was lcssrclaxat ion slrr inkage in the second fabric.

The wrinkle recovery propert ies of propcrly prepared nylontr icot are excel lent. This is due in part to the mobi l i ty of thcknit structure, but also to a great degree to the excel lent workrccovery of the fibre. Nylon has a high work rccovery undcrconcl i t ions of high deformation, rvhereas polyester yarns havesuperior work recovery under condit ions o[ low dclormation.

In tr icot fabr ic. the mobi le structure works to the advantagcof the f ibrc having the best rccovcry propert ies utrder concl i t iorrsof high dcfornrat ion, and trylon is cxccl lcnt in this rcspcct.

G loves

Nylon has been used successful ly in ladies'gloves made lromsueded simplex fabrics. A leather graiu appearal lce may beobtained by embossing a'crush'- l ike pattern on to simplex. Thepattern is durable to hand laundering.

O ulervear

Nylon taf leta is used in shel l c loth in jackets and wind-breakers. These garments are general ly l ined with f leeced nylonfabrics or f iberf i l l , or are laminated to other mater ials. The colourfastrress of these garments is acceptable, and they have excellentappearance retent ion and easy care propert ies.

Nylon taffcta and tr icot have founcl at l i r lportant out let inblouscs and drcsscs, whcrc thc satnc cott lbinat ion of propcrt ics

is advantagcous,

Stoplc

Nylon staplc is widcly uscd as a conlponcnt of blcncls rvi th

other f ibres, notably of cotton. A lr igh strength, high ntodtt l t ts

258 259

F F F t t F I I t F, F F F F l'iFn : s Y N T n E l t C F t r l R F . S

type f ibre wil l corrvey signif icantly highcr ylrrr arrd fabric strcnctlrrvhen blended with cotton, than can be obtt incd with yarn nrrt lfabric nrade front 100 per cent cotton. Such blcncls are cornntorrlynrade rv , i th l5 to 50 per cent o f ny lon in the b lcnd. As thc pcrccr i -tage ol nylon. increases, fabric f lcx l i fc, tearing nncl bicnkingstrer-rgth and abrasion resistance incrcascs irr suclr a rvay t lrat ab lend conta in ing 50 per ccnt ny lon s tap lc w i th carc lcc l co i tor r rv i l lhave a 30 per cent greater fabric breaking strerrgth. ' l 'hcrc rvi l l l lsobe a threefold inrprovenrcnt irr abrasion resistarrcc ancl a sixlbldincrease in f lex l i fe as cornparecl with a fabric of 100 pcr ccrrtc o t t o n .

Nylon staples of this type are uscd to rciuforce cotton fabricssuch as twil ls, sateens, denims, whipcords, dri l ls nnd t lucks. ' l 'hc

fol lowing table i l lustrntcs typical inrlrrovcmcnts in str.cngth irrrr labrasion resistance whcn 25 per cent nylon st:rple is adttct l in t lrcr.varp o nly.

Effect of Nylou Strple on Fabr.ic l)ropcrt ics

Ir ubric Property

Fabric weight (g/nr: )l l reaking strength (kg)Stol l abrasion (cycles

to destruct ion)Accelerated abrasion

(min. to destruct ion)

I'will.r

100"/, 75'/., cotto,t Icoltort 25 "/" nylort

19(trp257.6 264.44 B . l 5 4 . 5

260 1100

I )c t t i t r t s

100'/" 75' jL cottotr Icctttort 25 "/,, rtylott

tvorp381 .4 381 .4

18 84 .4

1600 4000

3 650z7

In the latent cure typc f inished fabric, nylon is uscd to inrprrtstrength and wear l i fe, The nylon component conrmonly anlountsto some 15 pcr cent.

l l lcnds with cotton contaiDing high pcrccntagcs (c.g. 50 pcrccrt t) of nylon havc grcat rcsistnncc [o wcur, abr irs iorr and l lcxI i fe, and good rcsistancc to thcrnral rat l i l r t iotr .

I rrtl usl rial' fhe

high strcngth, elast ic i ty, abrasioncharacter ist ics of nylon have opcncd up n

rcsistancc nnrl olhcrrvidc f ie ld of appl ica-

' I A N D B O O K O F T E X T I L E F I B R E S

t ion in industr ial fabr ics. Thc fol lowing are a few of the nroreir .uporta nt industr ial cnd-uses :

Air spr ings, belt ing, f i l ter fabr ics, f ish net, twine, hose, washnets, press covers, ironer covers, paddings, parachutes, webbing,sewing thread, cordage coated fabrics, bocly armour or bal l ist iccloth, tents, aer ial targets, screening, fc l ts, reinforced plast ics,ropes, blend paper, papermakers' felts, tyres, nolr-woven fabrics,back gray fa bric.

7'yrc CordThe high strength and abrasion resistance of nylon 6.6, coupledwith other propert ics such as resistance to nroisture and hcat,good fat igue rcsistance and high work of rupture, enabled nylonto nrake rapid headway in the tyre cord ntarket.

Convcyor Belting' [ 'hc

trsc of nylon as rci t t forcentcnt i rr hcavy-t l t r ty convcyor bcl t-ing is rapidly gainirrg grouncl. Nylon of iers the fol lowing advan-tages in this appl icat ion:

( l ) High tensi le strcngth.

(2) I{ igh impact strength and resistance to shock r l raintainedover long periods

(3) Good adhesion to rubber.

(4) Resistance to rott ing.

(5) Excellent flex and fatigue resistance.

(6) Low specif ic gravi ty cotnpared with natural f ibres uscdfor rubbcr rein forceutent.

II ose

Nylon is widely used in many types of indust l ia l hoscs. I t of lersa high strength-weight factor, good wet strength retcntion,excel lent f lex l i fe and loop-strcngth rat io. Nylon-rcinforccd hoscis made wit l r kni t ters, vcrt ical and horizontal brnidcrs, Wardwel l

braidcrs, Chernak loonts; nyton is also used in nrandrel-bui l twrappcd hosc.

260

t' l ' 1 ' [ ' I ' L ' I L - I r - [m ru

D : S Y N T T { E T I C F t I } R E S

(2)

Nylon 6 f ibre is sprrn fromby the self-con dcnsa t ion ofcaprolactarn:

NYT.ON 6

polycaproamidc, a polyanric lc nradc6-anrino-caproic acid or i ts lactanl,

cx. (cH.). co NHt l

CAPROLACTAM

--ruu (cx,)" co Nrr (crrr)rcor. l t (or.)r---

N Y L O N 6

TYPES OF NYLON 6 FIDI{E

Nylon 6. is pro<tucccl as rnult i f i lanrcnt yl t rns, nrorrol i la ntcn ts,staple. and tow, in a wide range of counti i",, i 'r iopf. f. i igif i i" i"suit virtually all texti le rcqurrcntenls.The f ibres are availablc in bright, scnri_<lLrl l and dull lustrcs,and with special addit ives such as optical blcachcs for spccial izcd

cnd-uscs.Li l ic.nylon 6.6 f ibrcs, thc f ibrcs of rrylon 6 nray bc vnricd in

;xopcrl ics .ou.r- 1 rarrge which is l inri tcd by thc inhcrcntcnaractenstlcs of thc polymer, each nranufacturci control l ing hisproccss to producc fibres. thht will nrect spccific rcquircnrcnts.In general, commercial ,nylon 6 f ibrcs fal l into trvo

-rnain classcs,(4, regular tenacity and (b) high tcnacity.

261

Modilied liibrcs

As in thc case of nylon 6.6, nylon 6 f tbres arc conrmotr ly produccd

in round cross-sect ion, but f ibres of special (e 'g. nrtr l t i lobal) cross-

sect ion are now avai lable from several nra nu fact t t rers.

P I {ODUCTJON

(l) Cyclolrcxattone Routc

This is thc route by which caprolactanl is comnrot l ly producccl

Rcxclant Synthcsis

Thc caprolactanr trsccl i r r l r roducit tg nylon 6 polytncr is made

by one of several rort tcs, of which thc fol lowing are important:

T I A N D I } O O K O F T E X T I L E T I B R E S

Nylon 6 is a thermoplast ic f ibre, and lends i tsel f wel l to physical

mocl i f icat ions which are associated with this property. Crimped

and textured yarns of the fanri l iar types are avai lablc.

for nylon 6 manufacture (sec pagc 263).Cyclohexanone may be made from bcnzene via

routcs, including the fol lowing :

(a) Benzene is chlor inated to chlorobenzene ( l ) , which is then

converted to phenol (2). Phenol is reduced to cyclohexanol (3),

which is oxidized to cyclohexanone (4).

(b) Benzene is ni trated to ni trobenzene (5), which is then

recluced to ani l ine (6). The ani l ine is then converted to cyclo-

hexanol (7), which is oxidized to cyclohexanone.

(c) Benzene is hydrogenated to cyclohexane (8), which is then

oxidized to cyclohexanone (9).

1'he cyclohcxanonc Produccd bYwi th hydroxy lanr ine ( in thc form o[fornring cyclohcxanonc oxirne ( l0).

Cyclohexanotte oxi tne is trcatccl withru n<lcrgocs ihc Bccknrann tr l t rsfornlat iol t( l l ) .

one of several

any of thesc loutcs is rcactct li ts sulphltc Nl ' l "OI{.1{".SO,),

sulph ur ic i tc id , a t t t l

to fornr ca pro lacta nr

262 263

F . t t t l t t t t t t t F F t I F F , FX : S Y N 1 ' I I I ] ' T I C F I N R E S

or-c\t l

(r i);-(ctt '1

-tt lNH, CO -r

CAPROI ,ACTAM

(2) Cycloltexane RoutcBenzene nray be hydrogenatcd to cyclohcxarre ( l ) , which is thcnnitrated (2). The ni tro-conrpound is rcducccl, ior lnirrg cyclo-hexanone oxime (3), which is convcrtcd to caprol : tctanl rs abovc.

B E N Z E N E

o @__ (., .____._-.--,-

CYCLOHEXANE

Capro lac (a rn Proc luc ( ion .

N O " N O l l

l l - - l l\-.' \-,/

CYC LOI]I i XANONI:OXIME

Cyc lohexnr rc l l ou tc .

(3) Cy<:lolrc.t),luninc Ilotttc (uppcr rlilgrarn, plrgc 264 ).An i l i nc i s hyd rogcna tcd to convc r t i t t o cyc lohcxy l t r r r i r r c ( l ) .I - Iydrogen pcroxidc is rcactccl with this to forrn an atkl i t ionconrpound, which is thcn convcrtcd to cyclohcxarronc oxirrrc bylreatnlcnt with nrnnroniunr tungstatc solut ion (2). Thc cyclohexanonc oxinrc is convcrted to clprolactrnr as abovc.

BEt.lZ ENE /'(

\ \ x . , > : :%\^ V -. \J

'a)

(L(t

cYcLor-rExANoNL

Caprol ; rc t r rnrI t rodtrc t io l r . Cyclo l rcxa r r r ;nc l l .outc.

cYcLoll E xAr.lot,lE

I I A N D B O O K O F ' T E X T I L E F I I ] t I E S

o _ * o * o

6i -e- q)" o - g'-e*

N H -

an\-/

ANIL INE CYCLO_ CYCLOTIEXANONEHEXYLAMINE OXIME

Caprolac(am Product ion. Cyclohexylanr ine l loutc.

(4) II exahydrobe nloic Acid Rourafhis is a proccss patented by Sniao[ caprolactarn from toluene whichref ining. Toluenc is oxidized tohydrogcnatcd to hexahydrobenzoicwith ni trosyl sulphuric ncicl in thecaprolactam (3).

Viscosa [or the product ionis avai lable from petroleumbenzoic acid ( l ) which isacid (2). - f rcatment

of thisprcsence of oleum Droduces

[(."").1C O * N H

TOLUENE

Caprolactam Product ion.

HEXAI lYDRO -BENZOIC ACID

Hexahydrobcnzoic

CAPROLACTAM

Acid Routc.

Polyntcrizalion

The polymcrization of caprolactam isor other of two processcs, either (a)(b) an aqueous or hydrolyt ic process.

carr ied out trsual ly by onea non-aqueous process, or

(,a) Non-aqueous ProcessIn. this process,__the carprolactam is heated in the presence ofcatalysts (c.g. alkal i nietals and their sal ts) f l t temperatures ofup to. 280"C. .Polynrcr izat ion procceds by the opcning of thecaprolactam r ings and t l re l inking of the operrecl r ings intopolynrcr nrolcculcs. Thc rcact ion is rapicl , nna higl , molccularweJght polycaproamide may be produce<.! , e.g. wit l i a degree ofpolym.erizat ion in thc regiol of 200. The polyrners are highlycrystal l inc. Tlrcy are general ly superior in pLysical propert iei topolynrers made by the al ternat ive methoj,

-but t l ie proccss is

264

- r r - l ' I

I

B : S Y N T I . I E T I C F t B N E Snot used., as a rule, in the product ion of f ibrcs. l t is of part icularintcrest in t t ie product ion of cast polyan., ia. f tnsr ics.(b) I{ydrolytic process

This is the technique comntonly a<Iopted in thc pro<luction ofpolycaproanride for fibrc .,r-,an u toctu i". 1fi. pr".i* is usuallyopcrated on a continuous basis. Cap,olocioirl,

'rniic-ct wirh aboutl0 pcr ccnt of irs wcicht of wa ter,' tojctfi., *iifi'.lr',f f ing agcnrs(rvhcrc rcq.uircd), acict catalyrt "nr.l niiJ'"r,.;;;i;p.r, lrc fctlcont inuously into the too of a slainless stc"f coiumir, which nr lybe 6 rn (2O ft) high anct45 crn 1f S inl J iai , rc i ;

""" '

r ne colunrn is heatecl to ,250_270.C., an<l as the caprohctnnrf lows.downwards through _the column i t-r" , f"rg". , polymcrizl-

l ron to polycaproarn ide. An equi l ibr iu, "ondlt ion is rcachcd,the matcr ial at the base of thc'column "o"i^ i " i " i "^Uout g9_92pcr cent -of polymer and I l_g pcr ccnt of capiolactnm. , fhcanrount o[ caprolactarn in thc cqJi l ibr iunr rnixtrLr i Jcpcnds uporrthe . temperature; at 260.C., thcrc is " fr"r f i - i ' r r . . . .nt ._ The polymerizario' of caprolacrarn r^k"; ;i.:,;^"; rwo rourcs,(a) a polycondensarion , .o" i ion, " , iJ t rr j "-p '" , 'u i i i ion ,"o", ,o, . , .

Pol y co rttl e nsat i o tt Rcac t i o nThe water added to the caprolactarn as i t cntcrs thc rcact iotr

l::.,.], ":tr as a hy<trotyric agent, ..n.ii,,f *iiir -sonre

or rtrccaprolactarn to form 6-ar.rrino caproic acid.-

T (cH,) -lt - lLao-*"-J

Polycondensat ion of this acid then takes place, sctt ing [r .ccwater which forms more amino caproic acicl irom'ca prolacta nr.This undergoes conclensat ion, contr ibut ing to r i i . l io iynl"r in r io, , ,and so thc proccss gocs on.

Polyaddition RcactiottThc polyaddit ion rcact ion takes.placc t l rrough t l rc opcning oIcap.rolactarn r ings, and the l inking rog"t l r . i u l ' rhe opcnc<lmolecules. There is no intermcdiat" for i lat i i in oi anr ino acid,and lhe react ion cloes not involvc the l ibcrnt ion oi*, , t" l " or othcr

265

ffiI I A N D B O O K O F T E X T I I - E F I D R I I S

srnal l molccules. I t is an addit ion react ion, and not a condensat ionreact ion.

Polyaddit ion takes place alongside the polycondensat ionreact ion, both contr ibut ing to the creat ion of polymer molecules.Polyaddit ion predonrinates over the polycondcnsat ion.

Polymerizat ion cont inues unt i I the amino end groups areblocked by the organic acid wl'rich was added to serve as apolymcrizat ion stabi l izer, 'as in the casc of nylon 6'6 product ion'Polycaproamide made in this way has a degree of polymerizat ionwhich is commonly in the region of 120-140.

The molten polycaproarnide may be spun direct ly at this stage,without any intermediatc isolat iorr of sol id polymer (sec DirectSpinning, below). More conrmonly, i t is extruded from thcpressure vessel as a thick macaroni-like strand which is cooled bya water spray or by fal l ing on to a coolcd metal band. Tlresol i t l i f ied polymcr is clroppcd into stnal l chips of ntaxiuruntdianreter about 6 nrnr (% in).

The chips are rvaslrcd in denrineralized water, which dissolvesout the bulk of the caprolactam; they arc t l ren ccntr i fuged anddried in vacuo at a tentperature below 85'C. The washed anddried chips contain about I per cent of caprolactam'

Spinning

Polycaproamide (nylon 6 polymer) melts at 215-217'C., i .e. about35'C. lower than polyhexamethylene adipamide (nylon 6.6polymer). Molten polycaproamide is conrparat ively stable, andmay be held (under an inert atmosphere) at 250"C. f .or 16-24hours without deter iorat ion. In this respect, polycaproamide isrnuch less sensit ive to spinning condit ions than polyhexanlethyleneadipanride, and the spinning of polycaproamide direct f rom thepolyrnerizat ion vessel may be carr ied out much more readi lythan that of polyhexamethylene adipamide.

Direct spinning of polycaproamide is now establ ished ou i lcornmercial scale, and therc are thus two spinning techniques inopcrat ion for the product ion of nylon 6 f ibres, (a) Sp. inningfrom Polymer Chips, and (b) Dircct Spinning fronr Polymcriza-t ion Stage.

Thc use of one or other of these two processcs is clictatedlargely by the dcgrec of uniforrni ty reqtr i red in the f i lanrents thatare produced.

266

FFffi

(n) Sp,,r,r,,rg ylltilihrncnt yorn lrorn polytrtcr Cltip,

I ] : S Y N T I I E T I C F I I } R I ] S

In the pror luct ion of rnult i [ i lanrcnt yurn, l high clcgrcc ofunifornr iry is-esscnrial , as var iat ions i , ' r ni ;n; ; , l i <Jcir icr ,v i l l rcnato show up in the f inishccl . fabr ic. ln the l rroau"-t io, , oI staplcf ibrc, on the otrrer -rmncr, uni formity is noi s irc i i I 'cr i t ical factor,and greater lat i tude is nerrtr issiblc. Vnriot lon.s Jn f ibr.c dcnicr,within reasonable l imits. wi l l tcnd ro ior. i i r" , r , rc lvcs duringsubsequent nr ix ing anrl proccssing of t t r" . r , ,pi ."ntrr . .rne n lo r t cn po rymer in thc po lyn rc r i za t ion vcssc l r v i l l co r t : r i r r.p to I I pcr cc' t of unchangcct ciproractanr, thc i rctuat ̂ . rorr tvarying with polynrer izat ion condit iorrs. . t . t r is 'conrparat ivcly

highproport ion of a 'volat i le const i t ,cnt i . n unri , t i " ' ' incfor that isl: l: l I.]: :""trol <trrring spinning "i , l l" ,.r,"i i." rnrrcriat, nntlrrrantcnts spun dircct lv fronr lhc nrcl t arc not rcat l i ly l rc l t l wi t l r inll i l:,:.. 1|ra, .". n.""prnbl" ro.,u,,rii i irn,;;;, ';;i. .r.trcy nrc,horv.ever, sal.isfactory for the production of staptc iiUrc.. whe.n polycapronnride is extrutrcd nnd isori i tc<r as crrips, orrthc othcr hand, lhc cxcc.ss -clprolacltrrrr is ,.",, iuu..t [ry rvtr lcrwashing, and thc spinninq of f i irc fro,r i pof y,rr. i" i , ip* ,, ,ny b"control led to proviclc a r iruclr rrrorc- unifornr prodrrcl. . l .hc clr ipspinrrirg proccss, trrcrcforc, is prcfcrrcd i i i i i ,"" ' i ,u,r,,"r ir ' or.nrult i f i Ianrent ya rns.

In the product ion of rnult i f i lanrcnt yarns, t l ry chips of poly_caproanride are al lowed to fal t into t l rc rncl t ing 2o,," 'of n st i r i r r lcsssteel spirrning apparatus. Tlr is. nray "o, l r i r i , ' io." .* l rrrplc, oI nrrclectricatty-hcarcd grict nrainraincd ar "rr" i i i i ib_icb"c.,._lr

,h. chips nrelt,. the molten polynrcr nl*r-rf i-ugr, thc griclrnto a conical-shaped sunrp leading to n nr"i" i l i ig purrrp. . l .hcnrolten polynrer is at al l t inres nraintain.A ,r, iA.i

",, blankct oInitrogcn to prevent oxiclat.ion ona a."onirro.iiiorr.

'

Frorn the,punrp, rhe molren poly,;..- i ; ' f ; ; ;c"j througtr nttcrsconsisting of layers of sand or gract"<r s;r;, ; ;J ironr rrrc r irrcrit . f lows. to 1he spinncrct. This i i a st n i i l".rs -st." i

j isc pcrtoratcrlrvith holes in nunrbcr anrl shapc a"pcn,t iuf on-i", i i i r", l ,", , rr."^, l ir1lr. j : : :-: f . , , ] ]o1,".n

polynrcr cmcrgc inro rhc cort l nir, rhcysurury. Lrunng urc snrnning proccss, thc hcatirrg of thc poiynrcihas te.nded to bring about regcncration of sorne irclc- crr prolrrctn rn,a_nd thc f i lanrents contain u l ig-h", p"r..,rt^g" f*", l ' . ," I p", ""nt;lhan was present in t lrc dry polynr.. . lr ip.,: f i ," pr.-scncc of this267

I I A N D B O O K O F T E X T I L I ] F I D R E S

free caprolactanr prccludes the use of a stean' l condit ioningchamber such as is used in the product ion of nylon 6.6 f i laments;the f i lanrents o[ nylon 6 would become st icky in the hot stearn,and would st ick together arrd to any surfaces they met.

The nylon 6 filaments are conditioned, therefore, by passingover rollers which moisten thenl with water, solutions of antistaticagcnts and lubr icant before being wound on to the package.' l 'hrouglrout

the takc-up region, the atmosphere is control led tosustain a rclat ive humidity of 45-55 per cent and a temperatureof l8-20"C. This ensures subsequent stabi l i ty of the package.

Take-up speeds of more than 1,000 meters per minute are used,and the speed of winding is co-ordinated with that of the meter ingpump to ensure that the f i lament diameter is accurately con-trol led. Packages may contain about I k i lograrn o[ yarn.

Stretchitrg or D rawing

Nylon 6 f i larnents are drawn by passing over two sets ofrol lers, as in the case of nylon 6.6, the second set nroving withsonre 4 tinres the surface speed of the first set. Thc yarn is thusstretched to a rat io of about I to 4. The stretching operat ion iscarr ied out under r igidly control led condit ions, e.g. at 15"C. and55-65 per cent r .h. Drawing may be carr ied out at higher tenr-peraturcs to produce f i laments of higher tenacity.

Twist i ng

Thc rrul t i f i lament yarn at this stagc has l i t t le or no twist .I f addcd twist is rcquired, thc yarn nray be up twisted, usingconvent ional nrachincry, on to perforated bobbins. The degrceo[ trvist is cleternrined by the end use for rvhich the yarn isdestined. A hosiery yarn, for example, may be given a twist of1,182 turns/rn (30 turns/ in) whereas a yarn for weaving orknit t ing may be given only 276 turns/m (7 turns/ in).

lVaslring uttd 7'tvis!-sct tittg

The caprolactam formed during spinning is st i l l present in thcf i larnents of nylon 6, and for some purposes this is betterrcnrovccl. ' fhc yarn is thelcfore washccl in hot water which dis-solves out the caprolactanr. At thc snnrc t i rnc, the yarn undcr '-goes sonle hcat-set l ing which sets the trvist .

268

n .tt r-l ._I r I r I r I r I r I r l 'r" I

D : SYN. t . l r E1 . t c F l l l r (Es

Coning

_ fhe. yarn . is then dr icd, and a sizc isfirral w.inding on to cones. The yarn n-rnl oi*this final winding stage.

appl icd, pr ior to abe lubr icalcd durirrg

l]_:lt^.,1 J"ltrcr is nunrpecl frorn thc pot yn.,cr.ir., tiliilJGl:::?::j:t:l-lts- rhcsc.conrain a.largc nurnl:cr of hotcs, anJthe lilaments.from nrany of rhern ,.. bi"igrr,l'"e",i#",ff;il;Pl,,lo lorgg bobbins. A cable of 5,500 ,f rc- f.,plii,f.n) rnay bcili l;rfifl.in

this wav, provitlirtg o po.t'g.'-*igr'i, 'g ,.i.,riA numbcr o[ these bobbins arc thcn run togcthcr to producc

a tow of 500,000 dtcx (450,000 den) or nlorc.Stretching ol

'l 'ow' l 'hc

tow is passct l ovcr a scr. ics ol l rc:rvy_duty fcct l l . t r l lcr .s wlr ic lrstretch the f i lamcnts in two stages. . l .he' nrst 's iag; strctchcs thctow sonrc 2.5 to 3.O t i rncs, rnd Lhc strctclrct i t -u* t1," , , p, ,rr"*forward to r l re secont l srrcrching ,rug" ; i ; ; ; ; i i is t , .ut"a u,, . tstretctrcd to br ing rhe total strc[h r ;3.5 io a.6-t i , , . r . r .

lYashing, Crinrping an.l CuuingThe stretched tow is passed t l rrough lrot watcr, which cl issolvcsout the bulk of the ciprolactam. i t is i r i "J- i i warrrr air ancrrnay bc trcated with var lous f inishc.. f . i " r f lv, i f r" tow is cr i rnpcdrnechanically and moves forward t" 1ii. "i,it", *i,ich chops irinto the required staple length.

PITOCESSING

Scouring and De-Sizing

(b) Direct Spinning ol Staplc Fibre lrottt polytttcrilcttiott Stttga

Nylon 6_yarns, in conrrnon rvi th othcr synthct ic f ibrc ylrns, t rc::, ' l i l l ly sized.. w.irh polyacryl ic ;,ci,r, 'ef r;, 'p"iy"vin yt n tcotrot,orts or waxcs. AII thcsc sizcs., logcthcr with Air i , sl i irrI i ,)g oi l Ir i jot lrcr contanrinants arc rca,l i iy icnrovcJ by;;; i , ; : i ; ;-The agents used in scouring unry .l.p'"rr.lir",f

'or", tt," n"tur"oI tlrc nratcrial to [rc rcnrovc<t. wtrcrr .pi,r,ii"g

"fi,iirr,r only is tobc renrovecl, a scour with soap or dctcrgcnt

"at SO"C. nray bcadequate. If nn acrylic sizc is

^pr.scnt, il;;;;.;, it"i* n"""rrnru

269

t. , )

[ E t t t t t E tPOI.Y Ht RIZATJON

cli lP i loPPtn

VALVE

MII-I SPINNIIIGcilAfr0t RSPINNIRTTSPINNING5ltAt I

COOI.ING CUTIERWAITR

DRIT.R DRYcli lPs

0008 tN!/ASHrNc

lrt SIAGI 2nd STAGECOTD DRAWING

i l .L lI

' f l corrlc mu ,f ']1, F1LAMENT yARN

I A/51 \

/ tLh:| l \() L':li-'{_:t-'qrDN ItR

ililililflililil||iltICOKING PI.AIII

HYDR0XYl"l l l$!

OXIMEil lr2 0ll

5Ul. P lruRrcACrD ti?5lr

IMHCllrl l l l l

SOOA LYE2ila 0H

coHHoil SAITtHYDRocrMiloNlcYcr"oi lexAN0L

DEIIYDRAIIONCRUDE

CYCTOHEXANONIPH E N0t"

HYDRoGENH2 0 lST lL tAT loN- PURE CYCIOHEXA}IOL

DtSilLtATr0llPURE CYCLOHEXANONE

O N O Hll rl

9Hr Cll, CHr Cl{2cHl,rcHr cu,.cHr

L n 2 L n 2

AHHONIUM5ULPIIAIE SOtU]ION

) p-l, t l

IL

c0Clltci l ,cl l ,cutcl lrN H

LACTAM OIT DISIIttA]ION

MIXINGCHAMBIR

POLYMIRIZATIOIJin vertical tubc

S T A P L E F I B R E

PR€PARATION

I I A N D B O O K O I T T D X ' T I L E F I I J R E S

to usc a scour l iquor containing soda ash, at a temperature of60-70"c.

For heavier soil ing, an en-rulsif ied solvent detergent, a strongcralkali , or botb, arc reconrmended.

In sorne cases, solvent scouring in pure or charged per'chloroethylene is preferred, part icularly in t l te case o[ nylon 6weft-knitted labrics and garments.

Many conrmercial deep dye and basic dyeable nylon 6 yarnsare t inied with a special sightirrg colour and, in this case, i t isnecessary to destroy the dyestufl chentically by addit ion ofhydrosulphite to the scour bath.

lllcnchingPotyamide t ibres in gencral are natural ly white, aud chemicalbleaching is unuecessary except in special circumstances. Bleach-ing nray be necessary, for example, i f heat-sett ing has causcddiscolouration, or i f the nylon is blendcd with other l ibres thatneed bleaclr ing.

Although recomntencled altd used in the past, strong oxidativebleaches such as peracetic acid, sodiunr chlorite and sodiunthypochlorite nlust not be used for the bleaching of nylon 6 asthey can cause excessive oxidation and a resultant reduction it tdyeabil i ty. Moreover, the resistance of nylon 6 to pltotodegrada-tion is often drastical ly reduce(l after such oxidative treatmentsresult ing in unacceptable strength losses alter exposure to l igltt .When the use of an oxidative bleach is unavoidable, e.g. fornylon 6/cetlutosic blends, hydrogen peroxide is the preferredagent; very l i t t le oxidation occurs in this case provided thecorrect cond it iorls are enlployed.

Optical'BleachittgUiually bleaching of nylon 6 is required only for optical ly-briehtened shadei and in this case a reduction bleach usingsta6il izecl hydrosulphite is employed. It is often possible toapply the optical brightening agent from the,b.leach bath makinga separate bleaching treatnrent ul l l lccessary. When.post sett ing isto 6e carried out, the heat sensit ivity oI the whitening agentshould be considere([.

272

rl':ll: t -1 --1 --t -1 "-l '-t --l r'- [ .- r t . [ . ] r l .-l r-1 r-1 -l f-t_]

n : s YN. r . l I e ] . t c l ; l l t l t us

Dycirrg( l ) 100 pc r cen t Ny lon 6

Ihe dyeing character ist ics of nylon 6 are csscnt ial ly sinr i l l r tothosc of nylon 6.6, but dyestul ls tcnd to di l lusc nrorc rcadi ly inlonylon 6 f ibre tharr into nylon 6.6 f ibrc. ' l ' l r is

l r rcnns that wit l rnrany dycs, nylon 6 requires less dycstuf l to attain a givcn shadc,and i ts rate of exhaust ion cxcec<! that of nvlon 6.6__--. Nylon 6 has a nrarkccl af f in i ty for rnarry classcs of dycstul . f .' l 'he

classes with thc wit lcst appl icat io.s aie t t rc ci isp*si : , aci t i ,p.re're tal l ized, cl i rect and selected rcact ivc dyestuf l i cor irbirajt i ons .

As . in thc case of nylon 6.6, basic dycs an<l vat colours trcrarely used. The_basic dyes tcnd to havc poor l ight fastncss; thcvat-dyes are cost ly and di fhcult to apply, havc poor l ight fustncssand low migrat ion powcr.

. As. nylon 6 is hcir t-sct i l t a nt lx intr l l r lct lpcr i l turc of lg3.C.,thc hc.t stabi l i ty o[ thc dycstrr f ls uscd is r iot usuri ly cr i r ic: , i .Carc should be taken, however, in choosing thc dycs. Whcrrsctt ing prcccdcs dycing, i t is csscnt ir l t l rat l r icvcn trcatnrcnt isgivcn, or there nray be sorne di t l icul ty in obt l in ing lcvcl sharlcs.

Metlrcds and Pre paratiottThe techniques used in dyeing nylon 6 are sinr i lar to t l rose uscdin dyeing nylon 6.6. I t is often dcsirable to r lye frorn a sl ight lyhighcr dyebath pl- l and to raise the dycbath i . , , , r , . rr , rr . , , ,or.s lowly to the_f irral lcvel, in orcler to prevent too rapir l cxhaust iorro l t he ( l ycs tu l l . wh ich w i l l resu l t i n unevcn c l yc ins . -

I t is most important that thc goocls sh-orr ld" bc thoroughlyscoured before thcy are dycd.

Disperse DyestulJs1-hcse dyes prescnt fcw di f l icul t ies in appl icrr f ion, and lravccxcel lent migrat ion and level l ing propcrt ic i , cven whcn appl iedat low temperatures. They of ier a wide r ingc of colouri-andare rccommended part icular ly for l ight and mcdium sl tndcs.' l 'heir

covering abi l i ty is very good and incrcascs with r lycing t i rrrcand te rnpera tu re .

A. l though general ly insoluble in watcr, thc dispcrsc dycs trrceasi ly disperscd with the aid of a sui tablc clctcrgcnt; sonlc ncwdyes of this class arc self-dispersing.

r t t l t F , F , t lI I A N I ) I } O O K O I . '

' T D X ' I ' I L D I ; I D I { D S

Dispersc colours arc of two types, (a) nornral disperse clyes,and (b) dyes which are diazotized and developed on thc f ibre.The latter group are sornetirnes used for heavy shades, exhibit inggood rvet fastness with sonrcwhat poorer l ight fastness. Theconverse is true rvith the norntal cl isperse dyes, which havernoclerate l ight fastness antl less satisfactory wet fastness.

Sorrrc of thesc dyes havc a tendcncy to sublinrc on to whitcgoods particularly when exposed to hcat. Many in conrmcrcialusc, however, wil l resist saturated stcam at 120'C. and higher.

Disperse dyes are universally used for hosiery dyeing, butare only suitable for the l ightest shades on warp-knit, weft-knitarrd woven fabrics. The wash fastness of the majority of thcsedyes is insufl icient for dyeing ntediulrr or helvy shades. Lightfastness properties are, on the whole, adequate for most encl uses.

Acid Dyesru[Js

1'hese dyestuffs are used generally lor meclium to deep shacles arrdusually shorv goocl l ight fastness, wash fastness an(l resistance tosublinration. ' l-hey are classif ied corrverriently into tr.vo classes,(a) Acid Levell ing Dyes and (b) Acid Mil l ing Dyes.(a) Ac id Leve I I ittg Dy e s' l 'hese have good levell ing power ancl show goocl coverage ofaff inity variations betrvcen nylon 6 f ibrcs. 1'hey are dyecl generallyfronr a fair ly acidic dyebath, e.g. pFl 3-5.l 'he wash fastness ofacidJevell ing dyes is inferior to that of other acid dye classes andthey are therefore used only for pale ancl uredium shacles orrvhere fastness to rvet treatnrents is not of prime inrportance.

(b) Acitl Milling DycsThis class of dyestuff shols a higher aff inity for nylon 6 ancl

greater care in application is needed. This is achieved by a slowrise in dyebath ternperature, a higher dyebath pl l and by use ofselected anionic ancl cationic levell ing agents. l lecause of thehigher aff inity of these, levell ing arrd coverage of aff inity variationsis nruch poorer than with acicl levell ing dyes but fastness to wettreatnrents is nruch higher. Because of their good all-rounclfastness, acid nri l l ing dyestuffs are suitable for nrost encl uses.

Carcful selection of dyestuffs is irrrportant as blockirrg rnayoccur i f nl onosu lph ol la ted ancl polysulphonatcd dyes arc prcscnt

2'14

s Y N l l t E l r c I r ( u s

in the sarne bath . ' l 'hc r r ronosu lphonatcc l r lye , w i t l r i ts h i r l rc ra l f in i ty fo r ny lon. 6 , w i l l < jye 'prc fercr r t ia i ly anr l sor r re t i r r resf l rspra ,ce the po lyso lphonate . I t i s in rpor tant , thcrc fore , to sc lcc tr.rre ( ly^e^s crrelul ly arrt l trot to use incorrrplt ible rnixturr,s oldyestuffs r.vhen clycitrg cornpountl shadcs.

Prent e t o ll is e tl D1' c s t ulfs' l 'hese lr.e spcci:r l dyestuffs corrrplcxctl rvit lr r: lrrorrr iutrr, tr ickcl orcobait., ' l 'hey have a very high aif irr i ty lor nylon 6 antl thcrcforc

conrrol ot (tyel l lg para.nleters is very i lnportant; for palc slratlcscyc lng rs o t ten car r icd out f rorn a s l ig l r t l y a lka l inc i l ycb l t l r toslow do.wrr the rate ol 'dyei.g. ' lhesc

t l ics i , .u.,roo,i rvct lnst 'cssproperties (conrparablc rvit l i acicl nri l i ing t lycs) but rrc char.uc_,r-r lr:d

lV their very high I ight fastness. t i .cirs6 ol r lr is r lrey rLcrlearly always used rvhcre very. g-ood fastrrcss to l ight is rcqri irc,t l ,c ;S: c r f

l t l j "s , , u ; r l r ,o ls tc ry , c tc . Ur r for t t r r * r tc ly , r r r .s t i i f . thc r ly is t r r t . l . iB lvc Ic lu t lvc ly ( lu l l s l l i l ( l cS.

Cltronte DyestL{fsl 'his class.of dye_ is only of i trtcrcst l i tr spccil ' ic crrt l uscs rvlrcrcecouonric. hcavy shades of high l ight anrl wailr lastncss rrc rc< 1u irc t l .Chrornc.dyes are app l ied. in l s inr i la r luanncr to ac i r l uycs exccptthat, after dyeing, the dyestuff is cornplexccl in a ircsh brihconta in ing potass iunr d ichrornate anr l

- re t luc i r rg agcr r t . 1 .h is

rcsults. in a. .strong..chrolr iunr/dye corrrplcx oi t , igi, l i rstncssbe i 'g lo r l led " in s i t r r " i , thc f ib re . As t r re i ruc sr rade i i t rcvc lopcr lon ly .a f ter th is chronr ing process, co lour r r ra tch inc is d i f f i cu l i rssample swatches have to be aftcrchrornccl before riratching to thcstandarcl pattern can be carriecl out. nnothcr problcnr is t i iat frccchronriunr salts in f inishcd apparel can ciusc Iocalisctl sl<irri r r i ta t ion .

Direct DyestuffsDirect _dyc,s are clrcnrically sirrr i lar to acit l dycs antl lrc usctlprinrari ly for thc dycing of cellulosic { lbrcs. i lorvevcr, sclcctctlt l yes rnay bc uscd for dyc ing ny lon 6 ;app l ica t io r r conr l i t io r rs ln t llas tness proper t ics arc s i rn i l l r to ac id r r r i l l i r rg t lycs .

Reactive Dyest(fs' l 'hese dycstul ' fs arc t lcsigrred for applic:rt iou to cellulosics arrr l

wool. Ccrtairr sclectcd rlyes nray bc uscrl for r lycing rrylon (r arrr l ,275

i l A N D l J ( ) 0 K O t . ' l D X l l L E I ; l t | t { U S

because they fornt a covalent l ink rvith the nylon 6 molecule,very high fastness to washing can be achieved. ' l 'hese dyestulfsf ind only l inrited usage because ol their poor levell ing power andlimited shade range.

I mpro v e nwt in Fas t tressThe fastness of dyed nylon 6 to rvet treatments can often beinrproved signif icantly by the use of a syntan.(synthetic tanningagent) or ful l back tan.' I 'hey should, however, be usecl only whennecessary as thcy can alter the shade, especial ly on subsequentwashing, and can also break down on post heat sett ing.

Deep Dye and Basic Dyeable YantsDye variant nylon 6 yarns arc beconring increasingly comnlon andcan be usecl to give novel colour and white, tone in tone anrl trvocolour effects. The effects produce(l are verv nluch dcDcn(lent onthe <lyeirrg paranrcters uic<l arrr l prrt icuiar attention shoult ltherefore be nrade to dyebath pl l , dyeing auxil iaries anrl dyestuffselection so that the desirecl effect rnay be achieved.

@ nU,,rtt ol f,lyln,t 6 :' fhe rvarnrth of wool and the strcngth and hard-wclring pro-perties of nylon 6 combine to produce highly-desirable blencls.Dyeing of these blends can prcsent some dif l icul l . ies, but they areovercomc by the use of careful ly selectcd acid, prenretal l ized orchronre dyestufls togcther with suitable retarding agents.

Dyes gcnerally have a grelter a0inity for nylon 6 thrn forrvool, and they wil l dye the nylon nrore rapidly and to a greaterclepth in l ight to medium shades. As dyeing continues ancl theshade deepcns, the di l lereuce in tone bctween the two f ibresdiminishes but is st i l l dist inguishable. ' I 'he use of retarding agents,however, reverses this state of aflairs, as the nylon is rctardednrorc than the wool.

ln hcavy shades, thc nylou 6 wil l be conrpletcly saturatcdwith dyc and the excess colour wil l be available for the wool,dyeing it to a deepcr shade in darker colours.

ln addit ion to thc proper sclection of dyestulTs, the typc ofrvool and the percentage of the two f ibres irr the nrixture mustbe taken into considcration in prcparing the dye bath.

- l r l ' l r I

2'16 277

|ll

N : S Y N T I I E T I C F I T I R E S

(3) Blends ol N ylon 6 and Ccllulosic Filtrc.s

For union shades of nylon 6 and cel lulosic f ibrcs, dircct i rnt ldisperse colours are gcneral ly used in thc santc brth. ' l -hc dircctcolours tend to stain thc nylon 6, but this can bc nr ini tnizcd byt l rc usc of a resist ing agcnt. The dircct : rnd dispcrsc coloursshould be preparcd and introduccd into thc bath scparatcly.

IIcal-Sclting

Nylon 6 may be hcat-set ef lcct ivcly at tc l t tpct ' t turcs lowcr l l t i tnthose used in hcat-sett ing nylon 6.6. 1 'his givcs an addcd l lcxibi l i tyto the sett ing process, permit t ing thc usc of dyestu(Is, opt icalwhiteners and other agents prior to heat-sctting rvhiclt rvotrldbe scnsit ive to the temperaturcs enrploycd with nylon 6.6.

Heat-sett ing o[ nylon 6 fol lows the pattern conttnon to thcrrno-plast ic f ibres gcneral ly. Strains which havc bccn cstrbl ishcd irrthc f ibrcs at any st i lgc of proccssing atc rchxcd, l t td thcf ibrcs are sct in thc posit ions thcy occupy t l t rr i r rg sctt i r tg.

' l l r is

gives stabi l i ty and shape permancncc to lhc goot ls.Sett ing may be carr icd out at any stagc during proccssit tg,

from f ibre to f in ishcd garmcnt. ' fhc later thc stagc nt wlt ich

sett ing is carr ied out, the grcatcr wi i l bc thc el lcct otr thc stabi l i tyof the f inal product; strains introduced durirrg proccssirrg thatfol lows sett ing wi l l not, of coursc, be af iccted.

Knit ted and woven fabrics of nylon 6 arc cotumonly l tcat-sct.During sett ing, the cloth must be smooth and crcasc-frcc, bt t trelaxat ion must be al lowed i f residual shr inkagc is to be rcdttccdto an acceptable level. This is usual ly achieved by ovcr-fccdingthe fabric on a pin stenter.

An adequately set nylon 6 fabric wi l l not creasc to any signif i -cant extent in normal washing operat ior ls.

M ct ltod' fwo

rnethods of hcat-sctt ing arc i t t conrrr tot t t tsc, i .c. ( ; r) c lry hclr t ,or (b) wet heat (steam).

(r) Dry Ilcat S(tring

Hot air or gas at 190-193'C. may bc uscd, thc cxposurc t inrcbeing 20-30 seconds, depcnding on the f lbr ic bcing proccsscd.

iI

j r t fI t t

l ii

I I A N D I I O O K O F T E X T I L E F I B R E S

Where steanr inject ion is avai lable, less degradat ion and yel lorvingof the nylon 6 occurs and heat sett ing tentperatures can be raisedto l950C. Infra-red sett ing rnay also be used on sinr i lar equiprnent,the fabric being passed under special ly arranged infra-red units.Very short sett ing t imes are possible with infra-red, owing to thehigh penetrat ion achievcd.

P. in stentcrs are t l re most sui table equipment for heat-sett ingnylon 6, ei thcr by hot air or infra-rcd. Cl ip stentcrs are notsuitable, owing to their infer ior control of the fabric, as they donot ovcrfeed and nray cause dyeing variat ions at the selvedge.Hot rol l machines using heated cyl inders are suitable for stablefabrics, but there is insul l lc ient width control to permit lessstable construct ions to be processed. This lat ter method is thusunsuitable in most cases.

(b) lVet l{eat Setting

Stearn sett ing is carr ied out at 105-l l5 'C., depending on thcfabric and yarn. This technique is most sui table for weft-kni tfabr ics, as penctrat ion is good with this type of construct ion.I t is di f l lcul t to set tubtr lar weft fabr ics in any other rvay.

When batching on a mandrel for steaming, the greatest carenrust be used to get even tension from inside to outside, andto avoid steam escapes through the edges of the batch. Qual i tyof steam is. also important, as excess condensed moisture mustbe avoided i f even dyeing propert ies are to be achicved. Thestcam rnust bc saturated but not superhcated. A vacuum cyclebefore steanring is of great value in obtaining even sett ing, andshould be used whenever possible.

Sl ight var iat ions in treatment may result in not iceable dyeingdif ferences and i t is essent ial that sett ine treatments should beuniform betrveen steaming batches. Sini i lar ly, the size of thefabric rol l should be l imited to ensure complete and uni lonnpene t ra t ion o f s team th roughou t the p iece . ln -so rne cases , pa r t i c -ular ly rvi th warp-knit ted fal tr ics processed on the bcarn, i t ispossible to obtain a good degree ol set by treat ing in hot rvaterat the boi l or I l0oC-. This i I knorvn as i rydroset i ing. Unfortu-nately, fabr ic shr inkage is often excessive and special fabr icconstruct ions to al low for shr inkage are necessary rvhcn sctt i r rgby th i s rne thod .

2'tB 279

: -ll"lr-r]-]-]'-lrlrll-,-iB : S Y N T I I E T I C F I N R E S

sctt ing is crrr icd out dcpcn<.lsthc ccononric point of v ierv,

becausc o f i ns tab i l i t y o f the fab r i c ,to dyc or f in ish, and sci l i r rg rnight bcor aftcr a scour.

Sett ing in thc loornst i r tc rcquircs grcat carc, or sl l ins t luy bcf ixcd result ing in discolourat ion. .sctt i r rg aftc i scouring lxrs thcdrawback

.of increasing t l re numbcr of opcrat ions ncccssary,and di f l icul ty may be expericncccl in obtainir ;g thc rcquirccl y ic iJfrom a grcy fabric unlcss ul lowancc has

*bcen nr irdc in thc

construct ion.

Plclting

Pleats may be heat-sct in nyron 6 fabrics, n.d wi l l wi thst.n(r thce f lec ts o l ' r vea r and wash i r rg . Ny lon 6 n ro r r , . , l i l i r , , r c i i t ( c .g . 22 d t cx ;

?9^l::l]::k"it fabric, tbicxin,ple, is o[tor ti;ri;it for lirrgcri;app l l canons .I lcfore.pleat ing, thc cloth nrust bc scourct l wcl l l r t 60.C.,

op t i ca l l y b l cachcd o r c rycd , an<r thcn c r r i cc r on . s rc . t c r i l t i rnraxlmutn temperatufc of I jO"C. plcat ing should bc cirrr ict l outat 170-180'C., depending on thc plcat inglpcccl lncl s izc of l r lculreq uired.

. When opt ical br ightcning agcnts or <Jycs arc appl ic<l bclorcplcat ing, care nlust be taken to sclect t l iosc rhat , , r" , ,o, , , . , , t_scnsit ive at thc tcntpert tures used.

Tcxlur ing

In cornnron with other thcnnoplasl ic yarns, rrylon 6 r lay bc<lcforrncd by hcrt t I rcatn]ent. to producc Lulked, sirctch or torqucyarns. The false twjst technique, for example, is conrnronly uscd.

Nylon 6 nray be used to produce fat ie twist yarns for nl lcr inrp yarn out lcts, and gtrntents ntadc fronr corrcct ly proccsscdnylon 6 yarrrs havc a di l lcrcnt charactcr fr .ont thosc nrat lc frontnylon 6.6.

Nylon 6 has a lower bending nrodulus lhln nylon 6.6, nncl. this, results in an- unusual ly soft yarn, thc softncss bl iug a111rnrc,,rur t l rc gi lnl tcnt. ' fhc

c[ Icct is plrr t icular ly not iccablc in t t ic c lrrcof garnrents 1>roducccl on nr. , i i , ,m gaugc knit f ing units.

'l'he stage in proccssing at which

upon a number of factors. Frorni t is dcsirable to sct as the f inaltotal numbcr of opcrat ions. This

operat ion, as this rcduccs thcmay bc intpossiblc, howcvcr.

or thc possibi l i ty of danrngccnr r i cd ou t i n l l r c l oo rns t l r t c


ln thc product ion of false Lwist tcxturcd yarns, lowcr tempera-turcs i l re used with nylon 6 than with nylon 6.6.

Filatrrent ortd Yanr DenierI n the product ion of false twist tcxtured yerrrs, thc f i larnentcount is selected with the etrd-use of the yarn in mincl . Fi lanrentsof high cou.nt "vi l l havc a high rctract ivc potvcr in yarn andfabric, atrd they are.suitable, t l ierelorc, for fonn-f i t t iug garnrentssuch as srvintwear, s lacks and trews, stockings, etc. Lowllamentcounts wi l l have less retract ive power, producing a softer andful ler hlrncl in a fabr ic; they are morc suitablc, for cxarnple, foroutcrwear garntents.

S] ' I IUCTUITE AND PROPERTIES

li inc Slructrrrc urrd Appcar:rncc

Nylon 6 f ibres arc sntooth-surfaccd, rvi th no str iat ions. jn nt icro-scopic appearance thcy arc sinr i lar to nylon 6.6 ancl are asfcaturelcss as glass rods. The { ibres are cornnronly of round cross-scct ion, bul. spccial ty1;cs of n. , lorr of nrul t i lobal cross-scct ion arcnow p rod uccd .

'l'en a city' fhe

tenacity of nylon 6 may be varied within l imits by adjust-nrcnt of the ntanufactur ing condit iorrs. In general, the grcaterthe dcgrcc of strctch during drawing, the higher the tenaci iy anclthe lowcr the elongat ion.

J'enacities of typical nylon 6 yarns are as follorvs:Starrdarcl : 39.7-51.2 cN/tex (4.5-5.8 giden), dry; 36.2-45.0

cN/ tex (4 .1 -5 .1 g /den) , r ve t .Fl iglr tenacity: 66.2-73.3 cN/tex (7.5-8.3 g/den), dry;41 .7-

62 .7 cN/ tex (5 .4 -7 .1 g /den) , we t .S ta l r l c : 33 .6 -48 .6 cN/ tex (3 .8 -5 .5 g /dc r r ) , d ry ; 30 .9 -41 .5

cN/ tex (3 .5 -4 .7 g /den) , se t .

Te nsilc Slrength

S tandard : 5 , l l 0 -5 ,880 kg /cn rz (73 ,000-84 ,000 lb / i n : ) .I l i g l t t cnac i t y : 7 ,700-8300 kg /c rnz ( l 10 ,000-120 ,000 lb / i n : ) .

2B0

r.I tI .-I T r-l r I r l r I r I

L I 28 I

S Y N T I I E T I C F T D R I ] S

N1,lon 6

EIonga(ion

Slandard: 23-42.5 per cent, <Jry; 27-34 l)cr ccnt, wcr.Higlr tenacity: 16-19 pcr cent, dry; 19-22 1.;cr ccnt, wct.Staple: 23--50 per ccnt, dry; 3l-55 lrcr ccnt, wcl.

Mastic Rccovery

Like nylon 6.6, nylon 6 is a highly clast ic f ibrc, i r r thl t i t rv i l lrecover i ts ol iginal dir lcnsions aftcr l rc ing dc[orrtrcd by l l rca ppl icat ion of a strcss. .standard f i larnent hai i rn cl i rst ic rccovcryof 100 per cent up to an extcnsion of 6-g pcr ccnt. I lccovcryfrom 10 pcr cent extension is about g5 pcr ccnt._ Recovery fronr cxtcnsion also fol lows i l re pattcrn sct by nylon

6.6, only part of i t being instantnncous, and t i rc rcnruirrdci tal ingplacc over scveral lrou rs,

I I A N D B O O K O F ' I - E X I ' I L I ] F I B I I E S

In i t ia l Modulus

Nylon 6 has a low in i t ia l n todrr lus, i .c . i t s t retches readi ly whensubjected to a s t ress.

Regular f i lanrerrt : 309-44 1.5 cN/tex (35-50 g/den).

Avcrrgc St illncss

l lcgular f i lanrent: 203.1 cN/tex (23 g/den)High tenacity f i larnent: 388.5 cN/tex (44 g/den).

Avcragc Toughness

Itegular I i lament: 0.67.High tenacity f i larnent: 0.68.

Flex Resistnncc

Exccl lent.

Abrasion Resislance

Like nylon 6.6, nylon 6 has an outstanding resistance to abrasion.Scvcral factors contr ibute to this, including inherent toughness,natural pl iabi l i ty, and high f lex rcsistance.

Specilic Gravity

t . t 4 .

Ellect of l\'Iois(ure

Regain: 4-4.5 per ccnt.' fhe moisture absorpt ion increases to a nraxintunr of abor.r t 9 per

ccnt at 100 per cent r .h.- l -he tenacity of wet nylon 6 is 80 to 90 per cent of i ts dry

(condit ioned) tcnacity. The elongat iorr oI wet nylon 6 is sonre.5 pcr cent grcatcr than i ts clry (condit ioned) clongat ion. Tlrcrcis a sl ight arnount of lateral srvel l ing of nylon 6 f ibrc in water,but the lcngth renrains alnrost unaffected.

l'hcrnral Propcrlics

Irlcltittg point : 215"C.

282

t f f i - E F ' l I t t t t t t tl t : s Y N l t u : l l c t ; l l r t t L s

ElJact ot' Low T crn pcratureNylon 6 retains i ts strength wel l at low tcnlpcraturcs. I .hcrc is,in fact, a sl ight gain in tensi le strength aftcr cxposurc of nylon 6at low , te.nrperatures (- 17.C.). The;f icct is rcversiblc, thc nylon6 regaining i ts or iginal strcngth wlrcn returnct l to roonl tcnt_pcra t ure.

I:tJ ect ol ITiglt 7'cnperuture

Nylon 6loses strength with incrcase in tenrpcraturc.. l -hc cf lcctis a condit ion of the thermoplast ic naturc of thc l ibrc, ant l isnot. permanent. The tensi le strengt l t is rcgained whcn t l rc f ibrcis returned to roont tcntpcraturc.

Prolonged exposure of nylon 6 to air at c levatcd tcl t )pcr l turcscauses detcr iorat ion, with pcnltancnI loss in breaking strength,elongat ion and toughness. ' fhc f ibrc <l iscolours (ycl lowg to sonlccx(cnt.

F luttt t trali IityNylon -6_ rescmbles 'y lon 6.6 in l rarnnrabir i ty. r t r 'cr ts rvrrcrr hcarcdabove 215'C., and thc moltcn <troplcts tcnt i to fal l nway. A nylon6 fabric does not norntal ly support conrbusl ion on t ts own, buti l -s I lammabi l i ty may be increasccl by thc prcscncc oI ccrtai trchcmical f in ishcs and d yes.

Iillcct of Agc

Negl igible.

Eltcct of Sunlight

Nylon 6 sufTers sonre loss o[ strength orr prolorrgcd cxposurc tol ig.ht ' u ' i th superf ic ial ycrrowing ancr a gc.cr ' : r l l ic icr iorrr ion otother f i bre propcrt ies.

, Thc <lcgrcc of dctcr iorat ion duc [o l ight is al lcctcd by ntarryfactors, of which thc fol lorving arc inrpo-rtant:

'

. ( l ) 1 'he t ransparcncy o r_op lc i t y o f thc l i b rc . l l r i gh t ny lo r r 6

ts lnore resistant than dul l .(2) ' l 'he.

count of thc yarn. yarns of highcr counr l rc nlor.cresistant thrn those of lowcr corrnt.

283

I I A N D I ] O O K O F T E X T I L E F I B R E S

(3) Dyes and l in ishes used on the yarn. - fhese ntay have a

considerable el lect on l ight sensit iv i ty.

Chcmical Propertics

In gencral , ._nylon 6 is highly resistant to chcnrical c lcgradat ion,and is sinr i lar in this respect to nylon 6.6.

A,[aterials l:Iaving No Pcrnancnt Eflect ott Nylon 6. yurn

Under ordinary condit ions, nylon 6 yarn is not adversely affecteclby cornpounds of the fol lowing types:

AlcoholsAronrat ic t lyt l roculbonsAl ipbat ic HydrocarbonsKetonesEthcrs

Esters'l'hiols

A lka l i sSoaps ant l

Synthet ic l )ctcrgcn(s

Condit ions and chemical agents used for some tests on nylon 6yants arc l isted bclow. Strength and clongat ion determinat ionswere nrade on untrealed yarn and on treated yarn after rvashing,drying and condit ioning.

Undcr the stated condit ions, test results indicatcd no signif icantloss in strength or elongat ion for yarn sanrples as fol lows:

l . Imnrersed in l0 per ccnt aqueous solut ion oI sodiunrhydroxide at 85'C. for l6 hours.

2. Imrncrsed in I0 per ccnt aqucous solut ion of potassiunthydroxide at 65"C. for 3 hours.

3. I rnmersed in 3 per ccnt aqucous solut ion of acet ic aci<l at99'C. for 3 hours.

4. Inrnrerscd in 3 pcr cent aqueous solut ion o[ fornr ic aci<l at99'C. for 3 hours (50 per cent fornr ic acid solut ion at g0"C.dissolves nylon 6 after l5 seconds).

5. Immersed in rnethyl alcohol, ethyl alcohol, acetone, cartroutetrachloride and benzene for 72 hours at roont tentperature.

. 6. Exposcd in a ni trogen atmosplrcre to tc lnpcratures of 150,175 and 200'C. for 3 hours.

' I

2S5

' l r'" I r-r

n : s Y N T l l E . i l C F l n R t i s

7. Exposcd to stcaln atmospherc at 99.C. for 6 drys.

il.Iuterials Having a panttutrctrt ElJect ort Nylott 6 yurtrA 3 pcr cent solut ion of oxal ic ac. ic l in wlter at 99.C. for 3 hourscausqs a Ioss of alnrost 30 pcr ccnt in strcngth nn, l " long"t ion i , ,,,1:l- 6 yarn. Flig.her coriccntrarions, hit;;; i.i.,i.rnrrr" .n.rronger cxposure timcs causc . rapid incrcasc in crrc'ricaldcgradat ion.

Nylon 6 yarns hcl ted in <iry air for 5 hours at 150"C. undcrgodcte.r iorat ion, Iosing hr ightncss anrl bcconri"g V"f i"* .Most of the cornmon bleaches, other than ipi i . " i , ,g.n,r , "uur"somc degradat ion in nylon 6. '

Solve nts for Nylon 6' l 'hc

fol lowing wi l l d issolvc nylon 6:I . Concentrated formic acid (a 50 per ccnt fornr ic lc id solut ionat 80"C. will dissolvc nylon 6 rapi<liy).2. Concentrated hydrochlor ic, ni t r ic ancl sulphuric acids.

Acids

Di lute acids hirve l i t t lc effect ol l nylon 6 un<lcr the condit ionse.ncountered in practical use. Hot mineral acids will, howeucr,decompose nylon 6. The fibres disintegrate in- boitirrg lyAro-chlor ic, acid of .5_ per cent strength, and in cold concentratcdnycrocnlonc, sulphuric and ni tr ic acids.

3. A 25 per ccnt solution of zinc50'c.

4. Phenol and phenol ic compounds.

A lkalis

Nylon 6 has exccl lent resistance to r lkal is. l t c irnstrong caust ic soda solut ions without <tanragc.

Ellcct of Organic SotvenlsConcentrated formic acid, phenol ancl crcsol arcnylon. The fibrc is not attaclie<l by solvcnts "r.O-i"

chlor idc in nrcthanol at

bc boi lcd i rr

solvcnts fordry clcanirrg.

r -J

t t tI I N D O O O K O F I ' E X ' T I L E F I B R E S

l use cts

Nylon 6 cannot serve as food for nroths or beet les.

I\'licro-organ isnrs

Ny lon 6 i s no t a t tacked by mou lds o r bac te r ia .

Elcctrical Pro pcrlics

Surface resistance: 2.0 x l0tz nregohrns.

Spccif ic rcsislat tcc: 2.6x l0s nregohnrs.

Powar lactor: 0.04 at I rncgacyclc; 0.07 at I k i locycle; 0.20 at50 c.p.s. (Al l values dctcrnr ined at 60-70 per cent r .h.)

Diclcct r ic strctrgt l t : 90 kV/cnr.

Allcrgcnic Propcrlics

Nylon 6 is absolutely free of al l toxic propert ics, and is chemi-cal ly inert . I t wi l l not cause irr i tat ion to the skin.

Idcntification of Yarn as Nylon 6 or Nylon 6.6

The fol lorving tesI is used (o cl is l inguish betwcen nylon 6 anclr r y lon 6 .6

Preporation ol Solutiott

A 50 per cent forrnic acid solut ion is prepared by di lut ion oflhe 90 per cent fornr ic acid solut ion comnronly avai lable, e.g.I l i t re of acid is di luted with enough cold water to br ing thelotal volume to 1,800 c.c.

Proccdurc

The 50 per cent fornr ic acid solut ion is heatet l carelul ly to 80'C.Several pieces of yarn or individual f i laments are dropped intothe solut ion. Nylon (r wi l l shr ivel or bal l up rnd dissolve alrnostinrnrccl iately, vcry l i t t lc agitat ion bcing necessary. Nylon 6.6 wi l lf loat in the solut ion and appear not to bc af lccted.

286

B : S Y N ' r ' r E T I C F I I } R E S

The temperature control is vcry inrportant. At Icntpcrarrtrcsscveral degrecs lower than g0.C., nci tbtr nylon 6 nor nylon 6.6wi l l appear to bc, dcstroyed. I f thc temperaturc is at aboJt 90.C.,bolh nylon 6 and nylon 6.6 wi l l r t is intcgratc.

Wh-en making this tcst, i t is advisablc to carry out prcl inr inarytcsts f i rst on knowtr sanrl t lcs o[ nylon 6 ancl nylorr 6.6.

NYLON 6 IN USE

Gcncral Clranrctcrislics

Nylon 6 offers a range of propcrt ics that arc gctrcral lyto_those of nylon 6.6. ' the

chirractcr ist ics of nylon 6.6,inf luence the appl icat ions of thc f ibre, lpply cqualtynylon 6, apart from the effects of the dittcrcric"s bciw"cnpolyanridc l ibres as out l inccl on pagc 201.

' l - l rc fol lorvrng

irr part icrr lar, are inrportant in this icspcct:

s i r r r i la ras thcyrvclI tothc twopoi t r ls ,

( l ) Melr i t tg Point' l hc

l owcr n rc l t i ng po in t o [ ny lon 6 ( tbou t 215 .C . ) us co rupar c t lwith nylon 6.6 (aboLrt 250"C.) nrcans that grcir tcr crrc r trust bctakcn with nylon 6 in al l proccsscs involving thc usc of c lcvatct ltemperatures. Carelcss i roning, for exantple, wi l I damagc nylorr 6more rcadi ly than nylon 6.6.- fhe

Iower nrcl t ing point of nylon 6 inf lucnccs thc opt inrunrtemperalure which nray bc uscd in proccsscs such as hcat sett i t lg.Nylon 6 is heat sct xt temperatures which arc lowcr than thoscusecl for nylorr 6.6.

(2) AlJiniry lor Dye.rtufls' fhe jnc-reased af lni ty of nylon 6 for sonrc typcs of <Jycstul Irnakes for greatcr vcrsat i l i ty in dycing, with the possibi i i ty otproducing br ightcr, dccper pr ints (sec pagc 272).

The extra dye af l in i ty of nylon 6 is :rdvantagcous also in thcprocluct ion of wool/ n ylon blcnds.

(3) Light Sensir iv iry

Despite the increasccl resistance to thc c[ Icct of l ight rvhich isshowrr by nylon 6, i t is st i l l not gcncrnl ly rccorrr nt cnclc<l for t l roscr rscs in w l t i ch cxposurc to l i g l t t i s a l r i r r rpo r tan ( f : r c to r , c .g .cu r (a ins .

287


(1) IIeat Rcsistonce'I 'hc

lorver nrel t ing point of nylon 6 means that i t nray not beused at elevated tetnperatures where nylon 6.6 is still e{fective.At tcmperatures below i ts melt ing point, on the other hand,nylon 6 has a sornervhat bettcr rcsistance to the effect of pro-longed heat ing. This can be an important factor in some uppi i .^-t ions, e.g. tyrcs, rvhere thc f ibrcs must withstan<l elevatedte nrpcra t urcs.

(5) Fatistrc Resistance

Nylon 6 has a bettcr f l l igue resistance than nylon 6.6, and thisis important too in appl icat ions such as tyl .es, where the f ibreis subjected to rcpeatecl stresses.

(6) Hand

In general. nylon 6 goods have a softer hand than those nradefrorn^ nylo_n 6.6. This nray be arlvantageous in applications wherea soft, full hand is desirable, e.g. in tricot and in fabrics madefrom textured yarns. Nylon 6 has been particularly successfulin the tricot ntarket, where its softness has provcd an attractivefea ture.

_.In applications where nylon 6.6 has benelited from its greaterfilanrent rigidity, e.g, in texturecl yarns which have a crisp handassociated with maximum stretch and recovery, it is advisableto use nylon 6 yarns containing f i laments of increased diameterand in fewcr nunrbers. Small increases in cliameter produceIarge incrcases in rigidity, and it is possible in this way to bringnylon 6 yarns more into line with nylor.r 6.6 yarns of similaitotal denier. The increase in filament denier also increases stretchand recovery.

(7) Affinity lor Soltening AgentsNylon 6 has a greater allinity for softening agents than nylon 6.6.Cat ionic softeners are absorbed more rapidly and completely fronrsolut ion, and lhere is a grcater softening ef lect f rom a givenamount of softener. 'l 'his

nrakes necessary the use of finiihingprocedures lhat ensure slow enough absorpt ion of f in ish toprovide a uniform absorpt ion of softener.

288

L T - 1 - - I - - l - - l - l ' [ ' r ' I , t

289

t

-B : S Y N T I I E T I C F T O R I ] S

(8) 7'oughness

Nylon 6 -has a breaking tenacity in thc sarnc r i rngc ts i l rat o[ny ron o .o , bu t the c longa t ion .a t b rcak o f r r y lon 6 i s gcnc ra l l ygreatcr, than that of a nylon 6.6 of s irni lar tcn:rci ty. - f

his meansrnar nylon o has a greater toughncss t l ran nvlon 6.6

(9) Modulus

The ini t ia l modulus of nylon 6 is lowcr tharr that of nylon 6.6,which me_ans th_at nylon 6 defornrs nrore rcaclily undcr a loa<I.This is a factor. in -giving nylon 6 j ts sol ter hancl, as high rnodulustentls to result in incrcascd stillncss.

Thc low ini t ia l modulus of nylon 6 can nrakc for t l i f l icul t icsin processing, as the yarn wi l l stretch casi ly at rc lat ively moclcsttens-ions. In general, howcvcr, nylon 6 nray bc handlcd at tensionssinr i lar to thosc uscd for nylon 6.6

(10) Sltrinkagc

Ot l r c l I h ings be ing eq r r l l , ny lon 6 l i b rcs t cnd fo s l r r i r r k n ro rc i nDol l tng watcr than sinr i lar. yarns of nylon 6.6. . l .h is is :rn inrpor_taxt factor in thc processing of nylon yo.n.. t,i itr" productiorr

of,hosiery, for exanrple, i t has the foi lowin! "ons"or.u"". ,

^ .(il 1:^5, -t11Tsa,ry .ro knit.hose rathcr looscr rhau whcn nylono.o ls uscd, ln order to obtain proper widthwise strctch. Dcpen<l-ing on the mil l handl ing condit ions, this can . . .J i ' ln incrcascdsnagglng rn urc greigc hosc.- (b) To ollset the abovc disaclvantagc, the stitch in finishcdhose of nylon 6 is somcwhat tighter,-an<l .o

-i"*", picks willbe encountered after boarding.

. (9) a high _shrinkagc nronJf i lament may bc a<lvanragcous inhosiery nranufacture. In the procluction of

'tutrirtai stockings, forexample, the f inished shape. is obtnincd ent ireiy by shr inkingthe knit tube to the boarding fornr, and thc l igh shrinkagecoupled with.hjeh elongation is of de,inite a.tvontul"'in producing

a stocking with proper f i t .In certr in non-run stvrcs,-machinc l imitat ions nrakc i t ncccssarythat the anklc be knii raiher. foo... ,f iiigi,"rfiri"f,-g. nylon isagain advantageous in producing a stockirri- wiifr- soiirfo"torv nt.

l t

I . I A N D D O O K O F T E X T I L E F I B R E S

lVashing

Nylon 6 goods are rvashed preferably in handJtot water (up to43'C.) ; b lends of ny lon 6 and cot ton may be washed at ratherhigher tenrperatures, up to about 70'C. White and colouredfabrics may pick up tints from coloured fabrics, and the twoshould be washed separately. Many garments are nrachine-washab lc .

Bleaching is general ly unsat isfactory, and should be avoidccl .

I)rying

Nylon 6 fabrics absorb very l i t t le water, and they dry quickly.Drip drying or cold tumble drying are preferred. Carnrentsshould be given a cold r inse and a short spin (15 seconds)fol lowed by l ine drying. I t is advisable to avoid overloacl ing thespin t l r icr with too lrrany garmcnts.

Ironing

Nylon 6 has excel lcnt qual i t ies of crease resistance and shaperctent ion, especial ly when i t has been el lect ively l reat set. Anrininrunr antount of i roning is required; i f necessary, this shouldbe carried out with a warm iron (HLCC Sett.ing 2), and thegarnrent must be damp. Ironing tentperatures above 150.C.should be avoided. Glazing may occur at higher temperatures,especial ly i f the galrnent is dry, and st icking may occur attemperatures betwecn 180 and 200"C. Excessive exposure toironin( temperatures rnay causd yel lowing.

Previous treatnlent of the fabric has a considerable effect onits rcact ion to pressing and ironing cond. i t ions. Certain <lyes maychange colour at c levated ten)peratures. I [ a change of forrn isdesired, e.g. in creases, pleats or wrinkles, the concl i t ions oftemperature and ntoisture under which the form was establ ishednrust be exceeded to produce a permanent change.

Nolc. Certain garntents suclr as rainlvear and anoraks wi l lof ten have been treatcd with special watcr-repel lent f in ishes whichrvi l l require less severe washing treatmcnt. The same nray applyto qui l ted and l ined garments, and these should be washed inwarnr water and ironed rvlrcre ncccssary with a cold i rorr( l t LCC Sc t t i ng l ) .

290 291

I ) : S Y N T I I E T I C F I B R E S

Dry Clcaning

Nylon 6 is not af lectec l by any of the solvcnts conrnronly uscdin dry cleaning, and no dif l ' icuit ies ar. inuolu.i i . -- '

End-Uscs'I 'he

encl-uses of nylon 6 are gcnerally sirni lar to thosc of nylon 6.6.

Note.I'yre Cortl. Like rrvlon 6_6, nylon 6 has rna<Jc grcaL headwayin- the tyre cord f ic l i . I t is 'c l i inred i i l ' , ; ; l r roi hrs ccrrnirradvantagcs over nvlon 6.6 in this "ppf i . i t i * ,

" "otably thcfol lowing:

(a) Nylon 6 hns grcatcr thcinral stabi l i ty nt thc tc lul)cr i l rurcsencountcred in tyrcs.(b) The adhesion of nvlon 6 to rubber is strongcr i l ran thf l tof nylon 6.6.(c) The f lex rcsistance of nylon 6 is grcatcr tharr that ofnylon 6.6.

I , I A N D D O O K O F T E X T I L E F I I ] R E S

(3) NYLON 1r

Nylon l l f ibre is spun frorn polyundecanamide, nrade by thesclf-condensat ion of 1l-amino-undecanoic acid:

HH, (cr2),0 cooH --->

OMEGA AMINO UNOECANOIC ACID

-- NH (cH2),0 coNH (cHr) ,ocoHn (cH.) ,oco - - -

N Y L O N I I

INTRODUCTION

For sonre years, a nylon-type polyrner has bcen madc in Franccunder the nanre polyamide l l , polyundecanamicle or 'Rilsanite',

prinrarily lor usc as a plastic. The polymer is made by self-condcnsation of I l-arnino-undecanoic acid, and under thenomcnclature scheme used for polyamide fibres (see page 207)i t i s n y l o n 1 1 .

Nylon I I may be melt spun into f ibres, and the production ofnylon 11 l ibres was developed in France by Organico S.A., withthe cooperation of the Ital ian f irrn Snia Viscosa.

TYPES Aryp SrZES OF NYLON lr

Nylon I I has been nlade as mult i f i lanrent yarns, tnonofi laments,staple and tow, in a range of deniers and staple lengths. It wasproduced under the trade nanle 'Rilsan', for. example,in the fol lowing sizes:

F i lanrent : l2 l l , 1212, 1813, 29 I 10, 45 | 16, 57 120, 90 132, 145 i50,290/ r o0.

Stap le : I .4 /32,37, 62 mrn. ;2 .9 137,62,95, l l2 mm.; 6 /40, 70,100, 120 mnt.

' l 'o rv : I10,000 d tex (100,000 dcn) .

!r I

292 293

w

S Y N T I I E ' I ' I C F I D R E S

PITODUCTION

Reaclant SyntbcsisThe I l -arnino-u nclecanoic acid usccl in product ion of nylon I Imay be made by rhrce comrncrci"lly_i,;,;;;;;;;'r"or,"r, (a) fronr

;:jl:i$:.!%.f rom eilrylcne an cl carbou t.t,.,,.i,ro.ia",

. *, J i"j

(it) Castor Oil RouteNylon I I has been produced in Francc arrcl l lrnzi l frorn I l_:unirro_u1de.can9i9 acid madc frorn castor oil (sec bclow). -I-hc

oil isobtained fronr castor beans; it i, "*ii,,it"i fry ii'r" cornbirrc<laction of pressurc an<t orglnic solvcnts. Thc oi l contairrs g5 pcrcent of triglyceryl rjcinolcate.Triglyceryl ricinoleatc is couvcrtcd to nrcthyl r.icinohntc bytfentnrent wilh rncthyl alcohol.MetbyI r icirroleatc is nyrolyzcd at high {cnrpcrirturc, yiclt l irrg^cplaldchydc, rrrcttryl u nclccyl;;;;i. ;,,,i':;'.;;;ii;,;,;r,,, of f. r r yrcid-s ( l). Pure heptaldehyctc anct mcthyl urrJclf i . ; ; ; i ; , , , ." isotarctlby frnctional cl isi i l lat ion.Methyl .undecylcnate is hydrolyzcd lo undccylcrric rtcit l (2).Undccytcuic aci<t is anrir iar., l ' by-r;;" i i ; ; r 'ui i i , ' i , ' . , , . ' ,o,, i , , , ru{onu I I -amino-unclccanoic acid (3).

!

I

II

tl

cr7 ilr. (oH) coocH3ME TI.IYL NICTNOI.EATE

cG t . l r r c i lo

I.IEPTALDETTYDE

+

o

*-

Cl-t. = 611 (Ct-tr)o COOt.t

UNDEC''/LENtC ACtO

^ cHa : cH (CHr ) COOCl r r

(2\ ---')7 METI{YL UI.ID[-CYI.E NN I E

oLr_ {u.{-o_: -y!.rlr c.l!.r_o_ rcac | | )

Production of I I-A nrirro-unclccanoic Acid l.nrru C_.nstor Oil.

Castor oj l is availablc in very lerrge qunntit ics, nntl lhc proccssfor producing I l-anrino_urrac", i , ,oi""n"i, i ' i r ' ; ; t^i; i ; sirrr ' tc arrttstraiglrtforward.

F f t t t l rI

I I A N D I } O O K O F T E X T T L E F I B R E S

Important by-products are produced in this process, includingglycerol, heptaldehydc and residual oils from the cracking stage.' fhese

are an important factor in the economics of nylon I Iproduct ion by the castor oi l route.

Glycerol is used in innumerable industr ics, and is always indemand. Heptaldehyde is converted into heptyl alcohol andheptanoic acid, which are raw nrater ials in the plast ics industry,and are a uscful source of organic chenricals containing a chainof seven carbon atotns. The residual oi ls arc uscd for thc nranu-facture of detergen ts.

The economic development of the castor oi l route to nylon 11is inf luenced, therefore, by a number of factors, and i t renrainsto be seen how successful the process can become' Not leastamong the many considerat ions that must be taken inl .o accol ' l l l tis the fact that castor oi l is an agricul tural chemical. I t is subjcctto al l the variat ions and f luctuat ious that are inherent in theproduct ion of a natural product.

(b) Etlrylenc and Carbon Tetrachloridc Te lonre rizatiort

Telomerizat ion . is, in ef lcct, a polymerizat ion react ion which isstopped after only a few monomer units have l inked together.' fhis is achieved by carrying otr t the polymerizat ion in thepresence of a relatively large anrount of a chain-stopping material,which provides radicals which block the act ive ends of thegrorving polymer chain and so prevent further polynler izat ion.

When ethylene and carbon tetrachlor ide are heated together athigh temperature in the presence of a catalyst (e.g. benzoylperoxide), the ethylene undergoes polymerization until such tinreas the ends of the polymer chain are blocked by Cl and CCl.radicals formed from the carbon tetrachlor ide. Condit ions maybc adjusted so that this occurs after only l , 2, 3,4 or 5 ethylenemolecules, for example, have linked together ( l).

The product obtained by telomerizing ethylene and carbontetrachlor ide is a mixture of compounds of gencri i l structureCI(C.H.,),,CC1., where n is a small number, e.g. I to 5. Oneof the products, which may be separated by cl ist i l lat ion, isl -chloro- I l -trichloroundecane i.e. Cl(CHr), nCCl".

Hydrolysis of this by aqueous sulphur. ic acid yields1l-chloroundecarroic acid (2), which is reacted with anrmonia toproducc I l -amino-undecanoic acid (3).

294

n C.H. * C Cl.

n _ 1 ,

cl (c? Hr)s C Ct3 1.

I ] : S Y N ' T I I E T I C F I N R E S

cr (c, t-t{)n c ctro

2, 3 , 4 , 5 , c tc .

(2)Hzo -:. cr (cH?),o cooH

^ I I -CHLORO -UNDECANOIC [email protected]

NH? (CHr),o cooH

1' -AMINO -UNDECANOIC ACtD

P--rodLrction of I I-Anrin o-undccanoic acid fronr'l 'etrachloride (Tclonreriz_ation).

- -"' Uthy lcr rc a l r r l Carbon

(c) Dotlecane

n proccss for thc producl ion oI urrt lcc:rrr<l lacl i rnt f ronr durlccarrchas been developecl.

I'olyrncrizallon

Polymerizat ion of l l -unclccanoic acicl is carr icd out in thrccstages, the monol ler being fed as an aqucous suspcnsion into thereaction vessel.

Stage l. Water is renrovecl, and the I l_undccanoic acicl .isrneltcd. The temperature is raisccl to 215"C., ln, l - foty"o,r . l "nsa-

t ion begins.

. S.tag9 2. Polycondensat ion is al lowecl to procccd unt i l thcdesired degree of polynrerization has bcen rc:rchcd.

. | toge 3. The ntol ten polynrcr is hcld for a ( i ruea l low the mo lecu la r wc igh t d i s t r i bu t ion to a t t r i ns ta te .

. The molten polymcr is passed to a storagc tank, fronr rvhiclri t may be fed directly to the spinncrets.Note. Tbe basic reaction which occurs during nylon I I prorluctionis as fol lows :

nI-I" N (CFI,),,,COOH+H(FI N(CH,),,,CO),,O fI _r- n _ I I I,O

Spinrr ing

Moltcn nylon I I polynrcr is very stablc i t thc tcnlperature usct l

295

a t 2 1 5 ' C . t oa sn t isfactory

T I A N D B O O K O F 1 ' E X T ' I L E F I B R E S

Mc thy I

Nylon ll Florv Clmrt

296

C A S T O R O I L

A L C O H O L Y S I S

r ic ino leate

Undecylenic ac id

11- amino - undeca noic

A M I N A T I O N

POLYCONDENSAT ION

NYLON , I I

II

I--l

I ] : S Y N T I I E T I C F I N I I E Sduring nrcl t spinning (about 215"C.), and i t nny be .storcd forto 'g pcr iods wirhout acter iorat ion-."d;"; . r^ i , , ; rccarr ions

ar.clll;L:: ffi:$'r:lJl"ion b v m ai n ia i ; ;;s ;;ii ; Jr'"r vrn cr u n d c r

There is l i t t ie tendency_ for l2-rlcnrbcrccl r ing forrnation tooccur during polymerization, "n.1. tt,. nn.,oirrrt."li"* nrolccularwergrrt mater.ial in thc polynrer i.. u.ry "iinif ."l.l," potynl". i,ff ilillIifrJl l,fi::

aficr prod uctio;; ;i r;;,, ; ui,v i,it.,.u,t,riu i"Spinning js carr i id out. in n^,tualtncr sirni lar to thut usct l i r rrry lon 6 producrion. and. r tr ,c_f i rarn;; ; i ; ; ; ; " i ; , ,* ; ro r rrcgrccclcpending on thc type ol rrDrc rccluircd.

PI{OCESSING

l)1.cing

Nylon l l l tas :r lowcr. rr r ois l t rr c . t r bs<_rr.pt iorr lh irrr rry lotr (r or 6.6,and this causc<l sonrc <rvcirrs.,llllliiuf1i"l-.fi,',ii,,""'i, ",arty

rlcvclo'_i:iJJ,,,s;:F:'

sarisfacrory rrycing t"crrni,l;;;: .;,;;

now bccn

,^., | { ; t -a] t izea ant l acctate dyes. give. good rcsurrs, wirrr cxcci lcrr t

i:i:liii ":!"fl:!llii; y.iji,1,,i,i'i^ll*,,11*',1,:,lH i;" ,j,-*lltare usccl with tfiesc dvcs.Nylon l l has an exccl lent resistancc to acicl solut ions, andacid dycing bat lrs of pH as low rs 2 can be trscj c l lcct ivcly.Nylon I I can bc spun_.tv",t'.:tr9"riu.lv, *lrfl"tf,i f",.f p o, n *i.f"range of colouriug marrers..Thc t"* rpii"i"e' t",;urli j ,rr. pcrrnirsor rhc use of nrany orga.ic .ry"rrun

-ro."fi,;,;,u;;;r..

STRUCTUI{E AND PTTOPEITTJES- l -hc

p roper t i es o f nv lon , l l a re cssen t in l l y s i r r r i l a r to t l l osc o fii,,J".,ff.f.;llll,"J1""]""1 i,irsrrruch ,,, ii;;i ,,.',,,ii porv,,,,,i.r.,.:p:: |F

- ;i,, i ",iI "l 11,,.1',i,., h, 1,., ;'J' ;'1, illl_,f ;f ,rill "f li :crrarn oI carbon alonts separat ing thc arni t lc l io, ,-p. 1r". p"g.30e). ' l-hc nroisrurc absorrrion J,;r-.i;.;;;;;;;, i, i i i , rr," .p..iri"f, il;'llili1;.",l;il;"1 u "'* rivron r r t r'"

-riel't..i" r"* iii" r; r'," orr,.,.- l 'he

mel t ing po in t o f ny lon l l i s lo rvcr th i r r r that o t ny lon 6 ,29"1


in accordance with the tendency for melt ing point to fal l with

increase in the number of methylene groups between the amidegroups. But as the methylene groups are an even number, nylon 1l

ialls into the higher of the two series of polyamides. For this

reason, the melting point is not very much lower than that of

nylon 6, which has 5 metbylene groups between amide groups'

and therefore comes in the 'odd-number' series.

Nylott I I

Fine Structure and APPcarauc" /

Nylon I t filaments are sim.ilar in appearance to those of other

nylons. They are smooth surfaccd, and comtnonly of c ircular

cross-sect ion.

Tcnacity \

Fibres miy be produced in a rat lge of tenacit ies by varying the

drawing and other conclitions during productio,n. -Tenacities are

comm;nly in the range 44.15-66.23 cN/tex (5.0-7.5 g/den).1'he

tenacity is vir tual ly unaffected by rnoisture.

'l'cnsilc Strengllt

Fibre of tenacity 66.23 cN/tex (7.5 g/den) has tensi le strer lgth in

the region of 6,deO kg/cmz (98,000 lb/ inz ) .

Elongat ion

Regular f i lament: 25 per ccnt wet or dry '

298

A : S Y N T T I E T I C F I B R E S

[lastic Ilccovcry

100 per cent at 6 per ccnt e longat ion.

In i l ia l Modulus

Nylon - l I has a h igher in i t ia l nrodulus than e i thcr ny lorr 6 or

ny lon 6 .6 . l t i s t yp i ca l l y abou t 441 cN/ tex (50 g / t l c r r ) . -

The higher r i l id i ty of nylon I I givcs i t a bl t tcr <t i rncnsionalstabi l i ty to repeated strxins and a l>cttcr rcsist i rrrcc lo crccp t l t lnotlrer polyam.ides.

Flcx Ilcsislancc

Exccl lent.

Abrasion Rcsislancc

Exccl lent.

Spcci{ic Grnvity

r.04.

Elfect of l\loislurc

Nylon 1l absorbs less water than nylon 6 or 6.6. l t has a rcgainof l . l8 per cent. The nroisture absbrpt ion ao"s , iot incrclsc asrapidly with increasing hunri<. l i ty as in thc .ur. of nylon 6 unt l6.6.

- - Water absorpt ion at 20.C. and 65 per cent r .h. , 1.3 pcr ccnt.Nylon 6 and 6.6 unclcr s irni lar condit lons absorb 4 and 3.6 pcrcent respectively.

Thcrlnal Propcrlics

Melting Poinr: 189"C.Soltcttirtg Point: l7O"C.IJlJcct ol .lIigh. 7'empcrature . Thc behaviour of nylorr I I onprolonged hcat ing is simi lar to that of nylon 6 or 6.6. . l .hcl ibrc yel lows in dry air at I50.C.

Deco_nrposit ion takes place at about 300.C. in i tn i t rcrtr tnrosphcre. Moltcn nylorr I I can bc nraintaincd for rvccks atsp rnn tng ten tpe ra tu re (215"C. ) w i thou t un< le rgo ing dcconrpos i t i on .

299


Iilfect of Sunliglt(

Sinr i lar to nylon 6.6 (special sunl ight- resist i rrg grades areavai lable).

Clrcrnicnl Propcrlics

.,1cirls. Nylon I I is fairly resistant to diltrte nrineral acids. Thereis slow deter iorat ion at high tenrperatures i rnd high concentra-t lol ls.

Alkal is. Nylon I I has a high rcsistance to alkal is.

G cneral . Nylon 1 l has a highcr resistance than other polyamidcsto oxidizing agents. I t is inert to common reagents.

I i f tcct o[ Organic Solvcnls

Nylon I I has a bigh resistance to cornnrolr organic solvents, andis gcncral ly sinr i lar in this rcspect to nylon 6 rrnd 6.6. I t issoluble in plrenols and 100 pcr ccnt fort t r ic i t t td acct ic acids.

Irrsccts

Nylon I I is not attacked by nrot l t grtrbs or beet les.

I\{icro-organisms

Nylon I I is not attacked by nr i ldews or bacter ia.

Dlec(ricll Propcrlics

Nyton I I has excel lcnt electr ical insulat ion propcrt ies, whicl t arerc ta incd under cond i t i ons o f h igh humid i t y .

I landlc

Nylon I I has a plersant, soft handle.

NYLON I I IN USE

Gcncrnl Chnraclcristics

Nylon I I rescr lblcs nylon 6 and 6.6 in nrany o[ i ts i rnportantpropcrt ics, but i t posscsscs features which af lect i ts potent ialappl icat ions in sevcral ways.

' fhc nrel t ing point of nylon I I (189"C.) is otr thc low side for

gencral text i lc use, and great care tnust bc tal :cn in i roning rn<lothcr c lcvu (e<l- tcmperat rrrc treatnrcnts.

- t

300

I

D : S Y N T I I E T I C F I B R N S' fhc

ini t ia l nrodulus of .nylon I I is higher lhnn lhosc of thcljll,ll.llt9:: rcsutring in. inircrse<t stithrJss arrtt r:igioiry. .t.his isaovantageous irr appl icat ions such as brush br ist lc.s, arr tr i t arsonrakcs for easier processing. Nylon f f y, i , . , r . Jo'not strctch socasi ly as nylon 6 or 6.6 yar irs whcn' ," l r i " . t . i to physicrr lploccssing such as winclrng.

The high ini t ia l nror lul t r i of nylon l l srrggcsts lhl t this is l rus.cful nylon for thc hugc tyre cortr nrlrrkii. 'l.yr.cs rcirrfor.ccrr

with nylon l l woulcl not-bc iubjcct r" f f , , i_rr l" t t i l ig ro i l rc cxrcnrl l rat .nylon 6 anrl nylon 6.6 rciniorcct l ,1, , ." . 'n i . ." ' '. The low moisture absorpt ion of nylon I I er iablcs i t to rctaini ts

-cxcel lenr insulat ion propcrt ics nt l r ig lr f r , in i i . f i r i "r ; lh is is :rruscful charactcr ist ic in eicctr ical appl icat iorrs.Nylon I l , with a snccif ic grdviry. of only 1.0.t , is a vcryl ight f ibrc, with nrucrr grerter covcr irrg porvcr tharr l r rc otrrcrpolyarnidcs.

Wnshing

Like..other polyanride f ibrcs, nylo-n i l is easy ro rv:rsrr , t rs irr l ;cond i t i ons s in r i l a r to l hosc usc i l f o r ny lon 6 'und 6 .6 . I : i l b r i cstray be waslred repcatcdly withorrt ycl lorvi i rg. ' - '

Drying

Nylon I I has a low ntoisture absorpt iorr , atr<l t l r ics vcry rnpidly.I t should be dr ied in thc santc rvuv i ts rrylorr 6 arrcl 6.(r rrs ingtctnperalures as low ns possiblc.

Ironing

Nylon I I fabr ic nray be ironcd sl fely l r I tcnl l )cnrturcs in thcregion of 80-100"C. Great carc ntust [ )c lakcn to nvoid usirrgtenrperaturcs which tnight softcn the f ibrc.

Dry Clcaning

Nyl_on I I nr:ry. bc dry crcancd witrr . t r t <r i i l ic.r ty. I r is nor rr i lccrcr lDy rne usual dry clcaning solvcnts.

End-Uscs

Ny lon . I I i s .uscd in a g rca t va r i c t y o f t cx t i l c l pp l i c r t i o r rs . I t i srrndc inlo tr icot kni i lcd l ingcr ic:rrr i l t rnt lcnvcrr, Lnr" a,, .1 ,uuu., ,fabr ics. l t scrvcs in thc sanrc sort of f ickls :rs rrylorr 6.6 i rrr t l

3 0 1


nylon 6. Fabrics of nylon I I are hard wearing and comfortable,rvith all the ease-of-care characteristics associated with nylon6 .6 and 6 .

Heat-setting processes a re used in the same way as with otherthermoplast ic f ibres. Permanent pleats and creases may beobtained effect ively.

(4) NYLON 6.10

Nylon 6.10 l ibre is spun from polyhexamethylcne seblcrtc, nradeby the condensat ion of hexanrethylene diamine and sebrcic acicl :

H.r.r (cr.r.)o tl-r.

H E X A M E T H Y L E N E D I A M I N E

lrooc (cr. )o coorr

SEBAC|C AC|O

---NH. co (cH.)" co ruH (cH.)o r .rx.co (cH.)o co ruu --

NYLON 6 : IO

INTRODUCTION

Polyhcxamethylene sebacate is produced in relat ively smal lrnrounts, largcly for use in plast ics ancl in the manufacture ofsynthetic bristle. Fibres have been spun front it, and they ltavca number of interesting characteristics. Sebacic acid, however,is expensive, and there seemsl l i t t le l ikel ihood of nylon 6.10 f ibrebeing manufactured on a major scale for text i le appl icat ions.

PRODUCTION

Sebacic acid is produccd from castor oi l . I t is condensed withhexamcthylene diarnirre, thc proccss bcing sinr i lar to t l lat uscdin the product ion of nylon 6.6. The product, polyhex anr ethylencsebacate, may be melt spun rvi thout di f l icul ty.

STRUC'I 'URE NND PROPERTIES

Nylon 6 .10 f ib res are s inr i la r to those o f ny lon 6 nnd 6 .6 in many

302 303

rcspects. Thethat of eithcrresilient.

Rcgain

z.o-

Mclting Point

214"C.

S Y N T I I E T I C F I B I ( E S

moisturc absorptiono f ny lon 6 .10 i s l owcr thannylon 6 or 6.6, and ny lon 6 .10 l i b res a rc unusu l l l v

(5) NEW'tYPES OF POLYAMTDE I;tBtrE

lulroduction

Polyamide f ibres in widespread usc today, i .e. nylon 6 ancJ 6.6,have a range of character ist ics which scrv" t t rcnr wcl l in thcgeneral text i le f ic ld. ' l 'hcsc_

I ibrcs hi tvc l r igh tcnsi lc strcngth,which is associaled with a high dcgrce of jasticity; thcy lu-rvcexccl lcnt.bending strcngth and outstanding rcsistancc to nbrasion.Nylon fabrics havc good clirncnsional staliility rvhicli is cnhnnccdby heat sett ing.

The polyarnide l ibres have- a rclat ivcly low spccif ic gravi ty,nraking for l ightweight fabr ics. Thcir rnoistur. '^brorpl io, , i .low.enough_to permit of easy washing and clrying.. This combinat ion of propert ies, togcthcr rvi th

" thosc dctai lcd

rn the.sect ions deal ing with the individual nylons, has crcatcdfor polyamide fibrcs a vast _market which sians alnrost everyf ield. of . text i lc appl icat ion. But i t is incvi taLle t l rat thcre arcapplications for which the range of propcrtics o{Iercd by nylonis inadequate. Character ist ics a. luan[og.ous in one appl icai ionrnay be less desirablc irr other applications, for which n diflcrcntbalance of properties is required.

The. relat ively low moistu-re absorpt ion of nylon, for cxantplc, lcontributes to its case-of-care cha rtcteristlcs. llut it alsocncouragcs t l re accumulat ion of stat ic clcctr ic i ty, wlr ich nray bctundesira-ble or cven dangerous in ccrtain circurnstanccs. -I,hcrcare appl icat ions in which i t would be advantagcous to havc anylon with higher water absorpt ion.

O.ther. propert ics too have provccl inar lcqualc i rr spcci t icappl ical ions. Polyamide f ibrcs gcr icral ly havc I sunl ight rcsistanccwhich is adcquate for normal text i le uscs, but thcy arc attncked

n A N D B O O K O l r - r E X

l ' l L E . F I I i l t E S

too readi ly by ul tra-violct I ig lr t to nrake thcm the preferrct lchoicc in appl icat ions that rnust withstand cont inuous surr l ig lr t .Degradat ion by l ight is cornuronly less serious in the lustroustypes of nylon f ibre than in f ibre which has becn dul led byaddit ion of t i tanium dioxide. Much can be done to improvel ight resistance by the usc of chemical addit ives, but nylon'stcndcncy to undcrgo dcgraclat iou in sunl ight has told aguinsti t in curtains ancl s inr i lar appl icat ions.

Whcn uylon is washed in watcr containing iron salts, i t tendsto absorb the dissolved mater ials, and acquires a yel low colourwhich is di f l icul t to remove.

The ini t ia l modulus of nylon is low, and thc f ibre tbus extendsrcadi ly at low loadings. This nrakes for di f l icul ty in processing,and in ccrtain applications. It is a factor in thc flat-spottingwhich occurs when nylon is used for reinforcing tyres.

Nylon r 's sensit ive to bleaching agents and to acids, and i ttcnds to lose strength when heatcd for prolonged pcr iods, c.g.at lentperatures dbove 150'C.

Thcse character ist ics of nylon f ibres are of l i t t le signif icanceover a vast range of nylon's textilc applications. But in cer-tainapplications, they are sufi"icient to rnake nylon less competitivethan i t might be. And in spccif ic appl icat ions, they may rendernylon al together inadequate.

For most purposes, for exanrple, nylon has an adequateresistance to heat, and the melt ing point - especial ly of nylon6.6 - is high cnotrgh for rrorrnal text i le appl icat ions. In rccenLycars, howcver, developnrcnts in space travel, supersonic f l ightand other lields have created a demand for fibres which canw.i thstand temperatures highpr than those er icountered in every-day appl.ications. The normdl nylons offcr a rangc of propertieswhich is attractive for these specialized applications, but inmany cases their melt ing points are too low to permit of their use.

In nrany clectr ical f ie lds, s imi lar ly, the character ist ics ofpolyamidc f ibres are general ly attract ive, but there are specif icappl icat ions in which they would be more sat isfactory i f themoisture absorption was lower.

I t is apparcnt, therefore, that nylon would be able to play animportant role in rnany special izcd l le lds of appl icat ion i f -cei taincharacteristics wero changed to suit specific needs. Sonre of thesef ic lds, though spccial ized in the sensc that they rnny rcquircpart icular propcrt ics in thc f ibrc, arc of great inrportancc arrd

- l

30{

n : s i Y N T i l D , f l c t : t n R l i s

lbst-rrb,.great quant i t ies of . f i .brc. ' l .yrc

cor.d, for cxarnplc, is a'spccial izcd' appl icat ion which js I nr,r jor or ' , t i " i fo. nylon ant lother fibres.During the I960s ancl 1970s there rvas an increasl l lg awtre-ness of the need for developing polyarnidc fitrr., iuitf , pr"op.ri i.,t lrat would enable them to iorrr.-pcte i 'ore effcctivery in spccializctrfields .rnda nurnber of new types of p"iyuii i, i. ' i i ir ic'canrc on urenrarkct. Sonre of thesc arrcicsig,,eit t i, ,.ru. i i i-.u,,,plrativclynarrorv specializcd fields. Others. h:rve cxtorded tl,. ' ;; i;;-;1general texti le applications ancl brouglrt i irrpioicrircrrts in thccharacteristics of irylon fabric gcnerally.

' '- - '

. 1 'hc.developrlerrt of polyarnicle f ibrcs with propcrt ics t l i l lcrcrr t

f rom the 'standard' nylon f ibres has fol lowcd t l , r" . ' f i , . , " , ,

( l ) Physical morl i f icat ion of cxist ing nylon lypcs.(2) Chcrnicnl rrrodif ict t ion of cxist in6 rrylon typcs.(3) Product ion of ncw typcs o[ polylrni t lc.

( l ) pHystcAl I \ , IODIFICATION Ol: EXtst- tN(; Nyt_oN .t . \ , l , t js

.lVlodilication of polymer

The polyamides from which nylon 6 ancl nyl<.rn 6.6 fibrc.s lrcspun trave been subjcctcct to intensive stucly ovcr a vcry lorrgperiod. A great deal is known about thc cxtcrr t to which thcpropcrt ies of the f ibrc may be nrodif iccl by sui tablc control o[the molecular structurc of the polynrer.

The physical properties of nylon 6 and nylon 6.6 rnay bcnrodif ied within l int i ts by i rr f l t icncing thc nvcr lgc nrolccularweight, nrolecular weight distr ibul ion, dcgrcc of c iy".strr l l in i ty unddcgree of or ientat ion of the polymers. Ful l ar lvantagc is nowtaken of teclrniques such as <trawing which al low thc rnantr-facturer to control tenacity, f lexibi l i ty and othcr trrcchanicalpropert ies.

The extent to whicl l the propcrt ies o[ thc f ibrc nray [ :c var icd. i ' th is way is l inr i ted by thc functar 'c ' tal chcnric i l struct,r"of- the. polyanride. ' I 'hc

nrel t ing point of polyhcxa nrei l ry lcncadipamide. (rrylon 6.6. polynrer). inny b" incr"irs"il, for cxanrplc,by rncrcasing the lnolccular wcight. But a poinl is soorr rcachcdlt rvhich furthcr incrctsc in nrolccultr wcighf has no cl lccl : thc

305

} I A N D T I O O K O F T E X T I L E F I I ] I T D S

opt imurn rnelt ing point for this part icular polyanride has beenreached.

The possibi l i ty of ef fect ing dranrat ic changes in propert ies,beyond those already known, by adjustment of the physical stateof the polymer is thus remote.

Modification of Fibre

M ult i Io b al C ross-Sec t i o tt

It has long been recognized that the cross-sectional shape of afibre has an important influence on many important characteris-t ics, and nylon - in common with other synthet ic f ibres - isbcing produced by some manufacturers in a var iety of non-circular cross-sections. Multilobal cross-section nylons, forexample, are now in large scale use.

The advantages claime<l for mult i lobal nylon hbres include:( l ) increased cover, (2) cr isp, s i lk- l ike, f i rn 'r handlc, (3) rcducedpitling in spun yarn fabrics, (4) iucreased bulk, (5) a sparkle orhighlight eflect, (6) resistan'ce to soiling, cspecially irr carpet yams.The increase in surface area of a multilobal filament, on theother hand, means that nrore dyestuff is required to achieve aparticular shade, and the wash-fastncss is reduced.

'l'e.r ! urct! untl Bulked Yarns

In common with other thermoplast ic f ibres, nylon may betextured and bulked by the various processes in comnon use.A wide variety of yarns modi l ied in this way is now avai lable.

Bicorn ponett Fibrcs I

A rrunrber of bicornponcnt polyanride l ibrcs arc now on lhemarket. in rvhich two l l laments of di l lerent const i tut ion havebeen brought together during spinning to form a single biconr-poncnt f i lament. The two colnponeuts of the trvin I i lamentdisplay di l lerent shr inkage propert ies on appl icat ion of wet ordry beat, and the appl icat ion of heat to the bicomponent f ibrecauscs di f lerent ial shr inkage which produces a cr imp.

I IeterofiI; MeltlirtgI lctcrofi l f ibrcs antl f i latttcrtts are bicortrPorlcnt [ lbres 'uvith acore/sheath structure. Nylon heterol i l f ibres rnay be used [or

306 307

B : S y r . { t i l E t . l C F I D R E S

making non-woven fabr ics (e .g . t .C. t . F ibres ,Carr rbrc l lc ' ) t ry If : lTt. l ._

.: l l . .d, rnelcl ing (a coribination-of rrrelt irrJ and rvcicl ir ig;.lne nereroll t l ibres tnay have a core of relativcly hich rnclt i i icpolnt potymer and a sheath of relativcly low' rrrclt ing poinipolyrrer, which is designed. to f lorv on hcit irrg. Fibre webs arcl l l :11.1 9y t lre application of control led hear antl pressurc, t lrcnDres oelng bonded at cross_over points.

(2) CIIEMICAL MODIFICA'I ' ION OF IJXI.SI, INC NYLON I,YPI:S-Ihe

polyamides fronr whi lh nylon 6 and 6.6 are spun irrcchemical ly act ive mater ials, and ihe structurc of t l icsc polynrcrsT.u.y br modif ied by carrying otr t chcnric l l rc lct ions on thcrn.This provides an opportunity for ' rodi f icr t ion of t rrc chi l ractcr is-t ics of exist ing nylon f ibre types.

During the product ion of nylon f ibrcs, l l tc polyrrrcr rrrolcculcscome _ togcther in placcs

. to fornr rcgiorr i of crysl tr l l i r r i ly.Elscwhere, the long molccules rcr 'ain i ' i nror. o, . rcss rartrorrarrange.ment, . forming regions of anrorphous polyrncr. , l .hccrysl .al l ine regiorrs nrc much lcss rcar l i ly pcrrctr :r tct l by cl tcrtr ic:r lrcagcnts than the antorplrous regions, r incl i t is rnuch casicr,therefore, to br ing about chcnt ical modif icat ion of lhc polyirnt idcin the arnorphous rcgions. crremicar ' rodi f icat ion thus lcnds tohave_ a _more signif icant el lcct on those propcrt ics of thc l ibrcwhich depend chief ly on the. anrorphous ,"gionr, c.g. t lycabi l i tyand moisture, absorpt ion. The mcchanical-propcrl ics, such irstcnacity. and f lexibi l i ty, wlr ich dcr jvc pr inrar i fy f ionr thc crystul-t lne regrons, are less readi ly inf luenccd.

Cross-Linking

The long chain molcculcs.of nylon rnay bc l inkcd togcthcr byreact ing them with chemjcals carrying an act ivc group at cach cnt lof the nrolecule. Thc isocyana tc

' group, fo, "x-nn,pi" , wi l l rcrct

readi ly with amine or carboxyl ic groups, such as rr iay bc prcscntat the cnds of polyamide nrolcculcs. Rlact ion of polyarrr i t lcs witha di- isocyanate, thcrefore, would be cxpcctccl to i ink up acl j tccntpolyamide moleculcs.

l , l r j , technique has. been. used successful ly in attcrnpts tornod l ry ny lon l i b res w i th a v ie rv to i n tp rov i r rg t l r c i r f l a t_spo t t i r rgcharactcr ist ics wlrcn userl i r r tyrcs. Dxposure of rrylorr 6 dr; ;gl ; iabout increased irr i t ia l nrodulus anrl [ower extcnsibi l i ty, rv i t l i a

I I A N D T I O O K O F I ' E X T I L E I : I D R I ] S

signif icant inrprovenrent in f lat-spott ing cha racte rist ics.

Graf t Polymcriz.ntion

The graft ing of polynrers ancl other substances on to the sidcsol polyanridc ntolecules in another chenrical tcchuieue which canproduce substant ial results. Acryl ic acid grafts on nylon 6.6provide sodiunr sal ts which have an attract ion for moisturc.Fibre. treated in this way has high wet-creasc recovery propcrties.

Calciunr sal ts of acryl ic acid grafts tend to raise the melt ingpoint.of the nylon, e.g. to 360.C. or higher depending upon th-clcgrec of graft ing.

Moisture absorpl . ion of nylon f ibres nray be increased by thegra[t polymerizat ion of ethylene oxide on to the I lbre. Tlr i j a lsoinrproves f lcxibi l i ty.

(3) NEW TYPES OF POLYAMIDE

Irilroductiott

During the 40-50 years that have passed since the intensiveinvest igat ion of polyanride f ibres began, mauy thousands ofpolyamidcs have been prepared an<l exanrined ai potential libre-forming. nratcr ials. Evcry conceivablc <l ibasic acid, diamine, anrinoacid and lactanr has bccn polymerizcd, and thc polymer spun intof ibre.

Many of thcse polyanrides have proviclecl fibres which excelin_prrt icular propert ies by cof irpar ison with nylon 6 and nylon6.6. But none has yct been developed commercial ly to the ei tentof presenting a serious challenge to the position of the twoestabl ished f ibres.

The reason is prirnarily an ecorronric one. None of thesepolyanridc l ibres could be produced in the necessary quant i tyand. at a pr ice which would be conrpet i t ive with t6at of theestat l ished nylons. Nor does i t seem l ikely that this posit ioncould change in the foreseeable future.

Nylon 6 and nylon 6.6 are both produced from raw nrater ialscontaining 6 carbon atoms, and undcr prcscnt econornic corr_dit ions these are rnater ials which can be produced clreaply and

308

- t ' l ' I ' [ ' | ' | - | -r -l --r -] '-l

in quantity fronr availablc-raw matcrials. In acldit ion, lhe pr.o-duction of nylon 6 an<t 6.6 has now b""; l;;;"d;.t ro u sragcof lrigh ellicierr_cy, and thcre rs an enor.lous capitar invcstrnc.tin these two libres rhroushout rhc worlcl. li rr;;11;;, potynrrri<tcfibre was ro competc cfl ir ivcty ,;^i; i ; ; ;r;" i i*"rr.r havc roollcr convincing improvemcnrs' in icncrai i" i i i i" ir ,nrn"r.r i . t i .r,and be capable of producrion i, i .onrp*UiJ i i ianfity nt acheaper price.Dcspito thc blcak outlook which faccs clral lcngcrs to nylon 6and 6.6,in the general f icl<j, therc rcnrain grcat Jpiiortunit ics inlhe production o[ new types of polyarnidc for spcciai izcA applica_trons. A numbcr of suclr polyanriclc f ibrcs arc nf..". ly in conr-mercial production, and othcis are un.lcr <Jcv"f"o,"""t.' I 'he

nrost obviorrs l ine ot. approach i"- in"'A.""f"1rnrcnt ofthese uew polyamicle fibres has'fr."n to "*,,,"i,r" 'tlr"

cllcct ofusing diamincs, <tiacids, amino acids ;,,J- ' i ; , ; i ; ; , , ; conrniningnrorc or less than thc 6 carbol atorns prcscnt' i,'t -'ii,a

,,.ru,run,.r.of nylon 6 and 6.6. As would.. fr" ,u, i i" irr" i"r ' f ,"t l , . 'puty",,, i . l . ,prcpared in this wav arc basically si,ul l , ,r ' i i i frr lrrcit ics to rryl.r,r6 and 6.6, but rhc crrang". i , i i i , ; ' ; ; ; ; ; , , ; ' i ld;; i urc nrrr i trcgroups in rhc potynrcr cliin arrccrs ;;;il;,"n;;;;;;;t., i' irrpor-[an[ ways.

S Y N T I T E T I C F r D r r E S

"rl13^:: l !"g poirrt of polyanridcs in a hornologous scrics,

3:,-11f:,:njs to b.e, iowerecr ", ti," "r,i,]rr., '"i

,iil,r,rilii'"f;:ip', ::l*:"j_ j1'". :,1,id". grou ps iu"r"*s... p'i"i rJ ;;";;i;,i,ll:.-rl^"],,:"r _t:ints f ol low rwo cu.rvcs, ".,"

-*pi"r."iiil f;"::ii

:Tl*:i_:t mcthylcn e sroups, and rn;' " rii;r' ;l;' ;;,' ;ii,;i,.r":;methylenc groups. The even numbcrs arc highci iii",r"ililj,inunbers.

has nn cvcn nunrbc r o fgroups, has a nrcl t ing poirr t

o[ nylon 6, with .5 nlcthylcnc

Il: T:l, i ig.t"int.of a polynulid. is incrcasc<t ro a sigrrif icnnr:l:::,t",,:t..Jlj':1,1:1,p.. pt'.nvt"n" .r;;;';;';';' "i;i;",r":espe_cial ly when subsritution is in rhe pnia p;; ir i"; :

I: l: j l l :.1b.:rprion is anorhcr ir;;ri";a pr;pcrty whictr is:,T:l

",t^ I T.,-h: <tistance.bc r wee n t rre a riiirie e;; ;;."';' ;i,. ;i;:il;

:[l: f the number or nrettrytcrc g;;i;;; ;;;:;;";,,l;;ffiti;i l;a bsorption is lowerc<J.l ly adjustment of the scgnrcnt of polyrncr chlr in t l tnr sct) lratcs

Nylon I l , for cxanrple, whiclrnrernytene groups bctwecn the arnidcwhich is only sl ight ly lorver than thatgroups separating the anridc groups.


the anric le groups in a polyamide i t is possible to nrodify theprop.ert ies of the polyamide in signi l ' icant ways. This techniquehas been used in the product ion of polyamides which are nowserving in special ized f ields for which the nornral nylon f ibresare unsuitable. l l igh-tenrpcra ture resist ing polyanrides (e.g.'Nonrex') and polyamides of high dielectr ic strength (e.g. nylonI l ) are cases in point.

NYLON 3

i\4any polyamides have been made by self-condensat ion of thelactanrs of ! -amino acids. Polymers of high rnolecular weightmay be obtained, using polymerizat ion techniques sini lar tothose used with nylon 6. The ease oI polymerization decreaseswith increase in the degree of subst i tut ion of the monorner.

Fibres spun from these nylon 3 polyrncrs are highly crystalline,rvi th nrel t ing poirr ts in the rcgion of 300"C. Decomposit ion tendsto occur at the high tentperaturcs needecl in melt spinning.

Nylon 3 polynrcrs arc di l f icul t to dissolvc, but solut ions havebcen prepared using mixturcs of ntethanol and calcium thio-cyarrate, and f ibrcs have been wet-spun fronr these soltr t ions.

Nylon 3 l ibrcs are character ized by their high nrcl t ing pointsand excel lent resistance to oxidat ion. The af i in i ty for dyes isIower than that of nylon 6

NYLON 4

Nylon 4 f ibres arc spun from polypyrrol idone :

[ - (cH:)3coNH(cH3)3coNH - ]"

INTRODUCl'ION

Polynrerizat ion of pyrrol idonebeen studied by a nunrber ofpolynler have clta racterist icsspecial i ty polyarnide f ibres.

to polypyrrol idonefirnrs. Fibres spunrvhich make thcm

or nylon 4 hasfrom nylon 4interesting as

3 1 03 l l

Nylon 4,.f ibres. have a high _rnclt ing point (273oC). ' l .erracity is

4U.U.cN/tex (4.5 g/den). Water absorptiou is higir; rcgtin i l7.lh rs ls . advanta .gcous in that i t reduces thc tcn t lc r rcy for bu ik l -upoI static electricity and intproves fabric cornfort. Nylorr 4 is rrrorcsusceptible_ than nylon 6 to oxidation ancl is s.nsit iu. to hypo_chlorite bleaches. Fabrics are easy to launclcr and t lry cali ly.

NYLON 5

Nylorr 5 f ibrcs are spun frorn polyvalcrol lctarrr:

[ - N F I ( C H , ) , c o - ] , ,

INl ' I{ODUCTION

-2-pyrrol idone is polynrer ized in thc prcsencc of alkal i catalyst.fhe polymer has a highcr mclt ing pbint thun that of nylor i 6,and. i t tends to dcconrposc rea<l i ly ni tcnr; tenrturcs abovc 265"C.Melt spinning may bc carr icd out with t l i i l icul tv.

PROPEITTIES

Polyvalerolactanr (nylon 5) I ibres have lrccn cxarnincd by anunrber of f i rms, including I .C.I . , du porrt , and - l .cnncssccEastman. Fibres of high qual i ty have bcen obtaincd, rvi th pro_pert ies g-encral ly sinr i lar to those of nylon 6.6. Furthcr dcvclop-ment of nylon 5 f ibres on a comntercial scalc wi l l t lcpcr i t lpr imari ly on the economics of mononrer product ion.

PRODUCTION

PfTODUCTION

Rcacttnt Syntbcsis

Valerolactanr nray bc312). Cyclopentadicncwhich is then oxidizc<loxinre (3) is fol lowe<loroduces valcrolaclant

S Y N T I I E T I C F I B R E S

tnlclc fronr cyclopcnl l t l icnc, (scc p:rgcis hydrogcnutccl to cyclopcntarrc ( i ) ,

to cyclopcntanonc (2). Corrvcrsiorr io lhcby t l re l lccknrann transfornrat iorr rvhich(4).

I ' I A N D B O O K O F T E X T I L E F I N R F , S

o ot l' c '

o

^,_,-'e)I (cHa). 1t lL co-r'ix J

VALEROLACTAM

o t - t't r : ' -

- l lI Ja) l I

c. YcL()P[ l. l lAo ll: l.J E

Pror lL tc t ion of Valero lact lnr

I'olyntcriza tion

Valcrolactanr nray be polyrnerized in a manner sir l i lar tocaprolactam (see page 264 ) at a temperature of about 280-290'C.- l -he polynter produced in this way (molecul l r rveight about15,000- 16,000) is in equi l ibr iunr with sonrc l5 pcr ccnt of lownrolecular weight cycl ic ol igonrers.

Spinning

Polyva lerolactam rnay be nrcl t spun in t l rc samc way as nylon 6.


The propert ies of nylon 5 l lbres are general ly sinr i lar to thoseo f ny lon 6 .6 .

Tenacity

42.4-44.O cN/tex (4.8-5.0 giden). Wet is about 90 per cent ofdry. I : ibres of up to 83.9 cN/tex (9.5 e/den) may be produced.

Elougation

20-28 pcr cent.

Ini t ia l Modulus

I- l ighcr than nylon 6.6.

Crccp Characlcrislics

Nylon 5 f ibrcs have low crccp rt c lcvatcd tenrpcraturcs, arrdlrc an inrprovclncnt on nylon 6.6 in this respect.

312

TL_I-L -t -rt -[ --l -l r_-l r I

B : S Y N T I I E T I C F I I T I I I ] S

Spccific Gravity

r . 1 3 .

Ellcct of Mois(ure

Regain 4. l .

l'hernral Properlies

Melrirtg Poinr : 250-260"C.

CLrcmical Propcrties

E,rcel lcnt resistance to ntost conrmon chcnric l ls ln<l solvcrrts.

INTRODUCTION

NYLON 7

Nylon 7 f ibres are spun front polyhcpta nor r l ic lc (polyocnunt lr l_rn idc o r po lyenan th i rn r idc ) :

[- (crl),,coNH- ],,

Polyheptanoamide (nylon 7) f ibres have bccn dcvcloncd in thcU.S.,S. l{ . under the nanre 'Enant ' . The physical propcrt ics ofthesc.f ibres arc,.general ly sinr i lar to thos; ; f nylon 6 nncl 6.6,but there are di l lerences in certain charactcr ist ics which coutdbe of commercial significancc.

PITODUCTION

Polyheptan oa nr ide is ntade by scl [-condcnsat ion oI c i thcr 7-trrnino_hcptanoic acid or i ts lactanr.

Rcnclant Synlhcsis' fhe

ntonomcr ntay bc rnadc by thc fol lowing routcs:

(n) TclonrcriTatiotr' l 'he

steps in this synt lrcsis arc showu bclow. ' l -c lorncr iza

t ion of

3 1 3


cthylcne in the prcsence of carbon tetrachlor ic le is carr ied out asalrcady dcscr ibcd undcr rrylou l l (see page 294). Onc of theproducts is l -chloro-7-tr ichl oro-hepta ne ( l ) .

Hydrolysis of this mater ial by aqueous sulphuric acid (2)yields 7-chloro-heptanoic acid. Treatment of this with aqueousantnronia (- l ) forms 7-amino-heptanoic acid.

7-chloro-hept anoic acid ntay also be reactccl with auhydrouslurnmonia (4) to fornr heptanoJactam.

3C2H. + c c t . cr (cHr) c cr!o

I - CHLORO -7 -TRICHLORO- HEPTANE

@,k- .n

c t (cftr) cooH : >- NH, (cHr) cooH

7 - CIILORO - HEPTAIiOtC ACtO

l oY

-.-?o(cl-r.L I\i,"HEPTANOLACl 'AM

.l - Arl rNr_o-:_11qgl4lJ_Qlq- ^c,lg

Pror luct ion nf l - Iepta n o lacta nr . ' l ' c lorner izat ion Route.

(b) Cyclohe xattorte Roule

The steps in this synthesis are shorvrr below. Cyclohexanone isoxidizct l to caprolactonc ( l ) , which is convcrtcd to 6-chloro-caproic acid by trcatnrcut with hydroclr lor ic acid and zincclr lor ic le (2).

6-chloro-caproic acid is convertcd to 6-cyano-caproic acid bytrcatnrent with cyanide (3), and the ester of this acicl is thenhyclrogcnatct l to t l lc cslcr o[ 7-arrr ino-hcplanoic l rc ir l (4). I Iydro-lysis of this yields 7-a nr ino-heptanoic acid (5).

3t4

B : S Y N T H E T T C F I B R E S

'..'o,.''(t

o

CYCLOHEXANONE

cr (cHr)5 coorj

6 -CHLOROCAPROIC ACID

?('',,U'CAPROLACIONE

cN (c | r )5 coot t

6 -C'' 'ANOCAPROIC ACtD

Qt '/.r-

)/

l.r l l , (cl{?) coocnr - ( '5)

> Nlr(O.rr) cooH

7 - Al! ' i l t{qt[P rANolc ActD

I'r'oduction of 7-Anrinohcptanr..ric AcirJ frorn Cyclohcxuonc.

Notc

Th.e telomerization proccss is uscd in lhc U.S.S.R., an<.1 is poten_t ial ly an economic routc to nylon 7.

' I 'hc raw rnatci i r ls nr" ' . i l " , ip

and abundant, and thc process i tsel f prcscnts no grcat cl i l l icul t ics.Telomerizat ion produces a mixture of tct rachlo-ro-alk ancs, andthe successful commercial development dcpcnds upor.r thceconomic use of tetrachloro-alkanes othcr than I _chloro.7-t richloro-heptane.

Polymerizatiou

Self-condensat ion of the lnonomer is carr iccl out in a ntanncrsirni lar to that used in making nylon 6, to yielcl a nylon 7 polynrerof molecular weight as high as 30,000.

Spinning

ln-thc absence of oxygcn, nylon 7 is thcrnral ly stablc up to lborrt300"C. As it melts at about 225"C., mclt spirrning nrty be carrict lout without dif l iculty.

Uldcr equi l ibr ium condit ions, nylon ? contains only a vcrysnral I proport ion (about 1.5 per ccnt) of rnonorncr and ot l rcr low

3 1 5

I, l

I I A N D B O O K O F ' T E X T I L E

nrolecular weight mater ials. There is noof ei ther the polymer or the f ibre.

STI{UCTURE AND PITOPERTIES

F I N R E S

necessity for extract ion

has a higher resista ncethan ei ther nylon 6 or

The physical propert ics of nylon 7 arc, in general, intermcdiatcbetween those of nylon 6 and nylon 6.6.

Tcnacity

37 .1 cN/ tex (4 .2 g /den) d ry ;35 .3 cN/ tex (4 .0 g /den) we t .

Elongalion

35 per ccnt.

Ini( ial Modulus

Higher than that of ei thcr nylon 6 or nylon 6.6 at 40-60'C.

Spccific Gravily

1 . 1 0 .

Iillcct of Moisturc

Nylon 7 absorbs less nroisture than ci ther nylon 6 or nylon 6.6.Rega in : 2 .9 .

Thcrnral Propertics

Melrirtg poirrr: 220 230"C.EfJect of IIigh Tentperature. Nylon 7to the effects of elevated temperaturesnylon 6.6.

Ellcct of Sunlight

lJetter resistance Lhi ln ei ther nylon 6 or

NYLON 7 IN USI:

nylon 6.6.

Thc highcr nrelt ing point (by conrparison with nylon 6) and thelorv moisturc absorption could bc important advantages fornylon 7 in ccrtain applications. Coupled with the increased init ialmodulus, the low moisture absorption of nylon 7 nrakes forsupcrior rvash-tnd-wear ch aracte ris t ics.

3 r 6

B : S Y N ' T I T E T I C F T D R E S

In general, i t would seem that the uses of nylonl ine with those of nylon 6 and 6.6.

NYLON 8

Nylon 8 l ibres are spun from polycaprylumi<. le:

[_(CH,),CONt-I_], ,

PI{ODUCTION

7 w i l l f ; r l l i n to

Ileaclant Synthcsis

(A) Butatliene RoutcDinrer izat ion of butadicnc providcs cycloocl:r r l icrrc ( l ) , rv lr ic l tis hydrogenatcd to cyclooctanc (2). Tl i is nr:ry bc convcrtcd tocap.ryl lactarn by routes sinr i lar to thosc uscd in convcnrrrgcyclohexarrc to caprolactanr .(see page 263).

ril /-\ ()CH, :61 '1 - cH=CHr v>

( -_ , ! - fa> -

BUTAOIENE CYCLOOCTA- CYC

\JLOOClANE

(l)) A cctylcnc Routc

Polynrc.r izat io-n of acctylcne produccs cyclooct ir tctrcnc ( l ) , whichrs paruy hydrogcnir tc( l to cyclooctcnc (2). . l - l r is

is oxidizcd tocyclooctene epoxide ( j ) lnd transforrncd lo cycloocrlrronc (4).This is converted to thc oxinrc (5), rvhich undcrgocs ihc Ucck-nrann transformation to capryl Inctant ((r) .

3t7

Capry l Lactarn Prot luct ion. IJutar l icnc l loutc.

T - l ' r - r - r ' t - I - r --I -r -l --I --I --I -r -L A-E

I I A N D B O O K O F ' I ' E X T I L E F I B I T E S

or /:\ (z) a-\c H = c H >

ACETYLENE CYCLOOCTA- CYCLOOCTENETETRENE

o

O" @. /--\..o o a-\zNoH

| .l -'------'- I I\--,/ \---l

CYCLOOCTENEEPOXIDE

CYCLOOCTANONE CYCLOOCTANONEO X I M E

@

[ ,.'.t -l

-co-NH-

CAPRYL LACTAM

Capry l Lactanr Product ion. Acety lenc l t t lu tc .

f<llynrcrization

Capryl lactam polymerizes readi ly to nylon 8 polynrer, in amanner sinr i lar to the polymel izat ion oI caprolactanl. Thepolyrner contains only a very smal l proport ion of low nlolecularweight mater ial (e.g. 0.5-2.5 extractable with water). Molecularweights of 16,000 to 23,000 are readi ly obtained.

Spinning

Nylon I polymer melts at aborrt 200-205'C., and may be melt-spun without di{ l icul ty.

STI{UCI'UI{E AND PIIOPERTIES

A typical nylon 8 polymer, of molecular weight in the region16,000 to 23,000, has properties whiclr are gencrally sinrilar to

those of nylon 6.

l'c n ac ily

37 .1 cN/ tex (4 .2 g /den) thy ;36 .2 cN/ tex (4 .1 g / t l en ) we t '

3 l B

B : S Y N T T I E T I C F I N R E S

Elongation

33 per ccnt .

Specific Gravity

L09.

Ellcct of Moisture

Regain 2.9.

'lhcrmal Propcrtics

Melt ing Point: 200-205'C.

Nylon 9 f ibres

'l'hese fib res

as 'Pe la rgon ' .

PRODUCTION

NYI-ON 9

arc spun f ronr po lynor rnno l rn i t l c :

[- (cH")"coNFI - ] , ,

have been producccl cornrrrcrcial ly iu thc U.S.S.lt.

Ileacl:rnl Synlhcsis

9-amino-nonanoic acid is one of lhe products of the tclorncr iza-t ion react ion (see page 294). In any large scnlc prodrrct ion of othcramino acids by this route, 9-am ino-n onan oic acid woul<l bc areadi ly avai lablo by-product.

I'olynrcrizalion

Self-condensat ion of 9-amino-nonanoic acid takcs placc rcadi ly,and polymers of molccular weight in the rcgion 20,000-25,0fi)are made without di f l icul ty. The polynter contains otr ly a vcrysmal l proport ion of low molecular weight nratcr ial at cqui l ibr i rrrrr(about 0.5-1.5 pcr ccnt extractablc with wntcr).

Spinning

Nylorr 9 polyrner nrcl ts at 210-215"C., and rrray bc nrcl t spun as

319


readi ly as nylon 6. The molten polymer is thernral ly stable solong as i t is protected from atrtrospheric oxygen.

STITUCTURE AND P]TOPERTIES

'fhe character ist ics of nylon 9 f ibres are general ly sinr i lar to t l tose

of related polyamide f ibrcs. The water absorpt ion is lower thanthet of nylon 6, nylon 6.6 or nylon 7. The fol lowing propert ies aretypical of a polynrer of molecular weight in thc region 20,000-25,000.

T cnaci ly

37.1 cN/tex (a.2 g/den) chy;36.2 cN/tex (4.1 g/den) rvet.

Elongation

40 per cent.

Spccilic Gravi(y

1 .09 .

Ettcct of Moisturc

I (ega in : 2 .5 .

Thcrntal Propcrtics

N ' l c l t i ng po in t : 210-215"C.

Nylon l2 f i brcs are

IN'I 'RODUCTION

NYLON 12

spun from polylaurylamide :/

[ -NH(CH") , ,CO_] , ,

Thesc fibrcs havc creatcd considerable interest. Dcvelopment ofnylon 12 f ibres has taken place in France, Gcrrnany and theU.S.A., and there arc prospects of production on a commerciallyinrportant scale as a spccial i ty polyanride f ibrc. Nylon l2 isinhcrent ly cxpensive, horvever, and' i t is unl ikely that i t couldbccome of inrportance as a general purposc polyamide fibre.

' J ' l ' I

320

' t ' r I l ' t - - l

B : S Y N T I . I E T I C F I D N E S

PRODUCTION

Ilcactant Synlhcsisstages in the synthesis of lauryr lactam fronr butacr icnc arc srrownbclow.

I lutadicnc is Lr irncr izct l to l , 5, 9-cycloclodccu tr icnc ( l ) , whichis converted to cyclododecanone (2). This is convcrted to thcoximc. (3), . which undcrgocs thc Bccknrann tr tnsfornrnt ion toI2-a nr ino-dodecanoic acid (4). Thc lactam oI this is lauryll :ctarn (-5).

,CH;Cl1

f'6'� ' \c't

o Hc' !,',HC FH,\ /

cl..!r tct I.cilr_cii

@,.,- l, s,9 -cYcLoDODECATn tE NE

6) (cH,)'\c./

t lI.lotl

CYCLODOOECANONE OXIME

C H , = C H - C H = C H ,

BUTADIENE

(cH- )i ' I l t

\ C /

CYCLODODECANONE

NH, (CHr ) r r COOH

I2 -AMINODOD EC A NOIC

1r,C, )_jo

LAUnYL LACTAM

@-t"

o__--________->

ACID

Product ior r o [ Laury l Lact : rm f roru l ]Lr tadicr rc .

I'olynrcrizrlion

Polycondcnsa t ion of thc ntononrcr is cnrricd out irr thc usullw_ay, and polynrers of nrolccular wcight in thc rcgion 22,OAJ-25,000 nray bc obtained without <l i f l iculty. Nylon l2 polynrercontains ol ly a very small proportion of low inolccull i wcightmaterial (0.75 per cent cxtractablc wi{h watcr).

3 2 1

n F'': F, F'�'�i ti '

I I A N D D O O K O F T E X T I L E F I D I T E S

Spinning

Nylon l2 polymer mel ts at lB0-190"C. , ancl is readi ly nrd l t_spuninto I i bres.

STITUCTU II.E N ND P]TOPEI{II C,S

Nylon 12 f ibres are similar in many characterist ics to nylon 6ancl 6.6. The moisturc absorption is low, ancl dielectric propertiesarc exccllent. The mclt ing point ( lgG-190.C.) is rathei low forgenerir l tcxt i le appl icat ions

The following properties arenrolecular weight in the regiorr'Icnaci(y

33.6 cN/tex (3.8 g/den) dry or wet.

Elorrgation

40 pcr ccnt .

Spccilic Gravity

1 .08.

Ellcct o[ Moislure

Rcga in : 2 .2 .

Tbernral Propcrties

I \ l c l t i ng po in t : 180-190"C.

typical of a nylon 12 l ibre ofof 22,000.

QIANAThis is the trade nanre for a f ibre spun by E.l. t lupont cle Nernoursfronr polymer produced by condensatio n of a trans, trans-di(4-aminocyclohexyl) methane with a dibasic acid containins B-14carbon atonrs, e.g. dodecanedioic acid. .


Tri lobal cross-section. Tenacity 26.5-3 I .0 cN/tex (3.0_3.5 g/clen).Elongation 20-30%. Good recovery fronl streiching. S"p. gr:1.03. lvloisturc regain: 2.0-2.5. Melt ins point 2T5oClChdnri ialstabil i ty cxcellcnt. Dycs wcll to last shadis.

322J Z-t

B : S Y N T I I E T I C F I D N E S

QIANA IN USE

A- lustrous si lky f ibre wit l t nrany characterist ics sinri lar to thoseof nylon 6 and (r.(r. Fabrics r laclc'front eiarra havc exccllent drapcand . lornt retcntion,-and the f ibre hai fourrcl a rcatly rtrarketnotably in the f ield of high fashion.

BICONSTITUENT N YLON_PO LYESl'ER

Fibres consisting of nr icro f i larne nts of polycster r l ispcrscd irr anylon o nratnx posscss unusual optical and dyeirrg charactcrist ics.They have a higher tenacity thin nylon 6:6 a;d lorvcr regrrn.

I] ICOMPON I]N]' NY LON-PO LYESTI]II

Fibres consisting of a polyester core sheathetl irr nylon 6.

AROMATIC POLYAMIDES

It has long been knorvn that the melt i rrg point o[ a polyanridcmay be raised by introducing aromtt ic i i r rgs into thc polynrcrrnolecule. These may bc incorporetcd into t l rc <l i ; rnr inc, diaci t l orboth.

Many aromatic polyanrides havc been nrat lc cxpcrintcrr tal ly,and some are now of conrmercial inrportance as spccial purgrui"(commonly high-ternpcrature resistani) poiyanri<lc ' f . ibrcs.

.The effect of introducing aromatic r ings is part icular ly nr lrkct lwhen phenyleue groups are i ncorporatecl-in tlrc rnolcculc tlrroughthe para posit ions. Meta subst i tui ion provides polynrcrs o[ Iowermelt ing point, internrccr iate between t i rat of thc para subst i t rr tcdpolynrers and those of normal straight-chain cor ist i tut ion.

Polymctaxylylcne Adipanrirte (Nyton MXIH)Condcnsat ion of meta xylylcnc diamine and ldipic aci<l produccspol ymetax ylylcne adipamide, which is commonly known bv thcnanre nylon MXD-6. l ts structure ( l ) is shown bn pagc 324.

I I A N D B O O K O F T E X T I L E F I B R I ] S

Nylon MXD-6 has been examined by a number of firms,rrotably by Celanese Corporat ion, and i t has a number ofattractive features. In particular, its flat-spotting characteristicsare a great improvement on those of the normal nylons, and ithas given excellent results as a tyre cord.Nylon MXD-6 is very susceptiblc, however, to the effccts ofhcat and moisture, and i ts valrrc as a tcxt i lc f ibre is rcstr icted'This rveakness is presunrably due to thc prescncc of methylenegroups between the aromatic rings and the amide groups. Thesepermit free rotatiou of the aromatic ring with rcspect to theanride group. Thc polar i ty of the amide group is low.

Polyhexanrethylcnc Terephthalamidc (Nylon 6T)

Condensat ion of hexamethylene dianrine with terephthal ic acidproduces pol yhexameth ylene terephthalanr ide, or nylon 6T. Itsstructurc (2) is shown on page325).

This structure docs not posscss the weakncss inhcrent in nylonMXD-6, as the amide group is linked directly to the aromaticr ing. Tho molecule is st i f l , and the amide groups are highly polar.Nylon 6T has been studied by a number of f i rms, includingCelanese Corporation, and it has a range of interesting properties.The melting point (370'C.) is too high to permit of effectivemelt spinning, and f ibres are spun from solut ions of the polya-

midc in concentratecl sulphuric acid. Also, special polynrerizationtechniques are necessary,

'fhe structure of nylon 6T resen'rbles a conrbination of thestructures of nylon 6.6 and a polyethylene terephthalate f ibresuch as 'Terylene' or 'Dacron'.. As would be anticipated, thefibres spun frorn nylon 6T conrbine many of the propcrties ofnylon 6.6 and the polyester f ibre. Jhey have the low density,moderate moisture regain, high abris ion resistance, easy dyeing,high alkali resistance and excellent elastic properties associatedwith nylon, ancl the high initial modulus, especially at elevatedtempcraturcs, of the polyester fibres. Nylon 6T has an outstandingrcsistance to stretch, and a vcry high recovery at high tempcra-tures. The flat-spotting characteristics of the libre are similar to

those o[ polyester l ibres. In addit ion, nylon 6T has good heat '

light and chemical resistance, good dye fastness and resistanceto thc cllccts of moistttt'c that are charactcristic of polyestcr fibres.Nylon 6' t retains i ts ful l strength after 5 hours at 185'C. l tdiscolotrrs after I hour al 220"C.,

) z.l

' r

B : S Y N T I I E T I C T T I N R E S

Fully-Aromatic Polyanrides; AranridsThe ntaximr..im e{Iects of introducing arornatic rings into thcpolyamide molecule are obtained by condcnsing uronorrrcrs inwhich, in each case, the functional groups are scparltcd byphenylcne groups, Aromatic dianrincs, for cxamplc, conclcnscdwith terephthalic acid providc polyanridcs with cxccptionulrcsistance to high tcnrpcraturcs. ' fhc intcrnrolcculnr bonding nrrt lchain stillncss arc such as to confcr high thcrnral stability on thcpolymer molecules.

When all the phenylene units in thc polyanridc are pirra-substituted, the optinrum ellects arc obtaincd, and thc polynrcrshave melt ing points or decornposit ion points in the rcgion of555"C. With al l phenylene units in the meta-su bstitr.rtcd posit ion,the polymers melt or decompose at about 410'C.

These fully aromatic polyarnides nray bc prcparcd with thcpara- nnd meta-su bst i tu tcd units in any dcsircrl proportions, nntlthc propcrt ics o[ thc polyurrri t lcs ntay bc sclcctctl nccoLtl irrgly.

Tlre polyanridc shown ns fornrula 3 bclow, for exarnplc, isthe basis of a f ibre dcvclopcd by Chcnrstrand Corporntion.

Fibres fornred frorn polyarnides in rvhich at lclst t |57, of ' t l tcanricle l inkages are attachecl to aroruatic r irrgs arc knorvn asaranids (F.T.C. Delinit ion). Exanrplcs arc 'Norncx' antl 'Kcvlrr 'procluced by E,.1. duPont de Nernours & Co lnc.

o

\a ' - [ " " - .n.6-cH,-NH-co-(c] , , , - .o]

N Y L O N M X D - 6

l- ,--o I--FHN-(q.i^) -NH -co-( \-co-l-L \.=r' l"

NYLON 6T

T - t6 | "^r{) co-r.rrfipr.rH-cofl -rurr-co -?'rrro 4-

L '�- \,t

\er \-/ Jo

Aronrrt ic I 'o lyanridcs.

325

T I A N D R O O K O F T E X T I L E F I B R E S

PII.ODUCTION

Aramids are produced by reaction of aromatic cl iacid chlorides witharomatic dianrines in a solvent such as N.N-cl imethvlformamide(DMF). Polynrers are dry spun from solvent solution into a hotair stream or wet spun into a coagulating bath, fol lorved bystretching.

STRUCTUI{E AND PROPERT]ES

Ararnid f ibres are comntonly round or clog-bone in cross-section.They are pale yellow to crean'l before bleaching. Tenacit ies areh igh, e .g . 38-190 cNl tex (4 .2-21 .5 g /den) i l ry and 28-159cN/tex (3.2-18 g/den) wet. Elongation decreases with increasingfibre tenacity , front 3-30% <lry, 4-21% wet. Recovery,fronilorv stretch is alnrost 100%. Ararnid f ibres are sti f f : resi l iencv andrecovery fronr bending are excellent, ancl abrasioir resistance ishigh. Sp. gr: l .3B- 1.45. Regain 3.5-7.0. Resistance to chenricalsis high, and aranrids are unaffectecl by nrost household chernicals.They are attacked by concentrated acicls ancl oxidising agents athigh temperatures. Heat resistance is high, degradation oCcurringon prolonged heating in air at temperatures above 3700C. Thefibres have very low flamrnabil i ty and are self-extinguishing.Sunlight causes some discoloration and a sl ight loss of tenacity .Aramid fabrics provide effective screens against high-energynuclcar radiation. A good range of fast colours nray be obtainedby using disperse dyes.

ARAMID FIBRES IN USE

Fabrics made from aramicl f ibres such as 'Nonrex' and 'Kevlar'are lustrous and attractive, witK good draping characterist icsand handle. Shape retention anrl wear resistance are excellent.but the high strength of the f ibres can cause pil t ing. Like othernylon. fabrics, aramid fabrics wash easily ancl drip-dry quickly.Dry cleaning does not present problenrs. lroning ntay be-carricclout safely at ternperatures up to 3000C.

Applications for aramid f ibres are conrmonly those which takeaclvantage of the high strength, lorv f lammabil i ty and excellentheat resistance, e.g., special ised astronautical and nri l i tary uses,industrial ancl protective clothing, heat and clectrical insulatiorrmaterials, l i l tration cloths and tyre corcls.

326

n : s Y N ' t l t E r l c r l D t t E s

327

T I A N D I } O O K O F T ! , X ' I ' I L E F I D R E S

2. POLYESTER ITIBITES

INl ' I {ODUCTION

Polyesters are polymers nrade by i r condcnsat ion rcact ion takingplace bctween smal l nrolccrr lcs, in which thc l inkagc oI thenroleculcs occurs through thc fornrat ion o[ estcr groups.

Polycsters are conrmonly rnade by interact ion of a dibasic acidw i th a d ihyd r i c a l coho l :

HOOC-X-COOFt -r- HO-Y-OI{-> - - - oc-x-{oo-Y-oco-x-coo-y-oco - -

The lormation of polyesters was studied by Wallace H.Carothers of du Pont during the invesl. igat ion of polynrers whichlct l cvcntual ly to thc discovcry oI nylon. Dcvclolrrncnt oI t l rcpolycsters was overshuclowed, horvever, by the polyarnideresearch, and i t rvas not unt i l l94l that a valuable polyester f ibrervas discovered. ln that year, J. T. Dickson and J. R. Whinf ieldof the Cal ico Printcrs ' Associat ion in England made a synthet icf ibre frotn polyethylene terephthalate by condensing ethyleneglycol rv i th terephthal ic acicl (see pagc 332).

Aftcr thc wnr, development of the f ibrc was carr ied out underl iccnce by LC.L Lt( | . in the U.K. and by du Pont in the U.S.A.,rcsult ing in thc f ibrcs knorvn rcspcct ively as 'Terylene' and'Dacron' .

Today, polyethylene terephthalate f ibres are being made inmany countr ies, and nrodif ied forms of this f ibre are alsoproduced. Other polyesters have been produced and spun intofibres, some of which have beconre oI commercirl inrportance(cf- 'Kodel ' ) .

TYPES OT. POLYESTIIR FIBRE

In the years since World War lI, polyethylene terephthalate fibresof tho 'Terylene' and 'Dacron' type havc established a dominatingposition in the polyesler fibre lield. Other types of polyester have,however, been spun into fibres with varying degrees of practicalsucccss. and a few of these have bcconre of conrrnercirlinrpo rta nce.

328

T r - l r l r l - l . l . l ' l ' l ' I ' l ' l

I } : S Y N T I I E T I C F I B R E S

The posit ion l rrs now bcen reachccl where i t is prcfcrablc toconsider polyester f ibrcs as. specif ic typcs, i , rscct ' rrpon t trc irchcnrical structurcs. 'I'hc_ ,ifl'crcnc.. il;;";--il*r' irrc Ioosignit icant to permit of rheir being considcreJ; i ;pi ; ; , .polyesrcr,

fibres.

. . For the purposcs of the I{andbook, polyester f ibrcs trc sub-dividcd into thc fol lowirrg typcs, bascd , ,pon i i , " i , chcnric l lstructures, and thc abbrcviat ions shown nrc i rs. , f in rcfcrr ing tothe fibrcs :

( l ) Polycthylenc Tcrcphthal i r tc Fibrcs (pE.f polycster I ; ibrcs).(2) Poly:l^4-Cyclohexylcne-Dirncthylenc fcrcphthalatc Fibrcs(PCDT polyesrer Fibrcs).(3) Othcr Types of polyester Fibre.

NOMI'NCLA.TURI]

The f i rst polyester I ibres to be introduced on a conlnlcrciul scalc( i .e. . 'Dacron'_and,Tcrylcnc') *" ." .yrr , . ' f r .or i i "poty"thyl" , ,c

terephthalate. This chenrical term was, 'of "or. , i r . , too cornplcxfor everyday use, and rhe f ibrcs b;"n,;"- i ; ; r ;n sinrply as'polyester ' f ibres. They are st i l l kno*n g.n.r . i ly Ly t t r is tcrrntodav.

__ llie lcrm 'polycster'

is., howevcr, a specific chcnrical nanre whichrclers to any polynrcr i ' which thc r inkagc of snralr ' rolccurcstakes, place. through thc fornra( ion "f ; ; ; ; ; r""ps. I t rcfcrs

:::i l l",::l!, jg1 exalntc, ro .polyerhyten" .,ti i"inir. nndc by:onq:n.sr13 ethylene glycol with. adipic acid, or to polypropylcrrcterephthalate madc bv condcnsing p.oiyi., , .

' glycol"wirh

terephthalic aci<I.- In the sclcction of .oll'icial' names for synthctic fibrcs o[di{Ierent types, the U.S. Federal fmA" Conrnri'ssio,i iu.tua.a tt,.term 'polyestcr' . anrl spccil ied th:rt this nrust bc uscd for f ibrcsor.tnc potyculytcne tcrcpll thalatc type (scc bclow). . l .his was lrrrunr.onunate choice, as this dcl init ion of ,polycstcr; is at varirnccwith the chcmical meaning of thc tcrrn. C;"i; i"; coul<l havcbeen avoided if a conrolcrcly new, non_ctrci;;i-;, (cf. nylon)had been coinccl instcacl oi using a tcrnr wiih

-a wcil-OcnncAchcrn ical mcaning.

Under thc prescnt F. ' f .C. rcgulations, i t is possiblc for n

329

rF,H A N D B O O K O F T E X T I L E F I B R E S

polyester fibre to be marketed which does not meet the F.T.C.del ini t ion, and could not, therefore, be cal led a polyester f ibre!

Federal Trade Cotnnissiott Delinitiotr

The generic terrn polyester was adopted by the U.S. FederalTrade Commission for fibres which satisfy the following officialdef ini t ion:

Polyester. A manufactured fibre in which the fibre-formingsubstance is any long-chain synthet ic. polynrer conrposed of atleast 85 per cent by rveight of an estei of a subst i tutecl aronrat iccarboxyl ic acid, inclucl ing but not restr icted to subst i tutedterephthalate units p(-R-O-CO-C6H4-CO-O-) and para-subst i tuted hydroxybenzoate units p(-R-O-C6Ha-CO-O-).

(I) POLYETFIYLENE TEREPHTHALATE FIBRES(PET POLYESTER FIBRES)

Fibres spun from polyethylene terephthalate:

--- o (cHr). oco Q coo (cH.).ocoOcoo (cH J.o ---

POLYETHYLENE TEREPHTHALATE

INTRODUCTION

The discovery that potentially-valuable textile fibres could bespun from polyethylene terephthalate (PET) (see page 334) wasmade by Dr. J. T. Dickson and Mr. J. R Whinf ield in 1941. inthe laboratories of the Calico Printers' Association Ltd. inLancashire, England. Development of the PET fibre was held upduring the war, but in 1947 the world r ights to manufacture thenew fibre, with the exception of those for the U.S.A., werepurchased by Imperial Chenrical Industries Ltd. (E.I. du pontde Nemours and Co. Inc. bought the r ights for the U.S.A.).

In Bri tain, the manufacture of PET f ibre began on a pi lotplant scale in 1948, the f ibre being marketed under the name'Terylenc' . Sincc then, product iorr of 'Terylene' has expandedrapidly. At Wilton in Yorkshire, I.C.I. Ltd. have speut nrillions

330

B : S Y N T I I E T I C F I I ] R E S

of pounds in the construct ion of 'Terylcnc' plants. In Jtnunry1955, a large plant came into product iorr , with an annual caplci tyof 5 rni l l ion kg divided alnrost eclual ly betwecn f i l r rrrcnt yarrranc l s tap le .

In 1956, a second unit of s imi lar capacity began product ion,and th i s was fo l l owed by a " l ' c ry lene 'p lan t i n Nor t l r c r r r l r ch r rd .

In thc U.S.A., the du Pont company bcgan producing lrE' ff ibre on an experimcntal basis in 1950. The f ibrc wls known ini ts early days as'Fiber V' , but was subscqucnt ly givcn thc tmtlcname 'Dacron' .

PET polycster f ibres are now being producct l in urany courr t l ics.

TYPES NND SIZES

PET polyestcr f ibrcs are produccd as nrul l i f i l l r rncnt yarrrs, rutrno-f i l an ren ts , s tap le f i b re and to rv , i r r a r v i t l c n r r rgc o l ' cou r r t s u r r r lstaple lengths to sui t v ir tual ly al l tcxt i le rcquircnrcnts.

The f ibres are avai lable in br ight, scnridul l lnd dul l lustrcs.The propert ies of the f ibres may be nrodif icd ovcr a rangc whiclris l inr i ted by the inhcrent charactcr ist ics of thc polynrcr, caclrmanufacturer control l ing his proccss to produce f ibrcs that wi l lmeet specif ic requirements. In general, commcrcial PE, I polycstcrf ibres fal l into two main classes, (a) regular tcnacity nnd (b) higlrtcnacity.

PET polyester I ibres are produced comnronly in round cross-sect ion, but l ibrcs of spccial (e.g. t r iangular) cross-scct ion trc nowavai lable from a number of manufacturers.

PET polyester f ibres are thcrmoplast ic, and lcnd therrrsclvcswel l to physical modif icat ions associatcd with this propcrty.Crimped and texturcd yarns of al l famil iar typcs arc nvni l tblc.

PRODUCTION

madc by thc condcnsat ion of

3 l l

Polyethylene terephthalatc is

T I , \ N D B O O K O F T E X T I L E F I D I I E S

terephthal ic acid, or a derivat ive such as dimethyl terephthalate,rvi th ethylcne glycol.

cooHrn a\ -L\:,/

\.J'cooH

TEREPHTHALICA C I D

coo cH"

6\ a\ r-" \.',coo cHl

coo cH.7-\,| i l\,l,

coocHsDIMETHYL

TEREPHTHALATE

coo cH, cH,oH7'n- > t t l\./

COO CH? CHaon

D I E T H Y L E N EGLYCOL

TEREPHTHALATE

cHr oH

METHYLALCOHOL

c H , o Ht -cH20H

ETHYLENEGLYCOL

--- o (cu.).oco Qcoo 1cx.),o.o() coo(cHa)20 ---


Production of polyethylene terephthalate

Reactant Synthesis (see diagram page 333).

(a) Ethylene GlycolThis is made by the catalytic oxidation of cthylene, which isobtained from petroleum cracking. Ethylene oxide is produced (l).Hydration of this yiclds ethylcne glycol (2).

(b) T'erepluhalic Acid; Dinrctlryl TerepltthalatePara-xylene obtained from petrolcunr is oxidized (3), for exarnplewith nitr ic acid or with air in the presence of a catalyst.

Terephthalic acid is esterified with nrethyl alcohol (4) to forrndimethyl tcrephthalate.

- t

332 J J J

s Y N ] i l E r t c F i l i l t E . s

9H' O( a ) l l +c l l2

o( b )

ETHYLENE

f H, . r - @ c t . t ,o r - ll - n lc H { c l t r o l l

ET I IYLENE ETI IYLEI ' IEOXIOE GLYCOL

cooll coocilra''x @ 4\</ </

COO|I COOCl t r

c f l .

/r;t t l

C H ,

P . X Y L E N E

PET Polycs(cr

T EREI } I ' IT I IAL IC DIMET I . IY I -A C t O 1 E R E P H I H A L A r t :

F ib rcs . l ) ro r luc t i t r r r o f r r ro r r o t r rc rs

l 'o l l nrcr izrt ion (scc diagram pagc334).

Polyethylenc terephthalale- i \ .madc by conclcnsing ethylcrrc glycolwith ei ther tcrephthal ic acid i tscrf or witrr <l inrct l iy l tcrcplr tr ia lr tc.

Condensat ion of etbylenc glycol with tcrcpht l ia l ic acid ( l ) isan ester i f icat ion react ion, watcr bcing el inr inatcd as thc rcaci iotrtakes place. Condcnsat ion _of cthylcnc glycot with dinrcthyltcrcphthalate (2) is an cstcr intcrchang" ," i " i ion, rncthyl alcoholbeing el inr inatcd as the rcact ion takes placc. 1-hc polyrncrobtained in this way rvould be expcctecl to havc an cstcr cnclgroup instead of the carboxyl ic acid cncl group in thc case ofthe polymer obtained by the tercphthal ic ai ic l route.

In ei ther casc, the condcnslt ion is carr ict l out by hctt ing thccthylcne glycol

.and tcrcphthal ic acicl or dinrcthyl tcrcpht l ia lnteand removing thc water or nrcthyl alcohol i r r vaclo. When thcdcsircd degree of polyrnerizatiorr hrs bccn reachcrt, the clcar,colourless polyester is extrudccl through a slot on to n cast ingwheel. Tlrc polynrcr sol idi f ics into an endlcss r ibbon, rvhich isfed to a cutter rncl cut into chips in t l rc lornr ol ' cubcs rvi f l t3-6 nrnr ( l lB - 114 in) s idcs.

.1'he cl t ips are dcspatchcd to the spinning rooru via a suct ionp tpe .

D : S Y N T I I E T I C F I I } R E S

I I A N D B O O K O F T E X T T L E F I B R E S

HO (CHr)roH

ETHYLENEGLYCOL

"ol--oc( )coo1cu,1,o- | H + H'�o' | \ / . J n


lO l

r q '

\

o

t--{lrJ

:

i

@

l v v v , , l

I ' l l +

coocllt

Ho (cHr) oH

POLYETHYLENETEREPHTHALATE ^YEL?.|!..

Pro<luction of polyethylene terephthalate

Spinnlng

Polyethylene terephthalate melts at about 260"C'' and the molten

no lvmer i ss tab leso longasoxygen is r igo rous lyexc luded .Everyi;;J'^['ft;;-;;i"; riett spin-nine' ai in th" .p.olvmerizationil;;,'io-pr"""tt-"i' "oting in-to contact witb the molten

nolvmer.""i l" i l ; spinning buil<' l ing, the chips of polymer-are dried to

r;;;it;;;; of-moittuttl'und the; passe<l.to.storage hoppers'

nri,. irt,j ri"ip"t" iu. chips are fed al required to the spinning

machines." ' i ; i ; ; ; t is carried out in a manner similar to that used for

";;;;i;; nur"t, ttt" n"'oiiitt polvmer being pumped- through

ili#'il; ,pi""Jt.i. a, the filamcnts emersc' thev solidifv and

are woun<l into packages of undrawn yarn'

JJ'+

(,t - Z<trtr.r Lr- It

ujdg

lllJo'F-

?z? {5 >

loFll@+-oll@+loflI t7-1-

=\]|}$]llrlilnlTlri|Nrn i€*--**"'i

oz 67fr

u7 az <z u

.ol

zd

3 3 5

t I A N D D O O K O F T E X T I L E F I B R E S

The undrawn yarn is stretchcd to about l ive t i rnes i ts or iginalIcngth on drarv-twist machines, the stretching being carr ied outusual ly at elevated temperature. I f high tenacity yarn is beingnrade, the filaments are drawn to a higher degree than in thenranufacturc of regular tenacity yarn.

It is normal practice for PET polyester yarns to be drawn hot,as this gives a more uniform product than cold drawing. Thestretching of heavy denier yarns and monofi laments may, how-cver, be carr ied out at room temperature, as the poor heatconduct iv i ty of thc l ibre makes for i rregular i t ies in thick l i lamentswhich are drawn hot.

Sroplc Fibrc

Staple f ibrc is produced by spinning a great nurutrcr of f i larnentsand br inging thenl together to fornr a l reavy tow. This is drawnand then cr inrped nrechanical ly, and the cr inrp is set in the f ibreby heat treatment. The torv is then cut into staple of the desircdlcng th .

PITOCESSING

The basic finishing processcs for 100 per cent PET polyesterfilanrent yarn fabrics may be arranged in the following threesequences :

( l ) Scour - heat-sct - dye(2) Fleat-set - scour - dye(3) Scour - clye - heat-set

Loonr stains and other forms of contaminat ion are di f i icul tto rcmove frorr c loth which has been heat-set, a.nd i t is prefer-able to scour before heat-sett ing. Also, goods which have notbeen heat-set before dyeing wi l l tend to shr ink during dyeing,and the dyed goods will be subjected to high-tenrperatures afterdycing. For these reasons, sequence ( l ) is the most gcneral lyusefu[.

Scquence (2) el inr inatcs a drying process and is sui table forfabrics which are pcr lect ly clean in the loomstate. I t is, however,rarely used for PET polyester fabrics except in the case ofcu rtairr ncts.

l f sequcnco (3) is uscd, sorne st i fTening of the fabric is l ikcly tooccur fol lowing hcat-sctt ing. The degree of st i f lcning depends on

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the construct ion of the fabric and on thc tensions rvhich aredeveloped during sett ing. In othcr rcspccts, thc scqucnce isattract ive, and i t is l inr i ted only by thc fastucss of thc avai lablcdycstuf ls to subl inrat ion under heat-sctt ing condit ions.

Scouring

PET polyester l ibrcs arc suppl ied in a high statc of c lcanl incss,and i t is gcneral ly unnccessary to scour thc ntatcr ial pr ior todycing. If, horvcver, a batch of fibrc should bcconrc so dirty asto require scouring, the bath may be sct with

Water 1,000 partsSodn ash 2 partsDetergent, such as tcxt i le soap,

or Lissapol C, D, NC or ND I prrr t

The tcnrpcrnturc is raised to 70'C. for 15-30 mirrutcs ant l ,al tcr scouring, thc goods should bc r inscd t l roroughly to cl inr inntcal l t races of alkal i . A smal l quant i ty o[ acct ic acid nrty bc addcdto the f inal r i r rsc.

PET polyester goods wi l l of tcn acquirc dir t lnd stains durirrgmanufacture, including aftcr-waxing agcnts rppl ied to sizcd warpyarns, loom stains and othcr forms of soi l ing. I I goods nrcheat-set before removal of thcse stains, subsequent clcaning ofthe goods wi l l become di{ l icul t and perhaps irnpossiblc. I t isprcferable, thercfore to scour goods bcforc heat-sctting. A blthof the fol lowing cornposit ion is comrnonly uscd:

Waterz Soda ash

or caustic soda (llakc)Detergcnt, such as texti le soap,

Lissapol C, D, NC or ND

Fabrics of relatively opcn structure,nrarquiscttes and lerros mry bc scoured in atemperatures below 60'C.

1,000 parts2-3 pa rts0.5 pr rts

l-2 parts

such rs voilcs,shallow winch at

Illcachirtg

Thc nrtural white colour of PET polyeslcr f ibrcs is usunl lysat isfactory for nrost purposcs, and blcnclr ing is unrrcccssrry.Whcn fabrics arc to be f inishcd white a sl ight ly inrprovcd

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colour nray be obtained by bleaching in a bath set with 2-3 partso[ socl ium chlor i tc per 1,000 parts of watcr at pH 3-4. Othercommon blceching agents have l i t t le or no el lect on the colourof PET polycster fibres.

The best results are obtained by making use of f l t rorescentbr ightcning agents. Those used with PET polyester f ibres com-monly havc the fol lowing character ist ics :

(a) A relat ively high dyeing temperature is required. Oneresult of this is that they are virtually non-eflective as additivesin domestic washing powders.

(b) Hieh wet fastness. This ensures l i t t le loss under normalwashing condit ions, obviat ing the need for restorat ion of thewhite during washing.

(c) Lightfastness is high enough for all apparel uses, and inmost cascs is sui table also for furnishings and curtairrs.

Fluorescent br ightening agents are appl ied by the mcthodsuscd in dyeing with disperse dyes, i .e.

(a) Appl icat iorr at the boi l , without carr ier.(b) Appl icat ion at or ncar the boi l , with carr ier.(c) High temperature appl icat ion (130'C.), without carr ier.(d) Application by pad-thernrofix techniques.

The nrethod selected wi l l depend upon the type of machineryavai lable, and the structure of the fabric. Most [abr ics maybe handled on a bcam-dyeing machine at or above 100"C., whi lea j ig may be used for the more stable woven fabrics.

Rope processing in the winch is often used, especial ly for warp-knit ted fabrics. There is some sl ight r isk of rope marking, butthis can usr.ral ly be removed during subsequent stenter ing.

The select ion of a part icular f luorescent br ightener dependsupon the f luorescent tonc and fastness required, and on themethod of appl ica{ ion. The amounts of br ightener and carr ierarc dctcrnr incd by the strcngt lr and ef lcct ivencss of the products,and the nrrnufacturers' instruct ion should be fol lowed.

Most I iuorescent br ightening agcnts sui tablc for PET polyesterf ibres nray be appl ier l f ronr a soditrm chlor i tc blcach l iquor, sothat a onc-stngc clrcnr ical nnd opt ical blcach is possible. Carr iersof the o r tho-phen yl-phc nol c lass nrust not be usc.d. howcver.ei ther during or after chlor i te bleaching.

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Techniques reconrmended for obtaining a good whitc f in ish onPEI polyester and blcnds are out l incd bclow.

100 per cent PET Polyester and pEI' polycstcrlNylon IJIcnls

lI/ or p- kni I t e d F ab ricsAn exccl lcnt white is obtained by trcat ing thc hcat-sct f lbr icwith acidi f ied sodium chlor i tc, fol lowed by t l rc appl icat ion of af luorescent br ightening agent at 130.C., or 100"C. with a corn_pat ible carr ier, on a beam-dyeing machinc.

With most br ightening agents, a goocl whitc can bc obtainc<lby a single-bath mcthod in which the f luorcsccnt br ightcnirrgagent and conrpat iblc carr ier are includcd in Lhc sot l iuru chlor i tcl iquor.

lVcf t-knitted Fubrics

Weft-kni t ted fabrics rnay bc handlcd on thc winch, using sinr i lurtechniques.

Wovett Fabrics

The.beam-dyeing machine is recommcnclccl for blcaching wovcnfabrics. Al ternat ively, the j ig may bc uscd, thc conccntrat ion ofchlor i te bleaching chemicals being increasci by sonrc 20 per ccntto compensate for thc shortcr l iquor.

Pad-Thennofix Applicatiott ot' Fluoresccn! Ilrighttning AgctttPadding and baking the f luorescent br ightening agcnt, withoutcherwical bleaching, is often enrployccl , cspccinl ly lor warp-knit tcdor woven curtain nets. The process is chcaper than thosc dcscr ibc<labove, but the results are usual ly in[cr ior.

.The taking stage may be combined with hcat-sctt ing, ancl l lsowith chemical f in ishing whcre this is carr icd out, providing avery economical f in ishing proccdurc. Thc pa<lding l iquor "on_tains suf l ic ient br ightening agcnt, basc<l on t l ,c ""pr"ssion oIthe mangle, to give the rcquircd tntount on thc fabr. ic. . l - l r isvarics with thc product and the effcct rcquircd, nncl thc nurnu-facturers' instruct ions should bc fol lowccl. No crrr icr is nccdct l ,but a wett ing agcnt nr i ly bc incorporntcd i t dcsircd.

Altcr padding ancl drying, thc fabric is hcrtcd on i l srcnlcraL 220"C. for lG-30 scconds depcnding on thc chl r i rctcr ist ics of

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the stenter. Excessive exposure to high temPerature should beavoided in order to avoid inrpairing the brightening ellect.

PET Polycster lCellulosic Fibre Blcnds

Chemical bleaching should be employed, especial ly when thecellulosic component is cotton. For best results, fluorescentbr ightening agents should also be appl ied for both componentsof the blend.

Several methods of chenrical bleaching may be used, the choicedepending on the result required and the equipment available.Acidified sodium chlorite provides a nrost effective single-stagebleach, and a high white is obtaincd from a chlor i te blcachfollowed by a peroxide bleach.

A good result is also obtaincd from a hypochlor.ite bleachfol lorved by alkal ine hydrogen peroxide. Hypochlor i tc or peroxideused alone as a single stage proccss wi l l g ivc a white st t i tablefor nrany purposes, e.g. as ground for subsecluent dyeing.Processes excluding chlor i te are gcneral ly more suitable forcolour-woven goods.

Depending on the weight and construct ion of the fabric, i trnay be possible to heat-set and then process in rope form attemperatures up to 100'C. without undue r isk of rope marking.Lighter weight fabrics, and those of tight construction generally,must be handled in open rvidth on the bearn machine or jig.

PE1'polyestcr/{ lax blends may be bleached according lo thesegcncral pr inciples, but nrore intcnse trcatntcut is rcquircd.

PET Polycster I lVool Blends

The PET polyester component canuot be bleached with chlorinecompounds in the presence of the wool cotuponent. Chernicalblcaching of PET polyester/wool blends is virtually restrictcd,therefore, to the blcaching of the wool. Hydrogen peroxide isthe preferred agent, and bleaching is carried out after a fluores-cent br ightcning agent has bcen appl icd to the FET polyestcrcomponent. This corrects any yellowing of the wool which mayhave occurred during the application of the ageltt to the PETpolyester f ibrc.

Prc-Sctt ing

Urrset PET polyester filament yarns will shrink when allowed

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to relax in boil iug water, comrnonly by sonrc 7 pcr ccnt. At.130'C., shrinkage is of the ordcr of l0 pcr ccnt.

If unset yarns in package fornr are subjcctcd to any proccss,such as dycin[, involving clevatcd tcnrperaturc, thc shrinkagc wil lbring about consolidation of the packagc. In dycing, this rcstr ictsthc even f low of dye l iquor and causes unlcvcl dycing.

Before dyeing, PET polycstcr filanrent yiuns rrc wound on tocolhpsible paper tubcs and relaxcd for 20 nrinutcs in sirturrtcdsteanr, preferably at a temperature 5'C. highcr than thc uurxinrurrrtemperature which will be reached in thc dycing.

Precautions should always be takcn to cnsurc that condit ionsin the stearning chamber are as unilorm as possiblc. Variation.in the steam sctt ing condit ions can cause vnriatiou in clycirrgproperties, and it is prclerable to steam thc wholc of cach dycingbatch at the same timc.

IIclt-Sclling

Tho purposc of heat-sett ing is to stabi l ize thc fabric to thc cf lcctsof any hcat trcatmcnt which i t nray rcccivc in subscqucnt f in ish-ing processcs, in making-up, or in usc.

' l 'hc sclcct ion of hc:r t-

sett ing condit ions is control lcd, thcreforc, by thc intcndcrl cnd-uscof the fabric and by thc thcrnral history of thc yarus fronr whichit is constructed.

For PET polyester fabr ics, tho heat sett ing tcmpcraturc shotr l t lbc highcr than the tenrperir tures which are to be uscd in plcat i rrg,cnrbossing or calcndcring, so as to cl inr inate thc possibi l i ty ofuncontrolled shr.inkage in thcse proccsscs. It should bc cnrphirsiz-ctlthat the. abi l i ty of PEf polyester f ibre to acccpt. a pcrrnancntset is r iot in l luenced by the temperaturc of pr ior hcat-sctt ing.In this respect, PET polycster fibres difler from sonrc othcrsynthetic fibres.

Steant Sclling

Prcssurc sterming is not rccontnrendcd for thc sctt i r rg of I ' l : ' l 'polycster fabr ics, bccausc of vrr iat ions bctrvccn thc insi t lc nrrt lthe outside of thc batch in thc dcgrccs of shr irrkagc att t l rcstnt intwhich arc produccd.

IIot-Air Sctting

A hot-air stenter is commonly uscd in hcat-sctt ing PDT polycstcr

3 4 1

I r - r r r f t - r - r I r r r r M Il ir i

l l , \ N r ) l l O O K O I : I l i X l ' l L E I i I I I R E S

I ' r l r r n r c r r t [ : r b r i cs . ' l - hc p in s te l l t c r i s us r ra l l y p rc [ c r r cd f o r t l r esc t t i ng o I r vovcn f t r b r i cs , bu t f o r f : r t r r i c s i n r v l r i ch a p in -n ra rkcdsc l vc r l gc i s un : r cccp tub l c , t l r c c l i p s t cn t c r n tay bc uscd i n assoc ia -t i on ' , r , i t h cy l i nc l c r sc t t i ng ( sce be lo rv ) .- l 'hcrc

arc d i l l lcu l t ics associ t r tcd rv i th t l ic contro l o [ rvarpsh r i nkagc i n c l i p s t cn t c r s . ' l ' h c c l i ps t cuc l t o rna rk t hc sc l vcdgcso f t hc c l o th t r nc l c r t hc t cns io r r s wh i ch a re c l cvc lopcd i n hca t -sc t t i r r g , an r l t i g l t t sc l vcc lgcs n l l \ y bc t o rn f r o r r r t hc body o I t hcfabr ic . I -ocal cool ing at t l te sc lveclgcs is a lso nrorc scvcro in thcc l i p t h ; rn i n t l r e p in s ten tc r , and r r ray p roduce rna rkcd un l cvc lnessi r r s r r l ' s c r l r r c n t r l y c i n g .' l ' l ic

h igh dry-heat shr inkagc of l rE ' f polycstcr f i lanrent fabr ic .sncccss i t a t cs accu ra t c con t ro l i n s t c r r t c r i ng i n o rdc r t o avo i c l[ : r b r i c r l i s t o r t i on . ' ] - l r c sc l vcdgcs shou ld be p in i red accu ra te l y ,lv i thout cxccssivc ovcr fccd.

Cy l i t t t l t r Sc t t i r t l i

Cy l i n r l c r o r cy l i r r dc r - t r r r d -b lankc t sc t t i ng n rach incs a rc use r lp r i nc ip ; i l l y i n t l r c s tab i l i za t i o r r o f hcavy i ndus t r i a l PL - ' f po l ycs t c rl ' ab r i cs , ' , vhc rc s t cn t c r s cou l c l r r o t r . v i t hs tand thc l r i gh t cns ionsr lcvc lopct l in sct t ing.

- [ -h is r t rc t l roc l is a lso usccl ' ,v i th [abr ics such

as s : r i l - c l o ths r v l r i c l r r cc lu i r c co r r so l i c l a t i on du r i ng f i r r i s l r i ng . I nco r r j t r nc t i on r v i t h s t c r r t c r i r r g , i t i s l l so usc r l t o ; r ro r l t r cc t l r c cxcc l t -t ional ly r rn i fonrr f i r r ish rv l r ich is rcc l r r i rcc l for I ) l t ' l - po lycstcrb ; r sc f : r b r i cs u ,h i ch : r re t o recc i vc a p las t i c coa t i l l g .

I I cut -S ct t i t tg C ot td i t io t rs

I ) l r - l 'po l l ,cstcr f i lantcnt fabr ics arc col l tn tonly sct by cx1 ' rost r rci o r l 0 J0 scconds i r r t hc I t o t zo t re o f t hc sc t t i ng s t cn t c r .

- l - he

cxtrcrr rcs o l th is^ ra l tgc correspond rv i th l ightwcight fabr ics ofless t l rarr 68 g/ rn2 (2 ot . . lsq.yt l .z) ancl rv i t l t hcavy l -abr ics of up to2 0 3 g / r r r ' ( 6 o z . l y r l . ' ) . ' l ' h e l ' o l l o r v i r r g t a b l c s u t g c s t s s e t t i n gt c rupc ra t t r r es and sh r i nkage a l l o r vanccs su i t ab l c [ o r t l r e f i a tf in ish ing oI a rv ic lc rangc of I r t i - l ' po lycstcr f i larncnt fabr ics:

I:abricClo.r.r

I

')

L Ic thod

I) i ns t cn t c rl ' i r ts t e n t c r

Sct t i t rg Sl t r inkoge' l -cr t rp. ( 'C.) lVorp

2t0-220 3-5

Al lov,ancc (" / " )IVell3-5

3 5200-2 I 0

342

l - 5

l . l l

I:ttbric McllrotlC/rr.r',r'

3a I t ins ten te r

3b l , i ns t cn t c r

4 C l i ps t c l l t c fp l uscyl inc lcr

5 Cy l i ndc r

D : .S } 'N I I I E ' r I C I ; I I } I T I ]S

, S c t r i t t g . < i l t r i r t k t t g t ,' l

c t r rp. ( -C.) l l l t t r l t

r 5 0 , 1 6 0 0

r 50-200 0 5

1 5 0 1 6 0 n

z l I l t tn ' t t r t t ' t ( ' ) ! , )l l ,cl t

0

0 5

0

l;rccI r rcc (15 approx . )

2002t0

l : rc cl 0 : r p1 ; rox

c lu r ' r I i ' c l uc rcs I cno cu r t ^ i ' [ ' b r i cs u r r r s i r r i r . r vc ry o r ) c 's t r t rc t r r rcs.

C lu . r ' s 2 i nc ludcs l l r c l ' ^ j o r i r y o f I r r : ' r ' po rycs t c r f i r . r r r c . t wovc l rf l b r i cs ( t n l l c l ns , t r v i l l s , s r r i i ns , c t c . ) .C luss 3 i r r c l uc l cs co ro r r r - r vovcn fab r i cs . - r - l r c

r r r : r j o r i t y , f f : r b r . i c st t t udc f ron r h igh - t cn r ' c r i r t r r r c o r c ^ r r i c r t r ycc r y r r r i r s , , i c s r , , t , i . . i ut t r . k i ' g - rp ^ r r l t . r r i l d l au r r t r c r i r r g co r r r l i t i . r r s . I ; r r b r i c J r ropc r l i c ss r r ch as h l r r c l l c a r r< l . c r c : r sc r ccovc ry ; r r c , l r owcvc , . ,

' f , . , i " r , , i i y

t t r t r r r ovcd by t l r c r r i r t r sc i l . i r r g t r c ^ t r r r c l ' t s r rggcs tc r r I o r ( _ . rass l : r .I r ab r i cs l r r ac l c f r o r r r ya r r r s r r ycc r by o t l r c r r r r ca ro r r s . r w r r i c l rco ' t a i r r . unsc . t w l r i t e ya r . s f a i l i n to c r . ss 3 [ r , : r r r r r s r ro t r r t r bc l r c l r t -s c t a t t l i e h i g h c s t t c ' r p c r a t r r r c p c r r r r i t t c d b i . t l r c s u b l i r r a t i o . . ft l rc dycstuf ls usccl .

Qlos ' r ' l i .c ludcs fabr ics [or rvr r ich corrprctc ly f rcc srr r i r rkagc isnot pcrnr iss ib lc , but rvr r ich r r t rs t bc f i r r is l rcr r f r .cc f r . r r r p i , , o i ' . r ; i . ,r r t i r rk s .

w l r i ch s l r r i r r kagc i s r l cs i r : r t l l c , s r r c l rI r c : r vy f o r s t cn l c r p roccss i r rg .

Cl t ts . t 5 inc lu i lcs iabr ics inas sa i l c l o t l r s , o r r v l r i ch t r r c t oo

Al t l i t io t ta l F i t t i t l r i t tg o l I Icur-St , t I ;ubr icsI l a r shnc .ss o r ' p l pc r i ncss '

p roc l r r ccd t , y l r c l r t - sc l t r r r g n lay bcrcrrovcd by.srr l ;scqrrc ' t rvct ' roccsr" . , r , , i r r r rs j ig-scorr i i 'g , , i , r . , i . . r . ,g i vc so ' r c n rcc l * r i c i r l ac t i o ' . ' l ' h c r ^ t c o I so f t c r r i . g i s accc l c r ^ r c r lby t hc p rcscncc o f ca r r s l i c so r l ' i r r t l ' , c s .oL , r r , . , g b . t l r . I r ab r i csrvh i ch have bcco r r r c cxccss i vc ry ha rsh sho r l c r [ r c p roccssc r r a t t he

I I A N I ) l l O O K O | I I : X l l l - l : I : l l ] l l l r S

[ r o i i o r r r r r ] cnc losc ( l j i g i n a b l t l r sc t \ v i t l ) 5 l ) i r r t s o f ca r r s t i c so ( l r r( l l r r kc ) pc r I ( ) 0 p l r t s o I w ,u t c r .

- l ' i r c p r occss p r t t t l L r ccs a l oss i nI rLb l i c r vc ig l r t o f t l r c o rdc r o [ 0 . -5 l t c r ccn t .

' l l r c c l l c c t l t r o r l r r cc r l

i s c l L r i l c t l i l l c r cn t f r o r r r t l r l r t o l t l l c convc r r l i ona l ' c l u , l s t i c so ( l i lso f t cn i r ) , l l ' l ) r occss i n r vh i ch 6 -10 pc r ccn t o I t hc I ab r i c r vc igh t i sI o s t .

I ) ; c ing

l ' l ' . l ' po l l , cs t c r f i b r cs a rc hy ( l r o l ) hob i c , and r l yc ings o I r r sc fu lt l cp t l r r u c ob t l i r r c t l by r r s i ng thosc c lusscs o I t l y cs t r r f l s r v l r i c l r a r csubs t r rn t i l l l y i r r so l t r b l c r ' n r va t c r . ' l - hcse i nc lu r l c t hc r l i spc rsc r l yc -stu l l .s , i rz-o ic c lvcstu l ls (appl icc l by a nrodi l icr l tcchniquc) , ancl al i r r r i t c t l r r r r r nbc r o I va t r l y cs .

Disyrcrsc t l l ,cstuf l 's prov ic lc brr i l t l -u1t and colorr r fastncss that isar lcr luatc fo l r r rost puf l )oscs, ancl u r . r , i r lc rangc of co lours is avai l -i rb lc . Az,o ic dy 'cst t r f ls proc l r rcc r r r iurgc oI br ig l r t rcr ls urr t l l ) l l roons,: r b l ack anc l i r nav l , b l t r c , l r l l o I r v l r i ch h i r vc good fus t r r css t o scvc rcrvash i r r -q . ' l ' l r c r r sc f t r l r r css o f l l r c i r zo i c r cc l s an r l r nu roons i s l i r t r i t c r l ,I t o r vcvc r , by t l t c i r t c r r t l c t r cy t o bc t l u l l c c l i r n t l t o l osc r r rbb i r rgl i r s t r r css a f t c r s t c l n r - sc t t i ng o r hca t - sc t t i ng l ) r occsscs -

V l t r l y cs t r r f l s ) , i c l c l a l i n r i t cd range o f shudcs , onc o r t r vo o [r v l r i ch a rc vc ry b r i gh t , bu t t hcy bu i l d up to on l y u t cd iun r dcp ths .

l ) l r . l ' po l ! ' c s t c r f l b r cs l r : r vc ; r l r i g l r a f i i r r i t y [ o r < l i spc rsc t l y cs t r r f l ' s ,b r r l t hc r l t c o f r l i l l . L t s i on o I t hcsc dycs t t r l l s i n t l r c l i b r c i s r c l : r t i v c l yl ow , . ' l ' h c r l t c o f r l y c i r rg n ray bc ra i scc l t o a co r r r r r r c r c i a l l y acccp t -: r b l c l cvc l c i t l r c l by r vc l r k i r r g r r t t l r c bo i l i r r t l r c l . r l c scncc o f l r rr t ccc l c ra t i r r g i t gcn t o r ca l l i c r , o r by r l i , c i r r g unc l c r supc ra tn ros l t l r c r i cl ) r css r r r c a t l c r r rpc r i r t u r cs i n t he r cg ion o f 130 'C . ' l - hc h igh t c l r r -pc ra t r r r c r l l , c i r r g l t r c t l t o r l i s p r c l c r ' : r b l c a r r c l s l r ou l t l bc r r scc l r v l r c r cposs iL r l c , i r r o r c l c r t o t akc t r t l v l r r r t agc o f t l r c cxcc l l cn t l c vc l l i r r gac t i o r r ob t l i n : rL r l c u r r r l c r t l r csc conc l i t i o r r s . ' l ' h i s t cchn i c l uc a l soavoids t l rc ac lvcrsc cf lcct of ccr ta in carr icrs o l l thc l ight fastncssof sorr re t l l ,cst r r l Is .

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p rob l c rns cncou r r t c r c t l i n r l yc i r rg t hcsc b l c r r t l s a r c s i r ) r i l l r r l othosc o I P [ r ' l ' po l ycs t c r / r . voo l b l c .ds . D i spc r . sc r r ycs r v i i l r r s t r r r l l ys t l i n s i l k ; r p p r c c i i r b l y , b t r t t l r c s t n i r r r n l y [ r c c l c r r r . c t l r r r r r l t l r c s i l kr l yc r l i . a scco r r t l b l r l r .

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o I v . t r l y cs r r cccss i t : t t cs ^ t r ' o -b t r t h p roccss , b t r t i tg i vcs t l r c bcs t co lo r r r - f i r s l r r css p ro l r c r t i c s . I ) r oc io r r r l y cs t t r f l s l l s c rr c t l r r i r c a t r vo -ba th l ) r occss , : rn r l g i vc goo r l co lo r r r f as tncss t 0gs1 l l c rr v i l h b r i g l r t , c l ca r s l l r c l cs . sc l cc t cc l r l i r cc t co i l on r l ycs {u l l s n i l y [ , cl upp l i cc l f r o r r r t l r c san rc ba lh as c l i spc rsc r l ycs , [ r t r t l n : r I t c r t r cu t -t t t cn I i s nccc l cc l t o co r r f c r r c l so r rab l c r vc t l r r s tncss . Evc r r r v l r c r r u [ l c r -t r c . t cd , c l i r cc t co t l on < l ycs l r r fTs a rc s l t i s [ ; r c to ry o r r l y t o r l i 13 l r ts l x r r l cs , cxcc l ) t i n t hosc cnc l - r r scs r v l r c r c ga r r r r c l r t s i r r c r v : r s l r cdi r r l r cq t r c n t I y .

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r r r c thoc l s a rc co r r r . r o r r l l , r r scd fo r t l r c [ i xa l i on o [ | , r . i r r t c t lco louls on to I r l j - l ' po lycstcr . Iu t r r . ics:(a ) P ro lo rgcc l s t ca r r r i r r g ( l - 2 ho r r r s ) a t . t r r r osphc r i c p rcss r r r c ,

us i r rg a ca r r i c r t o p ro r r ro t c c l ycs t r r l l r r r i g r : r t i o t r .( ( b ) s t can r i r r g f o r 20 -30 r r r i r r u t c - s i ' a h igh p rcss t r r c s t r r r - f . r r r r cs t ca r r c r , us i r r I l r i r l r - t c l l l l ) c ra tu rc s t ca r r r ( | . , 1_ .2 .0 kg / c r r r2 ; 20 2 f ]I b / i r r 2 ) .

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r rsc of such a proccss on l ) l l - f po lycstcr /cc l lLr los ic f ibrc b lcnosrvorr lc l , l rorvcvcr , s t r ip the c lyest t r [ I f ronr t l ic ce l lu los ic cornpor. rcnt .I t i s c s s c n t i a l , t h c r c f o r c , t h a t t h c ' s o l p i n g ' a n d r i n s i r r g t r c a t n r c n t ssho r r l t l bc r l a r l c as i n tens i vc as poss ib l c . T l r c use o f a goodl r ro r l c rn soup i r rg and r i ns ing rangc , f i t t c c l r v i t h sy t ray p ipcs a r r r lt l c v i ccs I ' o r i n r l uc ing tu rbu l cnce i n t l r c soap i r rg l i c l uo rs , i s r ccon r -tncnr lcc l .

W h c n ' s o a p i n g ' a n t l r i r r s i n g l r r c c l l r i c d o u t i n r o p e f o r n r o n arv inch , ' soap ing ' s l i ou ld con t i r r ue [o r a t l c l s t 10 n r i nu t cs . D i s l l e r sc /r c l c t i vc l l r i n t s shou l r l p r c f c rab l y r ccc i vc a r vash ing -o [ [ [ r ca t rncn tr v i t h a r r r i . r t r r r c o f a non - i on i c r l c t c rgcn t and l r o l yv iny l py r ro l i c l onep r i o r t o t h c ' s o a p i n g ' p r o c c s s .

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i . r pc r [ cc t i o ' s r v i l l s l r o r v ' spoo r co lou r fas tncss , poo r c l yc pcnc t ra t i on , s t r caky o r uncvcndyc i . g , shud i ' g f r o r r r sc l vcc lgc - to -sc l vc r l gc o r c r r r l - t o - c r r t l . r l v cspo ts , ca r r i c r . spo ts , o r r cs i s t spo l s . ' l - l r c causcs o f s r r c l r p r c l l l l c r r i s ,r l i s cou r r t i r r g r r rach i r r c [ a i l u r c , n ray t r s ru r l l y bc t r l c c r l t o onc o ro thc r o [ t hc I o l l o r v i r r g :

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2 . I ; au l t y e r r . r L r l s i f i ca t i o r r o f ca r r i c r o r i ns r r l l l c i cn t c i r c r r l u l i o r r . rr l i s t r i bu t i on o [ ca r r i c r i n t l r c c l yc ba th and th ro t rgh l l b r c o r f r r b r i c .

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t o t l r c d y c b ; r t h .

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t o a l t y o f t h c u s u a l b l c a c h i n g n g c n t s , i n c l t r d i n g t l t o s c b a s c t l o r t

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t c r c i l i n n o r r n a l t c x t i l c u s c . ' l ' h c o n l y c h c n r i c a l s r v h i c h , a s : r

c l a s s , r v i l l c l i s s o l v c ' - l ' c r 1 , l c n c ' f l b r c a t t t o r t t t ; t l o r t t t o t l c r r t t c t c t t l -

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c r r r p l o y ' c t l .l L c s i s t a n c c t o d i l u t c [ o r r r r s o I p l r c r l o l , s t l c l t l t s c t c o s o t c I r o t t t

w o o c l t a r , i s g o o r [ a l n o r n r a l t c t ) l p c r a t t l r c s . C r c o s o t c l l l c s c l v l t t i v c s

a r c n o t l i a b l e t o c a t t s c s c r i o t t s c l a t r t a g c t o ' [ ' c r y l c n c ' '

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s t c a n r i t r c o t r t a c I r v i t l r ' - l ' c r y l c n c ' .Pcrsp i ra t ion c locs no I h : rvc any c lc lc tc r ious c l l cc t on ' ' f c ry lcnc ' .

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t h c p o l y c t h y l c n c t c r c p h t h a l a t c , b t t t t h c c l T c c t s n r c n o t t l t c s l t r t l c

i n c u c h c a s c .U r r t l c r t l r c i l f l r r c r r c c o I i r c i r l , g r l t t l t r l r l t l c g r l t t l r t t i t : r t t t t l ' t l r c f i I r c

r v i l l O c c u r t o a n c x t c r r t c l c l t c n r l c r t t o l t I l t c S c v c r i t y t l I t l t c c o t t -

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g L o r l r : c s i s t a n c c t o t l t c r n u j o r i t y o I r t t i r r c l : r l l t t t t l o t g l t t t i c l r c i c l s i s

a c h a r a c t c r i s t i c p r o p c r t y o [ ' ' l - c r y l c n c ' I i b r c .

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a n c l i l s d c r i v a t i v c s ) i s f t r r t c l u t r r c r t t l l l y t l i l l c r c r r t f r o r l t t l t l r t o I r v n t c r ,

a c i c l s a n r l a r n r n r t r r i n l r n d i t s r l c r i v n t i v c s . I r l t l r c [ o r t t l c r c l t s c ,

p r o g r c s s i v c s o l U t i o n o I t l r c f i [ t r c o c c t t r s , r v l t c r c l t s i r r t l r c I l t t t c r

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r c s i s t n n c e o [ ' ' l ' c r y l c n c ' f i t r r c t o t l k l r l i s i s t t r l l y s i l t i s f l c t o r y

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c t r i o r r r s . O r r t l r c o t l r c r l l r n c l , ' ' l ' c r 1 ' l c n c ' s h o t r l d I t o t b c l ) r c s s t l r ck i c r b o i l c c l i r r t l r c 1 . l r c s c u c c o f a l k a l i s , a s t h c s e c o r t c l i t i o r t s f l t v o t t t '

a r r u c c c l c n t t c t l l t t r r c k c l n t h c f i b l c .

I ' . l l cc t o I Org : t r t i c So lvcn ls' l - c r y l c n c ' p o l 1 ' c s t c r f l b r c s l r o r v s l r i g l r r c s i s t a r t c c t o t t t o s t o l ' t h cc o n l n l o r ' r o r g u r r i c s o l v c t t t s . l i x a r r r p l c s o [ t l t c s c , r v l r i c h i n c l t r t l c t l r ci r g c n t s r r o r r n a l l l , t r s c c [ [ o r c l r y c l c a n i n g , a r c i l s l o l l c l w s : a c c t o r t c ,t l i o x u r r c , c t l r c r , l r t c t l t y l l r t t l c t h l ' l a l c o h o l , b c t r z c t t c , t o l t t c t t c , x y l c r t c ,l i g l r t p c t r o l c r r n r , t r t c t l t y l c r r c c l t l o r i d c , c l r l o r o f o r t t r , c r t r b o t r t c t r a -c l r l o r i d c , p c r c l r l o r o c t l r l ' l c t t c u r t r l t r i c l r l o r o c t l r y l c n c . A t r o o r l ) t c n l -p c n r t t r r c , t h c s c l r a v c l i t t l c c f l ' c c t o n t l t c s t r c r r g t h o [ ' l - c r y l c n c ' .

( l o r r t i n t r o u s i r r r r u c r s i o n I o r 6 r n o n t l r s i n n r c t h y l l l c o l r o l a t 3 0 " C .

c i r u s c s n c g l i g i b l c l o s s o f t c t t i r c i t y , r v h i l c a l 5 0 " C . r c c l t r c t i o n i s o l

t l r c o r d c r o f l 5 l l c r c c n t .- [ 'hc

t rca tnrc r t t o I unsc t fo r r t t s o [ ' ' l ' c r1 ' l c r tc ' , s t tc l t l t s t r r r [ in is l rc t lf i l r r r r r c r r t y : t r r t , i r r s o l v c t t t s l n i t y c i r u s c a l r p r c c i : r b l c s h r i r t k a g c . W i t l rl r r c t h y l c n c c h l o r i c l c u n < l c l t l o r o f o r r r r , t l r i s r v i l l o c c u r c v c n i I t r o o n lt c n r p c n r t u r c , a n c l r v i t h r t u r t t y o I t l r c o t l r c r s o l v c t t t s t t t c t t t i c l t t c c lr u t r o v c , s l r r i n k l r g c i s c o n s i t l c n t b l c : r t t h c i r i r r t l i v i t l t r l l b o i l i n g p o i n t s .

S o l v c r r t s c a t r s i r r g t l r c g r c l t c s t s h l i r r k : r g c a r c b c l t z c t t c , I o l t t c t t c ,

x y l c n c , t l i o x a r t c : u r r l l h c c l t l o r i n l t c c l s o l v c t t t s r v i t h t h c c x c c l . r t i o t t

o 1 ' c a r [ r o n t c t r a c i r l o r i d c , r v l r i c l i c a t r s c s I r o s l r r i r r k a g c . ( ] i r r c t t t t t s l b e

t : r k c r r , t l r c r c [ o r c , t o c n s u r c t l r l t t r t t y s t r c h ' - l - c l 1 ' l c l t c ' y i i r t l s o rf : r b r i c s r v h i c h u l c t o b c c x p o s c c l t o h o t s o l v c n t s h l v c p r c v i o u s l y

b c e n l r c a t - s c t .' l ' h c

r a n g c o f c h c r n i c a l s r v h i c l r r v i l l c l i s s o l v c ' - [ - c r y l c r r c ' p o l y c s t c r

f i b r c l t t r o n n a l o r t r t o t l c r ' : t t c t c r r r l ) c r l t t t t r c s i s l i r r r i l e t l , : r n t l t l l c o n l y

c h c n r i c : r l s r v h i c h a s a c l r t s s " v i l I d o t l r i s a r c p l t c n o l s . N I o s t p h c r t o l s

r v i l l s r v c l l o r r l i s s o l v e ' . 1 ' c r y l c n c ' , t l c p c r r c l i n g o n t l r e t c t l ) p c r a t t l r er u r r r l c o r r c c n t n r t i o n t t s c c l . S o l r r t i o l r i s t t o t r t c c o t t l p t r n i c t l b y i r t t t t t c -

< l i r r t c t J c g r l r l i r t i o r r , a n c l t l r c v i s c o s i t y o f i r s o l t r t i o n o [ ' ' l ' c r y l c r r c '

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r v c i g l r t o I t h c p o l y c s t c r .' ' l ' c r y l c n c ' r v i l I a l s o c l i s s o l v c i t t t . t . t o t t o - , d i - , a r t d t r i - c l r l o r o a c c t i c

l c i d . ' l

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t l r c i r n r c l t i n g y r o i n t s , t v l r i c h a r c r c s p c c t i v c l y 6 l ' C ' . , l 0 ' C . a t l c l

. 5 5 " C .S o r n c o t l t c r s t t b s t a t t c c s t v i l l t l i s s o l v c ' ' [ ' c r t ' l c r t c ' l r t l r i g h c r

l c l r l ) c r i r l u f c s , s o l t r t i o r r b c i r r g r a p i d i n t l r c b o i l i r r g s o l v c t t t . A t l r o l l g

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i s v i r t r r ^ i l ; , u r : r r i ' c c r c t r l r y t l i r r r c r l r y r p r r r l r . r : r r c l r t' o a r * l I c r r p c * t t r . c s . I ) i c l r l o ' . r l i i l t r o r - a r r c t r l r r c ( . A r c t o r r , ( r , r' l r r c o r ' l 2 ) a r r d . r , r o c r r r o r o r r i f l r r o r o . r c r r r r r r r c ( , A r . c r . r r , . r o r' l ; r ' c . r r ' 22 ) , ' s

co r r r r r r . r r . l y r r sc t l i r r r c f ' r . i gc r . r r r ro r r L r r r i t s t l . r r . I u l l c c r' l - c r y l c l c ' t o uny r ro l i ccab l c t l cg rcc l l I t c l l l l ) c r ; r t r l r cs l r c t r vcc r r- 20 "C . : r r r d . t 20 " ( . ' .l { cs i s t ; r ncc o [ . l ' c r1 , l cnc '

t o l r y r l r oc r r r . t r o r r o i l s i s 13oo t l .

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h i g h r c s i s t i v i t y i s I r r u i r r t r r i r t e c l a t h i g h I r t r l r r i c l i t i c s .

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r c r n a i n s t r i g h . A t 1 8 0 " C . , f o r e x a n t p l c , i t i s a b o u t 3 x l 0 t 2 o l t t t t - c t r l '

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p r o r l u c c a c o r t t l t t c t i v e t r a c k .

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t i o n t o t h c s k i n .

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y a r n l r r t r l l h c r r t a t t s r r r [ a c e . ' l ' l r c r l y n a r r r i c c o c l l i c i e r r l o f f r i c t i o l l

o f ' - l ' c r y l e r r e ' f i l a n r c n t 1 ' l t r t t e g e i l t s t a t t l l t t t s t c c l s t l r [ a c e , [ o r

c x a r n p l c , i s t t t u c h l o r v c r t h a t r t h a t a g a i n s t L r r i g l r t s t c c l .

W i t h s t : r p l c I i b r c , l r o r v c v c r , I r i g h I r i c t i o n a l c o - c l l i c i c n t s b c t w c c l t

s l ) L r n y u n l s a n t l g t r i r l c s a r c I l o t o b t l i t t c t l . ' l

l r i s i s c l u c t o t l r c

a r r a n g c n ) e n t o I t h c i n c l i v i d t l : r l [ i b r c s i r t t l l c y a r n b c i r l g s t r c h t h a t

in t in ra te contac t bc t rvcc t r the yarn and t l l c gu idc s r r r [acc t locs

n o t o c c t t r .

I l c f rac( ivc I l r t l cx (20 'C. )

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l ) l l ' l ' I )O l .YF-S ' I 'F . l { F I I l l t l i s IN USI I

( l cncr : r l Ch l r r rc lc r i s ( i cs

iY f a t ' l t t t r t i c rt l I ' ro pc r t i t s

C o r t s i t i c r c t l s t r p c r l i c i r r l l y , I ' l i ' l ' p o l y c s l c r

s i r r r i l a r i n t h c i r t n c c l i a r t i c a l p r o p c r t i c s t o

I r rg l r - s t r cng th f i b r cs r v l r i ch c l i sp luy a , cx t c r ) s i r r r ; r [ [ ; r c i r k t r r : r tr c l l c c t s . g r ca t t o rg l l . css . - t L r t o ' - r ook i r r l l r r . r c c rosc ry : r t t l r cr rc-c 'a ' icaI pro l rcr t ics of t^c t rvo typc:s oI l ibrc, i " . r1rurr" ' , l id i f lercnces nray bc sccn.

Most s igr i f ica ' t o [ t l rc cr i f lc rcrrccs r rc t rvccrr I ) r : r ' por l ,cstcr ^r r t lny lo^ f i b r cs l i c s i r t r r c i ' i t i a l r ' o r ru r i . I ) r r ' r ' po rycs rc r r i t r r . . , r , , , u .a h ighc r i n i t i a l r nodu lus t r r a r ny lon I i b r cs . ' r r r i i r r r cu ' s r t r , , t i l t , ipo l ycs t c r I i b r cs l r avc a g rc . t c r r cs i s tu ' cc t o s t r c r . c r r i r g i , r , . r 1 ruu . .t o a t c r r s i l c f o r cc . ' f l r c app l i ca t i on o I a sn ra i l l o . r l r v i i l . , , , , r . 2

o r 3 t i l r r c s a s g r e a t a ' c x t c ' s i o ' i ' n y l o . a s i ' l , I l . l . f , . l 1 , . l . f{ i b rc.

l ' h i s h igh r cs i s tancc 1o dc fo r ' r a t i o r r c r i sp r ^yc r r by I ,E I ' po rycs rc rf i b res i s shown a l s . i . t l r c i r h i gh r " s i r t , , , , . . t o bc ' r l i ' g . I , l : . 1 .polycstcr f ibrcs arc l t ruch st i f l -cr than ny lon l ibrcs.- I ' he

h igh r ' oc l r r l us a .d s t i r l , c ss o f I r r i - r ' po l ycs t c r [ i b r cs co r r f c rg r c a I c l i r r c n s i o . a l s t a b i r i t y o n [ . b r i . . , r , , , i " f r , r , r r r c r r r . ( i o o r r sco r r t . . i r i ' g l ) l i - r ' po rycs t c r f i b r cs l r r c . . I r c ; r t r i r y , t . t ' u , , , , . , r . : t

r , . , ] . ii s a ch . rac t c r i s t i c f i r r r r ' c ss t o I r L - r ' po rycs t c r f : r l l r i c s , * t . , i . r , , i l . j r r , , yI r cnspc r hand l c t l r t n t hosc o f nv lon .' l ' he s t i l l ' c ss o i PE ' r ' po rycs l c r I i b r cs . r r y [ r c r r c r r ro r r s r r - : r t c t r by

. : : ] ] ] l l , l i i r ,g . PE-t '

,no lycsrcr t ibrcs , ,v i rh ivool of conrpar : r t r tc( l r : ' ' c t c r . A ' 1 . ' l r r t c x ( ' 1 t r c r r ) l ' i b r c , f i r r c . r l r r r P l c , , , t , r i , " r ' , i i . i ,i 9 : ] t

i s , c t . ' ' Pa r , l ; l t ' i r r r l i u r ' c t c r r v i t l r a 70s ' r v ,o l

( 2d ; j . - ; i ;r i l ' ( t c , r l o w c v c r , i s r r o r c l i l < c t l r a t o 1 - l r ( r . l s r v . t l l ( r l i . r r r c t c r1 r \

S Y N - T I I I I ' I C I : I I ] I I I ] S

co t t o l l w i l l p rov i< l c a c r i spc r l l r n t l l co I con r l t : r r : r b l c r l i t r r r r c t c r . ; t l r c i r r i t i u ls taplc I ibrc is lorvcr t l r t r r r th l t t . l f

C )n t hc o t l r c r l r and , I f i ncthan a I r t j . l - po lycstcr I ibrcrnodulus oI l ) [ , - f po lyestcrc o [ [ o l t .

( i b r c s r l r cn y l o n { r b r c s .

g c r r c r l l l yl - l i cy a t ' c

- l ' l r csc cha rac t c r i s t i cs o f h i gh s t r c r rg t r r , r r i 13 l r r cs i s t . r r cc t o s t r c r c l r ,t o t rgh rcss and s t i rT ' css a re o I i ncs r i r r ab rJ v^ r r r c i ' , . , , , , , , f t i . i . t ,o f . t cx t i l e app l i ca t i o ' . - f ' c y

co r r f c r g r ca t t r i r r c r r s i o r r , r s i . b i t i t fand co . t r i bu t c t o t hc c r c r r sc - r cs i s t ^ . cc -u r r , l s l r r pc - r c l c ' t i o r r r v l r i c l ra r c . such i r npo r ta r r t f ca tu res o f P l l ' r ' y ro rycs t c r 1 ;oo t r s . r ] u t t l r cyt t r i l i t a t c aga i ' s t t l r c r r sc o f I 'E I ' po l ycs i c r i i b r " s i , r so r r c : r p l r r i c ;1 -t i o n s ' J ' l a d i e s ' s t o c k i r r g s , f o r c x a n r l r l c , i t r s c s s c r r t i r r l t r r . t r l r cf i b r c sho r r l d l r avc s r r f hc i cn t ' g i vc ' t o : r cco r r r r ro t l ; r t c r r r c s r r c l c r r i ugt h a t t a k c s p l . c c a t t l r c k ' c c . ' r ' h c f i b r c r r r t r s t . r s o l r : r v c s u r r i c i c r r tc l as t i c r . ccovc ry f r o r r r sL rc l r s t r c r c r r i r g t o . c ( r r r r t u i t s o r i g i r r r r ls l r u l t c r v l r cn l l r c k r r cc i s s l r l i g l r t c r r c t l .

Ny lo r r , r v i t h i t s l o r v i r r i t i . i n rod r r r t r s . rd r r i gh c r l r s t i c r ccovc ' r , .

l 6 l

I I A N D I I O O K O F ' l

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i s n c l r r r i r a b l c f o r t h i s c n c l - r r s c . I l L r t l ) l t - f p o l l ' c s t c r f i b r c , r v i t h i t s

l t i g l r r c s i s t u n c c t o s t r c t c h : r n d l o r v c t ' c l a s t i c r c c o v c r l ' , i s l c s s s : r t i s -

f r r c t o r y .

A t t h c l o r v c x t c n s i o n s t o r v h i c h , p l l r t i i r l l y l l c c a t t s c o i t h c i r

h i g l r r r r o d L r l t t s , t l r c y : l r e t t l o s t s t r b j c c t i t t t t s c , I ' l i ' l ' p o l y c s t c r y l l r l l s

l r n d f l b r . c s c x l r i b i t r r c g l i g i b l c c r c c l l . I : i l a l l l c l l t y : l r l ) s r c c o v c r c o l ) l -

p l c t c l y , f o r c x l t t t l t l c , f r o l t l l t r t c x t c t l s i t l t t o I l l l c r c c t t t , l t n t l

i . . o u " r y i s ' r o r c t S a n 9 0 p c r c c l l t c o r ' ' l c t c a l t c r ^ 3 ' c r c c t l I

cx tc r rs ion . - l ' hc

rccovery f igurcs [o r s t l tp lc { ib re a rc lo rvcr t l t i t t r

t l r o s c I o r f i l l r r r c n t y u r n s , r l u c t o t l l c p i r r t i l r l l y t t t l t t - r c c g v c r l t b l c

r c r n o v l r l o I c r i t n p f r o n l s t a l l l e f i b r c t l t r r i l l g l o l c l i r r g '

I r l t ' l ' po lycs tc r f ib rc posscsscs an i rn t l l l c i t t r to t l t r t o I dc laycd

c l l l s t i c c lc [o r r r ] l t t ion to p rov i r l c 'g ivc ' t t r t c lc r s l lock- load ing conc l i -

t i o n s . N c v c r t l t c l c s s i t a l s o i l i s l t l a y s n h i g l l c l c g r c c o I s l l r i n g i n c s s

t u n c l c r l c s s r a l t i t l l g a t l i r r g c o n t l i t i o r l s . ' l

l r i s h i g l r i p t t t t c c l i n t c c l a s t i c

rccovcry o I l , l t t ' l to lycs tc r l ib re cx l t l l i ns t l rc good wr ink lc pcr -

f o r n r a n c c i n t v c a r o f f a b r i c s c o n t a i n i n g l r r g l r l l r o p o r t i o n s o f I ' E - l '

p o l y c s t c r h b r c . A l ' t c r h a v i n g b c c n s t r b j c c t c i l t o t l l c b c n c l i r r g

c lc lo r r i la t ions rvh ic l r fabr ics u r tdcrgo i t t t t sc , l ' l - ' l ' po lycs tc r I ib rcs

r c c o v c r c l t r i c k l y t o t h c i r o r i g i r l a l c o r t f i g t t r l t t i o n '

In con l l r . ro r r rv i th o thcr tcx t i l c f ib rcs , I ) l J ' l ' po lycs tc r I lb rc has

lo rv shcur s { rc r r l i l l r bccausc o f i t s non- iso t rop ic n i r t t t rc . As PI ] , ' l -

po lycs tc r i s no t , horvcvcr , a b r i t t l c f ib rc , h igh s l tcar -s t rcss co t r -

ccn i ra t io ls c iy lno t bc sc t up bccat tsc t Ic f ib rc o r y r t r l l r v i l l dc [o r t l t

: rn r l convcr t t l r csc to l cns i le fo rccs . I ro r th is rc r rso t l , thc loop

s t r c n g t h o f l r t j ' l ' p o l y c s t c r f i b r c i s n o I a p p r c c i a b l y l c s s t l t a n t l l c

s t r a i g h t t e n s i l e s t r e n g t l l .

I t Ioisl t tr t :

I rE ' � l - po l ' , cs tc r f ib rcs havc a vcry lo rv r r ro is t t t rc : tbsorbc t tcy , a t rc l

th is a l l c i t s thc p rac t ica l usc o I thc f ib rc in a t r r t t t tbc r o I rvays .' l ' he

n rcch l ln ica l p ropcr t i cs o f thc f ' rb rc , fo r cxa t l lp lc , a rc v i r tu l I l l y

r u r r : r I I c c t c r l b y u t o i s t u r c , t l r c t c n s i l c s t r c r r g t l r n t i d c l o r l g : t t i o t t

rc r r ] l l i n i r rg unchur rgcc l . l r l J l ' po lycs tc r [ lb r i cs l tavc goo i l t l i t r l c l t -

s i o n a l s t t b i l i t y c l t r r i l r g r v c t l l r o c c s s i r r g a n d r v l s l t i l t g '' f h c

l o r v r n o i s t t r r c a b s o r b c t l c l ' t l r l l k c s f o r r a p i d < l r y i n g , a n d

I r l i ' f po lycs ter [abr ics have cxcc l len t easc-o [ -c l rc p ro |c r t i cs .

I n c o n r r r r o n r v i t h o t h c r h y c l r o p h o b i c t l b r c s , l ' l r - f p o l y c s t c r t c r l t l s

t o a c c t t t t t t t l a t c c l t l r g c s o f s t a t i c c l c c t r i c i t y , : t t t t l t h c s c n l a y l ) r o v c

t r o u b l c s o r n c i n p r o c c s s i n g a n d d u r i n g f l l b r i c t r s c . G l I r t t t c t l t s l t t a y

3 6.r

I l : . S Y N I ' l t t : I l C F I I I R F . S

i r t t r r c I c l t r s t . ' r l c l i r t , bcco r r r i r g so i l cc l r r r o r c r . c : r r l i l y t l r : r l r ̂ f i b r ctha t t l ocs . o t so r c l r c r i r y acc lu i r c c r cc r ros r l r t r c c l r r r r gcs . ' r

r r i sd i l l i c L r l t y ' r i r y b c o v c r c o . l c b y t h c a p p l i c , t i o r r o I l t ' t i s t r r ( i cf i r r i shcs , o I r v l r i c l i a ' t r r r r bc r o f r vush .b l c t y l ) cs i r r c r ro rv . v . i l r r b l c .

I r i b r c s o I l o r v ' r o i s t u r c ̂ b s o r 1 . , t i o ' t c r r i l t . b c u r s r r t i s f . c t u r yfo r usc i r r r r ' r l c r r vcu r ' r r d o t l r c r ga r r r r c . t s i ' co r t ^c t r v i t l r t l r csk i r r . ' l ' l r c y c l o ro t abso rb t hc pc rsp i r ^ t i o r r as r v ' ' 1 , [ . r cx . r r rp lg ,r l ocs , . . r l t l r cy r r r . y l ' c c l c l r r r r r p ^ r r t l c l . r r r r r y . ' l ' l r i s i s r r r i t i g . t c r i t .son rc cx t c r t i . t l r c casc o l l , I l ' po l ycs t c r f ab r - i cs , r r s t l i c f i b r csl c r r r l t o ' r v i c k ' r c a r l i l y . l t 4 o i s t r r r c i s c : r r r i c t l r r r p i d l y t l r r . r r g l r t l r cf l r b r i cs , so t l r u t i t c : r r cv : r J r r l r . t c t l t r i c k l y i r s i t ' c . i l r cs t l r c o r r c rs r r r I i r cc .' l ' h c

l o r v rno i s t t r r c pcne t r l b i l i r y o I l , l i ' l ' po l ycs t c r [ i t r r cs c l t r sc r lco ' s i r l c r : r b l c < l i l l i c r r l t y . i r t hc r r cvc lop ' r c r r t o i t l y c i r r g t cc l r r r i r l r r c *fo r . t h i s f i b r c . I 'E ' l ' po l ycs t c r f i b r cs i r r c ' o r v dycc r co r r r r r r t l r r r y u rh igh t cn rpc r l t u r cs , l nd c l f t cn undc r p rcss t r r c .' l '

l ttrrrtol I 'ropcrtics

I r r c . r r r r . r r r v i t l r . t l r c r { l r c r r r r . p r u s t i c f i b r c s , I ) l : ' l ' p o l y c s r c r f i l r r c sr v i l l s o l t c r r r v h c r r r r c : r t c t r . - r ' l r c

s t i c k i r r g l r r r r r r r r c l t i . l S p ' i r t s . It hcsc f i b r cs a rc , l r o r vcvc r , r r i g r r c r ro t rg l r f o r a i l r r o r . r r r : r r ' i c x t i r . , , r . i r ,: u r c l no c l i l l i c t r l t i c s a rc cxpc r . i c r r cc t l i n l l t i s r cspcc t .

I ' � l : . ' l ' po l1 ' cs t c r f l b r cs h l vc a r r cxcc l l c r r t r cs i s r ; u r cc t o r l r c c f l - cc to I y r ro lo l rgc t l cxpos r r r c a t c l cv r r l c t l I c l l r l ) cm l l r r cs bc l c l r v t l r c so f l c r r_i r r g p o i . t , . r r d t l r i s c l r i r r . c t c r i s r i c i s p r . o v i . g i r r p o r t l r r r t i , , , . , , r , , yi r r t l t l s t r i l r I t r IP I i c l r t i o r r s .

I ' l l ' l - po l ycs t c r y ^ r ' ' s ^s supp r i cd by t hc r r r ; r r r r r f r r c tu rc r r r r cr r s .a l l y l r c i r t scns i t i v c i r r t l r . t t l r cy r v i l L sh r . i r r k r v l r c , l r c . t cd i .r va l c r . r r r i r . I f r r cccss . r ' 1 , , I ) r . 1 r ' p ' r ycs t c r r r r l r t c r i u r s r r ' r y [ r cs tab i l i z cc l t o hc : r t . o r r c r r c t r roc r i . s t o s l r r i ' k t o s t r rb l c r r i r r r c . i i . r r sc i t l r c r by s t c ; r . r i ' g c l r by sub j cc t i r g t o c l r y l r c . t r r r r r r c r - co r r t l i t i . r r sr v l r i c l r l l l o r v f r c c r c l l x : r t i o r r .- l ' hc

r r c t l r o r l o I hc : r t r c ra . ru t i o ' , r r o r , , , cvc r , co r r f c r s i r r c r c^sc r lcx t c r r s i b i l i t y , a r r t l an i r l t c r r r r r l i v c r r r c t l r o t l i s l o l r c l r t _sc t l o f i x c r lr l i r r r c . s i . . s , a l l o r v i r r g vc ry l i t t l c o r l r ' s l r . i r k r r l i c . [ J . r r c r - t l r cscc .o . t l i t i o r r s l css chu rgc t ^kcs p l . cc i r r t r r c p r r ys i i r r l l . , r opc r t i cs . It hc f i b r c , t hc v . l t r cs f o r c r c ' i c r , t c ruc i t 1 , , , , r u i l , , [ , , , , r r . r i c . r i c r r s i b i r i t yr c r r ra in i r rg a l rnos t r rnu l t c r c r l .

l l tttt-,\ 'ctt irrTi

o r r c o I t l r c n r o s t i r r r p o r t a r r t l r n t l r r s c f t r l l ) r o l ) c r r i c s . I I , t : I ' r r . l y c s r c r

365

F - F - F F F - - -

I I A N D I I O O K O F ' l ' I : X l l L I l I T I D R I I S

f i b r e s i s t l r c i r a b i l i t y t o t t r k c o r l a ' p c r l r l i t t t c t l t s c t ' r v h c n s l t a p c d

r t l r i g l r t c r r p c r a t t t r c s . I ; o r c x a t r l p l c , p l c a t s l n a y b c i n s c r t c t l i n

a I , l i r l ' p o l v e s t c r I i r L r r i c i n s U c l r a w a y t h i l t t l r c y i l r c l r i g h l y

t l L t r a b l c t o r v c l r i r r g a n c l l a u u c l c r i n g . P r o v i d c d i t i s p r c s c l t t i t t

su l l i c i cn t p ropor t . ion , P l r - f po lycs tc r f ib rc a lso confc rs th is

p r o p c r t l , o n b l c n d e t l f a b r i c s c o n t a i r r i n g i t .' l ' h c

n b i l i t y o i P l r ' l ' p o l y c s t c r f i b r c t o a c c c l l t a ' p c r t t t a n c t t t s c t '

i s n o t i r r f l u c r r c c d b y t h c t c u r p c r : r t r t r c o I a n y p r i o r I i c a t - s c t t i r t g

l r c a t n t c n t c a r r i c d o U t t o c o n f c r r l i n t c n s i o n a l s t a b i l i t y . l n f a c t ,

i t i s c s s c n t i a l t h n t l r n y f a b r i c t o b c p l c a t c d o r c t t r b o s s c c l b c p r c -

v i o L r s l y I r c a t - s c t a t a s u b s t l r n t i a l l y l r i g l i c r t c l t r p c r a t i t r c t h a r t

t l r a t r c r t r r i r c r l i n t l r c s h a p i n g t r c a t l l ] e n t i r t o r c l c r t o c l i r l l i n a t c t l i c

p o s s i t r i l i t y o f r r n c o u t r o l l c r l s l r r i n k a g e t l L t r i n g t l r c p l c i r t i n g p r o c c s s .

I ) l c : r t s s c t i n a g a r r n c n t i n t h i s r v a y r v i l l b c p c r t t t a r t c n t s o l o n g

a s t l r c s c t t i n g t c l t l l ) c r a t r t r c i s n o t s u b s c r l U c n t l y c x c c c d c c l . ' l ' h c

I c n t l ) c r a t r l r c u s c r l i n s c t t i n g i s s c l c c t c t [ r v i t h t l r i s i n v i c r v , c s p c c i i r l l y

r v l t c n t l r c g l r r r r r c n t r r r u s t r v i t l r s t a n r l i r o r r i n g . A r r a 1 1 1 l I r c l f a b r i c ,

f o r c x u r i l p l c , r v i l l c o r n n r o n l y b c l r c a t - s e t a t t c n l p c r a t t r t ' c s i r l t l t c

rcg ion o [ 200-220 'C.l n l p r o p c r l y h c a t - s c t i a b r i c , t h c f i b r c s r v i l l t c r l c l a l w a y s t o

r c v c r t t o t l r c i r s c t 1 ; o s i t i o r r . I I e l t - s c t t i r r g c o n t r i b u t c s g r c a t l y ,

t l r e r r c f o r c , t o t l t c t l i n r c n s i o r r a l s t a b i l i t y a r t t l r v r i r t k l c r c s i s t a r l c c o I

I ) l r I ' 1 r o l 1 ' c s t c l f ; t l ' t i c s .[ ) t r r i n g h c n t - s c t t i n g , f t r r t h e r c r y s t a l l i z - a t i o n o I t l r c p o l y c s t c r

t a k c s y r l r r c c , r e s u l t i n g i n a n i n c r c a s c i n t l t c s t i [ I n c s s o f t h c f i b r e .- l ' l r i s

rnay a{ l -cc t t l te hand lc o I thc tabr ic , rv l r i ch bccot r rcs c r ispcr .- l ' l r i s

c f l cc t i s a l lev ia tcc l by subscqr rcn t tncc l tan ica l t rca tnren t o f

t l rc fabr ic , a t r t l t l t c scq t lencc o [ { in ish ing opera t ions is o f tcn

sc lcc tcd tv i th t l t i s i r t r - I l i nd . I f hca t -se t t i r rg i s car r i cd ou t be fore

scor r r ing ar t t l / o r dyc i r rg , [o r exantp le , thc inc reascc l s t i f lness o I

t l t c fabr ic rv i l l bc la rgc ly workcc l ou t c lu r ing thc la t tc r opcra t io t rs .

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a c c u r a t c l y c o n t r o l l e d c o n d i t i o n s , a s a 5 " C . v a r i a t i o n i n t c r l r p c r a -

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o n s r r b s c r l t r c r r t d y c i r r g .I f h c a t - s e t t i n g , [ o r o l t c r c a s o l l o r a t t o t h c r , i s c a r r i c i l o L t t a f t c r

c l l , c i r rg , i t i s ncccss l r ry to sc lcc t thc r l ycs t t r f l s w i th l l l r r t i c t r la r c l t rc

i n o r r l c r t o l i l i r r i u r i z c t l r c c l l c c t o I r l y c s t t r l l v o l a t i l i z - a t i o r t . l t r t l a y

b c n c c c s s a r y r r r r r l c r t h c s c c i r c u r r r s l l t t t c c s t O s o f t c r t t h c h c l t - S c t

f l b r i c b 1 ' c r r l c r t d c r i l t g t l r o t l t c r l t t c c l t l t l t i c a l t r c a t r t t c t t t .' l ' l r c

r l c v c l o p r n c r r t o [ ' p c r n t a n c n t p r c s s ' t c c h t i i q t t c s t l t t r i t t g r c c c r t t

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v c a r s h ; r s s t i r n u l u t c t l u r r i n c r c : r s c r l r i c n r : r n r l f o r I , l r ' l ' p o l y c s t c rI l b r c s . I t c r n - r a n c . t p r c s s i s i r l o g i c a l s t c p f o r , , v r r r r l i ' t l r c c r c a t i o r ro I c a s c - o f - c r r r c g i r r n r c r ) t s , i n w l r i c h t l r c l r c : r t - s c i l i r r g o { r l r c l l b r ct l r k c s p l : r c c u f t c r t l r c g a n n c l ) [ l r l r s [ r c c n r r l r t l c r r p .

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i t s c l f i s s c t i r r t h c c l c s i r c r l s l l n l ) c .I ' � o l y c s t c r f i b r c s g c r r c r a l l y h a v c p r o v c r l l n o s t s r r c c c s s f t r l i ' t l r i s

r c s l ) c c t , c o n r r n o n l y i r r b l c n d s w i t l r c o l t o n , a r r t l t l r c n r p i r l r r r l v l r r c co f P c r r r u r n c n t p r c s s l r ; r s b c c r r a r r . . j o r f a c t o r i n t l r c p o l y c s t c r f i c l t l .

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A l l l i b r e s a r c a l l ' c c t c d b y t l r c l a r l i r r r i o r r s i . s u r r r i g l r t , r v l r i c l r b r i n ga b o u t c l c t c r i o n r t i o r r o n p r o l o r r g c t l c x g r o s r r r c . l , l . r l ' p u l y c s t c r i sb e t l c r t l r a n r r y l o n i n i l s r c s i s t a r r c c t o s u r r l i g l r t , r r r r t l t l r i s s t r p c r i o r i l yr s n r o s t p r o n o u r r c c d r v l r c n I l r c t i b r c i s b c l r i r r t l g l l s s . I ) l : 1 1 . , o l y c s t c rf i b r c s l r n v c c s t ^ b l i s l r c r l a r r s c I L r l r n r r r k c I i r r t l r c c r r r . r r r i r r l i c l r l , l u r g c l yt l r ' o t r g l r t l r i s i r r c r c . s c r l r c s i s t : r r r c c t o t l r c c l l c c t s o I s t r r r l i g l r r .

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I ) l : ' [ ' p o l l ' e s t c r [ i b r . c s l r : r v c a ' r c x c c l l c r r t : r l l - r o r r n t l r c s i s r . r r c c r oc l r c r n i c r r l s . ' l - h c y l r . v c i r s r r r p l i s i r r r l y g r o c l r c s i s t : r . c c t , : r c i t l s ,b r r t ; r r c I c s s r c s i s t a n t t o a l k : r l i , a n c l t i r i s r r r t r s I b c b o r r r c i r r r r r i n di n t l r c s c l c c t i o r r o f ' [ i b r c s l o r i n t l r r s t r i a l : r p p l i c : r t i o r r s .

l ' l i . l ' p o l y e s t c r I i b r c s a r c l r o t a f l c c t c d a J r p r c c i r r b l y b y . r r y , I t r r cn o r r r t r l b l c a c l r i n g I c c l r r r r c l r - r c s .

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c x c c l l c r r t c l c c t r i c a l p r o p c r l i c s o f l r L . . l ' p . l y c s t c r [ i b r c s a r ca l l i c d r v i t l r g o o c l r c s i s t a n c c t o t l r c c f l c c t c l I l r i g l r t c n r p c n r t r t r c s , c . g .1 o 1 8 0 ' c i . A s t l r c r r r o t l c . n t r c r r d i s r o r . ' c l c c r ' i c . l r r r o t o r s r i tl r i g l r c r I c n ) l ] c r ; r t u r c s , t h c r c i s a c l c r r r : r r r r l [ o r g o o r l i r r s u l l t o r s r v l r i c l rr v i l l w i t l r s t a r r c l c l c v a t c r l I c r ] r l ) c r u t u l c s . I , l r . l ' p o l y c s t c r f r r b r i c s , l r c l t -. s c t a t t e l n l l c r a t r r r c s a b o v c t l r o s c c r ) c o u n t c l c d i r r p r l c t i c a l u s c ,I r l v c [ o r r n c l r n n r r l , l p p l i c a t i o r r s i r r t l r i s f i c l t l .

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l r c P l r c r r r r r r c ' o n o f - p i l l i r r g i s a f a r r r i l i u r . r r c i n t l r c u , c r r i r r r io i f l r b r i c s f r o r r r l l l t y p c s o I s t l p l c f i b r c . S r r r , l l [ r L r r r t l l c s o I l i b r . c sc o l l c c t o r r t l r c s t r r l r r c c o f l l r c I l b r i c t l r r r i r r g u s c , l o r . r r r i r r g ' p i l l s 'r v l r i c h a r c I r c l d o r r t o t l r c [ r r L r l i c s r r r l ' i r c c b y f i b r c s g r i p p c r l l t o n c

I I I \ N I ) I I O O K O I I ' I

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c n ( l b y l l r e ! ' a n t r u r d a t t h c o t l t c r c n c l b y c n t l t t t g l c t t t c n t i n t h cp r l I b u n c l l c .

I n t hc case o [ f i b res s t t c l t as u ' oo l , t l t c sc p i l l s I t r ay be r cn tovcc lf a i r l l , c a s i l y , e . g . b y b r u s h i n g . R u t i n t l t c c a s e o I a s t r o t r g f i b r c

s r r ch as P l r ' f po l ycs t c r , t hc f i b r cs ho l c l i ng t he p i l l s c l o no t b r cak

c a s i l y , a n d t h c p i l l s r c n r a i r t a t t a c l t c c l t o t h c g r t r t t t c n t s t t r f a c c .

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\ vc l vcs , anc l t he t cnc l c t t cy t o p i l l can bc r c t t t ovcd c f l ' c c t i v c l y f r o r r r

I ' �E ' l ' po l y ' es t c r c l o th by ca rc [L r l s i r r gc ing o f t hc l oosc f i b re cnds .- l - l r i s

i s ca r r i c c l ou t p r c [ c rab l y a l t c r c l yc i ng , as f uscc l po l yes te r

f i b r c s t c n c l t o d y c t o a d a r k c r c o l o u r .I r ' l any n ranu [ac tu rc r s a re now p roduc i r r g po l yes t c r f i b r cs o f

lorver tcn i ic i ty , rvh ic l ' r l tave a rcdr - rced p i l l ing tendency.

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P l i - t ' y ro l ycs t c r f i l l n re r t t ya rns t nay be . sub j cc t cc l t o Lhc p rocesses

t r scc l i n 1 ; roc l t r c i r r g t cx t t t r c t l y l l t ' n s . So t t t c o I t l r c sc y r rn r s sho tvac l v : r n tagcs ovc r t ex tu r cd ny lo r r yan rs , f o r cxa t t r p l c i n l r r a i n ta i n -i ng s t r l l c r i o r r vash / r vca r cha rac t c r i s t i c s , r v r i nk l c r es i s tancc andrccove r ' ) / [ r o rn . s t r c t c l r .

P ro r l t r cc r - t cx tu r cc l ya rns havc had a no tab le success , such asthe f a l sc - t r v i s t bu l kcc l ya rns r vh i ch a re cha rac te r i zec l by l o r vs t r e t c h a r r c l h i g h l e r r g t h s t a b i l i t y . ' l ' h e s c y a n r s a r e u s c c l , f o r e x a n r p l e ,i n t l r e r r r e n t r f a c t t r r e o I c l o L r b l c j c r s c y a n r l o t l r c r k n i t t e d f a b r i c s ;t h c s c a r e r l l o r e s t r e t c h r c s i s t a n t a n c l [ c s s l ) r o n e t o s l r r i n k a g e c l u r i n gp r o c c s s i r t g t l t a n c o r r t p a r a b l e f a b r i c s n r a c l e f r o n r b u l l < e d n y l o n .

I l lcnds

A l r i g l r p r o p o r t i o n o [ - t l r c o u t p u t o f I ' 1 1 ' l ' p o l y c s t c r f - i t r r c i s i n t l r cf o r n r o l ' s t a p l c , r v l r i c h i s r v i c l e l y u s e c l i n b l c n d s r v i t h r v o o l , c o t t o r r ,v i scosc and f l r x .

I l l c r r c l cc l r v i t h co t t o r r , I )E - f po l ycs t c r f i b r c i nc reuscs t hc r vc r r r; r n r l i r b n r s i o r r r c s i s t l n c c , c s l ) c c i a l l y r r s t h c 1 ' r t ' o p o t ' t i o n o f p o l y c s t c r

f i b r c r cachcs 50 pc r ccn t a t t c l n to r c . C rc : t sc l ' c covc r \ / i t t t p roves ,

a r r r l : r f a b r i c c u n t a i n i n g 6 7 l t c r c c n t I ' E ' l ' p o l y , c s t c r / 3 3 l l c r c c r t t

cc> t t o r r l u r s p rovc t l p : r r t i c t r l r r r l y s r r cccss [ ' r r l I o r s l t i r t s , t ' r t i t t r vc r t t ' ,j a ckc t s an r l su i t s . Thc f ab r i c l u r s t hc ha rc l wca r , cuse -o [ - c i t r c

; r r opc r t i c s assoc ia t c r l r v i t h t l r c l ' 11 - l ' pc l l l ' c s t c r f i b r c , l t t t c l t l r c

I u r r r r l l c , o p a c i t l , a r r r l a b s o r b c t t c y o I c o t t o r r .

n : - s Y N ' t i l [ . t t c F t t ] t U : S

I l l c n d c c l r v i t h r v o o l . , P E ' l ' I r o l y c s t c r a t l c l s c r i s l l n c s s o I h ' . c l l c ,\ r ' c r r r r c s i s t a n c c , t o u g l r n c s s a n c l s t r c n g t h .

' l ' l r c c l l c c t o f t l r c I r E I -p o l y c s t c r i s t t l o s t l t o t i c c a b l c i r r f a b r [ s s u b j c c t c r l t o c l . r ) l ) c o r -c l i t i o r l s , j n r v l r i ch t l i c r voo l bcco r r r c . s l i n rp an i c l s i l y . , . . , , r " . l . : i i l ' ' .

p r c s c n c e o I I ) E - l ' p o l l ' c s t c r l l r o v i c l c s . , ' . i r . r ' c . s i s t a r r c c . r r r l r l i r r r c r r -; i 9 n a l s t a b i l i t y , f o r c x a r r r P l c i r t l r . s c r . c g i o r r s o I t l r c b o d y * r , . , .l r i g h h t r n l i d i t y i s l i a b l c t o r u r r r p l c r r r r r l c - r c : r s c a . . l l - r v o o l f . b r . i c .

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I \ 4o . t f ab r i cs con t , ' i r t i r t g l ) l l ' l ' I r o l l , c s t c r f i b r c l r . c r vas l r r b l c , b t r ti n b l c n d f a b r i c s t l l c t t i t t u t ' c o I r i r c - o t h c r c o n r l ) o n c r r t r v i l l g c r r c r : r l l ycon t ro l t l r e bc l t i r v i o l r r o I t l r c f ab r i c r r r r r l . l r t l i l l ' c r . c r r ,

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c o r t d i t i o n s . 1 - h t l s , r v o o l , s i l k , r c g c r r c r : r t c d c c l l u l o s c s ; r r r r l c c l l t r l c l s cacc ta t c f i b r cs a re r c r : r t i v c r y r l c l i ca t c I i b r . cs r v l r i c l r co r r l r l t ; ;da r l t agcd j f t oo^ - scvc rc r v : r sh ing co r r r l i t i o l s r vc r c t r sc r J . t ] l c r r t l s o fI ' 13 ' f l l o l yes t c r f i b r cs r v i t h co t t o r r o r f l ax , c l n l hc o t l r c r . l ; r 1 r l , 1 r . cg c t t c t ' i l l l y l t t o r c r o t l t r s t . ' l ' l t c c o n t l i t i o r r s r r s c r l i r r l n r r r r t l c r . i r r g b l c . r r t l so I I ' �E ' l ' Po l ycs t c r I i b r c w i t l t o t l r c r f i b r cs l r r c t l r c r . c l ' o r . c con t ro l l c r lr ) r o re by t he o t l r c r f i b r cs t r r a ' by t r r c I )E ' r ' po r l , c s t c r ., P l r ' f po l yes t c r I l b r c l t l t s t l r c va l r r : r b l c c l u r r i r c t c r i s t i c o I con -[ c r r i r l g ' l t l i t t i t t t t l l l l c a r c ' p r o l ) c r t i c s o n f a b r i c s c o r r t ; r i p i r r g i r . ' l ' l r cdcg rce o [ ' r l t i t l i t r l t t t t r

ca rc ' ach i cvcc l c l c l l cnc l s l r r r gc l y o1 t l r c 1 r r : . -po r t i o t t o f P I I - f po l l ' c s t c r f l b r c p r csc r r t , bu I r r r os t r r r . t i c l cs con -ta i n i ng I 'E - l ' po l ycs t c r f i b r c , i I l v l r s l r cc l co r - r cc t l y , r . c c ;u i r c 1 t l r es to n l y l i g l r t i r o r r i n g .

PE ' - l ' po l yes t c r f i b r cs l r avc h igh s t reng th l n r l l t l r : r s i s ' r cs i s t l r r r cc ,a t t d t h c y w i l l w i t l l s t : r r t c l v i g o t ' o t r s r r r c c l i a n i c r r l r v l s l r i p g l r . c u t r r r c r r t s .I t i s ' o t , c ccssa ry t o t . cu t 100 pc r cc ' t I r [ , ' l ' l l o l ycs t c r . g .o r l sas i I t l r c y wc rc l l l l l c l c l r on t l c l c l i ca t c l r ag i l c n rn t c r . i r r l , c vcp r l i o r rg l rI i g l r t l y co ' s t r t r c t c r t f ab r i cs r r : r y g i vc r r r I s , , y r1 r . . , , . , , , . , . . .

I ' � E ' l ' 1 ; o l y c s t c r f i b t ' c s l t a v c a l r i g l r r c s i s t , , , . r i . . t u c l r c r r r i c r r I a t t : r c k ,a n c l l t o l l c o f t h c t l c t c r g c r t t s o r c h c r n i c ; t l s c o r r r r r r o r r l y t r s c r l i r rr v l t sh i t l g , i r r c l r r c l i ng l l c rox i c l cs , pc r - s l l t s , l r l , l l o c l r l o r i t c s , : r c i r t s l r r c ta l k a l i s , r v i l l b r i t t g a b o t t t i t t t y s i g r r i f i c l n t c l c t c r i o n r t i o n o f t l r c I , l i ' l 'l l o l y c s t c r f i b r c t t t t t l c r c o r t t l i t i o n s l i k c l y l o l r c c p c o r l r l c r . c t l i r rt l t c l a t r r r c l c r i n g o f t c . r t i l c s . V i g o r o t r s t c c l r n i c l r r c s r r r r r y l l r t r s b c I r s c c l ,c n r r b l i r r g s o i l t o l > c r c r r r o v c r l c f l - c c t i v c l y .

. I r : r b t ' i c s t t r a y b c l r : l v c - l ) c r i c c t l y s : r t i s f i r c t o r i l y r l t r r i n g l l r r r r r l c r i r r l S ,

b t r t t l r c y r c r f o r " r r cc o I l r r ^ r r c - r r f g r l r f r c . r t s r v i i l r r c r r c r r t r c l r r co r r . cc tt I i r t t r l t i t r g s a t t c l o l l l h c t l s c o f i t r i t a b l c r r r l k i r ) g - u p t c c l r r r i r l r r c s .' l ' l t t t s ,

l l ' l l l l ' l y g i l r l l r cn t s r r r r c l c f r on r I r cav i c r -w ,c i g l r i l , l : l ' pg l yc i t c r l

t- t- r- Lt L |.

I6 f i ( ) n 369

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*ooL r rn i f o l t t t f l Lh r i cs , sL t i t i ngs i t t t d t r ' c l L t sc r i t r gs l l r c s t l i t l Lb l c o l l l )

f o r r l r r ' - c l c rn i ng , r s l l r c ! havc i ) o t L r ccn dcs i t l l l cd t o bc r vashab l c '

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n rLv l , ' c * l shcd s i l t i s t ac to r i l y i r t a r r r ac l t i r r c o f by l l a l l ( 1 , bu t t l r c

r r sc o I cxccss i vc r vas l t i ng t cn lpc r l i l l . r r es I t t ay I csL t l t i t t < l i s t L t rL tancc

o f t l i c p l e i l l s ; hanc l o r t r l i l t l I t t l t c l l i t l c *as l t i t l g i s gcnc t i r l l y t o bc

rccon r r r t c t t d cd f o f f l c l l t cd g l t r n l cn t s

A l l l r r opc r l l ' cons t i t r c t cd l t l d l j n i s l r cd I ' l r i I ' po l l ' c s t c r f ab r i cs

w i l l posscss s . r t i s f ac lo r y c l i t l l cns io t t l t l sL lb i l i t y t o t hc \ \ ' es l i i r l g ,

c l r 1 , - c i can ing and i r on ing con r l i t i o t l s t hc , v a l c cx l ) cc l c ( l 1o

cnco r r D t c r i r l t l s c .

l l / us l t i ) i g / l !si . \ l ul t I s

No rn rn l I i c l r r i c l dc te rgcn l s a r c good g rcasc l r n t l o i l cn lu l s i f i e r s ,

bL r t I ) a r c l ) oo r so i l - sL t spcnd ing p fo l ) c r t i t s . ' l - l t c l

a l e i l l i i ( l eqL ra l c

fo r r . , r r s l t i ng hcev i l y so i l cd r r t i c l cs , as t l t c so i l n l l t y [ r c r c - ( ] cpos i t cd

on t hc f i l ) r c . Sv l l r cL i c f i b l cs i n l l r l i c t l l l r r ^ l c p ronc t o t hc

c l cpos i r i on o l so i l f l o t t t suc l l l vas l l l i c l L to r s , a l l d i r bc t l c r r cs t l l t i s

o b i l i n c c l L r s i n g e i t h c r s o l p o r a ' b L r i l t ' ( l c t c r g c l l t , l t o t h o f l v l i i c h

I t avc sL rpc r i o r sL l spcnd l ng po l ve rs .

Soap i s s r r i t ab le f o r so i t $ ' l t c r a l c l s , b t t t i t c l t t t r l o t bc t l s cc l a l o l t c

i n ha fd w r t c r . l r l h i l r d wx t c r d i s t l i c l s , l l l c ac l c l i t i o r t o f 1 r scq t l cs t c r -

i ng i l gcn t \ \ ' i l l p r cven t l l l c depos i t i o t r o I a l i t t t c scL l t l l ' l

l l c r t sc

u i ' t r u i l L ' , l " t " . g "n t -bese t l r vas l r i ng po rvdc l s o f t l r e t ypc t l s cd f o r

\ \ ' l i i t c co l l on a r t i c l es i s l l so r cco l t l n l cndcc l

l l : a s I t i t r g ' l - c t t t l c r a t u r c

' I hc $ r sh ing I c I l ] f c l i r l L l l c s l t oL r l r l bc kc l l t ; r s l ow as poss ib l c . an t l

i n gcnc ta l sho t t l d no t cxcecc l 40 50 'C . j n < lon l cs l i c wash inS ,

a l rho r rgh h ig l r c r t c r r l pc l l t L l r cs c l t t bc r . t s cd i n con ln te r c i a l I l Lund ry

P ro cc ssc s .I ' l J l po l l c s l c r i s I l l i c rn top las t i c l i b r c , r nc l i t i s I i ab l c t o

c r " l s " a i t c t t r pc r r i t t t r cs t t bovc 50 60 'C . I f coo l cd i n t l r i s co l l d i t i o l l ,

l l r c c r c l scs pc rs i s t i l n ( l c l i n bc I c r t l ovc t l on l y by i t c l t r i r t g C rc l t s l l t g

l c n ( l c r ) c i c s c l t r h c I t c l l l v t c d t l c c r l h y p t o r l r c s s i v c c o o l i r r l l ( ) l t l ] c

r i nsc l i q t r o r f r o t t t r v rLs l l i r l g t c l l l l c ra t t l t c t l o r v r l l o co ld - r va t c r

l c n r p c r : l l t r c \ ! l r i l c c o l r ( i n L l i l l g t o a ! i t l l l c t l l c g l l l n l c n l s '

I ' r r � r 1 l , " ss i vc coo l i ng o I l l l i s t l a (L t r c i s r ] o t i l r f r l c ( i c l t b l o i r l

( l o ' r r cs l i c \ \ ' i ! \ l r i r r g as i r t co tn r t l c l c i ; r l l l L t r l l t l c r i l l g o r f l h t i c l i t t i s l t i t t l i ,

I ' u t i t i s l . oss ib l e t o f o l l o r v a ho l r vas l t r v i t l t I r va rn l r t nsc i l t l ( l

l c l r i c vc a t c r r so t t l b l c co t t t p ro t l l i s c .

-170 3 7 1

I l I S ) . N I l t t r t a i f l ! I l t : s

l :o11 lvl trkiug' I

I r c r l c f c t s i L i o n o I d L t s t a n d s r l o k c p l r r l i c l c s n l r v c t r L r s c , f o g

r r r l r k i n g ' o f t c x l i l c s , c s l ) c c i l l l l ) ' i n d r . t , r r L n r o s p l r c r c s l L r r t l o u I - r L b r i c s\ \ h i c l t a c c l r n t L t l i l l c l l n c l c c l r o s t i l t i c c l t i l r g c l : o ! n l l i r k s i u 0 n o l i c c ,a b l c a s c l u r k b a r s i n f o l d c d c l o l h , o r a s a ' g r c 1 , i n g ' r o r r n r l t l r c l o r v c rc d g c s o I s l i p s o r s i n t i l a r g a n l c r ) l s .

' l l r c c l l c c t i s o I s c c o n d u r y

l n r l ) o f l a ' l c c i n s l t i . t s a n d o t l t c r a r t j c l c s * . l t i c l r s o r l I r i r l ] r t r i l y b yp l r t ' s i c l I con t l c t .

V i g o r o r r s l a L r r t r l c r i n g r v i l l g c r r c r a l l y r c n t o v c f o g r l r r k i r r g , l r r r tl h e a ( l d i t i o n o f a D o n i o n i c d c t c r g c r ) t o r c i r l i o n i c s o f l c c l l o t l l cl i r r a L r i n s i n g r v a l c r w i l l p r c v c r ) t r e c u r r c n c c .

Loca l i z t t l So i l i ng o l G un t l c t r t s

S o i l i n g a t t l t c c o l l l r s a n d c u l l s o f s l r i r t s , b l o L r s c s i i r r r l s i n r i l ; t rl i t t e ( l gan11cn l s i s due p r i n l i i I i l y t o con t l l c t w i l l r t l t c sk i r t f t r l l t c rt h i l n l o s t i r { i c c h r r g e s . S L r c h s o i l i s c o n r p o s c t l l ) l t t l y o I g l c i r s yr ) x r t ( c r , l ) l l f t l y o I t l t c s k i n p i g n t c r r t n r c l u r r i r r , l r n r l l l r r l l y r _ r f p l u . t i c l c . so f so l i d nn Ie r , , vh i c l r hevc r vo rkc r j j n t o t l t c y r r r ns . '

I f l l t c s t l i ns a f c I t c . r v j ' , t l t c y a r c bcs t r . c r l ] ovc r l by s l ) o t t i l t { l \ \ , i t l rne i i t se iL l ) o r dc l c fgcn t aDc l f l c x i r r g l hc [ r r b t i c by l l r nc l . l l r ct r t cc l r an i ca l t r c t i on l t e l ps t o wo fk l l l c so l i c l l l r r t i c l cs oL t t e I l l r c) ' i l f n s l r t t h c s l n t c l i n t c l l t c g r c l s y r ) ) l r l l c r i s c r r r L r l s j l i c c l . b o t l rt ) l c s o f so i l bc i ng r cn tovc ( l by sL lbscqucn t r v l i s l r i ng . l r r r l i l l i c r r l tc i l s cs , a i nc tas i l i c i t t c t r ca t t cn t i s t l c s i r ab l c .

( l rcrt.r t , att l Oi l ,Stoit ts

I r g ra incc l g f cxsc s t i r i ns l r r c d i l l i cu l t l o r c r ) t ovc f r o r t r l , l i - 1 . po l l . c s t c rf a b r i c s , a r r d l r c p l r r l i c u l l r r l v o b v i o L r s o r r l l l l i n , s c l f - c o l o r r r c t lr r r l c r i r l s . l l t c b c s l n l c l h o ( l o I r c r n o v a l i s l o s l ) o l t l t c s ( l i n r v i t l rnca t l i c l r r i c l ( l c t c rgc l l l , r vo l k l l r i s i n to t l t c f t r b r i c , an r l I c r r vc f o r2 J h o L r r s p r i o r t o l l L t n d c r i n g . A l t c r n l L t i v c l y , c l r v c l c l r r i n g n r r r y[ r c nccess l r y .

l : o r g , r n l c h t s l h i r t i u c c r ( c n s i v c l y s o i l c d r v i t l r o i i , c . 1 g . c n l l i n c c r s .( ) v c r i r l l s , d c { c l g c n l s t a t h c f l l r l n s o l t l t s e t c t c c o n t t c n t l c r l [ o t) u t t n d c r i n g . b ^ o i t p s l t o u l ( l n o t b c u s c d i n t l t c c l r l l y s t l r g c s o fl l un r l c r i ng a r l i c l cs r r l t i c l r l r r c l r cav i l l . con l i u ) t i r r a l c ( l * . i t l t o i l ys o i l , b c c ; r u s c o f t l r c r l l i n g c r o f l l t c s o l r p / o i l c r r r L r l s i o n c r l c k i r r l S .

O v c r r l l s r v h i c h a r c c o n s i s t c n t l y u s c d t r n t i c r c o r r r l i l i o r r s r v h c r cl l ) c y b c c o n l c h c l v i l l ' s o i l c d r v i l h o i l - b o L r l d < l i r l * i l l b c n c l i t f r o r ld r 1 ' c l c a n i n g a t i n l c r v a l s o f l 5 2 0 r v ; r s l r c s . I l r c r ) r o s t s L r i l l b l c

I I A N D I } O O K O F T E X T I L E F I N R E S

freqtrency rvil l be deternriucd by expcricnce in each particularcase.

Drl i g

PET polyestcr fabrics absorb very l itt le watcr, and most of thewater in a wct article is ir the interstices of the cloth. Garmentsdry quickly and easily whcn hung in the air.

Thc spin<lrying of hot wet articlcs, followed by rinsing in coldwater, is particularly to be avoidcd, as is prolonged spinning,wlrich has a strong cooling eflect. Bad practice of this nature ismost. l ikcly to occur whcn using 'twin-tub' washing machincs.

Tumblcr drying in hot air helps to rcmove washing crcases.After the garme ts arc dry, tumbling should be continucd for5-10 minutcs without heat to allow progressive cooling.

Ironing

PEI polyestcr articles rvhich havc becn washcd corrcctly wil lnecd litt le or no ironing. If necessary, however, ironing nray becarried out cllectively by steam ironing or dry ironing at'synthctic'setting on thc rcverso side, or with the help of a presscloth. Ironing tclrpcraturcs should not cxceed about 135"C.Sticking occurs at about 250'C-

Dry Clcnnirrg

PET Do lycs tc r f ib rcs a rc h ig l l l y res is tan t lo n l l the c l rcnr ica lslikcly to be cncountcrcd irr dry clcaning, and no spccial precau-tlons arc nccessary.

Errd Uscs

The inrportant propcrties of PET polyestcr l ibrcs, f i lanrent andstaple, may be sumrnarized as follows:

1. Low moisturc regrin.2. FIigh dry and wct strcngths.3 . [ I igh in i t ia l n rodu lus .4. Fligh rcsistance to and recovcry from bcnding.5. Lorv crecp.6. Abil ity to be hcat-set.7. Fligh abrasion rcsistance.8. Good clcctrical insulation propertics.9. Good rcsistancc to cxposurc to elcvatcd tcnrpcraturcs.

J t !

r l r - l r I r l r I r [ r I r J r - t

B : S Y N ' r I I E ' I I C F I I ] I I E S

I0. Cood rcsistance to most contnotr chcnricals,ox id iz ing

. lnd rcduc ing tgcn ts . Goo( l 1 ' " r i r f , , , , " ' "uood rcsrs t i rncc lo d i l t r te a lka l i s , bu l a ackcdcent ra ted , ho t a lka l i s ,

l l , Cood rcs is la t rcc to con ln ton so lvcn ls .

inc lud ingto l | c ids .by co[-

","#i"lll":'::"i',,1:J,.::.,.i,".?:l:T,,i'lll'.ii;l;;,lf1:l:i:"i1"[ll,tlll ib rcs to bccornc onc o f thc r )os t vc rsn t i l c u f , , f f i ,o , f . rn l v , , i f , " t i "f ibres.

Apparel FabricsPEf p -o lyes tc r f ib rcs l r l vc rn ldc l l t c i r w y i r ) to v i r l r | i r l l v cvcrvtypc oI apprrel cnd usc. Alonc or irr blcrrtls ,"i,fr� *",, i,r"", i",,1

i;[; :'l ;l?::*o":n;,'i"i, ["]J:'l "',i r,' cs pro uii," ;,; ;";;'';;;

wr r h h ish rri,ncnsionar,," 0,,,,, ;illi'#ljll;'?:l;l;ili:' si' rn,c,,rsI nc sn.cngl r i rn( t ( l in lcns ioni r l s l l l ) i l i ty o f I , l i . l , po ly( ,s tcr l i l l -r ) rcnt y i r rns cr rablc t l rc r rurr rufacturcr to p i .oc lucc .1, . ; r , l iA iur ; . ; ; ; , ;

:"J,1' 'j:i, Jii'";,J:"n,:1[:"",;.J::ll; :llnll;;:l*,i:lifl I lfliishape and appcarancc. Contirruohavc .foun<r' t",p",.lniit-o,,rl"r,"lii iiilil:ll, ftil, iljf x;i,il,fi;l ingcr ic .Full-handling fi lamcn t fabricsa rc nr a crc r,o,,i p,.oa u.".-i " * i iilt'.'li

" ; Jir":lfj: i:l ;::l' *lli'::

iil,'J"3i,'|,',ft i'i,,l,li,.ilT"r",,ll",ll,tT*;,ili',"?l;t".;l;ll:x li;J,#iifui, iili.i:,: "Tffi'J:i,,,v ;i; b i;; ;;,,';;;;; il;';

.PEf polycstcr staplc fibrc provi<lcs yarns arrd frrtrrics witlr rhcLl,lr:_i:J!:q'i[,'Tilflii,i"",:i,:,J,lilt"i:tiil,,yt jli;of cn t rapped a i r .

Suiting fabrics ntadc fronr pE'f

i:tfiyjlr;: ;:1 1i"J,#i1i"ltii L$,il;ilt";t:,:?'i;i lti];i n -a crc_q uate ;;;";i;; ;' ; ;u,i:'"i,l,il,llii", :lffi li[l:"l;licvcrr aflcr prolongcd conlintrorrs rvcar.CurtainsThc good resistirncc to srrnlight which is n fcuturc of pl].l. poly_

J73

r

l-I F F I I I F F F F F F t F F F F |l'|l f'�'�'i F I[ l ' I , l r I ' l I t I L I | , l t I t r I r l r ]l L ) l


ester f ibres, espccially behirrcl glass, has cnabled thgse llbres to

"ri^tl irf, I ' i iniportunt outlet in the curtain trade' The fast dyes

rt"o i" 'Jtlrf "-g'pET polyester fabrics have contributed greatly

to success in this l ield.

Floor Coverittgs

PET polyester f ibres have made good headway in the field oI

it*r iou'"tlngr, notably in the production of sliver knit rugs and

tufted carpcting.

LaunclrY EquiPnrent

The hcat resistance of PET polyester {ibres, all ied with strength'

fr^ri *."t ancl abrasion resistance have proved ot.great value in

laundry applications. Laundry-bags, dye bags' polrslred hcaq press

"o1"", t"tnOrv blankets, packing flannel and calender sheettng

;;;-;;;;;;;""tv maii r'orn-pet polvester fabrics' which

outlast the fabrics previously used'

Conveyor BeUs

PET polyester li lamcnt yarns are used as rcinforcement in rubter

""]i"Juti belts, ancl havo proved particularly valuablc in indus-

;;;;-;i";' i l1; are subjected io acid conditions' The PEt

o"iv"t*fi.i"ftt""mcnt stinds up well to acid which penetrates

into damaged belts.

Fire HoseThe high strength and high initial modulus of PET polyester

ni'i", ^ifi""

."4'" possible the production of fire hoses which are

. i r " "g ' " "a- i ight . 'Tnese hoses-are absolute ly rot - res is tant ' and

;";'"b"];i, o"utside without sullering signifi cant damrge'

Ropes, N ets, Soilclotlr

The strength, high modulus, resistance to light' heat' microbes'

;;;;;;l;:;; ';;;<l other influences have opened up.an impor-

i""i 'n.la of application in ropes, twines, nets' sailcloth' awnings

and other goods of this type wbich are uscd outooors'

Fill ingPET

-polycster staple is uscd as lil l ing in pillows' qLrilts' and the

37'l

B : S Y N T I I E T I C F I A N E S

like. Polycstcr f ibre fi l l ing js casy to wash and dry, non-allcrgcnic,springy and crush-resisting.

Sewing Thread

High strcngth and high nrodulus arc useful charactcristics in asewing thread, and PET polycster yarns havc comc into widc-spread use in Lhis application.

Ilosiery Dye ing

PET polyester dye-bags arc uscd in thc hosicry tratlc for dyeilg

nylon stockings. The PET polyester l ibre resists dyes uscd with

ny lon .

Papernuking

The felts used in paper manulacture must have a good rcsislatlccto moisture, heat and abrasion, and nlust bc ablc to stand forlong pcriods without rotting. PEI polycsicr l ibrc has provcd

especially satisfactory in this application, hnving thc nddcdadvantage of resisting the acitl conditions which rcsult wlrcnaluminium sulphatc is used as [i l ler.

Elect rical I rtsulatiott

The good dielectric propcrties and high strcngth of l 'DT polycstcr

fibrei are maintained at temperaturcs above 100'C., and fabricsnrade fronr these fibres are used in the insulation of elcctricmotors designed to operate at elevated tcmperatures'

Tyres

PET oolvester corcls have made substantial hcadway in tlr is

aoo l ic i t ion . Th is deve lopnten t has resu l (ed to so t t te dcgrce f ro t t t

thi increasing use of radlal ply tyrcs, i lr which tlrc rcil l [orcclrlcrlt

i s reau i red to l tave r t t op t i rnunt rcs is ta l l ce Io s t rc tc l l . l l l e l l l g l l

modilus of PET polyestir f ibres is an arlvantagc which enlblcs

thenr to compete e f fec t i ve ly aga ins t rayor l and ny lon i l l t l l l s

field.

315

I I A N D B O O K O F T E X T I L E F I D R E S

(2) POLY_I, 4-CYCLOI'IEXYLENE_DIMETI-IYLENETEI{EPIITHALA'I'E FIBITES (PCDT POLYESTER

FIBRES)

Fibres spun from poly-1,4-cyclohexylene-dimethylene tcrephtha-l a t e :

B : S y N ' r | E T t C r t 0 R l l s' I ' l rey

a re ava i lab lc in a rangc o I counts , c r in rp an t l s t rp lc l cng thsto mcet all requircrncnts,

PRODUCTION

PCDT polycster fibres arc spun lronr poly- t ,4-cyclohcx ylcnc-dimcthylcnc terephthalatc nrude by condcnsing tcrcphthrrlic rrcidwith I ,4-cyclohexancd inrc tha n ol :

--[ -ocl-tr-cH

ct I1-c.lt'

\"*.u,o.o-O-.o-],,cl t r -c l l ,

HOCU'-CH

Ll1! -L t t i

ru-cHlorr + lrooc-o-cooltI NTRODUCTION

In 1958, a new type of polyes{er llbre was introduccd to thctcxtile trade by Eastmarl Cher ical Products Inc., under the trademrrk Kodel.r

Kodcl fibre is spun from the polynrer made by conclensingtereplrlhalic acid rvith I ,4-cyclohexa ned inlctha nol (sce page 37'l)and il is thercforc o[ Iundamcntally dillerent constitution fromthe polycthylcne tercphthalate polycstcrs which fornt the bulkof commerical polycsler fibres. The polynrer fron which Kodel2l I is spun is poly-( 1,4-cyclohex ylene-dinre tlr ylcne terephthalate),rvhich may be shorlcncd convcrriently to PCDT polyester(

Sincc Kodcl rvas inlroduced, Eastnran Chcnrical Produbts Inc.have marketed anotller fornl of Kodcl, which is based on poly-ethylene terephthalate (PET polyester). The PCDT polyesterfibres are now designated Kodel 200-series, and the I'ET poly-estcr fibres arc Kodel 4O0-series fibres.

Thc infornration which follorvs is based upon datr availablefor Lodcl 2ll, which rnay be rcgarded as the original fibre otthe PCDT polyester type.

TYPES AND SIZES

Ilmctrnt SyDthcsis

(a) Terephthalic Acid

This is produced from p.xylcnc as dcscribcd on pagc 332.

(b) | ,4-Cyclohexoue Dine thanol'fwo

isomeric fornrs of this substancc are possiblc, lhc cis andlhe trotts. The nraterial used in producing PCDI' polynrcr is amixture of t l lc two isomcrs.

-

I 'olyurcriztt iort

Dimethyl terephthalatc, made by estcrif ication of tcrcnhthrlicac id , i s n r ixc r l rv i th 1 ,4 -cyc lohcx l i rc ( l in tc t l l i l no l , nnd thc l ! vorcactanls are healcd to 200"C. in lhc prcscncc o[ nn cstcr inlcr-changc catalyst. As condcnsation procccds, nrctlryl alcohol disti lsolT. Thc tcmpcraturc is raiscd gradually to about 300"C., vncuunrbe ing app l ied in the la tc r s tages , and hcat ing is cont in t rcd ur r t i lthc po lymcr has aua i r rcd lhc dcs i rcd r r ro lccu l l r r wc ig l r t . ' l ' l ) c po ly -rncr produccd in this way lrolr a nrixturc of cis and /rrrrlr

37'l

cHr-cr r,r / \-=+L-ocl{,-cll

./ccHr-clt,

il-cr,oco-O-.o-].

PCDT polycster fibrestow and top sui tab le

are produccd nrainly in the lornr of staple,for proccssing on all thc usual systcnrs.

'Rcg is tc rcd ( r rdc mark o fN.Y., U.S.A.

Easlmrn Kodlk Conrpany, l lochcstcr.

176

' l " l ' [ ' [ ' L ] : -

t F . t l n n n n n n n n F F E n F rI I N D B O O K O F T E X T I L E F I A R E S

isonrers of I,4-cyclohexanc dimethanol has a melting point of

about 290"C.

Slinning

Thc polyn'rer is melt spun in the usual way, thc fi lamcnts solidify-

ing is t irey nrcet the cold air. Tlrcy ate drawn to 4j to 5 times

thcir original length at a temperaturc of about 120'C.

PI{OCESSING

DesiziI lg

Knitted and woven fabrics wil l ofter.r coutain sizing naterials in

addition to clirt, oil and grease. Dcsizing and cleatring musl bc

carried out bcforc dYcing.Water-insoluble sizing materials may be removed with a

proteolytic or antylolytic enzynte. Thesc enzynres arc usually

ictive at temperatures up to 60"C., and 30-60 minutes at this

tcolperature wil l usually bc sufi icicnt to solubil izc tl]e sizes. Thcreor" lr lony rapid desizing agents availablc which wil l digest starcll

in 2-3 minuies. Sodiunr bromite desizing is also used.

Scourirg

Except lor lubricants applied in nranufacturing, PCDT polyester

fibre is usually clean and free from foreiSn matter. /The lubricants

can bc rcmovcd prior to dyeing by a wartrt wate\(71"C.) rinse.

Yar r rs and o t l rc r goods Inay be contaminated w i th d i r t o r o i l '

and a mild scour with non-ionic detergcnt and alkali (tetrasodiumpvroDhosDllatc) should bc used. lI the material is extremely dirty

oi "ont"i ir oii or grease stains, it is advisable to scour with 3

Detroleum solvent t ltat has been emulsif ied with a non-ionic

enrulsifying agent. Alkalis, such as tetrasodium pyrophosphate'

trisodium phosphate, sodium carbonate or sodium hydroxide

should be used with the petroleunr solvent for best results'lf thc PCDT polyester f ibrc is blended with other man-made

or natural f ibres, the ustlal scouring or bleaching ptocesses used

to prcparc the otl ler l ibre wil l not normally aflect the PCDT fibre'

A thorough rinsing should follow any preparatory treatment

to ensure that residual chenicals or foreign matter have becn

comnle te ly removed,It is advantageous to boil ofi or scour rnany fabrics in open

B : S Y N T T I E T I C I I I B R E S

width form bcfore proccssing in rope fornr. -l-his

trcatnrcrrtpartially stabil izcs thc goods and hclps to ptcvcnt cracks orstreaks, Carc should be takcn, however, to v;id fix t ion of itnyidentif ication tint that might be prescnt in thc goods.

Miscclltncous

Blcnd fabrics containing pCDT polycstcr f ibrcs wil l withsti l)dall the usual lreatmcnls cncoutrtcrcd in rnil l proccssing. I3y con-trast with PET polyestcr l ibrcs, PCD-l' polycstcr i ibrc.s rvil lwithstand kier boil ing, ancl this proccss nray bc uscd on blcuclsof cotton and PCDT fibrcs. Mcrcerizing wil l not allcct pCD.l.polyester l ibrcs, so long as thc tenrpcralurc of lhc causlic solutionis kept at 32.2'C. or lowcr.

. I l lc_nds of PCDT polycster f ibre and wool nray bc crrbonizc<J,but they should bc ncutralizcd as soon ts possiblc attcr baking.

l lcra-Sctl iug

Fabrics.of ICDT polyestcr do not requirc hcat-scll ir)g, Firbricsshould bc l lcat-trcirtcd to rcnlovc rcsirlurrl carricr aftir t lycirrg.'I 'he

tinre and tcnrpcrirtrrrc rcquircd to rcnrovc thc clrr. icr vtrric-swith type of carricr used. Nlanuf cturcrs' instructions shoul<l bcfollowcd closcly.

BI€nclri| |g

PCDT polycstcr f ibrc is prodtrced as r whilc f ibrc wlrich docsnot norna l l y rcqu i rc b lc lch ing . ln b lcnds w i th o thcr f ib rcs ,however, bleachirrg rnay bcconrc neccssary, and any of thctcchniques uscd to blcach the contplcmcntary fibrc nray bc uscd.

PCD"| polyestcr blcnds havc bccn blcachcd by both'batch andcontinuous rnethods with hydrogcn pcroxidc. Sodiunr hypochloritcand sodium chlorite nray also bc uscd to bleaclr blcntlcd fabricswilh no i l l elTect on thc ?CDT polycstcr f ibrc.

I t i s common pr i l c t i cc to in rprovc t l t c wh i lcncss o I b lcnchcdf i lb r i cs w i th thc a id o I var io r rs b l t rc and/or v io lc t r l ycs o rpigments, optical blcachcs or whilcncrs or conrbinations oi both.Optical brightcncrs lhat producc good whitcs on ccllulosics havclitt le or. no efcct on PCDT polyestcr f ibrc. Expcricncc hasshown that a comtrination of two optical briglrtcricrs. onc forPCDT and the other for thc ccllulosic fibre, protlucc gootlwhiles.

3 i 8 319

I I A N D B O O K O F T E X T I L E F I D R D S

DJci t lg

PCDT polycster fibres may be dyed either wilh disperse orazoic (devclopcd) dyes.

Dispersc dycs provide a conrplete rangc of shadcs frompastels to blacks. Azoic dyes are most comnronly used to produceblacks.

In conrnron with other iypes of polycstcr fibrc, PCDT polyesterlibres requirc the use of temperatures above the boil, or ofcarricrs.

CarricrsBccause of a lack of prcssurized equipment, nlost dycing isdone with the aid of a carrier. The proper selection and useof a carricr is importflnt. The self-enrulsifying butyl benzoatecarricr is suggestcd for knitted and woven fabrics. This materialhas low loxicity and produces level, well-penetrated dyeings.If the product is properly formulated, it yields a stable emulsionmercly by adding warm water while stirring vigorously.

Biphcnyl carriers are widely used for dyeing crrpcts of PCDTpolycstcr fibres. Thcse carricrs should be used according tomanufacturers' instrtrctions.

Emulsions of mcthyl salicylate have also given cxccllcnt rcsults.A largcr conccntration of this carrier is neccssary, however, toproduce dye exhaustion comparable with that obtained withbutyl benzoate. For this reason, methyl salicyl4te is more expen-sive to use. I

I I ig It Tenr perot ura Dyei ngA reduction in both time and chenrical cost may be obtained bydyeing PCDT polycster fibre under pressurc tt clcvaled tenlpera-tures. Tcmperatures of up lo l2l'C. arc recommended. The useof a carrier is necessary to obtain complete exhaustion of thedycbath, and the butyl benzoates are particularly effcctive.'l 'hc hcat fixation proccss for dyeing polycslcrs is espccitllyeffective in the rpplication of dispcrse dycs Lo PCD-| polycstcrfrbres and to blends of these fibres with ccllulosic libres.

PCD'f Polyest cr I Ccllulosic IllendsBlcnd labrics of PCDT polycstcr fibres with ccllulosic fibrcscan bc clyc<l in a one-bath proccclure using dispcrsc dycs on

380

A : S Y N T I I E T I C F I N R E S

tlre polycslcr fibrc and aftcr-trcatcd dircct dycs on thc ccllulosiclibrcs. ,llolh. classcs.ol dycs, ll lc carricr ",,,t iny n"."rr,,ry nrir' ir.tanls should bc addcd to rhc dycbulh a[ rhc sr;rr "iifi" Av"i,"cycre.

. In cases whcre lastncss rcquircmcnts ctnnot bc nlct willl aftcr-trcated. dircct dyes, a two-baih cxhaustion tcchniquc ",,,r'L'";r",Ito -anply . ,vats , nrp l r tho ls , su lphurs, so lublc " " , . , j , i f r r " * ,o i " "dycs to lhc cotton or ravon. .l lrc pCD.f polycsrci lt-br; l;;;;;f i rs t wi th d ispcrsc dycs. : fhc ccor ra.yon, i" rr,"n a y!J- I n- n,,;.'11"';l"illl:'J,,[tl?.;lli"i,ffi::i]

for thc spccific dyc uscd.

,.Thc dycr slrould usc the scqucncc o[ nlclhod bcst suilcd tonrs own equrpmcnt whcn handling l,CD,l. polycstcr/ccllulosic

blends. The polyesrcr fibrc nray bclyccl by r1,";;;ri;f;;;i;;;,the heat-fixation pro""ss o, uui"on b" a y"i .on ; ;;;i;,,;;,;;';:; Jl,.,ii T.;"f l'i"..,i1,?:',,"; ;T:lla I:rtcr tinrc. If rhc corron or ra-yorr is r" r,.-iv..ti'irliii'"l,ir.

;:illi:l',,:":i,lil,",""' )ll:"J:[* *:,;;l* .kilk' iiiscouring nrust bc carriccl out "tt.r. tl," ,".oiil .f r"f ,,*""i"r,i r""PC D7' I,olyesruIlVoo! DlcndsPCD' f . po lycstcr f ibrc in b lcr rds wi t l r wool cr r r bc t lyct l by c i thcra one-batch or two-batch mctho(n) en rs. rhe pcDr por ycsrcr n,j;"' ll"lilir ;l,l"lil;::J""rj,J:.:-[""r:*'

with nculral-dyci'g acicts, ctirorrrc "," pi '""i"t., r i j ' . .,,r

. Dispcrse dyes wilt stain thc wool to various dcgrccs. Ctrrcftrl

iJril.'J1t"Trli"r:ecessarv ro mini.tizc thc st.i' aticl uot irrrpaii

""1,,"^fi '?;:'*fi ":*1,,,"i: li.:iifl "':,,11." ::'i::l;:,lTi,fl:9l*9"1h" mcrhod is uscd, lhc dycs for ltrc *";i ;l;;;,t,i

'i,;sercc tcd l ro t | l lhosc t l la t w i l l t l yc l r t lhc s l igh t ly ac i t l cor r t l i t i o r rll:"1 {"1 alplying <tispcrsc <tycs orr rtrc iufV"rr.. nLr". if,"ncur rar dyc tng prc rnc l r l l i zcd dycs c i rn bc uscc l to p rov i t l c t r rc r r .swcar ras tness l ) ropcr l i cs . I f co lours b r ig l r l c r lh l r r r lhnsc ob l ; r in lb lcw j l l l t l l i s .c lass o f dycs arc rcqu i r .cd , l l i c rc " . " " nu , , , f r " , u i * , "1 , ii r c r<r uyc tng n l t l l tng ( l ycs l l ta t ,n : ty bc t rscd . Sr r r l l i t ( ld i t io s o fln r rnor r iu | | r su lP l ru te n r igh t bc nccr tc< t to a i t l t l yc ; * " - , ; , J ; ; ; ; ; ,u rc woo l i l c r lhc po lycs tc r f ib rc h ls bccr r b roUgt l l lo sh ( l c .

3 8 1j

r--l i I , l ' l ' l ' l | ! . ! '- l .-l

L- n .-.._..- n . . . . . . . - . . - - - -I I A N D B O O K O F T E X T I L E F I B R E S

The wool stain may be clcared by treatnent at 60'C. for20 minutcs with thc following:

Non-ionic detergent 2.0 Per cent.Ammonium hydroxide 1.0 Per cent.

The reducing nrethod oI clearing is usually unnecessary, asthc clcarccl wool will pick up dye fronl the polyester during thervool dyeing.

lf it-sbould be necessary to use the reducillg nrethod, thefollowing formula nay be used:

Amnoniurn hydrox ide 2 g. /1 .Sodium hydrosulphite 1 g./1.Non-ionic detcrgcnt 2 g./ l.

Trcat at 54 'C. Ior 30 n) inutes.

It optimum fastncss is requircd, a two-bath procedure .shouldbe usci. After applying the normal procedttre for dycing 100 pcrccnt PCDT polyestcr, the fabric is scottred to clcar the stitin onthc wool. Rinsing and then dycing in a new bath will give thedcsired shade to thc wool.

StrippingWhen imperfecl dyeings arc obtained with PCDT polyester {ibres'the following approaches should be considered:

1. The shade, in some cases, can be levelled by placing thefabric in a bath with the original amoun\ of carrier plusadditional dye to correct the shade if ncccssary.

2. The problem of shading in the fabric can also be solvedby reheat-ietting the fabric at a higher temperature than thatoiiginally uscd prior to dycing. Fabrics unevcnly heat sct inthc bcginning cannot bc dycd level unlcss unifornr lteat is appliedduring reheat-setting. The reheat-setting lemperature must behigher than the original heat-setting temperature. Streaks, spotsoisinrilar fabric defccts not causcd by the original heat settingshould not, of course, bc re-heat sct

3. The dycing nay also be strippcd as uruch as 50 per centby treatrncit in a bath containing l0-15 g./litrc butyl bcnzoalecirricr, plus 24 g.llirre of non-ionic detergcnt. The goo<Is shouldthcn be rinsed and redyed in a ncw bath.

4. l[ none of the abovc nrethods is successful, thc dyeing may

3 8 2

A : S Y N T I I E T I C F I I ] R E S

be stripped alnlost completcly by thc following trcrt lcnt forone hour at 82-93 "C. :Sodium chlorire l-4 g./1.Formic or oxalic acid l-4 g./1.'Tanalon Spccial' l-4 g.ll.Rinso thoroughly and ncutralize.Notc. This slripping formula must not bc uscd on fabricscontaining wool.

Shcaring

l1:yg i: commonly carricd out on pCDT pol ycstcr / rvorslcd,PCDT, polyestcr/woollcn and sonre pCD.f ply"rr.r7."li ,f ,rri"blend fabrics. Shcaring-fias I significant "n".t ",, if," .fip."i""..,,penorrnance and I)audlc oI thcsc fabrics,

Fabrics with a fuzzy surfacc rcquiring r clc n, sn)ootll finisllc(lappcnr ncc should f i rs t bc shcl rcd ar lc l lhcrr s i r rgcr l . S l rcnr i r r t trcnrovcs thc Iongcr librcs wlriclr worrkl ottlcrwisc rrrclt arr,l fnniilargc .bcads dur ing s ingcing, g iv ing r l rc r " f r r i " " i , , ,^ i i l , " " . i l " .)ncanng atso rncrcilscs tlrc pill rcsistitncc of tllc fabric.

Singcing

Singcing may bc carricd orrt wilhout dil l icully on fabrics con-laining PCDT polyester fabrics, rcsull ing in i,,,r iror"O nrrir""r",i."oue to a c ie tncr sur facc . As ind ica tcd tbovc , i t n l ry 6c ac lva l -lageous to sbcar the fabric bcforc singcing in orclci to rcmovcthe longcr l ibrcs.

.Cas-flame singeing or plate singcirrg nray bc uscrJ clTcctivclv.ao ;usrment i lo r op t imurn cond i t io r rs bc ing m: r t l c on " " " j il norv roua l mach iDe. Low fabr ic spccds r rnd /or h igh l lanrcs shot r l t lbc avojdcd, as i scvcrc slrcn8tlr loss-rna v,rcsrrl l. fr6rrr ou".ri, ig""i,,g,Spccc ls o f a t Ieas t 67 .5 r t r / rn i r r (75 y r l / rn i r r ) a re ,cco , , , , r rc -n , l c i .. Me l ted f ib rc -ends rcsu l t ing f rom s ingc ing w i l l , t v " uo t i . " "U iunef lv re r by cxhau-s l . (cchn iqucs than t l t c r ro rnrn l i ib rc s r r r f l r cc .and s tngcrng shou ld bc c i r r r i cd ou t n f tc r dyc ing in o r ( l c r to vo id1 :ry:kl"g elTcct. Frbrics dycrt by hcar-fixaiionincrhotts, tiowcv"in t r y bc s rngcd p r i o r t o dyc ing .

Chcrl ical Finishirg

Chenrical linishcs are usccl on blcnds of pCD.f polycstcr librcs

3tJl

I t , \ N D t ] O O K O F T E X T I L E F I B R E S

with other fibres, notably ccllulosics, to modify handle and impart

spccial charactcristics. These finishes may be resins, rcactants'

antis(atic agents, softeners, water repcllcnts or combittations of

such products.

Mcchnnical Fitrishing

The handlc of PCDT polycster blended labrics may bc altercdsigni0cantly by rncchanical f inishing, wlrich may or may not bccarricd out in conjunction with chcrlical {inishiug.

Colen<leriug

All types of calenders, e.g. polishing, Schrcincr, cmbossing and

silk calenders rnay be used lo good advantage. Calendcring may

be carried out in any of the following stagcs oI the chemicalfinishing operation: (l) before thc resin finish is applied, (2)

bcl.wccn thc drying and curing opcrations, or (3) aftcr thc curingoperation.

Seni-decotizing

This stcp may be carried out in the nnal stagcs of thc finislringprocedurc, giving additional crispness and snloothness to the

fabric.

sion shrunk to ensurcluxurious handlc whichfinisbing deviccs.

d imens iona l s tab i l i t y , and to p rov idc ais not obtainablc with olher nrcchanical

Cotnpressive Slfinkoge \All fabrics of PCDT polycstcr/cotton blcnds\l lould bc compres-

STRUCTURE AND PIIOPERTIES

The properties of PCDT polycstcr fibres are generally similarto those of PEI' polyester fibres, but tlrcrc are imporlantdiflercnccs, for exantple in mechanical properties, spccific gravity,etc. The information which follows in this section is bascd ttpotldata for thc PCDT polycster fibre Kodcl 2ll.

lr ine Slructurc nnd Appcarancc

S nr ool h -surfaccd f ibre of rottnd cross-secl ion.

I

384

" l f - l r f ' l

385

B : S Y N T I I I I T I C F I I ] R E S'I'cnacily

22-26.5 cNltex (2.5-3.0 g/dcn)

lil0o g:t t ion

24-34 per cent.

Iilastic I'ropcrlics265. cN/ tcx (30 g/dcrr ) a t y ie ld poi r r t (c t ' . J5J cN/rcx; 40 g/ t lcr rfor l 'E ' l ' [ ibre) .

-

Averflgc S(iftncss

97 cN/tcx (l I g/dcn).

At eragc Tougbncss

0.5 grams pcr cm./dcn.cm. (cf. pET polycstcr: 1.04).

Ilcsilic cc

Work rccovery perccntagc at 2 per ccnt cxtcns ion: g5 955 pcr ccnt cxtc [s ion: 5t ) 6( ]

l0 pcr ccnt cxtc s ion: 30 .10PET polycs lcr arc 75 85, 15-45,(Corresponding figures {or

ts-zs.)

Spccific Gravity

t .23 .

Ellcct of Moisturc

Ilegain: 0.4 pcr ccnt.

l'hcrrnnl Propcrlics

Melting point: 290. C.

Flantnwbil ity: Yarns and fabricsrlntcrial mclts and drorrs o[I whcnfibrcs nrust bc consiclcicd.

l i l fcct of Sunlight

Exccllcnt resisltncc.

burn s lowly, but thc burn i r rghanging f rcc. In b lcr r r ls , o thcr

II

r ' t l r ' t . ' - - l

t t t F . F . t F . F . F , l - , l ' : f ' , I , t r F : tI i A N D B O O K O F T E X T I L E F I B R E S

Chcmical Propert ies

Excellcnt resistance, comparable generally to PET polyestcr,including high resistance to acids and alkalis.

Dflcct o[ Organic Solvcnts

Excellcnt rcsistance to solvents and cleaning agents commonlyencounicrcd in nornral texti le usc. Trichloroctlrylene andnrcthylene chloride may cause soms shrinkage, and should bcavoided. The fibre is swelled by phenols, toluene, ethyl acetateand acctonc. It dissolvcs in a 60/40 mixture of phcnol andtctrachloroethane at 100'C.

Insecls

Similar to PET polyestcr.

Micro-organisnts

Similar to PET polyester.

I'CDT Pol),cster Fibrc ('Kodcl'\

386

w3.O

. i2 o.9o l ' 5

F t o

5 1 0 ! 5 2 0 2 5 . 3 0STRAIN (% ELONGAIION)

i l

Gcncral Chlraclcristics

PCDT polyester f ibres havc a gcneral rescmblancc to pE-fpolyester f ibres, but the difercnces are suclr as to cxcrt a signil i-cant elTect on the uscs of the fibres. pCDT polycslcr nUr"sjiou"lower- tcnacity and clongation than thc pEI'poiy"rf., f i frr"r, 'Ui,tthcy havc supcrior rccovcry fronr strctch. 1.hcy scrvc in rl,ptici i-Irons whcre rcsil icncc arrd bouncc arc of grcit lcr irrrporilncclltan high tcnflcity, c.g. in cllrpcts, rugs, knitwcar, ctc.

. . l .ho towcr tcnac i ty o f thcsc f ib rcs cont r ib | | t cs to lhc i r in rp rovcdpil l ing propcrties. Fabrics wil l shcd thcir pil ls nrorc rcacti ly itr l i ifabrics nradc fronl the stronger polycstcr hbrcs.. - lhc mots tu re absorp t ion o f PCDT po lycs tc r f ib rcs i s v i r tua l l vident ica l w i th thar o I rhe pET po lyes tc i f ib rcs , and r f r i s n f l cc r i i i i lbchavrour.o[ thc PCDT polycstcr l ibrcs in a sinri lar rvry. .fhcn lcc r r : ln tc l p ropcr t i cs a rc no t a f l cc tc ( l by rno is l r t rc ; t l t c c lcc t r i cn lpropcrties arc exccllcnt; thc accurnulalioir of clcctrostutic ch:rri isnray cause dil l lcult ies.

PCDT polyester f ibrcs have a lowcr spccil ic gravity than pE.fpolyestet

. I i brcs, giving them iocreased coucring pow"r, Tlrcyprovide. l ightweight fabrics oI grcat warmth and con)fort.. . I ne nrgh meltrng point of PCDT polycster f ibrcs makcs for ahigh safe-ironing temperature labotit i tA.C.).

.Fabrics.containing pCDT polyester f ibrc may be hcat-sct irt a

rc rar rverv tow lenrpcra ture , c .g . about 160"C, , and th is i s n r r t i c_u la r ly usc lu l iD the f in ish ing o [ b lcndcd fabr ics conta in i r rg woo l .

B : S Y N T I I E T I C F I D R E S

PCDT POLYESTER FIBRE IN USE

IVas[ing

Similar to PET polyester f ibrcs.

Dryirrg

Similar to PET polyester f ibrcs.

lroning

PCDT polyester f ibrcs may be ironed safcly at tcr.npcraturcs upto about 218 'C.

387


Dry Clcanirg

Trichlorocthylcnc and mcthylenc chloridc should not be used

in dry-c leaning PCDT polycster f ibrcs, as lhcy may carrse

shrinkage. Percltloroethylcne should be uscd wilh care'

trnd Uscs

A pporal Fabrics

The cxccllcnt rccovcry lronr strctch and high resistancc to pill iDg

have bcen intportitnt Iactors in lhe acceptance oI.PCDT.poly-estcr fibrcs in thc apparel fnbric field. Illcnds with wool arrd

acrylic or moclacrylii hbres are parlicularly . s-uitable for k-nittcdgoocls, providing good dinrensional stability' ease-of-care,Iomfort ind rxarmth, together with the characteristics associatedwith polycsrcr fibrcs gcncrally. Swcaters, for cxamplc, aremachine rvashablc and drYablc.

Floor CoveringsThc cxccllcnt rcsilience and rccovcry of PCDT polyestcr librcshas stood them in good stead in the lloor covering field' Rugs'nrats and broadloom carpets are made from 100 per cent PCDTpolyester llbre. They are soft, luxurious and hard wearing, withpood resistance to matting and clumping.

Fibcrfil lTbe low spccific gravity of PCDT botyester Iibres.-is a uscfulcharacterisiic in applications such as pillows, quilts, padd-ed

clothing ancl the li[e, where the fibre is used in the form of a

fiberfil i Low spccific gravity is not nccessarily thc most inlportantoropertv of a'fiberfil l nratirial, howevcr. PCDT polyester fibre

iras'ouistanding resiliance that permits it to support the voids

witlrin the nberfil l batt.

(3) OTHER TYPES OF POLYES-|ER FIBRE

Since its introduction during the early 1950s' polycthylerre tere-pt',thnlot" librc (PET polycstcr fibrc) has nradc.r'rpid lrcadwayanrl attaincrl a clominating position in the field of synthetictcxtilc fibrcs- PET polyestci fibres arc now bcing produccd by

A : S Y N T I I E T I C F I B I T [ S

nrany firnts throughorrl. thc workl.PE1' polycster f ibrcs have rcachcd this position, rs irr t lrc casc

oI ny lon 6 .6 and ny lon 6 , by p rov id ing t l i c tcx r i t c u , "n r i , " , r i " ,w t th l ib rcs tha l servc e l l cc t i ve ly ovcr : r w idc ra r rgc o f tcx t i l c nnr . lrndus tna t app l i ca t ions . Dut , incv i tnb ly , t l l c rc t rc f i c lds o f anr r l i c l l -l ron in wh ich . the rangc o f p ropcr t i cs o l l c rcd by I ,D . f p ; l ycs lc rI rDrcs i ! rc In i ldcqu l l l c o r r rns i l t i s I c to ry . A d l i l ) rc r t l i l nUf i t c t r t rc rshavc souglrt ways of produciug ncrv tylrcs of polycstcr f i lrrc ; l l ; l ;would rctain thc broad charactcrislics associntcj witl l polycstcrs,but providc fibres capable o[ scrving whcrc cstablishcj potycst"iI ibres are inadcquatc.

As inthc case o[ polyamidc fibrcs, tttcn]pts to provirlc ncwtypes of polyester f ibre have followc<l thrcc main roulcs:

(A) Physical modi{ication of cstablislrcrt typcsfibre.

(13) Clrcnrical nrodification of cstablisllcd typcsfib rc.

(C) New typcs oI potycstcr.Already, as we huve sccn, thc third routc hrs Drovirlcd a ncrv

typc of polycster fibrc, PCD'f polycstcr, which has bcconrcestablished on a comrnercial basis a longsidc ,l,E I' polycstcr [ibrcs.

(A) Pr'lysrcAL MoDlFlcATroN oF ESTAIIL|SI.IEDPOLYESTER TYPES

Modif icrt ion of PolJ mcr

The mcchanical propcrtics of polycstcr fibrcs nray bc vrricd bycontrolling thc physical charactcristics o[ thc polynrcr. Itcductionof the molecular wcight, for cxamplc, will allcct the ntcchanicrlproperties, and this is used in producing polycstcr fibr.cs withreduced pill ing tcndcncics.

The or icntat ion and crysta l l in i ly of thc polymcr n lay bc a l lcctc( lby adjustment o[ thc conditions uscd in drawing thc fibrc. Two_stagc drawing, for exanrplc, is uscd for thc production of highmodulus polyester staple which is suitablc for blcnding witlrcot ton,

Control of thc drawing process also makcs possiblc thc pro<tuc-tion o[ filanrcnts in which thcre are seclions of drawn nralcri:rl

o f po lycs tc r

o f po lycs tc r

388 389

- 1 - - l - _ l - t - l l - t - 1 1 t ' l ' l . I I ' r I ' r I r I r [ ' r ' l 11

t " t t t t t t t E E E t n t I n t n t n tI I A N D B O O K O F T E X T I L E F I D R E S

alternating with unclrawn material. This thick-andlbin type of

filameot gives attractive dye-fleck eflects'---itr" sht]nk^g" of f i lamenis is influenced by the drawing process'

""i i i , l . i t ur"i in th" production of yarns which provide special

surlace effects on fabrics.

Modificrtion of Filrrc

M ultilobal C ross-Section

As in the caso of polyamicle fibrcs, polyester f ibres of special

cross-scctiorr may be made by extruding the f ' l laments tbrough

holes of appropriate shape.

Bulk Staple

Dillerential cooling of the fi laments as they emerge from. the

spinncr"t protluces a spiral ellect in the fi laments' This technique

is uscd in producing bulked polyester yrrns'

Textured and Bulked Yarrts

Polyesters are thermoplastic, and the l ibres may be subjected to

all the tcxturing processes rn common use'

Bicomponent Fibres

Bicomponent l i laments are prodtrced from polyesters,.with eflects

similai to those obtained frorn bicomponent polyamide yarns'

(B) CHEMICAL MODIFICAT/N OF ESTABLISHEDPOLYESTER TYPES

Tbe polyesters from which PET and PCDT polyester fibres are

spun-arc chemically inactive materials, and this has.been- an

important factor in the di{Iiculties associated with dyeirrg these

frbies. There ate no active Sroups in the polymer molecule to

which dyestulls arc attracted.Much of the rescarch on polycster f ibrcs during recstlt ycars

has becn concerncd with this problem of improving the dyeing

iira.i"t"risti"s of the Iibre, ond ptog,"st has been made by

modifying the chemical natttre of the polynrer molccule' Special

tuo"t bt -PfT

polycstcr ftbrcs are norv produccd, for cxarnple, it '

ihiclr sulphonic iroups havo bcen introduced iDto tl lc polycstcr

390 391

B : S Y N T I I E ' I ' I C F I I ] R E S

nro lccule, prov id ing s i t .cs . to wl r ich basic t lycstuf fs r r ray bccorr rcsncrrored. l . l r logc s or phospl lonatc groups subst i tu tcd in t l lcporymer s t ructure enl lance t l te narne retcrdar)ce. esDcci i l l lv i fant i |nony ox ide is i r rc ludcd in t l le polynrer rnatr ix .

Amnity for dyestulls and other rnodi0cations to the fibrcpropcrtics are nlso bcstowcd upon pE'l polycstcr librcs by intro-ducing a sn la l l arnount of anothcr contponcnt in lo t l rc poly_rr rer izat ion. A f ibre 'Gr i lcr rc ' , fo l cxrn:p le, was r r rade by NipponIhyon Co. .Ltd. by condensing tcrepht i ra l ic ac i r l , e thy lc lc g i ico l: l lo 1 ,Tu, l , a lount . o ' p .hydroxy bcnzoic ac id Lo forr : r a poly-ester /polyether copolyrner .

(C) NEW TYPES OF POLYESTER'l'hc

n)ost radical wly oI prorJucing polycstcr librcs with dillcrcntranges of propcrties is to spin the fibres fronr ncw typcs oIpolyester . Poly-p.e lhy lencoxybcrrzoate, for cxanrp lc . l , i ,s b.c , rWun r r ) to l lDres whic l l wcre l l tarketcd in J : rp; rn a i A- . l .c l l . l , ro_r luced ty react i r rg et l ly lene ox i r lc rv i t l r p- t , y i t ru*yt r . ur , , i . ' " . i , f .t l lc po lyn ler n lc l ts a! 224oC and is r : re l t ipu, r . ,1 .1,"

l . ib ; . , ' ; ; ;,_il ' i l lr i ' l _rlany respecrs to I)E'l polyestcr'nbrcs. t.elccliv' i i35_.32-46.80 cN/rex (4.0_5.3 gi,t"i,y, "to,,giriou- "f-ii i"u'[I5-3070, rv i t f r a l r r rost IOA' /o rc iovcry" t o , , , ' io* " f " " " , i i io , i .Moisture reg,rirr Q.4,i/o and spccitic grav'ity 1.34 ;;; ,;;:i;;;i i;;to those of l,ET polyester fi-bres. l{eiistaricc to o.i,fs u,iif ,ff."ii",rs greater t l )a

that oI PET polyestcr f ibrcs.roly-p-e rylelleoxybcnzoatc fibres, rcscrrrblilrg closcly thcestaDi ls t lcd potyestcr { lbres, wcre unablc to of tcr ar lva l taucs

uraL n] lg l t t . t ravc. g ivcn rcrn a worthwhi le p lacc i

thc tcx i i lcn larKet , and product ion rvrs d iscont inucd.

I I A N D A O O K O F T E X T I L E I ' I I J R E S

3. POLYVINYL DERIVATIVES

l!r(roduclion

It has long bcen known tl ')at cert in compounds containing a

.f""frf" ft"ri t rvoul<l unclcrgo spontaneous change, during which

: r l ieLr id , fo r cx l t t tp tc , rvas co t tvc r tc t l g r d t r l l l y in to a . so l id

nrn t " ' r i r t . ' t

t t " low-bo i t ing l iqu id v iny l c l t lo r i t l c , n rorc th i rn a

ccr t l r ry i rgo . was shown to ch i lngc i l l th is way '' lhcse cltatrgcs arc tlow lccogtlizcd as polynlcrlzil( lons' otlr l l lg

rvhich thc smill molcculcs join togcthcr via tlre double bond to

fornr long clrain trtolccttlcs of l lolyntcr. lSr:c bclo,w') -,-Cornnounds cont l in i t tg the v iny l g roup, i c ' CH"=CH- ' w t l l

conrmorrly undergo potylne rizat iotr in t l l is w y, ntl thc polylncrs

il i" i nr" 'fo'nt"tt-arc

ialletl polyvinl ' l cotttpotuttls' -the l inking

rosc t l l c r o I l l r c sn ta l l t l ro lcc t t l cs o f a v iny l con)pound rcsu l l s l r l

thJ fornration o[ a long nroleculc consisting of calbon lttonls'

t l)c rerrrrining atoms that werc prescnt in the vinyl compoul](l

PO LYM EI I , IZ-A' I ' ION OF VINYL COMPOUND

h:.g h:{ h:{

ffi+-$+-*392

- - l . [ " I " t r II

, - lI

' tI

- t ' - l - l ' [ - [ "-1 "-1

D : S Y N T I r E T I C F I I ] R D S

formjng pcndant g ror rps o f a ton ts a t t tc l t cd to thc lo r rq c l r rbonDacKDonc o l the po lyn tc r n ro lccu lc .

As thc . fo rnra t ion o f po ly rncr t i r kcs p lacc by l rc l< l i l i on o f oncsr ra t t n ro tecu le to ano lhcr , w i thoUt t l t c c l in r inn l ion o f rva lc r o rother nraterials, this type of rcaclion is an eddition poly,,t", i z,, i iui,,.P.oly.l inyl compounds wcre arr.tong thc nrst polyrncrs-to bcst.udicd asrolcntial sourcqs of synthciic f ibrcs. .f. l i"

".rlv C"li,,"ur rDrc ' f c .Cc '

wa-s n l r t l c by cx t r t rd ing so l r r t io r rs o f i r c i r lo r in : r tcdporyvrny t ch lo r idc . I t r , v i l s no t un l i l thc car ly yc l r rs o f Work l W rIl, howcr,,cr,- that polyvinyl conrpounds

-tcg,,,, io , l;r; ;"i, ip ro rnrsc , rn thc l i c ld .o f gcnu inc tcx t i l c f ib rcs . F ib rcs wcrc spun

r rom so lu t rons o t po lyacry lon i t r i l c (po lyv i r ry l cyar r idc ) , a ld t l i cscr r rvc s rncc dcvc lo l )cd in to onc o f lhc )os t i r l rpor lan t o f l r l l c l t rsscsof synthctic l lbrcs.

POLYACRYLONTTRILE, FI B IIES

Fibrcs spun lrom polyntcrs orcI{" =CI'I.CN --!

Acrylonitrilc

INTRODUCTION

copolynrcrs of lcrylonilri lc :-cl'r,-cH-Cr,rr-cH_i lCN CN

Itolyacrylonitrilc

Acrylonitrilc wls rnade in Cernrany by Mourctr in 1g93. Irronrthat tirnc, up to almost rhc outbrcak of Workl W,,, f f , ".iuionii-rilc rcnraincd laboratory curiosiry. Dur du;ing-ilr;' iri i; i; j i l.r r acqul rco a ncw status by becoming a const i t0cnt of onc of::]",1]-": ilp:.,;.Lr t{lT gf synrhc(ic rubbcr undcr ctcvctoprrclrlu uermat)y and thc U.S,A.

Dur ing Wor ld War I I , the synthet ic rubbcr industrv uDdcrwcnrn nushroom growth il thc U.S.A., and this prccipititcd a larec-scale nar)ufaclurc o[ acrylonirrile. By rh" ;,i.i ;i i;; ,;,,;. ';;i;_

rontt le wils ir rcliltivcly cltclp induslrial chcrnicll, ;rnrl w:rsava iluic lD targe (luantitics. polynrcrs of acrylonitrilc crrrrc rrndcrr r r rcnstvc rcvtcw ln lhc rubbcr , p last ics nud synl t rc t ic l ibrcindustries.Acry loni t r i lc undcrgocs addi t ion polyrner izat ion rcnc l i tv . ar rdporyflcrytonilrilc hlrl bccn cxamincd ts a polcnliitl fibrc_tointinc

l )o lyrncr drr r ing lhc la te l9 l0s. pract ica l < j i iT icu l l ic , 1 , , . f pr*" , , i " j

391

r l ' l ' l

I I A N D B O O K O F T E X T I L E F I A R E S

any substrulial progress beiug made jn lhis direction, howcvcr,the nrain problenr being to nod a way of spinning a polymcrrvhich was virtually infusible and insoluble in any of t lte solvetrtsthen cxanlincd. Al that t inre, attempls to spin polyacrylonitri lervcre directcd largely at prodncing ntore soluble copolymers, e.g.containing vinyl chloride, which would dissolvc in commonsolvents such as acetone. Fibres werc spun fronr tl leso copolymcrsby dry spinning techniqucs such as those used in spinning acetatefibres, and sonre of the copolymer fibres had propcrties ofconsiderable interest.

Shortly before the war, solvents for 100 per cent polyacry-lonitri lc were found, such as dinrethyl fornranride, and theexperimental production of polyacrylonitri le f ibres continucdthroughout the war years in Gerntany by I.G. Farbcnindustrie,and in U.S.A. by E. I. du Pont de Nemours and Co. Inc. l ly1942, du Pont rvcre producing a polyacrylonitri le hbre which waso[Iered to the U.S. Governrneut (or military applications. 1'hcevrluation of this polymcr rvas so promising that in l9{4 du Poniannounced their decision to begin pilot plarrt producliorr. l ly1945, du Pont were producing tlre world's I irst polyacrylonitri lcfibre, whiclr was provisionally named Fiber A.

Thcse carly polyacrylonitri le f ibres werc alnrost as siroDg asnylon, r.nd had a high resistance to chernicals (notably acids)and to sunlight. They rvere very dil l icult to dye, and it seemcdtlrat their most promising comnrercial outlets must l ie in industrialand outdoor applications. As dycing lcclrniques rvcre cvolvccl,however, it becamc apparent that polyacrylon itr i lc f iblcs couldalso become of importance in tlr/ apparel labrjc f ield.

In 1948, du Pont made plans for the largc-scale production ofFiber A. and in July 1950 a plant came into production at Canrdcn,South Carolina. The ftbre was produced as continuous fi lanrcntyarn, and it was given the trade nanre 'Orlou'. This first f ibrclvas a 100 per ceot polymer of acrylonitri le, and it sti l l presente(lproblenrs in dyeing, In due course, howevcr, thc introduclion oIsnrall proporlions of t sccond mononlcr providcd nrodificd fornrsof , ibre \ ', i th improved dyeabil ity.

In March 1952, a sccond 'Or lon 'p lan t a t Canrdcn began pro-ducing staple fibre-

l r l canwhi lc , in 1950. a sccond U.S. rnanu lac turc r cn tc tc ( l thcpoly crylon itri lc f ibrc ficld, when Chcnrstrand Corp. constructcd

394

B : S Y N T I I E T I C F I S I t E S

a pilor plantr f 'his was followc<.l by a conrnrcrcial l) l irnt lvlrich

Tlr""Jdlliil i'r3"",lill i,lli"ll:,i':,:1,1""1,',i;x;:ll,*ill

iiff : [ ]ffi# *,i;i';l T;ll,';1 r ll, "'m;i**f xi,?"]l Ju:".""u'Acrilan'

pt:r nr wrs opcucd i r Cotcrainc ;,, N;;it,";;;

,^ O"y-r-,,i.*_ the pcriod 1.955-60, polyacrylon ir rilc fibrc plar)ts bcla

ir!d,!ll:,.:: " i: : Tii ::i li: 1,"J1,1".o :: i:il J ;, i J1T j,:lli,",X,j''l:, 1:oJ:.r:",ltucri

on ner d. si rrcc rhcn, ",:;;;,;i;;, :;ii i;ii;

Polyacrylonitri lc f ibrcs are now proclucccl by tnrrry ntrlul. irc-

1"1:'i,,:?f; c;,,i

;;l; ";l;i:ir",,", lratrc';r rncs - r\r "';' " i; ;;' "i ; ;,;;

t t' n-i": r' ;liLi il :i l livi l'"'*'l' l'ill':' ll ̂ ":o# l';:?*"r'"",,:.3ffi

'u'T''""1';'l'i;,'iff : :i J:ii:,t,Ji:::i;,,:i ni?i,e::{fj :ij:fJ,jff;::i:,i :;i} ill $x:t,,':i*,,"Ji:.,1t::':",t"f ,,1SJil'rt".ti,Tiltii',f,'ii,J",;i:: rcspcct, it i' n'o'" JlrriJi iocasc or. poryanjde or porycsrcr l.

ns 'r Scncrnl class th.rr irr thc

,""1'"#';';1:1",1i1'",it,,1$ti9"'"nitrirc tibrcs' rrrcrc was i,,oo' b".o,n " of p"-r-",,i,' ffi ;";:' :i "t1',,t,,?,T;tTit".lrlffi ;,,,jt":::ff ',x'i?:[ -,i3$t,li["T:t;:lii*;iilJl':i:f xti;?ii:1,!;l"fl,jilii' which nbres oi si,ritar "r'"'i'i"'i'ii.' "",,ii^ This. problent rvas considcrcd by lhe U.S. Fcdcrlrl . l-nrrlc

FlJll''i:Tl;:'^li::,'"Jilil,'1,::,11,:',lli: lii:: X lililr: l,:ll

' t " t 'p t rs ot ; I 'oLyAcRyLoN I . f R tLI : l i lBRt i

395

I I A N D B O O K O F T E X ' I L E F I B R E S

Polvrcrvtonitrile fibres were subdivided into two classcs, dcpcnd-ing-upon lhe proportion oI acrylonitrile in thc polyntc-r- (scc

lr"'io*). Thos" iolyacrylonitrile fibrcs containing at lcast 85 pcr

ccnt of acrylonitrilc units arc describcd as ocrylic fibtcs, wherca;those llbrcs containing betwccn 35 and 85 pcr ccnt of acrylonitrilelic rlcscribctl as rrtorlccryfic fibrcs.

'this subclivision is hclpfrrl in lhat it scl)irrirlcs Iwo grorrps ofDolvacrvlonitrile fibrc which havc Iittlc itl contttrott frorn tlrcoracticai ooint of view. But it stil l lcavcs rootn lor great varifltionirr the characteristics of individual fibres within each group 'fhc

tcrm 'acrylic', for examplc, docs not distinguish bctween thcfibre whic'h is a copolynrer of acrylonitrile with a small proportionof a seconcl conrponent, atrd a fibre spun from a graft copolymeroI acrv loni t r i le .

A firrrhcr sottrcc oI cott[rtsiott ariscs front thc fact that lhc

olllcial Ir.-f.C. tcrnr 'ntodacrylic' rcfcrs to polyrlcrs containing35-84 per cenl of acrylonitrilc. It thus i[clttdes copolymcrs irrrvhich acrylonilrile may form the minor conlponent; a fibre spurlfrom a copolymer cotttaining 60% o[ vinyl chloride antl 40% ofacrv lo l l i t r i ic . for exr t t lp le , is r r torc proper ly cor)s idere( l [ ronr t l rec l rern icr l s tarr r lpo int a i a polyv iny l type f ibrc , dcspi te i ts F- ' l -Cclass i f icaI ion as r r l todacry l ic f ibrc

NOM ENCLATU RE

Federal Trude Cotnnrissiott Delinitioys

The generic nrmes ncrylic and ntotltlcrylic were adopted- by thcU.S.

-Fcricral Trarle Commissiorr for fibrcs of the polyacrylonitrile

class. -fhe dcfinitions are as follows:

Acrylic. A manufactured. fibre in which the fibre-forming sub-stancg is any long chain synthetic polymer composed of at leastS5 per ccot by weight of acrylotrilri lc units.

Moducrylic. A n'ranufacturcd hbre in which the {ibrc-forrningsubstance is any long chain synthelic polymer composed of Iessthan 85 per ceni but at leflst 35 per ccnt by weight of acrylonitrilc

uni ts- cxcent f ibres qur l i fy ing t rnder sub 'paragrapl r (2) of para 'qrapl i ( i ) ( r t rbber) o i th is scct ion ant l f i t - r rcs ( lua l i ly i l rg undcr-paragrrph

(q) (g lass) oI th is scct ion '

- 1 ' � -1 r I ' f ' l I I

396 397

B: S YN,T I I ET I C I , ' ' I IR I ]S

Nolc

Jn, t l rc scction which fol lows, polyacrylonitr i lc l ibrcs rrrc corr-srocrr,. t undcr two classcs, dcpcnding rrpon {hc proport ion oIacrylouilrilc units in thc polynrcr:

-(l) Acrylic Filr.cs, which arc spun frorrr polyrrrcr.s conrposcrlof irt.lcirst 85 pcr ccnt. by wciglrt oi acrylonirrilc iniirif". .l,rr"i_pondrr)g to the F.T.C. dcfinirion ot acrylic fibrc).(2).M9tla:crylic ,Fibres, which arc spun frorn polynrcrs conr_poscd oT lcss.t.han 85 pcr ccnt bu! t lcnst 50 pcr ccrit bv wcirhlot acrylonrtnlc -units (i.e. corrcspoDding to thc I..-I..C. rictirritiori

;l'l?1j,:",i:l,lj;i;,lJ'.}"j,:u'i,l "'lllili":",T,llffi I,,"",",1:Jcopolyncr).

, JIi

r l r l l r r

I I N D U O O K

(I) ACRYLIC FIBRES

Fibrcs sptrn fronr polynrers consisling of at lcast 85 per ce[t byrvcight of acrylonitrile units (-{H,-CH(CN)-).

TYPES AND SIZES-fhe

early types of polyacrylonitri le nbre, e.g. 'O rlotl 'Types 4l and81, were spun from l00 per cent polyacrylonitri le, but almost allInodcrn types of acrylic 0bre are spun from copolyn)ers Thescmay be the 'normal' type of copolyrner in which the secolldconlponent is polymerized with the acrylonitri le, or they ma1'be of the'graft ' copolynrer type, in rvhich thc sccond cornponctltis incorporated by grafting on to thc polyacrylonitri le

The nature and proportion of the second component used il lindividual acrylic f ibres are rarely disclosed, but a very largenumber of acrylonitri le copolynrers has becn described in thepatent l i lerature. Vinyl acetate, vinyl chloride, methyl acrylateitnd 2-vinyl-pyri(l ine are anrong the ntotromers which are

O F T E X ] I L E F I I ] I I E S

probably uscd comntercially.Acrylic fibres are used as filamenl yarn,tow lor

antl ai staple fibre. Staple is protluced in countssuitable lor all spinning systents.

(

Iligh Bulk Fibre

Acrylic libres arc unusual in their ability to attain a metastablestati on hot stretching. When hot-stretched libres are cooled, theywill rcmain in their strctched state until subsequently heated,when they revert to their unstretched climensions. High shrinkagehbres may be made in this way, with shrinkages of 30 per centand higher, and by blending these high-shrink fibres with normalstaple, followcd by subsequent steaming, bigh bulk cllects areobta ined.

Many types of high-shrinkagc lcrylic fibre aro now produccd.

convers lon ,and length

398 399

E E ll E E E l': f: f: f: f: f:': fr h H H HS Y N T I I E T I C F T B R E S

PRODUCTION

MottorDcr Sylrthccis

Acrylonitrile js available in rnr

ff iih.illTg,#'iL"J'";'ii,r,i'fi 1'"'ll;',il,,l;f ',lii",,ln l1:li,1;(a) nh1'lsna Cyanhyd n DelrydrctionEthylene cyanhydritr is nrade cit ltcr by trclttnrcnI of cthylcrrc

:ili.:;,;il,l lliJ?ff; """x1lL:,(/1, o. u, ;";'i;;i ;i ;ii;ii;;,,,ill',o:31ii'li" ;llllilt

,jl ;^ll:l':ll,:u (,iq,ri,r prursc) nr

.r 150"c. ir tr)c prescnce ot ",,,rlljlt rti"t'tsl' ot'(vaPr-rur phasc)

cH,-cH, + HCN

ETHYLENE OXTDE

@..rHO CH, -CH, " .r .*r^ /

ETI-IYLENE CHI.OROIIYORIN

A C R Y L O N I T E I L II 'rodrrction ot.Acr),lonitritc.

HOCltr cH, CN

E T I I Y L E N ECYANIIY{)RIN

Il oY

cH, - cHcN

' I A N D B O O K O F T I ] X T I L E F I I ] I I E S

(b) Acet;,leue mcl IICN

Acrylonitri le is rl l i lde direclly front acetylenc by the addil ion ol'HCN.

CH=CH+IICN-+ CH,=q11q1

(c) Propylcnc Roulc

Propylcnc is oxidizcd to acrolcin (l) which is thcn rcflctcd withanrnronia to fonn a hydroxy antino compound (2). This isdchydra(cd and dehydrogenated to acrylonitri le (3).

(l) (2) ,/NH.CI-1, :Ct1--911,-rCH! :CFl-CHO+CHr =CI-I-CH(O ft-

,/'1

(3)CH,=CFI.CN

\<J) Acct oldchyde Route

Hydrogcn cyanide is added to acetaldehydc to lorm the cyxnhy-drin (l). This is dehydrated to acrylouitri le (2).

cl{.cHo + IrcN9cH"cH<3$ 9]"", :.*r."^

s Y N' r '

c r tc

i

; '

\

Polynlcrizn(iorl

Thc po lynrc r iza t ion o f f l c ry lon i t r i le and i t s cp-monomer is com-r r ron ly car r i cd ou t by s l i r r ing the monomer( w i lh watc r in thepresencc of catalysl and surfactants. Sonrc of thc acrylonitri ledissolves in the water to form a 7 per ccnt solution, the excessrlonorner fornring an cnrulsion.

As polymerization proceeds, t lre polymer (which is irrsolublei|r rvatcr) is prccipitated to form r slurry.'fhis is l i l tercd, and thcpolynrer is washccl and dricd. ,

Polymcrization may bc carried out as a batch process, or ona continuous basis, In thc lattcr case, mononter, wrter and othcrnra(crials rc fcd into a rcaclion vcsscl, irnd sltt lty is withdrawncontintrously. Unrcactc(l rl lononrcr is rccovcrcd and rctutlred tothc oo lvnrc r iza t ion .

5 an 3 a E +d = E * E l

/6if$'t]t l,t t '-

\ - J 1 2 .

i i "z

t t Ht l 5

I LZ-YI t / * FI t t € ; l

f l - l l !i l \ . = +-l .!-r

400

r- -lI

- I

-11 '--l --l ,."1 -_1 'r-l 'l--f tr1

n n F'i |.,,i f'': 1"1 Fl - l"i F:. f''l Fi Fl n FI I ̂ N D I } O O K O F T E X T I L E F I I ] I I E S

Spirring

Po lyec ly lon i t r i le , 100 pcr ccn l o r cou la in i t rg t lp to l5 pcr ccn tco-rrononter, tends to deconlposc ou mclting, and fibres cannot

be produced by nrelt spinning processes ls ttsed lor polyatnide

and polyestel l ibres. Acrylic f ibres are thelclore pro(luccd fronlso lu t ioDs, c i ther by d ry o r \vc t sp inn ing

Dry S pinning-fhc polymcr is dissolved in an orgauic solvent, such as dimethylfornramide, to fornl a soltrt ion containi0g 25-40 per cent ofpolymer. This is degassed, hltcred and licated alnost to boil ingpoint, and then extruded through spinnerets.

Thc fine jets of solution en'rcrge into a vertical tttbe or spinningccll, throtrgh which air or oll ler gas at high tenpcrattrre (e.g.

400"C.) is f lorving. As the jets fall through thc tube, the solvenlevaporates 1o leave solid fi lancnts of polyruer'

' fhe fi lanrcnts are brought togcthcr at thc base of thc spinuingcell and strclched hot to 3-10 times their original length. If con-tinuous fi lament yarn is being prodLtccd, the l i laments are oiled,trvistcd and thcn wouncl on to bobbios.

lf staplc fibre is rcqtrired, a number of yarns are brotrght

together into a tow. This is then criulpcd and cut into staple

of thc dcsired length. Uncut tow is ttsed for convetsion.

lVrt S pituting

Polymcr is dissolvcd in din'lethyl [orl] lamidc or othcr solvcnt,and the solution .is degasscd and ft ltered. It is then punped

through sp innere ts in to a co i rg t r la t ing ba th gdnta in ing a l iqu id inwhich thc solvcnt is soltrbte but thc polyn{er insoluble. TIre jets

of solution coagtilalc into finc fi lanrents, fornring a tow wl]ichis washecl after emerging from the bath.'fhe tow is heated anddrarvn, driecl, oiled and crimpcd. It nay then bc healcd lo relax

the l ibre beforc bcing cttt into staple.

PROCESSING

Dycit|g

Thc car ly fo rms o I po lyacry lon i t r i l c f ib lc , such as 'Or lon 'Typc

4l staple and Type 8l l i lanrcnt yarn, werc dimcult to dye satis-

B : S Y N T I T E T I C F ] l J N E S

f lc to r i l y . Brs ic dycs wcre uscd, bu t l igh l . f i l s lncss w i rs noot . Asa l rs lac to ry rangc o [ shadcs was prov idcd , howcvc l , by n11f t i11p

||".31i:i,""n,o.'s ion lroccss tlcvclolccl irr l95t) ior ,i";i;;;;;;

1-he prcferred techniquc rvirs to nrtkc usc of ncicl dycs in thcp rcscncc ,of ̂ cul) rous ions. Thc proccss lras t"",, of gr""i u.i,," iu( | yc tng i l u t t b r cs b i r sc ( l on l r c r y l o r r i t r i l c ; t l t c co l )Pc r i t c t s i t s i rblidge which links rhe nitrile grout) oi rl," tiUJ" r" iii.';y;

nrolecule.

- Us ing the cuprous ion tcc l rn iq r rc , i t rvas poss ib lc to ob la infirs.t colours covcring a wiclc rangc on ,Oilon, stlrnlc l ibr.c-l lthough the rnorc highly oricntatcd conrinuo,,, frf u,i i", ' i i-.O.iou:

l : : , ' l 9 l oy" so rcad i ty . Cood resu l ts wcrc ob t i r inc (1 , l lo rvcvcr ,

oy-_ayellg undcr prcssure at tclnpcrrlulcs up to 120"C.,

Whcn nranu[ac t re rs bcgaD produc ing coDoly , r rc rs -o f ac .u_ronr l l ie , . Urc pos i l ion c l )angcd. Thc rna in rcnson fo r in t roduc i r iul sccond conrponcnt into thc polyrrcr rvrrs to cstlblisir i i ;.;;; l l

;|"'::i,i",:'?l;"Jl]",lt,l::ill""s attcrtor poittrs ror trvcstrrrrcop.oryn,crs ;",,;;il;,, i;; ;;;,,1':1rl:llJ:T"t:'1,, ll,;'iill,l']ll'',",

' l ' l : c n to r ro l re rs usc( l to ( lay as secon( l co l t l )o lcn ts in acrv ,lon l rn te copotyn ters a re con) t lon ly o I th rcc gcncr l l c lass t ,s ,deper rc l i lg on the Lype o f s i t c they o l fc r to t l ycs tu i l s :

(l) I4onom-ers which providc non-ionizing polar groups wlrichare able to form co-ordination conrplcxeJ *it l, jy".f 'uffr, l 'g.vinyl acctate, mctlryl acrylate,(2 ) Mor romcrs con la in inc bas l

oI forming ionic bonds *iii., ""ili "fut ulr];t:')""ttttps c:tprblc

uu!'],"y"""11T"";i,";":Uiiji"" ;i"il,ii,Td': "f, j rl:jliTfi, t,]!l;.,

Jn addition to providing anchor points for dycstrrl l nrolcculcs,

ii:! 1:lfi f; ,,tif 'lffi.;ti: if:'i;:iilliliilr':;"l,li xl;ij:Ti:

l:.^r1:'j"d, and ttrc desrcc ot crysrrtiinity i. i.i*"i.,i. 'ir'rrr".

.p,"it rom. thasc copo lynrc rs n rc n rorc rcccp l i vc lo so lvcn ts , t rc ing n io rc

lllilll,,l;"t,"o and nrorc casiry pcncrrarcd by <tycsttirt ,,,,i otl"i

- - ] - l ]s l i t ter e f lect is not apparent , horvcvcr , in t l re casc ofsraf tcopolynters, as use( l in the product ion of the r r i t r i le af toy f iE ics.

403402

I I A N D I ] O O K O F 1 ' E X ' I ' I L E F I D R D S

The in t roduct iqn of the gra l l does not af fcct the for ln o l ' thcpolyacry loni t r i l { backbone, an( l the res is tance to so lvents i l r th iscase may actually be increased.

Today, acrylic fibres are procluced i[ wbich receptivity to alltypes of dyestulf has bceu built irr.

STI{UCTURE AND PROPEITTII]S

The propcrties oI polyacrylonil.rilceach manufacturer producing athe blend of properties tbat hcrcqurremcnts,

fibrcs vary ovcr a widc range,fibre or fibres that will havefeels will meet his particular

6s%i.h.2ooc

j 2 0

.-c

o

o -

20 30EXTENSION %

)\i9 (€r- \3

{o9*@lix'{-\ dl

9^@r"*o@8 86@

@"{

.^@@rN^ffiR@

'Coutlellc'

404

*-- t l r .1 ,r- I i . I . I r r I

r , : sYN.I . l t [ . ] - tc FI t rRus-f'hc

acrylic fibrcs o[cr unus.hi,rircrcrisrics or rhc 'brc ",", tl jf,gll Jl,llll'",1":l]::i;,,lli:(rcgrcc.by selcction oI a pirrticullr typc of acrylorritrilc ;;;;r,;i;;;,;1.contro l l ing lhc sp inning condi l i irrrc arrerria.ricrii i;;. ?;i;;;",:',,jffii, il"t;to,:,1j' :lii,:l"',::lll i iDc S(ructurc anrl Appcar;rncc

Acrylic fibrcs arc ploducccl in tr virrg u'on rr'";;,i;iri;;.;';,,;;;,'Ji::il",1,:'lii;::'""'i,:.:''.l:11'''l:;ger:cral, wc1 spun fibrcs havc a roun<l or t i,l,i"y_ i*-",,

' ,i,,, n".icross*ectiorr. Dry spun fibrcs rnay bc of dog-bonc ,r, ft,,t '. l lrrr-sect ion. Many b iconrponcrr t acrv l i i f ibrcs . , ; '1 , - , f , , . . , i , y i j . i i , i lI t igh-bulk f ibrcs on processing.

'

'fcD:tcily

'fhc eady typcs of..polyacrylonitri lc l ibrc, wlriclr consistctt oI l{X)

l)cf ccnt rcrylonitr-ilc polynru, rvcrc highly ori.,,rnLJ ,,uii ..,:u*i"i-4 . O

z

26.5

.-}

- 2 o

F

17 .5 r. onroru @ azz, zern l r@g. cnrsuru@ 5oa. acntLar@ ro

1 . O

lo

Slrcss-str i t in Ctrrvcstcslc(l t t

20 30 40 50 60 70 BOsTnatN (% ELoNcATtoN)

.for,.Sonrc Corrtrrrcrcit l Acryl ics. (Singlc l ibrcsstrrrrt lart l cr lr<l i t iorrs)-Cheustran,t Lt . '

405

s

t l n r E n E n n t E h h h h - h t l lI I A N D s O O K O F T E X T I L E F I B R E S

Iinc Iibres in rvhich the molecules rverc held togcthcr t ightly bythe intcnrolcculaI forces acting througlr thc uitri lc groups.

Thc introduction oI a secolrd coll]ponent into lhc polynlcr,rvith lhe primary object of increesiug dyeabil ity, rcduccd thcprckabil ity of thc long moleculcs and aflected thc mechauicalpropcrties of thc l ibre. The tcnacity of copolynrer acrylic f ibres,fo r example , i s lower than tha t o f the 100 per cent acry lon i t r i lefibres, other things being equal.

It soon bccamc apparent, however, that acrylic f ibrcs wercgoing to make their way in the texti le nrarket through attractivelrandle, resil ience, case-of-care and other properties, ralltcr thanby virtue of high tenacity. The recluction of tcnxcity whichfollorvecl introduction of a second componcnt inlo the polymer,thcrefore, was not oI serious conscquence. The tcnacity of acrylicfibres remains high enough for the type o[ applications in whicht hese fibres serve.

T1'pical lenacity ranges of nrodern lcrylic f ibrcs are as follows:

( l \ S ta l le a t rd TotvDry : 17 .7-31 .8 cN/ tex (2 .0*3 .6 g /den)\Vet : I4 . l -23 .9 cN/ tex ( I .6 -2 .7 g /den)Std . Loop: 15 .9-20 .3 cN/ tex (1 .8 -2 .3 g /den)Std . Knot : 15 .0-20 .3 cN/ tex (1 .7 -2 .3 g /den)I l .T. : 29.1-37 . l cN/tex (3.3-4.2 g/den), ary

25.6-3 1.8 cN/tex (2.9-3.6 g/den), wet.

(2) Filantent ( 'Creslau')Dty : 35 .3-36 .2 cN/ tex (4 .0 -4 .1 g /den)wet: 26.5-33.5 cN/tex (3.0-3.8 el(len). -,.-

Tensilc Strenglh

S tap le : 2 ,100 -3 ,150kg /cn r? (30 ,000 -45 ,0001b / i ' r 1 )Fi laruent : 3,500-5,250 kg/cm I (50,000-75,000 lb/ inr) .

I i lorrgation

Strp lc : 20-55 per ccnt .F i lanrcnt : 30-36 per cent .

[ l .sl ic l{ccoyery

Acryl ic l ibres have a bigh clast ic recovcry fronr snral l extcnsions,

a : s Y N l l l E . n c T I I I E S

l ,g - ; ?0 91 pcr cc r t i r t l_ pcr ccn t ex tc r rs io r r . , l . l t c

rccovcry t ron lurgher. extcnsions is.nrodcra{e, e,g. 50_60 pcr ccDt at l0 pcr ccntexrenston. ln general, tbc rccovery charactcristics ..r"nlb!" t l,or"of wool.

lui(ial l l{odulus

Acrylic f ibres have a high init ial nro<lulus, conrnronly in thcregion of 353-44.1 cN/tex (40_50 g/rlcn).

Averagc Stit lness

Strple f ibre: ( ,?- 99 "N/ lg" (7_ l0 g/ctcn;.l . t lamel | t : 14 l_362 cN/ tex ( l6_4 t g / ( l c l l ) .

Avcrrgc Tougllrcss

Staple: 0.40-0.70F i lament : 0 .2T0.49

Spccil ic Gtavity

l . t 6 - l .18

Dltcct of Moislurc

l{egain: 1.0-3.0 pcr cent.Water absorption at 20"C. and 95 per ccnl rh: 2.0_5.0 Dcr ccnt.

The water absorpr ion by acry t i cs i s rc la t i vc ly l " * , l i , r ia i .su l t rc rcn t . to rcducc the d i f [ c r r l t i cs assoc ia tcd w i th ( l cvc lonn)c l | tof static chargcs (e.g. by comparison wirh polycsrcr f ib.";j. i i i ;a rso a s rg t t rcan t l i l c lo r in lhc cornp l ra t i vc ly goot l dycab i t i t y o facrylic f ibres.

. Tbe tensile propertics of acrylic f ibres arc allcctcd lo sotnc

::gle-e by waler, rhc tcnacity, for examplc, bcing recluced to/)-y) per cent ol the dry tenacity,

Thcrmll I'ropcrlics

Acrylic f ibrcs do Dot havc lrLrc rlelt ing poi[ts, but lcnd to sticklo nrctal surfaccs t\t Z|5-Z5S"C, whcn prcssecl agliust thcm.

ElJect ol IIigh 7'en pcrat ure1hc mcchan icu l s t rcng t l l o f acry l i c l ib r .cs i s no t sc r ious ly i r lpa i rc t lby cxposurc to l le i l t . ' l ' hc

tcnac i ty i r f t c r I00 l rours i r t I55"C. i stypically about 96 pcr cent of thc original tcnacity.

406 40'I

I I A N D B O O K O l ' l - C X f l t , E F l l ] l t r r s i

After l5 nlinutes at l30oC., acrylic f ibre nray becotne cream-colouretl. As heating bcconrcs more sevcre, the fibre bccomcsprogrcssively rnore discolourcd. At 150"C. it is noticcably yellow ftcr I hour. At 250"C. the l ibre darkens through ycllow andbrown to black within 5 minutes and bccomes insoluble in therrsual solvcnts,

Whcn acrylic f ibres are hcated, thc mocltrlus falls and thcy arccasily strctched.

'Ihis strctching, iI carricd out carcfully, is a

revcrsible proccss caused by increased oricntation of the polynrcrnrolcculcs, without nny apprcciable plastic f low taking place. lIthe stretchcd fibrc is cooled before tension is rcleascd, the fibrercrnains in its stretched form. If the stretched and cooled l ibreis lrcated again, however, it wil l rclax and returl to its originall cng th .

This abil ity of acrylic I iblcs to assumc a tnctastablc state ttttcrbcirrg strctched at high tcnlpcrature is used iu tl le prodtrction oIhigh shrinkage libres.

Flonnnbil ity

Acrylic f ibrcs wil l burn, but thcy arc uot dangerously flantnrablcli brcs.

Eftcca of Sunlighi

Acrylic l ibres have cxcellent resistancc to thc ellccts of sunlight.Aftcr 600 hours cxposure, lhs tcnacity of a fibre is typically96 pcr ccnt of the original tenacity.

Chcmical Properlics

Acicls '/'

Acrylic l ibres arc unaflectcd by dilute solrtt ions of strong mincralacids, but they tcnd to bc attacked on prolonged itnmersion inconccntrated solutions.

Alkrl is

Ditutc solutions of caustic socla and all solutioris of sodiunrcarbona(c and bic:rtbontlc havc no cflcct on l ltc trtcclrtnicit lpropcrtics o[ acrylic f ibrcs. Stroug alkrl is attirck the [ibrc.

Acrylic 0brcs are rcsistant to nlost colnnton orgattic substances,

408

. F

R : S Y N T l l E r u C F l t t l 1 . I s

the , f ib re . s t rc r rg th bc i r rg lpprcc i rb ly u l ta l ' l cc tcd by cor rcc l t tn r tc t lc r rDoxy l tc . .ac ids , pheno ls , r l co l ro ls , kc to r rcs , hydrocarbor rs ,c l r lo r i l l a ted hydrocarbor rs o r ( l c tc rgents .

. Sornc. Jess conrnron organic substal)ccs suclr lts t l irrrctlryl

ro f lnamloc , d -bu ty ro lac tonc , d in rc thy lsu lphox idc i r d c lhy lc r rcc rbooatc are solvcnls for acrylic f ibrcs.

_Most salts are without cflcct, but vcry conccotratcd sollt ionsof sod iunr a rd ca lc iunr th iocy ln i r tc , z i i rc ch lo r . idc . , , . t . . i r i , ino(ber salts act as solvcnts.

Eltect of Organic Solvenls

Acrylic f ibres gencrally havc a goorl rcsisllncc lo comnlonorganic solvents, including those lornrally uscd .in tlry clcaning.Iosccts

Acrylic f ibres are not attf lckcd by moth l lrrvac or othcr itrscctti.Micro-orglnisms

Acrylic f ibres arc not alttcked by nricro-orgunisnrs. Flrbric buricrlIn . sor r . con la tn rng var ie ly o f n r ic ro_org : rn is r r rs rc t l incd i l songrna l burs t ing s t rcngth i l f t c r 6 rno t r ths . Co l ton , un( lc r s in r i l rconditio.ns, had undergonc a complctc loss of sircngth aflcr 2weeks' incubation.

Elcclric{l Propcrtics'fhe

clcctrical resistancc o[ acrylic f ibrcs is o[ thc santc ordcr lrsthat of other man-madc fibres.'fhe follorvirrg tablc, for cxrnrple,shows lhe electrical rcsistance o[ ,Courtcllc'

in colrp;,rison ruirt isome other fibrcs. Thc mctsurcntcnts wcre lakcn on scourctlsanrples, altcr conditioning at 50 per ccnt. r.h. and 20.C. For cachmeasurement 1.5 grams of thc sanrplc wcrc placc<l bctwccn twocircular electrodes, and thc.rcsistancc nrcasurcd oll thc l).1).L.Ivlcgohntcter at a tcst pressurc oI 500 volts rvhilc thc sarrrplc rvlrsrunder a load o[ 30 g./sq.cm.

Rcs i$ tu tcc (x l0 '1 o l t rns)Acctate -5.0Cotton 0.006'Courtclle'

5.0Nylon 6.6 3.0PET Polycster 5.0I{ayon sraple (,Fibro') 0.014

409

_ F--l -l r I r ' - l r I ' l ' t - I - ] | a l r l r - I r F t - F Hi

I I A N D B O O K O I : I E X I I L D I I I I ] I I E S

r\ l lcrgcuic I ' rottct( ics

Acryl ic l ibres appl icd {o t lrc hurrr l skin for long pcriods hrve

shorvn no dcrnratological o[ other i l l cl lccts. ' fhe

l ibrcs have no

known toxicological cffcc(s.

I lcfr lct ive lndcx

1.52 ('Courtellc').

r'.CITYLIC FIBI{ES IN USE

Gcncrrl Charactcristics

Cross-Sccliotr

Acrytic f ibres lre ntatle in a valicty of cross-sectional shapes, and

this has an inrportant cllcct on tltc naturc of the fabrics produced

from thenr. Wcl spinniug, in gcncral, yields fibrcs of round

or bean-shapetl cross'section. Dry spun fibres are generally of

tlog-bone or f lat cross-section.

Thc bcncling sti l lncss of a fl l ttcDed cross-section is less than that

of a rourrcl cross-scction {ibrc o[ equal cross-scctional areir; thc

CHARACTERISTICCROsS. SECTIONAL

SHAPE

a)ROUNI]

C'BEAN

c

L:f-jJ u

OOG IJONL D

(- ross.accl ionxl shnt- 'c , L i lcct on

I D E A L I Z E OSTIAPE

NATIOAB/co

STIFFNESS RELATIVE TOROUND FTBRE FOR

BENDING ALONC AB AXIS

c,.\

A ( - l - ) sv

o

c,.\

A { - . I - J - B 1 2 0 . 8 2vD

1

2 0 0.5?3 .O O .54

l lcrr i l i r)g Si i i l l rcss-Cltct, t t tratt l

4 1 0

A ; S Y N T F I E T I C F I D R E S

bcnrling sti{Incss of a 0atlcncd cross-scction with n lhrcc-to-oncratio of principal axes is approxinurtcly onc-thir(l th t of irround fibre of cquil l oricnlitt ion. Many clry-sPurr l iblcs lrirvcrbout r t ltrce-to-one ratio oI principal axcs.

IJending stiffncss is also dircctly rclrtcd to nrotlultrs, anrl itfollows, thercfore, that oricntation (which strongly nllcctsnrodulus). wil l havc a significant clTcct on bcnding sti l lncss.Changcs in oricntation may thus tend to nli lsk or rcitrforcc thccllects of cross-scction on bcnding sti{Incss, dcpcn<ling otr lhcway the two factorc arc combincd.

1'hc high bcnding sti lTncss o[ thc round or bcan-shrncd cross_scction acrylic f ibrcs is particularly advantagcous in carlrct f ibrcs,contributing to rcsil iencc or spring-brck. A fl l(tcnctl or'tJog-bonccross-section, on thc other hand, is conrltrcive to ft so[tncss oftouch in fabrics nradc lrom this typc of f ibrc. Thc dog_bonc typcof acrylic l ibre also has a dislinctivc cffcct otr thc rcncctio,i,rfl i gh t , rnd th is i s o l tcn no t iccab lc as a s l rcc r r o r l l s l rc in cc r t l infabric construclions.

lvle clnricul PK)pe icsT l rc .s t rcss-s t ra in rc l l t ionsh ips o f d i t l c rcn t acry l i c f ib rcs v i t rv ovcra wr(tc_range (scc pflgc 405), cach fibrc bcirrg tlrc pr"o(l ltct of itspur t i cu la r chcnr ic ; r l and p l tys ica l s l ruc tu rcs .

Thc dcgrec oI orientation r.csull ing fronr rlrawing is :r ntoslirnporlant faclor in dctcrrnirring thc- nrcchrnicrl 1riof",: i i ." 'oiulc lore. uls tnay bc sccn froll l lrc cliagrarrr on pagc 405,showing the stress-strain charactcristics o[ a spcctrunr;i i*yli;f ibre typcs. Continuous fiLrn)cnt, as excntplif icd try ,Ci"ri"ni :,is usually nrore highly oricnrc<1. .Orlon' zb, o,, tt,i "rli;;'ti",,;:has a vcry Iow degrce oI oricntation. Ali possiblc unri,iiio,i,betwcen, and cven beyond, lhcse lirrrits arc possiblc.

In gcncral, thc tcnacitics of acrylic fibrcjnr:ry bc rcgurdccl :rslying in a rangc bctrvccn llrirt o[ standar(l r"ivun .,i.1 i,uin,,.Acrylics arc strong cnorrgh for all lhc uoru,"l "pp"r"l "p1il;c,r-tions bu(. are not usually consi<lcrcrl for high_sticngrh airplicu-t ions such rs thosc in which ny lon and poiycsrcr . i ibr" r ' r " ru" .

Allied with good tcnacity arrd cxtcrrsion is an cxccllcnt cl;rstictccovery ancl high initial motlulLrs.'lhc nrcclrntrical l)rol)crtics ilsLtd.

4u

I I N D I ] O O K O F T E X T I L E F I B R E S

a whole, thercfore, arc sucl'r as to nltke for the production offabrics oI good dinrensional slabil ity. Most inrportant of all,perhaps, is thc fact that these nlcchanical propcrties are rctaincdirr conditions which rvould tend to bring about deterioratio[ innrany other Iibres. Acrylics are not significantly afccted, forexarrple, by cxposure to sunligllt, moisture, nricro-organisrns,chcmicals or solvcnts.

The rncchanical propcrties of acrylic f ibres combinc to providcthe attractive handle which is so irnportant a charactcristic offabrics coustructed from thcse l lb|cs,

S pccific G ravity

Acrylic f ibrcs have a low specific gravity, slightly higher thanthat of rrylon. Thcy providc l ightweight fabrics which bulk well.

L4 oislta'c

The rvalcr absorbcncy of acrylic f iblcs is geucrally low, but it ishighcr than that o[ polycstcr l ibrcs. Aclylics do not,:rs a rulc,prescnt the dimcultics caused by accunrulatiorr of static clectrjci l.yto thc c-\tent that polyestcr l ibrcs do. Also, thc snrall watcr absorp-tion contributcs significantly to thc dycabil ity of acrylic f ibres.

Watcr brings about only a ncgligible amount of swell ing oIacrylic f ibres, and it has l itt le ellect on nrechanical properties.-fhis

contributcs greatly to the climensional stabil ity, wrinklercsistancc and easc-of-carc chalactcristics o[ fabrics n1ade fronracrylic f ibres.

Despite the low moisturefortablc whcn worn next tothc reat.l iucss rvith rvhichwick ing .

7'hcrnral Propertics

Acrylic f ibrcs tcnd to be heaLscnsitivc, ancl heat-sctting isn€ccssary to achieve good stabil ity. I ' Ieatcd Lo higlr tenlpcratures,the fibres deconrposc rathcr than nrclt, but the tenrperatureat which this takcs place is sufl icicntly high to causc no practic ldiff icult ics in Dornral tcxti le applications.

In conrmoD with other thermoplastic l ibres, acrylics may bcheat-set. Fabrics made fionr 100 Der cent acrvlic f ibrc or fronr

absorption, acrylic fipres are conr-thc skin. ' l-his is due,Vcry largely tothcse fibrcs will rctnovc watcr by

4t2

' [ - [ ' [ i r - t r - r\ t

B : S Y N ' r I I E T I C F I I T R E S

}l:"']it.?l!)illj"r 50 pcr ccnr or rnorc rcrytic litrrc rrlry trcqr r raDly p tca led .Acrylic goods arc modcrltcly f lanrnrablc.

High Bulk Fibrcs

Thc. Iong polymcr molcculcs in a polyrcrylonitri lc f ibrc bchnvc.l:,,19::Sh thcy.are conrposcrl ot I nrixtuic of r""*onuifv -*"if-

orocrco crystallrnc arcas and lcss rvcll-orttclcd or lrntoinhoLrsarcas. Evcn fibrcs spun fronr ptrrc acrylonitrilc .to ,,oi ,t,o* iiosame dcgrec ol order.fls is possiblc in [ylon antl polycstcr ll l)rcs.r 'ur thcrmorc, ncry l ic f ibrcs do not dcvc lop n iuc i addi t ior r r lcrystallinity on orientation or hcat-sctring. i-trcy Aitfcr iir rti isrcspcct from polyamide and polycslcr li l ics, arri u"ryii"' i iri i.""lrc ln cot'tscquence more dill iculI lo heat_sct.

'Otlur ' I) iconp<tn<,nt I t i l r t?. 1.1\c crinrp iD this f ibr.c is nrr irrhcrcrrt

ill'jg!'i i"f ili|ii J;i:il"lli.Ji'::il';iliil lul*: jl,llnl liir;lil:l1l+*i1jirdl"iiii,,l, *",tl'il*l:1,,:i:lll,x,ji:lji;il,*i,i."' ";."T.' ii.:'ili:'Jll,:,illl lll?lH ll ;il:,il,1"'"ll"l:l,,lili_'ilf ".,lll:l

4t3 IIIr - I

r{t1

tlotsrun€ I|tt5PrRi! cniMp REtIxtsl l /D I l lE f l0REsrni tc I lS 0uT

Lrv{60

ls l l l l lurAclUnto, 'oRLoN'srcoHPoNEltI f tEnE l ls AHOD€RAT€ AI.IOUIIT OT R NOOHSPIRAL CNIM P

hrrTfl DnYlllc rutI cRtftPtNc0tvfl.ots. tT ts lt s cnfiP-n{G ltin0u6fi DnYtNc TI|AIls l( l {0t t As RtvERSt0Lt

['11 ft1 lt1 F. t Fi l"i t l''i l"i Fi l''l F. l"i Fl" t l''l l''l_ 11 FJ} I A N D B O O K O F

' T E X T I L E F I B I I E S

lVhcn antorlthous polynrcrs arc slretcllcd, thcy ttndergo sonlc

nro lcc r r la r o r ic r r l i l l i on . \ \ ' i l h i r rc rc l rs i t tg s t rc lc l l i l l l d l c t l lPcr i l l t l r c ,l lrc rnolcculcs begin to slidc past ooe anotlter, and plastic f lorv

lirLcs plrrce. If orictrt lt ion is allowecl to occur wilhout pl| lstic

florv, ancl lhe stlctchcd fibtcs arc coolcd, thcy wil l rcrnain.in thcir

slrctchcd fornl t l l l l i l such l inle as they are agaitt hcatcd to thc

point at which thc nrolcculcs are lrec to move The ftbrcs rvil l

{trcn retract lo thcir unstretchcd form.Acrylic f ibrcs bchave jn this tnanner when hcatc(l and slretchcd'

buL thcy also hrve a proPortion oI well-ordcrcd crystirl l inc

lcgions.'fhcse act as anchor poin(s for t lre molecules, prcventingplustic f lorv fronr taking placc and cnstl l ing that the molcculcs

icturn to thcir original positions rvhen the stretchcd fibrc is

hcu(cd antl allowed lo relax.1'his shrinkage rnenrory of acrylic f ibrcs rnay bc lost, o[ course,

iI cxccssivc plaslic f low trkcs pl;tcc by pcl'sistcn! strctching nt high

lcnrpcr r tu rc i , o r by annca l ing thc l ib rc r r t cons t n t l cng th . ' l ' hcsc

tccliniqLrcs are, in fact, usetl by l ibre prodttccrs to l.Dirke (ibrcs of

h igher tuodu lus .Prccisely controllcd, shrinkable fibrcs are macle by most acrylic

,ibre mirtrulacturcrs for usc cspccil l ly in swcaters and knit goods'

l-hc:c fibrcs havc built- in shrinkages of 20-23 per cctrt for

optinrunr bulking e{fccts, and arc rcferred to as rcgular slrriuli lge,h igh-bu lk o r h ibu lk acry l i c l ib rcs .

1-hcse high-bulh acrylic f ibres are used for crcrting l ightwciShlyirrns ancl fabrics rvhich are bulky irnd warm. High-bttlk yarns

lrc nradc, for cxamplc, by spinrl ing togcther slrclchcd xn(l

rcgular f ibrcs. Attcr t lre yarn has bccn spun, it is thcrlcd urdcr

.oi<'l i t ion. rvhich bring about rclaxatiotr of thc sllplchcd fibrc.-l 'his

shrinks to i ls prc-stretchcd length, forming a rcore'iu thcyrrn. The unsifetched fibrcs buckle and crinrp, and arc fotccd tothc outside of the yarn as lhe stretchcd fibtcs shrink.

Fabrics nradc flonr high-btrlk acrylic yarn are lofly anrl wartrr.ancl yct posscss lhc sttbil i ty to wcar and washing thitt js

chrracleristic of acrylic f ibres gcncrally.Acrylic f ibrcs of even higher controllable shrinkages are also

froducccl. Fibres of 30 to 45 pcr cent shlinliagc, for exatnplc, arctuscd in pilc fabrics, wherc they are conrbined with non-shrinking'hcavy-ricuicr 'gurrd hair' acrylic f ibrcs. The shrinkrge ltbrcsbcco | l l c lhc dcnsc , so f t inncr l t yc r o I s in ru la tcc l fu r , wh i lc thcgu:rrd hrir f ibrc gtrovidcs thc solt acslhctics attrl :tppcarrncc of

414 4t5

I l : 5 Y N l | | t i 1 t c t : l t r t t D s

natura l fur -

l leavy dcnier acry l ic f ibrcs caplb lc of s l r r ink ing I5 l )cr cc l tare uscd for spcc ia l s ty l i r rg ef fccts i r r carpcts, or lbr rc l r icv i r r respccia l ly . ( lensc p i lc for hc lvy rvcrr lpp l icat ior rs . Mct l iu l r s l r r i r r It l t ) rcs o l t l r is typc r rc a lso uscr l rv l tcrc lcss s l r r i r rk i r rg r r t l t l tc rc l i r rcless-bulk i r rg is desi rablc in both kn i t tc( l and ,vovei r appl ic i t iorx

Processirrg techli(lucs lrirve bccn dcvclopctl for r:n'kin,.: rrsc ,rIt l rc h igh-shr inkrgc charactcr is t ics o l : rcry l ic I i l r rcs, , l .hc7 to Zprocess devclopccl by the L incn Inc lust r ics l lcscarch Associ r t ionin Nor thcrn I re la ld is based on st rc tc l r i lg acry l ic tow or o l l lc rsynthetics to.approxirnately 20 pcr cent and thcn l'ectli|g tlrc torvthrough i rc lax ing zone wi th co ls tant t lkc-o l f ar rd v i i rv inu thcspeed of the input.'l 'he torv is tlren cut to strplc antl piocissc,lin t l le coDvent ional rvorster l rnanncr , cnal t l inr a rv l ro lc r l r r rc oII ibre shr inkages f ior r r 0 to 20 to.bc prothrccr l l l I rcr ;u i rc t l , h ighcrshr i r rk lgcs nray bc achicvcd by t l r is prcccss.. Acry l ic kn i t t i ls y i r f ls p loccssct l by lhc A Io Z (cc l ln lu t rc l lxvcl )cen .uscd successfu l ly i l t thc [ ie l t l o f ch i ldrcr r 's sc l rool ivcrr r . Al l lg l l . l )u lk- to .wcig l l t . ra t io lakcs l l t is ysrn vcry ccorXrr r r icu l l i r rn t l l ( l -Kn l tUI |g . an( l le ga f l | le ts a re r | lac l r i c -w l rs l tah lc .

Another proccss which rnakcs usc oI thc high_shr.inkugc:lpabll it l . of aclylic f ibrcs is lhc pcrbul proccss dcvclopcd iyN l i t s t rb ish i Rayon anc l Da ido Wors tcd Mi l l s o t Japur i . . fh isproccss dcvc lops t r l l c r r t l r t ing scgrncnts w i t l l shr iDk , no-shr i r rkpropcrtics within individual f ibrcs; it is dcsigncd for thc wooltcrrsystenl.

ItLvit oturre tal Conlitiort-sAcrylic f ibres have outstanding rcsistarrcc to sunlight, nticro_organisms, insects and agci[g, and havc cxccllcrrt outdoorwcathering rcsistance.

Chenia ,l lcsistttnce

Acry l i c f ib rcs h lvc a good rcs is tancc to a l l t l r c chcr r r i c r r l s l i l c l vto bc cncout ) l c rcd in r ro r r rn l t cx l i l c usc , i r rc lud i r rg b lcachc i .dilutc acids and alkalis, dry-clcaniug solvcnts, ctc.

l t r . r D s o o K o l : r 8 x 1 I L l l l : l l l l l L s

Iilcct ricol P ro perties'l 'hc

lorv nroisturc absorption lcnds 1o cocourage accunrulirt ion o[sla(ic electricity, but this nray bc ovcrconrc by the use of suitableantistatic f irrishes.

Hclical CritnpFibrcs with a hclical crinrp develop morc bulk than fibres rvitha planar, zigzag crinrp. Also thc hclically-shape<l l ibrc has rnorcrcsil iencc lhln a sirnilar I ibrc o[ z-igzag lorm. Such fibres resisl.matting and inter-fibre slippage belter than fibres with planarc r imp.

Crirnped nalural f ibres, l ike wool, teud to have a helical crimp,rvhcrcas rnan-nrade fibres comrnonly have a planal, zigzag crinrprcsulting from a gear or stull ing-box proccss opcrated with thehclp of hcat and prcssure.

lvlcchanically-induced crimp tends to be pullcd out ra(hcrreadily from acrylic f ibres during norrnal texti lc proccssiug.'f lr iscan be prevented to some cxlenl by lreat settiDg.

l{elical crinrp lnay bc introduccd into aclylic l ibres bymechanical mears, e.g. by a falsc tlvisting and sintultancous hcatsctting operation l ike that uscd ior nylon and polyester f ibres.It nray also be introduced by spinning the fibre in bicomponentIortn.

In 1959, du Pont introduced their 'Orlou'Type 2l f ibre, whichsubsequeutly bccanrc known as'Sayelle'. This fibre cornbines twofilatrtcnts in a single strand, lhc fi larnents beirrg luscd lengthwiscto form an acorn-shaped cross-scction. A dil lcrence in shrinkagccharactcrislics produccs a permanent and revcrsible crimp, pro-viding a fibrc with exccllcnt covcr and compfessional rcsil icncc,inrprovcd bulk and lo[], good wrinklc rcsislautc und case-of-carcproperlies. Helically crirnped fibres rvere also devcloped iu whiclrt lre hclical crimp was unaffected by moisturo

This typc of bicomponcnt acrylic staplc has proved particularlyuscful as a l iberli l l for pil lorvs, quilt ing and the l ike. Thc l ibrcslend to rcsist Inatting by rcruainiug inlcrlocked, even throughwash ing and dry ing .

IJclically crinrpcd acrylic continuous fi l :rmcnt yarns wcrc sub-sequently inlroduced lor srvcltcrs and knit goods, thc crinrp beingfully dcvelopcd after boil ing ofT. Coods made from thcse yarnshrve a crisp, wool-l ike haudlc and cxccllcnt clasLicity andd inrcns iona l s tab i l i t y .

* ' l r l

4 1 6

' t ' t ' t

o : S I , N T E - l t c r : I t ! R I s

Co inuotts I;ilaucnt ),anrs'l 'hc

orig-inal uscs [or acrylic f ibrcs rvcrc prinrrrri ly in irrdustl iuland outdoor applicalions. 'fhis

rv:rs largcly bccuLrsc of lhc porxlsolvcot and chcnrical rcsistancc ancl thc outcloor agcing p,.rp"if i.r.lt_soon bccalne apprrcnt thrt voltrnrc woulcl UJf l,,, i", l iu if,"rclatively high-priccd conlinuous fi lamcnt fi brc. f:"rfy i""t iui,r, i",for confcrring dycabil ity an<l lcvcl dycing in "onri,u,'u,i, r i i ,, i , i .,"iwcrc not sull icicntly succcssful to bc ccottotuically rrttr cl ivc,however, and most of thc devclopnrcnt o[ acrylic t itr", c"nir., itupon staplc fibre.

. Despitc tl l is concentrat ion on staplc fibrc,I l.crv firrrrs pcrscvcrcrlw i th cont i r )uous I i la r r rcn t acry l i c f ib re .a lx l bcgur r p ru , f u i iug- y . , i , .

Fabr ics r r ra t l c f ronr co l r t inuor rs i lanrcn trtcrylic f ibrcs havc a dry, silkJikc lr:rrrd, n,,,f ,,r" .,,,uoii i - iu,, i

rus l rous tn i r lpc i r tancc F lcccc and lcx t r t rcd kn i l f r rb r ics l r l c|l ir l.urally dry and soft to thc (ouch.

Producer Colourccl Fibrc'[ho.

dispcrsion of pigntcnts in the spinning solution providcsproducer colourcd or spLrn-dycd yarns, Altcru:tl ivcly, it is ltossiblcto uso slrbstantivc dycs to colour tlrc l ibrc rvhilc it is in thcswollcn statc aftcr coagulation arrcl solvcrrt rcrnovlrl.

Pignents or dycs arc sclcclcd wilh cxccllcnt laslrrcss propcrlicsrnd this type of f ibrc is idcal for ouldoor uscs, srrch as tirrpirulins,awDiogs and tents.

A_number of produccr colourcd acrylic f ibrcs l lrvc rppcarcdon thc market in rccent years.

Ir[oclifictl Surlaces'['ho

surface charactcristics of acrylic [ibrcs nray trc changctl to

4 t'l

t . n . . - - - - - - - - - - . - - - . - |l I A N D B O O K O F 1 f , . X ' � r I L E l : l s l r I I S

allccl important properties such as surface friction, antistaticLrchaviour and wcltability.

li ibres rvhich cornbine dog-bone cross-scctiorr, low crinp andlorver surface friction provide a smooth hand and lustrous appear-ancc to fabrics. Fibres of flat cross-sectiott tntl lorve r{han-norna Ior icnt r t ion resul t in a fa i r ly so l t hancl , yc l suc l l f ibres arc su l ' [ ic i -cntly rcsilient and stiff to form loops for fablic surface effecl.

Acrylic fibres with a durable antistatic surface ltave bcenclcvelopetl cspecially for blankcts. These fibres do not build upstalic charges as readily as unmodified acrylic fibres, ancl clissipatestatic electricity quickly. The antistatic property is permanent, atIerst through ten wrshings in a home laundry.

Silicone-trea t ed acrylic fibres are procluced for the U.S. Navy.These fibres are made into jackets which are water-repellent andllave excellent life-saving flotation properties. The jackets havehigh thenlal insulation valuc ancl offcr protection also againstshotgun b lasts , f ragnrentat ion ar t t l cvct t bu l lc ts .

A4odilied Ileavy I)atier tor Carpels

Special types of heavy denier acrylic l ibre are produced foruse in carpets.

\I

lYashing

l in i l t c t l and l igh twc igh l . garn lc t r ts o f I00 per ccu t ac ly l i c f ib reshould bc washcd i[ warm watcr (40'C., 104"F.) using a detergcntor soapflirkcs, whilc morc tobust glrorctrts such ls slritts lnay bcrvashed in hand-hot water (48'C., l l8"F.). Thorough rinsing inlukewarm watcr, followed by cold watcr, is reconrmended toprcscrvc the soltncss for which acrylic ftbrc fabrics arc outstand-ing. The usc o[ a proprietary softcr]ing agcnt in the l inal rinscrvil l also hclp lo rctain softncss ancl colour.

4 1 8 4 1 9

t r : SYNTH DTrC I I I A RES

. P lc t tcd garn tcn ts shor r lc l bc was l rcd by l ra r rc l anr l g ivc r r a war r t rrinse fotlowcd by a hand_hor (48"C., I ld"tr.) ' ; ir;;;;;;;;- j;:: i :Acrylic swc tcrs arrcl l i thLlv

r"rourv *,rsr.,J'i,; l'':,;;. "i;:i.j,,^t^"]s.l ruclcd 8^rnc. rs .r'c prc-

rvhicrr arc labeled as ruir"rrr" ro.'liln"iJo,li,,""il:"u tt s.rnrct)ts

Dryirrg

Acry l i c l ib rcs absorb vcrv l i t t l c ,

:::lil *i -'i' ; :J;' i' ;;l ;' :il' ;:' l$ lilr' :::;.il,:' l1;, i::'liIliIJ ili i"ii iliJ'il;il.:IJ,iii,[x!:,';:txt;'::*r *".:*:lvcry c tu ick ly , a l though s l ight ty r rorc ' i io l i ng, , r , ;y- i r ;

- , ; ; " ; , ; ; . "

ncry l ic g i t l )cnts rcqui rc l l tc rn,,'. r"r i il ;;;;;;,,;' l; l; "#;; llili):'j' ;ili "Jli,';:i:"1'il'.1il ;cxcecded, and rhar rhc nrachinc is ""r p"lt"j il,j'li*i,irr",,jiliiga nDcnts.

, The

.nrajority of woven and {irnrly knittccl glrrncrrts ntav trcd_rip-dricd, bur trcavy krrits should t " .riifJl"i :ii"l,iirr"r 'iiirrrlils not lecontmcndcd unlcss thc tcnrpcraturc ",,n bc "ontroli",ilo keep below 60.C. (I40"F.) followcrt by colct rurnblirrf.

"" """' '

Ironing

Kn i l t cd garn lcn ts a rc usr ra l l y rcady to wc i t r i l s sooD i rs t l rcv havcoflco. Sonlc garmcnts and wovcn goods nrly rcqtrirc a nriri inrrrnrof ironing, which shout<l be carricd out wirir a J"of iro" irili--CSetling l) on thc rcversc sicte ot the fubric wtr"ii iir;'g;;;iis dry.

Dry Clcnoiug

H*[:*i H:'fl t"fi:"l BJ fi ':iJ:l::,'iliil,J,iT;l,i:',fl1i

T I A N D A O O K O F T E X T I L E F I B R E S

The tumbling lcn'rpcraturc trrust rot cxcecd 60'C., (140'F.). Atrypressirg treatnrent given should be lighl to avoid glazing.

End Uscs

Chcap Raw Material'l 'here were a number o[ reasons for the rapid incrcase in thcprocluction of polyacrylonitrile fibrcs. Acrylonitrilc, thc basicraw maLerial, rvas available in plentiful supply attd at a vcrylow price comparcd with raw materials for other synthctic fibrcs.Also, the production of polyacrylonitrile fibres is rclatively sintple,and the patent position makes it possible for a producer tomanipulate thc basic principlcs and slil l evolve a polyacrylonitrile

. hbrc with traditional characteristics of this typo of fibre.Despite the astonishing progress oI polyacrylouitrile fibres, and

their rcady acceptance into a wide range of applications, the earlyyears were besct with many troubles. Fligh fibrc pricc and scriousdyeing problenrs held up progress during the early years.

At first, djspcrse dycstulls wcrc virtu lly thc only class thatcould be used on polyacrylonitrilc fibrcs. 'fhcsc dyes gavc s:rtis-factory Iastness in palc shadcs, and they are stil l used mainlyfor this purpose. But they do not build up to mcdium and deepshades, and lor the production of heavy shades, acid dyesl"uffsrvere applied, using the 'cuprous ion' technique. Tbis was not

r adoptcd widely, horvever, owing to difnculties in obtaining level' dyeings and thc restricted range of acid dyestu{Is having good

dyeing properlies by tl)e cuprous ion tcchnique.The brsic (cationic) dyestulls were found to bs complcmentrry

to tbe disperse dyestufls in that they would profide deep shadesof vcry good fastness to washing, and moderate /fastness to light.Thcy were nol cltirely salisfactory for plle shadcs, howevcr,bccause of a very high initial rate of dyeing. The mein defcclof the old type basic dycs on polyacrylonitrile fibres was thcirnodcrate fastncss to light. The ncwer types of cationic dyes havca very high fastness to light and irnproved dyeing properties.

Inrprovemcnt in the dyestulls and dyeing techniqucs has beenacconrpanied by the development of polyacrylonitrilc fibres withnrodi[icd propcrtics. The incorporation of sntall amounts ofsecond componcnt mononrcrs has provided acrylonitrilc copoly-mers rvith incrcascd amnity for anionic dyestufs applied byconventional dyeing methods. These acid dyeable fibres have

420

-1 1'-L--L-L-L-L--L - t :-t --t

421

B : S Y N T I I E ' I ' I C F I I } I I I ] S

founrl rc:rcly acccptancc tor blcnding rvitlr bnsic dyc:rblc fibrcslo produce cr.oss-dycablc fabrics.

Kni cd O utenyearAs thc dyeing 1>roblcnrs wcrcg rad ua I y,

' porjal;yr;;i,;ir.

";;;. -t"."-':otnc., rt tttl .lriccs tctlttcctl

lt*il,i:,*itrffr*ilrur"r"".':.lidi'ilfiii"l'T*lillrri',i"Tif

"r*l1; jti{itixil.l:{1""11i"lillii{'illtiliif*h","0, *ooi-.i""i*.' r,"i"ii dJl;:"uT::n:1i,,;illii,Ji''.]l[t:

iilit,,:'j:r,';,',..l:iitil?fift{i:ltff ,lii:::,,.,,115tii!ft l;y::l't' fr'','l".,ljl x1## .;* llllliil:i i ; "ii :'�:Tf L ilIli l'[:lf f; l;,1fi if ::i*i*#tnfi :,ii,1#l"i?,'"1;i",',f, t!i., jirvcre.supenor in clcar*biliry,"u'ji:1ff#luo,i,',i:lt rcsistrrcr', nrrtl

ur lgn lcr , c leaner shrdcs could bc obla incd wi th .Acr i l l r r r . , ar rdyarn yicld factors of 95-9g pcr c

lit**'*i'll-ir.l**;i[i[-$*i:tit,i5iltlurl'ffi fr [['',i{*;nd*[ii;ll;i::{"'.'J::"1"-"io::'"i:,l'lH"ll,^u"lrlxllil.,'J::n*,illli,p.rncticcs with poly_acrylonirrilc car.pct sriplc,-. nrl "ir ri"i,"lfii",' 'i#::.

"t. tons slapte worsrc<t spinning is'r,sc.r ir, y,i;;;;,,;;,,,',f*l

I t A N D T I O O K O I : T t l X ' I I L E l ' I B R E S

Funrishing Fabrics

Acrylic l ibres bave madc substantial progrcss in thc field of

Iurnishing fabrics, providing nralerials that combine luxuriottsappearancc with l irst-rate practical perfornlancc. Curiains are

mads in a wide variety of wcaves, ranging frotn sheer fabrics thrrt

have cnough body to hang wcll as pcrfeci sulnnler curtains' to

heavy velvets thrt provide richness ancl vrarmth all ied with easy-

clean properties that are a featurc of acrylic l ibres.These sanre characteristics of acrylic f ibres scrve them wcll

in blankcts and bcdspreads, ttpholstcry fabrics, tnblcclotlrs and

othcr furnishing and houschold applications.

Apparel Fabrics

Following the success[ul introductiorl of acrylic l lbles inlo lhc

knilrvear and carpct trades, thc acrylic n'la[ufacturers explorcd

othcr tnarkcts lor this type of f ib[c They had a fibre with ntanypropeltics sirnilar to thosc o[ wool, Lrttt with charactcrislics which

made it pre[erablc to rvool in n]any instauces. Rcsistance tonricro-organisms and insects, dimensional stabil ity lo washing,exccllcnt resistance to ouLdoor exposure, surlight resistancc' bulkwithout wcight, gooci covering power and a steady ptice are

sone of thc attractive fcatures offcred by acrylic f ibres whichpronrpted manufacturers to usc the l ibre in blankets, blends withviscosc for nen's and boys' slacks, blends with wool for ladies'

dresses and skirts, siugle jersey fabrics for rneu's aud boys'shirts,ladies'blouscs and dresses, and blends with wool for metr's slacksand su i ts .

ISinglc lcrsey Fabrics )Singlc jersey fabric made from a blend of rcgular and high-bulkstaple spun on the cotton system to 2ls count was an imnrcdiatcsuccess. The piece-dyed fabric is machine washable and very

stable. Acrylic jersey sports slrirts are now established iu a l icld

that was previously dorninated by cotton.

Tulred Pile Liners

In tuitcd pile l incrs, tho ttsc of acid dyeablc and basic dyeablcacrylic f ibres in combinations or blends has cnablcd pattcrned

liners to bc madc, 'fhis has bccomc fln important outlct for

acrylic f ibrcs.

422

n n n n n t n n t n r t t E F, l_lB : S Y N T } I E T I C F I B R B S

Cirarlar Sliver Knit FabricsAcrylics have bccomc cstablished in lhe Wildnratr circular slivcrl(nitt iog tradc. Liner fabr.ics and ccrtain typcs of oL,tcrwcrr fabiicssinrulating natural anirn:rl fur fabrics wcrc first prod;;"j"i;;;slock-dycd fibre and lalcr with solution-clyccl or.ri,"i-,fu",f n'fr-.In this cnd_ usc, the acrylics oficrcd arJvantrgcr' ifr^i ' .""f i-,_ioc mttcl)ed by othcr f ibrcs, cnabling rna n u fi lct rlrcrs lo rnflkcreasona_b_ly. priced, high qurliry fabricifor rt," ,"., ,n.it "i.

'-

,,,],", "oo,t,?n to thc-.l incr and outcrwcilr fabrics procluccd usinrrv l ton ] i ln c t rcU lar s l l vc r kn i l t ing nr lch i cs , no thcr i I | t c rcs t in I

use jras devctopcd in thc mcdical f icld. -I.csts conductcr.l i ihospitals wirh. acry l ic Debicurc pacls madc frr^,- ; l i ;;;;,; i i

rau. cs provcd U)at thcse corrld bc a rcnrc(ly for bctlricldcnpatients sullering fronr becl sorcs. Moreovcr, f^f]r1". "i i lr i ,1"""do not support bactcria, ancl can be clcanctl cariLy, ari. j 'q"i. ' t ivaucl prrt back into scrvicc,

Outdoor lrqbricsAcrylic f ibres havc cxccllcnt rcsislancc to suntight, iDsccts lndnrrcro-organisms, and acrylic fabrics havc "t*"vi 'fo,,n,t , i i",,.tuouucL In ou ldoor t lpp l i ca t ions . Wi th thc advcnt o f so l r r t ion-dyc t !or spu n -d-ycd. a crylics. ncw opportunlrrcs wcrc crcalcd in ltr is f icl(1./ iwurng tabncs n)oved in lo thc acry l i c pa in lcd co t ton and v inv l -corted cotlon arcas lnd ma<lc good hca<twry againsi "ri"frf ir i, l .fcotton fabrics-

. Pil lnrcnts with cxccllcnl fastness propcrtics arc available forthis..typc of. usc, caprblc of withstaridinb lhousrnrls "i l ," i"r '" isrnlighl wirhorrt rroliccrblc clrangc of , lo.l". l ], i ., ";,r; l"J i; i ;,1n" , .C99t ' t labr ic s l rcng th rc tcn t ion o f rc ry l i cs a [ tc r l rours o Isunr|gnt and weathcr cxposurc, has nradc ollrcr ouldo(,r uscssuch as flags,- ski-j i lckcts, hunting j irckcts, fr""t ."".r. ",Jswrolmtng pool covers natrrral oullcts for the fibrc

Floc*ing

Thc process of f locking has bcconrc an importtDt tcxli lc nltnu-ll:,!l,l]q ,pr?:... in rcccnr.ycars. This trns bccn <tuc parrly roInc rn l roduc t lon o f syn t l )c t i c f ib rcs gcncra l l y , rnc l a lsb to - thccorrsiderablc-advarltagcs oftcrcd by thc rcrylics nna nvfonr-ou.iU1c nil- lr lrat I lbrcs. ncrylics c:rn bc shippctl in tow forrrr whiclr isr ( rc i r l to r cu l l i | l g i r ) to f lock . ' fhc ava i l : rb i l i t y o f v i l r ioUs typcs o I

4 ? 3

I I N D A O O K O F T C X T I L E F I B R E S

acrylic in low counts, its luxurious hand and good recovery frontcrushing nrake it adnrirable for apparcl flocking use.

Acrylic flocked [abrics are now established in various ntarkets.Pilc flocked furlike fabrics may be matle from acrylic fibre,for exanrp le, and then pr in tcd, brushcd and l in ishct l . Otherapplications include velvet and corduroy apparel fabrics, sucde,toy aninral furs, souvcnir pcnnants, wall panels, paint rollcrs andrccorcl player turn-tables,

Flocked floor coverings are now being produced fronr acrylicfibre, aud acccptance has becn good in many applications. 'fhc

nrotor car industry, for exanrple, is using flocked floor coveringsin appreciab!c amounts,

TultingFine gaugc lufting has assumed a position of some inrportanccin thc tufting trade, espccially in tbc blanket scction o[ lhcindustry. Tulted blaukets and liners havc added to existing avail-able products and exlenclcd consumcr choicc in this field.

lly using various combinations ol'bright and dull fibre a witlerange of appearances and texturcs may be obta ined, and bypolishing and tigering such fabric a variety of cloths has bcenproduced for a range of markets.

Nott-wovctt FabricsIn the non-woven fabrics trade, the Clrrthanr Fibrc$pvcn proccssfor producing needle-punchcd blankets was the firAt sigoincanttcchnical development. in which acrylics playcd an important rolc.

l 'he l.ibrewoven process is r sophisticated improvement overordinary neeclle-puuching techniqucs. The usual needle loorrrenrploys necdles operating reciprocally in a vertical positionnormal to thc plrne of the wcb. Thc Fibrewoven nracbine employsnccdlcs operating at an angular displacement with respect to theline of travel of the web. By suitable dcsign of ncedle penetrationancl wcb advancc, a nrechanical intcrlocking of frbrcs in thcnr:rchinc <lircctiou is clfcctcd, rcsulling in improvcd fabricpropcrtics.

- T - l . T . lI

.t2,1425

' t r l

A : S Y N T I I E T I C T I N N E S

ffiffi*t,ffifiqtr,1',;;;"*'ffi ,,t",'#1ltl;d;jl,T*;$f itfi:ft'i,:jd:;xi{,'#:"*kiffi-fi*rr.;ffi'nrffrfir**NmfiffiCertain typcs of acrylic fibrc np pcrs. a re, cxpensi u", r,u t ioi ;#^ii"l.ll,il,ll li",i."i,li; r.:,.;'i

;""'i:"-l:l"lll,i':;";,,$::'"" pnp"" o" uic'r' to' *iii"i'r",' i"

XiT:il':il,1-1Ti""1,1,J',lllili'l"l'nc tvp.c. r,rvc r,rougrrr rcvoru-:, tu:;1:,uil..*sru;iil:lllt;;Ti,ilrurnltii:'J::Jli::1fl i.";i$,f :ili',;lii f,t,'.iu'r.,i,ii'" r,'i iiili"Ll",;lJ';i;::"Jii il,;i,l,'fi,'i;t?*:,,n:l*:::i il,lil.: Tl;;

:t l

other fibres are being used as the sheath fibres around the

"l,ttto*"ti" core. This typc of yarn is being used in cuffs' neck

bands and waist bands of sweaters, and in some iustances

,tt io"gfr"ut [he sweater, providirrg cornfort, good shape r€tentio,n

and itnoroved elastic propertics. Bathing suits' socl(s and douDle

jersey iabrics are .applications in which acrylic / elastomcr corc-

spun yarns are gaining popularity.

In the wcaving industry, core-spun yarns are.assumlng-.an

incr"asing impoitance, with stretch woven {abrics l inding

inrmccliaic tttoik"ts in ladies' slacks, mcn's tlousers and suits'

shirt ings.and upholstery fabrics. Elastomeric core-spun yarns are

being irocluced on cotton, woollen and worsted spin!l ing systenrs'

p.oui,t ing another outlet for acrylic f ibres in thc years ahead'

(2) MODACRYLIC FIBRES

This catcgory of polyacrylonitri lc f ibrcs includcs modacrylic

l. ibrcs spun fiom polymers consisling of lcss than 85 per cent-by

weicht o[ rcrvlonitri le units (-{l{1- cH(cNF). btrt excludrng

tlroic copolymers in which acrylonitri le is not the malol

comPonelrt.

IYPII jllglg

Thc nbres in this category are sptttr from an extensi'r 'c rangc

oI coDolvnrcrs of ncrylonilri le, in which the nature and propor-

rion of ihc sc:ond (rnd possibly othcr) componcnts Inay vary

within wide l inrits. The types of modacrylic f ibre that- can bc

oioJu."o wit}l in this broad cateSory are caprblc \of wide varia-

i ion.-in prop"tti"t, clepcn<ling on their compositio\ and method

of lr lanu[acttlre.--As in the case of acrylic f ibres, details of the chemical structure

of individual motlacrylic f ibres are not always avallable' l l lc

.""on,l "on',pon"nt of ihe polyrncr is, however, commonly chosen

frorn vinyl ihloridc, vinylidcnc chloride or vinylidcne drcyanr(lc'' - i i" iniorrnoiion whicir follows is based on data for vEREL*

fib;;, ;; l ; i t may be rcgarded as a rcpresentative l ibrc of this

tvDe.

trxdc |rlark of Eastman Kodak Conlpa[y, Itochestcr,* l{egistcredN.Y., U.S.A.

426

h h E f: h F, f': n E_ n n R F- n [ IFL f':-l'':-li ' r l r ! r ' l l

IH N D B O O K O F T E X T I L E F I B R E S I B : S Y N T I ] D T I C F I B R E S

VEREL

VEREL f ibre is o l the polyacry loni t r i lc typc; i r is prot luccr l bvTenrtessee Erstnran Conrpany, U.S.A. lt it riri ',, ' i ioii,

'o'":, poly-,, i. ',

or un( lsc losed cornposi t ion, in rvh ic l r acry loni t r i lc is prob:rb ly t l rcn)ajor conlponcnt, beirrg present to the extcnt ol'sorni 60 pcricnt.

By F.T.C. definition, VEREL is a modacrylic fibrc.

TYPES OF FII}ITE

VEREL libfe is manufactured olly in staplc form. A rangc oIstaple lcngths is available to suit all plocessiug systcnrs, in tbcfollowing deniers : 3, 5, 8, 12, 16,2.4 aln<! 40. Tha fibic is procluccdin bright or dull lustre, and various crinrp lcvels and diffcrcntdegrecs of crimp permanencc ars availablc.

Vll l lEL tibre is protluccrl in trvo l:asic cross-scctions, pcanular t r l r ibbon.

PITODUCTION

Mononter SyEthcsis

Acrylonitr i le. Sec page 399.

I 'olymcrizal ion

No iuformation avai lable.

Spirrning-fhe

polynrcr is dissolvcd in solvcnt (probably acctonc) nnd thcspinning solution is pumpcd through a spinncrct..fhc Iinc jcts ofsolution_ emerge probably dnto a coagulaliol bath (wct spirining),in which thc solvent is removcd to lcavc solid li lanrcnt-s. .l.hc-scare gathcrcd into a bundle or tow which is proccsscd to slnbili?.cit. Lubricating oils are addcd to aid i|l thc subscqucnt spinning ofyarns, and a crimp is addcd.

I I A N D I } O O K O F ' T E X T I L E F I I } R E S

The tow n]ovcs to x cutting machinc where thc continuousstrands arc cut into staple nbrc.

Pl{ocEsslNc

Scourirtg

Scouring of fabrics of VEREL iibre follows the general patternestablished lor other rnan-rrtacle fibres. A ncutral scouring with(letcrgent rvill renrove dirt acquircd front previous processing.

Alkalinc scouring should be carried out when necessary rvithr rn i ld a lka l i such as d isodiunr phosphate or te t raso( l ium pyro-p l rospl rate at 600C. A st ronger a lka l inc scour wi l l d iscolourV ER[,L.

l l lexching

VEREL iibre does not as a rule require bleaching, fls il is whitcenough for most enrl-uses. Soclium chlorite ancl lormic acid nraybe used to slightly bleach V[,llEL if neccssary.'l 'he use of opticalbrighteners plus small anrounts ofcationic (lyc is the most practisaland effective way to brighten VEREL.Dyeing

6) 100 per cett VEREL Fibre

VEREL dyes read i l y and no spec ia lequ ipne n t j s needed. In dye ingnrost shades a rlyeing assistant is used to ensure conrpleteexhaustion of the dye and to provide bcst fastness properties.

VEREL crn L :e dyed as raw s tock . ske in o r p iece soods a t anopcra t ing tenrpera tu ie o f? loC fo r be i t resu l ts .

' \

"

Thrcc classes of clycs ntay be used successtull 'y in dycingVEREL: (l) besic, (2) disperse, and (3) neutral prcrnetall izcd.Bosic D),es

Basic or cationic dye conrbinations arc available with cxccllentfastness properties on VEREL fibrc. When uscd ilr combinationwith thc proper dyeing assistants, basic dyes level wcll and exhaustelnrost corlrplctcly. In addil. ion, r cotltplelc rangc of shades canbc ob la incd w i th t l l csc dycs .

Propcr scleclion of dycs is jnlportant. lvlany basic dyes havcpoor fastness propcfties and certain basic blues are sensitivc tohext; they tcnd to discolour or rcduce iI exposed to high tempcra-

428

r II

429

a : s YNT I I [ . 1 . ] c F l t t . I i s

:'ifi,iT 1""':":i,i::1' or tinrc 'rhc usc or rlresc <lvcs shourd

- iriji * :tft s: ffi f JT,:x:| i,",# ;:: ll,Jli,,l,Jul ",,, ",*;i:!!!"t#J":,:,i' fi ifi h",.f riiJl';iili,i*i,i:,:"i,';fJ:ll'":ilii:'f,ji,lfi lli:",liiil1; I |.i# "","J,1,,',1';T ;''ii',lJi,,l,",:::l,l;""r""t",:";.""1::j5ll,lnillffi I ""#l:i jn Jl t"Xu:e".fu r'r{ii,,,,,;i!if tuii:iiHilq*llllliu,,illr,ll;u rr3)i,l.r: of re^perarurc ,ir. ( I'J3'/',t'!i,,;t']

bc obtairrctl bv usirr!

#.,yf*ifi '[T ;11;:]::"',,li"'""""'l,i flii:.Il'llii i"ll u :;:i"',, i IDisperse Dycs

;:iTl;',i:ff '1""?""'.llJ;.',"",*ifi i:**il;.iiil j*iiiil"'l"i,l;,3ii"'ii;'"x1 "';i:",*", -,:'Jl:","i'"J;ii',r,llilT*t;i#illx1:l,1i:ih:*iiir,!,::'_",.,,T"1;Neutrc Prentctdlized DyesTheso dycs have bccn uscd vcrv s

;t*fr * j.::li"i jf ::,Jf ,lthitt;ii:Tffi :xl,ti,'t;,il'"":tiY:,*l. VEIIEL Dyci g Assistan I

ii:d*d*ihi.ffi,:ffiii*qHr',.i"T'T1",,#?*;,1,'"',. iii'',,i1.fffi'JliiliJ'L ?,l.iil,,,i il;

tf f f f F_ F. f1 11 l"l l''l 11 l''i l''l l''i F'l l"'i t ll I'l t II T N D A O O K O F T E X ' T I L E F I B I T E S

2. Low TenPerature DYe IS

Al though Iuoclacry l ic [ ibres can be dyed at lemperatures above

i8;C. E-;'i;;i;;i l;;s'tlcvelope<l a rnetltocl ot dveiris vEREL. nbreat l i6C t t ra t prevents pacied dyet l cakes, yarn and fabr ic d is tor-

t ion, and sevl re delust r ing. Shades wi th Sood penetrat ion^and

lastness can a lso be obta ine( l a t temperatures as low a.s bu-L '

Low ternpcrature dyeing, however , requi rcs a good balance o l

dvei r re as i is tar t ts ar td carefu l se lect ion of dyes- Al i tvpes of VEREL f ibre can genera l ly bc dyed at low

tenroera iures. but basic dye nray not adequale ly penetrate

t ie l r i lv rvoven l rbr ics lnxde wi th h iSh' twis t yarns ' Cood penetrat io t lw" i l l r ;su l t f ront thc use of t l te proper ret r rd ing agent , to prevent

last s t r ike and pcrrn i t s low ex l raust ion. I f i t is necessary to

exieed ? loC, 5 0" /o comnron sal t should be inc luded for t l te last

30 minutes of the dye cyc le. VEREL f ibre c lyed in th is mannerca

bc dr icd i t r r rncdi r tc ly r t 82-138"C i l r ld rcstore( l to lu l l

lust te .

3. Delustrittg

After fabrics of VEREL fibre have been dried, they can exhibiic le lust r ine rvh ich is easi ly recognised by weak sharJe, dul l appcar-on. . uu, i harsh hand. Delust r ing of VEI IEL [ ibre c0n occur atwet-Drocessing tc tnperatures as lorv ls 60"C, and i t beconlesi r rcr i rs ins lv s ivere betrucen 600C ar ld thc boi l . Addi t ional ly , a i rt l rv i r rs c f l - r i incrcase the sever i ty of de lust r i r rg . l f de lust r i t tg occurs.trbric's of VEREL tibrc can be restoretl to norntal appearatlceancl character in any of severa l ways; for exanrp le, by exposure todrv s team or to I Io t 17 loC1 aqueous sal t so lu l iq .ns, Io l lowed byoroper c l rv ine. The use of dry heat in corrve n t iona\stock, package'

i t . i r r . loob o i tenter dryers, however , is usual ly the t r lost Prac- t ica lrvav of re lust r ing mi ld ly delust red VEREL f ibre. Dry ing the l ibreat b2- l38oC shloulc l conlp lete ly restore c lyed VEREL f ibrc to i tsor is ina l lust rous corr< l i t ion. ' l 'he f ibrc should bc kept nro is t be lorebci"ns dricd. I-ixposure to l)ot aqucous sillt solutiorls (20'50'/"),folliwed by drying at tlte ntaxiltlulu drying ternperalure., is.thenlost e[ [cct ive rvay of rc lust r ing scvere ly delust red vbl<rL l rbre 'The lareer denier VEREL f ibres r re nrore d i f l icu l t to rc lust rethan thd srrrallcr dcnier fibrcs.

430 431

B : S Y N ' I ' I I E T I C F I D R E S

(b) Blends ol VERDL ond jcctote

VEI{EL can be dyed and rcctalc Ic[1. rcasorrlbly clcirr t l lrouqhthc use of sclected neutral prcnrctall izccl <.lycs. If is lot nossibioto dyc thc ace ta tc and lcavc VDREL wh i tc . Any dyc l i ra t w i l lcolour ac€late rvjl l also dye VEREL. By propcriy sclectingdisperse dyes, unions may bc obtaincd on thcsc two librcs. I inecessary, thc VEIIEL can bc dycd to shadc by adding ncutralpremctall ized dycs which wil l not allcct the rcetatc. Cross-<tyc<lclTects on this blend are l inri lcd. It is possible to sclect coloursthat wil l dye acetate heavicr than VEI{EL. Thc VEIIEL can thcnbe shadcd with basic or neutral prcmetall izcd dyes for two-colourefiects. Such dyeings are, howevcr, dil l icult to control.

(c) Blends ol VDREL and Auylic

Because of the wicle variation in dycing bchaviour o[ dilTcrcutacrylic f ibrcs, it is not possiblo to nlf lko gcncull sltttcntcnls nborrtcolour cllccts on VEREL/acrylic bleuds.

(d) Blends ol VEREL s d Co o , and VE.REL ond RoyoVEREL blcnded wilh cellulosic fi l .rrcs pcrnrils a wirlc rirnsc orcolour c{fects, Such blends may bc union rlycd, cross_clyc-rl, orcither fibre can bc colourcd and the othcr lcit whitc. Cornbinr-tions of direct and ncutral prenretall izccl dycs cau bc applicrlfrom a single bath for unions or cross-dycs with good fasincssproperties. Dispersc dyes may also be used in thc samc bflth witlr(l irect dyes. Basic dyes can bc applicd in tlrc f irst of two bathsfollowed by direct dyes on the cotton or rlryon. Succcsslrrl pll lrrlruns havc bccn madc by dycing with basic and tl ircct dvcs inone-bath . Thc cornpr t ib i l i t y o f bas ic and ( l i r cc t dycs s l rouk l bcverif ierl

Bright. shndes of outstanding wct fastrrcss propcrtics can bcproducecl by first dycing the ccllulosic fibrs witl i napllrols an<llhcn topping thc VERIIL in a sccond bath with 6asic dvcs.Selcctcd dispcrsc or nculral prcmctall izctl dycs wil l lcavc cottorror rayon vhite or slightly staincd. Basic dycs crn also bc uscdfor colour and white ellccts whcn bright shlrtes are rcquircd.Sclectcd dircct dycs and naphthols, in thc prcscncc of cotiot orrayon, w i l l l c l vc VEILEL wh i lc . M i rny v l l anc l s r r lphur dycs w i l lstain VEIIEI- in thc prcscncc of cotton or rayon.

' l ' l ic high

I I A N D I ] O O K O F T E X T I L E I i I I ] R E S

conccntrrtion of sodium hydroxide used in vatc i r r rse VEI {EL to d isco lour .

dyc ing nray

(c) Dlcnds ol VDIIEL and Nylott

VEIIEL can bc dycd rvith sclccted basic tlyes lcaving nylon whitcor only slightly staincd. Nylon catr bc clyed with sclectcd acid oracid prenretall izcd dyes leaving VEREL whitc ol only slightlys ta incd . Un ions are poss ib lc by any one o f th rec n le thods :

Selcctcd ncutral prcrnctall izcd dycs rvith a nylorr relardiugagel)t to achieve balarcc.

Sclcctcd dispcrse dycs using a rctarding agcnt lor nylon toachieve balsncc.

a : s Y N T t . t I T t c F t | ] n E S

Prin(ilg

'l 'hc inherent flante resistance of VERIIL fibrcs tulkes thcrrr usclulfor, nrarry kinds of printetl tronrc ft,r,ristri,r!s.-.ii;iil;: ;;i,;;;ii;,i

llllllli:li:il riiln ffi ' "i'J1.:'n1]',,lfl;il.,, ?xiliii ;lliliii.?i,11''difli'J'il li,u,,'.T'ifi ;i''ilL'll, :lIl "l;, l,l"ililll j:i*:i:'*1iT,li ",tf-! li:fl::l'[],*i.,i:i"H.illll'l *llirulPrinti g Assistantsa d ltlcthods

VEI{EL nrodacrylic fibre is easilrrn(r neutrar.pre,nctariz.ed rryes. i,i;:'j:jl,il;li,illi:ili:i,iiili.:::ioe appt led to tabr ics | l radc fronr VEI{EL f ibrc. CJrrvcrr t iorrr lpr int ing -equipmcnt and nrcthods cnrr l lc usr, t l tu pr i , , f , i ,u i i i .varicty of ftrbrics rnrdc with VU{IL fibrcs

to I roducc o p l i I tu tt l ) i ckc | l c rs , h0rvcvcr ,

VEILllL rvhcn print irrg

t .

3. Combination of acid and brsic dyes applicd from either aonc- or two-bath method. Unions or cross-dyes can bcobtaincd.

(0 Bleutts ol VDREL and Polycstcr

This blend is uscd in scattcr rugs and knit goods- It is possibleto obtain solid colours by dyeing lhe VEREL ancl polyester f ibresseparatcly, and thcn blending ths l ibres.

In yarn or piecc dyeing, selectcd basic dyes ntay bc used tocrye thc VEIIEL only and leave the polycster relatively trnstained.Basic dycs wil l produce a rvide range of colours witb excellentl iglrt and w^sh lastness propcrtics. A l imiled range of coloursnray be obtained by using cithcr dispcrsc or neutral prentetall izcddyes.

(g) Blends ol VEREL and Wool

Scvcrat nlethods may be used for dyeing this blend. I ly usingsclected acid, chrome, or acid prenretall izcd dyes, the wool canbo dyed leaving thc VEREL fibrc white. l lasic dycs ntay bcused to dyc the VEREL and lcavc thc wool rclalively unstrined.Stain may be rernoved frorn the wool by means oI zinc sulphoxy-late formaldehyde reducing agents, without allcctirtg thc sltadcof the VEREL. Unions rnay be dycd with sclccted ncutral pre-mclall ized dyes. Retarding agents of various typcs have bcet'tuscd to control unions.

'frvo-batlr proccsses using acid and basicdyes may also bc uscd for dcsirable ulions.

Wscosity Control,' l 'hickcrrcrs arc uscttl ) r in t -paste - v iscosi ty . St rongly arr ior r ics l roul ( l not be use( l on [abr ics r r radc f rorr rrvith cationic dyes.

pI I ALl iustnrent- l l l addi t io

to t l rc usur l p l I - l t l iust r r rcn l a t l t l i t ivcs-

i,llf5t"*"n'" agerrt such as glvccrirc sloi,l,l l,;;rd.i;d io ii;;i;;t,ii

Drying ond Deucloping D),cs. Alt.cr thc ftrbric hls becrr printctl. itnr ry , t )e df lcd. l lus s tcp, l towcvcr , is not csscnl . i i r l .lne. (yes or p ignlcnts uscd to pr in t t l rc f r l : r ic : r rc I ixcd bvxtnrospl lcr ic s tcan) ingt t l lc usc of c l i r ic rs o, o t t , . r , tyc i , ,e , , i i i i i ; , , i is

rs .not necessary. Wl)cn le dycs havc l lccrr dcvc lo l lcr l . t l rc nr i r r t r ,dlaDncs l lay be scoure( l ar rd dr icr l . Dur i r :g scoui i r rg , s t l r i r r i lg r - r ft l rc ur)pr in^tc( l backgrour ld by ca! ior r ic dycs crr

bc i r r i i r r r izcr ' i l>vurc usc o l . r s t rongly anionic rc t r rdcr . Srrc l r rc tnr t lcrs lmvc r roc| lccr on ( l lspcrsc or ncutra l -prct | tc t l l izcd r lycs.

Pign,tutt Printing.. As pjgntcnt prirrtilg irrvolvcs lltc ust, of aur l ( l I rg agcl t to t )o Id )c p ig lcnt to t l rc f t t l r r ic , t l rc a l " l i r r i tv o l .I r tvr ( tua l t tDrcs lor lc p igt ) tcnt is not i l f : lc tor i r r Pr i r r t i r rg iv i t l t

I

412 433

,}}ff, F, F.F-F l' h h F h h h h h t, I, II I A N D B O O K O F T E X T I L E F I B R E S

such colorants. ' l 'he main consideration is that curing tenlperatures

an(l tin)es nust be kept below those which can cause the fibre toyel low.

Dles for Printittg VEREL

Each class of colorant has some advantages over others.

Cationic Dyes. These dyes produce vivid colours of excellenttinctorial power and good fastness. They are generally the bestdyes for printing VEREL fibre.

Disperse Dyes. These are less expensive than cationic dyes, butthc wash and sublimation fastuess ancl the colour brill iance arenot , in genera l , as greal as those of cat ion ic dyes.

Neutral-Prcnrctallized Dyes- Thcsc are usually colourfast atttleasy to apply, but are not as bright or as fast to washing anclsubl imat ion as cat ion ic dyes.

Resfu-lJonded hgDrc ts. Although easy to apply and econotnicalin l ight to mcdiunr shades, res in-bonded p igrncnls car l adverselyaffeit the hand, dry-cleanability and flanrmability of fabrics. Withcareful selection, however, these colorants give acceptable colour-fastness. Ily liniting the amount of coverage, most flarnnrabilityrequi rements can be met .

D e lus tri ng D uring S t eanling

Delust r ing dur ing steatn inB of VEREL pr in ted fabr ips is a potet t t ia lproblerr on ly i f the pr in tc( l labr ic is wet (o lher t l ian wi lh pr i r l t-Daste)

or if saturated steam is used to fix the dyes. lf delustring isencountered dur ing the steaming oPerat ion, the fabr ic s l roukl beexposed to a hot-so lut ion ( lO:20 g/ l ) in a wash box at 94oCarrit cooled slorvly tlrrotrgh subsequent wash'boxes. The fabrics l roukl then be d l ied in)n ledi r te ly at 104- l2 l "C.

A nrore clesirable solution to this problern would be to eliminatethe cause of delustring by drying the printed fabric prior tostearring and by using rvell-trapped steam to develop the dyes.Otrjcction:rblc clelustrecl spots nlay also occur ifcondcnsate tlripsonto thc fabr ic dur ing steatn ing.

S Y N T } I E T I C I : I I I R I ] S

Stripping

ll

Basic Dycs

Str ipp ing_or lcvel l ing of basic dycs can prescnt pro l> lcrns. Mostt lyes can be st r ipped l ronr VDl lDL, horvcvcr , bv u i i lu r corr rb i rxr_t ior r . .o f a dyei t )g ass is ta l ) t ( ' l rnadcl V - I 'nr i r tcx 6hcrn ic l r l ) . : tlevelling agent (Migrassist AC - 'l 'atratex

Chcrnical), and rrrroxidising agent or rctlucing agcut or both, tlcpcntlirrg on which(yes are used.

Dkperse Dyes

Most d isperse c lyes.can be par t i r l ly s t r ippcc l wi th 5_ 10 pcr ccntsoap chips at 600C. for -30 nr inutes. So( l iur l ch lo; i tc ; i i icornple lc ly

.s l r ip . . nr i r r ry t l ispcrsc dycs, ant l z inc su lphoxytnfclonr) i l luct rydc wl I s t r rp tc d isch:r rgctb lc typcs. Var iorrs r rorr - ior r icmaterials have bccn used succcssfully to lcvcl shadc<t <Iyciirgs.

Net ral Prenrctollized DyesSodium chlorite and sodium hypochloritc havc both bccn uscdto slrip ll lese dycs from VEREL fibrcs \.vjth good s cccss. MiuryoI the level l ing,agents suggestcd for ncutra l prcrncta l l izcct dyc 'son wool and nylon also work well on VEIiEL.

Finishing

VEREL fibre is used in a wiclc varicty of blcncls ancl fabricconstru€tions, each having dilrcrent end_usc rcquircnrcnls. Finish-ing techniques are selccled to suit particular riccds, and thcrc isno single finishing proccss which applics to all fabrics.

Resirt T.reattncnl

Rcsins bchavc on VEREL fibre as thcy do on othcr hydrophobicfibres, i.c. they simply form a coat on thc surfacc oi fn" nUr"or fabric. They do not crossJink or olhcrwisc react with thcfibre.

A blend of VEREL and ccllulosics nray bc succcssfully rrcntcdwilh rcsir if curing tinrcs and tcmporatur;s arc closcly confro cd.

434 435

I I A N D D O O K O F T E X ' T I L E F I I ] I I E S

n t a curing tenlperature of 135'C., for example,5 nrinutes nightbc the mininrum tinre to effect a cure. A curing temperature of149"C. nright require only lI minutcs for culing. Temperaturcsexceecling 150"C rvill cause VEREL to yellow, the extent of thecliscolouration depending on the length of time of exposure toelevated ternperatures.

The usc of rcsins or other finishes on fabrics clcsigned formaxinrutn flame resistance may sometimcs cause the labric toIose some of its inherent resistance to burDins.Slu'itrkagc ControlFabrics containing high percentages of VEREL fibre may belinishcd rvith good dimcnsional stability it they are relixcdcompletely by hcating in the finishing routinc. This may beaccomplishcd in a loop or airlay dryer, or sirnilar equipment, atlenrperaturcs up to 127"C. Stretching of the fabric during anyphase of processing should be avoided.ShcaringFabrics of VEREL fibre are easily shcared on conventionalshearing equipnrent. The fusing of fibre tips mry be a problenron dense cul pilc fabric, but this can be elirninated by passiugthe goods through the shear at a slowcr spced. lt is importcntthat the shear blades are kept sharp.SingcingVEREL nbre forms charred black beads on the fabric surfaceduring singeing. Fabrics containing a low percentage of VEREL,howcvcr, may be singed successfully both in greigc and linisheclIorms.

o : s Y N_I .

l :_ r r c F tu tu isfcnsile Strcngth

2,940 _3 ,290 k}lclrn2 G2,0oo_47,000 tb/in z.).

trloogaaion35-40 pcr cent, dry or wct.

Iilastic Rccovcty88 per ccnt at 4 pcr ccnt; 55 per cent at l0 pcr ccnt.lDit inl Modulus

247 .2 cNltex (28 g/clen)

Avcragc S{illncss

8.0.

Avcragc Toughncss

4.33 cN/tcx (0.,19 g/(tcl)

Yield Strcss5.83 cN/tex (0.(16 g/cten)

Yicld Strain

3.6 per cent E.

ComDliaucc RntioI . t 8 .

Spccilic Gravityr .37.

Iillcct ()f MoisturcRegain : 3.O-3.5 pcr ce0t.

' l l lor lt l Propcr(ics

StickinS \ylqcyarure.. Ig0_Ig5oC. Maxirrrurrr srfc irorrirrg tcnr_pera ture : l50oC-

ElJcct ol Lov TenrpcraturePhysical characteristics ntl intaincd lo cxlrcnrcly low tcnrpcnr-tutcs.

rclcrs to Va[ts] rype te:,

Finc Struclurc nnd AppcaranccA rvhitc fibrc, availablc as bright or dull lustrc. Sorne typcs arcrvailable in spul dyed black. Pcrnut-shapccl cross-sectioi. X-raydillraction patterns show VEREL to be a well-orientatcd, slightlycrystallinc fibrc.

Icrncily| 5 .9 - 22.1 cN/ tex ( I .8 . -2.5 g/ t lcn) , t l ry ;| 5 .0-21 .2 cN/ tcx ( | .7 -2.4 g/ t ler r ) , rvct .

STI{UCTURE AND PROP'l hc infornration which [ollorvs3D/F lust re f ibre.

t- l' I ' I

436 437

I I A N D B O O K O F T E X T I L E F I l ] R E S

E[]ect ol IIigh Temperature

Regular f ibre: shr inkage in boi l ing water , 0 .2 per cent ; I lo t a i r(140"C), shr inkage 4-6 per cent . A rapid change of proper t iestakes place, with fall in tenacity ancl modulus, and increase inc longa t ion.' l 'er rperatures exceeding l50oC wi l l cause VEREL f ibre toyellorv, the extent of discolouration clepending on the length oftime of exposure to elevate(l temperatures.

FlcttrunbilityVEREL fi1.:re has a vcry good flame resistanbe. lt is very dimcultto ignite, and is self-extinguishing. It leaves a hard black char,and docs not drip.

,VEREL'

438

3.0

2 ' 5

2.O

t . 5

t ,o

0.5

STRATN (% ELONG^TION)

f t ' l l ' ' l l ' ' l l " i l " i l lnnnfnnF'Ennnnl8 : S Y N , r l t D 1 . l C F I U R E S

Ellcct of A8c-fhcre

is virtually no changc in thc propcrtics of VEITDL titrreover an extended period of t imc.

trrtcca of SuntightVEREL,has good weathcr ing charac tc r is l i cs ; i t i s bc t tc r in l l r i srespcc t lhan any na tura l f ib rb and most . o [ lhc sy r r rhcr ic t iU ics .inclLrding viscosc, accrntc, polyanridcs r"r' l ;"iy;l;;;;.

'" "" '"" '

Affer 50 weeks' outdooi "^posur", VEI{E.L rctails loodstrength and elongation unclcr conditions *lri"t, .1";a;;;;d;i;wool and cotton.

Chemicrl Propcrtics

AcitlsExccllent resistance even at high concentrations,

AlkalisGood general resistance. Alkalis unricr modcratc conditions havcno clfecl on tenacity, but causc somc discolourrtion.

Getteral

Y-:.la_!, h". a lr igh degrce o[ rcsisralcc to a wiclc rarrgo ofcilcn)lcals.

Ellcct of Org:tnic SolvcntsVEREL f ib re res js ts a l l d ry c lean ing so lvenfs and n los l conrn lonorganlc solvents. It dissolvcs in wafln acctonc,

Insectr

Not attacked

Micro-organisDtr

VEREL fibre is not attacked by mildew and othcr nricro_organisms. It is unalTeclcd after being buricd for fz *."i ir ' i ,moist,, biologically acrivc rivcr loam at 25.C. Corto,, A1"oiniu..,after 6-7 days iD the same test.

Electrical PropcrlicsDic lcc t r i c

.s t rcng th cxcccds 1 ,500 vo l ts / rn i l ( l i l r r r ) ; d ic lcc t r i ccons tnn t 410 a t 60 cyc lcs .

439

I I A N D B O O K O F T [ , X ' I ' I L t ] F I U R E SAllcrgcnic Propcrl ics

VERIIL l iblc is non-al lcrgcnic.

l lcfrrct i lc Indcx

1.533. VERE,L fibrc exhibits practically no bircfringcncc.

VLITI ]L IN USE

Gcocrtrl Cltrrac(cristics

VEREL- fibrc po-ssesscs tnuny i l l tractivc chanrclerislics from tlrcpornt ot vtew ot gcncral tcxti le usc. It contbjnes a soft. warrnhlnd_lc with thc captcity for absorbirrg moisture that ";; i".1;;conr to r t i tb ic wc f l r . I t h s a good rv l r i l cncss and c lycs cas i l v anc lc cc t rvc ty , and n lay bc e lec l ropo l i s l red to i l l l i gh l l i s t re .

lt,I echani cal I'ro part icsVff{EL is

strong, loUgh fibre. Its nrecltlnical propcrtics arcor urc slmc or(lcr i ls thc avcragc typc of acrylic f ibrc. Tenlrcitv.c long i tUon a t ) ( l c l i t s t i c rccove ly a rc adcqu: r tc fo r norn ta l t cx t i i ci lpplcarlons, xnd alc nol affcctcd significantly by walcr.

Spccific G ruvityThc spccific graviry of VEREL fibrc is relarivcly high (1.37).

Moisture

Thc nro is t r r rc rcgr in o f VEREL f ib rc i s -unusua l ly h igh by cor r r_prrisorr rvith other potyacrylon it r i lc f ibrcs, anrt this is allrn rpor tan t l ca tu rc o f rc f ib rc . l t n rakcs fo r g rc i l t c r con t fo r t jnrvcrr, cspccially in fabrics rvoru closc to thc ski\ O"spii" if i i ,chnrrcrerisric, VEREL is nor advcrscly off".r"A Uvt,uoL'tri". i i ."nrechanical propc-rl ies being only slighity affectcO.'Ralr;i l ;; i ;goocl dirncnsional stabil ity and wrinkle resistancc'l'herntal

Propenies

VEITEL is a t l renr rop las t ic f ib rc , w i t l r r fa i r l y lo rv so l tcn in Ile i rpcrr trrre (1,20- l25oC) by conrpar isorr * i t i , r . ivf i . i , r r r . r lan(t carc r)nrst bc takcn i l : r l l proccsi i r rg rulr ic l r i r ruoluts c lcvaic, ircnr pcr i l tu rcs

- I r - l r l l r t r l r l

440441

I l : s Y N T l t E f r c F l t r n E s

, , . ,1 h. f , - l : l -n"u ' , | l "b i l i ry ot vEJ{EL is : r g lcr r t adv lnt lgc, pLr t r ingl lUs l r b re I n to a l t r ) os t l he san t

*;::j;f"|il ;;ii,,';;.J"1:",::lll,"'.,il"J#i'i:.ili:l'uj,., f ilillnvi rctntrcnt ql Corul i t i on sVEI {EL f ib rc l tas cxcc l l cn t rcs is tancc lo su t r l ig l t l , agc ing ar rugcncral wcl lhcrirrg conditions-bv insecls ";; ,rrt i l ;;; i [ ')rrt

is cotr]f lctclv rcsistlrrl lo ir lt irck

Chunical Rcsistonce' l

l t c rcs is la lcc o f VEt {LL f ib rc to n tos t ty |cs o f c l rc r r r i c l l:l:]:jlli'lS acid.and arkati, is cxccucnr. rr wirr ritirisrai.l ;i:;i;,ii:;i;;cor(rrrrors . 'd is ,o l a[ Iccrcd by thc chcnr icrr ts i rsct i r , , . i i l , i i i i l , iI r \ t i lc . I ro^ccssing. Norrc oI thc corrrrrrn r l ry .1. , , ; i ; , ; . _, ; i ; . , , i ,i r l l cc I lhc f ib rc .

Pilling Resi.trance

yPI IL n9r " cxh ib i ts l i r r l c l cndcncy to rv r ( l s P i l l i r rg , cvc

inI rDncs n ladc w i lh low lw is t ynr ls .

lYr|shing

ili':iliJ:,1,'"t,|#'"ft I,,T"-i',ll.A, of,ll,l:u-.,_!r.,,*cr,i,,c,or clctcrgcnr. C"", r"

-,Lri"ir,,"lii"ril i"'rusrng

a neulrirl so.p

Drying

Fabrics.nray l.:c trrnrblc <Jriccl or drip dricd. Elcv:rtcd tcu)l)crltrrrcsshould bc avoidcd.

Irouing

,fi!ri1 ilol..t 9.iionect, prcfcrabty using a danrl ctorh, wirtr rtrcrron- i t_ 'synrhet ic ' sct t ing. Mirximrln i r tc i ror i inf" i ; , ; ; ; ; ; , , ; ; :::_]?9-C Care shouttt b; takcl ro rVoirl distoJi,r! ,i;;"i;;; i;produce a glazcd effect.

t E f'|| I l''i l'l l''i t fl li E E E E t f: f: f: H Ir l'li l

I I A N D A O O K O F T E X ' T I L E F I B R E S

Dry Clcrning

I:abrics of VEREL f ibre may be dry clcancd by the normalnrethods. The f ibre is not affccted by thc usual dry clcaningsolvents.

End Uscs

Pilc Fabrics

Thc softness of VEREL fibre, cornbined with whiteness. excellentflanre-resistance and controlled shrinkagc have provcd advan-tageous in the production of pile fabrics. These include both thewoven and knitted types of construction for a wide varietv ofcrrd uses ranging front coatings, l iner fabrjcs and floor .ou"rings,to trimmings for collars, cuffs, boots and shoes.

The availabil ity of VEREL in both regular cross-section andribbon cross-section forms has been put to good use in ther l r r ru fuc tu re o fs in ru la ted fu r fabr ics .

Pile fabrics nrade fronr VEIIEL provide warmth withoutrve igh t , assoc ia ted w i th so f t , a t t rac t i ve i ra r rc l le rn r l q rer t conr fo r t .

Knit Cootls

The abil ity of fabrics oI VEREL libre to rctain a solt handafter repcatcd washing and drying is advantageous in knitwearsuch as sports slrirts, underwear and children's garnrents. A blendcontaining some 25 per cent of VEREL with cotton realizes theattractive properties of VEREL at an economic price.

7' hr e e- di nrcnsi on al Fabrics

The use of VEREL shrinkable l ibre nrakes possible the productionof three-dinrensional fabrics with a wide ranse of blister anclpucke r e f fec ts .

- \

I nd ust rial A p plications

Tltc rcsistancc of VEREL fibrc lo nany types of chemicll,inc lud ing ac ids and a lka l i s , has brought i t many app l ica t ions i r rt lre industrial neld. It is used for f i l ter cloths, protective clothing,etc.

Dropcry; U pholstery

VE-ltEL fibrc provides cxccllcul drapery ancl upholstery fabricsrvhiclr havc the spccial advantagc of f ir i rcsistancc.

442 443

A : S Y N T T I E T I C F I B R E S

Catpcts

VEREL f ibre.has many valuablc characlcrist ics lo ol lcr to lhccarpet tradc,_ including good abrasion rcsistancc, g"oJ ;";"r; ; ; ;

l^"-1.ll l,l]dl rangc of dyeabitity, high resistancc 'i,

*iii"e ;;icase ot cleitnl | lE-

-.!urn"tt reta.in lhcir appcarancc and tcxtlrrc ovcr lorrc ncriodsor scrvice, and tests havc shown vEl{lL ro bc bcrtci ifi,,;;;;;iin this respcct.The soil resislance of VEREL is excellcnt, and it is clcancdeasity and cficctivety wjrh lhe aid .r ;i;i;i;i;;;;;;: '];

wear tests . VEREL carpets gavc 20 to SO p.r . "n i -gr"nt" iwear life lhan acrylic fibies.

-

Carpets of VEREL fibre havc a crush rcsistancc simihr towool. They_ display excellcnt stain resistancc ",Jn;;; ;;;;i;;;and are inherently nlothproof and rot_rcsisti[s.

Note

Lastrile. (F.T.C. Defrniti)n )A marruf rc tured f ibrc i r r wl r ic l r . the f ibrc . for ru i r rg substar :cc is acopolynrer of acry loni t r i le r r rd a d ierrc (suc l i as Uuta, t lc , io jconrpos.ed..of not more than S0% tur ot t"oii-iijZ, t,i;;j;il';lacry loni t r i le uni ts .

l.

I I N D A O O K O F T E X T I L E F I B I I E S

POLYVINYL CHLORIDE FIBRES

Fibrcs spun from polyntcrs or copolymcrs of vinyl chloridc:

CH2 : CHCt ----->

VINYL CHLORIDE

INI RODUCTION

- - - cHr - cH-cH2-cH - - -

clc tpouvvipvu cHLoRIDE

Polyvinyl chloridc (P.V.C.) was 0rst tnade by the French chcnristI-Ienri l iegnault, who prcparcd and polynrerizecl vinyl chloride in1838. Whcn all kuown polytners came under examination aspotential sources of synthetic l ibres, during the early part of thcprcscnt ccntury, it was natural that polyvinyl chlolide should bcanlorrg lhosc considercd.

I\ ' [any atlen]pts were made to dissolvc polyvinyl chloride ardproduce fi lanrents by extrusion of solutions through spinnerets.l lut thc polynrcr rvas clif i ictrlt to dissolve, alrd solvents suitablafor usc ou a corrrmcrcial scalc were not discovcred.

Alr experirrcntal P.V.C. fibre vr'as spun in Cermany in 1913,but did not come into largc-scale procluction, During tl)e ycarsfollorving Worlcl War I, atten)pts rvcre madc to modify thcpolynrcr in ordcr to make it morc readily soluble, It was foundtbat. this could be achieved by introducing a surall proportion olanothcr vinyl compound into the polymerization, forming acopolyntcr in which the nrolecular chains did not pack togethcrso closcly rs in lhc case of P.V.C. itsclf. Experinrental l ibres wercrnade lrom a copolymer contaiuittg 85 per cent vioy{ chlorideand l5 pcr cent vinyl acetate in Gcrmany in 1928.

In 1934, jt rvas found that lhe solubil ity of polyvinyl chloridecoulcl also bc incrcased by chlorinnting lhc polynrer. The largechlolinc atonrs introduccd at irrlcrvuls aloug the.P.V.C. rnolcctrlcshad an cllect similar to that of thc acetate groups in the copoly-nrer, reducirtg the degree of attraclion exerted between the longnrolccules and incrersing solubil ity.

'Pc Cc' f ibres, nrade frotn chlot' inated P.V.C., were introduccdin Gernrany in 1936. Thcy achicvcd sonrc l imited success, btrl.havc ncver rrradc rcal progrcss in thc gencral texti le ncld. In 1937.

M4

l . r

44s

t ] : s yN. l | | t i . t I c F t l rRus

lib,rcs. spun frorD a copolyntcr of vinyl clrloritJc arrcl vinyl acctlrr:,callcd 'Vinyon',

wcrc prodrrcccl jtr lhe U.S.

Iu 1940, French chcmisls discovcr.c(l thlt I,.V.C. itsclf coulclbc clissolvcd irr a rnixlurc o( acctonc lrrcl crrborr disrrlptrir lc,:rrrttthis solution was suitablc for thc pr.r:t lrrction of p.V.C. i ibrcson il conlDcrcirl scalc.

P.V.C, fibres arc |low lrri lrufi lcturcd in a valicty of for|lrs arrtlnrodil ications.'fhcy have achieved a l inritccl succcss in thc tcxti lctradc,.but their range of applications is rcslrictcd by thcir lorvsoftening poiot. Many P.V.C. nbrcs wil l soltcl at tcnrpcraturcsas lorv as 70'C.

On the other hand, it.V.C. fibrcs havc churactcr.istics rvhiclrIrrvc crcatcd a clcnrancl Ior ihcnr in ccrtain rpplications. . l- ltcy(lo not burn, anrl havc a lrigh rcsistlncc to nrany chcnric:rls.. l.hciil cn ( lcncy lo shr ink i l l r c l i l l i vc ly lo !v l cn lpcr i t t r l . cs i s r r l r t l c r rsc o fr l l l r c p to ( luc t ion o f h ig l r b r r l k y l r rns ,

]'y|r::s oF pol-yvtNyl- cr.l!.glrpE I|lryl:ibres are prorlLrccd front 100 pcr ccnt polyvinyl chlorit lc, frorrrcopolyrrers contrrining srnall proporlions o[ variorrs s".o,.,, i ",,,,.,-pooents, and frorn polyvinyl chloridc rvhich hirs bccn clrcnricll lyn rod i f ied , c .g . by ch lo r in r t ion .

Thcsc fibres arc availablc in a vilr iety of fornrs, c.g, ofcontrolled shrinkage, to suit particular applications.

' l .hcy rrc

produccd as conlif luotrs l l lamcnt yarns, sttplc Iibrc and tow.

In tl)c scction which follows, polyvinyl chlori<lc fibrcs l lc corr-sidercd under thrce typs classifications, as follorvs:

Polyvinyl Chloridc Fibrcs (100 pcr ccnt I).V.C.)Vinyl Chloriclc Copolynrcr IribrcsChemically-Modificd Polyvinyl Chloridc t:ibrcs.

( l )(2)(3)

NOMENCLATUI{E

The name 'Vinyon' rvas rcgistcrcd i ls aCarbiclc Corporalion for thc fibrc spun

t rac lc nrr rk by Union Ifronr a copolyntcr of

i

i- 1 , - - . 1 , - -

L E N E E T Ti .

l r N D l l o o K o F T E X I I L U l : l l l R E S

vinyl chloridc and acrylonilri lc. -fhis pllft icul r f i lanrcnt yurn

rvas dcsignated 'Vinyon' N.'Vinyon' N was subsequently follorved by anolher type oI

polyvinyl chloride fibre, called 'Vinyon' HH, which was spunlronr a copolynrer of 86 pcr cent vinyl chloridc ancl 14 per ccntvinyI rcctatc.

'fhc 'Vinyon' lrade rnrrk was ncvcr cD[orccd by UniorrCalbidc, and it rvas rclcascd for gcncric usc.

'f l)e lcnr wus

acloptcd by the U.S. Fedcral Tradc Conrmission as au ofl icialdcfinit iou lor f ibrcs of lhe polyvinyl chloride type.

Fcclcrol 7'radc Cotrrrtrissiotr Dcfi tiort

The gcncric ternr vi,ryo,r was cstablishcd by the U.S. FcderalTradc Connrission for f ibrcs of the polyvinyl choride type, thcoll icirl dcfinit ion bcing as follows:

Vitryott. A manufacturcd l ibre in which the Iibre-fornringsubs t ncc is any long-cha in syn lhe l i c po lymer composcc l o frt lcast 85 per cent by wcight of vinyl chlolidc u[its(--cH,--cHcl-).

C hlorolihre-l ' lre

lcrfrr chlorofibrc is also widcly used to denoto polyvinylchloride fibrcs as dcfincd by thc Federal Tradc Comnrission. Thislc r rn has thc advantage o f avo id ing any .poss ib i l i t y o [ con fus iouwith the trade namc 'Viuyon'.

( l ) PoLYVIN' l ' �L CHI.ORlDE I : l I I ILS\ .(lo0 PER CENT I,.V.C.)

IN ' f RO DUC' f ION

1'he production of 100 per cent P.V.C. libres has made steadyprogress in a few countries. The Frcnch firnr of Rhone PoulencTextile has, in particular, persevered with the developmentof thcse fibres. The first P.V.C. fibres rverc sDun at the' l

ror rv i l lc+r t -Lhrro is p lant in 1949, ant l by l9?6 sor i rc 9 r r r i l l io lkg oi libre rverc being procluced annually.

446

t t t t h t E h h h h h - l : _ h lo : : i Y N t I t t c t : t n l { L S

_ . l r r I t : r l y , by 1967, Soc ic t : r l l o lynrc r rvc rc p ro t luc i r rg . l r lov i l .P .V .C- f ib . res i r r a phnt rv i th n c lpnc i ty o f 4 r r r i l l i on k , l pc i l tn r , , r , ,and App l icaz ion i Ch inr iche Soc ie ta pcr Az io r r i (A( )SA) bcr lnproduc ing 'Leav in ' I> .V .C. f ib rcs in a p la r r t rv i th a cap ic i ty "o f5 r r r i l l i on . kg- ,per ,a r rnunr . I , .V .C. f ib rc i rvc rc l l so p r tx l r rcc , l i , rJapan l r rd

. i r r West Cer r r ra r ry . I ) roduc t ion i r r l t r r l y a n r l Wc s t Ccr r r ra r ry

subseauen t l v ceased.Thc'progrcss of lr.V,C. fibrcs sincc 1949 lras trcor slcil( lv ri l t l tcr

lh i rn s l )cc tacu l i l r , f lnd t l t c usc o f thc f ib rc fo r l l rgc -vo lu rnc tcx t i l cpplications has bccn rcstricted by a lack of stabil i ly to l lctt rud

to dry clcaning solvcnts. 'fhe

attri lcl ivc clttraclcristics of I,.V.C.fibtcs (scc pagc 455) couplcd with tlrc lorv pricc o[ thc polynrcrlravc, ltowcver, cncouraged produccrs Lo scck rvays oI ovcr-coming the fibre's dc{iciencics in ordcr to cxtcncl thc rantc ofi t s l cx t i l c app l i ca t ions .

- I Jy_ .1964 rn . in lpor tan t s tcp Ib r rv l r t l h : r t l bccr r t l r kc r r I ry l l r cf i r r r r R l ro r re Pou lenc l ' cx t i l c , w l to t leve lopc t l a b lc r r t l o l po lv r r rc rscons is t ing o f s tandan l I ) .V .C. a r : r l c l r lo r in r tcc l I ' .V .C- io ob tu i r rbe l te r d iDrens iona l s tab i l i t y a t h igher tc l | r l ) c ra tu rcs , c .g . bo i l i r rgwa ter.

PRODUCTION

Monomcr Syntbcsis

Vinyl chloridc is producccl in vcry largc quantity for thc procltrc-t ion o f po lyv i r ry l ch lo r ic lc p las t i cs , nnc j f i t rc n , , i , ,u f " . r , , r " ,n .1" ,usc o t on ty a sn)n l l p i r r t o f thc ou lpu l . fwo rou tcs l r rc cor r rn ron lyrused.

(a) Acctylcne and Ilydrogcn ChloridcAcc ty lcne is . rcac tcd w i th hydrogcn ch lo r ic lc in lhc p rcscncc o f,r r ' l lcrcuric chloridc catalyst

CH=CI.I + I-ICl->CH, =CHCI

447

I I N D R O O K O F ' T D X T I L E F I I I R E S

(b) Etlrylcne arul Chlorine

Etltylere dichloride is produccd by rcaction of etbylcne withchlorine (l). This is then hcated under pressuro rvhen hydrogenchloridc is reledsed, leaving vinyl chloride (2).

( l ) (2 )CH, =CH, + Cl"--+CH,CI.CH,CI-+CH,.:CHCI

l'olyntcriza{ion

Vinyl chloride is polymerized typically as an aqueous emulsionin autoclaves, under pressures of 45-50 atlnospheres and atenrperaturc of about 65'C. The polyrner lorms a suspcnsiou iuthe water, and is recovered by spray dryiug.

Dlxrnrt lg

P .V.C. f ib res nray be spun by dry o r n re l t sp inn ing processes .

Dry S pi ning

l'.V.C. is dissolvcd in a solvcul, e.g. acetone/carbon disulphidcnrixture, aud tbc solution at 70-100"C. is pumpcd through spin-nercts. The line jcts emerge into a stream o[ hot air, thc solvclltsevaporaling to leave solid l i laments of l ' .V.C. Thc solvents arcrccovcrcd and re-used.

This process is used almostspinning of textile-grado P.V.C.

exclusivcly for the conrmercialfibres.

Ir'I clt S pinning

Molten P.V.C. may be spun by extruding it through spinnercts,bul the spinning temperaturcs cannol be raised high enough topermit of the production of f inc denicrs necded for staple andtow. P.V.C. begins to clecontposo at about 200'C., and belorvlhis tcnrpcrature the viscosity o[ thc moltcn P.V.C. rcstricts ihcfincncss of thc cxtruded fi laments to a dianrctcr of about 0.2 nll).

448

- t - 1 - l - l ' I

449

a : S Y N T i I D T I c F r o R E s

t ) l rocEssrNc

'l he infornration rvhich follow

i:ifi :i;i li' iih: i"i1:* i;",ii"i,i.ll,.','iiX,,:f,i,l,t:,1,.",$ jllii;LX: Standard p.V.C.

ii'":f3:'..61,i,X;';.i illl:;:;li.u n " .:'iii#il,ri{,iixi':,xdllliii'i:llll"iisc i' roirins warcr ( s5%)'l letractyl . ' :

Sraplc f ibre * i t lL sf i r i , i *gl cf iarrctcr ist ics i r tcr .,ii!i!f,ii :{i:",,m"iit,i:::xrfit* ;:rljit;i_, ;",,thcrn la l s tabi l i tv_'Fibravyl'ZC: Sirrinkage in boiling w tcr 25_30,/o.

Dycirrg

(' )' " il! : !,,:;,,[X!"" J i,? !1, li ii, ! "'' " r h t c n d s )''l' lre

standarcl proccdure is to

*:,?,"ili:$i j"'";"li:"ll ll :fij,llxl;"l''fiL': ii{fi:lif l:(2) 'Thernovyl' (100 per cenr or blends)' l ' l r

e tcchrrk ; r res t lescr ibct l above

[aeiq1;:*; [ii:rr*t,j rilul, n,]i[ {nli:,iiLi,.::,,Ti:'#l::;;tl[: j j lij:., lL "ri -';;irr,iji',.,ii.' i'ir,]iiii,, r.,j'::'jl'""."il] " j;-oli 1",i,: ;?,:i' J i,i"ln l:l i:'; J1,', i r i s c o' r, r,,r, r r v

(3) 'Fibravy.l'LX or ZC (100 pu cent or blctttls).

Shriukqe Conditiorts.' l ' l te

tenrperature condi t ior :s usct l [or shr i r rk i g t l rcsc [ ibrcs

il"iill''l,ilil,'"ji;tfi llr,::l;:t ll,-l;,;,I:ill.';i 1f,il1-l

F

[F, t t f t t t t I F, l'}}] H l'' F- F,II

I T A N D t r O O K O F T E X T I L E F I I ] R E S

Resisr Dyeing; Cross DYeing

P.V.C. fibres resist most of the types of dyestuff used for dyerngnatural fibres, and resist or cross dycing eflects are obtainablein blcnds.

Print i !rg

"l 'hcrrnovyl' ZC nray be printecl cffectivcly witlt clisperse clyes,convcnt ional s teanl ing being a l l that ls requi rec l to set the ( lyes

SholYcrprooIng

P.V.C. fibres are hydrophobic, but water wil l neverthelesspenetrirte through thc intersticcs of a cloth made lrom thcm.P,V.C. fabrics nray bc showcrproofcd by mcans oI the standardparaffin rvax type ageuts, with or without the addition ofaluminium salts,

Wa(erproofi g

P.V.C. fabrics may be rendered completely impermeable to water

by the application of a suitable coating, and all forms of standardcoating agents may be used. Thcre are advantages in using a

coating which rvil l have the same non-Ilammability and resistanceto dcgradation of the P.V.C. fibres, and special matcrials forthis purpose'are available.

If rubber coatings are required, it is best to use a self-vulcanizing latex at low tcnperaturc, rather than a process which

requ i res vu lcan iza t ion a t tenrpera tures above 70oG- for cont inuous[ i l i rnent o r 'F ib ravy l ' , o r l00oC. fo r 'Ther rnovy l ' ZC.

llondirg

Special adhesives are availablc lor the bonding of P.V C. fabrics'

t l igh'bulk and Sltrinkage Treatments

l ' �.V.C. fibres of the shrinkable typc rvil l undergo a high dcgree ofshr inkage rvhen heated to appropr ia te tenrpera tures , and th is n lay

450

t , tB : S Y N T I I E T I C F I B R E S

bc user l . [or creat ing l )u lk r r r r l rc la tcr l c l fccts , i ls i r ] t l rc c i lsc o l .rucry l ic l ibres.Shrinkage. n]ay be brou8ht about by dry, wct or slcarni|c

trcatnlcnt, the -choice dcpending upon il," nliturc of tf," noo.l.il !

o '1 " i , . : r , r t rs essent ia l to carry out thc t rcr tnrcot as uui [ornr lyas Dosslble-

, I iry treatmcnt may bc carrictl out by subjccting thc goods to

Itot air in a stcntcr. Steanring nray bc acbicvctl -on

n'"yli, i , l",oner o r tn an enc losed cbambcr .

Wet treatments are carried out on thc j ig, etc., thc tcchui<ructuscd dcpcnding on tlre naturo of the gooG. y"r,r. "ro tr"^i"Jil hank form, and piecc goocls arc in opcn width, scwn cnd (oeno. Alter treatment, piece goods may be passcr.l lhrough thcstenter to smooth oul the fabric and sct the rcquirctl sbri-nklac.

Shrinkagc carricd out on mixed yarns, doublci u"",, o, u"ir.sprrn frorn blcnds ot p.V.C. r,vith otl icr l lbrcs cr.. l" i n i i i l fr-,f ' .oi""of . bulking. Sbrinkagc carricd out on fabrics ;i l k;; i i"J;;;;brings about a.tightcning of tbe yarns, anrl this rnay b" u.]"d toaqvantagc to obtain various cffccls depen<.ling upon ihc conslruc_tion of the fabric.

l. Fabric witlt,Varp ol One Moterial and Welt ol AuorherWhen fabrics are made with p.V.C. we[t, for cxanrplc, andcottoo warp,_ the shrinkage of the p.V.C. produccs a fnbric whichrs very trgbuy packed and very strong. Fabrics of this tvne arcused ror.motor-car hoods, sports clothing and rainwear: t i icv arevery reststant to tearing, are showcrproof and dirncnsioitallystable.

Very dense velvets (collar vclvets) mry be ntldea relvet of normal construction, but woven withP.V.C.

, J\gw lypes o[ jersey trave bcen crcatcd by knitring p.V.C. on

rnreumK machrn-cs together with olher typcs of yarn (cotton,

I_o.!j]. rafon, uylon), and shrinking tt lc kr)irrcd fabric during

|lnrslrlng.

2. I{orrrogeneous Fabric nnde with Mixed Doublctl yarnsShrinkage of the P.V.C. yarns in this casc crcatcs a bulky fabric.3. Ilontogcncous Fabric nade vitlt Dlentlcd yarntThe ellects of sluinkage in this casc are similar to (2), but thc

451

by s l r r ink inga ground of


gcneral appearance is lhat. of a tightly packcd plaiu cloth wovcnwith bulky yarns. Additional eflccts nray bc obtrincd by raisingthis type of fabric.

4. Fancy and Cloquc ElJectsShrinkage ellects may be localizcd by using the above techniquesas pattcrns in the fabric. Using a plain fabric as a basis, fabricsrvith designs in relief, cloqucs, plaited weavc, knop eflects, etc.,may be produced.

Shaping; MouldiDg; ErnlrossingTho thermoplastic nature of P.V.C. fibre, and the low temperatureat which softening takes place, are put to good use in shapinglechniques which are used on labrics containing P.V.C. fibres.

Fabrics corlsisting totally or in part of P.V.C. libres such as'Fibravyl' LX nray be shaped by heating thern in such a way thalthey shr ink on io a former.

Fabrics rvhich have already been shrunk in the piece, or fabricsnrade fronr therrnally stabilized libre such as "l'hernrovyl'LX nraybe enrbossecl or nloul(led under pressurc, with or withoul thehelp o l heat .

Using tho 'shriuking-on' method, il is possible to cover flexiblemetal or rubber tubes, electrical conductors, ctc., with sleeves ofP.V.C. tubular fabric, and then to shrink the cloth on to the tubeor wire it covers

On the other hand, by moulding fabrics which have alreadybeen shrunk, it is possiblc to make a range of useful articlesrvhich are unallected by humidity, such as loudspeaker grilles,upholstery and car fabrics.

STRUCTURE AND PROPERTIES --,.'(l lased on continuous filarnent)

Finc Structurc and AppcaranceSmooth, rod-like fibres, of ncar-circular cross-section.

Tcnacity24-77 cNl Iex (2.7-3.0 g/den) , wet or dry.

Tcnsi lc Slre Slh

32-36 kg/mm2.

452

l F - |

t

j

l l[ ' L ' ] L l n 1 !

I ] : S Y N T I I E T I C F I D R E S

li lonS:rl io| l

I l-20 per ccnl, wet or dry.

Spccific Gravity

1 .4 ( " I 'hc rnrovy l ' ZC: l .3 t r ) .

liltcct of l\toisturc

The-. watcr absorption is virtunlly nil, and thc fibr.c docs notswcll in watcr. Moisture has no cllccl on mcchanical pruri.rt i"a.

flctntal Propcrlics

Shr i r rks on heat i r rg above 70oC. l " l hennovy l 'ZC: i l l )ovc l00oC. Ii l s the ex ten( led nro lecu les tc r )d to rc tu f l t to thc i r p rc -s t rc tc l iconfi l luration.

. At highcr tcnrpcraturcs, softcning contintrcs, urrd dcconrposil iorrbcg ins a t about 180 'C-

I;lontnability

P.V.C...f ibrcs arc r'nhcrcntly non-flu rrr nra blc. ' t-hcy

wil l not brrrrr.nor \vrtt they cntit 0atncs or rclclse nrolten incantlcsccnt dronscapable oI sprcading a firc on combustiblc nralcrials-

When subjccted to an intelse {lanre, fabrics nratlc fronr prrrcP.V.C. f ib rcs w i l l d is in tcgra tc , bu t thc rcs iducs n ,ny t " tuu i t i " jDy , ranq lo r thcy arc no t ho t . l ' l l c rc i s , t l t c rc fo rc , no r i sk o fburn ing .

ItlJcct of Low I-a11pst t1r,r.P.V.C. l ibres rctain their f lcxibil i ty and strcngth at lcnlpcraturcsas low as - 80'C.

Thernrul Conductivity

1 4 x l 0 - 2 1 w . n r - l . K - l ;

I i f lcct of Sunlight

Excc l l c r r t rcs is lancc . yarns cxposcr l to d i rcc t s l rn l ig l ) t los t l0f : , r

" " | : o , t c r r . s l rcng th n f tc r 5 r r ro r r l l r s .cx l )osr r rc , l5 pcr ccn ta l l c r lu DrontDs ' cxPosut .c , and 25 pcr cc r r t l r I t c r lg rn ( ) r r ths .cxposurc.

451

l ' r ' r '\ \ t

H A N D D O O K O F T E X T I L E F I I ] R E S

Chcmical Propcr(ics

A citls

No eflect. The fibrcs remained unharmed, for exanrple, alter4 years' steeping itt concentrated uitric acid, sulphuric acid oraqua regla.

Alkalis

No ellecl. The fibres remained unharmed, for example, after4 years' steeping in caustic soda or caustic potash (50 per cent).

Getteral

P.V.C. fibres have outstanding resistance to a wide range ofchemicals, . including bleaches, urine, perspiration, reducingage0ls, oxidizing agents.

Eflcc( of Orgnnic Solvcnls

Alcohols, ether and petroleum hydrooarbons do oot affect P.V.C.libres, but the nbres are swelled by toluene, trichlorethylcne,bcnzcne, carbon disulphide, ethyl acetate, acetone, chloroform,methylene chloride and nitrobcnzele. They are also a[tackedby pbenols.

15ELoNGATToN %

I'olyvinl,l Chlotidc Fibrc: Co linuous Fihntctrl

454

l 'r F, IB : S Y N I ' I I E T I C F I B R E S

Itrsccls

Completely rcsistant.

Micro.organisms

Completcly resistant.

trlectrical Propcrtics

P.V.C. fibres have a high dielectric constant.

Allcrgcnic PropcrtiesP.V.C. tibres do not cause any irritation whenthe skin.

in coutflct with

P.V.C. FIBRES IN USE

Gcneral Charactcristics

Fibre StructureI ) .V.C. f ibres. l re corr r r r ronly rat l ler fcr turc lcss arr t l ro t l - l ike i r rsr rucrure, and in th is rcspcct contr ibutc noth ing urrusrr : r l topote

t ia l appl icat ions.

Mcchanical Properties' I 'he

regular typcs o[ I r .V.C. f ibre I rave r uscfu l cor lb in l t ior r o l' 455

LX Cont i r ruous Fi laruerr t


tenac i ty an( l e longat ion , we l l su i tc ( l to genera l tex t i l c app l i c r t ions .' l ' he rnechan ica l p roper t ies a re unaf fec ted l ; y l l to is tu re .

Fabrics madc front P.V.C. fibrcs have atl atlractive handlc,aod arc \vlrnl and co|uforl irble against the skin. Thcy havc ah igh abras ion rcs is la t rce and good wcar ing qur l i t ies ,

Spacific G ravity

The specil ic gravity of 1.4 is fairly high, in the same rcgion asthc modacrylics.

Moist ure Reluiottshi ps

P.V.C. Iibres are absolutely non-absorbent, and the fibres donot swcll in water. The ntechanical propertics of the l lbre areunaflccled, and fabrics nrade from P.V,C, are dirnensionallystrblc ;rnd crcasc rcsisllnt rvhcn subjcctcd to ny form o[ wctprocessing. I ' .V.C. fabrics wash and dry casily and quickly.

Thcnnal Propertics

P.V.C. fibres havc exccllelt t lrermal insulation propcrties, andthis contributes to the warmth of properly-constructed P.V.C.ganlrcnls. The good low-tcr perature properties are an advantagein ccr ta in app l i ca t ions .

Thc low softening terlrperaturc of P.V.C. Iibre, on the otherhand, has always been a drawback to its use as a gencral purposelexti le nbrc. Thc introduction of the newer types of l,.V.C. fibrcspun fronr stan(lar(l an(l chlorinated P.V.C. rvith increased heatres is tance, has inc reasec l the versa t i l i t y o f the f ib re .'fhe

high dcgrec of strctch that" may be locked into P.V.C.fibrcs by slretcbing when warm, and subsequcntly.cooling,bestows upolr these fibrcs the high bulking charactc/stics thathavc bcen so useful in acrylics.

P.V.C. l ibrcs are absolutely l laneproof, and this has provedone of their nlost in'rportant features. Mixed rvith otber fibres,they wil l suppress the flarnrnabil ity of thcse fibrcs to a rentarkablcdcgree; 25 pcr cent ol P.V.C. fibrc blcndcd witl cotton or otherccllulosic Iibrc, for exanrplc, wil l prcvent the fabric or yarn fromsuppor t ing combust ion when ign i ted i 75 per cent o f P .V.C.llbre in a blend of this sort wil l rencler the ntixture alnrostnon- f la rnnrab le .

4s6

T----lL

- - L ' 1 t l t l ' [ ' I I

R * 457

ft

l l : s Y N . t - e r I C F I n n E s

l)rviron rn c nt ul C onl i t i onsJ ' .V .C. f ib rcs l ravc un cxcc l l cn t rcs is t iu lcc lo t l rc <Jcgr . ; r t l i r l i vcin0ucr )ces encountc rcd in ou ldoor r rpp l i cu t io r rs , in . t , , , f ing lu , i i i g l i iinsects and nlicro-organistns.

Chemicul Rcsista cc- l

hc h ig l r rcs is lancc o f p .V .C. l ib rcs to c l rcnr ica ls , inc l r r t l i ns ac i r l slund alkalis, ntakes thcse l lbrcs lhc l irst clloicc for rrlrny ;,,r '"n,rfri, i iapplications.

- fhc poor rcs is tancc lo cc r ta in comnton so lvcn ts , on t i rc o t l rc r

hand, has created problcrrrs in ccrtain texti lc applicrtions. p.VCgoods cannot be dry c lcancd w i th t r i ch lo roc thv lcnc l r r t l c r rcr rus t t l re rc fo re be t rkcn in d ry c lc rn ing to ensure i l ra t thc cor rcc tso tvents a re used.

Elccr ricity

[ ' .V .C. . f ib rcs

gcncr f l t c ncg t i vc c lcc l r i c i l y by t r i c t io

w i t l r thcsK l l . w l rc rcas t r )os l o t l l c r f ib rcs dcvc lop l los i l i vc c lcc t r i c c l | i t rpcs .I t i s c l : r i r r red r l r l t t l r i s ncg . r l i vc c tcc l r i c i t y t , , , . r f , " r " | ' r " i i r i " - " i i t? . r r .and is o[ valuc in thc trcatnrcnt of ihcunratisrn ",,A ,i,, i i i , , icomplal'uts.

Whcn P.V.C. l ib rc i s b lcndcd w i th woo l thc ; :os i t i vc c lcc t r i c i t vgcncra tcc l on lhc woo l ncu t ra l i zcs thc r rcgat ivc c lcc t r i c i t y on i t rcP.V.C,, so that static is reduccd or clinrirratccl.

. . In - t r . l91ds

_wi t l r co t ton or r ryon , thc c lcc l r i c i l y gcncr l t cd bylhc .P.V.C. f ib res is c l i ss ip : r tcd by thc cc l l r r los i i ib rc . Nv lo , i .acrylic, acctatc or silk f ibrcs do not dissipttc ttrc ctrrrgc io'a,iys ign i l i can t cx tcn t .

, l I s ta t i c

^c lcc t r i c i l y i s car rs ing t roub lc i r r t l r c p ro :css ing or r rscor l ' . v .U. - t r0 rcs , i t l l ay bc prcvcu tcd by us i r rg a r r lppropr . i r r t can l i s ta t i c l in ish .

\YnshiDg

Fabrics containing P.V.C. fibrcs nray bc wrshcd crsity arrtlcffcctively, so long as care is takcn to cnsure thnt lukcwflnn watcronly is uscd. 'fhe

water tcmpcralurc ntust not bc highcr than600C ar rd p re fe rab ly be t rvccn 30 and 40oC.

, - t lU

I I N D E O O K O F T E X T I L E F I A R E S

DryingP.V.C. fibre does not absorb water, and fabrics dry quickly andcasily. Moderate temperatures only (below 65"C.) should beused.

IroDing

Fabrics made frorn 100 per cent P.V.C. fibre, or from blendscontaining a high proportion of this fibre, are dimensionallvstable and wrinkle resistant. They do not usually need ironing,but if it is considered necessary a cool iron should be used. witha damp linen cloth between irorr and fabr.ic.

Fabrics made from blcnds containing 25 per cent or less ofP.V.C. nbre may bo ironed usually without dill iculty, using a lowtemperature setting.

Dry Cleaning

Fabrics containing P.V.C. tibres may be dry cleaned rvith petrol(gasol i r re) or rvh i te sp i r i t , but benzene ancl t r ich lore thv le r reshoulc l be rvo ided. Perchlo roe t hy lene shoul t l be uscd caut ious ly .

End-Uscs

f ib rcs can be used i r r n rany app l ica t ions . The rna in uses fo rPou lenc Tex t i le P .V.C. f ib r ; i a re hos ie ry a r rd [u rn ish ing

P.V.C.Rhonefab rics.

I ndust rial A p plicat ionsThe chemical resistance and non-flammability of p.V.C. fibreshave enabled them to find important uses in tho industrial field.Typical applications include:

Waddings, Iiltcr cloths, braiding, piping and other uses in thechemioal industry;

Brtlery fabrics:Protective clothing;Tarpaulins, awnings, curtains, lishing nots, etc.;Fairings and canvas awnings for aircraft, gliclcrs, boats,

DUOyS, elc.;Orthopacdic materials, artificial limbs, saddlery, etc.;Accessories for textile macbinery, bill iard cloths.

458

r

B : S Y N T I I E T I C F I N R E S

Filtration. One oI the nrost irrrDorlant of rhcsc iDdustrial uscs isIn thc I l t t ra t ton o[ corros ive l iqu ids, inc luding st rong ac i t ls , n lka l isand oxtd lz lng agcnls . I r torgal r ic c l rcnr ica ls , as a gcncra l r r r lc , donot attack P.V.C. fibrcs, but. carc must. bc lakcri to ",,sur" th"torganic naterials do not swcll thc librcs.

. In the filtration of gascs, thc humirJity of thc grs docs uotinlluence the pore size of the fabric. Als'o, thc accinrLrlation oistatic €lectricity by the fibres may hclp in tiltration by rrtractingparticles of dust and dirt to tbe filtcr fabric., Controlled shlinkage ol the filtcr fabric nray bc used to crcllcfabrics capable of filtering ultra-fine particlcs irom liqui<l nrcclia., P.V.C. libres may be used in thc form of lintcrs, rva<l<ling orflock, in addition to the nornral fabric fornr.

The choice of fabric to bc used dcpcncls upon thc tcnlpcraturcof the material to be filtered. If the tempcrature is bclow about70oC., . f t rbr ics nrade f rorr r rcgrr l : r r l ) .V.C. f ibre ( .1 ; ibr rvy l '1 rn ly bcuse(1. n t tcn lPera(urcs abovc t l t is , l t is l ) rc lcr i l l ) lc to l tsc: t l lcut -stabilized type of P.V.C. such as .'l 'herntovyl'.

U p holstery ; F urnis hi ngsThe resistance of P.V.C. fibres to dctcrioration has brought manyapplicaiions in upholstery and furnisbing, cspccially ii tropicr-lcountries. Mosquito nctting, furnishing fabrics, awnings, tcnts,etc., are not afiected by noulds even undcr t.hc most humidconditions. The resistance to insects and othcr aninral pcsts isconrplete.

, Thcse sams propcrties, allied cspccially with thc non-flammability of P.V.C., have opencd up inrportant ficlcls oIapplication in the furnishing of cincnrai, thcatrcs, ships andaircraft. P.V.C. libres provide fabrics for curtains, nwnings,upholstery, carpets, netting, hammocks and the likc. p.V.C.waddings and fclls are used as non-flanrmablc insulationmaterials.

The motor car trade is an important outlct for I,.V.C. fabrics.providing hoods, seat covcrirrgs and othcr filbrics.

The largo varicty of cloquc, knop and other clTccts which arcobtaincd by using thc thcrnral shrinkage of p.V.C. fibrcs nrovidesnovelty c{Tccts for furnishing fabrics, which rnay bc obtaincclsimply and cheaply.

459

I I A N D A O O K O F T E X T I L E F I B I I , E S

A ppat cI

The sensitivity oI P.V.C. fibres lo heat has tencled Lo restrict theiruse in the l ield of apparel fabrics. Unstabil izcd P.V.C. l ibres beginto shrink at tcmperatures which may be as low as 70'C., andgrcat carc rnust bc excrciscd in the washing and ironing offabrics containing thcse fibres. Also, the fact that certain com-nonly-used dry cleaning agents wil l soften P.V.C. l lbrcs hasprovcd a drawback to their use in clothing applications.

'fhe dcvelopmcnt of thc ncwer typcs of P.V.C. fibre (see page447) has greatly improved the prospects of P.V.C.0bres in thishcld.

Despito the ditl icult ies inherent in P.V.C. fibrcs, they have madeconsiderable progress in some apparel applications. P.V.C. fabricshave an allractive handlc, aucl arc very plcasant to wcar next tothc skin. Uscd alone or in blends with othcr f lbres, P.V.C. fibresarc used for hosiery, sports and travcl shirts, and baby clothes.These garnlents may be washcd easily in lukewa[m water, dricdovernight, and used again without ironiog.

Spccial cfl-ects are obtained by making usc of thc shrinkagc ofP.V.C. when boiled in water. Cloque fabrics, Ior cxample, arcmade by weaving alternate bands of P.V.C. with other yarns,followed by heat treatment which brings about shrinkagc of theP.V.C.

The use of a P.V.C. weft and a warp of a dil lcrent nbreprovides a fabric which may bc weft-shrunk to produce a tightly-packccl warp. Vclvets of great pilc dcnsity, for cxanrplc, nray bemade by using this technique. Wrtcr-resisting lapiics, l ikcwisc,may bc nradc lor use in rainwear, sports iackets, riniforms, ctc,

Bletrds with Wool

P.V.C. staple l ibre is blendcd wilh wool for the production ofwoollcn goods, providing fabrics of incrcased strength. Thcmill ing capacity is incrcascd by shrinkage at clcvatcd temperature,yielding a cloth which would not otherwise fclt. Shrinkagecapacity is l ikewise added to labrics which are normally incapabled being milled.

In worsted goods, the addition of P.V.C. fibres brings aboutan incrcasc in strength, and nrakcs possible lhe produclion ofbouclC clTects.

The addition oi P.V.C. to wool is also a way of lowering the

460

T ' *1 - - l - - l , - . ' l - l . l . I n | . I

461

' D Y N E L ,

f tI

B : S Y N I I I E ' I t C F I r ] I I E S

cos t o I a fabr ic w i lhout dc t rac l ing s ign i l i c lu t l y f rou thcchilrncteristic propcrlics of wool, lntl at , i," ,.,,t" 'r i,,,"",,.f,f i ,,"lesirable_propcrtics, such as non-namnralriliiy, wi;;il;;ili;;;,:rhc P.V.C.

Blaruls with Co o tl l lqolP.V.C. fibrcs arc blcndcd wilh cotton lntl othcr ccllulosic fibrcsto- b l ing about incrcasc in s l rcngt l ) , i r ld ro , , , " t . pu. r r iL t "

" i t , "

c l lcc ls obt l inablc f ronr contro l lcd shr inkrrgc, "c . l r " i , . i j . .1 i " . , . .l 'he tandlc, war'rtlr anl crcrsc_rcsist'ncc"of ;;;";' i;,;r;: ';; ':tncrcased.

Illcntls vith N ylon

P V,C. f ibrc h lc ldcr l rv j th r ry lor r prov ic les a fu t r r ic i r r which l l l lvo l . . t t1c essc i r t ia l char lc ter is t ics o l thc ny lurr * ru . t , . i - iu i ' " i i i fr r r i l t lerv rcs is tance - i l rc rc ta i t rcd.

(2) VI NYL CI I LOtr I DE COI,Ot ._yt t t l i t { l l l t } t { l ts

Fjbres.spun -fronr copolymcrs of vinyl chtor.idc rvith u sntlllcr.proPort ioD of a sccorrd Inonontct .

-The f ibre 'V inyon'HH, for exanrp le, is sprrn f ronr I co l to l l ,n tcrof v iny l ch lor ic lc arx l v iny l accta lc , whic i r conr l , i r rs Sj ' to ' t i rspcr ccnt of v iny l ch lor idc by wcight .

CI ' l r - CHCI 1-

VINYL CIILORIDE

c f i , =cHocoot r -> -cHr - iH-o !_ fH_

VINYL ACETA]E

' f l r c l ib rc . 'Dync l ' - i s spu t r f ro r r a copo lynrc r o I v i r ry l c l t lo r i t l c

ano acry lon l t f l l c , wh ich arc i r r thc r l ( in o f 60 l l i t r t s to .10 p l l r t sby wc igh t respec t ive ly . (p roduc t ion suspcn( lc ( l ) .

CHz -Cllct + Cftr= C|.|CN -> -c l t : - c f t -c l t r_ f l t_

c L c NV I N Y L C I I L O R I D E A C R Y L O N I T R I L E

CL OCOCHT'vrNyoN, l t

I -== [F t t l ' l l . , l t l . i F l f . ' i 1 .1 F , i F . l_ f iFJJI I A N D D O O K O F T E X T I L E F I A R E S

IN'II{ODUCTION

Difticulties experienced in spinnilg 100 per cent polyvinylchloride during the early 1930s lcd to many attempts to increasethe solubil ity of the polymer. One technique was to introduce asmall proporlion of another monomer into the polymerization,to fortl.I a copolymer wlrich would be expected to have increasedsolubil ity.

In 1933, Carbide and Carbon Chemicals in the U.S. dcvelopeda copolymcr of vinyl chloride which was capable of beingclissolved iu a solyent and dry spun into l ibres of useful properties.' lhess

fibres wcrc given thc name'Vinyon'.Commcrcial developmcnt of 'Vinyon' ftbrcs did not ttkc placc

until 1938, whcn American Viscose Corporation began producingthe l ibres for the first t ime.

'Vinyon' was markoted originally as a continuous l l lamentyarn,'Vipyon'CF. Production of this has sincc bcen disconlinucd,and'Vinyon'is now available as a staplc fibrc, 'Vinyon' I{H.

Today, a number of f ibres are spun from copolymers in whichvinyl chloride lorms the major component.

NOM ENCLATURE

Tlre system of classification used in the Hantlbook ol Texti leFibres is based on the chemical constitution of the fibre, thepolyncric unit which is present in greatest proportion beingregarded as the chemical type of the l ibre. Using this system ofclassil ication, all copolymer fibrcs in which vinyl chlrride provides

the major proportion of polymeric units are included under theheading of Potyvinyl Chloride Fibres. Thus, any copolymer madcfrom two iironomers, of rvhich vinyl chloride forn)s more than50 per cent by weight, is regarded as a polyvinyl chloride fibre.

F'cderol Trade Conunissiott De linitions-fhe

dcfinit ions rdopted by the U.S. Fccleral Trade Commissiondo not, unfortunatcly, follow a straightforward chemical systemof classification. This leads to some confusion, for example, inthe consideration of vinyl chloride copolynters.

According to the F.T.C. delinit ion, vinyl chloride copolymersin which vinyl chloridc forms at lcrsl 85 pcr ccnt by wcight nrcknown as virryorr f ibrcs. Tltc tcrm moducrll ic, on thc othcr hltrd.

462

D : S Y N T I I E T I C T I B R E S

is used for thosc fibrcs in which thc polynrcr is conrposcd o[lcss than 85'per ccnt and at lcast 35 pcr'ccrrt , i ""ri l" ir i ir i [.Ih" l i , f ib l : bascd or a polyrncr coutaining, sry, 60 p", "" , i i 'o i]llYt,.!ftonctc unirs aud^.40 prr cenr oI acrylonitrilc irlits is byuctrl ltron a rrrodilcrylic f jt)rc. Its nnnlc irssociltcs it with ircrvlorri-t r i l c , . whcrcas_thc bu lk o f rhc po lynrc r i s po lyv iny l f i , f " * i r .

" '

r lb rcs ln th ts ca tcgory havc bccomc o [ cor r r0 tc rc ia l j r r rDor t l r rcc .and are propcrly considcrcd as fibrcs of rh" polyvinyl'chiorit l.:typc.

As in the case of any fibres bascd on copolyntcrs, thc propcrlicsvary grcatly, cvcn thougll the n)il jor contpot)cDL is l l tc sarrre.,,t) , l l"

.q"".t lon whiclr follows, two fibrcs arc takcn as cx nrplcs

oI vlnyl chloflde copolymcrs:

. (a ) 'V inyon '

I - lH , wh ich conta ins morc th rn g5 pcr ccn t v iny lchloridc, and thus comcs rrnclcr rhc f-.-f..C. ,icn"irii,i il ri,,l"l,',an(l

(b) 'Dyncl', rvhich contains 60 pcrcomes under the F.T.C. dcfinition o[minor componcnt is acrylonitrile inploportioo.

(a) ,VINYON' HH

ilxil,"J.; ti ii,l,.'..',a,?i,l|: 0tiii",1',,"llj;li ti" lfi ""J,:i"Jl,,:;of vinyt,chtoride (8s-86.s per ccnr) ,,r,i ,i,yi ;;;i;i;?i;"jii:iPer cent) .

By F.T.C. dcfinition, ,Vinyon' HI{ is a virryorr fibre.

PRODUCTION

cc l l t v iny l ch lo r i t l c , nndtttodacrylic bccarrsc thc

morc than 35 pcr cct|t

Mononrcr Synthcsis

(l) Vinyl Chloride, sce prgc 447 .

(2) Vinyl Acetate

Vintl acetlte is produccd by thc rcaction of acctylenc with acctica c i d :

cl{=ct-I -f cI{3cooH-+cH, = ct{ococl I,463

I I N D B O O K O F T E X I I L E F I I ] R E S

Thc rcaction nray bc carried out in onc of trvo w:rys:

(a) acetylcnc is rcacted with l iquid acetic acid at temperaturesup to 100'C., using mcrcuric salts as catalyst. Ethylidene diacctateis produced as a byproduct:

cFr =ct,t + 2 CH"COOH+(CHTCOO),Cr{cH.

This is pyrolyzcd to split i t into vinyl acetate and acclic acid.(b) Acctylene is bubblcd through acetic acicl to provide a

nrixturc of the two reactants in vapour fornt. ' I-he gas mixtureis passed over a zinc or cadrriun salt catalyst at 200_250.C.

Polynlcriza(ion

Vinyl chloridc and vinyl acctate alc copolyntcrizcd by enrulsionpolymerization or in a solvent for thj copolynrer, t lr. pro..ribe i r rg s i rn i la r to th r t used in n rak ing po tyv i r i yL 'cLr lo i i c ie (J ; ; ; ; ;448 )

' Ihe polynrer izar ior is conr irr iccl " , , t i t 'o

prfv, i i . , o i , i ,6 i . i " -ular rvciglr t in thc rangc 12,000 to ZZ,0OO ir .s 'Uceu

-rco" i i " , i .

Spirrning

Thc polymcr is dissolvctl in acelonc, ancl the solution is thcnIi ltcrcd, de-aeralcd ancl storcd in hcated tanks. Front the storacetank , lhc so lu l ion js purnpcd to t l te sp iuncrc t . As lhe f inc ie tserncrge [ rom thc sp in lc rc t bo lcs , thcy fa l l th roug l t / r sp inn lnctubc t l ) roug l t wh ich ho t a i r i s pass ing . Thc ace tonJ is ' "uoporn t "Jto lcavc-solid fi lantents of vinyl chloridc/vinyl acctate .opbly."r.

The nlanlcnts produccd in l lr is way are brought togeihei intoa low which is rvound or to a spiudle. Thc early types of'V inyon ' ,

c .g . 'V inyon ' CF, were s t rc lched a f te r sp inn ing in

or ( te r to oncn ln lc thc n to lec l t l cs l rnd inc reasc thc s t rcngth o fthc fibre. lvlodcrn 'Virryon' I-l l" l is scl<lom rrsc<l in applic-ationsrequiring grcat tcnsils strcngth, howevcr, and it is oioclucetl inl l l c r rns l rc lc l l cd fo ] l .- fhe

tow is lubr ica ted and cu t in to s tap lc .No lc . T i tun iL rn t d iox idc n ray bc n t i xcc l in to lhc sp inn ing so lu t ionlo p roducc a du l l yarn , a r rd co lour .cd p ignrcn ts n t i i y bc in t roc luccc lto p rov idc a so lu l ion-dycd or spun-dyed yarn .

464

r I" - t r l r - l - - [ . . 1 . J

465

r f r - l r-t

r ] : s y N ] t t c t l c r l t R E SPROCISStNC-

lrJcrng

Disperse dyes arc uscd in con junc l jon w i t l tl s

-d r ,bu ty l ph t l ) i r l l t c o r o_hydroxyc l iphcr ry l .

sno td no t excccd 55 .C.

SII{UCTUIiE AND pl{OpEt{l . I I :s

Ir inc S(ruc(urc :rnd ppclrrncc

Srnooth sur f rced f ibrcs o l . round or dog_l tonc cross-scc l io l t .'l'cnacily

6 .2-8.8 cN/ tcx (0.?* I .0 g/ ( lcn) , wcr or ( l ry'I 'cnsi lc

Strerrgt l l

840- I ,190 kg/c l r2 (12,000_l?,000 lb / in2.1.

I loDgtl ion

100-125 pcr ccnl, wct or dry.

Spcci l ic Crnvi ly

1 .33- I .35.

Ellcc( of l l toisturc'V i r ryon ' l {H

absorbs vcry l i t t l c n ro is tu rc . l tU . l pc r ccn t . I t docs no t swc l l in w i l l c r , f lnd t l l crcntain unallcctcd by watcr.

'l hcrDlirl ltroltcrtics'V inyon 'so f lcns

a t 52 .C. and s l rnnks o !a t 85 'C. and nrc l ts a t I35 .C.

Flanrnohil ity. Chars, but wil l not brrrn.

l i l tcct of Agc

Ncg l ig ib lc .

s rvc l l ing l rgcn ts s r rc l rI )ycb i t lh tc r ) )pc l . i t lu rc

hi ls i t rcgit in ol-tcnsi lc prol.rcrt ics

I t bccor r rcs s t i cky


tif lcc( of Surl iSha

Ncgligiblc.

Chctnicrl Propert ies

Ackls

Unaflectcd at normal tempcratures by mincral acids. Hot acids

cause deconrposit ion and embrit t lement.

Alkalis

Unaflected by 30 per cent caustic soda or caustic potash.

uenetar

Coocl resistancc to nlost comulon chemicals, including perspira-

t ron ,

'Vin!o!t 'HII

466

30 60 90 120STRATN (% ELoNcATTON)

trJJJJJ-F. F. N F. T F, F F, F FB : S Y N T I I E T I C F I I ] R E S

li l lcct of Orgarric Solrcnts

Ilcsists alcohols, pet.rol (gasolinc), para in antl nrincral oils. lt issoftened by aronratic hydrocarbons, cslcrs trrd cthcrs, Dissolvcsin ketones and to sorne cxlcnt in chlorinrtcd solvcnts.

loscc{s

Not attacked by moth grubs or bcctlcs.

Micro-orgaoisnts

Not at.tacked by rnoulds or bactcria.

It lcctrical Propcrtics

I{igh dielectric strcngth o[ 650 volts pcr nri l nt 60 cyclcs.

Allcrgcnic Propc(tics

Not toxic to skin surfaccs.

.V INYON' HH IN USE

Ccncral Cllarnclcristics

The low softcning [emperature of'Vinyon' Hll, quitc apart fronlany other factor, denies it anything but very spccializcd tcxtllcapplical.ions. This being so, there is littlc jnducemcnt for lhcnranufacturcr to improvc tcnsilc and clongation propcrlics inorder to make the fibre more suitablc lor nornral proccssing tcclr.niques. In this conncction, it is interesting to notc that lhc tcnacityof the ear l ier V inyon' CF rvas in lhc region o l '30 cN/ tcx ( :1 .4g/den), and tlre clongation l8 per ccnt, so that it rvoultl trcpossible to effect consitlcrable inrrrroverrrcIt iI rrrcchanicalproper t ies of 'V i r ryon ' t l l l i i thc nect l ihoukl r r isc.

The chemical and biological propcrtics of 'Vinyon' I.I[I nrcgeneral ly s i r r r i lar to those of 100 pcr ccnt i , .V.C. l " ibrcs. lhc[ibre is corrrpletely non-flarnrrral>le, alld is resistclt to ntanychemicals. lt is attackcd, horvcvcr, by a fairly rvitlc rangc ofcommon solvcnts.

Ind-UsesVinyon' l l l l is used as a bonding f ibrc in non-rvovcl appl ic : r t ions.Mixed wi th o lhcr f ibres i t becorncs iacky rv l rcr r l rcatcr l and bonr ls

467

I I N D B O O K O F ' T E X - t I L E I : I N R E S

Thc rcaction nray bc carried out in onc of trvo ways:

(a) acetylcne is rcactcd rvith l iquid acetic acid aI ten]peraturesup to 100'C., using mercuric salts as catalyst. Ethylidene diacetateis p roduced as a byproduc t :

cH=clI + 2 cH"cooFI+(cHscoo)!cI{ct{'

This is pyrolyzcd to split. i t into vinyl acctate and acctic acid.

(b) Acetylene is bubbled througb acetic acid to provide anrixture o[ the two reactants in vapour fornr.

' l-he gas mixtureis passed over a zinc or cadnrium salt catalyst at 200-250'C.

I'olynrcrizntion

Vinyl chloridc and vinyl acctate arc copolynrcrizcci by enrulsionpolymerization or irr a solvent lbr the copolynter, the processbe ing s i rn i la r to tha t used in mak ing po lyv iny l c l t lo r ide (see page,148 ).

' fhe polynlerization is continue(l unti l a polynrer of nrolec-

u la r wc ig l l t in thc range 12 ,000 to 27 ,000 has bccn rcachcd.

Sp in n ing

Thc po lymcr i s d isso lvcd in ace tonc , and the so lu t ion is thcnfi ltercd, dc-acrated irn(l stored in hcated tanks. Fronl the storagetank, the solution is pumpcd to the spinneret. As the l lne jetsernerge from thc spinneret holcs, thcy fall through fi spinninglubc t l ) roug l l wh ich ho l a i r i s pass i | lg , Thc acc tooe is ' cvaporn tedto leave solid fi lanrents of vinyl clrloridc/vinyl acctate copolymer.

Thc fi lanrents produced in this way are brought together inloa torv which is rvound on lo a spiudle. The early types of'V inyon ' , e .g . 'V inyon ' CF, were s l re tched a f te r sp inn ing inordcr to oricntltc thc nlolecules and incrcase thc strcngth ofthc l lb rc . l v lodcrn 'V inyou ' l l l { i s sc ldonr uscd in app l i ca l ionsrcquiring great tcnsile strcngth, howevcr, aucl i l is producetl inlhc uns t rc lchcd fo rn t .-lhc

tow is lubricated and cut into staplc.

No lc . T i ta r r iu rn d iox ide nray t rc rn ixcc l in to lhc sp inn ing so lu t ionto p roducc a du l l yarn , a l l c l co lourcd p ignrcn ts t r ]ay bc in l roduccdto prov idc a so lu l ion-dycd or spLr r r -dycd yarn .

464

rl-t r-T 11 --t .-T r-J -J ''l - r . I ' r ' t ' I - l --- [ ' - -Ed

s Y N I l | E I t C I r t U l ( [ s

PROCT:S.SINC

I)ycing

Disperse dyes arc uscd in conjunction with swcll ing lgcnts sttcllrrs di.bltyl phth:rlatc or.o-hydroxyrJiphcnyl. Dycbrrtl i tc.-nr1.,, j1;11111,:s l ro r r ld no t excccd 55 'C.

S]'I{UCTUI{E AND PITOPEIU'I[ iS

Il ' i rc Structure a d Appcrrancc

Sn loo th su r faced f i b res o l r ound o r dog_ t l onc c ross_scc t i o l l .

'l'cDncity

6.2-8.8 cN/ tcx (0.7-1.0 g/ ( len) , wct or ( l ry

I 'cnsi le SIrc| lgt lr

840- I ,190 kg/cru2 1t2,000-t7,000 lbi in2.y.

l i longulion

100-125 pcr ccnt , wct or dry.

Spcci l ic Cr: lvi ty

L l3-1.35.

Ellcct of Moisiurc'Vinyon' I ' lH absorbs vcry l itt lc ntoisture, Jt has I rcg:rirr ol-0 .1 pcr ccn l . l t docs no t swc l l in watc r , and lhc tcns i l c p r .6pcr l i csrcnlain unallcctcd by w tcr.

'l hcrlrll Itropcrtics'V inyon 'so f tcns

a t 52 'C. aod shr inks a [ 60 , 'C . I t bccor rcs s t i ckya t 85 'C. and nrc l ts a t I35 'C.

Flarntnohil ity. Chars, but rvil l not brrrn.

l i l fect of Agc

Ncg l ig ib lc .

46s

- t - t

: t NhTFTI IF -FTTTT}TI ' A N D A O O K O F T E X T I L [ , F I B R E S

Ii lTcct of Sunlight

Ncgligiblc.

ChcrDicrl Properlics

Acitls

Unallected at normal tcmperaturcs by mineral acids. Hot acidscause decomposition and embritt lement,

Alkalis

Una(ected by 30 per cent caustic soda or caustic potash.

General

Good resis[ance to n]ost common chemicals, including perspira-I lon .

'V inyon ' I tH

466

@@

?xp:'@Y tfll

\ig%̂

l

D : S Y N T I I E T I C F I I ] R E S

lil lcct of 0rgrtrric SolvcDts

llcsists alcohols, pctrol (gasolinc), parali in anrl rrri lcralso l tcnco by aror ) )a t i c l t ydroc t rbor rs , es tc rs a r rd c t l rc rs .in ketones and to sonte cxtcot in clt lorin;rlcd solvcnts.

Insecls

Not attackcd by nroth grubs or bcctlcs.

Micio-orgaDisnrs

Not attacked by rnoulds or brc(cria.

Illcclricrl Propc.tics

Il igh dielectric strcngth of 650 volts pcr nri l ut (r0 cyclcs.

Allcrgcnic Propcrtics

Not toxic to skin surfaccs.

.V INYON' HH IN USE

oi ls . l t isl)issolvcs

Gcncral Ch:lr:lclcrislics

Thc low sol ten ing tcmperature of ,V inyon' I . l l l , ( tn i tc i rnxr t f ronrany_.otber factor, denies it anything but very spccializcrJ tcxtilcapplications. This being so, rhcre is littlc j|lclucenrcrrt Ior thcnra.oufacturer to improvc lcnsilc and elongation prop"rti"s i,iorder to make the fibre more suitablc for nornral proccssing tcclr.n iques. In th is conncct ion, i t is in terest ing to notc ihr t thc tc ] rac i rvof , the ear l ier .V i r ryon ' CF was jn the

- regiorr o f :O . f . f lL"* i - i . ig i ( len) , and Ule c longat ion l8 per ccrr t , so t l r i t i l rvoul r l bcposslb le to e l lect cot )s i ( lcr rb le i r I lprovct l rer r t i t l r r rcc l r l ic l lproper t ies of 'V inyon' I l l j i f the necd i l rou l t l r r isc.

The chemical and biological properties of .Vinyon' I.l l.I rrcgenerally similar to those of 100 pcr cent i '.V.C. fjbrcs. ,l.hcf ibre is conrp lete ly non- f lanrnrable, ar rd is res is tant to nrar ivchemicals. .lt is altacked, horvcvcr, by a llirly rvirlc ralgc oi.common solvcnts,

End-Uscs

.Vinyon' . l l l l is used as a bondi r rg f ibrc jn non_rvovcrr : rpp l ic l r t ions.Mixed wi th othcr l ibres i t becor i rcs tacky rvhcrr hcatcr i ar rc l bont i i

467

I I N D I } O O K O F T E X T I L E F I B R E Sthc nmss of l ibres togct l rcr . I l . is t rsct l in t l r is rvav [or r r r : rk i r rpfc l ts , borrdcd f i rbr ics arr t l hcat-ser lab lc papcrs. l tnDo; t tn t rDDl icx:t ions- inc lude f i l ter fa [ : r ics, ter .bags. dooi prnel ; and webt ; ines.'V inyon' is used for in t lust r ia l ant l out t ioor fabr ics inc lut l i "nsgi t r t ler : furn i turc , tarpaul i r :s , rwnings, f i l ter c lo ths 3nd protcct ivEclo th ing.

(b) .DYNEL'

'Dyrre l ' rvas a f ibre of thc polyv i r ry l ch lor idc type produced bythe Fibcrs and Fabr ics Div i i io ; oaUnion Carbi i le bor forr t io , i ,i r r^ t l re U.S.A. I t was.spun l ronr a copolyr r rcr of v i r ry l 'ch lor ic le(6U per cent) ar )d acry loni t r i le (40 pcr cent) .

Ily F.'f .C. dcfinition,'Dyneli wis a notlicrylic fibre.I NTII,ODUCTION

Thc most ser ious d isadvantage to lhc use o [type fibrcs for general texti le applications l iestng point. Many attcmpts were nrade lo raiseoI. vinyl chloridc/vinyl acctatc copolyntcrs,'\ ' inyon'

I ' lH, by adjustnlenl of the relativctwo conrponcnls, but without succcss.

po lyv iny l ch lo r idcin thcir low soften-the soflcning pointas uscd i t r n lak ingproportions of thc

Dur i r rg . the work on v iny l ch lor idc copolynrcrs, Iowcvcr , i twas lound thst l lbres of sat is factory sof tcn iDg point could bcspun. from .copolymcrs of vinyl chloridc arrJ icrylorritrilc, iriwhrch the v iny l ch lor idc rcmaincd t l tc nra jor co rponcnt ..-.ln "lrll fibre produccd from copolymers of lhis type was'Vinyon' N. 1-h is wrs a cont inLrous f ihmcnt l ibrc *h1; i ; ; ;dry-spun l ror r a so lut ion o[ v iny l ch lor idc/acry loni t r i lc )copoly-n)er . I l is no longcr produccd.

In- 1951, Union Carbidc Corpora l ior r in t roc lucct l on to thctcx l i le m:r rket a ncw f ibre ca l led ,Dyncl ' . This f ibrc was s inr i larlo . 'V inyon' N in that i t was spun f rorr r a copolynre, of u inv ichtof lde and acry loni t r i le , wi th the v iny l ch lor ide forming themirjor componcnt. IJut it was wet-spun iristcad of bcing dry_lpun,and i t was avai lab le as s taple and tow, instead of

-coni inuoui

I r lamen t -

. Proc luct ion of 'Dyrre l ' was la ter d iscont inuecl , but in forn lat ionabout it has been retained for its historic artd fechnical value irrthc fo l lorv i r rg sect ion. 'Dyt re l ' was of inrpor l .ance , , , , , . * ru, r i .o f a f ibre spun conrnrerc ia l ly f rorn a copolyrner o l 'v iny l ch lor ideand acry loni t r i le .

468

' t

469

s l ' N T | l l ] T I c F t n R E s.TYPES

OF I I I I ]R I ]

'Dynel ' rvas n larketc( l as s taDle,.niriu o *ii. ffi;;l;ili',i,ij'l"low'trislrt' scnri{ull rrrtl rlull,

lncrc wcre thrcc )a in typcs of ,Dyl rc l , :

(l) Rcgulur. Stanclard gr.adc slaplc nd row (.ll,pc lti0).(2) Controlled l! igll-slu.inkart'" Titf:fi ti jlJ,il'ltfiifiilj,ti i,ii,,l;:iJl,i',1lJTi,::il

(3) Cupc.t ,Filrc. A spccirl f ibrc for c;rrpct rrsc, rvit lr lowcr

H*il?;.i'f, llii,"];1,fl::'1,,T:*il f"";r';";;-"';' " L',;'i;iPRODUCTION

l\'Ionorrrer SJnthcsic(a) Vinyl Chloridc. Scc prgc447.(b) Acrylonitritc. Scc t]f lgc 399.

I 'olyntcriz:rt io|r

I:l''iJ"i?'l; l'"%,i:,i*"';1,;i:i,11: "'". (40 pa rrs) n rc por v-Spinning

Ij: o":jt19, is. dissolvcd in ncerr

"",.diii,'i"";"'j ;:,,1":l Jlil):*,:""- "tit*.ili'1";iii"[xrr,c..warcr, r.nd sorid nr,,,ii",,o' Ji ;::1,:,T,':,:X"r*;il.ll,'t, lil;il':l;'r",nj[T;;; i;:,:,1;':l:;l r'oi "'ir ri'",i.i'.,'i;,r'i;;,'';;,1;;;;;;,:;;' ;;;"' :i ;;;l ljii:']fi fffJ f :1"'; J,':l ̂::,1 H' ;i"il?:iPROCESSINC

I)csizirrg

D-csizing with cnzyn)c flgcnls is rcconrnrcndccl, cspccil l ly irr blcrrtlso f 'Dync l " ,v i r I cc l l r r los t f ib rcs .

ft1 n R n n n t I F F F F f: |', t,E-]'r_t_-h TI I A N D D O O K O F T E X T I L E F I B R E S

o

-.r -.l ul,,r

:E ? !Et t

v p i3 \ |" < \ I: l---J9 t z I

s < Ar,rx rr: ( ve4.

(,ztf

u4I

F '

TF

F

=

F

d

LoJ

_6

o

J

z

4'10


Scouring

Goods which havc bccn soilcd during proccssing may bc scourcclby t reatment- for up to I hour at 70"C. in a bath conta in ingnon-ionic surfacc active agcnt.

Illcachirrg'Dynel'is a white nbre which does not normally necd blenching.If bleaching should be considercd necessary,- sodiunt chloriicnray be used in a liquor acidificd with nitrii acid.

Dyeing

(a) 100 per ce l 'Dynel

'Dynel'-f ibre, stock, tow, yarn or picce goods may bc <.lycrl

ellectlvely by conventional methods, on convcntional equipmcnl.A full rangc of.colours nray bc obtaincd, from lights tirroughdarks, with cxccllcnt laslrlcss to pcrspirflt ion, crock-ing, wnshiigand Iight, and rcsistance to gas fading.

Dycstufls usccl include thc cntirc rangc of dispcrsc dycs, ncutrl lpremctall ized dyes, most of thc cationic dyci, ancl cc.inin vnidyes._ From this wide range it is possible to sclcct dycstulTs tomatch any rcquiremcnt, and to withstand virtually cvciv tvpc otscrvice required of thc finishecl fabric.'Dynel'may be dyed at temperatures bclow thc boil by usirrga carrier. This adds to dyeing costs, however, ancl subitanti lJquantit ies of 'Dynel'are dyed at temperaturcs of 96.C. and abovcwithout a- carrier. At tcmperatures of 96"C. with a carricr, thc ,f ibre's moisture absorption becomes high enough to bc of practicalvalue in dyeing. When the colour has been fixed in thc fibrc bvthe dyeing process, it is unavailable to the action of wrtcr nnithe various chemical agents that might be expectcd to dischargcor alter the colour. This results in cxccllent fast.nsss propcrtic-.s.

Restoritry Lustre'Dynel' absorbs watcr at dycing lcmpcraturcs, and this rnav bclrappcd in thc bot f ibrc, c:rusing a loss oI lrrstrc. l.his has asignincant eflect on the shadc attained. As l ight fastlcss ismarkedly better on lustrous than on dull f ibre, if is csscntial tobring the.dyed matcrial up to its fult colour value by restoringlustre. This may be dono by application of dry hcat'at l2l"C]

471

I I N D B O O K O F T E X ' T I L E F I I } R E S

by scnr i-decat izing with stcanr for shorl cyclcs, or in thc ctsc ofpackagc dyc ing by us ing a boi l ing sodi r rnr su lphatc so lut iou.

') hernoplosticity'Dyncl' is a thcnnoplaslic fibre, and (his nrust bc considered inall processcs involving elevatcd temperaturcs, inclu<.ling dyeing..lt must be given special atrent.ion during piece <tyeingl Coolirigat the cDd of dyeing nlust be done very slowly to avoid settin!crcascs in . lhe fabr ic . T ig l r t ly wovcn fabr ics jn par t icu lar nrus iue grvcll thts care to ayoid crelsing.

(b) Blends

In addi t ion to 100 per cent appl icat ions, ,Dynel ' is user l in b lendswl r natura l and rna - rnadc f ibres, arr t l rnay be cornnrerc in l lvunio l - and cross. t lyed pr i r r ted in a rv i t le ranre of , t , r , f . , S i i i , i r i iprocerlures are usetl for dycirrg blcnds with rayon, rryon anrlf lcerate, . . rayon and wool , r : ro l ra i r , wool , cot ton, acr t l ic a t ) ( lpolyauriclc libres.


Fine S{ruclurc and Appearance

White (or spun-dyed) fibre. Cross-section of regularshrink typcs: irregular ribbou; carpet nbre: roun.l to

Tcuci lv- cN/tex

(g. /c len.)

Tcnsi lc Slrcngl lr

kg/cnr2(p.s . i . )

[, long4tiorr(pc r ccn t )

Regular Mglt-Shrink

18 -31 37(2.0*3 s) (4.2)

and highell iptical.

\Cdrpct

8 .8(1 .0 )

Sarrrc wc[ or dry

4,060 4,900(58,000) (70,000

30-42 t4-t7 90_t20Santc wct. or dfy

4'12

- lI

' l r II I ' r t [ ' l - ] . :-t ,J

B : S Y N ' T I I E T I C F I I } I T E S

Iillslic Ilccovcry(l)cr ccut)

Avcr:rgc Stillncssc l \ / t c x

(g./dett.)

Avcragc Touglncss

Spccilic Gravity

l . J

Prolonged exposure causcs sonrcfi bre darkens gradually.

CLcrnical I 'ropcr(ics

Acids

Exccllcnt rcsistancc to acids of all

Ellec( of Moisturc

Rcgain: 0 .4W tcr .has v i r tua l ly no c lTcct on t l rc nrcc l r n icr r l pro l )cr l ics of t l tcfibr,e. There is no shrinkagc or fclting ", t"",r,"rl,i,i., i l"f"*DO tng po tn t .

Ihcrmal Proper(ics

Rcgnlar f ibre: slrain releasc slarts at 120.C.; f ibrc trcconrcsmouldable in thc rangc 135-163"C. (dry hcar) "i l" fr"if i"g *"i"r.H-igh-shrink fibre: shrinks 30 per ccnt in loil ing ;i i ;; ;;; i127"C. in dry heat.Carpct l ibre: strain relcasc begins at 130"C.

Flotnmability'Dynel'wil l

burn if held iu a flanre, but it gocs out if thc l lanrc,.�.ryg]:t! it.wi ,nor supporr combusrion. li docs ""i .riit,l il."j,o I mot ten mate t ra l .

E[ec( of Sunlig[t

1009395

@ 2 %@ s'/,@ to'i1"

90.9( r0 .3)

0.58

218(24.7)

0.13

8 .8( 1 .0 )

0.60

loss of tcnsilc strcngth. 1'lrc

conccn lri l l ions.

473

I I A N D A O O K O F T E X T I L E F I A R E S

Alkalis

Exccllcnt rcsistance to atkalis of all concentrations.

Certeral

l:! ",f:"1.,t by strong dcrergcnrs, soaps, ctc. Rcsistaat to a widcrangc ol Inorganic chcnticals-

Ellcct of OrgaDic SolvctrtsUnaficctcd by hydrocarbons, dry_cleaning solvents and nrostothcr organic solvents. Acetone, cycloheianone u"A'.i inr",f,"iformamide are solvents in varyinj d;sr;;.6;;i;i; i i,"lt ' l","lJjand somc a''.'ines exert ,otu"nt o.* .*"tti.,g';;;;,;,;;;il;;temperatures.

Insects

Conrplctely rcsistant.

?o 30 40(% ELoNGATToN)

'Dy el'

474

B : S Y N T I I E T I C F I B R E SI\{icro.orgalisnrs

Completely rcsistant.

Dleclrical properaies

Die.lectric conslant; 4.g6 at 60 cyclcs; 4.29 at 1,000 cyclcs. l_owmorsture absorption encourages accumulltion "f r,"ii","i".i,i i i irl

.DYNEL' IN USE

General Cbaractcristics

***ttg1$ffi''i"'ffi ' ̂ ;uo i:I i?i:

;flpifrg]h5[ilffit'"ffiMechanical properties

;1;fr$i'"',,qffi **+r;t*ifr ;t$i;#;frf$,'ffiil;;frti''ffirffiifi,;d,iil"$-.T",l:d,l.,ifi,jffi *itm*tlry;*n$:ili'*le-;:',l'4*fl ffi \,#i*

475

T I A N D D O O K O F T E X T I L E F I A R E S

Dinrc sio al Stabil ity'Dync l ' f ib re i s no t a h igh ly c rys la l l ine matc r ia l and i t docs no t ,therefore, have a sharp melting point. Whcn heated, the l ' ibre wil lshrink slightly as it reaches a strain-rclcase tentpcrature. l[ thetenrpcralurc is incrcased furtl ')cr, a grcatcr shrinkagc wil l occurunti l f inally all the strains imparted to the fibre have becu relieved.

Whcn a'Dynel'f ibre has had strains rclicvcd at a given tent-perature and time, it bccomes dimcnsionally stable thereafter upto this temperature for that t ime. Fibres held under tensionmay be heated considerably above their strain release tempera-turcs with only minor changes in molecular structurc. When'Dynel'fabrics are stabil ized by dycing at the boil, or by boil ingo[[, they are dimensionally stable in boil ing water and dry-heattenpcraturcs up to 120'C.

If 'Dynel' is heated in air at high tempcmtures, it darkensgradually and loses weight. lts nrechanical properties, however,arc prescrved to a remarkable degree. When 'Dynel' is heatedfor prolonged periods under tension, the tenacity at elevatedtcmperatures increases.

In order to take full advaotagc of thc dinrensional stabil ity of'Dynel' in blendcd fabrics for apparcl, it is prcferable for thcIoom rvidth of the goods to be greater than the desired width ofthe finished fabric. Finishing, then, should include one stagcat rvhich the fabric is allowed to relax complctely, under heatand rro tcnsion, to its natural length and width.

Novcl Fabric Constructiotrs \The controllecl shrinkage of 'Dyncl' nray be used to obbinselective dif lcrences between parts of a fabric in which ,Dyndt'

is used in conjunction with other fibres. PLrckered and bouclCellects, for example, are obtained in this way.

Fabrics may be knit or woven and stabil ized by heat shrinkageto give extremely tight constructions. The selection of olhersynthetic and natural l ibres for blending extcnds the range ofnovel fabrics o[ this type.

Heut Sctting: Moulding

Thc application of hcilt to 'Dyncl' [abrics at tcn"rpcrflturcs irbovethcir strain-relcase tcntpcraturcs is uscd in thc inrparting ofpermanent pleals, and in moulding fabrics into desired shapes.

476

' t ' t i ' lI

477

' |

I I ' l n

l r "

A : S Y N ' T I I E T I C F I I ] R E S

Thcsc shapc<l ftbrics arc dintcnsionally stlblc, and rcrunin :;otunlcss the slupiug tcntpcriltLrrc is agnin cqtrall"j or "x.""dJ

-

.The use. of bolh.lhc shrirrkagc and tlrc t ircrnroplnstic propcrticr

o r -uync l .a re . we l l cxcn tp l i l i cd in thc n ror r ld ing o f h i l t s , w l l c rc

tnc l bnc rs shruDk or t lo a fo rn tc r i lud l l l c t r sc t in t l r i s sh pc .For rad io and h ig l r - f idc l i ry g r i l l cs a r rd rhc f i t c , h i r l r i cnruc f " -

trrrcs arc uscd to provitlc fabric sti lhcss arrtl r igii l i ty to tlrt,f inished article.

Fire Resistance'Dynel' wil l not supporl conrbustion,' l-hc fibrc rvil l btrrn if hclt li n con tac t w i th an opcn 0anrc , bu t i t s tops burn i r r ! , " f , "n - - r f i "l i l n re l s re rnovcd. l ;abr ics madc en t i rc ly o f .Dyuc l , pass t l t cASTM Test D626-41 for f larne-retardcd icxti lcs, Lut sou,c ,tv"_slulTs irnd finishes contributc lo nantnrabil ity, rnd fabrics stror'rl,. lbe testcd beforc clainrs are ntadc as to their f irc rcsisltrncc.

Outdoor Exposure'Dync l ' J ras ou ts t f lnd i t )g rcs is tancc to o l l t ( loo t cx l tos l l f c u ldcr n l ltypcs. of. conditions, Wtrcn 'Dyrrcl ' fabrics wcrc burictl irr soiianq nc to undcr L rop tca l coud i t ioDs o f 31"C. aDd gZ pcr cc r l trclative humidity, no dcterioration oI the cloth was tlctcctcriafter 6 months. Eight-ounce cotton duck disintcgrated "ourpf"r"lfin l0 d tys under the samc cond i l ions .

In othcr tests, such as thc mineral-bnsc-agar and frcc-hanlitr,:t cs ls , no fungus a l tack was obscrved. ,Dync l ' i s cqua l ly rcs is ian ito attack by insccts.

. After uncovered cxposures in Floricla for 250 sunJrotrrs{approximately 60 days) on yarns and tapes of low dcnicr l ibrcs,'Dynel' retained more tl)an 50 pcr ccnt of its originrl tcnaciryan(l clongatron.

Blertcls'Dynel', by itsclf, combincs nrany of thc chlracteristics of t lrctnore expensive nalural f ibres with a nunrbcr of ntan-maclcfcalures not availablc in any natural f ibrc.. In blends with wool, 'Dyncl' nrakes slrongcr fabrics lhat hold

their shape. and prcss. Wilh rayon, ,Dyncl' provitlcs t varicty oftexturcs with.-inlprovcd shape and prcss rctcnlion and Iongcruseful wcar l ife. In blcnds with cotton, ,Dyncl' hclps thc fab-rjc


to keep its loft, and thercfore its softness and warmtb, even afterlong use and repeated laundering. From 25 to 4Q per cent'Dyoel',stock blended, is generally most advantageous.

W:rsbing'Dyncl' l ibres are non-felt ing and non-shrinking. These properties,coupled lvith high rcsistance to chenrical attack and high wetstrcngth, make possible repcatcd laundcring cven with stroDgdetergents under vigorous conditions. Fabrics may be disinlectedwith sodium hypochlorite solutions without alfecting tensileproperties or handle.

'Dyuel' fabrics may be washed either by hand or by machine,tho lemperature of thc wasb water being as low as possible,preferably belorv 50"C. (lukewarm).

As with all textile fibres, nappal fabrics may pill if subjectcdto extreme agitation jn automatic 'home laundries'. With properfabric construction, howevcr, nappcd 'Dyucl' fabrics can bcwashed with confidence in automatic machines-

Drying

The low moisture regain makcs 'Dyncl' one of t l)e fastest dryingfibres, In certain constructions, r,atcr is beld mechanically, andthis may be rcmoved immediately by centrifuging. Heavy nappedfabrics that are whirl-dried and hung up at room temperatureswill dry with remarkable rapidity.

Drip drying is preferred if possible; tumble drying in honredricrs may cause sofle shrinkage. Drying temperatures shguldnot excced 60"C. \

Ironit|g

Wrinklcs are removed very easily from 'Dynel' fabrics by ironingat low temperatures. If the ironing temperatu_res are too high,thc'Dynel'nlay sti lTen and shrink. To preserve the beauty andluxurious hand of 'Dynel' fabrics, the following pressing andironing instructions must be closely observed.

Wben ironing all 'Dynel' fabrics, the lowest iron settitg anda dry cover clolh of cotton or other fabric sbould be used.lf no cover cloth is used, an iron witb a lowcr thao 'rayon'setting

is ncccssary. All 'Dynel' fabrics can bc steam-prcssed at rcducedprcssurcs, and wrinkles can be removed by jet steanring, but

418 479

B : S Y N T I . I E T I C F I B R g S

steam iroDs, manglcs, or hot-hcad prcsscs shoulcl not bc uscd.The resistancc of 'Dynel'-conlaining

fabrics to slrrinkrtc bvhcr t i s inc rcasc t l rn : r rked ly by s tock-b lcnd ing w i th n rorc -hce ircsislant.-f ibrcs. When 25-40 pcr ccDt .Dynct' js prcscnt, l l lcfrbric wil l be stabil izcd ancl wil l rctain crcascs sct by an iron.ln gcncra l , such fabr ics can be i roncd f l t l l l c , rayon 'sc ing orwith a steam iron.

Dry CIclrniDg

Fabrics of'Dynel'nray be dry clcaned cllcctivcly, bcing rcsislantto the solvents commonly uscd. As alwnys, clcvalcd lcnipcraturcsn)ust bc avoided.

Dnd Uscs

Pile Fahrics

Ono o [ t l l c n ros t succcss fu l ou t lc ts fo r ,Dync l , i s i r r lhc p ru l r rc -tion.of furl ikc pile fabrics. 'Dynel' provitlcs pilc lhrt is softand lustrous, yct stable to st.etching and shrinking. Fabrics nrrrdcf rom 100 per cent 'Dyne l ' and f rom ,Dync l ' in conrb ina t ionwi th 'Or lon 'and o thcr f ib res have provcd cx t rc rnc ly succcss fu l .

Sttits; Dresses, etc.Dresses, suits, skirts, slacks, jackets and rainwcar arc son.rc ofthe applications for 'Dynel', conrmonly in blcnds wilh othcrfibres. In blends with rayon and acetatc,2j-35 pcr ccnt of,Dyncl'markedly increases fabric wcar l ite, wi rout pil l ing. In blcndswith wool, up to 35 per ccnt,Dyncl' contributcs itrcngth andresrstance to wear and tear.

To wovcn goods generally,,Dync[' inrparts wannllr, washabil ity,good draping qualit ics, creasc rctctrl ion cvcn whcn wct, and rilong useful rvcar l i fe.

Uttdcrvear; K nitwcar, e!c.In knitted goods, 'Dyncl' jmparts rcsistancc to shrinkrcc ancls t rc lch ing , in rp rovcd rc lcn t ion o I lo f t , a , , v : r r r r r l r rx r r r io r rs lu rn t l .and resil icncc, Blcnds of 'Dyncl' with olhcr f ibrcs arc rrsctl irrnlen's, women's arrd chilclren's unclcrwoar, slccpwcar antl socks.

A blcnd o[ 25-50 pcr ccnt of ,Dyncl' wilh cotton h:rs nrovcclpar t i cu la r ly success fu l in th is f i c ld , the ,Dync l ' con t r ibu t ing i : rs t i r rg

I I A N D A O O K O F T E X T I L E F I B I T E S

softness, shape and size retention through many washings andlong wear.

-I 'be cotton contributcs high absorbcncy and assures

that garments stay comfortablc next to lhe skin.

Furrishitrg F abrics; Curlains, etc.'Dyncl's f lamc-rcsistance ltas provcd an important propcrl.y irrthe usc of the fibrc lor curtains and drapcries. 'Dyncl'drapcrics,

for exanrplc, are uscd on lhe luxury l incrs Unitcd S/o/eJ andADteice.

Corpets

The spccial grade of 'Dynel' produced as carpet l ibre has pro-pcrl. ies different from those of regular 'Dyncl'. These propertieshave been built into the nbre to make it particularly suitablefor carpet use. Carpets nrade from 'Dyncl' combine strengthand easc of nlaintenance characteristics rvith cxccllcnt soilrcsistance, high resil icncc, good appcarancc and rcsistancc tomoth and mildcw-

Blankcts

Blankels nrade lronr 'Dynel'are shrinkproof and mothproof, andwilt withstand repeated laundering and cleaning. They dry quicklyand retain their warnlth and handle over a long period of hardwcar. In this applicalion, again, f lamc rcsistance is an importantassct.

Industricrl Applicatiotrs \

Chernical resistance and flame resistancc arc important charac)tcristics in a fibre uscd for protcctive clothing, and'Dynel'excelsin both respects. It is used for shirts, trouscrs, unifomts and otherclothing worn by people exposed to corrosive chemicals.'Dynel' is used also in launtlry nets, I l l ter fabrics. paint rollersand overlays for boats and industrial equipment.

(3) CHET,TICALLY MODIFIED POLYVINYL CTILORIDEFIBRES

Fibrcs spun frorn polyvinyl chloridc (or a copolynrcr o[ vinylchloride) which has bccn subjected to chenrical modification.

' - f r I r It l l

480 481

l - t - - 1 - - 1 -

B : S Y N T I I E T I C I : I I I R [ , S

Many ntodificalions of polyvinyl chlorit lc hrvc bccrr nrndc orr: tn cxpc f l t cn ta l b ts is , bu t thc on ly cor r r r r tc rc i l r l l y - i r t lpor la r r tfroccss at thc prescnt t ime is chlorjnaiion. f. ifr,", "r" .n,,ir-i iuii i;.h

lo^ri3arcd. polyvin yl -chloric.t_o i ' l wtrich rhc.1,i";;,; ' ;"; i i ;;;;;

n i rvc occn Incrcascd f ro r r r 57 pcr ccn l lo as h ig l r as 79 l rc r cc t r i

INTITODUCTION

In . 1934, Gcrman workcrs d iscovcrcd th t r t tho so l l rb iL ry o fpolyvinyl chloridc could be incrcasccl by clrlorinatiorr of t l icpolymer. The introduction of additional "irt.r i".,r ioi""r,f", i" iothc. polynter Iorced thc Iong nrolecrrlcs "p"rr, "nofrf i,* '-*lu",, inlotccrrtes to pcnctrate ntorc casily bctwccn tl lcnl.. In 1936, chlorinated polyvinyl chlorirJc fibrcs wcre nrxrketcdIn Lrcrmnny undcr thc traclc narrrc o[ .Pc

Cc'. Thcy wclc snunf ronr i t cc tonc so lu t ions o f t l t c ch lo r in i r tc ( l po ly r r rc r . '

- 'Pc Cc' nlcltcd irt too low it tcmpcrllrrrc (bclorv lm.C.) f o bco{ rcal value as a tcxti lc f ibrc, bui it ha,l a rrurirbcrci ;; ir,;;cnrrlctclstrcs which scrvcd it rvcll in spccil l izcd applicarioirs.ln par t i cu la r , i t was non- f lanrmabtc .'I 'he produclion of ,pc Cc' f ibrc continucd in Gcrnrany unti la.nd. during Workl War l l. l t is pror.luccd irr East Ccrrrrl ly as' l ) i v iac id ' ,

and in the U.S.S. lL .

PRODUCTION

Molrorlct Syntllcsis

Vinyl chloridc. Sec pagc 447.

I'olyltcrizalion

Vinyl-.chloride is polymcrizccl in cmulsion as dcscribcd onpage 448.

Chlorirra(ionPolyvinyl chloridc is dissolvccl in tctrachlorocthanc to lornr an8 p:.- 9"rrt solution, and chlorinatcd by trcllnlcnt *irf, "fif.rii i irt 80-90'C. Attcr 24-36 hours, rhc'ctrtorin" "onr"iit oi' i i i"polymcr has incrcascd front 57 pcr ccnt to aboul 62,65 pcr cuit.

I I N D B O O K O F T E X T I L E F I B R E S

The hydrochloric acid produccd during the reaction, togetherwith excess chlorine, is removed under vacuum, and the polymermay be isolated either by precipitation with methanol or byspray-drying.

Spinning

Chlorinated P.V.C. is dissolvcd in acctone to form a 28 pcr centsolution. After nltration, this is pumped through a spinnerct,the .icts of solution emerging into a water bath' The acetonedissolves in the waler, leaving solid li laments of cblorinatedP.V.C. which aro stretched and dried.

The lilarnents are brought together into a tow which may becrinrped and cut into staple.

STIT.UCTURE AND PROPERTIES

Fine S(ruclure atrd Appcarance

Smooth-surfaced libre, of bean-shaped cross-section.

TeDacity

I 5 .9 - 17 .7 cN/ tex ( I .8 -2 .0 g /< len) , d ry o r wet .

Elongation

24-40 pcr ccnt, dry or wct.

Spccifc Gravity \1 .44 .

Eficct of Moisturc

Regain: 0.2 per cent. Moisture has virtually no efect onmcchanical propertics.

Thcmral Propcrlics

Chlorinated P.V.C. fibres shrink usually at about 70'C., andsoften at 100"C.

Flannnbil ity. Non-llammablc. Do not support combustion.

482 483

rI ] : S Y N T I I E T I C F I B R E S

DlTcct of Sunlightl0 per ccnt loss jn strcogth aflcr I yeart cxposurc.

Chenrictl I'ropcrlics

Cood resistance to rnost chemicil ls, including acids antl ulkrl is.

l i l lcct of Orgrnic Solvcnts

So lub le in n rc thy lenc ch lo r idc , bu ly l l cc t l l c , acc tonc , xy lc r )c ,o-otcll lorobenzcne-

Insecls

Not attacked.

Micro.organisms

Not attackcd.

Ilcctrical Propcr(ics

The fibre softens at too low a lempcraturc to bc of rcal valucas an electrical insulator,

CFILORINATED P.V.C. FIBtlE IN USE

Chlorinatsd P.V.C. fibrcs are of l imitcd valuc rs tcxtitc f ibr.cs.largcly as a result o[ their low softening point. Thcy havc tounja number of specialized uses, howcvcr, which dcrive rnainly fronrthe flame-rcsislance and resislancc to clrcmicals. They nrc uscd.for examplc, in flanlc-rcsislant clothing, protcctiv" "totti i ,* i, iindtrstry, tarpaulins, tents, f i l tcr fabrics ind thc l ike.

I I N D A O O K O F 1 ' E X T I L E F I A R E S

POI-YVINYLIDENE CI ILO I I IDE FI t ]RES

Fibrcs spun f rom polymcrs or copolymcrs of v iny l idene chlor idc:

CH2 - C CLz ->-

V INYL IDENE CHLORIDE

INT ITODUCTION

t t- - - cH , - c - cH , - c - cH , - - -

t l

POLYVINYLIDENE CHLORIDE

ln 1940, tho Dow Chcmical Co. of Anrcrica introduccd a ncwtypc o[ synlhetic f ibrc consistiug o[ l copolyntcr oI viuylidcncclrloride and vinyl chloride. It was givcn the generic nanle Jcralr.

Vinylidcnc chloridc, thc chicf cornponcnt of saran, . is a colour-Icss l iquid tlrat was nradc as long lrgo as 1838. In conrnron withother vinyl-typc unsaturated compounds, jt wil l polylrlerize toform an csscntially l inear polymcr capable of fonning fibrcs.Polyvinylidene chloride was examincd as a possible source ofuscful synthctic f ibres during thc carly 1930s. The lack of a suit-ablc solvent causcd spinning diff iculties, howcver, and thc polymer$'as scnsil ivc lo hcat.

'fhc introduction of saran by Dow Chemical Co. in 1940

followed an intensivc rescarch projcct, the copolynrcr con14in-ing a srnall proportion of vinyl chloriclc bcing sclccted as nrbstsatis[ac(ory for 0bre production. The polynrer made by Dow wasspun by several l irms, including Pierce Plastics and Firestonelndustrial Producls Co., who nrarketed their saran l ibre undert l re namcs 'Permalon ' and 'Ve lon ' respec t ivc ly .

Production o[ saran fibres rvas subsequcntly taken up in othcrcountrics, and it is now establishcd as a speciality tcxti le f ibre.

.TYPIS OF POLYVINYI - IDENE CI ILOI i ID I I F IBRE

'l hc polyvinylidcnc chloridc fibrcs procluccrl todily are copolynrcrs

containing a snrall ( lcss than l5 pcr ccnt) proporlion of othcr

484

- U U L L ' L ' L ' L L L t L L L

II

B : S Y N ' r ' I I E T I C F I I } I I E S

nronomcrs , con ln ron ly v iny l ch lo r . i r l c . Othcr l ronontc rs r ru rv bci r rc l r rc lcd i r r r l l i nor f ro l lo l l ions , s r rc l r rs acry to r r i t t . i l c .' l 'hc

Amcrican Ir. l ' .C, rcgLrlirt ions rcstrjcI l l tc rrsc of l lrc lcrrrr,r4r.r/r lo l lrosc fibrcs spun fronr polyntcrs corrtairring t lcast g0pcr ccnt o[ vinyliclcnc chloriclc (scc bclorv), rud this (lcnnitiorl l lrscorlrc inlo gcncral usc fol such polyntcrs. -[t. covcl.s all lhc i lrrnor.-t t t t t po lyv iny l idc r rc ch lo r idc ty l ' c po ly r t rc rs r row r rscc j fo r sD in i r i r rgfibrcs,, and the propcrtics of saran fibrcs protlrrcccl Iry . i i t lcrcrinlanufacturcrs arc sull icicntly alikc in gcncrrl lrroltcrl ics for thctcrnl saran to bc o[ prtctical valuc.

Saran rvas producc<I originally in thc lorrn of hcavy dcnicrnronofilaments, and it is sti l l widcly uscd in tl l is forrir todav.I r , [o r ro f i la r r rcn ts a rc s ; l r rn i r r rou l ( l c ross-scc l io r r , i r r r t l a lso i r r avar ic ty o f f l l t a r rd c l l ip t i c l l c ross-scc l ions .

- .Sara l i s comnron ly spun-dycd, and a w idc rangc o [ co lourcdfibrcs is availablc.

NOMENCLATUITE

l'edcral Tradc Cottrtrtissiorr D efinitiotrThc gcncric lcrm.r.r/"al wils adopled by tltc U.S. Ircctcrlrl l .mclcCo.nr rn iss ion . fo r f ib rcs o I t l : c po tyv iny l idcnc ch tor i t l c typc , t l r co fT ic ia l dc f in i t ion bc i r rg as fo l lows:

Sqratr. A trlanufi lclurcd fibrc in wlrich tlrc l ibrc-fornring srrb_stancc is any long-chain synthctic polyllcr corrrposcd of l i lcast80 pcr ccn t by wc igh t o f v iny l idcnc ch lo r ic lc u r r i t s

( -c l I , - c .c l " - ) .

PRODUC'TION

Mononter SynlLcsis

(a) Vinylide nc Chloritle' I -hc rc

a re a nunrbcr o I ro r r l cs to thc f rcpr l r i l l i o t r o f v i r ry l i r t cncdiclrloridc, con'rlrrorrly via triclt lorocrrnnc,

.1 . ,2 -D ic l rJoroc th l r rc n l i y bc ch lo r i r ra tc t l to t f i c l r lo roc lh :u rc ( l ) ,rv l t i c - l r j s a lso fo l r r rc t l by t l rc c l t lo l in t t io r r o f v i r ry l c l r lo r . i t l c (2 ) o ictl lylelle (l).

485

L - L

, t

I . I N D B O O K O F T E X T I L E F I A R E S

Trichloroethane is conYcrted to vinylidene chloride, either by

pyrolysis at 400"C., or by treatmcnt with l irne (4). In cither case,

hydrochloric acid is rcmoved.

cHr ct cHrcl + c l ,

I ,2 -DICHLOROETHANE

C H r : C l l c t + C L ?

VINYL CHLORIDE

c H r : C H r + C t ,

( 1 ) > cH ,c r cH cL ,

TRICHLOROETHANE

C H . : 6 6 1 t

ETHYLENE VINYLIDENE DICHLORIDE

Production of Vinylidcnc Chloridc

(b) Vinyl Chloridc' Sec Pagc 447.

Polynrcrizrtion

Vinylidene chloride and the vinyl chloride or other co-monomer

are polymerizecl in aqueous cnltl lsion in the presence of.a-catalyst'

Commercial polymeri are commonly of molccular weight in the

region of 20,00G 22,000(

Spinnirrg l

The copolynrer is mclt spun through spinncrets at about 180"C''

the l i l iments being quenched rapidly before being drawn to

develop satisfactory tcnacitY.Pigmcnts may be incorporatcd in the molten polymer- belore

spiniing, t itaniun clioxide bcing uscd to provide a dull f i lament

Bv su i tab lc i rd ius tn rcn t o f the propor t ions o [ v iny l idcnc ch lo r idc

an,l uinyl chloridc in l l tc polynrcr, [ ibrcs can bc made witlt

so f tcn i r rg po in ts in thc r rngc 70-180"C. A typ ica l con lmcrc ia l

s r ran rnc l ts a t about 160-170"C.

486

l

t' I t i I 'II

n : s Y N ' r E t t c F l i : R u s

Sotan flow Cfutrt

487

{

__ .4

E L E C T R I C I I Y COMMON SALTNaCt

HYDROCEN CHLORIDEt lct

M E L T E X T R U S I O NI

cooLrN6Y

ORIENTATION

DycingSaran may be dyed by using lechniques and dyestu[Is similar tothosc uscd for vinyon and acetalc [ibres. Disperse dycs, forexanrple, are used, but the fastness properties are poor.

Conrmercial saran fibres are contmonly produced in a widerange of spun-dyed colours, and thcse are uscd in prcferencc todycing.

STIIUCTURE AND PROPER'IIES


PROCESSING

li i c Structurc xnd Appc:rrancc

The filamcnts are smooth-surfaced and regular. Theyround, oval or flat in cross-seclion,

Saran is a faint golden-yellow or straw colour, andluccnt in non-pignrcntcd form.

1ctlxci ly

Up to 20.3 cN/tex (2.3 g/tlen), wet or dry.Std. Loop: 6.2-9.7 cN/ tex (0.7- l . l g / t lcn) .Std. Knot : 8 .8-15.0 cN/ tex (1.0*1.7 g/den) .

Tensi le SlrcDgtlr

I ,050-3,15 0 kg/cm2 1 I 5,000-45,000 lb/ i r r2 ) .Elongalion

15 lo 30 per ccnt, wct of dry.

Elastic Rccorcry

98.5 per cent a t 3e longat ion .

A!crlrgc Stilhrcss

per cent elongation; 95 pcr ccnt at l0 per cenl

44.1- 88.3 cN/ tex (5- l0 g/den) .

Avcrrgc 'l oughDcss0.16-0.26

Spccit ic Gr:r l i ly

l . l - t ; t

may be

ts trans-

488

T - t ' ' L ] t I L t L ' \ " \ u \ ' [ ' [ ] ' ' \ ' | , . ' r L ' '

u : s Y N T l | U T t C F l n R r , s

lallec( of Moisturc

Regain: 0.1-1.0 per ccnt.A .bsorbcncy a t 70 'F . and 95 pcr ccn t r .h . : 0 .1 -1 .0 fc r ccn t .Moisture docs not swcll t lrc f ibrc, and it hls a ircgligiblc cllccton the ntechanical propcrtics.

t hcrnlal Propertics

Sof tcn ing po in t : I l5 -160.C.Sticking point: 99-104"C.Mel t ing po in t : l7 l .C .Saran f ib rcs n ray bc weakcnc t l i r t t c r pcra lu rcs bc low thc bo i l i r rcpoint of water. At 100'C., srran toics ntout ou"_rtri.,t oi ' i i istrength.

l;lanwnbility

Saran is a lmost non- f l rn rnrab lc , nnr l w i l l no t su fpor t coo lbus t ion .

Eftcct of Age

Ncgligiblc.

Iiflcct of Sulligb(

Good resistancc, but discolours slightly on prolongcd cxposurc.

Cherrrical Propcrlics

General

Cood rcsistance to bletchcs and to nlost conrnron chcnricals.Not corroded by salt spray.

Acids

Excellent rcsistance to nlost acids in all strcngths.

Alkolis

Exccllcnl resistancc to nost alk l is, cxccpl i lnltrro|l iunl hydroxidc,which causcs discolouration.

Iillcct of Orgllic Solvcnls

Not tl lcctcd by nlcohols or aliphalic hytlroc rbons. nronr ticnydrocilrbons, l lnlogcnatcd hydrocarborrs, kcloncs, cslcrs i lrdelhcrs lnay bc dctrinrcntal in varying dcgrccs. (l.cnrpcralurc is an

489

ll-'

I - - . - - . . . . n f , F ; n . F , _ T - ; _ I , J l 1 : l

H A N D D O O K O F T E X T I L E F I B R E S

importaot factor in the efiecls of any of these materials.) Solublein cyclohexanone, dioxan and tetrahydrofuran.

Irlsccts

Saran is not attacked by moth grubs or bectles.

Micro"orglnisnrs

Saran is not attackcd by mildew or bacteria.

Eleclrical PropertiesDieleclric conslant. Power Factor (1")

100 cycles:1,000 cycles:

1,000,000 cycles:

Refractive Indcx

L60

4.73.92.9

6

3

5 t o 1 5 Z OsrRArN (% ELoNcATToN)

Soran

I } : S Y N ' T I I E T I C T I r } R E S!

SARAN IN USE

Gcncral Chaiactcrislics

Saran is a fl_exiblc fibrc, with a soft wrrnt hrndlc. ,I-hc smoothrounded surface of rhe fibrc conrributcs ro rfr" ,"sisr,i,i." il '!Jii-

ing and the easy rcnlovfl l o[ dirt.

Mcchonical Propu!ics

Saran i-s- unusu,ally tougb aud durablc, wifh cxccllcnt f lcx rcsist-ancc. Woven fabrics lravc exccllcnt abrasion ,"rhtnn""-nnJ-aremarkable resistance to hard wear.

Spccilic G ravity

The spcci0c gravity of saran is fairly high. 'Ihis would count

against saran if the Iibrc had potentir ' i ly i i lporra,rt "frp^i"i"". i-uses.

Moisture

The moisturc absorption of saran is vcry low, ancl thc nrcchanicalp roper t ies o I s r ran fabr ics a rc unaf fcc tcd tV , , , . i r * " , L i , " " ' , , r "dimcnsionatty srabtc, an<t wastr ancl .rry "*ly "".i 'qiitui;;l i i,;low mo-isture absorption conlributcs to the ciccllcn t' .sl;,i; 'r".i::

tance of saran_ fabrics; iuk, food and driuk, .f"., ,ri" V' frl 'r",r, ou"Jwith soap and water.As saran is not uorntally used in making unrlcrrvcar lncl othcrgaunenls worn ncxt to thc skin, the low nroistrrr" absorption Jocsnot derrlcr lronr rhe valuc of rhc fibrc as ir doc; i;i i;; .i l";;apparcl Iibrcs.

Tlrcnnal ProperticsSaran tcnds to softcn at. tcrnpcraturcs so|lrcwhat lowcr thln thoscfa.vou.red for gcncral textile usc. Its low rcsistancc r" il"i: ';;;;ri";with its n_cgligiblc nroisrurc absorprio,,, h,,u; ;;;;i";; '; ir"i"#';;garmcnt fabrics.-l 'hc-norr-flanrrlrability

of saran ls an t|nportant assct, ls in lhccase of polyvinyl chloridc fibrcs, and sarari f,,frri., ". i",r,,,""i"ruscd in drapcrics, clc., \vhcrc a firc hnzlrd js nrcsc,ri_

Dttyi rontnent ol Conditi onsSlran has cxccllcnt rcsistancc to sunlight, agcing and gcnclrl

491


weathering conditions. It is completcly resistant to attack byinsccts and micro-organisms.

Chatrtical Rcsisttuce

The resistance of saran to most conlmon chemicals is excellent,and it wil l withstand most of thc bleaches and other chemicalscncountered in nonnal proccssing. It is attacked by ccrtain sol-vcnts, but is not afected by those normally used in dry cleaning.Pcrchlorocthylcne shorrld be avoidcd.

\Yashing

Saran wil l wash quickly and easily in soap and lukewarm water.

It should be rvashed by hand, and Sreat care is necessary to en-sure that the temperature of the water is kept as low as possible'

Dry ing

Fabrics should be drip dricd at roonr tcmpctaturc. Tumblc dryingshould not be uscd,lroning

Saran labrics do not generally nced ironing, but if ironing isnccessary a wct press cloth must be uged. The tcmperature mustbe as low as possible.

Dry Clcaning

Stoddard solvcnt is recomnlended for saran. Perchloroethyleneshould be avoidcd.

End.Uscs

Despitc the restrictions itnposccl on end-uscs by the low softcni{8

tempcrature of saran, the special charactcristics of the fibre haVeensured it a n)arket of considcrable importance in the texti letrade,

Exantples ol A pplications

Cirr seut covers; luggage; fi l tcr fabric; handbags;fcnder cloths; drop cloths; ropc; car and public vchicle trp-

holstery; outdoor ftrrniiure tapc and broad [abric; insect screen-

ing; beach umbrellas; doll hair; mannikin wigs; f ishing lurcs;

scouring pads; vacuum cleaner hose covering; gri l le fabrics;shade cloth.

492

f f i T _ ] - U U L L I L i t ' U U , L j t ' U ' \ . , , J

A : S Y N ' r I I E T I C F I U R E S

POLYVINYL ALCOIIOL FI BITES

Iribrcs spun frorn polymers or copolynrcrs of vinyl alcohol :

CII!=CHOH -) -CI tr-CFl-CI I,-C11-I I

Vinyl Alcohol

I NTRODUCTION

or'l o t rPolyv i r ry l A lcohol

Po lyv iny l a lcoho l was l l r s t syn t l rcs izcd in Ccr r ru rny jn I9 l . l , a r rdrorcs w€rc s!bscqucntly produccrl irr l9Jl by Wackcr_Chcrrric\ r .n r .D, i { . under l l )e n t r r rc .Syntho f i l ' .

. Thc polyvinyl alcohcl molcculc conltios fl grctrt nurlrbcr oIhydroxy l g ror rps , r r rd po lyv iny l r r l coho l i t sc l f i s io l r rb lc in wutc j r .l l r c - -uscs fo r 'Syr r tho l i l ' ,

thc rc fo rc , wcrc l i r r r i t c t l to sncc i : r l i zcdapplications for which a wirlcr-solublc tibrc is of *,fu" f i""Alginatc Fibrcs, pagc 148).

. ln t l t c la te 1930s, po lyv iny l a lcoho l f ib rcs l t r i r c tcd a g rc i l t dc loL a l len t ion in Japan. In 19 j9 , l . Srk r r r rc la , S . Lcc rn t t co_workers at the Kyoto Univcrsity discovcrccl a proccss for pro_ducing a rvater-rcsistant.polyvinyl alcohol f ibrc by dry hclt tr lcni-nrcnt and acetalizatiou. ln the samc year, lvl. yaziwa :rnd hiscolla_borators at the Kancgafuchi Spinning Co. Lkl. inrlcpcntlcntivrlcveloped a wet hcat lreatr)rcot (hcat trc;tnrcnt in a sali solrri ioirunder pressure).

Eflorts rverc ntadc to ntanrrfaclltrc wtrlcr-rqiisl i lnt nolvvinvlalcohol Ibrc by thc-Japrn Synlhctic lcxti lc ttcscarch n syrci1,ti., ir.Krnega.Iuchi Spinning Co. Ltd., Ktrrashiki l{;ryon Co. l_tcl., rnrio rhcrs . I t l c work was in tc r rup ted by Wor ld War l l , howcvcr , l r r rdrt wes not unti l 1950 that thc Kurashiki l l .ayon Co. Ltd rnd tlrcN ich ibo Co. .L td . bcgrn produc ing t l rc f i r s t po lyv iny l u lco t ro lro rcs undcr u tc t radc n f ln tcs . l (u ra lon '

n t l . l r4c rv lon ' rcsDcct ivc ly .

. ' l ' l t c

ou tpu t o lpo lyv i l t y l a lco l ro l l j b rc l rns i r rc r tasc t l L : rp i t l l v inJ rpar ) . I ' i l ) rc i s a lso pLoduccr l in o t l l c r count r i cs u f l l t c l i l r i i ; r s tt r ) ( | c tsc \v l te Ic .

493

" n I I t t t F F n F, F: f', F h_}-t}I I A N D I ] O O K O F T E X T I L E F I I ] R E S

TYPES OF POLYVINYL ALCOHOL FIBRE

Polyvinyl alcohol l lbrcs arc commonly insolubil izcd altcr spin-ning by heat treatment and lreatmcnt with formaldelrydc, and thistype of f ibrc represcnts the bulk of the output. It is manufacturcdas continuous fi lament yarns, staple and tow. Staple is availablein sizes and deniers suitable for processing on the col.ton, woollenand worsted systems. Tow is processed on the usual types oftow-to-top syste ms.

Polyvinyl alcohol f ibres are also acetalized with ald€hydesother than formaldehyde, providing l lbres of modified character-istics. Benzaldehyde is used, for exanrple, to produce libres ofhigh resil ience which are used in uniforms, ladics'and children'sc lo th ing .

lvatcr.Solulrlc Fibre

Polyvinyl alcohol f ibre is produced without the heat and aldehydetrcatmenls which bring about water-insolubil ity. These water.soluble fibrcs are used for special purposes, such as surgicalthrcads. lvl ixed with other fibres or yarns, soluble polyvinyl al-coho[ f ibrcs scrve as scaflolding fibres and yarns; when the fabrichas been made, the polyvinyl alcohol f ibres arc washed out withhot water.

/

NOMENCLATUI{E

In Japan, po lyv iny l a lcoho lnanrc virrylor, ln thc U.S.A.,

fibrcs rrc knownU.K. , and o lhcr

414

by thc gcncnccount r i cs wh ich

'}:-r;-1B : S Y N ' n l c T t c r t D R E S

usc the lcrm vinyon tor polyvinyl chlorit lc typc fibrcs, lhcrc isoangcr o I con lUsrou bc lwccn thc two c losc ly -s in t i la r l c f l r rs , an t lt lrc name yr'rral has conrc into usc for dcscribiirg polyviuyl l lcoholfibres. ifhis is rhe lcrm adoprccl ofl icially Uv if," 'U.S1 f..J"i^ir ri l( lc L omn)lsslon.

Fult:ral Trade Connission Dcfinitiotrf lre gcncric tcrnr-r' irrrrl rvas arJoptcd by thc U,S. Fcdcrnl

.frrdcLonlmrssron tor l ibrcs of thc polyvinyl alcohol typc, thc oll icialdefinit ion being as follows:

Vinal. A manuftcturcd fibrc in which thc fitrrc-fornrirrc sub-slance is any long-chain synthctic polynlcr conrDoscrl of l i tcasr)u

.per ccn t by wc igh t o [ v iny l r l coho l un i ts ( _ CH. ,CH.Ol t _ )and tn whrch thc to ta l o l thc v iny l a lcoho l un i l s i r r rd , ,uy nn" o inrore of the various aceti l l units is at lcast g5 pcr c"nf t,y ,u"igi iof thc nbrc.

PRODUCTION

Vinyl alcohol js an unstablc nralcriat, ancl polyvinyl alcohol isntade indirectly by thc hydrolysis of polyviriyl

-accfttc.

Mononlcr Syn(hcsis

Vi yl AcctoteVinyl acetale is rnadc by the rcaction o[ rcclylcnc (or cthylcnc)with acctic acid in tbe prcscncc of a cntalyst :

CH*-CH j. CH.,COOH -> CH, =CI.tOCOCI{.Acety lcne Acet ic Ac id V iny l Acc t l t c

I 'olynrcrizntion; S:rponitictl i rThc vinyl acctate is dissolvcd in nrcthanol, and is polynrcrizcdwith the help. of a catalyst (c.g. pcroxidc or. nro_.o,,lpJ,u,rJi, ioii, iIng po lyvny l acc t i t c ( l ) . Crus t ic soda is a r ldcd lo l l t c n rc th rno lsolution,. brjng.ing a-bout saponification of thc polyvinyl acctl icto.polyvinyl alcohol (2). This is prccipitarc<t tron'ttrc incrhriri i i lsolution, prcsscd and dricd.

495

I I , { N D I ] O O K O F T E X T I L E F I B R E S

cH,:oi o cocHr -lU- -fc,,-cxJ

ococHl

VINYL ACETATE POLYVINYL ACETATE

{cx. -cr - }O H

POLYVINYL ALCOHOT

Production of polyvinyl alcohol

Spinning

Wa S pittniug

Polyvinyl alcohol f ibres are comntonly produced by wet spinning.The polymcr is dissolvcd in walcr to fornr a l4-16 Dcr cent solu-tion, which is f i l tcred and pumpcd through spinncicts. The jctscnrerge into an aqueous coagulating bath containing sodium sul-phate solution.

Dry lMelt Spinning

Polyvinyl alcohol f ibres nray also be spun by a proccss whicl.rcombincs fcaturcs of dry and mclt spinning. Thc polyrhcr is dis-solved in water undcr pressure and made into a highly concen-tratcd solution (30-50 per cenl). The hot nrolten mass is forcedthrough spiunerets, and the jcts cmerge into a hot air streanrrvhich evaporatcs thc solvent to lcave solid 0laments of polyvinylalcohol. These are hot drawn.

Insolubil ization

Polyvinyl alcohol f ibrcs produccd by thc rcgular wet spinningprocess are heat treated, e.g. at about 240'C. This produces anrore compact I ibre in which hydrogen bonding bctwecn thehydroxyl groups of polymer molecules is grcatly intcnsil ied. Thisis connrntcd by the incrcasc in spccific gravity which takcs placc,and by X-ray cxamination of lhe heat trcated l ibrc.

flcnl trcittnlcnl is followcd by acetalization, usrrally rvith fornt-

496

U L ' L ' L ' t ' [ " L o L ' L . L ' L ] u

B : S Y N T } I E T I C F I B R E S

aldchydc. Acctal grolrps arq fornrcd, rvhich nray l ink adiaccntnyoroxyl groups on lhc $nlc nrolcculc (2), or crcalc crosi-l irrksbelwcen -hydrox.yl groups on two adjoiriirig nrol".,,i";' it

'r:i;;qegree or acetattzilt ion achicvcd induslria y is bctwccrr 3d and 40mol per cent.

-cHz - cH -I

o H ( t )

OHI- c H r - c H -

- c H r - c H -

Io

I- cH, - cH -

. _ . . - ( 2 ) _ c H r _ c H _ c t , t , _ c l l-r i Lnru+ | |

o _ c l t r _ o

* c H , - c H - c H r - C H -

OH OH

- cHr - cH -

OH+ cx"o __ll']-_r_

OH

-cH , - l r r -

Insolubil ization of polyvinyl Alcohol

Aldehydcs olhcr than fornraldchyde nray bc uscd in lhc accll l i-zation. Dcnzaldehyde, for cxnnrplc, proviclcs " nb; oi-l; i ; i ,resttlcnce; atdchydcs conlaining active groupings such as anti iogroups may bc uscd to confcr spccial <tyc ail iniiy ou rfrc nirc."-

PROCESSING

I)csizirrg'f ltc.rrsua.l

tcchniqrrcs arc usctl, <.lcpcndirrg oD lltc nallrrc of f l lcs rzc u ra t l l i l s bcc

uscd . po lyv iny l a lcoho l a r r t l o thcr w l tc r -so lub lc

497

- cHr - cH -

oI

!11'?- cl l2 - ct. t -

I I A N D I } O O K O F T I X T I L E F I B R E S

CALCIUM CARBIDEC a C ?

VINYL ACETATE

SODIUM ACETATE

causlrc sooAN a O H

WET SPINNING

IDRYING

HEAT TREATMENT

IALDEHYOE TREATMENT

I'ol l ,vi tryl Alcohol (V inal\ Fibrc Flow Clnrt

498

_-I: f , h h h - - ts - F; f, h h fr h h h hl

S Y N T I I E T I C T I D R E S

srzcs nray bc rcnlovcd withrcnrovcd with an enzytn tic

t s

Scouring

Alka l ine_ scou r ing t rcatncnls , such as k icr boi l iug, tcnd to shr i r rkpolyvinyl alcohol goods, and cruse y"tto*iug.- .t-t,"y ar"

-t .riavor'ded.

A soap rinsing with ncutrll dctcrgcnt is prcfcrrcd, c.g. for 30minulcs at 80-90'C., using a 0.5 pcr ccnt solution.

Il lcrcLing

l)lcaching by hydrogcn pcroxidc, sulphur rl ioxidc antl siuri lur.agents is nol ellcctivc, Chlorinc blcaclics arc prcfcrrccl.

Flypochlorite ancl chloritc blcachcs arc uscd' cllcctivciy for rhcbleaching of polyvinyl alcohol f ibrcs.

Optical blcaching agcnts nray bc uscrl aftcr t lrc norrnll blclrch.

Dycing

Po lyv iny l a lco l ro l f ib rcs havc a good n t l in i t y fo r ( l ycs t r r . s ; t l r c

| lu res rcse t ) tb lc co t ton nd o thcr cc l lu los ic l ib rcs in l l i r v in rhydroxyl grorrps along tlrc nrolccule. . l.hc

follorviu;1 tvr.,", ui.tu.,]sltrl l nray bc uscd: dirccl, acid, basic, nrctul conrplc,'x, i i , l i i f ,"r, "i,r.Iraphthol, acetale.

h) 100 pcr cent Polyvirtyl /lcolrol Fibrc

Dircct Dyestu[Js

These arc gcncra l l y o I low fas tncss to sur ) l ig l t t anc l rv l rsh i r r r : .lnd are uscd for l ight sltadcs whcrc faslncss is uot nn i,,,t,o,i", i ifaclor.

Acid Dycst ulJs

. In gcnera l , ac id dycs lu lTs too arc o f in i r ( l cqUi t tc l ig l t t D( l w ls l r

ras lncss whcn uscd wt lh po lyv i t ry l a lcoho l f ib rcs .

Basic DyestulJs

B ls ic dycs lu f fs a rc gcncra l l y poor i l I igh t fas lncss w l rcn t rsc t lon po tyvrny l a lco l ro l [ ib rcs . ' fhc fas tncss is i r r rp rovc t l by t rsc o fa nordant , .bu t lhcse dycs arc no l rccon ln lcndcd whcrc s r rn l ig l t tresistant is inlportant.

wtrnr walcr at 80-90.C. .Starchdcsizing agcnt, c.g. diastasc.

499

T I N D D O O K O F T E X T I L E F I B R E S

14etal Cont ple x DyestflJsl:2 typc mctal complex dycstuffs are uscd very eficctively for

dycing polyvinyl alcohol fibrcs; they are distinguishcd by excel-lcnt light fastness.

Sulphur DyestuAsSomc sulphur colours and sulphur vat colours have good dyeing

a(finity lor polyvinyl alcohol fibrcs. Thc colours arc not brill iant.

Yat DycsrulJsThese are the nrost ellective dyes for use with polyvinyl alcohol,

providing a range of bright colours of excelleut fastness. A widerange oI shades is available.

Naphthol DycstutsNaphthol dyes are used for dycing polyvinyl alcohol fibrcs,

providing a range of bright, fast colours.

Acctate DyestulJsAcetate dyestufls are suitable gencrally for the production of

l ight shadcs.

(l:\ Polyvinyl Alcolol lCellulosic Fibrc Ble nds

Sulphur arrl Sulphur Vat DyestulJsAftcr-dyeing with ntetal complcx dyes may be necessary to

obtain good results.

Vat DyestulJsAfter-dycing with ntetal complex dycs nray be necessary to

obtain good results.

Naplthol Dyestu0sThese dyes are used preferably when blends contain a high

propor t ion o[ cot ton.

(c) Polyvinyl / lcohol lllrool Blends

Dircct acid, acid nrordant and mordant dyestulTs nray be used.

500

-1 - - l r -1 - l ] . [ , [ ' l r I r I

I } : S Y N T I I E l ' I C r t B R E S

Acct;ltc dycs rnay bc uscd for aflcr_dycing thc polyvinyl nlcoholfi brc.

Direct and acid dycstufls arc uscd nrainly for light shadcs.

I'rinti|lg

Resin p igrnent pr in l ing is uscd c l lcct ivc ly wi th polyv iny l a lcoholgoods. Aftcr bcing prinrcd and tJricd, rirc frrlrr.ic i. t,..,-rr""il.ito completc polynrcrization of thc rcsin and sct thc pig";;;i;i;;;;in (hc fibre.

- -|"-b]i:: prinrcd in.rhis way arc fast to srrrrlighr arrd rvashing

ano colours arc bflcbt.

Singcing

Polyvinyl alcohol f ibrc docs not burn rcatl i ly, ;rnd it r.s not c:rsilvsingcd cllcctjvcly. 1'hc lurnps oI burncd tibrc tcntl to sri"i ru i i , lsurlace of thc fabric.

. If polyvinyl alcohol sizc has bccn usccl on thc flbric, this nrustbc rernovcd by dcsiz ing bcforc lhc. t"r t , i r . l ; ; ; ; i i . i f i r , i , ' r i ' , , i , ill?,t_".'_11! ]l*t may. irrsolu bilizc rhc polyvi0yt irlcohot sizc, rrr:rkirrg[s rcmova l morc d imcu l t .

STITUCTURE AND PROPERTIES

Irinc Structurc and AppclranceFibres are smooth-surfaccd. Thcy arc whitc, wirh a silkJikc lustrc._,

l nc .cross-sect I on js gcncrrl ly U_shapcd, I ikc a fl l l tc|cd tubc.,r

nere ts a pronounccd skin laycr, which is nlorc crystall inc tl l tnlre corc. Mean vlluc o[ crystall inity is about 50 pcr ccnt.'l'cnacity

cN/tex(g/tlel )Dry

Wet

Elorrgal ionDryWct

I .22l0-26

l l - 2 0

Staple IIigh_.j'cnocity lVnu_SolublcFikutlent Filonrcnt

33 .5 _5 4. .1 53.0_75. t 26.5__- t5.3-(J.q*(,2) (6.0-8.s) (1.0_4.0)28.3_44.t 44.1*67 .)

. (1.2_5.0) (5.0_7.6)(pcr cent)

l1-26t4-2'1

501

I

TF. F. f F. F, F. F, N F. F. F. F. F.FT I A N D B O O K O F T E X T I L E F I B R E S

Stople HigltTetncityFilattrc

Itlaslic Rccovcry (per ccnt)From 3 per cent strain 65-85 70-90From 5 per ccnt strir in 50 60

In i t ia l l v fodu lus c \ /1s1 220_6 lg 6 lg_1,5g9(g/ t lcn) (2s-70) (70- 180)

Young's lvlodulus (kg./mnr")300-800 800-2,000

Averigc Stifncss cN/tex 150_459(g/dcn) (r7 _52)

Avctngc TouShllcss

0.41*0.52

Specif ic Gravity1 .26-1.30 1.2G1.30

-l 'hc following propcrtics rcfcr to thc rcgular (watcr,insolublc)

polyvinyt alcohol f ibre.

Thcrntal Propcrlics

Polyvinyl alcohol f ibrc undcrgocs a shrinkagc of l0 pcr220-230'C. At 220"C. it bcgius to turn yellow, and itand softens at 230-250'C.

In boil ing water (30 nrinutes immcrsion) shrinkagcper ccnt.

Flannrability

l 'olyvinyl alcohol f ibrc docs not burn readily.

llllccl of A8c

Nonc

ll/atcr-SolubleFilarttent

85-95

44t-795(s0-e0)

600-l,000

Ellcc( of luoislurel{cgain (per cent)Absorbency at

100 pcr cent r.h.

4.5-5.0

12.0 per cent

3.0-5.0

1.26- 1.30

9.0

ccrr t a tshr inks

is 0.2

502 503


Eltect of SuoliSht

Slightly a{Iccted after 100 days cxposurc, brrt loscs strcngthmore prolonged exposure. Tlre colour rcrnains good.

Chcnlicll Propcrtics

Acitls

Polyvinyl alcohol f ibre has a good rcsislancc to aci<.ls undcrnornlal conditions. Hot or conccntrated nrincral ircids clusc swcll-ing aud shrinkage.

Alkalis

Rcs is tance is gcncra l l y good. S t rong a lka l i s causc yc l low ing , bu ttcnacity ls not allectcd.

Polyvinyl Alcohol Ftbre ( 'M ewlon')

rl, 1r iI I I A N D A O O K O I i T E X T I L B F I D R E S

Gerrcrol

Resistancc is gcnerally good.

Elloct of Organic Solyenls

Incrt to anirnal, vegetable and mineral oils, and to most commonorganic solvents. Swelled or dissolved by pbenol, cresol, formicacid and hot pyridine.

Insccts

Completely resistant

I\ l icro.organisnls

Conlplctely rcsistant

Elcctriqtl I 'ropcrlics

Surface resistivity (nrcasured on yarns) l.3x 10tl ohrns/cm.

POLYVINYL ALCOHOL FIBRES IN USE

Polyvinyl alcohol fibres have the tlexibilit.y that is associated witha flattened-tube type of cross-section, and the handle of fabricsmade from these fibres is excellcnt. Polyvinyl alcohol fabrjcs aresoft and warm, and lcel very comfortable when worn next lothe skin.

Mechatical PropertiasFabrics bave high tensile and bursting strengtl.l, and excellentimpact and abrasion resistancc. Thcy are extremely durablc andhard wcaring.

Thc clastic recovery of polyvinyl alcohol fibrcs is on the lowside, and this would suggest that dimensional stabilitv and wrinkleresistance may not be high.

Spccific CravityThe specific grayity is lowcr than that of cotton or ravon. andabout lhe sanrc as s i lk , wool and acctate.

M oist urc Relat ionshi ps-fhc

rcgain is highcr than that o[ nrost vinyl-type fibrcs due to

504

t \:-L.*-L l--L l-L ' -t ' L : , 1 - . - t - l' L , L L : I ;

D : S Y N T I I E T I C F I B R E S

lhc high proportion of hydroxyl groups whiclr rcnrain evcn irrthe acetalized fibre. Dcspitc lhis, thc mcchanical propcrtics arcnot unduly allected by watcr.

1'he abil ity to absorb ntoisturc contributcs to thc conrlort o[garmenls worn Dexl to thc skin.

Thernnl Properties'fhe

shrinkagc/soflcning tcnlpcraturc rangc, bcginning at aborrt22W23Q'C., is a l itt le on thc low sidc for sornc tcxti lc rpplicr-tions, but is adequate for most purposcs.

Polyvinyl alcohol f ibres do not hcat-sct as cllcctivcly as nylon,polycster and othcr thernropluslic l ibrcs.

Fabrics made lrom polyvinyl alcohol f ibrcs rvil l burn only withdifi iculty, much depending, as always, on othcr factors such usfinishcs used, cloth construction, ctc.

D nviro rmrcnI al Condi ti ons

Polyvinyl alcohol f ibres are resistant to insccl.s, rrricro-orgrnisnrsand othcr influcnccs cncountcred in outrloor applicl l iorrs.

CIrcnticol Resis!ance

The high resistancc to acids, alkalis and many othcr chcrrricnls isan important factor in thc industrial applicatiols of polyvinylalcohol f ibres.

Cost

Polyvinyl alcohol I ibres are potenlially very clrcap, and lhcirfuturc would seem to l ic in thc field o[ hard-wcaring, low-costfabrics and garments.

Washirrg

Polyvinyl alcohol fabrics may bc washcd wirhout dil l iculty, nospecial precautions bcing ncccssary.

Dryirrg

Fabrics are quick-drying, and any of thc normal mctlrods mtybe used.

Ironirg

Carmelts may bc ironcd safcly bclow 150'C. whcn dry,prcfcrably

505

r i r il l , t l , t

tril ll;r

I F'�lH A N D A O O K O F T E X T I L E F I B R E S

at 100-ll0'C. (rayon setling). Wet fabrics should not be ironed,as thcrc is a tenderlcy for the rnatcrial to harden.

Dry ClcaningPolyvinyl alcohol fabrics are dry cleaned without dimculty, andare not aflected by the solvents commonly used.

End-Uses

ln Japan, rvherc polyvinyl alcohol f ibres have beconre of majorinrportance, they are being used in virtually every texti le f i i ld,rarrging fronr the finest rvearing apparcl to thc toughest ol i ldustrialapp l i ca t ions .

Apparel

Staplc fibre is used in 100 per cent form, or as blends with otherfibres. Excellent materials are made by blending with cotton orrayon,

Apparel applications iuclude materials such as denims, poplins,shirtings, serges, gabardines, suitings, l inings, etc. These are madeinto all manner of garments, including uniforms, sportwear, suits,dresses, stockings, socks, gloves, hats, children's clothing andfoundation garments.

In all these apparel applications, Lhe hard-weariog qualit ies ofpolyvinyl alcohol are associated with warm, con.rfortable handleand easy-washabil ity.

I{onte Furr:jshittg Fabrics, etc.

Polyvinyl alcohol fabrics are used for curtains, upholstery, car-pets, umbrellas, tableclotbs, sheets and the l ike.

I rrdust rial A pplicotions

The durabil ity, chemical resistance, nater resistance, strength andresistance to outdoor exposure have enabled polyvinyl alcoholfibres to establish many important industrial end-uses. They arenradc into fishing nets, ropcs, hoscs, tarpaulins, convcyor bclls,tyrc cords, I i l ter cloths, tents and sacks for grain storage.

506 507

t l": I - - - - - [l - - li r . r n r;B : S Y N T I I D T I C F I A R E S

Monoli lamcnts trc uscd for l) l king synthclic bristlcs, nd fornets used in cultivating scawced,

Water-Soluble Polyvinyl Alcohol Fibrc

A small proportion of the output of polyviuyl alcohol l ibrc con-sists of l ibre wlrich has not. bccn hcat-trcatcd or acctalizctl to rcn-der it insoluble in water. These watcr-solublc {ibrcs arc uscd forspecial applications in which thcir solubil ity is irdvantagcous, c.g.surgical threads and scaflolding fibrcs. Frabrics of novcl cllcctsmay be obtained by knitt ing or wcaving yarns spun from blcndscontaining polyvinyl alcohol f ibrcs; lacs and othcr opcnworkfabrics are made by incorporating polyvinyl nlcohol yarns whichare subsequently washed out.

Important uscs incluclc base cloth for Cuipurc crrrbroiclcry,draw thrcads in knitt ing half-hose socks an(l swcatcrs, wc[t]cssfelts for paper nraking, support for low-strcugth yurrs, c.g. lorv-twist wool rnd cotton yarns.


508

; r l T - 1 r - 1 r l r l r l r l f l

509

I [ r [ r I

A : S Y N ' I ' I I I , , I ' t C F I N R E S

POLYI'E rI{N FLUOIiOE fFIYLENE I;IDItES

l;ibrcs sptrn from polymers of tctraflrrorocthylcnc:

C F 2 = C F z

F F F F F I :t t t t t l-____t_ _-_ c_c_c_c_c_c___t t t t t tF F F F F F

TETRAFLUOROETHYLENE

I NTRODUCTION

P O L Y T E T R A F L U O R O E T H Y L E N E( P T F E )

i':._,*i*,t j#i[i:",,iii,:;*.'":,il;ixi,T,,l"ll,,i:;lt;'fi I ;::i " lii:, "Jit.,;l, [: i JJil, I *l J;,ff itfl I tff :ttuoroc thy lcnc . had po lynrc r izcd , fo r r r r i r rg po ly tc t ra l l " " , ; ; ; , ; i ; ; , ;l nc ncw potyn lc r l ) i l d u l lusu i l l and .po tcn t i r l l y usc f r r l ; r r .o |c r l i cs ,and cllorts were nradc to devel,rr4 a n y di rn c u r r i ei *;;; ; ; ;,'.-,"",i ;: ;:":.:;X, lf li,,," L j'/'"',1',1;,fiidiii"iilf [:';:iffi ]Jl:li,J;T:,.T;lt;;;l;f ",,"jt;undcr the trade name .'I 'el lon'.

, "'T:1,::;i;,,:ifl:ll,ll,,:".'i"" il,;:,l,y :1,1i'; lilf JH,;i,,"T;ll,i':l l,1l1,'l.ffjll'r:T,""";:""f'i"ro'ii" anJ n;;;r;; ;;' h"1ar norrnal t"mp"ratur..," an<rl; ;fill#r:"[Tl j:',:'i:r::1ill::

;L!:'"i"ii1,l'$':'3: ;,|ff ;1xifi pro'ti"' rL ii"gi'i' iffi;;;;:

:dixii:"yll''""Yfl ",,;,,1T:l'.":l;",.:i,u",'li"",,llllllll:,:;j[i i,-!;p*l't,ll,ili*, J]ii'ii',,y.i.h"!::';::t';*,,,:,:lll;;fiiiii:-,

conrinucd lo scryc ns a spccirt_-pur.posc pi;i;;;;;In 1954, ' ' fcflon,

f ibrc was in

:;mff ll;li#il"'ffi .,""'r,,*"lj",,,",.".';:lil"hi]lf UT":r;:

LF1 f " l f " i t t F tFEn f rFFHf r -F - l - ] : ] ' JI l i l j


and is p roduced in rc le l i ve ly smal l amoun ls , bu t i t hasnurnber oI highly specializcd applications for whichfibre is cqually satisfactory.

found arlo othcr

Polytelranuorocthylcrre is comrrronly known by the init ialsP.T.F.E., whicb is a conyenie[t lvay of avoiding the unwieldychcnrical nanrc. Thc fibrcs spun frotn the polyure-r are describcias P.T.F.E. f ibres, and thcy arc conlnonly inclucled in the nroregencral ternl fluorocarbons or lluoroltolymers, which inclucle othern'l i l tcl i i l ls wilh a high proportiou of I luoriDc irtonts as substituent.son thc carbo| chain of the polynrer nrolccule.

Thcrc is no U.S. Fedcral Tradc Commission (lcfi l i t ion lo coverP.' l ' .F.E. tbrcs. Thc uscs of thc fibrcs arc spccializccl ancl l icoutside the gcncrirl lexti le f icld; an oll icial definit ion of the F..I..C.typc would serve l itt le uscfLrl purposc,

Pti.oDUclloN

l\lononrcr Syutbcsis'1.etofuoroetItyle

ne

Calciurn fluoride (fluorspar) is reacled with sulphuric acicl toforn hydrogen I]uoridc (l). This is relcred wiih chlorofornlproducing chlorodifluoronrcthane (2). pyrolysis of the lattcr ai600-800"C. gives tetralluoroethylene (3).

NON4ENCLATUI{E

cf{LoRoFonM

cF, cF. + 2HC1.

TETRAFLUOROETHYLENE

caFa + H,sor -lll. zHr * "uro.

2HF + CHCI , cHc r F , + zHCt

CHLORODIFLUONOMETIIANE

t3) ,/.

5 1 0 5 l I

B : . S Y N r . I t ! . . t . 1 c F I D R E S

Polyltcr izl t ion' l 'ctra

f luoroethylene is pLrr i f icd and polynrcrizccl un(lcr hcat trndpressure in stainlcss stccl autoclavcs in tl ic prcscncc uf " i,.,;*;, i;-type catalyst. Thc rcaclion takcs placc rapi<lly, rvith ff i" r"f"u"of hcrt, and must bc kcpt carefti l ly rrndcr ci",,r"i i ;: i .. r.. l i . i ,ronrcd as wh i tc pow( lc r wh ic l r i s s r rbscqr rcn l ty w i rs l rc t l i r r r t ld r i cd .

Spirnirrg

P.T.F.E. is insolublc and it <lccomposcs bcforc rncll ing, lt cannotbe spun,, thereforc, by the dry, wct o-r nrclt .pl"ui"r,"r*f ,, i i i i i i".commonly used fo r p roduc ing l ib rcs f ro rn syr r thc t i c po lv l rc r i - I trvas nccessary to devisc spccial tcclrniqucs for sirinnirrg thcpolymcr.

In thc produclion of p.T.F.E. f ibrc, t lrc polynrcrizlt ion iscirrricd _o_rrt in such a wiry irs ro protlrrcc a rtisl icrsion l i,, i i" l i i i , i , i

i l l )o r r . t ) pc r cc l t o f t l t c l )o lyn lc r .

. l .hc l inc ; l r r r t i c lcs in t l t i :o rspers ron are r rbbonJ ikc in sh lpc .

Whcn. tlrc polynrcrizrr t io n i i conrplctccl. thc rl isrrcrsiorr i,rcx t rudcd th rough a sp inncrc t , thc j c ts c r r rc rg i r rg i , , r . , ,u i , , , , i , "u , , .coagu lar lng

-ba th cons is t ing o [ a d i lu tc so l r r t ion o f l ryc l roch lo I i c:rcro.. r,te dtspersion is co;rgulatcd. the pilr l iclcs ut p.t..F,L:.nororng togc thcr ns wcak f i l i rn ren ls i r r wh ich thc par t i c lcs rc l j t i t lcntircly separal.e.'fhc

fi laments arc healed rapidly to about. 3g5.C., rvhcrc thcvare nraintained for a fcw scconds. -l.hc pofvu,", pnrri. i .r ' ,r i i

sinle.rcd, and fusc inlo l cohcrcnt nlanrcnt. ' i t i is I i q".,"f,"iquickly, and drawD at roonr tclnpcralurc to l l lrcc or forrr l intcsr rs ong lu iu tenAlh .

^ ,PT.F .E, f ib rcs p roduccr l in th is way arc n l i l r kc tcd ; rs r r ru l t i -| lr irnleot )aflts, staplc l lbrc and tow.

PIiOCESSING

Blcachirrg

P,T.F.E. f ibrc has a nro lcd [rrowrr or t irn nlpcirritncc, l)ul i lcan be blcachcd cffectivclv-

. Exposure of thc l ibrc to fhc rir for 3-6 days at 260"C. rvil lbring about partial blcaching to a grcy. I, l igircr tcrnpcr:;rrrrrcs

l tA N D r looK oF ' l EX l lLE F l l l l l l l s

rcduce the l inrc l lcccssary, bul this ntay be otl-set by sontcdcgrad l t ion o I lhc f ib re .

Wct oxidatior) with hot miucral acid mixtures is thc quickcstand nrost cllectivc way of bleacbing P.T.F.E. f ibre, produciuga purc wb i tc .

Dl cirrg

P.T.F.E. f ibrcs arc virtually undycable.

Siziug

In proccssilg lo!v-twist continuous-fi lament yarns through plying,trvisting, spooling, rvarping aud wcaving, it is preferable to usea siziDg agent. A 2 per cenl coating of a polyvinyl alcohol typeagcnt is rcconrllrcnded. lt kceps the {i lamellts together duringquilt ing, warping or weaving, and may be removed easily by asubscqucnt scour ing o I thc fabr ic .

Plicd fi larncnt yarns or highly twistcrl singlc cnd yarns maybe processed without sizing.

Tl ing

A dorrblc weavcl's knol is rccornrDcnded for tyiog togetl]er twocontinuous fi lamcnt yarfls of l ' . ' f .F.E.

Spinnirg Staplc ff ibrc

The slick, waxy fcel oI P.T.F.E. conlinuous-[i lanent yarn istrndesirrblc in some applications, such as protective garments.l l thcse cases, spun yar[ made from P.T.F.E. f ibre nray be used.

Thc proccssing of a low friction fibre such as P.T.F.E. staplecrcatcs spccial diff icult ics. Card rvebs and slivcr tcnd to fall apartrundcr their own rveight. Tlrc low cohesion of thc l l lamcnls canbc overcome lo sonre dcgree by blending in 3 per ccnt of rayonstaplc. Porvdering with rosin is also efiective, a|ld lhe additionof snrall qualti l ics of asbestos may help with carcliug and spinning.

Dircct Spi0nirg

Spun yarns of I ' . ' l ' .F.E. f ibrc arc ntadc satisfactori ly by directspinning. 1'hc fi laments in a hcavy contiruor.rs-l i lalncnt, low-twisltow arc brokcn in random fashion, and thc nbrcs are twisted intoa spun s{aplc yarn. Thc troublcsonre carding slep is thuse l im ina led en t i rc lv .

5t2

' L ] L , L ] L - ' I ' U U U

A : S Y N T I I E T I C F I B f t E S

Excellcnt yarn unifornrity has bccn achievcd with lhis lcchniqrrc, nd tho rcsulting fabrics havc a mrrclr lcss wlxy fccl lharr fubricsnradc from conlinuous fi lamcnt P.'|,F.E. yarns of conrparablcrvcight.

'I'cxlurcd Ynms

Continuous fi lanrcnt P.T.F.E. yarns nray bc '-I-rrslan' tcxtrrrcd loprov idc a n rorc un i fo rnr , h igh ly porous yc t d i r r rcns ion t l l y s tab lcfabric having a dry, spun-yarn-typc handlc.

l lcat Setting

For service at modcratc tcmpcralurcs (100"C.), hctt scIing nltybc achicved by convcntional boil-oll. Furthcr exl)osurcs in boil irrgwater wil l cause very l itt lc additional shrinkagc. Considcrrblcadditional shrinkage of thc boiled-oft fabric nrry occrrr, lrowcvcr,if i t is subjcctcd lo scrvicc lclnpcr lrtrcs wcll ubovc thc boil-ollconditions.

STRUCTURE AND PROPI]IITIES

Firre Struclurc nnd Appcnrance

Thc carbon atonrs forming thc backbonc of thc p.-f.F.E.molecule are complctcly surrounded by fluorinc alonrs, wlriclract as a barricr that protccts the carbon chnin. p.' l ' .F.8. f ibrcsare extremely stablc to heat and chemicals.

The molcculcs of P.T.F.E. arc elcctrically nculral, ancl lhcrcare no strong polar forccs binding thc nrolcculcs togcthcr as iuthe casc of polyamidc, polycstcr, cellulosic and othcr f ibrcmolecules, Tlre molccules of P.-f.F.E. havc an cxlrcmcly rcgrrlarstructure, however, and this makcs possiblc a vcry closc packingof the chains. P.T.F.E. l ibrcs havc n high dcgrcc of crystall iniry-,and thc rclntivcly wcnk but vcry nunlcrous v;rn dcr. lVnlisforces combins lo crcnlc i l strbsllnlial inlcrnrolccular altrncliorrwithir the crystall i tcs.'fhc

nrolcculcs of I ' . ' f ,F.E. arc clsily dcforructl by grossnrcchnnical forccs. and lhc lrrrorphorrs zoncs of thc fibrc irc soft.

5 t 3

f_F'Jr.-FJJ'1'�1 f'�l f''i t F"i - - n r n r r r nr l

I

I

I I A N D B O O K O F T E X T I L D F I B R E S

By contrast, thc closc packing o[ thc largc fluorine atoms rouncllhc c rbon chairr ntakc thc nolccules rclativcly inrmobile toforccs o[ the order that producc Brownian movement. The linal( ransfornr ation, thcrefore, fronr an interlaced fibrous structureto a frecly-moving nrollcn nrass does not occur unli l quite highlevcls of thcrnral cnergy are reachccl.

P.f.[:.E. f ibre is thus solt and vcry l lcxible, and yet has ahigh nrelting point. Thc close packing oI 0uorine atorns around{he carbon and thc close fi[ ing of molcculcs jn thc crystall i tesare also rcsponsiblc lor thc high dcnsity of the fibre.

Filanrents are smooth surfaccd and of rorrnd cross-scctiorr.-l 'hcy are lan to brolvn i l colour, but can bc bleached white in

slrong oxidizing mincral acids.

'fctritcily

Monofilanrctt

cN/tex (g/cten)std. : 10.6-12.4 (1 .2-r .4) 4.4 (0.s)wcf : 10.6-t2.4 (1.2-t .4) 4.4 (0.5)S t d . L o o p : 9 . 7 - 1 1 . 5 ( 1 . 1 - 1 . 3 )s rd . Kno t : 9 .7 -1 .5 ( l . l - 1 . 3 )

t" t t t t ' "st t" t t* t l tkg/ .ul t 2,20s-2,62s

( lb/ in/) (3 1 ,500-37,s00)Elongalion

l5-32| 5-37

(per cent ) S td . :W e t :

980( 14,000)

5252

Initial Modulus

123.6 cNi tex ( 14 .0 g /dcn)

lYork of ltupturc

0 .12 g .cm. / den.cm.

Avcragc Stillness

Stap lc ; 132.5 cN/ tex (15 g /dcn)F i lanren t : 19 .4-62 .7 cN/ tex (2 .2 -7 .1 g /dcn)

Aycragc Touglulcss

0 .12-0 .15 .

5 1 4 5 1 5

N : S Y N T I T E T I C F I B R E S

Spccific Gravity

L l .

[,Iccl of Moisaure

P.T.F.E. clocs not :rbsorb trroisturc. Most non-wcttrblc of ir l lknown hbres.

'l hcrrnrl Propcrlics

P.T.F.E. has the bcst thernral stabil i ly ot thc tough, f lcxiblc fibrcs.Sonrc inorganic fibrcs, sLrch as glass or xsbcslos, ltxvc bcttcrthcrmal stabil i ly, but are not as tough or chcntical-rcsislirnt irsP.T.F.E.

On being heated, P.T.F.E. shrinks to son)c cxtcnl. l?abrics nraybc pre-shrunk by a b l ie f hca t - t rea lmcnt a t a tcn lpcra lu rc : rbovcllre proposcd servicc tcntpcrature,

P.' l ' ,F.E. f ibre loses i ls nbrc propcrtics an(l rcvct.ts to its nlirssivcform at 327"C. It retains a use{ul strcnglh ult to 205.C., irndfor ccrtain i lpplici lt ions can scrvc at tcnrpcr;tlrtrcs ;rs high lrs288'C. At 290'C., dccontposition products i lrc lost irt th; rrtco f 0 .0002 pcr ccn t per hour ; a t 430"C. , a t thc ra tc o f 1 .5 pcrccnt per lrour.

P.T.F.E. retains a good sct and abrasion rcsisluncc wlrcn ltca(cd,and can be r)scd elfectively for many applications :rt 20J.27.5.O.

Usclul Environmantal 7'cntpctature.,-73.C. lo 2?5"C.

Zero Strcngth Temperat re. 3lO"C,

C cl l crttpcruturc. 32'1'C,

S pcci f ic I I car. 0.25 Il.T.U./lb./ " F.

' l ' henna l Conduct iv i t y . t ; l B : t .u . lh r . / sq . f t . / . F . / in .

F latntnabi l i t y. Non-fl irmmablc; nrelts with ctcconrposition.

Eflcct of SuDligh(

Neg l ig ib lc .

I I A N D T ] O O K O F T B X T I L E F I B R E S

Chcnricnl I 'ropcrtics

Acitls

P.'f. l :.E.-fibrc is conrplctcly incrt, lor exanrplc to boil ing sulphuricacid, lo luming nitric acid or to aqua regia.

Alkalis

P.T.F.E. is conrplctcly incrt, cvcn to boil ing stturaled sodiunrhyd rox idc .

Cenersl

!.T.F-E. has an cxtraordinary rcsistance to chcnrical degradalion.On lhe one hand, the carbon-to-carbon boncls are

-extremelv

stro0g, thc ouly reagcnts that wil l break them being molte;alkali metals. On the other hand, the fluorinc atoms aie packedso closely around the carbon chain that the carbon_to-;arbonbonds in thc chain arc thoroughly protectcd from any reagcrltcxccpt luorine gas at high tcmpcrature and pressure, oi chloiinetri l luoride.

Elfcc( of Orgtnic Solvcnts

The only knorvir solvenls for P.T,F.E. are ccrtain perfluorinatcdorganic l iquids at tcmperatures above 299"C.

Inscets

Not attackcd.

Micro-orgaoisms

Not attacked.

Electrical Properlics

Exccllent insLrlator.

Arltcsivcncss

Fcw nraterials wil l stick to P.T.F.E.

Cocllicicna of Iiilrrc-to-Filrre Friction

About 0.2 - lowest of all known fibres.

5 1 6

l ' - i J -U L i L= ' L - l \ : ' L ' t ' L ' L ' $ l ' l ' l | l t l r l t l r\ L L \ \ \ I - \ -

S Y N T I I E T t C F I D N [ , S

F

z

-R# $rffi#*u

PolytetrunuoroetIIJIc c ("1'clo ')

P.T.F.E. FIBRES IN USE

P.T.F.E._ fibrcs are uniquc in that they conrbinc thc rcsistanccto chemicals, solvents and elcvatcd tcnipcratr,r"* nr.o"iot".i *iif.,inorganic nbres, with the flcxibility and torrghncss ftrat arc iypici,iof many organic fibrcs.

Front the oulsct, P.-l'.F.8. librcs havc bccn cxtrcnrcly costly,and for this_rcasorr ulonc lhcy coulcl rrot bc corrsidcrcd f.; g";;;,i itcx t i lc usc. In .addi t ion, t l lcy l lavc nn unplc tsant , grcasy i i rnd lc ,oo rnoisture absorption, high dcnsity and low nroilulus; cvcn iicost was not an important factor, thcy would bc of littlc intcrcstfor apparcl applications.

Thc outlct for P.'I.F.E. fibrcs must obviously lic in cncl-uscswhere performance is of greatcr signilicancc ihan initirl highcosl, and such cnd-uscs h vc crcalcd a rclalivcly snra

lrr-iiimportant nrarkct for p.T.F.E. fibrcs.

5t7

| | A N D D 0 0 K O F l E X l l l - E F I a R E S

'l'o,\icit y

Although l,.T.F.E. itsclt is not poisolous in ally way, it givcsolf toxic gascs when heated above 204'C. The release o[ thescgascs incre3scs as thc temperature rises. Care should be taken,therelore, when P.T.F.E. is being used to ensure that snrallportions of P.T.F.E. l ibre do not contaminate tobacco. A pieceof P.T.F.E. l int picked up by a cigarette could evolve poisonousvapours which might cause discomfort if inhaled. Srnoking shouldbc prohibited whenevcr P.T.F.E. f ibre is being processed.

Dnd.Uscs

Tltc rpplications fo; P.' l ' . t:.E. f ibres are alnrost entircly in the l ieldof iudustrial specialt ies, where there arc lnany small-volume usesfor a fibre that combines toughness with unprecedented corrosionrcsistance.

Draidcd I'ocking

l' �.T.F.E. braids arc uscd with grclt succcss in the packing o[chemical pump shafts, whcre the material nrust withstatd highlycorrosive materials. Irr a pump handling 102 pcr cent funtingnitric acid, for examplc, a braidcd packing o[ P.'I ' .F.E. I ibrc wassti l l in good condition afler T rnonths, whereas the best previouspacking lasted 2-3 weeks. The packing in a centrifugal pumphandling molten urea nrixture lastcd 34 days, whereas lhe bestprevious packing lasted 2 to 5 days.

The low coelTicient of friction of P.T.F.E. f ibre contributes toits success in this application. Best rcsults were obtained byinlpregnating the braid with P.T.F.E. dispersion.

Filtratiotr Fabrics

The high resistance to corrosion of P.T.F.E. Iabrics enables thernto serye as fi l tration fabrics for spccial industrial applications.P.T.F.E. is used successfully for.the fi l tration of hot, corrosivcliquids and gases o[ nrany types.

Gaskels, clc--l 'he

chenrical resistancc, softness and toughness of P.-f.F,E. f iblcrre charictcl ' istics which scrvc it wcll in thc production o[ gaskctsfor pipe flangcs handling corrosive l iquids. Othcr uses include

5 1 8 5 1 9

B: S Y N ' rT E ' I ' I C F I DRES

Iaundry. pads, launchy ro l l covcrs, spcc ia l convcyor bc l t inns.crcclncat tapcs and wral)s for corrosivc scrviccs, nrolccti-vccrothlng, corrosion-rcsistant cordagc, anti-stick bandigcs, andhose and V-belt curing tapes.

BearirtgsThe Iow coefllcient of friction and high load bcaring characlcris_tics of this fibrc havc rcsul(cd in its wiclc acccptiric" i"-i;;;duty bearings where low rclative spccus "r. i,;;;i;;

'8";;j;; '.

rnay be fabricated from wovcn fatrrics or conrpositc ,;"1;;;;j;containing P.T.F.E. fibre flock.

FLUORINdfED ETHYLENE.PROPYLENE COPOI-YMEI{FIBRES

Fibrcs spun fronr fluorinatcd ethylenc_propylcnc copolynrcr:

I

t l

t l

t lc - cI I

F.E.P. RESIN

INTRODUCTION

The introducrjon of p.T.F.E. plastics and fibrcs has bccn followcdoy the developmcnl. of many resins bascd uporr copolynrcrs o[tctrafluoroethylcne. Onc oI the most irnporlrnt of t l icsc'is ; c;-po lymcr o f l c t ra .0uoroc thy lcnc and hcxa l luoropropy i . , , " , * f , i . f i ixnown as ltuorinatcd ethylcnc propylcnc copolyrrrcr, or I:, l f.p,

l lures spun Irorn F.E.p. arc vcry similar to l ' ,1..F.E. f ibrcs-cxccpL lhat thc F.E.p. f ibrcs are thcrmoplastic, ."lt iug ot nlroui290" C.

I I A N D I } O O K O F ' T E X T I L E I I I I } I T E S

PITODUC'TION

F.E.P. r'csinsf iuoroethy lene

areaud

+ y iIlt i I l - ' t ,l ' - f - ' i l l ' - f - ' i / iI c : c l - > l - c - c - + cl r t l l r r l lL F F I L F F \ F

[r fl- l i : i ILF FI

prcducccl by the copolyrnerizationhexa llu oropropylene :

oI tetra-

TETRAFLUORO.E T H Y L E N E

P R OPt:I{ 'f IES

IIEXAFLUORO-PROPYLENE

F,E.P. RESIN

Sinrilar to P.'f.F.8., but thcabout 290'C.

Iibres are thermoplaslic, meltiug

POLWINYL I?LUORIDE FIBRES

Fibres spun fronr polyurcrs or copolymcrs of vinyl fluoricle:

CI I . = Cl lF - ) -Cl l^ -CI ' lF-Ct l^ -Cl lF-z 2 2

PRODUCTION

Polyvinyl fluoride nronofilaments are produced by extrusion ofpolymcr follorved by orientation.

S'TRUCTUIIE AND PROPEIITIES

Tbnocity 19 .4-38.8 cN/tcx (2.2-4.4 g/clen)

Tcttsilc Soengtlt 3,500-7,000 kg/crn2 (50,000-100,000 lb/in2)

lilongat iott l5 -30%

r u u L _ L ' L ' t ' [ t " L " 1 1 [ u . . l l u i l

It t i , t ia l , Modulks t0 ,500-38,500 kg/c r2 (150,000_550,000lD/r n . )

I,lsstic Propertics ljWo recover! up to l(y/oextensionRe lative Stiflrcss t76.6-397 .3 cN/tcx (20_45 g/dcrr)Rclative Touglnrcss 0.3-0.6 (est)

&;efiicient of Friction 0.1

Resistance to Abrasiort Vcry good

Relractivc Indcx | .42

Specilic Gravity | .7 6liflcct of Moisturc Surl'acc rcsists \vcttirrg arrtl tlocs not rctainwater. Adsorption 0_042o Shrinkagc in rvaier at l00oC. :rl.tcr idltinutes, 4-2A,/o

Tlrcrnul Propcrties

Mel t ing point : l?0oCUsr l ) le tcrnpcr i r t r r re ranec: -620 to l50oC.Loss of ter rs i lc s t rcngth i t lOOoC.:2g, /oLi fe at l50oC.: ur l i in i tec lF larr :nrabi l i ty : se l f -ext i l gu is l r ing a l ( l norr - t l r ipp i r rgSpeci f ic hear : 0 .33 cal /c loC.

-' l f rcr r l r f conduct iv i ty : 1 .9 x I 0 -4

ca l /scc/c l r r2/uC/cr l

Elfect of Sunlight Excellcnt rcsistanceCItcnt.ico.l lopenics Very good rcsistancc to nlost corunt()ncne| l ca ls . l (es is tant to ntost con)n lon ac ids,ox i r l l r t ts l r rd so lvcnts,except funring sulphuric acid, prinrrry aliphatic arnirrcs iriiSCetol le

Resistanca to Agcrirg I3xccllcnt

ht sect s : Micro { rgorrrtrrrs Exccllen t rcsistilncc

Elcctrical hoperties

Dic lect r ic constant :60 cyc l0 l cyc 106 cyc

8.4 8.0 6.6

521

IN N F. E F, FTFT}

Dissipat ion factor :

Dielectric strength(vol tYmi l ) 3 .18 mm

0.2 mm

Volume res is t iv i ty(ohrn.cn.)

0 .049 0 .018

2601280

2 x l}ra

0 . t 7

POLWINYL FLUORIDE FII]RES IN USE

Monofilament has been woven into filter cloths and installedin a number of pulp mills to take advantage of the excellentresistance to chlorine and chlorine dioxi(le. Filter cloths are usedin other corrosive environments at temperatures ranging from-620 to l50oC. Other appl icat ions inc luc le mist e l iminators,sure ica l sutures and e lect r ica l bra id.

522 523

D : S Y N T I I E T I C F I O I T E S

POLYVINYLIDENE DINI I ' ITILE I : I I }RES

Fibres spun lrom polymers or copotymcrs ot vinylidcne dinitrile:

CN CN CN

C:r."=c/ -, -cn,,_J_cu-_J_\ r l

CN CN CNVinyl idene Din i t r i lc polyv iny l idenc Din i r r . i tc

INTRODUCTION

;1qiffi'.;itilf n #,,"i:{*r- fi}, i:n[i* riq;r#i;;i*ll'r*j:{l+ "ltlixr*:,;1",1" ixiti: ;,:a":1' * :;il u*lr J ffiH. 'st ;i+'ii"ffi

'ft,it [:" ?i'.I

fllq:r"ffi [fftrh:r#H{t1,,"i:'"",,,ffi itTNOMENCLATURE

Federal Trade Comnisdon Dcfinition

hln:iUl,:i:i #t'.1"i,,,1'iilii,"'i,i:;""*, ff ,:"lX',],',ifl :

:"-,#*fttrii#i[txffi IrlnlS,*,*i,r,{#iIk::"iT:lt"T#,,Hltil::: i*:::.' lil,ttiit,{:,fil;

I I A N D B O O K O F T E X T I L E F I B I T E S

PRODUCTION

'l)arvan'is a copolynrcr of vinylidcne dinitrile and vinyl acetatemade by polyrnerization of a mixturc of thc two monomers. Thcpolymcr has the following empirical structure:

I.I FI I] CNl l-c--c-{-c-

l lH 0 t { c N

ICOI

CHIr{onourcr Synlhesis

Vitryl Acctarc. See prge .4(r3.

Vitt l ' l idr,tu 11,,t ' ,r 'r,' fhere

are several possible routcs to vinylidene dinitri le, includingthc fo l low ing :

(a) Malonitri le and formaldehyde are reacted to form tetra-cyanopropaoe (l). This is then heated to drivc off malonitri le andfolm vinylidene dinirri le (2).

MALONITRILE

VINYLIDENE MALONITRILEOINITRILE

Production of vinylidcne dinitri le from nralonitri le

524

C N C N. 1 ) l l

+ cH,o ' - - - - - j - : i -> H-C-CH"-C-H- t lCN CN

FORMALDEHYOE TETRACYANOPROPANE

Q) _-.-"

*-"'

C NI

2 H - C - H

IC N

CN CNt lC : C H . + C H "l lCN CN

' t I ' t I I ' t ' r l-1.*,-"

r r : s Y N T

E T t c I : l l t l t u s

. (b) Acetic anhydrirlc ancl hyrJrogcn cyrnidc arc rc:rclc(l to lornll.-acctoxy-1,' l -dicyanoc ianc

pvtolvsis results in vinytidcnc ,',r illli"'l:it]"""' oI rcclic acid bv

ACETICANHyDntDE H-YDROGEN t-^cEroxy-l , |-DICYANOET ANECYANIDE

C NI

lJcN ' > c l l j co cocl t .t -

C N

+ CHr COOH

AC E TICA C I D

cffectivcly rvith acidic so<liurn

525

cH.co.

f +cl{! co

C NI

- l

CN

VINYLIDENEDINITRILE

I)roduction of vinyl ir lerrc dinitr i lc frorD lcct ic lnhytl . i t lc

I 'olynrcriza{ion

A.nr ix ture.of v iny l idcnc d in i t r i le and v iny l i rcctatc in 50:50 nro lratio- is polynrcrizcd by hcaling a solution of thc two ,rr;;;,;;;;

1ffi n,;l',?:,X'il:"::,f,1; Xl,?i',u,",lll,llii,,,;li:,tlffilo(r and washed,

Spinning

The copolyrncr of vinyliclcnc dinilr i lc nd vinyl f lcctatc is:i::::i::.^ :,.9li.ln{, fornrarnirJc, "n,r rl,c,ol,iiiol, i;-;,;l;;,cjilll;"Jll :illH'$;,:i:,;iilf iJ "il'l:illi,::;:l;,1.?,'"1'",T;::cipi tatcd and lol srrctc lcd bcforc bcirr t ; r ; i ; ; j ; ; ; . i ; i ; i ; ;slaplc fibre.

PROCESSING

Blcaching'Darvan'

may bc bleuchccl

L f f t f n E E n n l t F F _ FI T , \ N D B O O K O F T E X T I L E F I B R E S

calcium hypocirloritc oi sodium chlori lc. Alkalinc hydrogenpcroxidc should not bc uscd.

Dyeing'Darvarr' can be dyed with disiperse, cationic or azoic dyes. Ithas l itt le or no all inity for direct, acid, metall ized, chrome orvat dyes.

Pastel shades are produced on'Darvan'by using disperse dye-stu[Is or combinations of disperse and cationic dyes. Mediun)and deep shades are obtained rvith disperse or calionic dves.Azoic dyes devcloped with p-oxynaphthoic acid are rrsed forL : lack , navy and some red shades.

i, ledium and deep shades require carrier or pressure dyeing.Vigorous afler-scouring is needed to renlove excess dyestu{Is andcarrier (if used).

Strong alkaline conditions, dry temperatures above 162"C., andwct Lemperatures above 120"C. should be avoidcd.

STRUCTURE ND PROPERTIES

liirre Slructure and Appcaratrce

Molccular SlructureVinylidene dinitrile will copolymerize with many monomers, andil tends to lorm alternating copolymcrs rather than randomcopolynrers. Thc structure of the copolymer with vinyl acetate,for example, is virtually the same no matter wbat proportionsof the two monomers are used. The monomer units ;lternateto form a polymer containing the two units in 50:50 molar ratio.In practice, the polymer is made from a mixture of monomersin this ratio.

The alternation of monomers in the polymer structure of'Darvan'is probably due to the strong electron-attracting forcesof the two nitrile groups on a single carbon atom. Hydrogenbonding results in strong intermolecular attraction betweenpolymer chains. This results in high second order transitiontemperatures in vinylidene dinitrile copolymers. The transilionlemperature for an equimolar copolyrner of vinylidene dinitrileand v iny l acctate is I7 l 'C. This is some l l0 .C. h i ther than fora comparlble copolymcr of acrylonitrilc and vinyi acetate.

526

B : S Y N T I I E - I ' I C F t A R E S

.X-ray dil lraction pa crns show an almost cornDlclc abscncco[. crystall inity in ,Darvirn'

f ibrc, with u.ry ,f igf, i ""i1""""'oioricntation. Thc fibrc thus has no l ' irst or<Jer traniit io,.I p;;;;;

- '

Fibrc Fornr'Darvan'

has a IIat, curled cross-scction. lt is slightly oll-whilc.

Tcnacity

Dry : l ' 1 .7 cN/ tex (2 .0 g /dcn)lYet : 15 .0 cN/ tcx ( I .7 g /den)

lensilc Slrcngth

2 ,100 g lcm2 (3 0 ,000 lb / in2)

Elongation

30 per ccnt, wet or dry.

Elaslic Recoycry

Fronr 3 pcr ccn l cx tcns ion : I00 pcr ccn t .I : ro r r r 5 pcr cc l l l cx tcns io l | : g5 pcr cc t | t .

Inil ial Modulus

l' l 6.6 -22Q.'1 cN/tex (20-25 g/dcn)

Yicld Point

S t ress : 6 .6 cN/ tex (0 .75 g /dcn)Strain : 2-3 per cent.

AYeragc Sailltress53.0 cN/tex (6 g/cten)

Avcrnge Toughncsg

0.3 .

Spccific Gravity

1 .2 .

ElTcca of Mois(ure

Regain: 2-3 pcr cent.After 3 nrinutes in watcr at 100.C., ,Darvan,

fabrics show a527

_:t

528


sh' inkage o[ I per ce ' t ; : r f tcr 30 nr inutes a[ I20"C. , they s l r r i 'kbctwecn I and 15 l ter ccnt .

I'hernral Properlics

Sof tening/mel t ing point : 170-176"C. Dimensional ly s table at150 "c .

ElJect ol fliglr Tcmperature

Af tcr 8 days 'dry hcat at - l65 'c . , test . sa. rp les of 'Darva ' ' rc ta incd

thei r or ig inal tcns i lc s t rengths a lnrost unchangcd. Al ter 4 days,clry _hcat at 180"C., the tensile strength was 70 per cent of t leoriginal.

Flamntabilitt' '

'Darvan' compares in ease of ignition ard rate of f lame travelwith untreated cotton, acetate and viscose rayon. .Darvan,fabr ics rnel t -burn. The apparent ign i t ion ter 'pcraturc is 4 i i .c .

Eflcct of AgeNil.

lillcct of Sunlight'-Darvan'has

a high resistarce to the e{fects o[ clirect sunlight.continuous l l lament yar's exposecl in Floricra for z+ monthsretained 88 per cent of their original strength.

Fabrics made from 'Darva'' staple fibre exposccr to Arizo'a

sun for 5 months su{lercd no measurable loss of strength, andretained over 85 per cent o[ their original strength in 36 months.

Chcnrical Propertics

Acids

Resistance to acids is good. After 4 hours in l0 per cent sulphuricacicl or nitric acid at 100"c., there is a loss of strength arnountingto 6-30 per cent.

Alkalis'Darvan' has a good resistance to dilute sodium hyctroxicle at lowtc,nperatures. After 168 hours in 0.5 per cent sodium hydroxideat 44"C.,'Darvan' suffers a loss of strength arnounting to 6-30per cent. The libre is degraded by heating for 4 hours in 5 perccnt sodium hydroxide at 75 'C.

N : S Y N T I T E T I C F I I ] I I , E S

G encrnl'Durvan'

has i i g.ood_ gcncral resista.cc to .tt lck rly chc'ric.rsln comlnol l use. ' I 'he f ibre shows no loss of s t rerrgth a i tcr 4 hoursin a l0 per cent z inc chlor idc solut ion at 100"C.

Dllect of Organic Solvcnls'Darvan'

is insoluble i ' aceto 'c and in rnct r ryrcnc crr ror idc, . rc lif

r l.ot a{Iected by the solvcnts usc<l gcncraliy jn dry .l;;;, i ;;;.I t dissolvcs at roo' rempcrature in tr i i rcthyr iui iunuiir. . ' -""" '" '

Insccls

Not attacked.

l\{icro-organisnrs

Not a t tacked.

Polyvinylidene Dinitrilc (,Darvai)

529

15 20 25(% euoNcarroul

lF,HFFr-- l-_l- l tT I N D B O O K O F T E X T I L E F I B R E S

POLYVINYLIDENE DINITRILE FIBRES IN USE

'Darvan'is unusual antong synthelic I ibres in the combination ofso f lness and les i l ience wh ich endows i t w i lh x r t ros t i l l l rac t ;vehandle. It is very l ike wool in this respect.

Mechanical Properties'Darvan'is a medium strength fibre, comparable with rayon, andit has good elastic rccovery. Fabrics are durable and longJasting,being cornparable with acrylic f ibres in their wearing properties.They havc good crease-retention and wriukle-resisting characteris-trcs.

Specilic G ravity

The specil ic gravity is lovr, a factor which contributes to thegood covering properties of 'Darvan' fabrics.

Moisture Relaionships

With a regain of 2-3 per cent, 'Darvau' is intertnedialc betweenthe hydrophobic l ibres, such as polyolcfins, and the more absor-ben[ f ibres such as nylon. Tbe accumulation of static electricitycould prove troublesonre.

Thernnl Properties

The softening temperature of 'Darvan'is on the low side, andcare is needed in processes involving elevated tcmperatures. Asafe ironing temperature of 160-175'C. is recommendcd.

Despite this low softening lemperature, 'Darvan' retains itsmechanical properties well at temperatures close to the softeningpolnt.

Flammability is comparable with that of cotton, rayon aodacetate.

E nv i rorutre rrt al C o trdi t io trs'Darvan' fabrics are rot-proof, insect-proof and resistant to sun-light. They wil l withstand exposure outdoors for long periodswitbout deterioration.

Chetnicol Resistance

Fabrics of'Darvan'are resistant to most of thc chemicals and

530 5 3 1

rF,TtA : S Y N T I I E T I C F I I ] R E S

solvents encountcrcd in normal usc, but thcir chcnrical rcsisllnccis not as high as that of fibrcs suclr as polyvinyl chloridc orpolycster types. 'Darvan' fabrics sbould not bc subjcctcd to Kicrboiling.

I'Iigh Bulk YurnsWhen fibre is crimp-set undcr stcanr pressurc, the crimp bccotucsmore permanent. Fibrcs in yarns spun fronr crimp-sct ,Darvan'appear to have lost thcir crimp, but a fcw minulcs in boilingwater, or even a few rveeks at room tclltpcraturc, will pcrmit thcfibres to revert to their crimped state, giving a lotty high.bulkyarn.

'Darvan' tow may be convcrted to bulky yarns by thc Turbo-Perlok system. The difierential shrinkagc attained is considcrablyless than that of the acrylics, but it is cnough to give a sorrrcwhatlofty yarn.

IIeqr Seui gFabr ics madc f ronr 'Darvan' n l t ty bc l lc i l t -sct .

Washing'Darvan' [ibre absorbs only a sn]all atnount of watcr, and fabricswash readily in water and dctcrgcnt. Dimcnsional stability isgood.

Dryitrg'Darvan ' fabr ics d ry qLr ick ly an t l cas i l y , d r ip -dry ing bc ingespecially cllective, Thcy ntay bc tunrblc dlicd al tctnpcratrrrcsup to 60'C.

IroDiDg

Fabrics have good wrinklc resistance, and do not gcncrally nccdironing. If this is considered ncccssary, 'synthetic' sc(ing slrouldbe uscd. Maxirnum safc ironing lcmpcrlturc is 160-l?5.C.

Dry Cleaoing

There are no difl icult ics inhcrcnt in thc dry clcrning of , l)arvan'

fabrics, as the fibrc is rcsistant to all cornlnon dry clcaningsolvents.

I I N D N O O K O F T E X T I L E F I B R E S

llnd-Uses'Darvan' conrbines exccllent haudle with rcsil icncc and excellcntresislancc to degradalion. Its uses are essentially those in whichthcsc characteristics are oI particular importancc.

Deep Pile Fabrics

P i lc fabr ics con l r in i r rg 100 per cent 'Darvan ' p i l c a rc so f t anc lrcs i l i cn t , w i t l l l i t t l c tcn( lcncy to n r l t . Thcy nr ry bc d ry c lca lcdellectively.

Suitings'Darlan'/rvool

worsted suitings have good wrinkle resislance,cxccllcnt crcasc rcl.cution, good durabil ity ancl exccllent pil l ingrcsistancc. Woollen typc fabrics bencfit fronr lhe soft luxurioushandle of Ihe 'Darvnn'.

Knittcd Goods100 pcr ccnt 'Darvan' crimp-set, high-bulk yarns arc usccl inwomcn's sweatcrs, which have a remarkably soft, wool-l ikchandle. Thcy are capablc of withstanding repeated nrachine wash.ings and dryings.

I } : S YN ' r I I ET I C F I I }RES

PO I-Y.Sf Y I.I, I.]NE I II I}IIES

Fibres sprrn fronr polynrers or copolynrc,rs of styrcnc:

I N]'RODUCTION

PRODUCTTON

Polystyrenc is onc ,:f thc Dtost iruporlunt synlhctic nlasticrrralcrr'aJs, .arrd lhc polynrcr is tvniltblc i,, l^rg" l,,,,ur;i i";- '" ilcr:lttvcly low cosl. -f l lc

t l lononlcr, slyrcnc, was rl iscovcrcd irrl8ll, arrcl irs polynrcr.iz_alion wls obscrvcd.r,n,rfy nfl"*urif i. i iwas no1 unti l the htc 1930s, howcvcr, lhat polystyrcnc lr..,uii. , i irra.,or lDtportancc as a pllrstic.

. I ' o lys ly rcDc nray t tc cx t r r r t l cc l to fo rn t n tono, i l i l n rc | r l s , l r rd t l rcscI.rvc bccn producctl ftrr sonrc ycurs for spccirrl izctl ,,r;;: _;,; i;-,,;U f t l S l l D r r s l l e s

- c H

I(\

- cH. -cH, - cHI

hI'olvstyrcnc

Monotrrcr SynlIesis

Sty rcnc

Styrcle.h produccd by rcaction of bcnzcnc tnrJ cthylcrrc, bolhor wntc t r may bc ob ta incd f ro rn coa l o r pc l ro lc l I |n , l i l hy lcnc , inaddition, is madc fronr alcohol.

533

- l

If ) r t r t l a

l l l t

532

' I - [ - ] - l - l - -1 - - l - - I - - r " - r

JJJJTI T TF Fl l

i' , r NDBooK oF TEXTILE Fr rJ r ( r . : s

l,olyDrcriznliotr

Styfene polymerizes rcadily to a transparenl, glass-like plastic.It wil l polymerize quickly on standing at room temperature, at]dtho proccss can bc accelerated with the help of heat and catalysts.

Polymcrization is commonly carried out jn solution, or simplyby allowing the l iquid itself to polymerize in the mass. Styreneis also polymerized as an emulsion, including the special formof emulsion technique called pearl polymerization. Tlris consistsof stirring the styrene with water and a dispcrsing agent in sucha way that thc styrene forms droplets about the size of a pinJread.These droplets polymerize to form litt le beads or pearls ofpolystyrene.

--cH - cHz-cH - cH2 ---

O OPOLYSTYREN E

Irtrusion

Monoli laments are made by extrusion of polystyrene throughheated dies, followed by several stagcs of drawing-

S'IRUCTURE AND PROPERTIES

Illolccular Structure

N,[onoli laments are extruded usually from 100 per cent poly-styrenc. The phenyl groups fornring the side chains on polystyrcnemolccules arc so large and bulky as to interfete with the close-packing of the long molecules. lt has long been assumed, there-Iore, that polystyrene could not be expected to provide strongfibres of the type spun from polymers capable of a high dcgreeot crystall inity.

'fhe deyelopmcnt of polymerization techniques in recen[ years,

horvcver, has made possible the production of isotactic poly-styreoes which are highly crystall ine and melt sharply at 218-220"C. (cI. isotactic polypropylencs, page 567).

' l 'hese polymcrscould becorne of commercial importancc in thc nbre neld.

C H : C H 2I

h,S T Y R E N E

( v r N Y L S E N z E N E )

534 535

F l}T-F}}}}}I } : S Y N T H E T I C F I D R D S

POLYSTYREND FIDRES IN U.SE

Polystyrene monoli lameflts are used largcly as brush bristlcs.

I I A N D B O O K O I ' T E X T I L E F I B R E S

4. POLYOLDTT|N tr tllDs

Fibrcs spun front polymers or copolyntcrs of olelin hydrocarbons,such as ethylenc and pr-opylerre:

CH":611"-* - CH3 - CH, - CH, _ CH- _Ethy lcnc polycthy lc le

C l'{., - Cl-l=CI-I"--: --Ct{.--CH-CFI"-CFI-t l

cH:' cl{rPolypropylenePropylene

INTR ODUCTION

ln conrnron rvith nrauy otltcr compounds conlaining a doublcboncl olcfins are caprble of uudcrgoing adclit ion poll,merization.Ethylcne and propylenc, for.cxanrplc, polynrcrizc is sliorvn nbovc.

Olefirs arc opcn-clrain unsatufatcd hydroctrbons, ancl poly-olefin lnolecules havc Ihe backbone conposcd of a succession ofcarbon ittonls rvhich is tvrrical of all vinyl-type polymers.'I 'he

table on pagc 538 lists somc ot the sinrpler olellns andthcir polynter slruclurcs.

-I 'hcsc are all alplra-olc{ins, io which thc

doublc bond lics between the first and seconrl carbon atonls. . l-herctnairring portion of thc ntonontcr rrrolccule forrrrs nenrlantgroups a t t t rc l t cd to the s idc o f thc po lynrer ch l in .

l 'olyisobutylcnc

Thc first olclin to bc polymerizcd successfully was isobutytene, asIong ago as 1873.

ct{,c

CI{"

l)olyisobu t ylcnc rvas obtaincd as a viscous l i<1uict, but it was notunti l thc l910s tbat uscfirl I incar polynrers of isobutylcnc wercnradc. A rubbcrlikc polyisobutylenc was nritrkctcd bt I.C. Far_ben indus t r ie A .C. in Ccrn t rny , nnder the t rac le name,Oppano l ' .

536

al.t -

tt

A : S Y N T I I E T I C F I I T R E S

I l l ta t l . cx -ce l l cn t c lcc t r i ca l p ropcr t i cs an( l l l ) ig l r rcs is luncc to rc idsar tc l a lk i r l i s .

Polyctbylcne

l,",ii:irilff :Lj,iJ,l:.",fl i:!{i.;,J:: 1t;" : "TJir'ti,1T,:, lf:liilliii:".r,',',',""i*1' Tj:i y":']"[llli!'i:eilr,], "'il',,1:ffii,",rdft.'.i:"ril:{*,lrt,}i*illliT;:;,l*;ltliilisuccessfully.

iinii1# r,r#l *lr#,# flri{il|t*.,;#{l::r#;;i",:i:ili:li"i:",,T,,:"i,:i;r"ry,"][;t".;l_il,tii*ill1lft

il;ffi ir*h:iiTf ri jrii,;+l:liiTrr,t:,ffi:, i:i, lj,:,i.'':;',,'1"'"t,lf ;"":tln".h *, ff ilfi'3"ff ".'":,:"l'i'u'I:l"iiil:cstabrished ; ;;,,1;;; ;"#;,lj�"ifr,illTiiii{f ,fi{"lilji;?::,:i $i,|":''lii:'iT,?j.,'lll.f ;,i; -r;."il];;l"ili iilll;ll'If '.?i',:,,,,;'#:,,:?,ll r,"#

fi .,.;l

f ,i::1,,'l'"",'n:iffi:;:"'J":lli:l;fij'1:]:,1,,'ff ,' | il.:I'i:.1,',,J;l;ll;s:xt:ff f [i':,1'"1ff f tiTllt"*i:ln:;t'fui",,,;I'olylrropylcDc

-i-,f ;#i:{,fi#i:{:,::,illl*r:};i j"",l'*i[ititi;:"lti,i,i:{ii'}:fi :l:'il"lTf ,:::"ilt"l.:f ";1,",,r"l,,;;il'::

537

I ' I ' l ' I - I ' l - [ r - - 1 F i

I I A N D B O O K O F T E X T I L E F I A R B S

-fhis change in tbc status of polyolefin fibres was brought about

by the successful development of polypropylene librcs, Thesclibres display a combination of propcrtics which can servc then')rvell in applications thal extend throughout the tcxti le f ield as awhole. ln addition, they are nrade from a cheap raw malerial,propylenc, whiclr is available in almost unlimited quantit ies fromthe pctroleum industry.

ALPIjA-OLEFINS AND THEIR POLY\,IERS

M O N O M E R POLYMER

)

{2j

ITHYIENI CH.-CH.

PRoPYLtI IE Ct l r=CHCH!

SUIEt l t - l CHr=CHCH2 CH,

PENTTN€-1 CHr=cH(cH?lc l r l

J-METl lYt-8UIt IE- l Cl t r=CttC (CH:) ,

. l - I IETHYL-Pt l i l l t t l t -1 CHr=C(CttrCH(CH!) ,

t J l

( { )

$ )

(6)

( 7 } STYRtN t Cha=Cl l - C6H5

-cH2- cH2- cttr- cHr-

-cH2- clt - cHr- cH -

c[" cfl.

-cHr- cH -cHr-cH -

cHrcltr cHrcH!

-cHr- cH - cHr- cH-

(cn,trcH3 (cHJ,citl-cf ir- cH - cH?-cH-

cH(cHJ, cH(cH,),

-cHr-cH -cl l , - cH -

cn,cr(cH,tr cH,cH(cfir)-cHr- cH -cf ir- cl t -

coH" coH"

538

B : S Y N T I I A T I C F I B R E S

mt.totiFI19

Sp.c l f l c Crnv l l l c r .hd t . l t tn r t t ih r . .

Pol:a.r -q-

I'oUctrvl.ie (brdrcrEd)

rob6l$yr.hc (u!.dr)

rolr"&ryl;n. (isot.cttc )

FotJbulen.-! (isolacuc)

r.ryrEnl€no-l (liotacllc)

roly-3-!ellul-brlc!c-l ( t3ol,!c|Ic )

Iory-4{clhyl-!e!tq.o-1 ( L.otacttc )

fory-lFn.tlvl-l-hexo. (rJo|actlc )

rory!lt!.n. (atlcUc)

rolFtyrcno (IlotacUc)

o.9I-0,91 l0?-l2l

o.95-O,9t ll0-rl0

o.n-o.n r6J-t?0

o,9 l2t- r lo

o.87 .lr-uo

o.9l l0o-ll?

o.8J 21tO-2rO

0,86 l0!

r.o{-r.05 tt-110

Irregulari t ies,_ such as branching o[ chains and cnd-groups of di l fcrcr)tcomposttton (whrch are morc inl lor lnnt t l rc lowcr t l tc rnearr rrrolccrr larweight) may- impair crystal l ini ty in a polynrcr. Sonrc of thcsc irrenular-rt les result in a melt ing point which is lowcr than thtt of thc i idcalpolynrer ' , and whicb is therefore less sharply dcf incd than l l tnl of Durcsubstances.of low rnolecular weight. This-gives r isc to a transi i ior iIegron, wl lrch bcgins whcn thc s rr l lcst and torc irrc[ultr crvst jr tsmclt, and.which attains i ts. upper l imit (which is oftcn r-norc shirply

:.',j lu[ Xi:i."" structurallv more pure polymers) whcn lhc Inr,:cst

0ther I'olyolclin liibres

The table above lists somc of thc crystall inc polymcrs whichmay be made from simple olefins, with their nrclt ing points aoddensities. For most texti le applications, it is ncccssary tirat n fibrcshould retain dimensional stabil ity on bcating to at lcast l0O"C.If the fibre is to be used in makiirg apparcl fabrics, it shoulcl bccapable of being ironed without softening, and this rcquircsstabil ity to much higher temperatures.

Several of the simple olefins melt at tempcraturcs high cnough

539

I I A N D t r O O K O F ' I ' E X T I L E T I B R E S

lo rv i r r ra | l t cor rs i r l c ta t ion fo r gencra l t cx t i l c usc . po lvoronv lcnc-poly-l-rncthyl butenc, poly-4 -rnc thyl_ I _pcn tc nc, n,i, i oofu_a_r le t t ry l - I -hcxenc a l l n rc l t above 165.C. , and cou ld be rcga ider i aspotentially uselul texti le f ibres.

.. l lclow this leflrpcri lturc region, t l)e range of applicatiou becornes

I ln l l t cd , and l ib rcs c i tn be used ou ly w l le re t l l cy do no t h vc lowithstand morc tban a modest rise in temperatJr" "b;;; ;;;;; iPo lyc thy lenc is the .on ly compara t ivc ly low_nre l t ing po fvo i .n i i i "oc..uscd conlmcrclally iu Iibre_productiou, and its rarrge of atrpli_cuuon ls tcntpcrl lure-resl ricted in this wav. Practical expericlcc lras slrown ttrat all ibe polyolelins mcltiutbelorv polypropylene are inadequate fronr tbc poi"t oi "i"*'o?rcxurc tlbrc production. And sorne o[ those nlelt ing above poly_propylene nray bc disregardecl because of the higli "o.t of'," '*nraterial; polynrers nade from them woultl tr" to l i t l-fr i""lto bc colnpctit ive,

I 'olypropylene itself is ccouornically the nrost attractive oI thcschigher-rnelting poiyolefins. Another polynrer wtricl, tras ionleur rder cor r r r re rc i l l sc ru t iny i s po ly4_r r re thy l - l -penten ; . i i i ;raw. ntrterral, 4 -mcth yl- I _pc|l tcoc, is poteutially avii lable at rcas-onxb le cos t , and in adcquatc q r ran t i i y .

. Un lo r tu r )a [e ly , ear ly s tud ics on th is po ly r l le r s l lowcd th i ] trls pllysrcal propcrties deteriorate more rapidly thaD anticioatcdat clcvatcd tempcraturcs. Wbcre polypropylene- fi bres retain sornc50-60 per ccnt of lheir room lcnpcrrture streDgth at I00.C., forcxanrple, l ibrcs spun from poly-4-mcthyl_ l1)c,rtJ,r" ."tuin ooty fOper cent.

. lt scen)s unlikcly, thcrcfore, that any oI thcsc sirnplc olefinswl

oller a serjous challengc to lhc chcap and rcadilv avrilablcpropylcnc as a ralv nlirtcrial for polyolclin nUr" pro,tu"fio,r. noiv_propylenc rs ure ooe polyntcr in [his class rn wltich thc outstarrclir icadvantagcs oI polyolefins as fibre-fonling ,n"t"riuf, ,r*V t"'r""i lized.

. ' l l r c

Ia rgc-sca lc cor r r r r re rc ia l p roc luc t io r r o l po lyo lc f i r r l . ib res inurc lo tesccaDlc lu t r r re w i l l p robab ly be cent rc ( l on two po lynrers .un ttre one lrand, we have polyel.hylcne which is being'producedln enormous quant i t y as a p las t i c : rnonof i la rnents spun i rom th ispolynler have bccorne established il nraly specializcd fiel<Js.

On the other hand, we have polypropylcne, wlticlr has becolnean .important rnan-made fibre rvith a wide range of texti le appli-cano l ls .

540

*L t L

, ' L

, ' L

' L

r ' LrF L

L' t l l 1' t

- l ]

' I 1 ' L ' ' L r ' L

- L ' t_ i - t - - l

-[wo typcs o[ [ibrc, polyethyleuc and polypropylcrrc, tlonrinllc

lhe polyolc{in fibre lield. As alrca<Iy inclicatcrj, poiycthytcnc fibrcsirrc. of rclatively ninor irnportancc, scrving in spcciaiizctl appti-cations;.polypropylcnc fibres, on thc othcr lrarrd, arc of rriiclrgreatcr sigtril icance in the tcxtile field.

NOMENCLATUITE

o: s Y NT

l i . l . I C l : t t l l tDS' r ' ) ' t , t .s ( ) t ; poLt ,ot_t i l . tN t ; l t l t {E

CH,:Cll.,

INTRODUCTION

Faderul 7'rada Corrrtrrissiorr Dclinitiotr'fhe gcneric tern olcfin was cstablishctl by thc U.S. Fc<lcml

.l-radcConrrnission for f ibres bascd on polyolcfi irs. ' l 'hc

oll ici l l r lefinil iorris as follows:

Olefin. A nranuflcturcd tibrc in which thc l ibrc-l.ornring sub-stance is any long-chain synthctic polynlcr composcd of at lcast85 pcr ccnt by weight of elhylcnc, propylcrrc or otlrcr olc(in units,exccpt amorphous (noncrysll l l ine) polyolcfins qLralifying undcicategory ( I ) o I I)aragraph (j) of lt.u le 7.

NotcIn the se:tion that follows, t lre two cor))rrrcrci l ly-irvailublc t1,pcsot polyolclin fibrc arc discusscd individually:

l. polycthylenc Fibrcs.2. Polypropylcnc Fibrcs.

(t) PoLYETIiYLENE I:llllrts

Fibres spun from polymcrs or copolymcrs of cthylcnc:

(a) lI i gh-t e t n pc ru t urc Process' fhc

po lynrc r iza t ion o f c thy lcnc wus l rch icvcc l r l r r r . inc t l rc c r l v1930s by chenr is ls in I rnpcr i l l Chcnr ica l I ldus t r i cs L t t i . , t jns lan j ,

541


and a patent covcring tlre proccss was applied for in 1936(8 .P.471,590) .

The corditions used in this polymerization process were un-usually sevcre. Pressures of 1,000-2,000 atmospheres and tempera-tures of 150-200"C. were required, and the process was activatedby traces of oxygen. The product was a solid resembling parafl inwax.

'fhc industrial dcvclopment of clhylcne polymcrization pre-

scntcd nrany difl icult ies, but by 1939 polyethylene was commer-cially available in the U.K. Licences were granted by l.C.I. Ltd.to du l,ont and Bakelite (a division of Union Carbide) in the U.S.

I'olyctbylene's combination of cxccllcnt. dielectric and mechani-cal properties madc it invaluablc as an insulating material. DuringWorld War l l, the cntire outpul was used in higb-.trequency radarcquipmcnt, subrtrarine cables and other esscnlial applications. Pro-duction was expanded continually to mcet thc growiDg wartimenecds.

At the end of the war, new applications for polyethylene wereIound, not only in the electrical insulation field but in the produc-tion o[ f i lms, shcct, tubiog, extrudcd and moulded products. Poly-ethylene bccalnc one oI tbe n'lost i luportaut of the post-war plas-tics, and production has increascd steadily in recent yea$.

Polyrnerization of ethylene by thc high-pressure/high tempera-turc process does not result in straightforward l inear moleculesof polyethylene. Thc ntoleculcs are branched, and polymer pro-duced by this method may have as many as 30 brauchesfor every 1,000 carbon atoms in the nrolccular chain.

Ilranching restricts the abil ity of polymer moleculcs to packtogcther, and prcvcnts them aligning themselves into the orderlypatterns that make for regions of crystall inity, Polyethylcne nradcby high-tempcrature/high pressure polymerization is not bighly-crystall ine material, and this is reflected in its properties, especi-ally with respect to the characteristics of f i laments spun from it.The melting point of polyethylene made by this process, forcxanrplc, is co,r]paratively low-about I l0-120'C,

(b) Lo w-t e nr p e rct urc P rocesses

In 1954, Professor Karl Ziegler of thc Max Planck Jnstitule inGermany discovered a new techniqie for the polymerization ofethylene, using organo-metall ic catalysts (Belg. Pat. 533,362).

542 543

r l : s Y N - t . l t u . r t c I : t n R E S

liinri l i l I proccsscs wcrc dcvclopcrl by thc l, lr i l l ips l)ctrolcrnr Corrr-ii ' lf 1!,:lg. Pat. 530,617) a d by Srrndard Oit Co. (U.S. i, r.2,69 |,647) in rhe U.S.A..

- f l resc ncw proccsscs br ing about thc po lynrc r iza l ion o f c lhv_

lcnc at nlucll lowcr prcssurcs, and irl tcnlpcrtlurcs bclotv 100"C-Undcr lhese conditions, the nrolccullrr clt lt irrs arcvIurJr Lutssc conolt lons, tne nrolcct.t l i t r cl l i t ins trc t t t t tclr lcssbranched than lhosc produccd by thc hiSh-lcnrpcraturc/high_prcssurc- proccsscs. Zicglcr-typc polycthylcnc, for- cxatnplc, irussorne 4-5 branchcs pcr 1,000 carbon atonrs in thc nrolccultr citain:Phillips-type polyethylene has fcwcr than 2.5 sidc trunctl"s ;r.i1,000 carbon atoms. Thc high-tcmperaturc process, by contrist,produces a polyethylcnc with 25-30 sidc briinchcs pcr't,000 crr-'DOl l Alot1ts.

. ln

-add i t ion to p rov id ing po l l , rnc rs i r r wh ich thc r r ro lcc r r l csnave tewcr brancl)cs, thcsc low_tct)lpcratltr.c proccsscs yiclt l poly-nrcrs oI highcr molccular wcight.

. Tlrc ntolcculcs of polynrcr lrot)r low-lco]pcrilturc polynrcriz.n_Iron ploccsscs, with fcrvcr sidc br.anchcs. arc ablc lo pick tolcthcrrrrorc cflcctivcly thar thosc frorn thc high_tcrnp"r"tur" pr*"ir.t i i i"low-tcmpcrarurc polymcrs arc morc highly ciystall inc' th;;i i l ;;rnade by high-ternpenture polymcrizl rioir, "i<t rtris ntt"cts it icphysrca t . p ropcr l l cs o f thc po lymcr . ' f l r c

dcns i ty o f low_ lc r r rpcra_rurc po ly tncr , lo r exa l | lp le , i s h igher t l )an l l l a t o f t t )c h igh-tcmpcra lu rc fo lynrc r ; thc Iong unbranchcd nro lccu lcs o f ihcIo rmcr can pack c loser togc l l l c r , so t l l t t l l c wc ig l t t Dcr Un i tvorurnc ts tncreascd. Z icc lc r_ tvne po lyc thy lc r rc has n dcns i ty o f0 .95 , a r rd P l : i l t i ps - typc po tycr t i y tcnc o f O.OC.

. f t , " i " " , i , l ' " i , f , "

c i ln re r rypc o t po tyc thy lene is 0 .92 .

..-l-his dilTercnce in dcnsity is comrnonly uscd in rcferring lo l l tcdr t te rcn t to rms o f po lymcr . po lye thy lcnc nr : rde by th ; h iAh_tcfn pera t urc / high-prcssurc (carlicr) proccss is c lc<l

'Low-dcn.ii t v

I. ' ,o lyct hylenci polyntcr ma(lc by thc low-tcrrrpcrirturc/lorv prcssrrrc{fater)-proccsses is callerl //rglr-rlcasity l,olycthyl( c.

By 1956. h igh-der rs i ty po lyc thy lcnc was comnrcrc ia l l v ava i lab lc .I t was bc ing .pro ! t rccd no t on ly by thc Z icg lc r and I ' i r i l l i ps p r .o -ccsscs, Dut also by a modification o[ thc origirrl l I.C.l, nroicss,The

. incrcascd

- degrcc of crystalt inity and tlrc highcr rrrolcctLlai\r 'ergnt allectcd thc propcrtics of lhc polynrcr in ways rvhich cx_tcnded. its range ofpractical applications. Thc mclting poini, fo|-examplc , rvas now h ighcr : I30- l3g"C. comparcd w i r t r l iO_tZb.C.for lhc low-dcnsity polyethylcnc.

I I A N D I } O O K O F T E X T I L E F I D R D S

l, ibrcs fronr l ,os. l)cnsi ly Pol j ' l rcr

When supplies of polyethylcne became avai lable for general usejn t lre latc 1940s, the successful developnent o[ nylon hud alreadyslimulated ,ntercst in the possibil i ty of producing other types ofsynthctic nbrC. lvluclr had been learncd about tlrc spinning offinc fi l lmcnts by extrusion o[ molteu polynrcrs at high tempcra-tures. lt was natural, thcreforc, thrt the newly-availablc syntheticpolynrcr, polycthylcuc, should bc considercd ls ir sourcc oI syn-thctic f ibrcs.'I 'he 'clcan' shapc oI l incar polycthylenc ntolcculcs suggestslhat thcy arc capable oI packing together into the orderly arrange-nrents thfl l result in regious of crystall inity. Extru.lcd l i lamenlsoI polycthylene might be expectcd to lorm slroug Iibres whenslretched to orienlate the molecules.

Unlortunatcly, polyrnerization of etlrylene at high ten)peratureaod pressurc does nol produce straightforward l incar moleculesof poll,cthylenc. -I 'hc

cxtcnt of branching is such as to prcvcnt thcntoleculcs packiug togcther jnto the ordered pat.terns that makcfor a high degrce of crystall irrity.

Despite the low degree of crystall inity of this type of poly-cthylene, and the conrparativcly low molecular weight, the poly-nrcr can be extruded and drawn to form fi larnents of moderatcstrcngth. The early post-war polyethylcue was spun into com-!)aralivcly tbick monofilamcnts which fouud their way into anumbcr of practical applications. But the tcnacity of the materialwas too low to allow of the production of f i larnents fine enoughfor general texti le use,-l-hese

early fi laments of low-density polyethylene had manyinteresting properlics. They were chemically inert, and rvcre quileunaflccted by water. They wcre l lcxible and resil ient, and rvercnot attacked by nricro-orgauisnts or insccts. 1'heir gcneral charac-teristics were such as to encourage further dcvelopment by pion-eering firns. Hcavy spun-dyed li lamcnts wcrc woven into fabricswhich were tcstcd cxpcrintcntally in a numbcr of applications, in-cluding cnr-seat covers and furnishing nratcrials.

Thc early polyethylcne fabrics sullercd, however. fronr seriousshortcoolings. Dinrcnsional stabil ity was poor and abrlsionrcsislance Iow; thc fi laments deteriorated rapidly in sunlight; thcsoftening point was too low for normal texti lc use. It soon becarneclear lhat fabrics ntade from thc early low-density polycthylcncswcre not going to bc a conrmcrcial success.

544

r-i r lI

' l ' l ' [ ' l ' l t l ' t ' I ' l - I r - I

A : S Y N ' I ' I I E 1 I C I : I T R l : S

_Dcspitc thcsc sctbacks, a fcw lirnts corrtinucd thcir dcvcloprncnto[ polyelhylcne [ibrcs, nolably I.C.l. Ltd. and Courtflulds i((1. i;the U.K., arrd Rcevcs Dros. lnc. tnd Nxtion l l) lastics I 'roductsConrpauy in tlrc U.S.A.'fhcir cflorts brought a stcatly inrprovc-nrcnt jn thc quality of f ibre produccd fr.onr thc poiynl"i th"n vailable. But-rcil l progrcss wits lo conrc cvcntuii l ly'frorn thc( lcvc lopr r rc l ts in po lynrc r iza l ion tcchn iq r rc t l t t t l c t l io lhc r r ro_( luc t ion o I h igh-dcns i ty po lyc t l ry lcncs .

liibrcs front lliSh.Dcnsity I'olylncrBy I956, .h igh-dcns i ty po lyc thy lcnc was conr r r rc rc i l l l y ava i l : rb lc :r t was be ing produccd no t on ly by l l r c Z icg lc r anr j t ' h i l l i ns n ro-cesses, but by a l)odil ici lt ion of thc original I.C.l. proccss ioo...

-l 'his.nerv type o[ polynrcr madc possiblc thc spiirning of nruclr

[ inc r f i l an tcn ts l l ran thosc ob t i r inab lc f ro rn low-dcDs i lv ;o lvc t t rv i_cire. ns rnticipiltctl, thc rcducctl dcgrcc of ruolccular Lrlrnctri i ,gancl t lrc.highcr molcctrlar rvcighls o[ thc ncw polynrcrs brorrgli ircnnrkable inlprovcmcnts in thc physical prop"it i"s of thc tibics.I-t igh-dcnsity polyethylcnc fibrcs wcrc strongcr lhan lhc lorv-dcnsity types; thcy rcachcd tcnacitics conrpiirablc with lh t ofnylon. . ' Ihe soltening rangc was highcr; I30-1j8.C., conrprrctlwith l l0-120'C. for lhe low-dcnsity fibrcs. .fhc

sti l lncss ;f t l ,afibres had increascd.

. . Dcspitc thesc. and rclatcd improvcnrcnts in physical propcrtics,

nrgn-oensrty potycthytcnc rclaincd dclicicncics whiclt havc contin_ucd lo rcstrict jts developmcnt as a tcxti lc f ibrc. Filanlcnls spuDfronr it havc low rcsil icncc, an<I arc srrbjcct to rclativcty high'<ic-formation Indcr strcss (crccp).'fhe soflcning Doint is sti l l t; l ;;to nteet lhe rcquircnrcnls oI nornral tcxti lc usc. -fhc

ti lan)cnls lcndto spli l. Icnglhwisc, cirusing Practictl tt i l l icult ics irr proccssirrl.

_nddcd to thcsc shor tcor r r i r rgs l rc o lhcrs inhcrcn i in t l t c io lv_olcfin struclurc. I-hc lack of any afl inity for w tcr, tor cxanrplc,precludcs dycing by norntal lcchnrqucs.

1'YPES OF POLYEI'I.I Y[,IJNI! FIBRE

l

l,olycthylcnc is corrrrnonly procluccd toclay by onc or otlrcr o[ thct rvo

.polyn)erizat ion proccsscs ottt l ined Irovc, thc polyrrrcrs dil lcr-ing in density ancl othcr physical charrctcristics ticpcnding upontlrc process uscd.

545

t|-fTJ-NT F NIETTTI I N D B O O K O F ' t E X T I L E

F I a R E S i' I 'hc

two fonns o[ polyctlrylcnc utadc availablc in this way arcdcscribcd as

(a) Low-density Polyethyleue,(b) High-density Polycthylcnc.

l loth l.ypcs of polyelhylene nray be spun into ntonoli lamenls,and it is in this lorm that the bulk of polyethylcne libre is pro-duccd. Sonre hcavy denicr mull i( i lament yurns are also availablc,aud fiuer denier multif i lament yarus are spun in small amounts.

Polyethylcne monofihments arc available in a range of dia-metels and spun-dycd colours. They are produced norrnally inround cross-section, but nlay be exlruded also in l lat, oval andothcr cross-sections to rlreet spccial lequircnelrts.

NOMENCLATU RE

O lc litPolyethylcne fibres alc defined as o/cfrs under thc U.S. FedcralTrade Conrnrission dcfinit ion (sce page xxvi).

I'olyolelin

Ethylene is chernically a menrber of the olclin class of hydro-carbons, ancl polyethylcne is a polyolcfin. Polyetbylene fibres arethus a type of polyolefin fibre.

Poll ' thene

Thc term polyethylene is often uscd in the shortencd f.orm, poly-tlrcne and polyethyleue fibres are son]ctimes called. polythenefibres.

PJTODUCTION

IUonomcr Synthcsis

lirhylane

Ethylene is oblaincd from petroleunr processing.

546 547

B : S Y N T } I E T I C F I D R A S

l'olyr l lcr iza(ion

(a) I{igh Pressurc I ltigh Tentpcratura process

Ethylcnc is -polymerizccl by hcating at tcrnpcraturcs in thc rcgion

of 150-200'C., and prcssurcs of t,000-2,000 atnrosphcrcs. ;I.hcrcaction is pfomotcd by traces of oxygen or othcr cati lysfs. poly_ethylene is proclucecl in thc fornr o[ a mollcn nratciitt whichsolidif ies lo a waxy solicl.

(lt) Lotv PrcsstrclLov 7-cnperaturc process

Ethylcne is polyrncrizcd at ntuch lowcr prcssurcs and {rt tctnpcrl-lu res be low 100 'C. A var ic ty o f ca t i l l ys t sys tcn ts n ray bc uscc l .I l re p roccss dcvc lopcd by Pro fcssor Kar l Z icg lc r i r r l95 l_54 nradct rsc o f .o rganornc t l l l i c conrpouuds, c .g . o f l i th i t r r r r , sor l i r r rn t r rdi r lu rn rnrun l , t | l co junc l io t r rv i t l t a sn ta l l a tnou | l t o f l rans i t ionnretal contpound, e.g. t ita|l ium tctrachloridc.

Spirrling

(l) Low-dcnsity Polycr hylutc FihrcsI -ow-dcns i ty po lye thy lcnc is cx t rudcd iD to n ronof i lanrcn ls o f roundf la t o r o t l le - r c ross-scc t ions , us ing cx l rus ion tcchn iqucs , iu , i lu i iothosc uscd in nraking morrofi lanrcDls o[ othcr thcrrtroplaslic poly_In . rs , c .g . ny lon , saran , c lc ,

Mo l tcn po lyc thy lenc is hc ld , fo r cxanrp lc , a t about 205"C. , andcx l rudcd t l l ro l rgh d ics o f appropr in tc shnpc . F ihn tc r r ts c r r rc rg ingIronr the dic arc coolcd lo I5-60"C., ln(l i trc t l lcn p,,ss"r'_t roi,nJa set of oricnting rolls which draw tl)ct].I to bctwc;n 4 lrnd l0t i r rcs . thc i r o r ig ina l l cng th . Thc < . l raw r l io dcpcnds upon t l , " t y f "o[ polyrncr uscd.

Tho oricntcd monofilarnents arc collcctcd on st)ools or tubcs.

(2) Itigh<lensity Polycthylcnc Fibresl - l igh dcns i ty po lyc thy lcnc is cx l rudcd in to r r rono l i la r r rcn ls us i r r ttcchliqucs similar lo those uscd for thc low-<lcnsity polymcr. . l h!cxt.rusron tcrnpcraturc is prclcrably abotrt 210.C,

Drawing o f thc ex t rudcd monof i l ln rcn ls i s cnr r i c ( l ou t a t nhigher tcmpcraturc. 'fhc

fi lanrcnts arc hcntcd by hot wirtcr, stc nlor hot air to 100-125"C.. ancl arc thcn passcd rouucl hcatcd rollsa t l l5 - l l0 "C. Thcy arc ( l t .awn to a h ighcr dcgrcc th r r r thc low-

I I A N D B O O K O F T E X T I L E F I N R E S

( lcns i ty l ' i l ancn ts , cor r r rnon ly in lhc ra t io o f l0 : l . l :hc l cn tper i r l l t r co f the c l rawing is c r i l i c : r l , rnd is l rc ld w i th in c losc l im i ts .

PITOCESSING

D-r'cing

I'olycthylcnc fibrcs cannot bc dycd cflcctivcly by rrornral dycingtcchrriqucs. Colourcd Ii lanrcnls :rrc produccd by dispcrsing pig-r'ncnts in thc ntollcn polymcr bcfore extrttsion, and a ratrgc oIthcsc spun-dyqd fi lanrents is available.

STRUCTURE N ND PROPEIITIES

'l 'he nrolccules of polyclhylcne are conrmonly branchcd, lhe

dcgrcc o[ branching dcpcnding uporr thc contlit ions unclcr whicltthe ethylcne polynrcrization takes placc. -f ltc polymcrization tcch-niquc also influcnccs lhe average molecular weight and the nrole-cular rvcight distribution of the polymer. Polymerization can becontrollcd to provicle a 'tailor-nrade' polymer with spccifiedllrarrching and rnolccular wcight charactcristics.

' l-hc nature of polyethylcne in these respects has an important

in0ucrrcc on lhe mechanical properties of f ibres spun from it.Decreasc irr the degrce of branching, ancl incrcasc in nolecularrveight, rcsult in increased tcnsilc strcngth and stif lness, and highcrsoltcning point.

'fhc physical properties o[ thc fibre are also influenced by thcconditions under which i i is spun antl stretched. As thc dcgrceof oricDtalion iDcrcascs, for examplc, so does the tcnsile strengthincreasc and the clongation at brcak dccrease,

Thc subsequcnt treatmcnl. of the orientcd fibrc is important too.Hcat treatnrcnt at tcnrpcraturcs below the softening point wil linfltrencc lhc flcxural strcnglh, clastic recovery and shrinkage.

Thc propcrties of polyethylcDc librcs are thus subjcct to grcatvariation, depcnding upon lhc avcrage molccular weighl, the size(lislribution of the molccules, the degrcc of branching, and thcway irr rvhich the oricntation of the moleculcs is controllcd. ' l 'hc

nrcchanical propcrlics o[ a polyethylene fibre produced by oncnrilnu[lcturcr nr:ry dil lcr consiclcrrbly frorr] t lrosc of f iblc pro-duccd by auothcr nranufacturcr. But dcspilc thcsc cli l lcrcnccs,

548

-]J-L-L--L- L. L-L'1_- L Ll'

B : S Y N T I I E T I C F I I I R E S

thc f i rc t lha t bo l l l l i b rcs a rc po lyc thy lcncs w i l l con f inc t l l csc var i i l -t ions w i th in rccogn izab lc I in r i t s .

Lo rrt -d c tt.ri I y I'o I y c t lry | cn eI'olycthylcnc prodtrccd by thc h igh-prcssurc / h iglr-tcnr pcra tu rcproccss rrray havc rs ntany as 30 branchcs for cvcry 1,000 carbonalonrs iu thc ntolccular chain.

I I i glr- D c nsi t y Polyct hyl c ttc

Polyethylcne p:oduccd by thc low-prcssrrrc/low tcn)pcraturc pro-ccss has fcwer branchcs in thc nrolcculc. T-icglcr-typc polyethylcncfor cxrrnplc. has sontc 4-5 branchcs pcr t,000 ctrbon irtonts in tl)cn to lccu l r r cha in l Ph i l l i ps - type po lyc thy lcnc has fewcr than 2 .5side branclres pcr 1,000 carbon atonrs.

The polynrers produccd by lhcsc proccsscs lrc of highcr nrolc-crrl;rrwcight thitn tl losc ploduccrl by l lrc highlrlcssurc proccss.

7 . O

6 . 0

^ 5 . O

e 4 ' o

u 3 '0F

cN/tex

62H I G H

ORIE NTATION

? .o

I O

M T DIUMORIE NTATION

STARTINGORIENTATTON

o l o ? o 3 0 4 0 5 0srnarl (g elorcerron)

I 'ol 1'cthl, lcnc ( l I igh Dcnsit! ' l ' ) ' pc)

549

i l " 1 f l l ' ' i F l F .EEEt t t - | : l " i l " i l ' l f " i l ' ' i t tT I A N D B O O K O F T E X T I L E F I B R E S

Fine S{ructurc i t |d Appclfarrcc

Polyethylene f ibrcs are spun commonly irr round cross-sccl ion,but may be produccd in olher cross-sections for special appl ica-t ions. The f ibres are smooth-surfaced and of waxy appearance.

Tcnsi lc Slrct lglh

The branched molecules of low-density polyethylene do not per-nri t of thc high degree of crystal l iui ty and orientat ior that is pos-sible with linear molecules of high-density polymcr. The tensilestrength of lorv density polyethylene monofilamerts is low; tena-c i ty around 8.8-13.2 cN/ tex (1.0-1.5 g/den) . L inear poly-e lhy lene monof i lamcnts, on t l re othcr hand, may be lhrce or fourtinles as strong, and are conrparablc in this respect with nylon.Tensile strength is 2.,100-5,950 kg/cm2 (30,000-85,000 lb/in2);tenacities are 70 cN/tcx (8 g/den) or more.

Exanrples o[ the tenacities o[ various grades of polyethylenenronofilamcnt are shown in tlre table on page 551.

ro 20 30 40s rRArN (% ELoN6ATToN)

I'ol 1'ct h1|etrc (Lote Dcnsity 7' ), lc)

550

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S Y N ' I ' I I E T I C I i I D N E S

rl.,,

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Ijlongalion

The elongation at brcak of low-densil.y polyethylcne monoli la-nrents n)ly be as high as 50 per cent. The more highly orientatedlincar polyethylenc monoll lamen(s, on thc other hand, may baveelongations at break of olly l0 per ccrt (sec table, page 551).

Mastic I 'ropc((ics

Polycthylene fi lanrents generally are l lcxible and rcsil icnt, thelow-dcusity nraterial being nrore flcxible than the high-dcnsitytype. lncrcascd orienlation results in increascd sti l lness (see table,page 551) .

Creep Characteristics

Polyethylcnc fibres tcud to undcrgo crcep when sub.icctcd to apcrsistcnt load ovcr long pcriods of t inrc.

' fhc dcgrcc o[ crcep

incrcascs with dccrcasc irr chain-branching, thc no[-rscovcrablcelongation being nrore pronounccd in thc high-density polymcrthan in thc low-density polynrer.

'fhe Phil l ips-type polyethylene, with less lhan 2.5 side branchcs

to cvcry 1,000 carbon atoms in tl le chain, has the worst crccppropertics. Ziegler-type polycthylene, with 4-5 side branches per1,000 carbon aton)s is bcttcr. And low-dcnsity polycthylene, withperhaps 20-30 branches pcr I,000 carbon atonls, shows tbe lowestr l c o r e c a l n r n c n n f r l l

Speci l ic Gravi ly

The specific grrvity incrcascs as rnolecules nre able to pack morecloscly togethcr. Lorv-density polycthylenc rrronofilamcnis havcspecific gravitics in the rcgion of 0.92; highly+rysiallinc high-density (lincar) polycthylcnc has a spccific gravity of 0.95 to 0.96(see table, page 551).

l i lTccl o[ Mois(trr- fhc

n ro is tu rc rbsorp l ion o f po lyc thy lcnc is v i r tun l l y r r i l , rndfor nrost practical purposcs can be regardcd as such. Dry andwct strcngths are identical, an<l nroisture has no elTcct on thcother rlrcchaIical propcrtics of the fibre.lydtcr Absorptio (ASTM 'l-csl

Method D570-541-): 0.01 per ccnt.

552

I I-t-L}-ut-I r u I | t t ' t t | r r I r I

L L L L L \ . E I T

I ] : s Y N I t | t s r ' l c r J t U ]' l hcrrtlxl I 'r()Icrl ics

Soltenirtg Point

The sofl.ening poirrt oI polycthylcnc r.ises ns tl lc (tcgrcc of crysll l .l inity increases. A low-dcnsity oricntalcd fi lamcnt o[ low nrolccu-lar weight wil l soften in thc rangc 85 96'C., whcrcrs a higlr-dcnsify oricntatcd fi lanrcnt wil l soltcn in thc rirDgc 126-132"C.(scc tablc, pagc 551).

ElJect ol Low T'unltcn urcPolycthylcne rctains its f lcxibil i ty to vcry Iow tcnrpcralurcs; it isoutstanding in this rcspect.

I] l i tt lcness tempcrature (ASfM -Icst [4erhod D746-55.f) is

l c s s t h a n - l t 4 ' C .

lilJatt ol IIigh l'(t perutrrtc

l 'olyclhylcnc rlocs not dcgrldc r.crdily on lrclt ing. With thc hclpof stabil izcrs, it nlty bc hculcd for shor.t pcriotls up to j l5"C].w i lhout dcconrpos ing or yc l low ing . ' l ' l l i s l l c t s t b i l i t y r | l kcs r r rc l t -cxtrusion of thc polynrcr a prrctici l l proposition,

Shrinkagc Propcrties

Polycthylcnc fibrcs do not show irny rpprccilrblc incrcirsc inclystall inity ou hcating bclow tlrc softcniug point, and pcrnraDcnthcat-sclt ing does not takc placc. Sonre dcgrcc of hcat-sctting ispossible, howevcr, due to lhc thcrnloplastic natrtrc of lhc polynrcr;lhe lcndency lo shrink can bc rcduccd by hol<Jing oricnt tcdfi l irments nt l7-26'C. bclow lhc nlclt ing point for I short t imc.-I

his rclicvcs inlcntal slrcsscs.In gcncra l , o r icn t r r tc ( l f i l anrcn ts a rc d i rncr rs ion ; r l l y uns l lb lc , an t l

t cnd to [c t rac l in l cng lh whcn hcutc t l . ' l ' hc cx tcn t o f lhc shr inkagcdcpcnds upon lhe typc ol polynrcr and thc hcat-lrcirlnlcnt it h srcceivcd a[tcr oricnlntion,

A low-dcns i ty po lyc lhy lcnc rv i l l conrnron ly s l r r . ink , on hca t ing .l ruc l t Inorc lhan a h igh-dcns i ty n rono l i l l n rcu t (scc tab lc , p lgc 551 ' ) .

lt ' luntnobil ity

l )o lyc lhy lcnc burns s lowly in r i r , bu t l inc I i la r r rc r r ts l cnd to n )c l larrrl drop away bcforc propugating r f l lrnrc. Vitriorrs inorganic

553

! t t t t l , , ' i E l :I I A N D B O O K O F T E X T I L E F I B R E S

conrpounds tnd pignents are uscd to improvc l lanrc resislancc.Flarnrnabil ity (ASTM Test Mcrhod D635-44);

S low, 1 .0 in . /m iu .

Spccific IIeat- 0.47*0.50 Cal./ 'C./grarn.

Dffcct of Sunlight

The polyelhylcne nolccule is attacked by oxygen, the rcactionbeing stimulated by ultra-violet l ight. Low-dcnsity polyethyleneis nrore susceptible to oxidation than high-density polymer.

The eflect of l ight is particularly serious when the polymer isin the form of f inc fi larnents, which have a high surface-volumeratio. In the carly days of polyethylene nbre, l ight-sensitivity wasa scr ious drawback , bu t the incorpora t ion o f s tab i l i zers hase l fcc ted grer t in rp rover rc r r t s .

Clrernical Propcrtics

Acids

Polycthylcnc l ibrcs havc a high rcsistancc to lcids lt all conccn-trations, and up to contparatively high tcrnpelaturcs, 1-hey arcattacked by nitric acid (oxidation - see below).Resistuuce to Icids (ASTM Test Mcthod D5ll-56)

!\ 'erl,. acids: No eflec tStrong

-acids: Oxidizing acids attack slowly.

Alkalis

Polyethylene libres are highly rcsistant to alkirl is at all conccn-trations and up to comparatively high tenrpcraturcs.Rcsistatrcc to Alkaiis (ASTM Test Method D54l-56)

Weak alkalis : No eflectStrong alkalis: No effect.

(i etteral

Polyclhyleuc, being a parall iu hydrocarbon, is inltercntly iuerl.Polycthylcne fibrcs rrc higl)ly rcsistant (o a witlc rlngc o[ chcnri-cals at ordinary tcnlperaturcs.' lhey arc susccptible to attack byoxidizing agents.

Ellcct of OrS ric Solvcnls

Polyethylene libres are insoluble in most com0ton organic solvcnts

554 )) )

I ] : S Y N ' T I I E T I C F I B R E S

lt rootn - lcnrpcrir t u rc. ' fhcy

swcll and n'l l ly ult inlntcly dissolvc insonrc ch_lorinaled hydrocarbons rnd aronratic solvcri ls, c.g. bcrr-zcnc, lolucnc and xylcnc. Solulions arc obtainccl at 70-gi.C.

Nlineral antl vcgclable oils arc absorbcd and tcud to swcll t l lcl ibrcs, especially at high tcntpcralurcs.

In gencral, rcsislance to solvenls incrcascs witlr incrcascdcrys ta l l in i t y ; h igh-dens i ty ( l inear ) monof i lanrc r r ts a rc rnorc rcs is l_ant t lr l ln low-dcnsity (branchcd) ntonoli lall lcnts.

Insects

Po lyc thy lcnc f ib rcs a re no t d igcs tcd by inscc ts anc l o t l rc r l i v i r r tcrcatures. Thcy nray bc bittcrr throrrgh irr ln lttctrrpt to rclrciiolhcr matcrials tltat are uscd as food.

Micro-organisnrs

Polycthylenc fiblcs lre contplclcly rcsistant lo birclcri ir, uri lt lcwrnd othcr nriclo-orgtrrrisrns,

Ii lcc{ricxl I 'ropcrtics

Po lyc thy lcnc madc rap id hcadway rs t r p l s t i c , l l rgc ly l l l ro l rg l ri ls excellent elcctrical propcrtics. It is ari outsiandi-ng'cl"ct,. ici i iinsulator, especi l ly to higlr-freq uctrcy currcnls.

The electtical charactcristics of lhc polynrer. arc irs follorvs:

Diclc.crric Sr.,,r.g//r (Volts/Nli l. Short t inrc, { inch thickncss)(ASTM Tesr IUcrhod Dl49-59): 500-5t5.

Dielccrric Consrcar (AS1'M Test Mcthod I)l-50-54't '):I kc . 2 .30-2 .41I n rc . 2 .30-2 .41

V olur.tte .Resisrivi ry (ohnrs/cnr.) (AS'l 'M -l 'cst l\tctlrorl D257_5g) :

4 x 1 0 r 5 .

Disipttt ion (pot'rt\ l :(ctor (nsl Nl lcst I\4ctho(lr ) r50-,54' l ' ) :I kc.

100 kc.0.000230.00012

Olhcr I ' roDerl ics

Po l yc thy lenc i s o< lo t r r l c ss and non - l ox t c .

I I A N D N O O K O F T E X T I L E F I B R E S

I'lonlucss ol PolyncrRockwell R (ASTM 'l-cst

Method D7ti5-51): 40.45shofe D (4.5 rl"-l

-icsr Merhod D6'76-449 D: 65-70

Abrasiott Re stance ol Polynter (CSl7 Wheel, nrg.cycles). (ASTlvl Test h4cthod D 1044-55): 5.6-6.1

Ioss/ 1,000

POLYETFIYLENE FIBI{ES IN USE

Thc mauufacturc of polyethylenes, o[ both thc low- and high-dcnsity typcs, is now an important branch of ihe world's plasticsindustry. Polyethylene is a cheap and rcadily-available fibre-form-ing material. But, as yet, only a relatively small proportion oI theworld outpui of lhe polymer is uscd in fibre manufacture. Andthc prospcct of polyethylcne fibrcs being used on a large scaleas gcncra l t cx t i l c f ib res sccms rcn lo tc .

Produclion of polyetlrylcnc fibres is rcstricted almos! entirelyto the cxtrusion of monofilaments or heavy-dcnier multi l i lanlcntyarns , e .g . 1 ,100-3 ,300 d tex (1 ,000-3 ,000 den) .

, Sonre lorv-denier rnultif i lanrenl yarns are spun fronr high-density polycthylene, but these are of minor comrnercial import-ance.

'I 'he development of polypropylene fibrcs, wilh important

advantages including higher sofl.ening point, supcrior stfeogth,rcsil ience and processabil ity, has lelt l i tt lc incentive for intensivestudy of polycthylene fine-denier yarns.

The conrmercial devclopnrent of polyethylene fibres jn lhegcncral texti lc f ield has, fronr thc very beginning, been hamperedby lorv softening point, high shrinkage. lorv stiffness, poor creepcharactcristics, and an inabil ity to takc dyes. These and othershortconlings i lave prevcntcd widespread acceptance of poly-cthylene fibres sincc they first becamc available, and they arcsti l l rcstricting i ls usc to spccialized non-apparel applications.

Lov- D etrsity Polyet hylene

The poor tensilc propcrtics and low melting point of low-densitypolyethylene librcs are deliciencics inherent in the polymer, andlitt le inlprovcmcnt in these respccts can be expccted from develop-ments in processing. The poor resistance to rrltra-violct l ightshown by early fibres is no longer a significant problem; protec-tion is given by incorporating spccial pignlents and stabil izers inthe po lymer .

556

ri- 1-1J-.L-L--L-I '--L '--L - L" [ ' I . L ' [ ' L ' L I L ' L ' U I I

I } : S Y N T I I E T I C F t N N E S

l:tli,""t^j,f"ll| bv incorporaling spccial pigrncnls nnrl st.bilizc.s

,".til;i:TllJ,1lf il,l'",1"u",,,n1;.;i,:,il,J,,,ril,,:,:'ffi l":lllTi [::'i[;i,,;"H:;'i 1'J',, i,'i,fi ;l:;'1": Il, ""'i"i ro*-i"'e"i" "iil;

il;porycrrryie'c i"u.r"r-"r'i"i",ir#;'Jil'l;ii,: bvrxsins low-dcnsitv

I -ow-dcns i ty po lyc thy lcne f ibap'ticrrrions, l,'i*ii,iJ'i"p..' iiit "*.,,,tit"lu,,l',1,'iJl"LJl*t|,|llili",';:';:J1,".',',':',','"fi,,;:::,;"rl,:,:1il;'li[t! v."i.-ii'"v "."","")M gh-D cnsi t y polyct lty le ne

l[,,:'li:r."T*:l S H',"tlil porycthyrcnc rms ovcrconrc sonrc

crysrarinity or rrigrr-trcnsiry,,d:1,$ill:':l,jl$:i;"', 1::""f:;::ill;:[:1;;i,[l'l;.':1;liil].'ii,,'" rotr r t in :cs r r' " r ur io*-l'' ul i "1;olycrhyrcnc), ana a hrgh"r sortl:,,lru;ji:ii:'

that or low-dcnsirv

:[,!J?' j,l ;h1,,,';T^l]:,";fu"1il,,'$,1;il*.,i': ;[;Jllilil:'J.l]; ",';

,,,,3::il'"uJli:i"1,:'i:iff :,,,"?::, ll fibrc propcfl ics, r rrcrc n rc sr i | |

;iiri " ff "n i;:::.'*'i*# T.l,:iiiil itilfil Iapparcl fabrics; dycing rcrrrrins " oro'bt",ir. .;4if,.,;"; ;. ',:^:-:,,:;crclscs persist in fabrics "ft", r;rl;:s1l""t'

rcsilicncc is poor, anrl

. Thc_ applicrtiorrs founcl for trigh_itcnsity polycthylcnc fibrcs

l; il:::+H:i Jl';�,i;:, Ti'i,,:$::i$1 t v "'i'',r'""'l tv rj"i,", n'i"'iii" n-"i.r''*i'"'"'il,;'',j,;;,:;ii*1"1.'j':Tili,if':'i;ii:ll"Jlllf:::r-o ,ycrnyrenc t tb res have thc lowcs t dcr rs i ty o I a l l conrn tc rc in l

[i,;[1.,,:,]l *l]ll"Tl',li::i1i"'1";,l'Jl^ Uj: ixln:i,l*:;iiiiliii: lfi :[.J'';"xni,l;" J,"l:li*ilx;jllil*t x;:E"-"-n

1, .- 100'C., polyclhylcnc fibrcs havc nor bccor;; l;itr-h.

,,, iil;il:xii'J:'" ""]il::,"J"J;,'lruffi ,ixt ;: ;:,,11"!tlx*1,:55'1

IFJJJJ-NFr

r r L - r ' - ' r

l 1

I , I A N D B O O K O I ' T E X T I L E F I B R E S

conditions, where the retcntion of strenglh and flexibil i ty at Iowtenlperaturcs are invaluablc charactcristics.

'fhe strcngth, I ightncss, water- and rol-rcsistance of poly-

ethylene fibres have enabled tlrem to becone established in themarine cordage field. Thcre are great advantages in ropes and netsihat f loat, do not rot and do not absorb water.

FurDilure fabrics, car upholstery fabrics, curtains, protecliveclothiDg, tarpaulins and fi l ter labrics are otl.rer applications inrvhich the special properties of polyethylene fibres enable tlremto compete ellectively with other l ibres, despite their inhcrentshortcomings which restrict their use in general texti le f ields.

Irrallat ion

When polyethylenc is irradiated rvith gamma rays or rvith high-speed electrons, cross-links are formed bctween the polymermolecules.

-lhc movenrcnl of the molecules relative to one anolher

is rcstricted, and the polymer beconres morc resistant to softeningwbcn healed. If cross-liuking is sumciently extcnsive, the poly-c lhy lcue w i l l no longcr n rc l t .

End-Uses

Twines and Nets

High density polyethylcnc nonotilanrent yarns are widcly usedfor the Inanufacture of twines and nelting for the fishing industry.The main features of polyethylene twines and ncts are as follows:

Rot-resistqnce. Thc inhcrerit resistance of poiyethylene tonricro-organisms and to chemical attack make rot-proonng treat-ments rnnecessary.

Tlre strcngth and olher nrechanical properties of polyethylcnenets an(l twin€s are un:rlTected by immcrsion i[ the sea or bybtrrial in the ground for long periods. Ncts and twines madefrom natural l ibres wil l rot under comparable condil ions.

A trawl made from high-density polycthylcne yarn ('CourlcncX3') rvas lost at sea, and recoverecl alnrost a year later. The twi[esshowccl no (letcrior t iol. l, rnd thc trawl wns put into intnrccliatcscrv icc aga in .

558 559

A : S Y N T I I E ] - I C F I A R E S

I!a:d lltcar. 1-lre high initirl strcngth, couplcd wirh crccllcnlwct a brasion . rcsistr ncc, is nrairtaincO tt.,iouet,orii 'tti"' i i l ' i,f"';ia net. Experience has shown tlpory.tr,yr"n. i"qui,l,l ,i,iir,,ii,,iilr1ll[.illl;:" u"'', r,igl,-dc,rsirv

O!t". ul I lanll i .ng; polycthylenc r)cts rc Iightcr th n thoscInadc t ron l na tura l f ib rcs . Th is r r rakcs thc nc t c r rs t r fo l r r rU lc , , , r i J

:: "i:..:f]r""

il,.!:9.ling and hauting in. Thcrc is l"r. ar"e,,"r"rii,ieIn rower tuel costs. polyethylcnc docs nol absorb wlitcr. lrncl isoaked net will comnronty weigh only "rr",ii-ri*-,riiri".l

'il,".iias a wet manila net.

,Cleenlincss, Polyethylenc fi lanrcnts arc snrooth-srrrfrccd, anddo not cling to sand particlcs, marinc grolvth irnd othcr un*i , ir"Jmaterials. This sirnplif ies thc work o[ t lrc crcw_

Rc-tistttrrce tct E:tlcrnc Colu/. trolycthytcnc rctir ins its f lcxibil i lvi lt vcry low lctlpcrlt lrrcs, anrl docs

-not bccorrrc r"iCiJ ;;,;";frcezing concli l ions. 'fhc

wct knot strcngrlr oI twincs incrcascsas Ihc^tcnpcrnturc <lccrcascs. T]rcsc f 'ctirrs -f

" '""i:v l,,, ir". i,, i iwhcn fishirrg. takes ptacc in Arctic watcrs, whcrc thc l, ir t"nrp"ri i-tu re may fa l l to _ 10"C. o r lowcr .

., B.rtoyoncy. The spccific gravity oI polycthylcnc is lcss thlrrrn l l o r wa lc r , tnd ne ts f loa t na tura l l y . Th is rc t l t rces lhc ch l r rcc o fa, nel fouliug,thc propcllcrs, and cut! t lorvrr rl," ,,,;,r,b". ; i ;;,, i ;rDilr arc rc(lulrcd on Dcls. TItc ntouths of t l lc tritwls rcnlir in witlcopen.

Stabil iry, PolycthylcDc nels do not shriDk on irrrnrcrsiott inwalcr. 1-hey rctain thcir shrpc and nrcsh sizc, ,ui,, i,, l i i iut rf, ioangcr o t an ln t r inge tncnt o [ rcgu la t io s ..

S ing lc kuots on ly a rc ncccss l ry in t t rc n r i lDUfac turc o f nc ls r rdr rawrs , so tong as l c kno ls i r rc f i r s t pu l l cd l ig l l t . . l - l l c rc i s r ro r rcc t lfor hcat-trc tnrcnt to stabil ize thc Ktrors.

Ropes

Ropcs rnade. f ro rn h igh-dcns i ty po lyc thy lcnc r ) ro o l i lan lc l t v i ln ts:rre now betng used for a wirlc rangc of rpplications. irornpa in te rs on d ing l l i cs to l roor inB ropcs fo r ta r rkc rs .

I I N D D O O K O F T E X T I L E F I D R E S

E,rpcricucc with mooring and gig ropcs on Lugs has proved thatpolyelhylcnc is eminently suitable for this Lype of heavy work.Three-strand nrooring ropes of 16.5 cnr (6% in) diameter are sti l li n excc l len t cond i t ion a f te r two years o f con t inuous use.

l leavy ropes of 20 and 23 cnr (8 and 9 in) circuruference arcused in a variety ol constructions, including 4 x 2 plaited. Finerropes of 6.3-9 cn (211. - 3 % in) circumferencc are now acccptedin thc fishing i lclustry as quartcr ropcs, rvhilc codJines, l i fe-l incs,nrooring ropes, etc., arc also uscd in increasirrg quantit ics.

Main C lnracteristics

J'l le nrost i| lrportant leaturcs of polyethylenc ropes are as follows:

Lightness. Polyetlrylcnc ropcs arc only two-thirds the wcightof manila or sisal ropes of equal circumfercnce. A polyethylencrope is only about balf the rveight of a nranila Grade I specialquality rope of equal strcngth, and 4l per cent thc weight of acorrrparable sisal rope.

When the ropes are wel, the dil lerence in weight is even moreslriking, as polycthylene does not absorb water-

Strength. Polyethylene ropes are about 33 per cent strongerthan manila ropes (Grade I spccial quality) and 50 per centstronger than sisal ropes o[ equal circunrferencc. Polyclhylencropes of the sanre strength ars manila or sisal ropes are thus ofl3 and I9 pcr cenl. less circumlcrence rcspectively.

Ro!-rcsistencc. Sea-watcr, acids, alkalis and other materialscomnronly encountcrcd in usc havc no deletcrious elfects onpolyethylcne ropes. They nccd ncver be dried out, and are rcadyfor usc tl a nlontent's noticc.

Resil icncy. Polyethylene ropes are very resil ient and casy tousc.'Ihey do not hardcn whcn wet, nor do thcy freczc or hardeneven in lhc most scverc wcatbcr conditions.

Abrasiotr Rcsislance. Abrasion resistance of polycthylene ropcsis goocl, an<l thcy arc very durablc. The surfacc of the ropc maybcconrc flufly aftcr prolongcd wcar and tcar, but therc is noapprcciable loss of tcnsilc strenglh by the ropc itself.

560

- t

561

I

l r : S Y N T I I E T I C F I I ] I ( E S

Buoyatrcl,. Likc ncts and t.wincs, polycthylcnc ropcs wil l noaton water, rcducitlg thc risk of fouling propcllcrs.

...Colouration. Ropcs arc conrmolly lraclc fronr nrass-colourcdlibrc, Thc colours arc vct.y fast to l ight arrd wlrshing.

Filtratiort Fabric.s

Onc of thc -carlicst a;.rplications for polycthylcnc yarns was intlre production of iudustrial f i l tratior jabrlcs. .t. i ,.

.ono" oiproperties olTcrcd by polycthylcnc is prrticularly suitnbli fortt l |s apptrcatiorr, and tlrc f ibrc is being trscd incrc singly for l lr ispurposc.

Jtf dn Characteristics'fhc

main _featurcs oI polycthylcnc firbrics rvith rcspcct to indus-trial f i l lration fabrics arc as follows:

Strength. -Polyethylenc yarns rctain thcir trigh strcngth inprcscncc of walcr, and fabrics arc not rvcukcncd <-hrringfillralion of watcr solutiolls.

Chcnrictrl Resisto,tcc- fhc cxccllcut rcsistancc of polvctlrvlcnclo a w idc rangc o f chcnr ica ls and so lvcn ts i s o f obv ious va lu"in a fabric uscd for f i l tration o{ induslrir l l iquids.

lbra o Resislatrcc. Filtration fabrics rnay bc subjcctctl toconsiderable abrasiorr during rrsc, ancl lhc high ibrasion i"rir i"n""oI polyethylcnc cnxblcs lhc fabrics to withitancl ,u"f, rr."i,r i", i i

Cake Rclcase. ln thc fi l tr i l t ion of scwagc Ii<luids, solid particlcsbuild up into cakcs bctwccn thc laycrs oi nltcrs. . ihcsc

";k", ,;;;rcrnovcd pcrhaps scvcrll t intcs a day by openirrg thc fi l tcr prcsscs,ar)d it is irnportant that thc solid rrrirciinl sl]ould "o,n" o*"uclcnnly lnd ctsily fronr ttrc f i l lcr fabric. I 'otyctlrylcnc is prr'_ticularly good iu this rcspcct.

. l lo.t-resistat.tce . Thc cornplctc rcsisl: lncc of pol),ctl lylcnc toattack by nr icro-orga rrisms is of grcilt u"lu" i,r 'n.,"ny i ittrotionapplicalions, srrch as thc ti l lrntion of scwagc. Cotton-anrt otircrsusccptiblc fibrcs arc attackcd rapidly un<lci such contlit ioni.

t h ct l t c

III

IIl r l

\

;

I I A N D B O O K O F T E X T I L E F I I ] R E S

Dintensionel Slcri itt. Filtration fabrics ntust be able to with-stand Prcssurc used in forcing thc l iquid through lbc press.Polyethylene [abrics are heat-sc[ to provide excellcnt dimeniionalstabil ity.

Corl. In scwage nltlation, which is onc of the most. itnDortantiudustrial f i l trations processes, cotton fabrics have long bcenrused in thc fi l ter presses. Polyethylene fabrics are init ially moreexpcnsivc than cotton, but their extra useful l i fe outweiehs thiscxtra cost. lxpcrimcnts carried out by Spenborouglt Corporation,England, shorved that in sewage li l tratjon, cotton;loths cost O.glpencc per pressing, comparcd with 0.492 pence per pressing fora polyethylene ('Courlene X3') fabric. Cotton disintegrated after76 pressings, rvhereas the polyctbylene fabric was satisfactorv uDto more than 350 prcssings.

Other synthctic f ibre fabrics wcre used in this year-longpractical experiment, but they had thc disadvantug" of blinain!afler some 200 pressingsj their costs were iD the rigion of 0.62ipence per pressing.

Il l inding rcfcrs to the blocking oI thc l i l tralion [abric to thepoint.at which rvrshing does not lree the fabric of f i l tereclparucles,

Blintl.r, Ay;nings and otl:cr Ouldoor Fobrics

Polyethylene offers an attractive range of properties to theinanufacturer of blinds, arvnings, deck-chair and olher fabricsfor use ouldoors.

Main C harccteristicsThc nrain characteristics of interest in this respcct are as follows:

Colour ond Transparency. Piglr)ented polyethylene is avail-able in a rvide range of attractive colours. The yarns are contmonlytrauslucent, but opaque matcrials may be obtaincd by usingdarkcr coloured warp and wcft yarns. Tests show that 95 pcr ccnio I thc r r l t la -v io lc t rad ia t io r r in sun l igh t i s d ispersed on lhcsurfacc of thc polyelhylene fabric.

Rot-rcsistatrce. Itolyethl,lene fabrics arc completely resistant torrricro-organisnrs and insecls, and are ideal in lhis respect for uscoutdoors. Polyethylene fabrics need not be dried belore storagc.

562

U : S Y N T I I E ' r I C r I S I I E S

. Ligltt-t.ctistancc. Polyctlrylcnc l lrbrics arc slabil izc<l to rcsistd -cgr i r ( l i r t io l s t in lu la tc ( l by l igh l , an t l havc a long ou t ( loor l i f c .'fhe

pignents lockcd in the fi lanrcnts bcforc spinri irrg arc flst tolight and water, arrd colours rcmain bright.

Chettrictt l I lcsist4ttce. Ouldoor frbrics arc subjcctc<l to tI i lckby t l )c po l lu tcd u i r o f towns an t l c i t i cs , wh ic l l con t i r ins i l v i l r i c tvo f ac ic ls and o thcr cor ros ivc c l rcnr ic l l s . po lyc thy , lc lc i s una l l cc lc t lby thesc pollutanls, rvhich bring about lhc rapid dccay of rrrorcsensitive fabrics.

Watcr Re;istance. Polyethylcnc retaius i ls strcllgtlt an(l lcitrresistancc when wct. lt clocs not absorb nroislurc, incl is quick-clrying. Fabrics are stain rcsisling, and arc c:rsily clctrncd rvithdetergenI and waler. Polycthylcnc fabrics ntty bc coalctl to nurkcthem watcrproof if dcsircd.

A hro.\io

I lcsistutrc.c. Otrldoor falt l ics ntrrst rvilhst rrcl rorrghhandling, antl arc oftcD subjcctccl to gt.cirl rvci[. arrd tc:rr. I. i icabra-s ion res is tancc o f po lyc thy lc r rc i s cxcc l l c r r t a r rc l ou tc luorI i lb f l cs a re lough and hard-wcar iug ,

Lotv-tentieraturc Rcsi a;cc, Undcr thc scvcrcst winlcr condi-tions, polyethylene rcrn ins strong and Ilcxiblc.

Dcusity.'fhe low dcnsity of polycthylcnc in conrparison rvit lrother l ibres is a greflt ldvanta.gc in dcck-chair and sinri lar fabrics.fhc l ightness of polyethylenc fabrics sinrpli l ics hanrll ing problcrrrsin outdoor furniture which is constantly nrovcd about.

Sig t rit ing. Awnirrgs anr.l thc l ikc lrrc oftcn rc<luirccl lo clrryaclvcrl iscntcnts ancl signs, arrd polycthylcnc firbrics ollcr | lodil l icull ics in tlt is rcspcct. Spccial inks lrc irvailablc for t lr ispurposc.

I!edt-scuing. Dinrcnsioual slabil ity is cxccllcnt in hcat_sclpolycthylcne firbrics, and r varicty oI attrf lcl ivc cntbossc(l c{lcclsnray be obtained by hcat-trcatnlcnts.

563

I IANDDOOK OF ' I 'EX - I ' I LE F IDRES

(2) POLYPROPYLENE F]BRES

Fibres spun from polymers or copolymcrs of propylcne:

CH!:CHCH,

Polyptopylqre: S!ctic,ltructdLtR iqh t : Thc rn r i n cha in o f ca rbon a toms fo rm in l t i : r . b ] ckbo c ' o f i rmolcculc .of vinyl ic. (Cl. l ,=CHR) polymcr maybc considcrcd as azr8-zag ryrng on a ptanc.

ll) Isotacric l,ollt,rcr (top). 'I'hc R groups are all on one side of thc

plane.(2\ ,Sr ' , tdiotactic l ,ol lrrrcr (nridrJlc). Tlrc I{ groups l ic ir l tcrnatcly abovc

i lno uclow l l le nlanc.(r)",J,f:i;"_t[ilJ,l",i,{bottonr). The R sroups appcar in any or<lcr above

, .Lc t t : S t r css -s t r l i n cu rves o [ ( l ) i so tnc t i c po l yp ropy l cnc , ( l l ) s t c reo -DlocK Dolypropylr c, n ( l ( l l l ) nl :rct ic polyf 'rop),1(nc.

I trc (t t t lcrc[ces bclwccn lhc c rvcs arc not duc lo t l tc dif lcrc,t tnrolecular_ rveighls of thc thrcc types of polypt nDylelrc but to t i i lTei-crrccs fn lhcrr slcrrc slructUrc - Ciba RCvicw.

564

\

7

. . . 0 '

,-1- l- L- L-L=]=*L. - - L _ - " L - L ' I . ' L l L l ' L _ i

-l'hc. succcsslul polynrcrization of cthylcnc, using organomclall ic

ill"lLi,i;111, i!'i1i:i "?'';li:lHl.,ll' il:,ff:ii{*,*liilll[! f "f : l!i,i]:x! x?l llil:i._::: " Jr,:"lt I ::,1":i' jilhllt)rolcssor cit|tio Natra ot Mihn notyr""l,i, i",' rinif,

'oi*"".;'j

lilil:T;ffi ';{:'tJff:,'l'l'fi ;il,,l,,,"111';l'i,,;,':ii;[";l',,l;

:i!!i'r.,:: ;i,1[':,;:'*i::: il',ff','::ilJ];l',:';iy,:,,ili"lli:i:i :::r n;:..* ""*:l'n, il'i,: fi l :l,r;liln,l;ru:,tarrd sonle crystall izcd whcrc otlt;ii;;;;: ;J; i;fi ; ;:; ;, ;'"##;ililT"liffi i1"",1,";,":1il;. X-ray and infra-rcJ invcsligat

:t i,,:", hi.",? %ii';il:*fTi;lr ir"r ',l; j* i::nll ","millrangcn)cnt of lhc ntolcculcs in

;;;:;1'11l,l"h[,,[rl "lffi;::i1l;l'l':1;::

o,,r..ry r",riion,'n; iii::"";,';i;.11i","',*;l:lJ'i,,y*"::::1,1,",:iJ:melting, low-Jcnsily polypropylcnc.

S tereorcguktrity-l

lrc nrolcculc of polypropylcnc consists oI a long chain of carborr

;l;ll'i # iil1":i'l #""1,',,:"leiril,l'i#:,:'rf,.:',,",txlfl,l,,.., i f:ii,1",;'lil':;'i;,i"lllfi;:,l:Jil:' in a varictv "r r"i"i' *i'li, )irri,

ll.d;i:,ii ;li;':l' ;lilil,,l'-lli-i',';"Jll.,li,l,J:"1:?"r, ;j

s Y N t E l t C F I t r t [ s

rN f tToDUCTTON

ll.I9:-:. lf rtrc notynrcr n,ot".ut. .oniist* "; "';ti:;;;t;tl::l :::o::.:,:,'ll.:hict,nr;ry 1," co,,,'ta","J. i,-iri;;;;'iffi ;il;i:ll..'11:._lir-"I: .Evcry .si<lc-gr.oupi"e trrf ,i",y'ir,i,,'it'r,,'",i1"'ji,'";;,1?:lliu''l,ll.,',:ry uc rrtirvc ir,"l,r"n" i,r ii"i'";";, ;';j.iiu i:

ii::,i::,::jll::.1:cosnizccr,r ha r ccrriir,i il,.L' i Jp.i ;i ;il 1,:srructrrrc wcrc nradc possibtc by rtrcsc altcrriaiiv;,;;,;;,i;; ' i i;:

565

. I T I F I l F F F F .I I A N D A O O K O F T E X T I L E F I O R D S

( I ) ISOTACTIC POLYPROPYLENE

CH" CH" CH. CH,-cHz cH cHz cH cH2 cH CH2 CH CHz

cH .l -

c H c H ? -

(2 ) SYNDIOTACTIC POLYPROPYLENE

CH. CH. !".-cH, cH cH, cH cH? cl l cHz cH cHz cH cH2-

CHT CHT

(3 ) ATACTIC POLYPROPYLENE

c H l c H ,l - t _-cH: cH cH, cH cH2 cH cHz cH cH2 CH CHz-

r t lCHT €H: CHT

Polypropylene

566


O = CAREON ATOM

O 5 METHYL GRoUP

l.rota.t ir .pol),propvlcrrc. ' l

l rc bulky Dtct l tyl Sro ps t!rkc lrn n qlcs of120'r! i th respecr ro ncigtr bourr ng inc rh yl 'grf,upsi t t Lrts- nr" t". ' ,?i* irrr"r in regUtar I)cl lct l or sptr. : l l structurc as sltowrt.

s;dc groups, lnd hc glvc tl lctn narucs by which tltcy rc nowgenerally known.

Atr isotactic structurc is onc in which lhcrc is a rcg l itr rcpcti-t io r o f un i ts o I thc s r r r rc conf ig r r ra t ion . f t , " s idc g r iups ar l ; i lroc i l l cd on l l t c s i ln lc s idc o f lhc backbonc p l l r r rc , ; rs i l l hc r rppcrdiagranr of f igure on page 564,.

A sy diotactic s|Ictrtrc is, onc in which thcrc is a rcgtrlarscc lucncc o I a l tc r r ra t ing un i ts o I opposcd conf igur l t io r rs . " . l l r cs loc

.g roups . a rc Iocn tcd in scqUcncc o f a l tc lna tc s idcs o f thct ) rcK bonc p iane, as in t l rc midd lc d iagram.

At1 otoctic structure is onc in which the unils arc distributcdirrcgularly f l long thc nrolccular chain. Thc sidc groLrps,ir; i ;; i ; ion cithcr sidc o[ thc backbonc chain in rnndonr iashion, as inthe lowcr diagram.

. In thc_ casc of polypropylcnc, Incthyl groups arc attrchcd tolhe Dackbone cha in o I c r l .bon a ton)s , and thc t l ) rcc cor resDond i r ) !s lcnc s l ruc tu res arc shown on pagc566.

(l) Isotactic P<tlypropylcne has all thc nlclhyl groups on thesame side of thc backbonc olane.

(2) Syndiotocric polyptopylcnc iras nrcthyl groups on altcrnatcsides of the planc.

(3) Atactic Polypropylcne hls mcthyl groups clistributcd inrandonr fashion on both sidcs of lhc planc.

. -l 'he

slcric arrangcnrcnt of thc polypropylcnc nrolcculc has animportant. influencc on thc properties of thc polymcr. Isottrctici lnd .syndto tac t ic po lypropy lcncs ( i . c . lhc , tac t i c ' po ly rncrs ) a rcrcgular struclurcs, and lhcir regularity "nutrt"s it.,c

' nlote",i i"s

5b7

?!cir,0 c'r/c,,c'',),

( ) c l tO or,O n

I I . \ N D B O O K O F T E X T I L E T I I J R E S

Ilolical S!ru.cturc. Thc asyntrnctry of thc -CII,-CHR- nlonorncrunit oI t lrc isot;tctic poly-a.olcfin mikcs thc lorruttion of svn,rnctricirlcrystals irnpossible save in tbc case of helical chains-thc onlv cascwlrerc all the mononrer rrnits of a poly-a-olcli

cnn attcin structuralequivalencc. All thc Nain chains of isotactic polymcrs are thcreforehc l i ca l in thc i r c rys ia l l inc s tn rc . Shor t l y a f tc r - i r i d iscoverv in 1954.thc first crystall i e polynter of propylcne was found to be isolacli;and to h lvc_ a hc l i c r l chn in . lndccd, c rys la l l in i t y o f thc v iny l i c po tyn lc rsciln rcsult fro|lt lrvo sir plc strUctrlrcs only, iarncly the'isoticti6 anrllDc synd ro l i r c t t c .

, Thc. f igurc abovc shows thc di[ Icrcnt types of hel ices present in'solact,c polyrners ol knorvn structurc.

-f hrcc-dimcnsionfl l crvshls

r cqu i r c no t on l y a regu la r s tn t c tu r c o f t l t e i n ( l i v i ( l un l c l r a i ns . bu I l l sor r cgu la r pack ing o f t hc cha ins i n n d i r cc t i o l r t r i ch t an r l cs t o t hci lxis of thc cl)r in. I I only t l tc l i rst condit ior) is r ict, air l not rhcsccond, as tn orie l i t ted and qrrcnchcd rnxtcrials. sntcct ic and inconr-plelcly crysl: t l l izcd structurcs of lower density and greatcr transpxrcn.yrcs\tlt - Ciba Revlctv.

to pack logcthcr in an ordcrcd fashion. These polvnrers arecrys t i l l i r c .

Alac(ic polypropylenc, orr thc othcr hand, is an irregularslfucturc, lnd tlrc nrolccrrlcs cannot assun.lc a crystall inc slruclurc.'fhis

typc o[ polynrcr is anrorphous.

568

i lL1n-='" L-' f L Ll Ll L_' L I Ll t l l l l r t

L T L \ I

N : S Y N T I I E T I C F I B R E S

Thc first cryslall ine polymer of propylcnc was cxanincd shorllyaflcr it was madc in 195.1, and found to bc isolactic.

-l 'hc sidc

groups in this polymcr rvcrc arrangcd in lrclical fashion, thcconccpt of the flat plrne o[ thc backbonc bcing only a convcntionwhich cnablcs us to rcprescnt the steric slructurc on prpcr,' l 'hcnglrrc on page 568 shows thc difcrcnt typcs o[ hcliccs prcscnt inisolactic polynrcrs of known structurc.

Stereoblock Polyncrs. ln addition to thc isotirclic, syndiotncticand atactic types of polymer, lhcrc arc intcrmcdialc typcs havingisotactic or syndio(actic sequcnccs so short that crystall izrblc alrdnon-crystall izable parts cocxisl. in the sante long moleculc. Thescare 'slereoblock' polymers. They arc lcss crystall irrc Lhan idcalisotaclic or syndiotactic polymcrs, and thcir nrechanical properticsarc inlermediate bctwcen thosc of the tactic a|ld thc tacticpolymers. Stereoblock polymcrs thrrs havc lowcr lcnsilc strcngthbut grcfltcr claslic clongitt ion than isotrctic polynrcrs (scc figurcon pagc 570).

Stcreospacific Polynk'rizutio l,roccs:tcs'l 'hc polynrcriz;r t ion proccsscs dcvelopcd by Karl Zicglcr, GiulioNat ta and the i r co l leagucs wcrc in rpor lan t no t on ly in p rov id ing

In(: l l - CI Il lca( l - to- ta; l

t lcad-ro-hcad-

tr i l - lo- t i i l

l 'ol \"t tcr izat ion. l lcul onl Toi l Linkages, Polyl lcrs wilh n chcnric:r l lvregular structurc arc fornlcd by tsymmctricir l nto| lo crs (Cll ,=CIl l t)only whcn the nronorlrcr units nre l inkcd in l part icular ordcr, i .c.hcad-to-tai l or lrcad-to-l tcad-tai l- to-tai l scqucncc.

l lcrd-to-tai l scqucncc is frc( luc t, but ' in sonrc polyntcriz.:r t ions i tnray bc accompanied by irrcg[lari t ics duc to rtrrdoti l l lcnd-to-hcnd orlai l- to-tai l l inkagcs. l f thcsc irrcg[l i rr i t ics cxcccrl ccrtr in l i rni(s. thct.nr.ry lcad lo a rcdrrct ion or conrplctc disappcitrancc of crystal l ini l l- C iba l l c l i c l .

[-clrt-.cr r-crrr-cr r,cn,-cr r-crr,-crt-

II R r{ R n J n/*

RI

ncl I . : CII [-ClrrCI{-CI[-cl ]r-Cl lr-cl l-C}l-cIIr- IL Ir R R R I u/ l

569

It I

t

St creoblock Poll' pro p5'lcnes. Strcss-Stoitr Diagranrs. Stereoblock poly-nlcrs have lo\r 'er tensi le strength and grcater elast ic elongation thanisotactic polynrcrs. ( l) refers to a polymer with a hiSher nrolecularlvciglrt than (I l) - Ciba l levicrv.

l irrcar polynrcrs of propylenc aDd othcr alpha-olefins, but inestablishing such control over the polynlerization that polymersof dcsired steric structure could be made. Thc proccss could becontrolled to piovide an isotactic polypropylenc, or r syndiotacticpolypropylcne, or an atactic polypropylene. ' l 'he

tcchnique hasbccome known as stcrcospccific polynrcrization.

This renrarkablc developn'rent in polyner cherristry wasachicvcd by using vcry spccial typcs of catalyst arrd by controll inglhc rcaction conclit ions with great carc. Tlrc production of auisotaclic polymcr, for cxarnplc, rcquircs not only rcgular 'head-

to-tail ' l inl<ing of thc monomeL nrolecules (sec figure on page 569),bul also a constirnt opening of the doublc bond (always crs oralways lrarrs) and conslant positiorriug of the monomer withrcspcct io the plane in $hich thc double bond lics.

570

s Y N r | | t : i t c F l t l R D s'l 'hc

tcchniqLrcs usctl prcviously in polynrcliziug alplra-olclirrscor r ld no t b r ing about u p |cdc tc rnr incd pos i t ion ing o f thcmoDomcr iu rc la t ion to thc g rowing c l r ; r in . l t cgu la r i t y o fpos i t ion ing is ach icvcd on ly by accufa tc o r icn t i l t iou o f thcr]louonrer towards the c talysts i\t thc sti lgc inlnlcdiutcly prcccd-ing i t s add i t ion to thc g rowing cha in .

l ' hc c ta lys ts uscd by Z icg lc r in t l l c lowtc t r rpc t tu rc po ly -nrerizalion of cthylcnc nradc possiblc lhc l irst slcrcosDccil iclcchniqucs. Ethylcne itsclI is ir symnrcll ical l lolcculc, und lltcl incar polyethylcnc rnolcculc docs not displuy stcric dil lcrcnccsof lhc isotactic, syndiotxctic :tnd rtirctic typc. nlso, clhylcnc isa morc rcactivc subs(ancc thutr propylcoc and thc higlrcr olclins,and thc Zieglcr catalysls uscd for polymcrizing cll lylclc do uotncccssarily polymcrize propylcnc at all, nruch lcss polyltrcrizc itlo a stcrcoregular polymer in high yicld.

Delorc thc disrovcry of stcrcospccil ic polynlcriz.i l l iott, thc oolyl inc r r r po lyo lc l ins o f h igh r lo lcuLr lu r wc ig l r t rv l r i ch cor rk l bc n r i rdcrvcrc tlrosc dcrivcd frorrr olclins rvit lr i l synltnctricrl slruslurc(cthylenc, isobutylcne). l lrtt the ncw slcricir l ly-cot) I Iollc(l l)oly-t|rc[izi lt ion proccsscs rrrakc possiblc l l tc Dolylrr clizi lt ion ol olclirrsh igher thu t c thy lcnc , and thc co l )o lynrc r i z i t l i on o f thcsc w i t l lcthylcne. Higlr nrolecular wcight products atc obli l incd which,dcpcnding upon thcir slnrcturc iurd contposition, uuy bc ofcommcrcial valuc.

Conrrtrcrcial l)cvcloprDcnl-fhc

l irst pitcnt f l l)plicirl ions on polypropylcnc wclc fi lcd byPro fcssor G iu l io Nat ta in con junc l ion w i lh Pro lcssor K l r lZiegler in 1954. 1'hcy covcrcd thc nrcthod :rncl conrposition ofnratter, with spccil ic claims for thc productio|l of f inc fi l tnlcnts.

Produbtion bcgan in ltaly by thc firnr of Montccatiui .Socictl( icneralc, f irst in onc irnd thcn in two pl nts. l ly 1957, conrntercialquantit ics of isolactic polypropylcuc bccanrc avail irblc fronrMontecatini in lt l ly. N4canwhile plans for largc-scalc productionof thc polyrrcr htd bccn nradc in thc U.S., U.l(. i\ud othcrcoutrtries, and by I962 scvcral nrtnufi lclurcrs in thc U.S., anrtI.C.l. Ltd and Shcll Chcnrical Co. in thc U.l(. had bcgrrn pro-r luc ing pc lypropy lcnc .

lvluch of thc init ir l irnpctus bchind lhis dcvclopnrcrrt of poly-propylcne canre from thc potential it olTcred as a plastics nrl lcri l l .Polypropylene is similar in nlany rcsl)ccls lo polycthylcnc, l)ul

571

I

I I A N I J I ] O O K O F T E X T I L E F I I } I I E S

thc incrcased tcmpcraturc-resistancc, greater s(i[Incss and slrcngth,bcttcr surfacc l inish and otl]er propcrtics give it advantages overpolyethylene in nlany applications. Like polyethylene, it is madeironr a r"w material rvhich is available in almost unlimited quan-

tity at a low cost.t)lans for the production of polypropylene were pushed ahcad

with grc t entlrusiasm, tbe U.S. production capacity for 1964

be inq se t a t n rore t l la t l 250 mi l l ion kg a yer r , r i s ing to about

450 ln i l l i on kg a year by 1961 . ln o t l te r count r ies . no tab ly l ta ly ,

the U.K. and Japan, polypropylcne production went ahead witheqrral vigour, ths planned total capacity of countries outside theU.S.A. be ing grea tc r than 450 mi l l ion kg a year by 1967.

Tl're aclual ploductiorl of polypropylene, horvever, wa-s veryn luc l r s lowcr lhan an t rc tpa ted , and the deve lopmcnt o l po iy -propylene nbres did not procced as rapidly as the more optimisticforecasts had pledicted. lt was not unti l the early 1960s thatsmall quantit ies oI ltalian-made staple fibre and multif i lamcrtyarns began to appear on the market. Soon, this was followedby supplies of ftbre from U.S., Brit islr, Japanese and other pro-ducers, but evcn by 1963 thc U.S. consumption of nne texti lesracle olelin 0bres rvas sti l l belorv 5:uti l l ion kg per annunr.-'fhe

reasons for this comparatively slow development of poly-propyleue fibrc rvere partly economic and partly technical.

Ecottotnic Faclors

ln thc early stagcs of polypropylctrc dcvclopment, too nrtlcl)crnirhasis was placed upon thc prospcctive low cost of the isotacticpolynrer itself.

' fhe raw nraterial, propylene, is available in

quantity at a low cost, and many prophets assumed that thepolypropylene polynrer and fibre would necessarily have aninrprcssive and imnrcdiate cost advantagc ovcl competit ivcproducts.

Early forecasls oI polypropylene as cheap as, or cheapcr than,Dolyelbylcrc provcd to bc trtrrcalistic. Thcy did not takc intoicc 'o r r r r I t l r c v i : ry hcavy ( l cvc lopr t tc r l t cos ts , rv l r i ch l c l t l c t l co t ts i t l c r -ably lo the cost per kg of polypropylerlc produccd.

ln lhc U.)-., whcrc tltc (lcvcloplncnI of polypropylcne waspushcd ahcad with great cnthusiasm, thc cost of polymcr was

nra in ta ined in i t ia l l y a t a round 20 cc l l t s Per k8 . l }e tween l96 l an t l

5'12

lF r l t r 1r I r I f r r ' . l t - r i r r i r - ' r , . - -

|

r \ r I r l , I

I : L-- L_ J U L L|-L-_L'-L"+ LO t i L L L U I L] U

r ] : s ] ' N l G r I C I ; t I t t E S

1961, i t f c l l sor ] l cw l r i r t , bu t s l i l l r cnr r i r rcd too h igh fo r ( ib rc tobc produccd at x rcirl ly conrpctit ivc pricc. lry 1964, thc pricc ofpolycthylcne droppcd, bringing polypropylcnc dorvn too, rcachinga leve l o f I I to l4 cents per kg , dcpcnd ing or t g r rdc . ' l l t c p r icc o l -polypropylene staple fibrc in latc 1964 rwrs 29 ccrtts qrcr kg.

I\, lc:rniin1e, thc priccs o[ cstrblishcd synthctic f ibrcs wcrc alsonrovinl down, partly to nlcct lhc thrcrt ofltrcd by polypropylcncin ccrtrin nrarkets. ln lr lc 1964, nylon staplc was scll ing in thcU.S. at $0.45 to $0.40 per kg, polycster f ibrc at $0.44 attt lac ry l i cs a t $0 .49 to $0 .36 pcr kg , depcnd ing on Bmde rnd dcn ic r .I ly this time therefore polypropylcnc hatl achicvcd a substtntialcos t advantage, wh ich was incrcascd s t i l l l u r t l te r by i t s lo rvdens i ty ( i .e - more bu lk per kg) .

7'cchniu Factors

In the developmcnt of polypropylgrc Iibres, n nuntbcr of tcclrIt icalproblcnrs havc hacl to bc faccd.

L IIear Satsitivity

Polyolcfins are inhercntly pronc to dcgradalion by oxidrtion,which bccomcs progrcssivcly morc scrioLrs as thc tcnrpcr lurcrises.

-fhe firsl. conrmcrcial polypropylcncs tcndcd lo rrndcrgo

cousidcrablc molccular brcakdown at thc cxlrusion tcrrpcrirturcs( l l0 -190 'C. h igher th ln lhc mc l t ing po in t ) . As bc t tc r -g r i ldcpolynicrs bccanre availablc, lhc heat-stabil ity improvccl.

This problcm ol hcat stabil ity is inrportant, too, io i ls influcnccon thc bchaviour of the nbrcs thcnrsclvcs. and it has bccn ncccs-sary to dcvisc strbil izing systcnls which wil l prcvcnt or rcducctlte dcgradatiou causcd by clcvulcd tcnrpcraturcs, Indivi<lual poly-propylcne manufacturcrs havc dcvclopcd thcir own systcms forthis purpose, and a rangc of f ibrc-grirdc polymcrs has l>ccorncava i lab lc , cach w i t l r i t s own hcr r t -s tub i l i l y charuc tc r is t i cs .

2. Light Stabil iry

Thc oxidalivc brcakdown of polypropylcnc is accclcralctl byl igh l , and thc unDro tcc tcd [ ib re i s scns i t i vc to u l l f t r -v io lc l n r ( l i : r -t ion. ns i|r lhc casc of hcat-scnsitivity, lhc arrsrvcr hls bccrrto dcvclop stabil izcr systcnrs. Thcsc may includc ultrl-violcl

It

, l

i

l

573

I I A N D A O O K O F ' T E X T I L E F I O I ' E S

absorbers and conlbinations oI scvcral antioxidants actingsyDcrgistically. Non-extractablc syslcms nre prefcrrcd for gcncralusc, and arc essential Iot some applications.

3 Meltirrg Point

The softcning and melting poirrts of polypropylene are low bycomparison with most (but not all) cstablished synthctic f ibrcs.-fhcy

are sufi icicntly high to enablc polypropylenc fibres to bcuscd in gencral texti le applications, including apparel uses, anddo Dot raise any rcrl dil l icult ies iD this rcspcct: PolypropylencIabrics can bc ironed, but a grcatcr dcgree of caulion is rcquircdlhan is nccessary with most othcr established hbrcs. This l inritationhas lendcd to be a promotional disadvantagc which wcighs nrorehcav i l y th t rn i t shou ld .-fhc

comparatively low softening point has provcd a morescrious disadvantage by placing l imitations ou tlte lemperaturcswhiclr may bc uscd in fiuishing opcratiorrs. ln blcnds wilh cot{onor rayon, Ior example, polypropylene nray be subjccted tofinishing procctlurcs which wonld nornrnlly involve heating totcnrperalurcs higher than it can st Dd without softcning. lt isnecessary, therefore, to use finishing tcchniques which do notinvo lve ten lpera tures grea ter than about l25oC.

4. Spinting uul Ptoctssirtg

The cxtrusion of polypropylele, and the processing of the fibre,do not present any basic dif i icult ics. ' I 'he

tcchniques used areesscntially similar to those already developed for melt spinningother synthetic polymers, notably polyanrides and polyesters.

Thc stagds of spinning and processing had to be adapted tosuit thc charactcristics of the ncw polymer, however, and con-trolled to providc for requirements of specil ic cnd uses.

'fhese

lactors raised sorrre problems.Variations io the characteristics of dif lerent polypropylcnes

wcre alrcady causing difi icult ies, as outl incd abovc. But the fibrc-rnanufacturer found also that he was rcqtrircd to produce moregradcs oI polypropylene fibrc than was usual with othcr typcsof synthctic f ibre.

lnit ially, polypropylcne was introduccd as a Irigh-strength l ' ibrervhich compared in tcnacity rvilh nylon. Once lhe lreat-stabil ityand otl ler polymer problems had been solved, there was no

5't 4

a : S Y N T

A I I C F l l l R E S

diff iculty in producing fibres rvith tcntcit ics itt t l lc rcgiort of

53 cN/tex (6 g/den ).It was thcn found, horvcvcr, lhat for ccrtain rpplicl l ions it wls

prcferable to use a u]orc rcsil icnt crinrpccl stlplc l ibrc wilh lrlower tenacity, e.g. in the region of 26.5 cN/tcx ( 3 g/tlcrt). l ior sotrtcapplicatioDs, on thc otlrer hand, such as ro1>cs irnd l ishing nctsa high tcnacil.y continuous fi l irnrcnt polvDroDvlcnc wls rc<luirctlwith tenacity ol 7l -80 cN/tex (8-9 g/dcn).

-fhe abil ity to influcnce tlre physical propcrtics oI polypropylcrrc

by varying thc conditions o[ spinning irnd proccssirrg lrls rrr:rt lcpolypropylene into onc o[ lhc nlost vcrsati lc of all synthctic f iblcs.But it has, at the sarne time, creatcd unusual problcrrrs for thcIibrc-manufacturer who must spin and proccss polypropylcrrcrunder prccisely controllcd conditions.

Control of elongation and shrinkagc, crirrrping irnd crirrrlrretenlion becanre neccssary to providc fibrcs with spccitl chrrrrrc-tcrisl ics, sLrch rs high brrlk pcrfornlrncc, or for blcrrrl irrg rvithothcr l ibrcs. Spccial considcratiou hltl to bc givcn to Ilrc plo-duction of polypropylcne fi larncnts which worrld bc sul)icctc(l totlrc various bull i ing and tcxturing proccsscs rrow in widcsplcrrtlU S C .

5. Dycing

Unmodi l i cd po lypropy lcnc f ib rc i s v i r tua l l y un t lyc rb lc by n rc r rnsof the stand rd products nd tcchniqucs usctl in t lrc tcxli lc lr itdc.This problcm has bccn a major factor in slowing up tlrc acccp-tance of polypropylcnc as a gcncral tcxti lc l iblc.

The use of pignrentetl f ibrc has provccl sntisfnctory for rrrrrryapp l ica t ions . Mod i f i ca t ion o f thc po lynrc r o r o f the f ib rc s t ruc tu rcto pronrote dyeabil ity has not provcn to bc ;r pronrisirrg l irrc ofruack on this problern. ' l 'hcre

are now sevcrrl ntodifictl polypro-pylene fibres on the nrarkct which arc rlycablc but thcy rcprcscrta very s r r ra l l par t o l - to ta l p roduc t ion .

lrn(urc ltrolrrcc(s

Wltcn thc dyeing and olhcr problcnls havc bccn solvcd, poly-propylcnc fibrcs wil l bc aviri lablc for unrcslriclcd usc in l) l irrkct\,knit goods, upholstcry frbrics, swcirtcrs lutl othcr apparcl fubrics.It wil l bc in widcsprcad usc in thc wontctt 's lrosicry nrrrkcl.


ll. is safc to predict that the next decade or two will scc alrcnrcndous dcnrand for an incxpensivc, serviccablc, availabletextilc nbre that will be necded in very large quantities. Atthe presenl time, polypropylene is the only fibre developed ortheoretically feasible that can combine serviceability witli econ-onry and availability. It seems certain, therefore, that polypropy_Iene fibres nrust bccomc tbe'cotton' of synthetic librcs beforc iheetrd of the twcntieth century has bcen reached.

TYPES OF POI-YPROPYLENE FIBRE

By vary i r rg thc condi l ions of polymel izat ior r , sr r inr r ing and oro_ccssing, it is possiblc for the manrrfacturer to influeucc thc phyiicalproperties o[ polypropylene fibres to a rcnrarkable aegree. fnconscquence, there is a very wide choice o[ polypropylene fibreson thc markct, which difler iu physical characterisiics over acorsidcrable rauge. Each ruanulactuler nrarkets the types oflibre rvhich he believes will satisfy the needs of his oiiticulaicustomcrs.

In addition to this variation in the properties of polypropylenefibrcs 2er se, variations are introduced in a cmpts io nioAifv tt.dycability and othcr characteristics of the fibre. Thus, Iibrci arenorv on the nlarkct in which afl)inity for particular typcs o[ dyehas becn increascd by physical or chemicil nrodificaiion of thcporyt er ,

Polypropylcne fibres are producccl in thc form of rnultifi lantcntyarns, monofilarncnls, staple fibre and tow, Thcrc is a widc ralecol prgrncnte( l l ibres and there is a l inr i ted l rur lber o l c lyerb lepolypropylcne fibres.

lvlnrry manufacturets arc now producing polypropylcnc hbril_lating nlnr or slir-li lrn Iibres.

NOI\IENCLATURE

OlclinPolyprolrylene fibrcs are delincd as olefins under thc U.S. FcdcralTradc Conrnrission definition (sec page xxvi).

576

. U U U U U U U U L J U U U r ' L i J U i l u

A : S Y N T I I E ' T I C F I E I { E S

Polyoleliu

Plopylenc is chcrrrically a nrcnrbcr o[ lhc olcfin class o[ hydro-carbons, and polypropylcne is a polyolcfiu. I 'olypropylcrrc i ibrcsare thus a typc of polyolclin fibrc.

PRODUCTION

Monorner Synlhcsis

l\ 'opylcuc is a constituent of lhc rrrixturcs obtaincd front thcrnlir land c.atalytic cracking proccsses in thc pc(roleutn industry. ltis available .in virtually unlimited quantity and at potcntia y'vciylow cost.

I'olynrcrizalion

Tllc actual conditions undcr which stcrcospccific polynrcrizationof propylene is carr ict l out arc not t l isclosct l i r i . f i r r i f i iv i j , .r f ranufacturers. Zieglcr- type catalysts arc usct l lscc pre. i l i l .sucn as an org l lo . rncta l l ic cor lpourr r l o f a lurr r i r r iunt i i t i l tc r l rc i_er)ce o l t i tan iurn t r ich lor idc, ant l t l re rc : lc t io l is carr icr l or r t u l r r lcrlu at rnosphercs prcssure at lcss tharr 80oC.-l'he

catalyst jn this rcaction controls lhc rvay in which tlrcpolyrner is built up, fccding each nronotncr ntolccrrlc to thc cnclo[ the polynrcr chain in such a way that it adds on in llrc dcsircclposition. Thus, an isolactic potypropylcnc rrrolccLrlc is brrilI rrrr.posscssing lhe charactcrislics which are intrcrcrrt in llris shauc oimolccule, as djstjnct from thc atactic or syntliotactic ,"ofJ"i,t.,(see page 566).

Spirnirrg

Polypropylcnc fibrcs arc ntadc by cxlrusiorr of rrroltcrr polynrcr,followed by drawing to oricntatc thc ntolcculcs ,,,r,.t "ry.f, iL, ; i ithc.fi l f ln)cnls. Polymcr of high viscosity is spun, irr or.t", fo ot i^i,,opumunl trbrc propcrlics. Thc fi lantcnts arc coolcrl irr lr ir as tlrcvcnrelgc from ll lc spinncrcl, arrd arc collcclctl on bobbirrs.

.Bundlcs o{ f i lamcnts are hot-drawn, twistcd fln(l l)rckl.r}cd toprovidc nrultif i lamcnt yarns contrining, for cxanrplc, IO io SfXtf i la rnents o f 2 .2 to I ( r .5 d tcx (2 -20 dcr r ) .

T I A N D B O O K O F ' T E X T I L E F I A R E S

ln thc production of staplc fibre and tow, bundles of f ine fi la-nlcnls are combined lo form a tow containing hundreds o[thousands of individual f i laments. The torv is drawn and crimped,and thcn cut to an appropriate staple length.

S pinning and Processing Conditions

Polypropylcne crystall izes so rapidly that the undrawn li lamentsare highly crystall ine. In this respect, polypropylene di{Iers fromother synthetic polymers which arc mclt-spun, such as polyamidesand polycstcrs.

Thc unusually bigh crystall inity rcnders fibre-production verysensitive to conditions of spinning and subsequent proccssing, andpermils a fiuc degree of control over l ibre propcrties,

Thc lemperature at tvbich extrusiotr is carricd out, commonly80oC. o r more above the po lymer r r le l t ing po in t , and the con-ditions under which the fi lanrents are cooled, allcct the naturcirnd cxlcrrI o[ crystall inity. Rapid cooling or qucnching rcsults insnrall crystals, whercas slorv cooling allows Iarger crystals to fortn.

Thc dcgree of orientation achicved by drawing thc l i lamentsinfluences the mechanical properties; the Sreater the degree of

Stress-Sttain Curves lorPowder Co,

10 60ELONGATION (%)

I>olt propylc|c Fibrcs ^

MOOERATELY ORIENTED YARN

LOW ORIENTED YARN

578

Courtcsy Itercules

5't9

R : S Y N T I I E T I C F I T ] R E S

slretch, for cxamplc, the highcr the tcnsile strcngth and lorver lhcelongation.

The stretchcd libre nray bc furthcr conclitioncd by hcirt-trcitt-ment at temperatures bclow the softcning point. Hcrt-sctting, Iorexanlplc, aflects thc elastic recovcry, shrinkirgc charactcristics anclflex resistance of the nbre.

The effects of spinniug conditions and subscqueul. lrcatlrrcnIof the fibre are duc largcly lo thc way in which thcy inllucnccthe anorphous or icntat ion and cryst l l l i r re s t ructurc of t l tcpolypropylene. T l rc abi l i ty to contro l nrorpholoey dur ingspi r rn i r rgin th is way is used to ac lvantagc, pcrn l i t t ing thc prot luct ion o lfibres with a wider rangc of propcitics than-rvoukj otltcrwisc l)cpossib le.

StahilizatiottDcgraclation of polypropylcne tnkcs fl cc prinrnrily throtrghoxidot io t r , which is cncorr rngcd by hct t nnr l l ig l r t . Stnbi l iz r r t ionof polypropylcne is esscntial to conlcr light nnd hcat stability,and substanccs are commonly addcd for this purposc bcforc thcmolten polymer is spun.

Stabilizcrs are mainly conrpounds capable o[ (lctclivxtiogfree radicals which prornote the oxidative ch:rirt rcaction. Coru-pounds which are primarily U.V. absorbers rrc of little valuc irrthe stabilization of fibres (too !righ surfrce/voluure ratio).

Hcot Stability. Heat stabilization can bc providcd for poly-propylcnc fibres whicb enable thc fibrcs to rctain uscfulmcchanical propcrtics after cxposure to air lor cxtcndcd pcriodsal temperatures of, for examplc, 120"C.

A particular problcrn arises whcn polypropylcnc fibrcs nrccxposed to solvenls or aqLreous solutions for long pcriods, asthc stabilizers tend to bc removcd by extrrction. Rcpcalc(llaundering, for example, may result in thc gradual loss of sontcstabilizers. Spccial formulations lrave bccn dcvclopcd, howcvcr,to mcet this dimculty.

Liglu Stability. Thc usc of polypropylcnc fibrcs in applicationssuch ns car upltolstery requires that thc fibrc should bc ablc to

.. withstand long exposure to light at elcvatcd tcn]pcraturcs. li indingstabilizers for such applicirtions has bcen a clrallcnging problcnr.

Pigmcnted formulations havc bccn dcviscd. and arc uscd conr-merc ia l ly in carpets, uphols tery and rv indow channcl tabr ics.


For rcasons of cconortty, it is prelerablc to stabil izc poly-propylcne fibres to nrect lhe requitcments of specil ic cnd-ttses,rathcr than to use fibre which has bcen stabil ized to give adequateprotection in all applications. Manufacturers commonly market arange of polypropylcne fibres of difering stabil ity characteris(ics.

Pt{ocEsstNc

Scouri g

Thc size nray be renroved fornr the warp yarns of a polypropyleneor polypropylenc-viscosc or polypropylcue-cotton blcnd Iabricby an appropriatc scourirrg process.

Scouring may be carricd out in winch or j igger, using, Iorexanrple, a solulion containing 2-4 grans per l i tre of sodiurncarbonate and 2-3 grams per l i trc of non-ionic synthetic dctergent(c.g. Anionico SCL) for 45 minutcs at 80-95'C. Caustic soda(2 ml./l i tre conc. 36 Bi) may be used instcad o[ sodium carbouatc.

After thorough rinsing, l lrc fabric is dlied in the tenler frame,bearing in mind that the dried fabric can withstand 125-130"C.without suffcring danragc.

lVhilcning

Polypropylcne fibre itself does not rcquire whitening, but it isoften neccssary to rvhiten blends containing other fibres. Ingcncral, lhe processes conrmonly uscd for the individual f ibrcsof the blend rnay bc used. Fluorescent brighteners may also beaddcd.

Dye irrg

Polypropyler:e fibre, in its unnrodified fornr, is virtually undycableby any of the familiar dyestulfs and techniqucs. This factor has,more than any other, restricted the {ibre's progress in the appareland gcncral tcxti lc f iclds.'fhc

rcasons for polypropylcne's lack of dyeabil ity are twofold.On thc one hand, the parall inic chemical structure of the polymeris almost complctely non-polar; there are no centres of chcmicalafl inity by which dyestulls can be held in the fibre. On the othcrhand polypropylenc fibrcs are hydrophobic and almost cntirclyimperrneablc to watcri waler-borne dyestuffs cannot penetratereadily inl.o the interior of the l ibre.

580

D : S Y N T I I E T I C F I I } R E S

. Sincc polypropylcne fibrcs bccarnc lvailablc, cvcrv cllbrt lr irsl)ccr nrade. to dbvisc satisfactory rty"ing r""l iniqi,"r.;,r i;;;:;; i

illi",',li'rill,llil'",liii"0,'"*'"Xo.i,'"X"li,"",ll*il:ull:T"T",llpropy lcne, and do no t invo lvc char rg ing thc chcr l i ca l cor rs f i t i r t ionof tJre polymcr. Olhcr tcchniqucs rcqiirc clrcnricll

-r; i l l ; ; i l ;;;

or rnc porymer sl.ructurc in ordcr lo achicvc l lrcir clfccts.

l. Techniques bosetl on IJnmotlified polypropylanc

Couvc.ntional Dyeing processes

,u,t;i,.",1:'ir?:,1I:',lillil lT,:"::f :l.,iif ?iJ:":""i ::, ff ll:tion, but n-one, has provirJed a conrmercially ur"f,if "ofo,,i-ii i ig".Flat, pnle.shfldes with poor fastncss propcrfics, Ir. ;";;pj;:

il:::i:,:":fl [l"::"uf ili" 1,11i:1":ff ,il.,t lHh''i jl;"lifbc added slowly lo thc rcduccd li'ui," o."u,., ir,"'r;i,-u;;;;;;;;;;;'::i:li;::l:i'lij:".'rT,illll,:lilJ;.

:L';'ff liiel,:1111 nl'lli, "T,lilJ,ll',1,::1".#l',' ".;i'il:, tlfl ,-i']:rcsistant to washing or dry cleluing oi. ro iigfii.

,"i;;1'."..ii::";"J:J'. ;;llJl' ;.iffi'",fi [.,1. -]';:'"J' i.r'""T:l?,llpoinl of walcr. A dyc bath of rnoltcn u*0, for. "^^,",r1"1'*"i

iil-'"j1,,'Tll,"llj' il:,,'l"j:f,;i, .jij,"l;,lTllru;;.1i, ili:.:iircadily acceptable.

l'[ass ColouratiortPolyplopylcne, l ikc polycthylcnc,ad<ling suirabri pigmenis to' iire-irl:llJ"T"',r'l"jxfl ;T:.lil"J,l,i"liil{:,,'fl iillt,il]l i:i;[lJ':]" :1*lml I rul nl",llNiocrcases the productio' costs. Th; i*tr" ."rt

' i i.r'"";,' i i l;:;

proved too exorbitant in nracticcThe r r ra in d isadvantage bf p igrr rcr r tcd l jbrcs l ics in t l rc ncc( l tosrorc and market a widc rangc of colorlrs of cvcry gradc an<ltype o[ 1]bre. In recent ycarsl as cxpcricr." in riiJ ;;;;Ji;;;ano use ot p ignter) ted I ibres has grotvn, t l le tcc l tn i ( luc l i ls bccorr rc

58

_L' U' |'-] L' U U U L '' L I L L ' -

'l t t F. |l|� r t r F. F. I- f., F. n EI T A N D B O O K O F T E X T I L E F I A R E S

econonrically acceptablc, and thc pigntented l ibre continues tornake steady progress.

Atlt l ir ion ol Dye Reccplors

The dyeabil ity of polypropylene libres may bc improved bymixing dye-receptive substances with the polyrner before it isspun. Additivcs of this sort include (a) mctall ic compottnds, (b)polymers, and (c) misccllaneous low molccular wcight compounds.

A numbcr of f ibres are now on the nrarket, in which dycabil ityhas been increased by introducing additives of this type. Thetechniques used in dyeing l ibres of this lype arc specil lc to eachfibrc, and depend upon the nature of the additive.

2. Techniques basc(l on Chcnticalty-M odified Polypropylcnc

As the non-polar nature of the polypropylene molecule is partlyrcsponsible for the dycing ditl icult ics, au obvious approach lo thcproblem is to nrodify the polymer to improvc its dyc-receptivity.lr{any developnrents of this sort have been made, and modifiedpolypropylene fibres are now on the market. They includecopolymers made by incorporating a dye-receplive monomer intothc polymerization process, or by grafting dye-receptive segmentson to the main polymer chain,

Chenrical treatiuent of the nbre, such as halogcnation, has alsobecn used to improve the dyeabil ity of polypropylene by alteringits chemical structure.

These tcchniques, and others l ike them, bring about fundamen-tal changes by altering the chemical nature o[ the l ibrc, and thcyinevitably change the characteristics of the fibre too. Thesechanges may be small, lhe l ibre retaining its polypropylcnecharacteristics rvith only minor changes. They may, on thc otherhand, be so severe as to create a fibre in which the properties<ii l ler- significantly from those of a typical 100 per ccnt poly-propylene fibre.

Singci g

Polypropylene libre fabrics, in common with most fabrics madefrom synthetic f ibres, have a tendency towards pil l ing.'fhis nraybe avoided by l ight singcing treatments.

Owing to thc conlparatively low sotlening poil lt of poly-

582 583

B : S Y N T I i E T I C F I B R E S

p.ropylcnc fiblc, particular clrc is ncccssary in cttrying out thcsin-geing opcration. This is cspccially so in ihc casc of i"frrL, "i100 per cent polypropyle0c.

Singeing is carried out on the usual machincs, ancl onc or bothsides of tbe fabric rnay be treatcd. Thc tl istancc ancl inclinationof the flanle are set in the normal way, but singcing is usuallycarried out at high spced e.g. 140-t50 mcters pcr nrinutc. This isabout twicc thc spccd commonly uscd for iotton anrl viscoscfabrics.

Altcrnatively, the speed may be sct at ?0-g0 mctrcs pcr nrinutc,and the numbcr o[ burncrs rcduccd to lralf that usctl for co on.

Whcn light and loosc-wcavc fabrics arc trcatcd, i i is advisablcto wet tltem bcforc singci0g.

Singeing usually brings about sonrc supcrficial soflcningp-olypropyJcnc fabrics, causing sornc stif iening. .f.tr is

cnrielinrinated by passing thc fabrics throrrgh a cllcnrlcr.

Sy[(ltcl ic l lcsi

lrclt lntcna lo ltrDrovc Il lrn(l1-hc hand-of a labric may bc intprovcd and ils tcndcncy towtrdspil l ing reduced by trcaiment wilh spccial f inishcs con.sisting oisynthctic rcsins, usually in entulsiou fonn, ' l 'hcsc

l inislrcs arcespecially uscful in thc case of loose-wovcn fabrics and fabricsmade fronr ply yarns, such as Ioose-wovclr or twil l-rvcavcupholstcry fabrics.

Modcrn resin-bascd fiuishcs o[ this typc arc usually rtrlc toresist.rcmoval by laundcring an<t dry-clcaning, and thcy ntay bcconsidcrcd as pcrmancnt finishcs

Crcascproof Trcnlnrc|lls

Fabrics .of 1.00 pcr ccnl polypropylcnc l ibrc cilInot bc trcatcd

cltectrvely wtth creascproof rcsin, as t.hc fibrcs arc so incrt thiltthe resins are no! f ixcd pcrnrancntly to thcnt.^. Fabrics made from polypropylcnc fibrc blcn<lcrt with ccllulosicllbres, howcver, Inxy bc crcascproofcd by nrcans of rcsins rvhicltact upon the ccllulosic componctrls.

Owing to . thc .compara t ivc ly low so f tc l ing po in t o f t l r c po ly_propyrcnc tlbrc. rt rs ncccssiry lo sclcct l lnishcs tlr l ( lo n(' l rcquircheatirU lo tcmperaturcs abovc 130.C.' l.his rcslricts thc sclccfiotrcousiderably, and many of thc ntost efcctivc of thc crctsc.proofing finishcs cannot be used.

o lbc

II

I IANDDOOK OF 'TEXTILE T . ' I t r R ES

W|lterproofing

Acrylic Resin Finishes

Fabrics of I00 per cent polypropylele may be waterprooled bycoaling with acrylic rcsins dissolved in organic solvenls, or in thefornr o[ aqucous cmulsions. This rcsults irr an impcrrneablc fabric,and is not recommcnded for apparel applications.

Silicone Finishcs

Polypropylene fabrics may be given a high degrce of rvaterrepellency by treatment rvith sil icone Iinishes. These have thcadvartagc of leaving the fabric air-permeable.

Cltrotnirrttt Co:nrplc.res ol Stcaric lcid

Finishcs bascd on the chromium conrplexes of stcaric acid nraybc uscd to inlpart good watcr-repellcncy to polypropylcnc fabrics.

Permrnent Antistatic Finishing

For certain applications, such as laboatory coats, overalls, etc.,it is neccssary to providc an antistatic f inish that rernains ellcctivethroughout the l ife of the garment. A number of products areavailable for this purpose.

C:|lcndcring

Calendering must be carried out very carefully, bcaring iu mindthe relatively low softening point of polypropylcne fibres. lt isrecommended that the temperature slrould be no more tlran 90"C.,and the cylinder load 15-20 tons. It is possible to use 30-40 tonson the silking calcnder.

Fornr Ilrckiflg

Foam-backed fabrics nray be made satisfactori ly lrom l00 percent polypropylene fabrics, and also from blendcd polypropy-lene/cotton and other fnbrics.

The.ppcedurcs used for applying polyurethane foams aresimilar to those used with fabrics made from other fibres. Acrylicresins may be used as adhesives, or the foanr may be applied byfusion techniques.

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IaI

ID : S Y N l l l l l ' l r c l : l t R e s

I\{ouldirrg

Polypropylene fibrc is thcrmoplastic, softcning at about 150.C.and mcltitrg at about 160-i70"C. Fabrics colsistiug rvholly or irrpart of polypropylenc fibrc nray bc mouldcd untlcr propcr contl i-l ions o[ t irnc ancl lcnrpcraturc into fl lnrost any tlcsircd slrlpc.-fhis

mouldabil ity nray bc uscd in innumcrablc npplicatiousrvhcrc a fabric is rcquircd in t thrcc-dirncnsional slrnpc, such lrsbrassilrcs, hats, handbags, inncr and outcr l inings lor lrrggrrgc,pancls for furniturc and car upholstcry.

Fibre Content antl Fubric I'ype

A nrininrum of 70-80 per cent polypropylcnc fibrc in tlrc fablic isrccolnmended in ordcr to cnsurc good mouldabil ity. ' l 'hc

fitbricsnray bc tnadc from staplc or continuous fi lanrcnI yarns, an<l nrlybc jn almost any typc of weavc, Vcry dcnse flbrics rcquirc highcrtcnrpcralurcs than lhinucr fabrics.

Non-wovcn fabrics rnust lrrvc lrigh nntl cvcrr ly-tl islLibtrlctlstrength properties in nll dircctions.' l 'hc nrain problcnr prcscntcdby non-woven fabrics is thc rcadincss with which thcy tcrr duringthe hea(ing cyclc, duc to shinkagc. Chcmical bonding agcnts canoftcn overcome this dil l iculty.

IIcat-Sctling

In common wilh other thermophstic f ibrcs, polypropylorc fibrcsand fabrics can bc hcat-sct against subscqLtc|rt shrinkilgc anddeIormation.

A tempcrature of 130"C. is thc maximunr practiclbly-usablctemperature for hcat-setting. Fabrics sct at. lhis tcmDerrturc wil lresisl. sl)rinkxgc in boil ing wllcr, and :rrc s(lblc rrl) t; 120.C.

Blended {abrics containing nrorc lhan 30 pcr ccnt polypropylcrrccan be hcat-set, (hc cllcctivcncss increasing with thc prol)ortionof polypropylenc in the blend.

Plcats and crcases may bc hcat-sct in polypropylcnc fabrics orblcnds, and these fabrics nray also bc mouldcd into thrcc-tl inrcn-sional shapes (sce abovc). Thcy may bc calcndcrcd ancl cnr-bosscd to givc pcrnt ncnt cllccls

Hcalsettirg inrprrts rcsistance to wrinkling during wushing.

Bonding

A variety of adhesives may be uscd in bonding polyolcfin firbrics

585

,F-F.tfFJJ.r F. F t F, F f=, n F, n" I


and yarns, including (l) contact adhesivcs containing volati lesolvcnts, (2) hot mclt resins, and (3) cpoxy compounds.

STITUCTURE AND PROPEITTIES

Molccular Structurc

Unlike the natural libres and most of the important synthetichbres, polyolefins bave no polar groups. Prior to the devclopmentof isotactic polypropylene, it was considered that polar groupswere essential to the production of textile fibres of high strength.'fhey provided the forces wlrich held the linear molccules togethcras they lay alongside ons another in the orientated fibre.

The presence of polar groups in a linear molecule does makethe manufacture of high-strength fibres possible from polymersof relatively low nrolecular weight. Polyamicles yield strong fibres,for example, when the rnolccular weight lies betwecn 10,000 and30,000.

In polypropylene, it is crystallinity alone that provides tensilestrength by preventing slippage of the linear molecules. Andhigher molecular wcights are necessary to obtain the necessarystrength. Polymers of molecular weight greatcr than 50,000 arcnccded, for examplc, to eliminate intracrystalline llow, corres-ponding to tenaci t ies of a t least 44-53 cN/ tex (5-6 g/den) .

Monofilanrents with tenacities above 88.3 cN/tex (10 g/den)require polymers of molecular weight greater than 100;000.

The average molccular weighls o[ polypropylenc used in fibremanufacture arc commonly higher than 200,000. Lligh-densitypolyethylene fibrcs, by contrast, have molecular weights in theregion 50,000 to 150,000, and low-density polyethylene 20,000 to25,000.

The linear molecule of isotactic polypropylene is thus, onaverage, twice as long as a linear molecule of high-density poly-elhylene, and more tbrn l0 times as long as the nrolecule oflow-density, branchcd polyethylene.

Dcgrcc of Crlstxll inity

The crystall inity of a polypropylene fibre, rvhiclt has such auimporlant infiucuce on lcnsilc strength alld other nrcchanicalpropcrtics, is controllcd prinrrri ly by thc uaturc of lhe polynreritsell. The dcgree of crystall inity attainable dcpends upon the

586

B : S Y N T I I E T I C F I I } R E S

average nrolccular wcight and nrolccullr wcighl dislribUtiou, andon thc content,of isotlctic polynlcr, lt nrity vnry bctwccn twoextremes, represented by a con)plclcly nnrorl)l)ous i lt ctic poly-propylene on the onc hand, to thc 100 pcr ccnl crystall inc isoiacticpolypropylene on the otlrcr. Thc norntal "o.nlnr"ri inl poll,nrcr hasa degree o fc rys ta l l in i t y o fabout ( r0 to 70 pcr ccn t .

^ The degrce_o[ c rys la l t in i t y o f a po lypropy lcnc l ib rc i s in -

IUenccd also Dy thc lrcatnlcnt to which tlrc l lbrc is sutrjcctcdduring procesing. Stretching and hcat-trcatnrcnt may rtlcct thcway in which the l incar nroleculcs arc packccl into l l icir ordcrctlcrystall ine pattcrns.

Thc high degrec of cryslalt inity achievccl jn isotnclic nolvDronv_lcle fibres is reflcclcd in thc high strcngth ald stit i lcss, rrirt l i t iclow elongation of thc l ibres.

lsotacticity Indcx' fhc

contcn t o [ i so lac t i c po lypropy lcnc is rnc ls r r rcd l l v cs l in rn t inuth:, arlto.l lnt of rcsiduc rcnraining aflcr cxtmction of ihc polyrrr"iwrrn Dotjtng n. hcPtirnc; i l is cxprcsscd as l lrc isota..i.. i ty itular.Connrercial polypropylcnc has an isolacticity ina"x of ov"r qOpcr cent.

FiDe Struc(urc a d ApJ,enrfl ccPolypropylcnc fibres are produced as colourlcss Ii lanrcnts, nnd irra range of pigntented shadcs. They are srnoo t h -su rlhccrl ariria re son lewl )a t waxy in : lppcara ce .

' l ' he f i lan tcn ts a rc o l . t c r r o f

round cross-scctior), but thcy arc nlso proclrrccd in a varictv oIotlter cross seclions for spccil l appliclt iorrs. Dianrctcls l ic iorrr-r l lo l l l y Detwcen 0 .02_0.5 r r r r r r (0 .000g_0.02 i r r ) , bu t hc i l v ic rnronofils are procluced for use as bristlcs.

'fensile StrcnSlh

Polypropylcnc fibrcs arc produccd in a varicty of typcs of <li l lcr-r rg l cn i l c ' t t cs dcs igncd to sU i t vary ing nr i t rkc t rcqUi rc rncDts .. Most applications are adequatcly icrvcd by fibrc of rrrctl iunrtenac i l y , -and commcrc ia l s tap tc and con l inubus f i l n lcn t van lspJoduccd. to r ge t le ra l t cx t i l c uscs l lavc tc l tac i ty 2 ( r .5_44.1 cN/ tcx( r - ) -

_g /den l ; t cns i te s t rc r )g th 2 ,450_4,200 kg /c l r2 1J5 ,0b0_60,000 lb / inz ) .yarns reach ing 80 cN/ tcx (9 g / t l cn) x rc r r ra t l c . For spcc i : r i

587

I { A N D D O O K O F T E X T I L E F I D R E S

purposes , yarns o f tenac i ty up to l l5 cN/ tex (13 g /den) a reproduccr l .the other haud, does not need to be of very high tensile strength.High resil ielcc is a more desirable characteristic, and fibres oflower tenacity are produced for this type of application.

Knot and loop streogths are usually some l0-15 per ccnt lowcrthan Lhe strength o[ thc straight l ibre.

l i lorrgation

Contmercial polypropylcne monoRltmcnls have an elongation atbrcak in thc region of l5 to 25 per cent.. Multif i lament yarns arein thc rangc of 20 to 3(l pcr cent, and staple l ibre 20 to 35 pcrcent .

lilastic I'ropcrlics

The elastic properties of polypropylenc fibres, in common withother mcchanical properties, may be varied over a wide range bychoice of polymcr and processing conditions. Fibres can be pro-duced to meet the requirements of specific applications withrcgard to elastic properties.

I{igh Tenacity Fibre

Thc elastic recovery properties of commercial high-te[acity f ibresare excellenl, and similar to those of nylon. Immediate recoveryafler l0 per cent elongation is about 90 per cent with virtually nopermanent set.

Metliwn Tenacity Fibre

Init ial Modulus.fhe nrodulus of elasticity on l0 per cent exten-sion is in the range 263-795 cN/tex (30-90 g/den) for nrultif i la-nrents, and 221-353 cN/tex (25-40 g/den) for staple.

Ektstic Rccovery, Elastic recovcry at 5 per cent clongation is90-98 pcr cent for mtrlt if i lanrents and 90-95 per cent for staple.

Lov Tenacity Fibre

Yarns of tenacity 17.7 cN/tex (2 g/den) are made under specialcondil iolls of hcat-trcatmcnt at high temfjerature. Thesc yarnsshow a 95 pcr cent irnmediate recoyery front 50 per cent cxten-sion, and conrplcte rccovcry after 5 minutes.

588

F1-'Y1--1--L-I '[ ' I ' I ' I


Crecp Clnractcristics

Cold flow or irecp churactcristics oI polypropylcnc arc satisfac-tory, and. a great inrprovcment on polyctl iylenc, Uut,fo nor i"o"i,ll",-.-,1lglro ser by potyamidc-or polycsrcr librcs. potypropylcncltDrcs wt

undergo cold flow of up to 0.5 pcr ccttL of t irc oricinalierrgth whcn subjccred ro r loatl of lJ.2 cN/tcx f f .S s/(fc,ri r.;i'iinours at roonl tenlpcrature_

l;lcx R(sistqnce

Exccllent.

Spccilic Gravity

As in.the case of polycthylcnc fibrcs, thc spccific gravity of nolv_propyrcne varies wilh thc dcgrcc oI crystall inity. Amorplrorrs i lolv-propylenc has a spccific gravily o[ 0.g5; conrmcrcial nbr"s ai" iutlrc rlnge 0.90-0.91, and highly crysta inc fibrcs rcach 0.92_0.94.

l 'olypropylcnc l ibrcs arc tltus (hc l iglrtcst. of all conrrrrcrcinilcxtilc fibres, even rhe higtrty crysra inc- fi brcs t"i"g rieiii"i it,;,,a l l bu l po lyc thy lcne.

Dltcct of Moisturc

Polypropylene is a parafl ' inic hydrocarbon, and it docs not absorbwatcr. Thc nroisture regain of polypropylcnc nbrcs is so smtilas to be insignil icanl, and walcr has no cfiect on tcnsile strcnglltand other ntcchanical propcrties,

Water docs not cause auy noticcablc dcgradation irr nolv_;>ropylene fibrcs. Fibres subjcctcd to boil iug *nt". o, ,t"n,i, lo.long periods show no loss o[ slrcnglh.

Thcrrnal froper(ics

Solre ing Point; Mclti g PoinlThc^ solteuing _poiot of polypropylcnc fibrcs is in lhc rcgion of150'C., anrl thc fibres mclt ar l60-17o"C. .l-hc

soltcnii j aurlmelting points of spcci{ic polypropylcncs are clctcrnrincd 5y thcnature of the polymcr and by thc way in rvhich crystall inity hasoecn tn uenccd dunng trcatmeut of thc fibrc aftcr spinning.

Efect oJ Lotv Tern perature

Polypropylene fibre retains its f lcxibil i ty to tonpcrnturcs oI

589

| : - - | : - - - - - - r - - . n nI I A N D B O O K O F T E X T I L E F I B R E S

-70"C. or lowcr, It docs not rcach thc rcntalkablc standard sctby polyethylene il l this respect, but its low tenrperatur€ Ilexibil i tyis excellent for most practical purposes.

EIJ cct o J H igh'I ' etn pc rat ute-lhc

rnechanical prot)erties of the fibre deteriorate with increasingtcmperature bclow the softening point, but polypropylene per-Iorms bctter than pol,ethylcne in this rcspect.

Shrinkage Properties

Shrinkage of polypropylene fibres depends greatly upon thetrcatment ihe frbre receives during proccssing, In boil ing water,monofilaments may shrink as much as 15 per cent after 20minutes; mull i l i lament and staple yarns rnay shrink between 0and l0 per cent .

FlanunabilityPolypropylene is a hydlocarbon, and it wil l burn. On being cx-posed to a flame, however, the fibre melts and draws away fromthe flame, extinguishiug itself.

Polypropylene fabrics exceed tbe requirements of Class I ofthe ASTM Standard for texti le fabrics. Tcsted according to8.S.2963, they are self-e>.tinguishing and therefore of low llamma-b i l i t y (B .S.3 l2 l ) .

Construction, additives, f inishes and the presence of other fibreshave a considerable influence on the burnirg characteristics ofany particular fabric or structure.

For the purposes of f ire insurance, polypropylene fibre is in-cluded in tl)e sarrc class as n,ool.

'f herntal CottductivityThc following table l ists tbe tbermal conductivit ics of polypropy-lene and other important texti le Rbres:

r tore

PolypropylenePVC fibreWoolCellulose acetateViscoseCottoo

T lrcnnal Cottductivity(relative to air 1.0)

6.06.47.38.6

I 1 . 017.5

590

D : S Y N T U E T I C F I B R E S

Polypropylenc has thc lowcst thcrmal conductivity of all conr-mercial fibres, and ir this rcspecl is the'warmcst'librc of all.

Etfcct of SuDlight

Like polyethylcne, polypropylcnc is attackcd by atmosphcricoxygen, and the reaction is stimulated by sunlight. Polypropylcnefibre wil l deteriorate on exposure to l ight, but it may bc protcctcdc{Ieclivcly by mcans of stabil izcrs.

Chemicrl I'ropcrties

Acitls. Excellenl resistance, similar to polycthylcuc.

Alkalis. Excellent resistance, sinrilar to polycthylenc.

General

Polypropylcne is inert to a widc rangc of chcnricals. lts rcsistrnccand susccptibil i t ics arc similar to thosc of polycthylcnc (scc pngc554), but its high crystall inity tcnds to nrakc it morc rcsistantthar polyethylcnc to those chcnricals rvhictr dcgradc olclin fibrcs.

Eflcct of Org{nic Solvcnh

Excellent resistance, gcucrally similar to polycthylcnc. Thcrc isno known solvent for polypropylenc at room tcmf,craturc.

Insccts

Polypropylene cannot bc digcstcd by iDscct and rclatcd pcsts, suchas white ants, dernrcstid bcetles, silverfish and moth lurvac. polv-propylcne fibre is not l iablc to attack unlcss it bccorncs a barricrbeyond which the insect olust pass to rcach an objcctivc. ln thiscase, the insect may cut through the fibre without digcsting it.

Micro-orgnnisms

Polypropylene fibre will not support the growth of mildew orfungi. Some micro-organisms, lrowcvcr, rnny grow cvcn on thcvery small amounts of contalninaDts which lnay bc prcscnt on thcsurface of libres or yarns in usc. Such growth has no cflcct onthe strength of any nraterials nradc from polypropylcnc fibrc.

Elcclt ical Propcrl ics

Polypropylene is an exccl lcnt insulal ing matcrial, and sincc thc

5 9 1

' I N D B O O K O F T E X T I L E F I D R E S

absorption of nroisturc is so cxtrenrely small there is l i tt le or nochangc in thc elcctrical propcrties at high hunridit ies - an im-portant point in eleclrical applicalions.

Cocll icicnt of l ir icl ion

Polypropylene has a rclativcly high coeflicient of frictionagninst snrooth surfaces, particularly rnetal or porcelain. Thc co-cfi iciclt of friction of yaln againsl, for cxarnple, a yarn guidcdccreases with jncreasil lg tcnsion.-l 'hc

coeflicient of friction ngainst a matt guidc, i.e. a guide witha discontinuous surface, is much less tlran against a polishedguide, owing to the smaller actual area of contact between tbeyaflr and nratt surface.

Coeffcicnt ol Filamenl to Filanent Frictiotl

Static friction (avcmge speed 2.5 crn./rrrin.)Dynamic friction (average spccd 95 cnr./rnin.)

Olltcr lropertics

I Iandle

Polypropylene has a much less waxy feel than polyethylene, andits fabrics havc a pleasanter handle.

Etrvirorurrct al Stress Cracking

Po lypropy lene does no t show any tendency to 'c raze 'o r deve lopsurface cracks when sublected to strcsscs in the presence of deter-gents or other substanccs.

Idcntilicatio[ of PolypropJlcrc liil.rrc

The following tests wil l help in the identil ication of polypropylenef ib res :(a) Apperu'ance

Polypropylene seen through the microscoDe is smooth andfeaturelcss in appearance. Circular, tri lobal and tlclta cross-scction fi lanrents arc comnronly encountercd.(b) Burning Test

When a flamc is brought up to a polypropylcne yarn, lhe fibrcsmelt and retracl. A bearl of nrolten polymer is formed, wlrich on

o.32-0.420.?9-0.40

592

. lI

' l I r I ' I r I r I r-l '--1

B : S Y N T H E T I C F I B R E S

I'olyptopIlc,rc

continued contact with the source of hcat wilt burn with a bluc-and-yellow flame similar to that of a candlc. A charnctcrislicodour.is givcn oll wlren the burning malcrial is cxtinguishctl.

(c) DensityPolypropylcne and polyclhylcnc arc thc only tcxlilc fibrcs rvhich

arc lighter than watcr, and this is tho basis of onc of thc nlostuseful methods of identification.

A tcst sanrple is cut into lcugths of { inclr (6 nrur.) or lcss,tclscd irto individunl fibrcs and stirrcd into watcr containinc !rl i t t lc wct t iog agcnt ( l g . / l i t re L iss pol N) . I f thc smr l l p iccc i o tfibre float, thcy are almost cerlainly polycthylcnc or polypropy-lenc. These nray be distinguishcd by thcir mclting pointii poly-propylcne lics in the region 160-170"C., and polyctlrylcnc in tlicregion ll0-140"C., dcpending on thc typc of polyrncr.

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T I N D A O O K O F T E X T T L E F I B R D S

I 'OLYPI {OPYLENE FIBITES IN USI :

Gencral Characleris(i(s o[ Polypropylcnc Fibrc Goods

Initially, polypropylene monofilamcnts made their way into appli-cations which had already been pioneered by polyethylene. Theyoflered highcr streugth, increased toughness, resil ience, abrasionresistancc and crecp resistance, and a higher mclting point; thescproperties werc all ied to the water-resistance, chemical inertnessand other properties tbat had enabled polyethylene to compete ina range of applications.

Polypropylcne monofilaments on this basis, were soon en-trenched in a number of fields where they competed very eflec-tively with other l jbres; thcse fields included ropes and cordage,fishing nets and twlnes, f i l ter fabrics, protective clothing and thel i ke .

With the introduction of l ine-denier multif i lament yarns andstaple fibre, thc range of poteutial applications for polypropylenelibre was extended into the general texti le and apparel f ields. Thisbrought them into ccmpctil ion with established natural andsy[thetic f ibres in applications where the shortcomings of poly-propylene fibres often place them at a disadvantage. Despite themany attractive characteristics of polypropylene fibres, less dcsir-able properties - such as dyeing diff iculties and relatively lowmelting point - have lended to l imit progress.

Processitrg Belnviour

Polypropylene libres have a fi lamenl-to-fi lament coeflicient offriction higher than that of any other texti le l ibre. This, in com-bination with crimp stabil ity and low static charge accumulation,makes for excellent processing characteristics. Polypropylenelibres blend easily and ellectivcly with otlrer texli le nbres.

Covering Power

The lorv specil ic gravity of polypropylene fibre gives it a coveringpower which is, weight for weight, greater than that of any othertexti le f ibre. This has been particularly helpful in the developmentof polypropylene blankets, upholstery, carpet and apparel fabrics.

'l- lrcrnnl Insulatiott-fhe

thernral insulation characteristics of a fabric are determincd

s94 595

B: S YN, r l l E . I . l C F lnRr ,sla rgc ly by t l rc anrounI o ( t i r cn t r ppcd in thc f : rb r ic . . l .hc l l r c rn ra lconductivity o[ polypropylcnc l ibic is, lrowctcr, I"*;; i t;,;; ' ; i ; iot othcr t lt jrcs, and irr lhis rcspccl polypropylcnc is lhc ,wanlcst, Ore ln commcrcial usg-Crease Rcsistance

The abil ity of a tcxti lc labric to rcsist crcirsc Iormatiorr durirrtuse is inlluenced by the physical naturc of lhc nbrc itsclf. Ir l th;casc of polypropylcnc fibrc, this charactcrislic varics with thcmolccular weight of thc polyncr, and with thc conditions o[sp-inning and dra.,ving. Polypropylcnc yarns arc protlucccl iuwhich the crease resisl. ing propcrtics are at optinrunl valuc forapplications where this is imDortant.

In gcneral, the crease-resistincc of polypropylcnc Jibrcs is ofthe same order as that of wool. Uniike wobi, howcv"r, poly_propylene fibre docs not losc its high crcase-rcsistancc whcn wct.Shrinkage

By.controll ing the condil ions of proccssing, lhc shrinkngc chirrac_tcristics of polypropylene yarns may be varicd ovcr a considcrablcrange,

Shrinkage of polypropylene yarns is quitc low under thctusual conditions of Iabric scouring and dyeing. Speciol carc mustbe .taken, however, whcn high-lenrpcraturc hnislt ing treatmcntssucn as rcsln curing i lrc uscd. Shrinkagc may bc lrigh i lt clcvatcdlemperatures.

This shrinkagc caused by high tcmpcraturcs is not progrcssivc,and polypropylcnc fabrics nray be hcat-sct. In cornnron witlrother -syntbetic f ibres, hcat-treated polypropylcnc yarns whichhave been allowed to shrink and Ueconic srribit izc<] at a givcntcmperature are essentially stable to subscqucnt trcatmcnt up toth is tempera ture . Th is p r inc ip le i s usec l in p rov id i r rn d i rncr rs io r r r lstabil ity to [abrics nrade frorn polypropylenc fitrrcs.-

. .Fabr ic . shr inkage ur rder cornrncrc ia l c l ry -c lc r r r i r rg conr l i t io r rsw l rn perc l l lo re thy tene tends Lo be cxccss ive . . l l r i s l i rn i ts t l t c usc o fpo lypropy lene i l some tcx t i le app l i ca t ions .

Higlr-shrinkage polypropylcnc fibrcs may bc prcpnrcd by lhcusc-of.appropriatc proccssing conditions. f ibrcs of-this typc arcuseful in the plodrrctiorr o[ ccrtain typcs o[ tcxtrtrcd and-bulkctlyarns. Jn blends, thc high shrinkagc o[ a polypropylcnc corrrpo-ncnt of Lhis typc may lrc used to crcatc bulkcd or pirckcrctl cfc:ctsrn yarns and finishcd fabrics.

ilI

I I A N D B O O K O F 1 ' S X ' I ' I L E F I D R I ] S

Cree p

Polypropylenc yarns generally cxhibit nrore creepor nylon yarns, but t lte amount is so sntall thalpractical signil lcance. It is usually appreciablynormal extension of the yarlr under the load.

than polyesteril is rarely ofless than the

Where a rope or other conslruction has to withstand a contin-uous heavy load, it is usually dcsigncd so that the averagc loadingis qui te low, c .g. 4 .4-8.8 cN/ tex (0.5- 1.0 g/c lcr r ) . 1 'h is is ncces.s i ta ted by safety considcrat ions. UIdcr thcsc condi t ions. theef fcct o f creep is vcry srnal l .

Din(nsionul StabilityDinrensional stability of polypropylenc fabrics is excellent, andthe water-rcpcllcncy of the fibre enablcs it to retain its Irighstability through repeatcd launderings. Polypropylcnc fabricsretain thcir shapc in changing conditious of nroisturc and hunrid-ity, and on lhe strength of this stability lhcsc [abrics lound aready market in upholstery and industrjal fabrics, laundry bags,seat belts and protective clothing. ln such applications, poly-propylene fibrc provides high strcngtlr, low elougation, toughness,rcsilience and abrasion resistance which do not chansc undcrnormal conditions of use.

Abrasiotr ResistanccPolypropylene fibres havc a high resislance to abrasion when dry,and cvcn greatcr rcsistancc whcn wet. The abrasion resistance of ablend containing polypropylene fibre increases in proportion tothc amount of polypropylene libre in thc blcnd.

Abrasion resistance is of particular importance in applicationssuch as carpels, where the ability to withstand wear is esscntial.In con'rmon with other mechanical properties, abrasion resistancenray be influenccd by the nrolecular weight of the polypropylene,cross-section, and the conditions of spinning and processing.Fibres may be produced with optimum a6rasion

- resistancl

characteristics for special applications.

Felting BehoviourPolypropylene fibres, like nrost other synthetic fibres, do not felt.In blcnds with wool, polypropylene reduccs the tendency to feltin proportion to the arr,ount of polypropylene fibre jn the blend.

596

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I : S Y N l l : r I C r r t u R E s

ll/ osh qntl ll/ utr C I nrac tcrist ic.sPolypropylcnc fibrc is unusually rcsistant to soil ing.

-l-his is

in0trclccd in thc nrain by two factors:

(^) Electrcstdic AItt 0ctiotlPolypropylcne fibrcs shorv Iitt lc tcndcncy to accurrrultrtc clrirr.gcs

oI static electricity throLrgh friction duiing usc. .t.hcy do iot

atlr ct dust nnd dirt to thq cxtcnt thirt nlosl. othcr syntltctic f ibr.csdo.

(b) Chenical Inert cssPolypropylerrc does not rc ct chcmically with thc substanccs

cncoulltcrcd in gencral usc, nor is i l . attackcd by contnron solvcnts,grcascs, oils, ctc. Jt. js not rcadily stainccl, thcrc[orc, and suchstaining- as docs tf lke place is conrnronly supcrticial. ' . l .hc

sfaiiri s hck l in thc in te rs l i ccs o f thc fabr ic by cap i l i l r y n l t r l c t ion , lndis rcadily renrovcd by lrrLrndcring or rlry clc:rrring.-

Ilourl ond D roping ClrrructeristicrHand arrd_ dr ping chtt cteristics dcpcncl grcatly <lt l lhc rvcavingrnd finishing ol fabrics.

Flct ResistenccFibres havc good [1cx rcsistance and rrrotlcratcly gootl rccoveryI ro r r_bcr rd ing , and lhcsc pr .opcr l i cs sc rvc lhc r r t w-c l l in " l r rn " tsr ,nd t toor covcr ings . fcx t r r rc ( l f i l i rn rc t r t anc l bu lkc t l s t : rn lc v i r t l shav-e rnadc good hcadway in thcsc and othcr pilc fabric.s.

'

High flcx rcsistancc couplcd with cxccllcrit loop- anrl knot_s t rcng lh a rc i r ) tnor ta | | t i t r thc p roduc l ion o f k t r i l t c i l goods , an t lpolypropylcnc fibrc has foLrnd many applicrtions such is srvtiatcrscardigans, swirttwcar and undcrwcar.

Pleal Pennanence

Plcats may. bc ltelt-set in polypropylcnc fabrics, lrrrd tl lc l) lci l lssnow exce ent relcntio . A blcnd of polypropylcnc fibrc (60 pcrccr t ) and woo l ( . . |0 pcr ccn t ) w i l l ta tc p tca t iwc l l l t t rcy , i , ry ' l r ctroncd into thc I bric al I40.C. In most cirses, plcati nray l.rcpresscd into polypropylcne If lbrics at 130"C., wtricl i givcs a bctrcrnrargin o[ safety, especinlly in fabrics of l0d pcr *ni p"ffpi.py-leuc fibre

H A N D A O O K O F T E X T I L E F I B R B S

Clrcapttcss

Pcrhaps the most important of all the features of polypropylcneto bc taken into account when assessing jts use for a particularapplication is its cost. Polypropylene is potcntially the cheapest ofall synthetic f ibrcs, and this must give it a tell ing adyantage incompetit ion with other Iibres where lecbnical dil lerences aremarginal.

lVaslring

The resistance of polypropylene fibrcs to a wide range oI cherni_cals including acids, alkalis and normal texti le bleaches, enablesfabrics to withstand all the chenrical conditions commonly en-countered in waslring and laundering. In addition, the fibre doesnot absorb moisture, antl it does not felt.

Wasbing may be carricd out without dil l iculty, using tenrpera-tures up lo 100"C. It is preferable to use warm water at about40"C., witb soap, soap powder or detergent. The goods should berinsed rvell, and a small amount of detergent or softeniog agentmay be addcd to thc final rinse to increasc softncss of handleaod antistatic properties.

Drying

Polypropylene libres do not absorb moisture. and fabrics wjl ldry quickly at room temperature. Spin drying or drip drying arepreferrcd; tumble dryinu should be used with great care to ensurethat the goods tumble freely.

Ironi g

The soltening point of polypropylene fibre is lower than that ofmost other commercial texti le apparel f ibres, and ironing must becarricd out with care. A steam iron may be used, or ariordinaryiron in conjunction with a damp cloth. If ironing is done withouicither steam or cloth, a low setting sbould be used, bearing inmind that the fibre softens at about 140"C.

Dry Clcaniog

Polypropylene goods nay be dry cleaned satisfaclori ly with tri-chloroethylene or white spirit ai temperaturcs below 50"C.; poly_propylene behaves in this respect l ike wool. perchloroethylenc

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R : S Y N T I { E T I C F I N R A S

is rrot rccomnrcrrrlcd as a clry clclning agcnt, as it nrty l lcct lhcd i rncns iona l s tab i l i t y o [ tbc f rb r ic .

trnd-Uses

Ropes

fhe principal rcquirements o[ a fibre to bc uscd in making ropcsfor marit ime, agricultural and industrial usc includc thc following:

(l) lr igh strength, wet or dry(2) resistance to repeated loading and ficxing(3) resistance to abrasion(4) minimum waier absorption(5) l ightness(6) rcsistance to weathering, l ight, seawatcr, chenricals, solvcnts,

micro-organisms and othcr potentially dcgradativc agcntsencountercd in normal use.

' lhis is a formidtblc combination of propcrtics, nnd fcw conr-

mercial f ibres arc ablc to satisfy all rcquircnrcnts to a highdcgrcc. Polypropylcnc fibrcs compctc favourably with othcrfibres, natural and synthetic, in this respect, and thcy havc foundan important outlet in the field of rope manufacturc.

Polypropylene ropes wil l f loat in water, and this can bc a sig-nificant advantage in certain circumstanccs. It rcduces the losscswhen ropes fall overboard, for example, during fishing and othcrmarine opcrations.

Fishing Cear

Amongst lhe most important propertics of yarns to bc usctl inlishnets, trawls and lincs are:

(a) high sl.rength, wct and dry(b) great toughness(c) low weight(d) low moisturc absorption(c) dimensional stabil ity(Q resistance to degradation by weathcring, l ight, scawatcr,

chemicals, solvents, micro-orglnisrns ancl othcr potcnliallydegradative agcnts encountcred in normal usc.

This combination of rcquirernents is csscntially sinri lar to thcrequirements l istcd in thc scction on ropcs (abovc), In thc p:lst,

JI I A N D D O O K O F T E X T I L E F I B R E S

co l ton tn ( l r r r iu r i la nd a fcw o thcr na tur i t l f ib rcs havc . as in thcc lsc o [ ropcs , bccn usc t l Io l r r r l k i r rg f i sh ing gcur . l . l r c i r i l to r tco l l -rr)gs wcrc.slrcll, howcvcr, that synlltctic f ibrcs matie rapicl progrcssin th is f i c ld , and ny lon in par t i cu la r has becn ab le to tak i o ic r alalgc plrt of the production of f ishing gcar since the end o{World. War I I. More rcccntly, nylon hns becrr joincd by polycster,polyelhylene and polyvinyl alcolrol l lbres wlrich have'ail secureja place in thc world nrarket for f ishing gear.

. In I961, polypropylcne was introduced into this ficld, ancl ithas madc rapid progrcss in direct colnpetit ion with its establishcJsynt l rc t i c f ib lc r i va ls . By 1964, to r cxanrp le , lhc p rodr rc r ion o fpolypropylcnc ncts in Great Britain cxcccded the overall total o[nels produced frorr all othcr syntlrctic f ibres.

Thc rcasons for the rcady acceptance of polypropylene in theproductiou, of f ishing gear are to be founcll inits unique corn_bination of propcrtics, and in its low cost.

. i\ ' lany polypropylcnc fibrc l)roduccrs are now nrrrkeliug lt igh_

tcnrcity polypropylcne Inultif i l irmclt yarus lor use in tltc p-rotl ic_lion, of f ishing -q_ear. - l 'hesc y:rrns commonly provide a ienacitvin t l l c rcg ion o f 7 l cN/ tex (8 g /der r ) , and e i te i rs ion in the rcg io i lo f 20 Dcr cc t r t -

lvlonofilamcnt. yalns may also bc uscd with advanlagc forcertain applicatjons. Fishncts maclc fronr nronofilameni lravcproperties similar to those o[ the equivalent nrultinlament nets,rvith,. h orvevcr. a higher resistance lo abrasion and usually a'siiffeihand lc .

Chuitr lVarps in Corpets

The yarns, e.g. of spun colton, which are nornrally used for chainwarps ltr carpcls ntay bc rcplaced by high tenrcity polvpronvleney rn . A 120 l i la rncn t po lypropy lene yarn o f j lO aen ic i - (Cf :decr tcx ) w i th 5 tu rns / inch (197 tu rns /met re) ,S ' tw is t , fo r exrnrp le ,i s subs t i rn t ia l l y .s t rongcr t l ) i r 3 /9s c .c . (15 / j rnc t r i c j co f ton yarn .ln ndd i t ion i t has sonrc th rcc t in rcs t l rc runn i rgc ̂, i , t , C .o" , i l i , i nupon lhc pricc of lhe cotton yarn, it efiects i pricc saving oiabout 40-50 Der cent_

Carpcls nridc with polypropylenc clrain warps are similar inlppcaralrcc ancl l lcxibil i ty to carpcts nradc with cotrvcntiorlalcolton clrain warps. 1'he abrasion rcsistoncc of the pile is ictenlical

B : S Y N T I I E T I C F I O R E S

for convcntional cirrpcls lnd ' lhosc

containing polypropylcncfi lanrcnt chain warps.

. Dimensional stabil ity and luft anchoragc of lhc polypropylcnechain warp carpets are at least equal to thosc oi "oiion'"hninwarp carpets.

'l'xlled Cqrpers

Polypropylcnc l lrrl l i l i l f lnrcnt yrrns havc gained wiclc and rapidly_growing acceptance for the production of tuftccl carDcts.

B_rrlked yarns, in particular, ofTcr rnany aclvantigcs in tlr isapplication, among which thc following arc inrportant:

IItuul. ' fhe finished carpet lras a firm, lotty fccl, without harsh_ness.

Cover. The naturll bulk or covcr of polypropylcnc, with itslow spccific gravity, is grcater than rt '"t of "ny oil icr f i i :re. .fhis,coup lcd w i th a 'b looming ' ac t ion o f thc y l rn c lu r ing t i r r i sh i r rg ,p roouces a carpe t wt th n to re cover pcr kg , t l r r r r can bc o l ) ta inedwith any other fibrc.

Soil ing and Stqin l lesistance. Dirt and stlrins arc rcmovcdeasily frorn polypropylenc carpcts with warrn watcr and dctcrlcllt.

Resil ience. Thc Iarger ratio of f ibrc dinntctcr to <lcnier. thcnatural resil iencc of the fibrc, and thc largcr f ibrc lo rrca rclation-ship in cnrpcts madc from polypropylcne producc ir fabric with agood resistancc to foot tramc and furniturc marks.

lVear. Polypropylenc fibres-are tough and havc a trigh rbrasionresislance. Carpcts nradc lrom thcm havc outstanding wcrrirrgquallt ics, which arc 1>rrticularly noticcabtc on stair-nosints and iihigh-traffic areas.

G) loLU Fastness. ' l 'he colours of pignrcntcd polypropylenc

fibrcs, as uscrl i l lhc production of tuftcd carpc(s. arc flsi tndpcrnr i rncn l . a t ld w i l l ! l s t t l t c l i f c o f thc carnc i

600

- 1 r - l - - l - l l - l ' l - [ ' l

60t

II

, I

TF.F N F F. F.TH:F F F F I N N FJ}I I A N D B O O K O F ' T E X T I L E F I A R E S

Sl4fic. Carpets of polypropylcue are alntost static-Iree. Theyshorv l i l t le lendcncy 1o dclivcr shocks to pcople who havc walkedacross them, and then tcuch metal objccts. This absence of staticch:rrgc rlso coIlributcs to the soil-rcsislance of polypropylcnecarpets.

Carpet Pro(luctiottPo lypropy lcnc bu lkcd cont inuous l i lanrcn t ynrn may be uscdclncicntly (or high-speed lufting on a variety of dif lercnt typesof cquipnlent. A few sinrple adjustments and precautions are allthirI is necessary to ensurc excellent performance and a minimunro I o l l -qua l i t y carpc t .

Scwing'fhreud

I{igh strength, cxccllcnt chernical resistance, versati l i tv and lowcost havc contributed greatly to thc acceptance of polypropylcncfibrc for sewing tl lread uscd in multiwall bag and other industrialsewing applications.

Polypropylene yarns give approxinralely 65 per cent grealercoverage tltan yarns of thc same weight pcr lenglh or deuier inco t ton or rayon. Po lypropy lene o f 1 ,155 d tex (1 ,050 den) , fo rexrmple, provides the same bulk or coveraqe as a theoretical1 ,897 d tex (1 ,725 dcn) rcyon l i la rnent . eoup ied w i th thei r rherer r t l y h igher s t re r rg th o f po lypropy lcne, ih is bu lk .y ie lc la(lvantage pernlits a greater yarrlage per kg, per sinri lar t l ireadcross-sec t lon .

Laurulry Nets

Polypropylenc continuous ntult i l l lament yarrs are used withadvantage in the production of laundry nets. The following com-parisons havc been made with nylon in this application:

(a) Polypropylcne nets slrrink only half as nruch as nylon nets.(b) I 'olypropylenc nct; last twicc rs long as those nrade fronr

ny lon .(c) Attcr 150 washings, polypropylene ncls wcre sti l l in use,

having suflered l itt lc loss in strcngth. Nylon nets were of nofurther usc after 70 washings.

. (d) I>olypropylenc ncts have a bctter rcsistance lo blcaclr thannylon ncts.

602 603

Illa kcts

S Y N ' I ' I I E T I C F I I } R I J S

Comparcd witlr wool, viscosc rxyon, coiton or. lrcrylic l ibr.cs, pol1,-propylenc is thc strongcst, l ightcst and nrost cxtcnsiblc fibic o[thesc coDtntonly-usccl blankct l ibrcs. It t lso hils thc lowcst )ois-ture. .rcgain, and shows ncgligiblc shrinkagc or fclt ing durirrgwasnlng.

Polypropylcnc fibrc has provccl pnrticullr ly srritccl to thc r.rlo_duc t iou o f b lankc ts , rnd t l l c n )anr r f i rc lu rc o f b l ; rnkc ts o f t l i l l c i c r r ttypes, weighls antl sizes is irrcreasing rapidly.

Polypropylene blankcts havc low flarrrnrabil ity (conrpanrblcwith wool), and thcy arc l ight in wcight conrparcd wilh bl nkctsoI sirl i lar cover and thickncss ntade from other l ibrcs.

Because of the high strength and cxtcnsibil i ty of polypropylcnc,more sevcre raisiug treatmcnls nray bc r,rscd than arc possibic withwool or othcr weaker fibrcs. This also rcsults in bulkicr, rvarntcrblankets, as lofticr naps can bc procluccd wilh dctcriortl ion jnblankct strcngth or incrcasc in fibrc slrcdrling during usc.

. Polypropylene blankcls nray bc hLrndcrcd quickly rnrl cl lcct-t i vc ly , bu t thcy shou ld no t bc i ronc< l o r l ro t p rcssc t l , ' l ' hcy s l ro r r not be dry-cleancd, as this hils a dclctcrious cllcct on tlrc hlntl lc.

Cqrlrets, MoErettes a d Rxgs trcm Staplc l;ibrc

Polypropylcne staplc fibrc is now bcing widcly rrscd in thc pro-duction of carpcts, Inoqucttcs and rugs, in which lrpplicrtions itoflers a combinatiou o[ propcrtics lhat cnablc it lo cor)1)clc cllcc-tivcly with othcr f ibrcs.

Potypropylene fibre is l ight and strong, and has I vcry goodresistance to abrasion. It does not fclt, cvcn aftcr prolongcrl ic;tr.It,does not soil or slain, and is of very low flamrnabil ity. 't h" typ",of polypropylene fibre used in carpct production arc cornnronlyp igmentcd , a r rd the co lours a re very Ihs t to l ia l r t an t l ru l )b i r r r .

Manufaclurcrs produce gmdcs ol polypropyicnc l ibrc whijare specially designc<l for usc in carpcts, with nro<lcralc tcnsilcI tJcngth about 2 ( r .5 cN/ tcx (3 g , / ( l c r r ) r ld h igh c long l r t io r r (a l r r r t r t80 /o) . F ib rcs o f th is typc l tnvc excc l i c r r t c las t i c p ro i rc , r t i cs rvh ic l rrender them particularly suitctl to usc in carpcts.-' rcy h:tvc irhigh rcsil ience oI the sanre ordcr as rvool.

Polypropylene carpcts, rugs and nloqUcltcs havc cxccllcntdimensional stabil ity, are easily cleaned and driccl, do not pick up

I IANDt rOOK OI ' f EX 'T I LE r : I t rRES

t l i r t readi ly , and rcs is t s ta in ing. 1 'hc co lour fastncss of p ignrcrr tcdfibrc is good, and abrasion rcsis(ancc is hidr.

Carpcts and rugs are light in weight, dJ not fclt with washineor wear, and are conj[iletely resislant to insecls ancl micro]organisnls. Thc fibres nrclt when subjectctl to heal, for exanrole.Ironr a cigarctte stub, and can bc regarde<I ns sclf-extinguishirrg.lr.larks lelt on a carpet are no larger thatr the stub whilh rnaalI ncnl.

PolypropyJcnc js allccted by Iight to a degrce conrprrablc withpolya|rltde ttbrcs.

U pholstery

Thc production of uplrolsrery fabrics lrom polypropylcnc stapletrbrc ts an application of rlpidly_growing irrrportancc. In tir isficld, the properries of polypropylene libie olier -onu uduoii_llgcs ovcr conrpctit ive fibrcs. Thc low spccil ic gravity;csults inIightncss and cxccllent covcrirrg power. Higlr abiasion rcsistancc.reslslancc to lcl l ing, sti l in rcsistancc, low 0anrrnabil ity, negligiblcwalcr-absorption, icsistancc lo nricro-orgaDisnl, on,l ' in."it i otithese. are useful ch racteristics in a fibre that is to be usccl'Iorupholstery fabrics. The pigmented polypropyleiie nfri.r-r* "ir""fast to.light, to rubbing aud to washing.

Upholstcry fabrics are commonly made from 100 per centpolyplopylcnc fibrc,. arrd nrany n)anulnclurers producc st:rptc Drc wnlc l l rs sur t rb le lor th is purpose. Fabr ics are gerrera l lybackcd with latex conrpounds.

Upholstery fabrics madc from polypropylene are easily cleanedusins

,lukcwarnr water and synitreiii <teiergent.. D,t'"i;;;;;;should be avoidcd.

ln.conrnron with oUrcr typcs of polypr.opylcne labric, they showexcellent stability to rvear. lhc high abrasion resistance is ani rnpor tant c l laracter is t ic in t l l is apt l icat ion, as are polypropy-lene's resistrrrce to nricro-organisrls and iirsects, uu,t ik t'o'*f lanrnrabi l i tv

K iuvear

Po lypropy lc r rc f ib lc i s n rak ing s tcxdy progrcss in thc ku i twc t r| l c ru . t r o c rs n t i rny a t ( r l c t i vc p roper t ies in t l : i s app l i ca t ion , in_c l r r ( l t g i r t t excc l l c t t t l l and , lo f t , d imens iona l s tab i l i t y , co lour fas t_ness, casy care, atrd all-rorrnd wearing qualit ies.

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l ] : s Y N - n l l j I I C r l A R e S

P-olypropylcnc yarns itrc ir lso slrong, tough nnd highly fcsist:urtlo f l cx ing r rb ras ion and chcnr ic i r l a t t rck .

' l hc low sgrcc i i i c g r r rv i ty

and high coverirrg powcr arc irlso ;ldvar)l irgcous iri ttr" kri itrv"r, 'rl icld.

, nll thc stirndirrd.tcxturing plocc$scs ltay bc trscd on polypropy-

leDc yarns , Inc iudrng l l sc tw is l ing , s t l t l l c r box c r i r r rP i r rg , cdgccrinrpiug aud other systems.

Polypropylcne yarns lravc lorv shrinkagc iu l lot witlcr, goo(lrcsil iency, and high wrinklc-rcsislancc.

lllcnds vith Rt)'on

1 'he b leud ing o f .po lypropy lcne w i th cc l lu los ic I ib rcs , such.asr lyon , . i s an . cxcc l l c r r I way o f con t ro l l ing s l r r inkagc car rscc l bvlctaxatton crinlping. -l-cDsilc

strcngth a d abfirsion |.csisturrcc arcalso im.provcd by incorporalion of thc polypropylcnc fibrc.

Fabr ic shr inkagc nray bc . rc t l r rccd by a i -n ruc l r f l s 60 to ?0per ccnt in this way at vcry low cost.

Paper' fbc

add i t ion o t lo lypropy lcnc s tap lc { ib rc to wood pu lp Uscd iDpapcr-making aflects thc physical propcrtics ot laicx_.satrrratcripapcr tn .a nurnber o I ways . In par t i cu l t r , i t b r ings about amarked incrcasc in lci l l . strcngth, trolypropylcnc-sirclgtlrcn"Jprpcrs o[ this lypc rre valuablc for nranyipciiality appli i l t ions.

Cortyeyor Dclting

Polypropylene nrulti0lament yarn cornbincs nrany of thc tlcsirablcpropcrtics. of_ a convcyor bclting yarn, i lclurl irrg ir igh .rr",,eti, iu,low cosl, t gtl I|todulus, high cxtension nt l.rrcak lrrrd high work ofruplurc. Also, polypropj,lcnc yarn is corrrplctcly inscnsitivc tomorstule.

. fhere are two.main problcrns in lhc usc of polypropylcnc yarrr

1S, . , . ^on l " ro r .bc t r i r rg . F i rs t l y , i r i s d i l t i cu l r to bor r i t l i r ' r .ubbc i o rr .v .u . sccond ly , j t n rc l ts a t boUt . 165.C. l r r r r l s l t r inks bc low t l r i s(cnrpcra ture i f hc ld in an unrcs l rn incd co t ld i ( ion .'Ihc

problcnt oI adlrcsion has tcndcd to rcstrict t lrc usc o[ nolv-propylerc fibrc in bclting applicatiols to trlcrr<l f lbrics rvjihcc l lu los ic s tap lc f ib rc . l l l c r rds w i th co t ton : rn ( l . l ) r r r l r l i l , p rov i t l creinforccrncnl fabrics whiclr arc compctit ivc wirtr olttcr typ"s oibclting fabric on a strcngth/cost basis.

-liIIr l r a

l l

FFf_F F FroF F F FJJJJJJI I A N D B O O K O F T E X T I L E F I B R E S

ApparcL Fabrics

i

Ltulics'I!osietyPigrnented continuous fi larnent pclypropylcne yarns proviclecom[ortable, soag-resistant stockings.

Ktrit I'ilc l1abric Bucking Yarns

The strength and Iight weight of polypropylcnc staplc fibre servcit well in this applicatioD.

Men's Stockings

Exccllcut stockings are nladc frortr blcnds of polypropylcne staplcwith acrylic l ibre.

Drcss l(tritvear

ll lended rvith rayon, polypropylcnc staplc l ibrc pr.ovidcs knitwcarof excellent hand. Blcnded with wool, it is uscd for swcaters andolhcr garmcnls o[ this type.

Continuous l l lanrenl. texturcd yarns arc also usc<|.

Ccllulosic BIetds

Il lcnds of polypropylcnc staplc l ibrc with cotton and othcr ccllu-losic fibrcs show great promise as apparel fabrics. Blends withcotton conlaining up to 20 pcr cent polypropylene may be ironedwithout dif l iculty. The dcvelopmcnt of low-tcmpcftrlurc curingrcsins has incrcascd thc vcrsati l i ty and scopc of blcndcd ,naterialsoI t lr is sort.

t ' t Iu ou()

I ,dDftcs

Staple fibrc and contiuuous nlult if i lantcnt yanls rc wovcn intofabrics that have exccllent chentical rcsistancc, high strength andlong l i [ c .

I'yre Cord-lyrc

cords arc nradc fronl slaplc, multif i lantcnt and rrronoli lanrentyarns. Polypropylenc can be madc in vcry high strengths for thisapplication, but the low melting poirlt placcs sonre restrictionon usc.

606 607

l ] : sYN I E l lC I r l l l l r t s

A'I isce I I uttc o ru U v' "^

I'ibcrfil

Polypropylcnc fibcrfi l is uscd in slccping bags, rnil l lrcsscs lndquiltcd fabrics. It is l ighl, washcs easily and is con)plctcly rcsis-lant to insects and micro-organisms.

Car Upholslery

Polypropyleue monofil irrncnt yarns providc upholstcry l lbricswith long l ifc, soil resistance and low static charactcristics.

KDit Pilc Boor Li itgrI ' igntentcd polypropylcne staplc is usc(l for this applicatbrr, pro-viding cxcellent thermal propcrtics, inrprovcd pilc rclcrrtion andrcsistaucc to insects, rnildcw, ctc.

POLYPITOPYLENE SPLff FILM III I}I{I]S(FtBRILLAI ' INC l r rLM)

lN f I{oDUCl tON

It has long bcen knorvn that f ibrous mn(cril ls could bc produccdby splitt iog synthclic polymcr l i lurs. A pirtcnt coverirg lhis tcch-nique was fi led duliug thc 1930s, but l i tt le practicirl usc of thcprocess has bccn nadc rnli l conrparativcly rcccnt t inrcs.

' l 'hc

conrnrcrcial dcvcloplren'r. of polyolcfins has stirrrulttcd rcncwcdi[tcrcst in tlrc produclion o[ split t i lnr l ibres.

Many polyolefin manufacturcrs are now prorlucing split l ' i l lnl ibres, notably from polypropylcnc, which oflcrs thc optinrunrprice / properties coinbination for thc typc o[ uscs forcsecn Iorthcse l ibres. Polypropylcne split l i lm 0brcs rnay bc as nruch as25 per cent cheapcr to produce than thc corrcspontJing ntult i l i la-ment yarn, and for this rcasorr t lrcy arc making mpid hcadwayilr Drarkets that wcrc prcviously closcd to polypropylcnc tibrcs.

Outlcts for polypropylene split f i lm fibrc includc nrooriugropcs, f ishnct twinc, ropcs and cords, packaging twincs, f ishingnets, balcr twinc, hosc rcinlorccntcnt and clcctricl l cords. Spccialtypes of polypropylcnc split f i lm fibrc suitablc for wctving hirvcbccn developcd; thcy arc uscd, for cxanrple, in thc protluclion ofcarpct backings nnd packiug flbrics.

T I A N D B O O K O F T E X T I L D F I B R E S

PI {ODUC' | ION AND PROCESSINC

lvlany mcthods havc bccn invcstigated for thc conversion of syn-thctic polymer fi lms into fibrous matcrial. These include scribing,cutting, abrading, air blowing and othcr tcchniques ainred atsplitt ing the l i lm along weak spots which would develop intocracKs.

Init ially, thc production of f ibrc fronr fi lrn rvas regardcd as arcsponsibil i ty o( thc manufacturcr, but this attitude has norvchanged with thc development of l ibri l lating l i lm which is con-ycrtcd to l ibrous yarn by spinning undcr standard conditions oftcnsion, spccd and twist lcvcl. The manufacturcr supplics fibri l lat-ing tapc or f i lnr, wlriclr is uscd as raw matcrial by the spinncr.

This tcchni<1ue of using fibri l lating fi lm avoids tbe completebrcakdorvn of the fi lrn into l ibri ls, which was a feature of manvcarly lcchniqucs. Thcre is no sacrif icc o[ lhe advantages of co-hcsion, knot slabil ity and strcngth which products based onpartly-fibri l latcd yarns possess.

STITUCTURE AND PITOPERTIES

Thc propertics of yarns made fronr split f i lnr arc basically similarto those of conventional polypropylcnc nultif i lament yarns. Thesplit f i ln yarns tend to have a firmer handle, however, than theconventional type of yarn.

POLYPROPYLENE SPLIT FILM FIBRE IN USE

'fhe inil ial dcvelopnrcnt of polypropylcnc split f i lnr has been in

lhe l lelds of coarscr industri ir l products, rather than in the fi lcrindustrial or apparel yarns. Use of the fi lm o[Iers great ccononriesin raw malcrial and ptocessing; several stages of processing areclinrinated by using a fibri l lating tapc in placc of convcotionalfibres, for cxanrplc, in the production of twiDcs and ropcs.

Thc use of split l i lrn has made fastcst progrcss in thc highly-compctit ive markets whcre chcap, strong rotproof n')atcrials arcrequircd, e.g. ropcs and trawl t lvincs, packaging twine and balertwrne.

I

608 609

r l r--l

B : S Y N ' I ' I I D - T I C F I T } R E S

I'uckagiug T vinc

Singlc-trvist trvincs ur;rclc fronr polypropylcnc split l i lnr hilvc thclrropcrlics desirable in packaging twincs, c.g. of thc lrcavicr typcuscd in tying buntllcs oI [cwspapcrs, parccls, lc(crs, clc.

' l lrcy lrc

also kind to tbe hands and arc trouble-Ircc whcn uscd in iuto-nratic tying machines.

Ilopcs

Polypropylcnc sPli l. l i l | lr ropcs contpilrc lavourably ir) strcn8thwith otlrer syntlrctics of conrparlblc pricc, show cxtrcrtrcly lorvcrccp, and lravc an cxccllcrrt rcsislancc to kinking or hockling.l]ccausc o[ thcir high rcsistancc [o conrprcssion, thcsc rol)cs donot rcndily mclt rvhcn running ovcr wiuch barrels, fair-lcatls,pulley-blocks or otlrcr bcaring surfaccs.

lJeciiuse of lhcir high strctch resistancc, low conrprcssibil i ty lndlorv cncrgy absorption, polypropylcuc split [ i lrn ropcs arc s:rfcr tohandlc lhau sonrc othcr typcs o[ rol)c, nncl t lrcy do not tcnd locxhibit 'whiplash' whcn suddcnly rclcascd frorrr slrrin. ' lhcy

lrccspccially suitable for npplications wlrcrc a nraxirrruln rcsisllnccto strctch is rcquircd, ratlrcr than for ortt lcls rvhcrc I rrr;rxirrtun]cDcrgy absorption is nccdcd.

-fhis nrakcs thcnl suiloblc ptrticu-

Iarly for eld+rses such as fishnct rnounting ropcs, lnooring anclhauling ropes, ancl cargo slings.

Baler Twirte'l-his

is onc of thc lalgcst polcnlit l nrarkcts for polypropylcncspli l f i lm. Attempts to rcphcc lhc conlltonly-uscd sisal with olhcrtypcs o[ f ibrc havc gcncrally failed ou ccononric grounds, and onpoor knot slabil ity. I lalcr lwil lc rnadc fronr polypropylcnc splitf i lm fibre has good knot stabil i ly, lorv wcight, good rcgularity, rrrdhigh strcngth.

l'ishnct 'l'vines

l:or ccrlain typcs of lrottorn Iri lwl i l tr(l I)anish scinc nct. it issonrctirncs dcsirablc to l lavc fl twjnc with u grcatcr sti l lncss thilnthat obtainablc with polypropylcrrc nrultif i lanrcnt yarns. ' l 'wincs

based on polypropylcne split f i lnr htvc thc rcquircd sti lfncss. \.vitha highcr straight and knot strcngth tlran polycthylcnc twilcs conr-nronly uscd, a highcr rcsistance to slrclch lnd crccp, and aknottnbil ity compnrnblc vith lhat of thc natur l f ibrc trvincs.

'F.FF.[F-FJJ,F. F.r - i l -t t i

I H A N D a o o K o F T I I X I I L E F l l l l { u s

5. I'OLYUltli'l'lrAND FII'RES

Fibres spun fronr polyntcrs ntade by a reaction taking place be-trveen small noleculcs, in which thc l inkage of the moleculesoccurs through the folmation of urelhane groups ( - NIICOO - ).

Linear polyurethanes may bc nrade by reaciion of a glycol witha di-isocyanatc. The reaction of butanc diol, for exanrple, withtolucnc di-isocyanatc results in the formatiotl of a polyurethanein lhc following way :

cHr

<\locN\.! Nco

. T O L U E N E D I I S O C Y A N A T E

IYC H :

--- o(cH,).o.coNt, Q "".o.o 1.n';"o

BO (CHTJ4OH

E U T A N E D I O L

POLYURETHANE

INTI{ODUCTION

lvlore than a century ago, it was discovcred that a reaction tookplace betwecn the isocyanate group, -N=C=O, and the hy-droxyl group, -OH, resulting in the formation of a urethanegroup, -NHCOO-. During tlle rcaction, thc hydrogen atom oIthe hydroxyl group urigrates to the nitrogen atom of the isocyan-ate: the residue of the alcohol is transferred to the carbon atomof the isocyanate group:

n-NCO +R'-OI I -+ R- NI ICOOI{ '

During the late 1930s, this reaction was used for making poly-nrcrs, by using il. to link togcther two types of snall molecule, oneof which contains two jsocyanatc groups (i.c. a di-isocyirrrate) andthc othcr trvo hydroxyl gloqrs (i.c. a glycol). ' l he polynrerizrtionwhich occurs in this way does not iuvolve the loss of water or

6 1 0 6 l i

I'.FJJJJJ

B : S Y N ' I ' T I E T I C F I B N D S

othcr small ntolccules, and it is thercforc an additiorr rrthcrthan a condcnsation polyrncrization.

'Pcrlon' U

During World War II, a fibrc was spun in Gcrnrany front a poly-urcthanc fornred by thc rcaction of I ,4-l:tt tn ncd iol with hcxa-nrethylene di-isocyanate :

HO(CH").,OH r- ocN(cFI!),,NCO->[- o(cH,).ocoN r-r(cLr,),,Nr.rco - ],,

This first polyurcthanc fibrc was markctcd as ' l 'crlon' U. ltborc a gcneral lesenrblarrcc in nrany rcspccls to nylon, bttt i t wusinfcrior to nylon as a tcxti lc l ibre. It nrcltcd at 180'C., Iorcxamplc, which is lorvcr than is dcsirablc in lrn Dpurcl f ibrc. ltwas stif l , with a harsh wiry handlc; i l had a nroisturc rbsorptionlower than nylon.

'Perlon' U achieved some linrited succcss during World War Il,l inding markets in rather specialized applicatioDs such as brushbristles, nltration fabrics and othcr industrial uscs. lt did notcompcte e{Iectively tl i lh the rapidly developing nylon, howcvcr,and polyurethane fibrcs of this typc haye madc litt lc hcurhvuysince the war.

Elastomcric Fibres

ln recent years, polyurethrncs have nchicved a ncw and incrcns-ing importance jn lhc texti lc rvorlcl. Thcy havc bccontc lhc brsiso[ a novcl type of clastomcric fibrc which is knorvn gcnct.icirl lyls .r2arrrlc.r (sec dcfinition bclorv).

Elastonrcric f ibrcs irrc thosc which display clasticity chilractcr-is{icri irssocintcd rvit lr natural rutrbcri thcy wil l slrclch lo scvcrtlt i r r rcs thc i r o r ig in r l l cng th , and on rc lc lsc rv i l l s r rap l )xck qu ick lyto rccovcr thcir originul lcngth alntost complctcly.

Natrrral rubbcr fi lanrcnts hlvc long bccn lrscd in lhc lcxli lcinduslry lo providc strclclr propcrlies in fabrics and gnrnlcn(s.Rr rbbcr f i lanrcn ts w i l l ' g ivc ' undcr thc ac t ion o f r fo rcc , anc l lhcslretchcd fi lanrcnts wil l thcn cxcrt r rccovcry forcc rs lhcy try torcturn lo thcir originrl shapc. 'Powcr slrctch' frbrics uscd in

} T A N D B O O K O F T E X T I L E F I B R E S

clastic rvebbings, support and foundation gitrntcnts, [or cxamplc,derive their propcrtics frorn fi lanrents oI rubbcr or sitnilar matcr-ials incorporated in thc fabric.

Natural rubber fi lamenls have been supplying thc power tostrctch fabrics for morc than a hundred ycars, and thcy haveestablished a position o[ some importance in the texti le industry.Unfortunately, natural rubbcr has seyeral shortcomings with res-pcct to its r.rse as a texti le matcrial (see page 153), and fibrcchcmists havc long bccn sccking to dcvclop clastorncric nraterialswhich would be superior to rubber in recovery force, resistanceto abrasion, chcnrical stabil ity, dyeabil ity and olher properties.

Thc elasticity of natural rubber derives from its long, fol<ledpolymcr molecules, which are l inked together at intervals by tbcchcntical bonds introduccd during vulcanization. Whcn a fi lamentof vulcrnized rubber is pullcd, the loug rnolccules unfold and thcrubber stretchcs. Thc extent of lhe defornation is rcstricted bvtl le l inks bctwccn tlrc rnolcculcs, and whcn ll lc tcnsiotr is relelscithc long molecules tend to rcvcrt to their relaxccl, folded statc.So the fi lament springs back to its original form.

Elastic f ibrcs produced from natural rubbcr bavc exccllentclasticity, bul lhe tensilc streugth and force of recovcry fromstrctch arc lcss thnn adequate for the production of l ightweightgarmcnts. Iu addition, the double bonds which remain in therubber molecLrles after vulcanization impart chemical reactivitv.espccially with rcspect to oxidising agents. Finally, tt" hyAro-carbon nature of the rubber nrolecule results in a low acceoiauceof dycs .

In tl lc search for ncw typcs of claslotneric f ibre, chcnrists havesought. to dcvelop nrolecular structures which would provide thcfundanren la l rcqu i rcnren ts o f rubbcr - l i ke e las t i c i t y , bu t d id norhave the disadvantages inhercnt in the hydrocarbon structure ofrubbcr itself.

lilns(ic PolJanridcs

ln rubbcr, thc tic-points holding thc long nrolccules togcthcr atintcrvals cotisist of covalent chemical bonds introduced durinpvulcanization. lt was realizcd, howcver, that l incar polymcr nrolelculcs could be l inked cffcctively by tie-points resulting fromhydrogen bonding devcloped by polar groups in the molecules.If a polymer rnolecule could be ntadc, for exanrple, in which longsegmcnts of 'amorphons-type' moleculc were l iuked together by

6t2

-L--l--ft--- U f Li L_i L_' L '' n [ , , [ ' L ' L , t u L , ' u L , t

B : S Y N T I I D T I C F I N R E S

polar groups, lhc rcquircnrcnts o[ rubbcrJikc chsticily nlight bcmet.'fhc polar groups would cstnblish strong forccs bctwccn thcntolccules, providing tic-points scparatccl by scgmcnls on non_po lar n ta tc r ia l .

A grcat dcal o[ rcscarch was cirrricd out in tttcn]pts to nlakcelastomeric fibres from polyamidcs in lhis way. polyanitJcs wcrcnradc by condensing dicnrboxylic acids with I nri iturc of twodiamines, onc of which had substitutcd (sccontllrry) tnrinc grorrps.1'hc polynrcr fronl this condcosltion includcd tr;o "lcnr",i i , ui"_essary for thc cstablishmcnt o[ high clasticity; (t) a pliablccons t i luen t o f low mc l t i r rg po in t w i th poor in tc rc l ta in bond i r lIorcc. (thc N-substitutcd polyamidc scgmcnt, and (2) an intcrclrairrbond ing cons t i tuent ( thc unsubs t i tu tcd po lyarn idc w i th i t s hydro-gen bonding capabil ity).

. Elastic p_olyanridcs of this typc wcrc madc, for cxamplc, fronrhexflntcthylcnc diarninc and scbacic acid (i.c. nylon 6.lt i typc) inrvhich a proportion of thc hcxnnrcthylcnc rJianiinc *n. ,.ri ln.",jby.a dianrilc carrying bLtlky butyl groups. . l.hosc

rcgions Lf t lrcnolcculcs formcd frorn lhc hcxnntethylcnc dianrinc

-and sctracic

acid wcrc ablc to align thcrrrsclvcs cioscly, and dcvclon stronchydrogcn bonds bctwccn thc molcculcs: thoic rcgions of t ir" nroi"jculcs fornrcd from the substituted diaminc, on thc othcr hand,wcre unable to align thelnsclves, forming rcgions o[ anrorphouipo lyamidc .

When thesc fibres wcre strctched, thc rnolcculcs in lhc flmor-phous rcgions wcre ablc lo unfold, thc dcgrcc of strctchinl ofthc l ibres as a wholc bcing rcstrictcd by the powcrful borrdirr-n oithc lnolectrlcs in lhc cryst:rl l inc rcgions. Wlrcn thc lcnsion

-wls

rclcasc<l, the molcculcs in the amorphous rcgions tcnclcd to rcvcrtto thcir original positions as the fibre rccovcrcd fronr its strctch.

Segmculcd Polyure(ltares

In the random copolymers produccd from nrixcd cliamincs, thcaverage lcngth of the two conslitucnts was rathcr small, Thcscqucnccs of N-substitUlcd polyanridc urrits wcrc loo short topcrnrit of thc dcveloprncnt of thc chain ncxibil i ty ncccssary forhigh rubbcr clastic forcc, whilc l. lrc scqucnccs of unsubsti iutcdpolyanride units wcre too short to prevcnt. rupturc during strctch_jng-or hca t i lg ( rup turc d r r r ing s t rc tch ing causcs f low i ru l> lu rcduring hcating rcsults in lorv softcning point). Whrt was ncc,l"Jwas a polymcr molecule in which lougcr scgntcnls of nmorphous-

6t3


type structure were separated by segments of nlolecule capableof developing powerful hydrogen bonds.

The solution to these problems was found in the developmento{ polyurethane polymers in which segments of the molecule aredeliberately tailorcd to perform the desired functions. The lackof f lexibil i ty of the pliable conslituent (with low melting point)was overcom€ by using preformed segments of molecule of con-siderable size (the 'soft 'scgments); the cohcsion of the interchainbonding constituents ('hard segnrents') was assured through theuse of urethane or urea groups.

The devclopment of these scgmentcd polyurethane polymcrshas providcd the texti le trade \vith an entirely new type ofclastomcric l ibrc-the spandex fibrc. Dcrived lrom n polynrerthat dil lcrs [undarnentally from tl]e hydrocarbon polymer ofnatural rubber, the spandcx fibre is stronger tltan rubbcr, ancl hasa greater 'recovery power'. lt is a white or clear and near-t ransparent f ib re , capab le o f be ing dyed to match o thcr f ib res in afabric. Globek 'Sheerspan' produces sheer-looking labrics inrvhite, and its high degree of dye receptivity results in a fabricrv i lh sharp , deep and d is t inc t shades.

Spandex fibres have a high resistance to chenticals, sunliglttand other degradative influettces, aucl ntay be rvashed repeatedlyrv ithou t i l l-effect.

The first spandex libre, du Pont's 'Lycra', was introduced onto the market in 1958, and commercial production began in I960-6 t .

Since then, many firms have followcd suit, and tlrcre are anunrber of spanclex l ibres now available.

1"I'PES OF POLYURETIIANE I:II]RE

Thc process used iu producing segnreutcd polyurethane Iibres(see 'Protluction' bclow) is such as to allow of almost infinitevarii l t iorr in thc chcnrical structurc of thc polynter thut is fornrcd,

Modcrn segnrcutcd polyurcthanc fibrcs nray be corrsidcrcd asfall ing into one or othcr of two gencral typcs rvhich difTer in thechemical structr.lre of the 'preformcct' segmcnts of the molcculc.In this respcct, scgnrented polyurethane fibrcs arc cither

(a) polyether types, or(b) polycster types.

614 6 1 5

B : S Y N T I I E T I C F I A R E S

IJolh types of scgmcnted polyurethanc fibrc are produccd byfibre manufacturcrs in considerable variety, providing a rlngcof elastomeric fibres which neet many diffcrcnt cnd-trsc rcquirc-ments.

The polymers formed by l inking preforrned scgmcnts o[ poly-cther or polyester molecules, via the urethans group, nray bccssentially l inear molcculcs, or they may bc branchcd an<l/orcross-linked into three dimcnsional structurcs.

'fhc l incar typcs

arc generally capable of mclting, and wil l dissolve in nppropriir lcsolvcnts. Thc thrce-dimcnsional typcs may bc cornplctely insolublcand non-melting.

Fibrcs spun from tl]ese scinrcnted polyurcthtncs may bc inthe form of monoli lan]ents, or they may bc mullif i lament yarnsin wlrich a number o[ 0ne fi lamcnts have coalcsced after spinning.Monofilanrents may also be produced by cxtruding shccts of thcpolyurclhane and then cutting this into l i lamcnts.

NOMENCLATURE

Elustoncric Fibra

Thc segmcnted polyurethanc l lbrcs now on lhc markct arc rl lcharacterized by thc high cxte0sion and snap-l>ack rccovcryassociated with rubber-l ike clasticity. Thcy are thcrcfore propcrlydescribcd as elastomeric l ibrcs in that they rre fibrcs which bchavcin a rubberJike way.

Tlre tcrm elastotneric fibre <1ocs not, of coursc, rclrtc to thcchcmical structure of a fibre, and it should bc realizcd thflt i t isnot synonymot|s wilh 'scgmcntcd polyurethane' or 'sprndcx', l]othof t lresc lnttcr tcrnls arc basctl upon thc chcmical sttuctrrrc ofthc l ibrc (see below).

Federal Tradc Contnission D?littiliotl

1-lrc gcncric nanlc spandc.r wls adoptcd by thc U.S. l:cdcr:rl ' l 'rrt lcComnrission for f ibrcs oI the scgmcntcd polyurcthlnc lypc, thcoll icial defiuit ion bcing as follows:

Sparulex. A manufacturcd fibre in which the fibrc-forrl ingsubstance is a long-chain synlhctic polymcr conrposc<l o[ at lcnst85 per ccnt of a segmentcd polyurclhane.

T I A N D U O O K O F T E X T I L I ] F I D R E S

PRODUCTION

Spandcx fibres are spun from segmented polyurethanes rlade bya serics of chcnlical stagcs, as follows:

(l) Producl.ion of low molecular wcight polymer (pre-polymer)

(2) Rcaction of prc-polymer with di-isocyanate(3) Coupling of isocyanatc-tcrnrinltcd prc-polymcr to

form segmcntcd polyurethanc.

(l) I 'roduction of Lory Molccular Wcight Polyncr (Prc-polynrer)

The lirst stcp in the synthcsis oI a spandex fibre is to crcate tl 'rcsofl segment of the molcculc, i.e. that segment that providesthc amorphous region in which the unfolding of the nroleculcspermits extension of the fibre to takc place.

'I-wo clirsscs of compounds, polycstcrs and polyethcrs, are conr-

nronly used for this rubbery solt scgment, the naterials produccdbcing polymcrs o[ lorv molccular wcight (500 to 4,000) wirhreactivc hydroxyl groups at each cnd o[ thc ntolccule.

'fhcy arc

mactoglycols, which are nradc by normal polymerization tcch-r ques.

Polyeslers are madc by condensation of dicarboxylic acids witha slight excess of glycol; thc condensation takes place unti l thereare glycol units at each end of the polynrer molccule, which thushas hydroxyl cnd groups (A).

Polyctlrcrs are nrade by the ring-opening polynrerization ofepoxides or cyclic cthcrs (B).

( A ) H o o c - R - c o o H + t l o - R ' - o t l +

r r o l n ' o o c - R - c o o I R ' o HL - J N

Pf tE - POLYL, lEn (POLYESTEn)

{s ) P-c l i?o { r i ,o . -> r ro (n - o . r .o )n- n - c r . r ,o r rl � I

PnF- - PoLYMER (Pol-YFr l lER)

Product ion of Prc l )o l ! tDcr

t t\

6 1 6

- - l r ! , [ n I n I

6t7

I } : S Y N T I I E ' T I C F I B R E S

. I 'hc slrl, j turc o[ thc soft scgmcnt influcnccs thc propcrlics oflhc rcsu l lan t po lynrc r , c .g . me l t ing po in t , ncx ib i l i t y ind chcnr ica lslabil ity, aud thc selcction o[ the type of soft scgnrcnt to bc usctldcpends upon the typc o f f ib rc rcqr r i rcd , anc l o r r rv r i l rb i l i t v andcost oI rlw rrratcrials.

(2) llcaction of ltr.c-polt'llrcr rvith l)i-isocyrnlrtc' l ' l lc

ncxt stcp in thc prodtrclion of t l)c scgnlcntc(l polyrrrclhanc isto convcrt thc so[t scgn]cnt rnacroglycol into a prclrolynrcr whichhns isocyanatc cnd groups, Thc nracroglycol is rcrctcd with ancxcess o( di-isocyanatc. thc hydroxyl groups otr lhc cn(ls of ttrcnracroglycol molcculcs rcacting witlr isocyflnltc groups to forrnurcthanc groups. lI two nrolcs of di-isocylnatc rrre usc<l pcr molcof nracroglycol, lor cxarnplc, a prc-polynrcr is forrnccl in whichcach molccr.rlc now lurs isocyanatc crtd-groups.

H O - P o t - O H + 2 O C N - R - l \ t C O - >

PRE.POLYMER

o C N - R - N H C O O - P o t - O C O N H - R - t . t C O

l iocvnDr lc t rct lntcnl o l prc-polyntcr .

' fhc rcactivity o[ thc di-isocyauate dcpctrds ut)on i ls structurc.

In gencral, thc aronralic di-isocyflnatcs arc nrol.c rcactivc thilnthe non-aromatic. Aronurlic (l i- isocyanttcs arc also conrnrcrciallyavailablc, aod thcy arc uscd prcdon)inantly in thc rcrction uscrl i irbuilding spaudex polynrcrs.

(3) Coupling of Isocyaltlc-lcnlinltcd prc-polynrcr to forrl Scg.nrcnlcd Ir0lyurcth:roc

'[ 'hc l inal stcp in rruking lhc scgmcnlcd polyrrrctlr lnc consisls in

lhc crcation of lhc hard scgntcnt by .chain cxlcnsion', or couplirrgof thc isocyanate-tcrminfltcd prc-polynrcr by rclction with lo;nrolccular weight bifunclioral conrpouncts, sLrch as glycol ordianrine. Thc .rcaction product is a polynrcr having hy<trogcnbonding sitcs in tlrc form of urclhanc or urcn groups, nt tJrsttwo o[ uhich wil l occur in thc rcsulting .hard scgrncit '-

t

n fi F-FFT.FJJI fi r'i- t: 11HANDBOOK OF TEXTILE F IBRES

(1) 9!199!O C N - P o r - N C O + H O - R - O H - - >

- ocoNH - Pot - NHcooRoCoNH - Po1- NHCoo -

(2) DIAMINE

ocN - Pol - Nco + H2N - R|-NH, --->

_ NHCONH - POT _ NHCONH - RI - NHCONH - POt - NHCONH _

Chain extension with glycol or diamine.

This final chain extension stage may be carried out also byaddition of water to the isocyanate-terminated prepolymer, insteadof a glycol or a diamine. Water may be added, for example, inquantity sumcient to react with a proportion of the terminalisocyanate groups, forming pre-polymer molecules with anisocyanate group on one end and an amine group on the otherend (l). When this polymer is heated, the amine and the isocyanategroups react to bring about firrther polymerization and cross-linking of the molecules (2).

ocN - Pot - Nco + Hro $ocN - Pot - NHrn co,

oct.r-Pol-NH, t oCN - Por - NH, g!

ocN - Pol - NHcoNH - Po1-NHz

Chain extension with \rater

This reaction results in only one urea group for each twoisocyanate groups, carbon dioxide being liberated as a by-product.The evolution of gas during chain extension may be regarded asdesirable in ihe production of polyurethane foams, but it is usuallyto be avoided in the production of polyurethane fibres.

Spandex polymers produced in this way may be essentiallylinear molecules, in which end-to-end linking of bifunctionalmolecules is the predominant reaction. Such materials are com-monly soluble in appropriate solvents.

If branching occurs during the polymerization process, however,e.g. by reaction of the isocyanate end-group with an activehydrogen in the molecular chain, the polymer may build up intoa branched or cross-linked three-dimensional structure. Suchpolymers may reach the stage of being insoluble in any solvent,and incapable of melting.

6 1 8 6t9

'-Ellt: sYNt l tEI lc FIBnES

Spinniug

The technique used in spinning spandcx fibres depends upon thctype of polymer that is spun. Some segmented polyurethancs, forexample, are essentially linear molecules, and are solublc insolvents. Other segnrented polyurethancs may be branchc<.I orcrossJinked structures which are insoluble.

(a) Lirrcar (Soluble) Poly uret hunesSoluble polyurethanes are dissolvcd jrr an appropriale solvcnt,and the solutions may be extruded through spirincrcts into acoagulating bath (wet spinning) or into an atmosphere whichremoves the solvent (dry spinning). The techniqrrcs aic csscntiallvthe same as those used for sp inning,hard 'synthet ic f ibrcs, dueallowance being made for the fact that spandex fibres arc elastic.

(b) Bronchetl or Cross-linkcd (lnsoluhlc) polyurdhunrs

When the nrolccule of polyurethane is allowcd to grow into athree-dirnensional structure, it is insoluble and cannot bc spunby the above techniques. ln tbis casc, a ,chemical spinning'pro""s,may be used. The isocyanate-terminated pre-polymcr ii spun ata stage when it forms a viscous dopc, tlre iets enrercinr into agaseous or liquid environment containing a ihairr cxteirtlir which

Spaldex fibres nray be spun as ntonolilaments. or as multi-li lanrent yarns in tvhich a nuntbcr of finc filamcnts have coalcscc<lafter spinning. Square section monolilaments may be produccdby extruding sbeets and lhcn cutting lhcse into filaments.

An important feature of spaudex fibres is that thcv mav bcspun in very fine filanrents. The finest rubber yarns are iommonlyofabout 167^dtex (150-den), but spanrlex fibres nraybeproduccdas 44 dtex (40 den) or finer.

PROCESSING

diffuses into the fibre and reacts. The pie-polynrer nrolecules arelinked into their final fonn, producine tlre

'branched or cross-linked into their final fonn, producing

linked polyurethane in fibrous forrn.lirrked polyuretlrane in fibrous form.

ScouringFabrics containing spandcx fibre may be scourcd with anemulsified solvent such as perchloroethylene at about g2oc..l.hc


fabric is after-scoured in a fresh scour bath containing detergentbut no solvent, to relrove the last traces of solvent and finish.

Bleaching or Whitentug

Bleaches may be used on fabrics containing spandex fibres, butcare should be taken in the selection of the bleach. Individualspandex fibres differ in their reactions to different bleachingconditions. Hypochlorite and sodium chlorite bleaches generallycause discolouration, and peroxide or perborate bleaches arepreferred.

Optical whiteners may be used on spandex fibres, but theyshould be chosen carefully to provide optimum light fastness.Optical whiteners should be selected which give a colourlessresidue after the whitener has been broken by light.

Dyeing

Spandex fibres generally have a marked afllnity for a wide rangcof dillereot types of dye, but colour fastness is achicved onlywith dyes substantive to the Rbre. Basic dye sites on the fibreprovide for bonding of the dye molecules through the acid groupsin the acid dye. Greater fastness may be achieved by the use oftop-chrome acid dyes, but the colour obtained with these dyes isless brilliant. Disperse dyes are also used, especially where colour-fastness is not critical.

Finishing

After whitening or dyeing, a rcsin finish may be applied tospandex-containjng fabrics to improve hand and body. Certainspecial finishes which provide good whiteness retcntion onexposure to atmospheric fume contaminants are recommendedfor white or lightly-dyed fabrics. They provide good protectionin severely contaminated atmospheres.

Hcat-SctairgSpandex fibres are thermoplastic, and may be heat-set like otherthermoplastic frbres. Heat-setting is used to ensure dinrensionalstability of fabrics and garmenls.

The reaction to heat shown by spandex libres is comparableto that of most heat-settable man-made fibres and no specialhandling short of variation of conditions is required. Fabrics

* t 'I rT - "

I' l l ' l I

621

I T | --[

B : S Y N T I J E T I C F I A R E S

requiring heat-setting should be handled with the followin!principles as basis:

.(I) Tempcratures should bc kept as low as possiblc. cor.tsistcllwlltr enectlve settrnc.

(2) Tension sloJd U" kcpt to a minimum, corrsistcnt withcontrol of fabric dinrensions.

(3) Exposure time should be balanccd wilh tcnrncrtlurc toavoid over-sctting wilh a consequcnt dccrcasc in powcr.

- (4)_ Heat-sctting should not in principlc bc uscd to conrpcnsatclor shortcomings in fabric construction and manufacturc-


Fine Slructure and Appcaratce_

Molccular StructureSpandex fibres may be regardcd as ,block'copolyntcrs in whichlong llexible scctions of the nrolccule are joincci by urclhanc linksto shorter sd{fer sections. The chcmical structurc irf thc polynrcrsmay be varied through an infinitc rangc, to providc nbies ofthe desired characteristics. Modern spanrlex Iibrcs arc dcrivcdusually from low molecular weight polyethers or polycstcrs(macroglycols).

When the polynrer is spun into libres, lhe nrolcculcs arcestablished in a state of random disorder. If a strctchins forcc isapplied to the fibrc, thc folded or coiled scctions o[ thc molcculcslend to straighten out and bccomc aligncd.'fhc slrort, stil l scclions.however, are bonded to one another by intcrmolccular linksderived from hydrogen bonds or van der Waals' forces. Thcscbonded regions act as 'anchor points' which prevent the molcculcssliding past each other to take up new permancnt positions rclativeto one another.

The distortion of tlre fibre under thc tction of thc strctchincforce is thus limited to thc extcnsion pcrnriltcd by the straightcniing of the folded molecules. When the slretching forcc is rclcuscd,the molccules revert to their foldcd statc, and thc libre rcturns(ideally) to its original lcngth.

The segmented polyurethancs have two characl.eristic fcaturcswhich explain their superior physical propertics rclativc lo con-ventional rubber structures.

FF.F N N F,T:FF, F. F,F. N F-F-FH A N D B O O K O T T T E X T I L E F I B R I ] S

First, the long-chain polyurethane molecules are synthesized

from preformed, soft-segment polymer blocks, and. the hard

seeme;b forming the tie-points are spaced more regularly along

thi chains than those in randomly vulcanized rubber' In rubber,

ihe occuuence of tie-points close together may limit the flexibility

and hence the elastic effectiveness of the in-between soft-segments;

rhis is avoided in lhe case of the segmented polyurethanes' Also,

the more regular network of the polyurethanes should result in

greater elongation before breaking, by minimizing the number of

ihains which are stretched prematurely to the breaking point'

The second characteristic of polyurethanes is the occurrenceof iie-points which may be broken and re-formed during stretch-

ing. This behaviour minimizes the concentration of points of

stress, leading to an even more regular network structure with the

advantages outlined above.Finally, the hard-segment bonding is not necessarily limited.to

the tying together of molecules two-by-two, as is thc casc with

covalent crosslinks. The effect of multiple hard-segment'packages' provides additional reinforcement similar to that

obtained in conventional rubbers by the use of active fillers,

such as carbon black.

Fibre Fornt

Spandex fibres are produced as monofilaments, e.g. of roundcross-section, or as partly-fused multifilaments. Monofilamentsmade by cutting thin sheets of polymer may also be produced.

EX'TREUDED MoNoFrL | :f"ti.^T*

"r*n.lillixBF?".,u r MoNoFrL

Spandet Fibtes : Crost-scctiolts

622

'JB : S Y N T H E T I C F I B R E S

Spandex fibres are conrmonly clear and ncar-transparent, {rrwhite. The colour nray deteriorate sonlewhat with rgc.

Tcnacity; Tensile SarengthBecause of their segmented structure, spandex fibres nray bc nrldcstronger than natural rubber li laments. The brcaking tenaciticsof spandex fibres are 4.9-8.8 cN/tex (0.55- I .0 g/den), conrparcdwith 2.2 cNi tex (0.25 g/den) lor natural rubbcr.' lens i le

s t rengths of thc sparrdcx f ibrcs arc in t l rc rarrqc ( r l ( r -994 ke.lcnt2 ( 8,8-00- 14,200 ib/in2 ).

Tensile properties are aflectcd only slightly by w{rtcr.

ElongationIt is a characteristic of spandex fibres that they are capablc olbeing stretched to several timcs their original length. Thc breakingclongations range from 450 to 700 pcr cent and may vary accord-ing to dcnicr wilh thc sanrc typc of spandcx [ibrc,

Left attd upper right: 'Ly.cra'. Bottom right: Gktspan S 5bzJ

o .7

o .6

n o . 5

-9 o.4

F ^ ^

o .1

o

H A N D D O O K O F T E X T I L I ] F I B R E S

Elastic RecoYery

Spandex fibres have a snap-back rubber-like elasticity, butrecovery from stretching to a given extent is not usually as com-plete as in the case of natural rubber. In some fibres of this type,there is a small residual extension which is not recovered afterstretching, i.e. a degree of permanent set. This is not usually aprogressive .effect, reaching a constant value after a few repeatedcycles of loading and unloading. The 'permanence' of the set isalso a matter of degree; the set gradually diminishes with timewhen the fibre is allowed to relax. Recovery is speeded up byincreased temDeratule,

o 100 200 300 400 soo 600STRAIN (% ELONGATION)

Load-elongation curves for spandex and rubber libres.

d

l

624 625

' . l r f r l r l r-.l

B : S Y N T } I E T I C F I B R E S

This time-recoverablc sct is a rcsult of tenporary dcformationof the molecules as a result of the viscosity of thc systent, rathcrthan being due to molecular flow. Gcnuine 'pcrmancnt set' isinduced by stretching the Rbre so far that ruplure of some o[thc intcrchain lie-points occurs. 'fhcsc bonds rc-form aftcrrnolecular {low has ttken placc, and causc an uilrccovcrcd strain.

As seen in the tablc below, sct incrcases with lhc dcgrcc ofstretch in the casc o[ 'Lycra', particularly abovc a strctch of300 Der cent-

Set Indtrccd by Vuiorrs Dcgrees ol StrctchGlospart 57 arul 55; 467 dtex 1420 den)

Set (per catt ),s5 s74 2l 0 52 9 t 340 16

Norc. 'fhe fibre was cyclcd fivc tintes on'Instron' tensile tcstcr to designatcd strctch. Sctexpressed as increasc irr original lcngth o[ fibrc.

Stretcll (pcr c( t\200300500600

Modulus of Elasticity

Spandex fibres havc a low nrodulus of elasticity, c.g. abontl/1,000 that of I convcntional 'hard' f ibrc such as nylon orcotton. They havc a higher modulus of clf lsl icity than nrturalrubbcr, however. To achievc a givcn strctch, spandcx fibrcsrequire a force twice as high, over the cntire rangc of elongation,as the force requircd by rubber.

Spcciffc Gravity

1 .2 to 1 .25 .

EIIeca of Moislurc

Most spandex fibres have a ntoisture regain of thc ordcr of 1.0to 1.3 per ccnt ( 'Vyrcnc' has a lower than avcragc rcgain ofabout 0.3 per cent).

F.F'F.F.FJ' F-F, E F. t F. F. 1"L f'l- F F-F,| i l I" f ,

! ' " A N D B o o K o F T E x r r L E F T B R E s { B : s y N T t t E t l c F t t R E s

3 0

1 . O

200 300 400STRAII ' I I% ELONGATION)

Typical stress-strain curves for spandex fibre ('Effective tex' isthe tex at the point of measurement).

Thermal Prope ies

Spandex fibres are commonly thermoplastic, sticking becomingnoticeable in some cases as low as 150'C., but in others as highas 280'C. Melting points are in the range 230-290'C.

Ellect of Sunlight

Resistance generally is excellent, with discolouration occurringin some cases on prolonged exposure.

Effeca of Age

Spandex fibres show litt le deterioration on ageing.

626

2 .O

IL , 1 . 5

ls t and 5lh

PER CENTSlrcss-St tain DiagraDt, Spatdex Fi lttc (' V l rcut )

' fhis diagram shows the strcss-slrain relat ionships of a 'Vyrcnc'

spandex nbre, 75's count, f i rs1 and sixth cycle of cxtcnsion. ' lhc

modulus is higher than tbat of a rubber tlrrcad.-Laslc.t Yant e dLoclrotr Thrcad Ltd,

Chemical Properlics

AcidsResistance varies according to lhe typc of spandcx fibrc, Mostfibres have a good resistance lo cold dilutc acids, but rnay beattacked under more severe conditions,

AlkalisResistance to alkalis is generally good.

GeneralGood resistance to most common chcmicals, including cosmcticoils and lotions. Good resistance to oxygen.

627

I l A l . ' D B O O K O F T E X T I L E F I t l R E S'l-hc

rcsislancc to blcachcs is gcncrally good, but sonlc carcis nccessary in the selection of bleaches lor use with specilicfibrcs. Discolouration generally occurs, lor examplc, when hypo-chlolites or sodiunt cblorite bleaches are used, and petoxide andperborate bleaches are preferred.

Ilflect of 0rganic Solvenls

Spandex fibres havc a good resistance to most contmon solvents,including dry-cleaning solvents. They nray be affected by pro-longed exposure to unsaturated hydrocarbons, but are notgcnerally allectcd by saturated hydrocarbons.

Insecls

Completely resistanl.

Micro-organisms

Completely resistaDt.

SECMENTED POLYURETHANE (SPANDEX) FIBRES IN USE

Gcneral CharactcristicsAn elasiic fibre is characterizcd by a high breaking elongation(in excess of 100 pcr cent, ard usually 450 to 700 per cent), a lowmodulus of elasticity (about l/1,000 that of a conventional ,hard'fibre such as nylon or cotton), and both a high degree and ahigh rate of recovery from stretching. The following table liststypical properties of a spandex fibre, rubber and nylon.

7'e nacily Elongation It4 od ul us ol Recovery lront(cNftcx) (per ccnt) Elasricity 100 par cent

(cNltex) ttretcttU)er cetll)

Spandex ('Lycra') 8.0Natural rubber 2.1Textile nylon 37.l

0.4o.2

220.8

Because of their segmented structure, spandex fibres may bemade stronger than rubber fibres. To achieve a givel str€tch,spandex fibres require a force twice as high, over the entire rangeo{ elongation. as the force required by rubber. In contrast to a

959'1

55054026

628

r l r l

I } : S Y N T H E - r I C F I N R E S

harti l ibrc such as nylou, howcvcr, spandcx fibrcs havc l vcry lorvmodulus of elasticity.. In many of the applications for elastic fibrcs, onc of thc mostinrportant propcrties is rccovery forcc aftcr slrctching ,,u.I p;;ii;ircraxatlon. Attention must be givcn, lhereforc, to bolh lhc,loird.and the 'unload' cycles in the strcss-strain curvcs. .Ihcrc

is alime-dependcnt differencc in stress bctwecn loacl ancl unlond cvclcsrcsult.ing in a loss of cnergy which is dissipatcd by hcat.

Ihis hysteresis results fronr R strcss dccay wLich rcachcs abonstant _yalue after rcpcated cycling, no cirange bcing notcdbeyond the.fifth cyclc. Thc hystercsis allccts noi only ,'c.ovcrylorce but also degrce of rccovery.

The lack of recovcry, usually refcrrcd to as,set'is onlv nartiallvpcrmxnent. lf thc fibrc is allowed to rclax conlplctcly, tt " ."idiminishes gradually witb timc... Ilecause of strcss dccay and sct as faclors in recovcry forcc,ii ts necessary to asscss yarns rrndcr condilions which approximntcthc dcgree of stretch and cycling thc yarn will unrlcrto durirrcmanufacture into fabrics, and during wlrr. l.hc cxtcnt*of strciclf,required in elastic yarns varics according to thc lypc and rccuircJelasticity o[ the fabric into which iiis ro Uc m"nuf"ciur"AFigrrre-controlling garments, such as womcn's girdlcs, arc dcsigncdto have stretch.50 to 100 per cent grcatcr titan thc clongitionduring wear. The restraining force of such garments is r-elatcddrreclly to the recovery forcc o[ the elastic librc at its clongalionwhen it is in use.

The term'effective power'has bcen uscd for tlre recovery forccpcr unit of linear dcnsity o[ a yarn at a given elongation. Thchgure on page 632 shows the elleclive powcr of ttie du pontspandex fibre 'Lycra'and of rubber ov"r a rong" of avaii"Ltestrelch. The spandcx fibre has about twicc thc iticctivc po*ciof rubbcr.at the important clongations at which additionai ;r;rcl;oI )U to ttru per cent is availablc.. Analytical procedures, based on the principlcs given abovc,have been deviscd for predicting thc performance- o[ a yarnrncorporated in a given fabric from measurcmcnt of thc sircssslrain properties of thc yarn. For thcsc a""aur"r"ntr, t"rt-"on_ditions were established which simulatccl thc strctch "onJitioi"lo. yhit. yarn_- would bc subjectcd during nranulacture of itrctabnc. thc tollowing table shows a comparison o[ ,powcr, forthe yarn and for the fabric.

629

IFFF h hf'f'F F F lir f'' F, f: h}}ft' ; lI T A N D B O O K O F T E X T I L E F I B R E S

Corrclolion ol Efrective Power ol Yorn atd llovert Fabric

ElJective Power (cN lefrective tex )<tt'Lycra' Spandex Natural Rubbcrs\y" nT 50",', 7ty;.

Uncovered yarnCovered yarnCovered yarn removed

from fabric(3)r a n n c . ,

0.780.7 6

I . 1 5| .22

l � 1 3I . 1 0

0.360.34

0.5 I0.47

0.750.66

0.370.42

0.500.5 4

Notes.. tt) 'Effective tex' is the tex at the point of measulement.

(!) Percentages indicate actual fabric stretch, or, in thccase of yarns, simulation of in-fabric' stretch, of 50or 70 per cent.

(r) Stretchable woven fabric, 100 per cent total stretchavailable.

The data in this table show good agreement of values for theoriginal yarn, the yarn in covered form, the covered yarn afterweaving and subsequeot removal {rom the fabric, and the fabricitself.

The durabil ity of spandex fibre in garments, where flex, abra-sion, and needle-cutting are very important, is high. This dura-bility results from the regularity of polymer structure and thestrength of the interchain hydrogdn bonding. The'power'of twocommercial power-net fabrics - 467 d,tex (420 den).Lycra'and56 dtex (50 den) is virtually unchanged after 500,000 flex cyclesat elongation of 100 per cent.

The following table shows the durabil ity and dimensiontrlstability of the spandex-fibre fabric when it is subjected to cyclicflexing at elongation approaching the limit of stretch of thefabric. Spandex-fibre fabrics of two different weights show highresistance to fleK and low growth compared to their rubber-librecounterparts. Moreover, because of the durability of spandexfibres, very fine fibres (e.g. 22 d,tex;2O den) can be produced. Theavailabil ity of these fine yarns has opened up new applicationsfor elastic f ibres.

630 631

B : S Y N T H E T I C F I D R E S

FIet Rcsislancc ol Elastic Yarns in Itosicry

Cyclcs to lVaslings Growtl{tlRupture(t) (pcr ccnt)

'Lycra' spandex, 308 dtex'Lycra' spandex, 154 dtexRubber, 550 dtex

50,00050,0005,000

t'll 045

l 8l 8! 0

Nores: (r) A picce o[ sock top 2.5 cm. widc was subjcctcrl tocyclic flcxing at elongation of 100 per cent.

(,)'Growth' means incrcase in length of thc sanrplcsub.jected to cyclic flexing relativc to original length.

Clrcrnical ProperliesSpandex fibres were the nrst elastomcric fibres to accept dycstullsreadily. This dyeability results from the chcmical nnture of thcpolyurethane nrolecule, which contains activc groups capablc ofholding appropriate dyes.

Dyeability has opcned up many new applications to spandcxfibres, which were served inadequately or not at all by naturalrubber yarns. Bare spandex fibres may now be incorporated infabrics, and dyed to match other fibres in thc fabric.

As would be anticipated from the chemical structure of thcsegmented polyurethane, spandex fibres are rcsistant to hydrolysis.'Lycra', for example, retains 100 per cent powcr aftcr boiling inwater for l hour at pH 3 to ll. In addition, spandcx fibrcs havca good resistance to ultra-violet radiation, oxygcn, hcat, perspira-tion, body oils and lotions. They are physically and chcnricallystable to a range of heat, pH and reagcnt conditions such as arcused in processing operations on other libres.

lYashingSpandex fibres are not afiected by the conditions used in washingfabrics made from other fibres, and no special precautions arenecessary. Soap and detergent may be used, and garmcnts maybe washed eflectively by machine or by hand.

Drying

No special precautions are needed in drying fabrics containingspandex fibres, other than the avoidance of unneccssarily high

tii

o 50 too 150 200 250% AVAILABLE STRETCH lbeyond use dimcnsioo,

Relst ionshr'p cf 'power' to stretch beyond the trsc dimension.

temperatures. In general, the drying condii ions-may be selectedto suit the base fabric.

Ironing

It is generally unnccessary to iron the types of fabric in whichspandex fibres are used, but ironing may be carried out effectivelyif necessary. A low temperature setting should be used.

Dry Clcrning

Spandex fibres are Dot afTected by the usual dry-clcaning solvents,and garments may be dry cleaned without difnculty.

L .Jl l

I ' I A N D B O O K O F T E X T I L E F I B R E S

I

oJz

' l ' l ' l r I

D : S Y N T I I E T I C F I B R E S

lind-Usrs

Spattdex filanrents arc uscd in lhrcc fornls:( l ) Bare F i l r r r rcnts(2) Coverccl Yarns( I(3) Core-spun Yarrrs(4) Core-twisted Yarns.

Bare Filarnet sNatural rubber filamcnts arc conrmonly uscd as covcrcd yarns,in which the rubber is prolectcd and hiddcn fronr viov by Isheath of'hard' fibre suclr as nylon, cotton, ctc. Becausc of thcirhigh resistance to abrasion, whiteness, high'powcr'and inhercntdyeability, it is possible to use spandex fibres in thc uncovercd or'bare' form, and this has now bcconre cornmon practicc in ntarrysections of the stretch fabric field.

The major applications of bare spandex fibrcs arc irr thc pro-duction of foundation garments, swimwear and hosiery. ' l ' l lc

fabrics used include power"nets, tricot, lacc, and circular knils.The rapid penetration of spandex fibrc into thcsc nrrrkctsfollowed the reduction in cost rcsulting from clinrination o[ thcexpensive covering operation. All ranges of fabrics, from hcavyto lightweight garmenls are now produced.

In the power-net field, spandex fibre has not only lakcn over amajor portion of the market, but it has also enrblcd thc nlarkctto expand by increasing the versatility of thc fabrics. -l 'his

hasbeen particularly noticeable in the lightweight fabrics ainred atareas such as the teenage markct. Dyeability of sprndcx hasbeen an important factor in this respect, allowing of Lhc produc-tion of a wide range of colours and shades when spundcx isdyed, for example, in combination with rrylon.

The introduction of fine count spandex fibres and of bcanrcdspandex fibres has pernlit ed tricot mallufacturers to producc cwide range of nylon and spandex tricot stretch fabrics. Spandcxcan be knitted in combination with nylon in thc fornl of hfllf-gauge or full-gaugc warp combinations to provide a vnricty offabric textures and constructions. The fact thirt tricot frbricsare knit, coupled with the stretch of thc spandcx fibre, allows tlrcproduction of tricot fabrics with considerably |l]orc stretch inboth directions than was hitherlo possiblc.

The use of finer counts allorvs of the production of fabrics of

633


a high degree of 'femininity' for the foundation trade. A varietyof tricot fabrics rnay be created by using fine count spandexfibres under various heat-setting conditions.

Covered YarnsR.ubber filaments are covered by winding yarns of'hard'fibreround them in spiral fashion. Either continuous nlament or spunstaple yarns may be used, and two layers wound in oppositedirections are cornmonly used to provide a balanced structure.

DRIVE SPOOL

OUTSIDE COVER YARN

ELASTIC YARN

rNsrDE covER YARN -=.-*

COVERED YARN

TOP STRETCH ROLL

STRETCH ROLL

Covering elastic filaments.

634

DRIVE ROLLS

YARN PACI(AGE

635

B : S Y N T H E T I C F T B R D S

Spandcx yarns may bc covcrcd in this tashion, trsing slandardtypes of covcring machine. 'l 'he spandex yarn is slrong, unifornrand highly resistant to abrasion, permitting ths usc of very tinccovering yarns without risk of damage to the spandcx lilamcnts.

In the covering machine, the elastic li lamcnt of rubber orspandex passes through the centre of a hollow spindle whichrotates at high spced. As it rotates, thc spindlc wrrps lhccovering yarn spirally on to the elastic filament, which is hcldunder a controlled degree of stretch during the covcring operalion.

Covered spandex yarns are used primarily for thc foirndationgarment trade. Covering provides maximurn fabric powcr wilhcontrolled stretch, lhe covcr setting a Iinlit to lhc anloUllt ofstretch that ran take place. This type of yarn is nradc into porvcr-nets. woven lenos, laffetas, salins, narrow fabrics and brrri<ls.

The purpose of covering spandex yarns is rathcr <li{fcrcnt frornthat of rubber. Spandex yarns are covcrcd primarily to prcventthe slippagc of extcndcd thread within thc unstrctchcrl fabric.Where the fabric construction (e.g. powcr-nct, tricot) provirlcs asufficiently firm anchorage, then marked thrcads can bc uscd,but in ryoven constructions, for example, it is prcferablc to usccovered, core-spun or core-twisted yarns.

Core-Spun YarnsA core-spun yarn is orrc in which a non-clastic fibre sheath isspun around a core of spandex or other clastontcric yarn, 'fhistype of_yarn is made by introducing thc elastomerii fi lamcnl,stretched to a carcfully-controlled dcgrcc, into the spinning framcwlrere staplc fibre is bcing spun, in such a wiry that thc staplcfibre is twisted into a yarn with the elastomcric filament forminga core. Any type of staple fibre, such as co .on, wool, acrylic-,polyester, etc., may be used in forming thc spun sheath, and'alitypes of spinning systems may be used.

The power and stretch of the resulting yarn depend upon thcdenier of the elastomcric yarn, and the dcgree oi stretch undcrwhich it enters the spinning zone. Only a comparatiycly smallproportion (e.g. 5-7 per cent) of elastomeric yarn is uscd, as arule, the_ amount depending upon the end-use for which thc yarnis intcnded.

It is obvious that the structure of a core-spun yarn is differcntfrom that of a covered yarn made by applying spirally-woundyarns to an elastomeric core, The core-spun yarn may bc madc

H A N D E O O K O F T E X T I L E F I D R D S

IN ROVING FORM

SPANDEXDRAFT ZONE

CORESPUNYARN

\ ,o -*,.rr*SPINDLE

Core-spinning on a convcntional spinrriug frame

in a wide variety of different forms by varying the spinningconditions, type of staple fibre and the subsequent treatment ofthe yarn.

As they cnrerge front the spinning frame, core-spun spandext'arns have a tendency to relax as the elastic core recovers fromthe stretch imposed during spinning. By using adequate tension,however, the core-spun yarn may be held in the stretched statewhile it is woven or knit into fabrics.

HARD FIBRE STAPLE

636

| [ r t r I r - l r - [

B : S Y N T I I E T I C I T I N R E S

'fhc vcrsatility of corc-spun spandcx yarns is incrclscd by thc

fact that they cirn be hcat-set. This may bc carried out cllcclivclyat temperatures as low as ll0'C., with cxposurc tinrcs of about30 nrinutes, or at higher tcmperalures for shortcr tincs.

Heat-setting of yarns or fabrics provides a broad rangc ofellcctive power, from zero lo the maximum. l'hc pro.css jsimportant because it provides a nrcans of adjusting thc elrslicproperties of flbrics to the requircmcnts of thc application.

Core.spun spandex yarns arc use<l for nraking wovcn lnd knitgoods of many types.

Woven FqbricsFabrics of a wide rangc of weights, from lawns and batistcs to

o roo 200 300 400STRATN (% ELONGATTON)

Slrcss-strain curvc lor corc-spun spandcx yr. lr ' t l conrp:lred rvith crrrvcsfor spandcx and strctch nylon.

6 ,

63't

I CORESPUNi oAcRoN/coTroN/LYCRA (7odcn.)

too% SUPERLoFTNYLON (2/70d.n.)

fJJJJJ-FJ.T- f - -I t

H ^ N D B ' . K o F r E X r r L E F T B R E . Iheavy ducks, have been made from core-spun spandex yarnswith polyesters, acrylics, polyamides and their blends with naturalfibres. Spandex of 44-78 dtex (40-70 den), for example. mavbe used for lightweight fabrics, and I 56-3 l2 dtex ( l4O-2Ad aenifor poplin or duck weights.

Knit FabricsTwo general classes of knit garments are made from core-spunspandex yarns, (l) low-power or easy-stretch fabrics, and (2)high-power or restraining fabrics.

Knitted fabrics are inherently stretchable by reason of thefabric structure, but the recovery characteristics are often poor.Core-spun spandex yarns introduced into these fabrics will sup-plement the recovery properties of the knitted fabric, adding iothe dimensional stability of the knitted garment.

Spandex yarns are widely used in the warp knitting industry,where the combination of high power and low weight is advan-tageous,

The production of Raschel power-nets for foundation garmentsis a maior outlet for spandex fibres.

638 639

N FA : S Y N T H E T I C F I A R E S

6. MISCEI,LANDOUS SYNTHETIC FI8Rr6

GLASS FIBRES

Fibres spun from sodium calcium silicate and relatcd substanccsforming the materials known commercially as glass.

INTRODUCTION

The knowledge that fibres could be made fronr glass is probablyas old as glass itself. Molten glass is viscous l ike trcaclc, and onbeing touched with anything, it wil l 'string out'to fornr a fi lamcntwhen it is drawn away. As glass is in a molten condition durincits manufacture. these fi laments must have bcen discovcrcd alan early date. Nature herself produces glass tibres of this typcfrom nroltcn volcanic glass that is spun into l ibr.cs by thc wiud.

The ancient Egyptians were skilled in the art of drawins coarscfi lamenls from rods o[ ghss made by roll ing moltcn glrsi wilh ametal bar. The rods, about as thick as a pcncil, wcrc rclrcirtcd atone end, f i laments being drawn away front the moltcn material.These coarse fi laments were used to ornalncnt glass vesscls in thcNew Kingdom from about 1600 r.c. They can be regardcd as thclirst synthetic f ibres made by man.

The Romans perfected the art of using glass fi lanrcnts fordecorating their glassware, and developed a tcchnique in whicha glass vessel was spun on a potter's wheel, drawing olT glass fi ln-ments from a nrolten rod so that the fi lamcnts wcrc woutrdcontinuously on to the rotating vessel.

ln the sixteenth and seventeenth centuries, thc great Venctianglassmakers mastered the art of glass fi lament manufacturc whichthey, too, used for decorating their glasswarc. Even at this tinrc,howevcr, there was no real attcmpt bcing rnade to usc gltss fi la-ments in texti les, despite the fact that the manufacturing tcchniqucof producing the fi lanrents had rcached a high degree of pcrfcc-t ron .

Robert Hooke; Re i-At oi,te Ferclnult tle RttrurtturIn his pubfication Microgrqphia (1665), Robert Hookc, thcfamous English physicist mentioned the drawing of f inc fi lamcnts

H A N D B O O K O F T E X T T L E F I B R E S

from a heatcd glass rod, and speculated about the possibility ofproducing synthetic nbres.

In 1713, the French physicist RenC-Antoine Ferchault deRiaumur described the making of glass filaments for the manu-facture of imitation heron feathers: Two men work together, theone heating a piece of glass over a flame and the other pluckinga nlament from the softened glass with a glass hook, which heattaches to the rim of a wheel like that used for spinning, andthen reels up the lilament by revolving this wheel rapidly.

Riaumur speculated as follows on the possibility of using glassfilaments in textiles: 'If we knew how to manufacture slassthreads as ptiabte as lhose in which spiders envelop their iggs,these threads could be interwoven. Even if glass is not pliable, itcannot be said-to use the expression-that it is not .,textile".'Rdaumur experimented in the production of fine glass filaments,and succeeded in making lilaments finer than those of silk. Theywere, however, very short.

Incontbustible Class Fibre Lomp llicksThe comparatively coarse glass fibres which were produccd atthat time were so brittle as to be of little value in varns or fabrics.and their applicalions lay outside the field of textiles. In 1822, forexample, the use of glass filaments in the production of incom-bustible lamp wicks was patented by two British inventors, Alex-ander and David Gordon.

Early S pinneret ProcessOne of the earliest references to the use of glass filaments infabrics is found in a report issued in 1842. It descr.ibes glass fila-ments and fabrics made by Louis Schwabe, a prominent Man-chester silk weaver and supplier to Queen Victoria and the FrenchCourt. Schwabe developed his own technique of spinning glasslilaments, and his machine was demonstrated at a Manchestermeeting of the British Association. It produced glass filaments bydrawing molten glass through small orifices, and may thus havebeen the forerunner of the modern technique of spinning man-made fibres by extrusion of liquids through spinnerets.

Old Method ol Spinning GlossFrom the end of the eighteenth century onwards, glass filamentswere commonly produced by the old technique of drawing them

' l r l , l r l r l r l


!::l ff iq"*I!1"1"$T;,,.."*,Inif ?u:ll, ?lr ;i,il,.,lll]9-t11 *htol was. kept ru.rning at abour 650 ,.p.. ty n "oit_

ii'!iil!ii'',: itf." jl:li ",i:il:, Ll :H n.l ;i i f i, iTi",,-, xiidfl';"'*:-1"*,;oi,:"1;:i;:,#-lli;n.*#xl.,Txi:jiias 6 microns diameter.

N i net eent bC e nt ury B i cont pottent G lqss F i breThe glas filament spinning process described above is stil l uscdloday rn scarcely modified form in the cottage ln.fustri"s--oiil,"Thuringian and Bohemian forests, to make the _"dium-nne-nl,iments for'Angelt Hair' and other Christrnas_rree ;;";;;ii;";l-'Angel's Hair'is interesting as an early """.p1" ;i ' i;; 'L;;;rn_f ?l:nt. qb* which is becoming of er""i' ini-"ri'L;;;'?s;';;;;

ii t :i,il:',xfil?ll"*, ""i'f;n"ill,:l fi:lii,'jTil,:i:,.1,Jiljlfwelded a strip of platc glass. Th

n li': ;*i:i;l ;i,fi it f ix'tr ffi i":t3l":?,f, : if"":ilil; "1li:During-the mid-nineleenth century, the use of glass filamcnls

S*"::Tf ht" l?"l""TX?iY,l"li"s'. hars'^ *art-co;;;s;' "i;;:

st;"f '[T"il:'J:n, ]t;: ';il.:l iiil p;{nl[i",f-t'Hijand a. glass thread wefr (filling) for tf,"- er"rf"r"

'ri"i "rlilCreorgia Cayvan. A similar'dresi was made fo. p.ln"".r''grf"ii^

iT,!l_'!4q:,J"i'Td:,in.Ift ,;l"ilffi,,,ffi ;'ir|;:\:ijf;lf "^.'"11i'.*::,H',i"#,"1il:J.;.l.il j*X*i*iru;i::A -description of the melhod of rn"nufo"tu.ing-;i;;.

';iiil;i;an<I_fabrics at the end of the nineleenth """tr.'y ;;;;;; ';;;;,1897 issue of the German periodia workshop *;,-";;;;;; "r-h.;;:3H"!1ft

,rT ljli ii"_l,",Jiiiti:'1:1u1ii:ii1i1,,11,il:n,nlr"tn*xi:$;;j:-T:::X',::,ij,',i3',il"i3l$i;?il j::Tt"J"_.".*Xlii;;lf

641

I

i

r ' l r - l

fffrFjql:FF.1 metres (13 fcet) in diameter and revolving at 400 r.p.m. Whertthe cylinder is full of spun glass the filament is transferred tosmall spools which can be inserted in shuttles. The glass filamentis combined with one of silk to make the weft in a fabric with asilk or cotton warp. The looms used for this weaving are handoperated and have Jacquard heads. Furniture and clothing mater-ials, umbrella and necktie fabrics are woven in the public sight.Bu! a metre of curtain material, for instance, costs 100 francs!'

l\{odern Glass Fibres

The production of glass fl laments suitable for texti le use requiresthat they should be flcxible enouglr to stand up to normal wearand tear.

-fhis is achieved not by changiog the composition of the

glass itself, but by making the filaments so fine that thev canbend without breaking.

Thick rods of glass will bend only very slightly, but the mini-murn radius to which a glass rod or libre may be bent withoutbreaking decreases with decreasing rod or f ibre diameter. Yarnsconsisting of very fine fibres may be bent quite sharply withoutbreaking, as it is unlikely that any individual f ibre wil l be bentto breaking point when the yarn is flexed.

The early methods of producing glass filaments were capableof spinning very fine filaments suitable for textile use. But theprocesses were not able to produce uniform fine filaments at acost low enough for commercial textile applications.

From l9l2 onwards, methods of spinning glass frlamentscheapiy were developed, notably by cenrifugal processes in whichlhe molten glass is thrown from holes in a metal spinner rotatingat high speed. The early high-speed production tcchniques pro-vided tangled, coarse l i laments, however, of diameter greater thanl0 nricrons, and the fibres were not suitable for textile use.

The production of textile-type fibres presupposes that they canbe made in dianreters smaller than about l2 microns, in adequatequantit ies and at an economic cost, in the form of a continuousstrand, or of a sliver of staple nbres of adequate length, bothbeing suitable for spinDing into a yarn.

During the 1930s, this was made possible by the developmentof glass fibre production processes, notably by Owens{orningFiberglass, an American company formed by the Owens Il l inoisand Corning Glass Companies. This firm developed three pro-cesses before 1939:

642643

F F F F F }D : S Y N ' I I ] E T I C T I A R E S

(l) Conlinuous Filanrcnt Process. ln this proccss, slrands ofglass fibre of very great length (e.g. scvcral thousands of yards)were drawn fronr platinunr bushings and uscd for twisting anddoubling into yarns.

(2) Long Stqple Fibre Proccss. ln this proccss, streanrs of ghssrvere allowed to flow from a bushing bascplatc into the slot o[ asteam blower. The streanrs were drawn into long (7(r cnt; 30 in)single fibres which were collected on a rotating pcrforatcd drumwhich was kept under suction, The web so formed was drawn o{Tafter a quarter-turn of the drum and drafted into a sliver of morcor less parallel f ibres. The slivcr was spun into coarsc wooll ikcyarns and fabrics.

(3) Short Staple L-ibre Process. A process similar to (2) wrsdeveloped for the nranufacture of largc quantit ies o[ short ( l3-100 nrrn; /r-4 in) fibrcs. Streanrs ofnroltcn glass werc ttcnuttc(lby thc blowing ol slcarrr or air, brrt this linlc lhrough tl)c usc o[highcr prcssure the fibres were drawn anrl rippcd into sho/rtlengths due to the strong turbulcnce of the blowing ntcdiurn.

In processes (l) and (2), individual clcctrically-hcatcd nrclt ingunits or bushings were used, but in process (3) mctal brrshingswere fixed to the forehearths of big glass-nrelting tanks. lt is onlyin comparatively recent t imes (1950s) that tcxti lc bushings havebeen fixed to glasslaDks lor the production of continuous fi la-mcnt glass yarns.

Fronr 1938 onwards, the traditional proccss o[ drawing glassfi lan'lents from rods was also perfected by Glas-Wollc K.G.W.Schuller and Co. (Germany) and other firms. Spccial proccsscsfor the production of superfine filaments with diamctcrs of I to 3microns have since been developed, e.g. by Owcns-Corning Fiber-glass and by the S.A. des Manufacturcs des Glaces de Saint-Cobain, Sociit i du Vcrre Texti le.

These modern methods of spinning glass fibres havc opcncdthe way to the manufacture of glass yarns and fabrics suitablcfor a wide variety of industrial, furnishing and apparcl uses. Thedevelopment of new types of glass has increascd tlre vcrsatilityof glass fibre, and extended sti l l further its potcntial nrarkct.

Between 1937 and 1967, the glass fibre industry cxpandcdthree-fold, and it continues to increase. Init ially, glass fibrcs wcrc

liI ] A N D B O O K O F T E X T I L E F I B R E S

uscd largely il l insulation and liltralion applications. Thc intro-duction of glass-libre-reinforced plastics brought a new marketwhich is still expanding rapidly, and the acceptance of glass librcinto genuine textile applications is making steady headway.

TYPES OF GLASS FIBRE

Glass is made in a wide variety of diflerent compositions, andRbre may be spun from virtually any glass to provide materialsuited to particular applications.

ln general, there are two main types of textile glass fibre inlarge-scale commercial production; 'E' glass and'C'glass. Bothtypes are similar, but each is designed to serve to advantage inspecific end-uses,

'E' Glass is a boro-silicate glass of low alkali content. It hasa very high resistance to attack by moisture, and has superioreleclrical characteristics and high heat res.istance.

'C' Glass has superior resistance to corrosion by a wide rangeof chemicals, including acids and alkalis. It is widely used forapplications where such resistance is required, e.g. in chemicalfiltration.

Glass wool fibre for non-textile applications is also spun fromglasses of other compositions. Continuous filament is spun from'A'glass (alkali glass; window glass).

FORMS OF CLASS FIBRE AVAILABLE

Glass fibre is produced in two basic forms; continuous filamentand staple fibre.

Continuorc FilanlentContinuous filament glass fibres are made usually from 'E glass.They are produced in a range of filament diameters, with an upperlimit in the region of l2 microns (for textile applications). Theincreasing brittleness of filaments of diameter greater than thisrenders them of littlo value as textile fibres. Textile glass filamentswith a diameter as small as 2.5 microns are commercially avail-able ('Beta' fibres) and filaments of diameter I micron and lessmay be made for special applications.

644 645

, r l

s t r i rnds4,000

Class staple fibres are made usually from 'C'glass. Thcy are pro-t lucct l in a rauge o[ f i larncnt counts an( l lcngths, c .g. l ror l 20*38 cnr (8- l5 in) .

Cornmercial ProduclsGlass continuous filament strands and staplc fibre arc commonlymarketed by the manufacturers in a variety of madc-up forms.

Con!inuous Filattrcnt YartThis is made by twisting and/or plying a numbcr of continuousIil$nent strands. Thc numbcr which arc twistcd or plicd togcthcraflcct the yarn's strength, diametcr and flcxibility.

Continuous filamcnt yarns are conrmonly sizcd (c.g. 2 pcr ccntstarch-oil) to facilitate subsequent handling and fabrication opcra-tions. They are also furnished in a varicty o[ treated fornrs, e.g.dyed, waxed, pre-saturated, vinyl-coatcd; thcy may also be com-bined with other textile fibres.

Continuous ,ilament yarns are fabricated into cords and scwingthreads. They are widcly used, for examplc, as reinforccmcnt inelectrical insulation nraterials, wirc and cable, plastics, ctc., asfiltration materials, and in decorative fabrics.

Staple Fibre YantYarns spun from staplc fibre are wovcn irrto fabrics uscd lor wctand dry filtration operations. They are uscd also as reinforccmcntin conveyor belts handling hot materials, and as braids in clectri-cal insulation applications.

Staple libre yarn is commonly supplied in combination withflame-proof waxes, lacquers and comnrcrcial insulation varnishcs.

JlaDle JItver-Ihis is a low-cost wadding matcrial. lt is used, for cxamplc, inaquarium Rltration applicalions. Woven into fabric, it providcselcctrical turbine generator thermal blankets.

B : S Y N T I I E ' T I C F I I } R [ , S

Continuous filanrcnts arc produced in thc fornt o[contairring nrarry individual filanrents-e.g. from 5l todepending on specific rcquirenlents.

Staple Fibre

I

I r- t- r- a .. - - - - - l '-r, - r, - - - - r,F

t . I I i

I I t I i I i I . I I . I , l I ' ' t t r

l [ i IH A N D B O O K O F T E X T I L E F I B R E S

Bulk St.tple Fibre

A fluffy, bulky libre that is used for air and liquid filtration,pharmaceutical wadding and dunnage.

Fine Fibres-Unbonded

A mass of soft, fluffy fibre, ranging in diameter from + to 3 mic-rons. They are used for'all glass'papers and high efl iciencynltration applications.

Bonded Staple Sliver

A ribbon of parallel libres bonded together with an alkyd resin.It is used as a filler, and also as an outer braid for many electricalcable applications.

Cordcge

Cordage is made by iwisting, plying and cabling continuous fi la-ment yarns. lt is commonly available in a variety of diametersranging, for example, from 0.4-4 mm (1164-10164 in). It naybe untreated, or treated with various coatings.

Cords are used in cable wrapping seals, reinforcement ofhigh pressure steam hose, etc.

Sewing Thread

Sewing threads are made from very fine continuous filamentyarns. They have the highest teosile strength, flexibility and resis-tance to high temperatures of any textile sewing thread.

Scrim

This is a low-cost. non-woven reinforcement fabric made frorncontinuous filament yarn in an open mesh construction. It ismade by coatiflg length-wise yarns with a hot-melt adhesive andapplying cross-yarns while the adhesive is sti l l motten. Asphftltbase and polyethylene adhesives are used, for example, in makingscrim.

Glass fibre scrim is moisture-resistant and rotproof. The glassyarns provide exceptional tear and tensile strength in two direc-tions, and materials reinforced with glass fibre scrim have a veryhigh dimensional stability.

Glass fibre scrim is available in a wide varietv of sizes. It

646 64't

E : S Y N T I I E T I C F I B R E S

can be combincd-in the lanrinating and cxlrrrding proccsscs-with paper, f i lm and foil. The resulting producls arc uscd cxtcn-sively in the packaging industry.

Mat

A non-woyen material used primarily in plastics rcinforccnlcnl.It is distributed in a random paltcrn to cnsurc nraxinrunr urri[or-mity in thc finishcd lanrinatc. N4ats are lrcrlcd wilh variousbonding resins to proyide optinum compatibil i ty with thc lanrin_ating resin, and the dcsired handling and fabrication charactcr-istics.

There are several types of mat available:

Chopped Strand Mar consists of choppcd strands bondcdtogether by a resin. It is used in most applications of rcinforcctlplastics usually when large and complicatcd shapcs arc to bcrnadc. Exanrplcs arc corrugatcd shccts, bonls, nrotor cirr botl ics,building components, containcrs and thc Iike.

Continuous Slrqnd Mat consists o[ uncut continuous stratrdsheld together in sheet form by a bonding resin. lt is uscd mainlyirr matched metal die moulds, where relatively decp arrd compleicontours require maximum'draw' charactcrislics.

Neccllcd Mat consists of cut strands which are nccdlcd lo acarrier t issue. It is used where a particularly bulky rcinforccnrcnlmat is wantcd.

Bonded Mat or Stoplc Tissuc is a thin highly porous nrat rnl(lcfrom monoll laments of type'C'glass arranged in a vcilJikc pat-lern. This mat is nsed mostly in thc rcinforccrncnt of bilunrcnwhich is applied to buried pipes as protcction against corrosion.It is also uscd as a surfacing mat on top of olher rcinforccmcnlmalerials to producc a smooth rcsin-rich surfacc.

Rovirtg

This is a low-cost, high-strength rcinforcemcnt matcrial nrade bygathering a number of continuous fi lantent strands and windingthem into a cylindrical package. It is availablc in two forms:continuous strand roving and spun strand roving.

II I A N D B O O K O F

' T E X T I L E F I B R E S

Corttittttotts Strond .Roving consists of parallel strands whichprovide high unidirectional strength.

Spun Strand Roving- This roving consists of one or morecontinuous strands looped back and forth upon themselves.It is held together by twisting it slightly and applying a cohesivesizing. The roving has less unidirectional strength than continuousstrand roving, but it posscsses greater bulking characteristics.

Continuous strand rovings are used in processes where they arechopped into short lengths. These chopped strands give a non-directional reinforcement to plastics similar to chopped mats.

Rovings can also be woven into fabrics, continuous filamentrovings giving higher strengths and spun rovings better interlam-inar adhesion.

Rods and other profiles can be produced by dra'wing resin-impregnated continuous and spun strand rovings through dies anda curing oven. Rovings may also be wound on to fornters whichcan be rotated to provide cylindrical vessels and similar bodiesrvhich possess great strength. (Filanrent Wincling).

C lropped StrandsThese are available in a wide variety of fibre lengths. They areused as a reinforcement for resins, and for reinforcing putties,caulking compounds and foam rubber. They are also used forgypsum wallboard reinforcement.

Milled FibresThese are made from hammer-milled continuous filament strands.They are used where shorter fibre lengths are required for rein-forcement applications.

Fabrics and TapesThese are made from continuous filament yarns, rovings andstaple yarns, by weaving on conventional looms.

'Broad fabrics' refer to woven glass fabrics 46 cnt (18 in) orwider.'Narrow fabrics'or tapes refer to woven glass that ranges inwidth from 6.4-200 mm (lzr - 8 irD.

Fabrics and tapes may be processed through moulding, laminat-ing and coating techniques. They are used in applications requir-ing the most exact control over thickness, weight and strength,

648

L ' L U U L _ I _ U \ J U

B : S Y N T T I E T I C T I N R E S

includiug intlustrial fi ltratiou, clcctric:rl insulation antl tlccorativt,fabrics.

D oug I t M oulclirtg C onr po undI'his is a mixture of short glass fibrc stralds rvith rcsin rntl l i l lcrs,rvhich is dried but not curc(1.'l 'hc conrpourrrl is finllly curcrl bythc lanr inator in nrr tched nrcta l t l ics rv i t l r thc appl icr t ion of hcat .

NOMENCLATURE

Classes used for the manufacture of fibres arc either sodaJirnc.silicates or boro-silicatcs (such as 'E' or 'C' glass). Othcr matcri lscan be added to the silica network to modify the propcrtics of 1heresulling glass.

For this reason, it is not possible to givc a gencral chemicalformula for glass fibres, but each glass composition from whichthey are drawn may be accurately dclincd in chcmical tcrrns bythe ingredients which go into the melt.

Iicdcral Trarlc Conrnrission DcfnilionThe generic tcrm g/ass was adopted by thc U.S. Fcdcrrl -l'radc

Commission for fibres of this type, the omcial dcftnitiorr being asfollows :

Gla.rs. A manufactured libre in which the fibrc-fornrinc sub-stance is glass.

PRODUCTION

Glass Manrrfaclurc

Glasses of many dilTerent compositions are made by thc glass in-dustry, the type produced being selectcd to suit thc end-uses forwhich it is required. Silica sand (silica) and limestone (calcium

649

: - - - - - - - - - -

H N D B O O K O F T E X T I L E F I B R E S

carbonate) may be regarded as basic ingrcdients, to which areadded varying anrounts of otber materials such as soda ash(sodium carbonate), potash (potassium carbonate), aluminiumhydroxide or alumina (aluminium oxide), magnesia (magnesiumoxidc) or boric oxide.

The glasses commonly used in making textile nbres-'E glassesand 'C' glasses-are made from compositions of the followingtyPe:

'E GlassAmount (N, approx.)52.5-53.516.5-17.54.5-5.5

14.5Less than 1.0I0.0-10.6

Anount ("/,, approx.)62.0-65.06.01.0-3.01 . 0

I 1 .0,15.03.0-4.0

charged into a furnace, whete they arefused at high temperature, forming molten glass. Filaments maybe spun direct from this melt, or the glass may be formed intomarbles of l6 mm (5/8 in) diameter. The marbles are inspected, andany that contain impurities are discarded. The others are thenpassed to the spinniug machines, fiberizing units or'bushings' aslhey are called in the glass fibre industry.

Fiberising(A) Continrous Filament Process

Continuous nlament strands are produced by allowing moltenglass to flow through perforated tips on the baseplate of a plati-num melter ('bushing'), drawing away a stream of glass from each

ltryrcdientSil icaLinrcMagnesiaAluminaSoda; potashBoric oxide

' C ' G l a s s

IngredientSil icaLimePotashAluminaSodaBoric oxide

The ingredients are

650 651

n - - nB : S Y N T T I E T I C F I B N E S

lip to form a fibre, and attaching thc fibrcs to a high-spccdwindirrg collet. The btrshings may be nrounlcd on ttosrln,"itiuotanks. or lhey may forrn lhe basis o[ independcnt fiberizinc units]being fed with glass by remelting glass marbles.

As the 50 or more nlaments are drawn from the oriticcs. thcvare brought together into a strand. A lubricaling sizc is applicrlto facilitate subscquent processing.

If the strand is to be used for rcinforcenrcnt of plastics, thclubricant or size will be chosen to be compatiblc wiih polycstcror epoxide laminating resins, and the strand may bc convcrtcdinto various forms of chopped strand mats, rovings or choppcclstrands.

If the strands are intended for use in tcxtilc werving, lheymry.be processed through convcntional tcxtile proccsscs intosuitable yarns. These yarns are available in standard basic countse.g. o f 5 .5, 11,22,33 and 66 Tex.

Thc diametcr of thc filaments produccd in this wav dcncntlsupon the rate at which the glass is drawn fronr thc oiificci, thcsize of the orifices, and the viscosity of the mclt. prodtrcrion iatcsarc ext ren:e ly-h igh, reaching J kr r r ( 1 .9 rn i les) a nt inutc l ( l n torc.une rnarb le wl l t prov j ( le as n)uch as l60 k rn ( 1 00 r r r i les ) o I l lhnrcrr t .

(B) Srqple FibreTherc are a number of methods of producing glass staplc fibrc.the most important of which may be considercd as tlrc Ccntri-fugal, Jet and Rod Drawing processes.

Certrilugol ProcessIn this process, moltcn glass is thrown out o[ holcs in thc bascof a mclal spinncr rotating at high specd. Fibrcs of this tvnc arcbondcd into a web, and are uscd in heat and sound insi,intion.This technique is not generally rrscd for producing textile gradeglass fibres.

Jet Ptocess (Steam Blowing, Batwool or Slaplefibrc proccss)

Staple hbre is produced by a process in which ntolten glass flowsunder gravity through holes in the base o[ ptatinum brrshinss. rsin the production of continuous filament. Thc strcarns o[ glais nrcthen drawn into fibrcs by the action of high-speed strianrs of

T I A N D A O O K O F T E X T I L E F I B R E S

turbulent gas or steam. The soli<til icd fibrcs are btoken by thc

turbulence in to s taples of up to 38 cm ( l5 in) ar ld co l lected in to

a web on a revolving vacuum drum.'The web.lnay tllen be guldefl

fronr the drum and drafted into the lorm ol glass staple sllver' I nrs

is l l len processed on convent ional text i le n lachines lorwcavlnSln loslass fibre staple fabrics.

Rotl Draritt-g Process

This is a modern development of the traditional process -formaking glass lilamenls. ln a typical modern machine, 125 glass

roOt, u-su-utty about 4 mm' (0.1575 inch) in diameter,-are mountedvertically and adjacent to one anothet in a so-called 'spinning

frame'. ihe rods are kept moving slowly downwards, and aresimultaneously melted at a temperature of about 1200"C', eitherbv in<tividual. movable and adjustable gas burners or by electricheating coils in a fireclay chamber. Drops of glass fall away fromthe ends of the rods, drawing glass filaments after them' These arelecl via an inclined plane on to a rapidly r-evolving cylinder{usual lv l0 l .6 cm; 40 in wide ' and rotat ing at EUU r 'p 'm' ' so taK'

ingry 2,475 m; 2.?50 yd per minutel) on to which they are wound

n"i.t io, but independent of, one another. Lateral movement ofthe spinning frame next forms a glass nlament -web-on.thecvlind-er. from which it is at intervals cut and after doublingformed by horizontal doffing and repeated slight stretching intoglass fibre slubbing.

Atternatively, the filaments are merely drawn off and out by thecylinder, not being taken up but being doffed, atter about three-quarters of a rotation, by a combined lifting and cutting apparatus'ih"ir flo* direction is then deflected and they are tossed on toa stationary sieve and collected and doffed as a glass fibre slivercomposed of fibres of unequal length.

PROCESSING

Sizing

The application of a suitable size is important when glass fibresare to 6e subjected to textile processing. The size must lubricatethe fibres to minimize the effect of fibre-fibre friction, and hold theinclividual li laments together in the strand. At the same time, the

652

' \ i l - L i L ' '_.L t ' \_ L ' L l L L ' I U U U i , ' U L i - U

B : S Y N T H E T I C F I N N E S

MOLTEN GLASS

SPINNER

+GLASS STAPLE FTBRE

CONVEYOR

( I ) STAPLE F IBRE.CENTRIFUGAL PROCESS GLASS MARI]LES

FURNACE

MOLTEN GLASS

HIGH PRESSURESTEAM OR GAS JETS

GLASS STAPLE

MOLTENGLASS

SLIVER

SPINNINGMECHANISM

YARN

FILAMENTSslzlNGSPRAY

(2) STAPLE FIBRE,JET PROCESS

SPRAY --:__j_.-::]-=_.

CONTINUOUS FILAMENT

Glass Fibre Production. Three important mcthods of nraking glirssfibre are sbown above,(l) Strple Fibre. CcntrifDgal Process.(2) S:aple Fibrc. Ict Proccss.( : l ) Con l inuous F i lamcnt .

653

,F- F- T FJJ, F T I T I,' F F F. F. T F. F. F,l l ,t ii i

- r l N D B o o K o F T E X T I L E F I B R E S I u : s y N T H E T l c F T D R E S

r size nrust not Inake thc strands aclhere in Jhc.

pn:k1gci I applicrfion of sonrc sort of coating to thc tibrc, thc coll ing trcing

i Dextrinized starch gum, gelatine, polyvinyl alcolrol, hydro- | either pigmenttd bcfore application or colourerl subsc{ucntligenated vegetable oils and non-ionic detergents are commonly I by dyeing.rrsed.

Heat-CIeaning

Glass fabrics and tapcs are usually combined with other materialssuch as coatings and resins. In order to ensure that the union ofglass with these materials .is eflective, it is usually necessary toremove the sizing that was applied to the yarn during the manu-facture of the goods. This may be done by heat<leaning at hightemperatures.

There are various techniques and conditions under which heat-cleaning may be carried out. Continuous heat-cleaning, forexample, may be achieved by passing fabric through an oven atabout 650"C. The organic material is burned away to leave thewhite fabric.

For some applications, such as the use of glass fabrics in theproduction of melamine laminates, a partial heat-clcaning may becarried out, Some of lhe organic matter is caramelized, the starchbeing converted to carbon which remains on the fabric.

Hcat-Sctting

Class is a thermoplastic material, and the strains introducedduring processing and production of yarns and fabrics may berelieved by treatment at an adequate temperature. In the Coroniz-ing treatment, for example (see page 655), dimensiooal stabil ityis conferred on glass fabrics by a heat-treatment at 650"C. Thisis a form of heat-setting but it is not a true heat-setting such asthat \Mhich occurs in the heat-treatment of a partially crystallinefibre.

Dyeing

Glass fibres absorb only a negtigible amount of water, and theiraflinity for dyestuffs is virtually nil. It is not possible to colourglass by using the normal dyeing techniques. Many specializedprocesses have been developed, however, for the colouration ofglass fibre fabrics. An early technique was to mix pigment intolhe molten glass before spinning, but this has not attained realcommercial importance, Most modern processes rely upon the

654 655

(l) Pignu atiott ol Molten GlassThe technique of adding 6nely-dispcrsed pignrents to lhc nrcltbefore spinning, as used in the production of rnany typcs ofspun-dyed synthctic nbrcs, ntay be uscd in thc colouration ofglass fibre.

In view of the high tempcrature at which glass fibrc is spun-around 1,200'C.-it is necessary to usc inorgflnic pignrcnts, Arange of prstcl shades nray be obtained satisfnctorily in this wry.

Production of spun-dyed glass libre sullcrs from the drawbaclisinherent in this process. The nranufacturer must allocatc spinningmachines to the production of specific colours, or bc picpnrcdfor tedious and expensive cleaning opcrations in changing fronronc colour to another. Also, each additional colour inciclscs lhcstorage problems, and the raDge may be restrictcd on this account.

(2) CoroniTatiotrCoronization is a system of trertment of glass fabric which bringsabout significant changes in the charactcristics of thc cloth. ltnrakes possible, too, the application o[ colour in an cfTcctivc wav.. The colouration of glass fabric by Coronization tukcs plaicin the following stagcs.

..(a) Glass fabric is passed through a dispcrsiou of colloidalsll lca,

(b) The sil ica-impregnated fabric is passed througlr tn ovcn at650"C. for 5-15 seconds. Sizes and other organic matcrials arcburned away, leaving only the finc particles ol sil ica actherinc tothe surf3ce of the glass fibres.

During this heat-treatment, the libres are relaxed an<l thc wcavcis set, thus establishing the dimensionat stabil iry of thc fabric.

(c).The heat-treated fabric is passed through a bath containinga resin dispersion, comnronly a brrtadiene-acrylonitri lc copolymci,and coloured pigment. The labric then passes through i cirringoven at 160"C.

'fhe resin is cured on the cloth, binding thc pig-

ment to the fibres.


(d) Thc pigmented cloth now passes through another-paddingprocess, in-which a solution of stearatochromic chloride is ap-

ili"a. Tnis is followed by drying in another oYen at 160"C.Stearatochromic chloride has a high affinity for glass, and it

establishes a powerful bond between the glass and the resincoating.

Coronized fabrics display increased abrasion resistance' creaseresistance and water repellency' The fabric acquires a softerhandle, antl becomes more flexible, Ageing and sunlight resistanceare improved; fabrics can be washed, and dried by rolling in atowel. They do not need ironing.

PrintingThe Coronizing process may be modified to permit the screenprinting of glass fibre fabrics. The stages in the process are asfollows :

(a) Silica treatment,(b) Heat treatment at 650"C.(c) Application of cationic softening agent to lubricate and

protect the fibres.(d) Screen printing, using a printing paste containing pigment

and resin latex which has been thickened with alginate.

(e) Curing at 160'C. for 5 minutes.(0 Padding in stearatochromic chloride, followed by drying at

120'C. for l5 minutes,Fabrics printed in this way have good washfastness and resis-

tance to crocking. They are crease resistant and water repellent,and have good drape and handle. They may be wasbed effectively,and need no ironing.

FinishingA wide variety of finishing Seatments is available for use withglass fibre goods. Most of these are intended to increase theim"i"n"y oi glass goods when used as reinforcement in plastics,and are not therefore of immediate interest in the considerationof glass as a textile fibre.

There are, however, some finishing treatments which are ofgreat importance in the eflect they have on glass in textileapplications.

656

' \ , ' 1 , , - \ , ' L u : l , . l t l - t , , 1 , , I L l i l : u L j l u t " u u u \ - i u 1

8 : S Y N T H [ , T I C F I B R A S

CoronizingCoronizing is ir l inishing treatmcnt which hrs r signilicanl cllccton glass libre and fabrics used for tcxtilc upplications. lt in-creascs the resistance to abrasion, watcr rcpcllcncy, crcasc rcsis-tance and flexibility of glass fabrics, and inrprovcs thc handlc loan inrpressive degree. It also makes possiblc thc cllcctivc colour-ation of glass material.

Corrosiorr Resist4nt FinisllDispersions of polytctr.rfluoroethylene are applicd to glass fabricsfollowed by drying and thc application of prcssure at tcmpcra-tures in the region of the P.T.F.E. sintering teNperalurc. Clothproduced in this way is used lor liltration fabrics that mr$t with.stand corrosive conditions, pump diaphragrns and the likc.

Antistatic FitrislrGlass fabrics arc hcat-clcancd and thcn dippcd in conrpositionscontaining potassium isobutyl polysiloxanolatc. Thc trcalcdmatcrial is hcatcd at 150'C. for up to 30 nrinutcs, dricd irndrinsed with dilute hydrochloric acid. It is thcn dricd and washcdin water,

Sterryllrcning FittishesGlass fabrics are coatcd with a rcsinophobic nlaterill that prc-vcnts adhesion of resinous materials to thc surfacc of thc glassfibre. The treated cloth is then coatcd with a rcsin linish, whichpenetrates into lhe interstices of the fabric wilhoit adhcring tothe individual strands of fibre. The frecdom of movcmcnt whichis left to the fibres improves the tearing and bursting strcngthsand the flex resistance of fabrics to be used in hcavy-duty fabricssuch as awnings, tarpaulins and tent naterials.


linc Slructure and Appcarancc

Molecular Stuclure

The term 'glass' describes a range of materials madctogether one or more of the oxides of silicon, boron

by fusingor phos-

657

I r r- - -

| . l - - I h _ r ! .r [ 1

t ii


phorus, with certaiu basic oxides, c.g. sodium, potassium, mag-nesiun, calcium, and cooling thc product rapidly to preventcrystallizal.ion taking place.

Class is thus a mixtule of silicates, sorne water-soluble, likesodium and potassium silicates, and others water-insoluble, likecalcium and magnesium silicates. It is an anrorphous material,in which the atoms do not take up the ordered positions associ-ated with regions of crystallinity, and it differs in this respectfrom those synthetic organic polymers which produce fibres ofpartially crystalline structure. It is a supercooled liquid with sucha high viscosity that no perceptible flow takes place,

Fibre FontrGlass fibres are smooth-surfaced and commonly of circular cross-section. They are transparent.

TenacityDry: 53-64.5 cN/ tex (6.0-7.3 g/den) ; wet :34.4-41.5 cN/ tex

(3 .9 *4 .7 gl den)Std. loop: 8.0-9.7 cN/tex (0.9-1.1 g/den)Std. Knot : 15.9-19-4 cN/ tex (1.8-2.2 g l ( len)Terrsile Strength

14,000- 15,400 km lcm2 Q\o,0oo-220 p00 1b/in2).

Dlorgaaior (per cent)

Dry: 3.0-4.0 ('C' type: 4.5)Wet : 2.5-3.5

Elastic Recovery100 Der cent

Poisson's Ra(io

o.22

Hysteresis

None

658

FF.-FS Y N T H E T I C F I B R E S

Crccp

None

Avemg€ Stillness

2,843 cN/tcx (322 g/dcn)

Spccific Gravily

2.54 ('C' type: 2.49)

Hardness

(Moh Scale) 6.5

trlTect of Moisaure

Absorbency: up to 0.3 per cent (surface)Rega in : N i t

Thcrm{l Propcrlics

Softcning point ( 'C.)Strain point ( 'C.)Annealing point ( 'C.)

'E' 'l vpe8465076570 . l 9

'c"1 1'pc

75241558i

Specinc heatFlammability : Glass fibre docs not burn.

EII€ct of Agc

None.

Itllect of Sunlight

None,

Ch€mical Propertics

Acids

Glass fibres are resistant to acids of normal strcngth and undcrordinary conditions. They are attacked by hydrofluoric, con-centrated sulphuric or hydrochlorrc, and hot phosphoric acids


AlkalisHot solutions of weak alkalis, and cold solutions of strong alkaliswill attack glass, causing deterioration and disintegration.

GenerulHighly resistant to all chemicals in common use.

Ellect of Organic SolventsGlass fibre is not attacked by organic solvents, but the size onthe yarn may be attacked.

Insects

Not attacked.

€ . 0

7 . O

6 ' O

g

2 . O

1 . O

0o 1 0 2 0 3 0 4 0 5 0SIRAIN (% ELoNGATIoN)

L i t - _ - t . I l,- tI

r iI

661

r l


l\licro-organisnrs

Not attacked.

l.lkclrical l,ropcrtics-fhe

following values wcre obtained front measurcnlcnlsg l a s s :

'E' GlassUp ro 2,800

6.4J

6 . 1 I

0.0042

0.0060Volume resistivity - solid glass (ohrns/c.c.)

,c,ou bulk

G lossDielectric strengrh (volrs / nril)Dielectric constant (22'C.)

1O'� cyclesl0a cyclesl0ro cycles

Power factor (22"C.)l0! cyclcsl0r cyclesl0ro cyc les

22.C.'1 15" C.788.C.871'C.982"C.

r093.c.r260"c.

Coeltcictt of Friclion

With glass: 1.0 for clean glass.

2-5 x l0r rl 0 ?10"105t0'lt0 r10,

7 . t 46.'t9

0.m90.0t1

Oplical PropcrticsIndex of refraction (at 550 millimicrons; 0"C.):r .541) .Clarity: transparent,Ultra-violet transnission: opaquc.

Acoustical Propedics

Velocity of sound: 5,786.4 nVsec (18,000 ft lsec)Acoustic impedance (g.7cmx/scc.): l.4x 100Velocity of crack propagation: 1,603.25 m/sec (5,2(,0 ft/scc)

1.549 ('C' Type;


CI,ASS FIBRE IN USE

Gencral Characterislics

Plrysical Propcrties

Glass is a heavy fibre, with a specific gravity of the order olaluminium. It has good transparency,

The moisture absorbency of glass is negligible, and the fibreshows no swelling or shrinkage. This is a useful characteristic inapplications where dimensional stability in the presence of wateris desirable, and in electrical applications. It is detrimental inapparel applications, however, where absorption of moisture isa useful attribute.

Water affects the tensilc properties of glass fibre, bringing abouta reduction in tenacity after a very short time. This is due to theleaching out of some of the solublc materials from the glass,including alkali silicates. 'E glass, with its low alkali content, isbetter than'C'glass in this respect.

The high coemcient of ftiction of glass against glass, taken inconjunction with the high l lexibil i ty of l ine glass fi laments, makcsfor poor abrasion resistance. The movement of filament againstfilament during use brings about fracture of the filaments, andthe creation of a hairy fabric. The use of suitable lubricants andfinishes minimizes the efiects: metal coatings, for example, maybe applied to glass fibres to reduce surface friction.

Mechanical Properties

Glass fibre has the highest strength-to-weight ratio of any fibre,and one of the lowest elongations. These characteristics are usefulin applications requiring high dimensional stability, such as theuse of glass fibre as reinforcement in plastics. The low elongationis not a useful attribute in apparel fabrics, however, whereresiliency is an important factor.

Glass exhibits almost perfect elasticity, returning instantly andcompletely to its original dimensions on release from strain. Thiselasticity is exhibited over a very small range, as indicated bythe low elongation of the fibre.

Tlternul Properties

Glass has an excellent resistance to the effects of heat over a widetemperature range. Fabrics show an increase in strength up to

662

- - l'''1, l', -, -JJJB : S Y N T T I E T T C F I B R E S

about 205"C., after which the strcngth and flcxibility bcgin lofall. At 370"C., glass filaments retain 50 per cent of thcir originalstrength; at 538"C. they retain about 25 per ccnt. Thc c[Icct o[tempcrature on glass depends greatly upon thc composition o[lhe glass.

Glass is completely non-flammable, and this is one o[ the mostimportant factors in its textile applications. Glass fabrics are uscdwhere resistance to the spread of flame is of overriding irnpor-tance.

The hieh heat conductivity of glass is a useful attributcin electrical insulation applications, where close-wovcn glassfabrics dissipate heat rapidly. Despite this high hcat conduclivity,however, glass fibre finds an important outlet as heat insulationmaterial. In this case, it is used in the form of mats and waddings,where insulation is provided by the entrapped air.

Elearical PropertiesGlass is an excellent electrical insulator, and glass fibre findsimportant outlcts in thc clcctrical ficld. 'E' glass is dcsigncdspecially for this application.

Chertical and Biological PropertiesGlass has a high resistance to most chemicals. It is, howevcr,attacked by alkalis, which disintegrate it. Glass fibres may alsobe attacked by some strong mineral acids and by phosphoric acid.

The resistance of glass to biological degradation is complctc.

Washing

Glass fabrics wash easily, but they should be subjectcd to aminimum of mechanical action. They are best hand-wnshcd,without rubbing, squeezing or drying. Mechanical washing maybe carried out carefully.

Drying

Glass fabrics are best drip dried. They should not bc tumblc dricd.

IronlDS

In general, ironing of glass fibre fabrics is unnecessary. Ironingmay be carried out, however, using a'cotton'setting,

663

lil ir lI

H A N D A O O K O F T E X T I L E F I B R E S

Dry Clcaning

Glass fabrics may be dry cleaned, but great care must be takc[to avoid mechanical action.

End.Uses

InsulationGlass fibres are widely used for electrical, thermal ancl acousticalinsulation purposes. They are less bulky and more efficient inmany respects ttlan other insulators.

In electrical insulation, glass fibre offers a combination of hishsl.renglh, non-flammability, excellent corrosion resistance, goocldielectric strength, high heat conductivity and excellent moiitureresistance. End-uses include rotating equipment, transformers,switchgear, wire and cable insulation, and other applications ofthis type.

For thermal insulation, glass fibre is used in the form of matsand waddings, where the high heat conductivity of the glass itse.lfis a Irctor,of minor importance compared with'the insuiation pro-vided by the trapped air. Glass wool is usctl, for examplc, in theinsulation of houses, and for lagging hot water and stJam pipes.

Reinlorcentent in PlasticsThe_ use of glass fibre as reinforcement in plastics has becomethe largest single end-use for textile-type fibres. Glass fibres rein-force plastics in the same way as steel reinforces concrete. Thehigh strength of the nbres, coupled with their resistance to stretch,ensu-re a product of great impact strength and high dimensionalstabiltty. Tbe non-flammability of the fibres, and their resistanceto corrosioJr and biological attack, have added to their efficiencyin this application.

. Glass-fibre-reinfor,ced plastics are used in building boat hulls,rn car bodies, aircraft, radio and television cabinets, iot air ducts,flexible tubing, petrol (gasoline) storage tanks, UuitOing panetiin!,rranslucent sheet. lurnilure and innumerable other end_uses wherehigh strength, durability, light weight and resistance to deteriora-tlon are lmportant factors.

Industrial F iltrqtiottGlass fibre and fabrics are used for filtering gases and liquids inmany industrial operations.

- l l t l t t r t lI I L T I

665

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l lI

l lI

D : S Y N T I T E T I C F I D R E S

I'yrc ConlsGlass yarns uscd as reinforccnrent in rrdial ply tyrcs rcsult inbcttcr miles-pcr-gallon, grcater tread life, inrprovcd corncring andcoolcr running than tyres reinforced with othcr typcs of yarn.'l 'his is a major rnarket for glass fibres, especially irr thc U.S.A.

Belt itrgGIass fibre is uscd as reinforccment in industrial belting, includingconveyor belts for handling hot matcrials rnd driving bclts,particularly toothed timing bclts for car engirtes and irtdustrialmachinery.7'extilesGlass libres have nruch to recommend them as tcxtilc fibrcs. 1'hcyare strong and stablc to moisture, heat and other inllucnccs; thcyare not easily soiled or stained, and ihcy can be cleancd rcadilyin soap and watcr; thcy are non-flammablc, llut thc dclicicncicsof glass as an apparcl textile fibre greatly outwcigh its advantages,rnd therc is little prospcct at thc prcscnt lintc o[ glass fibrcbecorning a really inrportant fibrc for gcncral tcxtilc usc.

Class fabrics have a poor resistance to abrasion, the filamcntsbreaking as they rub against each other during use. Glass fibrcshave only a very small clongation, and do not have the'give'that is so desirablc a characteristic of a textilc fibre. Thcy do notabsorb moisture, and thc fabrics are uncomfortablc against thcskin. They cannot be dyed by normal tcchniqucs.

Despite lhesc drawbacks to thc usc of glass fibrcs for gcncrlltextile applications, the fibrcs havc established important cnd-uscs.'fhey

are made into fircproof fabrics for curtains and drapcricsin cinemas, theatres and othcr public buildings, and thc newcrtypes of fibre (e.g. Beta fibre) are now being used increasingly indomestic applications of this type. Tablecloths made from glassfibre, Ior examplc, are not damaged by cigarettes lcft burning onthem.

Glass fibres are used for apparel fabrics in special applica-tions such as car racins suits and suits for astronauts.

L I: r, - I: li - - |: - - il - !: l.,,: - !"i -J."r i Ii t It '


ALUMINIUM SILICATE FIBRES

Fibres spun from aluminium silicate, with or without the additionof minor amounts of other materials:

INTRODUCTION

A I 203.SiO2

Glass, asbestos and mineral wool fibres provide excellent servicein specialized applications for fibres up to temp€ratures of about540'C. At higher temperatures, they tend to become .ineffective.and there is a need for special-purpose fibres which can withstandtemperatures aboye this level. A number of ceramic-type materialshave been spun into fibres for this purpose, among themaluminium silicate.

Aluminium sil icate fibres were developed originally for use jniet.engines. providing a high-temperal.ure-resista;t (540-1,260.C.),l ight-weight, strong, f ibrous material of Iow lhcrmal conductivity.These fibres have since become of great value in manv apolica_tions outside the jet engine field, including high temperaturefilters, packings, gaskets, insulation (thermal,

-electriial and

acoustical) and the like.

-.Tbe manufacturing pr<ress for producing aluminium sil icatefibres is relatively sinrple, and the raw materials - alumina andsil ica - are cheap and readily available. These fibres can beproduced at lower cost than other lypcs of high-temperature.resisting fibres, such as the silica fibres.

TYPES OF ALUMINIUM SILICATE FIBRE

Aluminium sil icate fibres are produced typically as short staplehbre. or as long staple, lexti le grade fibrcs. The lonp staole tvoeis produced as finc or mediurn fibres to meet partic-ular iecuiie_menls .

Short staple libres are made from an aluminium oxide_silicamelt which contains small amounts of soditrm and boron (sodiumDora te) to he lp in cont ro l l ing the mel t . S tap le lens th i s 6 .35_z) .4 mm ( ' /a - l in ) ; f ib re d iameter 0 .5_10p.

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Long slaplc fbrcs o[ controlled diamctcrs arc produccd frontan aluminium oxide-silica melt which contains a small propor-tion of zirconia. Staple length 12.1-254 mnr (|4-10 in); fibrcdiarneters: fine, l-8 (mean 5) 1-r; ntedium coarse, 3-25 (nrcanl 0 ) u

FORMS AVAILABLE

Aluminium silicate fibre is available in a number o[ forms,including short staple bulk fibre; paper; long staple bulk; bothshort and long staple blanket; rope; yarn; roving; tape; coatingcement; chopped fibre; washed fibre; block; board; tubes; millcdfibre; felt; cloth; tubular shapes; cord; hollow braid; wicking;square braid; tamping mix; laminates: preforms; hydrautic scttingcompositions. Non-rigid forms are capable of being made intorigid or resilient forms by addition of a liquid, rcfractory hardcn-ing agent termed Rigidiscr.

NOMENCLATURE

Ceramic FibresAluminium silicate fibres are related chemically to the silicatemixtures that form the basis of ceramic (pottery) nratcrials, andthey are often included in a general classification callcd cuonicfibres. This is an imprecise and unsatisfactory tcrm which is,however, widely used.

Inorganic FibresAluminium silicate is an inorganic material, and fibres spun fromit are inorganic fbres.

High Temperature FibresThe growing importance of fibres capable of retaining uscfulproperties at elevated tempcratures has lcd to lhc usc of trgeneral descriptive lerm high tempersturc fbrcs. This tcrm iscommonly applied to fibres which can be used above about40O"C., and aluminium silicate fibres qualify for inclusion in thcgroup.


PRODUClION

Aluntiniunr Sil icate

A l: I mixture of alumina and sil ica, containing a small propor-tion of sodium borate (for short staple) or zirconia (for longstaple) is fused in an electric furnace.

Fibre Production

Molten aluminium sil icate is poured from the furnace in a smallslream. As it falls, the stream of l iquid mects a blast of com-pressed air or steam.

-fhe stream of aluminium silicate is disinte-

grated into fine droplets or particles, and these are attenuatedinto fine libres as they are blown through the air. The fibres arecollected on a mesh screen, forming a mat of llbre which iscoilected for processing.

STITUCI'URI] AND PITOPERI'IL:S

!'ine Strucaure and Appearance

Molecular StuclureAluminium silicate fibres are amorphous in structure, sinrilar inthis respect to glass. If they ale held at ten]peratures above1,000'C. and below the melting point for long periods of time,the meterial undergoes devitril ication; the amorphous materialacquircs an ordered crystalline pattern. This change makes thefibre more brittle, lower in tensile strength and more easilyabraded. There is also some evidence of shrinkase.

Fibre ForntAluminium silicate fibres are white. Thev are smooth-surfacedand of round cross-section.

Tcnsilc StrcnglhLong sraple. f ine: 12.600 kg/cm? ( I S0,000 tb/ in2)

medium coarse: 8.106 ke/cmr ( I 15.800 lb / in2)coarse: 3,500 k! /crn2 (50,000 th/ in2y ' (esr .y

668

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Spccil ic Grnrity

2 ;13 .

Thcrmal Propcrties

Mching point: above 1,760'C.

l+4 axi trttun U se 7' ct,tparaturc'. about 1,260'C.Aluminiunr silicate fibre shows no tendency to mclt or sintcrcven at temperatures up to 1,370'C., but there is a gradual changcfrom the amorphous glassy structure to the crystallinc slructurcat temperatures above 1,000'C., the change procecding frslcr athigher temperatures.

Specific Heat: Bulk fibre, measured at 60"C., pcr nSfivldesignation C-351 : 0.20.

Thernnl Conductivity: Ihe diagranr on pagc 670 shows curvcsof tlrcrnrrl conductivily flgainsl nlcln tcnlpcrntrtrcs for foltrfabricatcd fornrs.

Chemical Properaics

AcidsGood resistancc to most conrmon acids undcr nornrll conclitions.but attacked by hydrolluoric acid and phosphoric acid.

AlkalisCood resistance to dilute alkalis at normal tcmDcraturc. butattacked by strong alkalis.

MetalsThe fibres exhibit non-wetting charactcristics to nroltc|laluminium, zinc, etc.; they are frequently uscd for the conlain-ment of these molten mctals.

GcneralGood gencral resistance to most common chcnricals. Rcsisls bothoxidizing and rcducing atmospheres. No significant changc oncxposurc to hydrogen at 1,300'C.

669

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H A N D E O O K O F T [ , X T I L E F I B R E S

+ 3

..

F

zo

I

\COATINGCEMENTl2Olb/cu.1t.

BULK FIBRE

/\TAMPINGMIX

,z-BLANKING6lb/cu.1t .

,/ 4

--BLOCK-Ft3

/ZSOARDZ\PAPER

4MEAN TEMPERATURE. OF

Alttttritriurrr silicqte Fibrc; Thernul Conductivill'. This graph shows thethermal conductiyity of diflerent forms of aluminium silicate fibre('Fiberfrax') plotted against temperature.

lifrcct of Organic Solvents

The fibres are wetted by organic solvents, but resist attack bynost of them.

ALUMINIUM SILICATE FIBRES IN USE

Gcneral CharacaeristicsAluminium silicate fibres are used largely for insulation purposes,filling a gap that exists from about 400'C., where glass, mineral

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B : S Y N T I I E T I C F I B R E S

wool and asbestos arc often inadequalc, to about 1,260'C. Itcan be used for short exposurcs at higher lcmpcraturcs, but thcrcis some loss of resilience and some shrinkage. -l 'hc dcvitrificationwhich takes place al these temperatures does not, howcvcr, allectthe insulaling propertics of thc Ilbrc.

Extremely low thermal conductivity is one of the outstandingfeatures of aluminium silicate fibres, valucs ranging froln lcssthan + to 3 B.T.U.lhr./sq.ft. /

"F. /inch of thickness, depcnrling

upon temperatures and the form of the matcrial.Aluminium silicate provides a lightwcight, high tcmpcraturc

heat barrier with excellent thermal shock rcsistance, flamc rcsis-tance, resilience, chemical stability and clcctricitl propcrtics.'fhe fibres of aluminium silicate interlock. Thcre is no brittlcstructure to develop stresses during suddcn heating or chilling.

End UseE

Alunrinium silicatc libtcs are uscd for a varicty of high tcnrpcrl-ture applications, including thermal, acoustical and clectricalinsulation, filters, packings and gaskcts, contrinrrrcnt and con-veyance of molten / non-ferrous metals.

Bulk.

One of the major uses in bulk fornt is in high tcmpcraturcinsulation. End-uscs include furnacc hot-topping, hcatingelement cushions and jet engine blankcts. ' l 'hc bulk fibrc is alsoused as an expansion-joint packing in kilns and furnaccs loreduce heat losses and help maintain uniform furnacc tcmpcra-tures.

Brazing Furnaces, Short staple fibre is used in place of asbesiosin continuous brazing furnaces to cushion aluminium and coppcrparts.

Furnace Rolls. Many of the insulation applications for whichbulk fibre is used also require that thc insulation should bcvibration resistant, i.e. fibres must not be shaken loosc duringservice. Long staple fibres provide better vibration resistanccthan short staple; this is an importnnt factor, for example, whcnbulk fibres are used for irsulating rolls that convey steel and alloysheet mctal through annealing furnaces.

tI l A N D I I O O K O F T E X T I L E F I A R E S

Ggt Filtcrs. Long slaplc aluntinium sil icatc fibrc is uscd [orfi l tration of hot gases io thc region of 760"C.

Balls

il[ rr" fornred by bulking the fibre into a blanket-l ike shape,which is held together mechanically by wire or a similar fasteningdevice.

Air Conveyors, When exlremely hot materials are being con-veyed, the Rbre in batt form is placed jn the bottom of an airchanrber. Hot solids from roasting or calcining operations arefed into the upper part of the chamber, and air passing throughthe fibrous batt keeps the solids suspended for transfer to otherprocessing areas. The air nray atso serve to cool the solids. Thefibre balt is suitable for such uses because of its high temperatureresistance, its air permeabil ity, and the fact that it does notdeleriorate rvlren hot suspended solids are deposited on the battdufing shutdown.

Engirrc SilertcTs. The good acoustical absorption characteristicsof aluminium sil icate fibres, coupled with rcsistance to hightcmperatures and vibration, makes them suil.able materjal foracoustical insulation for jet engines.

Paper

Aluminiunr sil icate paper is made in a range of thicklesses, e.g.20,40 and 80 mils. Applications for paper include high tempera-ture linings, filters, gaskets, fabrication aids and electricalapplications.

Higlt Tentperature Lirings. The thin gauge and low thermalconductivity of aluminium sil icate papers make them useful lorhigh temperature l iuing materials. Many non-ferrous metals, suchas aluminium, magnesium, and some brasses and bronzes do notreadily wet or attack the fibrc. Paper nrade from.it may thereforebe used to l ine metal ducts, ladles, crucibles, spouts, laundersystems, ingot nroulds and other metal components used to handlethese molten metals.

Aluminiurn sil icate paper is also used as a l ining for combustion

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613

t r t l t\ \ l

B : S Y N T I I E T I C F I I N T , S

ch;rrrrbcrs in oil-f ircd tionrcstic hcirt ing unils. ' lhc

flpcr prolcclstlrc slccl wall of thc chambcr fronr dircct f lanrc inrpingcnrcnl.

Goskets. 'fhe papcr is uscd for grskcts on pressurc vcsscls,

flanges, orif ice blocks and othcr cquipmcnt lhirt encountcr highternperatures and make use of nrodcraicly low prcssurcs. Sccauscof the rclatively high porosity of thc paper, it can be inrprcgnatcdwith sil iconcs, f luorocarbons and sirnilrr hcat-rcsislant inrprcg-nants to adapt thc papcr to highcr prcssurc g skct ap;.rl ications.

Processirtg l irLr. Aluminium sil icate papcr can also bc uscdas process and firbrication aids. lt is usctl succcssfully, forexample, as a braking cushion in nraking brazed stainlcss stcclhoneyconrb sandwich structurcs. Dimensional stabil ity and incrt-ness arc pnmary rcqulrcments.

Blocks or Boards

Pr.clornrcd blocks arc nradc of short slaplc fibrcs arrrl srrit lblcl i l l c rs and b inders wh ich do no t rcduce thc 1 ,260"C. r r rax i r r ru r r rservice temperature o[ the matcrial. Aluminium sil icalc blocksor boards rcduce hot wall tenrperatures in industrial f irrnaccs,kilns aud combustion chambcrs.

'Ihe block providcs lowcr hcrt

losscs and lightcr walls as compared rvith nrany convcntionalrcfraclory fire bricks.

Devitri l ication nrly take placc in conrbustion applicutions,owing to the high lcrnperalurcs involvcd.'fhc tcnrpcralurc grarlicntthrotlgh lhe block is srrch, howcvcr, that dcvitri l ication is gcncrallyconfined to the hot face of the block. The block oltcn appcarsto be stronger after exposure to dcvitrifying conditions thunbefore. Exposure to high hcat conditions does not appcar to havca serious eflect on lhc insulating propcrties of thc blocks. andsuch blocks may be re-used, even though the hot faccs nrry bcmore easily abraded and show somc surfacc shrinkage.

Oil-Jired Furnaccs. Illocks or boards line thc corrrbustioncharnbers of oil-f ired furnaccs. Thc usr.: of alunriniunr sil icatcblocks reduccs slag build-up on thc chanrbcr wall, and l itt lc ifany corrosion from direct l lamc impingcnrcnt occurs.

' l 'hc l ight-

rvcight block also elinrinatcs thc necd for a forccd air 'tf lcr purtlc'of the furnace. Purging is norv done entirely by blccd-dorvn of

ll

t.n n n F,E.F nn n F, n n n nh EH A N D B O O K O F T E X T I L E F I B R E S

lhe prinrary air prcssure chanrber and by natural draught throughthe secondary air control damper and blower.

Tunnel Kilns. The good resistance of aluminium silicate blocksto thermal shock is of particular advantage when the blocks areused as roof tiles in tunnel kilns. Tunnel kiln operations occa-sionally involve jam-ups because of movement of skidrails orwar€-supporting setter plates. Substantial production time maybe lost in waiting for the kiln to cool slowly in order to avojdfracture or spalling of the insulating brick. Kilns insulated withaluminium silicate block can be cooled more rapidly because ofthe matcrial's superior resistance to thermal shock. Also. theblock may be re-used after the tunnel has been dismantled andthe jam-up straightened out.

Electric Furnaces. Aluminium silicate blocks are used forlining electric furnaces used to form graphite tubes, The blocksproyide eflective insulation while maintaining a furnace tempera_ture of 900'C. for several days. The blocks have proved satisfac-tory over several years of operation, without deterioratios ineither oxidizing or reducing atmospheres or atter contact

-witb

pitch vapours and sulphur gases.

Tex.tiles

Several types of alumirrium sil icate texti le products are available,made from long staple fibres. These include blankets, roving, yarn,rope, lape and broad woven textile goods. yarns reinforced withglass filaments, alloy wire and other materials are also made.

Blat*ets. Aluminium silicate fibre blankets are used as hichtemperature insulation in furnace tops, sidewalls and ducts;turbine exhaust l ines, and superheated piping. In piping applica_tions, the bla-nket is particutarly welt suited

-for insuiating

tabflcated section such as flange and valve covers and elbows.These_ insulatiorrs are usually assembled by encasing the blanketln a flexrblc alloy screen or heat-resislant cloth and stitching thea-ssembly together. Removable coverings may be made u! inthis way.

. The degree of insulation obtaiDable witb these blankets isindicated by an installation in an incinerator used to burn exhaust

674 675

f}B : S Y N T H E T I C F I B R E S

fumes generated in a paint spray operation. The blankct rcduccda combuslion chamber temperature of about 900"C. to a srfclevel of about 65'C. on the outsidc shell.

Aluminium silicate blankets are also used as a packing betwccnfirebrick linings of a petroleum refining furnace. fhe'lircbrlctexpands and contracts with lluctuating temperal.ures in thcfurnace, and the blanket acts as an expa-nsion joint fillcr as wciias a seal against gas leakage.

Combinations of aluminium silicate blankets and glass fibres orasbestos materials offer interesting possibilities. Tf,e blankct isused 10 reduce the temperature: to a safe range for thc glass orasoesros. A flange cover used for supcrheatcd slcam DiDiucreduced a hot face tempcrature of 600.i. to about S0.C. on iiricold^face through 63.5 mm (2tA in) o[ aluminiunr silicatc birrrietand J6_.t mm ( I )4 in) of Blass fibre blanket. The assernbly is aboutone,hal , the weight of convent ional insulat ion.

Othcr Taxtilcs. A variety of applications for othcr tcxlilcprooucts rnclude gaskcts and scals itr hcat-lrc ting furuaccs. roncpackiugs for moulds (bctwcen lhc hot top ,rn,f r-n" l,rg"i-niourulin steel . manufacture, bag filters for coliecting not c-arbon anjcnemlcats, and electrical wire winding and wrapping.

Castables

Castable aluminium silicate fibre conrposilions arc availablc,which incorporate high lemperalure binding nratcriats. Alu.mrnru.nr s lcate ollers extremely good tbcrmal shock rcsistancc,Iow--thermal conductivity an4 much lower density than prcviouslvavailable castable refractories. In addition to'drving' lirls-anjpressure vessel linings, castable aluminium silicats hbrc has becnused on b-oiler access doors, and as incinerator linlngs, Ouci insu_latron and induction furnace shielding,

Drying Lids. Castable aluminium silicate is used in lids fordrying _and settling ceramic linings in casting pots. Thc lid- is9x-p-9s99 to a temperature cyclc of room tcmperature to more than1,093"C. Burner blocks are mountcd on thc lid, and "n nir_o"imixture is burned to provide a heat sourcc. ln operation. ihccastable surface is suspended over the casting pot and thus is indirect contact with the flame sweep during nring. Lias madc froin


other types of castable refractories weigh 675-900 kg (1,500-2,000 lb). For an equivalent thickness, thc aluntiniurn silicate lidweighs only 257.5 kg (350 lb).

Pressurc Vessels. Castable aluminium silicate compositions areused as linings for pressure vessels. The lining is installed on theinner wall of the vessel, conforming to the contours of the topand bottom, as well as the inlet and outlet ports. In one applica-tion, the vessel is designed to withstand 2l kglcnt2 (300 lb/in2)gas pressure at 815"C. The l in ing. appl ied 5 l mur (2 iu) th ick.permits the original 5l mm (2 in)-thick stainless steel wall to bereplaced with a l3 mm (% in) carbon steel wall.

Moulded Shapes

Rigid, structural moulded shapes of aluminium si[cate libres andhigh temperaturc binders are used for many applications. Theseinclude re-usable risers for non-ferrous casting, which have theadvantage that the riser is not wetted by molten aluminium ormagnesirrm. Other applications are combustion chambcr liners,baftles and flame detectors, small furnace and oven liners, and cansctter plates and shields. Corrugated sbeeting serves as spacers inhigh temperature absolute filters and may be adaptable to base-plates for heating element wires.

Itrtprcgnated Moulclings. Rigid :noulded products nrade fromaluminium silicate fibre, because of their relatively high porosity,may be impregnated by vacuum and immersion techniques withcommonly available binders, including irorganic binders, rubber,phenolic, epoxy and silicone solvent or latex-base materials.

Other Applicatiotts

Aluminium silicate fibres are being used commercially and ex-perinrentally in a great number of applications which show parti-cular promise for the future.

Snog Control. Incineration of waste material at temperaturcslrigher thau those commonly employed can reduce contaminationof the atmosphere. Burned at 760'C., raw scwage produces noobjcctionable odours or air pollution. Aluminium silicate fibre

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insulation nrry bc uscd cllcctivcly in thc rlcsign of pllnts forburning waste at thcsc incrcascd rcmDcraturcs.

Filtrution ol Rudioactit,c particy'c.r. Alunriniunr silicatc fibrc isused in li ltering radioactivc particles from hot gas strcanrs ina lomic energy p lants.

Missiles und Rockets.'fhe resistancc of lightwcight alunriniumsilicate libre to crosion and thermal shock is advantagcous innrissiie and rocket insulation.

Firc-resistant Products. The non-flanrmability o[ alunriniuntsilicate^ fi bre_ is_ a useful property in the manutaciure of fireproofsrfes, files, desks, panels and partitions and thc likc.

677

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f [ - l - - F I -H A N D B O O K O F T E X T I L E F I B R E S

I\{E TALLIC FIBRES

Fibres produced from metals, which may be alone or in conjunc-tion rvith other substances.

INTRODUCTION

Filam€nts of mctal haye been used as decorative yarns since thevery earliesl t inres. Nletal threads, for example, were used by thePersians for producing the intricate and attractive patterns intheir carpets; the ancient Egyptians woye threads of gold intothe fabrics of their ceremonial robes.

These metal filaments were made by beating soft metals andalloys, such as gold, silver, copper and bronze, into thin sheets,and tben cutting the sheets into narrow ribbonJike filaments. Thefilaments were used entirely for decorative purposes, providing aglitter and sparkle that could not be achieved by other means.

As textile fibres, these metal filaments had inherent short-comings which restricted their use. They were expensive to pro-duce; they tended to be inflexible and stiff, and the ribbon-likecross-section provided cutting edges tlrat made for a harsh, roughhandle; they were troublesome to knit or weave, and they hadonly a l imited resistance to abrasion. Apart from gold, the metalswould tend to tarnish, the sparkle being dimmed with the passageof time.

Despite these shortcomings, the metallic ribbon-lilament hasremained in use for decorative purposes right up to the presentday. The development of modern techniques of surface-protectionhas brought cheaper metals into use; aluminium foil, for example,may be anodized and dyed before being slit into filaments whichare colourful and corrosion-resistanr.

Ribbon-filaments are now manufactured in considerable ouan-lity, e.g. as tinsel. but they remain an essentially decorativematerial. The filaments are weak and inextensible. and are easilvbroken during wear: they lack the flexibil i ty that is essential in agenuine textile fibre.

Mullicomponent Metallic Filanlents

In recent years, the ribbon filament of metal has undergone a

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B : S Y N T H E T I C F I A R E S

transformation which has changcd thc comnrcrcial ouflook forthis ancient product. The metal of the l i lamcnt is now sonj*i.t i".tbetween layers of plastic, which protect it from the ;t;;;il;;;and from other corrosive influences.

The multicomponcnt fi laments produccd by slitt ing srndwiclrmaterials of this type are strong-r and moie,obusi ih;; i;;f i lamcnts cut from metal foil alone. They retain tt" giitt., oithe mctal during prolonged pcriods of use, onO trauJ a iof1,pleasant handle. Coloured pigmenls may be addcd to the ad-hesrve_used in sticking the plastic f i lms to the mctal foil or mctal_Itzed fi lm-

. Mctall ic f ibres of this type are now widely used in the tcxli lcIndustry, and are produced in a range of colours anrl forms bvmany manufacturers. They remain, however, esscntiallv dcco#Itve materiats, and their applications are rcstrictcd to this typc ofuse.

Single-componcnt Mctallic FibrcsWith the rapid dcvclopment of the nrissilc and spacc_vchicle, thcsingle-componcnt rnctall ic f ibre has assumccl n n"* i-poriin"".Metals are being made into fi laments so l ine that tht;; i";;;degree -of flexibility which enables them to scrve i. pi""ti."itexli le f ibres. These fine-fi lament mclall ic f ibrcs may Uc,p,,,r nn.iwoven and knittcd on normal texti le mrchincry, ind rhev havcphysical and chemical characteristics rhat ."nOii rt.- oi oi"niimportance in many tcxti le applications.

Many tynes of nretall ic f i lantcnt arc now bcing proclucc<Iconrnrcrcially; sorne, l ike stainlcss sleel, are nraking go-od progr"r,in a variety of tcxti le end-uses.

TYPES OF METALLIC FIBRE

Metallic fibres used in the modern tcxtile industry are of twomain types:

(l) I4.etallic (Singlc-component) Fibrcs, or Mctallic (S.C.)Fibres.

(2) J\4etallic (Mulri-component) Fibres, or Mcrallic (M.C.)Fibres.

In. the section which follows, the two typcs of mctallic fibrc arcconsidered separately under these heartings.

:I J A N D B O O K O F T E X T I L E F I B I I E S

NOi\,I I ]NCLATURF,

Thc tcrnr nrctdlic l ihrc, in its general sense, nlcans sinrply a l iblc

that is nrade fronr metal. Fibres of this typc also comc into thc

catcgory of inorgunic {ibrcs.

Fedcral Trade Connissiotr Dclinitiott

The gcneric lcrm Drclallic was adopted by the U.S. Federal TrarleCommission for f ibres of this type, the ofl icial definit ion beingas follows:

Meiqll ic- A nranufactured fibre composed of metal, plastic-

coated mctal, metal-coatcd plastic, or a core completely coveredby metal.

(I) METALLIC (SINCLE.COMPONENT) FIBRES

INTR,ODUCTION

The ductility of metals makes possible their conversion into wire,by drarving the nretal tbrough dies that bccome successivelysmallcr. This process resembles, in some degree, the productionof a synthetic fibre such as nylon by extruding molten polymerthrough the orifice of a spinneret. In each case, the nraterial isbcing forced into a continuous length of narrow-diameter rod byforciug it through a hole of appropriate diameter.

The production of wirc is a traditional hurnan craft that hasits origins in the earliest days of the metal-working civilizations.As the technique of rvire-drawing became more relined, it becamepossible to produce wires of smaller and smaller diameter, butthe nature of the process set a limit on the fineness of the wirethat could be produced economically in this way.

Fine wire is, in eflect, a mononlament of metal, and it baslong been woven into fabric-like structures such as windowscreens, wire support structures in industry, filter screens, and thelike. The metal wires used for these applications, however, do nothave the flexibility that is a characteristic of a genuine textilefibre; they retain much of the inherent stiffness of the bulkmctal from which they are formed. They are quite rigid materials,and this rigidity imposes mechanical difficutties in the weaving or

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kn i t t ing opera t ions ; i t l im i ts hand l ing and prodr rc t ion r r l cs , i tndrcstricls lhc cnd-Lrse applicalions of rvovcrr wirc flbrics.

On lhc olhcr hand, mctals havc inhcrcnl chanlclcrisl ics lhirtcould bc of very great value in many modern tcxti le applicatiorrs;thcy could serve in cnd-uses for which organic, glasj antl othci'normal' texti le f ibres are inadccuale.

During the lrte 1950s. lhc devclopmcnt of high-spccd fl ighrand space travel created demands for f lcxiblc rlalcrials ihat worrldbe caprble of withstanding uniquc cnvironnrcntal con<.lit ions.These materials would be used, for cxamplc, in the manufaclurcof protectivc garments, antenna mcmbrancs, parnchulcs and othcrstructures used in thc space prograntme. It bccanre tpparcnt thatlhe requirements for such applications could bc mct bv thc nro_duclion of f ibres of adequatc flexibil i ty frorn h igh-tcirr pcrri u rcnretals or alloys, c.g. of the stainlcss stcel typc.

The flexibil i ty of mater.ials is a function of cross-sectional arcu.As thc diameter of a rod is rcduccd by onc-hal[, its f lcxibil i ty in_creases by a factor o[ four, The problcm of producing rrrcll lf ibrcs of adcquatc flcxibil i ty rcsolvcs i lscl[, thcicforc, ir ito thrtctl producing l i lancnts of thc lcccssury l incncss, ln thc casc ofa metal l ikc stainless steel, with a nrodulus of 29.000.000. it isnccessary to reduce the diameter of a rod to form a fi l tnrcnt ofapproxinralely one-half-thousandlh of an inch (lZ nricrons. rD_prox.)^to attain a flexibil i ty equivalcnt to that of r -t..] t l tcxnyron nnnent .

l)uring the 1960s, methods of producing mctal l i lanlcnls oI thcrcquired fineness werc dcvelopcd. lnit ially, thc proccss wirs soexpcnsive that thc l i lanrents were rcstrictcd in thciiusc to csscntiI lnri l i tary.a_nd aerospace applications, rvherc low volunrc and highcost could bc lolcralcd. Subsequcntly, dcvelopnlcnt o[ thc procc-sshas lcd lo increased prodtrction n(l a sUbstanli l l lowciinc otcosts. Ivlctal f ibres havc bccornc availablc in qrr:rntit ics antl i l acost which entit les them to considcration as gcnuinc texti le f ibrcs.

TYPES OF METAI-LIC (S.C.) FII}t{E

Continuous filamcnt yarns and staple fibre are produccd frtrnta nunrber of difier.cnt metals and alloys, thc st:rinlcss stccls 0(X)series l8/8 alloys) bcing particularly imporlant. Nickct trlscsupcr alloys, such as Chronrcl R and Karnra, and scvcnrl of tlrr:

! - E n n f : r r t l - r : r :l ,


refractory metals such as niobium and tantalum have also been

formed into fi laments of 12 microns and finer.These metal fibres are available as twisted multifilament yarns,

tow and staple fibre.Multinlament yarns are heat-set and without torque. They.are

tvoicallv of 90 .na t OO, I Z micron diameter fi laments, equivalent

At ix t iO- l3O (den 100-300) approx . ; 25 tn ic ron d iameter

filament yarns are also available for industrial applications such as

high temperature conveyor belting or cordage, where iigh tensile

strength is particularly important. Filaments of 8 p diameter and

finer are available.Core-spun and wrapped yarns may be made with organic and

glass fibres, the metal being either core or wrap.Filament yarns may be bulked by the conventional processes to

provide an unusually elastic textured yarn which lends high cover

to fabrics.Staple fibre is available usually in the form of sliver.

PRODUCTION

Metallic (S.C.) filaments are produced by drawing either singlelilaments or mullifi lament strands.

Single filament drawing prodtrces excellent quality metallic-ftbres, but multifilament drawing offers the best possibility ofreducing cost and increasing availability. One method of drawiogmultifiliment yarns is to enclose a bundle of 2 mil. (0.002 inch)wire in a sheath of a dissim.ilar alloy.The sheathed bundle is drawnto the required extent, and the sheath is removed with nitric acidto leave ihe multifilament yarn ready for sizing, warping andweavlng,

PROCESSING

Staple Fibrc

Staple fibre may be produced from continuous filament tow byprocessing through tlre Perlok System for fibre breaking. Tensioncontrol, special guides, especially-hardened breaker bars' etc., arerequired, but the process is essentially the same as that used forbreaking organic filameot tow.

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The sliver formed in this way of 9.8-15.2 cm (4-6 in) staplc,may then be processed by conventional gill ing techniqucs (c.9.Warner-Swasey pin-drafter)' Slivers as light as 16.7 g/m ( I 5 g/yd)may be made with very few fibres in the cross'section.

Metal fibres may bc made more amenable to proccssing byroughening their surface to improve drag or drafting,charactcr-istic-s. Thii property is reflected in excellent fibre-to-fibre intcr-action during drawing, and high translation of fibre strength toyarn strength at appropriate twist multiplicrs.-

Roving 1nd spinning processes may be applicd- in a convcn'tional nianner ind yarns of 100 per ceni stainless stccl, forexample, have been spun successfully.

BlcndsThe primary application for stainless steel fibre has bccn inblencli with organic fibres l{any important cnd-uscs ,rcquircblends containing vcry snrall proportions of stainlcss stccl fibrcs'

On the American Worsted System' thc blcnd is gcncrallyachievcd at the pin-drafter' Sliver of stcel ' ibrc is introduccd tothe pin-dra{ter with an appropriate number of organic nbrc tops'Thrie or four passes through the pin'drafters achicvc-a-goodblend with as little as + per cent by wcight of stainless stccl lib-rc inthe Rnal yarn. Worsled yarns o[ 60s count and highcr' containing

?1 per c€nt steel, may be made in this way.When a low is bcing used, the blend may be startcd at thc

filament-breaking machine by introducing stainlcss stcel andorganic fibre low simultaneouslY.

Worsted-yarn blends containing small proportions of nrctrlfibre may also be made satisfactorily by introducing Jlood orTurbo-brlken metallic fibre sliver along with Pacilic Convcrtcdorganic fibre or top to the pin-drafters for gilling and blcnding'Ya-rns macle in this way are more applicable to linc worstedwoven fabrics than the tll-Turbo yarns described abovc, whichhave been used primarily in knitted structurcs.

Conventional opening, carding and spinning systems arc suit-able for processing metal fibre in blends with wool or man-madcfibres foi use in woollen spun carpet yarns. The various settingson the machines are determined by the predonrinant fibre in thcblend.

Metal fibre is fed to the card web after the first breaker section.

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The tow end is fed from an overhead or sicle_feed positioninto the centre of the card web before delivery to tfre cJnr"- oiside draw feed. Care should be taken to unwind tbe tow end iiomthc side o[ the package and not over the end of the Dackapc toprevelt unneccssary twisting. The metal fibrc should be a-ddedto the blend subsequent to peralta or burr crushing rolls.

The advantages of using this technique are as foll6ws;l. No alterations in machine settings or production outputs are

necessary to manufacture catpet yarns containing metal 6trc.

^.2. Uniform blending of the small percentages of the metalfi bre is obrained. Depending on the widih of thelard w"b. w"iJiperccntages of mctal fibre in the spun yarn will uary fr6mapproximately + to + per cent.

.3..The low percentage additions by weight of metal fibre areobtained by direct feed.

...,,4; 11.:-"9:.ru.ing blending techniques which are necessarywfln stapte libres are avoided.5. The additional advantage of significant reduction of in_process static in operations subsequent to the addition of metal

fibre is obtained.

_ Cottonlength stainless steel fibres may be made by roller-drawing a Hood-broken sliver on super

-long dratt "quipr*ni.

Blending of organic fibre and sleel nU.e ,nJv tt.n U. ilcom_plished by appropriate doublings.

Non-wovensStaple steel fitre may be processed into 100 per cent carded andgarnetted webs to form non-woven structrlres. It may also befed.to air-lay web-forming systems as sliver or card *"1 ro-iorrnunrrorm ttbre densll.y webs. These webs may be comoacted bvvarious nreans to form highly efficient, high "Lpu"ity nii", -.OL',vroratton lsolators. etc.

Dyeing

Stainless steel (304 type) fibre rnay be.dyed with certain com_inercial textile dyes to produce dark shadei.

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STI {UCTIJ I {E AND PI tOPERTI I :S

'l he properties of a metal ftbre arc esscntially thosc of thc metalitself. The general characteristics of metal librcs as they rclatc tolheir use in textilcs are discusscd in the next scction.

Details of the Structure and Propcrtics of stainlcss stccl fibrcsare given on page 690.

METALLIC (S.C.) FTBRES IN USE,

Gcncral CharactcristicsMetals have a number of general characteristics which can be ofgreat practjcal uslr in textile applications.

Meclrurical Propu|icsThe potential high yield and fracture strengths of most mctalsmake possible tlre production of fabrics which excced in strcngththose that can be produccd from cxisting organic or glass fibrcs,The molecular architecture of metals imposcs a cbaractcristicbehaviour under stress which diflers from that of a typical organictextile fibre. The stress-strain curve of a metal fibrc, for example,shows a completely elastic behaviour up to a yield point. It isdevoid of a viscous component such as we lind in orgnnic highpolymers, and which we identify as primary crecp; this enablcstextile structures to be made with design loads far in cxcess ofthosc achicvable with organic materials.

The absence of a signincant viscous behaviour charactcristic irrnretal fibrcs ensurcs dimcnsional stability in ccrlain struclurcswhich, at best, would be difficult to achicve with convcntionaltextile materials.

The most significant diflerence between organic fibres and nlclalfibres lies in the Yorng's lr4odulus of Elasticity, which is mostreadily recognized as the rigidity or stiflness of a material. Mostorganic textiles have a Young's Modulus of around 50(),0(D,wbereas most lnetals exceed 10,000,000, Stainless stccl. forexample, has a modulus of 29O00,000.

It was this high modulus of elasticity, and consequcnt stil lness,which previously excluded metals from usc as tcxtilc nrntcrials;it placed severe limitations on the proccssability and cnd-uses of

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in industrial applications such as drycr fclts in paper'nating'where the thcrlnal conductivity of thc blcndcd yarns contributesto drying efnciency.

Electrical Properties

Resistance Hearing. Metals. as a rule, are excellent electricalconductors. Within tbe range of high conductivity, howcver, thercis a broad spectrum which inclrrdcs metallic matcrials whose resis-tance to thi flow of electric current enablss them to bc used asresistance heating elements.

Elinination ol Stalic. The high electrical conductivity of mostmetal fibres provides an eflcctive mcthod of eliminating staticeiectric charges. Blencls containing low percantagcs of mctalfibre providJ fabrics that are essentially stalic'free. If a singlemetal fibre is incorporated in the cross'scction of a yarn, nnd i[the metal fibres along the yarn are within a critical distance fronreach other (without necessarily touching), suflicicnt clcctrical con-tinuity is provided to obviate the accumulation of high concen-trations of static electricity.

In such a structurc, the elimination of static chargcs nray bc o[much greater economic significance lhan at 0rst appcars. Apirrtfrom tLe nuisance created by clinging of garmcnts, static clcctri-citv encourages soiling of fabrics by atlracling particlcs of nir-borne dirt. And without ihc electric chrrgc to hold it to thc fibrc'such dirt as does accumulate on tlre fabric is casily removcd Thismeans reduced maintenance costs in applications such as carpcts'and ease-of-care propcrties in apparel fabrics.

In some environmints, the possibility of a spark arising froma static charge n.tay be a potcntial hazard. When inflammablefluids are bcing handled, e.g. in fuelling stations or holpitaloperating roomi, the danger of explosion may be matcrially re'duced if clothing is static-free.

The use of metal libres in static control provides an antistatictreatment that is permanent, and lasts the lite of thc garment'Wear, Iaundering ind dry cleaning, heat, light or comm-on chcmi'cals will not influence the retention or eflectivencss o[ thc clcc'trical conductivity of the yarns or fabrics. Furlhermore, by thcverv nature of this technique of static control' thc efiectivcnessof the treatment is completcly independent of thc moislurc contcnt

lH A N D B O O K O F T E X T I L E F I B R E S

the fibres. lt is only with the advent of modern ultra-line metalfibres that adcquete flexibility has been achieved.

Spccific GravityMost metals have a high density in comparison to those of or-ganic materials, and this can be a serious disadvantage in the useof metal fibres for many applications. Stainless steel, for example,has a specific gravity of 7.88, compared with nylon at 1.14 andpolypropylene at 0-9. lt is difficult, therefore, to use the denieror tex designations for fineness, or the cN/tex or g/den values fortenacity, without compensating for this wide difference in density.

The high theoretical strengths of some metals, however, willresult in high strength/weight ratios, as well as the high modulus-to-weight ratios now realized.

Chenical PropertiesThe resistance of metals to chemicals at room and elevated tem-peratures covers ranges which differ generally from those oforganic flbres. Metal fibres can be exploited, oo this account, inmany military and industrial end-uses where specific chemicalresistance is a requiremeut. There are, however, applications inwhich metals may sufler corrosion due to chemical action.

T lrcnnal PropertiesMany metals are able to tolerate and endure tempetatures higherthan those which organic fibres will generally withstand. Mostorganic fibres may be used in practice up to 120-260"C., whereasmetals can be expected to perform useful structural functionsin temperature ranges well in excess of 260"C. Metal textile fibrescan operate usefully, for example, at temperatures well over1,000'c.

Most metals are good conductors of heat, and metal fibresmay function as heat-sinks when used in adequate proportion inblends. Thus, metal fibres may protect organic fibres in the blendfrom the effects of elevated temperature, by conducting away heatbefore the temperature of the fabric is raised to a level wheredamage to the organic fibre may occur.

This property is of significance in applications such as protec-tive clothing, the metal fibre acting as a safeguard against theeffects of brief exposure to high temperatures. It is also useful

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o[ the fabric, its f inishes, or the environmert. The antistatic pro-pcrties rre retained even after fabrics are clried i lr an oven toconstant weight.

lvtost organic antistatic agents depend for their eflectivencsson the absorption of nloisture fiom the atmosphere, and theireflectiveness wil l comnronly be reduced as the relative humidityfalls. This is unfortunate, as under these conditions the accumula-tion of static is most evident.

Organic antistatic agents are often wax-like substauces in whichsoil nray become embedded, and they tend to act as soil-traps.Thc incorporation of metal f ibres as antistatic agents does not inany way contribute to soiling of the fabric.

Pilling. In structures composed of bulked, lofty yarns, theclimination of static reduces the tendency to pilliog. Static electri-city encourages the accumulation of l int, dander and fly, whichserve as nuclei around which unlike charged fibres aggregate onthe face of the fabric to form an incipient pill.

Magtrctic Properties. The magnetic properties of some metalsmake possible the development of novel textile applications.

Micro-wat,e Reflectivity. Fabrics made from blcnds containinqa low percentage of metal f ibre have a high micro-wave reflecli-vity. This makes possible the production of micro-wave reflectivegarments, reflective tow targets and other military applicationswhere radar reflectivity is important.

END.USF,s

Continuous filament metal yarns may be woven into a range of[abric constiuctions, including the plain weaves, twills and sitins.The1, rr1ut be knitted on both warp and weft knitting systems,and braided, flat and tubular; they may be used io filamentwound composite systents with various resin matrices.

Thc properties of these textile structures confirm the exDecta-tions of high temperature lolerance, high fiex-life, excellent abt.a-sion resistance, corrosion resistance and dimensional stability.The structures are, in fact, true textiles, manifesting drape'andhand as a textile technologist indges these characteristics.

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The labrication of nretal fibrc textilcs is achicvcd on convcn-iionaI textile processing equipntcnt at conrmcrcial productionrates, and without inordinate modifications. In sonrc instanccs,in order to achieve good running characteristics, spccial finishesare applicd to the yarns to improve internal filarncnl.-on-filamcntabrasion resistance and to add lubricity ro lhe yarn surfacc toreduce wear on guides, needles and other nraclrine surfaccs.Certain of thcsc finishcs, rvhcn lcft on thc filatitcnt, contriburc lothe end-use pcrformancc of the fabric by cnhan;ing wcar lifc,corrosion rcsistance, colouring and bonding to othcr nlatcrials.

Staple libre yarns spun from 100 per ccnt nrctrl fibrc, or lrornblends containing metal fibre in all proportions, nray bc knittcdor woven into a wide range of Iabrics.

Very short fibre, with aspcct ratios oI I to 100 to 1,000 arcused as reinforccment in resin, metal or ceramic mrtriccs, lcndingstructural, electrical, thermal and nragnctic propcrtics to the con)-posite structure.

CarpetsBlends of metal libre with carpct fibres providc c rpcts that arcessentially static-{ree. As little as * to + per ccnt o[ a stainlcsssteel fibre, for example, will reduce static to bclow thc levcl whicbis noticeable to an individual.

I nrlustrial A pplicatiorts

Metat fibres, such as stainless steel fibres, may be used in manyindustrial applications. They provide reinforccmcnt in nrcchanicalrubber goods, including tyres, high-temperaturc-lolcrtnt flcxiblcconveyor bclts, Fourdrinier wire and papcr nrachinc wct anddryer felts, filtration fabrics, both woven and non-wovcn, cordngc,braided hose and webbing where high flerlifc, corrosion rcsist-ance, dinrensional stability and strength are dcnranding perfor-nrance characteristics.

Raschcl knitted commercial fish netting and cargo handlingsystems also hold attractive prospects for ntetal fibre textilcs.Sewing threads are ntade efiectively from metal librcs.

Apparel Fabrics: Honte Furnishings, etc.Low percentage blends of metal Rbres with bulkcd acrylics, nylon,polyester and wool are made into knitted fabrics such as men's

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t r h h - h ffi:�B: SYNTHETTC FI DR ES

Tenacily

Standard: 22.1-28.3 cN/tex (2.5-3.2 g/den)\tl et: 22.1 -28.3 cN/tex (2.5-3.2 g/den)Std. loop: 15 9-21.2 cN/tex ( 1.8-2.4 g/den)Std. knot: 16.8-22.1cN/tex (1.9-2.5 g/den)

Tensile Strength

Annea led : 7 ,000 kg /cnr2 (100,q00 lb / in2)Yield strength: 3.500 kg/cpr;50000 lb/ inz

Hard : 1 7,500-26.950 kg/cmr (2^50,000-385,00p lb/in r )Yield strength: 15,400 kg/cmr;220,000 lb/ inz

Elongation (per cent)

Annealed : I IHard : 1 .5

[laslic RccoYcry (pct ccnt)

100 at I per cent; 66 at 1.5 per cent

Modulus of ElasdcityAnnealed: 2,030,000 kg/cm2 (29,000,000 lb/in2)


hose, ladies' swcatcrs, double-knit fabrics, woven worsted fabricsand specialized work clothing fabrics.

The incorporation of higher percentages of metal fibres in theseapplications makes possible the resistance heating of the mater-ials, e.g. in various items of clothing, and in home furnishingssuch as draperies, upholstery fabrics, bedding, etc. Static-freeand electrically heated transportation fabrics hold considerablepromise for an expanding market.

STAINLESS STEEL FIBRES

Fibres spun from stainless steel.

INTRODUCTION

Stainless steel was one of the first metallic (s.c.) fibres to bedeveloped commercially for textile applications. A number offirms have taken part in the development, and several stainlesssteel fibres are now available. The information which followsrelates primarily to a fibre of 304 type austenitic stainless steelwhich is essentially a high grade 18/8 chrome/nickel alloy steel.

PROCESSING

Dyeing

Metallized dyes give deep sbades.


Fine Strucaure and ApDearance

Grey filament of near-round cross-section. Filament diameter 4to 50 microns. Coemcient of variation of filament diameter fornominal 12 microns is approximately 4 per cent. This figureapplies to the variation from filameot to filament and also alongthe length of a particular filament.

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Hard :

AYerage Stiffness

1475-1881 cN/tex ( 167-2 l3 g/den)

Avcruge Toughness

0.019-0.024

Abmsion Resislance

High

Specific Gravity

Effect of Moisture

Absorbency: Nil.

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T T A N D B O O K O F T E X T T L E F I B R E S

Thcrnal Propefties

M eUing point : 1,426'C. aPProx.

Efrect ol IIigh Temperature

Less than l0 per cent strength loss at 426"C. Up to 90 per centtoss at 980'C.

T hennal Conductivity

Stainless steel is a poor conductor but a good resistor comparedwith copper or nickel.Stainless steel is a good conductor of heat.

F lam m a bili ty : Non-fl ammable.

Efiect of Sunligbt

Nil.

Effect of Age

Nil.

Chemical Properties

Acids

Resistant to nitric and phosphoric acids. Attacked by sulpburicand halogen acids.

Alkalis

Not affected by common alkalis.

General

The chemical properties of stainless steel fibre are similar to thoseof the bulk metal. Not attacked by common bleaches unless theyare halogen dedvatives.

Effccl of Orgrtric Solvetrts

Not attacked by common solvents

lnsecas

Not attacked.

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Micro-orSanisms

Not attacked.

Electrical Properlies

Compared with natural and other man'nade fibres, metal libresgeneially are good conductors of electricity. Compared withcopper, nickel and some other metal fibres, stainless steel is apooi conductor; stainless steel libres may bc used for rcsistanccheating.

STAINLESS STEEL FIBRE IN USE

General ChatqcteristicsStainless steel fibres have the basic mctallic fibre characteristicsalready described, providing textile goods of high modulus' hightensile strength, flexJife, tear-resistance, abrasion resistaoce andcompressional resilience. The libres have a high resistance tomany types of severe chemical and physical environments'

Etrd-Uses

The end-uses for stainless steel fibres include those described formetallic (s.c.) fibres generally.

In comparison with some other metals such as coppcr ornickel, stainless steel is a poor conductor of electricity. Stainlcsssteel fibres are particularly suitable for the production of heatcdstructures such as pads, draperies and blankets'

The thermal conductivity of stainless steel is put to good use ]in protective fabrics, the steel fibres acting as a hcat'sink that iprotects other fibres with which it is blended. Smalt conccntrn' Iiions of steel fibre (about 5 per cent) blended with 'Nomcx'high

Itemperature nylon, for example, have a remarkable cffect on Ithe high temperature resistance of fabrics' The stainless stcel Ifibre conducts away heat and prevents the temperature rising to Ia point at which the 'Nomex' becomes inadequate.

The relatively high cost of stainless steel librc has tcnded to lencourage the development of applications in which small pro- |portions of steel fibre may be blended with other fibres, to prodttcc Ivaluable characteristics such as thosc describcd. As little as l/5 |per cent steel fibre blended into a carpet yarn, for examplc' re- |duces static almost to negligible amounts.

I6e3

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t A N D B o o K o F T E * T I L E F T B R E S

Consumer Textiles

Stainless steel fibre is used in carpets, upholstery, worsted suitings,blankets, uniforms and work clolhing.

Industrial Textiles

Fiters. Because of fine fibre diameters, it is possible to designstructures with high internal surface and high fatigue life. Inconsequence, filtering emciency is increased. Using fine metalfibres in non-woven structures, with specially prepared fibre sur-faces, baltery plaques, fuel cell electrodes and capacitors can bemade.

The high temperature tolerance of stainless steel fibre is animportant adyantage in many industrial applications. For example,it is possible to caffy out high-temperature filtration of hydraulicfluids, fuels and hot gases. This has resulted in higher productionrates in many industrial processes,

Using stainless steel fibre, high efficiency operation may beachieved at temperatures up to 700'C.

Stainless steel fibres are now being used in a variety of indus-trial applications, in addition to those described. They includesewing thread, conveyor systems, cordage, fishing lines and nets,cargo restraining devices, tarpaulins, vibration isolators, heattransfer systems and paper-makers' belts.

Fibrc Reinlorcement

Stainless steel fibres used as internal support in metals, plastics,ceramics, rubber and filament wound structures have many ad-vantages. Systems of this type can meet the rigorous demands ofmany modern end-uses, providing high flexJife, tensile strength,dimensional stability and heat tolerance, The metal fibre con-ducts heat away from the matrix, which may therefore performbetter.

Applications in whicb stainless steel fibres provide reinforce-ment in this way include power belting, hosing, conveyor beltsand inflatable structures, including tyres.

Medical Applications

Stainless steel is physiologically inert, and this is a valuablo

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characteristic in many medical applications. Thcse include thcdevelopment of a cardiac pacemaker electrode systcm, whcrc goodelectrical conductivity and long-term fatigue life are esscntia[.Multifilament stainless steel yarns of fine diameters are uscd forsurgical sufures.

The ease of textile fabrication of stainless steel libres is ad-vantageous in many aspects of medical engineering, includingvascular prostheses, heart components, and orthopaedic devicesfor tendon and bone repair.

(2) METALLIC (MULTI.COMPONENT) FIBRES

Fibres made from metal in association with other nraterials,commonly plastics,

INTRODUCTION

Modern metallic fibres of the multi-componcnt typc are bascdlargely on aluminium, which provides sparkle and glittcr at afraction of the cost of the early types of decorative fibre bascdfor example, on gold.

The aluminium in these fibres is in the form of a narrowribbon-filament of either (a) metal foil, or (b) a plastic filnr whichhas been vacuum-plated with vaporized aluminiunr. 'fhis iscoated with a layer or layers of plastic lilm.

In these composite structures, the metal is protcctcd frorncorrosive influences of its environment, and from mechanicaldamage. Muliicomponent metallic fibres have achicve<l grcatpopularity as decorative fibres, and are an important facct of thcmodern textile industry.

HANDBOOK OF TEXTILE F I B RES

TYPES OI: METALLIC (M.C.) FIBRE

In the U.S., the former Metallic Yarns Institute established mini-mum quality standards for metallic (m.c.) yarns for textile pur_

ivletallic (m.c.). fibres may be made in almost infinite varietv bvusing different metals and plastics in their manufacture. Alumin-ium is, however, the ntetal most commonly selected, and it issandwiched between cellulose acetate butyrate, cellophane (cellu-lose) or polyester films.

The following are the types of yarn commonly produced:

(l) Acctate Bulyrate, Aluminiunr Foil. A continuous flat mono-filament composed of aluminium foil Iaminated on both reflectivesurfaces with cellulose acetate butyrate film.

(2) Cellophane, Aluminiunt Foll. A continuous flat monofila-ment composed of aluminium foil laminated on both reflectivesurfaces with cellophane film.

(3) Polyester, Aluminiunt Foil. A continuous flat monofilamentcomposed of aluminium foil laminated on both reflective surfaceswith polyester film.

(4) Polyester, Aluminiunt Metallized polyester. A continuousflat.monofilament composed of aluminium metallized polyesterlaminated on iis metallized surface or surfaces with polyesterfilm.

(5) Polyeste r, Aluminiun Metallized, Non-Laminated. A con_tinuo[s, flat monoRlament composed of a single layer of alumin-ium metallized polyester protected on its metallized surface.

The acetate butyrate types of metallic fibre are best used forapplications which are not subjected to wet processing of otherthan very mild forms. Polyester types will withstand

-wet treat-

ments or dry-heat operations as commonly used with most man_made fibres, but reference should be made to manufacturers'recommendations regarding time, pH and temperature conditions.

NOMENCLATURE AND TERMINOLOGY

696

t ' t _ l t : t ' L ' L 'l - - t_ i - t_ : t ' t ' u

D : S Y N T T I E T I C F I N R E S

poses (see table on page 698), and prcscribcd a strndard systcnrof designation and tcrms of refcrencc for thcsc yarns.

The following definition of a nrctallic yarfr was cstablished bythe lostitute, and in general it is stil l in common use:

Metallic Yant. A continuous flat monofilamcnt produccd by acombination of plastic film and metallic componcnt so that thcmctallic componcnt is protected.

This definition dillers somewhat fronr thxt cstablishcd by thcU.S. Federal Trade Commission (see page xxvii).

TerminologyMetallic yarns are designated by a group of threc synrbols, cachseparated by a hyphen, setting forth the two dimensions o[ width,and gauge or thickness, and generic type.

1. Width. The width of thc yarn is expressed as tlrc frnction ofan inch to which the yarn has been cut, viz., 1132, l/64, ctc.

2. Gauge (or Thickness\. The thickncss or gauge of thc yarnis expressed as the sum of thc thickness of thc plastic filnr andmetallic component in hundred-thousandths of an inch, as awhole number, v i2 . ,35,50, 150,200, etc .

3. Generic Type. The type of the yarn is expresscd on the basisof two components of the laminate - the gcncric namc of thcplastic film and the metal.

The components are separatcd by a comma, viz., Polycstcr,Foil.

Exantple: A Polyester, Aluminium Foil Yarn, l/64 inch widcand 150/ 100,000 inch thick, is cxpresscd in the industry as:

| 164 - 150 - Polyester, FoilA manufacturer's trade name or mark may accompany, but

where utilized, either alone or in combination, thc abovc mustbe separately stated or refetred to.

METALLIC YARNS - STANDARDS

following minimal standards were cstablished for mctallic

a | /64- inch w id th

l ' i\ ' \ ' \ '

by the U.S. Metallic Yflrns Institlrle.determining standards for basic yarns,

697

t r t t t t t lI \ \ I

rnsIn

zr

I

Theya

I t

2

l lL

- Fth-hlt

arithmetic proportion.

PRODUCTION

Modern metallic filaments are made by sandwiching a thin layerof metal, usually aluminium, between thin sheets of the appro-priate types of plastic film. There are several ways of carrying outthe lamination.

In the production of the Acetate Butyrate, Aluminium Foil(Type 1) metallic fibre, for example, a thermoplastic adhesive isapplied to both sides of a sheet of aluminium 0.01 nrm (0.00045in) thick. The adhesive may or may not be coloured. The coatedfoil is then heated to about 90'C., and it is passed through a set


of rollcrs together with lwo shccts of ccllulose acetate butyratc,in such a way'that lhe aluminiunr foil bccomes the centre of thcsandwich.

The laminated material is then slit into narrow ribbonlikef i laments of the desi red width. e .g. 3 .2-0.2 nrur ( l /8- l /128 in) .

In some types of metallic filament (c.g. Types 4 and 5), thecentre of lhe sandwich consists of a plastic (e.g. polycstcr) filmwhich has been vacuum-coated with aluminium. This may thenbe protected with layers of lacqDer or plastic film as above.

Many types of coloured metallic filament are now produccd,the metallic glitter of the aluminium shining through the colourcdadhesive or the coloured outer plastic films. Gold-coloured fila-ments are made, for example, by using an orange-yellow dyestuflor pigment in the adhesive; silver is obtained by relying only onthe natural glitter of the aluminium.

Pt{ocEsslNG

DcsizingConventional techniques and equipment may be uscd for polycstertype metallic yarns.

ScouringPolyester type yarns are best scourcd on ropc or opcn-widthmachines, the squeeze roilers being adjusted to give as light anip as possible in order to avoid unnecessary damage.

trleachingPolyester type metallic yarns may be subjcctcd to nornal blcach-ing operations. Care should be taken to minimize exposure toalkaline conditions, temperatures in excess of 90"C. and prolongcdcycle times.

Nore. Coated polyester yarns are not recommendcd for hightemperature conditions, i.e. in excess of 70"C.

Dyeing

Some metallic (m.c.) fibres may be dyed eftectively, the techniqucsand dyes being selected according to the type of plastic in the

Type

ColourToleraoceto Light

BreakingElonga-Yield (hrs.)Yield Strength tion Pt. (Gold and

(yd./lb.) (e.) (%) (g.) silver)

l^ 270 Acctate Butyrate,foil

lB 310 Acetate Butyrate,foil

2 230 Cellophane, foil3 150 Polyester, Alum.

foil4^ 100 Polyestcr, Alum.

Metallized Poly-ester

48 l5O Polyester, Alum.Metall ized Poly-ester

5 50 Polyester, Alum,Metallized, Non-Laminated

18,000 2i0

10,500 t60 30 10 100

t0,000 170 30 100 i0010,000 200 20 n.a. n.a.

16,000 r75 80 t2s 100

28,000 t75 t0090

t25

8()

80 r00

40 10047,000 90 80

n.a.:not available.

698 699

H A N D B O O K O F T E X T I L E F I A R E S

fibrc. The acetatc butyrale types should be treatcd generally asacetatc, and dyeing carried out at ternperatures not exceeding70'C. Polyester yarns may be dyed at the boil, with the exceptionof most coated types.

It is generally more satisfactory to make use of colouredmetallic yarns where possible, rather than to dye the metallicyarns in the fabric. Dyeing problems are commonly concernedwith the avoidanc€ of colouration of the metallic yarns duringthe dyeing of the base material of the fabric. This is usually amatter of careful choice of dyes, avoiding those which dye theplastic in the metallic fibre,


The properties of a metallic (m.c.) fibre depend upon the natureof the plastic film used in its production, and of the metal used asthe centre of the sandwich.

In general, the fibres behave in a manner similar to n.rpn-madefibres spun from polymer on which the plastic film ls based.Acetate butyrate metallic filaments, for example, have a resem-blance to acetate fibres; polyester type metallic filaments aresimilar to polyester fibres in their general characteristics.

The nature of the aluminium layer inside the sandwich alTectsthe properties of the metallic filament to a significant extent.ln Types 1,2 and 3, the aluminium is a continuous layer offoil; in Types 4 and 5, on the other hand, it is in the form ofdiscrete particles which have been deposited on a layer of plasticfilm. The discontinuous layer of the latter types results in afiner, softer and more pliable filament, with properties which dillerin many respects from those of the foil-type metallic fibres, asindicated below. The figures quoted refer to specific metallicfibres of the various basic types, but there is considerablevariation in properties between nbres of the same type.

Fine Struc(ure and Appcarance

Metallic (m.c.) fibres are flat, ribbon-like filaments, commonly3.2-O.2 mm (ll8-lll28 in) width. They are smooth-surfaced,and may be coloured or uncoloured.

700

-L_i L_: L't_i u t_i [_' t] Ll [ ' Lji L] I ' � Ll L_i L_i Li Li \ '--1 '


'Icnsilc Slrcnglb'fhc standarrls originatly sct up by thc fr4clallic Yartls lnstiltrtc'U.S.A., are shown in the table on pagc 698 '

fetracity

Acetate Butyrate, foil: 2.6 cN/tex.(0.3 g/dcn;'Polvester. foil: ().2 cN/tex (0 79 g/tlen).Polyester , rncta i l ized: | 1 .0 cN/ tex ( 1 .25 g/ t le t t ) '

Elongrlion

See table on page 698.Acetate Butyrate, foil: 30 Per cent.Polyester, foil: 140 Per cent.Polyester, metallized: 140 per cenl.

Yield Point

See table, page 698.

Dlasaic Rccovcry

Acetate Butyrate, foit: ?5 per cent at 5 per cent clongalion'Polyester, foil: 50 per cent at 5 per cent elongation.Polyester, metallized: 100 per cent at 5 pcr ccnt elongation'

trlex Resisaanc€

Relative flex resistances of the main types arc in thc followingratlos:Acetate Butyrate, foil: IPolyester, foil: 18Polyester, metallized: 70

Abrasion Resistance

Acetate Butyrate, foil: fair.Polyester, foit: good.Polyester, metallized : excellent.

Effect of Moisture

Regain: Acetate Butyrate, foil: 0.1 per cent.PolYester, foil: 0.5 Per ccnt.Polyester, metallized: 0.25 per ccnt.

701


Tbermal Prop€rties

Softening point:

Efrect of Age

Nil.

Acetate Butyrate, foil: 205'C.Polyester: 232'C.

Effect of Sunlight

Some loss of strength on prolonged exposure.

Chemical Properties

Acids

Generally good resistance.

Alkalis

Acetate Butyrate: good resistance to weak alkalis; degraded bys t rong a lka l i s . IPolyesler: ditto. Metal foil types are more resistant.

Generql

Acetate Butyrate: Similar to acetal€ yarn. Not affected by sea-water, chlorinated water, or perspiration. Generally resistant tobleaches, but sensjtive to caustic soda used in peroxide bleaching.Also sensitive to copper sulphate and sodium carbonate at hightemperatures,Polyester: Generally good resistance.

Effect of Organic Solvents

Acetate Butyrate. Attacked by acetone, ether, chloroform,methyl alcohol, tetrachloroethane. Not attacked by benzene,carbon tetrachloride, ethyl alcohol, perchloroethylene, trichloro-ethylene.

Polyester. Attacked by acetone, benzene, chloroform, tetra-chloroethane, trichloroethylene. Not attacked by carbon tetra-chloride, ethyl alcohol, methyl alcohol, perchloroethylene, whitespirit.


Insecas

Not attacked.

Micro-organisms

Not attacked.

AllergeDic Properties

Non-allergenic.

Electrical Prope ies

Metallic (m.c.) fibres conduct electricity, the metallized types

having a lower conductivity than the foil types.

METALLIZED (M.C.) FIBRES ]N USE

Gencral Char:rclerisaics

AppeardnceMctallic (nr.c.) yarns are used in thc textile industry almostentirely as decorative matcrials. Thcy providc a mctallic glittcrand soirkle that cannot be obtained in otber ways. The aluminiumfoil ihat provides the glitter in a modern mctallic yarn is-pro-tected from corrosive materials of its environment by the plasticfilm in which it is enclosed. It remains untarnished through longperiods of wear, and polycstcr typcs will withstand repeatcdiaunderings without losing their sparklc. Metallic yarns arc nota{Iected by seawater ol by the chlorinated water of swimmingoools. and are widely uscd in modcrn swimwcar.^

The dvestutrs used in colouring metallic fibres are usually fastto light, and the colour remains bright to match the sparkle fromthe aluminium foil.

Mechanical ProPerliesAs metallic (m.c.) yarns are used primarily for decorative pur-

Doses. they do not as a rule contribute significantly to lhcitrength oi fabrics or garments. Nevertheless, they may bc lscd". *ift o. warp yarns, and are strong enough to withstand theweaving and knitiing operations. If necessary, the metallic yarns

are combined with support yarns, such as n}'lon.The plastic film of the metallic yarn is flexible, and the yarns

are extensible to a degree that depends upon the type'

703

H

N D D O O K O F T E X T I L E F I B R E S

Chcurical PropertiesAluminium will corrodc and tarnish in air, and in contact withseawater, but in metallic fibres it is protected so effectively thatit retains its glitter for long periods. The chemical resistance ofa metallic lilament is, in general, the chemical resistance of theplastio film. In the case of polyester films, this is outstanding.

If metallic fibres are held in contact with strone alkalinesolutions for prolonged periods, the aluminium may bi attackedat the unprotected edges of the ribbon. Metallic fibres shouldnot, therefore, be subjected to alkaline reagents of significantstrength.

Organic solvents, too, may attack the laminate adhesive orlacquer coating; grcat care should be taken in dry cleaning toensure that an appropriate type of solvent is used,

Thernnl PropertiesThe plastic films in nretallic fibres are thermoplastic. and willsoften at clcvated temperatures. Dclamination mav occur it thefibres are hcated. and acctalc typcs in particuiar lhould bcprocessed only at low temperatures.

The plastic films may be permanently embossed by heat andpressure, and special effects may be introduced into the fibres inthls way.

Washing

Acetate butyrate types may be hand washed in lukewarm waterwith a mild soap. If processed as silks or woollens, they may besafely washed in home or commercial laundry equipment.

-

_ ?olyester -types may be washed at temperatures up to 70.C.Dimensional stability is good and crease resistance fair.

Most coated polyester yarns will not withstand treatments otherthan those used for silks or woollens.

Drying

Acetate butyrate types must be dried at as low a temperature asposs-ib-le. Polyester types may be dried at higher tempcratures asused for polyester fibres, with the exception of most coated types.

lroning

Acetate butyrate types should be ironed at temperatures no higher

704

T II L ' [ ' t ] L _ l L ' � I ' � [ ' L _ ] [ ' � L ' L ' � l - ' � L ' � L ] L l L _ i L _ i L _ i

B: S Y } . ITH ET I C F INRES

than I05'C. Polycslcr types may bc ironcd at tcmperaturcs upto 130"C. 'l layon'setting is preferable for both typcs.

Dry Cleaning

Metallic fibres may bc dry cleancd without ditliculty, providedcare is taken in the selection of solvent to suit the typc of fibrc.

End-Uscs

Metallic (m.c.) yarns are used for decorativc purposcs in almostevery lield of textile application. Important end-uscs includewomen's dress goods, upholstery, curtains, table linens, swimwear,packaging, footwear, car upholstery, suits and hats.

705

l-, r*r I- r r r r' ' t, n J-'Ja FH A N D B O O K O F ' I I i X T I L E F I B I I E S

706

B : S Y N T H E T I C F T B R B S

POLYUREA FIBRES

Fibres spun from synthetic linear polymers containing the urcagrouping, -NH-CO-NH-, as part of the repeating unit.

DIAMINE

INTRODUCTION

Following the introduction of nylon, many types of condensationpolymer were examined as possible sources of synthetic fibres.Among those considered as vr'orthy of detailed study were thepolyureas, formed by condensation of diamines with utea' andihaiacterized by the recurring urca group, -NH-CO-NII-'

in the polymer molecule.Polyurea fibres were spun in America, Gcrmany and thc U.K.

during the 1940s, but despitc a considcrable rcsearch ellort thcydid n;t yield a fibre that was selected for commercial develop-ment. It was not until 1950 that polyureas again canre undcrintensive investigation, this time in Japan, where the nrm ToyoKoatsu lndustries Ltcl. began seeking nerv outlets for urca.'lhischemical, produced in ver/large quantities, is a che:rp llld rcr(li lyavailable raw material for the production of synthetic products.There is an obvious attraction in using it as the starting pointfor the marufacture of synthetic fibres'

within 5 years, Toyo Koatsu had developcd a laboratory-scaleprocess for the production of a polyurea libre made by condcns-ing urea with nonamethylene diamine.

nNH, (CHr) NH. +

NONAMETHYLENE DIAMINE

nNH2 CONHT

UREA

----> {t

",y" NH coNH l-

+ 2n NH'

POLYUREAProluclion of 'Urylon'

70'l

nNH, -R-NH, + NH2CoNH2 . - - - - ' . fn - runcoNl |

+ znHH'

UREA POLYUREA

Productiol o! Polyurca


By 1958, a pilot plant was in operation, producing I ton perday of the polyurca fibre - now known as'Urylon'- and itseemed likely that large-scale development would be undertakenin a matter of a year or two. Since then, however, 'Urylon' hasmade little apparent progress as a commercial fibre.

The properties of 'Urylon' are comparable in general with thoseof nylon 6.6 and PET polyester Rbres- The fibre melts at 240"C.and has a tenacity of 39.7-48.6 cN/tex (4.5-5.5 g/clen), with anelongation of 15-20 per cent. It has a low specific gravity -- 1.07 -which makes it the lightest synthetic fibre other than polyethyleneor polypropylene. 'Urylon' has good chemical resistance, moistureregain of 1.7, and in other respects seems eminently satisfactoryas a textile fibre.

The problem with 'Urylon' and other polyurea nbres lies notin the characteristics of the fibre itself. but in the economics ofproduction. Urea is cheap and plentiful, but nonamethylenediamine is expensive; it has been made until recently almostentirely from rice bran oil.

In the section which follows, information 5n polyurea libresrelates primarily to'Urylon', and was provided by Toyo KoatsuIndustries Ltd.

PRODUCTION

Polyurea used in 'Urylon' production is made by tbe condensa-tion of urea with nonamethylene diamine (see page 707).

Monomer Synthesis(a) UreaUrea is manufactured on a very large scale by the reaction ofcarbon dioxide with ammonia at high temperature and pressure.Ammonium carbamate is formed (1), and this decomposes toyield urea and water (2).

708

r - lI

' l r l l lt

r l ' [ '� l r l ' l i L l Li ti t_i-


I t I t r \2NHr + CO2 + NH, COONH{ -r:r+ NH?CONI|, + HrO

AMMONIUMCARBAMATE UREA

Prcdtctiort ol Urco

(b) N onantet lrylerte Dianri treRice bran oil contains oleic and linolcic acids. Whcn thc oil isreacted with ozone, the oleic acid forms pelargonic acid andazelaic acid (l), and the linoleic acid forms caproic acid andazelaic acid (2).

The azelaic acid is reacted with ammonia to form ammoniumazelate (3), which is dehydrated to azelaic dinitrile (4) and thcnhydrogenated to nonamethylene diamine (5).

Note. -Ibe produciion steps from azelaic acid are similar tothose used in making hexamethylene diamine from adipic acidin the production of nylon 6.6

(a) cH, (cH,), cH = cH (cH,), CoOl{ + zo, -lJI.

OLEIC ACID

cHr (cH,)7 cooH + Hooc (cHr), cooH

PELARGONIC ACID AZELAIC ACID

(B) cH! (cH,)5 cH = cH - cs = cH (cHr)r cooH + 20, g

LINOLEIC ACID

cH3 (cH')! cooH + Hooc (cH'), cooH

cAPROtC ACIO AZELAIC ACID

(c) Hooc (cH,),cooH + arx, J:)- 1.",rr(:::::.' \cooNHrAZELAIC ACID

/ / \ , "CN a<l-!:-1+ fCH^) ----l:r+-

- c t t

AZELAIC DINITRILE

Prcduction ol Nonanctltyle e Diantine

709

AMMONIUM AZ€LATE

,/2CH2 NH2

(cH-). ..,\cr, *",

NONAMEIHYLENE DIAMINE

r. F. l'. F F. |., l-.FJ'nF.FIn

IH A N D B O O K O F T E X T I L E F I B R E S

Polyme.izaaion

Nonamethylene diamine and urea are dissolved in water, using aslight molar excess of diamine. The solution is heated at atmo-spheric pressure, the temperature being raised from 100'C. toabout 250'C. over a period of 15-18 hours. Vacuum is appliedin the final stages.

The polymer is milky-white, with a melting point of 225 231"C.It contains only a very small amount of low-molecular-weiglrtmaterial, and may be spun directly.

SpinningThe polyurea is melt spun, and is hot drawn, c.g. in three stagesat l00o C. ( to prov ic le f ib re of tenaci ty 48.6 cN/ tex; 5 .5 g/ ( len ) . I ris wound on to bobbins. and ntay be cut in to s taple.

PROCESSING

DyeingPolyurea fibre may be dyed with acid, disperse, direct and vatdyes. The polymer molecule provides excellent anchor-points foracid dyes at the twin imino groups of the urea linkage, and at theterminal amino groups.

Acid dyes provide colours of good light and wash fastness.Tannic acid treatment is recommended to increase fastness,

Sulphur and basic dyes are not satisfactory.


l-ine Strucaure and Appearancc

Smooth surfaced filaments of round cross-section.

Tenacih/

39 .7-48 .6 cN/ tex (4 .5 -5 .5 g /den) .

Elongalioo

15-20 per cent.

B : S Y N T } I E T I C F T B R E S

Elasaic Rccovery

70 per cent recovery from 8 pcr cent exlension aftcr 30 seconds;92 per cent recovery after 5 minutes.

Spccific Gravily

1 .07 .

Dflcct of Moislurc

Regain: 1.8 per cent.Hydrolysis occurs on exposure to stcam at 130'C.

Thcrmal Propcrai€s

Soltening point: 205'C.

Mehittg point: 240"C.

ElJect ol I Iigh Tunpcmtnrc

Some loss of strength on continucd exposure to air at 150.C.

Eltcct of SuDliglrt

Similar to nylon.

Chemical Propertics

Acids

Good resistance. Retains morc than 90 per ccnt strcngth aftcr l0hours at roont temperature in 40 per cent sulphuric acid.

Alkalis

Good resistance. Retains more than 90 pcr ccnt strcngth l l l lcr t0hours at room temperature in 40 pcr cent caustic soda.

General

Cood resistance to most common chenricals.

Eflcct of Organic Solvcnls

Similar to nylon.

lnsecas

Not attacked.

7lo 7 t l


Micro"organisms

Not attacked.

POLYUREA FIBRES IN USE

General Characteristics

Handlc, etc.Polyurea fibres have a soft, attractive handle, and fabrics arecomfortable and warm when worn next to the skin.

Mechanical ProperliesIn general, the mechanical properties of polyurea ftbres arecomparable with nylon 6.6 and PET polyester Rbres, with acloser resemblance to nylon.

T hennal ProperliesThe melting point of 'Urylon' lies slightly below that of, rrylon 6.6,and above that of nylon 6. Thermal stability is gdod up to140"C., but the Sbre degrades on exposure to temperatures abovethis.

In common with other thermoplastic fibres, polyurea fibresmay be heat set, e.g. by heating for lt minutes at 160'C. Thefibre shrinks 13 per cent at 180'C.

Clrcnical PropefliesPolyurea fibres have excellent chemic:rl stability. They resist acidsbetter than nylon, and alkalis better than PET polyester fibres.

MoistureWith a regain of 1.8 polyurea fibre has a lower moisture absorp-tion und€r standard conditions than either nylon or PET polyesterfibres. This could be a disadvantage in apparel uses.

Specific GravityPolyurea fibre is tighter than any synthetic fibres other thanpolyethylene and polypropylene. This could nrean greater cover-ing power than nylon or polyester fibres, with which it seemslikely to compete.


DyeabiLity

It is not possible to predict at this stage lvhcther dycability willbe signilicantly bctter than that of nylon, but it sccrns problblcthai this will be so.

Ilnd UsesThe end uses of polyurca libres will lie in the sanc hclds as thosco[ nylon and PET polycster fibrcs.

Ittdustrial UsesPolyurea fibres will probably find a useful outlet in fishing lincs,nets and ropes, where its lightness will be advantageous. It couldprove a useful reinforcement fibre for tyres, conveyor belts andthe like.

Apparel UsesPolyurea fibres could find a variety of applications in theapparel field similar to thosc scrved by nylon. Thc lowcr nroisturcrcgain nray provc disadvantagcous in this rcspccl.

713712

' l I l ' l ' l ' l t ' l t I I t I I r l : t ' t i L i L i t _ i

' r lnn -F .L : - - trrtH A N D B O O K O F T E X T I L E F I B R E S

POLYCARBONATE FIBRES

Fibres spun from synthetic linear polymers containing thecharacteristic grouping -{--{O-O- as part of the repiatingunit.

INTRODUCTION

CHt

Hotr\-E-CH.

| .z-r -l-c-( \)o--c- | cl

| \:,/

JaCH, O

Polycarbonate resins have been used for some years as plastics,their applications being determined largely by their- usefuielectrical ald high-impact-resistan€e characteristics. Melting pointsare_ typically in the region 150-300.C., and some of the-poly_carbonates have good spinning properties. The low cost oi thLestarting materials has sustained an interest in fibres spun frompolycarbonate resins, and monofilaments are produced commer_cially on a limited scale.

(b) Carbonic Acicl EstcrsAn cster of carbonic acid, such as diphenyl carbonatc, may bctrans-€sterified with bis phenols:

/*o,^\ | ,r-\, ' I r o ( ) - c ; ( ) o r r r , o - c| \_,/cl-t3 t*O

cH,-l*a\"-. -l .,',,,.:' 3 -l'

',[-"O c_)Filaments are nlelt spun.

STRUCTURE AND PITOPIR]'IES

Tenacity 16.8 cN/tex (L9 g/rlen)Elongation 40,6O,,/o

lnitial Modulus 397.3 cNitcx (45 g/tlcn.y

POLYCARtsONA'|E FII]RES IN USE

Monofilaments are used as temporary threacls, c.g. b:rsting thrcrtlsin men's suits which can be renrovetl subserlucltly by solvt'nttreatmellt in a dry cleaning nrachine.

CII3

In the chemical sense, polycarbonates are polyesters derived fromcarbonic acid, H,CO". They do not qualify for the descriptionpolyester, however, under the U.S. Federal Trade Commiisiondelinition.

PRODUCTION

Polycarbonates nay be made by condensing an aromaticdihydroxy compound with suitable carbonic acid derivatives, e.g.carbonyl chloride (phosgene) or esters of carboiric acid.

NOMENCLATURE

(a) Corbonyl Chloride (Phosgene)

Carbonyl chloride nray be condensed,p'-isopropylidene-diphenol (,Bis phenolobtainable from phenol and acetone. Inthe following reaction takes place:

for example, with p,A'), which is readilythe presence of alkali,

B : S Y N T H E T I C F T B R E S

ct cl"/ T l-\

OIt * rr C -> l: l -O(/ )1 L \ : /o

714 7 1 5

I T A N D B O O K O F T O X I ' I L E F I B R E S

CARBON FIBRES

INTRODUCTION

ln 1963 a team of British scientists. W. Watt. W. Johnson anclL.N. Phillips, working at the Royal Aircraft Establishment.Farnborough, U.K., developed techniques for proclucing carbonfibres of high strength and outstanding rigidity. Theie fibreswer€ in commercial production by 1968 and have since becomeof great importance, especially in the field of composites in whichthe fibres are embedded in resins or other materials.

Most of tbe important textile fibres in use today are derivedfrom organic polymers, i.e., polymers in which the backbone ofthe molecular structure consists of carbon atoms to which areattached atoms of other elements, conrmonly hydrogen, oxygenand nitrogen.

It has long been known that pyrolysis of these fibres, such asrayon, could result in the rernoval of the nonparbon atoms toleave a filament consisting essentially of carbon. But the carbonatoms in these filaments are arranged in a more or less disorderedform; the structure is amorphous iather than crystalline, and thefilaments are weak and of little practical value. To achieve highstrength and nrodulus, it was necessary to devise a process forproducing carbon fibres which would orientate the carbon atomsand result in fibres of a high degree of crystallinity.

PIIODUCTION

The starting material for production of carbon fibres is comnronlyan acrylic fibre, such as 'Courtelle', in which the backbone ofcarbon atoms is attached to hydrogen atoms and CN groups. Athree-stage heating process is used in converting the acrylic fibreIO CatOOn.

The initial stage is to heat the acrylic fibres at 200-300oCunder oxidising conditions. This is followed by a second stagewhen the oxidised fibre is heated in an inert atlnosDhere totemperatures around l0000C. Hydrogen and nitrogen aioms areexpelled, leaving the carbon atoms in the form of hexagonalrings which are arranged in oriented fibrils.

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B : S Y N T I I E T I C F I I T I I I ' S

F inal ly , thc carbonized l i lanrcnts l rc hc l tc t l to t ! ' r rpcr i l lur r 'sof up to 30000C, agai r r in au incr t a tnrosphcrc. ' l l r is i r rcr r 'ascs theorderly arrangeurent of the crrbon atonrs rvhich arc oLqirniz.e(lin to a crysta l l ine s t ructure s i rn i lar to that o lgraphi tc . lhc l tornsare in layers or p larres rvh ic l r l ie v iL tur l ly p l r r l lc l to c lch ot l r r ' r .' lhe p lar tes arc wcl l or icr tc( l i r r thc d i rcct ion o l thc l lbrc lx is ,this being an inlportant factor in producing ltiglt rrtorlultrs l ' i lrrt's.' l 'he nrechauical propertics of carbon librcs prorlucctl in tlrisrvay are afl'ected greatly by thc conditiorrs rtncler rvhiclr tlrcy rrt'treated in the final stage, ald by varyirtg tllcse colditior)s it ispossible to produce fibres of diflcrent ntodulus lrttl strcttgtltcharacteristics.

STRUCTURE AND PROPERl'IES

' l 'he proper t ies of carbon f ibres vary, dcpet t t l i r rg on thc cor l ( l i t ior lsuntlcr whiclt they arc p rotluccd .

' l ' ltc itt fo rtrt:t t iott rvlrich lirllorvsrelates to a typical range of fibrcs.

Fine St.ructure antl l ltpcarattcc. Clrbort libres rrc ltl lck rttdsnrooth'su rfaced, with a silky lustre. ' l 'hey lre cttttttttottly ttl-round cross-section, possibly rvith flattencd sidcs.

Ultirnate Tensile Strength. I.8O-2.40 kN/rnrrr2. (cf. stccl 2.80'4.00).

Brcokitrg lixtcnsbn. 0.5'/". (ct . stccl 2.O'/o).

Densi ty . 1 .95 g icnr3.1cf . s tec l 7 .80) .

Stiffness. 350-4 I 0 kN/nrrn3 (cf. stccl 207).

Stiflnessllleight Ratio. 180-210 (cl. stccl 27).

Elastic hopcttics. Loacl/extertsion curve altttost lintrr to brcali.I lookean behaviour . Per lect ly c last ic to brcrk.

Specific Cravity. I .75- I .85 .

Eflect of tr'loisturc. Ntl.

'h -t--T- I- r r- r II I A N D B O O K O I " I l t X l l L E t : l l ] l l I r S

Flannnbility. Not fl arnnrable.

Eflect of Age, Jal/rgftt, Nil.

[flbct of Chenicals, Sobents. lnert. I Iot air oxitlation ancl strongoxidising agcnts (e.9. sodium hypochlorite) cause sonre erosion.

Effects of hrects, Microtrganisnts. Nil.

CAIII]ON FItsRE IN USE

INDI'X

Carbon fibres arc characteriseci by high strength aud grcat stiffnessagainst bending and twisting forces. Steel fibres, rvhich approachnearest to carbon in stiffness, are four times as clense as carbon,ancl carbon fibres have a very nuch superior stiffness to weightrat io .

The breaking extension ofcarbon f ibres is low, and unsupporte( lfibres are brittle. Applications lie very largely in the lleld ofcomposites for specialised uses, where the high cost oI carbonIlbre relative to steel, glass and other reinfofcing fibres is ofmininral consequence. Carbon fibre composites are used, forexantple, in aircraft structural components, in brakes ancl engines.They have provecl of inrmense value in space vehicles, whereweight reduction is at a premium. As carbon fibres beconrecheaper with increased production, they are finding their waysteadily into more mundane applications such as golf-club shal'ts,fishing rods, boats and submarines, pressure vessels in the chenricaland a l l ie t l industr ies.

Special grades of carbon flbre are usecl in prolective clotiringfabrics, rvhere their inertness and heat resistance serve then well.Carbon fibre labrics nray bc rvashed at 40oC (HLCC 6) and driedrvith a short spin tumble clry or calender. They nray be ironecl andcl ry c leaned.

Acetate f ibres, 80, 82Acctyl value, 82Acryl ic f ibres: scc l 'olYacryloni

tr i le (acryl ic) f ibrcsAcrylonitr i le, 393, 399Adipic acid, 2l l'A' glass, 644Alginate f ibres, 7, 148Alsinic acid, 148Alkal i cel lulose, l2Alpha-cel lulose,66Alpha-kelat in, xi i iAluminium alsinate, 149Alunrinium si i icate f ibrcs, 666Amcrican Viscosc Corporation

process, l9Anrino acid, I l59-anrino-nonlnoic acit l , 319I l '^mino-undecano ic acid, 292Amorphous regions, xxiAnecl 's Hair, 641Aramto l lD tes , J I J'Ardi l ' , 135'Arncl ' , 101Artificial silk, 8As tbu ry , P ro f . w . T . , l l 5Atactic polyproPYlcne. ;566Audemars, Georgc, 5'Avccranr' , 189Azlonr see I ' rotcin Fibrcs

l l .T.C, dcf init ion, xxvi i , I l6

Basified viscosc, 39B c a d l e , C , 9Bemberg , J .P . , 65l leryl l ium alginatc, 149l leta-keratin, xi i iB e v a n , E . J . , 9 , 8 0Bicomponent f ibrc

acryl ic, 413g lass ,64 ln v l o n . 3 0 6ny lon /po l ycs t c r , 323

l l iconsti tucnt f ibreny lon /po l ycs te r . 323

Bobbin sninning, viscosc, l6Box sninir ing. viscose, l5

Bra ching, rt lolecular, xxi iBubblc-l i l lcd viscosc, 2lI lulkcd nylon, 306

L^alciurn alginatc, 149Caprohc ta r r t , 262Capryl lactrf i l , 317Cirbon f ibrcs, 716Carothcrs, Wallacc I I . , 196, 328L t s c l n I l D l c s . l r /Cclhrlosc acctatc, 80

n r i n l a r y , 8 l , 8 2s c c o n d a r y , 8 l , 8 2

Cellulose acctate f ibrcs: sdcAcetate, fr iacetatc

Ccllulosc dircctatc, 81, 82Collulosc cslcr f lbrcs, ?9Ccllr losc t ibrcs, xi i , 9Ccllulosc nitrntc, 4Ccllulosc. rcacrtcr i l tcd, f ibrcs: str '

Cupro, Saponit icd ccl luloscester, Viscosc,

Ccl lulosc tr iacctatc, 81, 82Ceramic f ibrc, 667

c]," i i i - t l .n.t i inc, cffccts of, r \ i iChardonnct, Co-unt l l i lairc de, 5Chardon|lct si lk, 5Chibnall , I ' rof. A. C., I l5C l r l o ro f i t r r o ,446Collaqcn f ibrc, 146Continuous f i lanlcnt ycnls, xvi iContinuous spirning, viscosc, l6Coronization, 655Cotton, viscosc rayo fron), I ICrinrpcd viscose, 21, 22Cross, C. I ; . , 9, 80Cross-l inked nylon, 30?Cross-l inked rayon, 38Cross-l inking, cffccts of, xxi iCross{inks, \ ,ool, xi i iCtoss-section, cl fcct on propcit ics.

4 1 0Crj 'stal l i | lc-.rtrorphous tt t io, xiCrystal l ini ty, xi , r ixi

strctching ard, xx

7 1 8

Cuprarnmonium tayon: JeeCupro

discovcry of, 6C u p r o , 6 , 9 , 6 5

'Darvan ' ,523Dcnaturing of protein, l l6Dcspeissis, Louis Henry, 65ulawtng, xxDrcyfus, Henry.and Camille, 8lury sptn tng, xlx'Dura f i l ' ,40'Dyne l ' ,468

Egg albumirt fib.e, 147'E'glass, 644Elastic threads, 154Elastomer, 156Elastomeric fibre, 156, 611, 615Ethy lene,541Ethylene glycol, 332

Feather protein fibre, 147Irederal Trade Commission Fibre

Identif ication Act 1958, xxviFEI' fibres: see Fluorinated cthv-

lere-propylene copolymer'trllres-

Ferretti, Antonio, 117Fibre classification chart, xxxI;luorinatcd ethylene-propylcne

copolymer fibres, 519Fluorocatbon fibrcs, 510I;luoropolymcf fibres, 510'For t i san ' ,75l:remery, Max, 65

Glass fibres, 639Globular proteins, 115Godet wheel, 15Graft polymerization, nylon, 308Grafted rayon staple, 38Groundnut p ro te in f ib re , 135

I'leat cleaning, glass, 654Ileptanolactam, 3l 3llctcrofil fibres, 306Hevea brusiliensis, 153

Hexamethylenc diaminc, 2l Illigh bulk fibres

acrylic, 398, 413n y t r i l , 5 3 l

High-temperature fi bre, 667tligh tcnacity viscose rayon; see

Viscosc (lrigh tcnacity) rayonHigh wct f ltodulus viscose rayo :

sec Viscose (high wetmodulus) rayon.

Hooke, Robert, 3

Identif ication, nylor, 6 and 6,6,286

Incorporated rayon staple, 38lndustrial Rayon proccss, l?Inorganic fibre, 66?lsoprene, 159lsotactic polypropylene, 566

Keratin, xii i'Kev la r ' ,325Kohorn Oko|natic process. 20Kuljian prqcess, l!i

'Lanital ', l l7Lastlile, F.T-C. definition, xxviii

443Lauryl lactam, 321Lil ienfeld,40

Maizo protein fibrc, 141Man-nladc fibres, classification,

xxlv, xxv'Marena' collagcn fibre, [46Meld ins ,306Nlelt spinning, xixMercerizing, viscose, 30Metallic fibres, 678

F,T,C. definition, xxvii, 680introduction, 678multi-conrponent, 678, 695nomcnclature, 680single-conrponent, 679, 680types ,679

Metcll ic (nlult icomponent) f i brcs;metauic (m.c.) f ibres, 695

Metallic (single-cotrponent) fibres;metallic (s.c.) fibres, 680

Metallic (stainless steel) fibrcs,690

Mineral silicatc fibres: J?eSilicate (mineral) fibrcs

Modacrylic fibres: see Polyacry--lonitrils (modacrylic) fibres

Monkey nut f ibre: tec GroundnutDrotcin librc

Multi ioba.l nylon, 210, 211, 306

Natural rubbcl fibre: see Rubber(Natural) fibre

Nelson process, viscose, l8Nickel base alloy fibtes, 695Nitrocellulose, 4

f ib rcs ,5'Nomex ' ,325Nylon: Jee Polyamide fibres.

chemical modification, 307cross-linkins, 307F.T.C. defi,iition, xxvii, 209grcft polylrcrisation, 308ncw lypes, JUJnomenclature,20?physical moditication, 305

Nylon 6T, 324Nylon MXD-6, 323Nytril fibres: see Polyvinylidene

dinitrile fibres.t . , l .L . oeun luon, xxv I , JzJ

Okonratic proccss; 20Olcfin, F.T.C. dcfinit ion, xxvii,

5 4 1fibres: sce I'olyolcfin fibrcspo lymcrs ,538

Orientation, xdegree of, xveffect of, xivstretching and, xx

PCDT polyester fibrcs: see Poly-ester (poly-l, 4-cyclohcxylcrc-dirncthylcnc tcrcphthahtc;PCDT) fibrcs.

Peanut l ibres: Jce Oroundnutprotcin fibrcs.'Pcr lon 'L ,208

'Pcrlon' U, 6ll

PDT polycstcr f ibrcs;scc I 'oly-cstct (polyc(hYlcnc tcrcPhthll 'latc) f ibrcs.

PolyacryloDitri lc f ibrcs: scc I 'oly-acrylonitri lc (acrylic) rndPolyacrylonitri lc (nrodacrylic)fibrcs.

in t roduc t ion ,393nourcnclaturc, 396t y p c s , 3 9 5

Polyacrylonitri lc (acrylic) t ihrcs,398

Polyrcrylonitri le (ntodncrylic)fibrcs, 426

Polyanlidc fibrcs: scc Polyalnidc(nylon 3) f ibrcs, ctc.

a romat ic ,323conrparisol of 6 and 6.6, 203c las t ic ,612introduction, 194ncw typcs, 303nonrcnclaturc,20Tt v n c s . 2 0 9

I'oiyarrrir lc (nylon l) t ihrcs, 3 l0Polyanridc (nylon 4) t ibrcs, 310Po lyanr idc (ny lon 5) f ih rcs , 3 l l

, I 'olyanrldc (rrylon 6) t ibrcs, 20t,261

Polyamidc (nylon 6.6) f ibrcs,195, 209

Polyanidc (nylon 6.10) tibres,302

Polyarrridc (nylon 7) f ibrcs, 3l 3l 'olyanldc (nylorr d, l l l)rcs, J I /Polyanridc (nylon 9) f ibrcs, 319Polyanri<lc (nylon I l) f ibrcs, 292Polyanriclc (nylon l2) t ibrcs, 320I'olycarbonotc fibrcs, 714Poly-1, 4-cyclohcxylcrc{l imcthy'

lcnc tcrcphthrlatc ftbtcs: sccPolycstcr (poly-1, 4'cyclo-hcxylcrrc-dirncth)' lcnc tcrc-phthalatc: PCI)T) l ibrcs.

Polycster f ibrcs: scc lolycslcr( poly- l , 4-cyclohcxylcnc-dirrcthylcnc tcrcph thilatc iI 'Cl) f) nnd Polycstcr (noly-ctlrylc|lc lctolhthohtc;I ' l l l) l i l trcs.

l,olvcstcr f i l lrcsclicnrical rnodil ication. 39()l:, ' l ' .C'. dctinil ior, xxvii, 310in t roduc t ion ,32S

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mod i f l ca t i ons ,389new types, 391nomenc la tu re ,329physical nlodif icat ion, 389t y p c s , 3 2 8

Polycstcr (poly-1, 4-cyclohexylene-dirnethylene terephthalate;PCDT) f ibres, 376

lolyester {polyetl lylene tcreph-thalatc; PDT) f i brcs, 3 j0

I 'olyesters, dcvcloptnent of, 196P o l y c t h y l e n c , 5 3 7 , 5 4 1l 'olyethylenc f ibres, 5 36. 541Polycthylcne terephthalate fibres;

s.c Polycster (polyethylcne;PIT) f ibrcs

I 'olyisobutylcnc, 536Polyisoprere, 159Polymerization, xxiv

addit ion, xxivcondensation, txivhead and tai l , 569vrnyl conlpounds, 392

Polymer-modilied viscose ravon.3 8

Folynosic f ibres: see Viscose(high wet modulus) fibres

d e f i n i t i o n , 5 2 , 5 3Po l yo le f i n ,539Polyolef in f ibrcs, 536

in t l oduc t i on ,536nomenc la tu re ,54 lt y p c s , 5 4 l

Po l yp ropy lene ,565commercial developntent, 57 1p roduc t i on ,565steric structure, 564stcreorcgulari ty,565

Polypropylene f i bres, 564I 'olypropylcrrc spl i t f iLn hbres,

601Po lypy r ro l i donc ,3 l0Polystyrenc f ibres, 533Polytetranuoroethylcne (PTFE)

fibrcs, 509Polythene: Jee PolyethylenePo l yundecanamide ,292Polyurea librcs, 707lolyurethane (spandex) fi bres,

6 t 0Polyvaler6hslqm, 311l'olyvinyl alcohol (vinal) fibres, 493

.722

I'olyvinyl chloridc (PVC; vinyon)f i b res ,444

Polyvinyl chioride (chlodnated)f i b res ,480

Polyvinyl chloride (copolymet -'Dynel '

type) f ibres, 468Polyvinyl chloride (copolymet -

'V inyon 'H IJ t ype ) t i b r cs , 461

Polyvi yl f luoride f ibres, 520l'olyvinylidene chloride (saran)

f i b res ,484Polyvinyl idcnc dinitr i lc (nyrr i l )

f ibrcs, 523Pot spinning, viscosc, 15Propylene, polyrnerization, 565

5'17Protci l l f ibres, xi i , 7, 115

nrisccl laneous, 147nornenclatute, 116

PTI'E, Jee Polytetrafluoroethv-lene fibres

Pyrrol idone, 310

Qiana, 322Quartz fibret, 179

Radiat ion, si l ica (G) t jbrcs, 186Rayon: see Cupro, V iscose,

Saponificd Ccllulose Esterf.T.C. delinition, xxvii, 9'Refrasi l ' ,

182Ripening, viscose, l3Rubber (natural) f ibres, 153

Saponified cellulose estcr fibres.9, 74

Saran: rc? Polyvinyl idencchloride fibrcs

F.T.C. dcf init ion, xxvi i i , 485Schu tzenbe rge r ,80Schwabe, Louis. 3Seaweed, fibres fronl, 7)cf lcln, xNSilica fibres, 178Sil ica (G) f ibres, 181Sil ica (V) f ibres, 138Silicate (mineral) fibres, 176Silk protein, xivSkin effect, xx, 24Soda celh-rlose, 12

-F].HF}Hh

Sodium cel lulose xanthate, 13Soya bean protein f ibrcs, 144Spandex f lbres: Jee Polyurethane

librcsF,T.C. definit ion, xxvi i i , 615

Speakman, Prof. J. 8., 149Spinning, xvi i i , xix, l3

dry, xixman-made f ibres, xvi i inlclt, xixwct, xvi i i

Spun-dyed viscosc, 21, 29Spun yarns, xvi iStainless steel fibrcs: see IUetallic

(stainless steel; S.S.) fibresStaple yaJns, xviiStcarn, C. I I . , 9Stcreoblock polyners, 569Stereospecif ic polymerization, 569Stretching, xx, xxi

effect on orientation, xxiS t y r e n e , 5 3 3'Supcr' high lcnacity viscosc

nyon, 42Superpolyanrides, 198Superpolyesters, 197Surface-modifi cd viscose, 2lSwan, Sir Joseph, 5Syndiotactic polypropylene, 566Synthetic f ibrcs, 192

Tachikawa, S., 5l'Tcf lon', 509Telonrerization,294" f e n a s c o ' , 2 6 , 4 0

Terephthai ic acid, 332Tetraf luorocthylene, 509Thrcad-Likc molcculcs, ixToplram, C. lr . , 9Tophanr box, 9Triacctatc fibres, 99'Iiicel', 100Tyre cords, 46Tyrex lnc., 42

'Vicara', 141Vinnl: see I 'olyvi yl . lcoltol

fibrcsIr.T.C. dcfinit ion, x\vii i , 495

Vinyl acctnte, 463Vinyl alcohol, 493Vinyl chloridc, 446, 447Vinyl conrpounds, polyrncrization

of , 392Vinylidcnc chloridc, 484Vinylidcnc dinitri lc, .523Vinylon: scc lblyvinyl rlcolrol

llbrcsVinyon: sec I 'olyvinyl chloridc

fibrcsF.T.C. dcfinit ion, xxvii i , 446'V inyon ' l l l l , 463

Viscosc rayon, 9Viscosc rayon (high tcnacity), 39Viscosc rayon (high wct nlodulus;

p o l y n o s i c ) , 2 5 , 4 ?Vu lc rn iz r t io | | o f rubhcr , 154

wct spinning, xvii iWood pulp, viscose fronl, I IWool protcin, xii i

Yarnscontinuous l i lamcnt, xviispun, xviistaplc, xvii

Zein fibres, l4l

Urban, Johann,'U ry l on ' , 70?

Valerolactam,'vercl ' ,42' l

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