cellulosic fibres

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CELLULOSIC FIBRES

FIBRE:-Fiber or fibre is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. Natural fibersVegetable fibre Animal fibre Mineral fibre

Man-made fibers

May come from natural synthetic chemicals

CELLULOSIC FIBRES

NATURAL CELLULOSIC COTTON LINEN JUTE HEMP SISAL KAPOK RAMIE COIR PINA

MANMADE CELLULOSIC RAYON ACETATE TRI ACETATE Cupra Ammonium

COTTON

Properties of cotton fibersProperty Shape Luster Tenacity (strength) Dry Wet Resiliency Density Moisture absorption raw:conditioned saturation mercerized: conditioned saturation Dimensional stability Resistance to acids alkali organic solvents sunlight microorganisms insects Thermal reactions to heat to flame Evaluation Fairly uniform in width, 12-20 microns; length varies from to 2 inches; typical length is to 1 inches. low 3.0-5.0 g/d 3.3-6.0 g/d low 1.54/1.56 g/ccm

8.5% 15-25% 8.5-10.3% 15-27%+ good

damage, weaken fibers resistant; no harmful effects high resistance to most Prolonged exposure weakens fibers. Mildew and rot-producing bacteria damage fibers. Silverfish damage fibers.

Decomposes after prolonged exposure to temperatures of 150C or over. Burns readily.

The following species are grown commercially: Gossypium arboreum L. Tree cotton, native to India and Pakistan. Gossypium barbadense L. known as American Pima, Creole, Egyptian, or Sea island cotton, native to tropical South America. Gossypium herbaceum L. Levant cotton, native to southern Africa and Arabian Peninsula. Gossypium hirsutum L. Upland cotton, native to Central America, Mexico, the Caribbean and southern Florida - most commonly grown species in the world. Gossypium peruvianium Gossypium purpurascade

TYPES OF COTTON

COTTON LONGITUDINALSECTION

Also cotton has a Bean-shaped cross section

Yarn Manufacturing ProcessesPlucking:2. Manual 3. Mechanical Picking:- open tufts are collected and rolled into a batt. Then batt is removed from the cylindrical screens of the picker in an even flat sheet and rolled into a lap

GinningHarvested raw cotton Contains seeds, leaf fragments etc. Cottonseeds weigh 2/3rds of raw cotton when picked. These are removed by a cotton gin. Cotton gin has saw-toothed bands that pull the fiber from the seeds. Then cotton fiber is compressed into rectangular bales, covered with jute or polypropylene bagging and bound with iron bands.

Opening and blending

The sequential production process begins by converting the compacted layers of baled cotton into small, light, fluffy tufts that facilitate removal of foreign matter. This initial process is called opening. Since bales are of different density, they are cut 24 hrs before processing in order to allow them to bloom.

Scutching

It refers to the blow room operations. The resultant is a cotton lap

CardingThe card successively works on small tufts of fibres separating or opening them ,removing a high percentage of trash and other foreign matters collecting the fibre in a rope-like form called sliver and delivering it for further processing. The fibres are made parallel to each other and their direction is oriented.

Combing

Provides more extensive cleaning than carding Removes short fibres neps and trash so that the resulting sliver is clean and lustrous.

Drawing and roving first or initial twist to the yarn is given. Its diameter is 2mm -3mm Spinning-production of yarn by twisting the yarn. Its of 2 types Open-end spinning Close-end spinning Doubling- each yarn has two single yarns, to make it stronger Sizing, Gassing- done to give uniformity to the yarn

4. 5.

VARIOUS FINISHES OF COTTON

Mercerization- adds strength, improves lustre, absorbency, dyeability Sanforization-ensures less than 1 % shrinkage Moireing- for variable luster and variable pattern Glazing-gloss, smoothness and embossed effects Stiffening- smoothen, stiffens and strengthens Wrinkle resistant permanent press- improves shaperetension and imparts dip-dry characteristic Schreinerizing-adds luster

Stain repelling-for easy care Napping-for softness, warmth and increased absorbency Singeing-for smoothness Weighting-for bulk Insulating-for warmth Embossing-for decoration Mildew resistant Fire-retardant Moth-resistant

ADVANTAGES 2. 3. 4.

It can be processed into a wide selection of fabricsSheer fabrics- cambric,batist chiffon,lawn,organdy and voile. Medium weight cottonsbroadcloth,drill,flannel,poplin,terry cloth and long cloth. Heavy weight cottons-brocade,corduroy,denim,pique and velveteen Can be mercerized to improve luster, absorbency,dyeability and strength. Textured effects are easily achieved byChanging yarn structure-high twist yarns,nub yarns, boucl yarns, crimped yarn Changing fabric construction- crepes,serersuckers Application of special finishes- embossing and napping Can be easily dyed or printed with almost all classes of dyes. Good absorbent, Does not build up static electricity, Good conductor of heat

9. 10. 11.

Limitations

Untreated cotton wrinkles easily Susceptible to mildew if left damp Flammable Takes a long time to dry

SISALThe sisal plant has a 7-10 year life-span and typically produces 200-250 commercially usable leaves. Each leaf contains an average of around 1000 fibers. It is extracted by a process known as decortication.

USESSisal is used in three grades: 3. The lower grade fiber is processed by the paper industry because of its high content of cellulose and hemicelluloses. 5. The medium grade fiber is used in the cordage industry for making: ropes, baler and binders twine 7. The higher-grade fiber after treatment is converted into yarns

LINENLinen or flax fibres are extracted from the stem or bast of flax plant Fibres held together by gummy substance called as Pectin Flax fibre basically composed of Cellulose

QUALITY AND GRADES Countries cultivating flax plant areBelgium Scot France Russia Germany

Countrai flax produces the finest and strongest yarn from Belgium

METHODS OF SEPARATION OF LINEN 4.

CULTIVATION: April or May HARVESTING: By the end of August PREPARATION OF FIBRES:

Rippling/Threshing seeds and leaves removal from stem. Retting Most important process where stems are left under moistened condition to decompose and separation of fibers.

Types of retting :1. 2. 3. 4. 5.

Dew retting Pool or Dam retting Stream retting Vat retting Chemical retting Breaking Scutching Hackling (Coming) Spinning.

4. Manufacturing process:

CONSTRUCTION OF LINEN FABRICS

Inelastic so usually break during weaving process Very moist atmosphere is required. Generally not knitted because of a) Inherent stiffness b)Resistance to being formed

into

SO, usually blended with cotton or other man made fibres

END PRODUCTS OF LINEN FARICS

Apparel fabrics shirt, skirt,jackets etc. Accessories fabric- pockets,bags etc. House hold textiles- bed n table clothing etc. Industrial textiles- tarpaulins, ropes etc

It is very durable, two or three times stronger then cotton. High absobency,smoothness so comfortable to wear. Good resistance to alkalies and bleaches. Easily dyed and printed. Withstand high ironing temperature.

Linen wrinkles easily. Lacks flex abrasion n hence shows wear on crease lines n seams Fabrics take long time to dry. It is imflammable. Susceptible to mildew if left damp. It has poor press-crease retention.

JuteSOURCEJute is one of the strongest natural fibres The jute fibre comes from the stem and ribbon (outer skin) of the jute plant. The production is concentrated in Bangladesh, India, China, and Thailand. It is the second most important vegetable fibre after cotton, in terms of usage, global consumption, production, and availability. It is the second most important vegetable fibre after cotton, in terms of usage, global consumption, production, and availability

MANUFACTURING PROCESSThe fibres are first extracted by retting. The retting process consists of bundling jute stems together and immersing them in low, running water.

There are two types of retting: stem and ribbon. After the retting process, stripping begins. In the stripping process, nonfibrous matter is scraped off, then the workers dig in and grab the fibres from within the jute stem.

PROPERTIES

Jute fibre is 100% bio-degradable and recyclable and thus environmentally friendly. It is a natural fibre with golden and silky shine and hence called The Golden Fibre. It is the cheapest vegetable fibre procured from the bast or skin of the plant's stem. It has high tensile strength, low extensibility, and ensures better breathability of fabrics.

ADVANTAGES

good insulating and antistatic properties low thermal conductivity moderate moisture regain. acoustic insulating properties no skin irritations.

DISADVANTAGES

poor drapability Brittleness fibre shedding yellowing in sunlight Jute has a decreased strength when wet

USESIt is used as substitute for hemp As binding thread for carpet and rugs, rug cushions, filler with other fibers. As a linoleum base Made into cheap coarse fabrics Heavy bagging.

JUTE MATS

COIR

SOURCE Coir fibers are found between the husk and the outer shell of a coconut. The individual fiber cells are narrow and hollow, with thick walls made of cellulose. The coir is of two types: 7. Brown coir 8. White coir

MANUFACTURING PROCESSBROWN COIRBrown coir is harvested from fully ripened coconuts The fibrous layer of the fruit is then separated from the hard shell (manually) by driving the fruit down onto a spike to split it (De-husking The fibrous husks are soak

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