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BASICS OF TEXTILE MANUFACTURING

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Major Cellulose FibersBy: T. SRIVANI, Asst. Prof., DFT Dt: 28.01.10

INTRODUCTION OF TEXTILE INDUSTRY

Textile Industry in India is the second largest employment generator.Indian textile industry is the second largest in the world, second only to China. It accounts for more than 30% of the total exports. Indian textile industry is constituted of the segments like Readymade Garments, Cotton Textiles including Handlooms, Man-made Textiles, Silk Textiles, Woolen Textiles, Handicrafts, Coir, and Jute.

CELLULOSIC FIBRES

MAJOR CELLULOSIC COTTON LINEN JUTE

MINOR CELLULOSIC HEMP SISAL KAPOK RAMIE COIR PINA

COTTON THE KING OF FIBRES Cotton is a soft, staple fibre that grows around the seeds of the cottonplant (Gossypium sp.). Cotton comes from the Arabic word qutun or kutun

Cotton is cool, soft and comfortable to wear It is the principal clothing fiber of the world. Its production is one of the major factors

in world prosperity and economic stability.

IMPORTANCE OF COTTON IN TEXTILE INDUSTRY Cotton, one of the principal crops of the country, plays a key role inthe Indian economy. Cotton is also the main raw material for the huge domestic textile

industry. 4 million farmers are cultivating cotton . Area - 85 lakh hectares.

Production - 150 lakh bales.

MAJOR PRODUCERS AND SOURCES OF COTTON Cotton grows in the seed pod of a genus of plant named gossypium. Grows best in light, loamy soil. Major countries producing cotton are United States of America. China,

India, Pakistan, Egypt, Brazil. Some other suppliers : Peru, Cyprus, Central Asia, Japan, and Italy.

MAJOR COTTON PRODUCING COUNTRIES1.PEOPLES REPUBLIC OF CHINA(35.8 million pound bales)

2. 3.

INDIA(25.3 million pound bales)

UNITED STATES OF AMERICA(19.2 million pound bales)

COTTON

Cotton History backs to 3,500 BC- India 3,000 BC Peru Composed of 85-90% cellulose A seed hair grows on seed, a single cell 1 seed may have app. 2000 fibers

1 boll may have app. 100,000 fibers. Fibers accumulate moisture & salt for germination and also to protect. As the plant matures, the boll opens, fibers dry, the cell wall collapses, flattens and twists. This becomes a characteristic feature of cotton, called convolutions. They may be around 100-300 per inch,and they are responsible for cottons spinnability.

COTTON LONGITUDINALSECTION

cotton has a Bean-shaped cross section

Traditionally spun with Z-twist, as it is the direction it twists when dried. Z twist stays intact on cotton. Gossipium is the Genus. Gossipium hirsutam. Gossipium peruvianum. Gossipium arboreum. Gossipium herbaceum. Gossipium barbedense. Gossipium purpurascede.

TYPES OF COTTONThe 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

STRUCTURE OF COTTON Under a microscope, a cotton fiber appears as a very fine, regular fiber. length: 10 mm to 65 mm Diameter: 11 micron meters to 22 micron meters.

Length to breadth ratio: 6000:1 (longest) to 350:1 (shortest) Look like a twisted ribbon or a collapsed and twisted tube.

Twists are called convolutions.

Properties of cotton fibersProperty Shape Luster Tenacity (strength) Dry Wet Resiliency 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

DensityMoisture absorption raw:conditioned saturation mercerized: conditioned saturation Dimensional stability Resistance to acids alkali organic solvents sunlight microorganisms insects Thermal reactions to heat to flame

1.54/1.56 g/ccm8.5% 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.

IDENTIFICATION OF COTTON FIBRETest Soda ash 40% sol. Causti c soda 25% sol. Sodi um hypo chlo ride Hyd ro chlo ric acid 40% Turn s yello wish Nitr ic acid 15% Nitric acid 70% Sulp huric acid 15% Sulp huric acid 70% Burning in Flame Microsc opic View Remarks

Fiber Cotto n swells Swells & Shines Whit ened Ope ns up looses strengt h Dissol ves slowly Disso lves on heat ing Disso lves quick ly Burns continuo usly leaving grey ash of burning paper smell Longitud inal twists. Resistanc e to alkalis.

VARIOUS FINISHES APPLIED ON 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 shape-retension and imparts dip-dry characteristic Schrenerizing-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

USES OF COTTON In apparels- men, women and children wear In household furnishings In industrial textiles In medical field In hosiery and sportswear In tents and shelters

ADVANTAGES It can be processed into a wide selection of fabrics1. Sheer fabrics- cambric,batist chiffon,lawn,organdy and voile. 2. Medium weight cottons-broadcloth,drill,flannel,poplin,terry cloth and long cloth. 3. Heavy weight cottons-brocade,corduroy,denim,pique and velveteen Can be mercerized to improve luster, absorbency,dyeability and strength. Textured effects are easily achieved by1. Changing yarn structure-high twist yarns, nub yarns, boucl yarns, crimped yarn 2. Changing fabric construction- crepes, seer suckers 3. Application of special finishes- embossing and napping Can be easily dyed or printed with almost all classes of dyes. Good absorbency, Does not build up static electricity, Good conductor of heat

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

Staple Yarn manufacturing The concept Making all the fibers to be parallel to each other and twist so as the fibers wrap around each other.

Cotton Process Plucking and Picking Ginning Opening and mixing Cleaning Carding Drawing Combing(optional) Roving Spinning

Yarn Manufacturing ProcessesPlucking:1. Manual 2. 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 done with the help of mechanical beaters Since bales are of different density, they are cut 24 hrs before processing in order to allow them to bloom.

Scutching

The opened bunch of fibers are picked and opened Further cleaned off the dirt, sand, broken stalks and leaves, seeds etc., The fibers are oriented towards their length Finally a web like finely oriented lap is drawn over a roller called Lap roller

Carding

The lap is fed between two rollers of combs of fine needles, directionally operating opposite, comb the lap. Another doffing comb cleans and orients the fibers apart by removing short fibers,dirt and other impurities. The lap is transformed into a voluminous soft strand called card sliver.

Carding

The 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.

Drawing A set of card slivers are placed and drawn together to produce Same length of Sliver equal to set of the slivers fed. The short staples are removed and the fibers are more paralelalised and the fibers from different lots are more evenly mixed towards the twisting axis.

Combing This process is similar to drawing but having very fine needles as combers The shorter fibers are more effectively removed, more oriented so that it could be spun into a more finer and superior quality yarn. Combing is generally an optional process which is done generally for finer quality of yarns.

CombingProvides more extensive cleaning than cardingRemoves short fibres (linters) neps and trash so that the resulting sliver is Clean, lustrous and more uniform in diameter.

Roving The slivers from drawing are drawn further to a finer strand with lesser twist just to hold the fibers This results in roved sliver

Spinning Th

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