fibres n yarn

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FFFiiibbbrrreeesss aaannnddd YYYaaarrrnnnsssFabric Knowledge

under the guidance of

Mr.Dibyendu Bikash Dutta

SUBMITED BY:

KARISHMA YADAV

MFM-2011-13

ROLL NO.35


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Fibres and Yarns 2

TABLE OF CONTENT

S.No. TOPICS

1. Fibres.2

Classification of fibres3-6

2. Silk.7-11

Manufacturing process

Properties

End uses of silk

3. Cotton..12-15

4. Jute.16-20

5. Rayon..21-27

6. Spandex28-32

7. Yarns..33-35Simple and decorative yarns.36-38


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Fibres and Yarns 3

Fibres

A fibre is a hair like strand from which all fabrics are made.

Fiber or fibre is classes of materials that are continuous filaments or are indiscrete elongated pieces, similar to lengths of thread.They are veryimportant in the biology of both plants and animals, for holding tissuestogether. Human uses for fibers are diverse. They can be spun into filaments,string or rope, used as a component of composite materials or matted intosheets to make products such as paper or felt.


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Fibres and Yarns 4

CLASSIFICATION OF FIBRES

Short fibres: staple fibres

Long fibres: filament fibres

Fibres can also be classified on basis of origin

Natural Fibres

silk

cotton

wool

jute

Man-Made Fibres

Nylon

Polyester

Rayon

Spanex

Natural Fibres :

these are the fibres obtained from naural sources such as plants and animals

These fibres are obtained from different plants. Some are well known and useful to

man. Cotton can you think of any such fibre? That is right, cotton, jute and coir.

Cotton is obtained from seed of the plant, jute is obtained from the stem of a plant and

coir is the outer covering of coconut.

Animal Fibres

These fibres are obtained from different animal sources. Can you name the fibre weget from sheep and goat? Thats right, we get wool from their hair. Wool can also be

obtained from the hair of rabbits and camels.

Another animal fibre you all are familiar with is silk. It is the secretion of an insect

called the silk worm.

Example : cotton , slik, jute, wool

Man-Made Fibres :

these are the fibres obtained from chemical substances

When you go to the market to buy fabrics, you must have heard from the shopkeeper

that it is a synthetic material. Dont get disturbed. Synthetic is another name for man-

made fabrics. The first man-made fibre is known as rayon and was produced in the

latter part of 19th century.

Example : Rayon , Polyester, Nylon, Spamdex


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Fibres and Yarns 5

Fibres

on basisof Length

Staple Filament

on basisof Origin

Animalsvegetable

NaturalMan-Made


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Fibres and Yarns 6

SILK

Silk fibers are smooth, translucent, rod-like filaments with occasional swellings alongtheir length. The raw silk fiber actually consists of two filaments called fibroin boundby a soluble silk gum called sericin. Fibroin and sericin are made up of carbon,hydrogen, nitrogen, and oxygen.

Silk has several important qualities:

(1) It is lower indensitythan wool,cotton, or rayon.

(2) It is a poor conductor of heat andelectricity.

(3) It is capable of soaking up to 30% of its weight in moisture.

(4) It is extremely strong, with a breaking strength as high as 65,000 psi.

(5) It will stretch to as much as 20% of its length without breaking.

(6) It is thermally stable; it is able to withstand temperatures as high as 284F(140C).

(7) It becomes smooth, lustrous, and luxurious when processed.

(8) It is remarkably resilient, and shows excellent wrinkle recovery.
http://science.jrank.org/pages/1994/Density.htmlhttp://science.jrank.org/pages/1994/Density.htmlhttp://science.jrank.org/pages/1994/Density.htmlhttp://science.jrank.org/pages/1833/Cotton.htmlhttp://science.jrank.org/pages/1833/Cotton.htmlhttp://science.jrank.org/pages/1833/Cotton.htmlhttp://science.jrank.org/pages/2342/Electricity.htmlhttp://science.jrank.org/pages/2342/Electricity.htmlhttp://science.jrank.org/pages/2342/Electricity.htmlhttp://science.jrank.org/pages/2342/Electricity.htmlhttp://science.jrank.org/pages/1833/Cotton.htmlhttp://science.jrank.org/pages/1994/Density.html


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Fibres and Yarns 7

MANUFACTURING PROCESS

The natural habitat for a silk worm is the mulberry tree, which is cultivated in large

amount for the breeding of the silk worm. The traditional silk production process is

also known as sericulture. Following steps are involved in silk fiber production

process:

1- Hatching of Eggs

First of all, silk moth lays eggs and when the eggs get hatched, caterpillars feed

mulberry leaves. Further, when the silkworms are about 35 days old they are much

heavier, than when they hatched. Finally, now they are now ready to spin a silk

cocoon.

2- Silk production by worm

The silk is actually produced in two glands, in the silkworms head, and the liquid is

also formed, in the openings called spinnerets. The silk gets solidify when it comes in

contact with the natural air. Further, silkworm spins approximately one mile of

filament and completely encloses itself in a cocoon for about 2 or three days.

3- Transition of the worm

The silkworm then passes through various other stages and changes into a moth.

But, the silkworm is usually killed using heat before it reaches this particular stage.

The silkworms are killed for the reason that, if once they reach the moth stage, moth

secretes a fluid to dissolve the silk so it can emerge from the cocoon. This is

because cocoon gets damaged and in turn lowers the quality of silk.

4- Raw Fiber Obtained

Then further, silk is extracted from the undamaged cocoons by brushing the cocoon

to find the outside ends of the filament. The silk filaments are then wound on a reel.

One cocoon contains roughly 1,000 yards of silk filament. The silk prepared at this

stage is known as raw silk. A yarn can now be produced by combining several other

filaments of silk.

Production of silk is considered one of the time consuming and labour intensive

practice.


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PROPERTIES

PHYSICAL CHEMICAL*Silk is one of the strongest naturalfibers but loses up to 20% of itsstrength when wet.

Silk emitted by the silkwormconsists of two main proteins,sericinandfibroin, fibroin being thestructural center of the silk, andserecin being the sticky materialsurrounding i

Silk fibers from the Bombyx morisilkworm have atriangularcrosssectionwith rounded corners, 5-10

mwide

The high proportion (50%) ofglycine, which is a smallaminoacid, allows tight packing and the

fibers are strong and resistant tobreaking.

. Silk has a smooth, soft texturethat is not slippery, unlike manysynthetic fibers.

The tensile strength is due to themany interseeded hydrogenbonds, and when stretched theforce is applied to these numerousbonds and they do not break.

Silk is one of the strongest natural

fibers but loses up to 20% of itsstrength when wet.

Silk is resistant to mostmineral

acids, except forsulfuric acid,which dissolves it

It has a goodmoisture regainof11%.

It is yellowed by perspiration.

Silk is a poor conductor ofelectricityand thus susceptible to

static cling.
http://en.wikipedia.org/wiki/Sericinhttp://en.wikipedia.org/wiki/Sericinhttp://en.wikipedia.org/wiki/Fibroinhttp://en.wikipedia.org/wiki/Fibroinhttp://en.wikipedia.org/wiki/Fibroinhttp://en.wikipedia.org/wiki/Trianglehttp://en.wikipedia.org/wiki/Trianglehttp://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/%CE%9Cmhttp://en.wikipedia.org/wiki/%CE%9Cmhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Synthetic_fiberhttp://en.wikipedia.org/wiki/Synthetic_fiberhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Static_clinghttp://en.wikipedia.org/wiki/Static_clinghttp://en.wikipedia.org/wiki/Static_clinghttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Mineral_acidhttp://en.wikipedia.org/wiki/Synthetic_fiberhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/%CE%9Cmhttp://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/Cross_section_(geometry)http://en.wikipedia.org/wiki/Trianglehttp://en.wikipedia.org/wiki/Fibroinhttp://en.wikipedia.org/wiki/Sericin


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END USES OF SILK

The ready-to-wear sector is also a large user of silk,especially in the luxe category.

silk shirts, silk pyjamas, dressing gowns.

Silk laces and tulles:Are unbeatable for theirlightness and are frequently used for bridal veils and

dresses.

Knitting:Silk-knitting is a very important activitywhich produces a very wide range of clothingarticles. Knitting gives hosiery items that ideal

elasticity and that plastic character which no other

article can rival. Scarves and squares: Permanent components of

womens and mens wear, they are also highly

appreciated as gifts

Ties:

For the man who is anxious to look well-dressed, the silk tie is must. It also makes a very

welcome present.

Passementerie: Is the name given to all thetechniques connected with the production of

decorative articles such as ribbons, braids,

pompoms, tassels, etc. used both in clothing and in

furnishing.

Furnishing and upholstery:As far as art isconcerned, furnishing and upholstery have been one

of the chief outlets for silk for centuries.

Sewing-thread: Essential for sewing qualitygarments.

Ribbons: Ribbons for typewriters, computers, cash-registers, etc. are often made of silk.

Insulation: Silk is often used as an insulator in

sophisticated devices such as space vessels.


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Fibres and Yarns 11

COTTON

Cotton, as a natural cellulosic fiber, has a lot of characteristics,

such as;

Comfortable Soft hand

Good absorbency

Color retention

Prints well

Machine-washable

Dry-cleanable

Good strength

Drapes well

Easy to handle and sew


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Fibres and Yarns 12


Opening and Cleaning

Conversion of fibers into a bat, weighing 10-30 ounces/sq.yard, by Needle punching or Air-lay technique.

Scouring

Bleaching

Finishing

Washing

Drying

Fiber opening


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PROPERTIES

PHYSICAL CHEMICALFibre LengthFiber length is described [7] as "the average

length of the longer one-half of the fibers

(upper half mean length)" This measure is

taken by scanning a "beard " of parallel fibers

through a sensing region. The beard is formed

from the fibers taken from the sample,

clasped in a holding clamp and combed to

align the fibers. Typical lengths of Upland

cottons might range from 0.79 to 1.36in.

Cotton swells in a high humidity

environment, in water and in concentrated

solutions of certain acids, salts and bases.

The moisture regain for cotton is about

7.1~8.5% and the moisture absorption is

7~8%. [20]

Cotton is attacked by hot dilute or cold

concentrated acid solutions. Acid

hydrolysis of cellulose produces hydro-

celluloses. Cold weak acids do not affect

it.The fibers show excellent resistance to

alkalis. There are a few other solvents that

will dissolve cotton completely.

Cotton degradation is usually attributed to

oxidation, hydrolysis or both.


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END USES

The major end uses for cotton fibre include wearing apparel, home

furnishings, and other industrial uses (such as medical supplies).

The cotton fibre is made primarily into yearns and threads for use in thetextile and apparel sectors (wearing apparel would account for

approximately 60% of cotton consumption).

Cotton is also used to make home furnishings, such as draperies (eventually

the third major end use) or professional garments (about 5% of cotton fibre

deman

Apparel - Wide range of wearing apparel: blouses, shirts, dresses,

childrenswear, active wear, separates, swimwear, suits, jackets, skirts, pants,

sweaters, hosiery, neckwear.

Home Fashion - curtains, draperies, bedspreads, comforters, throws, sheets,

towels, table cloths, table mats, napkins

Cotton fabrics with specialty applications include, for example, fire-proof

(flame resistant) apparel, which is suitable for professional uses and provides

effective protection against potential risks associated with high temperature

and particularly flashover.

Flame resistant cotton fabrics are treated with chemicals.


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JUTE

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 is the second most important vegetable fibre after cotton, in terms of

usage, global consumption, production, and availability.

It has high tensile strength, lowextensibility, and ensures better

breathabilityof fabrics. Therefore, jute is very suitable in

agricultural commodity bulk packaging.

It helps to make best quality industrial yarn, fabric, net, and sacks. It is

one of the most versatile natural fibres that has been used in raw

materials for packaging, textiles, non-textile, construction, and

agricultural sectors. Bulking ofyarnresults in a reduced breakingtenacity and an increased breaking extensibility when blended as

a ternary blend.

The best source of jute in the world is the Bengal Delta Plain in

theGanges Delta, most of which is occupied by Bangladesh.

Advantages of jute include good insulating andantistaticproperties, aswell as having lowthermal conductivityand a moderatemoisture regain.Other advantages of jute includeacoustic insulatingproperties andmanufacture with noskin irritations.
http://en.wikipedia.org/wiki/Extensibilityhttp://en.wikipedia.org/wiki/Extensibilityhttp://en.wikipedia.org/wiki/Extensibilityhttp://en.wikipedia.org/wiki/Waterproof_fabrichttp://en.wikipedia.org/wiki/Waterproof_fabrichttp://en.wikipedia.org/wiki/Yarnhttp://en.wikipedia.org/wiki/Yarnhttp://en.wikipedia.org/wiki/Yarnhttp://en.wikipedia.org/wiki/Static_electricityhttp://en.wikipedia.org/wiki/Static_electricityhttp://en.wikipedia.org/wiki/Static_electricityhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/wiki/Soundproofinghttp://en.wikipedia.org/wiki/Soundproofinghttp://en.wikipedia.org/wiki/Soundproofinghttp://en.wikipedia.org/wiki/Irritationhttp://en.wikipedia.org/wiki/Irritationhttp://en.wikipedia.org/wiki/Irritationhttp://en.wikipedia.org/wiki/Irritationhttp://en.wikipedia.org/wiki/Soundproofinghttp://en.wikipedia.org/w/index.php?title=Moisture_regain&action=edit&redlink=1http://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Static_electricityhttp://en.wikipedia.org/wiki/Yarnhttp://en.wikipedia.org/wiki/Waterproof_fabrichttp://en.wikipedia.org/wiki/Extensibility


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Land Preparation

The first step of Jute cultivation is land preparation. The land

preparation is completed at between January to March of a

year. Land preparation for the jute also depend on the types of

Land, Weather and the kind of water.

Seeds Sown

The time of jute seeds sowing is February to March. Basically

10 to 12 pound per acore seeds is sowed.

Plants Grow

After sowing the seeds the jute plants take time to grow and

eventually it is seen that, jute is growing rapidly.

Weeding & Thinning

When it is seen that, the plants are being surrounded by the

weeds, then an attempt is taken to wiped out all of the weeds

to thinning the lands.

Harvesting

When the jute plants got bigger and the jute fruits seem like

ripen than jute plant is to be harvested. Generally the

harvesting time continues from June to September.

Retting


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Fibres and Yarns 17

In this stage the Jute plants is to be submerged into the water

for 3 to 4 weeks.

Stripping

After retting when the jute fiber seems to be detached from

the body of jute plant, then the jute fiber is stripped.

Washing

After stripping it is recommended to wash the fiber in fresh

water. It is necessary to make the jute fiber more brighter and

clean.

Drying

After washing, drying process is started. Generally the Sun is

used to dry the jute fibers.

After drying which fiber we will get it is calledJute Fiberand

it is ready to use then.


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Fibres and Yarns 18

PROPERTIES

PHYSICAL PROPERTIES CHEMICAL PROPERTIES

Ultimate Jute Length: 1.5 to 4mm.

Cellulose > 65%

Ultimate Diameter of Jute:0.015 to 0.002 mm

Hemi-cellulose > 22.5%

Jute Color: Jute fiber can be

White, Yellow, Brown or

Grey.

Lignin > 11%

Strength of Jute: 3.5 to 5

G/Den.Specific Gravity: 1.48

Fat and Wax > 0.3%

Elasticity: Breaking Extension1.8% and Elastic Recovery verylow.

Water Soluble Materials > 1.2%

Moisture Regain of Jute: 13.75% (Standard).

Dimensional Stability of Jute:Good on average.


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END USES OF JUTE

It is used to make cloth for wrapping bales of raw cotton & to makesacks for packaging goods. used to make cloth for wrapping bales of

raw cotton & to make sacks for packaging goods. Jute Geotextile is used for preventing soil erosion, while natural

vegetation becomes established, seed protection, weed control etc.

Food Grade Jute bags are used for packaging of Cocoa, Coffee &shelled nuts, as per international specification, IJO standard 98/01.

Jute composites are used for automobile interior production. Flame proof & mild deed proof fabric using jute yarn as core & high

performance fibre as core sheath are used in Protech application, eg

Personal & property protection. Canvas cloth & Tarpaulin are used in Agrotech & Oekotech application.

Home Textile: Pep up the Living room or office rooms with bright jutecushion covers and an amazing range of jute furnishing for the sofas &

curtains. Add a dash of colour to table settings with vibrant jute mats &

other accessories. Dress up the walls with delicately embroidered jute

wall hanging.

Floor Dcor : Jute & jute blended floor coverings with ruffed textures,earthly tones or bright exotic designs makes home & workplace a truedelight . The machine made or hand knotted carpets, rugs & dhurries are

environment friendly, light weight and easy to lay and use. Hand Bags & Shopping Bags : While one enjoy the novelty and

different ranges of Jute Hand bags, one can also feel 2000 about using

an environment-friendly product, for corporate image. The range also

includes luggage, wallets and fashion bags. Novelties & Gifts : Jute novelties are as varied as it can be from tea

coaster, string bags, purses, water bottle/wine bags, hanging chairs etc.

Jute Gift item include jute doll are free from hazards, jute ornaments,

jute pencil stand for your esteemed client with a jute calendar. Gift

items of jute are not just different, they are distinct - they make a better

world.


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Fibres and Yarns 20

RAYON

There are two main categories of man-made fibers: those that are made from

natural products (cellulosic fibers) and those that are synthesized solely from

chemical compounds (noncellulosic polymer fibers). Rayon is a natural-based

material that is made from the cellulose of wood pulp or cotton. This natural

base gives it many of the characteristics

low cost, diversity, and comfort

that have led to its popularity and success. Today, rayon is considered to be

one of the most versatile and economic fibre.


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Fibres and Yarns 21

PROPERTIES

PHYSICAL CHEMICAL

Microscopic appearance

Striations seen in viscose and high

strength rayon

If delustered , scattered specks of

pigment can beseenFibers with thickness of 1.7 to 5.0dtex,

particularly those between 1.7 and 3.3 dtex,

dominate large scale production.

Hot dilute acids attack rayon, whereas

bases do not seem to significantly attack

rayon.

Tenacity ranges between 2.0 to 2.6 g/den

when dry and 1.0 to 1.5 g/den when wet.

Rayon is attacked by bleaches at very high

concentrations and by mildew under severe

hot and moist conditions.

Wet strength of the fiber is of importance

during its manufacturing and also in

subsequent usage. Modifications in the

production process have led to the problem

of low wet strength being overcome.

Prolonged exposure to sunlight causes loss

of strength because of


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Fibres and Yarns 22

Dry and wet tenacies extend over a range

depending on the degree of polymerization

and crystallinity. The higher the

crystallinity and orientation of rayon, the

lower is the drop in tenacity upon wetting.

Percentage elongation-at-break seems to

vary from 10 to 30 % dry and 15 to 40 %

wet. Elongation-at-break is seen to decrease

with an increase in the degree of

crystallinity and orientation of rayon

Abrasion resistance is fair and rayon resists

pill formation. Rayon has both poor crease

recovery and crease retention.

The ManufacturingProcessWhile there are many variations in the manufacturing process that exploit the

versatility of the fiber, the following is a description of the procedure that is used in

making regular or viscose rayon.

Regardless of whether wood pulp or cotton linters are used, the basic raw material for

making rayon must be processed in order to extract and purify the cellulose. The

resulting sheets of white, purified cellulose are then treated to form regenerated

cellulose filaments. In turn, these filaments are spun into yarns and eventually made

into the desired fabric.


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Fibres and Yarns 23

Processing purified cellulose

1 Sheets of purified cellulose are steeped in sodium hydroxide (caustic soda), which

produces sheets of alkali cellulose. These sheets are dried, shredded into

crumbs, and then aged in metal containers for 2 to 3 days. The temperature

and humidity in the metal containers are carefully controlled.

2 After ageing, the crumbs are combined and churned with liquid carbon disulfide,

which turns the mix into orange-colored crumbs known as sodium cellulose

xanthate. The cellulose xanthate is bathed in caustic soda, resulting in a

viscose solution that looks and feels much like honey. Any dyes or

delusterants in the design are then added. The syrupy solution is filtered for

impurities and stored in vats to age, this time between 4 and 5 days.

Producing filaments


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Fibres and Yarns 24

3 The viscose solution is next turned into strings of fibers. This is done by forcing

the liquid through a spinneret, which works like a shower-head, into an acid

bath. If staple fiber is to be produced, a large spinneret with large holes is

used. If filament fiber is being produced, then a spinneret with smaller holes

is used. In the acid bath, the acid coagulates and solidifies the filaments, now

known as regenerated cellulose filaments.

Spinning

4 After being bathed in acid, the filaments are ready to be spun into yarn.

Depending on the type of yarn desired, several spinning methods can be used,

including Pot Spinning, Spool Spinning, and Continuous Spinning. In Pot

Spinning, the filaments are first stretched under controlled tension onto a

series of offsetting rollers called godet wheels. This stretching reduces the

diameter of the filaments and makes them more uniform in size, and it also

gives the filaments more strength. The filaments are then put into a rapidly

spinning cylinder called a Topham Box, resulting in a cake-like strings that

stick to the sides of the Topham Box. The strings are then washed, bleached,

rinsed, dried, and wound on cones or spools. Spool Spinning is very similar to

Pot Spinning. The filaments are passed through rollers and wound on spools,

where they are washed, bleached, rinsed, dried, and wound again on spools or

cones.In Continuous Spinning, the filaments are washed, bleached, dried,twisted, and wound at the same time that they are stretched over godet

wheels.

5 Once the fibers are sufficiently cured, they are ready for post-treatment chemicals

and the various weaving processes necessary to produce the fabric. The

resulting fabric can then be given any of a number of finishing treatments.


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Fibres and Yarns 25

These include calendaring, to control smoothness; fire resistance; pre-

shrinking; water resistance; and wrinkle resistance.

High-Wet-Modulus Rayon

Manufacture

The process for manufacturing high-wet-modulus rayon is similar to that used for

making regular rayon, with a few exceptions. First, in step #1 above, when the

purified cellulose sheets are bathed in a caustic soda solution,

After the syrupy viscose solution is prepared, it is forced through a spinneret into an

acid bath. The resulting strings or filaments are then stretched on godet wheels to

strengthen them and put into a spinning Topham box. This method produces cake-

like strings of rayon, which are washed, rinsed, and dried before being wound on

spools or cones.

a weaker caustic soda is used when making HWM rayon. Second, neither the alkali

crumbs (#1 above) nor the viscose solution (step #2) is aged in the HWM process.

Third, when making HWM rayon, the filaments are stretched to a greater degree than

when making regular rayon.


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Fibres and Yarns 26

END USES

Rayon's versatility and color range long have made it a popular fiber in

apparel and home furnishings. Ultra-fine rayon gives blouses and dresses a silkier look and feel.

High-wet modulus rayon, used alone or in blends, produces apparel fabricsthat are wrinkle and shrink-resistant.

They hold color well and can be washed rather than dry-cleaned.

Rayon filament is used in tire cord, fiber deniers, suit linings, and jewelboxes.

Flame-resistant rayon/wool blends are used in commercial airline seats.


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Fibres and Yarns 27

SPANDEX

Spandex is a lightweight, synthetic fiber that is used to make stretchable clothing

such as sportswear. It is made up of a long chain polymer called polyurethane, which

is produced by reacting a polyester with a diisocyanate. The polymer is converted into

a fiber using a dry spinning technique.

Although the market for spandex remains relatively small compared to other fibers

such as cotton or nylon, new applications for spandex are continually being

discovered.

These fibers are superior to rubber because they are stronger, lighter, and more

versatile. In fact, spandex fibers can be stretched to almost 500% of their length.

The ManufacturingProcessSpandex fibers are produced in four different ways including melt extrusion,

reaction spinning, solution dry spinning, and solution wet spinning. Each of

these methods involve the initial step of reacting monomers to produce a

prepolymer. Then the prepolymer is reacted further, in various ways, and


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Fibres and Yarns 28

drawn out to produce a long fiber. Since solution dry spinning is used to

produce over 90% of the world's spandex fibers, it is described.

Polymer reactions

1 The first step in the production of spandex is the production of the

prepolymer. This is done by mixing a macroglycol with a diisocyanate

monomer. The compounds are mixed in a reaction vessel and under the

right conditions they react to form a prepolymer. Since the ratio of the

component materials produces fibers with varying characteristics, it is

strictly controlled. A typical ratio of glycol to diisocyanate may be 1:2.

2 In dry spinning fiber production, the prepolymer is further reacted with

an equal amount of diamine. This is known as a chain extension

reaction. The resulting solution is diluted with a solvent to produce the

spinning solution. The solvent helps make the solution thinner and

more easily handled. It can then be pumped into the fiber production

cell.

Producing the fibers

3 The spinning solution is pumped into a cylindrical spinning cell where it is

cured and converted into fibers. In this cell, the polymer solution is

forced through a metal plate, called a spinneret, which has small holes

throughout. This causes the solution to be aligned in strands of liquid

polymer. As the strands pass through the cell, they are heated in the

presence of a nitrogen and solvent gas. These conditions cause the

liquid polymer to chemically react and form solid strands.

4 As the fibers exit the cell, a specific amount of the solid strands are


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bundled together to produce the desired thickness. This is done with a

compressed air device that twists the fibers together. In reality, each

fiber of spandex is made up of many smaller individual fibers that

adhere to one another due to the natural stickiness of their surface.

Final processing

5 The fibers are then treated with a finishing agent. This may be magnesium

stearate or another polymer such as poly(dimethyl-siloxane). These

finishing materials prevent the fibers from sticking together and aid in

textile manufacture. After this treatment, the fibers are transferred

through a series of rollers onto a spool. The windup speed of the entire

process can be anywhere from 300-500 mi (482.7-804.5 km) per

minute depending on the thickness of the fibers.

6 When the spools are filled with fiber, they are put into final packaging and

shipped to textile manufacturers and other customers. Here, the fibers

may be woven with other fibers such as cotton or nylon to produce the

fabric that is used in clothing manufacture. This fabric can also be dyed

to produce a desired color.


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PROPERTIES

PHYSICAL CHEMICAL

Density: The density of spandexfilaments ranges from 1.15 to 1.32 g/cc,the fibres lower density being based on

polyesters.

Acid: Good resistance to most of

acids unless exposure is over 24

hours.

Moisture regain: The moisture offibres from which the surface finish has

been removed lies between 0.8 & 1.2%

Alkalies: Good resistance to mostof the alkalies, but some types ofalkalies may damage the fibre

Length: It can be of any length. May beused as filament or staple fibre

Organic solvents: offerresistance to dry cleaning solvents

Colour: It has white or nearly whitecolour. Bleaches: can be degreaded by

sodium hypochloride. chlorine

bleach should not be used.

Luster :-It has usually dull luster. Dyeing: A full range of coloures isavailable. Some types are more

difficult to dye than others.

Strength: Low strength compared tomost other synthetic fiber..Elasticity: Elastic properties areexcellent. This is the outstandingcharacteristic of the fibre.


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Fibres and Yarns 31

END USERS

The primary use for spandex fibers is in fabric. They are useful for a number

of reasons. First, they can be stretched repeatedly, and will return almost

exactly back to original size and shape.

Second, they are lightweight, soft, and smooth. Additionally, they are easily

dyed. They are also resilient since they are resistant to abrasion and the

deleterious effects of body oils, perspiration, and detergents.

They are compatible with other materials, and can be spun with other types of

fibers to produce unique fabrics, which have characteristics of both fibers.

Spandex is used in a variety of different clothing types. Since it is lightweight

and does not restrict movement, it is most often used in athletic wear. This

includes such garments as swimsuits, bicycle pants, and exercise wear.

The form-fitting properties of spandex makes it a good for use in under-

garments. Hence, it is used in waist bands, support hose, bras, and briefs.


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Fibres and Yarns 32

YARNS

Yarn is a long continuous length of interlocked fibers, suitable for use in theproduction of textiles, sewing, crocheting, knitting, weaving, embroidery and

ropemaking. Thread is a type of yarn intended for sewing by hand or machine.Modern manufactured sewing threads may be finished with wax or other

lubricants to withstand the stresses involved in sewing. Embroidery threadsare yarns specifically designed for hand or machine embroidery.

o Spun yarn is made by twisting or otherwise bondingstaple

fibrestogether to make a cohesive thread.

Twisting fibres into yarn in the process calledspinningcan be

dated back to theUpper Paleolithic, and yarn spinning was one of

the very first processes to beindustrialized.

Spun yarns may contain a single type of fibre, or be a blend of

various types. Combiningsynthetic fibres(which can have high

strength, lustre, and fire retardant qualities) with natural fibres(which have good water absorbency and skin comforting

qualities) is very common. The most widely used blends are

cotton-polyesterandwool-acrylic fibreblends. Blends of different

naturalfibres are common too, especially with more expensive

fibres such asalpaca,angoraandcashmere.Bambooyarn is a

less expensive type that is a recent innovation.

Yarns are selected for different textiles based on the

characteristics of the yarn fibres, such as warmth (wool), lightweight (cotton or bamboo), durability (nylon is added to sock

yarn, for example), or softness (cashmere, alpaca). Acrylic and

cotton yarns are the least expensive.

Yarns are made up of a number of plies, eachplybeing a single

spun yarn. These single plies of yarn are twisted together (plied)

in the opposite direction to make a thicker yarn. Depending on the

direction of this final twist, the yarn will be known as s-twistor z-

twist. For a single ply, the direction of the final twist is the same
http://en.wikipedia.org/wiki/Staple_(textiles)http://en.wikipedia.org/wiki/Staple_(textiles)http://en.wikipedia.org/wiki/Staple_(textiles)http://en.wikipedia.org/wiki/Fibrehttp://en.wikipedia.org/wiki/Fibrehttp://en.wikipedia.org/wiki/Spinning_(textiles)http://en.wikipedia.org/wiki/Spinning_(textiles)http://en.wikipedia.org/wiki/Spinning_(textiles)http://en.wikipedia.org/wiki/Upper_Paleolithichttp://en.wikipedia.org/wiki/Upper_Paleolithichttp://en.wikipedia.org/wiki/Upper_Paleolithichttp://en.wikipedia.org/wiki/Industrializedhttp://en.wikipedia.org/wiki/Industrializedhttp://en.wikipedia.org/wiki/Industrializedhttp://en.wikipedia.org/w/index.php?title=Synthetic_fibres&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Synthetic_fibres&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Synthetic_fibres&action=edit&redlink=1http://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Woolhttp://en.wikipedia.org/wiki/Woolhttp://en.wikipedia.org/wiki/Acrylic_fibrehttp://en.wikipedia.org/wiki/Acrylic_fibrehttp://en.wikipedia.org/wiki/Acrylic_fibrehttp://en.wikipedia.org/wiki/Naturalhttp://en.wikipedia.org/wiki/Naturalhttp://en.wikipedia.org/wiki/Alpaca_woolhttp://en.wikipedia.org/wiki/Alpaca_woolhttp://en.wikipedia.org/wiki/Alpaca_woolhttp://en.wikipedia.org/wiki/Angora_woolhttp://en.wikipedia.org/wiki/Angora_woolhttp://en.wikipedia.org/wiki/Angora_woolhttp://en.wikipedia.org/wiki/Cashmere_woolhttp://en.wikipedia.org/wiki/Cashmere_woolhttp://en.wikipedia.org/wiki/Cashmere_woolhttp://en.wikipedia.org/wiki/Bamboohttp://en.wikipedia.org/wiki/Bamboohttp://en.wikipedia.org/wiki/Bamboohttp://en.wikipedia.org/wiki/Plyinghttp://en.wikipedia.org/wiki/Plyinghttp://en.wikipedia.org/wiki/Plyinghttp://en.wikipedia.org/wiki/Plyinghttp://en.wikipedia.org/wiki/Bamboohttp://en.wikipedia.org/wiki/Cashmere_woolhttp://en.wikipedia.org/wiki/Angora_woolhttp://en.wikipedia.org/wiki/Alpaca_woolhttp://en.wikipedia.org/wiki/Naturalhttp://en.wikipedia.org/wiki/Acrylic_fibrehttp://en.wikipedia.org/wiki/Woolhttp://en.wikipedia.org/wiki/Polyesterhttp://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/w/index.php?title=Synthetic_fibres&action=edit&redlink=1http://en.wikipedia.org/wiki/Industrializedhttp://en.wikipedia.org/wiki/Upper_Paleolithichttp://en.wikipedia.org/wiki/Spinning_(textiles)http://en.wikipedia.org/wiki/Fibrehttp://en.wikipedia.org/wiki/Staple_(textiles)


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Fibres and Yarns 33

as its original twist.

Filament yarn consists of filament fibres (very long continuous fibres)

either twisted together or only grouped together. Thickermonofilaments

are typically used for industrial purposes rather than fabric production or

decoration.Silkis a natural filament, and synthetic filament yarns are

used to produce silk-like effects.

Texturized yarns are made by a process of air texturizing (sometimesreferred to astaslanizing), which combines multiple filament yarns into ayarn with some of the characteristics of spun yarns.

Yarn Twist:

Yarn Twist is the measure of the spiral given to a yarn in order tohold the constituent fibres or threads together.According to textileinstitute Twist is the spiral disposition of the components of athread which is usually the result of the relative rotation of the twoends.
http://en.wikipedia.org/wiki/Monofilament_linehttp://en.wikipedia.org/wiki/Monofilament_linehttp://en.wikipedia.org/wiki/Monofilament_linehttp://en.wikipedia.org/wiki/Silkhttp://en.wikipedia.org/wiki/Silkhttp://en.wikipedia.org/wiki/Silkhttp://en.wikipedia.org/wiki/Taslanizinghttp://en.wikipedia.org/wiki/Taslanizinghttp://en.wikipedia.org/wiki/Taslanizinghttp://en.wikipedia.org/wiki/Taslanizinghttp://en.wikipedia.org/wiki/Silkhttp://en.wikipedia.org/wiki/Monofilament_line


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Fibres and Yarns 34

Types of Yarn Twist:

According to direction of twist, it is of two types: -1. S- Twist2.Z- Twist.

S- Twist: A single yarn has S twist if, when it is held in the vertical

position. The fibres inclined to the axis of the yarn conform in the

direction by slope to the central portion of the letter S.

Z-Twist: A single yarn Z Twist if, when it is held in the vertical

position, the fibres inclined to the axis of the yarn conform in thedirection of slope to the central portion of the letter Z.

YARNS

SimpleYarn

DecorativeYarn

Chenille Boucle Nub Flake Slub Spiral


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Fibres and Yarns 35

SIMPLE YARNSSimple yarns are those yarns with uniform size and regular surface. They have

varying degrees of twist, ranging frim loose to moderate, tight or hard twist. Single,

ply, and cord yarns can all be simple yarns if their components are uniform in size

and have a regular surface. When one strand of fibers is twisted together evenly, it is

classified as simple single yarn. Two simple, single yarns twisted together can create

a simple ply yarn.

DECORATIVE YARNSYarns made to create interesting decorative effects in the fabrics into which they are

woven are known as novelty or decorative yarns. The spinning process can produce

decorative effects by varying the amount of twist or by twisting together yarns of

different amounts of twist in them. Such yarns can give fabrics limitless textural

effects of various color combinations. Decorative yarns can be of the following types:

BOUCLE YARN

These yarns are ply yarns. An effect yarn forms irregular loops around the

base yarn or yarns. Another yarn binds or ties the effect yarn to the base.

The boucle effect is created by allowing one of the plies to remain slack

during the twist operation, causing it to twist n itself and form a loop.

Ratine Yarns are similar to boucle in construction. the loops in this type of yarn are

spaced evenly alongthe base yarn.

Snarl Yarn are another type of loop yarn in which two or more single yarns

under different tension are twisted together.


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FLAKE YARN

This yarn is made of loosely twisted yarns that are held in place either by a base yarn

as it twists or by a third ir binder yarn. These yarns are relatively weak and are used

in the filling to achieve decorataive surface effects. This yarn is limited to fancy uses.

NUB YARN

Nub yarns are made by twisting the effect ply around the core ply

many times within a very short space, causing bumps or nubs that

may be spaced at intervals along the yarns. Variations can be

made when two effect plies each of different color, may be used, and the nubs

arranged so that the colors are alternated along the length of the yarn.

SLUB YARN

Slub yarns may be either ply or single yarns of staple fibers. The

slub effect is created by varying twist in the yarn, allowing areas

of looser twist to be created. This produces a long, soft area in

the fabric called a SLUB. Slub yarns are irregular in diameter. Yarns made in this

way have areas of varying twist, causing weaker areas in the yarn. Filament yarns


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Fibres and Yarns 37

can be spun with varying degrees of twist. These yarns also created a stubbed

appearance. In fabrics. Such filament yarns are known as thick-and-thin yarns.

SPIRAL YARN:

Yarns are made of two plies, one soft and heavy, the other fine.

The heavy yarn winds around the fine yarn. Spiral yarn is also

known as the corkscrew yarn.

CHENILLE YARN

The term chenille is derived from the French word for caterpillar

as the yarn resembles a caterpillar. This type of yarn is made by a

completely different process. First, leno-weave fabric is woven,

this fabric is cut into strips, and these strips, which have a soft pile

on all sides, are used as yarns. These are not yarns in the traditional sense of

twisted fiber but have been taken through a series of preliminary stages before being

readied for use.

fibres n yarn

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