Aisha Project

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Dedication

Dedicated to our parents whose hands are alwaysraised in prayers for our success and we paid our

gratitude to beloved teachers, our friends and to all

others who prayed for us.

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Acknowledgements

All praise for Almighty Allah, most compassionate, source of knowledge and wisdom and

creator of all the universe of logic, call us to think, about what is happening around us, as there is

indication in them for believers.

All our respect is for Holy Prophet (PBUH) for enlightening our conscience with essence of faith

and knowledge.

We are extremely thankful to Mr. Mansoor Fiaz, lecturer, NTU, whos technical Guidance and

help enabled us to complete our project.

We are greatly thankful to Mr. Saad Ullah, lecturer, NTU, without whom technical

expertise, intellectual help and persistent cooperation we would not have been able to carry out

our work.

U.S DENIM MILLS LAHORE:

Really it was a great task and a troublesome process to make procedures and parameters being in

practice in U.S DENIM, one of the esteemed Textiles Mills in Pakistan.

But in this regard we are very thankful to all the managerial and technical staff members who

cooperated with us.

We are especially thankful to the Mr. Irfan Malik, project manager, for allowing us to make the

required fabric samples. We wish to thanks to Miss Rashida Perveen (Head of RNDDepartment), Mr. Hassan Ashraf (Assistant Manager), Miss Sadaf Mehmood (Assistant

Manager) who not only allowed us to conduct our project, but also provided us every facility

there.

CRECENT BAHUMAN LTD PINDIBHATTIAN:

We are equally thankful for the corporation and guidance of all the managerial and technical

staff members at CRECENT BAHUMAN LTD.

We are grateful to Mr.Rehman, SDM (GWP), Mr. Sajid Tanoli, SAM (Weaving) for their keen

interest and support towards our project.

We would also like to thanks to Mr.Imran Tasleem, SAM (Testing and Quality Control) who

help us to carry out the necessary testing work.

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SHRINKAGE .................................................................................................................31Types of shrinkage: .................................................................................................................31

Construction Shrinkage: ......................................................................................................... 32

Processing Shrinkage: .............................................................................................................32

Factors affecting shrinkage: ....................................................................................................33Compressive shrinkage: ..........................................................................................................35

Parameters for process control: .............................................................................................. 36SHRINKAGE EVALUATION ......................................................................................37

CONSTRUCTION SHRINKAGE ......................................................................................... 37

Shrinkage in Rigid and Stretch Denim ..............................................................................39

Shrinkage in Strecth Denim due to varying Picks per Inch .............................................. 41

S Shrinkage due to varying Draft and Denier ....................................................................43

Shrinkage due to varying Weft Count ............................................................................... 45

Shrinkage Due to varying Yarn Types ..............................................................................47

Shrinkage (%) due to varying Weave Type .......................................................................49Shrinkage (%) due to Slub Yarns ...................................................................................... 51

PROCESSING SHRINKAGE ................................................................................................ 52

Shrinkage (%)due to varying Washing Time ....................................................................56

Shrinkage (%) due to varying Temperature .......................................................................58

Shrinkage (%) due to different Washing Cycles ...............................................................60

Shrinkage (%)due to Washing Type ..................................................................................62

Shrinkage % due to different Industrial Washing Types ................................................... 64

STRETCH EVALUATION ...........................................................................................67Measuring the Stretch and Growth: ........................................................................................ 67

Stretch % due to different Weave Type: ............................................................................68

Variation in Stretching % due to Heat Setting ...................................................................70

SKEWNESS ....................................................................................................................71

CONCLUSION & RECOMENDATIONS ...................................................................74

LIST OF TABLES

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TABLE No. PAGE No.

1 14

2 14

3 25

4 40

5 42

6 44

7 46

8 48

9 50

10 52

11 56

12 57

13 59

14 61

15 63

16 65

17 67

18 69

19 70

20 71

21 73

LIST OF FIGURES

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FIGURE No. PAGE No.

1 16

2 17

3 18

4 19

5 22

6 23

7 35

8 40

9 41

10 42

11 43

12 44

13 45

14 46

15 47

16 48

17 49

18 50

19 51

20 52

21 53

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22 58

23 58

24 60

25 60

26 61

27 62

28 64

29 64

30 66

31 67

32 69

33 70

34 71

35 74

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INTRODUCTION

The termshrinkage can simply be defined as a change in the dimensions of a fabric or

garment. This dimensional change may be in a positive (growth) or negative (shrinkage)

direction for fabric length, width, and thickness. In garment form, the shrinkage characteristics

relate not only to a change in fabric dimensions, but also can relate to other parameters such as

seam puckering and overall garment fit.

The fabric shrinkage can cause problems in two areas during garment manufacture or

during subsequent laundering by the ultimate customer. At various stages during garment

manufacture the fabric is pressed in a steam press such as a Hoffman press, where it is subjected

to steam for a short period, while being held between upper and lower platens of the press.

Similarly laundering is a more vigorous process than pressing and it usually involves mechanical

agitation, hot water and detergent. Tumble drying can also affect the shrinkage as the material is

wet at the beginning of the drying process, the material being agitated while heated until it is

dried. Acceptance, rejection, and discount penalties are dependant on shrinkage percentage.

Further, in depth analysis of shrinkage result of a particular fabric can allow for a better

understanding of the causes of inconsistent or high shrinkage. The main focus of our research

work was shrinkage in stretch denim. In denim industry control of shrinkage is the major

challenge particularly in stretch denim.

Certain types of clothing, like sports wear, stretchable denim, is made to be close fit to

the body. Fabric of which such clothing is made, should be able to stretch in order to

accommodate firstly the donning and removal of the garment and secondly any activity

undertaken while wearing it. So the garment remains close fitting and does not appear baggy.

This stretch has to be followed by the complete recovery of the original dimensions.

Denim:

Denim is a durable twill-woven fabric with colored (usually blue) warp and white filling

threads; it is also woven in colored stripes. Denim is yarn-dyed and mill-finished and is usually

all-cotton, although considerable quantities are of a cotton-synthetic fiber mixture like cotton and

spandex in case of stretchable denim. Over last few decades denim fabric has become very

popular all over the world for its attractive indigo blue shades. Denim is affordable, comfortable,

fashionable, and durable and offers a variety of shades and colors. Normally denim is used for

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jeans jackets and shirts but its versatility also finds applications in furniture, upholstery, bed

covers, curtains etc.

Mostly warp yarn sheet is dyed with indigo dyed in rope form and the filling yarns are

left undyed. The properties of indigo dye account for the wide variety of color designs that are

available on denim materials. Indigo dye in its normal form is a vibrant blue, it is insoluble in

water and it will not dye cotton fiber. In order to dye cotton, the indigo must be converted to a

water-soluble leuco form and then applied to the cotton. Generally, the weaves undertaken 2/1

and 3/1 twill. However denim can also made in 4/1 twill even plain weave denim are also in

considerations as in modern world denim is not a fabric but a trend. Warp faced twill is usually

employed due to which the denim fabric is bluer on the face side and almost white on the black.

The denim fabric is found in different weights. The weight of the denim fabric usually

determines what the final garment application will be:

3.5 8.0 ounces per square yard blouses,tops,shirts and top of bed fabrics

8.0 16.5 ounces per square yard trousers,jeans,jackets and upholstery

The origin of the term denim can be traced to late 16th century France where a fabric

known as serge de Nmes (Twill from Nmes) was very popular. Originally, it was strong

material made from wool. By the 1700s, it was made from wool and cotton. Only later was it

made solely from cotton. By the late 19th century, weavers in America made the twills in same

fashion as the European denim.

Twill weaves:

Twill weaves are formed by interweaving the warp and weft threads with each other in

such a manner that diagonal lines are formed in the fabric. These lines can be made to run from

left to right or right to left. Diagonal lines are frequently visible on the face of the fabric as well

as on the back of the fabric. Twill weave fabrics have either a right hand or a left hand diagonal.

If the diagonal moves from the upper right to the lower left of the fabric, when viewing in a

longitudinal direction, it is referred to as right hand twill or Z-twill. If the diagonals move from

the upper left to lower right, it is called left hand twill or S-twill.

Twill weave fabrics have a distinctive and attractive appearance. They are frequently

more expensive than plain weaves. Twill weaves may also be called as serge or diagonal weaves.

The most common types of twill weave are

Herring bone twill

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Pointed twill

Diamond twill

Fabrics made from twill weave:

Twill weaves are most widely used after plain weaves. They are used for both civilian

and military uses. Among them are the parachute fabrics of all kinds, denim.gabardine, jean,

blanket and others.

Methodology of Project

Place of Project: US Denim Mills (PVT) Ltd

Crescent Bahumn (PVT) Ltd

Department involved: Weaving Department

Research and Development Department

Finishing Department

Garment Wet Processing Department

Physical Testing Lab

Looms Used for Fabric Manufacturing: Automatic Picanol Omni Plus US Denim Ltd

Toyota JAT 710 In CBL

Construction Shrinkage (First Portion of Project)

Constant Factors:

Washing Conditions

Temperature

Time

Washing types

Washing cycles

Variable Factors:

Picks per inch

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T3 10 spandex 70+3.91 40 3/1 Z-twill

T4 10 spandex 40+3.25 40 3/1 Z-twill

T510 lycra

slub70+3.91 40 3/1 Z-twill

T610 lycra

slub40+3.25 40 3/1 Z-twill

T7 10 lycra 70+3.91 44 3/1 Z-twill

T8 10 lycra 40+3.25 44 3/1 Z-twill

T9 10 spandex 70+3.91 44 3/1 Z-twill

T10 10 spandex40+3.25

44 3/1 Z-twill

T1110 lycra

slub70+3.91 44 3/1 Z-twill

T12

10 lycra

slub 40+3.25 44 3/1 Z-twill

T13 10 lycra 70+3.91 40 2/1 Z-twill

T14 10 lycra 40+3.25 40 2/1 Z-twill

T15 10 spandex 70+3.91 40 2/1 Z-twill

T16 10 spandex 40+3.25 40 2/1 Z-twill

T1710 lycra

slub70+3.91 40 2/1 Z-twill

T1810 lycra

slub40+3.25 40 2/1 Z-twill

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T19 14 lycra 70+3.91 40 3/1 Z-twill

T20 14 spandex 70+3.91 40 3/1 Z-twill

T2114 lycra

slub70+3.91 40 3/1 Z-twill

T22 10 lycra 70+3.91 40 3/1 Z-twill

T23 10 spandex 70+3.91 40 3/1 Z-twill

T2410 lycra

slub

70+3.91 40 3/1 Z-twill

T2510

polylycra70+3.91 40 3/1 Z-twill

Table 1

Every trial was manufactured two meter long. 3HL washes were used for shrinkage

measurement.

DETAILS OF FABRIC MANUFACTURED FOR WASHING SHRINKAGE :

FabricNo.

WarpCount

WeftCount

Ends/inch Picks/inchWeaveType

FinishType

F1 9.2 14/1+30D 64 48 2/1 RHT Mercerized

F2 6.3 16/1+40D 68 44 2/1 RHT Mercerized

F3 9 9/1+70D 64 45 2/1 RHT Mercerized

F4

9.2 14/1+30D 64 48 2/1 RHT Regular

F5 6.3 16/1+40D 68 44 2/1 RHT Regular

F6 9 9/1+70D 64 45 2/1 RHT Regular

Table 2

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Ball warping

Figure 2

Rope Dyeing:

Denim is yarn-dyed fabric with the warp yarns dyed with indigo dye and the filling

yarns left undyed process. In rope dyeing, ball warps are continuously fed into the rope or

chain-dyeing range for application of the indigo dyeing. Typically, 12-36 individual ropes of

yarn are fed side-by-side simultaneously into the range. The ropes are kept separate from each

other throughout the various parts of the dye range. The dye is layered by using multiple

passes of rope into the soluble dye and then exposing to the air for oxidation. The ropes are

then dried .After drying, the ropes are coiled into the larger tubs.

After dyeing the color of the yarn is checked either visually or instrumentally. It is

possible for the denim fabric to be finished and sold without going through any drying process.

These fabrics are known as natural denims sometimes called as bull denims. It is also possible

to manufacture the fabric with both warp and weft dyed.

2.3. Slasher dyeing

For certain manufacturers, the rope or chain dyeing of indigo is not possible or

desirable, so slasher dyeing has become a reasonable alternative method. A slasher is a range is

normally employed to apply size formulations onto warp yarns before weaving. Here the yarns

sheet from the warping beam is fed into the scouring section followed by a dyeing section

where the indigo is applied. Slasher dyeing ranges have a number of advantages and unique

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characteristics.

Figure 3

Re-beaming:

Beaming or re-beaming involves pulling the ropes of yarn out of storage tubs and moving

them upward to a guiding device. This upward travel allows the ropes to untangle before

nearing the beamer head. Once the ropes come down from the guiding device, they go

through tensioning rollers to help further the separation of the ropes before going through acomb at the rebeaming head, which separates individual yarn ends and keeps them parallel to

one another.

Sizing:

The main purpose for sizing warp yarns is to increase the strength of the warp sheet,

abrasion resistance; the protective coating also reduces the hairiness of the yarn. The beams

from the beaming process are creeled on the back of the machine. The yarns sheets re guided

into the size box. After leaving the size box the yarn sheets are squeezed and dried and arewound onto a beam which is directly put onto the loom for weaving purpose. In sizing the

number of ends required for the specific fabric width is achieved. The size is applied to the

yarn consist of starch, PVA etc.

Weaving:

Fabric is woven by interlacing of two sets of yarns perpendicular to one another. Warp

yarns are fed from the loom beam and are then directed through drop wires, heddles, and a

comb-like device called a reed while the weft yarn is fed from larger packages located outside

of the machine. The sequence of interlacing two sets of yarn can be varied to produce many

weave design. The denim is mostly woven as 3/1 twill 2/1 twill.

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Figure 4

Denim finishing

Finishing of denim fabric is carried out after weaving .the finishing procedure involves

the following steps:

Singeing

Skewing

Pre drying

Shrinking

Drying

The grey fabric is brushed to remove the loose lint and fluff from the fabric surface.

The fabric is then singed in order to burn off the protruding fibers from the fabric surface.

Normally the denim fabric is singed twice. The potential shrinkage of grey denim fabric variesfrom 8-18%.Hence the denim fabric must be pre shrunk so that the finished fabric does not

show higher shrinkage during subsequent washing. Denim fabric is skewed during finishing

process as fabric is skewed during washings. Sometimes the fabric is treated with softeners and

lubricants to give the fabric soft and pleasing handle. After finishing cutting and sewing of

garment is done and then wet processes are applied to the garment.

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3. SPANDEX

Spandex is incorporated into cotton fabrics to impart a greater level of stretch and

recovery than can be achieved by cotton alone. Prevalent in womens wear, but

expanding into other product categories, cotton/spandex blends can be found in knit

goods such as skirts, leggings, and tops, or in most all types of woven goods such as

stretch jeans. Some features of spandex are listed below:

High elasticity and recovery

Low moisture absorption

Resistant to normal apparel exposure to sunlight

Resistant to most common chemicals

Spandex is not degraded under normal acidic or alkaline conditions, and it is notusually affected by small amounts of knitting oils and lubricants. However, it is known to

lose strength when subjected to prolonged UV radiation exposure or chlorine.

Stretch values may vary depending upon the fabric construction, the amount of

spandex used, the denier of the spandex, and the heat-setting conditions. Typical stretch

levels for cotton knit fabrics with spandex are in the 50-100 percent range thus spandex

may in every course or in alternating courses.

In woven goods, spandex may be found in the filling yarns, in the warp yarns, or

in both. Construction of the woven fabric is paramount in determining the achievable

amount of stretch. Typically, the spandex used in woven goods will be found in a core

spun yarn; however, the form in which the spandex is used depends upon the fabric

construction, performance requirements, and experience of the designer. The choice of

denier depends on the aesthetic properties that are desired. Stretch levels are typically 15-

50 percent for woven structures.

3.1. Stretch Denim:The popularity of stretch denims with SPANDEX (elastane) has increased

significantly in recent years. Consumers prefer the stretch denim fabrics combining

classic cotton aesthetics with improved fit and comfort. The denims containing spandex

possess a higher extensibility and recoverability, which can increase comfort and freedom

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of action in various types of jeans. Just a small percentage of spandex (elastomeric yarn)

will enhance appearance by approving shape retention, reducing wrinkles and bringing

new fluidity and drape ability to garments. To create stretch denim, which meets the high

requirements of consumers and cutters, the right combined elastic yarn, fabric formation,

dye and finishing have to be chosen.Stretch Jeans can be made body hugging or even

loose, it provides ultimate comfort and gives great shape to your body. By default Stretch

Denim will be made body hugging unless you specify in the comment box of the

measurement form that you dont want body hugging. The waist/seat of Stretch jeans may

measure less than you order because they will stretch to much more than the waist/seat

measurement you will have specified.

Spandex Type Selection:For cotton rich denim (cotton contain>96%), regular spandex or Heat-Set spandex

is used. Regular spandex can provide best stretch power. Heat-Set is a new elastane type

which provides better width and can be heat-set at temperatures that are 20 oC lower than

conventional elastane, or at tenter-frame speeds that are 20% to 50% faster. For no heat-

set denim, heat-set type can reduce denim stone wash shrinkage and definitely offers

wider width of fabrics. Also, heat-set type could reduce the shrinkage variation and width

variation between lots and pieces of denim products.

The right Spandex deci-tex choice is based on final fabric weight. 70 D spandex is

usually chosen for most denims. However, for some lighter weight and heavy weight

denims, 40 D and 140D spandex can also be used.

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Figure 5

Stretch Denim Fabric:

Primary considerations in weaving of stretch denim are fabric design and

construction.

The available stretch of the fabric is mainly dependent on the difference between

the maximum reed width and the fully relaxed fabric construction.

Too tight a fabric structure and too high a yarn count and yarn twist factor will

prevent weft contraction, so that the fabric remains wider than the required width

and lacking in stretch ability.

Stretch denims are usually of the 3/1-twill structure with the warp yarn floating on

the fabric surface. A wide 2 to 2.5 cm tape with alternate yarn floats on the face and back is

preferred in order to prevent selvedge from rolling or curing in loose denim

structures.

The weft yarns should be fully stretched during weaving to prevent the formation

of kinks.

Weft supply package must be uniformly wound.

Finishing:

Stretch denims with spandex are finished to obtain the desired stretch, recovery

and dimensional stability and to meet the fabric width requirement. Generally speaking,

the finish processing of stretch denim containing spandex follows closely the operational

sequence used for conventional non-stretch denim with the exception of relaxation and

heat-setting steps. In order to obtain good denim fabrics with nice stretch, high recovery

and low shrinkage, it is important to carefully control processing condition of relaxation

and heat-set procedures.

Heat Setting:

Heat setting is done to re-stretch and stabilize the fabric close to the desired

width. The fabric should be heat-set on a pin-tenter with much care given to width control

and heat distribution. The framing width will depend on the fabric weight, width, and

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stretch level. During the heat-setting stage, the spandex is held under tension, and this

result in a denier reduction that corresponds to a reduction in power and reduction in

width retraction. More severe heat-set conditions (higher temperature or slower speed)

can produce denims with lower stretch, lower shrinkage

Figure 6

Heat-setting temperatures for woven range from 360-385F (182-196C) and are

chosen according to the desired performance properties of the fabric. Because a small

amount of shrinkage remains in the spandex after setting and because heat-setting does

not prevent the cotton fiber from shrinking, the set width for filling stretch fabrics

should be 5-15 percent higher than the desired width to account for any additional

shrinkage that may occur in wet processing. To prevent curling or edge folding, the

selvage should be constructed to accommodate the width shrinkage.

No-Heat setting Denim

Some times, stretch denim does not pass through heat set process and directly go

to garment manufacturers. In this case, fabric has very high shrinkage (normally higher

than 13%), high shrinkage variation and width variation. Special care must be taken in

garment sizing and pattern design, cutting and stone wash processing for such fabrics.

Ensure the fabrics, which makes up of a piece of garment, possess the same level of

shrinkage, or come from a same piece of denim. In this way, the garment defects related

to shrinkage variation could be reduced remarkably.

Sanforizing

In Sanforizing, fabrics are first subjected to a fine water spray, steam and fed

onto a compression blanket at 80 PSI (551.6 kPa) nip pressure. A Palmer unit operating

at 120 PSI

(827.7

kPa)

steam

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Desizing:

Complete desizing and preparation is the first step in denim wet processing. If

denim is not properly desized, then the stone washing process will not be completed

successfully, enzymes will be wasted, streaks and lines may be set in garments.

During sizing the warp threads are sized in order to sustain considerable strain

and abrasion during weaving. The size is normally based on starch, PVA, binders, waxes

and lubricants. Complete removal of size is absolutely essential subsequent washing of

denim.

The degradation of insoluble starch can carried out by hydrolysis or by oxidation.

Hydrolysis is generally carried out by using dilute mineral acid or enzyme. An acid may

cause degradation of cotton. Enzymes are very specific and effective in their action and

act only on starch without effecting cellulose.

Bio technology:

The majority of industrial applications of biotechnology are based upon

fermentation process using microorganisms and enzymes to digest, transform and

synthesize natural material from one form into other.

The word Bio Wash is understood as a washing down treatment of textile

materials, which involves an enzymatic treatment.

In the field of denim washing enzymes play a significant role at the pre-treatment

stage i.e. desizing and finishing stage. Enzymatic desizing is most effective and popular

method used. In the enzyme process, desizing is carried out by using enzyme amylase,

which hydrolysis the starch of sized warp. When amylase starts action with starch, the

starch is converted into sugar which further oxidizes into maltose and then finally goes

into glucose which is soluble in water.

The denim fabric has sized warp yarns coated with a film of starch. Amylase the

starch splitting enzyme acts only on the basic constituents of starch while the inner cotton

fibers remain intact. This the basic advantage of enzymatic desizing.

Benefits of cellulosic treatment:

The general benefits of cellulosic treatment includes

Prevention of fuzz and pill

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Increased smoothness

Softness

Increased luster and superior color brightness

Improved handle Fashionable wash-down effects

Stone Washing:

During the washing of denim garments the surface dyes removal by abrasion is

enhanced by stones. Stone washing is the classical washing procedure which is supposed

to give denim the character of having already been worn for a long period of time and

having been washed several times.

Stone washing exposes strong abrasion marks, especially on seams and edges.

The handle is comfortably soft and full, but no harsh stiff or board.

Pumice stone has been used since the introduction of stone washed jeans in the

early 1980s. A pumice stone ideal for an excellent stonewash process should be white,

cleaned, washed, rounded and free from foreign stones and impurities.

Freshly dyed jeans are loaded into large washing machines and tumbled with

stones. As the wash cylinder rotates, the cloth fibers are repeatedly pounded and beaten

as the tumbling stones ride up the paddles inside the drum and fall back down onto the

fabric.

The pumice abrades the surface of the jeans like sandpaper, removing some dye

particles from the surfaces of the yarn.

Many problems are associated with stone washing of indigo denim garments i.e.

the quality of the abrasion process is difficult to control. Heavy abrasion can damage the

quality of the products and the life of the equipment, and increases production costs. A

further disadvantage is water pollution problem during the disposal of liquor, containing

stone dust. To overcome the drawbacks of stonewashing, the Biostoning technique is

used nowadays. It provides the same effect as traditional stone washing.

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Biostoning:

"Biostoning" was introduced in Europe in 1989 and then quickly adopted in the

US the following year. Biostoning relies on the action of enzymes to modify the fabric

surface. Enzymes have been used in the textiles industry since the turn of the century to

remove starchy and waxy residues from raw materials and to give fabric a uniform finish.

The enzymes used in Biostoning are known as "cellulases" which attack primarily on the

surface of fiber leaving its interior intact yielding the desired look and softer finish.The

enzyme hydrolysis the cellulose into substances which can be easily removed resulting in

attractive blue shades.

Back staining;

In the early days, one problem with Biostoning was "back staining." Back staining

happens when loosened dye particles redeposit onto the back surface of the fabric,

causing discoloration. The indigo is washed out of blue yarn in denim and it may stain

the white yarn. However the prevention is done by controlling the pH of dye bath.

Advantages of Biostoning:

The enzymatic washing has the following advantages over the stone washing:

Biostoning is by far the most economical and environmentally friendly

way to treat denim. It provides the lighter and cleaner working conditions and

environmentally friendlier processes. Enzymatic washing prevents damage of machines and the garments,

improve quality, eliminating the removal of dust from washed garments.

Superior garment quality with respect to softness, luster, fluff removal and

minimum damage to the machine and garment.

Process is user friendly, can be accomplished under mild physical and

chemical conditions, and consumes less energy, non-corrosive to equipment and

non-polluting to environment.

Reproducible effect are obtained under controlled conditions in terms of

degree of fading, surface smoothness and soft hand.

Allows 30-50% more garment load

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Labor intensive clean up of stone from fabric, machine, and drain lines is

avoided.

Acid washing:

Acid washed denim is chemically processed denim that stripped the top layer of

color off to a white surface with the undertones of navy blue remaining in the jeans.

At first the Acid Wash process involved soaking pumice in Industrial Strength

Chlorine however it was discovered that potassium permanganate was more controllable

and just as strong an oxidizer. Pumice stones are simply marinated in it and then it is

vacuum packed to the required moisture level. The garments are then treated with these

stones to get the required faded look. But it is not used for stretch denim as it may

damage the Lycra core.

Bleaching Wash:

Denim garments are bleached in order to achieve light shades. It actually

produces the whiteness and brightness in fabric. For this purpose, strong oxidative agents

such as sodium hypochlorite or potassium permanganate are used during washing.

Indigo is easily destroyed by sodium hypochlorite at temperature of 40-50c.After

bleaching residual hypochlorite has to be removed because apart from the formation of

unpleasant odour, fiber damage and yellowing will arise. So an anti-chlorination agent is

used for this purpose. Depending upon the desired bleaching, different quantities of

bleaching agent are used.

Potassium permanganate is more effective at temperatures of 20-30c.The

bleaching effect can be enhanced by using acid.

Conventional hypochlorite bleaching of denim is cheap, fast and efficient but

harsh to environment and denim. Latest trend is to use the enzymes for controlled

bleaching.

Neutralization:

After the bleaching process it is necessary to clean up the garment which is done

by neutralization. The process is followed by rinsing and softeners are applied to increase

the softness and to confer a smoother appearance. The neutralization is done either by

using sodium bisulphate or hydrogen peroxide

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Tint Wash:

Tinting is a partial dyeing process. It gives the temporary color to the fabric which

can be easily washed and removed. It is just used to give the required color to the fabric.

Dyes of different color are used for the process. Direct dyes are used commonly for this

purpose. The color of the dye used is according to the customer requirement.

Important considerations:

In order to achieve quality processing, particular attention should be paid to the

following parameters

Liquor to good ratio

PH control

Temperature control

Closely controlled process time

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SHRINKAGE

The term shrinkage can simply be defined as a change in the dimensions of a

fabric or garment. This dimensional change may be in a positive (growth) or negative

(shrinkage) direction for fabric length, width, and thickness. For a cotton fabric,

shrinkage relates to the loss of the length and/or width dimensions.

Shrinkage is a dimensional change in a fabric or garment caused by an

application of a force, energy, or a change in environment that either allows the goods to

relax or forces the fabric to move in a given direction. When yarns are woven into fabrics

they are subjected to considerable tensions, particularly in warp direction. In subsequent

finishing processes such as calendaring, this stretch may be increased and temporarily set

into the fabric. The fabric is then in a state of dimensional instability, subsiquently when

the fabric is thoroughly wetted it tends to revert its more stable dimensions which results

in the contraction of yarns. This effect is usually greater in warp direction than in weft

direction.

Types of shrinkage:

There are a no of different causes of dimensional change. Some of which are

connected to one another. Relaxation shrinkage can affect any fiber type. Following types

of dimensional change are generally recognized.

Hygral expansion

Relaxation shrinkage

Swelling shrinkage

Felting shrinkage

Hygral expansion: It is a property of fabrics made from fibers that absorb moisture, in

particular fabrics made from wool. It is a reversible change in dimensions which takes

place when the moisture regain of a fabric is altered.

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Relaxation shrinkage: It is the irreversible dimensional change accompanying the

release of fiber stresses imparted during manufacture which have been set by combined

effect of time, finishing treatments and physical restraints within the structure.

Swelling shrinkage: It results from swelling and de-swelling of the constituent fibers of

a fabric due to the absorption and desorption of water.

Felting shrinkage: It results from the frictional properties of component fibers which

cause them to migrate within the structure. This behavior is normally considered to be

significant only for fibers having scale on their surface such as wool.

Shrinkage and the cause of shrinkage can be further defined or broken down into

two different types:

Construction shrinkage

Processingshrinkage.

This means that shrinkage is affected by the construction parameters of the fabric, and

it is also affected by the forces applied in processing in the dyeing and finishing

departments as well as the apparel manufacturing facility.

Construction Shrinkage:

After cotton fabric is constructed on a knitting machine or weaving loom, it has

inherent characteristics based solely on the yarn construction variables used. These

characteristics or conditions affect various specifications including shrinkage. The type of

shrinkage measured at this point is defined as construction shrinkage. Construction

shrinkage is defined as the amount of dimensional change in a fabric based solely on the

construction variables used to create the fabric.

Processing Shrinkage:

All processing steps in a finishing and garment wet processing plant affect the

dimensions of a product. Some techniques have more impact than others. These steps

create processing shrinkage, which can be defined as the dimensional change that a

process adds to or removes from the construction shrinkage of a fabric . Length and width

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dimensions are both affected, and the fabrics may either be stretched or consolidated.

Most often, the length is stretched and the width is reduced during finishing process.

Some of this shrinkage is composed of elastic shrinkage and can be easily recovered

while some of the change in dimensions may not be recovered, because the elastic limits

of the fabric as constructed have been exceeded.

In todays modern finishing plants, methods are used to attempt to overcome

processing shrinkage and reduce construction shrinkage. The dimensions of fabrics can

become set while they are deformed if they are subjected to a suitable process. Fibers that

absorb water can be set if they are deformed while in the wet state and then dried at those

dimensions. Thermoplastic fibers can be set if they are deformed at a comparatively high

temperature and then allowed to cool in the deformed state. The set may be temporary or

permanent depending on the severity of the setting conditions. During relaxation

shrinkage it is temporary set that is released. It is generally the case that deformation that

has been set can be released by a more severe treatment that than the setting treatment.

Factors affecting shrinkage:

There are many factors that relate to shrinkage. These include the

Fiber type

Yarn size and type

Construction variables

Wet processes

Finishing procedures

Apparel manufacturing techniques

Garment care methods

Cellulosic fibers are not as easily stabilized as are thermoplastic synthetics,

because they cannot be heat set to attain stability. The comfort and overall appeal of

cotton has resulted in greater demand by the consumer and by usage in the textile

industry. Therefore, the relaxation of fabrics made with cotton fibers requires either

mechanical and/or chemical means for stabilization.

The manner by which fibers are oriented in a yarn will affect certain properties of

the fabric including shrinkage. Cotton singles yarns of high twist will usually yield higher

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shrinkage values than yarns of lower twist levels and will certainly yield greater skewing

or torqueing.

Different constructions can have significantly different shrinkage characteristics.

Finishing procedures may reduce or increase the dimensional stability of the fabric. If

relaxation dryers, compactors, and/or cross linking agents are used, then the residual

shrinkage after wet processing can be reduced

Figure 7

Apparel manufacturing processes often increase the level of shrinkage in a fabric.

The laying down of the layers for cutting and the physical manipulation of the panels in

sewing are examples of where shrinkage values can be increased. In fact, garments

comprised of different fabric constructions may have some panels relax with handling in

cut-and-sew while other panels may grow.

Garment care labeling and laundering practices will have a direct influence on

shrinkage performance. If the label calls for line or flat drying, then mostly elastic

shrinkage will affect performance.

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In denim industry the shrinkage is the major problem. The excessive shrinkage

level is undesirable for the fabrics to be made into the garments and is usually controlled

in finishing processes.

Compressive shrinkage:

This is a mechanical finishing process that is used in denim industry. Compressive

shrinkage is defined as any operation performed to improve the fabric appearance or

function by physical manuplation, Steam or heat may be accompanied the physical

manipulation; however chemicals and other lubricants are seldom used. The method

includes drying, compaction, and/or chemical processes.

Fabric properties affected by the process are

Luster

Smoothness

Softness

Residual shrinkage

Hand

In a few mills compressive shrinking of denim fabric is carried out in a separate

range. A heavy duty shrinkage machine is used for shrinking of denim fabric up to 14

17%.While others use the integrated finishing range.

Integrated finishing and shrinkage:

In integrated finishing range finishing of denim fabric is carried out in a single range. In

this process the fabric is first passed through the brushing and singeing unit to remove the

loose fluff and lint from fabric surface and then padded to apply finish to the fabric.

Many different softeners and finishes are available which are suitable to denim fabric.

The fabric is then stretched by passing through two pulling devices and then skewed.

After skewing it is passed through the drying cylinders for partial drying of fabric.

Subsequently the fabric runs through a compressive shrinkage unit followed by drying

and calendaring.

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Sanforizing:

Mechanical compacting is one method of reducing residual shrinkage. The

process forces the yarns closer together and fabric becomes thicker and heavier. As a

result of this the net residual shrinkage reduces. The term Sanforized is a registered

trademark and is used to market the fabric that meets certain shrinkage specifications.

Fabric is passed through the sanforizer head followed by the steam heated cylinders used

to set the Sanforized or shrinked fabric. The key to any compacter is head where the force

is applied to move the parallel yarns closer together. More length of fabric must be fed

into the Head than the delivered one.

A sanforizer actually uses a thick rubber blanket running against a steam heated

cylinder. This thick blanket goes over a small diameter roller which stretches the convex

surface of blanket. Fabric is passed outer the stretched blanket and the fabric and blanket

come together in contact with the steam heated cylinder. At that point the rubber surface

contracts to its original length and is forced to contract an additional amount as it forms

the concave configuration of heated drum ultimately the yarns in fabric become closed.

Parameters for process control:

The main parameters that affect the shrinkage level are

Moisture

Pressure between the roller and rubber belt

Due to the continuous stretching and relaxing of blanket, heat is generated. The

blanket is then cooled by spraying water on it after the fabric has been delivered through

the unit. The degree of shrinkage is controlled by the thickness of blanket. For better

results the degree of compactness is pre-determined which is done by characterizing the

shrinkage behavior of fabric by laundering. Degree of compacting should not exceed the

degree of shrinkage.

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SHRINKAGE EVALUATION

CONSTRUCTION SHRINKAGE

Samples were made of the fabric manufactured mentioned earlier.

Then the samples were marked with the help of AATCC standard scale with thehelp of textile marker.

The samples were over-locked to avoid fraying during washing.

After marking samples were conditioned

Next the samples were washed by three home launderings (3HL).

After drying, samples were again conditioned.

In the end, shrinkage was measured for both warp and weft dimensions.

Samples:

25inch 25inch

Marked at 18inch 18inch.

Conditioning of Samples:

Temperature 21oC 1oC

Relative humidity 65% 2%

Time 4 hours before wash and 4 hours after washMachines used for 3HL

Kenmore

Vascator

Three home Laundering

Recipe:

Chemicals Quantity

Sodium per

borate

1g/l

ECE 3.85 g/l

Liquid Detergent 45 ml

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Conditions:

Temperature40o for stretchable denim

60o for rigid denim

Time67 min for every washing

cycle

Procedure:

Water and chemicals were loaded in the machine.

Samples were also added.

Then the machine was put into running position and samples were washed under

the above mentioned conditions.

After one complete washing cycle fabric samples were unloaded and dried.

Then the samples were again put into the machine and the whole procedure was

repeated.

After the completion of second cycle, the samples were again dried and the cycle

was repeated for the third time.

Shrinkage Test:

After washing and conditioning the fabric samples were measured on marks with

the help of same scale.

Shrinkage percentage was calculated in both warp and weft directions by using

the formula:

Shrinkage % = Change in length 100

Original Length

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Shrinkage in Rigid and Stretch Denim

Denim fabric without any stretch properties are known as rigid denim.

Stretch denim fabrics have pronounced values of stretch. These are made up of

the yarns having elastomeric core.

Fabric

no.Count

Fabric

Type

Denier+

draftPicks/inch

Weave

Type

Shrinkage (%)

Warp Weft

1 10 NeRigid - 40 3/1 Z twill -6.5 -13

Lycra 70+3.91 40 3/1 Z-twill -7.23 -24.84

2 14 NeRigid - 40 3/1 Z twill -2 -12.3

Lycra 70 + 3.91 40 3/1 Z-twill -3.7 -21.9

Table 4

Shrinkage (%) behaivior of Rigid n

Stretch Denim in warp

-8

-7

-6

-5

-4

-3

-2

-1

0

Rigid

Lycra

Shrinkage(%

10 Ne

14 Ne

Figure 8

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Shrinkage (%) behaivior between Rigid

n Stretch denim in Weft

-30

-25

-20

-15

-10

-5

0

Rigid

Lycra

Shrinkage

(%

10 Ne

14 Ne

Figure 9

Conclusion:

By comparing the fabrics, it was concluded that stretch denim shrinks more than

rigid denim, as core-spun yarn undergo more tensions during yarn manufacturing and

weaving of fabric. So stretch denim tends to shrink more when it acquires relax state.

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Shrinkage in Strecth Denim due to varying Picks per Inch

No. of

ObservationsCount Denier+Draft Picks/inch

Weave

Type

Shrinkage

Warp Weft

1

10 lycra 70+3.91 40

3/1 Z-

twill -6.5 -23

10

spandex 70+3.91 40

3/1 Z-

twill -5 -22.13

10 lycraslub 70+3.91 40

3/1 Z-twill -4.12 -24.5

2

10 lycra 70+3.91 44

3/1 Z-

twill -5.37 -19.510

spandex 70+3.91 44

3/1 Z-

twill -4.5 -20.25

10 lycra

slub 70+3.91 44

3/1 Z-

twill -4.5 -22.5

Table 5

Shrinkage in Warp due to Picks per inch

-7

-6

-5

-4

-3

-2

-1

0

10lycra

10

spandex

10lycra

slub

Shrinkage(%

40 Picksper inch

44 Picksper inch

Figure 10

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S Shrinkage due to varying Draft and Denier

Fabric

no. Count

Denier+

draft Picks

Weave

Type

Shrinkage (%)

Warp Weft

1

10 Lycra 70+3.91 40 3/1 Z twill -6.5 -23

10 Spandax 70+3.91 40 3/1 Z twill -5 -22.13

10 Lycra slub 70+3.91 40 3/1 Z twill -4.12 -24.5

2

10 Lycra 40+3.24 40 3/1 Z twill -6.23 -20.5

10 Spandax 40+3.25 40 3/1 Z twill -4.87 -18.75

10 Lycra slub 40+3.25 40 3/1 Z twill -4.2 -18.77

Table 6

Shrinkage (%) in Warp due to Draft+Denier

-7

-6

-5

-4

-3

-2

-1

0

10Lycra

10

Spandax

10Lycra

slub

Shrinkage(%)

70+3.91

40+3.24

Figure 12

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S h r in k a g e ( % ) in W e f t

D r a f t + D e n i e r

-3 0

-2 5

-2 0

-1 5

-1 0

-5

0

10Lycra

10

Spandax

10Lycra

slub

Shrinkage(%)

70+3 . 9

40+3 . 2

Figure 13

Conclusion:

Denier and draft values directly affect the shrinkage behavior of stretch denim. More

is the draft values, more will be shrinkage. The level of stretch-ability of yarn depends on

the given draft and fabric made of highly stretched yarns will relax more and hence the

shrinkage % of fabric will increase as there are more tensions on the yarns.

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Shrinkage due to varying Weft Count

No. of

ObservationsCount

Type of

Yarn

Denier +

DraftPicks/inch

Weave

Type

Shrinkage

Warp Weft

110

Single

Lycra 70+3.91 403/1 Z-

twill-6.5 -23

Spandex 70+3.91 403/1 Z-twill

-5 -22.13

Lycra

Slub 70+3.91 40

3/1 Z-

twill -4.12 -24.5

214

Single

Lycra 70+3.91 403/1 Z-

twill-6.1 -19.89

Spandex 70+3.91 403/1 Z-

twill-4.4 -21.13

LycraSlub

70+3.91 403/1 Z-twill

-4 -21.5

Table 7

Shrinkage (%) in Warp due to WeftCount

-7

-6

-5

-4

-3

-2

-1

0

Lycra

Spandex

Lycra

Slub

Shrinkage(%

10 Single

14 Single

Figure 14

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Shrinkage Due to varying Yarn Types

Trial No. CountFabricType

Denier+ draft

Picks/inchWeaveType

Shrinkage (%)

Warp Weft

1

10 Ne

Cottonlycra

70+3.91 403/1 Ztwill

-6.5 -23

2 Poly lycra 70+3.91 403/1 Ztwill

-6.1 -19.8

Table 8

Shrinkage (%) in Warp due to Yar

Type

-6.6

-6.5

-6.4

-6.3

-6.2

-6.1

-6

-5.9

Cotton lycra Poly lycra

S

hrinkage(%)

Figure 16

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Shrinkage (%) in weft due to Y

Type

-24

-23

-22

-21-20

-19

-18

Cotton lycra Poly lycra

Shrinkage(%)

Figure 17

Conclusion:

We concluded thatfabric made of cotton Lycra will shrink more than poly Lycra.

This is due to the reason that cotton has more affinity for the water than polyester so it

will absorb more moisture which results in more swelling of yarns; hence there is more

shrinkage in fabric.

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Shrinkage (%) due to varying Weave Type

No. of

Observations CountDenier

+ DraftPicks/inch

Weave

Type

Shrinkage (%)

Warp Weft

1

10 lycra 70+3.91 403/1 Z-

twill -6.5 -23

10

spandex70+3.91 40

3/1 Z-

twill -5 -22.13

10 lycraslub

70+3.91 403/1 Z-twill -4.12 -24.5

2

10 lycra 70+3.91 402/1 Z-twill -5.4 -18.7

10

spandex70+3.91 40

2/1 Z-

twill -4.7 -19.38

10 lycra

slub70+3.91 40

2/1 Z-

twill -4 -21

Table 9

Shrinkage(%) in W arp due to W

Type

-8-7-6

-5-4-3-2-1

0

10

lycra

10

spandex

10

lycra

slub

Shrinkage(%)

3/1 Z-twil

2/1 Z-twil

Figure 18

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Shrinkage(%) in W eft due to

Type

-2 5

-2 0

-1 5

-1 0

-5

0

10

lycra

10

spandex

10

lycra

slub

Shrinkage(%)

3/1 Z-twi

2/1 Z-twi

Figure 19

Conclusion:

The results shows that stretch denim fabric wuth 3/1 twill shrinks more than 2/1

twill denim as 3/1 twill has loose structure and more spaces.

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Shrinkage (%) due to Slub Yarns

Fabric

no.Count

Denier+

draftPicks

Weave

Type

Shrinkage (%)

Warp Weft

110

Lycra70+3.91 40

3/1 Z

twill-6.5 -23

210

Lycra

slub

70+3.91 403/1 Ztwill

-4.12 -24.5

Table 10

Shrinkage (% ) in w arp in Lycra an

-7

-6-5

-4

-3

-2

-1

0

10 Lyc ra 10 Lyc ra s lub

Shrinkage(%)

Figure 20

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Shrinkage (%) in weft in Lycra and Lycra

slub

-25

-24.5

-24

-23.5

-23

-22.5

-22

10 Lycra 10 Lycra slub

Shrinkage

(%

Figure 21

Conclusion:

Slub swells more when soaked in water. So due to more swellness,

shrinkage in yarn will be more.

PROCESSING SHRINKAGE

Samples were taken as for construction shrinkage

For finished fabric, 3HL washing was done at same conditions as in construction

shrinkage.

For studying washing conditions like temperature, washing cycles and washingtypes, 3HL was done.

But time was studied in Industrial washes.

Conditions:

Temperatur

e

40oC, 49oC, 60oC

Time 25 min, 40 min, 55 min

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INDUSTRIAL WASHES:

Rinse Wash:

Recipe

Chemicals Quality

Detergent (CP) 100ml

Softener (Belfacin) 200ml

Enzyme (Aquazyme) 50ml

Acid 400ml

Conditions:

Time 15min

Temperature

60~70oC

pH 6~7

Stone Wash:

Recipe

Chemical Quantity

Old Stone 5 kg

New Stone 5kg

Enzyme

( Valumax )150kg

Acid 400ml

Water 120 gallon

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Tint Wash:

Recipe:

CHEMICALS QUANTITIES

Direct Dye 0.5gm

Salt 1kg

Softener (NI) 60ml

Water 150 liter

Conditions:

Time 10min

Temperatur

e70oC

FABRICS USED FOR PROCESSING SHRINKAGE

FabricNo.

WarpCount

WeftCount

Ends/inch

Picks/inchWeaveType

F1 9.2 14/1+30D 64 48 2/1 RHT

F2 6.3 16/1+40D 68 44 2/1 RHT

F3 9 9/1+70D 64 45 2/1 RHT

Table 11

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Shrinkage (%)due to varying Washing Time

Fabric No.Weight (oz

per sq. yd)

Time (min)Shrinkage %

Warp Weft

F1

10.3 25 -0.9 -5.3

10.5 40 -1.5 -5.5

10.7 55 -1.8 -5.8

F2

11.4 25 -0.44 -10.1

11.5 40 -1 -10.5

11.8 55 -1.5 -10.9

F3

10.8 25 -2.4 -4.3

11 40 -2.8 -4.5

11.3 55 -3.9 -5

Table 12

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Shrinkage (%) in warp due to Washing ti

-5

-4

-3

-2

-1

0

25 40 55Time (min

Shrinkage(%)

F1

F2F3

Figure 22

Shrinkage (%) in weft due to washing time

-12-10

-8

-6

-4

-2

0

25 40 55Time (min)

Shrinkage(%

F1

F2

F3

Figure 23

Conclusion:

The comparison of shrinkage % at different washing times showsBy increasing the

washing time,shrinkage % tends to increase.

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Shrinkage (%) due to varying Temperature

Fabric

No.

Weight (oz

per sq. yd)

Temperature

(oC)

Shrinkage %

Warp Weft

F1

10.5 40 -0.4 -5.8

10.6 49 -1 -6.1

10.9 60 -1.9 -6.3

F2

11.6 40 -1.4 -10.8

11.7 49 -1.7 -11.4

11.8 60 -2 -11.9

F3

10.7 40 -2.4 -2.6

10.9 49 -2.6 -3.3

11 60 -2.9 -5

Table 13

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Shrinkage (%) in warp due to Washing

Temperature

-4

-3

-2

-1

0

40 49 60Temperature (

oC)

Shrinka

ge(%

F1

F2F3

Figure 24

Shrinkage (%) in weft due to Washing

Temperature

-14

-12

-10

-8

-6

-4

-2

0

40 49 60

Temperature (oC)

Shrinkage(%)

F1

F2

F3

Figure 25

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Shrinkage (%) due to different Washing Cycles

FabricNo. Weight (ozper sq. yd) WashingCycle

Shrinkage %

Warp Weft

F1

10.4 1 HL -0.37 -2.38

10.6 3 HL -1 -6.1

F2

11.53 1 HL -0.62 -4.69

11.7 3 HL -1.7 -11.4

F310.8 1 HL -1.5 -1.73

10.9 3 HL -2.6 -3.3

Table 14

Shrinkage (% ) in w arp due to Wa

Cycles

-3

-2.5

-2

-1.5-1

-0.5

0

1 HL 3 HL

Washing Cyc

Shrinkage(%

)

F1

F2

F3

Figure 26

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Shrinkage (%) in weft due to Washing

Cycles

-12

-10

-8

-6

-4

-2

0

1 HL 3 HL

Washing Cycles

Shrink

age(%)

F1

F2

F3

Figure 27

Conclusion:

The cmparison of shrinkage % at different washing cycles shows thatshrinkage % tends

to increase by increasing no. of washing cycles.

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Shrinkage (%)due to Washing Type

Fabric

No.

Weight(oz per

sq. yd)

Washing Type Shrinkage (%)

Warp Weft

F1

10.6 3 HL -1 -6.1

10.7 Industrial Wash -1.8 -5.8

F2

11.7 3 HL -1.7 -11.4

11.8 Industrial Wash -1.9 -11.8

F3

10.9 3 HL -2.6 -3.3

11.3 Industrial Wash -3.9 -5

Table 15

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Shrinkage (%) in warp due to Washing Types

-4.5

-4

-3.5

-3

-2.5-2

-1.5

-1

-0.5

0

3 HL Industrial Wash

Was hing Types

Shrinkag

e(%) F1

F2

F3

Figure 28

Shrinkage (%) in weft in Washing type

-14

-12

-10

-8

-6

-4

-2

0

3 HL Industrial Wash

Washing Type

Sh

rinkage(%)

F1

F2

F3

Figure 29

Conclusion:

As industrial washing compose of many washing types and cycles with varying

washing conditions, so sometimes the shrinkage values are higher for industrial wash.

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Shrinkage % due to different Industrial Washing Types

First Wash:

First wash may include any of these washing types depending upon desired look

and properties as demanded by the customer:

Rinse Wash

Rinse and Stone wash

Rinse and Stone wash with softener

Rinse and Stone wash with tint.

Rinse and Stone Wash with tint and softener.

FABRIC 1:

Washing

Type

Weight (oz

per sq. yd)

Shrinkage %

Warp Weft

Rinse Wash 10.2 0.4 -4

Rinse + Stone

Wash10.5 0 -6.6

Rinse + Stone

Wash +

Softener

10.6 -1.4 -7.9

Rinse +Stone

+ Tint Wash10.5 -1.3 -7.8

Rinse + Stone

+ Tint Wash +

Softener

10.5 -1.5 -7.9

Table 16

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Shrinkage in Fabric Samples due to

Different washing types

-10

-8

-6

-4

-2

0

2

RinseWash

Rinse+Stone

Wash

Rinse+Stone

Wash+Softner

Rinse+Stone+Tint

Wash

Rinse+Stone+Tint

Wash+Softner

Washing Types

Shrinkage

Warp

Weft

Figure 30

Second wash:

After first wash, any one or more of the following washes can be done according

to the look and properties demanded by the customer. The second wash includes:

Rinse and Bleach wash

Bleach wash with Neutralization

Bleach wash and Neutralization with Tint wash

Bleach wash and Neutralization with Softener

Bleach wash and Neutralization with Tint and Softener

Fabric 1:

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Washing TypeWeight (oz

per sq. yd)

Shrinkage %

Warp Weft

Rinse + Bleach Wash 9.9 -1.3 -4.4

Bleach Wash + Neutralization 10 -1.6 -4.3

Bleach Wash + Neutralization + Tint 10.3 -1 -5.5

Bleach Wash + Neutralization + Softener 10.4 -1.1 -5.4

Bleach Wash + Neutralization + Tint + Softener 10.5 -1.3 -6

Table 17

Shrinkage (%) in Fabric Sample due to Different Washes

-7

-6

-5

-4

-3

-2

-1

0

Rinse

+Blea

chWa

sh

Bleach+

Nuetr

alizatio

n

Bleach+

Nuetr

alizatio

n+Tint

Bleach+

Nuetr

alizatio

n+Softe

ner

Bleach+

Nuetr

alizatio

n+Tin

t+Softe

ner

Shrinkage(%)

Warp

Weft

Figure 31

Conclusion:

Shrinkage behavior is different for the different industrial washes depending the

procedure and combination of washes under which fabric go through. The different

washing types depend upon the customer requirement.

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Testing conditions:

Temperature 21oC 1oC

Relative humidity 65% 2%

Stretch % due to different Weave Type:

Fabric No. Weave type Stretch % Growth %

F1 2/1 Z Twill 17 3

F4 3/1 Z Twill 26.5 4.3

Table 18

Variation in stretch % due to weave

type

0

5

10

15

20

25

30

2/1 Z Twill 3/1 Z Twill

Weave type

Stretch

Figure 32

Conclusion:

3/1 weave will show more stretch ability than 2/1 weave due to loose structure of

3/1.

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7.1.2. Stretch % due to Draft and Denier:

FabricNo.

Count Draft +denier

Stretch%

Growth%

110

Lycra3.91+70 20.5 4

210

Lycra3.25+70 15.3 3

Table 19

Va riation in S tretch % du e to diff

Draft and Den ier

0

5

10

15

20

25

3.91+70 3.25+70Draft and D eni

Strech%

Figure 33

Conclusion:

By increasing the draft level, stretch % increases. The yarn having more draft of

lycra used in denim, will result in more stretchability.

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Variation in Stretching % due to Heat Setting

Heat setting temperature:180oC

Fabric No. Time (sec) Stretch % Growth %

F1

65 17 3

85 11.3 1.2

Table 20

Variation in stretch % with heat setting

times

0

5

10

15

20

65 85

Heat setting time (sec)

Stretch%

Figure 34

Conclusion:

By increasing the heat setting time, the stretch % decreases. The polymer

structure of lycra is set for longer duration.

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SKEWNESS

Denim is made up of twill weave. When denim garments are washed then a fault appears

in the fabric which affects the appearance and serviceability of garments. This fault is

known as skewness. Skew can be induced during the fabric manufacturing, dying,

finishing or the other operations where a potential exists for uneven distribution of

tensions across fabric width. Bow and skew are more visually displeasing in colored,

patterned fabrics such as plaids and horizontal stripes rather than in solid colors because

the contrast makes the distortion more prominent. These defects may cause sewing

problems in such fabrics and draping problems in finished products. In some cases a

specified amount of skew is needed, for example, to prevent trouser leg twisting.

Matching plaids from distorted patterns may create serious problems for the garment

manufacturer or home sewer.

Skew is defined as a fabric condition resulting when filling yarns are angularly

displaced from a line perpendicular to the edge or side of the fabric. Filling yarns

normally appear as straight line at right angles to the edge or side of fabric while

skewness is straight line distortion of marked filling yarn.

1. Positive skew: The right tail is longer; the mass of the distribution is concentrated

on the left of the figure. The distribution is said to be right-skewed.

2. Negative skew: The left tail is longer; the mass of the distribution is concentrated

on the right of the figure. The distribution is said to be left-skewed.

Testing method for measuring skewness:

Apparatus:

Measuring stick or steel tape

Rigid straightedge

Flat surface

Fabric inspection table

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Procedure:

Three samples from each fabric of 100 cm width were taken.

The samples were placed on a plain surface.

Filling yarn was marked across the width.

A straightedge was placed across the width perpendicular to selvedge such that it

coincided with the lowest point on the fabric at which the marked yarn meets one

of the selvedge edges.

The distance parallel to the selvedge between the straightedge and marked yarn

was measured and was recorded including the skew direction.

The skew percentage was calculated by the given formula:

Skew % right hand = skew distance (right) * 100

Fabric width

Skew % left hand = skew distance (left) * 100

Fabric width

Testing Results:

No. ofObs.

CountDenier +

DraftPicks/inch

WeaveType

Skew (cm)Skew movement

+3 ~ -3

110

Lycra 70+3.91 403/1 Ztwill

7.8 -1.2

210

Lycra 70+3.91 402/1 Ztwill

5 0.4

Table 21

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Skewness due toWeave Type

-1.5

-1

-0.5

0

0.5

3/1 Z twill 2/1 Z twill

Weave Type

Ske

w

Movement

Figure 35

Conclusion:

3/1 twill shows more skew as it is comparatively more loose weave then 2/1 twill.

Thats why filling yarns displace at the angular positions.

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