Effect on Tensile Strength after washing

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EFFECT OF WASHING ON TENSILE STRENGTH

OF DENIM FABRIC

A Thesis Submitted

in Partial Fulfillment of the Requirement

for the Degree of

Bachelor of Arts (Honours)

Scheme in

Fashion & Textiles

(Fashion Technology Specialism)

under the Supervision ofDr. C. W. Kan

by

Ching Man Yi

Institute of Textiles & Clothing

The Hong Kong Polytechnic University

April 2011


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I

ACKNOWLEDGEMENTS

First of all, I would like to express my academic supervisor,

Dr. C. W. Kan, for his supervision and constant encouragement

during my study, I would like to thank him for his many days

patient tutoring, Thank you, Dr Kan.

It is my honor to study the topic of about the properties for

different washing condition for tensile strength because it is

much related to our daily life and it should be more interest.

I would like the thanks all my friends. Especially, I am deeply

thankful for my friend, Becky Chan, Eve Chan, Eric Chan, Paul

Wong and Steve Tse, who have shared my hard and good time.

Finally, I would like to thanks my family for a many years caring

support.


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II

CERTIFICATE OF ORIGINALITY

I hereby declare that this thesis is my own work and that, to the best of my knowledge

and belief, it reproduces no material previously published or written, nor material that

has been accepted for the award of any other degree or diploma, except where due

acknowledgement had been made in the text.

_____________________________________________________________(Signed)

Ching Man Yi (Name of student)


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III


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V

CONTENT

Page

ACKNOWLEDGEMENTS I

HONOURS DECLARATION II

TURNITIN DECLARATION III

ABSTRACT IV

CONTENTS V

LIST OF TABLES IX

LIST OF FIGURES X

CHAPTER 1 INTRODUCTION 1

1.1 Background of Study

1.2 Objective

1.3 Scope of Study1.4 Chapter Summary

1

2

34

CHAPTER 2 LITERATURE REVIEW 5

2.1 Introduction 5

2.2 Denim 5

2.2.1 Material 5

2.2.2 Yarn of the Denim Fabric 11

2.2.3 Indigo Dye 12

2.3 Washing method on Denim Fabric 13

2.3.1 Background 13


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VI

2.3.2 Desizing of cotton 15

2.3.3 Stone Washing 15

2.3.4 Cellulase Enzyme Wash 16

2.3.5 Definition of Cellulase Enzyme 17

2.3.6 Cellulase Types 18

2.3.7 Principle and Effect of Enzyme 20

2.3.8 Controlling Parameters 22

2.4 Tensile Strength 23

CHAPTER 3 RESEARCH MECHODOLOGY 27

3.1 Introduction of Experimental Details 27

3.2 Experimental Arrangement 27

3.3 Fabric Specification 36

3.4 Cellulase Wash on Denim Wash 38

3.4.1 Apparatus 38

3.4.2 Preparation of the Specimen 42

3.4.3 Chemicals 42

3.4.4 Experimental Procedures 42

3.5 Tensile Strength 45

CHAPTER 4 RESULT & DISCUSSIONS 50

4.1 Effect of washing on tensile

strength of cotton fabric in warp

direction

50


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VII


strength of cotton fabric in weft

direction

56


strength of cotton spandex fabric

in warp direction

60


strength of cotton spandex fabric

in weft direction

65


strength of cotton fabric in warp and

weft direction

70


strength of cotton - spandex fabric

in warp and weft direction

75

4.7 Effect of washing on elongation to

break of cotton fabric in warp

direction

79


break of cotton fabric in weft

direction

84


break of cotton - spandex fabric in

warp direction

88


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VIII



weft direction

93


break of cotton fabric in warp and

weft direction

97



warp and weft direction

101

CHAPTER 5 CONCLUSION & RECOMMENDATION 106

5.1 Conclusion 106

5.2 Recommendation 108

REFERENCE 110


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IX

LIST OF TABLE

Page

Table 3-1 Experimental Arrangement 28

Table 3-2 Enzyme Wash Washing Recipe 31

Table 3-3 Enzyme Wash with Bleach Washing Recipe 32

Table 3-4 Enzyme Wash with Stone Washing Recipe 33

Table 3-5 Enzyme wash with Stone and Bleach Washing

Recipe

34

Table 3-6 Specification for Cotton Denim 37

Table 3-7 Specification for Cotton Spandex Denim 37


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X

LIST OF FIGURE

Page

Figure 2-1 Longitudinal view for cotton fiber 500X 7

Figure 2-2 Cross-Sectional view for cotton fiber 500X 7

Figure 2-3 Constitution of Cellulose Polymer 8

Figure 2-4 Constitution of Spandex fiber 10

Figure 2-5 Cross-Sectional view for Spandex Filament 10

Figure 2-6 The influence of pH on the activity of

cellulase enzyme

19

Figure 2-7 The influence of temperature of the

activity of a cellulase enzyme

19

Figure 2-8 The actions of cellulase enzymes on a

cellulase molecule

21

Figure 3-1 Side Loading Washing Machine 38

Figure 3-2 Hydroextractor Machine 40

Figure 3-3 Tumble Drier Machine 41

Figure 3-4 Instron, 4411 Tensile Tester 46

Figure 3-5 Grab Breaking Strength Test Specimens 46

Figure 3-6 Load Extension Curves in KES tensile test 49

Figure 4-1 Enzyme Wash In Warp Direction of Cotton

Fabric (Tensile Strength)

51

Figure 4-2 Enzyme Wash with Bleach In Warp Direction

of Cotton Fabric (Tensile Strength)

52

Figure 4-3 Enzyme Wash with Stone In Warp Direction


54


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XI

Figure 4-4 Enzyme Wash with Stone and Bleach In Warp

Direction of Cotton Fabric (Tensile

Strength)

55

Figure 4-5 Enzyme Wash In Weft Direction of Cotton


56

Figure 4-6 Enzyme Wash With Bleach In Weft Direction


57

Figure 4-7 Enzyme Wash With Stone In Weft Direction


58

Figure 4-8 Enzyme Wash With Stone and Bleach In Weft


Strength)

59

Figure 4-9 Enzyme Wash In Warp Direction of Cotton -

Spandex Fabric (Tensile Strength)

60

Figure 4-10 Enzyme Wash With Bleach In Warp Direction

of Cotton - Spandex Fabric (Tensile

Strength)

62

Figure 4-11 Enzyme Wash With Stone In Warp Direction


Strength)

63

Figure 4-12 Enzyme Wash With Stone and Bleach In Warp

Direction of Cotton - Spandex Fabric

(Tensile Strength)

64

Figure 4-13 Enzyme Wash In Weft Direction of Cotton -

Spandex Fabric (Tensile Strength)

66


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XII


of Cotton Spandex Fabric (Tensile

Strength)

67



Strength)

68



(Tensile Strength)

69

Figure 4-17 Enzyme Wash In Warp and Weft Direction of

Cotton Fabric (Tensile Strength)

70

Figure 4-18 Enzyme Wash With Bleach In Warp and Weft


Strength)

72

Figure 4-19 Enzyme Wash With Stone In Warp and Weft


Strength)

73


and Weft Direction of Cotton Fabric

(Tensile Strength)

74


Cotton - Spandex Fabric (Tensile

Strength)

75


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XIII



(Tensile Strength)

76



(Tensile Strength)

77


and Weft Direction of Cotton - Spandex


78

Figure 4-25 Enzyme Wash In Warp Direction of

Cotton Fabric (Elongation To Break)

80


of Cotton Fabric (Elongation To Break)

81



82


Direction of Cotton Fabric (Elongation To

Break)

83

Figure 4-29 Enzyme Wash In Weft Direction of


84



85



86


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Break)

88

Figure 4-33 Enzyme Wash In Warp Direction of

Cotton - Spandex Fabric (Elongation To

Break)

89


of Cotton - Spandex Fabric (Elongation To

Break)

90


of Cotton Spandex Fabric (Elongation To

Break)

91



(Elongation To Break)

92



Break)

93


of Cotton - Spandex Fabric (Elongation To

Break)

94


of Cotton Spandex Fabric (Elongation To

Break)

96


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97



98



Break)

99



Break)

100


and Weft Direction of Cotton Fabric


101



Break)

102




103




104


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and Weft Direction of Cotton - Spandex

Fabric (Elongation To Break)

105


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CHAPTER 1 INTRODUCTION

I

Chapter 1 Introduction

1.1 Background of Study

Denim Fabric, appeared in America in the late of 18 th century.

It is a cotton twill textile and the weft passes under two or

more warp fibers.

Denim was traditionally colored blue with the indigo dye. Indigo

dye is one of the dyestuffs with a distinctive blue color. For

the natural dye which come from some of the several species of

plant. But nowadays, the indigo procedure is synthetic and not

natural.

Denim is one of the most fashionable items in the fashion and

textile industry today. It can provide the durability and

different appearance effect for the garment when it is conduct

the different denim garment, and most people wearing the denim

garment.

Deterioration in the denim fabric of the textile product is often

important to the physical properties in deciding when the article

has reached the end of its using life [1].

Today, when the consumer buys the denim garment, they will

concern with the durability and physical use of the garment. They


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have the concept that denim can provide the good function for

long time to use. However, after the different washing condition

on the denim fabric, the percentage of shrinkage or the strength

of the fabric will also change.

In this project, all of the denim woven came from the same raw

manufacturer. And the denim washing was carried out under

different combinations of washing parameter, such as Enzyme Wash,

Enzyme wash with bleach, Enzyme wash with stone and Enzyme wash

with stone and bleach. All of these include 10, 20, 30, 40, 50,

60, 70, 80 and 90 minutes washing duration.

The relationship between different washing conditions that is

relative to the tensile strength has not been studied before.

Hence, the project focuses on the comparison of the different

washing condition on denim woven to the tensile strength.

1.2 Objective

1. To assess the effect of denim washing parameter denim fabric

on tensile strength.

2. Using the tensile strength method to compare the tensile

properties on different types of the denim washed fabric.

3. Using the elongation to break method to compare the breaking

properties on different types of the denim washed fabric.


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1.3 Scope of Study

In the study, the denim fabric was treated with different set

of condition with different combination: Enzyme Wash, Enzyme

wash with bleach, Enzyme wash with stone and Enzyme wash with

stone and bleach in 10, 20, 30, 40, 50, 60, 70, 80 and 90 minutes

washing times. After the treatment, tensile strength test will

be conducted to compare the difference between different washing

condition and their properties.

The physical properties will be compared the tensile strength

result in different type of washing condition. Tensile test, is

available for most types of the fabric no matter it is light fabric

weight or heavy fabric weight. Also, it is one of the simple,

relatively inexpensive and also can provide the fully

standardized. Furthermore, the user can very quickly to evaluate

the result.

In order to have a deeper understanding about issue of the washing

characteristic of denim fabric, it will be essential to carry

out the laboratory testing.

By carrying out the above experiment and evaluation, the

objectives of this study can be achieved.


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1.4 Chapter Summary

The project comprises of five chapters.

Chapter 1 Introduces background, objectives, significant and

scope of the study are introduced.

Chapter 2 contains a brief introduction of literature review as

well as the knowledge of denim fabrics, washing condition and

the physical testing especially tensile strength.

Chapter 3 provides experimental details which includes

experimental arrangement and the specifications of the denims

fabric. Besides, experimental procedures for the denim fabric

wash and evaluations of various physical properties of the

treated denims fabric.

Chapter 4 elaborates the results and discussions of evaluations

on different types on denims fabric for the tensile strength.

Chapter 5 gives conclusion of overall study and recommendation

of future studies on the washing on denim.


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CHAPTER 2 LITERATURE REVIEW

5

Chapter 2 Literature Review

2.1 Introduction

In order to carry the experiments of the denim washing, evaluated

of the different type of the denim fabric and analysis of the

data more effective, literature review was done. Fundamental

understanding the about the denim fabric include the material,

washing method, tensile strength properties and the enzyme

treatments also introduce.

2.2 Denim

2.2.1 Material

Denim is the heavy fabric with the wide fabric range there are

from 6 to 16 oz per sq. yard. Traditionally, it is usually weaving

from the 100% cotton, made from yarn dyed warp and undyed weft

yarn. The typical cotton construction is a warp - faced 3/1 right

hand side twill. As more dyed warp yarns are faced on one side

of the fabric, the face side of the denim is bluer. Meanwhile,

denim is a cotton twill fabric that dyed with the indigo. Indigo

is one of the natural dye come from the plant. As indigo only

can dye on the surface of the thread, when there have the stone

washes or the enzyme washes, the color will be faded. Hence the

irregular fading will appear on the fabric.


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The most commonly used material of the denim fabric is cotton

and spandex.

Cotton, which is a fiber that is unicellular, natural fibers

obtained from the boll from the cotton plant. The cotton fiber

is a single plant cell and the structure is complex.

Cotton fibers are staple length and the range is about 0.31 to

6.35 centimeters. And the length of the yarn is 2.22 to 3.18

centimeters long during manufacture.

The color of the cotton fiber varies from creamy white to dirty

grey, and never appear the true white.

Besides, it appears as a flat, twisted ribbon. Fiber tip, there

are less than one - quarter for the fiber length, tapers to a

cylindrical point. On the other, the end of seed is irregular,

having been torn from the epidermis for the cotton seed.

Moreover, it is the cellulose fiber there have the convolutions

along the and length and the kidney bean[2] cross-sectional

shape there are shown on the Figures 2-1 and 2-2


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Figure 2-1 Longitudinal view for cotton fiber 500X [3]

Figure 2-2 Cross-Sectional view for cotton fiber 500X [3]

Cotton fiber comprise have 91% cellulose, and other component

is include the small amount of protoplasm, pectin, waxes, fatty

substance, salts, water and organic acid [4].

Cellulose is the structural component of primary cell wall for

the green plants. Cellulose is not having taste, it is odourless,

and it is insoluble in water or most organic solvent, but it can

be broken down into glucose when treating it with the

concentrated acid at the high temperature.

Cellulose is a straight change polymer which linked glucose units

of at least 1500 units length and forming a linear polymer of


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-D-glucopyranose [5] and it is shown on the Figure 2 3.

The cellulose molecules group together to form microfibrils

which also like as the ribbon-like form, and a more or less

rectangular cross-section and in turn can form even larger

structural building blocks [6].

The hydroxyl group on the glucose for the chain from the hydrogen

bonds with oxygen molecules on the neighbor chain. Holding the

chains side by-side and form the microfibrils and there have the

high tensile strength. This is very important in the cell wall

when the microfibrils meshed onto the carbohydrate matrix.

Figure 2-3 Constitution of Cellulose Polymer [5]

Cotton fiber is one of the fiber there are cheap, light weight,

soft and easy to find the material.

It is widely use on the textile industry because for their

structure. According to the longitudinal view shown on the Figure

2-1, the shape is like the flat twisted tube there have the lumen.


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This structure can provide the circulation of the air that can

less clingy even the fabric is very heavy.

Even thought the fine of cotton has 13- 19 m , it also can provide

the stable in dimensional, good strength and the soft hand.

Cotton fiber is a hydrophilic fiber which has the high absorbency

of moisture, and the moisture content of cotton is about 8 9%,

Water can enter the inner space of the cotton. Cotton fiber can

absorbs the water from the water vapor emitted by the body, so

the skin does not become wet and let the people feel more

comfortable.

As cotton fiber is composed of cellulose, it can be attacked by

the mildew. Also, is also weakened by the resin chemical that

is used in finishing and the acid. But the more advantage is that

it cans highly resistance to alkalis.

Spandex fiber is the elastomeric fibers which can be stretched

repeatedly to at least twist their original length at the room

temperature.

Spandex manufactured which there are the fiber-forming substance

for the long chain synthetic polymer, and there at least 85% of

a segmented polyurethane [2], the generic group member shown as

Figure 2-4


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Figure 2-4 Constitution of Spandex fiber [2]

Spandex as a filament in the variety of deniers, the range is

from 20 5400 deniers. Normally, 20 210 deniers are used for

lightweight stretchable fabric, 140 560 deniers mostly for

medium stretchable. And 70 2240 are support the more

stretchable material such as the swimwear or other functional

garment.

Under the microscope, the monofilament spandex fiber appears

either square or the round appearance in the cross section there

shown as Figure 2-5.


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Figure 2-5 Cross-Sectional view for Spandex Filament [2]

Spandex fiber is a soft, pliable and supple with a hand much like

of a rubber band. When the chemical property of spandex is taking

into consideration, it has resistance to most of the acid or the

dry cleaning solvents but will damage by the alkalies. However

spandex fiber can be degraded by the sodium hypochloride chlorine

bleach so that it is not allow using it.

Generally speaking, spandex is less susceptible to deterioration

by the light and the chemicals. It is easier to handle because

it can allow machine washable and dry cleanable.

2.2.2 Yarn of the Denim Fabric.

Denim is the durable heavy fabric. Normally, the yarn used in

the denim weaving have the consider yarn count, the range is from

6 to 10 Ne. Ne is the unit of the yarn in the direct system

of cotton. Ne is defined by the number that of the certain length

per the standard weight of the yarn. When there are the higher

count number, the thinner the yarn and vice. Normally, in denim

fabric, warp yarn are thicker that the weft because weaving

process, the warp yarn need held in a higher tension.

The yarn used in denim is a simple yarn, that is describes as

a spun yarn based for the fiber length. Spun yarn is composed

of staple fibers that are twisted together. Moreover, sinmoke


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yarn can be described by the number of part it have. Based on

the description method, there have threes of yarn such as single

yarn, ply yarn and cord. And denim weaving is used for the single

yarn.

Single yarn, which is the product for the first twisting

operation, and is performed by the spinning machine which is

different to the ply yarn and cord yarn there have the second

and third twisting operation to combines two or more yarns

together. The strength of the yarn can be increase and so that

available for the denim fabric.

2.2.3 Indigo Dye

Indigo dye, which is the important of the natural dyes there have

been sustained to use. Indigo is a blue dye come from the certain,

such as from the Indigofera tinctoru in India. The group of

the colorants Indigo is one of the oldest known as the natural

dyes. The naturally is that occur material is indican, the

colorless glucoside of indoxyl[7]. When it is subjected to a

fermentation process, free indoxyl was generated by the enzyme

hydrolysis and the compound undergoes oxidation in air to indigo.

Due to indigo dye is not a soluble, so there is a challenging

dye. If it is necessary to dissolved, there should be undergo

the chemical change. Reduction transform the indigo into the


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white indigo when the fabric removed from the dyebath, the

indigo will quickly mix the oxygen and join it to an insoluable,

intensely to colored indigo.

In fact, environment will affect the color of indigo, as in the

vapour phase, the situation is approaches a monomolecular state,

and the indigo it shown the red. When it is pronounced positive

solvatochromism, in non polar solvents it should be violet.

And if in the polar solvents, there should be blue. Also, when

applied the fabric in Vat dye, it should be blue.

Indigo dye is imparting in a blue color and has a good wet fastness

property. Indigo have the moderate lightfastness, and even there

have the fading of the color, there without change of the color.

As there are available for using in the jeans and the denim item.

2.3 Washing method on Denim Fabric.

2.3.1 Background

Originally, all of the indigo jeans were stiff and uncomfortable

when first purchased, due to the finishing system used for denim

fabric. Normally, the warp yarns are dyed either in rope form

or slash form. The difference is the type of investment involved

and the result of the warp dyeing. Usually, rope dyeing will gives

a more even result between side to centre due to the dividing


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processes afterward. It is then followed by the sizing and

weaving.

Following weaving, the fabric is singed to burn off the surface

hair of the fabric, then padded through a finish bath containing

lubricants and the starch, and sent through a mechanical

shrinkage process.

After the desizing processing, the resulting of the fabric still

rigid. In previous time, the user would wear the jeans in normal

wearing or processed the jeans in a multiple home launderings

to improve the softness of jeans.

In order to exempt the extra processing by the customer, the denim

fabric manufacturers conduct the pre-washing jeans and abrade

the denim with stone or cellulose enzyme to achieve the softness

hand feel and the unique style.

Actually, if the manufacturers necessary to abrade the surface

of the denim fabric, they will select the stone washing or the

cellulose enzyme. For Stone washing, it is physically abrading

the fabric and cellulose enzyme is providing the chemical

abrasion.


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2.3.2 Desizing of cotton

Desizing is an important at the beginning stage in the processing

of cotton fabric. Waxes and synthetic water soluble sizes are

relatively simply removed from the fabric by scouring in the warm

water, and really would not respond to enzyme treatment alone.

Enzyme can remove the starch-based sizes, and the benefit is not

causing any physical chemical damage on the material. Even starch

and cellulose are both of long chains of glucose units linked

together, and they are different in the way that these units are

linked that amylases have no effect on cellulose and cellulases

have no result on the starch.

Starch is a combination of two similar carbohydrates of differing

molecular size and shape, amylopectin and amylase. Starch can

be mode to swell in water to form gel when it is meet the hot

water, thus there can remove starch successfully from the fabric.

As the progress of size removal can most conveniently be followed

by iodine coloration, the unhydrolysed starch can provide an

intense purple blue color, while glucose gives no color.

2.3.3 Stone Washing

Stone wash which the fabric washed along the pumice stones. The

denim fabric and the stone spinned together in the large

industrial washing machines. The degree of color fading is


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depending on the time that denim fabric and stone spinned

together. The ratio and size of the stone, liquor ratio and the

time setting, is very important for the stone wash.

There have some limitations for stone wash which is the cause

of the tear for the fabric. The increase the pollution of the

environment also caused by the stone wash because there have high

amount of disposition for the stone. Moreover, due to it require

removing the stone from the pocket, the labor cost will increase.

It is necessary to completely get rid of the stone, several

machine laundering is require in the process.

Although there have limitation of stonewashing, some factories

continuous to use because it can provide the vintage and used

look on the garment, and these varying degree for the abrasion

will appear in pocket side, seam, waistband and the body.

2.3.4 Cellulase Enzyme Wash

To minimize the unfavorable of the stonewashing, cellulase

enzyme is recommended to use. Enzyme wash is more environmental

friendly than the stone wash as the enzyme is the biodegradable

when can minimize the risk of pollution. It can also eliminate

through competition use of the stone and result in improperly

the quality of wastewater. In additional, cellulase enzyme can

reduce the overall processing time and complexity, gives a wider

abrasion shades [8]. As because it can control the appearance


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of the abrasion, it can prevent the wastage of the fabric and

increased up to 50% of the productivity [9].

On the other hand, cellulase enzyme washing provides more

softened the hand feel of the fabric and can remain the strength

of the fabric, when compared with the traditional stone wash.

In addition, cellulase enzyme washing can reduce abrasion

intensity on the fabric. Other benefit is that it can prevent

the formation of the fuzz and pills on the surface of the fabric,

increase the smoothness, luster, and uniformity of the color,

and improve the handle and durability.

2.3.5 Definition of Cellulase Enzyme

Enzyme is the protein structure comprising of polypeptide chains,

a varying complexity. Cellulase which is the class of hydrolytic

enzymes chiefly by Fungi. The major constituents of cellulase

are -1,4-gluconases and the chain is linked by peptide linkage.

There have some factory may distinguish from one enzyme to

another such as the odor what they linked, the presence or absence

from the metal and the particular amino acid present. Enzyme

is a water-soluble, enormously effective catalysts which permit

reaction and have low-energy path for the reaction to proceed.

In fact, enzymes are biological catalysts that can accelerate

the rate of simple chemical reaction without undergoing

permanent chemical change and thus can be re-used.


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Actually, cellulase is deactivated to stop the reaction when

after the enzyme treatment, and the enzyme only can acts on the

specific location of the specific substrate under specific

environment without having any effect on other components of the

system.

2.3.6 Cellulase Types

Cellulase Enzyme only has limited exhibit optimum performance

within the tight range for about temperature and pH. Thus,

enzymes involved in the enzymatic degradation of cellulase can

be classified by the optimum condition for their action,

such and temperature and pH. There are two types of cellulase,

that is neutral cellulase and acid cellulase, used for the

textile manufacturing. Neutral cellulase operates around pH

6.0 8.0 and Acid cellulase operates around pH 4.5 5.5. The

influence of pH on the activity of cellulase enzyme should on

Figure 2-6. Meantime, the neutral cellulase use 50 to 60 while

the acid cellulase only needs to use the lower temperature that

is about 45 to 55 . The influence of temperature on the activity

of a cellulase enzyme shown on Figure 2-7.


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Figure 2-6 The influence of pH on the activity of

cellulase enzyme [6]

Figure 2-7 The influence of temperature of the activity of a

cellulase enzyme [6]

It is very important to control carefully the processes


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parameters in enzymatic treatment for the denim fabric.

Actually, neutral enzymes require longer cycle times, less

aggressive but give no backstaining when it is achieve at the

same effect [6]. Acid enzymes have are faster reactions and more

aggressive when the result in more chemical abrasion and loss

for the strength.

On the other hand, neutral cellulase can provide the less extent

of back staining than the acid cellualse due to its lower

penetrating in the action. As acidic cellulase act in acidic

conditions, it favors re-deposition of removed indigo dye from

the warp yarn to the white yarn on denim fabric during the

enzymatic treatment. Because of this, there will occur the back

staining of the reverse side of the fabric. All of these side

effects lower the contrast of the unique of denim fabric.

2.3.7 Principle and Effect of Enzyme

The major constituent of cellulase are the -1,4-gluconases. It

actually consists of a complex mixture of acting enzymes. The

(1-4) linkages between adjacent repeat units in cellulase

polymer chain are the sites for catalytic hydrolysis by cellulase.

They catalyze the primary reaction of hydrolytically splitting

the -1,4-glycosidic linkages in cellulase chain molecule [10].

The main working principle of the acting enzymes is to cleave


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the long cellulase chains randomly to produce shorter chains and

finally glucose molecules are left. The actions of cellulase

enzymes on a cellulase molecule are shown in Figure 2-8.

Figure 2 -8 The actions of cellulase enzymes on a cellulase

molecule [6]

There have two major effect of cellulase on denim finishing is

that, first, give indigo-dyed cotton fabric and aged appearance

which as biostoning [11] and second is giving cotton fabric a

revived appearance by color brightening and softening. These

effects are caused by the synergetic action of cellulase and

mechanical agitation. The indigo dye particles remove along with

the cotton fiber. And the surface fibers for the denim fabric

are hydrolyzed by cellulase and the weaken fibers were removed


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during abrasion of the fabrics.

The stonewashing effects achieved by pumice stones can be

replaces by cellulase washing which chemically degrade cotton

in less abrasive way compare with the traditional stonewashing

to give out the washed - outlook.

2.3.8 Controlling Parameters

There have some major parameters for the cellulase washing of

the denim. They are temperature, pH, agitation, time, enzyme

dosage and liquor ratio. Other also includes the hardness of

water, properties of the buffer solution used and ionic

surfactants will also affect the enzymatic treatment. During

this study, pH, agitation, temperature and time are discuss in

the denim fabric [12].

pH

Different type of enzyme has its own pH tolerance. The

performance of its maximal activity depends on the range of pH

value used. Upon the optimum pH range, the internal structure

of enzyme will be changed permanently.

Agitation

Mechanical agitation creates more accessible sites for cellulase

attack either because of the increased diffusion into the fabric


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or the increased surface area after defibrillation.

Temperature

Enzymatic reactions increase with temperature within the optimum

temperature range where enzyme is stable and retains full

activity. Enzyme activity will decrease when deviation from the

optimum range.

Time

It depends on the liquid ratio, type of machine being used, the

materials of fabric and the desired effect on fabrics [12].

Longer the cellulase washing time will prolong the enzymatic

degradation of cellulase and also the time for further abrasion.

2.4 Tensile Strength

Tensile strength, it is one of the important properties in

relation to the measure the strength, and the modified for about

the grab test can be used the tensile fabric. The demonstration

about the strength for the fiber or the fabric structures is

regarded as the measure for the quality. Strength is very

important for the textile industry and most of the product will

conduct this test to ensure the quality. During measure the

quality, it is also include the flexibility, dye affinity

resilience or other more. Beside, the product quality will

depend on much of the end use. Such as the acid will reduce the


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24

cotton fiber strength.

The following will go to introduce the terminology and the

definition about tensile. [13]

Load

According to tensile, the application of a load is normally

expressed in grams weight or pounds weight, and the application

load to the specimen in an axial direction causes a tension was

developed in the specimen.

Breaking load

Breaking load means the load that the specimen breaks.

Stress

Stress is that when the qualities of fine and uncouth structure

have to be compared, suitable units must be chosen.

Mass Stress

The cross section of many type of fibers and the structure are

unequal, it is very difficult to measure about it. It is because

to abridge matters a dimension related to cross-section is used,

the linear density about the specimen. The linear density may

be articulated in denier o r tex count and mass stress then will

becomes the ration of the force applied to the linear density.


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Specific Strength or Tenacity

Tenacity that of a material is the mass stress at fracture and

alternative term of tenacity is specific strength.

Breaking Length

Breaking length is the length of the specimen which will just

break under its own weight when hung vertically.

Strain

When the load is applied to a specimen a assured amount of

stretching take place. This amount will differ with the initial

length about the specimen. The strain is that a term for used

to relate the stretch or elongation with the initial length.

Extension

There is the expressing the strain as the percentage get the

extension and the extension also refer to as the stain

percent.

Breaking extension

It is the extension about the specimen at the breaking point.

The load elongation curve

There are the really important curve is produced during the load

for the specimen is platted against the elongation. The curve

describe the behavior of the specimen from zero load and


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elongation up to the breaking point.

The stress strain curve

Some of the aims are more suitable to change the load-elongation

curve to a stress-strain curve, thereby enable more direct

comparisons to be made between different types of materials and

structure.


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CHAPTER 3 ___RESEARCH METHODOLOGY

27

Chapter 3 Research Methodology

3.1 Introduction of Experimental Details

In this chapter, the fabric specification, experimental

arrangements are describe. In additional, experimental details

including chemicals, recipes, apparatus and specimens

preparation and experimental principle are described.

3.2 Experimental Arrangement

Cotton and cotton - spandex denim fabric were treated with

different washing method such as Enzyme Wash, Enzyme Wash with

Bleach, Enzyme Wash with Stone and Enzyme wash with Stone and

Bleach. All of these washing methods were used with fixed

concentration and liquor ratio and applied with to different

washing duration for cotton and cotton spandex denim. The

experimental arrangement was shown on Table 3-1. Beside, the

details recipe and procedures of different denim washing method

was shown on Table 3-2, 3-3, 3-4 and 3-5 for enzyme wash, enzyme

wash with bleach, enzyme wash with stone and enzyme wash with

stone and bleach respectively.


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T able 3-1 Experimental Arrangement

Process Enzyme Wash

Chemical Neutral Enzyme

Time Range (mins) 10, 20, 30, 40, 50, 60, 70, 80, 90

pH Value 6.5

Liquor Ratio 50 : 1

Temperature ( ) 50

Amount 1% (OMG)

Process Enzyme Wash with Bleach


Chlorine

Time Range (mins) 10, 20, 30, 40, 50, 60, 70, 80, 90

pH Value 6.5

Liquor Ratio 50 : 1

Temperature ( ) 50

Amount 1% (OMG)

10% (OMG)


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Table 3-1 Experimental Arrangement (cont)

Process Enzyme Wash with Stone


Pumice Stone

Time Range (mins) 10, 20, 30, 40, 50, 60, 70, 80, 90

pH Value 6.5

Liquor Ratio 50 : 1

Stone Ratio 10:1

Temperature ( ) 50

Amount 1% (OMG)


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Table 3-1 Experimental Arrangement (cont)

Process Enzyme Wash with Stone and Bleach


Chlorine

Pumice Stone

Time Range (mins) 10, 20, 30, 40, 50, 60, 70, 80, 90

pH Value 6.5

Liquor Ratio 50 : 1

Stone Ratio 10:1

Temperature ( ) 50

Amount 1% (OMG)

10% (OMG)


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Table 3-2 Enzyme Wash Washing Recipe

Step Process Chemical Time

(Min.)

pH Liquor

Ratio

Temp.

(C)

Amount

(on weight

of garment)

1 Desizing Detergent 30 6.5 50:1 70C 1%

2 Rinse 5 Room

Temp.

3 Drain

4 Enzyme

Wash

Neutral

Enzyme

10 to

90

6.5 50:1 50C 1%

5 Rinse 5 Room

Temp.

6 Drain

7 Softening Cationic

Softener

15 6.5 50:1 40C 20%

8 Tumble

Drying

30 70C


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Table 3-3 Enzyme Wash with Bleach Washing Recipe


(Min.)

pH Liquor

Ratio

Temp.

(C)

Amount

(on weightof garment)


2 Rinse 5 Room

Temp.

3 Drain

4 Enzyme Wash Neutral

Enzyme

10 to 90 6.5 50:1 50C 1%

5 Rinse 5 Room

Temp.

6 Drain

7 Bleaching Sodium

Hypochlorite

5 6.5 50:1 70C 10%

8 Neutralize Sodium

Thiosulfate

10 6.5 50:1 Room

Temp

10%

9 Rinse 5 Room

Temp

10 Drain


Softener

15 5.5 50:1 40C 20%

12 Tumble

Drying

30 70C


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Table 3-4 Enzyme Wash with Stone Washing Recipe


(Min.)

pH Liquor

Ratio

Stone

Ratio

Temp.

(C)

Amount

(on weight

of garment)


2 Rinse 5 Room

Temp.

3 Drain

4 Enzyme Wash

Pumice

Stone

Neutral

Enzyme

Indonesia

Pumice

Stone

(3- 5 cm)

30 6.5 50:1 10:1 50C 1%

5 Rinse 5 Room

Temp.

6 Drain


Softener

15 6.5 50:1 40C 20%

8 Tumble

Drying

30 70C


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Table 3-5 Enzyme wash with Stone and Bleach Washing Recipe


(Min.)

pH Liquor

Ratio

Stone

Ratio

Temp.

(C)

Amount

(on weight

of

garment)


2 Rinse 5 Room

Temp

3 Drain

4 Enzyme

Wash

Pumice

Stone

Neutral

Enzyme

Indonesia

Pumice Stone

(3- 5 cm)

30 6.5 50:1 10:1 50C 1%

5 Rinse 5 Room

Temp

.

6 Drain

7 Bleachin

g

Sodium

Hypochlorite

5 6.5 50:1 30C 10%

8 Neutrali

ze

Sodium

Thiosulfate

10 6.5 50:1 Room

Temp

10%

9 Rinse 5 Room

Temp

10 Drain

11 Softenin

g

Cationic

Softener

15 5.5 50:1 40C 20%

12 Tumble

Drying

30 70C


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35

The following is going to describe the each process.

Desizing

It is a procedure for removal the sized applied when denim fabric

making in weft yarn. The fabric is dipped into a bath with the

detergent solution, following pH 6.5, liquor 50:1 and treated

70C for 30 minutes.

Rinse

When completed each of the each of the washing processes, there

is still have liquid on the surface to be cleaned up, the rinse

procedure first requires a cleaning step.

Bleaching

For this process, it is not necessary add the pumice stone and

by using the oxidative bleaching agent such as the Sodium

hypochlorite. Sodium hypochlorite is a normally as it have the

convenient and quick. Some of other agent used is sodium

percarbonate and sodium perborate.

Neutralize

Suitable neutralizations for after bleaching process are very

important in order to get rid of fabric strength, bad smell, or

skin irritation and yellowing of the garment.


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Softening

Denim fabric is very critical for the softening. Subject to denim

is a heavy material in compare with other type of the fabric,

and so is necessary to softening. But it is to care the

discoloration of denim such the shade change of the color or loss

of whiteness.

Tumble drying

When completed all of the wet process, it is necessary to have

the tumble drying to ensure the garment is whole dry, the time

normally is about 45 minutes to 60 minutes.

3.3 Fabric Specification

Cotton and cotton spandex denim fabric were pre-conditioned in

standard environment according to ASTM d1776 before measuring

the fabric specification. Beside, the specifications were

collected by using the standard method.

The specification of cotton and cotton spandex denim fabric were

shown on Table 3-6 and Table 3-7


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Table 3-6 Specification for Cotton Denim

Composition 100% Cotton

Fabric Construction 3/1 Right Hand Twill

Weight 10 oz/yd 2

Warp Weft

Fabric Density 66 ends/inch 51 ends/inch

Yarn Count 7.5s 10s

Table 3-7 Specification for Cotton Spandex Denim

Composition 99% Cotton 1% Spandex

Fabric Construction 3/1 Right Hand Twill

Weight 10 oz/yd 2

Warp Weft

Fabric Density 70 ends/inch 57 ends/inch

Yarn Count 7.5s 12s + 20D

According to the specification table, cotton and cotton spandex

denim fabric are very similar. The major different is the cotton

spandex denim fabric have 1% spandex twist in weft yarn and

according to this reason, there will affect the performance of

washing method and the tensile strength result.


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3.4 Cellulase Wash on Denim Wash

3.4.1 Apparatus

Side Loading Washing Machine

Cellulase wash by using the Side Loading Washing Machine as shown

in Figure 3-1

Figure 3-1 Side Loading Washing Machine

For all of the cellulase denim washing, this was carried out by

150 lb side washing machine. They were washed basically on

controlled parameters and conditioned environment.

The Side Loading Washing Machine which was used had horizontal


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39

and drum-type structure and the inner drum made for about the

stainless, and so that it could easily to be operated with

selected, temperature and the rotation speed. Besides, there had

not the central agitator which uses gravity and the side mounted

paddles to stir up the cloth. When the door was closed, it would

remain lock mechanically until the washing cycles are finished.

For the industrial washing machine, there have the

semi-automatic machine, the worker can choose the manual method

or the automatic method for handle machine. The moving for the

machine roller has divided into two different directions. After

the machine is toward left to roll, they will stop a few minutes.

Afterward, it will change to opposite direction to move and also

stop a few minutes. These steps will continuous to conduct until

the washing cycle complete.

It is suitable for various washing, for example, stone wash,

enzyme wash, bleaching and dyeing.

Hydroextractor

Hydroextractor is a machine which mostly used in the textile

processing industry. It has a heavy basket spinning at great

speeded and it uses high speed spinning to squeeze water from

the laundry. The speed of the machine can attain over 1500 RPM.

Besides, if the heavy material such as the jeans, sweater or

jacket is place on the hydroextractor for squeezed before drying,


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the time of drying can reduce by one-half, so that it can save

the drying time, energy and also can reduce the damage of the

material.

The working procedure is the wet material is located in the

extractor, which has a wall of perforated metal, normally

stainless steel. The internal drum rotates at the high speed thus

throwing out the water containing in it. The Hydroextractor

Machine is shown on Figure 3-2

Figure 3-2 Hydroextractor Machine

Tumble Drier

The tumble drier, with is used to remove moisture from a load

for the textile material, normally shortly after they are cleaned


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41

in a washing machine.

It is a front loading open pocket with inner stainless steel

basket machine, the inner stainless steel basket is fitted with

stainless steel paddles to ensure the tumbling effect smooth.

For the tumble drier there have two types of drying method that

is steam and electricity, and both types are suitable for the

industrial use.

The Tumble drier also can control the rotation direction,

temperature and timing. The Tumble Drier machine shown on Figure

3-3

Figure 3-3 Tumble Drier Machine


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42

3.4.2 Preparation of the specimen

As prevent the edge of the material slippage during washing

process, lock stitch in necessary before washing.

All of the specimens were conditioned under standard atmospheric

pressure at 65% 2% relative humidity and 21 1 for at least

24 hours prior to denim washing.

3.4.3 Chemicals

A neutral enzyme is a powder form was used in enzymatic treatment

on denims. Moreover, detergent, sodium hypochlorite, sodium

thiosulfate and cationic softener would add on the following

steps.

Beside, the entire chemical added was depends on the weight of

the garment.

3.4.4 Experimental Procedures

In denim, garment washing is done to produce effects such as the

color fading with or without patchiness, crinkles, depilling or

stabilizes dimension etc. Normally, the process of garment

washing involves stage like product evaluation and preparation

desizing, braiding, bleaching, anti-chloring / post scouring,

over dyeing (optional), softening, hydro-extracting and tumble

drying. Various process effects for the special products can be


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43

obtained by using combination of these procedures. Different

processing parameters can be set for each stage to enhance and

improve the effects.

All of the specimens were weight and the value used to calculate

the required of the chemical amount on weight of goods and also

the required volume of water for the denim washing.

Desizing

Sizing is the need for the weaving but is an obstacle for the

dyeing. The first processes by which we remove sizes on the

garment wash as known as desizing. Desizing can removal of size

applied when the denim fabric making in weft yarn. For this

project, it is used the detergent solution. And some factory will

containing polyacrylic acid and is more effectively removed by

using soda ash. The principle steps in the desizing procedure

are firstly, wetting out with the suitable wetting agent, and

steeping for affecting the swelling and softening, and following

is rising thoroughly in overflowing water.

The method of desizing of starch-sized textiles is described.

In this relationship, the denim fabric is dipped into a bath

containing with the enzyme mixtures as well as the detergent

solution, having a pH about 6.5 and the liquor ratio is 50:1,

following then treated at 70C for 30 minutes.

The next processed would following when desizing completed.


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44

Rinse

And the coming step is rinse, which is removing the detergent

on the fabric. After, it Drain away the solution.

Enzyme Wash

Enzyme Wash, which is one of the important step of the garment

wash. It is a bio-catalytic method wherein an ultra-soft handle

effect can be produced on denim. This effect of enzyme causes

the loss of surface fibre, which improves surface smoothness and

softness of the fabric. The method of enzyme wash of textiles

is described. The denim fabric is dipped into a bath containing

with the with the mixtures as well as the neutral enzyme, having

a pH for 6.5, the liquor ration is 50, following then treated

at 70C and run for 10 minutes to 90 minutes.

During the enzymes process, the temperature and pH control is

very important. For temperature, if there are above the optimum

temperature, the coil structure of enzyme will destroy and the

activity will decrease. Moreover, the pH value is that the enzyme

with board pH range for better consistency of the result. This

is a time for add the pumice stone, and add in this time is that

can speed up the rate of the abrasion. For this project neutral

enzyme is used for. And anionic surfactant may be harmful to the

enzyme, non-ionic detergent should be used. The degree of

decrease in activities of the enzyme may vary from on to each

other.


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Bleach Washing

Sodium Hypochlorite is used in this project, because it is a

slightly yellowish solution and also a clear on the odor.

In this relationship, the denim fabric is dipped into a bath

containing with the Sodium Hypochlorite, having a pH about 6.5

and the liquor ratio is 50:1, following then treated at 70C for

5 minutes.

When completed the denim washing, such as Enzyme Wash, Enzyme

wash with bleach, Enzyme wash with stone and Enzyme wash with

stone and bleach, the tensile strength analysis will conduct.

3.5 Tensile Strength

Tensile properties of specimens were measured by INSTRON, 4411

TENSILE TESTER and shown in Figure 3-4. And the test was followed

the ASTM 5034 09, standard test method for breaking strength

and Elongation of Textile Fabric (Grab Test) for evaluation the

tensile strength properties of denim fabric.


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46

Figure 3-4 Instron, 4411 Tensile Tester

Specimen was cut 4 x 6 inches, so that the direction of test is

in the longer direction, shown on Figure 3-5

Figure 3-5 Grab Breaking Strength Test Specimens


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47

The Flat Kaw one inch on a side and three inch apart at the start

of the test are used to clamp the fabric. When the jaws were

separated, the through-going yarns clamped in both jaws were

subjected to tension. Moreover, because of the interaction of

warp a nd weft yarn with attendant frictional forces a fabric

assistance effect develops and yarns adjacent to those actually

clamped in the jaws will help to support the load. Then, the grab

strength test mostly produces higher strength values of the

fabric [14].

The procedure was that the upper jaw for about the tester was

attached to a steel bar of proper capacity and design, so at full

load its deflection is completely elastic, and negligible. When

the force was used, the result comparative voltage change

produced by the gage was amplified and recorded as a direct

measure of the specimen load. The upper jaw moves an almost

imperceptible amount even at maximum load, the pulling jaw

actually elongates the test specimen at a constant rate, and the

instruments, and it was constant rate of extension tester.

The Instron tester that was various capacity load recording

cell can be installed so the specimens with a wide range of

breaking strength.

The Rate of loading or extension can influence the ultimate

breaking strength, so ASTM specifies the rate, and more property,

the time to break. The Specified pulling jaw speed is 12 1/2


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48

inches per minutes and the yarn breakage will break within 20

3 seconds from the start of test.

For about the servo-mechanism, the lower or pulling jaw can be

moved at rates ranging from 1.0 to 20 inches per minutes. Gear

backlash was reduced to a minimum so that repeated stress

diagrams can be obtained. The jaw was driven downwards until a

selected load or strain develops, and then the jaw travel

direction was automatically reversed so that the load was removed.

The strain gage force recording cell is completely free of

inertia, so the tensile forces which develop in the test specimen

were immediately recorded.

For about the tensile testing machines, the elongation axis

for the automatic load elongation recorder runs at a constant

speed, and so the direct measure of jaw separation results.

The recorded jaw separation of flat jaw can be taken as a direct

measure of the specimen s elongation. Such in a tensile test,

the gauge length at the start of the test was three inches. At

the instant of rupture, if the jaw moved 0.6 inches, the breaking

percent elongation could be calculated as (0.6 3) x 100 = 20%.

There might be slight elongation of the ends of the specimen held

in each jaw, it was called the jaw penetration, which might make

the gage length slightly greater than three inches. And for the

true elongation correspondingly slightly less, but this error

was usually negligible and was ignored in the calculation [14].


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49

The tensile properties was measured by plotting the force

extension curve between zero and a maximum force of 500gf/cm,

the recovery curve as the specimen was allowed to return to its

original length which is also plotted to give the pair of curves

shown in Figure 3-6.

Figure 3-6 Load Extension Curves in KES tensile test


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CHAPTER 4 ______ RESULTS & DISCUSSION

50

Chapter 4 Results & Discussion

The result of denim fabric under different washing methods and

analyze the warp and waft yarn its strength and impacts after

washing will be discussed in details.

4.1 Effect of washing on tensile strength of cotton fabric in

warp direction

Effect of enzyme washing on the tensile strength of cotton fabric

in warp direction

The data of enzyme wash for warp cotton fabric is shown in Figure

4-1.

In terms of warp yarn strength after washing, its strength tends

to be weaker after washing compare with the original.


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Figure 4-1 Enzyme Wash In Warp Direction of Cotton Fabric

(Tensile Strength)

According to the Figure 4-1, the yarn strength tends to be weaker

after longer time of washing. However, the yarn strength becomes

stronger in the raising time in 50 minutes washing. The possible

explanation could be the yarn after washing become higher level

of shrinkage. Therefore the higher density between the yarns as

the results of yarns could share the loading and withstand

tensile force, as we can see that the washing time from 40 minutes

to 50 minutes could withstand tensile force from 767.87(N) to

841.78 (N) approximately increased 10% tensile force.

However, after longer time of rinsing time. The enzyme chemical

further to damage of the yarn. The yarn strength tends to be weaker

after 60 minutes of washing. When the washing time of 50 minutes

to 60 minutes significantly decrease the tensile strength from


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52

841.78(N) to 780.75(N) and so it is decease about 7% of tensile

force.

Beside, the yarn strength tend to be stable from 60 minutes to

90 minutes, as the tensile strength in 60, 70, 80 and 90 minutes

washing is 780.75 (N), 779.50 (N), 785.5 (N)and 785.77

(N)respectively.

Effect of enzyme with bleach washing on the tensile strength of

cotton fabric in warp direction

Figure 4-2 shows the effect of the enzyme wash with bleach in

the warp direction cotton fabric.

.

Figure 4-2 Enzyme Wash with Bleach In Warp Direction of


Based on Figure 4-2, the fabric before wash and the fabric after


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53

washing in 10 minutes have significantly change in terms of

tensile strength from 879.96(N) to 794.18 (N) approximately

change in 10% in tensile strength.

It is surprise to find that the tensile strength from to 10 to

90 minutes has an up and down tends. However, the tends is that

the tensile strength is become stronger after longer times of

washing.

The fabric before washing and the fabric after washing in 90

minutes the tensile strength decrease from 879.96(N) to 871.05

(N) approximately 1 percent. The possible explanation could be

the yarn after washing become higher level of shrinkage.

Therefore the higher density between the yarns as the results

of yarns could share the loading and withstand tensile force

Effect of enzyme with stone washing on the tensile strength of

cotton fabric in warp direction

The information about enzyme wash with stone in the warp

direction of cotton fabric is shown on Figure 4-3.


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54

Figure 4-3 Enzyme Wash with Stone In Warp Direction of


For Figure 4-3, it is surprise to find that the tensile strength

that before wash and the fabric after washing in 10 minutes from

879.96 (N) to 946.75 (N) approximately increase in 7.6%. This

result is abnormal, this is because in normal situation, the

fabric before wash should be stronger than that of fabric after

washing in term of tensile strength.

In addition, it was find that that the tensile strength from to

10 to 90 minutes has an up and down tends. However, the washing

time of 50 minutes to 60 minutes significantly decrease the

tensile strength from 928.68 (N)to 857.18(N)and so it is decease

about 7% of tensile force.

After 50 minutes of rinsing time. The enzyme chemical and stone

further to damage of the yarn. The yarn strength tends to be weaker

after 60 minutes of washing.


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55

From 60 minutes to 90 minutes, the yarn strength tend to be stable,

as the tensile strength in 60, 70, 80 and 90 minutes washing is

857.18 (N), 863.89 (N), 868.27(N)and 850.20 (N)respectively.

Effect of enzyme with stone and bleach washing on the tensile

strength of cotton fabric in warp direction

The data for enzyme wash with stone and bleach in the warp

direction of the cotton fabric is shown on Figure 4-4.

Figure 4-4 Enzyme Wash with Stone and Bleach In Warp Direction


According to above Figure 4-4, the fabric before wash and fabric

after 10 minutes wash is slightly change in terms of tensile

strength from 879.96(N) to 855.48 (N) approximately change in

about 2% in tensile strength.

In addition, the yarn strength after washing in longer time has


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56

significant decrease in terms of tensile strength.

In additional, it was observe that that the tensile strength from

to 10 to 40 minutes has an up and down tends and from 40 to 90

minutes, it has major decline for tensile strength.


weft direction

Effect of enzyme washing on the tensile strength of cotton fabric

in weft direction

For the information of effect of Enzyme Wash in the weft direction,

the results are shown in Figure 4-5.

Figure 4-5 Enzyme Wash In Weft Direction of Cotton Fabric

(Tensile Strength)

Based on Figure 4-5, the fabric before wash and the fabric after


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57


tensile strength from 442.73(N) to 371.09(N) approximately


Fabric after enzyme wash in different washing time, tend to be

stable in terms of tensile strength. However, from 50 minutes

to 90 minutes, it was found that the tensile strength become

weaker.

Effect of enzyme with Bleach washing on the tensile strength of

cotton fabric in weft direction

The effect of enzyme wash with bleach in the weft direction of

cotton fabric is shown on Figure 4-6.

Figure 4-6 Enzyme Wash With Bleach In Weft Direction of


From Figure 4-6, the fabric before wash and the fabric after


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58




Moreover, it was find that that the tensile strength from to 10

to 90 minutes has an up and down tends and from 70 to 80 minutes,

it has major decline for tensile strength. From 80 to 90 minutes,

it has slightly increased in terms of tensile strength.


cotton fabric in weft direction

Figure 4-7 shows the data about the effect of enzyme Wash with

stone in the tensile strength in the weft direction of cotton

fabric.

Figure 4-7 Enzyme Wash With Stone In Weft Direction of



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59

According to Figure 4-7, the fabric before wash and the fabric

after washing slightly change in tensile strength.

From 10 to 60 minutes have down tends. From 60 to 70 minutes,

tensile strength becomes stronger. But after 80 minutes, the

tensile strength becomes weaker than 70 minutes.

Effect of enzyme with stone and bleach washing on the tensile

strength of cotton fabric in weft direction

Effect of enzyme wash with stone and bleach in the weft direction

of cotton fabric is shown on Figure 4-8.

Figure 4-8 Enzyme Wash With Stone and Bleach In Weft Direction


From Figure 4-8, the fabric before wash and the fabric after




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60


From 10 to 70 minutes, tend to be stable in terms of tensile

strength. However, from 70 minutes to 80 minutes, it was found

that the tensile strength drop down suddenly.

4.3 Effect of washing on tensile strength of cotton spandex

fabric in warp direction

Effect of enzyme washing on the tensile strength of cotton -

spandex fabric in warp direction

Figure 4-9 shows the data about the effect of Enzyme Wash in warp

direction of cotton spandex fabric.

Figure 4-9 Enzyme Wash In Warp Direction of Cotton - Spandex


For the data in Figure 4-9, it shown the fabric before wash and


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61

the fabric after washing in 10 minutes have significantly change

in terms of tensile strength from 837.18(N) to 784.16 (N)

approximately change in 6% in tensile strength.

Further to 10 minutes washing declining the tensile strength when

compared with the fabric before washing, In 20 minutes washing

time. It is further declining the tensile strength in compare

with 10 minutes of washing time. It also occurred an up and down

tends between 10 minutes to 90 minutes washing. In addition,

longer time of washing have more harmful impacts in terms of

tensile strength. People may judge that warp yarn without spandex

will not be affecting the tensile strength. However, as we all

know fabric is weaving together, while weft yarn weak will result

in interdependency issues which make warp yarn tends to be easy

to break.


cotton - spandex fabric in warp direction

Enzyme wash with bleach in warp direction of cotton - spandex

is shown on Figure 4-10.


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Figure 4-10 Enzyme Wash With Bleach In Warp Direction of

Cotton - Spandex Fabric (Tensile Strength)

For Figure 4-10, the fabric before wash and the fabric after

washing in 10 minutes have slightly change in terms of tensile


5% in tensile strength.

It was occurred an up and down tends between 10 minutes to 90

minutes washing. From 70 to 90 minutes, the tensile strength

becomes stable.

Sodium hypochloride chlorine bleach can damage the spandex fiber,

as known as the fabric is weaving together, when the weft yarn

weak will result in interdependency issues which allow the

strength of warp yarn weaker.


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Effect of enzyme with Stone washing on the tensile strength of

cotton spandex fabric in warp direction

Enzyme wash with stone in warp direction of cotton - spandex data

is shown on Figure 4-11.

Figure 4-11 Enzyme Wash with Stone In Warp Direction of


According to Figure 4-11, it was astonish to find that the tensile

strength that before wash and the fabric after washing in 10

minutes from 873.18 (N) to 870.42 (N) approximately increase in

4%. This outcome is irregular as because in neutral circumstances,

the fabric after washing should be weaker than the fabric before

wash in term of tensile strength.

Moreover, from 10 to 90 minutes, it was occurred the up and down

tends. However, we observe that the washing time of 40 to 50

minutes have significantly decrease the tensile strength from


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820.49 (N) to 762.95 (N) and it is decrease about 7% of tensile

force. In additional, for 60 to 70 minutes, it also have

significantly decrease in strength from 838.38 (N) to 756.69 (N)

and it is decrease about 10% of tensile force.

Effect of enzyme With Stone and Bleach washing on the tensile

strength of cotton spandex fabric in warp direction

Enzyme wash with stone and bleach in warp direction of cotton

- spandex data is shown in Figure 4-12.

Figure 4-12 Enzyme Wash with Stone and Bleach In Warp Direction

of Cotton - Spandex Fabric (Tensile Strength)

For the Figure 4-12, it was found out that the fabric before wash

and the fabric after washing in 10 minutes have slightly change

in terms of tensile strength from 837.18(N) to 793.82 (N)

approximately change in 5% in tensile strength.


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In 10 minutes washing declining the tensile strength when

compared with the fabric before washing, in 20 minutes washing

time. It is further declining the tensile strength in compare

with 10 minutes of washing time. For 10 minutes to 90 minutes,

it occurred as unstable trend. Moreover, for longer time washing

have more damage impacts in terms of tensile strength.

As known as the fabric is weaving together, the weft yarn weak

will result in interdependency issues which allow the strength

of warp yarn weaker, since of this when the sodium hypochloride

chlorine bleach damage the spandex fiber in weft yarn, it also

will affect the warp yarn

4.4 Effect of washing on tensile strength of cotton spandex

fabric in weft direction

Effect of enzyme washing on the tensile strength of cotton

spandex fabric in weft direction

Enzyme wash in weft direction of cotton - spandex is shown on

Figure 4-13.


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As shown in Figure 4-13, the fabric before wash and the fabric

after washing in 10 minutes have much change in terms of tensile

strength from 375.42 (N) to 320.84 (N) approximately change in


Fabric after enzyme wash in different types of washing time, tend

to be stable in terms of tensile strength. However, from 70

minutes to 90 minutes, it was found that the tensile strength

become weaker, there is about 263.53 (N) to 255.07 (N).


cotton spandex fabric in weft direction


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Figure 4-14 shows the effect of the enzyme Wash with Bleach for

weft direction of cotton - spandex Fabric.

Figure 4-14 Enzyme Wash with Bleach In Weft Direction of


For the Figure 4-14, the fabric before wash and the fabric after

washing in 10 minutes have much change in terms of tensile

strength from 375.42 (N) to 320.84 (N) approximately change in


From 10 to 90 minutes, it have slightly up and downs tends, but

the trend is stable and when there have longer time washing, there

have more damage impacts as the strength of the fabric become

weaker.

Moreover, weft yarn twisted with the spandex fiber, and spandex

could damage by the sodium hycoloride chlorine bleach, so that

the strength result would become weaker.


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cotton spandex fabric in weft direction

Enzyme wash with stone in weft direction of Cotton - Spandex

information is shown on Figure 4-15.

Figure 4-15 Enzyme Wash with Stone In Weft Direction of


In accordance with Figure 4-15, it can observe that the fabric

before wash and the fabric after washing in 10 minutes have

slightly change in terms of tensile strength from 375.42 (N) to

345.81 (N) approximately change in 8% in tensile strength.

In terms of weft yarn strength after washing, its strength tends

to be weaker after washing in overall.

From 10 minutes to 80 minutes, there have a little up and downs

tend. When 80 minutes to 90 minutes, there have significant drop

down, it is 321.78 (N) to 279.79 (N) and approximately change


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in 13% in tensile strength.

Effect of enzyme with stone and bleach washing with stone and

Bleach on the tensile strength of cotton spandex fabric in weft

direction

Enzyme wash with stone and bleach for weft of cotton spandex

Data is shown on Figure 4-16.

Figure 4-16 Enzyme Wash With Stone and Bleach In Weft Direction

of Cotton - Spandex Fabric (Tensile Strength)

For Figure 4-16, the fabric before wash and the fabric after

washing in 10 minutes have large change in terms of tensile



From 10 to 20 minutes, it is 312.88 (N) and 312.43 (N),and very

stable. When it is 30 minutes, the tensile strength increase


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slightly. From 30 to 90 minutes, the trends are to tend to become

weaker. It is because there for have a longer washing time and

so there have more damage impacts in terms of tensile strength.

Moreover, sodium hypochloride chlorine bleach damage the spandex

fiber is one factor carry out the weft yarn will became weaker

in tensile strength result.


warp and weft direction

Effect of enzyme washing on the tensile strength in warp and weft

direction of cotton fabric

Enzyme wash in warp and weft direction of cotton fabric is shown

on Figure 4-17.

F igure 4-17 Enzyme Wash In Warp and Weft Direction of



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In relation to Figure 4-17 is used to unite warp direction and

weft direction for analysis, and it can allow to read the overall

of the fabric for tensile properties.

The warpwise tensile was greater that the weftwise strength. And

the washing sample is slightly weaker than the original.

For the Enzyme washed sample, all of the warpwise and weftwise

tesnile strength were smaller than those of the original sample,

and decrease gradually as the processing time from 10 minutes

to 90 minutes.

Moreover, all of the warpwise and weftwise tesnile strength have

slighly up and down trend, according this information, it can

see the alter of warpwise and weftwise is very similar.

Effect of with bleach enzyme washing on the tensile strength in

warp and weft direction of cotton fabric

Enzyme wash with bleach in warp and weft direction of cotton

fabric is shown on Figure 4-18.


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Effect on Tensile Strength after washing