Group MembersM Usman Azeem 3609Syed Qutaba Bin Tariq 3607Arif Hussain Jauto 3594M Saqlain Chishti 3577Jahangir Khan Bazai 3617Jaleel Ahmed 3606

Title Study of pretreatment & Dyeing recipies and role of axillaries used in these processes

Project Supervisor

Miss Lubna Syed

Study program

Section

BS(Textile Engineering)

Fall-06

Balochistan University of Information Technology, Engineering and Management Sciences

DEDICATION

We dedicate our project to our great parents.

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ACKNOWLEDGEMENT

Our first experience of project has been successfully, thanks to the support staff of many friends & colleagues with gratitude. We wish to acknowledge all of them. However, we wish to make special mention of the following:First of all, we thankful to almighty ALLAH for the successful completion of this project. Who gave us strength and power to attain our target. After that we are thankful to our project supervisor Ms. Lubna Syed under whose guideline we were able to complete this project. We are wholeheartedly thankful to her for giving us her value able time & attention & for providing us a systematic way for completing our project in time.We are thankful to H.O.D Dr. Fahim Udin and Chairman Mr. Ali Asgher and all other staff for providing their assistance and guidance at different stages during this project. We are also thankful to the Sapphire Mills ltd. who allows us in their unit to perform our project experiments.We are also very thankful to our vice chancellor Engr. Farooq Ahmed Bazai who gave us an opportunity to present this project.

All Group Members

Table of contents

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Summary of Project 7

Chapter no 1

Introduction to fibers 8

1.1 Cotton 9

1.1.1 Types of cotton fibers 9

1.1.2 Characteristics of cotton 9

1.1.3 Properties of cotton 10

1.1.3.1 Physical properties of cotton 10

1.3.2 Chemical properties of cotton 11

1.2 Polyester 12

1.2.1 Types of polyester 12

1.2.2 Characteristics of polyester 12

1.2.3 Cotton polyester blend 13

1.3 Spandex 14

1.3.1 Spandex Fiber Characteristics 14

1.3.2 Cotton lycra blend sample 15

Chapter no 2

Greige department 16

2.1 Fabric receiving 17

2.1.1 Report receiving and storage 18

2.1.1.2 Inspection 18

2.1.1.3 Inspection of faults 19

2.1.1.4 Analysis of Faults 21

2.2 Issuance 23

2.3 Department mechanicals 24

2.4 Winding process 24

Chapter no 3

Pretreatment department 26

3.1 Singeing 27

3.1.1 Objectives of singeing 27

3.1.2 Methods of singeing 27

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3.1.2.1 Gas singeing mechanism 28

3.1.2.1.1 Parameters of gas singeing process 28

3.1.3 Perble Sando Iron works Japan 32

3.1.4 Osth-off Singeing Machine 35

3.2 Desizing 39

3.2.1 Oxidative desizing 39

3.2.1.1 Role of process axillaries 41

3.2.2 Enzymatic desizing 41

3.2.2.1 Role of process axillaries 41

3.3 Differentiate of process and chemicals 45

3.4 Scouring 46

3.4.1 Surfactants 47

3.4.1.1Classification of surfactants 48

3.4.2 Detergents 49

3.4.3 Emulsifying Agents 49

3.4.4 Sapphire Mills ltd. Scouring Process 49

3.4.4.1 Machine Lay out: Perble Sando Scouring 51

3.5 Bleaching 53

3.5.1 Sodium Chlorite Bleaching 53

3.5.2 Hydrogen peroxide Bleaching 56

3.6 Mercerization 60

3.6.1 Chain mercerization 61

3.6.2 Sapphire mills ltd Mercerization Machine 62

3.6.3 Mercerizing Fiber Blends 63

Chapter no 4

4 Dyeing 69

4.1 Types of dyeing 69

4.2 Reactive dyes 71

4.2.1 Chemical structure of Reactive dyes 71

4.2.2 Methods of dyeing of reactive dyes 72

4.3 Disperse dyes 74

4.3.1 Application of disperse dyes 74

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4.3.2 Properties of disperse dye 74

4.3.3 Auxiliaries 75

4.3.4 Disperse and Reactive dyes in one bath 76

4.3.5 Advantages of Disperse dyes 76

4.4 Vat dyes 78 4.4.1 Machines for continuous dyeing 79

4.5 Machine details of Sapphire Mills ltd. pad-thermo sol 85

Chapter no 5Research and Experimental work 87

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Summary of Project:

The following fibers were studied during our project:

Cotton Polyester and cotton blend Cotton and lycra blend

All experiments and observations were taken on the fabrics used these fibers.

The following processes are discussed

Singeing Desizing Scouring Bleaching Mercerization Dyeing

All fibers mentioned above are tested at different processes with varying the standard conditions and the results are discussed in this booklet.

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CHAPTER NO. 1

Introduction to fibers

Chapter no 1

Introduction to fibers

1.1 Cotton

It is a soft, fluffy staple fiber that grows in a boll around the seeds of the cotton plant. Cotton the purest form of cellulose found in nature is the seed hair plants of genus gossypium

1.1.1 Types of cotton fiber

The normal lot of cotton contains three types of fibers

Mature fiber

Which swell to rod like structure in sodium hydroxide solution with continuous lumens and no well defined convolutions?

Immature fibers

These are the fibers which have not been given time to develop there secondary wall, so some of the proteins remain in the fibers which give lot shade during dyeing.

Dead fibers

In dead fibers the after swell width is less than one fifth of the maximum ribbon width. They are usually found on mid way b/w two convolutions.

1.1.2 Characteristics of cotton

Cotton, as a natural cellulose fiber, has a lot of characteristics, such as;

Comfortable Soft hand

Good absorbency Color retention Good strength Drapes well

1.1.3 Properties of cotton

There are two types of properties that should be described here.

1.1.3.1 Physical properties of cotton

Fiber length

Typical lengths of Upland cottons might range from 0.79 to 1.36in.

 

Length uniformity

Fiber strength is measured in grams per denier. The breaking strength of cotton is about 3.0~4.9 g/denier, and the breaking elongation is about 8~10%.

Color

The color of cotton samples is determined from two parameters: degree of reflectance and yellowness.

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1.1.3.2 Chemical properties of cotton

Cotton swells in a high humidity environment, in water and in concentrated solutions of certain acids, salts and bases.

Cotton degradation is usually attributed to oxidation, hydrolysis or both. Oxidation of cellulose can lead to two types of so-called oxy-cellulose, depending on the environment, in which the oxidation takes place.

Dyeing of cotton fiber

Cotton is dyed with the reactive and vat dyes in our concern. The experiments with their samples are given in chapter 5.

1.2 Polyester

Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. In other words, it means the linking of several esters within the fibers. Reaction of alcohol with carboxylic acid results in the formation of esters.

1.2.1 Types of Polyester

The polyester fibers are generally available in two varieties

PET (polyethylene terephthalate) and PCDT (poly-1, 4-cyclohexylene-dimethylene terephthalate).

1.2.2 Characteristics of polyester Polyester fabrics and fibers are extremely strong. Polyester is very durable: resistant to most chemicals, stretching and shrinking,

wrinkle resistant, mildew and abrasion resistant.

Polyester is hydrophobic in nature and quick drying. It can be used for insulation by manufacturing hollow fibers.

Polyester retains its shape and hence is good for making outdoor clothing for harsh climates.

It is easily washed and dried.

1.2.3 Cotton Polyester Blend

Cotton polyester blend is a very useful blend in textile industry because it has high rating of desired properties. This blend is mostly used for wearing.

Detection of cotton polyester blend

Cotton polyester blend can be detected by using the reflection of the ultra violet light as polyester refractive index is higher than cotton.

1.3 Spandex

Spandex, Lycra or elastane is a synthetic fiber known for its exceptional elasticity. Spandex is a lightweight soft, strong and very stretchable. In fact, spandex fiber was developed as an alternative to rubber but has a better quality than it. The name Lycra has also come to be a synonymous of spandex. However, Lycra is the trademark brand but it has become so popular that all the varieties of spandex are popularly referred to as Lycra. It is used to make stretchable clothing such as sportswear. It is used to make stretchable clothing such as sportswear. It is made up of a long chain polymer called polyurethane, which is produced by reacting polyester with a diisocyanate (-NCO) group on both ends. The polymer is converted into a fiber using a dry spinning technique.

1.3.1 Spandex Fiber Characteristics

Can be stretched repeatedly and still recover to very near its original length and shape

Generally, can be stretched more than 500% without breaking Stronger, more durable and higher retractive force than rubber Lightweight, soft, smooth, supple In garments, provides a combination of comfort and fit, prevents bagging

and sagging Heat-settable — facilitates transforming puckered fabrics into flat fabrics,

or flat fabrics into permanent rounded shapes Dye able Resistant to deterioration by body oils, perspiration, lotions or detergents Abrasion resistant When fabrics containing spandex are sewn, the needle causes little or no

damage from “needle cutting” compared to the older types of elastic materials

Available in fiber diameters ranging from 10 denier to 2500 denier Available in clear and opaque luster

1.3.2 Cotton lycra blend sample

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CHAPTER NO. 2

Pretreatment department

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The fabric comes from the weaving unit in this department. In the gray department the fabric are coming in two forms namely roller form and bale form the packing list are attached with the fabric and with piece detailing. There are two type fabric coming in greige, own fabric and commercial fabric. The main purpose of grey department is inspection of the fabric.

The other purposes of grey fabric are:

1. Fabric receiving2. Report receiving and storage report3. Inspection4. Issuance

2.1 Fabric Receiving

First of all the fabric comes from the weaving mills through transportation. The weaving mill handover the all documents to finishing unit by means of transportation incharge. In these documents all specification of fabric are presented e.g.

1. Quality;2. Bale No; 3. Construction;4. Blend;5. Roll No;6. Selvedge;7. Weight etc.

2.1.1 Report receiving and storage

The collector reports the received fabric to the greige department incharge. The documentation is saved as for record. After that the fabric is forward to storage or for directly inspection.

2.1.1.2 Inspection

The fabric is inspected to find the ratio of errors occur during manufacturing of fabric. In the gray department we have to inspect 10 percent of fabric. These defects are classified into three types:

1. Avoidable and unavoidable

2. Major and minor

3. Mendable and unmendable

While most of the faults in the fabric are avoidable some are unavoidable such as certain floats/smashes. Faults such as weft crack is considered to be a minor if it is within 1-2 cm while the same faults is major when it is more than 2cm. Certain defects such as isolated snarls could be mended while the others such as big cracks are un-mendable.

2.1.1.3 Inspection of faults

The most common or general faults are mentioned below:

i. Contamination : Presence of the any other fibers along with the original fibers in the fabric is called contamination. Mainly polypropylene, hair, jute etc. are some common contaminations.

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ii. Cockled yarn : Fluff or any material pressed by machine in warp or end is called cockled yarn. It forms hard surface.

iii. Color variation : At some places color is found different then the actual one.

iv. Oily weft : When weft or pick yarn is oily then it is called oily weft.

v. Black end : When end or warp is black may be due to oil is called black end.

vi. Count variation : In this case warp or weft may be thick or thin then the count shown in the construction. In this case cloudy like appearance occurs.

vii. Courses pick: One thick pick or weft is called course pick.

Some mechanical faults are given below:

i. Short miss pick : If pick or weft is missing at any point than it is called short miss pick.

ii. Short double pick : In this case two yarns in pick are found for short distance.

iii. Short end : Any warp or end may be missing.

iv. Double end : In this case double yarn is found in warp direction rather than the single one.

v. Miss pick : A pick or weft yarn is missing.

vi. Double pick : Double weft yarn is inserted by loom in a single stroke.

vii. Starting mark : When loom starts after a short stoppage it produces a pattern on fabric in weft direction called starting mark.

viii. Wrapping marks : It is just like starting mark but here the surface become very hard on weft side,

ix. Oil stains : It is the spot of oil dropped on the fabric from any machine part.

x. Loose ends : Warp yarn or end comes out of fabric and not properly interlaced, it does not remain straight and goes in zigzag way.

xi. Sizing stains : It is like oily stain but more opaque then oily stain.

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Some important mending faults are mentioned below:

i. Hanging thread : Any thread hanging in the fabric is called hanging thread.

ii. Mending : If slub is taken out or kink is pulled out then a space appears in fabric and called mending fault.

There are some faults may occur in selvedges also, these are given below:

i. Curled selvedge : caused due to incorrect balance of cloth structure between body and selvedge.

ii. Cut/torn or burst selvage : it is due to selvedge sticking to emery roller or damages caused by temple roller.

iii. Loopy selvedge : when the selvedge or cut the race board felt at the reed and the weft is caught on this groove when the slay beats up.

iv. Rugged or ragged selvedge : when the variations in tension of the selvedge ends.

v. Slacked selvedge: caused due the incorrect balance of cloth structure between the body and the selvedge.

vi. Tight selvedge: caused due to incorrect balance of structure between body and selvedge, selvedge yarns woven at high tension.

vii. Uneven selvedge : when variation in weft tension, lack of control on number of selvedge ends uneven selvedge is produced.

2.1.1.4 Analysis Of Faults

The methods employed for analysis of fabric defects are

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1. First piece inspection

2. Grey inspection

3. Point rate system

1. First piece inspection

The first piece of the newly gated loom is taken to the grey folding departments and is inspected fir design verifications. The report is immediately sent to the weaving department and if there is any defect the necessary changes are made.

2. Grey inspection

Fabrics are tested in grey state after weaving. In the grey inspection the fabric faults are identified and mended if they are mendable.

3. Point rate system

It is an American system. Two most commonly used point rate systems are

4-point rate system

10-point rate system.

4-point system

Given by American standard ASTM, the test method describes a procedure to establish a numerical designation for grading of fabrics from a visual inspection. This system does not establish a quality level for a given product, but rather provides a means of defining defects according to their severity by assigning demerit point values.

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Length of defect Points

3 inches or less 1

3 - 6 inches 2

6 - 9 inches 3

9 inches 4

Points to be remembered while using 4-point system are:

1. No running yard shall be penalized more than 4 points for warp and weft faults.2. For Fabric width exceeding 64"-66", Maximum penalty points can be increased above 4 per linear yard in proportion to the width.3. Defects appearing within one inch of either edge shall be disregarded.4. Any hole other than a pin hole shall be considered a major defect and assigned 4 points for penalty.

2.2 Issuance:

According to production planning and control department the production planning card is send to greige department according to this card the fabric is unroll and send to pretreatment department.

2.3 Department mechanicals:

INSPECTION FRAMES

No of machines : 3

Company : AL-HADDID (PAKISTAN)

ROLLING & UN-ROLLING MACHINES

No o machines : 2

Company : HSING CHENG (TAIWAN)

2.4 Winding process:

In this process the fabric are wind on batch’s because they are suitable for further process. The winding is achieved through the winding machine because the fabric are in roll or bale form they are difficult to process therefore we are done winding and suitable for further process. And forward to pretreatment department.

Inspection frame Al-HADID

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CHAPTER NO. 3

Pretreatment Department

3.1 Singeing

This is usually the first stage in pre-treatment; consist of destroying by burning all the tufts, fibers and hairs protruding form the surface of the material (yarn and fabric). There by giving it smooth and cleaning face. Singeing is generally done o grey goods before any other treatment. The fabric is singed on one or both sides by passing either over plates or heated cylinder or by gas flame.

3.1.1 Objectives of singeing

Surface hair traps air in the fabric when it is immerged in water. This means that it takes longer time for water to enter the fabric, singeing therefore indirectly helps to increase the fabric wet ability.

To prominent the woven structure of the fabric. To create smooth surface for printing. To prevent firstly or cloudy after dyeing. To prevent or minimize the tending of landed fabrics composed of cellulose and

synthetic fiber (mainly polyester) the form pills after abrasion during usage.

3.1.2 Methods of singeing:

Usually three types of singeing can be carried out:

i. Plate Singeing Machine.ii. Rotary Singing Machine.

iii. Gas Singeing Machine.

In Sapphire only Gas singing process is done so it is discussed below

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3.1.2.1 Gas singeing machine:

Gas Singeing is intended for single and double face singeing of fabric with passes through the guide roller. Then in brushing zone which rotate in the sense opposite to fabric to be singed. The brushes are placed in a special chamber from which dust and fluff removed form the fabric, which are further exhausted by a fan.

Then the fabric passes over gas burner with ceramics nozzles where singing is covered out. Coming out of the gas singeing machine a box containing water. This bath may also contain desizing agent. In this way after singeing we can desize and batched the fabric.

In Sapphire mills ltd. Single action machine, singe only, is installed. Machine specifications are given below:

3.1.2.1.1 Parameters of gas singeing process

The parameters which are belong the singeing is following

1. Flame height2. Flame Intensity3. Flame Distance4. Flame angle

1. Flame height

The height is of flame is same to every fabric so its should be common and height is 6 inches

2. Flame Intensity

The are three position of flame intensity in machine which are differ from fibers the position are following

Position1 Position2 Position3

I. Position1

Position1 is not use in machine due to draw backs. These draw backs are:

In this position the flame is directly in contact with fabric and metal roller due to which fabric damages and the roller heats up.

It has fewer angles between flame and fabric and has no medium for flame to cross the fabric surface.

II. Position2

Position2 is used for polyesters blends with lycra and all type of cotton blends. In this position the flame is in angle with the roller about 45-60’ and reflect its surface which burns only cotton hairiness.

III. Position3

Position3 only use for cotton in this positions the flame crosses the fabric surface and then burn the hairiness.

Sapphire mills ltd’s OSTH-OFF machine position 3 is shown below:

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3. Flame Distance

The distance of flame and fabric is same for all type of fabrics the distance is 25 – 30mm

4. Flame angle

The angle is differ by type of fiber its should be minimum 20 and maximum 30

For cotton (Heavy Quality):

The 20° is used for pure cotton

For cotton (Fine Quality):

25° angle is used for the fine quality cotton.

For polyester + Lycra:

30° angle is used for polyester and lycra blend.

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Types of Machines

There are two types of singeing machines are installed in sapphire

Perble Sando Iron works Japan

Osth-Off 423260 Wuppertal Germany

3.1.3 Perble Sando Iron works Japan

It is a continuous type pretreatment machine. Singeing is also done on this machine. In this machine firstly the fabric is dried through steam rollers for maintaining fabric moisture. If fabric has more moisture in its surface then singeing objectives can’t be achieved and if the fabric is more dried then there are possibilities of burning of fabric. After the steam rollers, there are six brushing rollers. These rollers remove the protruding fibers which are loosely held on the fabric surface and which fibers, these rollers can’t remove because they have strong relation with fabric surface, only emboss those protruding fibers which are burnt in further processings singeing.In Sapphire Mills ltd. gas singeing is in process. Gas flames are used to singe the fabric. Details of singeing process are mentioned above. After singeing in Perble Sando, after singeing, the fabric is washed with simple water.

Perble Sando Singe machine

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Parameters

These are following parameters

Machine Speed 50-150m/min Chamber temp 40°-42°C Flame Pressure 23mbar Flame tube temp is controlled by water circulation Flame intensity 30-60Hz Flame ratio 80% Air – 20% Natural gas

Different internal parts of Perble Sando singe machine are shown below in figures:

Flames positions can easily be seen in this diagram.

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Brushing rollers

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3.1.4 Osth-off Singeing Machine

It is a semi continuous machine. It is an advanced machine in which singeing, desizing and bleaching process can be done. In this machine singeing is done by gas flame. Single and double sided singe can be done.

Here in OSTH-OFF machine, singeing is done in any of three positions, mentioned above. Selection of flame position and angle depends upon the fabric quality which has to be processed. Physical diagram of Sapphire Mills Ltd is shown below:

After singeing, the fabric can also be desized. Enzymatic desizing is done on this machine. For the application, the fabric is dipped in a bath containing enzymes at specific temperature. For the proper reaction and complete removal of sizing agent, the fabric is wound on a batch and is rotated for about 8-10 hours

Parameters

These are following parameters

Machine Speed 50-150m/min Chamber Temp 40°-42°C Flame Pressure 23mbar Flame tube temp is controlled by water circulation

Advancement of this machine is that it can process singeing, Desizing as well as cold Bleaching

Recipe no 1

Machine OSTHOFF

Quality 20//10 slub+10 card 114”*48”

Blend 100% Cotton

Process Singe + Desize

Speed/min 80 m/min

Flame 23 mbar

Position 3

PP-1 (bar/ton) 2 bar/ton

Temp (‘C) S-1 85

PP-2 (bar/ton) 1.2 bar/ton

Temp (‘C) S-2 85

pH S-2 5.5-6.5

Grey fabric(before process) singe + desize(after process)

Explanation:

Recipe for every quality or every different fabric is different. Recipe depends upon the weight per unit of fabric. Here for the given quality machine speed should be maintained at 80 m/min. if this optimized speed is varies from the given fabric, it can cause a lot of damages i.e. if speed is decreased from the limit, the fabric may burn and if the speed increases, it might result in irregular singeing. Now if selection of flame position is discussed, it is also depends upon the fabric quality as discussed earlier. Generally in case of 100% cotton position 3 is preferred. In OSTH-OFF singeing machine, enzymatic desizing is done. For this purpose, the desizing material is applied to the fabric and left for enzyme reaction for about eight hours in batch form. This batch with desizing material (enzymes) is rotated continually for eight hours as for better and uniform application. So this is important to note that how much enzymes are applied on which quality, heavy or light quality. So pad pressures are also very important to be maintained in the whole application process. For the given quality pad pressures are optimized at 2bar/ton and 1.2bar/ton.

Recipe no 2:

Machine OSTHOFFQuality 14*14 82*50

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Blend 65% polyester, 35% cottonProcess Dry singeSpeed/min 130 m/minFlame 23 m barPosition 3PP-1 (bar/ton) -PP-2 (bar/ton) -Temp (‘C) S-1 -Temp (‘C) S-2 -Remarks

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3.2Desizing

The process which removes the sizing material in the grey fabric is called the Desizing process. When fabric is woven before the warp end is coated with the material (starch) it give the strength in the end which bear the looms forces and reduction in the broken of threads during weaving process. Then this material should be removed if it not removed yet it’s present on the fabric and make problems in dyeing. The desizing process is depending upon the sizing material which used before the weaving knows the properties of sizing material we set the desizing agents and process. In sizing material there is always glucose and cellulose is used. There is three types of desizing is present in textile sector.

Acid Desizing Oxidative Desizing Enzymatic Desizing

3.2.1 Oxidative Desizing

It’s also the one of the good technique in textile sector to remove the sizing material. In this technique used the oxidative chemicals like sodiumpersulphate (Na2S2O8) sodium hypochlorite, sodiumhy pobromite. This chemical takes part of reaction solublizing group (ONa+). Which impact the sizing material and remove the sizing material by help of water. In oxidative desizing there is only heavy quality will be treated because it’s high oxidative agent and damage the light quality and remarks is pin hole in it. The reaction open the hydro glucose rings at 2,3 hydroxyls converting into carboxylic acid. Which is soluble in water and starch is removed from fabric. We done practice on the oxidative agents the agents which we are used is the sodiumpersulphate. The oxidative desizing mostly done on the perbale sando machine which is continuous machine and desizing chamber is placed after the singeing. After singeing the fabric is proceeding to saturators. There are four hot washes for the better application. The basic purpose of hot saturators is to increase the fabric temperature, as the desizer is more likely to react in high temperature conditions. Temperature for these hot wash is 90°-95°C. After hot washes the chemical is applied by means of a trough. In trough, sodium persulphate, Felosan NKB, acetic acid, Heptol B-95 or VL is used. These chemicals have their own application. After it there is 3 cold washers which removed the soluble material and the process is done

For 100% cotton 20*16/108*50 (70D) (98% - 2%) Cotton lycra.

Grey fabric(before process)

Chemicals g/l Temp/PH

Sodiumpersulphate 1 90’C/4.5-5.5

NKB 1

Acetic Acid 0.4

B-95 2

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3.2.1.1 ROLE OF PROCESS AUXILARIES

I. Acetic acid:

Acetic acid is a weak acid. pH is controlled by this acid during process. The chemical formula of acetic acid is the CH3COOH. The PH of acetic acid is the 5-6 which is very useful to the oxidative agents. The Titration is placed after each compellation of Liquor because its good to make precipitate in the water.

II. Felosan NKB:

It is a soaping agent. It’s manufacture by the CHT chemical company. It’s give the soaping properties during the process which remove the starch cleanly in the farbric. Synergetic mixture of modified fatty alcohol alkoxlyates. pH-value 7.0 – 8.0. ALKAPOL NKB has a good stability in usual concentrations to acids, alkalis, metal salts as well as oxidation agents, reduction agents and hardening agents of the water.ALKAPOL NKB is also compatible with non ionic, anionic and cationic products. The product is not sensitive to frost.

III. Heptol B-95/VL:

It is a cleaning agent. It is used to clean the scattering from the rollers, caused by the fabric passage form these rollers. If this chemical not use in the process the pasing of fabric is must be difficult on rollers.

III.2.2Enzymatic Desizing

Enzymes are the bacteria which are not being lived or dead but work in suitable condition and temperature. There are two types of enzymes

Hot Cold

Hot enzymes are those who works only in hot condition and temp like the 90-95’c thy only activate on this temperature.

Cold enzymes are those whose works only in 25-30’c and it activate and suitable for working in this conditions.

Enzymatic desizing is the process in which enzymes are used in it and the starch is removed by the help of this. This technique is very suitable in textile sector and mostly used in the industry. It’s very fast process and also not toxic to environment. In Enzymes the main unit which degrade the cellulose is the amalyse because the sizing agent is used is amaloyse. There is three sources to get the amalyse

Malt Pancreatic Bacterial

Bacterial are form the sources but it only works in condition it’s very useful for desizing process and mostly alpha amalyse is present in it.

Enzyme has property it eat the starch by giving its time and no toxic is produce in it. We done our practice on the enzymatic desizing there is JRL is used in it. Osthoff singe machine done the desizing process because it is batchwise process. In this machine there is two tanks is presnt which capacity are the 500 ml in each tank and after it there is making of batch and it give the time of 8hr that removed the all starch in it when it give time the batch should be revolve it because all the starch is removed in it. When we used the enzymatic desizing there should be carefull the following parameters which are desizing chemical is based on it. : after singeing the fabric is proceed to saturated portion. There are two saturators. In which the temperature is 40°-42° C. If Osth-Off machine is used of oxidative desizing, cold bleaching should be done with this process. Saturator capacity is 500 liters/saturator. Stock tank at normal condition is 1000 litters but max. capacity is 2000 litters. Machine speed is 50-150m/min. Dancer rollers are used for proper tensioning. There are two nipping points in Osth-Off machine. Fabric is dipped in each saturator for 8 times for better chemical application. Treated fabric is wound on batcher

PH TEMP Type of Enzyme

For 100% cotton 20*20/100*20

Chemicals g/l Temp/PH

JRL 2 100’C/ 4-5.5

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NKB 1

Acetic Acid/ Formic Acid

0.6

B-95 2

Desize fabric

After the time there is should be wash in hot water at temp of 90’c If there is presence of any sizng material which removed by the hot water Time should be 10min

3.2.2.1 Role of process auxiliaries

I. Formic Acid:

Its optional acid in the process but its uses is more than the acetic acid because it gives accurate PH value for enzyme. PH is very important factor in enzyme cases if PH is not

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stable the enzyme is also not activated properly. Due to the accuracy in PH the process its give to better result. The PH is 5 - 5.5. The chemical formula is the CHCOOH and Manufacture Company is the calariant.

II. Felosan NKB:

It is a soaping agent. It’s manufacture by the CHT chemical company. It’s give the soaping properties during the process which remove the starch cleanly in the fabric. Synergetic mixture of modified fatty alcohol alkoxlyates. pH-value 7.0 – 8.0. ALKAPOL NKB has a good stability in usual concentrations toacids, alkalis, metal salts as well as oxidation agents, reduction agents and hardening agents of the water.

ALKAPOL NKB is also compatible with non ionic, anionic and cationic products.The product is not sensitive to frost.

III. Heptol B-95/VL:

It is a cleaning agent. It is used to clean the scattering from the rollers, caused by the fabric passage form these rollers. If this chemical not use in the process the pasing of fabric is must be difficult on rollers.

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3.3 Differentiate of process and chemicals

Discussion

During work we have analysis the whole Desizing process. In which the oxidative desizing is better as compare to enzymatic methods of Desizing because it is faster method of desizing and also continuous process. If we run this process time consumption is less and give better desizing. In this process we run a heavy quality. In this process if we run a light quality it may be damage and may create pine holes this is an side effect of oxidative desizing. If we are using oxidative desizing than we should done chloride bleaching during process.

Process Enzymatic oxidativeChemicals JRL SPSAuxiliaries Felson NKB Felson NKBAcid Formic acid Acetic acidOther auxiliaries B - 95 B- 95Ph 5 – 5.5 5 – 6.5Remarks Semi continuous ContinuousProblems Ph maintenance ParticipatesDifference Take 8 hrs, batch

madeContinuous, other process done like scouring

Experience & opinion

Complete desizing

3.4 Scouring

Scouring is a process in which we remove the foreign material of any kind on the fabric surface and as well as from the interior structure of it.Natural fibers contain oils, fats, waxes, minerals, leafy matter and motes as impurities that interfere with dyeing and finishing. Synthetic fibers contain producer spin finishes, coning oils and/or knitting oils. Mill grease used to lubricate processing equipment mill dirt, temporary fabric markings and the like may contaminate fabrics as they are being produced. The process of removing these impurities is called Scouring. Even though these impurities are not soluble in water, they can be removed by Extraction, dissolving the impurities in organic solvents,

Scouring plant of Sapphire Mills ltd.

Two main processes of scouring to achieve its objectives:

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Emulsification:

Forming stable suspensions of the impurities in water and

Soaponification:

Converting contaminates into water soluble components.

3.4.1 Surfactants

The word Surfactant is coined from the expression "surface active agent".As the phrase implies, a surfactant molecule possesses surface activity, a property associated with the chemical structure of the molecule. The characteristic feature of a surfactant molecule is its two ends attached by a covalent bond. The two ends have diametrically opposed polarities. The non-polar end is leophilic (strongly attracted to organic molecules) while the strongly polar end is leophobic (having little attraction for organic molecules) yet strongly hydrophilic (water loving). Duality of polarity causes the molecule to align itself with respect to the polar nature of the surfaces it contacts.

Physical Chemistry of Surfactant Solutions

When soap (heptol B-95) molecules are added to pure water one molecule at a time, the first few molecules align at the air/water interface and the hydrocarbon tails orient toward air. The driving force for this alignment is the non-polar tail seeking to associate them with the most non-polar interface it can find, in this case air. As additional molecules are added, they too will align at the water/air interface until all of the surface area is completely packed. As more molecules are added, they are forced into the bulk of the water, floating about as individual a molecule until a saturation level is reached. At this point, called the Critical Micelle Concentration, soap molecules agglomerate into water soluble clumps (Micelles), where the lyophobic tails are associated with themselves and the hydrophilic heads are surrounded by water molecules. The first beaker represents close packing of surfactant molecules at the surface. The second beaker represents the condition before micelle formation. The third beaker shows the formation of micelles.

3.4.1.1 Classification of surfactantsSurfactants are classified according to use, to ionic charge and to chemical Structure. By Use Wetting Agents: The ability of a liquid to spread on a smooth solid surface is dependent on the polar nature of the solid and the surface tension of the liquid. A non-polar solid surface such as paraffin wax or Teflon will cause a drop of pure water to bead-up and not spread. Water containing surfactants on the other hand will easily spread on paraffin surfaces and have lower contact angles on Teflon.

Types of surfactantBy Ionic Charge

Anionic: Those surfactant that develop a negative charge on the water solubilizing end.

Cationic: Those surfactant which develop a positive charge on the water solublizing end.

Non-Ionic: Those surfactant that develop no ionic charge on the water solubilizing end.

Amphoteric: Those surfactant that have both a positive and negative charged group on the molecule

3.4.2 Detergents

These are surfactants that help remove soils from solid surfaces. Over and above reducing water's surface tension, detergents must adsorb onto the soils surface to aid in spontaneous release. Detergents must also keep the soil suspended to prevent redeposit ion.

3.4.3 Emulsifying Agents

These are surfactants that convert water-insoluble oils into stable, aqueous suspensions. The lyophobic part of the surfactant molecule is absorbed by the oil droplet and the

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lyophobic head is oriented outward, surrounding the droplet with a hydrophilic sheath. Ionic surfactants add another dimension to the stability of emulsions; they set up a charge-charge repulsion field which adds to keeping the droplets separated.

3.4.4 Sapphire Mills ltd. Scouring Process

In sapphire there is caustic soda is used for scouring, with scouring sometimes the oxidative desizing agent is present in it. If there is enzymatic desizing the scouring is done individually and alone caustic soda, Heptol B-95, NKB is present in the tough. During scouring, the titration is of the solution is done at the intervals of approx 10min. There is concept that more titration more it is advantageous and the process comes reliable. The concept of titration is that it controls the precipitate formation in the tough and water keeps good for the process. For titration there is the KMNO4, dil H2SO4 used. Both are strong acid and base. In sapphire the scouring is done on the perble sando machine where is parameters is checked and the machine description is given below. In sapphire the scouring is done by means of a J-Box. For this purpose, first of all the fabric is passed to saturators. In these washes the temperature is about 95°C as the fabric is preparing for chemical treatment. Now chemical is applied on the fabric by means of a trough.In j-box there is time needed for the further operation but this time varies by changing in fabric quality even by changing the fiber type but the time is about 23-28 min it means that the fabric is placed in the j-box and treated with steam at temperature, approx 100’C and fabric is under treatment of steam. This steam energizes the ions of scouring chemicals and chemical action is ready to take control.

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J-Box and saturators of sapphire

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3.4.4.1 Machine Lay out: Perble Sando Scouring

Scouring machine parts;Cold wash;Scouring chemical bath;Steamer (J-box);Washers;4 hot washers

Cold washer scouring chemical bath

Steamer hot washer

Recipe no1:

Quality 16*162/88*52

Blend 100% cottonMachine & process Perble, Singe+Desize (osth-off)

Machine ConditionsTitration NaOH

Recipe Saturator Chamber saturator ChamberCaustic (NaOH) 80 g/l 150 kg Chamber time 30 min 84-86

g/lSodium persulphate - 35 kg Boil box temp 99’CFelosan NKB 2 g/l 20 kg Toppart temp 98’CHeptol B-95 1 g/l 10 kg Pad pressure 7-1Level 4 (ton)

Recipe no 2:

Quality 20*12(70D)/104*48Blend 98%cotton 2%Lycra

Machine&Process Perble, Singe+Desize (osth-off) Machine Conditions

Titration NaOHRecipe Saturator Chamber saturator ChamberCaustic (NaOH) 80 g/l 150 kg Chamber

time30 min

73-74 g/l

Na2S4O8 - 35 kg Boil box temp

99’C

Felosan NKB 2 g/l 20 kg Top part temp

98’C

Heptol B-95 1 g/l 10 kg Pad pressure

7-1

Level 4 (ton)

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3.5 Bleaching

Scouring generally removes all impurities from the cotton except coloring matters therefore bleaching is done after scouring. This is the process in which natural and other coloring matters are discolored either with reducing or oxidizing agents. Almost invariably oxidizing agents give a more permanent white.If cloth is to be finished white or is to be given surface ornamentation, all natural colours must be removed by bleaching. This is also necessary if discoloration or stains have occurred during the previous manufacturing process. Bleaching can be done in yarn stage as well as in the constructed fabric. When cloth has been bleached for finishing it is called bleached goods. All bleaching processes reduce the strength of the fibre. If durability is more important then appearance; the consumer should select greige goods rather than bleached material. With continued laundering, greige goods will gradually whiten.There are some commonly used bleaching agents.

Reducing bleaching agents

SO2, NaHSO3, Na2S2O4

Oxidizing bleaching agents

KMnO4 Cl2 and ClO2 Na2O2 NaOCl and NaClO2 (Sapphire)

BaO2 Ca(OCl)2 H2O2 (Sapphire)

3.5.1 Sodium Chlorite Bleaching

Sodium chlorite was actually introduced for bleaching of synthetic fibres but now it is found that it can be used for bleaching cotton goods.Bleaching activity of sodium chlorite is highly dependent on pH, Generation of different degradation products and rate of decomposition may vary with the change in pH.Bleaching occurs most rapidly below pH 1-2, rapidly at pH 2-3, and the rate decreases as the pH increases.

General Recipe:

NaC1O2 10 g/l

Sodium chlorite, bleaching agentHOOCH 2g/lFormic aid, to maintain pH at 2.2-3.5CH3 OH 1g/lMethyl alcohol, buffer to maintain pH

Chamber time 22minBoil Box Temp. 95-99Top Part Temp. 95-98Pad Pressure 7--1Saturator Temp. 40

Saturator

At the back of the Perble tanks are given for the chemical preparation. Recipe chemicals are fed to these tanks and pipe lines connect these tanks to the metering pumps, filters and to the saturator.Fabric to be bleached is impregnated with the sodium chlorite solution and squeezed by a padder to remove the excess liquor and to ensure the even pickup. After impregnation fabric goes to the chlorite chamber

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Chamber

Chlorite chamber is slightly different from scouring chamber. It is completely closed chamber having no drainage for chemicals, no recycling of liquor due to the highly toxic nature of chlorine dioxide, capacity of this chamber less then scouring chamber. Chlorite chamber is coated from inside with titanium to prevent any damage by the corrosive nature of chlorine compounds, Excess of chlorine gas is produced in this chamber which is collected and shifted away from the working area through ducts, where it is processed. Chlorite chamber has no plate for pilling the fabric but it has wings which control the movement of fabric. After completion of required dwell time fabric goes to washing baths for washing.Specifications are as given Fabric Capacity 2800 meter Dwell time 20-25 min Temperature 97-100 °C Under liquor level 3.5-4.0 ton

De-chlorination Chamber

Treatment of liberated chlorine gas is necessary to minimize any health hazards. De-chlorination chamber is used for this treatment. Treatment is done by showering of hydrogen peroxide and sodium hydroxide to the chlorine gas. Reaction is given as under,

For chlorine dioxide

ClO2 + H2 O2 ———> HCl + H2ONaOH + HCl ———> NaCl + H2O

For chlorine

Cl2 + H2 O2 + 2 NaOH ———> NaCl + H2O+ O2

Washing Baths

After chlorite chamber fabric enters into washing baths. In first washing bath an anti chlor treatment is given to the fabric with HT enzyme, which removes chlorine from the fabric. After anti chlor treatment fabric goes to next washers where it is washed with hot water at temperature of 80-90 ºC

3.5.2 Bleaching with H2O2

In case of heavy quality fabric or fabric having lycra blend, bleaching is carried out with hydrogen peroxide. In most organic and inorganic compounds which contain oxygen (e.g. water, metal oxides, alcohols, carbonates) the oxygen atom is bounded to other type of atoms. The oxygen in these atoms can not easily be split off. On the other hand oxygen in all the peroxides and per salts is bonded such that two oxygen atoms are bonded to each other. This linkage in these compounds can be much easily broken librating one atom as active oxygen. Hydrogen peroxide is used as bleaching agent on natural cellulose (cotton, linen, jute) as well as the protein fibers (wool, silk) etc. it is also effective on blended fibers as pc.

Bleaching Action:

It is generally agreed that the first stage is an ionization to form per hydroxyl ion (HOO-)H2O2 ——> HOO- + H+

The formation of per hydroxyl ions is favored by alkaline conditions and so most H2O2

bleaching is carried out under this condition.A number of reactions can also occur, particularly in presence of metallic catalysts, to convert it into water and molecular oxygen.2H2O2 ——> 2H2O + O2

+

This break down is more rapid in highly alkaline solution. The molecular oxygen escapes from the bleach solution reducing the bleaching effect and intermediates in its formation are very active and can cause fiber damage. Selection of alkali to be used in peroxide bleaching is dependent on the fibers or blend being bleached. Sodium hydroxide (caustic soda) and sodium carbonate (soda ash) will be used generally on cellulose fibers.

Bleaching tests:There are three types of tests done after bleachingTegwa test: this test is used for observing the starch percentage.Absorbency test: the test used to check the absorbency of the fabric after bleaching.

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pH test: the test used to check the neutralization of the fabric or ph of the fabric.

General Recipe:

H2 O2 18 – 38 g/lBleaching agentFelosan 1.5 – 2 g/lWetting agent Heptol B-95 1 – 3 g/lSequestering agentNaOH 3 – 10 g/lActivatorStabilizer SIFA 2 – 8 g/l

Machine parameters:

Chamber Time 20-25 minBoil Box Temp. 95-99Top Part Temp 95-98Pad Pressure 7 m-barSaturator Temp 40-45

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Chlorite Bleach fabric

Saturator:

After passing from cold washer the fabric enters into hydrogen peroxide saturator, which contains the following chemicals.

1. H2 O2 (bleaching agent)2. Felosan NKB (wetting agent) 3. Heptol B-95 (sequestering agent) to remove iron particles4. NaOH (caustic)5. Stabilizer SIFA

Chamber:From saturator, saturated fabric enters into peroxide bleaching chamber and here bleaching of fabric occurs. This chamber is similar to the chlorite chamber capacity wise and process wise but the chemicals are different. Here we use hydrogen peroxide as bleaching agent.

Washing Baths:

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After coming-out from peroxide bleaching chamber, we pass the fabric from four hot washers and then finally pass to last chamber, which has neutralizing agent.Temp of 1st,2nd & 3rd Washers are 98 C and 4th is 60 C.Pad Pressure is 1.6 Ton.

Drying:3 columns of drying cylinders are used.12 cylinders per column.Temp or pressure of total 36 cylinders is 0.3 MPa each.

Discussion and Research:

The research which we observe during bleaching process is that losses the strength during the process at least 70%. In the process there is two chemicals which done the bleaching process is the peroxide bleaching and the chlorite bleaching the main thing which difference when it the chlorite bleaching is the more toxic and not durably in bleaching but it use because of the less time and whole bleaching process. The peroxide bleaching is time consuming and slow process. Chlorite bleaching needs the oxidative desizing before which the main disadvantage. The best bleaching is the cold bleaching which is not toxic and no limitation need but there is less production problem. Our opinion is that used the peroxide bleaching which suitable for every machine and mill. Therefore we should used peroxide bleaching this process very suitable for proper bleaching because it is very important stage of processing. Without Proper and suitable bleaching we will unable to achieved required property in fabric.

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3.6 Mercerization.

The process, in which we improve absorbency of the fabric, and dimensional stability control its shrinkage. This is done by the help of strong alkali (NAOH). In Sapphire the NaOH is main chemical for mercerization.

This process gives the strength, dimensional stability and smoothness to fabric. In process NAOH, salt, caustic, soap is used.Mercerizing require cotton to be treated with concentrated solutions of sodium hydroxide (caustic soda). Mercerization requires higher concentrations of caustic soda (19 to 26 % solutions). The procedure is effective in completing the removal of motes that may have escaped the scouring and bleaching steps. Caustic soda solution swells cotton fibers breaking hydrogen bonds and weak van der Waal forces between cellulose chains. The expanded, freed chains rearrange and re-orient and when the caustic soda is removed, the chains form new bonds in the reorganized state. When done tensionless, the cotton fiber swells, the cross section becomes thicker and the length is shortened. Because of fiber thickening, the fabric becomes denser, stronger and more elastic. Held under tension, the coiled shape of the fiber is straightened and the characteristic lumen almost disappears. The fibers become permanently round and rod like in cross section and the fiber surface is smoother. Decrease in surface area reduces light scattering, adding to fiber luster. Tension increases alignment of cellulose chains which results in more uniform reflection of light. The strength of the fiber is increased about 35 %. The fiber also becomes more absorbent.The cellulose crystal unit cell changes from cellulose I to cellulose II and the amorphous area become more open, therefore more accessible to water, dyes and chemicals. Mercerized cotton will absorb more dye than un-mercerized cotton and in addition, yields an increase in color value a given quantity of dye.The amount of fiber shrinkage is a measure of the effectiveness of caustic soda's ability to swell cotton.

Types of mercerization

Chain Chain less

3.6.1 Chain Mercerizing

Chain mercerizing is done on a range equipped with tenter chains for tension control. The range consists of a pad mangle followed by a set of timing cans and then a clip tenter frame. Fresh water cascades onto the fabric to remove the caustic soda as it is held tensioned in the tenter frame, . The length of the frame must match the range speed and assure that the caustic level is reduced below 3% before tensions are released. The tenter frame is followed by a series of open-width wash boxes which further reduces the caustic level. Acetic acid is in one of the last boxes to complete the neutralization of caustic.

Procedure

1. Apply 22 to 25 % (48 - 54" Tw) caustic at the pad mangle at 100 wet pickup.2. Pass fabric over timing cans. The number of cans must correspond to the range speed and provide at least one minute dwell time. 3. Clip fabric onto tenter chains and stretch filling-wise while maintaining warp tension. 4. Run fabric under cascade washers to remove caustic. Keep under tension until caustic level is less than 3% otherwise fabric will shrink in filling direction. This width loss is impossible to recover later. 5. Release tension and continue washing in open-width wash boxes, to further reduce the caustic. 6. Neutralize with acetic acid in the next to last wash box and rinse with fresh water in the last.

3.6.2 Sapphire mills ltd Mercerization Machine

In sapphire mercerization set up was installed by SANDO IRON WORKS WAKAYAMA, Nichimen Corporation. Two machine lines are installed one line was cotton and polyester blends and other is for pure cotton the difference between both machines is number of trough. One has two troughs and the other have three. The two troughs are 22 be calibration is used and the three troughs using 28 Be caustic soda.

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Mercerization Trough

Mechanically, in mercerization, the fabric is passed through a stanter. The purpose of this stanter is to maintain the width of the fabric. Before the process the width of the chain is adjusted as required. Before chain, the fabric is treated with caustic soda. Caustic soda is applied in a trough. There are three chemical troughs in both mercerizing machines. Use of three chemical troughs is because of better application. All troughs are one dip one nip. In all troughs, 28 Be NaOH is applied. After trough the fabric is given some time about 11-15 sec. There are 14 timing rollers for 1st trough. 11 timing rollers for 2nd trough and given 7-8 sec. after 3rd trough, the fabric is transferred to chain. At chain, NaOH is showered on the fabric when it is being passing through the chain. This showering is because the fabric has lost some of its amount during passing through chain. So showering recovers the leaked amount of caustic soda.

Caustic Concentration Units

Caustic concentrations, expressed as percentages, are ratios calculated as weight caustic/weight solution. However the specific gravity or density of the solution (weight/volume) is directly related to the concentration. Calibrated hydrometers are used to determine specific gravity. The calibration scales most often used on caustic solutions are Twaddle (“Tw) and Baume’ (“Be’). The relationships between concentration and hydrometer readings are:

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The relationship between the Baume’ scale and concentration is not linear, the values get closer at higher concentrations. The reader is referred to various handbooks and manuals that have conversion tables.

3.6.3 Mercerizing Fiber Blends

Color yield, ease of dyeing and uniformity of dyed fabric will offset cost of Mercerizing. This holds true even for yarn blends with low levels of cotton. The temptation to Mercerize must temper with thoughts about how caustic affects the blending fiber. The following section discusses these issues.

Polyester/Cotton

These can be handled under the same conditions as 100 % cotton. Even though polyester fibers are sensitive to caustic, the temperature and time the fibers are in contact with mercerizing strength caustic are insufficient to cause fiber damage. One problem with polyester/cotton blends it that they may not be as absorbent as 100 % cotton fabrics coming to the caustic saturator. This is because they have not been given the same thorough scouring and bleaching as 100 % cotton. In this case, special penetrating agents are needed to help the caustic solution wet out the fabric.

Quality 16*16/2 88*52

Blend 100% CottonMachine ConditionsChain width 65

Required full width 59 – 60

Width After 61 full

Speed 60

NaOH (Be)o 28

showers 5

Name Pad P. Temp. pH Fabric resultsW. mangle PP 7 normal Tegwa 7-81st saturator 6 pH 5-6

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2nd saturator 8 Absorbency okFeed mangle 1.5 whiteness 75-76After chain 1.5Washer no 1 1/0.2 80 11-12Washer no 2 1/0.2 90 11-12Washer no 3 1/0.2 95 10-11Washer no 4 1/0.2 60 10Washer no 5 1/0.2 normal 2Washer no 6 1/0.2 normal 2Washer no 7 1/0.2 60 2Washer no 8 1/0.2 80 3-4Washer no 9 1/0.2 90 5-6Washer no10 1/0.2 90 6-7

Washerno11/ B4Drye PP

7 normal 4

11 Washer of mercerization

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Quality 16*12/120*60Blend 100% CottonMachine ConditionsChain width 63Required full width 58Width after 59.5Speed 55NaOH (Beo) 28showers 5Name Pad P. Temp. pH Fabric resultsW. mangle PP 7 normal Tegwa 7-81st saturator 6 pH 5-62nd saturator 8 Absorbency okFeed mangle 1.5 whiteness 67-68After chain 1.5Washer no 1 1/0.2 80 11-12Washer no 2 1/0.2 90 11-12Washer no 3 1/0.2 95 10-11Washer no 4 1/0.2 60 10Washer no 5 1/0.2 normal 2Washer no 6 1/0.2 normal 2Washer no 7 1/0.2 60 2Washer no 8 1/0.2 80 3-4Washer no 9 1/0.2 90 5-6Washer no 10 1/0.2 90 6-7Washer no 11/ B4 Dryer PP

7 normal 4

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Mercerized fabric 2. Mercerized fabric

Discussion:

In the mercerizing process the chemical (NaOH) we bring the chemical from the industry of 48 boma. Before application of caustic we should make it a dilute. For this purpose we were adding water on it. After this, the concentration will be 28 boma for the application. In sapphire mills ltd. we vary the quantity of caustic during this experiment. The change will occur in the absorbency of the fabric; if we used the excess amount of caustic than the structure will be deteriorated and the dimensional stability will be disturbed rather than any improvement and less amount of caustic, it will unable to increasing absorption and dimensional stability. 3

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CHAPTER NO. 4

Dyeing Department

4 Dyeing

The process of imparting color to any colorless or colored material is called dyeing. Dyeing of textile materials (fibers) is called textile dyeing. Textile dyeing is a very ancient process….The color materials used in dyeing are called dyes. Dyes are forced to make bonds or strong interactions with fibers. The interaction of dye and dyed material is important for better results. This means that dyeing is not only the process of imparting the dye into the fiber but it also include the good and strong chemical attachments between both, dye and fiber. This chemical bonding is responsible for good wash fastness properties, light properties etc.Dyeing is done in aqueous medium. As dyes are in different forms like powder or liquid, so it is better to use aqueous medium. Different liquid ratios are used according to dyeing method. The solution includes the fibers (to be dyed), the dye and the auxiliaries.The purpose of these auxiliaries is to improve efficiency of dyeing in other words they help to make strong and lasting connections between dye and fibers. These auxiliaries for dyeing vary according to the dyeing material and condition in which the dyeing is being done. These auxiliaries include the retardants, levelers, wetting agents, detergents etc.

4.1 Types of dyeing

There are different types of dyeing processes according to the condition these conditions include the type of fiber, type of dyeing material and temperature conditions etc. there are three main types of dyeing process:Continuous dyeing;Semi continuous dyeing;Batch-wise dyeing.

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Types of dyes

There are different types of textile dyes. These are different in chemical formula, chemical nature, physical and chemical properties, and their behavior with different fibers.Some dyes are cationic, some anionic and some are neutral and etc. Dyes are classified into different classes according to their nature. Some are given below:Reactive dyes;Disperse dyes;Vat dyes;Acid dyes;Mordant dyes;Sulpher dyes;Cationic dyes, etc.We process only reactive, disperse and vat dye due to Sapphire mills limitations, so only these dyes are discussed here.

4.2 Reactive dyes

Among the different classes of dyes for the cellulosic fibres the reactive dyes are the only ones that attach themselves to the fibres by covalent bonds and get their name for the same reason. Reactive dyes have certain groups in their molecules that are capable of forming of covalent linkages between carbon atom of the dye ion and oxygen, nitrogen or sulpher atom of a hydroxyl or amino group respectively of the fibrous substrates. At this stage it is relevant to consider the basic mechanisms of the dye fibre attachments that can be of three types:

Physical adsorption Mechanical retention and Chemical reaction

4.2.1 Chemical structure of Reactive dyes

After the success of procion dyes in 1953, all the major dyestuff manufacturers begin investigating to find new reactive groups. In 1958 after going through their wool dyes ranges, introduced Remazol dyes that formed the covalent bond by “nucleophilic addition” reaction as indicated below:

(-HCl)D-SO2CH2-CH2Cl = [D-SO2CH=CH2] + HO-Cell = D-SO2CH2-CH2OCell These developments made the colour chemists think seriously, perhaps for the first time, about the chemical structures of fibres especially of cellulosic fibres and their role in dyeing mechanisms. In subsequent years all the major dye manufacturers many new reactive groups. It is known that about 250 reactive groups have been patent but only 20-30 have actually been marketed for both cellulosic and protein fibres by cold as well as hot dyeing process.The four distinct structural features of mono-functional reactive dye are chromogen, the reactive system, the bridging link and one or more solubilising groups. The structure can be represented as:

W-D-Q-RG-XWhere D is the chromogen, W is the water-solubilising groups, Q the bridging link, RG the reactive group and X the leaving group.Some reactive groups are shown below:

Reactive group Trade name manufacturer

D-SO2CH2-CH2-NR2 Remazol(Hoechst)

Dyestar

D-NHCOCH2CH2OSO3H +D-NHCOCH = CH2Cl

Primazine(Base)

Dyestar

The reactive dyes are the brightest dyes available for the cellulosic fibres and have a full range of shades with very good wash and fairly high fastness properties. These dyes offer a great flexibility in application methods with a wide choice of effeuipment and process sequences and so have become very popular. As a class, the reactive dyes are stable to peroxide bleaching and so are used for dyeing cotton and viscose yarns to be employed as effect threads. Strong reducing agents and chlorine however destroy the chromogen.

4.2.2 Methods of dyeing of reactive dyes

In the absence of alkalis, the reactive dyes behave like levelling class of direct dyes but being of relatively smaller molecular size, are exhausted with higher concentrations of electrolytes. Even then exhaustion of the dye is low and varies between 50-75% in most classes. Reactive dyes can be applied by various methods but choice of dyeing process depends on factors such as availability of equipment, depth of shade, length of fabric and how much production is required.

Here in Sapphire mills limited, dyeing process is limited to full continuous method due to the limitations of equipment as well as it is the production requirement.

Reactive dye Recipe

Reactive dyes 60G/l

Reduction inhibitor 10g/l

Anti migrating agent 10-15 g/l

Wetting agent 2 g/l

Pick up 65%

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4.3 Disperse Dye

Disperse dye is originally developed for the dyeing of cellulose acetate. They are substantially water insoluble. The dyes are finely ground in the presence of a dispersing agent then sold as a paste or spray dried and sold as a powder. They can also be used to dye nylon, triacetate, polyester and acrylic fibers. In some cases a dyeing temperature of 130 deg C is required and a pressurized dye bath is used. The very fine particle size gives a large surface area that aids dissolution to allow uptake.

Disperse dyes have low solubility in water, but they can interact with the polyester chains by forming dispersed particles. The general structure of disperse dyes is small, planar and non-ionic, with attached polar functional groups like -NO2 and -CN. The shape makes it easier for the dye to slide between the tightly-packed polymer chains, and the polar groups improve the water solubility, improve the dipolar bonding between dye and polymer and affect the color of the dye. The dye is generally applied under pressure, at temperatures of about 130oC. At this temperature, thermal agitation causes the polymer's structure to become looser and less crystalline, opening gaps for the dye molecules to enter. The interactions between dye and polymer are thought to be Van-der-Waals and dipole forces.

4.3.1 Application of disperse dyes

Dyeing Polyester with Disperse Dyes

Polyester requires the use of disperse dyes. Other types of dyes leave the color of polyester almost entirely unchanged. While novices happily charge into dyeing with acid dyes (for wool or nylon) and fiber reactive dyes (for cotton and rayon), often with excellent results, the immersion dyeing of polyester is a different story.

4.3.2 Properties of disperse dye:

Fastness to light is generally quite good, while fastness to washing is highly dependent on the fiber. In particular, in polyamides and acrylics they are used mostly for pastel shades because in dark shades they have limited build-up properties and poor wash fastness.

4.3.3 Dyeing with disperse dyes may require the use of the following chemicals

and auxiliaries:

· Dispersing agents: although all disperse dyes already have a high content of dispersing agents, they are further added to the dyeing liquor and in the final washing step· Carriers: for some fibers, dyeing with disperse dyes at temperatures below 100 °C requires the use of carriers. This is the case with polyester, which needs the assistance of carriers to enable an even penetration of disperse dyes below boiling temperature. Because of environmental problems associated with the use of these substances, polyester is preferably dyed under pressure at temperature >100 °C without carriers. However, carrier dyeing is still important for polyester-wool blends, as wool must not be submitted to wet treatment at temperatures significantly above 100 °C · Thickeners: polyacrylates or alginates are usually added to the dye liquor in padding processes. Their function is to prevent migration of the dye liquor on the surface during drying· Reducing agents (mainly sodium hydrosulphite): they are added in solution with alkali in the final washing step.Disperse dyes are widely used not only for dyeing, but also for printing synthetic fibers.

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Light fastness:

The photofading behaviors of anthraquinone disperse dyes on polylactide fabrics were investigated. The fabrics which had been dyed with 13 commercial dyes were exposed to a carbon arc light source. The polylactide fabrics dyed with Disperse Red 127 or Violet 26, which has phenoxy substituents, showed the light fastness higher than 4 grades.

4.3.4 Disperse and Reactive dyes in one bath:

If we want to dye polyester/cotton blend in one bath(i.e. both the reactive and disperse in the same bath instead of two bath) then the parameters we need to consider besides what must be the properties of both the dyes to withstand in one bath giving good results and fastnesses from pastal shades to darker shades.

The temperature and chemical requirements for the dye reaction of fiber reactive dyes, versus the dye deposition of disperse dye, are so different that the idea of combining both in one step seems bizarre. Disperse dye is applied at a boil, using a chemical to reduce the temperature needed for dye transfer, while reactive dyes, unlike direct dyes, are generally applied at considerably lower temperatures, and may actually degrade quickly when boiled.

4.3.5 Advantages of Disperse dyes

The disperse dyes used for the dyeing hydrophobic advantageous from the dyes used for cotton and wool fibers in the following respects:

Essentially low molecular weight azo, anthraquinone and diphenylamine derivates.

Carry no charge groups but contain polar sites like –OH, -NH2, -CH2-CH2-OH etc. Crystalline solids with low molecular weight that melt under pressure at 200-

250’C and sublime without decomposition. Low substantivity that increases with rise in temperature and by addition of a

dispersing agent. The solubility ranges from 0.2 to 100 mg/l at 80’C but completely dissolve at 130’C.

Relatively high saturation value ranging from 30-200 mg/gm of hydrophobic fibres.

Particle size of marketed dye is low (about one micron) so as to accelerate the rate of dyeing.

Disperses dyes x g/l

Dispersing agent 5 g/l

Anti migrating agent (cetanol BL)

5-15 g/l

Wetting agent(FFAM) 2 g/l

Pick up 65%

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4.4 Vat dyes

Vat dyes form a very important class of dyes for the cellulosic fibers because the dyeing produced with these have the highest overall fastness properties. All of these dyes have good fastness against wet treatments and crocking and most have light fastness in the region of 6-7. the vat dyes can also with stand oxizing agents like hydrogen peroxide, sodium chlorite and hypo chlorites, and extensively used for dyeing yarn that is to be woven along with the grey yarn. The present day vatting chemicals are sodium hydroxide and a strong reducing agents (one with high reduction potential) sodium dithionite (Na2S2O4) commonly termed in industry as sodium hydrosulphite or simply hydros. Sodium dithionite reduces the keto group of the dyes into the enol form and sodium hydroxide forms sodium salt of the enol to make the dyes water soluble. Caustic soda also neutralizes the acidic decomposition products of the reducing agent dithionite that are produced during vatting and dyeing. Quantity of the reducing chemicals depends upon the no of the keto groups present in the dyeing molecules to the extent of exposure of the dye bath to air. The reduction process may be represented as shown below:

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4.4.1 Machines for continuous dyeingThe basic equipment required for the continuous dyeing of fabric of cotton and its blends with man-made fibers are dye padder, infra-red, pre-dryer, cylinder or hot air dryer, chemical/development padder, steamer or thermo-fixation, heater, washing range and cylinder dryer. These machines are in the process of continuous improvement but the basic function of the equipment remains essentially the same. A brief description of the important features of these machines is discussed below:

Padder:

The padder is the padding mangles are meant to apply dye liquor in an even manner to the entire width and the length to a batch of fabric. The padding operation consists of two parts:

Immersion of the fabric in dye liquor in a trough. Passing the fabric between two rollers to force the dye liquor into the fabric and

also to squeeze the excess liquor back to the trough.Padder is the most sensitive component of the continuous dyeing system as any fault develop at the padding stage will not be corrected later. Padders usually have two rollers although the three roller types with two dip troughs where also marketed but these are used mainly for applying finishes to the heavy weight fabrics. Diagram given belowThe padder roll has a steel mandrel that is covered with hard rubber, toped by 15 mm of soft rubber that has the hardness of 60-70’ shore. Both the rollers should have exactly the same hardness other wise there will be a color difference in the face and back side of the fabric. The material of the rubber should be chemically resistant to dye liquors and auxiliary products. The bottom roller is coupled with a variable speed motor so that the fabric may is run at the linear speed ranging fro 30-90 m/min. the usual liquor pickup in a modern padder for different fiber is as under.Cotton: 60-70% p/c: (50:50) 45-50%

Padding trough:

The padding trough that was once considered to be just a container for the dye liquor without realizing its importance in obtaining a uniform shade and dye economy, has now, like padders, undergone vast modifications in recent years. The trough is placed below and in front of the padder and consist of the U shaped box with one or more free running guide rollers of about 10cm diameter each, as shown in figure below:

. An expander roller is fitted before the nip of the roles to eliminate any creases that may develop during passage of fabric through the trough. The dye liquor is fed in through a perforated pipe running across the entire light of the tank with perforations pointing towards the wall of the trough and away from the fabric so as to avoid spraying of the dye liquor on fabric

Ideally a trough should contain the minimum quantity of the dye liquor consistent with adequate pickup so as it reduce the wastage of the unused dye at the end of the process and more importantly to have a high liquor replacement value. In continuous dyeing, dye should have no or minimum possible affinity with the fibers so that the dye liquor squeezed out of the fabric during padding and returning to the trough should have the same concentration as the freshly fed dye solution. In case the dye has a slightly affinity, the trough should have as low of volume as possible so that the liquor is replaced rapidly and concentration of the dye solution in the trough remain constant and there is negligible or small tailing effect. To reduce the volume of the dye liquor, or displacer is fitted above the single roller trough. In oil roller troughs the displacer becomes unnecessary while time of contact of fabric with dye liquor increases. The troughs are double weld so that hat or cold water could be circulated through the jacket to maintain, usually automatically, the dye liquor at constant and optimum temperature. To ensure constancy of the fabric immersion time through out its funning in the trough, level of the dye liquor is kept constant by automatic controls.

Drying the dye padded fabric:

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To get even and uniform results specially for medium and deep shades, the dye padded fabric is required to be dried before the dye is made to diffuse into the fibers by steam or thermofixation. A no of drying machines such as cylinders, hot flue, infra red, stanter, suction dryers etc. are available but their choice depends upon important consideration of uniformity of drying, capital cost and thermal efficiency as well as some special requirements. We have studied infra red dryers in Sapphire mills limited.

Infra red dryers:

These are the heaters which working the electrically or by gaseous. These heaters are mounted on the bricks and there are installed on top side of the thermosle machine. The main objective of IR dryers is pre drying of fabric before the main dryers which not affect the structure of fabric. The drying action take place from the both side as the bricks is present the face and back. The number of bricks present on the one side is the 52 bricks. The infra red rays need the 700 c on the fabric surface for this purpose temp of bricks should be at least 1400c. The fabric passed between the heaters 80m/min. The width of the chamber is the 2.2ft. This chamber is completely isolated that no temp can be leaked out from this chamber.

IR chamber thermosol

Continuous steamer:

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In continuous roller steamer is used for the diffusion of the reactive, vat and sulpher dyes into cotton fibers in an atmosphere of heat and moisture that is created by saturated steam injected into the steamer. The fabric is moved in open width around rollers in top and bottom horizontal banks in a heat insulated steel chamber like that of a hot flue dryer. The top rollers are driven by chains or preferably by a series of motors. Capacity of the steamers varies between 30-60m and the time of steaming ranges between 20-60sec depending on class of dye used and depth of its shade. The steam coil heats ceiling of the machine to avoid condensation of steam and subsequent dripping of water on the dye padded cloth. Temperature of the steamer is maintained 102-104’c for getting the optimum results. The fabric enters the steamer through a narrow and heated slot so as to prevent entry of air into it and to eliminate condensation of steam on the fabric. It is essential to have a minimum of air in the steamer so that there Is no premature oxidation of sulpher and wet dyes and also to avoid lowering of evaporation temperature of the steam. The elimination is air is done before entry the fabric by blowing steam and forcing air out of steamer through an outlet in the roof. In some steamer air is rewove through a duct near the floor of the machine and is claimed give better extraction because air is heavier than steam.

When leaving the steamer, the fabric passes through a cold water seal so that steam doesn’t escape from the exit. The water in the seal should be kept cool by continuous running of fresh cool water in it especially when steaming the wet dyed fabrics as other vise the seal would become a reducing dye bath. After steaming the fabric is fed into a continuous washing range for removal of the unfixed dye and chemicals.In Kusters, steam is generated by boiling water at atmospheric pressure at 100’c inside the steamer itself.

Thermofixation of dyes:

In the thermofixation (also incorrectly called thermosol) process of dyeing the synthetic fibers, the disperse dyes diffuse into the polyester fibers on bringing the dye padded fabrics to a temperature of 200-220’c for a contact time of 60-30 sec. the machines commonly used for such dye fixation are mainly hot flue, stanter and suction drums. The hot flue machines are basically similar to the hot air dryers except that temperature of the hot air is maintained at 200-220’c with heated oil. The stanter, which was originally used as a finishing machine to stretch cloth to a constant and specified width, has now been extensively modified and technically upgraded for the thermofixation and heat setting purposes.

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4.5 Machine details of Sapphire Mills ltd. pad-thermosol:

Pad-thermosol consists of following parts that dye and guide the fabric during dyeing:

Batcher Guide rollers Scray Cooling drum Trough Squeezing rollers Padder VTG rollers IR-dryers Drying chambers Radiator Heat exchanger Curing chamber Piller

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CHAPTER NO. 5

Research and Experimental Work

In sapphire finishing lab there is following machine:

Auto color Sampling pad Vertical heater Pad chemical steam Curing machine Precise balance

Auto color:

This machine is used for the auto coloration process with the mixture of many colors. In this machine the bottles fix in machine there is liquid form dyes are placed and the suckers part of machine is take it into by the help of computer programming and the mixture of color is going to the main bath which the mixture is present in it. The traveling of color is done by the capillary tubes. The computer is operate the whole machine and though. Corel draw software is placed in the computer by help of this the combination of color is possible. The advantage of this machine is that the precise recipe is generated and labors work is save the fine quality is for better sampling an its produce the light shade.

Sampling pad:

There is simple pad is used which the padding of sample is done below it the tank is present where is recipe is being used places and its working on following parameters.

Pad Pressure (1 – 10mbar) Speed (10 – 100 m/min)

Vertical heaters

These are substitude are inferrad heaters and the sample is dry in it. There is one contnous chain which clip is present and the holders which hold the fabric is placed in

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the clip. The fabric is rotate is the whole machine in the 1 min. 12 heater is presnt in it 98.c is the temp of every heater. Its only for used the pre heating chamber.

Curing machineThe curing machine is done the cure process there is 210 – 230 *C. in this machine we achieved both functions dry and fixation of fabric, the temperature is vary according to fiber to fiber. If we change dye than we should change the temperature also. Time is an important factor but we change timing quality to quality, normally required time is 40 second to half minute, but it is not constant it is vary from quality to quality.

Pad chemical steamIn the pad chemical steam firstly we apply chemical on fabric after that we washed the fabric. Finally we should neutral the fabric otherwise we could not achieve required property. When we washed the fabric in this time the extra thing are removed from fabric and last we neutral it. Initially chemical is used, after this we wash the fabric and last we neutral the fabric. In this process we did three functions at times padding, applying chemicals and steaming. During steaming fixation is achieved.

Precise balanceIt is balance which is used to measure the amount of dyes, colors and chemicals during the measuring we should be careful because it is very cautious issue, if we have a little bit mistakes than we are unable to achieved required result and shad. Therefore it is essential for us to proper measuring the chemical and dyes otherwise we could not achieved required result. That why we used the precise balance it is sufficient to accurate measuring. His least count is 1mmg it is used to accurate measure the chemicals and dyes.General recipes for sapphire dyeing lab

Reactive dyes recipe

Reactive dyes XG/lReduction inhibitor 2g/l

Anti migrating agent(FFAM) 10-15 g/lWetting agent(FFAM) 2 g/l

Pick up 65%

Condition

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Pad Dry Chemical Pad Steam 50g/l Naoh 50g/l Glauber salt 50g/l soda ash

Vat Dyes recipe

Vat dyes XG/lDispersing agent 1-2 g/l

Anti migrating agent 10-15 g/lWetting agent 2 g/l

Pick up 65%

Condition Pad Dry Cure Sodium hydrosulphite(50g/l) Soda ash(50g/l)

Dispress dyes recipe

Dispress dyes XG/lDispersing agent 1-2 g/l

Anti migrating agent(cetanol BL) 5-15 g/lWetting agent(FFAM) 2 g/l

Pick up 65%

Condition Pad Dry Cure Curing Temp is 200’C – 210’C 1 ½ min

Personal LAB recipes

Reactive dyes 60G/lReduction inhibitor 10g/lAnti migrating agent 10-15 g/l

Wetting agent 2 g/l

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urea nilPick up 65%

Condition Pad Dry cure 50g/l Naoh 50g/l soda ash

Sample

Reactive dyes 60G/lReduction inhibitor 10g/lAnti migrating agent 10-15 g/l

Wetting agent 2 g/lurea 60g/l

Pick up 80%

Sample

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ResultIf we use urea than dye is totally fix because urea has ability to increase penetration of dye and give good effect and hand fell. In sample 1 we keep urea is nil than the dye is not completely fix therefore they give dark effect and give less washing fastness and hand fell. In sample 2 we use 60g/l urea resultant they give light effect and good hand fell. Because urea has ability to fixation and soft handling. Finally these experiments prove that presence of urea give better effect for dyeing.

Changing the wetting agent

Reactive dyes 60G/lReduction inhibitor 10g/lAnti migrating agent 10-15 g/lWetting agent(HS) 5 g/l

urea 60g/lPick up 65%

Sample

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Reactive dyes 60G/lReduction inhibitor 10g/lAnti migrating agent 10-15 g/lWetting agent(HS) nil

urea 60g/lPick up 65%

Sample

ResultThe above lab experiment is shows that if we used nil amount of wetting agent than resultant the fabric has less ability of water absorbency because the wetting agent has ability to increase the absorbency of water. And the wetting agent is capable to change the hydrophobic nature of fabric into hydrophilic therefore they it good for dyeing if the fabric absorbency is good than we achieved good result and it essential for dyeing. If we increase the amount of wetting agent darkness and softness is increase. In the absence of wetting agent not give better effect and the hardness effect is produce. In sample 1 we use the amount of wetting agent is 5g/l therefore there effect is better than the sample 2 because in sample 2 we used nil amount of wetting agent.

Changing the parameters

Reactive dyes 60G/lReduction inhibitor 10g/l

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Anti migrating agent 10-15 g/lWetting agent(HS) 5g/l

urea 60g/lPick up 65%

Pad pressure 1.2mbar

Sample

Reactive dyes 60G/lReduction inhibitor 10g/lAnti migrating agent 10-15 g/lWetting agent(HS) 5g/l

urea 60g/lPick up 65%

Pad pressure 1.6mbar

Sample

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ResultThis is mechanical experiment in this method if we increase pressure on the fabric than whiteness of fabric will be decrease and if we apply less pressure quantity on fabric resultant they give good whiteness effect on fabric. Normally pressure is used to improve the fabric whiteness effect. In above two samples we have changed the pressure therefore the effect of fabric is varying from each other. In sample 1 we keep pressure 1.2mbar therefore the result on fabric is not batter and sample 2 we applied 1.6mbar pressure therefore there whiteness effect is better than sample 1.

Vet dyes

Vat Dyes recipe

Vat dyes 60G/lDispersing agent 1-2 g/l

Anti migrating agent 2 g/lWetting agent 2 g/l

Pick up 65%

Condition Pad Dry Cure Sodium hydrosulphite(50g/l) Soda ash(50g/l)

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Vat dyes 60G/lDispersing agent 1-2 g/l

Anti migrating agent 5 g/lWetting agent 2 g/l

Pick up 65%

.Vat dyes XG/l

Dispersing agent 1-2 g/lAnti migrating agent 10 g/l

Wetting agent 2 g/lPick up 65%

ResultIn this process we have to change the anti migrating agent. Because anti migrating is used to prevent the dye migrating, it is also used to dye leveling therefore it is very essential for dyeing recipe. If we used the great amount of anti migrating agent than our shad effect will be good. In sample 1 we keep the amount of anti migrating is 2g/l therefore his shad effect is not good and sample 2 we used the quantity of anti migrating

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is 5g/l therefore his shad effect is better than as compare to sample 1, in last sample we apply the anti migrating amount is 10g/l therefore his shad effect is better than both sample 1 and 2.finally we conclude that if we increase the amount anti migrating agent than resultant it give better shad effect on fabric.

Vat dyes 60G/lDispersing agent 1-2 g/lAnti migrating agent 10 g/lWetting agent 2 g/lPick up 65%

Vat dyes 60G/lDispersing agent 1-2 g/l

Anti migrating agent 10 g/lWetting agent 5 g/l

Pick up 45%

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Vat dyes 60G/lDispersing agent 1-2 g/l

Anti migrating agent 10 g/lWetting agent Nil

Pick up 30%

ResultVats dyes are mostly used in cotton and polyester fiber. Basically this is play role as a paste, they are penetrate in fabric, in vats dyes if we used wetting agent they give better shad effect on fabric. Because it has ability to make the hydrophobic region of fiber changed into hydrophilic. If the fabrics nature is changed into hydrophilic than, it will be suitable for dye penetration and resultant the shad effect will be good. In above lab experiment tell us if we used wetting agent in vats dyes they give good shad effect on fabric. In sample 1 we used the 5g/l amount of wetting agent therefore they give excellent fabric shad effect after that if we used nil amount of wetting agent that whey their shad effect is not good.

Disperses dyes recipe

Disperses dyes 60G/l

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Dispersing agent 1-g/lAnti migrating agent(cetanol BL) 5-15 g/l

Wetting agent(FFAM) 2 g/lPick up 65%

Condition Pad Dry Cure Curing Temp is 200’C – 210’C 1 ½ min

Disperses dyes XG/lDispersing agent 3-g/lAnti migrating agent(cetanol BL) 5-15 g/lWetting agent(FFAM) 2 g/lPick up 65%

Disperses dyes XG/lDispersing agent 5-g/lAnti migrating agent(cetanol BL) 5-15 g/lWetting agent(FFAM) 2 g/lPick up 65%

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ResultsIn the above dyeing recipe we have to change the dispersing agent. If we changed dispersing agent than resultant the shad effect will be occur. Because it has ability to make hydrophobic fiber into hydrophilic, actually the dispersing dye is naturally insoluble therefore we should make this into soluble, that, s why we are using the dispersing agent they are making the dispersing dye in soluble form. If we use less amount of dispersing agent than the dye will be less soluble that’s why we are using require amount of dispersing agent. In above dyeing recipe we have changed the amount of dispersing agent therefore give different shad effects. If we used 3g/l of dispersing agent than they give not better shad effect. And we apply the 5g/l amount of dispersing agent resultant they give excellent shad effect.

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CONCLUSION

The conclusion of our project is to study and the optimization of the pretreatment and dyeing recipes and the role of their axillaries. We deeply study the processes of

pretreatment and dyeing, their mechanicals and chemical parameters. The auxiliaries are playing very important role in textile wet processing. All the advancements and

developments in textile are focused in this department. It is based on the chemical research work. If any industry wants to improve their production and quality they should be intended their recipes, lab work and efficiency. These parameters are also important

for the better, advanced fabric characteristics and compete the international market.From our experiments and practical work we conclude that more optimization is

required in pretreatment and dyeing processes and development in it. We should bring more advancement and development in dyeing and pretreatment to achieve best quality

according to fabric value because these are the back born of textile sector. During the project work we perform the chemical experiments and explore the textile sector

through our ideas and our struggle. Through our experiments we conclude that the recipes used in Sapphire Mills Ltd. are much optimized but these can be improved

through varying the different chemical concentrations. In our lab experiment we have done different experiments, and finally we conclude that if we vary the amount of

chemicals, we have achieve different results like if we change the amount of urea during dyeing the shade will vary. If we use less amount of urea than or shade effect will be light and if we use more amount of urea the shade will be dark. We are very satisfied from our

experimental research work and involvement of our supervisor and staff of Sapphire Mills Ltd.

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