FINAL YEAR PROJECT REPORT INDUS INSTITUTE OF HIGHER EDUCATION KARACHI THE STUDY OF DENIM WASHING A PROJECT SUBMITTED TO THE FACULITY OF TEXTILE SCIENCES IN PARTIAL FULFILMENT OF REQUIRMENTS FOR DEGREE OF BACHELOR OF TEXTILE SCIENCE (B S TEXTILE) SUPERVISED BY: ENGR ABDUL SALAM FACULTY MEMBER. Email: [email protected]SUBMITTED BY: SYED ASIM NAJAM ID: 1002 MARCH, 2009 Indus Institute Of Higher Education 1
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FINAL YEAR PROJECT REPORT
INDUS INSTITUTE OF HIGHER EDUCATION
KARACHI
THE STUDY OF DENIM WASHING
A PROJECT SUBMITTED TO THE FACULITY OF TEXTILE SCIENCES
IN PARTIAL FULFILMENT OF REQUIRMENTS FOR DEGREE OF
ACKNOWLEDGMENTSAll thanks are due to Almighty “ALLAH” the most beneficial and merciful who enable
us to complete this project.
The completion of this project is perceived as the fruitful result of and incredible effort,
devotion and hard work. It can be stated without any hesitation that this thesis is the
outcome of the joint effort of all concerned by successfully negotiating the various
tedious problems and hurdles.
We are particularly thankful of Sir Adbul Salam our project advisor for the guidance and
valuable cooperation render by him at any stage regarding this project. He fully indulged
himself to facilitate our job whenever approached him to seek guidance regarding this
study.
Special thanks are reserved for the Head of Textile Science Department Sir Hasib-u-
Salam for encouraging and motivating throughout the successful completion of this
project. We are very thankful to each and every person of Ragby Industries specially Sir
Ejaz Shah, who make ourselves very comfortable during our whole internship program,
who led us to complete this project work.
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Faculty of Textile ScienceINDUS INSTITUTE OF HIGHER EDUCATION
Karachi.
Certificate
I am pleased to certify that the following students have satisfactorily carried out a thesis work, under my supervision on the topic of “Denim Washing”
I further certify that his thesis is worthy of presentation to the Faculty of Textile Sciences, INDUS INSTITUTE OF HIGHER EDUCATION Karachi for the degree of Bachelor of Science in Textile.
1. Syed Asim Najam2.
HOD Textile Science: ---------------------------
External Examiner: ----------------------------
Supervisor: ------------------------------
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TABLE OF CONTENT
Content Page No.
Chapter 1
1.1 Introduction
1.2 Back ground
1.3 History of denim
1.3Literature Review
1.4 Area of study
1.5 Expected Results
Chapter 2 Warping
2.1 Introduction
2.1.1 Direct warping
2.1.2 Indirecy warping or sectional warping
2.1.3 Ball warping
2.1.4 Draw warping
2.2 Components of amchine
2.3 Procedure of warping
Chapter # 3 Dyeing
3.1 Introduction
3.2 Classification of dyes
3.2.1 Direct dyes
3.2.2 Reactive Dyes
3.2.3 Disperse Dyes
3.2.4Sulphur Dyes
3.2.5 Vat dyes
3.3 Denim dyeing
3.3.1 Rope dyeing
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3.3.2 Slasher dyeing
3.4 Difference between rope dyeing and slasher dyeing
3.5 Cooking tanks and dsoing system
3.6 After-washing process and drying
3.7 Sizing
3.8 Drying zone
3.9 Accumulator
3.10Leasing zone
3.11 Expansion comb
3.12 Beaming
3.13 Transportation of beams
Chapter 4 Weaving
4.1 Introduction
4.2 Basic weave design
4.3 Shedding system
4.3.1 Crank shedding
4.3.2 Cam shedding
4.3.3 Dobby shedding
4.3.4 Jacquard shedding
4.4 Classification of weaving machine
4.4.1 Shuttle weaving
4.4.2 Shuttle less weaving
Chapter 5 Faults in production of denim
5.1 Faults of warping
5.1.1 Faults in machine
5.1.2 Faults in raw material
5.1.3 Faults in product
5.2 Faults of dyeing
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5.2.1 Faults in machine
5.2.2 Faults in raw material
5.3 Sizing Faults
5.4 Weaving Faults
Chapter # 6: Denim washing
6.1 Introduction
6.2 How does washing create unique look
6.3 Processes involve in Denim washing
6.3.1 Dry process
6.3.2 Wet process
6.4 Types of denim washes
6.4.1 Chemical wash
6.4.2 Mechanical wash
6.6 Spraying
6.7 Whiskering
6.8 Softening process
6.9 Machine use for denim
6.10 New development toward economical and ecological denim processing
6.11 Value edition
Chapter 7
7.1 Conclusion
7.2 Reference
1.1 INTRODUCTION
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Denim and jeans - where do the names come from? The word jeans come from a kind of
material that was made in Europe. The material, called jean, was named after sailors from
genoa in Italy, because they wore clothes made from it. The word 'denim' probably
came from the name of a French material, serge de nimes: serge (a kind of material) from
nimes (a town in France),
1.2 BACKGROUND
• We have interest in denim washing.
• Denim has fewer difficulties in process as compare to other dyeing process.
• Few industries work on this topic so that’s why we decide to do the topic and we
will try to optimize the process and try to invent new washes or finishes in denim.
• Denim is a universal fabric, one that covers all age groups, races and social
divides that’s why we think it will have high demand in the future and this is also
the point of our attraction for this topic.
1.3 HISTROY OF DENIM:
In fashion history, jeans and denim history continues to baffle. No one truly knows the
perfect answer to where jeans began. As so often happens fashions often emerge
together in various parts of the world and are the result of the sudden availability of a
new fabric, cloth, dye or technique. But we do know that the phrase denim jeans are
thought to derive from several sources. No one is totally certain where the words come
from. A majority of source books suggest that denim derives from the English
translation of the South of France French phrase 'serge de Nîmes'. Denim fashion
history is thus associated with Serge de Nimes.
When talking about denim the name Levi´ s is one of the first to be mentioned. Levi´ s
which stands for Levi Strauss is normally called the forefather of jeans. When tracing
back the history of these trousers to its origins it is true that Levi Strauss played an
important role concerning their development and distribution but he had also other
inventive business partners.
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Levi Strauss found out that the gold diggers´ hard work in the mines made their clothes
get worn out very quickly and he produced stout working trousers out of the sail cloth he
had taken with him which he called „half overalls“. When he continued producing these
trousers he used cheap cotton fabrics coming from Genova. The name of the town of
Genova was modified into „jeans” in the American slang. At the end of the sixties of the
19th century he replaced the brown sail cloth by an indigo-dyed, wear resistant cotton
fabric coming from France. The name of this fabric was „Serge de Nimes“. Serge is the
French. Expression for a combined twill and Nimes is the French town where the fabric
comes from. The fabric´s name Serge de Nimes was quickly turned into „Denim“ in
American colloquial language. By applying this indigo-dyed combined twill the first
jeans out of Denim was almost born or better sewn. The application of metal rivets for
jeans is due to the Polish emigrant Jacob W. Davis, also called AJacob Youphes.
Although the working trousers out of Denim were stout they had a tendency to get worn
out where the pockets were. Jacob Youphes mended the trousers with a needle and
thread. One day a customer inspired him to repair the torn off pockets with the help of
rivets. Under the management of Levi Strauss the jeans were now produced in series.
Since the trousers were so stout not only the gold diggers liked them but which is not
surprising in America? The cowboys appreciated them very much, too. When the trousers
were applied as working trousers for cowboys, however they got worn out at the crotch
tip. This was no problem for Levi Strauss and Co. since they reinforced the trousers again
with metal rivets at the crossing point of the four seams at the crotch tip.
About 1947 denim made a break-away from work clothing image, chiefly in the area of
sportswear and rainwear and an occasional appearance in high fashion collections as a
"different-looking" evening dress. In 1970 American youth adopted denim as their
favorite fabric. Part of a "back to nature" movement that emphasized ecology and the
natural denim being a fabric created from a natural fiber was a primary factor. Since 1960
the jeans business has undergone an explosive transformation, from a source of tough,
cheap clothing for cowboys, blue-collar workers and penniless youth into a fashion
conscious market for a widening mass of people of almost all ages.
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1.4 LITERATURE REVIEW
The studies related to the denim manufacturing and processing is available to understand
the process sequence and achieving various washing effects of denim.
Processes for producing yarns dyed with indigo have been in use for thousands of years.
The original batch methods for dyeing yarn skeins have been replaced for the most part
with continuous dye ranges that can produce thousands of pounds of dyed yarns each
hour. Different experiment have been done before on denim washing, denim dyeing they
are done internationally as well as locally in our country in which few are discussed
below.
• In past, stone (pebbles) are use for washing which is known as stone wash but
now a days stone (pebbles) are replaced by rubber balls because stone damaged
the fabric during the washing process.
• Another experiment was done internationally and primary object of the invention
is to provide a method of treating denim fabric in plain fabric form or in garment
form to economically produce stonewashed denim fabric of various different
shades colors without multiple steps, expensive equipment, or large inventories of
fabrics and dyes. Another object of the invention is to economically provide
stonewashed denim fabric of different shades and colors.
• In earlier work many denim washes has been created in which some denim
washed names are given below:
1 ACID WASH
2 ENZYME WASH
3 BLEACH WASH
4 STONE WASH
• Companies that “finish” jeans by washing them or distressing them for a worn-in
look. Most major jeans manufacturers use several different laundries that
specialize in different finishes. The main techniques used include simple washing,
stonewashing, which uses an abrasive-bristled Tonello machine, sandblasting,
laser burning, or applying enzymes to simulate “cat’s whisker”-wear line, and
sandpapering by hand.
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• Our seniour students also worked on denim washing and they also tried to
developing the new techniques in denim washing but unfortunately they were not
success in developing new techniques.
1.5 AREAS OF STUDY:
In this project we will study denim washing along with its weaving and its dyeing process
and we will try to optimize the current methods but we will focus deeply on denim
washing and its finishing.
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WARPING
The first process in the manufacturing of denim is warping.
2.1 INTRODUCTION
Warping is the process of transferring multiple yarns from individual yarn packages onto
a single package assembly. Normally, yarns are collected in a sheet form where the yarns
lie parallel to each other and in the same plane onto a beam, which is a cylindrical barrel
with side flanges. This is known as beam warping. For ball warp denim, the yarns are
brought together and condensed into a rope before being wound onto a relatively short
cylindrical barrel (sometimes called the shell or log) that has no end flanges.. In both
cases, the supply yarn packages are placed on spindles, which are located in a framework
called a creel.
Ball Warping :
In ball warping (Figure 5), 250 to 400 yarn ends are pulled from the creel. The yarns then
pass through a comb-like device (sometimes called a hack or reed), which keeps each
warp yarn separate and parallel to its neighboring ends. At intervals of every 1000 or
2000 yards (or meters), a lease string is placed across the sheet of warp yarns to aid yarn
separation for the re- beaming operation, which will occur later. The yarns then go
through a funnel-shaped device called a trumpet or condenser, which collapses and
condenses the sheet of yarn into rope form. This device is located at the base of the
warper head and traverses back and forth, guiding the newly formed rope of yarn onto a
log. The rope must be wound at a constant tension to keep the yarns from tangling.
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Beam Warping
Beam warping maintains the yarns in an open sheet form and winds the yarns parallel to
each other onto a slightly wider flanged beam. These yarns will not go through the rope
indigo dye range, but are left “natural” and will end up either slasher dyed or in an un-
dyed fabric, which can later be piece dyed, garment dyed, or left natural. Another option
would be to beam dye the yarns using a dye other than indigo.
2.2 COMPONENTS OF MACHINE
• Creel
• Rods
• Chain System
• Control Devices
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• Sensors
• Head stock
• Expansion Comb
• Dust and fly accumulation unit
Showering assembly
2.3 PROCEDURE OF WARPING:
The creel stand has maximum capacity of five cones per stand.
The yarn from the cones is unwounded and passes from rod by cross wound, holed by a
catcher guided to the tensioning zone when cone rotates anticlockwise. There are three
types of tension in warping i.e. catcher tension, rod tension, and sacker tension. Magnetic
tensioner is used for yarn tension.
Then the yarn comes to the winding zone or headstock. Combs straighten the yarns
towards pressure drum, which supports beam, and yarns in an alignment so that each and
every yarn end can wound separately. Static charges due to friction of yarns on metal
surface cause static charges, which are removed through an anti static device. Then the
yarn is wounded on beam in this way for a required length if beam is changed after one
filling of beam then knotting of yarns is made. Similarly if cones are finished on one
frame side then trolley system of cone changing is used in this way chains rotates the
whole frame of empty side and new filled side of frame is forwarded again knotting is
done between the new cones yarn and already winded yarn. Extra yarn is then removed
through cutting. Sensors sense any type of yarn breakage and in case of yarn breakage
knotting is done.
DYEING
3.1 INTRODUCTION
Dyeing is a process in which we impart colour into the fabric. All commercial textile
dyeing processes take place by the application of a solution or a dispersion of the dyes to
the textile material followed by some type of fixation process. The dye solution or
dispersion is almost always in an aqueous medium. A major objective of the fixation step
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is normally to ensure that the coloured textile exhibits satisfactory fastness to subsequent
treatment in aqueous wash liquors. Dyeing is mainly depends on the type of fabric,
structure of fabric and the properties of dyes.
3.2 CLASSIFICATION OF DYES
For our convenience we make classes of dyes, due to these classes the application of dyes
is much easier. The classifications of dyes are as follows:
• Direct Dyes
• Reactive Dyes
• Sulphur Dyes
• Vat Dyes
3.2.1 DIRECT DYES
Direct dyes have been used to dye cellulose for over 100 years. Because of the simplicity
of application and great choice of products available, direct dyes are a popular dye class.
Direct dyes ranges from moderate to poor in wash fastness. Light fastness varies from
poor to excellent depending on the particular dye. Direct dyes depend on secondary
forces such as hydrogen bonds and vander waals forces to bond with cellulose fibres.
Since secondary forces are relatively weak. Therefore, direct dye molecules have
relatively high molecular weights, typically 400 to 1200. The great majority of direct
dyes are azo structures.
3.2.2 REACTIVE DYES
Reactive dyes contain groups that react with the hydroxyl groups in cellulose. The
reaction between a reactive dye and the fibre produces a covalent bond. By their nature
reactive dyes also react with water. Dye which reacts with the fibre is said to be “fixed”
to the fibre. Dye which reacts with water is said to be “hydrolyzed”.
Fixation Reaction
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Cell – CH2 – OH + DYE – X Cell – CH2 – O – DYE + HX
Cellulose reactive dye dyed fibre acid
X=reactive group
Hydrolysis reaction
H – O – H + DYE – X DYE – OH + HX
Dye molecules which react with the fibre and become fixed have excellent fastness to
washing because of the high strength of the covalent bond. Dye molecules which are
hydrolyzed may be weakly attached to the fibre and if not washed out at the end of the
dye cycle have very poor wash fastness.
3.2.4 SULPHUR DYES
Sulphur dyes are widely used on cotton mainly because they are economical to use. They
have good to excellent wash fastness and good light fastness in dark shades. Light
fastness of pale shades is poor. Sulphur dyes are usually dull in shade since the molecular
structures are complex. As a class, the sulphur dyes are not resistant to chlorine
containing bleaches.
Chemical nature of sulphur dyes
3.2.5 VAT DYES
Vat dyes are mainly on cellulosic fibres, but some can be applied to protein fibres. They
usually have outstanding colourfastness properties. Vat dyes are more expensive and
difficult to apply than other classes for cellulose such as directs sulphurs, and reactive.
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Indigo is a special case in the vat dye class. Indigo is attractive for its pleasing blue
colour and for the unique fading characteristics of garment dyed with it.
Vat dyes are characterized by the presence of a keto group. Vat dyes in keto form are
water insoluble pigments.
CHEMICAL CONSTITUTION OF VAT DYES
Reactions of Indigo Dye
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THE SUBSTANTIVITY AND DYEING CHARACTERISTICS OF
VAT DYES FOR CELLULOSIC FIBRES.
BASIC STEPS IN THE DYEING PROCESS
The dyeing of cellulosic materials with vat dyes follows a four-step sequence:
1. Preparation of the vat containing the leuco forms of the dyes;
2. Dyeing of the material, in which the fibers absorb the water-soluble leuco
compound;
3. Oxidation of the absorbed leuco compound back to the parent pigment inside the
fibers
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4. Soaping of the dyed material to remove pigment loosely adhering to the fiber
surfaces and to develop the true shade and fastness properties.
3.3 DENIM DYEING:
The classical jeans were produced out of indigo-dyed Denim fabric. The special character
of this fabric only the warp thread is dyed makes it necessary to carry out dyeing in yarn
form. The yarns applied for Denim were exclusively produced on ring spinning machines
in former times. The development of OE (open end) yarns by applying smaller rotors
with a spinning speed of up to 200 m/min - has led to the application of OE rotor yarns
both for warp and weft. The yarns applied for weaving must be of high quality: a high
fiber for strength, regularity as well as a small part of short-stapled cotton fibers belong to
the basic features of the denim yarn. For regular jeans qualities the warp yarns are spun in
a fineness of 50 to 90 tex, for the weft yarn the fineness ranges are mainly 75 to 120 tex.
If Denim is made out of Tencel or Modal especially for jeans shirts the finenesses are up
to 25 tex.
Indigo, sulphur and indanthrene are mainly used in the dyeing process. Two methods are
applicable for continuous dyeing with indanthrene dyes: rapid dyeing and vat dyeing.
While processing the basic colored denim, reactive dyes are used and fixed with hot
caustic soda solution. The dyeing process is mainly influenced by the dyestuff
characteristics, dyeing temperature and necessary chemicals used in the process. Indigo
dye is the most popular choice as it has good depth of shade and suitable rubbing and
washing fastness. When cotton yarn is dyed with indigo, it leaves a ring-dyeing effect,
because of which the outer layer of warp yarn is coated with indigo, and the core of the
yarn remains undyed. This gives the denim garment a unique ‘faded look’ and a rich blue
shade after repeated use and wash. Originally, the warp yarns or ends were put through
the dye bath side by side to form a sheet of yarn, which passed continuously through
several dye baths, squeeze rollers or airing sequences. However, if there were breaks in
the yarn (and there would be, as each yarn had to take the tension of being pulled through
these processes virtually on its own), the dyeing process had to be stopped. The yarns
would be then mended, or else it would lead to very bad tangling. These stoppages would
in turn cause large shade variations, and the yarn breaks would show up as bad faults in
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the fabric. Now, an infinitely more efficient system has been introduced. Special attention
shall be paid here to Indigo, the „king of dyestuffs” since it plays an important role in
obtaining the jeans effect. Indigo belongs to the category of water-insoluble dyestuffs. It
was first mentioned in a book 13 BC; at that time the name Indian blue indicated the
country the color came from. It is said to have been used for dyeing in India and China
2000 years BC already.
The Indigo plant is used for preparing Indigo
Nowadays, yarn dyeing with indigo is done continuously. Here the various dyeing
processes with different concentrations of chemicals as well as the subsequent yarn sizing
exert an influence on the quality and the appearance of the ready fabric. There are two
processes in the practice for continuous dyeing:
• · Rope Dyeing
• · Slasher or Sheet Dyeing
3.3.1 ROPE DYEING
Indigo Rope Dyeing When dyeing according to the rope dyeing or cable dyeing
method.350 - 400 warp threads are bound on the ball warper to very thick cables of 10
000 - 15 000 m length. On the continuous dyeing installation, 12 to 36 cables are led side
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by side, wetted, dyed and dried after the dyeing process on cylinders and put into cans.
Then the cables are dissolved to warps on the long chain beamer. The warps are added to
the sizing machine, sized and then led together to warp depending on the total numbers of
threads. In practice, this method has proven to be very good through obtaining an
optimum indigo dyeing. However it is important that the cables have a constant tension in
order to avoid warp stripes. The disadvantage compared to other methods is that yarn
breakages do occur more often. Size of the dyeing unit is between 60 - 80 m. Normally, 6
dyeing vats are in use. There are nevertheless variations with 3 to 8 dyeing vats.
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3.3.2 SLASHER DYEING
Indigo Sheet or Double Sheet Dyeing (Slasher Dyeing).When dyeing according to the
sheet dyeing method, instead of cables the warp threads are fed to the machine parallel
next to each other. These are much smaller compared to the rope dyeing machines.
Another advantage is that the cables don’t need to be open after dyeing. Moreover, each
yarn wets much faster and in this way reduces the dipping and wetting times during
dyeing. All in all, each thread has a larger surface compared to a dyeing cable and this
requires somewhat more hydrosulphite to prevent a premature oxidation of the indigo.
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Whereas during rope and sheet dyeing the yarns are always led in succession to the
dyeing baths, the fabric of the loop dye method is led several times through the same
dyeing bath. The machine is then much shorter and the hydrosulphite consumption is
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lower. Depending on the number of dyed passages and the concentration of indigo in the
dyeing vats, different dyeings of the yarn. . [3]
WORKING PRINCIPLE OF SLASHER
Warp beams are brought to the dyeing and sizing section in sheet form as per
requirement. The warp sheet is taken to wetting tank (like mercerize, semi mercerize and
causticize tanks depends upon the dyeing methods) which swells the fiber and increases
its dye uptake. It is then taken to a hot washing tank whose temperature is maintained at
850C. It is then taken to cold washing tank whose temperature is maintained at 600C.
Warp sheet is then taken to dyeing tanks where dye is reduced to soluble leuco form by
using sodium hydrosulfite, yarn is then contacted with the reduced dye, and the dye is
adsorbed by the fibers. The fixed leuco indigo in the yarns of the warp sheet was oxidized
to form pigment during transport of the warp sheet in the air space following the dwelling
chamber, taking approximately 60 seconds. It is taken to two hot washing tanks for
fixation. Following rinsing, warp sheet is dried on cylinders dryers prior to the