Textile dyeing mc final report University of south asia

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Chapter 1
Introduction
Day by day dyeing technology is changing for providing more
coloration facility, more dyeing machine productivity, more upgraded
dyed product, better safety, lower wet processing time, higher quality of
textiles, more consistency of dyes in the textile fabric & finally for
human comfort. In textile wet processing and synthetic dyeing there are
various types of machinery are used from dyeing pretreatment to
finishing which vary with dye brand to brand according to their dyeing
technology. Over the years for textile fabric processing we saw a lot of
development through which we can provide a wide range of textile
product with different coloration appearance & which are used for
different purpose. With the aid of textile machine now most delicate
fabrics with different finish is provided which could not think at past.
Acrylic fibers are dyed with basic dyes, Nylon and protein fibers such as
wool and silk are dyed with acid dyes, polyester yarn is dyed with
disperse dyes. Cotton is dyed with a range of dye types, including vat
dyes, and modern synthetic reactive and direct dyes.

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Chapter 2
2.1 What is textile?
A textile is a flexible material consisting of a network of natural or
artificial fiber (Yarn or Fiber). Textiles are formed
by weaving, knitting, crocheting, knotting, felting, or braiding.
The related words fabric and cloth are often used in textile assembly
trades (such as tailoring and dressmaking) as synonyms for textile.
However, there are subtle differences in these terms in specialized
usage. A textile is any material made of interlacing fibres,
including carpeting and geotextiles. A fabric is a material made through
weaving, knitting, spreading, crocheting, or bonding that may be used in
production of further goods (garments, etc.)
2.2 Etymology and History of textile :
The word 'textile' is from Latin, from the adjective textilis, meaning
'woven', from textus, the past participle of the verb texere, 'to weave'
The word 'fabric' also derives from Latin, most recently from the
Middle French fabrique, or 'building, thing made', and earlier as the
Latin fabrica 'workshop' an art, trade a skilful production, structure,
fabric', which is from the Latin faber, or 'artisan who works in hard
materials', from PIE dhabh-, meaning 'to fit together'

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The first clothes, worn at least 70,000 years ago and perhaps much
earlier, were probably made of animal skins and helped protect early
humans from the ice ages. Then at some point people learned to weave
plant fibers into textiles.The discovery of dyed flax fibres in a cave in
the Republic of Georgia dated to 34,000 BCE suggests textile-like
materials were made even in prehistoric times
The production of textiles is a craft whose speed and scale of production
has been altered almost beyond recognition by industrialization and the
introduction of modern manufacturing techniques. However, for the
main types of textiles, plain weave, twill, or satin weave, there is little
difference between the ancient and modern methods.
2.3 What is Fabric ?
The term fabric can be defined as a planner structure produced by
interlaced/interloped yarns or fibers and felts made by interlocking
fibers. It is a manufactured assembly of fibers and/or yarns that has
substantial surface area in relation to its thickness and sufficient
mechanical strength to give the assembly inherent cohesion. Basically,
there are three methods by which fabrics are made.

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2.4 Types of Fabric :
Generally fabric are three types. They are :
 Woven
Linen Twill Ripstop
 Knitting
Single Jersey Rib Pique
 Non-Woven

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Chapter 3
Woven Dyeing
3.1 introduction
Woven fabric is the intersection of two sets of straight yarns, warp and
weft, which cross and interlace at right angles to each other. The
lengthwise yarns are known as warp yarns and widthwise yarns are
known as weft or filling yarns and the fabric produced is known as
woven fabric.
3.2 Flowchart of woven dyeing

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3.3 Pre treatment of woven dyeing process
3.3.1 SINGEING
Singeing is the first step of dyeing. Singeing is important for a fabric to
provide a smooth finish. Woven fabric goods usually contain protruding
fibers from textile yarns. Singing process is used to remove those
protruding fibres from the surface of the fabric. The fabric is passed in to
a flame and these protruding fibers are burned out. Sometime copper
plate is used remove the fibre. For printing, singing is most essential to
improve the surface smoothness by eliminating the pilling and fibres.
3.3.2 DESIZING
Desizing is an important dyeing preparation step. During weaving sizing
material is used to increase the strength of warp yarn. The sizing
material is hydrophobic in nature. That’s why it must be removed before
dyeing. Desizing is the process to remove the size material from the
fibre. There are many chemical to remove the size material. Enzymes are
the most popular material to use in sizing process.
3.3.3 SCOURING
Scouring is one of the most important processes of textile fabric dyeing.
All of the natural fibre contains natural oil and wax. Before dyeing,
those oil and wax must be clean for smooth and proper dyeing. The
Scouring is a cleaning procedure that used to eliminate those oil, wax

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from fibers, yarns, or fabric by soaping. For scouring process alkaline
solutions are typically used; however, Solvent solution may be used in
some case. The parameter of scouring procedures like temperature,
chemicals, and time vary with the type of fabric and fibre types.
Impurities are including natural materials, dirt lubricants and other.
Residual tints antistatic agents, water-soluble sizes, used for yarn
verification.
3.3.4 BLEACHING
Bleaching is a complex process. The most common bleaching agents
include sodium chlorite, hydrogen peroxide, sulfur dioxide gas and
sodium hypochlorite. All the natural fibre contains a natural color which
is harmful for dyeing shade matching. For example the cotton has
natural yellowish shade. So it is important to remove the natural color
from the fibre. Bleaching is a used to eliminate the natural color from
the fibre and prepare the fabric for further process. According to the
types of fibre the bleaching chemical is selected. Hydrogen peroxide is
most popularly used bleaching agent for cotton and cotton blends.
3.3.5 MERCERIZING
Mercerization is used to increase appearance, luster and dye ability of
textile fibre. Mercerizing is a semi-continuous or continuous chemical
process used for cotton and cotton/polyester goods.Room temperature
must be maintain during this process, causes the twisted ribbon-like

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cotton or cotton polyester blend fabric to swell into a round shape and to
contract in length. This causes the fiber to become more lustrous than
the increase in strength original fiber, by as much as 20 percent, and
increase its affinity for dyes during dyeing.
3.4 Dyeing
Dyeing is proper way to coloration of textile material (fibre, yarn, woven
fabric, knitted fabric, nonwoven fabric). Suitable dyestuff, dyeing
machine and dyes chemical is required for achiving proper dyeing shade.
There are four types of dyeing,
1. Fiber Dyeing
2. Yarn Dyeing
3. Fabric Dyeing
4. Garment Dyeing
3.4.1 BASIC REQUIRMENT OF DYEING MACHINE
 Dyeing machine shall provide sufficient movement for the dyeing
and dyes chemical liquor to penetrate uniformly into every part of
the goods (fiber, yarn, fabric or cloth garments) .
 The dyeing liquor movement inside the dyeing machine shouldn't
be so vigorous that it damages the finer textile materials .

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 Dyeing Machine must be constructed of a material which will
withstand prolonged boiling with acid or alkaline solutions from
the dye bath. .
 Heating arrangement inside the dyeing machine should be such
that uniform temperature could be maintained.
 There should be some means of adding the concentrated dyestuff
solution in such a way that it becomes well diluted before it comes
into contact with the goods.
3.5 Some Woven Dyeing Machine:
35.1 Jet Dyeing Machine
It was found that in using Winch machines, there were some
inherent problems. So the Jet dyeing machines when they came up
in the 1970’s were specifically designed to overcome those
shortcomings. In the Jet dyeing machine the reel is completely
eliminated. A closed tubular system exists where the fabric is
placed. For transporting the fabric through the tube a jet of dye
liquor is supplied through a venturi. The Jet creates turbulence.
This helps in dye penetration along with preventing the fabric from
touching the walls of the tube. As the fabric is often exposed to
comparatively higher concentrations of liquor within the transport
tube, so little dye bath is needed in the bottom of the vessel. This is

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just enough for the smooth movement from rear to front. Aqueous
jet dyeing machines generally employs a driven winch reel along
with a jet nozzle.
The following diagram explains the functioning of a Jet dyeing
machine:
Fig: Jet dyeing machine

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3.5.2 Types of Jet Dyeing Machine
In deciding the type of dyeing machine the following features are
generally taken into consideration for differentiating. They are the
following. Shape of the area where the fabric is stored i.e. long shaped
machine or J-box compact machine. Type of the nozzle along with its
specific positioning i.e. above or below the bath level. Depending
more or less in these criteria for differentiation following types of Jet
Machines can be said to be as developments of the conventional jet
dyeing machine.
A. Overflow Dyeing Machine
B. Soft-flow Dyeing Machine
C. Airflow Dyeing Machine
3.5.3 Advantages of Jet Dyeing Machine
The Jet Dyeing Machine offers the following striking advantages that
make them suitable for fabrics like polyesters.
Low consumption of water
 Short dyeing time
 Can be easily operated at high temperatures and pressure
 Comparatively low liquor ratios, typically ranges between
1:4 and 1:20
 Fabrics are handled carefully and gently.

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3.5.4 Overflow Dyeing Machine
Overflows Dyeing Machines are designed for use in delicate knitted
and woven fabrics that are made up of natural as well as synthetic
fibers. They are also extensively used in the production of carpets.
The main difference between jet and overflows machines is that in jet
machines the fabric gets transported by a bath that flows at high speed
through the nozzle, while in Overflow Dyeing Machine it is the
gravitational force of the liquor overflow that is responsible for fabric
transportation.
A typical Overflow Dyeing Machine works like this. A winch that is
not motor driven usually is located in the top side of the machine
where the fabric is hanged. A longer length of textile is made to hang
from the exit side of the winch as compared to the inlet side. By
applying the force of gravitation the longer length of textile is pulled
downward more strongly than the shorter one. Consequently the fabric
is soaked in the bath without any sort of tension. The following
diagram well illustrates the working process

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A typical Overflow Dyeing Machine works like this. A winch that is
not motor driven usually is located in the top side of the machine
where the fabric is hanged. A longer length of textile is made to hang
from the exit side of the winch as compared to the inlet side. By
applying the force of gravitation the longer length of textile is pulled
downward more strongly than the shorter one. Consequently the fabric
is soaked in the bath without any sort of tension. The following
diagram well illustrates the working process

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3.5.5 Advantages of Overflow Dyeing Machine
No evaporative losses- As the dyeing vessel is closed, there is no
evaporative losses
 stemming from the dye bath. Further, depending on the situation the
temperature may be raised to more than 1000oC. No buildup of steam
condensate in the dye bath- The latest technology implies that
 the dye bath gets heated by a heat transducer which is steam driven.
This technology apart from being very efficient ensures that there is
no buildup of steam condensate in the dye bath.
Low liquor ratios- Dyeing is conducted at relatively low liquor ratios,
e.g. 10:1 and
 may be lesser resulting in substantial savings in water and energy.
Excellent dye liquor contact- Excellent dye liquor contact with the
fabric rope
 results in better and more improved level dyeing. Computer control-
The machines are operated by computer and hence, operator error is
eliminated.
3.5.6 Airflow Dyeing Machine
This is another development of the very popular jet dyeing machines.
The main difference between the Air Flow Machine and Jet Dyeing
machine is that the airflow machine utilizes an air jet instead of the

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water jet for keeping the fabric in circulation. Typically the fabric is
allowed to pass into the storage area that has a very small amount of
free liquor. This results in a reduction in consumption of water, energy
and chemicals. The figure below shows how in an Airflow Machine
the bath level is always under the level of the processed textile. Here
the fabric does not remain in touch with the liquor (the bath used is
below the basket that holds the fabric in circulation). This invariably
means that the bath conditions can be altered without having any
impact on the process phase of the substrate.
Fig : Airflow Dyeing Machine

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3.5.6.1 Advantages of Airflow Machine
 Completely Separated circuit for liquor circulation without getting
in touch with the textile Bath
 Less Dyeing operation
 Rinsing process offers all the added benefits of continuous
processing as it is no longer a
batch operation
 Extremely low liquor ratio
 Virtually nonstop process
 Comparatively lesser energy requirement due to faster
heating/cooling and optimum
heat recovery from the hot exhausted dye liquors
 Reduction in consumption of the chemicals
(e.g. salt) dosage of which is based on the amount of dye bath
 Lesser water consumption savings up to 50% from the conventional
Jet dyeing machines
 Sensitivity towards ecology
 Economical operation
 More safety while dyeing

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3.6 Jigger dyeing machine
Based on experience and developments in industry and controller
technology, the Jigger is developed. Suitable for processing fabric at
atmospheric temperatures of up to 98°C and in HT execution up to
143°C, this Jigger is especially recommended for the treatment of
crease sensitive, permeable and non-permeable articles in open width
form, offering optimum flexibility for the finishing of all modern
fibers and blends. Incorporating innovations in step less tension and
material speed control and with an economical dye trough designed
for uniform dyeing in short liquor ratio conditions.
An industrial PC, proven in the exhaust dyeing industry, including
PLC and a fabric rope monitoring system is used for the complete
machine control, ensuring the maintenance of optimum processing
conditions.
3.6.1 Significant innovations in the process technology ensure
modern utilization
1. Direct drive of the main rollers via frequency controlled three-phase
motors with brake drive current return (energy saving)
2. A dye trough design ensuring minimum possible liquor ratio

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3. Fabric rope monitoring control system for precise calculation and
control of the fabric speed
and tension
4. Uniform dyeing conditions in the dye trough, independent of the
batch size
5. Water meter for controlled rinsing
6. Dosing of dyes and chemicals dependent on the fabric length
passing through the dye bath
7. Addition pressure pump for shading corrections and dosing
8. On the HT-Jigger dosing under pressure possible
9. External pump and heat exchanger ensure uniform liquor heating
and circulation
10. Sidewise displacement of the main batch roller
11. Analogue level for dyeing kier
12. Floor level track system*
13. Easy maintenance
Fig : Jigger dyeing machine

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3.6.2 High-temperature High-pressure Auto jigger dyeing
Machine
This machine is for the jig dyeing at high temperature and high
pressure conditions of all types of thick, thin fabrics, Terylene,
chemical fiber and real silk fabrics. Under normal temperature and
pressure conditions, it can replace common jigs to dye all types of
natural silk, rayon and polyamide fiber. The machine is reasonably
structured, with good safety and capacity, easy to maintain.
Major Technical Parameters
 Roller diameter 219mm
 Max. Rolling width 1800mm
 Max. Rolling diameter 680mm
 Working speed 40-110m/min
 Max. Pressure 0.28MPa
 Max. Temperature 140
3.6.3 Limitations of Jigger Dyeing
1. Jigs exert considerable lengthwise tension on the fabric and are
more suitable for the dyeing of woven than knitted fabrics.
2. In textile preparation due to the swelling and dissolution of size,
this makes the fabric slippery and unstable in roll form.
3. The low liquor ratio makes washing-off difficult.

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4. There is little mechanical action in a jig machine and it is less
suitable where vigorous scouring is required before dying.
5. Moir effects or water marks may arise on some acetate and nylon
fabrics because of pressure flattening the structure of the rolled fabric.
3.7 Winch Dyeing Machine
Winch dyeing machines comes with the lucrative options of low cost
design, simplicity in operation and maintenance yet uncompromising
features when it comes to versatility. Mostly woolen fabrics are dyed
by using Winch Dyeing machine. The dyeing machine derives its
name "Winch" as the fabric rope gets circulated in the machine by
way of a mechanical action of a horizontal rotor or reel, called as a
winch or sometimes winces. The cross-section of the winch rotor may
be circular or elliptical. As shown in the diagram below, the winch
dyeing machine has a front compartment; a perforated partition
separates it from the main dyeing chamber. It is this front
compartment where dyestuff and dyeing auxiliary additions are made.
Gradually they move to main dyeing vessel from there. The process
works like this first a series of fabric ropes are immersed in the dye
bath. This fabric ropes must be of equal lengths. A part of each rope is
then taken over two reels or over the winch itself. In the subsequent
course of dyeing operation a rope of fabric is circulated through the

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dye bath and the winch. The dyestuff and auxiliaries are dosed
manually or automatically according to the recipe method.
Fig: Winch Dyeing Machine
3.7 Features: -
Width the wide soft nozzle. It plans a soft the hazard which gets a soft
process wide and soft nozzle system especially.
Air parts system(the selective evening sunlight): It is tied with the
system which pours an air in the knit fabric which has not become dog
width, the back which is entangled it prevents and also the quality
improves.

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The work characteristic which excels: The mechanical structure is
simplicity the excellent work and irrigation to be easy and the
American expert the work is possible.
Width wide application : Reel [li] and other it will come, Oh, the
wool, the cotton and the pulley Oh America [tu], the acryl, the viscose
and the pulley nose the product back which sprouts dyeing, bleaching
and washing the product which is various are possible with the bell.
Performance Mechanism: Wide and soft nozzle. The special designed
wide soft flow nozzle system with high liquor flow to achieve the soft
and smooth process.
Air ballooning system (Option): Air ballooning device which are to
be shoot air in the tubular type knitted fabrics so that fabric can be dye
at any condition. Excellent Workability: The compact structure of
machine provides easy operation and maintenance and even the
unskilled.
Wide Application: The machine provides multi-purpose of dyeing and
bleaching and washing for terry towel, velour, wool, cotton,
polyamide, acrylic and viscose and poly/cotton brand and so on.
Technical Characteristics:
Capacity (kg): 400 ~ 450
Electric power: 18kw
Max temp: 98 °C
Number of nozzle: 4

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3.8 Beam Dyeing Machine
The beam dyeing machine operates with the same principle as that of
package dyeing machine. It can be effectively used to dye yarn or
fabric. The process works like this, fabric or yarn in open width is
rolled on to a perforated beam. The beam then subsequently slid into a
vessel that is closed and pressurized. The color impregnates the fabric
as the dye liquor is allowed to go on circulating through the
perforations in the beam. Usually the beam machines are designed in
such a manner so as to hold a single beam or multiple beams in a
batch.
Fig: Beam Dyeing machine

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3.8.1 Features of Beam dyeing Machine
Able to adjust water level in accordance to fabric volume
. Even dyeing and superior dyeing quality
. Optimized circulation system along with high performance pumps.
3.8.2Advantages of a Beam Dyeing Machine
The fabric is put under controlled tension, and is wound on to a
perforated beam.
 This results in elimination of creases from the fabric. It also
ensures total control of dimensions of the roll of fabric.
 The fabric is not allowed to do any movement during the
process of dyeing. This actually means that there is no
application of mechanical action on to the fabric.
3.8.2 Technical Specification of the featured model
Loading Cap: 100 kg
Electric wattage: 22Kw
Maximum Operating Pressure: 5kgf/cm2g
Maximum Operating Temperature: 158°C

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3.9 Dyeing Process
3.9.1 DYEING PROCESS OF COTTON FABRIC WITH
REACTIVE DYES
Dyeing process is the process of giving of colour at textile material
equally (uniformly)
. In principle mechanism of dyeing process consists of 3 steps:
1. Migration dyestuff towards fibre.
2. Adsorption molecule dyestuff at surface of fibre.
3. Diffusion dyestuff from surface of fibre to fibre interior.
To get good result hence there are 6 important thing which must be
taken care of :
1. Hardness of water
2. Chemicals balance (dyes, auxiliaries, salt, alkali)
3. Liquor Ratio (comparison of water with fabric weight)
4. pH dye solution (beginning of process and phase process of
fixation )
5. Dyeing temperature
6. Dyeing time

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3.9.2. 100% cotton fabric can be dyed with following types of dyes: -
- Reactive Dyes
- Direct Dyes
- Sulphuric Dyes
- Vat Dyes
- Pigment Dyes
Among some of the above dyes, reactive dye is most applied at 100%
cotton fabric good in the form of knitted fabric or woven fabric.
3.9.3. Reactive dye is applied for following reasons:
1. Simple dyeing process.
2. Choice of more colours available
3. Good colour resilience Based on its reactivity,
reactive dyes are divided into 2 types, that is:
1. Hot reactive dyes Reactive dyes which have low reactivity
2. Cool reactive dyes
3.Reactive dyes which have high reactivity
Reactive Dyes are applied to for following reasons: -
Good dye condensation
- Good colour resilience
- Dyeing at hot temperature so that penetrating of dye into fibre is
better
- Have good levelness of dyeing result

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- Have choice of complete colour
- Easier process control
- Very suited for mercerized cotton cloth
- Generally resistant to process “ post bleach ”
Principle
In principle process of dyeing 100% cotton knitted fabric with reactive
dye is with circulation material textile with dye solution and some
auxiliaries, with certain concentration, certain time and certain
temperature applies of dyeing machine.
3.9.4 PROCESS OF DYEING WITH HE TYPE REACTIVE DYES
WITH EXHAUST DYEING SYSTEM
1. METHOD SALT ADDITION STEP BY STEP: This method is
suited for all dyeing colours and for machine in which dyeing solution
do not have circulation, for example Winch machine.
2. METHOD ADDITION SALT IN THE BEGINNING OF
PROCESS (SALT-AT-START): This method is more compatibly
applied for dyeing colour from medium to depth colour and for

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machine with dyeing solution circulation and it’s the textile material,
the example jet dyeing machine, jet flow machine.
Example of dyeing recipe for red colour:
- Reactive Orange HER 2.0 %
- Reactive Red HE-7B 1.5 %
- Glauber salt 70 g/l
- Soda Ash 20 g/l
- Dispersing
-sequestering agent 1 – 2 g/l
- Anti crease mark agent 1 – 2 g/l
- Anti foam agent 1 g/l
Liquor Ratio 1: 10
Temperature 80 0C
The time 60 minute
Jet dyeing machine

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Auxiliaries and its function
1. SALT (GLAUBER SALT / SULPHATE SODIUM / Na2SO4)
Function to increase absorption of reactive dye into fibre
2. ASH SODA (CARBONATE SODIUM / Na2CO3)P:
Function to react dye with fibre (fixation)
3. DISPERSING-SEQUESTERING
Functions to tie metal ion (iron, calcium, copper, magnesium and
other) which is in the dyeing solution be so that got by colour better
dyeing result. Besides functioning to increase reactive dye solution in
high rate electrolyte.
4. ANTI CREASE MARK AGENT
Functions to prevent incidence of crease-mark / rope mark
( piebald of fold ) during process of dyeing takes running.
5. ANTIFOAM AGENT
Functions to eliminate foam arising during dyeing process because it
can cause piebald dyeing colour and colour scraggly. Foam arises from
water circulation and material which quickly by, also from auxiliaries
which can generate foam. Too much foam can result in machine stuck.

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3.10. WASHING PROCESS
There are 4 phase process of wash which is done after dyeing process :
 Hot rinsing before soaping process
o Eliminate or drop concentration of salt and alkali as many as
possible
o Avoid from the happening of precipitation of reactive dye
o Eliminate the happening of wrinkling line at fabric as result
of degradation of dyeing temperature solution which would
throw.
 2. Soaping: Eliminate reactive dye pickings which is hydrolysis
by nit and is not Fixation / reacts with fibre
o Increase power reactive dye diffusion to exit from surface of
fibre
 3. Hot rinsing after soaping.
o Help to prevents reactive dye pickings to return to surface of
fabric ( back staining )
 Phase of washing process for light colour fabric, medium colour
and deep of colour
 LIGHT COLOUR (dyes < 1%, concentration of salt < 30 g/l )
o Hot rinsing (70 0C, 10 minutes)

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o Soaping (95 0C, 10 minutes)
o Cold rinsing (30 0C, 10 minutes), overflow
 MEDIUM COLOUR (dyes 1 – 4 %, concentration of salt 30 – 60
g/l )
 DEEP OF COLOUR (dyes > 4%, concentration of salt > 70 g/l)

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3.10.1 - Fixing process FIXING PROCESS:
For medium colour and deep colour the process fixing by using
of fixing agent. Fixing agent functions for :
1. Strengthen strong tying dye with fabric fiber.
2. Increase resilience cleans fabric.
Process of workmanship with fixing agent:
 Fixing agent 1 – 2 % (medium colour) or 2 – 3 %
(deep colour)
 pH 5
 Temperature 50 – 60 0C
 Time 20 minutes After completing in cold rinsing
then dried.
3.11 Some woven dyeing machine and their manufacturer
Fig : Singeing Machine

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Fig : Singeing Machine
Fig : De-sizing Machine

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Fig :Scouring Machine
Fig: Open Width Scouring Machine

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Fig : Bleaching Machine
Fig : Bleaching Machine

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Fig :Mercerizing Machine
Fig: Fabric Dyeing Machine

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Fig: Fabric Dyeing Machine
Fig: Fabric Finishing Machine

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Fig: Fabric Finishing Machine
Fig: Fabric Inspection Machine

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Fig : Some Machine Manufacturer List

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Chapter 4
Knitting Fabric
4.1 Introduction
Knit fabric consists of forming yarns into loops, each of which is
typically only released after a succeeding loop has been formed and
intermeshed with it so that a secure ground loop structure is achieved
4.2 Flowchart of knitting dyeing

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4.3 Pretreatment of Knit Dyeing
4.3.1Grey fabric inspection
The inspection and grading of fabric quality is all of the important
function of quality control in the grey or finished state. The grading
has two primary function, First to classify the fabrics according to
standard qualities based on the end use and customers demands,
Second To supply information as to the qualities actually being
produced.
Knitted fabric can be classified into three levels of quality, each one
have a number of point for defects as follows
1. The first quality level : 40 points per 100 linear yards
2. The Second quality level : 40 to 80 points per 100 linear yards
3. The Third quality level : 80 points or more per 100 linear yards
4.3.2 Heat setting
Heat setting is a heat treatment by which shape retention, crease
resistance, resilience and elasticity are imparted to the fibers. It also
brings changes in strength, stretch ability, softness, dye ability and
sometimes on the color of the material. All these changes
are connected with the structural and chemical modifications
occurring in the fiber. Normally heat setting done for lycra fabric.

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4.3.3 Batching
Batching is the receiving section of grey fabric and sending section
of grey fabric to the dyeing section which will dye. Batching is
the process to get ready the fabrics which should be dyed
and processed for a particular lot of a particular order.
Batch Process Flow Chart:
Flow chart of Batching Section is given bellow:
Fabric Received & stored
↓
Fabric Divided according to Diameter after buyer’s recommendation
↓
Supervisor batches the fabric according to quantity by Calculation
↓
Inspection
↓
Send for Dyeing

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4.3.4 SCOURING
Scouring is one of the most important processes of textile fabric dyeing.
All of the natural fiber contains natural oil and wax. Before dyeing,
those oil and wax must be clean for smooth and proper dyeing. The
Scouring is a cleaning procedure that used to eliminate those oil, wax
from fibers, yarns, or fabric by soaping. For scouring process alkaline
solutions are typically used; however, Solvent solution may be used in
some case. The parameter of scouring procedures like temperature,
chemicals, and time vary with the type of fabric and fiber types.
Impurities are including natural materials, dirt lubricants and other.
Residual tints antistatic agents, water-soluble sizes, used for yarn
verification.
4.3.5 BLEACHING
Bleaching is a complex process. The most common bleaching agents
include sodium chlorite, hydrogen peroxide, sulfur dioxide gas and
sodium hypochlorite. All the natural fiber contains a natural color which
is harmful for dyeing shade matching. For example the cotton has
natural yellowish shade. So it is important to remove the natural color
from the fiber. Bleaching is a used to eliminate the natural color from
the fiber and prepare the fabric for further process. According to the
types of fiber the bleaching chemical is selected. Hydrogen peroxide is
most popularly used bleaching agent for cotton and cotton blends.

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4.3.6 MERCERIZING
Mercerization is used to increase appearance, luster and dye ability of
textile fiber. Mercerizing is a semi-continuous or continuous chemical
process used for cotton and cotton/polyester goods. Room temperature
must be maintain during this process, causes the twisted ribbon-like
cotton or cotton polyester blend fabric to swell into a round shape and to
contract in length. This causes the fiber to become more lustrous than
the increase in strength original fiber, by as much as 20 percent, and
increase its affinity for dyes during dyeing.
4.4 Dyeing Process
Knit dyeing is a technique of dyeing the knitted fabrics. The dyeing of
knitted fabrics occurs in the exhaust method or in batch-wise process.
Generally all type of single jersey, double jersey and their derivatives
are dyed by the following process.
4.4.1 Machines used in dyeing process of knitted fabrics
 Winch dyeing machine
 Jet dyeing machine
 Jig dyeing machine
 Paddle dyeing machine
 Soft flow dyeing machines

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4.4.2 Dyeing through winch dyeing machine
Knit goods are generally dyed in the roller piece form and slit(To cut
lengthwise into strips) lengthwise after dyeing. Warp knits have the
tendency to curl at the edges, hence several rolls are tied together so
they are dyed in tubular form. Forming a long chain, the number of
rolls to the chain being dependent on the weight of the fabric. When
dyeing of tubular fabric is carried out in winches, air bubbles are
Collected inside the tube form immediately below the jockey roll. The
bubble is continuously pushed back along the rope by the jockey roll.
The dyeing machine employed consist of a tub provided with a
revolving winch on top. The winch is made up of wood. The chains of
cloth are passed over the winch and circulated through the dye liquor
in the tub below. Usually from eight to twelve chains are run in one
machine side-by-side. As the goods come up from the liquor they are
passed from a set of small squeeze rollers and then run on the
revolving winch. The squeeze rollers and the winch should be so set
and run at such relative speeds that there is as little tension on the
cloth as possible, as the tension while the cloth is running in the
dyeing operation tends to stretch the goods out of shape and also
materially reduce their elasticity. The speed of the squeezing rollers is
somewhat high than that of the winch. The winch is fluted so that less
surface area of the fabric touches the winch and hence low tension is
created on the fabric. The machine employed for the dyeing process is

MTM 404 Page 46
similar in every respect to that employed for wetting-out or scouring
process. Unless a number of lots to be dyed, the goods may be rinsed
off in the machine used for dyeing, by simply running off the dye
liquor and refilling with fresh water.
Fig : Winch Dyeing Machine

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4.4.3 Piece-Dyeing
Piece dyeing occurs in the winch dyeing machine. Most textured
polyesters is piece-dyed which are manufactured through knitting.
Some continuous scouring machines are built to handle knitted fabric
with controlled tension. Although one machine is more suitable than
other, the depends on many factors, including the type of fabric to be
processed, machine tension, method of extraction and efficiency of oil
and dirt removal. This last factor is especially important. High
temperature dyeing units generally operates at temperatures between
230 and 260 F. This makes possible shorter dyeing cycles with little or
no carrier cost. It also improves quality, barre and shading piece to
piece. In spite of high capital costs, there are definite advantages to
high temperature dyeing.
Fig : Piece Dyeing Machine

MTM 404 Page 48
4.4.4 Dyeing through Jet dyeing machines
Jet dyeing machines resemble becks in that a continuous loop of
knitted fabric is circulated through the machine. However, the cloth
transport mechanism is dramatically different in these two types of
machines. A high speed jet of dye liquid created by a venture
transports the fabric through the cloth guide tube of the jet machine. A
jet machine has a cloth guide tube for each loop of fabric being
processed. A powerful pump circulates the liquor through a heat
exchanger outside of the main vessel and back into the jet machine.
The fabric travels at high velocity of 200-800 meters per minute while
it is in the cloth guide tube. The fabric leaving the cloth guide tube
enters a larger capacity cloth chamber and gradually advances back
toward the cloth guide tube. Pressurizing a jet dyeing machine
provides for high temperature dyeing capability. High temperature jet
machines are especially suitable for delicate fabrics made of texturized
polyester. Some atmospheric
machines designed for dyeing temperatures up to 100 C also use the
jet circulation principle.

MTM 404 Page 49
Fig: Jet Dyeing Machine for Knit Fabric

MTM 404 Page 50
4.4.5 Space dyeing of knitted fabrics
Polychromatic method can be used to produce a wide variety of
patterns in many shades on knitted fabrics. Two or three set of jets
apply the dye liquor to the goods passing below the jets. The
individual jets can be connected with dye liquors of different colors by
means of a special dyestuff supply tube. A sheet called mirror is
placed at an angle below the jets. The angle is so adjusted that the
liquid stream coming from or two series of jets produces changes in
color pattern and mixtures. After applying a constant amount of
liquor, which must be fixed beforehand by a suitable choice of jet size,
the goods are through a padder, when the final pattern is obtained. The
goods are than steamed continuously, washed and dried.
Fig : Space Dyeing Machine

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4.5 The effect of temperature on dyeing of knitted fabrics
Two fabrics are dyed A and B using standard and varied temperature
respectively. When the effect of dyeing temperature was studied, the
comparisons between samples B and A (as standard) were done.
Temperatures varied 30-50 °C, applied ultrasound frequency was 40
kHz, while the quantity of added NaCl was 60 g/dm3
. The results of
color differences between samples B and A present that the sample B
is darker at temperatures of dyeing from 30 °C to 50 °C yellow and
more redder at dyeing temperature 50 °C. The same sample is greener
and bluer when the temperatures of dyeing are 40 °C and 30 °C. When
the effect of dyeing temperature was studied, the comparisons
between samples D and A (as standard) were done. Temperatures
varied from 60 to 40 °C, applied ultrasound frequency was 40 kHz,
while the quantity of added NaCl was 60 g/dm3
. Regarding the results
of color differences between samples D and A (not shown), it appears
that the sample D is darker at temperature of dyeing from 60 °C to 40
°C; redder and more yellow (0.8) at dyeing temperature 40 °C. The
same sample is greener and bluer when the temperatures of dyeing are
60 °C and 50 °C. Total color differences satisfy two allowed criteria
M&S and CMC for applied temperature 50 °C

MTM 404 Page 52
4.6 Knit Fabric Finishing
Finishing is a general term which usually refers to treatment on textile
fabrics
o after dyeing or printing. It increase life and durability of the fabric.
o By finishing we can maintain fabric shape and size.
o Finishing accentuate or inhibit some characteristic of fabric Impart
new characteristic or properties
o Finishes may be done by chemically or mechanically.
o To get good finished quality we should maintain machine
parameter or proper
o chemical recipe. We can improve finished product quality by
developing machine parameter
o create new and appropriate chemical recipe.
4.6.1 Types of finishing
Types of finishing The most common classifications:
 Aesthetic finishes
 Functional finishes

MTM 404 Page 53
Finishes also classifies:
4.6.2 Process Flow Chart of Finishing Section:

MTM 404 Page 54
4.7 Some finishes knit fabric
1.Mechanical Finishing:
Involving the application of physical principles such as friction,
temperature, pressure, tension and many others.
Calendaring
A process of passing cloth between rollers (or "calendars"), usually
under carefully controlled heat and pressure, to produce a variety of
surface textures or effects in fabric such as compact, smooth, supple, flat
and glazed. The process involves passing fabric through a calendar in
which a highly polished, usually heated, steel bowl rotates at a higher
surface speed than the softer (e.g. cotton or paper packed) bowl against
which it works, thus producing a glaze on the face of the fabric that is in
contact with the steel bowl. The friction ratio is the ratio of the
peripheral speed of the faster steel bowl to that of the slower bowl and is
normally in the range 1.5 to 3.0. The normal woven fabric surface is not
flat, particularly in ordinary quality plain weave fabrics, because of the
round shape of the yarns, and interlacings of warp and weft at right
angles to each other. In such fabrics it is more often seen that even when
the fabric is quite regular, it is not flat. During calendering, the yarns in
the fabric are squashed into a flattened elliptical shape; the intersections
are made to close-up between the yarns. This causes the fabric surface to
become flat and compact. The improved planeness of surface in turn

MTM 404 Page 55
improves the glaze of the fabric. The calender machines may have
several rollers, some of which can be heated and varied in speed, so that
in addition to pressure a polishing action can be exerted to increase
lustre.
Compacting
Durable finish imparted on man-made fibres and knitted fabrics by
employing heat and pressure to shrink them to produce a crêpey and
bulky texture.
Embossing
This particular type of calendaring process allows engraving a simple
pattern on the fabric. To produce a pattern in relief by passing fabric
through a calendar in which a heated metal bowl engraved with the
pattern works against a relatively soft bowl, built up of compressed
paper or cotton on a metal centre.
Sueding
This process is carried out by means of a roller coated with abrasive
material. The fabric has a much softer hand and an improved insulating
effect thanks to the fibre end pulled out of the fabric surface.

MTM 404 Page 56
Raising
The raising of the fibre on the face of the goods by means of teasels or
rollers covered with card clothing (steel wires) that are about one inch in
height. Action by either method raises the protruding fibres and causes
the finished fabric to provide greater warmth to the wearer, makes the
cloth more compact, causes the fabric to become softer in hand or
smoother in feel; increase durability and covers the minute areas
between the interlacing of the warp and the filling. Napped fabrics
include blankets, flannel, unfinished worsted, and several types of
coatings and some dress goods. Other names for napping are Gigging,
Genapping, Teaseled, Raised.
Steaming
It is done by using high temperatures to stabilize fabrics containing
polyester, nylon, or triacetate but not effective on cotton or rayon.it may
be performed in fabric form or garment form it may cause shade
variation from side-to-side if done prior to dyeing; may change the shade
if done after dyeing

MTM 404 Page 57
Sanforizing
Sanforizing is a process where by the fabric is run through a sanforizer;
a machine that has drums filled with hot steam. This process is done to
control the shrinkage of the fabric.The fabric is given an optimum
dimensional stability by applying mechanic forces and water vapour.
Fulling:
The structure, bulk and shrinkage of wool are modified by applying heat
combined with friction and compression.
2. Chemical Finish
The finishes applied by means of chemicals of different origins, a fabric
can receive properties otherwise impossible to obtain with mechanical
means.
Enzyme
Bio polishing, also called bio-finishing, is a finishing process applied to
cellulosic textiles that produces permanent effects by the use of
enzymes. Bio-finishing removes protruding fibres and slubs from
fabrics, significantly reduces pilling, softens fabric hand and provides a
smooth fabric appearance, especially forknitwear and as a parameter for
printing.

MTM 404 Page 58
Chapter 5
Some buyer list

MTM 404 Page 59
Chapter 6
Conclusion
Now days Dyeing are an essential part of modern Textile. The desire to use textile
fabrics as a carrier of designs for decoration or identification has existed for many
centuries. The development of modern equipment and colorant technology has
enabled textile manufacturers to be able to reproduce highly colored textile designs
with excellent colorfastness. This can be performed on a wide variety of fibers and
fabric constructions, employing cost effective processes.
However, as good as textile-dyeing technology is today, the processes are
continuing to improve. New technologies and new developments in existing
methods promise to continue the expansion of the capabilities of textile dyeing
well into the future.

MTM 404 Page 60
References
https://en.wikipedia.org/wiki/Textile
https://www.slideshare.net/tanvir38/woven-dyeing-process?from_action=save
http://textilelearner.blogspot.com/2012/07/what-is-fabric-warp-weft-fabric.html
http://textilelearner.blogspot.com/2011/12/methods-of-dyeing-different-
dyeing.html
https://www.fibre2fashion.com/industry-article/7091/dyeing-process-of-jigger-
dyeing-machine?page=2
http://textilefashionstudy.com/four-point-systems-for-knit-fabric-quality-
measurement/
http://www.textiletoday.com.bd/magazine/
http://textilefashionstudy.com/process-flow-chart-of-knit-fabric-dyeing-with-
reactive-dyes/
https://www.scribd.com/doc/54185948/Textile-Dyeing-and-Printing

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