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FD4006: TEXTILE SCIENCE AND TECHNOLOGY
SEMESTER III
B.DES.

UNIT II
PART 1- STAGES OF DYEING

17/09/2024 3
Content��.
?Introduction
?Stage of dyeing
?Dyeing types and it��s Process, Effects on fabrics, Advantage, And
Use Of Different Preparatory.
?Processes Done On Textiles For The Dyeing And Printing: Singeing,
Desizing, Boiling, Scouring, Souring, Bleaching and Mercerization.
FOUZIA MIRZA

17/09/2024 FOUZIA MIRZA 4
INTRODUCTION.
https://
www.youtube.co
m/watch?
v=QHgNoSYlhYs
https://
www.youtube.com
/watch?
v=9OHbJQ90hfY

Video Links
?Cotton : https://www.youtube.com/watch?v=QHgNoSYlhYs
?Linen: https://www.youtube.com/watch?v=-ZrZZefkohE
?Silk : https://www.youtube.com/watch?v=b8rX5DRusNI
?Polyester: https://www.youtube.com/watch?v=zYkglUysDKk
?Weaving: https://www.youtube.com/watch?v=worKmsWZqYE
? Handloom: https://www.youtube.com/watch?v=LBTRkaq0rFM
? Powerlooms: https://www.youtube.com/watch?v=TyhDkd8Iabs

Video Links
?Shearing and cropping: https://www.youtube.com/watch?v=shPjEYi1zlM
?Singeing: https://www.youtube.com/watch?v=StcDo7Y1Eeg
?Desizing: https://www.youtube.com/watch?v=BidcXjaQUd8
?Scouring: https://www.youtube.com/watch?v=pWGzTVI24gA
?Dyeing ( Tie- Dyeing): https://www.youtube.com/watch?v=8R4lAladUj0
?Dyeing: https://www.youtube.com/watch?v=8R4lAladUj0

CLASSIFICATION OF
TEXTILE FIBRE

INTRODUCTION OF WET PROCESSING.

INTRODUCTION OF WET PROCESSING.
?The wet processing is a term that involves the mechanical and chemical
treatment to improve the aesthetic value of the fabric, yarn, fiber.
?The wet processing sector can be divided into three distinct sections.
I. Preparatory process.
II. Coloration process.
III. Finishing process.
?Lastly Inspection and shipping

Dyeing
and
Printing
Shearing
and
Cropping
Grey
Stitching
Singeing
Mercerizing
Bleaching
Scouring
Desizing
Finishing
Final
Inspection

Singeing
For Dyeing
and
Printing
Pre-treatment Process
? Pre-treatment processes can be carried
out with fibres, yarns or fabrics.
? It enables subsequent processing of the
material, which needs to be prepared to
accept dyes and functional chemicals.
? This is done in a multi-step process.
? Exactly which steps the fabric goes
through depends on the type, or blend of
fibre, and how it will be treated
afterwards.
? In some cases pre-treated fabrics are
manufactured for later garment dyeing

Basic Textile Terms and Definitions
?Dyestuff is organic or inorganic substances which can absorb light
and reflect some lights to show color. Actually, the dyestuff is water
soluble substances.
?Pigment is a substance that can absorb light and reflect some lights
to show color but it is water insoluble substances. Normally it is used
for printing (with the presence of binder) or mass-coloration of the
synthetic fibers.

Dye Structure
Chromophore
Responsible for providing colors
Auxochromes
Responsible for forming Chemical bond with textile material

Stages of Dyeing
Stages of Dyeing
Fibers
Stock Dyeing
Top Dyeing
Dope Dyeing
Yarns
Skein Dyeing
Package Dyeing
Beam Dyeing
Fabrics
Piece dyeing
Resist dyeing
Printing
Garments
Garment dyeing

Different Stages of Dyeing Textiles
?Textiles may be dyed at any stage of their
development from fibre into fabric or certain
garments by the following methods;

Stock Dyeing
?Stock dyeing refers to dyeing staple fibres before they are
spun.
?Here the packed fibres are removed from the bales and
then packed in large vats to be circulated with dye liquor
at elevated temperature.
?In stock dyeing, which is the most effective and expensive
method of dyeing, the colour is well penetrated into the
fibres and does not crack readily.
?Stock dyed fibres does not spin as readily as undyed fibre
because it loses some of its flexibility, but lubricants added
in the final stage overcome most of this difficulty.

Solution pigmenting or Dope dyeing :
? A process called solution pigmenting or dope dyeing has been used
for manmade fabrics ranging from rayon through saran and glass
fibres.
?In dope dyeing, dye is added to the spinning solution before it is
extruded through the spinnerets into filaments.
? This method also gives a greater degree of color fastness.
?Effective results have been obtained by this method.

Top dyeing
?Top dyeing is adopted in the worsted industry.
?Top is wool that has been combed to take out the short fabrics, in a
rope like form about 1.2 inches (30mm thick).
?The top is then wound on perforated spools and the dye liquor is
circulated through it.
?Perfect even dyeing is possible in this method.

Yarn Dyeing
?Dyeing done at yarn stage is known as yarn dyeing. Yarn
dyed fabrics are usually deeper and richer in colour.
?The primary reason for dyeing in the yarn form is to create
interesting checks, stripes and plaids with different
coloured yarns in the weaving process. Some typical yarn-
dyed fabrics are multi colored gingham, madras, brocade
and multi-colored weft knits. Yarn dyeing is also used in
special cases for solid-color fabrics.
?Yarns may be dyed in different forms such as, Skeins,
Packages and Beams.

Yarn Dyeing
Skein Dyeing
Skein Dyeing consists of immersing large, loosely wound hanks (skeins) of
yarns into dye vats that are especially designed for this purpose. Soft, lofty
yarns such as hand knitting yarns are usually skein dyed. Skein dyeing is the
most costly yarn-dye method.
Package Dyeing
In Package Dyeing, yarn is wound on a small perforated spool or tube called a
package. Many spools fit into the dyeing machine in which the flow of the dye
bath alternates from the centre to outside, and then form outside to the
centre of the package.

Yarn Dyeing
Beam Dyeing
Beam Dyeing is a much larger version of package dyeing. An entire
warp beam is wound onto a perforated cylinder, which is then placed
in the beam dyeing machine where the flow of the dye bath
alternates as in package dyeing.

Fabric Dyeing
Piece Dyeing :
? Bulk of fabrics are dyed in this method. Piece dyeing is thoroughly
satisfactory as regards evenness, penetration and overall fastness.
?Fabrics may be piece dyed whether it is composed of only one kind of
fibre or yarn or blends of different fibres or combinations of different
yarns.
?When the fabric is made of one kind of fibre or yarn, the dyeing is not
complicated because the one appropriate dye is used.

Fabric Dyeing
?If the fabric is of a blend or combination of different yarns, then
special procedures are required where different dyes that are
particular for each fibre need to be selected.
?They are union dyeing and cross dyeing.
Union Dyeing: Different fibres may require different dyes to obtain
the color, this may be done by putting the appropriate colour dye
that is specific to each type of fibre into one bath.
Cross Dyeing: Cross dyeing of goods may be accomplished in any
one of the several ways. One method is a combination of stock
dyeing or of yarn dyeing with subsequent fabric dyeing.

Garment Dyeing
?Garment Dyeing is the dyeing of completed garments. The types of apparel
that can be dyed are mostly non-tailored and simpler forms, such as
sweaters, sweat-shirts, T-shirts, hosiery, and pantyhose. The effect on sizing,
threads, zippers and snaps must be considered. Tailored items such as suits
or dresses cannot be dyed as garments because the difference in shrinkage
of the various components and linings distort and miss-shape the article.
?Garment dyeing is done by placing a suitable number of garments (usually
about 24 sweaters or the equivalent, depending on weight) into a large
nylon net bag. The garments are loosely packed. From 10 to 50 of the bags
are placed in large tubs containing the dye bath and are kept agitated by
a motor driven paddle in the dye tub. The machine is appropriately called a
Paddle Dyer.

Types of Dyed Garments
?Hosiery
?Pantyhose
?Sweaters
?T-Shirts

Methods of Dyeing
?Solution Dyeing
?Stock Dyeing
?Hank/Skein Dyeing
?Package Dyeing
?Beam Dyeing (Yarns)
?Winch/Beck Dyeing
?Jet Dyeing
?Jig Dyeing
?Pad Dyeing
?Beam Dyeing (Fabric)
?Paddle Dyeing

Solution (Dope) Dyeing
?As the name suggests, the dyestuff is
added to the chemical solution of the
man-made fiber. When the fiber filament
appears from the spinnerette, the
filament appears colored.
?The advantage of this technique is that
the colorfastness property of the textile
will be excellent.

Stock Dyeing
?The loose fibers are immersed in the dyebath before the processes of blending,
combing, carding, and spinning take place.
?The advantages of this technique are as follows:
?Excellent colorfastness property to the textile
?This allows creating a yarn of multiple colors to give a melange look in the
fabric.
?Uniform distribution of the dyestuff
?This is the costliest method of dyeing. The reason is that the dyeing is done
prior to manufacturing of the yarn, which will incur some wastage of the fibers,
depending on the quality of the yarn required for further processing.

Beam Dyeing (Yarns)
?In beam dyeing, the warp yarns are wound on cylindrical beams
which are placed in a machine.
?The dyebath is run in a center-to-outside and then in an outside-to-
center motion to get the desired depth of the color

Winch/Beck Dyeing
?The fabric ends are stitched together
to make a continuous piece.
?The fabric is then immersed in the dye
liquor in a slack condition and is rotated
by a roller in the dye liquor.
?The dye, in this case, is stationary
whereas the fabric moves.

Jig Dyeing / Jigger Dyeing
?This technique involves dyeing at the fabric
stage.
? In this technique, the fabric in an open-width
form is held up on two rollers in a machine
called a jig dyeing machine or a jigger.
?The fabric is unwound from one side,
immersed into the dyebath and then wound
onto the other side.
?The action is repeated until the desired color
is obtained on the fabric.

Jig Dyeing / Jigger Dyeing

Piece Jet Dyeing
?This technique involves dyeing at the
fabric stage.
?The fabric is placed in a rope-form in
a tube-like containment.
?There are pressure jets in the
container and the dye liquor is
penetrated through the fabric through
these jets.

Pad Dyeing
?This technique involves dyeing at the fabric stage.
?The fabric is wound on rollers in a pad dyeing
machine in an open-width form.
?The fabric in its long length is then made to pass
through a trough which contains the dye liquor,
and moved along the roller.
?It is a continuous process and the excess dye is
squeezed out of the fabric.

Beam Dyeing (Fabric)
?This technique involves dyeing at the fabric stage.
?Just like in the yarn stage dyeing method, the fabric is wound
on large cylindrical beams.
?The dye liquor is then pushed through the beams to impart
color to the fabric.

Technique for the Garment Stage
There is only one main dyeing technique that occurs during the garment stage.
?Paddle Dyeing

Paddle Dyeing
?This technique involves dyeing at the garment stage after the
construction of the garment.
?The garments are immersed in a dye solution placed in a large
container in the paddle dyeing machine.
?The garments are loosely packed and a motor driven paddle
circulates the dye solution in the container to impart color to the
garments.
?This technique can also be used for dyeing individual components
of a garment. In that case, the dyeing would take place before the
construction of the fabric.

Classification of Dyes
Dyestuffs can be classified by many methods as follows:
I. 1. by their ionic (e.g. cationic, anionic and non-ionic)
II. 2. by their fiber dye-abilities (e.g. on cellulosic, protein, polyester, polyamide
etc.)
III. 3. by their names (e.g. acid, direct, disperse, reactive, basic etc.)
IV. 4. by their chemical structures (e.g. azo, anthraquinone, stilbene etc.)
V. 5. by their origins (e.g. natural, synthetic)
VI. 6. by their colors (e.g. red, green, black etc.)

Classification based on Fiber dye-abilities

Classification based on Origin
A) Natural and
B)Synthetic dyes.

A). Natural Dyes
Natural dyes are taken from three sources namely plants,
animals and minerals.
?Vegetable Dyes : Around 4000 years back Egyptians
have used Indigo dyes, that are obtained from stems and
leaves of a particular plant.
?Alizarin dyes are taken from roots of madder plant.
?Logwood dyes are extracted from the trees which give
black colour to silk and cotton fabrics.

Indigo Dyeing Alizarin Dyeing

A). Natural Dyes
? Animal Dyes : Cochineal dye was extracted from an insect - Coccus Cacti.
The dye was taken after killing the female insects. These dyes were used for
imparting red and orange colours in silk and wool fabrics. Tyrian purple dye was
made out of shell fish.
?Mineral Dyes : Natural minerals yield certain varieties of dyes for example
Iron Buff.

Tyrian Purple

B). Synthetic Dyes
Synthetic dyes were first derived from coal tar in 1856.
Later innumerable dye compounds were made from coal tar, and are constantly
being improved as to beauty of colour and colourfastness. They are as follows :

Direct Dye or Salt Dye :
?Direct dye can be applied to animal fibre as well as vegetable fibre fabrics but
are generally applied to cotton and are known as Direct Cotton Dye.
?These dyes are soluble in water and are chiefly composed of amines and
phenols.
?Because a little salt is added to the solution while dyeing with direct dyes, these
are also called Salt Dyes.
?A further treatment with acetic acid and sodium dichromate is necessary to
make them fastness to washing.
?The dye colours often have only fair fastness to light, poor fastness to washing
and are not very bright.

Basic Dyes (Cationic Dyes)
?The first coal-tar dye was a so-called basic dye.
?Basic dyes are salts of organic colour bases.
?It was developed to give many bright shades of silk and wool.
?Basic dyes are known as cationic dyes, the same are used with a
mordant, Tannic acid, for cotton, linen, acetate, nylon, polyester and
acrylics.
?This dye gives beautiful colour but is not fast to sunlight, washing
and perspiration.

Acid (Anionic) Dyes
? Acid dyes are the sodium or calcium salts of colour organic acids.
?They are used mostly on wool and silk.
?Acid dyes are inexpensive and fairly fast to light, but they are not
fast to washing.
?Soap containing alkali if used will change the colour.

Mordant or Chrome Dyes : Sodium or Potassium dichromate
mordant is added in the dye bath. This mordant along with dyes will
penetrate into the fabric. These are used to dye wool and also for
printing cotton. These are fast to light, washing and perspiration.
Developed Dyes : This process requires a base to be dyed on the
goods. This is followed by a diazotizing process, whereby the dye is
chemically changed and treated with a fresh set of chemicals, called
developers, that form the completed dye. Developed dyes are fairly
fast to washing because they have been literally built into the fibre.

Sulphur Dyes : Sulphur dyes, first made in 1879, are used for cotton and linen.
Sulphur dyes are insoluble in water and must be made soluble with the aid of
caustic soda and sodium sulphide. These dyes are fast to washing, light and
perspiration, but excessive chlorine will strip the colour.
Vat Dyes : The first vat dye was an Indigo created in 1879. Vat dyes are the fastest
dyes for cotton, linen and rayon. Vat dyes are resistant to light, acids, alkali as well
as to oxidizing bleaches. Vat dyes are insoluble pigments, but are made soluble in
water by the use of a strong reducing agent, such as hydrosulphite developed in the
alkali sodium hydroxide. The fabric is immersed in this solution. Subsequent
exposure to air or immersion in an oxidizing bath (bichromate) restores the dye to
its insoluble form as a part of the fibre

Reactive Dyes : Reactive dyes were developed in 1957. These dyes react
with fibre molecules to form a chemical compound. These dyes were first
designed for cellulose fibres, now available for wool, silk, nylon, acrylics
and blends of these fibres. Advantages of reactive dyes are their excellent
fastness to light and washing. They give very deep and brilliant colours.
Pigment Dyes : Pigment dyes are not true dyes because they have no
affinity for the fibre and if applied and held to the fabric with resins, which
are then cured at high temperature. The colours, confined to light shades,
bright colours, such as metallic colours as gold are usually applied to cotton
cloth but are also used in fabrics of wool and manmade fibres.

Optical Brighteners (Colourless Dyes) : These so-called dyes are
also called fluorescent whiteners or optical brighteners. The
whiteness is really caused by absorption of ultraviolet light and
reflection of visible blue light. Optical brighteners are available for
cotton, acrylics, wool, acetate and nylon. They may be applied during
bleaching, before resin finishing or with the resin.

The End
Questionaries'

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Chap 2 Dyeing Process in textile fabric.

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Chap 2 Dyeing Process in textile fabric.