2.

1 FASHION FABRICS

Introduction to Textiles
Semester I, M.Voc Fashion Design
Module 2.1.2
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Weaves and Dyes

To make cloth by repeatedly crossing a single thread through two sets
of long threads on a loom is called Weaves. In weaving different weaves are used
to make different woven fabrics. To understand about different weaves, we need
to first understand the weaving process.

Weaving
It is the process of constructing woven fabric by interlacing warp yarns and weft
yarns on a machine called loom.

The weaving process consists of several phases, such as: winding, warping,
sizing, drawing-in, weaving and finally the control on the greige fabric.

1. Winding
Winding consists in winding the yarn on a tube. The weaving cones are prepared
for the warp (vertical threads) in a cylindrical form, all of the exact same length
to avoid waste. For the warp to be produced conical bobbins are made so that the
yarn can slide on the frame without problems. Sometimes the bobbins are wound
before dying in the form of a ball to allow that the dye colourant can penetrate
evenly throughout the yarn.
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2. Warping
This is the operation of the warp preparation. All vertical threads (warp) that will
compose the fabric (in some cases up to 16,000) are placed next to one another
to create the desired pattern. The warp cones are placed onto a frame called the
creel. The threads are then wound onto the reel, a large steel cylinder, to move to
the warp beam, a smaller cylinder that will be loaded onto the loom.

3. Sizing
Sizing serves to strengthen the fine single yarns for weaving. Yarns are
categorised into single and two-fold: the two-fold yarns are those composed of
two or more threads twisted together, while single yarns are very delicate and
difficult to weave. The warp threads are immersed in a bath containing the sizing
agent which stiffens them. The yarns, once released from the drying room, are
individually separated by large bars, not to create problems during weaving. Every
minute about 40 metres of warp is sized.
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4. Drawing In
In order to create fabrics with different structures (e.g., Oxford, poplin) each
thread has to move in a precise order, for this reason it is placed in the slats of
the warp stop, and drawn in thread by thread through the eyes of the heddle and
through the teeth of the reed. If a loom will weave successive fabrics with the
same structure, the drawing in stage can be skipped and tied each thread to the
corresponding warp thread that is ending directly in the loom. Thanks to modern
technology it is possible to draw in up to 200 threads per minute through the
heddles, reed, and comb in one pass. Despite the highly automated process it still
requires 2.5 hours of work to draw in an entire beam.

5. Weaving
When the weft yarn meets the warp, a fabric is created, synthesis of the raw
material and the creativity of the design and structure. The weaving is made on
highly technological weaving looms through a complex process carried out with
the utmost care, in a controlled environment, and with great experience of the
weaving staff. The looms can produce the simplest fabrics with 640 passes per
minute, but proceed much more slowly to weave the finest and most delicate
fabrics. The unfinished fabric at this stage is called greige.

Mechanism of Weaving

Primary Motions of Loom:

These are fundamental or essential mechanisms of loom. Without these
mechanisms, it is practically impossible to produce a fabric. It is for this reason
that these mechanisms are called ‘primary’ weaving loom mechanism.
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Fig: Weaving loom mechanism

The primary weaving loom mechanism are three in number:

1. Shedding mechanism
2. Picking mechanism
3. Beat-up mechanism

1. Shedding Mechanism
The shedding mechanism separates the warp threads into two layers or divisions
to form a tunnel known as ‘shed’. The shed provides room for passage of the
shuttle. A shed may be formed by means of tappets, dobby and jacquard.

Fig: Shedding mechanism

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Tappet shedding mechanism:

Generally there are two types of shedding

a. Negative tappet shedding

b. Positive tappet shedding

a. Negative Tappet Shedding:

In a tappet shedding mechanism, if the tappet controls only one movement, either
an upward or downward movement of the healed shafts, then the shedding is
known as “negative tappet shedding”. The healed shafts are returned by some
external devices like springs, dead weights, rollers, etc.

b. Positive Tappet Shedding:

In a tappet shedding mechanism, if the tappet controls both upward and

downward movements of the healed shafts, then the shedding is known as positive
tappet shedding.

Dobby shedding mechanism:

Dobby mechanism can control up to 30 healed frames. For cotton weaving, a

maximum of 24 healed frames can be used due to the staggering problem of
healed frames.

There are two types of dobby mechanisms, the negative dobby, and the positive
dobby, are mainly used. In negative dobby shedding, the dobby lifts the healed
frames, which are lowered by a spring motion. In positive dobby shedding, the
dobby raises and lowers the healed frames, and the springs are eliminated.

Jacquard shedding:

When a big or complicated design is to be made in weaving, jacquard

shedding is used. In this shedding, the warp ends are controlled individually by
harness cords, and there are no healed frames. There will be as many cords as
there are ends in the warp, which enables unlimited patterns to be woven.
Jacquard machines can be mechanical or electronic with single or double lift
mechanism.

2. Picking Mechanism

The process of propelling the weft yarn through the open shed by a weft insertion
element continuously across the width of the loom is called picking. It is the second
primary motion of loom, which is mainly classified according to the weft insertion
system. In early manual looms, weft yarn was inserted by an oblong-shaped
wooden element called a shuttle. Over pick or an under-pick mechanism is used
in conventional shuttle loom. But this picking system suffers many drawbacks such
as low speed, high power consumption, high noise level, and low-quality fabric. A
lot of researches have been conducted to avoid the use of shuttle in picking system
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to overcome this problem. The result of this is the innovation of air-jet, projectile,
rapier, water jet, multiphase weft insertion system, which are also called the
shuttle less loom. By using a picking mechanism, different types of yarns can be
selected one after another. For making delicate cotton fabric, the conventional
picking mechanism is still used with air-jet, rapier and projectile picking
mechanism.

Fig: Picking mechanism

The picking mechanism passes weft thread from one selvedge of the fabric to
the other through the shed by means of a shuttle, a projectile, a rapier, a
needle, an air-jet or a water-jet. The inserted weft thread is known as “pick”.

Classification of picking mechanism:

Picking mechanism can be classified in different ways. Classification of picking is
given below.

4. Beat-up Mechanism

Beating or the beat-up mechanism beats or pushes the newly inserted length of
weft thread (pick) into the already woven fabric at a point known as “fell of the
cloth”. The main objective of beat-up is to maintain the proper tension of the
overall fabric by letting the inserted weft yarn proceed forward with the progress
of the weaving cycle.
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Fig: Beating mechanism with sley

Beat-up includes several portions of the loom, including mainly race board and
sley. The lower portion of the warp yarns is in between the race board and the
shuttle. The reed and race board are assembled, and it is called a sley.

These three weaving loom mechanisms namely shedding, picking and then
beat-up are done in sequence.

Weaves
Weave in textile generally refers to the method, technique or the principle by
which the warp yarns and weft yarns interlace to construct a particular weave/
fabric on a machine called loom.

In the most basic of fabric weaving, the threads (lengthwise warps and crosswise
wefts) go criss-cross in the simplest pattern at right angles to each other. But in
others, they are woven in many exciting ways – artistically and decoratively. Do
you know that fabric factories can come up with a mind-boggling number of weave
structures?

But the basic weave types that mix and match to form all the others are:

1. Plain Weave
2. Twill Weave
3. Rib Weave
4. Satin/Sateen
5. Honeycomb Weave
6. Huck a Back Weave
7. Crepe Weave
8. Bedford Cord Weave
9. Welts and Pique
10.Mock Leno Weave
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Basic Weave Structure:

The fabric weave or design is the manner in which the warp and weft are
interlaced. The pattern or repeat is the smallest unit of the weave which when
repeated will produce the design required in the fabric. Weave is the interlacing
pattern warp and weft yarns, in order to produce a woven fabric. Weave structure
is the design by which fabric is produced.

Fabrics are manufactured in wide varieties and design. The great varieties of
weaves found in the textiles of today are modifications of a few fundamental
weaves invented in the earliest times. The basic weave structure is plain, twill,
and satin. All the others are derivatives of these basic weaves or their combination.
In this article I will discuss about different types of basic weave structure and their
names.

Fig-1:
Different types of fabric weave structure

All types of basic weave structure are described briefly.

Plain Weave:

In a plain weave, each warp yarn passes over alternate weft yarns. Neighbouring
warp yarns pass over the adjacent weft yarns. Plain is the simplest and commonly
used weave, in which warp and weft threads interlace in alternate manner (as
shown in Figure-2), giving maximum number of interlacements. This maximum
interlacement imparts firmness and stability to the structure. In trade, the special
names like broadcloth, taffeta, shantung, poplin, calico, tabby, and alpaca are
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applied to plain weave. At least two ends and two picks are required to weave its
basic unit. A minimum of two heald frames are required for this weave, but more
than two (multiple of basic weave) heald frames can be used to weave this
construction. In this type of weave, the warp and filling yarns cross alternately. It
is used in cambric, muslin, blanket, canvas, dhoti, saree, shirting, suiting, etc.

Figure-2: Plain weave structure

Plain weaves are basically three types. They are:

1. Warp Rib
2. Weft Rib
3. Matt Weave
4.

Warp rib:

Warp ribs are a modified form of plain weave. It has 1/1 interlacements in the
filling direction, which differs from the simple plain weaves. This modified
interlacement results in the formation of cords, ridges, or texture across the warp
direction of the fabric. These cords or ridges are formed due to the grouping of
the filling yarns. The repeat of warp rib is always on two warp yarns.

The first warp yarn follows the formula, while the second warp yarn is in the oppo-
site direction of the first one. It requires two healed frames at least, but multiple
of these can also be employed. The number of weft yarns in a repeat unit of this
weave is equal to the sum of the digits in formula of warp rib. For example, 2/2
warp rib requires 2 warp yarns and 4 weft yarns. Design of the above-stated warp
rib is shown in Figure-3. Warp rib is also known as ottoman.
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Figure-3: Warp rib (2/2).

Warp rib are two types:

1. Regular Warp Rib

2. Irregular Warp Rib

Weft rib:

Weft ribs are another modified form of plain weaves. It has 1/1 interlacements in
the warp direction, which differs from the simple plain weaves. This modified
interlacement results in the formation of cords, ridges, or texture across the weft
direction of the fabric. These cords or ridges are formed due to the grouping of
the warp yarns. The repeat of weft rib is always on two weft yarns.

The first weft yarn follows the formula, while the second weft yarn is in the
opposite direction of the first one. It requires two heald frames at least, but
multiple of these can also be employed. The number of warp yarns in a repeat unit
of this weave is equal to the sum of the digits in formula of warp rib. For example,
2/2 weft rib requires 2 weft yarns and 4 warp yarns. Design of the above-stated
warp rib is shown in Figure-4. Weft rib is also known as half Panama.

Figure-4: Weft rib (2/2).

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Weft ribs are two types:

1. Regular Weft Rib
2. Irregular Weft Rib

Matt weave:

This type of weave is constructed by extending the plain weave in warp and weft
directions at the same time so that two or more threads work alike in both
directions. In this weave, the same size of squares appears on both sides of the
fabric showing the same number of warp and weft yarns on front and back of the
fabric. Matt weave is also commercially known as basket, hopsack, or full panama.
This weave requires a minimum of two heald frames. Design of the 2/2 matt weave
is shown in Figure-5. The matt weaves can be extended further to give more
prominence but restricted due to lose structure and modified in several ways. In
matt weave, the warp ends that work alike tends to twist around each other. To
avoid this twisting of the yarns, warp ends that work alike are drawn from different
slits of the reed.

Figure-5: Matt weave (2/2).

Matt weave are three types:

1. Regular Matt Weave
2. Irregular Matt Weave
3. Fancy Matt Weave

Basket Weaves

Basket weaves are produced by combining warp and filling ribs. In basket weaves,
warp and filling yarns are grouped and they interlace together. Fig-6 shows a 2/2
basket weave. The number of warp and filling yarns in the unit cell is equal to the
sum of the digits in the formula. The basket weaves require a minimum of two
harnesses. Basket weaves can be classified as common formula or uncommon
formula. In a common formula basket weave, the first warp yarn and the first
filling yarn follow the same formula. In an uncommon formula basket weave, the
first warp and the first filling follow different formulae.
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Fig-6: 2/2 Basket weave

Other plain weaves:

1. Wicker weave
2. Chiffon
3. Georgette
4. Shantung
5. Seersucker
6. Regular basket weave
7. Irregular basket weave
8. Monks’ cloth
9. Oxford

Twill Weave:

Twill weave is another basic weave which is well known for its diagonal line
formation in the fabric due to its interlacing pattern. This weave and its derivatives
are used for the ornamental purposes. Twill has closer setting of yarns due to less
interlacement imparting greater weight and good drape as compared to the plain
weave. In simple twill, the outward and upward movement of the interlacing
pattern is always one that imparts a diagonal line to this design. The direction of
the propagation of twill line classifies twill into right-hand or left-hand twill. Twill
weaves are more closely woven, heavier and stronger than weaves of comparable
fiber and yarn size. They can be produced in fancy designs. Twill weaves find a
wide range of application such as drill cloth, khaki uniforms, denim cloth,
blankets, shirting’s, hangings and soft furnishings.
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Figure-7: Twill weave

There are various types of twill weave:

1. Zigzag weave
2. Warp faced twill
3. Weft faced twill
4. Balanced twill
5. Pointed Twill
6. Horizontal Pointed Twill
7. Vertical Pointed Twill
8. Herringbone Twill
9. Horizontal Herringbone Twill
10.Vertical Herringbone Twill
11.Skip Twill
12.Diamond Weave
13.Pointed Twill Base Diamond
14.Herringbone Twill Base Diamond
15.Combination Twill
16.Combined Twill
17.Broken Twill
18.Elongated Twill
19.Transposed Twill

Common derivatives of twill weave are described as follows:

▪ Zigzag weave – If the direction of the diagonal in a twill fabric is

reversed periodically across the width, a zigzag effect is produced.
Zigzag weave is achieved by simply combining two S and Z twill weaves
of equal repeat.
▪ Diamond weave – Diamond weaves are achieved by combining two
symmetrical zigzag weaves of equal repeat. Diamond designs are
vertically and horizontally symmetrical.
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▪ Herringbone weave – In Herringbone weave also the twill direction

is reversed periodically like zigzag weave but at the point of reversal
the order of interlacement is also reversed and then twill line
commence as usual.
▪ Diaper weave – Diaper weaves are produced when we combine two
Herringbone designs. Diaper designs are diagonally symmetrical.

Satin/Sateen:

Satin/sateen is a basic weave that does not have any regular pattern like twill.
The sateen weave is characterized by floating yarns used to produce a high
lustre on one side of a fabric. The surface of the fabric is either warp or weft faced.
The fabrics produced in satin weave are more lustrous as compared to
corresponding weaves. Satin is warp faced, which means that all the surface of
the fabric will show the warp threads except for the one thread interlacement with
other series of yarn. If it is weft faced, then it will be known as sateen, which
means that fabric surface will show the weft threads mostly.

The unique in this weave is the single interlacement of warp thread and weft
thread in a single repeating unit. These weaves have the least interlacement points
among the basic weaves. Due to this reason, it gives the surface of fabric more
lustre and smoothness. Along with these properties, more close packing of the
threads is possible, which gives the maximum achievable cover factor in this
weave. With this weave it is possible to use a cotton warp and silk filling, having
most of the silk appear on the surface of the fabric. Used for ribbons, trimmings,
dresses, linings, etc. and originally was an all-silk fabric with a fine rich glossy
surface formed in a warp satin weave.

Figure-8: Satin weave

Honey Comb Weave:

This name is given to this weave due to its honey bee web-like structure. It makes
ridges and hollow structures which finally give a cell-like appearance. In this
weave, both warp and weft threads move freely on both sides, which coupled with
rough structure. Name of weave used in towelling and occasionally for cotton or
wool suiting. The fabric made by this weave has longer float all over the fabric.
Due to this reason, it is radially absorbent of moisture. This property made these
weaves useful for towels, bed covers, and quilts. This weave is further divided into
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three types which are explained below. Most commonly, these weaves are
constructed on repeats which are multiple of four in ends and picks.

Figure-9: Honeycomb weave

Huck a Back Weave:

This weave is largely used for cotton towel and linen cloth. A heavy, serviceable
towelling made with slackly twisted filling yarns to aid absorption. It has longer
floated in two quadrants, which make them more moisture absorbent so employed
in towels. This weave is combination of longer floats of symmetric weaves in two
quadrants and plain weaves in the remaining two quadrants. Plain weave gives
firmness to the structure, while longer float weave increases the absorbency of
fabric, making it suitable for the above-stated purpose. Special draft is employed
for this weave. The draft is arranged in such a way that odd ends are drawn in two
front heald frames and the even threads are drawn from back two heald frames.
The purpose of this special draft is to weave plain fabric without redrawing of
beam. For this purpose, heald frame one and two are coupled together, and heald
frames three and four are coupled together. Sometimes, longer float symmetric
weaves are used in combination of plain weaves in huck a back weave, which is
also termed as honey comb huck a back weave. Examples of this weave are shown
in Figure-10.

Figure-10: Huck a back weave

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Waffle weave:
Waffle weaves are used for dishtowels. Waffle weave isn’t a separate structure in
its own, rather it’s all in the treadling.

Here is the draft of a typical waffle weave:

The threading here is the traditional point twill. Waffle weave is not only on point
twill threading’s, but also on Rose path and broken twill threading, as well as Huck,
Monk’s Belt, and Overshot. The tie-up involves tying two treadles for plain weave,
and tying the rest to lift (or sink) three shafts or one. This creates the floats, which
can be seen in the close-up view of fabric. The treadling is tromped as writ, which
simply means treadling in the same pattern as the threading draft, that means
treadling one through four and reverse. A combination of warp and weft floats
create the “waffles.”

Fig-11: Waffle weave

Crepe Weave:

Crepe weave refers to those weaves that do not have any specific pattern. These
weaves may contain a little bit appearance of twills, but they do not have the
prominence. They make small patterns or minute spots and seed-like appearance
all over the fabric surface. Crepe effect is brought by using hard twisted yarns or
by using the right- and left-hand twist of warp or filling yarns. These weaves may
be used separately or in combination with other weaves.

Crepe weaves are frequently employed in making the ground of the figured fabrics.
In simple words, crepe weave is used to make a rough appearance. If we make
crepe weaves with crepe yarns, this combination will give more remarkably pebbly
or puckered appearance. Uses of crepes are seen in kimonos, smocks, women’s
and children’s dresses, curtains, needlework. Crepe weaves can be drawn in
several ways, but the most common methods are given below.

• Sateen Method
• 1/4 Turn Method
• Reversing Method
• Super Imposed Method
• Plain Method
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Figure-12: Crepe (sateen based), 7 end.

Bedford Cord Weave:

This is a special class of weave that forms longitudinal warp lines in fabric with
fine sunken lines in between. This fabric is used in suiting for ornamental purposes.
The method to construct this weave is simple. The repeat of the weave is
calculated by multiplying the cord ends by two. The resultant value will be the
total number of ends of the weave repeat. The pick repeat is four for this weave.
The weave repeat (warp ends) is divided into two halves to construct it. The first
and last ends of both the halves are treated as cutting ends. Plain weave is
inserted on these cutting ends. These plain ends behave as sunken ends in the
Bedford cord.

Figure-13: Bedford cord weave, 10 threads cord with 2 waded ends

Welts and Pique:

A pique weave consists of plain face fabric which is composed of a series of warp
and weft threads along with a series of stitching threads. This weave is unique due
to the formation of horizontal lines (weft wise). This weave requires two beams,
one for the plain weave threads and the other for stitching ends. The word “welt”
is concerned to the pique construction, when the indentations make deep or hollow
(sunken) lines appear in the cloth.
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Figure-14: Welts and pique weave

Mock Leno Weave:

A leno weave is a locking type weave in which two or more warp yarns cross over
each other and interlace with one or more filling yarns. It is used primarily to
prevent shifting of yarns in open fabrics.

Mock leno weave is much similar to a gauze-type fabric. The weave is constructed
in four quadrants. The first and third quadrants have symmetric weave, and the
second and fourth quadrants have opposite weave to the symmetric weave. The
perforated fabrics are made by this type of weave. This effect is achieved by
reversing the symmetric unit of the weave in the alternate quadrants. So, these
weaves are produced in sections that oppose each other. The fabric appearance
can be improved or obscured by the system of denting that is employed in this
weave. The tendency of threads to run together is counteracted if the last end of
one group is passed through the same split as the first end of the next group.

The design of mock leno weave is shown in Figure-15.

Figure-15: Mock leno weave

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Dyes

A dye is a coloured compound, normally used in solution, which is capable of being

fixed to a fabric. The dye must be ‘fast’ or chemically stable so that the colour will
not wash with soap and water, fade on exposure to sunlight etc. Dyeing is
normally done in a special solution containing dyes and particular chemical
material. After dyeing, dye molecules have uncut chemical bond with fiber
molecules. The temperature and time controlling are two key factors in dyeing.
There are different types of dyes in market. This article will be helpful to identify
good types of dyes.

Fig: Different types of dyes

“It is defined as the compound which containing chromophore and auxochrome

groups called dye. Chromophore group is responsible for dye colour due to their
saturation. Auxochrome group is responsible for dye fibre reaction.”

Natural dye:

Natural dyes are simply dye substances extracted from natural sources. Although
the main source of dyes for early times, they have largely been replaced by
synthetic dyes, which are usually more reliable, cheaper and can be supplied more
readily. Natural dyes still in use include haematoxylin, carmine, orcein.

Colouring materials have been used for many thousands of years by man.
Leather, cloth, food, pottery and housing have all been modified in this way.
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Some of our most common dyes are still derived from natural sources. These are
termed natural dyes. The Colour Index uses this as a classification and naming
system.

Each dye is named according to the pattern:

Natural + base colour + number

Natural dyes are often negatively charged. Positively charged natural dyes do
exist, but are not common. In other words, the coloured part of the molecule is
usually the anion. Although the molecular charge is often shown on a specific atom
in structural formulae, it is the whole molecule that is charged. Many, but by no
means all, natural dyes require the use of a mordant.

Synthetic dye:
Dyes derived from organic or inorganic compound are known as synthetic dyes.
Examples of this class of dyes are Direct, Acid, Basic, Reactive dye, Mordant,
Metal complex, Vat, sulphur, Disperse dye etc. Synthetic dyes quickly replaced
the traditional natural dyes.
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They cost less, they offered a vast range of new colours, and they imparted
better properties to the dyed materials dyes are now classified according to how
they are used in the dyeing process.

Many types of dyes:

Acid dye:
Acid dyes are water-soluble anionic dyes, containing one or more sulfonic acid
substituents or other acidic groups. An example of the class is Acid Yellow 36.

Fig: Acid yello36

Acid dyes are water-soluble anionic dyes that are applied to fibers such as silk,
wool, nylon and modified acrylic fibers using neutral to acid dye baths. Acid dyes
are not substantive to cellulosic fibers. Most synthetic food colours fall in this
category. The dyeing process is reversible and may be described as follows:

Basic or Cationic Dye:

This group was the first of the synthetic dyes to be taken out of coal-tar
derivatives. As textile dyes, they have been largely replaced by later
developments. They are still used in discharge printing, and for preparing leather,
paper, wood, and straw. More recently they have been successfully used with some
readymade fibers, especially the acrylics. Basic dyes were originally used to colour
wool, silk, linen, hemp, etc., without the use of a mordant, or using agent. With a
mordant like tannic acid, they were used on cotton and rayon. Basic dyes give
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brilliant colours with exceptional fastness to acrylic fibers. They can be used on
basic dyeable variants of nylon and polyester.

Basic Brown 1 is an example of a cationic dye that is readily protonated under the
pH 2 to 5 conditions of dyeing.

Fig: Basic Brown 1

Direct Dye:

These are the dyes which can be applied directly to the fabrics from an aqueous
solution. These are most useful for fabrics which can form hydrogen bonds with
the Dyeing of Fabrics. The direct dyes mainly the basic dyes and were widely hailed
because they made it unnecessary to use a mordant or binder in dyeing cotton.
The colours are not as brilliant as those in the basic dyes but they have better
fastness to light and washing, and such fastness can be measurably improved by
after treatments (diazotized and developed.) Direct dyes can be used on cotton,
linen, rayon, wool, silk and nylon. These dyes usually have azo linkage –N=N- and
high molecular weight. They are water soluble because of sulfonic acid groups.

Direct orange 26 is a typical direct dye.

Fig: Direct orange 26

Azoic Dye:

Azo dyes contain at least one azo group (-N=N-) attached to one or often two
aromatic rings. These dyes are used primarily for bright red shades in dyeing and
printing since most other classes of fast dyes are lacking in good red dyes. Azoic
dyes, called Naphthol’s in the industry, are actually manufactured in the fabric by
applying one half of the dye. The other half is then put on and they combine to
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form the finished colour. Unless they are carefully applied and well washed, they
have poor fastness to rubbing or crocking.

The production of bluish red Azoic dye from the following two components is an
example.

Nitro Dye:
Nitro dyes are polynitro derivatives of phenols containing at least one nitro group
ortho or para to the hydroxyl group. It is used to dye wool. It Consist of two or
more aromatic rings (benzene, naphthalene).

Example:

Fig: Martius yellow

Disperse Dye:
Disperse dyes were originally developed for dyeing secondary cellulose acetate
fibers. These dyes are relatively insoluble in water and are prepared for dyeing
by being ground into relatively fine powder in the presence of dispersing agents.
In the dye bath, a suspension of the dye particle dispersion produces a very
dilute solution of the dyes, which are then absorbed by the fibers. This dye class
is used to dye polyester, nylon, acetate and triacetate fibers.

Disperse yellow 3, Disperse Red 4, and Disperse Blue 27 are good examples of
disperse dyes.
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Example:

Fig: Disperse Dye

Vat Dye:

The vat dyes are insoluble complex polycyclic molecules based on the quinone
structure (keto forms). The term vat comes from the old indigo method dyeing in
a vat: indigo had to be reduced to light form. Vat dyes are made from indigo,
anthraquinone and carbazole. They are successfully used on cotton, linen, rayon,
wool, silk, and sometimes nylon. Vat dyes are also used in the continuous piece
of dyeing process sometimes called the pigment application process. The dyeing’s
produced in this way have high wash and light fastness.

An example of a vat dye is Vat Blue 4 (Indanthrene).

Fig: Vat Blue 4

Mordant Dye:

These Dyeing of Fabrics do not dye the fabric directly but require a binding agent
known as mordant. The mordant acts as a binding agent between the fibre and
the dye. Some dyes combine with metal salts (mordanting) to form insoluble
coloured complexes (lakes). These materials are usually used for the dyeing of
cotton, wool or other protein fiber. The metallic precipitate is formed in the fiber
producing very fast colours highly resistant to both light and washing.
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Example:

Fig: Mordant Dye

Reactive Dye:

These dyes react with the cellulosic fiber to form a covalent bond. This produces
dyed fiber with extremely high wash fastness properties. These are the dyeing
of fabrics which contain a reactive group which combines directly with the hydroxyl
or the amino group of the fibre. Because of the chemical reaction the colour is fast
and has a very long life. Cotton, wool or silk can be dyed with this type of dyeing
of Fabrics. There are various types of reactive dyes used in dyeing industry.

Example: This type is the Reactive Blue 5 dye shown below,

Fig:
Reactive Blue 5

Solvent Dye:

These dyes are water-insoluble but soluble in alcohols, chlorinated hydrocarbons,

or liquid ammonia. These colours are applied by dissolving in the target, which is
invariably a lipid or non-polar solvent. The Colour Index uses this as a classification
and naming system. Each dye is named according to the pattern: – solvent + base
colour + number They are used for colouring synthetics, plastics, gasoline, oils
and waxes.
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Example:

Fig: Solvent yellow32

Sulphur Dye:

The Sulphur dyes provide very deep shades, which have excellent resistance to
washing but poor resistance to sunlight. They will dye cotton, linen, and rayon,
but not brightly. A problem with sulphur dyes especially the black colours is that
they make the fabric tender, or weaken its structure, so that it breaks easily.
Sulphur dyes are applied to cotton from an alkaline reducing bath with sodium
sulphide as the reducing agent. They are low cost and have good fastness to
light, washings and acids.

Example:

Fig: Sulphur red 7

Properties of dyes:

• These dyes are economical dyes and are generally used to produce dark
shades such as dark greens, dark blues and blacks.
• These dyes have good levelling and colour fastness properties.
• The interaction between fiber and dye is established through very
strong ionic bonds, which are formed between the anionic groups of the
colorant and ammonium cations on the fiber. Chromium or the metal
ion acts as bridge between the dye and fiber, which gives rise to a very
strong linkage, resulting into excellent fastness properties.
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Some dye application:

Name of Dyes Application

Acid dye Man made fiber (Nylon), Natural fiber (Silk, Wool)

Direct Dye Manmade fiber (Viscose), Natural fiber (Cotton)

Man made fiber (Viscose), Natural fiber (Cotton,

Vat dye
Silk, Wool)

Disperse dye Nylon, Polyester, Acrylic, Tri-acetate, Di-acetate

Basic dye Jute, Acrylic

Reactive dye Cotton, Wool, Silk, Viscose, Nylon

Sulphur dye Cotton, Viscose

Mordant dye Cotton, Wool, Silk

Pigment Cotton, Man made fiber

Mineral Cotton, Wool, Silk

Azoic dye Cotton, Viscose

Aniline Black Cotton

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Rapid and Rapidson dye Cotton

Onium dye Cotton, Jute

Dye is very important for textile sector. Because the fabric is to make attractive
to us by dyeing. Dyes that are used by the Textile industry are now mostly
synthetic. These types of dyes are marketed power granules and liquid dispersion.
Now the industrial Textile dyes must rise up to meet all these new and specific
technical requirements.