Textile studies and its different aspects For reference purpose of students of design schools worldwide

1. TEXTILE STUDIES
By Rajesh Sharma, India

2. BLENDED FABRICS
 The variety of natural and manmade fabrics available today, offers a wide
selection of fibres for use. But all fabrics are not perfect in one way or
other. They all have some good, fair and poor charcteristics.
 Man's desire, to produce perfect fabrics resulted in the production of
blended fabrics.
 Blended fabrics are created when two or more different kinds of fibres are
mixed together to create a new fabric with unique properties.
 Blending of cellulosic fibres with manmade fibres to produce fabrics with
improved
 characteristics has long been accepted throughout the world. The uses of
blended fabrics have been tremendously increased even in India.

3.  The price structure and multi fibre policy of government have increased the
use of cellulosic blended fabrics.
 The properties of the fibres blended are combined and made into a
modified state in blended fabric.
 If blending is done carefully the good qualities of the fibres are
emphasized minimising the poor qualities.

4. Reasons why fabrics are blended
 1. The important reason for blending fibres is to produce better
performance. By blending we can improve the characteristics that are poor
in one fibre, by blending it with another type of fabrics that excel in those
characteristics
 For example polyester when blended with cotton, the resultant fabric has
moderate absorbancy which is almost nil in polyester.
 2. To improve the texture, hand or feel and appearance of fabrics blending
of wool fibres with polyester produces the desired texture for suiting
materials. Viscose when blended with cotton improves it's lusture and
softness and there by enhances it's appearance.

5.  3. To reduce the cost- This is sometimes one of the important reasons for
blending of fibres. The cost of a very expensive fabric can often be
reduced by blending with another cheap fibre. For example expensive
wool is blended with cheaper polyester to reduce the cost.
 4. To produce cross dyed effects- Fibres with unlike dye affinity are
combined and dyed together so that it produce interesting cross dyes
effects as one fibres take up the colour and the other retains its original
colour.
 5. To improve the spinning, weaving and finishing efficiency for example the
spinning efficiency of polyester is improved by blending with cotton to
produce spun yarns.

6.  Blending may be done before or during spinning. It can be done at the
opening and blending stage. though it facilitates perfect blending it poses
problems and so it is not in much use.
 Even at the sliver stage over drawing or roving or spinning frames blending
can be done.
 Blending over drawing frame is most commonly used today.
 slivers of different fibres are combined over drawing frame depending on
blend ratio.
 They are drawn to get a single silver which is later processed into yarn.

7. TYPES OF BLENDED FABRICS
 Among the various tyes of blends available today, the most popular fabrics
are terry cotton, terry wool, polyester viscose. Polyester cotton viscose
blends are most common.
 Various effects and combinations of properties are produced from these
blends depending on the fibres used and the percentage of these fibres
used in each blend.
 1 Terry Cotton- Fabrics of various blend ratios are available in the market
today. A blend of 65% polyster and 35% cotton is common. The other
blend ratios are 67/33, 70/30, 50/50, 45/55, 52/48, 80/20 polyester
and cotton respectively are also available.
 A blend of 65/35 polyester and cotton produces satisfactorily a fabric for
daily wear. 59/50 blend produces more softer and more absorbent fabric.

8.  Polyester when blended with cotton contributes more strength wrinkle
resistance and shape; retention, cotton produces comfort as it provides
absorbency and heat conduction. The polyester cotton
 blend is most suited for not only India but also for other tropical countries.
 2 Terry-wool Suiting Fabrics- The excellent shape retention of polyster is
the foremost contribution to worsted fabrics which show poor shape
retention.
 Polyester provides excellent wrinkle resistance and crease retention that
contributes to shape retention whether wet or dry.
 Depending on the blend ration polyester increases the strength of wool
fabrics. Wool provides warmth resiliency, drapability and absorbency
depending on the blend ratio.

9.  Blends of polyester and wool are available in ranges from 65% polyster
and 35% wool to 60/50, 55/45, 5/50 respectively.
 A blend of 65/35 will be suitable to produce a light weight, all season
suiting. For medium worsteds 60/40 blend is suitable. When more warmth is
required 50/50 blends should be opted.

10.  3 Polyster Viscose Rayon- The blend of polyester with viscose contributes
durability, resiliency and shape retention. The wet strength of the resultant
fabric is also improved, viscose provides absorbency, soft texture and
variety of colour.
 Blend of polyester and viscose generally ranges from 65% of polyester
and 35% viscose to 55/45, 45/55, 48/52 respectively. Among these
blend levels 48/52 and 65/35 are commonly used for school uniforms and
suiting materials.
 4 Elastane (spandex) and cotton- A natural mix for sport clothing as
elastane is stretchy and durable while cotton lets your skin breathe and
controls odours. Also good for skinny jeans.

11. FINISHING: TYPES OF FINISHES
 A finish is anything given to fibre, yarn or fabric to improve hand,
appearance or performance.
 A finish is defined as anything that is done to fibre, yarn, or fabric either
 before or after weaving or knitting to change the appearance, the hand,
and the performance.
 A finish may consist of an application of a wide variety of treatment and
 special processes that given to fibre, yarn or fabric to enhance their
aesthetic or performance properties.

12.  Certain finishes are so temporary that they completely lose their
effectiveness after one laundering.
 Therefore, understanding textile finishes and the properties they impart,
 the fibers and fabrics, to which they may be applied, and their limitations
and shortcomings are important to an overall understanding of textiles.
.

13. FINISHING
 Finishing is the general term for a multitude of processes and treatments
which a fabric may undergo after it has been made (woven or knitted) and
coloured (dyed or printed).
 It is the final processing of the cloth and its purpose is to make the fabric
suitable for its intended end use. That may mean for example, making the
fabric shrinkproof, softer, stiffer, water repellent, crease resistant or a
combination of these properties

14.  Advantages of Finishes:
 Improves appearance- luster, whiteness etc.
 Improves feel (which depends on the handle of fabric and its softness
etc.)
 Improves wear (anti wrinkle, soil release)
 Gives special properties required for particular uses (water proof, flame
retardant)
 Increase the weight of fabric
 Increase market value
 Improves aesthetic value of fabric
 Improves serviceability of the fabric

15. CLASSIFICATION OF FINISHES
 Textile finishes and finishing are classified in several ways.
 1. On the basis of their degree of permanence
 Permanent finishes usually involve a chemical change in fibre structure and
will not change or alter throughout the life of a fabric.
 Durable finishes usually last throughout the life of the article, but
effectiveness becomes diminished after each cleaning, and near the end of
the normal use life of the article, the finish is nearly removed.
 They lasts longer than a temporary finish.
 Semi-durable finishes last through several launderings or dry cleanings and
many are renewable in home laundering or dry cleaning.
 Temporary finishes get removed after a few washes. It lasts until the
garment is washed or dry-cleaned.

16.  Renewable finish can be applied by the homemaker with no special
equipment, or it may be applied by the drycleaner.
 A single fabric can be given several finishes that are each intended to
accomplish
 different purposes. For example, a fabric may be bleached to enhance
whiteness, and
 then given a permanent press finish to make it resist wrinkling.

17.  2. On the basis of mode of action
 Persons concerned with textile processing (chemists and finishers) categorize
finishes into chemical finishes and mechanical finishes.
 These are also called wet finishing and dry finishing, respectively.
 Mechanical finishes that cause a physical change only.
 Examples of mechanical finishes are calendaring, raising etc.
 Chemical finishes in which a chemical reaction causes a permanent change
in fibre.
 Examples of chemical finishes are water proof, flame retardant etc.

18.  3. On the basis of achieved results
 This is the most common classification method which is based on achieved
results.
 here are two categories of finishes, viz., basic/routine/general finishes and
special or functional finishes. Routine finishes are applied to almost all
fabrics with an aim to improve their appearance.
 Routine finishes are often used to process natural fibers, notably cotton and
wool (cleaning, scouring, singeing) to remove dirt and matter involved in
growth and initial processing.
 Special/functional finishes are applied with a specific purpose or end use in
mind.

19.  BASIC/ROUTINE FINISHES
 In the processing of natural fibers, impurities such as grease and vegetable
matter in wool, gum in silk, or vegetable matter in cotton have been
removed.
 Some of the residue of these substances may remain even after spinning
and weaving. Also, fabrics may become soiled during weaving. Temporary
starches (called sizing) may have been
 applied. These substances must be removed before further treatment is
given to the fabrics.
 Hence, these finishes are also referred to as preparatory finishes. Not all
fabrics undergo each of these processes. The final list is decided by the
finisher on the basis of the market requirement.

20.  i) Desizing- Warp yarn contain ingredient applied to them before weaving,
during the process of sizing. In order to protect the warp yarns (before
weaving) against injury from harness wear in the loom, it is necessary to lay
the fibres extending along the surface of the yarn by coating them with a
thin layer of starch before winding them upon the beam of
 the loom. This is done by immersing the yarns continuously for a few seconds
in a hot mixture containing an adhesive, such as starch, a lubricant such as
softening oils (vegetable oils) and a preservative.

21.  It is necessary to remove the size from the cloth, otherwise the
hydrophobicity of the starch and other materials applied during sizing
process will hinder the subsequent dyeing and printing processes. Wax and
tallow are removed in the process of scouring while the starch is removed
during desizing. Thus desizing is the term usually restricted to the process of
removal of starch of the size from the cloth.

23.  ii) Scouring- After desizing the cloth contains oils, fats, waxes and colouring
matters.
 These compounds affect the absorbency of the cloth. This leads to improper
dyeing, printing and finishing in the subsequent processes. These materials
present in fabric affects the penetration of the dye on to the fabrics. These
impurities are removed from the fabric by the process called as scouring
process.
 The main purpose of scouring cotton fabric is to remove natural as well as
added impurities of essentially hydrophobic character as completely as
possible and leave the fabric in a highly absorptive condition without
undergoing chemical or physical damage significantly and also to make the
goods suitable for removing the natural colouring matter of the cotton
during the subsequent bleaching process.

24.  Scouring process consists in circulating hot alkaline liquors, usually under
pressure through a regularly packed of column of desized fabric for 8-24
hours with temperature of 1200-1300 C.
 The scouring process is also known as kiering, kier boiling, boiling out etc.
Scouring is carried out in a boiler in which yarn or cloth is boiled with
alkaline liquors. The boiler is called a kier and hence the terms kiering and
kier boiling are also used for scouring.
 The scouring of wool is done in solutions of less concentration and at lower
temperatures than scouring of other fibres because most scouring solutions
are alkaline in nature and wool is damaged by alkal

25.  iii) Carbonizing of Wool- Carbonizing is a chemical treatment of wool with
strong acid designed to remove any remaining vegetable impurity. This
process removes leaf particles and bits of grass and other cellulosic
impurities that become embedded in the wool while
 sheep are grazing. Carbonizing is accomplished by the immersion of wool
in sulfuric acid.
 Because strong acids readily attack the cellulose of the vegetable matter
and do not immediately harm protein fibers like wool, the burrs, sticks,
leaves, and the like that remain in the wool are destroyed. Carbonizing is
normally carried out either at the loose wool
 stage or on the fabric.

26.  The action of the acid is to hydrolyse the vegetable matter to a dark, brittle
hydrocellulose which can be removed mechanically by crushing it between
rollers and then dusting the debris out of the wool in a rotating cage.. As a
final step in carbonising process, the goods must be neutralized and rinsed.
Wool fabric or fibre is placed in a beaker filled with warm slightly alkaline
soap liquor. Ammonia is preferred because it does not damage the wool so
much.
 The treatment is carried out under carefully controlled conditions so that the
wool is not damaged, and the fabric is given a careful scouring afterward
to remove or neutralise all of the acid that remains.

27.  iv) Degumming of silk- Silk fibres contain sericin gum from
 20-30% on weight of material. Gum obstructs the penetration
 of dyestuff into the fibre and also affects the luster. So the
 process of elimination of gum becomes essential and this
 process is known as degumming.
 Silk boiling off is usually carried out with alkaline reagents, considering that
sericin is particularly easy to dissolve in an alkali medium. Soap is a good
degumming agent and gray fabrics can be completely freed from sericin
by treating them for 1-2 hours in 1% solution of soap (10-15 g/l

29.  v) Fulling/Milling- Fulling is a permanent finish used on wool fabrics; it is
also known as milling or felting. Wool fabrics are fulled in order to give the
fabric a more compact structure. In a type of preshrinking, fabrics are
subjected to moisture, heat, soap, and pressure. This causes the yarns to
shrink and to lie closer together, and give the fabric a
 denser structure. Wool cloth may be given more or less fulling, depending
upon the desired characteristics of the resultant fabrics. Melton cloth, for
example, is one of the most heavily fulled wool fabrics, and has a dense,
feltlike texture.

30.  vi) Singeing- Singeing is the burning of free projecting fibre ends from the
surface of the cloth. These protruding ends cause roughness, dullness, pilling,
and interfere with finishing. To produce a smooth surface finish on fabrics
made from staple fibers, fabrics are passes over a heated copper plate or
above a gas flame. The fiber ends burn off. The fabric is moved very
rapidly and only the fibre ends are destroyed. Immediately after
 passing the flame, the fabric is passed through a water bath to put any
sparks that might remain.

31.  Singeing is the first finishing operation for all smooth– finished cotton fabrics
and for clear-finished wool fabrics.
 Fabrics containing heat-sensitive fibers such as polyester/cotton blends are
often singed after dyeing or printing because the little melted balls on the
ends of the fibers interfere with dye absorption that may cause unevenness
in the colour.
 Filament yarns do not require singing, as there are no short fibres ends to
project onto the surface of the fabric. Singeing is one of the best remedies
for the problem of pilling that occur in some man-made fibres.
 Improper singeing or elimination of this operation results in unclear print
patterns, mottled (spotty) fabric surface, or premature pilling of fabrics.

32.  vii) Stiffening- Typical fabrics that have stiffening finishes are buckram,
crinoline, lawn and voile. Some fabrics need to be made stiffer and crisper
than they would otherwise be in order to properly fulfill an intended end
use.
 Sizing- In order to add body to fabrics, some type of sizing is often
applied. This may be in the form of starch, gelatin, resin, or a combination
of these with softening substances such as oils or waxes.
 Starch and gelatin are temporary sizing and are removed during
laundering or dry cleaning.
 In addition to making fabric stiffer, the starch also adds body
 and weight to the fabric, and sometimes misleads consumers into believing
they are purchasing better fabrics when, in fact, the fabrics may be poorly
made.

33.  Inexpensive cotton or rayon fabrics are often heavily starched, and after
laundering may become quite limp. Gelatins are used as sizing on rayons
because they are clear in colour and do not dim the luster of the fabric.
Various resins can also be used to add body to fabrics.
 These resins produce a durable finish. The resin attaches to the surface of
the fibre or actually impregnates the fibre.

34.  Permanently Stiffened Cottons: By a special acid treatment known as
parchmentizing, some cottons are given a permanently stiff character. The
application of a carefully controlled acid solution causes the surface of the
yarn to become softened and gelatin like.
 An afterwash in cold water causes the gelatinous outer surface to harden,
forming a permanently stiffened exterior. Permanently finished organdy is
one of the fabrics that are made by this process.

35.  viii) Weighting of Silk- In weighting process silk is treated to restore or
increase the weight lost during the process of degumming. Raw silk contains
from 25 to 30 per cent of its weight in sericin or gum. When the fibre is
cleaned, this substance is removed.
 Silks may be weighted both to enable the producer to regain some of the
loss in fibre weight and to add greater body to fabrics.
 The silk fabric is first placed in an acid solution of stannic chloride (a
chloride of tin). The fibre absorbs the substance, then is washed, placed into
a solution of sodium phosphate, and then washed again.

36.  During this process, an insoluble compound (tin phosphate) is formed within
the fibre, and the weight and body of the fibre is increased.
 A further treatment with sodium silicate solution forms another chemical
compound and still greater weight. These steps can be repeated a number
of times, and with each repetition, greater weighting is achieved.
 While silk is a strong and durable fibre, the weighting process is highly
damaging to the finished goods. If the garment is worn, it wears out quickly
and is highly susceptible to perspiration, salt, and tears; if stored away it
 becomes brittle and breaks.

37.  ix) Decatizing- Decatizing is a mechanical finish involving heat and
pressure. Decatizing produces a smooth, wrinkle-free finish and lofty hand
on woollen fabrics and on silk, blends of wool and man-made fibers. A high
degree of luster can be developed by the decatizing process because of
the smoothness of the surface.
 The dry cloth is wound under tension on a perforated cylinder. Steam is
forced through the fabric. The fabric is steamed for up to ten minutes and
then cooled down. The piece is then reversed and steamed again in order
to ensure that an even treatment is achieved. The moisture and heat cause
the wool to become tensions relax and wrinkles are removed. The yarns
become set in the shape of the weave and are fixed in this position by the
cooling-off, which is done with cold air

38.  x) Bleaching- The removal of wax, natural fats and added fatty matter
(from the size) and other impurities from the desized fabric during the
scouring process carried out in a kier leaves the material in a more
absorbent condition than the gray fabric.
 But the natural colouring matter present in cotton is still present in the cloth.
In order to obtain white cloth, the normal practice is to decolouries the
natural colouring matter present in the cloth thus a final bleaching process is
essential for obtaining a good white and this is done by bleaching in
different ways.

39.  Fabrics are bleached or whitened in order to prepare them for dyeing or
printing or in order to produce a fabric that is of a clear white colour. Most
bleaches are oxidizing agents.
 The actual bleaching is done by active oxygen. A few bleaches are
reducing agents. Bleaches may be either acid or alkaline in nature.
Bleaches are usually unstable, especially in the presence of moisture.
Bleaches that are old or not stored properly will loose their bleaching
power. Any bleach will cause some damage and since damage occurs more

40.  rapidly at higher temperature and concentration, these factors should be
carefully controlled.
 The same bleach is not suitable for all kinds of fibres. Because fibre varies
in their chemical reaction, bleaches must be chosen with regard to fibre
content.
 The bleaching step is often omitted with wool because it has good affinity
for dyes and other finishes even if not bleached.

41.  Liquid chlorine bleaches were for many years, the common household
bleaches. They are cheap and efficient bleaches for cotton and rayon.
 Peroxide bleaches are common factory bleaches for cellulose and protein
fibres and fabrics.
 Sodium perborate is a powder bleach which becomes hydrogen peroxide
when it combines with water. It is safe bleach for home use with all kinds of
fibres.
 Acid bleaches such as oxalic acid and potassium permanganate have
limited use. Citric acid and lemon juice are also acid bleaches, which are
good rust spot removers.
 Reducing bleaches such as white Rit will whiten nylon and strip colour from
some dyed fabrics.

42.  xi) Florescent Whiteners- In addition to bleaching, many white fabrics are
treated with fluorescent whiteners (also known as optical brighteners) to
enhance their whiteness.
 Fluorescent whiteners are not bleaches, but are dyelike compounds that
emit a strong bluish fluorescence. These substances have the capability of
absorbing ultraviolet light and emitting visible blue fluorescent light. This
causes the white to appear whiter and brighter.
 Optical brighteners are reasonably fast to laundering. They are present in
many detergents and can also be purchased for use in home laundering.
 They are also added to the spinning solution of some manmade fibres to
optically brighten them.

43.  xii) Delustering- Many of the man-made fibers have a high natural luster
or brightness. Some man-made fibers are treated to reduce this
 luster before the fibre is formed.
 Pigments such as titanium dioxide are added to the solution before the
fibre is extruded.
 The tiny specks of pigment cause the fibre to reflect less light, and thereby
decrease the brightness. Surface and cross sections of delustered fibres
show a number of small, dark flecks or spot in a random distribution.

44.  Cross section view of cellulose triacetate showing
Cross section before and after delustering

45.  xiii) Mercerization- Mercerization is the action of an alkali (caustic soda)
on a fabric.
 Mercerization is used on cotton and linen for many reasons. It increases the
luster and softness, give greater strength, and improves the affinity for dyes
and water-borne finishes. “Mercerized cotton” on a label is associated with
luster.
 Cotton is mercerized for luster in both yarn and fabric form. Most good
quality cotton sewing threads are mercerized to improve their strength.
Mercerization is a permanent finish, and it is one of the few finishes applied
prior to dyeing.

46.  Yarn mercerization is a continuous process in which the yarn under tension
 passes from a warp beam through a series of boxes with guide rolls and
squeeze rolls, through a boil-out wash, and a final wash. In case of fabric
mercerization, the cotton fabric is immersed under tension in
 a strong solution of sodium hydroxide for a short controlled period of time
(usually four minutes or less).
 The alkali is washed of and any excess alkali is neutralized.

48.  Changes during mercerizing process
 Fiber level
 1. Swelling
 2.Cross sectional morphology changes from bean shape to round
 shape.
 3. Shrinkage along with longitudinal direction.
 Molecular level
 1. Hydrogen bond readjustment
 2. Orientation (parallelization) of molecular chains in amorphous region
along the direction of fiber length.
 3. Increased crystallinity

50.  Greater absorbency results from mercerization because the caustic soda
causes a rearrangement of the molecules, thus making the hydroxyl groups
available to absorb more water and waterborne substances.
 Thus dyes can enter the fibre more readily, and when they can be fixed
inside the fibre more readily, and when they can be fixed inside the
 fibre, they are faster.
 Mercerized cotton fibres are stronger because in the swollen fibre,
 the molecules are more nearly parallel to the fibre axis. When stress is
applied, the attraction, which is end-to- end molecular attraction, is harder
to rupture than in the more spiral fibril arrangement.

51.  Slack mercerization, or mercerization of fabrics that are not
held under tension, is used
 to produce stretch fabrics. During slack mercerization, yarns shrink and
develop a good
 degree of elasticity. The finished fabric can be stretched, and when the
tension is removed the goods will return to their original length.

52.  xiv) Simple Calendering- Calendering is a process of pressing or ironing a
fabric at high speed and under high pressure.
 Calendering is a broad general term that refers to a mechanically
produced finish achieved by passing fabrics between a series of two or
more rollers. The object of calendering is to smooth the fabric.

54.  xv) Beetling- Beetling is a mechanical finish applied to cotton and linen
fabrics. They are beetled, by pounding the fabric (in a machine equipped
with hammers that strike over the surface of the fabric) to flatten the yarns
and make them smoother and more lustrous.
 Yarn flattening provide more area for light reflection. The fabric is fed over
rolls that rotate slowly in a machine where large hammers rise and fall on
the fabric surface. Continued pounding for a period of 30 to 60 hours
flatten the yarns and closes the weave.
 Unless a resin treatment has been given to the fabric before beetling this
must be considered a temporary finish

55.  xvi) Tentering- Tentering, one of the final finishing operations, performs the
double process of straightening and drying fabrics. In the application of
many finishes, the fabric must be immersed in a liquid.
 To dry the fabric without wrinkles, fabrics are stretched
 between two parallel chains of correct width. The fabric is held in place on
the tenter frame by pins and clips. Examination of the selvedge of fabrics
will usually reveal either small pin holes or marks from the clips.
 The tenter frame carries the fabric into a drying apparatus where the
fabric is dried under tension and made wrinkle free.
 Fabrics that have not been set on the tenter frame will be off-grain. Some
fabrics that are off grain can be straightened by pulling the yarns into the
correct or straight position.
 However fabrics that have had heat setting or resin treatments cannot be
straightened and will always be off-grain. The serviceability and aesthetic
qualities of fabrics are therefore, adversely affected by poor tentering.

56.  Fabrics that have not been set on the tenter frame will be off-grain. Some
fabrics that are off grain can be straightened by pulling the yarns into the
correct or straight position.
 However fabrics that have had heat setting or resin treatments cannot be
straightened and will always be off-grain. The serviceability and aesthetic
qualities of fabrics are therefore, adversely affected by poor tentering.

57. Tenter Dryer

58.  xvii) Loop drying- Fabrics with a soft finish, towels and stretchy fabrics
such as knits are not dried on the tenter frame but are dried on a loop
dryer, where the drying can be done without tension.

59.  SPECIAL/FUNCTIONAL FINISHES
 These finishes are aimed at aesthetic and/or performance. These can be
further divided into four categories, describe below:
 i) Finishes that alter appearance by mechanical means:
 a) Napping/Raising- Nap consists of a layer of fibre ends on the surface
of the cloth that are raised from the ground weave by a mechanical
brushing action. Napping was originally a hand operation,
 in which the napper tied together several teasels (a dried flower) with
many fine, hook like, sharp projections and swept them across the surface of
the cloth to raise fibres from the ground weave.

61.  The raised fibres formed a nap that completely changed the appearance
and texture. Some very fine napped wools are still made by using natural
teasels. Most napping is now done by rollers covered by a heavy fabric in
which bent wires are embeded.
 Napping machine may be single action or double action. Few rollers are
used in the single action machine. They are all alike and travel at the same
speed.
 They are called pile rolls and the bent end of the wires point in the
direction in which the cloth travels but the rollers rotate in the opposite
direction. These rollers are all mounted on a large drum or cylinder which
 rotates in the same direction as the cloth. In

63.  the double action napping machine every other roll is a counter pile roll.
This roll has wires which point in the direction opposite to those of the pile
roll. The counter pile roll must travel slower than the cloth in order to
produce a nap.
 Flannel is so far the most common and widely used napped fabric. It can be
woollen flannel, worsted flannel and cotton flannel or even rayon flannel.
Blanket is another example of napped fabric used primarily for warmth..

65. b) Sueding- It‟s a finish similar to napping, is a mechanical finish that
produces soft, suede like surface on the fabric. Instead of the rotating cylinders
used for sueding consist of sandpaper like material.
c) Flocking- A surface effect that is similar to a nap or pile may be created by
flocking, in which short fibres are glued onto the surface of fabrics by an
adhesive material. If the adhesive coats the entire surface of the fabric,
the flocking will cover the entire surface of the fabric, but if the adhesive is
printed onto the fabric in a pattern of some sort, the flock will adhere only in
the printed areas. The short fibres are identified as flock. For a surface
that is to resemble a pile, the flock is left erect on the fabric surface, while for a
fabric that is more like a napped surface the flock is pressed somewhat.

67.  The fibres used for the flock are generally of either rayon or nylon. These
fibres are cut so that the ends are square and even. The length may vary,
but the average is about 1/8”.
 Rayon is used most often because of low cost and nylon is selected where
good abrasion resistance is required. Fibres for flocking are made from
bundles of tow fibre (continuous filament fibres without twist). The tow is fed
through a finish removal bath and then into a bank of cutter that cut flock
of the desired length.
 The fibres may be dyed before they are attached to the fabric, or the
completed fabric may be dyed.

68.  The adhesive is printed on the fabric and the attachment of the flock to the
fabric is done by either of two methods, mechanical method and
electrostatic method.
 The vibration or mechanical method can apply flock to one or both sides of
the fabric.
 The flock is sifted through a container known as flock hopper on the fabric
surface. A series of beaters agitate the fabric causing most of the fabric to
be set in an upright position. As the fabric moves it vibrates.
 One end of the flock adheres to the areas where the adhesive has been
applied. The fabric then moves into a drying chamber, where the adhesive
dries with the flock firmly embedded.
 Finally the fabric is brushed to remove flock from areas where there is no
adhesive.

70.  The second method, the electrostatic or electro coating technique depends
on the electric charge of the fibres. The fabric printed with the adhesive,
passes over an electrical field, which establishes an atmosphere that forces
the loose fibres in the area away from

71.  e) Special calendaring- Just like simple calendaring, this is a mechanical
finish imparted with the aid of rollers. What is different is that that a design
is introduced in the fabric. It is temporary when applied to cotton but can
be made permanent by treating cotton with resins or use of thermoplastic
fabrics.
 Embossed Calendering- Embossed calendaring produces a three-
dimensional design on the fabric. Embossed designs are produced by
pressing a pattern onto fabrics like other calendered finishes, they may be
permanent when applied to thermoplastic fibres, durable when applied to
fabrics that have been resin treated and temporary on other fabrics.
 Nylon, acrylic, acetates, polyesters and fabrics made of nylon and metallic
yarns are used.

72.  The embossing calender consists of two rolls, one of which is hollow
engraved metal roll heated from the inside by a gas flame. The other is a
solid paper roll exactly twice the size of the engraved roll. The process
differs for the production of flat and raised designs.
 Flat designs are the simplest to produce. An embossed metal roll engraved
in deep relief revolves against a smooth paper roll. Fabric is passed
between the two rollers. The hot engraved areas of the roll produce a
glazed pattern on the fabric.
 Raised or relief or three dimensional designs require a more complicated
routine. After the design has been engraved on the steel roll the paper roll
is dampened and the machine is turned on, but the fabric is not passed
through. The pattern on the steel roll will be deeply impressed into the soft
paper roll.

73.  After the impression is sufficiently deep and the soft roll has dried, the
machine is turned off. The fabric is then fed through the rollers; both the
engraved roller and the shaped paper roll together mold the shape of the
pattern on to the cloth.
 Embossed designs provide surface texture at a lower cost than do woven
designs. Embossed fabrics should not be ironed as the design may be
diminished by pressing.

76.  Glazing or Friction Calendering- A special calender called a friction
calender is used to produce fabrics that have a highly glazed or polished
surface. Prior to passing the fabric
 through the calender, the cloth is saturated with either starch or resin. The
fabric is dried slightly then fed into the machine in which a rapidly moving
and a heated roller polishes the surface of the more slowly
 moving fabric. If starch is used to produce the glaze, the finish
 is temporary. If resins are used, the glaze is durable.

77.  Schreinerizing- The schreiner calender has a metal roller engraved
with 250 fine diagonal
 lines per inch visible only under a hand lens.This roller passes over the
fabric with pressure and heat, pressing the lines on the fabric to make a
regular surface with parallel lines, flattening the yarns and producing a
more opaque fabric with soft luster and hand.

79.  Moire- Moire fabrics have a watered or clouded surface appearance on
the face side of the fabric, which is sometimes called a “grain of wood”
pattern. To achieve an effective moire pattern, ribbed fabrics such as
taffeta, faille or bengaline are usually selected. Ribbed fabrics are
 doubed in such a way that thick yarns of one sided press
 and produce impressions on the other side. This, a „watered‟ design is
created due to difference in light reflection.

80.  f) Brushing- Brushing follows shearing to clean the surface of clear face
fabrics. When combined with steaming, it will lay nap or pile in one
direction and fix it in that position thus giving the up and down direction of
pile and nap fabrics.
 g) Gigging- Wool fabrics may be napped, or subjected to a raising
process called gigging.
 The fabric is first saturated with water. When the fibres of a moist wool
fabrics are raised they tend to curl and shrink. When brushed in one
direction, a smooth and lustrous appearance results.

81. ii) Finishes that alter appearance by chemical means:
 a) Burnt out or etched designs- Burnt out designs are produced by printing
certain chemicals on a fabric made of fibers from different fibre groups
(with different reactions to chemicals). Acids or ketones may be used as well
as aromatic alcohols such as phenols.
 When acids are used the fabric must be made of at least one fibre that is
easily destroyed by acids and other fibres that are highly resistant to them.

82.  A typical fabric used for acid, burnt-out patterns is made with such fibres
as rayon or acetate, which will be removed by the acid and wool, acrylic or
polyester which will be resistant to action by the acid.
 The fabric is exposed to the acid, which burns away or dissolves those
fibres subject to acid damage. The non affected fibres remain, resulting in
a fabric with pattern of sheer and opaque areas. Burnt-out designs can
also be made with acetone. This is used on fabrics composed of acetate
and a second fibre not affected by the acetone.
 The acetate is destroyed in the treated areas, leaving the second fibre with
an interesting design. Phenol is effective on fabric made partly of nylon;
the phenol will remove the nylon fibres, leaving the other fibres intact.

83.  b) Acid design (Localized parchmentizing)- In addition to stiffening the
fabric, the acid treatment of cotton fabric causes it to become more
transparent. This action can be utilized to create fabrics with a frosted
design. The design areas of the fabric are coated or
 printed with acid-resistant materials. When the acid finish is applied, acid
resistant areas retain their original opacity and remain opaque, while the
acid treated areas become quite transparent. It produces an opaque
design in contrast sharply with the transparent background.
 c) Plisse designs- A puckered or plisse effect is achieved in some fabrics
by imprinting them with chemicals that cause the fabric to shrink. When
these chemicals are printed in design, printed areas of the fabric shrink
while untreated areas pucker or puff up. The chemical is removed through
washing of the fabric. Cotton and rayon react in this way when treated with
sodium hydroxide (an alkali). Phenol is used for nylon to achieve plisse
 designs.

84.  Plisse fabrics should not be ironed because the
pressing of the plisse flatten the surface.

85. iii) Finishes that enhance comfort and after care
properties:
 a) Shrinkage control- A reduction in the length or width of a fibre, yarn or
fabric is known as shrinkage. Some fibres shrink naturally. Wool, animal hair
fibres and rayon are examples of such fibres.
 Most fibres however do not shrink because of inherent fibre qualities but
because they have been stretched during the processing of the yarns and
fabrics when tension is removed from these fabrics, the fabric relaxes and
returns to its original unstretched size and shape.

86.  Types of shrinkage
 The wetting of a fabric causes the tension that has been applied during the
 manufacturing of the fabric to be relaxed, so that fabrics generally shrink
after the first and up to the fifth laundering. This type of shrinkage is known
as relaxation shrinkage or fabric shrinkage. The warp yarns of woven
fabrics are subjected to greater tension than in the filling direction. Knit
goods tend to stretch more during manufacture than do woven goods
 and therefore knit goods are likely to shrink and change shape even more
than woven goods. A washable garment should not shrink more than two
per cent.

87.  Second type of shrinkage is progressing shrinkage which occurs during
subsequent washes.
 Cotton, linen and high-wet-modulus rayon exhibit relaxation shrinkage. No
progressive shrinkage.
 Regular rayon exhibit high relaxation shrinkage.
 Moderate progressive shrinkage. Wool exhibit moderate relaxation
shrinkage.
 High progressive shrinkage. Mechanical control methods or heat are used to
eliminate relaxation shrinkage and chemical control methods are used to
prevent progressive shrinkage.

88. Relaxation shrinkage and methods of control:
 Compressive shrinkage control- All woven fabric shrink when the strains of
weaving, warp yarn sizing and wet finishing are released when the fabric
gets wet in laundering.
 Compressive shrinkage control processes are used on woven fabrics of
cotton, linen and high-wet-modulus rayon.
 The trade marks for the various patented processes of the compressive
shrinkage type include Rigmel, Sanforized and Spring shrunk. These process
 generally guarantee less than 1-2% shrinkage.
 The internationally well known and most important shrinking process today
dates back more than 70 years. Though the correct expression for this
 process is controlled compressive shrinkage, commonly person knows it as
SANFORIZED.

89.  The process is a purely mechanical treatment without any addition of
 chemicals. The word SANFORIZED is derived from the first name of the
inventor of the compressive shrinkage process, Mr. Sanford L. Cluett.
 The purpose of the process is to shrink fabrics in such a way that textiles
made up of these fabrics do not shrink during washing.
 In this process the fabric is dampened and is then placed on a machine that
is equipped either with a continuous woollen or felt blanket or a rubber
pad. These pads are constructed so that they can be both stretched and
compressed.
 The fabric is carried on top of the blanket (or pad).
 The fabric meets the carrier at a point where the carrier is stretched around
a curve. As the carrier moves from the curve to a straight area, it squeezes
or compresses into a smaller, flat area.

90.  When the carrier compresses, the fabric it carries is also compressed. The
fabric is then set into this compressed position. The machine used are
engineered to provide the degree of compression needed for each type of
fabric.

91.  Damp relaxing/Steam relaxing/London shrunk: It is a 200 year old
relaxation finish for wool fabrics which removes strains caused by spinning,
weaving and finishing.
 Originally fabric was laid out in the field of the city of London and the dew
soothed away the stresses and improved the hand of the fabric.
 Although technique have been modernized, there is still much hand labour
involved.
 A wet blanket is placed on a long platform, a layer of cloth is then spread
on it and alternate layers of blanket and cloth built up.
 Sufficient weight is placed on top to force the moisture from the blanket into
the wool. The cloth is left in the pile for about 12 hours. The cloth is then
dried in a relaxed state. The tensions applied to the fabric during
processing are thereby removed. London shrinkage is done for fine worsted
fabrics not for woolens.

92.  Cylinder method: In this method, wool fabric is pressed across perforated
cylinders.
 Jets of steam are released through the holes in the cylinders, causing the
fabric to be dampened. The damp fabric, which relaxes in size is dried
without tension.

93. Progressive shrinkage and methods of control
 For wool: Wool and animal hair fibres are among those few fibres that
show progressive shrinkage. The wool fibre structure is the cause of
shrinkage, thus chlorination and resin coating methods are used which alter
the scale structure in some way.
 For Thermoplastic Fibres: Thermoplastic fibres are stabilized by heat
setting. If properly heat set, fabrics will exhibit no progressive shrinkage
and relaxation shrinkage will have been controlled also.
 For Rayon Fabrics: Shrinkage control for rayons is most effective when
compressive shrinkage control treatments are followed by a resin finish to
stabilize the fabric.

94.  b) Wrinkle Resistance- Resistance to wrinkling can be imparted to fabrics
by different means- First the fibre itself may be naturally wrinkle resistance
because of its resiliency. This is true for many synthetics and wool. Second
because of their construction, certain fabrics resist or disguise/cover up
wrinkling. Terry cloth (towel), knits, seersucker and
 plisse are such fabrics, Or special finish may be applied to fabrics to
improve their wrinkle resistance.
 Since cellulosic fibres are most prone to wrinkling, most wrinkle-resistant
finishes are applied to fabrics made from these fibres or their blends.
Finishing processes that have been designed to secure wrinkle resistance in
cellulosic fibres also utilize synthetic resins.

95.  Wrinkle resistance and recovery are achieved by chemical reactions
between the resins and the molecular structure of the fibre. The long chain
molecules of the fibre are cross linked through the actions of the chemicals
thereby providing greater stability in the position of the molecules and
preventing them from being too greatly deformed; or upon deformation
pulling them back into alignment, therby eliminating the wrinkles.
 The blending of cellulose with resilient synthetic fibres may have the effect
of improving wrinkle resistance.

96.  c) Permanent or Durable Press- The term permanent and durable press
are often used interchangeably by consumers, advertisers and the textile
industry. Durable press is a more accurate term, as some of these finishes
are diminished over the life time of the garment. I
 t is important to remember that although synthetic fibres may be blended
with cellulosics for durable press fabrics, the finish themselves react only
with the cellulose component. Durable press is a wrinkle recovery finish
designed for products made of cellulose fibres.
 Wrinkles are an undesirable character in fabrics caused by wear and
 washing. Creases and pleats are made by pressing and are added to a
garment for style effect. Durable press refers to the ability of a fabric to
retain an attractive appearance during wear and to return to an attractive
surface and shape after laundering.

97. DURABLE PRESS PROCESS

98.  d) Stain and soil resistance finishes- These help to maintain a clean look of
a textile product like carpets or upholstery. Chemicals such as fluorocarbons
and organosilicone compounds are used to coat the fabric surface.
 Thus, a protective coating is formed which inhibits penetration of stains and
soil. Another approach is to increase the surface tension so that the liquid
based stains roll-off in a manner similar to droplets on lotus leaves.

99. iv) Finishes that impart safety and protection:
 a) Water proof finish- Water proof finishes are those that coat or seal
fabric so that water does not pass through it. Such fabrics are
impermeable to air and thus in general are not comfortable in terms of
wearing apparel.
 Water proof fabrics are generally coated with rubber or a synthetic plastic
material. Water proofing is nothing but preventing the passage of both air
and water through a fabric. Used in tarpaulin, umbrella cloth, resin coat
fabric
 etc. It is a chemical finish and the chemical used are-
 • Coating thin film with vulcanized natural rubber
 • Synthetic resin (polyvinyl chloro acetate, polyvinylidine chloride, cellulose
acetate)
 • Coating of water impermeable substances like asphalt and molten wax
 • Wax emulsion

100.  b) Water repellent finish- If a fabric allows air but prevents water to pass
through itself, it is known as water repellent finish. A water repellent fabric
is resistant to wetting but if the water comes with enough force it will
penetrate the fabric.
 The water repellent finish alters the surface tension properties of the fabric,
which causes moisture to form into tiny balls of
 water and roll off without passing through the fabric. Wax emulsions or
metallic soaps are used to secure renewable water repellency. Silicon
compounds are effective in producing durable water repellent fabric.

101.  c) Flame Retardant Finish- Finishes that reduce the flaming, charring or
afterglow of fibres and fabrics are important for safety. Most fabrics
finished with flame retardants still will burn in the direct path of flame;
however they self-extinguish when the source of flame
 is removed. The important characteristic is that they do not propagate the
flame. A truly fireproof fabric will not burn even in the path of direct flame,
but actually only asbestos and glass fibres have this property.
 Beside this certain synthetic fibres that have been developed for the
aerospace industry, such as Kevlar and Nomex aramid are also fireproof.
Finishes cannot provide completely safe products. They can reduce the
danger of complete destruction of the treated fabrics. These finishes are
applied on wearing apparel, carpet, mattresses. children sleepwear,
curtains, window shades, lamp shade etc.

102.  Synthetic fibres can be modified to reduce flammability by the addition of
flame-retardant materials to the solution prior to extrusion. Out of these
relatively few have attained commercial significance.
 Man-made cellulosic fibres with flame-retardant additives have
 been more successful. Flame-resistant rayon, cellulose acetate, and
triacetate are available. In addition to these so-called “durable fire-
retardant finishes”, a solution of 30 per cent boric acid and 70 per cent
borax can be used as a rinse for products. This rinse will provide temporary
flame retardancy, but it produces a decrease in the softness and
 drapability of the fabric to which it is applied.

105. Dyeing & Printing
 Dyeing is a method which imparts beauty to the textile by applying various
colors and their shades on to a fabric. Dyeing can be done at any stage of
the manufacturing of textile fiber, yarn, fabric or a finished textile product
including garments and apparels.
 The property of color fastness depends upon two factors- selection of
proper dye according to the textile material to be dyed and selection of
the method for dyeing the fiber, yarn or fabric.

106.  Ever since primitive people could create, they have been endeavoring to
add color to the world around them.
 They used natural matter to stain hides, decorate shells and feathers, and
paint their story on the walls of ancient caves. Scientists have been able to
date the black, white, yellow and reddish pigments made from ochre used
by primitive man in cave paintings to over 15,000 BCE.
 With the development of fixed settlements and agriculture around 7,000-
2,000 BCE man began to produce and use textiles, and would therefore
add color to them as well.

107.  Although scientists have not yet been able to pinpoint an exact time where
adding color to fibers first came into practice, dye analysis on textile
fragments excavated from archaeological sites in Denmark have placed the
use of the blue dye and red dye in the first century.
 Primitive dyeing techniques included sticking plants to fabric or rubbing
crushed pigments into cloth. The methods became more sophisticated with
time and techniques using natural dyes from crushed fruits, berries and
other plants, which were boiled into the fabric and gave light and water
fastness (resistance), were developed.

108.  Some of the well known ancient dyes include madder,
 a red dye made from the roots of the Rubia tinctorum,
 blue indigo from the leaves of Indigofera tinctoria,
 yellow from the stigmas of the saffron plant, and dogwood, an extract of
pulp of the dogwood tree.
 The first use of the blue dye, woad, beloved by the Ancient Britons, may
have originated in Palestine where it was found growing wild.
 The most famous and highly prized colour through the age was Tyrian
purple, noted in the Bible, a dye obtained from the shellfish.
 A bright red called cochineal was obtained from an insect native to Mexico.
All these produced high-quality dark colours.
 Until the mid-19th century all dyestuffs were made from natural materials,
mainly vegetable and animal matter.

109.  Today, dyeing is a complex, specialised science. Nearly all dyestuffs are
now produced from synthetic compounds.
 This means that costs have been greatly reduced and certain application
and wear characteristics have been greatly enhanced. But many
practitioners of the craft of natural dying (i.e. using naturally occurring
sources of dye) maintain that natural dyes have a far superior aesthetic
quality which is much more pleasing to the eye.
 On the other hand, many commercial practitioners feel that natural dyes
are non-viable on grounds of both quality and economics. In the West,
natural dyeing is now practised only as a handcraft, synthetic dyes being
used in all commercial applications. Some craft spinners, weavers, and
knitters use natural dyes as a particular feature of their work.

110. THEORY OF DYEING
 Dyeing is the process of colouring textile materials by immersing them in an
 aqueous solution of dye, called dye liquor. Normally the dye liquor consists
of dye, water and an auxiliary.
 To improve the effectiveness of dyeing, heat is usually applied to the dye
liquor.
 The general theory of dyeing explains the interaction between dye, fibre,
water and dye auxiliary. More specifically, it explains: a. Forces of repulsion
which are developed between the dye molecule and water.
 b. Forces of attraction which are developed between the dye molecules and
fibres. These forces are responsible for the dye molecules leaving the
aqueous dye liquor and entering and attaching themselves to the polymers
of the

111. DYES & THEIR CLASSIFICATION
 Colour is usually the primary consideration when purchasing clothing,
carpets, draperies, and furniture. Colour has always been important in
textiles. Until 1856 natural dyes and pigments were used as colouring
agents. These dyes and pigments were obtained from plants and insects.
 In 1856 William Perkin, a young chemist, discovered the first synthetic
dye, the reddish purple “Mauveine”, a whole new industry came into
existence.
 Colour is a visual sensation. It results from the reflectance of certain visible
light rays that strike to retina and stimulate cells in the nerves of the eye.
The nerves send a message to the brain, which in turn produces the
sensation of a specific hue and we see colour. When all the visible light rays
are reflected, object appears white; if none of the rays are
 reflected, it appears black.

112.  When one or more rays are reflected the viewer senses the
 colour produced by the specific reflected ray or combination of rays.
 In other words, coloured compound containing auxochromes become dye.
Thus dye is a compound that can be fixed on a substance in a more or less
permanent state and that evokes the visual sensation of a specific colour.
 Pigments are insoluble colour particles that are held on the surface of a
fabric by a binding agent. Their application is quick, simple, and
economical. Any colour can be used on any fibre, since the pigments are
held on mechanically.
 Dye must be in small particles that can be thoroughly dissolved in water or
some other carrier in order to penetrate the fibre. Undissolved particles
stay on the outside and the colours then have poor fastness to crocking and
bleeding.

113.  Classification of dyes
 Dyestuffs are divided into a number of classifications. The ability of the
fibres to accept each of these dye classes depends upon several factors.
 One is availability of appropriate chemically reactive groups in both the
fibre and the dyestuff.
 The other is chemical composition of the dye liquor. Dye that must be
applied in an alkaline medium is difficult to
 use on protein fibres because the alkalinity of the dye bath may harm the
fibre. Likewise dye bath that are strongly acid may be harmful to cellulose
fibres.

114.  Classification of dyes on the basis of their fibre suitability
 1. Dyes most often used on cellulosic fibres: Azoic or naphthol dyes,
direct dyes, vat dyes, reactive dyes, sulphur dyes, mineral colours and basic
dyes with mordants.
 2. Dyes for protein fibres: Acid dyes, basic dyes (without the use of
mordants), acid mordants dyes, metal complex dyes, reactive dyes.
 3. Dyes for cellulosic as well as protein fibres: basic dyes, reactive dyes.
 4. Dyes used for acetate, triacetate and polyester fibres: Disperse and
pigment colours
 5. Dyes for acrylic fibres: Basic (cationic dyes)
 6. Dyes for polyamide fibres: Acid dyes, metal complex dyes, disperse
dyes

115. Classification of dyes on the basis of their source
 1. Natural dyestuffs
 The coloring of fibers results from the interaction of the functional groups
within the fibers and those within the dyestuff and/or a fitting of the dye
and fiber molecules together. With natural dyes, this could be overcome by
a treatment of the fabrics with appropriate natural
 acids or oxides that did, however improve their colourfastness. These
substances, called mordants, react with the dyestuff to form an insoluble
compound, thereby “fixing” the colour within and on the fiber.
 Natural dyes are the dyes obtained from natural sources. Vegetable dyes
could be made from flowers, leaves, berries, barks, roots, grasses, weeds,
and lichens. The difficulty with most of the natural dyestuff was that they
lacked colour fastness. The treatment of the fabrics with certain natural
acids oxides did improve their colour fastness. Some mordants
 were more effective on animal fibers such as silk and wool; others were
preferable for cotton and linen. Aluminum produces pinks and bright reds,
while iron produces purple

116.  The treatment of the fabrics with certain natural acids oxides did improve
their colour fastness. Some mordants
 were more effective on animal fibers such as silk and wool; others were
preferable for cotton and linen. Aluminum produces pinks and bright reds,
while iron produces purple
 and black colours.