1. Introduction to Textile Preparation
Assistant Professor Dr. Apichart Sonthisombat,
Rajamangala Institute of Technology
Copyright © 2004 Assist. Prof. Dr. A.
Sonthisombat All rights reserved.
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2. Basic Textile Definitions
Fibers = A smallest unit of textile materials.
Usually classified by flexibility, fineness, and
a ratio between length and diameter (L/D
ratio)
Natural Fibers = Fibers that come from
animals (wool, silk etc.), plants (cotton, flax,
hemp, jute etc.) or mineral material(asbestos).
Synthetic Fibers = Man-made fibers or
artificial fibers which is usually comes from
chemical agents.
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3. Semi-synthetic Fibers = Fibers that comes
from solutions of natural polymer or
derivatives from the natural polymer
(cellulose, protein etc.)
Polymer = Macro molecules containing
small chemical units (named “Monomer”)
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4. Staple Fibers = Fibers from natural or
synthetic fibers which were cut into short
fibers. Normally, natural fibers are staple
fibers (expected silk fibers). These fibers
have 5-500 millimeters long.
Filament Fibers = Fibers from natural or
synthetic fibers which have infinite length.
Silk Fibers are the only one natural fibers
classified in this definition since their length
between 700-1500 meters depending to their
races.
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5. Yarns = The combinations of fibers using
some twisting (Z and S twists) in order to
make strong and stable yarns.
Spun Yarns = The yarns that come form
staple fibers.
Filament Yarns = The yarns that come from
filament fibers (mono-filaments and multi-
filaments)
Fabrics = The products of weaving, knitting
or non-woven processes. Normally, fabrics
have a certain thickness and can withstand
tear and tensile forces.
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6. Textile Preparation is the heart of the textile
dyeing, printing and finishing processes beca
use fibers, yarns or fabrics have many impurit
ies (i.e. cotton wax, starch, lubricant, silk seri
cin, wool oil etc.) as a proverb “Well begin i
s half done”. From the experience, more than
60% of the faults from these factories come fr
om preparation.
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7. The Examples of preparation processes of
cotton and its blends fabrics
100% Cotton fabrics
1. Singeing
2. Desizing (only for woven fabrics)
3. Scouring
4. Bleaching (only for pale or bright shades)
5. Mercerizing
6. Adding of Optical Brightening Agent
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8. 100% Silk Fibers
1. Degumming (to get rid of non-fibrous
materials (sericin))
2. Bleaching (to make the goods whiter)
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9. 100% Wool Fibers
1. Carbonising (to remove leave, bark and
other parts of the plants from the wool fibers)
2. Scouring (to get rid of fat and oil from the
fibers)
3. Bleaching (to make the fibers whiter)
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10. Morphology of Textile Fibers
1. Crystalline Regions are the regions that
cannot absorb water, humidity and dyestuff
solutions but they are the part for fiber
strength.
2. Non-Crystalline Regions or Amorphous
regions are the regions that can absorb water,
humidity and dyestuff therefore they can be
dyed but they are a very weak part of the
fibers.
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11. 3. Orientation of the Crystalline Regions
alongside the fiber axis
This property is very important in that it will
increase the tensile strength of the fiber if it
presents in the optimal quantity.
Crystalline
Amorphous Void space
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12. Singeing Process
Singeing is a process that uses gas flame or
hot plate in order to get rid of small fibers
protruding (hairs) on the fabrics (these
fibers normally come from spun yarns).
Objectives:
1. To get rid of the small fibers
2. To make the fabrics smoother than before
3. To help the printing ink or dyestuff to
make clearer marks on the fabrics
4. To improve rubbing fastness and washing
fastness of the dyed or printed fabrics
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13. Where does starch come from?
Starch or Size is a material that help the
weavers to ensure that their warp yarns are
not broken or struggle with the reeds.
Therefore these will leading to low
productivity and high machine break-down
rate.
Desizing process
This will get rid of the starch or size covering
the warp yarns using enzymes, oxidizing agen
t, or other chemicals.
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14. As the starch or size covering the warp yarns,
it will lead to uneven dyeing, printing or
finishing. No need for this material on our fa
brics. (Note this will effect only weaving pro
cess. For knitting process, no starch or size o
n the fabrics thus no need to desizing.)
Objectives
1. To get rid of starch from sizing of the warp
yarns
2. To ensure levelness of the dyestuff or
printing ink. If not taken out completely, it w
ill affect washing and rubbing fastness of the
fabrics. 14

15. Scouring Process
Scouring process is a process designed to
remove natural fat, wax, oil from the cotton
fabrics using sodium hydroxide and detergent
at boil for 20-30 minutes. Synthetic fabrics
and other protein fabrics may use only
sodium carbonate (weaker alkali) instead.
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16. Objectives
1. To remove natural fat, wax, and oil
materials containing in the fabrics without
damaging the fibers
2. To accelerate dye and chemical absorption
of the fabrics
3. To improve the handle of the goods
(softer)
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17. Bleaching Process
The process is to make the goods whiter than
before. This will help the goods to absorb
more dyes and chemical and also make the dye
on the goods brighter. Normally, for cotton
fabrics, hydrogen peroxide in alkali solution at
boil are the most popular bleaching agent.
Objectives
1. To whiten the goods
2. To make the goods to be suitable for dyeing
and printing with pale or bright shade
3. To be follow with adding optical brightening
agent process (super white) 17

18. Mercerizing Process
The is to make the cotton goods more luster
than before using sodium hydroxide solution
in cold condition and tension. This will lead t
he cotton fibers to be swollen and increased s
trength. Also this will improve dye absorptio
n of the fibers. John Mercer was the first che
mist in the world who found this phenomeno
n in 1844. Therefore, the process was called
“Mercerizing”
Caustizing is the process nearly the same as
mercerizing but it uses lower concentration of
the hydroxide solution and without tension.
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19. Objectives
1. To make the goods more luster because
raw cotton fibers are ribbon-like. After this
process, the fibers change to cylindrical shape
resulting more evenness reflected light from
the goods.
Before After
2. To improve dyeability of the goods about
5-10%.
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20. Adding Optical Brightening Agent
The process is to add special dyestuff into
textile or paper to make them brighter when l
ooking at black-light light bulb or natural sun
light. As the dyestuffs are colorless but usin
g UV light to excite these dyes. They will re
flect the light at the wavelength that human c
an see (i.e. blue, violet). So the goods look b
righter and whiter.
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