This document provides an overview of preparatory processes in textile chemical processing. It discusses the stages involved which include grey checking, stamping, mending, shearing, singeing, desizing, scouring, bleaching and optical whitening. Specifically for cotton materials, it describes how singeing removes protruding fibers, desizing removes sizing added during weaving, and scouring removes natural impurities. Bleaching then removes natural colors like yellow, while optical whitening eliminates any remaining yellow hue.

1. Introduction to Preparatory Processes
in Textile Chemical Processing
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2. Government College of Engineering & Textile Technology,
Berhampore
Department of Textile Technology
Prepared By….
SK RAJU
Contact info :
Mob no: +91 9007818745
Email id- skraju230@gmail.com
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B.Techin Textile Technology
Pass out year - 2017
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3. Topics Covered :
• Overview of colouration and finishing or chemical processing of
textile materials,
• Overview of different stages,
• Preparation of cotton/cellulosic materials,
• Prelims of preparation: grey checking-grey testing-stamping-
mending-stitching-shearing/cropping.
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4. Overview of colouration and finishing or
chemical processing of textile materials
Uncoloured
Raw Material
• Impurities are present
Preparatory
Process
• Remove Impurities and prepare the
material for further processes.
Coluration • Imparts colour by means of dyeing or printing.
Finishing
• To provide the material with the properties that the
end use demands.
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5. Overview of different stages of Pre-treatment
Grey
Checking
& Grey
Testing
Stamping
Mending/
Stitching
Shearing/
Cropping
Singeing
Desizing
Scouring
Bleaching
Optical
Whitening
( for white
product
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6. Prelims of preparation
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7. Grey fabric
• It’s the fabric coming from the loom state, no chemical
processing is applied on it.
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8. Grey Checking & Grey Testing
• Here the fabric is checked carefully that is there any
deformities or not. Here the yarn density, number of
ends & number of picks per unit length, yarn strength
is also examined. Proper repairing of the fabric is also
done here.
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9. Stamping
• Here the fabric is stamped or marked as per it’s
category and quality.
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10. Mending or Stitching
• After stamping the fabrics are stitched together according to their
category or quality. 100-300 pieces of fabrics are joined together.
The length of one fabric is approximately 60-700 m. The speed of
this mending or stitching operation is around 60-70 m/ minute.
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11. Shearing or Cropping
• Shearing is an operation consists of cutting the loose
strands of fibres from either surface of a fabric with a
sharp edged razor or scissors. Good cropping reduces
the tendency of blended fabrics to 'pill'.
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12. Preparation of cotton/cellulosic
materials
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13. Singeing
• The aim of singeing is to burn-off the protruding fibres
and hairs from the fabric surface. This process is
mainly done by gas flame.
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14. Desizing
• The aim of desizing is to remove the sizing contains of
the fabric which was applied at the warp yarns of the
fabric at the time of weaving.
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15. Scouring
• The aim of scouring is to remove all the natural impurities mainly
the hydrophobic impurities.
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16. Mercerisation
• This process makes the fabric shiny and increase the
strength of the fabric.
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17. Bleaching
• The aim of bleaching is to remove the natural colours
i.e. some yellowish colour of the fabric.
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18. Optical Whitening
• Even well bleached fabrics possess a slight yellowish appearance.
• This yellowish hue of the materials can be eliminated by whitening
with optical brighteners or fluorescent brightening agents (OBA or
FBA.
• Blueing agents are also used for the same purpose.
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19. References :
• S.R. Karmakar, Chemical Technology In The Pre-treatment
Processes Of Textiles.
• Andrea Wynne, The Motivate Series : Textiles
• slideshare.net
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