introduction to preparatory processes in textile chemical processing
TRANSCRIPT
Introduction to Preparatory Processes in Textile Chemical Processing
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Government College of Engineering & Textile Technology,Berhampore
Department of Textile Technology
Prepared By….SK RAJU
Contact info :Mob no: +91 9007818745Email id- [email protected] Id- https://www.linkedin.com/in/sk-raju-757140113Facebook id- https://www.facebook.com/skraju231Twitter id- https://twitter.com/SkRaju231
B.Tech in Textile TechnologyPass out year - 2017
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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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Overview of colouration and finishing or chemical processing of textile materials
UncolouredRaw 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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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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Prelims of preparation
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Grey fabric
• It’s the fabric coming from the loom state, no chemical processing is applied on it.
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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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Stamping
• Here the fabric is stamped or marked as per it’s category and quality.
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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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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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Preparation of cotton/cellulosic materials
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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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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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Scouring
• The aim of scouring is to remove all the natural impurities mainly the hydrophobic impurities.
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Mercerisation
• This process makes the fabric shiny and increase the strength of the fabric.
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Bleaching
• The aim of bleaching is to remove the natural colours i.e. some yellowish colour of the fabric.
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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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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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