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- skraju230@gmail.comLinkedin 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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