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Finishing Chemicals Textile materials undergo several chemical treatments from the raw stage to finished product. These processes (desizing, scouring, bleaching, dyeing, washing etc.) cause the surface of the fibres to become rough and harsh. This leads to the fabric having an unpleasant feel. To solve this problem textile materials are treated with substances, called "Softeners" which give a pleasant feel. Pre treatment chemicals are used to convert raw fibre, yarn, or fabric into substrates suitable for dyeing, Printing and finishing. These fibres/yarns/fabric could be of cotton, wood, silk, synthetics and blends of these. The pre-treatment processes include.
- Desizing
- Scouring/wetting (removal of oils, waxes, dirt, etc. thus imparting absorbency)
- Bleaching (removal of natural colouring matter)
- Mercerizing (increasing dye-ability, lustre and strength).
Pre-Treatment Requirements are as follows
- Uniformity and levelness of effects
- High absorbency
- Low ash content
- Freedom from size
- High degree of whiteness
- Absolute absence of husks
- High dye absorbing power
Thus Pre-treatment occupies a critical position in wet processing. More than 60% of the problems encountered in finished fabrics are directly attributed to lack of proper preparation.
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