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Pretreatment Chemicals are used to convert raw
fiber/yarn/fabric into substrates suitable for dyeing, printing and finishing.
These fibers/yarns/fabrics could be of cotton, wool, silk, synthetics and blends of these.
The pretreatment processes include: Desizing (Removal of size), Scouring/wetting (removal of oils, waxes, dirt etc. thus imparting
absorbency), Bleaching (removal of natural colouring matter) and
Mercerizing (increasing dye ability, luster and strength).
Pretreatment requirements are as follows:
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Uniformity and levelness of effects
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High absorbency
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Low ash content
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Freedom from size
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High degree of whiteness
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Absolute absence of husks
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High dye absorbing power
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Thus Pretreatment occupies a critical position in wet processing. More than 60% of problems encountered in finished fabrics are directly attributed to lack of proper preparation.
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