Pretreatment of cotton yarns using UNIV-AIO |
Posted: November 6, 2017 |
INTRODUCTION Cotton is most important natural fiber whose consumption is constantly increasing day by day. Natural cotton is hydrophobic and colored. Scouring is a purifying treatment of textiles. The objective of scouring is to reduce the amount of impurities sufficiently to obtain level and reproducible results in dyeing and finishing operations.
Scouring of cotton textiles is an essential treatment in textile wet processing in order to get high absorbency. During scouring, waxes and other hydrophobic materials are removed from the cotton fibres. Conventionally, scouring is done with hot aqueous solution of caustic (NaOH) to remove hydrophobic components from the primary wall (e.g. pectin, protein and organic acids) and the cuticle (waxes and fats). Though alkaline scouring is effective and cost effective process, it is inefficient because it consumes large quantities of water and energy.
Also, Hydrogen peroxide (H2O2) is most popular oxidant used to remove natural colorant of cotton fibres. Generally, combined scouring and bleaching is carried to make cotton fiber hydrophilic and white. Conventionally, scouring and bleaching is done with aqueous solution of caustic and H2O2 at boil.
The conventional pre-treatment process of yarn requires strong alkali viz. caustic soda for bleaching. The main reason to use this strong alkali is to get high absorbency. It is well known fact that caustic has property to make the yarn harsh and hairy which makes it difficult to run yarns on looms. Further, during dyeing also there is strong alkali used for fixation. This also gives additional harshness to the yarn. To reduce the harshness of yarn, the softener is used in the final process. It improves the lubricity of yarn which reduces coefficient of friction. However, the yarn still needs waxing treatment to remove hairiness and make suitable to run on the loom. To overcome these drawbacks, SAREX has introduced a new concept for cotton yarn processing to get better productivity on looms with good end use performance. Univ-AIO acts as bleach activator and provides required alkalinity to achieve absorbency just sufficient for dyeing. It replaces most of the bleaching auxiliaries. Unique Features:
Recommended dosage: Recipe for RFD yarn (Ready for Dyeing yarn) : Univ-AIO : 1.5-2.5% Hydrogen peroxide (50%) : 1.5-3% Temperature : 95-110°C Time : 15-45min
Recipe for Full white yarn: Univ-AIO : 1.75-2.5% Hydrogen peroxide (50%) : 6-8% Temperature : 95-110°C Time : 45-90min
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