Scouring of Cotton Fabrics

Mixed Enzymatic Process in Scouring of Cotton Fabrics... 

The type of alkali used for scouring of cotton depends on the quality of goods. For example, if coloured yams present in the fabric, sodium carbonate is ideally suited because of its low pH. Cotton yams to be dyed in dark shade should be scoured with 1-2% sodium carbonate solution for 30 min in presence of wetting agent. 

Scouring and bleaching of cotton fabrics are also attractive targets for enzyme-based processes, due to the severe environmental impact of these processes. These processes are also very energy demanding. Raw cotton contains about 10% of impurities. Pectins, waxes and coloured components can all be partially removed from raw cotton by enzymatic treatments but the residual seed coating remains a problem. 

SEQ 100 is used in preparation of cotton and cotton blend fabrics and also can be used in scouring synthetic fabrics when there is a substantial amount of interfering heavy metals on the fabrics. A concentration of 0.1% on the weight of the bath in the caustic scour prior to peroxide bleaching will remove calcium, magnesium and copper but very little iron as the metal or as the rust. If it is necessary to remove ron or rust, other products such as SEQ CF in strong caustic are recommended. 

Venn obtained very little levoglucosan from the pyrolysis of raw cotton, whereas washing with water increased the yield to 28 %, and further prepurification by treatment with dilute alkali and acid provided a yield of 38%. Holmes and Shaw found that a cotton fabric purified by scouring and bleaching provided more tar and less char on vacuum pyrolysis than the reference materials. A Russian patent" claims that the heat resistance of cellulose is greatly increased by lowering the content of alkali metals to 0.03 — 0.05%. 

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