Fabric desizing

Plasma may be used for removing the contaminants, finishing and sizing agents from the fabric. Desizing of polyester fabric that used polyvinyl alcohol as the sizing agent can be removed by plasma treatment [63]. 

The fabric is desized after the weaving operation and then passed through a heated water bath to remove all the size. The rate at which this operation can be accompHshed depends to a great degree on solubiUty rate of the poly(vinyl alcohol). Difficulties encountered in completely removing the lubricating wax, usually tallow wax, has led to the development of several wax-free size compositions (303—311). The main component contained in these blends is PVA in combination with a small amount of a synthetic water-soluble lubricant. 

Enzymatic desizing is one of the oldest nonfood appHcations of commercial amylases. Another type of enzyme, microbial ceUulases, has developed within the textile iadustry as a tool for fabric finishing, ia particular for denim garment finishing. CeUulases can achieve the fashionable worn look traditionaUy obtained by the abrasive action of pumice stones, ie, stone-washing. 

Enzymes have traditionally been closely associated with the desizing of cellulosic fabrics. In recent years, however, the sphere of possible, if not actual, uses has widened considerably. 

To desize oxidatively by a batchwise process, the oxidant must be added when the alkaline fabric reaches top temperature. 

The above recommendations are for caustic scoured or peroxide desized fabrics. For fabrics not so treated, the amounts of caustic and peroxide should be increased by 50% [143]... 

Before weaving, the warp is covered with a layer of polymer to withstand the mechanical stress (abrasion, tension) during weaving. These polymer coatings are so-called sizes. Normally native starch, modified starch like carboxymethyl-starch (CMS), carboxymethyl-cellulose (CMC), polyvinylalcohols (PVA), polyacrylates, and proteins can be used. The amount of added polymer for staple yarns like Co is between 8 and 20% of the weight of the warp. As a result, in many cases the final amount of polymer to be removed in the desizing step is approximately 5-10% of the weight of the fabric. 

Desizing of m = 1000 kg of goods, which contain 5% of weight starch size p = 0.05) cause a load Lcod = 50 kg and Lbod = 30 kg. Using 10 L of water for desizing of 1 kg of fabric, a total volume of 10,000 L will be required and the load Lcod = 50 kg will be diluted in this volume. As a result, a COD value of 5000 mg/L can be calculated for the effluent. 

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