Submitted to: International Conference on Composites Engineering Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 15, 2003
Publication Date: July 1, 2003
Citation: Sawhney, A.P. 2003. Prospects of Reducing or Eliminating Sizing Adhesive Materials in Cotton Textile Manufacturing. International Conference on Composites Engineering Proceedings. 637-638. Interpretive Summary: For centuries, cotton fabrics have been woven in textile mills by coating the warp yarn with a size mixture containing an adhesive, such as starch, in order to assist efficient weaving. However, since the chemicals used in a sizing mixture adversely interfere with the chemicals used in the subsequent fabric finishing treatments, a fabric woven with a sized warp yarn must be desized at the first opportunity to completely remove all the size ingredients in order to achieve satisfactory quality of fabric bleaching, dyeing, and/or special finishing. Sizing and desizing processes use tons of expensive chemicals, consume a lot of energy and water, and generate a large amount of waste water (which must be appropriately treated for its safe disposal). Since these two processes in the fabric production chain are very costly, complex, and environmentally sensitive, the cotton textile manufacturing industry obviously wants to reduce or eliminate the main, underlying process of yarn sizing, which would automatically eliminate the need for fabric desizing as well. Scientists at SRRC have developed a multi-pronged research approach to try to eliminate the warp sizing. The approach basically involved improving yarn quality and structure, developing a simple method of cleaning and twist-setting the yarn (without the traditional warp sizing), modifying critical loom components to minimize yarn abrasion during weaving, and fundamental understanding of certain yarn failures. The results of very preliminary size-free weaving investigations have been extremely encouraging in the sense that about 50 yards of a 100% size-less cotton fabric was woven on a commercial loom, operating under mill-like conditions and speed, without a single warp yarn failure for the first time ever, which is a significant research accomplishment and an important milestone in cotton textile processing.
Technical Abstract: Since time immemorial, cotton warp yarns (singles have always been temporarily sized or coated with some sort of adhesive such as starch, CMC, PVA, along with several other chemicals, to achieve efficient weaving of the yarns, mainly by improving their abrasion resistance against the harsh mechanical actions and stresses associated with the weaving mechanism. Since the chemicals used in a size mixture can adversely affect quality of bleaching, dyeing and/or any special finishing of the fabric in the subsequent processes, they must be completely removed at first opportunity by a process called fabric desizing. Both the warp sizing and the fabric desizing processes use, or waste, tons of expensive chemicals, consume a lot of energy and water, and generate a lot of waste water which must undergo an expensive treatment before it can be safely disposed. Thus, both of these centuries-old processes are very costly, complex and environmentally sensitive. Today's ailing textile industry obviously wants to reduce conventional sizing and preferably eliminate the underlying process of warp sizing to reduce fabric production cost as well as improve the ecological balance. The National Cotton Council of America has given a high research priority to achieve the so-called "size-free weaving." Although the subject of warp sizing has been extensively investigated for centuries to improve sizes, sizing formulations, and slashing machinery and practices in order to improve weaving efficiencies, no significant work on eliminating the warp sizing has been reported in recent years. In fact, the "size-less or size-free weaving" of cotton yarns simply does not exist. A few researchers in the past has attempted to either reduce conventional warp sizing or replace it with some sort of permanent sizing (which would not interfere with the subsequent chemical processes and would beneficially stay on the fabric during its entire useful life), but they have been largely unsuccessful.