Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/15/2003
Publication Date: 5/15/2003
Citation: Sawhney, A.P. 2003. Effect of Washing and Drying of a Cotton Warp nn the Yarn's Tensile Characteristics and Weavability. Proceedings: National Cotton Council Beltwide Cotton Conference. p. 2179-2181. Interpretive Summary: Since time immemorial, cotton warp yarns have been slashed with an adhesive size mixture that is mainly comprised of an ordinary starch, modified starch (CMC), or polyvinyl alcohol (PVA) to assist efficient weaving of the yarns into a quality woven fabric. However, a fabric made with a sized warp must be scoured and desized to completely remove all the chemical ingredients of the size mixture in order to achieve satisfactory bleaching, dyeing, and/or any other special chemical finishing. Both of these centuries-old processes, viz., the warp sizing and the fabric desizing in cotton textile manufacturing are costly, complex, and more importantly, environmentally sensitive. Accordingly, the textile industry wants to eliminate warp sizing, which automatically would also eliminate the necessity for fabric desizing as well. The scientists at SRRC have developed some new concepts and research approaches to try to achieve size-free weaving. One of the research approaches was to wash (with a soap/detergent) and dry (under a nominal tension stretch) the cotton warp to eliminate natural stickiness of greige cotton (which causes fiber-to-fiber and yarn-to-yarn entanglements during weaving) and to set twist liveliness (torque) of the yarn, both of which are critical yarn conditions for efficient weaving. Results of preliminary research investigations have revealed that the tensile strength of an appropriately washed and dried cotton warp is almost 20% greater than that of the yarn in its greige state. Also, the weavability of the (size-free) washed and dried warp was unexpectedly satisfactory. However, a lot more weaving, under somewhat controlled conditions, on a modern weaving machine is needed to conclusively establish that the washing and drying of a cotton warp indeed assists in all types of yarns, fabrics, and weaving machines. Yarn producers will benefit from the reduce cost associated with low sizing operations. Consumers will benefit from the fact that reduce sizing will cause less water pollution and result in cleaner streams and water courses.
Technical Abstract: In a continuous process, a warp of 100% cotton yarn was uninterruptedly washed in boiling water containing a soap and a wetting agent and dried under a nominal tension/stretch on three (3) steam heated (200F) cans on a conventional "dummy" slasher (i.e., without using a sizing mix) before being wound on to a loom beam. The beam was installed on a slightly modified fly-shuttle loom and the (size-free) washed warp was woven, under almost mill-like speed and conditions, into an open-construction twill fabric. The warp yarn was tested, mainly for its tensile characteristics, before and after the washing and drying and the washed warp was evaluated for its weavability. Results have shown that the tensile breaking strength of the washed/dried yarn is about 20% greater than that of the original, greige yarn and the weavability of the washed warp is satisfactory, although it cannot be positively determined at this time that the satisfactory weaving performance of the warp indeed was due to the increased yarn strength alone. About 65 meters of an open twill fabric was woven without a single yarn failure.