Standardization of process variables for the production of void raw silk using bivoltine cocoons and Japanese PVA yarn

Abstract

　　A new concept of production of bulky void silk has been developed by introducing PVA yarn in the process of silk reeling in the modified multiend reeling machine. The bivoltine cocoons along with Japanese PVA yarn is used for the production of void silk. Using the Box and Behnken design of experiments the process variables viz., Number of cocoons, croissure length, reeling basin water temperature and reel speed have been standardized with 27 combinations of experiments. The study indicates that process variables significantly influence the reel performance and quality of void silk produced viz., reelability, raw silk recovery, waste percentage on silk weight, average size and yarn thickness. The void silk produced was twisted and later degummed and the quality parameters viz., denier, tenacity, elongation, yarn thickness and bulk density were studied. The results indicate that process variables significantly influence the quality characteristics of twisted and degummed void silk. Based on the response optimization in statistical analysis, it was observed that 30 bivoltine cocoons reeled per end with 6 mm croissure length, 50°C basin temperature and reel speed of 100 m/min is ideal for the production void raw silk on modified multiend reeling machine. The void silk was used as weft in the production of bulky silk fabrics.