Investigation on the Effect of Heat setting on Twist Liveliness and Tensile Properties of Cotton-Covered Polyester Core Spun Yarns

Core-spun yarns can be produced by ring، rotor، friction، and air-jet spinning systems. Production of core-spun yarns on ring spinning system is known as the oldest one. The aim of this study is to investigate the effect of dry and saturated steam heat setting on twist liveliness and tensile properties of core-spun yarns containing cotton fiber as sheath and 70 denier fully drawn multifilament polyester yarn as core part. Pre-tension of core part was changed in two levels i. e. 0 and 45g and English twist factor was also varied in 3. 5 and 4. 0. On the other hand، 120، 150، and 180°C were selected as dry heat setting temperature. Totally، 16 different samples were tested. The twist liveliness and tensile tests were carried out on samples before and after heat setting process and then obtained results were evaluated statistically using one-way analysis of variance، Tukey and Duncan tests. The dominant reduction of twist liveliness after heat setting was observed and the samples treated with saturated steam heat setting have the lowest values of twist liveliness.