A comparative study of nylon 6 tyre yarns produced by conventional two-stage and spin-draw processes

25-28Nylon 6 tyre yarns of 1260 denier were obtained using conventional (spinning, draw twisting) and spin-draw routes. The polymers, spinning temperature and draw ratios were the same for both the processes. It is observed that while the yarn tenacities obtained with the two processes are similar, the yarn produced by the spin-drawn process gives a higher value for toughness. The resistance to cyclic fatigue is also higher for the spin-drawn yam. The birefringence, sonic modulus and density are higher for the yarns produced by the spin-draw process, signifying a higher densification of the structure in these yarns. Studies made on a thermo-mechanical analyzer reveal that while the maximum shrinkage values are similar, the yam obtained through the spin-draw process shows a higher shrinkage onset temperature as well as lower shrinkage at temperatures ranging between 120oC and 160oC. The results indicate that the tyre yam made by the spin-draw process is superior to the yarn made by the conventional process