AIR-JET TEXTURING OF SPUN COTTON YARNS FOR IMPROVED COMFORT .2. TEXTURABILITY OF CARDED SPUN YARNS COMPARED TO COMBED SPUN YARNS

We have studied the importance of yarn structural variants such as fiber packing density, fiber fineness and length distribution, mean fiber extent, and migration parameters in deciding the bulking potential of a spun yarn structure with air-jet texturing. Three variants of carded yarns, combed yarns, and yarns made from combed sliver which is again carded in both 100% spun and composite spun forms with three different twist levels show that fiber-to-fiber distance and frictional hindrance may have a significant influence on the relative local velocities of the fibers in the turbulent air stream, which would affect the texturing behavior. We have observed that spun yarns with uniform fiber length distribution, higher fiber extent, and more fiber parallelization, such as combed yarns, have less bulk during texturing. Yarns with higher packing and migration have higher frictional hindrance with less fiber-to-fiber distance. They are therefore subjected to reduced flow asymmetry and produce yarns with reduced bulk.