Evaluation of physical bulk of air-jet textured yarns

Abstract

A series of air-jet textured yarns has been prepared from two feed materials based on 3-level Box and Behnken design and the effect of process variables such as overfeed, air pressure and texturing speed on the textured yam bulk studied using package density and knitted fabric methods of bulk measurement. The physical bulk obtained from package density method with different winding tension has been correlated with knitted fabric specific volume obtained from the measured value of fabric thickness under different pressure. The fabric specific volume evaluated at and beyond 20 gf/cm² pressure during thickness measurement is found to correlate well with the physical bulk of textured yam using bobbin winder with the winding tension at and beyond 0.3 gf/tex and 0.6 gf/tex for drum and spindle driven winders respectively.