Structural and characteristic variations in viscose ring- and air-jet spun yarns as a consequence of draw frame speed and its preparatory process

Abstract

The influence of high draw frame speed and its preparatory on the structure and properties of viscose ring- and air-jet spun yarns has been studied. The data indicate insignificant differences in the tensile and regularity characteristics of the yarns produced with different card drafts and the yarns made with high draw frame speed display higher strength, higher breaking extension and better regularity than the yarns made with lower draw frame speed. Furthermore, a lower second nozzle pressure is needed to reduce rigidity of air-jet yarns to acceptable limits. When compared with ring-spun yarns, air-jet yarns have significantly smaller helix angle, but display higher packing density. Of the various process variables, card draft and second nozzle pressure markedly affect mean fibre extent, helix angle and packing density, whereas draw frame speed affects each of the parameters studied in a non-distinguishable manner.