Abstract

The structure and properties of lycra-viscose core-spun yarns made on ring- and air-jet spinning machines in relation to ribbon width, filament position and spinning speed have been studied. Under all experimental conditions, the air-jet spun core yarns are weaker, less extensible, hairier and have poor abrasion resistance than the conventional core yarns; however, the positioning of filament on the roving has a decisive effect on core yarn quality. The core yarns produced with centered adjustment of lycra filament, in general, display substantially higher strength and breaking extension, less bulk, less hairiness, and poor abrasion resistance and regularity and more imperfections regardless of the yarn structure. Furthermore, fine air-jet core yarns exhibit smaller helix diameter, more wrapper fibres and wraps/cm and larger helix angle than the coarse core yarns. Increase in spinning speed results in higher incidence of wrapper fibres; however, both wraps/cm and helix angle increase initially and decrease thereafter with increasing spinning speed.

Keywords:Air-jet spinning; Core-spun yarn; Lycra filament; Ribbon width; Wrapper fibres