Influence of spinning parameters on core yarn sheath slippage and other properties

Filament-core yarns are produced to take advantage of both filament and staple fiber properties. They offer good strength and uniformity without sacrificing the staple fiber yam-like surface characteristics. However, a disadvantage of the core yarns is that the staple fiber sheath may slip along the filament when being pulled to pass over or when being rubbed by machine parts during further mechanical processes. In this investigation, two methods of testing core yarn sheath slipping resistance are employed to evaluate this core yarn property, using a universal fabric abrasion tester and a yarn abrasion tester. Filament tension applied during both ringframe and DREF-2 core yarn production has a highly significant effect on the sheath slipping resistance; a relatively high tension is advantageous for ring spinning, but otherwise for DREF-2 spinning. Twisting the filament before core yarn production can also alter the sheath slipping resistance of core yam produced by either of the two spinning systems, its effect depending on the direction and level of twist applied to the filament.