INFLUENCE OF SPINNING PARAMETERS ON CORE YARN SHEATH SLIPPAGE AND OTHER PROPERTIES

Filament-core yarns are produced to take advantage of both filament an d staple fiber properties. They offer good strength and uniformity wit hout sacrificing the staple fiber yam-like surface characteristics. Ho wever, a disadvantage of the core yarns is that the staple fiber sheat h may slip along the filament when being pulled to pass over or when b eing rubbed by machine parts during further mechanical processes. In t his investigation, two methods of testing core yarn sheath slipping re sistance are employed to evaluate this core yarn property, using a uni versal fabric abrasion tester and a yarn abrasion tester. Filament ten sion applied during both ringframe and DREF-2 core yarn production has a highly significant effect on the sheath slipping resistance; a rela tively high tension is advantageous for ring spinning, but otherwise f or 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 direct ion and level of twist applied to the filament.