False-twist textured yarn and polyester highly oriented undrawn fiber

摘要

PROBLEM TO BE SOLVED: To provide the subject fiber having specified wide angle X-ray diffraction pattern and birefringence, enabling draw-false twist texturing at a draw ratio comparable to conventional process, exhibiting small change with time and having high twist tension in draw false-twisting process. ;SOLUTION: The objective highly oriented undrawn polyester fiber exhibits diffraction peaks attributable to polyester crystal by wide angle X-ray diffraction and has a birefringence of 0.015-0.050 which is comparable to or lower than that of conventional highly oriented underawn polyester yarn(POY). The fiber can be produced e.g. by using a polyester as a sheath component and a polymer having a temperature dependency of extension viscosity higher than that of the sheath component as a core component and melt-spinning the polymers at a spinning speed of 4,000-9,000m/min or thereabout.;COPYRIGHT: (C)1997,JPO