HIGHLY ORIENTED UNDRAWN YARN OF POLYESTER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a highly oriented undrawn yarn of a polyester suppressed in the orientation by spinning and achieving improvement in productivity, to provide a method for stably and efficiently producing the highly oriented un drawn yarn of the polyester without causing problems in processes and further obtain the highly oriented undrawn yarn of the polyester excellent in drawing properties and processability of drawing and false twisting. SOLUTION: This highly oriented undrawn yarn of the polyester has >=25×110-3 and <=70×10-3 birefringence and the following characteristics: (1) the undrawn yarn has a sea-island structure composed of the polyester as the sea component and a polymer incompatible therewith and having higher elongation viscosity at 100 deg.C than that of the polyester as the island component in the cross section; (2) the total area of the island component is 0.5-5% based on the total cross section area of the yarn; and (3) the dispersed state of the respective island component is regulated to <=5 dispersion index (Mw/Mn).