Patent ID: 6641765
Filing Date: 2003-11-04
Classification: D01D,D01F,D02G,Y10T

Abstract:
A method of preparing a polyester multifilament yarn, which comprises the steps of:(A) melt-spinning a solid-phase polymerized polyester chip, composed of 90 mol % or more of ethylene terephthalate units as the recurring unit and having an intrinsic viscosity of 1.05 to 1.13, through a spinneret at a temperature ranging from 290 to 298Â° C. to form a molten spun yarn, (B) rapid-cooling and solidifying the spun yarn by passing it through a solidification zone, (C) withdrawing the solidified yarn at such a rate that an undrawn yarn having a birefringence of 0.06 to 0.09 and a density of 1.360 to 1.375 is formed, and (D) hot-drawing the yarn to a total draw ratio of 1.5 to 2.5; so as for said yarn to have (1) a unit filament thickness of 2.5 to 3.5 denier, (2) an intrinsic viscosity of 0.94 to 1.00, (3) a DEG(diethylene glycol) content of 0.65 to 0.9 weight %, (4) a CEG(carboxyl end group) content of 23 eq./106 g or less, (5) a tenacity of 7.5 to 8.5 g/d, (6) an elongation of 13.0 to 16.0%, (7) a shrinkage of 4.0 to 7.0%, and (8) a silk factor (tenacity(g/d)Ã—{square root over (e)}longation at break) of at least 27.