Patent ID: 6136435
Filing Date: 2000-10-24
Classification: D01F,Y10T

Abstract:
A polyester filament yarn having an improved winding performance, produced by melt-spinning a mixture of a polyester resin with particles of a filament elongation-enhancing agent in an amount of 0.5 to 4.0% based on the weight of the polyester resin, and by taking up the melt-spun polyester filament yarn at a speed of 2500 to 8000 m/minute, to form a polyester filament yarn comprising a plurality of filaments each comprising a matrix consisting of the polyester resin and the filament elongation-enhancing agent particles dispersed in the polyester resin matrix,said polyester filament yarn exhibiting an increase (I) in residual elongation of 50% or more, determined in accordance with the equation:I(%)=(EI.sub.b /EL.sub.o -1).times.100wherein I represents the increase in residual elongation in % of the polyester filament yarn, EI.sub.b represents a residual elongation in % of the polyester filament yarn, and EL.sub.o represents a residual elongation in % of a comparative polyester filament yarn produced by the same procedures as those for the polyester filament yarn except that no filament elongation-enhancing agent is contained in the comparative polyester filament yarn andcharacterized in that said filament elongation-enhancing agent particles contained in the polyester filaments satisfy the requirements (a), (b) and (c):(a) the filament elongation-enhancing agent particles have a thermal deformation temperature (T) in the range of from 105 to 130.degree. C.;(b) provided that the polyester filaments have a non-hollow circular cross-section, the distribution density of the filament elongation-enhancing agent particles in the circular cross-section of the polyester filament is maximized in an annular area between two concentric circles around the center of the circular cross-section, the radiuses of which two concentric circles correspond to 1/3 and 2/3 of the radius of the circular cross-section of the polyester filaments, respectively; and(c) the number (N) of the filament elongation-enhancing agent particles appearing on the peripheral surfaces of the polyester filament is 15 particles/100 .mu.m.sup.2 of less.