Method for high-speed spinning of bicomponent fibers
Highly crimped, fully drawn bicomponent fibers, prepared by melt-spinning, followed by gas-flow quenching, heat treatment and high speed windup, are provided, as are fine-decitex and highly uniform polyester bicomponent fibers.
1 - 26 . (canceled)
27 . A process for preparing a bicomponent fiber comprising the steps of:
(a) providing poly(trimethylene terephthalate) and a polyester selected from the group consisting of poly(ethylene terephthalate) and a copolyester of poly(ethylene terephthalate) having different intrinsic viscosities;
(b) melt-spinning the two polyesters from a spinneret to form at least one bicomponent fiber having a cross-section selected from the group consisting of side-by-side and eccentric sheath-core;
(c) providing at least one flow of gas to at least one quench zone below the spinneret and accelerating the flow to a maximum velocity in the direction of fiber travel;
(d) passing the fiber through the quench zone;
(e) withdrawing the fiber at a withdrawal speed in the range of about: 820 to 4,000 meters per minute when co-current quench gas flow is used, and in the range of about 1,000 to 3,000 meters per minute when cross or radial quench gas flow is used; and
(f) winding up the fiber without drawing.
28 . The process of claim 27 further comprising, after step (f), the steps of:
(g) drawing; and
(h) heat-treating the fibers.
29 . The process of claim 28 , wherein the fibers have, after step (h), an after-heat-set crimp contraction value of at least about 30%.
30 . The process of claim 28 , wherein step (g) follows step (f) by less than about 35 days.