US 12,071,712 B2
Eccentric core-sheath composite fiber and combined filament yarn
Norio Suzuki, Mishima (JP); Hideki Morioka, Mishima (JP); and Masato Masuda, Mishima (JP)
Assigned to Toray Industries, Inc., Tokyo (JP)
Appl. No. 16/469,700
Filed by Toray Industries, Inc., Tokyo (JP)
PCT Filed Dec. 12, 2017, PCT No. PCT/JP2017/044477
§ 371(c)(1), (2) Date Jun. 14, 2019,
PCT Pub. No. WO2018/110523, PCT Pub. Date Jun. 21, 2018.
Claims priority of application No. 2016-242514 (JP), filed on Dec. 14, 2016; and application No. 2017-106632 (JP), filed on May 30, 2017.
Prior Publication US 2020/0087820 A1, Mar. 19, 2020
Int. Cl. D01F 8/14 (2006.01); D02G 3/04 (2006.01)
CPC D01F 8/14 (2013.01) [D02G 3/04 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An eccentric core-sheath composite fiber comprising two kinds of polymers that are ingredient A and ingredient B, the eccentric core-sheath composite fiber having a fineness unevenness (U %) of 1.5% or less, and a single-filament fineness of 0.8 dtex or less,
wherein the ingredient B is poly(ethylene terephthalate), and
in a cross-section of the composite fiber:
the ingredient A is a polyester selected from PBT, 3GT, PET and coPET, and is covered entirely by the ingredient B;
a ratio S/D of a minimum thickness S of a thickness of the ingredient B that covers the ingredient A, to a fiber diameter D is 0.01 to 0.1;
a portion where the ingredient B has a thickness up to 1.05 times the minimum thickness S has a peripheral length of at least one-third of an entire circumferential length of the fiber; and
a fiber cross-section satisfies expression (1), wherein IFR is a radius of curvature of an interface between ingredient A and ingredient B in the fiber cross-section and R is a value obtained by dividing the fiber diameter D by 2,
(IFR/R)≥1 expression (1);
wherein the fiber has improved feeling and graininess.