Patent ID: 9394631
Filing Date: 2016-07-19
CPC Classification: C08G,D01D,D01F,D03D,D04B,Y10T

Claim Text:
1. A core-sheath composite fiber comprising a core component comprising an easily alkaline elutable polyester with a main repeating unit constructed of ethylene terephthalate containing 2.0 to 5.5 mol % of an isophthalic acid component containing a metal sulfonate group relative to a total acid component and 3.0 to 6.0 mol % of an adipic acid component relative to the total acid component, and a sheath component comprising a polyamide, wherein the easily alkaline elutable polyester and the polyamide react in an ester-amide exchange reaction at an interface of the easily alkaline elutable polyester and the polyamide and a unit reaction rate of a terephthalic acid that caused the ester-amide exchange reaction is 0.0005 to 0.0025%·mm, wherein the unit reaction rate is calculated from Equation (1): where A is the unit reaction rate, T is the reaction rate (%) of the terephthalic acid that caused the ester-amide exchange reaction, and S is the surface area of the core of the fiber axis portion per 1 mm wherein the S is calculated from Equation (2): where (a) Core portion's circumference length (mm): X,