Patent ID: 6652964
Filing Date: 2003-11-25
Classification: D01F,Y10T

Abstract:
A polyester fiber comprising a copolyester of terephthalic acid, trimethylene glycol and an ester-forming sulfonate compound represented by formula (X), the ester-forming sulfonate compound being copolymerized in a molar ratio in a range from 0.5 to 5 mole % based on the total molar content of all acid compounds forming the copolyester, wherein R1 and R2, which are the same or different from each other, represent a group selected from the group consisting of â€”COOH, â€”COOR, â€”OCOR, â€”(CH2)n OH, â€”(CH2)n[O(CH2)m]p OH and â€”CO[O(CH2)n]mOH (wherein R represents an alkyl group having from 1 to 10 carbon atoms, and n, m and p are each an integer of 1 or more), M represents a metal ion, NH4+ or a phosphonium group represented by P+R3R4R5R6 (wherein R3, R4, R5, and R6 are the same or different and are each a group selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and a hydroxyalkyl group), and Z represents a trivalent organic group, from 0.01 to 0.07 weight % based on the weight of the copolyester of a color inhibitor selected from the group consisting of cobalt acetate and cobalt formate and from 0.01 to 0.07 weight % based on the weight of the copolyester of a thermal stabilizer comprising a pentavalent or a trivalent phosphorous compound, wherein the fiber has a degree of yellow tinting b value of from âˆ’2 to 10 and a peak temperature of loss tangent of from 85 to 115Â° C.; and the relationship between modulus Q (g/d) and elastic recovery R (%) of the fiber satisfies the following formula (1):0.18&lE;Q/R&lE;0.45â€ƒâ€ƒ(1).