| 摘要 |
PROBLEM TO BE SOLVED: To obtain a bonded fibrous structure having a good bonded state, lowering less in bonding strength even at high temperature and having soft feeling by using a low-melting copolyester made from an acid component consisting mainly of terephthalic acid and adipic acid in a specified molar ratio and a diol component consisting mainly of ethylene glycol and 1,4- butanediol in a specified molar ratio and having a specified crystalline melting point, a specified intrinsic viscosity and a specified b value of color. SOLUTION: The molar ratio between the acid components, terephthalic acid/adipic acid ratio is 90/10 to 60/40, and the molar ratio between the diol components, ethylene glycol/1,4-butanediol is 80/20 to 30/70. The copolyester has a crystalline melting point of 100-190 deg.C, an intrinsic visocity of 0.45 or above, and a b value of color of 10 or below. The polycondensation catalyst used in the production of the copolyester comprises 1×10<-4> to 5×10<-4> mol of an antimony compound (e.g. antimony trichloride) and 0.05×10<-4> to 1×10<-4> mol of a titanium compound (e.g. tetrabutyl titanate) per mol of the acid component.
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