| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject fiber that is excellent in resistance to alkaline hydrolysis and is suitable for blending with cotton fibers by polymerizing a specific polyester polyol, a lower-molecular-weight diol and an organic diisocyanate. SOLUTION: (A) a polyester polyol with an average molecular weight of 500-5,000 in which 1-70 mol.%, preferably 10-50 mol.% of the polyol is a diol of the formula (R<1> is H, an alkyl or 2 or more carbon atoms; R<2> is an alkyl of 1 or more carbon atoms), (B) a low-molecular-weight diol with a molecular weight of <=500 and (C) an organic diisocyanate are polymerized to form a polyurethane and the resultant polyurethane is used to produce the objective fibers. In a preferred embodiment, the fiber strength retention is >=70% before and after the constant-length alkali treatment of the fiber in 60 g/l sodium hydroxide aqueous solution at 98 deg.C for 30 minutes and the stress retention is >=60% at 200% elongation before and after the alkali treatment. |
