| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject fiber capable of being processed into a covered elastic yarn whose breakage can be reduced, even when inversely wound at a low temperature, and which can be wound into a cheese wherein the unwinding and the loosing breakage of the covered elastic yarn are reduced, by using as a diol component a specific diol containing specific oligomers in an amount of specified value or less. SOLUTION: This polyurethaneurea elastic fiber contains as a diol component a copolyalkylene ether diol [the number-average mol.wt. (Mn) is preferably 1,000 to 40,000] which contains cyclic oligomers comprising nine or less repeating units in an amount of <=1.5 wt.%, preferably <=1.0 wt.% and has methyl side chains. The rapid deterioration of the extension recovery, especially the extension recovery rate, of a covered elastic yarn using the polyurethaneurea elastic fiber due to the lowering of temperature can be improved, and the inverse winding of the covered elastic yarn on a cheese due to adhesion is reduced.
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