| 摘要 |
Provided is an elastic polyurethane fiber comprising a polyurethane obtained by copolymerizing a polymer diol (A), an organic diisocyanate (B) and a chain extender (C); said polymer diol (A) that constitutes the polyurethane being a polyester diol and/or polyesterpolycarbonate diol having an average molecular weight of 1,000 to 6,000, and satisfying the following condition (I); wherein the total number of carbon atoms means the number of the carbon atoms contained in the polymer diol and excluding those contained in the ester bonds and carbonate bonds thereof; the diol units that constitute said polymer diol containing branched diols in an amount of at least 10 molt; said polyurethane constituting said elastic fiber satisfying the following conditions (II) and (III) 45% ? long chain hard segment content ? 75% (II) wherein the long chain hard segment content means the ratio of the amount of long chain hard segments containing at least 3 repeating units from (B) and (C) combinedly, to the amount of total hard sognents eomprising eomponents (B) and (C) and, linked thereto via urethane bonds, the terminal diol eomponent of (A), the amounts of said three eomponents being determined on the three eomponents taken out by alcoholysis of eomponent (A) of said polyurethane with an alkali-methanol solution; Retention of long chain hard segment ? 85% (III) content after heat melting wherein the retention of long chain hard segment content after heat melting means the ratio between the contents of long chain hard segments after and before melt-kneading at 230.degree.C for 60 minutes of said polyurethane constituting said elastic fiber. The fiber is obtained by melt spinning and has excellent resistance to chlorine and light and excellent elastic recovery and resistance to heat and hot water and being dyeable together with polyester fibers under hightemperature, high-pressure conditions.
|
