| 摘要 |
<p>The invention relates to thermoplastic polyurethanes obtainable by reacting a polyol composition (A) which consists essentially of a polyester-polyol (A-1) having a crystallization enthalpy of at most 70 J/g and a number-average molecular weight of from 1000 to 5000 and a polyether-polyol (A-2) having a number-average molecular weight of from 500 to 2500, and in which the average number, f, of the functional hydroxyl groups existing therein falls between 2.006 and 2.100, an organic diisocyanate (B), and a chain extender (C), at a ratio that satisfies the following formula: <MATH> wherein a indicates the number of moles of all polyols constituting the polyol composition (A), b indicates the number of moles of the organic diisocyanate (B), and c indicates the number of moles of the chain extender (C); to elastic fibers comprising them; and to a method for producing polyurethane elastic fibers by melt-spinning the thermoplastic polyurethane. The thermoplastic polyurethanes and the polyurethane elastic fibers comprising them have good properties of spinning stability, heat resistance, hot water resistance, elastic recovery, elongation and homogeneousness of fiber.</p> |
