SPANDEX FIBER USING ETHYLENE DIAMENE/1,2-DIAMINOPROPANE AS CHAIN EXTENDER AND PROCESS FOR MAKING SAME

摘要

The invention provides spandex having improved hysteresis and a method for making such spandex. The spandex of the invention comprises the polyurethaneurea reaction product of: (a) poly(tetramethylene ether) glycol; (b) 1-isocyanato-4-[(4- isocyanatophenyl)methyl]benzene wherein the mole ratio of diisocyanate to glycol is from about 1.52 to about 2.04; and (c) a mixture of chain extenders comprising: from about 35 to about 55 mole percent ethylene diamine; and from about 45 to about 65 mole percent 1,2-propanediamine.