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.