1. Field of the Invention
The present invention relates to polyurethane having high resistance to degradation by chlorine and by atmospheric fumes. More particularly it relates to spandex containing particular combinations of additives.
2. Discussion of Background Art
A wide variety of phenolic compounds have been used as additives in attempts to stabilize organic compounds against degradation. For example, German Published Patent Application DE19630904 discloses phenolic compounds as additives for diisocyanates, German Published Patent Application DE2503050 discloses additives for polyolefins, Japanese Published Patent Application JP-01-193362 discloses additives for polyurethane, and U.S. Pat. Nos. 4,548,975 and 3,553,290 and Japanese Published Patent Application JP50-004387 disclose phenolic additive stabilizers for spandex. U.S. Pat. Nos. 5,663,128, 6,046,263, 4,891,391, and 5,478,875 and European Published Patent Application EP481533 also disclose additives for organic materials. U.S. Pat. Nos. 4,340,527 and 5,626,960 disclose inorganic additives for spandex.
However, further improvement in the resistance of polyurethane, and in particular spandex, to environmental degradation is still needed.