Patent attributes
Thermoplastic polyether polyurethane polymers are disclosed which are mixed with a crosslinking agent to achieve long run times in a melt spinning process to make elastic fibers. The crosslinking agent is preferably a polyether or polyester polyol reacted with a diisocyanate. A melt spinning process is also disclosed using a polyether polyurethane with a crosslinking agent. Long melt spinning run times can be achieved without experiencing excessive pressure buildup in the spinneret and fiber breakage. The thermoplastic polyether polyurethane polymers are made by reacting: (1) a blend of two or more hydroxyl terminated intermediates wherein one intermediate is a polyether intermediate and has a higher number average molecular weight than the other said polyether intermediates, and wherein the weighted average number average molecular weight of said blend is greater than 1200 Daltons; (2) at least one polyisocyanate; and (3) at least one hydroxyl terminated chain extender. Melt spun fibers disclosed have excellent dye pickup, bleach resistance, and color fastness. The melt spun fibers can be dyed with polyester fibers and retain excellent physical properties.
