Patent ID: 6485665
Filing Date: 2002-11-26
Classification: D01F,Y10S

Abstract:
A method for producing polyurethane elastomer fibers, comprising the steps of(a) producing a segmented polyurethane polymer based on i) a macro-diol with a molecular weight of approximately 500 to 10,000, ii) at least one diisocyanate belonging to the class consisting of aliphatic, cyclo-aliphatic and aliphatic-cycloaliphatic diisocyanates, and iii) a chain extender with at least two molecular groups belonging to the class consisting of hydroxy and amino groups, the polymer having a molar excess of isocyanate groups of at least approximately 0.2% over the combined total of hydroxy and amino groups from the macro-diol and chain extender, said percentage of 0.2% being in relation to the combined total of hydroxy and amino groups, wherein macro-diol, chain extender and diisocyanate, with the optional addition of a catalyst, are brought together to react with each other, essentially in the absence of a solvent; (b) melt-extruding the polyurethane polymer to form a fiber, wherein steps (a) and (b) are carried out under temperature conditions and within a time interval where essentially no allophanate will be formed; (c) subjecting the fiber to a post-treatment under temperature conditions and within a time interval in which cross-linking of the polyurethane polymer will occur through the formation of allophanate; and (d) exposing the extruded fiber to high-energy radiation to effect an at least partial cross-linking of the polyurethane elastomer.