Bayer Materialscience, LLC

Bayer Polymers LLC

Thomas A J Gross

Rolf-Volker Meyer

Bruce D Lawrey

Segmented polyurethane/ureas useful for the production of spandex, particularly spandex fibers, are made from isocyanate-terminated prepolymers formed by reacting excess isocyanate with an isocyanate-reactive component satisfying specified compositional requirements in the presence of a catalyst which promotes linear polymerization but does not cause degradation of the polymer. Suitable catalysts include metal salts of organic fatty acids and/or of naphthenic acid. The isocyanate-reactive component includes at least 10 equivalent percent of a polyoxypropylene diol having a number average molecular weight of at least about 1500 Da and an average unsaturation level less than or equal to 0.03 meq/g and up to 90 equivalent percent of a polytetramethylene glycol having a number average molecular weight of at least 200 Da.

Prepolymer catalysts suitable for preparing spandex fibers

Segmented polyurethane/ureas useful in the production of spandex are produced by chain extending an isocyanate-terminated prepolymer with a diamine chain extender that includes: (1) from about 7 to 25 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine and (2) a linear diamine such as ethylene diamine in the presence of a solvent. The isocyanate-terminated prepolymer is produced by reacting a stoichiometric excess of an isocyanate with an isocyanate-reactive component that includes: (1) from about 10 to about 70 equivalent percent of a polyoxypropylene diol having a molecular weight in excess of 1500 Da and an average unsaturation level no greater than about 0.03 meq/g and (2) from about 30 to about 90 equivalent percent of a polytetramethylene ether glycol having a molecular weight of at least 600 Da.

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Wulfrath, Germany

Thomas A J Gross