Process for the preparation of granular urethane-urea polymers

Claim 1

A suspension process for the preparation of essentially linear polyurethane-urea granules comprising the steps of: a. adding to a water solution of from about 2% to about 20% by weight of a water-soluble inert suspending agent 1. a solution comprising an organic solvent which does not contain a reactive hydrogen, and a. an organic diisocyanate selected from the group consisting of cycloaliphatic diisocyanate, aliphatic diisocyanate and aromatic diisocyanate, b. a water immiscible polyol comprising not more than up to about 30 mole percent based on total hydroxy group content of a crosslinking component which has at least three hydroxyl groups per molecule. c. a catalyst not favoring the water-isocyanate reaction over the polyol-isocyanate reaction, wherein the mole fraction of said organic diisocyanate with respect to said organic diisocyanate and polyol is from about 0.5 to about 1.00 and the amount of water is sufficient to form the continuous reaction phase; b. heating the reaction mixture of step (a) to a temperature of from about 50° to 150° C. with stirring sufficient to form a suspension and distilling a constant boiling distillate of said organic solvent and water; c. terminating the distillation of step (b) when substantially no organic solvent remains in said distillate and substantially no unreacted isocyanate remains in the reaction mixture; and d. separating the solid polyurethane-urea granules formed in step (b).