POLYURETHANE DISPERSIONS FOR SEALANTS

摘要

An isocyanate-terminated prepolymer having an isocyanate group content of about 2 to 7% by weight is provided. The prepolymer comprises the reactio n product of a) at least one polyether diol having a number average molecular weight of 3000 to 5000; b) at least one active-hydrogen containing material having a number average molecular weight of 200 to 700 and containing two or three hydroxyl groups and optionally one carboxy group; c) at least one hydroxyalkane carboxylic acid having a number average molecular weight of le ss than about 200; d) optionally, a polyether monol having a number average molecular weight between 400-3,000; e) optionally, a polyether triol having a number average molecular weight of 3,000 to 9,000; and f) an aliphatic and/o r cycloaliphatic diisocyanate.