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