Patent ID: 6376698
Filing Date: 2002-04-23
Classification: C08G

Abstract:
A prepolymer having an NCO value of 5 to 11.5% by weight, said prepolymer being obtained by reacting:(1) a stoichiometrically excessive amount of (i) a diphenylmethane diisocyanate comprising at least 95% by weight of 4,4â€²-diphenylmethane diisocyanate; or (ii) a diphenylmethane diisocyanate variant, derived from a polyisocyanate composition having 4,4â€²-diphenylmethane diisocyanate in an amount of at least 95% by weight of the polyisocyanate composition, said variant being selected from the group consisting of liquid products obtained by introducing uretonimine, and/or carbodiimide groups into said polyisocyanate composition, and/or products obtained by reacting said polyisocyanate composition with one or more polyols, or mixtures thereof; with (2) a polyol composition comprising: (a) from 85 to 100% by weight of at least one polyoxyalkylene polyol containing oxyethylene moieties and having an average nominal hydroxyl functionality of from 2 to 6, an average hydroxyl equivalent weight of from 1000 to 3000 and an average oxyethylene content of from 50 to 85% by weight; and (b) from 0 to 15% by weight of one or more polyols other than said at least one polyoxyalkylene polyol.