Liquid isocyanate prepolymers

Claim 1

A liquid, storage-stable isocyanate prepolymer having an isocyanate group content of from 3 to 30% by weight, prepared by reacting (i) a diisocyanate corresponding to the formula ##STR11## which may be present in admixture with 0 to 40% by weight, based on the total mixture, of diisocyanates corresponding to the formula ##STR12## and optionally with 0 to 30% by weight, based on the total mixture, of other diisocyanatodiphenylmethane isomers which may be substituted; wherein two of the radicals R 1 , R 2 and R 3 represent hydrogen and one of the radicals R 1 , R 2 and R 3 represents a methyl group; with (ii) a polyamine of the structure ##STR13## where R represents an m-valent residue obtained by the removal of m-functional groups from a compound having m-functional groups and having a molecular weight of from 76 to about 10,000, X represents --O--, ##STR14## R 1 represents hydrogen or an inert substituent, R 2 represents hydrogen, a C 1 to C 5 alkyl group or a phenyl group, n is 1 or 2, and m is an integer of from 2 to 8.