| abstract |
The present invention is directed to a liquid, storage-stable isocyanate prepolymer having an isocyanate group content of from 10 to 30% by weight, prepared by reacting:n i) a polyamine containing at least two aromatically bound primary amino groups prepared by hydrolyzing an isocyanate compound having an isocyanate group content of from 0.5 to 40% by weight, with ii) an isocyanate mixture comprisingn a) from 50 to 100% by weight of diphenylmethane diisocyanates of which from 3 to 50% by weight consist of the 2,2′- and 2,4′-isomers, and b) the balance being polyphenylpolymethylene polyisocyanates, with the proviso that if said mixture comprises from 95 to 100% by weight of diphenylmethane diisocyanate, at least 15% by weight of said diisocyanate consisting of the 2,2′- and 2,4′- isomers. |