Patent ID: 7371807

Claim:
A blocked biuret group-containing polyisocyanate composition having a blocked isocyanate functionality of at least 4 prepared by a process comprising A) reacting a polyisocyanate adduct which a) is prepared from an aliphatic and/or cycloaliphatic diisocyanate, b) has an isocyanate functionality of at least 2.5 and c) which contains isocyanurate groups, with a biuretizing agent to incorporate biuret groups into said polyisocyanate, and B) reacting the biuret-containing polyisocyanate with a blocking agent of the formula: wherein R 1 , R 2 , R 3 and R 4 may be the same or different and represent a moiety selected from the group consisting of hydrogen, C 1 -C 6 -alkyl and C 3 -C 6 -cycloalkyl, R 5 represents a moiety selected from the group consisting of C 1 -C 10 -alkyl and C 3 -C 10 -cycloalkyl, and B is a group according to one of the following structural formulas wherein each occurrence of R 6 , R 7 , and R 8 may be the same or different and represent a moiety selected from the group consisting of C 1 -C 6 -alkyl and C 3 -C 6 -cycloalkyl and R 9 is a moiety selected from the group consisting of hydrogen, C 1 -C 6 -alkyl and C 3 -C 6 -cycloalkyl.