Patent ID: 7022874

Claim:
A process for the preparation of a polyisocyanate which contains one or more biuret groups by reacting a) an aliphatic or cycloaliphatic isocyanate containing two or more isocyanate groups (isocyanate (a)) with b) 0.5 to 20 mol % based on the isocyanate groups in (a) of a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretizing agent (b)) at from 100 to 250° C., which comprises carrying out the reaction in the presence c) from 0.01 to 2.0 mol % based on the isocyanate groups in (a) of a stabilizer (c) selected from the group consisting of urea, ammonia, biuret, ethylene urea, a urea derivative of the formula I in which R 1 , R 2 , R 3 and R 4 are hydrogen, C 1 to C 10 alkyl or C 6 to C 10 aryl, or a carboxamide of the formula II in which R 5 is C 1 to C 12 alkyl which is unsubstituted or in which 1, 2 or 3 hydrogen atoms are replaced by a radical