| abstract |
A process for the preparation of polyisocyanates which contain one or more biuret groups, by reactingn a) an aliphatic or cycloaliphatic isocyanate containing two or more isocyanate groups (isocyanate a) with b) a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretizing agent b)n nat from 100 to 250° C., which comprises carrying out the reaction in the presencen c) of a stabilizer (c) which constitutes a catalytic amount of urea, ammonia, biuret, a urea derivative of the formula I n in which R 1 , R 2 , R 3 and R 4 are hydrogen, C 1 to C 10 alkyl or C 5 to C 10 aryl, or a carboxamide of the formula II n 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 |