| abstract |
A process for producing polyisocyanates containing one or more biuret groups, by reacting a) an aliphatic or cycloaliphatic isocyanate with several isocyanate groups (isocyanate a) with b) a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretting agent b) at reaction temperature of 100 to 250 DEG C, said process being characterized in that the reaction is conducted in the presence of c) a stabiliser (c) in which there are catalytic quantities of urea, ammonia, biuret, a urea derivative of the formula (I), in which R<1>, R<2>, R<3> and R<4> are hydrogen, C1-C10 alkyl or C5-C10 aryl, or a carbonic acid amide of formula (II) in which R<5> is C1-C12 alkyl group, in which 1, 2 or 3 hydrogen atoms may be replaced by a (III) radical. |