Method for producing polyisocyanates

A method for making oligomeric isocyanates comprising reacting a diisocyanate in the presence of a catalyst, wherein the catalyst consists of a saline compound prepared from an anion of a compound selected from the group consisting of pyrrole, substituted pyrrole, carbocyclically annellated derivatives of pyrrole, heterocyclically annellated derivatives of pyrrole, pyrazole, imidazole, substituted pyrazole, substituted imidazole, carbocyclically annellated derivatives of pyrazole, heterocyclically annellated derivatives of pyrazole, heterocyclically annellated derivatives of imidazole, 1,2,3- or 1,2,4-triazole, carbocyclically annellated species of 1,2,4-triazole, heterocyclically annellated species of 1,2,3- or 1,2,4-triazole, and mixtures thereof and a cation selected from alkali, alkaline-earth and/or monovalent ammonium cations and/or phosphonium cations of formula (5)

• wherein
• E represents nitrogen or phosphorus and R1, R2, R3 and R4 independently of one another represent the same or different radicals selected from a saturated aliphatic or cycloaliphatic, or an optionally substituted aromatic or araliphatic radical with up to 18 carbon atoms respectively;
• and
• said anion is formed prior to reacting said dilsocyanate with said catalyst.