Patent ID: 8445622

Claim:
A process for preparing polyisocyanates (P) by catalytic oligomerization of isocyanates (D), which comprises a) reacting at least one isocyanate (D) under suitable reaction conditions in the presence of at least one compound (K) which catalyzes the conversion of the isocyanate into the desired polyisocyanate and, optionally, in the presence of at least one alcohol (A) and, optionally, at least one solvent (L), b) adding to the reaction mixture at least one compound (S) which is able to deactivate the catalyst (K) when the desired conversion has been reached, and c) separating the unreacted isocyanate (D) from the resulting reaction mixture, wherein the compound (S) has the formula where R 1 and R 2 are each, independently of one another, hydrogen or C 1 -C 20 -alkyl, C 6 -C 12 -aryl or C 5 -C 12 -cycloalkyl which may optionally be substituted by aryl, alkyl, aryloxy, alkyloxy, heteroatoms and/or heterocycles, where R 1 ≠H when X═O or S, and R 1 and R 2 may together with the group X—(CO)—NH also form a 5- to 12-membered ring in which R 1 and R 2 together form an optionally substituted divalent C 2 -C 9 -alkylene radical which can also be part of an arylene or cycloalkylene radical, Z is oxygen (O) or sulfur (S), X is oxygen (O), sulfur (S), imino (NH) or substituted imino (NR 3 ) and R 3 is C 1 -C 4 -alkyl, where in the case of the compounds (S) the at least one of the radicals R 1 and R 2 has a group which is reactive toward isocyanat, wherein the catalyst (K) is at least one catalyst selected from the group consisting of N,N,N,N-tetramethylammonium hydroxide, N,N,N,N-tetraethylammonium hydroxide, N,N,N,N-tetra-n-butylammonium hydroxide, N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium hydroxide, N,N,N-trimethyl-N-(2-hydroxypropyl)ammonium hydroxide, N,N,N-trimethyl-N-benzylammonium hydroxide, N-(2-hydroxypropyl)-N,N,N-trimethylammonium 2-ethylhexanoate, N-(2-hydroxypropyl)-N,N,N-trimethylammonium 2-formate, hexamethyldisilazane, heptamethyldisilazane, hexaethyldisilazane, 1,3-diethyl-1,1,3,3-tetramethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane and 1,3-diphenyl-1,1,3,3-tetramethyldisilazane.