Patent ID: 8445622
Filing Date: 2013-05-21
Classification: C08G

Abstract:
1. 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 where R R Z is oxygen (O) or sulfur (S), X is oxygen (O), sulfur (S), imino (NH) or substituted imino (NR R where in the case of the compounds (S) the at least one of the radicals R 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.