Process for the production of polyisocyanates containing isocyanurate groups
First Claim
1. A process for the production of polyisocyanates containing isocyanurate groups and having a monomeric diisocyanate content, based on solids, of at most 0.7%, by weight, comprising (1) partially trimerizing the isocyanate groups in organic diisocyanates in the presence of catalysts which accelerate the trimerizing reaction of isocyanate groups and (2) terminating the trimerizing reaction at the desired degree of trimerization by thermally decomposing the catalyst used or by deactivating the catalyst used by adding a catalyst poison, wherein(a) Mannich bases are used as catalysts and(b) the trimerizing reaction is carried out in the presence of inert solvents at a temperature below 60°
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Abstract
This invention relates to a new process for the production, in inert organic solvents, of physiologically compatible polyisocyanates containing isocyanurate groups which have a monomeric diisocyanate content, based on solids, of at most 0.7%, by weight. The process uses Mannich bases as the trimerizing catalyst at temperatures below 60° C and the reaction is terminated at the desired degree of trimerization by thermally decomposing the catalyst or by deactivating with a catalyst poison.
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Citations
10 Claims
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1. A process for the production of polyisocyanates containing isocyanurate groups and having a monomeric diisocyanate content, based on solids, of at most 0.7%, by weight, comprising (1) partially trimerizing the isocyanate groups in organic diisocyanates in the presence of catalysts which accelerate the trimerizing reaction of isocyanate groups and (2) terminating the trimerizing reaction at the desired degree of trimerization by thermally decomposing the catalyst used or by deactivating the catalyst used by adding a catalyst poison, wherein
(a) Mannich bases are used as catalysts and (b) the trimerizing reaction is carried out in the presence of inert solvents at a temperature below 60°
Specification