Process for the production of oligomeric polyisocyanates and their use in the production of polyurethane plastics
First Claim
1. A process for the production of an oligomeric polyisocyanate which comprises dimerizing and/or trimerizing a portion of the isocyanate groups of an organic polyisocyanate in the presence of a tertiary phosphine or a peralkylated phosphorus acid triamide as catalyst and terminating the dimerization and/or trimerization reaction at the desired degree of oligomerization by adding a sulfonyl isocyanate as the catalyst poison.
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Abstract
The present invention relates to a process for the production of oligomeric polyisocyanates by the dimerization or trimerization of a portion of the isocyanate groups in organic polyisocyanates in the presence of tertiary phosphines or in the presence of a peralkylated phosphorus acid triamides as catalyst, followed by termination of the dimerization and/or trimerization reaction at the required degree of oligomerization by the addition of a catalyst poison, characterized in that a sulfonyl isocyanate is used as the catalyst poison.
The present invention also relates to the use of the oligomeric polyisocyanates obtained by this process, optionally in admixture with unreacted starting polyisocyanate or optionally blocked by blocking agents for isocyanate groups, as the polyisocyanate component in the production of polyurethane plastics.
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20 Claims
- 1. A process for the production of an oligomeric polyisocyanate which comprises dimerizing and/or trimerizing a portion of the isocyanate groups of an organic polyisocyanate in the presence of a tertiary phosphine or a peralkylated phosphorus acid triamide as catalyst and terminating the dimerization and/or trimerization reaction at the desired degree of oligomerization by adding a sulfonyl isocyanate as the catalyst poison.
Specification