Process for the production of polyisocyanates which contain carbodiimide groups and which are stable in storage
AssigneeBayer Aktiengesellschaft
InventorsWalter Schafer, Kuno Wagner, Hans-Dieter Block
Life of this patent
Estimating the term…
Abstract
The instant invention relates to a process for producing stable equilibrium mixtures of carbodiimides, uretone imines and organic isocyanates and storage-stable solutions of carbodiimides and uretone imines in polyisocyanates which are free from carbodiimide groups. Either the carbodiimide, or the uretone imine, or both, may contain isocyanate groups. The invention relates to the process for the preparation of these products by so-called heterogeneous catalysis and the use of these products for the production of polyurethane resins.
Claims10
A process for preparing a storage stable, catalyst-free, equilibrium mixture of an organic carbodiimide, an organic uretoneimine and an organic isocyanate comprising the steps:
- (a) contacting an organic mono- and/or polyisocyanate with a high molecular weight carbodiimidization catalyst which is insoluble in organic isocyanate and which comprises a high molecular weight, insoluble organic matrix and a low molecular weight carbodiimidization catalyst bound to the matrix via covalent bonds, and
- (b) removing said high molecular weight catalyst when the desired degree of carbodiimidization has been reached.
Dependencies are inferred from the claim text.