Process for preparing liquid, storage-stable organic isocyanates having carbodiimide and/or uretonimine groups and having low colour number

Abstract

The invention relates to a process for preparing liquid, storage-stable isocyanate mixtures having carbodiimide (CD) and/or uretonimine (UI) groups or prepolymers derived therefrom, wherein (i) in a first step, a starting isocyanate which is an organic isocyanate or a mixture of two or more organic isocyanates is partly carbodiimidized with a catalyst K of the formula cyclo-C4H6P(O)R, where the substituent R is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical, and then (ii) in a second step, the carbodiimidization reaction is stopped at a temperature of ≤80° C. by adding a stopper, the stopper used being an organic silane S of the general formula HnSiX4-n, where n is a natural number in the range from 1 to 3, where X is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical.

Dependencies are inferred from the claim text.