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

US10633330B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Hans-Detlef Arntz · Overath, DE
• Torsten Hagen · Essen, DE
• Ernst Felske · Neuss, DE

Key dates

• Filing date: Sep 7, 2017
• Grant date: Apr 28, 2020
• Expiry date: Sep 7, 2037

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G18/8019
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.