Process for the production of polyisocyanates with biuret structures

Abstract

Polyisocyanates with biuret structures are produced at temperatures above 250.degree. C. More specifically, an excess of a diisocyanate having aliphatically and/or cycloaliphatically bound isocyanate groups is reacted with a diamine containing aliphatically and/or cycloaliphatically bound amino groups at temperatures above 250.degree. C. for relatively brief periods of time. Water and/or polyvalent alcohols may optionally be included in the reaction mixture. The polyisocyanates with biuret structures produced by this process are characterized by good color, good dilutability with covalent solvents and comparatively low viscosity.

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