Abstract

A process for the production of solid polyisocyanates stabilized by a polymer coating and showing retarded reactivity comprising reacting(1) one or more solid polyisocyanates in particulate form, said polyisocyanates having melting points above 30° C., and(2) from 0.1 to 25 equivalent percent of amine per isocyanate equivalent of an organic compound having a molecular weight of from 32 to 6000, said organic compound being selected from the group consisting of(a) di- or higher functional compounds containing 2 or more aliphatically-bound primary and/or secondary amino groups,(b) compounds containing one or more terminal --CO--, --NH--, --NH2 -- groups,(c) hydrazines, and(d) mixtures thereofsaid reaction being conducted at a temperature below the melting temperature of said solid polyisocyanate, and being conducted in the presence of(3) a liquid medium selected from the group consisting of(a) organic compounds containing one or more hydroxy groups and having molecular weights of from 62 to 6000,(b) organic compounds containing 2 or more aromatically-bound amino groups and having molecular weights of from 108 to 6000,(c) organic compounds containing 2 or more aliphatically-bound amino groups and having molecular weights of from 400 to 6000,(d) plasticizers,(e) water, and(f) mixtures thereofto form a suspension of polyadduct-coated, stabilized polyisocyanate in the liquid medium.