METHOD FOR THE PRODUCTION OF STABILIZED POLYISOCYANATES, STABILIZED POLYISOCYANATES OF RETARDED REACTIVITY AND THEIR USE FOR THE PRODUCTION OF POLYURETHANE.

摘要

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 DEG 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 thereof said 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 thereof to form a suspension of polyadduct-coated, stabilized polyisocyanate in the liquid medium.