PROCESS FOR THE PREPARATION OF SUSPECTED SUSPENSIONS OF SOLID POLYISOCYANATES, STABILIZED BY POLYMER COATING, endowed with delayed reactivity in polyols and / or polyamines with aromatic amino groups, such suspensions and their application

摘要

The present invention is directed to a process for the production of suspensions of finely-divided polyisocyanates which are obtainable by the surface reaction with from 0.1 to 25 equivalent percent of reactive group per NCO of stabilizers in relatively high molecular weight polyols and/or relatively high molecular weight polyamines having molecular weights from 400 to 6,000 optionally with addition of lower molecular weight polyols and/or aromatic amines having molecular weights of from 60 to 399, which are characterized in that unreacted quantities of stabilizers in the suspension are subsequently partially or completely deactivated by addition of substances having an acylating and/or neutralizing and/or alkylating effect and/or adsorbing effect as "deactivators". In particular, mono- and/or polyisocyanates are used as "deactivators". Deactivated suspensions obtainable in this way do not exhibit rising thickening temperatures during the production of polyurethanes, in particular in large-volume shaped articles. The present invention also relates to deactivated suspensions obtainable by the present process and to the use thereof for polyurethane production.