PROCESS FOR THE PRODUCTION OF STABILIZED POLYISOCYANATES, STABILIZED ISOCYANATES OF RETARDED REACTIVITY AND THEIR USE IN THE PRODUCTION OF POLYURETHANES

摘要

A PROCESS FOR THE PRODUCTION OF STABILIZEDPOLYISOCYANATES, STABILIZED ISOCYANATES OFRETARDED REACTIVITY AND THEIR USE INTHE PRODUCTION OF POLYURETHANESABSTRACT OF THE DISCLOSUREThe present invention relates to a process forthe production of solid polyisocyanates of retardedreactivity stabilized by surface modification byreacting solid, finely divided polyisocyanates, andparticularly dimeric tolylene diisocyanate, dimericdiphenylmethane diisocyanate and 3,3'-diisocyanato-4,4'-dimethyl-N,N'-diphenyl urea, with acyclic, mono- orbicyclic compounds having an amidine or guanidinestructure and which do not contain any hydrogen atomsreactive to isocyanates at room temperature in aquantity of from 0.1 to 25 equivalent percent of"amidine" or "guanidine" per isocyanate equivalent. Thereaction may be carried out directly in a liquid mediumselected from the group consisting of(i) organic compounds containing one or morehydroxy groups having molecular weights of from62 to 6000,(ii) organic compounds containing two or morearomatically-bound amino groups and havingmolecular weights of from 108 to 6000,(iii) organic compounds containing two or morealiphatically-bound amino groups and havingmolecular weights of from 400 to 6000,(iv) plasticizers,(v) water,(vi) mixtures thereof, and(vii) mixtures of any one or more of (d)(i) through(d)(vi) with an apolar or slightly polarsolvent,to form a suspension of polyadduct-coated, stabilizedpolyisocyanates in the liquid medium.