Polyisocyanates with biuret structure blocked with diisopropyl amine

摘要

Production of blocked polyisocyanates comprises (A) reacting polyisocyanates with biuretization agents optionally in presence of catalysts to give in the blocked end-product 5-45 equivalent % of biuret groups based on the total of free and blocked NCO groups; (B) optionally converting the free NCO groups using NCO-reactive compounds and/or catalysts; and (C) blocking >=95 mol. % of the remaining free NCO groups with a (cyclo)aliphatic amine. Production of blocked polyisocyanates comprises (A) reacting polyisocyanates with biuretization agents optionally in the presence of a catalyst to give in the blocked end-product 5-45 equivalent % of biuret groups of formula (I) based on the total of all free and blocked NCO groups; (B) optionally further converting the free NCO groups with the aid of isocyanate-reactive compounds and/or catalysts; and, finally, (C) blocking the remaining free NCO groups to an extent of >=95 mol.% with an amine of formula R 1>R 2>NH where R 1> and R 2> = 1-12C aliphatic or cycloaliphatic alkyl. [Image].