Process for the preparation of allophanate, allophanate and low viscosity composition comprising the allophanate

摘要

Method of preparing allophanate of one or more identical or different isocyanates or of a mixture of different allophanates, by reacting one or more isocyanates with at least one monoalcohol with an ether or polyether function, characterized in that the reaction is carried out in presence of a compound containing bismuth as a catalyst and a metal compound as a cocatalyst, chosen from among the alkali metal or alkaline earth metal carboxylates, with a metal compound content between 0.5 and 100 ppm in relation to the amount of monoalcohol.