Process for preparing low-viscosity allophanates containing actinically curable groups

Abstract From the Canadian patent

The present invention provides a process for preparing radiation-curing allophanates having residual monomer contents of less than 0.5% by weight and an NCO content of less than 1 % by weight wherein (A) compounds containing isocyanate groups (B) hydroxy-functional compounds which contain groups which react with polymerization, with ethylenically unsaturated compounds on exposure to actinic radiation (radiation-curing groups) and (C) optionally further compounds containing NCO-reactive groups also optionally in the presence of a catalyst are used to form NCO-group-containing urethanes having radiation-curing groups which are subsequently reacted, without further addition of compounds …