Patent ID: 8106140

Claim:
A process for preparing radiation-curing allophanates having a residual monomer content of less than 0.5% by weight and an NCO content of less than 1% by weight, the process comprising: 1) preparing NCO-group-containing urethanes having radiation-curing groups by reacting: A) one or more compounds containing isocyanate groups, B) a mixture containing 100 mol % of a mixture of hydroxyethyl acrylate and hydroxypropyl acrylate, in which 20-40 mol %, of hydroxyethyl acrylate is included, C) optionally further, non-radiation-curing compounds containing NCO-reactive groups D) optionally in the presence of a catalyst; and 2) reacting the NCO-group-containing urethanes simultaneously or subsequently, without further addition of compounds containing isocyanate groups, in the presence of: E) an allophanatization catalyst and, F) optionally, a tertiary amine; the ratio of NCO groups of the compounds from A) to the OH groups of the compounds from B) and, where used, C) being 1.45:1.0 to 1.1:1.0.