Patent ID: 8604097

Claim:
A radiation-curing binder comprising allophanate groups, wherein said radiation-curing binder is prepared by a process comprising reacting A) a compound comprising at least one uretdione group and optionally comprising free NCO groups; with B) an OH-functional compound which comprises at least one group selected from the group consisting of vinyl ethers, acrylates, and methacrylates which polymerize with ethylenically unsaturated compounds on exposure to actinic radiation; and C) optionally an NCO-reactive compound other than B); in the presence of D) a catalyst comprising at least one zinc compound; at a temperature of less than or equal to 130° C. wherein said at least one uretdione group of the compound of component A) undergoes ring opening to form at least one allophanate group; if present, all free NCO groups of the compound of component A) are reacted with component B) and optionally component C) in the presence of a catalyst capable of catalyzing the reaction of NCO groups with NCO-reactive groups; and the OH groups of the OH-functional compound of component B) are present in a molar excess to the uretdione and free NCO groups of the compound of component A), with the proviso that any hydroxyl groups which remain following the reaction of A) with B) are reacted in a subsequent reaction step.