UV-curing printing inks

A printing ink curable by UV radiation and comprising

• A. from 0 to 50 percent by weight of a pigment conventionally used in printing inks;
• B. from 0.5 to 15 percent by weight of a mixture of benzophenone and Michler's ketone;
• C. from 40 to 85 percent by weight of at least one polymerizable olefinically unsaturated compound which has an average molecular weight of from 250 to 4000 and which contains at least one group of the formula:
• ##STR5## wherein R is a hydrogen atoms or a methyl group and at least one urethane group, which has been manufactured from aliphatic or cycloaliphatic diisocyanates or polyisocyanates and at least one hydroxyl-containing acrylic or methacrylic compound selected from the group consisting of ethylene glycol monoacrylate or monomethacrylate, 1,2- or 1,3-propanediol monoacrylate or monomethacrylate, 1,4-butanediol monoacrylate or monomethacrylate and 1,6-hexanediol monoacrylate or monomethacrylate and
• D. from 10 to 25 percent by weight of at least one compound which is liquid at 50.degree. C and which is obtained by reacting a diglycidyl ether of an aliphatic diol, triol or tetrol, containing from 2 to 8 carbon atoms with acrylic acid or methacrylic acid used in an amount of at least one mole per epoxide group in the diglycidyl ether and optionally thereafter esterifying or etherifying the reaction product at the free hydroxyl group or groups thereof;
• the polymerizable olefinically unsaturated compound (s) (C) and the compound (s) (B) which is liquid at 50.degree. C being such that when in admixture they form a mixture having a vapor pressure of less than 1 mm Hg at 100.degree. C and a viscosity greater than 1 poise at 30.degree. C and containing substantially no fatty oils of fatty acids having more than 6 carbon atoms.