Actinic radiation-curable formulations from the reaction product of organic isocyanate, poly(alkylene oxide) polyol and an unsaturated addition-polymerizable monomeric compound having a single isocyanate-reactive hydrogen group

A coating composition comprising

• (A) at least one unsaturated urethane resin comprising the reaction product of
• (i) at least one organic isocyanate compound having at least two isocyanate groups;
• (ii) at least one poly(alkylene oxide) polyol, said polyol having from 1 to 9 carbon atoms in the alkylene group separating each pair of oxygen atoms, and
• (iii) at least one unsaturated addition-polymerizable monomeric compound having a single isocyanate-reactive active hydrogen group;
• there being present an excess of isocyanate compound with respect to the hydroxyl groups of said poly(alkylene oxide) polyol;
• said unsaturated addition-polymerizable monomeric compound having a single isocyanate-reactive active hydrogen group being present in an amount sufficient to provide at least one molar equivalent of active hydrogen group with respect to isocyanate reactivity;
• B) a reactive diluent system comprising at least one unsaturated addition-polymerizable monomeric compound which is copolymerizable with said unsaturated urethane resin;
• the amount of unsaturated urethane resin being in the range from about 30 to about 90 weight percent, based on total weight of unsaturated urethane resin and reactive diluent system;
• (C) At least one aromatic ketone or aromatic aldehyde photosensitizer which promotes photopolymerization through bimolecular photochemical reactions of the energy donor type or hydrogen abstraction type;
• and
• (D) At least one aromatic ketone photoinitiator which generates a radical pair by way of unimolecular homolysis resulting from photoexcitation.