Radiation curable compositons based on unsaturated polyesters and compounds having at least two vinyl ether groups

A method of coating comprising:

• (A) applying to a substrate a layer of a radiation curable composition containing an unsaturated polyester having a plurality of maleate and/or fumarate groups and a non-polymerized, cocurable vinyl ether component free radically reactive with said unsaturation of said polyester and selected from the group consisting of:
• (a) vinyl ether compounds containing an average of at least two reactive vinyl ether groups per molecule and (b) a vinyl ether containing group bonded to the polyester, the composition being free of components that would destabilize the composition under coating application conditions, whereby polymerization of the vinyl ether component is substantially avoided until cocured with the unsaturated polyester when initiated by exposure to radiation;
• (B) providing the curable composition in liquid form to wet the substrate;
• and
• (C) curing said composition through its thickness to a tack-free state by means of crosslinking the polyester component using the vinyl ether groups as the primary crosslinking agent, the curing being effected by exposing said film to ionizing radiation and/or ultraviolet light.