Patent No. U.S. 7,816,418 B2
PPG Industries has been granted a patent for a radiation-curable coating composition comprised of 50%-80% by weight a radiation-curable compound, the improvement comprised of including in the coating composition 1%-5% by weight a free acid, wherein the free acid is selected from tannic acid, phosphoric acid, gallic acid and/or citric acid; 1%-10% by weight of a halogenated polyolefin; 1%-3% by weight of a photoinitiator; and a phosphate ester acrylate; so as to improve the adhesion of the coating composition to both metal and plastic substrates; the percentages by weight being based on weight of total resin solids in the composition.