Coating resin composition

A coating composition curable by radiation in the air is provided. The composition is composed of 95 to 50 parts (by wt.) of a solution (solid content 5 to 40%) of polyvinylbutyral (DP 250 to 2000, butyral content 40 to 75% by mole) in a vinyl monomer and 5 to 50 parts of a solution (solid content 90 to 40%) of acrylic or methacrylic ester of a di- or poly-epoxy compound as a cross-linking agent in a vinyl monomer. Upon irradiation with electron beams (1 to 9 Mrad) the composition cures to give a coating exhibiting excellent resistance to weather, corrosion, alkali and abrasion, as well as a high flexibility and superior adhesion property. In one example, 70 parts of a solution of polyvinylbutyral (DP 250 to 500, butyral content 60% by mol) (30 parts) in Bu acrylate(70 parts) was mixed with 30 parts of a solution (solid content 70%) of an adduct of Epikote 834 (Shell Chem. Corp.) (252 parts) with dimethylaminoethyl methacrylate (15 parts) plus methacrylic acid (86 parts) in Me methacrylate, and then with 20 parts of titanium oxide. A zinc-plated iron was coated with the composition. Irradiation with electron beams (4 Mrad) gave a coating of excellent workability, weather resistance and luster. (Kaichi, S.)