Method of applying a coating to a steel plate

An application of a coating material containing a radically or ionically polymerizable monomer that can be changed into a high molecular compound by irradiation with ionizing radiations is provided to protect steel from corrosion and the adhesion of organic material. In this irradiation, the radiation doses are not more than 30 Mrad. The coating material is at least one kind of vehicle selected from the group consisting of a radically or ionically polymerizable monomer, polymer, copolymer, or compound of this monomer. They are, for example, styrene, acrylate, methacrylate, vinyl pyridine and their derivatives, acrylonitrile, acryl amide, and other vinyl compounds, etc. The absorption doses may be 30 or less Mrad, but preferably in the range of from 10 to 1 Mrad. Advantages are that the auxiliary heating can be performed below 1000C, and that hardening can be carried out below 500C. Furthermore, the irradiation time is shorter than 30 seconds; may kinds of vehicles can be used; and solvent is unnecessary. In one example, 15 parts of acryl amide, 40 parts of styrene and 45 parts of ethyl acrylate are copolymerized. This copolymer is dissolved into 100 parts of styrene and is mixed with 50 parts of rutile and 50 parts of yellow lead. The obtained vehicle is hardened with 10 Mrad. The coated film 30μ thick shows no defects due to weathering after 3 months. In another example, a mixture of 80 parts of unsaturated polyester and 20 parts of ethylene dimethacrylate gives 3H by irradiation with 6 Mrad in inert gas. (Iwakiri, K.)