Resin coating composition and method for its production

A covering resin composition, such as a coating material, which exhibits excellent properties with respect to various synthetic resin sheets, films and moldings, or an adhesive resin composition. The composition is produced by mixing a carboxylated chlorinated polyolefin resin, prepared by the graft copolymerization of a polyolefin with an alpha , beta -unsaturated carboxylic acid and/or anhydride thereof followed by chlorination, with a chlorinated polyolefin resin prepared by oxidatively treating a polyolefin with at least one member selected from among air, oxygen and ozone during the chlorination of the polyolefin, conducting the graft copolymerization of the obtained resin mixture with a monomer having an ethylenically unsaturated bond in its molecule and another monomer having both an ethylenically unsaturated bond and a hydroxyl group in its molecule, and compounding the obtained graft copolymer with an isocyanate compound or an alkyl-etherified amino-resin as a curing agent.