A novel binder resin which attains good adhesion to various substrates such as polyolefin resins, vinyl chloride resins, polycarbonate resins, polyethylene terephthalate resins, acrylonitrile/butadiene/styrene resins, and nylon resins even by low-temperature baking and has excellent solubility in solvent. Namely, a chlorinated propylene random copolymer produced by subjecting a propylene random copolymer which is obtained by copolymerizing propylene with other alpha-olefins by using a metallocene catalyst as the polymerization catalyst and which has a melting point (Tm) of less than 115.degree. C. as determined with a differential scanning calorimeter (DSC) to thermally kneaded preferably at a temperature ranging from the melting point of the copolymer to 350.degree. C. and chlorination successively.