as a catalyst under certain circumstances the hydroxylic group containing ethylenic monomers include 2 hydroxyethyl acrylate 2 hydroxypropyl acrylate 2 hydroxyethyl methacrylate 2 hydroxypropyl methacrylate 2 4 dihydroxy 4 39 vinyl benzophenone n 2 hydroxyethyl acrylamide n 2 hydroxyethyl methacrylamide and the like the film forming polymers according to the present invention are obtained by copolymerizing the above described monomers with other ethylenic monomers by the known methods the other ethylenic monomers include styrene alpha methylstyrene acrylic esters e g methyl acrylate ethyl acrylate butyl acrylate or 2 ethylhexyl acrylate methacrylic esters e g methyl methacrylate ethyl methacrylate butyl methacrylate isobutyl methacrylate and p butyl methacrylate and the like the amide group containing ethylenic monomers used for the preparation of the film forming polymers are used in a quantity of 5 to 40 by weight preferably 8 to 30 by weight if they are used in a quantity less than 5 by weight a disadvantage occurs in that flake like metallic pigments have poor orientation and thus a surface appearance is poor while if they are used in a quantity exceeding 40 by weight the obtained film has poor water resistance the acid group containing ethylenic monomers are used in a quantity of 3 to 15 by weight preferably 5 to 13 by weight if they are used in a quantity less than 3 by weight an aqueous dispersibility is deteriorated while if they are used.