Method for production of a copolyester resin film laminated metal sheet

A method for producing a metal sheet or strip laminated with a biaxially oriented copolyester resin film comprising essentially of the steps of

• heating a metal sheet or strip having both sides covered with a double layer consisting of a lower layer of metallic chromium and an upper layer of hydrated chromium oxide to a temperature of Tm-50.degree. C. to Tm-4.degree. C. and
• laminating a 5-50 .mu.m thick biaxially oriented copolyester resin film having a melting temperature of T.sub.m, a density of 1.3500 to 1.4100 g/cc, and a planar orientation coefficient of 0.0668-0.1510 directly onto both sides of said covered metal sheet or strip with laminating rolls having a surface temperature of Tm-150.degree. to Tm-10.degree. C., and
• wherein Tm is 200.degree. C.-250.degree. C. and wherein the copolyester resin consists essentially of 75 to 99 mol % of polyethylene terephthalate and 1 to 25 mole % of a polyester resin which is produced by the esterification of at least one saturated polycarboxylic acid selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, succinic acid, azelaic acid, adipic acid, sebacic acid, diphenylcarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid and trimellitic acid anhydride with at least one saturated polyalcohol selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, propylene glycol, polytetramethylene glycol, trimethylene glycol, triethylene glycol, neopentyl glycol, 1,4-cyclohexane dimethanol, trimethylol propane and pentaerythritol.