Plastic bottles and process for preparation thereof

A process for the preparation of coated plastic bottles which excel in both oxygen-barrier property and water resistance, which comprises coating at least one surface of a plastic bottle-forming parison, preform or sheet formed of a thermoplastic resin by melt molding with an aqueous latex of a copolymer consisting essentially of 99 to 70% by weight of vinylidene chloride and 1 to 30% by weight of at least one acrylic or methacrylic monomer and further including up to 100 parts by weight of at least one member selected from other ethylenically unsaturated monomers per 100 parts by weight of the total amount of said two monomers, said copolymer having an oxygen permeability constant of less than 9.times.10.sup.-14 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg as measured at a temperature of 20.degree. C. and a relative humidity of 100% and a water vapor permeability constant of less than 3.times.10.sup.13 g.multidot.cm/m.sup.2 .multidot.day as determined according to the method of JIS Z-0208, drying the coated parison, preform or sheet to form a coating layer, subjecting the so-formed coated structure to biaxially drawing blow molding or deep forming to introduce monoaxial or biaxial orientation in said plastic substrate, and then increasing the oxygen-barrier property and water resistance of the coated plastic bottle by subjecting the resultant bottle to aging at a temperature of 30.degree. to 120.degree. C. for 30 seconds to 7 days.