Process for producing stretched multilayer polyester bottle

Abstract

A process for producing a stretched multilayer polyester bottle which comprises axially stretching a bottomed multilayer preform comprised of an inside and an outside polyester surface layer and an interlayer of a gas-barrier resin provided therebetween optionally through an adhesive under conditions which induce molecular orientation of the polyester and simultaneously stretching it circumferentially by blowing. The multilayer preform is produced by coating a solution or emulsion of an ethylene-vinyl alcohol copolymer on one surface of a primary preform of the polyester molded in advance, drying the coated preform at a temperature at which no whitening owing to the crystallization of the polyester occurs to thereby form a thin but continuous film of the ethylene-vinyl alcohol polymer on the primary preform, mounting the coated pre-form on an injection mold, and injection the polyester onto the coated layer to form the inside or outside surface layer of the polyester. This process enables the ethylene-vinyl alcohol copolymer to be interposed as the interlayer of the stretched polyester bottle in a thickness which does not hamper the stretching operation but is sufficient to ensure its gas-barrier property.