| abstract |
A composite gas barrier film having a layer structure comprises a thermoplastic resin film laminated on at least one side of a film formed from polyglycolic acid containing at least 60 wt. % of a repeating unit represented by the following formula (1):wherein the polyglycolic acid film is a film formed from polyglycolic acid having a melt viscosity, eta* of 500 to 100,000 Pa.s as measured at a temperature of the melting point of the polymer +20° C. and a shear rate of 100/sec, a melting point Tm of at least 150° C., and a melt enthalpy, DELTAHm of at least 20 J/g. An adhesive layer is provided between the polyglycolic acid film and the thermoplastic resin film. The film has excellent oxygen gas barrier property and/or carbon dioxide gas barrier property. |