JPH0262375B

PURPOSE:To improve strength, thermoformability and gas barrier properties by preventing heat deterioration, by interposing thermoplastic resin, whose melt apparent viscosity at the temperature of 190 deg.C and a shear rate of 100sec has been specified, between resin, A, B as a heat barrier. CONSTITUTION:Thermoplastic resin layers 3, 3' whose melt apparent viscosity is low are interposed among a vinylidene chloride series resin layer 1 and high- melting-extrusion-temperature thermoplastic resin layers 2 2' as heat barriers. Vinylidene chloride monopolymer or copolymer is used for the vinylidene chloride series layer 1. Propylene series resin or polyester resin or polycarbonate resin is used for the coextrusion thermoplastic resin layers 2, 2' whose melt apparent viscosity is more than 9,000 poise. The resin which is extrudable within such a low temperature sphere of 190 deg.C-220 deg.C at the melt apparent viscosity of less than 9,000 poise in the presence of the thermoplastic resin layers 3, 3' is used. The resin layers 3, 3' act upon as the heat barries and heat deterioration of the vinylidene chloride series resin is prevented as the same is not exposed directly to a high temperature at the time of coextrusion.