Co-injection molded multilayer structure and method for producing same

Abstract

There is provided a co-injection molded multilayer structure comprising a barrier layer and outer layers laminated to contact with the barrier layer on its both sides, wherein the barrier layer is made of a resin composition (X) comprising an ethylene-vinyl alcohol copolymer (A) and an alkali metal salt (B) of a higher fatty acid, having a melting point of 250° C. or lower; the ethylene-vinyl alcohol copolymer (A) has an ethylene unit content of 20 to 60 mol % and a saponification degree of 90% or more, and a content of the alkali metal salt (B) in the barrier layer is 50 to 1500 ppm in terms of metal atoms; and the outer layers are made of a resin composition (Y) comprising an unmodified high-density polyethylene (F) and a maleic anhydride-modified polyethylene (G), and a maleic anhydride modification rate relative to the whole resin composition (Y) is 0.005 to 0.1 wt %. This co-injection molded multilayer structure has excellent adhesiveness, so that its oxygen barrier performance can be maintained even after being subjected to an impact due to falling or the like.