Multilayer structure and method for producing same

Disclosed is a multilayer structure which comprises a layer of a resin composition (A) and a layer of a saponified ethylene-vinyl acetate copolymer (B) that has an ethylene content of 20-65% by mole and a saponification degree of the vinyl acetate unit of 96% or more, while having a layer or layers of a polyolefin (C) arranged on one side or both sides of the above-mentioned layers. The resin composition (A) contains: a polyolefin (D); a saponified ethylene-vinyl acetate copolymer (E) that has an ethylene content of 20-65% by mole and a saponification degree of the vinyl acetate unit of 96% or more; and a saponified ethylene-vinyl acetate copolymer (F1) that has an ethylene content of 68-98% by mole and a saponification degree of the vinyl acetate unit of 20% or more and/or an acid-modified ethylene-vinyl acetate copolymer (F2) that has an ethylene content of 68-98% by mole. The mass ratio of the saponified ethylene-vinyl acetate copolymer (E) to the total of the saponified ethylene-vinyl acetate copolymer (F1) and the acid-modified ethylene-vinyl acetate copolymer (F2), namely [E/(F1 + F2)] is 0.05-30. The saponified ethylene-vinyl acetate copolymer (E) having an average particle diameter of 0.1-1.8 μm is dispersed in a matrix of the polyolefin (D). The layer of the resin composition (A) has a thickness of 50-1,000 μm, and each layer of the polyolefin (C) has a thickness of 25-1,000 μm. Consequently, the multilayer structure has good gas barrier properties after retort processing, while having a beautiful appearance.