Multilayer structure and method for producing same

摘要

A multilayer structure, comprising: a layer of a resin composition (A); a layer of a saponified ethylene-vinyl acetate copolymer (B); and a layer of polyolefin (C) arranged on one side or both sides of those layers, wherein the resin composition (A) contains polyolefin (D), a saponified ethylene-vinyl acetate copolymer (E) and a saponified ethylene-vinyl acetate copolymer (F1) and/or an acid-modified ethylene-vinyl acetate copolymer (F2), the copolymer (E) has a mass ratio [E/(F1+F2)] of from 0.05 to 30, the polyolefin (D) has the copolymer (E) having an average particle diameter of from 0.1 to 1.8 μm dispersed in a matrix thereof, the layers of (A) and of (C) have thicknesses of from 50 to 1000 μm, and from 25 to 1000 μm, respectively, which enables provision of a multilayer structure having good gas barrier properties after retort processing and a good appearance.

主权项

1. A retort processed package, comprising:
a multilayer container and a content in the container, the multilayer container comprising: a layer of a resin composition (A); a layer of a saponified ethylene-vinyl acetate copolymer (B) having an ethylene content of from 20 to 65 mol % and having a degree of saponification of vinyl acetate units of 96% or more; and a layer of polyolefin (C) on a side of the layer of a resin composition (A) and the layer of a saponified ethylene-vinyl acetate copolymer (B), wherein the container comprises two of the layers of the resin composition (A), and the layer of the saponified ethylene-vinyl acetate copolymer (B) is between the layers of the resin composition (A), the resin composition (A) comprises a polyolefin (D), a saponified ethylene-vinyl acetate copolymer (E) having an ethylene content of from 20 to 65 mol % and having a degree of saponification of vinyl acetate units of 96% or more, and from 0.3 to 2.0 mass % of the resin composition (A) of at least one copolymer (F) selected from the group consisting of a saponified ethylene-vinyl acetate copolymer (F1) having an ethylene content of from 68 to 98 mol % and having a degree of saponification of vinyl acetate units of 20% or more and an acid-modified ethylene-vinyl acetate copolymer (F2) having an ethylene content of from 68 to 98 mol %, a mass ratio (E/F) of the saponified ethylene-vinyl acetate copolymer (E) to a total of the copolymer (F) is from 0.05 to 30, the saponified ethylene-vinyl acetate copolymer (E) is dispersed as particles with an average particle diameter of from 0.1 to 1.8 μm in a matrix of the resin composition polyolefin (D), the layer of the resin composition (A) has a thickness of from 50 to 1000 μm, the layer of the polyolefin (C) has a thickness of from 25 to 1000 μm, and the container has an oxygen transmission rate after 24 hours passed since retort processed for 30 minutes at 120° C. and 0.15 MPa of from 0.1 to 6 cc/m2·day·atm.