Multilayer structure, and packaging material formed from the multilayer structure

Patent metadata

Field	Value
Publication number	US-11020945-B2
Application number	US-202016781268-A
Country	US
Kind code	B2
Filing date	Feb 4, 2020
Priority date	Mar 18, 2015
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A multilayer structure is provided, which includes a layer containing a saponified ethylene-vinyl ester copolymer, and a layer of a thermoplastic resin other than the saponified ethylene-vinyl ester copolymer provided on at least one side of the saponified ethylene-vinyl ester copolymer-containing layer with the intervention of an adhesive resin layer. An interface layer having a thickness (X) of 50 to 400 nm is present in an interface between the saponified ethylene-vinyl ester copolymer-containing layer and the adhesive resin layer. Alternatively, a viscosity increase rate in the interface between the saponified ethylene-vinyl ester copolymer-containing layer and the adhesive resin layer is 0.1% to 8%. Therefore, the multilayer structure has long-run durability, and is less liable to have poor appearance even if being produced by a multilayer coextrusion method.

First claim

The invention claimed is:

1. A multilayer structure comprising:
a layer containing a saponified ethylene-vinyl ester copolymer;
a layer of a thermoplastic resin other than the saponified ethylene-vinyl ester copolymer provided on at least one side of the saponified ethylene-vinyl ester copolymer-containing layer; and
an adhesive resin layer provided between the saponified ethylene-vinyl ester copolymer-containing layer and the thermoplastic resin layer;
wherein an interface layer having a thickness (X) of 50 to 400 nm is present in an interface between the saponified ethylene-vinyl ester copolymer-containing layer and the adhesive resin layer, and
wherein the adhesive resin layer has an absorbance ratio (α/β) of an absorbance (α) measured at around 1710 cm −1 and an absorbance (β) measured at around 1450 cm −1 in a range of from 0.005 to 0.4 analyzed by means of an infrared spectrometer (IR).

2. The multilayer structure according to claim 1 , wherein the saponified ethylene-vinyl ester copolymer is a mixture of two or more saponified ethylene-vinyl ester copolymers having different ethylene structural unit contents.

3. The multilayer structure according to claim 2 , wherein the two or more saponified ethylene-vinyl ester copolymers have a maximum ethylene structural unit content and a minimum ethylene structural unit content which are different from each other by a difference (ΔEt) of 10 to 25 mol %.

4. The multilayer structure according to claim 1 , wherein the saponified ethylene-vinyl ester copolymer-containing layer further contains a zinc salt of a higher fatty acid.

5. The multilayer structure according to claim 1 , wherein the saponified ethylene-vinyl ester copolymer-containing layer further contains 350 to 800 ppm of a zinc salt of a higher fatty acid based on an amount of the saponified ethylene-vinyl ester copolymer.

Assignees

• Mitsubishi Chem Corp

Inventors

• Komuro Ryohei

Classifications

• C08J2429/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• B32B27/34

  comprising polyamides · CPC title

• B32B21/08

  of synthetic resin · CPC title

• B32B27/10

  of paper or cardboard · CPC title

• B65D65/40

  Applications of laminates for particular packaging purposes {(B65D1/0215, B65D1/28, B65D3/22, B65D5/0281, B65D5/563, B65D9/30, B65D29/02, B65D31/02, B65D75/26, B65D77/2024, B65D81/1275, B65D81/3811, B65D81/3823, B65D81/3834, B65D81/3846, B65D81/3858, B65D81/3874, B65D81/3886, B65D81/3897 take precedence; laminates per se or laminated packages characterised by the composition or)} · CPC title