Retort Stand-Up Pouch With Polyamide–EVOH Barrier Laminate

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Solution Overview

Problem

Stand-up pouches with vapor-deposited inorganic oxide coatings suffer from poor flexing resistance and gas barrier impairment, leading to reduced barrier properties after retort processing, and existing solutions are costly and inefficient.

Innovation Solution

A laminate structure comprising a base film, a polyamide resin layer, and an EVOH layer, with the polyamide resin layer adjoining the EVOH layer, enhances gas barrier recovery and stability post-retort processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vapor-deposited coating of inorganic oxide is used as film base, then gas barrier properties are improved, but flexing resistance deteriorates and pinholes form

Engineering Contradiction:

Improvegas barrier propertiesVSAvoidflexing resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite film structure combining a polyolefin resin layer with an EVOH layer. The polyolefin provides flexibility and mechanical strength, while the EVOH layer provides the gas barrier function. This composite approach allows the film to maintain both good flexing resistance and high gas barrier properties without the pinhole formation issues associated with vapor-deposited inorganic oxide films.

Inventive Principle:

Principle #40Composite materials

2Reliability

If gas-barrier coating film is disposed separately on vapor-deposited inorganic oxide surface, then gas barrier properties are improved, but production efficiency deteriorates and cost increases

Engineering Contradiction:

Improvegas barrier propertiesVSAvoidproduction efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent combines the gas barrier function and the base film function into a single integrated EVOH layer structure. The EVOH layer itself serves as both the structural base and the gas barrier layer, eliminating the need for separate vapor-deposited inorganic oxide coating and separate gas-barrier coating film application processes. This merging of functions improves production efficiency and reduces costs while maintaining effective gas barrier properties.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If polyolefin films are used as inner layers, then self-supporting properties are improved, but gas barrier properties deteriorate

Engineering Contradiction:

Improveself-supporting propertiesVSAvoidgas barrier properties

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent segments the film structure into distinct functional layers: a polyolefin resin layer that provides self-supporting properties and mechanical strength, and a separate EVOH layer that provides the gas barrier function. By dividing the film into specialized segments, each layer can optimize its specific function without compromising the other, allowing the inner layer to maintain both self-supporting properties and gas barrier properties.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3287391B1Stand-up pouch for retort

Publication Date: 2025.10.15 MITSUBISHI CHEM CORP

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AI summary

An object of the present invention is to provide a stand-up pouch for retort which has a high rate of gas barrier property recovery after retort processing and can stably retain high gas barrier properties. The stand-up pouch for retort of the invention comprises a laminate which comprises a base film and, disposed over one surface of the base film, a polyamide resin layer, a saponified ethylene-vinyl ester copolymer layer, and a heat-sealing resin layer, wherein the polyamide resin layer adjoins the saponified ethylene-vinyl ester copolymer layer.