Polypropylene Oxide Laminate for Heat-Stable Moisture Barrier Packaging

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Solution Overview

Problem

Existing laminated polypropylene films with transparent vapor-deposited layers, such as Alox or SiOx, face issues with insufficient heat resistance, water vapor barrier properties, and potential cracking under high-temperature conditions, making them unsuitable for applications requiring processing and moisture resistance.

Innovation Solution

A laminate comprising a polypropylene-based resin film with an inorganic oxide layer, characterized by a water vapor transmission rate of less than 3.0 g/m2/day, peel strength of 0.7 N/15 mm, and stress difference SF145° C.−SF121° C.≤2.50 MPa, ensuring excellent water vapor barrier and adhesion, suitable for high-temperature environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent vapor-deposited layer (Alox or SiOx) is used instead of Al vapor deposition, then transparency and recyclability are improved, but heat resistance and water vapor barrier property are insufficient at high temperatures

Engineering Contradiction:
ImprovetransparencyVSAvoidwater vapor barrier property
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention uses a composite inorganic oxide layer containing multiple oxide components (at least one from Groups 13-16 and at least one from Groups 1-12) to achieve both transparency and high-temperature water vapor barrier properties. This composite approach allows the layer to maintain optical clarity while providing sufficient barrier performance at elevated temperatures up to 150°C or higher.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters including the thickness of the inorganic oxide layer (50-200 nm), the atomic ratios of oxide components, and the deposition conditions to achieve the desired balance between transparency and water vapor barrier property. By controlling these parameters, the layer maintains low water vapor transmission rates even at high temperatures while remaining transparent.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the inorganic oxide layer is made thicker to improve water vapor barrier property, then barrier performance is enhanced, but cracks and delamination are likely to occur

Engineering Contradiction:
Improvewater vapor barrier propertyVSAvoidadhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention optimizes the thickness of the inorganic oxide layer to a specific range (50-200 nm) that provides sufficient water vapor barrier performance without causing cracks or delamination. This precise thickness control, combined with optimized oxide composition ratios, ensures the layer remains adherent and crack-free while achieving low water vapor transmission rates.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite inorganic oxide structure with multiple oxide components creates a more flexible and adherent layer that can accommodate thermal expansion differences between the film and substrate. This composite approach prevents cracking and delamination even at optimized thicknesses that provide excellent barrier performance.

Inventive Principle:
Principle #40Composite materials

3Temperature

If the polypropylene film base material has high heat resistance, then shrinkage under high temperature is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveheat resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention selects polypropylene resins with specific melting points (160-170°C) and crystallinity ranges (40-60%) to achieve adequate heat resistance without requiring complex manufacturing processes. By optimizing these material parameters, the film maintains dimensional stability at high temperatures up to 150°C while using standard polypropylene processing equipment and methods.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The laminate maintains a balance between water vapor barrier properties and adhesion, reducing moisture influence, and withstands high-temperature processing without cracking or delamination, enhancing recyclability and reliability.

Implementation Method 1

there is a trend toward replacing the conventional Al vapor-deposited layer with a transparent vapor-deposited layer such as aluminum oxide (hereinafter, which may be referred to as Alox) or silicon oxide (hereinafter, which may be referred to as SiOx)

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentUS12577650B2Laminate, packaging material, and packaging body
Publication Date: 2026.03.17 TORAY INDUSTRIES INC

AI summary

A laminate having a polypropylene resin film and an inorganic oxide layer, wherein the laminate is characterized in that the water vapor transmission rate is less than 3.0 g/m2/day, the peel strength of the inorganic oxide layer is 0.7 N/15 mm or more, and when the stress at 121° C. in the main orientation axis direction as measured by thermomechanical analysis (TMA) is denoted by SF121° C. and the stress at 145° C. in the main orientation axis direction is denoted by SF145° C., said laminate satisfies SF145° C.−SF121° C.≤2.50 MPa. The present invention provides a laminate that is suitable for use in applications in which processing and use in a high-temperature environment are required and there is a need to reduce the effects of moisture.