Multilayer Gas Barrier Structure for Solvent-Resistant Lamination
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Solution Overview
Problem
Conventional multilayer structures with 8 or more layers delaminate when exposed to organic solvents, compromising gas barrier and flexural resistance.
Innovation Solution
A multilayer structure comprising a gas barrier layer with ethylene-vinyl alcohol copolymer and a thermoplastic resin with functional groups, and a polyurethane layer, with specific content ratios and lamination configurations, enhancing solvent resistance and maintaining gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer structure with 8 or more layers is used to improve gas barrier properties and flexural resistance, then gas barrier properties and flexural resistance are improved, but delamination occurs when exposed to organic solvents
Solution Approach 1:
The invention changes the chemical composition parameters of the resin layers, specifically incorporating a polyurethane layer containing isocyanate groups that react with hydroxyl groups in the EVOH layer. This chemical modification creates covalent bonds between layers, fundamentally changing the interlayer bonding mechanism from physical adhesion to chemical bonding, thereby preventing delamination in solvent environments while maintaining the multilayer gas barrier structure.
Solution Approach 2:
The invention uses composite materials by combining EVOH (ethylene-vinyl alcohol copolymer) with polyurethane in a multilayer structure. The specific composite formulation includes a polyurethane layer with isocyanate groups that chemically react with the EVOH layer, creating a bonded composite structure that resists delamination in organic solvent environments while maintaining gas barrier properties.
2Reliability
If a multilayer structure with 8 or more layers is used to improve gas barrier properties and flexural resistance, then gas barrier properties and flexural resistance are improved, but flexural resistance deteriorates due to delamination
Solution Approach 1:
The invention modifies the chemical composition by introducing isocyanate-containing polyurethane layers that form chemical bonds with EVOH layers. This parameter change in interlayer bonding strength prevents delamination under flexural stress, thereby maintaining flexural resistance while preserving the gas barrier functionality of the multilayer structure.
Solution Approach 2:
The invention employs a composite material system where polyurethane layers with isocyanate groups are bonded to EVOH layers through chemical reactions. This composite structure provides both the gas barrier properties of EVOH and the flexural resistance of polyurethane, with strong interlayer bonding preventing delamination during flexing.
3Adaptability or versatility
If conventional multilayer structures are exposed to organic solvents for coloring, then coloring can be achieved, but delamination occurs compromising the structure
Solution Approach 1:
The invention changes the chemical bonding parameters between layers by incorporating isocyanate groups in the polyurethane layer that form covalent bonds with hydroxyl groups in EVOH. This chemical modification enables the structure to withstand organic solvent exposure during coloring processes without delamination, maintaining structural integrity while allowing coloring functionality.
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 structure achieves superior solvent resistance and maintains gas barrier properties even when exposed to organic solvents, with improved flexural resistance and delamination prevention.
Implementation Method 1
a thermoplastic resin (a2) having a functional group capable of reacting with the ethylene-vinyl alcohol copolymer (a1)
Data Source
AI summary
The present disclosure provides a multilayer structure having a gas barrier layer and a polyurethane layer; a molded product having such a multilayer structure; and a method for producing the molded product.