Adhesive Resin Layer Transparency in Multilayer Structures
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Solution Overview
Problem
Conventional multilayer structures with thermoplastic and gas barrier resin layers face challenges in achieving high transparency due to interface roughness between the gas barrier and adhesive resin layers, and existing adhesive resin compositions often compromise on adhesion when trying to enhance transparency.
Innovation Solution
Incorporating a fatty acid zinc salt (B) in the adhesive resin layer composition, specifically in a proportion of 40 to 250 ppm on a metal basis, which contains a polyolefin resin with carboxyl or acid anhydride groups, to suppress interface roughness and ensure adhesion between the thermoplastic and gas barrier resin layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive resin layer is provided between the thermoplastic resin layer and the gas barrier resin layer to ensure adhesion, then adhesion between layers is improved, but interface roughness increases which deteriorates transparency
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive resin layer by incorporating specific functional groups (carboxyl groups, acid anhydride groups, or hydroxyl groups) and controlling the proportion of higher fatty acid metal salt to 100 ppm or less on a metal basis. This parameter optimization reduces interface roughness while maintaining adhesion, thereby improving transparency without sacrificing bonding strength.
Solution Approach 2:
The invention creates a composite adhesive resin composition by combining polyolefin resin with specific functional groups (carboxyl, acid anhydride, or hydroxyl) and higher fatty acid metal salts in controlled amounts. This composite material achieves both good adhesion to the gas barrier resin layer and reduced interface roughness for improved transparency.
2Strength
If the proportion of higher fatty acid metal salt in the adhesive resin layer is increased to improve adhesion, then adhesion force is improved, but transparency deteriorates due to increased interface roughness
Solution Approach 1:
The invention optimizes the concentration parameter of higher fatty acid metal salt by limiting it to 100 ppm or less on a metal basis. This precise parameter control achieves the optimal balance between adhesion force and interface smoothness, ensuring both bonding strength and transparency are maintained at high levels.
Data Source
AI summary
A multilayer structure includes an adhesive resin layer provided between a thermoplastic resin layer and a gas barrier resin layer, wherein the adhesive resin layer is formed from a resin composition containing a polyolefin resin (A) containing at least one of a carboxyl group and an acid anhydride group, and a fatty acid zinc salt (B), wherein the fatty acid zinc salt (B) is present in the resin composition in a proportion of 40 to 250 ppm on a metal basis based on the amount of the adhesive resin layer.