Epoxy Resin Curing Agent for High Gas-Barrier Adhesives
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Solution Overview
Problem
Current epoxy resin adhesives for packaging materials face challenges in achieving high gas-barrier properties and sufficient adhesiveness to polyester, often requiring additional gas-barrier layers which increase production costs and reduce workability, while also having slow curing rates and issues with unreacted isocyanate groups forming air bubbles.
Innovation Solution
A specific epoxy resin curing agent comprising a reaction product of m-xylylenediamine, a polyfunctional compound forming amide linkages, and aromatic dicarboxylic acid derivatives, which forms a cohesive amide linkage-based adhesive with high gas-barrier and adhesive properties, eliminating the need for separate gas-barrier layers and improving humidity resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional epoxy resin adhesives are used, then good adhesiveness and heat resistance are achieved, but gas-barrier properties are insufficient requiring additional layers
Solution Approach 1:
The invention changes the chemical composition parameters of the epoxy resin adhesive by incorporating specific amine curing agents (polyaminodiphenylmethane, diaminodiphenylsulfone, or their mixtures) to achieve superior gas-barrier properties without adding structural layers
Solution Approach 2:
The invention creates a composite adhesive system by combining epoxy resin with specific amine curing agents that possess both adhesive functionality and gas-barrier properties, achieving multi-functionality in a single material layer
2Reliability
If additional gas-barrier layers are added to improve gas-barrier properties, then gas-barrier performance increases, but production costs increase and workability decreases
Solution Approach 1:
The epoxy resin adhesive is designed to perform multiple functions simultaneously: providing adhesiveness, heat resistance, and high gas-barrier properties, eliminating the need for separate gas-barrier layers and simplifying the manufacturing process
3Strength
If two-part polyurethane adhesive is used, then high adhesiveness is achieved, but curing rate is slow requiring long-term aging
Solution Approach 1:
The invention changes the chemical composition by selecting specific amine curing agents with appropriate reactivity toward epoxy groups, achieving both high adhesiveness and accelerated curing rate without requiring long-term aging
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 solution provides laminate films with excellent gas-barrier, adhesive, and mechanical properties, enhancing the protection and preservation of packaged contents without additional gas-barrier layers, while maintaining stability under high humidity conditions.
Implementation Method 1
a curing agent comprising a reaction product of components (A), (B), and (C): (A) m-xylylenediamine or p-xylylenediamine; (B) a polyfunctional compound having one acyl group, which forms amide linkage by a reaction with polyamine
Implementation Method 2
a polyfunctional compound having one acyl group, which forms amide linkage by a reaction with polyamine and is capable of forming an oligomer
Data Source
AI summary
An epoxy resin curing agent which provides good adhesiveness to polyester in addition to excellent performance and high gas-barrier properties of epoxy resins, an epoxy resin composition containing the epoxy resin curing agent, an adhesive for laminating which mainly contains the composition, a laminate film obtained by using the adhesive, a multi-layer packaging material, and a packaging bag. The epoxy resin curing agent is a reaction product of (A) m-xylylenediamine or p-xylylenediamine, (B) a polyfunctional compound having one acyl group, which forms amide linkage by a reaction with polyamine and is capable of forming an oligomer; and (C) an aromatic dicarboxylic acid, an ester thereof, an amide thereof, an acid anhydride thereof, or an acid chloride thereof.