Heat-Curing Adhesive Sheet Epoxy Exudation Control
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Solution Overview
Problem
Conventional adhesive compositions for Flexible Printed Circuits (FPCs) face issues with unreacted epoxy resin exudation during hot-press forming, requiring additional UV irradiation steps and special storage conditions, which increase capital investment and complexity.
Innovation Solution
A heat-curing resin composition comprising an acrylic copolymer with epoxy group-containing (meth)acrylic ester monomers, an epoxy resin, and a curing agent, where part of the epoxy groups are cross-linked using liquid polyamine or polyamidoamine, eliminating the need for UV irradiation and improving exudation control during hot-press forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive composition containing a large amount of epoxy resin is used, then adhesive strength is improved, but unreacted epoxy resin exudes during hot-press forming causing drilled portions to be plugged
Solution Approach 1:
The invention performs preliminary cross-linking of part of the epoxy groups (5-50%) with liquid polyamine or liquid polyamidoamine before the hot-press forming process. This pre-cross-linking creates a partial network structure that prevents excessive exudation during subsequent heating, while leaving sufficient unreacted epoxy groups to ensure high adhesive strength after complete curing.
Solution Approach 2:
The invention changes the chemical state of a portion of the epoxy groups from unreacted to cross-linked by introducing liquid polyamine or liquid polyamidoamine. This parameter change (cross-linking degree) allows the material to have both high strength (from complete epoxy content) and reduced exudation (from pre-cross-linked portion) simultaneously.
2Object-generated harmful factors
If UV irradiation is used to prevent adhesive composition exudation, then exudation is controlled, but capital investment for UV equipment and special storage conditions are required
Solution Approach 1:
The invention replaces the UV irradiation system (optical/energy-based) with a chemical cross-linking system using liquid polyamine or liquid polyamidoamine. This substitution eliminates the need for UV equipment, special storage conditions, and complex irradiation processes, while achieving the same goal of controlling exudation through chemical pre-cross-linking.
Solution Approach 2:
The liquid polyamine or liquid polyamidoamine performs dual functions: it cross-links with epoxy groups to prevent exudation, and simultaneously serves as a curing agent that completes the curing process during hot-press forming. This self-service approach eliminates the need for separate UV irradiation equipment and special storage infrastructure.
3Object-generated harmful factors
If liquid polyamine or liquid polyamidoamine is used to cross-link epoxy groups, then exudation is reduced, but the curing process becomes more complex
Solution Approach 1:
The liquid polyamine or liquid polyamidoamine is designed to perform multiple functions: it cross-links with epoxy groups to prevent exudation, acts as a curing agent for complete curing during hot-press forming, and provides flexibility to the adhesive material. This multi-functionality simplifies the overall process by eliminating the need for separate UV irradiation step while achieving exudation control.
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 effectively reduces unreacted epoxy resin exudation, enhances normal-temperature storage performance, and maintains high adhesive strength and moisture-absorption solder heat-resistance, simplifying handling and storage without the need for specialized equipment.
Implementation Method 1
part of epoxy groups of the above-mentioned acrylic copolymer are cross-linked by liquid polyamine or liquid polyamidoamine, each having at least one of a primary amino group and a secondary amino group
Implementation Method 2
an epoxy resin; and a curing agent for the epoxy resin
Data Source
AI summary
The present invention provides a heat-curing resin composition which is curable without UV irradiation or the like and in which exudation of unreacted epoxy resin and the like at the time of pressure thermoforming is satisfactory. The heat-curing resin composition comprises: an acrylic copolymer containing an epoxy group-containing (meth)acrylic ester monomer; an epoxy resin; and a curing agent for the epoxy resin, wherein the curing agent contains organic acid dihydrazide, and part of epoxy groups of the acrylic copolymer are cross-linked by liquid polyamine or liquid polyamidoamine, each having at least one of a primary amino group and a secondary amino group.