Chain Extended Epoxy Adhesion High Silver Loading
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Solution Overview
Problem
Conductive adhesive films with high silver or silver-plated copper loadings face a decline in adhesion, compromising thermal and electrical conductivity while maintaining sufficient adhesive properties.
Innovation Solution
A conductive adhesive film composition incorporating a thermosetting resin, a film-forming resin, and a chain extended epoxy resin, prepared from the reaction of a poly-functional phenol with a combination of poly-functional aromatic and aliphatic epoxies, which preserves adhesiveness at silver loadings of 80 wt% or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver or silver-plated copper loading is increased to improve thermal and electrical conductivity, then conductivity is improved, but adhesion of the conductive adhesive film declines
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive matrix by incorporating chain extended epoxy resin with specific molecular weight and functionality. This changes the adhesive properties of the matrix to compensate for the reduced adhesion caused by high silver loading, thereby maintaining both conductivity and adhesion simultaneously
Solution Approach 2:
The patent creates a composite adhesive system combining multiple resin components (epoxy, phenolic, polyamide) with high silver filler content. The composite matrix structure provides both the necessary adhesion and the conductive pathway support, resolving the contradiction between high filler loading and adequate adhesion
2Reliability
If silver loading is increased to achieve required conductivity properties, then conductivity is improved, but adhesive shear strength is reduced
Solution Approach 1:
The patent adjusts the molecular weight and functionality parameters of the epoxy resin to optimize the adhesive matrix. By selecting epoxy resin with specific characteristics and combining it with other resins, the adhesive shear strength is enhanced to match the mechanical properties of high silver loading formulations
3Reliability
If conventional conductive filler loading exceeds 80 weight percent to obtain conductivity properties, then conductivity is improved, but adhesion of the film declines
Solution Approach 1:
The patent changes the chemical and physical parameters of the adhesive matrix by using chain extended epoxy resin with controlled molecular weight (500-5000) and specific functionality. This parameter optimization allows the matrix to maintain adequate adhesion even when silver filler constitutes 80 wt% or more of the formulation
Solution Approach 2:
The epoxy-phenolic-polyamide resin matrix acts as an intermediary between the high silver filler loading and the substrate. This intermediate matrix material provides the bonding interface that compensates for the poor adhesion inherent in high filler loadings, enabling both high conductivity and adequate adhesion
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 addition of chain extended epoxy resin enhances the adhesive shear strength of conductive adhesive films, maintaining adhesiveness and conductivity even at high silver filler concentrations.
Implementation Method 1
a chain extended epoxy resin prepared from the reaction of a poly-functional phenol with a combination of a poly-functional aromatic epoxy and a poly-functional aliphatic epoxy
Data Source
AI summary
A conductive adhesive film is prepared from components comprising a thermosetting resin, a film-forming resin, a conductive filler, and further comprising a chain extended epoxy resin prepared from the reaction of a poly-functional phenol with a combination of a poly-functional aromatic epoxy and a poly-functional aliphatic epoxy (poly-functional includes di-functional). The addition of the chain extended epoxy preserves the adhesiveness of the conductive adhesive film at silver loadings of 80 weight percent or greater.