Anisotropic Conductive Adhesive Composition for Low-Heat Printed Electronics
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Solution Overview
Problem
Existing methods for connecting printed electronics to cables, PCBs, or FCBs face challenges such as high temperature requirements, mechanical instability, high material costs, and inadequate adhesion, making them unsuitable for flexible and cost-effective assembly.
Innovation Solution
An anisotropically conductive heat activated adhesive composition comprising thermoplastic resin, metal-coated particles, and specific solvents, which can be printed and dried at moderate temperatures, providing a thin, conductive connection only in one direction without a tacky surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soldering is used to connect printed electronics, then strong and durable joint is achieved, but high temperature is required which is detrimental to printed electronics and substrate
Solution Approach 1:
The invention changes the temperature parameter from high (soldering) to moderate (adhesive curing), enabling connection of heat-sensitive substrates like TPU while maintaining joint strength through chemical adhesion rather than thermal bonding
Solution Approach 2:
The invention replaces the thermal-mechanical soldering process with a chemical adhesive bonding process, where the adhesive composition forms chemical bonds with both the printed electronics and substrate, eliminating the need for high temperature melting and solidification
2Reliability
If electrically conductive adhesive (ECA) is used to form connection, then electrical conductivity is achieved, but high material costs are incurred due to high silver concentration
Solution Approach 1:
The invention uses a composite adhesive composition containing conductive filler particles (metal, carbon, or graphite) dispersed in a thermoplastic resin matrix, providing electrical conductivity through the filler network while the resin provides mechanical strength and adhesion, reducing dependence on high silver concentration
Solution Approach 2:
The invention employs cost-effective conductive fillers such as carbon black, graphite, or base metal particles coated with conductive material, replacing expensive pure silver fillers while achieving sufficient conductivity for the application
3Reliability
If anisotropically conductive adhesive tapes are used, then connection is formed, but the connection layer is thick and has a tacky surface with only moderate adhesion properties
Solution Approach 1:
The invention changes the adhesive layer thickness parameter to be thin by using a printable paste composition that cures to a thin solid layer, eliminating the tacky surface issue and providing excellent adhesion through chemical bonding and mechanical interlocking
Solution Approach 2:
The invention replaces the tape-based mechanical adhesion system with a printable paste that undergoes thermal curing to form a chemically bonded adhesive layer, transitioning from physical tack to chemical adhesion for superior bonding strength
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
Enables reliable, durable, and cost-effective connections without thermal or mechanical impairment, allowing reprocessing and adhesion after thermal lamination, with improved peel strength and conductivity.
Implementation Method 1
wherein the one or more thermoplastic resin is dissolved into the solvent
Implementation Method 2
which can be printed and dried at moderate temperatures, providing a thin, conductive connection
Implementation Method 3
providing a thin, conductive connection only in one direction
Implementation Method 4
Enables reliable, durable, and cost-effective connections without thermal or mechanical impairment, allowing reprocessing and adhesion after thermal lamination
Data Source
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Figure 2b
AI summary
The present invention relates to an anisotropically conductive heat activated adhesive composition, comprising a) one or more thermoplastic resin; b) metal coated particles; and c) a solvent selected from the group consisting of 1-methoxy-2-propanylacetate, 2-butoxyethyl acetate, 2-(2-butoxyethoxy)ethanol, [2-(2-butoxyethoxy)-ethyl]acetate, 2-butoxyethanol, isophorone, 3,3,5-trimethyl-2-cyclohexene-1-one, dimethyl succinate, dimethyl glutarate, dimethyl adipate, acetic acid, 1-methoxypropan-2-ol, 1-methoxy-2-propylacetat, dipropylene glycol (mono)methyl ether, toluene, ethanol, isopropyl alcohol, n-propanol, ethoxy propanol, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, methyl ethyl ketone, methyl isobutyl ketone, glycol ethers and mixtures thereof, wherein the one or more thermoplastic resin is dissolved into the solvent. The composition can be used in electronic devices.