Conductive Adhesive Composition for Flexible Electronics
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Solution Overview
Problem
Current conductive adhesive compositions, particularly those using silver nanoparticles, face challenges with adhesion to electronic components, jettability issues in printing technologies, and high viscosity, making them unsuitable for digital printing on flexible plastic substrates, which limits their application in printed electronics.
Innovation Solution
A conductive adhesive composition comprising epoxy resin, polyvinyl phenols or polyvinyl butyrals, melamine resin, and metal nanoparticles with an average size of 0.5 to 100 nanometers, which can be jetted and cured at low temperatures, providing high conductivity and adhesion while being suitable for digital printing on various substrates, including flexible plastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silver nanoparticle inks are used for low temperature processing, then they can be used on flexible plastic substrates, but they do not adhere well to electronic components
Solution Approach 1:
The patent combines silver nanoparticles with adhesive polymers (polyvinyl phenol, polyvinyl butyral) and crosslinking agents (melamine resin, epoxy resin) to create a composite material that simultaneously provides conductivity, adhesion, and low-temperature processing capability. The adhesive matrix binds the metal particles to the substrate while the crosslinking agents enhance bonding strength through chemical reactions at low temperatures.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the adhesive composition by incorporating specific polymers and crosslinking agents that enable low-temperature curing. The gel fraction and crosslinking density are controlled to achieve optimal adhesion at temperatures below 150°C, transforming the material properties to suit flexible substrate requirements.
2Strength
If traditional conductive adhesive pastes are used to ensure good adhesion, then they provide strong bonding, but they have high viscosity and are unsuitable for inkjet printing
Solution Approach 1:
The patent adjusts the viscosity and rheological parameters of the conductive adhesive by selecting appropriate polymer molecular weights, concentrations, and solvent types. The composition is formulated to have low enough viscosity for inkjet printing while maintaining sufficient adhesion strength through the chemical crosslinking mechanism that occurs after deposition.
Solution Approach 2:
The patent incorporates crosslinking agents and adhesive polymers in the liquid formulation before printing, so that the adhesion-promoting chemistry is already prepared in the ink. After inkjet deposition, the crosslinking reaction proceeds to create strong bonds, eliminating the need for separate adhesion treatment steps.
3Reliability
If anisotropic conductive adhesive is used to provide conductivity only in perpendicular direction, then it avoids interfering with substrate traces, but it is typically a paste with high viscosity greater than 2500 cps
Solution Approach 1:
The patent reduces the viscosity of anisotropic conductive adhesives by modifying the polymer matrix composition and crosslinking density. The formulation enables the adhesive to flow adequately for printing while maintaining the anisotropic conductive properties through controlled particle orientation and low-temperature curing that preserves the directional conductivity structure.
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 composition exhibits excellent adhesion, conductivity, and stability, enabling the formation of reliable conductive features on flexible substrates with improved dispersion and insulative properties, suitable for electronic devices requiring low curing temperatures and rapid curing times.
Implementation Method 1
conductive adhesive composition comprising at least one epoxy resin, at least one polymer chosen from polyvinyl phenols and polyvinyl butyrals, at least one melamine resin, a plurality of metal nanoparticles... demonstrate excellent adhesion strength, stability, and conductivity
Implementation Method 2
at least one epoxy resin, at least one melamine resin... demonstrate excellent adhesion strength
Implementation Method 3
conductive adhesive composition... demonstrate excellent adhesion strength
Data Source
AI summary
Provided herein is conductive adhesive composition comprising at least one epoxy resin, at least one polymer chosen from polyvinyl phenols and polyvinyl butyrals, at least one melamine resin, a plurality of metal nanoparticle shaving an average particle size ranging from about 0.5 nanometers to about 100 nanometers, and at least one solvent. Also provided herein is an electronic device comprising a substrate, conductive features disposed on the substrate, a conductive electrical component disposed over the conductive features, and a conductive adhesive composition disposed between the conductive features and the conductive electrical component. Further disclosed herein are methods of making a conductive adhesive composition.