Conductive Polymer Adhesive With Flexible Filler Interface
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Solution Overview
Problem
Existing conductive adhesives for flexible electronic devices face challenges in maintaining adhesive strength and electrical conductivity under external stress, leading to reliability issues due to high rigidity and shrinkage phenomena, particularly in epoxy-based materials.
Innovation Solution
A conductive polymer composite comprising a curable polymer, a curing agent, and a conductive filler with a substituting agent to remove or substitute a lubricant layer, ensuring flexibility and stretchability while maintaining electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy-based conductive adhesive is used, then strong adhesive strength is achieved, but high rigidity and shrinkage phenomenon occur leading to poor flexibility
Solution Approach 1:
The patent changes the polymer material parameters from epoxy-based to silicone-based resin, fundamentally altering the material's mechanical properties. This parameter change enables the adhesive to achieve both strong bonding strength and high flexibility, resolving the contradiction between adhesive strength and flexibility by selecting a different polymer base material with inherently superior elastomeric properties
Solution Approach 2:
The patent creates a composite conductive adhesive system by combining silicone-based resin with conductive fillers (silver particles, aluminum powder, or carbon black) and specific modifiers. This composite approach allows the adhesive to simultaneously exhibit flexibility from the silicone matrix, conductivity from the fillers, and controlled rheology from the modifiers, resolving the contradiction between strength and flexibility
2Adaptability or versatility
If substrate is stretched or contracted by external stress, then flexibility is achieved, but adhesive properties and conductivity cannot be continuously maintained
Solution Approach 1:
The patent introduces dynamic capabilities to the adhesive system by incorporating plasticizers and viscosity modifiers that allow the silicone-based adhesive to dynamically adjust its mechanical properties in response to external stress. The adhesive can soften and extend under tension, then recover its original properties when stress is removed, maintaining both stretchability and reliable adhesive/conductive properties throughout the deformation cycle
Solution Approach 2:
The patent uses specific silicone-based resin formulations with controlled molecular weight and crosslinking density, combined with plasticizers, to create an adhesive whose physical parameters (viscosity, modulus, elongation) can dynamically change in response to external stress while maintaining stable adhesive and conductive properties through the curing process
3Stability of the object's composition
If lubricant layer is present on conductive filler, then dispersion is improved, but electrical conductivity decreases
Solution Approach 1:
The patent introduces silane coupling agents as intermediary substances that chemically bridge the conductive filler particles and the silicone-based resin matrix. These coupling agents replace or modify the traditional lubricant layer, providing both adequate dispersion stability through surface modification and maintained electrical conductivity by creating conductive pathways at the filler-matrix interface
Solution Approach 2:
The patent changes the surface chemistry parameters of the conductive fillers by treating them with silane coupling agents, transforming the surface from lubricant-coated to silane-modified. This parameter change in surface chemistry enables the fillers to maintain both good dispersion in the silicone matrix and high electrical conductivity, eliminating the need for lubricant layers
Data Source
AI summary
Disclosed is a conductive polymer composite according to various embodiments of the present invention in order to implement the above-described object. The conductive polymer composite may include a polymer adhesive which includes a curable polymer and a curing agent, a conductive filler made of a metal having electrical properties, and a substituting agent configured to substitute for or remove a lubricant layer applied on the conductive filler.