Stretchable Conductive Fluoroelastomer Paste for Wearable Circuits
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Solution Overview
Problem
Existing technologies fail to provide electrical circuits in wearable garments that maintain conductivity during stretching and multiple wash and dry cycles, and also do not adequately address the deformation challenges in thermoforming and injection molding processes for In Mold Electronics.
Innovation Solution
A stretchable polymer thick film conductive paste composition comprising 45-65 wt % conductive powder, 10-20 wt % fluoroelastomer, 0.1-3 wt % silane coupling agent, and 0-35 wt % solvents, which forms a printed conductor that maintains electrical conductivity and durability during stretching and deformation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional conductive adhesives or soldering are used in wearable garments, then electrical circuits can be formed, but the circuits fail to maintain conductivity during stretching and wash/dry cycles
Solution Approach 1:
The patent changes the material parameters by using fluoroelastomer as the polymer matrix instead of traditional adhesives, and by optimizing the conductive powder content (45-65 wt%) and particle size distribution. This creates a paste composition that maintains conductivity (change in resistance less than 10%) during stretching and wash/dry cycles while providing the necessary adaptability to wearable garments
Solution Approach 2:
The patent creates a composite material system combining conductive powder (silver, copper, or aluminum), fluoroelastomer polymer matrix, and specific solvents (2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol monobutyl ether acetate, ethylene glycol diacetate, dibasic esters, and C11 ketones). This composite structure provides both the electrical conductivity needed for circuits and the elastic properties required for stretchability and durability during washing
2Reliability
If conventional conductive adhesives are used for In Mold Electronics, then electrical connections can be made, but the adhesives cannot tolerate stretching and deformation during thermoforming and injection molding
Solution Approach 1:
The patent modifies the adhesive parameters by formulating a paste composition with specific solvent ratios (0-35 wt% of first solvent group, 1-35 wt% of second solvent group), conductive powder content (45-65 wt%), and fluoroelastomer content (10-20 wt%). These parameter changes enable the adhesive to tolerate the high temperatures and mechanical deformation of thermoforming and injection molding while maintaining electrical connection stability
Solution Approach 2:
The fluoroelastomer-based paste forms a flexible, elastic film that can accommodate the stretching and deformation occurring during thermoforming and injection molding processes. This flexible film structure allows the electrical connections to remain stable even when subjected to the mechanical stresses of manufacturing processes
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 effectively forms a stretchable conductive polymer thick film that maintains electrical conductivity and durability during stretching and deformation, providing a reliable alternative to traditional soldering for wearable garments and In Mold Electronics.
Implementation Method 1
0.1-3 wt % silane coupling agent
Implementation Method 2
10-20 wt % fluoroelastomer; forms a stretchable conductive polymer thick film
Implementation Method 3
45-65 wt % conductive powder; forms a stretchable conductive polymer thick film
Data Source
AI summary
The invention relates to a polymer thick film (PTF) conductive paste composition comprising a conductive powder, a fluoroelastomer, a silane coupling agent, and one or solvents. The PTF conductive paste composition can be used to form a printed conductor and to form an electrically conductive adhesive on various articles. The PTF conductive paste composition is provides a stretchable electrical conductor for wearables.