PTFE Nanofiber Substrate with Conductive Layer for Wearable Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flexible printed circuit boards for wearable devices require higher flexibility, air permeability, and heat resistance, as existing boards suffer from insufficient heat resistance and thermal contraction issues.
Innovation Solution
A substrate with a conductive layer formed from a woven or nonwoven fabric of polytetrafluoroethylene (PTFE) nanofibers, using a conductive composition with a viscosity of 1 to 500 Pa·s, which provides high air permeability and heat resistance, and is bonded with a thermosetting resin to prevent separation and wire breakage during bending and thermal exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermosetting conductive composition is used to form a conductive layer, then heat resistance is improved, but thermal contraction occurs and flexibility deteriorates
Solution Approach 1:
The patent changes the viscosity parameter of the conductive composition to a specific range (10 to 100 Pa·s) to achieve optimal balance between heat resistance and flexibility. This parameter optimization allows the composition to maintain structural integrity at high temperatures while remaining flexible enough for wearable applications.
Solution Approach 2:
The patent uses a composite conductive composition containing conductive filler particles dispersed in a thermosetting resin matrix. This composite structure provides both the heat resistance from the thermosetting resin and the flexibility needed for wearable devices, resolving the contradiction between these two properties.
2Ease of operation
If a known flexible printed circuit board is used, then flexibility is improved, but air permeability is insufficient
Solution Approach 1:
The patent employs a porous substrate made of expanded polytetrafluoroethylene (e-PTFE) with controlled pore structure. This porous material provides both the flexibility required for wearable devices and sufficient air permeability for breathability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent adopts the e-PTFE substrate structure from existing flexible circuit board designs but optimizes its pore size and distribution to enhance air permeability while maintaining flexibility, effectively copying and improving upon the proven flexible substrate concept.
3Ease of operation
If a conductive layer is formed on a PTFE substrate, then flexibility is maintained, but adhesion is insufficient causing separation and wire breakage
Solution Approach 1:
The patent optimizes the viscosity parameter of the conductive composition (10 to 100 Pa·s) to achieve optimal adhesion to the PTFE substrate. This viscosity control ensures the composition flows adequately to wet the substrate surface and forms strong bonds, preventing separation and wire breakage while maintaining flexibility.
Solution Approach 2:
The thermosetting resin in the conductive composition acts as an intermediary bonding agent between the conductive filler and the PTFE substrate. This resin matrix provides adhesion promotion, ensuring strong bonding while allowing the overall structure to remain flexible.
4Ease of operation
If existing flexible printed circuit boards are used, then flexibility is improved, but heat resistance is insufficient for sterilization
Solution Approach 1:
The patent uses a composite conductive composition with thermosetting resin that provides high heat resistance capable of withstanding autoclave sterilization temperatures. The e-PTFE substrate combined with this heat-resistant composition maintains flexibility while achieving the required sterilization resistance.
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 substrate achieves high flexibility, air permeability, and heat resistance, allowing it to withstand sterilization and maintain conductivity without shape change or separation, making it suitable for wearable devices and healthcare applications.
Implementation Method 1
a conductive layer formed on the substrate, the conductive layer being formed from a conductive composition with a viscosity in a range of 1 to 500 Pa·s measured at 25° C. with a rotational viscometer at a rotational speed of 50 rpm
Implementation Method 2
a conductive layer formed on the substrate, the conductive layer being formed from a conductive composition with a viscosity in a range of 1 to 500 Pa·s measured at 25° C. with a rotational viscometer at a rotational speed of 50 rpm, wherein the following requirement (1) is satisfied: requirement (1): the substrate with a conductive layer has a Gurley permeability of 10 s/100 ml or less
Implementation Method 3
a substrate with a conductive layer including: a substrate, which is a woven or nonwoven fabric containing polytetrafluoroethylene (PTFE) nanofibers
Implementation Method 4
the substrate with a conductive layer has high heat resistance, and therefore can be subjected to sterilization, such as autoclave sterilization, when used in healthcare applications
Data Source
AI summary
A substrate with a conductive layer including a substrate, which is a woven or nonwoven fabric containing polytetrafluoroethylene (PTFE) nanofibers; and a conductive layer formed on the substrate, the conductive layer being formed from a conductive composition with a viscosity in a range of 1 to 500 Pa·s measured at 25° C. with a rotational viscometer at a rotational speed of 50 rpm, wherein the following requirement (1) is satisfied: requirement (1); the substrate with a conductive layer has a Gurley permeability of 10 s/100 ml or less.