Expanded Fluoropolymer Membrane with Fused Thermoplastic Network
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Solution Overview
Problem
Existing porous composites face challenges in achieving a balance between breathability and structural integrity, often compromising on one aspect to achieve the other, and require expensive, hard-to-attach fluoropolymer support materials, especially in high-temperature or chemically aggressive environments.
Innovation Solution
The development of porous articles featuring an expanded fluoropolymer layer with a coherent irregular network of thermoplastic particles, which provides both dimensional stability and high permeability without significantly reducing breathability, by attaching the network to the fluoropolymer in a way that maintains its porous structure and enhances mechanical reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fluoropolymer support materials are used to provide dimensional stability and mechanical reinforcement, then structural integrity is improved, but cost increases and attachment difficulty increases
Solution Approach 1:
The patent changes the physical state of the fluoropolymer from pre-formed support materials to a melt-processable state. By heating the fluoropolymer coating to its melting point, it transitions from a solid powder to a molten state that can flow and bond to the expanded fluoropolymer, then solidifies upon cooling to form a strong attachment. This parameter change (temperature) enables easy attachment while maintaining structural integrity.
Solution Approach 2:
The invention utilizes the phase transition of the fluoropolymer coating material from solid to liquid and back to solid. The coating is applied as solid particles, heated to melt and bond to the expanded fluoropolymer substrate, then cooled to solidify and form a durable attachment. This phase transition mechanism simplifies the attachment process while ensuring strong mechanical reinforcement.
2Strength
If durable materials are used to achieve structural integrity, then strength is improved, but breathability is compromised
Solution Approach 1:
The patent applies the fluoropolymer coating only in specific locations on the expanded fluoropolymer substrate - primarily at the seams and high-stress areas where mechanical reinforcement is needed. The rest of the fabric maintains its original porous structure and breathability. This localized application of durable material provides structural integrity where needed without compromising overall breathability.
Solution Approach 2:
The invention creates a composite structure combining expanded fluoropolymer fabric with a fluoropolymer coating layer. The expanded fluoropolymer provides breathability through its porous structure, while the coating layer provides durability and structural integrity. The two materials work together in a composite system that achieves both breathability and strength simultaneously.
3Quantity of substance
If expanded fluoropolymer is used to maintain breathability, then permeability is improved, but dimensional stability deteriorates
Solution Approach 1:
The fluoropolymer coating is applied to the expanded fluoropolymer fabric before final product assembly. This preliminary coating creates a stable base layer that will prevent dimensional changes during subsequent processing and use. The coating adheres to the fabric structure, locking it in place and preventing shrinkage or deformation under heat or mechanical stress.
Solution Approach 2:
The composite structure of expanded fluoropolymer fabric with fluoropolymer coating provides both breathability and dimensional stability. The expanded fluoropolymer maintains its porous structure for breathability, while the coating layer acts as a stabilizing shell that prevents dimensional changes. Together they form a composite material that exhibits both properties simultaneously.
4Strength
If fluoropolymer coating is applied and heated to fuse particles, then attachment strength is improved, but energy consumption increases
Solution Approach 1:
The fluoropolymer coating material serves a dual function: it is both the attachment medium and the energy source for its own bonding process. When heated, the fluoropolymer melts and bonds to the expanded fluoropolymer substrate, and the same thermal energy facilitates the fusion of coating particles to each other. The material itself enables the bonding process without requiring separate adhesives or complex bonding mechanisms.
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 solution achieves a balance between breathability and structural integrity, maintaining high permeability and increasing the strength and abrasion resistance of the expanded fluoropolymers while being dimensionally stable at high temperatures, and easy to attach, using a cost-effective and widely available material configuration.
Implementation Method 1
heating to a temperature sufficient to melt the thermoplastic fluoropolymer particles and fuse them together
Implementation Method 2
fuse them together to form a coherent irregular network
Implementation Method 3
Expanded PTFE is porous; allowing fluid to pass there through
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
Porous articles having an expanded fluoropolymer and a coherent irregular network are described. In one embodiment, the coherent irregular network is attached to the expanded fluoropolymer at only a portion of the adjacent region. In another aspect of the invention the coherent irregular network is a free standing film. The coherent irregular network in one embodiment has a surface roughness defined by an Sp value of greater than 35um.