Composite Membrane Lamination Without Adhesive
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Solution Overview
Problem
The production of composite ePTFE membranes often results in reduced porosity due to the presence of a bonding agent between laminated layers, which is undesirable for applications requiring controlled porosity and chemical resistance.
Innovation Solution
A process involving the lamination of three porous membranes of the same polymeric material, where the middle membrane has larger pores than the outer membranes, allowing bonding without a separate adhesive material, thereby maintaining porosity and using heat and pressure to bond the membranes through resolidified portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bonding agent is used to laminate PTFE membranes together, then the membranes can be bonded effectively, but the porosity of the composite membrane is reduced
Solution Approach 1:
The patent removes the bonding agent from the lamination process entirely. Instead of using an external adhesive material, the PTFE membranes are bonded directly to each other through heat and pressure, allowing the membranes to fuse without any intermediate substance that would block pores and reduce porosity.
Solution Approach 2:
The PTFE membranes bond to each other using their own material properties. The membranes serve as both the structure to be bonded and the bonding medium, eliminating the need for separate adhesive materials. This self-bonding approach maintains porosity while achieving effective lamination.
2Strength
If multiple porous membranes are laminated together with a bonding agent, then composite membrane strength is improved, but the chemical resistance and porosity are compromised
Solution Approach 1:
The patent uses identical PTFE membranes for all layers being laminated. This homogeneity ensures that the entire composite membrane maintains uniform chemical resistance properties throughout, as no foreign bonding agents with different chemical properties are introduced into the structure.
3Ease of manufacture
If bonding agents are applied between membrane layers, then lamination is achieved, but pore blockage increases and filtration efficiency decreases
Solution Approach 1:
The bonding agent is completely removed from the lamination process. The membranes are bonded through direct contact and fusion under heat and pressure, eliminating any substance that could block pores and maintain precise control over pore size and filtration characteristics.
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
This method enables the creation of composite membranes with enhanced porosity and chemical resistance, suitable for various applications, including microventing and liquid filtration, by eliminating the need for extraneous bonding agents and minimizing pore blockage.
Implementation Method 1
applying heat and pressure to the first, second and third porous membranes to laminate the porous membranes together
Implementation Method 2
applying heat and pressure to the first, second and third porous membranes to laminate the porous membranes together
Data Source
AI summary
Composite membrane materials and process for their production. The process entails the use of at least first and second porous membranes formed of a polymeric material and at least a third porous membrane formed of the same polymeric material, but having larger pores than the first and second porous membranes. The first, second and third porous membranes are laminated together by applying heat and pressure to the first, second and third porous membranes without applying a separate adhesive material therebetween. The laminated first, second and third porous membranes form a composite membrane in which the third porous membrane is between the first and second porous membranes.