PTFE Composite Filter Material With Porous Adhesive Interface
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional polytetrafluoroethylene microporous membranes have low mechanical strength, poor adhesion with substrates, and compounding methods affect gas flux and filtration efficiency, leading to inadequate protection against airborne pathogens.
Innovation Solution
A polytetrafluoroethylene composite filter material is developed using a support layer and a polytetrafluoroethylene microporous membrane bonded with a two-component polyurethane adhesive containing a pore forming agent and inorganic filler, forming an irregular pore structure without obstructing micropores, maintaining air permeability and filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polytetrafluoroethylene microporous membrane is compounded with supporting materials to improve mechanical strength, then tensile strength is improved, but adhesion with substrate deteriorates due to low surface energy and poor wetting ability
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature (Tg) of the adhesive polymer between -50℃ and 50℃, and adjusting the weight ratio of adhesive to PTFE membrane (1:10 to 1:5). These parameter optimizations enable the adhesive to achieve adequate bonding strength with PTFE's low surface energy materials while maintaining flexibility and adhesion performance.
Solution Approach 2:
The patent uses composite materials by combining PTFE microporous membrane with a specially formulated adhesive polymer that has compatible surface energy characteristics. The adhesive layer acts as an intermediate composite material that bridges the PTFE membrane and the supporting substrate, resolving the adhesion problem caused by PTFE's inherently low surface energy.
2Strength
If hot melt bonding or coating sintering is used to compound PTFE microporous membrane, then mechanical strength is improved, but gas flux and filtration efficiency deteriorate due to dense interface layer formation
Solution Approach 1:
The patent employs porous materials by using a foam adhesive layer with controlled porosity instead of dense adhesive layers. The foam structure maintains open pores that allow gas permeation while providing adequate mechanical bonding, thus preserving gas flux and filtration efficiency while achieving composite strength.
Solution Approach 2:
The patent changes the physical state and density parameters of the adhesive by using foam adhesives with controlled cell structures. The adhesive layer maintains low density and high porosity (50-90%), preventing the formation of dense interface layers that would block gas flow, while still providing sufficient bonding strength through the foam structure's mechanical interlocking.
3Use of energy by moving object
If PTFE microporous membrane is fully heated before compounding to improve adhesion fastness, then adhesion is improved, but gas flux deteriorates due to dense layer formation at interface
Solution Approach 1:
The patent optimizes the heating temperature parameter within a specific range (50-150℃) that is sufficient to activate the adhesive's bonding properties without causing excessive melting or densification. This controlled thermal parameter change enables adequate adhesion fastness while preventing the formation of dense interface layers that would impede gas flux.
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 composite material achieves high peel strength, good filtration efficiency, and maintains air permeability while enhancing mechanical strength and filtration performance.
Implementation Method 1
adding a low-temperature pore forming agent and an inorganic filler, the pore forming agent forms an irregular pore channel structure at the bonding interface during curing
Implementation Method 2
The support layer and the polytetrafluoroethylene microporous membrane layer are compounded by an adhesive
Data Source
AI summary
A polytetrafluoroethylene composite filter material, and a preparation method and uses thereof, comprises a support layer and a polytetrafluoroethylene microporous membrane layer, and the support layer and the polytetrafluoroethylene microporous membrane layer are compounded by an adhesive, wherein the adhesive comprises a two-component polyurethane adhesive, a pore forming agent and an inorganic filler. By adding a two-component solvent-free polyurethane adhesive with a low-temperature pore forming agent and an inorganic filler, the pore forming agent forms an irregular pore channel structure at the bonding interface during curing, and the inorganic filler prevents the adhesive from entering the micropores of the polytetrafluoroethylene membrane, so that the air permeability and filtration efficiency of the polytetrafluoroethylene microporous membrane are not affected after compounding. The polytetrafluoroethylene composite filter material has good air permeability, high peel strength, good filtration efficiency and good barrier effect.