Polyolefin Membrane for Liquid Filter Pore Blockage
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Solution Overview
Problem
Current liquid filters face a trade-off between collection efficiency for particles of 10 to 50 nm and liquid permeability, with long-term use often resulting in decreased permeability and potential pore blockage due to the fragile nature of polyolefin microporous membranes.
Innovation Solution
A polyolefin microporous membrane with specific properties, including a water permeation efficiency of 0.51 to 1.20 ml/min·cm2, a bubble point of 0.45 to 0.70 MPa, compressibility less than 15%, heat shrinkage of 15% or more, thickness of 7 to 16 μm, pore-blocking temperature above 140°C, and porosity of 50 to 58%, is developed to maintain excellent collection efficiency and stable liquid permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyolefin microporous membrane is used as a substrate for liquid filter, then the liquid filter can remove particles of 10 to 50 nm, but the liquid permeability decreases and the porous structure changes due to repeated pressure application
Solution Approach 1:
The patent applies parameter changes by precisely controlling the water permeation efficiency (0.51 to 1.20 ml/min·cm2), bubble point (0.45 to 0.70 MPa), compressibility (less than 15%), heat shrinkage (15% or more), thickness (7 to 16 μm), pore-blocking temperature (above 140°C), and porosity (50 to 58%). By optimizing these parameters within specific ranges, the membrane achieves both high collection efficiency for particles of 10 to 50 nm and stable liquid permeability, resolving the contradiction between filtration performance and productivity
Solution Approach 2:
The patent employs composite material principles by creating a polyolefin microporous membrane with a specific composite structure that combines high porosity (50 to 58%) with controlled compressibility (less than 15%). This composite structure allows the membrane to maintain its porous architecture under pressure while achieving effective particle collection, thus simultaneously improving both collection efficiency and liquid permeability
2Stability of the object's composition
If the polyolefin microporous membrane is made more rigid to maintain porous structure, then long-term stability improves, but collection efficiency and liquid permeability are affected
Solution Approach 1:
The patent resolves this contradiction by changing the physical parameters of the membrane, specifically setting compressibility to less than 15% and heat shrinkage to 15% or more. These parameter adjustments allow the membrane to have sufficient rigidity to maintain its porous structure under repeated pressure application, while still achieving excellent collection efficiency for particles of 10 to 50 nm through controlled porosity (50 to 58%) and optimized pore distribution
3Productivity
If the polyolefin microporous membrane is used for long term, then filtration capacity increases, but pore blockage occurs and original porous structure cannot be maintained
Solution Approach 1:
The patent applies beforehand cushioning by pre-optimizing the membrane's compressibility (less than 15%) and pore-blocking temperature (above 140°C) to prevent pore blockage before it occurs during long-term use. The membrane's structure is designed to resist compression and maintain its porous architecture, thereby preventing pore blockage and preserving filtration capacity over extended periods
Solution Approach 2:
The patent uses parameter changes by establishing specific ranges for water permeation efficiency (0.51 to 1.20 ml/min·cm2), porosity (50 to 58%), and compressibility (less than 15%) that enable the membrane to maintain its porous structure during long-term filtration operations, preventing pore blockage while sustaining high filtration capacity
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 enables a substrate for liquid filters with enhanced collection efficiency and stable liquid permeability for long-term use, preventing pore blockage and maintaining high filtration performance.
Implementation Method 1
A liquid chemical prepared at high level is filtered through a dense filter immediately before application onto a wafer to remove particles that would greatly affect the pattern formation or yield.
Implementation Method 2
a porous membrane made of a resin such as polyethylene, polytetrafluoroethylene, nylon, or polypropylene
Data Source
AI summary
A substrate for a liquid filter, which includes a polyolefin microporous membrane, the polyolefin microporous membrane having a water permeation efficiency of 0.51 to 1.20 ml/min·cm2, the polyolefin microporous membrane having a bubble point of 0.45 MPa or more and 0.70 MPa or less, the polyolefin microporous membrane having a compressibility of less than 15%.