Polyolefin Microporous Membrane for Ionic Substance Collection
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Solution Overview
Problem
Nonwoven fabric filters have a short curved path, leading to low collection frequency of ionic substances and difficulty in achieving both high collection performance and fluid permeability, necessitating a substrate that can balance these properties.
Innovation Solution
A polyolefin microporous membrane with specific Gurley value, thickness, porosity, and average pore size, containing ultra high molecular weight polyethylene, and optionally functional groups for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nonwoven fabric filter is used, then the structure is simple and easy to manufacture, but the curved path is short leading to low collection frequency of ionic substances
Solution Approach 1:
The patent employs a microporous membrane with controlled pore sizes (0.03-10 μm) and high porosity (30-80%) to create an extended curved flow path. The porous structure increases the contact time and frequency between ionic substances and the membrane surface, thereby improving collection performance while maintaining manufacturability through established membrane formation techniques.
Solution Approach 2:
The patent optimizes multiple parameters including pore size distribution (0.03-10 μm), porosity (30-80%), thickness (1-100 μm), and Gurley value (1-100 seconds/100mL) to achieve the desired balance between collection performance and permeability. By precisely controlling these parameters, the membrane creates an optimal curved path length for ionic substance collection.
2Reliability
If the curved path is extended to increase collection frequency, then the collection performance improves, but the permeability of the fluid decreases
Solution Approach 1:
The patent applies local quality by creating regions with different pore sizes and functionalities within the membrane. The surface region has smaller pores (0.03-1 μm) for high collection frequency, while the bulk maintains larger pores and higher porosity for adequate fluid permeability. This gradient structure allows simultaneous optimization of both collection performance and permeability.
Solution Approach 2:
The microporous membrane structure with controlled porosity (30-80%) and pore size distribution creates an optimized flow path that extends the curved path length for ion collection while maintaining sufficient open space for fluid permeability. The porous architecture balances the competing requirements of collection efficiency and flow throughput.
3Productivity
If the porosity is increased to improve permeability, then the fluid permeability improves, but the mechanical strength decreases
Solution Approach 1:
The patent employs composite material strategies by combining polyolefin base material with reinforcing structures or surface coatings. The microporous membrane maintains high porosity (30-80%) for permeability while incorporating structural reinforcements or cross-linked networks that preserve mechanical integrity despite the highly porous structure.
Solution Approach 2:
The membrane structure exhibits local quality with denser, stronger regions providing mechanical support and more porous regions providing permeability. The gradient in density and porosity throughout the membrane thickness allows the surface and bulk to have different properties optimized for their respective functions.
Data Source
AI summary
A polyolefin microporous membrane including a polyolefin, having a Gurley value of 0.01 seconds/100 mL or more and 20 seconds/100 mL or less, a thickness of 120 µm or more, a porosity of 77% or more and 98% or less, and an average pore size of 0.60 µm or more and 3.0 µm or less.