Crystalline Polymer Microporous Membrane with Segmented Pore Structure
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Solution Overview
Problem
Current crystalline polymer microporous membranes struggle to efficiently capture fine particles, maintain high filtration rates, prevent clogging, and ensure long service life while maintaining durability due to limitations in pore structure and layer thickness.
Innovation Solution
A crystalline polymer microporous membrane is designed with a laminate structure comprising layers of high and low crystallinity polymers, where the high crystallinity layer has a thicker thickness and the low crystallinity layer is strategically positioned between the high crystallinity layers, with pores of varying diameters along the thickness direction to enhance filtration efficiency and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a multi-layer paste with different fusion thermal peaks is used to form pores, then the membrane structure is simplified, but fine particle capture efficiency deteriorates because pores with continuously changing diameters are not formed
Solution Approach 1:
The membrane is divided into multiple layers (first layer, second layer, third layer) with different pore diameter characteristics. The first and third layers have smaller pore diameters for fine particle capture, while the second layer has larger pore diameters for maintaining flow rate, creating a segmented filtration system that addresses both efficiency and productivity requirements
Solution Approach 2:
Different regions of the membrane are assigned different pore diameter characteristics tailored to their specific functions. The first layer near the feed side has smaller pores for initial fine particle capture, the second layer has larger pores for high flow rate, and the third layer has smaller pores again for final filtration, optimizing local filtration quality at each position
2Strength
If the thickness of the dense layer formed of low molecular weight crystalline polymer is increased to improve strength, then durability is improved, but filtration rate decreases and clogging occurs more easily
Solution Approach 1:
The membrane thickness is segmented into multiple layers with different functions. The first layer (5-20 μm) provides strength and fine particle capture, the second layer (20-50 μm) provides high flow rate with larger pores, and the third layer (5-20 μm) provides final filtration. This segmentation allows the dense layer to be thin enough for high filtration rate while still providing sufficient strength through the multi-layer structure
Solution Approach 2:
The membrane uses a composite multi-layer structure combining different crystalline polymers with distinct properties. The first layer uses a crystalline polymer with specific melting point for strength, the second layer uses a different crystalline polymer with higher melting point and larger pores for flow rate, and the third layer uses the first polymer again for final filtration, creating a composite material system that balances strength and productivity
3Manufacturing precision
If pores with continuously changing diameters along thickness direction are formed to capture fine particles, then fine particle capture efficiency is improved, but service life decreases due to rapid clogging
Solution Approach 1:
The filtration process is segmented across three layers, so that fine particles are captured progressively rather than all at once in a single dense layer. The first layer captures some fine particles, the second layer with larger pores maintains flow and prevents rapid clogging, and the third layer provides final fine particle capture, distributing the clogging load and extending service life
Solution Approach 2:
Instead of relying on continuous pore diameter change in a single direction (thickness), the invention uses a multi-layer dimensional structure where pore diameters change in discrete steps across layers. This dimensional approach allows fine particle capture while maintaining open flow paths through the second layer, preventing rapid clogging and extending service life
4Ease of manufacture
If a single-layer structure is used to simplify manufacturing, then ease of manufacture is improved, but it is difficult to satisfy all required properties (high flow rate, no clogging, long service life, high strength) at desirable balance
Solution Approach 1:
The single-layer structure is segmented into three distinct layers, each with specific pore diameter and thickness characteristics optimized for particular functions. This segmentation allows the membrane to simultaneously achieve high flow rate (second layer), fine particle capture (first and third layers), and long service life (distributed clogging resistance), satisfying multiple performance requirements that cannot be met by a single-layer structure
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 membrane effectively captures fine particles, maintains high filtration rates, prevents clogging, and extends service life by optimizing pore structure and layer thickness, achieving improved durability and filtration efficiency.
Implementation Method 1
a plurality of pores each piercing through the laminate in a thickness direction thereof, wherein at least one layer in the laminate has a plurality of pores whose average diameter continuously or discontinuously changes along with a thickness direction of the laminate
Data Source
AI summary
A crystalline polymer microporous membrane, which contains: a laminate of two or more layers including a layer containing a first crystalline polymer and a layer containing a second crystalline polymer, the laminate having a plurality of pores each piercing through the laminate in a thickness direction thereof, wherein the first crystalline polymer has higher crystallinity than crystallinity of the second crystalline polymer, and the layer containing the first crystalline polymer has the maximum thickness thicker than the maximum thickness of the layer containing the second crystalline polymer, and wherein at least one layer in the laminate has a plurality of pores whose average diameter continuously or discontinuously changes along with a thickness direction of the laminate at least at part thereof.