Microfiber Liquid Filter Medium for Low Weight and High Strength
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Solution Overview
Problem
Conventional liquid filters face issues with high weight per unit, low strength, and short life due to large and non-uniform pore sizes, which lead to increased pressure drop and blockages, and existing solutions like heat treatment and nozzle size reduction do not satisfactorily address these problems.
Innovation Solution
A filter medium with a main fiber diameter of 4.0 µm or less and a binder fiber diameter of 3.0 µm or less, both with aspect ratios of 100 to 2,500, and a weight proportion of 10 to 50 wt%, combined with a wet-laid nonwoven fabric structure, achieving a low weight per unit while maintaining high strength and collectability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a nonwoven fabric with large weight per unit is produced and compressed through heat treatment to reduce pore size, then collectability improves, but weight per unit increases and pressure drop increases
Solution Approach 1:
The invention changes the fundamental parameter of fiber diameter to achieve small and uniform pore sizes without compression. By using microfibers with diameter of 4.0 μm or less and aspect ratio of 100 to 2,500, the patent achieves pore size uniformity intrinsically through fiber selection rather than through compressive deformation, thereby avoiding the weight increase associated with traditional heat treatment methods.
Solution Approach 2:
Instead of using large fibers and compressing them to reduce pore size (traditional approach), the invention inverts the approach by directly using small-diameter microfibers to achieve the desired pore structure. This inversion eliminates the need for compression and heat treatment, thereby maintaining low weight per unit while achieving high collectability.
2Manufacturing precision
If a nonwoven fabric with large weight per unit is compressed to reduce pore size, then collectability improves, but pressure drop increases and filter life decreases
Solution Approach 1:
The invention changes the fiber diameter parameter to 4.0 μm or less and aspect ratio to 100 to 2,500, which inherently creates small and uniform pore sizes without requiring compression. This parameter change achieves high collectability while maintaining open pore structures that prevent dust particle blockage, thereby extending filter life and maintaining low pressure drop.
3Manufacturing precision
If the meltblowing nozzle size is reduced to make pore size small, then collectability may improve, but the results are not yet satisfactory and manufacturing complexity increases
Solution Approach 1:
The invention extracts the pore size control function from the nozzle geometry and transfers it to the fiber diameter characteristics. By using microfibers with diameter of 4.0 μm or less and appropriate aspect ratios, the patent achieves small and uniform pore sizes without requiring complex or miniaturized nozzle designs, thereby simplifying the manufacturing process while achieving high collectability.
4Manufacturing precision
If electrostatic spinning method is used to produce microfiber filter medium, then pore size can be small, but strength of the filter medium is low and workability is extremely low
Solution Approach 1:
The invention uses a composite nonwoven fabric structure combining microfibers (diameter 4.0 μm or less, aspect ratio 100 to 2,500) with binder fibers (diameter 3.0 μm or less, aspect ratio 100 to 2,500) at weight proportions of 10 to 50 wt%. This composite structure provides both the small pore sizes needed for high collectability and the mechanical strength required for good workability, overcoming the limitations of electrostatic spinning alone.
Data Source
Figure 1~2
AI summary
The invention addresses the problem of providing a filter medium for a liquid filter, which has a low weight per unit and yet has high strength, high collectability, and a long life, and also a liquid filter. As a means for resolution, using a main fiber having a fiber diameter of 4.0 µm or less and an aspect ratio of 100 to 2,500 and a binder fiber having a fiber diameter of 3.0 µm or less and an aspect ratio of 100 to 2,500, a filter medium for a liquid filter in which the weight proportion of the binder fiber relative to the weight of the filter medium is 10 to 50 wt%, and the weight per unit is within a range of 5 to 80 g/m2, and also a liquid filter are obtained.