Air-filter filter material and method for producing filter material
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Solution Overview
Problem
Existing air-filter filter materials face challenges in achieving high particle collection performance and water repellency, particularly for particles in the 0.10 to 0.15 μm range, due to the use of fluorine-based water repellents that inhibit the formation of a mesh-like network of polyvinyl alcohol, and the presence of binder resins that hinder rapid drying and dispersibility.
Innovation Solution
A method involving the use of a polyvinyl alcohol aqueous solution containing a cationic surfactant and a water repellent, without binder resins, adhered to a support and dried at 140°C or higher, forms a mesh-like network of nanofiber in the support's pores, enhancing particle collection performance and water repellency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyvinyl alcohol and fluorine-based water repellent are used together, then water repellency is achieved, but particle collection performance deteriorates due to inhibition of mesh-like network formation
Solution Approach 1:
The patent removes binder resins from the polyvinyl alcohol aqueous solution to eliminate their harmful effect of inhibiting mesh-like network formation. By extracting the problematic component while retaining polyvinyl alcohol and water repellent, the solution achieves both water repellency and high particle collection performance through proper network structure formation.
Solution Approach 2:
The patent changes the chemical composition parameters of the aqueous solution by eliminating binder resins and optimizing the ratio of polyvinyl alcohol to water repellent. This parameter change allows the mesh-like network to form correctly while maintaining water repellency, resolving the contradiction between the two performance requirements.
2Productivity
If binder resins are added to enhance dispersibility, then fiber dispersibility is improved, but drying time increases and mesh-like network formation is hindered
Solution Approach 1:
The patent extracts and removes binder resins from the aqueous solution composition. This elimination prevents binder resins from interfering with mesh-like network formation while polyvinyl alcohol itself provides sufficient dispersibility and network-forming capability, enabling both rapid drying and proper network structure.
Solution Approach 2:
The patent allows polyvinyl alcohol to perform multiple functions simultaneously: it provides fiber dispersibility, forms the mesh-like network structure, and works synergistically with the water repellent. This self-service approach eliminates the need for binder resins and accelerates drying time.
3Reliability
If large amount of water repellent is added to achieve water repellency, then water repellency is improved, but particle collection performance decreases
Solution Approach 1:
The patent uses a controlled, partial amount of water repellent in the aqueous solution rather than large amounts. This partial action approach, combined with eliminating binder resins, allows sufficient water repellency to be achieved while preventing excess water repellent from interfering with mesh-like network formation and particle collection performance.
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 method produces an air-filter filter material with improved particle collection performance and water repellency, achieving a high PF value and low pressure loss, suitable for applications in clean rooms, clean benches, and other environments.
Implementation Method 1
a drying step of drying the polyvinyl alcohol aqueous solution adhered to the support in a wet state at 140° C. or higher
Implementation Method 2
by the polyvinyl alcohol aqueous solution being dried after completion of the drying step
Implementation Method 3
the polyvinyl alcohol aqueous solution contains a cationic surfactant and a water repellent
Implementation Method 4
pores, serving as fluid permeation paths, of the support is equipped with a mesh-like network of polyvinyl alcohol
Data Source
AI summary
A method for producing an air-filter filter material according to the present disclosure includes: an adhesion step of adhering a polyvinyl alcohol aqueous solution to a support, having fluid permeability, and bringing the support into a wet state; and a drying step of drying the polyvinyl alcohol aqueous solution adhered to the support in a wet state at 140° C. or higher; in the method, the polyvinyl alcohol aqueous solution contains a cationic surfactant and a water repellent and is free of binder resins other than polyvinyl alcohol, and pores, serving as fluid permeation paths, of the support is, by the polyvinyl alcohol aqueous solution being dried after completion of the drying step, equipped with a mesh-like network of polyvinyl alcohol.