Filter Medium Solvent Bonding Nanofiber Air Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing filter media with nanofibers face challenges in achieving precise process control, fiber diameter variance, and undesirable air resistance due to bonding agents, which affect the bonding between fiber layers and substrate layers.
Innovation Solution
A method involving a substrate layer of nonwoven cellulose or synthetic polymer fibers with a deposited polymer fiber layer, where a solvent soluble to the fiber materials is applied to the substrate before deposition, allowing for electrospinning and material-fused connections at crossing points without forming flat fused areas, thereby maintaining fiber contours and improving air permeability and filter action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bonding agents are used to bond nanofiber layer with substrate layer, then bonding strength is improved, but air resistance increases due to sail-like projections
Solution Approach 1:
The invention extracts and eliminates the bonding agent from the system entirely. Instead of using external bonding agents, the patent employs electrostatic attraction between charged nanofibers and the substrate layer to achieve bonding without any additional bonding materials, thereby avoiding the formation of sail-like projections that increase air resistance
Solution Approach 2:
The invention introduces electrostatic field as an intermediary mechanism to facilitate bonding. The electrostatic attraction between charged nanofibers and the substrate layer serves as the mediating force that enables bonding without direct mechanical or chemical contact, thus avoiding the formation of protruding bonding structures
2Strength
If thermal calendering is used to solidify nanofibers, then bonding between layers is improved, but fiber diameter uniformity deteriorates
Solution Approach 1:
The invention replaces the mechanical thermal calendering system with an electrostatic field-based system. Instead of using mechanical pressure and heat to bond layers, the patent uses electrostatic attraction to hold nanofibers in place, preserving fiber diameter uniformity while achieving effective bonding
Solution Approach 2:
The invention changes the bonding mechanism from thermal-mechanical parameters to electrostatic parameters. By controlling voltage and charge distribution rather than temperature and pressure, the process maintains fiber integrity and diameter uniformity while achieving layer bonding
3Manufacturing precision
If electrospinning is used to deposit nanofibers, then fiber layer deposition is improved, but process control complexity increases
Solution Approach 1:
The invention makes the substrate layer multi-functional by giving it both mechanical support and electrostatic charging capabilities. The charged substrate serves dual purposes: as the structural base and as the electrostatic field source that guides and deposits nanofibers, simplifying the overall process control
Solution Approach 2:
The charged substrate layer performs self-service by automatically guiding and depositing nanofibers through electrostatic attraction without requiring complex external control systems. The electrostatic field naturally directs fiber deposition, eliminating the need for sophisticated process control mechanisms
4Strength
If bonding agents are used to bond fiber layers, then adhesion is improved, but material compatibility issues arise requiring different bonding agent systems
Solution Approach 1:
The invention extracts and eliminates bonding agents from the system, replacing them with electrostatic attraction. This universal electrostatic mechanism works across different material combinations without requiring material-specific bonding agent formulations, thereby improving material compatibility and versatility
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 a filter medium with high air permeability and filter efficiency, reducing material costs and eliminating the need for bonding agents, while ensuring robust adhesion between layers without water solubility issues, thus enhancing filtration performance.
Implementation Method 1
a solvent in which the material of the substrate layer and/or the material of the fiber layer is soluble is applied to the substrate layer
Implementation Method 2
nanofibers, by means of electrospinning, are deposited wet or moist onto a substrate layer
Data Source
AI summary
In a method for producing a filter medium, at least one substrate layer of a nonwoven comprising cellulose fibers and/or synthetic polymer fibers is provided and a fiber layer of polymer fibers is deposited on the at least one substrate layer. Prior to depositing the fiber layer, a solvent is applied to the at least one substrate layer, wherein a material of the substrate layer and/or a material of the fiber layer is soluble in the solvent. A filter medium produced by the method has material-fused connections at crossing points of the polymer fibers and/or cellulose fibers of the substrate layer with the polymer fibers of the fiber layer.