Low-Crystallinity Pleated Filter Media for Stable Folds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
State-of-the-art pleated filters made from thermoplastic polymers, such as PET or PP, suffer from unstable fold structures due to high crystallinity, leading to rapid deformation and loss of dimensionality, which limits their stability and production speed.
Innovation Solution
Producing filter media with a low proportion of crystalline areas by controlling the cooling process of the polymer melt after extrusion, using techniques like dynamic differential calorimetry to determine and adjust the crystallinity, results in a crease recovery angle of less than 90°, ensuring stable folds and improved dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoplastic polymer filter media are used with high crystallinity to ensure strength and restoring forces, then the filter media gain mechanical stability, but the fold structure disappears quickly after folding due to high crease recovery angle (105-180°)
Solution Approach 1:
The patent changes the crystallinity parameter of the thermoplastic polymer from high (traditional) to low (less than 50% crystalline areas). This parameter change reduces the crease recovery angle to below 90°, allowing folds to remain stable while maintaining sufficient mechanical strength through optimized polymer composition and structure.
2Stability of the object's composition
If heat treatment is applied before folding to retain fold structure, then the fold structure becomes stable, but production speed is limited and equipment complexity increases
Solution Approach 1:
The patent incorporates the fold stability function directly into the polymer material itself during manufacturing, eliminating the need for separate preheating steps. The low-crystallinity polymer structure is created in advance through controlled cooling after extrusion, so that folds are retained without requiring subsequent heat treatment equipment or processes.
3Stability of the object's composition
If chemical binders are used to increase wrinkle stability in paper media, then fold stability is improved, but the media can no longer be recycled due to chemical content
Solution Approach 1:
The patent extracts and eliminates chemical binders from the filter media composition. Instead of using chemicals to stabilize wrinkles, the invention uses a physical approach with low-crystallinity thermoplastic polymers that naturally retain folds without chemical additives, thereby maintaining recyclability while achieving fold stability.
4Stability of the object's composition
If complex heat treatment equipment is used to influence fold structure, then fold stability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent enables the polymer material to self-stabilize folds through its inherent low-crystallinity structure. The material itself provides the stability function without requiring external heat treatment equipment, simplifying the manufacturing process and reducing device complexity while maintaining fold structure stability.
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 reduced crystallinity in the filter media leads to enhanced fold stability, increased production speed, and extended filter life, allowing for higher fold densities and increased filter area without the need for preheating, thus overcoming the limitations of existing technologies.
Implementation Method 1
the polymer is given time to crystallize, i.e. the individual polymer chains are present in a spatially ordered manner
Implementation Method 2
the cooling takes place in such a way that the polymer is given time to crystallize
Data Source
Figure 1
Figure 2
AI summary
A filter medium consists of extruded nonwoven material, extruded nonwoven material and/or thermoplastic polymer filament, or filament and/or fiber of polymer or polymer mixtures having crystallinity of less than 50%. The polymer is polyester, polyolefin, thermoplastic polylactide or polystyrene.