Composite Polyolefin Filter Material for High Collection and Low Pressure Loss
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Solution Overview
Problem
Conventional meltblown nonwoven fabrics used as filter materials suffer from low elastic stress, leading to breakage under external forces and a trade-off between high particle collection efficiency and low ventilation resistance.
Innovation Solution
A filter material composed of fibers containing polyolefin resins with different melt flow rates, achieving a combined tensile elongation of 100% or more and a quality factor of 1.8 or higher, enhanced by electret treatment and additives like hindered amine based compounds and magnesium stearate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional meltblown nonwoven fabrics are used, then fine fibers can be produced with simple process, but the fabric has low elastic stress and breaks easily under external forces
Solution Approach 1:
The invention uses a composite resin composition containing polypropylene resin and polyethylene resin in specific proportions (polypropylene: 70-95 wt%, polyethylene: 5-30 wt%). This composite material combines the fine fiber production capability of polypropylene with the flexibility and elasticity of polyethylene, achieving both ease of manufacture and improved strength/elasticity without breaking under external forces
Solution Approach 2:
The invention optimizes specific parameters including resin composition ratios, melt flow rates, and processing conditions to achieve the desired balance between manufacturability and mechanical properties. By controlling the polyethylene content (5-30 wt%) and using resins with specific melt flow rates, the fabric gains sufficient elastic stress while maintaining the simplicity of the meltblowing process
2Measurement precision
If single fibers are made with finer denier to achieve high particle collection efficiency, then collection efficiency improves, but the nonwoven fabric becomes more susceptible to collapse and ventilation resistance increases
Solution Approach 1:
The invention changes the physical and chemical parameters of the fiber material by using a specific resin composition with polyethylene added to polypropylene. This modification allows the fine fibers to maintain their small diameter for high collection efficiency while the polyethylene component provides flexibility that prevents fabric collapse, thereby maintaining low ventilation resistance
Solution Approach 2:
The composite resin system enables fine fibers to be produced that combine the filtration efficiency of small diameter with the structural integrity provided by polyethylene's flexibility, resolving the contradiction between collection efficiency and ventilation resistance
3Measurement precision
If electret treatment is applied to achieve high particle collection efficiency, then collection efficiency improves, but the fabric remains susceptible to breakage due to insufficient elasticity
Solution Approach 1:
The invention applies electret treatment to the composite nonwoven fabric made from polypropylene and polyethylene resins. The polyethylene component provides the necessary elasticity and flexibility to prevent breakage during electret treatment and subsequent handling, while the electret treatment imparts high particle collection efficiency through electrostatic attraction
Solution Approach 2:
The invention optimizes the resin composition parameters to achieve sufficient elasticity before electret treatment, ensuring the fabric can withstand the treatment process and subsequent use without breaking, while still achieving high collection efficiency through the electret effect
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 filter material exhibits high collection efficiency, low pressure loss, and high elongation, resisting breakage under external forces, suitable for thin filters and those combined with adsorbents.
Implementation Method 1
attempts have been made to simultaneously achieve both high particle collection efficiency and low ventilation resistance by electretizing the nonwoven fabric, thereby utilizing electrostatic forces in addition to physical mechanisms for particle capture
Data Source
AI summary
An object of the present invention is to provide a filter material and a filter that exhibit both high collection efficiency and low pressure loss, as well as high elongation. A filter material comprising a fiber sheet composed of fibers containing a plurality of polyolefin resins having different melt flow rates (MFRs), wherein a sum of a tensile elongation in a MD direction and a tensile elongation in a TD direction of the fiber sheet is 100% or more, and wherein a quality factor value calculated by the following equation is 1.8 or more: Quality factor value = -Ln ((100 - Collection efficiency [%]) / 100) / Pressure loss [mmAq]