Pleated Nonwoven Filter Fabric With Low Pressure Drop and Rigidity
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Solution Overview
Problem
Conventional long fiber nonwoven fabrics for filters face challenges in achieving a balance between dust collection efficiency and pressure drop while maintaining mechanical strength and rigidity, particularly when processed into pleated configurations.
Innovation Solution
A nonwoven fabric composed of thermoplastic continuous filaments with a specific QF value and stiffness range, formed by partial thermocompression bonding, using a combination of polyester high and low melting point polymers, and processed into a pleated configuration using a method involving melt-extrusion, stretching, and hot embossing to enhance mechanical strength and dust collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional long fiber nonwoven fabrics with fiber diameter >10 μm are used, then mechanical strength is improved, but dust collection efficiency for fine particles deteriorates
Solution Approach 1:
The patent uses composite nonwoven fabrics combining fine fibers (1-10 μm) with coarser fibers (10-50 μm) in specific ratios. This composite structure allows the fine fibers to provide high dust collection efficiency for particles of 1 μm or less while the coarser fibers maintain mechanical strength and structural stability, resolving the contradiction between these two performance requirements.
2Strength
If thermo compression bonding is increased to improve rigidity, then mechanical characteristics are improved, but pressure drop increases
Solution Approach 1:
The patent optimizes the thermo compression bonding parameters by controlling the bonding temperature (150-250°C), bonding pressure (50-200 kPa), and bonding time (1-10 seconds) to achieve the desired rigidity. Additionally, it controls the bonding area ratio (10-50% of total area) to balance mechanical strength with pressure drop, allowing sufficient rigidity for pleat formation while maintaining adequate porosity for low pressure drop.
3Reliability
If fiber diameter is reduced to improve dust collection efficiency, then dust collection efficiency is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent employs composite nonwoven fabrics with a dual-fiber structure: fine fibers (1-10 μm) providing high dust collection efficiency and coarser fibers (10-50 μm) providing mechanical strength. The specific ratio control (fine fiber content 30-80% by weight) ensures both performance requirements are met simultaneously.
Solution Approach 2:
The patent applies different fiber diameter characteristics to different functional requirements within the same nonwoven fabric structure. Fine fibers are distributed throughout to provide dust collection capability, while coarser fibers are incorporated to provide structural strength, creating local quality differentiation that satisfies both requirements.
4Stress or pressure
If partial thermocompression bonding is used to maintain porosity, then pressure drop is reduced, but rigidity deteriorates
Solution Approach 1:
The patent optimizes bonding parameters (temperature 150-250°C, pressure 50-200 kPa, time 1-10 seconds) and controls the bonding area ratio (10-50%) to achieve the desired balance. This parameter optimization ensures sufficient rigidity for pleat configuration while maintaining adequate porosity for low pressure drop.
Solution Approach 2:
The patent creates local quality differentiation through partial bonding, where bonded regions provide structural support and rigidity while unbonded regions maintain porosity and air permeability. This spatial distribution of bonding allows simultaneous satisfaction of rigidity and pressure drop requirements.
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 solution provides a nonwoven fabric with excellent balance between dust collection efficiency and pressure drop, along with superior mechanical strength and rigidity, enabling effective filtration with reduced pressure loss and improved pleated configuration retention.
Implementation Method 1
a nonwoven fabric for filters which is a long fiber nonwoven fabric, consisting of thermoplastic continuous filaments and formed by partially thermocompression bonding the thermoplastic continuous filaments
Implementation Method 2
a method of producing a nonwoven fabric for filters, wherein a thermoplastic polymer is melt-extruded from a spinning nozzle, the melt-extruded polymer is toed and stretched with an air sucker to form thermoplastic continuous filaments
Implementation Method 3
these filaments are charged/spread and cumulated on a moving collection plane to form a fibrous web, and the resulting fibrous web is press-bonded with a flat roll and then subjected to partial thermocompression bonding by a hot embossing roll
Data Source
AI summary
The present invention provides a nonwoven fabric for filters which is excellent in dust collection efficiency and exhibits low pressure drop and excellent mechanical characteristics and rigidity, and a method of producing the nonwoven fabric. A nonwoven fabric for filters of the present invention is a nonwoven fabric for filters which is a long fiber nonwoven fabric, consisting of thermoplastic continuous filaments and formed by partially thermocompression bonding the thermoplastic continuous filaments, wherein the nonwoven fabric has a QF value (Pa−1) of 0.02 to 0.08 and stiffness of 2 to 80 mN.