Electrically charged nonwoven fabric, filtration material including same, and method for producing electrically charged nonwoven fabric
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Solution Overview
Problem
Conventional electrically charged nonwoven fabrics, used in filtration materials, lack heat resistance and flame retardancy, making them unsuitable for high-temperature applications and causing handleability and waste treatment issues.
Innovation Solution
An electrically charged nonwoven fabric predominantly composed of an amorphous polymer, produced using the melt blown or spunbonding method and subjected to corona discharge or hydro-charging, achieving high surface charge density and long-lasting collection efficiency even under high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polypropylene fiber is used for electrically charged nonwoven fabric, then collection efficiency is improved, but heat resistance deteriorates
Solution Approach 1:
The patent changes the material parameter from polypropylene fiber to heat-resistant fiber, which has fundamentally different thermal properties. This parameter change enables the nonwoven fabric to maintain both electrical charge for collection efficiency and thermal stability for heat resistance, resolving the contradiction between these two properties.
2Temperature
If glass fiber is used for heat-resistant filter, then heat resistance is improved, but handleability deteriorates
Solution Approach 1:
The patent uses composite materials by combining heat-resistant fiber with electroactive fiber in a nonwoven fabric structure. This composite approach provides both heat resistance from the heat-resistant fiber and good handleability from the synthetic fiber components, avoiding the skin irritation and waste treatment issues associated with glass fiber while maintaining thermal performance.
3Reliability
If polypropylene fiber is used for electrically charged nonwoven fabric, then collection efficiency is improved, but flame retardancy deteriorates
Solution Approach 1:
The patent changes the material composition parameter from polypropylene to heat-resistant fiber, which inherently possesses better flame retardancy properties. This material substitution maintains the electrical charge capability needed for collection efficiency while providing inherent fire resistance, eliminating the need for additional flame retardant treatments.
4Temperature
If glass fiber is used for heat-resistant filter, then heat resistance is improved, but waste treatment problems worsen
Solution Approach 1:
The patent employs composite materials using heat-resistant fiber combined with synthetic electroactive fiber, creating a nonwoven fabric that is both heat-resistant and easier to handle and dispose of than glass fiber. This composite structure maintains thermal performance while improving waste treatment characteristics, as the synthetic fiber components are more manageable in terms of disposal and recycling.
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 resulting filtration material exhibits low pressure loss, excellent collection efficiency, and improved heat resistance and flame retardancy, with enhanced handleability and reduced waste treatment concerns.
Implementation Method 1
electrically charged by a method such as the corona discharge method or the hydro-charging method
Implementation Method 2
electrically charged by a method such as the corona discharge method or the hydro-charging method
Implementation Method 3
electrically charged nonwoven fabrics have been typically used, which are nonwoven fabrics formed of polypropylene fiber electrically charged
Data Source
AI summary
Use of an electrically charged nonwoven fabric that is made of a fiber predominantly composed of an amorphous polymer provides a novel filtration material having improved performance compared to that of conventional filtration materials, and having excellent heat resistance and excellent flame retardancy as well as an electrically charged nonwoven fabric for use in the filtration material. It is preferable that the surface charge density is greater than or equal to 1.times.10.sup.-10 coulomb/cm.sup.2. It is preferable that the collection efficiency for collecting a dust particle with a particle diameter of 1 .mu.m flowing at a fabric-passing velocity of 8.6 cm/second is greater than or equal to 40%, the QF value is greater than or equal to 0.05, and the decrement of the dust-particle collection efficiency after being allowed to leave at 100.degree. C. for 24 hours is less than or equal to 10%.