PTFE Electret Composition for Oil Mist-Resistant Charge Stability
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Solution Overview
Problem
Conventional electret filters face challenges in simultaneously achieving oil mist resistance and electric charge stability, particularly with the use of short-chain perfluoro compounds that comply with environmental regulations, and additives intended to enhance electrostatic charge often increase surface tension, exacerbating the elimination of electric charge when exposed to oil mist.
Innovation Solution
The development of an electret using polytetrafluoroethylene with a melting point between 35°C and 320°C, combined with hindered amine-based or triazine-based additives, and a hindered phenol-based additive, deposited on a carrier using methods like solution or vapor deposition, to enhance oil repellency and electrostatic charge stability without relying on PFOA or PFOS compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If short-chain perfluoro compounds are used to improve oil mist resistance, then oil repellency is enhanced, but electric charge stability deteriorates
Solution Approach 1:
The patent changes the molecular structure parameter of fluorinated compounds by specifying carbon chain length (C4-C10) and functional group composition (carboxylic acid, alcohol, or ether groups). This parameter optimization achieves the balance between oil mist resistance and electric charge stability by preventing both excessive charge elimination and bioaccumulation issues associated with longer chain compounds like PFOA and PFOS.
2Quantity of substance
If additives are added to enhance electrostatic charge, then electric charge quantity increases, but surface tension increases causing faster charge elimination when exposed to oil mist
Solution Approach 1:
The patent optimizes the surface tension parameter by carefully selecting fluorinated compounds with specific carbon chain lengths (C4-C10) and functional groups. This parameter control ensures that while electrostatic charge can be maintained, the surface tension remains low enough to prevent rapid charge elimination when exposed to oil mist, resolving the contradiction between charge quantity and oil mist resistance.
3Stability of the object's composition
If conventional electret materials are used to achieve electric charge stability, then charge stability is maintained, but oil repellency is insufficient
Solution Approach 1:
The patent creates a composite material system by combining polyolefin or polyester base materials with specifically selected fluorinated compounds (containing C4-C10 chains and carboxylic acid, alcohol, or ether groups). This composite approach integrates the charge stability of conventional electret materials with the enhanced oil repellency provided by the fluorinated additives, resolving the contradiction between these two properties.
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
This approach results in an electret with improved oil repellency, oil mist resistance, and sustained electrostatic charge stability, suitable for use in filters for dust respirators and air conditioning elements, while avoiding the environmental concerns associated with PFOA and PFOS.
Implementation Method 1
deposited on a carrier using methods like solution or vapor deposition
Implementation Method 2
a method for imparting a long life electrostatic charge to an insulating material. Particularly, the latter technique has widely been employed for an electret filter since there is no need to use energy such as an external power source
Implementation Method 3
a method for imparting an electrostatic charge to a filter, or a combination of both of them. For examples of the method for imparting an electrostatic charge to a filter, there is known a method of disposing a filter between electrodes and causing dielectric polarization at the time of ventilation
Implementation Method 4
the carrier contains 0.01 to 15.0 wt. % of at least one of a hindered amine-based additive and a triazine-based additive
Implementation Method 5
a method for imparting an electric charge to object particles to be collected, a method for imparting an electric charge to a filter, or a combination of both of them
Data Source
AI summary
[Problems]An object of the present invention is to provide an electret with an initial increased electrostatic charge quantity and suppressed attenuation of electrostatic charge to liquid particles.[Means for solving]The electret is obtained by depositing polytetrafluoroethylene having a melting point of 35° C. or higher and 320° C. or lower on a carrier and imparting an electrostatic charge to at least one of the carrier and the polytetrafluoroethylene.