Method for producing electret fibers for enhancement of submicron aerosol filtration
AssigneeAlbany International Corp.
InventorSidney C. Stern
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Abstract
A method is provided for imparting a permanent electrostatic charge to polymeric fibers. Ions are implanted into the fibers in the presence of a strong electric field while the temperature is maintained above the glass transition temperature but below the melting temperature of the fibers. The method is particularly adapted for ion implantation into a fibrous filter mat. Carbonium ions formed by a corona discharge may be implanted into deep sites within the fibers.
Claims19
A method for imparting a permanent electrostatic charge to a polymeric fibrous filter mat, comprising the steps of:
- providing a first metallic base plate having a dielectric film thereon, said first plate being connected to ground;
- placing said polymeric fibrous filter mat in physical contact with said dielectric film;
- providing a second metallic base plate having a high density of corona discharge points extending therefrom, said second metallic base plate being connected to a high voltage source, and said corona discharge points being in close proximity to said filter mat;
- elevating the temperature of said plates and said filter mat to between the glass transition and melt temperatures of said polymeric filter mat;
- and
- applying a high voltage to said corona points to expose said filter mat to corona charging and an electric field, whereby the molecules within said polymeric fibrous filter mat become aligned so as to form dipoles and electrostatic charges are implanted within said filter mat due to said corona charging.
A method for imparting a permanent electrostatic charge to polymeric fibers, comprising the steps of implanting stable ions into said fibers in the presence of a strong electric field while said fibers are at a temperature above the glass transition temperature but below their melting temperature, whereby dipoles are formed in said fibers which are oriented in an array resembling the alignment of magnetic North and South poles in an electromagnetic field, and electrostatic charges are implanted in said fibers.
Dependencies are inferred from the claim text.