Charge stabilized electret filter media
AssigneeHollingsowrth & Vose Company
InventorsNorman Lifshutz, Richard E. Gahan, Graham C. Stevens
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Abstract
An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides, oleophobic fluorochemical surfactants, and mixtures thereof.
Claims6
A filter media comprising a meltblown electret polypropylene fiber web having a melt processable nonionic oleophobic fluorochemical additive compound selected from the group consisting of stearate esters of perfluoroalcohols, fluorochemical urethane derivatives, and fluorochemical oxazolidinones, the compound being present within the web at a concentration in the range of about 0.2 to 3.5% by weight to achieve sustained electret filtration enhancement.
A respirator having a filter element comprising a meltblown electret polypropylene fiber web having a melt processable nonionic oleophobic fluorochemical additive compound selected from the group consisting of stearate esters of perfluoroalcohols, fluorochemical urethane derivatives, and fluorochemical oxazolidinones, the compound being present within the web at a concentration in the range of about 0.2 to 3.5% by weight to achieve sustained electret filtration enhancement.
Dependencies are inferred from the claim text.