Vapor deposition treated electret filter media
AssigneeHollingsorth & Vose Company
InventorsRichard E. Gahan, Wai Ming Choi
Life of this patent
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Abstract
A vapor phase treated 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 and mixtures thereof. Exemplary vapor phase deposition monomers include fluorinated monomers.
Claims62
An electret filter media comprising fibrous web having a substantially continuous uniform thickness polymer coating that is a vapor deposition formed condensed liquid monomer polymerized onto fibers that form the fibrous web.
An electret filter media comprising a fibrous web having a substantially uniform vapor deposition formed polymer coating thereon, the coating having a thickness in the range of about 50 Angstroms to 1 micron.
An electret filter media comprising a fibrous web having a substantially uniform polymer coating that is a vapor deposition formed condensed liquid monomer polymerized onto fibers that form the fibrous web, and having a melt processable charge stabilizing additive within said web, wherein said additive is present at a concentration in a range from about 0.01% to 20% by weight.
A respirator having a filter element comprising a fibrous web having a substantially continuous thickness uniform polymer coating that is a vapor deposition formed condensed liquid monomer polymerized by onto fibers that form the fibrous web.
A method for manufacturing an electret filter media comprising the steps of:
- providing a fibrous web;
- vaporizing an oleophobic and/or hydrophobic monomer;
- condensing the vaporized monomer onto to form a monomer coating on the fibers that form the fibrous web;
- exposing the monomer coating to sufficient energy to cause the monomer to polymerize, forming a polymer coated fibrous web;
- and
- treating the polymer coated fibrous web to form substantially permanent charge pairs or dipoles in the fibrous web.
An electret filter media, comprising a fibrous web having a substantially uniform vapor deposition formed polymer coating thereon, the fibrous web having an alpha value of at least about 20.
An electret filter media, comprising a fibrous web having a substantially uniform vapor deposition formed polymer coating thereon, the filter media has an alpha value above about 10 after a DOP test challenge loading over 200 mg of DOP at a face velocity of 16.4 fpm (85 lpm for 170 cm2 test area).
Dependencies are inferred from the claim text.