Filter media with charge stabilizing and enhancing additives
AssigneeHollingsworth & Vose Company
InventorStephen Cox
Life of this patent
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Abstract
Electret filter media having an increased electrostatic charge that is substantially maintained in the presence of heat are provided. In one exemplary embodiment, the filter media includes a melt processable charge enhancing additive, such as a fatty acid amide, and a melt processable charge stabilizing additive, such as a fatty acid metal salt. The charge enhancing additive is particularly effective to increase or enhance the electrostatic charge of the filter media when a charge is imparted thereto, and the charge stabilizing additive is particularly effective to stabilize the charge such that, when the filter media is subjected to a heat treatment, the enhanced electrostatic charge is substantially maintained.
Claims32
A filter media, comprising a meltblown electret polymer fiber web having a melt processable fatty acid amide present within the web and effective to enhance the level of electrostatic charge, and a melt processable fatty acid metal salt present within the web and effective to maintain the electrostatic charge when the filter media is subjected to heat.
A filter media, comprising an electret web of fibers, the fibers comprising a blend of a polymer, a fatty acid amide, and a metal stearate, the fatty acid amide being present within the web at a concentration in the range of about 0.5% to 11% by weight, and the metal stearate being present within the web at a concentration in the range of about 0.1% to 20% by weight.
A filter media, comprising a meltblown electret polymer fiber web having a basis weight of about 60 g/m and having a melt processable ethylene bis-stearamide present within the web at a concentration in the range of about 0.5% to 11% by weight, and a melt processable magnesium stearate present within the web at a concentration in the range of about 0.1% to 20% by weight.
A meltblown electret web of polymer fibers, the polymers fibers comprising a polymer, about 0.5% to 11% by weight of a fatty acid amide, and about 0.1% to 20% by weight of a fatty acid metal salt, the fatty acid amide and the fatty acid metal salt being dispersed in the polymer as a melt blend additive.
A method for forming a filter media, comprising:
- extruding a polymer composition containing a polymer, a fatty acid amide, and a fatty acid metal salt to form a meltblown polymer fiber web;
- and
- imparting an electric charge to the meltblown polymer fiber web to form a meltblown electret polymer fiber web.
Dependencies are inferred from the claim text.