A rigid, channel-framed, non-compressible, non-nestable, pleated air filter, comprising: a tightly-pleated air filter media comprised of a nonwoven fibrous web and with an upstream face and a downstream face, wherein the tightly-pleated air filter media comprises a plurality of upstream (and downstream) pleat tips and upstream (and downstream) pleat valleys, the tightly-pleated air filter media comprising a plurality of upstream (and downstream) linear bridging filaments that are at least substantially parallel to each other and are oriented at least substantially orthogonal to the pleat direction and are extrusion-bonded to at least some of the upstream (and downstream) pleat tips, and, a channel frame comprising four major frame portions, with each major frame portion being mounted on one of the four major edges of the pleated air filter media.

A substrate for use in a filter media including, for example, in a hydrocarbon fluid-water separation filter; methods of identifying the substrate; methods of making the substrate; methods of using the substrate; and methods of improving the roll off angle of the substrate. In some embodiments, the substrate includes a hydrophilic group-containing polymer or a hydrophilic group-containing polymer coating.

Disclosed herein, among other things, is an improved filter media construction that comprises multiple layers for improved odor control that can be used for vacuum cleaner air filtration cartridge applications. The filter media comprises anti-microbial ePTFE HEPA filter media to prevent mold growth. The filter media may also be used for air cleaner filtration, central air filtration for home and industrial buildings (HVAC), cleanrooms, and microelectronic devices. In an embodiment, the improved filter media construction comprises at least a PTFE layer, a bi-component layer, and a base layer. In an embodiment the PTFE layer comprises ePTFE. In an embodiment, the bi-component layer comprises non-woven polyethylene/polyethylene terephthalate (PE/PET). In yet another embodiment, the base layer comprises activated carbon. Other aspects and embodiments are provided herein.

A substrate for use in a filter media including, for example, in a hydrocarbon fluid-water separation filter; methods of identifying the substrate; methods of making the substrate; methods of using the substrate; and methods of improving the roll off angle of the substrate. In some embodiments, the substrate includes a hydrophilic group-containing polymer or a hydrophilic group-containing polymer coating.

A filtration media with improved filtration, strength, tear resistance and air permeability in the form of a relatively thin and lightweight wet-laid fibrous web that has a wet Mullen ratio of 60% to 80% to ensure that the media is flexible enough to be formed into a fluted structure, and strong enough to retain the fluted structure when wound into a roll and to permit further processing without the media becoming too brittle. The filtration media comprises a blend of cellulose and synthetic fibers having a weight percent of 81 wt % to 87 wt % of a weight of the media and a resin binder having a weight of 13 wt % to 19 wt % (preferably about 16 wt %) of the weight of the media.

A filter assembly includes a filter pad comprising fibers including natural, synthetic and/or hybrid fibers. A stabilizer frame formed of a non-metallic material may be imbedded in the filter pad. The stabilizer frame may be configured to provide support to the filter pad to maintain the filter pad in a generally flat configuration. In accordance with a particular embodiment, the filter pad may be comprised of at least first and second fibrous mats that are coupled together. In this embodiment, the stabilizer frame may be disposed between and coupled with the first and second fibrous mats.

A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 m when air containing the particles is passed through at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be in a filter pack or filter unit, and produced by integrating the films and the pre-collection member using heat lamination.

Filter elements are described. In an example embodiment, the filter element has a support framework and media defining a closed end and an open end. A non-circular radial seal is depicted, in an example. Variations for particular applications are described.

Fiber webs that may be used as filter media are provided. In some embodiments, the filter media may include multiple layers. Each layer may be designed to have separate functions in the filter media. For example, a first layer may be provided for improving dust holding capacity, a second layer for improving efficiency, and a third layer for providing support and strength to the media. By designing the layers to have separate functions, each layer may be optimized to enhance its function without negatively impacting the performance of another layer of the media.

A method of producing a copolymer of the present invention is a method of producing a specific copolymer and includes: a pure water production step of producing pure water having an electric conductivity of from 0.1 S/cm to 100 S/cm; a pure water transfer step of introducing the pure water into a reaction kettle for producing the copolymer through a transfer pipe using, as a material therefor, a resin or a substance forming a passive state in water; and a polymerization step of performing polymerization of the monomer (a), the monomer (b), and the monomer (c) in the reaction kettle, the pure water transfer step including setting the electric conductivity of the pure water at a site where the pure water is introduced from the transfer pipe toward the reaction kettle within a range of from 0.1 S/cm to 100 S/cm.