Filter media having a relatively small pore size and related components, systems, and methods associated therewith are provided. The filter media may include a fibrous efficiency layer, a fibrous support layer, and a third layer adjacent to the efficiency layer. The efficiency layer may impart a relatively homogeneous pore structure to the filter media without adding substantial bulk to the filter media. The support layer may promote the homogeneity of the pore structure. For example, the support layer may prevent and/or minimize defects in the relatively thin efficiency layer that may result from manufacturing and/or processing. The third layer may serve to impart beneficial filtration (e.g., efficiency, dust holding capacity) and/or non-filtration (e.g., layer protection) properties to the filter media without adversely affecting one or more properties of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve liquid filtration, amongst other applications.

Filter media comprising non-woven fiber webs having one or more advantageous physical properties are generally described. In some embodiments, a filter media and/or non-woven fiber web described herein comprises a combination of fibers that results in enhanced physical properties. For example, the non-woven fiber web may comprise a combination of fiber types that is advantageous, such as a combination comprising fibrillated fibers, glass fibers, and/or binder fibers. In some cases, the filter media and/or non-woven fiber web comprising the combination of fibers may be formed into undulations (e.g., by a creping and/or microcreping process) to further enhance the physical properties of the filter media and/or non-woven fiber.

A spunbond non-woven fabric includes a thermoplastic continuous filament. Bending resistance in a machine direction of the spunbond non-woven fabric is 40 mN or more and 80 mN or less, the spunbond non-woven fabric includes a nonbonded projected part and a bonded recessed part, and in a non-woven fabric cross-section, a thickness from one surface to another surface of the projected part is determined to be t.sub.A, a thickness from one surface to another surface of the recessed part is determined to be t.sub.B, and respective distances from one surface of the projected part to one surface of the recessed part are determined to be t.sub.C and t.sub.D (t.sub.C<t.sub.D), and the spunbond non-woven fabric has a relation represented by formulas (1) and (2) below:

0.5≤1−t.sub.B/t.sub.A<1.0   (1)

0.65<t.sub.C/t.sub.D<1.0   (2).

A nanofiber nonwoven product is disclosed which comprises a polyamide with a relative viscosity from 2 to 330, spun into nanofibers with an average diameter of less than 1000 nanometers (1 micron). In general, the inventive products are prepared by: (a) providing a polyamide composition, wherein the polyamide has a relative viscosity from 2 to 330; (b) melt spinning the polyamide composition into a plurality of nanofibers having an average fiber diameter of less than 1 micron, followed by (c) forming the nanofibers into the product.

Compositions and articles comprising a non-woven matrix for use as anti-microbial filters are provided. In some embodiments, the non-woven matrix comprises nanofibers suitable for capturing a droplet comprising a microbe (e.g. a virus particle). In some embodiments, the non-woven matrix comprises a biocide suitable for reducing propagation and/or inactivating a microbe.

A coalescence filter for purifying a fluid which contains a carrier and at least one liquid contaminant by coalescing of the at least one contaminant, where the coalescence filter includes an inlet for supplying the fluid to a filter element present in the coalescence filter, where the filter element includes a primary coalescence medium which is provided for coalescing of the at least one contaminant in the primary coalescence medium during the displacement of the fluid through the primary coalescence medium. The coalescence filter further includes an outlet for discharging the coalesced contaminant from the filter element, where the primary coalescence medium comprises at least one layer of a porous material, where the primary coalescence medium has a total thickness of at least 3.5 mm.

A filter material for use in fuel-water separation has a particle filtration layer and a coalescing layer downstream of, and coupled to, the particle filtration layer. The particle filtration layer is substantially constructed of binder fibers and media fibers. The coalescing layer has at least 70% glass fibers by weight. As another example, a filter material for liquid fuels has a particle filtration layer and a coalescing layer downstream of the particle filtration layer. The particle filtration layer has binder fibers and media fibers and is substantially free of meltblown materials. The ratio of air permeability of the particle filtration layer to air permeability of the coalescing layer ranges from about 3:1 to about 15:1.

The present invention relates to a filter medium (10) for air and/or water cleaning, comprising a semiconductor photocatalytic material (14) and a light energy source (15) for radiating light provided to activate photocatalytic reactions of the semiconductor photocatalytic material (14). The light energy source (15) is configured as a support (16) for the semiconductor photocatalytic material (14). The filter medium (10) can be incorporated into a filter unit (100).

The purpose of the present invention is to provide an electret fiber sheet that has high collection performance and that is suitably used in an air filter, etc. The present invention is an electret fiber sheet configured from polyolefin-based resin fibers comprising a polyolefin-based resin composition containing a high-crystalline polyolefin resin and a low-crystalline polyolefin resin, wherein the mass ratio of the low-crystalline polyolefin resin in the polyolefin-based resin composition is 0.5-10 mass % (inclusive) relative to the total mass of the high-crystalline polyolefin-based resin and the low-crystalline polyolefin resin, and a hindered-amine-based compound is included in the electret fiber sheet in an amount of 0.1-5.0 mass % (inclusive).

A pleated multilayer air filter assembly including a primary filtration layer and a prefilter layer that are bonded to each other and are co-pleated with each other. The primary filtration layer includes meltblown electret fibers. The prefilter layer includes meltspun, spunbonded electret fibers that comprise a radially outer surface comprising polymethylpentene. The ratio of Effective Fiber Diameter of the fibers of the primary filtration layer to Effective Fiber Diameter of the fibers of the primary filtration layer is at least 1.5.