A nonwoven fabric, including fibers, in which the fibers have an elongational viscosity, as measured under conditions at an elongational strain rate of 2.5×10.sup.2 (1/s) and a temperature of 160° C., of from 430 Pa.Math.s to 1200 Pa.Math.s, and a ratio of the elongational viscosity (Pa.Math.s) to a shear viscosity (Pa.Math.s) of the fiber, as measured under conditions at a shear strain rate of 2.5×10.sup.2 (1/s) and a temperature of 160° C., is from 35 to 65.

The invention relates to a fibrous nonwoven, in particular for a filter medium, having a first layer, wherein at least one single-piece fiber strand of said first layer has a first fiber portion and a second fiber portion in the longitudinal direction, and wherein the fiber strand has a thickening substantially in said second fiber portion.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The additives are substituted heterocyclic thiolate salts. The heterocyclic thiolate salt has 2 nitrogen groups and a third group that may be an NH, N—NH.sub.2, O, or S group. The substituent group is an aromatic or heterocyclic aromatic group. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

The disclosure provides improved vent filters useful in single-use in-line transfusion systems. In a first aspect, the disclosure provides filter comprising (i) a layer comprising a fluoropolymer membrane and (ii) a layer comprising at least two air-permeable thermoplastic polymeric layers, the air-permeable thermoplastic polymeric layers comprised of a first polymeric layer and a second polymeric layer, wherein the first polymeric layer is in bonded contact with the fluoropolymer membrane, possesses a melting point of about 95° C. to about 180° C., and wherein the second polymeric layer is in bonded contact with the first polymeric layer and has a melting point of about 220° C. to about 265° C. These filters exhibit excellent bonding strength between the various layers while preserving a considerable amount of the original fluoropolymer membrane air flux.

A gas filtering medium is composed of hydrophobic polyester fiber as from 20-80% by total weight of textile fibers and 80-20% by total weight of hydrophilic textile fibers and a microfibrillated cellulose fiber in a weight/weight ratio of 1.5-8.5/100 parts by weight of total textile fiber.

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.

Articles and methods involving filter media are generally provided. In certain embodiments, the filter media includes at least a first layer, a second layer, and an adhesive resin positioned between the first layer and the second layer. In some embodiments, the first layer may be a pre-filter layer or a support layer. The second layer may, for example, comprise fibers formed by a solution spinning process and/or may comprise fine fibers. In some embodiments, the adhesive resin may be present in a relatively low amount and/or may have a low glass transition temperature. The filter media as a whole may have one or more advantageous properties, including one or more of a high stiffness, a high bond strength between the first layer and the second layer, a high gamma, and/or a low increase in air resistance after being subjected to an IPA vapor discharge. The filter media may be, for example, a HEPA filter and/or an ULPA filter.

Provided is a filter medium. A filter medium according to an embodiment of the present invention comprises: a first porous support body which has been electrostatically treated; and a nanofiber web which is disposed on one surface of the first support body and formed by accumulating nanofibers. Accordingly, excellent air filtering efficiency is obtained even for fine dust of PM 2.5 or below, and furthermore, deterioration in air filtering efficiency may be prevented or minimized even when usage is extended for a long period of time. Therefore, the filter medium and the composite filter according to an embodiment of the present invention can be widely utilized as media of filters for various air filtering devices.

It is provided that a layered body having excellent absorption speeds of fuel and the like to the filter media. A layered body comprising a first base material and a second base material, wherein the first base material and the second base material are adhered to each other via an adhesive, the first and second base materials each contain a phenol-based resin and an aliphatic hydrocarbon detected during a retention time of 12.0 to 30.0 minutes under pyrolysis-gas chromatography mass spectrometry (PY-GC/MS), and the adhesive contains 65 mol % or more of a butylene terephthalate unit and 5 mol % or more of a butylene isophthalate unit, and has an acid value of not larger than 100 eq/ton, a glass transition temperature of −10 to 60° C., and a specific gravity of not less than 1.20.

Metal nanoparticle agglomerates may convey biocidal activity to surfaces upon which they are deposited and become adhered, such as various air filtration media. Air filtration media may comprise a plurality of fibers having a plurality of metal nanoparticle agglomerates adhered thereto. The metal nanoparticle agglomerates may comprise a plurality of fused, partially fused, or unfused metal nanoparticles that are associated with one another upon a surface of the plurality of the fibers. Suitable metal nanoparticles for promoting biocidal activity against various pathogens, such as viruses and bacteria, may include copper nanoparticles and/or silver nanoparticles. Masks, inline filters, and air filtration systems may incorporate the air filtration media.