Nonwoven fabrics are provided that include a first meltblown layer, in which the first meltblown layer comprises a first polymeric material including (i) a first polymer component and (ii) optionally one or more first additives. The first polymer component comprises a first recycled-polypropylene (rPP).

An improved technology for inactivation of viruses, for example the SARS-CoV-2 virus that is causing the Covid-19 pandemic, is described. The technology can include a device that includes a substrate coated in a polymer that is infused with a pathogen inactivating material. In various embodiments, at a given time, a portion of the pathogen inactivating material is exposed to the environment, and the device is configured to periodically or intermittently expose additional pathogen inactivating material to the environment. For example, the polymer can be ablative or sacrificial.

Provided herein are filter media structures having antimicrobial and/or antiviral properties. In particular, the present disclosure describes filter media structures having a first layer with an electret web and a second layer that demonstrates biological-reducing properties. In some cases, the first layer is formed from polypropylene (e.g., spunbond) and the second layer is formed from a plurality of fibers of a polyamide composition (e.g., meltblown).

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.

Nanofiber filter media ribbons are flexible elongate strips of polymeric material having a surface on which is formed an array of nanofibers. Ribbons are formable into woven or non-woven mats. The array of nanofibers can be configured to filter a predetermined contaminant from a fluid stream passing through the mats. Filter ribbons are formable by applying a moldable polymer to a first angular location of a rotating cylindrical roll having an array of nanoholes formed in a circumferential surface thereof so that the polymer covers the surface of the roll and infiltrates the nanoholes; cooling the polymer while rotating the polymer-covered roll to a second angular position; and removing the cooled polymer from the roll as an elongate film having an array of nanofibers formed on a surface thereof by the polymer that infiltrated the nanoholes.

In a method for producing a filter medium, at least one substrate layer of a nonwoven comprising cellulose fibers and/or synthetic polymer fibers is provided and a fiber layer of polymer fibers is deposited on the at least one substrate layer. Prior to depositing the fiber layer, a solvent is applied to the at least one substrate layer, wherein a material of the substrate layer and/or a material of the fiber layer is soluble in the solvent. A filter medium produced by the method has material-fused connections at crossing points of the polymer fibers and/or cellulose fibers of the substrate layer with the polymer fibers of the fiber layer.

A sintered metal object comprises metal fibers in a nonwoven web arrangement. The metal fibers comprise stainless steel fibers having a duplex microstructure. The duplex microstructure is a mixed microstructure of austenite and ferrite. The stainless steel fibers are bonded at at least part of their contacting points by means of sinter bonds.

A filter medium is provided with a layer (A) provided with non-impregnated active carbon, a layer (B) with a solid carrier material that is impregnated with a permanganate salt, and a layer (C) with alkaline impregnated active carbon. The layer (B) and the layer (C) are arranged such that a gas flowing through the filter medium flows through the layer (B) before flowing through the layer (C). The layer (A) is arranged such that the gas flowing through the filter medium flows through the layer (A) before flowing through the layer (B) or the gas flowing through the filter medium flows through the layer (A) after flowing through the layer (C).

A poly(phenylene sulfide) fiber changes little in fiber structure and has excellent long-term heat resistance. Namely, the poly(phenylene sulfide) fiber has a degree of crystallization of 45.0% or higher, a content of movable amorphous components of 15.0% or less, and a weight-average molecular weight of 300,000 or less.