Disclosed is an air filter using high density filter paper. The filter paper may include a thermally bonded non-woven fabric filter paper 10 having air permeability to filter foreign materials of passed polluted air and change the polluted air to fresh air. The non-woven fabric filter paper includes wrinkled portions 10-1 and 10-N that are folded at a predetermined interval. A thickness of the wrinkle portions 10-1 and 10-N are provided with dense layers 15 and 17 comprising a first polyethylene terephthalate (PET) fiber 20-2 that can shrink by heat and a second polyethylene terephthalate (PET) fiber 20-1 that deforms upon by heat treatment.

A face mask containing a network of conductive activated carbon meso-fibers crosslinked with a crosslinking agent bonded to a insulative polymeric micro-fiber based purification element. The purification element is captured between two ridged porous elements and contacted to the face by a biocompatible flexible polymeric seal. Optionally the front cover attaches to a main frame of the mask through a system of sliding locks that are coupled with bayonet latch mechanisms. The face mask attaches to the head of a wearer through a harness that couples with the sliding locks or alternatively with a biocompatible adhesive.

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.

Spunbonded electret webs comprising polylactic acid fibers, in which at least some of the polylactic acid fibers are meltspun, drawn, charged fibers that include charging additive; and, methods of making such fibers and webs.

Filter media including a filtration layer comprising fibers (e.g., synthetic fibers) comprising a flame retardant and related components, systems, and methods associated herewith are provided. In some embodiments, a filtration layer may include a nonwoven web (e.g., wet-laid nonwoven web) comprising fibers including a certain flame retardant that has a relatively low concentration of or is substantially free of certain undesirable and/or toxic components (e.g., halogens). In certain embodiments, the nonwoven web may also comprise a blend of fibers. For instance, in some embodiments, the nonwoven web may also comprise a blend of coarse and fine diameter synthetic fibers that impart beneficial performance properties to the filtration layer. In some embodiments, the filtration layer may be designed to have a desirable flame retardancy (e.g., F1 rating, K1 rating) and performance properties without compromising certain mechanical properties (e.g., pleatability of the media) and/or environmental attributes (e.g., relatively low toxicity). Filter media described herein may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

Filter media comprising a filtration layer comprising synthetic fibers (e.g., pleatable backer layer) and related components, systems, and methods associated herewith are provided. In some embodiments, the filtration layer comprising synthetic fibers may be a non-woven web comprising a blend of coarse and fine diameter fibers. The filtration layer comprising synthetic fibers may be designed to have desirable performance properties without compromising certain mechanical properties, such as the pleatability of the media. In some embodiments, a filter media, described herein, may comprise the filtration layer comprising synthetic fibers and an efficiency layer. Filter media, as described herein, may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

The present invention provides a novel nonwoven felt fabric, which is made of at least one low-melting-point short fiber and at least one high-melting-point short fiber of same type or different types, wherein the fabric is stiff enough to be self-sustaining and have the ability of shape maintenance. The felt fabric exhibits excellent pleatability, moldability and compressive strength. The invention also provides a method for producing the felt fabric, and a filter comprising the felt fabric used as the material of a filter medium of the filter, wherein the filter medium requires no support structure to stand alone and persistently retains its shape.

Thermoplastic bicomponent binder fiber can be combined with other media, fibers and other filtration components to form a thermally bonded filtration media. The filtration media can be used in filter units, such as breather caps. Such filter units can be placed in the stream of a mobile fluid and can remove a particulate and/or fluid mist load from the mobile stream. The unique combination of media fiber, bicomponent binder fiber and other filtration additives and components provide a filtration media having unique properties in filtration applications.

The invention concerns spunbond nonwoven fabrics comprising a plurality of bicomponent filaments, the bicomponent filaments having a segmented pie cross-sectional configuration including a polycarbonate component and a polypropylene component, wherein a ratio of the polypropylene component to the polycarbonate component is between about 5:95 and about 95:5.

An air filter for automobiles includes, a main filter and a prefilter, wherein the prefilter comprises a nonwoven synthetic fiber having an average density of 0.01 to 0.5 g/cm.sup.3 and a moisture absorbent is adsorbed to the prefilter.