A yarn containing a potential-generating filament. The yarn is constructed such that a positive or negative surface electrical potential is generated by applying an external force to the yarn in an axial direction of the yarn, and constructed such that a controlled surface electrical potential is generated by a maintenance or release of the external force.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The additives are substituted benzothiazole compounds or substituted benzoxazole compounds. The substituent groups may be hydroxyl, mercapto, or aromatic groups. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

Process for the removal of particulate matter from an aqueous stream containing a concentrated acid, preferably concentrated sulfuric acid, the process including mechanical filtration by passing the aqueous stream through a filter unit, the filter unit including a metallic, ceramic or polymeric filter, or a filter including a filter aid on a septum. The aqueous stream is the exit stream of a sulfuric acid condenser, optionally the exit stream of a sulfuric acid concentrator arranged downstream the sulfuric acid condenser.

The invention relates to a filter element having inherent stability and being porous to permit flow therethrough, comprising a filter body which forms a porous sintered structure and is constructed with filter body particles which are at least in part polysulfide particles. In addition, the invention relates to a method of manufacturing such a filter element.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The charge-enhancing additive is a dual-function charge-enhancing additive that enhances the charge of the electret and also has anti-microbial properties. The additives are substituted-benzimidazole or substituted-benzothiazole compounds. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

This disclosure describes a filter medium that minimizes the adverse effects of variations in flow rate on filter medium efficiency without a corresponding increase in pressure drop. The filter medium includes a support layer, a continuous fine fiber layer, and an efficiency layer. The continuous fine fiber layer includes a continuous fine fiber that has a diameter of up to 10 micrometers and is located downstream of the efficiency layer.

A filter assembly including a filtration medium comprising a nanofiber, having a three-dimensional network structure, and having a fiber web layer comprising a hydrophilic coating layer that covers at least a part of the outer surface of the nanofiber; and a first support body that supports the filtration medium, which is provided on both surfaces thereof, and has a channel formed therein. Accordingly, the filtration medium has excellent chemical resistance and improved hydrophilicity such that the flow rate can increase substantially. In addition, the improved hydrophilicity is maintained for a long period of time such that the utilization period can be extended substantially. Furthermore, any change in the pore structure of the filtration medium during the hydrophilicity endowing process is minimized such that the initially designed physical characteristics of the filtration medium can be fully exhibited.

A filter assembly including a filtration medium comprising a nanofiber, having a three-dimensional network structure, and having a fiber web layer comprising a hydrophilic coating layer that covers at least a part of the outer surface of the nanofiber; and a first support body that supports the filtration medium, which is provided on both surfaces thereof, and has a channel formed therein. Accordingly, the filtration medium has excellent chemical resistance and improved hydrophilicity such that the flow rate can increase substantially. In addition, the improved hydrophilicity is maintained for a long period of time such that the utilization period can be extended substantially. Furthermore, any change in the pore structure of the filtration medium during the hydrophilicity endowing process is minimized such that the initially designed physical characteristics of the filtration medium can be fully exhibited.

A thermoplastic core-sheath fiber comprises: a polymer fiber core having a coextensive sheath layer disposed thereon, and an electrostatic charge enhancing additive. The sheath layer may comprise poly(4-methyl-1-pentene) and the fiber core and the sheath layer have different compositions. At least one of the fiber core or the sheath layer comprises an electret charge. A nonwoven fibrous web comprising the core-sheath fibers and a respirator including the nonwoven fibrous web are also disclosed.

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.