A method for preparing a composite filter medium (1), comprising a step of forming a first filter medium (8) through deposition of nanofibers (4) on a base fabric (2) through an electrospinning process and a step of covering said filter medium (1) by plasma deposition of a coating (7) on said first filter medium (8) in a vacuum chamber (9). According to the invention, after the electrospinning process and before the plasma deposition of the coating (7), a degassing step of the base fabric (2) and of the nanofibers (4) forming the aforementioned first filter medium (8) is provided inside the same chamber (9). With respect to the known filter media, that of the invention offers the advantage of maintaining the desired level of water and oil repellency, due to the formation of a completely polymerized coating strongly adhering to the surface of the base fabric and of the nanofibers.

The present invention relates to a sheet filter material, in particular having an aerosol filter function and/or a particle filter function, preferably having a protective function against chemical, biological and/or chemical harmful and toxic substances, and to a method for the production thereof. The sheet filter material is particularly suitable for producing protective equipment, protective objects, sports and leisure clothing and filters and filter materials of all types.

A filter medium is provided. The filter medium according to an embodiment of the present invention comprises: a first support body having a plurality of pores; a nanofiber web comprising nanofibers disposed on upper and lower sides of the first support body and forming a three dimensional network structure; and a second support body having a plurality of pores interposed between the first support body and the nanofiber web, wherein the nanofiber web is realized as a filter medium that satisfies: (1) an elongation of 25% or more, (2) an air permeability of 0.1 to 2.00 cfm, and 3) porosity of 60%˜85%. Accordingly, since the filter medium has a fixed level of mechanical properties of the nanofiber web, the shape, structure deformation, and damage of the filter medium are minimized and a flow path is smoothly secured during a water treatment operation so that the filter medium can have a high flow rate. In addition, since the filter medium of the present invention has a prolonged use life due to excellent durability of the filter medium even at high pressure applied during backwashing, and has excellent filtration efficiency and water permeability, the filter medium can be applied in various ways in various water treatment fields.

A filter bag is disclosed that comprises a porous membrane having a strength in the transverse direction to improve durability. There is a filter assembly for filtering particulates from a gas stream comprising a support substructure and a filter bag at least partially surrounding the support substructure. The filter bag comprises a porous membrane having a upstream surface exposed to the gas stream. The porous membrane is lightweight and has a structure to collect the particulates on the upstream surface. In particular, the porous membrane has a bubble point of 0.06 MPa or more and has a strength in a transverse direction that is 100 N/m or more. Other filter bags disclosed comprise a laminate comprising a porous membrane having a bubble point of 0.06 MPa or more and a second layer that acts as a sacrificial material.

A composite media alternative to high pressure drop glass microfiber HEPA media for use in applications where HEPA efficiency with an oily aerosol challenge with low resistance are required. The composite media contains two light filtration layers, one or both of which is charged, and the efficiency of the material can be greatly increased over a single layer containing the same weight of material. The composite media contains a backer layer to provide mechanical support to the filtration layers.

Disclosed here is a composite filter media having at least one nanofiber layer bonded to a substrate layer, the at least one nanofiber layer optionally having a plurality of nanofibers having a geometric mean diameter of less than or equal to 0.5 μm, the at least one nanofiber layer having a thickness of about 1-100 μm.

A porous electrospun polymeric nanofiber liquid filtration medium, such as an electrospun mats, used for the removal of viral particles (e.g., parvovirus) and other particles in the 18 nm to 30 nm size range from fluid streams, having a mean flow bubble point measured with perfluorohexane above 100 psi. The electrospun medium includes nanofibers having an average fiber diameter of about 6 nm to about 13 nm, and the nanofiber liquid filtration medium has a mean pore size ranging from about 0.01 μm to about 0.03 μm, a porosity ranging from about 80% to about 95%, a thickness ranging from about 1 μm to about 100 μm, and a liquid permeability greater than about 10 LMH/psi. The high porosity of the electrospun mats enable much higher water fluxes, thus reducing the time required to complete virus filtration steps on a fluid stream.

Filtration media packs, filter elements, and media are disclosed, including media packs having a plurality of layers of single facer media wherein the layers of single facer media include a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet, with the fluted sheet and facing sheet formed of multi-layer media can include a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer.

Provided is a porous polytetrafluoroethylene membrane in which an absolute value of a difference in lightness between one principal surface and the other principal surface is 1.0 or more, where the lightness is lightness L* of CIE 1976 (L*, a*, b*) color space specified in JIS Z8781-4: 2013. The porous polytetrafluoroethylene membrane may be colored black or gray. The porous polytetrafluoroethylene membrane provided can have properties with a reduced coloring-induced deterioration.

It is an object of the present invention to provide a filter having excellent filtration rate and excellent permeability and a method for producing the same. To achieve the above object, the present invention provides a filter comprising a porous metal support having the first pore size; and a metal coating layer formed on the support and having the second pore size smaller than the first pore size, wherein the coating layer has a three-dimensional pore structure by bonding flake-shaped metal powders. The present invention also provides a method for producing the filter. According to the present invention, as the flake-shaped second powders form a coating layer, the porosity increases and the permeability increases, and as the flow channel becomes more complicated, the filtration rate also increases.