Abstract: The present invention provides an air-permeable filter capable of maintaining excellent air permeation performance without being clogged even in an environment involving exposure to an oil, oil mist, or ink. The present invention relates to an air-permeable filter including a porous membrane having a surface coated with an oil-repellent agent, the filter being characterized in that a sliding angle of 20 ?l of hexadecane or pentadecane on the surface of the filter is 60° or less.

Abstract: The present invention provides an air-permeable filter capable of maintaining excellent air permeation performance without being clogged even in an environment involving exposure to an oil, oil mist, or ink. The present invention relates to an air-permeable filter including a porous membrane having a surface coated with an oil-repellent agent, the filter being characterized in that a sliding angle of 20 ?l of hexadecane or pentadecane on the surface of the filter is 60° or less.

Abstract: A gas-permeable filter provided with oil repellency is provided. The gas-permeable filter includes a porous membrane having a surface coated with an oil-repellent agent. The oil-repellent agent includes a linear fluorine-containing hydrocarbon group represented by —R1C5F10CH2C4F9 or —R2C6F13, and the porous membrane is a stretched polytetrafluoroethylene (PTFE) porous membrane. Here, R1 and R2 are each independently an alkylene group having 1 to 12 carbon atoms or a phenylene group. The gas-permeable filter is provided with oil repellency without significant reduction in gas permeability.

Abstract: Disclosed is an air-permeable filter with an adhesive layer. This air-permeable filter is imparted with oil repellency and includes: a porous membrane having a surface coated with an oil-repellent agent; and an adhesive layer disposed on the surface. The oil-repellent agent contains a linear fluorine-containing hydrocarbon group represented by (1) —R1C5F10CH2C4F9 or (2) —R2C6F13, where R1 and R2 are each independently an alkylene group having 1 to 12 carbon atoms or a phenylene group. This air-permeable filter is imparted with oil repellency without significantly reducing its adhesive strength to the adhesive layer.

Abstract: A gas-permeable filter of the present invention has a surface coated with an oil-repellent agent. The oil-repellent agent contains a copolymer of a linear fluorine-containing hydrocarbon group-containing monomer and a crosslinkable monomer. The crosslinkable monomer contains at least one selected from an alkoxy group-containing monomer, a hydroxy group-containing monomer, and a carboxyl group-containing monomer.

Abstract: Disclosed is an air-permeable filter with an adhesive layer. This air-permeable filter is imparted with oil repellency and includes: a porous membrane having a surface coated with an oil-repellent agent; and an adhesive layer disposed on the surface. The oil-repellent agent contains a linear fluorine-containing hydrocarbon group represented by (1) —R1C5F10CH2C4F9 or (2) —R2C6F13, where R1 and R2 are each independently an alkylene group having 1 to 12 carbon atoms or a phenylene group. This air-permeable filter is imparted with oil repellency without significantly reducing its adhesive strength to the adhesive layer.

Abstract: A gas-permeable filter provided with oil repellency is provided. The gas-permeable filter includes a porous membrane having a surface coated with an oil-repellent agent. The oil-repellent agent includes a linear fluorine-containing hydrocarbon group represented by —R1C5F10CH2C4F9 or —R2C6F13, and the porous membrane is a stretched polytetrafluoroethylene (PTFE) porous membrane. Here, R1 and R2 are each independently an alkylene group having 1 to 12 carbon atoms or a phenylene group. The gas-permeable filter is provided with oil repellency without significant reduction in gas permeability.