Provided is a ventilation member for a vehicle lamp. The ventilation member includes a nanofiber membrane, a composite adhesive layer stacked on one surface of the nanofiber membrane, and a ventilation structure provided in a central portion of the composite adhesive layer and in contact with the nanofiber membrane. The composite adhesive layer includes an acrylic adhesive layer in contact with the nanofiber membrane and a silicone-based adhesive layer provided on one surface of the acrylic adhesive layer. The acrylic adhesive layer is in contact with the nanofiber membrane, the acrylic adhesive layer is infiltrated into the nanofiber membrane to a depth of 30 μm or more. The ventilation member for a vehicle lamp has a water pressure resistance of 1.0 bar or more.

A laminated acoustic absorption member that includes at least a first fiber layer and a second fiber layer, as well as at least one substrate layer present between the first fiber layer and the second fiber layer, wherein: the first fiber layer has an average flow pore diameter of 0.5-10 μm and a basis weight of 0.1-200 g/m.sup.2; the second fiber layer has an average flow pore diameter of 0.5-10 μm, the average flow pore diameter of the second fiber layer being equal to or less than that of the first fiber layer, and also has a basis weight of 0.1-200 g/m.sup.2; the substrate layer has an air permeability of 40 cc/cm.sup.2.Math.s or greater as measured by the Frazier method, and a basis weight of 1-700 g/m.sup.2; and the first fiber layer and the second fiber layer are disposed on a sound-incidence side and a sound-transmission side, respectively.

The present invention addresses the problem of providing a sound absorption member which exhibits excellent sound absorption performance from a low frequency range to a high frequency range. A laminated sound absorption member which comprises at least two fiber layers and at least one base material layer that is arranged between a fiber layer and another fiber layer. The fiber layers have a void fraction of from 85% to 94% (inclusive) and a density of from 0.06 g/cm.sup.3 to 0.5 g/cm.sup.3 (inclusive). The base material layer has a void fraction of 95% or more but less than 100% and a density of from 0.008 g/cm.sup.3 to 0.05 g/cm.sup.3 (inclusive). The base material layer is composed of at least one fabric selected from the group consisting of nonwoven fabrics and woven fabrics.

The present invention addresses the problem of providing a sound absorption member which exhibits excellent sound absorption performance from a low frequency range to a high frequency range. A laminated sound absorption member which comprises at least two fiber layers and at least one base material layer that is arranged between a fiber layer and another fiber layer. The fiber layers have a void fraction of from 85% to 94% (inclusive) and a density of from 0.06 g/cm.sup.3 to 0.5 g/cm.sup.3 (inclusive). The base material layer has a void fraction of 95% or more but less than 100% and a density of from 0.008 g/cm.sup.3 to 0.05 g/cm.sup.3 (inclusive). The base material layer is composed of at least one fabric selected from the group consisting of nonwoven fabrics and woven fabrics.

A filter medium is provided. A filter medium according to an embodiment of the present invention comprises: a fiber web layer of a three-dimensional network structure including nanofiber; and a hydrophilic coating layer which covers at least a part of the outer surface of the nanofiber. According to this, a flow rate can be remarkably increased due to the improved hydrophilicity of the filter medium. Also, as the improved hydrophilicity is maintained for a long period of time, the lifespan can be remarkably prolonged. Furthermore, since the modification of a porous structure of the filter medium is minimized during the process of hydrophilization so that the initially designed physical properties of the filter medium can be exhibited in its entirety, the filter medium having chemical resistance, excellent water permeability and durability can be variously applied in the water treatment field.

A filter medium is provided. A filter medium according to an embodiment of the present invention comprises: a fiber web layer of a three-dimensional network structure including nanofiber; and a hydrophilic coating layer which covers at least a part of the outer surface of the nanofiber. According to this, a flow rate can be remarkably increased due to the improved hydrophilicity of the filter medium. Also, as the improved hydrophilicity is maintained for a long period of time, the lifespan can be remarkably prolonged. Furthermore, since the modification of a porous structure of the filter medium is minimized during the process of hydrophilization so that the initially designed physical properties of the filter medium can be exhibited in its entirety, the filter medium having chemical resistance, excellent water permeability and durability can be variously applied in the water treatment field.

The present invention aims to provide a sheet of microfiber assembly having a high filtering performance suitable as an oil-mist filter. A sheet of microfiber assembly 2 comprises microfibers 1 each having a fiber diameter of 3,000 nm or less and is formed of a mixture of water-insoluble but alcohol-soluble acetalized polyvinyl alcohol resin and water-insoluble but alcohol-soluble fluorine resin.

The present invention aims to provide a sheet of microfiber assembly having a high filtering performance suitable as an oil-mist filter. A sheet of microfiber assembly 2 comprises microfibers 1 each having a fiber diameter of 3,000 nm or less and is formed of a mixture of water-insoluble but alcohol-soluble acetalized polyvinyl alcohol resin and water-insoluble but alcohol-soluble fluorine resin.

A nanofiber for a filter medium is provided that includes fiber-forming ingredients including polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) and an emulsifying agent for improving the miscibility of the fiber-forming ingredients. The nanofiber has excellent mechanical strength and chemical resistance and, at the same time, significantly increased hydrophilicity without a separate surface modification/treatment to/on the nanofiber. A filter medium comprising said nanofiber can exhibit improved flux and filtration efficiency and excellent physical properties in a water treatment process in which a pressure equal to or more than a predetermined level is applied and which requires the filter medium to have high mechanical strength and in a water treatment process which requires chemical resistance as the liquid being filtered is strongly acidic or alkaline. Further, since the nanofiber has significantly superior spinnability, the mass productivity of the filter medium is significantly improved, and the unit costs of production can be reduced.

A nanofiber for a filter medium is provided that includes fiber-forming ingredients including polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) and an emulsifying agent for improving the miscibility of the fiber-forming ingredients. The nanofiber has excellent mechanical strength and chemical resistance and, at the same time, significantly increased hydrophilicity without a separate surface modification/treatment to/on the nanofiber. A filter medium comprising said nanofiber can exhibit improved flux and filtration efficiency and excellent physical properties in a water treatment process in which a pressure equal to or more than a predetermined level is applied and which requires the filter medium to have high mechanical strength and in a water treatment process which requires chemical resistance as the liquid being filtered is strongly acidic or alkaline. Further, since the nanofiber has significantly superior spinnability, the mass productivity of the filter medium is significantly improved, and the unit costs of production can be reduced.