Abstract: Provided is a porous membrane that can be manufactured in uncomplicated steps, has high hydrophilicity and water permeability, and exhibits excellent anti-fouling properties when used in a membrane bioreactor method (MBR method). The porous membrane of the present invention is a porous membrane containing polymer (A) and polymer (B), wherein the polymer (A) is a membrane-forming polymer, the polymer (B) is a polymer having a unit (b1) represented by formula (1) and a unit (b2) based on hydroxyl group-containing (meth)acrylate, and the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the porous membrane.

Abstract: A porous membrane comprising a membrane-forming polymer (A) and a polymer (B) containing a methyl methacrylate unit and a hydroxyl group-containing (meth)acrylate (b1) unit. A flux of pure water to permeate the porous membrane is preferably 10 (m3/m2/MPa/h) or more and less than 200 (m3/m2/MPa/h). The contact angle of the bulk of the membrane-forming polymer (A) is preferably 60° or more. The membrane-forming polymer (A) is preferably a fluorine-containing polymer. The polymer (B) is preferably a random copolymer.

Abstract: Provided is a porous membrane that can be manufactured in uncomplicated steps, has high hydrophilicity and water permeability, and exhibits excellent anti-fouling properties when used in a membrane bioreactor method (MBR method). The porous membrane of the present invention is a porous membrane containing polymer (A) and polymer (B), wherein the polymer (A) is a membrane-forming polymer, the polymer (B) is a polymer having a unit (b1) represented by formula (1) and a unit (b2) based on hydroxyl group-containing (meth)acrylate, and the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the porous membrane.

Abstract: A porous membrane comprising a membrane-forming polymer (A) and a polymer (B) containing a methyl methacrylate unit and a hydroxyl group-containing (meth)acrylate (b1) unit. A flux of pure water to permeate the porous membrane is preferably 10 (m3/m2/MPa/h) or more and less than 200 (m3/m2/MPa/h). The contact angle of the bulk of the membrane-forming polymer (A) is preferably 60° or more. The membrane-forming polymer (A) is preferably a fluorine-containing polymer. The polymer (B) is preferably a random copolymer.

Abstract: A hollow porous membrane of the present invention comprises a plurality of porous membrane layers, at least two layers of which are formed using a thermoplastic resin (a) having a mass average molecular weight of 500,000 or more, and the hollow porous membrane having a bursting pressure of 200 kPa or more when an internal pressure is applied and exhibiting virus removal performance of LRV 4 or more in the case of using MS2 phage as a test bacterium.

Abstract: A hollow fiber membrane-spinning nozzle that spins a hollow fiber membrane having a porous membrane layer and a support is provided in which the nozzle includes a resin flow channel through which a membrane-forming resin solution forming the porous membrane layer flows, the resin flow channel includes a liquid storage section that stores the membrane-forming resin solution and a shaping section that shapes the membrane-forming resin solution in a cylindrical shape and satisfies at least one of conditions (a) to (c): (a) the resin flow channel is disposed to cause the membrane-forming resin solution to branch and merge; (b) a delay means for delaying the flow of the membrane-forming resin solution is disposed in the resin flow channel; and (c) the liquid storage section or the shaping section includes branching and merging means for the membrane-forming resin solution therein.

Abstract: A hollow porous membrane including a porous membrane layer having a hole on an outer surface, wherein a membrane thickness of the porous membrane layer is 70 ?m or more, and the porous membrane layer has a region A, the correlation between a depth X (?m) and an average pore size Y (?m) of holes on a cutting plane at the depth X (?m) satisfies a regression line Y=aX+b in the case of cutting an outer surface of the porous membrane layer by the depth X (?m) in the region A, a slope a of the regression line is 0<a?0.08 and a coefficient of determination R2 of the regression line is 0.90 or more, and a, b, and R2 are determined by the following Equations (2?), Equation (3?), and Equation (4?), respectively.

Abstract: Disclosed is a process for production of a porous membrane that includes the steps of layering a film-forming dope that contains a polymer (A) that forms a membrane base, a polyvinylpyrrolidone (B) and a solvent (C) into a single layer or two or more layers; immersing the film-forming dope in a solidifying fluid that is a non-solvent with respect to the polymer (A) and is a good solvent with respect to the polyvinylpyrrolidone (B); and removing the polyvinylpyrrolidone (B), wherein the polyvinylpyrrolidone (B) has a K value of 50 to 80, a mass ratio r of the polyvinylpyrrolidone (B) to the polymer (A) is 0.5 or more and less than 1, and the viscosity of the film-forming dope at a membrane production temperature is 100 to 500 Pa·s.

Abstract: The present invention relates to a hollow porous membrane comprising a porous membrane layer and a support, wherein the porous membrane layer is composed of a thermoplastic resin and the support is a support obtained by processing a yarn having a stretch elongation rate of 1.0% or less into a tubular shape. According to the present invention, it is possible to provide a hollow porous membrane capable of maintaining sufficient physical strength and favorable water permeability despite its small outer diameter value.

Abstract: A hollow porous membrane of the present invention comprises a plurality of porous membrane layers, at least two layers of which are formed using a thermoplastic resin (a) having a mass average molecular weight of 500,000 or more, and the hollow porous membrane having a bursting pressure of 200 kPa or more when an internal pressure is applied and exhibiting virus removal performance of LRV 4 or more in the case of using MS2 phage as a test bacterium.

Abstract: A hollow porous membrane with a reduced cost and excellent separation characteristic, water permeability, and mechanical strength and a process of producing the hollow porous membrane with an excellent adhesive property between a support and a porous membrane layer at a low cost are provided. The hollow porous membrane includes a porous membrane layer in which dense layers are disposed in the vicinities of an outer surface and an inner surface. In the process of producing the hollow porous membrane, membrane-forming dopes of a first membrane-forming dope and a second membrane-forming dope, which contain the material of the porous membrane layer and a solvent, are successively applied and stacked onto the outer circumferential surface of a hollow support and the applied membrane-forming dopes are simultaneously coagulated.

Abstract: A hollow fiber membrane-spinning nozzle that spins a hollow fiber membrane having a porous membrane layer and a support is provided in which the nozzle includes a resin flow channel through which a membrane-forming resin solution forming the porous membrane layer flows, the resin flow channel includes a liquid storage section that stores the membrane-forming resin solution and a shaping section that shapes the membrane-forming resin solution in a cylindrical shape and satisfies at least one of conditions (a) to (c): (a) the resin flow channel is disposed to cause the membrane-forming resin solution to branch and merge; (b) a delay means for delaying the flow of the membrane-forming resin solution is disposed in the resin flow channel; and (c) the liquid storage section or the shaping section includes branching and merging means for the membrane-forming resin solution therein.

Abstract: Disclosed is a process for production of a porous membrane that includes the steps of layering a film-forming dope that contains a polymer (A) that forms a membrane base, a polyvinylpyrrolidone (B) and a solvent (C) into a single layer or two or more layers; immersing the film-forming dope in a solidifying fluid that is a non-solvent with respect to the polymer (A) and is a good solvent with respect to the polyvinylpyrrolidone (B); and removing the polyvinylpyrrolidone (B), wherein the polyvinylpyrrolidone (B) has a K value of 50 to 80, a mass ratio r of the polyvinylpyrrolidone (B) to the polymer (A) is 0.5 or more and less than 1, and the viscosity of the film-forming dope at a membrane production temperature is 100 to 500 Pa·s.

Abstract: A hollow porous membrane with a reduced cost and excellent separation characteristic, water permeability, and mechanical strength and a process of producing the hollow porous membrane with an excellent adhesive property between a support and a porous membrane layer at a low cost are provided. The hollow porous membrane includes a porous membrane layer in which dense layers are disposed in the vicinities of an outer surface and an inner surface. In the process of producing the hollow porous membrane, membrane-forming dopes of a first membrane-forming dope and a second membrane-forming dope, which contain the material of the porous membrane layer and a solvent, are successively applied and stacked onto the outer circumferential surface of a hollow support and the applied membrane-forming dopes are simultaneously coagulated.

Abstract: There are disclosed a polymer packing material suitable for liquid chromatography and a producing method thereof. The polymer packing material having a polymer particle based on a styrene skeleton with monodispersed particle distribution can be obtained by hydrophilic treatment of an inner surface of a micropore existing in a fine pore of the polymer packing material, or subsequent introduction of a hydrophobic group into the inner hydrophilic surface by chemical modification. A method of producing the polymer packing material suitable for liquid chromatography includes the step of polymerizing glycerol dimethacrylate as a crosslinking agent and 2-ethylhexl methacrylate as a monomer according to a two-step swelling polymerization process. Alternatively, the producing method includes the step of crosslinking and polymerizing only glycerol dimethacrylate to form a polymer, and introducing the hydrophobic group into the polymer by chemical modification.