Abstract: Disclosed is an asymmetric gas separation membrane made of a soluble aromatic polyimide having a specific repeating unit, the soluble aromatic polyimide including: as a tetracarboxylic acid component, a biphenyl structure and a phenyl structure; as a diamine component, a 3,3?-diaminodiphenyl sulphone and a diaminodibenzothiophene, a diaminodibenzothiophene=5,5-dioxide, a diaminothioxanthene-10,10-dione, or a diaminothioxanthene-9,10,10-trione. Disclosed is a method for selectively separating and recovering a specific gas species from a mixed gas composed of a plurality of gas species using the asymmetric gas separation membrane, a method for selectively separating and recovering a nitrogen-rich gas from air using the asymmetric gas separation membrane, and a method for selectively separating carbon dioxide gas from a mixed gas containing carbon dioxide and methane and recovering methane-rich gas using the asymmetric gas separation membrane.

Abstract: An asymmetric gas separation membrane made of an aromatic polyimide mainly containing repeating units having an ether bond which is heated at a temperature near a softening point (Ts) of the aromatic polyimide, and a method for separating methanol from a methanol-containing mixed organic vapor by allowing methanol to selectively permeate the asymmetric gas separation membrane using the membrane.

Abstract: An asymmetric gas separation membrane made of an aromatic polyimide mainly containing repeating units having an ether bond which is heated at a temperature near a softening point (Ts) of the aromatic polyimide, and a method for separating methanol from a methanol-containing mixed organic vapor by allowing methanol to selectively permeate the asymmetric gas separation membrane using the membrane.

Abstract: An asymmetric hollow fiber gas separation membrane obtained by subjecting an asymmetric hollow fiber polyimide membrane to a heat treatment having a maximum temperature of from 350 to 450° C., wherein the asymmetric hollow fiber polyimide membrane is formed with a polyimide essentially having a repeating unit represented by a general formula (1); is excellent in a solvent resistance and a thermal stability, and as well has such a mechanical strength that a tensile elongation at break is not less than 10% as a hollow fiber membrane.

Abstract: There is disclosed an asymmetric gas separation membrane exhibiting both improved gas separation performance and improved mechanical properties, which is made of a soluble aromatic polyimide comprised of a repeating unit represented by general formula (1): wherein B in general formula (1) B comprises 10 to 70 mol % of tetravalent unit B1 represented by general formula (B1) and 90 to 30 mol % of tetravalent unit B2 represented by general formula (B2), and A in general formula (1) comprises 10 to 50 mol % of bivalent unit A1 represented by general formula (A1a) or the like and 90 to 30 mol % of bivalent unit A2 represented by general formula (A2a) or the like.

Abstract: Disclosed are a gas separation membrane and a gas separation method in which at least one species of organic vapor is separated and recovered from an organic vapor mixture using the gas separation membrane. The gas separation membrane is made of an aromatic polyimide composed of a tetracarboxylic acid component consisting of an aromatic ring-containing tetracarboxylic acid and a diamine component comprising 10 to 90 mol % of a combination of (B1) 3,4?-diaminodiphenyl ether and (B2) 4,4?-diaminodiphenyl ether at a B1 to B2 molar ratio, B1/B2, ranging from 10/1 to 1/10, and 10 to 90 mol % of other aromatic diamine.

Abstract: A polyimide film made of a multicomponent polyimide comprising two or more different polyimide components including (A) a polyimide component A being raw materials of a polyimide A and/or a polyimidation product of the raw materials and (B) a polyimide component B being raw materials of a polyimide B and/or a polyimidation product of the raw materials. The polyimide components A and B are different, for example, such that the absolute difference between solubility parameter SPA of the polyimide A and solubility parameter SPB of the polyimide B, |SPB-SPA|, is 0.5 MPa1/2 or more. The polyimide film has markedly modified surface properties as compared with a polyimide film in which all the same raw materials as used in the film of the invention are randomly bonded to one another.

Abstract: There is disclosed an asymmetric gas separation membrane exhibiting both improved gas separation performance and improved mechanical properties, which is made of a soluble aromatic polyimide comprised of a repeating unit represented by general formula (1): wherein B in general formula (1) B comprises 10 to 70 mol % of tetravalent unit B1 represented by general formula (B1) and 90 to 30 mol % of tetravalent unit B2 represented by general formula (B2), and A in general formula (1) comprises 10 to 50 mol % of bivalent unit A1 represented by general formula (A1a) or the like and 90 to 30 mol % of bivalent unit A2 represented by general formula (A2a) or the like.

Abstract: An asymmetric hollow fiber gas separation membrane obtained by subjecting an asymmetric hollow fiber polyimide membrane to a heat treatment having a maximum temperature of from 350 to 450° C., wherein the asymmetric hollow fiber polyimide membrane is formed with a polyimide essentially having a repeating unit represented by a general formula (1); is excellent in a solvent resistance and a thermal stability, and as well has such a mechanical strength that a tensile elongation at break is not less than 10% as a hollow fiber membrane.

Abstract: Disclosed are a gas separation membrane and a gas separation method in which at least one species of organic vapor is separated and recovered from an organic vapor mixture using the gas separation membrane. The gas separation membrane is made of an aromatic polyimide composed of a tetracarboxylic acid component consisting of an aromatic ring-containing tetracarboxylic acid and a diamine component comprising 10 to 90 mol % of a combination of (B1) 3,4?-diaminodiphenyl ether and (B2) 4,4?-diaminodiphenyl ether at a B1 to B2 molar ratio, B1/B2, ranging from 10/1 to 1/10, and 10 to 90 mol % of other aromatic diamine.

Abstract: A process of producing an asymmetric membrane of multicomponent polyimide. The process includes the steps of (1) preparing a multicomponent polyimide blend solution by mixing a polyimide component A having a number-averaged polymerization index NA and a polyimide component B having a number-averaged polymerization index NB, wherein NA and NB satisfies equation 1: 2.35×NA?2.09<NB<450×NA?1.12??1 (2) subjecting the multicomponent polyimide blend solution to further polymerization and imidation reaction, and (3) causing a phase inversion in the resulting multicomponent polyimide blend solution to form an asymmetric membrane. The polyimide component A is raw materials of polyimide A containing a fluorine atom in the chemical structure thereof and/or a polymerization and imidation reaction product of the raw materials. The polyimide component B is raw materials of polyimide B and/or a polymerization and imidation reaction product of the raw materials.

Abstract: The present invention relates to an asymmetric hollow-fiber gas separation membrane made of a polyimide having a specific repeating unit, an improved tensile elongation at break of 15% or more as a hollow-fiber membrane itself, an oxygen gas permeation rate (P?O2) of 4.0×10?5 cm3(STP)/cm2·sec·cmHg or more and a gas ratio of permeation rate of oxygen to nitrogen (P?O2/P?N2) of 4 or more that are measured at 50° C., a gas separation method and a gas separation membrane module using the asymmetric hollow-fiber gas separation membrane. In addition, the present invention relates to an asymmetric hollow-fiber gas separation membrane obtained by heat-treating the asymmetric hollow-fiber gas separation membrane at a maximum temperature of from 350 to 450° C. The asymmetric hollow-fiber gas separation membrane has sufficient mechanical strength even after the heat-treatment at a maximum temperature of from 350 to 450° C.

Abstract: An asymmetric hollow-fiber gas separation membrane is made of a soluble aromatic polyimide that is composed of a specific repeating unit. The tetracarboxylic acid component of the unit has a diphenylhexafluoropropane structure and a biphenyl structure. The diamine component of the unit essentially contains diaminobenzoic acids and any of diaminodibenzothiophenes, diaminodibenzothiophene=5,5-dioxides, diaminothioxanthene-10,10-diones, and diaminothioxanthene-9,10,10-triones.

Abstract: A process of producing an asymmetric membrane of multicomponent polyimide. The process includes the steps of (1) preparing a multicomponent polyimide blend solution by mixing a polyimide component A having a number-averaged polymerization index NA and a polyimide component B having a number-averaged polymerization index NB, wherein NA and NB satisfies equation 1: 2.35×NA?2.09<NB<450×NA?1.12??1 (2) subjecting the multicomponent polyimide blend solution to further polymerization and imidation reaction, and (3) causing a phase inversion in the resulting multicomponent polyimide blend solution to form an asymmetric membrane. The polyimide component A is raw materials of polyimide A containing a fluorine atom in the chemical structure thereof and/or a polymerization and imidation reaction product of the raw materials. The polyimide component B is raw materials of polyimide B and/or a polymerization and imidation reaction product of the raw materials.

Abstract: A process of producing an asymmetric membrane of multicomponent polyimide. The process includes the steps of (1) preparing a multicomponent polyimide blend solution by mixing a polyimide component A having a number-averaged polymerization index NA and a polyimide component B having a number-averaged polymerization index NB, wherein NA and NB satisfies equation 1: 2.35×NA?2.09<NB<450×NA?1.12??1 (2) subjecting the multicomponent polyimide blend solution to further polymerization and imidation reaction, and (3) causing a phase inversion in the resulting multicomponent polyimide blend solution to form an asymmetric membrane. The polyimide component A is raw materials of polyimide A containing a fluorine atom in the chemical structure thereof and/or a polymerization and imidation reaction product of the raw materials. The polyimide component B is raw materials of polyimide B and/or a polymerization and imidation reaction product of the raw materials.

Abstract: A polyimide film made of a multicomponent polyimide comprising two or more different polyimide components including (A) a polyimide component A being raw materials of a polyimide A and/or a polyimidation product of the raw materials and (B) a polyimide component B being raw materials of a polyimide B and/or a polyimidation product of the raw materials. The polyimide components A and B are different, for example, such that the absolute difference between solubility parameter SPA of the polyimide A and solubility parameter SPB of the polyimide B, |SPB?SPA|, is 0.5 MPa1/2 or more. The polyimide film has markedly modified surface properties as compared with a polyimide film in which all the same raw materials as used in the film of the invention are randomly bonded to one another.

Abstract: An asymmetric hollow-fiber gas separation membrane is made of a soluble aromatic polyimide that is composed of a specific repeating unit. The tetracarboxylic acid component of the unit has a diphenylhexafluoropropane structure and a biphenyl structure. The diamine component of the unit essentially contains diaminobenzoic acids and any of diaminodibenzothiophenes, diaminodibenzothiophene=5,5-dioxides, diaminothioxanthene-10,10-diones, and diaminothioxanthene-9,10,10-triones.

Abstract: The present invention relates to an asymmetric hollow-fiber gas separation membrane made of a polyimide having a specific repeating unit, an improved tensile elongation at break of 15% or more as a hollow-fiber membrane itself, an oxygen gas permeation rate (P?O2) of 4.0×10?5 cm3 (STP)/cm2·sec·cmHg or more and a gas ratio of permeation rate of oxygen to nitrogen (P?O2/P?N2) of 4 or more that are measured at 50° C., a gas separation method and a gas separation membrane module using the asymmetric hollow-fiber gas separation membrane. In addition, the present invention relates to an asymmetric hollow-fiber gas separation membrane obtained by heat-treating the asymmetric hollow-fiber gas separation membrane at a maximum temperature of from 350 to 450° C. The asymmetric hollow-fiber gas separation membrane has sufficient mechanical strength even after the heat-treatment at a maximum temperature of from 350 to 450° C.

Abstract: An object of the present invention is to provide a humidifying apparatus capable of improving the humidification efficiency while lowering the pressure loss of gas even when a low-pressure gas is used, and is suitably usable for fuel cells. The present invention relates to a humidifying apparatus for fuel cells, fabricated by loading a hollow fiber membrane element into a container such that the space communicating with the hollow side of the hollow fiber membranes is isolated from the space communicating with the outer side of the hollow fiber membranes, wherein (a) the inner diameter of the hollow fiber membrane is larger than 400 ?m, (b) the water vapor permeation rate (P?H2O) of the hollow fiber membranes is 0.5×10?3 cm3 (STP)/cm2·sec·cm Hg or more, (c) the ratio (P?H2O/P?O2) of the water vapor permeation rate to the oxygen gas permeation rate of the hollow fiber membranes is 10 or more, and (d) the elongation at tensile break of the hollow fiber membranes after hot water treatment in hot water at 100° C.

Abstract: A process of producing an asymmetric membrane of multicomponent polyimide. The process includes the steps of (1) preparing a multicomponent polyimide blend solution by mixing a polyimide component A having a number-averaged polymerization index NA and a polyimide component B having a number-averaged polymerization index NB, wherein NA and NB satisfies equation 1: 2.35×NA?2.09<NB<450×NA?1.12??1 (2) subjecting the multicomponent polyimide blend solution to further polymerization and imidation reaction, and (3) causing a phase inversion in the resulting multicomponent polyimide blend solution to form an asymmetric membrane. The polyimide component A is raw materials of polyimide A containing a fluorine atom in the chemical structure thereof and/or a polymerization and imidation reaction product of the raw materials. The polyimide component B is raw materials of polyimide B and/or a polymerization and imidation reaction product of the raw materials.