Ube Industries, Inc.

Toshimune Yoshinaga

Kenji Fukunaga

Harutoshi Hoshino

Yoji Kase

Yoshihiro Kusuki

Tomonori Kanougi

Nozomu Tanihara

Hiroshi Shimazaki

Hidetomo Ashitaka

Hiroshi Yasuno

Denichi Oda

Tsunetomo Nakano

Shunsuke Nakanishi

Yutaka Kanetsuki

Kenji Ito

Shinji Asanuma

Makoto Nakamura

Akira Nagasaka

Hiroshi Uchida

Minoru Shigemura

Ryoichi Takada

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 (T) 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.

Asymmetric gas separation membrane and method for separating methanol from mixed organic vapor using the same

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&#xb0; 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. In the general formula (1), 20 to 80 mol % of A is a tetravalent unit based on a biphenyl structure represented by formula (2), 20 to 80 mol % of A is a tetravalent unit based on a diphenylhexafluoropropane structure represented by formula (3), and 0 to 30 mol % of A is a tetravalent unit based on a phenyl structure represented by formula (4); and in the general formula (1), 30 to 70 mol % of R is a divalent unit represented by formula (5) and/or formula (6), and 30 to 70 mol % of R is a divalent unit having one or two other aromatic rings than formula (5) or (6),  

Solvent-resistant asymmetric hollow fiber gas separation membrane, and method for production thereof

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. 

Asymmetric gas separation membrane and process for gas separation

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&#x2032;-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.

Polyimide gas separation membrane and gas separation method

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 SPof the polyimide A and solubility parameter SPof the polyimide B, |SP-SP|, is 0.5 MPaor 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.

Polyimide film made of multicomponent polyimide and process of producing the same

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 Nand a polyimide component B having a number-averaged polymerization index N, wherein Nand Nsatisfies equation 1:2.35&#xd7;&#x3c;450&#xd7;&#x2003;&#x2003;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.

Method for manufacturing polyimide asymmetric membrane, and polyimide asymmetric membrane

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') of 4.0&#xd7;10cm(STP)/cm&#xb7;sec&#xb7;cmHg or more and a gas ratio of permeation rate of oxygen to nitrogen (P&#x2032;/P&#x2032;) of 4 or more that are measured at 50&#xb0; 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&#xb0; 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&#xb0; C.

Asymmetric hollow-fiber gas separation membrane, gas separation method and gas separation membrane module

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.

Asymmetric hollow fiber gas separation membrane and gas separation method

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 Nand a polyimide component B having a number-averaged polymerization index N, wherein Nand Nsatisfies equation 1:2.35&#xd7;N&#x3c;N&#x3c;450&#xd7;N&#x2003;&#x2003;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.

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 &#x3bc;m, (b) the water vapor permeation rate (P') of the hollow fiber membranes is 0.5&#xd7;10cm(STP)/cm&#xb7;sec&#xb7;cm Hg or more, (c) the ratio (P&#x2032;/P&#x2032;) 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&#xb0; C. for 50 hours is 80% or more of that before the hot water treatment; particularly, the present invention relates to a humidifying apparatus for fuel cells where, if the effective length of the hollow fiber membrane element is L and the inner diameter of the container into which the hollow fiber membrane element is loaded is D, L/D is 1.8 or more.

Fuel cell-use humidifier

An asymmetric membrane is formed using a mixture of two or more different polymers including at least one type of polyimide. It is thereby possible to produce a gas separation membrane with low permeation resistance (a high permeation rate) for permeate gases passing through the porous layer of the membrane, which also maintains a practical level of mechanical strength of the membrane and has excellent water resistance and hot water resistance.

Gas separation membrane and method for its use

A gas separating asymmetric membrane such as a gas separating asymmetric hollow fiber comprises an aromatic polyimide comprising recurring units of the formulae (I) and (II): ##STR1## wherein A.sup.1 is a tetravalent unit having a diphenylhexafluoropropane structure, A.sup.2 is a tetravalent unit having a benzene structure, and A.sup.3 is a divalent aromatic unit which is a unit derived from a sulfur atom-containing diamine such as diaminodibenzothiophene, diaminodiphenylenesulfone, diaminothioxanthene-5,5-dioxide or diaminothioxanthone-5,5-dioxide. The aromatic polyimide contains the recurring unit of the formula (I) in an amount of 40 to 90 molar % and the recurring unit of the formula (II) in an amount of 10 to 40 molar %. Further, a process for the preparation of the gas separating asymmetric hollow fiber membrane is also disclosed.

Gas separating asymmetric membrane

An aromatic polyimide double layered hollow filamentary membrane having an excellent heat resistance, chemical resistance, pressure-resistance, and gas-permeating and separating properties comprises (A) an aromatic imide polymer hollow filamentary microporous inner layer and (B) an aromatic imide polymer tubular filamentary asymmetric outer layer composed of (a) tubular filamentary microporous intermediate layer covering and united with the outside surface of the inner layer (A) and (b) a thin dense outside surface layer covering and united with the intermediate layer (a).

Aromatic polyimide double layered hollow filamentary membrane and

A photosetting composition useful as a coating varnish comprising a modified, epoxidized butadiene polymer, at least one photopolymerizable monomer and a photosensitizer, the modified, epoxidized butadiene polymer comprising (1) an epoxidized butadiene polymer backbone group, (2) 5 to 50 aromatic or cyclocyclic polybasic carboxylic ester side chain groups per 100 butadiene units, each having at least one acryloyl or methacryloyl terminal group and a linking group formed by a reaction between a carboxylic acid radical in the polybasic carboxylic ester and an epoxy radical in the epoxidized butadiene polymer and, optionally, (3) 0 to 50 phosphoric ester additional side chain groups per 100 butadiene units, each having a linking group formed by a reaction between a hydroxyl radical attached to a P atom in the phosphoric ester and an epoxy radical in the epoxidized butadiene polymer.

Photocurable acrylic phosphate esters of epoxidized polybutadiene

Carbon fibers having excellent modulus of elasticity and tensile strength are produced in a high yield by a process wherein polybutadiene fibers are prepared by melt-spinning polybutadiene having at least 85% of vinyl structure, a melting point of at least 100.degree. C and a reduced viscosity of 0.3 to 1.2 dl/g; the fibers are then treated in a solution or suspension of a Lewis acid in an inert organic liquid, whereby the pollybutadiene is cyclized and cross-linked; the polybutadiene fibers treated as mentioned above are further treated in a melted sulphur or a sulphur-containing solution at a temperature of 170 to 300.degree. C, whereby the cyclized and cross-linked polybutadiene is dehydrogenated and aromatized; and the fibers treated as mentioned above are carbonized by raising the temperature thereof to 750.degree. C to 3000.degree. C to form carbon fibers or graphite fibers. If so desired, the ordinary carbon fibers which have been produced at 750 to 1500.degree. C, can be converted to graphite fibers by heating them to a temperature of 1500 to 3000.degree. C.

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Chiba, Japan

Toshimune Yoshinaga