Hydrogen separation membrane, method for producing hydrogen separation membrane, and method for producing hydrogen gas

Abstract

Provided is a hydrogen separation membrane containing a resin and hydrogen storage alloy particles. In the hydrogen separation membrane, the hydrogen permeability measured at a measurement temperature of 80°C and a supply pressure of 1 atm according to the differential pressure method using the apparatus described in JIS K 7126-1:2006 is 7.5×10-11 mol / m2·s·Pa or greater, and the selectivity, which is expressed in formula (1) below as the ratio of the hydrogen permeability to carbon dioxide permeability measured at a measurement temperature of 80°C and a supply pressure of 1 atm according to the differential pressure method using the apparatus described in JIS K 7126-1:2006, is 50 or greater.　Formula (1): Selectivity = hydrogen permeability [mol / m2·s·Pa] / carbon dioxide permeability [mol / m2·s·Pa]

Description

Hydrogen separation membrane, method for producing hydrogen separation membrane, and method for producing hydrogen gas

[0001] The present invention relates to a hydrogen separation membrane, a method for producing a hydrogen separation membrane, and a method for producing hydrogen gas.

[0002] Hydrogen gas is used as a fuel for, for example, fuel cells and hydrogen engines. Various methods are known for producing hydrogen gas, but in all of them, hydrogen gas is produced as a mixed gas containing hydrogen and other gases such as carbon dioxide. Therefore, before use, the mixed gas is purified to extract high-purity hydrogen gas.

[0003] A method using a hydrogen separation membrane is known as a method for extracting high-purity hydrogen gas from a mixed gas. One type of hydrogen separation membrane is a metal membrane made of a metal having hydrogen storage capacity (see, for example, Patent Document 1). Such metal membranes have problems not only with their high cost but also with their susceptibility to embrittlement due to hydrogen.

[0004] In response to this, hydrogen separation membranes have been proposed that combine a resin with a hydrogen storage alloy or a compound having hydrogen storage capacity. For example, Patent Document 2 discloses a hydrogen separation membrane having a separation function layer on a support membrane, the separation function layer containing a crosslinked polyamide and a compound having hydrogen storage capacity. This document describes that the separation function layer is formed by applying a solution containing a polyfunctional amine and a compound having hydrogen storage capacity onto the support membrane, and then further applying a solution containing a polyfunctional acid halide to cause interfacial polymerization of the polyfunctional amine and the polyfunctional halide.

[0005] Patent Document 3 discloses a hydrogen separation membrane made of a hydrogen storage alloy powder plated with Cu or Ni and a polymer compound that does not allow impurity gases other than hydrogen to pass through. This document describes that the hydrogen separation membrane can be obtained by forming the plated hydrogen storage alloy powder into a membrane using a press or the like, and then impregnating the polymer compound between the powder particles.

[0006] Non-Patent Document 1 describes hydrogen storage alloy powder LaNi ５and polyethylene. In this document, the hydrogen separation membrane is made of polyethylene and LaNi ５ It is described that the mixture can be obtained by mixing the above components in a ball mill and then forming a film by hot pressing.

[0007] Japanese Patent Application Laid-Open No. 2023-39770 Japanese Patent Application Laid-Open No. 2022-54573 Japanese Patent Application Laid-Open No. 4-44604

[0008] DV Strugova et. al., International Journal of Hydrogen Energy, 43(2018) 12146-12152

[0009] However, the hydrogen separation membranes of Patent Document 3 and Non-Patent Document 1 both have a large thickness because hydrogen storage alloy powder is formed into a membrane by pressing, and therefore have the problem of a low hydrogen permeation rate and low hydrogen permeability throughout the membrane.

[0010] On the other hand, the separation functional layer of Patent Document 2 is formed by coating, so the membrane thickness can be relatively thin, and it is thought that a certain level of hydrogen permeability can be obtained. However, in Patent Document 2, the separation functional layer is formed by interfacially polymerizing a polyfunctional amine and a polyfunctional halide in the presence of a compound having hydrogen storage capacity, so the amount of the compound having hydrogen storage capacity could not be increased beyond a certain level in order to avoid interfacial polymerization. Furthermore, the resulting separation functional layer had insufficient selectivity (hydrogen permeability / carbon dioxide permeability). Thus, conventional hydrogen separation membranes that combine a resin with a hydrogen storage alloy or a compound having hydrogen storage capacity did not achieve both high hydrogen permeability and high selectivity.

[0011] The present invention has been made in view of the above circumstances, and aims to provide a hydrogen separation membrane that achieves both high hydrogen permeability and high selectivity, a method for manufacturing a hydrogen separation membrane, and a method for manufacturing hydrogen gas.

[0012] The present invention relates to the following hydrogen separation membrane, a method for producing a hydrogen separation membrane, and a method for producing hydrogen gas: [1] A hydrogen separation membrane comprising a resin and hydrogen storage alloy particles, which has a hydrogen permeability of 7.5 × 10 measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere. －１１ mol / m ２ A hydrogen separation membrane having a selectivity of 50 or more, expressed as the ratio of the hydrogen permeability to the carbon dioxide permeability measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere, as shown in the following formula (1): Selectivity = hydrogen permeability [mol / m ２ s Pa] / carbon dioxide permeability [mol / m ２ [2] The hydrogen separation membrane according to [1], wherein the selectivity is 150 or more. [3] The hydrogen separation membrane has an average volume resistivity of 1×10 at any five points under 23° C. and 80% RH. ９[4] The hydrogen separation membrane according to any one of [1] to [3], wherein, when a field of view is taken in a range of 100 to 150 μm in a direction perpendicular to the membrane thickness direction in a cross section of the hydrogen separation membrane and the center of the membrane thickness is included in the membrane thickness direction, and the area ratio of regions of elements constituting the hydrogen storage alloy particles in the field of view to the total area of ​​the hydrogen separation membrane, obtained by scanning electron microscope-energy dispersive X-ray spectroscopy, is defined as the area ratio [%] of the hydrogen storage alloy particles, the average area ratio of the hydrogen storage alloy particles when measured at five arbitrary non-overlapping fields is 20% to 70%. [5] The hydrogen separation membrane according to any one of [1] to [4], wherein the resin contains a binder resin that binds the hydrogen storage alloy particles, and the binder resin contains at least one resin selected from the group consisting of a fluorine-based resin, a diene-based rubber, polyethylene oxide (PEO), a polyolefin resin, a urethane resin, a phenolic resin, a polyether, a polyamide, a polyester, a vinyl resin, and an acrylic acid-based copolymer. [6] The hydrogen separation membrane according to any one of [1] to [5], wherein the resin contains a fluorine-based resin. [7] The hydrogen separation membrane according to [6], wherein the fluorine content measured by combustion ion chromatography is 3 mass% or more and 40 mass% or less, based on the total mass of the hydrogen separation membrane. [8] The hydrogen separation membrane according to [6] or [7], wherein, when a field of view is taken in a range of 100 to 150 μm in a direction perpendicular to the membrane thickness direction and the center of the membrane thickness of the hydrogen separation membrane in the membrane thickness direction, the cross section of the hydrogen separation membrane is measured by scanning electron microscope-energy dispersive X-ray spectroscopy, and the area ratio of fluorine regions in the field of view to the total area of ​​the hydrogen separation membrane in the field of view is defined as the area ratio of the fluororesin [%], and the average area ratio of the fluororesin measured at any five non-overlapping fields is 10% to 65%. [9] The hydrogen separation membrane according to any one of [1] to [8], wherein the resin comprises a cured product of a curable resin composition containing a curable resin.

[10] The hydrogen separation membrane according to [9], wherein the cured product has a glass transition temperature of 80° C. or higher.

[11] The density of the hydrogen separation membrane is 2.5 g / cm. ３ The hydrogen separation membrane according to any one of [1] to

[10] , wherein the thickness is 120 μm or less.

[12] The hydrogen separation membrane according to any one of [1] to

[10] , wherein the thickness is 120 μm or less.

[13] A method for producing a hydrogen separation membrane according to any one of [1] to

[10] , comprising the steps of: preparing a porous membrane containing hydrogen storage alloy particles and a binder resin that binds the hydrogen storage alloy particles; and filling voids in the porous membrane with a curable resin composition containing a curable resin, and curing the composition.

[14] The method for producing a hydrogen separation membrane according to

[13] , wherein the step of preparing the porous membrane comprises the steps of obtaining a solution containing the binder resin and a solvent in which the binder resin can be dispersed or dissolved, and mixing the solution with the hydrogen storage alloy particles, followed by molding and drying to obtain the porous membrane.

[15] A method for producing a hydrogen separation membrane according to

[13] or

[14] , wherein the binder resin contains at least one resin selected from the group consisting of a fluorine-based resin, a diene-based rubber, polyethylene oxide (PEO), a polyolefin resin, a urethane resin, a phenolic resin, a polyether, a polyamide, a polyester, a vinyl resin, and an acrylic acid-based copolymer.

[16] A method for producing hydrogen gas, comprising the steps of: supplying a mixed gas containing hydrogen and a gas other than hydrogen to a space in contact with one side of the hydrogen separation membrane according to any one of [1] to

[10] ; and recovering a hydrogen-containing gas from the space in contact with the other side of the hydrogen separation membrane.

[0013] According to the present invention, it is possible to provide a hydrogen separation membrane that achieves both high hydrogen permeability and high selectivity, a method for producing a hydrogen separation membrane, and a method for producing hydrogen gas.

[0014] Fig. 1 is a schematic cross-sectional view of a hydrogen separation membrane according to one embodiment of the present invention. Figs. 2A and 2B are schematic cross-sectional views showing a method for manufacturing a hydrogen separation membrane according to one embodiment of the present invention. Figs. 3A to 3C are monochrome processed SEM-EDX analysis images of the cross-section of a fabricated sample.

[0015] The inventors' investigations revealed that in the hydrogen separation membrane obtained by applying a mixed solution of hydrogen storage alloy particles and a matrix resin, as shown in Patent Document 2, the hydrogen storage alloy particles are dispersed throughout the membrane and do not have a densely connected structure, which is thought to be why sufficient selectivity cannot be obtained.

[0016] In response to this, the present inventors have conducted further studies and have found that, as one embodiment, a hydrogen separation membrane having high hydrogen permeability and high selectivity can be obtained by, for example, producing a porous membrane containing hydrogen storage alloy particles and a resin (e.g., a binder resin) that binds the hydrogen storage alloy particles, and then further filling voids formed between the hydrogen storage alloy particles in the porous membrane with another resin (e.g., a matrix resin).

[0017] The reason for this is unclear, but is thought to be as follows. The hydrogen separation membrane obtained by the above method has a structure in which hydrogen storage alloy particles are tightly bound together by the binder resin. Specifically, the hydrogen storage alloy particles are tightly bound together in three dimensions by the binder resin, forming long paths connecting the hydrogen storage alloy particles. Hydrogen permeates through such paths, promoting hydrogen permeation. This increases hydrogen permeability while preventing gases other than hydrogen from permeating the hydrogen storage alloy particles, thereby improving selectivity. Furthermore, filling the voids in the porous membrane with a matrix resin makes it even more impervious to gases other than hydrogen. Furthermore, as described above, membrane formation by coating allows for even thinner membranes. This allows for greater hydrogen permeability and further improved selectivity.

[0018] The hydrogen separation membrane thus obtained contains a resin and hydrogen storage alloy particles. The hydrogen permeability of the hydrogen separation membrane measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere is 7.5 × 10 －１１ mol / m ２s Pa or more, and the selectivity, expressed as the ratio of the hydrogen permeability to the carbon dioxide permeability measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere, is 50 or more. Equation (1): Selectivity = hydrogen permeability [mol / m ２ s Pa] / carbon dioxide permeability [mol / m ２ · s · Pa]

[0019] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. Furthermore, in this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0020] 1. Hydrogen Separation Membrane Figure 1 is a schematic cross-sectional view showing the structure of a hydrogen separation membrane 10 according to one embodiment of the present invention.

[0021] 1 , the hydrogen separation membrane 10 includes a resin 11 and hydrogen storage alloy particles 12. In this embodiment, the hydrogen separation membrane 10 includes a matrix resin 11A, hydrogen storage alloy particles 12 dispersed in the matrix resin 11A, and a binder resin 11B present between the hydrogen storage alloy particles 12. Note that, although this embodiment will be described using an example in which the resin 11 includes the matrix resin 11A and the binder resin 11B, the present invention is not limited to this, and the structure of the hydrogen separation membrane and the composition and type of resin are not limited as long as the above-mentioned hydrogen permeability and selectivity are satisfied.

[0022] 1-1. Matrix Resin 11A The type of matrix resin is not particularly limited, but it is preferable that the matrix resin is a resin that is difficult for gases other than hydrogen gas (for example, carbon dioxide) to permeate.

[0023] For example, the carbon dioxide permeability coefficient of the matrix resin is preferably lower than that of the porous film containing the hydrogen storage alloy particles and the binder resin bound thereto. Specifically, the carbon dioxide permeability coefficient of the matrix resin measured by a differential pressure method in accordance with JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere is 5.5 × 10 －１６mol m / m ２ s Pa or less, and preferably 1.5×10 －１７ mol m / m ２ The lower limit of the carbon dioxide permeability coefficient of the matrix resin 11A is not particularly limited, but is preferably 0 mol m / m ２ s Pa or more, and 1.0 × 10 －１７ mol m / m ２ .s.Pa or more.

[0024] The carbon dioxide permeability coefficient of a matrix resin can be measured by the differential pressure method in accordance with JIS K 7126-1:2006. Specifically, it can be measured by the following procedure. 1) The matrix resin is formed into a film to be used as a sample piece. The film thickness of the sample piece is measured in advance. 2) The carbon dioxide permeability of the sample piece is measured by the differential pressure method. The measuring device used is one described in JIS K 7126-1:2006, such as GTR-21A-A, GTR-21A-B, or GTR-30XA manufactured by GTR Tech Co., Ltd. The measurement temperature is 80°C, and the supply pressure is 0.1 MPa (differential pressure 0.1 MPa). 3) The measured carbon dioxide permeability [mol / m ２ s Pa] was multiplied by the film thickness of the sample piece to obtain the carbon dioxide permeability coefficient [mol m / m ２ ・s・Pa] is calculated.

[0025] The matrix resin may be a thermoplastic resin composition containing a thermoplastic resin or a curable resin composition containing a curable resin. From the viewpoints of improving the strength of the hydrogen separation membrane and facilitating impregnation, the matrix resin preferably contains a cured product of a curable resin composition containing a curable resin.

[0026] The curable resin contained in the curable resin composition may be a photocurable resin or a thermosetting resin. Among them, from the viewpoints of easily obtaining a cured product with high gas barrier properties and facilitating curing and molding, it is preferable that the curable resin contains a thermosetting resin.

[0027] The glass transition temperature of the matrix resin containing the cured product of the curable resin composition is preferably equal to or higher than the ambient temperature at which the hydrogen separation membrane is used. At temperatures higher than the glass transition temperature, the molecules of the matrix resin tend to be mobile, and the gas barrier properties tend to deteriorate. In contrast, when the glass transition temperature of the matrix resin is equal to or higher than the ambient temperature at which the membrane is used, the gas barrier properties can be better maintained even at the ambient temperature at which the membrane is used, and high selectivity can be better maintained. Specifically, the glass transition temperature of the matrix resin containing the cured product of the curable resin composition is preferably 80°C or higher, and more preferably 80°C or higher and 150°C or lower. The glass transition temperature (Tg) of the matrix resin is a value measured in accordance with JIS K 7121:2012 using a differential scanning calorimeter (e.g., DSC1 manufactured by Mettler Toledo) at a heating rate of 20°C / min.

[0028] Examples of thermosetting resins include epoxy resins, phenolic resins, melamine resins, maleic acid resins, maleimide resins, urea resins, guanamine resins, aniline resins, urethane resins, oxazine resins, oxazoline resins, imide resins, acrylic resins having functional groups, and silicone resins having functional groups. Examples of functional groups possessed by acrylic resins and silicone resins include hydroxyl groups, methylol groups, carboxyl groups, epoxy groups, and amino groups. Of these, epoxy resins are preferred. The epoxy resin may be an aliphatic epoxy resin, an alicyclic epoxy resin, or an aromatic epoxy resin.

[0029] The epoxy resin may be an epoxy resin having two or more epoxy groups in one molecule, or an epoxy resin having three or more epoxy groups in one molecule. Among them, from the viewpoint of increasing the crosslink density and making it more impervious to gases other than hydrogen, an epoxy resin having three or more epoxy groups in one molecule is preferred.

[0030] Examples of epoxy resins having three or more epoxy groups in one molecule include phenol novolac epoxy resins, cresol novolac epoxy resins, triphenylmethane epoxy resins, dicyclopentadiene epoxy resins, bisphenol A epoxy resins, and tetramethylbisphenol F epoxy resins.

[0031] Among these, it is preferable to use an epoxy resin having three or more epoxy groups in one molecule and a glycidylamine moiety, from the viewpoint of easily forming a cured product having good adhesion to the hydrogen storage alloy particles and the binder resin.

[0032] Examples of epoxy resins having three or more epoxy groups in one molecule and having a glycidyl amine moiety include epoxy resins having a glycidyl amine moiety and further having a glycidyl ether moiety, which are derived from a compound having two or more amino groups, or one or more amino groups and one or more hydroxyl groups.

[0033] Specific examples include epoxy resins having a glycidylamine moiety derived from a xylylenediamine such as meta-xylylenediamine or para-xylylenediamine, epoxy resins having a glycidylamine moiety derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamine moiety derived from diaminodiphenylmethane, epoxy resins having a glycidylamine moiety and a glycidyl ether moiety derived from para-aminophenol, and epoxy resins having a glycidylamine moiety and a glycidyl ether moiety derived from 4-amino-3-methylphenol.

[0034] The content of the curable resin in the curable resin composition is, for example, preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 80% by mass or less, relative to the total mass of the curable resin composition.

[0035] The curable resin composition may further contain a curing agent as needed. The curing agent is not particularly limited as long as it can cure the curable resin. For example, when the thermosetting resin is an epoxy resin, examples of the curing agent include acid anhydride curing agents (e.g., phthalic anhydride, maleic anhydride, nadic anhydride, methylnadic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and succinic anhydride), amine curing agents, phenolic curing agents (e.g., bisphenol A, bisphenol F, and thiodiphenol), and polyaddition-type curing agents such as mercaptan curing agents, catalyst-type curing agents such as imidazole, and boric acid complex-type curing agents. Among these, amine curing agents are preferred from the viewpoint of high adhesion and heat resistance.

[0036] As the amine curing agent, any commonly used one can be used without any particular limitation, and commercially available ones may also be used. Among them, from the viewpoint of curability, a polyfunctional amine curing agent having two or more functional groups is preferable. The polyfunctional amine curing agent may be either an aliphatic polyamine or an aromatic polyamine. From the viewpoint of high gas barrier properties and heat resistance, an aromatic polyamine is preferable.

[0037] Examples of aromatic polyamines include phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone, diaminophenyl benzoate, diaminodimethoxybiphenyl, 1,3-bis(3-aminophenoxy)benzene, diethyltoluenediamine, 2,2-bis[4-(4-aminophenoxyphenoxy)phenyl]propane (BAPP), and diaminonaphthalene.

[0038] The content of the curing agent in the curable resin composition is not particularly limited, and is preferably, for example, from 10% by mass to 90% by mass, and more preferably from 20% by mass to 80% by mass, relative to the total mass of the thermosetting resin.

[0039] The content of the matrix resin in the hydrogen separation membrane is not particularly limited, but is preferably 4% by mass or more and 16% by mass or less relative to the total mass of the hydrogen separation membrane. When the content of the matrix resin is 4% by mass or more, the membrane becomes more impervious to gases other than hydrogen gas, thereby further increasing selectivity. When the content of the matrix resin is 16% by mass or less, the content of the hydrogen storage alloy particles can be increased, thereby further increasing hydrogen permeability. From the same perspective, the content of the matrix resin is more preferably 4% by mass or more and 10% by mass or less. The content of the matrix resin in the hydrogen separation membrane can be calculated from the area proportion of each component and the density of each component when a cross section of the hydrogen separation membrane is analyzed by SEM-EDX.

[0040] 1-2. Binder Resin 11B The binder resin is present between the hydrogen storage alloy particles and binds the hydrogen storage alloy particles together.

[0041] The binder resin is not particularly limited as long as it binds hydrogen storage alloy particles together. Examples of such binder resins include fluorine-based resins, diene-based rubbers (e.g., styrene-butadiene rubber (SBR)), polyethylene oxide (PEO), polyolefin-based resins (e.g., ethylene-based resins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl alcohol copolymers, propylene-based resins such as polypropylene, and methylpentene-based resins such as polymethylpentene), urethane resins, phenolic resins, polyethers (e.g., polyoxymethylene, polyoxyethylene, polyethersulfone, and polyetherketone), polyamides (e.g., nylon 6, nylon 66, and aramid resins), polyesters (e.g., polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthate, glyptal resins, and polylactic acid), vinyl resins (e.g., polyvinyl chloride, polyvinyl acetate, and polyvinyl alcohol), and acrylic acid-based copolymers (e.g., ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers). These may be included singly or in combination of two or more.

[0042] Among these, fluorine-based resins, styrene butadiene rubber (SBR) and polyethylene oxide (PEO) are preferred because of their high binding ability to hydrogen storage alloy particles, and fluorine-based resins are more preferred.

[0043] The type of fluorine-based resin is not particularly limited, and may be a homopolymer of a fluorine-containing monomer such as vinylidene fluoride (VDF) or tetrafluoroethylene (TFE), or a copolymer of the fluorine-containing monomer and a monomer copolymerizable therewith. Examples of fluorine-based resins include polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).

[0044] The content of the binder resin in the hydrogen separation membrane is not particularly limited, but is preferably 3% by mass or more and 40% by mass or less, more preferably 4% by mass or more and 20% by mass or less, and even more preferably 4% by mass or more and 10% by mass or less, relative to the total mass of the hydrogen separation membrane. When the content of the binder resin is 3% by mass or more, the hydrogen storage alloy particles can be more effectively bound together, thereby further increasing the hydrogen permeability. When the content of the binder resin is 40% by mass or less, the decrease in hydrogen permeability due to poor contact between the hydrogen storage alloy particles can be further suppressed. The content of the binder resin in the hydrogen separation membrane can be calculated from the area proportion of each component and the density of each component obtained by analyzing a cross section of the hydrogen separation membrane using SEM-EDX.

[0045] From the same viewpoint, the content of the binder resin in the hydrogen separation membrane is preferably 4% by mass or more and 45% by mass or less, more preferably 4% by mass or more and 20% by mass or less, and even more preferably 4% by mass or more and 10% by mass or less, based on the total amount of the hydrogen storage alloy particles and the binder resin. The total amount of the hydrogen storage alloy particles and the binder resin is preferably 80% by mass or more and more preferably 90% by mass or more and 95% by mass or less, based on the total mass of the hydrogen separation membrane. The total amount of the hydrogen storage alloy particles and the binder resin can be calculated from the area proportion of each component and the density of each component when a cross section of the hydrogen separation membrane is analyzed by SEM-EDX.

[0046] (Fluorine Content by Combustion Ion Chromatography) When the hydrogen separation membrane contains a fluororesin as a binder resin, the fluorine content measured by combustion ion chromatography is preferably 3% by mass or more and 40% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 8% by mass or less, relative to the total mass of the hydrogen separation membrane. When the fluorine content is 3% by mass or more, a predetermined amount or more of the fluororesin is contained, which can better bind the hydrogen storage alloy particles and further increase the hydrogen permeability. When the fluorine content is 40% by mass or less, the amount of the fluororesin is not excessive, which can further suppress a decrease in hydrogen permeability.

[0047] The fluorine content of the hydrogen separation membrane can be determined by measuring the fluorine content at three arbitrarily selected points by combustion ion chromatography and calculating the average value. The measurement conditions can be as follows: [Automatic sample combustion apparatus] Apparatus: AQF-2100H (manufactured by Nitto Seiko Analytech Co., Ltd.) (Electric furnace unit) Decomposition temperature: Inlet: 900°C, Outlet: 1000°C Ar flow rate: 200 mL / min O ２ Flow rate: 400 mL / min (gas absorption unit) Absorption solution composition: 10 ml of ultrapure water [Ion chromatograph] Apparatus: IC-2010 (manufactured by Tosoh Corporation) Separation column: TSKgel Super IC-Anion HS (4.6 mm ID x 100 mm) Eluent: 9.0 mM NaHCO ３ +1.0 mM Na ２ CO ３ Flow rate: 1.0 mL / min Column temperature: 40°C

[0048] (Area Proportion of Fluorine-Based Resin by SEM-EDX Measurement) Furthermore, when the hydrogen separation membrane contains a fluorine-based resin as a binder resin, when a field of view is taken in a cross section of the hydrogen separation membrane so that a range of 100 to 150 μm falls within the direction perpendicular to the membrane thickness direction and so that the center of the membrane thickness falls within the membrane thickness direction, the area proportion of the fluorine region obtained by scanning electron microscope-energy dispersive X-ray spectroscopy to the total area of ​​the hydrogen separation membrane in the field of view is taken as the area proportion of the fluorine-based resin [%], the average area proportion of the fluorine-based resin is preferably 10% or more and 65% or less, more preferably 10% or more and 40% or less, and even more preferably 10% or more and 20% or less.

[0049] The area ratio of the fluororesin in the cross section can be measured using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX). Specifically, the measurement can be performed using the following procedure. (1) Sample Preparation: The hydrogen separation membrane is cut into a 1 mm x 5 mm strip, and metallic Os is vapor-deposited to ensure electrical conductivity. The cross section of the hydrogen separation membrane is then extracted by ion milling (accelerating voltage: 4 kV). (2) SEM-EDX Measurement: Next, a field of view is taken so that it covers a range of 100 to 150 μm in the direction perpendicular to the membrane thickness direction and the center of the membrane thickness is located in the membrane thickness direction. Next, when the field of view is analyzed using a scanning electron microscope-energy dispersive X-ray spectroscopy, the area ratio [%] of the region where fluorine is detected relative to the total area of ​​the hydrogen separation membrane in the field of view is measured. This measurement is performed at five random locations where the fields of view do not overlap, and the average value is calculated.

[0050] 1-3. Hydrogen Storage Alloy Particles 12 The hydrogen storage alloy is not particularly limited as long as it has the ability to store hydrogen, including conventionally known hydrogen storage alloys.

[0051] The hydrogen storage alloy is not particularly limited, but for example, AB ５ Type (rare earth) alloy, AB / A ２ B type alloy, AB ２ AB type (Laves phase) alloys. ５ Examples of rare earth alloys include LaNi５ , LaNi ４ Cu, LaNi ４ Al, LaNi ２．５ Co ２．５ , La ０．８ Nd ０．２ Ni ２ Co ３ , La ０．７ Nd ０．２ Ti ０．１ Ni ２．５ Co ２．４ Al ０．１ , La ０．８ Nd ０．２ Ni ２．５ Co ２．４ Si ０．１ , La ０．９ Zr ０．１ Ni ４．５ Al ０．５ , MmNi ５ (Mm = Mischmetal), MmNi ３．５５ Co ０．７５ Mn ０．４ Al ０．３ , MmNi ４．２ Mn ０．６ Al ０．２ , MmNi ３ Co １．５ Al ０．５ , MmB ｘ (x=4.55 to 4.76, B=Ni, Co, Mn, Al). ２ Examples of B-type alloys include TiNi, Ti ２ Ni, TiMn ２ , Ti ２ Ni-TiNi-based multi-component alloys (partial replacement of Ni with V, Cr, Zr, Mn, Co, Cu, Fe, etc.); Ti １－ｙ Zr ｙ Ni ｘ (x=0.5-1.45, y=0-1), TiFe, TiCo, ZrCo, ZrNi, Mg ２ Ni, Zr ２ Ni is included. ２ Examples of Laves phase alloys include Ti ２－ｘ Zr ｘ V ４－ｙ Ni ｙ , Ti １－ｘ Cr ｘ V ２－ｙNi ｙ , ZrV ０．４ Ni １．６ , ZrMn ０．６ Cr ０．２ Ni １．２ , Ti １７ Zr １５ V ２２ Ni ３９ Cr ７ , LaNi ２ , CeNi ２ , HfMn ２ , NbZn ２ , ScFe ２ , TiCr ２ , ZrNi ２ , ZrCr ２ , LaMg ２ , LaAl ２ , CaAl ２ , CeCo ２ , TiCo ２ , YNi ２ , ZrV ２ , ZrCo ２ , ZrZn ２ , BaMg ２ , CaLi ２ , CaMg ２ , NbFe ２ , TiMn ２ , ZrMn ２ , ZrAl ２ , ZrCo ２ These hydrogen storage alloys may be contained alone or in combination of two or more.

[0052] In this embodiment, from the viewpoint of fast hydrogen absorption and desorption, AB ５ Type (rare earth) alloys are preferred.

[0053] The shape of the hydrogen storage alloy is not particularly limited, but is preferably particulate. Furthermore, particulate shapes are not limited to spherical shapes, and include irregular shapes such as those obtained by pulverization. The average particle size of the hydrogen storage alloy particles can be, for example, 0.01 μm to 2 mm, preferably 0.1 μm to 2 mm, and more preferably 0.1 μm to 100 μm. When the average particle size of the hydrogen storage alloy particles is 0.01 μm or more, handling can be improved, for example, when mixing with a binder resin to prepare a slurry. When the average particle size of the hydrogen storage alloy particles is 2 mm or less, the hydrogen storage alloy particles are more likely to aggregate with each other, making it easier to form a densely aggregated structure in the hydrogen separation membrane. The average particle size of the hydrogen storage alloy particles is the particle size (median size (D50)) at an integrated value of 50% in the volume distribution determined by a laser diffraction / scattering method, and can be measured, for example, by a Microtrac particle size distribution analyzer (e.g., Microtrac particle size distribution analyzer MT3300EXII manufactured by Microtrac-Bell).

[0054] The content of hydrogen storage alloy particles in the hydrogen separation membrane is not particularly limited, but is preferably 55 mass% or more, more preferably 60 mass% or more, and even more preferably 80 mass% to 92 mass% relative to the total mass of the hydrogen separation membrane. When the content of hydrogen storage alloy particles is 55 mass% or more, hydrogen permeability can be further increased. When the content of hydrogen storage alloy particles is 92 mass% or less, poor filling of the matrix resin is less likely to occur, and a decrease in selectivity can be further suppressed. The content of hydrogen storage alloy particles in the hydrogen separation membrane can be calculated from the area proportion of each component and the density of each component when a cross section of the hydrogen separation membrane is analyzed by SEM-EDX.

[0055] From the same viewpoint, the content of the hydrogen storage alloy particles in the hydrogen separation membrane is preferably 55% by mass or more and 96% by mass or less, more preferably 80% by mass or more and 96% by mass or less, and even more preferably 90% by mass or more and 96% by mass or less, based on the total amount of the hydrogen storage alloy particles and the binder resin. The content of the hydrogen storage alloy particles relative to the total amount of the hydrogen storage alloy particles and the binder resin can be calculated from the area ratio of each component and the density of each component when a cross section of the hydrogen separation membrane is analyzed by SEM-EDX.

[0056] 1-4. Other The hydrogen separation membrane may be composed of layers containing the above-mentioned components, or may further contain other layers. In particular, from the viewpoint of further increasing hydrogen permeability, it is preferable that the hydrogen separation membrane is composed of layers containing the above-mentioned components, i.e., is a single layer.

[0057] 1-5. Physical Properties 1-5-1. Hydrogen Permeability and Selectivity The hydrogen permeability measured by the differential pressure method using the apparatus described in JIS K 7126-1:2006 for hydrogen separation membranes at a measurement temperature of 80°C and a supply pressure of 1 atmosphere was 7.5 x 10 －１１ mol / m ２ The hydrogen permeability of the hydrogen separation membrane is 7.5×10 －１１ mol / m ２ From the same viewpoint, the hydrogen permeability of the hydrogen separation membrane is set to 1.0×10 s Pa or more, so that the hydrogen permeability can be sufficiently increased and the hydrogen separation membrane can function satisfactorily. －１０ mol / m ２ s Pa or more, and preferably 1.5×10 －８ mol / m ２ The upper limit of the hydrogen permeability of the hydrogen separation membrane is not particularly limited, but is, for example, 3.5×10 －６ mol / m ２ s Pa or less. That is, the hydrogen permeability of the hydrogen separation membrane can be 7.5×10 －１１ mol / m ２ ・s・Pa or more 3.5×10 －６ mol / m ２The hydrogen permeability coefficient of the hydrogen separation membrane measured by the above method can be 5.0×10 －１５ mol m / m ２ s Pa or more, and preferably 1.0 × 10 －１４ mol m / m ２ s Pa or more, and more preferably 1.2 × 10 －１２ mol m / m ２ ・s・Pa or more 2.5×10 －１０ mol m / m ２ It is more preferable that the viscosity is .s.Pa or less.

[0058] On the other hand, the carbon dioxide permeability of the hydrogen separation membrane measured by the above method is 1.5×10 －１１ mol / m ２ s Pa or less, and preferably 1.0 × 10 －１１ mol / m ２ When the carbon dioxide permeability of the hydrogen separation membrane is in the above range, the selectivity can be further improved. The lower limit of the carbon dioxide permeability of the hydrogen separation membrane is, for example, 0 mol / m ２ The carbon dioxide permeability coefficient of the hydrogen separation membrane measured by the above method can be 9.5×10 －１６ mol m / m ２ s Pa or less, and preferably 1.0 × 10 －１６ mol m / m ２ It is more preferable that the viscosity is .s.Pa or less.

[0059] Furthermore, the selectivity represented by the following formula (1) is 50 or more, as described above. When the selectivity represented by formula (1) is 50 or more, for example, a hydrogen-containing gas can be more selectively permeated from a mixed gas containing hydrogen and another gas. The selectivity is preferably 150 or more, more preferably 250 or more, even more preferably 1000 or more, and particularly preferably 10000 or more. The upper limit of the selectivity is not particularly limited, but can be, for example, 20000 or less. That is, the selectivity of the hydrogen separation membrane can be 50 or more and 20000 or less, preferably 150 or more and 20000 or less. Formula (1): Selectivity = hydrogen permeability [mol / m ２ s Pa] / carbon dioxide permeability [mol / m ２ · s · Pa]

[0060] The hydrogen permeability and selectivity of a hydrogen separation membrane can be adjusted, for example, by the content of hydrogen storage alloy particles, the content ratio of hydrogen storage alloy particles to the total amount of hydrogen storage alloy particles and binder resin, the type of binder resin, the type of matrix resin, the membrane thickness, etc. For example, increasing the content or content ratio of hydrogen storage alloy particles tends to increase both hydrogen permeability and selectivity. Furthermore, decreasing the membrane thickness tends to increase hydrogen permeability. Furthermore, if the matrix resin has high barrier properties against gases other than hydrogen gas, selectivity tends to increase.

[0061] 1-5-2. Volume resistivity The average volume resistivity at any five points of the hydrogen separation membrane at 23°C and 80% RH is, for example, 1 x 10 ９ It is preferable that the average volume resistivity is 1×10 Ω·cm or less. ９ When the resistivity is Ω cm or less, the hydrogen storage alloy particles, through which electrons can easily pass, are more closely attached to each other inside the hydrogen separation membrane, and long connected paths are more likely to be formed. Therefore, hydrogen can more selectively permeate through the corresponding paths in the hydrogen separation membrane, thereby further increasing the hydrogen permeability and selectivity. From the same perspective, the average volume resistivity of the hydrogen separation membrane is 1×10 ８ It is more preferable that the resistance is Ω cm or less, and 1×10 ７The average lower limit of the volume resistivity of the hydrogen separation membrane is, but is not particularly limited to, for example, 9×10 ５ That is, the volume resistivity of the hydrogen separation membrane can be, for example, 9×10 ５ Ω・cm or more 1×10 ９ It is possible to make it Ω·cm or less.

[0062] The volume resistivity of a hydrogen separation membrane can be measured by the following method. Specifically, a sample piece of 5 cm x 8 cm is cut from the hydrogen separation membrane. The volume resistivity of the obtained sample piece is measured at five points, namely, near the four corners and the center, using a resistivity meter (for example, a Hiresta UP MCP-HT450 manufactured by Mitsubishi Chemical Corporation, using a URS probe), and the volume resistivity can be calculated as the average value of the five points.

[0063] The volume resistivity of the hydrogen separation membrane can be adjusted by, for example, the content of hydrogen storage alloy particles and the content of binder resin. For example, increasing the content of hydrogen storage alloy particles tends to decrease the volume resistivity. Also, increasing the content of binder resin to a predetermined level or more tends to decrease the volume resistivity.

[0064] 1-5-3. Cross-sectional Area Ratio: When a field of view is taken in a range of 100 to 150 μm perpendicular to the membrane thickness direction and the center of the membrane thickness is within the membrane thickness direction, the area ratio of the elements constituting the hydrogen storage alloy particles to the total area of ​​the hydrogen separation membrane, as determined by scanning electron microscopy-energy dispersive X-ray spectroscopy, is defined as the area ratio [%] of the hydrogen storage alloy particles. When measured at five random locations in non-overlapping fields, the average area ratio of the hydrogen storage alloy particles is preferably, for example, 20% to 70%. When the area ratio is 20% or more, the content of the hydrogen storage alloy particles is greater than a predetermined level, thereby further improving hydrogen permeability and selectivity. When the area ratio is 70% or less, a decrease in selectivity due to, for example, insufficient filling of the matrix resin can be further suppressed. From the same perspective, the area ratio of the hydrogen storage alloy particles is more preferably 30% to 70%, and even more preferably 40% to 70%.

[0065] Furthermore, when the area ratio of the fluorine region to the total area of ​​the hydrogen separation membrane in the above field of view is defined as the fluororesin area ratio [%], the average area ratio of the fluororesin measured at any five locations in non-overlapping fields is preferably 10% to 65%, more preferably 10% to 40%, and even more preferably 10% to 20%. When the area ratio is 10% or more, it is easier to form a structure in which the hydrogen storage alloy particles are closely bound together, thereby further improving hydrogen permeability and selectivity. When the area ratio is 65% or less, it is possible to further suppress a decrease in hydrogen permeability and selectivity due to hindered contact between the hydrogen storage alloy particles.

[0066] Furthermore, when the area ratio of the region of the elements constituting the matrix resin to the total area of ​​the hydrogen separation membrane in the field of view is defined as the area ratio of the matrix resin [%], the average area ratio of the matrix resin measured at any five positions whose fields do not overlap each other is preferably 10% to 45% and more preferably 20% to 40%. When the area ratio is 10% or more, poor filling of the matrix resin can be further suppressed, thereby further improving selectivity. When the area ratio is 45% or less, the proportion of hydrogen storage alloy particles can be made greater than a predetermined value, thereby further improving hydrogen permeability.

[0067] The cross-sectional area ratio of each component in the cross section can be measured using a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). Specifically, the measurement can be performed using the following procedure. (Sample Preparation) The hydrogen separation membrane was cut into a 1 mm x 5 mm strip, and metallic Os was vapor-deposited to ensure electrical conductivity. The hydrogen separation membrane was then cross-sectioned using ion milling (accelerating voltage: 4 kV). (SEM-EDX Measurement) Next, a field of view was taken so that it covered a range of 100 to 150 μm in the direction perpendicular to the membrane thickness direction and the center of the membrane thickness was located in the membrane thickness direction. Next, when the field of view was analyzed using a scanning electron microscope with energy dispersive X-ray spectroscopy, regions corresponding to the hydrogen storage alloy particles, binder resin, and matrix resin were identified, and the area ratio [%] of each identified region to the total area of ​​the hydrogen separation membrane in the field of view was measured. This measurement was performed for any five locations in the field of view that did not overlap each other. The average area ratio for each region was then calculated.

[0068] The regions can be specified based on the following criteria: ４ The area where hydrogen storage alloy particles are present is determined to be the area where hydrogen storage alloy particles are present. The area where elements constituting the binder resin are detected is determined to be the area where the binder resin is present. For example, if the binder resin is a fluorine-based resin, the area where fluorine is detected is determined to be the area where the fluorine-based resin is present. The area where elements constituting the matrix resin are detected is determined to be the area where the matrix resin is present. For example, if the matrix resin contains a cured product of a thermosetting resin composition containing an epoxy resin and an amine curing agent, the area where nitrogen derived from the amine curing agent or oxygen derived from the epoxy resin is present can be determined to be the area where the matrix resin is present.

[0069] When the binder resin is a resin other than a fluorine-based resin, the region where the binder resin is present can also be identified by the following method. When the constituent elements of the binder resin are the same as those of the matrix resin (for example, PEO and epoxy resin), the boundary can be identified by the density of the common element (for example, oxygen). On the other hand, when the constituent elements of the binder resin are not the same as those of the matrix resin (for example, SBR and epoxy resin), the region where carbon is detected among the regions other than the region where the hydrogen storage alloy particles are present and the region where the matrix resin is present can be determined to be the binder resin region.

[0070] 1-5-4. Thickness The thickness of the hydrogen separation membrane is not particularly limited, but is preferably thin from the viewpoint of further increasing hydrogen permeability. For example, the thickness of the hydrogen separation membrane is preferably 120 μm or less, and more preferably 100 μm or less. The lower limit of the thickness of the hydrogen separation membrane is not particularly limited, but can be, for example, 15 μm or more. That is, the thickness of the hydrogen separation membrane can be, for example, 15 μm or more and 120 μm or less.

[0071] The thickness of the hydrogen separation membrane can be determined by measuring the membrane thickness at five arbitrarily selected points using an indicator (ID-S112PX2, manufactured by Mitutoyo) and calculating the average value.

[0072] 1-5-5. Density The density of the hydrogen separation membrane is not particularly limited, but is preferably 2.5 g / cm ３ It is preferable that the density is 3.0 g / cm or more. ３ More preferably, it is 3.5 g / cm or more. ３ It is more preferable that the density of the hydrogen separation membrane is 2.5 g / cm or more. ３ When the density is 4.2 g / cm or more, the hydrogen permeability can be further increased due to the high content of hydrogen storage alloy particles. ３ That is, the density of the hydrogen separation membrane can be, for example, 2.5 g / cm ３ 4.2g / cm or more ３ Preferably 3.0 g / cm or less ３ 4.2g / cm or more ３It can be as follows:

[0073] The density of a hydrogen separation membrane can be measured by the following procedure. A hydrogen separation membrane is punched out with a circular punch having a diameter of 14 mm to obtain a sample piece. The weight of the obtained sample piece is measured using an analytical balance (Shimadzu Corporation, AP224X). The volume is then calculated from the area of ​​the sample piece and the membrane thickness, and the weight is divided by the volume to calculate the density. This measurement is performed three times, and the average value of the three measurements is taken as the density.

[0074] The density of the hydrogen separation membrane can be adjusted mainly by the content of hydrogen storage alloy particles. For example, the density tends to increase as the content of hydrogen storage alloy particles in the hydrogen separation membrane increases.

[0075] 2. Method for Manufacturing Hydrogen Separation Membrane FIGS. 2A and 2B are schematic cross-sectional views showing a method for manufacturing the hydrogen separation membrane 10. As shown in FIG.

[0076] The hydrogen separation membrane can be manufactured by any method. In this embodiment, the hydrogen separation membrane 10 can be manufactured through a step of manufacturing a porous membrane 10A containing hydrogen storage alloy particles 12 and a binder resin 11B (porous membrane manufacturing step), and a step of filling voids 13 of the porous membrane 10A with a matrix resin 11A (resin filling step).

[0077] 2-1. Porous Membrane Fabrication Step First, a porous membrane containing hydrogen storage alloy particles and a binder resin is fabricated (see FIG. 2A).

[0078] The porous membrane can be produced by any method. For example, a method of molding hydrogen storage alloy particles and a binder resin by pressing or the like, or a method of applying a slurry containing hydrogen storage alloy particles, a binder resin, and a solvent can be used. Among these, the method of applying a slurry containing hydrogen storage alloy particles, a binder resin, and a solvent is preferred from the viewpoint of easily forming a thin porous membrane.

[0079] The slurry may be prepared by simultaneously mixing the hydrogen storage alloy particles, the binder resin, and the solvent, or by mixing the binder resin and the solvent and then adding the hydrogen storage alloy particles and mixing them together. In particular, from the viewpoint of making it easier to bind the hydrogen storage alloy particles with the binder resin, it is preferable to mix the binder resin and the solvent together and then add and mix the hydrogen storage alloy particles to prepare a slurry.

[0080] That is, it is preferable to prepare a porous membrane through the steps of: 1) obtaining a solution (binder solution) containing a binder resin and a solvent capable of dispersing or dissolving the binder resin; and 2) mixing the obtained binder solution with hydrogen storage alloy particles, followed by molding and drying.

[0081] The solvent used to prepare the binder solution is not particularly limited as long as it can disperse or dissolve the binder resin, and water or an organic solvent such as acetone, ethanol, or N-methyl-2-pyrrolidone (NMP) can be used.

[0082] Methods for forming the mixture (slurry) of the binder solution and hydrogen storage alloy particles include known methods such as spraying, screen printing, gravure printing, die coating, doctor blade, and ink jet printing.

[0083] The drying temperature may be any temperature that can volatilize and remove the solvent in the slurry to some extent, and may be, for example, 80°C or higher and 110°C or lower.

[0084] 2-2. Resin Filling Step Next, the voids in the obtained porous film are filled with a matrix resin (see FIG. 2B).

[0085] For example, when the matrix resin contains a cured product of a thermosetting resin composition, the matrix resin can be filled by impregnating the voids of the porous membrane with the thermosetting resin composition and then thermally curing it. The impregnation method is not particularly limited, and may be a method of immersing the porous membrane in the thermosetting resin composition, or a method of applying the thermosetting resin composition to the surface of the porous membrane. Furthermore, the thermosetting resin composition may be impregnated under an atmosphere other than the air atmosphere, such as a vacuum atmosphere, or may be impregnated under any conditions in which the temperature and pressure are adjusted using a hot press or roll press. This allows the voids of the porous membrane to be filled with the cured product of the thermosetting resin composition.

[0086] The heat curing temperature is not particularly limited as long as it is a temperature at which the thermosetting resin composition cures, but it is preferably lower than the glass transition temperature of the binder resin. For example, the heat curing temperature is preferably 50° C. or higher and 200° C. or lower.

[0087] The hydrogen separation membrane described above has excellent hydrogen permeability and selectivity, and therefore can be preferably used for separating or recovering a hydrogen-containing gas from a mixed gas containing hydrogen and a gas other than hydrogen (e.g., carbon dioxide, oxygen, nitrogen, etc.).

[0088] 4. Method for Producing Hydrogen Gas The hydrogen separation membrane described above can be applied to, for example, a method for producing hydrogen gas.

[0089] That is, the method for producing hydrogen gas according to this embodiment includes a step of supplying a mixed gas containing hydrogen and a gas other than hydrogen to a space in contact with one side of a hydrogen separation membrane, and a step of recovering a gas containing hydrogen from the space in contact with the other side of the hydrogen separation membrane.

[0090] The type of gas other than hydrogen is not particularly limited, but examples include at least one gas selected from carbon dioxide, oxygen, nitrogen, and methane.

[0091] The supply pressure of the mixed gas is not particularly limited, but can be, for example, 0.1 MPa or more and 10 MPa or less. By setting the gas supply pressure to 0.1 MPa or more, the gas permeation rate increases, and by setting it to 10 MPa or less, deformation of the hydrogen separation membrane due to pressure can be further suppressed.

[0092] The supply temperature of the mixed gas may be set depending on the application of the hydrogen gas, and is not particularly limited, but may be, for example, 80° C. or higher and 100° C. or lower. By setting the supply temperature of the mixed gas within the above range, the recovered hydrogen-containing gas can be preferably used, for example, as fuel for a fuel cell.

[0093] According to the above-described manufacturing method, by using the above-described hydrogen separation membrane, it is possible to efficiently separate and recover a hydrogen-containing gas from a mixed gas containing hydrogen and a gas other than hydrogen, i.e., it is possible to recover a gas having a higher hydrogen / gas other than hydrogen molar ratio than the supplied mixed gas.

[0094] The obtained hydrogen gas can be used for various purposes, for example, as a fuel for fuel cells, hydrogen engines, etc.

[0095] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0096] 1. Preparation of materials 1-1. Hydrogen storage alloy particles LaNi ４ Al (manufactured by Kojundo Chemical Laboratory Co., Ltd., average particle diameter 10.2 μm). The average particle diameter is the particle diameter (median diameter (D50)) at an integrated value of 50% in the volume distribution, measured using a Microtrac particle size distribution measuring device MT3300EXII (manufactured by Microtrac Bell).

[0097] 1-2. Binder resin PVDF: Polyvinylidene fluoride (KF#850, manufactured by Kureha) SBR: Styrene butadiene rubber dispersion (solid content concentration 40% by mass) PEO: Polyethylene oxide (manufactured by Sigma-Aldrich)

[0098] 1-3. Matrix resin material (thermosetting resin) Epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxive (registered trademark), M-100, an epoxy compound having four epoxy groups in one molecule and a glycidylamine moiety)

[0099] (Curing agent) Polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93, polyamine resin)

[0100] The glass transition temperature (Tg) of the cured product of a mixture of Maxieve (registered trademark) M-100 and Maxieve (registered trademark) C-93 mixed at a mass ratio of 5:16 is 108°C. The glass transition temperature (Tg) is a value measured in accordance with JIS K 7121:2012 using a differential scanning calorimeter (e.g., DSC1 manufactured by Mettler Toledo) at a temperature rise rate of 20°C / min. The carbon dioxide permeability coefficient (80°C, differential pressure of 1 atmosphere) of the cured product measured by the differential pressure method in accordance with JIS K 7126-1:2006 is 1.5 x 10 －１７ (mol m / m ２ .s.Pa).

[0101] 2. Sample Preparation [Preparation of Sample 1] (Slurry Preparation) PVDF (KF#850, manufactured by Kureha) was added to N-methyl-2-pyrrolidone (NMP, manufactured by Nippon Refine Co., Ltd.) to a concentration of 20% by mass, and dissolved at 50°C to obtain a binder resin solution. Next, the PVDF and hydrogen storage alloy particles LaNi ４ The mass ratio of PVDF to Al is PVDF:LaNi ４ The binder resin solution was mixed with LaNi and Al in a ratio of 80:20. ４ Al was added and the mixture was kneaded with a thinking mixer (AER-300, manufactured by Shinki) at 2000 rpm for 2 minutes to prepare a slurry.

[0102] (Preparation of porous membrane) The obtained slurry was applied to a PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 100 μm) using an applicator. ２ The mixture was subjected to a heat treatment at 110° C. for 30 minutes in an atmosphere to evaporate the NMP, thereby obtaining a porous film.

[0103] (Filling with matrix resin) An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) were mixed in a mass ratio of 5:16 to prepare a thermosetting resin composition for the matrix resin. Next, one side of the prepared porous membrane was coated with and impregnated with the resin composition using a bar coater (AS ONE Corporation, non-wire bar coater φ10 × 250 mm, count #3), and the mixture was heat-treated in the incubator at 80°C for 30 minutes to be thermally cured, thereby filling the matrix resin and obtaining Sample 1.

[0104] [Preparation of Samples 2 to 7] PVDF and hydrogen storage alloy particles LaNi ４ Samples 2 to 7 were obtained in the same manner as Sample 1, except that the mass ratio with Al was changed as shown in Table 1.

[0105] [Preparation of Sample 8] (Preparation of porous film) PVDF and hydrogen storage alloy particles LaNi ４ The mass ratio of PVDF to Al is PVDF:LaNi ４ A porous film was obtained in the same manner as in Sample 1, except that the Al ratio was changed to 0.5:99.5.

[0106] (Filling with matrix resin) An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) were mixed in a mass ratio of 5:16 to prepare a matrix resin-forming composition. Then, when an attempt was made to coat and impregnate the surface of the porous membrane prepared above with the thermosetting resin composition, the porous membrane was torn and coating was not possible.

[0107] [Preparation of Sample 9] (Preparation of Slurry) An SBR dispersion (solid content concentration: 40% by mass) was prepared as a binder resin dispersion. ４ Al and sodium carboxymethyl cellulose (CMC) as a thickener, ４ The components were mixed in a mass ratio of Al:CMC = 3:97:1, and the mixture was kneaded with a THINKY MIXER (AER-300, manufactured by Shinki Co., Ltd.) at 2000 rpm for 2 minutes to obtain a slurry.

[0108] (Preparation of porous membrane) The obtained slurry was applied to a PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 100 μm) using an applicator. ２ The film was dried by heat treatment at 80° C. for 30 minutes in an atmosphere to obtain a porous film.

[0109] (Filling with matrix resin) An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) were mixed in a mass ratio of 5:16 to prepare a thermosetting resin composition for the matrix resin. Next, the surface of the porous membrane prepared above was coated and impregnated with the thermosetting resin composition using a bar coater (AS ONE Corporation, non-wire bar coater φ10 × 250 mm, count #3), and the mixture was heat-treated in the incubator at 80°C for 30 minutes to be thermally cured, thereby filling the matrix resin and obtaining Sample 9.

[0110] [Preparation of Sample 10] (Preparation of Slurry) Polyethylene oxide (PEO, manufactured by Sigma-Aldrich) was added to ion-exchanged water and dissolved therein to a concentration of 10% by mass to obtain a binder resin solution. Next, PEO and hydrogen storage alloy particles LaNi ４ The mass ratio of PEO to Al is PEO:LaNi ４ The binder resin solution was mixed with LaNi and Al in a ratio of 20:80. ４ Al was added and the mixture was kneaded with a thinking mixer (AER-300, manufactured by Shinki) at 2000 rpm for 2 minutes to obtain a slurry.

[0111] (Preparation of porous membrane) The obtained slurry was applied to a PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 100 μm) using an applicator. ２ The film was dried by heat treatment at 80° C. for 30 minutes in an atmosphere to obtain a porous film.

[0112] (Filling with matrix resin) An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) were mixed at a mass ratio of 5:16 to prepare a thermosetting resin composition for the matrix resin. Next, the surface of the porous membrane prepared above was coated with and impregnated with the thermosetting resin composition using a bar coater (non-wire bar coater φ10 × 250 mm, count #3, manufactured by AS ONE Corporation), and the mixture was heat-treated in the incubator at 80°C for 30 minutes to be thermally cured, thereby filling the matrix resin and obtaining Sample 10.

[0113] [Preparation of Sample 11] An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxive (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxive (registered trademark), C-93) were mixed in a mass ratio of 5:16 to prepare a thermosetting resin composition for the matrix resin. This thermosetting resin composition and LaNi ４ Al in a thermosetting resin composition: LaNi ４ The mixture was mixed so that the mass ratio of Al was 60:40. Next, the mixture was applied to a Teflon sheet (Naflon (registered trademark), manufactured by Nichias Corporation, thickness 50 μm) using a bar coater (non-wire bar coater φ10 × 250 mm, count #20, manufactured by AS ONE Corporation). After that, the mixture was heat-treated at 80 ° C. for 30 minutes in an incubator (HT220S, manufactured by Kusumoto Chemicals Co., Ltd.) to prepare Sample 11.

[0114] [Preparation of Samples 12 and 13] Hydrogen storage alloy particles LaNi ４ Samples 12 and 13 were prepared in the same manner as Sample 11, except that the mass ratio of Al to the thermosetting resin composition for the matrix resin was changed as shown in Table 1.

[0115] [Preparation of Sample 14] A mixture of epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) was further coated on the surface of Sample 13 using a bar coater (non-wire bar coater φ10×250 mm, count #3, manufactured by AS ONE Corporation), and the coated surface was subjected to heat treatment at 80° C. for 30 minutes in an incubator (Kusumoto Chemicals Co., Ltd., HT220S) to obtain Sample 14.

[0116] [Preparation of Sample 15] An epoxy resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), M-100) and a polyamine resin (Mitsubishi Gas Chemical Company, Inc., Maxieve (registered trademark), C-93) were mixed in a mass ratio of 5:16 to prepare a thermosetting resin composition for the matrix resin. The thermosetting resin composition was applied to a Teflon sheet (Nachias Corporation, Naflon (registered trademark), 50 μm thick) using a bar coater (AS ONE Corporation, non-wire bar coater, φ10 × 250 mm, grit #12). The sheet was then heat-treated at 80°C for 30 minutes in an incubator (Kusumoto Chemicals Co., Ltd., HT220S) to obtain a matrix resin film (Sample 15).

[0117] 3. Evaluation The following measurements were carried out on each of the samples 1 to 15 prepared above.

[0118] 3-1. Film Formability When the sample having a size of 148 mm x 210 mm prepared above could be maintained as a film, it was marked with a circle, and when it was impossible to maintain as a film and the film could not be evaluated, it was marked with an X.

[0119] 3-2. Film Thickness The film thickness of five randomly selected points on the prepared sample was measured using an indicator (ID-S112PX2, manufactured by Mitutoyo), and the average value was taken as the film thickness.

[0120] 3-3. Density The prepared samples were punched out with a circular punch having a diameter of 14 mm to obtain sample pieces. The weight of the obtained sample pieces was measured using an analytical balance (Shimadzu Corporation, AP224X). The film thickness of the sample pieces was also measured in the same manner as in 3-2. The volume was then calculated from the area and film thickness of the sample pieces, and the weight was divided by the volume to calculate the density. The above measurement was performed three times for each sample, and the average value of the three measurements was taken as the density.

[0121] 3-4. Fluorine content The fluorine content relative to the total mass of the sample was measured for three randomly selected points by combustion ion chromatography, and the average value was taken as the fluorine content. The measurement conditions were as follows: [Automatic sample combustion device] Device: AQF-2100H (manufactured by Nitto Seiko Analytech Co., Ltd.) (electric furnace unit) Decomposition temperature: Inlet: 900°C, Outlet: 1000°C Ar flow rate: 200 mL / min O２ Flow rate: 400 mL / min (gas absorption unit) Absorption solution composition: 10 ml of ultrapure water [Ion chromatograph] Apparatus: IC-2010 (manufactured by Tosoh Corporation) Separation column: TSKgel Super IC-Anion HS (4.6 mm ID x 100 mm) Eluent: 9.0 mM NaHCO ３ +1.0 mM Na ２ CO ３ Flow rate: 1.0 mL / min Column temperature: 40°C

[0122] The prepared sample was cut into a size of 5 cm x 8 cm. The volume resistivity of the obtained sample was measured at five points, namely near the four corners and at the center, using a Mitsubishi Chemical Hiresta UP MCP-HT450 and URS probe at 23°C and 80% RH, and the average value of the five points was recorded as the volume resistivity.

[0123] 3-6. Cross-sectional area ratio The cross-sectional area ratio of each component in the cross section was evaluated by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX).

[0124] (Preparation of Sample Pieces) The samples were cut into strips of 1 mm x 5 mm, and metal Os was vapor-deposited on them to ensure electrical conductivity. Then, the cross sections of the samples were cut out by ion milling (acceleration voltage 4 kV).

[0125] (SEM-EDX Measurement) A field of view was taken for the obtained sample piece so that it covered a range of 100 to 150 μm in the direction perpendicular to the film thickness direction and so that the center of the film thickness of the sample piece was located in the film thickness direction. Next, when the field of view was analyzed by scanning electron microscope-energy dispersive X-ray spectroscopy, regions corresponding to the hydrogen storage alloy particles, binder resin, and matrix resin were identified, and the area ratio of each region to the total area of ​​the sample piece in the field of view was measured as area ratio [%].

[0126] Each region was identified as follows: For samples 1 to 8 and 11 to 14, the area where Ni was detected was identified as a region where hydrogen storage alloy particles existed, the area where fluorine was detected as a region where fluorine-based resin existed, and the area where only carbon was detected as a region where epoxy resin existed. For sample 9, the area where Ni was detected was identified as a region where hydrogen storage alloy particles existed, the area where nitrogen was detected as a region where thermosetting resin existed (because polyamine resin was used as a curing agent), and the area where only carbon was detected but no nitrogen was detected as a region where SBR existed. For sample 10, the area where Ni was detected was identified as a region where hydrogen storage alloy particles existed, and the boundary and area between PEO and epoxy resin were identified by the shading due to the difference in carbon and oxygen concentrations.

[0127] This measurement was carried out at any five locations whose visual fields did not overlap each other, and the average value was calculated.

[0128] 3-7. Gas permeability and selective gas permeability [mol / m ２ The pressure drop was measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006. The apparatuses used were GTR-21A-A, GTR-21A-B, and GTR-30XA manufactured by GTR Tech Co., Ltd. The measurement temperature was 80°C, and the supply pressure was 0.1 MPa (differential pressure 0.1 MPa). The selectivity was calculated by applying the hydrogen permeability and carbon dioxide permeability to the following formula (1): Formula (1): Selectivity = hydrogen permeability [mol / m ２ s Pa] / carbon dioxide permeability [mol / m ２ · s · Pa]

[0129] The compositions of Samples 1 to 15 are shown in Table 1, and the evaluation results are shown in Table 2. Regarding the charge compositions in Table 1, for Samples 1 to 10, the mass ratio of each component to the total mass of the hydrogen storage alloy particles and binder resin is shown. For Samples 11 to 16, the mass ratio of each component to the total mass of the hydrogen storage alloy particles and matrix resin is shown. The film compositions calculated from the cross-sectional images of the films in Table 1 represent the mass ratio of each component to the entire film, calculated from the area ratio and density of each component in the SEM-EDX analysis image (cross-sectional image). Figures 3A to 3C are monochrome processed SEM-EDX analysis images of the cross sections of the samples. Specifically, the SEM-EDX analysis images have been decolorized from the areas where only carbon is detected (areas where the matrix resin is present). Of these, Figure 3A is a processed image of Sample 5, Figure 3B is Sample 13, and Figure 3C is Sample 14.

[0130]

[0131]

[0132] As shown in Table 2, the thermosetting resin composition for the matrix resin and LaNi ４ Among samples 11 to 14 obtained by mixing LaNi and Al and then coating, samples 11 and 12 contain LaNi. ４ Compared with sample 15, which does not contain Al, the selectivity was slightly improved, but it was not sufficient. This is because, as shown in Figure 3B, ４ This is thought to be because Al is dispersed in the film, and almost no paths for hydrogen permeation are formed. In addition, when the amount of hydrogen storage alloy particles is increased compared to samples 11 and 12, as in sample 13, the hydrogen permeability is slightly higher, but the selectivity is reduced. This is because, as shown in Figure 3B, the thermosetting resin composition for the matrix resin and LaNi ４ This is thought to be because Al alone is prone to trapping air bubbles. Furthermore, in Sample 14, in which the surface of Sample 13 was further coated with epoxy resin to seal the pores, the selectivity was almost unchanged compared to before coating (see Figure 3C).

[0133] In contrast, the binder resin and LaNi ４After forming a porous film containing LaNi and Al, the voids were filled with a matrix resin. ４ As the Al content ratio increases, the volume resistivity decreases and the cross-sectional area ratio of the hydrogen storage alloy particles increases, which tends to increase the hydrogen permeability and selectivity. ４ In samples 3 to 6, 9 and 10 in which the Al content ratio was set to a predetermined value or more, the hydrogen permeability was 7.5 × 10 －１１ mol / m ２ s Pa or more, and the selectivity was also high at 50 or more. This is because, as shown in Figure 3A, ４ Al is well bound by the binder resin, ４ This is thought to be because a path connecting Al was formed.

[0134] This application claims priority based on Japanese Patent Application Nos. 2024-147540, 2024-147547, and 2024-147550, filed on August 29, 2024. The contents of the specifications and drawings of these applications are incorporated herein by reference in their entirety.

[0135] According to the present invention, it is possible to provide a hydrogen separation membrane that achieves both high hydrogen permeability and high selectivity.

[0136] REFERENCE SIGNS LIST 10 Hydrogen separation membrane 10A Porous membrane 11 Resin 11A Matrix resin 11B Binder resin 12 Hydrogen storage alloy particles 13 Void

Claims

1. A hydrogen separation membrane containing a resin and hydrogen storage alloy particles, which has a hydrogen permeability of 7.5 x 10 measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere. －１１ mol / m ２ A hydrogen separation membrane having a selectivity of 50 or more, expressed as the ratio of the hydrogen permeability to the carbon dioxide permeability measured by a differential pressure method using an apparatus described in JIS K 7126-1:2006 at a measurement temperature of 80°C and a supply pressure of 1 atmosphere, as shown in the following formula (1): Selectivity = hydrogen permeability [mol / m ２ s Pa] / carbon dioxide permeability [mol / m ２ · s · Pa] 2. The hydrogen separation membrane according to claim 1, wherein the selectivity is 150 or more.

3. The average volume resistivity of the hydrogen separation membrane at any five points under 23°C and 80% RH is 1 x 10 ９ The hydrogen separation membrane according to claim 1 , having a resistivity of Ω·cm or less.

4. The hydrogen separation membrane according to claim 1, wherein, when a field of view is taken in a range of 100 to 150 μm in a direction perpendicular to the membrane thickness direction and the center of the membrane thickness is within the membrane thickness direction in a cross section of the hydrogen separation membrane, the average area ratio of the hydrogen storage alloy particles [%] is 20% or more and 70% or less when measured at any five positions in non-overlapping fields of view, and the area ratio of the hydrogen storage alloy particles in the field of view is taken as the area ratio of the hydrogen storage alloy particles [%] relative to the total area of ​​the hydrogen separation membrane.

5. The hydrogen separation membrane according to claim 1, wherein the resin contains a binder resin that binds the hydrogen storage alloy particles, and the binder resin contains at least one resin selected from the group consisting of fluorine-based resins, diene-based rubbers, polyethylene oxide (PEO), polyolefin resins, urethane resins, phenolic resins, polyethers, polyamides, polyesters, vinyl resins, and acrylic acid-based copolymers.

6. The hydrogen separation membrane according to claim 1, wherein the resin comprises a fluorine-based resin.

7. The hydrogen separation membrane according to claim 6, wherein the fluorine content measured by combustion ion chromatography is 3 mass % or more and 40 mass % or less based on the total mass of the hydrogen separation membrane.

8. The hydrogen separation membrane according to claim 6, wherein, in a cross section of the hydrogen separation membrane, a field of view is taken so as to fall within a range of 100 to 150 μm in a direction perpendicular to the membrane thickness direction and so as to include the center of the membrane thickness in the membrane thickness direction, and when the area ratio of the fluorine region in the field of view obtained by scanning electron microscope-energy dispersive X-ray spectroscopy to the total area of ​​the hydrogen separation membrane in the field of view is taken as the area ratio [%] of the fluororesin, the average area ratio of the fluororesin when measured at any five positions in the field of view that do not overlap each other is 10% or more and 65% or less.

9. The hydrogen separation membrane according to any one of claims 1 to 8, wherein the resin comprises a cured product of a curable resin composition containing a curable resin.

10. The hydrogen separation membrane according to claim 9, wherein the cured product has a glass transition temperature of 80°C or higher.

11. The density of the hydrogen separation membrane is 2.5 g / cm ３ The hydrogen separation membrane according to any one of claims 1 to 10, wherein 12. The hydrogen separation membrane according to any one of claims 1 to 11, having a membrane thickness of 120 µm or less.

13. A method for producing a hydrogen separation membrane according to any one of claims 1 to 12, comprising the steps of: preparing a porous membrane containing hydrogen storage alloy particles and a binder resin that binds the hydrogen storage alloy particles; and filling voids in the porous membrane with a curable resin composition containing a curable resin, and curing the composition.

14. The method for producing a hydrogen separation membrane according to claim 13, wherein the step of producing the porous membrane comprises the steps of: obtaining a solution containing the binder resin and a solvent capable of dispersing or dissolving the binder resin; and mixing the solution with the hydrogen storage alloy particles, followed by molding and drying to obtain the porous membrane.

15. The method for producing a hydrogen separation membrane according to claim 13 or 14, wherein the binder resin contains at least one resin selected from the group consisting of fluorine-based resins, diene-based rubbers, polyethylene oxide (PEO), polyolefin resins, urethane resins, phenolic resins, polyethers, polyamides, polyesters, vinyl resins, and acrylic acid-based copolymers.

16. A method for producing hydrogen gas, comprising the steps of: supplying a mixed gas containing hydrogen and a gas other than hydrogen to a space in contact with one side of the hydrogen separation membrane described in any one of claims 1 to 12; and recovering a gas containing hydrogen from the space in contact with the other side of the hydrogen separation membrane.

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