Separation membrane

Abstract

The present invention provides a novel separation membrane suitable for separating hydrogen from a hydrogen-containing gas mixture. The separation membrane 10 of the present invention comprises a separation functional layer 1 and a protective layer 5 that protects the separation functional layer 1. The ratio A2 / A1 of the thickness of the protective layer 5 to the thickness A1 (μm) of the separation functional layer 1 is 0.5 or more and less than 2.0.

Description

[Technical Field]

[0001] This invention relates to a separation membrane. [Background technology]

[0002] In recent years, technologies utilizing hydrogen as an energy source have been developed from the perspective of reducing environmental impact. Consequently, methods for purifying hydrogen are also being investigated. In particular, steam reforming, which involves reacting hydrocarbons such as methane with water vapor, yields a mixed gas containing not only hydrogen but also the hydrocarbon raw materials. There is a need for efficient methods to separate hydrogen from such mixed gases.

[0003] One possible method for separating hydrogen from a hydrogen-containing gas mixture is membrane separation. Membrane separation has the potential to efficiently separate hydrogen from a gas mixture while keeping operating costs down. Patent Document 1 discloses a composite membrane used in the above-mentioned membrane separation method, in which a cross-linked polyamide separation functional layer is formed on a support membrane. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-54573 [Overview of the project] [Problems that the invention aims to solve]

[0005] There is a need for new separation membranes suitable for separating hydrogen from a mixture of gases containing hydrogen. [Means for solving the problem]

[0006] The present invention Separation functional layer, A protective layer that protects the separation functional layer, Equipped with, The present invention provides a separation membrane in which the ratio A2 / A1 of the thickness of the protective layer to the thickness A1 (μm) of the separation functional layer is 0.5 or more and less than 2.0. [Effects of the Invention]

[0007] According to the present invention, a novel separation membrane suitable for separating hydrogen from a hydrogen-containing gas mixture can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing a separation membrane according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of a membrane separation apparatus equipped with the separation membrane of the present invention. [Figure 3] This is a schematic perspective view showing a modified example of a membrane separation apparatus equipped with the separation membrane of the present invention. [Figure 4] This graph shows the results of pressure resistance test 1 for the separation membranes in Examples 9-11. [Figure 5] This graph shows the results of pressure resistance test 1 for the separation membranes in Examples 12-14. [Figure 6] This graph shows the results of pressure resistance test 2 for the separation membranes in Examples 9-11. [Figure 7] This graph shows the results of pressure resistance test 2 for the separation membranes in Examples 12-14. [Modes for carrying out the invention]

[0009] A separation membrane according to a first aspect of the present invention is Separation functional layer, A protective layer that protects the separation functional layer, Equipped with, The ratio A2 / A1 of the thickness of the protective layer to the thickness A1 (μm) of the separation functional layer is 0.5 or more and less than 2.0.

[0010] In a second embodiment of the present invention, for example, in the separation membrane according to the first embodiment, the thickness A1 is 0.01 μm to 50 μm.

[0011] In a third aspect of the present invention, for example, in the separation membrane according to the first or second aspect, the thickness A2 is 0.01 μm to 50 μm.

[0012] In a fourth embodiment of the present invention, for example, in a separation membrane according to any one of the first to third embodiments, the separation functional layer includes at least one selected from the group consisting of polyamide, cellulose ester, polyolefin, fluorine-containing polymer, polysulfone, and ceramic.

[0013] In a fifth embodiment of the present invention, for example, in a separation membrane according to any one of the first to fourth embodiments, the protective layer includes a silicone resin.

[0014] In a sixth aspect of the present invention, for example, in a separation membrane according to any one of the first to fifth aspects, the protective layer is formed from an addition-type silicone resin composition or a condensation-type silicone resin composition.

[0015] In a seventh embodiment of the present invention, for example, in a separation membrane according to any one of the first to sixth embodiments, the protective layer is in direct contact with the separation functional layer.

[0016] In the eighth aspect of the present invention, for example, the separation membrane according to any one of the first to seventh aspects further comprises a porous support that supports the separation functional layer.

[0017] In the ninth aspect of the present invention, for example, in a separation membrane according to any one of the first to eighth aspects, when helium at a pressure of 0.6 MPa is supplied to a space adjacent to one side of the separation membrane, the helium permeation rate T through the separation membrane is He The number of GPUs is 100 or more.

[0018] In the tenth embodiment of the present invention, for example, in a separation membrane according to any one of the first to ninth embodiments, the separation coefficient of helium relative to nitrogen is α He / N2 The number is 200 or more. Here, the separation coefficient αHe / N2 refers to the permeation rate T of nitrogen that permeates through the separation membrane when nitrogen at a pressure of 0.6 MPa is supplied to the space adjacent to one surface of the separation membrane. N2 refers to the permeation rate T of helium that permeates through the separation membrane when helium at a pressure of 0.6 MPa is supplied to the space (GPU) He The ratio T of (GPU) He / T N2 is meant.

[0019] In the 11th aspect of the present invention, for example, in the separation membrane according to any one of the 1st to 10th aspects, the separation factor α of helium with respect to carbon dioxide He / CO2 is 20 or more. Here, the separation factor α He / CO2 refers to the permeation rate T of carbon dioxide that permeates through the separation membrane when carbon dioxide at a pressure of 0.6 MPa is supplied to the space adjacent to one surface of the separation membrane. CO2 refers to the permeation rate T of helium that permeates through the separation membrane when helium at a pressure of 0.6 MPa is supplied to the space (GPU) He The ratio T of (GPU) He / T CO2 is meant.

[0020] In the 12th aspect of the present invention, for example, the separation membrane according to any one of the 1st to 11th aspects is used for separating hydrogen from a mixed gas containing hydrogen.

[0021] Hereinafter, the details of the present invention will be described, but the following description is not intended to limit the present invention to specific embodiments.

[0022] <Embodiment of the separation membrane> As shown in FIG. 1, the separation membrane 10 of the present embodiment includes a separation functional layer 1 and a protective layer 5 that protects the separation functional layer 1. The protective layer 5 is preferably in direct contact with the separation functional layer 1. In this case, the separation functional layer 1 easily allows small-sized molecules such as hydrogen and helium to preferentially permeate. In the separation membrane 10, the ratio A2 / A1 of the thickness A2 (μm) of the protective layer 5 to the thickness A1 (μm) of the separation functional layer 1 is 0.5 or more and less than 2.0.

[0023] According to the inventors' studies, in a separation membrane 10 with a ratio A2 / A1 of 0.5 or higher, defects such as cracks in the separation functional layer 1 are sufficiently filled by the protective layer 5, and the decrease in separation performance due to defects tends to be sufficiently suppressed. The ratio A2 / A1 is preferably 0.6 or higher, 0.7 or higher, 0.8 or higher, 0.9 or higher, 1.0 or higher, 1.1 or higher, 1.2 or higher, 1.3 or higher, and may even be 1.4 or higher.

[0024] Furthermore, according to the inventors' studies, in separation membranes 10 where the ratio A2 / A1 is less than 2.0, the decrease in permeability to small molecules such as hydrogen and helium caused by the protective layer 5 tends to be sufficiently suppressed. The ratio A2 / A1 is preferably 1.9 or less, and may be 1.8 or less, 1.7 or less, 1.6 or less, and even 1.5 or less. In some cases, the ratio A2 / A1 may be 1.4 or less, and may be 1.3 or less, 1.2 or less, 1.1 or less, 1.0 or less, and even 0.9 or less. A ratio A2 / A1 of 0.5 to 1.5 is particularly preferred.

[0025] The thickness A1 of the separation functional layer 1 can be determined by the following method. First, the cross-section of the separation membrane 10 is observed at any multiple points (at least 3 points) using a transmission electron microscope (TEM). The magnification at this time is, for example, 20,000 times. Next, for each of the obtained TEM images, the minimum value a1 (μm) and maximum value a2 (μm) of the thickness of the separation functional layer 1 are determined. The minimum value a1 and maximum value a2 of the thickness of the separation functional layer 1 refer to the minimum and maximum distances between a pair of opposing main surfaces of the separation functional layer 1 in the stacking direction of the separation functional layer 1 and the protective layer 5, respectively. In this specification, the main surface refers to the surface of the separation functional layer 1 that has the largest area.

[0026] As described later, the separation functional layer 1 may have a pleated microstructure, and these pleats may penetrate into the interior of the protective layer 5. In this case, the region where the pleats exist is also considered part of the separation functional layer 1, and the minimum value a1 and maximum value a2 of the thickness of the separation functional layer 1 are determined.

[0027] Next, the average value a1 of the minimum value a1 identified from each TEM image. ave (μm) and the average value a2 of the maximum value a2 identified from each TEM image. ave Calculate (μm). Average value a1 ave and a2 ave Based on this, the formula is: (mean value a1 ave (μm)+average value a2 ave The value calculated by (μm) / 2 can be considered as the thickness A1 of the separation functional layer 1.

[0028] The thickness A1 of the separation functional layer 1 is, for example, 50 μm or less, and may be 25 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, and even 0.5 μm or less. The smaller the thickness A1 of the separation functional layer 1, the more likely it is that the permeation rate of the permeating fluid passing through the separation membrane 10 will improve. The lower limit of the thickness A1 of the separation functional layer 1 is, for example, 0.01 μm or more, and may be 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, 0.1 μm or more, and even 0.3 μm or more. The thickness A1 of the separation functional layer 1 is preferably 0.01 μm to 50 μm.

[0029] Furthermore, if the separation functional layer 1 has a pleated microstructure, the pleat height A3 is not particularly limited and may be, for example, 50 μm or less, 25 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, or even 0.5 μm or less. The lower limit of the pleat height A3 is, for example, 0.01 μm or more, but may be 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, 0.1 μm or more, or even 0.3 μm or more. The ratio A2 / A3 of the thickness A2 (μm) of the protective layer 5 to the pleat height A3 (μm) may be 0.40 to 1.00, or 0.45 to 0.95.

[0030] The height A3 of the folds in the separation functional layer 1 can be determined by the following method. First, the average value a1 is determined by the method described above. ave (μm) and average value a2 ave Calculate (μm). Average value a1ave and a2 ave Based on this, the formula is: (mean value a² ave (μm) - mean value a1 ave The value calculated using (μm) can be considered as the height A3 of the folds in the separation functional layer 1.

[0031] The thickness A2 of the protective layer 5 can be determined by the following method. First, elemental analysis is performed on the protective layer 5, and the weight m (g / m²) of a specific element per unit area of ​​the main surface of the protective layer 5 is determined. 2 ) is identified. Elemental analysis can be performed, for example, by X-ray fluorescence (XRF) analysis. Next, from the above weight m, the weight M (g / m²) of the material of the protective layer 5 per unit area of ​​the main surface of the protective layer 5 is determined. 2 Determine the density (g / m³) of the protective layer 5 material from its weight M. 3 The thickness A2 of the protective layer 5 can be calculated by dividing by ) and performing unit conversion. The density (true density) of the material of the protective layer 5 can be determined, for example, in accordance with the balance method specified in Japanese Industrial Standard (JIS) K0061:2001.

[0032] For example, if the material of protective layer 5 is polydimethylsiloxane (PDMS), the thickness A2 of protective layer 5 can be determined by the following method. First, the weight m of silicon (Si) per unit area of ​​the main surface of protective layer 5 is determined by elemental analysis. Si (g / m 2 Identify the weight m. Si Based on the atomic weight of silicon (28.09) and the molecular weight of one constituent unit of PDMS (composition formula: C2H6OSi) (74.15), the weight M of PDMS per unit area of ​​the main surface of the protective layer 5 is calculated using the following formula. PDMS (g / m 2 Calculate ). Weight M PDMS (g / m 2 )=weight m Si (g / m 2 ) × 74.15 / 28.09

[0033] Next, the weight M of PDMS per unit area of ​​the main surface of the protective layer 5. PDMS (g / m2 ), and the density of PDMS (980,000 g / m³). 3 Based on this, the thickness A2 of the protective layer 5 can be calculated using the following formula. Thickness A2 (μm) = Weight M PDMS (g / m 2 ) / 980000(g / m 3 ) × 10 6

[0034] The thickness A2 of the protective layer 5 is, for example, 50 μm or less, and may be 25 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, 0.5 μm or less, 0.4 μm or less, or even 0.3 μm or less. The smaller the thickness A2 of the protective layer 5, the more likely it is that the permeation rate of the permeating fluid passing through the separation membrane 10 will improve. The lower limit of the thickness A2 of the protective layer 5 is, for example, 0.01 μm or more, and may be 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, 0.1 μm or more, 0.15 μm or more, or even 0.2 μm or more, from the viewpoint of suppressing a decrease in separation performance. The thickness A2 of the protective layer 5 may be 0.3 μm (300 nm) or more, and may also be 0.4 μm (400 nm) or more, 0.5 μm (500 nm) or more, 0.6 μm (600 nm) or more, and even 0.7 μm (700 nm) or more. When the thickness A2 of the protective layer 5 is 0.3 μm or more (preferably 0.6 μm or more), the pressure resistance of the separation film 10 tends to be high. The thickness A2 of the protective layer 5 is preferably 0.01 μm to 50 μm.

[0035] From another aspect, the present invention Separation functional layer, A protective layer that protects the above-mentioned separation functional layer, Equipped with, The present invention provides a separation film in which the thickness of the protective layer described above is 600 nm to 5000 nm. This separation membrane tends to have particularly excellent pressure resistance. The thickness of the protective layer may be 650 nm to 2500 nm, or 700 nm to 1000 nm. In the above separation membrane, the ratio A2 / A1 of the thickness of the protective layer to the thickness A1 (μm) of the separation functional layer does not necessarily have to be 0.5 or more and less than 2.0, but may be, for example, 2.0 or more, and may be between 3.0 and 10.0.

[0036] (separation functional layer) The separation functional layer 1 is a layer that preferentially allows small molecules such as hydrogen and helium to pass through. Examples of materials for the separation functional layer 1 include polymers such as polyamide, cellulose ester, polyolefin, fluorine-containing polymer, and polysulfone; and inorganic materials such as ceramics. In the separation functional layer 1, the above polymers and inorganic materials may form a three-dimensional network skeleton. The separation functional layer 1 preferably contains at least one selected from the group consisting of polyamide, cellulose ester, polyolefin, fluorine-containing polymer, polysulfone, and ceramic, and is particularly preferably polyamide.

[0037] The polyamide contained in the separation functional layer 1 is preferably a polymer of a polyfunctional amine and a polyfunctional acid halogen.

[0038] Polyfunctional amines are compounds having two or more reactive amino groups, and include aromatic, aliphatic, and alicyclic polyfunctional amines.

[0039] Examples of aromatic polyfunctional amines include m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, N,N'-dimethyl-m-phenylenediamine, 2,4-diaminoanisole, amidol, xylylenediamine, and n-phenylethylenediamine.

[0040] Examples of aliphatic polyfunctional amines include ethylenediamine, propylenediamine, and tris(2-aminoethyl)amine.

[0041] Examples of alicyclic polyfunctional amines include 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, and 4-aminomethylpiperazine.

[0042] These polyfunctional amines may be used individually or in combination of two or more. It is preferable to use aromatic polyfunctional amines as the polyfunctional amines.

[0043] Polyfunctional acid halides are compounds having two or more reactive carbonyl groups, and include aromatic, aliphatic, and alicyclic polyfunctional acid halides.

[0044] Examples of aromatic polyfunctional acid halides include trimecinate trichloride, terephthalate dichloride, isophthalate dichloride, biphenyldicarboxylic acid dichloride, naphthalenedicarboxylic acid dichloride, benzenetrisulfonic acid trichloride, benzenedisulfonic acid dichloride, and chlorosulfonylbenzenedicarboxylic acid dichloride.

[0045] Examples of aliphatic polyfunctional acid halides include propanedicarboxylic acid dichloride, butanedicarboxylic acid dichloride, pentanedicarboxylic acid dichloride, propanetricarboxylic acid trichloride, butanetricarboxylic acid trichloride, pentanetricarboxylic acid trichloride, glutaryl halide, and adipoyl halide.

[0046] Examples of alicyclic polyfunctional acid halides include cyclopropanetricarboxylic acid trichloride, cyclobutanetetracarboxylic acid tetrachloride, cyclopentanetricarboxylic acid trichloride, cyclopentanetetracarboxylic acid tetrachloride, cyclohexanetricarboxylic acid trichloride, tetrahydrofurantetracarboxylic acid tetrachloride, cyclopentanedicarboxylic acid dichloride, cyclobutanedicarboxylic acid dichloride, cyclohexanedicarboxylic acid dichloride, and tetrahydrofrancolamine carboxylic acid dichloride.

[0047] These polyfunctional acid halides may be used individually or in combination of two or more. It is preferable to use aromatic polyfunctional acid halides. It is also preferable to use polyfunctional acid halides with a valency of three or higher to form a crosslinked structure.

[0048] Furthermore, in order to improve the performance of the separation functional layer 1 containing polyamide, polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid; and polyhydric alcohols such as sorbitol and glycerin may be copolymerized.

[0049] Examples of cellulose esters include cellulose acetate. Examples of polyolefins include polypropylene. Examples of fluorine-containing polymers include polytetrafluoroethylene (Teflon®).

[0050] In a preferred embodiment, the separation functional layer 1 may contain a polymer such as a polyamide as its main component, or may be composed substantially of a polymer alone. In this specification, “main component” means the component that is present in the most abundant amount by weight in the separation functional layer 1. The separation functional layer 1 may further contain other components other than polymers.

[0051] In another preferred embodiment, the separation functional layer 1 may contain an inorganic material such as ceramic as its main component, or may be composed substantially only of an inorganic material. The separation functional layer 1 may further contain other components other than the inorganic material.

[0052] The separation functional layer 1 may have a pleated microstructure. The pleats of this microstructure may penetrate into the interior of the protective layer 5. In some cases, the pleats of the microstructure may penetrate the protective layer 5 in the thickness direction. The pleated microstructure tends to form when the separation functional layer 1 contains polyamide.

[0053] The separation functional layer 1 typically has pores (micropores), and it is particularly preferable that it has a porous structure. The pores contained in this porous structure may be continuous pores formed in a three-dimensional manner. It is preferable that the separation functional layer 1 has through-holes that penetrate through the separation functional layer 1. However, the separation functional layer 1 may also have independent pores.

[0054] The average pore diameter of the porous separation functional layer 1 is preferably less than 10 nm, and may be 5 nm or less, 2 nm or less, or even 1 nm or less. The lower limit of the average pore diameter of the separation functional layer 1 is not particularly limited, but for example, it is 0.1 nm or more. The average pore diameter of the separation functional layer 1 can be determined by the following method. First, the surface of the separation functional layer 1 is observed with a transmission electron microscope (TEM). Next, the area of ​​a specific pore present in the obtained electron microscope image is calculated by image processing. The diameter of a circle having the same area as the calculated area is considered to be the diameter of that specific pore. The diameters of any number of pores (at least 20) are calculated, and the average of the calculated values ​​is considered to be the average pore diameter.

[0055] The pores of the separation functional layer 1 may be filled with the material of the protective layer 5 (e.g., a silicone-based polymer). In this case, the material may fill the entire pores of the separation functional layer 1 or only partially. Within the pores, tiny pathways may be formed between the materials (e.g., between silicone-based polymers) that allow small molecules (especially hydrogen) to pass through. When the pores of the separation functional layer 1 are filled with the material of the protective layer 5, the separation performance of the separation membrane 10 tends to improve further.

[0056] (protective layer) The protective layer 5 is a layer for protecting the separation function layer 1. The protective layer 5 preferably contains resin R. The contact angle of resin R with water is, for example, 60° or more. The contact angle with water can be evaluated using a sheet made of the resin to be evaluated by the static droplet method specified in Japanese Industrial Standard (JIS) R3257:1999. The contact angle of resin R with water is preferably 70° or more, and may be 80° or more, 90° or more, or even 100° or more. In this specification, resins with a contact angle with water of 90° or more are sometimes referred to as hydrophobic resins. The upper limit of the contact angle of resin R with water is not particularly limited, and may be, for example, 150° or less, or 120° or less.

[0057] The protective layer 5 preferably contains a silicone resin (silicone-based polymer) as the resin R. The protective layer 5 containing the silicone resin can be formed from a silicone resin composition. Examples of silicone resin compositions include addition-type silicone resin compositions and condensation-type silicone resin compositions. The protective layer 5 is preferably formed from an addition-type silicone resin composition or a condensation-type silicone resin composition, and is particularly preferably formed from a condensation-type silicone resin composition.

[0058] Addition-type silicone resin compositions are silicone resin compositions that cure by an addition reaction. An addition-type silicone resin composition may include, for example, a polyorganosiloxane P1 having an alkenyl group and a polyorganosiloxane P2 having a hydrosilyl (SiH) group. Preferably, the addition-type silicone resin composition further contains a curing catalyst (hydrosilylation catalyst). The addition-type silicone resin composition may also be a commercially available silicone resin composition to which a curing catalyst has been added. However, the addition-type silicone resin composition may not contain a curing catalyst.

[0059] Addition-type silicone resin compositions can be formed by, for example, heat treatment, which causes a reaction (hydrosilylation reaction) between the alkenyl group of polyorganosiloxane P1 and the hydrosilyl group of polyorganosiloxane P2, thereby forming a silicone resin. In this hydrosilylation reaction, polyorganosiloxane P2 functions as a crosslinking agent.

[0060] Examples of alkenyl groups in polyorganosiloxane P1 include vinyl groups and hexenyl groups. The number of alkenyl groups in polyorganosiloxane P1 is, for example, two or more. The alkenyl groups are located, for example, at the ends of polyorganosiloxane P1.

[0061] Polyorganosiloxane P1 is a polyorganosiloxane to which an alkenyl group has been introduced, such as polyalkylalkylsiloxanes (e.g., polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane), polyalkylarylsiloxanes, or poly(dimethylsiloxane-diethylsiloxane).

[0062] The weight-average molecular weight of polyorganosiloxane P1 is, for example, 1,000 or more, and may be 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or even 400,000 or more. The upper limit of the weight-average molecular weight of polyorganosiloxane P1 is not particularly limited, but is, for example, 1,000,000.

[0063] The number of hydrosilyl groups in polyorganosiloxane P2 is, for example, two or more. The hydrosilyl groups may be located at the ends of polyorganosiloxane P2, or they may be included in the main chain of polyorganosiloxane P2.

[0064] Examples of polyorganosiloxane P2 include polymethylhydrogensiloxane, poly(dimethylsiloxane-methylhydrogensiloxane), and hydrosilyl-terminated polydimethylsiloxane.

[0065] The weight-average molecular weight of polyorganosiloxane P2 is, for example, 100 or more, and may be 10,000 or more. The upper limit of the weight-average molecular weight of polyorganosiloxane P2 is not particularly limited, but is, for example, 1,000,000.

[0066] The weight ratio of polyorganosiloxane P2 to polyorganosiloxane P1, P2 / P1, is, for example, 500 wt% or less, and may also be 100 wt% or less, 50 wt% or less, 20 wt% or less, 10 wt% or less, or even 5 wt% or less. The lower limit of the weight ratio P2 / P1 is, for example, 0.01 wt% or more.

[0067] Examples of curing catalysts included in addition-type silicone resin compositions include platinum-based catalysts. Specific examples of platinum-based catalysts include chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes.

[0068] Addition-type silicone resin compositions may contain compounds that generate catalytically active species that catalyze addition reactions when irradiated with active energy rays such as ultraviolet (UV) light. According to an addition-type silicone resin composition containing such compounds, the addition reaction can be carried out, for example, by UV irradiation.

[0069] The addition-type silicone resin composition may further contain organic solvents, curing retarders, etc., in addition to the components described above. Examples of organic solvents include hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; and alcohol solvents such as methanol, ethanol, and butanol. The organic solvent may be used alone or in combination of two or more. The addition-type silicone resin composition may also be a solvent-free type that does not contain solvents such as organic solvents.

[0070] A condensation-type silicone resin composition is a type of silicone resin composition that hardens by a condensation reaction. Preferably, the condensation-type silicone resin composition contains polyorganosiloxane P3 having a silanol (SiOH) group. The condensation-type silicone resin composition may or may not contain a silane compound P4 having functional groups such as alkoxy groups, alkenyloxy groups, acyloxy groups, amino groups, ketoxime groups, or amide groups, along with the polyorganosiloxane P3. The condensation-type silicone resin composition may or may not further contain a curing catalyst. Note that the condensation-type silicone resin composition may also be a commercially available silicone resin composition to which a curing catalyst has been added.

[0071] As an example, in a condensation-type silicone resin composition, a reaction (condensation reaction) between the silanol group of polyorganosiloxane P3 and the above-mentioned functional group of silane compound P4 proceeds by heat treatment, thereby forming a silicone resin. In this condensation reaction, silane compound P4 functions as a crosslinking agent. In addition, multiple polyorganosiloxane P3 molecules may be condensed via their silanol groups by the above heat treatment.

[0072] The number of silanol groups in polyorganosiloxane P3 is, for example, two or more. The silanol groups are located, for example, at the terminal ends of polyorganosiloxane P3. Polyorganosiloxane P3 may also have alkyl groups such as methyl or ethyl groups, or phenyl groups introduced as substituents on its side chains.

[0073] Polyorganosiloxane P3 is, for example, a polyorganosiloxane P1, to which a silanol group has been introduced.

[0074] The weight-average molecular weight of polyorganosiloxane P3 is, for example, 1,000 or more, and may be 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or even 400,000 or more. The upper limit of the weight-average molecular weight of polyorganosiloxane P3 is not particularly limited, and is, for example, 1,000,000.

[0075] As described above, silane compound P4 has functional groups such as alkoxy groups, alkenyloxy groups, acyloxy groups, amino groups, ketoxime groups, and amide groups. Examples of alkoxy groups include methoxy groups and ethoxy groups. Examples of alkenyloxy groups include isopropenyloxy groups. Examples of acyloxy groups include acetoxy groups. Examples of amino groups include dimethylamino groups, diethylamino groups, and ethylmethylamino groups. Examples of ketoxime groups include acetoxime groups and methylethylketoxime groups. Examples of amide groups include acetamide groups, N-methylacetamide groups, and N-ethylacetamide groups. The number of functional groups in silane compound P4 is, for example, two or more. More specifically, silane compound P4 preferably contains an alkoxysilyl group as an alkoxy group.

[0076] The silane compound P4 may be a low molecular weight compound with a molecular weight of approximately 1000 or less, or it may be a high molecular weight compound having a polysiloxane skeleton.

[0077] Examples of curing catalysts included in condensation-type silicone resin compositions include tin-based catalysts. Examples of tin-based catalysts include organotin catalysts such as dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin dioctate.

[0078] The condensation-type silicone resin composition may further contain organic solvents, curing retarders, and other components in addition to those described above. Examples of organic solvents include those described above for the addition-type silicone resin composition. The condensation-type silicone resin composition may also be solvent-free, meaning it does not contain solvents such as organic solvents. Examples of curing retarders for the condensation-type silicone resin composition include acetylacetone.

[0079] The total free volume parameter of the silicone resin contained in the protective layer 5 is preferably 10 or greater. In this case, the permeation rate of the permeating fluid that permeates through the separation membrane 10 tends to improve. The upper limit of the total free volume parameter of the silicone resin is not particularly limited, but for example, it may be 20 or less.

[0080] The total free volume parameter is the free volume V (nm). 3 This corresponds to the value obtained by multiplying the free volume V by the relative signal intensity I (%) (free volume V × relative signal intensity I). The free volume V and relative signal intensity I can be calculated from the measurement results of the positron lifetime spectrum of the silicone resin.

[0081] The protective layer 5 may contain resin R as its main component, or may be composed substantially of resin R alone. The protective layer 5 may further contain other components other than resin R (for example, the curing catalyst described above).

[0082] (porous support) The separation membrane 10 may further include a porous support 3 that supports the separation functional layer 1. In this case, it is preferable that the separation functional layer 1 in the separation membrane 10 is located between the protective layer 5 and the porous support 3 and is in direct contact with both the protective layer 5 and the porous support 3.

[0083] The porous support 3 may be an ultrafiltration membrane in which a microporous layer having an average pore size of 0.01 to 0.4 μm is formed on a nonwoven fabric. In this case, it is preferable that the microporous layer is in direct contact with the separation functional layer 1. The average pore size of the microporous layer can be determined for the separation functional layer 1 by the method described above.

[0084] Examples of materials for the microporous layer include polysulfone, polyaryl ethersulfone such as polyethersulfone, polyimide, polyetherimide, and polyvinylidene fluoride. From the viewpoint of chemical stability, mechanical stability, and thermal stability, the microporous layer preferably contains polysulfone. The thickness of the microporous layer is not particularly limited, and is, for example, 10 μm to 35 μm.

[0085] Examples of nonwoven fabric materials include polyolefins, polyesters, and cellulose. From the viewpoint of moldability, it is preferable that the nonwoven fabric contains polyester. The nonwoven fabric may be a long-fiber nonwoven fabric or a short-fiber nonwoven fabric. The thickness of the nonwoven fabric is not particularly limited, but is for example 50 μm to 90 μm.

[0086] Furthermore, the laminate of the separation functional layer 1 and the porous support 3 may function as a filtration membrane such as a reverse osmosis membrane (RO membrane) or a nanofiltration membrane (NF membrane). In this specification, an RO membrane means a membrane that removes 93% or more of sodium chloride when filtering a test solution with a sodium chloride concentration of 2000 mg / L at an operating pressure of 1.5 MPa. An NF membrane means a membrane that removes 5% or more and less than 93% of sodium chloride when filtering a test solution with a sodium chloride concentration of 2000 mg / L at an operating pressure of 1.5 MPa.

[0087] (Shape of the separation membrane) In this embodiment, the separation membrane 10 is typically a flat membrane. However, the separation membrane 10 may have a shape other than a flat membrane, and may be a hollow fiber membrane.

[0088] (Method for manufacturing separation membranes) The separation membrane 10 can be fabricated, for example, by the following method. First, a separation functional layer 1 is formed on a porous support 3 (more specifically, a microporous layer of the porous support 3). As an example, the separation functional layer 1 containing polyamide can be fabricated using methods such as interfacial condensation, phase separation, or thin-film coating. Interfacial condensation methods include forming the separation functional layer 1 by bringing an amine aqueous solution containing a polyfunctional amine into contact with an organic solution containing a polyfunctional acid halide and performing interfacial polymerization, and then placing the separation functional layer 1 on the porous support 3, or directly forming the separation functional layer 1 containing polyamide on the porous support 3 by interfacial polymerization on the porous support 3. Details of interfacial condensation methods are described in Japanese Patent Publication No. 58-24303, Japanese Patent Publication No. 1-180208, and others.

[0089] Next, a separation membrane 10 can be fabricated by forming a protective layer 5 on the separation functional layer 1. The protective layer 5 can be formed, for example, by the following method. First, a coating solution (e.g., a silicone resin composition) containing the material for the protective layer 5 is prepared. The viscosity and solid content concentration of the coating solution can be appropriately adjusted according to the desired thickness of the protective layer 5. The solid content concentration of the coating solution is, for example, 0.1 wt% to 30 wt%, and may also be 1 wt% to 5 wt%.

[0090] Next, a coating solution is applied onto the separation functional layer 1 to form a coating film. The method of applying the coating solution is not particularly limited, and for example, spin coating, dip coating, slot die coating, gravure coating, comma coating, etc., can be used. The coating solution may also be applied to the separation functional layer 1 using an applicator or wire bar. The application conditions for the coating solution can be appropriately adjusted according to the desired thickness of the protective layer 5. As an example, when applying the coating solution by spin coating, the rotation speed of the spin coater may be, for example, 100 to 5000 rpm, or 1000 to 2000 rpm.

[0091] Next, a protective layer 5 is formed by curing the coating film. The coating film can be cured at room temperature or in a heated environment. When curing the coating film by heating, the heating conditions for the coating film are not particularly limited. For example, the heating temperature of the coating film may be 80°C or higher, 90°C or higher, 100°C or higher, or even 120°C or higher. The upper limit of the heating temperature of the coating film is not particularly limited, for example, 200°C. The heating time of the coating film can be appropriately adjusted according to the composition of the coating film.

[0092] The separation membrane 10 may be manufactured using a roll-to-roll method. That is, a long porous support 3 may be unwound from a winding of the porous support 3, and the separation functional layer 1 and protective layer 5 may be formed while the porous support 3 is being transported. It is preferable that the formation of the separation functional layer 1 and the protective layer 5 be carried out continuously. However, after the formation of the separation functional layer 1, the long laminate comprising the porous support and the separation functional layer may be wound up once. In this case, the separation membrane 10 can be manufactured by unwounding the long laminate again and forming the protective layer 5 while transporting the laminate. A winding of the obtained separation membrane 10 may also be manufactured by winding up the separation membrane 10. The roll-to-roll method is suitable for mass production of the separation membrane 10.

[0093] Furthermore, if the separation functional layer 1 has pores, applying a coating liquid (e.g., a silicone resin composition) onto the separation functional layer 1 may cause a portion of the coating liquid to fill the pores of the separation functional layer 1. As the coating liquid hardens inside the pores, the material of the protective layer 5 (e.g., a silicone-based polymer) fills the pores of the separation functional layer 1. In this case, within the pores, tiny pathways tend to be formed between the materials (e.g., between silicone-based polymers) through which small molecules (especially hydrogen) can pass.

[0094] (Characteristics of the separation membrane) The separation membrane 10 in this embodiment is typically a membrane that preferentially allows hydrogen to permeate from a hydrogen-containing gas mixture. More specifically, the separation membrane 10 can preferentially allow small molecules such as hydrogen and helium to permeate, while suppressing the permeation of relatively large molecules such as carbon dioxide, nitrogen, and methane.

[0095] For example, the separation membrane 10 tends to have a high separation coefficient for hydrogen relative to methane. The separation coefficient for hydrogen relative to methane is similar to the separation coefficient for helium relative to nitrogen α. He / N2 There is a tendency for it to correlate with the separation coefficient α of helium relative to nitrogen. He / N2 Therefore, the separation coefficient of hydrogen from methane can be predicted to some extent.

[0096] In the separation membrane 10, the separation coefficient α of helium relative to nitrogen. He / N2 For example, it may be 200 or more, and may also be 300 or more, 400 or more, 500 or more, or even 600 or more. Separation coefficient α He / N2 There is no particular upper limit; for example, it could be 1000 or less.

[0097] Separation coefficient α He / N2 This is the rate of nitrogen permeation T when nitrogen at a pressure of 0.6 MPa is supplied to the space adjacent to one side of the separation membrane 10. N2 The helium permeation rate T for the GPU when helium at a pressure of 0.6 MPa is supplied to the space in question and the helium permeates through the separation membrane 10. He (GPU) ratio T He / T N2 This means that. Furthermore, unless otherwise specified in this specification, "pressure" refers to absolute pressure.

[0098] Helium permeability T He This can be measured in detail by the following method. First, prepare the separation membrane 10 to be measured. The membrane area of ​​the separation membrane 10 to be measured is, for example, 0.43 cm². 2Next, helium at a pressure of 0.6 MPa and a temperature of 25°C is supplied to the space adjacent to one side of the separation membrane 10 (for example, the main surface 11 on the protective layer side of the separation membrane 10). As a result, permeate fluid (helium) that has permeated through the separation membrane 10 is obtained from the other main surface of the separation membrane 10 (for example, the main surface 12 on the porous support side of the separation membrane 10). The flow rate of this permeate fluid is measured with a mass flow meter, and from the obtained result, the helium permeation rate T is determined. He Identify the (GPU). Depending on the flow rate of the permeating fluid, a soap film flow meter may be used instead of a mass flow meter.

[0099] Helium permeability T He For example, it may be 100 GPUs or more, 105 GPUs or more, 110 GPUs or more, 115 GPUs or more, 120 GPUs or more, or even 125 GPUs or more. Transmission speed T He The upper limit is not particularly limited, for example, 500 GPU or less. Note that the permeation rate of hydrogen passing through the separation membrane 10 is the same as the permeation rate of helium T He There is a tendency for it to correlate with the helium permeation rate T. He Therefore, the hydrogen permeation rate can be predicted to some extent. In this specification, the GPU is 10 -6 ·cm 3 (STP) / (sec·cm 2 This means cmHg. 3 (STP) refers to the volume of a gas at 1 atmosphere and 0°C.

[0100] Nitrogen permeation rate T N2 Except for using nitrogen at a pressure of 0.6 MPa and a temperature of 25°C instead of helium, the helium permeation rate T He This can be measured by the method described above. Nitrogen permeation rate T N2 For example, this ranges from 0.01 GPU to 1.0 GPU.

[0101] Furthermore, the separation membrane 10 tends to have a high separation coefficient for hydrogen relative to carbon dioxide. Note that the separation coefficient for hydrogen relative to carbon dioxide is equal to the separation coefficient for helium relative to carbon dioxide α He / CO2There is a tendency for it to correlate with the separation coefficient α of helium for carbon dioxide. He / CO2 Therefore, the separation coefficient of hydrogen from carbon dioxide can be predicted to some extent.

[0102] In the separation membrane 10, the separation coefficient α of helium relative to carbon dioxide. He / CO2 For example, it may be 20 or more, and may also be 25 or more, 30 or more, or even 35 or more. Separation coefficient α He / CO2 There is no particular upper limit; for example, it could be 100 or less.

[0103] Separation coefficient α He / CO2 This is the permeation rate T of carbon dioxide that passes through the separation membrane 10 when carbon dioxide at a pressure of 0.6 MPa is supplied to the space adjacent to one side of the separation membrane 10. CO2 The helium permeation rate T for the GPU when helium at a pressure of 0.6 MPa is supplied to the space in question and the helium permeates through the separation membrane 10. He (GPU) ratio T He / T CO2 It means...

[0104] Carbon dioxide permeation rate T CO2 Except for using carbon dioxide at a pressure of 0.6 MPa and a temperature of 25°C instead of helium, the helium permeation rate T He This can be measured by the method described above. The permeation rate of carbon dioxide T CO2 For example, this ranges from 0.1GPU to 5.0GPU.

[0105] (Applications of separation membranes) One application of the separation membrane 10 in this embodiment is the separation of hydrogen from a gas mixture containing hydrogen. In particular, the separation membrane 10 is suitable for separating hydrogen from a gas mixture containing hydrogen and methane, or from a gas mixture containing hydrogen and carbon dioxide. However, the applications of the separation membrane 10 are not limited to separating hydrogen from the above-mentioned gas mixtures. For example, the separation membrane 10 may be used to separate helium from a gas mixture containing helium.

[0106] <Embodiment of a membrane separation apparatus> As shown in Figure 2, the membrane separation apparatus 100 of this embodiment comprises a separation membrane 10 and a tank 20. The tank 20 comprises a first chamber 21 and a second chamber 22. The separation membrane 10 is located inside the tank 20. Inside the tank 20, the separation membrane 10 separates the first chamber 21 and the second chamber 22. The separation membrane 10 extends from one of a pair of walls of the tank 20 to the other.

[0107] The first chamber 21 has an inlet 21a and an outlet 21b. The second chamber 22 has an outlet 22a. Preferably, each of the inlet 21a, outlet 21b, and outlet 22a is an opening formed in the wall surface of the tank 20.

[0108] Membrane separation using the membrane separation apparatus 100 is performed, for example, by the following method. First, a hydrogen-containing gas mixture 30 is supplied to the first chamber 21 through the inlet 21a. The hydrogen concentration in the gas mixture 30 is not particularly limited, and under standard conditions, is, for example, 0.01 vol% (100 ppm) or more, preferably 1 vol% or more, more preferably 10 vol% or more, even more preferably 30 vol% or more, and particularly preferably 50 vol% or more. The upper limit of the hydrogen concentration in the gas mixture 30 is not particularly limited, and under standard conditions, is, for example, 90 vol%.

[0109] The pressure inside the first chamber 21 may be increased by supplying the mixed gas 30. The membrane separator 100 may further include a pump (not shown) for increasing the pressure of the mixed gas 30. The pressure of the mixed gas 30 supplied to the first chamber 21 is, for example, 0.1 MPa or more, preferably 0.3 MPa or more.

[0110] The second chamber 22 may be depressurized while the mixed gas 30 is supplied to the first chamber 21. The membrane separation device 100 may further include a pump (not shown) for depressurizing the second chamber 22. The second chamber 22 may be depressurized such that the space inside the second chamber 22 is, for example, 10 kPa or more, preferably 50 kPa or more, and more preferably 100 kPa or more, than the atmospheric pressure in the measurement environment.

[0111] By supplying the mixed gas 30 into the first chamber 21, a permeate fluid 35 with a higher hydrogen content than the mixed gas 30 can be obtained on the other side of the separation membrane 10. That is, the permeate fluid 35 is supplied to the second chamber 22. Preferably, the permeate fluid 35 contains hydrogen as its main component. However, the permeate fluid 35 may also contain small amounts of other gases besides hydrogen. The permeate fluid 35 is discharged to the outside of the tank 20 through the outlet 22a.

[0112] The hydrogen concentration in the gas mixture 30 gradually decreases from the inlet 21a to the outlet 21b of the first chamber 21. The gas mixture 30 (impermeable fluid 36) treated in the first chamber 21 is discharged to the outside of the tank 20 through the outlet 21b.

[0113] The membrane separation apparatus 100 of this embodiment is suitable for a continuous flow membrane separation method. However, the membrane separation apparatus 100 of this embodiment may also be used for a batch membrane separation method.

[0114] <Modified example of a membrane separation device> The membrane separation device 100 may be a spiral-type membrane element, a hollow fiber membrane element, or the like. Figure 3 shows a spiral-type membrane element. The membrane separation device 110 in Figure 3 comprises a central tube 41 and a laminate 42. The laminate 42 contains the separation membrane 10.

[0115] The central tube 41 has a cylindrical shape. Multiple holes are formed on the surface of the central tube 41 to allow the permeable fluid 35 to flow into the interior of the central tube 41. Examples of materials for the central tube 41 include resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyphenylene ether resin (PPE resin), and polysulfone resin (PSF resin); and metals such as stainless steel and titanium. The inner diameter of the central tube 41 is, for example, in the range of 20 to 100 mm.

[0116] The laminate 42 further includes a supply-side channel material 43 and a permeate-side channel material 44 in addition to the separation membrane 10. The laminate 42 is wound around the central tube 41. The membrane separation device 110 may further include an outer casing material (not shown).

[0117] For the supply-side channel material 43 and the permeate-side channel material 44, for example, a resin net made of polyphenylene sulfide (PPS) or ethylene-chlorotrifluoroethylene copolymer (ECTFE) can be used.

[0118] Membrane separation using the membrane separation device 110 is performed by the following method. First, a mixed gas 30 is supplied to one end of the wound laminate 42. The permeate fluid 35 that has permeated through the separation membrane 10 of the laminate 42 moves into the center tube 41. The permeate fluid 35 is discharged to the outside through the center tube 41. The mixed gas 30 (impermeable fluid 36) processed by the membrane separation device 110 is discharged to the outside from the other end of the wound laminate 42. This allows hydrogen to be separated from the mixed gas 30. [Examples]

[0119] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0120] (Example 1) First, a porous support was prepared, consisting of a polyester nonwoven fabric with a microporous layer of polysulfone formed on top. Next, an aqueous amine solution containing 3.0 wt% m-phenylenediamine (MPD), 0.15 wt% sodium dodecyl sulfate, 2.15 wt% triethylamine, 0.31 wt% sodium hydroxide, 6 wt% camphor sulfonic acid, and 1 wt% isopropyl alcohol was applied to the microporous layer of the porous support, and a coating film was prepared by removing the excess aqueous amine solution.

[0121] Next, an acid chloride solution was prepared by dissolving 0.075 wt% trimecinate trichloride (TMC) and 0.113 wt% isophthalate dichloride (IPC) in a naphthenic solvent (ExxonMobil, Exxsol D40). The surface of the above-mentioned coated film was immersed in this acid chloride solution for 7 seconds. Excess solution was removed from the surface of the coated film, it was air-dried for 20 seconds, and then held in a hot air dryer at 140°C for 3 minutes. This formed a separation functional layer containing polyamide on the porous support.

[0122] Next, 4.00 g of a condensation-type silicone resin composition (YSR3022, manufactured by Momentive Performance Materials Japan, toluene-MEK solution, solids content 30 wt%) was mixed with 55.84 g of n-heptane (manufactured by Sankyo Chemical Co., Ltd.) as a diluent, 0.040 g of a tin-based catalyst (YC6831, manufactured by Momentive Performance Materials Japan, Manufactured by YC6831) as a curing catalyst, and 0.120 g of acetylacetone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a curing retarder to prepare a coating solution (condensation-type silicone resin composition). The solids content concentration of this coating solution was 2 wt%.

[0123] Next, a coating film was obtained by applying 8 mL of the above coating solution onto the separation functional layer using a spin coater. The operating conditions of the spin coater were a set rotation speed of 2000 rpm, a time to reach the set rotation speed of 20 seconds, and a time to maintain the set rotation speed of 10 seconds. Next, a protective layer was prepared by heating the coating film at 120°C for 5 minutes to cure it. This obtained the separation film of Example 1.

[0124] (Examples 2-8) Separation membranes of Examples 2 to 8 were obtained by the same method as in Example 1, except that the composition of the coating solution applied to the separation functional layer and the rotation speed of the spin coater were changed as shown in Table 1.

[0125] [Thickness of the separation layer and height of the pleats] The cross-section of the fabricated separation membrane was observed at three points using a transmission electron microscope (TEM) (manufactured by Hitachi High-Technologies Corporation, "HT-7820"), and the thickness A1 of the separation functional layer and the height A3 of the fold were specified by the method described above. The observation by TEM was performed at a magnification of 20,000 times.

[0126] [Thickness of the protective layer] Regarding the protective layer in the fabricated separation membrane, fluorescence X-ray (XRF) analysis was performed using a fluorescence X-ray analyzer (manufactured by Rigaku Corporation, "ZSX PrimusIII+"). In each case, since the protective layer was substantially composed of only polydimethylsiloxane (PDMS), in the XRF analysis, the weight m of silicon (Si) per unit area of the main surface of the protective layer Si (g / m 2 ) was specified. Based on the weight m Si , the atomic weight of silicon (28.09), and the molecular weight (74.15) per constituent unit (composition formula: C2H6OSi) of PDMS, the weight M of PDMS per unit area of the main surface of the protective layer was calculated by the above calculation formula. PDMS (g / m 2 ) was calculated. Further, based on the weight M PDMS (g / m 2 ) and the density of PDMS (980,000 g / m 3 ), the thickness A2 of the protective layer was calculated by the above calculation formula.

[0127] [Characteristic evaluation of the separation membrane] Regarding the fabricated separation membrane, the helium permeation rate T He was measured by the following method. First, the separation membrane (membrane area: 0.43 cm 2 ) was set in a metal cell and sealed with an O-ring so that no leakage occurred. Next, helium at a pressure of 0.6 MPa and a temperature of 25 °C was injected into the metal cell so that it contacted the main surface on the protective layer side of the separation membrane. As a result, the permeating fluid (helium) was obtained from the main surface on the porous support side of the separation membrane. The flow rate of the obtained permeating fluid was measured, and the helium permeation rate T He was calculated.

[0128] Furthermore, regarding the fabricated separation membrane, the nitrogen permeation rate TN2 and the permeation rate T of carbon dioxide CO2 were measured. The permeation rate T of nitrogen N2 was measured by the method described above for the permeation rate T of helium, except that nitrogen at a pressure of 0.6 MPa and a temperature of 25°C was used instead of helium. He Similarly, the permeation rate T of carbon dioxide CO2 was measured by the method described above for the permeation rate T of helium, except that carbon dioxide at a pressure of 0.6 MPa and a temperature of 25°C was used instead of helium. He was measured.

[0129] Based on the obtained results, the ratio T N2 (GPU) of the permeation rate T of helium to the permeation rate T of nitrogen He (GPU) was calculated, and the calculated value was regarded as the separation factor α of helium with respect to nitrogen He / T N2 . Further, the ratio T He / N2 (GPU) of the permeation rate T of helium to the permeation rate T of carbon dioxide CO2 (GPU) was calculated, and the calculated value was regarded as the separation factor α of helium with respect to carbon dioxide He (GPU) He / T CO2 . He / CO2

[0130] [Table 1]

[0131] [Table 2]

[0132] The abbreviations in Table 1 are as follows. YSR3022: Condensed silicone resin composition (manufactured by Momentive Performance Materials Japan, YSR3022) SD7328: Addition type silicone resin composition (manufactured by Dow Corning Toray Co., Ltd., SD7328) ​BY24-489: Addition-type silicone resin composition (manufactured by Dow-Toray, BY24-489) YC6831: Tin-based catalyst (manufactured by Momentive Performance Materials Japan, YC6831) SRX212: Curing catalyst (manufactured by Dow Toray, SRX212)

[0133] As can be seen from Table 2, the separation membranes in Examples 1-3, where the ratio of the thickness of the protective layer A2 (μm) to the thickness of the separation functional layer A1 (μm) is A2 / A1, is 0.5 or more and less than 2.0, have a helium permeation rate T He , the separation coefficient α of helium relative to nitrogen He / N2 , and the separation coefficient α of helium for carbon dioxide He / CO2 All of these values ​​were high. As mentioned above, the helium permeability rate and separation coefficient tend to correlate with the hydrogen permeability rate and separation coefficient. Therefore, it can be inferred that the separation membranes in Examples 1-3 have high hydrogen permeability and high hydrogen separation performance. The separation membranes in Examples 1-3 can be said to be suitable for separating hydrogen from a hydrogen-containing gas mixture.

[0134] As can be seen from Table 2, the separation membranes in Examples 4-6, where the ratio A2 / A1 is less than 0.5, have a separation coefficient α He / N2 and separation coefficient α He / CO2 The value was smaller than in Examples 1-3. Separation membranes in Examples 7-8, where the ratio A2 / A1 is greater than 2.0, had a helium permeation rate T He or, the separation coefficient α He / CO2 The value was smaller than that in Examples 1-3.

[0135] <Pressure resistance test> Below, we fabricated separation membranes for Examples 9-14 and performed pressure resistance tests 1-2 on these membranes.

[0136] (Examples 9-11) The separation membranes of Examples 9-11 were prepared using the same method as in Example 1, except that the protective layer was formed under the conditions shown in Table 3. The thickness A2 of the protective layer was determined using the method described above for Examples 1-8.

[0137] [Table 3]

[0138] The abbreviations used in Table 3 are as follows: YSR3022: Condensation-type silicone resin composition (manufactured by Momentive Performance Materials Japan, YSR3022) YC6831: Tin-based catalyst (manufactured by Momentive Performance Materials Japan, YC6831)

[0139] (Example 12) The separation membrane of Example 12 was prepared by the following method. First, a separation functional layer containing polyamide was formed on the porous support using the same method as in Example 1, except that a long porous support was used. This resulted in a long laminate comprising the porous support and the separation functional layer.

[0140] Next, 2154 g of addition-type silicone resin composition (Dow-Toray, SD7328) was mixed with 8618 g of n-heptane (Sankyo Chemical Co., Ltd.) as a diluent and 12.9 g of curing catalyst (Dow-Toray, SRX212) to prepare a coating solution (addition-type silicone resin composition). The solid content concentration of this coating solution was 6 wt%.

[0141] Next, a long, laminated structure was unfurled, and the coating solution was applied to it while the laminate was being transported. The coating solution was applied using the gravure coating method. The cell volume of the gravure coater used at this time was 9.1 cm³. 3 / m 2 Next, a protective layer was created by heating and curing the coated film. This yielded the separation film of Example 12. The thickness A2 of the protective layer was determined using the method described above for Examples 1 to 8.

[0142] (Examples 13 and 14) The separation films of Examples 13 and 14 were obtained by the same method as in Example 12, except that the composition of the coating solution applied on the separation functional layer and the cell volume of the gravure coater were changed as shown in Table 4. The thickness A2 of the protective layer was determined by the method described above for Examples 1 to 8.

[0143] [Table 4]

[0144] The abbreviations used in Table 4 are as follows: SD7328: Addition-type silicone resin composition (manufactured by Dow Toray, SD7328) SRX212: Curing catalyst (manufactured by Dow Toray, SRX212)

[0145] [Pressure resistance test 1] Pressure resistance test 1 was performed using the following method. First, the separation membrane (membrane area 0.43 cm²) 2 The membrane was placed in a metal cell and sealed with an O-ring to prevent leaks. Next, nitrogen at a temperature of 25°C was injected into the metal cell so that it came into contact with the main surface of the protective layer side of the separation membrane. At this time, the amount of nitrogen injected was adjusted so that the pressure (gauge pressure) in the supply space was 1.0 MPa. As a result, permeate fluid (nitrogen) was obtained from the main surface of the porous support side of the separation membrane. The flow rate of the obtained permeate fluid was measured and the nitrogen permeation rate was calculated.

[0146] Next, the pressure (gauge pressure) in the supply space of the metal cell was increased by approximately 1.0 MPa at a time, and the nitrogen permeation rate was determined each time. Furthermore, after the pressure in the supply space was increased to 6.0 MPa, the pressure was decreased by approximately 1.0 MPa at a time, and the nitrogen permeation rate was determined each time. The results are shown in Figures 4 and 5. In Figures 4 and 5, circles (〇) indicate the results when the pressure in the supply space was increased, and squares (□) indicate the results when the pressure in the supply space was decreased.

[0147] As can be seen from the results in Figures 4 and 5, in Examples 9-14, the nitrogen permeation rate returned to its original value as the pressure in the supply space decreased from 6.0 MPa. From this result, it can be seen that no defects occurred in the separation membrane during pressure resistance test 1 in Examples 9-14.

[0148] [Pressure resistance test 2] Pressure resistance test 2 was performed using the following method. First, the separation membrane (membrane area 0.43 cm²) 2 The ) was placed in a metal cell and sealed with an O-ring to prevent leaks. Next, carbon dioxide at a temperature of 25°C was injected into the metal cell so that it came into contact with the main surface of the protective layer side of the separation membrane. At this time, the amount of carbon dioxide injected was adjusted so that the pressure (gauge pressure) in the supply space was 1.0 MPa. As a result, permeate fluid (carbon dioxide) was obtained from the main surface of the porous support side of the separation membrane. The flow rate of the obtained permeate fluid was measured and the permeation rate of carbon dioxide was calculated.

[0149] Next, the pressure (gauge pressure) in the supply space of the metal cell was increased by approximately 1.0 MPa at a time, and the carbon dioxide permeation rate was determined each time. Furthermore, after the pressure in the supply space was increased to approximately 3.0 MPa, the pressure was decreased by approximately 1.0 MPa at a time, and the carbon dioxide permeation rate was determined each time. The results are shown in Figures 6 and 7. In Figures 6 and 7, circles (〇) indicate the results when the pressure in the supply space was increased, and squares (□) indicate the results when the pressure in the supply space was decreased.

[0150] As can be seen from the results in Figures 6 and 7, in Examples 9 and 12, where the protective layer thickness was less than 0.3 μm and relatively thin, the carbon dioxide permeation rate increased as the pressure in the supply space of the metal cell increased. From this result, it can be seen that the separation membranes in Examples 9 and 12 have low pressure resistance. On the other hand, in Examples 10, 11, 13, and 14, where the protective layer thickness was 0.3 μm or more, the increase in the carbon dioxide permeation rate was suppressed even when the pressure in the supply space of the metal cell increased, resulting in high pressure resistance. Furthermore, in Examples 9 to 14, the carbon dioxide permeation rate returned to its original value as the pressure in the supply space decreased from 3.0 MPa. From this result, it can be seen that no defects occurred in the separation membranes in Examples 9 to 14 during Pressure Test 2. [Industrial applicability]

[0151] The separation membrane of this embodiment is suitable for separating hydrogen from a hydrogen-containing gas mixture.

Claims

1. A separation functional layer having a pleated microstructure, A protective layer that protects the separation functional layer, Equipped with, The ratio A2 / A1 of the thickness of the protective layer to the thickness A1 (μm) of the separation functional layer is 0.5 or more and less than 2.

0. A separation membrane in which the height A3 of the folds in the separation functional layer is 0.1 μm or more and 1 μm or less.

2. The separation membrane according to claim 1, wherein the thickness A1 is 0.01 μm to 50 μm.

3. The separation membrane according to claim 1, wherein the thickness A2 is 0.01 μm to 50 μm.

4. The separation membrane according to claim 1, wherein the separation functional layer comprises at least one selected from the group consisting of polyamide, cellulose ester, polyolefin, fluorine-containing polymer, polysulfone, and ceramic.

5. The separation membrane according to claim 1, wherein the protective layer comprises a silicone resin.

6. The separation membrane according to claim 1, wherein the protective layer is formed from an addition-type silicone resin composition or a condensation-type silicone resin composition.

7. The separation membrane according to claim 1, wherein the protective layer is in direct contact with the separation functional layer.

8. The separation membrane according to claim 1, further comprising a porous support for supporting the separation functional layer.

9. When helium at a pressure of 0.6 MPa is supplied to the space adjacent to one side of the separation membrane, the permeation rate T of helium that passes through the separation membrane is... He The separation membrane according to claim 1, wherein the capacity is 100 GPU or more.

10. Separation coefficient α of helium relative to nitrogen He / N2 The separation membrane according to claim 1, wherein the value is 200 or more. Here, the separation coefficient α He / N2 This is the rate of nitrogen permeation through the separation membrane when nitrogen at a pressure of 0.6 MPa is supplied to the space adjacent to one side of the separation membrane. N2 The helium permeation rate T through the separation membrane when helium at a pressure of 0.6 MPa is supplied to the space (GPU) He (GPU) ratio T He / T N2 It means...

11. The separation coefficient α of helium from carbon dioxide He / CO2 The separation membrane according to claim 1, wherein the ratio is 20 or more. Here, the separation coefficient α He / CO2 is the permeation rate T CO2 of carbon dioxide that permeates through the separation membrane when carbon dioxide at a pressure of 0.6 MPa is supplied to the space adjacent to one surface of the separation membrane, with respect to the permeation rate T He (GPU) of helium that permeates through the separation membrane when helium at a pressure of 0.6 MPa is supplied to the space. He The ratio T CO2 / T

1. means.

12. A separation membrane according to claim 1, used for separating hydrogen from a hydrogen-containing gas mixture.