Pervaporation gasification membranes

Abstract

Provided is a pervaporation membrane suitable for improved separation performance in separating a volatile organic compound from an aqueous solution containing the organic compound. The pervaporation membrane 10 of the present invention has a separation function layer 1 having a porous layer 2 containing pores 4 and a skin layer 3 formed on the porous layer 2. The pervaporation membrane 20 of the present invention further has a porous support 5 that supports the separation function layer 1.

Description

Technical Field

[0001] This invention relates to pervaporation membranes. Background Technology

[0002] As a method for obtaining valuable substances derived from non-petroleum sources, methods utilizing microbial fermentation are known. For example, a method has been developed to produce volatile organic compounds (fermented products) such as alcohols by fermenting carbon sources like glucose using microorganisms. The fermentation of the carbon source is carried out, for example, in an aqueous solution. In this method, if the content of the fermented product in the aqueous solution increases, the microbial fermentation sometimes stops. To continuously produce microbial fermented products, it is necessary to separate the fermented product from the aqueous solution.

[0003] As an example of a method for separating an organic compound from an aqueous solution containing such a compound, the pervaporation method (total evaporation) using a pervaporation membrane can be cited. The pervaporation method is suitable for separating volatile organic compounds from aqueous solutions containing various substances. Compared to distillation, the pervaporation method tends to suppress energy consumption and carbon dioxide emissions. Patent Document 1 discloses an example of a pervaporation membrane used in the pervaporation method.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Publication No. 2005-525224 Summary of the Invention

[0005] The problem that the invention aims to solve When using a pervaporation membrane to separate an organic compound from an aqueous solution containing volatile organic compounds, improvements in separation performance are sought.

[0006] Methods for solving problems This invention provides a pervaporation membrane having a separation functional layer. The aforementioned separation functional layer has a porous layer containing pores and an epidermal layer formed on the aforementioned porous layer.

[0007] Invention Effects According to the present invention, a pervaporation membrane suitable for improving separation performance can be provided when separating an organic compound from an aqueous solution containing a volatile organic compound. Attached Figure Description

[0008] [ Figure 1 [Illustrated] is a cross-sectional view schematically showing a pervaporation membrane according to one embodiment of the present invention.

[0009] [ Figure 2[ ] is a cross-sectional view schematically illustrating another example of a pervaporation membrane according to one embodiment of the present invention.

[0010] [ Figure 3 [This is a schematic cross-sectional view of a membrane separation device equipped with a pervaporation membrane.]

[0011] [ Figure 4 [This is a perspective view schematically showing a modified example of a membrane separation device.]

[0012] [ Figure 5 [Illustration] is a schematic diagram showing an example of a membrane separation system. Detailed Implementation

[0013] The pervaporation membrane according to the first aspect of the present invention has a separation functional layer. The aforementioned separation functional layer has a porous layer containing pores and an epidermal layer formed on the aforementioned porous layer.

[0014] In a second aspect of the present invention, for example, in the pervaporation membrane involved in the first aspect, the aforementioned separation functional layer comprises a resin material.

[0015] In the third aspect of the present invention, for example, in the permeation vaporization membrane involved in the second aspect, the aforementioned resin material is an organosilicon resin.

[0016] In the fourth aspect of the present invention, for example, in the permeation vaporization membrane involved in any of the first to third aspects, the average pore size of the aforementioned pores is 1 nm or more.

[0017] In the fifth aspect of the present invention, for example, in the permeation vaporization membrane involved in any of the first to fourth aspects, the aforementioned pores form interconnected pores.

[0018] In the sixth aspect of the present invention, for example, in the permeation vaporization membrane involved in any one of the first to fifth aspects, the porosity of the aforementioned separation functional layer is 10% or more.

[0019] In the seventh aspect of the present invention, for example, the permeation vaporization membrane involved in any of the first to sixth aspects further comprises a porous support body supporting the aforementioned separation functional layer.

[0020] In the eighth aspect of the present invention, for example, in the permeation vaporization membrane involved in the seventh aspect, the aforementioned porous support is a fibrous structure.

[0021] In the ninth aspect of the present invention, for example, in the pervaporation membrane involved in any of the first to eighth aspects, the aforementioned separation functional layer includes a packing material.

[0022] In a tenth aspect of the present invention, for example, any one of the first to ninth aspects involves a pervaporation membrane used to separate the aforementioned organic compounds from an aqueous solution containing volatile organic compounds.

[0023] In the eleventh aspect of the present invention, for example, in the pervaporation membrane involved in the tenth aspect, the aforementioned organic compound is an alcohol.

[0024] In the 12th aspect of the present invention, for example, in the pervaporation membrane involved in the 11th aspect, the aforementioned alcohol is ethanol.

[0025] The present invention will now be described in detail, but this description is not intended to limit the invention to specific embodiments.

[0026] <Implementation Methods of Pervaporation Membranes> Figure 1 This is a schematic cross-sectional view illustrating a pervaporation membrane according to one embodiment of the present invention. The pervaporation membrane 10 of this embodiment includes a separation functional layer 1. The separation functional layer 1 has a porous layer 2 containing pores 4 and a skin layer 3 formed on the porous layer 2.

[0027] The pervaporation membrane of this embodiment is typically a membrane (separation membrane) that preferentially allows organic compound C to permeate from an aqueous solution S containing volatile organic compound C. The pervaporation membrane of this embodiment is suitable for improving the separation performance of organic compound C from aqueous solution S, and in particular, for increasing the flux of the permeate fluid passing through the pervaporation membrane.

[0028] (Separate functional layers) The separation functional layer 1 is, for example, a layer that allows organic compound C to preferentially permeate from the aforementioned aqueous solution S. The separation functional layer 1 has a porous layer 2 and a skin layer 3. The porous layer 2 and the skin layer 3 typically have the same composition.

[0029] The skin layer 3 is typically a dense, non-porous layer where pores cannot be identified when observed using a scanning electron microscope (SEM) at a magnification of 20,000x. It is a layer that greatly contributes to the separation performance of the permeation vaporization membrane 10. The thickness of the skin layer 3 is not particularly limited; for example, it can be 1 nm or more, 10 nm or more, 50 nm or more, 100 nm or more, or even 1 μm or more. The thickness of the skin layer 3 can be, for example, less than 30 μm, less than 20 μm, less than 10 μm, or even less than 5 μm.

[0030] The porous layer 2 supports the skin layer 3. The porous layer 2 contains pores 4. The pores 4 in the porous structure of the porous layer 2 can be independent pores, or two or more pores 4 can be connected to form interconnected pores. That is, the porous layer 2 can contain at least one element selected from the group consisting of interconnected pores and independent pores. In the porous layer 2, multiple pores 4 can be connected in a three-dimensional shape to form interconnected pores. This interconnected pore structure increases the flux of the permeate fluid passing through the permeation membrane 10.

[0031] The average pore size of pore 4 is not particularly limited; it can be greater than 1 nm or greater than 10 nm. The average pore size of pore 4 can be less than 100 μm, less than 50 μm, less than 25 μm, or less than 10 μm.

[0032] The average pore diameter of pore 4 can be determined, for example, by the following method. First, the cross-section of the separated functional layer 1 is observed using a scanning electron microscope. In the obtained electron microscope image, the pore diameters of any number (at least 20) of pores 4 are calculated, and the average of the calculated values ​​is taken as the average pore diameter.

[0033] The thickness of the porous layer 2 is not particularly limited; for example, it can be less than 500 μm, less than 300 μm, less than 200 μm, or less than 100 μm. The thickness of the porous layer 2 can be greater than 100 nm, greater than 10 μm, greater than 30 μm, or greater than 50 μm.

[0034] The thickness of the separation functional layer 1 can be, for example, less than 500 μm, less than 300 μm, less than 200 μm, less than 150 μm, or less than 110 μm. The thickness of the separation functional layer 1 can be greater than 100 nm, or greater than 1 μm, greater than 5 μm, greater than 10 μm, greater than 30 μm, or greater than 50 μm.

[0035] The porosity of the separation functional layer 1 can be 10% or more, or 20% or more. With this configuration, the flux of the permeate fluid passing through the pervaporation membrane 10 can be increased. The porosity of the separation functional layer 1 can be 90% or less, or 70% or less, 60% or less, 50% or less, or 40% or less. With this configuration, the practical strength of the pervaporation membrane 10 can be achieved.

[0036] The porosity of the separation functional layer 1 can be determined, for example, by the following method. At least five locations are observed using a scanning electron microscope to examine a cross-section of the separation functional layer 1. The magnification is set such that the entire thickness direction of the separation functional layer 1 falls within the electron microscope image. The area ratio of the pores (pores 4) in each observed location is calculated using the mathematical formula: 100 × (total area of ​​pores (pores 4)) / (area of ​​separation functional layer 1). The average of the calculated values ​​is taken as the porosity of the separation functional layer 1.

[0037] The separation functional layer 1 preferably comprises a resin material. Examples of resin materials include silicone resin, acrylic resin, phenolic resin, epoxy resin, polyolefin resin, polyurethane resin, polyimide resin, and polyamide resin.

[0038] The resin material is preferably a silicone resin. The silicone resin is, for example, formed from a silicone resin composition. There are no particular limitations on the silicone resin; it can be formed from a condensation-type silicone resin composition, an addition-type silicone resin composition, or a UV-curable silicone resin composition, but it is preferred to be formed from an addition-type silicone resin composition. Addition-type silicone resin compositions can be cured with almost no use of metals (especially tin) that promote the hydrolysis of silicone resins. Therefore, the separation functional layer 1, which contains silicone resin formed from an addition-type silicone resin composition, contains almost no metals that promote the hydrolysis of silicone resins, and tends to have high durability against the aforementioned aqueous solution S. The silicone resin can also be formed from a solvent-free silicone resin composition that is substantially free of solvents such as organic solvents.

[0039] [Addition-type silicone resin composition] Addition-type silicone resin compositions are silicone resin compositions that are cured by an addition reaction. For example, addition-type silicone resin compositions may contain polyorganosiloxane P1 having an alkenyl group and polyorganosiloxane P2 having a hydrosilane (SiH) group. Preferably, the addition-type silicone resin composition further contains a curing catalyst (hydrosilaneization catalyst). It should be noted that addition-type silicone resin compositions may also be formed by adding a curing catalyst to a commercially available silicone resin composition. However, addition-type silicone resin compositions may also be free of a curing catalyst.

[0040] In the case of addition-type silicone resin compositions, for example, a reaction (hydrosilaneation reaction) can be carried out between the alkenyl group of polyorganosiloxane P1 and the hydrosilyl group of polyorganosiloxane P2 by heat treatment to form a silicone resin. In this hydrosilaneation reaction, polyorganosiloxane P2 functions as a crosslinking agent.

[0041] Examples of alkenyl groups in polyorganosiloxane P1 include vinyl and hexenyl groups. The number of alkenyl groups in polyorganosiloxane P1 is, for example, two or more. The alkenyl groups are, for example, located at the end of the polyorganosiloxane P1.

[0042] Polyorganosiloxane P1 is, for example, a polyalkylalkylsiloxane such as polydimethylsiloxane (PDMS), polydiethylsiloxane, polymethylethylsiloxane, etc.; polyalkylarylsiloxane; poly(dimethylsiloxane-diethylsiloxane), etc., in which an alkenyl group has been introduced.

[0043] The weight-average molecular weight of polyorganosiloxane P1 is, for example, 1000 or more, but can be 10,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, or even 400,000 or more. There is a tendency that the higher the weight-average molecular weight of polyorganosiloxane P1, the better the separation characteristics of the pervaporation membrane 10. There is no specific upper limit to the weight-average molecular weight of polyorganosiloxane P1, for example, it can be 1 million.

[0044] The number of hydrosilyl groups in polyorganosiloxane P2 is, for example, 2 or more. The hydrosilyl groups can be located at the end of polyorganosiloxane P2 or contained in the main chain of polyorganosiloxane P2.

[0045] Examples of polyorganosiloxanes P2 include polymethylhydrosiloxane, poly(dimethylsiloxane-methylhydrosiloxane), and hydrosilyl-terminated polydimethylsiloxane.

[0046] The weight-average molecular weight of polyorganosiloxane P2 can be, for example, 100 or more, or even 10,000 or more. There is a tendency that the higher the weight-average molecular weight of polyorganosiloxane P2, the better the separation characteristics of the pervaporation membrane 10. There is no specific upper limit to the weight-average molecular weight of polyorganosiloxane P2, for example, it can be 1 million.

[0047] The weight ratio of polyorganosiloxane P2 to polyorganosiloxane P1, P2 / P1, is, for example, 500 wt% or less, or it can 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.

[0048] Platinum-based catalysts can be cited as examples of curing catalysts. In other words, addition-type silicone resin compositions can contain a platinum-based curing catalyst. Specific examples of platinum-based catalysts include chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes. As mentioned above, addition-type silicone resin compositions may also be free of curing catalysts.

[0049] Addition-type silicone resin compositions may contain compounds that are catalytically active species that produce a catalytic addition reaction when irradiated with active energy rays such as ultraviolet (UV). According to an addition-type silicone resin composition containing such a compound, an addition reaction can be carried out, for example, by UV irradiation.

[0050] In addition to the components mentioned above, addition-type silicone resin compositions may also contain organic solvents. 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. One organic solvent may be used alone, or two or more may be used in combination. Addition-type silicone resin compositions may also be solvent-free, substantially free of organic solvents or other solvents.

[0051] [Condensation-type silicone resin composition] Condensation-type silicone resin compositions are silicone resin compositions that are cured through a condensation reaction. Examples of condensation-type silicone resin compositions include polyorganosiloxanes P3 having silanol (SiOH) groups and silane compounds P4 having functional groups such as alkoxy, alkenoxy, acyloxy, amino, ketoxime, and amide groups. Condensation-type silicone resin compositions may or may not contain a curing catalyst. It should be noted that condensation-type silicone resin compositions can also be formed by adding a curing catalyst to commercially available silicone resin compositions.

[0052] In the case of condensation-type silicone resin compositions, for example, a condensation reaction (reaction) can be carried out between the silanol groups of polyorganosiloxane P3 and the aforementioned functional groups of silane compound P4 by heat treatment to form a silicone resin. In this condensation reaction, silane compound P4 functions as a crosslinking agent.

[0053] The number of silanol groups in polyorganosiloxane P3 is, for example, two or more. The silanol groups are, for example, located at the end of the polyorganosiloxane P3. In polyorganosiloxane P3, alkyl groups such as methyl and ethyl, phenyl, etc., can be introduced as substituents in the side chains.

[0054] Polyorganosiloxane P3 is, for example, a substance obtained by introducing silanol groups into polyorganosiloxanes described above, specifically polyorganosiloxane P1.

[0055] The weight-average molecular weight of polyorganosiloxane P3 is, for example, above 1000, but can be above 10,000, above 100,000, above 200,000, above 300,000, or even above 400,000. There is no particular upper limit to the weight-average molecular weight of polyorganosiloxane P3, for example, it can be 1 million.

[0056] As described above, silane compound P4 has functional groups such as alkoxy, alkenoxy, acyloxy, amino, ketoxime, and amide. Examples of alkoxy groups include methoxy and ethoxy. Examples of alkenoxy groups include isopropenoxy. Examples of acyloxy groups include acetoxy. Examples of amino groups include dimethylamino, diethylamino, and ethylmethylamino. Examples of ketoxime groups include acetyloxime and methylethylketoxime. Examples of amide groups include acetamido, N-methylacetamido, and N-ethylacetamido. The number of functional groups in silane compound P4 is, for example, two or more. Specifically, silane compound P4 preferably contains an alkoxysilyl group as its alkoxy group.

[0057] Silane compound P4 can be a low molecular weight compound with a molecular weight of around 1000 or less, or a high molecular weight compound with a polysiloxane backbone.

[0058] Examples of solidification catalysts include tin-based catalysts. Examples of organotin catalysts include dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin dioctanoate.

[0059] In addition to the components described above, condensation-type silicone resin compositions may also contain organic solvents. Examples of organic solvents include those described above for addition-type silicone resin compositions. Condensation-type silicone resin compositions may also be solvent-free, containing no organic solvents or other solvents.

[0060] [UV-curable silicone resin composition] UV-curable silicone resin compositions are silicone resin compositions that are cured by ultraviolet (UV) irradiation. UV-curable silicone resin compositions are cured by, for example, free radical polymerization, free radical addition, ionic polymerization, etc. UV-curable silicone resin compositions cured by free radical polymerization include, for example, a polyorganosiloxane P5 having double bonds (specifically, carbon-carbon double bonds) derived from alkenyl, acryloyl, etc. UV-curable silicone resin compositions cured by free radical addition include, for example, a polyorganosiloxane P5 having double bonds (specifically, carbon-carbon double bonds) derived from alkenyl, acryloyl, etc., and a compound P6 having functional groups such as thiol groups capable of free radical addition. UV-curable silicone resin compositions cured by ionic polymerization include, for example, a polyorganosiloxane P7 having functional groups capable of ionic polymerization such as epoxy groups, and a compound that generates catalytically active species for ionic polymerization upon UV irradiation.

[0061] According to a UV-curable silicone resin composition that undergoes a curing reaction via free radical polymerization, for example, by UV irradiation, the double bonds contained in the alkenyl, acryloyl, etc. of polyorganosiloxane P5 undergo a free radical polymerization reaction with each other, thereby forming a silicone resin.

[0062] Examples of alkenyl groups in polyorganosiloxane P5 include vinyl and hexenyl groups. The number of alkenyl groups in polyorganosiloxane P5 is, for example, two or more. The alkenyl group is, for example, located at the end of the polyorganosiloxane P5. As substituents in the side chain of polyorganosiloxane P5, alkyl groups such as methyl and ethyl, phenyl groups, etc., can be introduced.

[0063] Polyorganosiloxane P5 is, for example, a substance obtained by introducing substituents such as alkenyl or acryloyl groups with double bonds into the polyorganosiloxane described above, in relation to polyorganosiloxane P1.

[0064] The weight-average molecular weight of polyorganosiloxane P5 is, for example, above 1000, but can be above 10,000, above 100,000, above 200,000, above 300,000, or even above 400,000. There is no particular upper limit to the weight-average molecular weight of polyorganosiloxane P5, for example, it can be 1 million.

[0065] According to a UV-curable silicone resin composition that undergoes a curing reaction via free radical addition, for example, by UV irradiation, the functional groups in compound P6 capable of free radical addition undergo free radical addition to the double bonds contained in the alkenyl, acryloyl, etc., groups of polyorganosiloxane P5. This allows the free radical addition reaction to proceed, forming a silicone resin.

[0066] In compound P6, the functional groups capable of free radical addition are, for example, thiol groups and alkylthiol groups. Examples of alkylthiol groups include mercaptomethyl and mercaptoethyl groups. The number of functional groups capable of free radical addition in compound P6 is, for example, two or more.

[0067] Compound P6 can be a polyorganosiloxane containing a functional group capable of radical addition. This functional group is, for example, located at the end of the polyorganosiloxane. Substituents such as alkyl groups (e.g., methyl), ethyl groups, and phenyl groups can be introduced as substituents in the side chain of the polyorganosiloxane.

[0068] Compound P6 is, for example, a substance obtained by introducing functional groups such as thiol groups into the polyorganosiloxanes described above, which are polyorganosiloxanes.

[0069] The weight-average molecular weight of compound P6 can be above 1000, but can also be above 10,000, 100,000, 200,000, 300,000, or even above 400,000. There is no specific upper limit to the weight-average molecular weight of compound P6, for example, it can be 1 million.

[0070] According to a UV-curable silicone resin composition that undergoes a curing reaction via ion polymerization, for example, by UV irradiation, catalytically active species that catalyze ion polymerization are generated, and ion polymerization reactions occur between the functional groups contained in polyorganosiloxane P7 that are capable of ion polymerization. Thus, a silicone resin can be formed.

[0071] In polyorganosiloxane P7, the functional group capable of ion polymerization is, for example, an epoxy group. Examples of substituents containing the epoxy group include the epoxy group itself, glycidyl group, glycidyloxypropyl group, etc. The number of ion-polymerizable functional groups in polyorganosiloxane P7 is, for example, two or more. The ion-polymerizable functional group is, for example, located at the end of the polyorganosiloxane P7. As substituents in the side chain of polyorganosiloxane P7, alkyl groups such as methyl and ethyl, phenyl, etc., can be introduced.

[0072] Polyorganosiloxane P7 is, for example, a substance obtained by introducing functional groups such as epoxy groups into the polyorganosiloxanes described above for polymerization.

[0073] The weight-average molecular weight of polyorganosiloxane P7 is, for example, above 1000, but can be above 10,000, above 100,000, above 200,000, above 300,000, or even above 400,000. There is no particular upper limit to the weight-average molecular weight of polyorganosiloxane P7, for example, it can be 1 million.

[0074] In addition to the components mentioned above, UV-curable silicone resin compositions may also contain organic solvents. 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. One organic solvent may be used alone, or two or more may be used in combination. UV-curable silicone resin compositions can be solvent-free, meaning they are substantially free of organic solvents or other solvents.

[0075] The separation functional layer 1 may contain silicone resin as the main component, or it may be composed of silicone resin in essence. "Main component" refers to the component that is present in the separation functional layer 1 by weight.

[0076] The separation functional layer 1 may also include filler. For example, the separation functional layer 1 may have a matrix comprising an organosilicon resin and filler dispersed in the matrix. In this manner, all or part of the filler is embedded in the matrix in the separation functional layer 1. Within the matrix, all the filler may be separated from each other, or it may be partially aggregated.

[0077] The filler may include inorganic materials such as zeolite, silica, and bentonite. The filler may contain at least one selected from the group consisting of zeolite and silica, preferably silica. Compared to fillers containing zeolite, fillers containing silica tend to have superior hydrolysis resistance. Furthermore, using fillers containing silica tends to increase the free volume of the resin (especially organosilicon resin) contained in the matrix. If the free volume of the resin increases, the separation characteristics of the pervaporation membrane 10, especially the separation coefficient α of ethanol relative to water, tends to improve. Using fillers, the viscosity of the resin composition can be appropriately adjusted, thereby facilitating the preparation of resin compositions suitable for coating.

[0078] Silica typically refers to silicon dioxide. Fillers can be silica fillers containing silicon dioxide as the main component. Silica fillers, for example, do not have a crystalline structure. Silica fillers can be produced, for example, by reacting metallic silicon with oxygen. Silica fillers can be produced using methods such as sol-gel processes, sedimentation processes, and aqueous solution wet processes. Fillers can also consist essentially of only silicon dioxide.

[0079] However, fillers can also contain zeolites. Examples of zeolites included in fillers include high-silica zeolites with a high silica-to-alumina ratio and alumina-free silica zeolites. High-silica zeolites include HSZ (registered trademark) manufactured by Tosoh Corporation, HiSiv (registered trademark) manufactured by UNION Showa Corporation, USKY manufactured by UNION Showa Corporation, and Zeoal (registered trademark) manufactured by Nakamura Superhard Corporation.

[0080] The filler, especially the silica filler, does not have micropores with a diameter of less than 2 nm. However, the filler can also have mesopores with a diameter of 2 nm to 50 nm and macropores with a diameter of more than 50 nm.

[0081] The filler, particularly the silica filler, preferably has a surface modified with a modifying group containing a hydrocarbon group. In other words, the filler preferably undergoes surface modification based on the modifying group. Surface-modified fillers have high dispersibility in the resin and are suitable for suppressing the formation of cracks during the fabrication of the separation functional layer 1, etc.

[0082] The number of carbon atoms in the hydrocarbon group contained in the modifying group is not particularly limited, for example, it can be 1 to 25. The number of carbon atoms in the hydrocarbon group can be 5 or less. The hydrocarbon group can be any of the following: straight-chain, branched, or cyclic. Examples of hydrocarbon groups include alkyl groups such as methyl and ethyl.

[0083] The modifying group may also contain a silicon atom, to which a hydrocarbon group may be bonded. The modifying group may contain at least one selected from the group consisting of organosilicon alkyl groups and polyorganosiloxane alkyl groups. Examples of organosilicon alkyl groups include trimethylsilyl alkyl groups such as trimethylsilyl alkyl and dimethylsilyl alkyl groups such as dimethylsilyl alkyl. Examples of polyorganosiloxane alkyl groups include dimethylpolysiloxane alkyl.

[0084] Surface modification based on modifying groups can be carried out, for example, by reacting hydroxyl groups present on the filler surface with known silane coupling agents.

[0085] Specific examples of surface-modified silica fillers include the "AEROSIL (registered trademark) RX series" (RX50, RX200, RX300, etc.), "AEROSIL (registered trademark) RY series" (RY50, RY200, RY200S, etc.), "AEROSIL (registered trademark) NY series" (NY50, NY50L, etc.), "AEROSIL (registered trademark) NAX series" (NAX50, etc.), and "AEROSIL (registered trademark) R series" (R972, R974, R976, etc.) manufactured by Aerosil Corporation of Japan.

[0086] From the viewpoint of dispersibility in resin, fillers are preferably sufficiently surface-modified by modified groups. In other words, it is preferable to have a low number of hydroxyl groups on the filler surface. Whether the filler is sufficiently surface-modified by modified groups can be determined, for example, based on the pH of the filler dispersion and the Hansen solubility parameter (HSP value) of the filler. It should be noted that the Hansen solubility parameter is obtained by dividing the solubility parameter introduced by Hildebrand into three components: dispersion term δD, polar term δP, and hydrogen bonding term δH. Details of the Hansen solubility parameter are disclosed in "Hansen Solubility Parameters; A Users Handbook" (CRC Press, 2007), etc.

[0087] In this embodiment, the pH of the filler dispersion, as determined by the following tests, is, for example, 4.0 to 9.0, and can be 6.0 to 8.0. The pH of the dispersion is preferably neutral (around pH 7.0). When the pH of the dispersion is neutral, it can be said that the filler has been sufficiently surface-modified by the modifying groups, and the number of hydroxyl groups present on the surface is low.

[0088] Experiment: A dispersion was prepared by mixing water, methanol, and filler, and the pH of the dispersion was measured. Here, the filler content in the dispersion was 4 wt%, the weight ratio of water to methanol was 1:1, and the temperature of the dispersion was 25℃.

[0089] The packing material can be in the form of particles, for example. In this specification, "particle-like" includes spherical, ellipsoidal, scaly, and fibrous shapes. The packing material can also be in powder form. The average particle size of the packing material is not particularly limited; for example, it can be 50 μm or less, but can be 20 μm or less, 10 μm or less, 1 μm or less, 500 nm or less, 100 nm or less, 50 nm or less, 30 nm or less, or even 20 nm or less. Based on the above configuration, the packing material is less likely to detach from the separation functional layer 1. Furthermore, with the separation functional layer 1 containing packing material of small average particle size, the stress applied to the separation functional layer 1 is easily dispersed, tending to have high adhesion to, for example, the porous support described later. The lower limit of the average particle size of the packing material is not particularly limited; for example, it is 1 nm. The average particle size of the packing material can also be 5 nm or more, or even 10 nm or more. In this specification, average particle size refers to the primary particle size.

[0090] The average particle size of the filler can be determined, for example, by the following method. First, the cross-section of the separated functional layer 1 is observed using a transmission electron microscope. In the obtained electron microscope image, the area of ​​a specific filler is calculated by image processing. The diameter of a circle with the same area as the calculated area is taken as the particle size (particle diameter) of that specific filler. The particle sizes of any number (at least 50) of fillers are calculated, and the average of the calculated values ​​is taken as the average particle size of the filler.

[0091] The filler content in the separation functional layer 1 can be, for example, 1 wt% or more, or 5 wt% or more, 10 wt% or more, 20 wt% or more, 30 wt% or more, or even 40 wt% or more. There is no particular upper limit to the filler content in the separation functional layer 1; for example, it can be 50 wt% or less, or even 20 wt% or less. If the filler content is 50 wt% or less, it can prevent a decrease in the flux of the permeate fluid passing through the pervaporation membrane 10. Furthermore, during the fabrication of the separation functional layer 1, there is a tendency to sufficiently suppress the generation of defects such as cracks. The filler content in the separation functional layer 1 can be 1 wt% or more and 50 wt% or less, or 5 wt% or more and 20 wt% or less.

[0092] The content of the matrix in the separation functional layer 1 is not particularly limited, for example, it is 30wt%~99wt%, or it can be 30wt%~90wt%.

[0093] The surface area D1 of the filler per unit weight of matrix is ​​not particularly limited, for example, it is 5m². 2 / g or more, can be 10m 2 / g or more, 20m 2 / g or more, 30m 2 / g or more, 40m 2 / g or more, and can also be 50m 2 / g or more. There is no specific upper limit for the surface area D1, for example, 100m². 2 / g or less. Surface area D1 can be obtained based on the BET specific surface area D2 (m²) obtained by nitrogen adsorption of the packing material. 2 The weights of the matrix W1 (g) and the filler W2 (g) contained in the separation functional layer 1 are calculated according to the following formula.

[0094] D1(m) 2 / g)=D2(m 2 / g)×W2(g) / W1(g) (Porous support) like Figure 2 As shown, the pervaporation membrane of this embodiment preferably further comprises a porous support 5. The porous support 5 supports the separation functional layer 1. Figure 2 In the pervaporation membrane 20 shown, the surface of the porous layer 2 in the separation functional layer 1 is directly in contact with the porous support 5, and the surface of the skin layer 3 constitutes the surface of the pervaporation membrane 20.

[0095] The pervaporation membrane 20 in this embodiment is composed of, for example, only a separation functional layer 1 and a porous support 5.

[0096] In this embodiment, the porous support 5 may also have only a main body without a microporous layer. The porous support 5 is preferably a fibrous structure. Examples of fibrous structures include woven fabrics, nonwoven fabrics, and stretched porous membranes containing fibrils. Typically, the fibrous structure is a nonwoven fabric or a stretched porous membrane. According to the above method, the flux of the permeate fluid passing through the pervaporation membrane 20 can be increased.

[0097] When the fibrous structure is a woven or nonwoven fabric, the fibers contained within the fibrous structure can be, for example, natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. The porous support 5 is, for example, a nonwoven fabric made of polyester fibers. Examples of nonwoven fabrics include polyethylene terephthalate (PET) nonwoven fabric and polyphenylene sulfide (PPS) nonwoven fabric.

[0098] When the fibrous structure is a stretched porous membrane, the fibrous structure preferably contains a fluoropolymer. Examples of fluoropolymers include polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluoropolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP), with PTFE being the most preferred.

[0099] As an example, PTFE stretched porous membranes are formed by stretching a paste extruder or cast film containing PTFE particles. PTFE stretched porous membranes are composed of fine PTFE fibrils, and compared to the fibrils, they also have nodes in a state of PTFE aggregation.

[0100] The porous support 5 (main body) has an average pore size of, for example, 1 μm to 50 μm.

[0101] Depending on the circumstances, the porous support 5 may have a main body and a microporous layer disposed on the main body. In the pervaporation membrane 10, the microporous layer is located between the main body of the porous support 5 and the separation functional layer 1.

[0102] Examples of materials that can be used as microporous layers include fluoropolymers such as polyvinylidene fluoride and polytetrafluoroethylene; polyaryl ether sulfones such as polysulfone and polyether sulfone; and polyimide. The microporous layers have an average pore size of, for example, 0.01 μm to 0.4 μm.

[0103] The thickness of the porous support 5 is not particularly limited; for example, it can be 10 μm or more, 50 μm or more, or 100 μm or more. The thickness of the porous support 5 can be, for example, 300 μm or less, or 200 μm or less.

[0104] In this embodiment, the separation functional layer 1 is directly connected to the fibrous structure (specifically, a nonwoven fabric). When the porous support 5 comprises a main body and a microporous layer, the separation functional layer 1 is directly connected to the microporous layer.

[0105] The surface of the porous support 5, which is in contact with the separation functional layer 1, can be treated for easy adhesion. Examples of easy adhesion treatments include surface treatments such as corona discharge treatment and plasma treatment.

[0106] Alternatively, the easy-bonding treatment can be a coating treatment based on a molecular bonding agent. The molecular bonding agent comprises a molecular bonding compound (hereinafter referred to as "Compound C1") and a solvent such as an organic solvent or water, used as needed. Compound C1 has a reactive group F1 that can react with the surface of the porous support 5 and a reactive group F2 that can react with the resin (especially silicone resin) contained in the separation functional layer 1. The reactive group F2 can react not only with the silicone resin but also with the surface of the porous support 5.

[0107] The reactive group F1 is, for example, at least one selected from the group consisting of amino, azide, mercapto, isocyanate, urea, and epoxy groups, typically azide. The reactive group F2 is, for example, at least one selected from the group consisting of silanol and a group G that can be hydrolyzed to form a silanol. A specific example of group G is alkoxysilyl.

[0108] Compound C1 is represented, for example, by the following formula (1).

[0109] R A -ZR B (1) In equation (1), R A R represents a reactive group F1 or a monovalent substituent having one or more reactive groups F1. B F2 represents the reactive group, and Z represents a divalent organic group.

[0110] In formula (1), Z can be an alkylene group having 1 to 20 carbon atoms that may have a substituent, an alkenyl group having 2 to 20 carbon atoms that may have a substituent, an alkynyl group having 2 to 20 carbon atoms that may have a substituent, or an aryl group having 6 to 20 carbon atoms that may have a substituent.

[0111] Examples of alkylene groups having 1 to 20 carbon atoms include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene, with methylene, ethylene, and propylene being preferred, and propylene being more preferred. Examples of alkenylene groups having 2 to 20 carbon atoms include vinylene, propenylene, butenylene, and pentenylene. Examples of yntynylene groups having 2 to 20 carbon atoms include ethynylene and propynylene. Examples of arylene groups having 6 to 20 carbon atoms include o-phenylene, m-phenylene, p-phenylene, 2,6-naphthylene, and 1,5-naphthylene.

[0112] Substituents that may be present in the aforementioned alkylene, alkenylene, and alkyne groups include, for example, halogen atoms such as fluorine and chlorine atoms; alkoxy groups such as methoxy and ethoxy; alkylthio groups such as methylthio and ethylthio; and alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl.

[0113] Examples of substituents that may be present in the aforementioned arylene group include cyano; nitro; halogen atoms such as fluorine, chlorine, and bromine atoms; alkyl groups such as methyl and ethyl; alkoxy groups such as methoxy and ethoxy; and alkyl thio groups such as methylthio and ethylthio.

[0114] The aforementioned substituents can be bonded to any position in alkylene, alkenylene, ynylene, and aryl groups, and multiple substituents can be bonded to the same element or different elements.

[0115] As R A For example, the groups represented by the following formulas (2) to (4) can be cited.

[0116] [Chemical Formula 1] In equations (2) to (4), R represents the connection bond with Z in equation (1).1 R represents a divalent hydrocarbon group with 1 to 10 carbon atoms. 2 and R 3 Each can independently represent a hydrocarbon group with 1 to 20 hydrogen or carbon atoms. R 4 and R 5 Each can independently represent the reactive group F1 or the group represented by formula (2) above. It should be noted that R... 4 and R 5 In the case where the group is represented by formula (2), in formula (2), R represents the bond connecting the carbon atom that forms the triazine ring in equation (4). 6 Indicates a single bond or -N (R) 7 )- represents a divalent group. R 7 A hydrocarbon group representing 1 to 20 hydrogen or carbon atoms.

[0117] In equation (2), R is used as 1 Preferably, a divalent hydrocarbon group with 2 to 6 carbon atoms is used. As R 1 Examples include alkylene or aryl groups having 1 to 10 carbon atoms; specifically, alkylene groups such as ethylene and trimethylene; and aryl groups such as o-phenylene, m-phenylene, and p-phenylene.

[0118] In equation (2), R 2 and R 3 Each is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. As R 2 and R 3 Examples of alkyl, alkynyl, or aryl groups with 1 to 20 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl alkyl groups; vinyl, 1-propenyl, 2-propenyl, isopropenyl, 3-butenyl, 4-pentenyl, and 5-hexenyl alkenyl groups; ethynyl, propynyl, and butynyl alkenyl groups; and phenyl, 1-naphthyl, and 2-naphthyl aryl groups.

[0119] In equation (4), R 4 and R 5 Preferably, the reactive groups F1 are the same as each other.

[0120] In equation (4), R 6 Indicates a single bond or -N (R) 7 )- represents a divalent group. As R 7 Hydrocarbon groups, such as those used as R in the above example, can be cited. 2 and R 3 The same group as the hydrocarbon group described above. R 6 The preferred expression is -NH-.

[0121] R A Preferably, it is the group represented by formula (4) among the groups represented by formulas (2) to (4) above, more preferably the group represented by formula (4), and R 4 Or R 5 It is an azide group or a group represented by the above formula (2).

[0122] As R A For example, the group represented by the following formula (5) can be cited.

[0123] [Chemical Formula 2] In equation (5), R represents the connection bond with Z in equation (1). 1 ~R 3 and R 6 Each is identical to the groups described above for formulas (2) and (4). R 1 ~R 3 They can be the same or different.

[0124] In equation (1), R B It can be a group represented by the following formula (6).

[0125] -Si(X) a (Y) 3-a (6) In formula (6), X represents a hydroxyl group or an alkoxy group with 1 to 10 carbon atoms, and Y represents a hydrocarbon group with 1 to 20 carbon atoms. a represents an integer from 1 to 3.

[0126] In formula (6), X can be, for example, methoxy, ethoxy, n-propoxy, isopropoxy, etc., with ethoxy being preferred. Y can be, for example, R in formula (2). 2 and R 3 The hydrocarbon group is one of the groups described above.

[0127] R B Preferably, X represents a hydroxyl group or an alkoxy group having 1 to 10 carbon atoms, and a is a group of 3. More preferably, X represents a hydroxyl group or an ethoxy group, and a is a group of 3.

[0128] As R A Compounds with an amino group at C1 include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, [3-(phenylamino)propyl]trimethoxysilane, trimethyl[3-(triethoxysilyl)propyl]ammonium chloride, and trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride.

[0129] As R A Compounds with an azide group (C1) include (11-azidoundecyl)trimethoxysilane and (11-azidoundecyl)triethoxysilane.

[0130] As R A Examples of compounds with a thiol group (C1) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane.

[0131] As R A Compounds with an isocyanate group (C1) include 3-(trimethoxysilyl)propyl isocyanate and 3-(triethoxysilyl)propyl isocyanate.

[0132] As R A Compounds with a urea group at C1 include 3-ureopropyltrimethoxysilane and 3-ureopropyltriethoxysilane.

[0133] As R A Compounds with an epoxy group at C1 include 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, and 3-epoxypropoxypropylmethyldiethoxysilane.

[0134] As R A Compound C1 is a monovalent substituent having one or more reactive groups F1, for example, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and compounds represented by the following formulas (1-1) to (1-9).

[0135] [Chemical Formula 3] [Chemical Formula 4] (1-1): N,N'-bis(2-aminoethyl)-6-(3-trihydroxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-2): N,N'-bis(2-aminoethyl)-6-(3-trimethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-3): N,N'-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-4): N,N'-bis(2-aminomethyl)-6-(3-trihydroxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-5): N,N'-bis(2-aminomethyl)-6-(3-trimethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-6): N,N'-bis(2-aminomethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (1-7): 6-(3-trihydroxysilylpropyl)amino-1,3,5-triazine-2,4-diazidide (1-8): 6-(3-trimethoxysilylpropyl)amino-1,3,5-triazine-2,4-diazide (1-9): 6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diazidide Compound C1 is preferably a compound represented by formulas (1-1) to (1-9) above, and more preferably a compound represented by formula (1-1) or a compound represented by formula (1-9).

[0136] The pervaporation membrane 20 may also include an intermediate layer disposed between the separation functional layer 1 and the porous support 5. The intermediate layer is typically formed from an adhesive composition. The adhesive composition may be a composition comprising a silicone-based polymer (silicone adhesive).

[0137] The permeation vaporization membrane involved in this embodiment may also not have a porous support 5.

[0138] (Manufacturing method of pervaporation membrane) The pervaporation membrane 10 can be manufactured, for example, by the following method. First, a coating liquid L is prepared, which includes at least a material comprising the separation functional layer 1 and a dispersion or foaming agent dispersed in the material as a dispersion medium. The dispersion is, for example, water or a hydrophilic compound. After coating the coating liquid L to form a coating film, the coating film is cured. By removing the dispersion from the coating film or foaming the foaming agent, the separation functional layer 1 can be obtained.

[0139] The material of the aforementioned separation functional layer 1 is typically an organosilicon resin composition.

[0140] The proportion of the silicone resin composition in coating liquid L can be 20 wt% or more, 30 wt% or more, or 40 wt% or more. The proportion of the silicone resin composition in coating liquid L can be less than 70 wt%, 60 wt% or less, or 50 wt% or less.

[0141] In a preferred embodiment of the method for manufacturing the pervaporation membrane according to this embodiment, the coating liquid L contains water as a dispersion. The coating liquid L is, for example, an emulsion formed by dispersing water in an organosilicon resin composition.

[0142] The coating liquid L may also contain additives. The additives are preferably inorganic tackifiers and surfactants.

[0143] Inorganic thickeners are formulated to increase the viscosity of water, facilitate its dispersion in silicone resin compositions, and stabilize the dispersion. Examples of inorganic thickeners include natural or synthetic smectite clays such as bentonite, montmorillonite, lithium montmorillonite, smectite, zinc montmorillonite, bedesulfurite, and natronite; magnesium aluminum silicate; and complexes thereof with water-soluble organic polymers such as carboxyvinyl polymers, with bentonite and montmorillonite clays being preferred. Commercially available smectite clays include, for example, Smecton SA (manufactured by KUNIMINE INDUSTRIES CO., LTD.) as a hydrothermal synthesized product and BEN-GEL (manufactured by HOJUN Co., Ltd.) as a natural refined product. The content of the inorganic thickener relative to 100 parts by weight of water is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight.

[0144] The total mass ratio of water and inorganic tackifier in coating solution L can be 30 wt% or more, 40 wt% or more, or 50 wt% or more. The total mass ratio of water and inorganic tackifier in coating solution L can be less than 80 wt%, 70 wt% or less, or 60 wt% or less.

[0145] Surfactants typically include nonionic surfactants. Examples of surfactants include glycerol fatty acid esters, polyglycerol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, polyoxyethylene glycerol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene-polyoxypropylene block copolymers, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene fatty acid amides.

[0146] The surfactant is preferably composed only of nonionic surfactants. Based on this composition, water can be well dispersed in the silicone resin composition, and a separation functional layer 1 with uniform and fine interconnected pores can be formed. The coating liquid L may contain two or more surfactants, and may contain two or more nonionic surfactants.

[0147] The proportion of the surfactant in the coating liquid L relative to the silicone resin composition can be 0.1 wt% or more and 15 wt% or less, or 0.2 wt% or more and 3 wt% or less.

[0148] For example, coating liquid L is prepared by emulsifying dispersion water (formed by dispersing an inorganic tackifier in water), the material of separation functional layer 1 (specifically, an organosilicon resin composition), and a surfactant. Coating liquid L is applied to substrate A to form a coating film. Then, substrate B is placed on the surface of the coating film opposite to substrate A. The coating film is then cured (pre-cured). After removing one substrate (e.g., substrate B), the coating film is further cured (formal cured), for example, by heating and drying, and the aforementioned dispersion is removed from the coating film. Then, another substrate (e.g., substrate A) is removed, thereby obtaining separation functional layer 1. Separation functional layer 1 produced by the above method typically has openings on the side surface of the porous layer 2, and pores 4 form connecting holes. These connecting holes typically communicate with the openings.

[0149] Pre-curing of the coated film can be carried out at room temperature or under heating conditions. Pre-curing of the coated film can also be carried out by irradiation with active energy rays such as UV rays.

[0150] In cases where the coating film is cured by heating, the heating conditions for pre-curing are not particularly limited. For example, the heating temperature of the coating film can be above 50°C, or above 60°C, above 70°C, or above 80°C. The upper limit of the heating temperature of the coating film in pre-curing is, for example, 110°C.

[0151] By further heating and drying after removing either substrate A or B, water evaporates from the coated film, and the resin composition within the coated film is fully cured. The heating temperature at this time can be, for example, above 100°C, above 120°C, above 130°C, or above 150°C. The higher the heating temperature of the coated film, the more complete the curing reaction of the components in the resin composition. There is no particular upper limit to the heating and drying temperature of the coated film, for example, 250°C. The heating and drying time can be appropriately adjusted according to the composition of the resin composition used.

[0152] Substrates A and B are, for example, release liner. Examples of release liners include resin-containing films; paper; sheets containing metal materials such as aluminum and stainless steel. Sheets containing metal materials tend to have high heat resistance. From the perspective of excellent surface smoothness, resin-containing films are preferred as release liners. Examples of polymers contained in the resin in the release liner include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, and polymethylpentene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyvinyl chloride and vinyl chloride copolymers; polyurethane; and ethylene-vinyl acetate copolymers, with polyesters being preferred, and polyethylene terephthalate being particularly preferred.

[0153] A release treatment can be applied to the surface of the release liner. This release treatment can be performed, for example, by applying a release agent to the surface of the release liner. Examples of release agents include silicone-based release agents, long-chain alkyl-based release agents, fluorinated release agents, and molybdenum sulfide-based release agents. The release agent can be used alone or in combination of two or more. The release liner is preferably a polyethylene terephthalate (PET) film that has undergone the release treatment.

[0154] The thickness of the release liner is not particularly limited, for example, it is 5 to 100 μm, preferably 10 to 50 μm.

[0155] In another preferred embodiment of the method for manufacturing the pervaporation membrane according to this embodiment, the coating liquid L contains a hydrophilic compound as a dispersion. The hydrophilic compound is, for example, a polyether or a polyol, preferably polyethylene glycol (PEG) or glycerol. In this case, the coating liquid L may not contain inorganic thickeners or surfactants.

[0156] For example, a coating solution L containing PEG or glycerol dispersed in a material of the separating functional layer 1 (specifically, an organosilicon resin composition) is coated onto a substrate A to form a coating film. Then, a substrate B is placed on the surface of the coating film opposite to that of substrate A. Afterward, the coating film is cured, and the coating film after removing one substrate is washed to remove the PEG or glycerol. At this point, one substrate can be removed after pre-curing, followed by further formal curing and then washing; alternatively, one substrate can be removed and washed after consecutive pre-curing and formal curing. Washing can be performed, for example, by immersion in a water bath. The separating functional layer 1 can be obtained in this manner. After washing, the coating film can be dried. The separating functional layer 1 produced by the above method typically has openings on the surface of the porous layer 2 side, and the holes 4 form interconnecting pores. These interconnecting pores typically communicate with the openings.

[0157] In another embodiment of the method for manufacturing the pervaporation membrane, the coating liquid L includes a foaming agent. For example, the coating liquid L is prepared by mixing an organosilicon resin composition and a foaming agent. After coating the coating liquid L onto a substrate A to form a coating film, the coating film is cured and foamed by heating it. Then, by removing the substrate A, a pervaporation membrane 10 including a separation functional layer 1 is obtained. Any suitable foaming agent can be used as the foaming agent. Sodium bicarbonate or 4,4'-oxobis(benzenesulfonyl)hydrazine (OBSH) is preferred. In the separation functional layer 1 prepared by the above method, the pores 4 of the porous layer 2 are typically independent pores.

[0158] By operating in the above manner, a pervaporation membrane 10 containing a separation functional layer 1 can be produced.

[0159] The pervaporation membrane 20, which also includes a porous support 5, can be manufactured, for example, by laminating a separation functional layer 1 obtained using the manufacturing method of the pervaporation membrane 10 described above onto the porous support 5. Alternatively, the separation functional layer 1 can be laminated onto the surface of the porous support 5, which has undergone an easy-to-bond treatment.

[0160] Before stacking the separation functional layer 1 with the porous support 5, the surface of the separation functional layer 1 can be subjected to a surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, excimer laser treatment, and flame treatment, with corona treatment being preferred. Surface modification treatment can be performed, for example, by irradiating the surface of the separation functional layer 1 with active energy rays. Specific examples of active energy rays include electron beams, ion beams, plasma beams, and ultraviolet light.

[0161] The method for manufacturing the pervaporation membrane 20 is not limited to the above method. For example, in the manufacturing of the pervaporation membrane 10, a separation functional layer 1 can be formed on the porous support 5 as the substrate A, thereby manufacturing a pervaporation membrane 20 having a porous support 5.

[0162] (Applications of pervaporation membranes) Unless otherwise specified, the matters described below regarding the pervaporation membrane 10 also apply to the pervaporation membrane 20. The pervaporation membrane 10 of this embodiment is suitable, for example, for separating organic compound C from an aqueous solution S containing a volatile organic compound C. There is no particular limitation as long as the organic compound C is volatile. In this specification, "volatile organic compound" refers to, for example, an organic compound with a boiling point of 20°C to 260°C at atmospheric pressure (101.325 kPa). It should be noted that, for example, when the concentration of organic compound C in the aqueous solution is high, an aqueous phase containing water as the main component and an organic phase in which the content of organic compound C is higher than that of the aqueous phase are produced. However, organic compound C may also not produce an aqueous phase or an organic phase.

[0163] There is no particular limitation on the number of carbon atoms in organic compound C; for example, it can be less than 10, less than 8, less than 6, or even less than 4. The lower limit for the number of carbon atoms in organic compound C can be 1 or 2. Organic compound C may have functional groups containing oxygen atoms, such as hydroxyl, carbonyl, ether, or ester groups. Typically, organic compound C contains only one oxygen-containing functional group.

[0164] Examples of organic compound C include alcohols, ketones, and esters, with alcohols being typical. Alcohols can be alkyl alcohols consisting only of alkyl groups and hydroxyl groups, or aryl alcohols containing aryl groups and hydroxyl groups. Alkyl alcohols can be linear, branched, or cyclic. Examples of alkyl alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, isobutanol, tert-butanol, and n-pentanol, with ethanol, isopropanol, and n-butanol being preferred, and ethanol being more preferred. Examples of aryl alcohols include phenol.

[0165] Ketones can be dialkyl ketones consisting only of alkyl and carbonyl groups. Examples of dialkyl ketones include methyl ethyl ketone (MEK) and acetone.

[0166] Esters can be fatty acid alkyl esters consisting only of alkyl groups and ester groups. Examples of fatty acid alkyl esters include ethyl acetate.

[0167] It should be noted that organic compound C is not limited to the compounds mentioned above. Organic compound C can be aromatic hydrocarbons such as benzene, toluene, and xylene, or amide solvents such as N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP).

[0168] The aqueous solution S may contain one or more organic compounds C. The content of organic compound C in the aqueous solution S may be, for example, 0.5 wt% or more, 1 wt% or more, 2 wt% or more, or 5 wt% or more. There is no particular upper limit to the content of organic compound C, for example, 50 wt%.

[0169] Organic compound C can be a fermentation product produced by microorganisms fermenting a carbon source, or it can be an alcohol (bio-alcohol) produced by microorganisms. That is, the aqueous solution S can be a fermentation broth containing organic compound C as a fermentation product. However, the aqueous solution S is not limited to fermentation broth, and can also be waste liquid or wastewater discharged from chemical equipment, etc.

[0170] Besides water and organic compounds C, the aqueous solution S may also contain other components such as microorganisms that produce fermentation products, carbon sources, nitrogen sources, and inorganic ions. The microorganisms that produce fermentation products are typically bacteria. Examples of carbon sources include polysaccharides such as starch and monosaccharides such as glucose.

[0171] (Characteristics of pervaporation membrane) In the pervaporation membrane 10, the separation coefficient of organic compound C relative to water is not particularly limited. As an example, the separation coefficient α of ethanol (EtOH) relative to water in the pervaporation membrane 10 is... EtOH For example, it can be 5 or higher, or it can be 6 or higher, 7 or higher, or even 8 or higher. Separation coefficient α EtOH The upper limit is, for example, 100.

[0172] Separation coefficient α EtOH The following method can be used to determine the separation coefficient. With a mixed liquid containing EtOH and water in contact with the main surface of the skin layer 3 side of the separation functional layer 1 of the pervaporation membrane 10, the space adjacent to the other main surface of the pervaporation membrane 10 (the surface on the porous layer 2 side of the separation functional layer 1, or the main surface on the porous support 5 side in the case of the pervaporation membrane 20) is depressurized. This yields the permeate fluid that passes through the pervaporation membrane 10. The weight ratio of water and the weight ratio of EtOH in the permeate fluid are measured. In the above operation, the EtOH content in the mixed liquid is 2.0 wt%. The temperature of the mixed liquid in contact with the pervaporation membrane 10 is 40°C. The space adjacent to the other side of the pervaporation membrane 10 is depressurized to 15 hPa. EtOH It can be calculated using the following formula. Where, in the following formula, X... A and X B These represent the weight ratios of EtOH and water in the mixed liquid, respectively. A and Y B These represent the weight ratios of EtOH and water in the permeate fluid passing through the pervaporation membrane 10, respectively.

[0173] Separation coefficient α EtOH =(Y A / Y B ) / (X A / X B ) The above separation coefficient α EtOH In the measurement conditions, the flux of EtOH permeating through the pervaporation membrane 10 is not particularly limited, for example, it can be 0.001 kg / m³. 2 Above / hr, it can also be 0.010kg / m 2 / hr or more, 0.020kg / m 2 Above / hr, it can also be 0.050kg / m 2 / hr or more. The flux of EtOH permeating from the pervaporation membrane 10 can be 1.0 kg / m³. 2 Below / hr, it can also be 0.8kg / m 2Below / hr, it can also be 0.6kg / m 2 / hr or less.

[0174] The separation coefficient α of isopropanol (IPA) relative to water in pervaporation membrane 10 IPA For example, a value of 5 or higher can be 6 or higher, 7 or higher, 8 or higher, or even 9 or higher. Separation coefficient α IPA The upper limit is, for example, 100.

[0175] Besides using a mixture of IPA and water at a concentration of 10 wt% to replace the mixture containing EtOH and water, it is possible to utilize the separation coefficient α EtOH The separation coefficient α was determined using the same method. IPA .

[0176] The separation coefficient α of n-butanol (BuOH) relative to water in pervaporation membrane 10 BuOH For example, it can be 8 or higher, or it can be 10 or higher, 12 or higher, or even 14 or higher. Separation coefficient α BuOH The upper limit is, for example, 100.

[0177] Instead of a mixture containing EtOH and water, a mixture containing BuOH at a concentration of 0.8 wt% is used, and the temperature of the mixture is 30°C. Furthermore, the separation coefficient α can be utilized. EtOH The separation coefficient α was determined using the same method. BuOH .

[0178] In the pervaporation membrane 10 of this embodiment, the separation functional layer 1 has a porous layer 2 and a skin layer 3, thereby tending to have good separation performance (especially the flux of the permeate fluid passing through the pervaporation membrane).

[0179] <Implementation Methods of Membrane Separation Devices> like Figure 3 As shown, the membrane separation apparatus 100 of this embodiment includes a pervaporation membrane 20 and a tank 23. In the membrane separation apparatus 100, a pervaporation membrane 10 may also be used instead of the pervaporation membrane 20. The tank 23 has a first chamber 21 and a second chamber 22. The first chamber 21 functions as a supply space for supplying a supply fluid (specifically, the aforementioned aqueous solution S). The second chamber 22 functions as a permeation space for supplying a permeate fluid S1. The permeate fluid S1 can be obtained by permeating the aqueous solution S through the pervaporation membrane 20.

[0180] A pervaporation membrane 20 is disposed inside the tank 23. Inside the tank 23, the pervaporation membrane 20 separates the first chamber 21 and the second chamber 22. The pervaporation membrane 20 extends from one of a pair of walls of the tank 23 to the other.

[0181] The first chamber 21 has an inlet 21a and an outlet 21b. The second chamber 22 has an outlet 22a. The inlet 21a is an opening for supplying the aqueous solution S to the supply space (the first chamber 21). The outlet 22a is an opening for discharging the permeate fluid S1 from the permeate space (the second chamber 22). The outlet 21b is an opening for discharging the aqueous solution S (non-permeate fluid S2) that has not permeated through the pervaporation membrane 20 from the supply space (the first chamber 21). The inlet 21a, outlet 21b, and outlet 22a are each formed, for example, on the wall of the tank 23.

[0182] The membrane separation device 100 is suitable for flow-through (continuous) membrane separation methods. However, the membrane separation device 100 can also be used for intermittent membrane separation methods.

[0183] (Operation method of membrane separation device) The membrane separation device 100 is operated as follows. First, an aqueous solution S is supplied to the first chamber 21 of the membrane separation device 100 through inlet 21a. This allows the aqueous solution S to come into contact with one side of the pervaporation membrane 20 (for example, the main surface on the porous layer 2 side of the separation functional layer 1).

[0184] Next, with the aqueous solution S in contact with one side of the pervaporation membrane 20, the space adjacent to the other side of the pervaporation membrane 20 (e.g., the main surface of the porous support 5) is depressurized. Specifically, depressurization is performed in the second chamber 22 through outlet 22a. Depressurization in the second chamber 22 can be performed, for example, by a depressurization device such as a vacuum pump. The pressure in the second chamber 22 can be, for example, 50 kPa or less, but can be 20 kPa or less, 10 kPa or less, 5 kPa or less, 3 kPa or less, or even 2 kPa or less. It should be noted that, unless otherwise specified, "pressure" in this specification refers to absolute pressure.

[0185] By depressurizing the second chamber 22, a permeate fluid S1 with a high content of organic compound C can be obtained on the other side of the pervaporation membrane 20. In other words, the permeate fluid S1 is supplied to the second chamber 22. Inside the second chamber 22, the permeate fluid S1 is typically a gas. The permeate fluid S1 is discharged to the outside of the membrane separation device 100 through the outlet 22a.

[0186] On the other hand, the content of organic compound C in the aqueous solution S decreases slowly from the inlet 21a of the first chamber 21 to the outlet 21b. The aqueous solution S (non-permeable fluid S2) treated in the first chamber 21 is discharged to the outside of the membrane separation device 100 through the outlet 21b. The non-permeable fluid S2 is typically a liquid.

[0187] As described above, the pervaporation membrane 20 preferentially allows organic compounds C contained in the aqueous solution S to permeate. Therefore, the permeate fluid S1 obtained through the operation of the membrane separation device 100 has a higher content of organic compounds C than the aqueous solution S supplied to the membrane separation device 100.

[0188] <Modifications of Membrane Separation Devices> The membrane separation device 100 can be a spiral membrane element, a hollow fiber membrane element, a coil-type membrane element with multiple pervaporation membranes stacked, a plate and frame type membrane element, etc. Figure 4 A spiral-shaped membrane element is shown. Figure 4 The membrane separation device 110 includes a central tube 26 and a laminate 27. The laminate 27 includes a pervaporation membrane 20. In the membrane separation device 110, a pervaporation membrane 10 may also be used instead of the pervaporation membrane 20.

[0189] The central tube 26 has a cylindrical shape. Multiple holes or slits are formed on the surface of the central tube 26 to allow the permeable fluid S1 to flow into the interior of the central tube 26. Examples of materials for the central tube 26 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 26 is, for example, in the range of 20 to 100 mm.

[0190] In addition to the pervaporation membrane 20, the laminate 27 also includes a supply-side flow path material 28 and a permeation-side flow path material 29. The laminate 27 is wound around the central tube 26. The membrane separation device 110 may also include an external material (not shown).

[0191] As the supply-side flow path material 28 and the through-side flow path material 29, nets, woven fabrics or knitted fabrics made of resins such as polyethylene, polypropylene, polyethylene terephthalate (PET), polyphenylene sulfide (PPS) or ethylene-chlorotrifluoroethylene copolymer (ECTFE) can be used.

[0192] The membrane separation device 110 can be operated, for example, by the following method: First, an aqueous solution S is supplied to one end of the wound laminate 27. The internal space of the central tube 26 is depressurized. As a result, the permeate fluid S1 that has passed through the pervaporation membrane 20 of the laminate 27 moves into the interior of the central tube 26. The permeate fluid S1 passes through the central tube 26 and is discharged to the outside. The aqueous solution S (non-permeate fluid S2) treated in the membrane separation device 110 is discharged to the outside from the other end of the wound laminate 27.

[0193] <Implementation Methods of Membrane Separation Systems> like Figure 5As shown, the membrane separation system 200 of this embodiment includes the membrane separation apparatus 100 described above. It should be noted that the membrane separation system 200 may also include... Figure 4 The membrane separation device 110 described herein is used instead of the membrane separation device 100.

[0194] The membrane separation system 200 includes a membrane separation unit 100 and a tank 30. The tank 30 stores an aqueous solution S to be supplied to the membrane separation unit 100. The tank 30 may also be a fermentation tank used to generate organic compound C by fermentation using a microbial-based carbon source.

[0195] The membrane separation system 200 also includes an aqueous solution supply path 70, a non-permeable fluid discharge path 71, and a permeable fluid discharge path 72. The aqueous solution supply path 70 is used to supply aqueous solution S from tank 30 to membrane separation unit 100 during operation, and is connected to the outlet 31 of tank 30 and the inlet 21a of membrane separation unit 100. For example, a pump 50 for controlling the flow rate of aqueous solution S is installed in the aqueous solution supply path 70.

[0196] The non-permeable fluid discharge path 71 is a path for discharging the non-permeable fluid S2 from the membrane separation unit 100 during operation, and is connected to the outlet 21b of the membrane separation unit 100. For example, a pump 51 for controlling the flow rate of the non-permeable fluid S2 is installed in the non-permeable fluid discharge path 71. It should be noted that the pump 51 may not be installed in the non-permeable fluid discharge path 71. The non-permeable fluid discharge path 71 may also be connected to the inlet 32 ​​of the tank 30 and configured to supply the non-permeable fluid S2 to the tank 30 during operation. That is, it may also be configured such that the non-permeable fluid S2 is mixed with the aqueous solution S in the tank 30 during operation and circulates in the aqueous solution supply path 70 and the non-permeable fluid discharge path 71. When the non-permeable fluid S2 is supplied to the tank 30, the aqueous solution S and the non-permeable fluid S2 are mixed within the tank 30, and the content of organic compound C in the aqueous solution S decreases. When tank 30 is a fermentation tank, the cessation of microbial-based fermentation can be inhibited by reducing the content of organic compound C in aqueous solution S, thereby enabling continuous production of fermented products.

[0197] The permeate discharge path 72 is a path for discharging the permeate fluid S1 from the membrane separation unit 100 during operation, and is connected to the outlet 22a of the membrane separation unit 100. A pressure reducing device 52 is provided in the permeate discharge path 72, for example. The pressure reducing device 52 can reduce the pressure within the permeate space of the membrane separation unit 100. The pressure reducing device 52 is preferably a vacuum device such as a vacuum pump. The vacuum pump is typically a gas-transporting vacuum pump, and examples include reciprocating vacuum pumps and rotary vacuum pumps. Examples of reciprocating vacuum pumps include diaphragm type and oscillating piston type vacuum pumps. Examples of rotary vacuum pumps include: liquid-sealed pumps; oil rotary pumps (rotary pumps); mechanical booster pumps; and various dry pumps such as Roots type, claw type, screw type, turbine type, and scroll type. The pump serving as the pressure reducing device 52 may also have a variable speed mechanism for changing the rotational speed, etc. An example of a variable speed mechanism is an inverter that drives the pump's motor. By using a variable speed mechanism to control the pump speed, the pressure of the permeation space of the membrane separation device 100 can be appropriately adjusted.

[0198] A heat exchanger for cooling the permeate fluid S1 can also be configured in the permeate discharge path 72. The heat exchanger allows the gaseous permeate fluid S1 to condense. The heat exchanger is, for example, a gas-liquid heat exchanger that generates heat exchange between a cooling medium such as antifreeze and the gaseous permeate fluid S1. The heat exchanger can be located between the membrane separation unit 100 and the pressure reducing unit 52 (upstream of the pressure reducing unit 52), or between the pressure reducing unit 52 and the recovery unit 40 (described later) (downstream of the pressure reducing unit 52).

[0199] The membrane separation system 200 also includes a recovery unit 40. The recovery unit 40 recovers the permeate fluid S1 from the membrane separation unit 100, and can, for example, store the permeate fluid S1. The recovery unit 40 is, for example, a tank for storing the permeate fluid S1. A permeate fluid discharge path 72 is connected to the inlet 41 of the recovery unit 40.

[0200] The membrane separation system 200 may also include a controller 60 for controlling the various components of the membrane separation system 200. The controller 60 may be, for example, a DSP (Digital Signal Processor) including an A / D conversion circuit, input / output circuit, arithmetic circuit, and storage device. The controller 60 stores a program for properly operating the membrane separation system 200.

[0201] Unless otherwise specified, the various paths of the membrane separation system 200 are, for example, made of metal or resin piping.

[0202] Example The present invention will now be described in more detail through examples and comparative examples, but the present invention is not limited thereto.

[0203] <Preparation of the pervaporation membrane> (Example 1) First, a montmorillonite dispersion was prepared by dispersing 0.9% by mass of montmorillonite (anionic polymer composite refined bentonite; manufactured by HOJUN Co., Ltd., BEN-GEL W100U) in ion-exchanged water. Next, a PDMS-containing silicone resin composition (SILPOT) was defoamed using a defoaming agent (manufactured by Thinky Co., Ltd.). TM 184: 100 parts by weight of main agent, 10 parts by weight of curing agent: 110 parts by weight, montmorillonite dispersion water: 140 parts by weight, and surfactant (Kao Corporation, RHEODOL SP-O10V (HLB4.3) 96% by weight, RHEODOL SP-O30V (HLB1.8) 4% by weight): 1.3 parts by weight. Emulsification was carried out for 10 minutes. Next, the emulsion was degassed at 10 kPa using a degassing Rentaro vacuum type (Thinky Corporation) to prepare a coating liquid. A coating film (80 μm thick) was obtained by applying the coating liquid onto a release liner (Mitsubishi Chemical Corporation, MRE38). A release liner (Toray Industries, Lumirror75S10) was then applied over the coating film, and the silicone resin was cured by heating in a hot air oven at 85°C for 6 minutes. After curing, one release liner was peeled off to expose the surface of the cured silicone resin. Furthermore, by heating and drying at 150°C for 10 minutes, a laminate with a separation functional layer formed on the release liner is obtained.

[0204] Next, a PET nonwoven fabric is prepared as a porous support. The above-mentioned laminate is stacked on the porous support with the surface of the porous support in contact with the surface of the separation functional layer. Then, another release liner is removed. Following the above procedure, the permeation vaporization membrane of Example 1 is produced.

[0205] (Example 2) Except that the coating liquid was applied in such a way that the thickness of the coating film was 110 μm, the permeation vaporization membrane of Example 2 was prepared in the same manner as in Example 1.

[0206] (Example 3) Except that the mixing ratio of each material in the coating liquid was set as follows: PDMS-containing silicone resin composition: 110 parts by mass, montmorillonite dispersion water: 90 parts by mass, and surfactant (manufactured by Kao Corporation, RHEODOL SP-O10V (HLB4.3) 96% by mass, RHEODOL SP-O30V (HLB1.8) 4% by mass): 1.3 parts by mass, the permeation vaporization membrane of Example 3 was prepared in the same manner as in Example 1.

[0207] (Example 4) Except that the mixing ratio of each material in the coating liquid was set as follows: PDMS-containing silicone resin composition: 110 parts by mass, montmorillonite dispersion water: 50 parts by mass, and surfactant (manufactured by Kao Corporation, RHEODOL SP-O10V (HLB4.3) 96% by mass, RHEODOL SP-O30V (HLB1.8) 4% by mass): 1.3 parts by mass, the permeation vaporization membrane of Example 4 was prepared in the same manner as in Example 1.

[0208] (Example 5) Using degassing agent (Thinky Corporation) to prepare a silicone resin composition containing PDMS (SILPOT) TM 184: 100 parts by weight of main agent, 10 parts by weight of curing agent, 110 parts by weight of polyethylene glycol (manufactured by Fujifilm and Kazuko Pure Chemical Industries, Ltd., PEG200): 100 parts by weight, emulsified for 10 minutes. Next, the emulsion was degassed at 10 kPa using a degassing Rentaro vacuum type (manufactured by Thinky Corporation) to prepare a coating liquid. A coating film (80 μm thick) was obtained by applying the coating liquid onto a release liner (manufactured by Mitsubishi Chemical Corporation, MRE38). A release liner (manufactured by Toray Industries, Ltd., Lumirror 75S10) was then applied over the coating film, and the silicone resin was cured by heating in a hot air oven at 80°C for 60 minutes, followed by heating at 120°C for 60 minutes. After curing, one release liner was peeled off to expose the surface of the cured silicone resin. The cured silicone resin was immersed in a water bath at 50°C for 12 hours and then washed to obtain a laminate with a separation functional layer formed on the release liner.

[0209] Next, a PET nonwoven fabric is prepared as a porous support. The above-mentioned laminate is stacked on the porous support with the surface of the porous support in contact with the surface of the separation functional layer. Then, another release liner is removed. Following the above procedure, the permeation vaporization membrane of Example 5 is produced.

[0210] (Example 6) Except for replacing polyethylene glycol with glycerin (manufactured by Fujifilm and Koichi Chemical Co., Ltd.), the permeation vaporization membrane of Example 6 was prepared in the same manner as in Example 5.

[0211] (Example 7) Except for using PPS nonwoven fabric as a porous support, the permeation vaporization membrane of Example 7 was prepared in the same manner as in Example 1.

[0212] (Example 8) Except for using a laminate of a microporous layer made of polysulfone and a nonwoven fabric made of PET (made by Nitto Denko Corporation, CF-30S) as a porous support, the permeation vaporization membrane of Example 8 was prepared in the same manner as in Example 1.

[0213] (Example 9) Except for using RHEODOL MO-60 (HLB2.8) manufactured by Kao Corporation at a ratio of 2 parts by mass as the surfactant, the permeation vaporization membrane of Example 9 was prepared in the same manner as in Example 1. That is, in Example 9, the mixing ratio of the materials in the coating solution was: PDMS-containing silicone resin composition: 110 parts by mass, montmorillonite dispersion water: 140 parts by mass, and surfactant (RHEODOL MO-60 (HLB2.8) manufactured by Kao Corporation): 2 parts by mass.

[0214] (Comparative Example 1) The PDMS-containing silicone resin composition (SILPOT) TM 184: 100 parts by weight of the main agent and 10 parts by weight of the curing agent were coated onto a release liner (Toray Industries, Inc., Lumirror 75S10) to obtain a coated film (25 μm thick). Next, by heating at 150°C for 10 minutes, a laminate with a separation functional layer formed on the release liner was obtained. Except as described above, the pervaporation membrane of Comparative Example 1 was prepared in the same manner as in Example 1.

[0215] (Comparative Example 2) Except that the silicone resin composition containing PDMS was coated with a coating film of 80 μm thickness, the permeation vaporization membrane of Comparative Example 2 was prepared in the same manner as Comparative Example 1.

[0216] (Comparative Example 3) Except that the silicone resin composition containing PDMS was coated with a coating film of 110 μm thickness, the permeation vaporization membrane of Comparative Example 3 was prepared in the same manner as Comparative Example 1.

[0217] <Observation of the structure of separated functional layers> The cross-section of the separation functional layer was observed using a scanning electron microscope (Hitachi High-Tech Corporation, SU-3800) to confirm the presence or absence of a porous layer within the separation functional layer. In the pervaporation membranes of Examples 1-9, the separation functional layer comprises a porous layer containing pores and a skin layer. The pores in the porous layer form interconnecting pores with openings on the surface of the pervaporation membrane. In the pervaporation membranes of Comparative Examples 1-3, no porous layer containing pores was identified in the separation functional layer. Furthermore, the thickness of the separation functional layer, the thickness of the skin layer, and the average pore size in the porous layer were measured using the aforementioned cross-sectional observation. The measurement results are shown in Table 1.

[0218] <Porosity of the Separated Functional Layer> The porosity of the separation functional layer in the pervaporation membranes of Examples 1-9 was determined using the method described above. Specifically, five sections of the separation functional layer profile were observed using a scanning electron microscope (Hitachi High-Tech Corporation, SU-3800). The average area ratio of the pore portion in each section was taken as the porosity of the separation functional layer. The magnification was 500x. The measurement results are shown in Table 1.

[0219] <Separation Performance> (Separation performance of EtOH) For the pervaporation membranes of Examples 1-9 and Comparative Examples 1-3, the separation coefficient α of ethanol (EtOH) relative to water was determined using the following method. EtOH First, the pervaporation membrane was cut into 74 mm diameter pieces to serve as flat test pieces. These test pieces were then placed in an intermittent membrane separation unit. A mixture of ethanol (EtOH) and water was supplied to the unit's feed space. The EtOH content in the mixture was 2.0 wt%.

[0220] Next, the unit was immersed in a water bath, and the temperature of the mixed liquid was adjusted to 40°C. Then, using a stirrer located within the unit, the mixed liquid was stirred while the pressure in the permeation space was reduced to 15 hPa. This allowed the mixed liquid to permeate through the pervaporation membrane, yielding the gas permeate. The gas permeate was then cooled using a liquid nitrogen cooling trap, causing it to condense. The composition of the liquid permeate was analyzed using gas chromatography, and the separation coefficient α was calculated based on the results. EtOH and the flux of EtOH permeating from the pervaporation membrane [kg / m] 2 The evaluation results are shown in Table 1.

[0221] (IPA separation performance) For the pervaporation membranes of Example 9 and Comparative Example 1, the separation coefficient α of isopropanol (IPA) relative to water was determined using the following method. IPA First, a flat membrane-like test piece is obtained in the same manner as described above, and the test piece is placed in an intermittent membrane separation device (unit). A mixed liquid containing IPA and water is supplied to the supply space of this unit. The IPA content in the mixed liquid is 10 wt%.

[0222] Next, the unit was immersed in a water bath, and the temperature of the mixed liquid was adjusted to 40°C. Then, using a stirrer located within the unit, the mixed liquid was stirred while the pressure in the permeation space was reduced to 15 hPa. This allowed the mixed liquid to permeate through the pervaporation membrane, yielding the gas permeate. The gas permeate was then cooled using a liquid nitrogen cooling trap, causing it to condense. The composition of the liquid permeate was analyzed using gas chromatography, and the separation coefficient α was calculated based on the results. IPA and the flux of IPA permeating through the pervaporation membrane [kg / m] 2 The evaluation results are shown in Table 2.

[0223] (Separation performance of BuOH) For the pervaporation membranes of Example 9 and Comparative Example 1, the separation coefficient α of n-butanol (BuOH) relative to water was determined using the following method. BuOH First, a flat membrane-like test piece is obtained in the same manner as described above, and the test piece is placed in an intermittent membrane separation device (unit). A mixed liquid containing BuOH and water is supplied to the supply space of this unit. The BuOH content in the mixed liquid is 0.8 wt%.

[0224] Next, the unit was immersed in a water bath to adjust the temperature of the mixed liquid to 30°C. Then, using a stirrer located within the unit, the mixed liquid was stirred while the pressure in the permeation space was reduced to 15 hPa. The mixed liquid then permeated through the pervaporation membrane to obtain the gas permeate. The gas permeate was cooled using a liquid nitrogen cooling trap, causing it to condense. The composition of the liquid permeate was analyzed using gas chromatography, and based on the results, the separation coefficient αBuOH and the flux (flux) of BuOH permeating through the pervaporation membrane [kg / m³] were calculated. 2 The evaluation results are shown in Table 2.

[0225] [Table 1] [Table 2] Compared to the pervaporation membranes of Comparative Examples 1-3, which lack a porous layer in their separation functional layer, the pervaporation membranes of Examples 1-9, which have a porous layer and a skin layer in their separation functional layer, exhibit improved EtOH flux and a practically acceptable separation coefficient α. EtOH Furthermore, compared to the pervaporation membrane of Comparative Example 1, the pervaporation membrane of Example 9 also exhibits improved IPA flux and BuOH flux, and possesses a practically harmless separation coefficient α. IPA and separation coefficient α BuOHIn summary, the pervaporation membranes of Examples 1-9 are suitable for improving separation performance.

[0226] Industrial availability The pervaporation membrane of this embodiment is suitable for separating organic compounds from aqueous solutions containing volatile organic compounds.

Claims

1. A pervaporation membrane, which has a separation functional layer. The separation functional layer has a porous layer containing pores and a skin layer formed on the porous layer.

2. The pervaporation membrane as described in claim 1, wherein, The separation functional layer comprises a resin material.

3. The pervaporation membrane as described in claim 2, wherein, The resin material is an organosilicon resin.

4. The pervaporation membrane as described in claim 1, wherein, The average pore diameter of the pore is greater than 1 nm.

5. The pervaporation membrane as described in claim 1, wherein, The hole forms a connecting hole.

6. The pervaporation membrane as described in claim 1, wherein, The porosity of the separation functional layer is above 10%.

7. The permeation vaporization membrane as claimed in claim 1, further comprising a porous support body supporting the separation functional layer.

8. The pervaporation membrane as described in claim 7, wherein, The porous support is a fiber structure.

9. The pervaporation membrane as described in claim 1, wherein, The separation functional layer contains filler.

10. The pervaporation membrane of claim 1, used for separating said organic compound from an aqueous solution containing a volatile organic compound.

11. The pervaporation membrane as described in claim 10, wherein, The organic compound is an alcohol.

12. The pervaporation membrane as described in claim 11, wherein, The alcohol is ethanol.

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