Methods for manufacturing laminated membranes, laminated membranes and CO2 separation methods

Abstract

This invention provides a method for manufacturing a laminated membrane obtained by laminating a CO2 separation membrane and a support substrate, namely, a method for manufacturing a laminated membrane capable of manufacturing a large-scale CO2 separation membrane with suppressed defects, a laminated membrane, and a CO2 separation method using the laminated membrane. The method for manufacturing a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the CO2 separation membrane includes: a coating membrane forming step, forming a coating membrane on a sacrificial layer of a raw material composition comprising a raw material for the CO2 separation membrane; a porous membrane bonding step, bonding a porous membrane onto the coating membrane; and a sacrificial layer removal step, removing the sacrificial layer after the porous membrane bonding step. The raw material composition comprises a silicone resin and an organic solvent, wherein the silicone resin is a non-water-soluble resin and the weight-average molecular weight of the silicone resin is 2000 or more.

Description

Technical Field

[0001] This invention relates to a method for manufacturing laminated membranes, laminated membranes, and CO2 separation methods. Background Technology

[0002] In order to mitigate global warming caused by climate change and other factors, technologies have been developed that use CO2 separation membranes to separate and recover carbon dioxide (CO2) (e.g., Patent Document 1).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2018-15678 Summary of the Invention

[0004] The problem that the invention aims to solve In the manufacture of thin-film and large-scale CO2 separation membranes, there is a problem that defects such as gaps and pinholes are easily generated in the manufactured CO2 separation membrane. For example, it is possible to form a sacrificial layer on a support, form a CO2 separation membrane on the sacrificial layer, and then immerse it in a liquid such as ethanol to remove the sacrificial layer, thereby forming a thin-film and large-scale CO2 separation membrane. However, in this method, gaps and pinholes are generated in the manufactured membrane.

[0005] In the case of thin or large-scale CO2 separation membranes, standalone CO2 separation membranes are difficult to self-support and are prone to deformation and breakage. Therefore, a laminated membrane is considered, in which a support substrate (porous membrane) supporting (reinforcing) the CO2 separation membrane is attached to the CO2 separation membrane.

[0006] The present invention was made in view of the above-mentioned problems, and its object is to provide a method for manufacturing a laminated membrane that suppresses defects and is obtained by laminating a thin film and a large CO2 separation membrane with a support substrate; a laminated membrane; and a CO2 separation method using the laminated membrane.

[0007] Methods for solving problems The inventors of this application discovered that the above-mentioned problems could be solved by the following method for manufacturing a laminated membrane, thereby completing the present invention. The method for manufacturing a laminated membrane is a method for manufacturing a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the CO2 separation membrane. The method includes: a coating membrane forming step, forming a coating membrane on a sacrificial layer containing a raw material composition of the CO2 separation membrane raw material; a porous membrane bonding step, bonding a porous membrane onto the coating membrane; and a sacrificial layer removal step, removing the sacrificial layer after the porous membrane bonding step. The raw material composition contains a silicone resin and an organic solvent, the silicone resin being a non-water-soluble resin with a mass-average molecular weight of 2000 or more. Specifically, the present invention provides the following methods.

[0008] [1] A method for manufacturing a laminated membrane, which is a method for manufacturing a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the aforementioned CO2 separation membrane, the method for manufacturing the laminated membrane comprising: The coating film forming process forms a coating film on a sacrificial layer comprising a raw material composition containing the raw material of the aforementioned CO2 separation membrane; The porous membrane bonding process involves bonding the aforementioned porous membrane onto the aforementioned coated membrane; and The sacrificial layer removal process involves removing the aforementioned sacrificial layer after the porous membrane bonding process. The aforementioned raw material composition includes a silicone resin and an organic solvent. The aforementioned silicone resin is a non-water-soluble resin. The aforementioned silicone-containing resin has a mass-average molecular weight of 2000 or higher.

[0009] [2] The method for manufacturing the laminated membrane as described in [1] above, wherein the area of ​​the aforementioned CO2 separation membrane is 0.03 m². 2 The above refers to thicknesses ranging from 1 nm to 10,000 nm.

[0010] [3] The method for manufacturing a laminated film as described in [1] or [2] above, wherein the aforementioned silicone resin comprises polydimethylsiloxane.

[0011] [4] The method for manufacturing the laminated membrane as described in [3] above includes a curing step of curing the aforementioned polydimethylsiloxane after the aforementioned porous membrane bonding step and before the aforementioned sacrificial layer removal step.

[0012] [5] The method for manufacturing a laminated membrane as described in any one of [1] to [4] above, wherein the aforementioned porous membrane is a porous membrane formed from polyimide.

[0013] [6] The method for manufacturing a laminated membrane as described in any one of [1] to [5] above, wherein the pore size of the aforementioned porous membrane is 1 mm or less.

[0014] [7] The method for manufacturing a laminated film as described in any one of [1] to [6] above, the method comprising: The sacrificial layer forming process involves forming the sacrificial layer on the support of the sacrificial layer prior to the aforementioned coating film forming process; and The support peeling process involves peeling the support from the sacrificial layer after the aforementioned porous membrane bonding process and before the aforementioned sacrificial layer removal process.

[0015] [8] The method for manufacturing a laminated film as described in [7] above, wherein the aforementioned support is a film formed from polyethylene terephthalate.

[0016] [9] The method for manufacturing a laminated film as described in any one of [1] to [8] above, wherein the laminated film is a wound film roll.

[0017]

[10] A laminated membrane, which is a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the aforementioned CO2 separation membrane. The area of ​​the aforementioned CO2 separation membrane is 0.03 m². 2 The above refers to thicknesses ranging from 1 nm to 10,000 nm.

[0018]

[11] As described in

[10] above, the laminated film is a film roll wound into a roll.

[0019]

[12] A CO2 separation method comprising a separation step of supplying a gas containing CO2 to the laminated membrane described in

[10] or

[11] above, thereby separating CO2 from the gas.

[0020] Invention Effects According to the present invention, a method for manufacturing a laminated membrane capable of producing a laminated membrane obtained by laminating a thin film and a large CO2 separation membrane with a support substrate, the laminated membrane being able to suppress defects; the laminated membrane; and a CO2 separation method using the laminated membrane are provided. Attached Figure Description

[0021] [ Figure 1 This is a schematic diagram used to illustrate a method for manufacturing a laminated film. Detailed Implementation

[0022] Manufacturing Methods of Laminated Films The method for manufacturing a laminated membrane is a method for laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the CO2 separation membrane. The laminated membrane can also be manufactured as a wound membrane roll.

[0023] The manufacturing method of laminated films has the following characteristics: The coating film forming process forms a coating film on a sacrificial layer of a raw material composition containing a raw material for a CO2 separation membrane; The porous membrane bonding process involves bonding a porous membrane onto a coated membrane; and The sacrificial layer removal process is performed after the porous membrane bonding process to remove the sacrificial layer.

[0024] The raw material composition contains silicone resin and organic solvent.

[0025] Silicone-containing resins are non-water-soluble resins, and their mass-average molecular weight is above 2000.

[0026] By using such a method for manufacturing laminated membranes, as shown in the examples described later, it is possible to manufacture laminated membranes consisting of a thin, large CO2 separation membrane with defects such as gaps and pinholes suppressed, and a porous membrane (supporting substrate).

[0027] Furthermore, as shown in the process steps constituting the above manufacturing method, the above manufacturing method has excellent continuous production capacity (mass production capacity).

[0028] The CO2 separation membrane in the manufactured laminated membrane has, for example, an area of ​​0.03 m². 2 The above refers to thicknesses ranging from 1 nm to 10,000 nm.

[0029] The area of ​​the CO2 separation membrane is preferably 0.05m². 2 The area of ​​the CO2 separation membrane is preferably 0.03 m². 2 Above 1000m 2 Hereinafter, 0.05m is more preferred. 2 Above 800m 2 Hereinafter, 0.1m is further preferred. 2 Above 500m 2 the following.

[0030] The thickness of the CO2 separation membrane is preferably 50 nm to 5000 nm, and more preferably 80 nm to 1000 nm.

[0031] The method for manufacturing laminated membranes may include a curing step in which the polydimethylsiloxane is cured after the porous membrane bonding step and before the sacrificial layer removal step.

[0032] Alternatively, the manufacturing method of the laminated membrane may include: a sacrificial layer forming step, in which a sacrificial layer is formed on a support for the sacrificial layer before the coating membrane forming step; and a support peeling step, in which the support is peeled off from the sacrificial layer after the porous membrane bonding step and before the sacrificial layer removal step.

[0033] For each process, the following is used Figure 1 Please provide an explanation. Figure 1 This is a schematic diagram used to illustrate a method for manufacturing a laminated film.

[0034] [Sacrificial layer formation process] In the process of forming the sacrificial layer, the sacrificial layer 2 is formed on the support 1 of the sacrificial layer 2. Figure 1 (a)).

[0035] Sacrificial layer 2 is typically formed using a composition for forming sacrificial layers.

[0036] The composition for forming the sacrificial layer is not particularly limited as long as it is capable of forming a sacrificial layer that can be removed by a subsequent sacrificial layer removal process. Typically, the composition for forming the sacrificial layer includes a resin and a solvent.

[0037] Examples of resins included in the composition for forming the sacrificial layer include polyvinyl alcohol resin, dextrin, gelatin, animal glue, casein, shellac, gum arabic, starch, protein, polyacrylamide, sodium polyacrylate, polyvinyl methyl ether, copolymer of methyl vinyl ether and maleic anhydride, copolymer of vinyl acetate and itaconic acid, polyvinylpyrrolidone, acetylcellulose, acetylbutylcellulose, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, etc.

[0038] The amount of resin contained in the composition for forming the sacrificial layer is not particularly limited without affecting the purpose of the present invention, and can be appropriately determined by taking into account factors such as the coatability of the composition for forming the sacrificial layer.

[0039] When the mass of the resin in the composition for forming the sacrificial layer is set to 100 parts by mass, the amount of solvent is preferably 100 parts by mass or more and 10,000 parts by mass or less, more preferably 500 parts by mass or more and 8,000 parts by mass or less, and particularly preferably 700 parts by mass or more and 6,000 parts by mass or less.

[0040] The solvent included in the sacrificial layer forming composition is not particularly limited as long as it is a solvent capable of dissolving the resin. If a predetermined amount of resin has already been dissolved in the sacrificial layer forming composition, the composition may also contain undissolved resin. Preferably, the resin is completely dissolved in the sacrificial layer forming composition.

[0041] The solvent can be water, an organic solvent, or an aqueous solution of an organic solvent.

[0042] Specific examples of organic solvents used as solvents include: Methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethyl-1-butanol, sec-heptanol, 3-heptanol, 1-octanol, 2-ethylhexanol, sec-octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecanol, trimethylnonanol, sec-tetradecanol, sec-heptadecanol, methyl isobutyl methanol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethyl methanol, diacetone alcohol, cresol and other monohydric alcohol solvents; Sulfoxides such as dimethyl sulfoxide; Sulfones such as dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone; Amides such as N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and other lactams; Imidazolinones such as 1,3-dimethyl-2-imidazolinone, 1,3-diethyl-2-imidazolinone, and 1,3-diisopropyl-2-imidazolinone; Dialkyl glycol ethers, such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, ethylene glycol diethyl ether, and triethylene glycol butyl methyl ether; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, etc. (poly)alkylene glycol monoalkyl ethers; Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, etc. (poly)alkylene glycol monoalkyl ether acetates; Dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisopentyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran and other ethers; Ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone; alkyl lactate esters such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; Ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxypropionate, ethyl hydroxypropionate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methyl-3-methoxybutylacetate, methyl 3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl formate, isopentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutyrate, and other esters; β-propiolactone, γ-butyrolactone, δ-valerolactone, and other lactones; Straight-chain, branched, or cyclic aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, n-nonane, methyloctane, n-decane, n-undecane, n-dodecane, 2,2,4,6,6-pentamethylheptane, 2,2,4,4,6,8,8-heptamethylnonane, cyclohexane, and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene, 1,3,5-trimethylbenzene, and naphthalene; Terpenes such as menthol, diphenylmenthol, limonene, terpinene, camphene, norbornene, pinane, etc.

[0043] When the solvent is a mixture of water and an organic solvent, the content of the organic solvent in the solvent is preferably 10% by mass or more, and more preferably 20% by mass or more.

[0044] The sacrificial layer forming composition may also contain various components other than resin and solvent, to the extent that it does not impair the purpose of the present invention. Examples of other components include viscosity modifiers, surfactants, and defoamers.

[0045] There are no particular limitations on the method for preparing the composition for sacrificial layer formation. Typically, the composition for sacrificial layer formation can be prepared by uniformly mixing each of a specified amount of resin, solvent, and other components as needed.

[0046] Examples of substrates that can serve as the support for the sacrificial layer 2 include resin films such as PET (polyethylene terephthalate) films, silicon substrates, and glass substrates. The surface of the support 1 to which the sacrificial layer 2 is to be formed can be treated with a release agent, or it can remain untreated.

[0047] The shape of the support 1 is not particularly limited; it can be either membrane-like or plate-like. When the support is membrane-like, a membrane drawn from a membrane roll can be used as the support 1.

[0048] There is no particular limitation on the method of forming the sacrificial layer 2 on the support 1 using the sacrificial layer forming composition. Examples of coating methods include bar coating, stencil coating, gravure coating, spin coating, spray coating, roller coating, and dipping.

[0049] After the sacrificial layer forming composition is coated onto the support 1, the coated film of the sacrificial layer forming composition may be heated (dried) as needed to remove at least a portion of the solvent of the sacrificial layer forming composition.

[0050] The heating temperature of the coating film of the composition for forming the sacrificial layer is, for example, 50°C or higher and 90°C or lower. Alternatively, the coating film may be heated at a low temperature (e.g., 50°C or higher and less than 70°C) and then heated at a high temperature (e.g., 70°C or higher and 90°C or lower).

[0051] The thickness of the sacrificial layer 2 is not particularly limited, but is preferably 1 μm or more and 20 μm or less, more preferably 3 μm or more and 18 μm or less, and even more preferably 5 μm or more and 15 μm or less.

[0052] [Coating film formation process] In the coating film forming process, a coating film 3a is formed on the sacrificial layer 2 by forming a raw material composition (composition for coating film forming) containing the raw material of the CO2 separation membrane. Figure 1 (b)

[0053] The raw material composition (composition for CO2 separation membrane formation) contains a silicone resin and an organic solvent.

[0054] Silicone-containing resins are non-water-soluble resins, and their mass-average molecular weight is above 2000.

[0055] So-called non-water-soluble resins are resins that can dissolve less than 1.0g in 100g of water at 25℃.

[0056] Examples of silicone-containing resins include organosilicon resins (resins with siloxane bonds in their main backbone). Preferred organosilicon resins are polyorganosiloxanes such as polydimethylsiloxane, polyphenylmethylsiloxane, and polydiphenylsiloxane, with polydimethylsiloxane being more preferred. Polyorganosiloxanes can also be used together with a curing agent for the polyorganosiloxane.

[0057] Silicone-containing resins may also have hydroxyl groups at both ends or one end of the molecular chain.

[0058] In addition, silicone resins can also be used as elastomers.

[0059] The mass-average molecular weight (Mw) of the silicone resin is 2,000 or more, preferably 2,200 or more but less than 200,000, and more preferably 2,500 or more but less than 120,000.

[0060] It should be noted that, in this specification, the mass-average molecular weight Mw can be defined as a relative value converted to polystyrene in GPC (gel permeation chromatography) determination.

[0061] The curing agent included in the raw material composition along with the polyorganosiloxane is a curing agent for curing the polyorganosiloxane.

[0062] Examples of curing agents include alkoxysilanes such as tetramethoxysilane, trimethoxymethylsilane, dimethoxydimethylsilane, methoxytrimethylsilane, and γ-glycidyl etheroxypropyltrimethoxysilane.

[0063] The content of the curing agent in the raw material composition is not particularly limited. In the raw material composition, the content of the curing agent is preferably more than 1 part by weight and less than 20 parts by weight relative to 100 parts by weight of polyorganosiloxane, more preferably more than 5 parts by weight and less than 15 parts by weight.

[0064] Examples of solvents included in the raw material composition include sulfoxides, sulfones, amides, lactams, imidazolinones, dialkyl glycol ethers, (poly)alkylene glycol monoalkyl ethers, (poly)alkylene glycol monoalkyl ether acetates, other ethers, ketones, other esters, lactones, linear, branched or cyclic aliphatic hydrocarbons, aromatic hydrocarbons, terpenes, etc.

[0065] Dimethyl sulfoxide (DMSO) is an example of a sulfoxide.

[0066] Examples of sulfones include dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone.

[0067] Examples of amides include N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide.

[0068] Examples of lactams include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone.

[0069] Examples of imidazolinones include 1,3-dimethyl-2-imidazolinone, 1,3-diethyl-2-imidazolinone, and 1,3-diisopropyl-2-imidazolinone.

[0070] Examples of dialkyl glycol ethers include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, ethylene glycol diethyl ether, and triethylene glycol butyl methyl ether.

[0071] Examples of (poly)alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether.

[0072] Examples of (poly)alkylene glycol monoalkyl ether acetates include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate.

[0073] Other ethers include, for example, dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisopentyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and tetrahydrofuran.

[0074] Examples of ketones include methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, and 2,6-dimethyl-4-heptanone.

[0075] Other examples of esters include alkyl lactate esters such as methyl lactate and ethyl lactate; ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxypropionate, ethyl hydroxypropionate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxybutylacetic acid, methyl-3-methoxy-1-butylacetic acid, methyl-3-methoxybutylpropionate, etc. Ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, n-hexyl acetate, n-heptyl acetate, n-octyl acetate, n-pentyl formate, isopentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, butyl butyrate, methyl octanoate, methyl decanoate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutyrate, dimethyl adipate, propylene glycol diacetate.

[0076] Examples of lactones include propiolactone, γ-butyrolactone, and 6-pentanolactone.

[0077] Examples of linear, branched, or cyclic aliphatic hydrocarbons include n-hexane, n-heptane, n-octane, n-nonane, methyloctane, n-decane, n-undecane, n-dodecane, 2,2,4,6,6-pentamethylheptane, 2,2,4,4,6,8,8-heptamethylnonane, cyclohexane, and methylcyclohexane.

[0078] Examples of aromatic hydrocarbons include benzene, toluene, trifluorotoluene, xylene, 1,3,5-trimethylbenzene, naphthalene, and decahydronaphthalene.

[0079] Examples of terpenes include p-menthane, diphenylmenthane, limonene, terpinene, camphene, norbornane, and pinane.

[0080] The viscosity of the raw material composition at 24°C is preferably 5 cp or more and 500 cp or less, more preferably 10 cp or more and 200 cp or less, and even more preferably 20 cp or more and 100 cp or less.

[0081] In addition, the concentration of solid components in the raw material composition is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 18% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less.

[0082] There are no particular limitations on the method for preparing the raw material composition. Typically, the raw material composition can be prepared by uniformly mixing a silicone resin, a solvent, and a curing agent, if desired.

[0083] After the raw material composition is coated onto the sacrificial layer 2, the coated film may be heated (dried) as needed to remove at least a portion of the solvent of the film-forming composition.

[0084] The heating (drying) temperature of the coated film is, for example, above 40°C and below 60°C.

[0085] The heating (drying) time for the coated film is, for example, more than 0.5 minutes and less than 1 minute.

[0086] [Porous membrane bonding process] In the porous membrane bonding process, a porous membrane 4, which serves as a support substrate for the CO2 separation membrane, is bonded onto the coated membrane 3a. Figure 1 (c) It should be noted that the CO2 separation membrane is formed by coating membrane 3a.

[0087] In the case of thin or large-scale CO2 separation membranes, standalone CO2 separation membranes are difficult to self-support and are prone to deformation and breakage. By bonding a porous membrane 4 to support (reinforce) the CO2 separation membrane, deformation and breakage can be suppressed, and the separation performance of the CO2 separation membrane can be maintained.

[0088] The pore size of the porous membrane 4 is preferably less than 1 mm, more preferably more than 1 nm and less than 10,000 nm, and even more preferably more than 10 nm and less than 5,000 nm.

[0089] The pore size (average fine pore size) of the porous membrane 4 can be determined by measuring the fine pore size distribution using a through-pore size evaluation device based on the bubble point method according to ASTM F316-86 (JIS K 3832). An example of the membrane pore size analyzer (through-pore size distribution measuring device) used in the measurement is the NanopermPorometer from SEIKA Digital Image Corporation.

[0090] The material used for the porous membrane 4 can be either an organic or inorganic material, but is preferably an organic material. Typically, this organic material is a resin.

[0091] Examples of resins include polyacetal, polyamide, polycarbonate, polyester (polybutylene terephthalate, polyethylene terephthalate, polyarylate, etc.), FR-AS resin, FR-ABS resin, AS resin, ABS resin, polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, fluorinated resins (polytetrafluoroethylene, polyvinylidene fluoride, etc.), polyimide, polyamide imide, polyamide bismaleimide, polyetherimide, polybenzoxazole, polybenzothiazole, polybenzimidazole, silicone resin, BT resin, polymethylpentene, ultra-high molecular weight polyethylene, FR-polypropylene, (meth)acrylic resin (polymethyl methacrylate, etc.), and polystyrene.

[0092] Among resins, polyvinylidene fluoride, polyethersulfone, polyimide, and polyamide-imide are preferred from the perspective of easily obtaining films that are thermally or chemically stable and have excellent mechanical strength.

[0093] As a material for porous membranes, two or more resins can also be used in combination.

[0094] The porous membrane 4 is membrane-like in shape. A membrane drawn from a membrane roll can be used as the porous membrane 4.

[0095] The thickness of the porous membrane 4 is not particularly limited, but is preferably 1 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less, and even more preferably 20 μm or more and 60 μm or less.

[0096] There are no particular limitations on the method of bonding the porous membrane 4 to the coated membrane 3a. Examples include lamination and transfer printing using intermolecular forces. The coated membrane 3a and the porous membrane 4 can be bonded even without the use of an adhesive.

[0097] For example, a roller 11 or similar device can be used to press (hot-press) the membrane 3 onto the porous membrane 4 under pressure that does not damage the porous membrane 4. Regarding the hot-pressing conditions, the roller pressure is preferably 0.1 kgf / cm². 2 Above 10 kgf / cm 2 The following is more preferably 0.2 kgf / cm 2 Above 5kgf / cm 2 The temperature of the roller is preferably 20°C to 120°C, and more preferably 25°C to 100°C.

[0098] In the case of intermolecular forces, for example, it is sufficient to simply bring the coated membrane 3a into contact with the porous membrane 4.

[0099] [Curing Process] When the raw material composition for forming the coating film in the coating film forming process includes polydimethylsiloxane as a silicone resin, a curing process may also be included, in which the polydimethylsiloxane is cured after the porous film bonding process and before the sacrificial layer removal process.

[0100] During the curing process, the coated membrane is cured to become a cured membrane (CO2 separation membrane 3). It should be noted that, without a curing process, the coated membrane 3a can also be a CO2 separation membrane 3.

[0101] One method for curing is heating the coated film. Alternatively, the solvent can be removed during the heating process of the curing step.

[0102] The heating temperature of the coating film is, for example, 100°C or higher and 160°C or lower, preferably 105°C or higher and 150°C or lower.

[0103] In addition, the heating time for the coating film is, for example, more than 1 minute and less than 10 minutes, preferably more than 2 minutes and less than 5 minutes.

[0104] [Support Stripping Process] In the support peeling process, support 1 is peeled from sacrificial layer 2. Figure 1 (d)

[0105] There is no particular limitation on the method for peeling the support 1 from the sacrificial layer 2. Methods for removing the support 1 from the sacrificial layer 2 without using a stripping fluid or the like can be given. If the support 1 is film-like, it can be peeled from the sacrificial layer 2 by unwinding the film. When peeling the support 1 from the sacrificial layer 2, a portion of the sacrificial layer 2 may also be peeled off along with the support 1.

[0106] [Sacrificial layer removal process] In the process of removing the sacrificial layer, sacrificial layer 2 is removed. Figure 1(e)). Thus, it is possible to manufacture a laminated membrane 10 obtained by stacking a CO2 separation membrane 3 and a porous membrane 4. Figure 1 (f)). The laminated membrane 10 can also be dried using airflow, a dryer, etc., as needed.

[0107] Sacrificial layer 2 can typically be removed by dissolving it in a liquid.

[0108] The liquid used to dissolve the sacrificial layer 2 can be water, an organic solvent, or a mixture of water and an organic solvent. When dissolving the sacrificial layer with these liquids, sometimes a portion of the sacrificial layer remains undissolved in the liquid. To remove the remaining sacrificial layer, it is preferable, for example, to further dissolve the sacrificial layer using an alkaline aqueous solution.

[0109] There is no particular limitation on the method of dissolving the sacrificial layer 2 in the liquid. Examples include washing the sacrificial layer 2 with running water, immersing the sacrificial layer 2 in the liquid, and blowing the sacrificial layer 2 with liquid sprayed from a shower head.

[0110] There is no particular limit to the running water washing time of the sacrificial layer 2, for example, it can be more than 1 minute and less than 30 minutes.

[0111] There is no particular limitation on the immersion time of the sacrificial layer 2 in the liquid, for example, it can be more than 5 minutes and less than 120 minutes.

[0112] There is no particular limitation on the time for the liquid to be blown into the sacrificial layer 2, for example, it can be more than 2 minutes and less than 5 minutes.

[0113] In addition, there are no special restrictions on the temperature of the liquid, such as 10°C to 40°C, or 20°C to 30°C.

[0114] Laminated Membranes The laminated membrane is a membrane formed by stacking a CO2 separation membrane and a porous membrane serving as a supporting substrate for the CO2 separation membrane. The area of ​​the CO2 separation membrane is 0.03 m². 2 The thickness is above 1 nm and below 10000 nm. The preferred area of ​​the CO2 separation membrane is 0.05 m². 2 The area of ​​the CO2 separation membrane is preferably 0.03 m². 2 Above 1000m 2 Hereinafter, 0.05m is more preferred. 2 Above 800m 2 Hereinafter, 0.1m is further preferred. 2 Above 500m 2 The thickness of the CO2 separation membrane is preferably 50 nm to 5000 nm, and more preferably 80 nm to 1000 nm.

[0115] Such laminated films were difficult to manufacture in the past, but they can be manufactured using the laminated film manufacturing method described above.

[0116] The shape of the laminated membrane is not particularly limited. From the viewpoint of ease of handling, the laminated membrane is preferably a membrane roll wound into a roll.

[0117] CO2 Separation Methods The CO2 separation method includes a separation step of supplying a CO2-containing gas to the aforementioned laminated membrane to separate CO2 from the gas.

[0118] The aforementioned laminated membrane has defects suppressed, is a thin film, and is a large CO2 separation membrane, thus enabling high-performance and high-volume CO2 separation.

[0119] By using such CO2 separation methods to separate and recover CO2, it is possible to mitigate global warming caused by CO2.

[0120] In addition, the recovered CO2 can be utilized as a carbon resource.

[0121] Example The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0122] [Example] <Preparation of the raw material composition (composition for coating film formation)> 100 parts by weight of PDMS elastomer (weight-average molecular weight Mn2500) and 10 parts by weight of PDMS elastomer curing agent were dissolved in decahydronaphthalene to prepare a raw material composition (composition for coating film formation) at a PDMS elastomer concentration of 5% by weight. The viscosity of the obtained raw material composition at 24°C was 20 cp.

[0123] <Manufacturing of Laminated Films> First, a 10% by mass ethanol solution of polyvinyl alcohol, which is the composition for forming the sacrificial layer, is coated onto the support 1 using a gravure coating method, thereby forming a sacrificial layer 2 with a film thickness of 15 μm on the support (PET film) 1.

[0124] Next, the raw material composition (composition for coating film formation) is coated in layers onto the sacrificial layer 2 using a gravure coating method, and heated at 50°C for 0.5 minutes to form a gel-like PDMS film 3a.

[0125] Next, a support substrate (porous polyimide film with a pore size of 50 nm to 2500 nm) 4 is laminated on the gel-like PDMS film 3a. The support substrate 4 is brought into contact with the PDMS film 3a by a roller, thereby using intermolecular forces to bond the support substrate 4 and the PDMS film 3a together.

[0126] Next, the bonded support substrate 4 and PDMS film 3a are heated at 110°C for 3 minutes to crosslink (cur) the PDMS and form a cured film (CO2 separation membrane).

[0127] Next, the support (PET film) 1 is peeled off from the sacrificial layer 2 by unwinding the support (PET film) 1 at a conveying speed of 0.6 m / min.

[0128] After peeling off the support 1, the exposed sacrificial layer 2 is washed with running water for 5 minutes at room temperature (25°C) to obtain a laminate 10 consisting of a cured membrane (CO2 separation membrane) 3 and a support substrate (porous polyimide membrane) 4. The thickness of the cured membrane (CO2 separation membrane) 3 is 1000 nm.

[0129] Through the above operations, cured membranes (CO2 separation membranes) of various sizes were manufactured, and the surface of the cured membranes was visually observed (observation area: 5 cm square). The results showed that the cured membranes ranged from 0.0025 μm... 2 (5cm square) to a size of 0.05m 2 0.06m 2 (A4 size), 130m 2 No defects (notches, pinholes) were observed in these large cured films. It should be noted that when manufacturing small-sized cured films, rod coating was used instead of gravure coating as a coating method.

[0130] Therefore, it can be seen that, according to the above-described method for manufacturing laminated membranes, it is possible to manufacture laminated membranes consisting of a thin, large CO2 separation membrane with suppressed defects and a supporting substrate (porous membrane).

[0131] [Comparative Example 1] The silicon wafer, which has been washed with piranha solution, is prepared as a support.

[0132] 100 μL of a 15% by mass ethanol solution of polyvinyl alcohol, which is a composition for forming a sacrificial layer, is dropped onto a support (silicon wafer), and the mixture is coated by spin coating (500 rpm, 20 seconds) to form a sacrificial layer with a film thickness of 15 μm.

[0133] Next, the raw material composition (composition for coating film formation) prepared in Example 1 was coated in layers onto the sacrificial layer using a spin coating method (1000 rpm, 20 seconds). The PDMS was then crosslinked (cured) by heating at 120°C for 5 minutes with a heating plate to form a cured film (CO2 separation membrane).

[0134] After crosslinking, the membrane is cooled to room temperature in air and then immersed in ethanol. At this point, slits are made at the ends of the cured membrane (CO2 separation membrane) and the sacrificial layer using a scribe. After a period of time, the sacrificial layer dissolves into the ethanol, and the cured membrane (CO2 separation membrane) peels off from the support. The solvent is then removed, the membrane is dried, and the cured membrane (CO2 separation membrane) is separated.

[0135] It should be noted that, as mentioned above, the method of Comparative Example 1 includes processes such as spin coating, room temperature placement, and cutting with a cutting tool that are not suitable for continuous production (mass production).

[0136] Through the above operations, cured membranes (CO2 separation membranes) of various sizes were manufactured, and the surface of the cured membranes was visually observed (observation area: 5 cm square). The result was 0.0025 m... 2 Notches and pinholes were observed in cured films of 5 cm square or larger.

[0137] Explanation of reference numerals in the attached figures 1 Support body 2. Sacrificial Layer 3a Coated film 3. Cured membrane (CO2 separation membrane) 4 Support substrate 10-layer film 11 rollers

Claims

1. A method for manufacturing a laminated membrane, comprising: a method for manufacturing a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the CO2 separation membrane, the method comprising: The coating film forming process forms a coating film on a sacrificial layer of a raw material composition containing the raw material of the CO2 separation membrane; The porous membrane bonding process involves bonding the porous membrane onto the coated membrane; and The sacrificial layer removal process involves removing the sacrificial layer after the porous membrane bonding process. The raw material composition comprises a silicone resin and an organic solvent. The silicone-containing resin is a non-water-soluble resin. The mass-average molecular weight of the silicone resin is above 2000.

2. The method for manufacturing a laminated film as described in claim 1, wherein, The area of ​​the CO2 separation membrane is 0.03m². 2 The above refers to thicknesses ranging from 1 nm to 10,000 nm.

3. The method for manufacturing a laminated film as described in claim 1, wherein, The silicone-containing resin comprises polydimethylsiloxane.

4. The method for manufacturing a laminated membrane as claimed in claim 3, comprising a curing step of curing the polydimethylsiloxane after the porous membrane bonding step and before the sacrificial layer removal step.

5. The method for manufacturing a laminated film as described in claim 1, wherein, The porous membrane is a porous membrane formed from polyimide.

6. The method for manufacturing a laminated film as described in claim 1, wherein, The pore size of the porous membrane is less than 1 mm.

7. The method for manufacturing a laminated film according to any one of claims 1 to 6, wherein the method for manufacturing the laminated film comprises: The sacrificial layer forming process involves forming the sacrificial layer on the support of the sacrificial layer prior to the coating film forming process. and The support peeling process involves peeling the support from the sacrificial layer after the porous membrane bonding process and before the sacrificial layer removal process.

8. The method for manufacturing a laminated film as described in claim 7, wherein, The support is a film formed from polyethylene terephthalate.

9. The method for manufacturing a laminated film as described in claim 1, wherein, The laminated film is a wound film roll.

10. A laminated membrane, which is a laminated membrane obtained by laminating a CO2 separation membrane and a porous membrane serving as a support substrate for the CO2 separation membrane. The area of ​​the CO2 separation membrane is 0.03m². 2 The above refers to thicknesses ranging from 1 nm to 10,000 nm.

11. The laminated film as claimed in claim 10, wherein it is a film roll wound into a roll shape.

12. A CO2 separation method comprising a separation step of supplying a gas containing CO2 to a laminated membrane as described in claim 10 or 11 to separate CO2 from the gas.

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