Method for producing laminate film, laminate film and co2 separation method

Abstract

To provide a method for producing a laminate film where a CO2 separation membrane and a support base material are laminated, which can produce a laminate film that suppresses defects and has a thin and large CO2 separation membrane, a laminate film, and a CO2 separation method using the laminate film.SOLUTION: A method for producing a laminate film where a CO2 separation membrane and a porous film being a support base material of the CO2 separation membrane are laminated includes a coating film formation step of forming a coating film of a raw material composition containing a raw material of the CO2 separation membrane on a sacrifice layer, a porous film bonding step of bonding the porous film onto the coating film, and a sacrifice layer removing step of removing the sacrifice layer after the porous film bonding step, wherein the raw material composition contains a silicon-containing resin and an organic solvent, the silicon-containing resin is a water-insoluble resin, and a mass average molecular weight of the silicon-containing resin is 2,000 or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a laminated film, a laminated film, and a CO2 separation method. [Background technology]

[0002] In order to suppress global warming due to climate change and the like, technologies have been developed for separating and capturing carbon dioxide (CO2) using a CO2 separation membrane (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-15678 A Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing a thin and large CO2 separation membrane, there is a problem that the manufactured CO2 separation membrane is likely to have defects such as chips and pinholes. For example, it is possible to form a thin and large CO2 separation membrane by forming a sacrificial layer on a support, forming a CO2 separation membrane on the sacrificial layer, and then immersing the membrane in a liquid such as ethanol to remove the sacrificial layer. However, this method causes chips and pinholes in the manufactured membrane.

[0005] Here, if the CO2 separation membrane is a thin or large membrane, it is difficult for the CO2 separation membrane to stand on its own and is prone to deformation and breakage. For this reason, it is possible to use the CO2 separation membrane as a laminated film in which a support substrate (porous membrane) that supports (reinforces) the CO2 separation membrane is attached to the CO2 separation membrane.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for producing a laminated film, a laminated film, and a CO2 separation method using a laminated film, which are capable of producing a laminated film in which defects are suppressed and a thin, large CO2 separation membrane and a supporting substrate are laminated. [Means for solving the problem]

[0007] The present inventors have found that the above-mentioned problems can be solved by a method for producing a laminated film in which a CO2 separation membrane and a porous membrane, which is a support substrate for the CO2 separation membrane, are laminated, the method comprising a coating film forming step of forming a coating film of a raw material composition containing raw materials for the CO2 separation membrane on a sacrificial layer, a porous membrane adhering step of adhering a porous membrane on the coating film, and a sacrificial layer removing step of removing the sacrificial layer after the porous membrane adhering step, the raw material composition containing a silicon-containing resin and an organic solvent, the silicon-containing resin being a water-insoluble resin, and the mass average molecular weight of the silicon-containing resin being 2000 or more, and have completed the present invention. Specifically, the present invention provides the following.

[0008] [1] A method for producing a laminated film in which a CO2 separation membrane and a porous membrane that is a support substrate for the CO2 separation membrane are laminated, comprising the steps of: A coating film formation step of forming a coating film of a raw material composition containing raw materials of the CO2 separation membrane on a sacrificial layer; a porous membrane adhering step of adhering the porous membrane onto the coating membrane; A sacrificial layer removal step of removing the sacrificial layer after the porous membrane bonding step, The raw material composition contains a silicon-containing resin and an organic solvent, The silicon-containing resin is a water-insoluble resin, A method for producing a laminated film, wherein the silicon-containing resin has a mass average molecular weight of 2000 or more.

[0009] [2] The CO2 separation membrane has an area of ​​0.03 m 2 and a thickness of 1 nm or more and 10,000 nm or less.

[0010] [3] The method for producing a laminated film according to the above [1] or [2], wherein the silicon-containing resin contains polydimethylsiloxane.

[0011] [4] The method for producing a laminated film according to the above [3], further comprising a curing step of curing the polydimethylsiloxane after the porous membrane bonding step and before the sacrificial layer removing step.

[0012] [5] The method for producing a laminated film according to any one of the above [1] to [4], wherein the porous film is a porous film made of polyimide.

[0013] [6] The method for producing a laminated film according to any one of the above [1] to [5], wherein the porous membrane has a pore size of 1 mm or less.

[0014] [7] a sacrificial layer forming step of forming the sacrificial layer on a support of the sacrificial layer before the coating film forming step; The method for producing a laminated film according to any one of the above [1] to [6], further comprising a support peeling step of peeling the support from the sacrificial layer after the porous membrane bonding step and before the sacrificial layer removing step.

[0015] [8] The method for producing a laminated film described in [7] above, wherein the support is a film made of polyethylene terephthalate.

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

[0017]

[10] A laminated film comprising a CO2 separation membrane and a porous membrane that is a support substrate for the CO2 separation membrane, The CO2 separation membrane has an area of ​​0.03 m 2 and a thickness of 1 nm or more and 10,000 nm or less.

[0018]

[11] The laminate film according to the above

[10] , which is a film roll wound into a roll shape.

[0019]

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

[10] or

[11] above, and separating CO2 from the gas. Effect of the Invention

[0020] According to the present invention, it is possible to provide a method for producing a laminated film, which is capable of producing a laminated film in which defects are suppressed and a thin, large CO2 separation membrane and a supporting substrate are laminated, a laminated film, and a CO2 separation method using the laminated film. [Brief description of the drawings]

[0021] [Figure 1] 1A to 1C are schematic diagrams illustrating a method for producing a laminated film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] <Laminated film manufacturing method> The method for producing a laminated film is a method for producing a laminated film in which a CO2 separation membrane and a porous membrane that is a support substrate for the CO2 separation membrane are laminated. A wound film roll can also be produced as the laminated film. The method for producing the laminated film includes the steps of: A coating film formation process of forming a coating film of a raw material composition containing raw materials for the CO2 separation membrane on the sacrificial layer; a porous film bonding step of bonding a porous film onto the coating film; After the porous film bonding step, a sacrificial layer removing step is performed to remove the sacrificial layer. The raw material composition contains a silicon-containing resin and an organic solvent. The silicon-containing resin is a water-insoluble resin, and has a mass average molecular weight of 2,000 or more.

[0023] By producing a laminate film using such a laminate film manufacturing method, it is possible to produce a thin, large laminate film in which a CO separation membrane and a porous membrane (support substrate) are laminated and in which defects such as chips and pinholes are suppressed, as shown in the examples described below. Moreover, the above-mentioned production method is excellent in terms of continuous productivity (mass productivity) as shown in the steps constituting the above-mentioned production method.

[0024] The CO2 separation membrane in the laminated film produced has an area of, for example, 0.03 m 2 or more, and the thickness is 1 nm or more and 10,000 nm or less. The area of ​​the CO2 separation membrane is 0.05 m 2 The area of ​​the CO2 separation membrane is preferably 0.03 m 2 More than 1000m 2 Less than 0.05m is preferable. 2 More than 800m 2 Less than 0.1m is preferable. 2 More than 500m 2 The following is even more preferred: The thickness of the CO2 separation membrane is preferably 50 nm or more and 5000 nm or less, and more preferably 80 nm or more and 1000 nm or less.

[0025] When the silicon-containing resin contains polydimethylsiloxane, the method for producing the laminated film may include a curing step of curing the polydimethylsiloxane after the porous membrane bonding step and before the sacrificial layer removing step. Furthermore, the method for manufacturing a laminated film may include a sacrificial layer formation step of forming a sacrificial layer on a support of the sacrificial layer before the coating film formation step, and a support peeling step of peeling the support from the sacrificial layer after the porous film adhesion step and before the sacrificial layer removal step. Each step will be described below with reference to Fig. 1. Fig. 1 is a schematic diagram illustrating the method for producing a laminated film.

[0026] [Sacrificial layer formation process] In the sacrificial layer formation step, a sacrificial layer 2 is formed on a support 1 for the sacrificial layer 2 (FIG. 1(a)). The sacrificial layer 2 is typically formed using a sacrificial layer-forming composition. The composition for forming a sacrificial layer is not particularly limited as long as it is a composition that can form a sacrificial layer that can be removed in a subsequent sacrificial layer removal step. The composition for forming a sacrificial layer typically contains a resin and a solvent.

[0027] Examples of resins contained in the composition for forming the sacrificial layer include polyvinyl alcohol resin, dextrin, gelatin, glue, casein, shellac, gum arabic, starch, protein, polyacrylic acid amide, sodium polyacrylate, polyvinyl methyl ether, a copolymer of methyl vinyl ether and maleic anhydride, a copolymer of vinyl acetate and itaconic acid, polyvinylpyrrolidone, acetyl cellulose, acetyl butyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, sodium alginate, and the like.

[0028] The amount of resin contained in the composition for forming a sacrificial layer is not particularly limited as long as it does not impair the object of the present invention, and is appropriately determined taking into consideration the coatability of the composition for forming a sacrificial layer, etc. When the mass of the resin in the composition for forming a sacrificial layer is 100 parts by mass, the amount of the 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.

[0029] The solvent contained in the composition for forming a sacrificial layer is not particularly limited as long as the resin is soluble in the solvent. As long as a predetermined amount of the resin is dissolved in the composition for forming a sacrificial layer, the composition for forming a sacrificial layer may contain the resin in an undissolved state. It is preferable that the resin is completely dissolved in the composition for forming a sacrificial layer.

[0030] The solvent may be water, an organic solvent, or an aqueous solution of an organic solvent.

[0031] Specific examples of organic solvents used as the solvent 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 monoalcohol solvents such as hexane, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-pentadecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, methyl isobutyl carbinol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethylcarbinol, diacetone alcohol, and cresol; 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; Lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone; Imidazolidinones such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone; dialkyl glycol ethers such as dimethyl glycol, dimethyl diglycol, dimethyl triglycol, methyl ethyl diglycol, diethyl glycol, and triethylene glycol butyl methyl ether; (poly)alkylene glycol monoalkyl ethers such as 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; (poly)alkylene glycol monoalkyl ether acetates such as 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, and propylene glycol monoethyl ether acetate; Other ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisoamyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran, etc.; Ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone; Lactic acid alkyl esters such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; other esters such as ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl formate, i-pentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, and ethyl 2-oxobutanoate; Lactones such as β-propylolactone, γ-butyrolactone, and δ-pentyrolactone; Linear, 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 p-menthane, diphenylmenthane, limonene, terpinene, bornane, norbornane, and pinane;

[0032] When the solvent is a mixed solvent 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.

[0033] The composition for forming a sacrificial layer may contain various components other than the resin and the solvent, as long as the purpose of the present invention is not impaired. Examples of the other components include a viscosity modifier, a surfactant, and a defoaming agent.

[0034] The method for preparing the composition for forming a sacrificial layer is not particularly limited. The composition for forming a sacrificial layer is typically prepared by uniformly mixing predetermined amounts of a resin, a solvent, and other components to be contained as necessary.

[0035] Examples of the support 1 that supports the sacrificial layer 2 include a resin film such as a PET (polyethylene terephthalate) film, and a substrate such as a silicon substrate or a glass substrate. In the support 1, the surface on which the sacrificial layer 2 is formed may or may not be treated with a release agent. The shape of the support 1 is not particularly limited, and may be a film or a plate. When the support is in the form of a film, a film pulled out from a film roll can be used as the support 1.

[0036] The method for forming the sacrificial layer 2 on the support 1 using a composition for forming a sacrificial layer is not particularly limited, and examples of the method include coating methods such as bar coating, slit die coating, gravure coating, spin coating, spraying, roller coating, and dipping.

[0037] After the composition for forming a sacrificial layer is applied to the support 1, the applied film of the composition for forming a sacrificial layer may be heated (dried) as necessary to remove at least a portion of the solvent of the composition for forming a sacrificial layer. The heating temperature of the coating film of the composition for forming a sacrificial layer is, for example, 50° C. or more and 90° C. or less. In addition, the coating film may be heated at a low temperature (for example, 50° C. or more and less than 70° C.) and then heated at a high temperature (for example, 70° C. or more and 90° C. or less).

[0038] The film thickness of the sacrificial layer 2 is not particularly limited, but is preferably from 1 μm to 20 μm, more preferably from 3 μm to 18 μm, and further preferably from 5 μm to 15 μm.

[0039] [Coating film formation process] In the coating film forming step, a coating film 3a of a raw material composition (a coating film forming composition) containing raw materials of the CO2 separation membrane is formed on the sacrificial layer 2 (FIG. 1(b)). The raw material composition (composition for forming a CO2 separation membrane) contains a silicon-containing resin and an organic solvent. The silicon-containing resin is a water-insoluble resin, and has a mass average molecular weight of 2,000 or more. A water-insoluble resin is a resin that dissolves at a rate of only 1.0 g or less in 100 g of water at 25°C.

[0040] Examples of the silicon-containing resin include silicone resins (resins having siloxane bonds in the main skeleton). As the silicone resin, polyorganosiloxanes such as polydimethylsiloxane, polyphenylmethylsiloxane, and polydiphenylsiloxane are preferred, and polydimethylsiloxane is more preferred. The polyorganosiloxane may be used together with a curing agent for the polyorganosiloxane. The silicon-containing resin may have hydroxyl groups at both ends or one end of the molecular chain. The silicon-containing resin may also be an elastomer.

[0041] The mass average molecular weight Mw of the silicon-containing resin is 2,000 or more, preferably 2,200 or more and 200,000 or less, and more preferably 2,500 or more and 120,000 or less. In this specification, the mass average molecular weight Mw can be defined as a relative value calculated in terms of polystyrene in a GPC (gel permeation chromatography) measurement.

[0042] The curing agent contained in the raw material composition together with the polyorganosiloxane is a curing agent that cures the polyorganosiloxane. Examples of the curing agent include alkoxysilanes such as tetramethoxysilane, trimethoxymethylsilane, dimethoxydimethylsilane, methoxytrimethylsilane, and γ-glycidoxypropyltrimethoxysilane.

[0043] 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 1 part by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the polyorganosiloxane.

[0044] Examples of the solvent contained in the raw material composition include sulfoxides, sulfones, amides, lactams, imidazolidinones, 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, and terpenes. The sulfoxides include dimethyl sulfoxide. Examples of sulfones include dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone. Examples of amides include N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide. 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. Examples of imidazolidinones include 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone. Examples of dialkyl glycol ethers include dimethyl glycol, dimethyl diglycol, dimethyl triglycol, methyl ethyl diglycol, diethyl glycol, and triethylene glycol butyl methyl ether. 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. Examples of the (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. Examples of other ethers include dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisoamyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and tetrahydrofuran. Examples of ketones include methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, and 2,6-dimethyl-4-heptanone. Other esters include, for example, 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 ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxy-1-butyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, and acetic acid. Examples of the ethyl acetate include n-propyl, 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 n-octanoate, methyl decanoate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutanoate, dimethyl adipate, and propylene glycol diacetate. Examples of lactones include propylolactone, γ-butyrolactone, and 6-pentyrolactone. Examples of linear, branched, or cyclic aliphatic hydrocarbons include n-hexane, n-heptane, n-octane, n-nonane, methyloctane, n-decane, n-pentane, n-dodecane, 2,2,4,6,6-pentamethylheptane, 2,2,4,4,6,8,8-heptamethylnonane, cyclohexane, and methylcyclohexane. Examples of aromatic hydrocarbons include benzene, toluene, benzotrifluoride, xylene, 1,3,5-trimethylbenzene, naphthalene, and decahydronaphthalene. Examples of terpenes include p-menthane, diphenylmenthane, limonene, terpinene, bornane, norbornane, and pinane.

[0045] 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. The solid content concentration of the raw material composition is preferably from 1% by mass to 20% by mass, more preferably from 3% by mass to 18% by mass, and even more preferably from 5% by mass to 15% by mass.

[0046] The method for preparing the raw material composition is not particularly limited. The raw material composition is typically prepared by uniformly mixing a silicon-containing resin, a solvent, and a curing agent, which is optionally contained, and the like.

[0047] After the raw material composition is applied onto the sacrificial layer 2, the applied film may be heated (dried) as necessary to remove at least a part of the solvent of the film-forming composition. The heating (drying) temperature of the coating film is, for example, 40° C. or higher and 60° C. or lower. The heating (drying) time for the coating film is, for example, from 0.5 minutes to 1 minute.

[0048] [Porous membrane adhesion process] In the porous membrane bonding step, a porous membrane 4, which is a support substrate for the CO2 separation membrane, is bonded onto the coating membrane 3a (FIG. 1(c)). The CO2 separation membrane is formed from the coating membrane 3a. When the CO2 separation membrane is thin or large, it is difficult for the CO2 separation membrane to stand on its own, and it is prone to deformation and breakage. By bonding the porous membrane 4 that supports (reinforces) the CO2 separation membrane, deformation and breakage can be suppressed and the functions such as the separation performance of the CO2 separation membrane can be maintained.

[0049] The pore size of the porous membrane 4 is preferably 1 mm or less, more preferably 1 nm or more and 10,000 nm or less, and further preferably 10 nm or more and 5,000 nm or less. The pore size (average pore size) of the porous membrane 4 can be measured by measuring the pore size distribution using a through-hole pore size evaluation device based on the ASTM F316-86 (JIS K 3832) bubble point method. An example of a porometer (through-hole pore size distribution measurement device) used for the measurement is the Nanoperm Porometer manufactured by Seika Digital Image Co., Ltd.

[0050] The material of the porous film 4 may be an organic material or an inorganic material, but an organic material is preferable. Such an organic material is typically a resin. Examples of the resin include polyacetal, polyamide, polycarbonate, polyester (polybutylene terephthalate, polyethylene terephthalate, polyarylate, etc.), FR-AS resin, FR-ABS resin, AS resin, ABS resin, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, fluorine-based resin (polytetrafluoroethylene, polyvinylidene fluoride, etc.), polyimide, polyamideimide, 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. Among resins, polyvinylidene fluoride, polyethersulfone, polyimide, and polyamideimide are preferred because they are thermally and chemically stable and can easily produce membranes with excellent mechanical strength. Do is preferred. As the material for the porous membrane, a mixture of two or more resins may be used. The porous membrane 4 has a film shape. A film pulled out from a film roll can be used as the porous membrane 4.

[0051] The thickness of the porous membrane 4 is not particularly limited, but is preferably from 1 μm to 100 μm, more preferably from 10 μm to 80 μm, and even more preferably from 20 μm to 60 μm.

[0052] The method for adhering the porous film 4 onto the coating film 3a is not particularly limited. For example, lamination, a transfer method using intermolecular forces, etc. can be used. The coating film 3a and the porous film 4 can be adhered to each other without using an adhesive. For example, the membrane 3 may be laminated (thermocompression bonded) to the porous membrane 4 using a roll 11 or the like, with a pressure that does not damage the porous membrane 4. The conditions for thermocompression bonding are: roller pressure of 0.1 kgf / cm 2 More than 10kgf / cm 2 Less than 0.2kgf / cm is preferable. 2 More than 5kgf / cm 2 The temperature of the roller is preferably 20° C. or higher and 120° C. or lower, and more preferably 25° C. or higher and 100° C. or lower. When intermolecular forces are utilized, for example, the coating film 3a and the porous film 4 may be brought into contact with each other.

[0053] [Curing process] When the raw material composition for forming the coating film in the coating film forming step contains polydimethylsiloxane as the silicon-containing resin, a curing step of curing the polydimethylsiloxane may be included after the porous film bonding step and before the sacrificial layer removal step. In the curing step, the coating film is cured to become a cured film (CO2 separation membrane 3). When the curing step is not included, the coating film 3a may be the CO2 separation membrane 3.

[0054] The curing method includes heating the coating film. The solvent may be removed during the heating in the curing step. The heating temperature of the coating film is, for example, 100°C or higher and 160°C or lower, and preferably 105°C or higher and 150°C or lower. The heating time for the coating film is, for example, from 1 minute to 10 minutes, and preferably from 2 minutes to 5 minutes.

[0055] [Support peeling process] In the support peeling step, the support 1 is peeled off from the sacrificial layer 2 (FIG. 1(d)). The method for peeling the support 1 from the sacrificial layer 2 is not particularly limited. Examples include a method in which the support 1 is peeled off from the sacrificial layer 2 without using a peeling liquid or the like. When the support 1 is in the form of a film, the support 1 can be peeled off from the sacrificial layer 2 by unwinding the film. When the support 1 is peeled off from the sacrificial layer 2, a part of the sacrificial layer 2 may be peeled off together with the support 1.

[0056] [Sacrificial layer removal process] In the sacrificial layer removal process, the sacrificial layer 2 is removed (Figure 1(e)). This produces a laminated film 10 in which a CO2 separation membrane 3 and a porous membrane 4 are laminated (Figure 1(f)). The laminated film 10 may be dried using an airflow or a dryer, etc., if necessary.

[0057] The sacrificial layer 2 is typically removed by dissolving the sacrificial layer 2 in a liquid. The liquid for dissolving the sacrificial layer 2 may be water, an organic solvent, or a mixed solvent of water and an organic solvent. When dissolving the sacrificial layer with these liquids, a part of the sacrificial layer may remain without being dissolved in the liquid. In order to remove the remaining sacrificial layer, it is preferable to further dissolve the sacrificial layer using, for example, an alkaline aqueous solution (basic aqueous solution).

[0058] The method for dissolving the sacrificial layer 2 in liquid is not particularly limited, but examples include washing the sacrificial layer 2 with running water, immersing the sacrificial layer 2 in liquid, or spraying the sacrificial layer 2 with liquid from a shower. The time for washing the sacrificial layer 2 with running water is not particularly limited, but is, for example, from 1 minute to 30 minutes. The time for which the sacrificial layer 2 is immersed in the liquid is not particularly limited, but is, for example, from 5 minutes to 120 minutes. The time for spraying the liquid onto the sacrificial layer 2 is not particularly limited, but is, for example, from 2 minutes to 5 minutes. The temperature of the liquid is not particularly limited, but may be, for example, 10°C or higher and 40°C or lower, and may be 20°C or higher and 30°C or lower.

[0059] <Laminated film> The laminated film is a laminated film in which a CO2 separation membrane and a porous membrane that is a support substrate for the CO2 separation membrane are laminated. The CO2 separation membrane has an area of ​​0.03 m 2 The thickness of the CO2 separation membrane is 1 nm or more and 10,000 nm or less. The area of ​​the CO2 separation membrane is 0.05 m 2 The area of ​​the CO2 separation membrane is preferably 0.03 m 2 More than 1000m 2 Less than 0.05m is preferable. 2 More than 800m 2 Less than 0.1m is preferable. 2 More than 500m 2 The thickness of the CO2 separation membrane is preferably 50 nm or more and 5000 nm or less, and more preferably 80 nm or more and 1000 nm or less. Although such a laminate film has been difficult to produce in the past, it can be produced by the above-mentioned laminate film production method. The shape of the laminate film is not particularly limited. From the viewpoint of ease of handling, the laminate film is preferably a film roll wound in a roll shape.

[0060] ≪CO2 separation method≫ The CO2 separation method includes a separation step of supplying a gas containing CO2 to the laminated film described above, thereby separating CO2 from the gas. The laminated film described above has a thin and large CO2 separation membrane with reduced defects, and therefore can perform a large amount of CO2 separation processing with high performance. By using such a CO2 separation method, it is possible to prevent global warming caused by CO2 by separating and capturing the CO2. In addition, the captured CO2 can be used as a carbon resource. EXAMPLES

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0062] [Example] <Preparation of raw material composition (coating film forming composition)> 100 parts by mass of PDMS elastomer (mass average molecular weight Mn2500) and 10 parts by mass of a curing agent for PDMS elastomer were dissolved in decahydronaphthalene so that the PDMS elastomer concentration was 5% by mass, to prepare a raw material composition (coating film forming composition). The viscosity of the obtained raw material composition was 20 cp at 24°C.

[0063] <Manufacturing of laminated film> First, a 10% by mass ethanol solution of polyvinyl alcohol serving as a sacrificial layer-forming composition was applied onto a support (PET film) 1 by gravure coating to form a sacrificial layer 2 having a thickness of 15 μm.

[0064] Next, a raw material composition (coating film forming composition) was applied in the form of a layer on the sacrificial layer 2 by gravure coating, and heated at 50° C. for 0.5 minutes to form a gel-like PDMS film 3a.

[0065] Next, a supporting substrate (porous polyimide film, pore size 50 nm or more and 2500 nm or less) 4 was placed on top of the gel-like PDMS film 3a, and the supporting substrate 4 and the PDMS film 3a were brought into contact with each other using a roller, thereby bonding the supporting substrate 4 and the PDMS film 3a together by intermolecular forces.

[0066] Next, the support substrate 4 and the PDMS film 3a bonded together were heated at 110° C. for 3 minutes to crosslink (cure) the PDMS, thereby forming a cured film (CO2 separation membrane).

[0067] Next, the support (PET film) 1 was unwound at a transport speed of 0.6 m / min, thereby peeling the support 1 from the sacrificial layer 2.

[0068] After peeling off the support 1, the exposed sacrificial layer 2 was washed with running water at room temperature (25°C) for 5 minutes to obtain a laminate 10 in which the cured film (CO2 separation membrane) 3 and the supporting substrate (porous polyimide film) 4 were laminated. The film thickness of the cured film (CO2 separation membrane) 3 was 1000 nm.

[0069] By the above procedure, cured membranes (CO2 separation membranes) of various sizes were produced, and the surfaces of the cured membranes were visually observed (observation area: 5 cm square). 2 (5cm square) to size 0.05m 2 , 0.06m 2 (A4 size) or 130m 2 No defects (chips, pinholes) were observed in any of the samples, from the large ones to the large ones. When producing the small ones, the bar coating method was used instead of the gravure coating method. Therefore, it can be seen that the above-mentioned method for producing a laminated film makes it possible to produce a thin, large, and defect-suppressed laminated film in which a CO2 separation membrane and a supporting substrate (porous membrane) are laminated together.

[0070] Comparative Example 1 As a support, a silicon wafer cleaned with a piranha solution was prepared. On a support (silicon wafer), 100 μL of a 15% by mass ethanol solution of polyvinyl alcohol as a sacrificial layer-forming composition was dropped and applied by spin coating (500 rpm, 20 seconds) to form a sacrificial layer with a thickness of 15 μm.

[0071] Next, the raw material composition (coating film forming composition) prepared in Example 1 was applied in the form of a layer onto the sacrificial layer by spin coating (1000 rpm, 20 seconds), and heated on a hot plate at 120°C for 5 minutes to crosslink (cure) the PDMS and form a cured film (CO2 separation membrane).

[0072] After crosslinking, the film was left in the air to cool to room temperature, and then immersed in ethanol. At this time, cuts were made in the edges of the cured film (CO2 separation membrane) and the sacrificial layer with a design knife. After leaving it for a while, the sacrificial layer was dissolved in the ethanol, and the cured film (CO2 separation membrane) was peeled off from the support. The solvent was then removed and dried, and the cured film (CO2 separation membrane) was separated. As described above, the method of Comparative Example 1 includes steps that are unsuitable for continuous production (mass production), such as spin coating, leaving at room temperature, and making cuts with a cutting knife.

[0073] By the above procedure, cured membranes (CO2 separation membranes) of various sizes were produced, and the surfaces of the cured membranes were visually observed (observation area: 5 cm square). 2 Chips and pinholes were observed in specimens larger than 5cm square. [Explanation of symbols]

[0074] 1 Support 2 Sacrificial Layer 3a Coating film 3 Cured membrane (CO2 separation membrane) 4 Supporting base material 10 Laminated film 11 Rolls

Claims

1. CO ２ A separation membrane and the CO ２ A method for producing a laminated film in which a porous membrane that is a support substrate for a separation membrane is laminated, comprising the steps of: On the sacrificial layer, ２ A coating film forming step of forming a coating film of a raw material composition containing raw materials for the separation membrane; a porous membrane adhering step of adhering the porous membrane onto the coating membrane; A sacrificial layer removal step of removing the sacrificial layer after the porous membrane bonding step, The raw material composition includes a silicon-containing resin and an organic solvent, The silicon-containing resin is a water-insoluble resin, The method for producing a laminated film, wherein the silicon-containing resin has a mass average molecular weight of 2,000 or more.

2. The CO ２ The separation membrane has an area of ​​0.03 m ２ The method for producing a laminated film according to claim 1, wherein the thickness is 1 nm or more and 10,000 nm or less.

3. The method for producing a laminated film according to claim 1 , wherein the silicon-containing resin comprises polydimethylsiloxane.

4. The method for producing a laminated film according to claim 3 , further comprising a curing step of curing the polydimethylsiloxane after the porous membrane bonding step and before the sacrificial layer removing step.

5. The method for producing a laminated film according to claim 1 , wherein the porous film is a porous film made of polyimide.

6. The method for producing a laminated film according to claim 1 , wherein the porous film has a pore size of 1 mm or less.

7. a sacrificial layer forming step of forming the sacrificial layer on a support of the sacrificial layer before the coating film forming step; The method for producing a laminated film according to any one of claims 1 to 6, further comprising: a support peeling step of peeling the support from the sacrificial layer after the porous membrane bonding step and before the sacrificial layer removing step.

8. The method for producing a laminated film according to claim 7, wherein the support is a film made of polyethylene terephthalate.

9. The method for producing a laminated film according to claim 1 , wherein the laminated film is a wound film roll.

10. CO ２ A separation membrane and the CO ２ A laminated film in which a porous membrane which is a support substrate for a separation membrane is laminated, The CO ２ The separation membrane has an area of ​​0.03 m ２ The laminate film has a thickness of 1 nm or more and 10,000 nm or less.

11. The laminated film according to claim 10, which is a film roll wound in a roll shape.

12. The laminated film according to claim 10 or 11 is ２ By supplying a gas containing ２ A separation step of separating CO ２ Separation method.

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