Film-forming composition, cured film, method for producing cured film, method for producing laminate, and method for separating CO2

Abstract

The present application provides a film forming composition capable of forming a film with uniform film thickness; a cured film of the film forming composition; a method for manufacturing the cured film; a method for manufacturing a laminate using the aforementioned method for manufacturing a cured film; and a CO2 separation method using a laminate manufactured using the aforementioned method for manufacturing a laminate. A film forming composition is provided, which comprises a polydimethylsiloxane, a curing agent, and at least one hydroxamic acid selected from the group consisting of hydroxamic acids and salts thereof, the content of the aforementioned hydroxamic acid being greater than 0 mass% and less than 5 mass% relative to the mass of the aforementioned polydimethylsiloxane.

Description

Technical Field

[0001] This invention relates to a membrane forming composition, a cured membrane, a method for manufacturing a cured membrane, a method for manufacturing a laminate, and a CO2 separation method. 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 The manufacture of CO2 separation membranes uses membrane forming compositions, for example, those containing polydimethylsiloxane (PDMS).

[0005] However, when the CO2 separation membrane is a thin film, the following problem exists: if a membrane forming composition containing polydimethylsiloxane as a liquid polymer is used, the polydimethylsiloxane will aggregate, resulting in unevenness in the formed membrane, making it difficult to manufacture a CO2 separation membrane with uniform thickness.

[0006] It should be noted that, not only CO2 separation membranes, other membranes manufactured using membrane forming compositions containing polydimethylsiloxane also suffer from the same problems, such as the tendency to produce unevenness on the surface of the formed membrane and the difficulty in manufacturing membranes with uniform thickness.

[0007] The present invention was made in view of the above-mentioned problems, and its object is to provide a film forming composition comprising polydimethylsiloxane and capable of forming a film with uniform film thickness; a cured film of the film forming composition; a method for manufacturing the cured film; a method for manufacturing a laminate using the aforementioned method for manufacturing the cured film; and a CO2 separation method using the laminate manufactured by the aforementioned method.

[0008] Methods for solving problems The inventors of this application discovered that the above-mentioned problems could be solved by the following film-forming composition, thereby completing the present invention. The film-forming composition comprises polydimethylsiloxane, a curing agent, and at least one isohydroxamic acid selected from isohydroxamic acid and its salts, wherein the content of the isohydroxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of the polydimethylsiloxane. Specifically, the present invention provides the following method.

[0009] [1] A film-forming composition comprising polydimethylsiloxane, a curing agent, and at least one isohydroxamic acid selected from isohydroxamic acids and their salts. The content of the aforementioned hydroxamic acids is greater than 0% by mass and less than 5% by mass relative to the mass of the aforementioned polydimethylsiloxane.

[0010] [2] The film-forming composition as described in [1] above, wherein the mass-average molecular weight of the aforementioned polydimethylsiloxane is 90,000 or more.

[0011] [3] The membrane forming composition as described in [1] or [2] above is a CO2 separation membrane forming composition.

[0012] [4] A cured film, which is a cured film formed from the cured product of the film forming composition described in any one of [1] to [3] above. The content of the aforementioned hydroxamic acids is greater than 0% by mass and less than 5% by mass relative to the mass of the aforementioned cured film.

[0013] [5] The surface roughness Ra of the cured film as described in [4] above is less than 10% of the thickness of the cured film.

[0014] [6] The cured film as described in [4] or [5] above has a thickness of more than 10 nm and less than 2000 nm.

[0015] [7] The cured membrane as described in any one of [4] to [6] above is a CO2 separation membrane.

[0016] [8] A method for manufacturing a cured film, comprising: The coating film forming process forms a coating film of the film forming composition described in any one of [1] to [3] above; and The curing process cures the aforementioned coating film to form a cured film. In the aforementioned curing process, the content of the aforementioned hydroxamic acid in the aforementioned cured film is adjusted to be greater than 0% by mass and less than 5% by mass.

[0017] [9] The method for manufacturing a cured membrane as described in [8] above, wherein the cured membrane is a CO2 separation membrane.

[0018]

[10] A method for manufacturing a laminate, which is a method for manufacturing a laminate obtained by laminating a CO2 separation membrane and a support substrate. The method for manufacturing the laminate includes a CO2 separation membrane manufacturing process for manufacturing the aforementioned CO2 separation membrane using the method for manufacturing the cured membrane described above [9].

[0019]

[11] CO2 separation methods, including: The laminate manufacturing process involves manufacturing a laminate using the laminate manufacturing method described above

[10] ; and In the separation process, a gas containing CO2 is supplied to the aforementioned laminate to separate CO2 from the aforementioned gas.

[0020] Invention Effects According to the present invention, a film-forming composition comprising polydimethylsiloxane and capable of forming a film with uniform film thickness can be provided; a cured film of the film-forming composition; a method for manufacturing the cured film; a method for manufacturing a laminate using the aforementioned method for manufacturing the cured film; and a CO2 separation method using the laminate manufactured by the manufacturing method. Attached Figure Description

[0021] [ Figure 1 This is a schematic diagram illustrating the manufacturing method of a laminated body.

[0022] [ Figure 2 [A photograph showing the observation results of Comparative Example 1.]

[0023] [ Figure 3 [Photograph showing the observation results of Comparative Example 2]

[0024] [ Figure 4 [Photograph showing the observation results of Comparative Example 3]

[0025] [ Figure 5 [A photograph showing the observation results of Example 1.]

[0026] [ Figure 6 [Graphs showing the measurement results of film thickness and surface roughness Ra in Examples 2-4.] Detailed Implementation

[0027] Compositions for film formation The film-forming composition comprises polydimethylsiloxane, a curing agent, and at least one isohydroxamic acid selected from isohydroxamic acids and their salts.

[0028] In the film-forming composition, the content of isohydroxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of polydimethylsiloxane.

[0029] By using the above-described film-forming composition, as shown in the examples described later, a film with uniform thickness can be formed compared to the case where a film-forming composition containing isohydroxamic acid content outside the above range is used.

[0030] The reason why a film with uniform thickness can be formed by using the above-described film-forming composition is not yet clear, but it is speculated to be due to the following reasons.

[0031] If the film-forming composition contains trace amounts (greater than 0% by mass and less than 5% by mass) of phenylisohydroxyoxime acids, the polydimethylsiloxane in the film-forming composition will undergo molecular weight increase during film formation (curing of the film). This inhibits the aggregation of polydimethylsiloxane, resulting in a film that is less prone to unevenness (e.g., becomes a smooth film), and a film with uniform thickness can be obtained.

[0032] The membrane thickness is uniform, so when the formed membrane is used as a separation membrane such as a CO2 separation membrane, the separation performance can be uniform throughout the entire separation membrane.

[0033] On the other hand, if the composition for forming the membrane does not contain trace amounts (greater than 0% by mass and less than 5% by mass) of phenyl isohydroxamic acid, polydimethylsiloxane aggregates, and unevenness is easily generated in the formed membrane, making it difficult to obtain a membrane with uniform thickness.

[0034] When the formed film is a thin film, if a film-forming composition containing polydimethylsiloxane as a liquid polymer is used, the polydimethylsiloxane will aggregate, resulting in unevenness in the formed film and making it difficult to manufacture a film with uniform thickness. However, by using the film-forming composition described above, even for thin films (e.g., 10 nm to 2000 nm), uniform film thickness can be achieved.

[0035] In the membrane-forming composition, the content of isohydroxamic acids is only required to be greater than 0% by mass and less than 5% by mass relative to the mass of polydimethylsiloxane, preferably 0.05% by mass or more than 4% by mass, and more preferably 1% by mass or more than 3% by mass. That is, in the membrane-forming composition, the ratio of (mass of isohydroxamic acids) to (mass of polydimethylsiloxane) × 100 is only required to be greater than 0 and less than 5, preferably 0.05% by mass or more than 4%, and more preferably 1% by mass or more than 3%.

[0036] The isohydroxamic acid contained in the film-forming composition is at least one selected from isohydroxamic acids and their salts.

[0037] Examples of isohydroxamic acids include phenyl isohydroxamic acid (N-hydroxybenzamide), 1-naphthyl isohydroxamic acid, and salicylic isohydroxamic acid.

[0038] Examples of hydroxamic acid salts include sodium salts of phenylhydroxamic acid, such as sodium phenylhydroxamic acid.

[0039] The polydimethylsiloxane contained in the film-forming composition may also have hydroxyl groups at both ends or one end of the molecular chain.

[0040] In addition, the polydimethylsiloxane contained in the film-forming composition may also be an elastomer.

[0041] The mass-average molecular weight (Mw) of the polydimethylsiloxane contained in the film-forming composition is preferably 90,000 or more, more preferably 95,000 or more, and even more preferably 100,000 or more.

[0042] Furthermore, the dispersion of polydimethylsiloxane (weight-average molecular weight Mw / number-average molecular weight Mn) is preferably 1 to 20, more preferably 3 to 15, and even more preferably 5 to 10.

[0043] It should be noted that in this specification, the mass-average molecular weight Mw and number-average molecular weight Mn can be defined as relative values ​​converted to polystyrene in GPC (gel permeation chromatography) determination.

[0044] The content of polydimethylsiloxane in the film-forming composition is not particularly limited. The content of polydimethylsiloxane in the film-forming 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.

[0045] The curing agent contained in the film-forming composition is a curing agent that cures polydimethylsiloxane.

[0046] Examples of curing agents include alkoxysilanes such as tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methoxytrimethylsilane, and γ-glycidyl etheroxypropyltrimethoxysilane.

[0047] The content of the curing agent in the film-forming composition is not particularly limited. In the film-forming composition, the content of the curing agent is preferably 0.1 parts by mass or more to 20 parts by mass relative to 100 parts by mass of polydimethylsiloxane, more preferably 1 part by mass or more to 10 parts by mass or less.

[0048] The film-forming composition may also contain a solvent.

[0049] The boiling point of the solvent is not particularly limited, but is preferably 70°C to 300°C, more preferably 80°C to 250°C, and even more preferably 90°C to 200°C.

[0050] Examples of solvents included in the film-forming 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.

[0051] Dimethyl sulfoxide (DMSO) is an example of a sulfoxide.

[0052] Examples of sulfones include dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone.

[0053] Examples of amides include N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide.

[0054] 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.

[0055] Examples of imidazolinones include 1,3-dimethyl-2-imidazolinone, 1,3-diethyl-2-imidazolinone, and 1,3-diisopropyl-2-imidazolinone.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Examples of ketones include methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, and 2,6-dimethyl-4-heptanone.

[0061] 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.

[0062] Examples of lactones include propiolactone, γ-butyrolactone, and 6-pentanolactone.

[0063] 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.

[0064] Examples of aromatic hydrocarbons include benzene, toluene, trifluorotoluene, xylene, 1,3,5-trimethylbenzene, naphthalene, and decahydronaphthalene.

[0065] Examples of terpenoids include p-menthane, diphenylmenthane, limonene, terpinene, camphene, norbornene, and pinane.

[0066] There are no particular limitations on the method for preparing the film-forming composition. Typically, the film-forming composition can be prepared by uniformly mixing polydimethylsiloxane, a curing agent, isohydroxamic acid, a solvent, and other components as needed.

[0067] "Cured Film" The cured film is formed from the cured product of the above-mentioned film-forming composition.

[0068] Regarding the cured film, the content of isohydroxamic acids is greater than 0% by mass and less than 5% by mass relative to the mass of the cured film.

[0069] Therefore, the cured film includes a cured product obtained by curing polydimethylsiloxane with a curing agent, and isohydroxamic acids, the content of which is greater than 0% by mass and less than 5% by mass relative to the mass of the cured film.

[0070] As shown in the examples described later, such cured films have a more uniform thickness compared to cured films with hydroxamic acid content outside the aforementioned range.

[0071] For example, the surface roughness Ra of the cured film is less than 10% of the film thickness. It should be noted that the surface roughness Ra is a value specified by JIS B 0601 (1994).

[0072] In the cured film, the content of isohydroxamic acid is only required to be greater than 0% by mass and less than 5% by mass relative to the mass of the cured film, preferably 0.01% by mass or more than 4% by mass, and more preferably 1% by mass or more than 2% by mass.

[0073] There is no limit to the thickness of the cured film. For example, a cured film can be a thin film with a thickness of 10 nm to 2000 nm. The thickness of the cured film can also be less than 1000 nm, less than 500 nm, or less than 200 nm.

[0074] There is no limitation on the size of the cured film. For example, the cured film can also be 0.03 m² in area. 2 Above (e.g., 0.03m) 2 Above 1000m 2 Large membranes (see below).

[0075] The thickness of the cured membrane is uniform. Therefore, if the cured membrane is used as a separation membrane such as a CO2 separation membrane, the separation performance is uniform throughout the membrane.

[0076] Manufacturing Method of Cured Film The aforementioned cured film can be manufactured, for example, using the following method for manufacturing a cured film, which includes: a coating film forming step to form a coating film of the above-mentioned film forming composition; and a curing step to cure the coating film to form a cured film.

[0077] As a method for manufacturing a cured film, in the curing process, the content of isohydroxamic acid in the cured film is adjusted to be greater than 0% by mass and less than 5% by mass.

[0078] The following describes each process.

[0079] [Coating film formation process] In the coating film forming process, a coating film of the above-mentioned film forming composition is formed.

[0080] There are no particular limitations on the method for forming the coated film. Examples of methods include rod coating, die coating, gravure coating, spin coating, spray coating, roller coating, and dip coating. When forming large films, gravure coating methods such as micro-gravure coating with gravure rollers are preferred.

[0081] [Curing Process] During the curing process, the coated film is cured to form a cured film.

[0082] During the curing process, the content of isohydroxamic acids in the cured film is adjusted to be greater than 0% by mass and less than 5% by mass.

[0083] Heating the coating film is one example of a method for curing the coating film.

[0084] The heating (drying) temperature of the coating film is, for example, 50°C or higher and 160°C or lower, preferably 80°C or higher and 150°C or lower, and more preferably 110°C or higher and 140°C or lower.

[0085] In addition, the heating (drying) time of the coating film is, for example, 5 minutes or more and 120 minutes or less, preferably 10 minutes or more and 60 minutes or less, and more preferably 15 minutes or more and 30 minutes or less.

[0086] The film-forming composition includes isohydroxamic acids, solvents, etc., therefore the coated film also includes isohydroxamic acids, solvents, etc. During the curing process, isohydroxamic acids, solvents, etc., decompose or volatilize, and the content ratio of isohydroxamic acids may change. On the other hand, for the cured film formed by the above-described method for manufacturing a cured film, the content of isohydroxamic acids is greater than 0% by mass and less than 5% by mass relative to the mass of the cured film. Therefore, during the curing process, the content of isohydroxamic acids in the cured film is adjusted to be greater than 0% by mass and less than 5% by mass.

[0087] The content of isohydroxamic acids in the cured film can be adjusted, for example, by adjusting the heating temperature and heating time.

[0088] The cured membrane manufactured using this method has a uniform thickness, so if used as a separation membrane such as a CO2 separation membrane, it can achieve uniform separation performance throughout the entire separation membrane.

[0089] Manufacturing Method of Laminated Materials The method for manufacturing the laminate is a method for manufacturing a laminate obtained by laminating a CO2 separation membrane and a support substrate.

[0090] The method for manufacturing the laminate includes a CO2 separation membrane manufacturing step that uses the above-described method for manufacturing a cured membrane to manufacture a CO2 separation membrane.

[0091] Regarding the manufacturing method of the laminate, for example, when the supporting substrate is a porous material, it preferably includes: In the sacrificial layer forming process, a sacrificial layer is formed on a support using a sacrificial layer forming composition; In the CO2 separation membrane manufacturing process, the CO2 separation membrane is manufactured on the sacrificial layer using the above-mentioned method for manufacturing a cured membrane. The bonding process involves bonding a support substrate onto the CO2 separation membrane. The peeling process involves peeling the support after the bonding process; and The sacrificial layer removal process involves dissolving the sacrificial layer in a liquid after the stripping process, thereby removing the sacrificial layer.

[0092] For each process, the following is used Figure 1 Please provide an explanation. Figure 1 This is a schematic diagram illustrating the manufacturing method of a laminated body.

[0093] [Sacrificial layer formation process] In the sacrificial layer formation process, a sacrificial layer 2 is formed on the support 1 using a sacrificial layer formation composition. Figure 1 (a)).

[0094] 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.

[0095] 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.

[0096] The amount of resin contained in the sacrificial layer forming composition is not particularly limited without hindering the purpose of the present invention, and can be appropriately determined by taking into account factors such as the coatability of the sacrificial layer forming composition. Typically, the amount of resin in the sacrificial layer forming composition is preferably such that the relationship between the amount of resin in the sacrificial layer forming composition and the amount of solvent described later is as follows.

[0097] 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.

[0098] 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.

[0099] The solvent can be water, an organic solvent, or an aqueous solution of an organic solvent.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] Examples of supports 1 used to form the sacrificial layer 2 using such a sacrificial layer forming composition include resin films such as PET (polyethylene terephthalate) films, silicon substrates, glass substrates, and other substrates. The surface of the support 1 where the sacrificial layer 2 is to be formed may be treated with a release agent or left untreated.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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).

[0109] 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.

[0110] [CO2 Separation Membrane Manufacturing Process] In the CO2 separation membrane manufacturing process, the CO2 separation membrane 3 is formed on the sacrificial layer 2 using the above-mentioned method for manufacturing a cured membrane. Figure 1 (b)

[0111] [Adhesion process] In the bonding process, the supporting substrate 4 is bonded to the CO2 separation membrane 3. Figure 1 (c)).

[0112] In the case of a thin film or a large membrane, the CO2 separation membrane 3 alone is difficult to self-support and is prone to deformation and breakage. By bonding a support substrate 4 that supports (reinforces) the CO2 separation membrane 3 to the CO2 separation membrane 3, deformation and breakage can be suppressed, and functions such as the separation performance of the CO2 separation membrane 3 can be maintained.

[0113] The material used as the supporting substrate 4 can be either an organic or inorganic material, but is preferably an organic material. Typically, this organic material is a resin.

[0114] 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.

[0115] 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.

[0116] As a membrane material, two or more resins can also be mixed and used.

[0117] The support substrate 4 is preferably a porous material that allows gas to pass through.

[0118] The shape of the support substrate 4 is not particularly limited; it can be either a film or a plate. If the support substrate is in the form of a film, a film drawn from a film roll can be used as the support substrate 4.

[0119] The thickness of the support substrate 4 is not particularly limited, but is preferably 1 μm to 100 μm, more preferably 10 μm to 80 μm, and even more preferably 20 μm to 60 μm.

[0120] There are no particular limitations on the method for bonding the support substrate 4 to the CO2 separation membrane 3. Examples include lamination and transfer methods that utilize intermolecular forces.

[0121] For example, a roller 11 or similar device can be used to apply pressure to the support substrate 4 such that it does not cause damage, thereby laminating (hot-pressing) the CO2 separation membrane 3 onto the support substrate 4. Regarding the hot-pressing conditions, the roller pressure is preferably 0.1 kgf / cm². 2 Above 10 kgf / cm2 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.

[0122] In the case of utilizing intermolecular forces, for example, it is sufficient to use a roller to bring the CO2 separation membrane 3 into contact with the supporting substrate 4.

[0123] [Stripping Process] In the peeling process, the support 1 is peeled off after the bonding process. Figure 1 (d)

[0124] 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. For example, if the support 1 is in the form of a film, the support 1 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.

[0125] [Sacrificial layer removal process] In the sacrificial layer removal process, after the stripping process, sacrificial layer 2 is dissolved in liquid to remove sacrificial layer 2. Figure 1 (e)). Thus, it is possible to manufacture a laminate 10 obtained by laminating the CO2 separation membrane 3 and the support substrate 4. Figure 1 (f)). The laminate 10 can also be dried using airflow, dryer, etc., as needed.

[0126] 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.

[0127] 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.

[0128] CO2 Separation Methods The CO2 separation method includes: a laminate manufacturing step, which manufactures a laminate obtained by laminating a CO2 separation membrane and a support substrate using the above-described laminate manufacturing method; and a separation step, which supplies a gas containing CO2 to the laminate to separate CO2 from the gas.

[0129] By using such CO2 separation methods to separate and recover CO2, it is possible to mitigate global warming caused by CO2.

[0130] In addition, the recovered CO2 can be utilized as a carbon resource.

[0131] 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.

[0132] [Example 1] <Preparation of Compositions for Membrane Formation> A film-forming composition was prepared by dissolving 88.5 parts by weight of PDMS elastomer with terminal hydroxyl groups (weight-average molecular weight Mn = 106400, dispersity Mw / Mn = 6.29), 8.9 parts by weight of methyltrimethoxysilane, and 2.6 parts by weight of phenylhydroxamic acid in a solvent to achieve a PDMS elastomer concentration of 5% by weight. It should be noted that heptane (boiling point 98°C), butyl acetate (boiling point 126°C), and decahydronaphthalene (boiling point 185°C) were used as solvents to prepare the film-forming composition separately.

[0133] Manufacturing of Cured Membranes (CO2 Separation Membranes) First, 10 μL of a 10% by mass ethanol solution of polyvinyl alcohol, which is a sacrificial layer forming composition, is dropped onto the support (PET film). The sacrificial layer forming composition dropped onto the support 1 is then coated onto the support 1 using a rod coating method to form a sacrificial layer with a film thickness of 15 μm (sacrificial layer forming step).

[0134] Next, the membrane forming composition is coated in layers onto the sacrificial layer using a rod coating method, and heated at 120°C for 20 minutes using a heating plate to form a cured membrane (CO2 separation membrane) with a thickness of 1000 nm (membrane forming process).

[0135] [Comparative Example 1] Instead of the above-described <Preparation of the Composition for Film Formation>, the composition for film formation is prepared using the following method, except that the same operation as in Example 1 is performed.

[0136] A film-forming composition was prepared by dissolving SYLGARD 184 (manufactured by Dow Corning Corp., polydimethylsiloxane (weight-average molecular weight Mn=19500, dispersity Mw / Mn=4.14), PDMS:curing agent=10:1) in a solvent at a PDMS concentration of 5% by mass. It should be noted that heptane (boiling point 98°C), butyl acetate (boiling point 126°C), and decahydronaphthalene (boiling point 185°C) were used as solvents, and film-forming compositions were prepared separately with each solvent.

[0137] [Comparative Example 2] In the above <Preparation of the Composition for Film Formation>, instead of 88.5 parts by mass of PDMS elastomer with terminal hydroxyl groups (weight-average molecular weight Mn=106400, dispersity Mw / Mn=6.29), 8.9 parts by mass of methyltrimethoxysilane, and 2.6 parts by mass of phenylhydroxamic acid, 90 parts by mass of PDMS elastomer with terminal hydroxyl groups (weight-average molecular weight Mn=52700, Mw / Mn=2.82) and 10 parts by mass of methyltrimethoxysilane were used, and the same operation as in Example 1 was performed.

[0138] [Comparative Example 3] In the above <Preparation of the Composition for Film Formation>, instead of 88.5 parts by mass of PDMS elastomer with terminal hydroxyl groups (weight-average molecular weight Mn=106400, dispersity Mw / Mn=6.29), 8.9 parts by mass of methyltrimethoxysilane, and 2.6 parts by mass of phenylhydroxamic acid, 90 parts by mass of PDMS elastomer with terminal hydroxyl groups (weight-average molecular weight Mn=86900, Mw / Mn=3.73) and 10 parts by mass of methyltrimethoxysilane were used, and the same operation as in Example 1 was performed.

[0139] <Observation of the membrane surface> The surface of the cured film was observed using a digital microscope. A 20x magnification photograph is shown below. Figures 2-5 . Figure 2 A photograph showing the observation results of Comparative Example 1, Figure 3 To show the photographs illustrating the observations of Comparative Example 2, Figure 4 To show the photographs of the observations in Comparative Example 3, Figure 5 A photograph showing the observation results of Example 1. Figure 2 of (a) Figure 3 of (a) Figure 4 (a) and Figure 5 (a) shows the observation results when a film-forming composition using heptane as the solvent was used. Figure 2 of (b) Figure 3 (b) Figure 4 (b) and Figure 5 (b) shows the observation results when a film-forming composition using butyl acetate as the solvent was used. Figure 2 (c) Figure 3 (c) Figure 4 (c) and Figure 5 (c) shows the observation results when a film-forming composition using decahydronaphthalene as a solvent was used.

[0140] like Figure 5As shown, in Example 1, which used a film-forming composition comprising polydimethylsiloxane, a curing agent, and isohydroxamic acid, wherein the content of isohydroxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of polydimethylsiloxane, PDMS did not aggregate, no unevenness was observed on the film surface, the film thickness deviation was minimal, and the film thickness was uniform.

[0141] In contrast, such as Figures 2-4 As shown, in Comparative Examples 1-3, which used film-forming compositions that did not contain isohydroxamic acids, PDMS aggregated into droplets, resulting in a larger deviation in film thickness compared to Example 1.

[0142] <Determination of the content of phenyl isohydroxamic acid in membranes> The content of phenylisohydroxamic acid in the obtained cured films was determined by liquid chromatography. The results showed that the content of phenylisohydroxamic acid in the cured film of Example 1 was 1.8% by mass relative to the mass of the cured film. On the other hand, the cured films of Comparative Examples 1-3 did not contain phenylisohydroxamic acid.

[0143] [Examples 2-4] The film-forming composition prepared in Example 1 (Preparation of Film-Forming Composition) was applied in layers onto a silicon wafer using a spin coating method. The wafer was then heated at 120°C for 20 minutes to form a cured film (CO2 separation membrane) (film formation process). In Examples 2-4, the amount of film-forming composition coated onto the silicon wafer was varied, resulting in different film thicknesses for each film obtained in Examples 2-4.

[0144] <Determination of film thickness and surface roughness Ra> The cured films obtained in Examples 2-4 were used to measure the film thickness and surface roughness Ra using a Dektak XT-S (manufactured by Bruker). The measurement conditions were set as follows: measurement range 6.5 μm, length 30000 μm, measurement time 60 seconds, and probe pressure 3 mg. The results are shown below. Figure 6 .

[0145] like Figure 6 As shown, in Examples 2 to 4, which used a film-forming composition comprising polydimethylsiloxane, a curing agent, and isohydroxyxamic acid, wherein the content of isohydroxyxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of polydimethylsiloxane, the surface roughness Ra of the cured film produced was less than 10% of the film thickness, and the film thickness was uniform.

[0146] Explanation of reference numerals in the attached figures 1 Support body 2. Sacrificial Layer 3 CO2 separation membrane 4 Support substrate 10-layer stack 11 rollers

Claims

1. A film-forming composition comprising polydimethylsiloxane, a curing agent, and at least one isohydroxamic acid selected from isohydroxamic acids and their salts. The content of the isohydroxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of the polydimethylsiloxane.

2. The film-forming composition according to claim 1, wherein, The mass-average molecular weight of the polydimethylsiloxane is above 90,000.

3. The membrane forming composition as claimed in claim 1, wherein it is a CO2 separation membrane forming composition.

4. A cured film, which is a cured film formed from the cured product of the film-forming composition according to any one of claims 1 to 3. The content of the isohydroxamic acid is greater than 0% by mass and less than 5% by mass relative to the mass of the cured film.

5. The cured film as described in claim 4, wherein the surface roughness Ra is less than 10% of the thickness of the cured film.

6. The cured film as described in claim 4, wherein the film thickness is 10 nm or more and 2000 nm or less.

7. The cured membrane as described in claim 4 is a CO2 separation membrane.

8. A method for manufacturing a cured film, comprising: The coating film forming process forms a coating film of the film forming composition according to any one of claims 1 to 3; and The curing process causes the coated film to solidify, forming a cured film. In the curing process, the content of isohydroxamic acid in the cured film is adjusted to be greater than 0% by mass and less than 5% by mass.

9. The method for manufacturing the cured film as described in claim 8, wherein, The cured membrane is a CO2 separation membrane.

10. A method for manufacturing a laminate, which is a method for manufacturing a laminate obtained by laminating a CO2 separation membrane and a support substrate, the method for manufacturing the laminate includes a CO2 separation membrane manufacturing step of manufacturing the CO2 separation membrane using the method for manufacturing a curing membrane according to claim 9.

11. CO2 separation methods, including: The laminate manufacturing process utilizes the laminate manufacturing method described in claim 10 to manufacture the laminate; and In the separation process, a gas containing CO2 is supplied to the laminate, thereby separating CO2 from the gas.

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