Separation function layer and separation membrane

Abstract

A separation function layer 1 according to the present invention contains a reaction product of compounds, the compounds including: a compound A that has at least one ether structure a represented by formula (a), and has a carbon-carbon unsaturated bond; and a compound B that has an Si-H group. In the formula (a), R1a represents a divalent hydrocarbon group, wherein when the compound A has a plurality of the ether structures a, a plurality of the R1a groups are independent of each other. A separation membrane 10 according to the present invention comprises: a separation function layer 1; and a porous support 3 that supports the separation function layer 1.

Description

Separation functional layer and separation membrane

[0001] This invention relates to a separation functional layer and a separation membrane.

[0002] Membrane separation is a method developed to separate acidic gases, such as carbon dioxide, from gas mixtures containing them. Compared to absorption methods, which separate acidic gases by having an absorbent absorb them, membrane separation can efficiently separate acidic gases while keeping operating costs down.

[0003] Examples of separation membranes used in membrane separation methods include composite membranes in which a separation functional layer is formed on a porous support. Polymers such as polyether block amides are used as materials for the separation functional layer (for example, Patent Document 1).

[0004] Special Publication No. 2020-532419

[0005] Conventional separation layers tend to lose separation performance when used or stored under acidic conditions.

[0006] Therefore, the present invention aims to provide a separation functional layer in which the deterioration of separation performance under acidic conditions is suppressed.

[0007] The present invention provides a separation functional layer comprising a reaction product of a group of compounds including compound A having an ether structure a represented by formula (a) and a carbon-carbon unsaturated bond, and compound B having a Si-H group. In the above formula (a), R 1a is a divalent hydrocarbon group. However, if compound A has a plurality of the ether structures a, then a plurality of R 1a They are independent of each other.

[0008] Furthermore, the present invention provides a separation membrane comprising the above-mentioned separation functional layer and a porous support that supports the separation functional layer.

[0009] According to the present invention, a separation functional layer can be provided in which the deterioration of separation performance under acidic conditions is suppressed.

[0010] This is a schematic cross-sectional view showing a separation functional layer according to one embodiment of the present invention. This is a schematic cross-sectional view showing a separation membrane according to one embodiment of the present invention. This is a schematic cross-sectional view of a membrane separation apparatus equipped with the separation membrane of the present invention. This is a schematic perspective view showing a modified example of a membrane separation apparatus equipped with the separation membrane of the present invention.

[0011] The separation functional layer according to the first aspect of the present invention includes a reaction product of a group of compounds comprising compound A having an ether structure a represented by formula (a) and a carbon-carbon unsaturated bond, and compound B having a Si-H group. In the above formula (a), R 1a is a divalent hydrocarbon group. However, if compound A has a plurality of the ether structures a, then a plurality of R 1a They are independent of each other.

[0012] In a second embodiment of the present invention, for example, in the separation functional layer according to the first embodiment, compound A has at least one unsaturated group having a carbon-carbon unsaturated bond at one of its terminals.

[0013] In a third embodiment of the present invention, for example, in the separation functional layer according to the first or second embodiment, the compound A is represented by formula (A1). In the above formula (A1), n ​​is an integer greater than or equal to 1, and R 1a X is a divalent hydrocarbon group, and each of the multiple X groups is an unsaturated group having a carbon-carbon unsaturated bond, provided that n is 2 or more, and there are multiple R groups. 1a They are independent of each other.

[0014] In a fourth embodiment of the present invention, for example, in a separation functional layer according to any one of the first to third embodiments, the divalent hydrocarbon group is an ethane-1,2-diyl group or a propane-1,2-diyl group.

[0015] In a fifth embodiment of the present invention, for example, in a separation functional layer according to any one of the first to fourth embodiments, the compound B includes a structure represented by formula (b). In the above formula (b), R 1b This is a hydrocarbon group which may have a hydrogen atom or a substituent.

[0016] In a sixth aspect of the present invention, for example, in the separation functional layer according to any one of the first to fifth aspects, compound B is a polyorganosiloxane having a Si-H group.

[0017] In a seventh aspect of the present invention, for example, in a separation functional layer according to any one of the first to sixth aspects, the ratio of the number of ether structures a to the number of Si atoms in the reactant is 6.5 or more.

[0018] In the eighth aspect of the present invention, for example, in the separation functional layer according to any one of the first to seventh aspects, the ratio of the number of ether structures a to the number of Si atoms in the reactant is 25.0 or less.

[0019] In the ninth aspect of the present invention, for example, in the separation functional layer according to any one of the first to eighth aspects, the reactants have a crosslinked structure.

[0020] In the tenth embodiment of the present invention, for example, a separation functional layer according to any one of the first to ninth embodiments is used to separate an acidic gas from a mixed gas containing an acidic gas.

[0021] A separation membrane according to the eleventh aspect of the present invention comprises a separation functional layer according to any one of the first to tenth aspects, and a porous support that supports the separation functional layer.

[0022] The details of the present invention will be described below, but the following description is not intended to limit the present invention to any particular embodiment.

[0023] <Embodiment of the Separation Functional Layer> Figure 1 is a cross-sectional view of the separation functional layer 1 of this embodiment. The separation functional layer 1 in Figure 1 can function as a self-supporting membrane (single-layer membrane). The separation functional layer 1 preferably allows acidic gases contained in the mixed gas to permeate preferentially. The separation functional layer 1 is typically a dense layer (non-porous layer) in which no pores can be observed when viewed at a magnification of 5000x using a scanning electron microscope (SEM).

[0024] The separation functional layer 1 contains a reaction product of compound group C, which includes compound A having an ether structure a represented by formula (a) and a carbon-carbon unsaturated bond, and compound B having a hydrosilyl group (Si-H group).

[0025] In the above formula (a), R 1a is a divalent hydrocarbon group. However, when Compound A has a plurality of the above ether structures a, that is, when a plurality of the above ether structures a exist in the molecule of Compound A, the plurality of R 1a are independent of each other.

[0026] Typically, the reactant is a polymer P obtained by an addition reaction (hydrosilylation reaction) of the Si—H group of Compound B to the carbon-carbon unsaturated bond of Compound A. Polymer P has a structural unit derived from Compound A and a structural unit derived from Compound B.

[0027] According to the studies of the present inventors, polymers (particularly polyether block amides) contained in conventional separation functional layers tend to hydrolyze under acidic conditions, and as a result, the separation performance of the separation functional layer tends to decrease. The hydrolyzed polymer (low molecular weight component) may elute from the separation functional layer, causing defects in the separation functional layer or affecting the structure located near the separation functional layer. As an example, in a separation membrane provided with a separation functional layer and a porous support, the pores of the porous support may be blocked by the low molecular weight component eluted from the separation functional layer. In contrast, the above polymer P is difficult to hydrolyze even under acidic conditions and is suitable for suppressing a decrease in separation performance in the separation functional layer.

[0028] Compound A preferably has a plurality of ether structures a. Compound A having a plurality of ether structures is suitable for improving the separation performance of the separation functional layer 1 for acidic gases. In the above formula (a), the plurality of R 1a may be the same as each other or different from each other. The plurality of R 1aThese are independently divalent hydrocarbon groups. The number of carbon atoms in a divalent hydrocarbon group is, for example, 1 to 5, and may be 1 to 3. The divalent hydrocarbon group may be linear or branched. Examples of divalent hydrocarbon groups include alkylene groups such as methylene group, ethane-1,2-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, and propane-2,2-diyl group. 1a Preferably, each R is independently of the other, an ethane-1,2-diyl group or a propane-1,2-diyl group. In compound A, all R 1a However, it may also be a divalent hydrocarbon group (especially a propane-1,2-diyl group or an ethane-1,2-diyl group).

[0029] Compound A has a carbon-carbon unsaturated bond. The carbon-carbon unsaturated bond is, for example, a carbon-carbon double bond or a carbon-carbon triple bond, and preferably a carbon-carbon double bond.

[0030] Compound A contains an unsaturated group having a carbon-carbon unsaturated bond. Compound A preferably has the above unsaturated group at at least one end. Compound A preferably has a molecular structure comprising a main chain having a plurality of ether structures a represented by formula (a) above, and an unsaturated group located at at least one end of the main chain. Compound A is more preferably has unsaturated groups at both ends.

[0031] Examples of unsaturated groups include ethylenically unsaturated groups such as allyl groups, methallyl groups, vinyl groups, acryloyl groups, and methacryloyl groups, as well as hydrocarbon groups having these ethylenically unsaturated groups. The unsaturated group is preferably an allyl group, a methallyl group, or a vinyl group, and more preferably an allyl group or a methallyl group.

[0032] Compound A is preferably represented by the following formula (A1).

[0033] In the above equation (A1), n ​​is an integer greater than or equal to 1, and R 1aX is a divalent hydrocarbon group, and each of the multiple X groups is an unsaturated group having a carbon-carbon unsaturated bond, provided that n is 2 or more, and there are multiple R groups. 1a They are independent of each other.

[0034] In the above formula (A1), it is preferable that n is 2 or greater. 1a They may be the same as each other, or they may be different from each other. 1a Examples of the divalent hydrocarbon group in formula (a) are those described above, and it is preferable that it be an ethane-1,2-diyl group or a propane-1,2-diyl group. In formula (A1), multiple R 1a The ratio N1:N2 of the number of ethane-1,2-diyl groups N1 and the number of propane-1,2-diyl groups N2 in R may be 75:25 to 100:0. 1a It may consist only of ethane-1,2-diyl groups.

[0035] In the above formula (A1), n ​​is 1 or greater as described above, and may be 2 or greater, 10 or greater, 50 or greater, 100 or greater, or even 1000 or greater. The upper limit of n is, for example, 10,000 or less, and may be 5000 or less, 4000 or less, 3000 or less, or even 2000 or less.

[0036] In the above formula (A1), the multiple X values ​​may be the same or different from each other. Examples of the unsaturated group of X include the ethylenically unsaturated groups described above, and are preferably allyl, methallyl, or vinyl groups, and more preferably allyl or methallyl groups.

[0037] In one molecule of compound A, the ratio of the number of oxygen atoms to the total number of oxygen atoms and carbon atoms is, for example, 10% or more, and may be 15% or more, 18% or more, 20% or more, or even 25% or more. The higher this ratio, the more the separation performance of the separation functional layer 1 for acidic gases tends to improve. The upper limit of this ratio is, for example, 50% or less, and may be 40% or less.

[0038] The molecular weight Mw (or number-average molecular weight in some cases) of compound A may be, for example, 90 or more, 100 or more, 200 or more, 500 or more, or 1000 or more. The upper limit of the molecular weight Mw of compound A may be, for example, 100,000 or less, 10,000 or less, 5,000 or less, 3,000 or less, 1,000 or less, 800 or less, and even 500 or less. The molecular weight Mw of compound A may be, for example, 150 to 3000, 200 to 3000, even 200 to 1000, 200 to 800, and even 200 to 500.

[0039] Compound A is preferably a polyalkylene glycol in which at least one end is allyl-modified, methallyl-modified, or vinyl-modified. The polyalkylene glycol preferably has repeating units derived from ethylene glycol and / or propylene glycol. Specific examples of Compound A include the "Sanicol" series manufactured by Sanyo Chemical Industries, Ltd., the Uniox PKA series and Unisafe PKA series manufactured by NOF Corporation, triethylene glycol divinyl ether, diethylene glycol divinyl ether, etc., and may also be the Sanicol DMT series manufactured by Sanyo Chemical Industries, Ltd.

[0040] Compound group C may contain one compound A, or it may contain two or more compounds A.

[0041] Compound B has a hydrosilyl group (Si-H group). The number of Si-H groups in one molecule of compound B may be one or two or more.

[0042] Compound B preferably contains the structure represented by the following formula (b).

[0043] In the above equation (b), R 1bThis is a hydrocarbon group which may have a hydrogen atom or substituents. The number of carbon atoms in the hydrocarbon group is, for example, 1 to 20, and may be 1 to 10, 1 to 5, 1 to 3, or even 1 to 2. Examples of substituents include amino groups, epoxy groups, carboxyl groups, hydroxyl groups, and alkoxy groups. The hydrocarbon group is preferably an alkyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. In some cases, the hydrocarbon group which may have substituents may be a structure derived from a capping agent described later. The number of carbon atoms in the alkoxy group is, for example, 1 to 20, and may be 1 to 12, 1 to 10, 1 to 5, 1 to 3, or even 1 to 2.

[0044] Compound B is typically a polyorganosiloxane having an Si-H group. The Si-H group may be located at the end of the polyorganosiloxane or may be included in the main chain of the polyorganosiloxane. That is, it may be a modified polysiloxane in which at least a portion of the side chains of the polyorganosiloxane are hydrogen. Examples of such polyorganosiloxanes include polymethylhydrogensiloxane, poly(dimethylsiloxane-methylhydrogensiloxane), and hydrosilyl-terminated polydimethylsiloxane.

[0045] Compound B may also be represented by the following formula (B1).

[0046] In the above formula (B1), multiple R 1b These are hydrocarbon groups that may have hydrogen atoms or substituents, and a plurality of R 2b R is a hydrogen atom, a hydrocarbon group which may have substituents, or any substituent, and m is an integer of 1 or more. 1b At least one of them is a hydrogen atom. If m is 2 or more, there are multiple R 1b They are independent of each other.

[0047] In the above formula (B1), multiple R 1b R may be the same as the others, or it may be different from the others. In the above formula (B1), 1b This is the same as equation (b).

[0048] As mentioned above, R 1b The hydrocarbon group, which may have substituents, may have a structure derived from the capping agent. Compound B may have a structure in which some of the Si-H groups in the compound having Si-H groups are capped by the capping agent. With such a configuration, side reactions, which are reactions between the Si-H groups and substances other than compound A (such as solvents), can be suppressed. By suppressing such side reactions, the change in the gas separation performance of the separation functional layer 1 over time can be suppressed. Here, "the Si-H groups are capped" means that the Si-H groups are inactivated by the capping agent.

[0049] The capping agent is a compound that can deactivate Si-H groups. Preferably, the capping agent has only one functional group that is reactive with Si-H groups and does not have any other structures that are reactive with Si-H groups or carbon-carbon unsaturated bonds. With such a configuration, the durability of the separation membrane, in particular the retention rate of the permeability coefficient, can be improved. The functional group that is reactive with Si-H groups has a carbon-carbon unsaturated bond. The carbon-carbon unsaturated bond is, for example, a carbon-carbon double bond or a carbon-carbon triple bond, and preferably a carbon-carbon double bond.

[0050] In the above formula (B1), multiple R 2b These may be the same or different from each other. The number of carbon atoms in the hydrocarbon group may be, for example, 1 to 5, 1 to 3, or even 1 to 2. Examples of substituents on the hydrocarbon group are those described above for formula (b). An arbitrary substituent is, for example, a hydroxyl group. R 2b The group is preferably an alkyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0051] R in compound B 1b The ratio of the number of hydrogen atoms to the number of ions may be between 1% and 90%, or between 5% and 85%, 10% and 80%, or even between 20% and 70%.

[0052] In the above formula (B1), m is 1 or greater as described above, and may be 2 or greater, or even 10 or greater. The upper limit of m is, for example, 10,000 or less, and may be 1,000 or less, or even 100 or less.

[0053] Compound B may also be represented by the following formula (B2).

[0054] In the above formula (B2), multiple R 3b These are hydrocarbon groups that may have substituents, and a plurality of R 2b These are, independently of each other, a hydrogen atom, a hydrocarbon group which may have substituents, or any substituent, where m1 is an integer of 1 or more and m2 is an integer of 0 or more.

[0055] In the above formula (B2), R 3b Examples of substituents and hydrocarbon groups are shown in formula (b) R 1b This is the same as the explanation given above. In the above formula (B2), multiple R 3b They may be the same as each other, or they may be different from each other.

[0056] In the above formula (B2), R 2b This is the same as formula (B1). Multiple R 2b They may be the same as each other, or they may be different from each other.

[0057] m1 is 1 or greater, and may be 2 or greater, or even 20 or greater. The upper limit of m1 is, for example, 10,000 or less, and may be 1,000 or less, or even 100 or less. m2 is 0 or greater, and may be 1,000 or less, 100 or less, 50 or less, or even 25 or less. m2 may also be 0.

[0058] The ratio of m1:m2 can be between 20:24 and 50:0.

[0059] The molecular weight Mw (or number-average molecular weight in some cases) of compound B is, for example, 100 or more, and may be 1000 or more, or even 2000 or more. The upper limit of the molecular weight Mw of compound B is, for example, 1 million or less, and may be 10,000 or less, 5000 or less, or even 3000 or less.

[0060] Compound group C may contain one compound B, or it may contain two or more compounds B.

[0061] Compound group C may or may not contain compounds other than those described above, such as compounds A and B. Preferably, compound group C consists substantially only of compounds A and B. Preferably, compound group C does not contain a crosslinking agent as a compound other than those described above, such as compounds A and B.

[0062] In compound group C, the ratio of the total mass of compound A to the sum of the masses of all compound A and all compound B may be, for example, 50% or more, 70% or more, or even 85% or more. The upper limit of the ratio of the total mass of compound A to the sum of the masses of all compound A and all compound B may be, for example, 99% or less, 95% or less, or even 90% or less.

[0063] As described above, polymer P is obtained by the addition reaction (hydrosilylation reaction) of the Si-H group of compound B to the carbon-carbon unsaturated bond of compound A. The above reaction is typically carried out in the presence of a curing catalyst (hydrosilylation catalyst). Therefore, the separation functional layer 1 according to this embodiment preferably contains polymer P, which is a reaction product obtained by reacting compound group C, which includes compound A and compound B, in the presence of a curing catalyst.

[0064] Examples of curing catalysts include platinum-based catalysts. Specific examples of platinum-based catalysts include chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes.

[0065] From the viewpoint of improving the mechanical strength of the separation functional layer 1, it is preferable that the polymer P has a crosslinked structure.

[0066] Polymer P preferably has a structure represented by the following formula (a1) as a structure derived from compound A. The structural unit represented by formula (a1) is derived from compound A represented by the above formula (A1).

[0067] In equation (a1), R 1a And n are the same as in equation (A1). R2a This is a divalent linking group. 1 R is a bond position with other atoms in polymer P, and is typically a bond position with Si atoms in a configuration derived from compound B. 2a This originates from the unsaturated group of compound A. The divalent linking group is preferably a hydrocarbon group, and more preferably an ethane-1,2-diyl group or a propane-1,2-diyl group.

[0068] Polymer P preferably has a structure represented by the following formula (b1) as a structure derived from compound B. The structural unit represented by formula (b1) is derived from compound B represented by the above formula (B1).

[0069] In equation (b1), * 2 This is the bonding position with other atoms in polymer P, and is typically the bonding position with carbon atoms in the configuration derived from compound A. Bonding position* 2 This originates from the Si-H group contained in compound B. Multiple R 3b These are, independently of each other, a hydrogen atom, a hydrocarbon group which may have substituents, or a bond position* 2 Therefore, multiple R 4b m1 is a hydrogen atom, a hydrocarbon group which may have substituents, or any substituent, independently of each other, and m2 is an integer of 0 or more.

[0070] In the above equation (b1), multiple R 3b They may be the same as each other, or they may be different from each other. 3b Preferably, a hydrocarbon group which may have substituents, or a bond position * 2 The hydrocarbon group has, for example, 1 to 20 carbon atoms, and may also be 1 to 10, 1 to 5, 1 to 3, or even 1 to 2 carbon atoms. Substituents in the hydrocarbon group include those described above for formula (b). An arbitrary substituent is, for example, a hydroxyl group. R 3b The group is preferably an alkyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0071] In the above equation (b1), multiple R 4b They may be the same as each other, or they may be different from each other. 4b Preferably, is a hydrocarbon group which may have substituents, or any substituent. The number of carbon atoms in the hydrocarbon group is, for example, 1 to 5, and may be 1 to 3, or even 1 to 2. Examples of substituents in the hydrocarbon group are those described above for formula (b). An example of an arbitrary substituent is a hydroxyl group. R 4b The group is preferably an alkyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0072] In the above formula (b1), m1 is 0 or greater as described above, and may be 1 or greater, 2 or greater, 5 or greater, or even 10 or greater. The upper limit of m1 is, for example, 10,000 or less, and may be 5,000 or less, 1,000 or less, 500 or less, 100 or less, or even 50 or less. As described above, m2 is 0 or greater, and may be 1 or greater, 2 or greater, 5 or greater, or even 10 or greater. The upper limit of m2 is, for example, 10,000 or less, and may be 5,000 or less, 1,000 or less, 500 or less, 100 or less, or even 50 or less.

[0073] Therefore, it is preferable that polymer P contains a structure represented by the following formula (C1).

[0074] In equation (C1), R 1a , and n are the same as in equation (A1). R 2a This is the same as equation (a1). R 3b , R 4b m1 and m2 are the same as in formula (b1), and multiple R 3b Each is independent, and multiple R 4b These are independent of each other. m3 is a non-negative integer, and m4 is a non-negative integer.

[0075] In formula (C1), the numerical ranges of m1 and m2 are as described above for formula (b1). As described above, m3 is 0 or greater, and may be 1 or greater, 2 or greater, 5 or greater, or even 10 or greater. The upper limit of m3 is, for example, 10,000 or less, and may be 5,000 or less, 1,000 or less, 500 or less, 100 or less, or even 50 or less. As described above, m4 is 0 or greater, and may be 1 or greater, 2 or greater, 5 or greater, or even 10 or greater. The upper limit of m4 is, for example, 10,000 or less, and may be 5,000 or less, 1,000 or less, 500 or less, 100 or less, or even 50 or less.

[0076] The ratio of the number of ether structures a represented by formula (a) above to the number of Si atoms in polymer P may be 0.5 or more and 50.0 or less, 1.0 or more and 45.0 or less, 2.0 or more and 40.0 or less, 5.0 or more and 30.0 or less, 6.5 or more and 25.0 or less, 7.0 or more and 20.0 or less, or 10.0 or more and 15.0 or less. Alternatively, the ratio of the number of ether structures a represented by formula (a) above to the number of Si atoms in polymer P may be 25.0 or less, greater than 0 and 15.0 or less, 0.1 or more and 10.0 or less, 0.5 or more and 6.5 or less, or 0.5 or more and less than 6.5. The above ratio can be measured, for example, by solid-state nuclear magnetic resonance (solid-state NMR). The above ratio can also be calculated from the composition and ratio of compounds A and B used as raw materials.

[0077] In another aspect, the present invention provides a separation functional layer comprising a reaction product of a group of compounds including compound A having an ether structure a represented by formula (a) and compound B having a Si-H group, wherein the ratio of the number of ether structures a represented by formula (a) to the number of Si atoms in the reaction product is 6.5 or more.

[0078] In another aspect, the present invention provides a separation functional layer comprising a reactant of a group of compounds including compound A having an ether structure a represented by formula (a) and compound B having a Si-H group, wherein the ratio of the number of ether structures a represented by formula (a) to the number of Si atoms in the reactant is 25.0 or less.

[0079] In the above equation (a), R 1a is a divalent hydrocarbon group. However, if compound A has multiple ether structures a, then multiple R 1a They are independent of each other.

[0080] The reactant described above is typically polymer P.

[0081] The glass transition temperature (Tg) of polymer P is not particularly limited and may be, for example, 0°C or lower, and may be between -70°C and -40°C, or around -55°C. In this specification, the glass transition temperature Tg is defined as the intermediate glass transition temperature (T) determined in accordance with the provisions of JIS K7121:1987. mg ) means.

[0082] The gel fraction of polymer P is preferably, for example, 50% or more, and more preferably 60% or more, 70% or more, 80% or more, and even more preferably 90% or more. The upper limit of the gel fraction of polymer P is not particularly limited and may be, for example, 99% or less, and also 95% or less. The gel fraction of the separation functional layer 1 is preferably 50% to 99%, 60% to 99%, 70% to 99%, and more preferably 90% to 99% or more.

[0083] The polymer P content in the separation functional layer 1 is, for example, 50 wt% or more, and may be 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, or even 95 wt% or more. The separation functional layer 1 may be composed substantially of polymer P alone.

[0084] The separation functional layer 1 may further contain other components besides polymer P. Examples of other components include other polymers, oligomers, fillers, etc.

[0085] It is preferable that the separation functional layer 1 does not contain polymer P, which is a reaction product of compound A and compound B, that has been further crosslinked with a crosslinking agent such as an isocyanate crosslinking agent. In this specification, polymer P does not contain polymer P in which the reaction products of compound A and compound B have been further crosslinked with the above-mentioned crosslinking agent.

[0086] The thickness of the separation functional layer 1 is, for example, 500 μm or less, and may be 300 μm or less, 100 μm or less, 50 μm or less, 25 μm or less, 15 μm or less, 10 μm or less, 5.0 μm or less, 2.0 μm or less, 1.0 μm or less, 0.5 μm or less, and even 0.2 μm or less. The thickness of the separation functional layer 1 may be 0.05 μm or more, or 0.1 μm or more.

[0087] (Method for manufacturing the separation functional layer) In this embodiment, the method for manufacturing the separation functional layer 1 preferably includes the steps of applying a coating solution having a group of compounds C including compound A and compound B onto a substrate to form a coating film, and drying the coating film to form a polymer P from the group of compounds C.

[0088] The compounds A and B included in compound group C are those described above.

[0089] The content of the compound group (compound A and compound B) in the coating solution is, for example, 0.1 wt% to 30 wt%. The ratio of the mass of compound A to the total mass of compound A and compound B in the coating solution is, for example, 50% or more, and may be 70% or more, or even 85% or more. The upper limit of the above ratio is, for example, 99% or less, and may be 95% or less, or even 90% or less.

[0090] The coating solution preferably further contains a curing catalyst. Examples of curing catalysts include those mentioned above.

[0091] The coating solution preferably further contains a solvent. The solvent is preferably capable of dissolving compound A and compound B. Examples of solvents include toluene, ethyl acetate, diisopropyl ether, isopropanol (IPA) and other alcohol compounds, as well as mixed solvents of two or more of these. The solvent content in the coating solution is not particularly limited and may be, for example, 30 wt% to 99.9 wt%, 50 wt% to 99 wt%, or even 70 wt% to 98 wt%.

[0092] In the manufacturing method of this embodiment, as described above, a coating liquid is applied to a substrate to form a coating film. The substrate to which the coating liquid is applied is typically a release liner. Examples of substrates include films containing resin; paper; and sheets containing metal materials such as aluminum and stainless steel. Sheets containing metal materials tend to have high heat resistance. The substrate is preferably a film containing resin because it has excellent surface smoothness. Examples of polymers contained in the resin of the substrate include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, and polymethylpentene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyvinyl chloride, vinyl chloride copolymer; polyurethane; ethylene-vinyl acetate copolymer; and polyimide.

[0093] The surface of the substrate may be treated with a release agent. The release agent can be applied to the surface of the substrate by applying a release agent. Examples of release agents include silicone-based release agents, long-chain alkyl-based release agents, fluorine-based release agents, and molybdenum sulfide-based release agents. The release agents may be used individually or in combination of two or more types.

[0094] The thickness of the substrate is not particularly limited, and is, for example, 5 μm to 100 μm, preferably 10 μm to 50 μm.

[0095] Furthermore, a surface modification treatment may be performed on the substrate before applying the coating solution. If the substrate has been subjected to a stripping treatment, the surface modification treatment may be performed on the surface of the substrate that has been stripped. Examples of surface modification treatments include corona treatment, plasma treatment, excimer treatment, and flame treatment, with corona treatment being preferred.

[0096] Surface modification can be performed by irradiating the surface of the substrate with active energy rays. Specific examples of active energy rays include electron beams, ion beams, plasma beams, and ultraviolet rays. When corona treatment is used as a surface modification treatment, the discharge rate is, for example, 0.1 kW·min / m 2 That concludes the explanation. The upper limit of the discharge rate is not particularly limited; for example, 10 kW·min / m 2 That is the case.

[0097] The method of applying the coating solution to the substrate is not particularly limited, and for example, spin coating, dip coating, slot die coating, gravure coating, comma coating, spray coating, etc., can be used. The coating solution may also be applied to the substrate using an applicator, wire bar, non-wire bar, etc. The coating solution may be applied to the surface of a substrate that has undergone stripping treatment or surface modification treatment.

[0098] A coating film is formed by applying the coating solution to the substrate. The thickness of the coating film can be appropriately adjusted according to the desired thickness of the separation functional layer 1, for example, from 1 μm to 100 μm.

[0099] In the manufacturing method of this embodiment, as described above, the coated film is dried to form polymer P from compound group C. This yields the separation functional layer 1.

[0100] The drying conditions for the coating film are not particularly limited, as long as polymer P can be formed from the compound group. The drying temperature of the coating film may be, for example, 50°C or higher, and may be 70°C or higher. The upper limit of the drying temperature may be, for example, 180°C or lower, and may be 150°C or lower. The drying time of the coating film may be, for example, 10 seconds or more, and may be 30 seconds or more. The upper limit of the drying time may be, for example, 1 hour or less, 30 minutes or less, and even 10 minutes or less. In this embodiment, the formation of polymer P from the compound group tends to proceed relatively quickly. Therefore, the coating film tends to harden relatively quickly, and as a result, the separation functional layer 1 is easily formed uniformly.

[0101] The coating film can be dried using a heater or the like. For example, the coating film may be dried by passing it through a heating section equipped with a heater. The coating film may also be dried by passing it through multiple heating sections. The set temperatures of the multiple heating sections may be the same or different. In this embodiment, the separation functional layer 1 can also be formed using a roll-to-roll method.

[0102] The manufacturing method of this embodiment preferably further includes removing the substrate from the laminate of the separation functional layer 1 and the substrate. By removing the substrate, a separation functional layer 1 that functions as a self-supporting membrane can be obtained.

[0103] (Applications of the Separation Functional Layer) One application of the separation functional layer 1 of this embodiment is to separate acidic gases from a gas mixture containing acidic gases. Examples of acidic gases in the gas mixture include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, nitrogen oxides (NOx), and preferably carbon dioxide. The gas mixture contains other gases besides the acidic gas. Examples of other gases include nonpolar gases such as hydrogen, nitrogen, and methane, and inert gases such as helium, and preferably nitrogen. In particular, the separation functional layer 1 of this embodiment is suitable for separating carbon dioxide from a gas mixture containing carbon dioxide and nitrogen. However, the applications of the separation functional layer 1 are not limited to separating acidic gases from the gas mixture described above.

[0104] <Embodiment of the Separation Membrane> As shown in Figure 2, the separation membrane 10 of this embodiment preferably comprises the separation functional layer 1 described above and further comprises a porous support 3 that supports the separation functional layer 1. The separation membrane 10 may further comprise an intermediate layer 2 disposed between the separation functional layer 1 and the porous support 3, and in direct contact with the separation functional layer 1 and the porous support 3, respectively.

[0105] (Intermediate layer) Intermediate layer 2 preferably contains a resin. Examples of resins include silicone resins such as polydimethylsiloxane; fluororesins such as polytetrafluoroethylene; epoxy resins such as polyethylene oxide; polyimide resins; polysulfone resins; polyacetylene resins such as polytrimethylsilylpropine and polydiphenylacetylene; polyolefin resins such as polymethylpentene; and polyurethane resins. Intermediate layer 2 preferably contains a silicone resin.

[0106] The intermediate layer 2 may further contain fillers dispersed in the resin (matrix). The fillers may be spaced apart from each other within the matrix, or they may be partially aggregated. However, the intermediate layer 2 may not contain fillers and may be substantially composed of resin.

[0107] The filler may contain inorganic materials or organic materials. Examples of inorganic materials included in the filler include silica, titania, and alumina. It is preferable that the filler contains silica.

[0108] The average particle size of the filler is not particularly limited, but is, for example, 100 nm or less, preferably 50 nm or less, and more preferably 20 nm or less. The lower limit of the average particle size of the filler is, for example, 1 nm. The average particle size of the filler can be determined by the following method. First, the cross-section of the intermediate layer 2 is observed with a transmission electron microscope. In the obtained electron microscope image, the area of ​​a specific filler is calculated by image processing. The diameter of a circle having the same area as the calculated area is considered to be the particle size (diameter of the particle) of that specific filler. The particle size of any number of fillers (at least 50) is calculated, and the average of the calculated values ​​is considered to be the average particle size of the filler. The shape of the filler is not particularly limited, and may be spherical, ellipsoidal, flaky, or fibrous.

[0109] The filler content in the intermediate layer 2 is, for example, 5 wt% or more, preferably 10 wt% or more, and more preferably 15 wt% or more. The upper limit of the filler content in the intermediate layer 2 is not particularly limited, but is, for example, 30 wt%.

[0110] The thickness of the intermediate layer 2 is not particularly limited and may be, for example, 50 μm or less, but may also be 30 μm or less, 10 μm or less, 1 μm or less, or even 0.5 μm or less. The lower limit of the thickness of the intermediate layer 2 is not particularly limited and may be, for example, 0.01 μm or more, but may also be 0.1 μm or more.

[0111] The intermediate layer 2 may be formed from an emulsion resin composition. The emulsion resin composition means a liquid containing a dispersion medium and a polymer emulsified in the dispersion medium. The emulsion resin composition preferably contains water as the dispersion medium. That is, the emulsion resin composition is preferably an oil-in-water (O / W) emulsion. The emulsion resin composition may contain an organic solvent as the dispersion medium, either in place of water or together with water.

[0112] (Porous Support) The porous support 3 supports the separation functional layer 1 via the intermediate layer 2. Examples of the porous support 3 include nonwoven fabric; porous polytetrafluoroethylene; aromatic polyamide fiber; porous metal; sintered metal; porous ceramic; porous polyester; porous nylon; activated carbon fiber; latex; silicone; silicone rubber; permeable (porous) polymer containing at least one selected from the group consisting of polyvinyl fluoride, polyvinylidene fluoride, polyurethane, polypropylene, polyethylene, polystyrene, polycarbonate, polysulfone, polyetheretherketone, polyacrylonitrile, polyimide, and polyphenylene oxide; metal foam having open or closed cells; polymer foam having open or closed cells; silica; porous glass; mesh screen, etc. The porous support 3 may be a combination of two or more of these. As an example, the porous support 3 may be a laminate of a nonwoven fabric and a polysulfone porous layer.

[0113] The porous support 3 has an average pore diameter of, for example, 0.01 μm to 0.4 μm. The thickness of the porous support 3 is not particularly limited, but is, for example, 10 μm or more, preferably 20 μm or more, and more preferably 50 μm or more. The thickness of the porous support 3 is, for example, 300 μm or less, preferably 200 μm or less, and more preferably 150 μm or less.

[0114] (Protective layer) The separation membrane 10 may further include a protective layer (not shown) for protecting the separation functional layer 1. The protective layer is preferably in direct contact with the separation functional layer 1. The separation functional layer 1 is typically located between the protective layer and the intermediate layer 2.

[0115] The protective layer preferably contains a resin. Examples of resins include those described above for the intermediate layer 2. The protective layer preferably contains a silicone resin.

[0116] The thickness of the protective layer is not particularly limited, and is, for example, 0.01 μm to 50 μm.

[0117] (Method for manufacturing a separation membrane) The separation membrane 10 can be manufactured by the following method. First, a laminate of a porous support 3 and an intermediate layer 2 is prepared. This laminate can be manufactured by the following method. First, a coating solution containing the material for the intermediate layer 2 is prepared. Next, the coating solution containing the material for the intermediate layer 2 is applied to the porous support 3 to form a coating film. The method of applying the coating solution is not particularly limited, and for example, spin coating, dip coating, slot die coating, gravure coating, comma coating, spray coating, etc., can be used. The coating solution may also be applied to the substrate using an applicator, wire bar, non-wire bar, etc. Next, the coating film is dried to form the intermediate layer 2. Drying of the coating film can be carried out under heating conditions. The heating temperature of the coating film is, for example, 50°C or higher. The heating time of the coating film is, for example, 1 minute or more, and may be 5 minutes or more. Furthermore, the surface of the intermediate layer 2 may be treated with an easy-adhesion treatment as needed. Examples of easy-adhesion treatments include surface treatments such as application of a primer, corona discharge treatment, and plasma treatment.

[0118] Next, a separation functional layer 1 is formed on the intermediate layer 2 in the laminate of the porous support 3 and the intermediate layer 2. This allows a separation membrane 10 to be obtained. As an example, the separation membrane 10 can be produced by using the laminate of the porous support 3 and the intermediate layer 2 as a substrate and carrying out the above-described manufacturing method for the separation functional layer 1.

[0119] The method for producing the separation membrane 10 is not limited to the method described above, and the separation membrane 10 may also be produced by the following method. First, a separation functional layer 1 is prepared on a substrate such as a peelable liner by the method described above. Next, an intermediate layer 2 is formed by coating a coating solution containing the material for the intermediate layer 2 onto the separation functional layer 1 and drying it. The laminate of the intermediate layer 2 and the separation functional layer 1 is transferred to a porous support 3. This gives rise to the separation membrane 10.

[0120] (Shape of the separation membrane) In this embodiment, the separation membrane 10 is typically a flat membrane. However, the separation membrane 10 may have a shape other than a flat membrane, and may be a hollow fiber membrane. For example, the separation membrane 10 as a hollow fiber membrane may have a separation functional layer 1 and a porous support 3, but may not have an intermediate layer 2.

[0121] (Characteristics of the separation membrane) The separation membrane 10 of this embodiment can, for example, preferentially permeate acidic gases contained in a gas mixture. As an example, when carbon dioxide at a pressure of 0.1 MPa is supplied to a space adjacent to one side of the separation membrane 10, the permeation rate T1 of carbon dioxide that permeates through the separation membrane 10 is CO2 For example, this could be 100 GPU or more, 300 GPU or more, 400 GPU or more, 500 GPU or more, 750 GPU or more, and even 900 GPU or more. Transmission velocity T1 CO2 The upper limit is not particularly limited; for example, it may be 5000 GPU or less, or 2000 GPU or less. Note that the GPU is 10 -6 ・cm 3 (STP) / (sec・cm 2 This means cmHg. 3 (STP) refers to the volume of a gas at 1 atmosphere and 0°C.

[0122] Transmission rate T1 CO2 This can be calculated by the following method. First, carbon dioxide at a pressure of 0.1 MPa and a temperature of 25°C is supplied to the space adjacent to one side of the separation membrane 10 (for example, the main surface 11 on the separation functional layer side of the separation membrane 10). As a result, permeate fluid (carbon dioxide) that has permeated through the separation membrane 10 is obtained from the other main surface of the separation membrane 10 (for example, the main surface 12 on the porous support side of the separation membrane 10). The flow rate of this permeate fluid is measured with a mass flow meter, and from the obtained result, the permeation rate of carbon dioxide T1 CO2 Measure the (GPU). Depending on the flow rate of the permeate fluid, a soap film flow meter may be used instead of a mass flow meter.

[0123] The separation coefficient α1 of carbon dioxide relative to nitrogen in the separation membrane 10 is not particularly limited, and may be, for example, 15 or more, 16 or more, 18 or more, 20 or more, or even 30 or more. The upper limit of the separation coefficient α1 is not particularly limited, and may be, for example, 100 or less, or 50 or less.

[0124] The separation coefficient α1 is the nitrogen permeation rate T1 that passes through the separation membrane 10 when nitrogen at a pressure of 0.1 MPa is supplied to the space adjacent to one side of the separation membrane 10. N2 The permeation rate T1 of carbon dioxide that permeates through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space (GPU). CO2 (GPU) ratio T1 CO2 / T1 N2 This means the nitrogen permeation rate T1 N2 Except for using nitrogen at a pressure of 0.1 MPa and a temperature of 25°C instead of carbon dioxide, the permeation rate of carbon dioxide T1 CO2 This can be measured by the method described above.

[0125] The separation functional layer 1 of the separation membrane 10 in this embodiment has high acid resistance, and the deterioration of separation performance under acidic conditions tends to be suppressed. As an example, the ratio of the separation coefficient α2 of carbon dioxide to nitrogen of the separation membrane 10 after durability test I to the separation coefficient α1 of carbon dioxide to nitrogen of the separation membrane 10 before durability test I is, for example, 50% or more, and may be 60% or more, 70% or more, 80% or more, or even 90% or more. The upper limit of this ratio may be, for example, 120% or less, and may be 100% or less. Durability test I: A test gas, which is a mixture of a gas composed of nitrogen and nitrogen oxides (NOx) and water vapor, is brought into contact with the separation membrane 10 for 7 days. Here, the nitrogen oxide content in the gas mixture is 500 vol ppm, the test gas is at a temperature of 25°C, and the humidity is 60% RH.

[0126] The permeation rate T1 of carbon dioxide that passes through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space adjacent to one side of the separation membrane 10 before performing the above durability test I. CO2The permeation rate T2 of carbon dioxide that permeates through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space adjacent to one side of the separation membrane 10 after durability test I against GPU. CO2 The GPU ratio may be, for example, 150% or less, 130% or less, or even 100% or less. The lower limit of this ratio may be, for example, 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more.

[0127] The above durability test I can be carried out by the following method. First, the separation membrane 10 is placed inside the gas bag. The gas bag is preferably one that can permeate water vapor but hardly permeates nitrogen or nitrogen oxides. For example, the Smart Bag PA (model AAK-5) manufactured by GL Sciences can be used. Next, a mixed gas composed of nitrogen and nitrogen oxides (temperature: 25°C, pressure: 101.325 kPa, nitrogen oxide content: 500 vol ppm) is sealed inside the gas bag, and after performing the removal operation once, the mixed gas is sealed inside the gas bag again and the gas bag is sealed.

[0128] Next, the gas bag is placed in an environment with a temperature of 25°C and a humidity of 60% RH. This allows water vapor to permeate the gas bag, and the water vapor mixes with the aforementioned gas mixture inside the bag, forming a test gas (temperature: 25°C, humidity: 60% RH). Durability test I can be performed by leaving the gas bag in this state for 7 days.

[0129] The separation coefficient α2 of carbon dioxide relative to nitrogen of the separation membrane 10 after durability test I is, for example, 15 or more, and may be 17 or more, 18 or more, 20 or more, or even 30 or more. The upper limit of the separation coefficient α2 is not particularly limited and may be, for example, 100 or less, and may be 50 or less.

[0130] The separation coefficient α2 is the nitrogen permeation rate T2 when nitrogen at a pressure of 0.1 MPa is supplied to the space adjacent to one side of the separation membrane 10 after durability test I has been performed. N2The permeation rate T2 of carbon dioxide that permeates through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space with respect to the (GPU). CO2 The ratio T2 of (GPU). CO2 / T2 N2 means. The permeation rate T2 CO2 and T2 N2 are, respectively, except for using the separation membrane 10 after the durability test I, the permeation rates T1 CO2 and T1 N2 can be measured by the method described above.

[0131] The permeation rate T2 CO2 is, for example, 100 GPU or more, 300 GPU or more, 500 GPU or more, 750 GPU or more, and even 800 GPU or more. The permeation rate T2 CO2 The upper limit of is, for example, 5000 GPU or less, 2000 GPU or less, 1000 GPU or less, and even 900 GPU or less.

[0132] The separation functional layer 1 included in the separation membrane 10 of this embodiment sometimes has high durability against water, and there is a tendency to suppress a decrease in separation performance due to cleaning operations such as immersion in water. As an example, the ratio of the carbon dioxide separation coefficient α3 of the separation membrane 10 with respect to nitrogen after performing the following durability test II to the carbon dioxide separation coefficient α1 of the separation membrane 10 with respect to nitrogen before performing the durability test II (initial state) is, for example, 70% or more, 75% or more, 80% or more, 90% or more, and even 98% or more. The upper limit of this ratio is, for example, 150% or less, and even 130% or less. Durability test II: The separation membrane 10 is stored for 1 day in a state of being immersed in water at room temperature. Then, the separation membrane 10 is taken out of the water, and the separation membrane 10 is dried in a dryer at 70°C for 2 hours.

[0133] The permeation rate T1 of carbon dioxide that permeates through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space adjacent to one surface of the separation membrane 10 before performing the above durability test II CO2The permeation rate T3 of carbon dioxide that permeates through the separation membrane 10 when carbon dioxide at a pressure of 0.1 MPa is supplied to the space adjacent to one surface of the separation membrane 10 after the durability test II is performed on the (GPU). CO2 The ratio of (GPU) is, for example, 150% or less, and may be 135% or less, and further may be 120% or less. The lower limit of this ratio may be, for example, 50% or more, 60% or more, 70% or more, 80% or more, and further may be 90% or more.

[0134] The separation factor α3 of carbon dioxide with respect to nitrogen of the separation membrane 10 after the durability test II is, for example, 20 or more, and may be 25 or more, 27 or more, 30 or more, and further may be 35 or more. The upper limit of the separation factor α3 is not particularly limited and may be, for example, 100 or less, or 50 or less.

[0135] The separation factor α3 is the permeation rate T3 of nitrogen that permeates through the separation membrane 10 when nitrogen at a pressure of 0.1 MPa is supplied to the space adjacent to one surface of the separation membrane 10 after the durability test II is performed. N2 The permeation rate T3 of carbon dioxide after the durability test II with respect to the (GPU). CO2 The ratio T3 of the (GPU). CO2 / T3 N2 means. The permeation rate T3 CO2 and T3 N2 are each, except for using the separation membrane 10 after the durability test II, the permeation rates T1 CO2 and T1 N2 can be measured by the method described above. [[ID= , except for using the separation membrane 1 after the durability test II, the permeation rates T1 and T1 can be measured by the method described above.]]

[0136] The permeation rate T3 CO2 is, for example, 100 GPU or more, 300 GPU or more, 400 GPU or more, 500 GPU or more, 750 GPU or more, and further 800 GPU or more. The upper limit of the permeation rate T3 CO2 is, for example, 5000 GPU or less, 2000 GPU or less, 1500 GPU or less, and further may be 1300 GPU or less.

[0137] <Embodiment of Membrane Separation Apparatus> As shown in Figure 3, the membrane separation apparatus 100 of this embodiment comprises a separation membrane 10 and a tank 20. In the membrane separation apparatus 100, it is also possible to use a separation functional layer 1 by itself instead of the separation membrane 10. The tank 20 comprises a first chamber 21 and a second chamber 22. The separation membrane 10 is located inside the tank 20. Inside the tank 20, the separation membrane 10 separates the first chamber 21 and the second chamber 22. The separation membrane 10 extends from one of a pair of walls of the tank 20 to the other.

[0138] The first chamber 21 has an inlet 21a and an outlet 21b. The second chamber 22 has an outlet 22a. Each of the inlet 21a, outlet 21b, and outlet 22a is, for example, an opening formed in the wall surface of the tank 20.

[0139] Membrane separation using the membrane separation apparatus 100 is performed, for example, by the following method. First, a mixed gas 30 containing an acidic gas is supplied to the first chamber 21 through the inlet 21a. The concentration of the acidic gas in the mixed gas 30 is not particularly limited, and under standard conditions, it is, for example, 0.01 vol% (100 ppm) or more, preferably 1 vol% or more, more preferably 10 vol% or more, even more preferably 30 vol% or more, and particularly preferably 50 vol% or more. The upper limit of the concentration of the acidic gas in the mixed gas 30 is not particularly limited, and under standard conditions, it is, for example, 90 vol%.

[0140] The pressure inside the first chamber 21 may be increased by supplying the mixed gas 30. The membrane separation device 100 may further include a pump (not shown) for increasing the pressure of the mixed gas 30. The pressure of the mixed gas 30 supplied to the first chamber 21 is, for example, 0.1 MPa or more, preferably 0.3 MPa or more.

[0141] The second chamber 22 may be depressurized while the mixed gas 30 is supplied to the first chamber 21. The membrane separation device 100 may further include a pump (not shown) for depressurizing the second chamber 22. The second chamber 22 may be depressurized such that the space inside the second chamber 22 is, for example, 10 kPa or more, preferably 50 kPa or more, and more preferably 100 kPa or more, than the atmospheric pressure in the measurement environment.

[0142] By supplying the mixed gas 30 into the first chamber 21, a permeate fluid 35 with a higher acidic gas content than the mixed gas 30 can be obtained on the other side of the separation membrane 10. That is, the permeate fluid 35 is supplied to the second chamber 22. The permeate fluid 35 mainly contains, for example, an acidic gas. However, the permeate fluid 35 may also contain small amounts of other gases besides acidic gases. The permeate fluid 35 is discharged to the outside of the tank 20 through the outlet 22a.

[0143] The concentration of acidic gas in the gas mixture 30 gradually decreases from the inlet 21a to the outlet 21b of the first chamber 21. The gas mixture 30 (impermeable fluid 36) treated in the first chamber 21 is discharged to the outside of the tank 20 through the outlet 21b.

[0144] The membrane separation apparatus 100 of this embodiment is suitable for a continuous flow membrane separation method. However, the membrane separation apparatus 100 of this embodiment may also be used for a batch membrane separation method.

[0145] <Modifications of the Membrane Separation Apparatus> The membrane separation apparatus 100 may be a spiral-type membrane element, a hollow fiber membrane element, etc. Figure 4 shows a spiral-type membrane element. The membrane separation apparatus 110 in Figure 4 comprises a central tube 41 and a laminate 42. The laminate 42 contains the separation membrane 10. The laminate 42 may contain a separation functional layer 1 by itself instead of the separation membrane 10.

[0146] The central tube 41 has a cylindrical shape. Multiple holes are formed on the surface of the central tube 41 to allow the permeable fluid 35 to flow into the interior of the central tube 41. Examples of materials for the central tube 41 include resins such as acrylonitrile butadiene styrene copolymer resin (ABS resin), polyphenylene ether resin (PPE resin), and polysulfone resin (PSF resin); and metals such as stainless steel and titanium. The inner diameter of the central tube 41 is, for example, in the range of 20 to 100 mm.

[0147] The laminate 42 further includes a supply-side channel material 43 and a permeate-side channel material 44 in addition to the separation membrane 10. The laminate 42 is wound around the central tube 41. The membrane separation device 110 may further include an outer casing material (not shown).

[0148] For the supply-side channel material 43 and the permeate-side channel material 44, for example, a resin net made of polyphenylene sulfide (PPS) or ethylene-chlorotrifluoroethylene copolymer (ECTFE) can be used.

[0149] Membrane separation using the membrane separation device 110 is performed, for example, by the following method. First, a mixed gas 30 is supplied to one end of the wound laminate 42. The permeate fluid 35 that has permeated through the separation membrane 10 of the laminate 42 moves into the center tube 41. The permeate fluid 35 is discharged to the outside through the center tube 41. The mixed gas 30 (impermeable fluid 36) processed by the membrane separation device 110 is discharged to the outside from the other end of the wound laminate 42. This makes it possible to separate acidic gas from the mixed gas 30.

[0150] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0151] (Example 1) First, an emulsion resin composition was prepared by mixing an aqueous emulsion containing a silicone polymer (Shin-Etsu Chemical Co., Ltd., POLON-MF-56), a surface modifier (Daiichi Kogyo Seiyaku Co., Ltd., Neugen LF-40X), and ion-exchanged water for dilution. In the emulsion resin composition, the content of the silicone polymer was 6.0 wt%, and the content of the surface modifier was 0.1 wt%. Next, a porous support was prepared, in which a microporous layer of polysulfone was formed on a polyester nonwoven fabric. A coated film was obtained by coating the prepared emulsion resin composition onto the microporous layer of the porous support using a bar coater. As the porous support, a polysulfone porous substrate (a laminate in which a microporous layer of polysulfone is formed on a polyester nonwoven fabric) manufactured by Nitto Denko Corporation was used. An intermediate layer (thickness 0.20 μm) was formed by drying the obtained coated film at 130°C for 30 seconds.

[0152] Next, a coating solution was prepared by mixing an allyl group-containing polyethylene glycol compound (Sanicol DMT-4175, manufactured by Sanyo Chemical Industries, Ltd.) as compound A, a hydrogen-modified silicone oil (KF-9901, manufactured by Shin-Etsu Chemical Co., Ltd.) as compound B, CAT-PL-50T as a catalyst, and isopropanol (IPA) for dilution, and stirring for 5 minutes. The content of Sanicol DMT-4175 in the solid content excluding the solvent and catalyst, i.e., the content of Sanicol DMT-4175 relative to the total of Sanicol DMT-4175 and KF-9901, was 90.0% by mass, and the content of KF-9901 in the above solid content was 10.0% by mass. The solid content in the coating solution was 2.0% by mass. The catalyst content in the coating solution was 0.1% by mass.

[0153] Next, the prepared coating solution was applied to the above-mentioned intermediate layer using a bar coater to obtain a coating film. Then, the obtained coating film was dried at 130°C for 1 minute to allow the hydrosilylation reaction to proceed, forming a separation functional layer (thickness: 0.15 μm). To remove any unreacted material remaining in the coating film, the obtained separation functional layer was immersed in deionized water for 1 hour. Next, the separation functional layer immersed in water was dried at 60°C for 2 hours to obtain the separation film of Example 1.

[0154] (Example 2) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1.

[0155] Next, a coating solution was obtained in the same manner as in Example 1, except that the content of Sanicol DMT-4175 in the solid content of the coating solution was set to 85% by mass, and the content of KF-9901 in the solid content was set to 15% by mass.

[0156] Using the prepared coating solution, a separation functional layer (thickness: 0.15 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 2.

[0157] (Example 3) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1.

[0158] Next, a coating solution was obtained in the same manner as in Example 1, except that the content of Sanicol DMT-4175 in the solid content of the coating solution was set to 70% by mass, and the content of KF-9901 in the solid content was set to 30% by mass.

[0159] Using the prepared coating solution, a separation functional layer (thickness: 0.15 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 3.

[0160] (Example 4) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1.

[0161] Next, a coating solution was obtained in the same manner as in Example 1, except that the content of Sanicol DMT-4175 and KF-9901 in the solid content of the coating solution was set to 50% by mass each.

[0162] Using the prepared coating solution, a separation functional layer (thickness: 0.15 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 4.

[0163] (Example 5) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1.

[0164] Next, a coating solution was obtained in the same manner as in Example 1, except that the isopropanol in the coating solution was replaced with a mixed solvent of diisopropyl ether (DIPE) and ethyl acetate (EtOAc) (DIPE:EtOAc = 5:5).

[0165] Using the prepared coating solution, a separation functional layer (thickness: 0.15 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 5.

[0166] (Example 6) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1.

[0167] Next, a coating solution was obtained in the same manner as in Example 1, except that the isopropanol in the coating solution was replaced with a mixed solvent of diisopropyl ether (DIPE) and ethyl acetate (EtOAc) (diisopropyl ether:EtOAc = 7:3).

[0168] Using the prepared coating solution, a separation functional layer (thickness: 0.15 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 6.

[0169] (Comparative Example 1) First, a laminate was prepared in which an intermediate layer was formed on a porous support using the same method as in Example 1. Next, a coating solution was prepared by dissolving polyether block amide (PEBAX, manufactured by Arkema) in a mixed solvent of isopropanol and water (isopropanol:water = 7:3).

[0170] Using the prepared coating solution, a separation functional layer (thickness: 0.20 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Comparative Example 1.

[0171] [Gel fraction of the separation functional layer] For Examples 1, 5, and 6, the gel fraction of the separation functional layer was measured as follows.

[0172] The above-mentioned coating solutions used to form the separation functional layer in each example were prepared. After adjusting the amount of solvent so that the solid content of the coating solution was 10.0% by mass, it was poured into a PTFE petri dish. Subsequently, a self-supporting membrane consisting only of the separation functional layer was fabricated by heating at 70°C for 2 hours.

[0173] Approximately 0.1 g of the above-mentioned self-supporting membrane was weighed and used as the sample. The sample was immersed in IPA at room temperature for one day. After that, the sample was removed, the IPA was completely dried, and the sample was weighed again. The gel fraction was calculated from the initial mass M1 and the mass M2 after immersion using the following formula: Gel fraction (%) = (M2 / M1) × 100, where M1 is the initial sample mass and M2 is the sample mass after immersion.

[0174] [Characterization of Separation Membranes] (Gas Permeation Test) Gas permeation tests were performed on the separation membranes prepared in Examples 1 to 6 and Comparative Example 1 using the following method. First, the separation membrane was set in a metal cell and sealed with an O-ring to prevent leakage. Next, carbon dioxide was injected into the metal cell so that it came into contact with the main surface of the separation functional layer side of the separation membrane at a pressure of 0.1 MPa and a temperature of 25°C. As a result, permeated fluid (carbon dioxide) was obtained from the main surface of the porous support side of the separation membrane. The flow rate of the permeated fluid was measured, and from the obtained results, the permeation rate of carbon dioxide T1 CO2 We measured it.

[0175] Furthermore, regarding the fabricated separation membrane, the nitrogen permeation rate T1 N2 The nitrogen permeation rate T1 was measured. N2 Except for using nitrogen at a pressure of 0.1 MPa and a temperature of 25°C instead of carbon dioxide, the carbon dioxide permeation rate T1 CO2 The nitrogen permeation rate T1 was measured using the method described above. Based on the obtained results, the nitrogen permeation rate T1 N2 (GPU) carbon dioxide permeation rate T1 CO2 (GPU) ratio T1 CO2 / T1 N2 The value was calculated and considered as the separation coefficient α1 for carbon dioxide relative to nitrogen.

[0176] (Durability Test I) The separation membranes prepared in Examples 1 to 6 and Comparative Example 1 were subjected to the above-described durability test I. In durability test I, a Smart Bag PA (model AAK-5, capacity 5L) manufactured by GL Sciences Co., Ltd. was used as the gas bag.

[0177] For the separation membrane after durability test I, the carbon dioxide permeation rate T2 was measured using the same method as the gas permeation test described above. CO2 And the nitrogen permeation rate T2 N2 (GPU) was measured. Based on the results obtained, the nitrogen permeation rate T2 was determined. N2 (GPU) carbon dioxide permeation rate T2 CO2 (GPU) ratio T2 CO2 / T2 N2 The following was calculated and the calculated value was considered as the separation coefficient of carbon dioxide relative to nitrogen α2. Furthermore, the permeation rate T1 CO2Transmission rate T2 for (GPU) CO2 (GPU) ratio (ratio T2 CO2 / T1 CO2 ) and the ratio of the separation coefficient α2 to the separation coefficient α1 (ratio α2 / α1) were also calculated.

[0178] (Durability Test II) The separation membranes prepared in Examples 1, 5, and 6 were subjected to the above-described durability test II.

[0179] For the separation membrane after durability test II, the carbon dioxide permeation rate T3 was measured using the same method as in the gas permeation test described above. CO2 And the nitrogen permeation rate T3 N2 (GPU) was measured. Based on the results obtained, the nitrogen permeation rate T3 was determined. N2 Carbon dioxide permeation rate T3 for GPU CO2 (GPU) ratio T3 CO2 / T3 N2 The following was calculated and considered as the separation coefficient α3 of carbon dioxide relative to nitrogen of the separation membrane after durability test II. In addition, the ratio of the separation coefficient α3 to the separation coefficient α1 (ratio α3 / α1) was calculated as the maintenance rate of the separation coefficient α from the initial state. Carbon dioxide permeation rate T CO2 As the maintenance rate, the transmission rate T1 CO2 Transmission rate T3 CO2 The ratio (ratio T3) CO2 / T1 CO2 ) was calculated.

[0180] The results of the gas permeation test and durability test I are shown in Table 1. The results of durability test II are shown in Table 2. In Table 1, "Ratio ether / Si" refers to the ratio of the number of ether structures a to the number of Si atoms.

[0181]

[0182]

[0183] As can be seen from Table 1, the separation membrane of the example, which has a separation functional layer containing a polymer that is a reaction product of compound A having an ether structure a and a carbon-carbon unsaturated bond represented by formula (a) and compound B having a Si-H group, had a higher ratio α2 / α1 compared to the comparative example. From this result, it can be seen that the separation functional layer in the example has high acid resistance and the deterioration of separation performance under acidic conditions is suppressed.

[0184] The separation layer and separation membrane of this embodiment are suitable for separating acidic gases from a gas mixture containing acidic gases. In particular, the separation layer and separation membrane of this embodiment are suitable for separating carbon dioxide from off-gas in chemical plants or thermal power plants.

Claims

1. A separation functional layer comprising a reaction product of a group of compounds including compound A having an ether structure a represented by formula (a) and a carbon-carbon unsaturated bond, and compound B having a Si-H group. In the above formula (a), R 1a is a divalent hydrocarbon group. However, if compound A has a plurality of the ether structures a, then a plurality of R 1a They are independent of each other.

2. The separation functional layer according to claim 1, wherein compound A has at least one unsaturated group having a carbon-carbon unsaturated bond at one of its terminals.

3. The separation functional layer according to claim 1, wherein the compound A is represented by formula (A1). In the above formula (A1), n ​​is an integer greater than or equal to 1, and R 1a X is a divalent hydrocarbon group, and each of the multiple X groups is an unsaturated group having a carbon-carbon unsaturated bond, provided that n is 2 or more, there are multiple R groups. 1a They are independent of each other.

4. The separation functional layer according to claim 1, wherein the divalent hydrocarbon group is an ethane-1,2-diyl group or a propane-1,2-diyl group.

5. The separation functional layer according to claim 1, wherein the compound B includes the structure represented by formula (b). In the above formula (b), R 1b This is a hydrocarbon group which may have a hydrogen atom or a substituent.

6. The separation functional layer according to claim 1, wherein compound B is a polyorganosiloxane having a Si-H group.

7. The separation functional layer according to claim 1, wherein the ratio of the number of ether structures a to the number of Si atoms in the reactant is 6.5 or more.

8. The separation functional layer according to claim 1, wherein the ratio of the number of ether structures a to the number of Si atoms in the reactant is 25.0 or less.

9. The separation functional layer according to claim 1, wherein the reactant has a crosslinked structure.

10. The separation functional layer according to claim 1, used for separating an acidic gas from a gas mixture containing an acidic gas.

11. A separation membrane comprising: a separation functional layer according to any one of claims 1 to 10; and a porous support that supports the separation functional layer.

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