Separation function layer and separation membrane

Abstract

A separation function layer 1 according to the present invention contains a polymer P including a structural unit A derived from an amine compound and a structural unit E derived from an epoxy compound. The epoxy compound includes a polyfunctional epoxy compound having three or more epoxy groups. A separation membrane 10 according to the present invention comprises: the 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. 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 experience a decrease in separation performance when used, washed, or stored under acidic conditions.

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

[0007] The present invention provides a separation functional layer comprising a polymer having structural units derived from an amine compound and structural units derived from an epoxy compound, wherein the epoxy compound comprises a polyfunctional epoxy compound having three or more epoxy groups.

[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 in which the deterioration of separation performance is suppressed can be provided.

[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 the membrane separation apparatus equipped with the separation membrane of the present invention.

[0011] A separation functional layer according to a first aspect of the present invention comprises a polymer having structural units derived from an amine compound and structural units derived from an epoxy compound, wherein the epoxy compound comprises a polyfunctional epoxy compound having three or more epoxy groups.

[0012] In a second embodiment of the present invention, for example, in the separation functional layer according to the first embodiment, the amine compound includes a difunctional amine compound having two amino groups.

[0013] In a third aspect of the present invention, for example, in the separation functional layer according to the second aspect, the difunctional amine compound includes at least one selected from the group consisting of an oxygen atom and a silicon atom.

[0014] In a fourth embodiment of the present invention, for example, in the separation functional layer according to the second or third embodiment, the difunctional amine compound is represented by the following formula (A1). In the above formula (A1), multiple R 1a These are independent of each other and are arbitrary linking elements, where n1 is an integer greater than or equal to 1.

[0015] In a fifth embodiment of the present invention, for example, in the separation functional layer according to the fourth embodiment, a plurality of R 1a These are, independently of each other, a divalent hydrocarbon group or a divalent silicon-containing group.

[0016] In a sixth aspect of the present invention, for example, in the separation functional layer according to the fourth or fifth aspect, a plurality of R 1a These are, independently of each other, an ethane-1,2-diyl group or a propane-1,2-diyl group.

[0017] In a seventh aspect of the present invention, for example, in the separation functional layer according to any one of the first to sixth aspects, the polyfunctional epoxy compound includes a tetrafunctional epoxy compound having four epoxy groups.

[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 tetrafunctional epoxy compound includes at least one selected from the group consisting of oxygen atoms and silicon atoms.

[0019] In a ninth aspect of the present invention, for example, in the separation functional layer according to the seventh or eighth aspect, the tetrafunctional epoxy compound is represented by the following formula (B1). In the formula (B1), a plurality of R 1b are each independently any linking group, and a plurality of R 2b are each independently any linking group, and a plurality of R 3b are each independently a hydrogen atom or any substituent, and a plurality of R 4b are each independently a hydrogen atom or any substituent, and a plurality of R 5b are each independently any linking group or a single bond, and R 6b is any linking group or a single bond, and a plurality of m1 are each independently an integer of 0 or more.

[0020] In a tenth aspect of the present invention, for example, in the separation functional layer according to the ninth aspect, the R 2b is a divalent hydrocarbon group.

[0021] In an eleventh aspect of the present invention, for example, in the separation functional layer according to the ninth or tenth aspect, the m1 is 0.

[0022] In a twelfth aspect of the present invention, for example, in the separation functional layer according to any one of the first to eleventh aspects, the epoxy compound includes a difunctional epoxy compound having two epoxy groups.

[0023] In a thirteenth aspect of the present invention, for example, in the separation functional layer according to the twelfth aspect, the difunctional epoxy compound contains at least one selected from the group consisting of an oxygen atom and a silicon atom.

[0024] In a fourteenth aspect of the present invention, for example, in the separation functional layer according to any one of the twelfth or thirteenth aspect, the difunctional epoxy compound is represented by the following formula (B3). In the formula (B3), R 11b is any linking group, and a plurality of R 12b are each independently any linking group, and a plurality of R 13b are each independently a hydrogen atom or any substituent, and m2 is an integer of 1 or more.

[0025] In the 15th embodiment of the present invention, for example, in the separation functional layer according to the 14th embodiment, the R 11b This is a divalent hydrocarbon group or a divalent silicon-containing group.

[0026] In the sixteenth aspect of the present invention, for example, in the separation functional layer according to the fourteenth or fifteenth aspect, the R 11b This is an ethane-1,2-diyl group or a propane-1,2-diyl group.

[0027] In the seventeenth aspect of the present invention, for example, in the separation functional layer according to any one of the first to sixteenth aspects, the polymer has a crosslinked structure.

[0028] In the eighteenth aspect of the present invention, for example, a separation functional layer according to any one of the first to seventeenth aspects is used to separate an acidic gas from a mixed gas containing an acidic gas.

[0029] A separation membrane according to the 19th aspect of the present invention comprises a separation functional layer according to any one of the first to 18th aspects, and a porous support that supports the separation functional layer.

[0030] 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.

[0031] <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).

[0032] The separation functional layer 1 comprises a polymer P having a constituent unit A derived from an amine compound and a constituent unit E derived from an epoxy compound, wherein the epoxy compound includes a polyfunctional epoxy compound having three or more epoxy groups.

[0033] According to the inventors' studies, polymers (particularly polyether block amides) contained in conventional separation functional layers tend to hydrolyze under acidic conditions, which leads to a decrease in the separation performance of the separation functional layer. Hydrolyzed polymers (low molecular weight components) can leach out of the separation functional layer, causing defects in the layer or affecting structures located near the separation functional layer. For example, in a separation membrane equipped with a separation functional layer and a porous support, the pores of the porous support may become blocked by low molecular weight components leached from the separation functional layer. In contrast, polymer P having the above-mentioned structural units A and E is less susceptible to hydrolysis even under acidic conditions and is suitable for suppressing the decrease in separation performance in the separation functional layer. Furthermore, according to the inventors' studies, polymers containing structural units derived from amine compounds and structural units derived from epoxy compounds in conventional separation functional layers have problems such as a decrease in the separation performance of the separation functional layer because the reaction rate between the amine compound and the epoxy compound, particularly the reaction rate for forming branched structures, is slow, resulting in insufficient crosslinking structure formation and curing failure, or the separation functional layer taking a long time to form and not being able to form a uniform film. In contrast, polymer P, by containing the above-mentioned polyfunctional epoxy compound, incorporates many branched structures, allowing for the formation of a separation functional layer in a shorter time than conventional methods. This makes it suitable for improving initial separation performance and suppressing the deterioration of the separation performance of the separation functional layer.

[0034] An amine compound is a compound having at least one amino group. Preferably, the amine compound includes a difunctional amine compound (diamine) having two amino groups. In this embodiment, it is preferable that the polymer P includes a constituent unit A1 derived from a difunctional amine compound.

[0035] Examples of amino groups contained in a bifunctional amine compound include primary amino groups, secondary amino groups, and tertiary amino groups, with primary amino groups being preferred.

[0036] The molecular weight Mw (or number-average molecular weight in some cases) of the difunctional amine compound is, for example, 200 or more, and may be 300 or more, 400 or more, or even 500 or more. The upper limit of the molecular weight of the difunctional amine compound is, for example, 5000 or less, and may be 4000 or less, 3000 or less, 2500 or less, 2100 or less, or even 2000 or less. The amine equivalent of the difunctional amine compound is, for example, 100 g / eq. to 2000 g / eq., and may be 150 g / eq. to 1500 g / eq. In this specification, amine equivalent means the molecular weight of the amine compound per equivalent of amino groups contained in the amine compound.

[0037] The difunctional amine compound preferably contains at least one atom selected from the group consisting of an oxygen atom and a silicon atom, and is particularly preferably the presence of an oxygen atom. More specifically, the difunctional amine compound preferably has a functional group containing an oxygen atom and a silicon atom. Examples of such functional groups include ether groups and silyl ether groups. In particular, a difunctional amine compound having an ether group is suitable for improving the separation performance of the separation functional layer 1 for acidic gases. A difunctional amine compound having a silyl ether group is suitable for improving the permeation rate of acidic gases that permeate the separation functional layer 1.

[0038] When a difunctional amine compound contains oxygen atoms, the ratio of the number of oxygen atoms to the total number of oxygen atoms and carbon atoms in one molecule of the difunctional amine compound 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.

[0039] The bifunctional amine compound is preferably represented by the following formula (A1).

[0040] In the above formula (A1), multiple R 1a These are independent of each other and are arbitrary linking elements, where n1 is an integer greater than or equal to 1.

[0041] In formula (A1), multiple R1a These may be the same as each other, or they may be different from each other. Multiple R 1a These are preferably independently divalent hydrocarbon groups or divalent silicon-containing groups. The number of carbon atoms in the 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 groups, ethane-1,2-diyl groups, propane-1,2-diyl groups, propane-1,3-diyl groups, and propane-2,2-diyl groups. 1a Preferably, each of them is independently of the other, an ethane-1,2-diyl group or a propane-1,2-diyl group. In formula (A1), 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).

[0042] The divalent silicon-containing group is not particularly limited as long as it contains a silicon atom. The silicon atom contained in the silicon-containing group is R in formula (A1). 1a It may bond with an adjacent oxygen atom (O) to form a silyl ether group. In formula (A1), n1 is 2 or more, and the divalent silicon-containing group is R 1a When bonded to two adjacent oxygen atoms, the divalent silicon-containing group may be represented by the following formula (A2).

[0043] In the above formula (A2), multiple R 2a These are hydrocarbon groups, independently of each other, and * indicates the bond position with the oxygen atom. The number of carbon atoms in the hydrocarbon group is, for example, 1 to 5, and may be 1 to 3. The hydrocarbon group may be linear or branched. Examples of hydrocarbon groups include alkyl groups such as methyl groups and ethyl groups, and methyl groups are preferred.

[0044] In formula (A1), when a divalent silicon-containing group is bonded to an oxygen atom (O) and a nitrogen atom (N), the divalent silicon-containing group may also be represented by the following formula (A3).

[0045] In the above formula (A3), multiple R2a These are, independently of each other, hydrocarbon groups, and R 3a R is a divalent hydrocarbon group, where *1 indicates the bond position with the nitrogen atom, and *2 indicates the bond position with the oxygen atom. 2a Examples of hydrocarbon groups include those described above for formula (A2), and a methyl group is preferred. 3a Examples of the divalent hydrocarbon group include those described above for formula (A1), and a propane-1,3-diyl group is preferred.

[0046] In the above formula (A1), n1 is 1 or greater as described above, and may also be 2 or greater. The upper limit of n1 is, for example, 50 or less, and may also be 40 or less, 30 or less, 20 or less, or even 15 or less.

[0047] Specific examples of difunctional amine compounds include polyoxypropylenediamine (e.g., the "JEFFAMINE" D series from Huntsman), polyoxyethylenediamine, polyetherdiamine having a mixed skeleton of propylene oxide and ethylene oxide (e.g., the "JEFFAMINE" ED series from Huntsman), and other polyetherdiamines in which the terminals of polyols have been modified with amines (e.g., the "KOLFAMINE" series E1100, E2100 from Koei Chemical Co., Ltd.).

[0048] In polymer P, the constituent unit A1 derived from the difunctional amine compound is preferably represented by the following formula (A4). The constituent unit A1 represented by formula (A4) is derived from the difunctional amine compound represented by the above formula (A1).

[0049] In formula (A4), multiple R 1a n1 is the same as in formula (A1). * indicates the bonding position with other atoms in polymer P.

[0050] In polymer P, the ratio of the amount of substance of constituent unit A1 derived from the difunctional amine compound to the amount of substance of all constituent unit A derived from the amine compound is, for example, 10 mol% or more, and may be 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or even 80 mol% or more. The upper limit of this ratio is, for example, 100 mol% or less, and may in some cases be 98 mol% or less, 95 mol% or less, or 90 mol% or less.

[0051] The amine compound may contain a polyfunctional amine compound having three or more amino groups, either together with a difunctional amine compound or in place of the difunctional amine compound. The polyfunctional amine compound can form a polymer P having a crosslinked structure. Examples of amino groups in the polyfunctional amine compound include primary amino groups, secondary amino groups, and tertiary amino groups, with primary amino groups being preferred. The number of amino groups in the polyfunctional amine compound is three or more, preferably four or more.

[0052] The molecular weight (or number-average molecular weight in some cases) of the polyfunctional amine compound is, for example, 100 or more, and may be 500 or more, or even 100,000 or more. The upper limit of the molecular weight of the polyfunctional amine compound is, for example, 100,000 or less, and may be 10,000 or less, 5,000 or less, or even 1,000 or less. The amine equivalent of the polyfunctional amine compound is, for example, 100 g / eq. to 2,000 g / eq., and may be 150 g / eq. to 1,000 g / eq.

[0053] Polyfunctional amine compounds may contain oxygen atoms or silicon atoms, and may have functional groups such as ether groups or silyl ether groups. In particular, it is preferable that polyfunctional amine compounds have ether groups. However, polyfunctional amine compounds may not contain oxygen atoms or silicon atoms.

[0054] When a polyfunctional amine compound contains oxygen atoms, the ratio of the number of oxygen atoms to the total number of oxygen atoms and carbon atoms in one molecule of the polyfunctional amine compound may be, for example, 5% or more, 10% or more, or even 15% or more. The upper limit of this ratio may be, for example, 70% or less, or 40% or less.

[0055] Polyfunctional amine compounds may or may not contain a ring structure. The ring structure may consist only of carbon atoms or may be a heterocyclic ring containing heteroatoms. The ring structure may be monocyclic or polycyclic. The number of carbon atoms in the ring structure is not particularly limited, for example, 3 to 10. Specific examples of ring structures include triazine rings and glycoluryl rings.

[0056] Specific examples of polyfunctional amine compounds include polyethyleneimine, or trimethylolpropane poly(oxypropylene)triamine and glyceryl poly(oxypropylene)triamine (for example, the "JEFFAMINE" T series from HUNTSMAN), polyallylamine (the "PAA" series from Nitto Boseki Co., Ltd.), and other triamines in which the ends of polyols have been modified with amines (for example, the "KOLFAMINE" T03 series from Koei Chemical Co., Ltd.).

[0057] In polymer P, the ratio of the amount of substance of constituent unit A2 derived from the polyfunctional amine compound to the amount of substance of all constituent unit A derived from the amine compound is, for example, 1 mol% or more, and may be 5 mol% or more, 10 mol% or more, or even 20 mol% or more. The upper limit of this ratio is, for example, 50 mol% or less, and may be 30 mol% or less. Polymer P may not contain constituent unit A2.

[0058] The amine compound may include a monofunctional amine compound having one amino group. When polymer P contains structural unit A3 derived from the monofunctional amine compound, the separation performance of the separation functional layer 1 tends to improve. Examples of amino groups included in the monofunctional amine compound include primary amino groups, secondary amino groups, and tertiary amino groups, with primary amino groups being preferred.

[0059] The molecular weight Mw (or number-average molecular weight in some cases) of the monofunctional amine compound is, for example, 100 or more, and may be 300 or more, or even 500 or more. The upper limit of the molecular weight of the monofunctional amine compound is, for example, 5000 or less, and may be 4000 or less, 3000 or less, or even 2500 or less.

[0060] Monofunctional amine compounds may contain oxygen atoms or silicon atoms, and may have functional groups such as ether groups, silyl ether groups, or carboxyl groups. In particular, monofunctional amine compounds are preferably those that have an ether group.

[0061] When a monofunctional amine compound contains oxygen atoms, the ratio of the number of oxygen atoms to the total number of oxygen atoms and carbon atoms in one molecule of the monofunctional amine compound may be, for example, 10% or more, 15% or more, or even 20% or more. The upper limit of this ratio is, for example, 50% or less.

[0062] The monofunctional amine compound is preferably represented by the following formula (A5).

[0063] In the above formula (A5), R 4a R is an arbitrary linking group. 5a is any substituent, and n² is a non-negative integer.

[0064] In formula (A5), if n2 is 1 or greater, multiple R 4a These may be any linking groups, independent of each other. 4a They may be the same as each other, or they may be different from each other. 4a It is preferable that is a divalent hydrocarbon group or a divalent silicon-containing group. Examples of divalent hydrocarbon groups and divalent silicon-containing groups include those described above for formula (A1). In formula (A5), when n2 is 1 or more, all R 4a However, it may also be a divalent hydrocarbon group (especially a propane-1,2-diyl group or an ethane-1,2-diyl group).

[0065] R 5aIn this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those described above for formula (A2). The hydrocarbon group may further have substituents such as carboxyl groups.

[0066] In the above equation (A5), n2 is 0 or greater, as described above, and may be 1 or greater, or 2 or greater. The upper limit of n2 is not particularly limited, for example, 20 or less.

[0067] Specific examples of monofunctional amine compounds include poly(ethylene glycol) methyl etheramine, methoxypoly(oxyethylene / oxypropylene)-2-propylamine (for example, the "JEFFAMINE" M series from HUNTSMAN), and poly(ethylene glycol) 2-aminoethyl ether acetate.

[0068] In polymer P, the ratio of the amount of substance of constituent unit A3 derived from the monofunctional amine compound to the amount of substance of all constituent unit A derived from the amine compound is, for example, 0.1 mol% to 50 mol%, and may also be 1 mol% to 20 mol%. Polymer P may not contain constituent unit A3.

[0069] An epoxy compound is a compound having at least one epoxy group. In this embodiment, the epoxy compound includes a polyfunctional epoxy compound having three or more epoxy groups. That is, polymer P includes a constituent unit E1 derived from the polyfunctional epoxy compound. A polymer P having a crosslinked structure can be formed using the polyfunctional epoxy compound.

[0070] The number of epoxy groups in the polyfunctional epoxy compound may be four or more. The upper limit of the number of epoxy groups is not particularly limited and may be, for example, 10 or less, 8 or less, or even 5 or less.

[0071] The polyfunctional epoxy compound preferably includes a tetrafunctional epoxy compound having four epoxy groups.

[0072] The molecular weight Mw (or number-average molecular weight in some cases) of the tetrafunctional epoxy compound is, for example, 200 to 2000, and may also be 300 to 1500 or 500 to 1100. The epoxy equivalent of the tetrafunctional epoxy compound is, for example, 100 g / eq. to 1000 g / eq., and may also be 200 g / eq. to 500 g / eq. In this specification, epoxy equivalent refers to the molecular weight of the epoxy compound per equivalent of epoxy groups contained in the epoxy compound.

[0073] A tetrafunctional epoxy compound may contain oxygen atoms (specifically, oxygen atoms other than those contained in the epoxy group) and silicon atoms, and may have functional groups such as ether groups and silyl ether groups. It is preferable that the tetrafunctional epoxy compound has an ether group.

[0074] In one molecule of polyfunctional epoxy compound, the ratio of the number of oxygen atoms to the total number of oxygen atoms and carbon atoms may be, for example, 5% to 50%, or 10% to 40%.

[0075] The tetrafunctional epoxy compound is preferably represented by the following formula (B1).

[0076] In equation (B1), multiple R 1b These are independent of each other, arbitrary linking groups, and multiple R 2b These are independent of each other, arbitrary linking groups, and multiple R 3b Each is independently a hydrogen atom or any substituent, and there are multiple R 4b Each is independently a hydrogen atom or any substituent, and there are multiple R 5b These are any linking group or single bond, R 6b m1 is any linking group or single bond, and each of the m1s is an independent integer of 0 or more.

[0077] If m1 is 1 or greater, then multiple R in equation (B1) 1b They may be the same as each other, or they may be different from each other. 1bIt is preferable that this is a divalent hydrocarbon group or a divalent silicon-containing group. Examples of divalent hydrocarbon groups include those described above for formula (A1). 1b It is preferable that it is a methylene group. In formula (B1), all R 1b However, it may also be a divalent hydrocarbon group (especially a methylene group).

[0078] In equation (B1), multiple R 2b These may be the same as each other, or they may be different from each other. Multiple R 2b Preferably, each of these is a divalent hydrocarbon group, independently of the others. Examples of divalent hydrocarbon groups include those described above for formula (A1). In formula (B1), all R 2b It is preferable that the group is a methylene group.

[0079] In equation (B1), multiple R 3b These may be the same as each other, or they may be different from each other. Multiple R in formula (B1) 3b In this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those mentioned above for formula (A2). In formula (B1), all R 3b It is preferable that it is a hydrogen atom.

[0080] In equation (B1), multiple R 4b These may be the same as each other, or they may be different from each other. Multiple R in formula (B1) 4b In this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those mentioned above for formula (A2). In formula (B1), all R 4b It is preferable that it is hydrogen.

[0081] In equation (B1), multiple R 5b These may be the same as each other, or they may be different from each other. Multiple R 5b At least one of them may be a single bond. Multiple R 5b This may be a divalent hydrocarbon group, where one bond is a single bond and the other is a linking group, and may be substituted. The divalent hydrocarbon group may be, for example, a methylene group in which one hydrogen is substituted with a hydroxyl group.

[0082] R 6b R may be a linking group, or a substituted divalent hydrocarbon group. 6b This could be, for example, a methylene group in which one hydrogen atom is substituted by a hydroxyl group.

[0083] In formula (B1), the multiple m1s may be the same or different from each other. In the above formula (B1), m1 is 0 or greater, 2 or greater, and even 3 or greater. The upper limit of m1 is, for example, 15 or less, and may be 10 or less, 5 or less, 4 or less, and even 3 or less. It is preferable that m1 includes 0, and more preferably that all m1s are 0.

[0084] A tetrafunctional epoxy compound may or may not contain ring structures other than epoxy rings. The ring structure may consist only of carbon atoms or may be a heterocycle containing heteroatoms. The ring structure may be monocyclic or polycyclic. The number of carbon atoms in the ring structure is not particularly limited, for example, 3 to 10. Specific examples of ring structures include cyclohexane rings and benzene rings.

[0085] The tetrafunctional epoxy compound may be the EX-500 series, EX-600 series, etc., manufactured by Nagase ChemteX Corporation, or it may be 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (for example, TETRAD-C manufactured by Mitsubishi Gas Chemical Corporation), 4,4'-methylenebis(N,N-diglycidylaniline), etc.

[0086] The tetrafunctional epoxy compound is preferably represented by the following formula (B2).

[0087] In polymer P, the ratio of the amount of substance of constituent unit E1 derived from the tetrafunctional epoxy compound to the amount of substance of all constituent units E derived from the epoxy compound is, for example, 0.1 mol% to 70 mol%, and may be 1 mol% to 60 mol%, or 10 mol% to 50 mol%.

[0088] The epoxy compound may contain, or may not contain, other polyfunctional epoxy compounds together with, or in place of, the tetrafunctional epoxy compound. For example, the epoxy compound may, as a polyfunctional epoxy compound, contain, or in place of, a trifunctional epoxy compound having three epoxy groups together with, or in place of the tetrafunctional epoxy compound.

[0089] The trifunctional epoxy compound may be Denacol EX-300 series, EX-400 series, etc., manufactured by Nagase ChemteX Corporation, or it may be N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline, etc.

[0090] The epoxy compound preferably further comprises a bifunctional epoxy compound having two epoxy groups. In this embodiment, the polymer P preferably contains a constituent unit E2 derived from a bifunctional epoxy compound in addition to a constituent unit E1 derived from a polyfunctional epoxy compound. The epoxy compound may also contain a monofunctional epoxy compound having one epoxy group.

[0091] The molecular weight (or number-average molecular weight in some cases) of the difunctional epoxy compound is, for example, 100 or more, and may be 200 or more, 300 or more, 400 or more, or even 500 or more. The upper limit of the molecular weight of the difunctional epoxy compound is, for example, 2000 or less, and may be 1500 or less, 1300 or less, 1150 or less, 1000 or less, or even 800 or less. The epoxy equivalent of the difunctional epoxy compound is, for example, 100 g / eq. to 1000 g / eq., and may be 200 g / eq. to 500 g / eq.

[0092] The difunctional epoxy compound preferably contains at least one atom selected from the group consisting of oxygen atoms (more specifically, oxygen atoms other than those contained in the epoxy group) and silicon atoms, and is particularly preferably containing an oxygen atom. More specifically, the difunctional epoxy compound preferably has a functional group containing an oxygen atom or a silicon atom in addition to the epoxy group. Examples of such functional groups include ether groups and silyl ether groups. In particular, a difunctional epoxy compound having an ether group is suitable for improving the separation performance of the separation functional layer 1 for acidic gases. A difunctional epoxy compound having a silyl ether group is suitable for improving the permeation rate of acidic gases that permeate the separation functional layer 1.

[0093] In one molecule of a bifunctional epoxy compound, 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 20% or more, 25% or more, 30% or more, or even 35% 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.

[0094] The bifunctional epoxy compound is preferably represented by the following formula (B3).

[0095] In equation (B3), R 11b is an arbitrary linking group, and multiple R 12b These are independent of each other, arbitrary linking groups, and multiple R 13b m2 is an integer greater than or equal to 1, and each atom is independently a hydrogen atom or any substituent.

[0096] In formula (B3), if m² is 2 or more, multiple R 11b These may be any linking groups, independent of each other. 11b They may be the same as each other, or they may be different from each other. 11b It is preferable that this is a divalent hydrocarbon group or a divalent silicon-containing group. Examples of divalent hydrocarbon groups include those described above for formula (A1). 11bIt is preferable that the group is an ethane-1,2-diyl group or a propane-1,2-diyl group. In formula (B1), if m2 is 2 or more, all R 1b However, it may also be a divalent hydrocarbon group (especially an ethane-1,2-diyl group).

[0097] The divalent silicon-containing group is not particularly limited as long as it contains a silicon atom. The silicon atom contained in the silicon-containing group is R in formula (B3). 11b It may bond with an adjacent oxygen atom (O) to form a silyl ether group. In formula (B3), the divalent silicon-containing group may be represented by the following formula (B4) or formula (B5).

[0098] In the above formula (B4), multiple R 14b These are hydrocarbon groups, independently of each other, and * indicates the bond position with the oxygen atom. Examples of hydrocarbon groups include those described above for formula (A2), and a methyl group is preferred.

[0099] In the above formula (B5), multiple R 14b These are, independently of each other, hydrocarbon groups, and R 15b R is a divalent hydrocarbon group, and * indicates the bond position with the oxygen atom. 4b Examples of hydrocarbon groups include those described above for formula (A2), and a methyl group is preferred. 15b Examples of the divalent hydrocarbon group in formula (A1) include those described above, and it is preferably a propane-1,3-diyl group. 15b R in equation (B3) 12b It is preferable that it is bonded to an adjacent oxygen atom.

[0100] In the above formula (B3), multiple R 12b Preferably, each of these is a divalent hydrocarbon group, independently of the others. Examples of divalent hydrocarbon groups include those described above for formula (A1). In formula (B3), all R 12b It is preferable that the group is a methylene group.

[0101] Multiple R's in the above formula (B3) 13bIn this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those mentioned above for formula (A2). In formula (B3), all R 13b It is preferable that it is a hydrogen atom.

[0102] In the above formula (B3), m2 is 1 or greater as described above, and may be 2 or greater, 3 or greater, 4 or greater, 5 or greater, 6 or greater, 7 or greater, 8 or greater, or even 9 or greater. The upper limit of m2 is, for example, 15 or less, and may be 14 or less, 13 or less, 12 or less, 11 or less, or even 10 or less.

[0103] Specific examples of bifunctional epoxy compounds include poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) diglycidyl ether, and poly(dimethylsiloxane) diglycidyl ether.

[0104] In polymer P, examples of constituent units E2 derived from a bifunctional epoxy compound include those represented by formulas (B6) to (B8) below. Constituent units E2 represented by formulas (B6) to (B8) are derived from the bifunctional epoxy compound represented by formula (B3) above.

[0105] In equations (B6) to (B8), R 11b , multiple R 12b , multiple R 13b And m2 is the same as in formula (B3). Multiple R 16b R are, independently of each other, hydrogen atoms or any substituent. 16b In this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those described above for formula (A2). Multiple R 16b R may be a methyl group. When a bifunctional epoxy compound is reacted with an amine compound, R in formulas (B6) to (B8) 16b Normally, this is a hydrogen atom, which together with the adjacent oxygen atom forms a hydroxyl group. After the above reaction, the hydroxyl group is modified, R 16b Substituents can be introduced as such.

[0106] In polymer P, the ratio of the amount of substance of constituent units E2 derived from the bifunctional epoxy compound to the amount of substance of all constituent units E derived from the epoxy compound is, for example, 10 mol% or more, and may be 30 mol% or more, 50 mol% or more, or 30 mol% to 99.9 mol%, 40 mol% to 99 mol%, or 50 mol% to 90 mol%.

[0107] It is preferable that polymer P has both constituent units E2a derived from a difunctional epoxy compound that does not contain silicon atoms and constituent units E2b derived from a difunctional epoxy compound that contains silicon atoms. In polymer P, the ratio of the amount of substance of constituent unit E2a to the amount of substance of all constituent units E2 derived from the difunctional epoxy compound is, for example, 50 mol% to 99 mol%, and may be 70 mol% to 95 mol%. The ratio of the amount of substance of constituent unit E2b to the amount of substance of all constituent units E2 derived from the difunctional epoxy compound is, for example, 1 mol% to 50 mol%, and may be 5 mol% to 30 mol%. Polymer P does not necessarily have to have the above-mentioned constituent unit E2b.

[0108] As described above, the epoxy compound may include a monofunctional epoxy compound having one epoxy group. When polymer P contains a constituent unit E3 derived from a monofunctional epoxy compound, the separation performance of the separation functional layer 1 tends to improve.

[0109] The molecular weight (or number-average molecular weight in some cases) of the monofunctional epoxy compound is, for example, 100 or more, and may be 300 or more, or even 500 or more. The upper limit of the molecular weight of the monofunctional epoxy compound is, for example, 10,000 or less, and may be 5,000 or less, 3,000 or less, or even 1,000 or less.

[0110] Monofunctional epoxy compounds may contain oxygen atoms (specifically, oxygen atoms other than those contained in the epoxy group) or silicon atoms, and may have functional groups such as ether groups, silyl ether groups, or carboxyl groups. In particular, monofunctional epoxy compounds are preferably those that have an ether group.

[0111] When the monofunctional epoxy compound contains an oxygen atom, the ratio of the number of oxygen atoms to the total value of the number of oxygen atoms and the number of carbon atoms in one molecule of the monofunctional epoxy compound is, for example, 10% or more, and may be 15% or more, or even 20% or more. The upper limit of this ratio is, for example, 50% or less.

[0112] The monofunctional epoxy compound is preferably represented by the following formula (B9).

[0113] In the above formula (B9), R 17b is an optional linking group, and R 18b is an optional linking group, and a plurality of R 19b are each independently a hydrogen atom or an optional substituent, R 20b is an optional substituent, and m3 is an integer of 0 or more.

[0114] In formula (B9), when m3 is 2 or more, a plurality of R 17b may each independently be an optional linking group. The plurality of R 17b may be the same as or different from each other. R 17b is preferably a divalent hydrocarbon group or a divalent silicon-containing group. Examples of the divalent hydrocarbon group include those described above for formula (A1). R 17b is preferably an ethane-1,2-diyl group or a propane-1,2-diyl group. In formula (B7), when m3 is 2 or more, all R 17b may be divalent hydrocarbon groups (particularly ethane-1,2-diyl groups). Examples of the divalent silicon-containing group include those described above for formula (B3).

[0115] R 18b is preferably a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include those described above for formula (A1). In formula (B9), R 18b is preferably a methylene group.

[0116] A plurality of R 19bIn this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those mentioned above for formula (A2). In formula (B9), all R 19b It is preferable that it is a hydrogen atom.

[0117] R 20b In this, any substituent is, for example, a hydrocarbon group. Examples of hydrocarbon groups include those described above for formula (A2). The hydrocarbon group may further have substituents such as carboxyl groups.

[0118] In the above formula (B9), m3 is 0 or greater, as described above, and may be 1 or greater, or 2 or greater. There is no particular upper limit to m3, for example, 20 or less.

[0119] In polymer P, the ratio of the amount of substance of constituent unit E3 derived from the monofunctional epoxy compound to the amount of substance of all constituent unit E derived from the epoxy compound is, for example, 0.1 mol% to 50 mol%, and may also be 1 mol% to 20 mol%. Polymer P may not contain constituent unit E3.

[0120] From the viewpoint of improving the mechanical strength of the separation functional layer 1, the polymer P preferably has a crosslinked structure. However, in some cases, the polymer P does not need to have a crosslinked or branched structure.

[0121] Polymer P is typically a reaction product of a group of compounds including amine compounds and epoxy compounds, and may be a polymer formed by a polymerization reaction between an amine compound and an epoxy compound.

[0122] Polymer P typically has functional groups produced by the reaction of an amine compound with an epoxy compound. Examples of these functional groups include amino groups (particularly tertiary and secondary amino groups) and hydroxyl groups. In polymer P, the hydroxyl groups may be modified, thereby being converted into other functional groups such as ether groups.

[0123] Polymer P may further contain other functional groups besides those produced by the reaction of the amine compound and the epoxy compound. Examples of other functional groups include unreacted epoxy groups, amino groups, ether groups, silyl ether groups, and carboxyl groups.

[0124] 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 the intermediate glass transition temperature (T) determined in accordance with the provisions of JIS K7121:1987. mg ) means.

[0125] The gel fraction of polymer P is preferably 50% or more. The upper limit of the gel fraction of polymer P is not particularly limited, and may be, for example, 95% or less, or 90% or less.

[0126] 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.

[0127] The separation functional layer 1 may further contain other components besides polymer P. Examples of other components include other polymers, oligomers, fillers, etc.

[0128] 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.

[0129] (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 including amine compounds and epoxy compounds onto a substrate to form a coating film, and drying the coating film to form a polymer P from the group of compounds.

[0130] The epoxy compounds include polyfunctional epoxy compounds having three or more epoxy groups. Examples of amine compounds and other epoxy compounds included in the compound group are those mentioned above. In the coating solution, some of the compounds in the compound group may have reacted and formed reactants. These reactants make it easier to adjust the viscosity of the coating solution to a range suitable for coating.

[0131] The coating solution preferably contains a reaction product (typically a prepolymer) of a difunctional amine compound, a difunctional epoxy compound, and a polyfunctional epoxy compound (particularly a tetrafunctional epoxy compound). The manufacturing method of this embodiment may further include the steps of: reacting a difunctional amine compound, a difunctional epoxy compound, and a polyfunctional epoxy compound (particularly a tetrafunctional epoxy compound) to form a prepolymer P1; preparing a coating solution containing the prepolymer P1; applying the coating solution onto a substrate to form a coating film; and drying the coating film to form a polymer P from the compound group. The steps of forming the prepolymer P1 and preparing the coating solution containing the prepolymer P1 may be performed simultaneously.

[0132] Prepolymer P1 is typically obtained by crosslinking a reaction product of a difunctional amine compound and a difunctional epoxy compound with a polyfunctional epoxy compound.

[0133] The prepolymer P1 can be formed, for example, by the following method. First, a solution A containing a difunctional amine compound, a difunctional epoxy compound, and a tetrafunctional epoxy compound is prepared. In solution A, the content of the difunctional amine compound is, for example, 0.1 wt% to 40 wt%, the content of the difunctional epoxy compound is, for example, 0.1 wt% to 40 wt%, and the content of the tetrafunctional epoxy compound is, for example, 0.01 wt% to 20 wt%. In solution A, the blending ratio of the difunctional amine compound to the epoxy compound is preferably set such that the ratio of the equivalent amount of amino groups contained in the difunctional amine compound to the equivalent amount of epoxy groups contained in the difunctional epoxy compound is, for example, 0.1 to 2.0, preferably 0.2 to 0.7.

[0134] Solution A preferably further contains a solvent. The solvent is preferably one that has low reactivity with bifunctional amine compounds and epoxy compounds and can dissolve them. Examples of solvents include alcohol compounds such as isopropanol (IPA). The solvent may further contain water. The solvent content in solution A is not particularly limited and may be, for example, 20 wt% to 99 wt%, or 50 wt% to 90 wt%.

[0135] Next, solution A is stirred to react the difunctional amine compound, the difunctional epoxy compound, and the tetrafunctional epoxy compound. This reaction typically involves the reaction between the difunctional amine compound and the difunctional epoxy compound, and the crosslinking reaction of the reactants obtained by this reaction with the tetrafunctional epoxy compound. This forms the prepolymer P1. During the above reaction, solution A may or may not be heated. The above reaction may be carried out at, for example, 60°C to 100°C. The above reaction tends to proceed relatively slowly, and the reaction time may be, for example, 0.5 hours to 15 hours, or even 2 hours to 10 hours.

[0136] The prepolymer P1 typically has a cross-linked structure. Solution A containing this prepolymer P1 can shorten the time required for the film to harden after coating, thereby reducing the occurrence of curing defects and ensuring film uniformity.

[0137] The weight-average molecular weight of prepolymer P1 is not particularly limited as long as it is greater than the molecular weight of the difunctional amine compound, difunctional epoxy compound, or polyfunctional epoxy compound, and is, for example, 1000 or more. The upper limit of the weight-average molecular weight of prepolymer P1 is, for example, 1 million or less. Preferably, the weight-average molecular weight of prepolymer P1 is 10,000 to 100,000.

[0138] A solution containing the prepolymer P1 obtained as described above and a solvent may be used as the coating solution. Examples of solvents for solution A include those described above, with isopropanol being preferred. The solvent content in the coating solution is not particularly limited, and may be, for example, 30 wt% to 99 wt%, or 50 wt% to 99 wt%. Solution A containing the prepolymer P1 obtained as described above may be used as the coating solution, or a solvent may be further mixed with solution A to form the coating solution. The method for preparing the coating solution is not limited to those described above.

[0139] The content of the compound group (amine compounds and epoxy compounds) in the coating solution is, for example, 0.1 wt% to 30 wt%. In the coating solution, the blending ratio of the amine compound and the epoxy compound is preferably set such that the ratio of the equivalent amount of amino groups in the amine compound to the equivalent amount of epoxy groups in the epoxy compound is, for example, 0.1 or more, preferably 0.2 or more, and more preferably 0.3 or more. The upper limit of the above ratio is, for example, 2.0 or less, and may also be 1.0 or less. In the case where a portion of the compound group reacts in the coating solution and a reactant is formed, the above content and blending ratio refer to the values ​​calculated based on the amine compound and epoxy compound used to form the reactant and the unreacted amine compound and epoxy compound. The ratio of the equivalent amount of epoxy groups to the equivalent amount of amino groups is the ratio of the number of epoxy groups to the number of amino groups in the coating solution. The number of epoxy groups is the sum of the number of epoxy groups × moles in one molecule of each epoxy compound contained in the coating solution, and the number of amino groups is the sum of the number of amino groups × moles in one molecule of each amine compound contained in the coating solution. In the coating solution, the ratio of epoxy groups to amino groups is preferably 2:1 to 1:1, and more preferably 2:1.

[0140] 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.

[0141] 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.

[0142] The thickness of the substrate is not particularly limited, and is, for example, 5 μm to 100 μm, preferably 10 μm to 50 μm.

[0143] 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.

[0144] 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 2That 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.

[0145] 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.

[0146] 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.

[0147] In the manufacturing method of this embodiment, as described above, the coated film is dried to form polymer P from the compound group. This yields the separation functional layer 1. It is preferable that polymer P is formed by the complete reaction of the prepolymer P1 described above.

[0148] The drying conditions for the coated film are not particularly limited, as long as polymer P can be formed from the group of compounds. The drying temperature of the coated 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 coated 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.

[0149] 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.

[0150] 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.

[0151] (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.

[0152] <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.

[0153] (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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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%.

[0158] 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.

[0159] 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.

[0160] (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.

[0161] The porous support 3 has an average pore diameter of, for example, 0.01 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.

[0162] (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.

[0163] 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.

[0164] The thickness of the protective layer is not particularly limited, and is, for example, 0.1 μm to 50 μm.

[0165] (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.

[0166] 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.

[0167] 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.

[0168] (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.

[0169] (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 10 GPU or more, 50 GPU or more, 100 GPU or more, and even 150 GPU or more. Transmission velocity T1 CO2 The upper limit is not particularly limited; for example, it may be 5000 GPUs or less, or 1000 GPUs 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.

[0170] Transmission rate T1 CO2This 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.

[0171] The separation coefficient α1 of carbon dioxide relative to nitrogen in the separation membrane 10 is not particularly limited, and may be, for example, 20 or more, 25 or more, 28 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, 60 or less, or even 50 or less.

[0172] 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.

[0173] The separation functional layer 1 of the separation membrane 10 in this embodiment tends to suppress the deterioration of separation performance due to washing. As an example, the ratio of the separation coefficient α2 of carbon dioxide to nitrogen of the separation membrane 10 after the durability test to the separation coefficient α1 of carbon dioxide to nitrogen of the separation membrane 10 before the durability test described below may be, for example, 50% or more, 60% or more, 70% or more, 75% or more, or even 80% or more. The upper limit of this ratio may be, for example, 120% or less, 100% or less, 99% or less, or even 95% or less. Durability test: The separation membrane is immersed in deionized water for 12 hours, and then dried at 60°C for 2 hours.

[0174] 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 the above durability test is performed. CO2 The 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 a durability test against GPU. CO2 The GPU ratio may be, for example, 200% or less, 190% or less, or even 150% or less. The lower limit of this ratio may be, for example, 50% or more, 60% or more, 70% or more, or even 75% or more.

[0175] The separation coefficient α2 of carbon dioxide relative to nitrogen of the separation membrane 10 after durability testing is, for example, 20 or more, and may be 25 or more, 28 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, 60 or less, or even 50 or less.

[0176] 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 a durability test. N2 The 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 (GPU). CO2 (GPU) ratio T2 CO2 / T2 N2 This means: Transmission velocity T2CO2 and T2 N2 Except for using the separation membrane 10 after durability testing, the transmission rate T1 CO2 and T1 N2 This can be measured by the method described above.

[0177] Transmission rate T2 CO2 For example, it may be 10 GPUs or more, 50 GPUs or more, 100 GPUs or more, or even 150 GPUs or more. Transmission velocity T2 CO2 The upper limit may be, for example, 5000 GPUs or less, 1000 GPUs or less, or even 800 GPUs or less.

[0178] <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.

[0179] 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.

[0180] 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%.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] <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.

[0187] 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.

[0188] 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).

[0189] 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.

[0190] 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.

[0191] 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.

[0192] (Example 1) First, an emulsion resin composition was prepared by mixing an aqueous emulsion containing a silicone polymer (POLON-MF-56 manufactured by Shin-Etsu Chemical Co., Ltd.), an aqueous emulsion containing a urethane polymer (Takelac W-6010 manufactured by Mitsui Chemicals, Inc.), and ion-exchanged water for dilution. Next, a coating film was obtained by applying the prepared emulsion resin composition onto a porous support using an applicator (gap: 50 μm). As the porous support, a polysulfone porous substrate manufactured by Nitto Denko Corporation (a laminate in which a microporous layer of polysulfone is formed on a polyester nonwoven fabric) was used. An intermediate layer with a thickness of 1 μm was formed by drying the obtained coating film at 130°C for 10 minutes.

[0193] Next, 0.45 mmol of poly(ethylene glycol) diglycidyl ether (Sigma-Aldrich, number average molecular weight 500) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (Sigma-Aldrich, number average molecular weight 800), as bifunctional epoxy compounds, 0.225 mmol of Denacol EX-614B (Nagase ChemteX), as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-400 (weight average molecular weight approximately 430)), as a bifunctional amine compound, were dissolved in 2.64 g of isopropanol and stirred at 80°C for 4 hours. This operation allowed the reaction between the epoxy compounds and the amine compounds to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. 10.56 g of isopropanol was added to the solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0194] Next, the prepared coating solution was applied to the intermediate layer to a wet thickness of 10 μm to obtain a coating film. Then, the obtained coating film was dried in an oven at 130°C for 0.5 minutes, and then aged for 1 minute to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 1.

[0195] (Example 2) First, a laminate was prepared by forming an intermediate layer on a porous support using the same method as in Example 1. Next, 0.81 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 500) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.045 mmol of Denacol EX-614B (manufactured by Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (manufactured by Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 2.86 g of isopropanol and stirred at 80°C for 4 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. A coating solution was prepared using solution A in the same manner as in Example 1. The concentration of the coating solution was 5 wt%.

[0196] Using the prepared coating solution, a separation functional layer (thickness: 0.5 μm) was formed on the above intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Example 2.

[0197] (Example 3) First, a laminate was prepared by forming an intermediate layer on a porous support using the same method as in Example 1. Next, 0.81 mmol of poly(ethylene glycol) diglycidyl ether (Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.045 mmol of Denacol EX-614B (Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 4.82 g of isopropanol and stirred at 80°C for 8 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. 18.09 g of isopropanol was added to the solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0198] Next, the prepared coating solution was applied to the intermediate layer to a wet thickness of 10 μm to obtain a coating film. Then, the obtained coating film was dried in an oven at 130°C for 1 minute, and then aged for 1 minute to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 3.

[0199] (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. Next, 0.72 mmol of poly(ethylene glycol) diglycidyl ether (Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.09 mmol of Denacol EX-614B (Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 4.50 g of isopropanol and stirred at 80°C for 8 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. 16.87 g of isopropanol was added to the solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0200] Next, the prepared coating solution was applied to the intermediate layer to a wet thickness of 10 μm to obtain a coating film. Then, the obtained coating film was dried in an oven at 130°C for 1 minute to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 4.

[0201] (Example 5) First, a laminate was prepared by forming an intermediate layer on a porous support using the same method as in Example 1. Next, 0.63 mmol of poly(ethylene glycol) diglycidyl ether (Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.135 mmol of Denacol EX-614B (Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 4.18 g of isopropanol and stirred at 80°C for 4 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. A coating solution was prepared by adding 15.66 g of isopropanol to the solution and mixing. The concentration of the coating solution was 5 wt%.

[0202] Next, a coating film was obtained by applying the prepared coating solution onto the above-mentioned intermediate layer to a wet thickness of 10 μm. Then, the obtained coating film was dried in an oven at 130°C for 1 minute to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 5.

[0203] (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. Next, 0.54 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.18 mmol of Denacol EX-614B (manufactured by Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (manufactured by Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 3.85 g of isopropanol and stirred at 80°C for 4 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. A coating solution was prepared by adding 14.45 g of isopropanol to the solution and mixing. The concentration of the coating solution was 5 wt%.

[0204] Using the prepared coating solution, a separation functional layer (thickness: 0.5 μm) was formed on the above intermediate layer in the same manner as in Example 5. This yielded the separation film of Example 6.

[0205] (Example 7) 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, 0.81 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 744) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.045 mmol of Denacol EX-614B (manufactured by Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (manufactured by Huntsman, Jeffamine D-400) as a difunctional amine compound were dissolved in 3.66 g of isopropanol and stirred at 80°C for 4 hours. This operation allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. 13.74 g of isopropanol was added to the solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0206] Using the prepared coating solution, a separation functional layer (thickness: 0.5 μm) was formed on the above intermediate layer in the same manner as in Example 5. This yielded the separation membrane of Example 7.

[0207] (Example 8) 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, 0.45 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.225 mmol of Denacol EX-614B (manufactured by Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of polyoxypropylenediamine (manufactured by Huntsman, JEFFAMINE D-2000 (weight average molecular weight approximately 2000)) as a difunctional amine compound were dissolved in 6.67 g of isopropanol and stirred at 80°C for 4 hours. Through this operation, the reaction between the epoxy compound and the amine compound proceeded, and solution A containing the prepolymer was obtained. Solution A had a concentration of 20 wt%. 25.01 g of isopropanol was added to this solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0208] Next, the prepared coating solution was applied to the intermediate layer to a wet thickness of 10 μm to obtain a coating film. Then, the obtained coating film was dried in an oven at 130°C for 1 minute, and then aged for 20 minutes to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 8.

[0209] (Example 9) The separation membrane of Example 9 was prepared in the same manner as in Example 8, except that poly(propylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 942) was used as the bifunctional epoxy compound.

[0210] (Example 10) First, a laminate was prepared in which an intermediate layer was formed on a porous support by the same method as in Example 1. Next, 0.81 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 1102) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, 0.045 mmol of Denacol EX-614B (manufactured by Nagase ChemteX) as a tetrafunctional epoxy compound, and 0.5 mmol of O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (manufactured by Sigma-Aldrich, weight average molecular weight approximately 600) as a difunctional amine compound were dissolved in 5.16 g of isopropanol and stirred at 80°C for 4 hours. This procedure allowed the reaction between the epoxy compound and the amine compound to proceed, yielding solution A containing the prepolymer. The concentration of solution A was 20 wt%. 19.36 g of isopropanol was added to this solution and mixed to prepare a coating solution. The concentration of the coating solution was 5 wt%.

[0211] Next, the prepared coating solution was applied to the intermediate layer to a wet thickness of 10 μm to obtain a coating film. Then, the obtained coating film was dried in an oven at 130°C for 1 minute, and then aged for 20 minutes to form a separation functional layer (thickness: 0.5 μm). This obtained the separation film of Example 10.

[0212] (Example 11) The separation membrane of Example 11 was prepared in the same manner as in Example 10, except that polyoxypropylenediamine (Huntsman, Jeffamine D-2000) was used as the difunctional amine compound.

[0213] (Example 12) The separation membrane of Example 12 was prepared in the same manner as in Example 8, except that O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (Huntsman, Jeffamine ED-2003) was used as the difunctional amine compound.

[0214] (Example 13) The separation membrane of Example 13 was prepared in the same manner as in Example 8, except that 0.25 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-400) and 0.25 mmol of polyoxypropylenediamine (Huntsman, Jeffamine D-2000) were used as the difunctional amine compounds.

[0215] (Example 14) The separation membrane of Example 14 was prepared in the same manner as in Example 8, except that 0.25 mmol of O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (manufactured by Sigma-Aldrich, weight-average molecular weight approximately 600) and 0.25 mmol of O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (manufactured by Huntsman, JEFFAMINE ED-900) were used as the difunctional amine compounds.

[0216] (Example 15) The separation membrane of Example 15 was prepared in the same manner as in Example 8, except that polyoxyethylenediamine (KOLFAMINE E1100, manufactured by Koei Chemical Co., Ltd.) was used as the difunctional amine compound.

[0217] (Example 16) The separation membrane of Example 16 was prepared in the same manner as in Example 8, except that polyoxyethylenediamine (KOLFAMINE E1100, manufactured by Koei Chemical Co., Ltd.) was used as the difunctional amine compound.

[0218] (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, 0.9 mmol of poly(ethylene glycol) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 500) and 0.1 mmol of poly(dimethylsiloxane) diglycidyl ether (manufactured by Sigma-Aldrich, number average molecular weight 800) as difunctional epoxy compounds, and 0.5 mmol of polyoxypropylenediamine (manufactured by Huntsman, Jeffamine D-400), a difunctional amine compound, were dissolved in 2.96 g of isopropanol and stirred at 80°C for 4 hours. Through this operation, the difunctional epoxy compounds and difunctional amine compounds partially reacted, and a partially reacted product (partially polymerized product) was obtained. This yielded a solution containing the partially reacted product. The concentration of the solution was 20 wt%. A coating solution was prepared using this solution in the same manner as in Example 1. The concentration of the coating solution was 5 wt%.

[0219] Using the prepared coating solution, a separation functional layer (thickness: 0.5 μm) was formed on the above-mentioned intermediate layer in the same manner as in Example 1. This yielded the separation membrane of Comparative Example 1.

[0220] (Comparative Example 2) The separation film of Comparative Example 2 was obtained in the same manner as in Comparative Example 1, except that the separation functional layer was formed by drying the coated film in an oven at 130°C for 0.5 minutes, i.e., aging was not performed.

[0221] [Characterization of Separation Membranes] (Gas Permeation Test) Gas permeation tests were performed on the separation membranes prepared in the examples and comparative examples 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.

[0222] 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 results obtained, 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 of carbon dioxide relative to nitrogen.

[0223] (Durability Test) The separation membranes prepared in the examples and comparative examples were subjected to the durability tests described above.

[0224] For the separation membrane after durability testing, 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 CO2 Transmission rate T2 for (GPU) CO2 The ratio of GPUs and the ratio of the separation coefficient α2 to the separation coefficient α1 were also calculated.

[0225]

[0226] In Table 1, "PPG" represents the polypropylene glycol structure, "PEG" represents the polyethylene glycol structure, "PPG-b-PEG" represents the block copolymer structure of polypropylene glycol and polyethylene glycol, and "PDMS" represents the polydimethylsiloxane structure.

[0227] The blending amounts listed in Table 1 represent the molar ratio of the functional groups in each compound. Here, "functional group amount" means the amount of compound used (mole) multiplied by the number of epoxy groups contained per mole of compound (i.e., 2 or 4) for difunctional epoxy compounds and tetrafunctional epoxy compounds, and the amount of compound used (mole) multiplied by the number of amino groups contained per mole of compound (i.e., 2) for difunctional amine compounds.

[0228] As can be seen from Table 1, the separation membranes of Examples 1 to 16, which had a separation functional layer containing a polymer having structural units derived from an amine compound and structural units derived from an epoxy compound containing a polyfunctional epoxy compound, had a higher ratio α2 / α1 of epoxy compound compared to the comparative example which did not contain a polyfunctional epoxy compound. From this result, it can be seen that the decrease in separation performance was suppressed in the examples.

[0229] The separation membranes of Comparative Examples 1 and 2 had a low ratio α2 / α1, and furthermore, the ratio T2 CO2 / T1 CO2 The result was over 200%. In Comparative Examples 1 and 2, the crosslinking of the separation functional layer did not progress, and it is presumed that the unreacted components and low-crosslinking components that were abundant in the separation functional layer were removed by the durability test, resulting in further defects in the separation functional layer.

[0230] 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-gases in chemical plants or thermal power plants.

Claims

1. A separation functional layer comprising a polymer having structural units derived from an amine compound and structural units derived from an epoxy compound, wherein the epoxy compound comprises a polyfunctional epoxy compound having three or more epoxy groups.

2. The separation functional layer according to claim 1, wherein the amine compound comprises a difunctional amine compound having two amino groups.

3. The separation functional layer according to claim 2, wherein the bifunctional amine compound comprises at least one selected from the group consisting of an oxygen atom and a silicon atom.

4. The separation functional layer according to claim 2, wherein the difunctional amine compound is represented by the following formula (A1). In the above formula (A1), multiple R 1a These are independent of each other and are arbitrary linking elements, where n1 is an integer greater than or equal to 1.

5. Multiple R 1a The separation functional layer according to claim 4, wherein each of the members is independently a divalent hydrocarbon group or a divalent silicon-containing group.

6. Multiple R 1a The separation functional layer according to claim 4, wherein each of the groups is independently an ethane-1,2-diyl group or a propane-1,2-diyl group.

7. The separation functional layer according to claim 1, wherein the polyfunctional epoxy compound comprises a tetrafunctional epoxy compound having four epoxy groups.

8. The separation functional layer according to claim 7, wherein the tetrafunctional epoxy compound comprises at least one selected from the group consisting of oxygen atoms and silicon atoms.

9. The separation functional layer according to claim 7, wherein the tetrafunctional epoxy compound is represented by the following formula (B1). In the formula (B1), a plurality of R 1b are each independently any linking group, and a plurality of R 2b are each independently any linking group, and a plurality of R 3b are each independently a hydrogen atom or any substituent, and a plurality of R 4b are each independently a hydrogen atom or any substituent, and a plurality of R 5b are each independently any linking group or a single bond, and R 6b is any linking group or a single bond, and a plurality of m1 are each independently an integer of 0 or greater.

10. The aforementioned R 2b The separation functional layer according to claim 9, wherein is a divalent hydrocarbon group.

11. The separation functional layer according to claim 9, wherein m1 is 0.

12. The separation functional layer according to claim 1, wherein the epoxy compound comprises a bifunctional epoxy compound having two epoxy groups.

13. The separation functional layer according to claim 12, wherein the bifunctional epoxy compound comprises at least one selected from the group consisting of an oxygen atom and a silicon atom.

14. The separation functional layer according to claim 12, wherein the bifunctional epoxy compound is represented by the following formula (B3). In the above formula (B3), R 11b is an arbitrary linking group, and multiple R 12b These are independent of each other, arbitrary linking groups, and multiple R 13b m2 is an integer greater than or equal to 1, and each atom is independently a hydrogen atom or any substituent.

15. The aforementioned R 11b The separation functional layer according to claim 14, wherein is a divalent hydrocarbon group or a divalent silicon-containing group.

16. The aforementioned R 11b The separation functional layer according to claim 14, wherein is an ethane-1,2-diyl group or a propane-1,2-diyl group.

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

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

19. A separation membrane comprising: a separation functional layer according to any one of claims 1 to 18; and a porous support that supports the separation functional layer.

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