WO2023181893A1

WO2023181893A1 - Separation membrane and method for manufacturing separation membrane

Info

Publication number: WO2023181893A1
Application number: PCT/JP2023/008429
Authority: WO
Inventors: 太一坂巻; 賢輔谷; 和也吉村
Original assignee: 日東電工株式会社
Priority date: 2022-03-22
Filing date: 2023-03-06
Publication date: 2023-09-28

Abstract

The present invention provides a novel separation membrane that is equipped with an intermediate layer and suitable for improving the permeation speed of a permeating fluid. This separation membrane 10 comprises a separation function layer 1, a porous support body 3 supporting the separation function layer 1, and an intermediate layer 2 arranged between the separation function layer 1 and the porous support body 3. The intermediate layer 2 has spaces 6 that are in contact with both the separation function layer 1 and the porous support body 3. The intermediate layer 2 also has a body section 5 joining the separation function layer 1 and the porous support body 3, for example.

Description

Separation membrane and separation membrane manufacturing method

The present invention relates to a separation membrane and a method for manufacturing a separation membrane.

Membrane separation methods have been developed as a method for separating acidic gases from mixed gases containing acidic gases such as carbon dioxide. Membrane separation methods can efficiently separate acidic gases while reducing operating costs, compared to absorption methods in which acidic gases contained in a gas mixture are absorbed by an absorbent and separated.

Examples of separation membranes used in membrane separation methods include composite membranes in which a separation functional layer is formed on a porous support. Examples of the material for the separation functional layer include resins such as polyimide resin and polyether block amide resin. For example,

Patent Documents

1 and 2 disclose separation membranes containing polyimide resin.

Japanese Patent Application Publication No. 2014-184424 JP 2014-24004 Publication

In the field of separation membranes, an intermediate layer is sometimes placed between the separation functional layer and the porous support. According to the intermediate layer, a separation functional layer with a small thickness can be easily formed. However, a separation membrane including an intermediate layer has room for improvement in terms of the permeation rate of the permeate fluid from the separation membrane.

Therefore, the present invention provides a new separation membrane that is equipped with an intermediate layer and is suitable for improving the permeation rate of a permeate fluid.

The present invention
a separation functional layer;
a porous support supporting the separation functional layer;
an intermediate layer disposed between the separation functional layer and the porous support;
Equipped with
The intermediate layer provides a separation membrane having a space in contact with both the separation functional layer and the porous support.

Furthermore, the present invention
A method for producing a separation membrane comprising a separation functional layer, a porous support supporting the separation functional layer, and an intermediate layer disposed between the separation functional layer and the porous support. There it is,
The manufacturing method includes:
A second laminate having the release liner, the separation functional layer, and the intermediate layer in this order is formed by forming the intermediate layer having a space on the first laminate having the release liner and the separation functional layer. to form a
bonding the intermediate layer of the second laminate to the porous support so that the space contacts both the separation functional layer and the porous support to form a third laminate;
removing the release liner from the third laminate;
Provided is a method for manufacturing a separation membrane, including:

According to the present invention, it is possible to provide a new separation membrane that includes an intermediate layer and is suitable for improving the permeation rate of a permeate fluid.

FIG. 2 is a schematic cross-sectional view of a separation membrane according to an embodiment of the present invention when cut in the thickness direction. FIG. 3 is a schematic cross-sectional view of the intermediate layer included in the separation membrane, which is observed when the intermediate layer is cut parallel to the surface of the intermediate layer. FIG. 7 is a schematic cross-sectional view of an intermediate layer included in a separation membrane according to a modified example, which is observed when the intermediate layer is cut parallel to the surface of the intermediate layer. FIG. 7 is a schematic cross-sectional view of an intermediate layer included in a separation membrane according to another modified example, which is observed when the intermediate layer is cut parallel to the surface of the intermediate layer. FIG. 7 is a plan view of an intermediate layer included in a separation membrane according to another modification. FIG. 3 is a diagram for explaining a method for manufacturing a separation membrane. FIG. 3 is a diagram for explaining a method for manufacturing a separation membrane. FIG. 3 is a diagram for explaining a method for manufacturing a separation membrane. 1 is a schematic cross-sectional view of a membrane separation device equipped with a separation membrane of the present invention. FIG. 3 is a perspective view schematically showing a modified example of a membrane separation device equipped with the separation membrane of the present invention.

The separation membrane according to the first aspect of the present invention is
a separation functional layer;
a porous support supporting the separation functional layer;
an intermediate layer disposed between the separation functional layer and the porous support;
Equipped with
The intermediate layer has a space in contact with both the separation functional layer and the porous support.

In the second aspect of the present invention, for example, in the separation membrane according to the first aspect, the intermediate layer has a main body portion that joins the separation functional layer and the porous support.

In the third aspect of the present invention, for example, in the separation membrane according to the second aspect, the main body portion has a stripe shape, a dot shape, a mesh shape, or a fibrous shape in plan view.

In the fourth aspect of the present invention, for example, in the separation membrane according to the second or third aspect, the main body portion includes an adhesive portion formed from an adhesive composition.

In the fifth aspect of the present invention, for example, in the separation membrane according to the fourth aspect, the adhesive composition is at least one selected from the group consisting of a silicone polymer, a (meth)acrylic polymer, and a rubber polymer. including.

In a sixth aspect of the present invention, for example, in the separation membrane according to any one of the first to fifth aspects, when the intermediate layer is viewed in plan, the space exists on the surface of the intermediate layer. The area ratio of the region is 40% or more.

In the seventh aspect of the present invention, for example, in the separation membrane according to any one of the first to sixth aspects, the intermediate layer has a thickness of 0.1 μm or more.

In the eighth aspect of the present invention, for example, in the separation membrane according to any one of the first to seventh aspects, the separation functional layer contains a polyimide resin.

In the ninth aspect of the present invention, for example, the separation membrane according to any one of the first to eighth aspects is used to separate carbon dioxide from a mixed gas containing carbon dioxide and nitrogen.

The method for manufacturing a separation membrane according to the tenth aspect of the present invention includes:
A method for producing a separation membrane comprising a separation functional layer, a porous support supporting the separation functional layer, and an intermediate layer disposed between the separation functional layer and the porous support. There it is,
The manufacturing method includes:
A second laminate having the release liner, the separation functional layer, and the intermediate layer in this order is formed by forming the intermediate layer having a space on the first laminate having the release liner and the separation functional layer. to form a
bonding the intermediate layer of the second laminate to the porous support so that the space contacts both the separation functional layer and the porous support to form a third laminate;
removing the release liner from the third laminate;
including.

The details of the present invention will be described below, but the following description is not intended to limit the present invention to specific embodiments.

<Embodiment of separation membrane>
As shown in FIG. 1, the separation membrane 10 of this embodiment includes a separation functional layer 1, an intermediate layer 2, and a porous support 3. The porous support 3 supports the separation functional layer 1 via the intermediate layer 2. The intermediate layer 2 is arranged between the separation functional layer 1 and the porous support 3 and is in direct contact with each of the separation functional layer 1 and the porous support 3. The intermediate layer 2 has a space 6 in contact with both the separation functional layer 1 and the porous support 3. For example, the intermediate layer 2 further includes a main body portion 5 that joins the separation functional layer 1 and the porous support 3 together with the space 6 .

(separation functional layer)
The separation functional layer 1 is, for example, a layer that can preferentially transmit an acidic gas contained in a mixed gas. In one preferred form, the separation functional layer 1 contains resin. Examples of the resin contained in the separation functional layer 1 include polyether block amide resin, polyamide resin, polyether resin, polyimide resin, cellulose acetate resin, silicone resin, and fluororesin. Separation functional layer 1 preferably contains polyimide resin.

The polymer contained in the polyimide resin is not particularly limited, and includes, for example, polyimide P having a structural unit represented by the following formula (1). In formula (1), X and Y are linking groups. Examples of polyimide P include those described in

Patent Document

1 or 2.

The structural unit of formula (1) may be a structural unit represented by the following formula (2).

In formula (2), X ¹ and Y ¹ are linking groups. X ¹ includes, for example, at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom, and a silicon atom, preferably includes at least one selected from the group consisting of an oxygen atom and a nitrogen atom, and more preferably contains an oxygen atom. X ¹ contains, for example, at least one functional group selected from the group consisting of an ether group, an ester group, a ketone group, a hydroxyl group, an amide group, a thioether group, and a sulfonyl group, and preferably consists of an ether group and an ester group. At least one selected from the group.

X ¹ may contain other groups, such as hydrocarbon groups, in addition to the above-mentioned functional groups. The number of carbon atoms in the hydrocarbon group is not particularly limited, but is, for example, 1 to 15. The number of carbon atoms may be 1 to 3 or 6 to 15. Although there is no restriction on the valence of the hydrocarbon group, a divalent hydrocarbon group is preferable. Examples of divalent hydrocarbon groups include methylene group, ethylene group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,4-diyl group, and pentane-1,5-diyl group. Diyl group, 2,2-dimethylpropane-1,3-diyl group, 1,4-phenylene group, 2,5-di-tert-butyl-1,4-phenylene group, 1-methyl-1,1-ethanediylbis (1,4-phenylene) group and biphenyl-4,4'-diyl group. Furthermore, at least one hydrogen atom contained in these hydrocarbon groups may be substituted with a halogen atom.

X ¹ is, for example, a linking group represented by the general formula -O-R ⁷ -O- or the general formula -COO-R ⁸ -OOC-. Here, R ⁷ and R ⁸ are divalent hydrocarbon groups having 1 to 15 carbon atoms. Examples of the divalent hydrocarbon group include those mentioned above.

X ¹ does not need to contain the above-mentioned functional group. Examples of such X ¹ include an alkylene group. The number of carbon atoms in the alkylene group is not particularly limited, and may be, for example, from 1 to 15, or from 1 to 5. Although the alkylene group may be branched, it is preferably linear. Although some of the hydrogen atoms of the alkylene group may be substituted with halogen atoms, it is preferable that the alkylene group is in an unsubstituted state, that is, it is a linear or branched alkylene group itself.

Y ¹ includes, for example, at least one selected from the group consisting of oxygen atoms, nitrogen atoms, sulfur atoms, and silicon atoms, preferably includes at least one selected from the group consisting of oxygen atoms and nitrogen atoms, and more preferably contains an oxygen atom. Y ¹ contains, for example, at least one functional group selected from the group consisting of an ether group, an ester group, a ketone group, a hydroxyl group, an amide group, a thioether group, and a sulfonyl group, and preferably contains an ether group.

Y ¹ may contain other groups, such as hydrocarbon groups, in addition to the above-mentioned functional groups. Examples of the hydrocarbon group include those mentioned above for X ¹ . Y ¹ may be the same as or different from X ¹ .

In formula (2), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a sulfonic acid group, an alkoxy group having 1 to 30 carbon atoms, or a hydrocarbon having 1 to 30 carbon atoms. It is the basis. R ¹ to R ⁶ are preferably hydrogen atoms. The alkoxy group or hydrocarbon group of R ¹ to R ⁶ may be either linear or branched. The number of carbon atoms in the alkoxy group or hydrocarbon group is preferably 1 to 20, more preferably 1 to 10, particularly preferably 1 to 5. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the hydrocarbon group include a methyl group, an ethyl group, and a propyl group. At least one hydrogen atom contained in the alkoxy group or hydrocarbon group may be substituted with a halogen atom.

R ² and R ³ and R ⁵ and R ⁶ may be bonded to each other to form a ring structure. The ring structure is, for example, a benzene ring.

In formula (2), Ar ¹ and Ar ² are divalent aromatic groups. Divalent aromatic groups include aromatic rings. In formula (2), the nitrogen atom of the phthalimide structure is preferably directly bonded to the aromatic ring contained in Ar ¹ or the aromatic ring contained in Ar ² . In formula (2), Y ¹ may be directly bonded to each of the aromatic ring contained in Ar ¹ and the aromatic ring contained in Ar ² .

In Ar ¹ and Ar ² , the aromatic ring is preferably composed of carbon atoms. However, the aromatic ring may be a heteroaromatic ring containing a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom. Although the aromatic ring may be polycyclic, it is preferably monocyclic. The number of carbon atoms in the aromatic ring is not particularly limited, and may be, for example, 4 to 14 or 6 to 10. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a furan ring, a pyrrole ring, a pyridine ring, and a thiophene ring.

In Ar ¹ and Ar ² , the aromatic ring may have no substituent or may have a substituent. Examples of substituents on the aromatic ring include halogen atoms, hydroxyl groups, sulfonic acid groups, alkoxy groups having 1 to 30 carbon atoms, and hydrocarbon groups having 1 to 30 carbon atoms. Examples of the alkoxy group and hydrocarbon group include those mentioned above for R ¹ to R ⁶ . When the aromatic ring has a plurality of substituents, the plurality of substituents may be the same or different. Ar ¹ and Ar ² are preferably a phenylene group which may have a substituent or a naphthalenediyl group which may have a substituent.

The separation functional layer 1 preferably consists essentially of resin. As used herein, "consisting essentially of" means to the exclusion of other components that alter the essential characteristics of the mentioned material, e.g. 95 wt% or more, even 99 wt% or more of the material It means that it is composed of. However, the separation functional layer 1 may further contain additives such as a leveling agent in addition to the resin.

In another preferred form, the separation functional layer 1 contains an ionic liquid. The separation functional layer 1 has, for example, a double network gel containing an ionic liquid. A double network gel is a gel that has two types of network structures that are independent of each other. The double network gel includes, for example, a first network structure mainly composed of an organic material, a second network structure mainly composed of an inorganic material, and an ionic liquid. As used herein, "consisting primarily" means that 50 wt% or more, and further 70 wt% or more, of the material is comprised.

The organic material for forming the first network structure includes, for example, a polymer such as polyacrylamide (particularly polydialkyl acrylamide such as polydimethylacrylamide). The polymer contained in the organic material has a structural unit derived from an acrylamide derivative, and may further include a crosslinked structure. A polymer containing a crosslinked structure can be produced by a known method. For example, first, a prepolymer having a structural unit having an N-hydroxysuccinimide ester group is prepared. The structural unit having an N-hydroxysuccinimide ester group is derived from, for example, N-acryloxysuccinimide. Next, a polymer containing a crosslinked structure can be obtained by reacting the prepolymer with an amine crosslinking agent. Amine-based crosslinking agents are compounds having two or more primary amino groups, such as ethylene glycol bis(3-aminopropyl) ether.

The second network structure may include a network of multiple particles. A network of a plurality of particles is formed, for example, by a plurality of particles bonding to each other through hydrogen bonds. The particles included in the second network structure may contain an inorganic material or an organic material. Examples of inorganic materials contained in the particles include silica, titania, and alumina. As an example, the particles included in the second network structure are silica particles.

In this embodiment, examples of the ionic liquid include an ionic liquid having imidazolium, pyridinium, ammonium, or phosphonium and a substituent having 1 or more carbon atoms.

In the ionic liquid having imidazolium and a substituent having 1 or more carbon atoms, the substituent having 1 or more carbon atoms includes an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and a cycloalkyl group having 3 to 14 carbon atoms. Examples include aryl groups having 6 to 20 carbon atoms, which may be further substituted with hydroxy groups, cyano groups, amino groups, monovalent ether groups, etc. (for example, hydroxyalkyl groups having 1 to 20 carbon atoms). etc).

Examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n- Nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n- Nonadecyl group, n-eicosadecyl group, i-propyl group, sec-butyl group, i-butyl group, 1-methylbutyl group, 1-ethylpropyl group, 2-methylbutyl group, i-pentyl group, neopentyl group, 1,2 -dimethylpropyl group, 1,1-dimethylpropyl group, t-pentyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, etc., and these include hydroxyl group, cyano group, amino group, monovalent group, etc. It may be substituted with an ether group or the like.

The above alkyl group may be substituted with a cycloalkyl group. The number of carbon atoms in the alkyl group substituted with the cycloalkyl group is, for example, 1 or more and 20 or less. Examples of the alkyl group substituted with a cycloalkyl group include a cyclopropylmethyl group, a cyclobutylmethyl group, a cyclohexylmethyl group, a cyclohexylpropyl group, etc., and these include a hydroxy group, a cyano group, an amino group, a monovalent ether It may be substituted with a group or the like.

Examples of the cycloalkyl group having 3 to 14 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, norbornyl group, bornyl group, adamantyl group, etc. , these may be further substituted with a hydroxy group, a cyano group, an amino group, a monovalent ether group, etc.

Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, tolyl group, xylyl group, mesityl group, anisyl group, naphthyl group, benzyl group, etc. These include hydroxy group, cyano group, amino group, It may be substituted with a valent ether group or the like.

Imidazolium and a compound having a substituent having 1 or more carbon atoms may further have a substituent such as an alkyl group, and may form a salt with a counter anion. Counter anions include alkyl sulfate, tosylate, methanesulfonate, acetate, bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, thiocyanate, dicyanamide, tricyanomethanide, tetracyanoborate, hexafluorophosphate, tetrafluoro Examples include borates and halides, and from the viewpoint of gas separation performance, bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, dicyanamide, tricyanomethanide, and tetracyanoborate are preferred.

Examples of imidazolium and ionic liquids having a substituent having one or more carbon atoms include 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide and 1-ethyl-3-methylimidazolium dicyanamide. , 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1 -Butyl-3-methylimidazolium trifluoromethanesphonate, 1-butyl-3-methylimidazolium tetrachloroferrate, 1-butyl-3-methylimidazolium iodide, 1-butyl-2,3-dimethylimidazolium Chloride, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1 -Butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium trifluoro(trifluoromethyl)borate, 1-butyl-3-methylimidazolium tribromide, 1, 3-dimesitylimidazolium chloride, 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride, 1,3-diisopropylimidazolium tetrafluoroborate, 1,3-di-tert-butylimidazolium tetrafluoro Borate, 1,3-dicyclohexylimidazolium tetrafluoroborate, 1,3-dicyclohexylimidazolium chloride, 1,2-dimethyl-3-propylimidazolium iodide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl -3-Methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium bromide, 1-methyl-3-propylimidazolium iodide, 1-methyl- 3-n-octylimidazolium bromide, 1-methyl-3-n-octylimidazolium chloride, 1-methyl-3-n-octylimidazolium hexafluorophosphate, 1-methyl-3-[6-(methylsulfinyl) Examples include hexyl]imidazolium p-toluenesulfonate, 1-ethyl-3-methylimidazolium tricyanomethanide, and 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

Among them, from the viewpoint of gas separation performance, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide ([EMI][FSI]), 1-ethyl-3-methylimidazolium dicyanamide ([EMI] [DCA]), 1-ethyl-3-methylimidazolium tricyanomethanide ([EMI][TCM]), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C ₄ mim][ TF ₂ N]), 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C ₂ OHim][TF ₂ N]) is particularly preferred.

The method for producing the double network gel is not particularly limited, and for example, the method disclosed in E. Kamio et al., Adv. Mater, 29, 1704118 (2017) can be used.

The content of the ionic liquid in the double network gel is, for example, 50 wt% or more, preferably 60 wt% or more, more preferably 70 wt% or more, and still more preferably 80 wt% or more. The higher the ionic liquid content, the more the separation functional layer 1 can preferentially transmit the acidic gas contained in the mixed gas. The upper limit of the ionic liquid content is not particularly limited, and is, for example, 95 wt%.

The content of the first network structure mainly composed of an organic material in the double network gel is, for example, 1 wt% or more, preferably 5 wt% or more, and more preferably 10 wt% or more. The upper limit of the content of the first network structure is, for example, 15 wt%. The content of the second network structure mainly composed of an inorganic material in the double network gel is, for example, 1 wt % or more from the viewpoint of improving the strength of the double network gel. The upper limit of the content of the second network structure is, for example, 5 wt%. The ratio of the total value of the weight of the first network structure and the weight of the second network structure to the weight of the double network gel is, for example, 2 wt% or more, preferably 5 wt% or more, and more preferably 10 wt% or more. . This ratio is preferably 20 wt% or less. In this form, the separation functional layer 1 preferably consists essentially of a double network gel.

The thickness of the separation functional layer 1 is, for example, 50 μm or less, preferably 25 μm or less, and more preferably 15 μm or less. Depending on the case, the thickness of the separation functional layer 1 may be 10 μm or less, 5.0 μm or less, or 2.0 μm or less. The thickness of the separation functional layer 1 may be 0.05 μm or more, or 0.1 μm or more.

(middle class)
As described above, the intermediate layer 2 has the space 6 and may further include the main body portion 5. Specifically, the space 6 penetrates the intermediate layer 2 in the thickness direction and can function as a flow path for the fluid that has passed through the separation functional layer 1 (permeated fluid). The main body part 5 includes, for example, an adhesive part formed from an adhesive composition, and joins the separation functional layer 1 and the porous support 3. As an example, the intermediate layer 2 has a plurality of main body parts 5, and a space 6 as a void is formed between the plurality of main body parts 5. However, the space 6 may be formed to surround the main body portion 5. The space 6 may be a through hole formed in the main body portion 5.

The main body portion 5 may or may not be arranged in a predetermined pattern. As an example, the main body portion 5 may have a stripe shape, a dot shape, a mesh shape (mesh shape), or a fibrous shape in plan view.

2A to 2C show that in the separation membrane 10, the intermediate layer 2 is cut parallel to the surface of the intermediate layer 2, and the cross section is taken in a direction from the intermediate layer 2 toward the porous support 3 (a third direction Z to be described later). FIG. FIG. 2D is a plan view obtained when the separation functional layer 1 is removed from the separation membrane 10 and the intermediate layer 2 is observed in the third direction Z. In detail, FIGS. 1 and 2A show an example of the separation membrane 10, and show the main body portions 5 arranged in a stripe shape in a plan view. FIG. 2B shows a separation membrane 10 according to a modified example, and shows the main body portion 5 arranged in a dot shape in a plan view. FIG. 2C shows a separation membrane 10 according to another modification, and shows the main body portion 5 arranged in a mesh shape in a plan view. FIG. 2D shows a separation membrane 10 according to another modification, and shows a main body portion 5 that is fibrous.

[Striped main body]
Hereinafter, with reference to FIGS. 1 and 2A, the intermediate layer 2 having the main body portions 5 arranged in a striped shape in a plan view will be described. In the example shown in FIGS. 1 and 2A, the main body portion 5 has a band shape extending in the first direction X. In the example shown in FIGS. The main body portion 5 extends straight in the first direction X, for example. The first direction X is, for example, a direction from one of the pair of end surfaces of the porous support 3 toward the other.

As an example, the cross-sectional shape of the main body portion 5 observed when the intermediate layer 2 is cut in the thickness direction is substantially rectangular (FIG. 1). Furthermore, the cross-sectional shape of the main body portion 5 observed when the intermediate layer 2 is cut parallel to the surface of the intermediate layer 2 is also substantially rectangular (FIG. 2A). In this specification, "substantially rectangular" means that when the cross section of the main body 5 is observed, the ratio of the area of the main body 5 to the area of the smallest right-angled quadrangle surrounding the main body 5 is 70%. or more, preferably 90% or more.

In the example shown in FIGS. 1 and 2A, the intermediate layer 2 has a plurality of main body parts 5. The shapes and dimensions of the plurality of main bodies 5 may be different from each other or may be substantially the same. As an example, the plurality of main bodies 5 each extend in the first direction X and are lined up in the second direction Y orthogonal to the first direction X. The plurality of main body parts 5 may be lined up in the second direction Y at substantially equal intervals. Note that the second direction Y is, for example, a direction from one of the other pair of end surfaces of the porous support 3 to the other. Note that the third direction Z, which is orthogonal to each of the first direction X and the second direction Y, is a direction from the intermediate layer 2 to the porous support 3 and coincides with the thickness direction of the separation membrane 10.

In the intermediate layer 2, a space 6 as a void is formed between the two main body parts 5. The space 6 extends in the direction in which the main body portion 5 extends (first direction X). Like the main body part 5, the space 6 extends straight in the first direction X, for example. As an example, the cross-sectional shape of the space 6 observed when the intermediate layer 2 is cut in the thickness direction is substantially rectangular (FIG. 1). Furthermore, the cross-sectional shape of the space 6 observed when the intermediate layer 2 is cut parallel to the surface of the intermediate layer 2 is also substantially rectangular (FIG. 2A).

A plurality of spaces 6 are formed in the intermediate layer 2. The shapes and dimensions of the plurality of spaces 6 may be different from each other or may be substantially the same. As an example, the plurality of spaces 6 each extend in the first direction X and are lined up in the second direction Y. The plurality of spaces 6 may be lined up in the second direction Y at substantially equal intervals. The plurality of main body parts 5 and the plurality of spaces 6 are arranged alternately in the second direction Y, for example.

1 and 2A show a plurality of

main body parts

5a, 5b, 5c, 5d and 5e, and a plurality of

spaces

6a, 6b, 6c and 6d, which the intermediate layer 2 has. A plurality of main body portions 5a to 5e and a plurality of spaces 6a to 6d are arranged alternately in the second direction Y. In FIGS. 1 and 2A, a plurality of main body portions 5a to 5e are lined up in the second direction Y at equal intervals. The plurality of spaces 6a to 6d are also arranged at equal intervals in the second direction Y.

In the examples shown in FIGS. 1 and 2A, the dimensions of the main body 5 and the spaces 6 and the number of the main body 5 and the spaces 6 are not particularly limited, and can be adjusted as appropriate depending on the characteristics of the intended separation membrane 10. can do.

[Dot-shaped main body]
Below, with reference to FIG. 2B, the intermediate layer 2 having the main body portions 5 arranged in a dot shape when viewed from above will be described. In the example shown in FIG. 2B, the main body portion 5 has a cylindrical shape extending in the third direction Z. However, the main body portion 5 may have a prismatic shape.

In the example shown in FIG. 2B, the intermediate layer 2 has a plurality of main body parts 5. The shapes and dimensions of the plurality of main bodies 5 may be different from each other or may be substantially the same. The plurality of main body parts 5 may be arranged randomly, or may be arranged in a matrix in the first direction X and the second direction Y. In this specification, "matrix shape" includes a lattice shape and a staggered shape. In the intermediate layer 2, a space 6 is formed to surround each of the plurality of main body parts 5.

In the example shown in FIG. 2B, the dimensions of the main body portions 5 and the number of the main body portions 5 are not particularly limited, and can be adjusted as appropriate depending on the intended characteristics of the separation membrane 10.

[Mesh-like main body]
Below, with reference to FIG. 2C, the intermediate layer 2 having the main body portion 5 arranged in a mesh shape in a plan view will be described. In the example shown in FIG. 2C, the main body portion 5 has a first portion in the shape of a band extending in the first direction X and a second portion in the shape of a band extending in the second direction Y. A mesh is formed by intersecting the first portion and the second portion. This mesh corresponds to the space 6.

The main body portion 5 has a plurality of first portions extending in the first direction X, and further has a plurality of second portions extending in the second direction Y. The shapes and dimensions of the plurality of first portions and second portions may be different from each other or may be substantially the same.

In the example shown in FIG. 2C, the shape and dimensions of the main body 5 and the number of spaces 6 are not particularly limited, and can be adjusted as appropriate depending on the intended characteristics of the separation membrane 10.

[Fibrous main body]
In the following, the intermediate layer 2 having the fibrous main body portion 5 will be described with reference to FIG. 2D. The fibrous main body portion 5 may be in the form of short fibers or long fibers. The fibrous main body portion 5 may have a branched structure.

In the example shown in FIG. 2D, the intermediate layer 2 has a plurality of main body parts 5. The shape of the nonwoven fabric is formed by a plurality of main body parts 5 coming together. In the intermediate layer 2, spaces 6 are formed between the plurality of main body parts 5. The space 6 is, for example, a continuous hole formed three-dimensionally.

In the example shown in FIG. 2D, the shape and dimensions of the main body portion 5 are not particularly limited, and can be adjusted as appropriate depending on the intended characteristics of the separation membrane 10.

[Aperture ratio]
When the intermediate layer 2 is viewed in plan (for example, when the intermediate layer 2 is observed in the third direction Z), the area ratio R of the region where the spaces 6 exist on the surface of the intermediate layer 2 is, for example, 20 % or more, and may be 40% or more, 50% or more, 60% or more, 70% or more, or even 80% or more. The higher the ratio R is, the higher the permeation rate of the permeate fluid from the separation membrane 10 tends to be. The upper limit of the ratio R is, for example, 90% or less, from the viewpoint of the bonding strength between the separation functional layer 1 and the porous support 3 by the intermediate layer 2, and the ease of manufacturing the separation membrane 10 by the transfer method. In some cases, it may be 80% or less, or 70% or less. In this specification, the "ratio R" may be referred to as the aperture ratio.

[Material of main body]
As described above, the main body portion 5 includes, for example, an adhesive portion formed from an adhesive composition. The main body part 5 including the adhesive part is suitable for joining the separation functional layer 1 and the porous support 3. The main body part 5 may be comprised only of an adhesive part, or may further include other components (for example, a base material) other than the adhesive part. As an example, the main body part 5 may be a double-sided tape including a base material and adhesive parts formed on each of two main surfaces of the base material. However, the main body portion 5 does not need to include the adhesive portion as long as the separation functional layer 1 and the porous support 3 can be bonded together. The main body portion 5 may include an adhesive portion made of adhesive.

The adhesive composition includes, for example, at least one selected from the group consisting of silicone polymers, (meth)acrylic polymers, and rubber polymers. A silicone polymer means a polymer having a structural unit containing a siloxane bond. In this specification, an adhesive composition containing a silicone polymer may be referred to as a "silicone adhesive."

Examples of silicone adhesives include peroxide-crosslinked silicone adhesives, addition reaction type silicone adhesives, and active energy ray-curable silicone adhesives. The peroxide-crosslinked silicone adhesive contains an organic peroxide (eg, benzoyl peroxide). This organic peroxide causes radical crosslinking. Examples of addition reaction type silicone adhesives include hydrosilylation type silicone adhesives. The hydrosilylated silicone adhesive contains a SiH group-containing siloxane crosslinking agent and a platinum catalyst. Crosslinking occurs through the hydrosilylation reaction using this platinum-based catalyst. In active energy ray-curable silicone adhesives, a crosslinking reaction progresses when exposed to light such as ultraviolet rays or electron beams. Particularly, addition reaction type silicone adhesives, such as hydrosilylation type silicone adhesives, are preferred from the viewpoints of not leaving a residue in the intermediate layer 2, being able to react at low temperatures, and improving reaction speed.

The silicone-based pressure-sensitive adhesive preferably contains a silicone resin component and a silicone gum component as the silicone-based polymer, since the adhesiveness, peelability, and cohesiveness can be easily controlled.

The silicone resin component is not particularly limited, but is preferably a branched polyorganosiloxane containing a hydroxyl group bonded to a silicon atom in its molecule, and includes M units (R ₃ SiO _1/2 ), Q units (SiO ₂ ), More preferably, it is a polyorganosiloxane having at least one unit selected from the group consisting of T units (RSiO _3/2 ) and D units (R ₂ SiO). In the above-mentioned units, R are independently of each other a monovalent hydrocarbon group or a hydroxyl group. Examples of the monovalent hydrocarbon group include an alkyl group (eg, methyl group, ethyl group, propyl group, etc.), an alkenyl group (eg, vinyl group, etc.), and an aryl group (eg, phenyl group, etc.). In particular, the silicone resin component is preferably an MQ resin composed of M units (R ₃ SiO _1/2 ) and Q units (SiO ₂ ). The silicone resin components may be used alone or in combination of two or more.

The silicone gum component is not particularly limited, but is preferably a linear polyorganosiloxane represented by the following formula (3).

In formula (3), R is independently a methyl group, a phenyl group, or an alkenyl group. n is 100 to 10,000. The silicone gum components may be used alone or in combination of two or more.

In the peroxide-crosslinked silicone adhesive, the silicone gum component described above preferably contains a methyl group. In peroxide-crosslinked silicone adhesives, the methyl groups of the silicone gum component are radically crosslinked. In the hydrosilylated silicone adhesive, the silicone gum component preferably contains an alkenyl group, particularly a vinyl group. In hydrosilylation-type silicone pressure-sensitive adhesives, alkenyl groups in silicone gum components are crosslinked by a hydrosilylation reaction.

The silicone adhesive may further contain additives in addition to the silicone resin component and silicone gum component. Examples of additives include materials for advancing the crosslinking reaction (organic peroxides, SiH group-containing siloxane crosslinking agents, platinum catalysts, etc.), adhesion improvers (for example, X-92- manufactured by Shin-Etsu Chemical Co., Ltd. 185), silane coupling agents, fillers, plasticizers, anti-aging agents, antistatic agents, colorants (pigments, dyes), fillers and tackifiers described below. The additives may be used alone or in combination of two or more.

The silicone adhesive may further contain an organic solvent (for example, toluene, xylene, etc.).

Specific examples of silicone adhesives include "KR-3700", "KR-3701", and "KR-3704" manufactured by Shin-Etsu Chemical Co., Ltd. These commercial products are provided as products containing both a silicone gum component and a silicone resin component. The silicone adhesive may include a mixture of these commercially available products.

The (meth)acrylic polymer has, for example, a structural unit derived from alkyl (meth)acrylate as a main component. As used herein, "(meth)acrylate" means acrylate and/or methacrylate. In this specification, an adhesive composition containing a (meth)acrylic polymer may be referred to as a "(meth)acrylic adhesive."

The alkyl group contained in the alkyl (meth)acrylate is not particularly limited, and is, for example, a linear, branched, or cyclic alkyl group having 2 to 14 carbon atoms.

Examples of the alkyl (meth)acrylate include acrylic acid alkyl esters having an alkyl group having 2 to 14 carbon atoms, preferably acrylic acid alkyl esters having an alkyl group having 4 to 9 carbon atoms. Examples of acrylic acid alkyl esters include n-butyl acrylate, isobutyl acrylate, s-butyl acrylate, isoamyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate. , nonyl acrylate, isononyl acrylate, and the like.

The alkyl (meth)acrylate may be, for example, a methacrylic acid alkyl ester having an alkyl group having 2 to 14 carbon atoms, preferably a methacrylic acid alkyl ester having an alkyl group having 2 to 10 carbon atoms. Examples of methacrylic acid alkyl esters include ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, and methacrylate. Examples include cyclohexyl acid, bornyl methacrylate, and isobornyl methacrylate.

The alkyl (meth)acrylates mentioned above can be used alone or in combination of two or more. The content of structural units derived from alkyl (meth)acrylate in the (meth)acrylic polymer is not particularly limited, and is, for example, 70 to 100 wt%, preferably 85 to 99 wt%, more preferably 87 to 99 wt%. %.

The (meth)acrylic polymer may further contain a structural unit derived from a copolymerizable monomer copolymerizable with an alkyl (meth)acrylate. Examples of copolymerizable monomers include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; Alkyl (meth)acrylates having 15 or more alkyl groups; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; styrenic monomers such as styrene; (meth) Epoxy group-containing monomers such as glycidyl acrylate and methylglycidyl (meth)acrylate; (meth)acrylates containing hydroxyl groups such as 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl acrylate; (meth)acrylate; Acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane Nitrogen-containing monomers such as (meth)acrylamide, (meth)acryloylmorpholine, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; ( Alkoxy group-containing monomers such as methoxyethyl meth)acrylate and ethoxyethyl (meth)acrylate; Cyano group-containing monomers such as acrylonitrile and methacrylonitrile; Functional monomers such as 2-methacryloyloxyethyl isocyanate; ethylene, propylene, isoprene , butadiene, isobutylene and other olefinic monomers; vinyl ether and other monomers; halogen atom-containing monomers such as vinyl chloride; N-vinylpyrrolidone, N-(1-methylvinyl)pyrrolidone, N-vinylpyridine, N-vinylpiperidone, Vinyl group-containing heterocyclic compounds such as N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine; N-vinylcarboxylic acid amide; Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N- - Itaconimide monomers such as 2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, N- Succinimide monomers such as (meth)acryloyl-8-oxyoctamethylene succinimide; styrene sulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl ( Sulfonic acid group-containing monomers such as meth)acrylate and (meth)acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate , glycol-based acrylic ester monomers such as methoxypolypropylene glycol (meth)acrylate; acrylic ester monomers containing heterocycles or halogen atoms such as tetrahydrofurfuryl (meth)acrylate and fluorine (meth)acrylate; ethylene glycol di (meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, etc. or poly)alkylene glycol di(meth)acrylate; neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, penta Esterified products of (meth)acrylic acid and polyhydric alcohols such as erythritol tri(meth)acrylate and dipentaerythritol hexa(meth)acrylate; polyfunctional vinyl compounds such as divinylbenzene; allyl (meth)acrylate, (meth)acrylate; Examples include compounds having reactive unsaturated double bonds such as vinyl acrylate.

The (meth)acrylic adhesive may further contain additives and organic solvents in addition to the (meth)acrylic polymer. Examples of additives and organic solvents include those mentioned above for silicone adhesives.

A rubber-based polymer means a polymer that exhibits rubber elasticity in a temperature range around room temperature (25°C). In this specification, an adhesive composition containing a rubber-based polymer may be referred to as a "rubber-based adhesive."

The rubber-based polymer includes, for example, at least one selected from the group consisting of natural rubber, synthetic rubber, and thermoplastic elastomer. Synthetic rubbers include polyisobutylene (PIB), butadiene rubber (BR), butyl rubber (IIR), isoprene rubber (IR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), Examples include butadiene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, and the like.

Examples of thermoplastic elastomers include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), and styrene. - Ethylene-propylene-styrene block copolymer (SEPS, hydrogenated product of SIS), styrene-ethylene-propylene block copolymer (SEP, hydrogenated product of styrene-isoprene block copolymer), styrene-isobutylene-styrene Styrenic thermoplastic elastomers (styrene block copolymers) such as block copolymers (SIBS); polyurethane thermoplastic elastomers; polyester thermoplastic elastomers; polymer blends of polypropylene and EPT (ternary ethylene-propylene rubber), etc. Examples include thermoplastic elastomer blends.

The rubber-based adhesive may further contain additives and organic solvents in addition to the rubber-based polymer. Examples of additives and organic solvents include those mentioned above for silicone adhesives.

The main body part 5 (or adhesive part) can be produced, for example, by removing the organic solvent from the adhesive composition. Therefore, the main body portion 5 contains components derived from the adhesive composition. As an example, the main body portion 5 includes at least one selected from the group consisting of a silicone polymer, a (meth)acrylic polymer, and a rubber polymer. Note that the silicone-based polymer contained in the main body portion 5 may be a crosslinked product of a silicone-based polymer contained in the adhesive composition. Similarly, the (meth)acrylic polymer contained in the main body portion 5 may be a crosslinked product of (meth)acrylic polymer contained in the adhesive composition.

In the main body part 5 (or adhesive part), the content of the above polymers (silicone polymer, (meth)acrylic polymer, and rubber polymer) is not particularly limited, and is, for example, 60 wt% or more, preferably 70 wt%. % or more, more preferably 90 wt% or more. The body portion 5 may consist essentially of the above-mentioned polymer.

The main body part 5 (or the adhesive part) may further contain the above-mentioned additives, especially fillers. The main body portion 5 containing the filler is suitable for improving the permeation rate of acid gas in the separation membrane 10. The filler may contain an inorganic material or an organic material. Examples of inorganic materials contained in the filler include zeolite, silica, titania, and alumina. Examples of organic materials include (meth)acrylic polymers.

The filler may include a metal-organic-framework (MOF). The metal-organic framework is also called a porous coordination polymer (PCP). Metal-organic frameworks include, for example, metal ions and organic ligands. Examples of metal ions include Cu ions and Zn ions. The organic ligand includes, for example, an aromatic ring. Examples of the aromatic ring contained in the organic ligand include a benzene ring and an imidazole ring. Examples of the organic ligand include trimesic acid and 2-methylimidazole. Specific examples of the metal-organic framework include HKUST-1 and ZIF-8.

The shape of the filler is typically particulate. In this specification, particulate includes spherical, ellipsoidal, scaly, fibrous, and the like.

The average particle diameter of the filler is not particularly limited, and may be, for example, 5 μm or less, 1 μm or less, 800 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, or even 100 nm or less. The lower limit of the average particle diameter of the filler is, for example, 1 nm. The average particle size of the filler can be determined by the following method. First, a cross section of the main body portion 5 is observed using 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 regarded as the particle diameter (particle diameter) of that particular filler. The particle diameter of an arbitrary number of fillers (at least 50) is calculated, and the average value of the calculated values is regarded as the average particle diameter of the filler.

The filler content in the main body portion 5 (or adhesive portion) is, for example, 40 wt% or less, and may be 30 wt% or less, 20 wt% or less, or even 10 wt% or less. The lower limit of the filler content in the main body portion 5 is not particularly limited, but from the viewpoint of improving the permeation rate of acidic gas, it is, for example, 1 wt%.

[Physical properties of intermediate layer]
The thickness of the intermediate layer 2 (or the thickness of the main body portion 5) is, for example, 0.1 μm or more, 0.3 μm or more, 0.5 μm or more, 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 30 μm or more, It may be 50 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, or even 200 μm or more. The intermediate layer 2 having a large thickness tends to be able to bond the separation functional layer 1 and the porous support 3 with sufficient strength. The upper limit of the thickness of the intermediate layer 2 is not particularly limited, and is, for example, 500 μm. The thickness of the intermediate layer 2 is preferably 5 to 50 μm. Note that in conventional separation membranes, as the thickness of the intermediate layer increases, the permeation rate of the permeated fluid from the separation membrane tends to decrease. On the other hand, in the separation membrane 10 of this embodiment, since the intermediate layer 2 has the spaces 6, even if the thickness of the intermediate layer 2 increases, the permeation rate of the permeated fluid from the separation membrane 10 is unlikely to decrease.

The storage modulus of the intermediate layer 2 at 25° C. is, for example, 1.0×10 ⁵ Pa or less, preferably 0.95×10 ⁵ Pa or less, and may be 0.90×10 ⁵ Pa or less. , 0.85×10 ⁵ Pa or less. The lower the storage modulus of the intermediate layer 2, the more the adhesive strength of the intermediate layer 2 tends to increase. The storage modulus of the intermediate layer 2 at 25° C. is preferably 0.1×10 ⁵ Pa or more.

The storage modulus of the intermediate layer 2 at 25° C. can be determined by the following method. First, a measurement sample made of a material constituting the intermediate layer 2 is prepared. The shape of the sample for measurement is a disk. The measurement sample has a bottom diameter of 8 mm and a thickness of 2 mm. Next, dynamic viscoelasticity measurement is performed on the measurement sample. For dynamic viscoelasticity measurement, for example, "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific can be used. From the results of the dynamic viscoelasticity measurement, the storage modulus of the intermediate layer 2 at 25° C. can be determined. Note that the conditions for dynamic viscoelasticity measurement are as follows.
・Measurement conditions Frequency: 1Hz
Deformation mode: Torsion Measurement temperature: -70℃~150℃
Heating rate: 5℃/min

(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 material containing at least one selected from the group consisting of polyvinyl fluoride, polyvinylidene fluoride, polyurethane, polypropylene, polyethylene, polycarbonate, polysulfone, polyetheretherketone, polyacrylonitrile, polyimide, and polyphenylene oxide; Porous) polymers; metal foams with open cells or closed cells; polymer foams with open cells or closed cells; silica; porous glass; mesh screens and the like. The porous support 3 may be a combination of two or more of these. Preferably, the porous support 3 contains at least one member selected from the group consisting of polyvinylidene fluoride (PVDF) and polysulfone (PSF).

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, and 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.

(Separation membrane manufacturing method)
The separation membrane 10 of this embodiment is easily manufactured by a so-called transfer method. 3A to 3C are diagrams for explaining a method for manufacturing the separation membrane 10 of this embodiment by a transfer method. As shown in FIGS. 3A to 3C, the manufacturing method of this embodiment includes forming an intermediate layer 2 having a space 6 on a first laminate 15 having a release liner 9 and a separation functional layer 1. Forming a second laminate 16 having a release liner 9, a separation functional layer 1, and an intermediate layer 2 in this order, and forming a second laminate 16 having a release liner 9, a separation functional layer 1, and an intermediate layer 2 in this order; It includes laminating the intermediate layer 2 of the laminate 16 with the porous support 3 to form a third laminate 17 and removing the release liner 9 from the third laminate 17.

The first laminate 15 can be produced, for example, by the following method. First, a coating liquid containing the material for the separation functional layer 1 is prepared. The coating liquid may contain a highly polar organic solvent such as N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc). Such organic solvents are suitable for dissolving polyimide resins. The coating liquid may further contain a leveling agent for improving the coating properties of the coating liquid. Next, this coating liquid is applied onto the release liner 9 to obtain a coating film. By drying this coating film, the separation functional layer 1 can be formed. Thereby, the first laminate 15 having the release liner 9 and the separation functional layer 1 can be obtained (FIG. 3A).

Examples of the release liner 9 include a film containing resin; paper; and a sheet containing a metal material such as aluminum or stainless steel. Sheets containing metallic materials tend to have high heat resistance. The release liner 9 is preferably a film containing resin because of its excellent surface smoothness. In the release liner 9, polymers contained in the resin include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, and polymethylpentene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyvinyl chloride, and vinyl chloride copolymer. Polyesters; polyurethanes; ethylene-vinyl acetate copolymers and the like; polyesters, particularly polyethylene terephthalate, are preferred.

The surface of the release liner 9 may be subjected to a release treatment. The release treatment can be performed, for example, by applying a release treatment agent to the surface of the release liner 9. Examples of the release agent include a silicone release agent, a long-chain alkyl release agent, a fluorine release agent, and a molybdenum sulfide release agent. The release agent may be used alone or in combination of two or more. The release liner 9 is preferably a release-treated polyethylene terephthalate (PET) film.

The thickness of the release liner 9 is not particularly limited, and is, for example, 5 to 300 μm, preferably 50 to 200 μm.

The method of applying the coating liquid onto the release liner 9 is not particularly limited, and for example, a spin coating method, a dip coating method, etc. can be used. The coating liquid may be applied using a wire bar or the like. The coating film can be dried, for example, under heating conditions. The heating temperature of the coating film is, for example, 50°C or higher, preferably 130 to 150°C. The heating time for the coating film is, for example, 1 minute or more, may be 5 minutes or more, or may be 30 minutes or more.

The second laminate 16 can be produced, for example, by the following method. First, a double-sided tape that can function as the intermediate layer 2 (specifically, the main body part 5) is prepared. The double-sided tape has, for example, an adhesive portion formed from an adhesive composition. Next, this double-sided tape is placed on the separation functional layer 1 in the first laminate 15. The double-sided tape is arranged so that a space 6 is formed. By placing the double-sided tape on the separation functional layer 1, a main body (double-sided tape) 5 and a space 6 are formed, and the intermediate layer 2 is obtained. Thereby, it is possible to obtain a second laminate 16 having the release liner 9, the separation functional layer 1, and the intermediate layer 2 in this order (FIG. 3B). In the second laminate 16 , the intermediate layer 2 is exposed to the outside of the second laminate 16 .

Note that the method for manufacturing the second laminate 16 is not limited to the above method. For example, the intermediate layer 2 is formed by applying a coating liquid (for example, an adhesive composition) containing the material of the intermediate layer 2 (specifically, the main body part 5) onto the separation functional layer 1 and drying it. , the second laminate 16 may be manufactured. In this manufacturing method, the coating liquid is applied so that a space 6 is formed. The coating liquid can be applied by a method using a mask having an opening at a position where the main body portion 5 is to be formed, a flexographic printing method, a screen printing method, a die coating method, a spray coating method, or the like. The coating liquid can be dried, for example, under heating conditions. For example, when the coating liquid is an addition reaction type silicone adhesive, the coating liquid may be dried by heating at 100 to 130°C. Under the above-mentioned heating conditions, the coating liquid is dried and, for example, a crosslinking reaction of the silicone polymer proceeds to form a crosslinked product of the silicone polymer. The heating time of the coating liquid is, for example, 1 minute or more, and may be 5 minutes or more.

Next, the intermediate layer 2 of the second laminate 16 is bonded to the porous support 3 so that the space 6 of the intermediate layer 2 is in contact with both the separation functional layer 1 and the porous support 3, thereby forming a third laminate. A body 17 can be obtained (FIG. 3C). The method of bonding the intermediate layer 2 to the porous support 3 is not particularly limited, and any known method can be used. For example, the intermediate layer 2 and the porous support 3 can be bonded together by overlapping the intermediate layer 2 and the porous support 3 and pressing them together by moving a roller back and forth. The separation membrane 10 can be obtained by removing the release liner 9 from the third laminate 17 (FIG. 1).

Note that the method for producing the separation membrane 10 is not limited to the transfer method described with reference to FIGS. 3A to 3C, and the separation functional layer 1 can be directly produced on the laminate of the intermediate layer 2 and the porous support 3. You may also use the direct method. However, in the direct method, a coating liquid containing the material of the separation functional layer 1 is applied onto the laminate of the intermediate layer 2 and the porous support 3, and the resulting coating film is dried. Create. Therefore, depending on the solvent contained in the coating liquid, the intermediate layer 2 that comes into contact with the coating liquid may dissolve. When the intermediate layer 2 is dissolved, the coating liquid may also come into contact with the porous support 3 and further dissolve the porous support 3. When the intermediate layer 2 and the porous support 3 are dissolved, the permeation rate of the permeated fluid from the separation membrane 10 tends to decrease. In the transfer method, since the separation functional layer 1 can be produced without applying a coating liquid onto the intermediate layer 2, it is possible to prevent the intermediate layer 2 and the porous support 3 from being dissolved by the coating liquid.

(Shape of 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, for example, may be a hollow fiber membrane.

(Characteristics of separation membrane)
In the separation membrane 10, the intermediate layer 2 having the spaces 6 tends to improve the permeation rate of the permeate fluid. As an example, the permeation rate T of carbon dioxide passing through the separation membrane 10 is, for example, 50 GPU or more, and may be 100 GPU or more, 150 GPU or more, 200 GPU or more, or even 250 GPU or more. The upper limit of the transmission rate T is not particularly limited, and is, for example, 1000 GPU. Note that GPU means 10 ⁻⁶ ·cm ³ (STP)/(sec·cm ² ·cmHg). cm ³ (STP) means the volume of carbon dioxide at 1 atmosphere and 0°C.

The permeation rate T can be calculated by the following method. First, a mixed gas consisting of carbon dioxide and nitrogen is supplied to a space adjacent to one surface of the separation membrane 10 (for example, the main surface 11 on the separation functional layer side of the separation membrane 10), and the other surface of the separation membrane 10 is supplied with a gas mixture consisting of carbon dioxide and nitrogen. (For example, the space adjacent to the main surface 12 of the separation membrane 10 on the porous support side) is depressurized. Thereby, a permeated fluid that has passed through the separation membrane 10 is obtained. The weight of the permeate fluid and the volume proportions of carbon dioxide and nitrogen in the permeate fluid are determined. The transmission rate T can be calculated from the measurement results. In the above operation, the concentration of carbon dioxide in the mixed gas is 50 vol% under standard conditions (0° C., 101 kPa). The mixed gas supplied to the space adjacent to one surface of the separation membrane 10 has a temperature of 30° C. and a pressure of 0.1 MPa. The space adjacent to the other surface of the separation membrane 10 is reduced in pressure so that the pressure in the space is 0.1 MPa lower than the atmospheric pressure in the measurement environment.

The permeation rate T of carbon dioxide that permeates through the separation membrane 10 relative to the permeation rate T ₀ (GPU) of carbon dioxide that permeates the measurement separation membrane that has the same configuration as the separation membrane 10 except that it does not include the intermediate layer 2 (GPU) ratio T/T ₀ is, for example, 20% or more, 40% or more, 50% or more, 70% or more, 80% or more, 90% or more, 95% or more, and even 99% or more. Good too. Note that the permeation rate T ₀ can be measured by the method described above for the permeation rate T. The measurement separation membrane can be produced by the method described in Reference Example 1 described later.

Under the above measurement conditions for the permeation rate T, the separation coefficient α of carbon dioxide with respect to nitrogen of the separation membrane 10 is not particularly limited, and is, for example, 20 or more, preferably 25 or more. The upper limit of the separation coefficient α is not particularly limited, and is, for example, 50. The separation coefficient α can be calculated from the following formula. However, in the following formula, X _A and X _B are the volume ratio of carbon dioxide and the volume ratio of nitrogen in the mixed gas, respectively. Y _A and Y _B are the volume ratio of carbon dioxide and the volume ratio of nitrogen in the permeate fluid that has passed through the separation membrane 10, respectively.
Separation coefficient α=(Y _A /Y _B )/(X _A /X _B )

(Applications of separation membrane)
Applications of the separation membrane 10 of this embodiment include applications for separating acidic gas from a mixed gas containing acidic gas. Examples of the mixed acidic gas include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, and nitrogen oxides (NOx), with carbon dioxide being preferred. The mixed gas contains gases other than acidic gas. Other gases include, for example, nonpolar gases such as hydrogen and nitrogen, and inert gases such as helium, with nitrogen being preferred. In particular, the separation membrane 10 of this embodiment is suitable for use in separating carbon dioxide from a mixed gas containing carbon dioxide and nitrogen. However, the use of the separation membrane 10 is not limited to the use of separating acidic gas from the above-mentioned mixed gas.

<Embodiment of membrane separation device>
As shown in FIG. 4, the membrane separation apparatus 100 of this embodiment includes a separation membrane 10 and a tank 20. The tank 20 includes a first chamber 21 and a second chamber 22. Separation membrane 10 is arranged inside tank 20. Inside the tank 20, the separation membrane 10 separates a first chamber 21 and a second chamber 22. The separation membrane 10 extends from one of the pair of wall surfaces of the tank 20 to the other.

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, the outlet 21b, and the outlet 22a is an opening formed in the wall surface of the tank 20, for example.

Membrane separation using the membrane separation device 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 acidic gas in the mixed gas 30 is not particularly limited, and in a standard state is, for example, 0.01 vol% (100 ppm) or more, preferably 1 vol% or more, more preferably 10 vol% or more, and even more preferably is 30 vol% or more, particularly preferably 50 vol% or more. The upper limit of the concentration of acidic gas in the mixed gas 30 is not particularly limited, and is, for example, 90 vol% in a standard state.

The pressure inside the first chamber 21 may be increased by supplying the mixed gas 30. The membrane separator 100 may further include a pump (not shown) for pressurizing 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.

The pressure inside the second chamber 22 may be reduced while the mixed gas 30 is supplied to the first chamber 21. The membrane separator 100 may further include a pump (not shown) for reducing the pressure inside the second chamber 22. The pressure in the second chamber 22 may be reduced so that the space within the second chamber 22 is, for example, 10 kPa or more, preferably 50 kPa or more, more preferably 100 kPa or more smaller than the atmospheric pressure in the measurement environment.

By supplying the mixed gas 30 into the first chamber 21, it is possible to obtain a permeate fluid 35 having a higher content of acidic gas than the mixed gas 30 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 contains, for example, acidic gas as a main component. However, the permeate fluid 35 may contain a small amount of gas other than acidic gas. Permeate fluid 35 is discharged to the outside of tank 20 through outlet 22a.

The concentration of acidic gas in the mixed gas 30 gradually decreases from the inlet 21a of the first chamber 21 toward the outlet 21b. The mixed gas 30 (non-permeable fluid 36) treated in the first chamber 21 is discharged to the outside of the tank 20 through the outlet 21b.

The membrane separation apparatus 100 of this embodiment is suitable for a flow type (continuous type) membrane separation method. However, the membrane separation apparatus 100 of this embodiment may be used in a batch-type membrane separation method.

<Modified example of membrane separation device>
The membrane separation device 100 may be a spiral membrane element, a hollow fiber membrane element, or the like. Figure 5 shows a spiral-shaped membrane element. The membrane separation device 110 in FIG. 5 includes a central tube 41 and a stacked body 42. The laminate 42 includes the separation membrane 10.

The central tube 41 has a cylindrical shape. A plurality of holes are formed on the surface of the center tube 41 to allow the permeate fluid 35 to flow into the center tube 41 . Examples of materials for the center tube 41 include resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyphenylene ether resin (PPE resin), and polysulfone resin (PSF resin); metals such as stainless steel and titanium. It will be done. The inner diameter of the central tube 41 is, for example, in the range of 20 to 100 mm.

In addition to the separation membrane 10, the laminate 42 further includes a supply side channel material 43 and a permeate side channel material 44. The laminate 42 is wound around the central tube 41. The membrane separation device 110 may further include an exterior material (not shown).

As 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.

Membrane separation using the membrane separation device 110 is performed, for example, by the following method. First, the mixed gas 30 is supplied to one end of the wound laminate 42 . The permeated fluid 35 that has passed 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 central pipe 41. The mixed gas 30 (non-permeable fluid 36) processed by the membrane separator 110 is discharged to the outside from the other end of the wound stack 42. Thereby, the acidic gas can be separated from the mixed gas 30.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Reference example 1)
[Preparation of separation membrane]
First, as a tetracarboxylic dianhydride, bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)ethylene (25.12 g, 60 mmol) was prepared, and as a diamine compound, 4,4 '-Diamino diphenyl ether (12.26 g, 60 mmol) was prepared. Next, the diamine compound was dissolved in N-methyl-2-pyrrolidone to obtain a solution. Polyamic acid was obtained by adding tetracarboxylic dianhydride to the obtained solution under room temperature conditions. Next, the polyamic acid was chemically imidized using triethylamine (1.56 g, 15.4 mmol) and acetic anhydride (9.44 g, 92.5 mmol). Chemical imidization was performed in N-methyl-2-pyrrolidone at 60°C. The obtained solution was added to a 50 vol% methanol aqueous solution. Thereby, polyimide P subjected to reprecipitation treatment was obtained.

Next, the obtained polyimide P was dissolved in N-methyl-2-pyrrolidone to prepare a coating solution. A leveling agent (Surflon S-243 (fluorosurfactant) manufactured by AGC Seimi Chemical Co., Ltd.) was added to the coating solution. This coating solution was applied onto a release liner (TM-0 manufactured by Nipper Co., Ltd.) to obtain a coating film. A separation functional layer was prepared by drying this coating film at 130 to 150° C. for 30 minutes. The release liner (TM-0) used in Reference Example 1 is a heavy release film that has relatively high adhesive strength with the separation functional layer.

Next, a double-sided adhesive tape (No. 5603 manufactured by Nitto Denko Corporation) was attached only to the peripheral edge of the separation functional layer. The separation functional layer and the porous support were bonded together via this double-sided adhesive tape. As the porous support, a nonwoven fabric (manufactured by Awa Paper Industries Co., Ltd.) whose surface on the separation functional layer side (the surface in contact with the double-sided adhesive tape) was coated with polysulfone (PSF) was used. The separation membrane of Reference Example 1 (separation membrane for measurement) was obtained by removing the release liner from the obtained laminate. In addition, in the separation membrane, the double-sided adhesive tape was placed at a position where it would not interfere with the fluid that had passed through the separation functional layer when conducting a test to measure the permeation rate T ₀ described later.

[Transmission rate T ₀ ]
Regarding the separation membrane of Reference Example 1, the carbon dioxide permeation rate T ₀ was measured by the following method. First, a separation membrane was set in a metal cell and sealed with an O-ring to prevent leakage. Next, the mixed gas was injected into the metal cell so that the mixed gas came into contact with the main surface of the separation membrane on the separation functional layer side. The gas mixture consisted essentially of carbon dioxide and nitrogen. The concentration of carbon dioxide in the gas mixture was 50 vol% under standard conditions. The mixed gas injected into the metal cell had a temperature of 30° C. and a pressure of 0.1 MPa. Next, the pressure in the space within the metal cell adjacent to the main surface of the separation membrane on the porous support side was reduced using a vacuum pump. At this time, the pressure in this space was reduced so that the pressure in the space was 0.1 MPa lower than the atmospheric pressure in the measurement environment. This resulted in a permeate fluid. The permeation rate T ₀ of carbon dioxide passing through the separation membrane was determined based on the composition of the obtained permeate fluid, the weight of the permeate fluid, etc.

(Example 1)
First, a separation functional layer was produced on a release liner by the same method as in Reference Example 1. Next, a double-sided tape (No. 5620A manufactured by Nitto Denko Corporation) was bonded onto the separation functional layer so that the main body portion was arranged in a striped pattern in a plan view. The adhesive part of the double-sided tape was made of an acrylic adhesive. An intermediate layer was formed by laminating a double-sided tape onto the separation functional layer. This intermediate layer had a space that could contact both the separation functional layer and the porous support. When the intermediate layer was viewed in plan, the area ratio R (aperture ratio) of the area where the space existed among the surfaces of the intermediate layer was 80%. The thickness of the intermediate layer was 200 μm.

Next, the separation functional layer and the porous support used in Reference Example 1 were bonded together via the intermediate layer. The separation membrane of Example 1 was obtained by removing the release liner from the obtained laminate.

(Examples 2-3)
Separation membranes of Examples 2 and 3 were obtained in the same manner as in Example 1, except that the intermediate layer was prepared so that the aperture ratio would have the value shown in Table 1.

(Comparative example 1)
A separation membrane of Comparative Example 1 was obtained in the same manner as in Example 1, except that the double-sided tape was placed on the entire surface of the separation functional layer. In the separation membrane of Comparative Example 1, the intermediate layer had no space.

(Example 4)
First, a separation functional layer was produced on a release liner by the same method as in Reference Example 1. Next, a coating liquid (silicone adhesive (KR3700, manufactured by Shin-Etsu Chemical Co., Ltd.)) was applied onto the separation functional layer so that the main body portions were arranged in stripes in a plan view. Next, the coating liquid was dried under heating conditions to form a main body, thereby obtaining an intermediate layer. This intermediate layer had a space that could contact both the separation functional layer and the porous support. When the intermediate layer was viewed in plan, the area ratio R (aperture ratio) of the area where the space existed among the surfaces of the intermediate layer was 80%. The thickness of the intermediate layer was 200 μm.

Next, the separation functional layer and the porous support used in Reference Example 1 were bonded together via the intermediate layer. The separation membrane of Example 4 was obtained by removing the release liner from the obtained laminate.

(Examples 5-6)
Separation membranes of Examples 5 and 6 were obtained in the same manner as in Example 4, except that the intermediate layer was prepared so that the aperture ratio had the value shown in Table 1.

(Comparative example 2)
A separation membrane of Comparative Example 2 was obtained in the same manner as in Example 4, except that the coating liquid was uniformly applied onto the separation functional layer. In the separation membrane of Comparative Example 2, the intermediate layer had no space.

(Example 7)
First, a separation functional layer was produced on a release liner by the same method as in Reference Example 1. Next, a coating liquid (silicone adhesive (KR3700, manufactured by Shin-Etsu Chemical Co., Ltd.)) was applied onto the separation functional layer so that the main body portion was arranged in dots in a plan view. Next, the coating liquid was dried under heating conditions to form a main body, thereby obtaining an intermediate layer. This intermediate layer had a space that could contact both the separation functional layer and the porous support. When the intermediate layer was viewed in plan, the area ratio R (aperture ratio) of the area where the space existed among the surfaces of the intermediate layer was 80%. The thickness of the intermediate layer was 200 μm.

Next, the separation functional layer and the porous support used in Reference Example 1 were bonded together via the intermediate layer. The separation membrane of Example 7 was obtained by removing the release liner from the obtained laminate.

(Examples 8-9)
Separation membranes of Examples 8 and 9 were obtained in the same manner as in Example 7, except that the intermediate layer was prepared so that the aperture ratio was as shown in Table 1.

(Examples 10 to 12)
Separation membranes of Examples 10 to 12 were obtained in the same manner as in Example 4, except that the intermediate layer was prepared so that the aperture ratio and thickness had the values shown in Table 2.

(Comparative example 3)
A separation membrane of Comparative Example 3 was obtained by the same method as Comparative Example 2, except that the intermediate layer was prepared so that the thickness had the value shown in Table 2.

(Examples 13 to 15)
As a double-sided tape, No. 1 manufactured by Nitto Denko Corporation is used. Separation membranes of Examples 13 to 15 were obtained in the same manner as in Example 1, except that 5601 was used and the intermediate layer was prepared so that the aperture ratio was as shown in Table 2. The adhesive part of the double-sided tape was made of an acrylic adhesive. The thickness of the intermediate layer formed by laminating the double-sided tape onto the separation functional layer was 10 μm.

(Comparative example 4)
A separation membrane of Comparative Example 4 was obtained in the same manner as in Example 13, except that the double-sided tape was placed on the entire surface of the separation functional layer. In the separation membrane of Comparative Example 4, the intermediate layer had no space.

(Examples 16 to 19)
First, MRF38 manufactured by Mitsubishi Chemical Corporation was prepared as a release liner. This release liner is a light release film that has relatively low adhesive strength with the separation functional layer. Next, the surface of this release liner was subjected to corona treatment under conditions of a discharge amount of 0.33 kW·min/m ² or more. Examples 16 to 19 were prepared by the same method as Example 4, except that the above release liner after corona treatment was used, and the intermediate layer was prepared so that the aperture ratio and thickness were as shown in Table 3. A separation membrane was obtained.

(Comparative example 5)
A separation membrane of Comparative Example 5 was obtained in the same manner as in Example 16, except that the coating liquid was uniformly applied onto the separation functional layer. In the separation membrane of Comparative Example 5, the intermediate layer had no space.

(Example 20)
First, a corona-treated release liner was prepared by the method described above for Example 16. Next, a separation functional layer was produced on the release liner by the same method as in Reference Example 1 except that the above release liner was used.

Next, a (meth)acrylic adhesive (coating liquid) was prepared by the following method. First, 95 parts by weight of butyl acrylate, 5 parts by weight of 4-hydroxybutyl acrylate as a hydroxyl group-containing monomer, and 2 parts by weight of 4-hydroxybutyl acrylate as a polymerization initiator were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. , 0.2 parts by weight of 2'-azobisisobutyronitrile, and 300 parts by weight of ethyl acetate were charged, and nitrogen substitution was performed for 1 hour while stirring gently. Thereafter, an ethyl acetate solution (solid content concentration: 25 wt%) of a (meth)acrylic polymer was prepared by performing a polymerization reaction for 7 hours while keeping the flask internal temperature at 60°C. Next, 0.5 parts by weight of a trimethylolpropane adduct of tolylene diisocyanate (Coronate L) as a crosslinking agent and 1600 parts by weight of ethyl acetate as a diluent were added to the obtained solution, and the solid content was 5 wt%. ) An acrylic adhesive was produced.

Next, the above coating liquid was applied onto the separation functional layer using a screen printing plate so that main bodies arranged in stripes in plan view were formed. This coating liquid was heated and dried at 130° C. for 10 minutes to form a main body, thereby obtaining an intermediate layer. This intermediate layer had a space that could contact both the separation functional layer and the porous support. When the intermediate layer was viewed in plan, the area ratio R (aperture ratio) of the area where the space existed among the surfaces of the intermediate layer was 80%. The thickness of the intermediate layer was 3 μm.

Next, the separation functional layer and the porous support used in Reference Example 1 were bonded together via the intermediate layer. The separation membrane of Example 20 was obtained by removing the release liner from the obtained laminate.

(Examples 21-23)
Separation membranes of Examples 21 to 23 were obtained by the same method as Example 20, except that the intermediate layer was prepared so that the aperture ratio and thickness had the values shown in Table 3.

(Comparative example 6)
A separation membrane of Comparative Example 6 was obtained in the same manner as in Example 20, except that the coating liquid was uniformly applied onto the separation functional layer. In the separation membrane of Comparative Example 6, the intermediate layer had no space.

(Examples 24-25)
Separation membranes of Examples 24 and 25 were obtained in the same manner as in Examples 17 and 19, respectively, except that the release liner of Reference Example 1 was used.

(Comparative example 7)
A separation membrane of Comparative Example 7 was obtained in the same manner as in Example 24, except that the coating liquid was uniformly applied onto the separation functional layer. In the separation membrane of Comparative Example 7, the intermediate layer had no space.

(Examples 26-27)
Separation membranes of Examples 26 and 27 were obtained in the same manner as in Examples 21 and 23, respectively, except that the release liner of Reference Example 1 was used.

(Comparative example 8)
A separation membrane of Comparative Example 8 was obtained in the same manner as in Example 26, except that the coating liquid was uniformly applied onto the separation functional layer. In the separation membrane of Comparative Example 8, the intermediate layer had no space.

(Example 28)
First, a separation functional layer was produced on a release liner by the same method as in Reference Example 1. Next, a rubber adhesive (solid adhesive) was produced by the following method. First, 100 parts by weight of styrene-isoprene-styrene block copolymer (SIS) as a base polymer, 55 parts by weight of isoprene rubber as a liquid component, and 45 parts by weight of terpene resin (YS Resin PX-1150) as a tackifier were blended. The mixture was kneaded at 150° C. for 30 minutes using a Laboplast Mill. In this way, a rubber adhesive was produced.

Next, the solid adhesive was sprayed onto the separation functional layer using a hot melt applicator equipped with a spray coating nozzle. As a result, a fibrous main body was formed and an intermediate layer was obtained. This intermediate layer had a space that could contact both the separation functional layer and the porous support. When the intermediate layer was viewed in plan, the area ratio R (aperture ratio) of the region where a space existed among the surfaces of the intermediate layer was 73%. The thickness of the intermediate layer was 55 μm.

Next, the separation functional layer and the porous support used in Reference Example 1 were bonded together via the intermediate layer. The separation membrane of Example 28 was obtained by removing the release liner from the obtained laminate.

(Examples 29-30)
Separation membranes of Examples 29 and 30 were obtained in the same manner as in Example 28, except that the intermediate layer was prepared so that the aperture ratio had the value shown in Table 5.

(Comparative example 9)
A separation membrane of Comparative Example 9 was obtained in the same manner as in Example 28, except that the solid adhesive was uniformly applied on the separation functional layer. In the separation membrane of Comparative Example 9, the intermediate layer had no space.

(Examples 31-32)
Separation membranes of Examples 31 and 32 were obtained by the same method as Example 28, except that the intermediate layer was prepared so that the aperture ratio and thickness had the values shown in Table 5.

[Permeation rate ratio T/T ₀ ]
For each of the separation membranes of Examples and Comparative Examples, the permeation rate T of carbon dioxide passing through the separation membrane was determined by the same method as in Reference Example 1. Based on the obtained results, we determined that the permeation rate T (GPU) of carbon dioxide permeating through the separation membranes of Examples and Comparative Examples with respect to the permeation rate T ₀ (GPU) of carbon dioxide permeating through the measurement separation membrane of Reference Example 1. ) ratio T/T ₀ was calculated.

As can be seen from Tables 1 to 5, in the separation membrane of the example equipped with the intermediate layer having a space in contact with both the separation functional layer and the porous support, the permeation rate ratio T/ T ₀ was high, and the permeation rate T of the permeate fluid was improved. Furthermore, in all of the separation membranes of Examples, the release liner could be easily removed during their preparation. From this, it can be seen that in the separation membrane of the example, the separation functional layer and the porous support were bonded with sufficient strength via the intermediate layer.

The separation membrane of this embodiment is suitable for separating acidic gas from a mixed gas containing acidic gas. In particular, the separation membrane of this embodiment is suitable for separating carbon dioxide from off-gas of chemical plants or thermal power generation.

Claims

a separation functional layer;
a porous support supporting the separation functional layer;
an intermediate layer disposed between the separation functional layer and the porous support;
Equipped with
The intermediate layer is a separation membrane having a space in contact with both the separation functional layer and the porous support.
The separation membrane according to claim 1, wherein the intermediate layer has a main body portion that joins the separation functional layer and the porous support.
The separation membrane according to claim 2, wherein the main body has a stripe shape, a dot shape, a mesh shape, or a fibrous shape in plan view.
The separation membrane according to claim 2, wherein the main body portion includes an adhesive portion formed from an adhesive composition.
The separation membrane according to claim 4, wherein the adhesive composition contains at least one selected from the group consisting of a silicone polymer, a (meth)acrylic polymer, and a rubber polymer.
The separation membrane according to any one of claims 1 to 5, wherein when the intermediate layer is viewed in plan, the area of the region where the space exists accounts for 40% or more of the surface of the intermediate layer. .
The separation membrane according to claim 1, wherein the intermediate layer has a thickness of 0.1 μm or more.
The separation membrane according to claim 1, wherein the separation functional layer contains a polyimide resin.
The separation membrane according to claim 1, which is used to separate carbon dioxide from a mixed gas containing carbon dioxide and nitrogen.
A method for producing a separation membrane comprising a separation functional layer, a porous support supporting the separation functional layer, and an intermediate layer disposed between the separation functional layer and the porous support. There it is,
The manufacturing method includes:
A second laminate having the release liner, the separation functional layer, and the intermediate layer in this order is formed by forming the intermediate layer having a space on the first laminate having the release liner and the separation functional layer. to form a
bonding the intermediate layer of the second laminate to the porous support so that the space contacts both the separation functional layer and the porous support to form a third laminate;
removing the release liner from the third laminate;
A method for producing a separation membrane, including: