Cured product for gas permeable membranes, and gas permeable membrane

Abstract

To provide: a cured product for gas permeable membranes that secures a sufficient CO2 gas permeability coefficient and has a high separation factor (CO2 / N2); and a gas permeable membrane.SOLUTION: A cured product for gas permeable membranes comprises a constitutional unit derived from a compound (A), which has a structure represented by the formula (1) defined by -(CH2-CH2-O)n- (where n is an integer equal to or greater than 2) and has three or more (meth)acryloyl groups as terminal groups. A gas permeable membrane comprises the cured product for gas permeable membranes.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a cured material for a carbon dioxide gas (hereinafter, CO2) permeable membrane and a gas permeable membrane. [Background technology]

[0002] One technology that aims to reduce CO2 emissions into the atmosphere to zero is known as Carbon dioxide Capture, Utilization and Storage (CCUS), which involves separating and capturing CO2 from gases in the atmosphere and storing it underground or converting it into chemical products or fuel for use.

[0003] One of the issues with CO2 capture technology is that it can be costly depending on the CO2 concentration in the gas species being captured. In recent years, CO2 capture using membrane separation has been attracting attention as a technology that can be operated at low cost because it uses pressure difference as the driving force and requires small equipment size. In CO2 capture by membrane separation, there is a trade-off between the CO2 gas permeability coefficient and separation coefficient (CO2 / N2) of the material that composes the gas permeable membrane used. Therefore, the materials that can be used for gas permeable membranes that selectively capture CO2 are limited. Polyethylene oxide (PEO) is known as a material that has excellent affinity for CO2 and a high separation coefficient (CO2 / N2). However, PEO cannot be used as a gas permeable membrane because it crystallizes and its CO2 gas permeability coefficient drops significantly.

[0004] Materials capable of suppressing the decrease in CO2 gas permeability coefficient due to crystallization include cured products using ethylene oxide (EO)-modified bifunctional acrylate monomers. Non-Patent Document 1 discloses a cured product using a bifunctional acrylate monomer with an EO modification number (EO addition mole number) of 14, and a membrane composed of the cured product. Non-Patent Document 2 discloses a cured product using a bifunctional acrylate monomer with an EO modification number (EO addition mole number) of 15, and a membrane composed of the cured product. However, although the membranes described in Non-Patent Documents 1 and 2 have a sufficiently high CO2 gas permeability coefficient, they have a low separation coefficient (CO2 / N2). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Kusuma et al., Journal of Membrane Science, 327, 2009, 195-207. [Non-Patent Document 2] Ricards et al., Chemical Engineering Science, 64, 2009, 4707-4718. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a cured material for a gas-permeable membrane and a gas-permeable membrane that have a high separation coefficient (CO2 / N2) while ensuring a sufficient CO2 gas permeability coefficient. [Means for solving the problem]

[0007] As a result of extensive research, the inventors have discovered that when a cured product is used that uses a tri- or higher functional (meth)acryloyl monomer with an EO modification number of 2 or more, a gas permeable membrane can be obtained that has a high separation coefficient (CO2 / N2) and can efficiently separate CO2 and N2 while maintaining a sufficient CO2 gas permeability coefficient, and have thus completed the present invention.

[0008] That is, the present invention includes the following configurations. [1] A cured material for a gas-permeable membrane, comprising a structural unit derived from a compound (A) having a structure represented by the following formula (1) and having three or more (meth)acryloyl groups as terminal groups: -(CH2-CH2-O) n - (1) (In the above formula (1), n ​​is an integer of 2 or more.) [2] The cured material for a gas-permeable membrane according to [1], wherein the compound (A) has a group represented by the following formula (2):

[0009] [ka]

[0010] (However, R in the above formula (2) 1 is a hydrogen atom or a methyl group. n is an integer of 2 or more. -* represents a bond. [3] The cured material for a gas-permeable membrane according to [1] or [2], which contains a structural unit derived from a compound represented by the following formula (3):

[0011] [ka]

[0012] (In the formula (3), n1 to n3 each independently represent an integer of 2 or more.) [4] The cured material for a gas-permeable membrane according to any one of [1] to [3], which contains a structural unit derived from a compound represented by the following formula (4):

[0013] [ka]

[0014] (In the formula (4), n4 to n9 each independently represent an integer of 2 or more.) [5] A gas-permeable membrane comprising the cured product for gas-permeable membrane according to any one of [1] to [4]. Effect of the Invention

[0015] According to the present invention, there are provided a cured material for a gas permeable membrane and a gas permeable membrane which have a high separation coefficient (CO2 / N2) while ensuring a sufficient CO2 gas permeability coefficient. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Cured material for gas permeable membrane] The cured product for a gas-permeable membrane according to the embodiment has a structure represented by the following formula (1) (hereinafter also referred to as "structure (1)") and contains a constituent unit derived from a compound (A) having three or more (meth)acryloyl groups as terminal groups. -(CH2-CH2-O) n - (1) In the above formula (1), n ​​is an integer of 2 or more.

[0017] Compound (A) is a compound having structure (1) and having three or more (meth)acryloyl groups as terminal groups. That is, compound (A) is a polyfunctional (meth)acrylic monomer having an EO modification number (EO addition mole number) of 2 or more and a functionality of 3 or more.

[0018] In formula (1), n, i.e., the EO modification number (the number of moles of EO added), is 2 or more, preferably 5 or more, and more preferably 8 or more. When n is equal to or more than the lower limit, a gas permeable membrane with a high separation factor (CO2 / N2) is easily obtained. n is preferably 20 or less, and more preferably 15 or less. The preferable lower and upper limits of n can be arbitrarily combined, and for example, 2 to 20 is preferable. Furthermore, when compound (A) contains a plurality of structures (1), the upper limit of the total number of n is preferably not more than 100, more preferably not more than 90, even more preferably not more than 80, and particularly preferably not more than 65. When the total number of n is not more than the upper limit, the crosslink density falls within an appropriate value, and the film is easily self-supporting.

[0019] The number of (meth)acryloyl groups that the compound (A) has as an end group is 3 or more, preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more. If the number of (meth)acryloyl groups is equal to or more than the lower limit, the crosslink density increases, and the strength of the gas permeable membrane increases. In addition, a gas permeable membrane with a high separation coefficient (CO2 / N2) is easily obtained. The number of (meth)acryloyl groups that the compound (A) has as an end group is preferably 10 or less, more preferably 9 or less, even more preferably 8 or less, and particularly preferably 6 or less. If the number of (meth)acryloyl groups is equal to or less than the upper limit, the crosslink density becomes appropriate, and the membrane is easily molded. The preferable lower limit and upper limit of the number of (meth)acryloyl groups can be arbitrarily combined, and for example, 3 to 6 is preferable. It is to be noted that the number of (meth)acryloyl groups, which are the terminal groups of the compound (A), and the number of EO modifications (the number of moles of EO added) should be considered together rather than being selected independently. The above-mentioned preferred lower and upper limits of the number of (meth)acryloyl groups and the number of EO modifications (the number of moles of EO added) can be arbitrarily combined. For example, it is preferable that the number of (meth)acryloyl groups is 3 or more and the number of EO modifications (the number of moles of EO added) is 2 or more, more preferably that the number of (meth)acryloyl groups is 4 or more and the number of EO modifications (the number of moles of EO added) is 5 or more, and even more preferably that the number of (meth)acryloyl groups is 5 or more and the number of EO modifications (the number of moles of EO added) is 8 or more.

[0020] As compound (A), a compound having a group represented by the following formula (2) (hereinafter also referred to as "group (2)") is preferred, since it is easy to obtain a gas-permeable membrane having a high CO2 gas permeability coefficient and separation coefficient (CO2 / N2).

[0021] [ka]

[0022] However, R in the above formula (2) 1 is a hydrogen atom or a methyl group. -* indicates a bond. The structure to which -* is bonded is not particularly limited, but if it becomes an alcohol group, the free volume decreases, so a hydrocarbon group such as a methyl group or an ethyl group is preferable.

[0023] The group (2) is a group containing a (meth)acryloyl group as a terminal group and the structure (1). Since a gas-permeable membrane having a high CO2 gas permeability coefficient and a high separation coefficient (CO2 / N2) is easily obtained, it is preferable that the compound (A) has all of the (meth)acryloyl groups as terminal groups as part of the group (2).

[0024] The number of groups (2) in the compound (A) is preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, and particularly preferably 6 or more. If the number of groups (2) is equal to or more than the lower limit, a gas permeable membrane with a high separation coefficient (CO2 / N2) is easily obtained. The number of groups (2) in the compound (A) is preferably 10 or less, more preferably 9 or less, even more preferably 8 or less, and particularly preferably 6 or less. If the number of groups (2) is equal to or less than the upper limit, the crosslinking density is appropriate and the membrane is easily molded. The preferred lower and upper limits of the number of groups (2) can be arbitrarily combined, and for example, 3 to 6 is preferred.

[0025] The compound (A) is preferably a compound in which three or more hydrogen atoms of a hydrocarbon which may have an etheric oxygen atom are substituted with a group (2). The hydrocarbon which may have an etheric oxygen atom may be linear, branched, or cyclic. The number of carbon atoms in the hydrocarbon which may have an etheric oxygen atom is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more, and is preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less.

[0026] Examples of the compound (A) include glycerin polyethoxy tri(meth)acrylate, dipentaerythritol polyethoxy hexa(meth)acrylate, a compound represented by the following formula (3), and a compound represented by the following formula (4). The cured product for gas-permeable membrane according to the embodiment preferably contains, as a structural unit derived from compound (A), either or both of a structural unit derived from a compound represented by formula (3) and a structural unit derived from a compound represented by formula (4).More preferably, as a structural unit derived from compound (A), either or both of a structural unit derived from a compound represented by formula (3) and a structural unit derived from a compound represented by formula (4).

[0027] [ka]

[0028] In the formula (3), n1 to n3 each independently represents an integer of 2 or more. The preferred range for each of n1 to n3 is the same as the preferred range for n. The preferred upper limit for the total number of n1 to n3 is the same as the preferred upper limit for the total number of n.

[0029] [ka]

[0030] In the formula (4), n4 to n9 each independently represents an integer of 2 or more. The preferred range for each of n4 to n9 is the same as the preferred range for n. The preferred upper limit for the total number of n4 to n9 is the same as the preferred upper limit for the total number of n.

[0031] The method for producing compound (A) is not particularly limited. For example, compound (A) can be produced by reacting a polyhydric alcohol having three or more functional groups with ethylene oxide (EO) to obtain a reaction product, and then reacting the reaction product with (meth)acrylic acid. Examples of the polyhydric alcohol having three or more functional groups include polyglycerols such as triglycerin and tetraglycerin, trimethylolpropane, and sorbitol. As the polyhydric alcohol having three or more functional groups, one type may be used alone, or two or more types may be used in combination.

[0032] The cured product for a gas-permeable membrane according to the embodiment may contain, in addition to the constituent units derived from the compound (A), constituent units derived from other (meth)acrylic monomers other than the compound (A). Examples of (meth)acrylic monomers other than the compound (A) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, isoamyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, acrylate, 2-ethoxyethyl (meth)acrylate, ethoxy-diethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, 2-ethylhexyl diethoxy (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, carbitol (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxy diethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, hydrogenated dicyclopentadiene (meth)acrylate, acryloylmorpholine, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-Nonanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 2-n-butyl-2-ethyl-3-propanediol di(meth)acrylate, tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, trimethylolpropane polypropoxy tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylol Examples of the acrylates include arylmethane tetra(meth)acrylate, glycerin polypropoxy tri(meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A polypropoxy di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol polypropoxy hexa(meth)acrylate. As the other (meth)acrylic monomer, one type may be used alone, or two or more types may be used in combination.

[0033] The content of the structural unit derived from the compound (A) in the cured product for gas permeable membrane according to the embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more, based on the total amount of the structural units of the cured product for gas permeable membrane. If the content of the structural unit derived from the compound (A) is equal to or more than the lower limit, a gas permeable membrane with a high separation factor (CO2 / N2) is easily obtained. The upper limit of the content of the structural unit derived from the compound (A) is not particularly limited, and may be 100% by mass.

[0034] The cured product for a gas-permeable film according to the embodiment can be obtained, for example, by curing a composition for a gas-permeable film containing compound (A), an optional (meth)acrylic monomer other than compound (A), and a photoinitiator with active energy rays. Examples of the active energy rays include electron beams, X-rays, ultraviolet rays, and visible light in the low wavelength region, with ultraviolet rays being preferred.

[0035] Examples of the photoinitiator include ketones such as 1-hydroxycyclohexyl phenyl ketone (HCPK), benzophenone, etc. As the photoinitiator, one type may be used alone, or two or more types may be used in combination. The content of the photoinitiator in the composition for gas-permeable membrane is preferably 0.01 parts by mass or more and 1 part by mass or less, more preferably 0.05 parts by mass or more and 0.5 parts by mass or less, and even more preferably 0.1 parts by mass or more and 0.3 parts by mass or less, relative to 100 parts by mass of the monomer including compound (A).

[0036] [Gas permeable membrane] The gas-permeable membrane according to the embodiment includes the cured material for a gas-permeable membrane of the present invention described above. The gas-permeable membrane according to the embodiment may be a membrane consisting of a single non-porous layer formed from the cured material for a gas-permeable membrane of the present invention, or may be a membrane including a porous support and a non-porous layer formed on the porous support from the cured material for a gas-permeable membrane of the present invention.

[0037] The form of the gas permeable membrane is not particularly limited, and may be a flat membrane or a hollow fiber membrane. For example, when the gas permeable membrane is a flat membrane, it may be a flat membrane of a two-layer structure having a porous support and a non-porous layer, or a flat membrane of a three-layer structure having a porous support on both sides of a non-porous layer. For example, when the gas permeable membrane is a hollow fiber membrane, it may be a two-layer hollow fiber membrane having a non-porous layer on the inside or outside of a hollow porous support, or it may be a three-layer hollow fiber membrane having a porous support on the inside and outside of a hollow non-porous layer.

[0038] The thickness of the non-porous layer is preferably 0.1 μm or more, more preferably 0.5 μm or more. If the thickness of the non-porous layer is equal to or more than the lower limit, CO2 can be efficiently and selectively separated and captured. The thickness of the non-porous layer is preferably 10 μm or less, more preferably 1 μm or less. If the thickness of the non-porous layer is equal to or less than the upper limit, the permeation resistance can be reduced, and CO2 can be efficiently captured.

[0039] The porous support is not particularly limited as long as it has sufficient mechanical strength to reinforce the non-porous layer and can be integrated with the non-porous layer. Examples of materials constituting the porous support include polyolefin polymers such as polyethylene, polypropylene, poly-3-methylbutene-1, poly-4-methylpentene-1, etc., fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, etc., and hydrophobic polymers such as polystyrene, polyether ketone, etc. The materials constituting the porous support may be used alone or in combination of two or more.

[0040] The cured product for a gas-permeable membrane and the gas-permeable membrane of the present invention are not limited to the above-mentioned configurations. The components in the above-mentioned embodiment may be appropriately replaced with well-known components without departing from the spirit of the present invention, and the above-mentioned modified examples may be appropriately combined. EXAMPLES

[0041] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0042] [Abbreviation] The abbreviations for the raw materials used in this example are as follows. (Compound (A)) A-1: MIRAMER M3150 (manufactured by Miwon, number of acryloyl groups: 3, compound represented by formula (3), n1 = n2 = n3 = 5) A-2: Syntech SA-TE60 (manufactured by Sakamoto Pharmaceutical Co., Ltd., number of acryloyl groups: 6, compound represented by formula (4), n4 = n5 = n6 = n7 = n8 = n9 = 10) (Bifunctional acrylate (for comparison)) PEGDA: Poly(ethylene glycol) diacrylate (EO modification number: 14) BPA-EDA: Bisphenol A ethoxylate diacrylate (EO modification number: 30) (Photoinitiator) HCPK: 1-hydroxycyclohexyl phenyl ketone

[0043] [Measurement of gas permeability coefficient P (Barrer) and separation factor] (1) Preparation of gas-permeable membrane The composition for gas permeable membrane was applied onto a polyester film (hereinafter referred to as "PET film") (Cosmo Sunshine, manufactured by Toyobo Co., Ltd., thickness: 188 μm) with a spacer attached, and a PET film was further placed on top of it, and the film was spread so that the thickness of the film after curing between the two films would be about 200 μm. Next, a high-pressure mercury lamp (commercially available) was used to irradiate the film with ultraviolet light of 340 to 380 nm in wavelength in the air at an integrated light intensity of 500 mJ / cm. 2 The composition for a gas-permeable film was cured to form a gas-permeable film.

[0044] (2)Measurement method The resulting laminate including the gas-permeable membrane was cut into a circular shape with a diameter of 35 mm, and the PET film was peeled off to collect a measurement sample consisting of the gas-permeable membrane. Using a gas permeability measuring device (K-315N-01, manufactured by Tsukubarika Seiki Co., Ltd.), the CO2 gas permeability coefficient and N2 gas permeability coefficient of the obtained measurement sample were measured under the conditions of a temperature of 25.5°C and a measurement pressure of 102 kPa by the pressure method using nitrogen and carbon dioxide as the supply gases. The gas permeability coefficient P (Barrer) was calculated from the following formula (5). In addition, the separation factor (CO2 / N2) was calculated by dividing the CO2 gas permeability coefficient by the N2 gas permeability coefficient.

[0045]

number

[0046] The symbols in the formula (5) have the following meanings. V: Low pressure tank volume (cm 3 ) A: Permeable area (cm) of the measurement sample (gas permeable membrane) 2 ) T: Temperature in the cell (K) l: Thickness of the measurement sample (gas permeable membrane) (cm) P H : High pressure tank pressure (cmHg) P L : Low pressure tank pressure (cmHg)

[0047] [Example 1] A liquid composition for a gas-permeable film was prepared by mixing 100 parts by mass of compound (A-2) as compound (A) and 0.1 parts by mass of HCPK as a photoinitiator. The gas-permeable membrane prepared using the composition for gas-permeable membrane had a CO2 gas permeability coefficient of 80.0 (Barrer).

[0048] [Example 2] A composition for a gas-permeable film was prepared in the same manner as in Example 1, except that the compound (A-1) was used instead of the compound (A-2). The gas-permeable membrane prepared using the composition for a gas-permeable membrane had a CO2 gas permeability coefficient of 28.0 (Barrer).

[0049] [Comparative Example 1] A composition for a gas-permeable film was prepared in the same manner as in Example 1, except that PEGDA was used instead of the compound (A-2).

[0050] [Comparative Example 2] A composition for a gas-permeable film was prepared in the same manner as in Example 1, except that BPA-EDA was used instead of the compound (A-2).

[0051] For the gas-permeable membrane compositions of the Examples and Comparative Examples, gas-permeable membranes were prepared and the separation coefficients (CO2 / N2) were measured, and the results are shown in Table 1. In addition, the "EO modification number" in Table 1 means the total number of EO modifications in the compound.

[0052] [Table 1]

[0053] As shown in Table 1, the gas-permeable membranes of Examples 1 and 2, which used a cured material for a gas-permeable membrane containing a structural unit derived from compound (A), had a higher separation factor (CO2 / N2) than the gas-permeable membranes of Comparative Examples 1 and 2, which used a cured material containing a structural unit derived from an EO-modified bifunctional acrylate monomer.

Claims

1. A cured material for a gas-permeable membrane, comprising a structural unit derived from a compound (A) having a structure represented by the following formula (1) and having three or more (meth)acryloyl groups as terminal groups: -(CH ２ -CH ２ -O) ｎ - ・・・(1) (In the above formula (1), n ​​is an integer of 2 or more.)

2. The cured material for a gas-permeable membrane according to claim 1 , wherein the compound (A) has a group represented by the following formula (2): 【Chemistry 1】 (However, R in the above formula (2) １ is a hydrogen atom or a methyl group. n is an integer of 2 or more. -* indicates a bond.

3. 2. The cured material for a gas-permeable membrane according to claim 1, comprising a structural unit derived from a compound represented by the following formula (3): 【Chemistry 2】 (In the formula (3), n1 to n3 are each independently an integer of 2 or more.)

4. 2. The cured material for a gas-permeable membrane according to claim 1, comprising a structural unit derived from a compound represented by the following formula (4): 【Chemistry 3】 (In the formula (4), n4 to n9 are each independently an integer of 2 or more.)

5. A gas-permeable membrane comprising the cured material for gas-permeable membrane according to any one of claims 1 to 4.

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