Polymer materials and methods for producing the same, gas absorption materials, gas recovery devices

Abstract

To provide a gas absorbent with high reversible CO2 absorption capacity. [Solution] A gas absorbent material that is partly composed of a gas absorbent material containing a polymer material having the function of absorbing and releasing acidic gases. It has a structure in which powder of the gas absorbent material is filled inside a honeycomb-shaped structure, a laminated structure of a sheet of the gas absorbent material and a nonwoven fabric or mesh, a structure in which the gas absorbent material is filled inside a filter, or a structure in which a film of the gas absorbent material is supported on a carrier, or a self-supporting film, fiber or pellet formed by kneading the gas absorbent material with a hard material.

Description

[Technical Field]

[0001] This invention relates to polymer materials and methods for producing the same. [Background technology]

[0002] In recent years, environmental pollution caused by carbon dioxide emissions from facilities such as thermal power plants, steel mills, and cement factories, as well as harmful gases like hydrogen sulfide, has become a serious problem. To prevent the effects of these gases, research and development is underway to separate and recover them. Among these efforts, there is research on gas absorbents and gas separators that utilize the reversible gas absorption capacity of polymer particles synthesized by polymerizing monomers with amino groups and monomers with hydrophobic groups. For example, Patent Documents 1 and 2 describe the production of polymer particles by adding 2,2'-azobis(2-methylpropionamidine) dihydrochloride as an initiator to a monomer mixture (total monomer concentration 0.312 mol / L) prepared by dissolving 55 mol% N-(dimethylaminopropyl)methacrylamide, 43 mol% N-tert-butylacrylamide, and 2 mol% N,N'-methylenebisacrylamide in water, reacting the mixture, and freeze-drying the mixture. The produced polymer particles can be formed into a film by methods such as spray-coating the aqueous dispersion onto a porous material, and the resulting film is shown to be useful as a reversible gas absorbent material that absorbs carbon dioxide and then releases carbon dioxide upon heating. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2016 / 024633 [Patent Document 2] International Publication No. 2017 / 146231 [Overview of the project] [Problems that the invention aims to solve]

[0004] The inventors of this invention conducted research with the aim of developing a polymer material with low water content while possessing reversible gas absorption performance, and at the same time providing a method for efficiently producing this polymer material. [Means for solving the problem]

[0005] Specifically, the following solutions are provided.

[0006] [1] Amine-containing polymer material comprising a polymer of a monomer mixture consisting of a monofunctional monomer and a polyfunctional monomer in an amount of more than 10 mol% and less than or equal to 30 mol%. [2] The polymer material according to [1], wherein the monofunctional monomer has an amino group. [3] The polymer material according to [1] or [2], wherein the polyfunctional monomer is N,N'-alkylenebis(meth)acrylamide. [4] The polymer material according to [1] or [2], wherein the polyfunctional monomer has an amino group. [5] The polymer material according to [1] or [2], wherein the polyfunctional monomer has a plurality of amino groups. [6] The polymer material according to any one of [1] to [5], wherein the polymer is polymerized using 2,2'-azobis(2-methylpropionitrile) as an initiator. [7] The polymer material according to any one of [1] to [6], wherein the polymer is polymerized in the presence of a surfactant. [8] A polymer material according to any one of items [1] to [7], comprising a surfactant. [9] The polymer material according to [7] or [8], wherein the surfactant is cetyltrimethylammonium bromide.

[10] A polymer material described in any one of items [1] to [9], which is a pulverized product.

[11] A polymer material described in any one of items [1] to

[10] , which is a filtrate.

[12] A polymer material described in any one of items [1] to

[11] , which is a dry product.

[13] The polymer material according to any one of [1] to

[12] , wherein the polymer is a polymer obtained by polymerizing water and alcohol as solvents.

[14] The polymer material according to any one of [1] to

[13] , wherein the monomer mixture comprises a monomer having a hydrophobic group.

[15] A polymer material for gas absorption, as described in any one of items [1] to

[14] .

[16] A polymer material for absorbing carbon dioxide gas, as described in any one of items [1] to

[15] .

[17] A polymer material according to any one of [1] to

[16] that can reversibly absorb carbon dioxide gas.

[18] A polymer material according to any one of [1] to

[17] , wherein the water content of the polymer is 3 grams or less when 1 gram of dry polymer is immersed in water overnight at 30°C.

[19] A polymer synthesis step comprising polymerizing monomers in a reaction mixture containing monofunctional monomers, polyfunctional monomers, a solvent and an initiator, The process includes an amine impregnation step in which the polymer is impregnated with a treatment solution containing an amine, The total monomer concentration of the reaction mixture is 0.7 mol / L or more. The proportion of the polyfunctional monomer among the monomers contained in the reaction mixture is 10 to 30 mol%, A method for producing a polymer material, wherein the amine impregnation step may not be performed if the monofunctional monomer has an amino group.

[20] The method for producing a polymer material according to

[19] , wherein the monofunctional monomer has an amino group, and the amine impregnation step is performed.

[21] The method for producing a polymer material according to

[19] , wherein the monofunctional monomer has an amino group and the amine impregnation step is not performed.

[22] A method for producing a polymer material according to any one of

[19] to

[21] , wherein the polyfunctional monomer is N,N'-alkylenebis(meth)acrylamide.

[23] The method for producing a polymer material according to any one of

[19] to

[21] , wherein the polyfunctional monomer has an amino group.

[24] The method for producing a polymer material according to any one of

[19] to

[21] , wherein the polyfunctional monomer has a plurality of amino groups.

[25] The method for producing a polymer material according to any one of

[19] to

[24] , wherein the initiator is 2,2'-azobis(2-methylpropionitrile).

[26] The method for producing a polymer material according to any one of

[19] to

[25] , wherein the reaction mixture contains a surfactant.

[27] The method for producing a polymer material according to

[26] , wherein the surfactant is cetyltrimethylammonium bromide.

[28] The method for producing a polymer material according to any one of

[19] to

[27] , wherein the polymer obtained in the polymer synthesis step is pulverized. <​​​​​​​​​​​​​​

[36] A method for producing a polymer material for gas absorbent materials, according to any one of

[19] to

[35] .

[37] A method for producing a polymer material for carbon dioxide gas absorption, according to any one of

[19] to

[36] .

[38] A method for producing a polymer material that can reversibly absorb carbon dioxide gas, according to any one of

[19] to

[36] .

[39] A method for producing a polymer material, wherein the water content of the polymer is 3 grams or less when 1 gram of dry polymer is immersed in water at 30°C overnight, as described in

[38] . A polymer material manufactured by the manufacturing method described in any one of the following items:

[40]

[19] to

[39] .

[41] A gas-absorbing material containing a polymer material as described in any one of items [1] to

[18] and

[40] .

[42] The gas-absorbing material according to

[41] further comprising a thermoplastic resin.

[43] The gas absorbing material according to

[42] , wherein the thermoplastic resin is polyethylene.

[44] A gas-absorbing material according to any one of the items

[41] to

[43] , further comprising a filler.

[45] The gas absorbing material according to

[44] , wherein the filler has gas adsorption capacity.

[46] The gas-absorbing material according to

[44] or

[45] , wherein the filler is in powder form.

[47] The gas absorbing material according to any one of

[44] to

[46] , wherein the primary particles of the filler have a particle size of 1000 nm or less.

[48] ​​The gas absorbing material according to any one of

[44] to

[47] , wherein the water contact angle of the fine particles is 70° or more.

[49] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is carbon black.

[50] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is water-repellent treated carbon black.

[51] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is fumed silica.

[52] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is fumed silica that has been treated to be water-repellent.

[53] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is a fluorinated resin powder.

[54] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is Teflon® powder.

[55] The gas absorbing material according to any one of

[44] to

[48] , wherein the filler is activated carbon or zeolite.

[56] A gas-absorbing material according to

[41] to

[55] , which is swollen with water.

[57] The gas absorbent material described in

[41] to

[56] , which has been hydrated with water vapor.

[58] The gas absorbent material described in

[57] , wherein carbon dioxide gas or bicarbonate ions are added during the addition of water. A gas absorption cartridge filled with any one of the gas absorption materials described in

[59]

[41] to

[58] . A gas supply device containing a gas-absorbing material as described in any one of items

[60] ,

[41] , to

[58] . A gas recovery device containing a gas-absorbing material as described in any one of the items

[61]

[41] to

[58] .

[62] The gas recovery device according to

[61] , wherein after absorbing gas with the gas-absorbing material, the gas is desorbed by raising the temperature of the gas-absorbing material.

[63] The gas recovery device according to

[61] , wherein the gas is absorbed and stored with the gas-absorbing material, and then the gas is desorbed by reducing the partial pressure of the gas.

[64] The gas recovery apparatus according to

[61] , wherein the gas is absorbed by the gas-absorbing material and then the gas is desorbed by passing water vapor through it.

[65] The gas recovery apparatus according to

[61] , wherein after absorbing gas with the gas-absorbing material, the gas is desorbed by flowing high-temperature water through it.

[66] A gas recovery device according to any one of

[61] to

[65] , wherein when the gas is absorbed by the gas-absorbing material, the rise in temperature of the gas-absorbing material due to the heat of the gas absorption reaction is suppressed by the evaporation of water from the gas-absorbing material.

[67] A gas recovery device according to any one of

[61] to

[66] , wherein when the gas is absorbed by the gas-absorbing material, the temperature of the gas-absorbing material is reduced by passing a dry gas through it.

[68] A gas recovery apparatus according to any one of items

[61] to

[67] , wherein the gas is an acidic gas.

[69] A gas recovery device according to any one of items

[61] to

[67] , wherein the gas is carbon dioxide gas.

[70] A gas recovery apparatus according to any one of items

[61] to

[67] , wherein the gas is water vapor. [Effects of the Invention]

[0007] According to the method for producing polymer materials of the present invention, it is possible to produce polymer materials with low water content while having reversible gas absorption performance, and the produced polymer materials can be effectively used as reversible gas absorption materials. A gas recovery device using the gas absorption material of the present invention can efficiently recover acidic gases such as carbon dioxide and water vapor. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing a first embodiment of the gas recovery device of the present invention. [Figure 2] This is a schematic diagram showing a second embodiment of the gas recovery device of the present invention. [Figure 3] This shows the particle size distribution of a mixture of various polymer pulverized materials and RY300 (polymer material containing fine particles). [Figure 4] This graph shows the amount of CO2 absorbed during the absorption process and the amount of CO2 released during the release process for polymer pulverized at a 7-rin (7mm) mill, polymer material containing fine particles including RY300 (sample 18), and polymer pulverized at a 7-rin mill (sample 19). [Figure 5]This graph shows the amount of CO2 absorbed during the absorption process for a polymer material containing amino groups and fine particles containing RY300, which was ground to a 7-rin (7mm) mill (sample 18), and a powdered material obtained by grinding a mixture of polymer powder ground to a 1.5-bu mill and RY300 in a bead mill (sample 20). [Modes for carrying out the invention]

[0009] The present invention will be described in detail below. The following descriptions of constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. In this specification, "(meth)acrylamide" means "acrylamide" and "methacrylamide," and "(meth)acrylate" means "acrylate" and "methacrylate."

[0010] <Polymer materials> The polymer material can be, for example, an amine-containing polymer material containing a polymer of a monomer mixture consisting of a monofunctional monomer and a polyfunctional monomer in an amount of more than 10 mol% and less than or equal to 30 mol%. The proportion of polyfunctional monomers in a monomer mixture can be greater than 10 mol% and 30 mol% or less, and can also be between 15 mol% and 30 mol%. Polymer materials can be polymerized, for example, under conditions where they are moderately crosslinked or do not swell excessively. Even after immersion in water, they have low water content while possessing a large amount of amines, enabling them to reversibly absorb acidic gases such as carbon dioxide and water vapor. Furthermore, it can reversibly absorb large amounts of acidic gases even under high humidity conditions. Even when used in high-humidity environments, it can be used for extended periods with a high packing density per unit volume without swelling due to excessive water absorption. Furthermore, it eliminates the need for extra energy to regulate the water temperature when releasing gases such as carbon dioxide through heating or other temperature control methods, without excessive water content. Polymer materials can be efficiently manufactured by the manufacturing methods described below.

[0011] <Method for manufacturing polymer materials> A method for producing a polymer material includes, for example, a polymer synthesis step of synthesizing a polymer by polymerizing monomers in a reaction mixture containing monofunctional monomers, polyfunctional monomers, a solvent, and an initiator, and an amine impregnation step of impregnating the polymer with a treatment solution containing an amine, wherein the total monomer concentration of the reaction mixture is 0.7 mol / L or higher, and the proportion of polyfunctional monomers among the monomers contained in the reaction mixture can be greater than 10 mol% and 30 mol% or less. However, if the monofunctional monomer has an amino group, the above amine impregnation step may be omitted. In the method for producing polymer materials, by setting the total monomer concentration and the proportion of polyfunctional monomers in the reaction mixture within the above range, polymer materials with low water content and high reversible gas absorption can be efficiently obtained. Furthermore, it is possible to synthesize a sufficient amount of polymer with a relatively small amount of solvent, thus preventing the need for large-scale manufacturing equipment. Furthermore, because the resulting polymer material has low swelling properties, it can be manufactured into products such as gas absorbers and gas separators with a sufficiently large volume packing ratio. The following sections will provide a detailed explanation of each step.

[0012] [1] Polymer synthesis process In this process, polymers are synthesized by polymerizing monomers in a reaction mixture containing monofunctional monomers, polyfunctional monomers, a solvent, and an initiator. The following describes the monomers, solvents, initiators, and surfactants used in the polymer synthesis process, as well as the conditions for the polymerization reaction and the post-treatment of the polymer.

[0013] [Monofunctional monomer] A "monofunctional monomer" is, for example, a monomer that has only one polymerizable group within its molecule. Examples of polymerizable groups include ethylenically unsaturated polymerizable groups such as vinyl groups, acryloyl groups, methacryloyl groups, and styrenyl groups. The reversible gas absorption capacity of the polymer produced is manifested, for example, by the reaction between an amino group and a gas component, or by the reaction between an amino group, a gas component, and water. The monofunctional monomer used here may or may not have an amino group. Furthermore, a combination of a monofunctional monomer without an amino group and a monofunctional monomer having an amino group may be used. Furthermore, if a monofunctional monomer having an amino group is used, the "amine impregnation step" described later may not be necessary. Examples of monofunctional monomers that do not have an amino group include acrylamide, methacrylamide, acrylic acid, acrylate, methacrylic acid, methacrylate, 2-acrylamide-2-methylpropanesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, N-alkylacrylamide, N-alkylmethacrylamide, alkyl acrylate, alkyl methacrylate, N,N-dialkylacrylamide, N-(hydroxyalkyl)acrylamide, (hydroxyalkyl)acrylate, N,N-dialkylmethacrylamide, N-(hydroxyalkyl)methacrylamide, (hydroxyalkyl)methacrylate, etc., and other substituted (meth)acrylamides can also be used. Specific examples of monofunctional monomers that do not have an amino group include N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dipropylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylmethacrylamide, and N,N-dipropylmethacrylamide. Here, the terminal propyl group may be an n-propyl group or an isopropyl group. These monomers that do not have an amino group may be used individually or in combination of two or more types. If a monofunctional monomer has an amino group, that amino group may be a primary amino group, a secondary amino group, or a tertiary amino group. The term "amino group" does not necessarily refer to the amino group that constitutes an amide structure (-CO-NR2: where R is a hydrogen atom or substituent). The amino group in a monofunctional monomer may also have its acid dissociation constant (pKa) designed to function as a conjugate acid. To increase the carbon dioxide absorption efficiency of the manufactured polymer, the acid dissociation constant (pKa) of the amino group in a carbon dioxide-absorbing environment can be made equal to or greater than the acid dissociation constant (pKa) of carbonic acid. Primary amino groups and some secondary amino groups form strong covalent bonds with carbon dioxide, which can prevent them from releasing the carbon dioxide they have absorbed. Therefore, when a monofunctional monomer has an amino group, it can be a secondary amino group or a tertiary amino group, and it can also be a secondary or tertiary amino group that has a hydroxyl group, amide group, or alkyl group nearby, or it can be a dialkylamino group such as a dimethylamino group. Furthermore, the amine may be a monofunctional monomer having a cyclic amine such as piperidine or piperazine, or a derivative thereof. If the acid dissociation constant of the amino group is too high, carbon dioxide may not be efficiently released during decontamination. Therefore, by copolymerizing monomers with amino groups with monomers having hydrophobic side chains, or by introducing a certain amount of polyfunctional monomers, it is possible to create a crowded environment around the amino groups within the gel. In monofunctional monomers, the amino group may be bonded to the main chain portion of the polymer, or to the side chain portion, or it may be bonded to the side chain portion. Furthermore, the number of amino groups in a monofunctional monomer is not particularly limited; it may be one or two or more. If a monomer has two or more amino groups, each amino group may be the same or different.

[0014] Examples of monomers having an amino group include N-(aminoalkyl)acrylamide, N-(aminoalkyl)methacrylamide, aminoalkyl acrylate, and aminoalkyl methacrylate. In these monomers, the amino group may be substituted with substituents such as alkyl groups. Specific examples of monomers having an amino group include N,N-dimethylaminopropyl methacrylamide, N,N-diethylaminopropyl methacrylamide, N,N-dimethylaminoethyl methacrylamide, N,N-diethylaminoethyl methacrylamide, N,N-dimethylaminopropyl methacrylate, N,N-diethylaminopropyl methacrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminopropyl acrylamide, N,N-diethylaminopropyl acrylamide, N,N-diethylaminoethyl acrylamide, 3-aminopropyl methacrylamide, 3-aminopropyl acrylamide, N,N-dimethylaminopropyl acrylate, N,N-diethylaminopropyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, 3-aminopropyl methacrylate, and 3-aminopropyl acrylate. Alternatively, these compounds may be salts of acidic substances, such as hydrochloride or bicarbonate. Alternatively, they may be acrylamide synthesized by condensing commercially available oligoamines or polyamines having primary or secondary amines with acrylic acid, methacrylic acid, or derivatives thereof. Furthermore, ethyleneimine, vinylamine, allylamine, allylamine hydrochloride, and the like can also be used as monomers having an amino group. These monofunctional monomers having amino groups may be used individually or in combination of two or more types.

[0015] [Polyfunctional monomers] A "polyfunctional monomer" is, for example, a monomer that has two or more polymerizable groups in its molecule. For specific examples of polymerizable groups, please refer to the section on [monofunctional monomers]. The number of polymerizable groups in a polyfunctional monomer is not particularly limited, but it can be 2 to 6, 2 to 5, 2 to 4, or 2. The multiple polymerizable groups in a polyfunctional monomer may be the same or different. By including polyfunctional monomers in a predetermined proportion in the reaction mixture, crosslinking structures are formed between polymer chains, and a hard polymer with suppressed water content and swelling can be obtained. By copolymerizing an appropriate amount of polyfunctional monomer with a monomer containing an amino group, hydrophobicity and steric hindrance can be introduced around the amino group, lowering the acid dissociation constant of the amino group under carbon dioxide emission conditions and synthesizing a material that efficiently releases carbon dioxide. However, if too much polyfunctional monomer is introduced, the acid dissociation constant of the amino group under carbon dioxide absorption conditions becomes too low, resulting in a decrease in carbon dioxide absorption. Therefore, it is important to design the amount of polyfunctional monomer introduced to be appropriate. Examples of polyfunctional monomers include polyfunctional (meth)acrylamide monomers, polyfunctional (meth)acrylate monomers, and crosslinking agents such as titanium crosslinking agents. Acrylamide monomers (acrylamide derivatives) having two polymerizable groups can be used. N,N'-alkylenebis(meth)acrylamide can be given as an example of an acrylamide monomer having two polymerizable groups. Here, the number of carbon atoms in the alkylene group of N,N'-alkylenebis(meth)acrylamide is not particularly limited, but can be 1 to 12, 1 to 4, or 1 to 2. N,N'-methylenebisacrylamide (BIS) can be given as a specific example of an acrylamide derivative having two polymerizable groups. Furthermore, instead of alkylene groups, crosslinking agents having linear or cyclic crosslinked chains with amino groups, such as oligoethyleneimine, N,N'-bis(2-aminoethyl)-1,3-propanediamine, iminobispropylamine, methyliminobispropylamine, and 1,4-(bisaminopropyl)piperazine, can be used as polyfunctional monomers. Similarly, instead of alkylene groups, crosslinking agents in which oligoethylene glycol constitutes the crosslinked chain can be used as polyfunctional monomers. Another specific example of a polyfunctional (meth)acrylate monomer is ethylene glycol dimethacrylate (EGDMA). These polyfunctional monomers may be used individually or in combination of two or more types.

[0016] [Monomers containing hydrophobic groups] The reaction mixture may contain monomers having hydrophobic groups. A "hydrophobic group" can refer to a functional group that is poorly soluble in water, such as an alkyl group or a phenyl group. The monomer having a hydrophobic group may be, for example, a monofunctional monomer having a hydrophobic group but no amino group, or a polyfunctional monomer having a hydrophobic group. Monofunctional monomers that possess both a hydrophobic group and an amino group can be classified as "monofunctional monomers having an amino group," and polyfunctional monomers that possess a hydrophobic group can be classified as "polyfunctional monomers." Therefore, monofunctional monomers that possess a hydrophobic group but do not possess an amino group are referred to as "monofunctional monomers having a hydrophobic group." Examples of hydrophobic groups that monomers possess include C X H 2X Or C X H 2X+1 Examples of hydrocarbon groups represented by (where X is an integer) include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, cyclopentyl group, isopentyl group, hexyl group, cyclohexyl group, etc. Furthermore, the hydrophobic group may be one in which the hydrogen atom of the above hydrophobic group is substituted with a hydroxyl group, such as hydroxyethyl group, hydroxypropyl group, or hydroxybutyl group. Hydrophobic groups in a monomer may be bonded to the main chain or to the side chains of the polymer, but they can be bonded to the side chains. Furthermore, the number of hydrophobic groups in a monomer is not particularly limited; it may be one or two or more. If a monomer has two or more hydrophobic groups, each hydrophobic group may be the same or different.

[0017] Specific examples of monomers having hydrophobic groups include N-alkylacrylamide, N-alkylmethacrylamide, alkyl acrylate, alkyl methacrylate, N,N-dialkylacrylamide, N-(hydroxyalkyl)acrylamide, (hydroxyalkyl)acrylate, N,N-dialkylmethacrylamide, N-(hydroxyalkyl)methacrylamide, (hydroxyalkyl)methacrylate, N-phenylmethacrylamide, N-phenylmethacrylate, and the like. These polymers having hydrophobic groups may be used individually or in combination of two or more types.

[0018] [Monomer combinations] Examples of combinations of monofunctional monomers and polyfunctional monomers include combinations of monofunctional monomers having an amino group and polyfunctional monomers, combinations of monofunctional monomers that do not have either an amino group or a hydrophobic group and polyfunctional monomers, combinations of monofunctional monomers having a hydrophobic group and polyfunctional monomers, combinations of monofunctional monomers having an amino group and monofunctional monomers having a hydrophobic group and polyfunctional monomers, and combinations of monofunctional monomers having an amino group and monofunctional monomers that do not have either an amino group or a hydrophobic group and polyfunctional monomers. Examples of combinations of monofunctional monomers and polyfunctional monomers containing amino groups include N-(aminoalkyl)(meth)acrylamide and acrylamide derivatives or (meth)acrylates having two polymerizable groups. A specific example is the combination of N,N-dimethylaminopropyl(meth)acrylamide (DMAPM) and N,N'-methylenebisacrylamide (BIS). Examples of combinations of monofunctional monomers having an amino group, monofunctional monomers having a hydrophobic group, and polyfunctional monomers include N-(aminoalkyl)(meth)acrylamide, N-alkyl(meth)acrylamide, and acrylamide derivatives or (meth)acrylates having two polymerizable groups. Specific examples include the combination of N,N-dimethylaminopropyl(meth)acrylamide (DMAPM), N-tert-butylacrylamide (TBAm), and N,N'-methylenebisacrylamide (BIS). Examples of combinations of monofunctional monomers without amino and hydrophobic groups and polyfunctional monomers include combinations of N,N-dialkyl(meth)acrylamide with an acrylamide derivative having two polymerizable groups or a (meth)acrylate having two polymerizable groups, and combinations of N-alkyl(meth)acrylamide with an acrylamide derivative having two polymerizable groups or a (meth)acrylate having two polymerizable groups. Specific examples include combinations of N,N-dimethyl(meth)acrylamide (DMAm) and N,N'-methylenebisacrylamide (BIS), and combinations of N-isopropylacrylamide (NiPAm) and N,N'-methylenebisacrylamide (BIS).

[0019] [solvent] The solvent functions as the reaction medium for polymerization reactions. The presence of a solvent in the reaction mixture allows for the synthesis of polymers with appropriate spacing around the amino groups. Therefore, polymers obtained by polymerizing with an appropriate amount of solvent tend to have higher reversible gas absorption capacity. Examples of solvents include water, alcohols (methanol, ethanol, isopropanol, etc.), and polar solvents such as dimethyl sulfoxide. Mixed solvents of two or more of these polar solvents may also be used. Alternatively, water, or a mixed solvent of water and another polar solvent, a mixed solvent of water and alcohol, water and ethanol, or a mixed solvent of water and methanol may be used. The volume ratio of water to alcohol (water:alcohol) can be 1:0 to 1:1, 1:0.2 to 1:0.8, or 1:0.3 to 1:0.5. The solvent may also contain salts or polymers soluble in the solvent.

[0020] [Initiating agent] An initiator is a compound added to start the polymerization reaction of a monomer, and compounds that can be converted into highly reactive intermediates by applying energy can be used. For example, thermal polymerization initiators that generate active species such as radicals and cations upon heating, and photopolymerization initiators that generate active species such as radicals, cations, and anions upon light irradiation can be used. Examples of thermal radical polymerization initiators include azo compounds such as 2,2'-azobis(2-methylpropionitrile) (AIBN), 2,2'-azobisbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile) (V-65), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), as well as peroxides such as benzoyl peroxide, tert-butyl hydroperoxide, hydrogen peroxide solution, persulfates, and tert-butyl hydroperoxide + ferrous sulfate. Examples of thermal cationic polymerization initiators include benzenesulfonic acid esters and alkylsulfonium salts. Furthermore, examples of initiators that generate radicals by ultraviolet irradiation or electron beam irradiation include benzoin derivatives, benzyl derivatives, acetophenone derivatives, benzophenone derivatives, and azo derivatives. Initiators such as AIBN may be used after purification (recrystallization) or without purification.

[0021] [Surfactants] Surfactants and other additives may be added to the reaction mixture as needed. This allows for the synthesis of a homogeneous polymer. As additives, amphiphilic polymers such as polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol, their oligomers, or ionic surfactants such as cetyltrimethylammonium bromide can be used.

[0022] [Polymerization reaction] In the manufacturing method, polymers are produced by polymerizing monomers in a reaction mixture containing monofunctional monomers, polyfunctional monomers, a solvent, and an initiator as described above. At this time, the total monomer concentration of the reaction mixture is set to 0.7 mol / L or higher, and the proportion of polyfunctional monomers among the monomers contained in the reaction mixture can be greater than 10 mol% and less than or equal to 30 mol%. Here, the "total monomer concentration" of the reaction mixture can refer to, for example, the total number of moles of all monomers contained in 1 L of the reaction mixture. When monomers are polymerized in the above reaction mixture, a polymer is synthesized having polymer chains containing constituent units derived from monofunctional monomers and crosslinked structures derived from polyfunctional monomers. In this production method, the total monomer concentration of the reaction mixture can be set relatively high, at 0.7 mol / L or higher, allowing polymer chains to efficiently form non-covalent crosslinking sites through interactions and entanglement within a limited volume of the reaction mixture. Furthermore, polymerization can be carried out in a state where the structure is stabilized by covalent crosslinking with a crosslinking agent. As a result, the polymer does not absorb excessive water or deform in a wet state. A polymer with low swelling properties, i.e., a high reversible gas absorption per unit volume, can be synthesized in high yield while maintaining a reversible gas absorption per unit mass. Furthermore, the total monomer concentration can be set to 0.7 mol / L or higher, and the proportion of polyfunctional monomers among the monomers can be set to 10 mol% or higher, so that a relatively dense crosslinking structure is formed between polymer chains. This results in a polymer that is hard and has lower water content and swelling properties. In addition, the upper limit of the total monomer concentration can be set to 4 mol / L, and the upper limit of the proportion of polyfunctional monomers can be set to 30 mol%, so that the decrease in reversible gas absorption per unit mass due to excessively high concentrations can be suppressed. As a result, polymer materials with a large reversible gas absorption per unit volume can be manufactured productively.

[0023] The total concentration of monomers in the reaction mixture can be, for example, 1.0 to 2.8 mol / L, or 1.5 to 3 mol / L. The proportion of polyfunctional monomers among the monomers can be, for example, more than 10 mol% and 30 mol% or less, and 15 mol% or more and 30 mol% or less. When a reaction mixture contains a monofunctional monomer having an amino group, the proportion of the monofunctional monomer having an amino group among the monomers can be, for example, 1 to 95 mol%, 5 to 90 mol%, or 30 to 85 mol%. When a reaction mixture contains a monofunctional monomer having a hydrophobic group, the proportion of the monofunctional monomer having a hydrophobic group among the monomers can be, for example, 1 to 50 mol%, 5 to 45 mol%, or 10 to 43 mol%. When the reaction mixture contains monofunctional monomers having amino groups and monofunctional monomers having hydrophobic groups, the molar ratio of the monofunctional monomers having amino groups to those having hydrophobic groups can be, for example, 95:5 to 5:95, or 3:1 to 1:2.

[0024] The procedure for mixing the components of the reaction mixture is not particularly limited, but when using monofunctional monomers having amino groups and monofunctional monomers having hydrophobic groups in combination, a mixture containing the monofunctional monomers having amino groups, polyfunctional monomers, and water can be heated, and then the monofunctional monomers having hydrophobic groups can be added to this mixture, or the monofunctional monomers having hydrophobic groups can be added to the mixture as an alcohol solution. This allows for uniform mixing of each monomer while keeping the amount of solvent to a minimum. The reaction temperature of the reaction mixture can be, for example, 0 to 200°C, 30 to 120°C, or 50 to 105°C. The reaction time can be, for example, 0.1 to 5 hours, or 0.2 to 3 hours.

[0025] [Post-treatment of polymers] In the manufacturing method of the present invention, a low-swelling polymer is formed as a precipitate in the reaction solution, or the entire reaction solution gels. The formed polymer may be mechanically pulverized to obtain a slurry or powder, or the liquid component may be removed from the reaction solution, and the remaining precipitate (polymer) may be mechanically pulverized to obtain a powder. Alternatively, the obtained powder may be suspended in a dispersion medium to prepare a slurry. Gel pulverization can be performed using various types of pulverizers. For example, jaw crushers, gyroscopes, impact crushers, roll crushers, edge runners, disintegrators, SAG mills, self-generating mills, ball mills, rod mills, jet mills, grinders, extrusion / shearing mills, meat choppers, and fit mills can be used. Alternatively, the prepared slurry may be applied and dried to form a porous film made of polymer powder, or the slurry may be filtered to leave a polymer film on the filter, which is then dried to form a polymer film or packed layer. Conventional polymer particles used in gas absorbent materials swell when they absorb moisture, causing the voids between particles to become blocked. This makes it difficult to remove moisture from between particles, hindering filtration and drying. In contrast, the polymer powder of the present invention has low swelling properties, allowing it to be easily molded into film or packed bed shapes by methods such as filtration. The polymer, once molded into a film or packed, can be redispersed in water after storage to form another film or refill, or mixed with resin to form another film. Methods for applying the slurry include, for example, the sand paper method, spray coating method, casting method, bar coating method, roll coating method, wire bar coating method, and dip coating method. Furthermore, the polymer precipitate formed in the reaction solution, the powder, slurry, and film prepared from the precipitate may be freeze-dried or spray-dried. Alternatively, they may be dried with hot air using a fluidized bed. The polymer of the present invention maintains appropriate swelling properties without excessive water absorption even when dispersed again in water after freeze-drying. When re-swelling after drying, an acid such as hydrochloric acid or carbon dioxide may be added. Alternatively, a resin with low volatility and high hydrophilicity, such as polyethylene glycol or glycerin, may be added during drying to accelerate re-swelling. Furthermore, powders, slurries, films, and freeze-dried versions thereof prepared from polymer precipitates can be washed as needed and used as gas absorbent materials as described below.

[0026] [2] Amine impregnation process In the manufacturing method of the present invention, a polymer material is obtained by impregnating the polymer obtained in the polymer synthesis step [1] with a treatment solution containing an amine (hereinafter referred to as "amine-containing treatment solution"). However, if a monofunctional monomer containing an amino group is used in the polymer synthesis step [1], the amine impregnation step may be omitted. When a polymer is impregnated with an amine-containing treatment solution, the amine-containing solution penetrates and diffuses between the polymer chains, resulting in the polymer becoming amine-containing. At this time, the polymer obtained in the polymer synthesis process has a relatively dense cross-linked structure between the polymer chains, making it less prone to swelling even when impregnated with the amine-containing treatment solution, and thus maintaining a rigid state. The polymer material obtained in this way exhibits excellent reversible gas absorption capacity because the swelling of the polymer is suppressed, allowing for good gas diffusion during filling, and because the amino groups of the amine and the amino groups derived from the monofunctional monomers effectively function as functional groups that reversibly absorb gas. The amine-containing treatment solution used in the amine impregnation process and the conditions for the amine impregnation process will be described below.

[0027] [Amine-containing treatment solution] The amine-containing treatment solution used in the amine impregnation process can be any liquid material containing an amine, for example, an amine solution prepared by dissolving an amine in a solvent, or a liquid amine. The amine-containing treatment solution may also contain an appropriate amount of water.

[0028] (amine) The amine contained in the amine-containing treatment solution may be either a low-molecular-weight amine or a high-molecular-weight amine. The molecular weight of the amine can be, for example, 61 to 10,000, or 75 to 1,000, or 90 to 500. For a description and specific examples of compounds that can be used as amines, please refer to the description and specific examples of low-molecular-weight amines in the description of absorption enhancers and release enhancers described later.

[0029] (solvent) When an amine solution is used as the amine-containing treatment solution, the solvent can be one that can dissolve the amine as a solute, has high compatibility with the polymer, and has high solubility for carbon dioxide and bicarbonate ions. Specifically, water, ethylene glycol, glycerin, etc., can be used, and a mixed solvent combining two or more of these solvents may also be used. The amine concentration in the amine solution can be, for example, 0.1 to 12N, 1 to 10N, or 3 to 9N in terms of amine concentration.

[0030] (Other ingredients) Other components besides amines and solvents may be added to the amine-containing treatment solution. Examples of other components include antioxidants and other antioxidants.

[0031] [Conditions for amine impregnation treatment] Impregnation of a polymer with an amine-containing treatment solution (amine impregnation treatment) can be carried out, for example, by immersing the polymer in an amine-containing treatment solution. The polymer subjected to the treatment may be dried or swollen with a liquid such as water. When a polymer swollen with a liquid is immersed in an amine-containing treatment solution, at least a portion of the liquid is replaced by the amine-containing treatment solution, resulting in a polymer material containing the amine-containing treatment solution, or a mixture of the liquid and the amine-containing treatment solution, internally. The amount of amine-containing treatment solution used in the amine impregnation treatment can be, for example, 0.1 to 10 times, 0.2 to 5 times, or 0.3 to 3 times the mass of the polymer to be treated. The temperature of the amine-containing treatment solution can be, for example, 5 to 100°C, 10 to 80°C, or 15 to 60°C. The processing time for amine impregnation varies depending on the concentration and temperature of the amine-containing treatment solution, but can be, for example, 0.1 to 100 hours, 1 to 24 hours, or 2 to 12 hours. Furthermore, the amine impregnation treatment can be carried out while shaking the amine-containing treatment solution in which the polymer is immersed.

[0032] <Polymer materials> Next, the polymer material of the present invention will be described. The polymer material of the present invention is characterized by being manufactured by the manufacturing method of the present invention. For a description of the manufacturing method of the present invention, please refer to the section above titled "Method for Manufacturing Polymer Materials." The polymer material of the present invention can be described as follows: (A) a polymer having a polymer chain containing structural units derived from a monofunctional monomer and a crosslinked structure derived from a polyfunctional monomer, and containing an amine derived from an amine-containing treatment solution; and (B) a polymer having a polymer chain containing structural units derived from a monofunctional monomer having an amino group and a crosslinked structure derived from a polyfunctional monomer, but without containing any components derived from an amine-containing treatment solution. The monofunctional monomer in embodiment (A) and the polyfunctional monomer in embodiment (B) may or may not have an amino group. The polymer material of the present invention can selectively absorb acidic gases such as carbon dioxide and hydrogen sulfide by containing an amino group in at least one of the polymer structural units and the impregnated amine. Furthermore, by heating, a phase transition occurs, such as a decrease in pKa and an increase in hydrophobic interactions of hydrophobic groups, causing the absorbed acidic gas to be released. In other words, the polymer material of the present invention has a reversible gas absorption capacity that selectively and reversibly absorbs acidic gases. In addition, since the polymer material of the present invention is manufactured by the manufacturing method of the present invention, it has low water content and swelling properties. Therefore, when commercializing the product as a gas absorbent or gas separator, a sufficiently large volume packing ratio can be achieved. Furthermore, when a gas containing water is passed through a gas recovery device to which the product is applied, the polymer absorbs water and swells, but it can only absorb a limited amount of water, thus limiting the degree of expansion. As a result, a sufficient gas flow path can be secured, and the amount of heat required for the heating process for gas release can be kept low. In addition, even when liquid water is added to the absorbent material, the gaps between the water-containing polymers are maintained, ensuring a sufficient water flow path, and the water can be easily discharged by the subsequent gas flow, allowing gas to be introduced into the gaps. For these reasons, the polymer material of the present invention can be effectively used as a gas absorbent material for reversibly absorbing acidic gases such as carbon dioxide, and this gas absorbent material can be effectively used as a gas separator material for separating acidic gases from mixed gases. The following describes the average molecular weight of the polymer contained in the polymer material of the present invention, the amount of each group if the polymer has amino groups or hydrophobic groups, the physical properties of the polymer, and the amine content if the polymer material contains amines.

[0033] [Average molecular weight of polymer, amount of amino groups and hydrophobic groups] If the polymer contains amino groups, the amount of amino groups can be, for example, 1 mmol / g to 23 mmol / g, or 1 mmol / g to 18 mmol / g, or 2 mmol / g to 7 mmol / g. Alternatively, the proportion of monomers containing amino groups in the total monomer can be, for example, 5 to 100 mol%, or 30 to 100 mol%, or 50 to 90 mol%. If the polymer has hydrophobic groups, the amount of these hydrophobic groups can be, for example, 1 mol% to 50 mol%, 5 mol% to 45 mol%, or 10 mol% to 43 mol%. The degree of crosslinking of the polymer can be, for example, 0 mol% to 50 mol%, 5 mol% to 40 mol%, or 10 mol% to 30 mol%. If the polymer material contains amines, the amine content can be, for example, 1 to 30 mmol / g, 2 to 20 mmol / g, or 3 to 10 mmol / g per dry weight of the polymer.

[0034] [Degree of polymer swelling] The degree of swelling of the polymer contained in the polymer material of the present invention can be evaluated, for example, by the amount of water it contains when immersed in water for a long period of time.

[0035] [Water content of polymers] The polymer contained in the polymer material of the present invention can have a water content of, for example, 4 grams / gram polymer or less, or 3 grams / gram polymer or less, or 2 grams / gram polymer or less when swollen with an excess amount of water. Here, the "water content" of a polymer refers to the value obtained by the following formula, where M1 is the weight of the polymer in its wet state after adding an excess amount of water and letting it stand overnight at room temperature, then pulverizing the polymer with a hand blender, and removing the water by filtration using filter paper or a metal mesh, and M0 is the weight of the polymer after drying by freeze-drying or natural drying. Water content = (M1-M0) / M0

[0036] [Reversible gas absorption capacity of polymer materials] The polymer material can have a reversible CO2 absorption capacity of, for example, 30 mL / g or more, 45 mL / g or more, or 60 mL / g or more per dry polymer weight. This allows for efficient absorption and recovery of carbon dioxide contained in exhaust gas when applied, for example, to a gas recovery device that recovers carbon dioxide from exhaust gas. For information on how to measure the amount of reversible CO2 absorption, please refer to the section on (CO2 reversible absorption test) in the examples.

[0037] [Modes of polymer materials] The embodiments of the polymer material of the present invention are not particularly limited and may be, for example, powder, slurry, film, bulk, etc. For methods of producing powder, slurry, and film, refer to the description in the [Post-treatment of polymer] section of the method for producing polymer material.

[0038] <Gas absorbent material> Next, the gas-absorbing material of the present invention will be described. The gas-absorbing material of the present invention contains the polymer material of the present invention. The gas-absorbing material of the present invention, by containing the polymer material of the present invention, has a reversible gas absorption capacity that absorbs acidic gases such as carbon dioxide and hydrogen sulfide or water vapor, and then releases the acidic gas or water vapor due to changes in temperature or gas partial pressure. For a description of the polymer material of the present invention, please refer to the description in the <Polymer Material> section above. The gas-absorbing material of the present invention may contain components other than the polymer material of the present invention (other components). Examples of other components that can be used in the gas-absorbing material include water, pKa adjusters, absorption enhancers, release enhancers, hygroscopic agents, antioxidants, thermoplastic resins, fillers, etc. Water can be added to the gas-absorbing material by intentionally adding water, for example, using water or water vapor. When adding water, for example, carbon dioxide gas or bicarbonate ions can also be added.

[0039] [pKa adjuster] pKa modifiers can be added, for example, during polymerization to adjust the pKa of the polymer after polymerization to a desired value. This allows control over the type of gas absorbed by the polymer, the type of gas or liquid that selectively permeates the gas-absorbing material, the permeation flux, and the selectivity of the target gas to other gases. As pKa modifiers, those that can protonate or deprotonate the amino groups of the polymer can be used, such as acids like hydrochloric acid or bases like sodium hydroxide, which can be used by adjusting their concentration as appropriate according to the desired pKa. Furthermore, the pKa of the amine can be controlled by adjusting the local environment around the amine in the polymer, such as polymer density, interamine distance, and polarity, by adjusting the crosslinking rate of polyfunctional monomers, so the above-mentioned polyfunctional monomers may also be used as pKa modifiers. Additionally, the pKa of the amine can be controlled by adjusting the local environment around the amine, such as polymer density, interamine distance, and polarity, by adding hydrophobic monomers or alcohols or hydrophilic polymers during polymerization, so these may also be used as pKa modifiers.

[0040] [Absorption enhancers, release enhancers] The absorption accelerator is a compound that has the function of promoting the absorption of acidic gases into the polymer of the present invention. The release accelerator is a compound that has the function of promoting the release of acidic gases from the polymer. In the present invention, an absorption-release accelerator having both the functions of an absorption accelerator and a release accelerator may be used. These absorption accelerators, release accelerators, and absorption-release accelerators may also function as stabilizers that stabilize the gas-absorbing material. The total content of the absorption accelerator, release accelerator, and absorption-release accelerator in the gas-absorbing material of the present invention can be, for example, 0.05 mL or more, or 0.1 mL or more, per gram of solid content. Furthermore, the content of the absorption accelerator in the gas-absorbing material can be, for example, 0.1 to 12 N, 1 to 10 N, or 3 to 9 N in terms of amine concentration. Low molecular weight amines can be used as absorption enhancers, release enhancers, or absorption-release enhancers. The molecular weight of the low molecular weight amine may be, for example, 61 to 10000, 75 to 1000, or 90 to 500. The boiling point of the low molecular weight amine may be, for example, 80°C or higher, 120°C or higher, or 150°C or higher, as this is practical for long-term use. For boiling point elevation, amine-containing compounds that have a site that forms a salt with a counterion like an ionic liquid and are liquid may also be used. Low molecular weight amines may contain primary, secondary, or tertiary amino groups, as well as ammonium and imidazolium groups. Multiple amino, ammonium, or imidazolium groups may be present, for example, 1 to 3 groups. Secondary and tertiary amino groups may also be cyclic amino groups. Furthermore, low molecular weight amines may contain functional groups other than amino, ammonium, or imidazolium groups, such as hydroxyl groups. Low molecular weight amines may contain 0 to 2 hydroxyl groups. Examples of low molecular weight amines include amines having an amino group and a hydroxyl group, or amines having three amino groups. For example, amines having a secondary amino group and a hydroxyl group can be used. Because they can dramatically increase the amount of acidic gas released, especially in high concentration ranges, and are suitable for repeated use, amines having a secondary amino group and a hydroxyl group with a boiling point of 150°C or higher may be selected. Examples of low-molecular-weight amines include specific compounds represented by the following formula.

[0041] [ka]

[0042] Among these, DMAE, IPAE, Bis(2DMAE)ER, 1-2HE-PRLD, 1-2HE-PP, TM-1,4-DAB, TMHAD, and PMDETA may be selected in particular because they can release a large amount of acidic gas. Among these, IPAE, Bis(2DMAE)ER, 1-2HE-PP, TM-1,4-DAB, TMHAD, and PMDETA may be selected because they have relatively high boiling points and do not evaporate easily. IPAE, TM-1,4-DAB, TMHAD, and PMDETA may also be selected because their concentration can significantly increase the release of acidic gas. IPAE, TMHAD, and PMDETA may also be selected because they are readily available.

[0043] [Desiccant] The desiccant that can be used as an additive is one that, when prepared as a saturated aqueous solution, has a relative humidity of 90% or less at 25°C. Examples of such desiccant ions include bromide ions, chloride ions, acetate ions, carbonate ions, bicarbonate ions, lithium ions, potassium ions, calcium ions, magnesium ions, and sodium ions. Salts such as lithium bromide, lithium chloride, calcium chloride, potassium acetate, magnesium chloride, potassium carbonate, and sodium carbonate can also be used as desiccant ions. When adding a desiccant, the amount added can be, for example, 0.01 to 10% by mass relative to the total amount of gas absorbent material.

[0044] [Antioxidant] Antioxidants that can be used as additives are those that can suppress or prevent oxidation when added. Examples of such antioxidants include vitamin C (ascorbic acid), vitamin E (tocopherol), BHT (dibutylhydroxytoluene), BHA (butylhydroxyanisole), sodium erythorbate, propyl gallate, sodium sulfite sulfur dioxide, hydroquinone and its derivatives. When adding antioxidants, the amount added can be, for example, 0.01 to 10% by mass relative to the total amount of gas absorbent material.

[0045] [Thermoplastic resin] The gas-absorbing material may contain a thermoplastic resin. This allows the thermoplastic resin, the polymer of the present invention, and other components added as needed to be kneaded together and molded into pellets or films. As the thermoplastic resin, known materials can be used. For example, polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers, modified polyolefins, polyamides, thermoplastic polyimides, liquid crystal polymers such as aromatic polyesters, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, polyethers, polyetheretherketones, polyetherimides, polyacetals, styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based, polyester-based materials such as polyethyl polylactic acid, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, polyvinyl chloride, polyvinylidene chloride-based chlorinated polyethylene-based materials, and various thermoplastic elastomers, or copolymers, blends, polymer alloys mainly composed of these, etc. For example, polyolefin resins such as polyethylene can be selected. When a thermoplastic resin is included in the gas-absorbing material, the content of the thermoplastic resin can be, for example, 10 to 40% by mass relative to the total amount of the gas-absorbing material.

[0046] [Filler] The gas-absorbing material may contain a filler. This allows for the formation of voids in the gas-absorbing material, promoting the diffusion of gas into the material and improving the reversible absorption rate and amount of gas. Furthermore, by using a filler with gas adsorption capacity, it is possible to enable gas adsorption by the adsorbent in addition to the gas absorption of the absorbent material. Since gas adsorbents are known to exhibit high reversible gas adsorption capacity at low humidity and gas-absorbing materials exhibit high gas absorption performance at high humidity, using a gas adsorbent as a filler makes it possible to realize a material with high reversible gas adsorption capacity over a wide range of humidity conditions. As a filler with gas adsorption capacity, for example, materials with a large pore area such as various activated carbons and zeolites may be used. In particular, an adsorbent with high carbon dioxide gas adsorption capacity may be selected and used. In addition, if the polymer material constituting the gas-absorbing material is gelled with water or is a pulverized gelled polymer (polymer pulverized material), adding a filler reduces the bulk and increases the packing amount, thereby improving the reversible gas absorption capacity. Fine particles with a primary particle diameter of 1000 nm or less, as described later, can preferably be used as the filler. Furthermore, grinding the polymer pulverized material and the gas-absorbing material containing the filler can further improve its reversible gas absorption capacity. This grinding of the polymer pulverized material and the gas-absorbing material containing the filler can be carried out using a planetary ball mill device such as a bead mill. To promote gas diffusion into the absorbent material, the filler may be selected in powder form. Alternatively, the primary particle diameter may be, for example, 1000 nm or less. The primary particle diameter can be measured by transmission electron microscopy. The fine particles with a primary particle diameter of 1000 nm or less used in this invention may consist only of fine particles with a primary particle diameter of 1000 nm or less. The particle size can be 0.1 nm to 1000 nm, or 0.3 nm to 500 nm, or 0.5 nm to 300 nm, or 1 nm to 200 nm, or 1.5 nm to 100 nm, or 2 nm to 50 nm, or 2.5 nm to 25 nm in average primary particle diameter. This tends to lead to a more reliable formation of the gas diffusion phase in the molded body of the gas absorbent material, and a greater improvement in the gas absorption rate and emission rate. The fine particles may be aggregated primary particles. The aggregates are preferably 100 nm to 200 μm in size, more preferably 500 nm to 100 μm, and most preferably 2.5 μm to 50 μm. In addition, fillers with a water contact angle of, for example, 70° or more may be used. The water contact angle may be 80° or more, or 100° or more, or 110° or more, or 120° or more, or 130° or more, or 140° or more.

[0047] Fine particles with a primary particle size of 1000 nm or less In the following, we will specifically describe fine particles with a primary particle diameter of 1000 nm or less that can be used as fillers. Fine particles with a primary particle diameter of 1000 nm or less may be composed of inorganic materials, organic materials, or a combination of organic and inorganic materials. Furthermore, the fine particles may be hydrophobic or hydrophilic, but hydrophobic particles are preferred. By being hydrophobic, the voids formed by the fine particles are prevented from being blocked by the moisture contained in the gas-absorbing material, and these voids function effectively as a gas diffusion phase. Here, the "water-repellent fine particles" mean fine particles having a primary particle diameter of 1000 nm or less and a water contact angle of 70° or more. The "water contact angle" of the fine particles refers to the contact angle with water measured on the surface of the fine particle deposition film formed by the fine particles. The water contact angle of the surface of the fine particle deposition film can be measured by the measurement of the static contact angle with water. The water contact angle of the water-repellent fine particles is preferably 80° or more, more preferably 100° or more, still more preferably 110° or more, still more preferably 120° or more, particularly preferably 130° or more, and most preferably 140° or more.

[0048] (Water-repellent fine particles) The water-repellent fine particles having a primary particle diameter of 1000 nm or less may be fine particles having water repellency by themselves, or may be those obtained by imparting water repellency to the surface of a base material particle (base material). Examples of the fine particles obtained by imparting water repellency to the surface of the base material particle include coated fine particles having a water-repellent film formed on the surface of the base material and surface-modified fine particles having a surface modification for imparting water repellency to the base material particle. First, carbon black can be cited as fine particles having water repellency by themselves. Examples of carbon black include acetylene black, furnace black, channel black, thermal black, lamp black, ketjen black, etc., and among them, acetylene black is preferable. Other water-repellent fine particles include fine particles composed of Knovel (porous carbon, manufactured by Toyo Carbon Co., Ltd.), titanium oxide, mesoporous silica, etc. In addition, fine particles formed of a water-repellent organic material can also be used as the fine particles having water repellency by themselves. Examples of the water-repellent organic material that can be used for forming the particles include fluororesins containing a structural unit represented by -(CA 1 A 2 -CA 3 A 4 )- (however, A 1 ~A 4A represents a hydrogen atom, a fluorine atom, a chlorine atom, or a perfluoroalkyl group. 1 ~A 4 (At least one of the atoms is a fluorine atom). Specific examples of fluororesins include polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and other monomers, polychlorotrifluoroethylene (PCTFE), copolymers of chlorotrifluoroethylene and other monomers, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and polytetrafluoropropylene (HEP). Examples of copolymers of tetrafluoroethylene and other monomers include perfluoroalkoxyalkanes (PFA: copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether), perfluoroethylenepropene copolymer (FEP: copolymer of tetrafluoroethylene and hexafluoropropylene), ethylene-tetrafluoroethylene copolymer (ETFE), and tetrafluoroethylene-perfluorodioxole copolymer (TFE / PDD). An example of a copolymer of chlorotrifluoroethylene and other monomers is ethylene-chlorotrifluoroethylene copolymer (ECTFE). These water-repellent organic materials may be used individually or in combination of two or more types.

[0049] The base particles of coated fine particles and surface-modified fine particles may be inorganic or organic particles, but inorganic particles are preferred. Furthermore, if fine particles that are themselves water-repellent are used as the base particles, and a water-repellent coating or surface modification that imparts water repellency is applied to these fine particles, the gas absorption rate and emission rate, as well as the amount of gas absorbed and emitted, can be improved. As inorganic particles, known materials can be used, including carbon black such as acetylene black, furnace black, channel black, thermal black, lamp black, and Ketjen black; particles made of inorganic compounds such as oxides, hydroxides, nitrides, halides, carbonates, sulfates, acetates, and phosphates of metallic or metalloid elements; and natural mineral particles. Examples of inorganic compounds of metallic or metalloid elements include lithium fluoride, calcium carbonate, calcium phosphate, calcium sulfate, calcium fluoride, barium sulfate, titanium dioxide (titania), zirconia dioxide (zirconia), aluminum oxide (alumina), aluminasilicate (alumina silicate, kaolin, kaolinite), and silicon dioxide (silica, silica gel). Examples of natural minerals include talc and clay. Among these, particles made of carbon black and silicon dioxide are preferred. Known organic particles can be used, including particles made of styrene-based, acrylic-based, melamine-based, benzoguanamine-based, and silicone-based polymers. Fillers may also be used in combination; for example, activated carbon and zeolite can be preferably used as fillers.

[0050] For the water-repellent coating formed on the base particles, in addition to the water-repellent organic materials exemplified as water-repellent materials that can be used to form fine particles, coatings of organopolysiloxanes and organohydrogenpolysiloxanes can be used. Examples of organopolysiloxanes include dialkylpolysiloxanes and alkylphenylpolysiloxanes, and examples of organohydrogenpolysiloxanes include alkylhydrogenpolysiloxanes. The alkyl groups in dialkylpolysiloxanes, alkylphenylpolysiloxanes, and alkylhydrogenpolysiloxanes may be linear, branched, or cyclic, but linear is preferred. The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6. Here, the two alkyl groups bonded to the silicon atom may be the same or different. Specific examples of organopolysiloxanes include dimethylpolysiloxane and methylphenylpolysiloxane, while specific examples of organohydrogenpolysiloxanes include methylhydrogenpolysiloxane.

[0051] Surface modification methods for substrate particles include introducing water-repellent groups such as alkyl groups and alkyl fluoride groups onto the surface of the substrate particles. The alkyl groups and alkyl fluoride groups introduced into the substrate particles may be linear, branched, or cyclic, but linear is preferred. The number of carbon atoms in the alkyl groups and alkyl fluoride groups is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10. Furthermore, the alkyl fluoride groups may be partially fluorinated alkyl groups in which some of the hydrogen atoms of the alkyl group are replaced with fluorine atoms, or perfluoroalkyl groups in which all of the hydrogen atoms are replaced with fluorine atoms.

[0052] Surface modification to introduce these water-repellent groups into substrate particles can be carried out using silane coupling agents or silazanes or other silane compounds. Examples of silane coupling agents include compounds represented by the following general formula (1). General formula (1) R 1 n SiX (4-n) (In general formula (1), X represents a hydrolyzable group that generates a silanol group by hydrolysis, and R 1 (where n is an integer between 1 and 3.) The silane coupling agent represented by general formula (1) introduces water-repellent groups to the substrate particles by the reaction of silanol groups and silyl groups generated by the hydrolysis of X with functional groups on the surface of the substrate particles. In the general formula, the "hydrolysis group that generates a silanol group" represented by X can include alkoxy groups such as methoxy groups and ethoxy groups, halogen groups, and the like. R 1 Examples of water-repellent groups in this material include alkyl groups, alkyl fluorides, and dimethylsiloxanes. For a description of alkyl groups and alkyl fluorides and their preferred ranges, please refer to the description of water-repellent groups that can be introduced onto the surface of the substrate particles and their preferred ranges. The water-repellent groups may be directly bonded to Si or bonded via linking groups. n is an integer from 1 to 3, preferably 1 or 2. When n is 2 or greater, multiple R 1 The elements may be identical or different from each other. When n is 2 or less, multiple X elements may be identical or different from each other. Examples of silane coupling agents represented by general formula (1) include triethoxyalkylsilane, diethoxydialkylsilane, ethoxytrialkylsilane, trimethoxyalkylsilane, dimethoxydialkylsilane, methoxytrialkylsilane, and trichloroalkylsilane. Specific examples of silane coupling agents include triethoxycaprylylsilane (triethoxy-n-octylsilane) and octadecyltrichlorosilane. The formation of a water-repellent coating and surface modification treatment on the above-mentioned substrate particles can be carried out according to conventional methods.

[0053] Examples of commercially available water-repellent microparticles include Microdispers-200 (manufactured by Techno Chemical Co., Ltd.), AEROSIL RY200, AEROSIL RY300, AEROSIL R805 (all manufactured by Evonik Co., Ltd.), and Ketjenblack (manufactured by Lion Specialty Chemicals Co., Ltd.). The above-mentioned water-repellent fine particles may be used individually or in combination of two or more types.

[0054] (Fine particles other than water-repellent fine particles) The fine particles with a primary particle diameter of 1000 nm or less that can be used as fillers are not limited to water-repellent fine particles, but may also be fine particles other than water-repellent fine particles, i.e., fine particles with a water contact angle of less than 70°. Furthermore, water-repellent fine particles and fine particles with a water contact angle of less than 70° may be used in combination. Fine particles with a water contact angle of less than 70° may have a water contact angle of 50° or less, 30° or less, or 10° or less. The lower limit of the water contact angle of fine particles is 0°. Other fine particles besides water-repellent fine particles include particles made of inorganic compounds of metallic and metalloid elements, as well as organic particles, as described in the (water-repellent fine particles) section above as examples of base particles for coated fine particles and surface-modified fine particles, and silicon dioxide particles are preferred. Furthermore, these inorganic and organic particles may have a coating of organic compounds formed on their surface, or organic functional groups may be introduced into them. A commercially available example of fine particles other than water-repellent fine particles is AEROSIL 200 (manufactured by Evonik).

[0055] (Specific surface area of ​​fine particles) The specific surface area of ​​fine particles is 1 to 3000 m². 2 It is preferably / g, and 2.5 to 2750m 2 It is more preferable that the value be / g, and 5 to 2500m 2 It is even more preferable that the concentration is / g. This ensures that the gas diffusion phase is more reliably formed in the molded body of the gas-absorbing material, and tends to improve the gas absorption rate and emission rate. The specific surface area of ​​fine particles can be measured by the BET method.

[0056] Ratio of polymer material to fine particles with a primary particle size of 1000 nm or less The mixing ratio of polymer material to fine particles by weight of solid content (polymer material:fine particles) is preferably 95:5 to 5:95, more preferably 90:10 to 30:70, and even more preferably 80:20 to 50:50. Furthermore, the content of polymer material in the gas absorbent material is preferably greater than the content of water-repellent fine particles in terms of solid content. In addition, when the polymer material is gelled with water or is a pulverized gelled polymer, adding a filler to the gas absorbent material reduces the bulk and increases the filling capacity, improving the reversible gas absorption performance. To effectively obtain such effects, the volume ratio of gelled polymer or its pulverized material to fine particles (gelled polymer or its pulverized material:fine particles) is preferably 99.9:0.1 to 98:2, more preferably 99.75:0.25 to 98.5:1.5, and even more preferably 99.5:0.5 to 99:1. By setting the ratio of polymer material to fine particles within the above range, the gas absorption rate and emission rate tend to increase. However, the gas-absorbing material of the present invention is not limited to containing fine particles with a primary particle diameter of 1000 nm or less. In other words, the gas-absorbing material of the present invention does not have to contain fine particles with a primary particle diameter of 1000 nm or less.

[0057] Other fillers In addition to the fine particles exemplified above, known fillers can be used in the gas-absorbing material of the present invention. For example, activated carbon, zeolite, silica, fumed silica, hydrophobic silica, hydrophobic fumed silica, hydrophobic silica, alumina, hydrophobic alumina, hydrophobic alumina, boehmite, diatomaceous earth, oxides such as titanium dioxide, iron oxide, zinc oxide, magnesium oxide, and metal ferrite, hydroxides such as aluminum hydroxide and magnesium hydroxide, carbonates such as calcium carbonate (light and heavy), magnesium carbonate, dolomite, and dawsonite, sulfates or sulfites such as calcium sulfate, barium sulfate, ammonium sulfate, and calcium sulfite, talc, mica, clay, and glass fibers. Examples of fillers include silicates such as calcium silicate, montmorillonite, and bentonite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; carbon such as carbon black, hydrophobic carbon black, water-repellent carbon black, graphite, and carbon fibers; and other materials such as iron powder, copper powder, aluminum powder, zinc oxide, molybdenum sulfide, boron fibers, potassium titanate, lead zirconate titanate, fluorinated resin powder, and Teflon® powder. Hydrophobic substances can be selected and used to suppress the condensation of water vapor. Materials made of carbon, such as carbon black, can also be selected and used. These fillers may have a primary particle size of 1000 nm or less, or greater than 1000 nm. Furthermore, the gas-absorbing material of the present invention may contain particles made of the same material as those exemplified as fine particles with a primary particle size of 1000 nm or less, and may also contain particles with a primary particle size greater than 1000 nm. When a filler is included in the gas absorbent material, the filler content can be, for example, 0.1 to 60% by mass relative to the total amount of the gas absorbent material.

[0058] [Dispersion medium] The gas-absorbing material may include a dispersion medium for suspending the polymer material and additives of the present invention. For preferred ranges and specific examples of dispersion media, refer to the description in the [solvent] section of the method for producing the polymer material.

[0059] The other components that can be used in the gas-absorbing material described above may be used individually or in combination of two or more types.

[0060] <Methods of use of gas absorbent materials> The gas-absorbing material containing the polymer material of the present invention can be used in various ways. Examples of how the gas-absorbing material can be used include filling the gas-absorbing material into a container such as a drum, forming the gas-absorbing material into a sheet and creating a laminate or roll with nonwoven fabric or mesh, filling the inside of a filter with the gas-absorbing material, kneading the gas-absorbing material with a hard material such as polyethylene and forming it into a self-supporting membrane, fiber, or pellet, supporting a membrane of the gas-absorbing material on a carrier, and filling the inside of a honeycomb-shaped structure with gas-absorbing powder. When the gas-absorbing material is formed into a sheet or membrane, its thickness is not particularly limited, but can be, for example, 1 to 10,000 μm, 10 to 5,000 μm, or 100 to 1,000 μm. When supporting a gas-absorbing material on a carrier, thin plates or fiber aggregates can be used as the carrier. The following describes thin plates and fiber aggregates that can be used as carriers.

[0061] [Thin plate] Thin plates can be flat plates, sheets, or foils with a thickness of, for example, 2 mm or less, or 5 μm or more. The thin sheet material has a constant-pressure specific heat of, for example, 2500 kJ / (m²). 3 Materials with a thermal conductivity of 10 W / (mK) or less may be used, or materials with a thermal conductivity of 10 W / (mK) or more may be used. Thin plates having such thermal properties respond well to changes in temperature in response to changes in the external temperature, and can efficiently transmit these temperature changes to the entire gas-absorbing material. In this specification, "specific heat at constant pressure" refers to a value measured by a calorimeter such as a hydrometer or differential scanning calorimeter. "Thermal conductivity" refers to a value measured by the laser flash method or the steady-state heat flow method.

[0062] As thin sheets, metal sheets (metal foils), sheets made of carbon materials, carbon sheets, resin films (polymer compound films), etc., can be used. Examples of sheets made of carbon materials include graphite sheets, and examples of resin films include polyethylene, polypropylene, PET, polyimide, etc. As thin sheets, aluminum sheets, iron sheets, graphite sheets, etc., may be used because of their high thermal conductivity. Alternatively, as thin sheets, aluminum sheets, graphite sheets, etc., may be used because of their low specific heat. Furthermore, as metal sheets, examples include stainless steel sheets, iron sheets, aluminum sheets, or nickel sheets, and among these, iron sheets, aluminum sheets, and nickel sheets may be particularly selected because of their relatively high thermal conductivity.

[0063] The thin plate may be a plate with a homogeneous internal structure, or it may be a porous material or a honeycomb structure. In the case of a porous material or honeycomb structure, the pores can be filled with gas-absorbing material, allowing heat from the thin plate to be easily transferred to the gas-absorbing material, thereby improving the responsiveness of the gas-absorbing material to temperature changes. In particular, porous materials such as foamed metal, foamed nickel, and porous carbon have high heat transfer properties to gas-absorbing materials, and by using them as carriers, the responsiveness of the gas-absorbing material to temperature changes can be greatly improved. The pore size of porous materials such as foamed metal can be, for example, 0.1 to 10 mm or 0.4 to 4 mm. The specific surface area can be, for example, 100 to 10000 m². 2 / m 3 , or 200-6000m 2 / m 3 This can be done. Furthermore, if a porous support made of porous resin or porous carbon is used as the porous support, the thermal efficiency of the absorber can be improved because the heat capacity is small. The porous material used as the support may be selected to have a porosity of, for example, 1 to 99%, 10 to 99%, or 20 to 95%. In this specification, "porosity of a sheet" means the porosity measured by the apparent volume and mass of the sheet and the density of the material. Furthermore, the carrier may be a laminate formed by stacking multiple of these thin plates. In the laminate, each thin plate may be the same, or multiple thin plates with different materials and thicknesses may be combined.

[0064] [Fiber aggregate] A fiber aggregate is made by processing a large number of fibers into a thin, wide plate. Examples of fiber aggregates include cloth and paper, and among these, porous materials such as filters are preferred. The cloth may be woven, felt, or nonwoven. Sintered metal fiber felt can also be used as a carrier. This material has a shape in which the fibers, which are sintered fibers, are densely aggregated, and high heat transfer properties can be obtained. For example, sintered felt made from stainless steel fibers or sintered felt made from nickel fibers can be used, and among these, sintered felt made from nickel fibers can be selected and used. The fibers used in the fiber aggregate have a constant-pressure specific heat of, for example, 2500 kJ / (m³). 3 Fibers with a thermal conductivity of 10 W / (mK) or less, or those with a thermal conductivity of 10 W / (mK) or more, may also be used. Fiber assemblies with such thermal properties respond well to changes in external temperature and can efficiently transmit these temperature changes throughout the gel-like film.

[0065] The fibers used in the fiber aggregate may be inorganic fibers, organic fibers, or composite fibers combining inorganic and organic fibers. Examples of inorganic fibers include stainless steel fibers, aluminum fibers, nickel fibers, and other metal fibers, as well as carbon fibers. Nickel fibers may be selected because they provide high heat transfer properties. Examples of organic fibers include natural fibers such as cotton and linen, and synthetic fibers such as rayon and polyester. The diameter of the fibers is not particularly limited, but for example, those with a diameter of 8 to 100 μm can be used. This makes it possible to obtain a gas-absorbing material film with excellent gas absorption and release properties. Furthermore, the carrier may be an aggregate formed by stacking multiple layers of these fiber aggregates. In the aggregate, each fiber aggregate may be identical, or multiple fiber aggregates with different fiber types, fiber diameters, fiber densities, etc., may be combined. Alternatively, the carrier may be a laminate formed by stacking thin plates and fiber aggregates.

[0066] The shape of the carrier is not particularly limited and can be selected as appropriate depending on the application. Specific examples of carrier shapes include plate-like and cylindrical shapes, and the planar shape of the plate and the cross-sectional shape of the cylinder may be any of the following: polygonal shapes such as squares and rectangles, circular shapes, elliptical shapes, etc. Gas-absorbing materials supported on a carrier can be formed by applying a slurry or powder of the gas-absorbing material to the surface of the carrier, or by bonding a pre-formed film of the gas-absorbing material to the surface of the carrier. A binder may be used to stably fix the slurry or powder of the gas-absorbing material to the carrier.

[0067] <Gas recovery device> As described above, the gas-absorbing material of the present invention can reversibly absorb acidic gases such as carbon dioxide and water vapor, and because its polymer component has low swelling properties, it can achieve a high volume filling rate when commercialized as a gas absorbent or the like. Therefore, it can be suitably used, for example, as a material for the gas absorber in a gas recovery device that selectively recovers carbon dioxide from exhaust gas. Below, a first and second embodiment of a gas recovery device to which the gas-absorbing material of the present invention is applied will be described. Figure 1 is a schematic diagram showing the gas recovery device of the first embodiment, and Figure 2 is a schematic diagram showing the gas recovery device of the second embodiment.

[0068] As shown in Figure 1, the gas recovery device of the first embodiment includes a heat exchanger 21, a desulfurizer 22, a cylindrical gas absorber 23, and first to third pipes 24, 25, and 26 connected to these parts. One end of the first pipe 24 is a gas inlet for introducing exhaust gas (gas to be treated), and the other end is connected to the desulfurizer 22. One end of the second pipe 25 is connected to the desulfurizer 22, and the other end is connected to one side of the gas absorber 23. The third pipe 26 has a circulation path 26a connected to, for example, one side and the other side of the gas absorber 23, and a branch path 26b that branches off from the circulation path 26a on one side of the gas absorber 23, with one end of the branch path 26b being a gas outlet for discharging the recovered carbon dioxide gas. Furthermore, the connecting portions of the second pipe 25 and the third pipe 26 on one side of the gas absorber 23 are, for example, provided on approximately the same diameter of a circular side surface, flanking the center. The heat exchanger 21 is connected to the middle section of the first pipe 24 and the middle section of the circulation path 26a, respectively. The gas absorber 23 is made of the gas absorbing material of the present invention, and when the gas recovery device is turned OFF, it is at a temperature similar to the ambient temperature. Furthermore, the gas absorber 23 can be formed in a filter shape and positioned so that it passes through at least a portion of the gas flow path in the gas recovery device. Furthermore, the gas absorber 23 can be positioned outside of at least a portion of the gas flow path in the gas recovery device, rather than being in the form of a filter.

[0069] To recover carbon dioxide from exhaust gas using this gas recovery device, the operation of each part is turned ON, and the collected high-temperature exhaust gas is introduced from one end of the first pipe 24. The introduced exhaust gas passes through the first pipe 24 and is introduced into a desulfurizer 22 that has a cooling capacity to about 30°C. Here, the desulfurizer and cooler may be separate devices. Also, the temperature of the gas after passing through the desulfurizer 22 with cooling capacity does not need to be 30°C, but may be around 40°C or 50°C. When passing through the first pipe 24, some of the heat of the exhaust gas is transferred to the circulation path 26a of the third pipe 26 via the heat exchanger 21, and the temperature is controlled so that the gas temperature or dew point temperature of the gas in the circulation path 26a is heated to about 60°C. Heating of the gas in the circulation path 26a may also be done by heating water. The gas temperature or dew point temperature in the circulation path 26a may be 60°C or higher, and may be around 75°C or 85°C. Also, the gas in the circulation path 26a may be under reduced pressure. If the gas in the circulation path 26a is under reduced pressure and the heating of the gas in the circulation path 26a is done by heated water, then there may be no gas flow in the circulation path 26a, or the gas flow rate may be extremely low. The exhaust gas introduced into the desulfurizer 22 undergoes desulfurization treatment in the desulfurizer 22 and then flows into the second pipe 25. The exhaust gas that flows into the second pipe 25 has a temperature or dew point temperature of about 30°C and is introduced into the gas absorber 23 at around this temperature. In the gas absorber 23, because the temperature of the exhaust gas is about 30°C, the absorber is cooled in the area in contact with the exhaust gas, and acidic gases such as carbon dioxide are efficiently absorbed by the gas absorbent material, while gases other than carbon dioxide are discharged to the outside of the gas absorber 23. If the dew point temperature of the exhaust gas is lower than the temperature of the absorbent material, the absorbent material and the exhaust gas are effectively cooled by the evaporation of moisture from the absorbent material, allowing for suitable temperature control. Furthermore, if the absorber is not sufficiently cooled by the cooled exhaust gas, additional cooling can be performed, such as by introducing a cooling gas, reducing the pressure, or using the latent heat of vaporization of water by introducing a dry gas. Meanwhile, the region of the gas absorber 23 that has absorbed carbon dioxide moves to the vicinity of the connection point of the third pipe 26 due to the rotation of the gas absorber 23, and comes into contact with the gas introduced from the circulation path 26a of the third pipe 26.The gas introduced from the circulation path 26a is heated to approximately 75°C through heat exchange with the exhaust gas. In the region of the gas absorber 23 that comes into contact with this gas, the gas absorbent material is heated, and acidic gases such as carbon dioxide are released. In this case, if the dew point temperature of the gas in the circulation path 26a is higher than the temperature of the absorbent material, the absorbent material is heated more effectively by the heat of condensation of water vapor, which is preferable. Also, even if the gas in the circulation path 26a is under reduced pressure, it is possible to effectively release carbon dioxide due to the decrease in the partial pressure of carbon dioxide. A portion of the released carbon dioxide flows into the branch path 26b of the third pipe 26 and is discharged to the outside from the gas outlet of the branch path 26b for recovery. Another portion of the released carbon dioxide flows into the circulation path 26a of the third pipe 26. The carbon dioxide that flows into the circulation path 26a is heated or humidified by the heat exchanger 21 along the way, and then reintroduced into the gas absorber 23, where the heat is used to heat the gas absorbent material.

[0070] As described above, in this first embodiment of the carbon dioxide gas recovery device, the heat from the exhaust gas is reused to heat the gas absorber and switch it from a state of absorbing acidic gas to a state of releasing it. In this embodiment, the heat from the exhaust gas is effectively utilized, so the energy consumption in the carbon dioxide gas separation and recovery process can be significantly reduced. In the first embodiment, if the temperature of the exhaust gas and the gas absorber cannot be controlled to a temperature suitable for carbon dioxide absorption and release, the temperature control is improved by adding an external heat exchange mechanism or an additional heating mechanism to the piping and absorber.

[0071] Next, a second embodiment of the gas recovery device will be described. As shown in Figure 2, the gas recovery apparatus of the second embodiment includes a first heat exchanger 31 and a second heat exchanger 32, a desulfurizer 33, a first tank 34 and a second tank 35, and a first pipe 36 and a second pipe 37 connected to these parts. One end of the first pipe 36 is a gas inlet for introducing exhaust gas (gas to be treated), and the other end is connected to the desulfurizer 33 which has a cooling capacity. Here, the desulfurizer and the cooler may be separate devices. The second pipe 37 has a main path 37a, one end of which is connected to the desulfurizer 33, and a first path 37b and a second path 37c that branch off from the other end of the main path 37a. One end of the first path 37b is in communication with the main path 37a, and the other end is connected to the first tank 34. One end of the second path 37c is in communication with the main path 37a, and the other end is connected to the second tank 35. Valves (not shown) for opening and closing each path 37b and 37c are provided near the other ends of the first path 37b and the second path 37c. The first heat exchanger 31 is connected to the first intermediate section of the first pipe 36 and the first tank 34, respectively, and the second heat exchanger 32 is connected to the second intermediate section of the first pipe 36 and the second tank 35, respectively. In the gas recovery device of the second embodiment, gas absorbing materials (gas absorbers) 38 and 39 are formed on the heat exchange surface of the first heat exchanger 31 in the first tank 34 and the heat exchange surface of the second heat exchanger 32 in the second tank 35, respectively, and when the gas recovery device is turned OFF, each gas absorber 38 and 39 is at a temperature similar to the ambient temperature (approximately 30°C).

[0072] To recover carbon dioxide gas from exhaust gas using this carbon dioxide gas recovery device, first, the valve of the first path 37b of the second pipe 37 is opened, the valve of the second path 37c of the second pipe 37 is closed, the first heat exchanger 31 is turned OFF, and the second heat exchanger 32 is turned ON. In this state, the first tank 34 functions as an absorption tower. That is, in this state, when the high-temperature exhaust gas after dust collection is introduced from one end of the first pipe 36, the introduced exhaust gas passes through the first pipe 36 and is introduced into the desulfurizer 33. As it passes through the first pipe 36, some of the heat of the exhaust gas is transferred to the second tank 35 via the second heat exchanger 32, and the exhaust gas is cooled. The exhaust gas introduced into the desulfurizer 33 undergoes desulfurization treatment in the desulfurizer 33, which has a cooling capacity, and after being further cooled, flows into the main path 37a of the second pipe 37. The temperature or dew point temperature of the exhaust gas flowing into the main path 37a is approximately 30°C, and at this temperature, it is introduced into the first tank 34 via the main path 37a and the first path 37b. Inside the first tank 34, the gas absorber 38 is efficiently cooled due to the exhaust gas temperature or dew point temperature of approximately 30°C, resulting in efficient absorption of carbon dioxide, while gases other than carbon dioxide are discharged to the outside through a gas outlet provided in the first tank 34. The temperature or dew point temperature of the exhaust gas flowing into the main path 37a and cooling the absorber does not necessarily have to be 30°C; it may be around 40°C or 50°C.

[0073] After the gas absorber 38 has sufficiently absorbed carbon dioxide, the valve of the first path 37b of the second pipe 37 is closed, the valve of the second path 37c of the second pipe 37 is opened, the first heat exchanger 31 is turned ON, and the second exchanger 32 is turned OFF. As a result, the heat from the exhaust gas passing through the first pipe 36 is transferred to the first tank 34 and the gas absorber 38 via the first heat exchanger 31. In the first heat exchanger 31, it is preferable to use water as the heat transfer medium and to heat the gas absorber 38 by introducing heated water or steam. The gas absorber 38 in the first tank 34 is heated to about 75°C by the heat from the first heat exchanger 31 and releases carbon dioxide. The temperature of the heated gas absorber 38 may be around 60°C or 85°C. Also, the gas absorber 38 may be under reduced pressure during heating. The released carbon dioxide is discharged and recovered from the gas outlet provided in the first tank 34. Meanwhile, exhaust gas at approximately 30°C, which flows into the second pipe 37 via the same route as described above, is introduced into the second tank 35 via the second path 37c, and carbon dioxide is absorbed by the gas absorber 39 loaded in the tank 35. When the dew point temperature of the exhaust gas is lower than the temperature of the absorber, the absorber and exhaust gas are effectively cooled by the evaporation of moisture from the absorber, which is preferable. Furthermore, if the cooling of the absorber by the cooled exhaust gas is insufficient, it is desirable to perform additional cooling such as introducing a cooling gas, reducing the pressure, or using the latent heat of vaporization of water by introducing a dry gas. In other words, in this state, the first tank 34 functions as a diffusion tower and the second tank 35 functions as an absorption tower, and the absorption and diffusion of carbon dioxide gas are carried out in parallel.

[0074] After sufficient release of carbon dioxide from gas absorber 38 and absorption of carbon dioxide by gas absorber 39, as shown in Figure 2, the valve of the first path 37b of the second pipe 37 is opened, the valve of the second path 37c of the second pipe 37 is closed, the first heat exchanger 31 is turned OFF, and the second heat exchanger 32 is turned ON, so that the first tank 34 functions as an absorption tower and the second tank 35 functions as a diffusion tower. As a result, carbon dioxide gas absorption and diffusion are carried out in parallel in the opposite towers compared to before the switch. Furthermore, by repeating the above switching operation, carbon dioxide gas absorption and diffusion from the exhaust gas can be carried out continuously, and carbon dioxide gas can be efficiently separated and recovered from a large amount of exhaust gas. The number of towers filled with gas absorbers may be two or more.

[0075] As described above, in this second embodiment of the gas recovery apparatus, the heat from the exhaust gas is reused to heat the gas absorber and switch from a state of absorbing acidic gas to a state of releasing it. Therefore, the energy utilization efficiency can be greatly increased compared to when using a conventional carbon dioxide gas separation and recovery process. In the second embodiment, if the temperature of the exhaust gas and absorber cannot be controlled to a temperature suitable for carbon dioxide absorption and release, the temperature control is improved by adding an external heat exchange mechanism or an additional heating mechanism to the piping and absorber. Gas recovery equipment can also be used for the purpose of supplying gas. When used for the purpose of supplying gas, it is provided as a gas supply device. [Examples]

[0076] The features of the present invention will be further described below with reference to examples and comparative examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. In the following description, the concentrations in parentheses indicate the concentration of the target component in the reaction mixture.

[0077] In this embodiment, the gas reversible absorption test was performed as follows. (CO2 reversible absorption test) The polymer sample was placed in a reactor, water was added, the reactor was sealed, and the reactor was moved into a 30°C constant temperature bath. Humidified 10% CO2 gas (CO2:N2=10:90) at 60°C was introduced into the reactor at a flow rate of 10 mL / min for 46 minutes to allow the polymer sample to absorb CO2. Subsequently, the temperature in the constant temperature bath was raised to 75°C and maintained for 25 minutes to allow the CO2 gas to dissipate. At this time, the amount of CO2 gas discharged from the reactor was measured and was determined as the reversible CO2 absorption amount of the polymer. In Examples 1-6 and Comparative Examples 1-8 below, 20 g of the polymer sample was placed in a 90 mL reactor, 40 mL of water was added, and measurements were taken.

[0078] [1] Examination of the total monomer concentration of the reaction mixture (Comparative Example 1) Production of a polymer with a total monomer concentration of 1.1 mol / L A mixture was prepared by dissolving N-(dimethylaminopropyl)methacrylamide (DMAPM: 5842.98 mg (6215.94 mL), 55 mol%), N,N'-methylenebisacrylamide (BIS: 962.02 mg, 10 mol%), and cetyltrimethylammonium bromide (CTAB: 36.445 mg, 2 mM) in Milli-Q water to a total volume of 50 mL. This mixture was heated to 70°C while stirring with a mechanical stirrer, and then a solution of N-tert-butylacrylamide (TBAm: 2779.80 mg, 35 mol%) dissolved in methanol (5 mL) was added, followed by nitrogen bubbling for 30 minutes. To this mixture, an acetone solution (250 μL) containing 2,2'-azobis(2-methylpropionitrile) (AIBN: 21.18 mg, 2.58 mM) was added to form a reaction mixture. Polymerization was carried out at 70°C for 3 hours under a nitrogen atmosphere to obtain a polymer precipitate. This reaction solution was filtered, and the filtered polymer was freeze-dried to obtain comparative sample 1.

[0079] (Comparative Example 2) Production of a polymer with a total monomer concentration of 0.57 mol / L A freeze-dried polymer (comparative sample 2) was obtained in the same manner as in Comparative Example 1, except that the amounts of DMAPM, TBAm, and BIS were changed as shown in Table 1.

[0080] (Example 1) Production of a polymer with a total monomer concentration of 1.7 mol / L A polymer precipitate was obtained in the same manner as in Comparative Example 1, except that the amounts of DMAPM, TBAm, and BIS were changed as shown in Table 1, and TBAm was dissolved in 8 mL of methanol and added to the mixture. 100 mL of MilliQ water was added to this polymer precipitate, and the mixture was pulverized with a hand blender to prepare a slurry. This slurry was filtered, and the filtered polymer was freeze-dried to obtain Sample 1.

[0081] (Example 2) Preparation of a polymer with a total monomer concentration of 2.4 mol / L In a flask containing BIS (4625.10 mg, 20 mol%) and CTAB (36.445 mg, 2 mM), DMAPM (14045.63 mg (14942.15 mL), 55 mol%) was added to dissolve a portion of the BIS, and then 30 mL of Milli-Q water was added. This mixture was heated to 70°C while stirring with a mechanical stirrer, and then a solution of TBAm (4773.00 mg, 25 mol%) dissolved in methanol (12 mL) was added, followed by nitrogen bubbling for 30 minutes. To this mixture, an acetone solution (250 μL) containing AIBN (21.18 mg, 2.58 mM) was added to form a reaction mixture, and polymerization was carried out at 70°C for 3 hours under a nitrogen atmosphere to obtain a polymer precipitate. After immersing this polymer precipitate in water overnight, the polymer was crushed with a hand mixer to obtain a slurry. The slurry was filtered, and the filtered polymer was freeze-dried to obtain sample 2.

[0082] (Comparative Example 3) Production of a polymer with a total monomer concentration of 0.31 mol / L The polymer was synthesized in the same manner as in Synthesis Example 1 of International Publication No. 2016 / 024633. Specifically, 1 liter of pure water was placed in a three-necked flask, heated to 70°C, and then 2 mM CTAB was added. Further, methanol solutions containing DMAPM (55 mol%), TBAm (43 mol%), and BIS (2 mol%) were added and dissolved to a total monomer concentration of 0.31 mol / L. This mixture was stirred with a mechanical stirrer while maintaining the temperature at 70°C, and nitrogen bubbling was performed for 1 hour. 5 mL of an aqueous solution containing 2,2'-azobis(2-methylpropionamidine) dihydrochloride (700 mg) was added to this mixture to form a reaction mixture, and polymerization was carried out under a nitrogen atmosphere at 70°C for 3 hours to obtain polymer particles with a particle size of 800 nm (comparative sample 3).

[0083] Table 1 shows the component amounts of the reaction mixture used for polymer synthesis for each example and comparative example. Note that in comparative example 3 in the table below, 2,2'-azobis(2-methylpropionamidine) dihydrochloride was used as the initiator (see * in the table).

[0084] [Table 1]

[0085] Table 2 shows the results of measuring the yield and reversible CO2 absorption for samples 1, 2, and comparative samples 1-3. Here, "yield" is the ratio (%) of the actual yield to the theoretical polymer yield calculated from the amount of each monomer used in the reaction mixture.

[0086] [Table 2]

[0087] As shown in Table 2, samples 1 and 2 exhibited superior reversible CO2 absorption, with sample 2 being the most superior. Furthermore, samples 1 and 2 showed significantly improved yields compared to comparative sample 3. Samples 1 and 2, and comparative samples 1 and 2, had equivalent yields. In other words, sample 2, with a higher total monomer concentration, achieved yields equivalent to those of sample 1, comparative samples 1 and 2, which had lower total monomer concentrations. This indicates that yields can be increased without increasing the size of the manufacturing container, demonstrating the industrial advantages of the manufacturing method of the present invention. Furthermore, when water was added to each sample and the water content was examined, it was shown that the water content was lowest in the order of sample 2, then sample 1, and then comparative samples 1, 2, and 3. Furthermore, a durability test was conducted on sample 2, involving 50 reversible gas absorption tests. The 50th test showed the same amount of reversible CO2 absorption as the first test, confirming that it possesses sufficient durability. Furthermore, as a variation of Sample 2, methanol without TBAm was added to the reaction mixture instead of the TBAm methanol solution, and a polymer sample was prepared with a DMAPM ratio of 80 mol%. When a CO2 reversible absorption test was performed, the amount of CO2 reversible absorption increased compared to Sample 2. Moreover, this CO2 reversible absorption amount was greater than that of the polymer sample prepared by adding water instead of methanol (polymer sample prepared using 100% water as the solvent). Furthermore, as another variation of Sample 2, when a polymer sample was prepared using dimethylaminopropylacrylamide (DMAPAAm) as the monofunctional monomer instead of DMAPM, results equivalent to those of Sample 2 were obtained.

[0088] [2] Investigation of the concentration of polyfunctional monomers and the effects of surfactants (Example 3) Production of polymers without using surfactant (CTAB) A freeze-dried polymer (Sample 3) was obtained in the same manner as in Example 1, except that CTAB was not added to the reaction mixture.

[0089] (Comparative Example 4) Production of a polymer in which the proportion of polyfunctional polymer (BIS) is 10 mol% A freeze-dried polymer (comparative sample 4) was obtained in the same manner as in Example 3, except that the proportion of TBAm among the monomers was changed to 35 mol% and the proportion of BIS to 10 mol%.

[0090] (Comparative Example 5) Production of a polymer in which the proportion of polyfunctional polymer (EGDMA) is 10 mol% A freeze-dried polymer (comparative sample 5) was obtained in the same manner as in Example 1, except that the proportion of TBAm among the monomers was changed to 35 mol%, and ethylene glycol dimethacrylate (EGDMA) was used instead of BIS, with its proportion set to 10 mol%.

[0091] Table 3 shows the component amounts of the reaction mixtures used in the polymer synthesis of the samples prepared in Example 3 and Comparative Examples 4 and 5. Note that in Comparative Example 5 (see * in the table below), EGDMA was used as a polyfunctional monomer.

[0092] [Table 3]

[0093] When water was added to Sample 1, prepared in Example 1, Sample 3, and Comparative Samples 4 and 5, both prepared in this example, Comparative Samples 4 and 5, which used 10 mol% of the polyfunctional monomer (BIS or EGDMA), all had high water content and swelled and became soft. However, Samples 1 and 3, which used 20 mol% of BIS, had relatively low water content and remained hard. This indicates that to obtain a polymer with a low degree of swelling, it is necessary to use a polyfunctional monomer at a ratio of 15 mol% or more. Furthermore, when comparing Sample 1, which used the surfactant (CTAB), with Sample 3, which did not use CTAB, a slight transparent phase was observed near the surface only in Sample 3. This indicates that it is preferable to add a surfactant to the reaction mixture to obtain a uniform polymer.

[0094] (Comparative Examples 6-8) Production of polymers with a polyfunctional polymer (BIS) content of 0-10 mol% and a total monomer concentration of 2.4 mol / L Lipo-dried polymers (comparative samples 6-8) were obtained in the same manner as in Example 2, except that the proportions of TBAm and BIS among the monomers were changed as shown in Table 4.

[0095] (Example 4) Production of a polymer with a polyfunctional polymer (BIS) content of 30 mol% and a total monomer concentration of 2.4 mol / L A freeze-dried polymer (Sample 4) was obtained in the same manner as in Example 2, except that the proportions of TBAm and BIS among the monomers were changed as shown in Table 4.

[0096] Table 4 shows the component amounts of the reaction mixtures used for polymer synthesis of the samples prepared in Comparative Examples 6-8 and Example 4, along with those of Sample 2 prepared in Example 2.

[0097] [Table 4]

[0098] When water was added to sample 2 prepared in Example 2 above, sample 4 prepared here, and comparative samples 6-8, comparative sample 6, which did not use polyfunctional monomer (BIS), and comparative samples 7 and 8, which had a BIS ratio of 5 mol% or 10 mol%, all had high water content and swelled and became soft. However, samples 2 and 4, which had a BIS ratio of 20 mol% or 30 mol%, did not swell and remained hard. Furthermore, the yield and reversible CO2 absorption were similar for comparative samples 7 and 8 and samples 2 and 4 (BIS concentration: 5-30 mol%). However, when polymer samples with a BIS concentration exceeding 30 mol% were also tested, a tendency for reversible CO2 absorption to decrease was observed. From this, it was shown that in order to obtain polymers with low water content and low swelling, it is necessary to use polyfunctional monomers at a ratio of 15 mol% or more, and in order to fully exhibit CO2 reversible absorption capacity, it is necessary to synthesize the polymer with polyfunctional monomers at a ratio of 30 mol% or less.

[0099] Here, as a variation of Sample 2, a polymer sample was prepared using 20 mol% EGDMA as a polyfunctional monomer instead of BIS, and a reversible CO2 absorption test was performed. The same amount of reversible CO2 absorption as Sample 2 was obtained. Furthermore, the polymer sample prepared using 20 mol% EGDMA had significantly smaller water content and swelling volume compared to the comparative samples with 5 mol% or 10 mol% EGDMA (about 1 / 3 of that with 10 mol% EGDMA, and less than 1 / 2 of that with 5 mol% EGDMA), and a remarkably large amount of reversible CO2 absorption was obtained (about 1.5 times that with 10 mol% EGDMA, and more than 2 times that with 5 mol% EGDMA).

[0100] [3] Examination of solvents (Examples 5 and 6) Production of polymers with a total monomer concentration of 3.0 mol / L Lipod-dried polymers (samples 5 and 6) were obtained in the same manner as in Example 2, except that the amount of MilliQ water added to the reaction mixture and the amount of methanol used to dissolve TBAm (amount of methanol added to the reaction mixture) were changed as shown in Table 5.

[0101] Table 5 shows the amounts of MilliQ water and methanol added to the reaction mixture in Examples 2, 5, and 6, and the reversible CO2 absorption amounts measured for samples 2, 5, and 6.

[0102] [Table 5]

[0103] In both Examples 5 and 6, the water content of the polymer was 0.7 g (H2O) / 1 g (water-containing polymer) or less, and good polymer materials with low water content were obtained. As shown in Table 5, sample 5, which had a reduced amount of solvent, showed a lower reversible CO2 absorption compared to sample 2. Furthermore, when the alcohol was removed from the solvent composition and only water was used, the reversible CO2 absorption decreased even further. From this, it was found that by drastically reducing the amount of solvent, the concentration of low-polarity monomers such as TBAm in the polymer increased during polymerization, making the local environment around the amine inside the gel extremely low-polarity, and the basicity of the amine decreased, resulting in a decrease in the reversible CO2 absorption. It was found that even if the monomer is a liquid, it is necessary to add a certain amount of solvent such as water or alcohol to the reaction mixture. In addition, since sample 5, which used methanol, showed a larger reversible CO2 absorption than sample 6, which did not use methanol, it was shown that it is preferable to use an alcohol such as methanol as a solvent. Furthermore, polymer samples were prepared and tested in the same manner as in Examples 2, 5, and 6, except that ethanol, isopropanol, butanol, or t-butanol were used instead of methanol. The results were equivalent to those obtained when methanol was used.

[0104] [4] Production of polymers by amine impregnation process (Example 7) Production of a polymer using DMAm (a monofunctional monomer without an amino group) as the monofunctional monomer and performing an amine impregnation step. A mixture was prepared by dissolving dimethylacrylamide (DMAm: 80 mol%), BIS (20 mol%), and CTAB (2 mM) in Milli-Q water to a total volume of 50 mL. This mixture was subjected to nitrogen bubbling for 30 minutes while increasing the temperature to 70°C. To this mixture, methanol (12 mL) that had also been subjected to nitrogen bubbling was added, followed by acetone solution (250 μL) containing AIBN (2.58 mM) to form a reaction mixture. Polymerization was carried out at 70°C for 3 hours under a nitrogen atmosphere to obtain a polymer precipitate. After allowing this polymer precipitate to stand overnight in water, the polymer (hydrated polymer) was recovered by grinding with a hand mixer and filtering. The water content of the recovered polymer was 0.6774 g (H2O) / 1 g (hydrated polymer). One g of the obtained polymer was weighed out and immersed in 2-(isopropylamino)ethanol (IPAE: 7490 μL) as an amine-containing treatment solution. This amine-containing treatment solution was slowly stirred overnight in a shaker to replace the water contained in the polymer with 8N IPAE, and then filtered to obtain a polymer material (sample 7) impregnated with IPAE.

[0105] (Example 8) Production of a polymer using NiPAm (a monofunctional monomer without an amino group) as the monofunctional monomer, by a step of swelling the polymer with an amine solution. A polymer material impregnated with 8N IPAE (Sample 8) was obtained in the same manner as in Example 7, except that N-isopropylacrylamide (NiPAm) was used instead of DMAm.

[0106] (Example 9) Production of a polymer using DMAPM (a monofunctional monomer having an amino group) and TBAm (a monofunctional monomer having a hydrophobic group) as monofunctional monomers, by a step of swelling the polymer with an amine solution. The polymer obtained in the same manner as in Example 2 was left to stand in water overnight, then pulverized with a hand mixer and filtered to recover the water-containing polymer. The water in this polymer was replaced with 8N IPAE using the same procedure as in Example 7 to obtain a polymer material (sample 9) impregnated with 8N IPAE.

[0107] (Example 10) Production of a polymer using DMAPM (a monofunctional monomer having an amino group) as the monofunctional monomer, by a step of swelling the polymer with an amine solution. A polymer material impregnated with 8N IPAE (Sample 10) was obtained in the same manner as in Example 9, except that methanol without TBAm was added to the reaction mixture instead of a methanol solution of TBAm, and the proportion of DMAPM was set to 80 mol%.

[0108] Table 6 shows the component amounts of the reaction mixtures used in the polymer synthesis of the samples prepared in Examples 7 to 10.

[0109] [Table 6]

[0110] The reversible CO2 absorption capacity of samples 7-10, swollen with amine solution, increased significantly compared to polymer samples prepared in the same manner except for swelling with water. Samples 7 and 8 absorbed approximately 3 times more CO2, sample 9 absorbed approximately 5 times more, and sample 10 absorbed approximately 2 times more. Furthermore, it was shown that the reversible gas absorption capacity could be further improved by improving the substitution ratio of water and IPAE.

[0111] [5] Manufacturing of sheets (Example 11) Manufacturing of a sheet using polymer The polymer precipitate synthesized in the same manner as in Example 2 was filtered and pulverized to obtain polymer powder. This polymer powder and polyethylene pellets were kneaded in a 1:2 mass ratio and subjected to biscrew extrusion molding. The strands were rolled out to a width of approximately 4 mm and cut to approximately 5 mm using a pelletizer to produce a sheet approximately 200 μm thick, 4 mm wide, and 5 mm long. A reversible gas absorption test was performed on this sheet, and a reversible CO2 absorption amount of 33 mL / g was obtained. From this, it was confirmed that the manufactured polymer also exhibits reversible gas absorption performance in sheet form.

[0112] [6] Investigation of polyfunctional monomer concentration and total monomer concentration (Comparative Example 9) Production of a polymer in which the proportion of polyfunctional monomer (BIS) is 5 mol% and the total monomer concentration is 2.3 mol / L Dimethylaminopropylacrylamide (DMAPAAm: 95 mol%) and BIS (5 mol%) were dissolved in Milli-Q water at 60°C to prepare a total volume of 30 mL aqueous solution. Ethanol was then added to prepare a mixture so that the total monomer concentration of the reaction mixture to be reacted in the next step was 2.3 mol / L. This mixture was heated to 70°C, and then nitrogen bubbling was performed with stirring for 30 to 60 minutes. To this mixture, a solution prepared by dissolving AIBN in a mixed solvent of acetone and water (AIBN concentration in the reaction mixture: 2.58 mM) was added to form the reaction mixture, and polymerization was carried out under a nitrogen stream at 70°C for 3 hours to obtain a polymer material (comparative sample 9).

[0113] (Comparative Example 10, Examples 11 and 12) Production of polymers with a polyfunctional monomer (BIS) content of 10 to 30 mol% and a total monomer concentration of 2.3 mol / L Polymer materials (comparative samples 10, 11, and 12) were obtained in the same manner as in Comparative Example 8, except that the proportions of DMAPAAm and BIS were changed as shown in Table 7.

[0114] (Examples 13-16) Production of polymers with a polyfunctional monomer (BIS) content of 20 mol% and a total monomer concentration of 0.54-2.3 mol / L. Polymer materials (samples 13-16) were obtained in the same manner as in Comparative Example 9, except that the reaction mixture was prepared so that the ratio of DMAPAAm and BIS was DMAPAAm:BIS = 80 mol%:20 mol%, resulting in the total monomer concentrations shown in Table 7.

[0115] Table 7 shows the monomer composition and total monomer concentration of the reaction mixture used in polymer synthesis for the samples prepared in Comparative Examples 9 and 10 and Examples 11 to 16, as well as the water content, swelling volume, and reversible CO2 absorption of the polymer material. In Table 7, "g (wet)" represents the weight of the polymer in a wet state, "mL (wet)" represents the volume of the polymer in a wet state, and "g / dry" represents the weight of the polymer in a dry state (in g or mL).

[0116] [Table 7]

[0117] Table 7 compares samples 9, 10, 11, and 12, which were prepared by varying the proportion of polyfunctional monomer (BIS) in the reaction mixture, with a total monomer concentration of 2.3 mol / L. Samples 11 and 12, with a BIS proportion between 10 mol% and 30 mol%, exhibit lower water content and swelling compared to samples 9 and 10, which had a BIS proportion of 10 mol% or less, indicating improved reversible CO2 absorption per unit volume. Furthermore, comparing samples 13-16, which were prepared by varying the total monomer concentration of the reaction mixture with a polyfunctional monomer proportion of 20 mol%, reveals that samples with higher total monomer concentrations exhibited lower water content and swelling, and greater reversible CO2 absorption per unit volume. This indicates that by setting the proportion of polyfunctional monomer within a predetermined range and further increasing the polymerization concentration (total monomer concentration of the reaction mixture), materials with greater reversible CO2 absorption per unit volume can be realized. These materials have the advantage of reducing the amount of heat required for temperature rise, as they can achieve sufficient reversible CO2 absorption even when used in relatively small volumes.

[0118] [7] Examination of the type of initiator (Example 17) Production of polymer using 2,2'-azobis(2,4-dimethylvaleronitrile) (V-65) as an initiator DMAPAAm (80 mol%), BIS (20 mol%), and MilliQ water were placed in a 5 L separable flask (first reactor) and immersed in a 50°C water bath, where the mixture was stirred. Ethanol was added to this mixture to adjust the volume so that the total monomer concentration of the reaction mixture to be reacted in the next step was 3 mol / L and the total volume was 3000 mL. This mixture was stirred at 100 rpm for 1 hour while bubbling with nitrogen, and then the first reactor was immersed in a 55°C water bath. After that, the water bath temperature was lowered to 45°C and the pressure inside the first reactor was reduced, and V-65 (2.58 mM) was added to the mixture as an initiator, and the reaction mixture was prepared by stirring at 240 rpm for 2 minutes. This reaction mixture was transferred to a stainless steel reactor (second reactor) using a tube, and the second reactor was immersed in a 55°C water bath and the reaction was carried out for 3 hours. After that, it was removed from the water bath and allowed to cool to obtain the polymer material (sample 17). The water content of sample 17 was 2.5 g (wet) / g (dry), and the reversible CO2 absorption was 69.5 mL / g (dry). V-65 is an initiator that starts the reaction at 47°C, and by using it, the polymerization reaction could be carried out at a relatively low temperature (55°C in this case). Furthermore, under similar conditions, polymer materials could be synthesized in the same way even when the polymerization reaction was carried out in a resin container (plastic bag). In addition, it is also possible to carry out the polymerization reaction while pouring the monomer solution (mixture) onto a conveyor belt.

[0119] [8] Investigation of the reversible absorption of CO2 by crushed polymer materials When the polymer materials synthesized in each of the above examples were ground using a meat chopper or a Fitzmill and the reversible CO2 absorption amount was measured, they showed similar reversible CO2 absorption amounts regardless of the grinding method.

[0120] [9] Investigation of the effects of adding fine particles to polymer materials (Examples 18, 19) Production of polymer material containing fine particles A polymer material was obtained in the same manner as in Comparative Example 9, except that the ratio of DMAPAAm to BIS was set to DMAPAAm:BIS = 85 mol%:15 mol%. The water content of this polymer material was 73.7% by weight. This polymer material was sequentially ground in a meat chopper at 1.5-bu (hole diameter 4.8 mm), 1.3-bu (hole diameter 4.0 mm), 1-bu (hole diameter 3.2 mm), 7-rin (hole diameter 2.4 mm), and 3-rin (hole diameter 1.1 mm) to obtain various polymer pulverized materials with different grinding degrees. To each polymer pulverized material, water-repellent silica RY300 (manufactured by Evonik: AEROSIL RY300, average primary particle size: 7 nm, water contact angle: 100° or more) was added in the blending ratios shown in Table 8 to produce polymer materials containing fine particles. The polymer material containing these fine particles was placed in a 250 mL plastic container, shaken, and then the surface was leveled and the height was measured. The results are shown in Table 8. Furthermore, Figure 3 shows the particle size distribution of the polymer material containing fine particles in which the proportion of water-repellent silica RY300 was 0.50% by volume. Figure 4 shows the amount of CO2 absorbed during the absorption process and the amount of CO2 released during the release process, measured by the pressure swing absorption method, for the polymer material containing fine particles (sample 18) in which water-repellent silica RY300 (0.50% by volume) was added to the polymer pulverized at 7 rin (sample 19). In Figures 3 and 4, "3 rin polymer" to "1.5 bu polymer" represent polymer pulverized at 3 rin to 1.5 bu, respectively, and "RY300" represents water-repellent silica RY300. The CO2 reversible absorption performance using the pressure swing absorption method was evaluated using the following procedure. First, the sample to be measured (10 L) contained in the reactor was placed in a constant temperature bath at a temperature of 40°C and a relative humidity of over 98% to humidify it sufficiently, and then the temperature was adjusted to 30°C. Next, a mixed gas of humidified CO2 and N2 (CO2 concentration: 10.03 vol%) was introduced into the sample at a flow rate of 1000 mL / min, and the CO2 concentration (A) of the gas discharged from the sample was measured using a multi-gas analyzer (Horiba VA-3000) (absorption process). Then, the gas introduced into the sample was switched to humidified N2 gas and introduced into the sample at a flow rate of 1000 mL / min, and the CO2 concentration (B) of the gas discharged from the sample was measured (desorption process). The reversible CO2 absorption performance of the sample under test was evaluated by using the cumulative difference between the CO2 concentration of the introduced mixed gas and the CO2 concentration measured during the absorption process (A) as the CO2 absorption amount, and the cumulative difference between the CO2 concentration measured during the emission process (B) as the CO2 emission amount. When the measured CO2 absorption amount is shown on a graph, a "-" sign may be added to the value to distinguish it from the CO2 emission amount, and it may be shown on the negative side of the vertical axis.

[0121] [Table 8]

[0122] As shown in Table 8, the bulk (filling amount) of the polymer material changed by varying the proportion of water-repellent silica RY300, and the bulk was smallest (largest filling amount) when the water-repellent silica RY300 was 0.50% by volume. Furthermore, as shown in Figure 4, the polymer material containing fine particles with a large filling amount (sample 18) showed a significant improvement in the reversible CO2 absorption per unit mass and the CO2 absorption / emission rate compared to the polymer pulverized material without water-repellent silica RY300 (sample 19). This indicates that by adding fine particles, the amount of polymer material packed can be increased, thereby improving the reversible CO2 absorption and CO2 absorption / release rate.

[0123]

[10] Investigation of the effects of pulverizing polymer materials containing fine particles (Example 20) Production of a fine particle-containing polymer pulverized material obtained by further grinding a fine particle-containing polymer material. From the polymer pulverized material prepared in Example 18, the pulverized material at 1.5 minutes of the meat chopper was mixed with water-repellent silica RY300 in a volume ratio of polymer pulverized material:water-repellent silica RY300 = 99.5:0.5 to obtain a fine particle-containing polymer material. This fine particle-containing polymer material was pulverized at 230 rpm using 5 mm diameter zirconia beads in a planetary ball mill (Fritsch: P-5) to obtain a pulverized material of the fine particle-containing polymer material (fine particle-containing polymer pulverized material, sample 20). When the particle size distribution of sample 20 was measured, it was confirmed that the majority of the pulverized material had a particle size of less than 100 μm. In addition, the moisture content of sample 20 was 72.45% by weight, and the moisture content of the polymer pulverized material contained in sample 19 was 73.17% by weight, which was slightly lower than the moisture content of the polymer material used (73.7% by weight).

[0124] Figure 5 shows the amount of CO2 absorbed during the absorption process, measured by the pressure swing absorption method, for sample 20 and sample 19 mentioned above. Here, 10 L of gas absorbent material was used as the sample to be measured, and measurements were performed with a mixed gas of CO2 and N2 and an N2 gas flow rate of 3000 mL / min. Figure 5 shows that the microparticle-containing polymer pulverized with a bead mill (sample 20) exhibits a dramatically improved CO2 absorption rate compared to the microparticle-containing polymer material that was not pulverized with a bead mill (sample 18). This indicates that increasing the degree of pulverization of the microparticle-containing polymer material can further enhance its reversible CO2 absorption performance.

[0125] The structures of the monomer, surfactant, and initiator used in this example are shown below.

[0126] [ka] JPEG2026050377000011.jpg125170 [Industrial applicability]

[0127] The manufacturing method of the present invention makes it possible to efficiently produce polymers with low water content yet high reversible gas absorption capacity. Therefore, by using the polymer of the present invention, it is possible to provide inexpensive gas absorption materials with high reversible CO2 absorption capacity and ease of handling. Thus, the present invention has high potential for industrial application. [Explanation of Symbols]

[0128] 21 Heat exchanger 22, 33 Desulfurizer 23 Gas absorber 24. First pipe 25 Second pipe 26 Third pipe 26a Circulation pathway 26b Branching Route 31 1st heat exchanger 32 Second heat exchanger 34 Tank No. 1 35 Tank No. 2 36 First pipe 37 Second pipe 37a Main route 37b Route 1 37c Second Route 38, 39 Gas absorbers

Claims

1. A gas absorbent material that is partly composed of a polymer material having the function of absorbing and releasing acidic gases, and having one of the following structures (1) to (5). (1) A structure in which the powder of the gas-absorbing material is filled inside a honeycomb-shaped structure. (2) A laminated structure of a sheet of the gas-absorbing material and a nonwoven fabric or mesh. (3) A structure in which the gas-absorbing material is filled inside the filter. (4) A structure in which the gas-absorbing material membrane is supported on a carrier. (5) A self-supporting membrane, fiber, or pellet formed by kneading the gas-absorbing material with a hard material.

2. A gas absorbent according to claim 1, satisfying the above (1).

3. The gas absorbent according to claim 2, wherein the honeycomb is formed of foamed metal or foamed nickel.

4. The gas absorbent material according to claim 2, wherein the honeycomb is formed of resin or carbon.

5. The gas absorbent material according to claim 2, wherein the pore diameter of the honeycomb is in the range of 0.1 to 10 mm.

6. The specific surface area of ​​the aforementioned honeycomb is 100 to 10,000 m². ２ / m ３ The gas absorbent according to claim 2, which is within the range.

7. The gas absorbent according to claim 1, satisfying the above (2).

8. A gas absorbent according to claim 1, satisfying the above (3).

9. A gas absorbent according to claim 1, satisfying the above (4).

10. The gas absorbent according to claim 1, satisfying the above (5).

11. The aforementioned polymer material A polymer comprising a monomer mixture consisting of a monofunctional monomer and a polyfunctional monomer in an amount of more than 10 mol% and less than or equal to 30 mol%, wherein the monofunctional monomer and the polyfunctional monomer are polymerized. The monofunctional monomer is selected from the group consisting of N-(aminoalkyl)acrylamide, N-(aminoalkyl)methacrylamide, aminoalkyl acrylate, and aminoalkyl methacrylate. The gas absorbent according to any one of claims 1 to 10, wherein the polyfunctional monomer is selected from the group consisting of polyfunctional (meth)acrylamide monomers and polyfunctional (meth)acrylate monomers.

12. The aforementioned polymer material A gas absorbent according to any one of claims 1 to 10, comprising a monomer mixture consisting of a monofunctional monomer without amino groups that do not constitute an amide structure and a polyfunctional monomer in an amount of more than 10 mol% and less than or equal to 30 mol%, wherein the polymer obtained by polymerizing the monofunctional monomer and the polyfunctional monomer is impregnated with an amine having a molecular weight of 61 to 10000.

13. A gas recovery apparatus comprising a gas absorbent according to any one of claims 1 to 12.

14. A gas recovery method comprising the step of recovering an acidic gas using a gas absorbent according to any one of claims 1 to 12.

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