Method for manufacturing porous structure, and porous structure

Abstract

A method for manufacturing a porous structure according to the present invention includes a step for removing a porogen from a resin structure by heating the resin structure, which contains a polymer and the porogen, wherein the porogen has a boiling point of 200°C or higher. The porous structure according to the present invention contains the porogen that has a boiling point of 200°C or higher.

Description

Method for manufacturing porous structure and porous structure

[0001] The present invention relates to a method for producing a porous structure and a porous structure.

[0002] In recent years, carbon capture and storage (CCS) and carbon capture and utilization (CCU) have been considered as a way to reduce the amount of carbon dioxide in the atmosphere. In CCS and CCU, carbon dioxide is sometimes captured by separating it from the atmosphere.

[0003] As a method for separating acidic gases such as carbon dioxide from the atmosphere, an adsorption method has been developed in which the acidic gas is adsorbed onto an adsorbent having a porous structure. The adsorbent used in the adsorption method can adsorb the acidic gas by, for example, contacting the atmosphere.

[0004] Examples of materials for the porous structure adsorbent include amine compounds that have the function of adsorbing acidic gases. For example, Patent Document 1 discloses an adsorbent prepared by polymerizing an amine-containing resin using an amine compound, an epoxy compound, and a porogen, and then extracting the porogen using a solvent.

[0005] International Publication No. 2021 / 246383

[0006] Conventional adsorbent manufacturing involves a cleaning step using a solvent, which leaves room for improvement in terms of environmental impact.

[0007] Therefore, an object of the present invention is to provide a method for producing a porous structure and a porous structure that reduces the environmental load.

[0008] The present invention provides a method for producing a porous structure, comprising a step of removing the porogen from a resin structure containing a polymer and a porogen by heating the resin structure, wherein the porogen has a boiling point of 200°C or higher.

[0009] The present invention further provides a porous structure comprising a porogen having a boiling point of 200°C or higher.

[0010] According to the present invention, it is possible to provide a porous structure and a method for producing the same that reduces the environmental load.

[0011] Fig. 1 is a diagram for explaining a method for measuring the amount of carbon dioxide adsorption and desorption rate by a porous structure. Fig. 2A is a perspective view schematically showing an example of a structure including a porous structure. Fig. 2B is a perspective view schematically showing a modified example of a structure including a porous structure.

[0012] A method for producing a porous structure according to a first aspect of the present invention includes a step of removing the porogen from a resin structure containing a polymer and a porogen by heating the resin structure, wherein the boiling point of the porogen is 200°C or higher.

[0013] In a second aspect of the present invention, for example, in the method for producing a porous structure according to the first aspect, the boiling point of the porogen is 350° C. or lower.

[0014] In a third aspect of the present invention, for example, in the method for producing a porous structure according to the first or second aspect, the porogen comprises at least one selected from the group consisting of (poly)alkyleneoxymonoalkyl ethers and (poly)alkyleneoxydialkyl ethers.

[0015] In a fourth aspect of the present invention, for example, in the method for producing a porous structure according to any one of the first to third aspects, the porogen comprises at least one selected from the group consisting of dimethoxytriethylene glycol, triethylene glycol butyl methyl ether, dimethoxytetraethylene glycol, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol-n-butyl ether, and tripropylene glycol dimethyl ether.

[0016] In a fifth aspect of the present invention, for example, in the method for producing a porous structure according to any one of the first to fourth aspects, the heating is carried out at 140° C. or lower.

[0017] In a sixth aspect of the present invention, for example, in the method for producing a porous structure according to any one of the first to fifth aspects, the polymer has an amino group.

[0018] In a seventh aspect of the present invention, for example, in the method for producing a porous structure according to any one of the first to sixth aspects, the polymer is an amine polymer containing constitutional units derived from epoxy monomers.

[0019] In an eighth aspect of the present invention, for example, the method for producing a porous structure according to any one of the first to seventh aspects further comprises a step of reacting a group of compounds including a compound C1 having an amino group and a compound C2 having an epoxy group with the porogen in a mixed solution, thereby obtaining the resin structure.

[0020] In a ninth aspect of the present invention, for example, in the method for producing a porous structure according to any one of the first to eighth aspects, the porous structure is an acidic gas adsorbent.

[0021] The porous structure according to the tenth aspect of the present invention contains a porogen having a boiling point of 200° C. or higher.

[0022] In an eleventh aspect of the present invention, for example, in the porous structure according to the tenth aspect, the boiling point of the porogen is 350° C. or less.

[0023] In a twelfth aspect of the present invention, for example, the porous structure according to the tenth or eleventh aspect has a specific surface area of ​​1.0 m 2 / g or more.

[0024] In a thirteenth aspect of the present invention, for example, in the porous structure according to any one of the tenth to twelfth aspects, the content of the porogen is 50 μg / g or more and 30,000 μg / g or less.

[0025] In a fourteenth aspect of the present invention, for example, the porous structure according to any one of the tenth to thirteenth aspects contains a polymer having an amino group as a main component.

[0026] In a fifteenth aspect of the present invention, for example, the porous structure according to any one of the tenth to fourteenth aspects is an acidic gas adsorbent.

[0027] In a sixteenth aspect of the present invention, for example, the porous structure according to any one of the tenth to fifteenth aspects has an adsorption amount a1 of 0.35 mmol / g or more when subjected to an adsorption test A1. Adsorption test A1: A mixed gas composed of carbon dioxide, nitrogen, and water vapor is continuously fed into a container containing the porous structure for 15 hours. Here, the carbon dioxide concentration in the mixed gas is 400 vol ppm, and the mixed gas is maintained at a temperature of 23°C and a humidity of 50% RH.

[0028] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0029] [Method for manufacturing a porous structure] The method for manufacturing a porous structure according to the first embodiment of the present invention includes a step of removing the porogen from a resin structure containing a polymer and a porogen by heating the resin structure. The porogen has a boiling point of 200°C or higher.

[0030] In this specification, "having a boiling point of 200°C or higher" means that the boiling point under atmospheric pressure (101.325 kPa) is 200°C or higher.

[0031] According to the above, a porous structure can be produced with reduced environmental impact.

[0032] The porogen is removed by, for example, volatilization by heating the resin structure. If the boiling point of the porogen is less than 200°C, the porogen will easily volatilize, making it impossible to maintain the resin structure and making it difficult to form a porous structure. That is, if the boiling point of the porogen is 200°C or higher, a porous structure can be formed. Note that, when the resin structure contains multiple types of porogens, it is sufficient that at least one of the porogens has a boiling point of 200°C or higher. When the resin structure contains multiple types of porogens, it is preferable that the boiling points of all of the porogens contained in the resin structure are 200°C or higher.

[0033] In this specification, "removing the porogen from the resin structure" refers to performing a process to remove the porogen from the resin structure, but does not mean completely removing all of the porogen from the resin structure. In other words, it is sufficient to obtain a porous structure, and the porogen does not necessarily have to be completely removed from the resin structure. For example, in the production method of the present invention, it is preferable to remove the porogen by the above-mentioned heating so that the porogen content in the porous structure obtained after the heat treatment is 30,000 μg / g or less. As described above, it is possible to produce a porous structure with reduced environmental impact while suppressing the complexity of the process and the scale of the production equipment. In addition, when the resin structure contains multiple types of porogens, it is preferable to remove the porogens so that the total content of all porogens in the porous structure obtained after the heat treatment is 30,000 μg / g or less.

[0034] The porous structure obtained by the production method of the present invention may be an acidic gas adsorbent. That is, in another aspect, the present invention can provide a method for producing an acidic gas adsorbent, comprising a step of heating a resin structure containing a polymer and a porogen to remove the porogen from the resin structure, wherein the porogen has a boiling point of 200° C. or higher.

[0035] The resin structure will be described in detail below.

[0036] The resin structure includes a polymer and a porogen. The resin structure is preferably a cured product in which the polymer and the porogen are phase-separated. In the cured product, a co-continuous structure is formed.

[0037] The porogen is, for example, a solvent that is phase-separated from the polymer in the resin structure. The porogen is preferably a solvent that can dissolve the monomers used in polymer synthesis and can cause reaction-induced phase separation after the polymer synthesis reaction.

[0038] The ratio of the porogens having a boiling point of 200° C. or higher to all the porogens contained in the resin structure is, for example, 50 wt % or higher, preferably 70 wt % or higher, more preferably 80 wt % or higher, even more preferably 90 wt % or higher, and particularly preferably 95 wt % or higher. The ratio of the porogens having a boiling point of 200° C. or higher to all the porogens contained in the resin structure is the ratio of the total weight of all the porogens having a boiling point of 200° C. or higher to the total weight of all the porogens contained in the resin structure.

[0039] The porogen preferably consists solely of a solvent having a boiling point of 200° C. or higher. That is, all the porogens contained in the resin structure preferably have a boiling point of 200° C. or higher.

[0040] The boiling point of the porogen is preferably 350°C or lower, more preferably 320°C or lower, even more preferably 300°C or lower, and particularly preferably 280°C or lower. The porogen preferably consists solely of a solvent having a boiling point of 200°C or higher and 350°C or lower. That is, all porogens contained in the resin structure preferably have boiling points of 200°C or higher and 350°C or lower. According to the above, the porogen can be removed from the resin structure while suppressing the complexity of the process and the scale of the production equipment. The boiling point of the porogen may be 210°C or higher.

[0041] The porogen preferably has an ether bond.

[0042] The porogen preferably includes at least one selected from the group consisting of (poly)alkyleneoxymonoalkyl ethers and (poly)alkyleneoxydialkyl ethers.

[0043] In this specification, (poly)alkyleneoxymonoalkyl ether means alkyleneoxymonoalkyl ether and polyalkyleneoxymonoalkyl ether, and (poly)alkyleneoxydialkyl ether means alkyleneoxydialkyl ether and polyalkyleneoxydialkyl ether.

[0044] The porogen may include a compound represented by the following formula (1):

[0045]

[0046] In formula (1), R 1 represents an alkyl group having 1 to 10 carbon atoms. 1 and L 2 are each independently an alkanediyl group having 1 to 10 carbon atoms. X is a hydrogen atom, a hydroxyl group, or OR 2 m represents a natural number from 1 to 5. 2 represents an alkyl group having 1 to 10 carbon atoms. 1 are independent of each other.

[0047] In formula (1), the number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4. The alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a s-butyl group, an isobutyl group, and a t-butyl group.

[0048] In formula (1), the number of carbon atoms in the alkanediyl group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. The alkanediyl group may be linear or branched. Examples of the alkanediyl group include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, and a propane-2,2-diyl group.

[0049] In formula (1), m is preferably a natural number of 1 to 3.

[0050] The porogen may include at least one selected from the group consisting of glycols and compounds in which the hydroxyl groups at one or both ends of a glycol or the hydrogen atoms of the hydroxyl groups are substituted with hydrocarbon groups (i.e., glycol ethers). Examples of glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. The hydrocarbon group may be an alkyl group. Examples of the alkyl group are as described above.

[0051] The porogen may include at least one selected from the group consisting of dimethoxytriethylene glycol, triethylene glycol butyl methyl ether, dimethoxytetraethylene glycol, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol-n-butyl ether, and tripropylene glycol dimethyl ether.

[0052] The porogen may be one selected from the above-mentioned compounds, or two or more selected from the above-mentioned compounds may be used in combination.

[0053] It is preferable that the porogen does not contain an ester, since esters are highly reactive with the amine-based monomers used in polymer synthesis and may inhibit the formation of the resin structure. Therefore, by not containing an ester, a stable resin structure can be formed.

[0054] The polymer may have an amino group.

[0055] The polymer may be, for example, an amine polymer containing structural units derived from an epoxy monomer. This amine polymer can be obtained, for example, by the reaction of a group of compounds containing an amine monomer and an epoxy monomer. Specifically, the amine polymer may be a polymer of a group of compounds containing an amine monomer and an epoxy monomer (particularly, a polymer of an amine monomer and an epoxy monomer).

[0056] The production method of the present invention may further include a step of reacting a compound group including a compound C1 having an amino group and a compound C2 having an epoxy group to obtain a polymer.

[0057] That is, the production method of the present invention may further include a step of reacting a compound group including a compound C1 having an amino group and a compound C2 having an epoxy group with a porogen in a mixed solution containing the compound group to obtain a resin structure containing a polymer and a porogen.

[0058] Each step of the production method of this embodiment will be described in detail below. Hereinafter, the step of obtaining a resin structure may be referred to as step (I). The step of removing the porogen from the resin structure by heating the resin structure may be referred to as step (II).

[0059] <Step I> As described above, the production method of the present invention may include, as an optional step, step (I) of reacting a compound group including a compound C1 having an amino group and a compound C2 having an epoxy group with a porogen in a mixed solution containing the compound group to obtain a resin structure containing a polymer and a porogen. Hereinafter, this mixed solution may be referred to as "mixed solution L."

[0060] In one preferred embodiment, the compound C1 includes, for example, an amine monomer.

[0061] The amine monomer is a monomer containing at least one amino group, for example, at least one primary amino group. The number of primary amino groups contained in the amine monomer is preferably 2 or more, may be 3 or more, or may be 4 or more. The upper limit of the number of primary amino groups is not particularly limited, and may be, for example, 100 or 10. The amine monomer may contain secondary amino groups or tertiary amino groups in addition to primary amino groups, but may not contain tertiary amino groups. In the amine monomer, the ratio of the number of primary amino groups to the number of all amino groups is not particularly limited, and may be, for example, 10% or more, preferably 20% or more, more preferably 30% or more, or may be 40% or more. The upper limit of this ratio is not particularly limited, and may be, for example, 80% or 60%.

[0062] The molecular weight of the amine monomer is not particularly limited and may be, for example, 50 or more, 100 or more, 150 or more, 200 or more, 300 or more, 500 or more, 1000 or more, or even 1500 or more. The upper limit of the molecular weight of the amine monomer is not particularly limited and may be, for example, 10000 or less, 5000 or less, 3000 or less, 1000 or less, or even 500 or less.

[0063] The amine equivalent of the amine monomer is, for example, 10 g / eq. or more, preferably 20 g / eq. or more, and more preferably 30 g / eq. or more. The larger the amine equivalent of the amine monomer, the easier it is to adjust the density of the nitrogen element in the polymer. The upper limit of the amine equivalent of the amine monomer is not particularly limited, and is, for example, 150 g / eq. or less, preferably 100 g / eq. or less, and may be 50 g / eq. or less. In this specification, the amine equivalent means the mass of the amine monomer relative to 1 equivalent of the active hydrogen of the primary amino group contained in the amine monomer.

[0064] Examples of the amine monomers include ethylamine, ethylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, tris(2-aminoethyl)amine, N,N'-bis(3-aminopropyl)ethylenediamine, polymethylenediamine, trimethylhexamethylenediamine, polyether Examples of the amine monomer include aliphatic amines such as butyldiamine; alicyclic amines such as isophoronediamine, menthanediamine, piperazine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro(5,5)undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, and modified products thereof; aliphatic polyamines such as polyethyleneimine and polyalkylenepolyamines; (meth)acrylic polymers having amino groups such as aminoethylated acrylic polymers; and aliphatic polyamidoamines formed by the reaction of polyamines with dimer acids. The amine monomer preferably includes an aliphatic amine, particularly triethylenetetramine (TETA), or an aliphatic polyamine, particularly polyethyleneimine (PEI). The amine monomers may be used alone or in combination of two or more.

[0065] Compound C2 includes, for example, an epoxy monomer.

[0066] The epoxy monomer contains at least one epoxy group. The number of epoxy groups contained in the epoxy monomer is preferably 2 or more, and may be 3 or more, or 4 or more. The upper limit of the number of epoxy groups contained in the epoxy monomer is not particularly limited and may be, for example, 100 or 10.

[0067] The molecular weight of the epoxy monomer is not particularly limited, and is, for example, less than 1,000, and preferably not more than 500. In some cases, the molecular weight of the epoxy monomer may be 1,000 to 50,000.

[0068] The epoxy equivalent of the epoxy monomer is not particularly limited and is, for example, 150 g / eq. or less, preferably 100 g / eq. or less. The smaller the epoxy equivalent of the epoxy monomer, the higher the density of nitrogen elements in the polymer tends to be. The lower limit of the epoxy equivalent of the epoxy monomer is not particularly limited and is, for example, 50 g / eq. Note that the epoxy equivalent means the mass of the epoxy monomer containing one equivalent of epoxy groups.

[0069] Examples of epoxy monomers include monofunctional epoxy compounds such as n-butyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and t-butylphenyl glycidyl ether; diepoxy alkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, and 1,9-decadiene diepoxide; (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, and ether group-containing polyfunctional epoxy compounds such as glycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol tetraglycidyl ether, glycerol polyglycidyl ether, and sorbitol polyglycidyl ether; and amino group-containing polyfunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0070] The epoxy monomer may be an aromatic epoxy resin, a non-aromatic epoxy resin, or the like. Examples of aromatic epoxy resins include polyphenyl-based epoxy resins, epoxy resins containing a fluorene ring, epoxy resins containing triglycidyl isocyanurate, and epoxy resins containing a heteroaromatic ring (e.g., a triazine ring). Examples of polyphenyl-based epoxy resins include bisphenol A-type epoxy resins, brominated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AD-type epoxy resins, stilbene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A novolac-type epoxy resins, cresol novolac-type epoxy resins, diaminodiphenylmethane-type epoxy resins, and tetrakis(hydroxyphenyl)ethane-based epoxy resins. Examples of non-aromatic epoxy resins include aliphatic glycidyl ether-type epoxy resins, aliphatic glycidyl ester-type epoxy resins, alicyclic glycidyl ether-type epoxy resins, alicyclic glycidyl amine-type epoxy resins, and alicyclic glycidyl ester-type epoxy resins. The epoxy monomers can be used alone or in combination of two or more.

[0071] The epoxy monomer preferably includes at least one selected from the group consisting of diepoxyalkanes, ether group-containing polyfunctional epoxy compounds, and amino group-containing polyfunctional epoxy compounds. As the epoxy monomer, diepoxyalkanes or ether group-containing polyfunctional epoxy compounds may be used in combination with amino group-containing polyfunctional epoxy compounds. Specific examples of preferred epoxy monomers include 1,7-octadiene diepoxide (ODE), ethylene glycol diglycidyl ether (EDE), pentaerythritol tetraglycidyl ether (PETG), 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-m-xylenediamine. When using a monofunctional epoxy compound, it is preferable to use it in combination with another epoxy monomer containing two or more epoxy groups. The monofunctional epoxy compound can also be used as a reactive diluent to adjust the viscosity of the mixed liquid L.

[0072] In the reaction of the compounds, the amino group of the amine monomer reacts with the epoxy group of the epoxy monomer. The reaction of the compounds can be carried out by applying energy to the compounds. The reaction of the compounds is, for example, a curing reaction, and the resulting resin structure is a cured body. The energy applied to the compounds is preferably thermal energy. However, the energy applied to the compounds may also be light energy.

[0073] Step (I) is carried out, for example, by the following method: First, the above-mentioned compounds are mixed with a porogen to prepare a mixed liquid L. The porogen is as described above.

[0074] Components other than the compound group may be further added to the mixed solution L. Examples of such components include a reaction accelerator. Examples of the reaction accelerator include tertiary amines such as triethylamine and tributylamine; and imidazoles such as 2-phenol-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenol-4,5-dihydroxyimidazole. These reaction accelerators can accelerate the reaction for synthesizing a polymer, for example.

[0075] Next, the compounds are reacted in the mixed liquid L. As an example, the mixed liquid L is filled into a mold and then subjected to a heat treatment to react the compounds. This results in a resin structure that is a cured body containing a polymer and a porogen. In this cured body, the polymer and the porogen undergo phase separation to form a co-continuous structure. Alternatively, the mixed liquid L may be brought into contact with a sheet-like substrate and then subjected to a heat treatment to react the compounds, thereby obtaining a sheet-like resin structure. The mixed liquid L may be brought into contact with the substrate by impregnating the substrate with the mixed liquid L, or by applying the mixed liquid L onto the substrate.

[0076] The heating temperature of the mixed liquid L is not particularly limited, but is preferably lower than the heating temperature of the resin structure in step (II) described below. The heating temperature of the mixed liquid L may be, for example, 40°C or higher and lower than 100°C, or 50°C or higher and 85°C or lower. The heating time of the mixed liquid L is not particularly limited, and is, for example, 1 minute to 5 hours. The mixed liquid L may be heated while being stirred. Here, it is preferable that the porogen hardly volatilizes due to heating for the reaction of the compound group. In other words, it is preferable that the compound C1 and the compound C2 in the mixed liquid L are completely reacted before the porogen is removed in step (II).

[0077] When the mixed liquid L is brought into contact with a sheet-shaped substrate and then subjected to heat treatment, the material of the substrate is not particularly limited, and examples thereof include ceramics such as cordierite, alumina, cordierite-α alumina, silicon nitride, zircon mullite, spodumene, alumina-silica magnesia, zircon silicate ester, sillimanite, magnesium silicate, zircon, petalite, and aluminosilicate; metals such as aluminum, titanium, stainless steel, Fe—Cr alloy, and Cr—Al—Fe alloy; polyolefin, polyester, polyurethane, polycarbonate, and polyether. Examples of the polymerizable compound include polyvinyl ether ketone, polyphenylene oxide, polyether sulfone, melamine, polyamide, poly(meth)acrylate, polystyrene, poly(meth)acrylonitrile, polyimide, polyfurfural alcohol, phenol furfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, poly(meth)acrylamide, epoxy resin, agar, agarose, cellulose, and other resins.

[0078] The substrate may or may not have a porous structure. Examples of substrates having a porous structure include fiber structures, foams, meshes, etc. Examples of substrates not having a porous structure include non-porous sheets, foils, etc.

[0079] Examples of fibers include glass fibers; natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. Examples of fiber structures include woven fabrics, nonwoven fabrics, and paper. A specific example of a fiber structure is glass paper.

[0080] The thickness of the substrate is not particularly limited and may be, for example, 1 μm to 500 μm, or 1 μm to 100 μm, or 100 μm to 300 μm.

[0081] The heating temperature of the mixed solution L does not need to be constant. For example, the temperature may be increased stepwise from 40° C. to cause the reaction of the compound group, and then the temperature may be continued to be increased up to a temperature at which the porogen is removed, thereby performing step (II) of removing the porogen from the resin structure successively to step (I).

[0082] <Step (II)> The production method of the present invention includes a step of removing the porogen from the resin structure by heating the resin structure containing a polymer and a porogen. When the production method of the present invention further includes step (I), the resin structure is the resin structure obtained in the above step (I).

[0083] From the viewpoint of suppressing decomposition and oxidation of the polymer, the resin structure is preferably heated to 140° C. or lower, more preferably 120° C. or lower. The resin structure is preferably heated to 100° C. or higher, more preferably 110° C. or higher. However, as long as the porogen can be removed, the heating temperature may be 80° C. or higher, or 90° C. or higher.

[0084] When the production method of the present invention further includes step (I), the heating temperature of the resin structure in step (II) is preferably higher than that in the above-mentioned step (I).

[0085] The heating time is not particularly limited, but is preferably a time sufficient for the porogen to be removed. The heating time for the resin structure is preferably from 3 minutes to 15 hours, more preferably from 1 hour to 10 hours.

[0086] The resin structure may be heated in a reduced pressure atmosphere or a vacuum atmosphere.

[0087] The resin structure may be heated in one step or in two or more steps. At least one of the heating temperature, heating time, and environment may be different in each step. For example, a first heating step may be performed for a short time, followed by a second heating step for a long time under different temperature conditions or in a different environment. For example, the resin structure may be first heated at 100°C to 120°C for 2 to 10 minutes, followed by a second heating step for 1 to 6 hours at 80°C to 120°C in a vacuum environment. The first heating step may be performed consecutively with step (I).

[0088] As described above, in step (II), it is preferable that the porogen is removed by the heat treatment of the resin structure so that the porogen content in the porous structure obtained after the heat treatment is 30,000 μg / g or less.

[0089] As described above, step (I) and step (II) may be carried out consecutively.

[0090] The production method of the present invention preferably does not include any other operation between step (I) and step (II). Such an operation is, for example, solvent extraction. That is, in the production method of the present invention, removal of the porogen by solvent extraction is preferably not performed. In the present invention, removal of the porogen from the resin structure is more preferably performed only by volatilizing the porogen by heating the resin structure. However, a reduced pressure operation or a vacuum operation for volatilizing the porogen is not excluded.

[0091] In the production method of the present invention, it is preferable to remove the porogen from the resin structure by heating without performing solvent extraction, which eliminates the need for exposure to an extracting solvent and washing, thereby reducing the environmental impact.

[0092] The porous structure obtained by the production method according to the first embodiment of the present invention may have a porous structure containing pores derived from a three-dimensional network skeleton, and the three-dimensional network skeleton may contain a polymer having an amino group.

[0093] [Porous Structure] The porous structure according to the second embodiment of the present invention contains a porogen having a boiling point of 200° C. or higher.

[0094] In this specification, the phrase "the porous structure contains a porogen (having a boiling point of 200° C. or higher)" includes an embodiment in which the porogen (having a boiling point of 200° C. or higher) is present in the pores of the porous structure.

[0095] The shape of the porous structure is not particularly limited and may be, for example, a block shape, a sheet shape, a particulate shape, etc. In this specification, particulate shape includes spherical shape, ellipsoidal shape, scale shape, fibrous shape, etc.

[0096] In the porous structure according to the second embodiment, the porous structure may include pores derived from the three-dimensional network skeleton. The three-dimensional network skeleton may include a polymer having an amino group. Hereinafter, the polymer having an amino group may be referred to as "polymer P." Details of polymer P will be described later. The porous structure according to the second embodiment may include polymer P as a main component. In this specification, "main component" means the component that is contained in the largest amount by weight.

[0097] The porous structure according to the second embodiment includes, for example, a porous body S containing a polymer P and a porogen. For example, in the porous structure, the porogen is present in the pores contained in the porous body S. The porous body S has the function of adsorbing acidic gases due to amino groups. The porous body S is typically composed only of the polymer P. The porous structure according to the second embodiment is, for example, an acidic gas adsorbent.

[0098] The shape of the porous body S is, for example, a block shape, a sheet shape, a particle shape, etc. The porous structure may include a porous resin sheet as the porous body S, but may not include a porous resin sheet.

[0099] The porous structure according to the second embodiment may further include, for example, a substrate. The substrate supports the porous body S and is in direct contact with the porous body S, for example.

[0100] The porous structure according to the second embodiment may not include any member other than the porous body S, such as a substrate, and may be composed only of the porous body S. When the porous structure does not include a substrate or the like, the shape of the porous structure tends to be easily adjusted by cutting or machining.

[0101] The porous structure according to the second embodiment may be a sheet-like structure. The porous structure as a sheet-like structure has, for example, a flat plate shape or a corrugated shape.

[0102] The specific surface area of ​​the porous structure (porous body S) is not particularly limited, and is, for example, 0.5 m 2 / g or more, and 1.0m 2 / g or more, 2.0m 2 / g or more, 3.0m 2 / g or more, 4.0m 2 / g or more, 5.0m 2 / g or more, 6.0m 2 / g or more, 7.0m 2 / g or more, 8.0m 2 / g or more, and even 9.0m 2 / g or more. The larger the specific surface area of ​​the porous structure, the faster the rate at which the porous structure adsorbs acidic gases tends to increase. The upper limit of the specific surface area of ​​the porous structure is not particularly limited, and may be, for example, 100 m 2 / g. The specific surface area of ​​the porous structure means the Brunauer-Emmett-Teller (BET) specific surface area measured by nitrogen gas adsorption. The specific surface area of ​​the porous structure can be measured by a method conforming to the provisions of JIS Z8830:2013.

[0103] The porous structure according to the second embodiment may have an adsorption amount a1 of carbon dioxide of 0.35 mmol / g or more when subjected to the following adsorption test A1. Adsorption test A1: A mixed gas composed of carbon dioxide, nitrogen, and water vapor is continuously fed into a container containing the porous structure for 15 hours. Here, the carbon dioxide concentration in the mixed gas is 400 vol ppm, and the mixed gas is kept at a temperature of 20°C and a humidity of 50% RH.

[0104] The porous structure according to the second embodiment may have a carbon dioxide desorption amount b1 of 0.2 mmol / g or more when subjected to the following adsorption test B1: Desorption test B1: While continuing to feed the mixed gas into the container, the porous structure after adsorption test A1 is heated at 50°C for 15 hours.

[0105] The details of the adsorption test A1 and the desorption test B1 will be described later.

[0106] Each component of the porous structure according to the second embodiment will be described in detail below.

[0107] (Porogen) Examples of porogens include those described above in the first embodiment. The porous structure may contain one or more porogens selected from those described above. When the porous structure contains multiple types of porogens, it is sufficient that the boiling point of at least one porogen is 200°C or higher. When the porous structure contains multiple types of porogens, it is preferable that the boiling points of all porogens contained in the porous structure are 200°C or higher. The boiling points of the porogens are preferably 350°C or lower, more preferably 320°C or lower, even more preferably 300°C or lower, and particularly preferably 280°C or lower. It is preferable that the boiling points of all porogens contained in the porous structure are 200°C or higher and 350°C or lower. The boiling points of the porogens may be 210°C or higher.

[0108] The upper limit of the porogen content in the porous structure is preferably 30,000 μg / g or less, more preferably 20,000 μg / g or less, even more preferably 10,000 μg / g or less, particularly preferably 9,000 μg / g or less, and most preferably 8,000 μg / g or less. The porogen content is, for example, 50 μg / g or more and 30,000 μg / g or less relative to the porous structure. The lower limit of the porogen content may be 100 μg or more or 200 μg / g or more. Such a porous structure can be produced with a reduced environmental impact while minimizing the complexity of the production process and the scale of the production equipment. Therefore, the porous structure of the present invention can be mass-produced with a reduced environmental impact. When the porous structure contains multiple types of porogens, the total content of all porogens is preferably 30,000 μg / g or less, more preferably 20,000 μg / g or less, even more preferably 10,000 μg / g or less, particularly preferably 9,000 μg / g or less, and most preferably 8,000 μg / g or less, relative to the porous structure. In some cases, the porogen content may be 30 μg / g or less, or 10 μg / g or less, relative to the porous structure. Furthermore, when the porous structure contains multiple types of porogens, the total content of all porogens may be 30 μg / g or less, or 10 μg / g or less, or the porous structure may not contain any porogens. However, in this case, a high-temperature heat treatment may be required in the manufacturing process of the porous structure, which may cause discoloration such as yellowing.

[0109] The porogen content in the porous structure can be measured, for example, by liquid chromatography mass spectrometry (LC / MS).

[0110] (Porous body S) The porous body S contains, for example, a polymer P as a main component. The content of the polymer P in the porous body S is, for example, 50 wt % or more, preferably 70 wt % or more, more preferably 90 wt % or more, and may be 95 wt % or more, or may be 99 wt % or more. The porous body S may be composed essentially of only the polymer P. The higher the content of the polymer P, the more the porous structure tends to improve its ability to adsorb acidic gases.

[0111] The density d of the nitrogen element in the porous body S is not particularly limited and is, for example, 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The larger the density d of the nitrogen element, the greater the amount of acidic gas adsorbed by the porous structure and the rate at which the acidic gas is adsorbed. The upper limit of the density d of the nitrogen element is not particularly limited and may be, for example, 30 mmol / g or 20 mmol / g. In this specification, the density d of the nitrogen element in the porous body S means the amount of nitrogen element contained in 1 g of the porous body S. Note that when all of the nitrogen elements contained in the porous body S are derived from amino groups, the density d of the nitrogen element can be regarded as the density of the amino groups in the porous body S.

[0112] The porous body S may be composed substantially only of the polymer P, but the porous body S may also contain other materials in addition to the polymer P. Examples of other materials include reaction accelerators, plasticizers, fillers, pigments, dyes, antioxidants, conductive materials, antistatic agents, UV absorbers, flame retardants, and antioxidants. Examples of reaction accelerators include those described above in the first embodiment. It is preferable that the porous body S does not contain, for example, other components such as porous particles such as alumina or a binder for binding the porous particles together.

[0113] Examples of fillers include fibers and fiber structures containing fibers. Examples of fibers include glass fibers; natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. Examples of fiber structures include woven fabrics, nonwoven fabrics, and paper. A specific example of a fiber structure is glass paper.

[0114] The porous body S may have a porous structure including pores derived from the three-dimensional network skeleton. The three-dimensional network skeleton is typically composed only of the polymer P. In the porous body S, for example, the three-dimensional network skeleton extends continuously. The pores contained in the porous body S are, for example, continuous pores formed continuously in a three-dimensional manner. The porous body S may have closed pores or may have through holes penetrating the porous body S. When the porous body S contains a fibrous structure as a filler, the porous structure of the porous body S may further have pores derived from the fibrous structure. Note that the porous body S preferably does not contain, for example, fibers containing the polymer P, and is preferably not a nonwoven fabric containing such fibers. That is, in the second embodiment, the porous body S excludes, for example, nonwoven fabrics having fibers containing the polymer P.

[0115] When the porous body S contains a fibrous structure as a filler, the three-dimensional network skeleton containing the polymer P and the fibrous structure may exist independently in the porous body S. In this case, the porous structure of the porous body S has, for example, pores derived from the three-dimensional network skeleton containing the polymer P and further pores derived from the fibrous structure. In this case, the porous body S can be considered to be a composite of the three-dimensional network skeleton containing the polymer P and the fibrous structure.

[0116] The porosity of the porous body S is, for example, 20% or more, preferably 30% or more, and more preferably 40% or more. The upper limit of the porosity of the porous body S is not particularly limited, and may be, for example, 80% or 60%. The porosity of the porous body S is determined by the volume V (cm 3 ), weight W (g) and true density D (g / cm 3 The true density D means the specific gravity of the material that constitutes the porous body S. Porosity (%) = 100 × (V - (W / D)) / V

[0117] (Polymer P) The polymer P contains, for example, at least one amino group selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group. From the viewpoint of acidic gas adsorption, the polymer P preferably contains at least one selected from the group consisting of a primary amino group and a secondary amino group, and particularly preferably contains a secondary amino group. In other words, the amino group possessed by the polymer P preferably contains a secondary amino group. The polymer P having a secondary amino group also tends to easily desorb the adsorbed acidic gas. In other words, the polymer P having a secondary amino group can be used as an acidic gas adsorbent under relatively mild conditions for regeneration treatment of the porous structure. The polymer P may contain a tertiary amino group, but it does not have to contain a tertiary amino group.

[0118] The weight ratio of nitrogen elements in polymer P is, for example, 5 wt % or more, preferably 10 wt % or more. The higher this weight ratio, the more the porous structure tends to improve its ability to adsorb acidic gases. The upper limit of the weight ratio of nitrogen elements in polymer P is not particularly limited, and is, for example, 30 wt %. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the weight ratio of nitrogen elements described above can be considered to be the weight ratio of amino groups in polymer P.

[0119] The density of nitrogen elements in polymer P is, for example, 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The upper limit of the density of amino groups is not particularly limited and is, for example, 30 mmol / g. In this specification, the density of nitrogen elements in polymer P means the amount of amino groups contained in 1 g of polymer P. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the density of nitrogen elements can be considered to be the density of amino groups in polymer P.

[0120] The polymer P may contain a functional group other than an amino group. Examples of the functional group include a hydroxyl group, an ether group, an ester group, and an amide group. The polymer P preferably contains an ether group as the functional group.

[0121] The polymer P is, for example, an amine polymer containing a structural unit U1 derived from an epoxy monomer. This amine polymer can be obtained, for example, by the reaction of a group of compounds containing an amine monomer and an epoxy monomer. Specifically, the polymer P may be a polymer of a group of compounds containing an amine monomer and an epoxy monomer (particularly a polymer of an amine monomer and an epoxy monomer). The polymer tends to have a high nitrogen density and also high heat resistance and moist heat resistance.

[0122] Examples of the amine monomer include those described above in the first embodiment. Examples of the epoxy monomer include those described above in the first embodiment.

[0123] As described above, polymer P as an amine polymer contains a structural unit U1 derived from an epoxy monomer. When polymer P is a polymer, polymer P further contains a structural unit U2 derived from an amine monomer. The content of structural unit U1 in polymer P, particularly in polymers, is, for example, 20 wt % to 70 wt %. The content of structural unit U2 in polymer P, particularly in polymers, is, for example, 30 wt % or more, preferably 50 wt % or more. The upper limit of the content of structural unit U2 is not particularly limited, and is, for example, 80 wt %.

[0124] The glass transition temperature Tg of the polymer P is not particularly limited, and is, for example, 40°C or lower, preferably 30°C or lower, more preferably 20°C or lower, and even more preferably 15°C or lower, and may be 10°C or lower, 5°C or lower, or 0°C or lower. When the glass transition temperature Tg of the polymer P is low to this extent, the rate at which the acidic gas is adsorbed in the porous structure tends to be high. The lower limit of the glass transition temperature Tg of the polymer P is, for example, -100°C, preferably -50°C, and more preferably -10°C, from the viewpoint of sufficiently ensuring the adsorption and desorption properties of the acidic gas and from the viewpoint of heat resistance. In this specification, the glass transition temperature Tg is the midpoint glass transition temperature (T mgThe polymer P generally corresponds to a thermosetting resin. The polymer P is solid at, for example, 25°C, preferably in the range of 25°C to 80°C.

[0125] The weight average molecular weight of the polymer P is not particularly limited and is, for example, 500 or more, preferably 1000 or more, more preferably 10000 or more, and even more preferably 100000 or more. The upper limit of the weight average molecular weight of the polymer P is, for example, 10,000,000.

[0126] (Substrate) Examples of the substrate include those described above as the substrate in the first embodiment.

[0127] <Adsorption Test and Desorption Test> The following describes the details of the adsorption test A1 and the desorption test B1. The adsorption test A1 and the desorption test B1 can be performed using, for example, the measurement device 100 shown in FIG. 1 . The measurement device 100 includes a first tank 30 and a second tank 31. As an example, the first tank 30 stores dry nitrogen, and the second tank 31 stores a mixed gas of dry nitrogen and dry carbon dioxide. The concentration of carbon dioxide in the mixed gas in the second tank 31 is, for example, 5 vol %.

[0128] The measuring device 100 further includes a first container 40 containing water 70, and a first path 60 for sending nitrogen from the first tank 30 to the first container 40. The first path 60 has one end connected to a gas outlet of the first tank 30 and the other end disposed in the water 70 of the first container 40. The nitrogen sent from the first tank 30 to the first container 40 is humidified by contact with the water 70. A mass flow controller 35 is disposed in the first path 60 for adjusting the flow rate of nitrogen sent from the first tank 30 to the first container 40.

[0129] The measuring apparatus 100 further includes a second container 41, a second path 62, and a bypass path 61. The second path 62 connects the first container 40 and the second container 41. The humidified nitrogen sent to the first container 40 is sent to the second container 41 through the second path 62. The bypass path 61 branches off from the first path 60 at a position between the first tank 30 and the mass flow controller 35 and connects to the second path 62. A portion of the nitrogen sent from the first tank 30 flows into the bypass path 61 and is sent to the second container 41 through the second path 62. A mass flow controller 36 is disposed in the bypass path 61 to adjust the flow rate of nitrogen sent from the first tank 30 to the bypass path 61.

[0130] The measuring device 100 further includes a third path 63 for sending the mixed gas from the second tank 31 to the second path 62. The third path 63 has one end connected to the gas outlet of the second tank 31 and the other end connected to the second path 62. A mass flow controller 37 is disposed in the third path 63 for adjusting the flow rate of the mixed gas sent from the second tank 31 to the second path 62. The mixed gas sent to the second path 62 is sent to the second container 41 through the second path 62.

[0131] The measuring device 100 further includes a third container 42 and a fourth path 64. The third container 42 contains water 71 and an adsorption unit 21 disposed in the water 71. In the third container 42, the temperature of the water 71 is maintained at 23°C. The adsorption unit 21 has a gas inlet 22 and a gas outlet 23. The adsorption unit 21 functions as a container that contains a porous structure (acid gas adsorbent) therein. The adsorption unit 21 is configured to prevent the water 71 from penetrating into the interior. The adsorption unit 21 is typically a tube made of a hydrophobic resin, for example, a fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). As an example, the tube serving as the adsorption unit 21 has an inner diameter of 4 mm and an outer diameter of 6 mm. The adsorption unit 21 is configured to be detachable from the measuring device 100.

[0132] The measuring device 100 can also be used as an acid gas adsorption device equipped with the adsorption section 21 .

[0133] The fourth path 64 connects the second container 41 and the third container 42. Specifically, the fourth path 64 is connected to the gas inlet 22 of the adsorption unit 21 in the third container 42. A first concentration meter 50 is disposed in the fourth path 64 to measure the concentration of carbon dioxide in the gas supplied to the adsorption unit 21. As the first concentration meter 50, for example, a CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used.

[0134] The measuring device 100 further includes a fifth path 65 connected to the gas outlet 23 of the adsorption unit 21 for discharging gas from the adsorption unit 21 to the outside of the measuring device 100. A back pressure valve 55 and a second concentration meter 51 are disposed in the fifth path 65. The back pressure valve 55 allows the pressure inside the adsorption unit 21 to be adjusted to a constant value. The second concentration meter 51 can measure the concentration of carbon dioxide in the gas discharged from the adsorption unit 21. For example, a CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used as the second concentration meter 51.

[0135] Each path of the measuring device 100 is made up of, for example, a metal or resin pipe.

[0136] (Pretreatment) First, a porous structure is prepared and dried. The drying treatment is performed, for example, by treating the porous structure in a vacuum atmosphere at 60°C for two hours or more. Next, the dried porous structure is packed into the adsorption unit 21 in a dry room with a dew point of approximately -60°C. The weight of the porous structure packed into the adsorption unit 21 is, for example, 50 mg. Next, the fourth path 64 and the fifth path 65 are connected to both ends of the adsorption unit 21, and the adsorption unit 21 is immersed in water 71 in the third container 42.

[0137] Next, nitrogen from the first tank 30 and the mixed gas from the second tank 31 are supplied to the second container 41 via the first path 60, the second path 62, the bypass path 61, and the third path 63 of the measuring device 100. These gases are mixed in the second container 41 to obtain a mixed gas G composed of carbon dioxide, nitrogen, and water vapor. In the second container 41, the carbon dioxide concentration in the mixed gas G is adjusted to 400 vol ppm. The mixed gas G has a temperature of 23°C and a humidity of 50% RH. The mixed gas G is supplied to the adsorption unit 21 via the fourth path 64 at a flow rate sufficient for the weight of the porous structure, for example, a flow rate of 300 mL / min for a 50 mg porous structure. In the adsorption unit 21, the pressure of the mixed gas G is adjusted to, for example, 107 kPa by the back pressure valve 55.

[0138] Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the third container 42 and immersed in a water bath (not shown) at 80°C for two hours or more. The adsorption unit 21 is immersed in the water bath until the carbon dioxide concentration measured by the first concentration meter 50 and the carbon dioxide concentration measured by the second concentration meter 51 become substantially the same value. This completes the pretreatment of the porous structure in the adsorption unit 21.

[0139] (Adsorption Test) Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the hot water bath and immersed in the water 71 in the third container 42. This starts a carbon dioxide adsorption test (adsorption test A1) for the porous structure in the adsorption unit 21. The adsorption test is carried out for 15 hours after it has started. More specifically, the mixed gas G is continuously supplied to the adsorption unit 21 for 15 hours. When the adsorption test has been carried out for 15 hours, it can generally be considered that the adsorption of carbon dioxide by the porous structure has reached equilibrium.

[0140] In adsorption test A1, the amount of carbon dioxide adsorbed by the porous structure from the start to 15 hours is measured as M1. The amount of carbon dioxide adsorbed by the porous structure can be calculated from the results of measuring the difference over time between the carbon dioxide concentration measured by first concentration meter 50 and the carbon dioxide concentration measured by second concentration meter 51. Based on the amount of substance M1, the amount of carbon dioxide adsorbed by 1 g of the porous structure in 15 hours is calculated, and the calculated value is specified as the adsorption amount a1.

[0141] (Desorption Test) Next, while the mixed gas G continues to be supplied to the adsorption unit 21, the adsorption unit 21 is removed from the third container 42 and immersed in a water bath (not shown) at 50°C. This starts a carbon dioxide desorption test (desorption test B1) for the porous structure in the adsorption unit 21. The desorption test is continued for 1.5 hours after the start.

[0142] In desorption test B1, the amount of carbon dioxide desorbed from the porous structure within 1.5 hours from the start is measured, M2. The amount of carbon dioxide desorbed from the porous structure can be calculated from the results of measuring the difference over time between the carbon dioxide concentration measured by first concentration meter 50 and the carbon dioxide concentration measured by second concentration meter 51. The amount of carbon dioxide desorbed from 1 g of the porous structure in 1.5 hours is calculated based on the amount of substance M2, and the calculated value is specified as the desorption amount b1.

[0143] (Amounts of adsorption and desorption) In the porous structure of this embodiment, the amount of carbon dioxide adsorption a1 when adsorption test A1 is performed is preferably 0.4 mmol / g or more, and may be 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, 2.1 mmol / g or more, 2.2 mmol / g or more, or even 2.3 mmol / g or more. The upper limit of the amount of carbon dioxide adsorption a1 is not particularly limited, and may be, for example, 10 mmol / g.

[0144] In the porous structure of this embodiment, the carbon dioxide desorption amount b1 when desorption test B1 is performed is preferably 0.25 mmol / g or more, and may be 0.3 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, or even 1.8 mmol / g or more. The upper limit of the carbon dioxide desorption amount b1 is not particularly limited, and is, for example, 10 mmol / g.

[0145] The ratio of the desorption amount b1 (mmol / g) to the adsorption amount a1 (mmol / g) (50°C desorption rate) is, for example, 40% or more, and may be 45% or more, 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more. The upper limit of the 50°C desorption rate is not particularly limited and is, for example, 99%.

[0146] <Manufacturing Method> The porous structure according to the second embodiment can be manufactured by, for example, the manufacturing method according to the first embodiment.

[0147] <Use of Porous Structure> The porous structure according to the second embodiment is, for example, an acidic gas adsorbent capable of adsorbing acidic gases. Examples of acidic gases include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SO x ), hydrogen cyanide, nitrogen oxides (NO x ) and the like, and carbon dioxide is preferred.

[0148] The acidic gas adsorbent can be used, for example, by the following method. First, a mixed gas containing an acidic gas is brought into contact with the acidic gas adsorbent. The mixed gas contains, for example, other gases in addition to the acidic gas. Examples of other gases include non-polar gases such as hydrogen and nitrogen, and inert gases such as helium, with nitrogen being preferred. The mixed gas is typically atmospheric air. The mixed gas may also be off-gas from a chemical plant or thermal power plant.

[0149] The temperature of the mixed gas is, for example, room temperature (23°C). The concentration of the acidic gas in the mixed gas is not particularly limited and, under standard conditions (0°C, 101 kPa), is, for example, 0.01 vol% (100 volppm) or more, preferably 0.04 vol% (400 volppm) or more, and may be 1.0 vol% or more. The upper limit of the carbon dioxide concentration in the mixed gas is not particularly limited and, under standard conditions, is, for example, 10 vol%. The pressure of the mixed gas is typically equal to atmospheric pressure in the environment in which the acidic gas adsorbent is used. However, the mixed gas to be contacted with the acidic gas adsorbent may be pressurized.

[0150] The acidic gas adsorbent that has come into contact with the mixed gas adsorbs the acidic gas contained in the mixed gas. The operation of bringing the mixed gas into contact with the acidic gas adsorbent is carried out, for example, until the adsorption of the acidic gas by the acidic gas adsorbent reaches equilibrium.

[0151] Next, the acidic gas adsorbent that has adsorbed the acidic gas is regenerated. The regeneration can be performed, for example, by heating the acidic gas adsorbent. The heating temperature of the acidic gas adsorbent is, for example, 50 to 80°C. The acidic gas adsorbent may be heated under a reduced pressure or vacuum atmosphere. By heating the acidic gas adsorbent, the acidic gas is desorbed from the acidic gas adsorbent. This regenerates the acidic gas adsorbent, allowing it to be reused. The acidic gases, particularly carbon dioxide, desorbed from the acidic gas adsorbent can be used as raw materials for chemical synthesis or as dry ice. The adsorption of acidic gases by the acidic gas adsorbent and the regeneration of the acidic gas adsorbent can be performed using the measuring device 100 (acidic gas adsorption device) described above.

[0152] [Embodiment of Structure Having Porous Structure] Fig. 2A is a perspective view schematically showing an example of a structure having a porous structure. A structure 30A of a third embodiment shown in Fig. 2A includes the porous structure 10 according to the second embodiment and also has ventilation paths 14. The structure 30A is typically a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction.

[0153] The structure 30A includes an adsorbent unit U in which, for example, a corrugated porous structure 10A and a flat porous structure 10B are stacked. In the porous structure 10A, a plurality of peaks 12 and a plurality of valleys 13 are alternately arranged. Air passages 14 are formed between the peaks 12 or valleys 13 of the porous structure 10A and the porous structure 10B. In this embodiment, the direction x is the direction in which the peaks 12 and valleys 13 of the porous structure 10A are alternately arranged (wave direction). The direction y is the stacking direction of the porous structures 10A and 10B in the adsorbent unit U. The direction z is perpendicular to the directions x and y, and is the direction in which the air passages 14 extend.

[0154] The structure 30A includes, for example, a plurality of adsorbent units U. The number of adsorbent units U in the structure 30A is not particularly limited and may be, for example, 2 to 100. In the structure 30A, the plurality of adsorbent units U are stacked in the direction y so that a plurality of porous structures 10A and a plurality of porous structures 10B are arranged alternately. By stacking the plurality of adsorbent units U, the structure 30A has a block shape.

[0155] The ventilation paths 14 are through-holes that penetrate the structure 30A in the direction z. The ventilation paths 14 are surrounded by the porous structures 10A and 10B. In the structure 30A, acidic gases move in the direction z through the ventilation paths 14 and are efficiently adsorbed by the porous structures 10A and 10B.

[0156] In the structure 30A, the smaller the thickness of the porous body S in the porous structures 10A and 10B, the larger the cross-sectional area of ​​the ventilation path 14 can be adjusted. The structure 30A with a large cross-sectional area of ​​the ventilation path 14 is suitable for reducing pressure loss that occurs when the structure 30A comes into contact with acidic gases. The structure 30A with reduced pressure loss can reduce the power of a fan used to move acidic gases, for example. Note that the porous structure 10 tends to have a relatively large amount of amino group substance per unit volume, and therefore tends to be able to sufficiently adsorb acidic gases even when the thickness of the porous body S is small.

[0157] <Modification of structure including porous structure> The shape of structure 30A including porous structure 10 is not limited to that shown in Fig. 2A. Fig. 2B is a perspective view schematically showing a modification of a structure including a porous structure. Structure 30B shown in Fig. 2B has a shape in which one adsorbent unit U is wound around central tube 80. Except for this, the configuration of structure 30B is the same as the configuration of structure 30A.

[0158] The structure 30B has a cylindrical shape. In the structure 30B, the multiple peaks 12 and the multiple valleys 13 of the porous structure 10A are alternately arranged in the circumferential direction of the structure 30B. The ventilation paths 14 formed between the peaks 12 or valleys 13 of the porous structure 10A and the porous structure 10B penetrate the structure 30B in the extension direction of the central tube 80. In the structure 30B, acidic gases move through the ventilation paths 14 in the extension direction of the central tube 80 and are efficiently adsorbed by the porous structures 10A and 10B.

[0159] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0160] Example 1 First, tripropylene glycol-n-butyl ether (manufactured by Dow Chemical, Dowanol) was placed in a container having an inner diameter of 18 mm. TM 0.96 g of ethylene glycol diglycidyl ether (TPnB) and 1.44 g of triethylene glycol butyl methyl ether (Hisorb BTM, manufactured by Toho Chemical Industry Co., Ltd.) were added. 1.10 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) was dissolved in the resulting mixture to prepare a mixture of porogen and epoxy monomer. The boiling point of tripropylene glycol-n-butyl ether is 274°C. The boiling point of triethylene glycol butyl methyl ether is 261°C.

[0161] Next, 1.47 g of polyethyleneimine (SP-012, manufactured by Nippon Shokubai) was added to the container to prepare a mixed solution of porogen, epoxy monomer, and amine monomer.

[0162] The resulting mixture was allowed to stand in a thermostatic chamber at 80° C. for 2 hours to cure, thereby obtaining a block-shaped cured product containing a polymer having an amino group and a porogen.

[0163] The obtained cured body was cut into 2 mm blocks. The cut cured body was left to stand in a thermostatic chamber at 120°C for 1 hour, and then vacuum dried at 80°C for 6 hours to volatilize and remove the porogen. This gave a porous structure of Example 1.

[0164] Example 2 First, 2.66 g of dimethoxytriethylene glycol (manufactured by TCI) was placed in a container having an inner diameter of 18 mm, and 1.04 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) was dissolved therein to prepare a mixed solution of porogen and epoxy monomer. The boiling point of dimethoxytriethylene glycol is 216°C.

[0165] Next, 1.39 g of polyethyleneimine (SP-012, manufactured by Nippon Shokubai) was added to the container to prepare a mixed solution of porogen, epoxy monomer, and amine monomer.

[0166] A porous structure of Example 2 was obtained in the same manner as in Example 1, except that the above mixed solution was used.

[0167] Example 3 First, tripropylene glycol-n-butyl ether (manufactured by Dow Chemical, Dowanol) was placed in a container having an inner diameter of 18 mm. TM 0.98 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) was dissolved in the mixture to prepare a mixed solution of porogen and epoxy monomer. The boiling point of dimethoxytetraethylene glycol is 275°C.

[0168] Next, 0.89 g of polyethyleneimine (SP-003, manufactured by Nippon Shokubai) was added to the container to prepare a mixed solution of porogen, epoxy monomer, and amine monomer.

[0169] A porous structure of Example 3 was obtained in the same manner as in Example 1, except that the above mixed solution was used.

[0170] Comparative Example 1 First, 2.40 g of ethyl acetate was placed in a container having an inner diameter of 18 mm, and 1.10 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) was dissolved therein to prepare a mixed solution of porogen and epoxy monomer. The boiling point of ethyl acetate is 77.4°C.

[0171] Next, 1.47 g of polyethyleneimine (SP-012, manufactured by Nippon Shokubai) was added to the container to prepare a mixed solution of porogen, epoxy monomer, and amine monomer.

[0172] Except for using the above mixed solution, the same operation as in Example 1 was carried out. In Comparative Example 1, a porous structure could not be obtained.

[0173] <Porogen Content> The porogen content of the porous structures of Examples 1 to 3 was measured as follows. The measurement results are shown in Table 1.

[0174] Approximately 0.05 g of the porous structure was collected, 5 mL of methanol was added, and the mixture was shaken overnight. This solution was filtered through a membrane filter (pore size 0.45 μm). The obtained filtrate was subjected to LC / MS analysis to measure the porogen content. The LC / MS device and column used are as follows: Device: Acquity UPLC / Xevo G2-XS QTOF manufactured by Waters Column: Acquity UPLC BEH C18 (2.1 mmφ×100 mm, 1.7 μm) manufactured by Waters

[0175] <BET Specific Surface Area> The BET specific surface area of ​​the porous structures of Examples 1 to 3 was measured by a method conforming to the provisions of JIS Z8830:2013. For the measurement, a specific surface area measuring device (manufactured by Microtrac-Bell, product name "BERSORP-mini") was used. The results are shown in Table 1.

[0176] <Carbon dioxide adsorption test> The adsorption test A1 was carried out by the above-mentioned method to measure the adsorption amount a1 for the porous structures of Examples 1 to 3. The test results are shown in Table 1.

[0177] The abbreviations in Table 1 are as follows: PEI: polyethyleneimine (Epomin SP-012, weight average molecular weight approximately 1200, manufactured by Nippon Shokubai) EDE: ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX) TPnB: tripropylene glycol-n-butyl ether (DOWANOL, manufactured by Dow Chemical) TM TPnB) Triglyme: dimethoxytriethylene glycol (manufactured by TCI) Tetraglyme: dimethoxytetraethylene glycol (manufactured by TCI) BTM: triethylene glycol butyl methyl ether (manufactured by Toho Chemical Industry, Hisorb BTM) EtAc: ethyl acetate

[0178]

[0179] By heating a resin structure containing a polymer and a porogen having a boiling point of 200° C. or higher, the porous structures of Examples 1 to 3, which are acidic gas adsorbents, could be obtained. In Comparative Example 1, the boiling point of the porogen was lower than 200° C., so the porogen was volatilized by heating when obtaining the resin structure as a cured body, and a porous structure could not be formed.

[0180] According to the manufacturing method of the present invention, the burden on the environment during the production of a porous structure can be reduced.

Claims

1. A method for producing a porous structure, comprising a step of removing the porogen from a resin structure containing a polymer and a porogen by heating the resin structure, wherein the boiling point of the porogen is 200°C or higher.

2. The method for producing a porous structure according to claim 1, wherein the boiling point of the porogen is 350° C. or lower.

3. The method for producing a porous structure according to claim 1, wherein the porogen comprises at least one selected from the group consisting of (poly)alkyleneoxy monoalkyl ethers and (poly)alkyleneoxy dialkyl ethers.

4. The method for producing a porous structure according to claim 1, wherein the porogen comprises at least one selected from the group consisting of dimethoxytriethylene glycol, triethylene glycol butyl methyl ether, dimethoxytetraethylene glycol, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, and tripropylene glycol dimethyl ether.

5. The method for producing a porous structure according to claim 1, wherein the heating is carried out at 140°C or less.

6. The method for producing a porous structure according to claim 1, wherein the polymer has an amino group.

7. The method for producing a porous structure according to claim 6, wherein the polymer is an amine polymer containing constitutional units derived from an epoxy monomer.

8. A method for producing a porous structure according to claim 6, further comprising a step of reacting a group of compounds, including a compound C1 having an amino group and a compound C2 having an epoxy group, with the porogen in a mixed liquid to obtain the resin structure.

9. The method for producing a porous structure according to claim 1, wherein the porous structure is an acid gas adsorbent.

10. A porous structure comprising a porogen having a boiling point of 200° C. or higher.

11. The porous structure of claim 10, wherein the boiling point of the porogen is 350° C. or less.

12. Specific surface area is 1.0 m 2 The porous structure according to claim 10, wherein the molecular weight is 1 / g or more.

13. The porous structure according to claim 10, wherein the porogen content is 50 μg / g or more and 30,000 μg / g or less.

14. The porous structure according to claim 10, comprising a polymer having an amino group as a main component.

15. The porous structure according to claim 10, wherein the porous structure is an acid gas adsorbent.

16. The porous structure according to claim 15, in which, when adsorption test A1 is performed, the amount a1 of adsorbed carbon dioxide is 0.35 mmol / g or more. Adsorption test A1: A mixed gas composed of carbon dioxide, nitrogen and water vapor is continuously fed into the container containing the porous structure for 15 hours, where the concentration of carbon dioxide in the mixed gas is 400 vol ppm, the temperature of the mixed gas is 23° C., and the humidity of the mixed gas is 50% RH.

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