N-oxy radical group-containing polymer, resin composition, and acid gas separation device

Abstract

Provided are an N-oxy radical group-containing polymer, a resin composition, and an acid gas separation device that, when used in electrochemical acid gas separation applications, have excellent durability in repeated acid gas separation and excellent radical stability in high-temperature environments. The N-oxy radical group-containing polymer according to the present disclosure, in a solution state at a concentration of 0.02 mass% with toulene as a solvent, has a line width (ΔH) of 0.8-3.0 mT for a resonance peak derived from an organic radical appearing at a magnetic field strength of 339-345 mT, as measured using an electron spin resonance measurement device.

Description

N-oxy radical group-containing polymer, resin composition, and acid gas separation device

[0001] This disclosure relates to an N-oxy radical group-containing polymer, a resin composition containing the N-oxy radical group-containing polymer, and an acid gas separation device.

[0002] Carbon dioxide is widely used industrially as a foaming gas, dry ice for cooling, an extraction solvent (supercritical state) for extracting caffeine and other substances, carbon dioxide lasers, a refrigerant for compressors, and an atmospheric gas for controlled atmosphere (CA) storage of fresh agricultural products. Therefore, there is a need for technologies to separate carbon dioxide from gases such as air that contain it. The importance of carbon dioxide separation technology is also increasing from the perspective of preventing global warming.

[0003] Various methods have been proposed for separating carbon dioxide from mixed gases such as air. For example, one method involves using an adsorbent to adsorb carbon dioxide from the air, and then desorbing the carbon dioxide from the adsorbent. Another method is pressure-swing adsorption (PSA), in which carbon dioxide is adsorbed onto an adsorbent under high pressure, and then desorbed by reducing the pressure. Examples of such adsorbents include activated carbon, amine-based solvents, and aqueous potassium carbonate solutions. However, carbon dioxide separation methods using adsorbents, such as the PSA method mentioned above, require pressurization, depressurization, and heat treatment during the adsorption and desorption of carbon dioxide. Therefore, these methods have the drawback of requiring a relatively large amount of energy and large-scale equipment.

[0004] To overcome these drawbacks, methods have been proposed that utilize chemical species that adsorb and desorb carbon dioxide using electrochemical redox reactions. Compounds containing an N-oxy radical group are attracting attention as redox species that electrochemically adsorb and desorb carbon dioxide.

[0005] Patent Document 1 discloses a carbon dioxide separation device having a pair of electrodes permeable to gas, an electrolyte membrane sandwiched between these electrodes, and a voltage application unit for applying a voltage between the pair of electrodes. The electrolyte membrane contains a non-volatile electrolyte and a non-volatile redox compound. This redox compound has the property of adsorbing carbon dioxide by electrolytic reduction and desorbing the adsorbed carbon dioxide by electrolytic oxidation. The example describes an electrolyte membrane containing a redox compound having an N-oxy radical group in its molecule.

[0006] Patent Document 2 discloses an acidic gas separation device having the same electrode and other components as Patent Document 1. The electrolyte membrane in this document comprises at least one selected from the group consisting of a high molecular weight redox compound with a radicalization rate of 90% or more, a high molecular weight redox compound having a quinone group in its molecule, and a high molecular weight redox compound having an imino group in its molecule, and a non-volatile electrolyte. In the examples, an electrolyte membrane containing a polymer having an N-oxy radical group in its molecule is described and shown to have the ability to separate carbon dioxide.

[0007] Japanese Patent Publication No. 2021-102198, International Publication No. 2022 / 019065

[0008] When electrochemically separating carbon dioxide using compounds containing N-oxy radical groups, it is required that carbon dioxide can be repeatedly separated from a gas containing carbon dioxide over a long period of time, while maintaining performance even under harsh operating environments such as high temperatures. While the above describes the challenges in carbon dioxide separation, similar challenges can arise in the separation of acidic gases. Furthermore, similar challenges can arise in components utilizing oxidation-reduction reactions and devices using them.

[0009] This disclosure has been made in view of the above-mentioned problems, and its purpose is to provide an N-oxy radical group-containing polymer, resin composition, and acid gas separation device that exhibit excellent repeated durability in acid gas separation and excellent radical stability in high-temperature environments when used in electrochemical acid gas separation applications.

[0010] The present inventors have conducted diligent studies to achieve the above objectives and have completed the present disclosure, which includes the following embodiments: [1] An N-oxy radical group-containing polymer having an N-oxy radical group in its molecule, measured in an electron spin resonance spectrometer at a concentration of 0.02% by mass in a solution with toluene as the solvent, with a linewidth (ΔH) of the resonance peak originating from an organic radical appearing at a magnetic field strength of 339-345 mT being 0.8-3.0 mT. [2] An N-oxy radical group-containing polymer having an N-oxy radical group in its molecule, measured in a quartz glass cell with an optical path length of 1 cm at a concentration of 10% by mass in a solution with toluene as the solvent, with an absorbance of 2.00-4.20 at a wavelength of 470 nm. [3]: A resin composition comprising a polymer (A) having an N-oxy radical group in its molecule and a redox compound (B) having a molecular weight of less than 1000, wherein the weight-average molecular weight of polymer (A), determined on a standard polystyrene basis by gel permeation chromatography, is 10,000 to 500,000, and the content of redox compound (B) is 0.1 to 30% by mass. [4]: ​​The resin composition according to [3], wherein polymer (A) is the N-oxy radical group-containing polymer according to [1]. [5]: The resin composition according to [3], wherein polymer (A) is the N-oxy radical group-containing polymer according to [2]. [6]: The resin composition according to any one of [3] to [5], wherein polymer (A) contains N-oxy radical group-containing monomer units, and the content of the N-oxy radical group-containing monomer units relative to the total mass of all structural units constituting polymer (A) is 50 to 100% by mass. [7]: The resin composition according to any one of [3] to [6], wherein the redox compound (B) is a redox compound having an N-oxy radical group in its molecule. [8]: The resin composition according to any one of [3] to [7], wherein the redox compound (B) is a compound represented by the following formula (4). (In formula (4), R ５ , R ６ , R ７ and R ８ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ５ and R ６ At least one of them is an alkyl group having 1 to 6 carbon atoms, R７ and R ８ At least one of them represents an alkyl group having 1 to 6 carbon atoms. R ５ and R ６ may be bonded to each other to form a cyclic structure, and R ７ and R ８ may be bonded to each other to form a cyclic structure. R １２ represents a hydrogen atom or a substituent, and n represents 0 or 1. ) [9]: A resin composition containing the N-oxy radical group-containing polymer described in [1].

[10] : A resin composition containing the N-oxy radical group-containing polymer described in [2].

[11] : A pair of electrodes at least one of which is gas-permeable, an electrolyte membrane provided between the pair of electrodes, and a voltage application unit that applies a voltage between the pair of electrodes, wherein the electrolyte membrane contains the N-oxy radical group-containing polymer described in any one of [1] or [2], or the resin composition described in any one of [3] to

[10] , and the N-oxy radical group-containing polymer or the resin composition is electrochemically reduced to adsorb an acidic gas and electrochemically oxidized to desorb the adsorbed acidic gas, an acidic gas separation device.

[12] : An air purifier provided with the acidic gas separation device described in

[11] .

[13] : An air conditioner provided with the acidic gas separation device described in

[11] .

[14] : A carbon dioxide concentrator provided with the acidic gas separation device described in

[11] .

[0011] According to the present disclosure, when used in the electrochemical separation of acidic gases, an N-oxy radical group-containing polymer, a resin composition, and an acidic gas separation device having excellent repeated durability of acidic gas separation and excellent radical stability in a high-temperature environment can be provided, which has an excellent effect.

[0012] A schematic cross-sectional view showing the configuration of an acidic gas separation device according to one embodiment of the present implementation. A schematic cross-sectional view showing the configuration of the acidic gas separation device during charging according to another embodiment of the present implementation. N-oxy radical electron spin resonance spectra of Examples and Comparative Examples. Absorption spectra of polymers (A) etc. used in Examples and Comparative Examples.

[0013] The following describes an example of an embodiment to which this disclosure applies. This disclosure is not limited to this embodiment, and other embodiments may also fall within the scope of this disclosure as long as they are consistent with the spirit of this disclosure. Furthermore, polymer (A) may satisfy any one of the first to third embodiments or two or more embodiments. Furthermore, the resin composition of this disclosure may satisfy any one of the third to fifth embodiments or two or more embodiments. Furthermore, the numerical values ​​"A to B" specified herein include numerical values ​​A and B. The numerical values ​​specified herein are values ​​obtained by the methods disclosed in the embodiments or examples. Unless otherwise noted, the various components appearing herein may be used independently, individually, or in combination of two or more. (Meth)acrylic is a general term for acrylic and methacrylic. Unless otherwise specified herein, "units" contained in polymers are repeating units contained in polymers, which are monomer units derived from raw material monomers or derived units derived from one or more monomer units.

[0014] 1. N-oxyradical group-containing polymer [First embodiment] The N-oxyradical group-containing polymer (A) according to the first embodiment (hereinafter also referred to as polymer (A)) is a compound produced by the polymerization of a plurality of monomers, and is a polymer having an N-oxyradical group in its molecule. Polymer (A) is characterized in that, in a solution state with a concentration of 0.02% by mass using toluene as a solvent, the linewidth (ΔH) of the resonance peak originating from an organic radical that appears at a magnetic field strength of 339 to 345 mT (millitesla), as measured by an electron spin resonance (ESR) measuring device, is 0.8 to 3.0 mT.

[0015] (ESR) Electron spin resonance (ESR) measurement is a spectroscopic analysis that observes the transitions between energy levels that occur when unpaired electrons are placed in a magnetic field. The measurement is performed by sweeping the magnetic field under microwave irradiation. As the applied magnetic field increases, the energy gap ΔE, which is divided by the Zeeman effect, increases, and a resonance peak is observed when ΔE becomes equal to the microwave energy. The specific method for measuring ESR is as shown in the Examples section below.

[0016] The observation of resonance peaks originating from organic radicals at magnetic field strengths of 339–345 mT indicates that polymer (A) has unpaired electrons.

[0017] (Linewidth of resonance peak (ΔH)) In ESR measurements of polymer (A), when measured in a solution state with toluene as the solvent and a concentration of 0.02 mass%, the linewidth (ΔH) of the resonance peak originating from organic radicals that appears at a magnetic field strength of 339 to 345 mT is 0.8 to 3.0 mT. The lower limit of ΔH is preferably 0.85 mT, more preferably 0.9 mT, even more preferably 0.95 mT, and particularly preferably 1.0 mT. The upper limit of ΔH is preferably 2.9 mT, more preferably 2.8 mT, even more preferably 2.7 mT, and particularly preferably 2.5 mT. When the ΔH of polymer (A) is 0.8 to 3.0 mT, it exhibits excellent repeated durability in the separation of acidic gases.

[0018] The reason for this is thought to be as follows: The ESR spectrum originating from the unpaired electrons of the N-oxy radical is related to the electron spin of the unpaired electrons on oxygen, and the adjacent electrons. １４The splitting of resonance peaks occurs due to hyperfine interactions with the nuclear spin of the N nucleus. However, in ESR measurements, if magnetic dipole interactions or exchange interactions between unpaired electrons cannot be ignored, for example, if the sample solution is highly concentrated and the distance between radical molecules is small, the magnetic interactions are averaged out, and the resonance peaks on the ESR spectrum are coupled and broadened. In this disclosure, the concentration of the sample solution used for the ESR measurement was 0.02 mass%, and under these dilute conditions, the aforementioned averaging of magnetic interactions does not occur. Therefore, in the case of a compound having one unpaired electron per molecule, the distance between radical molecules is sufficiently large, and the linewidth ΔH of the resonance peak is less than 0.8 mT. On the other hand, if the ΔH of polymer (A) is 0.8 mT to 3.0 mT despite the dilute sample solution, this indicates that averaging of magnetic interactions is occurring due to magnetic dipole interactions or exchange interactions between unpaired electrons, and it is presumed that the local concentration of unpaired electrons in the sample solution is high. This indicates that polymer (A) is a polymer in which multiple unpaired electrons are located in close proximity within a single molecular chain. It is believed that using such a polymer will result in superior repeated durability and separation speed in the separation of acidic gases.

[0019] The weight-average molecular weight (Mw) of polymer (A), determined by gel permeation chromatography (GPC) on a standard polystyrene basis, is preferably 10,000 to 500,000. The lower limit of Mw for polymer (A) may be 11,000, 12,000, 13,000, 14,000, or 15,000. The upper limit of Mw for polymer (A) may be 400,000, 300,000, 200,000, 100,000, or 50,000. When Mw is 10,000 or higher, the durability of the component using the resin composition when acidic gas separation is repeated is improved. When Mw is 500,000 or lower, the acidic gas separation rate of the component using the resin composition is improved. From the viewpoint of film-forming properties, the upper limit of Mw is more preferably 50,000.

[0020] Polymer (A) may be a polymer containing an N-oxy radical group-containing monomer unit represented by the following formula (1), and optionally one or more other monomer units. In formula (1), R １ , R ２ , R ３ and R ４ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. １ and R ２ At least one of them is an alkyl group having 1 to 6 carbon atoms, R ３ and R ４ At least one of them represents an alkyl group having 1 to 6 carbon atoms. １ and R ２ They may bond with each other to form a ring structure, R ３ and R ４ These may combine with each other to form a ring structure. １１ represents a hydrogen atom or a methyl group, X represents a single bond or a divalent linking group, and n represents 0 or 1.

[0021] The aforementioned R １ ~R ４ It is more preferable that three or more of the atoms are alkyl groups having 1 to 6 carbon atoms, and even more preferable that all four atoms are alkyl groups having 1 to 6 carbon atoms. That is, the compound represented by formula (1) is preferably a compound in which two quaternary carbon atoms are bonded to an N-oxy radical group. Furthermore, it is preferable that the compound is a compound in which two quaternary carbon atoms are bonded to an N-oxy radical group, or a compound having a group from which one hydrogen atom has been removed. It is thought that the compound in which two quaternary carbon atoms are bonded to an N-oxy radical group can suppress the decomposition of the N-oxy radical group by abstracting a hydrogen radical from a carbon adjacent to the N-oxy radical group. Therefore, it is thought that the compound can more effectively adsorb and release acidic gases. For this reason, by including such a compound in the resin composition, the acidic gas absorption rate of the resin composition becomes good.

[0022] The content of N-oxy radical group-containing monomer units in polymer (A) is not particularly limited, but from the viewpoint of achieving excellent repeated durability and separation speed, it is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass, relative to the total structural units. The content of other monomer units in polymer (A) (total amount if there are multiple types) is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 10% by mass or less, relative to the total structural units.

[0023] The N-oxy radical group-containing monomer unit of this disclosure is preferably an N-oxy radical group-containing (meth)acrylic acid ester monomer unit represented by the following formula (2).

[0024] R in equation (2) １ , R ２ , R ３ and R ４ R in equation (1) １ , R ２ , R ３ and R ４ The following description is used as reference. R in equation (2) １１ and n are R in equation (1) １１ The description of and n is used as reference. Y represents a single bond or a divalent linking group.

[0025] The method for introducing N-oxy radical group-containing monomer units into polymer (A) is not particularly limited, but for example, one method involves oxidizing the secondary amino group of a polymer containing a secondary amino group-containing monomer unit represented by formula (3) to nitroxide it.

[0026] R in equation (3) １ , R ２ , R ３ and R ４ R in equation (1) １ , R ２ , R ３ and R ４ The following description is used as reference. X, R in equation (3) １１ and n are X, R in equation (1). １１ And refer to the description of n.

[0027] The method for producing a polymer containing a secondary amino group-containing monomer unit represented by formula (3) above is not limited, but for example, it can be produced by the following method. First, a reaction mixture is prepared (step a) containing a monomer (hereinafter referred to as monomer (M)) used for polymerization of polymer (A), which contains a monomer corresponding to the secondary amino group-containing monomer unit represented by formula (3) above (hereinafter referred to as monomer (m1)) and may also contain a monomer copolymerizable with monomer (hereinafter referred to as monomer (m2)), and a radical polymerization initiator. A preferred example of monomer (m1) is a secondary amino group-containing (meth)acrylic acid ester monomer.

[0028] Preferred examples of secondary amino group-containing monomers (monomer (m1)) include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, and 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine. Examples include tramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine.

[0029] Other monomers (m2) used as raw materials for polymer (A) are not particularly limited, but preferred examples include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and norborneyl (meth)acrylate; aromatic vinyl monomers such as styrene and α-methylstyrene; (meth)acrylamide; and vinyl cyanide monomers such as (meth)acrylonitrile. The method for introducing the other monomers into polymer (A) is not particularly limited, but for example, a method of copolymerizing the corresponding monomer (m2) during the polymerization of the secondary amino group-containing monomer can be used. Among these monomers (m2), alkyl (meth)acrylates, aromatic vinyl monomers, and vinyl cyanide monomers are preferred from the viewpoint of heat decomposition resistance, and methyl (meth)acrylate and styrene are more preferred.

[0030] Here, monomer (M) is a general term for all monomers used in the polymerization system, and in the case of homopolymerization, it is one type of monomer (m1), and in the case of copolymerization, it is a mixture of monomers. Copolymers include polymers containing two or more types of monomer (m1). In addition to the embodiments described above, copolymers include polymers obtained by using one or more types of monomer (m1) and one or more types of monomer (m2) as a monomer mixture. The reaction mixture refers to all compounds charged into a tank reactor, and includes the monomer mixture and a radical polymerization initiator, and may also include optional components. Optional components include, for example, chain transfer agents, solvents, and additives that do not depart from the spirit of this disclosure.

[0031] Next, polymerization is carried out by a batch reaction in a tank reactor at 60 to 120°C (step b). In step b, a radical polymerization initiator may be further added. The amount of radical polymerization initiator per 100 parts by mass of monomer (M) is, for example, 0.01 to 1 part by mass in total. It may be a homopolymer or a copolymer. In the case of a copolymer, its form is not limited. For example, block copolymers and random copolymers can be mentioned. Polymer (A) is obtained by oxidizing the secondary amino groups of a polymer containing secondary amino group monomer units to nitroxide them, as described above.

[0032] The polymer (A) after the nitroxide reaction may contain unreacted secondary amino group-containing monomer units. The content of secondary amino group-containing monomer units in polymer (A) is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0033] [Second Embodiment] The N-oxy radical group-containing polymer (A) according to the second embodiment (hereinafter also referred to as polymer (A)) is a compound produced by the polymerization of a plurality of monomers, and is a polymer having an N-oxy radical group in its molecule. Polymer (A) is characterized in that, in a solution state of 10% by mass with toluene as the solvent, the absorbance at a wavelength of 470 nm measured in a quartz glass cell with an optical path length of 1 cm is 2.00 to 4.20.

[0034] Polymer (A) may be a polymer containing an N-oxy radical group-containing monomer unit represented by formula (1) as described in the first embodiment, and optionally one or more other monomer units. The description of polymer (A) represented by formula (1) is the same as that described in the first embodiment and applies to the second embodiment as well.

[0035] As described above, the polymer (A) according to the second embodiment has an absorbance of 2.00 to 4.20 at a wavelength of 470 nm, measured in a 10% by mass solution with toluene as the solvent in a quartz glass cell with a path length of 1 cm. The lower limit of the absorbance is preferably 2.50, more preferably 3.00, and even more preferably 3.50. When the absorbance is between 2.00 and 4.20, the amount of N-oxy radical groups in the polymer chain increases, and the number of reaction sites with carbon dioxide increases, thereby improving the carbon dioxide separation rate of the component using polymer (A). As shown in Figure 4, which will be described later, polymer (A) having N-oxy radical groups has a maximum absorption wavelength of 470 nm. In addition, since N-oxy radical groups absorb colors in the 400 to 600 nm range, the solution is red due to the complementary color.

[0036] 2. Resin Composition [Third Embodiment] The resin composition of the third embodiment comprises one or more polymers (A) having an N-oxy radical group in the molecule, and one or more redox compounds (B) excluding polymer (A) with a molecular weight of less than 1000. Here, "excluding polymer (A)" means that dimers, trimers, etc. of monomers constituting polymer (A) that have an N-oxy radical group in the molecule are classified as polymer (A) and not redox compounds (B), even if their molecular weight is less than 1000. Polymer (A) is a compound produced by the polymerization of multiple monomers, and its weight-average molecular weight (Mw) determined by gel permeation chromatography (GPC) on a standard polystyrene (PS) basis is 10,000 to 500,000. The content of redox compounds (B) is 0.1 to 30% by mass in 100% by mass of the resin composition.

[0037] According to the resin composition of the third embodiment, by combining a polymer (A) having an Mw of 10,000 to 500,000 with a specific amount of a low molecular weight component redox compound (B), when applied as a redox material for the electrolyte membrane of an acidic gas separation device, it exhibits excellent acidic gas separation speed and excellent durability for repeated acidic gas separation.

[0038] The polymer (A) according to the third embodiment is a compound produced by the polymerization of multiple monomers, and as described above, is a polymer having an N-oxy radical group in its molecule. A polymer (A) obtained by polymerizing monomers having an N-oxy radical group in its molecule is classified as polymer (A) even if its molecular weight is less than 1000. The Mw of polymer (A), calculated in terms of standard PS by GPC, is between 10,000 and 500,000.

[0039] In the resin composition of the third embodiment, the content of polymer (A) is preferably 70 to 99.9% by mass. The lower limit of the polymer (A) content is more preferably 75% by mass, even more preferably 80% by mass, and even more preferably 85% by mass. The upper limit of the polymer (A) content is more preferably 99.8% by mass, even more preferably 99.7% by mass, and even more preferably 99.5% by mass.

[0040] Polymer (A) may be a polymer containing an N-oxy radical group-containing monomer unit represented by the following formula (1), and optionally one or more other monomer units. In formula (1), R １ , R ２ , R ３ and R ４ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. １ and R ２ At least one of them is an alkyl group having 1 to 6 carbon atoms, R ３ and R ４ At least one of them represents an alkyl group having 1 to 6 carbon atoms. １ and R ２ They may bond with each other to form a ring structure, R ３ and R ４ These may combine with each other to form a ring structure. １１ represents a hydrogen atom or a methyl group, X represents a single bond or a divalent linking group, and n represents 0 or 1.

[0041] The aforementioned R １ ~R ４It is more preferable that three or more of the atoms are alkyl groups having 1 to 6 carbon atoms, and even more preferable that all four atoms are alkyl groups having 1 to 6 carbon atoms. That is, the compound represented by formula (1) is preferably a compound in which two quaternary carbon atoms are bonded to an N-oxy radical group. Furthermore, it is preferable that the compound is a compound in which two quaternary carbon atoms are bonded to an N-oxy radical group, or a compound having a group from which one hydrogen atom has been removed. It is thought that the compound in which two quaternary carbon atoms are bonded to an N-oxy radical group can suppress the decomposition of the N-oxy radical group by abstracting a hydrogen radical from a carbon adjacent to the N-oxy radical group. Therefore, it is thought that the compound can more effectively adsorb and release acidic gases. For this reason, by including such a compound in the resin composition, the acidic gas absorption rate of the resin composition becomes good.

[0042] The content of N-oxy radical group-containing monomer units in polymer (A) is not particularly limited, but from the viewpoint of achieving excellent repeated durability and separation speed, it is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass, relative to the total structural units. The content of other monomer units in polymer (A) (total amount if there are multiple types) is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 10% by mass or less, relative to the total structural units.

[0043] The N-oxy radical group-containing monomer unit of the third embodiment is preferably an N-oxy radical group-containing (meth)acrylic acid ester monomer unit represented by the following formula (2).

[0044] R in equation (2) １ , R ２ , R ３ and R ４ R in equation (1) １ , R ２ , R ３ and R ４ The following description is used as reference. R in equation (2) １１ and n are R in equation (1) １１The description of and n is used as reference. Y represents a single bond or a divalent linking group.

[0045] The weight-average molecular weight (Mw) of polymer (A) is 10,000 to 500,000, as described above. The lower limit of Mw for polymer (A) may be 11,000, 12,000, 13,000, 14,000, or 15,000. The upper limit of Mw for polymer (A) is preferably 400,000, more preferably 300,000, even more preferably 250,000, even more preferably 200,000, and particularly preferably 180,000. When Mw is 10,000 or more, the durability of the component using the resin composition when acidic gas separation is repeated is improved. When Mw is 500,000 or less, the rate of acidic gas separation of the component using the resin composition is improved.

[0046] The method for introducing N-oxy radical group-containing monomer units into polymer (A) is not particularly limited, but for example, one method involves oxidizing the secondary amino group of a polymer containing a secondary amino group-containing monomer unit represented by formula (3) to nitroxide it.

[0047] R in equation (3) １ , R ２ , R ３ and R ４ R in equation (1) １ , R ２ , R ３ and R ４ The following description is used as reference. X, R in equation (3) １１ and n are X, R in equation (1). １１ The description of n is incorporated below. The method for producing a polymer containing a secondary amino group-containing monomer unit represented by formula (3) above is not limited, but for example, it can be produced by the following method.

[0048] First, a reaction mixture is prepared (step a) containing a monomer (hereinafter referred to as monomer (M)) used for polymerization of polymer (A), which includes a monomer corresponding to a secondary amino group-containing monomer unit represented by the above formula (3) (hereinafter referred to as monomer (m1)), and which may also include a monomer copolymerizable with monomer (m1) (hereinafter referred to as monomer (m2)), and a radical polymerization initiator. A preferred example of monomer (m1) is a secondary amino group-containing (meth)acrylic acid ester monomer.

[0049] Preferred examples of the secondary amino group-containing monomer (monomer (m1)) and other monomers (m2) are the same as those described in the first embodiment.

[0050] Monomer (M), as described in the first embodiment, is a general term for all monomers used in the polymerization system, and in the case of homopolymerization, it is one type of monomer (m1), and in the case of copolymerization, it is a mixture of monomers. Copolymers include polymers containing two or more types of monomer (m1). In addition to the embodiments described above, copolymers include polymers obtained by using one or more types of monomer (m1) and one or more types of monomer (m2) as a monomer mixture. The reaction mixture refers to all compounds charged into the tank reactor, and includes the monomer mixture and a radical polymerization initiator, and may also include optional components. Optional components include, for example, chain transfer agents, solvents, and additives that do not depart from the spirit of this disclosure.

[0051] Next, polymerization is carried out by a batch reaction in a tank reactor at 60 to 120°C (step b). In step b, a radical polymerization initiator may be further added. The amount of radical polymerization initiator per 100 parts by mass of monomer (M) is, for example, 0.01 to 1 part by mass in total. It may be a homopolymer or a copolymer. In the case of a copolymer, its form is not limited. For example, block copolymers and random copolymers can be mentioned. Polymer (A) is obtained by oxidizing the secondary amino groups of a polymer containing secondary amino group monomer units to nitroxide them, as described above.

[0052] The polymer (A) after the nitroxide reaction may contain unreacted secondary amino group-containing monomer units. The content of secondary amino group-containing monomer units in polymer (A) is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0053] 1-2. Redox Compound (B) Redox compound (B) is a compound that can undergo repeated reduction and oxidation reactions, and is a compound with a molecular weight of less than 1000, excluding polymer (A). The reduction reaction may be an electrochemical reaction with an electrode (electrolytic reduction). The oxidation reaction may be an electrochemical reaction with an electrode (electrolytic oxidation) (the same applies in subsequent embodiments).

[0054] The content of redox compound (B) is 0.1 to 30% by mass relative to 100% by mass of the resin composition of the third embodiment. The lower limit of the content of redox compound (B) is preferably 0.2% by mass, more preferably 0.3% by mass, and even more preferably 0.5% by mass. The upper limit of the content of redox compound (B) is preferably 25% by mass, more preferably 20% by mass, and even more preferably 15% by mass. When the content of redox compound (B) in the resin composition of the third embodiment is 0.1% by mass or more, the separation rate of acidic gases in the component using the resin composition of the third embodiment is good, and when it is 30% by mass or less, the durability when the separation of acidic gases in the component using the resin composition of the third embodiment is repeated is good.

[0055] The molecular weight of redox compound (B) is less than 1000, preferably 900 or less, more preferably 800 or less, even more preferably 700 or less, and even more preferably 600 or less. When the molecular weight of redox compound (B) is less than 1000, the carbon dioxide separation rate of the component using the resin composition is improved. The molecular weight of redox compound (B) is a value measured by mass spectrometry (MS). For ionization of the sample in mass spectrometry, known methods such as electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) can be applied.

[0056] The structure of redox compound (B) is not particularly limited. Examples of redox compound (B) include compounds having at least one of a quinone group and an N-oxy radical group in their molecule. Specifically, examples include compounds having a quinone group in their molecule, compounds having an N-oxy radical group in their molecule, and compounds having both a quinone group and an N-oxy radical group in their molecule. Examples of compounds having a quinone group in their molecule include benzoquinone, naphthoquinone, and anthraquinone.

[0057] Redox compound (B) is preferably a redox compound having an N-oxy radical group in its molecule. The fact that redox compound (B) is a compound having an N-oxy radical group in its molecule improves the repeated durability of carbon dioxide absorption of the component containing the resin composition. Examples of redox compounds having an N-oxy radical group in their molecule include 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidine-4-yloxy)xylene, 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl, N,N-di-tert-butylnitroxide radical, N,N-diphenylnitroxide radical, N,N-dinaphthylnitroxide radical, N,N-di-2-methylphenylnitroxide radical, N,N-di-3- Methylphenylnitroxide radical, N,N-di-4-methylphenylnitroxide radical, N,N-di-2-ethylphenylnitroxide radical, N,N-di-2-propylphenylnitroxide radical, N,N-di-2-butylphenylnitroxide radical, N,N-di-2-pentylphenylnitroxide radical, N,N-di-2-hexylphenylnitroxide radical, N,N-di-2-isopropylphenylnitroxide radical, N,N-di-2-iso Butylphenyl nitroxide radical, N,N-di-2-sec-butylphenyl nitroxide radical, N,N-di-2-tert-butylphenyl nitroxide radical, N,N-di-4-tert-butylphenyl nitroxide radical, N,N-di-(3,5-di-tert-butyl)phenyl nitroxide radical, N,N-di-4-pyridyl nitroxide radical, N,N-di-4-pyridazyl nitroxide radical, poly(ethylene glycol)-bis-2,2,6 ,6-tetramethylpiperidinyl oxyradical, N-phenyl-N-oxy-tert-butylamine, N-naphthyl-N-oxy-tert-butylamine, N-tert-butyl-N-oxy-2-quinoline, 2,2,6,6-tetramethylpiperidinyl oxyradical (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyl oxyradical, 4-amino-2,2,6,6-tetramethylpiperidinyl oxyradical, 4-carboxy-2,2,6,6 - tetramethylpiperidinyl oxyl radical, 4 - methoxy - 2,2,6,6 - tetramethylpiperidinyl oxyl radical, 4 - oxo - 2,2,6,6 - tetramethylpiperidinyl oxyl radical, 4 - acetamido - 2,2,6,6 - tetramethylpiperidinyl oxyl radical, 4 - octyloxy - 2,2,6,6 - tetramethylpiperidinyl oxyl radical, 2,2,5,5 - tetramethylpyrrolidine - oxyl radical, 3 - carbamoyl - 2,2,5,5 - tetramethylpyrrolidine - oxyl radical, 3 - carboxy - 2,2,5,5 - tetramethylpyrrolidine - oxyl radical, 2,2,6,6 - tetramethylmorpholine - N - oxyl radical and 2,2,6,6 - tetramethylmorpholinepiperazine - N - oxyl radical, γ - dimethyl - butyrolactam - N - oxide, ε - dimethyl - valerolactam - N - oxide, 3,4 - dihydroquinolin - 2 - one - N - oxide, 3, · 3 - dimethylisoquinolin - 1 - one - N - oxide, 3,3 - dimethyl - 1H - indole - 2(3H) - one - N - oxide, 3,3 - dimethyl - isoindoline - 1 - one - N - oxide and N - t - butylbenzoic acid - N - oxide, 1α,2α - cyclohexanedicarboximide - N - oxyl, phthalimide - N - oxyl, 3 - methyl - phthalimide - N - oxyl, 4 - methyl - phthalimide - N - oxyl, 4 - carboxy - phthalimide - N - oxyl, naphthalene - 2,3 - dicarboximide - N - oxyl, pyromellitimide - di - N - oxyl, trihydroxyiminocyanuric acid - N - oxyl, trihydroxyiminocyanuric acid - di - N - oxyl and trihydroxyiminocyanuric acid - tri - N - oxyl, etc. can be mentioned.,

[0058] The redox compound (B) is preferably a compound represented by the following formula (4). In formula (4), R ５ , R ６ , R ７ and R ８ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. At least one of R ５ and R ６ is an alkyl group having 1 to 6 carbon atoms, and R ７ and R８ At least one of them represents an alkyl group having 1 to 6 carbon atoms. R ５ and R ６ may be bonded to each other to form a cyclic structure, and R ７ and R ８ may be bonded to each other to form a cyclic structure. R １２ represents a hydrogen atom or a substituent, and n represents 0 or 1.

[0059] It is more preferable that three or more of the R ５ to R ８ are alkyl groups having 1 to 6 carbon atoms, and it is even more preferable that all four are alkyl groups having 1 to 6 carbon atoms. That is, the compound represented by the formula (4) is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group. Further, the compound is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group, or a compound having a group in which one hydrogen atom is eliminated from this compound. It is considered that the compound in which two quaternary carbons are bonded to the N-oxy radical group can suppress the N-oxy radical group from extracting a hydrogen radical from the carbon adjacent to the N-oxy radical group and decomposing the N-oxy radical group. Therefore, it is considered that the compound can more suitably adsorb and release an acidic gas. For this reason, by including such a compound in the resin composition, the acidic gas absorption rate of the resin composition becomes good.

[0060] Examples of compounds represented by formula (4) include 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidine-4-yloxy)xylene, 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl, poly(ethylene glycol)-bis-2,2,6,6-tetramethylpiperidinyl oxy radical, 2,2,6,6-tetramethylpiperidinyl oxy radical (TEMPO), and 4-hydroxy-2,2,6,6-tetramethylpiperidinyl Oxy radical, 4-amino-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-carboxy-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-methoxy-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-oxo-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-acetamido-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-octyloxy-2,2,6,6-tetramethylpiperidinyl Acryloyloxy radical, 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 3-acryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 3-methacryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 4-vinylyloxy-2,2,6,6-tetramethylpiperidinyloxy radical and 4 Examples include -vinyloxy-2,2,5,5-tetramethylpyrrolidine-oxy radical, 2,2,5,5-tetramethylpyrrolidine-oxy radical, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-oxy radical, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-oxy radical, 2,2,6,6-tetramethylmorpholine-N-oxy radical, and 2,2,6,6-tetramethylmorpholinepiperazine-N-oxy radical.

[0061] The compound represented by formula (4) is preferably 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO), 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, or 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, and more preferably 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, among the examples of compounds above. The compound may be used alone or in combination of two or more.

[0062] The compound represented by any of the above formulas (1), (2), or (4) may be a compound obtained by a predetermined synthesis method, or it may be a commercially available product. The above synthesis method is not particularly limited as long as it is a method that can obtain the compound represented by any of the above formulas (1), (2), or (4), but examples include a method of oxidizing the amino group of a disubstituted amine compound to nitroxide it. In this method, the resin composition may contain an unoxidized disubstituted amine compound corresponding to the N-oxy radical compound represented by formula (4).

[0063] In the resin composition of the third embodiment, the total content of polymer (A) and redox compound (B) is preferably 75 to 100% by mass based on 100% by mass of the resin composition. The lower limit of the total content of polymer (A) and redox compound (B) may be 80, 85, or 90% by mass, and the upper limit may be 99.9, 99.8, 99.5, or 99% by mass. When the total content of polymer (A) and redox compound (B) is 75% by mass or more, the separation rate of acidic gases from the component using the resin composition is improved.

[0064] In the resin composition of the third embodiment, the ratio of polymer (A) to redox compound (B) is preferably 99.9:0.1 to 70:30, more preferably 99.8:0.2 to 75:25, even more preferably 99.7:0.3 to 80:20, and particularly preferably 99.5:0.5 to 85:15. The ratio can be measured by GPC, various high-performance liquid chromatography (HPLC) including ion chromatography, etc. When the ratio is between 99.9:0.1 and 70:30, the durability and concentration of separated acidic gases are good when the separation of acidic gases of a component using the resin composition is repeatedly performed.

[0065] 1-3. Other Polymers and Additives The resin composition of the third embodiment may contain other polymers and additives in addition to polymer (A) and redox compound (B).

[0066] There are no particular restrictions on polymers other than polymer (A), but polymers with electrochemically stable structures are preferred. Examples of such polymers include polyvinyl alcohol (PVA) polymers. PVA polymers are polymers having vinyl alcohol units, and examples include unmodified PVA and modified PVA. Here, unmodified PVA refers to a polymer obtained by saponifying a homopolymer of vinyl esters, or a polymer obtained by saponifying a copolymer of two or more vinyl esters. Modified PVA refers to PVA in which at least a part of the molecular ends, main chain, and side chains of the unmodified PVA are substituted with reactive groups (including crosslinking), and PVA obtained by saponifying a copolymer of a vinyl ester and another ethylenically unsaturated monomer, or PVA that falls under both categories. Among these, unmodified PVA is preferred for PVA polymers.

[0067] Examples of additives include inorganic fillers, softeners, heat aging inhibitors, antioxidants, hydrolysis inhibitors, light stabilizers, antistatic agents, mold release agents, flame retardants, foaming agents, pigments, dyes, whitening agents, UV absorbers, lubricants, thickeners, and viscosity reducers. When using the above additives, the amount of additives in the resin composition of the third embodiment can be appropriately determined according to the desired physical properties of the resin composition.

[0068] 2. Method for Producing the Resin Composition The method for producing the resin composition of the third embodiment is not particularly limited and can be produced by various methods. For example, it can be produced by mixing the polymer (A), the redox compound (B), and one or more optional components as needed by known methods such as mixing in a solvent. Also, if the redox compound (B) is obtained as a by-product generated in the process of producing the polymer (A), the resin composition of the third embodiment may be produced by producing a mixture containing the polymer (A) and the redox compound (B) without separating and purifying the polymer (A) and the redox compound (B). That is, for example, the resin composition of the third embodiment may be produced by a production method including the following steps (i) and (ii): (i) a step of polymerizing a monomer mixture containing a secondary amino group monomer with a polymerization conversion rate of 99.9% or less; (ii) a step of oxidizing the polymer and monomer mixture obtained in step (i) to nitroxide the secondary amino groups of the polymer and monomer, respectively. According to this method, the content of redox compound (B) can be calculated from the polymerization conversion rate of polymer (A) and the oxidation reaction conversion rate in step (ii). Furthermore, if redox compound (B) is added to the resin composition later, the amount added can be taken into consideration when determining the content.

[0069] An example of a process for polymerizing a monomer mixture containing a secondary amino group-containing monomer is described below. However, the method for producing a polymer containing a secondary amino group-containing monomer unit is not limited to the method described below, and various methods can be used for synthesis.

[0070] When producing the resin composition of the third embodiment by the manufacturing method including steps (i) and (ii) described above, the content of redox compound (B) in the resin composition can be adjusted by the polymerization conversion rate in step (i) and the oxidation reaction conversion rate in step (ii). Alternatively, the content of redox compound (B) may be adjusted by adding and mixing redox compound (B) separately during or after steps (i) and (ii). Alternatively, the content of redox compound (B) may be adjusted by adding and mixing polymer (A) and, if necessary, one or more optional components during or after steps (i) and (ii).

[0071] The resin composition of the third embodiment can be used for various applications. The resin composition of the third embodiment contains a polymer (A) having N-oxy radical groups with Mw of 10,000 to 500,000 in its molecule, and a specific amount of a redox compound (B) with a molecular weight of less than 1,000. Therefore, it is suitable as an electrode active material for secondary batteries such as lithium-ion batteries, and as a raw material for components of electrochemical devices for separating acidic gases such as carbon dioxide. It is also suitable for various sensors and electronic devices that utilize oxidation-reduction reactions.

[0072] [Fourth Embodiment] The resin composition of the fourth embodiment contains polymer (A) of the first embodiment. The content of polymer (A) of the fourth embodiment in 100% by mass of the resin composition of the fourth embodiment can be appropriately designed depending on the application. From the viewpoint of obtaining a resin composition that has excellent repeated durability in separating acidic gases and excellent radical stability in high-temperature environments when used in electrochemical separation applications, it is preferable that polymer (A) be contained in the resin composition of the fourth embodiment at 70 to 100% by mass. The lower limit of the polymer (A) content is more preferably 75% by mass, even more preferably 80% by mass, and even more preferably 85% by mass. The upper limit of the polymer (A) content is more preferably 99.9% by mass, even more preferably 99.8% by mass, even more preferably 99.7% by mass, and particularly preferably 99.5% by mass. Note that 100% by mass of polymer (A) means a resin composition consisting only of polymer (A) except for components that are inevitably included.

[0073] The resin composition of the fourth embodiment may contain, in addition to polymer (A), other polymers, redox compounds (B), and additives.

[0074] There are no particular restrictions on polymers other than polymer (A), but polymers with an electrochemically stable structure are preferred, and the contents described in the third embodiment as a preferred example of such a polymer are similarly applied in the fourth embodiment.

[0075] The redox compound (B) in the fourth embodiment is a compound that can undergo repeated reduction and oxidation reactions, as described in the third embodiment, and is a compound with a molecular weight of less than 1000, excluding polymer (A).

[0076] The content of redox compound (B) is preferably 0.1 to 30% by mass based on 100% by mass of the resin composition of the fourth embodiment. The lower limit of the content of redox compound (B) is more preferably 0.2% by mass, even more preferably 0.3% by mass, and even more preferably 0.5% by mass. The upper limit of the content of redox compound is preferably 25% by mass, more preferably 20% by mass, and even more preferably 15% by mass. The technical reasons why the content of redox compound (B) in the resin composition of the fourth embodiment is preferably within the above range are the same as in the third embodiment.

[0077] The preferred range of molecular weight for redox compound (B) and the technical reasons for this are the same as in the third embodiment. That is, the molecular weight of redox compound (B) is less than 1000, preferably 900 or less, more preferably 800 or less, even more preferably 700 or less, and even more preferably 600 or less.

[0078] The structure of the redox compound (B) is not particularly limited, as in the third embodiment, and a preferred example is that the contents described in the third embodiment are also applied to the fourth embodiment.

[0079] The redox compound is preferably the compound represented by formula (4) described in the third embodiment, and the description of formula (4) is the same as that of the third embodiment and applies to the fourth embodiment as well.

[0080] In the fourth embodiment, the description of the preferred range for the total content of polymer (A) and redox compound (B) and the ratio of polymer (A) to redox compound (B) in the resin composition is the same as that described in the third embodiment and applies to the fourth embodiment as well.

[0081] The additives described in the third embodiment are also applicable in the fourth embodiment.

[0082] The method for producing the resin composition in the fourth embodiment is the same as described in the third embodiment.

[0083] [Fifth Embodiment] The resin composition of the fifth embodiment contains polymer (A) of the second embodiment. The content of polymer (A) of the second embodiment in 100% by mass of the resin composition of the fifth embodiment can be appropriately designed depending on the application. From the viewpoint of obtaining a resin composition that has excellent repeated durability in separating acidic gases and excellent radical stability in high-temperature environments when used in electrochemical separation applications, the content of polymer (A) of the second embodiment in 100% by mass of the resin composition of the fifth embodiment is preferably 70 to 99.9% by mass. The lower limit of the polymer (A) content is more preferably 75% by mass, even more preferably 80% by mass, and even more preferably 85% by mass. The upper limit of the polymer (A) content is more preferably 99.8% by mass, even more preferably 99.7% by mass, and even more preferably 99.5% by mass. When the polymer (A) content is 70 to 99.9% by mass, the carbon dioxide separation rate of the component using the resin composition is good, and the durability when carbon dioxide separation is repeated is good.

[0084] The resin composition of the fifth embodiment may contain, in addition to polymer (A), other polymers, redox compounds (B), and additives.

[0085] There are no particular restrictions on polymers other than polymer (A), but polymers with an electrochemically stable structure are preferred, and the contents described in the third embodiment are similarly applied to the fifth embodiment as preferred examples of such polymers.

[0086] The redox compound (B) in the fifth embodiment is a compound that can undergo repeated reduction and oxidation reactions, as described in the third embodiment, and is a compound with a molecular weight of less than 1000, excluding polymer (A).

[0087] In the fifth embodiment, the content of redox compound (B) is preferably 0.1 to 30% by mass based on 100% by mass of the resin composition of the fifth embodiment. The lower limit of the redox compound content is more preferably 0.2% by mass, even more preferably 0.3% by mass, and even more preferably 0.5% by mass. The upper limit of the redox compound content is preferably 25% by mass, more preferably 20% by mass, and even more preferably 15% by mass. The technical significance of the above content is the same as that described in the third embodiment and applies to the fifth embodiment as well. Furthermore, the description of the molecular weight, structure, preferred compounds of redox compound (B), and effects of redox compound (B) is the same as that described in the third embodiment and applies to the fifth embodiment as well.

[0088] The redox compound is preferably the compound represented by formula (4) described in the third embodiment, and the description of formula (4) is the same as that of the third embodiment and applies to the fifth embodiment as well.

[0089] In the fourth embodiment, the description of the preferred range for the total content of polymer (A) and redox compound (B) and the ratio of polymer (A) to redox compound (B) in the resin composition is the same as that described in the third embodiment and applies to the fourth embodiment as well.

[0090] The additives described in the third embodiment are applied similarly.

[0091] The method for producing the resin composition of the fifth embodiment is similar to that described in the third embodiment.

[0092] The method for producing the N-oxy radical group-containing polymer (A) of the second embodiment is not particularly limited, but for example, it can be produced by a production method including the following steps (i) and (ii): (i) a step of polymerizing a monomer mixture including a secondary amino group-containing monomer; (ii) a step of oxidizing the polymer obtained in step (i) to nitroxide the secondary amino groups of the polymer.

[0093] The oxidation reaction in step (ii) is not particularly limited as long as it is an oxidation reaction that oxidizes the polymer obtained in step (i) and nitrates the secondary amino groups of the polymer, and known methods can be applied. For example, it may be an oil-water two-phase oxidation reaction using hydrogen peroxide as the oxidizing agent, tungstic acid as the catalyst, and an alkylammonium salt as the phase transfer catalyst.

[0094] When producing polymer (A) of the second embodiment by the manufacturing method including steps (i) and (ii) described above, the method for controlling the absorbance of polymer (A) is not particularly limited, but can be adjusted by, for example, the amount of oxidizing agent added, the type of oxidizing agent, the amount of catalyst added, the type of catalyst, the temperature of the oxidation reaction, the time of the oxidation reaction, the concentration of the oxidation reaction, the type of solvent for the oxidation reaction, etc.

[0095] As a method for producing the resin composition of the fifth embodiment, a polymer (A), a redox compound (B) if necessary, and one or more optional components may be mixed by known methods such as mixing in a solvent. By-products generated in the process of producing polymer (A) may be used as components of the resin composition without separation or purification. In this case, for example, the resin composition of the fifth embodiment may be produced by a production method including the following steps (iii) and (iv): (iii) A step of polymerizing a monomer mixture containing a secondary amino group monomer with a polymerization conversion rate of 99.9% or less. (iv) A step of oxidizing the polymer and monomer mixture obtained in step (iii) to nitroxide the secondary amino groups of the polymer and monomer, respectively.

[0096] When producing the resin composition of the fifth embodiment by the manufacturing method including steps (iii) and (iv), the content of redox compound (B) in the resin composition can be adjusted by the polymerization conversion rate in step (iii). Alternatively, redox compound (B) may be added and mixed separately during or after steps (iii) and (iv). Alternatively, polymer (A) and one or more optional components may be added and mixed during or after steps (iii) and (iv).

[0097] The polymer (A) of the second embodiment and the resin composition of the fifth embodiment can be used for various applications. For example, they are suitable as electrode active materials for secondary batteries such as lithium-ion batteries, and as raw materials for components of electrochemical devices for separating acidic gases such as carbon dioxide. They are also suitable for various sensors and electronic devices that utilize oxidation-reduction reactions.

[0098] 3. Acid Gas Separation Device Next, an example of applying the polymer (A) of the present disclosure to an acid gas separation device will be described. The acid gas separation device of the present disclosure comprises a pair of electrodes, at least one of which is permeable to gas, an electrolyte membrane provided between the pair of electrodes, and a voltage application unit for applying a voltage between the pair of electrodes. The electrolyte membrane has at least one of a membrane composed of the polymer (A) of the present disclosure and a membrane composed of the resin composition of the present disclosure (hereinafter also referred to as the resin composition) containing the polymer (A). That is, it contains at least one of the polymer (A) of the first and second embodiments and the compositions of the third to fifth embodiments. The electrolyte membrane may have membranes other than the aforementioned membrane. The resin composition is non-volatile, and acid gases are adsorbed by electrolytic reduction, and the adsorbed acid gases are desorbed by electrolytic oxidation. Examples of acid gases include carbon dioxide and NO ｘ (Nitrogen oxides), SO ｘ Examples include sulfur oxides and hydrogen sulfide. Examples of acidic gas separation devices are described in Japanese Patent Publication No. 2018-001131 and International Publication No. 2022 / 185903. The former requires that both electrodes of the pair be permeable to gas, while the latter requires that only one (the negative electrode) be permeable to gas.

[0099] Figure 1 shows a schematic cross-sectional view illustrating a general configuration example of an acidic gas separation device 10 according to one embodiment of the present disclosure. For example, as shown in Figure 1, the acidic gas separation device 10 comprises an electrolyte membrane 13, a first electrode 11 and a second electrode 12 that are permeable to gas and are provided on either side of the electrolyte membrane 13, and a voltage application unit 14 that applies a voltage between the first electrode 11 and the second electrode 12. The electrolyte membrane 13 is, for example, about 1 to 1000 μm thick. The electrolyte membrane may include a support.

[0100] The polymer (A) contained in the electrolyte membrane 13 adsorbs and desorbs acidic gases by electrolytic reduction and electrolytic oxidation. That is, acidic gases are adsorbed onto polymer (A) by electrolytic reduction and desorbed from the adsorbed acidic gases by electrolytic oxidation. If the electrolyte membrane 13 further contains a redox compound (B), polymer (A) and redox compound (B) adsorb and desorb acidic gases by electrolytic reduction and electrolytic oxidation. That is, acidic gases are adsorbed onto polymer (A) and redox compound (B) by electrolytic reduction and desorbed from the adsorbed acidic gases by electrolytic oxidation.

[0101] The electrolyte membrane 13 can incorporate the acidic gas even if the electrolyte solution does not readily dissolve the acidic gas, because the acidic gas binds to the reduced form of polymer (A) on the surface of the electrolyte membrane 13 through the action of the reduced form of polymer (A) binding with the acidic gas. Furthermore, when using an electrolyte solution that does not readily dissolve such acidic gases, when releasing the acidic gas from the electrolyte membrane 13, the release of the acidic gas becomes easier because the acidic gas does not readily dissolve in the electrolyte solution.

[0102] The electrolyte membrane 13 may be a membrane formed from a gel of a non-volatile liquid such as an ionic liquid. Using an electrolyte membrane made of such a gel can suppress leakage of the electrolyte that constitutes the electrolyte membrane 13. Furthermore, even if the electrolyte membrane 13 is a gel containing the electrolyte and the resin composition, as described above, it is possible to take in acidic gas on the first electrode side and release acidic gas on the second electrode side. Therefore, it is possible to suppress the inhibition of separation of acidic gas from a gas containing acidic gas due to leakage of the electrolyte, etc., and to perform the operation continuously for a longer period of time. In order to obtain an electrolyte made of such a gel, for example, a gelling agent for gelling may be added to the electrolyte, a gelled electrolyte or polymer electrolyte may be used, or the resin composition may be gelled. Examples of gelling agents include polymers, gelling agents that utilize methods such as polymer crosslinking reactions, polymerizable polyfunctional monomers, and oil gelling agents. The gelling electrolyte and polymer electrolyte are not particularly limited and include, for example, vinylidene fluoride polymers such as polyvinylidene fluoride, acrylic acid polymers such as polyacrylic acid, acrylonitrile polymers such as polyacrylonitrile, polyether polymers such as polyethylene oxide, and compounds having an amide structure in their structure. The electrolyte membrane 13 may also contain other components, as long as it does not depart from the spirit of this disclosure. By using this resin composition, an electrolyte membrane 13 with excellent repeated durability can be obtained.

[0103] As shown in Figure 1, the acidic gas separation device 10 may include a first flow path 15 through which the gas flows while in contact with the first electrode 11, and a second flow path 16 through which the gas flows while in contact with the second electrode 12. When a voltage is applied between the first electrode 11 and the second electrode 12 by the voltage application unit 14 such that the potential of the first electrode 11 becomes lower than the potential of the second electrode 12, the acidic gas is separated from the gas containing the acidic gas. In this case, the first electrode 11 becomes the electrode that takes in the acidic gas from the gas containing the acidic gas (cathode electrode), and the second electrode 12 becomes the electrode that releases the acidic gas from the electrolyte membrane 13 (anode electrode).

[0104] When a gas containing acidic gas, nitrogen, and oxygen, such as air, is supplied from the supply port 15a of the first flow path 15, the acidic gas (mainly carbon dioxide in the case of air) is discharged from the second flow path 16, and a gas with a lower acidic gas concentration (e.g., carbon dioxide concentration) than the supplied gas is discharged from the outlet 15b of the first flow path 15. Consequently, a gas with relatively higher concentrations of nitrogen and oxygen is discharged from the outlet 15b of the first flow path 15 due to the decrease in acidic gas concentration (e.g., carbon dioxide concentration).

[0105] Acidic gas contained in the gas present around the first electrode 11 permeates through the first electrode 11 and comes into contact with the surface of the electrolyte membrane 13 (the surface on the first electrode 11 side). At this time, the voltage applied by the voltage application unit 14 causes the polymer (A) contained in the electrolyte membrane 13 to be electrolytically reduced and become a reduced form on the side closer to the first electrode 11. The acidic gas that comes into contact with the surface of the electrolyte membrane 13 (the surface on the first electrode 11 side) combines with this reduced form and is incorporated into the electrolyte membrane 13. Therefore, the incorporation of acidic gas towards the first electrode 11 side is promoted. On the other hand, the voltage applied by the voltage application unit 14 causes the reduced form of polymer (A) contained in the electrolyte membrane 13 to be electrolytically oxidized and become a radical or oxidized form on the side closer to the second electrode 12. Therefore, when the polymer (A) to which the acidic gas has been combined flows in the electrolyte membrane 13 from the side closer to the first electrode 11 to the side closer to the second electrode 12, the acidic gas that was combined with the polymer (A) is detached from the polymer (A). In other words, even if an acidic gas is bound to the reduced form of polymer (A), when the polymer (A) to which the acidic gas is bound is electrolytically oxidized on the side closer to the second electrode 12, the acidic gas is detached from the polymer (A). Therefore, when the acidic gas is bound to polymer (A) on the side closer to the first electrode 11, and then the polymer (A) to which the acidic gas is bound flows through the electrolyte membrane 13 to the side closer to the second electrode 12, the acidic gas is detached from polymer (A) on the side closer to the second electrode 12. The acidic gas detached from polymer (A) is then released from the surface of the electrolyte membrane 13 (the surface on the side closer to the second electrode 12) and permeates through the second electrode 12. It is considered that, through the binding and detachment of acidic gas to and from polymer (A) as described above, the acidic gas separation device 10 can take in acidic gas on the first electrode 11 side and release acidic gas on the second electrode side. Furthermore, if redox compound (B) is included, it is thought that redox compound (B) will produce similar effects in addition to the polymer (A) described above.

[0106] On the other hand, if the separation of acidic gases from a gas containing acidic gases is performed continuously (continuous operation), the diffusion of redox substances constituting the electrolyte membrane, or segregation due to self-aggregation of redox substances on the surface or inside the membrane via electrophoresis, may hinder the separation of acidic gases. In contrast, in the case of the acidic gas separation device 10, by using polymer (A) as the redox substance contained in the electrolyte membrane 13, it is possible to suppress segregation due to self-aggregation through molecular chain entanglement while maintaining a good separation rate of acidic gases. Furthermore, by using an electrolyte membrane 13 containing a resin composition that combines polymer (A) as a high molecular weight component and redox compound (B) as a low molecular weight component, both molecular chain entanglement and fluidity are achieved, suppressing the aggregation structure. As a result, segregation of the resin composition within the electrolyte membrane can be suppressed. Therefore, the acidic gas separation device 10 can perform acidic gas separation repeatedly over a longer period of time.

[0107] Figure 2 shows a schematic cross-sectional view illustrating a general configuration example of an acidic gas separation device 20 during charging according to another embodiment of this invention. In this example, the separator 17 is sandwiched between two electrolyte membranes 13. The separator 17 is made of a material that can permeate the electrolyte while suppressing the permeation of redox compounds. When a voltage is applied by the voltage application unit 14 such that the potential of the first electrode 11, which is the negative electrode, becomes lower than the potential of the second electrode 12, which is the positive electrode, carbon dioxide is separated from the gas containing carbon dioxide and the device is charged. During charging, a gas containing carbon dioxide (for example, air) is circulated through the first channel 15, causing carbon dioxide to come into contact with the first electrode 11 and be adsorbed (immobilized) in the electrolyte membrane 13, thereby charging the acidic gas separation device. On the other hand, during discharge, carbon dioxide is released from the electrolyte membrane 13. In other words, during charging, the gas supplied from the first channel 15 is discharged with a reduced carbon dioxide concentration, and during discharge, the gas supplied from the first channel 15 is discharged with a higher carbon dioxide concentration than the gas supplied from the first channel 15.

[0108] Examples of devices equipped with acidic gas separation devices include air purifiers and air conditioners. By incorporating a carbon dioxide separation device, it is possible to reduce the carbon dioxide concentration in enclosed spaces such as rooms, private cars, and buses.

[0109] Other examples include carbon dioxide concentrators for separating and concentrating acidic gases in the air. By concentrating carbon dioxide, it can be used in industries such as agriculture. For example, it can be applied to promoting plant growth by concentrating carbon dioxide in the air and supplying it to greenhouses. It can also be applied to CA storage applications, such as improving the shelf life of fruits and vegetables by concentrating carbon dioxide in the air and increasing the carbon dioxide concentration in storage facilities.

[0110] In the aforementioned acidic gas separation device, the thickness of the electrolyte membrane is preferably 1 to 1,000 μm. With this configuration, acidic gas can be easily separated from a gas containing acidic gas. Furthermore, the acidic gas separation device can be easily manufactured, and even when the voltage applied between the pair of electrodes is reduced, acidic gas can be suitably separated from a gas containing acidic gas.

[0111] 4. Examples of devices equipped with an air purifier, air conditioner, and carbon dioxide concentration device or acid gas separation device include air purifiers and air conditioners. By equipping them with a carbon dioxide separation device, it is possible to reduce the carbon dioxide concentration in enclosed spaces such as rooms, private cars, and buses.

[0112] Other examples include carbon dioxide concentrators for separating and concentrating acidic gases in the air. By concentrating carbon dioxide, it can be used in industries such as agriculture. For example, it can be applied to promoting plant growth by concentrating carbon dioxide in the air and supplying it to greenhouses. It can also be applied to CA storage applications, such as improving the shelf life of fruits and vegetables by concentrating carbon dioxide in the air and increasing the carbon dioxide concentration in storage facilities.

[0113] In the aforementioned acidic gas separation device, the thickness of the electrolyte membrane is preferably 1 to 1,000 μm. With this configuration, acidic gas can be easily separated from a gas containing acidic gas. Furthermore, the acidic gas separation device can be easily manufactured, and even when the voltage applied between the pair of electrodes is reduced, acidic gas can be suitably separated from a gas containing acidic gas.

[0114] The present disclosure will now be described in more detail by illustrating the examples. However, the present disclosure is not limited by the examples.

[0115] A. The following compounds were used as raw materials in the manufacturing examples and comparative examples of polymer (A), etc. LA-87: "ADEKA Stab LA-87" manufactured by ADEKA Corporation (compound name: 2,2,6,6-tetramethyl-4-piperidyl methacrylate)

[0116] (Example 1) Under a nitrogen atmosphere, 100 parts by mass of toluene, 100 parts by mass of LA-87, and 0.76 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 90°C to dissolve uniformly. Next, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure, and the reaction was continued for 1 hour. Subsequently, a solution of 0.02 parts by mass of AIBN dissolved in 0.4 parts by mass of toluene was added under pressure, and the reaction was continued for 1 hour. This process was repeated four times. After that, the autoclave was cooled to room temperature to obtain a precursor polymer (AA-1) solution. The polymerization conversion rate was 97%.

[0117] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of precursor polymer (AA-1) solution, 73.3 parts by mass of toluene, 2.2 parts by mass of methyltri-n-octylammonium chloride, 2.3 parts by mass of sodium tungstate dihydrate, and 0.4 parts by mass of phosphoric acid in 8.7 parts by mass of ion-exchanged water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 40°C with stirring. 91.6 parts by mass of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the reaction was continued for 8 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of ion-exchanged water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing procedure was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was removed by distillation using an evaporator. The obtained solid was washed with 300 mL of water, then with 500 mL of hexane, and dried in a vacuum dryer set to 80°C for 24 hours to obtain polymer (A-1). The radical content was 4.00 mmol / g, the weight-average molecular weight (Mw) was 21,000 g / mol, and the resonance peak linewidth (ΔH) in the ESR measurement shown in Figure 3 was 1.2 mT.

[0118] (Example 2) Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of the precursor polymer (AA-1) solution obtained in Example 1, 58.3 parts by mass of toluene, 2.2 parts by mass of methyltri-n-octylammonium chloride, and 2.2 parts by mass of sodium tungstate dihydrate in 10.5 parts by mass of deionized water was added to a reactor equipped with a stirring blade, a condenser, and a dropping funnel, and the mixture was heated to 40°C with stirring. 100.6 parts by mass of 30% hydrogen peroxide solution was added dropwise over 4 hours, and the reaction was continued for 5 hours. The reactor was cooled to room temperature, stirring was stopped and the mixture was allowed to stand, and the lower layer of the reaction solution, which had separated into two layers, was removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand, and the lower layer was removed. This washing procedure was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was distilled off using an evaporator. The obtained solid was washed with 300 mL of water, then with 500 mL of hexane, and dried in a vacuum dryer set to 80°C for 24 hours to obtain polymer (A-2). The polymerization conversion rate during the polymerization of the precursor polymer was 96%, the radical content of polymer (A-2) was 3.56 mmol / g, Mw was 22,500 g / mol, and the resonance peak linewidth (ΔH) in the ESR measurement was 1.4 mT.

[0119] (Example 3) Under a nitrogen atmosphere, 100 parts by mass of toluene, 100 parts by mass of LA-87, and 0.62 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 90°C to dissolve uniformly. Next, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure, and the reaction was continued for 1 hour. Subsequently, a solution of 0.02 parts by mass of AIBN dissolved in 0.4 parts by mass of toluene was added under pressure, and the reaction was continued for 1 hour. This process was repeated four times. After that, the autoclave was cooled to room temperature to obtain a precursor polymer (AA-3) solution. The polymerization conversion rate was 97%.

[0120] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of precursor polymer (AA-3) solution, 53.8 parts by mass of toluene, 2.1 parts by mass of methyltri-n-octylammonium chloride, and 2.1 parts by mass of sodium tungstate dihydrate in 10.2 parts by mass of deionized water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 60°C with stirring. 97.7 parts by mass of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the reaction was continued for 5 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing procedure was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was removed by distillation using an evaporator. The obtained solid was washed with 300 mL of water, then with 500 mL of hexane, and dried in a vacuum dryer set to 80°C for 24 hours to obtain polymer (A-3). Polymer (A-3) had a radical content of 2.21 mmol / g, Mw of 31,200 g / mol, and a resonance peak linewidth (ΔH) of 1.5 mT in ESR measurement.

[0121] (Example 4) Polymer (A-4) was obtained in the same manner as in Example 1, except that the amount of n-octyl mercaptan used as polymerization raw material was 0.15 parts by mass and the polymerization temperature was 100°C. The polymerization conversion rate during the polymerization of the precursor polymer was 96%, the radical content was 4.13 mmol / g, Mw was 79,000 g / mol, and the resonance peak linewidth (ΔH) in the ESR measurement was 1.5 mT.

[0122] (Example 5) Polymer (A-5) was obtained in the same manner as in Example 1, except that n-octyl mercaptan was not added to the polymerization raw materials and the polymerization temperature was set to 100°C. The polymerization conversion rate during the polymerization of the precursor polymer was 94%, the radical content was 4.04 mmol / g, Mw was 295,000 g / mol, and the resonance peak linewidth (ΔH) in the ESR measurement was 1.7 mT.

[0123] (Comparative Example 1) Under a nitrogen atmosphere, 100 parts by mass of toluene, 100 parts by mass of LA-87, and 0.62 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 90°C to dissolve uniformly. Next, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure, and the reaction was continued for 1 hour. Subsequently, a solution of 0.02 parts by mass of AIBN dissolved in 0.2 parts by mass of toluene was added under pressure, and the reaction was continued for 1 hour. This process was repeated four times. After that, the autoclave was cooled to room temperature, and 100 parts by mass of water was added to the reaction solution. The solid obtained by filtration was washed with 60 parts by mass of water, and then with 100 parts by mass of hexane, and dried under reduced pressure to obtain polymer (AC-1). The polymerization conversion rate was 97%, the radical content was 0 mmol / g, and the Mw was 23,100 g / mol. No resonance peaks were observed in the 339–345 mT range in ESR measurements.

[0124] (Comparative Example 2) "2,2,6,6-tetramethylpiperidine 1-oxyl free radical (sublimation purified product)" manufactured by Tokyo Chemical Industry Co., Ltd. was evaluated as compound (AC-2) without modification. The radical content was 6.40 mmol / g, the molecular weight measured by ESI-MS was 156 g / mol, and the resonance peak linewidth (ΔH) in the ESR measurement shown in Figure 3 was 0.4 mT.

[0125] (Comparative Example 3) "4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical" manufactured by Tokyo Chemical Industry Co., Ltd. was evaluated as compound (AC-3) without modification. The radical content was 4.16 mmol / g, the molecular weight measured by ESI-MS was 240 g / mol, and the resonance peak linewidth (ΔH) measured by ESR was 0.4 mT.

[0126] (Example 11) Under a nitrogen atmosphere, 98 parts by mass of toluene, 100 parts by mass of LA-87, and 0.62 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 100°C to dissolve uniformly. Next, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure, and the reaction was continued for 1 hour. Subsequently, a solution of 0.02 parts by mass of AIBN dissolved in 0.4 parts by mass of toluene was added under pressure, and the reaction was continued for 1 hour. This process was repeated four times. After that, the autoclave was cooled to room temperature to obtain a precursor polymer (AA-11) solution. The polymerization conversion rate was 93%.

[0127] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of precursor polymer (AA-11) solution, 57.2 parts by mass of toluene, 2.0 parts by mass of methyltri-n-octylammonium chloride, and 2.1 parts by mass of sodium tungstate dihydrate in 14.8 parts by mass of deionized water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 40°C with stirring. 94 parts by mass of 30% hydrogen peroxide solution was added dropwise over 6 hours, and the reaction was continued for 3 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing procedure was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was removed by distillation using an evaporator. The obtained solid was washed with 300 mL of water, and then with 500 mL of hexane, and dried in a vacuum dryer set to 80°C for 24 hours to obtain polymer (A-11). The weight-average molecular weight (Mw) of polymer (A-11) was 22,000 g / mol, and the absorbance was 3.75.

[0128] (Example 12) Polymer (A-12) was obtained in the same manner as in Example 11, except that 80 parts by mass of LA-87 and 20 parts by mass of methyl methacrylate were used as polymerization raw materials. The polymerization conversion rate during precursor polymer polymerization was 95%, the Mw of polymer (A-12) was 24,300 g / mol, and the absorbance was 3.03.

[0129] (Example 13) Polymer (A-13) was obtained in the same manner as in Example 11, except that 66 parts by mass of 30% hydrogen peroxide solution were added dropwise over 4 hours. The polymerization conversion rate during the polymerization of the precursor polymer was 94%, the Mw of polymer (A-13) was 26,400 g / mol, and the absorbance was 2.60.

[0130] (Comparative Example 11) Polymer (A-15) was obtained in the same manner as in Example 11, except that 47 parts by mass of 30% hydrogen peroxide solution were added dropwise over 3 hours. The polymerization conversion rate during the polymerization of the precursor polymer was 92%, the Mw of polymer (A-15) was 22,500 g / mol, and the absorbance was 1.82.

[0131] (Comparative Example 12) The procedure was the same as in Example 1, except that the precursor polymer (AA-11) was used as is without undergoing an oxidation reaction. The polymerization conversion rate during polymerization of the precursor polymer (AA-16) was 92%, Mw was 22,500 g / mol, and absorbance was 0.00.

[0132] (Example 21) Under a nitrogen atmosphere, 98 parts by mass of toluene, 100 parts by mass of LA-87, and 0.62 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 100°C to dissolve uniformly. Next, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure, and the reaction was continued for 1 hour. Subsequently, a solution of 0.02 parts by mass of AIBN dissolved in 0.4 parts by mass of toluene was added under pressure, and the reaction was continued for 1 hour. This process was repeated four times. After that, the autoclave was cooled to room temperature to obtain a precursor polymer (AA-1) solution. The polymerization conversion rate was 93%.

[0133] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of precursor polymer (AA-1) solution, 57.2 parts by mass of toluene, 2.0 parts by mass of methyltri-n-octylammonium chloride, and 2.1 parts by mass of sodium tungstate dihydrate in 14.8 parts by mass of deionized water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 40°C with stirring. 94 parts by mass of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the reaction was continued for 8 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing operation was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was distilled off using an evaporator. The obtained solid was dried for 24 hours in a vacuum dryer set to 80°C to obtain resin composition (C-1). The oxidation reaction conversion rate was 93%, the content of redox compound (B-1) in 100 parts by mass of resin composition (C-1) was 6.5 parts by mass, and the weight-average molecular weight (Mw) of polymer (A-21) in resin composition (C-1) was 22,000 g / mol.

[0134] (Example 22) Resin composition (C-2) was obtained in the same manner as in Example 21, except that the amount of n-octyl mercaptan used among the polymerization raw materials was 0.2 parts by mass. The polymerization conversion rate during precursor polymer polymerization was 92%, the oxidation reaction conversion rate was 93%, the content of redox compound (B-1) in 100 parts by mass of resin composition (C-2) was 7.4 parts by mass, and the weight-average molecular weight (Mw) of polymer (A-22) contained in resin composition (C-2) was 61,000 g / mol.

[0135] (Comparative Example 21) After the washing operation was completed, the upper layer of toluene solution was removed and the toluene was removed by reprecipitation purification with 10 times the amount of methanol relative to the toluene solution, except that the resin composition (CC-1) was obtained in the same manner as in Example 21. The redox compound (B-1) content in the resin composition (C-1) was 0% by mass.

[0136] (Comparative Example 22) Under a nitrogen atmosphere, 98 parts by mass of toluene, 100 parts by mass of LA-87, and 0.62 parts by mass of n-octyl mercaptan (nOM) were placed in an autoclave equipped with a stirrer and heated to 100°C to dissolve uniformly. Then, at the same temperature, a solution of 0.02 parts by mass of azobisisobutyronitrile (AIBN) dissolved in 0.4 parts by mass of toluene was injected under pressure. After continuing the reaction for 1 hour, an additional solution of 0.02 parts by mass of AIBN dissolved in 0.4 parts by mass of toluene was injected under pressure. After continuing the reaction for 20 minutes, the autoclave was cooled to room temperature to obtain a precursor polymer (AA-1) solution. The polymerization conversion rate was 53%.

[0137] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 100 parts by mass of precursor polymer (AA-1) solution, 57.2 parts by mass of toluene, 2.0 parts by mass of methyltri-n-octylammonium chloride, and 2.1 parts by mass of sodium tungstate dihydrate in 14.8 parts by mass of deionized water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 40°C with stirring. 94 parts by mass of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the reaction was continued for 8 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing operation was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the extracted lower layer (aqueous layer) was 0.2 mg / L or less, the toluene solution in the upper layer was removed, and the toluene was distilled off using an evaporator. The obtained solid was dried for 24 hours in a vacuum dryer set to 80°C to obtain the resin composition (CC-2). The oxidation reaction conversion rate was 91%, the content of redox compound (B-1) in 100 parts by mass of the resin composition (CC-2) was 42.8 parts by mass, and the weight-average molecular weight (Mw) of polymer (A-21) in the resin composition (CC-2) was 22,000 g / mol.

[0138] (Comparative Example 23) Under a nitrogen atmosphere, 100 parts by mass of LA-87 and 860 parts by mass of toluene were placed in an autoclave equipped with a stirrer and heated to 110°C to dissolve uniformly. Then, at the same temperature, a solution of 1.32 parts by mass of 2,2'-azobis-2,4-dimethylvaleronitrile dissolved in 6 parts by mass of toluene was injected under pressure. After continuing the reaction for 3 hours, the autoclave was cooled to room temperature, and the resulting solution was reprecipitated and purified with 10 times the volume of methanol to remove unreacted LA-87, and dried under reduced pressure to obtain a precursor polymer (AA-3).

[0139] Under a nitrogen atmosphere, an aqueous solution prepared by dissolving 30 parts by mass of precursor polymer (AA-3), 127.2 parts by mass of toluene, 2.0 parts by mass of methyltri-n-octylammonium chloride, and 2.1 parts by mass of sodium tungstate dihydrate in 14.8 parts by mass of deionized water was added to a reactor equipped with a stirring blade, condenser, and dropping funnel, and the mixture was heated to 40°C with stirring. 94 parts by mass of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the reaction was continued for 8 hours. The reactor was cooled to room temperature, stirring was stopped, and the mixture was allowed to stand. The lower layer of the reaction solution, which had separated into two layers, was then removed. 63 parts by mass of deionized water was added to the reactor, and after stirring for 15 minutes, stirring was stopped and the mixture was allowed to stand. The lower layer was then removed. This washing operation was repeated at least three times, and after confirming with test paper that the hydrogen peroxide concentration in the removed lower layer (aqueous layer) was 0.2 mg / L or less, the upper layer of toluene solution was removed. To 157.2 parts by mass of the toluene solution, 1.6 parts by mass of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinooxyl was added as the redox compound (B-1), and then the toluene was removed by distillation using an evaporator. The resulting solid was dried for 24 hours in a vacuum dryer set to 80°C to obtain resin composition (CC-3). The weight-average molecular weight (Mw) of polymer (A-23) in resin composition (CC-3) was 2,000 g / mol.

[0140] B. Measurement of physical properties, etc. (Weight-average molecular weight (Mw), molecular weight distribution (Mw / Mn)) A sample solution was prepared by dissolving 12 mg of a 30% by mass toluene solution of the polymer (A-1) obtained in Example 1 in 5 mL of tetrahydrofuran. The column oven temperature was set to 40°C, and 20 μL of the sample solution was injected into the apparatus at an eluent flow rate of 0.35 mL / min, and the chromatogram was measured. Ten standard polystyrene samples with molecular weights in the range of 400 to 5,000,000 were subjected to GPC measurement, and a calibration curve showing the relationship between retention time and molecular weight was created. Based on this calibration curve, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the resin to be measured were determined. Note that Mn is the number-average molecular weight. Apparatus: Tosoh Corporation GPC instrument HLC-8320 Separation column: Tosoh Corporation TSKguardcolumnSuperHZ-H, TSKgelHZM-M, and TSKgelSuperHZ4000 connected in series Eluent: Tetrahydrofuran eluent Flow rate: 0.35 mL / min Column temperature: 40°C Detection method: Differential refractive index (RI) Measurements were performed similarly for other examples and comparative examples. However, since the compounds (AC-2) and (AC-3) of Comparative Examples 2 and 3 are not polymers, the molecular weights shown are those measured by electrospray ionization mass spectrometry (ESI-MS).

[0141] (Polymerization conversion rate) For the polymers of Examples 1 to 5 and Comparative Example 1, 1 mg of the reaction mixture after the polymerization reaction was dissolved in 2 mL of deuterated chloroform. １ ¹H-NMR was measured to determine the integral value (IM) of protons (6.0–6.2 ppm) of the vinyl double bond of the LA-87 monomer and the integral value (IP) of protons (5.0–5.3 ppm) adjacent to the methine carbon in the side chain of the polyLA-87 polymer. The polymerization conversion rate was then calculated using the following formula: Polymerization conversion rate (%) = [IP / (IM + IP)] × 100. Similar measurements were performed for other examples and comparative examples.

[0142] (Electron Spin Resonance Measurement) 0.08 mg each of the polymers and compounds (hereinafter also referred to as polymers, etc.) from Examples 1-5 and Comparative Examples 1-3 were weighed out and dissolved in 0.5 mL of toluene to prepare a sample solution with a concentration of 0.02% by mass. The sample solution was placed in a glass tube for ESR measurement and set in an ESR measuring device (BRUKER EMX-nano), and ESR measurement was performed under the following conditions. Note that the appearance of the resonance peak at a magnetic field strength of 339-345 mT is sufficient if the maximum value is included, and the minimum value may be outside the range of the magnetic field strength. Frequency: 9.65 GHz Modulation Amplitude: 1 G Time Constant: 1.28 mS Sweep Time: 30 s Microwave Power: 0.3 mW Center Field: 344 mT Sweep Width: ±20 mT For the resonance peaks originating from radicals appearing at magnetic field strengths of 339 to 345 mT on the magnetic field strength-signal strength spectrum obtained by ESR measurement, the magnetic field strengths showing the maximum and minimum of the signal strength were read, and the difference between these two magnetic field strengths was calculated to determine the resonance peak linewidth (ΔH). In cases where splitting of the resonance peak originating from the hyperfine structure of the radical was observed, the linewidth was determined by reading the magnetic field strengths of the maximum and minimum pair of the split peaks, which were the central peaks. The appearance of the resonance peak at a magnetic field strength of 339-345 mT means that the maximum value is included within this range, and the minimum value may be outside the aforementioned magnetic field strength range.

[0143] (Absorbance) To 1.5 g of a 30% by mass toluene solution of the polymer used in Example 11 (A-11), the polymer used in Comparative Example 11 (A-15), and the polymer used in Comparative Example 12 (AA-16), 3.0 g of toluene was added to prepare a 10% by mass sample solution. This solution was poured into a 1 cm × 1 cm × 3 cm quartz glass cell, and the absorbance at 470 nm was measured using a UV-3600 ultraviolet-visible-infrared spectrophotometer (Shimadzu Corporation).

[0144] (Oxidation reaction conversion rate) The oxidation reaction conversion rate was calculated by a chemical titration method based on redox reactions (redox titration method). Specifically, 100 mg each of resin compositions (C) or (CC) from Examples 21, 22 and Comparative Examples 21-23 was weighed out, dissolved in chloroform and acetic acid, and then a 0.2 N potassium iodide aqueous solution was added. The liberated iodine was back-titrated with a 0.05 N sodium thiosulfate aqueous solution to calculate the oxidation reaction conversion rate. Two samples were analyzed for the test, and the average value was taken as the oxidation reaction conversion rate.

[0145] C. Evaluation (Radical Content) The radical content of the polymers, etc., in each of the above examples was calculated by chemical titration based on redox reactions (redox titration). Specifically, 1 g of the polymer, etc., in each example was weighed out, dissolved in chloroform and acetic acid, and then a 0.2 N potassium iodide aqueous solution was added. The liberated iodine was back-titrated with a 0.05 N sodium thiosulfate aqueous solution to determine the radical content (mol / g) in the polymer, etc., in each example. The test was performed on two samples, and the average value was used as the analytical value.

[0146] (Radical Stability (Radical Content and Radical Retention Rate after Heat Resistance Test)) In each of the above examples, 100 mg of the polymer, etc., was weighed out, placed in a glass test tube, and heated in an explosion-proof oven set to 100°C under atmospheric conditions for 16 hours. After removing from the explosion-proof oven and cooling to room temperature, the radical content after the heating test was determined using the method described in "Radical Content" above. The radical retention rate (%) was then calculated from the ratio of the radical content before and after heating (radical content after heating test / radical content before heating test).

[0147] (Film-forming properties) 5 g of each polymer was mixed with 20 g of toluene and stirred with a magnetic stirrer for 30 minutes. The resulting solution was applied to a PET film using a stainless steel applicator with a clearance of 200 μm and heated and dried in a box-type dryer set to 100°C for 1 hour. The resulting film was peeled from the PET film and observed with an optical microscope to determine the number of defects in a 100 mm × 100 mm area. Film-forming properties were determined according to the following criteria: ++: fewer than 10 defects. +: 10 to 100 defects. NG: more than 100 defects.

[0148] C-1. Preparation of evaluation cells <Electrolyte membrane> 100.0 g of dimethylformamide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was mixed with 6.5 g of poly(vinylidene fluoride-co-hexafluoropropylene) (manufactured by Sigma-Aldrich) and stirred at 80°C for 3 hours until dissolved. Next, 24.0 g of polymer (A-1) from Example 1 was added to the resulting solution and stirred at 80°C for 3 hours until dissolved. Next, 12.9 g of ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (emimFSI, manufactured by Sigma-Aldrich)] was added to the resulting solution, heated to 40°C, and stirred for 3 hours. Using the liquid thus obtained, a liquid film with a thickness of 230 μm was prepared on a glass plate using an applicator and dried under reduced pressure at 60°C for 8 hours. The dried film obtained by the above drying was peeled off the glass plate. By doing so, a dried film with a thickness of 100 μm was obtained. This obtained dried film was cut to a size of 20 mm in length and 24 mm in width and used as an electrolyte membrane. In the other examples and comparative examples, electrolyte membranes and electrodes described later were prepared by the same method. However, in Example 21, the "polymer of Example 1 (A-1)" described above shall be read as "resin composition of Example 21 (C-1)". In Examples 22 and Comparative Examples 21 to 23, the corresponding resin compositions shall be read as such.

[0149] <Electrodes> Carbon paper (TGP-H-030 manufactured by Toray Industries, Inc.) was cut to a size of 20 mm (length) x 20 mm (width) x 0.1 mm (thickness), and conductive copper foil tape was attached to one side. Two of these were prepared and used as the cathode electrode and anode electrode. <Flow Channels> A polytetrafluoroethylene resin plate was cut to a size of 50 mm (length) x 50 mm (width) x 5 mm (thickness), and two holes were made in appropriate places. A groove measuring 1 mm deep x 20 mm (length) x 20 mm (width) was carved into this cut resin plate, connecting to the aforementioned holes. Two of these were prepared and used as the first flow channel and the second flow channel.

[0150] <Evaluation Cell> The electrolyte membrane, electrodes, and channels of Example 1 were assembled to form the structure shown in Figure 1, and a power supply, which acts as a voltage application unit, was connected to the conductive copper foil tape of the electrodes. In this way, an evaluation cell with the structure shown in Figure 1 was fabricated. Evaluation cells were similarly fabricated for the other examples and comparative examples.

[0151] C-2. CO ２ Evaluation of Separation Speed ​​The evaluation cell was placed in an environment of 25°C. A 1L gas bag filled with carbon dioxide to a carbon dioxide concentration of 2000 ppm and an air pump were installed in the hole of the flow path on the cathode electrode side, so as to circulate within the flow path on the cathode electrode side. Similarly, a 1L gas bag filled with carbon dioxide to a carbon dioxide concentration of 400 ppm and an air pump were installed in the hole of the flow path on the anode electrode side, so as to circulate within the flow path on the anode electrode side. The carbon dioxide concentration was measured using a portable carbon dioxide concentration meter (FUSO-77535 manufactured by FUSO Corporation) placed inside each air bag. A voltage of 4.0V was applied between the electrodes by adjusting the power supply. After applying the voltage, the gas in the gas bags was circulated at a flow rate of 200 mL / min through the flow paths of each electrode using the air pumps installed in the flow paths on the cathode electrode side and the anode electrode side. By doing so, the gas in the gas bag was continuously passed through the flow paths of each electrode at a flow rate of 200 mL / min. For Examples 1-5, Comparative Examples 1-3, Examples 11-13, and Comparative Examples 11 and 12, the carbon dioxide concentration (C) in the flow path on the cathode electrode side 60 minutes after voltage application was measured. ６０ ) was measured. On the other hand, for Examples 21 and 22 and Comparative Examples 21 to 23, the carbon dioxide concentration (C) in the channel on the cathode electrode side was measured 20 minutes, 50 minutes, and 100 minutes after voltage application. ２０ , C ５０ , C １００ ) was measured.

[0152] C-3. CO ２ For the separation performance maintenance rate of Examples 1 to 5 and Comparative Examples 1 to 3, the CO ２ The separation rate was evaluated a total of 10 times, and the carbon dioxide concentration (C) in the channel on the cathode electrode side after 60 minutes in the 10th evaluation was measured. ６０－１０) was measured. CO was calculated using the following formula. ２ The separation performance maintenance rate was calculated. ２ Separation performance maintenance rate (%) = [(2000-C ６０－１０ ) / (2000-C ６０ ) ] × 100 On the other hand, for Examples 21 and 22 and Comparative Examples 21 to 23, the CO ２ After performing one evaluation of the separation speed, the same evaluation cell is used to obtain the CO ２ The separation rate was evaluated again, and the carbon dioxide concentration (C) in the channel on the cathode electrode side was measured after 100 minutes. １００－２ ) was measured. Based on the following formula, CO ２ The separation performance maintenance rate was calculated. ２ Separation performance maintenance rate (%) = [(2000-C １００－２ ) / (2000-C １００ )] × 100

[0153] C-4. Bleed-out resistance of the CO ２ In evaluating the separation rate, the prepared electrolyte membrane was cut to a size of 50 mm (length) x 50 mm (width) x 100 μm (thickness) and heated in an explosion-proof oven at 70°C for 10 hours. The surface of the heated electrolyte membrane was then wiped with a cloth, and the bleed-out resistance was evaluated according to the following criteria: +: The weight change of the cloth before and after wiping is less than 10 mg. NG: The weight change of the cloth before and after wiping is 10 mg or more.

[0154] The physical properties and evaluation results for each example are shown in Tables 1 to 3.

[0155]

[0156]

[0157] Polymers (A) of Examples 1 to 5 exhibit excellent radical stability in high-temperature environments, and CO ２ When used as an active ingredient in a separation device, CO2 after repeated testing ２ It exhibits excellent separation performance retention. On the other hand, compounds in which no resonance peaks are observed in ESR measurements are, as shown in Comparative Example 1, CO ２It was confirmed that the compounds did not function as active ingredients in the separation device. Furthermore, compounds with a resonance peak linewidth of less than 0.8 mT in ESR measurements showed CO2 emissions after repeated testing, as shown in Comparative Examples 2 and 3. ２ It was confirmed that the separation performance retention rate was inferior.

[0158] Furthermore, the polymer (A) shown in Examples 11 to 13 is CO ２ When used as an active ingredient in a separation device, CO ２ The separation rate was confirmed to be good. On the other hand, the polymers or precursor polymers with an absorbance of less than 2.00 as described above were CO ２ It was confirmed that the separation speed was inferior.

[0159] Furthermore, as shown in Table 3, the resin composition of the third embodiment is CO ２ When used as an active ingredient in a separation device, CO ２ The separation rate was good, and CO after repeated testing ２ It was confirmed that the resin composition exhibited excellent separation performance retention and good bleed-out resistance when present as a component in the electrolyte membrane. On the other hand, as shown in Comparative Example 21, the resin composition without redox compound (B) was found to have a lower performance retention rate compared to Examples 21 and 22. Furthermore, as shown in Comparative Example 22, the resin composition with a redox compound (B) content exceeding 30% by mass was found to have problems with bleed-out resistance. In addition, as shown in Comparative Example 23, the resin composition with a weight-average molecular weight of less than 10,000 was found to have poor performance retention and bleed-out resistance.

[0160] This application claims priority based on Japanese Patent Application No. 2025-007089 filed on 17 January 2025, Japanese Patent Application No. 2025-027730 filed on 25 February 2025, and Japanese Patent Application No. 2025-027736 filed on 25 February 2025, and incorporates all of their disclosures herein.

[0161] 10: Acid gas separation device (evaluation cell), 11: First electrode, 12: Second electrode, 13: Electrolyte membrane, 14: Voltage application section, 15: First channel, 16: Second channel, 17: Separator, 20: Acid gas separation device

Claims

1. An N-oxy radical group-containing polymer having an N-oxy radical group within its molecule, measured using an electron spin resonance spectrometer in a 0.02% by mass solution with toluene as the solvent, the linewidth (ΔH) of the resonance peak originating from an organic radical appearing at a magnetic field strength of 339–345 mT is 0.8–3.0 mT.

2. An N-oxy radical group-containing polymer having an N-oxy radical group in its molecule, measured in a 10% by mass solution with toluene as the solvent, in a quartz glass cell with a path length of 1 cm, with an absorbance of 2.00 to 4.20 at a wavelength of 470 nm.

3. A resin composition comprising a polymer (A) having an N-oxy radical group in its molecule and a redox compound (B) with a molecular weight of less than 1000, wherein the weight-average molecular weight of polymer (A), determined by gel permeation chromatography on a standard polystyrene basis, is 10,000 to 500,000, and the content of redox compound (B) is 0.1 to 30% by mass.

4. The resin composition according to claim 3, wherein polymer (A) is the N-oxy radical group-containing polymer according to claim 1.

5. The resin composition according to claim 3, wherein polymer (A) is the N-oxy radical group-containing polymer according to claim 2.

6. The resin composition according to claim 3, wherein polymer (A) contains N-oxy radical group-containing monomer units, and the content of the N-oxy radical group-containing monomer units relative to the total mass of all structural units constituting polymer (A) is 50 to 100% by mass.

7. The resin composition according to claim 3, wherein the redox compound (B) is a redox compound having an N-oxy radical group in its molecule.

8. The resin composition according to claim 7, wherein the redox compound (B) is a compound represented by the following formula (4). (In formula (4), R ５ , R ６ , R ７ and R ８ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. At least one of R ５ and R ６ is an alkyl group having 1 to 6 carbon atoms, and at least one of R ７ and R ８ represents an alkyl group having 1 to 6 carbon atoms. R ５ and R ６ may be bonded to each other to form a cyclic structure, and R ７ [[ID=2W]] and R ８ may be bonded to each other to form a cyclic structure. R １２ represents a hydrogen atom or a substituent, and n represents 0 or 1.) 9. A resin composition containing the N-oxy radical group-containing polymer described in claim 1.

10. A resin composition containing the N-oxy radical group-containing polymer described in claim 2.

11. An acid gas separation device comprising: a pair of electrodes, at least one of which is permeable to gas; an electrolyte membrane provided between the pair of electrodes; and a voltage application unit for applying a voltage between the pair of electrodes, wherein the electrolyte membrane contains an N-oxy radical group-containing polymer according to claim 1 or 2, or a resin composition according to any one of claims 3 to 10, and the N-oxy radical group-containing polymer or the resin composition is electrolytically reduced to adsorb an acid gas, and the adsorbed acid gas is desorbed by electrolytic oxidation.

12. An air purifier equipped with the acidic gas separation device described in claim 11.

13. An air conditioner comprising the acid gas separation device described in claim 11.

14. A carbon dioxide concentration apparatus comprising the acid gas separation device described in claim 11.

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