Ion exchange resin, electrode forming composition, electrode, anode for water electrolysis apparatus, membrane electrode assembly, and water electrolysis apparatus

Abstract

The present invention provides an ion exchange resin that enables the realization of highly durable electrodes, an electrode-forming composition containing this ion exchange resin, an electrode, an anode for a water electrolysis apparatus, a membrane electrode assembly, and a water electrolysis apparatus. [Solution] According to one aspect, an ion exchange resin is provided. The ion exchange resin has an ion exchange capacity of 0.30 meq. / g or more and 0.80 meq. / g or less. The ion exchange resin has a block copolymer structure of styrene-ethylene-butylene-styrene. According to one aspect, an electrode-forming composition is provided. The electrode-forming composition comprises the ion exchange resin, catalyst, and solvent according to the other aspect.

Description

[Technical Field] 【0001】 The present invention relates to an ion exchange resin, an electrode forming composition, an electrode, an anode for a water electrolysis apparatus, a membrane electrode assembly, and a water electrolysis apparatus. [Background technology] 【0002】 As a method for producing hydrogen, water electrolysis, which generates hydrogen and oxygen gases by electrolyzing water, is being studied. Among water electrolysis methods, the AEM method, which uses an anion exchange membrane (AEM), is attracting attention because it does not require the use of expensive precious metals as catalysts. [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] Japanese Patent Publication No. 2002-367626 [Overview of the Initiative] [Problems that the invention aims to solve] 【0004】 The object of the present invention is to provide an ion exchange resin that does not require high-temperature sintering in the electrode manufacturing process and enables the realization of an electrode having a catalyst layer that is poorly soluble in electrolytes and purified water, as well as an electrode forming composition containing this ion exchange resin, an electrode, an anode for a water electrolysis apparatus, a membrane electrode assembly, and a water electrolysis apparatus. [Means for solving the problem] 【0005】 According to one aspect, an ion exchange resin is provided. The ion exchange resin has an ion exchange capacity of 0.30 meq. / g or more and 0.80 meq. / g or less. The ion exchange resin has a block copolymer structure of styrene-ethylene-butylene-styrene. 【0006】 According to one aspect, an electrode-forming composition is provided. The electrode-forming composition comprises an ion exchange resin, a catalyst, and a solvent according to the other aspect. 【0007】 According to one aspect, an electrode is provided. The electrode includes an ion exchange resin according to the other aspect. 【0008】 According to one aspect, an anode for a water electrolysis apparatus is provided. The anode for the water electrolysis apparatus includes an ion exchange resin according to the other aspect. 【0009】 According to one aspect, a membrane electrode assembly is provided. The membrane electrode assembly includes an anode containing an ion exchange resin according to the other aspect, a cathode, and an ion exchange membrane located between the anode and the cathode. 【0010】 According to one aspect, a water electrolysis apparatus is provided. The water electrolysis apparatus includes a membrane electrode assembly according to the other aspect. [Effects of the Invention] 【0011】 According to the present invention, an ion exchange resin is provided that eliminates the need for high-temperature sintering in the electrode manufacturing process and enables the realization of an electrode having a catalyst layer that is poorly soluble in electrolytes and purified water, as well as an electrode forming composition containing this ion exchange resin, an electrode, an anode for a water electrolysis apparatus, a membrane electrode assembly, and a water electrolysis apparatus. [Brief explanation of the drawing] 【0012】 [Figure 1] A schematic cross-sectional view showing an example of a water electrolysis apparatus according to the embodiment. [Modes for carrying out the invention] 【0013】 The ion exchange resin according to this embodiment has an ion exchange capacity of 0.30 meq. / g or more and 0.80 meq. / g or less, and has a styrene-ethylene-butylene-styrene block copolymer structure. Using such an ion exchange resin, it is possible to realize an electrode that has ion conductivity and sufficient mechanical strength in a water electrolysis environment. 【0014】 An electrode for water electrolysis is manufactured, for example, by coating an electrode-forming composition onto an ion-exchange membrane. The electrode for water electrolysis includes, for example, a catalyst and a binder. The electrode for water electrolysis may further include a conductive porous body. The binder is used to bind catalysts to each other, to the catalyst and the conductive porous body, and to the catalyst and the ion-exchange membrane. The ion-exchange resin according to the embodiment can be suitably used as this binder. 【0015】 First, this ion exchange resin has an ion exchange capacity of 0.30 meq. / g to 0.80 meq. / g, and therefore can function as a binder. That is, resins with an ion exchange capacity higher than 0.80 meq. / g have a high water content, so they swell when they come into contact with water, and their dimensional changes are large. If such a resin is used as a binder for water electrolysis electrodes, the resin will swell with the electrolyte, reducing its binding performance, which can lead to a decrease in electrode performance. Also, if a resin with an ion exchange capacity lower than 0.30 meq. / g is used as a binder, its low ion conductivity can increase the resistance of the electrode and raise the voltage of the water electrolysis device. Furthermore, it can cause a decrease in water electrolysis performance by hindering ion conductivity to the electrode catalyst and water transport. Therefore, ion exchange resins used in a water electrolysis environment (1% KOH, 55°C) need to have an appropriate ion exchange capacity. This ion exchange resin has an ion exchange capacity of 0.30 meq. / g to 0.80 meq. / g, which enables the creation of a catalyst layer that is poorly soluble in electrolytes and purified water, and also enables the creation of low-resistance electrodes. 【0016】 Furthermore, this ion exchange resin has a block copolymer structure of styrene-ethylene-butylene-styrene (SEBS). Therefore, when this ion exchange resin is used as a binder, sintering can be performed at a temperature of around 100°C during the electrode fabrication process. Consequently, sintering at high temperatures of 300°C or higher is unnecessary, as is the case when fluorine-based resins such as polytetrafluoroethylene are used as binders, thus improving the efficiency of electrode fabrication. 【0017】 Hereinafter, embodiments for implementing the present invention will be described in detail. 【0018】 [Ion exchange resin] The ion exchange resin according to the embodiment is composed of a styrene part into which a quaternary ammonium cation is introduced, a hydrophobic ethylene part and butylene part, and a styrene part into which no ion exchange group is introduced. 【0019】 The (number) average molecular weight of the ion exchange resin is, for example, 10,000 g / mol or more and 1,000,000 g / mol or less, preferably 50,000 g / mol or more and 300,000 g / mol or less. This (number) average molecular weight can be measured, for example, by (gel permeation chromatography: GPC). 【0020】 The ion exchange capacity of the ion exchange resin is 0.30 meq. / g or more and 0.80 meq. / g or less, preferably 0.40 meq. / g or more and 0.65 meq. / g or less. This ion exchange capacity can be measured, for example, by the method described in the examples below. 【0021】 The water content of the ion exchange resin is, for example, 10% or more and 60% or less. This water content can be measured, for example, by the method described in the examples below. 【0022】 The ion exchange resin according to the embodiment can be obtained, for example, by inducing a styrene-ethylene-butylene-styrene copolymer. Specifically, first, a part of the phenyl groups of the styrene part of the styrene-ethylene-butylene-styrene copolymer is modified with a chloromethyl group. The chlorine group is ammoniated to form a quaternary ammonium cation. Also, the ammonium is electrically neutralized by an anion. Examples of the anion include HCO3, NO3, OH, Cl, Br, I, etc., but HCO3, NO3, Cl, Br, I are preferred in terms of ease of synthesis and stability in the atmosphere. 【0023】 [Electrode] The electrode according to this embodiment can be used for hydrogen production equipment, water electrolysis equipment, fuel cells, and the like. The electrode according to this embodiment can be particularly preferably used as an anode electrode for water electrolysis equipment. 【0024】 The electrode contains an ion exchange resin according to the embodiment. The electrode may include the ion exchange resin according to the embodiment and a catalyst. The electrode may further include at least one selected from the group consisting of binders, ion conductors, and conductive agents other than the ion exchange resin according to the embodiment. The electrode may also contain other additives. The electrode may also contain a conductive porous body for supporting the catalyst. In particular, in the electrode, the mixture of the ion exchange resin, binder, ion conductor, other additives, catalyst, and conductive agent is referred to as the catalyst layer. The amount of the ion exchange resin according to the embodiment in the catalyst layer is, for example, 2.0% by mass or more and 10.7% by mass or less, and preferably 3.5% by mass or more and 9.1% by mass or less. 【0025】 A catalyst promotes oxidation or reduction reactions. Catalysts include, for example, metal catalysts, typically in particulate form. Examples of metal catalysts include elemental metals or alloys of platinum, gold, silver, palladium, iridium, ruthenium, rhodium, tin, iron, cobalt, nickel, manganese, molybdenum, tungsten, zirconium, chromium, tantalum, zirconium, aluminum, and zinc, or oxides or hydroxides containing at least one of these elements. For the anode, an alloy or oxide containing at least one of iron, cobalt, or nickel is preferable. For the cathode, a catalyst containing platinum, gold, silver, palladium, iridium, rhodium, ruthenium, tin, iron, cobalt, nickel, or manganese, or an alloy or oxide containing at least one of these metal elements, is preferable. 【0026】 The amount of catalyst used in the electrode layer is, for example, 26.8% by mass or more and 98.0% by mass or less, preferably 38.1% by mass or more and 96.2% by mass or less. 【0027】 Ion conductive agents enhance the ionic conductivity of electrodes. Examples of ion conductive agents include perfluorocarbon polymers having basic functional groups, aromatic polyether ether ketones, polysulfones, polyfluorenes, and polystyrenes. Ion exchange resins may also be used as ion conductive agents. The ion exchange resin may be the ion exchange resin according to the embodiment, or other ion exchange resins may be used. Examples of other ion exchange resins include ion exchange resins having imidazole groups. 【0028】 Conductive agents enhance the electronic conductivity of electrodes. Conductive agents may also be used as supports for metal catalysts. Examples of conductive agents include carbon black, activated carbon, graphite, fullerenes, carbon nanotubes, or mixtures thereof. 【0029】 The amount of conductive material in the electrode is, for example, 26.8% by mass or more and 68.6% by mass or less, preferably 36.4% by mass or more and 57.7% by mass or less. 【0030】 Other binders besides the ion exchange resin according to the embodiment may include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorinated rubber, polyacrylic acid compounds, imide compounds, or mixtures thereof. 【0031】 Porous materials consist of metals, carbon isotopes, conductive polymers, or mixtures thereof. Examples of metals include nickel and copper, while examples of carbon isotopes include porous carbon nanotubes, and examples of conductive polymers include polypyrrole and polyaniline. 【0032】 The electrode according to this embodiment can be obtained, for example, by drying or sintering the electrode-forming composition described later. 【0033】 [Membrane electrode assembly] The membrane electrode assembly includes electrodes according to the embodiment. The membrane electrode assembly according to the embodiment can be used for hydrogen production equipment, water electrolysis equipment, fuel cells, etc. Preferably, the membrane electrode assembly includes an anode containing an ion exchange resin according to the embodiment, a cathode, and an ion exchange membrane located between the anode and the cathode. Electrodes according to the embodiment may be used for the anode and cathode. 【0034】 When used in a water electrolysis apparatus, it is preferable to use the electrode according to the embodiment as the anode. The anode is CuCoO x It is preferable to use a catalyst and an ion exchange resin according to the embodiment as a binder. 【0035】 When used in a water electrolysis apparatus, it is preferable to use an electrode different from the electrode in the embodiment for the cathode. For the cathode, a Pt / C catalyst may be used as the catalyst, and an ion exchange resin with an ion exchange capacity greater than 0.80 meq. / g may be used as the binder. 【0036】 The ion exchange membrane may be formed solely from an ion exchange resin, or it may be obtained by supporting an ion exchange resin on a porous substrate. The ion exchange membrane may be a cation exchange membrane or an anion exchange membrane. The ion exchange membrane may be a bipolar membrane containing both a cation exchange membrane and an anion exchange membrane. 【0037】 The ion exchange resin for ion exchange membranes is a resin having ion exchange groups. The ion exchange groups may be cation exchange groups, anion exchange groups, or both. The cation exchange groups include, for example, at least one functional group selected from the group consisting of sulfonic acid groups, carboxylic acid groups, and phosphonic acid groups. The anion exchange groups include, for example, at least one functional group selected from the group consisting of quaternary ammonium groups, pyridinium groups, triazolium groups, imidazolium groups, primary amino groups, secondary amino groups, and tertiary amino groups. Preferably, the ion exchange groups include, for example, at least one functional group selected from the group consisting of quaternary ammonium groups, pyridinium groups, triazolium groups, and imidazolium groups, and more preferably at least one selected from the group consisting of quaternary ammonium groups and pyridinium groups. 【0038】 As the ion exchange resin, at least one of a hydrocarbon resin and a fluororesin may be used. As the hydrocarbon resin, styrene resins, acrylic resins, etc., may be used. As the fluororesin, a resin having a perfluorocarbon skeleton may be used. As the ion exchange resin, it is preferable to use a hydrocarbon resin that does not contain fluorine atoms, and it is more preferable to use a copolymer of a styrene derivative and a divinylbenzene derivative. As the ion exchange resin, the ion exchange resin according to the embodiment may be used. 【0039】 The substrate functions as a support for the ion exchange resin. Examples of substrates include porous films, woven fabrics, nonwoven fabrics, sponges, and films. The substrate is preferably a porous membrane. When a porous membrane is used as the substrate, it is preferable that the pores of the substrate are filled with the ion exchange resin. 【0040】 The base material is, for example, polyolefin resin, fluororesin, polyacrylonitrile, polyvinyl chloride, polyester, polyamide, polysulfone, polyethersulfone, polyphenylene sulfone, polyphenylene sulfide, polyimide, polyethermid, polyamideimide, polycarbonate, polyacrylate, cellulose acetate, polyetheretherketone, or copolymers thereof. Polyolefin resins include polyethylene, polypropylene, polybutadiene, polymethylpentene, polybutene, polypentene, polyhexene, polymethylheptene, and copolymers thereof. Fluorineresins include polytetrafluoroethylene, poly(tetrafluoroethylene-hexafluoropropylene), polyvinylidene fluoride, polyvinylidene fluoride, polyhexafluoropropylene, polychlorotrifluoroethylene, and copolymers thereof. The base material preferably contains polyolefin resin, and more preferably contains polyethylene or polypropylene. 【0041】 The film thickness of the substrate is, for example, 10 μm to 200 μm, preferably 5 μm to 170 μm, more preferably 10 μm to 120 μm, and even more preferably 15 μm to 100 μm. 【0042】 The porosity of the substrate is, for example, 10% to 85%, preferably 20% to 83%, and more preferably 30% to 80%. 【0043】 An ion exchange membrane can be obtained, for example, by applying a polymerizable composition for forming an ion exchange membrane resin to a substrate, curing it to obtain an ion exchange membrane precursor, and then introducing ion exchange groups into this precursor. 【0044】 The membrane electrode assembly is manufactured, for example, by the following method. 【0045】 First, prepare the ion exchange membrane. The ion exchange membrane may be in a wet state, but it is preferable that it be in a dry state. 【0046】 Next, a catalyst is mixed with an ion exchange resin, an ion conductor, a conductive agent, a binder, and a solvent to prepare a first electrode-forming composition. As the solvent, at least one selected from the group consisting of (alcohols with 3 to 7 carbon atoms, such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, etc.) is used. Water may also be used as the solvent. This first electrode-forming composition is applied, for example, to release paper to obtain a first coating film. This first coating film is dried. After drying, the first coating film is peeled off the release paper and laminated onto one main surface of the ion exchange membrane to obtain a first laminate. An ion conductor may be applied to one main surface of the ion exchange membrane. Alternatively, the first laminate may be obtained by directly applying the first electrode-forming composition onto one main surface of the ion-exchange membrane to form a first coating film. Furthermore, the first electrode-forming composition may be directly applied to a conductive porous body, and this conductive porous body may be laminated on the ion-exchange membrane. 【0047】 Next, the ion exchange resin according to the embodiment, the catalyst, and optionally an ion conductive agent, a conductive agent, other binders, and an organic solvent are mixed to prepare a composition for forming the second electrode. As the solvent, at least one selected from the group consisting of (alcohols having 4 to 7 carbon atoms, such as 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, etc.) is used. Water may also be used as the solvent. This composition for forming the second electrode is applied, for example, to release paper to obtain a second coating film. This second coating film is dried. After drying, the second coating film is peeled off the release paper and laminated on the other main surface of the ion exchange membrane of the first laminate to obtain a second laminate. An ion conductive agent may be applied to the other main surface of the ion exchange membrane. Alternatively, the composition for forming the second electrode may be directly applied to the other main surface of the ion exchange membrane to form a second coating film. Alternatively, the composition for forming the second electrode may be directly applied to a conductive porous body, and this conductive porous body may be laminated on an ion exchange membrane. The first coating may also be formed after the second coating. In this way, a second laminate is obtained in which the first coating, the ion exchange membrane, and the second coating are laminated in this order. 【0048】 The second laminate is subjected to heating, pressurization, or both of these processes to integrate the first coating film, the second coating film, and the ion exchange membrane. In this way, a membrane electrode assembly is obtained in which the first electrode, the ion exchange membrane, and the second electrode are laminated in this order. Note that the first or second electrode may be omitted. The first electrode can be used as the cathode, and the second electrode can be used as the anode. 【0049】 [Water electrolysis device] The water electrolysis apparatus according to the embodiment includes a membrane electrode assembly according to the embodiment. Because the water electrolysis apparatus according to the embodiment includes an electrode containing an ion exchange resin according to the embodiment, it has a low cell voltage and excellent electrolysis efficiency. 【0050】 The water electrolysis apparatus including the membrane electrode assembly according to the embodiment will be described in detail below with reference to Figure 1. 【0051】 Figure 1 is a schematic cross-sectional view showing an example of a water electrolysis apparatus according to the embodiment. The water electrolysis apparatus 1 shown in Figure 1 comprises a membrane electrode assembly 4 and a first electrode chamber 2 and a second electrode chamber 3 separated by the membrane electrode assembly 4. 【0052】 The membrane electrode assembly 4 includes an anion exchange membrane 5, a first electrode 6 supported on one main surface of the anion exchange membrane 5, and a second electrode 7 supported on the other main surface of the anion exchange membrane. The first electrode 6 is a cathode, which is a hydrogen generation electrode, and the second electrode is an anode, which is an oxygen generation electrode. The first electrode 6 and the second electrode 7 are connected to a power source via wires (not shown). A gas diffusion layer may be provided on the surfaces of the first and second electrodes. Examples of gas diffusion layers include carbon paper, carbon cloth, nickel foam, titanium foam, and porous graphite. 【0053】 The first electrode chamber 2 is equipped with a first electrode 6 and connected to a hydrogen discharge pipe 8. The hydrogen discharge pipe 8 is connected to a hydrogen tank (not shown). The first electrode chamber 2 may be provided with a first partition wall (not shown). The first partition wall is provided with a plurality of grooves connected to the first electrode chamber 2 and a hydrogen discharge passage connected to these grooves and the hydrogen discharge pipe 8. The first partition wall is preferably made of an electronically conductive material. For example, a metal plate can be used for the first partition wall. The first partition wall may be in contact with the gas diffusion layer described above. 【0054】 The second electrode chamber 3 is equipped with a second electrode 7, and an oxygen discharge pipe 9 and a water supply pipe 10 are connected to it. The oxygen discharge pipe 9 is connected to an oxygen tank (not shown). The water supply pipe 10 is connected to a water supply device (not shown). The second electrode chamber 3 may be provided with a second partition wall (not shown). The second partition wall is provided with a plurality of grooves connected to the second electrode chamber 3, and oxygen discharge passages connected to these grooves, the oxygen discharge pipe 9, and the water supply pipe 10. The second partition wall is preferably made of an electronically conductive material. For example, a metal plate can be used for the second partition wall. The second partition wall may be in contact with the gas diffusion layer described above. 【0055】 Next, a hydrogen production method using a water electrolysis apparatus according to an embodiment will be described in detail with reference to Figure 2. 【0056】 First, the liquid to be treated is supplied to the second electrode chamber 3 via the water supply pipe 10. The liquid to be treated may be water or an alkaline aqueous solution. An alkaline aqueous solution is, for example, an aqueous solution of an alkali metal hydroxide, carbonate, or bicarbonate. The pH of the alkaline aqueous solution is, for example, 10 to 14. The concentration of the alkaline aqueous solution is, for example, 0.1% by mass to 30% by mass. 【0057】 The liquid to be processed that comes into contact with the membrane electrode assembly 4 is held in the anion exchange membrane 5. In other words, the liquid to be processed is supplied to the first electrode chamber 2 via the anion exchange membrane 5. 【0058】 Next, power is supplied to the first electrode 6 and the second electrode 7 from a power source (not shown). As a result, water (H2O) is decomposed in the first electrode 6 as shown in formula (A) below, producing hydrogen (H2) and hydroxide ions (OH). - ) is generated. The generated hydroxide ions are supplied to the second electrode 7 via the anion exchange membrane 5. At the second electrode 7, the supplied hydroxide ions are decomposed and synthesized into oxygen (O2) and water (H2O) as shown in formula (B) below. 【0059】 2H2O + 2e - → H2 + 2OH - (A) 2OH - → 1 / 2O2 + H2O + 2e - (B) The hydrogen gas generated in the first electrode chamber 2 is supplied to the hydrogen tank via the hydrogen discharge pipe 8. The oxygen gas generated in the second electrode chamber 3 is supplied to the oxygen tank via the oxygen discharge pipe 9. [Examples] 【0060】 (Example 1) Binder synthesis Manufacturing process 1 (Manufacturing of chloromethyl group-containing resin) 20.0 g of commercially available styrene-ethylene-butylene-styrene (SEBS) copolymer (weight-average molecular weight 140,000, styrene content 12% by weight) (containing 23 mmol of benzene rings) was dissolved in a mixed solvent of 256 mL of chloroform and 233 mL (3.1 mol) of chloromethyl methyl ether. Then, 38.90 g of a 0.25 mol / L tin(IV) chloride chloroform solution was added, and the mixture was reacted at 35-37°C for 2 hours to introduce chloromethyl groups into the resin. Subsequently, 78 ml of a 1:1 mixed solution of 1,4-dioxane and water was added to the reaction solution to stop the reaction. After that, the resin was added to 1200 ml of aqueous methanol to precipitate it, washed several times with 800 mL of a 1:1 mixed solution of deionized water and methanol, and then stored in 800 mL of methanol. 19.3 g of styrene-ethylene-butylene-styrene (SEBS) copolymer with chloromethyl groups introduced into the benzene rings was obtained as a chloromethyl group-containing resin. 【0061】 Manufacturing process 2 (Quaternary grading of chloromethyl group-containing resin) In a polypropylene container, 12.9 g of styrene-ethylene-butylene-styrene (SEBS) copolymer with chloromethyl groups introduced in manufacturing step 1, 412 mL of deionized water, 96 mL of acetone, and 145 mL of 30 percent trimethylamine were added, and the container was sealed tightly with a lid and sealing tape. The mixture was then stirred for 20 hours using a mixing rotor. After stirring, 0.5 L of 1.5 mol / L hydrochloric acid was added and stirred for 15 minutes, followed by filtration. Then, 1.5 L of 0.5 mol / L hydrochloric acid was added to the remaining residue and stirred for 15 minutes, followed by filtration. The above procedure was repeated twice. The residue was then collected and added to 1.0 L of deionized water and stirred for 15 minutes, filtered to remove the residue, and the pH of the filtrate was measured. This was repeated until the filtrate reached a pH of 7. Subsequently, the residue was added to 1.0 L of 1.0 mol / L potassium bicarbonate aqueous solution, stirred for 30 minutes, and filtered. A portion of the filtrate was collected, and after adjusting the pH to below 3 with nitric acid aqueous solution, 0.01 mol / L silver nitrate aqueous solution was added to check for turbidity. The stirring and filtering process using potassium bicarbonate aqueous solution was repeated until turbidity disappeared when silver nitrate aqueous solution was added. After that, the residue was collected and added to 0.8 L of deionized water, stirred for 15 minutes, filtered to remove the residue, and the pH of the filtrate was measured. This was repeated until the filtrate reached a pH of 7. Finally, the residue was added to 0.4 L of tetrahydrofuran, stirred for 15 minutes, filtered, and then the residue was collected. This process was repeated three times. After that, the residue was added to 0.4 L of stabilizer-free tetrahydrofuran, stirred for 15 minutes, and then stored in the stabilizer-free tetrahydrofuran. A bicarbonate-type ion exchange resin was obtained by the above method. 【0062】 (Example 2) Manufacturing process 1 (Production of chloromethyl group-containing resin) 20.0 g of commercially available polystyrene-poly(ethylene-butylene)-polystyrene triblock copolymer (weight-average molecular weight 140,000, styrene content 12% by weight) (containing 23 mmol of benzene rings) was dissolved in a mixed solvent of 256 mL of chloroform and 233 mL (3.1 mol) of chloromethyl methyl ether. Then, 40.55 g of a 0.51 mol / L tin(IV) chloride chloroform solution was added, and the mixture was reacted at 35-37°C for 2 hours to introduce chloromethyl groups into the resin. Subsequently, 20.5 g of styrene-ethylene-butylene-styrene (SEBS) copolymer with chloromethyl groups introduced into the benzene rings was obtained using the same volume of deionized water, aqueous solution, and solvent as in Example 1. 【0063】 Manufacturing process 2 (Quaternary grading of chloromethyl group-containing resin) In a polypropylene container, 20.5 g of styrene-ethylene-butylene-styrene (SEBS) copolymer with chloromethyl groups introduced in manufacturing step 1, 656 mL of deionized water, 119 mL of acetone, and 230 mL of 30 percent trimethylamine were added, and the container was sealed tightly with a lid and sealing tape. The mixture was then stirred for 18 hours using a mixing rotor. After stirring, a bicarbonate-type ion exchange resin was obtained in the same manner as in Example 1, except that the volumes of deionized water, aqueous solution, and solvent (except hydrochloric acid) used were all doubled compared to Example 1. 【0064】 (Comparative Example 1) Manufacturing process 1 (Manufacturing of chloromethyl group-containing resin) 20.0 g of commercially available polystyrene-poly(ethylene-butylene)-polystyrene triblock copolymer (weight-average molecular weight 140,000, styrene content 12% by weight) (containing 23 mmol of benzene rings) was dissolved in a mixed solvent of 256 mL of chloroform and 233 mL (3.15 mol) of chloromethyl methyl ether. Then, 32.69 g of a 0.96 mol / L tin(IV) chloride chloroform solution was added, and the mixture was reacted at 35-37°C for 2 hours to introduce chloromethyl groups into the resin. Subsequently, 18.0 g of styrene-ethylene-butylene-styrene (SEBS) copolymer with chloromethyl groups introduced into the benzene rings was obtained in the same manner as in Example 1. 【0065】 Manufacturing process 2 (Quaternary grading of chloromethyl group-containing resin) A polypropylene container was filled with 18.0 g of styrene-ethylene-butylene-styrene (SEBS) copolymer into which chloromethyl groups were introduced in manufacturing step 2, 577 mL of deionized water, 215 mL of acetone, and 203 mL of 30 percent trimethylamine. The container was then sealed tightly with a lid and sealing tape. The mixture was then stirred for 18 hours using a mixing rotor. After stirring, a bicarbonate-type ion exchange resin was obtained in the same manner as in Example 2. 【0066】 (Comparative Example 2) We used Polyflon PTFED-210C, a fluoropolymer suspension manufactured by Daikin Industries, Ltd. The PTFE-D210C used was pre-diluted to a 10% by weight concentration using deionized water. 【0067】 <Evaluation Method> 1) Solution of anion exchange resin The anion exchange resins prepared in Examples 1-2 and Comparative Example 1 were dissolved in 1-hexanol to make a 5 wt% solution. Then, 1-hexanol was added to the solution until the concentration was 3.5 wt%, and the same amount of 1-hexanol that had been added was removed by distillation. This addition and removal of 1-hexanol was repeated three times to remove the remaining tetrahydrofuran, and finally, 1-hexanol was added to the solution until the concentration was 5 wt%. 【0068】 The solution prepared by the above method, in which the anion exchange resin is dissolved in alcohol, will be referred to here as the binder. 【0069】 2) Anion exchange capacity and water content 1) The binder prepared in step 1) was cast onto a Teflon® petri dish and then thoroughly dried to create an anion exchange membrane made of anion exchange resin. This membrane was then used in a 150 mL 0.5 mol·L solution. -1- It was immersed in an NaCl aqueous solution for 30 minutes and then taken out. This immersion in the NaCl aqueous solution was repeated 3 times. As a result, a membrane in which the anions of the ion exchange groups were replaced with chloride ions was obtained. This membrane was immersed in 100 mL of 0.2 mol·L -1 - NaNO3 aqueous solution for 15 minutes and then taken out. This immersion in the NaNO3 aqueous solution was repeated 3 times. All the silver nitrate aqueous solutions used in these operations were recovered, and the number of moles of chloride ions (Amol) was quantified using a potentiometric titration apparatus (KEM MUC-610 manufactured by Kyoto Electronics Industry Co., Ltd.) with the silver nitrate aqueous solution. Next, the anion exchange membrane was taken out, the moisture on the surface was wiped off with filter paper, and the weight was measured (D1g). Then, it was dried under reduced pressure at 50 °C for 15 hours or more and its weight was measured (D2g). Based on the above measurement values, the ion exchange capacity and water content were determined by the following equations. 【0070】 Anion exchange capacity = A × 1000 / D2 [meq. / g -1 Water content = D1 × 100 / D2 [%] <Electrolysis evaluation> Preparation of the anode electrode 1.08 g of CuCоОx catalyst, 10.8 g of pure water, and 0.54 g of the binder prepared in each example and comparative example were kneaded to prepare a catalyst ink. In addition, only in Comparative Example 2, 0.168 g of Triton X-100 was further mixed. The catalyst ink was applied to the nickel porous body using an ultrasonic coater until a predetermined catalyst loading amount was reached. The nickel porous body coated with the catalyst ink was dried under reduced pressure at 100 °C for 1 hour using a vacuum oven. Comparative Example 2 was further sintered under reduced pressure at 400 °C for 1 hour after drying. 【0071】 In order to improve the smoothness of the surface of the porous body coated with the above catalyst ink, roll pressing was performed to obtain an electrode. The final catalyst loading was 10 - 12 mg / cm 2 was. 【0072】 <Evaluation results> ​As shown in Table 1 below, the water content of the resins obtained in Examples 1 and 2 and Comparative Example 1 was 27%, 58%, and 98%, respectively. Resins with high water content exhibit large dimensional changes during swelling and low mechanical strength. Electrodes made using resins with low mechanical strength experienced catalyst layer detachment during water electrolysis. Therefore, the binder from Comparative Example 1, which had a water content of 98%, could not be used as an anode. 【0073】 [Table 1] 【0074】 In electrode fabrication, when using PTFE-D-210C from Comparative Example 2, it is absolutely necessary to perform vacuum sintering at 400°C for 1 hour. Without vacuum sintering at 400°C, the mixture of catalyst from Comparative Example 2 and PTFE-D-210C applied to the electrode will not fuse and fix to the nickel porous material, making it unusable as an electrode. In contrast, it was confirmed that electrodes can be fabricated without performing sintering at 380°C for 1 hour.

Claims

[Claim 1] An ion exchange resin having an ion exchange capacity of 0.30 meq. / g or more and 0.80 meq. / g or less, and having a block copolymer structure of styrene-ethylene-butylene-styrene (SEBS). [Claim 2] The ion exchange resin according to claim 1, wherein the ion exchange capacity is 0.40 meq. / g or more and 0.65 meq. / g or less. [Claim 3] The ion exchange resin according to claim 1, wherein the water content is 10% or more and 60% or less. [Claim 4] A composition for forming electrodes, comprising the ion exchange resin, catalyst, and solvent described in claim 1. [Claim 5] An electrode comprising the ion exchange resin described in claim 1. [Claim 6] An anode for a water electrolysis apparatus, comprising the ion exchange resin described in claim 1. [Claim 7] A membrane electrode assembly comprising an anode containing the ion exchange resin described in claim 1, a cathode, and an ion exchange membrane located between the anode and the cathode. [Claim 8] The membrane electrode assembly according to claim 7, wherein the ion exchange membrane comprises a hydrocarbon-based ion exchange resin that does not contain fluorine atoms. [Claim 9] A water electrolysis apparatus comprising the membrane electrode assembly described in claim 7.

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