Resin composition, method for producing resin composition, and electrochemical device

Abstract

The present invention addresses the problem of providing a resin composition having excellent alkaline resistance and a method for producing said resin composition. The present invention also addresses the problem of providing, by using said resin composition, an electrochemical device that enables improvement in output and durability.　In order to solve the problems, provided are: a resin composition including a structural unit represented by formula (1); a method for producing same; and an electrochemical device using said resin composition. (In the formula, E is a spacer portion and represents a benzene ring, a benzene derivative in which at least one atom is substituted with a hydrocarbon group having 1-6 carbon atoms, or a carbon chain having at least 2 carbon atoms and optionally including a heteroatom, Im represents an imidazole ring including an ion conductive group, R1-R5 each independently represent a carbon chain having 1-10 carbon atoms and including hydrogen, a halogen, or a heteroatom, and X- represents an anion.)

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a method for producing the resin composition, and also to an electrochemical device using the resin composition as a material for an electrolyte layer and / or an electrode. [Background technology]

[0002] In general, it is common to design the structural units of a resin composition and impart desired functions to the resin composition, and it is also common to use functional resin compositions as materials for various devices.

[0003] An example of a device using a functional resin composition is an electrochemical device that converts electrical energy and chemical energy. A specific example of the use of a functional resin composition is as a material for an electrolyte layer (electrolyte membrane) or an electrode in an electrochemical device.

[0004] Fuel cells and metal-air batteries are known as such electrochemical devices. Fuel cells and metal-air batteries use air (oxygen) as the active material on the positive electrode side, and convert the energy generated by a chemical reaction with the active material (fuel, metal, etc.) on the negative electrode side into electrical energy, which gives them the advantage of high energy conversion efficiency. Among these, solid polymer fuel cells in particular have a low operating temperature and low electrolyte resistance, and because they use highly active catalysts, they can produce high output even in a small size, and are expected to be put into practical use soon.

[0005] For example, proton-conducting fuel cells, which use hydrogen as fuel, have high power generation efficiency and are a promising solution to the depletion of fossil fuels. In addition, they can significantly reduce carbon dioxide emissions, making them a means of curbing global warming. Therefore, there is a desire to develop them as a power source for home cogeneration and automobiles.

[0006] In recent years, attention has been drawn to non-platinum anion-conducting fuel cells, which can use fuels other than hydrogen, such as methanol and hydrazine hydrate, and have been reported to exhibit output three times higher than that of proton-conducting fuel cells. Because of their ease of installation as a liquid fuel, safety, and high output density, anion-conducting fuel cells are being considered for use in fuel cell vehicles, particularly those designed for compact cars, and as disaster-response power sources for wireless base stations and other applications. Furthermore, anion-conducting fuel cells do not require the strongly acidic conditions required for operation, and their greatest advantage is that they can use inexpensive materials such as iron and cobalt, which dissolve under strongly acidic conditions and are therefore not suitable for proton-conducting fuel cells, rather than precious metals like platinum, for the electrodes. Therefore, low-cost, high-output fuel cells are expected.

[0007] In such anion conduction fuel cells, the electrolyte membrane for anion conduction fuel cells (hereinafter referred to as "anion conduction electrolyte membrane") functions as both an "electrolyte" for conducting hydroxide ions (anions) and a "separator" for preventing direct mixing of the fuels methanol and hydrazine with oxygen. Therefore, anion conduction electrolyte membranes are required to have high ionic conductivity, chemical stability and heat resistance sufficient to withstand long-term use in alkaline aqueous solutions at high temperatures (>60°C), which are the operating conditions of the cell, and a consistent water retention capacity to maintain high ionic conductivity. On the other hand, because of their role as a separator, the membrane is also required to have excellent mechanical strength and dimensional stability, as well as high barrier properties against methanol, hydrazine, and oxygen. However, practically usable anion exchange electrolyte membranes have hardly been developed yet. Compared with Nafion (registered trademark) and other proton exchange electrolyte membranes that have a proven track record, current anion exchange electrolyte membranes have poor performance in terms of electrical conductivity, mechanical strength, fuel permeability, etc., and also have extremely low alkali resistance, which is their greatest durability issue.

[0008] Therefore, active efforts have been made to develop anion exchange membranes that solve the above-mentioned problems. For example, anion exchange membranes have been developed in which a hydrocarbon film such as porous polyethylene is used as a substrate and the pores of the film are filled with a crosslinked anion exchange resin (Patent Documents 1 to 3). Also proposed is a method for producing anion exchange membranes in which an alkylammonium salt is introduced by a quaternization reaction into a substrate membrane made of a polymerized mixture of haloalkylstyrene, elastomer, and epoxy compound (Patent Document 4), and a method for producing anion exchange membranes in which an anion exchange group precursor monomer is subjected to radiation-induced graft polymerization onto a substrate made of a fluorine-based polymer and then an alkylammonium salt is introduced (Patent Document 5). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-367626 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-203455 [Patent Document 3] Special Publication No. 2019-518809 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-202074 [Patent Document 5] Japanese Patent Application Laid-Open No. 2000-331693 Summary of the Invention [Problem to be solved by the invention]

[0010] As described in Patent Documents 1 to 5, in existing anion membranes, the anion exchange groups are mainly alkylammonium salts obtained by quaternization of alkylamines such as trimethylamine, and therefore the water content is very high and the membrane is not strong enough to withstand use. Furthermore, alkali-resistant anion exchange membranes have been reported in which the anion exchange groups are imidazolium salts that suppress nucleophilic substitution reactions, but these membranes suffer from elimination reactions due to other decomposition reactions, and the membranes lack sufficient alkali resistance.

[0011] Therefore, an object of the present invention is to provide a resin composition having excellent alkali resistance and a method for producing this resin composition. Another object of the present invention is to provide an electrochemical device that uses the above resin composition and that enables improved output and durability. [Means for solving the problem]

[0012] As a result of intensive research into the above-mentioned problems, the present inventors have come to the finding that it is possible to impart alkali resistance and functionality relating to improved ion conductivity to a resin composition by ensuring a certain distance between the main chain and the ion-conducting group in the resin composition and chemically protecting, with a bulky substituent, the sites that serve as the starting points for nucleophilic substitution reactions and elimination reactions, which are the main causes of alkali-induced decomposition. This finding led to the completion of the present invention. That is, the present invention provides the following resin composition, method for producing a resin composition, and electrochemical device.

[0013] The resin composition of the present invention, which is intended to solve the above problems, is characterized by containing a structural unit represented by the following formula (1). [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R 1 ~R 5 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.) According to this feature, by providing a spacer portion (E) between the main chain and the ion-conducting group (Im) as shown in formula (1), it is possible to improve the ion conductivity and alkali resistance of the resin composition. In addition, by protecting each position on the imidazole ring of the ion-conducting group (Im), it is possible to suppress elimination reactions initiated by the β-hydrogen, hydrolysis reactions due to nucleophilic attack at the 2-position, and oxidative decomposition reactions at the 4- and 5-positions. This, combined with the effect of providing the spacer portion (E), makes it possible to further improve the alkali resistance of the resin composition.

[0014] In addition, one embodiment of the resin composition of the present invention is characterized by further containing a structural unit represented by the following formula (2). [ka] (In the formula, R 6 is a carbon chain having 1 to 10 carbon atoms, which contains hydrogen, halogen or heteroatoms, and I is an integer of 0 to 5. According to this feature, by combining the structure of formula (1) and formula (2), the repulsion between the positive charges of the ion-conducting group (Im) in formula (1) is reduced, and the steric protection effect of the benzene ring makes it possible to further suppress the nucleophilic substitution reaction of the carbon at the bonding position between the spacer part (E) and the ion-conducting group (Im) and the decomposition reaction of the imidazole ring in the ion-conducting group (Im), thereby making it possible to further improve the alkali resistance of the resin composition.

[0015] In one embodiment of the resin composition of the present invention, among the structural units represented by the formula (1), in the structural unit represented by the following formula (3), R 1 and R 3 At least one of the following has two or more carbon atoms: [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; R 1 , R 3 , R 4 , R 5 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.) According to this feature, the protecting group (R 1 and R 3 By making at least one of the groups (Im) bulky as a carbon chain having two or more carbon atoms, it is possible to increase hydrophobicity, reduce repulsion between the positive charges of the ion-conducting groups (Im), and suppress elimination and decomposition reactions of the ion-conducting groups (Im). This makes it possible to further improve the ion conductivity and alkali resistance of the resin composition.

[0016] Furthermore, one embodiment of the resin composition of the present invention is characterized in that it has a conductivity of 40 mS / cm or more and maintains a conductivity of 70% or more after immersion in a 1 M aqueous potassium hydroxide solution heated to 80°C for 200 hours. According to this feature, the electrical conductivity and electrical conductivity retention rate of the resin composition satisfy specific values, and thus the resin composition can be used as a highly practical resin composition that is endowed with functions related to ion conductivity and alkali resistance. In particular, when the resin composition is used as a material for electrochemical devices such as fuel cells and metal-air batteries, it can be used as a material with sufficient practicality.

[0017] The method for producing a resin composition of the present invention, which solves the above-mentioned problems, is a method for producing a resin composition containing a structural unit represented by the following formula (1), and is characterized by including a step of introducing a spacer moiety (E) and / or an ion-conducting group (Im) in the following formula (1) by radiation-induced graft polymerization. [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R 1 ~R 5 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.) This feature allows for a high degree of freedom in the design of polymer chains, and by using radiation-induced graft polymerization that can introduce various ion-conducting groups through covalent bonds, it becomes possible to easily produce resin compositions having structural units as designed.

[0018] The electrochemical device of the present invention, which solves the above-mentioned problems, is an electrochemical device comprising an electrolyte layer and two electrodes arranged opposite each other with the electrolyte layer sandwiched therebetween, and is characterized in that the electrolyte layer and / or the electrodes contain the above-mentioned resin composition. According to this feature, by using a resin composition having high ionic conductivity and alkali resistance as a material for an electrolyte layer and / or an electrode in an electrochemical device, it is possible to improve the output and durability of the electrochemical device.

[0019] Furthermore, one embodiment of the electrochemical device of the present invention is characterized in that it is a fuel cell or a metal-air battery. According to this feature, it is possible to fully utilize the functions of the resin composition relating to high ionic conductivity and alkali resistance, overcome the problems of low output and durability that have been encountered in conventional fuel cells or metal-air batteries, and provide a highly practical fuel cell or metal-air battery. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a resin composition having excellent alkali resistance and a method for producing the resin composition. Furthermore, according to the present invention, it is possible to provide an electrochemical device that uses the above resin composition and that enables improved output and durability. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic explanatory diagram showing the structure of an electrochemical device according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing the results of an output test on electrochemical devices in examples of the present invention and comparative examples. [Figure 3] FIG. 10 is a diagram showing the results of a durability test on electrochemical devices in examples of the present invention and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the resin composition, the method for producing the resin composition, and the electrochemical device of the present invention will be described in detail. The resin composition, the method for producing the resin composition, and the electrochemical device described in the embodiments are merely examples for explaining the present invention, and the present invention is not limited thereto.

[0023] [Resin composition] (Structure of Resin Composition) The resin composition according to an embodiment of the present invention contains a structural unit represented by the following formula (1).

[0024] [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R 1 ~R 5 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.)

[0025] The spacer portion (E) in formula (1) ensures a distance between the main chain and the ion-conducting group (Im), thereby improving the ion conductivity of the resin composition and also improving the alkali resistance of the resin composition.

[0026] The spacer portion (E) is selected from a benzene ring, a benzene derivative substituted with at least one hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom. The heteroatom is preferably selected from nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S). Here, the distance between the main chain and the ion-conducting group (Im) is preferably within a range where the ion-conducting group (Im) is under the influence of the hydrophobicity of the main chain while maintaining a certain distance between the main chain and the ion-conducting group (Im). This makes it possible to suppress hydrolysis caused by nucleophilic attack on the ion-conducting group (Im), thereby maintaining high ion conductivity as a resin composition and further improving alkali resistance. Therefore, the spacer portion (E) is preferably selected from a benzene ring, a benzene derivative in which at least one hydrogen atom on the benzene ring is substituted with a hydrocarbon group having 1 to 3 carbon atoms, or a carbon chain having 2 to 5 carbon atoms which may contain a heteroatom. Furthermore, in consideration of the yield in the production of the resin composition, the ease of setting reaction conditions, the ease of obtaining reaction raw materials, etc., the spacer portion (E) is more preferably selected from a benzene derivative in which at least one hydrogen atom on the benzene ring or the benzene ring is substituted with a hydrocarbon group having 1 to 3 carbon atoms.

[0027] The ion-conducting group (Im) in formula (1) is a group having a protecting group (R 1 ~R 5 ) Conventionally, anion exchange electrolyte membranes containing alkylammonium hydroxide salts as ion-conducting groups have had problems such as being very unstable due to their strong basicity and not having sufficient strength due to their high water content. On the other hand, the ion-conducting group (Im) in the embodiment of the present invention has an imidazole ring, which disperses the positive charge due to the conjugated structure and reduces the basicity, as shown in formula (1). This allows the resin composition to have low water content, and when used as an anion exchange electrolyte membrane, it is possible to obtain sufficient strength (stabilization). In addition, in the ion-conducting group (Im), a protecting group (R 1 ~R 5 By providing the spacer portion (E), it is possible to suppress elimination reactions originating from the β-hydrogen, hydrolysis reactions due to nucleophilic attack on the 2-position, and oxidative decomposition reactions at the 4- and 5-positions. This, combined with the effect of providing the spacer portion (E), makes it possible to further improve the alkali resistance of the resin composition.

[0028] R in Equation (1) 1 ~R 5 are each an independent carbon chain having 1 to 10 carbon atoms, and are not particularly limited as long as this carbon chain contains hydrogen, halogen or a heteroatom. The heteroatom is preferably selected from nitrogen (N), oxygen (O), phosphorus (P) and sulfur (S).

[0029] R 1 ~R 5 In the above, "containing halogen" means that a halogeno group such as a fluoro group, a chloro group, a bromo group, or an iodo group may be contained. Also, R 1 ~R 5 In the above, "containing a heteroatom" means, for example, an amino group (-NR2), an ammonium group (-NR3 +), a cyano group (-CN) or other nitrogen-containing functional group, a hydroxyl group (-OH) an alkoxy group (-OR) or other oxygen-containing functional group, a sulfur-containing functional group such as a thiol (-SH), and a functional group containing multiple heteroatoms such as a nitro group (-NO2), an isocyanate group (-NCO), a phosphonic acid (-P(=O)(OH)2), a phosphoric acid (-H2PO4), or a thioester (-C(=O)S). In addition, this means that the carbon skeleton or the terminal thereof may contain a linking group consisting of a heteroatom, such as an imino group (-NR-), an ether group (-O-), an amide group (-C(=O)-NR-), a phosphoric acid amide group (-P(=O)-NR-), a phosphine oxide group (-P(=O)R-), a phosphoric acid ester group (-PO4H-), a sulfide group (-S-), a disulfide group (-SS-), or a sulfone group (-SO2-). Therefore, R 1 ~R 5 Examples of such hydrocarbon groups include a hydrocarbon group having two carbon atoms and containing an amino group, such as -CH2-CH2-NH2, a hydrocarbon group having two carbon atoms and containing an imino group inside the carbon skeleton, such as -CH2-NH-CH3, and a hydrocarbon group having two carbon atoms and containing an imino group at the end of the carbon skeleton, such as -NH-CH2-CH3.

[0030] R 1 ~R 5 The number of carbon atoms in R is usually 1 or more and 10 or less, preferably 6 or less, and more preferably 3 or less. 1 ~R 5 is not limited to a linear saturated hydrocarbon group, but may have a branched structure and / or a cyclic structure, and may further have an unsaturated bond.

[0031] R 1 ~R 5Examples of the carbon chain (hydrocarbon group) having 1 to 10 carbon atoms include linear hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; branched hydrocarbon groups having 1 to 10 carbon atoms, such as i-propyl, i-butyl, s-butyl, t-butyl, i-pentyl, s-pentyl, t-pentyl, neopentyl, i-hexyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 1-ethylbutyl, 2-ethylbutyl, 1,2-dimethylbutyl, and 2,3-dimethylbutyl groups; and cyclic hydrocarbon groups having 3 to 10 carbon atoms, such as cyclohexyl, cyclopentylmethyl, and cyclohexylmethyl groups. Also, preferred are hydrocarbon groups having 3 to 8 carbon atoms, more preferred are methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl groups, and even more preferred are methyl, ethyl, and n-propyl groups.

[0032] X in formula (1) - is an anion that serves as a counter ion of the ion-conducting group (Im), and the specific type of the anion is not particularly limited as long as it can form an imidazolium salt. - Examples of the ion include hydroxide ion, carbonate ion, nitrate ion, sulfate ion, phosphate ion, and halogen ions such as chloride ion, bromide ion, and iodide ion, with hydroxide ion being particularly preferred.

[0033] In the resin composition of this embodiment, an example of the structure based on formula (1) is one shown in formula (4). [ka] (In the formula, R 7 represents a single bond or a hydrocarbon group having 1 to 6 carbon atoms, Im represents an ion-conducting group containing an imidazole ring, and R 1 ~R 5are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.) The resin composition of this embodiment has the structural unit of formula (4), which allows the rigid benzene ring skeleton to easily and reliably ensure a suitable distance between the main chain and the ion-conducting group (Im). In addition, the n-electrons of the benzene ring in formula (4) disperse the positive charge, which has the advantage of stabilizing the resin composition.

[0034] The resin composition according to an embodiment of the present invention may have any structure other than that represented by the above-described formula (1), and is not particularly limited thereto. However, it is preferable that the resin composition further has a structural unit represented by the following formula (2) in addition to the structural unit represented by the formula (1). [ka] (In the formula, R 6 is a carbon chain having 1 to 10 carbon atoms, which contains hydrogen, halogen or heteroatoms, and I is an integer of 0 to 5.

[0035] R in Equation (2) 6 As mentioned above, 1 ~R 5 Similarly, it is a carbon chain having 1 to 10 carbon atoms, and is not particularly limited as long as this carbon chain contains hydrogen, halogen or a heteroatom. The heteroatom is preferably selected from nitrogen (N), oxygen (O), phosphorus (P) and sulfur (S).

[0036] R 6 The number of carbon atoms in the above R 1 ~R 5 Similarly, it is usually 1 or more and 10 or less, preferably 6 or less, and more preferably 3 or less. 6 is not limited to a linear saturated hydrocarbon group, but may have a branched structure and / or a cyclic structure, and may further have an unsaturated bond.

[0037] R 6 As the alkyl group, those having a halogeno group in a carbon chain of 1 to 3 carbon atoms are preferred, and examples thereof include a chloromethyl group, a bromomethyl group, a chloroethyl group, a bromoethyl group, a chloropropyl group, and a bromopropyl group.

[0038] By combining the formulas (1) and (2) in the resin composition of the present invention, the repulsion between the positive charges of the ion-conducting group (Im) in formula (1) is reduced, and the steric protection effect of the benzene ring further suppresses the nucleophilic substitution reaction of the carbon at the bonding position between the spacer portion (E) and the ion-conducting group (Im) and the decomposition reaction of the imidazole ring in the ion-conducting group (Im), thereby further improving the alkali resistance of the resin composition.

[0039] A specific structure of the resin composition of this embodiment, which combines formula (1) and formula (2), is as shown in formula (5). [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R 1 ~R 6 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion, and n and m indicate molar ratios.

[0040] Here, if the molar ratio (value of m) of the structural unit based on formula (2) in formula (5) is too small, the steric protection effect of the benzene ring cannot be sufficiently obtained. On the other hand, if the molar ratio (value of m) of the structural unit based on formula (2) in formula (5) is too large, it is undesirable to make the resin composition more hydrophobic than necessary. Therefore, the molar ratio (n:m) in formula (5) is preferably n:m=8:2 to 2:8, more preferably n:m=7:3 to 4:6.

[0041] In addition, another example of the resin composition according to the embodiment of the present invention is a resin composition having a structural unit represented by the following formula (3) among the structural units represented by the above formula (1), and R 1 and R 3 At least one of the groups preferably has two or more carbon atoms. [ka] (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; R 1 , R 3 , R 4 , R 5 are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains hydrogen, halogen or heteroatom, and X - indicates an anion.)

[0042] The spacer portion (E) and the protecting group (R 1 , R 3 , R 4 , R 5 ) are the same as the spacer portion and protecting group in the above formula (1). 1 , R 3 At least one of the groups has 2 or more carbon atoms. At this time, taking into consideration the stability (low water content) of the resin composition and the yield of production, R 1 and R 3 The number of carbon atoms in R is preferably 6 or less, and 1and R 3 It is preferable that the carbon numbers of the groups are different.

[0043] The protecting group (R 1 , R 3 , R 4 , R 5 ), the protecting group (R 1 and R 3 By making at least one of the groups (Im) bulky as a carbon chain having two or more carbon atoms, it is possible to increase hydrophobicity, reduce repulsion between the positive charges of the ion-conducting groups (Im), and suppress elimination and decomposition reactions of the ion-conducting groups (Im). This makes it possible to further improve the ion conductivity and alkali resistance of the resin composition. In a resin composition having a structural unit of formula (3), the ion-conducting group (Im) itself has a bulky protecting group, so that the decomposition reaction of the ion-conducting group (Im) can be suppressed without the steric protection effect of the structural unit of formula (2). Therefore, in a resin composition having a structural unit of formula (3), it is not necessary to intentionally include the structural unit of formula (2), but this does not exclude the combination of the structural unit of formula (3) and the structural unit of formula (2).

[0044] (Method of producing resin composition) The resin composition according to an embodiment of the present invention can be produced by a method including a step of introducing the spacer moiety (E) and / or the ion-conducting group (Im) in formula (1) by radiation-induced graft polymerization. Radiation-induced graft polymerization is known to offer a high degree of freedom in polymer chain design and to enable the introduction of various ion-conducting groups via covalent bonds. Therefore, by using radiation-induced graft polymerization in the production of a resin composition according to an embodiment of the present invention, it becomes possible to easily produce a resin composition having structural units as shown in formula (1) or (2).

[0045] One example of a method for producing a resin composition according to an embodiment of the present invention involves introducing a compound having a structure that will become the spacer moiety (E) in formula (1) into a polymer substrate by radiation-induced graft polymerization, and then replacing some of the introduced functional groups with a compound having a structure that will become the ion-conducting group (Im) in formula (1). This production method will be specifically exemplified in Example 1-1 below.

[0046] Another example of the production of a resin composition according to an embodiment of the present invention is to introduce a compound having a structure that serves as the spacer moiety (E) and the ion-conducting group (Im) in formula (1) into a polymer substrate by radiation-induced graft polymerization. This production method will be specifically exemplified in Example 1-2 described later.

[0047] In the following description of the production of the resin composition, the compound (monomer) containing the structure of the spacer moiety (E) and / or the ion-conducting group (Im) in formula (1) that is introduced into the polymer substrate by radiation-induced graft polymerization will be referred to as the "starting material."

[0048] Here, the polymer substrate may be made of a fluorine-based polymer, an olefin-based polymer, or the like. and those made of aromatic polymers.

[0049] Examples of fluorine-based polymers include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinyl fluoride (PVF), polychlorotrifluoroethylene copolymer (ECTFE), etc. When using a polymer substrate made of a fluorine-based polymer, crosslinking the fluorine-based polymer in advance can improve the heat resistance and swelling suppression ability of the resin composition, and can particularly improve the performance as an anion exchange electrolyte membrane.

[0050] Examples of olefin polymers include low-density, high-density, and ultra-high-molecular-weight polyethylene and polypropylene. Polymers containing trimethylpentene as a polymerization unit can also be mentioned. When using a polymer substrate made of an olefin polymer, crosslinking the olefin polymer in advance can further improve the heat resistance and swelling suppression ability of the resin composition.

[0051] Examples of aromatic polymers include polyimide, polyamideimide, polyetherimide, polyethylene naphthalate, liquid crystalline aromatic polymers, polyether ether ketone, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, etc., which are known as high-performance resins (super engineering plastics). When a polymer substrate made of an aromatic polymer is used, the heat resistance and swelling suppression ability of the resin composition can be further improved by crosslinking the aromatic polymer in advance.

[0052] As the resin composition in the embodiment of the present invention, a composite material of a thermoplastic resin and various inorganic fillers, or a polymer alloy can also be used as the polymer substrate, particularly for the purpose of improving the durability and suppressing swelling of the anion exchange electrolyte membrane.

[0053] The specific method, conditions, etc. of the radiation-induced graft polymerization are not particularly limited, and known methods can be appropriately adopted. For example, specific methods include a simultaneous irradiation method in which the polymer substrate and the starting material are simultaneously irradiated with radiation to cause graft polymerization, and a pre-irradiation method in which the polymer substrate is first irradiated with radiation and then brought into contact with the starting material to cause graft polymerization. The pre-irradiation method is preferred because it produces a smaller amount of homopolymer. As for the pre-irradiation method, known methods can be used, such as a polymer radical method in which a polymer substrate is irradiated with radiation in an inert gas, or a peroxide method in which a polymer substrate is irradiated with radiation in the presence of oxygen.

[0054] The radiation in radiation-induced graft polymerization refers to ionizing radiation such as electron beams, gamma rays, and ion beams. The energy amount of the radiation is usually 1 kGy or more, preferably 5 kGy or more, and more preferably 10 kGy or more, and usually 500 kGy or less, preferably 100 kGy or less, and more preferably 50 kGy or less. The temperature conditions for irradiation with radiation are usually room temperature, and usually 150°C or lower, preferably 50°C or lower, and more preferably 30°C or lower. Within the above range, sufficient ionic conductivity can be ensured and deterioration of the polymer-based material can be suppressed.

[0055] When the radiation-induced graft polymerization step of the present invention is a pre-irradiation method, the method for contacting the polymer substrate with the starting material is not particularly limited, but an example is a method in which the polymer substrate after irradiation is immersed in a solution containing the starting material. Examples of solvents used for the solution containing the starting materials include dichloroethane, chloroform, N-methylformaldehyde, N-methylacetamide, N-methylpyrrolidone, γ-butyrolactone, n-hexane, dioxane, methanol, ethanol, 1-propanol, tert-butanol, toluene, xylene, cyclohexane, cyclohexanone, and dimethyl sulfoxide. The concentration of the starting material in the solution is not particularly limited and can be appropriately set depending on the purpose. For example, the concentration of the starting material is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 100% by weight or less, preferably 80% by weight or less, more preferably 60% by weight or less.

[0056] The immersion temperature is usually room temperature or higher, preferably 40°C or higher, more preferably 50°C or higher, and usually 120°C or lower, preferably 100°C or lower, more preferably 80°C or lower. The immersion time is usually 0.5 hours or more, preferably 1 hour or more, more preferably 2 hours or more, and usually 100 hours or less, preferably 20 hours or less, more preferably 5 hours or less. Within the above range, a sufficient graft rate can be ensured and deterioration of the polymer-based material can be suppressed.

[0057] The method for producing a resin composition according to an embodiment of the present invention may include, in addition to the step related to the radiation-induced graft polymerization described above, a reaction step for imparting functions to the resin composition according to an embodiment of the present invention in accordance with various applications. For example, a resin composition obtained by introducing a spacer portion (E) and an ion-conducting group (Im) into a polymer substrate by radiation graft polymerization may be subjected to an N-alkylation step in which the nitrogen atom of the ion-conducting group (Im) is N-alkylated, or an anion (X - The process may include an ion exchange step in which the cations of the cations are replaced with the desired anions.

[0058] For example, the N-alkylation step may involve alkylating all or some of the nitrogen atoms in the imidazole ring (imidazole derivative) structure of the introduced ion-conducting group (Im). The specific alkylation method and conditions are not particularly limited, and known methods can be appropriately employed. The N-alkylation step according to the present invention is preferably a step of alkylating with an alkyl halide having 1 to 10 carbon atoms.

[0059] The alkyl halide used in the N-alkylation step can be appropriately selected depending on the purpose, but the number of carbon atoms is usually 1 or more and usually 10 or less, preferably 6 or less, and more preferably 3 or less. Examples of the halogen atom of the alkyl halide include chlorine, bromine, and iodine. Specific examples of the alkyl halide include methyl iodide, ethyl iodide, propyl iodide, and isopropyl iodide, with propyl iodide being particularly preferred.

[0060] Solvents used in the N-alkylation step include alcohols such as methanol, ethanol, and propanol; ethers such as dioxane; aromatic hydrocarbons such as toluene and xylene; and aprotic polar solvents such as N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0061] The reaction temperature is usually 5°C or higher, preferably 40°C or higher, and usually 100°C or lower, preferably 95°C or lower. The reaction time is usually 2 hours or more, preferably 24 hours or more, and usually 72 hours or less, preferably 48 hours or less.

[0062] In the N-alkylation step according to the present invention, the specific amount introduced and the like are not particularly limited as long as at least a portion of the nitrogen atoms in the imidazole ring (imidazole derivative) structure are alkylated, but the reaction yield of the N-alkylation is usually 30% or more, preferably 50% or more, and more preferably 70% or more.

[0063] In addition, for example, in the ion exchange step, the resin composition obtained by the radiation graft polymerization step or the N-alkylation step is brought into contact with a solution containing a desired anion, and an anion (X - ) with the desired anion.

[0064] For example, a resin composition that has undergone an N-alkylation process using an alkyl halide usually has a halogen ion as a counter ion of the ion-conducting group (Im). Therefore, when the resin composition is used as an anion exchange electrolyte membrane, it is preferable to replace the halogen ion with a hydroxide ion as the counter ion. In this case, the ion substitution step may be any step in which a resin composition that has been subjected to a step relating to radiation-induced graft polymerization or N-alkylation is brought into contact with a solution containing hydroxide ions, and the specific method, conditions, etc. are not particularly limited, and any known method can be appropriately adopted.

[0065] Examples of solutions containing hydroxide ions include aqueous solutions of sodium hydroxide, potassium hydroxide, and the like. The concentration of hydroxide ions in the solution is usually 0.1 mol / L or more, preferably 0.5 mol / L or more, and usually 5 mol / L or less, more preferably 2 mol / L or less. The immersion temperature is usually 5°C or higher, preferably 20°C or higher, and usually 80°C or lower, preferably 60°C or lower. The immersion time is usually 2 hours or more, preferably 16 hours or more, and usually 48 hours or less, preferably 24 hours or less. In order to complete the ion substitution step of the equilibrium reaction, it is desirable to replace the solution during immersion.

[0066] [Electrochemical Devices] The resin composition according to the above-described embodiment of the present invention can be suitably used as a material in electrochemical devices. In particular, the resin composition according to the embodiment of the present invention can be suitably used as a material for the electrolyte layer and / or electrodes in an electrochemical device including an electrolyte layer and two electrodes arranged opposite each other with the electrolyte layer sandwiched therebetween. Note that the "electrode material" may be any material that forms part of the structure related to the electrode, and also includes a binder for a catalyst or active material.

[0067] The electrochemical device of the present invention may be any device that includes an electrolyte layer and electrodes, and examples thereof include a fuel cell, a metal-air battery, and an electrolytic cell. In particular, the electrochemical device of the present invention is preferably a fuel cell or a metal-air battery. This makes it possible to fully utilize the high ionic conductivity and alkali resistance of the resin composition described above, overcome the problems of low output and durability that have been encountered with conventional fuel cells or metal-air batteries, and provide a highly practical fuel cell or metal-air battery. Hereinafter, the electrochemical device of the present invention will be mainly described in terms of a fuel cell, but is not limited thereto.

[0068] FIG. 1 is a schematic explanatory diagram showing the structure of an electrochemical device (fuel cell) according to an embodiment of the present invention. The electrochemical device 1 according to this embodiment is an anion conducting fuel cell to which a liquid fuel component is directly supplied.

[0069] Fuel components supplied to the electrochemical device 1 include hydrogen, methanol, ammonia, and hydrazines (including hydrazine hydrate, hydrazine anhydride, etc.).

[0070] 1, the electrochemical device 1 has a stack structure in which a plurality of fuel cell cells (unit cells) are stacked, each of which includes a membrane electrode assembly 2, a fuel-side diffusion layer 8, an oxygen-side diffusion layer 9, a fuel supply member 3 disposed on one side (anode side) of the membrane electrode assembly 2, and an air supply member 4 disposed on the other side (cathode side) of the membrane electrode assembly 2. Note that in FIG. 1, only one of the plurality of unit cells is shown as the electrochemical device 1, and the other unit cells are omitted.

[0071] The membrane electrode assembly 2 includes an electrolyte membrane 5 as an electrolyte layer, a fuel-side electrode 6 consisting of a catalyst layer formed on one surface of the electrolyte membrane 5 in the thickness direction (hereinafter simply referred to as "one surface"), and an oxygen-side electrode 7 consisting of a catalyst layer formed on the other surface of the electrolyte membrane 5 in the thickness direction (hereinafter simply referred to as "the other surface"). That is, the membrane electrode assembly 2 has a structure in which a fuel-side electrode 6 and an oxygen-side electrode 7 are arranged opposite each other with the electrolyte membrane 5 interposed therebetween.

[0072] The electrolyte membrane 5 contains an anion component (e.g., hydroxide ion (OH - The electrolyte membrane 5 is not particularly limited as long as it is a layer through which the anion component can migrate and has the function of allowing the anion component to migrate. For example, the electrolyte membrane 5 may be formed using the resin composition described above.

[0073] The fuel-side electrode 6 is composed of a catalyst layer formed from a cell electrode catalyst layer composition containing a binder for forming an electrode catalyst layer and a catalyst.

[0074] The catalyst is not particularly limited, and examples thereof include elements in Groups 8 to 10 (VIII) of the periodic table, such as platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt)), and iron group elements (iron (Fe), cobalt (Co), and nickel (Ni)), and elements in Group 11 (IB) of the periodic table, such as copper (Cu), silver (Ag), and gold (Au). These catalysts can be used alone or in combination of two or more.

[0075] The catalyst may also be supported on a catalyst carrier, such as a porous substance such as carbon or a ceramic material.

[0076] To form the catalyst layer of the fuel-side electrode 6, first, a catalyst ink for the fuel-side electrode 6 (a solution containing a cell electrode catalyst layer composition) is prepared.

[0077] To prepare the catalyst ink for the fuel-side electrode 6, a binder for forming an electrode catalyst layer is added to the above-mentioned catalyst and stirred.

[0078] Here, the above-mentioned resin composition can be used as the binder for forming the electrode catalyst layer. More specifically, the above-mentioned resin composition can be shredded or freeze-pulverized and dispersed in a solvent.

[0079] Examples of the solvent include known solvents such as lower alcohols such as methanol, ethanol, and 1-propanol, ethers such as tetrahydrofuran (THF) and dioxane, ketones such as acetone and methyl ethyl ketone, aprotic polar solvents such as N-methylpyrrolidone, and water. The stirring temperature is, for example, 10 to 30°C, and the stirring time is, for example, 1 to 60 minutes. These solvents can be used alone or in combination of two or more.

[0080] In this way, the catalyst ink for the fuel electrode 6 can be prepared.

[0081] The prepared catalyst ink for the fuel-side electrode 6 is then applied to a material that will serve as the electrode substrate and dried to form a catalyst layer. In this case, a porous body is preferably used as the material that will serve as the electrode substrate, and for example, the electrolyte membrane 5 or the fuel-side diffusion layer 8 may be used. In this case, the catalyst ink for the fuel-side electrode 6 is applied to one side of the electrolyte membrane 5 or the fuel-side diffusion layer 8 and dried to form a catalyst layer.

[0082] Examples of methods for applying the catalyst ink for the fuel-side electrode 6 include known application methods such as spraying, die coating, and ink-jet methods, and preferably, spraying.

[0083] The drying temperature is, for example, 10 to 40°C.

[0084] As a result, the fuel electrode 6 made of the catalyst layer can be obtained.

[0085] Like the fuel-side electrode 6, the oxygen-side electrode 7 is made of a catalyst layer formed from a cell electrode catalyst layer composition containing a binder for forming an electrode catalyst layer and a catalyst.

[0086] The catalyst for the oxygen-side electrode 7 may be the same as the catalyst for the fuel-side electrode 6 described above, or may be formed from a material in which a transition metal is supported on a composite of a complex-forming organic compound and / or a conductive polymer and carbon (hereinafter, this composite is referred to as a "carbon composite").

[0087] Examples of transition metals include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), lanthanum (La), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au). These transition metals can be used alone or in combination of two or more.

[0088] The complex-forming organic compound is an organic compound that forms a complex with a metal atom by coordinating to the metal atom, and examples thereof include pyrrole, porphyrin, tetramethoxyphenylporphyrin, dibenzotetraazaannulene, phthalocyanine, choline, chlorine, phenanthroline, salcomine, benzimidazole, aminobenzimidazole, nicarbazin, diaminomaleonitrile, carbendazim, aminoantipyrine, and the like, or polymers thereof. These complex-forming organic compounds can be used alone or in combination of two or more.

[0089] Examples of conductive polymers include, but are not limited to, polyaniline, polypyrrole, polythiophene, polyacetylene, polyvinylcarbazole, polytriphenylamine, polypyridine, polypyrimidine, polyquinoxaline, polyphenylquinoxaline, polyisothianaphthene, polypyridinediyl, polythienylene, polyparaphenylene, polyflurane, polyacene, polyfuran, polyazulene, polyindole, polydiaminoanthraquinone, etc. These conductive polymers can be used alone or in combination of two or more.

[0090] To form the catalyst layer for the oxygen-side electrode 7, first, a catalyst ink (a solution containing a cell electrode catalyst layer composition) for the oxygen-side electrode 7 is prepared, in the same manner as in the case of forming the catalyst layer for the fuel-side electrode 6 described above.

[0091] The catalyst ink for the oxygen-side electrode 7 is prepared, for example, in the same manner as the catalyst ink for the fuel-side electrode 6 described above.

[0092] The catalyst ink for the oxygen-side electrode 7 may also be prepared, for example, by forming a carbon composite and then supporting a transition metal on the carbon composite.

[0093] To prepare the catalyst ink for the oxygen-side electrode 7, the above-mentioned binder for forming an electrode catalyst layer is added to the above-mentioned catalyst and stirred, as in the case of preparing the catalyst ink for the fuel-side electrode 6. In this way, the catalyst ink for the oxygen-side electrode 7 can be prepared.

[0094] Then, the prepared catalyst ink for the oxygen-side electrode 7 is applied to a material that will become the electrode substrate (for example, the other side of the electrolyte membrane 5 or one side of the oxygen-side diffusion layer 9) in the same manner as the catalyst ink for the fuel-side electrode 6, and dried to form a catalyst layer.

[0095] As a result, the oxygen-side electrode 7 made of the catalyst layer can be obtained.

[0096] To manufacture the membrane electrode assembly 2, the fuel-side electrode 6 and the oxygen-side electrode 7 are bonded to the electrolyte membrane 5. At this time, the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9, which will be described later, may also be bonded.

[0097] There are no particular limitations on the means for joining the fuel-side electrode 6 and the oxygen-side electrode 7 to the electrolyte membrane 5. For example, the electrolyte membrane 5 on which the fuel-side electrode 6 and the oxygen-side electrode 7 are formed may be pressed from both sides in the thickness direction of the electrolyte membrane 5. To pressurize the electrolyte membrane 5, for example, a hydraulic press or the like may be used. At this time, heating may be performed simultaneously with pressing (hot pressing). By hot pressing, the fuel-side electrode 6 and the oxygen-side electrode 7 can be bonded to the electrolyte membrane 5 at a lower pressure. Another example is to stack the fuel-side electrode 6 formed on the fuel-side diffusion layer 8, the electrolyte membrane 5, and the oxygen-side electrode 7 formed on the oxygen-side diffusion layer 9 in this order in a cell, and then join them together using a fixture.

[0098] In this way, the membrane electrode assembly 2 is manufactured.

[0099] The fuel-side diffusion layer 8 supplies fuel to the fuel-side electrode 6, and also has functions such as collecting electrons generated by chemical reactions and protecting the electrolyte membrane 5. The fuel-side diffusion layer 8 is preferably made of a material that is gas permeable and electrically conductive, as well as durable and mechanically strong, such as carbon paper or carbon cloth, or gas-permeable materials containing carbon paper or carbon cloth that has been fluorinated as needed.

[0100] The fuel-side diffusion layer 8 is commercially available, and examples thereof include B-1 Carbon Cloth Type A No wet proofing (manufactured by BASF), ELAT (registered trademark: manufactured by BASF), and SIGRACET (registered trademark: manufactured by SGL).

[0101] The oxygen-side diffusion layer 9 supplies air (oxygen) to the oxygen-side electrode 7, and also has functions related to collecting electrons generated by chemical reactions, protecting the electrolyte membrane 5, and discharging generated water. Examples of the oxygen-side diffusion layer 9 include the gas-permeable materials exemplified for the fuel-side diffusion layer 8.

[0102] As described above, the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9 may have the fuel-side electrode 6 and the oxygen-side electrode 7 formed on their surfaces, respectively, and may function as electrodes, or may be provided separately from the fuel-side electrode 6 and the oxygen-side electrode 7 formed on the electrolyte membrane 5 and have a function related to protecting the electrodes.

[0103] When the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9 have a function of protecting the electrodes, the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9 can be arranged such that the fuel-side diffusion layer 8 is laminated on one side of the electrolyte membrane 5 so as to cover the fuel-side electrode 6, and the oxygen-side diffusion layer 9 is laminated on the other side of the electrolyte membrane 5 so as to cover the oxygen-side electrode 7.

[0104] At this time, there is no particular limitation on the means for laminating the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9 on the electrolyte membrane 5. For example, they may be fixed with a gasket or by applying external pressure (including hot pressing).

[0105] The fuel supply member 3 is made of a gas-impermeable conductive material and supplies liquid fuel to the fuel-side electrode 6. The fuel supply member 3 has grooves formed in a recessed shape, such as a zigzag groove, on its surface. The surface of the fuel supply member 3 on which the grooves are formed faces and contacts the fuel-side electrode 6. As a result, a fuel supply path 10 is formed between one surface of the fuel-side electrode 6 and the other surface of the fuel supply member 3 (the surface on which the grooves are formed) to bring the fuel components into contact with the entire fuel-side electrode 6.

[0106] The fuel supply path 10 has a fuel supply port 11 formed at one end (upper side of the paper in Figure 1) for allowing fuel components to flow into the fuel supply member 3, and a fuel discharge port 12 formed at the other end (lower side of the paper in Figure 1) for discharging the fuel components from the fuel supply member 3.

[0107] The air supply member 4 is made of a gas-impermeable conductive material and supplies air (oxygen) to the oxygen-side electrode 7. The air supply member 4 has grooves formed in a recessed shape, such as a zigzag groove, on its surface. The air supply member 4 may have the grooved surface facing and in contact with the oxygen-side electrode 7. As a result, an air supply path 13 is formed between the other surface of the oxygen-side electrode 7 and one surface of the air supply member 4 (the surface with the grooves) to bring air (oxygen) into contact with the entire oxygen-side electrode 7.

[0108] The air supply path 13 has an air supply port 14 formed at one end (upper side of the paper in Figure 1) for allowing air (oxygen) to flow into the air supply member 4, and an air exhaust port 15 formed at the other end (lower side of the paper in Figure 1) for exhausting air (oxygen) from the air supply member 4.

[0109] An outline of the operation of the electrochemical device 1 described above will be described. In the electrochemical device 1, a fuel component is supplied to the fuel-side electrode 6 through a fuel supply port 11. On the other hand, air (oxygen) is supplied to the oxygen-side electrode 7 through an air supply port .

[0110] On the anode side, liquid fuel passes through fuel supply channel 10 while contacting fuel-side electrode 6. On the other hand, on the cathode side, air (oxygen) passes through air supply channel 13 while contacting oxygen-side electrode 7.

[0111] Then, an electrochemical reaction occurs at each electrode (fuel side electrode 6 and oxygen side electrode 7), generating an electromotive force. [Example]

[0112] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. [Resin composition] (Example 1-1) A 25 μm thick ETFE membrane (manufactured by DuPont) was irradiated with 50 kGy of gamma rays at room temperature under an argon atmosphere, and then immersed in a degassed chloromethylstyrene (CMS) / xylene solution (CMS:xylene = 1:1) in a 60°C thermostatic bath for 2 hours to graft polymerize CMS onto the ETFE main chain (grafting rate 77%).

[0113] The resulting graft membrane was immersed in an ethanol solution of 1,2,4,5-tetramethylimidazole (concentration: 1 M) and reacted for 24 hours in a thermostatic chamber at 60°C. After washing with acetone, it was vacuum dried to obtain a resin composition with chloride ions as counter anions in an N-alkylation reaction yield of 70%. A portion of the resulting resin composition was freeze-pulverized and used as a binder material for forming an electrode catalyst layer.

[0114] The obtained resin composition was immersed in a 1 M potassium hydroxide aqueous solution at room temperature for 16 hours to replace the counter anions with hydroxide ions, and then washed twice with deionized water from which carbon dioxide had been removed by nitrogen bubbling. This immersion procedure was repeated twice more for 30 minutes to obtain a resin composition (anion exchange electrolyte membrane) with hydroxide ions as counter ions.

[0115] The structure of the resin composition in Example 1-1 is shown in the following formula (6). [ka] (In the formula, n and m represent molar ratios.) In Example 1-1, n:m=7:3 in formula (6).

[0116] (Example 1-2) A 25 μm-thick ETFE membrane (manufactured by DuPont) was irradiated with 50 kGy of gamma rays at room temperature under an argon atmosphere, and then immersed in a degassed 2-(4-ethenylphenyl)-1,4,5-trimethyl-1H-imidazole (St-TMIm) / 1,4-dioxane solution (St-TMIm:dioxane = 1:1) in a thermostatic bath at 60°C for 5 hours to graft polymerize St-TMIm onto the ETFE main chain (grafting rate: 55%).

[0117] The resulting graft membrane was immersed in a dioxane solution of propyl iodide (concentration 1 M) and reacted for 24 hours in a thermostatic chamber at 90°C. After washing with acetone, it was immersed in a mixed solution of 1 M aqueous hydrochloric acid and 1,4-dioxane (50 / 50 vol%) to convert the counter anion to chloride ion, then washed with deionized water and dried in vacuum to obtain a resin composition with chloride ion as counter anion in a 100% N-alkylation reaction yield. The obtained resin composition was made into an anion exchange electrolyte membrane with hydroxide ions as counter ions by the same procedure as in Example 1-1.

[0118] The structure of the resin composition in Example 1-2 is shown in the following formula (7). [ka]

[0119] (Comparative Example 1-1) A 25 μm thick ETFE membrane (manufactured by DuPont) was irradiated with 50 kGy of gamma rays at room temperature under an argon atmosphere, and then immersed in a degassed chloromethylstyrene (CMS) / xylene solution (CMS:xylene = 1:1) in a 60°C thermostatic bath for 2 hours to graft polymerize CMS onto the ETFE main chain (grafting rate 70%).

[0120] The resulting grafted membrane was immersed in an aqueous trimethylamine solution (concentration: 30 wt%) and allowed to react at room temperature for 16 hours. After washing with deionized water, it was immersed in 1 M hydrochloric acid for 24 hours, and then immersed in deionized water and washed for 2 hours to obtain a resin composition with chloride ions as counter ions with a 100% quaternization reaction yield. A portion of the resulting resin composition was freeze-pulverized and used as a binder material for forming an electrode catalyst layer.

[0121] The obtained resin composition was made into an anion exchange electrolyte membrane with hydroxide ions as counter ions by the same procedure as in Example 1-1.

[0122] The structure of the resin composition in Comparative Example 1-1 is shown in the following formula (8). [ka]

[0123] (Comparative Example 1-2) A 25 μm thick ETFE membrane (manufactured by DuPont) was irradiated with 50 kGy of gamma rays at room temperature under an argon atmosphere, and then immersed in a degassed chloromethylstyrene (CMS) / xylene solution (CMS:xylene = 1:1) in a 60°C thermostatic bath for 2 hours to graft polymerize CMS onto the ETFE main chain (grafting rate 70%).

[0124] The obtained graft membrane was immersed in an ethanol solution of 1,2-dimethylimidazole (concentration 2 M) and reacted for 4 hours in a thermostatic bath at 60°C. After washing with acetone, it was vacuum dried to obtain a resin composition with chloride ions as counter anions in an N-alkylation reaction yield of 57%.

[0125] The obtained resin composition was made into an anion exchange electrolyte membrane with hydroxide ions as counter ions by the same procedure as in Example 1-1.

[0126] The structure of the resin composition in Comparative Example 1-2 is shown in the following formula (9). [ka] (In the formula, n and m represent molar ratios.) In Comparative Example 1-2, n:m=6:4 in formula (9).

[0127] (Comparative Examples 1-3) A 25 μm thick ETFE membrane (manufactured by DuPont) was irradiated with 50 kGy of gamma rays under an argon atmosphere at room temperature, and then immersed in a degassed 2-(4-ethenylphenyl)-1-methyl-1H-imidazole (St-Im) / 1,4-dioxane solution (St-Im:dioxane=1:1) in a thermostatic bath at 60°C for 5 hours to graft polymerize St-Im onto the ETFE main chain (grafting rate: 47%).

[0128] The resulting graft membrane was immersed in a dioxane solution of propyl iodide (concentration 1 M) and reacted for 24 hours in a thermostatic chamber at 90°C. After washing with acetone, it was immersed in a mixed solution of 1 M aqueous hydrochloric acid and 1,4-dioxane (50 / 50 vol%) to convert the counter anion to chloride ion, then washed with deionized water and dried in vacuum to obtain a resin composition with chloride ion as counter anion in a 100% N-alkylation reaction yield.

[0129] The obtained resin composition was made into an anion exchange electrolyte membrane with hydroxide ions as counter ions by the same procedure as in Example 1-1.

[0130] The structure of the resin composition in Comparative Example 1-3 is shown in the following formula (10). [ka]

[0131] For the anion exchange electrolyte membranes produced in Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-3, measurements related to five evaluation criteria (grafting rate, ion exchange capacity (IEC), water content, electrical conductivity, and alkaline durability) were obtained, and the performance of each anion exchange electrolyte membrane was evaluated.

[0132] In evaluating such anion exchange membranes, it is ideal to use all hydroxide ions as counterions. However, the counterions, hydroxide ions, react quickly with carbon dioxide in the atmosphere and convert to bicarbonate ions. Therefore, to obtain stable measurement values, the washing and electrical conductivity measurements after immersion in the basic solution are carried out in deionized water from which the carbon dioxide has been removed by nitrogen bubbling.

[0133] Each measurement value was determined as follows. (1) Graft rate (%) If the polymer base material is the main chain and the part grafted with the starting material is the graft chain, the weight ratio of the graft chain to the main chain is calculated by the following formula: graft ratio (X dg It is expressed as [% by weight].

[0134] X dg = 100(W2-W1) / W1 W1: Dry weight before grafting (g) W2: Dry weight after grafting (g)

[0135] (2) Ion exchange capacity (mmol / g) The ion exchange capacity (IEC) of an anion exchange membrane is expressed by the following formula:

[0136] IEC = [n (basic group) obs ] / W3(mM / g) [n(basic group) obs ]: Amount of basic groups in the anion exchange membrane (mM) W3: Dry weight of the anion exchange membrane (g)

[0137] [n(basic group) obs The measurement of is carried out according to the following procedure. An anion exchange electrolyte membrane in the hydroxide (hereinafter referred to as "OH type") state is immersed in an accurately measured volume of 0.1 M hydrochloric acid solution at room temperature for 12 hours to completely convert it to the chloride (hereinafter referred to as "Cl type") state, and then the concentration of the remaining hydrochloric acid solution is back-titrated with 0.1 M NaOH to determine the basic group concentration of the anion exchange electrolyte membrane.

[0138] (3) Moisture content (%) A Cl-type or OH-type anion exchange electrolyte membrane stored in water at room temperature is taken out, the water on the surface is lightly wiped off, and the weight is measured (W5 (g)). This membrane is vacuum dried at 40°C for 16 hours, and then the weight is measured to determine the dry weight W4 (g) of the anion exchange electrolyte membrane, and the water content is calculated from W5 and W4 using the following formula.

[0139] Moisture content = 100(W5-W4) / W4

[0140] (4) Electrical conductivity (S / cm) For AC measurements, a membrane resistance measurement cell consisting of platinum electrodes and a HIOKI LCR meter 3522 were used. An anion exchange electrolyte membrane in a saturated swollen state in water at room temperature was taken out, sandwiched between platinum electrodes, and immersed in deionized water at 60°C for 2 minutes, after which the membrane resistance (Rm) was measured based on impedance. The conductivity (standard) of the anion exchange electrolyte membrane was then calculated using the following equation.

[0141] κ = 1 / Rm d / S κ: Electrical conductivity of the anion-conducting electrolyte membrane (S / cm) d: Thickness of the anion exchange membrane (cm) S: Current-carrying area of ​​the anion-conducting electrolyte membrane (cm 2 )

[0142] The electrical conductivity of the resin composition (anion exchange electrolyte membrane) according to the embodiment of the present invention is usually 40 mS / cm or more, and preferably 50 mS / cm or more. When the electrical conductivity of the resin composition is in this range, it can be made sufficiently practical, particularly as an anion exchange electrolyte membrane.

[0143] (5) Alkali durability (retention rate (%) of conductivity after immersion in alkaline solution for 200 hours) Each anion exchange electrolyte membrane was immersed in 1 M KOH heated to 80°C for 200 hours, and the conductivity of the anion exchange electrolyte membrane after immersion was determined. The conductivity retention rate (residual rate) was then calculated using the following formula to evaluate the alkali durability.

[0144] Maintenance rate = conductivity (after 200 hours immersion) / conductivity (standard) x 100

[0145] The resin composition (anion exchange electrolyte membrane) according to the embodiment of the present invention has a conductivity retention rate related to alkali durability of usually 60% or more, preferably 70% or more. When the conductivity retention rate of the resin composition is in this range, the resin composition can have sufficient practicality, particularly as an anion exchange electrolyte membrane.

[0146] Table 1 shows the grafting rate, IEC, water content, conductivity, and conductivity retention rate after immersion in 1 M KOH heated to 80°C for 200 hours of the anion exchange electrolyte membranes produced in Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-3.

[0147] JPEG0007825289000015.jpg75166

[0148] From the results in Table 1, it can be confirmed that the resin compositions (anion exchange electrolyte membranes) produced in Examples 1-1 and 1-2 all have good electrical conductivity, water absorption characteristics, and alkali durability.

[0149] In particular, in the evaluation of alkaline durability, the resin composition of Comparative Example 1-1 containing trimethylammonium salt as the ion-conducting group showed gelation of the film 48 hours after immersion. Furthermore, the resin composition of Comparative Example 1-2, in which the 4th and 5th positions were not protected, showed a conductivity retention rate of 1%, whereas the resin composition of Example 1-1, in which the 4th and 5th positions of the ion-conducting group (Im) were protected with methyl groups, showed a significantly improved conductivity retention rate of 95%. Similarly, a comparison of Comparative Example 1-3 and Example 1-2 also revealed that the conductivity retention rate improved approximately threefold, from 23% to 74%.

[0150] Therefore, the results in Table 1 show that the resin composition according to the embodiment of the present invention has functions related to ion conductivity and alkali resistance, and is particularly suitable for practical use as an anion exchange electrolyte membrane.

[0151] [Electrochemical Devices] As examples and comparative examples of electrochemical devices according to embodiments of the present invention, membrane electrode assemblies and fuel cells were produced. Example 2 [1] Preparation of catalyst ink for the fuel electrode A paste prepared by dispersing a platinum-ruthenium-carbon catalyst (ruthenium content: 30 wt %, platinum content: 23 wt %) and carbon black (VULCAN (registered trademark) XC-72R) in distilled water was mixed with the resin composition of Example 1-1 dispersed in isopropanol so that the platinum:carbon:binder mixture ratio was 1.00:2.50:1.04, and the mixture was then dispersed using ultrasonic waves at 10°C for 60 minutes to prepare a catalyst ink for the fuel-side electrode.

[0152] [2] Preparation of catalytic ink for the oxygen electrode A paste prepared by dispersing a platinum-carbon catalyst (platinum content 46 wt%) and carbon black (VULCAN (registered trademark) XC-72R) in distilled water and the resin composition of Example 1-1 dispersed in isopropanol were mixed so that the platinum:carbon:binder mixture ratio was 1.00:1.20:0.55, and the mixture was then dispersed using ultrasonic waves at 10°C for 60 minutes to prepare a catalyst ink for the oxygen-side electrode.

[0153] [3] Application and drying of each catalyst ink The catalyst ink for the fuel electrode and the oxygen electrode was sprayed onto a gas diffusion layer (SIGRACET (registered trademark) 25BC). After drying at 25°C, a catalyst area of ​​5 cm was obtained. 2 , a fuel electrode with a thickness of 150 μm and a catalyst area of ​​5 cm 2 An oxygen-side electrode having a thickness of 150 μm was formed. Here, the gas diffusion layer corresponds to the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9 described above, and the fuel-side electrode and the oxygen-side electrode in this embodiment are formed on the fuel-side diffusion layer 8 and the oxygen-side diffusion layer 9, respectively, and are integrated with each other.

[0154] [4] Joining the fuel-side electrode and oxygen-side electrode with the electrolyte membrane (preparation of membrane electrode assembly) The prepared fuel-side electrode, oxygen-side electrode, and resin composition of Example 1-1 (anion exchange electrolyte membrane) were each immersed in a 1 M KOH aqueous solution in separate containers for 1 hour, and after wiping off excess KOH aqueous solution from the surfaces, the fuel-side electrode, electrolyte membrane (anion exchange electrolyte membrane), and oxygen-side electrode were stacked on top of each other in this order on the fuel cell, and the assembly bolts of the fuel cell were tightened with a torque of 8 Nm to join them.

[0155] [5] Fuel cell manufacturing A fuel supply member and an air supply member were provided on the obtained membrane electrode assembly to form a single cell unit fuel cell having the structure shown in FIG.

[0156] (Comparative Example 2) A membrane electrode assembly and a fuel cell were obtained in the same manner as in Example 2, except that in preparing the catalyst ink for the fuel-side electrode and the catalyst ink for the oxygen-side electrode, the resin composition of Comparative Example 1-1 was mixed instead of using the resin composition of Example 1-1.

[0157] Using the fuel cells of the single cell units obtained in Example 2 and Comparative Example 2, evaluations were made on output and durability. (1) Fuel cell output test Using the fuel cells of the single cell units obtained in Example 2 and Comparative Example 2, an output test was carried out. The fuel cell temperature was set to 60°C, and in Example 2, hydrogen gas was supplied to the anode side at 50°C at 500 ml / min, and oxygen at 51°C was supplied to the cathode side at 500 ml / min to generate electricity. On the other hand, in Comparative Example 2, hydrogen gas was supplied to the anode side at 58°C at 500 ml / min, and oxygen at 59°C was supplied to the cathode side at 500 ml / min to generate electricity. Current density: 0 mA / cm 2 The voltage was measured as the current was gradually increased from 0.01 V, and the output power density at each current value was calculated from the obtained values.

[0158] Figure 2 shows the measurement results obtained in the output test, where Figure 2A shows a graph of current density vs. voltage, and Figure 2B shows a graph of current density vs. output power density. As shown in FIG. 2, in the fuel cell of Comparative Example 2 in which the resin composition of Comparative Example 1-1 was used as a binder for forming the electrode catalyst layer of the membrane electrode assembly, the maximum output power density was 172 mW / cm 2 In contrast, in the fuel cell of Example 2 in which the resin composition of Example 1-1 was used as a binder for forming the electrode catalyst layer of the membrane electrode assembly, the maximum output power density was 804 mW / cm 2 It was. Therefore, it can be seen that the power generation performance of the fuel cell of Example 2, in which the resin composition of Example 1-1 was used as a material for the electrolyte layer (electrolyte membrane) and electrodes in an electrochemical device (fuel cell), was improved by about 5 times compared to the power generation performance of the fuel cell of Comparative Example 2, in which the resin composition of Comparative Example 1-1 was used as a material for the electrolyte layer and electrodes. Furthermore, as in Example 2, it was found that using the resin composition according to an embodiment of the present invention for both the electrolyte layer (electrolyte membrane) and the binder for forming the electrode catalyst layer, and matching the compositions of the electrolyte membrane and the binder for forming the electrode catalyst layer, is important for improving the power generation performance of the electrochemical device (fuel cell) from the standpoint of compatibility, etc.

[0159] (2) Fuel cell durability test The fuel cells of the single cell units obtained in Example 2 and Comparative Example 2 were used to carry out a durability test. The fuel cell temperature was set to 60°C, and in Example 2, hydrogen gas was supplied to the anode side at 50°C at 100 ml / min, and oxygen gas at 51°C was supplied to the cathode side at 100 ml / min to generate electricity, and the current density was set to 50 mA / cm. 2 On the other hand, in Comparative Example 2, hydrogen gas was supplied to the anode side at 58°C at 100 ml / min, and oxygen gas at 59°C was supplied to the cathode side at 100 ml / min to generate electricity, and the current density was set to 50 mA / cm. 2 The voltage was measured when the voltage was fixed at 0.5 V, and the voltage drop rate was calculated.

[0160] Fig. 3 shows the measurement results obtained in the durability test, showing the change in voltage over time at a constant current value (evaluation time-voltage graph). As shown in FIG. 3, the cell voltage of the fuel cell of Comparative Example 2 decreased as the evaluation time increased, whereas the fuel cell of Example 2 was able to maintain 95% of the initial cell voltage even after 440 hours.

[0161] The above-described embodiments are examples of the resin composition, the method for producing the resin composition, and the electrochemical device. The resin composition, the method for producing the resin composition, and the electrochemical device according to the present invention are not limited to the above-described embodiments, and the resin composition, the method for producing the resin composition, and the electrochemical device according to the above-described embodiments may be modified within the scope of the claims.

[0162] In the above-described embodiment, the resin composition and the method for producing the resin composition of the present invention have been described as being primarily used as materials for electrolyte layers (electrolyte membranes) and electrodes (binders for forming electrode catalyst layers) in electrochemical devices, and as methods for producing the same, but the present invention is not limited thereto. For example, the resin composition and the method for producing the resin composition of the present invention can be used as materials and methods for producing the same in various fields, taking advantage of their high ionic conductivity and alkali resistance. For example, the resin composition of the present invention may be used in ion exchange membranes, reverse osmosis membranes, etc.

[0163] In the above-described embodiments, the electrochemical device of the present invention has been mainly described as a fuel cell, but is not limited thereto. For example, the electrochemical device of the present invention may be any device that uses a resin composition with high ionic conductivity and alkali resistance as an electrolyte layer (electrolyte membrane) and electrode material (including a catalyst and a binder for an active material), and may also be applied to other electrochemical devices such as metal-air batteries and electrolytic cells. In a metal-air battery, the fuel-side electrode 6 in the electrochemical device shown in the embodiment is replaced with an active material such as zinc, aluminum, magnesium, or lithium. [Industrial Applicability]

[0164] The resin composition and the method for producing the resin composition of the present invention are used as a resin composition imparted with functions relating to ion conductivity and alkali resistance, and as a method for producing the same. The electrochemical device of the present invention is used as an electrochemical device comprising an electrolyte layer and electrodes, and is particularly suitable for use as a fuel cell or a metal-air battery. [Explanation of symbols]

[0165] 1 electrochemical device, 2 membrane electrode assembly, 3 fuel supply member, 4 air supply member, 5 electrolyte membrane (electrolyte layer), 6 fuel side electrode, 7 oxygen side electrode, 8 fuel side diffusion layer, 9 oxygen side diffusion layer, 10 fuel supply path, 11 fuel supply port, 12 fuel outlet, 13 air supply path, 14 air supply port, 15 air outlet

Claims

1. It contains a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), The spacer moiety (E) or the spacer moiety (E) and the ion-conducting group (Im) in the following formula (1) are introduced into the polymer substrate by radiation-induced graft polymerization, The conductivity is 40 mS / cm or more, The resin composition is characterized in that it maintains electrical conductivity of 70% or more after being immersed in a 1M aqueous potassium hydroxide solution heated to 80°C for 200 hours. 【Chemistry 1】 (In formula (1), E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R １ ~R ５ are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains a hydrogen atom, a halogen atom, or a heteroatom; X － indicates an anion.) 【Chemistry 2】 (In formula (2), R 6 is a carbon chain having 1 to 10 carbon atoms, which carbon chain contains hydrogen, halogen or a heteroatom, and 1 is an integer of 0 to 5.)

2. Among the structural units represented by the formula (1), in the structural unit represented by the following formula (3), R １ and R ３ The resin composition according to claim 1, wherein at least one of the following has 2 or more carbon atoms: 【Transformation 3】 (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative substituted with at least one hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; R １ , R ３ , R ４ , R ５ are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains a hydrogen atom, a halogen atom, or a heteroatom; X － indicates an anion.)

3. It contains a structural unit represented by the following formula (3), R １ and R ３ wherein at least one of the following has 2 or more carbon atoms: 【Chemistry 4】 (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative substituted with at least one hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; R １ , R ３ , R ４ , R ５ are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains a hydrogen atom, a halogen atom, or a heteroatom; X － indicates an anion.)

4. A method for producing a resin composition containing a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), The method includes a step of introducing a spacer portion (E) or a spacer portion (E) and an ion-conducting group (Im) in the following formula (1) into a polymer substrate by radiation-induced graft polymerization: The resin composition has a conductivity of 40 mS / cm or more, and wherein the electrical conductivity is maintained at 70% or more after immersion in a 1 M aqueous potassium hydroxide solution heated to 80°C for 200 hours. 【Transformation 5】 (In formula (1), E is a spacer moiety and represents a benzene ring, a benzene derivative at least one of which is substituted with a hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; Im represents an ion-conducting group containing an imidazole ring; R １ ~R ５ are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains a hydrogen atom, a halogen atom, or a heteroatom; X － indicates an anion.) 【Transformation 6】 (In formula (2), R 6 is a carbon chain having 1 to 10 carbon atoms, which carbon chain contains hydrogen, halogen or a heteroatom, and 1 is an integer of 0 to 5.)

5. An electrochemical device comprising an electrolyte layer and two electrodes disposed opposite each other with the electrolyte layer interposed therebetween, An electrochemical device, characterized in that the electrolyte layer and / or the electrode comprises the resin composition according to any one of claims 1 to 3.

6. 6. The electrochemical device according to claim 5, which is a fuel cell or a metal-air battery.

7. A method for producing a resin composition containing a structural unit represented by the following formula (3): The method includes a step of introducing a spacer moiety (E) or a spacer moiety (E) and an ion-conducting group (Im) in the following formula (3) by radiation-induced graft polymerization: In the following formula (3), R １ and R ３ wherein at least one of the carbon atoms in the alkyl group is 2 or more. 【Transformation 7】 (In the formula, E is a spacer moiety and represents a benzene ring, a benzene derivative substituted with at least one hydrocarbon group having 1 to 6 carbon atoms, or a carbon chain having 2 or more carbon atoms which may contain a heteroatom; R １ , R ３ , R ４ , R ５ are each independently a carbon chain having 1 to 10 carbon atoms, and this carbon chain contains a hydrogen atom, a halogen atom, or a heteroatom; X － indicates an anion.)

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