JP2005239850A - Ionically conductive macromolecular compound and method for producing the same, and article using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ionically conductive macromolecular compound(polymeric material) having ionic conductivity at the same level as fluoropolymers despite being a nonfluoroaromatic polymer, excellent in heat resistance and processability, particularly useful as an ionically conductive membrane, or the like. <P>SOLUTION: The ionically conductive macromolecular compound bears carboxy groups and/or derivatives thereof together with sulfo groups and/or derivatives thereof on its aromatic main chain. Preferably, this macromolecular compound also bears cyano groups. Articles including ionically conductive membranes, composites, fuel cells and adhesives each using the ionically conductive macromolecular compound are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ionic group-containing polymer compound useful as a polymer electrolyte membrane or the like and a method for producing the same. Further, the present invention relates to articles such as ion conductive membranes, composites, fuel cells, and adhesives using ion conductive polymer compounds.

  As an example of an electrochemical device using a polymer solid electrolyte as an ionic conductor instead of a liquid electrolyte, a water electrolyzer and a fuel cell can be raised. The polymer membrane used for these must be sufficiently stable chemically, thermally, electrochemically and mechanically with proton conductivity as a cation exchange membrane. For this reason, perfluorocarbon sulfonic acid membranes, typically “Nafion (registered trademark)” manufactured by DuPont of the United States, have been used. However, when the Nafion membrane is operated under conditions exceeding 100 ° C., the moisture content of the membrane is drastically lowered, and the membrane is significantly softened. In addition, even when operating under low humidification conditions, the moisture content of the membrane decreases, and sufficient power generation characteristics cannot be obtained. Furthermore, it is pointed out that the cost of the membrane is too high as an obstacle to the establishment of fuel cell technology.

In order to overcome such drawbacks, various polymer electrolyte membranes in which a sulfonic acid group is introduced into a non-fluorinated aromatic ring-containing polymer have been studied. As the polymer skeleton, aromatic polyarylene ether compounds such as aromatic polyarylene ether ketones and aromatic polyarylene ether sulfones can be considered as promising structures in consideration of heat resistance and chemical stability. A sulfonated polyarylethersulfone (for example, see Non-patent Document 1), a sulfonated polyetheretherketone (for example, see Patent Document 1), sulfonated polystyrene, and the like have been proposed. However, sulfonic acid groups introduced onto aromatic rings by sulfonation reaction of these polymers generally tend to be easily removed by heat, and as a method for improving this, sulfonic acid groups are introduced onto electron-withdrawing aromatic rings. A sulfonated polyarylene ether sulfone compound having high thermal stability has been proposed by polymerization using monomers (see, for example, Patent Document 2). In this case, since the reactivity of a monomer is low, the problem which requires superposition | polymerization for a long time in order to obtain a polymer has arisen (for example, refer nonpatent literature 2). These non-fluorinated polymer electrolytes may have a low sulfonic acid group acidity, and in order to develop proton conductivity at the same level as that of the fluorinated polymer electrolyte membranes, the non-fluorinated polymer electrolytes are more suitable than those of fluorinated polymer electrolytes. It is necessary to introduce many sulfonic acid groups into the polymer chain. However, when the amount of the sulfonic acid group is increased, the swelling of the membrane when wetted tends to increase. In particular, there is a problem that becomes an obstacle at the time of high-temperature power generation, and a more excellent membrane is required.
JP-A-6-93114 (pages 15-17) US Patent Application Publication No. 2002/0091225 (page 1-2) Journal of Membrane Science, (Netherlands) 1993, 83, p. 211-220 ACS Polymer Preprints, (USA), 2000, 41 (2), P.C. 1388-1389

  The object of the present invention is to provide proton conductivity at the same level as that of a fluorinated polymer while being a non-fluorinated polymer, have good processability and moisture resistance, and are wet even when a polymer electrolyte membrane is formed. An object of the present invention is to provide a sulfonic acid group-containing polymer compound capable of exhibiting excellent dimensional stability at the time, and further, an ion conductive membrane utilizing the characteristics of the sulfonic acid group-containing polymer compound, and the ion conductive membrane And an electrode, a fuel cell using the composite, an adhesive, and the like.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by devising the polymer structure of a polymer electrolyte in which a sulfonic acid is introduced onto an aromatic ring.

  That is, the present invention employs the following configurations (1) to (11).

  (1) An ion conductive polymer compound having a carboxyl group and / or a derivative thereof together with a sulfonic acid group and / or a derivative thereof on an aromatic main chain.

  (2) The ion conductive polymer compound according to the first invention, which includes structural units represented by general formula (1) and general formula (2).

ただし、Ａｒ、Ａｒ’は同一でも異なっていても良い２価の芳香族基、ＸはＨまたは１価のカチオン種、ＹはＯＨ、ＯＭ（Ｍは１価のカチオン種）、ＮＲＲ’（Ｒ、Ｒ’は独立してＨ、アルキル基から選ばれる）を示す。

However, Ar and Ar ′ may be the same or different divalent aromatic groups, X is H or a monovalent cation species, Y is OH, OM (M is a monovalent cation species), NRR ′ (R , R ′ is independently selected from H and an alkyl group.

  (3) The ion conductive polymer compound according to the first or second invention, wherein the polymer further has a cyano group on the aromatic main chain.

  (4) The ion-conducting polymer compound according to the third invention, which comprises the structural unit represented by the general formula (3) together with the structural unit represented by the general formulas (1) and (2). .

  (5) The ion conductive polymer compound according to any one of the first to fourth inventions, wherein the sulfonic acid group content is in the range of 0.3 to 3.5 mg / g.

  (6) A composition comprising 50 to 100% by mass of the ion conductive polymer compound according to any one of the first to fifth inventions.

  (7) An ion conductive membrane comprising the ion conductive polymer compound according to any one of the first to fifth inventions and / or the composition according to the sixth invention.

  (8) A composite comprising the ion conductive membrane according to the seventh invention and an electrode.

  (9) A fuel cell comprising the composite according to the eighth invention.

  (10) An adhesive comprising the ion conductive polymer compound according to any one of the first to fifth inventions.

  (11) The ion conductive polymer according to any one of the first to fifth inventions by treating the polymer compound containing the constituents represented by the general formulas (1) and (3) with an acidic compound. A process for obtaining a compound.

  Although the ionic group-containing polymer compound of the present invention is a non-fluorine polymer, it has proton conductivity of the same level as that of a fluorine polymer, and not only ion conductivity but also heat resistance, workability and dimensional stability. Is excellent. For this reason, the outstanding performance as polymer electrolytes, such as a fuel cell, can be shown. The ionic group-containing polymer compound of the present invention is also characterized by low methanol permeability, and is useful as a polymer electrolyte membrane for direct methanol fuel cells.

Hereinafter, the present invention will be described in detail.
The present invention provides heat resistance, processability, and ion conductivity by a polymer compound having a specific structure that simultaneously contains a carboxyl group and / or a derivative thereof together with a sulfonic acid group and / or a derivative thereof on an aromatic main chain. The present invention provides an excellent polymer material particularly useful as an ion conductive membrane. Examples of the polymer skeleton of the ionic group-containing polymer compound of the present invention include polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, polyarylene polymer, polyphenylquinoxaline, and polyaryl ketone. , Polymers containing at least one component such as polyetherketone, polybenzoxazole, polybenzthiazole, and polyimide. Polysulfone, polyethersulfone, polyetherketone, and the like referred to here are generic names for polymers having a sulfone bond, an ether bond, and a ketone bond in their molecular chains. Polyetherketoneketone, polyetheretherketone, In addition to a polymer skeleton structure called polyether ether ketone ketone, polyether ketone ether ketone ketone, polyether ketone sulfone, etc., the specific polymer structure is not limited.

  Among the aromatic polymers, polymers such as polysulfone, polyethersulfone, polyphenylene sulfide, polyphenylene sulfide sulfone, and polyether ketone are preferable in terms of processability and stability. It is particularly preferable that the polymer is an aromatic polymer containing a constituent represented by the general formula (2).

ただし、Ａｒ、Ａｒ’は同一でも異なっていても良い２価の芳香族基、ＸはＨまたは１価のカチオン種であり、Ｎａ、Ｋ等の金属塩が例示される。Ｙは水酸基やＯＭで表される誘導体で、Ｍは１価のカチオン種であり、Ｎａ，Ｋ等の金属塩が例示される他、ＮＲＲ’（Ｒ、Ｒ’は独立してＨ，アルキル基から選ばれる）で示される各種アンモニウムカチオンを示す。

However, Ar and Ar ′ are the same or different divalent aromatic groups, X is H or a monovalent cation species, and metal salts such as Na and K are exemplified. Y is a derivative represented by hydroxyl group or OM, M is a monovalent cation species, and examples thereof include metal salts such as Na and K, and NRR ′ (R and R ′ are independently H and alkyl groups). Various ammonium cations selected from

  The ionic group-containing polymer compound of the present invention preferably further contains a cyano group on the aromatic main chain. This is because the ease of aggregation of the polymer main chain by the cyano group improves the dimensional stability when wet as an ionic group-containing polymer, and can also be used as a precursor structure giving a carboxyl group or a carboxyl group derivative structure.

  The cyano group present in the ionic group-containing polymer of the present invention is preferably composed of a constituent represented by the following general formula (3).

ただし、Ａｒ’’は２価の芳香族基を示す。

However, Ar '' represents a divalent aromatic group.

  The ionic group-containing polymer compound part of the present invention may contain structural units other than those represented by the above general formula (1), general formula (2), and general formula (3). At this time, the structural units other than those represented by the general formula (1), the general formula (2), and the general formula (3) may be 50% by mass or less of the polyarylene ether into which the sulfonic acid of the present invention is introduced. preferable. By setting it as 50 mass% or less, it can be set as the composition which utilized the characteristic of the ionic group containing high molecular compound of this invention.

  The ionic group-containing polymer compound of the present invention preferably has a sulfonic acid group content in the range of 0.3 to 3.5 meq / g. When it is less than 0.3 meq / g, there is a tendency that sufficient ion conductivity is not exhibited when used as an ion conductive membrane, and when it is greater than 3.5 meq / g, the ion conductive membrane is not heated and humidified. When the conditions are met, membrane swelling tends to be too large to be suitable for use. The sulfonic acid group content can be calculated from the polymer composition. In addition, Preferably it is 1.0-3.0 meq / g.

  In the ionic group-containing polymer compound of the present invention, the introduction of the unit containing a sulfonic acid group can be carried out by utilizing a polymerization reaction including a monomer containing a sulfonic acid group, and the precursor polymer is converted into an appropriate sulfone. It can also be carried out by sulfonation using a fluorinating reagent. When utilizing the polymerization reaction containing the monomer containing a sulfonic acid group, it can superpose | polymerize by the aromatic nucleophilic substitution reaction which contains the compound represented, for example by following General formula (4) as a monomer. Specific examples of the compound represented by the general formula (4) include 3,3′-disulfo-4,4′-dichlorodiphenylsulfone, 3,3′-disulfo-4,4′-difluorodiphenylsulfone, 3, 3'-disulfo-4,4'-dichlorodiphenyl ketone, 3,3'-disulfo-4,4'-difluorodiphenyl sulfone, and those in which their sulfonic acid group is converted to a salt with a monovalent cationic species Can be mentioned. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto.

ただし、Ｙはスルホン基またはケトン基、Ｘは１価のカチオン種、Ｚは塩素またはフッ素を示す。

Y represents a sulfone group or a ketone group, X represents a monovalent cation species, and Z represents chlorine or fluorine.

  In the ionic group-containing polymer compound of the present invention, the introduction of a unit containing a carboxyl group and / or a derivative thereof can be performed using, for example, a polymerization reaction including a monomer containing a carboxyl group and / or a derivative thereof. it can. When utilizing a polymerization reaction including a monomer containing a carboxyl group, for example, an aromatic nucleophilic substitution reaction using an aromatic dichloro compound or aromatic difluoro compound containing a carboxyl group or a carboxylate as a part of the activated dihalogen compound. Specific examples of the structure include 3-carboxydifluorodiphenyl sulfone. In the aromatic nucleophilic substitution reaction, an aromatic diol containing a carboxyl group or a carboxylate can also be used as part of the aromatic diol component.

  In the ionic polymer compound of the present invention, the introduction of a unit containing a cyano group can be carried out by selecting a monomer containing a cyano group as a part of the monomer to be used, which is represented by the following structural formula (5). Can be polymerized by an aromatic nucleophilic substitution reaction containing the compound as a monomer. Examples of the compound represented by the general formula (5) include 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2,4-dichlorobenzonitrile, 2,4-difluorobenzonitrile, and the like. it can. In the present invention, the above 2,6-dichlorobenzonitrile and 2,4-dichlorobenzonitrile are in an isomer relationship, and any of them is used, good ion conductivity, heat resistance, workability and dimensional stability. Can be achieved. The reason is considered that both monomers are excellent in reactivity and that the structure of the whole molecule is made harder by constituting a small repeating unit.

ただし、Ｚは塩素またはフッ素を示す。

However, Z shows chlorine or a fluorine.

  In the above-described aromatic nucleophilic substitution reaction, various activated difluoroaromatic compounds and dichloroaromatic compounds can be used in combination with the compounds represented by the general formulas (4), (5) and the like as monomers. Examples of these compounds include 4,4′-dichlorodiphenyl sulfone, 4,4′-difluorodiphenyl sulfone, 4,4′-difluorobenzophenone, 4,4′-dichlorobenzophenone, decafluorobiphenyl, and the like. However, other aromatic dihalogen compounds, aromatic dinitro compounds, aromatic dicyano compounds and the like that are active in aromatic nucleophilic substitution can also be used.

  In addition, Ar, Ar ′, and Ar ″ in the constituents represented by the above general formulas (1), (2), and (3) are generally represented by the above general formula (4) in aromatic nucleophilic substitution polymerization. , (5), etc. The structure is introduced from an aromatic diol component monomer used together with the compound represented by, for example, 4,4′-biphenol, bis (4- Hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) ) Butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxy-3,5- Methylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 9,9-bis (4-hydroxyphenyl) Fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcin, 1,6-naphthalenediol, 2,7-naphthalene Diols, bis (4-hydroxyphenyl) ketones and the like can be mentioned. In addition, various aromatic diols that can be used for polymerization of polyarylene ether compounds by aromatic nucleophilic substitution reaction can also be used. Here, carboxyl group and / or derivative thereof Aromatic diols containing can also be used with these aromatic diols. These aromatic diols can be used alone, it is also possible to use a plurality of aromatic diols.

  When the ionic group-containing polymer compound of the present invention is polymerized by an aromatic nucleophilic substitution reaction, the activated difluoroaromatic compound and / or the dihalogenated aromatic compound and the aromatic diol containing the compound exemplified above are used as a base. A polymer can be obtained by reacting in the presence of a functional compound. The polymerization can be carried out in the temperature range of 0 to 350 ° C., but is preferably 50 to 250 ° C. When the temperature is lower than 0 ° C., the reaction does not proceed sufficiently, and when the temperature is higher than 350 ° C., the polymer tends to be decomposed. The reaction can be carried out in the absence of a solvent, but is preferably carried out in a solvent. Examples of the solvent that can be used include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, diphenyl sulfone, sulfolane, and the like. And any solvent that can be used as a stable solvent in the aromatic nucleophilic substitution reaction. These organic solvents may be used alone or as a mixture of two or more. Examples of the basic compound include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and the like, and those that can convert an aromatic diol into an active phenoxide structure may be used. It can use without being limited to. In the aromatic nucleophilic substitution reaction, water may be generated as a by-product. In this case, regardless of the polymerization solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. As a method for removing water out of the system, a water absorbing material such as molecular sieve can also be used. When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the resulting polymer concentration is 5 to 50% by mass. When the amount is less than 5% by mass, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by mass, the viscosity of the reaction system becomes too high, and the post-treatment of the reaction product tends to be difficult. After completion of the polymerization reaction, the polymer is precipitated as a solid by pouring the reaction solution into a solvent having low polymer solubility, and the polymer can be obtained by filtration of the precipitate. In addition, the solvent is removed from the reaction solution by evaporation. The desired polymer can also be obtained by removing and washing the residue if necessary.

  In addition, the ionic group-containing polymer compound of the present invention can be obtained by, for example, subjecting a polymer compound containing the constituents represented by the general formulas (1) and (3) to a part or all of the cyano group. It can also be obtained by reacting hydrolytically and converting it to a carboxyl group or a derivative thereof. In this reaction, by leaving a part of the cyano group unreacted, the ionic group-containing polymer compound of the present invention can be made into a polymer compound having a structure further containing a cyano group. In this acid treatment, inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and polyphosphoric acid having various concentrations can be used. In consideration of ease of post-treatment, these acids are preferably used as an aqueous solution. As the acid treatment temperature, an appropriate temperature can be selected in order to control the progress of the necessary hydrolysis, but it is preferably set to a temperature of 50 ° C. or higher in order to shorten the reaction time. More preferably, it is 100 degreeC or more. This reaction is preferably performed at 200 ° C. or lower in order to suppress side reactions. The acid concentration can be appropriately selected according to the reaction situation. Considering the solvent treatment after the reaction, it is also preferable to carry out at a concentration of 10 mol / liter or less. Depending on the acid concentration and reaction temperature, the reaction can be performed as a heterogeneous reaction between the polymer solid and the acid solution, or as a homogeneous reaction in which the polymer is dissolved in the acid solution.

  In addition, the ionic group-containing effective molecular compound of the present invention preferably has a polymer log viscosity measured by a method described later of 0.1 or more. When the logarithmic viscosity is less than 0.1, the membrane is likely to be brittle when formed as an ion conductive membrane. The reduced specific viscosity is more preferably 0.3 or more. On the other hand, if the reduced specific viscosity exceeds 5, problems in processability such as difficulty in dissolving the polymer occur, which is not preferable. As a solvent for measuring the logarithmic viscosity, polar organic solvents such as N-methylpyrrolidone and N, N-dimethylacetamide can be generally used. When the solubility in these is low, concentrated sulfuric acid is used. It can also be measured.

  The ionic group-containing polymer compound of the present invention can be used as a simple substance, but can also be used as a resin composition in combination with other polymers. Examples of these polymers include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6, nylon 66, nylon 610, and nylon 12, polymethyl methacrylate, polymethacrylates, and polymethyl. Acrylate resins such as acrylates and polyacrylates, polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate, cellulose such as ethyl cellulose Resin, polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyethers Thermal curing of aromatic polymers such as phon, polyetheretherketone, polyetherimide, polyimide, polyamideimide, polybenzimidazole, polybenzoxazole, polybenzthiazole, epoxy resin, phenol resin, novolac resin, benzoxazine resin There are no particular restrictions on the conductive resin. A resin composition with a basic polymer such as polybenzimidazole or polyvinylpyridine can be said to be a preferable combination for improving the polymer dimensionality, and when a sulfonic acid group is further introduced into these basic polymers, The processability of the composition becomes more preferable. When used as these resin compositions, the ionic group-containing polymer compound of the present invention is preferably contained in an amount of 50% by mass or more and less than 100% by mass of the entire resin composition. More preferably, it is 70 mass% or more and less than 100 mass%. When the content of the ionic group-containing polymer compound of the present invention is less than 50% by mass of the entire resin composition, the ionic group concentration of the ion conductive membrane containing this resin composition is lowered and good ionic conductivity is obtained. The unit containing an ionic group tends to be a discontinuous phase and the mobility of ions to be conducted tends to be reduced. In addition, the composition of the present invention, if necessary, for example, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a viscosity modifier, an antistatic agent, an antibacterial agent, an antifoaming agent, Various additives such as a dispersant and a polymerization inhibitor may be included.

  The ionic group-containing polymer compound of the present invention and the resin composition thereof can be formed into a molded body such as a fiber or a film by any method such as extrusion, spinning, rolling, or casting. Among these, it is preferable to mold from a solution dissolved in an appropriate solvent. Examples of the solvent include aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and hexamethylphosphonamide, and alcohols such as methanol and ethanol. An appropriate one can be selected, but is not limited thereto. A plurality of these solvents may be used as a mixture within a possible range. The compound concentration in the solution is preferably in the range of 0.1 to 50% by mass. If the compound concentration in the solution is less than 0.1% by mass, it tends to be difficult to obtain a good molded product, and if it exceeds 50% by mass, the workability tends to deteriorate. A method of obtaining a molded body from a solution can be performed using a conventionally known method. For example, the molded product can be obtained by removing the solvent by heating, drying under reduced pressure, immersion in a compound non-solvent that can be mixed with a solvent that dissolves the compound, or the like. When the solvent is an organic solvent, the solvent is preferably distilled off by heating or drying under reduced pressure. At this time, it can be formed into various shapes such as a fiber shape, a film shape, a pellet shape, a plate shape, a rod shape, a pipe shape, a ball shape, and a block shape in a composite form with other compounds as necessary. . When combined with a compound having a similar dissolution behavior, it is preferable in that good molding can be achieved. The sulfonic acid group in the molded article thus obtained may contain a salt form with a cationic species, but it can be converted to a free sulfonic acid group by acid treatment as necessary. You can also.

An ion conductive membrane can also be produced from the ionic group-containing polymer compound of the present invention and the resin composition thereof. The most preferable method for forming the ion conductive membrane is casting from a solution, and the ion conductive membrane can be obtained by removing the solvent from the cast solution as described above. Examples of the solution include a solution using an organic solvent such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide, and in some cases, an alcohol solvent. The removal of the solvent is preferably by drying from the uniformity of the ion conductive membrane. Moreover, in order to avoid decomposition | disassembly and alteration of a compound or a solvent, it can also dry at the lowest temperature possible under reduced pressure. Further, when the viscosity of the solution is high, when the substrate or the solution is heated and cast at a high temperature, the viscosity of the solution is lowered and can be easily cast. The thickness of the solution at the time of casting is not particularly limited, but is preferably 10 to 1500 μm. More preferably, it is 50-500 micrometers. If the thickness of the solution is thinner than 10 μm, the form as an ion conductive membrane tends to be not maintained, and if it is thicker than 1500 μm, a non-uniform polymer electrolyte membrane tends to be easily formed. As a method for controlling the cast thickness of the solution, a known method can be used. For example, the amount and concentration of the solution can be cast on a substrate such as a glass plate, a polymer sheet, or a metal plate to a certain thickness using an applicator or doctor blade, or the cast area can be constant using a glass petri dish or the like. The thickness can be controlled. The cast solution can obtain a more uniform film by adjusting the solvent removal rate. For example, in the case of heating, the evaporation rate can be reduced by lowering the temperature in the first stage. In addition, when immersed in a non-solvent such as water, the coagulation rate of the compound can be adjusted by leaving the solution in air or an inert gas for an appropriate time. The ion conductive film of the present invention can have any film thickness depending on the purpose, but it is preferably as thin as possible from the viewpoint of ion conductivity. Specifically, it is preferably 5 to 250 μm, more preferably 5 to 50 μm, and most preferably 5 to 20 μm. If the thickness of the ion conductive membrane is less than 5 μm, handling of the ion conductive membrane becomes difficult and a short circuit or the like tends to occur when a fuel cell is produced. If the thickness is greater than 250 μm, the electric resistance value of the ion conductive membrane increases and the fuel cell The power generation performance tends to decrease. When used as an ion conductive membrane, the sulfonic acid group in the membrane may contain a metal salt, but it can be converted to free sulfonic acid by an appropriate acid treatment. In this case, it is also effective to immerse the membrane in an aqueous solution of sulfuric acid, hydrochloric acid, etc. with or without heating. The ion conductivity of the ion conductive membrane is preferably 1.0 × 10 ⁻³ S / cm or more. When the ion conductivity of 1.0 × 10 ^-3 S / cm or higher, tend to better output is obtained in the fuel cell using the ion conductive membrane, 1.0 × 10 ^-3 S / When it is less than cm, the output of the fuel cell tends to decrease.

The ion conductive membrane of the present invention is also useful for direct methanol fuel cells using methanol as fuel. An ion conductive membrane having a methanol permeation rate of 7 mmol / m ² · sec or less measured at 25 ° C. using a 5 M aqueous methanol solution and having an average thickness of 50 μm is preferable. The methanol permeation rate is more preferably 4 mmol / m ² · sec or less, and more preferably 1 mmol / m ² · sec or less. This is because power generation characteristics particularly excellent when such methanol permeability is exhibited. Methanol permeability evaluation is performed by preparing a sample having an average thickness of 50 μm, but when actually used as an ion conductive membrane for a fuel cell, the thickness is not particularly limited. The film having an average thickness of 50 μm substantially indicates a film having an average thickness in the range of 48 μm to 52 μm.

  Further, by installing the above-described ion conductive membrane or film of the present invention on an electrode, a joined body of the ion conductive membrane or film of the present invention and the electrode can be obtained. As a method for producing this joined body, a conventionally known method can be used. For example, an adhesive is applied to the electrode surface and the ion conductive film and the electrode are bonded, or the ion conductive film and the electrode are bonded. There is a method of heating and pressurizing. Among these, the method of applying and bonding the adhesive mainly composed of the ionic group-containing polymer compound of the present invention and the resin composition to the electrode surface is preferable. This is because it is considered that the adhesion between the ion conductive film and the electrode is improved, and that the ion conductivity of the ion conductive film is less impaired.

  A fuel cell can also be produced using the above-described joined body of an ion conductive membrane or film and an electrode. Since the ion conductive membrane or film of the present invention is excellent in heat resistance, processability, ion conductivity and dimensional stability, it can withstand operation at high temperatures, is easy to produce, and has good output. A fuel cell can be provided. It is also preferable to use it as a fuel cell using methanol as a direct fuel.

EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. Various measurements were performed as follows.
Solution viscosity: The polymer powder was dissolved in N-methylpyrrolidone at a concentration of 0.5 g / dl, the viscosity was measured using an Ubbelohde viscometer in a constant temperature bath at 30 ° C., and the logarithmic viscosity ln [ta / tb] / C) (ta is the drop time of the sample solution, tb is the drop time of the solvent only, and c is the polymer concentration).
IR measurement: Measured by a microscopic method using Biorad FTS-40 as a spectroscope and Biorad UMA-300A as a microscope.

Example 1
3,3′-disulfo-4,4′-dichlorodiphenylsulfone disodium salt (abbreviation: S-DCDPS) 68.44 g (0.1393 mole), 2,6-dichlorobenzonitrile (abbreviation: DCBN) 23.97 g ( 0.1393 mole), 4,4′-biphenol 51.78 g (0.2781 mole) and potassium carbonate 44.20 (0.3198 mole) were weighed into a 1000 ml four-necked flask and flushed with nitrogen. After adding 400 ml of NMP and stirring at 150 ° C. for 1 hour, the reaction was continued by raising the reaction temperature to 195-200 ° C. and sufficiently increasing the viscosity of the system (about 9 hours). After cooling, it was precipitated in strands in water. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the polymer was 1.18.
30 g of the polymer was dissolved in 70 ml of NMP, cast to a thickness of about 350 μm on a heated glass plate, NMP was distilled off until it became a film, and then immersed in water overnight. The obtained film was treated in dilute sulfuric acid at 70 ° C. (concentrated sulfuric acid 6 ml, water 300 ml) for 1 hour to remove the salt, and then left overnight in pure water to remove the acid component. The IR spectrum of the obtained film is shown in FIG.
The obtained film was immersed in 70% polyphosphoric acid, heated to 130 ° C. in an oil bath and treated for 18 hours. The treated film was re-immersed in a 1N aqueous sulfuric acid solution and treated on a 120 ° C. oil bath for 8 hours. The obtained film was washed with water and dried. The IR spectrum of the obtained film is shown in FIG. The absorption of the cyano group at 2234 cm ⁻¹ observed before the treatment disappeared, and the appearance of absorption by hydrolysis of the cyano group was observed at 1689 cm ⁻¹ , confirming the polymer structure of the present invention.
A platinum wire (diameter: 0.2 mm) was pressed against the surface of this film which was formed into a strip shape on a self-made measuring probe (manufactured by Teflon (R)), and a constant temperature / humidity oven at 80 ° C. and 95% RH (Nagano Co., Ltd.) The specimen was held in Science Machine Mfg. Co., Ltd., LH-20-01), and the impedance between the platinum wires was measured by SOLARTRON 1250 FREQUENCY RESPONSE ANALYSER. Proton conductivity (conductivity) measured by changing the distance between the electrodes and canceling the contact resistance between the membrane and the platinum wire according to the following formula from the gradient obtained by plotting the resistance measured values estimated from the distance between the electrodes and the CC plot. [S / cm] = 1 / film width [cm] × film thickness [cm] × resistance interelectrode gradient [Ω / cm]) was calculated to be 0.24 S / cm.

Example 2
A polymer was synthesized in the same manner as in Example 1 except that the molar ratio of S-DCDPS and DCBN was 55:45. The logarithmic viscosity of the obtained polymer was 1.15. The film obtained in the same manner as in Example 1 was immersed in a 70% aqueous sulfuric acid solution and treated on an oil bath at 130 ° C. for 19 hours. The obtained film was washed with water and dried. IR spectra of the film before and after the sulfuric acid treatment are shown in FIGS. The absorption of the cyano group at 2234 cm ⁻¹ observed before the treatment decreased, and the appearance of absorption by hydrolysis of the cyano group was observed at 1685 cm ⁻¹ , confirming the polymer structure of the present invention. The proton conductivity measured in the same manner as in Example 1 was 0.29 S / cm.

Example 3
3,3 ′, 4,4′-tetraaminodiphenylsulfone (abbreviation: TAS) 1.500 g (5.389 × 10 ⁻³ mole), monosodium 2,5-dicarboxybenzenesulfonate (abbreviation: STA, purity 99%) ) 1.445 g (5.389 × 10 ⁻³ mole), 20.48 g of polyphosphoric acid (phosphorus pentoxide content 75%) and 16.41 g of phosphorus pentoxide are weighed in a polymerization vessel. Flow nitrogen and raise the temperature to 100 ° C while stirring gently on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. and polymerized for 4 hours. After completion of the polymerization, the mixture was allowed to cool, and water was added to take out the polymerized product, followed by repeated washing with a home mixer until the pH test paper was neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the polymer was 1.07. 1 g of this polymer and 2 g of the polymer obtained in Example 1 were dissolved in 20 ml of NMP, cast to a thickness of about 350 μm on a heated glass plate, NMP was distilled off until a film was formed, and then immersed in water overnight or longer. . The obtained film was treated in dilute sulfuric acid at 70 ° C. (concentrated sulfuric acid 6 ml, water 300 ml) for 1 hour to remove the salt, and then left overnight in pure water to remove the acid component. The obtained film was immersed in 70% polyphosphoric acid, heated to 130 ° C. in an oil bath and treated for 16 hours. The treated film was re-immersed in a 1N aqueous sulfuric acid solution and treated on a 120 ° C. oil bath for 8 hours. The obtained film was washed with water and dried. In the IR spectrum of the obtained film, the absorption of the cyano group at 2234 cm ⁻¹ observed before the treatment was reduced, and the appearance of absorption by hydrolysis of the cyano group was observed at 1682 cm ⁻¹ . The proton conductivity measured in the same manner as in Example 1 showed a value of 0.10 S / cm.

Example 4
After adding a small amount of ultrapure water and isopropyl alcohol to Pt / Ru catalyst-supported carbon (Tanaka Kikinzoku Kogyo Co., Ltd. TEC61E54) and moistening it, a DuPont 20% Nafion solution (product number: SE-20192) was added to Pt / Ru. The catalyst-supporting carbon and Nafion were added at a weight ratio of 2.5: 1 and stirred to prepare an anode catalyst paste. The catalyst paste was applied and dried by screen printing on carbon paper TGPH-060 manufactured by Toray as a gas diffusion layer so that the amount of platinum deposited was 2 mg / cm ² , thereby producing a carbon paper with an electrode catalyst layer for anode. . Further, after adding a small amount of ultrapure water and isopropyl alcohol to a Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo Co., Ltd. TEC10V40E) and moistening it, a 20% Nafion solution (product number: SE-20192) manufactured by DuPont was added to the Pt catalyst-supporting carbon. A cathode catalyst paste was prepared by adding carbon and Nafion at a weight ratio of 2.5: 1 and stirring. This catalyst paste was applied and dried on a carbon paper TGPH-060 manufactured by Toray made with a water-repellent finish so that the amount of platinum deposited was 1 mg / cm ² , thereby producing a carbon paper with an electrode catalyst layer for cathode. The film produced in Example 1 was sandwiched between the two types of carbon paper with an electrode catalyst layer so that the electrode catalyst layer was in contact with the film sample, and pressurized at 130 ° C. and 8 MPa for 3 minutes by a hot press method. By heating, a membrane-electrode composite was obtained. This joined body was incorporated into an evaluation fuel cell FC25-02SP manufactured by Electrochem, and a power generation test was performed using a fuel cell power generation tester (manufactured by Toyo Corporation). Power generation was performed while supplying a 2 mol / l aqueous methanol solution (1.5 ml / min) and high-purity oxygen gas (80 ml / min) adjusted to 40 ° C. to the anode and the cathode, respectively, at a cell temperature of 40 ° C. Good power generation characteristics of 0.3 V at a current density of 100 mA were obtained.

Example 5
The polymer obtained in Example 1 was dissolved in NMP so as to be 8 wt%, and added so that the weight ratio of Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo Co., Ltd. TEC10V40E) to the polymer was 2.5: 1. The catalyst paste for cathode was prepared by stirring. This catalyst paste was applied and dried on Toray carbon paper TGPH-060 which was subjected to water repellent treatment so that the amount of platinum deposited was 1 mg / cm ² , thereby producing a carbon paper with an electrode catalyst layer. The film obtained in Example 1 was sandwiched between the two obtained carbon papers with an electrode catalyst layer so that the electrode catalyst layer was in contact with the film sample, and the hot press method was performed at 150 ° C. and 8 MPa for 3 minutes. By applying pressure and heating, a membrane-electrode assembly using the polymer as an adhesive was obtained. The electrolyte membrane-electrode assembly is incorporated in an evaluation fuel cell FC25-02SP manufactured by Electrochem, and the cell temperature is 80 ° C., the gas humidification temperature is 80 ° C., the fuel gas is 300 mL / min, the oxidizing gas is 1000 mL / min. When the power generation characteristics were evaluated, a favorable power generation characteristic of 0.6 V at a current density of 500 mA was obtained.

  The ionic group-containing polymer compound of the present invention can provide a polymer electrolyte material that is excellent not only in ion conductivity but also in heat resistance, workability, and dimensional stability. These can be used as ion-conducting membranes in fuel cells and water electrolyzers using hydrogen or methanol as raw materials, and can also be used as various battery electrolytes, display elements, sensors, binders, additives, etc. It can be expected.

It is IR spectrum of the sulfonated polyaryl ether film obtained by S-DCDPS: DCBN = 50: 50. It is IR spectrum after processing the sulfonated polyaryl ether film obtained by S-DCDPS: DCBN = 50: 50 with polyphosphoric acid and sulfuric acid aqueous solution. It is IR spectrum of the sulfonated polyaryl ether film obtained by S-DCDPS: DCBN = 55: 45. It is IR spectrum after processing the sulfonated polyaryl ether film obtained by S-DCDPS: DCBN = 55: 45 with sulfuric acid aqueous solution.

Claims (11)

  An ion conductive polymer compound having a carboxyl group and / or a derivative thereof together with a sulfonic acid group and / or a derivative thereof on an aromatic main chain. The ion conductive polymer compound according to claim 1, comprising structural units represented by general formula (1) and general formula (2).

However, Ar and Ar ′ may be the same or different divalent aromatic groups, X is H or a monovalent cation species, Y is OH, OM (M is a monovalent cation species), NRR ′ (R , R ′ is independently selected from H and an alkyl group.   3. The ion conductive polymer compound according to claim 1, further comprising a cyano group on the aromatic main chain. The ion conductive polymer compound according to claim 3, comprising a structural unit represented by the general formula (3) together with the structural units represented by the general formulas (1) and (2).

  The ion-conductive polymer compound according to any one of claims 1 to 4, wherein the sulfonic acid group content is in the range of 0.3 to 3.5 mg / g.   A composition comprising 50 to 100% by mass of the ion conductive polymer compound according to any one of claims 1 to 5.   An ion conductive membrane comprising the ion conductive polymer compound according to claim 1 and / or the composition according to claim 6.   A composite comprising the ion conductive membrane according to claim 7 and an electrode.   A fuel cell comprising the composite according to claim 8.   An adhesive comprising the ion conductive polymer compound according to claim 1. The manufacturing method which obtains the ion conductive high molecular compound in any one of Claims 1-5 by processing the high molecular compound containing the structural component shown by General formula (1) and (3) with an acidic compound.

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