JP2009064606A - Manufacturing method of polymer electrolyte mold, polymer electrolyte material, polymer electrolyte parts, membrane electrode assembly, and polymer electrolyte fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a polymer electrolyte mold, to provide a polymer electrolyte material, to provide a membrane electrode assembly, and to provide a polymer electrolyte fuel cell achieving high output, high energy density and long-time durability using either of them. <P>SOLUTION: This is the manufacturing method of the polymer electrolyte mold to mold the polymer electrolyte material containing a protection group and an ionizable group, and to deprotect a part of the protection group contained in the obtained mold, and a structural unit containing the protection group is the structural unit represented by the formula. In the formula, Ar<SB>1</SB>and Ar<SB>2</SB>are bivalent arylene groups, A<SB>1</SB>is a bivalent organic group, R<SB>1</SB>is an arbitrary monovalent organic group, A<SB>2</SB>is O or NR<SB>2</SB>(R<SB>2</SB>is a monovalent organic group), and m<SB>1</SB>is 0 or a positive integer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a polymer electrolyte molded body excellent in practicality capable of achieving high output, high energy capacity, and long-term durability, a polymer electrolyte material, a polymer electrolyte component, a membrane electrode composite, and a high The present invention relates to a molecular electrolyte fuel cell.

  BACKGROUND ART A fuel cell is a kind of power generation device that extracts electrical energy by electrochemically oxidizing a fuel such as hydrogen or methanol, and has recently attracted attention as a clean energy supply source. In particular, the polymer electrolyte fuel cell has a low standard operating temperature of around 100 ° C. and a high energy density, so that it is a relatively small-scale distributed power generation facility, a mobile power generator such as an automobile or a ship. As a wide range of applications are expected. It is also attracting attention as a power source for small mobile devices and portable devices, and is expected to be installed in mobile phones and personal computers in place of secondary batteries such as nickel metal hydride batteries and lithium ion batteries.

  In polymer electrolyte fuel cells, in addition to conventional polymer electrolyte fuel cells that use hydrogen gas as fuel (hereinafter referred to as PEFC), direct methanol fuel cells that supply methanol directly (hereinafter referred to as DMFC) It is also noted. Since DMFC is liquid and does not use a reformer, it has the advantage that the energy density is high and the usage time of the portable device per filling is long.

  In a fuel cell, an anode electrode and a cathode electrode in which a reaction responsible for power generation occurs, and a polymer electrolyte membrane serving as a proton conductor between the anode and the cathode are sometimes referred to as a membrane electrode assembly (hereinafter, abbreviated as MEA). ) And a cell in which this MEA is sandwiched between separators is configured as a unit. The polymer electrolyte membrane is mainly composed of a polymer electrolyte material. The polymer electrolyte material is also used as a binder for the electrode catalyst layer.

  The required characteristics of the polymer electrolyte membrane include firstly high proton conductivity. In addition, since the polymer electrolyte membrane functions as a barrier that prevents direct reaction between the fuel and oxygen, low permeability of the fuel is required. In particular, in a polymer electrolyte membrane for DMFC that uses an organic solvent such as methanol as a fuel, methanol permeation is called methanol crossover (hereinafter sometimes abbreviated as MCO), which means a reduction in battery output and energy efficiency. Cause problems. In addition, permeation of hydrogen and oxygen gas becomes a radical generation source, which causes ionomer decomposition. Other required characteristics include chemical stability to withstand a strong oxidizing atmosphere during fuel cell operation and mechanical strength to withstand repeated thinning and swelling and drying.

  Until now, Nafion (registered trademark) (Nafion (registered trademark): manufactured by DuPont), which is a perfluorosulfonic acid polymer, has been widely used for the polymer electrolyte membrane. Nafion (registered trademark) is very expensive because it is manufactured through multi-step synthesis, and there is a problem that fuel crossover is large to form a cluster structure. In addition, due to the lack of hot water resistance and methanol resistance, there is a problem that the mechanical strength of the film made by swelling and drying is lowered, a problem that the softening point is low and the film cannot be used at a high temperature, and a disposal problem and materials after use. There was also a problem that it was difficult to recycle. Perfluorosulfonic acid-based membranes have characteristics that are generally balanced as polymer electrolyte membranes, but further improvements in properties have been required as the batteries are put into practical use.

  In order to overcome such drawbacks, several efforts have already been made on polymer electrolyte materials based on non-perfluoropolymer hydrocarbon polymers. As the polymer skeleton, aromatic polyether ketone and aromatic polyether sulfone have been particularly actively studied from the viewpoint of heat resistance and chemical stability.

  For example, a sulfonated product (for example, non-soluble aromatic polyetheretherketone (Victrex (registered trademark) PEEK (registered trademark) (manufactured by Victrex), etc.)), which is an aromatic polyetherketone, is used. Patent Document 1), a narrowly defined polysulfone that is an aromatic polyethersulfone (hereinafter sometimes abbreviated as PSF) (UDEL P-1700 (manufactured by Amoco) and the like) and a narrowly defined polyethersulfone. (Hereinafter, it may be abbreviated as PES.) Sulfonated products (for example, Non-Patent Document 2) of SUMIKAEXCEL (registered trademark) PES (manufactured by Sumitomo Chemical Co., Ltd.) have been reported. When the content of ionic groups is increased to increase conductivity, the created membrane swells, and fuel crossover such as methanol is large. Cormorants There is a problem, also the mechanical strength of the film produced due to the low cohesive force of polymer molecular chains is disadvantageously insufficient.

  Moreover, in the sulfonated product (for example, Patent Documents 1 and 2) of an aromatic polyether ketone (hereinafter sometimes abbreviated as PEK) (including Victrex PEEK-HT (manufactured by Victrex)). Due to its high crystallinity, a polymer having a low sulfonic acid group density composition is insoluble in a solvent due to residual crystals, resulting in poor processability. Conversely, the sulfonic acid group density is increased to improve processability. When the polymer was not crystalline, it swelled remarkably in water, and not only the fuel crossover of the prepared membrane was large, but also the strength of the prepared membrane was insufficient.

  As a method for controlling the amount of sulfonic acid groups, in aromatic polyether sulfone systems, there have been reports of sulfonated aromatic polyether sulfones in which the amount of sulfonic acid groups is controlled by polymerization using monomers introduced with sulfonic acid groups. (For example, refer to Patent Document 3). However, here too, the problem of swelling of the film prepared under high temperature and high humidity is not improved, and this tendency is particularly remarkable in a fuel aqueous solution such as methanol or in a composition having a high sulfonic acid group density. In addition, it has been difficult for a polymer electrolyte membrane having poor heat resistance and methanol resistance to sufficiently suppress fuel crossover such as methanol and to provide mechanical strength that can withstand a swelling and drying cycle.

  Further, Patent Document 4 describes an aromatic polyether ketone polymer having a ketal group as a protective group. However, the use of the ketal group here is limited to the bisphenol component, and the introduction of the protective group on the aromatic dihalide side is impossible due to the reactivity. Therefore, the main bisphenol component is limited to 4,4′-dihydroxybenzophenone whose ketal group is deprotected, and it is virtually impossible to use a large amount of other highly crystalline bisphenol. Met.

As described above, the polymer electrolyte material according to the prior art is insufficient as a means for improving economy, workability, proton conductivity, fuel crossover, mechanical strength, and long-term durability, and is an industrially useful fuel cell. It could not be a polymer electrolyte material for use.
"Polymer", 1987, vol. 28, 1009. "Journal of Membrane Science", 83 (1993) 211-220. JP-A-6-93114 Japanese translation of PCT publication No. 2004-528683 US Patent Application Publication No. 2002/0091225 JP 2006-261103 A

  In view of the background of such prior art, the present invention is excellent in proton conductivity and excellent in fuel cutoff, mechanical strength, hot water resistance, hot methanol resistance, workability, chemical stability, and polymer electrolyte type Method for producing polymer electrolyte molded body capable of achieving high output, high energy density and long-term durability when used as a fuel cell, and polymer electrolyte material, membrane electrode composite and polymer electrolyte mold using the same We intend to provide a fuel cell.

  In the prior art, the method of introducing sulfonic acid groups onto the aromatic ring by polymer sulfonation reaction (polymer reaction) has the problem that the amount and position of the sulfonic acid groups introduced into the polymer cannot be precisely controlled. Therefore, mass production of polymers and compatibility between crystallinity and processability have been difficult. Therefore, paying attention to the use of protecting groups for the synthesis of polyelectrolyte materials having ionic groups, attempts to mold with protecting groups and the structure, position, introduction amount and electrochemical properties of polymer skeleton and protecting groups The relationship between mechanical properties, dimensional stability, workability, and the like has been studied in detail with a view to fuel cell applications, and the present invention has been completed.

  The present invention employs the following means in order to solve the above problems. That is, as a first means, the method for producing a polymer electrolyte molded body of the present invention is contained in the molded body obtained after molding a polymer electrolyte material containing at least a protective group and an ionic group. A method for producing a polymer electrolyte molded body in which a polymer electrolyte molded body is obtained by deprotecting at least a part of the protective group, wherein the structural unit containing the protective group is represented by the following general formula (P1). The structural unit is characterized by the following.

(In the general formula (P1), Ar ₁ and Ar ₂ are any divalent arylene group, A ₁ is any divalent organic group, R ₁ is any monovalent organic group, A ₂ is O or NR ₂ (R ₂ is an arbitrary monovalent organic group), m ₁ represents 0 or a positive integer. The structural unit represented by the general formula (P1) may be optionally substituted.)
As a second means, the polymer electrolyte material of the present invention is a polymer electrolyte material containing a structural unit represented by (Q2) together with at least the following general formula (Q1), and the general formula (Q1) ) And (Q2), and is composed of an aromatic polyether ketone copolymer containing a total of 50 mol% or more of the structural units represented by (Q2).

(In the general formulas (Q1) and (Q2), Ar _{11 to} Ar ₁₆ are any divalent arylene groups substantially free of ionic groups, A ₁₁ and B ₁₁ are any divalent organic groups, D ₁₁ is a direct bond, O or S, E is O or S, M ¹ and M ² are hydrogen, metal cation or ammonium cation, a1 and a2 are integers of 1 to 4, m _{11 to} m ₁₃ are 0 or positive integers However, the content molar ratio of the structural units represented by the general formulas (Q1) and (Q2) is not 0. The structural units represented by the general formulas (Q1) and (Q2) are other than ionic groups. Optionally substituted with a group.)
The polymer electrolyte component, the membrane electrode assembly, and the polymer electrolyte fuel cell of the present invention are characterized in that they are constructed or manufactured using such a polymer electrolyte material.

  According to the present invention, the proton conductivity is excellent, and the fuel cutoff property, the mechanical strength, the dimensional stability, the workability, and the chemical stability are excellent. A method for producing a polymer electrolyte molded body capable of achieving high energy density and long-term durability, a polymer electrolyte material, a polymer electrolyte membrane component, a membrane electrode assembly, and a polymer electrolyte fuel cell can be provided. .

  Hereinafter, first, the first means of the present invention will be described in detail. The present invention is excellent in the above problems, that is, excellent in proton conductivity, fuel cutoff, mechanical strength, dimensional stability, workability, and chemical stability, and in addition to a polymer electrolyte fuel cell. It can be obtained after earnestly examining the production method of a polymer electrolyte molded body that can achieve output, high energy density, and long-term durability, and molding a polymer electrolyte material containing at least a protective group and an ionic group. A method for producing a polymer electrolyte molded body for obtaining a polymer electrolyte molded body by deprotecting at least a part of the protective group contained in the molded body, wherein the structural unit containing the protective group is: When the production method, which is a structural unit represented by the general formula (P1), was tried, it was found that a polymer electrolyte molded body that can solve such problems at once can be provided.

(In the general formula (P1), Ar ₁ and Ar ₂ are any divalent arylene group, A ₁ is any divalent organic group, R ₁ is any monovalent organic group, A ₂ is O or NR ₂ (R ₂ is an arbitrary monovalent organic group), m ₁ represents 0 or a positive integer. The structural unit represented by the general formula (P1) may be optionally substituted.)
The polymer electrolyte molded body of the present invention includes membranes (including films and films), plates, fibers, hollow fibers, particles, lumps, micropores, coatings, and foams. It can take various forms depending on the intended use. It can be applied to a wide range of applications because it can improve the design flexibility of the polymer and various properties such as mechanical properties and solvent resistance at low cost. It is particularly suitable when the polymer electrolyte molded body is a membrane. Hereinafter, the case of the polymer electrolyte membrane will be described.

  When conventional sulfonated aromatic polyether ketone or sulfonated aromatic polyethersulfone is used as a polymer electrolyte material, the membrane swells when the content of ionic groups is increased to increase proton conductivity, There was a problem that the fuel crossover of methanol or the like was large, and a problem that the mechanical strength of the membrane and the stability of the higher order structure were insufficient due to the low cohesive force of the polymer molecular chain.

  In addition, aromatic polyetherketone (PEK) -based polymers, which are typical examples of crystalline polymers, exhibit crystallinity because of their good packing and extremely strong intermolecular cohesion, and have the property of not dissolving in general solvents at all. . Therefore, in order to obtain a molded body made of the polymer, it has to be melted at an extremely high temperature of 400 ° C. or higher, and it has been difficult to develop into a fuel cell electrolyte material with poor heat resistance or a thin film application. . On the other hand, the polyelectrolyte material containing at least a protective group and an ionic group according to the present invention includes, in particular, PEK polymers that have been difficult to produce in the past by incorporating protective groups in the polymer. By reducing the crystallinity of the crystalline polymer, solubility is imparted so that it can be used in a wide variety of forms including films and membranes and as electrolyte components for fuel cells.

  In addition, after being formed into a film or the like, the molecular chain of the polymer is improved, and at least a part of the protective group is deprotected in order to impart intermolecular cohesion or crystallinity, A polymer electrolyte membrane having significantly improved solvent resistance such as methanol, tensile strength and elongation, mechanical properties such as tear strength and fatigue resistance, and fuel barrier properties such as methanol and hydrogen is obtained. In particular, the polymer electrolyte membrane of the present invention has a high proton conductivity, a film forming property (workability), a low cost and a mass productivity, a dimensional stability, a fuel cutoff property, a mechanical property, It has the feature that both long-term durability can be achieved.

  In the present invention, by protecting and deprotecting the ketone moiety of the PEK-based polymer as a ketimine moiety represented by the general formula (P1), it is possible to design a wide range of molecules while maintaining the polymerization activity. . That is, in the prior art, the use of the ketal group is limited to the bisphenol component in the polymerization reaction, and the main bisphenol component is limited to 4,4′-dihydroxybenzophenone from which the ketal group is deprotected, It was virtually impossible to use a large amount of other highly crystalline bisphenols such as 4,4′-biphenol.

  In addition, the polymer electrolyte membrane obtained by the present invention has a property that is very difficult to break even in a water-containing state due to its strong intermolecular cohesion, that is, has high tear strength, and repeats swelling and drying. Such a polymer electrolyte fuel cell using hydrogen as a fuel for use in automobiles and the like has a feature that it can achieve extremely excellent long-term durability even under operating conditions.

  In addition, it becomes possible to form various crystalline polymers with low sulfonic acid group density, which has not been used so far due to insufficient solubility, and achieves both proton conductivity and fuel crossover suppression effect, The present inventors have succeeded in obtaining the polymer electrolyte membrane of the present invention which is excellent in aqueous property, heat-resistant methanol property, mechanical properties, polymer higher-order structure stability and long-term durability.

  In the present invention, the protecting group is a substituent that is temporarily introduced on the assumption that it is removed at a later stage, protects a highly reactive functional group, and is inert to the subsequent reaction. It can be deprotected after the reaction and returned to the original functional group. That is, it is a pair with a functional group to be protected. For example, a t-butyl group may be used as a protective group for a hydroxyl group, but when the same t-butyl group is introduced into an alkylene chain, It is not called a protecting group. The reaction for introducing a protecting group is called protection (reaction), and the reaction for removal is called deprotection (reaction). In the present invention, the stage for introducing a protecting group may be selected from a monomer stage, an oligomer stage, or a polymer stage, and can be appropriately selected.

  In the present invention, the polymer being crystalline means that the polymer has a crystallizable property that can be crystallized under some conditions. The term “amorphous polymer” means that the polymer is amorphous when used, regardless of whether the polymer is crystalline or not. The presence or absence of crystallinity of these polymers and the crystalline and amorphous states can be evaluated by sharp peaks derived from crystals in wide-angle X-ray diffraction (XRD), crystallization peaks in differential scanning calorimetry (DSC), and the like. .

  Moreover, in this invention, being excellent in hot water resistance and heat-resistant methanol property means that the dimensional change (swelling) in high-temperature water and high-temperature methanol is respectively small. If this dimensional change is large, the membrane may be broken during use as a polymer electrolyte membrane, or it may swell and peel from the electrode catalyst layer, resulting in an increase in resistance. These hot water resistance and hot methanol properties are both important characteristics required for the electrolyte polymer used in the polymer electrolyte fuel cell.

  The protection reaction used in the present invention is a method of protecting / deprotecting a ketone moiety with a ketimine moiety in terms of reactivity, stability, and introduction position. As the structural unit containing a protecting group, the general formula ( It contains the structural unit represented by P1).

  The polymer electrolyte material containing at least a protective group and an ionic group for use in the present invention is more preferably a polymer having an aromatic ring in the main chain among hydrocarbon polymers from the viewpoint of mechanical strength and chemical stability. . That is, it is a polymer having an aromatic ring in the main chain and having an ionic group. The main chain structure is not particularly limited as long as it has an aromatic ring, but preferably has a sufficient mechanical strength to be used, for example, as an engineering plastic.

  Specific examples of the polymer having an aromatic ring in the main chain used in the present invention include polysulfone, polyethersulfone, polyphenylene oxide, polyarylene ether-based polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, polyarylene-based polymer, At least one of components such as polyarylene ketone, polyether ketone, polyarylene phosphine oxide, polyether phosphine oxide, polybenzoxazole, polybenzthiazole, polybenzimidazole, polyamide, polyimide, polyetherimide, polyimidesulfone, etc. The polymer containing is mentioned. 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 the molecular chain thereof. Polyetherketoneketone, polyetheretherketone, It includes polyether ether ketone ketone, polyether ketone ether ketone ketone, polyether ketone sulfone and the like, and does not limit the specific polymer structure.

  Among the polymers having an aromatic ring in the main chain, polysulfone, polyethersulfone, polyphenylene oxide, polyarylene ether-based polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyarylene ketone, polyether ketone, polyarylene phosphine oxide, poly A polymer such as ether phosphine oxide is more preferable from the viewpoint of mechanical strength, processability and hydrolysis resistance.

  Specifically, a polymer containing an aromatic group in the main chain having a repeating unit represented by the following general formula (T1), that is, a polyether polymer or an aromatic polythioether system can be given.

(Here, Z ¹ and Z ² represent an organic group containing an aromatic ring. At least a part of at least one of Z ¹ and Z ² contains an ionic group. Y ¹ represents an electron-withdrawing group. Y ² represents O or S. a and b each independently represent 0 or a positive integer, provided that a and b are not 0 at the same time.)
Among the polymers containing aromatic groups in the main chain having the repeating unit represented by the general formula (T1), the polymers having the repeating units represented by the general formula (T1-1) to the general formula (T1-6) are resistant to It is more preferable in terms of hydrolyzability, mechanical strength and production cost. Among them, from the viewpoint of mechanical strength and production cost, an aromatic polyether polymer in which Y ² is O is more preferable, and most preferably has a repeating unit represented by the general formula (T1-3), that is, Aromatic polyether ketone polymers are most preferred.

(Here, Z ¹ and Z ² represent an organic group containing an aromatic ring. At least a part of at least one of Z ¹ and Z ² contains an ionic group. A and b are each independently 0. Or a positive integer, where a and b are not 0 at the same time.)
Preferred organic groups as Z ¹ are a phenylene group, a naphthylene group, and an anthracenylene group. These may be substituted.

Preferred examples of the organic group represented by R ^p in the general formula (T1-4) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a vinyl group, an allyl group, and a benzyl group. A phenyl group, a naphthyl group, a phenylphenyl group, and the like. From the viewpoint of industrial availability, the most preferable R ^p is a phenyl group.

  In the present invention, the aromatic polyether-based polymer refers to a polymer mainly composed of an aromatic ring and containing an ether bond as a mode in which the aromatic ring units are connected. In addition to the ether bond, there may be a bond mode generally used for forming an aromatic polymer such as a direct bond, ketone, sulfone, sulfide, various alkylenes, imides, amides, esters, and urethanes. The ether bond is preferably at least one per repeating unit of the main constituent component. The aromatic ring may include not only a hydrocarbon aromatic ring but also a hetero ring. Further, a part of the aliphatic units may constitute a polymer together with the aromatic ring unit. Aromatic units include hydrocarbon groups such as alkyl groups, alkoxy groups, aromatic groups, allyloxy groups, halogen groups, nitro groups, cyano groups, amino groups, halogenated alkyl groups, carboxyl groups, phosphonic acid groups, hydroxyl groups, etc. And may have an arbitrary substituent.

  Even when the aromatic polyether polymer contains a bonding mode other than an ether bond such as a direct bond, the position of the protective group to be introduced is the aromatic ether polymer part from the viewpoint of improving processability. Is more preferable.

In the present invention, A ₁ is an arbitrary divalent organic group, and is not particularly limited because it does not have to participate in polymerization. Either an alkylene group or an arylene group can be conveniently selected according to the purpose. Is possible. In the present invention, a divalent arylene group is more preferable from the viewpoint of crystallinity. Specifically, it is the same as Ar ₁ and Ar ₂ described later.

As the m _1, more preferably an integer of 0 to 3 in terms of production cost, and most preferably 0.

Furthermore, as R ₁ and R ₂ in the general formula (P1), any monovalent organic group can be used, and is selected in consideration of the resulting reactivity, stability, polymer solubility, and the like. Is possible. Preferable examples thereof include an alkyl group, a cyclic alkyl group, an alkyl group containing an aromatic ring, an aryl group, and an organic group containing nitrogen. Preferable examples of the alkyl group include a linear alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a hexyl group, and a carbon number of 3 to 3 such as a cyclopentyl group, a cyclohexyl group, and a norbornyl group. 12 cyclic alkyl groups, unsaturated alkyl groups such as vinyl and allyl groups, alkyl groups containing aromatic rings such as benzyl groups, and aryl groups such as phenyl, naphthyl and biphenyl groups, dimethylamino groups, and phenylamino groups Examples of the organic group containing nitrogen such as a group include, but are not limited to, a substituted hydrazone moiety, a carbazone moiety, and an oxime moiety. R ₁ and R ₂ are more preferably linear alkyl groups having 3 to 10 carbon atoms, cyclic alkyl groups having 5 to 10 carbon atoms and aryl groups in terms of raw material cost, solubility, and stability, and are most preferable. Are a phenyl group, a cyclopentyl group, and a cyclohexyl group. These derivatives are also suitable examples.

In addition, preferred organic groups as Ar ₁ and Ar ₂ in the general formula (P1) are a phenylene group, a naphthylene group, an anthracenylene group, or a biphenylene group. These may be optionally substituted. As the aromatic polyether polymer of the present invention, Ar ₁ and Ar ₂ in the general formula (P1) are both phenylene groups and m ₁ is 0, because of solubility and easy availability of raw materials. That is, it is more preferable to contain a structural unit represented by the following general formula (P2), and most preferably Ar ₁ and Ar ₂ are both p-phenylene groups.

(In General Formula (P2), R ₁ represents any monovalent organic group. The structural unit represented by General Formula (P2) may be optionally substituted.)
The method for synthesizing the aromatic polyether polymer used in the present invention is not particularly limited as long as it is a method capable of substantially increasing the molecular weight. For example, the aromatic active dihalide compound and 2 It can be synthesized using an aromatic nucleophilic substitution reaction of a polyhydric phenol compound or an aromatic nucleophilic substitution reaction of a halogenated aromatic phenol compound.

  Specifically, for example, the aromatic polyether polymer containing the structural unit represented by the general formula (P1) is a compound represented by the following general formula (P1-1) as an aromatic active dihalide compound. And can be synthesized by an aromatic nucleophilic substitution reaction with any dihydric phenol compound. The structural unit represented by the general formula (P1) may be derived from either the dihydric phenol compound or the aromatic active dihalide compound, but in consideration of the reactivity of the monomer, the aromatic active dihalide compound Is more preferable. Further, the present invention is characterized in that it can be used not only on the dihydric phenol compound side but also on the aromatic active dihalide compound side by protecting with an electron-withdrawing ketimine moiety. This makes it possible to use monomers having high crystallinity such as 4,4 ′ ′-biphenol which could not be used in the prior art.

(In the general formula (P1), Ar ₁ and Ar ₂ are any divalent arylene group, A ₁ is any divalent organic group, R ₁ is any monovalent organic group, A ₂ is O or NR ₂ (R ₂ is any monovalent organic group), m ₁ is 0 or a positive integer, Z represents Cl or F. The structural unit represented by the general formula (P1) may be optionally substituted. Good.)
Specific examples of particularly preferred aromatic dihalide compounds used in the present invention include compounds represented by the following formulas (r1) to (r14), and derivatives derived from these aromatic dihalide compounds. As the polymer electrolyte material used in the present invention, a material containing a structural unit represented by the general formula (P1) as a part of the monomer compound as in the formulas (r13) to (r14) is also a suitable example. . General formula (However, the polyelectrolyte material of the present invention is not limited to these. In addition, these halogenated aromatic phenol compound types are also suitable. Further, as halogen, F ( (Fluorine) is more preferred.

  Among these aromatic dihalide compounds, the compounds represented by the general formulas (r1) to (r5) are more preferable from the viewpoint of raw material cost and polymerization activity, and more preferably from the general formulas (r1) to ( A compound represented by r3), most preferably a compound represented by formula (r1).

  In the present invention, as a method for protecting a ketone moiety as a ketimine moiety, a method in which a precursor compound having a ketone group is reacted with various amine compounds in the presence of a water absorbing agent such as molecular sieve 3A. For example, it can be produced by reacting a ketone precursor 4,4'-difluorobenzophenone with an amine compound in a solvent such as an aromatic hydrocarbon in the presence of a water absorbing agent such as molecular sieve 3A. An amine compound can be used as the amine compound.

  Preferable specific examples of the amine compound include linear alkylamine compounds having 1 to 12 carbon atoms such as methylamine, ethylamine, propylamine, isopropylamine and hexylamine, cyclopentylamine, cyclohexylamine and norbornylamine. C3-C12 cyclic alkylamine compounds, unsaturated alkylamine compounds such as vinylamine and allylamine, alkylamine compounds containing aromatic rings such as benzylamine, and arylamines such as phenylamine, naphthylamine, and biphenylamine Examples of such compounds are not limited to these. Of these, phenylamine, cyclopentylamine, and cyclohexylamine are particularly preferable from the viewpoint of stability.

  Since water is produced as a by-product with the reaction, it is necessary to remove the water from the system, and it is preferable to use a water absorbing agent such as molecular sieve 3A. In this case, regardless of the reaction solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. Azeotropic agents used to remove reaction water or water introduced during the reaction generally do not substantially interfere with the reaction, co-distill with water and boil between about 25 ° C. and about 250 ° C. Any inert compound. Common azeotropic agents include benzene, toluene, xylene, chlorobenzene, methylene chloride, dichlorobenzene, trichlorobenzene and the like. These azeotropic agents are preferably used also as a reaction solvent. In general, it is desirable to carry out the reaction in an inert atmosphere in the absence of oxygen.

  In order to recover the ketimine compound, a standard isolation method can be used if appropriate care is taken not to make the system acidic. In general, it is possible to recrystallize with a general solvent such as toluene to remove unreacted raw materials and the like.

  In addition, other aromatic active dihalide compounds can be used in combination as long as the solubility of the polymer electrolyte material used in the present invention can be maintained. The aromatic active dihalide compound other than the general formula (P1-1) is not particularly limited as long as the molecular weight can be increased by an aromatic nucleophilic substitution reaction with a divalent phenol compound. Preferred examples thereof include 4,4′-dichlorodiphenyl sulfone, 4,4′-difluorodiphenyl sulfone, 4,4′-dichlorodiphenyl ketone, 4,4′-difluorodiphenyl ketone, and 4,4′-dichloro. Examples thereof include diphenylphenylphosphine oxide, 4,4′-difluorodiphenylphenylphosphine oxide, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile and the like. Among these, 4,4′-dichlorodiphenyl ketone and 4,4′-difluorodiphenyl ketone are more preferable in terms of imparting crystallinity, mechanical strength, heat-resistant methanol property, and fuel crossover suppressing effect, and 4,4 ′ from the viewpoint of polymerization activity. -Difluorodiphenyl ketone is most preferred. These aromatic active dihalide compounds can be used alone, but a plurality of aromatic active dihalide compounds can also be used in combination. In the present invention, it is also preferable to copolymerize a compound having a nitrile group or a trifluoromethyl group as an electron-withdrawing group as long as the effects of the present invention are not hindered.

  As a polyelectrolyte material containing at least a protective group and an ionic group synthesized using dichlorodiphenyl ketone or difluorodiphenyl ketone as an aromatic active dihalide compound, a constituent site represented by the following general formula (P5) is further included. It is included and is preferably used. Moreover, as the polymer electrolyte material obtained in the present invention (hereinafter also including the polymer electrolyte material constituting the polymer electrolyte molded product obtained in the present invention), the ketimine site in the general formula (P1) is removed. A structural unit that is protected and converted to a ketone group. It is a component that imparts intermolecular cohesive strength and crystallinity, and is used as fuel for dimensional stability and mechanical strength at high temperatures in methanol water. The polymer electrolyte fuel cell is preferably used because it is an effective component for a material having high tear strength and excellent resistance to repeated swelling and drying.

(The structural unit represented by the general formula (P5) may be optionally substituted.)
The ionic group in the polymer used as the polymer electrolyte material of the present invention may be introduced by block copolymerization or random copolymerization. It can be appropriately selected depending on the chemical structure of the polymer used and the high crystallinity. Random copolymerization is more preferable when fuel barrier properties and low water content are required, and block copolymerization is more preferably used when proton conductivity and high water content are required.

  The ionic group used in the polymer electrolyte material of the present invention is not particularly limited as long as it is a negatively charged atomic group, but preferably has a proton exchange ability. As such a functional group, a sulfonic acid group, a sulfonimide group, a sulfuric acid group, a phosphonic acid group, a phosphoric acid group, and a carboxylic acid group are preferably used. Here, the sulfonic acid group is a group represented by the following general formula (f1), the sulfonimide group is a group represented by the following general formula (f2) [in the general formula, R represents an arbitrary atomic group. The sulfuric acid group is represented by the following general formula (f3), the phosphonic acid group is represented by the following general formula (f4), and the phosphoric acid group is represented by the following general formula (f5) or (f6). And the carboxylic acid group means a group represented by the following general formula (f7).

Such ionic groups include cases where the functional groups (f1) to (f7) are salts. Examples of the cation forming the salt include an arbitrary metal cation, NR ₄ ⁺ (R is an arbitrary organic group), and the like. In the case of a metal cation, the valence and the like are not particularly limited and can be used. Specific examples of preferable metal ions include Li, Na, K, Rh, Mg, Ca, Sr, Ti, Al, Fe, Pt, Rh, Ru, Ir, and Pd. Among them, Na and K that are inexpensive and can easily be proton-substituted without being adversely affected by solubility are more preferably used as the polymer electrolyte material.

  Two or more kinds of these ionic groups can be contained in the polymer electrolyte material, and may be preferable by combining them. The combination is appropriately determined depending on the structure of the polymer. Among them, it is more preferable to have at least a sulfonic acid group, a sulfonimide group, and a sulfuric acid group from the viewpoint of high proton conductivity, and most preferable to have at least a sulfonic acid group from the viewpoint of hydrolysis resistance.

  Examples of the method for introducing an ionic group into these electrolyte polymers include a method of polymerizing using a monomer having an ionic group and a method of introducing an ionic group by a polymer reaction. A method of polymerizing using a monomer having a group is used. This is because by using a method of polymerizing using a monomer having an ionic group, it is possible to produce a polymer in which the introduction position of the ionic group is controlled and the higher order structure is also controlled.

  As a method of polymerizing using a monomer having an ionic group, a monomer having an ionic group in a repeating unit may be used, and if necessary, an appropriate protecting group may be introduced to perform a deprotecting group after polymerization. . Such a method is described, for example, in Journal of Membrane Science, 197, 2002, p.231-242.

  The method for introducing an ionic group will be described with an example. The introduction of a phosphonic acid group into an aromatic ring can be achieved by the method described in Polymer Preprints, 51, 2002, p. is there. Introduction of a phosphate group into an aromatic ring is possible by, for example, phosphoric esterification of an aromatic polymer having a hydroxyl group. Introduction of a carboxylic acid group into an aromatic ring is possible, for example, by oxidizing an aromatic polymer having an alkyl group or a hydroxyalkyl group. Introduction of a sulfate group into an aromatic ring is possible, for example, by sulfate esterification of an aromatic ring having a hydroxyl group. As a method for sulfonating an aromatic ring, that is, a method for introducing a sulfonic acid group, for example, methods described in JP-A-2-16126 or JP-A-2-208322 are known.

  Specifically, for example, the aromatic ring can be sulfonated by reacting with a sulfonating agent such as chlorosulfonic acid in a solvent such as chloroform, or by reacting in concentrated sulfuric acid or fuming sulfuric acid. The sulfonating agent is not particularly limited as long as it aromatically sulfonates an aromatic ring, and other than the above, sulfur trioxide and the like can be used. When the aromatic ring is sulfonated by this method, the degree of sulfonation can be easily controlled by the amount of the sulfonating agent used, the reaction temperature and the reaction time. Introduction of a sulfonimide group into an aromatic polymer can be achieved, for example, by a method of reacting a sulfonic acid group and a sulfonamide group.

  In the present invention, it is more preferable to use a compound having an ionic acid group introduced as a monomer because the amount, arrangement, and crystallinity of the ionic group can be precisely controlled.

  The molding polymer electrolyte material used in the present invention needs to have an ionic group together with the structural unit represented by the general formula (P1). The structural unit containing the ionic group is not particularly limited as long as proton conductivity and polymerization activity are sufficient, and can be used. Among these, those having a structural unit represented by the following general formula (P3) are more preferable in terms of polymerization activity, mechanical properties, and dimensional stability. It is preferable to use a compound in which an ionic acid group is introduced into an aromatic active dihalide compound as a monomer because the amount of the ionic group can be precisely controlled.

(In the general formula (P3), Ar ₃ and Ar ₄ are any divalent arylene group, B ₁ is any divalent organic group, M ¹ and M ² are hydrogen, a metal cation or an ammonium cation, a1 and a2 Represents an integer of 1 to 4, m ₂ represents 0 or a positive integer, and the structural unit represented by the general formula (P3) may be optionally substituted.)
In the present invention, B ₁ is an arbitrary divalent organic group, and is not particularly limited because it does not have to participate in polymerization. Either an alkylene group or an arylene group can be conveniently selected according to the purpose. Is possible. In the present invention, a divalent arylene group is more preferable from the viewpoint of crystallinity. Specifically, it is the same as Ar ₃ and Ar ₄ described later.

As the m _2, more preferably an integer of 0 to 3 in terms of production cost, and most preferably 0.

A preferable organic group as Ar ₃ and Ar ₄ in the general formula (P3) is a phenylene group, a naphthylene group, an anthracenylene group, or a biphenylene group. These may be optionally substituted. As the aromatic polyether-based polymer of the present invention, Ar ₃ and Ar ₄ in the general formula (P3) are both phenylene groups and m ₂ is 0 because of solubility and availability of raw materials. That is, it is more preferable to contain a structural unit represented by the following general formula (P6), and most preferably Ar ₁ and Ar ₂ are both p-phenylene groups.

(In General Formula (P6), M ¹ and M ² represent hydrogen, metal cation, ammonium cation, a1 and a2 each represent an integer of 1 to 4. The structural unit represented by General Formula (P6) is further optionally substituted. May be.)
Specifically, for example, the aromatic polyether polymer containing the structural unit represented by the general formula (P3) is a compound represented by the following general formula (P3-1) as an aromatic active dihalide compound. And can be synthesized by an aromatic nucleophilic substitution reaction with any dihydric phenol compound. Further, as halogen, F is more preferable from the viewpoint of polymerization activity.

(In general formula (P3-1), Ar ₃ and Ar ₄ are any divalent arylene group, B ₁ is any divalent organic group, M ¹ and M ² are hydrogen, a metal cation or an ammonium cation, a1 and a2 is an integer from 1 to 4, m ₂ is 0 or a positive integer, Y is a structural unit represented by represents Cl or F. formula (P3) may be optionally substituted.)
Preferable examples of the monomer having a sulfonic acid group as an ionic group include 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone together with the compound represented by the general formula (P3-1), 3, 3′-disulfonate-4,4′-difluorodiphenyl sulfone, 3,3′-disulfonate-4,4′-dichlorodiphenyl ketone, 3,3′-disulfonate-4,4′-difluorodiphenyl ketone, 3 , 3′-disulfonate-4,4′-dichlorodiphenylphenylphosphine oxide, 3,3′-disulfonate-4,4′-difluorodiphenylphenylphosphine oxide, and the like.

  In terms of proton conductivity and hydrolysis resistance, a sulfonic acid group is most preferable as an ionic group, but the monomer having an ionic group used in the present invention may have another ionic group. . Among these, 3,3′-disulfonate-4,4′-dichlorodiphenyl ketone and 3,3′-disulfonate-4,4′-difluorodiphenyl ketone are more preferable from the viewpoint of heat resistance methanol resistance and fuel crossover suppression effect. From the viewpoint of polymerization activity, 3,3′-disulfonate-4,4′-difluorodiphenyl ketone is most preferred.

  At least a protective group synthesized using 3,3′-disulfonate-4,4′-dichlorodiphenyl ketone, 3,3′-disulfonate-4,4′-difluorodiphenyl ketone as a monomer having an ionic group; The polymer electrolyte material containing an ionic group further includes a structural unit represented by the general formula (P6), and is preferably used. In addition, the polymer electrolyte material obtained in the present invention has a high crystallinity characteristic of a ketone group, and a component that is more excellent in heat-resistant methanol than a sulfone group, and is used at a high temperature in methanol water used as a fuel. Since it becomes an effective component for the material excellent in dimensional stability and mechanical strength, it is used more preferably. These sulfonic acid groups are preferably salted with a monovalent cationic species during polymerization. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto. These aromatic active dihalide compounds can be used alone, but a plurality of aromatic active dihalide compounds can also be used in combination.

  As the dihydric phenol compound used in the present invention, various dihydric phenol compounds that can be used for the polymerization of an aromatic polyether polymer by an aromatic nucleophilic substitution reaction can be used, and are particularly limited. is not. Moreover, what introduce | transduced the sulfonic acid group into these aromatic dihydroxy compounds can also be used as a monomer.

  The halogenated aromatic hydroxy compound is not particularly limited, but 4-hydroxy-4′-chlorobenzophenone, 4-hydroxy-4′-fluorobenzophenone, 4-hydroxy-4′-chlorodiphenyl sulfone, 4-hydroxy-4′-fluorodiphenylsulfone, 4- (4′-hydroxybiphenyl) (4-chlorophenyl) sulfone, 4- (4′-hydroxybiphenyl) (4-fluorophenyl) sulfone, 4- (4′- Examples thereof include hydroxybiphenyl) (4-chlorophenyl) ketone, 4- (4′-hydroxybiphenyl) (4-fluorophenyl) ketone, and the like. These can be used alone or can be used as a mixture of two or more. Further, in the reaction of the activated dihalogenated aromatic compound and the aromatic dihydroxy compound, these halogenated aromatic hydroxy compounds may be reacted together to synthesize an aromatic polyether compound.

  The dihydric phenol compound used in the present invention further contains a structural unit represented by the following general formula (P5) as a dihydric phenol residue from the viewpoint of crystallinity after deprotection of the protecting group and mechanical properties. Those are more preferred. In the specification of the present invention, the dihydric phenol residue means a structural unit remaining after the corresponding dihydric phenol compound reacts with the aromatic active dihalide.

(In the general formula (P4), E is O or S, Ar ₅ and Ar ₆ are any divalent arylene group, D ₁ is a direct bond, ketone group, O or S, m ₃ is 0 or a positive integer. (The structural unit represented by the general formula (P4) may be optionally substituted.)
In the present invention, D ₁ is at least one selected from a direct bond, a ketone group, O, and S, and more preferably a direct bond, O, S, and more preferably in view of polymerization activity and dimensional stability. It is a direct bond. As the m _3, more preferably an integer of 0 to 3 in terms of production cost, and most preferably 0 or 1. Furthermore, E is O or S, but O is more preferable in terms of cost and oxidation resistance.

In addition, Ar ₅ and Ar ₆ in the general formula (P1) are arbitrary divalent arylene groups, and among them, a phenylene group, a naphthylene group, an anthracenylene group, or a biphenylene group is more preferable from the viewpoint of cost. These may be optionally substituted, but unsubstituted is more preferred in terms of crystallinity.

  Specifically, for example, the aromatic polyether polymer containing the structural unit represented by the general formula (P4) uses a compound represented by the following general formula (P4-1) as a divalent phenol compound. And can be synthesized by an aromatic nucleophilic substitution reaction with an aromatic dihalide.

(In General Formula (P4-1), E is O or S, Ar ₅ and Ar ₆ are any divalent arylene group, D ₁ is a direct bond, ketone group, O or S, and m ₃ is 0 or positive. Represents an integer. The structural unit represented by formula (P4-1) may be optionally substituted.)
Specific examples of the divalent phenol compound represented by the general formula (P4-1) include divalent phenol compounds represented by the following general formulas (Y-1) to (Y-9). Divalent thiol compounds that are heteroatom derivatives of these divalent phenol compounds are also suitable examples. In addition, these dihydric phenol compounds into which sulfonic acid groups are introduced can be used as monomers within a range that does not adversely affect the effects of the present invention, but those having no sulfonic acid groups in terms of crystallinity. Is more preferable.

  Among these, from the viewpoint of the group capable of improving crystallinity and cost, the divalent phenol compounds represented by the general formulas (Y-1) to (Y-5) are more preferable, and (Y-1) to (Y It is a dihydric phenol compound represented by Y-3). Due to the improvement in crystallinity, the obtained polymer electrolyte material can be preferably used because it can exhibit performances excellent in mechanical properties, solvent resistance, fuel cutoff properties, long-term durability, and the like.

(The divalent phenol compound represented by the general formulas (Y-1) to (Y-5) may be optionally substituted, but does not contain an ionic group.

(The divalent phenol compounds represented by the general formulas (Y-6) to (Y-9) may be optionally substituted, but n represents an integer of 1 or more.)
As the polymer electrolyte material of the present invention, it is also preferable to copolymerize a hydrophilic and highly crystalline component together with the hydrophobic and highly crystalline divalent phenol compound represented by (P4-1). . Specific examples thereof include the following formulas (Y-10) to (Y-11), (Y-13) to (Y-15). Of these, divalent phenol compounds represented by (Y-10), (Y-14), and (Y-15) are more preferable in terms of crystallinity and dimensional stability.

  In addition, from the viewpoint of balancing the packing property of the polymer as a molding soluble polymer electrolyte material before molding and imparting moldability with a protecting group, a divalent phenol compound with low crystallinity used in combination with a component with high crystallinity is used. Copolymerization is also possible as long as the effects of the present invention are not impaired. Specific examples thereof include divalent phenol compounds represented by (Y-12) and (Y-16) to (Y-30).

(The dihydric phenol compounds represented by the general formulas (Y-10) to (Y-19) may be optionally substituted, but n and m are integers of 1 or more, and Rp is an arbitrary organic group. To express.)

(The dihydric phenol compounds represented by the general formulas (Y-20) to (Y-30) may be optionally substituted.)
Among these, as the group not containing such a protecting group, at least one selected from general formulas (Y-1) to (Y-4) is more preferable from the viewpoints of dimensional stability, production cost, and crystallinity. More preferably, (Y-1) or (Y-2). When a ketal group is used as a protecting group, the general formula (Y-1) has the same structure as the ketone group after deprotection, and thus can be preferably used because of high regularity and crystallinity. On the other hand, general formula (Y-2) can be preferably used since it has high reactivity and crystallinity.

  In the polymer electrolyte material of the present invention, the content of the structural unit represented by the general formula (P1) is as follows: nuclear magnetic resonance spectrum (NMR), thermogravimetry (TGA), temperature-programmed thermal desorption-mass spectrometry It can be measured by evolved gas analysis by (TPD-MS), pyrolysis gas chromatograph, pyrolysis GC-MS, infrared absorption spectrum (IR), elemental analysis and the like.

  When the amount of the protective group contained in the polymer electrolyte material of the present invention is large, since it has solvent solubility, nuclear magnetic resonance spectrum (NMR) is suitable for quantification of the protective group. However, when the amount of the protecting group is very small and insoluble in the solvent, it may be difficult to accurately quantify by NMR or IR. In such a case, quantification of nitrogen atoms by elemental analysis is a suitable quantification method.

  As the soluble polymer electrolyte material for molding according to the present invention, the content of the structural unit represented by the general formula (P1) is not particularly limited, and is conveniently selected according to the amount and solubility of the ionic group. Is possible. Among them, when calculated as a monomer unit to be used, it is more preferably 5 mol% or more and 50 mol% or less, more preferably 15 mol% or more and 45 mol% or less, most preferably 20 mol% or more, It is 40 mol% or less. If the amount is less than 5 mol%, the solubility may be insufficient. If the amount exceeds 50 mol%, polymerization may be difficult, and mechanical properties and dimensional stability may be insufficient. .

  On the other hand, the polymer electrolyte material obtained in the present invention is preferably 10 mol% or less, more preferably 5 mol% or less, most preferably when solvent resistance and mechanical properties are required. Is 2 mol% or less.

  In the polymer electrolyte membrane obtained by the present invention, it is more preferable that all of the protecting groups are deprotected and returned to the ketone moiety, particularly from the viewpoint of mechanical strength, heat-resistant methanol resistance and fuel crossover suppression effect. However, a portion of the ketone moiety protected with a protecting group may remain within a range that does not adversely affect the hot water resistance, hot methanol resistance, and fuel crossover suppression effect. Here, the fact that all of the ketone moiety protected by the protecting group is deprotected means that the residual amount of the ketone moiety protected by the protecting group by the analysis method is below the measurement limit.

  The molded polymer electrolyte obtained by the present invention has a higher-order structure different from a conventional sulfonated crystalline polymer. By passing through the production method of the present invention, the polymer having crystallinity can be made soluble and a uniform and tough film can be obtained. In addition, a polymer electrolyte membrane having a uniform, tough, excellent fuel barrier property and solvent resistance can be obtained with respect to the composition of a low sulfonic acid group density region, which was conventionally insoluble in a solvent and difficult to form a membrane. .

  Next, the second means of the present invention will be described in detail. The polymer electrolyte material of the present invention is a polymer electrolyte material containing at least structural units represented by the following general formulas (Q1) and (Q2), and is represented by the general formulas (Q1) and (Q2) It consists of an aromatic polyether ketone copolymer containing a total of 50 wt% or more units.

(In the general formulas (Q1) and (Q2), Ar _{11 to} Ar ₁₆ are any divalent arylene groups substantially free of ionic groups, A ₁₁ and B ₁₁ are any divalent organic groups, D ₁₁ is a direct bond, O or S, E is O or S, M ¹ and M ² are hydrogen, metal cation or ammonium cation, a1 and a2 are integers of 1 to 4, m _{11 to} m ₁₃ are 0 or positive integers However, the content molar ratio of the structural units represented by the general formulas (Q1) and (Q2) is not 0. The structural units represented by the general formulas (Q1) and (Q2) are other than ionic groups. Optionally substituted with a group.)
Since the polymer electrolyte material of the present invention has high proton conductivity and high regularity, the polymer molecular chain packing is good and the crystallinity or intermolecular cohesion is high. It is excellent in solvent resistance, tensile strength and elongation, mechanical properties such as tear strength and fatigue resistance, and fuel barrier properties such as methanol and hydrogen. In addition, since the sulfonic acid group has a low electron density due to the influence of the adjacent electron-withdrawing ketone group, it has high chemical stability, that is, radical resistance and oxidation resistance.

  In the polymer electrolyte material of the present invention, the content of the structural units represented by the general formulas (Q1) and (Q2) needs to be 50 wt% or more, more preferably 70 wt% or more, and still more preferably 90 wt%. That's it. When it is less than 50 wt%, crystallinity and durability may be insufficient, which is not preferable. If it is a manufacturing method using the ketimine protecting group of this invention, the polymer electrolyte material whose said content is 100 wt% is also producible.

  Here, even if it is a structure different from the content of the structural units represented by the general formulas (Q1) and (Q2), it is included as long as it satisfies the general formulas (Q1) and (Q2) And

  The polymer electrolyte material of the present invention cannot be produced by conventional techniques such as post-sulphonation of a polymer or direct polymerization using a monomer having a sulfonic acid group. This is because polymers having these structures are highly crystalline and are unnecessary for a solvent and are difficult to polymerize and mold. In addition, when the polymer is post-sulfonated, not only is the sulfonic acid group introduced into the aromatic ring having a high electron density, but it is difficult to control the sulfonation position, so the polymer electrolyte material of the present invention It is impossible to make a polymer with the same structure. That is, the polymer electrolyte material of the present invention can only be realized by molding a molding polymer electrolyte material having both an ionic group and a protecting group and then deprotecting it.

  Among them, as a polymer electrolyte material for molding, it is preferable to provide solubility by protecting the ketone group in the general formula (Q1), and thus, it is represented by the general formulas (Q1) and (Q2). As a structural unit, a highly crystalline component can be introduced into the bisphenol component.

  The structural units represented by the general formulas (Q1) and (Q2) may be further optionally substituted, but those having no ionic group or other substituent have crystallinity, mechanical properties, and durability. More preferable in terms. In the general formulas (Q1) and (Q2), the structural unit represented by the general formula (Q1) is represented by the general formula (Q3), a component having a high effect of improving mechanical strength, solvent resistance and the like due to crystallinity. The structural unit is a component that imparts proton conductivity, and is a particularly preferred structural unit in the present invention.

In the introduction of a sulfonic acid group by a polymer reaction into a conventional crystalline aromatic polyether ketone resin, a sulfonic acid group is preferentially introduced into an aromatic ring having a lower electron density, that is, Ar ₁₅ and Ar _16. In addition, it is impossible to contain a large amount of a structural unit represented by the general formula (Q2) and having no sulfonic acid group in Ar ₁₅ and Ar ₁₆ .

In the present invention, m ₁₁ in the general formula (Q1) is more preferably an integer of 0 to 3 and most preferably 0 in terms of production cost. In addition, a preferable organic group as Ar ₁₁ and Ar ₁₂ in the general formula (Q1) is a phenylene group, a naphthylene group, an anthracenylene group, or a biphenylene group. These may be optionally substituted, but unsubstituted is more preferred. The polymer electrolyte material of the present invention contains a structural unit in which both Ar ₁₁ and Ar ₁₂ in the general formula (P1) are phenylene groups and m ₁ is 0 because of solubility and easy availability of raw materials. More preferably, Ar ₁₁ and Ar ₁₂ are both p-phenylene groups.

Further, in the present invention, the m ₁₂ in the general formula (Q2), more preferably an integer of 0 to 3 in terms of production cost, and most preferably 0. In addition, a preferable organic group as Ar ₁₃ and Ar ₁₄ in the general formula (Q2) is a phenylene group, a naphthylene group, an anthracenylene group, or a biphenylene group. These may be optionally substituted, but unsubstituted is more preferred. The polymer electrolyte material of the present invention contains a structural unit in which Ar ₁₃ and Ar ₁₄ in the general formula (Q2) are both a phenylene group and m ₁₂ is 0 because of solubility and easy availability of raw materials. More preferably, Ar ₁₃ and Ar ₁₄ are both p-phenylene groups.

In the present invention, D ₁₁ is at least one selected from a direct bond, a ketone group, O, and S, and more preferably a direct bond, O, S, and more preferably in view of polymerization activity and dimensional stability. It is a direct bond. As the m _13, more preferably an integer of 0 to 3 in terms of production cost, and most preferably 0 or 1. Furthermore, E is O or S, but O is more preferable in terms of cost and oxidation resistance.

Ar ₁₅ and Ar ₁₆ in the general formulas (Q1) and (Q2) are arbitrary divalent arylene groups, but in terms of cost, phenylene group, naphthylene group, anthracenylene group or biphenylene group is more preferable. preferable. These may be optionally substituted, but unsubstituted is more preferred in terms of crystallinity.

  Preferred examples of the general formulas (Q1) and (Q2) are as described in the structural units represented by the general formulas (P1) to (P4).

  In the polymer electrolyte material of the present invention, the content of the general formula (Q2) is 5 mol% or more and 95 mol% or less, based on the sum of the contents of the general formulas (Q1) and (Q2). It is more preferable that Furthermore, it is preferably 20 mol% or more and 70 mol% or less, and most preferably 25 mol% or more and 50 mol% or less. When the content of the general formula (Q2) is less than 5 mol%, proton conductivity is insufficient, which is not preferable. On the other hand, if it exceeds 95 mol%, the water resistance is insufficient.

  As the polymer electrolyte material containing the structural unit represented by (Q2) together with the general formula (Q1) obtained by the present invention, the structural unit represented by the general formula (Q1) is represented by the following general formula (Q3). More preferably, the structural unit represented by the general formula (Q2) is a structural unit represented by the following general formula (Q4).

(In general formulas (Q3) and (Q4), X is at least one selected from the following general formulas (X-1) to (X-6). In general formula (Q4), M1 and M2 are hydrogen atoms). , A metal cation or an ammonium cation, a1 and a2 each represent an integer of 1 to 4. The structural units represented by the general formulas (Q3) and (Q4) may be optionally substituted with a group other than an ionic group. .)

(The groups represented by the general formulas (X-1) to (X-6) may be optionally substituted with groups other than ionic groups.)
The structural units represented by the general formulas (Q3), (Q4), and (X-1) to (X-6) may be further optionally substituted, but have an ionic group or other substituent. Those not present are more preferable in terms of crystallinity, mechanical properties and durability.

  In the polymer electrolyte material obtained by the present invention, it is more preferable that the main chain skeleton is connected at the para position of the phenylene group and that the position is controlled by introducing a sulfonic acid group at the monomer stage. Since the phenylene group is in the para position and the position of the sulfonic acid group is regular, there is an advantage that crystallinity is improved and mechanical strength and solvent resistance are excellent.

  Among these, structural units represented by the following general formulas (Q5-1) to (Q11-2) can be given as particularly preferred specific examples in terms of crystallinity, durability, dimensional stability, and mechanical properties. . Since these polyelectrolyte materials are insoluble in solvents, they could not be prepared because they were difficult to synthesize or process in the prior art, but in the present invention, a sulfonic acid group and a protecting group are contained at the monomer stage. This makes it possible to produce crystalline polymers whose chemical structures are strictly controlled.

(In the general formula (Q5-1) ~ (Q7-2), M 9 represents a hydrogen, metal cation, an ammonium cation, a naphthalene ring Where may be bonded to the ether group.)

(In the general formula (Q8-1) ~ (Q11-2), M 9 represents hydrogen, a metal cation, an ammonium cation.)
Among these, from the viewpoints of durability and crystallinity, structural units represented by general formulas (Q5-1) to (Q7-2) are more preferable, and most preferable are general formulas (Q5-1) and (Q5-2). ).

The chemical structure of the polymer electrolyte material of the present invention has an S = O absorption of 1,030 to 1,045 cm ⁻¹ , 1,160 to 1,190 cm ⁻¹ , 1,130 to ¹ , C-O-C absorption at 250 cm ^-1, can be confirmed by such C = O absorption of 1,640～1,660Cm ^-1, these composition ratio, neutralization titration or sulfonic acid groups, knowing by elemental analysis Can do. Moreover, the structure can be confirmed from the peak of an aromatic proton of 6.8 to 8.0 ppm, for example, by nuclear magnetic resonance spectrum ( ¹ H-NMR). Further, the position and arrangement of sulfonic acid groups can be confirmed by solution ¹³ C-NMR and solid ¹³ C-NMR.

Although it is often difficult to analyze the contents and arrangement of the general formulas (Q1) to (Q7), use ¹ H-NMR, solution ¹³ C-NMR, and solid ¹³ C-NMR to obtain details such as model samples. The structure can be determined by comparison.

  Polymerization by the aromatic nucleophilic substitution reaction to obtain the aromatic polyether polymer used in the present invention can be obtained by reacting the monomer mixture in the presence of a basic 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. Solvents that can be used include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphontriamide and the like. However, it is not limited to these, and any solvent that can be used as a stable solvent in the aromatic nucleophilic substitution reaction may be used. 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 agent such as molecular sieve can also be used.

  Azeotropic agents used to remove reaction water or water introduced during the reaction generally do not substantially interfere with polymerization, co-distill with water and boil between about 25 ° C and about 250 ° C. Any inert compound. Common azeotropic agents include benzene, toluene, xylene, chlorobenzene, methylene chloride, dichlorobenzene, trichlorobenzene and the like. Of course, it is beneficial to select an azeotropic agent whose boiling point is lower than that of the dipolar solvent used. An azeotropic agent is commonly used, but it is not always necessary when high reaction temperatures are used, such as temperatures above 200 ° C., especially when the inert gas is continuously sparged into the reaction mixture. In general, it is desirable to carry out the reaction in an inert atmosphere and in the absence of oxygen.

  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 weight. When the amount is less than 5% by weight, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by weight, 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 solvent is removed from the reaction solution by evaporation, and the residue is washed as necessary to obtain the desired polymer. In addition, by adding the reaction solution to a solvent having low polymer solubility and high by-product inorganic salt solubility, the inorganic salt is removed, the polymer is precipitated as a solid, and the polymer is obtained by filtering the precipitate. You can also. The recovered polymer is optionally washed with water, alcohol or other solvent and dried. Once the desired molecular weight is obtained, halide or phenoxide end groups can optionally be reacted by introducing a phenoxide or halide end-capping agent that forms a stable end group.

  In the present invention, from the viewpoint of processability, it is necessary to introduce the protective group without deprotecting it until the film-forming stage. Therefore, polymerization and purification are performed in consideration of the conditions under which the protective group can exist stably. There is a need. For example, when a ketimine moiety is used as a protecting group, the deprotection reaction proceeds under acidic conditions, so the system must be kept neutral or alkaline.

  In the present invention, the method for deprotecting at least a part of the ketone moiety protected by the ketimine moiety to form a ketone moiety is not particularly limited. The deprotection reaction can be performed in the presence of water and acid under non-uniform or uniform conditions, but from the viewpoint of mechanical strength and solvent resistance, a method of acid treatment after molding into a film or the like Is more preferable. Specifically, it is possible to deprotect the molded membrane by immersing it in an aqueous hydrochloric acid solution, and the acid concentration and the aqueous solution temperature can be appropriately selected.

  The weight ratio of the acidic aqueous solution required for the polymer is preferably 1 to 100 times, but a larger amount of water can be used. The acid catalyst is preferably used at a concentration of 0.1 to 50% by weight of water present. Suitable acid catalysts include strong mineral acids such as hydrochloric acid, nitric acid, fluorosulfonic acid, sulfuric acid, and strong organic acids such as p-toluenesulfonic acid, trifluoromethane sulfonic acid, and the like. Depending on the film thickness of the polymer and the like, the amount of acid catalyst and excess water, reaction pressure, and the like can be selected as appropriate.

  For example, if it is a film with a thickness of 50 μm, it can be easily deprotected by immersing it in an acidic aqueous solution as exemplified by a 6N hydrochloric acid aqueous solution and heating at 95 ° C. for 1 to 48 hours. It is. Further, even when immersed in a 1N aqueous hydrochloric acid solution at 25 ° C. for 24 hours, most of the protecting groups can be deprotected. However, the deprotection conditions are not limited to these, and the deprotection may be performed with an acid gas, an organic acid, or the like, or may be deprotected by heat treatment.

  The molecular weight of the polymer used as the polymer electrolyte material containing at least a protective group and an ionic group of the present invention thus obtained is a polystyrene-equivalent weight average molecular weight of 10,000 to 5,000,000, preferably 10,000 to 500,000. If it is less than 10,000, the mechanical strength may be insufficient, such as cracking in the molded film. On the other hand, if it exceeds 5 million, there may be problems such as insufficient solubility, high solution viscosity, and poor processability. In addition, since the polymer electrolyte material obtained by the present invention is insoluble in a solvent, it may be difficult to measure the molecular weight.

  The polymer electrolyte material of the present invention preferably has a crystallinity of less than 0.5% as measured by wide angle X-ray diffraction (XRD).

  The polymer electrolyte material containing at least a protective group and an ionic group used in the present invention is more preferably amorphous from the viewpoint of a soluble polymer electrolyte material for molding that requires workability. It is preferable that it is less than%. When the degree of crystallinity is 0.5% or more, workability is insufficient and a uniform and tough electrolyte membrane may not be obtained. Moreover, since the polymer electrolyte molded body obtained by the present invention is also affected by the crystallinity of the soluble polymer electrolyte material for molding, the crystallinity is more preferably less than 0.5%. When the crystallinity is 0.5% or more, the toughness is insufficient and the long-term durability may be insufficient, which is not preferable.

  The polymer electrolyte material obtained in the present invention is excellent in solvent resistance from the viewpoint of fuel barrier properties and high energy capacity by using a high concentration fuel, that is, after being immersed in N-methylpyrrolidone at 100 ° C. for 2 hours. More preferably, the weight loss is 70% by weight or less. Alcohols such as methanol are often used as the liquid fuel. In the present invention, the solvent resistance is evaluated using N-methylpyrrolidone having excellent solubility regardless of the polymer type. More preferably, it is 50 weight% or less, Most preferably, it is 30 weight% or less. When the weight loss exceeds 70% by weight, not only the fuel barrier property but also the crystallinity is insufficient, resulting in insufficient mechanical strength and long-term durability, or for DMFC using high-temperature and high-concentration methanol aqueous solution as fuel When used in the above, it is not preferable because the film dissolves or swells greatly. In addition, it becomes difficult to apply a catalyst paste directly to the polymer electrolyte membrane to produce a membrane electrode assembly, which not only increases the manufacturing cost but also increases the interfacial resistance with the catalyst layer, resulting in sufficient power generation. Characteristics may not be obtained.

  When the polymer electrolyte material of the present invention is used for a fuel cell, it is usually used in a membrane state and a binder for a catalyst layer.

  There is no particular limitation on the method of molding the polymer electrolyte material containing at least a protecting group and an ionic group into a polymer electrolyte membrane according to the present invention. A method or a method of forming a film from a molten state is possible. In the former, for example, the polymer electrolyte material is dissolved in a solvent such as N-methyl-2-pyrrolidone, the solution is cast on a glass plate or the like, and the solvent is removed to form a film. It can be illustrated.

  The solvent used for film formation is not particularly limited as long as it can dissolve the aromatic polyether polymer and then remove it. For example, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl- Aprotic polar solvents such as 2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphontriamide, ester solvents such as γ-butyrolactone, butyl acetate, ethylene carbonate, propylene carbonate Carbonate solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and other alkylene glycol monoalkyl ethers, or isopropanol Alcohol solvents such as Le, water and mixtures thereof is preferably used, is preferred for high highest solubility aprotic polar solvent.

  It is a preferable method to obtain a tough membrane by subjecting the polymer solution prepared to a required solid content concentration to normal pressure filtration or pressure filtration to remove foreign substances present in the polymer electrolyte solution. The filter medium used here is not particularly limited, but a glass filter or a metallic filter is suitable. In the filtration, the pore size of the minimum filter through which the polymer solution passes is preferably 1 μm or less. If filtration is not carried out, foreign matter is allowed to enter, and film breakage occurs or durability becomes insufficient.

  Next, the polymer electrolyte membrane obtained in the present invention is preferably heat-treated in the state of a metal salt at least part of the ionic groups. If the polymer electrolyte material to be used is polymerized in the form of a metal salt at the time of polymerization, it is preferable to perform film formation and heat treatment as it is. The metal of the metal salt is not limited as long as it can form a salt with sulfonic acid, but Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, W, and the like are preferable. Among these, Li, Na, K, Ca, Sr, and Ba are more preferable, and Li, Na, and K are more preferable. The temperature of this heat treatment is preferably 150 to 550 ° C, more preferably 160 to 400 ° C, and particularly preferably 180 to 350 ° C. The heat treatment time is preferably 10 seconds to 12 hours, more preferably 30 seconds to 6 hours, and particularly preferably 1 minute to 1 hour. If the heat treatment temperature is too low, the fuel permeability suppressing effect, elastic modulus, and breaking strength are insufficient. On the other hand, if it is too high, the film material tends to deteriorate. If the heat treatment time is less than 10 seconds, the heat treatment effect is insufficient. On the other hand, when it exceeds 12 hours, the film material tends to deteriorate. The polymer electrolyte membrane obtained by the heat treatment can be proton-substituted by being immersed in an acidic aqueous solution as necessary. By molding by this method, the polymer electrolyte membrane of the present invention can achieve both a good balance between proton conductivity and fuel barrier properties, mechanical properties, long-term durability, and solvent resistance.

  As a method of converting the polymer electrolyte material used in the present invention into a polymer electrolyte membrane, a membrane composed of the aromatic polyether-based polymer is prepared by the above method, and then the ketone moiety protected with a ketimine moiety is used. At least a part is deprotected to form a ketone moiety. This method makes it possible to form a solution of a low sulfonic acid group polymer with poor solubility, achieving both proton conductivity and a fuel crossover suppression effect, excellent solvent resistance, mechanical properties, and dimensional stability. It becomes possible.

  In the present invention, a method of deprotecting a ketone moiety protected by a ketimine moiety to form a ketone moiety is not particularly limited, and examples thereof include a method of acid treatment after molding. Specifically, it is possible to deprotect the molded membrane by immersing it in an aqueous hydrochloric acid or sulfuric acid solution. The acid concentration and aqueous solution temperature take into account the ease of soaking into the molded product. It can be selected appropriately. For example, if the film has a thickness of 50 μm, it can be easily deprotected by dipping in an acidic aqueous solution as exemplified by a 6N hydrochloric acid aqueous solution and heating at 95 ° C. for 8 hours. However, the deprotection conditions are not limited to these, and the deprotection may be performed with an acid gas or an organic acid.

  The polymer electrolyte membrane obtained by the present invention can further have a polymer structure crosslinked by means such as radiation irradiation, if necessary. By crosslinking such a polymer electrolyte membrane, an effect of further suppressing fuel crossover and swelling with respect to the fuel can be expected, and the mechanical strength may be improved, which may be more preferable. Examples of such radiation irradiation include electron beam irradiation and γ-ray irradiation.

  The thickness of the polymer electrolyte membrane obtained by the present invention is preferably 1 to 2000 μm. A thickness of more than 1 μm is more preferable for obtaining the strength of a film that can withstand practical use, and a thickness of less than 2000 μm is preferable for reducing film resistance, that is, improving power generation performance. A more preferable range of the film thickness is 3 to 500 μm, and a particularly preferable range is 5 to 250 μm. The film thickness can be controlled by the solution concentration or the coating thickness on the substrate.

  In addition, the polymer electrolyte membrane obtained by the present invention contains additives such as crystallization nucleating agents, plasticizers, stabilizers, antioxidants or mold release agents used in ordinary polymer compounds. It can be added within a range not contrary to the purpose. Moreover, you may reinforce with a microporous film, a nonwoven fabric, a mesh, etc.

  In addition, the polymer electrolyte membrane obtained by the present invention has various polymers, elastomers, and the like for the purpose of improving mechanical strength, thermal stability, workability, etc. within a range that does not adversely affect the above-mentioned various properties. Fillers, fine particles, various additives, and the like may be included.

The polymer electrolyte membrane of the present invention preferably has a methanol permeation amount per unit area of 40 μmol · min ⁻¹ · cm ⁻² or less with respect to a 30 wt% aqueous methanol solution under the condition of 20 ° C. In the fuel cell using the polymer electrolyte membrane, from the viewpoint of obtaining high output and high energy capacity in a region where the fuel concentration is high, it is desired that the fuel permeation amount is small in order to maintain a high fuel concentration. is there. The amount of methanol permeated is measured after the polymer electrolyte membrane is immersed in pure water at 25 ° C. for 24 hours.

From this viewpoint, 0 μmol · min ⁻¹ · cm ⁻² is most preferable, but from the viewpoint of ensuring proton conductivity, 0.01 μmol · min ⁻¹ · cm ⁻² or more is preferable.

In addition, the polymer electrolyte membrane obtained by the present invention preferably has a proton conductivity per unit area of 1 S · cm ⁻² or more, and more preferably ² S · cm ⁻² or more. Proton conductivity can be measured by the constant potential alternating current impedance method, which is performed as quickly as possible after immersing the polymer electrolyte membrane in pure water at 25 ° C. for 24 hours, taking it out in an atmosphere of 25 ° C. and 50% to 80% relative humidity. it can.

By setting the proton conductivity per unit area to 1 S · cm ⁻² or more, when used as a polymer electrolyte membrane for a fuel cell, sufficient proton conductivity, that is, sufficient battery output can be obtained. Higher proton conductivity is preferable, but a membrane with high proton conductivity is likely to be dissolved or disintegrated by a fuel such as methanol water, and the fuel permeation amount tends to increase, so a practical upper limit is 50 S · cm. ^-2 .

  The polymer electrolyte membrane obtained by the present invention preferably achieves the low methanol permeation amount and the high proton conductivity as described above from the viewpoint of achieving both high output and high energy capacity.

  The polymer electrolyte component in the present invention means a component containing a polymer electrolyte molded body and a polymer electrolyte material. In the present invention, the shape of the polymer electrolyte component is the same as that of the aforementioned polymer electrolyte molded body.

  In the present invention, the polymer electrolyte molded body means a molded body containing the polymer electrolyte material of the present invention. In the present invention, specific shapes of the molded body include, in addition to membranes (including films and films), plates, fibers, hollow fibers, particles, lumps, microporous, coatings, It can take various forms depending on the intended use, such as foams. Since various properties such as mechanical properties and solvent resistance are excellent, it can be applied to a wide range of applications.

  When the polymer electrolyte material obtained by the present invention is used for a fuel cell, a polymer electrolyte membrane and an electrode catalyst layer are suitable. Among them, it is preferably used for a polymer electrolyte membrane. This is because when used for a fuel cell, it is usually used as a polymer electrolyte membrane or an electrode catalyst layer binder in a membrane state.

  The polymer electrolyte material of the present invention is suitably used for a polymer electrolyte molded body. The polymer electrolyte molded body of the present invention means a molded body containing the polymer electrolyte material of the present invention. In the present invention, specific shapes of the molded body include, in addition to membranes (including films and films), plates, fibers, hollow fibers, particles, lumps, microporous, coatings, It can take various forms depending on the intended use, such as foams. Since various properties such as mechanical properties and solvent resistance can be improved, it can be applied to a wide range of applications.

  When the polymer electrolyte material obtained by the present invention is used for a fuel cell, a polymer electrolyte membrane and an electrode catalyst layer are suitable. Among them, it is preferably used for a polymer electrolyte membrane. This is because when used for a fuel cell, it is usually used as a polymer electrolyte membrane or an electrode catalyst layer binder in a membrane state.

The polymer electrolyte membrane of the present invention can be applied to various uses. For example, extracorporeal circulation column, medical use such as artificial skin, filtration use, ion exchange resin use such as chlorine-resistant reverse osmosis membrane, various structural materials use, electrochemical use, humidification membrane, anti-fogging membrane, antistatic membrane, Applicable to solar cell membranes and gas barrier materials. It is also suitable as an artificial muscle and actuator material. Among these, it can be preferably used for various electrochemical applications. Examples of the electrochemical application include a fuel cell, a redox flow battery, a water electrolysis device, a chloroalkali electrolysis device, and the like, among which the fuel cell is most preferable.
Further, among fuel cells, it is suitable for a polymer electrolyte fuel cell, and there are those using hydrogen as a fuel and those using an organic compound such as methanol as a fuel. It is particularly preferably used for a direct fuel cell using at least one selected from a mixture of water and water as fuel. As the organic compound having 1 to 6 carbon atoms, alcohols having 1 to 3 carbon atoms such as methanol, ethanol and isopropyl alcohol, and dimethyl ether are preferable, and methanol is most preferably used.

  The membrane electrode composite of the present invention means a membrane electrode composite containing the polymer electrolyte material of the present invention in a polymer electrolyte membrane or a catalyst layer. Furthermore, the membrane electrode composite is a component in which a polymer electrolyte membrane and an electrode are combined.

  There is no particular limitation on the method of joining the polymer electrolyte membrane and the electrode when using such a polymer electrolyte membrane as a fuel cell, and a known method (for example, a chemical plating method described in Electrochemistry, 1985, 53, p.269. , Applied Electrochemical Society (J. Electrochem. Soc.), Electrochemical Science and Technology, 1988, 135, 9, p.2209. Is possible.

  Among the fuel cells, it is suitable for a polymer electrolyte fuel cell, and there are those using hydrogen as a fuel and those using an organic compound such as methanol as a fuel. It is particularly preferably used for a direct fuel cell using at least one selected from a mixture of water as fuel. As the organic compound having 1 to 6 carbon atoms, alcohols having 1 to 3 carbon atoms such as methanol, ethanol and isopropyl alcohol, and dimethyl ether are preferable, and methanol is most preferably used.

  Fuels for fuel cells using the membrane electrode assembly of the present invention include oxygen, hydrogen and methane, ethane, propane, butane, methanol, isopropyl alcohol, acetone, glycerin, ethylene glycol, formic acid, acetic acid, dimethyl ether, hydroquinone, cyclohexane Examples thereof include organic compounds having 1 to 6 carbon atoms and mixtures of these with water, and may be one kind or a mixture of two or more kinds. In particular, a fuel containing hydrogen and an organic compound having 1 to 6 carbon atoms is preferably used from the viewpoint of power generation efficiency and simplification of the entire battery system, and hydrogen and aqueous methanol are particularly preferable in terms of power generation efficiency.

  In the case of using an aqueous methanol solution, the concentration of methanol is appropriately selected depending on the fuel cell system to be used, but a concentration as high as possible is preferable from the viewpoint of long-time driving. For example, an active fuel cell having a system for sending a medium necessary for power generation, such as a liquid feed pump or a blower fan, to a membrane electrode assembly, or an auxiliary machine such as a cooling fan, a fuel dilution system, or a product recovery system has a methanol concentration of 30. It is preferable to inject ~ 100% or more of fuel with a fuel tank or fuel cassette, dilute it to about 0.5 to 20%, and send it to the membrane electrode assembly. Is preferable in the range of 10 to 100%.

  Furthermore, the application of the polymer electrolyte fuel cell using the polymer electrolyte material of the present invention is not particularly limited, but a power supply source for a moving body is preferable. In particular, mobile devices such as mobile phones, personal computers, PDAs, televisions, radios, music players, game machines, headsets, DVD players, human-type and animal-type robots for industrial use, home appliances such as cordless vacuum cleaners, and toys , Electric bicycles, motorcycles, automobiles, buses, trucks and other vehicles and ships, power supplies for mobiles such as railways, stationary primary generators such as stationary generators, or alternatives to these It is preferably used as a hybrid power source.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. In addition, the measurement conditions of each physical property are as follows. Further, a chemical structural formula is inserted in this example, and the chemical structural formula is inserted for the purpose of helping the reader to understand. The chemical structure of the polymerization component of the polymer, the exact composition, the arrangement, the sulfonic acid The position, number, molecular weight, and the like of the group are not necessarily expressed accurately, and are not limited thereto.

(1) Density of sulfonic acid group A sample of a membrane serving as a specimen was immersed in pure water at 25 ° C. for 24 hours, vacuum-dried at 40 ° C. for 24 hours, and then measured by elemental analysis. Carbon, hydrogen, and nitrogen were analyzed by a fully automatic elemental analyzer varioEL, sulfur was analyzed by a flask combustion method / barium acetate titration, and fluorine was analyzed by a flask combustion / ion chromatograph method. The sulfonic acid group density per unit gram (mmol / g) was calculated from the composition ratio of the polymer.

(2) Proton conductivity After immersing the membrane-like sample in pure water at 25 ° C. for 24 hours, the membrane sample is kept in a constant temperature and humidity chamber at 80 ° C. and 95% relative humidity for 30 minutes. The degree was measured.

  As a measuring apparatus, a Solartron electrochemical measurement system (Solartron 1287 Electrochemical Interface and Solartron 1255B Frequency Response Analyzer) was used, and constant potential impedance measurement was performed by a two-terminal method to determine proton conductivity. The AC amplitude was 50 mV. A sample having a width of 10 mm and a length of 50 mm was used. The measurement jig was made of phenol resin, and the measurement part was opened. As an electrode, a platinum plate (thickness: 100 μm, 2 sheets) was used. The electrodes were disposed at a distance of 15 mm between the electrodes, on the front side and the back side of the sample membrane, in parallel with each other and perpendicular to the longitudinal direction of the sample membrane.

(3) Weight average molecular weight The weight average molecular weight of the polymer was measured by GPC. Tosoh's HLC-8022GPC is used as an integrated device of an ultraviolet detector and a differential refractometer, and Tosoh's TSK gel SuperHM-H (inner diameter 6.0 mm, length 15 cm) is used as the GPC column. N-methyl-2 -Measured with a pyrrolidone solvent (N-methyl-2-pyrrolidone solvent containing 10 mmol / L of lithium bromide) at a flow rate of 0.2 mL / min, and the weight average molecular weight was determined in terms of standard polystyrene.

(4) Measurement of dimensional change rate The dimensional stability (dimensional change rate) of the electrolyte membrane was evaluated by measuring the dimensional change rate against hot water at 80 ° C. The electrolyte membrane was cut into a strip having a length of about 5 cm and a width of about 1 cm, and immersed in water at 25 ° C. for 24 hours. The electrolyte membrane was immersed in hot water at 80 ° C. for 2 hours, and then the length (L1) was measured with a caliper. Further, after vacuum drying at 80 ° C. for 16 hours, the length (L2) was measured again with a caliper, and the dimensional change rate (= L1 / L2 × 100, unit%) was obtained.

(5) Film thickness It measured using Mitutoyo ID-C112 type | mold set to Mitutoyo granite comparator stand BSG-20.

(6) Nuclear magnetic resonance spectrum (NMR)
Under the following measurement conditions, ¹ H-NMR was measured to confirm the structure.

Apparatus: EX-270 manufactured by JEOL Ltd.
Resonance frequency: 270 MHz ( ¹ H-NMR)
Measurement temperature: room temperature Dissolving solvent: DMSO-d6 or CDCl ₃
Internal reference material: TMS (0 ppm)
Integration count: 16 times Synthesis example 1
4,4′-difluoro (N-benzohydroxylidene aniline) represented by the following general formula (G1) was synthesized.

262 g (Aldrich reagent) of 4,4′-difluorobenzophenone and 124 g of aniline (Aldrich reagent) were reacted for 24 hours while refluxing in 1.8 L of toluene in the presence of 1.8 kg of molecular sieve 3A. After cooling to 25 ° C., the molecular sieve was removed by filtration. The obtained solution was concentrated by an evaporator and then recrystallized by cooling in an ice bath. The obtained crystals were filtered, vacuum dried at 80 ° C., and recrystallized again with toluene to obtain 207 g of 4,4′-difluoro (N-benzohydroxylidene aniline). The purity was 99.8%. The structure was confirmed by ¹ H-NMR. Impurities were quantitatively analyzed by liquid chromatography.

Synthesis example 2
Disodium 3,3′-disulfonate-4,4′-difluorobenzophenone represented by the following general formula (G2) was synthesized.

109.1 g (Aldrich reagent) of 4,4′-difluorobenzophenone was reacted at 150 ° C. for 10 hours in 150 mL of fuming sulfuric acid (50 wt% SO ₃ ) (Wako Pure Chemicals reagent). Thereafter, the mixture was poured little by little into a large amount of water, neutralized with NaOH, and 200 g of sodium chloride was added to precipitate the composite. The resulting precipitate was filtered off and recrystallized with an aqueous ethanol solution to obtain disodium 3,3′-disulfonate-4,4′-difluorobenzophenone represented by the above general formula (G2). The purity was 99.3%. The structure was confirmed by ¹ H-NMR. Impurities were quantitatively analyzed by capillary electrophoresis (organic matter) and ion chromatography (inorganic matter).

Synthesis example 3
4,4′-difluoro (N-benzohydroxylidene cyclohexylamine) was synthesized by the method described in Synthesis Example 1 except that 124 g of aniline (Aldrich reagent) was changed to 131 g of cyclohexylamine (Aldrich reagent).

Example 1
A polymer represented by the following general formula (G3) was synthesized.

  In a 500 mL three-necked flask equipped with a stirrer, a nitrogen introduction tube, and a Dean-Stark trap, 6.9 g of potassium carbonate, 7.5 g of 4,4′-biphenol (Tokyo Kasei Reagent), 4,4 obtained in Synthesis Example 1 above. 7.0 g of '-difluoro (N-benzohydroxylidene aniline) and 6.8 g of disodium 3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2 were added. -After dehydration at 180 ° C in 50 mL of methylpyrrolidone (NMP) and 30 mL of toluene, the temperature was raised to remove toluene, and polymerization was carried out at 24 ° C for 12 hours. Purification was performed by reprecipitation with a large amount of water to obtain a soluble polymer electrolyte material for molding represented by the above formula (G3). The weight average molecular weight was 180,000.

  The obtained 25 wt% N-methylpyrrolidone (NMP) solution in which the soluble polymer electrolyte material for molding of the formula (G3) was dissolved was subjected to pressure filtration using a glass fiber filter, and then cast onto a glass substrate. After drying at 100 ° C. for 4 hours, the temperature was raised to 300 ° C. over 30 minutes under nitrogen and heat treated at 300 ° C. for 10 minutes to obtain a film. The solubility of the polymer was very good. After immersing in 9N hydrochloric acid for 24 hours at 995 ° C. for proton substitution and deprotection reaction, it was immersed in a large excess amount of pure water for 24 hours and thoroughly washed to obtain a polymer electrolyte membrane. The resulting membrane had a sulfonic acid group density of 1.9 mmol / g.

The obtained membrane had a thickness of 31 μm and proton conductivity of 87 mS / cm. The dimensional change rate was 13%, the conductivity was high, and the dimensional stability was excellent. Even when immersed in NMP at 100 ° C., it did not dissolve. Moreover, even if it was bent, twisted, or stretched approximately twice, it was not torn and was a high strength and high toughness film. In the infrared absorption spectrum (IR), the peak at 1592 cm ⁻¹ disappeared, and the presence of an imine group was not observed.

Example 2
8.2 g of 4,4′-difluoro (N-benzohydroxylidene aniline) obtained in Synthesis Example 1 and disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 The polymer was polymerized and the film was prepared by the method described in Example 1 except that was changed to 5.1 g. The weight average molecular weight was 240,000. The resulting membrane had a sulfonic acid group density of 1.5 mmol / g.

The obtained membrane had a thickness of 30 μm and a proton conductivity of 46 S / cm. Moreover, the dimensional change rate was 7%, and the dimensional stability was excellent. Even when immersed in NMP at 100 ° C., it did not dissolve. Moreover, even if it was bent, twisted, or stretched approximately twice, it was not torn and was a high strength and high toughness film. In the infrared absorption spectrum (IR), the peak at 1592 cm ⁻¹ disappeared, and the presence of an imine group was not observed.

Example 3
The 4,4′-difluoro (N-benzohydroxylidene aniline) obtained in Synthesis Example 1 was changed to 7.2 g of 4,4′-difluoro (N-benzohydroxylidene cyclohexylamine) obtained in Synthesis Example 3. Except for the above, polymerization of the polymer and production of the film were carried out by the methods described in Example 1. The weight average molecular weight was 200,000. The resulting membrane had a sulfonic acid group density of 1.9 mmol / g.

The obtained membrane had a thickness of 31 μm and a proton conductivity of 91 mS / cm. The dimensional change rate was 14%, the conductivity was high, and the dimensional stability was excellent. Even when immersed in NMP at 100 ° C., it did not dissolve. Moreover, even if it was bent, twisted, or stretched approximately twice, it was not torn and was a high strength and high toughness film. In the infrared absorption spectrum (IR), the peak at 1592 cm ⁻¹ disappeared, and the presence of an imine group was not observed.

Example 4
Polymerization of the polymer and production of the film were carried out by the method described in Example 2, except that 4,4′-biphenol was changed to 4.4 g of hydroquinone (Tokyo Kasei Reagent). The weight average molecular weight was 210,000. The resulting membrane had a sulfonic acid group density of 1.8 mmol / g.

The obtained membrane had a thickness of 31 μm and proton conductivity of 85 mS / cm. The dimensional change rate was 7%, the conductivity was high, and the dimensional stability was excellent. Moreover, even if it was bent, twisted, or stretched approximately twice, it was not torn and was a high strength and high toughness film. In the infrared absorption spectrum (IR), the peak at 1592 cm ⁻¹ disappeared, and the presence of an imine group was not observed.

Example 5
Polymerization of the polymer and film formation were performed by the method described in Example 1 except that 4,4′-biphenol was changed to 6.4 g of 1,5-dihydroxynaphthalene (Tokyo Kasei Reagent). The weight average molecular weight was 240,000. The resulting membrane had a sulfonic acid group density of 2.0 mmol / g.

The obtained membrane had a thickness of 31 μm and proton conductivity of 99 mS / cm. The dimensional change rate was 16%, the conductivity was high, and the dimensional stability was excellent. Even when immersed in NMP at 100 ° C., it did not dissolve. Moreover, even if it was bent, twisted, or stretched approximately twice, it was not torn and was a high strength and high toughness film. In the infrared absorption spectrum (IR), the peak at 1592 cm ⁻¹ disappeared, and the presence of an imine group was not observed.

Comparative Example 1
A commercially available Nafion (registered trademark) 111 membrane (manufactured by DuPont) was used to evaluate ion conductivity and dimensional change rate. The Nafion (registered trademark) 111 membrane was immersed in 5% hydrogen peroxide water at 100 ° C. for 30 minutes, and subsequently immersed in 5% dilute sulfuric acid at 100 ° C. for 30 minutes, and then thoroughly washed with deionized water at 100 ° C. .

  The film thickness was 26 μm and the proton conductivity was 80 mS / cm. The dimensional change rate was 22% and the conductivity was high, but the dimensional stability was poor. Although it was not torn even when it was bent, it was easily broken when twisted or grasped with tweezers, and it was a low-strength and highly swelled film that was difficult to handle.

Comparative Example 2
Sulfonation of PEEK 10 g of polyetheretherketone (Victrex (registered trademark) PEEK (registered trademark) (manufactured by Victrex)) was reacted in 100 mL of concentrated sulfuric acid at 25 ° C. for 20 hours. By gradually throwing it into a large amount of water, a sulfonated product of polyetheretherketone was obtained. The resulting polymer had a sulfonic acid group density of 2.1 mmol / g.

  A 25 wt% N-methylpyrrolidone (NMP) solution in which the obtained sulfonated product was dissolved was cast-coated on a glass substrate and dried at 100 ° C. for 4 hours to obtain a membrane. The solubility of the polymer was good. The polymer electrolyte membrane was obtained by immersing in a large excess of pure water for 24 hours and thoroughly washing.

  The obtained membrane had a thickness of 31 μm and a proton conductivity of 105 mS / cm. Moreover, since it collapse | disintegrated in 80 degreeC hot water, the dimensional change rate was impossible to measure. The conductivity was high, but the dimensional stability and water resistance were poor. It was dissolved when immersed in NMP at 100 ° C.

Comparative Example 3
PEK was sulfonated.

  10 g of polyetherketone resin (manufactured by Victrex) was reacted in 100 mL of fuming sulfuric acid at 100 ° C. for 2 hours. After diluting with concentrated sulfuric acid, it was gradually poured into a large amount of water to obtain a polyether ketone sulfonated product SPEK-2. The sulfonic acid group density of the obtained SPEK-2 was 1.2 mmol / g.

  The SPEK-2 polymer could not be dissolved in N-methylpyrrolidone (NMP), and film formation was difficult. The composition was similar to the polymer of Example 4, but it was poor in solubility. Various evaluations could not be performed.

Comparative Example 4
The method of Example 1 was repeated except that 7.0 g of 4,4′-difluoro (N-benzohydroxylidene aniline) obtained in Synthesis Example 1 was changed to 5.2 g of 4,4′-difluorobenzophenone. Polymerization was performed. From the initial stage of polymerization, a polymer was precipitated, and the polymerization was difficult. Molecular weight could not be measured due to solvent insolubility. Since the solubility was insufficient, the film could not be formed and various measurements could not be performed.

Claims (11)

After molding a polymer electrolyte material containing at least a protective group and an ionic group, at least a part of the protective group contained in the obtained molded body is deprotected to obtain a polymer electrolyte molded body. A method for producing a molded polymer electrolyte, wherein the structural unit containing the protecting group is a structural unit represented by the following general formula (P1).

(In the general formula (P1), Ar ₁ and Ar ₂ are any divalent arylene group, A ₁ is any divalent organic group, R ₁ is any monovalent organic group, A ₂ is O or NR ₂ (R ₂ is an arbitrary monovalent organic group), m ₁ represents 0 or a positive integer. The structural unit represented by the general formula (P1) may be optionally substituted.) 2. The method for producing a molded polymer electrolyte product according to claim 1, wherein the polymer electrolyte material is an aromatic polyether polymer. The method for producing a polymer electrolyte molded body according to claim 1 or 2, wherein the structural unit represented by the general formula (P1) is a structural unit represented by the following general formula (P2).

(In General Formula (P2), R ₁ represents any monovalent organic group. The structural unit represented by General Formula (P2) may be optionally substituted.) The method for producing a molded polymer electrolyte body according to any one of claims 1 to 3, wherein the ionic group is a sulfonic acid group. The method for producing a polymer electrolyte molded body according to any one of claims 1 to 4, wherein the polymer electrolyte material further contains a structural unit represented by the following general formula (P3).

(In the general formula (P3), Ar ₃ and Ar ₄ are any divalent arylene group, B ₁ is any divalent organic group, M ¹ and M ² are hydrogen, a metal cation or an ammonium cation, a1 and a2 Represents an integer of 1 to 4, m ₂ represents 0 or a positive integer, and the structural unit represented by the general formula (P3) may be optionally substituted.) The method for producing a molded polymer electrolyte according to any one of claims 1 to 5, wherein the polymer electrolyte material further contains a structural unit represented by the following general formula (P5).

(In the general formula (P5), E is O or S, Ar ₅ and Ar ₆ are any divalent arylene group, D ₁ is a direct bond, ketone group, O or S, m ₃ is 0 or a positive integer. (The structural unit represented by formula (P5) may be optionally substituted.) A polymer electrolyte material comprising an aromatic polyether ketone copolymer containing at least 50 wt% or more of structural units represented by the following general formulas (Q1) and (Q2).

(In the general formulas (Q1) and (Q2), Ar _{11 to} Ar ₁₆ are any divalent arylene groups substantially free of ionic groups, A ₁₁ and B ₁₁ are any divalent organic groups, D ₁₁ is a direct bond, O or S, E is O or S, M ¹ and M ² are hydrogen, metal cation or ammonium cation, a1 and a2 are integers of 1 to 4, m _{11 to} m ₁₃ are 0 or positive integers However, the content molar ratio of the structural units represented by the general formulas (Q1) and (Q2) is not 0. The structural units represented by the general formulas (Q1) and (Q2) are other than ionic groups. Optionally substituted with a group.) The structural unit represented by the general formula (Q1) is a structural unit represented by the following general formula (Q3), and the structural unit represented by the general formula (Q2) is represented by the following general formula (Q4). The polymer electrolyte material according to claim 7, which is a structural unit.

(In general formulas (Q3) and (Q4), X is at least one selected from the following general formulas (X-1) to (X-6). In general formula (Q4), M1 and M2 are hydrogen atoms). , A metal cation or an ammonium cation, a1 and a2 each represent an integer of 1 to 4. The structural units represented by the general formulas (Q3) and (Q4) may be optionally substituted with a group other than an ionic group. .)

(The groups represented by the general formulas (X-1) to (X-6) may be optionally substituted with groups other than ionic groups.) A polymer electrolyte component comprising the polymer electrolyte material according to claim 7 or 8. A membrane electrode assembly comprising the polymer electrolyte material according to claim 7 or 8. A polymer electrolyte fuel cell comprising the polymer electrolyte material according to claim 7 or 8.