JP2007204578A - Polymer electrolyte material, polymer electrolyte membrane, and polymer electrolyte part, polymer electrolyte membrane, membrane electrode assembly and polymer electrolyte-type fuel cell using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer electrolyte material and a polymer electrolyte membrane which have excellent proton-conductivity, fuel separation, mechanical strength, physical durability, hot water resistance, hot methanol resistance, processability and chemical stability and, when used in a polymer electrolyte, achieves a high output, a high energy density and a long durability and a polymer electrolyte part, polymer electrolyte membrane, membrane electrode composite and polymer electrolyte-type fuel cell using these. <P>SOLUTION: The polymer electrolyte material comprises an ionic group-containing polymer having a crystallization peak observed by differential scanning calorimetry. The polymer electrolyte part, polymer electrolyte membrane, membrane electrode assembly and polymer electrolyte-type fuel cell are composed by using the polymer electrolyte material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a polymer electrolyte material and a polymer electrolyte membrane excellent in practical use capable of achieving high output, high energy capacity and long-term durability, and a polymer electrolyte component, a polymer electrolyte membrane using the polymer electrolyte material, The present invention relates to a membrane electrode assembly and a polymer 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 attracting attention. 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. As another required characteristic, in DMFC using high concentration fuel such as methanol, solvent resistance is an important characteristic as long-term durability against high concentration fuel. Other examples include chemical stability to withstand a strong oxidizing atmosphere during fuel cell operation, mechanical strength and physical durability 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 polymer electrolyte membranes. 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 lack of hot water resistance, methanol resistance, etc., problems such as loss of mechanical strength and physical durability of the membrane due to swelling and drying, problems of low softening point and inability to use at high temperatures, and disposal treatment after use There were also problems such as difficulties in recycling materials. 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, poor stability of the conformation of the polymer due to the low cohesive force of polymer molecular chains, there is a problem that insufficient mechanical strength and physical durability of the film produced.

  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, polymers with a low sulfonic acid group density composition are insoluble in the solvent due to the remaining crystalline portion, resulting in poor processability. Conversely, the sulfonic acid group density is increased to improve processability. As a result, the polymer became non-crystalline, so that it swelled remarkably in water, and not only the fuel crossover of the prepared membrane was large, but also the mechanical strength and physical durability of the prepared membrane were insufficient.

Thus, the polymer electrolyte material according to the prior art is insufficient as a means for improving economy, workability, proton conductivity, fuel crossover, solvent resistance, mechanical strength, physical durability, and thus long-term durability. Therefore, it could not be an industrially useful polymer electrolyte material for fuel cells.
"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

  In view of the background of such prior art, the present invention is excellent in proton conductivity and excellent in fuel cutoff, mechanical strength, physical durability, hot water resistance, heat resistant methanol resistance, workability, and chemical stability. , Polymer electrolyte materials and polymer electrolyte membranes that can achieve high output, high energy density and long-term durability when used as a polymer electrolyte fuel cell, and polymer electrolyte components and polymer electrolytes using the same A membrane, a membrane electrode assembly, and a polymer electrolyte fuel cell are provided.

  The present invention employs the following means in order to solve the above problems. First, as a first means, the polymer electrolyte material of the present invention is characterized by comprising an ionic group-containing polymer in which a crystallization peak is recognized by differential scanning calorimetry. The polymer electrolyte membrane, polymer electrolyte component, membrane electrode assembly, and polymer electrolyte fuel cell of the present invention are characterized by using such a polymer electrolyte material.

  Next, as a second means, the polymer electrolyte membrane of the present invention is a polymer electrolyte membrane made of an ionic group-containing polymer, and has an Elmendorf tear strength of 45 N / in under an atmosphere of 23 ° C. and a relative humidity of 50%. cm or more and 1000 N / cm or less.

  As a third means, the polymer electrolyte membrane of the present invention is a polymer electrolyte membrane made of an ionic group-containing polymer, and has a tensile strength at break of 80 MPa or more in an atmosphere of 25 ° C. and a relative humidity of 60%. 1000 MPa or less and the tensile elongation at break is 100% or more and 1000% or less.

  According to the present invention, the proton conductivity is excellent, the fuel blocking property, the mechanical strength, the physical durability, the hot water resistance, the heat resistant methanol property, the processability, the chemical stability, the high output, the high energy capacity, and Provided are a polymer electrolyte material and a polymer electrolyte membrane excellent in practical use that can achieve long-term durability, a high-performance polymer electrolyte component, a membrane electrode assembly, and a polymer electrolyte fuel cell using the same. be able to.

  Hereinafter, the present invention will be described in detail.

  First, regarding the first means of the present invention, the above-mentioned problems, that is, excellent proton conductivity, fuel cutoff, mechanical strength, physical durability, hot water resistance, hot methanol resistance, workability, and chemical stability. In addition to being excellent, we have eagerly investigated polymer electrolyte materials that can achieve high output, high energy density, and long-term durability when used as polymer electrolyte fuel cells. It has been found that the properties of barrier properties, mechanical strength, and physical durability are greatly affected by the stability of the higher-order structure of the polymer electrolyte material, that is, the crystallinity of the polymer and the crystalline / amorphous state.

  In other words, when a polymer electrolyte material made of an ionic group-containing polymer that shows a crystallization peak by differential scanning calorimetry is used, not only is it excellent in proton conductivity, fuel blocking property, and solvent resistance, By stabilizing the next structure, extremely tough mechanical strength and physical durability can be achieved, and it has been sought to solve such problems all at once.

  The polymer electrolyte material of the present invention can be evaluated by the presence or absence of a crystallization peak in differential scanning calorimetry (DSC). However, when the polymer undergoes crystallization, melting, thermal decomposition, etc., the chemical structure and higher order structure (crystalline and amorphous state) of the polymer change, so the polymer electrolyte material of the present invention is used in differential scanning calorimetry. It is necessary to evaluate whether or not a crystallization peak is observed at the first temperature increase. That is, the polymer electrolyte material of the present invention needs to have a crystallization peak observed at the first temperature rise in the differential scanning calorimetry.

  If the polymer is thermally decomposed, first confirm the polymer thermal decomposition temperature by thermogravimetric differential thermal simultaneous measurement (TG-DTA), etc., and then crystallize by raising the temperature to a temperature below the thermal decomposition temperature. It is necessary to confirm the presence or absence of a peak. If a crystallization peak is observed above the thermal decomposition temperature, the chemical structure of the polymer may have changed, and it cannot be determined that the polymer had crystallinity.

  In the polymer electrolyte material in which a crystallization peak is observed at the first temperature increase in the differential scanning calorimetry, the ionic group-containing polymer needs to be a crystalline polymer. A polyelectrolyte material composed only of an amorphous polymer does not show a crystallization peak by differential scanning calorimetry. In addition, the polymer electrolyte material of the present invention needs to have an amorphous part where crystallization proceeds with increasing temperature. By leaving the amorphous part where crystallization proceeds with increasing temperature, not only has excellent proton conductivity and fuel barrier properties, but also can achieve extremely excellent solvent resistance, mechanical strength, and physical durability. And found the present invention.

  In the present invention, the crystalline polymer means that the polymer has a crystallizable property that can be crystallized under some conditions. An amorphous polymer means a polymer that is not a crystalline polymer and that does not substantially proceed with crystallization. Therefore, even if it is a crystalline polymer, if the crystallization is not sufficiently advanced, the polymer may be in an amorphous state. With regard to the presence or absence of crystallinity of these polymers and the state of crystalline and amorphous parts, wide angle X-ray diffraction (XRD), differential scanning calorimetry (DSC), temperature modulation DSC, nuclear magnetic resonance spectrum (NMR), infrared absorption It can be evaluated by spectrum (IR), Raman spectrum, or the like.

  In the differential scanning calorimetry, when the crystallization peak is not observed at the first temperature rise, the effect of the present invention may not be obtained, which is not preferable. Specifically, when the polymer is amorphous without having crystallinity, it is divided into cases where there is no amorphous part that has crystallinity but is capable of proceeding crystallization. A polymer electrolyte material made of an amorphous polymer cannot obtain sufficient mechanical strength, physical durability, fuel barrier properties, hot water resistance, and heat resistance methanol property, and it is difficult to use high concentration fuel. High energy capacity and long-term durability cannot be achieved when used in batteries.

  In addition, when the polymer has crystallinity but no amorphous portion that can be crystallized remains, a tough polymer electrolyte membrane with insufficient processability cannot be obtained and used for a fuel cell. In some cases, long-term durability may not be achieved. In this case, once the polymer is melted, a crystallization peak may be observed when the temperature is lowered or when the temperature is raised for the second time. However, the higher-order structure of the polymer is changed, and the state of the original polymer is changed. It cannot be judged that it was amorphous.

  Thus, the present inventor has paid attention to the fact that it is important to classify the polymer electrolyte material into crystalline / amorphous as a polymer property and crystalline / amorphous as a polymer state.

  In the prior art, polymer electrolyte materials made of ionic group-containing polymers have bulky ionic groups such as sulfonic acid groups, and most of them are amorphous polymers. Polyelectrolyte materials composed of these amorphous polymers have poor cohesion of polymer molecular chains, so when molded into a film, the toughness and stability of polymer higher-order structures are insufficient, resulting in sufficient mechanical strength and physical properties. Durability could not be achieved. In addition, since the thermal decomposition temperature of the ionic group is lower than the melting temperature, it is difficult to melt mold, and usually cast molding is used, so a polymer containing solvent-insoluble crystals could not obtain a uniform and tough film. .

  Therefore, the inventors of the present invention have further described a polymer electrolyte material excellent in processability while having high crystallinity of polymer molecular chains, and further has a higher polymer structure and characteristics as a polymer electrolyte material. By intensively studying the relationship, and leaving an amorphous part that can proceed to crystallize in the crystalline polymer, not only high proton conductivity and fuel barrier properties, but also excellent solvent resistance, extremely tough mechanical strength, The inventors have found a polymer electrolyte material of the present invention that can achieve physical durability.

  In the polymer electrolyte material of the present invention, it is more preferable that the crystallization heat amount ΔH per unit of dry polymer unit g measured by differential scanning calorimetry (DSC) is 2 J / g or more. As the differential scanning calorimetry (DSC), a temperature modulation DSC can be more preferably used in terms of measurement accuracy. Among them, ΔH is more preferably 5 J / g or more, more preferably 10 J / g or more, and most preferably 15 J / g or more in terms of mechanical strength, physical durability, heat resistant methanol resistance, and fuel cutoff. . When ΔH is less than 2 J / g, there is a case where the crystallinity or the amount of an amorphous part capable of proceeding crystallization is insufficient, and the effects of the present invention such as mechanical strength and physical durability may not be sufficiently obtained. Yes, not preferred.

  The confirmation of the presence or absence of a crystallization peak and temperature measurement of crystallization by temperature-modulated DSC of the polymer electrolyte material are performed by the method of the example. The pyrolysis temperature is preferably confirmed separately by simultaneous thermogravimetric differential heat measurement or the like.

  The crystallization peak is observed in an irreversible process, and the temperature is observed above the glass transition temperature and below the melting temperature. The amount of crystallization heat can be calculated from the area of the crystallization peak. However, in the case of a polymer electrolyte material having a sulfonic acid group, the crystallization temperature, the thermal decomposition temperature, and the melting temperature are close to each other. In the present invention, a value obtained by doubling the amount of heat from the low temperature side to the peak top is defined as the amount of crystallization heat.

  The polymer electrolyte material of the present invention more preferably has a crystallinity of less than 0.5% as measured by wide-angle X-ray diffraction from the viewpoint of mechanical strength and physical durability. When the crystallinity is 0.5% or more, workability is insufficient and a uniform and tough electrolyte membrane may not be obtained, or toughness may be insufficient and long-term durability may be insufficient. .

  Determination of the presence or absence of crystals and measurement of crystallinity by wide-angle X-ray diffraction of such a polymer electrolyte material are performed by the methods described in the examples.

  The polymer electrolyte material of the present invention is suitably used for polymer electrolyte parts. In the present invention, the polymer electrolyte component means a component containing the polymer electrolyte material of the present invention. In the present invention, specific shapes of parts include plates (including films and films), plates, fibers, hollow fibers, particles, lumps, micropores, coatings, and foams. It can take various forms depending on usage, such as body. 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 membrane of the present invention can be applied to various uses. For example, it can be applied to medical applications such as extracorporeal circulation columns and artificial skin, applications for filtration, ion exchange resin applications, various structural materials, and electrochemical applications. It is also suitable as an artificial muscle. 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.

  Next, the second means of the present invention will be described. The polymer electrolyte membrane of the present invention is a polymer electrolyte membrane made of an ionic group-containing polymer, and has an Elmendorf tear strength of 45 N / cm or more and 1000 N / cm measured in an atmosphere of 23 ° C. and a relative humidity of 50%. A polymer electrolyte membrane.

  The inventors of the present invention have made extensive studies on a polymer electrolyte membrane that can achieve long-term durability when used as a polymer electrolyte fuel cell, and the polymer electrolyte has a mechanical strength that is particularly excellent in tear strength. Focusing on the improvement of the physical durability of the fuel cell, the present inventors have found a polymer electrolyte membrane of the present invention that is particularly excellent in tear strength. When the polymer electrolyte fuel cell is operated under practical conditions, the swelling and shrinkage corresponding to the start and stop of the fuel cell is repeated. In general, polymer electrolyte membranes require high proton conductivity, so they need to contain a large amount of moisture. However, the mechanical strength and physical durability of the membrane are insufficient under the conditions of repeated swelling and shrinkage. However, there was a problem that the membrane was broken. The inventors of the present invention are effective in improving the cohesive strength of polymer molecular chains in order to improve the physical durability against the swelling and shrinkage, and have focused on the tear strength that correlates with the cohesiveness of the polymer molecular chains.

  The polymer electrolyte membrane of the present invention has an Elmendorf tear strength of more preferably 80 N / cm or more, most preferably 120 N / cm or more in terms of physical durability. If the Elmendorf tear strength is less than 45 N / cm, the film may be broken if used under conditions where power generation is continued for a long time or swelling and drying are repeated, such being undesirable. The higher the Elmendorf tear strength is, the more preferable, but the higher the value, the lower the proton conductivity, so the practical upper limit is 1000 N / cm. The Elmendorf tear strength of such a polymer electrolyte membrane is measured by the method described in the examples.

  Finally, the third means of the present invention will be described. The polymer electrolyte membrane of the present invention is a polymer electrolyte membrane made of an ionic group-containing polymer, and has a tensile strength at break of 80 MPa to 1000 MPa in an atmosphere of 25 ° C. and a relative humidity of 60%. The polymer electrolyte membrane is 100% or more and 1000% or less.

  In order to achieve long-term stability under practical conditions, the present inventors have intensively studied a polymer electrolyte membrane that can achieve long-term durability when a polymer electrolyte fuel cell is obtained. Focusing on the need for a film excellent in both tensile rupture strength and tensile rupture elongation, among other mechanical strengths, the polymer electrolyte membrane of the present invention excellent in both tensile rupture strength and tensile rupture elongation was found. .

  The tensile strength at break of the polymer electrolyte membrane of the present invention is more preferably 100 MPa or more, and most preferably 120 MPa or more. The larger the tensile strength at break, the more preferable, but the larger the value, the higher the interfacial resistance with the catalyst layer, so the practical upper limit is 1000 MPa. Further, the tensile elongation at break is more preferably 250% or more, and further preferably 350% or more. Most preferably, the tensile strength at break in an atmosphere of 25 ° C. and a relative humidity of 60% is 120 MPa to 1000 MPa and the tensile elongation at break is 350% to 1000%. When the tensile strength at break is less than 80 MPa, creep resistance is insufficient and damage due to thinning may be easily generated. Further, when the tensile elongation at break is less than 100%, the toughness is insufficient, and the film may be broken if used under conditions where power generation is continued for a long time or swelling and drying are repeated, such being undesirable.

  From the viewpoint of long-term durability, the polymer electrolyte membrane of the present invention more preferably has a tensile elastic modulus of 0.8 GPa or more and 5 GPa or less in an atmosphere of 25 ° C. and a relative humidity of 60%. More preferably, it is 1 GPa or more and 3 GPa or less, Most preferably, it is 1.2 GPa or more and 2.5 GPa or less. When the tensile elastic modulus is less than 0.8 GPa, the long-term durability may be insufficient due to poor creep resistance. If the tensile modulus exceeds 5 GPa, there may be a problem in adhesion to the catalyst layer, or the film may be easily broken due to insufficient toughness.

  The polymer electrolyte membrane of the present invention more preferably has a tensile yield point strength of 30 MPa or more in an atmosphere of 25 ° C. and a relative humidity of 60%. Furthermore, Preferably, it is 50 MPa or more. If it is less than 30 MPa, the long-term durability may be insufficient due to poor creep resistance, and the film may be broken if used under conditions such as repeated swelling and drying.

  The tensile strength at break, tensile elongation at break, tensile modulus, and tensile yield strength of such a polymer electrolyte membrane can be determined by measuring tensile strength and elongation. The tensile strength / elongation measurement is performed by the method described in Examples.

  The polymer electrolyte material and the polymer electrolyte membrane of the present invention are excellent in solvent resistance, that is, immersed in N-methylpyrrolidone at 100 ° C. for 2 hours from the viewpoint of fuel barrier properties and high energy capacity by using high concentration fuel. More preferably, the subsequent 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 polymer crystallinity is insufficient, so that the mechanical strength and physical durability are insufficient, or a high-temperature and high-concentration methanol aqueous solution is used as the fuel. When used for DMFC, it is not preferable because the membrane 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. The weight loss of such a polymer electrolyte material relative to N-methylpyrrolidone is measured by the method of the example.

  In the present invention, being excellent in hot water resistance and hot methanol resistance means that the dimensional change (swelling) in hot water and hot methanol is 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. Furthermore, when the hot water resistance or the hot methanol property is inferior, when a high concentration fuel such as a high concentration methanol aqueous solution is used, the polymer electrolyte membrane and the binder of the catalyst layer dissolve, which is not preferable. 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 ionic group-containing polymer used in the polymer electrolyte material and the polymer electrolyte membrane of the present invention is more preferably a hydrocarbon polymer. The ionic group-containing hydrocarbon polymer referred to in the present invention means a polymer having an ionic group other than a perfluoro polymer.

  Here, the perfluoro polymer means a polymer in which most or all of the hydrogen atoms in the alkyl group and / or alkylene group in the polymer are substituted with fluorine atoms. In the present specification, a polymer in which 85% or more of hydrogen of an alkyl group and / or an alkylene group in a polymer is substituted with a fluorine atom is defined as a perfluoro polymer.

  Representative examples of the perfluoro polymer having an ionic group of the present invention include Nafion (registered trademark) (manufactured by DuPont), Flemion (registered trademark) (manufactured by Asahi Glass Co., Ltd.), and Aciplex (registered trademark) (manufactured by Asahi Kasei Co., Ltd.). ) And other commercial products. The structure of the perfluoro polymer having these ionic groups can be represented by the following general formula (N1).

[In formula (N1), n ₁ and n ₂ each independently represents a natural number. k ₁ and _{k 2} each independently represent an integer of 0 to 5. ]
In the perfluoro-based polymer having these ionic groups, a hydrophobic portion and a hydrophilic portion in the polymer form a clear phase structure, so that a water channel called a cluster is formed in the polymer in a water-containing state. In such a water channel, fuel such as methanol can easily move, and a reduction in fuel crossover cannot be expected. Due to the bulky side chain, no crystallization peak is observed in the differential scanning calorimetry, which is not preferable. Moreover, since the packing of the polymer molecular chain is poor, the tear strength and tensile strength at break are small, which is not preferable.

  Specific examples for obtaining the polymer electrolyte material and polymer electrolyte membrane of the present invention will be given. The polymer electrolyte material of the present invention can be obtained by deprotecting at least a part of the protecting group from the polymer electrolyte material comprising an ionic group-containing polymer having a protecting group. In the polymer electrolyte membrane of the present invention, a polymer electrolyte material made of an ionic group-containing polymer having a protective group is molded into a film shape, and then at least a part of the protective group of the molded polymer electrolyte membrane is formed. Although it can obtain by deprotecting, it is not limited to this.

  As other achievement means for obtaining the polymer electrolyte material and the polymer electrolyte membrane of the present invention, a polymer electrolyte material comprising a crystalline ionic group-containing polymer whose melting temperature is lower than the thermal decomposition temperature of the ionic group, Alternatively, a polymer electrolyte material made of a crystalline ionic group-containing polymer having extremely high heat resistance and capable of being melt-molded was produced, and a polymer complex with an organic compound, polymer, organic metal, or the like was formed by a melt-molding method. Examples thereof include a method of removing an organic compound, a polymer, and an organic metal from the polymer electrolyte material.

  Specific examples of the protecting group used in the present invention include protecting groups generally used in organic synthesis, and the protecting group is temporarily introduced on the assumption that it is removed at a later stage. It is a substituent that protects a highly reactive functional group and renders it inactive to the subsequent reaction, and can be deprotected and returned to the original functional group after the reaction. 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).

  Such protection reactions include, for example, Theodora W. Greene, “Protective Groups in Organic Synthesis”, US, John Wiley & Sons, Inc), 1981, which can be preferably used. It can be appropriately selected in consideration of the reactivity and yield of the protection reaction and deprotection reaction, the stability of the protecting group-containing state, the production cost, and the like. In addition, the stage for introducing a protecting group in the polymerization reaction may be from the monomer stage, the oligomer stage, or the polymer stage, and can be selected for convenience.

  Specific examples of the protection reaction include protecting / deprotecting a ketone moiety with an acetal or ketal moiety, and protecting / deprotecting a ketone moiety with a heteroatom analog of the acetal or ketal moiety, such as thioacetal or thioketal. The method of doing is mentioned. These methods are described in Chapter 4 of “Protective Groups in Organic Synthesis”. Further, a method for protecting / deprotecting between a sulfonic acid and a soluble ester derivative, a method for protecting / deprotecting by introducing a t-butyl group as a soluble group into an aromatic ring and det-butylating with an acid, etc. . However, it is not limited to these, and any protective group can be preferably used. In terms of improving the solubility in a general solvent, an aliphatic group, particularly an aliphatic group containing a cyclic moiety, is preferably used as a protective group in terms of large steric hindrance.

  The position of the functional group for introducing the protective group is more preferably the main chain of the polymer. Since the polymer electrolyte material of the present invention introduces a protecting group into a polymer having good packing for the purpose of improving processability, the effect of the present invention can be sufficiently obtained even if a protecting group is introduced into the side chain portion of the polymer. There may not be. Here, the functional group present in the main chain of the polymer is defined as a functional group that breaks the polymer chain when the functional group is deleted. For example, this means that if the ketone group of the aromatic polyether ketone is deleted, the benzene ring and the benzene ring are broken.

  In terms of reactivity and stability, the protection reaction is more preferably a method of protecting / deprotecting a ketone moiety with an acetal or ketal moiety, a heteroatom analog of the ketone moiety with an acetal or ketal moiety, such as thioacetal, This is a method of protecting / deprotecting with thioketal. The polymer electrolyte material and the polymer electrolyte membrane of the present invention preferably contain at least one selected from the following general formulas (P1) and (P2) as a structural unit containing a protective group.

(In the general formulas (P1) and (P2), Ar _{1 to} Ar ₄ are any divalent arylene group, R ₁ and R ₂ are at least one group selected from H and an alkyl group, and R ₃ is any And E represents O or S, and each may represent two or more groups, and the groups represented by the general formulas (P1) and (P2) may be optionally substituted.)
Among them, in the general formulas (P1) and (P2), E is O in terms of the odor, reactivity, stability, etc. of the compound, that is, the ketone moiety is protected / deprotected with an acetal or ketal moiety. The method is most preferred.

  The ionic group-containing polymer of 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, physical durability 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 a main chain structure having sufficient mechanical strength and physical durability, for example, used as an engineering plastic is preferable.

  Specific examples of the polymer having an aromatic ring in the main chain used in the ionic group-containing polymer of the present invention include polysulfone, polyethersulfone, polyphenylene oxide, polyarylene ether-based polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, and polyparaphenylene. , Polyarylene polymers, polyarylene ketones, polyether ketones, polyarylene phosphine oxides, polyether phosphine oxides, polybenzoxazoles, polybenzthiazoles, polybenzimidazoles, polyamides, polyimides, polyetherimides, polyimidesulfones, etc. Examples thereof include polymers containing at least one component.

  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 Polymers such as ether phosphine oxide are more preferred from the viewpoints of mechanical strength, physical durability, 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) can be given.

(Here, Z ¹ and Z ² each represent an organic group containing an aromatic ring, and each may represent two or more groups. At least one of Z ¹ and Z ² is ionic.) 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, physical durability and production cost. Among these, from the viewpoint of mechanical strength, physical durability, and production cost, an aromatic polyether polymer in which Y ² is O is more preferable, and the repeating unit represented by the general formula (T1-3) is most preferable. The aromatic polyetherketone-based polymer in which Y1 is a -CO- group and Y2 is O is most preferable.

(Here, Z ¹ and Z ² each represent an organic group containing an aromatic ring, and each may represent two or more groups. At least one of Z ¹ and Z ² is ionic.) A and b each independently represents 0 or a positive integer, provided that a and b are not 0 at the same time.)
Preferred organic groups as Z ¹ and Z ² are a phenylene group, a naphthylene group, and a biphenylene group. These include those containing ionic groups. Moreover, although you may substitute by groups other than an ionic group, the direction where it is unsubstituted is more preferable at the point of crystallinity provision. Furthermore, a phenylene group having a phenylene group and an ionic group is preferable, and a p-phenylene group having a p-phenylene group and an ionic group is most preferable.

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.

  Here, the aromatic polyether ketone polymer is a general term for polymers having at least an ether bond and a ketone bond in the molecular chain, and is a polyether ketone, a polyether ketone ketone, a polyether ether ketone, a poly ether. It includes ether ether ketone ketone, polyether ketone ether ketone ketone, polyether ketone sulfone, polyether ketone phosphine oxide, polyether ketone nitrile and the like, and does not limit the specific polymer structure. Those containing a large amount of phosphine oxide or nitrile may have insufficient solvent solubility in the ionic group-containing polymer having a protecting group, and if they contain a large amount of sulfone, they are resistant to solvents such as heat-resistant methanol and hot water. Sexuality may be insufficient.

In the ionic group-containing polymer of the present invention, R ₁ and R ₂ in the general formula (P1) are more preferably an alkyl group in terms of stability, and more preferably an alkyl group having 1 to 6 carbon atoms. And most preferably an alkyl group having 1 to 3 carbon atoms. Moreover, as R < ₃ > in general formula (P2), it is more preferable that it is a C1-C7 alkylene group from a stability point, Most preferably, it is a C1-C4 alkylene group. Specific examples of R3 include —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —C ( CH ₃ ) ₂ CH (CH ₃ ) —, —C (CH ₃ ) ₂ O (CH ₃ ) ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH ₂ C (CH ₃ ) ₂ CH ₂ — and the like. However, it is not limited to these.

The ionic group-containing polymer used in the present invention has at least the general formula (P2) in terms of stability such as hydrolysis resistance among the structural units of the general formula (P1) or (P2). Is more preferably used. Furthermore, R _{3 in the} general formula (P2) is preferably an alkylene group having 1 to 7 carbon atoms, that is, a group represented by C _n1 H _2n1 (n1 is an integer of 1 to 7). From the viewpoint of ease of synthesis, at least one selected from —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, and —CH ₂ CH ₂ CH ₂ — is most preferable.

A preferable organic group as Ar _{1 to} Ar ₄ in the general formulas (P1) and (P2) is a phenylene group, a naphthylene group, or a biphenylene group. These may be optionally substituted. As the ionic group-containing polymer of the present invention, Ar ₃ and Ar ₄ in the general formula (P2) are both phenylene groups, that is, represented by the following general formula (P3) because of solubility and easy availability of raw materials. More preferably, Ar ₃ and Ar ₄ are both p-phenylene groups.

(In General Formula (P3), n1 is an integer of 1 to 7. The structural unit represented by General Formula (P3) 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, aromatic polyether polymers containing the structural units represented by the general formulas (P1) and (P2) are represented by the following general formulas (P1-1) and ( It is possible to synthesize by an aromatic nucleophilic substitution reaction with an aromatic active dihalide compound using the compound represented by P2-1). The structural units represented by the general formulas (P1) and (P2) may be derived from either the divalent phenol compound or the aromatic active dihalide compound, but the divalent phenol is considered in consideration of the reactivity of the monomer. More preferably, it is derived from a compound.

(In the general formulas (P1-1) and (P2-1), Ar _{1 to} Ar ₄ are any divalent arylene group, R ₁ and R ₂ are at least one group selected from H and an alkyl group, R ₃ represents an arbitrary alkylene group, and E represents O or S. The compounds represented by the general formula (P1-1) and the general formula (P2-1) may be optionally substituted.
Specific examples of particularly preferred dihydric phenol compounds used in the present invention include compounds represented by the following general formulas (r1) to (r10), and derivatives derived from these dihydric phenol compounds.

  Among these dihydric phenol compounds, the compounds represented by the general formulas (r4) to (r10) are more preferable from the viewpoint of stability, and more preferably the compounds represented by the general formulas (r4), (r5), and (r9). The compound represented by the general formula (r4) is most preferred.

  In the present invention, a method for protecting a ketone moiety with an acetal and / or ketal includes a method in which a precursor compound having a ketone group is reacted with a monofunctional and / or bifunctional alcohol in the presence of an acid catalyst. For example, by reacting the ketone precursor 4,4′-dihydroxybenzophenone in a solvent such as a monofunctional and / or difunctional alcohol, aliphatic or aromatic hydrocarbon in the presence of an acid catalyst such as hydrogen bromide. Can be manufactured. The alcohol is an aliphatic alcohol having 1 to 20 carbon atoms. An improved method for producing acetal and / or ketal monomers for use in the present invention is to react the ketone precursor 4,4'-dihydroxybenzophenone with a bifunctional alcohol in the presence of an alkyl orthoester and a solid catalyst. Become.

  The most preferred ketal monomers are 4,4'-dihydroxybenzophenone, excess glycol, excess trialkyl orthoformate and about 0.1 to about 5 g of montmorillonite clay K-10, preferably about 0.5 to about 0.5 g of ketone. It is produced by heating a mixture of 2.5 g of clay to distill off the alcohol obtained from the orthoformate. The ketal-containing monomer 2,2-bis (4-hydroxyphenyl) -1,3-dioxolane can be obtained in excellent yield (60% to almost quantitative) with a reaction time within 48 hours.

  In the present invention, the method for deprotecting at least a part of the ketone moiety protected with acetal and / or ketal 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, physical durability, and solvent resistance, after being molded into a film or the like The method of acid treatment with 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 appropriately selected.

  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 aromatic active dihalide compound is not particularly limited as long as it can have a high molecular weight by an aromatic nucleophilic substitution reaction with a dihydric phenol compound. More preferable specific examples of the aromatic active dihalide compound include 4,4′-dichlorodiphenyl sulfone, 4,4′-difluorodiphenyl sulfone, 4,4′-dichlorodiphenyl ketone, 4,4′-difluorodiphenyl ketone, 4,4′-dichlorodiphenylphenylphosphine oxide, 4,4′-difluorodiphenylphenylphosphine oxide, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile and the like can be mentioned. Among these, 4,4′-dichlorodiphenyl ketone and 4,4′-difluorodiphenyl ketone are more preferable from the viewpoints of imparting crystallinity, mechanical strength, physical durability, heat resistance methanol resistance, and fuel crossover suppressing effect, and polymerization activity. To 4,4′-difluorodiphenyl ketone. These aromatic active dihalide compounds can be used alone, but a plurality of aromatic active dihalide compounds can also be used in combination.

  As a polymer electrolyte material synthesized using 4,4′-dichlorodiphenyl ketone or 4,4′-difluorodiphenyl ketone as the aromatic active dihalide compound, a constituent represented by the following general formula (P4) is further included. It is included and is preferably used. The aromatic polyether-based polymer is a structural unit obtained by deprotecting the ketal site in the general formula (P3) and converting it into a ketone group, which becomes a component that imparts intermolecular cohesion and crystallinity, and serves as a fuel. Highly dimensional stability, mechanical strength, physical durability in methanol water used, and a material excellent in high tear strength and repeated swelling / drying resistance in polymer electrolyte fuel cells using hydrogen as fuel. Since it becomes an effective component, it is preferably used.

(The structural unit represented by the general formula (P4) may be optionally substituted, but does not contain an ionic group.)
The aromatic polyether polymer used in the present invention includes the following general formula (P5) together with the structural unit represented by the general formula (P1) and / or (P2) and the general formula (P4). Monomers having an ionic group exemplified by those having a structural unit represented are also preferably used in combination. 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. Examples of monomers having sulfonic acid groups as ionic groups include 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone, 3,3′-disulfonate-4,4′-difluorodiphenylsulfone, 3 3,3′-disulfonate-4,4′-dichlorodiphenyl ketone, 3,3′-disulfonate-4,4′-difluorodiphenyl ketone, 3,3′-disulfonate-4,4′-dichlorodiphenylphenylphosphine And 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.

  Polymer electrolyte material synthesized using 3,3′-disulfonate-4,4′-dichlorodiphenyl ketone, 3,3′-disulfonate-4,4′-difluorodiphenyl ketone as a monomer having an ionic group Is further preferably used because it further contains a structural unit represented by the following general formula (P5). The aromatic polyether polymer has a high crystallinity characteristic of a ketone group, and is a component superior in heat-resistant methanol property to a sulfone group, and has high dimensional stability at high temperatures in methanol water used as a fuel. Since it becomes an effective component for a material excellent in strength and physical durability, it is more preferably used. 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.

(In General Formula (P5), M ¹ and M ² represent hydrogen, a metal cation, an ammonium cation, and a 1 and a 2 each represent an integer of 1 to 4. The structural unit represented by General Formula (P5) is further optionally substituted. May be.)
When an aromatic polyether polymer is obtained by an aromatic nucleophilic substitution reaction of an aromatic active dihalide compound and a divalent phenol compound, at least the general formula (P1-1) and / or the divalent phenol compound is obtained. Although it is necessary to use what is represented by (P2-1), it is also possible to use other dihydric phenol compounds together. As the dihydric phenol compound to be copolymerized, 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. Absent. 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 in 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.

  Preferable specific examples of the dihydric phenol residue used in combination include divalent phenol residues represented by the following general formulas (X-1) to (X-17). 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.

(N and m are integers of 1 or more, and Rp represents an arbitrary organic group.)
These may have a substituent and an ionic group. Those having an aromatic ring in the side chain are also preferred specific examples. Moreover, these can also be used together as needed.

  The dihydric phenol residue represented by these general formulas (X-1) to (X-17) is a dihydric phenol residue that can improve crystallinity depending on the method of use. Due to the improvement in crystallinity, the resulting polymer electrolyte material can be preferably used because it can exhibit excellent performances such as mechanical strength, physical durability, solvent resistance, fuel cutoff, and long-term durability. Among these, a dihydric phenol residue represented by the general formulas (X-1) to (X-5), (X-7), (X-14), and (X-17) is most preferable, Preferably, it is a dihydric phenol residue represented by general formulas (X-1) to (X-5).

  In the polymer electrolyte material and polymer electrolyte membrane of the present invention, the content of the structural unit selected from the general formula (P1) or (P2) is not particularly limited, but crystallinity, mechanical strength, physical From the viewpoint of durability, heat resistance methanol resistance and fuel crossover suppression effect, a smaller amount is preferable, a very small amount is more preferable, and all are deprotected are most preferable.

  2 of the general formula (P1) and / or (P2) with respect to the total molar amount of the dihydric phenol residue consisting of the general formula (P1) and / or (P2) and the other dihydric phenol residue. It is preferable that the content of the hydric phenol residue is 50 mol% or less. In particular, it is preferably 20% by mole or less, more preferably 5% by mole or less, most preferably less than the detection limit from the viewpoint of mechanical strength, physical durability, fuel crossover suppression effect and dimensional stability. preferable. When the structural unit represented by the general formula (P1) and / or (P2) is contained in an amount of 50 mol% or more, the breaking strength, elastic modulus, hot water resistance, and fuel crossover suppressing effect may be insufficient.

  In the polymer electrolyte material of the present invention, the content of the structural unit selected from the general formula (P1) or (P2) is as follows: nuclear magnetic resonance spectrum (NMR), thermogravimetry (TGA), thermal desorption- It can be measured by generated gas analysis by mass spectrometry (TPD-MS), pyrolysis gas chromatograph, pyrolysis GC-MS, infrared absorption spectrum (IR) and the like.

  When the amount of the protecting group for reducing crystallinity contained in the polymer electrolyte material used in the present invention is large, a nuclear magnetic resonance spectrum (NMR) is suitable for quantifying the protecting group because of solvent solubility. is there. However, if the amount of protecting group is very small and insoluble in the solvent, it may be difficult to accurately quantify by NMR. In such a case, the generated gas analysis by temperature-programmed thermal desorption-mass spectrometry (TPD-MS), pyrolysis gas chromatograph, or pyrolysis GC-MS is a suitable quantitative method.

For example, when the polymer electrolyte material of the present invention contains the general formula (P2) as a structural unit and R3 is —CH ₂ CH ₂ —, temperature-programmed thermal desorption-mass spectrometry (TPD-MS) ) To detect at least C ₂ H ₄ O gas and / or C ₄ H ₈ O ₂ gas.

In the amount of gas generated in the polymer electrolyte material, the sum of the amount of gas generated by C ₂ H ₄ O and the amount of gas generated by C ₄ H ₈ O ₂ may be 20% by weight or less based on the dry weight of the polymer electrolyte material. More preferred. The solvent-soluble polymer electrolyte material precursor is more preferably 1% by weight or more and 20% by weight or less from the viewpoint of solvent solubility. On the other hand, when the polymer electrolyte material requires solvent resistance, mechanical strength, and physical durability, it is more preferably 1% by weight or less, more preferably 0.3% by weight or less, and most preferably Is 0.1% by weight or less.

The content of the ketal group in the polymer electrolyte material and the polymer electrolyte membrane by the TPD-MS method is quantified by the method of the example.

In the polymer electrolyte membrane of the present invention, all of the ketone sites protected with acetal and / or ketal are deprotected, particularly from the viewpoint of mechanical strength, physical durability, heat resistance methanol resistance and fuel crossover suppression effect. It is more preferable to return to. However, a portion of the ketone moiety protected with acetal and / or ketal may remain as long as it does not adversely affect the hot water resistance, hot methanol resistance and fuel crossover suppression effect. Here, all the ketone sites protected with acetal and / or ketal are deprotected means that the residual amount of the ketone site protected with acetal and / or ketal by the above analysis method is below the detection limit. To do.

  Examples of the content of the acetal group and the ketal group contained in the ionic group-containing polymer having a protecting group used in the present invention include the above general formulas (P1-1) and (P2-1) as divalent phenol compounds. Is used, the total molar amount of the general formulas (P1-1) and (P2-1) is preferably 5 mol% or more with respect to the total molar amount of the dihydric phenol compound. If the total molar amount of the said general formula (P1-1) and (P2-1) is less than 5 mol%, solubility may become insufficient and film forming property may become inadequate. The total molar amount of the general formulas (P1-1) and (P2-1) is more preferably 30 mol% or more, and still more preferably 45 mol% or more, from the viewpoint of improving the solubility. Those containing a large amount of the structural unit represented by the general formula (P1) and / or (P2) are excellent in solubility and workability, and therefore, in producing an extremely tough polymer electrolyte membrane, It can be particularly preferably used as an ionic group-containing polymer having

  Since the ionic group-containing polymer of the present invention has an ionic group, the polymer electrolyte material and the polymer electrolyte membrane have high proton conductivity.

  The ionic group used in the present invention is preferably an atomic group having a negative charge, and 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, as the ionic group-containing polymer, Na, K, and Li that are inexpensive and can be easily proton-substituted are more preferably used.

  Two or more kinds of these ionic groups can be contained in the ionic group-containing polymer, and it may be preferable to combine 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.

  When the ionic group-containing polymer of the present invention has a sulfonic acid group, the sulfonic acid group density is preferably from 0.1 to 5 mmol / g, more preferably from 0.3 to 5 in terms of proton conductivity and fuel blocking properties. 3 mmol / g, most preferably 0.5 to 2.5 mmol / g. By setting the sulfonic acid group density to 0.1 mmol / g or more, conductivity, that is, output performance can be maintained, and by setting it to 5 mmol / g or less, it is sufficient when used as an electrolyte membrane for a fuel cell. It is possible to obtain excellent fuel barrier properties, mechanical strength when containing water, and physical durability.

  Here, the sulfonic acid group density is the molar amount of sulfonic acid group introduced per unit dry weight of the polymer electrolyte material or polymer electrolyte membrane, and the greater the value, the higher the degree of sulfonation. Show. The sulfonic acid group density can be measured by elemental analysis or neutralization titration. Among these, it is preferable to calculate from the S / C ratio using an elemental analysis method for ease of measurement. However, when a sulfur source other than a sulfonic acid group is included, the ion exchange capacity is obtained by a neutralization titration method. You can also The polyelectrolyte material and the polyelectrolyte membrane of the present invention include an embodiment that is a complex composed of a polymer having an ionic group and other components, as will be described later. It is assumed that the total amount of

The procedure for neutralization titration is as follows. The measurement shall be performed three times or more and the average shall be taken.
(1) The sample is pulverized by a mill, and in order to make the particle size uniform, the sample is passed through a 50-mesh mesh sieve and the sample passed through the sieve is used as the measurement sample.
(2) Weigh the sample tube (with lid) with a precision balance.
(3) About 0.1 g of the sample of (1) is put into a sample tube and vacuum dried at 40 ° C. for 16 hours.
(4) Weigh the sample tube with the sample and determine the dry weight of the sample.
(5) Dissolve sodium chloride in a 30 wt% aqueous methanol solution to prepare a saturated saline solution.
(6) Add 25 mL of the saturated salt solution of (5) above to the sample, and stir for 24 hours for ion exchange.
(7) Titrate the resulting hydrochloric acid with 0.02 mol / L aqueous sodium hydroxide. Two drops of a commercially available titration phenolphthalein solution (0.1% by volume) as an indicator are added, and the point at which light reddish purple is obtained is the end point.
(8) The sulfonic acid group density is determined by the following formula.

Sulfonic acid group density (mmol / g) =
[Concentration of sodium hydroxide aqueous solution (mmol / ml) × Drip amount (ml)] / Dry weight of sample (g)
Examples of a method for introducing an ionic group in order to obtain these ionic group-containing 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.

  As a polymerization method using a monomer having an ionic group, a monomer having an ionic group in a repeating unit may be used. Such a method is described in, for example, Journal of Membrane Science, 197, 2002, p.231-242. This method is very preferable because the sulfonic acid group density of the polymer can be easily controlled and can be easily applied industrially.

  The method for introducing an ionic group in a polymer reaction will be described with an example. For example, introduction of a phosphonic acid group into an aromatic polymer may be performed by, for example, Polymer Preprints (Japan), 51, 2002, p. 750. It is possible by the method described in the above. Introduction of a phosphate group into an aromatic polymer can be achieved by, for example, phosphoric esterification of an aromatic polymer having a hydroxyl group. Introduction of a carboxylic acid group into an aromatic polymer can be performed by oxidizing an aromatic polymer having an alkyl group or a hydroxyalkyl group, for example. Introduction of a sulfate group into an aromatic polymer can be achieved by, for example, sulfate esterification of an aromatic polymer having a hydroxyl group. As a method for sulfonating an aromatic polymer, that is, a method for introducing a sulfonic acid group, for example, a method described in JP-A-2-16126 or JP-A-2-208322 is known.

  Specifically, for example, an aromatic polymer 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 sulfonates an aromatic polymer, and sulfur trioxide or the like can be used in addition to the above. When the aromatic polymer 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.

  The polymer electrolyte membrane of the present invention preferably has a proton conductivity per unit area / unit thickness of 10 mS / cm or more. More preferably, it is 20 mS / cm or more, More preferably, it is 50 mS / cm or more. Such proton conductivity is measured by the constant potential alternating current impedance method, which is performed as quickly as possible after immersing a membrane sample in pure water at 25 ° C. for 24 hours, taking it out in an atmosphere of 25 ° C. and relative humidity 50% to 80%. Can do.

  When the proton conductivity per unit area and unit thickness is 10 mS / cm or more, sufficient proton conductivity, that is, sufficient battery output can be obtained when used as a polymer electrolyte membrane for a fuel cell. Higher proton conductivity is preferable, but if it is too high, a membrane with high proton conductivity tends to be dissolved or disintegrated by a fuel such as methanol water, and the fuel permeation amount tends to increase. Is preferably 5000 mS / cm.

  In addition, the polymer electrolyte membrane of the present invention preferably has a methanol permeation amount per unit area / unit thickness of 100 nmol / min / cm or less with respect to a 1 mol% aqueous methanol solution at 20 ° C. More preferably, it is 50 nmol / min / cm or less, More preferably, it is 10 nmol / min / cm or less. In a fuel cell using a membrane of a polymer electrolyte material, it is desired that the fuel permeation amount be small in order to maintain a high fuel concentration from the viewpoint of obtaining a high output and a high energy capacity in a region where the fuel concentration is high. It is. On the other hand, from the viewpoint of ensuring proton conductivity, 0.01 nmol / min / cm or more is preferable.

The proton conductivity per unit area measured under the above conditions is preferably ³ S / cm ² or more, more preferably 5 S / cm ² or more, and even more preferably 7 S / cm ² or more. By setting it to ³ S / cm ² or more, high output is obtained as a battery. On the other hand, since a membrane with high proton conductivity tends to be dissolved or disintegrated by a fuel such as methanol water and the fuel permeation amount tends to increase, the practical upper limit is 500 S / cm ² .

In addition, the polymer electrolyte membrane of the present invention preferably has a methanol permeation amount per unit area of 5 μmol / min / cm ² or less with respect to a 1 mol% aqueous methanol solution at 20 ° C. This is because, in a fuel cell using a polymer electrolyte membrane, it is desired that the fuel permeation amount be small in order to maintain a high fuel concentration from the viewpoint of obtaining a high output and a high energy capacity in a region where the fuel concentration is high. . From this viewpoint, the methanol permeation amount is more preferably ² μmol / min / cm ² or less, and most preferably 1 μmol / min / cm ² or less. From the viewpoint of ensuring proton conductivity, it is preferably 0.01 μmol / min / cm ² or more.

  When the polymer electrolyte material of the present invention is used in DMFC, it is preferable to achieve the low methanol permeation amount and the high proton conductivity as described above. It is easy to achieve only one of these in the prior art, but it is possible to achieve both high output and high energy capacity only when both are achieved.

  Particularly preferred specific examples of the polymer electrolyte material and the polymer electrolyte membrane of the present invention will be given. Aromatic polyether ketone copolymers mainly composed of structural units represented by the following general formulas (Q1) and (Q3) are exemplified. In addition to high proton conductivity, the aromatic polyetherketone-based polymer has good regularity, packing of polymer molecular chains, and high crystallinity or intermolecular cohesion. It has excellent mechanical properties such as solvent resistance such as tensile strength and elongation at break, tear strength and fatigue resistance, physical durability, and fuel barrier properties such as methanol and hydrogen. In addition, all benzene rings have high chemical stability, that is, radical resistance and oxidation resistance, because the electron density is low due to the influence of adjacent electron-withdrawing ketone groups. In addition, in this invention, a main component means containing 50 wt% or more with respect to superposition | polymerization of a polymer. Preferably, the structural units represented by the general formulas (Q1) and (Q3) are more preferably contained in an amount of 70 wt% or more, and most preferably 85 wt% or more.

(In the general formula (Q1) and (Q3), the a3 and a4 are integers satisfying the a3 + a4 = 2. Further, ^{M 3} and ^{M 4} are hydrogen, metal cation, an ammonium cation. General Formula (Q1) and ( The structural unit represented by Q3) may be optionally substituted except for an ionic group.
Among them, in the structural units represented by the general formulas (Q1) and (Q3), those having no substituent are more preferable in terms of crystallinity. In the general formulas (Q1) and (Q3), 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.

  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.

  The molecular weight of the ionic group-containing polymer of the present invention thus obtained is 10000 to 5 million, preferably 10,000 to 500,000 in terms of polystyrene-converted weight average molecular weight. If it is less than 10,000, any of the mechanical strength, physical durability, and solvent resistance may be insufficient, such as cracking in the molded film. On the other hand, if it exceeds 5,000,000, there are problems such as insufficient solubility, high solution viscosity, and poor processability.

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.

  The sulfonic acid 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 conveniently 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.

  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.

  The method for molding the polymer electrolyte material of the present invention into a membrane is not particularly limited, but in the stage having a protective group such as acetal and / or ketal, a method of forming a film from a solution state or a method of forming a film from a molten state, etc. 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 the polymer electrolyte material can be dissolved and then removed. For example, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone , Dimethyl sulfoxide, sulfolane, aprotic polar solvents such as 1,3-dimethyl-2-imidazolidinone and hexamethylphosphontriamide, ester solvents such as γ-butyrolactone and butyl acetate, carbonates such as ethylene carbonate and propylene carbonate Solvent, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, alkylene glycol monoalkyl ether such as propylene glycol monoethyl ether, or isopropanol Alcohol solvents, 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 obtained polymer electrolyte membrane 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 form and heat-treat as it is. The metal of the metal salt may be any metal that can form a salt with sulfonic acid, but from the viewpoint of cost and environmental load, 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 cutoff.

  As a method for converting the polymer electrolyte material used in the present invention into a membrane, at least a part of the ketone moiety protected with acetal and / or ketal after the membrane composed of the polymer electrolyte material is produced by the above-described method. Is deprotected to form a ketone moiety. According to this method, it is possible to form a solution film of a low sulfonic acid group polymer having poor solubility, and to achieve both proton conductivity and fuel barrier properties, excellent solvent resistance, mechanical strength, and physical durability. It becomes.

  In the polymer electrolyte membrane of the present invention, the polymer structure can be further cross-linked by means such as radiation irradiation as 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 film thickness of the polymer electrolyte membrane of the present invention is preferably 1 to 2000 μm. In order to obtain the mechanical strength and physical durability of the membrane that can withstand practical use, it is more preferably thicker than 1 μm, and in order to reduce membrane resistance, that is, improve power generation performance, it is preferably thinner than 2000 μm. 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.

  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. Moreover, you may reinforce with a microporous film, a nonwoven fabric, a mesh, etc.

  The membrane electrode composite obtained by the present invention means a membrane electrode composite containing the polymer electrolyte membrane of the present invention or 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.

  In the case of integration by heating press, the temperature and pressure may be appropriately selected depending on the thickness of the electrolyte membrane, the moisture content, the catalyst layer, and the electrode substrate. Further, in the present invention, it is possible to form a composite by pressing even when the electrolyte membrane is in a dry state or in a state of absorbing water. Specific pressing methods include a roll press that defines pressure and clearance, and a flat plate press that defines pressure. From the viewpoint of industrial productivity and suppression of thermal decomposition of a polymer material having an ionic group, it is 0. It is preferable to carry out in the range of from ℃ to 250 ℃. The pressurization is preferably as weak as possible from the viewpoint of electrolyte membrane and electrode protection. In the case of a flat plate press, a pressure of 10 MPa or less is preferable, and the electrode and the electrolyte membrane are stacked without carrying out the complexing by the hot press process. Cell formation is also one of the preferred options from the viewpoint of preventing short-circuiting of the anode and cathode electrodes. In the case of this method, when power generation is repeated as a fuel cell, the deterioration of the electrolyte membrane presumed to be caused by a short-circuited portion tends to be suppressed, and the durability as a fuel cell is improved.

  In addition, when heat-pressing above the softening temperature or glass transition temperature of the electrolyte material, it is difficult to employ a temperature above the softening temperature or glass transition temperature of the electrolyte material if the ionic group decomposition temperature is close. Decomposition can be suppressed by using a group as a metal salt, and heat pressing can be performed at a temperature above the softening temperature or glass transition temperature of the electrolyte material. For example, when the ionic group of the electrolyte material such as the binder in the electrode or the electrolyte membrane is a sulfonic acid group, the sulfonic acid Na is used, and after proton bonding with a hot press, proton exchange is performed with hydrochloric acid, sulfuric acid, etc. Manufacturing the body.

  It is also a preferable method that an interfacial resistance reducing layer is interposed between the electrode and the electrolyte membrane when the electrode and the electrolyte membrane are combined. These contact areas can be substantially increased by filling at least a part of the fine gap between the electrode and the electrolyte membrane with the interface resistance reducing layer, and fuel, air used as a fuel cell, and generation are generated in the gap. It is possible to prevent an increase in resistance due to entering water or carbon dioxide. In addition, the interfacial resistance-reducing composition penetrates into the cracks generated in the catalyst layer of the electrode, and the inner wall surface of the catalyst layer crack that could not be used for power generation can be used effectively. The area can be increased. As a result, the resistance of the membrane electrode assembly decreases, the power density increases, and a high-performance fuel cell can be obtained. Furthermore, it is also possible to cover the protrusions of the electrode base material and catalyst layer, etc., which can reduce the micro short-circuit during the production of the membrane electrode composite and the micro short-circuit in use as a fuel cell, thereby reducing the performance of the membrane electrode composite. The effect which can be suppressed can also be expected. Furthermore, even if the electrolyte membrane has pinholes, surface defects, etc., it can be protected and repaired by the interface resistance reducing layer, and the performance and durability of the membrane electrode assembly can be stabilized.

  This interface resistance reduction layer is not particularly limited as long as it has ion conductivity such as the electrolyte material of the present invention and has resistance to the fuel used, but from the viewpoint of strength and fuel resistance, it contains the polymer electrolyte material of the present invention. Is particularly preferred. For example, when compositing a membrane electrode, the composition containing the electrolyte material of the present invention, a solvent and a plasticizer is used as a precursor of the interface resistance reducing layer, and after the membrane electrode is composited, the solvent and the plasticizer are dried, extracted and washed. As a result, it is possible to obtain a high-performance membrane electrode composite that has a reduction in interfacial resistance, mechanical strength, and fuel resistance. At this time, the interface resistance reducing layer precursor may be formed on the electrode side or on the electrolyte membrane side before the composite step.

  Next, an example of an electrode suitable for the membrane electrode assembly of the present invention will be described. Such an electrode comprises a catalyst layer and an electrode substrate. The catalyst layer here is a layer containing a catalyst for promoting an electrode reaction, an electron conductor, an ion conductor, and the like. As the catalyst contained in the catalyst layer, for example, a noble metal catalyst such as platinum, palladium, ruthenium, rhodium, iridium, gold is preferably used. One of these may be used alone, or two or more of them, such as alloys and mixtures, may be used in combination.

  Moreover, when using an electronic conductor (conductive material) for a catalyst layer, a carbon material and an inorganic conductive material are preferably used from the point of electronic conductivity or chemical stability. Among these, amorphous and crystalline carbon materials are mentioned. For example, carbon black such as channel black, thermal black, furnace black, and acetylene black is preferably used because of its electron conductivity and specific surface area. As furnace black, Vulcan XC-72R (registered trademark), Vulcan P (registered trademark), Black Pearls 880 (registered trademark), Black Pearls 1100 (registered trademark), Black Pearls 1300 (registered trademark), Black Pearls manufactured by Cabot Corporation. 2000 (Registered Trademark), Legal 400 (Registered Trademark), Ketjen Black International Ketjen Black EC (Registered Trademark), EC600JD, Mitsubishi Chemical Corporation # 3150, # 3250, and the like. Examples include Denka Black (registered trademark) manufactured by Chemical Industries. In addition to carbon black, artificial graphite or carbon obtained from organic compounds such as natural graphite, pitch, coke, polyacrylonitrile, phenol resin, and furan resin can also be used. As the form of these carbon materials, in addition to irregular particles, fibers, scales, tubes, cones, and megaphones can also be used. Moreover, you may use what post-processed these carbon materials.

  Moreover, when using an electronic conductor, it is preferable from the point of electrode performance that it is disperse | distributing uniformly with a catalyst particle. For this reason, it is preferable that the catalyst particles and the electron conductor are well dispersed in advance as a coating liquid. Furthermore, it is also a preferred embodiment to use catalyst-supporting carbon or the like in which the catalyst and the electron conductor are integrated as the catalyst layer. By using this catalyst-supporting carbon, the utilization efficiency of the catalyst is improved, which can contribute to the improvement of battery performance and cost reduction. Here, even when catalyst-supported carbon is used for the catalyst layer, a conductive agent can be added to further increase the electron conductivity. As such a conductive agent, the above-described carbon black is preferably used.

  As the substance having ion conductivity (ion conductor) used in the catalyst layer, various organic and inorganic materials are generally known. However, when used in a fuel cell, sulfone which improves ion conductivity. A polymer having an ionic group such as an acid group, a carboxylic acid group, or a phosphoric acid group (ion conductive polymer) is preferably used. Among them, from the viewpoint of the stability of the ionic group, a polymer having ion conductivity composed of a fluoroalkyl ether side chain and a fluoroalkyl main chain, or the polymer electrolyte material of the present invention and a known hydrocarbon electrolyte Materials are preferably used. As the perfluoro-based ion conductive polymer, for example, Nafion (registered trademark) manufactured by DuPont, Aciplex (registered trademark) manufactured by Asahi Kasei Corporation, Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., and the like are preferably used. These ion conductive polymers are provided in the catalyst layer in a solution or dispersion state. At this time, the solvent for dissolving or dispersing the polymer is not particularly limited, but a polar solvent is preferable from the viewpoint of the solubility of the ion conductive polymer. Among these, the polymer electrolyte material of the present invention can be most suitably used as a substance (ion conductor) having ion conductivity in the catalyst layer. In particular, in the case of a fuel cell using methanol aqueous solution or methanol as fuel, the polymer electrolyte material of the present invention is effective for durability from the viewpoint of methanol resistance. The polymer electrolyte material of the present invention is processed at the soluble precursor polymer stage to form an MEA, and then deprotection is performed to provide solvent resistance, thereby providing a highly preferable binder that achieves both workability and solvent resistance. It is possible to produce.

  Since the catalyst and the electronic conductors are usually powders, the ionic conductor usually plays a role of solidifying them. It is preferable from the viewpoint of electrode performance that the ionic conductor is added in advance to a coating liquid containing catalyst particles and an electronic conductor as main constituents when the catalyst layer is prepared, and is applied in a uniformly dispersed state. is there. The amount of the ionic conductor contained in the catalyst layer should be appropriately determined according to the required electrode characteristics and the conductivity of the ionic conductor used, and is not particularly limited, but the weight ratio The range of 1 to 80% is preferable, and the range of 5 to 50% is more preferable. When the ion conductor is too small, the ion conductivity is low, and when it is too much, the gas permeability may be hindered.

  Such a catalyst layer may contain various substances in addition to the catalyst, the electron conductor, and the ionic conductor. In particular, in order to improve the binding property of the substance contained in the catalyst layer, a polymer other than the above-described ion conductive polymer may be included. Examples of such a polymer include fluorine atoms such as polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyhexafluoropropylene (FEP), polytetrafluoroethylene, and polyperfluoroalkyl vinyl ether (PFA). These copolymers, copolymers of monomer units constituting these polymers and other monomers such as ethylene and styrene, or blend polymers can be used. The content of these polymers in the catalyst layer is preferably in the range of 5 to 40% by weight. When there is too much polymer content, there exists a tendency for an electronic and ionic resistance to increase and for electrode performance to fall.

  In addition, when the fuel is a liquid or gas, the catalyst layer preferably has a structure in which the liquid or gas easily permeates, and preferably has a structure that promotes the discharge of by-products due to the electrode reaction.

  Moreover, as an electrode base material, an electrical resistance is low and what can collect or supply electric power can be used. Further, when the catalyst layer is used also as a current collector, it is not necessary to use an electrode substrate. Examples of the constituent material of the electrode base material include carbonaceous and conductive inorganic substances. For example, a fired body from polyacrylonitrile, a fired body from pitch, a carbon material such as graphite and expanded graphite, stainless steel, molybdenum And titanium. These forms are not particularly limited, and are used, for example, in the form of fibers or particles. From the viewpoint of fuel permeability, fibrous conductive materials (conductive fibers) such as carbon fibers are preferable. As an electrode base material using conductive fibers, either a woven fabric or a non-woven fabric structure can be used. For example, carbon paper TGP series, SO series manufactured by Toray Industries, Inc., carbon cloth manufactured by E-TEK, etc. are used. Examples of the woven fabric include plain weave, oblique weaving, satin weaving, crest weaving, binding weaving, and the like. Moreover, as a nonwoven fabric, it does not specifically limit, such as a paper making method, a needle punch method, a spun bond method, a water jet punch method, and a melt blow method. It may also be a knitted fabric. In particular, when carbon fibers are used in these fabrics, carbonized plain fabric using flame-resistant spun yarn is carbonized or graphitized, and flame-resistant yarn is carbonized after being processed into a nonwoven fabric by the needle punch method or water jet punch method. Alternatively, a graphitized nonwoven fabric, a flameproof yarn, a carbonized yarn, or a mat nonwoven fabric by a paper making method using a graphitized yarn is preferably used. In particular, it is preferable to use a nonwoven fabric or cloth from the viewpoint of obtaining a thin and strong fabric.

  Examples of the carbon fiber used for the electrode substrate include polyacrylonitrile (PAN) carbon fiber, phenolic carbon fiber, pitch carbon fiber, and rayon carbon fiber.

  In addition, the electrode base material has a water repellent treatment for preventing gas diffusion / permeability deterioration due to water retention, a partial water repellent treatment for forming a water discharge path, a hydrophilic treatment, and a resistance reduction. For example, carbon powder can be added. Further, a conductive intermediate layer containing at least an inorganic conductive substance and a hydrophobic polymer can be provided between the electrode substrate and the catalyst layer. In particular, when the electrode base material is a carbon fiber woven fabric or a nonwoven fabric having a large porosity, by providing the conductive intermediate layer, it is possible to suppress performance degradation due to the catalyst layer soaking into the electrode base material.

  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. When an aqueous methanol solution is used, the concentration of methanol is appropriately selected depending on the fuel cell system to be used. 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 concentration of methanol 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. A passive fuel cell without auxiliary equipment has a methanol concentration Is preferable in the range of 10 to 100%.

  Furthermore, the application of the polymer electrolyte fuel cell using the polymer electrolyte material and the polymer electrolyte membrane of the present invention is not particularly limited, but a power supply source for a mobile 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 a membrane sample in pure water at 25 ° C. for 24 hours, the membrane sample is taken out in an atmosphere at 25 ° C. and a relative humidity of 50 to 80%, and the proton conductivity is measured by the constant potential AC impedance method as quickly as possible. did.

As a measuring apparatus, a Solartron electrochemical measurement system (Solartron 1287 Electrochemical Interface and Solartron 1255B Frequency Response Analyzer) was used. The sample was sandwiched between two circular electrodes (made of stainless steel) of φ2 mm and φ10 mm with a weight of 1 kg. The effective electrode area is 0.0314 cm ² . A 15% aqueous solution of poly (2-acrylamido-2-methylpropanesulfonic acid) was applied to the interface between the sample and the electrode. At 25 ° C., a constant potential impedance measurement with an AC amplitude of 50 mV was performed to determine proton conductivity in the film thickness direction.

(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 lithium bromide) at a sample concentration of 0.1 wt%, a flow rate of 0.2 mL / min, and a temperature of 40 ° C. The weight average molecular weight was determined.

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

(5) Methanol permeation amount A membrane-shaped sample was immersed in pure water at 25 ° C for 24 hours, and then measured at 20 ° C using a 1 mol% aqueous methanol solution.

A sample membrane was sandwiched between the H-type cells, and pure water (60 mL) was placed in one cell, and 1 mol% aqueous methanol solution (60 mL) was placed in the other cell. The cell capacity was 80 mL each. Moreover, the opening area between cells was 1.77 cm < ² >. Both cells were stirred at 20 ° C. The amount of methanol eluted in pure water at the time of 1 hour, 2 hours and 3 hours was measured and quantified with a gas chromatography (GC-2010) manufactured by Shimadzu Corporation. The methanol permeation amount per unit time was determined from the slope of the graph.

(6) Confirmation of presence or absence of crystallization peak and crystallization calorimetry Preliminarily drying the polymer electrolyte material (3.5 to 4.5 mg) as a specimen at a temperature at which the sulfonic acid group does not decompose (for example, 40 to 100 ° C.) After removing the moisture, the weight is measured. At this time, since the chemical structure or higher order structure of the polymer may change, the temperature is not raised above the crystallization temperature or the thermal decomposition temperature. After measuring the weight, the polymer electrolyte material was subjected to temperature modulation differential scanning calorimetry at the first temperature raising stage under the following conditions.

DSC apparatus: DSC Q100 manufactured by TA Instruments
Measurement temperature range: 25 ° C. to thermal decomposition temperature (eg, 310 ° C.)
Temperature increase rate: 5 ° C / min Amplitude: ± 0.796 ° C
Sample amount: about 4mg
Sample pan: Aluminum crimp pan Measurement atmosphere: Nitrogen 50 ml / min
Pre-drying: Vacuum drying 60 ° C., 1 hour A value obtained by doubling the amount of heat from the low temperature side to the peak top was calculated as the amount of crystallization heat. Further, since the specimen contained water, the water content was calculated from the detected heat of evaporation of water, and the weight of the polymer electrolyte material was corrected. The evaporation heat of water is 2277 J / g.

Weight of water in sample (g) = heat of evaporation of sample water (J / g) × sample amount (g) / 2277 (J / g)
Crystallization calorific value correction value (J / g) = crystallization calorific value (J / g) × sample amount (g) / (sample amount−weight of water in sample (g))
(7) Wide-angle X-ray diffraction The polymer electrolyte material used as a specimen was set in a diffractometer, and X-ray diffraction measurement was performed under the following conditions.

X-ray diffractometer: RINT2500V manufactured by Rigaku Corporation
X-ray: Cu-Kα
X-ray output: 50kV-300mA
Optical system: Concentrated optical system Scan speed: 2θ = 2 ° / min
Scanning method: 2θ-θ
Scan range: 2θ = 5-60 °
Slit: Divergence slit -1 / 2 °, Light receiving slit -0.15mm, Scattering slit -1 / 2 °
The degree of crystallinity is obtained by separating each component by profile fitting, obtaining the diffraction angle and integrated intensity of each component, and using the obtained crystalline peak and the integrated intensity of the amorphous halo, the general formula (S2) The crystallinity was calculated from the following formula.

Crystallinity (%) = (sum of integrated intensities of all crystalline peaks) / (sum of integrated intensities of all crystalline peaks and amorphous halo) × 100 (S2)
(8) Measurement of Elmendorf Tear Strength The polymer electrolyte membrane as a specimen was allowed to stand at 25 ° C. and 50% RH for 24 hours, then set in an apparatus, and Elmendorf tear strength was measured under the following conditions.

Measuring device: Elmendorf Tear Tester (Toyo Seiki)
Test load: FS = 100g
Test piece: width 63mm x length 76mm
Test temperature: 25 ° C., 50% RH
Number of tests: n = 5
Number of layers: 1 The Elmendorf tear strength was calculated as an average value of 5 tests. Moreover, in order to remove the influence of the film thickness, it was expressed as the tear strength per unit film thickness. When there is anisotropy in the tear strength of the film, measurement is performed in two orthogonal directions, and the average value is taken as the tear strength. For the film of this example, no anisotropy was observed, so data in only one direction was shown.

(9) Tensile strength / elongation measurement The polymer electrolyte membrane used as a specimen was allowed to stand at 25 ° C. and 60% RH for 24 hours, then set in an apparatus, and measured for tensile strength / elongation under the following conditions. The tensile strength / elongation was calculated as an average value of five test times.

Measuring device: SV-201 type tensile and compression testing machine (manufactured by Imada Seisakusho)
Load: 50N
Tensile speed: 10 mm / min
Test piece: width 5 mm x length 50 mm
Distance between samples: 20mm
Test temperature: 25 ° C., 60% RH
Number of tests: n = 5
(10) Weight reduction with respect to N-methylpyrrolidone A polymer electrolyte membrane (about 0.1 g) as a specimen was sufficiently washed with pure water, and then vacuum-dried at 40 ° C. for 24 hours to measure the weight. The polymer electrolyte membrane was immersed in 1000 times the weight of N-methylpyrrolidone and heated in an airtight container at 100 ° C. for 2 hours with stirring. Next, filtration was performed using filter paper (No. 2) manufactured by Advantech. At the time of filtration, the filter paper and the residue were washed with 1000 times weight of the same solvent, the eluate was sufficiently eluted in the solvent, and the N-methylpyrrolidone contained in the residue was sufficiently washed with pure water. The residue was vacuum-dried at 40 ° C. for 24 hours and the weight was measured to calculate the weight loss.

(11) Analysis of residual amount of ketal group The sample polymer electrolyte material was subjected to gas analysis during heating under the following conditions to find C ₂ H ₄ O (m / z = 29) and 2-methyl-1 , 3-Dioxolane (m / z = 73) was quantified for the remaining amount of ketal group (wt%).
(A) Equipment used
TPD-MS equipment <Main specifications>
Heating unit: TRC heating device (electric heater type heating furnace, quartz glass reaction tube)
MS Department: Shimadzu GC / MS QP5050A
(B) Test conditions Heating temperature condition: Room temperature to 550 ° C (Temperature increase rate 10 ° C / min)
Atmosphere: He flow (50mL / min) (Iwatani Corp., purity 99.995%)
(C) Sample Amount of sample used: Approximately 1.5 mg
Pretreatment: Vacuum drying at 80 ° C for 180 minutes (D) Standard product Tank sodium stearate dihydrate (H ₂ O standard sample): Sigma Aldrich, special grade 99%
1-butene (organic component standard sample): GL science, 7.92% / N ₂ balance Carbon dioxide: GL science, 99.9%
Sulfur dioxide: Sumitomo Seika, 1.000% / N ₂ balance Phenol: Wako Pure Chemicals, special grade 99.0%
2-methyl-1,3-dioxolane (C ₂ H ₄ O, etc. and 2-methyl-1,3-dioxolane standard sample): Tokyo Chemical Industry, special grade 98%
(E) Measurement room temperature (room temperature range)
23 ± 2 ℃
(12) Nuclear magnetic resonance spectrum (NMR)
In the following measuring ^conditions, was measured for 1 H-NMR, subject to quantitative structural confirmation and 4,4'-dihydroxybenzophenone and 2,2-bis (4-hydroxyphenyl) -1,3-mixing ratio of dioxolane It was. The mixing ratio (mol%) is a peak observed at 7.6 ppm (derived from 4,4′-dihydroxybenzophenone) and 7.2 ppm (derived from 2,2-bis (4-hydroxyphenyl) -1,3-dioxolane). Calculated from the integrated value.

Apparatus: EX-270 manufactured by JEOL Ltd.
Resonance frequency: 270 MHz ( ¹ H-NMR)
Measurement temperature: room temperature Dissolving solvent: DMSO-d6
Internal reference material: TMS (0 ppm)
Accumulation count: 16 times Further, solid ¹³ C-CP / MAS spectrum was measured under the following measurement conditions, and the presence or absence of a ketal group was confirmed.

Apparatus: CMX-300 Infinity manufactured by Chemagnetics
Measurement temperature: Room temperature Internal reference material: Si rubber (1.56ppm)
Measurement nucleus: 75.188829 MHz
Pulse width: 90 ° pulse, 4.5 μsec
Pulse repetition time: ACQTM = 0.03413sec, PD = 9sec
Spectrum width: 30.003 kHz
Sample rotation: 7 kHz
Contact time: 4msec
(13) Performance evaluation of membrane electrode composite Voltage holding ratio The membrane electrode assembly was incorporated into an electrochem single cell “EFC05-01SP” (cell for electrode area 5 cm ² ), the cell temperature was set to 50 ° C., and 20% methanol aqueous solution 0.2 ml / min on the anode side Measure the voltage-current characteristics using a Toyo Technica evaluation device, a potentiostat 1470 made by solartron, and a frequency response analyzer made by solartron 1255B. Then, a voltage having a current density of 250 mA / cm ² was read, and thereafter, operation was stopped for 100 hours at a constant current of 250 mA / cm ^{2 in} a pattern in which power generation was stopped every 5 hours for 1 hour. After the constant current evaluation, a voltage with a current density of 250 mA / cm ² was read from the current-voltage curve, and the retention rate from the first time was calculated.
B. Measurement of fuel (methanol) permeation amount (hereinafter sometimes referred to as “MCO”) Before applying an electric current, the synthetic air discharged from the cathode is collected in a gas collection bag, and GE Using a gas chromatograph “MicroGC CP4900” with an autosampler manufactured by Science, the concentrations of both methanol in the sampling gas and carbon dioxide produced by oxidation were measured and calculated. Here, it was assumed that all carbon dioxide was generated from permeated methanol. The cathode air flow rate is L (ml / min), the total concentration of methanol and carbon dioxide by gas chromatography is Z (% by volume), the total volume is V (ml), and the open area (the aqueous methanol fuel in the membrane electrode assembly is The area of direct contact) was A (cm ² ), and the following formula was used for calculation.

MCO (mol / cm ² / min) = (L + V) × (Z / 100) / 22400 / A
C. Power generation evaluation (methanol water fuel)
In a state where 30% by weight methanol water was stored in the anode, measurement was performed using an evaluation apparatus manufactured by Toyo Technica, a potentiostat 1470 manufactured by solartron, and a frequency response analyzer 1255B manufactured by solartron. The current sweep rate was 10 mV / min, and the voltage was measured up to 30 mV. A value obtained by dividing the point at which the product of the current and voltage in the current-voltage curve becomes the highest by the electrode area was taken as the output density.
D. Power generation evaluation (hydrogen fuel)
Fuel cell: cell temperature: 60 ° C., fuel gas: hydrogen, oxidizing gas: air, gas utilization: anode 70% / cathode 40%, humidification; anode-90% / cathode 90% current-voltage (IV) )It was measured. A value obtained by dividing the point at which the product of the current and voltage in the current-voltage curve becomes the highest by the electrode area was taken as the output density.

Synthesis example 1
Synthesis of 2,2-bis (4-hydroxyphenyl) -1,3-dioxolane (K-DHBP) represented by the following general formula (G1)

  4,3′-dihydroxybenzophenone (495 g, DHBP, Tokyo Kasei Reagent) and Montmorillonite clay K10 (750 g, Aldrich Reagent) were placed in a 3 L flask equipped with a Teflon (registered trademark) stirring blade and thermometer, and after nitrogen substitution And ethylene glycol (1200 mL, Wako Pure Chemical Reagent) / trimethyl orthoformate (500 mL, Wako Pure Chemical Reagent) were added. While stirring, at a bath temperature of 110 ° C./inner temperature of 74 ° C./steam temperature of 52 ° C., methanol and methyl formate were reacted together with trimethyl orthoformate for 8 hours while gradually distilling. Next, 500 mL of trimethyl orthoformate was added, and the mixture was further reacted for 8 hours.

After dilution with 1 L of ethyl acetate, the clay was removed by filtration, and a washing solution of ethyl acetate 500 mL × 3 was also added. Extraction was performed 4 times with 1 L of 2% NaHCO ₃ aqueous solution and once with 1 L of saturated brine, dehydrated with Na ₂ SO ₄ and concentrated. Dichloromethane (500 mL) was added to the obtained white slurry solution, and filtration and washing with dichloromethane (250 mL × 3) were performed to obtain the target K-DHBP / DHBP mixture as a pale yellow solid (yield: 347 g, K-DHBP / DHBP = 94/6 (mol%)). The structure was confirmed by ¹ H-NMR, and the ratio of K-DHBP / DHBP was calculated. Other impurities were not observed by gas chromatography.

Synthesis example 2
Synthesis of disodium 3,3′-disulfonate-4,4′-difluorobenzophenone represented by the following general formula (G2)

109.1 g (Aldrich reagent) of 4,4′-difluorobenzophenone was reacted at 100 ° C. for 10 hours in 150 mL of fuming sulfuric acid (50% 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).

Example 1
Synthesis of a polymer represented by the following general formula (G3)

(In the formula, * represents that the right end of the above formula and the left end of the below formula are bonded at that position. The sulfonic acid group is described in Na type, but was substituted with K type during polymerization. (All bisphenol residues are listed as K-DHBP residues, but include DHBP residues.)
In a 500 mL three-necked flask equipped with a stirrer, a nitrogen introduction tube, and a Dean-Stark trap, 13.82 g of potassium carbonate (Aldrich reagent, 100 mmol), K-DHBP / DHBP obtained in Synthesis Example 1 = 94/6 (mol%) ) 20.4 g (80 mmol) of the mixture, 12.2 g of 4,4′-difluorobenzophenone (Aldrich reagent, 56 mmol), and disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 10.1 g (24 mmol) was added, and after nitrogen substitution, dehydration was performed at 180 ° C. in 90 mL of N-methylpyrrolidone (NMP) and 45 mL of toluene, and then the temperature was raised to remove toluene, and polymerization was performed at 230 ° C. for 10 hours. Purification was performed by reprecipitation with a large amount of water to obtain a polyketal ketone represented by the general formula (G3). The weight average molecular weight was 350,000.

  The obtained 25 wt% N-methylpyrrolidone (NMP) solution in which the polyketal ketone of the general formula (G3) was dissolved was subjected to pressure filtration using a glass fiber filter, and then cast onto a glass substrate and applied at 100 ° C. And dried for 2 hours at 300 ° C. under nitrogen for 30 minutes and heat-treated at 300 ° C. for 10 minutes to obtain a polyketal ketone film. The solubility of the polymer was very good. After being immersed in 6N hydrochloric acid at 95 ° C. for 24 hours for proton substitution and deprotection, it was immersed in a large excess of pure water for 24 hours and washed sufficiently to obtain a polymer electrolyte membrane.

  The evaluation results are summarized in Table 1. In the obtained polymer electrolyte membrane, a crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. It was an extremely tough electrolyte membrane. Excellent solvent resistance. Furthermore, while maintaining conductivity, it was excellent in fuel cutoff. Moreover, even if it was immersed in hot water or hot methanol, it was a tough film without dissolving or disintegrating, and was extremely excellent in hot water resistance and hot methanol resistance.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

The polyketal ketone represented by the above general formula (G3) was subjected to quantitative analysis of the ketal group-derived substance by TPD-MS measurement. As a result, C ₂ H ₄ O was 5.22 w% per 250 ° C., 2- Methyl-1,3-dioxolane was 0.39 wt%, and a total of 5.61 wt% of ketal group-derived substances were detected.

Example 2
Charge amount of 12.4 g (Aldrich reagent, 56 mmol) of 4,4′-difluorobenzophenone and 10.1 g (24 mmol) of disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 A polyketal ketone polymer and a polymer electrolyte membrane were prepared by the method described in Example 1 except that the amount was changed to 11.3 g (52 mmol) and 11.8 g (28 mmol), respectively. The weight average molecular weight of the polyketal ketone polymer was 330,000.

  The evaluation results are summarized in Table 1. In the obtained polymer electrolyte membrane, a crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. It was an extremely tough electrolyte membrane. Excellent solvent resistance. Furthermore, while maintaining conductivity, it was excellent in fuel cutoff.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 3
Charge of 12.2 g of 4,4′-difluorobenzophenone (Aldrich reagent, 56 mmol) and 10.1 g (24 mmol) of disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 A polyketal ketone polymer and a polymer electrolyte membrane were prepared by the method described in Example 1, except that 1 was changed to 10.5 g (48 mmol) and 13.5 g (32 mmol), respectively. The weight average molecular weight of the polyketal ketone polymer was 280,000.

  The evaluation results are summarized in Table 1. In the obtained polymer electrolyte membrane, a crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. It was an extremely tough electrolyte membrane. Excellent solvent resistance. Furthermore, while maintaining conductivity, it was excellent in fuel cutoff.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 4
In Example 1, a polymer electrolyte membrane was prepared by the method described in Example 1 except that the clearance when cast-coated on a glass substrate was changed thinly and the thickness of the electrolyte membrane was changed thinly.

  The evaluation results are summarized in Table 2. The obtained polymer electrolyte membrane was excellent in tear strength, tensile rupture strength, and tensile rupture elongation, and was an extremely tough electrolyte membrane. Furthermore, the conductivity was also excellent.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 5
In Example 2, a polymer electrolyte membrane was prepared by the method described in Example 2 except that the clearance at the time of casting application on a glass substrate was changed thinly and the thickness of the electrolyte membrane was changed thinly.

  The evaluation results are summarized in Table 2. The obtained polymer electrolyte membrane was excellent in tear strength, tensile rupture strength, and tensile rupture elongation, and was an extremely tough electrolyte membrane. Excellent solvent resistance. Furthermore, the conductivity was also excellent.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 6
In Example 3, a polymer electrolyte membrane was produced by the method described in Example 3 except that the clearance when cast-coated on a glass substrate was changed thinly and the thickness of the electrolyte membrane was changed thinly.

  The evaluation results are summarized in Table 2. The obtained polymer electrolyte membrane was excellent in tear strength, tensile rupture strength, and tensile rupture elongation, and was an extremely tough electrolyte membrane. Furthermore, the conductivity was also excellent.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 7
Charge of 12.2 g of 4,4′-difluorobenzophenone (Aldrich reagent, 56 mmol) and 10.1 g (24 mmol) of disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 A polyketal ketone polymer and a polymer electrolyte membrane were prepared by the method described in Example 1 except that was changed to 9.6 g (44 mmol) and 15.2 g (36 mmol), respectively. The weight average molecular weight of the polyketal ketone polymer was 250,000.

  The evaluation results are summarized in Table 3. In the obtained polymer electrolyte membrane, a crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. The electrolyte membrane was excellent in tear strength, tensile rupture strength, and tensile rupture elongation, and was an extremely tough electrolyte membrane. The solvent resistance was also relatively excellent. Furthermore, the conductivity was also excellent.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shifts of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Example 8
Charge of 12.2 g of 4,4′-difluorobenzophenone (Aldrich reagent, 56 mmol) and 10.1 g (24 mmol) of disodium 3,3′-disulfonate-4,4′-difluorobenzophenone obtained in Synthesis Example 2 A polyketal ketone polymer and a polymer electrolyte membrane were prepared by the method described in Example 1 except that γ was changed to 8.7 g (40 mmol) and 13.5 g (40 mmol), respectively. The weight average molecular weight of the polyketal ketone polymer was 240,000.

  The evaluation results are summarized in Table 3. In the obtained polymer electrolyte membrane, a crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. The electrolyte membrane was excellent in tear strength, tensile rupture strength, and tensile rupture elongation, and was an extremely tough electrolyte membrane. Excellent solvent resistance. Furthermore, the conductivity was also excellent.

Further, in the solid ¹³ C-CP / MAS spectrum, peaks of chemical shift of about 65 ppm and about 110 ppm (derived from ketal group) observed in the polyketal ketone film before deprotection are observed in the polymer electrolyte membrane after deprotection. I was not able to admit. Therefore, the deprotection reaction proceeded at a high conversion rate.

Comparative Example 1
Various properties were evaluated using a commercially available Nafion (registered trademark) 117 membrane (manufactured by DuPont). The Nafion (registered trademark) 117 membrane was immersed in 5% hydrogen peroxide water at 100 ° C. for 30 minutes, then in 5% dilute sulfuric acid at 100 ° C. for 30 minutes, and then thoroughly washed with deionized water at 100 ° C. .

  The evaluation results are summarized in Table 4. In the obtained polymer electrolyte membrane, no crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. The tear strength was low and the tensile elongation at break was excellent, but the tensile strength at break was poor. Furthermore, although the conductivity was high, the fuel shut-off property was inferior.

Comparative Example 2
Various properties were evaluated using a commercially available Nafion (registered trademark) 111 membrane (manufactured by DuPont). 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 evaluation results are summarized in Table 4. In the obtained polymer electrolyte membrane, no crystallization peak was observed in DSC (first heating stage). Further, no crystalline peak was observed by wide-angle X-ray diffraction. The tear strength was low and the tensile elongation at break was excellent, but the tensile strength at break was poor. Furthermore, although the conductivity was high, the fuel shut-off property was inferior.

Comparative Example 3
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. Since the polymer is sulfonated while being dissolved, it is difficult to obtain the position and amount of the sulfonic acid group with good reproducibility.

  A 25 wt% N-methylpyrrolidone (NMP) solution in which the resulting sulfonated product was dissolved was subjected to pressure filtration using a glass fiber filter, and then cast on a glass substrate, dried at 100 ° C. for 4 hours, Got. 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 evaluation results are summarized in Table 4. In the obtained polymer electrolyte membrane, no crystallization peak was observed by DSC (first heating stage), and no crystalline peak was observed by wide-angle X-ray diffraction. Furthermore, the conductivity was relatively high, but the fuel shut-off property was inferior. Moreover, since it collapse | disintegrated in 60 degreeC and 30 wt% methanol aqueous solution or 95 degreeC hot water, it was inferior to hot water resistance or heat resistant methanol property. Moreover, it was inferior also to solvent resistance. Although the tensile elongation at break was relatively large, the tensile break strength and tear strength were small.

Comparative Example 4
PEK was sulfonated.

  10 g of a polyetherketone resin (Victorex (registered trademark) PEEK-HT (manufactured by Victorex)) 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 1, but poor in solubility. Further, the presence of a ketal group could not be confirmed from IR and solid ¹³ C-CP / MAS spectrum. Various evaluations could not be performed. In the obtained polymer, no crystallization peak was observed in DSC (first heating stage).

  The powdered polyetherketone resin showed a crystalline peak by wide-angle X-ray diffraction, and the crystallinity was 30%. No crystallization peak was observed in DSC (first heating stage).

Comparative Example 5
The method described in Example 3 except that the amount of 20.4 g (80 mmol) of the K-DHBP / DHBP = 94/6 (mol%) mixture obtained in Synthesis Example 1 was changed to 17.1 g (80 mmol) of DHBP. Polymerization of polyetherketone polymer 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.

  Each evaluation result of Examples 1-8 and Comparative Examples 1-5 is shown in Tables 1-4. The polymer electrolyte membranes of Examples 1 to 3 were observed to have a crystallization peak, excellent in proton conductivity, excellent in fuel blocking properties, solvent resistance, and the like. The polymer electrolyte membranes of Examples 4 to 6 were excellent in tear strength, tensile break strength, and tensile break elongation. The polymer electrolyte membranes of Examples 7 and 8 have a crystallization peak, excellent proton conductivity, and excellent fuel cutoff, solvent resistance, tear strength, tensile rupture strength, tensile rupture elongation, and the like. It was. The electrolyte membrane of the comparative example was remarkably inferior in any of the characteristics.

Electrode production example 1
(1) Electrode for membrane electrode assembly using methanol aqueous solution as fuel On the carbon cloth “TL-1400W” made of carbon fiber fabric made by E-TEK in the United States, Pt− made by Johnson Matthey (Johson & Matthey) Ru-supported carbon catalyst “HiSPEC” (registered trademark) 10000 and “HiSPEC” (registered trademark) 6000, anode catalyst coating comprising the polyketal ketone of formula (G3) obtained in Example 1 and N-methyl-2-pyrrolidone The solution was applied and dried to prepare an electrode A. The anode catalyst coating solution was applied to the surface coated with the carbon black dispersion. Similarly, on the above electrode base material, Tanaka Kikinzoku Kogyo Co., Ltd. Pt-supported carbon catalyst TEC10V50E, DuPont 20% "Nafion" (registered trademark) solution and n-propanol The cathode catalyst coating solution was applied and dried to prepare an electrode B.

The catalyst adhesion amount was adjusted so that the electrode A was 2.5 mg / cm ² in terms of platinum weight, and the electrode B was 4.5 mg / cm ^{2 in} terms of platinum weight.

(2) Electrode for membrane electrode assembly using hydrogen as fuel
Aldrich “Nafion” (registered trademark) solution is loaded with catalyst-supported carbon (catalyst: Pt, carbon: Cabot ValcanXC-72, platinum loading: 50% by weight) with platinum and “Nafion” (registered trademark) weight The catalyst-polymer composition was prepared by adding to a ratio of 1: 0.5 and stirring well. This catalyst-polymer composition was applied to an electrode base material (carbon paper TGP-H-060 manufactured by Toray Industries, Inc.) that had been subjected to a water-repellent treatment (impregnated with 20% by weight of PTFE and calcined) and immediately dried. Thus, an electrode C was produced. The electrode adhesion amount of the electrode C was adjusted so as to be 1.0 mg / cm ^{2 in} terms of platinum weight.

Example of Preparation of Interfacial Resistance Reduction Layer Precursor 10 g of polyketal ketone of formula (G3) obtained in Example 1, 55 g of N-methyl-2-pyrrolidone and 45 g of glycerin are placed in a container and heated to 100 ° C. to be uniform. It stirred until it became it, and it was set as the interface resistance reduction layer precursor B.

Example 9
Using two electrodes C, the electrolyte membrane obtained in Example 6 was sandwiched so as to face each other, and heated and pressed at 130 ° C. for 10 minutes at a pressure of 5 MPa to obtain a membrane electrode assembly. This was incorporated into a power generation cell to obtain a fuel cell.

When the power generation characteristics of this fuel cell using hydrogen as a fuel were evaluated, the maximum output was 610 mW / cm ² .

Example 10
The film before deprotection obtained in Example 6 was sandwiched between the electrodes A and B so as to face each other, and bonded by performing a heat press at 200 ° C. for 1 minute at a pressure of 3 MPa. Next, the joined body was immersed in 100 g of 6N hydrochloric acid, heated to 80 ° C., and treated for 24 hours to obtain a membrane electrode composite. After that, it was washed with pure water until the washing solution became neutral, and incorporated into a power generation cell to obtain a fuel cell.

  The voltage holding ratio was 95% (the initial voltage was 0.25 V, the voltage after 100 hours constant current power generation was 0.24 V), and excellent durability was exhibited.

Further, the methanol permeation amount of this membrane electrode assembly was 4.6 μmol / cm ² / min. Moreover, the output in passive evaluation showed 41 mW / cm < ² >.

Comparative Example 6
A commercially available Nafion (registered trademark) solution (aldrich reagent) was applied to electrodes A and B and dried at 100 ° C. to obtain an electrode with a Nafion (registered trademark) coating. Using “Nafion 117 (registered trademark)” manufactured by DuPont as an electrolyte membrane, the above-mentioned electrodes were laminated so as to sandwich the electrolyte membrane without using the interface resistance reducing composition, and the pressure was 5 MPa at 130 ° C. for 30 minutes. Heat pressing was performed under pressure to obtain a membrane electrode assembly.

The membrane electrode composite has a large methanol permeation amount of 13.0 μmol / cm ² / min and a voltage holding ratio of 48% (the initial voltage is 0.21 V and the voltage after 100 hours of constant current power generation is 0.1 V). And the durability was inferior. Moreover, the output in passive evaluation was 10 mW / cm < ² > and was a low output. When the evaluation cell after these evaluations was disassembled, the membrane electrode assembly was taken out and visually observed, peeling due to swelling of the methanol aqueous solution occurred at the interface between the anode electrode and the electrolyte membrane, and part of the catalyst collapsed and flowed out. Was. The electrolyte material used had insufficient heat-resistant methanol resistance.

Example 11
The interface resistance reducing layer precursor B was applied on the electrodes A and B so as to be 3 mg / cm ^2, and heat-treated at 100 ° C. for 1 minute. These electrodes were cut so that the electrode projection area was 5 cm ² .

  Next, these electrodes with the interface resistance reducing layer precursor B are laminated so that the interface resistance reducing layer precursor B is on the film side before the deprotection treatment obtained in Example 6, and at 100 ° C. for 1 minute. Heat pressing was performed at a pressure of 3 MPa, and the pressed joined body was immersed in a solution obtained by adding 10 g of methanol to 90 g of 6N hydrochloric acid, heated to 80 ° C., and treated for 30 hours while refluxing to obtain a membrane electrode assembly. (Residual solvent extraction and proton exchange). After that, it was washed with pure water until the washing solution became neutral, and incorporated into a power generation cell to obtain a fuel cell.

  The voltage holding ratio was 95% (the initial voltage was 0.25 V, the voltage after 100 hours constant current power generation was 0.24 V), and excellent durability was exhibited.

Further, the methanol permeation amount of this membrane electrode assembly was 4.6 μmol / cm ² / min. Moreover, the output in passive evaluation showed 43 mW / cm < ² >.

Example 12
The membrane composite electrode body of Example 11 was manufactured to have an electrode area of 32 cm ^2, and a stack cell as shown in FIG. 1 was used to manufacture a fuel cell with six membrane electrode assemblies. When power was generated while circulating a 10% aqueous methanol solution on the anode side with a pump, an output of 7 W was obtained.

  The polymer electrolyte material and polymer electrolyte membrane of the present invention can be applied to various electrochemical devices (for example, fuel cells, water electrolysis devices, chloroalkali electrolysis devices, etc.). Among these devices, it is suitable for a fuel cell, and particularly suitable for a fuel cell using hydrogen or a methanol aqueous solution as fuel.

  The use of the polymer electrolyte fuel cell of the present invention is not particularly limited, but mobile devices such as mobile phones, personal computers, PDAs, video cameras, digital cameras, home appliances such as cordless vacuum cleaners, toys, electric bicycles, automatic It is preferably used as a power supply source for vehicles such as motorcycles, automobiles, buses, trucks, etc., moving bodies such as ships, railways, etc., conventional primary batteries such as stationary generators, alternatives to secondary batteries, or hybrid power sources with these. .

It is the figure which showed an example of the stacked fuel cell.

Explanation of symbols

1: Membrane electrode composite 2: Gasket 3: Bipolar separator 4: Current collector plate 5: Fuel supply port 6: Clamping screw 7: Air flow path 8: Fuel flow path 9: Fuel tank

Claims (17)

A polymer electrolyte material comprising an ionic group-containing polymer in which a crystallization peak is recognized by differential scanning calorimetry. 2. The polymer electrolyte material according to claim 1, wherein the crystallization calorific value measured by differential scanning calorimetry is 2 J / g or more. The polymer electrolyte material according to claim 1 or 2, wherein the degree of crystallinity measured by wide-angle X-ray diffraction is less than 0.5%. A polymer electrolyte component comprising the polymer electrolyte material according to claim 1. A polymer electrolyte membrane comprising the polymer electrolyte material according to claim 1. A polymer electrolyte membrane comprising an ionic group-containing polymer, wherein the Elmendorf tear strength in an atmosphere of 23 ° C and 50% relative humidity is 45 N / cm or more and 1000 N / cm or less . A polymer electrolyte membrane made of an ionic group-containing polymer having a tensile strength at break of 80 MPa to 1000 MPa and an elongation at break of 100% to 1000% in an atmosphere of 25 ° C. and a relative humidity of 60% A polymer electrolyte membrane characterized by that. The polymer electrolyte membrane according to claim 6 or 7, which has a tensile elastic modulus of 0.8 GPa or more and 5 GPa or less in an atmosphere of 25 ° C and a relative humidity of 60%. The polymer electrolyte membrane according to any one of claims 6 to 8, which has a tensile yield point strength of 30 MPa to 300 MPa in an atmosphere of 25 ° C and a relative humidity of 60%. The polymer electrolyte membrane according to any one of claims 5 to 9, wherein a weight loss after immersion in N-methylpyrrolidone at 100 ° C for 2 hours is 70% by weight or less. The polymer electrolyte membrane according to any one of claims 5 to 10, wherein the ionic group-containing polymer is a hydrocarbon polymer. 6. The polymer electrolyte material comprising an ionic group-containing polymer having a protective group is molded into a film shape, and then at least a part of the protective group of the molded polymer electrolyte membrane is deprotected. To 10. The polymer electrolyte membrane according to any one of 10 to 10. The polymer electrolyte membrane according to any one of claims 5 to 10, wherein the ionic group-containing polymer is an aromatic polyether ketone polymer. The polymer electrolyte membrane according to claim 5, wherein the ionic group is a sulfonic acid group. The polymer electrolyte according to any one of claims 5 to 11, wherein the aromatic polyetherketone-based polymer contains, as a main component, structural units represented by the following general formulas (Q1) and (Q3). film.

In (formula (Q3), the a3 and a4 are integers satisfying the a3 + a4 = 2. Also, tables in ^{M 3} and ^{M 4} are hydrogen, metal cation, an ammonium cation. General Formula (Q1) and (Q3) The structural unit may be optionally substituted except for the ionic group.) A membrane electrode assembly comprising the polymer electrolyte membrane according to any one of claims 5 to 14. A polymer electrolyte fuel cell comprising the membrane electrode assembly according to claim 16.

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