JP4447007B2 - Polymer electrolyte composition containing aromatic hydrocarbon resin - Google Patents

Abstract

A polyelectrolyte composition having high durability even under high-temperature low-level-humidification conditions (e.g., operating temperature of 100{C and 50{C humidification (corresponding to a humidity of 12 RH)); and a proton-exchange membrane comprising this polyelectrolyte composition. The polyelectrolyte composition comprises a polymer (A) having an ion-exchange group, a polyphenylene sulfide resin (B), and a polyphenylene ether resin (C) and/or a polysulfone resin (D).

Description

  The present invention relates to a polymer electrolyte composition and a proton exchange membrane for a polymer electrolyte fuel cell comprising the same.

  A fuel cell is one that converts the chemical energy of fuel directly into electrical energy by electrochemically oxidizing hydrogen, methanol, etc. in the battery, and is attracting attention as a clean electrical energy supply source. ing. In particular, polymer electrolyte fuel cells are expected to be used as alternative power sources for automobiles, home cogeneration systems, portable generators, and the like because they operate at a lower temperature than others.

  Such a polymer electrolyte fuel cell includes at least a membrane electrode assembly in which a gas diffusion electrode in which an electrode catalyst layer and a gas diffusion layer are laminated is bonded to both surfaces of a proton exchange membrane. The proton exchange membrane here is a material having a strong acidic group such as a sulfonic acid group and a carboxylic acid group in the polymer chain and a property of selectively transmitting protons. As such a proton exchange membrane, a perfluoro proton exchange membrane represented by Nafion (registered trademark, manufactured by DuPont) having high chemical stability is preferably used.

  During operation of the fuel cell, fuel (for example, hydrogen) is supplied to the gas diffusion electrode on the anode side, and an oxidant (for example, oxygen or air) is supplied to the gas diffusion electrode on the cathode side. Operates by connecting. Specifically, when hydrogen is used as a fuel, hydrogen is oxidized on the anode catalyst to generate protons, and after passing through the proton conductive polymer in the anode catalyst layer, the protons move in the proton exchange membrane, It reaches the cathode catalyst through the proton conducting polymer in the cathode catalyst layer. On the other hand, electrons generated simultaneously with protons by oxidation of hydrogen reach the cathode side gas diffusion electrode through an external circuit, and react with the protons and oxygen in the oxidant on the cathode catalyst to generate water, At this time, electric energy can be taken out.

  At this time, the proton exchange membrane also needs to play a role as a gas barrier. When the gas permeability of the proton exchange membrane is high, leakage of anode-side hydrogen to the cathode side and leakage of cathode-side oxygen to the anode side, that is, A cross leak occurs, so that a so-called chemical short circuit occurs and a good voltage cannot be taken out.

  Such a polymer electrolyte fuel cell is usually operated near 80 ° C. in order to obtain high output characteristics. However, when used for automobiles, the fuel cell can be operated even under high-temperature and low-humidification conditions (operating temperature near 100 ° C., 50 ° C. humidification (corresponding to a humidity of 12 RH%)) assuming that the vehicle is driven in summer. It is desired. However, when a fuel cell is operated for a long time under a high temperature and low humidity condition using a conventional perfluoro proton exchange membrane, there is a problem that pinholes are generated in the proton exchange membrane, and cross leaks occur. Is not obtained.

  As a method for improving the durability of the perfluoro proton exchange membrane, reinforcement using fibrillar polytetrafluoroethylene (PTFE) (Japanese Patent Laid-Open No. 53-149881 and Japanese Patent Publication No. 63-61337), stretching treatment Reinforcement using a porous PTFE membrane (JP-A-8-162132), reinforcement added with inorganic particles (JP-A-6-1111827, JP-A-9-219206 and US Pat. No. 5,523,181), In addition, studies have been reported on reinforcement using a porous body made of an aromatic ring-containing resin (Japanese Patent Laid-Open Nos. 2001-514431 and 2003-293393). However, in these methods, it has not been achieved to obtain a durability sufficient to solve the above problems.

  An object of the present invention is to provide a polymer electrolyte composition having high durability even under high-temperature and low-humidity conditions (for example, at an operating temperature of 100 ° C. and 50 ° C. humidification (corresponding to a humidity of 12 RH%)), and the polymer electrolyte composition. It is providing the proton exchange membrane which becomes.

  As a result of intensive studies to solve the above problems, the present inventors have found that a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), a polyphenylene ether resin (C) and / or a polysulfone resin (D It has been found that the proton exchange membrane comprising the polymer electrolyte composition has very good high durability even under high temperature and low humidity.

That is, the present invention is as follows.
[1] A polymer electrolyte composition comprising a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), and a polyphenylene ether resin (C) and / or a polysulfone resin (D).
[2] The polymer electrolyte composition according to the above [1], wherein the polyphenylene ether resin (C) is an epoxy-modified polyphenylene ether (E).
[3] The high molecular structure according to [1] or [2], comprising the polymer compound (A) having an ion exchange group, the polyphenylene sulfide resin (B), the polyphenylene ether resin (C), and the epoxy group-containing compound (F). Molecular electrolyte composition.
[4] The polymer electrolyte composition according to the above [3], wherein the epoxy group-containing compound (F) is a homopolymer or copolymer (G) of an unsaturated monomer having an epoxy group.
[5] The polymer electrolyte composition according to the above [4], wherein the epoxy group-containing compound (F) is a copolymer (G) containing an unsaturated monomer having an epoxy group and a styrene monomer.
[6] The polymer electrolyte composition according to the above [3], wherein the epoxy group-containing compound (F) is an epoxy resin (H).
[7] The polymer electrolyte composition as described in [6] above, wherein an epoxy formed by reacting at least a part of the polyphenylene ether resin (C) and the epoxy resin (H) in the polymer electrolyte composition A polymer electrolyte composition containing a modified polyphenylene ether (E).
[8] The polymer electrolyte composition according to any one of [1] to [7], wherein the polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group.
[9] The polymer electrolyte composition according to the above [8], wherein the perfluorocarbon polymer compound having an ion exchange group has a structural unit represented by the following general formula (1).
-[CF ₂ CX ¹ X ² ] _a- [CF ₂ -CF (-O- (CF ₂ -CF (CF ₂ X ³ )) _b -O _c- (CFR ¹ ) _d- (CFR ² ) _e- ( CF ₂ ) _f -X ⁴ )] _g- (1)
In the formula, X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, and a and g are 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, b is an integer of 0 or more and 8 or less, c is 0 or 1, d, e and f are each independently an integer of 0 or more and 6 or less (however, d + e + f is not equal to 0) , R ¹ and R ² are each independently a halogen element, a perfluoroalkyl group or a fluorochloroalkyl group having 1 to 10 carbon atoms, and X ⁴ is COOZ, SO ₃ Z, PO ₃ Z ₂ or PO ₃ HZ. is there. Here, Z is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or an amine (NH ₄ , NH ₃ R ₁ , NH ₂ R ₁ R ₂ , NHR ₁ R ₂ R ₃ , NR ₁ R ₂ R ₃ R ₄ R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups or arene groups.
[10] Particles containing at least one resin selected from polyphenylene sulfide resin (B), polyphenylene ether resin (C) and polysulfone resin (D) in perfluorocarbon polymer compound (A) having an ion exchange group The polymer electrolyte composition according to any one of the above [1] to [9], wherein the particles have an average particle diameter in terms of a circle of 1 μm or less.
[11] Particles containing at least one resin selected from polyphenylene sulfide resin (B), polyphenylene ether resin (C) and epoxy group-containing compound (F) in polymer compound (A) having an ion exchange group The polymer electrolyte composition according to any one of the above [3] to [9], wherein the particles are dispersed and the average particle diameter in terms of a circle is 1 μm or less.
[12] The polymer electrolyte composition according to the above [10] or [11], wherein the region in which the particles are dispersed is 50 to 100% with respect to the entire region of the polymer electrolyte composition.
[13] A proton exchange membrane comprising the polymer electrolyte composition according to any one of [1] to [12] above.
[14] The polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group, and a polyphenylene sulfide resin (B) and a precursor of the perfluorocarbon polymer compound having an ion exchange group A film obtained by heat-melting and mixing the polyphenylene ether resin (C) and / or the polysulfone resin (D) and then extrusion-molding the film was saponified with an alkali and then acid-treated. The proton exchange membrane according to [13], which is 200 μm.
[15] The polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group, and a polyphenylene sulfide resin (B) is used as a precursor of the perfluorocarbon polymer compound having an ion exchange group, The film obtained by heat-melting and mixing the polyphenylene ether resin (C) and the epoxy group-containing compound (F) and then extrusion molding was saponified with alkali, and then manufactured by acid treatment. The proton exchange membrane according to [13], which is 200 μm.
[16] The proton exchange membrane according to the above [14] or [15], wherein the extrusion molding is inflation molding.
[17] The above-mentioned stretch-treated film of 1.1 to 6.0 times in the transverse (TD) direction, 1.0 to 6.0 times in the longitudinal (MD) direction, and 1.1 to 36 times in area stretch ratio [ The proton exchange membrane according to any one of [13] to [16].
[18] The proton exchange membrane according to any one of [13] to [17], wherein at least two types of proton exchange membranes made of polymer electrolyte compositions having different composition ratios are laminated.
[19] The above [18], wherein the polymer electrolyte composition comprises a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), a polyphenylene ether resin (C), and an epoxy group-containing compound (F). Proton exchange membrane.
[20] At least three proton exchange membranes composed of at least two types of polymer electrolyte compositions having different contents of the polymer compound (A) having an ion exchange group are laminated, and from at least one of the surface layers The proton exchange membrane as described in [18] or [19] above, wherein the inner layer having a low A content is 5 to 90% of the total layer thickness.
[21] At least three proton exchange membranes composed of at least two types of polymer electrolyte compositions having different content of the polymer compound (A) having an ion exchange group are laminated, and the content of A in the surface layer Is less than the inner layer, and the thickness of the surface layer is 5 to 50% of the total layer thickness.
[22] The proton exchange membrane according to any one of [13] to [21], which contains a reinforcing material made of an inorganic material or an organic material.
[23] The proton exchange membrane according to [22], wherein the reinforcing material is a short fiber substance.
[24] The proton exchange membrane according to [22], wherein the reinforcing material is a continuous support.
[25] A membrane electrode assembly comprising the proton exchange membrane according to the above [13] to [24].
[26] A polymer electrolyte fuel cell comprising the membrane electrode assembly according to [25].

  The proton exchange membrane comprising the polymer electrolyte composition of the present invention is excellent in that no cross leak occurs even when the fuel cell is operated for a long period of time at an operating temperature of 100 ° C. and humidified at 50 ° C. (equivalent to a humidity of 12 RH%). Because of its high durability, it has become possible to obtain a proton exchange membrane having high durability even under high temperature and low humidification conditions (for example, at an operating temperature of 100 ° C. and 50 ° C. humidification (equivalent to a humidity of 12 RH%)). .

  The proton exchange membrane obtained by the present invention can also be used in various fuel cells including direct methanol fuel cells, water electrolysis, hydrohalic acid electrolysis, salt electrolysis, oxygen concentrators, humidity sensors, gas sensors, etc. is there.

  The present invention is described in detail below.

  Examples of the polymer compound (A) having an ion exchange group used in the present invention include an ion exchange group in a perfluorocarbon polymer compound having an ion exchange group or a hydrocarbon polymer compound having an aromatic ring in the molecule. Those into which are introduced are preferred. Specific examples of the hydrocarbon polymer compound having an aromatic ring in the molecule include polyphenylene sulfide, polyphenylene ether, polysulfone, polyether sulfone, polyether ether sulfone, polyether ketone, polyether ether ketone, and polythioether ether. Sulfone, polythioetherketone, polythioetheretherketone, polybenzimidazole, polybenzoxazole, polyoxadiazole, polybenzoxazinone, polyxylylene, polyphenylene, polythiophene, polypyrrole, polyaniline, polyacene, polycyanogen, polynaphthyridine, polyphenylene sulfide sulfone, Polyphenylenesulfone, polyimide, polyetherimide, polyesterimide, polyamideimide, polyester Arylate, aromatic polyamide, polystyrene, polyester, and polycarbonate. From the viewpoint of heat resistance, oxidation resistance and hydrolysis resistance, polyphenylene sulfide, polyphenylene ether, polysulfone, polyether sulfone, polyether ether sulfone, polyether ketone, polyether ether ketone, polythioether ether sulfone, polythioether ketone, poly Thioether ether ketone, polybenzimidazole, polybenzoxazole, polyoxadiazole, polybenzoxazinone, polyxylylene, polyphenylene, polythiophene, polypyrrole, polyaniline, polyacene, polycyanogen, polynaphthyridine, polyphenylene sulfide sulfone, polyphenylene sulfone, polyimide, polyether An imide is preferred. The ion exchange group introduced into these is preferably, for example, a sulfonic acid group, a sulfonimide group, a sulfonamide group, a carboxylic acid group, or a phosphoric acid group, and particularly preferably a sulfonic acid group.

  As the polymer compound (A) having an ion exchange group used in the present invention, a perfluorocarbon polymer compound having an ion exchange group is particularly suitable.

As the perfluorocarbon polymer compound having an ion exchange group, a sulfonic acid polymer of perfluorocarbon, a carboxylic acid polymer, a sulfonimide polymer, a sulfonamide polymer, a phosphoric acid polymer, or an amine salt or a metal salt thereof is preferably used. Specific examples thereof include a polymer represented by the following general formula (1).
-[CF ₂ CX ¹ X ² ] _a- [CF ₂ -CF (-O- (CF ₂ -CF (CF ₂ X ³ )) _b -O _c- (CFR ¹ ) _d- (CFR ² ) _e- ( CF ₂ ) _f -X ⁴ )] _g- (1)
In the formula, X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, and a and g are 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, b is an integer of 0 or more and 8 or less, c is 0 or 1, d, e and f are each independently an integer of 0 or more and 6 or less (however, d + e + f is not equal to 0) , R ¹ and R ² are each independently a halogen element, a perfluoroalkyl group or a fluorochloroalkyl group having 1 to 10 carbon atoms, and X ⁴ is COOZ, SO ₃ Z, PO ₃ Z ₂ or PO ₃ HZ. is there. Here, Z is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or an amine (NH ₄ , NH ₃ R ₁ , NH ₂ R ₁ R ₂ , NHR ₁ R ₂ R ₃ , NR ₁ R ₂ R ₃ R ₄ R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups or arene groups.

  Among these, a perfluorocarbon sulfonic acid polymer represented by the following general formula (2) or (3) or a metal salt thereof is particularly preferable.

-[CF ₂ CF ₂ ] _a- [CF ₂ -CF (-O-CF ₂ -CF (CF ₃ )) _b -O- (CF ₂ ) _c -SO ₃ X]] _d- (2)
In the formula, a and d are 0 ≦ a <1, 0 ≦ d <1, a + d = 1, b is an integer of 1 to 8, c is an integer of 0 to 10, and X is hydrogen An atom or an alkali metal atom.

-[CF ₂ CF ₂ ] _e- [CF ₂ -CF (-O- (CF ₂ ) _f -SO ₃ Y)] _g- (3)
In the formula, e and g are 0 ≦ e <1, 0 ≦ g <1, e + g = 1, f is an integer of 0 or more and 10 or less, and Y is a hydrogen atom or an alkali metal atom.

The perfluorocarbon polymer compound having an ion exchange group used in the present invention can be produced, for example, by polymerizing a precursor polymer represented by the following general formula (4), followed by alkali hydrolysis, acid treatment and the like. .
-[CF ₂ CX ¹ X ² ] _a- [CF ₂ -CF (-O- (CF ₂ -CF (CF ₂ X ³ )) _b -O _c- (CFR ¹ ) _d- (CFR ² ) _e- ( CF ₂ ) _f -X ⁵ )] _g- (4)
In the formula, X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, and a and g are 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, b is an integer of 0 or more and 8 or less, c is 0 or 1, d, e and f are each independently an integer of 0 or more and 6 or less (however, d + e + f is not equal to 0) , R ¹ and R ² are each independently a halogen element, a perfluoroalkyl group or a fluorochloroalkyl group having 1 to 10 carbon atoms, and X ⁵ is COOR ³ , COR ⁴ or SO ₂ R ⁴ . Here, R ³ is a hydrocarbon alkyl group having 1 to ³ carbon atoms, and R ⁴ is a halogen element.

  The precursor polymer that can be used in the present invention is produced by copolymerizing a fluorinated olefin compound and a vinyl fluoride compound.

Specific examples of the fluorinated olefin compound include CF ₂ = CF ₂ , CF ₂ = CFCl, CF ₂ = CCl _{2 and the} like.

Further, as a specific fluorinated vinyl _{compounds, CF 2 = CFO (CF 2} ) z -SO 2 F, CF 2 = CFOCF 2 CF (CF 3) O (CF 2) z -SO 2 F, CF 2 = _{CF (CF 2) z -SO 2} F, CF 2 = CF (OCF 2 CF (CF 3)) z - (CF 2) z-1 -SO 2 F, CF 2 = CFO (CF 2) z -CO 2 _{R, CF2 = CFOCF 2 CF (} CF 3) O (CF 2) z -CO 2 R, CF 2 = CF (CF 2) z -CO 2 R, CF 2 = CF (OCF 2 CF (CF 3)) z _{- (CF 2) 2 -CO 2} R ( an integer of Z is 1 to 8, R represents a hydrocarbon-based alkyl group having 1 to 3 carbon atoms) and the like.

  As a polymerization method of the precursor polymer, a solution polymerization method in which a vinyl fluoride compound is dissolved in a solvent such as chlorofluorocarbon and then reacted with a gas of a fluorinated olefin compound to perform polymerization, or a block shape in which polymerization is performed without using a solvent such as chlorofluorocarbon General polymerization methods such as a polymerization method, an emulsion polymerization method in which a vinyl fluoride compound is mixed with a surfactant in water and emulsified, and then reacted with a gas of a fluorinated olefin compound for polymerization.

  In the present invention, in addition to a vinyl fluoride compound and a fluorinated olefin compound, a copolymer containing a third component such as a perfluoroolefin such as hexafluoropropylene or chlorotrifluoroethylene and a perfluoroalkyl vinyl ether may be used. Good.

  The melt index MI (g / 10 min) of the precursor polymer that can be used in the present invention, measured at 270 ° C., load 21.2 N, orifice inner diameter 2.09 mm based on JIS K-7210 is 0.00. 001 or more and 1000 or less are preferable, more preferably 0.01 or more and 100 or less, and most preferably 0.1 or more and 10 or less.

  Next, the precursor polymer that can be used in the present invention is immersed in a basic reaction liquid and subjected to an alkali hydrolysis treatment. The reaction liquid is preferably an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as potassium hydroxide or sodium hydroxide. The content of alkali metal or alkaline earth metal hydroxide is preferably 10% by mass or more and 30% by mass or less. The reaction liquid preferably contains a swellable organic compound such as dimethyl sulfoxide or methanol. The content of the swellable organic compound is preferably 1% by mass or more and 30% by mass or less.

  After the precursor polymer is subjected to an alkali hydrolysis treatment, and further subjected to an acid treatment with hydrochloric acid or the like as necessary, a perfluorocarbon polymer compound having an ion exchange group is produced.

  The polyphenylene sulfide resin (B) used in the present invention (hereinafter sometimes abbreviated as PPS) is not particularly limited as long as it is a so-called polyphenylene sulfide resin, but preferably has a paraphenylene sulfide skeleton of 70 mol% or more, more preferably It is a polyphenylene sulfide resin comprising 90 mol% or more.

  The production method of PPS is not particularly limited. Usually, a halogen-substituted aromatic compound such as p-dichlorobenzene is polymerized in the presence of sulfur and sodium carbonate, and p-dichlorobenzene is reacted in a polar solvent. A method of polymerizing in the presence of sodium sulfide or sodium hydrogen sulfide and sodium hydroxide, or a method of polymerizing p-dichlorobenzene in a polar solvent in the presence of hydrogen sulfide and sodium hydroxide or sodium aminoalkanoate, p- Examples include self-condensation of chlorothiophenol. Among these, a method of reacting sodium sulfide and p-dichlorobenzene in an amide solvent such as N-methylpyrrolidone or dimethylacetamide or a sulfone solvent such as sulfolane is suitable. Specifically, U.S. Pat. No. 2,513,188, JP-B-44-27671, JP-B-45-3368, JP-B-52-12240, JP-A-61-225217, U.S. Pat. No. 3,274,165. No. 1, British Patent No. 1160660, Japanese Patent Publication No. Sho 46-27255, Belgian Patent No. 29437, and Japanese Patent Laid-Open No. 5-222196, etc. It can be obtained by technical methods.

  In the polyphenylene sulfide resin (B) used in the present invention, the amount of oligomer extracted with methylene chloride is 0.001 wt% or more and 0.9 wt% or less, and the —SX group (S is a sulfur atom, X is an alkali A polyphenylene sulfide resin having a metal or hydrogen atom of 10 μmol / g or more and 10,000 μmol / g or less is preferable.

  The amount of oligomer extracted with methylene chloride is more preferably 0.001 wt% or more and 0.8 wt% or less, and particularly preferably 0.001 wt% or more and 0.7 wt% or less. That the amount of oligomer extracted with methylene chloride is in the above range means that the amount of oligomer (about 10 to 30 mer) in PPS is small. If the amount of oligomer extraction exceeds the above range, bleeding out tends to occur during film formation, which is not preferable.

  Here, the amount of oligomer extracted with methylene chloride can be measured by the following method. That is, 5 g of PPS powder is added to 80 ml of methylene chloride, Soxhlet extraction is performed for 4 hours, and then cooled to room temperature, and the methylene chloride solution after extraction is transferred to a weighing bottle. Further, the container used for the above extraction is washed in three portions with a total of 60 ml of methylene chloride, and the washing liquid is collected in the weighing bottle. Next, the methylene chloride in the weighing bottle is evaporated and removed by heating to about 80 ° C., the residue is weighed, and the ratio of the amount of oligomer present in the PPS can be determined from the amount of the residue.

  In addition, the content of the —SX group is more preferably 15 μmol / g or more and 10,000 μmol / g or less, particularly preferably 20 μmol / g or more and 10,000 μmol / g or less. The fact that the -SX group concentration is in the above range means that there are many reaction active sites of the polyphenylene sulfide resin. -By using a polyphenylene sulfide resin in which the SX group concentration satisfies the above range, the miscibility between the polymer compound (A) having an ion exchange group and the polyphenylene sulfide resin (B) is improved in the polymer electrolyte composition of the present invention. It is considered that the dispersibility of the polyphenylene sulfide resin (B) in the polymer compound (A) having an ion exchange group is improved.

  Here, quantification of the —SX group can be performed by the following method. That is, after the PPS powder was previously dried at 120 ° C. for 4 hours, 20 g of this dried PPS powder was added to 150 g of N-methyl-2-pyrrolidone, and the mixture was vigorously stirred and mixed at room temperature for 30 minutes so as to eliminate powder agglomerates. To do. After the obtained slurry is filtered, washing is repeated 7 times using 1 liter of warm water of about 80 ° C. each time. The obtained filter cake is slurried again in 200 g of pure water, and 1N hydrochloric acid is added to adjust the pH of the slurry to 4.5. Next, after stirring at 25 ° C. for 30 minutes and filtering, washing is repeated 6 times using 1 liter of hot water at about 80 ° C. The obtained filter cake is slurried again in 200 g of pure water, then titrated with 1N sodium hydroxide, and the amount of -SX groups present in the PPS is determined from the amount of sodium hydroxide consumed.

  As a specific method for producing PPS, the amount of oligomer extracted with methylene chloride is 0.001 wt% or more and 0.9 wt% or less, and the —SX group is 10 μmol / g or more and 10,000 μmol / g or less. The production methods (paragraph numbers 0041 to 0044) described in Examples 1 and 2 of JP-A-8-253687 and the production methods (paragraph numbers) described in synthesis examples 1 and 2 of JP-A-11-106656 0046 to 0048).

  Furthermore, the PPS used in the present invention was held for 6 minutes at a melt viscosity at 320 ° C. (300 ° C., load 196 N, L / D (L: orifice length, D: orifice inner diameter) = 10/1 using a flow tester). Value) is preferably 1 to 10,000 poise, more preferably 100 to 10,000 poise.

  Moreover, in this invention, what introduce | transduced the acidic functional group and the reactive functional group into polyphenylene sulfide resin can be used suitably as polyphenylene sulfide resin (B). By introducing such a functional group, the miscibility between the polymer compound (A) having an ion exchange group and the polyphenylene sulfide resin (B) in the polymer electrolyte composition of the present invention is improved, and the ion exchange group is reduced. It is considered that the dispersibility of the polyphenylene sulfide resin (B) in the polymer compound (A) is improved. In particular, when an acidic functional group is introduced, it means that the functional group involved in proton conductivity is increased in the proton exchange membrane made of the polymer electrolyte of the present invention, and it is preferable because high proton conductivity can be expressed. Examples of acidic functional groups to be introduced include sulfonic acid groups, phosphoric acid groups, sulfonimide groups, carboxylic acid groups, maleic acid groups, maleic anhydride groups, fumaric acid groups, itaconic acid groups, acrylic acid groups, and methacrylic acid groups. Are preferred, sulfonic acid groups and phosphoric acid groups which are strong acid groups are more preferred, and sulfonic acid groups are most preferred. As the reactive functional group to be introduced, an epoxy group, an oxazonyl group, an amino group, an isocyanate group, a carbodiimide group, and the like are preferable, and an epoxy group is particularly preferable. Further, two or more of the above various functional groups may be introduced.

  The method for introducing an acidic functional group or a reactive functional group is not particularly limited, and can be introduced using a general method. For example, introduction of a sulfonic acid group can be carried out under known conditions using a sulfonating agent such as sulfuric anhydride or fuming sulfuric acid. For example, K.K. Hu, T .; Xu, W .; Yang, Y. et al. Fu, Journal of Applied Polymer Science, Vol. 91 and E.I. Montoneri, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 27, 3043-3051 (1989).

  Further, those in which the introduced acidic functional group is substituted with a metal salt or an amine salt are also preferably used. The metal salt is preferably an alkali metal salt such as sodium salt or potassium salt, or an alkaline earth metal salt such as calcium salt.

  The polyphenylene ether resin (hereinafter sometimes simply referred to as PPE) (C) used in the present invention is not particularly limited as long as it is a so-called polyphenylene ether resin, but a structural unit represented by the following general formula (5) is used. A phenol homopolymer or copolymer containing 70 mol% or more, preferably 90 mol% or more is preferred.

  Here, R1, R2, R3 and R4 are each hydrogen, halogen, a linear or branched lower alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbonoxy group, or at least The two carbon atoms are selected from the group consisting of a halohydrocarbonoxy group separating a halogen atom and an oxygen atom, and may be the same or different from each other.

  Specific examples of the PPE include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2-methyl). -6-phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether) and the like, and 2,6-dimethylphenol and other monohydric phenols (for example, 2,3,6-trimethylphenol and 2-methyl-6-butylphenol), 2,6-dimethylphenol and divalent phenols (for example, 3,3 ′, 5,5′-tetramethylbisphenol A) A copolymer etc. are mentioned. Among these, poly (2,6-dimethyl-1,4-phenylene ether), a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, 2,6-dimethylphenol and 3,3 A copolymer with ', 5,5'-tetramethylbisphenol A is preferred.

  The polyphenylene ether resin (C) used in the present invention preferably has a phenolic hydroxyl group at the molecular chain end, and the position may be one end or both ends.

  The reduced viscosity (0.5 g / dl, chloroform solution, measured at 30 ° C.) of the polyphenylene ether resin (C) used in the present invention is preferably in the range of 0.05 to 2.0 dl / g. More preferably, it is in the range of 0.8 dl / g.

  The production method of the polyphenylene ether resin (C) used in the present invention is not particularly limited. For example, as described in US Pat. No. 3,306,874, a complex of cuprous salt and amine is used as a catalyst. For example, it can be easily produced by oxidative polymerization of 2,6-xylenol. In addition, U.S. Pat. Nos. 3,306,875, 3,257,357, 3,257,358, JP-B-52-17880, JP-A-50-51197, and JP-A-63-152628 are disclosed. Can be easily produced by the method described in the above.

  Moreover, in this invention, what introduce | transduced the acidic functional group and the reactive functional group into polyphenylene ether resin can be used suitably as polyphenylene ether resin (C). By introducing such a functional group, the miscibility between the polymer compound (A) having an ion exchange group and the polyphenylene ether resin (C) in the polymer electrolyte composition of the present invention is improved, and the ion exchange group is reduced. It is considered that the dispersibility of the polyphenylene ether resin (C) in the polymer compound (A) is improved. In particular, when an acidic functional group is introduced, it means that the functional group involved in proton conductivity is increased in the proton exchange membrane made of the polymer electrolyte of the present invention, and it is preferable because high proton conductivity can be expressed. Examples of acidic functional groups to be introduced include sulfonic acid groups, phosphoric acid groups, sulfonimide groups, carboxylic acid groups, maleic acid groups, maleic anhydride groups, fumaric acid groups, itaconic acid groups, acrylic acid groups, and methacrylic acid groups. Are preferred, sulfonic acid groups and phosphoric acid groups which are strong acid groups are more preferred, and sulfonic acid groups are most preferred. As the reactive functional group to be introduced, an epoxy group, an oxazonyl group, an amino group, an isocyanate group, a carbodiimide group, and the like are preferable, and an epoxy group is particularly preferable. Further, two or more of the above various functional groups may be introduced.

  The method for introducing an acidic functional group or a reactive functional group is not particularly limited, and can be introduced using a general method. For example, introduction of a sulfonic acid group can be carried out under known conditions using a sulfonating agent such as sulfuric anhydride or fuming sulfuric acid. For example, C.I. Wang, Y .; Huang, G .; Cong, Polymer Journal, Vol. 27, no. 2, 173-178 (1995) and J. Am. Schauer, W. et al. Albrecht, T .; Weigel, Journal of Applied Polymer Science, Vol. 73, 161-167 (1999).

  Further, those in which the introduced acidic functional group is substituted with a metal salt or an amine salt are also preferably used. The metal salt is preferably an alkali metal salt such as sodium salt or potassium salt, or an alkaline earth metal salt such as calcium salt.

  The polysulfone resin (D) used in the present invention is not particularly limited as long as it is a so-called polysulfone resin, but a polysulfone resin having a structure represented by the following general formula (6) of 80 mol% or more, preferably 90 mol% or more is used. preferable.

  The production method of the polysulfone resin (D) used in the present invention is not particularly limited. For example, the polysulfone resin (D) can be easily produced by reacting a sodium salt of bisphenol A with 4,4′-dichlorodiphenylsulfone.

  Moreover, in this invention, what introduce | transduced the acidic functional group and the reactive functional group into polysulfone resin can be used suitably as polysulfone resin (D). By introducing such a functional group, the miscibility between the polymer compound (A) having an ion exchange group and the polysulfone resin (D) is improved in the polymer electrolyte composition of the present invention, and the ion exchange group is contained. It is considered that the dispersibility of the polysulfone resin (D) in the polymer compound (A) is improved. In particular, when an acidic functional group is introduced, it means that the functional group involved in proton conductivity is increased in the proton exchange membrane made of the polymer electrolyte of the present invention, and it is preferable because high proton conductivity can be expressed. Examples of acidic functional groups to be introduced include sulfonic acid groups, phosphoric acid groups, sulfonimide groups, carboxylic acid groups, maleic acid groups, maleic anhydride groups, fumaric acid groups, itaconic acid groups, acrylic acid groups, and methacrylic acid groups. Are preferred, sulfonic acid groups and phosphoric acid groups which are strong acid groups are more preferred, and sulfonic acid groups are most preferred. As the reactive functional group to be introduced, an epoxy group, an oxazonyl group, an amino group, an isocyanate group, a carbodiimide group, and the like are preferable, and an epoxy group is particularly preferable. Further, two or more of the above various functional groups may be introduced.

  The method for introducing an acidic functional group or a reactive functional group is not particularly limited, and can be introduced using a general method. For example, introduction of a sulfonic acid group can be carried out under known conditions using a sulfonating agent such as sulfuric anhydride or fuming sulfuric acid.

  Further, those in which the introduced acidic functional group is substituted with a metal salt or an amine salt are also preferably used. The metal salt is preferably an alkali metal salt such as sodium salt or potassium salt, or an alkaline earth metal salt such as calcium salt.

  The polymer electrolyte composition of the present invention comprises the above-described polymer compound (A) having an ion exchange group, polyphenylene sulfide resin (B), polyphenylene ether resin (C) and / or polysulfone resin (D). It is a thing. Such a polyelectrolyte composition of the present invention and a proton exchange membrane comprising the composition include a polyphenylene sulfide resin (B), a polyphenylene ether, as compared with the polymer compound (A) having an ion exchange group alone. Even when the resin (C) and the polysulfone resin (D) are each contained alone in the polymer compound (A) having an ion exchange group, the durability is remarkably improved. Surprisingly, the polymer electrolyte composition of the present invention contains many resins including the resin used in the present invention in the polymer compound (A) having an ion exchange group in various combinations other than the present invention. The durability is remarkably improved as compared with the case of making them.

  Next, the composition ratio of the polymer compound (A) having an ion exchange group, the polyphenylene sulfide resin (B), the polyphenylene ether resin (C) and the polysulfone resin (D) in the polymer electrolyte composition of the present invention will be described. .

  In the polymer electrolyte composition of the present invention, the mass ratio of the polyphenylene sulfide resin (B) to the polyphenylene ether resin (C) and / or the polysulfone resin (D) is B / (C + D) = 1/99 to 99. / 1 is preferable. More preferably, B / (C + D) = 20/80 to 95/5, and most preferably B / (C + D) = 30/70 to 90/10.

  The mass ratio ((B + C + D) / A) of the polyphenylene sulfide resin (B), the polyphenylene ether resin (C) and the polysulfone resin (D) to the polymer compound (A) having an ion exchange group is 99/1 to 0. 0.01 / 99.99 is preferred. From the balance between proton conductivity and durability, (B + C + D) / A is more preferably 90/10 to 0.05 / 99.95, further preferably 70/30 to 0.1 / 99.9, and 50/50 to 1/99 is particularly preferable, and 30/70 to 5/95 is most preferable.

  When the polymer electrolyte composition of the present invention contains a polyphenylene ether resin (C), it is preferable to contain an epoxy group-containing compound (F). When the polymer electrolyte composition containing at least the polymer compound (A) having an ion exchange group, the polyphenylene sulfide resin (B) and the polyphenylene ether resin (C) contains the epoxy group-containing compound (F), the polymer The particle dispersibility in the electrolyte composition is improved, and as a result, the durability of the polymer electrolyte composition and the proton exchange membrane made of the composition is further improved.

  The epoxy group-containing compound (F) used in the present invention is not particularly limited as long as it is a compound having an epoxy group. For example, a low molecular compound containing an epoxy group, a homopolymer of an unsaturated monomer having an epoxy group, or A copolymer (G), an epoxy resin (H), etc. are mentioned. Since the polymer compound is easier to handle at high temperatures, a homopolymer or copolymer (G) of an unsaturated monomer having an epoxy group and an epoxy resin (H) are preferred.

  The low molecular weight compound containing an epoxy group is preferably a solid or liquid at 200 ° C., specifically, 1,2-epoxy-3-phenoxypropane, N- (2,3-epoxypropyl). ) Phthalimide, 3,4-epoxytetrahydrothiophene-1,1-dioxide, glycidyl 4-nonylphenyl ether, glycidyl tosylate, glycidyl trityl ether, and the like.

  The content of the epoxy group-containing compound (F) is preferably F / (B + C) = 1/100 to 200/100 with respect to the total mass of the polyphenylene sulfide resin (B) and the polyphenylene ether resin (C). (B + C) = 2/100 to 100/100 is more preferable, and F / (B + C) = 3/100 to 50/100 is particularly preferable.

  The unsaturated monomer having an epoxy group constituting the homopolymer or copolymer (G) of the unsaturated monomer having an epoxy group used in the present invention is not limited as long as it is an unsaturated monomer having an epoxy group. Examples thereof include glycidyl methacrylate, glycidyl acrylate, vinyl glycidyl ether, glycidyl ether of hydroxyalkyl (meth) acrylate, glycidyl ether of polyalkylene glycol (meth) acrylate, glycidyl itaconate and the like. Among these, glycidyl methacrylate is preferable.

  In the case of a copolymer of an unsaturated monomer having an epoxy group, other unsaturated monomers copolymerized with the unsaturated monomer having an epoxy group include vinyl aromatic compounds such as styrene, vinyl cyanide monomers such as acrylonitrile, Vinyl acetate, (meth) acrylic acid ester and the like are preferable. Examples of copolymers obtained by copolymerizing these copolymerizable unsaturated monomers include, for example, styrene-glycidyl methacrylate copolymer, styrene-glycidyl methacrylate-methyl methacrylate copolymer, styrene-glycidyl methacrylate-acrylonitrile copolymer. A polymer etc. are mentioned.

  Among these copolymers, a copolymer containing an unsaturated monomer having an epoxy group and a styrene monomer is particularly excellent in affinity with the polyphenylene ether resin (C), and the dispersibility of the polyphenylene ether resin (C) is excellent. Since it improves especially, it is preferable. From the viewpoint of improving dispersibility, it is preferable to contain at least 65% by mass of a styrene monomer. Moreover, it is preferable to contain 0.3-20 mass% of unsaturated monomers which have an epoxy group, It is more preferable to include 1-15 mass%, It is especially preferable that 3-10 mass% is included.

  Examples of the epoxy resin (H) used in the present invention include a cresol novolac type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a hindered type epoxy resin, a biphenyl type epoxy resin, and an alicyclic ring. And epoxy epoxy resin, triphenylmethane type epoxy resin and phenol novolac type epoxy resin. One or more selected from these may be used in combination. Among them, cresol novolac type epoxy resins and bisphenol A type epoxy resins are preferable, and cresol novolac type epoxy resins are particularly preferable.

  In the present invention, the polyphenylene ether resin (C) and the epoxy resin (H) can be added by mixing and reacting in advance. That is, as the polyphenylene ether resin (C), an epoxy-modified polyphenylene ether resin (E) obtained by reacting a polyphenylene ether resin and an epoxy resin can be used. Of course, after the polyphenylene ether resin (C) and the epoxy resin (H) are mixed together with the components (A) and (B) to obtain the composition of the present invention, the polyphenylene ether resin (C) is used under the conditions described later. And epoxy resin (H) may be reacted.

  By using the epoxy-modified polyphenylene ether resin (E) as the polyphenylene ether resin (C), the dispersibility of the obtained polymer electrolyte composition is improved. As a result, the polymer electrolyte composition and the protons comprising this composition are improved. The durability of the exchange membrane is further improved.

  In the method for producing the epoxy-modified polyphenylene ether resin (E), the reaction temperature is preferably 100 to 250 ° C. More preferably, it is 120-195 degreeC, More preferably, it is the range of 140-190 degreeC. The reaction time is preferably less than 3 hours, more preferably within 2 hours, particularly preferably within 40 minutes.

  The reactor used for the production of the epoxy-modified polyphenylene ether resin (E) is preferably one that can uniformly mix, stir or knead the polyphenylene ether resin and the epoxy resin. If the viscosity is high, a kneader such as a twin screw extruder or kneader Can be used. The manufacturing method can use any process form of a continuous reaction process, a batch reaction process, and a semi-batch reaction process.

In the production method of the epoxy-modified polyphenylene ether resin (E), a basic compound can be added to the reaction system from the viewpoint of improving the reaction rate, suppressing side reactions, and controlling the structure of the reaction composition E. Specific examples of basic compounds include lithium, sodium, potassium, sodium methylate, sodium ethylate, tertiary amines such as triethylamine and tributylamine, imidazole, sodium phenoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, Examples include potassium carbonate and sodium carbonate. Among these, sodium methylate, triethylamine, tributylamine, sodium hydroxide and the like are preferable. In addition to the above basic compounds, quaternary ammonium salts can also be used as catalysts.
In the present invention, each of the components (A) to (H) may be composed of two or more kinds of compounds. For example, as the polyphenylene ether resin (C), a mixture of poly (2,6-dimethyl-1,4-phenylene ether) and poly (2-methyl-6-ethyl-1,4-phenylene ether) is used. Examples include using a mixture of poly (2,6-dimethyl-1,4-phenylene ether) and poly (2,6-dimethyl-1,4-phenylene ether) into which a sulfonic acid group is introduced. Examples of the polyphenylene sulfide resin (B) include a mixture of polyphenylene sulfide and sulfonated polyphenylene sulfide.

  About the polymer electrolyte composition of this invention, various additives, such as antioxidant, antioxidant, a heavy metal deactivator, a flame retardant, can be added as needed. The weight ratio of the polymer electrolyte composition of the present invention to the additive (electrolyte composition / additive) is preferably 80/20 to 99.999 / 0.001, more preferably 90/10 to 99.99. 99 / 0.01, more preferably 95/5 to 99.9 / 0.1.

  Next, a method for producing the polymer electrolyte composition of the present invention will be described. The polymer electrolyte composition of the present invention is obtained by mixing the components selected from the aforementioned components (A) to (H), but the method is not particularly limited, and a general polymer composition The mixing method of the product can be suitably applied.

  For example, a polymer compound (A) having an ion exchange group or a precursor polymer thereof, and components selected from the components (B) to (H) are thermally melted, and a kneading extruder, a lab plast mill, a kneading roll, The method of kneading with a Banbury mixer etc. is mentioned. In addition, the components selected from the components (B) to (H) are heat-melted in advance and kneaded with a kneading extruder, a lab plast mill, a kneading roll, a Banbury mixer or the like to obtain a mixture. The polymer compound (A) having an exchange group or a precursor polymer thereof can be similarly kneaded to obtain a final polymer electrolyte composition. The combination and order of kneading can be performed arbitrarily. In addition, when the precursor polymer is used in place of the polymer compound (A) having an ion exchange group, it is converted into a form having an ion exchange group by performing an alkali hydrolysis treatment and an acid treatment after kneading. The polymer electrolyte composition of the invention can be obtained.

  The kneading method at this time is achieved by a conventionally known technique such as a Brabender, a kneader, a Banbury mixer, and an extruder. In particular, it is preferable to use an extruder because the obtained polymer electrolyte composition can easily finely disperse other components in the polymer compound (A) having an ion exchange group.

  As a most preferred embodiment as a method for industrially easily obtaining the polymer electrolyte composition used in the present invention, an extruder for melting and kneading each of the above-mentioned components has a kneading block at an arbitrary position of a screw. It is a multi-screw extruder having two or more screws that can be incorporated, and the entire kneading block portion of the screw used is substantially (L / D) ≧ 1.5, more preferably (L / D) ≧ 5 (here L is the total length of the kneading block, D is the maximum outside diameter of the kneading block), and (π · D · N / h) ≧ 50 (where π = 3.14, D = screw outer diameter corresponding to the metering zone, N = screw rotation speed (rotation / second), h = groove depth of the metering zone]. These extruders have a first raw material supply port on the upstream side with respect to the flow direction of the raw material, a second raw material supply port on the downstream side, and if necessary, one more downstream on the downstream side of the second raw material supply port. The above raw material supply ports may be provided, and a vacuum vent port may be provided between these raw material supply ports as necessary.

  In addition, a method of removing the solvent after preparing a solution by mixing a solution of the polymer compound (A) having an ion exchange group or a precursor polymer thereof with each solution of the components (B) to (H) is also mentioned. It is done. Also in this case, when the precursor polymer solution was used in place of the polymer compound (A) solution having an ion exchange group, the solvent was removed, and then ion exchange was performed by alkali hydrolysis treatment and acid treatment. The polymer electrolyte composition of the present invention can be obtained by converting to a form having a group.

  The polymer electrolyte composition of the present invention can be obtained by the method as described above. In the present invention, at least a structure in which other components are finely dispersed in the polymer compound (A) having an ion exchange group is used. By having it, the effects of the present invention such as a longer life can be obtained. That is, in the polymer compound (A) having an ion exchange group, the particles composed of other components have a circular average particle diameter of 0.0001 μm to 1 μm, preferably 0.0001 μm to 0.8 μm, more preferably It is preferable to have a structure in which it is dispersed in a range of 0.0001 μm to 0.5 μm, particularly preferably 0.0001 μm to 0.3 μm. It is not always necessary to satisfy the above range in all regions of the composition, as long as 50 to 100% of the entire region of the composition satisfies the above range.

  Moreover, you may have a structure where (A) component has penetrated the inside of the dispersion particle which consists of another component. However, also at this time, the particle diameter of the dispersed particles is 0.0001 μm or more and 1 μm or less, preferably 0.0001 μm or more and 0.8 μm or less, more preferably 0.0001 μm or more and 0.5 μm or less, particularly preferably in terms of a circle-converted average particle diameter. The thickness is preferably 0.0001 μm or more and 0.3 μm or less from the viewpoint of extending the life.

  And it is suitable to have at least the fine dispersion structure as described above even in the proton exchange membrane described later.

  Such a finely dispersed structure can be controlled by the composition of the material, various conditions during processing, and the like. More specifically, the composition of the material includes the combination and amount ratio of each component, the use of a compatibilizing agent, and the type of solvent when using the solvent. Various conditions during processing include temperature conditions and stirring / kneading conditions, and the influence of screw design and screw rotation speed is particularly large during extrusion processing.

  In addition, the circle conversion average particle diameter in this invention is defined as follows. A thin slice is prepared from the polymer electrolyte composition or proton exchange membrane of the present invention, dyed with a dye such as ruthenium tetroxide by a conventional method, observed with a transmission electron microscope, and the average particle diameter of the dyed phase And take this value as the particle size. The average particle diameter at this time is the circle-converted diameter (the same area for each particle) calculated from this, after reading an arbitrary 20 × 20 μm field of view of a thin slice directly or after printing it on a photo from a negative, and reading it into an image analyzer. Number average value). However, if the staining boundary is unclear when inputting from the photograph to the image analysis apparatus, the photograph is traced and input to the image analysis apparatus using this figure.

  Next, a method for producing a proton exchange membrane made of the polymer electrolyte composition of the present invention will be described. The polymer electrolyte composition of the present invention can be formed into a membrane and used as a proton exchange membrane. The film forming means is not particularly limited, and a general polymer composition film forming method can be suitably applied. For example, known film forming methods such as calendar molding, press molding, T-die molding, and inflation molding can be used. Among these, T-die molding and inflation molding are preferable as methods for easily industrially obtaining a proton exchange membrane from the polymer electrolyte composition of the present invention. Inflation molding is particularly preferable from the viewpoint of obtaining a film having small anisotropy.

  Further, a polymer composition comprising a precursor of the polymer electrolyte composition of the present invention, for example, a precursor polymer of a polymer compound (A) having an ion exchange group, and a component selected from the components (B) to (H). After the product is formed using the above-described film forming method, the polymer electrolyte of the present invention is converted into a form having an ion exchange group by performing an appropriate post-treatment such as alkali hydrolysis treatment or acid treatment. A proton exchange membrane comprising the composition can also be obtained.

  Alternatively, the proton exchange membrane can be obtained by mixing each solution of the components (A) to (H) to prepare a solution, casting the solution, and then removing the solvent. As a casting method, a known coating method such as a method of casting into a petri dish, a gravure roll coater, a natural roll coater, a reverse roll coater, a knife coater and a dip coater can be used. The base material used for the casting method is a general polymer film, a metal foil, a substrate made of alumina, silicon or the like, a porous film obtained by stretching a PTFE film described in JP-A-8-162132, and JP-A-53- The fibrillated fibers disclosed in Japanese Patent No. 149881 and Japanese Patent Publication No. 63-61337 can be used. As a method for removing the solvent, methods such as heat treatment at room temperature to 200 ° C. and reduced pressure treatment can be used. When heat treatment is performed, the solvent can be removed by raising the temperature stepwise.

  Further, for example, instead of the solution of the polymer compound (A) having an ion exchange group, the solution of the precursor polymer is used, and the solutions of the components (B) to (H) are mixed to prepare a solution. After casting the solution, the solvent is removed, and then subjected to an appropriate post-treatment such as alkaline hydrolysis treatment or acid treatment to convert it into a form having an ion-exchange group, whereby the polymer electrolyte composition of the present invention is used. A proton exchange membrane can be obtained.

  In the production of the proton exchange membrane of the present invention, stretch orientation can be imparted by carrying out transverse uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching in combination with the above-described production method. Such stretching treatment is preferable because the mechanical properties of the proton exchange membrane of the present invention can be improved. This stretching treatment can be carried out in the state of a proton exchange membrane, or can be carried out in a state in which the proton exchange group is replaced with a metal salt such as sodium salt, potassium salt and calcium salt, ammonium salt or the like. When a polymer composition comprising a precursor polymer of the polymer compound (A) having an ion exchange group and a component selected from the components (B) to (H) is formed, the state immediately after the film formation However, it can also be carried out, and it can be carried out after the membrane is converted into a form having an ion exchange group by performing an appropriate post-treatment such as alkali hydrolysis treatment or acid treatment.

  The stretching treatment is preferably carried out at a magnification of 1.1 to 6.0 in the transverse (TD) direction and 1.0 to 6.0 in the longitudinal (MD) direction, more preferably 1. 1 to 3.0 times, 1.0 to 3.0 times in the vertical direction, more preferably 1.1 to 2.0 times in the horizontal direction, and 1.0 to 2.0 times in the vertical direction. The area stretch ratio is preferably 1.1 to 36 times.

  The proton exchange membrane of the present invention can have a structure in which at least two types of proton exchange membranes having different composition ratios are laminated. In the proton exchange membrane comprising the polymer electrolyte composition of the present invention, the higher the content of the resin other than the polymer compound (A) having an ion exchange group, the better the mechanical strength and the wet / dry dimensional change, and the higher the content of the ion exchange group. The higher the molecular compound (A) content, the better the electrical properties such as proton conductivity. By utilizing these characteristics, two or more types of proton exchange membranes with different composition ratios are designed and combined to form a single layer of a proton exchange membrane that excels in mechanical strength, wet and dry dimensional changes, and electrical properties. This can be realized more easily than in the case of a layer film.

  Although the number of layers to be laminated is not limited, since the manufacturing cost increases as the number of layers increases, about 2 to 10 layers are preferable. More preferably, it is 2-7 layers, and 3-5 layers are especially preferable. The composition ratio of the polymer compound (A) having an ion exchange group, polyphenylene sulfide resin (B), polyphenylene ether resin (C), polysulfone resin (D) and epoxy group-containing compound (F) in each layer is within the above range. Can be changed arbitrarily. Further, the thickness of each layer can be arbitrarily changed in consideration of characteristics.

  For example, in the case of a multilayer structure of three or more layers, the content ratio of the polymer compound (A) having an ion exchange group in the inner layer is made smaller than that of at least one of the surface layers, and the wet and dry dimensional changes in the inner layer When the thickness is suppressed, the thickness of the inner layer is preferably 5 to 90% of the total thickness, more preferably 7 to 80%, and particularly preferably 10 to 50%. In addition, when the content of the polymer compound (A) having an ion exchange group in the surface layer is made smaller than that in the inner layer and the change in the wet and dry dimensions is suppressed in the surface layer, the total thickness of the surface layer is A 5 to 50% ratio of the thickness is preferable, a 7 to 45% ratio is more preferable, and a 10 to 40% ratio is particularly preferable.

  In the production of the proton exchange membrane of the present invention, in addition to the above-described production method, reinforcement by adding a reinforcing material made of an inorganic material, an organic material, or an organic-inorganic hybrid material, reinforcement by crosslinking, and the like can be performed. The reinforcing material may be a short fiber material, a particulate material, or a flaky material. Further, a continuous support such as a porous film, a mesh, and a nonwoven fabric may be used. By carrying out the reinforcement by adding a reinforcing material to the proton exchange membrane of the present invention, the mechanical strength and the change in wet and dry dimensions can be easily improved. In particular, when a short fiber substance or the above-mentioned continuous support is used as a reinforcing material, the reinforcing effect is high.

  The reinforcing material may be added and mixed at the same time during melt-kneading, or may be laminated with the film after film formation.

  The inorganic material used as the reinforcing material is not particularly limited as long as it has a reinforcing effect. For example, glass fiber, carbon fiber, cellulose fiber, kaolin clay, kaolinite, halloysite, pyrophyllite, talc, montmorillonite, sericite, mica Amesite, bentonite, asbestos, zeolite, calcium carbonate, calcium silicate, diatomaceous earth, silica sand, iron ferrite, aluminum hydroxide, aluminum oxide, magnesium oxide, titanium oxide, zirconium oxide, graphite, fullerene, carbon nanotube, And carbon nanohorn. The organic material used as the reinforcing material is not particularly limited as long as it has a reinforcing effect. For example, polyphenylene sulfide, polyphenylene ether, polysulfone, polyether sulfone, polyether ether sulfone, polyether ketone, polyether ether ketone, polythioether. Sulfone, polythioether ether sulfone, polythioether ketone, polythioether ether ketone, polybenzimidazole, polybenzoxazole, polyoxadiazole, polybenzoxazinone, polyxylylene, polyphenylene, polythiophene, polypyrrole, polyaniline, polyacene, polycyanogen, polynaphthyridine , Polyphenylene sulfide sulfone, polyphenylene sulfone, polyimide, polyetherimide, poly Esterimide, polyamideimide, polyamide, aromatic polyamide, polystyrene, acrylonitrile-styrene resin, polystyrene-hydrogenated polybutadiene-polystyrene block copolymer, acrylonitrile-butadiene-styrene resin, polyester, polyarylate, liquid crystal polyester, polycarbonate, Examples thereof include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, polyvinylidene chloride, methacrylic resin, epoxy resin, phenol resin, melamine resin, urethane resin, cellulose, polyketone, polyacetal, polypropylene, and polyethylene. An organic-inorganic hybrid material can also be used as a reinforcing material, and examples thereof include an organic silicon polymer compound having a silsesquioxane structure or a siloxane structure such as POSS (Polyhedral Oligomeric Silsesquioxanes) or silicone rubber.

  Moreover, about the polymer electrolyte composition of this invention, a mechanical physical property can also be improved by heat-processing in 160 degreeC or more, for example in air or oxygen atmosphere.

  The equivalent mass EW of the proton exchange membrane produced according to the present invention (dry mass in grams of proton exchange membrane per equivalent of proton exchange groups) is preferably 250 or more and 2000 or less, more preferably 400 or more and 1500 or less, most preferably. Is 500 or more and 1200 or less. By using a proton conductive polymer with a lower EW, that is, a large proton exchange capacity, it exhibits excellent proton conductivity even under high temperature and low humidity conditions, and when used in a fuel cell, a high output can be obtained during operation. .

  The thickness of the proton exchange membrane produced according to the present invention is preferably 1 μm or more and 500 μm or less, more preferably 2 μm or more and 100 μm or less, and most preferably 5 μm or more and 50 μm or less.

  The change in wet and dry dimensions of the proton exchange membrane produced according to the present invention is preferably 0% to 100%, more preferably 0% to 50%, and most preferably 0% to 10%. The term “wet and dry dimensional change” as used herein refers to the ratio of the change in dimension when left in water at 80 ° C. for 1 hour with respect to the dimension when left at 25 ° C. and 20 RH% for 1 hour. The dimension is the length in the vertical direction or the horizontal direction of the proton exchange membrane, and both preferably satisfy the above range.

  A fuel cell was assembled as follows using the proton exchange membrane of the present invention, and durability was evaluated.

(Membrane electrode assembly)
When the proton exchange membrane obtained by the present invention is used for a polymer electrolyte fuel cell, it is used as a membrane electrode assembly (hereinafter abbreviated as “MEA”) in which two types of electrode catalyst layers are joined to an anode and a cathode on both sides of the membrane. Is done. A structure in which a pair of gas diffusion layers are bonded to the outer side of the electrode catalyst layer so as to face each other may be referred to as MEA.

  The electrode catalyst layer is composed of fine particles of a catalytic metal and a conductive agent supporting the catalyst metal, and a water repellent is included as necessary. The catalyst used for the electrode may be any metal that promotes the oxidation reaction of hydrogen and the reduction reaction by oxygen. Platinum, gold, silver, palladium, iridium, rhodium, ruthenium, iron, cobalt, nickel, chromium, tungsten , Manganese, vanadium, and alloys thereof, among which platinum is mainly used.

  As the MEA manufacturing method, for example, the following method is performed. First, a platinum-supported carbon serving as an electrode material is dispersed in a solution obtained by dissolving an ion exchange resin in a mixed solution of alcohol and water to form a paste. A certain amount of this is applied to a PTFE sheet and dried. Next, the application surface of the PTFE sheet faces each other, the proton exchange membrane of the present invention is sandwiched therebetween, and transfer bonding is performed by hot pressing at 100 ° C. to 200 ° C. to obtain an MEA.

(Fuel cell)
The MEA obtained above and, in some cases, a structure in which a pair of gas diffusion electrodes are opposed to each other via the MEA are further combined with components used for general solid polymer fuel cells such as a bipolar plate and a backing plate Thus, a polymer electrolyte fuel cell is constructed.

  A bipolar plate is a composite plate of graphite and resin or a metal plate that has grooves on the surface for flowing gas such as fuel and oxidant. It transmits electrons to an external load circuit. In addition, it has a function as a flow path for supplying fuel and oxidant to the vicinity of the electrode catalyst. A fuel cell is manufactured by inserting and stacking a plurality of MEAs between such bipolar plates.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to only these examples.

  The evaluation method and measurement method used in the present invention are as follows.

(Proton conductivity measurement)
A membrane sample is cut out in a wet state and the thickness T is measured. This is mounted on a two-terminal conductivity measuring cell that measures the conductivity in the film length direction having a width of 1 cm and a length of 5 cm. This cell is placed in ion exchange water at 80 ° C., and the resistance value R of the real component at a frequency of 10 kHz is measured by the AC impedance method, and the proton conductivity σ is derived from the following equation.

σ = L / (R × T × W)
σ: proton conductivity (S / cm)
T: Thickness (cm)
R: Resistance value (Ω)
L (= 5): film length (cm)
W (= 1): film width (cm)

(Fuel cell evaluation)
(1) Manufacture of fuel cell First, a proton exchange membrane is sandwiched between two gas diffusion electrodes coated on a mount and hot pressed at 180 ° C. and a pressure of 10 MPa to transfer and bond the gas diffusion electrode to the proton exchange membrane. To produce an MEA.

As the gas diffusion electrode, a platinum supported catalyst TEC10E40E (platinum supported rate 40 wt%) manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., a perfluorosulfonic acid polymer solution SS-700x / 05 (Asahi Kasei Co., Ltd., EW: 720, solvent composition (Mass ratio): ethanol / water = 50/50) and a solution concentrated to 12 wt% and ethanol were added, mixed and stirred to form an ink, which was applied onto a PTFE sheet, and then the atmosphere was 150 Use those dried and fixed at ℃. This gas diffusion electrode has a platinum loading of 0.4 mg / cm ² and a polymer loading of 0.5 mg / cm ² .

  Carbon paper or carbon cloth subjected to water repellent treatment is disposed on both sides of the MEA, and is incorporated into an evaluation cell and set in an evaluation apparatus. A single cell characteristic test is performed using hydrogen gas as a fuel and air gas as an oxidizing agent at a cell temperature of 100 ° C. and 0.1 MPa. A water bubbling method is used for gas humidification, and both hydrogen gas and air gas are humidified at 50 ° C. and supplied to the cell.

(2) Measurement of fluorine elution rate The waste water discharged together with the anode exhaust gas and the cathode exhaust gas during the single cell characteristic test is respectively collected for a predetermined time, and then weighed. The fluorine composite electrode 9609BNionplus is attached to a bench top type pH ion meter 920Aplus manufactured by Meditrial Co., Ltd., the fluorine ion concentration in the anode drainage and the cathode drainage is measured, and the fluorine elution rate G is derived from the following equation.

G = (Wa × Fa + Wc × Fc) / (T × A)
G: Fluorine elution rate (μg / Hr / cm ² )
Wa: Weight of anode wastewater collected and collected (g)
Fa: Fluorine ion concentration (ppm) in anode drainage
Wc: Weight of cathode drainage collected and collected (g)
Fc: Fluorine ion concentration in the cathode drainage (ppm)
T: Time for collecting and collecting wastewater (Hr)
A: MEA electrode area (cm ² )

(3) Measurement of cross leak amount A part of the cathode exhaust gas during the single cell characteristic test is introduced into a micro gas chromatograph Micro GC CP-4900 manufactured by GL Sciences, and the hydrogen gas concentration in the cathode exhaust gas is measured. From this, the hydrogen gas permeability is derived.

L = (X × V × T) × (5-U / 100) / (3 × A × P) × 10 ⁻⁸
L: Hydrogen gas permeability (ml × cm / cm ² / sec / Pa)
X: Hydrogen gas concentration (ppm) in cathode exhaust gas
V: Cathode gas flow rate (ml / min)
T: thickness of proton exchange membrane (cm)
U: Cathode gas utilization rate (%)
A: Hydrogen permeation area of proton exchange membrane (cm ² )
P: Hydrogen partial pressure difference between the cathode and anode (Pa)

The point in time when the hydrogen gas permeability during the short cell characteristic test reached 1.1 × 10 ⁻¹¹ (ml × cm / cm ² / sec / Pa) or more was defined as the cell life, and the test was terminated there.

[Example 1]
99 parts by weight of a precursor polymer (MI: 3.0, Ew after alkaline hydrolysis and acid treatment: 730) obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, and polyphenylene 0.5 parts by weight of sulfide (Sigma Aldrich Japan Co., Ltd., melt viscosity of 275 poise at 310 ° C.) and polyphenylene ether (2,6-xylenol obtained by oxidative polymerization, reduced viscosity of 0.51, glass transition Extruder using a twin screw extruder (ZSK-40; made by WERNER & PFLIDEERER, Germany) in which 0.5 part by weight (Tg is 209 ° C.) and a temperature of 280 to 310 ° C. and a screw rotation speed of 200 rpm was set. After being supplied from the first raw material supply port and melt-kneaded, it was melt-extruded using a T-die extruder to form a film having a thickness of 50 μm. This film was contacted in an aqueous solution in which potassium hydroxide (15% by mass) and dimethyl sulfoxide (30% by mass) were dissolved at 60 ° C. for 4 hours to perform an alkali hydrolysis treatment. Then, it was immersed in 60 degreeC water for 4 hours. Next, it was immersed in a 2N hydrochloric acid aqueous solution at 60 ° C. for 3 hours, then washed with ion-exchanged water and dried to obtain a proton exchange membrane (Ew: 736).

The proton conductivity of this proton exchange membrane was as high as 0.23 (S / cm). When this proton exchange membrane was evaluated for a fuel cell, the average value of the fluorine elution rate in the waste water from the start to 200 hours was as low as 0.038 (μg / Hr / cm ² ). The cell life reached 750 hours and was found to exhibit excellent durability.

[Example 2]
A proton exchange membrane (Ew: 737) was obtained in the same manner as in Example 1 except that polysulfone (manufactured by Sigma-Aldrich Japan Co., Ltd., number average molecular weight 26,000) was used instead of polyphenylene ether.

The proton conductivity of this proton exchange membrane was as high as 0.23 (S / cm). When this proton exchange membrane was evaluated for a fuel cell, the average value of the fluorine elution rate in the waste water from the start to 200 hours was as low as 0.049 (μg / Hr / cm ² ). The cell life reached 660 hours and was found to exhibit excellent durability.

[Comparative Example 1]
A precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F (MI: 3.0, Ew after alkali hydrolysis / acid treatment: 730) was used alone. Produced a proton exchange membrane (EW: 730, MI: 3.0) in the same manner as in Example 1.

The proton conductivity of this proton exchange membrane was as high as 0.23 (S / cm). When this proton exchange membrane was evaluated for a fuel cell, the average value of the fluorine elution rate in the waste water from the start to the cell life was 0.506 (μg / Hr / cm ² ), and the cell life was In less than 200 hours, sufficient durability was not obtained.

[Comparative Examples 2-35]
99 parts by weight of a precursor polymer (MI: 3.0, Ew after alkali hydrolysis / acid treatment: 730) obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F; and resin Extruder using a twin screw extruder (ZSK-40; made by WERNER & PFLEDERER, Germany) in which 0.5 parts by weight of X and 0.5 parts by weight of resin Y were set at a temperature of 280 to 310 ° C. and a screw rotation speed of 200 rpm After being supplied from the first raw material supply port and melt-kneaded, it was melt-extruded using a T-die extruder to form a film having a thickness of 50 μm. Here, as the resin X and the resin Y, the following resins were used, and various combinations were performed. Table 1 shows the correspondence between the various combinations, the example numbers, and the comparative example numbers.
Polyphenylene sulfide (indicated in the table as PPS): Sigma Aldrich Japan Co., Ltd., melt viscosity at 310 ° C. 275 poise Polyphenylene ether (same PPE): Reduction obtained by oxidative polymerization of 2,6-xylenol Viscosity 0.51, glass transition temperature (Tg) 209 ° C
Polysulfone (PSF): Sigma Aldrich Japan Co., Ltd., number average molecular weight 26,000
Polystyrene (PS): Sigma Aldrich Japan Co., Ltd., weight average molecular weight 230,000
Epoxy resin (Epoxy): Cresol novolac type epoxy resin N-660 manufactured by Dainippon Ink & Chemicals, Inc.
-Polyethersulfone (same PES): manufactured by Acros-Polyetherethersulfone (same PEES): manufactured by Sigma-Aldrich Japan Co., Ltd.-Polytetrafluoroethylene (same PTFE): FA-500 manufactured by Daikin Industries, Ltd.

  These films were contacted in an aqueous solution in which potassium hydroxide (15% by mass) and dimethyl sulfoxide (30% by mass) were dissolved at 60 ° C. for 4 hours to perform an alkali hydrolysis treatment. Then, it was immersed in 60 degreeC water for 4 hours. Next, it was immersed in a 2N hydrochloric acid aqueous solution at 60 ° C. for 3 hours, washed with ion-exchanged water and dried to obtain a proton exchange membrane.

  Fuel cell evaluation of various proton exchange membranes of the resin combinations shown in Table 1 was performed, and the average value of the elution rate of fluorine in waste water from the beginning to 200 hours (when the cell life is less than 200 hours) Asked. The results are shown in Table 2. As compared with Example 1 and Example 2, it was found that the average value of the fluorine elution rate was at least twice as large and good durability could not be obtained.

[Examples 3 to 12]
A proton exchange membrane was obtained in the same manner as in Examples 1 and 2 except that the composition ratio of Examples 1 and 2 was changed, and the fuel cell was evaluated. The results are shown in Table 3. In each case, not only the average value of the fluorine elution rate in the waste water from the start to 200 hours, but also the fluorine elution rate at about 500 hours showed a very low value, All of the cell lifetimes exceeded 1000 hours, and it was found that the cells had excellent durability.

  The changes of each example from Example 1 and 2 are described below.

[Example 3]
The composition ratio of Example 1 is 95 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 3 parts by weight of polyphenylene sulfide, and 2 parts by weight of polyphenylene ether. And changed.

[Example 4]
The composition ratio of Example 1 is 95 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 1 part by weight of polyphenylene sulfide, and 3 parts by weight of polyphenylene ether. And changed.

[Example 5]
Polyphenylene sulfide (melt viscosity (measured using a flow tester at 300 ° C., load 20 kgf / cm ² , L / D (L: orifice length, D: orifice inner diameter) = 10/1 after holding for 6 minutes) Is 50 Pa · s, the amount extracted with methylene chloride is 0.7 wt%, the amount of —SX group is 25 μmol / g), and the composition ratio of Example 1 is tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ). _{The amount} was changed to 90 parts by weight of a precursor polymer obtained from _2- SO ₂ F, 6 parts by weight of polyphenylene sulfide, and 2.5 parts by weight of polyphenylene ether.

[Example 6]
Polyphenylene sulfide (melt viscosity (measured using a flow tester at 300 ° C., load 20 kgf / cm ² , L / D (L: orifice length, D: orifice inner diameter) = 10/1 after holding for 6 minutes) Is 50 Pa · s, the amount extracted with methylene chloride is 0.7 wt%, the amount of —SX group is 25 μmol / g), and the composition ratio of Example 2 is tetrafluoroethylene and CF ₂ = CFO (CF ₂ ). _{The amount} was changed to 80 parts by weight of a precursor polymer obtained from _2- SO ₂ F, 15 parts by weight of polyphenylene sulfide, and 5 parts by weight of polysulfone.

[Example 7]
And using polyphenylene ether (reduced viscosity of 0.105, glass transition temperature of 165 ° C. obtained by oxidative polymerization of 2,6-xylenol and 3,3 ′, 5,5′-tetramethylbisphenol A) The composition ratio of Example 5 is 70 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 25 parts by weight of polyphenylene sulfide, and 5 parts by weight of polyphenylene ether. Changed to

[Example 8]
To the component of Example 5, 0.3 part by weight of a styrene-glycidyl methacrylate copolymer (weight average molecular weight 110,000) containing 5% by weight of glycidyl methacrylate was further added.

[Example 9]
The component of Example 8 has a structure of polystyrene-hydrogenated polybutadiene-polystyrene, the amount of bound styrene is 35% by weight, the number average molecular weight is 178,000, and 1,2-vinyl in the polybutadiene part before hydrogenation. 1.5 parts by weight of a hydrogenated block copolymer having a binding amount of 48% was further added.

[Example 10]
An epoxy resin (cresol novolac type epoxy resin N-660 manufactured by Dainippon Ink and Chemicals, Inc.) was further added to the components of Example 5, and the composition ratio was tetrafluoroethylene and CF ₂ = CFO (CF ₂ ). _The precursor polymer obtained from _2- SO ₂ F was changed to 90 parts by weight, polyphenylene sulfide 7 parts by weight, polyphenylene ether 1 part by weight, and epoxy resin 2 parts by weight.

[Example 11]
In Example 5, instead of polyphenylene ether, epoxy-modified polyphenylene ether (polyphenylene ether (obtained by oxidative polymerization of 2,6-xylenol and 3,3 ′, 5,5′-tetramethylbisphenol A having a reduced viscosity of 0) 105, a glass transition temperature of 165 ° C.) and an epoxy resin (a cresol novolak type epoxy resin N-660 manufactured by Dainippon Ink & Chemicals, Inc.) and a composition ratio. The amount was changed to 90 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 7 parts by weight of polyphenylene sulfide, and 3 parts by weight of epoxy-modified polyphenylene ether.

[Example 12]
In Example 4, a proton exchange membrane was obtained in the same manner as in Example 4 except that the screw rotation speed of the twin screw extruder was changed to 500 rpm.

  The average particle diameter in terms of circle of the dispersed particles in the proton exchange membrane was 0.9 μm, which was smaller than the average diameter in terms of circle of 2.0 μm of the dispersed particles in the proton exchange membrane of Example 4 having the same composition. As a result of fuel cell evaluation of this proton exchange membrane, it was found that the fluorine elution rate was lower than that of the proton exchange membrane of Example 4 and further excellent durability was exhibited.

[Example 13]
In Example 11, instead of using a T-die extruder, the film was melt-extruded using an annular die and then subjected to inflation molding to form a film having a thickness of 50 μm. At this time, the diameter of the annular die was 50 mm, the slit opening was 500 μm, the resin temperature was 250 ° C., the vertical draw ratio was 3.3 times, and the horizontal blow-up ratio was 3.0 times. When this film was cut into 7 cm square and freely shrunk in the plane direction at 230 ° C. for 10 minutes, shrinkage of almost the same degree was observed in both the vertical and horizontal directions. The film of Example 11 obtained using a T-die extruder showed a behavior in which a large shrinkage was observed only in the machine direction and the film was swollen in the transverse direction. It was confirmed to show. Further, this film had good orientation balance, little vertical and horizontal anisotropy, and better strength and reinforcing effect.

  This film was subjected to alkali hydrolysis treatment, acid treatment, water washing and drying in the same manner as in Example 11 to obtain a proton exchange membrane (Ew: 798) having a thickness of 50 μm.

The difference in the wet and dry dimensional change between the vertical direction and the horizontal direction of the proton exchange membrane is less than 2%, and the difference in the wet and dry dimensional change between the vertical and horizontal directions of the proton exchange membrane of Example 11 is about 20%. In comparison, it was confirmed that the anisotropy of the film was remarkably reduced. The proton conductivity of this proton exchange membrane was as high as 0.25 (S / cm). When this fuel cell was evaluated for the proton exchange membrane, the average value of the fluorine elution rate from the start to 200 hours was 0.010 (μg / Hr / cm ² ), which is very low for the proton exchange membrane of Example 11. Value, and proved to exhibit excellent durability.

[Example 14]
In Example 11, it was melt-extruded using a T-die extruder to form a 200 μm-thick film, and this film was formed in the MD direction at 120 ° C. using a biaxial simultaneous stretching apparatus (manufactured by Toyo Seiki Seisakusho) A proton exchange membrane having a thickness of 50 μm is obtained by performing 2.0 times, 2.0 times in the TD direction, and 4 times the area draw ratio, followed by alkali hydrolysis treatment, acid treatment, water washing and drying in the same manner as in Example 11. (Ew: 798) was obtained.

The puncture strength of this proton exchange membrane was measured using a handy compression tester (manufactured by Kato Tech Co., Ltd.) (probe radius 0.5 mm, puncture speed 2 mm / s, carried out in air at 25 ° C.). The proton exchange membrane increased approximately twice as much, confirming the improvement of membrane strength. The proton conductivity of this proton exchange membrane was as high as 0.26 (S / cm). When the fuel cell evaluation of this proton exchange membrane was performed, the average value of the fluorine elution rate in the waste water from the start to 200 hours was 0.009 (μg / Hr / cm ² ), and the proton exchange membrane of Example 11 Similarly, it was found to show a very low value and excellent durability.

[Example 15]
In Example 5, a film A was obtained by melt extrusion using a T-die extruder and forming into a 40 μm thick film. Further, the composition ratio of Example 5 was changed to 60 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 30 parts by weight of polyphenylene sulfide, and 10 parts of polyphenylene ether. The film was changed to parts by weight, and film B was formed by melt extrusion using a T-die extruder to form a film having a thickness of 5 μm.

  The film A sandwiched between two sheets of film B was thermocompression bonded at 290 ° C. and 10 MPa to form a film having a thickness of about 50 μm, and then the alkali hydrolysis treatment, acid treatment, water washing, It dried and the proton exchange membrane (Ew: 861) was obtained.

The dry / wet dimensional change of the proton exchange membrane was reduced to about 50% of the proton exchange membrane of Example 5, and it was confirmed that the wet / dry dimensional stability was improved. The proton conductivity of this proton exchange membrane was as high as 0.15 (S / cm). When the fuel cell evaluation of this proton exchange membrane was performed, the average value of the fluorine elution rate in the waste water from the start to 200 hours was 0.009 (μg / Hr / cm ² ), and the proton exchange membrane of Example 5 Similarly, it has been found that it exhibits a very low value and exhibits excellent durability.

[Example 16]
In Example 11, a film A was formed by melt extrusion using a T-die extruder to form a film having a thickness of 25 μm. Further, the composition ratio of Example 5 was changed to 50 parts by weight of a precursor polymer obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F, 35 parts by weight of polyphenylene sulfide and 15 parts of polyphenylene ether 15 The film was changed to parts by weight, and film B was formed by melt extrusion using a T-die extruder to form a film having a thickness of 5 μm.

  The film B sandwiched between two sheets of film A was thermocompression bonded at 290 ° C. and 10 MPa to form a film having a thickness of about 55 μm, and then the alkali hydrolysis treatment, acid treatment, water washing, Drying gave a proton exchange membrane (Ew: 847).

The lengthwise swelling rate of this proton exchange membrane in 25 ° C. water was reduced to about 45% of the proton exchange membrane of Example 11, and it was confirmed that the dimensional stability was improved under dry and wet conditions. The proton conductivity of this proton exchange membrane was as high as 0.20 (S / cm). When the fuel cell evaluation of this proton exchange membrane was performed, the average value of the fluorine elution rate in the waste water from the start to 200 hours was 0.009 (μg / Hr / cm ² ), and the proton exchange membrane of Example 11 Similarly, it has been found that it exhibits a very low value and exhibits excellent durability.

[Example 17]
In Example 5, a film A was formed by melt extrusion using a T-die extruder to form a film having a thickness of 25 μm.

  A 10 μm thick polyphenylene sulfide film (manufactured by Toray Industries, Inc.) was made porous to have a porosity of 70%. The film was sandwiched between two films A and thermocompression bonded at 290 ° C. and 10 MPa to a thickness of about 50 μm. Then, in the same manner as in Example 5, alkaline hydrolysis treatment, acid treatment, water washing and drying were performed to obtain a proton exchange membrane (Ew: 853).

The change in dry / wet dimensions of the proton exchange membrane was reduced to about 30% of that of the proton exchange membrane of Example 5, and it was confirmed that the wet / dry dimensional stability was improved. The proton conductivity of this proton exchange membrane was as high as 0.17 (S / cm). When the fuel cell evaluation of this proton exchange membrane was performed, the average value of the fluorine elution rate in the waste water from the start to 200 hours was 0.009 (μg / Hr / cm ² ), and the proton exchange membrane of Example 5 Similarly, it has been found that it exhibits a very low value and exhibits excellent durability.

[Example 18]
In Example 5, a film A was formed by melt extrusion using a T-die extruder to form a film having a thickness of 20 μm.

Further, in Example 5, 30% glass fiber-containing polyphenylene sulfide (manufactured by Dainippon Ink & Chemicals, Inc.) was used instead of polyphenylene sulfide, and the composition ratio was changed to tetrafluoroethylene and CF ₂ = CFO (CF ₂ ) A film of 10 μm thickness obtained by melt extrusion using a T-die extruder by changing the precursor polymer obtained from _2- SO ₂ F to 50 parts by weight, 45 parts by weight of polyphenylene sulfide, and 5 parts by weight of polyphenylene ether. Film B was formed into a film B.

  The film B sandwiched between two films A was thermocompression bonded at 290 ° C. and 10 MPa to form a film having a thickness of about 50 μm, and then the alkali hydrolysis treatment, acid treatment, water washing, Drying gave a proton exchange membrane (Ew: 921).

The change in dry / wet dimensions of the proton exchange membrane was reduced to about 30% of that of the proton exchange membrane of Example 5, and it was confirmed that the wet / dry dimensional stability was improved. The proton conductivity of this proton exchange membrane was as high as 0.17 (S / cm). When the fuel cell evaluation of this proton exchange membrane was performed, the average value of the fluorine elution rate in the waste water from the start to 200 hours was 0.009 (μg / Hr / cm ² ), and the proton exchange membrane of Example 5 Similarly, it was found to show a very low value and excellent durability.

[Comparative Examples 36 to 40]
Fuel cell evaluation was performed on proton exchange membranes obtained by impregnating various porous materials with perfluorocarbon sulfonic acid polymer. The results are also shown in Table 3. Although some of the perfluorocarbon sulfonic acid polymer content ratios decreased, the fluorine elution rate was lowered, but the cell life was at most about 400 hours, and it was found that none of them had good durability.

  A method for producing the proton exchange membrane of each comparative example will be briefly described below.

[Comparative Example 36]
A precursor polymer (MI: 3.0, Ew after alkaline hydrolysis and acid treatment: 730) obtained from tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F was converted to potassium hydroxide ( 15 mass%) and dimethyl sulfoxide (30 mass%) were dissolved in an aqueous solution at 60 ° C. for 4 hours for alkali hydrolysis treatment. Then, it was immersed in 60 degreeC water for 4 hours. Next, it was immersed in a 2N hydrochloric acid aqueous solution at 60 ° C. for 3 hours, washed with ion-exchanged water and dried to obtain a perfluorocarbon sulfonic acid polymer (Ew: 730). The obtained perfluorocarbonsulfonic acid polymer was placed in an autoclave together with an aqueous ethanol solution (water: ethanol = 50.0: 50.0 (weight ratio)), sealed, heated to 180 ° C. and held for 5 hours. Thereafter, the autoclave was naturally cooled to obtain a polymer solution C having a composition of perfluorocarbon sulfonic acid polymer: water: ethanol = 5.0: 47.5: 47.5 (weight ratio).

  A porous polyphenylene sulfide film (a 50 μm thick polyphenylene sulfide film (Toray Industries, Inc.) was made porous to a porosity of 60%) was sufficiently impregnated with the polymer solution C, and then placed in an oven. After drying at 1 ° C. for 1 hour, the temperature was raised to 160 ° C., and then heat treatment was further performed for 1 hour to obtain a proton exchange membrane (Ew: 1153).

[Comparative Example 37]
A proton exchange membrane (Ew: 1225) was obtained in the same manner as in Comparative Example 36, except that a polyimide porous body (manufactured by Ube Industries) was used instead of the porous polyphenylene sulfide film.

[Comparative Example 38]
Polysulfone (manufactured by Sigma-Aldrich Japan Co., Ltd., number average molecular weight 26,000) was added to dimethylformamide and stirred at 80 ° C. for 24 hours to obtain a polysulfone solution. This solution was cast on a glass plate to a thickness of about 50 μm using a bar coater, and then immediately immersed in water, which is a poor solvent, for 30 minutes to precipitate polysulfone to make it porous. Four sides of the obtained porous body were fixed, put in an oven, and dried at 120 ° C. for 24 hours to obtain a porous polysulfone film.

  A proton exchange membrane (Ew: 1010) was obtained in the same manner as in Comparative Example 36 except that this porous polysulfone film was used instead of the porous polyphenylene sulfide film.

[Comparative Example 39]
A porous polyethersulfone film was obtained in the same manner as in Comparative Example 38 except that polyethersulfone (manufactured by Across) was used instead of polysulfone. A proton exchange membrane (Ew: 1189) was obtained in the same manner as in Comparative Example 36 except that this film was used instead of the porous polyphenylene sulfide film.

[Comparative Example 40]
A proton exchange membrane (Ew: 1110) was carried out in the same manner as in Comparative Example 36 except that a polytetraethylene porous body (WP500-100 manufactured by Sumitomo Electric Industries, Ltd.) was used instead of the porous polyphenylene sulfide film. Obtained.

  The proton exchange membrane obtained from the polymer electrolyte composition of the present invention is a proton exchange membrane having high durability even at high temperatures, and is suitably used in the fields of ion exchange membranes and fuel cells. The proton exchange membrane obtained by the present invention can be used in various fuel cells including direct methanol fuel cells, water electrolysis, hydrohalic acid electrolysis, salt electrolysis, oxygen concentrators, humidity sensors, gas sensors and the like. is there.

Claims (26)

  A polymer electrolyte composition comprising a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), and a polyphenylene ether resin (C) and / or a polysulfone resin (D).   The polymer electrolyte composition according to claim 1, wherein the polyphenylene ether resin (C) is an epoxy-modified polyphenylene ether (E).   The polymer electrolyte composition according to claim 1 or 2, comprising a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), a polyphenylene ether resin (C), and an epoxy group-containing compound (F).   The polymer electrolyte composition according to claim 3, wherein the epoxy group-containing compound (F) is a homopolymer or copolymer (G) of an unsaturated monomer having an epoxy group.   The polymer electrolytic composition according to claim 4, wherein the epoxy group-containing compound (F) is a copolymer (G) containing an unsaturated monomer having an epoxy group and a styrene monomer.   The polymer electrolytic composition according to claim 3, wherein the epoxy group-containing compound (F) is an epoxy resin (H).   7. The polymer electrolyte composition according to claim 6, wherein the polymer-modified electrolyte composition is an epoxy-modified polyphenylene ether obtained by reacting at least part of the polyphenylene ether resin (C) and the epoxy resin (H). A polymer electrolyte composition containing E).   The polymer electrolyte composition according to any one of claims 1 to 7, wherein the polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group. The polymer electrolyte composition according to claim 8, wherein the perfluorocarbon polymer compound having an ion exchange group has a structural unit represented by the following general formula (1).
-[CF ₂ CX ¹ X ² ] _a- [CF ₂ -CF (-O- (CF ₂ -CF (CF ₂ X ³ )) _b -O _c- (CFR ¹ ) _d- (CFR ² ) _e- ( CF ₂ ) _f -X ⁴ )] _g- (1)
In the formula, X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, and a and g are 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, b is an integer of 0 or more and 8 or less, c is 0 or 1, d, e and f are each independently an integer of 0 or more and 6 or less (however, d + e + f is not equal to 0) , R ¹ and R ² are each independently a halogen element, a perfluoroalkyl group or a fluorochloroalkyl group having 1 to 10 carbon atoms, and X ⁴ is COOZ, SO ₃ Z, PO ₃ Z ₂ or PO ₃ HZ. is there. Here, Z is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or an amine (NH ₄ , NH ₃ R ₁ , NH ₂ R ₁ R ₂ , NHR ₁ R ₂ R ₃ , NR ₁ R ₂ R ₃ R ₄ R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups or arene groups.   Particles containing at least one resin selected from polyphenylene sulfide resin (B), polyphenylene ether resin (C) and polysulfone resin (D) are dispersed in the polymer compound (A) having an ion exchange group. The polymer electrolyte composition according to any one of claims 1 to 9, wherein the average particle diameter in terms of a circle of the particles is 1 µm or less.   Particles containing at least one resin selected from the polyphenylene sulfide resin (B), the polyphenylene ether resin (C) and the epoxy group-containing compound (F) are dispersed in the polymer compound (A) having an ion exchange group. The polymer electrolyte composition according to any one of claims 3 to 9, wherein the particle has a circle-converted average particle diameter of 1 µm or less.   The polymer electrolyte composition according to claim 10 or 11, wherein the region in which the particles are dispersed is 50 to 100% with respect to the entire region of the polymer electrolyte composition.   A proton exchange membrane comprising the polymer electrolyte composition according to any one of claims 1 to 12.   The polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group, and a polyphenylene sulfide resin (B) and a polyphenylene ether resin are used as a precursor of the perfluorocarbon polymer compound having an ion exchange group. A film obtained by subjecting (C) and / or polysulfone resin (D) to heat-blending and then extrusion-molding and then saponifying with an alkali and then acid-treating, has a film thickness of 5 to 200 μm Item 14. The proton exchange membrane according to Item 13.   The polymer compound (A) having an ion exchange group is a perfluorocarbon polymer compound having an ion exchange group, and a polyphenylene sulfide resin (B), a polyphenylene ether resin is used as a precursor of the perfluorocarbon polymer compound having an ion exchange group (C) and an epoxy group-containing compound (F) were heated, melted and mixed, and then the film obtained by extrusion molding was saponified with an alkali, and then manufactured by acid treatment. The film thickness was 5 to 200 μm. The proton exchange membrane according to claim 13.   The proton exchange membrane according to claim 14 or 15, wherein the extrusion molding is inflation molding.   The film was stretched 1.1 to 6.0 times in the transverse (TD) direction, 1.0 to 6.0 times in the longitudinal (MD) direction, and 1.1 to 36 times in area stretch ratio. The proton exchange membrane according to any one of the above.   The proton exchange membrane according to any one of claims 13 to 17, wherein at least two types of proton exchange membranes composed of polymer electrolyte compositions having different composition ratios are laminated.   The proton exchange membrane according to claim 18, wherein the polymer electrolyte composition comprises a polymer compound (A) having an ion exchange group, a polyphenylene sulfide resin (B), a polyphenylene ether resin (C), and an epoxy group-containing compound (F). .   At least three layers of proton exchange membranes made of at least two types of polymer electrolyte compositions having different contents of the polymer compound (A) having an ion exchange group are laminated, and the A is more than at least one of the surface layers. The proton exchange membrane according to claim 18 or 19, having an inner layer with a low content of 5 to 90% of the total layer thickness.   At least three layers of proton exchange membranes composed of at least two types of polymer electrolyte compositions having different contents of the polymer compound (A) having an ion exchange group are laminated, and the content of A in the surface layer is the inner layer. The proton exchange membrane according to claim 18 or 19, wherein the thickness of the surface layer is 5 to 50% of the total layer thickness.   The proton exchange membrane according to any one of claims 13 to 21, comprising a reinforcing material made of an inorganic material or an organic material.   The proton exchange membrane according to claim 22, wherein the reinforcing material is a short fiber substance.   The proton exchange membrane according to claim 22, wherein the reinforcing material is a continuous support.   The membrane electrode assembly which consists of a proton exchange membrane of Claims 13-24.   A polymer electrolyte fuel cell comprising the membrane electrode assembly according to claim 25.