JP4895563B2 - Reinforced polymer electrolyte membrane - Google Patents

Description

  The present invention relates to a polymer electrolyte membrane for a polymer electrolyte fuel cell.

A fuel cell obtains electric energy by electrochemical reaction from a fuel (hydrogen source) and an oxidant (oxygen) in the cell. In other words, the chemical energy of the fuel is directly converted into electrical energy. As the fuel source, pure hydrogen and other oils containing hydrogen elements, natural gas (methane, etc.), methanol, and the like can be used.
Since the fuel cell itself has no mechanical part, it generates less noise, and is characterized in that it can generate electric power semi-permanently by continuing to supply external fuel and oxidant.
Electrolytes are classified into liquid electrolytes and solid electrolytes. Among them, a polymer electrolyte fuel cell is one that uses a polymer electrolyte membrane as an electrolyte.
In particular, since the polymer electrolyte fuel cell operates at a low temperature as compared with others, it is expected as an alternative power source such as an automobile, a household cogeneration system, and a portable generator.

  The 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 resin membrane. The proton exchange resin membrane here is a material having a strong acidic group such as a sulfonic acid group or a carboxylic acid group in a polymer chain and a property of selectively transmitting protons. As such a proton exchange resin membrane, a perfluoro proton exchange resin membrane represented by Nafion (registered trademark, manufactured by DuPont, USA) 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 oxidant (for example, oxygen or air) is supplied to the gas diffusion electrode on the cathode side, and both electrodes are connected by an external circuit. It works by. Specifically, when hydrogen is used as the fuel, hydrogen is oxidized on the anode catalyst to generate protons, and these protons move through the proton conductive polymer in the anode catalyst layer and then move through the proton exchange resin membrane. And reaches the cathode catalyst through the proton conducting polymer in the cathode catalyst layer. On the other hand, electrons generated simultaneously with protons due to the 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. Sometimes electrical energy can be taken out. At this time, the proton exchange resin membrane also needs to play a role as a gas barrier. If the gas permeability of the proton exchange resin 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 (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 around 100 ° C., humidification at 60 ° C. (equivalent to humidity 20% RH)) assuming that the vehicle is driven in summer. 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 resin membrane, there is a problem that a pinhole is generated in the proton exchange resin membrane and a cross leak occurs. I could not get sex.

In order to solve this problem, a method of performing reinforcement by adding fibrillar PTFE (see Patent Documents 1 and 2), a method of performing reinforcement by a stretched PTFE porous membrane (see Patent Documents 3 and 4), and the like are performed. By these methods, the mechanical strength of the film is improved, so that it is difficult to physically make a pinhole. Also, compared to conventional perfluoroproton exchange resin membranes, pinholes are less likely to physically occur due to a reduction in the wet and dry dimensional change that swells in a wet state and shrinks in a dry state.

  On the other hand, chemical degradation in which the proton exchange resin is attacked and decomposed by hydroxy radicals by-produced in the anode catalyst or cathode catalyst has also been reported (see Non-Patent Document 1). PTFE as a reinforcing material in the above-mentioned reinforced membrane has excellent oxidation resistance and is not easily attacked by hydroxy radicals, but cannot capture hydroxy radicals. Therefore, the proton exchange resin constituting the reinforced membrane described above is decomposed when it is attacked for a long time by hydroxy radicals. That is, since the above-mentioned reinforced film has insufficient chemical resistance, sufficient durability cannot be obtained under the high temperature and low humidification conditions as described above.

Japanese Unexamined Patent Publication No. 53-149981 Japanese Patent Publication No. 63-61337 Japanese Patent Publication No. 5-75835 Japanese National Table No. 11-501964 A. B. LaConti, M. Hamdan and R. C. McDonald, in Handbook ofFuel Cells, H. A. Gasteiger, A. Lamm, Editors, Vol. 3, p.648, John Wiley & Sons, New York (2003)

  An object of the present invention is to provide a polymer electrolyte membrane that is excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability and has high durability even at high temperatures. Also provided is a highly durable fuel cell that does not generate cross-leakage even if it is operated for a long time under high temperature and low humidification conditions (for example, 60 ° C. humidification at an operating temperature of 100 ° C. (equivalent to a humidity of 20% RH)). The purpose is to do.

  The present inventors diligently studied to solve the above problems. As a result, by using a polyphenylene ether resin as a reinforcing material, not only is it excellent in oxidation resistance itself, but also plays a role of capturing hydroxyl radicals, thereby chemically degrading the proton exchange resin by hydroxy radicals. It was found that it can be suppressed. It has also been found that a polymer electrolyte membrane having excellent mechanical strength, heat resistance, and wet / dry dimensional stability can be obtained by finely phase-separating the polyphenylene ether resin into a proton exchange resin with a specific structure. It was. As a result, it is possible to provide a polymer electrolyte membrane having high durability even at high temperatures, and it can be operated for a long time under high temperature and low humidification conditions (for example, 60 ° C. humidification at an operating temperature of 100 ° C. (equivalent to a humidity of 20% RH)). The present inventors have found that a fuel cell having high durability that does not generate cross leak even if the test is performed can be provided. That is, the present invention is as follows.

(1) (a) a polymer electrolyte membrane having at least 30.00 to 99.99% by mass of proton exchange resin and (b) 0.01 to 70.00% by mass of polyphenylene ether resin, wherein the protons The exchange resin and the polyphenylene ether resin are phase-separated from each other, and the polyphenylene ether resin dispersed in one or more forms selected from a thread form, a fiber form, and a needle form is oriented perpendicular to the film thickness direction. A polymer electrolyte membrane characterized by that.
(2) The polymer electrolyte membrane according to (1), wherein the polyphenylene ether resin is randomly oriented in a plane perpendicular to the film thickness direction.
(3) The minor axis of the polyphenylene ether resin dispersed in one or more forms selected from thread form, fiber form, and needle form is 0.01 to 100 μm, and the ratio of major axis / minor axis is 1 to 10,000. The polymer electrolyte membrane according to (1) or (2), wherein

(4) The polyphenylene ether resin dispersed in one or more forms selected from a thread form, a fiber form, and a needle form has a structure having a minute nodule part and connected to each other (1) The polymer electrolyte membrane according to any one of to (3).
(5) The polymer electrolyte membrane according to any one of (1) to (4), wherein the size of the minute nodule portion is 0.01 to 10 μm.
(6) The proton exchange resin is a fluorine-based polymer electrolyte (1) to (1)
5. The polymer electrolyte membrane according to any one of 5).

(7) Dimensions when a film sample is left for 8 hours at 25 ° C. and 20% RH in each of the X-axis and Y-axis directions when the direction of the film plane is the X-axis and the direction perpendicular to the X-axis is the Y-axis The swelling ratio when wet, which is a ratio of dimensions when left in water at 80 ° C. for 1 hour, is 100 to 105%, and the ratio of the swelling ratio of the Y axis to the swelling ratio in the X axis direction is 0.00. 5. The polymer electrolyte membrane according to any one of (1) to (6), which is 5 to 1.5 and exhibits isotropic and wet dimensional stability.
(8) A polymer electrolyte laminate film comprising a laminate of two or more films having a proton exchange resin, wherein at least one film of the film is described in any one of (1) to (7) A polymer electrolyte laminate film, which is a polymer electrolyte film.

(9) A method for producing a polymer electrolyte membrane,
( A ) 30.00-99.99 mass% of proton exchange resin (component (a)) with respect to the total mass of component (a) and component (b),
( B ) Polyphenylene ether resin (component (b)) is 0.01-70.00 mass% with respect to the total mass of component (a) and component (b),
A polymer electrolyte membrane according to any one of ( 1) to (7) is formed by mixing with a liquid medium to form a cast liquid, and spraying the cast liquid onto a support. A method for producing a molecular electrolyte membrane.
(10) By supplying the cast liquid to the nozzle of the spray gun, generating a swirling flow of compressed gas, crushing the atomized cast liquid from the nozzle, and spraying it in a conical shape toward the support surface A method for producing a polymer electrolyte membrane according to (9), wherein a polymer electrolyte membrane is formed.

(11) A membrane / electrode assembly in which the polymer electrolyte membrane according to any one of (1) to (8) or the polymer electrolyte laminated membrane is held in close contact between an anode and a cathode, A membrane / electrode assembly, wherein the anode comprises an anode catalyst layer and has proton conductivity, and the cathode comprises a cathode catalyst layer and has proton conductivity.
(12) The polymer electrolyte according to any one of (1) to (8), wherein the polymer electrolyte membrane or polymer electrolyte laminate film is held in close contact between the anode catalyst layer and the cathode catalyst layer. The membrane / electrode assembly according to (11), wherein the membrane or the polymer electrolyte laminate membrane is formed only in a portion in contact with the edge of the anode catalyst layer and / or the cathode catalyst layer.
(13) The membrane / electrode assembly according to (11) or (12) is included, and an anode and a cathode are interposed between a polymer electrolyte membrane or a polymer electrolyte laminated membrane and an electron conductive material. A polymer electrolyte fuel cell characterized by being bonded to each other.
(14) The polymer electrolyte according to any one of (1) to (8), wherein the polymer electrolyte membrane or polymer electrolyte laminated film is held in close contact between the anode catalyst layer and the cathode catalyst layer. The membrane or the polymer electrolyte laminate film is formed only at at least one inlet portion and / or outlet portion selected from an anode gas inlet portion, an anode gas outlet portion, a cathode gas inlet portion, and an outlet portion. The polymer electrolyte fuel cell according to (13).

  The polymer electrolyte membrane of the present invention is excellent in chemical stability, mechanical strength, heat resistance, and dry / wet dimensional stability. In addition, by using the polymer electrolyte membrane of the present invention, even if it is operated for a long period of time under high temperature and low humidification conditions (for example, 60 ° C. humidification at an operating temperature of 100 ° C. (equivalent to a humidity of 20% RH)) It is possible to provide a fuel cell having high durability that does not generate odor.

The present invention is described in detail below.
The polymer electrolyte membrane of the present invention comprises (a) 30.00 to 99.99% by mass of proton exchange resin and (b) 0.01 to 70.00% by mass of polyphenylene ether resin.

  Proton exchange resins include polyethersulfone resin, polyetheretherketone resin, phenol-formaldehyde resin, polystyrene resin, polytrifluorostyrene resin, trifluorostyrene resin, poly (2,3-diphenyl-1,4-phenylene oxide) ) Resin, poly (allyl ether ketone) resin, poly (allyl ether sulfone) resin, poly (phenylquinosan phosphorus) resin, poly (benzylsilane) resin, polystyrene-graft-ethylenetetrafluoroethylene resin, polystyrene-graft-polyfluoride Polymers with a hydrocarbon moiety, such as vinylidene resin, polystyrene-graft-tetrafluoroethylene resin, polyimide resin, and polybenzimidazole resin, which have sulfonic acid groups or carboxylic acid groups introduced. Applicable but, the most preferred are fluorine-based polymer electrolytes as shown below.

The fluorine-based polymer electrolyte is not particularly limited, but Nafion (registered trademark; manufactured by DuPont, USA), Aciplex (registered trademark; manufactured by Asahi Kasei Chemicals, Japan), Flemion (registered trademark; Asahi Glass, Japan) A typical example is a perfluorocarbon polymer having a proton exchange group represented by the following chemical formula (1) represented by the following chemical formula (1). _{^{[CF 2 CX 1 X 2]}} a - [CF 2 -CF (-O- (CF 2 -CF (CF 2 X 3)) b -
_{^{Oc - (CFR 1) d -}} (CFR 2) e - (CF 2) f -X 4)] g
... (1)
Wherein X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, 0 ≦ b ≦ 8, c is 0 or 1, d, e and f are each independently a number in the range of 0-6 (where d + e + f is not equal to 0), R ¹ and R ² are each independently a halogen element, C 4-10 perfluoroalkyl group or fluorochloroalkyl group, X ⁴ is —COOH, —SO ₃ H, —PO ₃ H ₂ , —PO ₃ HZ (Z is a hydrogen atom, metal atom (Na , K, Ca, etc.) or amines (NH ₄ , NH ₃ R, NH ₂ R ₂ , NHR ₃ , NR ₄ (R is an alkyl group or arene group))

Among these, a perfluorocarbon polymer represented by the following chemical formula (2) or (3) is preferable.
_{[CF 2 CF 2] a -} [CF 2 -CF (-O- (CF 2 -CF (CF 3)) b -O-
(CF ₂ ) _f −X ⁴ )] _g (2)
(Where 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, 1 ≦ b ≦ 3, 1 ≦ f ≦ 8, and X ⁴ represents —COOH, —SO ₃ H, —PO ₃ H ₂ or — PO ₃ H.)
_{[CF 2 CF 2] a -} [CF 2 -CF (-O- (CF 2) f -X 4)] g
... (3)
(Where 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, 1 ≦ f ≦ 8, and X ⁴ is —COOH, —SO ₃ H, —PO ₃ H ₂ or —PO ₃ H. )
The perfluorocarbon polymer as described above may be a copolymer further including units derived from a perfluoroolefin such as hexafluoropropylene or chlorotrifluoroethylene, or a comonomer such as perfluoroalkyl vinyl ether.

A method for producing a fluorine-based polymer electrolyte used in the present invention is described in, for example, US Pat. No. 5,281,
No. 680, Japanese Patent Laid-Open No. 7-252322, US Pat. No. 5,608,022
It is described in the specification.
The content of the (a) proton exchange resin in the polymer electrolyte membrane of the present invention is 30.00 to 99.99% by mass, preferably 40.0 to 99.9% by mass, more preferably 50 to 99% by mass. %, More preferably 60 to 90% by mass, most preferably 65 to 80% by mass. (A) By setting the content of the proton exchange resin in the above range (30.00 to 99.99% by mass), a polymer electrolyte membrane having high durability while maintaining good proton conductivity is obtained. Obtainable.

  The (b) polyphenylene ether resin used in the polymer electrolyte membrane of the present invention is not particularly limited, and examples thereof include poly (2,6-dimethyl-1,4-phenylene) ether and poly (2-methyl-6-ethyl-). 1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2-methyl-6-n-propyl-1,4-phenylene) ether, poly (2-ethyl-) 6-n-propyl-1,4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, poly (2-methyl-6-i-propyl-1,4- Phenylene) ether, poly (2-ethyl-6-i-propyl-1,4-phenylene) ether, poly (2,6-di-i-propyl-1,4-phenylene) ether, poly (2- Til-6-phenyl-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2-methyl-6-chloro-1,4-phenylene) ether, poly ( 2-methyl-6-hydroxyethyl-1,4-phenylene) ether, poly (2-methyl-6-chloroethyl-1,4-phenylene) ether, poly (2-methyl-6-methoxy-1,4-phenylene) ) Ether, poly (2-methyl-1,4-phenylene) ether, poly (-1,4-phenylene) ether, poly (2,6-di (p-fluorophenyl) -1,4-phenylene) ether, And polyphenylene ether homopolymers. Among these, poly (2,6-dimethyl-1,4-phenylene) ether represented by the following chemical formula (4) is an industrially important polyphenylene ether resin, manufactured by Asahi Kasei Chemicals Corporation and GE Plastics ( A typical example is a product manufactured by Co., Ltd.

（式中、ｎは１以上の整数）

(Where n is an integer of 1 or more)

The polyphenylene ether resin (b) used in the polymer electrolyte membrane of the present invention may be a polyphenylene ether copolymer, a copolymer of 2,6-dimethylphenol and o-cresol, 2,6-dimethylphenol and 2 This corresponds to a polyphenylene ether copolymer mainly composed of a polyphenylene ether structure, such as a copolymer with 3,6-trimethylphenol.
In addition, as the (b) polyphenylene ether resin used in the polymer electrolyte membrane of the present invention, other various phenylene ethers that have been proposed to exist in the polyphenylene ether are proposed unless they are contrary to the spirit of the present invention. It does not matter if the unit contains it. For example, the following heterogeneous structure can be given as an example of polyphenylene ether derived from a monomer mainly composed of 2,6-dimethylphenol. Examples of the terminal structure of the polyphenylene ether include aminoalkyl-substituted terminal groups described in JP-B-7-47634 represented by the following chemical formula (α) and 4-hydroxybiphenyl represented by the following chemical formula (β). Examples include end groups.

（式中、Ｒ_３，Ｒ_４は各々独立に１〜２０の炭化水素基を示す）

(Wherein R ₃ and R ₄ each independently represent 1 to 20 hydrocarbon groups)

  As the heterogeneous structure in the polymer chain, 2- (dialkylaminomethyl) -6-6 described in JP-A-1-297428 and JP-A-63-301222 as shown by the following chemical formula (γ) Examples thereof include a methylphenylene ether unit and a 2- (N-alkyl-N-phenyl-aminomethyl) -6-methylphenylene ether unit represented by the following chemical formula (δ).

（式中、Ｒ_３，Ｒ_４は各々独立に１〜２０の炭化水素基を示す）

(Wherein R ₃ and R ₄ each independently represent 1 to 20 hydrocarbon groups)

（式中、Ｒ_５は炭素数１〜２０のアルキル基、アルカノール基を示し、Ｒ_６は水素、炭素数１〜１０の置換あるいは非置換アルキル基を示し、ｍは該フェニル環の置換基の数で１から５の整数である）

(In the formula, R ₅ represents an alkyl group having 1 to 20 carbon atoms and an alkanol group, R ₆ represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and m represents a substituent of the phenyl ring. (It is an integer from 1 to 5)

  Furthermore, it is a polyphenylene ether having a special structure, for example, a quinone-bonded polyphenylene ether represented by the following chemical formula (ε) described in JP-B-61-20575, JP-B-55-46015 and JP-A-62-39628. It may be a bifunctional polyphenylene ether represented by the following chemical formula (ζ) described in the publication.

（式中、ｐ、ｑは連鎖の数で１以上の整数である）

(In the formula, p and q are the number of chains and an integer of 1 or more)

（式中、ｘ、ｙは連鎖の数で０または１以上の整数であるが同時に０ではない）

(In the formula, x and y are the number of chains, which is 0 or an integer of 1 or more, but are not 0 at the same time)

  The content of the (b) polyphenylene ether resin in the polymer electrolyte membrane of the present invention is 0.01 to 70.00% by mass, preferably 0.1 to 60.0% by mass, more preferably 1 to 50% by mass. %, More preferably 10 to 40% by mass, and most preferably 20 to 35% by mass. By setting the content of the polyphenylene ether resin in the above range (0.01 to 70.00% by mass), it is possible to obtain a polymer electrolyte membrane having high durability while maintaining good proton conductivity. it can.

  In the polymer electrolyte membrane of the present invention, the proton exchange resin and the polyphenylene ether resin are phase-separated from each other. The phase separation here refers not only to a state where the proton exchange resin and the polyphenylene ether resin are not completely compatible, but also to a state where they are partially compatible. By forming such a phase separation state, a polymer electrolyte membrane excellent in chemical stability and heat resistance can be obtained.

  In the polymer electrolyte membrane of the present invention, the polyphenylene ether resin dispersed in one or more forms selected from a thread form, a fiber form, and a needle form is oriented perpendicular to the film thickness direction. . The term “orientation” as used herein refers to Polymer Dictionary (4th edition), edited by the Society of Polymer Science, Asakura Shoten Co. As described in 522-524 (Showa 51), it refers to a state in which structural units constituting a substance are preferentially arranged in a specific direction of the substance. Specific examples of such a case include FIGS. 1 to 3. Thus, when the polyphenylene ether resin is oriented perpendicularly to the film thickness direction, a polymer electrolyte membrane excellent in mechanical strength and dry / wet dimensional stability can be obtained.

  Furthermore, in the polymer electrolyte membrane of the present invention, it is preferable that the polyphenylene ether resin is randomly oriented in a plane perpendicular to the film thickness direction. Thus, the polyphenylene ether resin isotropically oriented, so that the polymer electrolyte membrane of the present invention exhibits isotropic wet-wet dimensional stability in any direction on the plane of the membrane. The wet and dry dimensional stability is a ratio of the swell ratio when left for 1 hour in water at 80 ° C. to the dimension when the membrane sample is left for 8 hours at 25 ° C. and 20% RH. %, Preferably 100-110%, more preferably 100-105%, most preferably 100-101%. In addition, the isotropic wet-wet dimensional stability shown here means that when the direction of the film plane is the X axis and the direction perpendicular thereto is the Y axis, the Y with respect to the swelling rate in the X axis direction The ratio of the swelling ratio of the shaft is 0.5 to 1.5, preferably 0.8 to 1.2, more preferably 0.9 to 1.1, and most preferably 0.95 to 1.05. Point to.

  The oriented polyphenylene ether resin is desirably dispersed in the form of, for example, a thread, a fiber, or a needle. The minor axis (in the film thickness direction) of the dispersed polyphenylene ether resin is preferably 0.01 to 100 μm, more preferably 0.01 to 30 μm, still more preferably 0.01 to 10 μm, and most preferably. Is 0.1 to 5 μm. Further, the aspect ratio, which is the ratio of the major axis / minor axis of the dispersed polyphenylene ether resin, is preferably 1 to 10000, more preferably 2 to 5000, still more preferably 5 to 3000, and most preferably. 10 to 1000. In addition, the black-stained portion in FIGS. 1 to 3 is a polyphenylene ether resin, and the transparent portion is a fluoropolymer electrolyte. Further, the polyphenylene ether resin as described above is preferably uniform in the film both in the film thickness direction and in the film plane direction. In the polymer electrolyte membrane having membrane cross sections as shown in FIGS. 1 to 3, the polyphenylene ether resin can be regarded as being uniformly dispersed in the membrane.

  In some cases, the polyphenylene ether resin dispersed in the form of threads, fibers, and needles may be connected to each other with the polyphenylene ether. As a specific example, a fine structure including a large number of minute nodules as shown in FIG. Structure is mentioned. Although it does not specifically limit as a magnitude | size of the minute nodule said here, It is preferable that it is 0.01-10 micrometers, More preferably, it is 0.02-8 micrometers, More preferably, it is 0.05-5 micrometers, Most preferably, it is 0.8. 1 to 2 μm. The black-stained portion in FIG. 2 is a polyphenylene ether resin, and the transparent portion is a fluoropolymer electrolyte. The number density of the minute nodules is preferably 1 to 1000, more preferably 2 to 500, still more preferably 5 to 300, and most preferably 10 to 10 per 1 μm × 1 μm membrane cross section. 100.

Further, the polymer electrolyte membrane of the present invention as described above is used as a reinforcing layer, and laminated with a film made of the proton exchange resin without containing the polyphenylene ether resin (hereinafter referred to as an unreinforced layer). You may use as a polymer electrolyte laminated film made into the laminated body. For example, in the case of 2 layers, a reinforcing layer / unreinforced layer, in the case of 3 layers, a reinforced layer / unreinforced layer / reinforced layer, an unreinforced layer / reinforced layer / unreinforced layer, and in the case of 4 layers, a reinforced layer / Unreinforced layer / Reinforced layer / Unreinforced layer, Unreinforced layer / Reinforced layer / Unreinforced layer / Reinforced layer In case of 5 layers, Reinforced layer / Unreinforced layer / Reinforced layer / Unreinforced layer / Reinforced layer, None Examples of the configuration include a reinforcing layer / a reinforcing layer / an unreinforced layer / a reinforcing layer / an unreinforced layer. When three or more layers are laminated, a reinforcing layer and a non-reinforcing layer having different compositions and physical properties may be used. For example, the configuration of reinforcing layer 1 / non-reinforcing layer 1 / reinforcing layer 2 / non-reinforcing layer 2 / reinforcing layer 3, non-reinforcing layer 1 / reinforcing layer 1 / non-reinforcing layer 2 / reinforcing layer 2 / non-reinforcing layer 3, etc. it can.
Furthermore, the polymer electrolyte membrane of the present invention as described above may be formed only on a part of the polymer electrolyte membrane.

  The proton exchange capacity of the polymer electrolyte membrane or polymer electrolyte laminated membrane of the present invention is not particularly limited, but is preferably 0.5 to 4.0 milliequivalents per gram, more preferably 0.8 to 4.0 milliequivalents. Most preferably, it is 0.9 to 1.5 milliequivalents. Using a polymer electrolyte membrane or polymer electrolyte laminated membrane with a larger proton exchange capacity shows higher proton conductivity under high temperature and low humidification conditions, and when used in a fuel cell, obtains higher output during operation. Can do.

The proton exchange capacity can be measured by the following method. First, the polymer electrolyte membrane or polymer electrolyte laminated membrane cut out to about 10 cm ^{2 is} vacuum-dried at 110 ° C. to obtain the dry weight W (g). This membrane is immersed in 50 ml of a 25 ° C. saturated NaCl aqueous solution to release H ⁺ , neutralized with 0.01 N sodium hydroxide aqueous solution using phenolphthalein as an indicator, and the equivalent amount of NaOH required for neutralization. Obtain M (millimeter equivalent). The value obtained by dividing M thus determined by W is the proton exchange capacity (milli equivalent / g). The value obtained by dividing W by M and multiplying by 1000 is the equivalent mass EW, which is the dry mass in grams per equivalent of proton exchange groups.

  The thickness of the polymer electrolyte membrane or polymer electrolyte laminate film of the present invention is not limited, but is preferably 1 to 500 μm, more preferably 2 to 150 μm, still more preferably 5 to 75 μm, and most preferably 5 to 50 μm. is there. The thicker the film thickness, the better the durability, but the worse the initial characteristics. Therefore, it is preferable to set the film thickness within the above range (1 to 500 μm).

  The polymer electrolyte membrane or polymer electrolyte laminate film of the present invention comprises a heat-resistant polymer such as polybenzimidazole, polyimide, polyamideimide, polypyridine, polypyrimidine, polyimidazole, polyvinylpyridine, polyvinylimidazole, polyaniline, and polyphenylene sulfide. May be included. Among these, the addition of polybenzimidazole and polyphenylene sulfide is preferable because the oxidation resistance can be improved. The content of the heat-resistant polymer in the polymer electrolyte membrane or polymer electrolyte laminate film of the present invention is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and most preferably 1 to 5%. It is below mass%. The heat-resistant polymer may be present in the form of particles in the polymer electrolyte membrane or polymer electrolyte laminate film of the present invention. In this case, the average particle size (50% volume basis) is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

The polymer electrolyte membrane or polymer electrolyte laminated membrane of the present invention is reinforced by the addition of inorganic particles (Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO _2, etc.) (Japanese Patent Laid-open No. Hei 6-1111827,
Japanese Patent Laid-Open No. 9-219206 and U.S. Pat. No. 5,523,181), reinforcement by crosslinking (see Japanese Laid-Open Patent Publication No. 2000-188013), silica in the film using sol-gel reaction ((KA Mauritz, RF Storey and CK Jones, in Multiphase Polymer Materials: Blends and Ionomers, LA Utracki and RA Weiss, Editors, ACS Symposium Series No. 395, p. 401, American Chemical Society, Washington , DC (1989)) may be used for reinforcement.

(Production example of the polymer electrolyte membrane of the present invention)
Although the manufacturing method of the polymer electrolyte membrane of this invention is demonstrated below, it is not limited to the manufacturing method illustrated below.
The polymer electrolyte membrane of the present invention can be produced, for example, by the following method.
A method for producing a polymer electrolyte membrane, comprising:
(A) Proton exchange resin is 30.00-99.99 mass% with respect to the total mass of component (a) and component (b), and (b) Polyphenylene ether resin is the sum of component (a) and component (b). 0.01 to 70.00 mass% with respect to mass,
A cast liquid mixed with a liquid medium is used, and the cast liquid is cast on a support to form a coating film, and at the same time, the liquid medium is removed to form a polymer electrolyte membrane.

  The cast liquid is, for example, an emulsion (in which a liquid particle is dispersed as a colloidal particle or a coarser particle in the liquid to form a milky state), a suspension (a solid particle in the liquid is colloidal particles or a microscope). Such as particles dispersed as visible particles), colloidal liquid (macromolecules dispersed), or micellar liquid (a lyophilic colloidal dispersion system formed by the intermolecular force of many small molecules). These composite systems may also be used.

The concentration of the (a) proton exchange resin in the casting solution is not limited, but is preferably 0.01 to 40% by mass, more preferably 0.1 to 20% by mass, most preferably based on the total mass of the casting solution. 0.5-8 mass%.
The concentration of the (b) polyphenylene ether resin in the casting solution is not limited, but is preferably 0.01 to 40% by mass, more preferably 0.1 to 20% by mass, most preferably based on the total mass of the casting solution. Preferably it is 0.5-4 mass%.

The mass ratio of the proton exchange resin (a) to the polyphenylene ether resin (b) (proton exchange resin (a): polyphenylene ether resin (b)) in the casting solution is 99.99: 0.01-30. 00: 70.00, preferably 99.9: 0.1-40.0: 60.0, more preferably 99: 1-50: 50, even more preferably 90: 10-60: 40. Most preferably, it is 80: 20-65: 35.
The concentration of the liquid medium in the casting liquid is not limited, but is preferably 20 to 99.98% by mass, more preferably 60 to 99.8% by mass, and most preferably 88 to 99% by mass with respect to the total mass of the casting liquid. preferable.

Although it does not specifically limit as a liquid medium in a casting liquid, It is preferable that it is a mixed solvent of a protic solvent and an aprotic solvent. The proton solvent mentioned here is a solvent having a functional group capable of emitting protons, and examples thereof include water, alcohols (methanol, ethanol, propanol, isopropanol, etc.), and phenols. Although it does not specifically limit as a quantity of a proton solvent, It is preferable that it is 1-99 mass% with respect to the total mass of a casting liquid, More preferably, it is 10-97 mass%, Most preferably, it is 30-85 mass%. is there.
These proton solvents may be used alone or in combination of two or more. In particular, a mixed solvent of water and alcohol is preferably used, and water / ethanol = 3/1 to 1/3 (
It is more preferable to use a mixed solvent of (volume ratio) and water / isopropanol = 3/1 to 1/3 (volume ratio).

  The liquid medium in the casting liquid preferably further contains an aprotic solvent. Here, the aprotic solvent is a solvent other than the above-mentioned proton solvent, and examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetone, methyl ethyl ketone, toluene, chloroform. And carbon tetrachloride. These aprotic solvents may be used alone or in combination of two or more. Of these, N, N-dimethylacetamide, N-methylpyrrolidone, toluene and chloroform are particularly preferred. Although the amount of the aprotic solvent is not particularly limited, it is preferably 0.98 to 98.98% by mass, more preferably 2.8 to 89.8% by mass, most preferably based on the total mass of the casting liquid. Is 3 to 69% by mass.

By using such a casting solution, it becomes possible to produce a polymer electrolyte membrane in which a polyphenylene ether resin is finely phase-separated in a proton exchange resin, and has high durability while maintaining good proton conductivity. A polymer electrolyte membrane can be obtained.
For example, the casting solution includes a polymer solution in which polyphenylene ether resin (b) is dissolved in an aprotic solvent such as toluene (hereinafter referred to as “preliminary solution A”), and proton exchange resin (a) in a proton solvent. The obtained polymer solution (hereinafter referred to as “pre-stage solution B”) is added and stirred.

The production method of the polyphenylene ether resin (b) is not particularly limited, and any known monomer and known polymerization method, in particular, many synthesis methods using a phenolic compound as a monomer can be used. For example, many production methods have been proposed including Japanese Patent Publication No. 36-18692, U.S. Pat. Nos. 3,306,875, 3,344,116 and 3,342,466. In these known publications, the industrially most important monomer is 2,6-dimethylphenol.
The weight average molecular weight of the polyphenylene ether resin (b) is not limited, but is preferably 10,000 to 1,000,000, more preferably 20,000 to 100,000, and most preferably 50,000 to 100,000. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

Moreover, you may use an intrinsic viscosity (dl / g) as a parameter | index instead of such a weight average molecular weight. Intrinsic viscosity includes the viscosity ηp (mPa · s) of the polymer solution obtained by dissolving the polyphenylene ether resin (b) in chloroform, the viscosity ηs (mPa · s) of chloroform, and the concentration Cp (g / dL) of the polymer solution. ) From the following equation. The viscosity here is, for example, a value measured with an Ubbelohde viscosity tube at 30 ° C.
Intrinsic viscosity = ln (ηp / ηs) / Cp
(In the formula, ln represents a natural logarithm.)
The intrinsic viscosity of the polyphenylene ether resin (b) is preferably in the range of 0.05 to 1.0 dl / g when a 0.5 g / dl polymer solution is used, and more preferably 0.06 to 0.70 dl / g. It is more preferable to use the thing of the range of g.

The pre-stage solution A can be obtained by a method in which such a (b) polyphenylene ether resin is placed in an aprotic solvent such as toluene or chloroform and heat-treated at 20 to 90 ° C. for 10 minutes to 100 hours. The content of the (b) polyphenylene ether resin in the pre-stage solution A is preferably 0.01 to 50% by mass, more preferably 0.1 to 30% by mass, most preferably based on the mass of the pre-stage solution A. Is 1-10 mass%.
A perfluorocarbon polymer having a proton exchange group, which is a representative example of the proton exchange resin contained in the pre-stage solution B, is obtained by polymerizing a precursor polymer represented by the following chemical formula (5) by the following method, It can be produced by decomposition and acid treatment.
_{^{[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
... (5)
(Wherein X ¹ , X ² and X ³ are each independently a halogen element or a C 1-3 perfluoroalkyl group, 0 ≦ a <1, 0 <g ≦ 1, a + g = 1, b is 0 to 8, c is 0 or 1, d, e and f are each independently a number from 0 to 6 (where d + e + f is not equal to 0), R ¹ and R ² are each independently a halogen element , A C 1-10 perfluoroalkyl group or fluorochloroalkyl group, X ⁵ is —COOR ³ , —COR ⁴ or —SO ₂ R ⁴ (R ³ is a C 1-3 alkyl group (fluorinated Not)), R ⁴ is a halogen element))

The precursor polymer represented by the chemical formula (5) is produced by copolymerizing a fluorinated olefin and a vinyl fluoride compound. Specific examples of the fluorinated olefin include CF ₂ = CF ₂ , CF ₂ = CFCl, CF ₂ = CCl _{2 and the} like. 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 F (OCF 2 CF (CF 3)) z - (CF 2) z-1 -SO 2 F, CF 2 = CFO (CF 2) z -CO 2 R, CF _{2 = 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 (Z represents an integer of 1 to 8, R represents an alkyl group having 1 to 3 carbon atoms (not substituted with fluorine)), and the like.

As a method for polymerizing such a 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 tetrafluoroethylene gas to perform polymerization. Polymerization is performed without using a solvent such as chlorofluorocarbon. Examples thereof include a bulk polymerization method, and an emulsion polymerization method in which a vinyl fluoride compound is charged with water in a surfactant and emulsified, and then reacted with tetrafluoroethylene gas for polymerization. In any of the above polymerization methods, the reaction temperature is preferably 30 to 90 ° C., and the reaction pressure is preferably 280 to 1100 kPa.
The melt index MI (g / 10 minutes) measured at 270 ° C., load 2.16 kgf, orifice inner diameter 2.09 mm based on JIS K-7210 of the precursor polymer thus produced is not limited. It is preferably 0.001 or more and 1000 or less, 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 is immersed in a basic reaction liquid and subjected to a hydrolysis treatment at 10 to 90 ° C. for 10 seconds to 100 hours. The basic reaction liquid is not limited, but an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as potassium hydroxide or sodium hydroxide is preferred. The content of the alkali metal or alkaline earth metal hydroxide in the basic reaction liquid is not limited, but is preferably 10 to 30% by mass with respect to the mass of the basic reaction liquid. The basic reaction liquid preferably contains a swellable organic compound such as dimethyl sulfoxide or methyl alcohol. As a content rate of the swellable organic compound in a basic reaction liquid, it is preferable that it is 1-30 mass% with respect to the mass of a basic reaction liquid.
After the hydrolysis treatment as described above, the perfluorocarbon polymer having a proton exchange group is produced by further acid treatment with hydrochloric acid or the like. The proton exchange capacity of the perfluorocarbon polymer having a proton exchange group is not limited, but is preferably 0.50 to 4.00 per gram, more preferably 1.00 to 4.00, and most preferably 1.25 to 2. 50.

Next, a perfluorocarbon polymer having a proton exchange group in a proton solvent is obtained by, for example, putting the perfluorocarbon polymer having a proton exchange group and a proton solvent into an autoclave and performing a heat treatment at 40 to 300 ° C. for 10 minutes to 100 hours. Can be obtained. The solution here includes a state in which the perfluorocarbon polymer is dispersed in a micelle form. The content of the perfluorocarbon polymer in the pre-stage solution B is preferably 0.1 to 50 mass%, more preferably 0.1 to 30 mass%, most preferably 1 with respect to the mass of the pre-stage solution B. -10 mass%.

  The pre-stage solution A and the pre-stage solution B produced as described above are mixed by a known stirring method. Further, if necessary, concentration is performed. In this way, a casting liquid is obtained.

  In the present invention, the polymer electrolyte membrane of the present invention can be obtained by removing the liquid medium constituting the cast liquid at the same time as casting on the support using the above cast liquid. As a casting method in such a manufacturing method, a known spraying technique can be used. Since the proton exchange resin and the polyphenylene ether resin are phase-separated at once by taking a method of rapidly removing the liquid medium, it is possible to produce the polymer electrolyte membrane of the present invention having a finer phase separation state. It is possible and preferable.

The spray method can be broadly divided into a one-fluid spray method and a two-fluid spray method when divided according to the method of atomizing the fluid, and either method can be used.
A typical example of the former is an airless spray method in which the coating material is extruded from a small orifice at an appropriate liquid pressure, and the coating liquid is atomized by the extrusion speed. As the orifice nozzle, an airless cone nozzle, an airless flat nozzle, a cross cut nozzle, a dome nozzle, or the like can be used. Further, centrifugal atomization spraying, ultrasonic spraying, and the like also correspond to the one-fluid spraying method.

  In order to obtain the polymer electrolyte membrane of the present invention in a more preferred form, the cast liquid is siphoned from a cup or pressurized from a tank to supply the cast liquid to a spray gun nozzle, and the compressed gas is discharged from the nozzle. It is desirable to use a two-fluid spray method called air spray that crushes and atomizes the cast liquid. By performing such air spraying, a dense polymer electrolyte membrane without pores can be obtained. In order to obtain the polymer electrolyte membrane of the present invention in the most preferred form, a swirling flow of compressed gas is generated using a specially processed nozzle and air cap, and the cast liquid discharged from the nozzle is crushed and atomized. The polymer electrolyte membrane is formed by forming fine droplets having an average particle size of 0.1 to 100 μm, preferably 1 to 10 μm, and coating the support in a conical shape with a diameter of 1 mm to 100 mm, preferably 10 to 50 mm. It is more desirable to use an air spray method called swirl spray. By performing such a swirl spray, it is possible to obtain a polymer electrolyte membrane having no pores and being dense and having a small film thickness distribution.

Moreover, you may spray by the discharge pattern called the monofilament pattern which performs a bead, dot application | coating, a film-form application partially, and a pulse form. It is also possible to use an aerocoat spray in which the paint is atomized into submicrons and adsorbed and laminated on the substrate by electrostatic force.
Although the support body used for casting is not limited, a general polymer film, a metal foil, a substrate such as alumina, Si, or the like can be suitably used. In the present invention, when casting on a support, the support is preferably heated in advance to 40 to 200 ° C, preferably 60 to 160 ° C. Such a support is removed from the polymer electrolyte membrane as desired when forming a membrane / electrode assembly (described later). Moreover, you may apply | coat to the film which consists of proton exchange resin depending on the case.

The coating film cast as described above may be cast to a target film thickness by one casting, but may be divided into several times and cast to a target film thickness. In addition, as a method for producing a polymer electrolyte laminated film, the above-mentioned casting solution and the pre-stage solution B are prepared separately, and by alternately casting and drying these solutions, a reinforcing layer and an unreinforced layer are alternately provided. A multilayered polymer electrolyte laminated film of the present invention can be produced.
The polymer electrolyte membrane thus obtained may be subjected to heat treatment (annealing) at 40 to 300 ° C., preferably 80 to 200 ° C., if desired. (By heat treatment, the liquid medium can be completely removed, and the structure of the component (a) and the component (b) is stabilized.) Further, in order to fully exhibit the original ion exchange capacity, if desired, The acid treatment may be performed with hydrochloric acid or nitric acid. (If the proton exchange group of the polymer electrolyte membrane is partially substituted with a salt, it can be returned to the proton exchange group by this acid treatment.) Also, a lateral uniaxial tenter or simultaneous biaxial tenter is used. It is also possible to impart stretch orientation.

  As a method for producing a polymer electrolyte laminate film using the polymer electrolyte membrane produced by the above method, a film comprising the polymer electrolyte membrane of the present invention and a proton exchange resin was prepared separately, and these were laminated. Examples of the bonding method include a known press technique such as a hot press, a roll press, and a vacuum press, and a lamination technique. At this time, if necessary, the film composed of the polymer electrolyte membrane of the present invention and a proton exchange resin is bonded on a base material such as a general polymer film, metal foil, alumina, or Si. Also good. Moreover, you may peel the base material used after joining as needed.

(Membrane / electrode assembly)
When the polymer electrolyte membrane or polymer electrolyte laminate membrane of the present invention is used for a solid polymer fuel cell, the membrane in which the polymer electrolyte membrane or polymer electrolyte laminate membrane of the present invention is held tightly between the anode and the cathode / Membrane / electrode assembly (hereinafter often referred to as "MEA"). Here, the anode is composed of an anode catalyst layer and has proton conductivity, and the cathode is composed of a cathode catalyst layer and has proton conductivity. Further, a gas diffusion layer (described later) joined to the outer surface of each of the anode catalyst layer and the cathode catalyst layer is also referred to as MEA.

The anode catalyst layer includes a catalyst that easily oxidizes fuel (for example, hydrogen) to easily generate protons, and the cathode catalyst layer reacts protons and electrons with an oxidizing agent (for example, oxygen or air) to generate water. Includes catalyst. For both the anode and the cathode, platinum or a catalyst in which platinum and ruthenium are alloyed is preferably used as the catalyst, and the catalyst particles are preferably 10 to 1000 angstroms or less. Such catalyst particles are preferably supported on conductive particles having a size of about 0.01 to 10 μm such as furnace black, channel black, acetylene black, carbon black, activated carbon, and graphite. The amount of catalyst particles supported relative to the projected area of the catalyst layer is preferably 0.001 mg / cm ^{2 to} 10 mg / cm ² or less.

Further, the anode catalyst layer and the cathode catalyst layer preferably contain a perfluorocarbon sulfonic acid polymer represented by the above formula (2) or the above formula (3). The supported amount with respect to the projected area of the catalyst layer is preferably 0.001 mg / cm ^{2 to} 10 mg / cm ² or less.
As a method for manufacturing the MEA, for example, the following method can be given. First, a commercially available platinum-supporting carbon (for example, TEC10E40E manufactured by Kuninaka Tanaka Kikai Co., Ltd.) is used as a catalyst in a perfluorocarbon sulfonic acid polymer dissolved in a mixed solution of alcohol and water to form a paste. A certain amount of this is applied to one side of each of the two PTFE sheets and dried to form a catalyst layer. Next, the coated surfaces of each PTFE sheet are faced to each other, the polymer electrolyte membrane or polymer electrolyte laminated film of the present invention is sandwiched therebetween, and is transferred and bonded by hot pressing at 100 to 200 ° C., and then the PTFE sheet is By removing, MEA can be obtained. A person skilled in the art knows how to make MEAs. The method for producing MEA is described in, for example, JOURNAL OF APPLIED ELECTROCHEMISTRY, 22 (1992) p. 1-7.

Moreover, it is preferable that the polymer electrolyte membrane of the present invention as described above is formed only in a portion in contact with the edge of the anode catalyst layer and / or the cathode catalyst constituting the MEA of the present invention. The edge said here may include the periphery 0.1-10 cm.
As the gas diffusion layer, commercially available carbon cloth or carbon paper can be used. Representative examples of the former include carbon cloth E-tek, B-1 manufactured by DE NORA NORTH AMERICA, USA. Representative examples of the latter include CARBEL (registered trademark, Japan Gore-Tex, Japan), Japan. Examples thereof include TGP-H manufactured by Kunito Toray and carbon paper 2050 manufactured by SPCTRACORP. A structure in which the electrode catalyst layer and the gas diffusion layer are integrated is called a “gas diffusion electrode”. MEA can also be obtained by bonding the gas diffusion electrode to the polymer electrolyte membrane or polymer electrolyte laminate film of the present invention. A typical example of a commercially available gas diffusion electrode is a gas diffusion electrode ELAT (registered trademark) manufactured by DE NORA NORTH AMERICA (using carbon cloth as a gas diffusion layer).

(Solid polymer fuel cell)
Basically, when the anode and cathode of the MEA are bonded to each other via an electron conductive material located outside the polymer electrolyte membrane or the polymer electrolyte laminated membrane, an operable polymer electrolyte fuel cell is obtained. be able to. A person skilled in the art knows how to make a polymer electrolyte fuel cell. The polymer electrolyte fuel cell is prepared by, for example, FUEL CELL HANDBOOK (VAN NOSTRAND REINHOLD, AJ APPLEBY et.al, ISBN 0-442-31926-6), Chemical One Point, Fuel Cell (Second Edition). ), Masao Taniguchi, Manabu Senoo, Kyoritsu Shuppan (1992).

As the electron conductive material, a current collector such as a composite material of graphite or resin having a groove for flowing a gas such as fuel or oxidant on its surface, or a metal plate is used. When the MEA does not have a gas diffusion layer, the MEA is incorporated into a single cell casing (for example, PEFC single cell manufactured by Electrochem Inc., USA) with the gas diffusion layer positioned on the outer surface of each anode and cathode of the MEA. Thus, a polymer electrolyte fuel cell can be obtained.
In order to extract a high voltage, the fuel cell is operated as a stack cell in which a plurality of single cells as described above are stacked. In order to produce such a fuel cell as a stack cell, a plurality of MEAs are produced and assembled into a stack cell casing (for example, PEFC stack cell manufactured by US Electrochem Corp.). In such a fuel cell as a stack cell, a current collector called a bipolar plate is used which serves to separate the fuel and oxidant of adjacent cells and to serve as an electrical connector between the adjacent cells.

The fuel cell is operated by supplying hydrogen to one electrode and oxygen or air to the other electrode. The higher the operating temperature of the fuel cell, the higher the catalyst activity. Usually, it is often operated at 50 to 80 ° C., where moisture management is easy, but it can also be operated at 80 to 150 ° C.
In addition, the polymer electrolyte membrane of the present invention is formed in one or more kinds selected from only the anode gas inlet portion, only the anode gas outlet portion, only the cathode gas inlet portion, and only the cathode gas outlet portion of the fuel cell of the present invention. Preferably it is. The inlet portion and the outlet portion referred to herein may include 0.1 to 10 cm around the portion (manifold) into which gas is introduced.

The polymer electrolyte membrane or polymer electrolyte laminated membrane of the present invention can also be used for chloralkali electrolysis, water electrolysis, hydrohalic acid electrolysis, salt electrolysis, oxygen concentrator, humidity sensor, gas sensor and the like. For a method of using the polymer electrolyte membrane for the oxygen concentrator, see, for example, Chemical Engineering, 56 (3), p. 178-180 (1992) and U.S. Pat. No. 4,879,0.
No. 16 can be referred to. For a method of using a polymer electrolyte membrane for a humidity sensor, see, for example, Journal of the Japan Ion Exchange Society, 8 (3), p. 154-165 (1997) and J. Fang et al., Macromolecules, 35, 6070 (2002). For a method of using a polymer electrolyte membrane for a gas sensor, see, for example, Analytical Chemistry, 50 (9), p. 585-594 (2001) and X. Yang, S. Johnson, J. Shi, T. Holesinger, B. Swanson: Sens. Actuators B, 45, 887 (1997).

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not restrict | limited to an Example. Evaluation methods and measurement methods used in the present invention are as follows.
(TEM observation)
The polymer electrolyte membrane is cut into 0.5 mm × 15 mm pieces and placed in a petri dish, 0.1 g of ruthenium (III) chloride n hydrate and 5 ml of sodium hypochlorite solution are added, and the polyphenylene ether resin in the membrane Was stained with Ru. Thereafter, it is embedded in an epoxy resin (for example, Quetol-812 manufactured by Nissin EM, Japan), and in the film thickness direction using a microtome (ULTRACUT (registered trademark) UCT manufactured by LEICA, Germany) (using a diamond knife). It was cut and ultrathin sections having a thickness of 80 to 100 nm were prepared. The ultrathin slice was placed on a copper mesh, and the cross section of the membrane was observed at an acceleration voltage of 125 kV and a magnification of 50000 times using a transmission electron microscope (H7100, manufactured by Hitachi, Ltd. Japan). Observation was performed by randomly selecting one section of the cross section.

(Proton conductivity measurement)
A membrane sample is cut out in a wet state and the thickness T is measured. And it attached to the conductivity measuring cell of 2 terminal type which measures the conductivity of the film length direction of width 1cm and length 5cm. This cell was placed in ion exchange water at 80 ° C., and the resistance value R of the real component at a frequency of 10 kHz was measured by an alternating current impedance method, and proton conductivity σ was 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)

(Tensile creep property)
Tensile creep characteristics were examined using a three-creep creep tester (CP3-P-20 manufactured by Orientec Co., Ltd.). First, a membrane sample is cut out in a wet state, and the thickness T is measured. Then, a film having a width of 1 cm and a length of 5 cm was mounted on the chuck with a chuck interval of 2 cm. The test was performed in a constant temperature and humidity chamber and maintained at 80 ° C. and 95% RH. The test load was 20 kg / cm ² , and the ratio (%) to the initial value (2 cm) of the length extended at 40 hours from the start of the test was calculated as the creep amount.

(Change in wet and dry dimensions)
The swelling ratio when wet (hereinafter referred to as X) is the dimension in the vertical direction when the membrane sample is left in water at 80 ° C. for 1 hour, compared to the vertical dimension when the membrane sample is left at 25 ° C. and 20% RH for 8 hours. It was calculated as a ratio. On the other hand, the shrinkage ratio (hereinafter referred to as X ′) at the time of re-drying is that after standing in water at 80 ° C. for 1 hour with respect to the vertical dimension when the membrane sample is left at 25 ° C. and 20% RH for 8 hours. It was determined as the ratio of the dimensions in the longitudinal direction when it was left to dry at 25 ° C. and 20% RH for 2 hours. Further, the swelling ratio in the transverse direction perpendicular to the longitudinal direction was measured in the same manner as described above, and the ratio Y of the swelling ratio to X was calculated to evaluate the isotropy of the wet and dry dimensional change.

(OCV acceleration test)
In order to accelerate evaluation of the oxidation resistance of the polymer electrolyte membrane under high temperature and low humidification conditions, the following OCV accelerated test was conducted. Here, “OCV” means an open circuit voltage. This OCV accelerated test is an accelerated test intended to promote chemical deterioration of the polymer electrolyte membrane by maintaining the OCV state. (For details on the OCV accelerated test, refer to the 2002 Japan New Energy and Industrial Technology Development Organization commissioned research “Research and development of polymer electrolyte fuel cells (related to establishment of membrane acceleration evaluation technology, etc.)” Asahi Kasei Corporation ) It is described in the result report p.53-57.)

First, the anode-side gas diffusion electrode and the cathode-side gas diffusion electrode were faced to each other, and a polymer electrolyte membrane was sandwiched between them and incorporated in an evaluation cell. As the gas diffusion electrode, a gas diffusion electrode ELAT (registered trademark) manufactured by DE NORA NORTH AMERICA (Pt loading amount of 0.4 mg / cm ² , the same shall apply hereinafter) to a 5% by mass perfluorosulfonic acid polymer solution SS-910 (Asahi Kasei Co., Ltd., equivalent mass (EW): 910, solvent composition (mass ratio): ethanol / water = 50/50) applied, dried and fixed at 140 ° C. in an air atmosphere did. The amount of polymer supported was 0.8 mg / cm ² .
After this evaluation cell was set in an evaluation apparatus (manufactured by Chino Co., Ltd., Japan) and heated, hydrogen gas was supplied to the anode side and air gas was supplied to the cathode side at 200 cc / min to maintain the OCV state. A water bubbling method was used for gas humidification, and both hydrogen gas and air gas were humidified and supplied to the cell. The test conditions were a cell temperature of 100 ° C., a gas humidification temperature of 50 ° C., and no pressure (atmospheric pressure) on both the anode side and the cathode side.

In order to investigate whether or not pinholes were generated in the polymer electrolyte membrane every 10 hours from the start of the above test, hydrogen gas permeation was performed using a flow type gas permeability measuring device GTR-100FA manufactured by GTR Tech, Japan. The rate was measured. With the anode side of the evaluation cell held at 0.15 MPa with hydrogen gas, argon gas was flowed at 10 cc / min as the carrier gas to the cathode side, and hydrogen that had permeated from the anode side to the cathode side due to cross leak in the evaluation cell. It introduce | transduces into gas chromatograph G2800 with gas, and quantifies the permeation | transmission amount of hydrogen gas. Hydrogen gas permeation amount X (cc), correction coefficient B (= 1.100), polymer electrolyte membrane thickness T (cm), hydrogen partial pressure P (Pa), hydrogen permeation area of polymer electrolyte membrane A (cm ² ) and hydrogen gas permeability L (cc × cm / cm ² / sec / Pa) when the measurement time is D (sec) is calculated from the following equation.
L = (X × B × T) / (P × A × D)
When the hydrogen gas permeability reached 10 times the value before the OCV test, it was determined as a cross leak and the test was terminated.

(Fuel cell evaluation)
In order to examine the initial battery characteristics (hereinafter referred to as initial characteristics) of the membrane / electrode assembly produced below, the following fuel cell evaluation was performed.
To 1.00 g of Pt-supported carbon (TEC10E40E, Pt 36.4 mass%, manufactured by Nihon Kuninaka Precious Metal Co., Ltd.), 7.33 g of the above-mentioned pre-stage solution was added and mixed well with a homogenizer to prepare an electrode catalyst composition. Obtained. This electrode catalyst composition was applied on a PTFE sheet by a screen printing method. After coating, the film was dried at room temperature for 1 hour and in air at 160 ° C. for 1 hour. Thus, an electrode catalyst layer having a 3.5 cm square and a thickness of 10 μm was obtained. Of these electrode catalyst layers, those having a Pt loading of 0.15 mg / cm ² were used as anode catalyst layers, and those having a Pt loading of 0.30 mg / cm ² were used as cathode catalyst layers.
An anode catalyst layer, a cathode catalyst layer, and a polymer electrolyte membrane to be prepared below are faced with the center portions aligned, sandwiched between them, and hot-pressed at 180 ° C. and a surface pressure of 0.1 MPa. The layer was transferred and joined to a polymer electrolyte membrane to prepare an MEA.

  Next, the anode side gas diffusion layer and the cathode side gas diffusion layer faced each other, and the MEA was sandwiched between them and incorporated in the evaluation cell. As the gas diffusion layer, carbon cloth (ELAT (registered trademark) B-1 manufactured by DE NORA NORTH AMERICA, USA) was set and incorporated in the evaluation cell. This evaluation cell is set in an evaluation apparatus (manufactured by Chino Co., Ltd., Japan) and heated to 80 ° C., then hydrogen gas is supplied to the anode side at 300 cc / min and air gas is supplied to the cathode side at 800 cc / min. The anode and cathode were pressurized at 0.15 MPa (absolute pressure). A water bubbling system was used for gas humidification, and the initial characteristics were examined by measuring a current-voltage curve in a state where the gas was humidified at 85 ° C. and the air gas was humidified at 75 ° C. and supplied to the cell.

(Durability acceleration evaluation)
After examining the initial characteristics as described above, the durability under high-temperature and low-humidification conditions was acceleratedly evaluated as follows.
First, the cell temperature was 100 ° C., and gas humidification was performed at 60 ° C. saturated water vapor pressure and no pressure (atmospheric pressure) on both the anode side and the cathode side. Then, hydrogen gas was supplied to the anode side and air gas was supplied to the cathode side at 100 cc / min to maintain the OCV state. Here, “OCV” means an open circuit voltage.

In order to investigate whether or not pinholes were generated in the polymer electrolyte membrane every 10 hours from the start of the above test, hydrogen gas permeation was performed using a flow type gas permeability measuring device GTR-100FA manufactured by GTR Tech, Japan. The rate was measured. With the anode side of the evaluation cell held at 0.15 MPa with hydrogen gas, argon gas was flowed at 10 cc / min as the carrier gas to the cathode side, and hydrogen that had permeated from the anode side to the cathode side due to cross leak in the evaluation cell. It introduce | transduces into gas chromatograph G2800 with gas, and quantifies the permeation | transmission amount of hydrogen gas. Hydrogen gas permeation amount X (cc), correction coefficient B (= 1.100), polymer electrolyte membrane thickness T (cm), hydrogen partial pressure P (Pa), hydrogen permeation area of polymer electrolyte membrane Is A (cm ² ), and hydrogen gas permeability L (cc · cm ⁻¹ · sec ⁻¹ · Pa ⁻¹ ) when the measurement time is D (sec) is calculated from the following equation.
L = (X × B × T) / (P × A × D)
The test was terminated when the hydrogen gas permeability reached 10 times the value before the test.

[Example 1]
As a proton exchange resin, a perfluorosulfonic acid polymer represented by [CF ₂ CF ₂ ] _0.812- [CF ₂ -CF (—O— (CF ₂ ) ₂ —SO ₃ H)] _0.188 (hereinafter “PFS”) Used). Further, as polyphenylene ether resin, poly (2,6-dimethyl-1,4-phenylene ether) represented by the following chemical formula (4) (manufactured by Asahi Kasei Chemicals Co., Ltd., hereinafter referred to as PPE) is used, and PFS / PPE = 87/13 (mass ratio), a proton exchange capacity of 1.22 meq / g, and a film thickness of 20 μm were produced as follows.

（式中、ｎは１以上の整数）

(Where n is an integer of 1 or more)

First, as a PFS precursor polymer, a perfluorocarbon polymer (MI: 3.0) of tetrafluoroethylene and CF ₂ ═CFO (CF ₂ ) ₂ —SO ₂ F was produced. The precursor polymer was subjected to a hydrolysis treatment by bringing it into contact with an aqueous solution in which potassium hydroxide (15% by mass) and dimethyl sulfoxide (30% by mass) were dissolved at 60 ° C. for 4 hours. Then, it was immersed in 60 degreeC water for 4 hours. Next, it was immersed in a 2N aqueous hydrochloric acid solution at 60 ° C. for 3 hours, then washed with ion-exchanged water and dried to obtain PFS having an ion-exchange capacity of 1.41 meq / g.

This PFS was placed in an autoclave together with an aqueous ethanol solution (water: ethanol = 50.0: 50.0 (mass ratio)), sealed, heated to 180 ° C. and held for 5 hours. Thereafter, the autoclave was naturally cooled to produce a pre-stage solution B having a composition of PFS: water: ethanol = 5.0: 47.5: 47.5 (mass ratio).
On the other hand, PPE having an intrinsic viscosity of 0.52 (dl / g) measured at 30 ° C. with a 0.5 g / dl chloroform solution was used. This PPE was put in toluene and stirred at room temperature to prepare a pre-stage solution A having a composition of PPE / toluene = 5.7 / 94.3 (mass ratio).

Next, 100 g of the pre-stage solution B was added to 13.1 g of the pre-stage solution A and stirred to obtain a casting solution. The concentrations of PFS and PPE in this casting solution were 4.4% by mass and 0.7% by mass, respectively.
30 g of this casting solution was charged into a spray gun (W-100 manufactured by Anest Iwata Co., Ltd.) and repeatedly directed at a metal plate of SUS304 preheated to 60 ° C. at an air pressure of 7 kg / cm ² from about 15 cm away. Sprayed. Then, the metal plate was placed in an oven at 160 ° C. for 30 minutes for heat treatment, and then wetted with water and peeled off from the metal plate to obtain a polymer electrolyte membrane of the present invention having a thickness of 20 μm. This film was pale yellowish white. As a result of TEM observation of the cross section in the film thickness direction, as shown in FIG. 1, PFS (transparent portion) and PPE (black portion) are phase-separated, PPE has a minor axis of 0.01 to 4 μm, and an aspect ratio is 1 to 400 were confirmed to be uniformly dispersed in a needle shape and oriented perpendicular to the film thickness direction.

The proton conductivity of this membrane was 0.21 S / cm, and the creep amount was 15%. Further, when the wet and dry dimensional change was measured, the swelling and shrinkage of the film was small with X = 110% and X ′ = 98%. The swelling and shrinkage change of the film was small with Y = 0.9, and the dimensional change was isotropic. It was the target.
When this film was subjected to an OCV acceleration test, no cross leak occurred even when a 100 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 2]
Except that 34.0 g of the pre-stage solution A was added with 100 g of the pre-stage solution B and stirred to obtain a casting liquid (PFS and PPE concentrations of 3.7 mass% and 1.4 mass%, respectively) A polymer electrolyte membrane having a PFS / PPE = 72/28 (mass ratio), a proton exchange capacity of 0.99 meq / g, and a film thickness of 20 μm was produced in the same manner as in Example 1. This film was pale yellowish white. When a TEM observation of the cross section in the film thickness direction was performed, as shown in FIG. 2, PFS (transparent portion) and PPE (black portion) were phase-separated, and PPE had a minor axis of 0.01 to 0.5 μm and an aspect ratio. A fine structure was observed in which the ratio was 1 to 10000 and the fibers were uniformly dispersed in a fiber shape and oriented perpendicular to the film thickness direction, and the dispersed PPEs were connected to each other. At this time, the size of the minute nodule portion was 0.1 to 2 μm.

The proton conductivity of this membrane was 0.19 S / cm, and the creep amount was 6%. In addition, when the wet and dry dimensional change was measured, the swelling / shrinkage change of the film was small as X = 102% and X ′ = 99%, the swelling / shrinkage change of the film was small as Y = 0.95, and the dimensional change was equal Was. When this film was subjected to an OCV acceleration test, no cross leak occurred even when a 100 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 3]
A polymer electrolyte membrane of the present invention having a thickness of 10 μm and PFS / PPE = 80/20 (mass ratio) was produced as follows.
4.2 g of isopropyl alcohol was added to 100.0 g of the same pre-stage solution B as in Example 1, and PFS: water: ethanol: isopropyl alcohol = 4.8: 45.6: 45.6: 4.0 ( A pre-stage solution B1 having a composition of (mass ratio) was prepared.
On the other hand, 42.5 g of toluene was added to 50.0 g of the same pre-stage solution A as in Example 1 to prepare a pre-stage solution A1 having a composition of PPE: toluene = 2.0: 98.0 (mass ratio). did.

Next, 62.5 g of the pre-stage solution A1 was added to and mixed with 100.0 g of the pre-stage solution B1 to obtain a milky emulsion casting liquid C1.
The cast liquid C1 was charged into a swirl spray gun (manufactured by Nordson Co., Ltd.) and directed to a metal plate of SUS304 heated to 50 ° C. From a distance of 5 cm, the atomizing air pressure was 0.4 MPa and the liquid pressure was 0.04 MPa. Cast liquid C1 was sprayed. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed twice.

  The metal plate was placed in an oven at 160 ° C. for 30 minutes and then subjected to heat treatment, and then immersed in ion-exchanged water to peel off the film from the metal plate. The film thickness was 10 μm and PFS / PPE = 80/20 (mass ratio). A polymer electrolyte membrane of the present invention was obtained. This film was transparent but slightly white. As a result of TEM observation of the cross section of the film, as shown in FIG. 3, PFS (white part) and PPE (gray part) were phase-separated from each other, and the PPE that was phase-separated in the form of filaments was oriented perpendicular to the film thickness direction. It was confirmed that The short diameter of the filamentous PPE was 0.1 to 2 μm, and the ratio of the short diameter to the long diameter was 10 to 1000, which was uniformly dispersed in the film. In addition, PPE having a ratio of the minor axis to the major axis of 1 to 2 is also observed, which is considered to be a cross section obtained by cutting the filamentous PPE orthogonal to the membrane cross section.

  The proton conductivity of this membrane was 0.21 S / cm, and the creep amount was 6%. Further, when the wet and dry dimensional change measurement was performed, the changes in swelling and shrinkage of the film were extremely small and X was 100.5%, X ′ = 100%, and Y = 1.01, and the dimensional change was isotropic. When this film was subjected to an OCV acceleration test, no cross leak occurred even when a 100 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 4]
An example of a polymer electrolyte laminated film obtained by press-bonding the same polymer electrolyte membrane as in Example 2 and the following two proton exchange resin membranes is shown below.
The pre-stage solution B used in Example 1 was poured into a stainless steel petri dish having a diameter of 9.1 cm, put in an oven, heated to 200 ° C., and heat-treated for 2 hours to remove the solvent. Then, it took out from oven, poured ion-exchange water into the cooled stainless steel petri dish, the peeled film was dried with the filter paper, and the proton exchange resin membrane with a film thickness of 15 micrometers was obtained. Two sheets of this proton exchange resin membrane were prepared.

Between the two proton exchange resin membranes thus obtained, the same polymer electrolyte membrane as in Example 2 was put, and these membranes were made of Kapton film (300H, manufactured by DuPont Co., Ltd., film thickness 75 μm). I caught it. This was set in a compression molding machine (VSF-10, manufactured by Shindo Metal Industry Co., Ltd.), vacuum deaeration was performed until the atmosphere became 1.6 kPa, and after raising the temperature to 190 ° C., 1.5 MPa Pressed for 10 minutes. After the press, the pressure was released and the temperature was lowered to 50 ° C., then the atmosphere was returned to atmospheric pressure, and a sample was taken out.
Furthermore, the polymer electrolyte laminated film of this invention was obtained by immersing a sample in ion-exchange water, peeling a film | membrane from a Kapton film, and making it dry.

  The laminated film had a proton conductivity of 0.22 S / cm and a creep amount of 6%. Further, when the dry / wet dimensional change was measured, the change in swelling and shrinkage of the film was extremely small, with X = 102.0%, X ′ = 100%, and Y = 1.1, and the dimensional change was isotropic. When this film was subjected to an OCV acceleration test, no cross leak occurred even when a 100 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 5]
Two polymer electrolyte membranes obtained by spraying the same casting solution as in Example 2 on a 10 μm-thick proton exchange resin membrane produced by the same method as in Example 4, and the thickness produced by the same method as in Example 4. An example of a polymer electrolyte laminate film obtained by press-bonding one 10 μm proton exchange resin film is shown below.
The casting liquid used in Example 2 was charged into the same swirl spray gun as used in Example 3, and the proton exchange resin film having a thickness of 10 μm produced by the same method as in Example 4 was fixed to a metal plate at 50 ° C. The cast liquid was sprayed at an atomizing air pressure of 0.4 MPa and a hydraulic pressure of 0.04 MPa from a location 5 cm away from the heating. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed twice.

The metal plate was placed in an oven at 160 ° C. for 30 minutes for heat treatment, and then the membrane was peeled off from the metal plate to obtain a polymer electrolyte membrane. Two such polymer electrolyte membranes were prepared.
Two layers of the polymer electrolyte membrane thus obtained with the casting liquid spraying surface facing up are stacked, and a proton exchange resin membrane with a thickness of 10 μm is further placed thereon, and these membranes are placed on a Kapton film (DuPont Co., Ltd.). 300H, film thickness 75 μm). This was set in the same compression molding machine as used in Example 4, and the polymer electrolyte laminate film of the present invention was obtained in the same procedure as in Example 4.

  The laminated film had a proton conductivity of 0.22 S / cm and a creep amount of 6%. In addition, when the wet and dry dimensional change measurement was performed, the swelling and shrinkage change of the film was extremely small with X = 102.5%, X ′ = 100.5% and Y = 0.95, and the dimensional change was isotropic. It was. When this film was subjected to an OCV acceleration test, no cross leak occurred even when a 100 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 6]
A polymer electrolyte membrane of the present invention having fine film thickness of 10 μm and PFS / PPE / PPS = 80/20/7 (mass ratio) containing fine particles of polyphenylene sulfide resin (hereinafter referred to as PPS) was produced as follows. .
PR11-10 manufactured by Chevron Phillips Chemical Co., Ltd. was used as the PPS resin, and this was finely pulverized with a jet mill to obtain fine particles having an average particle diameter (50% volume basis) of 7 μm. The PPS fine particles were added to and mixed with the same casting liquid C1 as that prepared in Example 3 to obtain a white turbid casting liquid C2.

This casting liquid C2 was charged into a swirl spray gun, and a polymer electrolyte membrane was prepared by the same method as in Example 3. The film thickness was 10 μm and PFS / PPE / PPS = 80/20/7 (mass ratio). A molecular electrolyte membrane was obtained.
The proton conductivity of this membrane was 0.20 S / cm, and the creep amount was 6%. Further, when the wet and dry dimensional change measurement was performed, the swelling / shrinkage change of the film was extremely small and X = 100.5%, X ′ = 99% and Y = 1.00, and the dimensional change was isotropic. When this film was subjected to an OCV accelerated test, no cross leak occurred even when a 200 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 7]
The polymer electrolyte laminate film of the present invention in which 16 layers of reinforcing layers made of PFS / PPE / PPS = 80/20/7 (mass ratio) and non-reinforced layers made only of PFS were alternately laminated was produced as follows. .
Cast liquid C2 was charged into the same swirl spray gun used in Example 3, and directed to a metal plate of SUS304 heated to 50 ° C. From a distance of 5 cm, the atomizing air pressure was 0.4 MPa and the liquid pressure was 0.04 MPa. Cast liquid C2 was sprayed. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed once.

Subsequently, the pre-stage solution B was charged into another swirl spray gun and sprayed toward the metal plate in the same manner as described above. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed once.
The above-described spraying of the casting liquid C2 and the spraying of the previous-stage solution B were repeated 4 times each. The metal plate was placed in an oven at 160 ° C. for 30 minutes and then heat-treated, and then immersed in ion-exchanged water to peel off the film from the metal plate. The film thickness was 25 μm, and 8 layers of reinforcing layers and non-reinforcing layers were alternately arranged. A laminated film was obtained.

Two films as described above were prepared, and two sheets were stacked so that the non-reinforcing layer side faced upward, and these films were sandwiched between Kapton films. This was set in the same compression molding machine as used in Example 4, and the polymer electrolyte laminate film of the present invention was obtained in the same procedure as in Example 4. In this laminated film, 16 layers of reinforcing layers made of PFS / PPE / PPS = 80/20/7 (mass ratio) and unreinforced layers made only of PFS were laminated alternately.
The proton conductivity of this membrane was 0.20 S / cm, and the creep amount was 6%. Further, when the wet / dry dimensional change measurement was performed, the changes in swelling and shrinkage of the film were extremely small and X = 101.5%, X ′ = 99%, and Y = 1.03, and the dimensional change was isotropic. When this film was subjected to an OCV accelerated test, no cross leak occurred even when a 200 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 8]
The polymer electrolyte laminate film of the present invention in which 16 layers of reinforcing layers made of PFS / PPE / PPS = 80/20/7 (mass ratio) and non-reinforced layers made only of PFS were alternately laminated was produced as follows. .
Cast liquid C2 was charged into the same swirl spray gun used in Example 3, and directed to a metal plate of SUS304 heated to 50 ° C. From a distance of 5 cm, the atomizing air pressure was 0.4 MPa and the liquid pressure was 0.04 MPa. Cast liquid C2 was sprayed. At this time, a swirl spray gun is attached to an X, Y, Z 3-axis robot controlled by an AC servo motor, and the X-axis speed is 150 mm / sec.
Driven with a Y-axis pitch of 2.5 mm. This operation was performed once.

Subsequently, the pre-stage solution B was charged into another swirl spray gun and sprayed toward the metal plate in the same manner as described above. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed once.
The above-mentioned spraying of the casting liquid C2 and the spraying of the previous stage solution B were repeated 8 times each. The metal plate was placed in an oven at 160 ° C. for 30 minutes and heat-treated, and then immersed in ion-exchanged water to peel off the film from the metal plate. The thickness was 50 μm, and 16 layers of reinforcing layers and non-reinforcing layers were alternately formed. A laminated polymer electrolyte laminate film of the present invention was obtained. In this laminated film, 16 layers of reinforcing layers made of PFS / PPE / PPS = 80/20/7 (mass ratio) and unreinforced layers made only of PFS were laminated alternately.

  The proton conductivity of this membrane was 0.20 S / cm, and the creep amount was 6%. In addition, when the wet / dry dimensional change measurement was performed, the swelling and shrinkage change of the film was extremely small as X = 101.3%, X ′ = 99.5% and Y = 1.02, and the dimensional change was isotropic. It was. When this film was subjected to an OCV accelerated test, no cross leak occurred even when a 200 hr test was performed. As described above, a polymer electrolyte membrane excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability was obtained while maintaining proton conductivity.

[Example 9]
An example of the membrane / electrode assembly formed by the polymer electrolyte membrane of the present invention having PFS / PPE = 80/20 (mass ratio) only at the portion in contact with the catalyst layer edge is shown below.
First, a 50 μm Teflon (registered trademark) tape was affixed to a SUS304 metal plate in a 4 cm square, and then cut out from a 4 cm square center in a 3 cm square and peeled off. The metal plate was heated to 50 ° C., and the pre-stage solution B was charged into the same swirl spray gun used in Example 3, and the atomizing air pressure was 0.4 MPa from the position 5 cm away from the metal plate. The pre-stage solution B was sprayed at a pressure of 0.04 MPa. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed 10 times.

  Next, the Teflon (registered trademark) tape was peeled off, heated again to 50 ° C., the casting liquid C1 was charged into the same swirl spray gun used in Example 3, and the Teflon (registered trademark) tape of the metal plate was removed. Cast liquid C1 was sprayed at an atomizing air pressure of 0.4 MPa and a hydraulic pressure of 0.04 MPa from a distance of 5 cm toward the part. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor, and the Teflon (registered trademark) tape was peeled off and driven at a speed of 150 mm / sec. This operation was performed 10 times.

Thereafter, the metal plate was placed in an oven at 160 ° C. for 30 minutes for heat treatment, immersed in ion exchange water and peeled off from the metal plate to obtain the polymer electrolyte membrane of the present invention.
MEA was produced using this polymer electrolyte membrane, and battery evaluation was performed. The current density at a voltage of 0.6 V was 1.00 A / cm ² and the initial characteristics were good. In the accelerated durability evaluation, durability of 200 hours or more was shown. From this result, it was found that the membrane / electrode assembly formed only at the portion where the polymer electrolyte membrane of the present invention was in contact with the catalyst layer edge provided good initial characteristics and high durability.

[Example 10]
Examples of the membrane / electrode assembly formed by the polymer electrolyte membrane of the present invention having PFS / PPE = 80/20 (mass ratio) only at the portions in contact with the gas inlet portion and the gas outlet portion will be described below.
First, a 50 μm Teflon (registered trademark) tape was affixed to a SUS304 metal plate in a 5 cm square, and then cut out from the center of the 5 cm square at a 4 cm square, and the center portion was peeled off. The metal plate was heated to 50 ° C., and the pre-stage solution B was charged into the same swirl spray gun used in Example 3, and the atomizing air pressure was 0.4 MPa from the position 5 cm away from the metal plate. The pre-stage solution B was sprayed at a pressure of 0.04 MPa. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor and driven at an X-axis speed of 150 mm / sec and a Y-axis pitch of 2.5 mm. This operation was performed 10 times.

Next, the Teflon (registered trademark) tape was peeled off, heated again to 50 ° C., the casting liquid C1 was charged into the same swirl spray gun used in Example 3, and the Teflon (registered trademark) tape of the metal plate was removed. Cast liquid C1 was sprayed at an atomizing air pressure of 0.4 MPa and a hydraulic pressure of 0.04 MPa from a distance of 5 cm toward the part. At this time, a swirl spray gun was attached to a three-axis robot of X, Y, and Z controlled by an AC servo motor, and the Teflon (registered trademark) tape was peeled off and driven at a speed of 150 mm / sec. This operation was performed 10 times.
Thereafter, the metal plate was placed in an oven at 160 ° C. for 30 minutes for heat treatment, immersed in ion exchange water and peeled off from the metal plate to obtain the polymer electrolyte membrane of the present invention.
MEA was produced using this polymer electrolyte membrane, and battery evaluation was performed. The current density at a voltage of 0.6 V was 1.00 A / cm ² and the initial characteristics were good. In the accelerated durability evaluation, durability of 200 hours or more was shown. From this result, it was found that the membrane / electrode assembly formed by only the portions where the polymer electrolyte membrane of the present invention is in contact with the gas inlet portion and the gas outlet portion can obtain good initial characteristics and high durability.

[Comparative Example 1]
The pre-stage solution B used in Example 1 was poured into a stainless steel petri dish having a diameter of 9.1 cm, put in an oven, heated to 200 ° C., and heat-treated for 2 hours to remove the solvent. Then, it took out from oven, ion-exchange water was poured into the cooled stainless steel petri dish, the peeled film was dried with the filter paper, and the proton exchange resin film | membrane with a film thickness of 50 micrometers was obtained.
The proton conductivity of this membrane was 0.25 S / cm, and the creep amount was 120%. Further, when the wet and dry dimensional change measurement was performed, the swelling shrinkage change of the film was large as X = 125.0% and X ′ = 99%. When this film was subjected to an OCV accelerated test, a cross leak occurred after 30 hours.
As described above, although the proton conductivity is high, the chemical stability, mechanical strength, heat resistance, and dry / wet dimensional stability are insufficient, and the durability is poor.

[Comparative Example 2]
Using the same proton exchange resin membrane as that produced in Comparative Example 1, an MEA was produced and battery evaluation was performed. The current density at a voltage of 0.6 V was 1.00 A / cm ² and the initial characteristics were good. However, in the accelerated durability evaluation, a cross leak occurred at 100 hr, and the test was terminated. Thus, the durability was insufficient.

  The polymer electrolyte membrane of the present invention is excellent in chemical stability, mechanical strength, heat resistance, and wet / dry dimensional stability, and has high durability even when used at high temperatures. The polymer electrolyte fuel cell using the polymer electrolyte membrane of the present invention can be operated for a long time under high-temperature and low-humidity conditions (operating temperature near 100 ° C., 60 ° C. humidification (corresponding to humidity 20% RH)). Because there is no tearing of the polymer electrolyte membrane (such as pinholes), cross-leakage (mixing of fuel and oxidant due to membrane breakage) does not occur, and it is stable for a long time even under severe conditions Can be used.

1 is a cross-sectional view of a polymer electrolyte membrane of Example 1 in which acicular polyphenylene ether resin is oriented perpendicular to the film thickness direction. The film sectional drawing of the polymer electrolyte membrane of Example 2 which has the structure where the fibrous polyphenylene ether resin orientated perpendicularly | vertically to the film thickness direction, and was mutually connected through the micro nodule part. The film cross section of the polymer electrolyte membrane of Example 3 with which the thread-like polyphenylene ether resin is orientated perpendicularly to the film thickness direction.

Claims (14)

  (A) a polymer electrolyte membrane having at least 30.00 to 99.99% by mass of a proton exchange resin, and (b) 0.01 to 70.00% by mass of a polyphenylene ether resin, The polyphenylene ether resin is phase-separated from each other, and the polyphenylene ether resin dispersed in one or more forms selected from thread form, fiber form, and needle form is oriented perpendicular to the film thickness direction. A polymer electrolyte membrane.   2. The polymer electrolyte membrane according to claim 1, wherein the polyphenylene ether resin is randomly oriented in a plane perpendicular to the film thickness direction.   The polyphenylene ether resin dispersed in one or more forms selected from a thread form, a fiber form, and a needle form has a minor axis of 0.01 to 100 μm and a major axis / minor axis ratio of 1 to 10,000. The polymer electrolyte membrane according to claim 1 or 2.   The polyphenylene ether resin dispersed in one or more forms selected from a thread form, a fiber form, and a needle form has a minute nodule part and has a structure connected to each other. The polymer electrolyte membrane according to any one of the above.   The polymer electrolyte membrane according to any one of claims 1 to 4, wherein the size of the minute nodule portion is 0.01 to 10 µm.   The polymer electrolyte membrane according to any one of claims 1 to 5, wherein the proton exchange resin is a fluorine-based polymer electrolyte.   When the direction of the film plane is the X-axis and the direction perpendicular to the X-axis is the Y-axis, the film sample is 80% of the dimension when left for 8 hours at 25 ° C. and 20% RH in the X-axis and Y-axis directions. The swelling ratio when wet, which is the ratio of dimensions when left in water at 1 ° C. for 1 hour, is 100 to 105%, and the ratio of the swelling ratio of the Y axis to the swelling ratio in the X axis direction is 0.5 to 1 The polymer electrolyte membrane according to any one of claims 1 to 6, wherein the polymer electrolyte membrane has an isotropic wet-wet dimensional stability. A polymer electrolyte laminate film comprising a laminate of two or more films having a proton exchange resin, wherein at least one film of the film is the polymer electrolyte membrane according to any one of claims 1 to 7. A polymer electrolyte laminate film characterized by comprising: A method for producing a polymer electrolyte membrane, comprising:
( A ) 30.00-99.99 mass% of proton exchange resin (component (a)) with respect to the total mass of component (a) and component (b),
( B ) Polyphenylene ether resin (component (b)) is 0.01-70.00 mass% with respect to the total mass of component (a) and component (b),
A polymer electrolyte comprising: forming a polymer electrolyte membrane according to any one of claims 1 to 7 by mixing with a liquid medium to form a cast solution, and spraying the cast solution on a support. A method for producing a membrane.   The cast liquid is supplied to a nozzle of a spray gun, a swirling flow of compressed gas is generated, the cast liquid discharged from the nozzle is crushed and atomized, and sprayed in a conical shape toward the support surface to form a polymer electrolyte. The method for producing a polymer electrolyte membrane according to claim 9, wherein the membrane is formed.   9. A membrane / electrode assembly in which the polymer electrolyte membrane or polymer electrolyte laminated membrane according to claim 1 is held in close contact between an anode and a cathode, wherein the anode is an anode catalyst layer. The membrane / electrode assembly is characterized in that it comprises proton conductivity, the cathode comprises a cathode catalyst layer, and has proton conductivity. The polymer electrolyte membrane or polymer electrolyte membrane or polymer electrolyte membrane that is held in close contact between the anode catalyst layer and the cathode catalyst layer, or a polymer electrolyte membrane according to any one of claims 1 to 8 12. The membrane / electrode assembly according to claim 11, wherein the electrolyte laminated film is formed only at a portion in contact with the edge of the anode catalyst layer and / or the cathode catalyst layer. 13. The membrane / electrode assembly according to claim 11 or 12, wherein the anode and the cathode are coupled to each other via a load and an electron conductive material located outside the polymer electrolyte membrane or the polymer electrolyte laminated membrane. A polymer electrolyte fuel cell characterized by comprising: The polymer electrolyte membrane or polymer electrolyte membrane or polymer electrolyte membrane that is held in close contact between the anode catalyst layer and the cathode catalyst layer, or a polymer electrolyte membrane according to any one of claims 1 to 8 The electrolyte laminated film is formed only in at least one inlet portion and / or outlet portion selected from an anode gas inlet portion, an anode gas outlet portion, a cathode gas inlet portion, and an outlet portion. The solid polymer fuel cell as described.

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