JP4217889B2 - Proton conducting fluoropolyether composition for fuel cell electrolyte membrane - Google Patents

Description

The present invention relates to a proton conductive fluoropolyether composition for a fuel cell electrolyte membrane excellent in adhesion, heat resistance and oxidation resistance, a proton conductive fluoropolyether membrane, a method for forming the membrane, and the composition The present invention relates to an electrolyte membrane / electrode assembly for a fuel cell and a fuel cell.

More specifically, as an electrolyte membrane of an electrolyte membrane / electrode assembly in a polymer electrolyte fuel cell using hydrogen or methanol as a fuel, oxidation deterioration due to hydrogen peroxide is suppressed, and methanol used as a fuel even during long-term use is suppressed. Proton-conducting fluoropolyether composition for fuel cell electrolyte membrane , which is effective as a thermosetting material with less permeation and excellent adhesion to the solid catalyst of the electrode layer, and protons obtained from the composition The present invention relates to a conductive fluoropolyether membrane, an electrolyte membrane / electrode assembly for a fuel cell using the same, and a fuel cell.

  In recent years, a scheme to control the total emission of carbon dioxide has been sought at the national level as a measure against global warming. Above all, automobiles use the combustion of petroleum fuel gasoline as energy, and if this is replaced with a fuel cell that emits less carbon dioxide throughout the system, a significant reduction in carbon dioxide can be expected. Research and development of fuel cells are actively conducted including automobile manufacturers. On the other hand, with the spread and high performance of portable electronic devices, new fuel cells are also expected as portable power sources that realize long-time operation of portable electronic devices. In general, fuel cells are classified according to their operating temperature and the type of electrolyte. A fuel cell expected for use in automobiles and portable fuel cells has an operating temperature of 300 ° C. or lower and is called a low temperature type. Depending on the type of electrolyte, it is classified as a solid polymer type (PEFC). This solid polymer type is characterized by small size and high output. Since this PEFC type has excellent advantages in principle, research for practical use has been actively conducted since the latter half of 1980s. Regarding solid electrolyte membranes, Nafion membranes (sulfonated perfluoroalkyl ethers) manufactured by DuPont are attracting attention because of their excellent oxidation degradation resistance and high proton conductivity. In the electrolyte membrane / electrode assembly, a patent of Los Alamos Laboratories filed in 1991 (see Patent Document 1: US Pat. No. 5,234,777) is a paste prepared with a solution containing a carbon-supported platinum catalyst and an electrolyte. In addition, a technique is described in which a Nafion film is sandwiched after printing on carbon paper to be an electrode, and hot utilization is performed to significantly increase the utilization efficiency of platinum as a catalyst.

  However, since the Nafion membrane does not have a cross-linked structure, the required thickness of the solid electrolyte membrane is as thin as 100 μm or less, and does not have thermosetting properties, the catalyst layer and the Nafion membrane can be separated depending on hot press conditions. Adhesion is expected to change significantly. In addition, the solid polymer electrolyte membrane is required to be as thin as possible in order to increase the internal impedance of the electrolyte membrane that causes output loss. However, it is difficult to obtain a bond that ensures adhesion between the electrolyte membrane thinned to 100 μm or less and the porous electrode substrate by hot pressing. Furthermore, the hot press is not suitable for continuous production and has a problem that it is difficult to apply at a production site because it is difficult to increase the area. Hydrocarbon electrolyte membrane materials into which sulfonic acid groups are introduced in addition to the Nafion membrane have been proposed, but all of them have poor oxidation resistance and still have problems in practical use.

  On the other hand, hybrid electrolyte membranes in which ion conductivity is imparted to an inorganic / organic polymer skeleton excellent in heat resistance and oxidation deterioration resistance have been proposed. In Japanese Patent No. 3103888 (Patent Document 2), Honma et al. Hydrolyze octane having bifunctional and trifunctional alkoxysilyl groups to give proton conductivity to a membrane having an alkylene skeleton having a crosslinked structure. Proposed solid electrolyte membrane. However, when alkoxysilane is hydrolyzed, the hydrolysis does not proceed completely, and the alkoxyl group remains, which may cause degradation due to hydrolysis due to water and hydrogen peroxide generated in the operating environment of the fuel cell. In terms of oxidative degradation, a fluorine-based solid electrolyte membrane represented by Nafion is most excellent. However, in a fluorine-based polymer, a crosslinkable group that achieves heat-curing properties is not generally known, and a hybrid electrolyte membrane that utilizes the excellent oxidative deterioration property of a fluorine-based solid electrolyte has not been studied so far. In this case, if a crosslinkable group can be introduced, the permeation problem of alcohol fuel during long-term use, which is one of the disadvantages of the Nafion membrane, can be prevented.

US Pat. No. 5,234,777 Japanese Patent No. 3103888

An object of the present invention is to solve the problems in conventional polymer electrolyte fuel cells, and is excellent in oxidation deterioration resistance, and can suppress deterioration and swelling due to permeation of alcohol, and is in close contact with an electrode catalyst. Proton conductive fluoropolyether composition for fuel cell electrolyte membrane, proton conductive fluoropolyether membrane, method for forming the membrane, fuel cell electrolyte membrane / electrode assembly using the composition, and fuel It is to provide a battery.

  In view of the above problems, the present inventors have conducted extensive research on various electrolyte membrane materials. As a result, the thermosetting perfluoropolyethers described in JP-A Nos. 2001-354768 and 2002-12769 are disclosed. By imparting ion conductivity to the rubber composition, an electrolyte membrane with low alcohol permeability and excellent resistance to oxidative degradation during operation is realized, and furthermore, an electrolyte membrane / electrode joint using a thinned electrolyte membrane It has been found that a low internal impedance value of the electrolyte membrane can be obtained by the body having excellent adhesion to the carbon on which the catalyst is supported due to the elastic properties possessed by the thermosetting electrolyte membrane.

More specifically, the present inventor, as an essential component of a composition for forming a solid electrolyte membrane,
(A) a fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain;
(B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule;
(C) hydrosilylation reaction catalyst,
(D) By combining proton conductivity-imparting agents (A) to (D), fluoropolyethylene having ion conductivity excellent in oxidation deterioration resistance and suppressed in deterioration and swelling due to permeation of alcohol. It has been found that ethers can be obtained, and that the ion conductive fluoropolyether membrane of the present invention is excellent in adhesion to catalyst-supported carbon.

  And after apply | coating the said electrolyte membrane on the catalyst layer containing the catalyst carrying | support carbon formed in the carbon paper surface used as a fuel diffusion electrode or an oxidizing agent diffusion electrode for the composition of this invention, another catalyst carrying | support carbon is used. After overlapping the electrolyte coating film of the present invention with an oxidant diffusion electrode or a fuel diffusion electrode provided with a catalyst layer containing, it is found that an electrolyte membrane / electrode assembly with low internal impedance is obtained by performing heat curing. It came to make this invention.

Accordingly, the present invention provides a proton conductive fluoropolyether composition for a fuel cell electrolyte membrane, a proton conductive fluoropolyether membrane obtained by curing the composition, a method for forming the same, and an electrolyte membrane / electrode assembly, A fuel cell is provided.
Claim 1:
(A) a fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain;
(B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule;
(C) hydrosilylation reaction catalyst,
(D) A proton conductive fluoropolyether composition for a fuel cell electrolyte membrane, comprising a proton conductivity imparting agent.
Claim 2:
2. The proton conductive fluoropolyether composition according to claim 1, wherein the structural unit of ether constituting the perfluoropolyether structure in component (A) is perfluoropropylene oxide.
Claim 3:
The proton conductive fluoropolyether composition according to claim 2, wherein the total number of repeating units of perfluoropropylene oxide having a perfluoropolyether structure in component (A) is 300 or less.
Claim 4:
A proton conductive fluoropolyether membrane for a fuel cell electrolyte membrane obtained using the proton conductive fluoropolyether composition according to any one of claims 1 to 3.
Claim 5:
A proton conductive fluoropolyether for a fuel cell electrolyte membrane comprising a step of applying the proton conductive fluoropolyether composition according to any one of claims 1 to 3 and a subsequent curing step. Method for forming a film.
Claim 6:
An electrolyte membrane / electrode assembly, wherein the proton conductive fluoropolyether membrane according to claim 4 is formed on a positive and / or negative gas diffusion electrode substrate used for hydrogen and / or direct methanol fuel cells.
Claim 7:
A fuel cell comprising the electrolyte membrane / electrode assembly according to claim 6.

  The proton conductive fluoropolyether composition of the present invention is excellent in adhesion, can form a cured film excellent in heat resistance and oxidation deterioration resistance, and is effective in forming an electrolyte membrane / electrode assembly for a fuel cell. .

The proton conductive fluoropolyether composition of the present invention comprises:
(A) a fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain;
(B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule;
(C) hydrosilylation reaction catalyst,
(D) Contains a proton conductivity-imparting agent.

The constitution of the present invention will be described in more detail. (A) which is a constituent of the composition of the present invention, has at least two alkenyl groups in one molecule, and has a perfluoropolyether structure in the main chain. The fluoropolyether compound represents a component described in JP-A Nos. 2002-12769 and 2001-354864. In this case, as the perfluoropolyether structure,
-C _d F _2d O-
(In the formula, d of each unit is an integer of 1 to 6 independently.)
And a compound represented by the following general formula (1).
(C _d F _2d O) _q (1)
(In the formula, q is an integer of 1 to 500, preferably 2 to 400, more preferably 10 to 200.)

Recurring units -C _d F _2d O- The represented by the above formula (1), for example, unit of the following, and the like. The perfluoroalkyl ether structure may be composed of one of these repeating units, or may be a combination of two or more.

-CF ₂ O-
-CF ₂ CF ₂ O-
-CF ₂ CF ₂ CF ₂ O-
-CF (CF ₃ ) CF ₂ O-
-CF ₂ CF ₂ CF ₂ CF ₂ O-
-CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ O-
-C (CF _{3) 2} O-

Of these, the following units are particularly preferred.
-CF ₂ O-
-CF ₂ CF ₂ O-
-CF ₂ CF ₂ CF ₂ O-
-CF (CF ₃ ) CF ₂ O-

  Especially, the structural unit of the ether constituting the perfluoropolyether is preferably perfluoropropylene oxide. In this case, the repeating unit is preferably 300 or less.

Further, the alkenyl group in the linear fluoropolyether compound (A) is preferably an alkenyl group having 2 to 8 carbon atoms, particularly 2 to 6 and having a CH ₂ ═CH— structure at the terminal, such as vinyl. Group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group and the like. Among them, vinyl group and allyl group are preferable. The alkenyl group may be present in the molecule, but is preferably bonded to both ends of the molecular chain. In this case, the alkenyl group is directly bonded to both ends of the main chain of the linear fluoropolyether compound. It may be bonded to the main chain via a divalent linking group as shown below.
_{-CH 2 -, - CH 2 O} -, - Y-NR-CO-
(However, Y is —CH ₂ — or a group represented by the following structural formula (Z), and R is a hydrogen atom, a methyl group, a phenyl group, or an allyl group.)

（ｏ，ｍ又はｐ位）

(O, m or p position)

  As said fluoro polyether compound, the linear thing shown by the following general formula (2) or (3) is preferable.

_{CH 2 = CH- (X) p} -Rf 0 - (X ') p -CH = CH 2 (2)
_{CH 2 = CH- (X) p} -Q-Rf 0 -Q- (X ') p -CH = CH 2 (3)
Wherein, X is -CH ₂ -, - CH ₂ O- or -Y-NR'-CO- (where, Y is -CH ₂ - group represented by or the structural formula (Z), R ' Is a hydrogen atom, a methyl group, a phenyl group or an allyl group.) And X ′ is —CH ₂ —, —OCH ₂ — or —CO—NR′—Y′— (where Y ′ is —CH _2). -Or a group represented by the following structural formula (Z '), R' represents the same meaning as described above), and Rf ⁰ represents a divalent perfluoropolyether structure or the above formula (1), is preferably one represented by _{(C d F 2d O) q} . p is independently 0 or 1, r is an integer of 2 to 6, Q is a divalent hydrocarbon group such as an alkylene group having 1 to 15 carbon atoms, and may contain an ether bond. ]

（ｏ，ｍ又はｐ位）

(O, m or p position)

  As such a linear fluoropolyether compound of component (A), those represented by the following general formula (4) are particularly suitable.

〔式中、Ｘ、Ｘ’は上記と同様の意味を示す。ｐは独立に０又は１、ｒは２〜６の整数、ｕは２〜６の整数。ｍ、ｎはそれぞれ０〜２００の整数である。〕

[Wherein, X and X ′ have the same meaning as described above. p is independently 0 or 1, r is an integer of 2-6, u is an integer of 2-6. m and n are each an integer of 0 to 200. ]

  The linear fluoropolyether compound of the above formula (4) preferably has a weight average molecular weight of 400 to 100,000, particularly 1,000 to 50,000.

Furthermore, in the present invention, in order to adjust the linear fluoropolyether compound of the above formula (4) to a desired weight average molecular weight according to the purpose, the above-mentioned linear fluoropolyether compound is previously incorporated in the molecule with an SiH group. It is also possible to use as a component (A) a product obtained by subjecting an organosilicon compound containing 2 to a hydrosilylation reaction by a conventional method and conditions, and extending the chain length.
In addition, it is preferable that the viscosity of (A) component is 3,000-15,000 mPa * s in 25 degreeC.

  Next, the component (B) acts as a crosslinking agent and chain extender for the component (A). The component (B) is not particularly limited as long as it is an organosilicon compound having at least two hydrogen atoms (H—Si structure) bonded to silicon atoms in one molecule. As such an organosilicon compound, those represented by the following general formula (5) are preferable.

〔式中、ｃは１，２，３又は４であり、Ｒは同一又は異種の炭素数１〜２０、好ましくは１〜６の１価の炭化水素基である。Ｚは水素原子もしくは−Ｑ−Ｍ、−Ｑ−Ｒｆ、−Ｑ−、−Ｒｆ’−、−Ｑ−Ｒｆ’−Ｑ−（但し、Ｑは炭素数１〜１５のアルキレン基等の２価の炭化水素基であり、エーテル結合を含んでいてもよく、Ｒｆは炭素数１〜４００の１価のパーフルオロアルキル基、パーフルオロオキシアルキル基、アルキル基又はオキシアルキル基であり、Ｒｆ’は炭素数１〜４００の２価のパーフルオロアルキレン基、パーフルオロオキシアルキレン基、アルキレン基、又はオキシアルキレン基である。）で表される。ｓは１，２又は３であり、ｔは０，１，２又は３である。ａ及びｂは０又は１，かつａとｂは同時に０とはならない。またＱは、上述したように、メチレン基、エチレン基、プロピレン基、へキシレン基等のアルキレン基や、これらアルキレン基の鎖中に−Ｏ−のエーテル結合が介在した基が挙げられる。〕

[Wherein, c is 1, 2, 3 or 4, and R is the same or different monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms. Z is a hydrogen atom or -QM, -Q-Rf, -Q-, -Rf'-, -Q-Rf'-Q- (where Q is a divalent alkylene group having 1 to 15 carbon atoms, etc. It is a hydrocarbon group and may contain an ether bond, Rf is a monovalent perfluoroalkyl group having 1 to 400 carbon atoms, a perfluorooxyalkyl group, an alkyl group or an oxyalkyl group, and Rf ′ is carbon. And a divalent perfluoroalkylene group, a perfluorooxyalkylene group, an alkylene group, or an oxyalkylene group having a number of 1 to 400. s is 1, 2 or 3, and t is 0, 1, 2 or 3. a and b are 0 or 1, and a and b are not 0 at the same time. Examples of Q include alkylene groups such as a methylene group, an ethylene group, a propylene group, and a hexylene group, and groups in which an —O— ether bond is interposed in the chain of these alkylene groups, as described above. ]

  As said organosilicon compound, the following are mentioned, for example. In the following formulae, Me represents a methyl group.

  In addition, as the component (B), siloxane having a hydrosilyl group is also exemplified. Specifically, α, ω-bis (dimethylhydrogensilyl) polydimethylsiloxane, α, ω-bis (trimethylsilyl) polymethylhydrogensiloxane, α, ω-bis (trimethylsilyl) poly (methylhydrogen) (dimethyl) ) Siloxane copolymer. A more preferred structure is shown below.

（式中、Ｍｅはメチル基を表し、ｎは２〜４５の整数を表す。）

(In the formula, Me represents a methyl group, and n represents an integer of 2 to 45.)

  In consideration of compatibility with component (A), dispersibility, and uniformity after curing, one or more monovalent perfluoroalkyl group, monovalent perfluorooxyalkyl group, 2 Those having a valent perfluoroalkylene group or a divalent perfluorooxyalkylene group can be used.

  These perfluoro (oxy) alkyl groups and perfluoro (oxy) alkylene groups preferably have 3 to 200 carbon atoms, particularly 15 to 60 carbon atoms, and may be directly bonded to a silicon atom. You may couple | bond together through the bivalent coupling group. Here, the divalent linking group may be an alkylene group, an arylene group, or a combination thereof, or an ether bond oxygen atom, an amide bond, a carbonyl bond, or the like interposed therebetween. The thing of 2-12 is preferable.

  Further, the monovalent or divalent fluorine-containing substituent in the organosilicon compound of component (B), that is, a monovalent containing a perfluoroalkyl group, a perfluorooxyalkyl group, a perfluoroalkylene group or a perfluorooxyalkylene group. Examples of the monovalent substituent R bonded to the silicon atom other than the organic group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, an octyl group, and a decyl group, a vinyl group An alkenyl group such as an allyl group, an aryl group such as a phenyl group, a tolyl group and a naphthyl group, an aralkyl group such as a benzyl group and a phenylethyl group, or a part of hydrogen atoms of these groups is a chlorine atom, a cyano group, etc. Substituted, for example, unsubstituted or substituted of 1 to 20 carbon atoms such as chloromethyl group, chloropropyl group, cyanoethyl group It includes hydrocarbon groups. Further, the number of silicon atoms in one molecule in the organosilicon compound is not particularly limited, but usually 2 to 60, particularly 3 to 30 is preferable.

  The blending amount of the component (B) is usually a hydrosilyl group in the component (B), that is, a SiH group, with respect to 1 mol of an alkenyl group such as a vinyl group, an allyl group, or a cycloalkenyl group contained in the component (A). Is preferably 0.5 to 5 mol, more preferably 1 to 2 mol. When the blending amount of the component (B) is too small, the degree of crosslinking may be insufficient, foaming, heat resistance, compression set characteristics, and the like may be deteriorated.

  As the hydrosilylation reaction catalyst of component (C), transition metals, for example, platinum group metals such as Pt, Rh, and Pd, and compounds of these transition metals are preferably used. In the present invention, platinum compounds that are relatively easily available are preferably used. Specific examples of the platinum compound include chloroplatinic acid or a complex of chloroplatinic acid and an olefin such as ethylene, a complex of alcohol or vinylsiloxane, platinum / silica, alumina, or carbon. It is not limited.

Rhodium, ruthenium, iridium, palladium compounds and the like are known as platinum group compounds other than platinum compounds. For example, RhCl (PPh ₃ ) ₃ , RhCl (CO) (PPh ₃ ) ₂ , RhCl (C ₂ H _4). ) ₂ , Ru ₃ (CO) ₁₂ , IrCl (CO) (PPh ₃ ) ₂ , Pd (PPh ₃ ) ₄ (Ph represents a phenyl group).

  The amount of these catalysts used is not particularly limited, and a desired curing rate can be obtained with a normal amount of catalyst. However, in order to obtain an economical viewpoint or a good cured product, a curable composition is used. It is good to set it as the range of about 0.1-1,000 ppm (platinum group metal conversion) with respect to the total amount of things, More preferably, 0.1-500 ppm (platinum group metal conversion) grade.

  In the curable composition of the present invention, in addition to the component (B), in addition to the component (B), the H-Si-OSi structure or formula is used for adjusting workability, rubber physical properties, etc. An organosilicon compound having a structure other than (5) and having at least two SiH structures in one molecule can be blended at an arbitrary ratio. The SiH group-containing organosilicon compound not corresponding to the formula (5) is not particularly limited as long as it has two or more SiH groups in one molecule, and has a chain shape, a ring shape, a network shape, or the like. It may be taken.

  In the case where an organosilicon compound having a hydrosilyl group, that is, a SiH group having a structure other than the formula (5) is added as a crosslinking agent or chain extender of the component (A), a vinyl group usually contained in the component (A), The total amount of SiH groups is preferably 0.5 to 5 moles, more preferably 1 to 2 moles per mole of alkenyl groups in the allyl group and cycloalkenyl group. If the amount of SiH group is too small, the degree of cross-linking may be insufficient, and if it is too large, chain length extension takes precedence, curing becomes insufficient, foaming, heat resistance, compression set characteristics, etc. It may get worse.

  The compounding quantity of the organosilicon compound which has SiH structure other than Formula (5) with respect to (B) component is not specifically limited, It can set arbitrarily according to a use.

  Next, as the component (D), a so-called acid compound that releases protons is used. Here, examples of the acid compound as the proton conductivity-imparting agent include phosphoric acid, sulfuric acid, sulfonic acid, carboxylic acid, boric acid, heteropolyacid, and derivatives thereof. In the present invention, two or more of these acids or derivatives thereof may be used in combination. Among these, it is preferable to use heteropolyacid. The heteropolyacid refers to an inorganic oxo acid, and among them, those having a Keggin structure or a Dawson structure such as tungstophosphoric acid, molybdophosphoric acid, tungstosilicic acid and the like are preferably used. These heteropolyacids are retained in the composition by the perfluoroether skeleton and the polarity of the urethane bond. When this proton conductivity-imparting agent is added to the composition as the component (D), the amount is preferably 5 to 150 parts by mass with respect to 100 parts by mass of the (A) component perfluoropolyether. Usually, since it has crystal water, it can be added without adding water, but water can be added if necessary. An ionic liquid may be added to increase the retention of the proton conductivity-imparting agent in the composition or to increase proton conductivity. Examples of the ionic liquid include, but are not limited to, a pyridine-based ionic liquid, an alicyclic amine system, and an aliphatic amine system.

  When the component (D), the proton conductivity-imparting agent, is used independently without being mixed with the composition, a coating film obtained using the composition containing the components (A) to (C) of the present invention Can be obtained by immersing them in a proton conductivity-imparting agent or a solution containing a proton conductivity-imparting agent, or by subjecting them to a proton conductivity-imparting process similar to these, such as exposure to vapor.

  The heat curing step may be before or after the proton conductivity imparting step. The temperature condition at the time of heat curing is selected in the range of 100 to 200 ° C. according to a conventional method using a hydrosilylation catalytic reaction.

  Further, in the present invention, an inorganic compound such as oxide, nitride, carbide or the like is added as a filler for the purpose of retaining a proton conductivity-imparting agent or for preventing the permeation of hydrogen or alcohol, water, or oxygen of the fuel cell. can do. Specific examples of the filler include boron nitride, silicon carbide, and silica.

  In this case, the proton conductive fluoropolyether composition is preferably prepared as a liquid, and this is applied to a suitable substrate and cured to form a proton conductive fluoropolyether film. be able to. The curing conditions are as described above. The thickness of the cured film is appropriately selected, but is usually 10 to 200 μm, particularly 30 to 100 μm.

  The proton conductive fluoropolyether composition or membrane of the present invention suppresses oxidative degradation due to hydrogen peroxide, particularly as an electrolyte membrane / electrode assembly in a polymer electrolyte fuel cell using hydrogen or methanol as a fuel. In addition, it can be suitably used as a material having a thermosetting property with less adhesion of methanol as a fuel even during long-term use and excellent adhesion to the solid catalyst of the electrode layer. Electrolyte membrane / electrode assembly obtained from a process including a method of forming the above proton conductive fluoropolyether membrane on a positive and / or negative gas diffusion electrode substrate used for direct methanol fuel cell, and this assembly A fuel cell comprising: In this case, the gas diffusion electrodes for the positive electrode and the negative electrode can have a known configuration, and the gas diffusion electrode material may be a known material. Further, the configuration of the fuel cell other than the gas diffusion electrode can be a known configuration. The fuel cell here is of a type that uses hydrogen or methanol as fuel, and methanol may be diluted with water at a desired concentration.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following examples, the viscosity is a value of 25 ° C.

[Example 1]
The polymer represented by the following general formula (i) (viscosity 8,500 mPa · s, weight average molecular weight 22,000, vinyl group content 0.009 mol / 100 g) is contained in 100 parts by mass, and is represented by the following formula (ii). 2.64 parts by mass of a fluorine organosilicon compound, a toluene solution of a catalyst obtained by modifying chloroplatinic acid with CH ₂ ═CHSi (Me) ₂ OSi (Me) ₂ CH═CH ₂ (platinum concentration: 1.0 part by mass) 0.2 0.4 parts by weight of a 50% toluene solution of ethynylcyclohexanol and 50 parts by weight of silicotungstic acid (SiW ₁₂ O ₄₀ , manufactured by Wako Pure Chemical Industries, Ltd.) were added and kneaded. The obtained composition was defoamed under reduced pressure, a film having a thickness of about 200 μm was formed on a 5 cm square frame by a doctor blade method, and press cured at a press condition of 1 kg / cm ² and 150 ° C. for 10 minutes. The thickness of the obtained test piece was 150 μm. The test piece was used for measurement of ionic conductivity, alcohol permeation amount, and elution amount by Fenton reagent.

[Example 2]
The polymer represented by the above general formula (i) (viscosity 8,500 mPa · s, weight average molecular weight 22,000, vinyl group amount 0.009 mol / 100 g) is contained in 100 parts by mass of the above formula (ii). 2.64 parts by mass of a fluorine organosilicon compound, a toluene solution of a catalyst obtained by modifying chloroplatinic acid with CH ₂ ═CHSi (Me) ₂ OSi (Me) ₂ CH═CH ₂ (platinum concentration: 1.0 part by mass) 0.2 0.4 parts by mass of a 50% toluene solution of ethynylcyclohexanol and 50 parts by mass of phosphotungstic acid / n hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were added and kneaded. The obtained composition was defoamed under reduced pressure, a film having a thickness of about 200 μm was formed on a 5 cm square frame by a doctor blade method, and press cured at a press condition of 1 kg / cm ² and 150 ° C. for 10 minutes. The thickness of the obtained test piece was 150 μm. The test piece was used for measurement of ionic conductivity, alcohol permeation amount, and elution amount by Fenton reagent.

[Example 3]
A platinum catalyst (carbon carrying ValcanXC72 (E-Tek Inc) Pt = 20 wt%, Pt: 0.34 mg / cm ² ) was kneaded with a 5% isopropyl alcohol solution (manufactured by Aldrich) of Nafion to form a paste. . This catalyst paste was coated on carbon paper (TGPH090 (manufactured by Toray Industries, Inc.), and then dried on a hot plate at 120 ° C. for 5 minutes, and the composition obtained in Example 1 was added by a doctor blade method. A film having a thickness of about 70 μm was applied, which was used as an anode side electrode, and a platinum catalyst (Valcan XC72 (E-Tek Inc) Pt = 20 wt%, Pt: similarly) with a 5% isopropyl alcohol solution (manufactured by Aldrich) of a Nafion film. 0.34 mg / cm ² ) is kneaded and a paste-form catalyst paste is applied onto carbon paper (TGPH090, manufactured by Toray Industries, Inc.) and then dried on a hot plate at 120 ° C. for 5 minutes. A film having a thickness of about 70 μm was applied to the composition obtained in Example 1 by the doctor blade method. Theft could be.

[Comparative Example 1]
A Nafion 117 (manufactured by DuPont: 175 μm thick) membrane was cut on a 5 cm square frame. The thickness of the obtained test piece was 185 μm. The test piece was used for measurement of ionic conductivity, alcohol permeation amount, and elution amount by Fenton reagent.

The results are shown in Table 1.

Measuring method:
* 1 Methanol permeation amount Measured according to the diffusion cell method. The structure is described in J.H. Won et al. / According to Journal of Membrane Science 214 (2003) 245-257. The measurement conditions were room temperature (25 ° C.).
* 2 Fenton's reagent was a hydrogen peroxide concentration of 3%, Fe ²⁺ 200ppm aqueous solution was transferred to a sealed container, and the sample was immersed and left in a constant temperature bath at 40 ° C. After elapse of a predetermined time, the sample was washed with water, dried in a constant temperature bath at 60 ° C., and the mass reduction rate by this test was determined by weighing.
* 3 Proton conductivity was measured after immersion of all proton conducting membranes in pure water overnight. An impedance gain phase analyzer 1260 made by Schulberger Technologies was used. A platinum plate was used as the electrode, and the measurement area was 1 cm ² .

From the results of Table 1 showing the characteristics of the electrolyte membranes and the electrolyte membrane / electrode assemblies obtained in Examples and Comparative Examples, the proton conductive fluoropolyether electrolyte membrane according to the present invention has excellent alcohol swelling resistance and oxidation resistance. The deterioration characteristics, ionic conductivity, and the electrolyte membrane / electrode assembly for a fuel cell using the same realized low internal impedance. By using this electrolyte membrane or the electrolyte membrane / electrode assembly, a fuel cell having excellent reliability can be provided.

Claims (7)

(A) a fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain;
(B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule;
(C) hydrosilylation reaction catalyst,
(D) A proton conductive fluoropolyether composition for a fuel cell electrolyte membrane, comprising a proton conductivity imparting agent.   2. The proton conductive fluoropolyether composition according to claim 1, wherein the structural unit of ether constituting the perfluoropolyether structure in component (A) is perfluoropropylene oxide.   The proton conductive fluoropolyether composition according to claim 2, wherein the total number of repeating units of perfluoropropylene oxide having a perfluoropolyether structure in component (A) is 300 or less. A proton conductive fluoropolyether membrane for a fuel cell electrolyte membrane obtained using the proton conductive fluoropolyether composition according to any one of claims 1 to 3. A proton conductive fluoropolyether for a fuel cell electrolyte membrane comprising a step of applying the proton conductive fluoropolyether composition according to any one of claims 1 to 3 and a subsequent curing step. Method for forming a film.   An electrolyte membrane / electrode assembly, wherein the proton conductive fluoropolyether membrane according to claim 4 is formed on a positive and / or negative gas diffusion electrode substrate used for hydrogen and / or direct methanol fuel cells.   A fuel cell comprising the electrolyte membrane / electrode assembly according to claim 6.