JP2003317750A - Manufacturing method of stacked body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an electrolyte layer without infiltrating onto an electrode layer, and to provide a stacked body having high power generating characteristics as an electrode structure. <P>SOLUTION: In a manufacturing method of the stacked body, proton conductive polymer solution or fluid dispersion containing 25 to 50 wt.% of moisture is coated on the electrode layer, they are dried to form a thin film made of the proton conductive polymer, proton conductive polymer solution or fluid dispersion containing 25 wt.% or lower of moisture is coated on the thin film, and they are dried to manufacture a laminated body composed of the electrode layer and the electrolyte layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a laminate comprising an electrode layer and an electrolyte layer suitable for a fuel cell.

[0002]

2. Description of the Related Art A fuel cell usually has an electrolyte layer formed on an electrode layer. Conventionally, in order to integrally form an electrode and an electrolyte layer, carbon carrying a hydrogen reduction catalyst is prepared in advance, the catalyst paste is applied to carbon paper and heat treated to form an electrode layer, and two film-like electrolytes are formed. It was sandwiched between the electrode layers of No. 2 and was hot-pressed to perform three-layer bonding of anode / electrolyte layer / cathode.

However, in such a three-layer joining method, the adhesion of each layer is poor, and it takes time to integrate the three layers, so that each layer is individually formed and is not suitable for mass production. There was a problem. Further, the high heat-resistant electrolyte layer, which has been in high demand in recent years, has a problem in that the thermoplasticity of the electrolyte layer is insufficient and the joining process is limited.

Therefore, a method has been proposed in which, after forming an electrode layer, a varnish in which a compound for forming an electrolyte is dissolved in a solvent is applied onto the electrode layer and dried.
However, the above-mentioned varnish in which a highly heat-resistant electrolyte is dissolved penetrates into the electrode layer when applied on the electrode layer, and there is a problem that the power generation performance is not sufficiently exhibited.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a laminate which can form an electrolyte layer on an electrode layer without penetrating and has good power generation characteristics as an electrode structure.

[0006]

According to the present invention, the following method for producing a laminate is provided to achieve the above object of the present invention. (1) A proton conductive polymer solution or dispersion having a water content of 25 to 50% by weight is applied on the electrode layer and dried to form a thin film made of the proton conductive polymer.
Next, a method for producing a laminate comprising an electrode layer and an electrolyte layer, which comprises applying a proton-conducting polymer solution or dispersion having a water content of less than 25% by weight onto the thin film and drying. (2) The method for producing a laminate according to (1), wherein the proton conductive polymer is sulfonated polyarylene.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a laminate according to the present invention will be specifically described below. In the present invention, a laminate is manufactured by applying two types of proton conductive polymer solutions or dispersions having different water contents on the electrode layer and drying. (Electrode layer) In the present invention, the electrode layer is usually formed by applying a paste comprising catalyst fine particles having a hydrogen reducing ability and a proton conductive polymer electrolyte component supported on conductive porous particles to a gas diffusion electrode substrate. Is prepared by.

As the conductive porous particles, those having a high structure and a large surface area such as Ketjen black and acetylene black are used. As a catalyst for reducing hydrogen,
Noble metals such as platinum, palladium, ruthenium and rhodium, and these metals and chromium, molybdenum, tungsten,
Examples thereof include alloys with metals such as titanium, zirconium and cobalt. The supported amount of the catalyst metal is usually 10 to 60% by weight based on the conductive porous particles. For the electrode, the paste is applied to a porous gas diffusion electrode substrate such as carbon paper or carbon cloth by a coating method such as a doctor blade or spray.

The thickness of the electrode layer is usually 5 to 100 μm, preferably 5 to 50 μm. (Proton-Conducting Polymer) In the present invention, as the proton-conducting polymer for forming the electrolyte layer, sulfonated polyarylene, sulfonated polyarylene ether, sulfonated polyarylene ketone, sulfonated polyether ether ketone, polyimide, Examples thereof include sulfonated polybenzomindazole and sulfonated products of perfluorohydrocarbon-based tetrafluoroethylene copolymer, but use of sulfonated polyarylene to obtain an electrode structure having good electrical characteristics. Is preferred.

The sulfonated polyarylene includes a monomer (A) represented by the following general formula (A) and a general formula (B-
A sulfonated polymer obtained by reacting with at least one monomer (B) selected from 1) to (B-4) is used.

[0011]

[Chemical 1]

In the formula (A), R to R'may be the same or different from each other, and a halogen atom excluding a fluorine atom or --OSO ₂ Z (where Z is an alkyl group, a fluorine-substituted alkyl group or an aryl group). Is shown). Examples of the alkyl group represented by Z include a methyl group and an ethyl group, examples of the fluorine-substituted alkyl group include a trifluoromethyl group, and examples of the aryl group include a phenyl group and a p-tolyl group.

R ^{1 to} R ⁸ may be the same or different and each is at least one atom selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group and an aryl group, or Indicates a group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group and a hexyl group, and a methyl group and an ethyl group are preferable.

Examples of the fluorine-substituted alkyl group include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group and a perfluorohexyl group. A fluoroethyl group and the like are preferable. Examples of the allyl group include a propenyl group,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.

X represents a divalent electron-withdrawing group, and examples of the electron-withdrawing group include --CO--, --CONH--,-(C
F ₂ ) _p- (where p is an integer of 1 to 10), -C
_{(CF 3) 2 -, -} COO -, - SO -, - SO 2 - , and the like. The electron-withdrawing group is Hammett (Ha
mmett) When the substituent constant is m-position of the phenyl group, 0.0
A group having a value of 6 or more and 0.01 or more in the case of the p-position.

Y represents a divalent electron-donating group, and examples of the electron-donating group include -O-, -S-, -CH = CH.
-, -C≡C- and the following formula

[0017]

[Chemical 2]

Examples include groups represented by: n is 0 or a positive integer, and the upper limit is usually 100, preferably 8
It is 0. Specific examples of the monomer represented by the general formula (A) include 4,4′-dichlorobenzophenone,
4,4'-dichlorobenzanilide, bis (chlorophenyl) difluoromethane, 2,2-bis (4-chlorophenyl) hexafluoropropane, 4-chlorobenzoic acid-
4-chlorophenyl, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, compounds in which a chlorine atom is replaced by a bromine atom or an iodine atom in these compounds, and a halogen atom substituted at the 4-position in these compounds is Examples thereof include compounds substituted at the 3-position.

Specific examples of the monomer represented by the general formula (A) include 4,4'-bis (4-chlorobenzoyl) diphenyl ether and 4,4'-bis (4-chlorobenzoylamino) diphenyl ether. 4,4'-
Bis (4-chlorophenylsulfonyl) diphenyl ether, 4,4'-bis (4-chlorophenyl) diphenyl ether dicarboxylate, 4,4'-bis [(4-chlorophenyl) -1,1,1,3,3,3- Hexafluoropropyl] diphenyl ether, 4,4'-bis [(4-
Chlorophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4'-bis [(4
-Chlorophenyl) tetrafluoroethyl] diphenyl ether, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom in these compounds, a compound in which a halogen atom substituted in the 4-position of these compounds is substituted in the 3-position, and further these compounds At least one of the groups substituted at the 4-position of the diphenyl ether is 3
Compounds substituted at the position may be mentioned.

Further, as the monomer represented by the general formula (A), 2,2-bis [4- {4- (4-chlorobenzoyl) phenoxy} phenyl] -1,1,1,3,3,
3-hexafluoropropane, bis [4- {4- (4-
Chlorobenzoyl) phenoxy} phenyl] sulfone,
And a compound represented by the following formula.

[0021]

[Chemical 3]

The monomer represented by the general formula (A) is
For example, it can be synthesized by the following method. First, in order to convert the bisphenol linked with an electron-withdrawing group into the corresponding alkali metal salt of bisphenol, dielectrics such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenylsulfone, and dimethyl sulfoxide are used. An alkali metal such as lithium, sodium and potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate and the like are reacted in a highly polar solvent.

Usually, an alkali metal or the like is reacted with the hydroxyl group of phenol with a slight excess, and usually 1.1 to 2 times the equivalent amount is used. Preferably, it is 1.2 to 1.5 times equivalent. At this time, benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene,
An aromatic dihalide compound substituted with a halogen atom such as fluorine or chlorine activated by an electron-withdrawing group in the coexistence of a water-azeotropic solvent such as dioxane, tetrahydrofuran, anisole, or phenetole, for example, 4,4 '-Difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-chlorofluorobenzophenone, bis (4-chlorophenyl) sulfone, bis (4-fluorophenyl) sulfone, 4-fluorophenyl-4'-chlorophenylsulfone, Bis (3-nitro-4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, hexafluorobenzene, decafluorobiphenyl, 2,5-difluorobenzophenone, 1,3-bis (4 -Chlorobenzoyl) benzene etc. . In terms of reactivity,
Fluorine compounds are preferable, but in consideration of the following aromatic coupling reaction, it is necessary to assemble the aromatic nucleophilic substitution reaction so that the terminal is a chlorine atom. The active aromatic dihalide is used in an amount of 2 to 4 times, preferably 2.2 to 2.8 times the mol of bisphenol. Before the aromatic nucleophilic substitution reaction, an alkali metal salt of bisphenol may be used in advance. The reaction temperature is 60 ° C to 300 ° C, preferably 80 ° C to 250 ° C. Reaction time is 15
It is in the range of minutes to 100 hours, preferably 1 hour to 24 hours. The most preferable method is the following formula

[0024]

[Chemical 4]

A chlorofluoro compound having one halogen atom having different reactivity is used as the active aromatic dihalide represented by the formula (wherein X is as defined for the general formula (A)). It is convenient to obtain the desired activated terminal chloro compound because the nucleophilic substitution reaction with the phenoxide takes place preferentially on the atom.

As another method for synthesizing the monomer represented by the general formula (A), a nucleophilic substitution reaction and an electrophilic substitution reaction are combined as described in JP-A-2-159 to obtain a desired electron. There is a method of synthesizing a flexible compound composed of an attractive group and an electron donating group. Specifically, an aromatic dihalide activated with an electron-withdrawing group, for example, bis (4-
The chlorophenyl) sulfone is subjected to a nucleophilic substitution reaction with a phenol compound to give a bisphenoxy compound. Then, the substituted compound is subjected to, for example, a Friedel-Crafts reaction with 4-chlorobenzoic acid chloride to obtain the target compound.

The compounds exemplified above can be applied to the aromatic dihalide activated by the electron-withdrawing group used here. The phenol compound may be substituted,
From the viewpoint of heat resistance and flexibility, unsubstituted compounds are preferable.
When the phenol compound is substituted, it is preferably an alkali metal salt, and as the alkali metal compound that can be used when substituting the phenol compound, the compounds exemplified above can be used. The amount of the alkali metal compound used is 1.2 to 2 times mol per mol of phenol. In the reaction, the above polar solvent or an azeotropic solvent with water can be used.

To obtain the target compound, a bisphenoxy compound is used as a chlorobenzoic acid as an acylating agent in the presence of an activator of a Friedel-Crafts reaction of a Lewis acid such as aluminum chloride, boron trifluoride or zinc chloride. React with chloride. Chlorobenzoic acid chloride is 2 to 4 times mol, preferably 2.2 to 2 times the mol of the bisphenoxy compound.
Use of 3 times mole. The Friedel-Crafts activator is used in an amount of 1.1 to 2 times equivalent to 1 mol of the active halide compound such as chlorobenzoic acid as an acylating agent. The reaction time is in the range of 15 minutes to 10 hours, and the reaction temperature is in the range of -20 ° C to 80 ° C. As the solvent to be used, chlorobenzene, nitrobenzene or the like which is inert to the Friedel-Crafts reaction can be used.

Further, in the general formula (A), the monomer (A) in which n is 2 or more is, for example, bisphenol serving as a source of the etheric oxygen which is the electron donating group Y in the general formula (A), An electron-withdrawing group X,> C = O,
-SO ₂ -, and / or> C (CF ₃₎ was Kumiawashi and _2, specifically 2,2-bis (4-hydroxyphenyl) 1,1,1,3,3,3-hexafluoropropane Propane, 2,2-bis (4-hydroxyphenyl) ketone,
A substitution reaction of an alkali metal salt of bisphenol such as 2,2-bis (4-hydroxyphenyl) sulfone with an excess amount of an active aromatic halogen compound such as 4,4-dichlorobenzophenone or bis (4-chlorophenyl) sulfone is carried out by N- It can be obtained by sequentially polymerizing the above monomers in the presence of a polar solvent such as methyl-2-pyrrolidone, N, N-dimethylacetamide and sulfolane.

Examples of such a monomer (A) include compounds represented by the following formula.

[0031]

[Chemical 5]

[0032]

[Chemical 6]

[0033]

[Chemical 7]

In the above, n is 2 or more, preferably 2
~ 100. Next, the monomers represented by formulas (B-1) to (B-4) will be described.

[0035]

[Chemical 8]

In the formula, R and R'may be the same as or different from each other and represent the same groups as R and R'in the general formula (A). R ^{9 to} R ¹⁵ may be the same or different and each represents at least one atom or group selected from the group consisting of hydrogen atom, fluorine atom and alkyl group. Examples of the alkyl group represented by R ^{9 to} R ¹⁵ include the same as the alkyl groups represented by R ^{1 to} R ⁸ in the general formula (A).

M represents 0, 1 or 2. X represents a divalent electron-withdrawing group selected from the same group as that shown as X in the above general formula (A). Y is Y in the above general formula (A)
Represents a divalent electron-donating group selected from the same group as shown in.

W represents at least one group selected from the group consisting of phenyl group, naphthyl group and groups represented by the following formulas (C-1) to (C-3).

[0039]

[Chemical 9]

In the formula, A represents an electron donating group or a single bond. Examples of the electron donating group include a divalent electron donating group selected from the same group as that shown as Y in the above general formula (A). R ¹⁶ and R ¹⁷ represent an atom or a group selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group. Examples of the alkyl group and aryl group represented by R ¹⁶ and R ¹⁷ include those similar to the alkyl group and aryl group represented by R ^{1 to} R ⁸ in the general formula (A).

R ^{18 to} R ²⁶ may be the same or different and each represents at least one atom or group selected from the group consisting of hydrogen atom, fluorine atom and alkyl group. q represents 0 or 1. Examples of the monomer represented by the general formula (B-1) include compounds represented by the following formula.

[0042]

[Chemical 10]

More specifically, examples of the compound represented by the general formula (B-1) include compounds represented by the following formula.

[0044]

[Chemical 11]

[0045]

[Chemical 12]

Further, compounds in which chlorine atom is replaced with bromine atom or iodine atom in the above compounds can be exemplified. From above (B-2), (B-
3), (B-4)

[0047]

[Chemical 13]

In the formulas (B-2) to (B-4), R and R'may be the same or different from each other and represent the same groups as R and R'in the general formula (A). R ²⁷ ~ R ³⁴
May be the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an aryl group or a group represented by the following general formula (D).

[0049]

[Chemical 14]

In the formula (D), R ^{35 to} R ^{43, which} may be the same or different, each represents a hydrogen atom, a halogen atom, an alkyl group or a fluorine-substituted alkyl group. R ^{27 to} R ³⁴ , R ³⁵
Examples of the alkyl group and the fluorine-substituted alkyl group represented by R ⁴³ to R ⁴³ include the same groups as the alkyl group and the fluorine-substituted alkyl group represented by R ^{1 to} R ⁸ . Examples of the aryl group represented by R ^{27 to} R ³⁴ include the same groups as the aryl group represented by R ^{1 to} R ⁸ .

X represents a divalent electron-withdrawing group selected from the same group as that shown as X in the above general formula (A).
Y represents a divalent electron donating group selected from the same group as that shown as Y in the above general formula (A). Specific examples of the monomer represented by the above general formula (B-2) include p-dichlorobenzene, p-dimethylsulfonyloxybenzene, 2,5-dichlorotoluene, 2,5-dimethylsulfonyloxybenzene, and the like. 2,5-dichloro-p-
Xylene, 2,5-dichlorobenzotrifluoride,
Examples thereof include 1,4-dichloro-2,3,5,6-tetrafluorobenzene, and compounds in which chlorine atom is replaced with bromine atom or iodine atom in these compounds.

Specific examples of the monomer represented by the above general formula (B-3) include, for example, 4,4'-dimethylsulfonyloxybiphenyl, 4,4'-dimethylsulfonyloxy-3,3'-diene. Propenyl biphenyl, 4,4'-dibromobiphenyl, 4,4'-diiodobiphenyl, 4,4'-dimethylsulphonyloxy-3,3'-dimethylbiphenyl, 4,4'-dimethylsulphonyloxy-3, 3'-difluorobiphenyl, 4,4'-dimethylsulfonyloxy-3,3 ', 5,5'-tetrafluorobiphenyl, 4,4'
-Dibromooctafluorobiphenyl, 4,4'-dimethylsulfonyloxyoctafluorobiphenyl and the like.

Specific examples of the monomer represented by the above general formula (B-4) include m-dichlorobenzene and m-dichlorobenzene.
Dimethylsulfonyloxybenzene, 2,4-dichlorotoluene, 3,5-dichlorotoluene, 2,6-dichlorotoluene, 3,5-dimethylsulfonyloxytoluene, 2,6-dimethylsulfonyloxytoluene, 2,4
-Dichlorobenzotrifluoride, 3,5-dichlorobenzotrifluoride, 1,3-dibromo-2,4,5,
Examples thereof include 6-tetrafluorobenzene, and compounds in which a chlorine atom is replaced with a bromine atom or an iodine atom in these compounds.

The polyarylene reacts the above-mentioned monomers in the presence of a catalyst, and the catalyst used is a catalyst system containing a transition metal compound, and the catalyst system is a compound which becomes a transition metal salt and a ligand. (Hereinafter, "ligand component"
Say. ), Or a transition metal complex in which a ligand is coordinated (including a copper salt), and a reducing agent as essential components, and a “salt” may be added to increase the polymerization rate.

Here, as the transition metal salt, nickel compounds such as nickel chloride, nickel bromide, nickel iodide, and nickel acetylacetonate; palladium chloride,
Palladium compounds such as palladium bromide and palladium iodide; iron compounds such as iron chloride, iron bromide and iron iodide; cobalt compounds such as cobalt chloride, cobalt bromide and cobalt iodide. Of these, nickel chloride and nickel bromide are particularly preferable.

Examples of the ligand component include triphenylphosphine, 2,2'-bipyridine, 1,5-cyclooctadiene and 1,3-bis (diphenylphosphino) propane. Of these, triphenylphosphine and 2,2'-bipyridine are preferable. The compound that is the ligand component may be used alone or in combination of two or more.

Further, examples of the transition metal complex having a ligand coordinated include nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis (triphenylphosphine), Nickel nitrate bis (triphenylphosphine),
Nickel chloride (2,2'-bipyridine), nickel bromide (2,2'-bipyridine), nickel iodide (2,2'-bipyridine), nickel nitrate (2,2'-bipyridine), bis (1, 5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel, tetrakis (triphenylphosphine) palladium, etc. are mentioned. Of these, nickel chloride bis (triphenylphosphine) and nickel chloride (2,2′-bipyridine) are preferable.

Examples of the reducing agent that can be used in the above catalyst system include iron, zinc, manganese, aluminum, magnesium, sodium, calcium and the like. Of these, zinc, magnesium and manganese are preferable. These reducing agents can be further activated and used by bringing them into contact with an acid such as an organic acid.

As the "salt" which can be used in the above catalyst system, sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide and sodium sulfate, potassium fluoride, potassium chloride, odor, etc. Examples thereof include potassium compounds such as potassium iodide, potassium iodide and potassium sulfate; ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and tetraethylammonium sulfate. Of these, sodium bromide, sodium iodide, potassium bromide, tetraethylammonium bromide and tetraethylammonium iodide are preferred.

The proportion of each component used is usually 0.0001 to 10 moles, preferably 0.01 to 10 moles of the transition metal salt or transition metal complex, relative to 1 mole of the total of the above monomers.
It is 0.5 mol. If it is less than 0.0001 mol, the polymerization reaction may not proceed sufficiently, while if it exceeds 10 mol, the molecular weight may decrease. When a transition metal salt and a ligand component are used in the catalyst system, the ratio of the ligand component used is usually 0.1 to 100 mol, preferably 1 to 10 mol, based on 1 mol of the transition metal salt. is there. If it is less than 0.1 mol, the catalytic activity may be insufficient, whereas if it exceeds 100 mol, the molecular weight may be lowered.

The ratio of the reducing agent to be used is usually 0.1 to 100 mol, preferably 1 to 10 mol, based on 1 mol of the total amount of the above monomers. If it is less than 0.1 mol, the polymerization may not proceed sufficiently, and if it exceeds 100 mol,
Purification of the resulting polymer may be difficult. Furthermore, when a "salt" is used, its use ratio is usually 0.001 to 100 mol, preferably 0.01 to 1 mol, based on 1 mol of the total of the above monomers. If it is less than 0.001 mol, the effect of increasing the polymerization rate may be insufficient, and if it exceeds 100 mol, purification of the resulting polymer may be difficult.

Polymerization solvents that can be used include
For example, tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N
-Dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam and the like can be mentioned. Of these, tetrahydrofuran, N, N-
Dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are preferred. It is preferable to use these polymerization solvents after drying them sufficiently.

The total concentration of the above-mentioned monomers in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40% by weight. The polymerization temperature during the polymerization is usually 0.
-200 degreeC, Preferably it is 50-120 degreeC. Also,
The polymerization time is usually 0.5 to 100 hours, preferably 1
~ 40 hours.

Thus, the monomer (A) represented by the general formula (A) and the general formulas (B-1) to (B-
A polymerization solution containing polyarylene is obtained by polymerizing at least one kind of monomer (B) selected from the monomers represented by 4). Next, the sulfonated polyarylene, which is preferably used in the conductive membrane of the present invention, can be obtained by introducing a sulfonic acid group into the above-mentioned polyarylene having no sulfonic acid group by using a sulfonating agent by a conventional method. it can.

As a method of introducing a sulfonic acid group, for example, a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, sodium hydrogen sulfite, etc. Can be used for sulfonation under known conditions [Polymer Preprints,
Japan, Vol.42, No.3, p.730 (1993); Polymer Preprint
s, Japan, Vol.42, No.3, p.736 (1994); Polymer Preprin
ts, Japan, Vol. 42, No. 7, p. 2490 to 2492 (1993)].

That is, as the reaction conditions for the sulfonation, the copolymer having no sulfonic acid group is reacted with the sulfonating agent in the absence of a solvent or in the presence of a solvent. Examples of the solvent include hydrocarbon solvents such as n-hexane, ether solvents such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide and dimethylsulfoxide, and tetrachloroethane, dichloroethane, chloroform and chloride. Examples thereof include halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but usually-
It is 50 to 200 ° C, preferably -10 to 100 ° C.
The reaction time is usually 0.5 to 1,000 hours, preferably 1 to 200 hours.

The amount of sulfonic acid group in the sulfonated polyarylene thus obtained is 0.5 to 3 mg equivalent / g, preferably 0.8 to 2.8 mg equivalent / g. If it is less than 0.5 milliequivalent / g, the proton conductivity will not increase, while if it exceeds 3 milliequivalent / g, the hydrophilicity will be improved to become a water-soluble polymer, or it will be durable even if it does not become water-soluble. Sex decreases.

The molecular weight of the polymer of the precursor thus obtained before sulfonation of the sulfonic acid group-containing copolymer is 10,000 to 1 in terms of polystyrene weight average molecular weight.
It is, 000,000, preferably 20,000 to 800,000. If it is less than 10,000, the coating film properties are insufficient, such as cracks in the molded film, and there is a problem in strength properties. on the other hand,
If it exceeds 1,000,000, there are problems such as insufficient solubility, high solution viscosity, and poor processability.

(Process for Producing Laminate) In the present invention, the electrode layer is coated with a proton conductive polymer solution or dispersion having a water content of 25 to 50% by weight (hereinafter also referred to as “first varnish”). Then, it is dried to form a thin film composed of the proton conductive polymer, and then a water content of 2 is formed on the thin film.
A laminate containing an electrode layer and an electrolyte layer is manufactured by applying a proton conductive polymer solution or dispersion (hereinafter also referred to as "second varnish") of less than 5% by weight and drying.

The first varnish applied on the electrode layer has a water content of 25 to 45% by weight, preferably 25 to 40% by weight.
The content of the proton conductive polymer is 1 to 10% by weight, preferably 1 to 8% by weight, and the content of the organic solvent is 50 to 70% by weight. As the organic solvent, tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, etc., preferably tetrahydrofuran, N, N -Dimethylformamide, N, N
-Dimethylacetamide, N-methyl-2-pyrrolidone and the like can be mentioned.

Here, the water content in the first varnish was 25.
If the amount is less than 50% by weight, the effect of suppressing the phenomenon that the second varnish applied later is soaked into the electrode layer is low. On the other hand, if the amount exceeds 50% by weight, the sulfonated polyarylene is not uniformly dissolved or dispersed, resulting in a uniform coating. It becomes difficult to form a film. Examples of the method of applying the first varnish on the electrode layer include a bar coating method and a spray method, and the spray method is preferable.

After applying the first varnish on the electrode layer, 50
Dry at ˜150 ° C., preferably 60˜130 ° C. The thickness of the thin film obtained from the first varnish is usually 0.1-10.
μm, preferably 0.2 to 8 μm. Next, the second varnish is applied onto the thin film obtained from the first varnish.

The second varnish has a water content of less than 25% by weight, preferably 10 to 20% by weight, a proton conductive polymer content of 3 to 50% by weight, preferably 5 to 30% by weight, and an organic solvent. The content is 60 to 85% by weight, preferably 65 to 80% by weight. The difference between the water content (wt%) of the first varnish and the water content (wt%) of the second varnish is preferably 5 wt% or more.

Here, the same organic solvent as that used in the first varnish can be used. Second
In the varnish, if the water content is 25% by weight or more,
The concentration of the sulfonated polyarylene in the varnish cannot be sufficiently increased, and a good electrolyte layer cannot be formed.

The second varnish can be applied by a bar coater or a doctor blade method. Usually 50 to 180 after coating
Dry at ℃, preferably 80-150 ℃. The thickness of the thin film obtained from the second varnish is usually 5 to 200 μm, preferably 10 to 100 μm. In the present invention, a third varnish composition may be further applied after forming a coating film applied with the second varnish composition.

The third varnish composition comprises a sulfonated polymer with an alcohol having a boiling point of 100 ° C. or lower and a boiling point of 100.
It is dissolved in a mixed solvent consisting of an organic solvent C having a temperature higher than 0 ° C. Here, the sulfonated polymer may be the same as the sulfonated polymer used in the production of the varnish composition.

As the alcohol having a boiling point of 100 ° C. or lower,
Methanol, ethanol, propanol, isopropyl alcohol, etc. can be mentioned. Boiling point 100
Examples of the organic solvent C having a temperature above ° C are N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, tetramethylurea, dimethylsulfoxide, hexamethylphosphoric triamide, sulfolane. And so on.

In the present invention, the use ratio of the alcohol having a boiling point of 100 ° C. or less and the organic solvent C having a boiling point of 100 ° C. or more is 5 to 75:95 to 25 in weight ratio (however, the total amount is 10
0). The concentration of sulfonated polymer in this third varnish composition is 1 to 50% by weight, preferably 3 to 30% by weight.

Examples of the method for applying the third varnish composition onto the electrode layer coated with the varnish composition include a bar coating method and a spray method, which are obtained from the third varnish composition. The thickness of the coating film is 1 to 100 μm. The coating film of the third varnish composition is 50 to 200
It can be dried by heating at 50 ° C., preferably 50 to 150 ° C. for 15 minutes to 3 hours, preferably 30 minutes to 2 hours.

[0080]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples. [Preparation of Varnish] (1) Preparation of Varnish A 2,5-Dichloro-4 ′-(4-phenoxy) phenoxybenzophenone (hereinafter also referred to as “2,5-DCPPB”): represented by the following formula (a). Monomer (hereinafter referred to as “olig
Also referred to as "o-BCPAF". ) (Mn = 11200, M
w = 27500) = 97: 3 (mol ratio) of the copolymer (Mn = 50000, Mw = 150,000) sulfonated product (sulfonic acid concentration (hereinafter, also referred to as “IEC”) = 2.10 meq / g) ) 2 g was taken in a 250 ml plastic bottle.

[0081]

[Chemical 15]

30 g of distilled water, 63 g of tetrahydrofuran (hereinafter also referred to as "THF"), N-methyl-
2-Pyrrolidone (hereinafter, also referred to as "NMP") 5 g was added, and the mixture was stirred for 20 hours with a wafer broth to have a viscosity of 58 mP.
A varnish A of a · s (25 ° C.) was obtained. (2) Preparation of Varnish B 2,5-DCPPB: oligo-BCPAF (Mn = 112
00, Mw = 27500) = 97: 3 (mol ratio), the copolymer (Mn = 50000, Mw = 15000).
0) sulfonate (IEC = 2.10 meq / g) 2
g was taken in a 250 ml plastic bottle. Distilled water 40
g, methyl ethyl ketone (hereinafter also referred to as “MEK”)
Add 53 g and 5 g of NMP, and add 20 with a wave broth.
The mixture was stirred for a time to obtain a varnish B having a viscosity of 100 mPa · s (25 ° C). (3) Preparation of Varnish C 2,5-DCPPB: oligo-BCPAF (Mn = 112
00, Mw = 27500) = 97: 3 (mol ratio), the copolymer (Mn = 50000, Mw = 15000).
0) sulfonate (IEC = 2.10 meq / g) 2
g was taken in a 250 ml plastic bottle. Distilled water 10
g, THF 63 g, and NMP 25 g were added, and the mixture was stirred for 20 hours with a wave rotor to give a viscosity of 70 mPa · s (25
Varnish C) was obtained. (4) Preparation of Varnish D 250 ml of 4 g of sulfonated tetrafluoroethylene copolymer (trade name: Nafion117, manufactured by DuPont)
I took it in a plastic bottle. Distilled water 15g, methanol 2
Add 0 g, 40 g of isopropyl alcohol, and 21 g of normal propyl alcohol, and add 2 with a wave broth.
The mixture was stirred for 0 hour to obtain a varnish D having a viscosity of 90 mPa · s (25 ° C). (5) Varnish (a) 2,5-DCPPB: oligo-BCPAF (Mn = 112
00, Mw = 27500) = 97: 3 (mol ratio), the copolymer (Mn = 50000, Mw = 15000).
0) sulfonate (IEC = 2.10 meq / g) 1
0 g was taken in a 250 ml plastic bottle. To this, distilled water
20 g, THF 50 g, NMP 20 g were added, and the mixture was stirred for 20 hours with a wafer rotor to give a viscosity of 5290 mPa · s.
A varnish (a) of (25 ° C.) was obtained. (6) Varnish (b) 2,5-DCPPB: oligo-BCPAF (Mn = 11
200, Mw = 27500) = 97: 3 (mol ratio) compositional copolymer (Mn = 50000, Mw = 1500)
00) sulfonate (IEC = 2.10 meq / g)
10 g was taken in a 250 ml plastic bottle. Distilled water (10 g), THF (40 g), and NMP (40 g) were added to this, and the mixture was stirred for 20 hours with a wafer broth to give a viscosity of 5400 mPa
The varnish (b) of s (25 degreeC) was obtained. (7) Varnish (c) 2,5-DCPPB: oligo-BCPAF (Mn = 112
00, Mw = 27500) = 97: 3 (mol ratio), the copolymer (Mn = 50000, Mw = 15000).
0) sulfonate (IEC = 2.10 meq / g) 1
0 g was taken in a 250 ml plastic bottle. In addition to this, NMP
90 g was added, and the mixture was stirred for 20 hours with a wafer rotor to obtain a varnish (c) having a viscosity of 2230 mPa · s (25 ° C.).

[0083]

Example 1 1 mg / cm ² manufactured by Electrochem, USA
Varnish A was spray-coated on the catalyst layer of the platinum-supported gas diffusion electrode using a sprayer. This was heated and dried at 100 ° C. for 30 minutes to form a 0.8 μm thick thin film of the proton conductive sulfonated polymer.

Next, the varnish (a) was coated on the thin film with a coater using a doctor blade. This is 10
The film was heated and dried at 0 ° C. for 1 hour to form a 40 μm-thick film of a proton conductive sulfonated polymer, a laminate was produced, and the following evaluations were performed. The results are shown in Tables 1 and 2. (Observation of Cross Section) A cross section was cut out from the obtained laminate using a microtome. The cross section was observed using a scanning microscope (SEM), and the degree of penetration of the varnish component into the electrode layer was observed.

(Measurement of Total Pore Specific Surface Area) The total pore specific surface area in the electrode layer of the obtained laminate was measured by the mercury porosimetry using an automatic porosimeter. (Fabrication of Fuel Cell and Evaluation of Performance) Two obtained laminates were attached to each other with the surfaces coated with the electrolyte varnish facing each other to produce an electrode membrane assembly. Next, the prepared electrode membrane assembly was sandwiched between two titanium current collectors, and a heater was placed outside the current collectors to assemble a fuel cell having an effective area of 25 cm ² .

The temperature of the fuel cell was kept at 80 ° C., hydrogen was supplied to the fuel electrode at a humidity of 0% RH and oxygen was supplied to the oxidation electrode at a humidity of 65% RH at 2 atm, respectively, and the current density was 1 A / cm ^2. The voltage was measured. Moreover, the change with time of the voltage was observed, and the time until the voltage became 0 V was measured as the power generation possible time.

The results are shown in Table 2.

[0088]

Examples 2 to 3 and Comparative Examples 1 to 4 A laminate was prepared in the same manner as in Example 1 except that each varnish shown in Table 1 was used instead of the varnish A and the varnish (a). The produced laminate was evaluated. The results are shown in Tables 1 and 2.

[0089]

[Table 1]

[0090]

[Table 2]

[0091]

According to the present invention, an electrolyte layer can be formed on an electrode layer without permeation of the electrolyte, and a laminate having good power generation characteristics as an electrode structure can be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nagayuki Kanaoka             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Ryoichiro Takahashi             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Yoichi Asano             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Osamu Sumiya             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. (72) Gen Okiyama             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. F term (reference) 5H026 AA06 CX05 EE18 HH05

Claims (2)

[Claims] 1. A water content of 25 to 50% by weight on the electrode layer.
Apply the proton conductive polymer solution or dispersion of
An electrode layer characterized by being formed by drying to form a thin film comprising the proton conductive polymer, and then applying a solution or dispersion of a proton conductive polymer having a water content of less than 25% by weight to the thin film and drying. A method for producing a laminate comprising an electrolyte layer. 2. The method for producing a laminate according to claim 1, wherein the proton conductive polymer is sulfonated polyarylene.