JP2005171027A - Method of manufacturing proton conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proton conductive film which has a sufficient conductivity of proton even under the condition of a low humidity and a low temperature. <P>SOLUTION: In the manufacturing method of proton conductive film, a composition which contains a polyarylene having sulphonic acid group and an organic solvent performing acid-base mutual action with respect to sulphonic acid group, is cast, and after being dried, the obtained film is immersed in water. It is preferable that the organic solvent to be used has an average dissolution parameter within the range of 9 to 16 (cal/mol)<SP>1/2</SP>, the temperature of the water to be used is within the range of 10 to 100 °C, and the pH is within the range of 1 to 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a proton conducting membrane that can provide a proton conducting membrane suitable for an electrolyte used in a polymer electrolyte fuel cell.

  A fuel cell basically comprises two catalyst electrodes and a solid electrolyte membrane sandwiched between the electrodes. Hydrogen as a fuel is ionized at one electrode, and this hydrogen ion diffuses through the solid electrolyte membrane and then combines with oxygen at the other electrode. At this time, if the two electrodes are connected by an external circuit, a current flows and power is supplied to the external circuit. Here, the solid electrolyte membrane has a function of diffusing hydrogen ions and at the same time physically separating hydrogen and oxygen of the fuel gas and blocking the flow of electrons.

  The morphology of such a solid electrolyte membrane is that nanometer-size hydrophilic channels (ion conduction channels) exist through the membrane, and hydrogen ions diffuse through the water clusters formed in the channels. Yes. Therefore, in an environment of 0 ° C. or lower, there is a problem that ion conductivity is significantly reduced due to freezing of water.

  As a result of studying in view of such problems in the prior art, the present inventor used an organic solvent that interacts with a segment containing a sulfonic acid group and an acid-base interaction as a cast solvent for the polyarylene having a sulfonic acid group. After the cast film is dried, it is immersed in water, and the organic solvent is extracted and removed, increasing the water content of the film and increasing the water content with a freezing point below 0 ° C at the ion conduction site. The inventors have found that a proton conducting membrane having sufficient proton conductivity can be obtained even in an environment of 0 ° C. or lower, and have completed the present invention.

  That is, an object of the present invention is to provide a method for producing a proton conductive membrane having sufficient proton conductivity even at low humidity and low temperature.

According to the present invention, the following polyarylene composition is provided to achieve the object of the present invention.
(1) A polyarylene having a sulfonic acid group and a composition containing an organic solvent that interacts with a sulfonic acid group and acid-base are cast and dried, and then the obtained film is immersed in water. Proton conductive membrane manufacturing method.
(2) The polyarylene having a sulfonic acid group includes a repeating structural unit represented by the following general formula (A) and a repeating structural unit represented by the following general formula (B) (1) ) For producing a proton conducting membrane according to the above;

(In the formula (A), A represents a divalent electron-withdrawing group, B represents a divalent electron-donating group or a direct bond, and Ar represents an aromatic group having a substituent represented by —SO ₃ H. M represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents an integer of 1 to 4.)

(In Formula (B), R ^{1 to} R ⁸ may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. And at least one kind of atom or group, W represents a divalent electron-withdrawing group or single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.) .
(3) The organic solvent that interacts with the sulfonic acid group and acid-base is an organic solvent that contains a nitrogen atom having a substituent, and the nitrogen atom and the substituent are bonded with a single or double bond. The polyarylene composition as described in (1) or (2) above.
(4) The composition further contains an organic solvent that does not interact with a sulfonic acid group and acid-base, an organic solvent that interacts with a sulfonic acid group and acid-base, and an organic solvent that does not interact with a sulfonic acid group and acid-base. The polyarylene composition as described in any one of (1) to (3) above, wherein the average solubility parameter is in the range of 9 to 16 (cal / mol) ^1/2 .
(5) Production of a proton conductive membrane according to any one of (1) to (4), wherein the water has a temperature in the range of 10 to 100 ° C and a pH in the range of 1 to 7. Method.

  According to the present invention, a proton conducting membrane having sufficient proton conductivity can be produced even at low humidity and low temperature.

  The proton conductive membrane produced by the method of the present invention can be used for, for example, an electrolyte for a primary battery, an electrolyte for a secondary battery, a display element, various sensors, a signal transmission medium, a solid capacitor, an ion exchange membrane, and the like.

Hereinafter, the method for producing a proton conductive membrane according to the present invention will be specifically described.
In the method for producing a proton conducting membrane according to the present invention, a composition containing a polyarylene having a sulfonic acid group and an organic solvent that interacts with the sulfonic acid group and acid-base is cast and dried, and then the obtained film is obtained. Immerse in water.

(Polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group used in the present invention includes a repeating structural unit represented by the following general formula (A) and a repeating structural unit represented by the following general formula (B). Polyarylene having
The polyarylene having a sulfonic acid group used in the present invention is represented by a segment (A) containing a sulfonic acid group composed of a repeating structural unit represented by the following general formula (A) and the following general formula (B). It is preferably a block copolymer composed of a segment (B) containing a repeating structural unit and not containing a sulfonic acid group, wherein the segment (A) and the segment (B) are covalently bonded.

In the formula, A represents a divalent electron-withdrawing group, specifically, —CO—, —SO ₂ —, —SO—,
—CONH—, —COO—, — (CF ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CF ₃ ) ₂ — and the like can be mentioned. B represents a divalent electron-donating group or a direct bond. Specific examples of the electron-donating group include — (CH ₂ ) —, —C (CH ₃ ) ₂ —, —O—, —S—, —CH═.
CH-, -C≡C- and

Etc.
The electron-withdrawing group is a Hammett substituent constant when the phenyl group is in the m-position.
In the case of 0.06 or more and p-position, it means a group having a value of 0.01 or more.
Ar represents an aromatic group having a substituent represented by —SO ₃ H, and specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthyl group. Of these groups, a phenyl group and a naphthyl group are preferable.
m represents an integer of 0 to 10, preferably 0 to 2, n represents an integer of 0 to 10, preferably 0 to 2, and k represents an integer of 1 to 4.

In formula (B), R ^{1 to} R ⁸ may be the same as or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. At least one atom or group is shown.
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 trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, trifluoromethyl group, pentafluoroethyl group, and the like. Etc. are preferable.
Examples of allyl groups include propenyl groups,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.

W represents a single bond or a divalent electron-withdrawing group. Examples of the divalent electron withdrawing group include the same ones as described above.
T represents a single bond or a divalent organic group. Specific examples of the divalent organic group include an electron-withdrawing group and an electron-donating group, and examples of the electron-withdrawing group and the electron-donating group include those described above.
In the formula (B), p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.

  Specifically, the polyarylene having a sulfonic acid group is a polymer represented by the following general formula (C).

(In the formula (D), W, T, A, B, Ar, m, n, k, p and R ^{1 to} R ⁸ are respectively W, T, A in the general formulas (A) and (B). , B, Ar, m, n, k, p, and R ^{1 to} R ⁸ .
The polyarylene having a sulfonic acid group used in the present invention contains the repeating structural unit represented by the formula (A) in a proportion of 0.5 to 99.999 mol%, preferably 10 to 99.999 mol%. The repeating structural unit represented by (B) is contained in an amount of 99.5 to 0.001 mol%, preferably 90 to 0.001 mol%.

(Method for producing polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group includes a monomer having a sulfonic acid ester group that can be a structural unit represented by the general formula (A) and an oligomer that can be a structural unit represented by the general formula (B). It can be synthesized by polymerizing to produce a polyarylene having a sulfonic acid ester group, hydrolyzing the polyarylene having a sulfonic acid ester group, and converting the sulfonic acid ester group into a sulfonic acid group.

  The polymer having a sulfonic acid group includes a structural unit having a skeleton represented by the general formula (A) and not having a sulfonic acid group or a sulfonic acid ester group, and a structural unit of the general formula (B). The polyarylene can be synthesized in advance and the polymer can be synthesized by sulfonation.

In the case of synthesizing a polyarylene having a sulfonate group by copolymerizing a monomer that can be a structural unit of the general formula (A) and an oligomer that can be a structural unit of the general formula (B), As a monomer that can be a structural unit of (A), for example, a sulfonate ester represented by the following general formula (D) (hereinafter also referred to as “monomer (D)”) is used.

In the formula (D), X represents a halogen atom other than fluorine (chlorine, bromine, iodine), —OSO ₂ Z (
Here, Z represents an alkyl group, a fluorine-substituted alkyl group or an aryl group. A, B, m, n and k have the same meanings as A, B, m, n and k in the general formula (A), respectively. R ^a represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso- Butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantyl group, adamantanemethyl group, 2-ethylhexyl group, bicyclo [2.2 .1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl group, 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl group , Straight chain hydrocarbon groups such as bicyclo [2.2.1] heptylmethyl group, branched hydrocarbon groups, alicyclic carbon groups Examples thereof include a hydrogen group and a hydrocarbon group having a 5-membered heterocyclic ring. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .

Ar ′ represents an aromatic group having a sulfonate group represented by —SO ₃ R ^b , and specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthyl group. Of these groups, a phenyl group and a naphthyl group are preferable.
The sulfonate group —SO ₃ R ^b is substituted with one or more aromatic groups, and when two or more substituents —SO ₃ R ^b are substituted, these sulfonate esters are substituted. The groups may be the same or different from each other.

Here, R ^b represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, and specific examples thereof include the hydrocarbon groups having 1 to 20 carbon atoms. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .
Specific examples of the sulfonic acid ester represented by the formula (D) include the following compounds.

Further, as the sulfonate ester represented by the general formula (D), a compound in which a chlorine atom is replaced with a bromine atom in the above compound, a compound in which —CO— is replaced with —SO ₂ — in the above compound, and chlorine in the above compound atom is replaced by a bromine atom, and -CO- is -SO ₂ - can also be mentioned such compounds replaced.
The R ^b group in the general formula (D) is derived from a primary alcohol, and the β carbon is a tertiary or quaternary carbon, which is excellent in stability during the polymerization process, and produces sulfonic acid by deesterification. It is preferable in that it does not cause polymerization inhibition and cross-linking, and it is preferable that these ester groups are derived from primary alcohols and the β-position is a quaternary carbon.
Specific examples of the compound having the same skeleton as the sulfonate represented by the general formula (D) and having no sulfonic acid group or sulfonic acid ester group include the following compounds.

A compound in which a chlorine atom is replaced with a bromine atom in the above compound, a compound in which —CO— is replaced with —SO ₂ — in the above compound, a chlorine atom is replaced with a bromine atom in the above compound, and —CO— is replaced with —SO ₂ —. Examples include substituted compounds.

  As the oligomer that can be the structural unit of the general formula (B), for example, a compound represented by the following general formula (E) (hereinafter also referred to as “oligomer (E)”) is used.

In the formula (E), R ^{1 to} R ⁸ , W, T and p are respectively R ^{1 to} R ⁸ in the general formula (B),
Synonymous with W, T and p.
R ′ and R ″ may be the same or different from each other, and are represented by a halogen atom excluding a fluorine atom or —OSO ₂ Z (wherein Z represents an alkyl group, a fluorine-substituted alkyl group or an aryl group). Represents a group. 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.

Specifically, as the compound represented by the general formula (E), when p = 0, for example, 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, 2,6-dichlorobenzonitrile, 9,9- Bis (4-hydroxyphenyl) fluorene is mentioned. In these compounds, compounds in which a chlorine atom is replaced with a bromine atom or an iodine atom, and compounds in which at least one of halogen atoms substituted in the 4-position in these compounds are substituted in the 3-position are exemplified.

When p = 1, the specific compound represented by the general formula (E) is, for example, 4,
4′-bis (4-chlorobenzoyl) diphenyl ether, 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) Tetrafluoroethyl] diphenyl ether, compounds in which the chlorine atom is replaced with a bromine atom or iodine atom in these compounds, compounds in which the halogen atom substituted in the 4-position in these compounds is substituted in the 3-position, and further in these compounds, diphenyl ether At least one of the groups substituted in the 4-position is in the 3-position And the like.

Further, the compound represented by the general formula (E) is 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 the following formula Compounds.

The compound represented by the general formula (E) can be synthesized, for example, by the method shown below.
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, dimethylsulfoxide, etc. Add an alkali metal such as lithium, sodium or potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate or the like in a polar solvent having a high rate.

Usually, the alkali metal is reacted in excess with respect to the hydroxyl group of phenol, and usually 1.1 to 2 times equivalent is used. Preferably, 1.2 to 1.5 times equivalent is used. In this case, fluorine, chlorine, etc. activated with an electron-withdrawing group in the presence of azeotropic solvent such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole, phenetole, etc. Aromatic halogen-substituted aromatic dihalide compounds such as 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, deca Fluorobiphenyl, , 5-difluorobenzophenone, 1,3-bis (4-chlorobenzoyl) reacting benzene. In terms of reactivity, a fluorine compound is preferable, but in consideration of the following aromatic coupling reaction, it is necessary to assemble an 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 mol, preferably 2.2 to 2.8 times mol, of bisphenol. Prior to the aromatic nucleophilic substitution reaction, an alkali metal salt of bisphenol may be used. The reaction temperature is 60 ° C to 300 ° C, preferably 80 ° C to 250 ° C. The reaction time ranges from 15 minutes to 100 hours, preferably from 1 hour to 24 hours. The most preferable method is to use a chlorofluoro compound having one halogen atom having a different reactivity as the active aromatic dihalide represented by the following formula, and a nucleophilic substitution reaction with phenoxide occurs preferentially by the fluorine atom. It is convenient to obtain the desired activated terminal chloro form.

(Wherein, W is as defined for general formula (E).)
In addition, as a method for synthesizing the compound represented by the general formula (E), a nucleophilic substitution reaction and an electrophilic substitution reaction are combined as described in JP-A-2-159, and the target electron-withdrawing group is synthesized. There is a method for synthesizing a flexible compound comprising an electron donating group.
Specifically, an aromatic bishalide activated with an electron-withdrawing group, for example, bis (4-chlorophenyl) sulfone is subjected to a nucleophilic substitution reaction with phenol to obtain a bisphenoxy substitution product. Subsequently, the compound of interest is obtained by Friedel-Craft reaction of this bisphenoxy-substituted product with, for example, 4-chlorobenzoic acid chloride. As the aromatic bishalide activated with the electron-withdrawing group used here, the compounds exemplified above can be applied. Although phenol may be substituted, an unsubstituted compound is preferable from the viewpoint of heat resistance and flexibility. In addition, it is preferable to use an alkali metal salt for the phenol substitution reaction, and the compounds exemplified above can be used as the alkali metal compound. The amount used is 1.2 to 2 moles per mole of phenol. In the reaction, the polar solvent described above or an azeotropic solvent with water can be used. In the Friedel-Crafts reaction, the bisphenoxy-substituted product is reacted with chlorobenzoic acid chloride as an acylating agent in the presence of an activator for the Lewis acid Friedel-Crafts reaction such as aluminum chloride, boron trifluoride, and zinc chloride. . Chlorobenzoic acid chloride is used in an amount of 2 to 4 times mol, preferably 2.2 to 3 times mol, of the bisphenoxy compound. The Friedel-Craft activator is used in an amount of 1.1 to 2 times equivalent to 1 mol of an active halide compound such as chlorobenzoic acid as an acylating agent. The reaction time ranges from 15 minutes to 10 hours, and the reaction temperature ranges from -20 ° C to 80 ° C. As the solvent used, chlorobenzene, nitrobenzene and the like which are inert to Friedel-Crafts reaction can be used.

In the general formula (E), the compound in which p is 2 or more is, for example, a bisphenol serving as a source of etheric oxygen which is the electron donating group T in the general formula (E) and an electron withdrawing group W. A compound in combination with at least one group selected from> C═O, —SO ₂ — and> C (CF ₃ ) ₂ , specifically 2,2-bis (4-hydroxyphenyl) -1,1 1,3,3,3-hexafluoropropane, alkali metal salts of bisphenols such as 2,2-bis (4-hydroxyphenyl) ketone, 2,2-bis (4-hydroxyphenyl) sulfone and an excess of 4 Substitution reactions with active aromatic halogen compounds such as 1,4-dichlorobenzophenone and bis (4-chlorophenyl) sulfone can be performed using N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, etc. In the presence of a neutral solvent, it is obtained by sequential polymerization in the monomer synthesis method.
Examples of such compounds include compounds represented by the following formulas.

In the above, p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
The polyarylene having a sulfonate group is synthesized by reacting the monomer (D) and the oligomer (E) in the presence of a catalyst. The catalyst used in this case is a catalyst system containing a transition metal compound. The catalyst system includes (1) a transition metal salt and a compound to be a ligand (hereinafter referred to as “ligand component”), or a transition metal complex in which a ligand is coordinated (a copper salt). And (2) a reducing agent as an essential component, and in order to further increase the polymerization rate, a “salt” may be added.

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

As the ligand component, triphenylphosphine, 2,2′-bipyridine, 1,5-
Examples include cyclooctadiene and 1,3-bis (diphenylphosphino) propane. Of these, triphenylphosphine and 2,2′-bipyridine are preferred. The compound which is the said ligand component can be used individually by 1 type or in combination of 2 or more types.

Furthermore, as the transition metal complex in which the ligand is coordinated, for example, 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 and the like. Of these, nickel chloride bis (triphenylphosphine) and nickel chloride (2,2′-bipyridine) are preferred.

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

  Examples of the “salt” that can be used in the above catalyst system include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, potassium fluoride, potassium chloride, potassium bromide, Examples include potassium compounds such as 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 from 0.0001 to 10 mol, based on 1 mol of the total amount of the above-mentioned monomers (the total amount of monomers (D) + oligomer (E), hereinafter the same)) of the transition metal salt or transition metal complex. Preferably it is 0.01-0.5 mol. When the amount is less than 0.0001 mol, the polymerization reaction may not proceed sufficiently. On the other hand, when the amount exceeds 10 mol, the molecular weight may decrease.

  In the above catalyst system, when a transition metal salt and a ligand component are used, the ratio of the ligand component used is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. It is. When the amount is less than 0.1 mol, the catalytic activity may be insufficient. On the other hand, when the amount exceeds 100 mol, the molecular weight may decrease.

Moreover, the usage-amount of a reducing agent is 0.1-100 normally with respect to 1 mol of total of the said monomer.
Mol, preferably 1 to 10 mol. If the amount is less than 0.1 mol, polymerization may not proceed sufficiently. If the amount exceeds 100 mol, purification of the resulting polymer may be difficult.

  Furthermore, when using "salt", the usage-ratio is 0.001-100 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 0.01-1 mol. 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.

Examples of the polymerization solvent that can be used when the monomer (D) and the oligomer (E) are reacted include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N,
N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N′-dimethylimidazolidinone and the like can be mentioned. Of these, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N, N′-dimethylimidazolidinone are preferable. These polymerization solvents are preferably used after sufficiently dried.

The total concentration of the monomers in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40% by weight.
Moreover, the superposition | polymerization temperature at the time of superposing | polymerizing is 0-200 degreeC normally, Preferably it is 50-120 degreeC. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

  The obtained polyarylene having a sulfonic acid ester group can be converted into a polyarylene having a sulfonic acid group by hydrolyzing the sulfonic acid ester group and converting it to a sulfonic acid group.

Hydrolysis is
(1) A method in which polyarylene having the sulfonic acid ester group is added to an excess amount of water or alcohol containing a small amount of hydrochloric acid and stirred for 5 minutes or longer. (2) The sulfonic acid ester group is contained in trifluoroacetic acid. Method of reacting polyarylene for about 5 to 10 hours at a temperature of about 80 to 120 ° C. (3) 1 to 3 mol per mol of sulfonic acid ester group (—SO ₃ R) in polyarylene having a sulfonic acid ester group Examples include a method of reacting the polyarylene in a solution containing double moles of lithium bromide, such as N-methylpyrrolidone, at a temperature of about 80 to 150 ° C. for about 3 to 10 hours, and then adding hydrochloric acid. Can do.

  The polyarylene having a sulfonic acid group includes a monomer having a skeleton similar to that of the sulfonic acid ester represented by the general formula (D) and an oligomer represented by the general formula (E). When polyarylene having no sulfonic acid group is synthesized in advance by copolymerization and synthesized by sulfonated polyarylene having no sulfonic acid group, the sulfonic acid group is synthesized by a method according to the above synthesis method. A polyarylene having a sulfonic acid group can be obtained by producing a polyarylene having no sulfonic acid and then introducing a sulfonic acid group into the polyarylene having no sulfonic acid group using a sulfonating agent.

The reaction conditions for the sulfonation of the polyarylene having no sulfonic acid group include polyarylene having no sulfonic acid group and a sulfonic acid group in a conventional manner using a sulfonating agent in the absence of a solvent or in the presence of a solvent. Can be obtained by introducing.
As a method for introducing a sulfonic acid group, for example, the polyarylene having no sulfonic acid group is known by using a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, sodium hydrogen sulfite and the like. (Polymer Prepri
nts, Japan, Vol. 42, No. 3, p. 730 (1993); Polymer Preprints, Japan, Vol. 43, No. 3, p. 736 (1994); Polymer Preprints, Japan, Vol. 42, No. 7, p.2490-2492 (1993)].

  That is, as the reaction conditions for the sulfonation, the polyarylene 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, tetrachloroethane, dichloroethane, chloroform, and chloride. And halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but is usually −50 to 200 ° C., preferably −10 to 100 ° C. Moreover, reaction time is 0.5 to 1,000 hours normally, Preferably it is 1 to 200 hours.

In the polyarylene having a sulfonic acid group produced by the method as described above, the amount of the sulfonic acid group is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably 0.8 to 2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and not practical. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered, which is not preferable.
The amount of the sulfonic acid group can be adjusted, for example, by changing the type, usage ratio, and combination of the monomer (D) and the oligomer (E).

  The molecular weight of the polyarylene having a sulfonic acid group thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).

  The polyarylene having a sulfonic acid group may contain an anti-aging agent, preferably a hindered phenol compound having a molecular weight of 500 or more. By containing the anti-aging agent, the durability as an electrolyte is further increased. Can be improved.

Examples of hindered phenol compounds that can be used in the present invention include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) proonate] (trade name: IRGANOX 245), 1,6-hexanediol-bis [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 259)
2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -3,5-triazine (trade name: IRGANOX 565), pentaerythrityl-tetrakis [ 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 1010), 2,2-thio-diethylenebis [3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate] (trade name: IRGANOX 1035), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) (trade name: IRGANOX 1076), N, N-hexa Methylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide) (trade name: IRGAONOX 1098), 1,3,5-trimethyl-2,4,6
-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (trade name: IRGANOX 1330), Tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate ( Product name: IRGANOX 3114) 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4, 8,10-tetraoxaspiro [5.5] undecane (trade name: Sumilizer GA-80).

  In the present invention, the hindered phenol compound is preferably used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the polyarylene having a sulfonic acid group.

(Organic solvent that interacts with sulfonic acid group-containing segments and acid-base interaction)
Examples of the organic solvent that interacts with the sulfonic acid group and acid-base used in the present invention include methylamine (δ 8.86 *), trimethylamine (δ 6.91 *), ethylamine (δ
8.79 *), diethylamine (δ 7.96), triethylamine (δ 7.52 *)
, Propylamine (δ 8.57 *), isopropylamine (δ 8.45 *), dipropylamine (δ 7.79), butylamine (δ8.72 *), isobutylamine (δ 8.47 *), tri Butylamine (δ 7.96 *), pentylamine (δ 8.70 *), tripentylamine (δ 8.07 *), 2-ethylhexylamine (δ 8.50 *), aniline (δ 11.04), N, N-dimethylaniline (δ 9.17 *), N, N-diethylaniline (δ 9.05 *), cyclohexylamine (δ 9.05), pyridine (δ
10.61), lutidine (δ 8.45 *), ethylenediamine (δ 10.91 *), propylenediamine (δ 10.26 *), diethylenetriamine (δ 12.56), formamide (δ 17.8), N , N-dimethylformamide (δ 12.14), acetamide (δ 14.77 *), N-methylacetamide (δ 11.58 *), N, N-dimethylacetamide (δ 11.12), N, N, N ′, N′-tetramethylurea (δ 10.6
0), 2-pyrrolidone (δ 13.88), N-methyl-2-pyrrolidone (δ 11.17), N, N-dimethylimidazolidinone (δ 11.45 *) and the like.

In the above examples, δ indicates the value of the solubility parameter ((cal / mol) ^1/2 ), and the value with “*” after the numerical value is the calculated value of Fedor (RF Fedors, Polym.Eng.Sci 14 [2] 147 (1974)).
These organic solvents that interact with sulfonic acid groups and acid-base can be used in combination of two or more.

  In the present invention, as the solvent, an organic solvent that does not interact with a sulfonic acid group and an acid-base can be used together with the organic solvent that interacts with the sulfonic acid group and an acid-base.

Examples of the organic solvent that does not interact with the sulfonic acid group and acid-base include methanol (δ 14.2
8), ethanol (δ 12.92), 1-propanol (δ 11.07), 2-propanol (δ 11.50), ethylene glycol (δ 16.30), propylene glycol (δ 14.80), tetrahydrofuran (Δ 9.52), anisole (δ 9.38 *), methyl ethyl ketone (δ 9.27), cyclohexanone (δ 9.88), ethyl acetate (δ 9.10), acetic acid-n-butyl (δ 8. 46), γ-butyrolactone (δ 12
. 78), 2-ethoxyethanol (δ 11.47 *), 1-methoxy-2-propanol (δ 11.27 *), dimethyl sulfoxide (δ 12.93), acetonitrile (δ 11.9), toluene (δ 8.91), hexane (δ 7.24) and the like.
These organic solvents that do not interact with sulfonic acid groups and acid-base can be used in combination of two or more.

When an organic solvent that interacts with a sulfonic acid group and acid-base and an organic solvent that does not interact with a sulfonic acid group and acid-base, an average solubility parameter of the solvent in which these are mixed is 9 to 16 (cal / mol). It is preferably in the range of ^1/2 . Furthermore, the average solubility parameter is preferably in the range of 10.0 to 14.0 (cal / mol) ^1/2 .

  In addition, the calculation method of an average solubility parameter is calculated from the following formula.

_{^{δ Ave = δ 1 × A 1}} /100 + δ 2 × A 2/100 + · ... ·· + δ n × A n / 100
(Δ _Ave : average solubility parameter, δ ⁿ : solubility parameter of each solvent, A ⁿ : weight% of each solvent in organic solvent)
When a composition is prepared using such an organic solvent, the composition is cast and dried, and the resulting film is immersed in water, the amount of water having a freezing point below 0 ° C. is increased. Sufficient proton conductivity is expressed in the following environment.

(Film forming)
In order to produce a proton conducting membrane by the method for producing a proton conducting membrane according to the present invention, first, the above-mentioned components are mixed at a predetermined ratio and kneaded by a conventionally known method, whereby a polyarylene having a sulfonic acid group is obtained. And a composition containing an organic solvent that interacts with sulfonic acid groups and acid-base (hereinafter also referred to as “polyarylene composition”), and then cast this polyarylene composition onto a substrate by casting. Examples of the method for producing a film include a casting method for forming a film.

  Here, examples of the substrate include a polyethylene terephthalate (PET) film, but the substrate is not limited thereto, and any material may be used as long as it is a substrate used in a normal solution casting method. Neither plastic nor metal is particularly limited.

  The polymer concentration at this time is usually 5 to 40% by weight, preferably 7 to 25% by weight, although it depends on the molecular weight of the polyarylene having a sulfonic acid group. If it is less than 5% by weight, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.

The solution viscosity of the polyarylene composition is usually 2,000 to 100,000 mPa · s, preferably 3,000 to 50,000 mPa, although it depends on the molecular weight of the polyarylene having a sulfonic acid group and the polymer concentration. -S. If it is less than 2,000 mPa · s, the retention of the solution during processing is poor and it may flow from the substrate. Meanwhile, 100,000 mPa
・ If it exceeds s, the viscosity is too high to be extruded from the die, and it may be difficult to form a film by the casting method.

  After film formation by the above casting method, a film can be obtained by drying at 30 to 160 ° C., preferably 50 to 150 ° C. for 3 to 180 minutes, preferably 5 to 120 minutes. The resulting film is then peeled off from the substrate and immersed in water for 0.5-24 hours, preferably 3-18 hours, and 25-100 ° C., preferably 30-60 ° C., 3-180 minutes, preferably 5 A proton conducting membrane can be obtained by drying for ˜120 minutes. The dry film thickness is usually 10 to 100 μm, preferably 20 to 80 μm.

  In that case, the temperature of the water which immerses the said film is 10-100 degreeC normally, Preferably it is 15-40 degreeC. If it is less than 10 degreeC, the extraction speed | rate of a solvent is too slow, immersion time may become long, and removal of the solvent which remains in a film may become difficult. In addition, when the temperature exceeds 100 ° C., part of the film may be eluted and the film thickness may change. In addition, the swelling is too large, the shrinkage due to drying after immersion is severe, and the surface smoothness may decrease. is there. Furthermore, the pH of the water for immersing the film is usually 1 to 7, preferably 5 to 6. When pH exceeds 7, since it is alkaline, a sulfonic acid forms a salt and the fall of conductivity occurs.

(Morphology)
The morphology of the proton conducting membrane produced by the method of the present invention is preferably such that the segment (A) containing sulfonic acid groups forms an isotropic continuous phase.
Furthermore, it is preferable that the segment (A) containing a sulfonic acid group forms an isotropic continuous phase, and the component (B) not containing a sulfonic acid group forms a structure close to an island phase.

By taking such a form as a morphology, an ion channel composed of a segment (A) containing a sulfonic acid group penetrating the membrane can be ensured uniformly, and an ion channel composed of a segment (A) containing a sulfonic acid group The amount of water that can be constrained increases and the amount of water having a freezing point below 0 ° C. increases, so that sufficient proton conductivity is exhibited in an environment of 0 ° C. or lower.

  In addition, if the segment (A) containing a sulfonic acid group forms an anisotropic continuous phase or does not form a continuous phase, an ion channel composed of the segment (A) containing a sulfonic acid group penetrates the membrane. Therefore, the amount of water that can be bound to the ion channel composed of the segment (A) containing a sulfonic acid group is reduced, and the amount of water having a freezing point below 0 ° C. is reduced. Cannot produce sufficient proton conductivity.

(Moisture content with freezing point below 0 ° C)
The proton conducting membrane produced by the method of the present invention has a water content having a freezing point below 0 ° C., preferably in the range of 5% by weight to 300% by weight, more preferably in the range of 40% by weight to 200% by weight. .
If the amount of water having a freezing point below 0 ° C. is less than the above range, a sufficient amount of water cannot be secured below 0 ° C. and sufficient ionic conductivity may not be exhibited. When the above range is exceeded, the dimensional change of the cast film is large, and there is a possibility of causing peeling from the electrode layer surface, cracking of the electrode layer, etc. during power generation of the fuel cell.

The cast film was immersed in water at 90 ° C. for 30 minutes and sufficiently impregnated with water. Then, the cast film was taken out, and it was −100 at 5 ° C./min in a differential scanning calorimeter (Thermal Analyst 2000; manufactured by DuPont Instruments). The temperature is lowered to ° C and then raised to 200 ° C. From the amount of heat of the melting peak of water having a freezing point below 0 ° C. at that time, the amount of water having a freezing point below 0 ° C. in terms of dry film weight ratio is calculated.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
In the synthesis examples, the sulfonic acid equivalent weight and the molecular weight were determined as follows.

1. Sulfonic acid equivalent The polymer having the sulfonic acid group was washed with water until the water was neutral, thoroughly washed with water except for free remaining acid, dried, weighed a predetermined amount, THF / Phenolphthalein dissolved in a mixed solvent of water was used as an indicator, titration was performed using a standard solution of NaOH, and the sulfonic acid equivalent was determined from the neutralization point.

2. Measurement of molecular weight The polyarylene weight-average molecular weight not containing a sulfonic acid group was determined by GPC using tetrahydrofuran (THF) as a solvent and the molecular weight in terms of polystyrene. The molecular weight of the polyarylene containing a sulfonic acid group was determined by GPC using polystyrene as a solvent, using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as an eluent.

[Synthesis Example 1]
(Preparation of polyarylene copolymer having a neopentyl group as a protecting group (PolyAB-SO ₃ neo-Pe))
4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonic acid neo-pentyl (A-SO ₃ neo-Pe)

126 mL of dry NMP was represented by the formula (I) with 39.52 g (98.50 mmol) of neo-pentyl (A-SO ₃ neo-Pe) 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonate. Oligomer BCPAF oligomer (Mn = 11,200) 17
. 08 g (1.50 mmol), Ni (PPh ₃ ) ₂ Cl ₂ 1.96 g (3.00 mmol), PPh ₃ 10.49 g (40.00 mmol), NaI 0.45 g (3.00 mmol), zinc Powdered 15.69 g (240 mmol) was added to the mixture under nitrogen.

The reaction system was heated with stirring (finally heated to 74 ° C.) and allowed to react for 3 hours. The polymerization reaction solution was diluted with 250 mL of THF, stirred for 30 minutes, filtered using Celite as a filter aid, and the filtrate was poured into a large excess of 1500 mL of methanol to solidify. The coagulum was collected by filtration, air-dried, redissolved in THF / NMP (200/30 mL each), and coagulated with 1500 mL of a large excess of methanol. After air drying, 47.0 g (yield 92%) of a copolymer (PolyAB-SO ₃ neo-Pe) made of a sulfonic acid derivative protected with a target yellow fibrous neopentyl group was obtained by heat drying. The molecular weight by GPC was Mn = 53,700 and Mw = 187,000.

(Conversion of polyarylene having a neopentyl group as a protective group for sulfonic acid (PolyAB-SO ₃ neo-Pe) to polyarylene having a sulfonic acid group (PolyAB-SO ₃ H))
4.09 g of PolyAB-SO ₃ neo-Pe (8 mmol with respect to SO ₃ neo-Pe) was gradually added to 35 mL of trifluoroacetic acid. The viscous solution was warmed to a gentle reflux condition. During the reaction, 5 mL of trifluoroacetic acid was further added. After 2 hours, the polymer had precipitated, but stirring was continued and allowed to react for a total of 4 hours. After the reaction, it was allowed to cool to room temperature. The precipitate was collected by filtration, and the collected filtrate was suspended and stirred in 400 mL of THF and washed. Further, it was collected by filtration and air-dried to obtain a crude product. The crude product was washed twice with water to finally obtain a light brown powdery polymer.
The amount of sulfonic acid groups in the polymer was 2.2 meq / g (2.2 meq / g from the monomer charge mol at the time of polymerization).

5 g of polyarylene having a sulfonic acid group obtained in Synthesis Example 1 and 36.6 g of N, N-dimethylimidazolidinone were added to a 50 cc screw tube, and 2
Stirring was performed for 4 hours to obtain a uniform polymer solution having a viscosity of 5000 cp.

The above solution is cast on a PET film by a bar coder method, dried at 90 ° C. for 40 minutes, 140 ° C. for 40 minutes, and then immersed in water for 4 hours and dried at 50 ° C. for 1 hour. Thus, a uniform and transparent solid electrolyte film A having a thickness of 40 μm was obtained. The internal structure of the film was observed with an HF-100FA transmission electron microscope (hereinafter “TEM”) manufactured by Hitachi, after cutting out an ultrathin section of the film and staining the section with lead nitrate.

  In TEM observation, it was observed that the domain consisting of the segment (A) containing a sulfonic acid group and the domain consisting of the segment (B) containing no sulfonic acid group were isotropically microphase-separated. It was observed that the domain consisting of segment (B) forms a discontinuous phase, and the domain consisting of segment (A) forms a matrix, is connected on the network and is continuous through the membrane.

[Evaluation]
Using film A, the following evaluation was performed. The results are shown in Table 1.
(Measurement of water content with freezing point below 0 ° C)
The solid electrolyte film A was immersed in water at 90 ° C. for 30 minutes and sufficiently impregnated with water, and then taken out in a differential scanning calorimeter (Thermal Analyst 2000; manufactured by DuPont Instruments).
The temperature is lowered to −100 ° C. at 5 ° C./min, and then raised to 200 ° C. From the amount of heat of the melting peak of water having a freezing point below 0 ° C. at that time, the amount of water having a freezing point below 0 ° C. in terms of the Dry film weight ratio is calculated.

(Measurement of proton conductivity)
For AC resistance, a platinum wire (f = 0.5 mm) is pressed against the surface of a strip-shaped solid electrolyte film A sample having a width of 5 mm, the sample is held in a constant temperature and humidity device, and AC impedance measurement between the platinum wires is performed. I asked for it. That is, the impedance at AC 10 kHz was measured in an environment of 85 ° C., 25 ° C., 5 ° C., 0 ° C., −10 ° C., −20 ° C. and 50% relative humidity. A chemical impedance measurement system manufactured by NF Circuit Design Block Co., Ltd. was used as the resistance measurement device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. The specific resistance of the membrane was calculated from the line-to-line distance and the resistance gradient, and the proton conductivity was calculated from the reciprocal of the specific resistance.

  Specific resistance R (Ω · cm) = 0.5 (cm) × film thickness (cm) × resistance-to-resistance gradient (Ω / cm)

5 g of polyarylene having a sulfonic acid group obtained in Synthesis Example 1, 22.0 g of N-methyl-2-pyrrolidone, and 14.7 g of methanol were added to a 50 cc screw tube, and the mixture was stirred for 24 hours with a wafer blower, and the viscosity was 4000 cp. A homogeneous polymer solution was obtained.

  The above solution is cast on a PET film by a bar coder method, dried at 90 ° C. for 40 minutes, 140 ° C. for 40 minutes, and then immersed in water for 4 hours and dried at 50 ° C. for 1 hour. Thus, a uniform and transparent solid electrolyte film B having a thickness of 38 μm was obtained. The internal structure of the film was observed by TEM after cutting out an ultrathin section of the film and staining the section with lead nitrate.

  In TEM observation, it was observed that the domain consisting of the segment (A) containing a sulfonic acid group and the domain consisting of the segment (B) containing no sulfonic acid group were isotropically microphase-separated. It was observed that the domain consisting of segment (A) and the domain consisting of segment (B) formed a co-continuous phase.

[Evaluation]
Evaluation was performed in the same manner as in Example 1 except that the film B was used instead of the film A. The results are shown in Table 1.

[Comparative Example 1]
4 g of the polyarylene having a sulfonic acid group obtained in Synthesis Example 1 and 2.9 g of water, 21.7 g of dimethoxyethane and 4.7 g of 2-propanol were added to a 50 cc screw tube, and the mixture was stirred for 24 hours with a wafer blower. A uniform polymer solution with a viscosity of 11000 cp was obtained.

  The above solution was cast on a PET film by a bar coder method, and dried at 80 ° C. for 30 minutes and 120 ° C. for 60 minutes to obtain a uniform and transparent solid electrolyte film C having a film thickness of 39 μm. The internal structure of the film was observed by TEM after cutting out an ultrathin section of the film and staining the section with lead nitrate.

In TEM observation, it was observed that the domain composed of the polymer segment (A) containing the ion conductive component and the domain composed of the polymer segment (B) not containing the ion conductive component did not undergo microphase separation and were disordered.
In the solid electrolyte film C, it was observed that the membrane collapsed during the moisture content measurement test and the resistance to hot water was poor, and the measurement of proton conductivity was stopped.

[Comparative Example 2]
5 g of polyarylene having a sulfonic acid group obtained in Synthesis Example 1, 7.3 g of N-methyl-2-pyrrolidone, and 29.3 g of hexane were added to a 50 cc screw tube, and the mixture was stirred for 24 hours with a wafer blower. It could not be dissolved.

Claims (5)

  A proton conductive membrane characterized in that a polyarylene having a sulfonic acid group and a composition containing an organic solvent that interacts with the sulfonic acid group and acid-base are cast, dried, and then immersed in water. Manufacturing method. The polyarylene having the sulfonic acid group includes a repeating structural unit represented by the following general formula (A) and a repeating structural unit represented by the following general formula (B). Production method of proton conducting membrane;

(In the formula (A), A represents a divalent electron-withdrawing group, B represents a divalent electron-donating group or a direct bond, and Ar represents an aromatic group having a substituent represented by —SO ₃ H. M represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents an integer of 1 to 4.)

(In Formula (B), R ^{1 to} R ⁸ may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. And at least one kind of atom or group, W represents a divalent electron-withdrawing group or single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.)   The organic solvent capable of acid-base interaction with the sulfonic acid group is an organic solvent containing a nitrogen atom having a substituent, and the nitrogen atom and the substituent are bonded by a single or double bond. The method for producing a proton conducting membrane according to claim 1 or 2. The composition further contains an organic solvent that does not interact with the sulfonic acid group and acid-base, and an average solution of the organic solvent that interacts with the sulfonic acid group and acid-base and the organic solvent that does not interact with the sulfonic acid group and acid-base. The method for producing a proton conducting membrane according to any one of claims 1 to 3, wherein the sex parameter is in the range of 9 to 16 (cal / mol) ^1/2 . 5. The method for producing a proton conductive membrane according to claim 1, wherein the water has a temperature in a range of 10 to 100 ° C. and a pH in a range of 1 to 7.