JP2005246800A - Proton conductive composite film and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proton conductive composite film of a polyarylene having sulfonic acid groups which can improve the strength, toughness and hot water resistance without spoiling proton conductivity, and a method for producing the film. <P>SOLUTION: In the proton conductive composite film, at least two proton conductive films of the polyarylene having sulfonic acid groups are laminated. At least two proton conductive layers are made of the polyarylene having sulfonic acid groups having different ion exchange capacities. In the method for producing the proton conductive composite film, in the production of the proton conductive film described in Claim 1 by laminating the proton conductive film of the polyarylene having at least two sulfonic acid groups, the proton conductive film is made to adhere by using a solution prepared by dissolving the polyarylene having the sulfonic acid groups in an alcoholic solvent or an aprotic solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a proton conductive composite membrane comprising a polyarylene having a sulfonic acid group having proton conductivity, and more specifically, a strength obtained by laminating two or more sulfonated polyarylenes having different ion exchange capacities, The present invention relates to a proton conductive composite membrane excellent in toughness, hot water resistance and proton conductivity.

  The electrolyte is usually used in a (water) solution. However, in recent years, there is an increasing tendency to replace this with a solid system. The first reason is the ease of processing when applied to electrical / electronic materials, and the second reason is the shift to lighter, thinner, smaller and higher power.

  Conventionally, both proton-conducting materials made of inorganic substances and organic substances are known. Examples of inorganic substances include, for example, uranyl phosphate, which is a hydrated compound, but these inorganic compounds do not have sufficient contact at the interface, and there are many problems in forming a conductive layer on a substrate or electrode.

  On the other hand, examples of organic compounds include polymers belonging to so-called cation exchange resins, for example, sulfonated vinyl polymers such as polystyrene sulfonic acid, and perfluoroalkyl sulfonic acid polymers represented by Nafion (registered trademark, manufactured by DuPont). Or organic polymers such as perfluoroalkyl carboxylic acid polymers and polymers in which sulfonic acid groups or phosphoric acid groups are introduced into heat-resistant polymers such as polybenzimidazole and polyether ether ketone (see Non-Patent Documents 1 to 3) Can be mentioned.

  These organic polymers are usually used in the form of a film, but there is an advantage that a conductive film can be bonded on an electrode by utilizing the solubility in a solvent or thermoplasticity. However, many of these organic polymers have not only insufficient proton conductivity, but also have poor durability, a problem that proton conductivity decreases at high temperatures (100 ° C. or higher), and a large dependence on humidity conditions. There is a problem that the adhesiveness with the electrode is not sufficient, a problem that the strength is reduced due to excessive swelling during operation due to the water-containing polymer structure, or the shape is collapsed due to swelling. Therefore, these organic polymers have various problems when applied to the above-mentioned electric / electronic materials.

Patent Document 1 proposes a solid polymer electrolyte made of sulfonated rigid polyphenylene (that is, a sulfonated product having a polyarylene structure as a main component). This polymer is mainly composed of a polymer comprising a phenylene chain obtained by polymerizing an aromatic compound, and this is reacted with a sulfonating agent to introduce a sulfonic acid group. However, although the proton conductivity is improved by increasing the amount of sulfonic acid groups introduced, the mechanical properties of the resulting sulfonated polymer are significantly impaired. Therefore, it is necessary to adjust an appropriate sulfonation concentration that maintains excellent mechanical properties and exhibits proton conductivity. In fact, with this polymer, the sulfonation reaction is likely to proceed, and it is very difficult to control the amount of the appropriate sulfonic acid group introduced, and it is not possible to obtain a polymer with excellent proton conductivity and mechanical properties. It was difficult.
Polymer Preprints, Japan, Vol.42, No.7, p.2490-2492 (1993) Polymer Preprints, Japan, Vol.43, No.3, p.735-736 (1994) Polymer Preprints, Japan, Vol.42, No.3, p.730 (1993) US Pat. No. 5,403,675

  An object of the present invention is to provide a proton conductive composite membrane comprising a polyarylene having a sulfonic acid group that can improve the strength, toughness and hot water resistance of the membrane without impairing the proton conductivity, and a method for producing the same. It is in.

According to the present invention, the following proton conductive composite membrane and a method for producing the same are provided to solve the above-described problems of the present invention.
(1) Two or more proton conducting membranes made of polyarylene having sulfonic acid groups are laminated, and at least two of the two or more proton conducting membranes have sulfonic acid groups having different ion exchange capacities. A proton conductive composite membrane comprising polyarylene.

  (2) The polyarylene having the sulfonic acid group is composed of a repeating unit represented by the following general formula (A) and, if necessary, a repeating unit represented by the following general formula (B). The proton-conductive composite membrane according to (1) above;

(In the formula, Y represents a divalent electron-withdrawing group, Z 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.)

(Wherein R ^{1 to} R ⁸ may be the same as or different from each other, and are at least one 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) W represents a divalent electron-withdrawing group or a single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.)
(3) A first membrane made of polyarylene having a sulfonic acid group having an ion exchange capacity of 0.30 to 4.95 meq / g, and a sulfone having an ion exchange capacity of 0.05 meq / g or more higher than that of the first membrane. The proton conductive composite membrane as described in (1) or (2) above, wherein a second membrane made of polyarylene having an acid group is laminated.

(4) The proton conductive composite membrane as described in (3) above, wherein the polymer used for the first membrane has an ion exchange capacity of 0.60 to 1.80 meq / g.
(5) When the proton conductive membrane made of polyarylene having two or more sulfonic acid groups is laminated to produce the proton conductive composite membrane according to the above (1), the polyarylene having sulfonic acid group is converted into an alcohol solvent. Alternatively, a method for producing a proton conductive composite membrane, comprising adhering the proton conductive membrane using a solution dissolved in an aprotic polar solvent.

  Since the proton conductive composite membrane of the present invention is a laminate of two or more polyarylenes having sulfonic acid groups having different ion exchange capacities, it is possible to combine functions without problems such as peeling of the interface. is there. Therefore, it is possible to improve proton conductivity and hot water resistance without impairing mechanical properties such as strength properties and toughness.

  Therefore, the proton conductive composite membrane of the present invention has high pronton conductivity over a wide temperature range, excellent adhesion to a substrate or an electrode, and also excellent durability, strength, and hot water resistance. It can be used as a conductive membrane such as an electrolyte, an electrolyte for a secondary battery, a solid polymer electrolyte for a fuel cell, a display element, various sensors, a signal transmission medium, a solid capacitor, and an ion exchange membrane.

Hereinafter, the proton conductive composite membrane and the production method thereof according to the present invention will be described in detail.
(Proton conductive composite membrane)
The proton conductive composite membrane according to the present invention comprises two or more proton conductive membranes made of polyarylene having a sulfonic acid group, and at least two of the two or more proton conductive membranes are ion-exchanged with each other. It consists of polyarylene having sulfonic acid groups with different capacities.

  The polyarylene having a sulfonic acid group, which is a component constituting the proton conductive composite membrane, is represented by, for example, a repeating unit represented by the following general formula (A) and, if necessary, the following general formula (B). And polyarylene containing repeating units.

In formula (A), Y represents a divalent electron-withdrawing group, specifically, —CO—, —SO ₂ —, —S
O -, - CONH -, - COO -, - (CF 2) l - (l is an integer of 1 to 10),
-C (CF ₃ ) _2- and the like.

Z represents a divalent electron-donating group or a direct bond, and 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.
A group having a value of 0.06 or more and 0.01 or more in the p-position.
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.
p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
When the polyarylene having a sulfonic acid group includes the repeating structural unit represented by the general formula (A) and the repeating structural unit represented by the general formula (B), specifically, the following general formula It is a polymer represented by (C).

In the formula (C), 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, and Ar, m, n, k, and p and R ¹ to R ⁸ synonymous. x and y represent molar ratios when x + y = 100 mol%.

  The polyarylene having a sulfonic acid group used in the present invention contains 0.5 to 100 mol%, preferably 10 to 99.999 mol% of the repeating unit represented by the formula (A), in the formula (B). Is contained in a proportion of 99.5 to 0 mol%, preferably 90 to 0.001 mol%.

The polyarylene having the sulfonic acid group can be produced by the following method.
(Method for producing polyarylene having a sulfonic acid group)
The polyarylene having the sulfonic acid group includes, for example, a monomer having a sulfonic acid ester group that can be a structural unit represented by the general formula (A), and a structural unit represented by the general formula (B) as necessary. By synthesizing with a possible oligomer to produce a polyarylene having a sulfonic acid ester group, hydrolyzing the polyarylene having the sulfonic acid ester group, and converting the sulfonic acid ester group to a sulfonic acid group can do.

  The polyarylene having a sulfonic acid group is a polyarylene having a structural unit having no sulfonic acid group or sulfonic acid ester group in the general formula (A) and a structural unit of the general formula (B) as necessary. Arylene 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), if necessary. As the monomer that can be the structural unit of the general formula (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 is a halogen atom excluding fluorine (chlorine, bromine, iodine), -OSO ₂ G (
Here, G represents an alkyl group, a fluorine-substituted alkyl group or an aryl group. ), And Y, Z, m, n and k have the same meanings as Y, Z, 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, n-butyl, sec-butyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, cyclopentylmethyl, cyclohexylmethyl, adamantyl, adamantanemethyl, 2-ethylhexyl, 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 , A straight-chain hydrocarbon group such as a bicyclo [2.2.1] heptylmethyl group, a branched hydrocarbon group, an alicyclic hydrocarbon group Such as a hydrocarbon group having 5-membered heterocycles. Among these, 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 neopentyl group is particularly preferable. 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 sulfonate groups —SO ₃ R ^b are substituted, these sulfone groups The acid ester 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, 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 neopentyl group is particularly preferable.

  Specific examples of the sulfonic acid ester represented by the above 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 or cross-linking due to the above, and it is preferable that these ester groups are derived from primary alcohols and the β-position is quaternary carbon.

  Specific examples of the compound having the same skeleton as the sulfonic acid ester represented by the general formula (D) and having no sulfonic acid group and no sulfonic acid ester group include the following compounds.

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

  Examples of the oligomer that can be the structural unit of the general formula (B) include an oligomer represented by the following general formula (E) (hereinafter also referred to as oligomer (E)).

Wherein ^{(E), R 1 ~R 8} , W, T and p are the R ¹ to R ^8, W respectively in the general formula (B), and T and p synonymous.
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 G (wherein G represents an alkyl group, a fluorine-substituted alkyl group or an aryl group). Represents a group. Examples of the alkyl group represented by G 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-chloro). Benzoylamino) 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 chlorine atoms are replaced by bromine atoms or iodine atoms in these compounds Further, in these compounds, compounds in which a halogen atom substituted at the 4-position is substituted at the 3-position, At least one group obtained by substituting at the 4-position of diphenyl ether in these compounds but include compounds substituted at the 3-position.

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 Compound etc. are mentioned.

The compound represented by the general formula (E) can be synthesized, for example, by the method shown below.
First, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenylsulfone, dimethylsulfoxide, etc., in order to convert the bisphenol linked with an electron-withdrawing group to the corresponding alkali metal salt of bisphenol In a polar solvent having a high dielectric constant, an alkali metal such as lithium, sodium or potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate or the like is added.

The alkali metal is reacted in excess with respect to the hydroxyl group of phenol, and is usually used in an amount of 1.1 to 2 times equivalent, preferably 1.2 to 1.5 times equivalent. 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) benzene and the like are reacted. 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).)
Moreover, as a method for synthesizing the compound represented by the general formula (E), a desired electron withdrawing can be performed by combining a nucleophilic substitution reaction and an electrophilic substitution reaction as described in JP-A-2-159. A bendable compound comprising a functional group and an electron donating group may be synthesized.

  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 form a bisphenoxy compound, and then this bisphenoxy compound and 4-chloro The desired compound can be obtained from Friedel-Craft reaction with benzoic acid chloride.

Examples of the aromatic bishalide activated with the electron-withdrawing group used here include the compounds exemplified above. The phenol compound may be substituted, but an unsubstituted compound is preferable from the viewpoint of heat resistance and flexibility. In addition, it is preferable to set it as an alkali metal salt for the substitution reaction of a phenol, and the compound illustrated above is mentioned as an alkali metal compound which can be used. 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.

  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. Further, the Friedel-Crafts reaction between the bisphenoxy compound and the acylating agent chlorobenzoic acid chloride is preferably performed in the presence of a Friedel-Craft activator such as aluminum chloride, boron trifluoride, or zinc chloride. . 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-Craft reaction can be used.

Further, in the general formula (E), the compound in which p is 2 or more is, for example, a bisphenol that is a source of etheric oxygen that 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 excess Substitution reaction with an active aromatic halogen compound such as 4,4-dichlorobenzophenone or bis (4-chlorophenyl) sulfone is carried out with N-methyl-2-pyrrolidone, N, N
-Obtained by sequentially polymerizing the monomer in the presence of a polar solvent such as dimethylacetamide or sulfolane.

  Examples of such compounds include compounds represented by the following formulas.

In the above chemical formula, p is 0 or a positive integer, and the upper limit is usually 100, preferably 1
0-80.
The polyarylene having a sulfonate group represented by the general formula (C) is synthesized by reacting the monomer (D) and, if necessary, the oligomer (E) in the presence of a catalyst. The catalyst used in this case is a catalyst system containing a transition metal compound. As this catalyst system, (1) a compound that becomes a transition metal salt and a ligand (hereinafter referred to as “ligand component”), Alternatively, a transition metal complex coordinated with a ligand (including a copper salt) and (2) a reducing agent may be 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 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 may be used individually by 1 type, and may use 2 or more types together.

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.

  “Salts” 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 0.0001 to 10 mol, preferably 1 to 1 mol of the transition metal salt or transition metal complex, based on 1 mol of the above monomers (total of monomers (D) + oligomer (E), the same applies hereinafter). Is 0.01 to 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 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. . 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 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 1-10 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) is reacted with the oligomer (E) as necessary include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, and N, N-dimethyl. Acetamide, 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.
The polymerization temperature for the polymerization is usually 0 to 200 ° C, preferably 50 to 120 ° C. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

  The polyarylene having a sulfonic acid ester group obtained using the monomer (D) 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. .

As a hydrolysis method,
(1) A method in which polyarylene having a sulfonate group is added to an excess amount of water or alcohol containing a small amount of hydrochloric acid, and the mixture is stirred for 5 minutes or longer. (2) In trifluoroacetic acid, the sulfonate group is added. (3) Method of reacting polyarylene having a temperature of about 80 to 120 ° C. for about 5 to 10 hours (3) 1 to 1 mol of sulfonic acid ester group (—SO ₃ R) in polyarylene having a sulfonic acid ester group A method of adding hydrochloric acid after reacting the polyarylene for about 3 to 10 hours at a temperature of about 80 to 150 ° C. in a solution containing 3 moles of lithium bromide such as N-methylpyrrolidone. Can be mentioned.

  The polyarylene (C) having a sulfonic acid group includes a monomer having a skeleton similar to the sulfonic acid ester represented by the general formula (D) and having no sulfonic acid ester group, and, if necessary, the general formula By synthesizing the oligomer represented by (E), a polyarylene having no sulfonic acid ester group or sulfonic acid group was synthesized in advance, and the polyarylene having no sulfonic acid ester group or sulfonic acid group was sulfonated. Can also be synthesized. That is, after producing a polyarylene having no sulfonic acid group by a method according to the above synthesis method, a sulfonic acid group is introduced into the polyarylene having no sulfonic acid group using a sulfonating agent. Polyarylene (C) having the following can be obtained.

  The method for introducing the sulfonic acid group is not particularly limited, and can be performed by a conventionally known method. For example, the polyarylene having no sulfonic acid group may be prepared by using a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid or sodium hydrogen sulfite in the absence of a solvent or in the presence of a solvent. Sulfonic acid groups can be introduced by sulfonation under conditions [Polymer Preprints, 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)].

Examples of the solvent used in the sulfonation include hydrocarbon solvents such as n-hexane, ether solvents such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide, and dimethylsulfoxide, tetrachloroethane, Halogenated hydrocarbons such as dichloroethane, chloroform, and methylene chloride. Although reaction temperature does not have a restriction | limiting in particular, Usually, -50-200 degreeC, Preferably it is -10-100 degreeC. The reaction time is usually 0.5 to 1,000 hours, preferably 1 to 20 hours.
0 hours.

  The sulfonic acid equivalent in the polyarylene (C) having a sulfonic acid group produced by the method as described above is preferably 0.3 to 5 meq / g. When the sulfonic acid equivalent exceeds 5 meq / g, the water resistance is greatly reduced, and sufficient water resistance may not be obtained even by the effect of lamination, and if it is less than 0.3 meq / g, However, sufficient proton conductivity cannot be maintained.

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-reduced weight average molecular weight by gel permeation chromatography (GPC).

  In addition, although the proton conductive composite membrane of this invention has the said polymer as a main component, you may add an additive as needed. For example, an anti-aging agent, preferably a hindered phenol compound having a molecular weight of 500 or more may be contained, and the durability as an electrolyte can be further improved by containing the anti-aging agent.

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) propionate] (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-tert-butyl-4-hydroxyphenyl) propionate] (
Product name: IRGANOX 1010), 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 1035), octadecyl-3- (3 , 5-Di-tert-butyl-4-hydroxyphenyl) propionate) (trade name: IRGANOX 1076), N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide) (Product 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). 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.

(Proton conductive composite membrane)
The proton conductive composite membrane of the present invention comprises two or more proton conductive membranes made of polyarylene having a sulfonic acid group as described above, and at least two of the two or more proton conductive membranes are stacked. It consists of polyarylene having sulfonic acid groups having different ion exchange capacities. When the proton conductive composite membrane is composed of three or more layers, the layers not adjacent to each other may have the same ion exchange capacity of the polyarylene having sulfonic acid groups forming each layer.

  The proton conductive composite membrane may be composed of two or more types of membranes made of polyarylene having sulfonic acid groups having different ion exchange capacities. Therefore, it may be a two-layer composite film in which proton conductive membranes made of polyarylene having sulfonic acid groups having two different ion exchange capacities are laminated, or made of polyarylene having three layers of sulfonic acid groups. A sandwich structure in which proton conductive membranes are stacked and the ion exchange capacity is different between the intermediate layer and the upper and lower layers may be used. Further, two types are arranged side by side on one surface of the proton conductive membrane made of polyarylene having a sulfonic acid group. The proton conductive membranes made of polyarylene having sulfonic acid groups having different ion exchange capacities as described above may be laminated.

  In the present invention, a membrane (first membrane) made of polyarylene having a sulfonic acid group having an ion exchange capacity of 0.30 to 4.95 meq / g, preferably 0.60 to 1.80 meq / g; , A membrane (second membrane) made of polyarylene having a sulfonic acid group having an ion exchange capacity of 0.05 meq / g or more higher than that of the first membrane, particularly 0.3 to 1. One of the preferred embodiments is a laminate of a film (second film) made of polyarylene having a sulfonic acid group having a high 5 meq / g.

  When the proton conductive composite membrane is formed from two layers, the ion exchange capacity of the polyarylene having a sulfonic acid group forming the first membrane is usually 0.30 to 4.95 meq / g, preferably 0. The ion exchange capacity of the polyarylene having a sulfonic acid group forming the second membrane is usually 0.35, preferably in the range of 0.60 to 3.00 meq / g, particularly preferably 0.60 to 1.80 meq / g. ˜5.00 meq / g, preferably 1.00 to 4.00 meq / g, particularly preferably 1.50 to 3.50 meq / g. If the ion exchange capacity exceeds 5 meq / g in any of the first membrane and the second membrane, the water resistance is significantly lowered, and sufficient water resistance may not be obtained due to the effect of lamination. On the other hand, if either one of the first membrane and the second membrane has an ion exchange capacity of less than 0.3 meq / g, sufficient proton conductivity cannot be maintained due to the effect of lamination.

  The difference between the amount of sulfonic acid groups in the second membrane and the amount of sulfonic acid groups in the first membrane (second membrane-first membrane) is usually 0.05 meq / g or more, preferably 0.1. It is -2.0 meq / g, Most preferably, it is 0.3-1.5 meq / g. If the difference in the amount of sulfonic acid groups between the second membrane and the first membrane is less than 0.05 meq / g, the effect expected from the lamination may not appear.

(Proton conductive membrane manufacturing method)
The membrane composed of the polyarylene having a sulfonic acid group used in the proton conductive composite membrane of the present invention is obtained by dissolving the polyarylene having a sulfonic acid group in an organic solvent to form a homogeneous solution-like polymer composition. Thereafter, a casting method in which the film is cast on a substrate and formed into a film,
It can be produced by a general method such as a method of producing a film by extrusion after mixing and melting polyarylene having a sulfonic acid group.

Examples of the organic solvent used in producing the film by the casting method include N-methyl-2-pyrrolidone, methanol, tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, γ -Butyrolactone, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl Ethyl ether, di Ethylene glycol monobutyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, toluene, xylene, methyl amyl ketone, 4-hydroxy-4-methyl-2-pentanone, ethyl 2-hydroxypropionate, 2-hydroxy-2- Methyl methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3- Examples include methyl ethoxypropionate, ethyl 3-methoxypropionate, methyl lactate, ethyl lactate, chloroform, and methylene chloride. Among these, N-methyl-2-pyrrolidone, methanol, N, N-dimethylformamide, ethyl carbitol, and methyl carbitol are preferable. The organic solvent may be used alone or as a mixed solvent in which two or more kinds are mixed.

  Moreover, the solid content concentration in the polymer composition containing the organic solvent when casting is performed, that is, the ratio of the polymer component is 3 to 40% by weight, preferably 5 to 35% by weight in the polymer composition. . When the amount is less than 3% by weight, a coating film having a sufficient thickness cannot be obtained. On the other hand, when the amount exceeds 40% by weight, casting does not occur sufficiently and a uniform coating film may not be obtained.

Substrates used in the casting method include polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, nylon 6 film, nylon 6,6 film, polypropylene film, plastic film such as polycarbonate film, glass plate, etc. Preferably, a PET film or a glass plate is used.

The thickness of the plastic film (plate) serving as the substrate is usually 50 to 250 μm, preferably 75 to 200 μm. Moreover, in a glass plate, it is 1-5 mm in thickness.
After film formation by the above casting method, the proton conducting membrane of the present invention is obtained by heating and drying at room temperature to 200 ° C., preferably 50 to 150 ° C., for 5 to 180 minutes, preferably 5 to 120 minutes. Drying can be performed under conditions of normal pressure to vacuum. Further, the heating may be performed by sequentially raising the temperature.

The dry film thickness of each film thus obtained is usually 5 to 100 μm, preferably 10 to 80 μm.
(Production method of proton conductive composite membrane)
The proton conductive composite membrane of the present invention can be produced by forming and laminating two or more types of membranes made of polyarylene having sulfonic acid groups having different ion exchange capacities. As a laminating method, after applying the polymer composition as described above on the base material to form the first film, the polymer composition is applied onto the first film to form the second film, A general method such as a method of laminating separately formed proton conductive membranes using a press can be used. In addition, when laminating separately formed films, as an adhesive between the films, an organic solvent used in the production of the above film may be used alone or in combination of two or more kinds, or a sulfone may be added to these organic solvents. You may use what melt | dissolved the polyarylene which has an acid group. Under the present circumstances, the polymer concentration in an adhesive agent is 5-50 weight% normally, Preferably it is 10-30 weight%. In the adhesion method, the adhesive obtained as described above is applied to the bonding surface where the adhesive is laminated, or the film laminated in the adhesive is immersed, and then room temperature to 80 ° C., preferably normal temperature, for 10 to 180 minutes. The film is dried for 10 to 60 minutes, and then the two films are laminated and bonded by heating at 50 to 200 ° C., preferably 50 to 150 ° C. under a pressure of about several hundred g / cm ² . The thickness of the adhesive to be applied is not particularly limited as long as it can be adhered. Moreover, since it is comprised substantially from the same component as a proton conductive film, you may provide an adhesive bond layer as thickness included in the film thickness.
The dry film thickness of the proton conductive composite membrane obtained by laminating in this way is usually 10 to 200 μm, preferably 20 to 100 μm.

In producing the proton conductive composite membrane of the present invention, the film being formed on the substrate or the obtained proton conductive composite membrane may be cured by irradiation with an electron beam. The method of irradiating with an electron beam is not particularly limited, but is preferably performed under the following conditions, for example.
(i) Atmosphere: Nitrogen, argon or vacuum, more preferably under nitrogen atmosphere
(ii) Temperature: 20 to 450 ° C., more preferably room temperature to the glass transition temperature of the polymer component
(iii) Electron dose: 5 to 200 Mrad, more preferably 10 to 150 Mrad
When electron beam irradiation is performed in an atmosphere of nitrogen, argon, or vacuum as described above, the proton conductive membrane is not oxidized, and sufficient heat resistance and durability can be obtained. Although there will be no restriction | limiting in particular if temperature is the range of 20-450 degreeC, If it carries out at the glass transition temperature of a polymer component or several tens of degrees C higher than this, it can harden more efficiently. When the electron dose is in the range of 5 to 200 Mrad, the curing reaction can proceed without causing decomposition of the sulfonated product of polyarylene. If it is less than 5 Mrad, the irradiation energy required for crosslinking may not be obtained, and if it exceeds 200 Mrad, a part of the polymer may be decomposed.

  The proton conductive composite membrane of the present invention is a membrane made of polyarylene having a sulfonic acid group with a large amount of sulfonic acid groups and abundant proton conductivity, and has a low amount of sulfonic acid groups and good strength properties and toughness. Since the film made of polyarylene having a sulfonic acid group is laminated, it is excellent in proton conductivity, strength properties, toughness and hot water resistance.

  Therefore, the composite membrane of the present invention is used for, for example, an electrolyte for a primary battery, an electrolyte for a secondary battery, a polymer solid electrolyte for a fuel cell, a display element, various sensors, a signal transmission medium, a solid capacitor, an ion exchange membrane, and the like. It can be used as a proton conducting membrane.

〔Example〕
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. The sulfonic acid equivalent, molecular weight, proton conductivity, tensile strength, elastic modulus, and hot water resistance were determined as follows.

1. Sulfonic acid equivalent (ion exchange capacity)
The obtained polymer having a sulfonic acid group is washed until the washing water becomes neutral, and the acid remaining free is sufficiently washed with water. After drying, a predetermined amount is weighed, and THF / water Titration was performed using a standard solution of NaOH using phenolphthalein dissolved in a mixed solvent as an indicator, and the sulfonic acid equivalent was determined from the neutralization point.

2. Measurement of Molecular Weight The average molecular weight of polyarylene having no sulfonic acid group was determined by GPC using polystyrene (THF) as a solvent and the molecular weight in terms of polystyrene. The average molecular weight of the polyarylene having a sulfonic acid group was determined by GPC using polystyrene as a molecular weight using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent.

3. Measurement of proton conductivity AC resistance is measured by pressing a platinum wire (φ = 0.5 mm) against the surface of a 5 mm wide strip-shaped proton conducting membrane sample, holding the sample in a thermo-hygrostat, It was obtained from AC impedance measurement. That is, the impedance at an alternating current of 10 kHz was measured in an environment of 25 ° C., 60 ° C., and relative humidity 80%. 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 temperature and humidity control device. Five platinum wires were pressed at intervals of 5 mm, and the AC resistance was measured by changing the distance between the wires to 5 to 20 mm. 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)
4). Tensile strength Tensile strength was measured at room temperature using (No. 2 type test piece of film obtained according to JIS K7127).

5). The elastic modulus was calculated from the initial slope of the stress-strain curve measured in the tensile test.
6). Hot water resistance (dimensional stability)
A proton conductive membrane is cut into 2.0 cm × 3.0 cm and weighed to obtain a test piece for testing. This proton conducting membrane is put into a 250 ml bottle made of polycarbonate, about 100 ml of distilled water is added thereto, and the mixture is heated at 120 ° C. for 24 hours using a pressure cooker tester (PC-242HS made by HIRAYAMA MFS CORP). After completion of the test, each proton conductive membrane was taken out from the hot water, the surface water was gently wiped with a Kimwipe, the dimensions were measured, and the dimensional change rate was measured.

[Example 1]
[Synthesis of first component (a)]
The polyarylene copolymer (a) having a sulfonic acid group used as the first component was synthesized by the following method.

<Preparation of oligomer>
2,2-bis (4-hydroxyphenyl) -1,1,1,3 was added to a 1 L three-necked flask equipped with a stirrer, thermometer, cooling tube, Dean-Stark tube, and three-way cock for introducing nitrogen. , 3,3-hexafluoropropane (bisphenol AF) 67.3 g (0.20 mol), 4,4′-dichlorobenzophenone (4,4′-DCBP) 60.3 g (0.24 mol), potassium carbonate 71 .9 g (0.52 mol), N, N-dimethylacetamide (DMAc) 300 mL, and toluene 150 mL were taken and heated in an oil bath under a nitrogen atmosphere and reacted at 130 ° C. with stirring. When water produced by the reaction was azeotroped with toluene and reacted while being removed from the system with a Dean-Stark tube, almost no water was produced in about 3 hours. Thereafter, most of the toluene was removed while gradually raising the reaction temperature from 130 ° C. to 150 ° C., and the reaction was continued at 150 ° C. for 10 hours. Then, 10.0 g (0.040 mol) of 4,4′-DCBP was added. In addition, the reaction was continued for another 5 hours. The resulting reaction solution was allowed to cool, and then the by-product inorganic compound precipitate was removed by filtration, and the filtrate was put into 4 L of methanol. The precipitated product was separated by filtration, collected, dried, and dissolved in 300 mL of tetrahydrofuran. This was reprecipitated in 4 L of methanol, and the target compound 9
5 g (yield 85%) was obtained.

Number average molecular weight in terms of polystyrene determined by GPC (THF solvent) of the obtained compound (M
n) was 11,200. The obtained compound was soluble in THF, NMP, DMAc, sulfolane and the like, and had a glass transition temperature (Tg) of 110 ° C. and a thermal decomposition temperature of 498 ° C. The obtained compound was an oligomer represented by the formula (I) (hereinafter referred to as “BCPAF oligomer”).

<Preparation of polyarylene copolymer (a) having a sulfonic acid group>
4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonic acid neo was added to a 1 L three-necked flask equipped with a stirrer, thermometer, condenser, Dean-Stark tube, and three-way cock for introducing nitrogen. -Pentyl (A-SO ₃ neo-Pe) 38.94 g (97.04 mmol), BCPAF oligomer (Mw = 11,200) 33.15 g (2.96 mmol), Ni (
PPh ₃ ) ₂ Cl ₂ 1.67 g (2.55 mmol), PPh ₃ 10.49 g (40 mmol), NaI 0.45 g (3 mmol), zinc dust 15.69 g (240 mmol) and dry NMP 390 mL nitrogen Added below. The reaction system is heated with stirring (finally 75
The reaction was allowed to proceed 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 1500 mL of a large excess of methanol to coagulate. The coagulum was collected by filtration, air-dried, redissolved in THF / NMP (200/300 mL each), and coagulated with 1500 mL of a large excess of methanol. After air drying
62.0 g (yield 95%) of a copolymer (PolyAB-SO ₃ neo-Pe) composed of a sulfonic acid derivative protected with a target yellow fibrous neopentyl group was obtained by heat drying. As for the molecular weight by GPC, the number average molecular weight (Mn) was 47,600, and Mw was 159,000.

The copolymer PolyAB-SO ₃ neo-Pe thus obtained (5.1 g) was dissolved in NMP (60 mL) and heated to 90 ° C. A mixture of 50 mL of methanol and 8 mL of concentrated hydrochloric acid was added to the reaction system at one time. While in suspension, the reaction was allowed to proceed for 10 hours under mild reflux conditions. A distillation apparatus was installed, and excess methanol was distilled off to obtain a light green transparent solution. This solution was poured into a large amount of water / methanol (1: 1 weight ratio) to solidify the polymer, and then the polymer was washed with ion-exchanged water until the pH of the washing water became 6 or more. From the IR spectrum of the polymer thus obtained and the quantitative analysis of the ion exchange capacity, it was found that the sulfonic acid ester group (—SO ₃ R ^a ) was quantitatively converted to the sulfonic acid group (—SO ₃ H). .

  The molecular weight of the obtained polyarylene copolymer (a) having a sulfonic acid group by GPC was 53,200 for Mn, 185,000 for Mw, and 1.6 meq / g for sulfonic acid equivalent.

[Synthesis of Second Component (b)]
The polyarylene copolymer (b) having a sulfonic acid group used as the second component is a 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonic acid in the synthesis method of the first component (a). The amount of neo-pentyl (A-SO ₃ neo-Pe) was 39.99 g (99.65 mmol) and the amount of BCPAF oligomer (Mw = 11,200) was 3.92 g (0
. The synthesis was performed in the same manner except that it was changed to 35 mmol). The molecular weight by GPC of the resulting polyarylene copolymer (b) having a sulfonic acid group is as follows: Mn is 54,200, Mw
Was 187,000, and the sulfonic acid equivalent was 3.1 meq / g.

[Production of proton conducting membrane]
The first component (a) and the second component (b) obtained as described above were stirred and mixed at room temperature to a concentration of 10% by weight in N-methylpyrodrin (NMP), respectively. A homogeneous solution was prepared. The resulting solution was a pale yellow transparent solution. The obtained solution composition was cast on a glass substrate using a doctor blade and dried at 80 ° C. for 30 minutes and 150 ° C. for 30 minutes to obtain flexible films (2 types) having a thickness of 20 μm. It was.

Next, a 10% NMP solution of the first component (a) was applied to the upper surface of the film prepared using the first component (a), preliminarily dried at room temperature, and then prepared using the second component (b). The film is stacked on top, using a heat press through a spacer, pre-press for 3 minutes at 100 g / cm ² , and further cured and bonded at 100 ° C. for 30 minutes under a pressure of 1 kg / cm ² to give a film thickness of 40 μm A composite membrane (proton conducting membrane) was obtained. The evaluation results of the obtained proton conductive composite membrane are shown in Table 1.

[Example 2]
[Synthesis of first component (c)]
The polyarylene copolymer (c) having a sulfonic acid group used as the first component is a 4- [4- (2,5-dichlorobenzoyl) phenoxy in the synthesis method of the first component (a) in Example 1 above. The amount of benzene sulfonate neo-pentyl (A-SO ₃ neo-Pe) was 37.72 g (94.00 mmol) and the amount of BCPAF oligomer (Mw = 11,200) was 67.
. The compound was synthesized in the same manner except that the amount was changed to 20 g (6.00 mmol). The obtained polyarylene copolymer (c) having a sulfonic acid group has a molecular weight by GPC of 52, Mn.
400, Mw was 184,000, and the sulfonic acid equivalent was 1.0 meq / g.

[Synthesis of Second Component (d)]
The polyarylene copolymer (d) having a sulfonic acid group used as the second component is a 4- [4- (2,5-dichlorobenzoyl) phenoxy in the synthesis method of the first component (a) of Example 1 above. The amount of neo-pentyl benzenesulfonate (A-SO ₃ neo-Pe) was 39.37 g (98.10 mmol) and the amount of BCPAF oligomer (Mw = 11,200) was 21.
. The compound was synthesized in the same manner except that the amount was changed to 28 g (1.90 mmol). The obtained polyarylene copolymer (d) having a sulfonic acid group has a molecular weight by GPC of 55,
000, Mw was 188,000, and the sulfonic acid equivalent was 2.0 meq / g.

[Production of proton conducting membrane]
The first component (c) and the second component (d) obtained as described above were stirred and mixed at room temperature to a concentration of 10% by weight in N-methylpyrodrin (NMP), respectively. A homogeneous solution was prepared. The resulting solution was a pale yellow transparent solution. The obtained solution composition was cast on a glass substrate using a doctor blade and dried at 80 ° C. for 30 minutes and 150 ° C. for 30 minutes to obtain flexible films (2 types) having a thickness of 20 μm. It was.

Next, a 10% NMP solution of the first component (c) was applied to the upper surface of the film prepared using the first component (c), preliminarily dried at room temperature, and then prepared using the second component (d). The film is stacked on top, using a heat press through a spacer, pre-press for 3 minutes at 100 g / cm ² , and further cured and bonded at 100 ° C. for 30 minutes under a pressure of 1 kg / cm ² to give a film thickness of 40 μm A composite membrane (proton conducting membrane) was obtained. The evaluation results of the obtained proton conductive composite membrane are shown in Table 1.

[Comparative Example 1]
In the synthesis method of the first component (a) of Example 1, the amount of 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonic acid neo-pentyl (A-SO ₃ neo-Pe) 39.66 g (98.82 mmol), BCPAF oligomer (Mw = 11,200)
Was synthesized in the same manner except that the amount of was changed to 13.72 g (1.22 mmol). The obtained polyarylene copolymer (e) having a sulfonic acid group had a molecular weight by GPC of 51,800 for Mn, 183,000 for Mw, and a sulfonic acid equivalent of 2.4 meq / g.

  The copolymer (e) thus obtained was stirred and mixed at room temperature so as to have a concentration of 10% by weight with N-methylpyrodrin to prepare a uniform solution. The resulting solution was a pale yellow transparent solution. The obtained solution composition was cast on a glass substrate using a doctor blade and dried at 80 ° C. for 30 minutes and 150 ° C. for 30 minutes to obtain a flexible film having a thickness of 40 μm. Table 1 shows the evaluation results of the obtained film.

[Comparative Example 2]
In the synthesis method of Comparative Example 1, the amount of 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonate neo-pentyl (A-SO ₃ neo-Pe) was 38.81 g (96.71). Mmol), the amount of BCPAF oligomer (Mw = 11,200) was 36.96.
A polyarylene copolymer (f) was synthesized by the same method except that the amount was changed to g (3.30 mmol), and a film was produced using the copolymer (f).
The molecular weight by GPC of the resulting polyarylene copolymer (f) having a sulfonic acid group was 52,800 for Mn, 185,000 for Mw, and 1.5 meq / g for sulfonic acid equivalent. Table 1 shows the evaluation results of the obtained film.

Claims (5)

  Two or more proton conducting membranes made of polyarylene having a sulfonic acid group are laminated, and at least two of the two or more proton conducting membranes are made of polyarylene having sulfonic acid groups having different ion exchange capacities. A proton conductive composite membrane characterized by comprising: The polyarylene having the sulfonic acid group is composed of a repeating unit represented by the following general formula (A) and, if necessary, a repeating unit represented by the following general formula (B). A proton conducting composite membrane according to claim 1;

(In the formula, Y represents a divalent electron-withdrawing group, Z 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.)

(Wherein R ^{1 to} R ⁸ may be the same as or different from each other, and are at least one 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) W represents a divalent electron-withdrawing group or a single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer).   A first membrane made of polyarylene having a sulfonic acid group having an ion exchange capacity in the range of 0.30 to 4.95 meq / g, and a sulfone having an ion exchange capacity of 0.05 meq / g or more higher than the first membrane; The proton conductive composite membrane according to claim 1 or 2, wherein a second membrane made of polyarylene having an acid group is laminated.   4. The proton conductive composite membrane according to claim 3, wherein an ion exchange capacity of the polymer used for the first membrane is in a range of 0.60 to 1.80 meq / g.   When the proton conductive membrane made of polyarylene having two or more sulfonic acid groups is laminated to produce the proton conductive composite membrane according to claim 1, the polyarylene having sulfonic acid group is converted into an alcohol solvent or aprotic A method for producing a proton conductive composite membrane, comprising adhering the proton conductive membrane using a solution dissolved in a polar solvent.