JP2004149786A - Proton conductor composition and proton conductive membrane - Google Patents

Abstract

An object of the present invention is to provide a proton conductor composition excellent in proton conductivity, water resistance and toughness without increasing the acid concentration of polyarylene having a sulfonic acid group, and a proton conductive membrane comprising the same.
The proton conductor composition comprises a heteropolyacid and a polyarylene having a sulfonic acid group.
[Selection diagram] None

Description

  The present invention relates to a proton conductor composition having improved proton conductivity and a proton conductive membrane comprising the same.

  The electrolyte is often used in a (water) solution. However, in recent years, the tendency to replace this with a solid system has been increasing. The first reason is, for example, the easiness of processing when applied to the above-mentioned electric and electronic materials, and the second reason is the shift to light, thin, short and power saving.

Conventionally, both proton conductive materials and inorganic materials are known. Examples of the inorganic substance include uranyl phosphate, which is a hydrated compound. However, these inorganic compounds have insufficient contact at the interface, and there are many problems in forming a conductive layer on a substrate or an electrode.
On the other hand, examples of the organic compound include a polymer belonging to a so-called cation exchange resin, for example, a sulfonated product of a vinyl polymer such as polystyrene sulfonic acid, a perfluoroalkylsulfonic acid polymer represented by Nafion (trademark, manufactured by DuPont), Organic polymers such as a perfluoroalkyl carboxylic acid polymer and a polymer having a sulfonic acid group or a phosphoric acid group introduced into a heat-resistant polymer such as polybenzimidazole or polyetheretherketone (see Non-Patent Documents 1 to 3). ).

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

  Further, a solid polymer electrolyte comprising a sulfonated rigid polyphenylene has been proposed (see Patent Document 1). This polymer has, as a main component, a polymer obtained by polymerizing an aromatic compound having a phenylene chain (the structure described in column 9 of the same document), and is reacted with a sulfonating agent to introduce a sulfonic acid group. However, although the proton conductivity is improved by increasing the introduction amount of the sulfonic acid group, the mechanical properties of the obtained sulfonated polymer, such as toughness such as elongation at break and bending resistance, and hot water resistance are significantly impaired.

The present inventor studied a composite with a solid acid exhibiting proton conductivity in order to increase the proton conductivity without increasing the acid concentration of the proton conducting membrane. As a result, it has been found that, when a heteropolyacid and a polyarylene having a sulfonic acid group are complexed, proton conductivity can be improved without lowering water resistance and toughness, and the present invention has been completed. Was.
Polymer Preprints, Japan, Vol. 42, No. 7, pp. 2490-2492 (1993) Polymer Preprints, Japan, Vol. 43, No. 3, p. 735-736 (1994) Polymer Preprints, Japan, Vol. 42, No. 3, p. 730 (1993) U.S. Pat. No. 5,403,675

  That is, an object of the present invention is to provide a proton conductor composition having excellent proton conductivity and excellent water resistance and toughness and a proton conductive membrane comprising the same without increasing the acid concentration of polyarylene having a sulfonic acid group. To provide.

According to the present invention, the following proton conductor composition and proton conductive membrane are provided, and the above object of the present invention is achieved.
(1) A proton conductor composition comprising a heteropolyacid and a polyarylene having a sulfonic acid group.
(2) The proton conductor composition according to (1), wherein the heteropolyacid is a heteropolyacid having proton conductivity.
(3) The proton conductor composition according to (1) or (2), wherein the heteropolyacid is contained in a proportion of 1 to 50 parts by weight based on 100 parts by weight of the polyarylene having a sulfonic acid group. .
(4) A proton conductive membrane comprising the proton conductor composition according to any one of (1) to (3).

  According to the present invention, a proton conductor composition having high proton conductivity, for example, a proton conductive membrane can be obtained without increasing the acid concentration of polyarylene having a sulfonic acid group. Further, the proton conductive membrane according to the present invention has excellent resistance to water and excellent toughness.

Hereinafter, the proton conductor fat composition and the proton conductive membrane according to the present invention will be specifically described.
The proton conductor composition according to the present invention comprises a heteropolyacid and a polyarylene having a sulfonic acid group.

(Heteropoly acid)
In the present invention, the heteropolyacid is a compound containing an atom selected from phosphorus, silicon, arsenic, germanium, and boron, and one or two or more atoms selected from tungsten, molybdenum, and vanadium. The compound represented by the following formula can be mentioned.
_{H a M x M 'y O} 40 · nH 2 O
In the formula, M represents an atom selected from P, Si, As, Ge and B, preferably P and Si.
M ′ represents one or more atoms selected from W, Mo and V.
a is a numerical value determined by x and y.
x is an integer of 0 to 12, y is an integer of 0 to 12, and x + y = 13.
n is a positive integer.

  Specific examples of the heteropolyacid include phosphotungstic acid, phosphomolybdic acid, phosphomolybdotungstic acid, phosphomolybdovanadic acid, phosphomolybdenum tungstovanadic acid, catetantenic acid, silicomolybdic acid, silicate molybdenum tungstate, arsenic molybdenum Acids and hydrates thereof can be mentioned.

As the heteropolyacid used in the present invention, a heteropolyacid having proton conductivity is particularly preferable. The term "heteropolyacid having proton conductivity" refers to 10 ^-1 to 10 ^-3 S / cm at room temperature.
Is a compound that shows a high degree of proton conductivity, as the heteropolyacid having such a proton-conducting ability, for example, 12-tungstophosphoric acid, 29-hydrate _{(H 3 PW 12 O 40 ·} 29
H ₂ O) and 12-Moributorin acid 29-hydrate _{(H 3 PMo 12 O 40 ·} 29H 2 O), 12-
Tungstosilicic acid · n hydrate (H ₄ SiW ₁₂ O ₄₀ .nH ₂ O) and the like.

(Polyarylene having sulfonic acid group)
The polyarylene having a sulfonic acid group used in the present invention includes a monomer (A) represented by the following general formula (A) and at least one selected from the following general formulas (B-1) to (B-4). By reacting a polymer obtained by reacting a kind of monomer (B) with a sulfonate, or reacting a monomer (A) with a compound having a sulfonic acid group or an alkylsulfonic acid group in the monomer (B) What is obtained is used.

In the formula (A), R to R ′ may be the same or different from each other, and are a halogen atom excluding a fluorine atom or —OSO ₂ Z (here, Z represents an alkyl group, a fluorine-substituted alkyl group, or an aryl 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.

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

Examples of the fluorine-substituted alkyl group include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group and the like, and a trifluoromethyl group, a pentafluoroethyl group Are preferred.
Examples of the allyl group include a propenyl group,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.

X is a divalent electron-withdrawing group, the electron withdrawing group, e.g. -CO -, - CONH -, - (CF 2) p - ( wherein, p is an integer of 1 to 10), —C (CF ₃ ) ₂ —, —COO—, —SO—, —SO ₂ — and the like.
Note that the electron-withdrawing group means that when the Hammett substituent constant is m-position of the phenyl group,
0.06 or more, in the case of the p-position, a group having a value of 0.01 or more.

  Y represents a divalent electron donating group, and examples of the electron donating group include —O—, —S—, —CH ＝ CH—, —C≡C— and

And the like.
n is 0 or a positive integer, and the upper limit is usually 100, preferably 80.
Specific examples of the monomer represented by the general formula (A) include, for example, 4,4'-dichlorobenzophenone, 4,4'-dichlorobenzanilide, bis (chlorophenyl) difluoromethane, and 2,2-bis (4- Chlorophenyl) hexafluoropropane, 4-chlorobenzoic acid
4-chlorophenyl, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, a compound in which a chlorine atom is replaced by a bromine or iodine atom in these compounds, and a halogen atom substituted in the 4-position in these compounds is And a compound substituted at the 3-position.

Specific examples of the monomer represented by the general formula (A) include, for example, 4,4′-bis (4-chlorobenzoyl) diphenyl ether, 4,4′-bis (4-chlorobenzoylamino) diphenyl ether, 4′-bis (4-chlorophenylsulfonyl) diphenyl ether, 4,4′-bis (4-chlorophenyl) diphenyl ether dicarboxylate, 4,4′-bis [(4-chlorophenyl) -1,1,1,3,3 , 3-hexafluoropropyl]
Diphenyl ether, 4,4'-bis [(4-chlorophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4'-bis [(4-chlorophenyl) tetrafluoroethyl] diphenyl ether A compound in which a chlorine atom is replaced by a bromine atom or an iodine atom in these compounds, a compound in which a halogen atom substituted in the 4-position is substituted in the 3-position in these compounds, and a compound in which a diphenyl ether is substituted in the 4-position in these compounds. Examples include a compound in which at least one of the groups is substituted at the 3-position.

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

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

Usually, the alkali metal is reacted with the hydroxyl group of phenol in an excessive amount, and usually, 1.1 to 2 equivalents are used. Preferably, 1.2 to 1.5 equivalents are used. At this time, a solvent azeotropic with water such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole, and phenetole coexist to form fluorine, chlorine, and the like activated by the electron-withdrawing group. Aromatic dihalide compounds substituted with a halogen atom such as 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-chlorofluorobenzophenone, bis (4-chlorophenyl) sulfone, bis (4 -Fluorophenyl) sulfone, 4-fluorophenyl-4'-chlorophenyl sulfone, 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, preferably 2.2 to 2.8 times, the mole of bisphenol. Before the aromatic nucleophilic substitution reaction, an alkali metal salt of bisphenol may be used in advance. The reaction temperature is between 60C and 300C, preferably between 80C and 250C. Reaction times range 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 different reactivity one by one as an active aromatic dihalide represented by the following formula, since a fluorine atom preferentially causes a nucleophilic substitution reaction with phenoxide. It is convenient for obtaining the desired activated terminal chloro form.

(In the formula, X is as defined for the general formula (A).)
Alternatively, there is a method for synthesizing a flexible compound comprising a target electron-withdrawing group and an electron-donating group by combining a nucleophilic substitution reaction and an electrophilic substitution reaction as described in JP-A-2-159.
Specifically, an aromatic bishalide activated by an electron-withdrawing group, for example, bis (4-chlorophenyl) sulfone is subjected to a nucleophilic substitution reaction with phenol to obtain a bisphenoxy-substituted product. Then, the desired compound is obtained from this substituted product by a Friedel-Crafts reaction with, for example, 4-chlorobenzoic acid chloride. The compounds exemplified above can be applied to the aromatic bishalide activated by the electron-withdrawing group used here. The phenol compound may be substituted, but an unsubstituted compound is preferred from the viewpoint of heat resistance and flexibility. It is preferable to use an alkali metal salt for the phenol substitution reaction. As the usable alkali metal compound, the compounds exemplified above can be used. The amount used is 1.2 to 2 moles per 1 mole of phenol. At the time of the reaction, the above-mentioned polar solvent or the azeotropic solvent with water can be used. The bisphenoxy compound is reacted with chlorobenzoic acid chloride as an acylating agent in the presence of an activator for a Friedel-Crafts reaction of a Lewis acid such as aluminum chloride, boron trifluoride, zinc chloride or the like. Chlorobenzoic acid chloride is used in an amount of 2 to 4 times, preferably 2.2 to 3 times the mole of the bisphenoxy compound. The Friedel-Crafts activator is used in an amount of 1.1 to 2 equivalents per 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 -20C to 80C. As a solvent to be used, chlorobenzene, nitrobenzene, or the like, which is inert to the Friedel-Crafts reaction, can be used.

Further, in the general formula (A), the monomer (A) in which n is 2 or more is, for example, bisphenol which is a supply source of etheric oxygen which is the electron donating group Y in the general formula (A); is a group X,> C = O, -SO 2 -, and / or> C (CF ₃₎ was Kumiawashi and _2, specifically 2,2-bis (4-hydroxyphenyl) -1,1, Alkali metal salts of bisphenols such as 1,3,3,3-hexafluoropropane, 2,2-bis (4-hydroxyphenyl) ketone, 2,2-bis (4-hydroxyphenyl) sulfone and excess 4,4
-Substitution reaction with an active aromatic halogen compound such as dichlorobenzophenone and bis (4-chlorophenyl) sulfone in the presence of a polar solvent such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide and sulfolane Are obtained by sequentially polymerizing according to the synthesis method.

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

In the above, n is 2 or more, preferably 2 to 100, and more preferably 10 to 30.
Next, the monomers represented by formulas (B-1) to (B-4) will be described.

In the formula, R and R ′ may be the same or different from each other, and represent the same groups as R and R ′ in the general formula (A).
R ^{9 to} R ¹⁵ may be the same or different from each other, and include a hydrogen atom, a fluorine atom, an alkyl group,
It represents at least one atom or group selected from the group consisting of a sulfonic acid group and an alkylsulfonic acid group.

Examples of the alkyl group represented by R ^{9 to} R ¹⁵ and the alkyl group contained in the alkylsulfonic acid group include those similar to the alkyl groups represented by R ^{1 to} R ⁸ in formula (A).
m represents 0, 1 or 2.
X represents a divalent electron-withdrawing group selected from the same group as that represented as X in the general formula (A).

Y represents a divalent electron-donating group selected from the same group as that represented as Y in the general formula (A).
W represents at least one group selected from the group consisting of a phenyl group, a naphthyl group and groups represented by the following formulas (C-1) to (C-3).

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

R ^{18 to} R ²⁶ may be the same or different and represent at least one atom or group selected from the group consisting of a hydrogen atom, a fluorine atom and an alkyl group. Examples of the alkyl group represented by R ^{18 to} R ²⁶ include the same alkyl groups represented by R ^{1 to} R ⁸ in formula (A).
q represents 0 or 1.

  Examples of the monomer represented by the general formula (B-1) include a compound represented by the following formula.

  More specifically, the compound represented by the general formula (B-1) includes a compound represented by the following formula.

  In addition, compounds in which a chlorine atom is replaced with a bromine atom or an iodine atom in the above compounds can also be exemplified.

In the formulas (B-2) to (B-4), R and R ′ may be the same or different from each other, and represent the same groups as R and R ′ in the general formula (A).
R ^{27 to} R ³⁴ may be the same or different and are each represented by a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an aryl group, a sulfonic acid group, an alkylsulfonic acid group, or the following general formula (D). Group.

In the formula (D), R ^{35 to} R ⁴³ may be the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, a fluorine-substituted alkyl group, a sulfonic acid group or an alkylsulfonic acid group.
^{R 27 ~R 34, R 35 ~R} 43 is an alkyl group represented as the fluorine-substituted alkyl group, the alkyl group represented by R ¹ to R ^8, include the same groups as fluorine-substituted alkyl group. The aryl groups represented by R ^{27 to} R ³⁴ include the same groups as the aryl groups represented by R ^{1 to} R ⁸ . Examples of the alkyl group contained in the alkylsulfonic acid group represented by R ^{27 to} R ³⁴ and R ^{35 to} R ⁴³ include the same groups as the alkyl group represented by R ^{1 to} R ⁸ .

  X represents a divalent electron-withdrawing group selected from the same group as that represented as X in the general formula (A).

  Y represents a divalent electron-donating group selected from the same group as that represented as Y in the general formula (A).

  Specific examples of the monomer represented by the general formula (B-2) include, for example, p-dichlorobenzene, p-dimethylsulfonyloxybenzene, 2,5-dichlorotoluene, 2,5-dimethylsulfonyloxybenzene, 2,5-dichloro-p-xylene, 2,5-dichlorobenzotrifluoride, 1,4-dichloro-2,3,5,6-tetrafluorobenzene and, in these compounds, a chlorine atom is replaced by a bromine atom or an iodine atom And the like.

Specific examples of the monomer represented by the general formula (B-3) include, for example, 4,4′-dimethylsulfonyloxybiphenyl, 4,4′-dimethylsulfonyloxy-3,3′-dipropenylbiphenyl, 4,4'-dibromobiphenyl, 4,4'-diiodobiphenyl, 4,4'-dimethylsulfonyloxy-3,3'-dimethylbiphenyl, 4,4'-dimethylsulfonyloxy-3,3'- Difluorobiphenyl, 4,4'-dimethylsulfonyloxy-3,3'5,
5′-tetrafluorobiphenyl, 4,4′-dibromooctafluorobiphenyl, 4,4 ′
-Dimethylsulfonyloxyoctafluorobiphenyl and the like.

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

Polyarylene is obtained by reacting the above monomer in the presence of a catalyst.The catalyst used is a catalyst system containing a transition metal compound, and the catalyst system includes (1) a transition metal salt and a coordination A ligand compound (hereinafter, referred to as a “ligand component”) or a transition metal complex (including a copper salt) to which the ligand is coordinated, and (2) a reducing agent as essential components, and "Salts" may be added to increase speed.

  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, iron bromide And iron compounds such as iron iodide; and cobalt compounds such as cobalt chloride, cobalt bromide and cobalt iodide. Of these, nickel chloride and nickel bromide are particularly preferred.

Further, as the ligand component, triphenylphosphine, 2,2′-bipyridine, 1,5-
Cyclooctadiene, 1,3-bis (diphenylphosphino) propane, and the like. Of these, triphenylphosphine and 2,2′-bipyridine are preferred. The compounds as the ligand components can be used alone or in combination of two or more.

Further, as the transition metal complex to which the ligand is coordinated, for example, nickel bis (triphenylphosphine) chloride, nickel bis (triphenylphosphine) bromide, nickel bis (triphenylphosphine) iodide, nickel bis (nitrate) nitrate (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 above catalyst system include iron, zinc, manganese, aluminum, magnesium, sodium, and calcium. Of these, zinc, magnesium and manganese are preferred. These reducing agents can be used more activated by 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, and sodium sulfate, potassium fluoride, potassium chloride, potassium bromide, Potassium compounds such as potassium iodide and potassium sulfate; and 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 usage ratio of each component is usually 0.0001 to 10 mol, preferably 0.01 to 0.5 mol, of the transition metal salt or the transition metal complex per 1 mol of the total of the above monomers. If the amount is less than 0.0001 mol, the polymerization reaction may not proceed sufficiently, while if it exceeds 10 mol, the molecular weight may decrease.
When a transition metal salt and a ligand component are used in the catalyst system, the usage ratio of the ligand component is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. is there. If the amount is less than 0.1 mol, the catalytic activity may be insufficient, while if it exceeds 100 mol, the molecular weight may decrease.

The reducing agent is used in an amount of usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the total amount of the monomers. If the amount is less than 0.1 mol, the polymerization may not proceed sufficiently. If the amount exceeds 100 mol, purification of the obtained polymer may be difficult.
Further, when a "salt" is used, the proportion thereof is usually 0.001 to 100 mol, preferably 0.01 to 1 mol, per 1 mol of the total of the above monomers. If the amount is less than 0.001 mol, the effect of increasing the polymerization rate may be insufficient. If the amount exceeds 100 mol, purification of the obtained polymer may be difficult.

  Examples of the polymerization solvent that can be used include, for example, tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, and the like. Can be Of these, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone are preferred. These polymerization solvents are preferably used after being sufficiently dried.

The total concentration of the above monomers in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40% by weight.
Further, the polymerization temperature at the time of polymerization is usually 0 to 200 ° C, preferably 50 to 120 ° C. Further, the polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

Thus, the monomer (A) represented by the general formula (A) and at least one monomer (B) selected from the monomers represented by the general formulas (B-1) to (B-4) Is polymerized to obtain a polymerization solution containing polyarylene.
Next, a polyarylene having a sulfonic acid group used in the present invention can be obtained by introducing a sulfonic acid group into the above-mentioned polyarylene having no sulfonic acid group by using a sulfonating agent in a conventional manner.

Compounds represented by the above general formulas (B-1) to (B-4) wherein at least one of R ^{9 to} R ¹⁵ or R ^{27 to} R ³⁴ is a sulfonic acid group or an alkylsulfonic acid group. When a polyarylene is produced by using the above, a polyarylene having a sulfonic acid group can be obtained, so that this sulfonation step may not be performed.
As a method for introducing a sulfonic acid group, for example, a polyarylene having no sulfonic acid group can be obtained by using a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, and sodium hydrogen sulfite. (Polymer Preprints, Japan, Vol. 42, No. 3, p. 730 (1993); Polymer Preprints, Japan, Vol. 42, No. 3, p. 736 (1994); Polymer Preprints, Japan, Vol. 42, No. 7, pp. 2490-2492 (1993)].

  That is, as the reaction conditions for this sulfonation, the above-mentioned polyarylene having no sulfonic acid group is reacted with the above-mentioned sulfonating agent in the absence or 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, as well as tetrachloroethane, dichloroethane, chloroform, and chloride. And halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but is generally -50 to 200C, preferably -10 to 100C. The reaction time is usually 0.5 to 1,000 hours, preferably 1 to 200 hours.

In the polyarylene having a sulfonic acid group obtained by sulfonation in this way, R ^{9 to} R ¹⁵ or R ⁹ as a compound represented by the amount of the sulfonic acid group and the general formulas (B-1) to (B-4). ²⁷ at least one amount of sulfonic acid group in the polyarylene having a sulfonic acid group was obtained using the compound such that a sulfonic acid group or an alkyl sulfonic acid group to R ⁴³ is 0.5 to 3 meq / g, preferably 0.8 to 2.8 milligram equivalent / g. If it is less than 0.5 milligram equivalent / g, proton conductivity does not increase, while if it exceeds 3 milligram equivalent / g, hydrophilicity is improved and it becomes a water-soluble polymer, or it is durable even if it does not become water-soluble. Is reduced.

The amount of the sulfonic acid group can be easily adjusted by changing the use ratio of the monomer (A) and the monomer (B), and further changing the type and combination of the monomers.
The molecular weight of the precursor polymer before sulfonation of the sulfonic acid-containing polyarylene thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene equivalent weight average molecular weight.

(Composition)
The proton conductor composition according to the present invention comprises the above-described heteropolyacid and polyarylene having a sulfonic acid.
In the proton conductor composition according to the present invention, the heteropolyacid is 1 to 50 parts by weight, preferably 1 to 40 parts by weight, more preferably 1 to 50 parts by weight, based on the heteropolyacid and 100 parts by weight of the polyarylene having a sulfonic acid. It is contained in a proportion of 30 parts by weight.

  When the content of the heteropolyacid is less than 1 part by weight or more than 50 parts by weight based on 100 parts by weight of the polyarylene having a sulfonic acid, no improvement in proton conductivity is observed. If the amount is less than 1 part by weight, the amount for improving the water retention to increase the proton conductivity may not be reached. If the amount exceeds 50 parts by weight, the water retention is sufficient, but the proton conductivity tends to decrease because the amount of the non-proton conductive component occupying the entire composite membrane increases as the amount added increases.

  The proton conductor composition according to the present invention comprises a heteropolyacid as described above and a polyarylene having a sulfonic acid by a conventionally known method, for example, a high-share mixer such as a homogenizer, a disperser, a paint conditioner, and a ball mill. Can be produced by mixing with the use of In this case, a solvent may be used.

(Proton conductive membrane)
The proton conductive membrane according to the present invention comprises the above-described proton conductor composition.

  The proton conductive membrane according to the present invention contains, in addition to the heteropolyacid and the polyarylene having a sulfonic acid group, sulfuric acid, an inorganic acid such as phosphoric acid, an organic acid containing a carboxylic acid, an appropriate amount of water, and the like. Is also good.

  In order to produce the proton conductive membrane of the present invention, for example, a casting method in which the above-described proton conductor composition is dissolved in a solvent and then formed into a film by casting, a melt molding method, and the like are exemplified.

  Specifically, in the casting method, for example, after dissolving a proton conductor composition in a solvent to form a solution, the solution is cast on a substrate by casting to form a film.

  The substrate is not particularly limited as long as it is a substrate used in a usual solution casting method. For example, a substrate made of plastic or metal is used, and a thermoplastic resin such as polyethylene terephthalate (PET) film is preferably used. A substrate consisting of

  In preparing the proton conductive membrane, an inorganic acid such as sulfuric acid or phosphoric acid, an organic acid containing a carboxylic acid, an appropriate amount of water, or the like may be used in addition to the above-described proton conductor composition.

As the solvent for dissolving the proton conductor composition, for example, N-methyl-2-pyrrolidone,
Non-protonic polar solvents such as N, N-dimethylformamide, γ-butyrolactone, N, N-dimethylacetamide, dimethylsulfoxide, dimethylurea, and the like. Particularly, in view of solubility and solution viscosity, N-methyl-2- Pyrrolidone (hereinafter also referred to as “NMP”) is preferred. The aprotic polar solvent can be used alone or in combination of two or more.

  In addition, a mixture of the aprotic polar solvent and an alcohol can be used as a solvent for dissolving the proton conductor composition. Examples of the alcohol include methanol, ethanol, propyl alcohol, iso-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and the like. In particular, methanol is preferred because it has an effect of lowering the solution viscosity in a wide composition range. Alcohols can be used alone or in combination of two or more.

  When a mixture of an aprotic polar solvent and an alcohol is used as the solvent, the aprotic polar solvent is 95 to 25% by weight, preferably 75 to 25% by weight, and the alcohol is 5 to 75% by weight, preferably 25 to 25% by weight. 75% by weight (however, the total is 100% by weight). When the amount of the alcohol is within the above range, the effect of lowering the solution viscosity is excellent.

  The polymer concentration of the solution in which the proton conductor composition is dissolved depends on the molecular weight of the polyarylene having a sulfonic acid group, but is usually 5 to 40% by weight, preferably 7 to 25% by weight. If the content 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 too high, making it difficult to form a film, and may lack surface smoothness.

The solution viscosity is usually from 2,000 to 100,000 mPa · s, preferably from 3,000 to 50,000 mPa · s, depending on the molecular weight of the polyarylene having a sulfonic acid group and the polymer concentration. If the viscosity is less than 2,000 mPa · s, the retention of the solution during film formation is poor,
It may flow from the substrate. On the other hand, when the viscosity exceeds 100,000 mPa · s, the viscosity is too high and extrusion from a die cannot be performed, and it may be difficult to form a film by a casting method.

  The proton conductive membrane of the present invention can be used as, for example, a proton available for 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 for conductive conductive films.

  The proton conductive membrane according to the present invention has a thickness of usually 10 to 100 μm, preferably 20 to 80 μm.

[Example]
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.
[Measurement of proton conductivity]
The AC resistance was determined by pressing a platinum wire (0.5 mm in diameter) against the surface of a 5 mm-wide strip-shaped film sample, holding the sample in a thermo-hygrostat, and measuring the AC impedance between the platinum wires. The impedance at an alternating current of 10 kHz was measured in an environment of 85 ° C. and a relative humidity of 40%, 50%, 70%, and 90%.

A chemical impedance measuring system manufactured by NF Circuit Design Block Co., Ltd. was used as a resistance measuring device, and JW241 manufactured by Yamato Chemical Co., Ltd. was used as a thermo-hygrostat. Five platinum wires were pressed at 5 mm intervals to change the distance between the electrodes to 5 to 20 mm, and the AC resistance was measured.
The specific resistance of the film was calculated from the distance between the electrodes and the gradient of the resistance according to the following formula, and the AC impedance was calculated from the reciprocal of the specific resistance.

Specific resistance R [Ω · cm] = 0.5 [cm] × film thickness [cm] × resistance gradient [Ω / cm]
[Tensile strength characteristics]
The sulfonated polymer was formed into a film, and a strip-shaped film test piece having a size of 3 mm × 65 mm and a thickness of 50 μm was prepared, and the elastic modulus, the breaking strength and the elongation were measured using a tensile tester.

[Oxidation resistance]
A sulfonated polymer was formed into a film, and a strip-shaped film test piece having a size of 3 mm × 65 mm and a thickness of 50 μm was prepared and immersed in a 3% hydrogen peroxide solution containing 20 ppm of Fe ²⁺ and maintained at 45 ° C. for 20 hours. Was measured for weight change.
Weight retention = (weight of test piece after immersion / weight of test piece before immersion) × 100

2,5-dichloro-4 ′-(4-phenoxy) phenoxybenzophenone (hereinafter referred to as “2.5
-DCPPB ". ): Chlorobenzoylated at both ends [4,4′-dichlorobenzophenone.2,2-bis (4-hydroxyphenyl) -1,1,1,1,3,3,3-hexafluoropropane] condensate (hereinafter “oligo”) -BCPAF ") (Mn = 11,200,
Mw = 27,500) = 97: 3 (molar ratio) copolymer (Mn = 50,000, Mw = 150,000) sulfonate (sulfonic acid concentration (IEC) = 2.10 meq /
g) 60 g was placed in a 1000 ml plastic bottle, and 340 g of N-methyl-2-pyrrolidone was added and dissolved. To this was added 6 g of 12-tungstophosphoric acid / n-hydrate (composite amount of 10 wt%), 900 g of alumina balls were added, mixed with a paint conditioner for 20 minutes, and uniformly dispersed. This solution was filtered through a 200-mesh wire net to remove alumina balls, thereby obtaining a heteropolyacid composite polymer solution.

This solution was coater-coated on a pet film using a doctor blade. This was heated at 80 ° C. for 30 minutes and pre-dried to prepare a membrane, the membrane was peeled off from the pet film, the outer frame of the film was fixed, and the membrane was dried at 150 ° C. for 1 hour. A membrane of a hydrophilic sulfonated polymer was prepared.
The proton conductivity of the produced composite membrane was measured, and the results are summarized in Table 1.

  A film was prepared and evaluated in the same manner as in Example 1 except that the amount of the heteropolyacid used in Example 1 was changed to 3 g (composite amount of 5 wt%). The results are summarized in Table 1.

  A film was prepared and evaluated in the same manner as in Example 1 except that the amount of the heteropolyacid used in Example 1 was changed to 18 g (composite amount of 30 wt%). The results are summarized in Table 1.

  A film was prepared and evaluated in the same manner as in Example 1 except that the amount of the heteropolyacid used in Example 1 was changed to 30 g (composite amount of 50 wt%). The results are summarized in Table 1.

[Comparative Example 1]
Sulfonated product (Mn = 50,000, Mw = 150,000) of a copolymer having a composition ratio of 2,5-DCPPB: oligo-BCPAF = 97: 3 (molar ratio) (sulfonic acid concentration (IEC) = 2. 6.0 g of 10 meq / g) was placed in a 100 ml plastic bottle, and 34 g of NMP was added and dissolved to obtain a polymer solution.
A membrane of a proton-conductive sulfonated polymer was prepared from this polymer solution in the same manner as in Example 1, and the proton conductivity was measured. The results are shown in Table 1.

Claims (4)

  A proton conductor composition comprising a heteropolyacid and a polyarylene having a sulfonic acid group.   The proton conductor composition according to claim 1, wherein the heteropoly acid is a heteropoly acid having proton conductivity.   The proton conductor composition according to claim 1 or 2, wherein the heteropolyacid is contained in an amount of 1 to 50 parts by weight based on 100 parts by weight of the polyarylene having a sulfonic acid group.   A proton conductive membrane comprising the proton conductor composition according to any one of claims 1 to 3.