JP2008069188A - Resin composition and application thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition formable into a film in a simple process and affording a polyelectrolyte film having excellent swelling resistance of the resultant film under high-temperature and high-humidity conditions and high ionic conductivity characteristics. <P>SOLUTION: The resin composition comprising a sulfonic acid group-containing polymer having a molecular structure represented by formula (1) and a polybenzimidazole-based polymer having a molecular structure represented by formula (7) is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition. Specifically, it relates to a resin composition comprising a specific sulfonic acid group-containing polymer and a specific polybenzimidazole polymer. Furthermore, the present invention relates to the use of the resin composition for polymer electrolyte membranes.

  Examples of electrochemical devices that use a polymer solid electrolyte as an ionic conductor instead of a liquid electrolyte include a water electrolyzer and a fuel cell. The polymer membrane used for these must be sufficiently stable chemically, thermally, electrochemically and mechanically with proton conductivity as a cation exchange membrane. For this reason, perfluorocarbon sulfonic acid membranes have been mainly used as those that can be used over a long period of time. However, if the operation is performed at a temperature exceeding 100 ° C., the moisture content of the membrane is drastically lowered, and the membrane is also softened, so that sufficient performance as a fuel cell cannot be exhibited. Further, in a fuel cell using methanol as a fuel, the performance is deteriorated due to methanol permeation in the membrane, and sufficient performance cannot be exhibited. Furthermore, it has been pointed out as a hindrance to the establishment of fuel cell technology that perfluorocarbon sulfonic acid is too expensive as a membrane or adhesive resin even in a fuel cell that operates at about 80 ° C. using hydrogen as a fuel.

  In order to overcome such drawbacks, various polymer electrolyte membranes in which a sulfonic acid group is introduced into an aromatic ring-containing polymer have been studied. For example, it is conceivable to introduce a sulfonic acid group into an aromatic polyazole-based polymer such as polybenzimidazole, which is known as a high heat resistance and high durability polymer, and use it for the above purpose. As such a polymer structure, polybenzimidazole containing sulfonic acid is synthesized from 3,3′-diaminobenzidine and 3,5-dicarboxybenzenesulfonic acid or 2,5-dicarboxybenzenesulfonic acid ( Non-Patent Document 1) has been reported which synthesizes 1,2,4,5-benzenetetramine and 2,5-dicarboxybenzenesulfonic acid as main components (Patent Document 1). However, in these reports, attention has been paid to the solubility and heat resistance of the sulfonic acid-containing polybenzimidazole, but the electrochemical characteristics of the sulfonic acid group have not been considered. In particular, these materials are inferior in terms of achieving both physical properties such as heat resistance, solvent resistance, and mechanical properties and ion conduction properties, and are unsuitable for uses such as polymer electrolyte membranes.

  Further, regarding an aromatic polymer having a phosphonic acid group, which is considered to have better heat resistance than a sulfonic acid group, 4,4 ′-(2,2,2-trifluoro-1- (trifluoromethyl) ethylidene) bis (2 Polybenzoxazole composed of (aminophenol) has been reported (Patent Document 2). However, this polymer is characterized by alcohol solubility, and pays attention to its potential as a composite material due to its good solubility, and is not considered at all as a solid polymer electrolyte for use in fuel cells. That is, this polymer was clearly not suitable for a solid polymer electrolyte for a fuel cell using methanol as a fuel, and also showed only a low value of ionic conductivity.

On the other hand, aromatic polyarylene ether compounds such as aromatic polyarylene ether ketones and aromatic polyarylene ether sulfones have been studied as a polymer skeletal structure that is promising as a polymer solid electrolyte membrane. A sulfonated one of ether sulfone (Non-patent Document 2) and a sulfonated polyether ether ketone (Patent Document 3) have been reported. However, these polymer electrolyte membranes have good ion conductivity, but have a drawback that they cannot be used as an ion conductive membrane due to large swelling of the membrane under high temperature and high humidity conditions. In order to overcome this drawback, these acidic group-containing polymers are blended with a basic polymer to suppress swelling of the electrolyte membrane under high temperature and high humidity by utilizing an acid / base bond between polymer chains. Attempts to do so have been reported (for example, Non-Patent Documents 3 and 4 and Patent Documents 4 and 5). However, in these blend membranes, if the mixing ratio of the basic polymer is increased, the ionic conductivity of the electrolyte membrane is lowered, and precipitation occurs when the acid / base polymer mixed solution is used. The group-containing polymer must be preliminarily made into an amine salt and the like, and there is a drawback that it becomes a complicated manufacturing process such that acid treatment is necessary after film formation. Further, Patent Document 6 and Patent Document 7 have been reported as polymer electrolyte membranes made of a resin composition in which an acidic group-containing polybenzimidazole and an acidic group-containing polymer are improved in film-forming properties. The film characteristics were not satisfactory.
US Pat. No. 5,312,895 US Pat. No. 5,498,784 JP-A-6-93114 International Patent Publication No. WO99-54407 International Patent Publication No. WO99-54389 JP 2003-327825 A JP 2005-139318 A Journal of Polymer Science., Polymer Chemistry, 1977, 15, p. 1309 Journal of Membrane Science, 1993, 83, p. 211 Solid State Ionics, 1999, 125, p. 243 Journal of Applied Polymer Science, 1999, 74, p. 67

  The object of the present invention is a resin that can be molded by a simple film-forming process, can suppress swelling of the film under high temperature and high humidity, and has a particularly excellent characteristic as a polymer electrolyte membrane exhibiting high ion conduction characteristics It is to obtain a composition.

  As a result of intensive studies, the present inventors have obtained a resin composition comprising a polybenzimidazole polymer having a sulfonic acid group and / or a phosphonic acid group on a specific aromatic ring and a specific sulfonic acid group-containing polymer. It has been found that the above purpose is achieved.

（ただし、Ｘは水素又は１価のカチオン種、Ｙはスルホン基又はケトン基、Ａｒ^１は下記化学式（２）である場合か、または化学式（３）および（４）の両方を同時に含む場合かのいずれかを示す。）

（ただし、Ａｒ^１が化学式（２）である場合、Ｚ^１は酸素原子、ｎは２以上の任意の整数を示す。Ａｒ^１が化学式（３）および（４）の両方を同時に含む場合、Ｚ^１は独立して酸素原子又は硫黄原子のいずれかを、Ｚ^２は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。また、Ａｒ^１が化学式（３）および（４）の両方を同時に含む場合は、上記化学式（１）とともに下記化学式（５）および（６）の分子構造を同時に含む。）

（ただし、Ａｒ^２、Ａｒ^３は２価の芳香族結合ユニットを、Ｚ^３、Ｚ^４は独立して酸素原子又は硫黄原子のいずれかを、Ｚ^５は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。

（ただし、Ｒ^１はイミダゾール環を形成できる４価の芳香族結合ユニットを、Ｒ^２は２価の芳香族結合ユニットを表し、Ｒ^１およびＲ^２はいずれも芳香環の単環であっても複数の芳香環の結合体あるいは縮合環であっても良く、安定な置換基を有していても良い。Ｚは、スルホン酸基および／またはホスホン酸基を表し、その一部が塩構造となっていても良い。ｍ^１は１から４の整数を表す。） That is, the present invention is achieved by adopting the following configurations (1) to (15).
(1) A sulfonic acid group-containing polymer having a molecular structure represented by the following chemical formula (1) and having a logarithmic viscosity of 0.1 or more and a molecular structure represented by the following chemical formula (7), wherein the logarithmic viscosity is A resin composition comprising a polybenzimidazole polymer of 0.25 or more in a mass ratio of 99.9: 0.1 to 30:70.

(Where X is hydrogen or a monovalent cation species, Y is a sulfone group or ketone group, and Ar ¹ is the following chemical formula (2), or includes both of the chemical formulas (3) and (4) simultaneously) Indicates one of these.)

(However, if Ar ¹ is a chemical formula (2), when ^{Z 1} is an oxygen atom, n represents simultaneously contain .Ar ¹ showing the arbitrary integer of 2 or more both chemical formula (3) and (4), Z ¹ independently represents either an oxygen atom or a sulfur atom, Z ² represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, Any one of cyclohexyl groups, and when Ar ¹ contains both of the chemical formulas (3) and (4), the chemical formula (1) and the molecular structure of the following chemical formulas (5) and (6) are included at the same time. .)

(However, Ar ² and Ar ³ are divalent aromatic bond units, Z ³ and Z ⁴ are independently oxygen atoms or sulfur atoms, Z ⁵ is an oxygen atom, sulfur atom, and —C (CH _{3) 2} - group shown, one of the cyclohexyl groups - group, -C _{(CF 3) 2} - group, -CH _2.

(However, R ¹ represents a tetravalent aromatic bond unit capable of forming an imidazole ring, R ² represents a divalent aromatic bond unit, and R ¹ and R ² may be monocyclic aromatic rings. It may be a conjugate of a plurality of aromatic rings or a condensed ring, and may have a stable substituent, Z represents a sulfonic acid group and / or a phosphonic acid group, part of which has a salt structure M ¹ represents an integer of 1 to 4.)

（ただし、Ａｒ^４は２価の芳香族結合ユニットを、ｎは２以上の任意の整数を示す。）
（３）スルホン酸基含有ポリマーの分子構造中のＡｒ^２〜Ａｒ^４が、下記化学式（９）〜（１２）で表される分子構造から選ばれる１種以上である第１または２の発明に記載の樹脂組成物。

（４）スルホン酸基含有ポリマーのＺ^２とＺ^５がいずれも硫黄原子である第１〜３の発明のいずれかに記載の樹脂組成物。 (2) The resin composition according to the first invention, wherein the sulfonic acid group-containing polymer further has a molecular structure represented by the following chemical formula (8).

(However, Ar ⁴ represents a divalent aromatic bond unit, and n represents an arbitrary integer of 2 or more.)
(3) In the first or second invention, Ar ^{2 to} Ar ⁴ in the molecular structure of the sulfonic acid group-containing polymer is at least one selected from the molecular structures represented by the following chemical formulas (9) to (12): The resin composition as described.

(4) The resin composition according to any one of the first to third inventions, wherein Z ² and Z ⁵ of the sulfonic acid group-containing polymer are both sulfur atoms.

（ただし、ｎは０以上の整数を表す。）
（７）スルホン酸基含有ポリマーのスルホン酸基含有量が０．３〜５．０ｍｅｑ／ｇの範囲内である第１〜６の発明のいずれかに記載の樹脂組成物。 (5) Any one of the first to fourth inventions in which the molar ratio of the repeating molecular structure represented by the chemical formulas (1), (5), and (6) and the other repeating molecular structures satisfy Formulas 1 to 3. The resin composition as described.
(Formula 1) 0.9 ≦ (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) ≦ 1.0
(Formula 2) 0.05 ≦ (n1 + n2) / (n1 + n2 + n3 + n4) ≦ 0.7
(Formula 3) 0.01 ≦ (n2 + n4) / (n1 + n2 + n3 + n4) ≦ 0.95
(In the above formula, n1 is the mol% of the repeating molecular structure represented by the chemical formula (1) when Ar ¹ is the chemical formula (3), and n2 is the chemical formula (1 when Ar ¹ is the chemical formula (4) (1). N3 represents the mol% of the repeating molecular structure represented by the chemical formula (5), n4 represents the mol% of the repeating molecular structure represented by the chemical formula (6), n5 Represents the mol% of other repeating molecular structures, respectively.)
(6) The sulfonic acid group-containing polymer is a terminal dihydroxy compound represented by the following chemical formula (13), and is composed of a plurality of components different from each other, and the average composition is 1 <n ≦ 10. The resin composition in any one of the 1st-5th invention obtained by using what is in a range as a part of monomer component.

(However, n represents an integer of 0 or more.)
(7) The resin composition according to any one of the first to sixth inventions, wherein the sulfonic acid group content of the sulfonic acid group-containing polymer is in the range of 0.3 to 5.0 meq / g.

（ただし、Ａｒは２価の芳香族結合ユニットを表し、Ｘ^１は−Ｏ−、−ＳＯ_２−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＯＰｈＯ−からなる群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表す。また、ｎ^１（モル比）は、０．２≦ｎ^１≦１．０の式を満たす。ｍ^１は１から４の整数を表す。）
（９）ポリベンズイミダゾール系ポリマーが、下記の化学式（１６）と化学式（１７）で示される分子構造で表される結合ユニットをｎ^２：（１−ｎ^２）のモル比で有する第１〜７の発明のいずれかに記載の樹脂組成物。

（ただし、Ａｒは芳香族結合ユニットを表し、Ｘ^２は−Ｏ−、−ＳＯ_２−、−Ｓ−、−ＣＨ_２−、−ＯＰｈＯ−よりなる群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表す。また、ｎ^２（モル比）は、０．２≦ｎ^２≦１．０の式を満たす。ｍ^１は１から４の整数を表す。）
（１０）ポリベンズイミダゾール系ポリマーが下記の化学式（１８）と化学式（１９）で示される分子構造で表される結合ユニットをｎ^３：（１−ｎ^３）のモル比で有する第１〜７の発明のいずれかに記載の樹脂組成物。

（ただし、Ａｒは芳香族結合ユニットを表し、Ｘ^３は−Ｏ−、−ＳＯ_２−、−Ｓ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＯＰｈＯ−よりなる群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表す。また、ｎ^３（モル比）は、０．１≦ｎ^３≦０．９の式を満たす。ｍ^３およびｍ^４は１から４の整数を表す。）
（１１）スルホン酸基含有ポリマーとポリベンズイミダゾール系ポリマーとの割合が、質量比で９５：５〜７０：３０である第１〜１０の発明のいずれかに記載の樹脂組成物。 (8) First to seventh polybenzimidazole polymers having a bond unit represented by the structure represented by the following chemical formula (14) and chemical formula (15) in a molar ratio of n ¹ : (1-n ¹ ). The resin composition in any one of invention.

(However, Ar represents a divalent aromatic bond unit, and X ¹ consists of —O—, —SO ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, and —OPhO—. at least one element selected from the group, Ph represents a bivalent aromatic bond unit. in addition, ^{n 1} (molar ratio), the .m ¹ satisfying the formula of 0.2 ≦ ^{n 1} ≦ 1.0 Represents an integer from 1 to 4.)
(9) The first to first polybenzimidazole polymers having a bond unit represented by the molecular structure represented by the following chemical formula (16) and chemical formula (17) in a molar ratio of n ² : (1-n ² ). 8. The resin composition according to any one of the seventh invention.

(However, Ar represents an aromatic bond unit, X ² is at least one selected from the group consisting of —O—, —SO ₂ —, —S—, —CH ₂ —, —OPhO—, and Ph is Represents a divalent aromatic bond unit, and n ² (molar ratio) satisfies a formula of 0.2 ≦ n ² ≦ 1.0. M ¹ represents an integer of 1 to 4.
(10) First to seventh polybenzimidazole polymers having a bond unit represented by the molecular structure represented by the following chemical formula (18) and chemical formula (19) in a molar ratio of n ³ : (1-n ³ ) The resin composition according to any one of the inventions.

(However, Ar represents an aromatic bond unit, and X ³ represents —O—, —SO ₂ —, —S—, —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —. , —OPhO—, wherein Ph represents a divalent aromatic bond unit, and n ³ (molar ratio) is a formula of 0.1 ≦ n ³ ≦ 0.9. M ³ and m ⁴ represent an integer of 1 to 4.)
(11) The resin composition according to any one of the first to tenth inventions, wherein the ratio of the sulfonic acid group-containing polymer and the polybenzimidazole polymer is 95: 5 to 70:30 by mass ratio.

(12) An ion conductive membrane comprising the resin composition according to any one of the first to eleventh inventions.
(13) A composite in which the ion conductive membrane according to the twelfth invention and an electrode are joined.
(14) A fuel cell using the composite according to the thirteenth invention as an ion conductive membrane / electrode assembly.
(15) An adhesive containing the resin composition according to any one of the first to eleventh inventions.

The resin composition of the present invention is excellent in miscibility with a solvent and can be easily formed into a film. The resulting film has excellent ion conductivity and dimensional stability under high temperature and high humidity. It is suitable as an ion exchange membrane for fuel cells. In particular, it is possible to obtain a membrane electrode assembly that is excellent in bondability with an electrode and workability when producing an ion exchange membrane electrode assembly and excellent in durability. Furthermore, since the resin composition of the present invention is excellent in solvent solubility, it can also be used as a binder, an adhesive, and the like when producing a joined body of an ion exchange membrane and an electrode.
The resin composition containing the acidic group-containing polybenzimidazole polymer together with the acidic group-containing polymer of the present invention is a novel material exhibiting excellent properties not only in durability but also in workability and ion conductivity. Since it has such excellent properties, the resin composition of the present invention can be suitably used as a material for a solid polymer electrolyte membrane for a fuel cell.

（ただし、Ｘは水素又は１価のカチオン種、Ｙはスルホン基又はケトン基、Ａｒ^１は下記化学式（２）かまたは化学式（３）および（４）の両方を含むかのいずれかを示す。ｎは２以上の任意の整数を示す。）

（ただし、Ａｒ^１が化学式（２）である場合、Ｚ^１は酸素原子、ｎは２以上の任意の整数を示す。Ａｒ^１が化学式（３）および（４）の両方を同時に含む場合、Ｚ^１は独立して酸素原子又は硫黄原子のいずれかを、Ｚ^２は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。また、Ａｒ^１が化学式（３）および（４）の両方を同時に含む場合は、上記化学式（１）とともに下記化学式（５）および（６）の分子構造を同時に含む。）

（ただし、Ａｒ^２、Ａｒ^３は２価の芳香族結合ユニットを、Ｚ^３、Ｚ^４は独立して酸素原子又は硫黄原子のいずれかを、Ｚ^５は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。） Hereinafter, the present invention will be described in detail.
The sulfonic acid group-containing polymer in the present invention contains a structural unit represented by the following chemical structural formula (1).

(However, X represents hydrogen or a monovalent cation species, Y represents a sulfone group or a ketone group, and Ar ¹ represents either the following chemical formula (2) or the chemical formulas (3) and (4). n represents an arbitrary integer of 2 or more.)

(However, if Ar ¹ is a chemical formula (2), when ^{Z 1} is an oxygen atom, n represents simultaneously contain .Ar ¹ showing the arbitrary integer of 2 or more both chemical formula (3) and (4), Z ¹ independently represents either an oxygen atom or a sulfur atom, Z ² represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, Any one of cyclohexyl groups, and when Ar ¹ contains both of the chemical formulas (3) and (4), the chemical formula (1) and the molecular structure of the following chemical formulas (5) and (6) are included at the same time. .)

(However, Ar ² and Ar ³ are divalent aromatic bond units, Z ³ and Z ⁴ are independently oxygen atoms or sulfur atoms, Z ⁵ is an oxygen atom, sulfur atom, and —C (CH _{3) 2} - group, -C _{(CF 3) 2} - group, -CH ₂ - group, any one of a cyclohexyl group).

  In the chemical formula (1), monovalent cation species for X include monovalent metal salts such as sodium and potassium, salts with organic base compounds such as ammonium salts, and the like. The molecular structure of the above chemical formula (1) has 3,3′-disulfo-4,4′-dihalogenated diphenylsulfone, 3,3′-disulfo-4,4′-dihalogenated benzophenone or derivatives thereof and a specific fragrance. It is a structural component formed from an aromatic dihydroxy compound and / or an aromatic dithiol compound by an aromatic nucleophilic substitution reaction. Since the sulfonated polymer in the present invention is characterized by containing the molecular structure of the chemical formula (1) in the polymer chain, it may be composed only of the molecular structure represented by the chemical formula (1). However, it may be in the form of a copolymer obtained by copolymerizing one or more aromatic dihydroxy compounds or aromatic dihalogenated compounds other than those giving the molecular structure of the chemical formula (1). In addition, the molecular structure giving the chemical formula (1) is not limited to one type, and one or more molecular structures may exist, and a plurality of molecular structural components other than the chemical formula (1) may exist. good. In any case, when the molecular structure represented by the chemical formula (1) is present in the sulfonated polyarylene ether, the compound is excellent in ion conductivity, heat resistance, and processability. In the sulfonic acid group-containing polyarylene ether of the present invention, the proportion of the structural unit represented by the molecular structural formula is preferably 10% or more, and more preferably 20% or more.

A preferred molecular structure in the chemical formula (1) is such that Ar ¹ is represented by the chemical formula (2), and 3,3′-disulfo-4,4′-dihalogenated diphenylsulfone, 3,3′-disulfo- It is a molecular structural component formed by aromatic nucleophilic substitution reaction from 4,4′-dihalogenated benzophenone or a derivative thereof and a terminal hydroxyl group-containing phenylene ether oligomer. The portion composed of the phenylene ether oligomer is represented by any number selected from the integers of 2 or more in the above formula. n may be a single compound composed of specific numbers, but may be a mixture of a plurality of n. In addition, as long as it includes a component where n is 2 or more, a diphenyl ether unit or a diphenoxybenzene unit corresponding to n = 0 or n = 1 may be included. In order to effectively contain the amount of sulfonic acid group in the molecular chain, it is preferable that n is mainly selected from 10 or less. In the present invention, since the characteristics of the polyarylene ether molecular chain are increased by including the structure of the above formula (1) in which n is 2 or more, the sulfonic acid group-containing polyarylene ether of the present invention Among them, the proportion of the structural unit represented by the molecular structural formula is preferably 10% or more, and more preferably 20% or more.

As described above, the sulfonic acid group-containing polymer in the present invention includes a molecular structure in which Ar ¹ is represented by the chemical formula (2) in the structural unit represented by the chemical formula (1) in the molecular structure. Therefore, the method for introducing the molecular structure of the chemical formula (1) is not particularly limited. As a general method, 4,4′-dihalogenated benzophenone and / or 4,4′-dihalogenated diphenylsulfone containing a sulfonic acid group or a sulfonic acid group derivative capable of giving the above chemical formula (1) and a terminal hydroxyl group The phenylene ether oligomer can be synthesized by an aromatic nucleophilic substitution reaction using at least a part of the monomer. Specific examples of 4,4′-dihalogenated benzophenone and / or 4,4′-dihalogenated diphenylsulfone containing sulfonic acid groups or sulfonic acid group derivatives include 3,3′-disulfo-4,4′-dichloro Diphenyl sulfone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, 3,3′-disulfo-4,4′-dichlorobenzophenone, 3,3′-disulfo-4,4′-difluorobenzophenone, and Examples thereof include those in which those sulfonic acid groups are converted to salts with monovalent cation species. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto.

ただし、ｎは２以上の整数から選ばれる任意の数で示される。ｎは特定の数字からなる単独化合物でも良いが、複数のｎが混合されたものであっても良い。化学式（２）で表される構成成分はフェニレンエーテルオリゴマーが占める割合が大きいため、本発明におけるスルホン酸基含有ポリマーの分子鎖をより柔軟にするのに有効である。本発明におけるスルホン酸基含有ポリマーが上記化学式（１）および化学式（８）で表される構成成分を含む場合は、本発明におけるスルホン化ポリアリーレンエーテルの全構成単位中にそれらの構成単位が４０％以上含有されていれば好ましく、６０％以上であればさらに好ましい。 Moreover, it is preferable that the sulfonic acid group containing polymer in this invention contains the structural component shown by following Chemical formula (8) with the molecular structure represented by the said Chemical formula (1).

However, n is shown by the arbitrary numbers chosen from an integer greater than or equal to 2. n may be a single compound composed of specific numbers, but may be a mixture of a plurality of n. Since the component represented by the chemical formula (2) has a large proportion of the phenylene ether oligomer, it is effective for making the molecular chain of the sulfonic acid group-containing polymer in the present invention more flexible. When the sulfonic acid group-containing polymer in the present invention contains the constituents represented by the above chemical formulas (1) and (8), the constituent units are 40 in all the constituent units of the sulfonated polyarylene ether in the present invention. % Or more is preferable, and 60% or more is more preferable.

ただし、ｎは２以上の整数から選ばれる任意の数で示される。ｎは特定の数字からなる単独化合物でも良いが、複数のｎが混合されたものであっても良い。化学式（２）で表される構成成分はフェニレンエーテルオリゴマーが占める割合が大きいため、本発明におけるスルホン酸基含有ポリマーの分子鎖をより柔軟にするのに有効である。本発明におけるスルホン酸基含有ポリマーが上記化学式（１）および化学式（２０）で表される構成成分を含む場合は、本発明におけるスルホン酸基含有ポリマーの全構成単位中にそれらの構成単位が４０％以上含有されていれば好ましく、６０％以上であればさらに好ましい。
上記化学式（２０）を与えることができるジハロゲン化化合物の例として、２，６−ジクロロベンゾニトリル、２，６−ジフルオロベンゾニトリル、等を挙げることができる。 In addition, the molecular structure represented by the chemical formula (8) is preferably a constituent component represented by the following chemical formula (20).

However, n is shown by the arbitrary numbers chosen from an integer greater than or equal to 2. n may be a single compound composed of specific numbers, but may be a mixture of a plurality of n. Since the component represented by the chemical formula (2) has a large proportion of the phenylene ether oligomer, it is effective for making the molecular chain of the sulfonic acid group-containing polymer in the present invention more flexible. When the sulfonic acid group-containing polymer in the present invention contains the structural components represented by the chemical formula (1) and the chemical formula (20), those structural units are 40 in all the structural units of the sulfonic acid group-containing polymer in the present invention. % Or more is preferable, and 60% or more is more preferable.
Examples of the dihalogenated compound that can give the chemical formula (20) include 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, and the like.

ただし、ｎは２以上の整数から選ばれる任意の数を示す。化学式（１３）で表される末端ヒドロキシル基含有フェニレンエーテルオリゴマーはｎが単一の化合物からなるものを使用しても良いが、ｎの異なる複数の成分を含んでいても良い。ｎの異なる複数の成分を含んでいる場合には、その平均組成が１＜ｎ≦１０の範囲にあるものをモノマー成分の一部として使用することが好ましい。また、より好ましくは平均組成が２≦ｎ≦１０の範囲にあるものをモノマー成分の一部として使用することが好ましい。平均組成としてのｎが１より小さいと得られるポリマーのガラス転移温度が高くなり、燃料電池用材料としての加工性が低下する傾向にあり、平均組成がｎ＞１０であるとガラス転移温度が低くなり燃料電池材料として使用する際の耐熱性が不十分となる傾向が現れるためである。なお、化学式（１３）で表される末端ヒドロキシル基含有フェニレンエーテルオリゴマーがｎのことなる複数の成分を含んでいる場合、その平均組成はＮＭＲ等により、ｎのことなる成分の存在率はＧＰＣ等により決定することができる。 In the aromatic nucleophilic substitution reaction for obtaining the sulfonic acid group-containing polymer in the present invention, the terminal hydroxyl group-containing phenylene ether oligomer giving the chemical formulas (1) and (8) can be represented by the following chemical formula (13).

However, n shows the arbitrary numbers chosen from 2 or more integers. The terminal hydroxyl group-containing phenylene ether oligomer represented by the chemical formula (13) may be one having n as a single compound, but may contain a plurality of components having different n. When a plurality of components having different n are included, it is preferable to use a component having an average composition in the range of 1 <n ≦ 10 as a part of the monomer component. More preferably, an average composition having a range of 2 ≦ n ≦ 10 is used as a part of the monomer component. When n as an average composition is smaller than 1, the glass transition temperature of the obtained polymer tends to be high, and the processability as a fuel cell material tends to decrease. When the average composition is n> 10, the glass transition temperature is low. This is because the heat resistance when used as a fuel cell material tends to be insufficient. In addition, when the terminal hydroxyl group-containing phenylene ether oligomer represented by the chemical formula (13) includes a plurality of components different from n, the average composition is determined by NMR or the like, and the abundance of components different from n is GPC or the like. Can be determined.

（ただし、Ｚ^１は独立して酸素原子又は硫黄原子のいずれかを、Ｚ^２は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。また、Ａｒ^１が化学式（３）および（４）の両方を同時に含む場合は、上記化学式（１）とともに下記化学式（５）および（６）の分子構造を同時に含む。）

（ただし、Ａｒ^２，Ａｒ^３は２価の芳香族結合ユニットを、Ｚ^３，Ｚ^４は独立して酸素原子又は硫黄原子のいずれかを、Z^６は酸素原子、硫黄原子、−Ｃ（ＣＨ_３）_２−基、−Ｃ（ＣＦ_３）_２−基、−ＣＨ_２−基、シクロヘキシル基のいずれかを示す。 Moreover, preferred molecular structure of the chemical formula (1) is a case Ar ¹ simultaneously contain both of the molecular structure of the following chemical formula (3) and (4).

(However, one of ^{Z 1} is independently oxygen atom or sulfur atom, ^{Z 2} is an oxygen atom, a sulfur atom, -C _{(CH 3) 2} - group, -C _{(CF 3) 2} - group, -CH _In the case where Ar ¹ includes both of the chemical formulas (3) and (4), the molecule represented by the following chemical formulas (5) and (6) together with the chemical formula (1) is shown. Including structure at the same time.)

(However, Ar ² and Ar ³ are divalent aromatic bond units, Z ³ and Z ⁴ are independently oxygen atoms or sulfur atoms, Z ⁶ is an oxygen atom, sulfur atom, and —C (CH _{3) 2} - group shown, one of the cyclohexyl groups - group, -C _{(CF 3) 2} - group, -CH _2.

The sulfonic acid group-containing polymer of the present invention, wherein Ar ¹ in the chemical formula (1) includes a structural unit represented by the chemical formulas (3) and (4) and a structural unit represented by the chemical formulas (5) and (6). In the above, each structural unit may be bonded at random, or the same repeating unit may be bonded continuously. In that case, all types of repeating units may be continuously bonded, or only some types may be continuously bonded.

  Y represents H or a monovalent cation, but when used as a proton exchange membrane of a fuel cell, Y is preferably H. In processing such as dissolution, molding, and film formation, it is preferable that Y is a monovalent cation rather than H because the thermal stability of the sulfonic acid group is increased. Examples of monovalent cations include alkali metal ions such as Na, K and Li, ammonium ions and quaternary amine salts, and alkali metal ions such as Na, K and Li are preferred. The sulfonic acid group that is an alkali metal salt can be converted to a sulfonic acid group by treating the polymer with a strong acid such as sulfuric acid, hydrochloric acid, perchloric acid, or an aqueous solution thereof. A polymer having a sulfonic acid group exhibits high proton conductivity, and can be used as a proton exchange resin or a proton exchange membrane. Among them, the proton exchange membrane can be used as an electrolyte of a polymer electrolyte fuel cell, and a fuel cell having excellent performance can be obtained by using the polymer of the present invention.

Z ¹ , Z ³ and Z ⁴ each independently represent either an O or S atom. It is preferable that all of Z ¹ , Z ³ , and Z ⁴ are O atoms because the cost and toxicity of the monomer are not increased, and coloring during polymerization hardly occurs. The oxidation resistance is higher when the S atom is used than the O atom. Z ² and Z ⁵ each independently represent an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, or a cyclohexyl group. . Among these, an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, and a cyclohexyl group are preferable, and an O atom and an S atom are more preferable.

Of Z ^{1 to} Z ⁵ , at least Z ² and Z ⁵ are preferably S atoms in terms of oxidation resistance, and more preferably Z ¹ and Z ⁴ are S atoms. More preferably, all are S atoms.

Ar ² and Ar ³ in chemical formula (5) and chemical formula (6) are preferably aromatic groups having an electron-withdrawing group. Examples of electron withdrawing groups include sulfone groups, carbonyl groups, sulfonyl groups, phosphine groups, cyano groups, trifluoromethyl groups and other perfluoroalkyl groups, nitro groups, halogen groups, etc., cyano groups, sulfone groups A carbonyl group is preferred. Furthermore, Ar ² and Ar ³ are preferably one or more groups selected from molecular structures represented by the following chemical formulas (9) to (12). The structure of Chemical Formula 9 is preferable because the solubility in a solvent is increased. Moreover, since it becomes possible to provide photocrosslinkability to a polymer, it is preferable that it is a molecular structure of Chemical formula (10). Moreover, since it is the molecular structure of Chemical formula (11) or (12), since the swelling property of a polymer becomes small, it is preferable. Among the chemical formulas (9) to (12), the molecular structure of the chemical formula (11) or (12) is preferable, and the molecular structure of the chemical formula (12) is most preferable.

The molar ratio of the repeating molecular structure represented by the chemical formula (1) and the chemical formulas (5) and (6) when the Ar ¹ is represented by the chemical formulas (3) and (4), and the other repeating structures, It is preferable to satisfy Formulas 1-3. Other repeating molecular structures are not particularly limited, but for example, those containing a phosphonic acid group or a phosphoric acid group are preferred because the oxidation resistance is improved. In addition, if it contains an alkyl group such as a methyl group or a group having crosslinkability such as an allyl group, an ethynyl group, or a maleimide group, the polymer is imparted with a crosslinkability to improve the durability and strength of the ion exchange membrane. This is preferable.

(Formula 1) 0.9 ≦ (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) ≦ 1.0
(Formula 2) 0.05 ≦ (n1 + n2) / (n1 + n2 + n3 + n4) ≦ 0.7
(Formula 3) 0.01 ≦ (n2 + n4) / (n1 + n2 + n3 + n4) ≦ 0.95

(In the above formula, n1 is the mol% of the repeating molecular structure represented by the chemical formula (1) when Ar ¹ is the chemical formula (3), and n2 is the chemical formula (1 when the Ar ¹ is the chemical formula (4) (1). N3 represents the mol% of the repeating molecular structure represented by the chemical formula (5), n4 represents the mol% of the repeating molecular structure represented by the chemical formula (6), n5 Represents the mol% of other repeating molecular structures, respectively.)

  A preferred range of the ratio of the repeating units represented by the chemical formulas (1), (5), and (6) in the polymer to all the repeating units is represented by Formula 1. (N1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) is preferably in the range of 0.9 to 1.0, more preferably in the range of 0.95 to 1.0, and in the range of 0.96 to 1.0. More preferably it is. When it contains other repeating units other than chemical formula (1), (5), (6), it is more preferable that it is the range of 0.001-0.04 with respect to all the repeating units.

  In the repeating units represented by the chemical formulas (1), (5) and (6), the preferred range of the repeating unit containing a sulfonic acid group is represented by Formula 2, (n1 + n2) / (n1 + n2 + n3 + n4) is 0.05 It is preferable to be in the range of -0.7. If (n1 + n2) / (n1 + n2 + n3 + n4) is lower than 0.05, sufficient ion conductivity cannot be obtained, and if it is higher than 0.7, the swellability becomes remarkably large or water-soluble. This is not preferable because it is difficult to use as an ion exchange membrane.

  The preferred range of the total ratio of the molecular structures represented by Chemical Formula 2 and Chemical Formula 4 in the repeating units represented by Chemical Formulas (1), (5), and (6) is represented by Formula 3. (N2 + n4) / (n1 + n2 + n3 + n4) is preferably in the range of 0.01 to 0.95. If (n2 + n4) / (n1 + n2 + n3 + n4) is smaller than 0.01, a sufficient improvement effect cannot be obtained, and if it is larger than 0.95, the swelling property of the film increases, which is not preferable.

  When the resin composition of the present invention using the sulfonic acid group-containing polymer having the chemical formulas (1), (5) and (6) described above is used as a proton exchange membrane of a direct methanol fuel cell using a methanol aqueous solution directly as a fuel. It is preferable that the following mathematical formulas 1, 4 and 5 are satisfied.

(Formula 1) 0.9 ≦ (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) ≦ 1.0
(Formula 4) 0.05 ≦ (n1 + n2) / (n1 + n2 + n3 + n4) ≦ 0.5
(Formula 5) 0.05 ≦ (n2 + n4) / (n1 + n2 + n3 + n4) ≦ 0.95

(In the above formula, n1 is the mol% of the repeating molecular structure represented by the chemical formula (1) when Ar ¹ is the chemical formula (3), and n2 is the chemical formula (1 when the Ar ¹ is the chemical formula (4) (1). N3 represents the mol% of the repeating molecular structure represented by the chemical formula (5), n4 represents the mol% of the repeating molecular structure represented by the chemical formula (6), n5 Represents the mol% of other repeating molecular structures, respectively.)

  In Formula 1, (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) is preferably in the range of 0.9 to 1.0, more preferably in the range of 0.95 to 1.0, and 0.96 to 1. A range of 0 is more preferable. When other repeating units other than the above chemical formulas (1), (5), and (6) are included, it is more preferably in the range of 0.001 to 0.04 with respect to all the repeating units.

  In Formula 4, (n1 + n2) / (n1 + n2 + n3 + n4) is preferably in the range of 0.05 to 0.5. When (n1 + n2) / (n1 + n2 + n3 + n4) is smaller than 0.05, sufficient proton conductivity cannot be obtained, and the output of the fuel cell is lowered, which is not preferable. If (n1 + n2) / (n1 + n2 + n3 + n4) is greater than 0.5, the amount of methanol permeating through the membrane becomes too large and the output of the fuel cell is undesirably reduced. A more preferable range of (n1 + n2) / (n1 + n2 + n3 + n4) is 0.07 to 0.4. Further, when the concentration of the aqueous methanol solution used as the fuel is low, the larger (n1 + n2) / (n1 + n2 + n3 + n4) is, the higher the proton conductivity is, and the higher the output of the fuel cell. On the other hand, when a high-concentration methanol aqueous solution is used, a decrease in (n1 + n2) / (n1 + n2 + n3 + n4) can suppress a decrease in output due to the permeation of methanol and increase the output of the fuel cell.

  In Formula 5, (n2 + n4) / (n1 + n2 + n3 + n4) is preferably in the range of 0.05 to 0.95. If (n2 + n4) / (n1 + n2 + n3 + n4) is smaller than 0.05, poor bonding is likely to occur when the electrode or catalyst is bonded to the ion exchange membrane, and if it is larger than 0.95, the swelling property becomes too large. . A more preferable range of (n2 + n4) / (n1 + n2 + n3 + n4) is a range of 0.2 to 0.8. When (n1 + n2) / (n1 + n2 + n3 + n4) is smaller than 0.2, (n2 + n4) / (n1 + n2 + n3 + n4) is preferably in the range of 0.4 to 0.8. When the value of (n1 + n2) / (n1 + n2 + n3 + n4) is larger than 0.2, (n2 + n4) / (n1 + n2 + n3 + n4) is preferably in the range of 0.1 to 0.5.

  When the resin composition of the present invention using the sulfonic acid group-containing polymer having the chemical formulas (1), (5) and (6) is used as a proton exchange membrane of a fuel cell using hydrogen as a fuel, It is preferable that Formulas 1, 6, and 7 are satisfied.

(Formula 1) 0.9 ≦ (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) ≦ 1.0
(Formula 6) 0.3 ≦ (n1 + n2) / (n1 + n2 + n3 + n4) ≦ 0.7
(Formula 7) 0.01 ≦ (n2 + n4) / (n1 + n2 + n3 + n4) ≦ 0.25

(In the above formula, n1 is the mol% of the repeating molecular structure represented by chemical formula (1) when Ar ¹ is chemical formula (3), and n2 is the chemical formula (1 when Ar ¹ is chemical formula (4) (1). N3 represents the mol% of the repeating molecular structure represented by the chemical formula (5), n4 represents the mol% of the repeating molecular structure represented by the chemical formula (6), n5 Represents the mol% of other repeating molecular structures, respectively.)

  In Formula 1, (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) is preferably in the range of 0.9 to 1.0, more preferably in the range of 0.95 to 1.0, and 0.96 to 1. A range of 0 is more preferable. When other repeating units other than chemical formulas 1 to 4 are included, it is more preferably in the range of 0.001 to 0.04 with respect to all the repeating units.

  In Formula 6, (n1 + n2) / (n1 + n2 + n3 + n4) is preferably in the range of 0.3 to 0.7. When (n1 + n2) / (n1 + n2 + n3 + n4) is smaller than 0.3, sufficient proton conductivity cannot be obtained, and the output of the fuel cell is lowered, which is not preferable. If (n1 + n2) / (n1 + n2 + n3 + n4) is greater than 0.7, the film swells too much, and breakage and output decrease are liable to occur. A more preferable range of (n1 + n2) / (n1 + n2 + n3 + n4) is 0.35 to 0.7, and more preferably 0.4 to 0.5.

  In Formula 7, (n2 + n4) / (n1 + n2 + n3 + n4) is preferably in the range of 0.01 to 0.25. If (n2 + n4) / (n1 + n2 + n3 + n4) is smaller than 0.01, poor bonding is likely to occur when the electrode or catalyst is bonded to the ion exchange membrane, and if it is larger than 0.25, the swelling property becomes too large, which is not preferable. . A more preferable range of (n2 + n4) / (n1 + n2 + n3 + n4) is a range of 0.1 to 0.2.

  In the sulfonic acid group-containing polymer of the present invention comprising the above-described chemical formulas (1), (5) and (6), chemical formulas (21A) to (21BJ) which are specific examples of preferred structures are shown below. However, the range is not limited to these.

  Among the chemical formulas 21A to 21BJ, the chemical formulas 21A, 21C, 21E, 21J, 21M, 21N, 21BE, and 21BF are preferable because of excellent proton conductivity and swelling resistance, and the chemical formulas 21A, 21C, and 21E are more preferable, and the chemical formula 21A is more preferable. Most preferred. Further, the structure represented by the chemical formula 21BC is preferable because the oxidation resistance of the polymer is improved. In addition, when the structure is represented by the chemical formula 21BD, since the polymer has crosslinkability, physical properties and durability can be improved.

In the above chemical formulas 21A to 21BJ, n, m, o, p, and q preferably satisfy the following formulas 8 to 10.
(Formula 8) 0.9 ≦ (n + m + o + p) / (n + m + o + p + q) ≦ 1.0
(Formula 9) 0.05 ≦ (n + m) / (n + m + o + p) ≦ 0.7
(Formula 10) 0.01 ≦ (m + p) / (n + m + o + p) ≦ 0.95

  In Formula 8, (n + m + o + p) / (n + m + o + p + q) is preferably in the range of 0.9 to 1.0. (N + m + o + p) / (n + m + o + p + q) is more preferably in the range of 0.95 to 1.0, and still more preferably in the range of 0.96 to 1.0. When q is not 0, (q) / (n + m + o + p + q) is more preferably in the range of 0.001 to 0.04.

  In Formula 9, (n + m) / (n + m + o + p) is preferably in the range of 0.05 to 0.7. When (n + m) / (n + m + o + p) is lower than 0.05, sufficient ion conductivity cannot be obtained, which is not preferable. When (n + m) / (n + m + o + p) is higher than 0.7, the swellability becomes remarkably large or becomes water-soluble, which makes it difficult to use as an ion exchange membrane.

  In Formula 10, (m + p) / (n + m + o + p) is preferably in the range of 0.01 to 0.95. When (m + p) / (n + m + o + p) is smaller than 0.01, a sufficient improvement effect cannot be obtained, and it is not preferable, and when it is larger than 0.95, the film swellability increases, which is not preferable.

Ar ^{1 includes the} structural unit represented by the chemical formula (1) represented by the chemical formulas (3) and (4) and the structural unit represented by the chemical formula (5) and (6). In the containing polymer, the repeating structure represented by the chemical formula (1) and the chemical formula (6) when Ar ¹ is represented by the chemical formula (4) increases the flexibility of the polymer and makes it difficult to break against deformation. In addition, the effect of increasing the bondability with the electrode due to the decrease in the glass transition temperature is brought about. Further, when Ar ¹ is represented by the above chemical formula (3), the repeating structure represented by the above chemical formula (1) and chemical formula (5) reduces the swelling property of the whole polymer or the methanol permeability. Has an effect.

  When the ion exchange membrane of the present invention is used as a proton exchange membrane of a direct methanol fuel cell that directly uses an aqueous methanol solution as a fuel, it is preferable that the following mathematical formulas 8, 11, and 12 are satisfied.

(Formula 8) 0.9 ≦ (n + m + o + p) / (n + m + o + p + q) ≦ 1.0
(Formula 11) 0.05 ≦ (n + m) / (n + m + o + p) ≦ 0.5
(Formula 12) 0.05 ≦ (m + p) / (n + m + o + p) ≦ 0.95

  In Formula 8, (n + m + o + p) / (n + m + o + p + q) is preferably in the range of 0.9 to 1.0. (N + m + o + p) / (n + m + o + p + q) is more preferably in the range of 0.95 to 1.0, and still more preferably in the range of 0.96 to 1.0. When q is not 0, (q) / (n + m + o + p + q) is more preferably in the range of 0.001 to 0.04.

  In Formula 11, (n + m) / (n + m + o + p) is preferably in the range of 0.05 to 0.5. When (n + m) / (n + m + o + p) is smaller than 0.05, sufficient proton conductivity cannot be obtained, and the output of the fuel cell is lowered, which is not preferable. If (n + m) / (n + m + o + p) is greater than 0.5, the amount of methanol permeating through the membrane becomes too large, and the output of the fuel cell is unfavorable. A more preferable range of (n + m) / (n + m + o + p) is 0.07 to 0.4. In addition, when the concentration of the aqueous methanol solution used as the fuel is low, the higher the (n + m) / (n + m + o + p), the higher the proton conductivity, and the higher the output of the fuel cell. On the other hand, when a high-concentration aqueous methanol solution is used, a smaller (n + m) / (n + m + o + p) can suppress a decrease in output due to the permeation of methanol and increase the output of the fuel cell.

  In Formula 12, the value of (m + p) / (n + m + o + p) is preferably in the range of 0.05 to 0.95. If (m + p) / (n + m + o + p) is less than 0.05, bonding failure is likely to occur when the electrode or catalyst is bonded to the ion exchange membrane, and if it is greater than 0.95, the swelling property becomes too large, which is not preferable. . A more preferable range of (m + p) / (n + m + o + p) is a range of 0.2 to 0.8. When the value of (n + m) / (n + m + o + p) is smaller than 0.25, (m + p) / (n + m + o + p) is preferably in the range of 0.4 to 0.8. When the value of (n + m) / (n + m + o + p) is larger than 0.25, (m + p) / (n + m + o + p) is preferably in the range of 0.1 to 0.5.

  When the resin composition of the present invention using the sulfonic acid group-containing polymer having the chemical formulas (1), (5) and (6) is used as a proton exchange membrane of a fuel cell using hydrogen as a fuel, It is preferable that Expressions 8, 13, and 14 are satisfied.

(Formula 8) 0.9 ≦ (n + m + o + p) / (n + m + o + p + q) ≦ 1.0
(Formula 13) 0.3 ≦ (n + m) / (n + m + o + p) ≦ 0.7
(Formula 14) 0.01 ≦ (m + p) / (n + m + o + p) ≦ 0.25

  In Formula 8, (n + m + o + p) / (n + m + o + p + q) is preferably in the range of 0.9 to 1.0. (N + m + o + p) / (n + m + o + p + q) is more preferably in the range of 0.95 to 1.0, and still more preferably in the range of 0.96 to 1.0. When q is not 0, (q) / (n + m + o + p + q) is more preferably in the range of 0.001 to 0.04.

  In Formula 13, (n + m) / (n + m + o + p) is preferably in the range of 0.3 to 0.7. When (n + m) / (n + m + o + p) is smaller than 0.3, sufficient proton conductivity cannot be obtained, and the output of the fuel cell is lowered, which is not preferable. If (n + m) / (n + m + o + p) is greater than 0.7, the film swells too much, and breakage or output reduction is likely to occur, which is not preferable. A more preferable range of (n + m) / (n + m + o + p) is 0.35 to 0.7, and a more preferable range is 0.4 to 0.5.

  In Formula 14, the value of (m + p) / (n + m + o + p) is preferably in the range of 0.01 to 0.25. If (m + p) / (n + m + o + p) is smaller than 0.01, bonding failure is likely to occur when the electrode or catalyst is bonded to the ion exchange membrane, and if it is larger than 0.25, the swellability becomes too large. . A more preferable range of (m + p) / (n + m + o + p) is a range of 0.1 to 0.2.

  The sulfonic acid group-containing polymer composed of the above chemical formulas (1), (5), and (6) is polymerized by an aromatic nucleophilic substitution reaction from a mixture of monomers containing the compounds represented by the chemical formulas 22 to 25 as essential components. be able to.

In Chemical Formulas 22 to 25, X represents a —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and Z ⁷ and Z ¹⁰ each independently represent Any one of Cl atom, F atom and nitro group, Z ⁸ and Z ¹¹ are each independently OH group, SH group, —O—NH—C (═O) —R group, —S—NH—C. Any one of (= O) -R groups [R represents an aromatic or aliphatic hydrocarbon group. Z ⁹ is an O atom, S atom, —C (CH ₃ ) ₂ — group, —C (CF ₃ ) ₂ — group, —CH ₂ — group, or cyclohexyl group, and Ar ³ is a molecule. And an aromatic group having an electron-withdrawing group such as a perfluoroalkyl group such as a sulfone group, a carbonyl group, a sulfonyl group, a phosphine group, a cyano group or a trifluoromethyl group, a nitro group or a halogen group.

  Specific examples of the compound represented by Chemical Formula 22 include 3,3′-disulfo-4,4′-dichlorodiphenyl sulfone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, 3,3′- Disulfo-4,4′-dichlorodiphenyl ketone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, 3,3′-disulfobutyl-4,4′-dichlorodiphenyl sulfone, 3,3′-disulfobutyl- 4,4′-difluorodiphenyl sulfone, 3,3′-disulfobutyl-4,4′-dichlorodiphenyl ketone, 3,3′-disulfobutyl-4,4′-difluorodiphenyl sulfone, and their sulfonic acid groups are monovalent Examples include salts with cation species. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto. Examples of the compound represented by the chemical formula 22 having a sulfonic acid group as a salt include sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone, 3,3′-disulfonic acid. Sodium-4,4′-difluorodiphenylsulfone, sodium 3,3′-disulfonate-4,4′-dichlorodiphenylketone, sodium 3,3′-disulfonate-4,4′-difluorodiphenylsulfone, 3,3 'Sodium disulfonate-4,4'-difluorodiphenyl ketone, potassium 3,3'-disulfonate 4,4'-dichlorodiphenyl sulfone, potassium 3,3'-disulfonate 4,4'-difluorodiphenyl sulfone, 3, , 3′-Disulfonic acid potassium 4,4′-dichlorodiphenyl ketone, 3,3′-disulfone Potassium 4,4'-difluoro diphenyl sulfone, etc. 3,3'-disulfonic acid potassium 4,4'-difluoro diphenyl ketone and the like.

  Specific examples of the compound represented by Chemical Formula 23 include 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 4 , 4′-thiobisbenzenethiol, 4,4′-oxybisbenzenethiol, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether, 1,1-bis (4-hydroxyphenyl) cyclohexane, etc. 4,4′-thiobisbenzenethiol, bis (4-hydroxyphenyl) sulfide, and 1,1-bis (4-hydroxyphenyl) cyclohexane are preferable.

  The monomer having the structure represented by Chemical Formula 23 increases the flexibility of the polymer and makes it difficult to break against deformation, and the effect of increasing the bondability with the electrode by lowering the glass transition temperature. ing.

  Examples of the compound represented by Chemical Formula 24 include compounds having a leaving group in a nucleophilic substitution reaction such as halogen and nitro group on the same aromatic ring and an electron-withdrawing group that activates the same. Specific examples include 2,6-dichlorobenzonitrile, 2,4-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2,4-difluorobenzonitrile, 4,4′-dichlorodiphenylsulfone, 4,4 ′. -Difluorodiphenyl sulfone, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, decafluorobiphenyl, and the like, but not limited thereto, other aromatics active in aromatic nucleophilic substitution reaction A group dihalogen compound, an aromatic dinitro compound, an aromatic dicyano compound, and the like can also be used.

  Examples of the compound represented by Chemical Formula 25 include 4,4'-biphenol, 4,4'-dimercaptobiphenol, and 4,4'-biphenol is preferred.

  In the above aromatic nucleophilic substitution reaction, other various activated dihalogen aromatic compounds, dinitroaromatic compounds, bisphenol compounds, and bisthiophenol compounds can be used in combination with the compounds represented by the chemical formulas 22 to 25. .

  In the aromatic nucleophilic substitution reaction for obtaining a sulfonic acid group-containing polymer in the present invention, a monomer giving a structure other than the chemical formulas (1), (5), (6) and (8) is used in combination. Can do. Examples of the activated difluoroaromatic compound and dichloroaromatic compound that can be used in this case include decafluorobiphenyl, decafluorodiphenyl ether, decafluorobenzophenone, 2,4-dichlorobenzonitrile, 2,4-difluorobenzonitrile, 4, Examples of compounds such as 4′-dichlorobenzophenone, 4,4′-dichlorodiphenylsulfone, 4,4′-difluorobenzophenone, 4,4′-difluorodiphenylsulfone, and the like are not limited thereto, but are aromatic. Other aromatic dihalogenated compounds, aromatic dinitro compounds, aromatic dicyano compounds and the like that are active in nucleophilic substitution reactions can also be used. These compounds may be used alone or as a mixture of two or more.

  In addition, aromatic diol components having molecular structures other than the above-described chemical formulas (1), (5), (6), and (8) in the sulfonic acid group-containing polymer also obtain the sulfonic acid group-containing polyarylene ether polymer in the present invention. Can be used for aromatic nucleophilic substitution reactions. Examples of these are 4,4′-biphenol, bis (4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, bis ( 4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) Propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydride) Xylphenyl) fluorene, 9,9-bis (3-phenyl-4-hydroxyphenyl) fluorene, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcin, 1,4-dihydroxynaphthalene, 1,8 -Dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, bis (4-hydroxyphenyl) ketone, bis ( 4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) thioether, bis (4-hydroxyphenoxy) -1,4-benzene, bis (4-hydroxyphenoxy) -1,3-benzene, phenolphthalein, etc. use DOO but can, also possible to use various types of aromatic diols which can be used for the polymerization of polyarylene ether-based compound according to aromatic nucleophilic substitution reaction in addition to this. In addition, a substituent such as a methyl group, a halogen, a cyano group, a sulfonic acid group, and a salt compound thereof may be bonded to these aromatic diols. The kind of substituent is not particularly limited, and is preferably 0 to 2 per aromatic ring. Furthermore, diphenylthioether-4,4'-dithiol, 1,4-benzenedithiol, 1,3-benzenedithiol, and the like capable of reacting in the same manner as aromatic diols can also be used. These aromatic diols can be used alone, or a plurality of aromatic diols can be used in combination.

  In the polymerization of the sulfonic acid group-containing polymer of the present invention, a halogenated aromatic hydroxy compound can be added as a reactive monomer component for polymerization. The halogenated aromatic hydroxy compound used in this case is not particularly limited, but 4-hydroxy-4′-chlorobenzophenone, 4-hydroxy-4′-fluorobenzophenone, 4-hydroxy-4′-chlorodiphenylsulfone. 4-hydroxy-4′-fluorodiphenylsulfone, 4-chloro-4 ′-(p-hydroxyphenyl) diphenylsulfone, 4-fluoro-4 ′-(p-hydroxyphenyl) benzophenone, and the like. it can. These can be used alone or can be used as a mixture of two or more.

  In addition, the sulfonic acid group-containing polymer of the present invention may contain a component that crosslinks by heat and / or light in the molecular chain, that is, as the main chain, side chain, or terminal group of the polymer. Examples of thermally crosslinkable groups include reactive unsaturated bond-containing components such as ethylene group, ethynyl group, and ethynylene group, but are not limited to these, and a new reaction between polymer chains is caused by reaction by heat. Any material that can form a bond may be used. Examples of photocrosslinkable groups include benzophenone groups, α-diketone groups, acyloin groups, acyloin ether groups, benzyl alkyl ketal groups, acetophenone groups, polynuclear quinones, thioxanthone groups, acylphosphine groups, and ethylenically unsaturated groups. Can be mentioned. Among them, a combination of a group capable of generating a radical by light such as a benzophenone group and a group capable of reacting with a radical such as an aromatic group having a hydrocarbon group such as a methyl group or an ethyl group is preferable. When using ethylenically unsaturated groups, photopolymerization of benzophenones, α-diketones, acyloins, acyloin ethers, benzyl alkyl ketals, acetophenones, polynuclear quinones, thioxanthones, acylphosphines It is preferable to add an initiator.

  In addition, when the above-mentioned crosslinkable terminal structure is introduced, it can be obtained by adding a monofunctional end-blocking agent that gives a crosslinkable group-containing terminal structure during the polymerization of the sulfonic acid group-containing polymer of the present invention. . Examples of monofunctional end-capping agents are specifically 3-fluoropropene, 3-fluoro-1-propyne, 4-fluoro-1-butene, 4-fluoro-1-butyne, 3-fluorocyclohexene, 4 -Fluorostyrene, 3-fluorostyrene, 2-fluorostyrene, 4-fluoroethynylbenzene, 3-fluoroethynylbenzene, α-fluoro-4-ethynyltoluene, 4-fluorostilbene, 4- (phenylethynyl) fluorobenzene, 3 -(Phenylethynyl) fluorobenzene, 3-chloropropene, 3-chloro-1-propyne, 4-chloro-1-butene, 4-chloro-1-butyne, 3-chlorocyclohexene, 4-chlorostyrene, 3-chloro Styrene, 2-chlorostyrene, 4-chloroethynylbenzene, 3-chloroethini Benzene, α-chloro-4-ethynyltoluene, 4-chlorostilbene, 4- (phenylethynyl) chlorobenzene, 3- (phenylethynyl) chlorobenzene, 3-hydroxypropene, 3-hydroxy-1-propyne, 4-hydroxy-1 -Butene, 4-hydroxy-1-butyne, 4-hydroxystyrene, 3-hydroxystyrene, 2-hydroxystyrene, 4-hydroxyethynylbenzene, 3-ethynylphenol, 4-ethynylbenzyl alcohol, 4-hydroxystilbene, 4- (Phenylethynyl) phenol, 3- (phenylethynyl) phenol, 4-chlorobenzophenone, 4-fluorobenzophenone, 4-hydroxybenzophenone, 4-methylphenol, 3-methylphenol, 2-methylphenol, 4 Ethylphenol, 3-ethylphenol, 4-propyl phenol, 4-butylphenol, 4-pentylphenol, 4-benzyl-phenol, and the like. These crosslinking group-containing end-capping agents may be used alone or in combination of two or more.

  Specific examples of the monomer having a crosslinkable group include 1-butene-3,4-diol, 3,5-dihydroxystyrene, 3,5-dihydroxystilbene, 1-butyne-3,4-diol, -Butene-3,4-diol, 2,4-hexadiyne-1,6-diol, 2-ethynylhydroquinone, 2- (phenylethynyl) hydroquinone, 5-ethynylresorcin, 2-butene-1,4-diol, 4 , 4′-dihydroxystilbene, 1,4-butynediol, 1,2-bis (4-hydroxyphenyl) acetylene, 1,2-bis (3-hydroxyphenyl) acetylene, 3,3-difluoropropene, 3,3 -Difluoropropyne, 3,3,3-trifluoropropyne, 3,4-difluoro-1-butene, 1,4-difluoro-2- Butene, 3,4-difluoro-1-butyne, 1,4-difluoro-2-butyne, 1,6-difluoro-2,4-hexadiyne, 3,4-difluorostyrene, 2,6-difluorostyrene, 2, 5-difluoroethynylbenzene, 3,5-difluoroethynylbenzene, α, α-difluoro-4-ethynyltoluene, α, α, α-trifluoro-4-ethynyltoluene, 2,4-difluorostilbene, 4,4 ′ -Difluorostilbene, 1,2-bis (4-fluorophenyl) acetylene, 3,4-difluoro (phenylethynyl) benzene, 3,3-dichloropropene, 3,3-dichloropropyne, 3,3,3-trichloro Propyne, 3,4-dichloro-1-butene, 1,4-dichloro-2-butene, 3,4-dichloro-1-butyne, 1,4 Dichloro-2-butyne, 3,4-dichlorostyrene, 2,6-dichlorostyrene, 2,4-difluorocinamic acid, 2,5-dichloroethynylbenzene, 3,5-dichloroethynylbenzene, α, α-dichloro -4-ethynyltoluene, α, α, α-trichloro-4-ethynyltoluene, 2,4-dichlorostilbene, 4,4′-dichlorostilbene, 1,2-bis (4-chlorophenyl) acetylene, 3,4- Dichloro (phenylethynyl) benzene, 4,4′-dihydroxybenzophenone, 4,4′-dichlorobenzophenone, 4,4′-difluorobenzophenone, 4-chlorobenzophenone, 4-fluorobenzophenone, 4-hydroxybenzophenone 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydro) Cyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy-3) , 5-dimethylphenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, 4- Benzylresorcin, 2,5-dimethylresorcin, 4-ethylresorcin, etc. are mentioned. By adding these crosslinking group monomers in the polymerization of the polyarylene ether compound of the present invention, a crosslinking group can be introduced into the molecular chain.

  The sulfonic acid group-containing polymer of the present invention preferably has a sulfonic acid group content in the range of 0.3 to 5.0 meq / g. When it is less than 0.3 meq / g, there is a tendency that it does not show sufficient ionic conductivity when used as a polymer electrolyte membrane. Tend to be. The sulfonic acid group content can be determined by a titration method described later after the sulfonic acid group is converted to an acid type structure by an acidic aqueous solution treatment. In addition, Preferably it is 0.5-3.5 meq / g.

  The sulfonic acid group-containing polymer of the present invention preferably has a glass transition temperature between 130 ° C. and 220 ° C. When the glass transition temperature is lower than 130 ° C., the heat resistance when used as a polymer electrolyte membrane tends to be insufficient, and when the glass transition temperature is higher than 220 ° C., the electrolyte membrane / electrode composite This is because a tendency for processability to decrease when a body is produced begins to appear. When the glass transition temperature is between 130 ° C. and 220 ° C., the processability when producing the electrolyte membrane / electrode composite is excellent, and the heat resistance when used as a fuel cell is particularly good. In addition, the glass transition temperature said here can be determined by the dynamic viscoelasticity measurement mentioned later.

  When the sulfonic acid group-containing polymer of the present invention is polymerized by an aromatic nucleophilic substitution reaction, an activated difluoroaromatic compound and / or a dichloroaromatic compound and an aromatic diol are reacted in the presence of a basic compound. A polymer can be obtained. The polymerization can be carried out in the temperature range of 0 to 350 ° C., but is preferably 50 to 250 ° C. When the temperature is lower than 0 ° C., the reaction does not proceed sufficiently, and when the temperature is higher than 350 ° C., the polymer tends to be decomposed. The reaction can be carried out in the absence of a solvent, but is preferably carried out in a solvent. Examples of the solvent that can be used include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, diphenyl sulfone, sulfolane, and the like. And any solvent that can be used as a stable solvent in the aromatic nucleophilic substitution reaction. These organic solvents may be used alone or as a mixture of two or more. Examples of the basic compound include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and the like, and those that can convert an aromatic diol into an active phenoxide structure may be used. It can use without being limited to. In the aromatic nucleophilic substitution reaction, water may be generated as a by-product. In this case, regardless of the polymerization solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. As a method for removing water out of the system, a water-absorbing agent such as molecular sieve can also be used. When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the resulting polymer concentration is 5 to 50% by mass. When the amount is less than 5% by mass, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by mass, the viscosity of the reaction system becomes too high, and post-treatment of the reaction product tends to be difficult. For the polymerization, it is preferable to add monomers at the beginning of the reaction to form a polymer having a highly random chain distribution. After completion of the polymerization reaction, the solvent is removed from the reaction solution by evaporation, and the residue is washed as necessary to obtain the desired polymer. In addition, the polymer can be obtained by precipitating the polymer as a solid by adding the reaction solution in a solvent having low polymer solubility, and collecting the precipitate by filtration. If necessary, a filtration treatment may be performed before the precipitation.

  The sulfonic acid group-containing polymer of the present invention preferably has a polymer log viscosity measured by a method described later of 0.1 or more. When the logarithmic viscosity is less than 0.1, the membrane tends to become brittle when molded as a polymer electrolyte membrane. The logarithmic viscosity is more preferably 0.3 or more. On the other hand, when the logarithmic viscosity exceeds 5, problems in processability such as difficulty in dissolving the polymer occur, which is not preferable. As the solvent for measuring the logarithmic viscosity, polar organic solvents such as N-methyl-2-pyrrolidone and N, N-dimethylacetamide can be generally used. Can also be measured.

  The acidic group-containing polybenzimidazole polymer in the present invention is characterized by including a molecular structure represented by the following chemical formula (7).

（Ｒ^１はイミダゾール環を形成できる４価の芳香族結合ユニットを、Ｒ^２は２価の芳香族結合ユニットを表し、Ｒ^１およびＲ^２はいずれも芳香環の単環であっても複数の芳香環の結合体あるいは縮合環であっても良く、安定な置換基を有していても良い。Ｚは、スルホン酸基および／またはホスホン酸基を表し、その一部が塩構造となっていても良い。ｎは２以上の任意の整数を示す。ｍ^１は１から４の整数を表す。）

(R ¹ represents a tetravalent aromatic bond unit capable of forming an imidazole ring, R ² represents a divalent aromatic bond unit, and R ¹ and R ² may be a single aromatic ring or a plurality of aromatic rings. It may be an aromatic ring conjugate or a condensed ring, and may have a stable substituent, Z represents a sulfonic acid group and / or a phosphonic acid group, and a part thereof has a salt structure. (N represents an arbitrary integer of 2 or more, and m ¹ represents an integer of 1 to 4.)

  The route for synthesizing the polybenzimidazole polymer of the present invention containing the structure represented by the above chemical formula (7) is not particularly limited, but usually from aromatic tetramines and their derivatives capable of forming an imidazole ring in the compound. It can be synthesized by a reaction of one or more compounds selected from the group consisting of one or more compounds selected from the group consisting of aromatic dicarboxylic acids and derivatives thereof. At that time, by using a dicarboxylic acid containing a sulfonic acid group or a phosphonic acid group or a salt thereof in the dicarboxylic acid to be used, a sulfonic acid group or a phosphonic acid group is introduced into the resulting polybenzimidazole. be able to. One or more dicarboxylic acids containing a sulfonic acid group or a phosphonic acid group can be used in combination, but a sulfonic acid group-containing dicarboxylic acid and a phosphonic acid group-containing dicarboxylic acid can be used simultaneously.

  Here, a benzimidazole-based binding unit that is a constituent element of the polybenzimidazole-based polymer of the present invention, an aromatic dicarboxylic acid binding unit having a sulfonic acid group and / or a phosphonic acid group, a sulfonic acid group, and a phosphonic acid group. It is preferable that the aromatic dicarboxylic acid bonding unit that is not present and other bonding units are bonded by random polymerization and / or alternating polymerization. Moreover, these polymerization formats are not limited to one type, and two or more polymerization types may coexist in the same compound.

Among the sulfonic acid group-containing polybenzimidazole-based polymers including the structural component represented by the above chemical formula (7), a binding unit represented by the structure represented by the following chemical formulas (14) and (15) is represented by n ¹ :( What is contained as a structural component in the molar ratio of 1-n ¹ ) is particularly preferable.

（ただし、Ａｒは２価の芳香族結合ユニットを表し、Ｘ^１は−Ｏ−、−ＳＯ_２−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＯＰｈＯ−からなる群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表す。また、ｎ^１（モル比）は、０．２≦ｎ^１≦１．０の式を満たす。ｍ^１は１から４の整数を表す。）

(However, Ar represents a divalent aromatic bond unit, and X ¹ consists of —O—, —SO ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, and —OPhO—. at least one element selected from the group, Ph represents a bivalent aromatic bond unit. in addition, ^{n 1} (molar ratio), the .m ¹ satisfying the formula of 0.2 ≦ ^{n 1} ≦ 1.0 Represents an integer from 1 to 4.)

In the above chemical formulas (14) and (15), if m ¹ is larger than 5, the water resistance of the resulting polymer tends to be inferior, and if n ¹ (molar ratio) is smaller than 0.2, sufficient It tends to show no ionic conductivity.

  Specific examples of the aromatic tetramine that gives the sulfonic acid group-containing polybenzimidazole-based polymer including the structural component represented by the above chemical formula (7) are not particularly limited. For example, 1, 2, 4, 5-tetraaminobenzene, 3,3′-diaminobenzidine, 3,3 ′, 4,4′-tetraaminodiphenyl ether, 3,3 ′, 4,4′-tetraaminodiphenylthioether, 3,3 ′, 4, 4'-tetraaminodiphenyl sulfone, 2,2-bis (3,4-diaminophenyl) propane, bis (3,4-diaminophenyl) methane, 2,2-bis (3,4-diaminophenyl) hexafluoropropane 1,4-bis (3,4-diaminophenoxy) benzene, and the like and derivatives thereof. Among these, 3,3 ′, 4,4′-tetraaminodiphenyl ether, 3,3 ′, 4,4′-tetraaminodiphenylsulfone, which can form a binding unit represented by the formula (14), 2,2-bis (3,4-diaminophenyl) propane, 2,2-bis (3,4-diaminophenyl) hexafluoropropane, 1,4-bis (3,4-diaminophenoxy) benzene and derivatives thereof Is particularly preferred.

  Specific examples of these aromatic tetramine derivatives include salts with acids such as hydrochloric acid, sulfuric acid and phosphoric acid. These compounds may be used alone or in combination. Furthermore, these compounds may contain known antioxidants such as tin (II) chloride and phosphorous acid compounds as necessary.

As the sulfonic acid group-containing dicarboxylic acid giving the structure of the above chemical formula (7), one containing 1 to 4 sulfonic acid groups in the aromatic dicarboxylic acid can be selected. For example, 2,5-dicarboxybenzenesulfonic acid, 3,5-dicarboxybenzenesulfonic acid, 2,5-dicarboxy-1,4-benzenedisulfonic acid, 4,6-dicarboxy-1,3-benzene Mention may be made of sulfonic acid-containing dicarboxylic acids such as disulfonic acid, 2,2′-disulfo-4,4′-biphenyldicarboxylic acid, 3,3′-disulfo-4,4′-biphenyldicarboxylic acid, and derivatives thereof. it can. Examples of the derivatives include alkali metal salts such as sodium and potassium, ammonium salts, and alkyl ammonium salts. The structure of the sulfonic acid group-containing dicarboxylic acid is not particularly limited to these. M ¹ in the above formula (7) is selected from integers of 1 to 4. If m ¹ is 5 or more, the water resistance of the polymer tends to decrease, such being undesirable.

  The sulfonic acid group-containing dicarboxylic acids can be introduced not only by themselves but also with dicarboxylic acids not containing sulfonic acid groups in the form of copolymerization. Examples of dicarboxylic acids not containing sulfonic acid groups and phosphonic acid groups that can be used with sulfonic acid group-containing dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl Common dicarboxylic acids reported as polyester raw materials such as dicarboxylic acid and 2,2-bis (4-carboxyphenyl) hexafluoropropane can be used, and are not limited to those exemplified here.

  The purity of the dicarboxylic acid containing a sulfonic acid group is not particularly limited, but is preferably 98% or more, and more preferably 99% or more. Polyimidazole polymerized using dicarboxylic acid containing sulfonic acid group as a raw material contains a sulfonic acid group because the degree of polymerization tends to be lower than when dicarboxylic acid containing no sulfonic acid group is used. It is preferable to use a dicarboxylic acid having as high purity as possible. When using a dicarboxylic acid not containing a sulfonic acid group together with a sulfonic acid group-containing dicarboxylic acid, the effect of the sulfonic acid can be clarified by setting the sulfonic acid group-containing dicarboxylic acid to 20 mol% or more of the total dicarboxylic acid. it can. In order to bring out the remarkable effect of sulfonic acid, it is more preferably 50 mol% or more. When the content of the aromatic dicarboxylic acid having a sulfonic acid group is less than 20 mol%, the conductivity of the polybenzimidazole polymer of the present invention tends to be low, which makes it unsuitable as a material for a solid polymer electrolyte. There is.

As the phosphonic acid group-containing polybenzimidazole-based polymer containing the structural component represented by the above chemical formula (7), a bonding unit represented by the structure represented by the following chemical formula (16) and formula (17) is represented by n ² : It is particularly preferable to contain a component with (1-n ²⁾ molar ratio.

（Ａｒは芳香族結合ユニットを表し、Ｘ²は−Ｏ−、−ＳＯ_２−、−Ｓ−、−ＣＨ_２−，−ＯＰｈＯ−より群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表すものとする。また、ｎ²（モル比）は、０．２≦ｎ²≦１．０の式を満たす。ｍ^１は１から４の整数を表す。）

(Ar represents an aromatic bond unit, X ² is at least one selected from the group consisting of —O—, —SO ₂ —, —S—, —CH ₂ —, —OPhO—, and Ph is a divalent group. (It is assumed that it represents an aromatic bond unit, and n ² (molar ratio) satisfies the formula of 0.2 ≦ n ² ≦ 1.0. M ¹ represents an integer of 1 to 4.)

In the above chemical formulas (16) and (17), if m ² is larger than 5, the resulting polymer tends to have poor water resistance, and if n ² (molar ratio) is smaller than 0.2, sufficient It tends to show no ionic conductivity.

  Specific examples of the aromatic tetramine that gives the phosphonic acid group-containing polyimidazole represented by the above chemical formula (7) are not particularly limited. For example, 1,2,4,5-tetraaminobenzene, 3 3,3′-diaminobenzidine, 3,3 ′, 4,4′-tetraaminodiphenyl ether, 3,3 ′, 4,4′-tetraaminodiphenylthioether, 3,3 ′, 4,4′-tetraaminodiphenylsulfone 2,2-bis (3,4-diaminophenyl) propane, bis (3,4-diaminophenyl) methane, 2,2-bis (3,4-diaminophenyl) hexafluoropropane, 1,4-bis ( 3,4-diaminophenoxy) benzene, and the like and their derivatives. Among these, 3,3 ′, 4,4′-tetraaminodiphenyl ether, 3,3 ′, 4,4′-tetraaminodiphenyl, which can form a binding unit represented by the above formula (16). Sulfone, 3,3 ′, 4,4′-tetraaminodiphenyl thioether, bis (3,4-diaminophenyl) methane, 1,4-bis (3,4-diaminophenoxy) benzene and derivatives thereof are particularly preferred.

  Specific examples of these aromatic tetramine derivatives include salts with acids such as hydrochloric acid, sulfuric acid and phosphoric acid. These compounds may be used alone or in combination. Furthermore, these compounds may contain known antioxidants such as tin (II) chloride and phosphorous acid compounds as necessary.

  An aromatic dicarboxylic acid having a phosphonic acid group and a derivative thereof used for synthesizing a polybenzimidazole polymer having a phosphonic acid group represented by the above chemical formula (7) are not particularly limited. A compound having 1 to 4 phosphonic acid groups in the dicarboxylic acid skeleton can be preferably used. Specific examples include aromatic dicarboxylic acids having a phosphonic acid group such as 2,5-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,5-bisphosphonoterephthalic acid, and derivatives thereof. Can be mentioned. It is not preferable to have 5 or more phosphonic acid groups in the aromatic dicarboxylic acid skeleton because the water resistance of the polymer tends to be lowered.

  Here, examples of the phosphonic acid derivatives of aromatic dicarboxylic acids having these phosphonic acid groups include alkali metal salts such as sodium and potassium, ammonium salts and alkylammonium salts. These compounds may be used alone or in combination. Furthermore, these compounds may contain known antioxidants such as tin (II) chloride and phosphorous acid compounds as necessary.

  The structure of the aromatic dicarboxylic acid having a phosphonic acid group is not limited to these, but an aromatic dicarboxylic acid having a phosphonic acid group of the phenylphosphonic acid group type shown here is preferred.

  The purity of the aromatic dicarboxylic acid having a phosphonic acid group used for the synthesis of the polybenzimidazole polymer in the present invention is not particularly limited, but is preferably 97% or more, more preferably 98% or more. The polybenzimidazole polymer polymerized using an aromatic dicarboxylic acid having a phosphonic acid group as a raw material has a degree of polymerization as compared with the case where an aromatic dicarboxylic acid having no sulfonic acid group and phosphonic acid group is used as a raw material. Since a tendency to decrease is observed, it is preferable to use an aromatic dicarboxylic acid having a phosphonic acid group as high as possible. That is, when the purity of the aromatic dicarboxylic acid is less than 97%, the degree of polymerization of the resulting polybenzimidazole polymer tends to be low, and it tends to be unsuitable as a solid polymer electrolyte material.

  The above-mentioned aromatic dicarboxylic acids having a phosphonic acid group may be used alone. However, by copolymerizing with an aromatic dicarboxylic acid not containing a phosphonic acid group, the polyphosphoric acid having a phosphonic acid group of the present invention is used. You may use for the synthesis | combination of a benzimidazole-type polymer. The sulfonic acid group that can be used together with the aromatic dicarboxylic acid having a phosphonic acid group and the aromatic dicarboxylic acid not having a phosphonic acid group are not particularly limited. For example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid General aromatic dicarboxylic acids reported as polyester raw materials such as diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl dicarboxylic acid, and 2,2-bis (4-carboxyphenyl) hexafluoropropane Can be used.

  These compounds may be used alone or in combination. Furthermore, these compounds may contain known antioxidants such as tin (II) chloride and phosphorous acid compounds as necessary.

  In the synthesis of the polybenzimidazole polymer in the present invention, when an aromatic dicarboxylic acid not having a phosphonic acid group is used together with an aromatic dicarboxylic acid having a phosphonic acid group, the aromatic carboxylic acid group has a phosphonic acid group in the wholly aromatic dicarboxylic acid. By blending the aromatic dicarboxylic acid content so as to be 20 mol% or more, the excellent effect of the polybenzimidazole polymer in the present invention having a phosphonic acid group can be clarified. Further, in order to bring out the remarkable effect of the polybenzimidazole polymer in the present invention having a phosphonic acid group, the content of the aromatic dicarboxylic acid having a phosphonic acid group is blended so as to be 50 mol% or more. More preferably. When the content of the aromatic dicarboxylic acid having a phosphonic acid group is less than 20 mol%, the electrical conductivity of the polybenzimidazole polymer in the present invention tends to be low, making it unsuitable as a solid polymer electrolyte material. There is.

Here, the aromatic dicarboxylic acid having a sulfonic acid group and the aromatic dicarboxylic acid having a phosphonic acid group may be used alone, but the sulfone in the present invention can be obtained by copolymerizing both of them. You may use for the synthesis | combination of the polybenzimidazole type polymer which has an acid group and / or a phosphonic acid group. In this case, it is particularly preferable that the binding unit represented by the structure represented by the following chemical formulas (18) and (19) is included as a constituent component at a molar ratio of n ³ : (1-n ³ ).

（Ａｒは芳香族結合ユニットを表し、Ｘ^３は−Ｏ−、−ＳＯ_２−、−Ｓ−、−ＣＨ_２−，−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＯＰｈＯ−より群から選ばれる１種以上であり、Ｐｈは２価の芳香族結合ユニットを表すものとする。また、ｎ^３（モル比）は、０．１≦ｎ^３≦０．９の式を満たす。ｍ^３およびｍ^４は１から４の整数を表す。）

(Ar represents an aromatic bond unit, and X ³ represents —O—, —SO ₂ —, —S—, —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, — It is at least one selected from the group consisting of OPhO—, Ph represents a divalent aromatic bond unit, and n ³ (molar ratio) is a formula of 0.1 ≦ n ³ ≦ 0.9. M ³ and m ⁴ represent an integer of 1 to 4.)

  At this time, the aromatic dicarboxylic acid having a sulfonic acid group and the aromatic dicarboxylic acid having a phosphonic acid group may be mixed and used alone, but the aromatic dicarboxylic acid having no sulfonic acid group and phosphonic acid group may be used. A polybenzimidazole-based polymer having a sulfonic acid group and / or a phosphonic acid group of the present invention may be synthesized by copolymerization reaction with an aliphatic dicarboxylic acid.

  Using one or more compounds selected from the group consisting of the above-mentioned aromatic tetramines and derivatives thereof, and one or more compounds selected from the group consisting of aromatic dicarboxylic acids and derivatives thereof, sulfonic acid groups and / or A method for synthesizing a polybenzimidazole-based polymer having a phosphonic acid group is not particularly limited.For example, JFWolfe, Encyclopedia of Polymer Science and Engineering, 2nd Ed., Vol. 11, P. 601 (1988) ) Can be synthesized by dehydration and cyclopolymerization using polyphosphoric acid as a solvent. Further, polymerization by a similar mechanism using a mixed solvent system of methanesulfonic acid / phosphorus pentoxide instead of polyphosphoric acid can be applied. In order to synthesize a polybenzimidazole polymer having high thermal stability, polymerization using polyphosphoric acid that is commonly used is preferred.

  Furthermore, in order to obtain the polybenzimidazole polymer in the present invention, for example, a precursor polymer having a polyamide structure is synthesized by a reaction in a suitable organic solvent or in the form of a mixed raw material monomer melt, A method of converting to a target polybenzimidazole structure by a cyclization reaction by an appropriate heat treatment can also be used.

  In addition, the reaction time when synthesizing the polybenzimidazole-based polymer in the present invention cannot be defined unconditionally because there is an optimum reaction time depending on the combination of individual raw material monomers, but it takes a long time as previously reported. In the applied reaction, in a system containing a raw material monomer such as an aromatic dicarboxylic acid having a sulfonic acid group and / or a phosphonic acid group, the thermal stability of the obtained polybenzimidazole polymer may be lowered. In this case, it is preferable to shorten the reaction time as long as the effect of the present invention is obtained. By shortening the reaction time as described above, a polybenzimidazole polymer having a sulfonic acid group and / or a phosphonic acid group can also be obtained in a highly heat stable state.

  The reaction temperature for synthesizing the polybenzimidazole polymer in the present invention cannot be defined unconditionally because there is an optimum reaction temperature depending on the combination of individual raw material monomers, but the reaction at a high temperature as reported conventionally. In a system containing a raw material monomer such as an aromatic dicarboxylic acid having a sulfonic acid group and / or a phosphonic acid group, control of the amount of sulfonic acid group and / or phosphonic acid group introduced into the obtained polybenzimidazole polymer In this case, it is preferable to lower the reaction temperature within a range where the effects of the present invention can be obtained. By lowering the reaction temperature in this way, it is possible to control the amount of sulfonic acid groups and / or phosphonic acid groups introduced into the polybenzimidazole polymer having a large amount of acidic groups.

  Further, after the synthesis of the polybenzimidazole polymer in the present invention, when the raw material monomer constituting the repeating unit is composed of plural kinds, the repeating units are bonded by random polymerization and / or alternating polymerization. As a result, the polymer electrolyte membrane has the characteristic of showing stable performance. Here, in order to synthesize the polybenzimidazole-based polymer in the present invention by random polymerization and / or alternating polymerization, all monomer materials are charged at a blending ratio that combines equivalence from the initial stage of polymerization. It is preferable to make.

  Polybenzimidazole polymers can also be synthesized by block polymerization instead of random polymerization or alternating polymerization, but in this case, the first component oligomer is used under the charging conditions of the monomer raw material with a blending ratio shifted in equivalence. It is preferable to carry out the polymerization after adding the monomer raw material and adjusting the blending ratio so that the equivalence is matched including the second component.

The weight average molecular weight of the polybenzimidazole polymer having a sulfonic acid group and / or a phosphonic acid group in the present invention is not particularly limited, but is 1,000 or more, preferably 3,000 or more. The molecular weight is preferably 1,000,000 or less, and more preferably 200,000 or less. When this molecular weight is less than 1,000, it becomes difficult to obtain a molded product having good properties from a polybenzimidazole polymer due to a decrease in viscosity. On the other hand, when the molecular weight exceeds 1,000,000, it becomes difficult to mold a polybenzimidazole polymer due to an increase in viscosity.
Further, the molecular weight of the polybenzimidazole polymer having a sulfonic acid group and / or a phosphonic acid group in the present invention can be substantially evaluated by a logarithmic viscosity when measured in concentrated sulfuric acid. The logarithmic viscosity of the polybenzimidazole polymer in the present invention is preferably 0.25 or more, and more preferably 0.40 or more. The logarithmic viscosity is preferably 10 or less, more preferably 8 or less. When this logarithmic viscosity is less than 0.25, it is difficult to obtain a molded product having good properties from the polybenzimidazole polymer due to the decrease in viscosity. On the other hand, when the logarithmic viscosity exceeds 10, it becomes difficult to mold a polybenzimidazole polymer due to the increase in viscosity.

  The acidification-containing polymer in the present invention is used by mixing with the polybenzimidazole polymer in the present invention, but the ratio of the acid group-containing polymer and the acid group-containing polybenzimidazole polymer is 99.9 by mass ratio. : 0.1 to 30:70 is required, 99: 1 to 50:50 is more preferable, and 95: 5 to 70:30 is particularly preferable. When the content of the acidic group-containing polybenzimidazole is less than 0.1% by mass, the swellability at high temperature and high humidity tends to be too high as an ion conductive membrane, and when it is more than 70% by mass, the dimensional stability is increased. This is because, though good, there is a tendency that the ionic conductivity is lowered.

  The resin composition containing the sulfonic acid group-containing polymer and the polybenzimidazole polymer in the present invention may be prepared by mixing the polybenzimidazole polymer and the sulfonic acid group-containing polymer by a known method, for example, a polymerization solution, It can be obtained by mixing the isolated polymer and the redissolved polymer solution. The mixed resin composition can be formed into a fiber or a film by any method such as extrusion, spinning, rolling, and casting. Among these molding processes, it is preferable to mold from a solution dissolved in a suitable solvent. Soluble solvents include aprotic polar solvents such as N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphonamide, polyphosphoric acid, methanesulfonic acid, sulfuric acid, A suitable acid can be selected from strong acids such as trifluoroacetic acid, but is not limited thereto. Among these, it is particularly preferable to mold from an organic solvent system. A plurality of these solvents may be used as a mixture within a possible range. As a means for improving the solubility, a solvent obtained by adding a Lewis acid such as lithium bromide, lithium chloride, or aluminum chloride to an organic solvent may be used. The polymer concentration in the solution is preferably in the range of 0.1 to 50% by mass. If it is too low, the moldability tends to deteriorate, and if it is too high, the workability may deteriorate.

  In the case of a blend resin composition composed of an acidic group-containing polymer and a basic polymer such as polybenzimidazole, which has been reported so far, precipitation often occurs during the dissolution of the polymer due to an acid-base interaction between the polymers. Therefore, both polymers are dissolved in the same solvent by adding an amine compound or the like to make the acidic group polymer into a salt. For this reason, for example, after forming into an ion conductive membrane, in order to provide proton conductivity, the process of acid-treating and removing an amine salt was required. Since the acidic group-containing polybenzimidazole of the present invention has an acidic group in the basic polymer chain, it was added as disclosed in JP-A No. 2003-327825 and JP-A No. 2005-139318. It has the characteristic of not forming a salt with an acid group-containing polymer and precipitating. For this reason, both polymers can be uniformly dissolved in the same solvent as they are, and after forming as an ion conductive membrane, they also have the advantage of exhibiting proton conduction characteristics as they are.

  A known method can be used as a method of obtaining a molded body from a solvent solution. For example, the molded product of polybenzimidazole containing a sulfonic acid group and / or a phosphonic acid group can be obtained by removing the solvent by heating, drying under reduced pressure, or dipping in a polymer non-solvent that is miscible with a solvent that dissolves the polymer. When the solvent is an organic solvent, the solvent is preferably distilled off by heating or drying under reduced pressure. When the solvent is a strong acid, it is preferably immersed in water, methanol, acetone or the like.

  If necessary, the acid group-containing polybenzimidazole and the acid group-containing polymer in the present invention can be formed into a fiber or film by forming a resin composition in a form combined with another polymer. Examples of the polymer that can be used for the composite are polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6, nylon 66, nylon 610, and nylon 12, polymethyl methacrylate, and polymethacrylates. Acrylate resins such as polymethyl acrylate and polyacrylates, polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate, ethyl cellulose Cellulosic resins such as polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, poly -Thermosulfon such as ether sulfone, polyether ether ketone, polyether imide, polyimide, polyamide imide, polybenzoxazole, polybenzthiazole, epoxy resin, phenol resin, novolac resin, benzoxazine resin, etc. There is no particular limitation. When used as a resin composition with these polymers, the polybenzimidazole polymer and the acidic group-containing polymer of the present invention are preferably contained in an amount of 50% by mass or more and less than 100% by mass of the entire resin composition. . More preferably, it is 70 mass% or more and less than 100 mass%. When the content of the polybenzimidazole-based polymer and the acidic group-containing polymer of the present invention is less than 50% by mass of the entire resin composition, the ion conductive membrane containing this resin composition cannot obtain good ion conductivity. In addition, the unit containing an acidic group tends to be a discontinuous phase and the mobility of ions to be conducted tends to be lowered. The resin composition of the present invention can be used, for example, as necessary, for example, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a viscosity modifier, an antistatic agent, an antibacterial agent, and an antifoaming agent. In addition, various additives such as a dispersant and a polymerization inhibitor may be contained. Further, it may contain other components such as carbon particles carrying a catalyst such as Pt and Pt—Ru, and a fluororesin.

  A preferable method for molding a resin composition containing the sulfonic acid group-containing polymer in the present invention and the acidic group-containing polybenzimidazole polymer in the present invention is a casting method from a solution. The film can be obtained by removing the solvent from the cast solution as described above. The solvent is preferably dried from the viewpoint of film uniformity. Further, in order to avoid decomposition or alteration of the polymer or solvent, it is preferable to dry at a temperature as low as possible under reduced pressure. As the substrate to be cast, a glass plate, a Teflon (registered trademark) plate, or the like can be used. When the viscosity of the solution is high, when the substrate or the solution is heated and cast at a high temperature, the viscosity of the solution is lowered and can be easily cast. The thickness of the solution at the time of casting is not particularly limited, but is preferably 10 to 1000 μm. If it is too thin, the shape of the film cannot be maintained, and if it is too thick, a non-uniform film can be easily formed. More preferably, it is 100-500 micrometers. As a method for controlling the cast thickness of the solution, a known method can be used. For example, the thickness can be controlled with the amount and concentration of the solution with a constant thickness using an applicator, a doctor blade, or the like, and with a cast area constant using a glass petri dish or the like. The cast solution can obtain a more uniform film by adjusting the solvent removal rate. For example, in the case of heating, the evaporation rate can be reduced by lowering the temperature in the first stage. In addition, when immersed in a non-solvent such as water, the solidification rate of the polymer can be adjusted by leaving the solution in air or an inert gas for an appropriate time. The film of the present invention can have any film thickness depending on the purpose, but is preferably as thin as possible from the viewpoint of ion conductivity. Specifically, it is preferably 200 μm or less, more preferably 50 μm or less, and most preferably 20 μm or less.

EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. Various measurements were performed as follows.
・ Solution viscosity:
The sulfonic acid group-containing polymer is dissolved in N-methylpyrrolidone at a concentration of 0.5 g / dl, and the viscosity is measured using a Ubbelohde viscometer in a constant temperature bath at 30 ° C. to obtain a logarithmic viscosity ln [ta / tb]. / C) (ta is the drop time of the sample solution, tb is the drop time of the solvent only, and c is the polymer concentration). The acidic group-containing polybenzimidazole was dissolved in concentrated sulfuric acid at a concentration of 0.5 g / dl, the viscosity was measured using an Ostwald viscometer in a thermostatic bath at 30 ° C., and the logarithmic viscosity was calculated using the same calculation formula. .
・ TGA:
Using a thermogravimetry meter (TGA-50) manufactured by Shimadzu Corporation, measurement was carried out in an argon atmosphere at a temperature rising rate of 10 ° C./min (while being kept at 150 ° C. for 30 minutes to sufficiently remove moisture).

・ Ion conductivity measurement:
A platinum wire (diameter: 0.2 mm) is pressed against the surface of a strip-shaped film sample on a self-made measuring probe (manufactured by Teflon (registered trademark)), and a constant temperature and humidity oven at 80 ° C. and 95% RH (Nagano Science Machinery Co., Ltd.) The sample was held in LH-20-01), and the impedance between the platinum wires was measured by SOLARTRON 1250 FREQUENCY RESPONSE ANALYSER. The measurement was performed while changing the distance between the electrodes, and the conductivity obtained by canceling the contact resistance between the film and the platinum wire was calculated from the gradient obtained by plotting the distance measured between the electrodes and the resistance measurement value estimated from the CC plot. Moreover, the same measurement was performed by immersing the measurement probe in ultrapure water kept at 25 ° C., and proton conductivity in water was also calculated.
Conductivity [S / cm] = 1 / film width [cm] × film thickness [cm] × resistance interelectrode gradient [Ω / cm]
・ Sulfonic acid group content:
The sample dried overnight under a nitrogen atmosphere was weighed, stirred with an aqueous sodium hydroxide solution, and then ion exchange capacity (IEC) (meq / g) was determined by back titration with an aqueous hydrochloric acid solution.

・ Methanol permeation rate:
A membrane immersed in a 5 M (mol / liter) aqueous methanol solution adjusted to 25 ° C. for 24 hours is sandwiched between H-type cells, 100 ml of 5 M aqueous methanol solution is placed on one side of the cell, and 100 ml of ultrapure water (18 MΩ · cm), and the amount of methanol diffusing into the ultrapure water through the ion exchange membrane while stirring the cells on both sides at 25 ° C. was calculated using a gas chromatograph (ion exchange membrane). The area is 2.0 cm ² ).
·Glass-transition temperature:
Using a Rheogel-E4000 manufactured by Orientec Corp., a tensile sine wave was applied to a film sample having a sample width of 5 mm and an effective sample length of 15 mm, and dynamic viscoelasticity measurement was performed at a heating rate of 2 ° C./min. The temperature at which the elastic modulus begins to decrease with increasing temperature is defined as the glass transition point.

・ Evaluation of power generation characteristics using methanol as fuel:
After adding and moistening a small amount of ultrapure water and isopropyl alcohol to Pt / Ru catalyst-supported carbon (Tanaka Kikinzoku Kogyo TEC61E54), a DuPont 20% Nafion (registered trademark) solution (product number: SE-20192) is used. The Pt / Ru catalyst-supported carbon and Nafion were added so that the mass ratio was 2.5: 1. Next, stirring was performed to prepare an anode catalyst paste. This catalyst paste is applied to a carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) serving as a gas diffusion layer by screen printing so that the amount of platinum deposited is 2 mg / cm ^2, and then carbon paper with an electrode catalyst layer for an anode. Was made. Further, after adding a small amount of ultrapure water and isopropyl alcohol to a Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo TEC10V40E) and moistening it, a DuPont 20% Nafion solution (product number: SE-20192) was added to the Pt catalyst-supporting carbon. And a Nafion mass ratio of 2.5: 1 were added and stirred to prepare a cathode catalyst paste. The catalyst paste was applied and dried on carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) subjected to water repellent treatment so that the amount of platinum deposited was 1 mg / cm ^2. Produced. By sandwiching the membrane sample between the two types of carbon paper with the electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane sample, pressurizing and heating at 160 ° C. and 8 MPa for 3 minutes by a hot press method, A membrane-electrode assembly was obtained. This joined body was incorporated into an evaluation fuel cell FC25-02SP manufactured by Electrochem, and a power generation test was performed using a fuel cell power generation tester (manufactured by Toyo Corporation). Power generation was performed at a cell temperature of 40 ° C. while supplying a 2 mol / l aqueous methanol solution (1.5 ml / min) and high-purity oxygen gas (80 ml / min) adjusted to 40 ° C. to the anode and cathode, respectively.

・ Evaluation of power generation characteristics using hydrogen as fuel:
It becomes uniform after adding commercially available 40% Pt catalyst-supporting carbon (manufactured by Tanaka Kikinzoku Kogyo TEC10V40E), a small amount of ultrapure water and isopropanol to a DuPont 20% Nafion (registered trademark) solution. To prepare a catalyst paste. This catalyst paste was uniformly applied to carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) so that the amount of platinum deposited was 0.5 mg / cm ² and dried to prepare a gas diffusion layer with an electrode catalyst layer. An ion exchange membrane is sandwiched between the gas diffusion layers with an electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane, and the membrane is pressed and heated at 160 ° C. and 8 MPa for 3 minutes by a hot press method. -It was set as the electrode assembly. The joined body was assembled in an evaluation fuel cell FC25-02SP manufactured by Electrochem, and hydrogen and air humidified at 75 ° C. were supplied to the anode and the cathode at a cell temperature of 80 ° C., and the power generation characteristics were evaluated.

(Synthesis Example 1)
3,3′-disulfo-4,4′-dichlorodiphenylsulfone disodium salt (abbreviation: S-DCDPS) 10.2452 g (0.020855 mole), dichlorobenzonitrile (abbreviation: DCBN) 9.2246 g (0.053628 mole) , Terminal hydroxyl group-containing phenylene ether oligomer (abbreviation: DPE, SPECIANOL DPE-PL, lot C001, manufactured by Dainippon Ink Co., Ltd.) 20.4777 g (0.03724 mole), 4,4 ′ dihydroxydiphenyl ether 7.5307 g (0.03724 mole), 11.8385 g (0.08566 mole) of potassium carbonate was weighed into a 200 ml four-necked flask and flushed with nitrogen. 140 ml of N-methyl-2-pyrrolidone was added, and the mixture was heated and stirred, and the reaction temperature was raised to 195 to 200 ° C. to react for 16 hours. After allowing to cool, the polymerization solution was poured into water to precipitate the polymer into strands. The obtained polymer was dipped in fresh water for one day and then dried. The logarithmic viscosity of the obtained polymer was 1.05.
20 g of the obtained polymer was dissolved in 80 ml of NMP, cast to a thickness of about 500 μm on a glass plate on a hot plate, NMP was distilled off until a film was formed, and then immersed in water overnight. The obtained film was immersed in dilute sulfuric acid (6 ml of concentrated sulfuric acid, 300 ml of water) for 1 day to remove the salt, and then immersed in pure water twice for 1 hour to remove the acid component and dried. did. When the ionic conductivity of this film was measured, it showed a value of 0.05 S / cm at 80 ° C. and 95% RH and 0.020 S / cm in 25 ° C. water. The weight loss starting temperature (measured based on the sample weight at 200 ° C.) by thermogravimetry of this film was 297 ° C., and the 3% weight reduction temperature was 362 ° C. The IEC determined by titration was 0.92 meq / g. The methanol permeability coefficient was 0.052 μmol / m · sec. The glass transition temperature measured by dynamic viscoelasticity was 153 ° C.

(Synthesis Example 2)
S-DCDPS 11.0125 g (0.022417 mole), DCBN 4.0134 g (0.02333 mole), DPE (Dai Nippon Ink & Co., Ltd. SPECIANOL DPE-PL, lot C001) 12.5779 g (0.022875 mole), 4,4 ′ dihydroxydiphenyl ether 4.6255 g (0.022875 mole) and 7.2715 g (0.05261 mole) of potassium carbonate were weighed into a 200 ml four-necked flask and flushed with nitrogen. 100 ml of N-methyl-2-pyrrolidone (abbreviation: NMP) was added, heated and stirred, and the reaction temperature was raised to 195-200 ° C. and reacted for 5 hours. After allowing to cool, the polymerization solution was poured into water to precipitate the polymer into strands. The obtained polymer was dipped in fresh water for one day and then dried. The logarithmic viscosity of the obtained polymer was 1.11.
20 g of the obtained polymer was dissolved in 80 ml of NMP, cast to a thickness of about 500 μm on a glass plate on a hot plate, NMP was distilled off until a film was formed, and then immersed in water overnight. The obtained film was immersed in dilute sulfuric acid (6 ml of concentrated sulfuric acid, 300 ml of water) for 1 day to remove the salt, and then immersed in pure water twice for 1 hour to remove the acid component and dried. did. When the ion conductivity of this film was measured, it showed a value of 0.19 S / cm at 80 ° C. and 95% RH and 0.091 S / cm in 25 ° C. water. The weight loss starting temperature (measured based on the sample weight at 200 ° C.) by thermogravimetry of this film was 284 ° C., and the 3% weight reduction temperature was 346 ° C. The IEC determined by titration was 1.52 meq / g. The methanol permeability coefficient was 0.22 μmol / m · sec. The glass transition temperature measured by dynamic viscoelasticity was 162 ° C.

(Synthesis Example 3)
S-DCDPS 7.1016 g (0.01446 mole), DCBN 6.3941 g (0.03717 mole), DPE (Dai Nippon Ink & Co., SPECIANOL DPE-PL, lot C001) 14.7491 g (0.025815 mole), 4,4′-biphenol 4. 8069 g (0.025815 mole) and potassium carbonate 8.2060g (0.059373 mole) were weighed into a 200 ml four-necked flask and flushed with nitrogen. 100 ml of N-methyl-2-pyrrolidone was added, the mixture was stirred with heating, the reaction temperature was raised to 195-200 ° C., and the mixture was reacted for 15 hours. After allowing to cool, the polymerization solution was poured into water to precipitate the polymer into strands. The obtained polymer was dipped in fresh water for one day and then dried. The logarithmic viscosity of the obtained polymer was 0.94.
20 g of the obtained polymer was dissolved in 80 ml of NMP, cast to a thickness of about 500 μm on a glass plate on a hot plate, NMP was distilled off until a film was formed, and then immersed in water overnight. The obtained film was immersed in dilute sulfuric acid (6 ml of concentrated sulfuric acid, 300 ml of water) for 1 day to remove the salt, and then immersed in pure water twice for 1 hour to remove the acid component and dried. did. When the ionic conductivity of this film was measured, it was 0.08 S / cm at 80 ° C. and 95% RH, and 0.042 S / cm in 25 ° C. water. The IEC determined by titration was 0.95 meq / g. The methanol permeability coefficient was 0.048 μmol / m · sec.

(Synthesis Example 4)
S-DCDPS 8.3450 g (0.016987 mole), 4,4′-dichlorodiphenylsulfone 9.9040 g (0.03449 mole), DPE (Dai Nippon Ink Co., Ltd. SPECIANOL DPE-PL, lot C001) 14.7056 g (0.025738 mole) ), 4,4′dihydroxydiphenyl ether (5.2045 g, 0.025738 mole) and 8.1817 g (0.05920 mole) of potassium carbonate were weighed into a 200 ml four-necked flask and flushed with nitrogen. 115 ml of N-methyl-2-pyrrolidone was added, and the mixture was heated and stirred, and the reaction temperature was raised to 195 to 200 ° C. and reacted for 19 hours. After allowing to cool, the polymerization solution was poured into water to precipitate the polymer into strands. The obtained polymer was dipped in fresh water for one day and then dried. The logarithmic viscosity of the obtained polymer was 0.99.
20 g of the obtained polymer was dissolved in 80 ml of NMP, cast to a thickness of about 500 μm on a glass plate on a hot plate, NMP was distilled off until a film was formed, and then immersed in water overnight. The obtained film was immersed in dilute sulfuric acid (6 ml of concentrated sulfuric acid, 300 ml of water) for 1 day to remove the salt, and then immersed in pure water twice for 1 hour to remove the acid component and dried. did. When the ionic conductivity of this film was measured, it was 0.09 S / cm at 80 ° C. and 95% RH, and 0.039 S / cm in 25 ° C. water. The IEC determined by titration was 0.93 meq / g. The methanol permeability coefficient was 0.14 μmol / m · sec.

(Synthesis Example 5)
S-DCDPS 6.9499 g (0.01415 mole), DCBN 9.7340 g 0.05659 mole), 4,4′-biphenol (abbreviation: BP) 6.5860 g (0.03537 mole), bis (4-hydroxyphenyl) sulfide (abbreviation: BPS) ) 7.7199 g (0.03537 mole), potassium carbonate 10.75542 g (0.07782 mole), and 7 g of dried molecular sieve 3-A were weighed into a 200 ml four-necked flask and flushed with nitrogen. After adding 80 ml of NMP and stirring at 150 ° C. for 30 minutes, the reaction temperature was increased to 195-200 ° C., and the reaction was continued with the aim of sufficiently increasing the viscosity of the system (about 10 hours). After standing to cool, the precipitated molecular sieve was removed and the mixture was precipitated in water as a strand. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the obtained polymer was 1.21 dl / g. 7 g of the obtained polymer was dissolved in 28 g of NMP, cast on a glass plate on a hot plate to a thickness of about 400 μm, and heated at 80 ° C. for 0.5 hour, 120 ° C. for 0.5 hour, and 150 ° C. for 0.5 hour. Then, it was dried in an oven at 150 ° C. in a nitrogen atmosphere for 1 hour, and the film was peeled from the glass plate. The obtained film was immersed in pure water at room temperature for 1 day, and then immersed in an aqueous sulfuric acid solution having a concentration of 2 mol / liter for 2 hours. Thereafter, the film was washed with pure water until the washing water became neutral, and allowed to stand in the air and dried to obtain an ion exchange membrane. When the ion conductivity of this film was measured, it showed a value of 0.019 S / cm in 25 ° C. water. The IEC determined by titration was 1.07 meq / g. The methanol permeability coefficient was 0.051 μmol / m · sec.

(Synthesis Example 6)
Synthetic Example 5 except that 4.6054 g (18.39 mmol) of 4,4′-thiobisbenzenethiol (abbreviation: TBT) was used instead of BPS, and the amount of BP was changed to 9.7472 g (52.35 mmol). In the same manner, an ion exchange membrane was prepared and evaluated. The ionic conductivity in water at 25 ° C. was 0.023 S / cm. The IEC determined by titration was 1.02 meq / g. The methanol permeability coefficient was 0.047 μmol / m · sec.

(Synthesis Example 7)
S-DCDPS 6.9499 g (0.03113 mole), DCBN 9.7340 g (0.03961 mole), BP 6.5860 g (0.06367 mole), BPS 7.7199 g (0.00707 mole), potassium carbonate 10.75542 g (0.07782 mole), dried 7 g of the molecular sieve 3-A was weighed into a 200 ml four-necked flask and flushed with nitrogen. After adding 80 ml of NMP and stirring at 150 ° C. for 30 minutes, the reaction temperature was raised to 195-200 ° C., and the reaction was continued with the aim of sufficiently increasing the viscosity of the system (about 14 hours). After standing to cool, the precipitated molecular sieve was removed and the mixture was precipitated in water as a strand. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the obtained polymer was 0.97 dl / g. 7 g of the obtained polymer was dissolved in 28 g of NMP, cast on a glass plate on a hot plate to a thickness of about 400 μm, and heated at 80 ° C. for 0.5 hour, 120 ° C. for 0.5 hour, and 150 ° C. for 0.5 hour. Then, it was dried in an oven at 150 ° C. in a nitrogen atmosphere for 1 hour, and the film was peeled from the glass plate. The obtained film was immersed in pure water at room temperature for 1 day, and then immersed in an aqueous sulfuric acid solution having a concentration of 2 mol / liter for 2 hours. Thereafter, the film was washed with pure water until the washing water became neutral, and allowed to stand in the air and dried to obtain an ion exchange membrane. When the ion conductivity of this film was measured, it showed a value of 0.26 S / cm at 80 ° C. and 95% RH. The IEC determined by titration was 2.00 meq / g.

(Synthesis Example 8)
3,3 ′, 4,4′-tetraaminodiphenylsulfone (abbreviation: TAS) 1.500 g (5.389 × 10 ⁻³ mole), monosodium 2,5-dicarboxybenzenesulfonate (abbreviation: STA, purity) 99%) 1.445 g (5.389 × 10 ⁻³ mole), polyphosphoric acid (phosphorus pentoxide content 75%) 20.48 g, and phosphorus pentoxide 16.41 g are weighed in a polymerization vessel. Flow nitrogen and raise the temperature to 100 ° C while stirring gently on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. and polymerized for 4 hours. After completion of the polymerization, the mixture was allowed to cool, water was added, the polymer was taken out, and washing with water was repeated until the pH test paper became neutral using a household mixer. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the obtained polymer was 1.92.

(Synthesis Example 9)
TAS1.830 g (6.575 × 10 ⁻³ mole), 3,5-dicarboxyphenylphosphonic acid 1.084 g (abbreviation: DCP) 4.405 × 10 ⁻³ mole), terephthalic acid 0.360 g (2.170) × 10 ⁻³ mole), 20.5 g of polyphosphoric acid (phosphorus pentoxide content: 75%), and 16.5 g of phosphorus pentoxide are weighed in a polymerization vessel. Flow nitrogen and raise the temperature to 100 ° C while stirring gently on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. and polymerized for 7 hours. After completion of the polymerization, the mixture was allowed to cool, water was added, the polymer was taken out, and washing with water was repeated until the pH test paper became neutral using a household mixer. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the polymer measured using sulfuric acid was 1.18.

(Synthesis Example 10)
^{TAS1.830g (6.575 × 10 -3 mole)} , STA ( purity ^{99%) 0.529g (1.973 × 10} -3 mole), DCP ( purity 98%) 1.133g (4.602 × 10 - ³ moles), 24.98 g of polyphosphoric acid (phosphorus pentoxide content 75%) and 20.02 g of phosphorus pentoxide are weighed into a polymerization vessel. Flow nitrogen and raise the temperature to 100 ° C while stirring gently on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. and polymerized for 5 hours. After completion of the polymerization, the mixture was allowed to cool, water was added, the polymer was taken out, and washing with water was repeated until the pH test paper became neutral using a household mixer. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the obtained polymer was 1.14.

(Synthesis Example 11)
S-DCDPS 5.2335 g (0.01065 mole), DCBN 2.3323 g (0.035559 mole), BP 4.5086 g (0.02421 mole), potassium carbonate 3.8484 g (0.02784 mole), 100 ml of molecular sieve 2.61 g The flask was weighed and flushed with nitrogen. After adding 35 ml of NMP and stirring at 150 ° C. for 1 hour, the reaction was continued by raising the reaction temperature to 195 to 200 ° C. and sufficiently increasing the viscosity of the system (about 5 hours). After standing to cool, the precipitated molecular sieve was removed and the mixture was precipitated in water as a strand. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the obtained polymer was 1.27.
1 g of the obtained polymer was dissolved in 5 ml of NMP, cast on a glass plate on a hot plate to a thickness of about 200 μm, NMP was distilled off until a film was formed, and then immersed in water overnight. The obtained film was treated with boiling water in dilute sulfuric acid (concentrated sulfuric acid 6 ml, water 300 ml) for 1 hour to remove the salt, and then boiled with pure water for 1 hour to remove the acid component. When the ionic conductivity of this film was measured, it showed a value of 0.17 S / cm at 80 ° C. and 95% RH. The 3% weight loss temperature (measured based on the sample weight at 200 ° C.) by thermogravimetry of this film was 392 ° C.

(Synthesis Example 12)
In Synthesis Example 10, polybenzimidazole was synthesized using only terephthalic acid as a dicarboxylic acid component without using STA. The logarithmic viscosity of the obtained polymer was 1.95.

(Example 1)
20 mg of the polymer prepared in Synthesis Example 8 was dissolved in 0.5 ml of NMP by heating to 170 ° C. on an oil bath, and 180 mg of the polymer prepared in Synthesis Example 1 was dissolved in 2 ml of NMP at 50 ° C. Those were mixed at room temperature to obtain a homogeneous solution. This solution was cast on a glass plate to a thickness of about 200 μm on a hot plate to evaporate NMP. The film was peeled off from the glass plate and immersed in water at 80 ° C. for 1 hour to prepare an ion conductivity measurement film. When the ionic conductivity of this film was measured, it showed a value of 0.04 S / cm at 80 ° C. and 95% RH and 0.018 S / cm in water at 25 ° C. The methanol permeability coefficient was 0.047 μmol / m · sec. When the membrane electrode assembly was produced according to the power generation evaluation procedure using methanol as a fuel for this film, a good assembly with sufficient adhesion was obtained.
(Example 2)
A blend film was produced and evaluated in the same manner as in Example 1 except that the polymer produced in Synthesis Examples 2 to 7 was used instead of the polymer produced in Synthesis Example 1. The results are shown in Table 1.

(Example 3)
A blend film was produced and evaluated in the same manner as in Example 1 except that the polymer produced in Synthesis Example 9 was used instead of the polymer produced in Synthesis Example 8. The results are shown in Table 1.
Example 4
A blend film was produced and evaluated in the same manner as in Example 3 except that the polymer produced in Synthesis Examples 2 to 7 was used instead of the polymer produced in Synthesis Example 1. The results are shown in Table 1.
(Example 5)
A blend film was produced and evaluated in the same manner as in Example 1 except that the polymer produced in Synthesis Example 10 was used instead of the polymer produced in Synthesis Example 8. The results are shown in Table 1.
(Example 6)
A blend film was produced and evaluated in the same manner as in Example 5 except that the polymer produced in Synthesis Examples 2 to 7 was used instead of the polymer produced in Synthesis Example 1. The results are shown in Table 1.

(Example 7)
A blend film was prepared in the same manner as in Example 1 except that 60 mg of the polymer prepared in Synthesis Example 8 was dissolved in 1.5 ml of NMP and 140 mg of the polymer prepared in Synthesis Example 1 was dissolved in 1.5 ml of NMP. evaluated. When the ionic conductivity of this film was measured, it showed a value of 0.03 S / cm at 80 ° C. and 95% RH and 0.014 S / cm in water at 25 ° C. The methanol permeability coefficient was 0.038 μmol / m · sec. When a membrane / electrode assembly was produced according to the power generation evaluation procedure using this film as a fuel for methanol, a good assembly having sufficient adhesion was obtained.

(Example 8)
A blend film was prepared in the same manner as in Example 1 except that 100 mg of the polymer prepared in Synthesis Example 8 was dissolved in 2.5 ml of NMP, and 100 mg of the polymer prepared in Synthesis Example 1 was dissolved in 1.0 ml of NMP. evaluated. When the ionic conductivity of this film was measured, it showed a value of 0.15 S / cm at 80 ° C. and 95% RH and 0.055 S / cm in water at 25 ° C. The methanol permeability coefficient was 0.098 μmol / m · sec. When a membrane / electrode assembly was produced according to the power generation evaluation procedure using this film as a fuel for methanol, a good assembly having sufficient adhesion was obtained.

(Comparative Example 1)
A blend film was produced in the same manner as in Example 1 except that the polymer produced in Synthesis Example 11 was used instead of the polymer produced in Synthesis Example 1. When a membrane / electrode assembly was produced in accordance with the power generation evaluation procedure using methanol as a fuel for this film, the adhesion was not sufficient and a membrane / electrode assembly for evaluation could not be produced.

(Comparative Example 2)
An attempt was made to produce a blend film in the same manner as in Example 1 except that the polymer produced in Synthesis Example 12 was used instead of the polymer produced in Synthesis Example 8, but when the polymer solution was mixed, the solution was turbid and good. Film formation could not be performed.

(Example 11)
When the film produced in Example 1 was used for power generation evaluation using methanol as a fuel, a favorable power generation characteristic of 0.33 V at a current density of 100 mA was obtained.
Example 12
When the power generation performance evaluation using hydrogen as a fuel was performed using the film produced in Example 7, a favorable power generation characteristic of 0.53 V at a current density of 1 A was obtained.

(Example 13)
In the production of the membrane electrode assembly in Example 1, the membrane electrode assembly was produced using the 10% NMP solution of the polymer produced in Synthesis Example 1 instead of the Nafion solution. It was a body.

  The resin composition of the present invention is excellent in miscibility with a solvent and can be easily formed into a film. The resulting film has excellent ion conductivity and dimensional stability under high temperature and high humidity. It is suitable as an ion exchange membrane for fuel cells and the like. Further, it can be used as a binder, an adhesive, a material for a solid polymer electrolyte membrane for a fuel cell, and the like at the time of producing a joined body of an ion exchange membrane and an electrode.

Claims (15)

A sulfonic acid group-containing polymer having a molecular structure represented by the following chemical formula (1) and having a logarithmic viscosity of 0.1 or more and a molecular structure represented by the following chemical formula (7) and having a logarithmic viscosity of 0.25 A resin composition comprising the above polybenzimidazole polymer in a mass ratio of 99.9: 0.1 to 30:70.

(Where X is hydrogen or a monovalent cation species, Y is a sulfone group or ketone group, and Ar ¹ is the following chemical formula (2), or includes both of the chemical formulas (3) and (4) simultaneously) N represents any integer of 2 or more.)

(However, if Ar ¹ is a chemical formula (2), when ^{Z 1} is an oxygen atom, n represents simultaneously contain .Ar ¹ showing the arbitrary integer of 2 or more both chemical formula (3) and (4), Z ¹ independently represents either an oxygen atom or a sulfur atom, Z ² represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, Any one of cyclohexyl groups, and when Ar ¹ contains both of the chemical formulas (3) and (4), the chemical formula (1) and the molecular structure of the following chemical formulas (5) and (6) are included at the same time. .)

(However, Ar ² and Ar ³ are divalent aromatic bond units, Z ³ and Z ⁴ are independently oxygen atoms or sulfur atoms, Z ⁵ is an oxygen atom, sulfur atom, and —C (CH _{3) 2} - group shown, one of the cyclohexyl groups - group, -C _{(CF 3) 2} - group, -CH _2.

(However, R ¹ represents a tetravalent aromatic bond unit capable of forming an imidazole ring, R ² represents a divalent aromatic bond unit, and R ¹ and R ² may be monocyclic aromatic rings. It may be a conjugate of a plurality of aromatic rings or a condensed ring, and may have a stable substituent, Z represents a sulfonic acid group and / or a phosphonic acid group, part of which has a salt structure (N represents an arbitrary integer of 2 or more, and m ¹ represents an integer of 1 to 4.) The resin composition according to claim 1, wherein the sulfonic acid group-containing polymer further comprises a molecular structure represented by the following chemical formula (8).

(However, Ar ⁴ represents a divalent aromatic bond unit, and n represents an arbitrary integer of 2 or more.) The resin composition according to claim 1 or 2, wherein Ar ^{2 to} Ar ⁴ in the molecular structure of the sulfonic acid group-containing polymer is at least one selected from the molecular structures represented by the following chemical formulas (9) to (12). object.

The resin composition according to any one of claims 1 to 3 Z ² and Z ⁵ of the sulfonic acid group-containing polymer is either a sulfur atom. The resin composition according to any one of claims 1 to 4, wherein a molar ratio of the repeating molecular structure represented by the chemical formulas (1), (5), and (6) and the other repeating molecular structures satisfy Formulas 1 to 3. object.
(Formula 1) 0.9 ≦ (n1 + n2 + n3 + n4) / (n1 + n2 + n3 + n4 + n5) ≦ 1.0
(Formula 2) 0.05 ≦ (n1 + n2) / (n1 + n2 + n3 + n4) ≦ 0.7
(Formula 3) 0.01 ≦ (n2 + n4) / (n1 + n2 + n3 + n4) ≦ 0.95
(In the above formula, n1 is the mol% of the repeating molecular structure represented by the chemical formula (1) when Ar ¹ is the chemical formula (3), and n2 is the chemical formula (1 when Ar ¹ is the chemical formula (4) (1). N3 represents the mol% of the repeating molecular structure represented by the chemical formula (5), n4 represents the mol% of the repeating molecular structure represented by the chemical formula (6), n5 Represents the mol% of other repeating molecular structures, respectively.) The sulfonic acid group-containing polymer is a terminal dihydroxy compound represented by the following chemical formula (13), and is composed of a plurality of components different from each other, and the average composition is in the range of 1 <n ≦ 10. The resin composition according to any one of claims 1 to 5, which is obtained by using the product as a part of a monomer component.

(However, n represents an integer of 0 or more.)   The resin composition according to any one of claims 1 to 6, wherein the sulfonic acid group-containing polymer has a sulfonic acid group content within a range of 0.3 to 5.0 meq / g. The polybenzimidazole-based polymer contains a binding unit represented by the structure represented by the following chemical formula (14) and chemical formula (15) as a constituent component having a molar ratio of n ¹ : (1-n ¹ ). The resin composition according to any one of claims 1 to 7.

(However, Ar represents a divalent aromatic bond unit, and X ¹ consists of —O—, —SO ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, and —OPhO—. at least one element selected from the group, Ph represents a bivalent aromatic bond unit. in addition, ^{n 1} (molar ratio), the .m ¹ satisfying the formula of 0.2 ≦ ^{n 1} ≦ 1.0 Represents an integer from 1 to 4.) The polybenzimidazole polymer has a bonding unit represented by a molecular structure represented by the following chemical formula (16) and chemical formula (17) in a molar ratio of n ² : (1-n ² ). A resin composition according to claim 1.

(However, Ar represents an aromatic bond unit, X ² is at least one selected from the group consisting of —O—, —SO ₂ —, —S—, —CH ₂ —, —OPhO—, and Ph is Represents a divalent aromatic bond unit, and n ² (molar ratio) satisfies a formula of 0.2 ≦ n ² ≦ 1.0. M ¹ represents an integer of 1 to 4. The polybenzimidazole-based polymer has a binding unit represented by the molecular structure represented by the following chemical formula (18) and chemical formula (19) in a molar ratio of n ³ : (1-n ³ ). A resin composition according to claim 1.

(However, Ar represents an aromatic bond unit, and X ³ represents —O—, —SO ₂ —, —S—, —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —. , —OPhO—, wherein Ph represents a divalent aromatic bond unit, and n ³ (molar ratio) is a formula of 0.1 ≦ n ³ ≦ 0.9. M ³ and m ⁴ represent an integer of 1 to 4.)   The ratio of a sulfonic acid group containing polymer and a polybenzimidazole-type polymer is 95: 5-70: 30 by mass ratio, The resin composition in any one of Claims 1-10.   The ion conductive film which consists of a resin composition in any one of Claims 1-11.   The composite_body | complex with which the ion conductive film and electrode of Claim 12 were joined.   A fuel cell using the composite according to claim 13 as an ion conductive membrane / electrode assembly.   The adhesive agent containing the resin composition in any one of Claims 1-11.