JP5581937B2 - Aromatic copolymer and its use - Google Patents

Description

  The present invention relates to a novel aromatic copolymer having a sulfonic acid group, a solid polymer electrolyte comprising the aromatic copolymer having a sulfonic acid group, and use thereof.

  The electrolyte is usually used in a (water) solution. However, in recent years, there is an increasing tendency to replace the electrolyte with a solid system. The first reason is, for example, the ease of processing when applied to the above-mentioned electric / electronic materials, and the second reason is the shift to light, thin, small and power saving.

  Conventionally, both inorganic compounds and organic compounds are known as proton conductive materials. Examples of inorganic compounds include uranyl phosphate, which is a hydrated compound. However, since these inorganic compounds do not have sufficient contact at the interface, there are many problems when forming a conductive layer on a substrate or electrode. Occurs.

  On the other hand, examples of organic compounds include sulfonated products of vinyl polymers such as polystyrene sulfonic acid, perfluoroalkyl sulfonic acid polymers represented by Nafion (trade name, manufactured by DuPont), and perfluoroalkyl carboxylic acid polymers. Examples include polymers belonging to so-called cation exchange resins, or organic polymers such as polymers in which a sulfonic acid group or a phosphoric acid group is introduced into a heat-resistant polymer such as polybenzimidazole or polyether ether ketone.

  When producing a fuel cell, an electrode-membrane assembly is usually obtained by sandwiching an electrolyte membrane made of the perfluoroalkylsulfonic acid polymer between both electrodes and performing a heat treatment such as hot pressing. A fluorine-based film such as this perfluoroalkyl sulfonic acid polymer has a relatively low heat deformation temperature of about 80 ° C., and can be easily joined. However, at the time of fuel cell power generation, the temperature may be 80 ° C. or higher due to the reaction heat, so that the electrolyte membrane softens and a creep phenomenon occurs, which causes a problem that both electrodes are short-circuited and power generation becomes impossible.

  In order to avoid such problems, currently the fuel cell is designed so that the thickness of the electrolyte membrane is increased to some extent or the temperature during power generation is 80 ° C. or less, but the maximum output of power generation is It will decline.

  By the way, in order to solve the problem that the mechanical property at high temperature of the electrolyte made of the perfluoroalkylsulfonic acid polymer is low due to the low thermal deformation temperature, an aromatic polymer used in engineer plastics and the like in recent years. A solid polymer electrolyte membrane using sapphire has been developed.

  For example, US Pat. No. 5,403,675 (Patent Document 1) discloses a solid polymer electrolyte made of sulfonated rigid polyphenylene. This polymer is mainly composed of a polymer obtained by polymerizing an aromatic compound comprising a phenylene chain, and this is reacted with a sulfonating agent to introduce a sulfonic acid group. The electrolyte membrane made of this polymer has a heat distortion temperature of 180 ° C. or higher and is excellent in creep resistance at high temperatures.

  However, these electrolyte membranes are greatly swelled in hot water and contracted during drying, and are still insufficient as electrolyte membranes used for solid polymer fuel cells.

US Pat. No. 5,403,675

  Under such circumstances, an aromatic copolymer having a sulfonic acid group having high proton conductivity, low swelling in hot water and small shrinkage upon drying, and proton conductivity produced from the copolymer It is desired to provide a proton conductive membrane and a polymer electrolyte having high properties.

  The present inventors have intensively studied to solve the above problems. As a result, it has been found that the above problems can be solved by an aromatic copolymer having a specific structural unit, and the present invention has been completed.

Embodiments of the present invention are shown in [1] to [8] below.
[1] A polymer segment (A) having a sulfonic acid group and a polymer segment (B) having substantially no sulfonic acid group, wherein the polymer segment (B) having substantially no sulfonic acid group has the following formula An aromatic copolymer having the structural unit represented by (1).

（上記式（１）中、Ｒ¹は、各々独立に、ハロゲン原子、炭素数１〜２０の炭化水素基、または炭素数１〜２０のハロゲン化炭化水素基であり、Ｌは、下記式（１−１）で表わされる構造単位または下記式（１−２）で表わされる構造単位であり、複数あるＬの少なくとも一つは下記式（１−１）で表わされる構造単位であり、ａは０〜４の整数、ｐは２〜２００の整数を表わす。なお、複数のＲ¹、ａおよびＬは、同一であっても異なっていてもよい。）

(In the above formula (1), each R ¹ is independently a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms. 1-1) or a structural unit represented by the following formula (1-2), at least one of the plurality of L is a structural unit represented by the following formula (1-1), and a is An integer of 0 to 4 and p represents an integer of 2 to 200. In addition, a plurality of R ¹ , a and L may be the same or different.

（上記式（１−１）中は、Ａは、各々独立に、−Ｏ−または−Ｓ−であり、Ｒ²は、各々独立に、炭素数１〜２０の炭化水素基、または炭素数１〜２０のハロゲン化炭化水素基であり、Ｗ¹は、各々独立に、ハロゲン原子であり、ｂは１〜４の整数、ｌは０〜３の整数を表わす。ただし、ｂ＋ｌは４以下である。）

(In the formula (1-1), each A is independently —O— or —S—, and each R ² is independently a hydrocarbon group having 1 to 20 carbon atoms, or 1 carbon atom. To 20 halogenated hydrocarbon groups, each W ¹ independently represents a halogen atom, b represents an integer of 1 to 4, and l represents an integer of 0 to 3. However, b + l is 4 or less. .)

（上記式（１−２）中、Ａは、各々独立に、−Ｏ−または−Ｓ−であり、Ｄは、直接結合、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_i−（ｉは１〜１０の整数である）、−（ＣＨ₂）_j−（ｊは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基またはハロゲン化炭化水素基を示す）、シクロヘキシリデン基およびフルオレニリデン基からなる群より選ばれた少なくとも１種の構造を表わし、Ｒ³及びＲ⁴は、各々独立に、炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基であり、Ｗ²及びＷ³は、各々独立に、ハロゲン原子であり、ｃ及びｄは０〜４の整数、ｍ及びｎは０〜４の整数、ｑは０〜４の整数を表わす。ただし、ｑ＝０のとき、ｄは０である。また、ｃ＋ｍおよびｄ＋ｎは４以下である。）

(In the formula (1-2), A is independently, -O- or -S-, D is a direct bond, -O -, - S -, - CO -, - SO 2 -, -SO -, - CONH -, - COO -, - (CF 2) i - (i is an integer of 1 to _{10), - (CH 2) j} - (j is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), at least one structure selected from the group consisting of a cyclohexylidene group and a fluorenylidene group R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms, and W ² and W ³ are each independently A halogen atom, c and d are integers of 0 to 4, m and n are integers of 0 to 4, and q is an integer of 0 to 4, provided that When q = 0, d is 0. Also, c + m and d + n are 4 or less.)

[2] The number average molecular weight in terms of polystyrene of the precursor represented by the following formula (1 ′) for deriving the polymer segment (B) having no sulfonic acid group is 1,000 to 50,000. Aromatic copolymer.

（上記式（１’）中、Ｒ¹、Ｌ、ａ、ｐは式（１）と同じであり、Ｚ¹はハロゲン原子、ニトロ基、−ＳＯ₂ＣＨ₃および−ＳＯ₂ＣＦ₃から選ばれる原子または基を示す。

(In the above formula (1 ′), R ¹ , L, a and p are the same as in formula (1), and Z ¹ is selected from a halogen atom, a nitro group, —SO ₂ CH ₃ and —SO ₂ CF _3. Indicates an atom or group.

[3] The aromatic copolymer of [1] or [2], wherein p is 2 to 150 in the above formula (1).
[4] The structural unit represented by the formula (1-1) and the structural unit represented by the formula (1-2) have a molar ratio (1-1) :( 1-2) of 100: 0 to 50:50. The aromatic copolymer of [1] to [3], which is contained at a ratio of
[5] The structural unit represented by the above formula (1-1) is a molar ratio (1-3) of the structural unit represented by the following formula (1-3) and the structural unit represented by the following formula (1-4). : The aromatic copolymer of [1]-[4] which is contained in the ratio of 10: 90-90: 10 in (1-4).

（上記式中、Ｒ²、Ａ、Ｗ¹、ｌは上記式（１−１）と同義であり、ｅは１または３を表わす。）

(In the above formula, R ² , A, W ¹ , and l have the same meanings as in the above formula (1-1), and e represents 1 or 3)

（上記式中、Ｒ²、Ａ、Ｗ¹、ｌは上記式（１−１）と同義であり、ｆは２または４を表わす。）
［６］スルホン酸基を有するポリマーセグメント（Ａ）が下記式（３）で表される構造単位を有する［１］〜［４］の芳香族系共重合体。

(In the above formula, R ² , A, W ¹ , and l have the same meanings as in the above formula (1-1), and f represents 2 or 4).
[6] The aromatic copolymer of [1] to [4], wherein the polymer segment (A) having a sulfonic acid group has a structural unit represented by the following formula (3).

（上記式中、Ａｒ¹¹、Ａｒ¹²、Ａｒ¹³は、それぞれ独立に、フッ素原子で置換されていてもよい、ベンゼン環、縮合芳香環、含窒素複素環からなる群より選ばれる少なくとも１種の構造を有する２価の基を示す。Ｙは、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_u−（ｕは１〜１０の整数である）、−Ｃ（ＣＦ₃）₂−、または直接結合を示す。Ｚは、−Ｏ−、−Ｓ−、直接結合、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、または−Ｃ（ＣＨ₃）₂−を示す。

(In the above formula, Ar ¹¹ , Ar ¹² , and Ar ¹³ are each independently at least one selected from the group consisting of a benzene ring, a condensed aromatic ring, and a nitrogen-containing heterocyclic ring, which may be substituted with a fluorine atom. Y represents a divalent group having a structure, Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _u — (u is an integer of 1 to 10; Z) represents —O—, —S—, direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ), or —C (CF ₃ ) ₂ — or a direct bond. _l - (l is an integer of 1 to 10), or -C (CH _{3) 2} - shows a.

R ²² represents a direct bond, —O (CH ₂ ) _p —, —O (CF ₂ ) _p —, — (CH ₂ ) _p — or — (CF ₂ ) _p — (p is 1 to 12) Indicates an integer). R ²³ and R ²⁴ each independently represent a hydrogen atom, an alkali metal atom, an aliphatic hydrocarbon group, an alicyclic group, or a heterocyclic group containing oxygen. However, at least one of all R ²³ and R ²⁴ included in the above formula is a hydrogen atom.

x ¹ is an integer of 0 to 4, x ² is an integer of 1 to 5, a is an integer of 0 to 1, and b is an integer of 0 to 3. )
[7] A polymer electrolyte comprising the aromatic copolymer of [1] to [6].
[8] A proton conducting membrane comprising the aromatic copolymer of [1] to [7].

  Since the aromatic copolymer having a sulfonic acid group according to the present invention has a specific structural unit, swelling in hot water and shrinkage during drying are small. Therefore, it is possible to introduce a sulfonic acid group at a high concentration, and it is possible to obtain a solid polymer electrolyte and a proton conductive membrane having high proton conductivity, high dimensional stability, and high mechanical strength.

  Further, since the swelling in hot water and the shrinkage at the time of drying are small, the heat resistance and durability are high, so the aromatic copolymer having a sulfonic acid group according to the present invention is a proton conductive membrane for a fuel cell. And can be suitably used as an electrolyte.

Hereinafter, the aromatic copolymer, solid polymer electrolyte, and proton conductive membrane according to the present invention will be described in detail.
[Aromatic copolymer]
The aromatic copolymer of the present invention has a polymer segment (A) having a sulfonic acid group and a polymer segment (B) having substantially no sulfonic acid group.
[Polymer segment (A) having a sulfonic acid group]
The polymer segment (A) having a sulfonic acid group is not particularly limited as long as it contains a structural unit having a sulfonic acid group. However, the structural unit has a sulfonic acid group as a side chain directly on an aromatic ring. Is preferred.

  As the structural unit having a sulfonic acid group, a structural unit represented by the following formula (3) is preferable.

上記式（３−１）中、Ａｒ¹¹、Ａｒ¹²、Ａｒ¹³は、それぞれ独立に、フッ素原子で置換されていてもよい、ベンゼン環、縮合芳香環、含窒素複素環からなる群より選ばれた少なくとも１種の構造を有する２価の基を示す。

In the above formula (3-1), Ar ¹¹ , Ar ¹² and Ar ¹³ are each independently selected from the group consisting of a benzene ring, a condensed aromatic ring and a nitrogen-containing heterocyclic ring which may be substituted with a fluorine atom. And a divalent group having at least one structure.

Y represents —CO—, —CONH—, —COO—, —SO ₂ —, —SO—, — (CF ₂ ) _u — (u is an integer of 1 to 10), —C (CF ₃ ) _2. -Or indicates direct binding.
Z is —O—, —S—, direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ) ₁ — (l is an integer of 1 to 10), or C (CH ₃ ) Indicates ₂₋ .

R ²² represents a direct bond, —O (CH ₂ ) _p —, —O (CF ₂ ) _p —, — (CH ₂ ) _p — or (CF ₂ ) _p — (p is an integer of 1 to 12) Showing).
R ²³ and R ²⁴ each independently represent a hydrogen atom, an alkali metal atom or an aliphatic hydrocarbon group. However, at least one of all R ²³ and R ²⁴ included in the above formula is a hydrogen atom.

x ¹ is an integer of 0 to 4, x ² is an integer of 1 to 5, a is an integer of 0 to 1, and b is an integer of 0 to 3.
The structural unit having a sulfonic acid group is preferably composed of a repeating unit represented by the following formula (3-1).

上記式（３−１−１）中、Ａｒ¹¹、Ａｒ¹²、Ａｒ¹³、Ｙ、Ｚ、Ｒ²²、Ｒ²³、Ｒ²⁴は、式（３−１）と同義である。

In said formula (3-1-1), Ar < ¹¹ >, Ar < ¹² >, Ar < ¹³ >, Y, Z, R < ²² >, R <^23> , R < ²⁴ > is synonymous with Formula (3-1).

x ¹ is an integer of 0 to 4, x ² is an integer of 1 to 5, a is an integer of 0 to 1, and b1 and b2 are integers of 0 to 3.
The repeating unit represented by the above formula (3) or (3-1) is preferably a structure represented by the following formula (3-2) or the following formula (3-3).

式（３−２）中、Ｙは−ＣＯ−、−ＳＯ₂−、−ＳＯ−、直接結合、−（ＣＦ₂）_u−（ｕは１〜１０の整数である）、−Ｃ（ＣＦ₃）₂−からなる群より選ばれた少なくとも１種の構造を示す。

In formula (3-2), Y represents —CO—, —SO ₂ —, —SO—, a direct bond, — (CF ₂ ) _u — (u is an integer of 1 to 10), —C (CF _{3 2} ) At least one structure selected from the group consisting of _2- .

Z is a direct bond, or — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, —S—, —CO—, —SO ₂ —. At least one structure selected from the group consisting of: Ar represents a substituent represented by —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H; The aromatic group which has. p shows the integer of 1-12, m shows the integer of 0-3, n shows the integer of 0-3, k shows the integer of 1-4. Among the single lines at the end of the structural unit, those not having a substituent displayed on one side mean connection with the adjacent structural unit. When m and n are 2 or more, the plurality of Z and k may be the same or different, and the bonding position is not particularly limited. Examples of the aromatic group include a phenyl group and a naphthyl group.

  Specific examples of the structural unit having a sulfonic acid group include the following.

本発明では、スルホン酸基の代わりに、ないしスルホン酸基とともに、ホスホン酸基を有する構造単位を含むものであってもよい。

In the present invention, a structural unit having a phosphonic acid group may be included instead of the sulfonic acid group or together with the sulfonic acid group.

上記式（３−３）中、Ｒ¹は、各々独立に、ハロゲン原子、炭素数１〜２０の１価の炭化水素基、または炭素数１〜２０の１価のハロゲン化炭化水素基であり、ａは０〜３の整数、ｋは１〜４−ａの整数を表わす。なお、複数のＲ¹は、同一であっても異なっていてもよい。

In the above formula (3-3), each R ¹ is independently a halogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms. , A represents an integer of 0 to 3, and k represents an integer of 1 to 4-a. The plurality of R ¹ may be the same or different.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms in R ¹ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, tetramethylbutyl group, amyl group, C1-C20 alkyl groups such as pentyl and hexyl groups; C3-C20 cycloalkyl groups such as cyclopentyl and cyclohexyl groups; C6-C20 aromatics such as phenyl, naphthyl and biphenyl groups Group hydrocarbon group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group and allyl group.

Examples of the monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms in R ¹ include a halogenated alkyl group having 1 to 20 carbon atoms, a halogenated cycloalkyl group having 3 to 20 carbon atoms, and 6 to 20 carbon atoms. And halogenated aromatic hydrocarbon groups. Examples of the halogenated alkyl group include a trichloromethyl group, a trifluoromethyl group, a tribromomethyl group, a pentachloroethyl group, a pentafluoroethyl group, and a pentabromoethyl group; and the halogenated aromatic hydrocarbon group. Examples thereof include a chlorophenyl group and a chloronaphthyl group.

a is preferably 0 or 1, and more preferably 0.
k is preferably 1.
In addition, the aromatic copolymer of the present invention desirably contains at least two continuous units when the structural unit represented above is included from the viewpoint of mechanical strength and hot water resistance of the obtained electrolyte membrane, It is more desirable that at least three are continuous, and it is even more desirable that at least five are continuous.

In addition, the swelling at the time of hot water immersion and the shrinkage at the time of drying can be highly suppressed by including the structural unit represented by Formula (3-1).
[Polymer segment substantially free of sulfonic acid group (B)]
In the copolymer according to the present invention, the polymer segment (B) having substantially no sulfonic acid group has a structural unit represented by the following formula (1).

上記式（１）中、Ｒ¹は、各々独立に、ハロゲン原子、炭素数１〜２０の炭化水素基、または炭素数１〜２０のハロゲン化炭化水素基であり、Ｌは、後記する式（１−１）で表わされる構造単位または式（１−２）で表わされる構造単位である。

In the above formula (1), each R ¹ is independently a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms, and L is a formula ( The structural unit represented by 1-1) or the structural unit represented by Formula (1-2).

Specific examples of R ¹ include alkyl groups such as a methyl group, a methyl group, an ethyl group, and a propyl group, aryl groups such as a phenyl group, a toluyl group, and a naphthyl group, and those in which these hydrogens are substituted with a halogen. .

a shows the integer of 0-4 each independently. p represents an integer of 2 to 200, preferably 2 to 150. A plurality of R ¹ , a and L may be the same or different.
At least one of the plurality of L is a structural unit represented by the following formula (1-1).

  By including such a structural unit represented by the formula (1-1), the movement of the molecular chain segment of the polymer main chain can be suppressed, and in the hot water of the aromatic copolymer having a sulfonic acid group Swelling and shrinkage during drying can be reduced.

上記式（１−１）中は、Ａは、各々独立に、−Ｏ−または−Ｓ−であり、Ｒ²は、各々独立に、炭素数１〜２０の炭化水素基、または炭素数１〜２０のハロゲン化炭化水素基である。

In the above formula (1-1), each A is independently -O- or -S-, and each R ² is independently a hydrocarbon group having 1 to 20 carbon atoms, or 1 to carbon atoms. 20 halogenated hydrocarbon groups.

Specific examples of R ² include methyl groups, methyl groups, ethyl groups, propyl groups, tert-butyl groups, alkyl groups such as 1,1,3,3-tetramethylbutyl groups, phenyl groups, toluyl groups, and naphthyl groups. And those in which these hydrogens are substituted with halogens.

  Of these, branched alkyl groups such as a tert-butyl group and 1,1,3,3-tetramethylbutyl group are preferred in the present invention because they can further suppress swelling during hot water immersion and shrinkage during drying.

Moreover, when there are a plurality of structural units represented by (1-1), these structural units may be the same or different.
W ¹ each independently represents a halogen atom, b represents an integer of 1 to 4, and l represents an integer of 0 to 3. However, b + 1 is 4 or less.

  The structural unit represented by the above formula (1-1) preferably includes a structural unit represented by the following formula (1-3) and a structural unit represented by the following formula (1-4). At this time, the structural units represented by the formulas (1-3) and (1-4) in the total moles of the structural unit represented by the formula (1-1) are converted to a molar ratio (1-3) :( 1 -4), 10:90 to 90:10, preferably 20:80 to 80:20.

上記式（１−３）中、Ｒ²、Ａ、Ｗ¹、ｌは上記式（１−１）と同義であり、ｅは１または３を表わす。

In said formula (1-3), R < ² >, A, W < ¹ >, l is synonymous with said formula (1-1), and e represents 1 or 3.

上記式（１−４）中、Ｒ²、Ａ、Ｗ¹、ｌは上記式（１−１）と同義であり、ｆは２または４を表わす。

In said formula (1-4), R < ² >, A, W < ¹ >, l is synonymous with the said formula (1-1), f represents 2 or 4.

  By containing both of the structural units represented by the formulas (1-3) and (1-4), swelling and drying in hot water without impairing polymer productivity and film-forming properties. A film having a small shrinkage can be obtained.

  Examples of the structural unit that can constitute L include a structural unit represented by the following formula (1-2).

上記式（１−２）中、Ａは、各々独立に、−Ｏ−または−Ｓ−であり、Ｄは、直接結合、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_i−（ｉは１〜１０の整数である）、−（ＣＨ₂）_j−（ｊは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基またはハロゲン化炭化水素基を示す）、シクロヘキシリデン基およびフルオレニリデン基からなる群より選ばれた少なくとも１種の構造を表わし、Ｒ³及びＲ⁴は、各々独立に、炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基であり、Ｗ²及びＷ³は、各々独立に、ハロゲン原子であり、ｃ及びｄは０〜４の整数、ｍ及びｎは０〜４の整数、ｑは０〜４の整数を表わす。ただし、ｑ＝０のとき、ｄは０である。また、ｃ＋ｍおよびｄ＋ｎは４以下である。

In the above formula (1-2), A is independently, -O- or -S-, D is a direct bond, -O -, - S -, - CO -, - SO 2 -, - SO -, - CONH -, - COO -, - (CF 2) i - (i is an integer of 1 to _{10), - (CH 2) j} - (j is an integer of 1 to 10), - CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), represents at least one structure selected from the group consisting of a cyclohexylidene group and a fluorenylidene group. , R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms, and W ² and W ³ are each independently a halogen atom. C and d are integers of 0 to 4, m and n are integers of 0 to 4, and q is an integer of 0 to 4. However, d is 0 when q = 0. Moreover, c + m and d + n are 4 or less.

  The structural unit represented by the above formula (1-1) and the structural unit represented by the above formula (1-2) are preferably 100: 0 to 50:50 at a molar ratio (1-1) :( 1-2). Is preferably contained in a ratio of 100: 0 to 75:25.

  Examples of the structural unit represented by the above formula (1-1) include the following.

本発明にかかる共重合体には、上記構造単位の他に、以下の単位を含むものであってもよい。

The copolymer according to the present invention may contain the following units in addition to the above structural units.

(Structural unit having a divalent heterocyclic group containing nitrogen)
The structural unit having a divalent heterocyclic group containing nitrogen of the present invention is represented by the following formula (2).

上記式（２）中、Ａｒ¹は、窒素を含む複素環構造を有する２価の有機基を示し、好ましくは、窒素を含む複素環構造を有する炭素数３〜３０の有機基であり、例えば、窒素を含む２価の複素環基および下記式（２−１）で表わされる基を挙げることができる。

In the above formula (2), Ar ¹ represents a divalent organic group having a heterocyclic structure containing nitrogen, preferably an organic group having 3 to 30 carbon atoms having a heterocyclic structure containing nitrogen. And a divalent heterocyclic group containing nitrogen and a group represented by the following formula (2-1).

上記式（２−１）中、Ｒ^hは、窒素を含む１価の複素環基を示し、Ａｒ²は２価の芳香族基を示し、Ｒ^sは炭素数１〜２０の２価の脂肪族炭化水素基、炭素数１〜２０の２価の脂環式炭化水素基、または２価の芳香族基を示し、Ｑ¹、Ｑ²は、各々独立に、直接結合、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ₂−又は−または−ＳＯ−からなる群より選ばれた少なくとも１種の構造を示し、ｎ１は０〜２の整数を示す。

In the above formula (2-1), R ^h represents a monovalent heterocyclic group containing nitrogen, Ar ² represents a divalent aromatic group, and R ^s represents a divalent fatty acid having 1 to 20 carbon atoms. An aromatic hydrocarbon group, a divalent alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic group, Q ¹ and Q ² are each independently a direct bond, —O—, — S -, - CO -, - SO 2 - or - or consists -SO- represents at least one structure selected from the group, n1 is an integer of 0 to 2.

^Examples of the monovalent heterocyclic group containing nitrogen represented by R ^h include nitrogen-containing 5-membered and 6-membered ring structures. Further, the number of nitrogen atoms in the heterocycle is not particularly limited as long as it is 1 or more, and the heterocycle may contain oxygen or sulfur in addition to nitrogen. Specific examples of the monovalent heterocyclic group containing nitrogen constituting R ^h include pyrrole, thiazole, isothiazole, oxazole, isoxazole, pyridine, imidazole, imidazoline, pyrazole, 1,3,5-triazine, and pyrimidine. , Nitrogen-containing heterocyclic compounds consisting of carbazole, acridine, quinoxaline, quinazoline, and derivatives thereof Is a group having a structure in which a hydrogen atom bonded to is pulled out. These nitrogen-containing heterocyclic groups may have a substituent. Examples of the substituent include alkyl groups such as a methyl group, an ethyl group, and a propyl group, and aryl groups such as a phenyl group, a toluyl group, and a naphthyl group. Group, cyano group, fluorine atom and the like.

Examples of the divalent aromatic group represented by Ar ² and R ^s include a bivalent monocyclic aromatic group such as a 1,3-phenylene group and a 1,4-phenylene group, a 1,3-naphthalenediyl group, 2 such as 1,4-naphthalenediyl group, 1,5-naphthalenediyl group, 1,6-naphthalenediyl group, 1,7-naphthalenediyl group, 2,6-naphthalenediyl group, 2,7-naphthalenediyl group, etc. And divalent aromatic heterocyclic groups such as valent condensed ring aromatic groups, pyridinediyl groups, quinoxalinediyl groups, and thiophenediyl groups. A divalent monocyclic aromatic group is preferred.

Specific examples of the divalent heterocyclic group containing nitrogen represented by Ar ¹ include pyrrole diyl group, 2H-pyrrole diyl group, imidazole diyl group, pyrazole diyl group, isothiazole diyl group, isoxazole diyl group, pyridinediyl. Group, pyrazinediyl group, pyrimidinediyl group, pyridazinediyl group, indolizinediyl group, isoindolediyl group, 3H-indolediyl group, indolediyl group, 1H-indazolediyl group, purinediyl group, 4H-quinolidinediyl group, quinolinediyl group, Isoquinolinediyl group, phthalazinediyl group, naphthyridinediyl group, quinoxalinediyl group, quinazolinediyl group, cinnolinediyl group, pteridinediyl group, carbazolediyl group, carbolinediyl group, phenanthridinediyl group, Clidinediyl group, perimidinediyl group, phenanthrolinediyl group, phenazinediyl group, phenothiazinediyl group, furazanediyl group, phenoxazinediyl group, pyrrolidinediyl group, pyrrolindiyl group, imidazolinediyl group, imidazolidinediyl group, pyrazolidinediyl group, pyrazolinediyl Group, piperidinediyl group, piperazinediyl group, indolinediyl group, isoindolinediyl group, quinuclidinediyl group, oxazolediyl group, benzoxazolediyl group, 1,3,5-triazinediyl group, brindidiyl group, tetrazolediyl group , Tetrazinediyl group, triazolediyl group, phenalsazinediyl group, benzimidazolediyl group, benzotriazolediyl group, thiazolediyl group, benzothiazolediyl And a structure derived from at least one selected from the group consisting of a group and a benzothiadiazolediyl group, or at least one structure selected from the group consisting of a structure represented by the following formula.

［上記式において、構造単位の端部における単線のうち、一方に置換基が表示されていな
いものは隣り合う構造単位との接続を意味する。］
Ｒ^sで示される炭素数１〜２０の２価の脂肪族炭化水素基としては、メチレン基、プロピレン基、ブチレン基などを挙げることができる。

[In the above formula, among the single wires at the ends of the structural units, those on which one or more substituents are not displayed mean connection with adjacent structural units. ]
Examples of the divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ^s include a methylene group, a propylene group, and a butylene group.

Examples of the divalent alicyclic hydrocarbon group having 1 to 20 carbon atoms represented by R ^s include a cyclopentylene group, a cyclohexylene group, and a cycloheptylene group.
By including a structural unit having a nitrogen-containing heterocyclic group as described above, a solid polymer electrolyte membrane having high sulfonic acid stability at high temperatures without imparting basicity and impairing proton conductivity is obtained. Can be obtained. In particular, by using in combination with the structural unit represented by the formula (1), elution to hot water in the film can be suppressed, and a film excellent in hot water resistance can be obtained.

[Structural unit having aromatic structure]
The aromatic copolymer of the present invention can contain a structural unit represented by the following formula (5) as a structural unit having an aromatic structure other than the structural unit represented by the above formula (1).

  The structural unit having an aromatic structure is represented by the following formula (5).

上記式（５）中、Ａｒ²¹、Ａｒ²²、Ａｒ²³、Ａｒ²⁴は、それぞれ独立に、ベンゼン環、縮合芳香環（ナフタレン環など）または含窒素複素環の構造を有する２価の基を示す。

In the above formula (5), Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ each independently represent a divalent group having a benzene ring, a condensed aromatic ring (such as a naphthalene ring) or a nitrogen-containing heterocyclic ring structure. .

However, in Ar ²¹ , Ar ²² , Ar ²³ , Ar ²⁴ , some or all of the hydrogen atoms may be fluorine-substituted, nitro group, nitrile groups, or some or all of the hydrogen atoms may be halogen-substituted. It may be substituted with at least one atom or group selected from the group consisting of an alkyl group, an allyl group or an aryl group.

A and D are each independently a direct bond or —CO—, —COO—, —CONH—, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — ( CH _{2) l} - _(l is an integer of 1 to _{10), - CR '2 - (} R' represents an aliphatic hydrocarbon group, aromatic hydrocarbon group or a halogenated hydrocarbon group), cyclohexylidene A group, a fluorenylidene group, -O- or S-, B is an oxygen atom or a sulfur atom,
s and t each independently represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more.

  The structural unit having an aromatic structure is preferably one represented by the following formula (5-1).

［式（５−１）中、Ａ、Ｄは独立に直接結合または、−ＣＯ−、−ＳＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基およびハロゲン化炭化水素基を示す）、シクロヘキシリデン基、フルオレニリデン基、−Ｏ−、−Ｓ−からなる群より選ばれた少なくとも１種の構造を示し、Ｂは独立に酸素原子または硫黄原子であり、Ｒ¹〜Ｒ¹⁶は、互いに同一でも異なっていてもよく、水素原子、フッ素原子、ニトロ基、ニトリル基、又は水素原子の一部またはすべてがフッ素置換されていてもよいアルキル基、アリル基若しくはアリール基からなる群より選ばれた少なくとも１種の原子または基を示す。ｓ、ｔは０〜４の整数（０，１，２）を示し、ｒは、０または１以上の整数を示す。］
本発明の重合体の分子量は、ゲルパーミエションクロマトグラフィ（ＧＰＣ）によるポリスチレン換算重量平均分子量で、１万〜１００万、好ましくは２万〜８０万、さらに好ましくは５万〜３０万である。

[In Formula (5-1), A and D are independently a direct bond, or —CO—, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ) _l - (l is an integer of 1 to _{10), - CR '2 - (} R' represents an aliphatic hydrocarbon group, aromatic hydrocarbon group or a halogenated hydrocarbon group), cyclohexylidene group, 1 represents at least one structure selected from the group consisting of a fluorenylidene group, —O—, and —S—, B is independently an oxygen atom or a sulfur atom, and R ^{1 to} R ¹⁶ are the same as or different from each other. And at least one selected from the group consisting of a hydrogen atom, a fluorine atom, a nitro group, a nitrile group, or an alkyl group, an allyl group, or an aryl group in which some or all of the hydrogen atoms may be fluorine-substituted. Indicates an atom or group. s and t represent integers (0, 1, 2) of 0 to 4, and r represents 0 or an integer of 1 or more. ]
The molecular weight of the polymer of the present invention is 10,000 to 1,000,000, preferably 20,000 to 800,000, and more preferably 50,000 to 300,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).

  The ion exchange capacity of the polymer according to the present invention is usually 0.3 to 6 meq / g, preferably 0.5 to 4 meq / g, and more preferably 0.8 to 3.5 meq / g. When the ion exchange capacity is 0.3 meq / g or more, the proton conductivity is high and the power generation performance can be improved. On the other hand, if it is 5 meq / g or less, it can have sufficiently high water resistance.

  The above ion exchange capacity can be adjusted by changing the type, usage ratio, and combination of each structural unit. Therefore, it can be adjusted by changing the charge amount ratio and type of the precursor (monomer / oligomer) that induces the structural unit during polymerization.

  In general, as the number of structural units containing sulfonic acid groups and phosphonic acid groups increases, the ion exchange capacity increases and proton conductivity increases, but the water resistance tends to decrease. On the other hand, when these structural units decrease, ion exchange increases. The capacity decreases and the water resistance increases, but the proton conductivity tends to decrease. Moreover, when the amount of phosphonic acid groups increases, radical resistance tends to increase.

  The polymer of the present invention contains the structural unit represented by the formula (1) in a proportion of 0.1 to 90 mol%, preferably 0.3 to 80 mol%, more preferably 0.5 to 60 mol%. It is desirable.

[Method for producing aromatic copolymer]
The aromatic copolymer of the present invention can be produced using, for example, the following A1 method or B1 method.

  For example, by the method described in JP-A No. 2004-137444, a sulfonic acid ester (A) that becomes a structural unit of a polymer segment having a sulfonic acid group, or a structural unit of a polymer segment that has substantially no sulfonic acid group It can be synthesized by copolymerizing the compound (B) and, if necessary, the compound (C) to be a structural unit having a nitrogen-containing heterocyclic group and converting the sulfonic acid ester group to a sulfonic acid group.

Sulfonic acid or its ester compound (A) (hereinafter also referred to as “compound A”))
Compound A is a monomer having a sulfonic acid or its ester group.
The polymer segment having the structural unit represented by the structural unit (3) may be introduced by using, for example, a compound represented by the following formula (3-4) as a polymerization raw material for the aromatic copolymer. it can.

式（３−４）で、Ａｒ¹¹、Ａｒ¹²、Ａｒ¹³、Ｙ、Ｚ、Ｒ²²、Ｒ²³、Ｒ²⁴、ｘ¹、ｘ²、ａ、ｂは、前記（３）と同義である。

In the formula (3-4), Ar ¹¹ , Ar ¹² , Ar ¹³ , Y, Z, R ²² , R ²³ , R ²⁴ , x ¹ , x ² , a, b are as defined in the above (3).

  X represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, benzenesulfonyl group, toluenesulfonyl group, and nitro group.

Y represents —CO—, —CONH—, —COO—, —SO ₂ —, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C (CF ₃ ) _2. -Represents at least one structure selected from the group consisting of direct bonds. Z is —O—, —S—, direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) Shows at least one structure selected from the group consisting of _2- .

When a is 2 or more, () a, Y, Z, b, x ¹ , Ar ¹² , Ar ¹³ , R ²² , and R ^{23 in a} may be the same or different.
The monomer represented by the above formula (3-4) preferably has a structure represented by the following formula (3-5) or a structure represented by the following formula (3-6).

式（３−５）中、Ｘ¹は塩素原子、臭素原子および−ＯＳＯ₂Ｒｂ（ここで、Ｒｂはアルキル基、フッ素置換アルキル基またはアリール基を示す）から選ばれる原子または基を示す。

In formula (3-5), X ¹ represents an atom or group selected from a chlorine atom, a bromine atom and —OSO ₂ Rb (where Rb represents an alkyl group, a fluorine-substituted alkyl group or an aryl group).

Y, Z, and k are the same as in equation (3-4).
c is an integer of 0 to 10, preferably 0 to 2, d is an integer of 0 to 10, preferably 0 to 2, and k is an integer of 1 to 4. When c and d are 2 or more, Z, R and k in () c and () d may be the same or different.

Ar is an aromatic group having a substituent represented by —SO ₃ R or —O (CH ₂ ) _h SO ₃ R or —O (CF ₂ ) _h SO ₃ R (h represents an integer of 1 to 12). Indicates. R is a branched or straight chain alkyl group, a cycloalkyl group, or a heterocyclic group containing oxygen as a hetero atom, and preferably has 4 to 20 carbon atoms. A part of R may be substituted with a hydrogen atom.

  Specific examples of the compound represented by the formula (3-5) include a compound represented by the following formula, Japanese Patent Application Laid-Open Nos. 2004-137444, 2004-345997, and 2004-346163. Can be mentioned.

式（３−５）で表される化合物において、スルホン酸エステル構造は、通常、芳香族環のメタ位に結合している。

In the compound represented by the formula (3-5), the sulfonate structure is usually bonded to the meta position of the aromatic ring.

上記式（３−６）中、Ｘ²はハロゲン原子、ニトロ基、−ＳＯ₂ＣＨ₃および−ＳＯ₂ＣＦ₃から選ばれる原子または基、Ｒ^aは、−ＯＲ^bで表わされる基（Ｒ^bは、炭素数１〜２０の１価の炭化水素基または炭素数１〜２０の１価のハロゲン化炭化水素基を示す。）、炭素数１〜２０の炭化水素基および炭素数１〜２０の炭化水素基から選ばれる少なくとも一種の基で置換されたアミノ基を示し、Ｒ¹、ａ、ｋは、上記式（３−２）中のＲ¹、ａ、ｋと同義である。

In the above formula (3-6), X ² is an atom or group selected from a halogen atom, a nitro group, —SO ₂ CH ₃ and —SO ₂ CF ₃ , and R ^a is a group represented by —OR ^b (R ^b Represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms.), A hydrocarbon group having 1 to 20 carbon atoms and a 1 to 20 carbon atom substituted with at least one group selected from hydrocarbon groups which showed amino group, R ^1, a, k is R ^1, a, synonymous with k in the above formula (3-2).

R ^a may be the same or different and represents a hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrocarbon group having 4 to 20 carbon atoms. Specifically, tert-butyl group, iso-butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantylmethyl group, adamantylmethyl group 2-ethylhexyl group, bicyclo [2.2.1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl group, 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolane Examples include a straight chain hydrocarbon group such as a methyl group, a branched hydrocarbon group, an alicyclic hydrocarbon group, and a hydrocarbon group having a 5-membered heterocycle. Of these, n-butyl, neopentyl, tetrahydrofurfuryl, cyclopentylmethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, adamantylmethyl and bicyclo [2,2,1] heptylmethyl are preferred, and neopentyl. The group is most preferred.

Compound (B) which is a structural unit of a polymer segment substantially having no sulfonic acid group (hereinafter also referred to as “Compound B”)
The polymer segment having substantially no sulfonic acid group can be introduced, for example, by using a compound represented by the following formula (1 ′) as a polymerization raw material for the aromatic copolymer.

（上記式（１’）中、Ｒ¹、Ｌ、ａ、ｐは式（１）と同じであり、Ｚ¹はハロゲン原子、ニトロ基、−ＳＯ₂ＣＨ₃および−ＳＯ₂ＣＦ₃から選ばれる原子または基を示す。

(In the above formula (1 ′), R ¹ , L, a and p are the same as in formula (1), and Z ¹ is selected from a halogen atom, a nitro group, —SO ₂ CH ₃ and —SO ₂ CF _3. Indicates an atom or group.

The number average molecular weight in terms of polystyrene of the precursor represented by the formula (1 ′) is desirably in the range of 1,000 to 50,000.
Furthermore, the compound represented by the above formula (1 ′) can be synthesized, for example, by the following reaction.

  A dihalide represented by the following formula (1′-1) and a di (thio) phenol represented by (1′-2): N-methyl-2-pyrrolidone, N, N-dimethylacetamide, After dissolving in a polar solvent having a high dielectric constant such as sulfolane, diphenyl sulfone, dimethyl sulfoxide, etc., an alkali metal such as lithium, sodium or potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate or the like is added. The alkali metal is reacted in excess with respect to the hydroxyl group of phenol, and is usually used in an amount of 1.1 to 2 times equivalent, preferably 1.2 to 1.5 times equivalent. At this time, it is preferable to promote the progress of the reaction by coexisting a solvent azeotropic with water such as benzene, toluene, xylene, chlorobenzene, and anisole.

式（１’−１）で表わされるジハロゲン化物としては、例えば、４，４’−ジクロロベンゾスルホン（４，４’−ＤＣＢＰ）、４，４’−ジフルオロスルホン（４，４’−ＤＦＢＰ）、４−クロロ−４’−フルオロスルホン、２−クロロ−４’−フルオロベンゾスルホン、などが挙げられる。これらのジハロゲン化物は、１種単独で用いてもよいし、２種以上を併用しても良い。
（上記式（1'-1）中、Ｒ¹、aは式（１）と同義であり、Ｚ¹はハロゲン原子、ニトロ基、−ＳＯ₂ＣＨ₃および−ＳＯ₂ＣＦ₃から選ばれる原子または基を示す。）
ＨＡ−Ｌ−ＡＨ （１’−２）
（上記式（1'-2）中、Ａは式（１−１）と同義である。）

Examples of the dihalide represented by the formula (1′-1) include 4,4′-dichlorobenzosulfone (4,4′-DCBP), 4,4′-difluorosulfone (4,4′-DFBP), 4-chloro-4'-fluorosulfone, 2-chloro-4'-fluorobenzosulfone, and the like can be mentioned. These dihalides may be used individually by 1 type, and may use 2 or more types together.
(In the above formula (1′-1), R ¹ and a have the same meanings as in formula (1), and Z ¹ is an atom selected from a halogen atom, a nitro group, —SO ₂ CH ₃ and —SO ₂ CF ₃ or Group.)
HA-L-AH (1'-2)
(In the above formula (1′-2), A has the same meaning as in formula (1-1).)

  The structural unit having a nitrogen-containing heterocyclic group represented by the above formula (2) is, for example, a compound (C) represented by the following formula (2-2) (hereinafter referred to as “compound”) as a raw material for an aromatic copolymer. C ”) can be introduced into the aromatic polymer.

上記式（２−２）中、Ａｒ¹は上記式（２）中のＡｒ¹と同義であり、Ｚ³はハロゲン原子、ニトロ基、−ＳＯ₃ＣＨ₃基およびＳＯ₃ＣＦ₃から選ばれる原子または基を示す。

In the formula (2-2), Ar ¹ has the same meaning as Ar ¹ in the formula (2), Z ³ is atom selected from a halogen atom, a nitro group, -SO ₃ CH ₃ groups, and SO ₃ CF ₃ Or a group.

When Ar ¹ is a divalent heterocyclic group containing nitrogen, examples of the compound represented by the above formula (2-2) include 1-methyl-2,5-dichloropyrrole, 1- Hexyl-2,5-dibromopyrrole, 1-octyl-2,5-dichloropyrrole, 2,5-dichloropyridine, 3,5-dichloropyridine, 2,5-dibromopyridine, 3-methyl-2,5-dichloro Pyridine, 3-hexyl-2,5-dichloropyridine, 5,5′-dichloro-2,2′-bipyridine, 3,3′-dimethyl-5,5′-dichloro-2,2′-bipyridine, 3, 3'-dioctyl-5,5'-dibromo-2,2'-bipyridine, 2,5-dichloropyrimidine, 2,5-dibromopyrimidine, 5,8-dichloroquinoline, 5,8-dibromoquinoline, 2,6 -Dichloroquinoline, 1,4-dichloroisoquinoline, 5,8-dibromoisoquinoline, 4,7-dibromo-2,1,3-benzothiadiazole, 4,7-dichlorobenzimidazole, 5,8-dichloroquinoxaline, 5,8-dichloro- Examples include 2,3-diphenylquinoxaline and 2,6-dibromoquinoxaline.

When Ar ² is a group represented by the above formula (2-1), specifically, as the compound represented by the above formula (2-2), a compound represented by the following formula (2-3) Can be mentioned.

上記式（２−３）中、Ｒ^h、Ｒ^s、Ａｒ²、Ｑ¹、Ｑ²、ｎ１は、式（２−１）中のＲ^h、Ｒ^s、Ａｒ²、Ｑ¹、Ｑ²、ｎと同義であり、Ｚ³はハロゲン原子、ニトロ基、−ＳＯ₃ＣＨ₃基およびＳＯ₃ＣＦ₃から選ばれる原子または基を示す。

In the above formula (2-3), R ^h , R ^s , Ar ² , Q ¹ , Q ² , and n1 are R ^h , R ^s , Ar ² , Q ¹ , Q ² , It is synonymous with n, and Z ³ represents an atom or group selected from a halogen atom, a nitro group, a —SO ₃ CH ₃ group and a SO ₃ CF ₃ .

  Specific examples of the compound represented by the above formula (2-3) include the following compounds.

さらに、塩素原子が臭素原子に置き換わった化合物、塩素原子や臭素原子の結合位置の異なる異性体を挙げることができる。また−ＣＯ−結合が、−ＳＯ₂−結合に置き換わった化合物を挙げることができる。これらの化合物は、単独で用いてもよく、２種類以上を併用してもよい。

Furthermore, compounds in which a chlorine atom is replaced with a bromine atom, and isomers having different bonding positions of chlorine and bromine atoms can be exemplified. In addition, a compound in which a —CO— bond is replaced with a —SO ₂ — bond can be exemplified. These compounds may be used alone or in combination of two or more.

  The structural unit represented by the above formula (5) is derived from a structural unit having an aromatic structure and a monomer (also referred to as compound D) comprising the following formula (5-3).

（式（５−３）中、Ａｒ²¹、Ａｒ²²、Ａｒ²³、Ａｒ²⁴は、ベンゼン環、縮合芳香環（ナフタレン環など）、含窒素複素環からなる群より選ばれた少なくとも１種の構造を示す。ただし、Ａｒ²¹、Ａｒ²²、Ａｒ²³、Ａｒ²⁴は、それぞれの水素原子が、フッ素原子、アルキル基、一部またはすべてがフッ素置換されたハロゲン化アルキル基、アリル基、アリール基、ニトロ基、ニトリル基で置換されていてもよい。

(In the formula (5-3), Ar ²¹ , Ar ²² , Ar ²³ and Ar ²⁴ are at least one structure selected from the group consisting of a benzene ring, a condensed aromatic ring (such as a naphthalene ring), and a nitrogen-containing heterocyclic ring. However, Ar ²¹ , Ar ²² , Ar ²³ , and Ar ²⁴ are each a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which part or all of them are fluorine-substituted, an allyl group, an aryl group, It may be substituted with a nitro group or a nitrile group.

X ² represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, benzenesulfonyl group, and toluenesulfonyl group.

A and D are independently a direct bond, or —CO—, —COO—, —CONH—, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ). _l— (l is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene And at least one structure selected from the group consisting of a group, —O—, and —S—, B is independently an oxygen atom or a sulfur atom, s and t are integers of 0 to 4, and r Represents 0 or an integer of 1 or more. )

  The structural unit having an aromatic structure can be obtained by using, for example, an oligomer represented by the following general formula (5-4) as a polymerization raw material for an aromatic copolymer.

［上記式（５−４）中、Ｘ²は、塩素、臭素、ヨウ素、メタンスルホニル基、トリフルオロメタンスルホニル基、ベンゼンスルホニル基からなる群より選ばれた少なくとも１種の構造を示す。Ａ、Ｄは独立に直接結合または、−ＣＯ−、−ＳＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基およびハロゲン化炭化水素基を示す）、シクロヘキシリデン基、フルオレニリデン基、−Ｏ−、−Ｓ−からなる群より選ばれた少なくとも１種の構造を示し、
Ｂは独立に酸素原子または硫黄原子であり、
Ｒ¹〜Ｒ¹⁶は、互いに同一でも異なっていてもよく、水素原子、フッ素原子、アルキル基、一部またはすべてがハロゲン化されたハロゲン化アルキル基、アリル基、アリール基、ニトロ基、ニトリル基からなる群より選ばれた少なくとも１種の原子または基を示す。ｓ、ｔは０〜４の整数を示し、ｒは０または１以上の整数を示す。］
上記式（５−４）で表されるオリゴマーの具体的な例としては、下記が挙げられる。

[In the above formula (5-4), X ² represents at least one structure selected from the group consisting of chlorine, bromine, iodine, methanesulfonyl group, trifluoromethanesulfonyl group, and benzenesulfonyl group. A and D are independently a direct bond, or —CO—, —SO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ) ₁ — (l is 1 to 10 -CR ' _2- (R' represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, -O-, -S At least one structure selected from the group consisting of:
B is independently an oxygen atom or a sulfur atom,
R ^{1 to} R ¹⁶ may be the same as or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which a part or all of them are halogenated, an allyl group, an aryl group, a nitro group, a nitrile group. At least one atom or group selected from the group consisting of s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. ]
Specific examples of the oligomer represented by the above formula (5-4) include the following.

また、上記化合物において塩素原子が臭素原子に置き換わった化合物なども挙げられる。また、塩素原子や臭素原子の結合位置の異なる異性体も挙げることができる。

Moreover, the compound etc. which the chlorine atom replaced the bromine atom in the said compound are mentioned. In addition, isomers having different bonding positions of chlorine atoms and bromine atoms can also be mentioned.

  The oligomers represented by the above formulas (5-3) and (5-4) can be produced, for example, by copolymerizing the following monomers. When r = 0 in the formulas (5-3) and (5-4), for example, 4,4′-dichlorobenzophenone, 4,4′-dichlorobenzanilide, 2,2-bis (4-chlorophenyl) difluoromethane, 2,2-bis (4-chlorophenyl) -1,1,1,3,3,3-hexafluoropropane, 4-chlorobenzoic acid-4-chlorophenyl ester, bis (4-chlorophenyl) sulfoxide, bis (4- Chlorophenyl) sulfone and 2,6-dichlorobenzonitrile.

  In these compounds, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom is exemplified. In the case of r = 1, for example, compounds described in JP-A-2003-113136 can be exemplified.

  In the case of r ≧ 2, for example, Japanese Patent Application Laid-Open No. 2004-137444, Japanese Patent Application Laid-Open No. 2004-244517, Japanese Patent Application No. 2003-143914 (Japanese Patent Application Laid-Open No. 2004-346164), Japanese Patent Application No. 2003-348523 (Japanese Patent Application Laid-Open No. 2005-348523). No. 112985), Japanese Patent Application No. 2003-348524, Japanese Patent Application No. 2004-211739 (Japanese Patent Application Laid-Open No. 2006-28414), Japanese Patent Application No. 2004- 211740 (Japanese Patent Application Laid-Open No. 2006-28415), and the like. Can do.

In order to obtain an aromatic copolymer for the purpose of the polymerization method , first, the above-mentioned various compounds are copolymerized to obtain a precursor. This copolymerization is carried out in the presence of a catalyst, and the catalyst used in this case is a catalyst system containing a transition metal compound. This catalyst system is (1) a transition metal salt and a ligand. A compound (hereinafter referred to as “ligand component”) or a transition metal complex coordinated with a ligand (including a copper salt) and (2) a reducing agent as essential components, and further increase the polymerization rate. Therefore, salts other than transition metal salts may be added.

  Here, transition metal salts include nickel compounds such as nickel chloride, nickel bromide, nickel iodide, nickel acetylacetonate, palladium compounds such as palladium chloride, palladium bromide, palladium iodide, iron chloride, iron bromide And iron compounds such as iron iodide and cobalt compounds such as cobalt chloride, cobalt bromide and cobalt iodide. Of these, nickel chloride, nickel bromide and the like are particularly preferable. The ligand includes triphenylphosphine, tri (2-methyl) phenylphosphine, tri (3-methyl) phenylphosphine, tri (4-methyl) phenylphosphine, 2,2′-bipyridine, 1,5- Examples thereof include cyclooctadiene, 1,3-bis (diphenylphosphino) propane, and triphenylphosphine, tri (2-methyl) phenylphosphine, and 2,2′-bipyridine are preferable. The said ligand can be used individually by 1 type or in combination of 2 or more types.

  Furthermore, as the transition metal (salt) in which the ligand is coordinated in advance, for example, nickel chloride bis (triphenylphosphine), nickel chloride bis (tri (2-methyl) phenylphosphine), nickel bromide bis (triphenyl) Phosphine), nickel iodide bis (triphenylphosphine), nickel nitrate bis (triphenylphosphine), nickel chloride (2,2′bipyridine), nickel bromide (2,2′bipyridine), nickel iodide (2,2) 'Bipyridine), nickel nitrate (2,2'bipyridine), bis (1,5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel, tetrakis (triphenylphosphine) palladium Nickel chloride Scan (triphenylphosphine), nickel chloride bis (tri (2 Mechiru) phenyl phosphine), nickel chloride (2,2'-bipyridine) are preferred.

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

  Examples of salts other than transition metal salts that can be used in the catalyst system of the present invention include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, potassium fluoride, and potassium chloride. Potassium compounds such as potassium bromide, potassium iodide, and potassium sulfate, and ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetraethylammonium sulfate. Sodium, sodium iodide, potassium bromide, tetraethylammonium bromide and tetraethylammonium iodide are preferred.

  The proportion of each component in the catalyst system is such that the transition metal salt or the transition metal (salt) coordinated with the ligand can be a structural unit represented by the above general formula (1) and the sulfonic acid group The amount is generally 0.0001 to 10 mol, preferably 0.01 to 0.5 mol, relative to a total of 1 mol with the compound B that can be a structural unit having a. If it is in this range, the polymerization reaction is sufficiently promoted, the catalytic activity is high, and the molecular weight can be increased. When the amount is less than the above range, the polymerization reaction does not proceed sufficiently. On the other hand, when the amount is too large, the molecular weight is lowered. In the catalyst system, when a transition metal salt and a ligand are used, the proportion of the ligand used is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. If the amount is less than 0.1 mol, the catalytic activity becomes insufficient. On the other hand, if the amount exceeds 100 mol, the molecular weight decreases.

  In addition, the ratio of the reducing agent used in the catalyst system is usually based on 1 mol in total of the compound A that can be a structural unit represented by the general formula (1) and the compound B that can be a structural unit having a sulfonic acid group. 0.1 to 100 mol, preferably 1 to 10 mol. If it exists in this range, superposition | polymerization will fully advance and a polymer can be obtained with a high yield. Further, when the lower limit of the above range is satisfied, the polymerization does not proceed sufficiently. On the other hand, when the upper limit is exceeded, there is a problem that it is difficult to purify the resulting polymer.

  Further, when a salt other than a transition metal salt is used in the catalyst system, the proportions used are the compound A that can be a structural unit represented by the general formula (1) and the compound B that can be a structural unit having a sulfonic acid group. Is generally 0.001 to 100 mol, preferably 0.01 to 1 mol, per 1 mol in total. When the amount is less than 0.001 mol, the effect of increasing the polymerization rate is insufficient. On the other hand, when the amount exceeds 100 mol, there is a problem that it is difficult to purify the resulting polymer.

In addition, when it contains other compounds C and D, it becomes the catalyst amount with respect to these total amounts.
Examples of the polymerization solvent that can be used in the present invention include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone, γ-butyrolactone, γ- Examples include butyrolactam, and tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, and 1-methyl-2-pyrrolidone are preferable. These polymerization solvents are preferably used after sufficiently dried. The concentration of the compound A that can be a structural unit represented by the general formula (1) and the compound B that can be a structural unit having a sulfonic acid group in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40%. % By weight.

  When a structural unit having a nitrogen-containing heterocyclic group or other structural unit is introduced, a monomer such as compound C or D is added when reacting compound A and B, or compound A or B Any one of the above may be reacted in advance with compound C or D, and then reacted with one of compounds A or B that has not been reacted. The reaction conditions may be based on the above conditions.

The reaction of compounds A, B, C, etc. corresponds to the composition of each structural unit with the charged amount as it is.
Moreover, the polymerization temperature at the time of superposing | polymerizing the polymer of this invention is 0-200 degreeC normally, Preferably it is 50-80 degreeC. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

In the above production method, the ester group of the sulfonic acid ester group contained in the obtained copolymer is converted to a sulfonic acid group (—SO ₃ H) as necessary.
In particular,
(1) A method in which the aromatic copolymer is added to an excess amount of water or alcohol containing a small amount of hydrochloric acid and stirred for 5 minutes or more. (2) The aromatic copolymer is 80 in trifluoroacetic acid. Method of reacting at a temperature of about 120 ° C. for about 5 to 10 hours (3) 1 to 9 moles of lithium bromide per mole of sulfonic acid ester group (—SO ₃ R) in the aromatic copolymer Examples include a method in which hydrochloric acid is added after the aromatic copolymer is reacted at a temperature of about 80 to 150 ° C. for about 3 to 10 hours in a solution such as N-methylpyrrolidone. .

  Note that in the case of a sulfonic acid metal salt, hydrogen replacement may be performed by a method such as ion exchange.

[Polymer electrolyte membrane]
The aromatic copolymer of the present invention includes a proton conducting membrane, an electrolyte for a primary battery, an electrolyte for a secondary battery, a solid polymer electrolyte for a fuel cell, a display element, various sensors, a signal transmission medium, a solid capacitor, and an ion exchange membrane. For example, the membrane state, the solution state, and the powder state may be used. Of these, the membrane state and the solution state are preferable (hereinafter, the membrane state is referred to as a polymer electrolyte membrane).

  The solid polymer electrolyte membrane according to the present invention contains the aromatic copolymer. The dry film thickness of the solid polymer electrolyte membrane according to the present invention is usually 10 to 100 μm, preferably 20 to 80 μm.

  The solid polymer electrolyte membrane according to the present invention can also contain a metal compound or a metal ion. Other metal compounds or metal ions include aluminum (Al), manganese (Mn), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), Ruthenium (Ru), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), cerium (Ce), vanadium (V), neodymium (Nd), praseodymium (Pr), Metal compounds containing metal atoms such as samarium (Sm), cobalt (Co), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), and erbium (Er), or these metal ions Can be mentioned.

The solid polymer electrolyte membrane according to the present invention can also contain a fluorine-containing polymer. As the fluorine-containing polymer, a solvent-soluble compound is preferably used because the fluorine-containing polymer can be uniformly dispersed in the pores of the electrolyte membrane or the porous substrate. The fluorine-containing polymer is not particularly limited, and examples thereof include vinylidene fluoride homo (co) polymers, fluoroolefin / hydrocarbon olefin copolymers, fluoroacrylate copolymers, fluoroepoxy compounds and the like. Can be used.
The electrolyte membrane thus obtained is used as a proton conducting membrane.

Production method of polymer electrolyte membrane The polymer electrolyte membrane of the present invention is produced by, for example, a casting method in which the aromatic copolymer is mixed in an organic solvent and cast onto a substrate to form a film. can do. Here, the substrate is not particularly limited as long as it is a substrate used in a normal solution casting method. For example, a substrate made of plastic, metal, or the like is used, and preferably a heat treatment such as a polyethylene terephthalate (PET) film. A substrate made of a plastic resin is used.

  The solvent for mixing the aromatic copolymer may be any solvent that dissolves the copolymer or a solvent that swells, such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, γ-butyrolactone. , N, N-dimethylacetamide, dimethylsulfoxide, dimethylurea, dimethylimidazolidinone, acetonitrile, and other aprotic polar solvents, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene and other chlorinated solvents, methanol , Ethanol, propanol, iso-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol and other alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl Alkylene glycol monoalkyl ethers such as ether, acetone, methyl ethyl ketone, cyclohexanone, ketones such as γ- butyrolactone, tetrahydrofuran, solvents such as ethers 1,3-dioxane and the like. These solvents can be used alone or in combination of two or more. In particular, N-methyl-2-pyrrolidone (hereinafter also referred to as “NMP”) is preferable in terms of solubility and solution viscosity.

  When a mixture of an aprotic polar solvent and another solvent is used as the solvent, the composition of the mixture is 95 to 25% by weight of the aprotic polar solvent, preferably 90 to 25% by weight, The solvent is 5 to 75% by weight, preferably 10 to 75% by weight (however, the total is 100% by weight). When the amount of the other solvent is within the above range, the effect of lowering the solution viscosity is excellent. In this case, the combination of the aprotic polar solvent and the other solvent is preferably NMP as the aprotic polar solvent and methanol having an effect of lowering the solution viscosity in a wide composition range as the other solvent.

  The polymer concentration of the solution in which the copolymer and the additive are dissolved depends on the molecular weight of the sulfonic acid-containing aromatic copolymer, but is usually 5 to 40% by weight, preferably 7 to 25% by weight. is there. If it is less than 5% by weight, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.

  The solution viscosity is usually 2,000 to 100,000 mPa · s, preferably 3,000 to 50, although depending on the molecular weight of the aromatic copolymer, the polymer concentration, and the concentration of the additive. 000 mPa · s. If it is less than 2,000 mPa · s, the retention of the solution during film formation is poor and it may flow from the substrate. On the other hand, if it exceeds 100,000 mPa · s, the viscosity is too high to be extruded from the die, and it may be difficult to form a film by the casting method.

  After film formation as described above, when the obtained undried film is immersed in water, the organic solvent in the undried film can be replaced with water, and the amount of residual solvent in the resulting polymer electrolyte membrane is reduced. can do.

  In addition, after film formation, before immersing an undried film in water, you may predry an undried film. The preliminary drying is performed by holding the undried film at a temperature of usually 50 to 150 ° C. for 0.1 to 10 hours.

  When the undried film is immersed in water and dried as described above, a film with a reduced amount of residual solvent is obtained. The residual solvent amount of the film thus obtained is usually 5% by weight or less. Further, depending on the dipping conditions, the amount of residual solvent in the obtained film can be set to 1% by weight or less. As such conditions, for example, the amount of water used relative to 1 part by weight of the undried film is 50 parts by weight or more, the temperature of the water when immersed is 10 to 60 ° C., and the immersion time is 10 minutes to 10 hours. is there.

  After immersing the undried film in water as described above, the film is dried at 30-100 ° C, preferably 50-80 ° C, for 10-180 minutes, preferably 15-60 minutes, and then at 50-150 ° C. The film can be obtained by vacuum drying under reduced pressure of 500 mmHg to 0.1 mmHg for 0.5 to 24 hours.

The polymer electrolyte membrane obtained by the method of the present invention has a dry film thickness of usually 10 to 100 μm, preferably 20 to 80 μm.
In addition, after the aromatic copolymer having the sulfonic acid ester group or the alkali metal salt of sulfonic acid is formed into a film by the method described above, it is subjected to appropriate post-treatment such as hydrolysis and acid treatment. The polymer electrolyte membrane according to the present invention can also be produced. Specifically, an aromatic copolymer having a sulfonic acid ester group or an alkali metal salt of sulfonic acid is formed into a film by the above-described method, and then the membrane is hydrolyzed or acid-treated for hydrolysis. A polymer electrolyte membrane made of a group copolymer can be produced.

  In addition, when producing the polymer electrolyte membrane, in addition to the above aromatic copolymer, inorganic acids such as sulfuric acid and phosphoric acid, phosphate glass, tungstic acid, phosphate hydrate, β-alumina proton substitution product Inorganic proton conductor particles such as proton-introduced oxides, organic acids containing carboxylic acids, organic acids containing sulfonic acids, organic acids containing phosphonic acids, and appropriate amounts of water may be used in combination.

Further, when the polymer electrolyte membrane is produced, a reinforced solid polymer electrolyte membrane can also be produced by using a porous substrate or a sheet-like fibrous material.
As a method for producing a reinforced solid polymer electrolyte membrane, for example, a liquid composition is impregnated into a porous base material or a sheet-like fibrous material, and the aromatic copolymer is used as a porous base material or A method of filling the pores inside the sheet-like fibrous material, the liquid composition is applied to a porous substrate or a sheet-like fibrous material, and the aromatic copolymer is added to the porous substrate or A method of filling the pores inside the sheet-like fibrous substance, and after forming a film from the liquid composition, the film is laminated on a porous substrate or a sheet-like fibrous substance and hot pressed, Examples thereof include a method of filling the aromatic copolymer into the pores of a porous substrate or a sheet-like fibrous material.

  Further, when forming a solid polymer electrolyte membrane having a multilayer structure, a die coat, spray coat, knife coat, roll coat, spin coat, gravure is further applied to the surface of the solid polymer electrolyte membrane obtained by the above-described methods. The composition containing the aromatic copolymer is applied by a known method such as coating, and dried as necessary, or a film formed from the composition containing the aromatic copolymer is described above. For example, the film obtained by the above method may be hot-pressed on the film. The thickness of the polymer layer may be adjusted by adjusting the coating amount. For example, one polymer layer may be thick and the other thin.

  The porous substrate is not particularly limited as long as it has a large number of pores or voids penetrating in the thickness direction. For example, organic porous substrates made of various resins, glass, alumina Inorganic porous base materials composed of metal oxides and metals themselves.

The porous substrate may have a large number of through holes penetrating in a direction substantially parallel to the thickness direction.
As such a porous substrate, JP 2008-119662 A, JP 2007-154153 A, JP 8-20660 A, JP 8-20660 A, JP 2006-120368 A, What was disclosed by Unexamined-Japanese-Patent No. 2004-171994 and 2009-64777 can be used.

  As the porous substrate used in the present invention, an organic porous substrate is preferable, and specifically, polyolefins such as polytetrafluoroethylene, high molecular weight polyethylene, cross-linked polyethylene, polyethylene and polypropylene, polyimide, polyacrylo What consists of 1 or more types chosen from the group which consists of tolyl, polyamideimide, polyetherimide, polyethersulfone, and glass is preferable. The polyolefin is preferably high molecular weight polyethylene, cross-linked polyethylene, polyethylene or the like.

[Membrane-electrode assembly]
The membrane-electrode assembly according to the present invention is a membrane-electrode assembly comprising the solid polymer electrolyte membrane, a catalyst layer, and a gas diffusion layer. Typically, a catalyst layer for the cathode electrode is provided on one side of the solid polymer electrolyte membrane, and a catalyst layer for the anode electrode is provided on the other side, and each of the catalyst layers on the cathode side and the anode side is further provided. Gas diffusion layers are provided on the cathode side and the anode side, respectively, in contact with the side opposite to the solid polymer electrolyte membrane.

Known gas diffusion layers and catalyst layers can be used without particular limitation.
Specifically, the gas diffusion layer is composed of a porous substrate or a laminated structure of a porous substrate and a microporous layer. When the gas diffusion layer is composed of a laminated structure of a porous substrate and a microporous layer, the microporous layer is provided in contact with the catalyst layer. The gas diffusion layers on the cathode side and the anode side preferably contain a fluoropolymer in order to impart water repellency.

  The catalyst layer is composed of a catalyst and an ion exchange resin electrolyte. As the catalyst, a noble metal catalyst such as platinum, palladium, gold, ruthenium or iridium is preferably used. The noble metal catalyst may contain two or more elements such as an alloy or a mixture. As such noble metal catalyst, one supported on high specific surface area carbon fine particles can be used.

  The ion exchange resin electrolyte functions as a binder component for binding the carbon carrying the catalyst, and at the anode electrode, efficiently supplies ions generated by the reaction on the catalyst to the solid polymer electrolyte membrane. Then, ions supplied from the solid polymer electrolyte membrane are efficiently supplied to the catalyst.

  The ion exchange resin for the catalyst layer used in the present invention is preferably a polymer having a proton exchange group in order to improve proton conductivity in the catalyst layer. Proton exchange groups contained in such polymers include sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups, but are not particularly limited. Further, such a polymer having a proton exchange group is also selected without any particular limitation, but a polymer having a proton exchange group composed of a fluoroalkyl ether side chain and a fluoroalkyl main chain, a sulfonic acid group An aromatic hydrocarbon polymer having the same is preferably used. In addition, an aromatic hydrocarbon polymer having a sulfonic acid group constituting the solid polymer electrolyte membrane (copolymer of the present invention) may be used as an ion exchange resin, and further has a proton exchange group. It may be a polymer containing a fluorine atom, another polymer obtained from ethylene or styrene, or a copolymer or blend thereof. As such an ion exchange resin electrolyte, a known one can be used without any particular limitation, and for example, Nafion (DuPont, registered trademark), an aromatic hydrocarbon polymer having a sulfonic acid group, or the like can be used without any particular limitation. .

  If necessary, a resin having no carbon fiber or ion exchange group may be used for the catalyst layer used in the present invention. These resins are preferably resins with high water repellency. For example, fluorine-containing copolymers, silane coupling agents, silicone resins, waxes, polyphosphazenes and the like can be mentioned, and fluorine-containing copolymers are preferred.

[Fuel cell]
The polymer electrolyte fuel cell according to the present invention includes the membrane-electrode assembly. Specifically, at least one electricity generation unit including at least one membrane-electrode assembly and separators located on both sides thereof; a fuel supply unit that supplies fuel to the electricity generation unit; and an oxidant as the electricity A fuel cell including an oxidant supply unit for supplying to a generation unit, wherein the membrane-electrode assembly is as described above.

  As the separator used in the battery of the present invention, those used in ordinary fuel cells can be used. Specifically, carbon type or metal type can be used.

  Moreover, as a member which comprises a fuel cell, it is possible to use a well-known thing without a restriction | limiting in particular. The battery of the present invention can be used as a single cell, or can be used as a stack in which a plurality of single cells are connected in series. As a stacking method, a known method can be used. Specifically, planar stacking in which single cells are arranged in a plane and bipolar stacking in which single cells are stacked via separators each having a fuel or oxidant flow path formed on the back surface of the separator can be used. .

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In Examples, “%” means “% by weight” unless otherwise specified.

[Preparation of electrolyte membrane for evaluation]
After the copolymer obtained in each Example / Comparative Example was dissolved in an N-methylpyrrolidone / methanol solution, it was cast on a PET substrate using an applicator, and 60 ° C. × 30 minutes, 80 ° C. using an oven. × 40 minutes, 120 ° C. × 60 minutes. The dried membrane was immersed in deionized water. After immersion, a film for evaluation was obtained by drying at 50 ° C. for 45 minutes.

[Molecular weight]
The copolymer obtained in each Example / Comparative Example was dissolved in an N-methylpyrrolidone buffer solution (hereinafter referred to as NMP buffer solution), and subjected to gel permeation chromatography (GPC) to obtain a polystyrene-equivalent number average molecular weight ( Mn) and weight average molecular weight (Mw) were determined. The NMP buffer solution was prepared at a ratio of NMP (3 L) / phosphoric acid (3.3 mL) / lithium bromide (7.83 g).

[Equivalent of sulfonic acid group]
The resulting sulfonated polymer was washed with distilled water until the washing water became neutral to remove free remaining acid, and then dried. Thereafter, a predetermined amount is weighed, dissolved in a mixed solvent of THF / water, titrated with a standard solution of NaOH using phenolphthalein as an indicator, and the equivalent of sulfonic acid groups (ion exchange capacity) from the neutral point. (Meq / g) was determined.

[Hot water test: How to determine swelling shrinkage]
The film was cut into 2.0 cm × 3.0 cm and weighed to obtain a test piece for testing. After conditioning under conditions of 24 ° C. and 50% relative humidity (RH), this film is put into a polycarbonate 250 ml bottle, about 100 ml of distilled water is added thereto, and a pressure cooker tester (manufactured by HIRAYAMA MFS CORP) is used. And PC-242HS) for 24 hours at 120 ° C. After completion of the test, each film was taken out from the hot water, the surface water was gently wiped off with Kimwipe, the dimensions were measured, and the swelling rate was determined. The film was conditioned at 24 ° C. and RH 50%, water was distilled off, and the dimensions of the film after the hot water test were measured to determine the shrinkage. The amount of swelling and shrinkage was determined according to the following formula.
Swelling ratio = (size of 2 cm side when containing water / 2 + size of 3 cm side when containing water / 3) × 100/2
Shrinkage rate = (size of 2 cm side when dried / size of 2 cm side when dried / 3) × 100/2
Swelling shrinkage amount = (swelling rate−100) + (100−shrinkage rate)

[Measurement of proton conductivity]
The AC resistance was obtained by pressing a platinum wire (f = 0.5 mm) on the surface of a strip-shaped sample film having a width of 5 mm, holding the sample in a constant temperature and humidity device, and measuring AC impedance between the platinum wires. . That is, the impedance at AC 10 kHz was measured in an environment of 85 ° C. and relative humidity 90%. A chemical impedance measurement system manufactured by NF Circuit Design Co., Ltd. was used as the resistance measurement device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. The specific resistance of the membrane was calculated from the line-to-line distance and the resistance gradient, and the proton conductivity was calculated from the reciprocal of the specific resistance.
Specific resistance R (Ω · cm) = 0.5 (cm) × film thickness (cm) × resistance-to-resistance gradient (Ω / cm)

<Synthesis Example 1-1>
3,5-Dichlorobenzenesulfonyl chloride (114.65 g, 467 mmol) was added to a solution of neopentyl alcohol (45.30 g, 514 mmol) in pyridine (300 mL) over 15 minutes while stirring little by little. During this time, the reaction temperature was kept at 18-20 ° C. The reaction mixture was stirred for an additional 30 minutes with cooling, then ice-cold 10% HCl (1600 mL) was added. Insoluble components in water were extracted with 700 mL of ethyl acetate, washed twice with 1N HCl (700 mL each), twice with 5% NaHCO ₃ (700 mL each) and dried over MgSO ₄ . The solvent was removed using a rotary dryer and the residue was recrystallized from 500 mL methanol. As a result, pure (purity exceeding 99% by 1H NMR) neopentyl 3,5-dichlorobenzenesulfonate (compound represented by the following formula (30-1)) was obtained as glossy colorless crystals. The yield was 105.98 g, and the yield was 76%.

＜合成例１−２＞
２、５−ジクロロベンゼンスルホニルクロライド（１１４．６５ｇ、４６７ｍｍｏｌ）を、ネオペンチルアルコール（４５．３０ｇ、５１４ｍｍｏｌ）のピリジン（３００ｍＬ）溶液に、少量ずつ攪拌しながら１５分かけて添加した。この間、反応温度は１８〜２０℃に保った。反応混合物を、冷却しながらさらに３０分攪拌した後、氷冷した１０％ ＨＣｌ（１６００ｍＬ）を添加した。水に不溶の成分を７００ｍＬの酢酸エチルで抽出し、１Ｎ ＨＣｌで２回（各７００ｍＬ）洗浄し、５％ ＮａＨＣＯ₃で２回（各７００ｍＬ）洗浄し、ＭｇＳＯ₄で乾燥させた。回転乾燥機を用いて溶媒を除去し、残渣を５００ｍＬのメタノールから再結晶させた。その結果、純粋な（１Ｈ ＮＭＲで９９％を超える純度）２、５−ジクロロベンゼンスルホン酸ネオペンチル（下記式（３０−２で表される化合物））を、光沢のある無色の結晶として得た。収量は９９．９３ｇ、収率は７２％であった。

<Synthesis Example 1-2>
2,5-Dichlorobenzenesulfonyl chloride (114.65 g, 467 mmol) was added to a solution of neopentyl alcohol (45.30 g, 514 mmol) in pyridine (300 mL) over 15 minutes with stirring. During this time, the reaction temperature was kept at 18-20 ° C. The reaction mixture was stirred for an additional 30 minutes with cooling, then ice-cold 10% HCl (1600 mL) was added. Insoluble components in water were extracted with 700 mL of ethyl acetate, washed twice with 1N HCl (700 mL each), twice with 5% NaHCO ₃ (700 mL each) and dried over MgSO ₄ . The solvent was removed using a rotary dryer and the residue was recrystallized from 500 mL methanol. As a result, pure (purity exceeding 99% by 1H NMR) neopentyl 2,5-dichlorobenzenesulfonate (compound represented by the following formula (30-2)) was obtained as glossy colorless crystals. The yield was 99.93 g, and the yield was 72%.

＜合成例１−３＞
攪拌機、冷却管を備えた３Ｌの三口フラスコに、クロロスルホン酸（２３３．０ｇ、２ｍｏｌ）を加え、続いて２，５−ジクロロベンゾフェノン（１００．４ｇ、４００ｍｍｏｌ）を加え、１００℃のオイルバスで８時間反応させた。所定時間後、反応液を砕氷（１０００ｇ）にゆっくりと注ぎ、酢酸エチルで抽出した。有機層を食塩水で洗浄、硫酸マグネシウムで乾燥後、酢酸エチルを留去し、淡黄色の粗結晶（３−（２，５−ジクロロベンゾイル）ベンゼンスルホン酸クロリド）を得た。粗結晶は精製することなく、そのまま次工程に用いた。

<Synthesis Example 1-3>
Chlorosulfonic acid (233.0 g, 2 mol) was added to a 3 L three-necked flask equipped with a stirrer and a condenser, followed by 2,5-dichlorobenzophenone (100.4 g, 400 mmol), and an oil bath at 100 ° C. The reaction was allowed for 8 hours. After a predetermined time, the reaction solution was slowly poured onto crushed ice (1000 g) and extracted with ethyl acetate. The organic layer was washed with brine and dried over magnesium sulfate, and then ethyl acetate was distilled off to obtain pale yellow crude crystals (3- (2,5-dichlorobenzoyl) benzenesulfonic acid chloride). The crude crystals were used in the next step without purification.

  2,2-Dimethyl-1-propanol (neopentyl alcohol) (38.8 g, 440 mmol) was added to 300 ml of pyridine and cooled to about 10 ° C. The crude crystals obtained above were gradually added thereto over about 30 minutes. After the total amount was added, the reaction was further stirred for 30 minutes. After the reaction, the reaction solution was poured into 1000 ml of aqueous hydrochloric acid, and the precipitated solid was collected. The obtained solid was dissolved in ethyl acetate, washed with aqueous sodium hydrogen carbonate solution and brine, dried over magnesium sulfate, and then ethyl acetate was distilled off to obtain crude crystals. This was recrystallized from methanol to obtain white crystals of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate (30-3), which was the target product.

［実施例１］
＜スルホン酸基を有しない構造単位の合成＞
攪拌機、温度計、Ｄｅａｎ−ｓｔａｒｋ管、窒素導入管、冷却管をとりつけた１Ｌの三口フラスコに、ビス（４−クロロフェニル）スルホン７５．２ｇ（０．２６２ｍｏｌ）、ｔｅｒｔ−ブチルハイドロキノン３９．６ｇ（０．２３８ｍｏｌ）、炭酸カリウム４２．８ｇ（０．３１０ｍｏｌ）をはかりとった。窒素置換後、スルホラン３００ｍＬ、トルエン１５０ｍＬを加えて攪拌した。オイルバスで反応液を１５０℃で加熱還流させた。反応によって生成する水はＤｅａｎ−ｓｔａｒｋ管にトラップした。３時間後、水の生成がほとんど認められなくなったところで、トルエンをＤｅａｎ−ｓｔａｒｋ管から系外に除去した。徐々に反応温度を１８０から１９０℃に上げ、３時間攪拌を続けた後、ビス（４−クロロフェニル）スルホン２０．４ｇ（０．０７１ｍｏｌ）を加え、さらに５時間反応させた。

[Example 1]
<Synthesis of a structural unit having no sulfonic acid group>
To a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-stark tube, nitrogen introduction tube, and cooling tube, 75.2 g (0.262 mol) of bis (4-chlorophenyl) sulfone, 39.6 g of tert-butylhydroquinone (0 .238 mol) and 42.8 g (0.310 mol) of potassium carbonate were weighed. After nitrogen substitution, 300 mL sulfolane and 150 mL toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-stark tube out of the system. The reaction temperature was gradually raised from 180 to 190 ° C. and stirring was continued for 3 hours. Then, 20.4 g (0.071 mol) of bis (4-chlorophenyl) sulfone was added, and the reaction was further continued for 5 hours.

  The reaction solution was allowed to cool and then coagulated in 1200 mL of a methanol / 4 wt% (5/1 (volume ratio)) sulfuric acid solution. The precipitated product was filtered and stirred in water (1200 mL) at 55 ° C. for 1 hour. After filtration, the mixture was again stirred in 1200 mL of water at 55 ° C. for 1 hour. After filtration, the mixture was stirred in 1,200 mL of methanol at 55 ° C. for 1 hour, filtered, and again stirred in 1,200 mL of methanol at 55 ° C. for 1 hour and filtered. After air drying, it was vacuum dried at 80 ° C. to obtain 87.7 g (yield 90%) of the desired product. Mn measured by GPC was 6,600. It was confirmed that the obtained compound was an oligomer represented by the formula (40-1).

＜スルホン化ポリマーの合成＞
上記（３０−１）で表される化合物２８．６９ｇ（９６．６ｍｍｏｌ）と、上記（４０−１）で表される化合物２２．４５ｇ（３．４５ｍｍｏｌ）、ビス（トリフェニルホスフィン）ニッケルジクロリド２．６２ｇ（４．０ｍｍｏｌ）、トリフェニルホスフィン３．１５ｇ（１２．０ｍｍｏｌ）、亜鉛１５．６９ｇ（２４０ｍｍｏｌ）の混合物中に乾燥したジメチルアセトアミド（ＤＭＡｃ）１６０ｍＬを窒素下で加えた。

<Synthesis of sulfonated polymer>
28.69 g (96.6 mmol) of the compound represented by the above (30-1), 22.45 g (3.45 mmol) of the compound represented by the above (40-1), bis (triphenylphosphine) nickel dichloride 2 In a mixture of .62 g (4.0 mmol), triphenylphosphine 3.15 g (12.0 mmol) and zinc 15.69 g (240 mmol), 160 mL of dried dimethylacetamide (DMAc) was added under nitrogen.

  The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 290 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.

  Lithium bromide (33.54 g, 386 mmol) was added to the filtrate and reacted at an internal temperature of 100 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, it was cooled to room temperature, poured into 4 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 6200 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was a polymer including a structure represented by the following formula (50-1).

［実施例２］
ビス（４−クロロフェニル）スルホン７５．２ｇ（０．２６２ｍｏｌ）、ｔｅｒｔ−ブチルハイドロキノン３９．６ｇ（０．２３８ｍｏｌ）、炭酸カリウム４２．８ｇ（０．３１０ｍｏｌ）を、ビス（４−クロロフェニル）スルホン７５．６ｇ（０．２６３ｍｏｌ）、２，５−ジ−１，１，３，３−テトラメチルブチルハイドロキノン７９．２ｇ（０．２３７ｍｏｌ）、炭酸カリウム４２．６ｇ（０．３０８ｍｏｌ）へ変更し、ビス（４−クロロフェニル）スルホン２０．４ｇ（０．０７１ｍｏｌ）をビス（４−クロロフェニル）スルホン２２．７ｇ（０．０７９ｍｏｌ）へ変更した以外は、実施例１と同様にして下記（４０−２）で表されるオリゴマーを得た。ＧＰＣで測定したＭｎは８，４００であった。

[Example 2]
75.2 g (0.262 mol) of bis (4-chlorophenyl) sulfone, 39.6 g (0.238 mol) of tert-butylhydroquinone, 42.8 g (0.310 mol) of potassium carbonate, and 75. 6 g (0.263 mol), 2,5-di-1,1,3,3-tetramethylbutylhydroquinone 79.2 g (0.237 mol), potassium carbonate 42.6 g (0.308 mol) It is represented by the following (40-2) in the same manner as in Example 1 except that 20.4 g (0.071 mol) of 4-chlorophenyl) sulfone was changed to 22.7 g (0.079 mol) of bis (4-chlorophenyl) sulfone. Oligomer was obtained. The Mn measured by GPC was 8,400.

また、上記（３０−１）で表される化合物２８．９２ｇ（９７．３ｍｍｏｌ）と、上記（４０−２）で表される化合物２２．５７ｇ（２．６９ｍｍｏｌ）、臭化リチウム３３．８１ｇ（３８９ｍｍｏｌ）へ変更した以外は、実施例１と同様にして下記（５０−２）で表されるポリマーを得た。得られたポリマーの分子量をＧＰＣで測定した結果、イオン交換容量を表１に示す。

In addition, 28.92 g (97.3 mmol) of the compound represented by the above (30-1), 22.57 g (2.69 mmol) of the compound represented by the above (40-2), 33.81 g of lithium bromide ( The polymer represented by the following (50-2) was obtained in the same manner as in Example 1 except for changing to 389 mmol). As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

［実施例３］
ｔｅｒｔ−ブチルハイドロキノン３９．６ｇ（０．２３８ｍｏｌ）を、ｔｅｒｔ−ブチルハイドロキノン２９．７ｇ（０．１７９ｍｏｌ）、２，５−ジ−ｔｅｒｔ−ブチルハイドロキノン１３．２ｇ（０．０６０ｍｏｌ）へ変更した以外は、実施例１と同様にして下記（４０−３）で表されるオリゴマーを得た。ＧＰＣで測定したＭｎは６，８００であった。

[Example 3]
Except for changing 39.6 g (0.238 mol) of tert-butylhydroquinone to 29.7 g (0.179 mol) of tert-butylhydroquinone and 13.2 g (0.060 mol) of 2,5-di-tert-butylhydroquinone. Then, an oligomer represented by the following (40-3) was obtained in the same manner as in Example 1. Mn measured by GPC was 6,800.

また、上記（３０−１）で表される化合物２８．７４ｇ（９６．７ｍｍｏｌ）と、上記（４０−３）で表される化合物２２．４８ｇ（３．３１ｍｍｏｌ）、臭化リチウム３３．５９ｇ（３８７ｍｍｏｌ）へ変更した以外は、実施例１と同様にして下記（５０−３）で表されるポリマーを得た。得られたポリマーの分子量をＧＰＣで測定した結果、イオン交換容量を表１に示す。

In addition, 28.74 g (96.7 mmol) of the compound represented by the above (30-1), 22.48 g (3.31 mmol) of the compound represented by the above (40-3), 33.59 g of lithium bromide ( Except for changing to 387 mmol), a polymer represented by the following (50-3) was obtained in the same manner as in Example 1. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

［実施例４］
ｔｅｒｔ−ブチルハイドロキノン３９．６ｇ（０．２３８ｍｏｌ）を、ｔｅｒｔ−ブチルハイドロキノン２９．７ｇ（０．１７９ｍｏｌ）、２，５−ジ−１，１，３，３−テトラメチルブチルハイドロキノン１９．９ｇ（０．０６０ｍｏｌ）へ変更した以外は、実施例１と同様にして下記（４０−４）で表されるオリゴマーを得た。ＧＰＣで測定したＭｎは７，２００であった。

[Example 4]
tert-Butylhydroquinone (39.6 g, 0.238 mol), tert-butylhydroquinone (29.7 g, 0.179 mol), 2,5-di-1,1,3,3-tetramethylbutylhydroquinone (19.9 g) (0 The oligomer represented by the following (40-4) was obtained in the same manner as in Example 1 except for changing to .060 mol). The Mn measured by GPC was 7,200.

また、上記（３０−１）で表される化合物２８．７９ｇ（９６．９ｍｍｏｌ）と、上記（４０−４）で表される化合物２２．５０ｇ（３．１３ｍｍｏｌ）、臭化リチウム３３．６５ｇ（３８８ｍｍｏｌ）へ変更した以外は、実施例１と同様にして下記（５０−４）で表されるポリマーを得た。得られたポリマーの分子量をＧＰＣで測定した結果、イオン交換容量を表１に示す。

In addition, 28.79 g (96.9 mmol) of the compound represented by the above (30-1), 22.50 g (3.13 mmol) of the compound represented by the above (40-4), 33.65 g of lithium bromide ( Except for changing to 388 mmol), a polymer represented by the following (50-4) was obtained in the same manner as in Example 1. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

［実施例５］
上記（３０−２）で表される化合物２８．７４ｇ（９６．７ｍｍｏｌ）と、上記（４０−３）で表される化合物２２．４８ｇ（３．３１ｍｍｏｌ）、臭化リチウム３３．５９ｇ（３８７ｍｍｏｌ）へ変更した以外は、実施例１と同様にして下記（５０−５）で表されるポリマーを得た。得られたポリマーの分子量をＧＰＣで測定した結果、イオン交換容量を表１に示す。

[Example 5]
28.74 g (96.7 mmol) of the compound represented by (30-2) above, 22.48 g (3.31 mmol) of the compound represented by (40-3) above, 33.59 g (387 mmol) of lithium bromide A polymer represented by the following (50-5) was obtained in the same manner as in Example 1 except for changing to As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

［実施例６］
上記（３０−３）で表される化合物３９．２４ｇ（９７．８ｍｍｏｌ）と、上記（４０−３）で表される化合物１６．６２ｇ（２．２２ｍｍｏｌ）、ビス（トリフェニルホスフィン）ニッケルジクロリド２．６２ｇ（４．０ｍｍｏｌ）、トリフェニルホスフィン３．１５ｇ（１２.０ｍｍｏｌ）、亜鉛１５．６９ｇ（２４０ｍｍｏｌ）の混合物中に乾燥したジメチルアセトアミド（ＤＭＡｃ）１８０ｍＬを窒素下で加えた。

[Example 6]
39.24 g (97.8 mmol) of the compound represented by the above (30-3), 16.62 g (2.22 mmol) of the compound represented by the above (40-3), bis (triphenylphosphine) nickel dichloride 2 In a mixture of .62 g (4.0 mmol), triphenylphosphine 3.15 g (12.0 mmol), zinc 15.69 g (240 mmol), 180 mL of dried dimethylacetamide (DMAc) was added under nitrogen.

  The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 270 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.

  To the filtrate, 29.72 g (342 mmol) of lithium bromide was added and reacted at an internal temperature of 120 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, it was cooled to room temperature, poured into 4 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 6800 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was a polymer including a structure represented by the following formula (50-6).

［比較例１］
＜スルホン酸基を有しない構造単位の合成＞
攪拌機、温度計、Ｄｅａｎ−ｓｔａｒｋ管、窒素導入管、冷却管をとりつけた１Ｌの三口フラスコに、ビス（４−クロロフェニル）スルホン１４９．３ｇ（０．５２ｍｏｌ）、ビス（４−ヒドロキシフェニル）スルホン１２０．１ｇ（０．４８ｍｏｌ）、炭酸カリウム８５．６ｇ（０．６２ｍｏｌ）をはかりとった。窒素置換後、スルホラン７００ｍＬ、トルエン３５０ｍＬを加えて攪拌した。オイルバスで反応液を１５０℃で加熱還流させた。反応によって生成する水はＤｅａｎ−ｓｔａｒｋ管にトラップした。３時間後、水の生成がほとんど認められなくなったところで、トルエンをＤｅａｎ−ｓｔａｒｋ管から系外に除去した。徐々に反応温度を１８０から１９０℃に上げ、３時間攪拌を続けた後、ビス（４−クロロフェニル）スルホン４０．２ｇ（０．１４ｍｏｌ）を加え、さらに５時間反応させた。

[Comparative Example 1]
<Synthesis of a structural unit having no sulfonic acid group>
Into a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-stark tube, nitrogen introduction tube, and cooling tube, 149.3 g (0.52 mol) of bis (4-chlorophenyl) sulfone, bis (4-hydroxyphenyl) sulfone 120 0.1 g (0.48 mol) and potassium carbonate 85.6 g (0.62 mol) were weighed. After substitution with nitrogen, 700 mL of sulfolane and 350 mL of toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-stark tube out of the system. The reaction temperature was gradually raised from 180 to 190 ° C. and stirring was continued for 3 hours. Then, 40.2 g (0.14 mol) of bis (4-chlorophenyl) sulfone was added, and the reaction was further continued for 5 hours.

  The reaction solution was allowed to cool and then coagulated in 2400 mL of a methanol / 4 wt% (5/1 (volume ratio)) sulfuric acid solution. The precipitated product was filtered and stirred in 2400 mL of water at 55 ° C. for 1 hour. After filtration, the mixture was again stirred in 2400 mL of water at 55 ° C. for 1 hour. After filtration, the mixture was stirred in methanol (2401 mL) at 55 ° C. for 1 hour, filtered, and again stirred in methanol (2400 mL) at 55 ° C. for 1 hour and filtered. After air drying, it was vacuum dried at 80 ° C. to obtain 187.6 g (yield 80%) of the target product. The Mn measured by GPC was 8,500. It was confirmed that the obtained compound was an oligomer represented by the formula (40-5).

＜スルホン化ポリマーの合成＞
上記（３０−２）で表される化合物２８．９０ｇ（９７．３ｍｍｏｌ）と、上記（４０−５）で表される化合物２３．３９ｇ（２．７５ｍｍｏｌ）、ビス（トリフェニルホスフィン）ニッケルジクロリド２．６２ｇ（４．０ｍｍｏｌ）、トリフェニルホスフィン３．１５ｇ（１２．０ｍｍｏｌ）、亜鉛１５．６９ｇ（２４０ｍｍｏｌ）の混合物中に乾燥したジメチルアセトアミド（ＤＭＡｃ）１６６ｍＬを窒素下で加えた。

<Synthesis of sulfonated polymer>
28.90 g (97.3 mmol) of the compound represented by the above (30-2), 23.39 g (2.75 mmol) of the compound represented by the above (40-5), bis (triphenylphosphine) nickel dichloride 2 166 mL of dried dimethylacetamide (DMAc) was added under nitrogen to a mixture of .62 g (4.0 mmol), 3.15 g (12.0 mmol) of triphenylphosphine, and 15.69 g (240 mmol) of zinc.

  The reaction system was heated with stirring (finally heated to 79 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 200 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filter aid.

  Lithium bromide (38.01 g, 438 mmol) was added to the filtrate, and the mixture was reacted at an internal temperature of 120 ° C. for 7 hours under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, poured into 5.0 L of water and solidified. The coagulum was immersed in acetone, filtered and washed. The washed product was washed while being stirred with 6500 g of 1N sulfuric acid. After filtration, the product was washed with ion exchanged water until the pH of the washing solution became 5 or higher. The washed solid was dried with a hot air dryer at 80 ° C. to obtain 35.5 g (yield 92.4%) of the target polymer. As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1. The obtained polymer was a polymer including a structure represented by the following formula (50-7).

［比較例２］
ｔｅｒｔ−ブチルハイドロキノン３９．６ｇ（０．２３８ｍｏｌ）を、２，２−ビス（４−ヒドロキシフェニル）−１，１，１，３，３，３−ヘキサフルオロプロパン８０．１ｇ（０．２３８ｍｏｌ）へ変更した以外は、実施例１と同様にして下記（４０−６）で表されるオリゴマーを得た。ＧＰＣで測定したＭｎは８，４００であった。

[Comparative Example 2]
39.6 g (0.238 mol) of tert-butylhydroquinone is converted to 80.1 g (0.238 mol) of 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane. Except having changed, the oligomer represented by the following (40-6) was obtained in the same manner as in Example 1. The Mn measured by GPC was 8,400.

また、上記（３０−３）で表される化合物３９．４１ｇ（９８．２ｍｍｏｌ）と、上記（４０−６）で表される化合物１３．４９ｇ（１．８０ｍｍｏｌ）、臭化リチウム２９．８５ｇ（３４４ｍｍｏｌ）へ変更した以外は、実施例６と同様にして下記（５０−８）で表されるポリマーを得た。得られたポリマーの分子量をＧＰＣで測定した結果、イオン交換容量を表１に示す。

In addition, 39.41 g (98.2 mmol) of the compound represented by the above (30-3), 13.49 g (1.80 mmol) of the compound represented by the above (40-6), 29.85 g of lithium bromide ( The polymer represented by the following (50-8) was obtained in the same manner as in Example 6 except for changing to 344 mmol). As a result of measuring the molecular weight of the obtained polymer by GPC, the ion exchange capacity is shown in Table 1.

表１に示すように、特定の構造を用いることによりプロトン伝導度が高く、かつ熱水時の膨潤および乾燥時の収縮を抑制することが出来る。

As shown in Table 1, by using a specific structure, proton conductivity is high, and swelling during hot water and shrinkage during drying can be suppressed.

Claims (10)

Having a polymer segment (A) having a sulfonic acid group and a polymer segment (B) having substantially no sulfonic acid group,
The polymer segment (A) having the sulfonic acid group has a structure represented by the following formula (3-3), and the polymer segment (B) having substantially no sulfonic acid group is represented by the following formula (1). An aromatic copolymer having the structural unit represented.

In the above formula (3-3) , each R ¹ is independently a halogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms. , A represents an integer of 0 to 3, and k represents an integer of 1 to 4-a. The plurality of R ¹ may be the same or different. )

(In the above formula (1), each R ¹ is independently a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms. 1-1) or a structural unit represented by the following formula (1-2), at least one of the plurality of L is a structural unit represented by the following formula (1-1), and a is Each independently represents an integer of 0 to 4, and p represents an integer of 2 to 200. The plurality of R ¹ , a and L may be the same or different.

(In the formula (1-1), each A is independently —O— or —S—, and each R ² is independently a hydrocarbon group having 1 to 20 carbon atoms, or 1 carbon atom. To 20 halogenated hydrocarbon groups, each W ¹ independently represents a halogen atom, b represents an integer of 1 to 4, and l represents an integer of 0 to 3. However, b + l is 4 or less. .)

(In the formula (1-2), A is independently, -O- or -S-, D is a direct bond, -O -, - S -, - CO -, - SO 2 -, -SO -, - CONH -, - COO -, - (CF 2) i - (i is an integer of 1 to _{10), - (CH 2) j} - (j is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), at least one structure selected from the group consisting of a cyclohexylidene group and a fluorenylidene group R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms, and W ² and W ³ are each independently A halogen atom, c and d are integers of 0 to 4, m and n are integers of 0 to 4, and q is an integer of 0 to 4, provided that When q = 0, d is 0. Also, c + m and d + n are 4 or less.) The number average molecular weight of polystyrene conversion of the precursor represented by the following formula (1 ') for deriving the polymer segment (B) having no sulfonic acid group is 1,000 to 50,000. Aromatic copolymer.

(In the above formula (1 ′), R ¹ , L, a, and p are the same as in formula (1), and Z ¹ is selected from a halogen atom, a nitro group, —SO ₂ CH ₃ and —SO ₂ CF _3. Represents an atom or group.   The aromatic copolymer according to claim 1 or 2, wherein in the above formula (1), p is 2 to 150.   The structural unit represented by the above formula (1-1) and the structural unit represented by the above formula (1-2) in a molar ratio (1-1) :( 1-2) at a ratio of 100: 0 to 50:50. The aromatic copolymer according to any one of claims 1 to 3. The structural unit represented by the above formula (1-1) is a molar ratio of the structural unit represented by the following formula (1-3) and the structural unit represented by the following formula (1-4): (1-3) :( 1 The aromatic copolymer according to any one of claims 1 to 4, which is contained at a ratio of 10:90 to 90:10 in -4).

(In the above formula, R ² , A, W ¹ , and l have the same meanings as in the above formula (1-1), and e represents 1 or 3)

(In the above formula, R ² , A, W ¹ , and l have the same meanings as in the above formula (1-1), and f represents 2 or 4). The aromatic copolymer according to any one of claims 1 to 4, wherein the polymer segment (A) having a sulfonic acid group has a structural unit represented by the following formula (3).

(In the above formula, Ar ¹¹ , Ar ¹² , and Ar ¹³ are each independently at least one selected from the group consisting of a benzene ring, a condensed aromatic ring, and a nitrogen-containing heterocyclic ring, which may be substituted with a fluorine atom. Y represents a divalent group having a structure, Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _u — (u is an integer of 1 to 10; Z) represents —O—, —S—, direct bond, —CO—, —SO ₂ —, —SO—, — (CH ₂ ), or —C (CF ₃ ) ₂ — or a direct bond. _l - (l is an integer of 1 to 10) or -C (CH _{3) 2,} - shown .R ²² is a direct _{bond, -O (CH 2) p -} , - O (CF 2) p - , - (CH _{2) p} - or - (CF _{2) p} - are shown (p shows an integer of 1 to 12) .R ^23, R ²⁴ each independently represent a hydrogen atom, alk Metal atom or an aliphatic hydrocarbon group, a heterocyclic group containing an alicyclic, an oxygen. However, .x ¹ is at least one hydrogen atom of all R ²³ and R ²⁴ contained in the above formula Is an integer from 0 to 4, x ² is an integer from 1 to 5, a is an integer from 0 to 1, and b is an integer from 0 to ^3. )   A polymer electrolyte comprising the aromatic copolymer according to any one of claims 1 to 6.   A proton conducting membrane comprising the aromatic copolymer according to any one of claims 1 to 7.   A membrane-electrode assembly comprising the polymer electrolyte membrane according to claim 7 and a catalyst layer and a gas diffusion layer in contact with both sides of the polymer electrolyte membrane.   A polymer electrolyte fuel cell comprising the membrane-electrode assembly according to claim 9.