JP2005135652A - High polymer electrolyte composition and proton conducting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high polymer electrolyte film having enhanced durability and weather resistance. <P>SOLUTION: This high polymer electrolyte composition contains (a) a high polymer electrolyte and (b) an ultraviolet absorbent. The composition is an aromatic polymer having a sulfonic acid group, and the aromatic polymer having the sulfonic group is polyallylene. A benzophenone based absorbent, a benzotriazole based absorbent, a cyanoacrylate-based absorbent, and a nickel-based absorbent are available for the ultraviolet absorbent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a polymer electrolyte membrane containing an ultraviolet absorber.

The polymer electrolyte membrane is a main material constituting the fuel cell and is required to have excellent power generation performance. At the same time, durability and weather resistance are raised as one of the important performances required for the polymer electrolyte membrane.
In particular, polymers having sulfonic acid groups introduced into aromatic polymers such as polyarylene can be produced at low cost, have excellent thermal stability, have high proton conductivity and water resistance, and are polymer electrolyte membranes. However, it is not sufficient in terms of durability and weather resistance. One of the causes that cause a decrease in durability and weather resistance is a decrease in mechanical strength due to breakage of a polymer chain by ultraviolet rays in a manufacturing or assembly process or in an environment during storage. This problem is particularly remarkable when the polyelectrolyte is an aromatic polymer, which is because these polymers easily absorb ultraviolet rays in a harmful wavelength region.
JP2002-220530

The present invention has been made to solve the above problems, and provides a polymer electrolyte membrane having improved durability and weather resistance by adding an ultraviolet absorber to the polymer electrolyte membrane. It is.

The polymer electrolyte used in the polymer electrolyte membrane of the present invention is preferably a polymer having a sulfonic acid group or a polymer having an acidic functional group such as phosphoric acid or carboxylic acid.
Examples of the polymer having a sulfonic acid group include a sulfonated perfluorohydrocarbon polymer and a sulfonated non-perfluorohydrocarbon polymer. Examples of sulfonated non-perfluorohydrocarbon polymers include sulfonated polyarylene, sulfonated polyether, sulfonated polyetherketone, sulfonated polysulfone, sulfonated polyetheretherketone, sulfonated polybenzimidazole, and sulfonated polyimide. I can give you. These polymers are preferably aromatic polymers having an aromatic ring in the main chain.
A more preferred polymer electrolyte in the present invention is a sulfonated polyarylene.
The polyarylene having a sulfonic acid group used in the present invention will be specifically described.
(Polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group used in the present invention includes a repeating structural unit represented by the following general formula (A) and a repeating structural unit represented by the following general formula (B). It is a polymer represented by general formula (C).

式中、Ａは２価の電子吸引性基を示し、具体的には−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_ｌ−（ここで、ｌは１〜１０の整数である）、−Ｃ（ＣＦ₃）₂−などが挙げられる。Ｂは２価の電子供与基または直接結合を示し、電子供与基の具体例としては、−（ＣＨ₂）−、−Ｃ（ＣＨ₃）₂−、−Ｏ−、−Ｓ−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ―および

などが挙げられる。なお、電子吸引性基とは、ハメット（Hammett）置換基常数がフェニル基のｍ位の場合、０．０６以上、ｐ位の場合、０．０１以上の値となる基をいう。
Ａｒは−ＳＯ₃Ｈで表される置換基を有する芳香族基を示し、芳香族基として具体的にはフェニル基、ナフチル基、アントラセニル基、フェナンチル基などが挙げられる。これらの基のうち、フェニル基、ナフチル基が好ましい。
ｍは０〜１０、好ましくは０〜２の整数、ｎは０〜１０、好ましくは０〜２の整数を示し、ｋは１〜４の整数を示す。

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

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

式（Ｂ）中、Ｒ¹〜Ｒ⁸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、フッ素置換アルキル基、アリル基、アリール基およびシアノ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。
アルキル基としては、メチル基、エチル基、プロピル基、ブチル基、アミル基、ヘキシル基などが挙げられ、メチル基、エチル基などが好ましい。
フッ素置換アルキル基としては、トリフルオロメチル基、パーフルオロエチル基、パーフルオロプロピル基、パーフルオロブチル基、パーフルオロペンチル基、パーフルオロヘキシル基などが挙げられ、トリフルオロメチル基、ペンタフルオロエチル基などが好ましい。
アリル基としては、プロペニル基などが挙げられ、
アリール基としては、フェニル基、ペンタフルオロフェニル基などが挙げられる。
Ｗは単結合または２価の電子吸引性基を示し、Ｔは単結合または２価の有機基を示す。
式（Ｂ）において、ｐは０または正の整数であり、上限は通常１００、好ましくは１０〜８０である。

In formula (B), R ^{1 to} R ⁸ may be the same as or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. At least one atom or group is shown.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, and a hexyl group, and a methyl group and an ethyl group are preferable.
Examples of the fluorine-substituted alkyl group include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, trifluoromethyl group, pentafluoroethyl group, and the like. Etc. are preferable.
Examples of allyl groups include propenyl groups,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.
W represents a single bond or a divalent electron-withdrawing group, and T represents a single bond or a divalent organic group.
In the formula (B), p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.

上記において、ｐは０または正の整数であり、上限は通常１００、好ましくは１０〜８０である。
本発明で用いられるスルホン酸基を有するポリアリーレンは、式（Ａ）で表される繰り返し構成単位を０．５〜１００モル％、好ましくは１０〜９９．９９９モル％の割合で、式（Ｂ）で表される繰り返し構成単位を９９．５〜０モル％、好ましくは９０〜０．００１モル％の割合で含有している。

（スルホン酸基を有するポリアリーレンの製造方法）
スルホン酸基を有するポリアリーレンは、上記一般式（Ａ）で表される構造単位となりうるスルホン酸エステル基を有するモノマーと、上記一般式（Ｂ）で表される構造単位となりうるオリゴマーとを共重合させ、スルホン酸エステル基を有するポリアリーレンを製造し、このスルホン酸エステル基を有するポリアリーレンを加水分解して、スルホン酸エステル基をスルホン酸基に変換することにより合成することができる。
また、スルホン酸基を有する重合体は、上記一般式（Ａ）で表される骨格を有しスルホン酸基、スルホン酸エステル基を有しない構造単位と、上記一般式（Ｂ）の構造単位からなるポリアリーレンを予め合成し、この重合体をスルホン化することにより合成することもできる。
上記一般式（Ａ）の構造単位となりうるモノマー（例えば下記一般式（Ｄ）で表されるモノマー、モノマー（Ｄ）ともいう。）と、上記一般式（Ｂ）の構造単位となりうるオリゴマー（例えば下記一般式（Ｅ）で表されるオリゴマー、オリゴマー（Ｅ）ともいう。）とを共重合させてスルホン酸エステル基を有するポリアリーレンを合成する場合には、モノマー（Ｄ）としては、例えば下記一般式（Ｄ）で表されるスルホン酸エステルが用いられる。

In the above, p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
The polyarylene having a sulfonic acid group used in the present invention contains 0.5 to 100 mol%, preferably 10 to 99.999 mol% of the repeating structural unit represented by the formula (A). ) Is contained in a proportion of 99.5 to 0 mol%, preferably 90 to 0.001 mol%.

(Method for producing polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group includes a monomer having a sulfonic acid ester group that can be a structural unit represented by the general formula (A) and an oligomer that can be a structural unit represented by the general formula (B). It can be synthesized by polymerizing to produce a polyarylene having a sulfonic acid ester group, hydrolyzing the polyarylene having a sulfonic acid ester group, and converting the sulfonic acid ester group into a sulfonic acid group.
The polymer having a sulfonic acid group includes a structural unit having a skeleton represented by the general formula (A) and not having a sulfonic acid group or a sulfonic acid ester group, and a structural unit of the general formula (B). The polyarylene can be synthesized in advance and the polymer can be synthesized by sulfonation.
A monomer that can be a structural unit of the general formula (A) (for example, a monomer represented by the following general formula (D), also referred to as monomer (D)) and an oligomer that can be a structural unit of the general formula (B) (for example, In the case of synthesizing a polyarylene having a sulfonate group by copolymerizing with an oligomer represented by the following general formula (E) or oligomer (E), examples of the monomer (D) include A sulfonic acid ester represented by the general formula (D) is used.

式（Ｄ）中、Ｘはフッ素を除くハロゲン原子（塩素、臭素、ヨウ素）、−ＯＳＯ₂Ｚ（ここで、Ｚ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し、Ａ、Ｂ、Ａｒ、ｍ、ｎおよびｋは、それぞれ上記一般式（Ａ）中のＡ、Ｂ、Ａｒ、ｍ、ｎおよびｋと同義である。Ｒ^ａは炭素原子数１〜２０、好ましくは４〜２０の炭化水素基を示し、具体的には、メチル基、エチル基、ｎ−プロピル基、ｉｓｏ−プロピル基、tert-ブチル基、iso-ブチル基、ｎ−ブチル基、ｓｅｃ−ブチル基、ネオペンチル基、シクロペンチル基、ヘキシル基、シクロヘキシル基、シクロペンチルメチル基、シクロヘキシルメチル基、アダマンチル基、アダマンタンメチル基、２−エチルヘキシル基、ビシクロ［２.２.１］へプチル基、ビシクロ［２.２.１］へプチルメチル基、テトラヒドロフルフリル基、２−メチルブチル基、３,３−ジメチル−２,４−ジオキソランメチル基、シクロヘキシルメチル基、アダマンチルメチル基、ビシクロ［２.２.１］ヘプチルメチル基などの直鎖状炭化水素基、分岐状炭化水素基、脂環式炭化水素基、５員の複素環を有する炭化水素基などが挙げられる。これらのうちｎ−ブチル基、ネオペンチル基、テトラヒドロフルフリル基、シクロペンチル基、シクロヘキシル基、シクロヘキシルメチル基、アダマンチルメチル基、ビシクロ［２.２.１］ヘプチルメチル基が好ましく、さらにはネオペンチル基が好ましい。
Ａｒは−ＳＯ₃Ｒ^bで表される置換基を有する芳香族基を示し、芳香族基として具体的にはフェニル基、ナフチル基、アントラセニル基、フェナンチル基などが挙げられる。これらの基のうち、フェニル基、ナフチル基が好ましい。
置換基−ＳＯ₃Ｒ^bは、芳香族基に１個または２個以上置換しており、置換基−ＳＯ₃Ｒ^bが２個以上置換している場合には、これらの置換基は互いに同一でも異なっていてもよい。
ここで、Ｒ^bは炭素原子数１〜２０、好ましくは４〜２０の炭化水素基を示し、具体的には上記炭素原子数１〜２０の炭化水素基などが挙げられる。これらのうちｎ−ブチル基、ネオペンチル基、テトラヒドロフルフリル基、シクロペンチル基、シクロヘキシル基、シクロヘキシルメチル基、アダマンチルメチル基、ビシクロ［２.２.１］ヘプチルメチル基が好ましく、さらにはネオペンチル基が好ましい。
ｍは０〜１０、好ましくは０〜２の整数、ｎは０〜１０、好ましくは０〜２の整数を示し、ｋは１〜４の整数を示す。
式（Ｄ）で表されるスルホン酸エステルの具体例としては、以下の様な化合物が挙げられる。

In formula (D), X is an atom selected from halogen atoms other than fluorine (chlorine, bromine, iodine), —OSO ₂ Z (wherein Z represents an alkyl group, a fluorine-substituted alkyl group, or an aryl group) or A, B, Ar, m, n, and k are the same as A, B, Ar, m, n, and k in the general formula (A). R ^a represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso- Butyl group, n-butyl group, sec-butyl group, neopentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclopentylmethyl group, cyclohexylmethyl group, adamantyl group, adamantanemethyl group, 2-ethylhexyl group, bicyclo [2.2 .1] heptyl group, bicyclo [2.2.1] heptylmethyl group, tetrahydrofurfuryl group, 2-methylbutyl group, 3,3-dimethyl-2,4-dioxolanemethyl group, cyclohexylmethyl group, adamantylmethyl group A linear hydrocarbon group such as a bicyclo [2.2.1] heptylmethyl group, a branched hydrocarbon group, an alicyclic hydrocarbon group, 5 Such as a hydrocarbon group having a heterocyclic ring. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .
Ar represents an aromatic group having a substituent represented by —SO ₃ R ^b , and specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthyl group. Of these groups, a phenyl group and a naphthyl group are preferable.
The substituent —SO ₃ R ^b is substituted with one or more aromatic groups, and when two or more substituents —SO ₃ R ^b are substituted, these substituents are the same as each other. But it can be different.
Here, R ^b represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, and specific examples thereof include the hydrocarbon groups having 1 to 20 carbon atoms. Among these, an n-butyl group, neopentyl group, tetrahydrofurfuryl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, adamantylmethyl group, and bicyclo [2.2.1] heptylmethyl group are preferable, and a neopentyl group is more preferable. .
m represents an integer of 0 to 10, preferably 0 to 2, n represents an integer of 0 to 10, preferably 0 to 2, and k represents an integer of 1 to 4.
Specific examples of the sulfonic acid ester represented by the formula (D) include the following compounds.

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

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、上記化合物において−ＣＯ−が−ＳＯ₂−に置き換わった化合物、上記化合物において塩素原子が臭素原子に置き換わり、かつ−ＣＯ−が−ＳＯ₂−に置き換わった化合物なども挙げられる。

オリゴマー（Ｅ）としては、例えば下記一般式（Ｅ）で表される化合物が用いられる。

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

As the oligomer (E), for example, a compound represented by the following general formula (E) is used.

式（Ｅ）中、Ｒ'およびＲ''は互いに同一でも異なっていてもよく、フッ素原子を除くハロゲン原子または−ＯＳＯ₂Ｚ（ここで、Ｚ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。）で表される基を示す。Ｚが示すアルキル基としてはメチル基、エチル基などが挙げられ、フッ素置換アルキル基としてはトリフルオロメチル基などが挙げられ、アリール基としてはフェニル基、ｐ−トリル基などが挙げられる。
Ｒ¹〜Ｒ⁸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、フッ素置換アルキル基、アリル基、アリール基およびシアノ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。
アルキル基としては、メチル基、エチル基、プロピル基、ブチル基、アミル基、ヘキシル基などが挙げられ、メチル基、エチル基などが好ましい。
フッ素置換アルキル基としては、トリフルオロメチル基、パーフルオロエチル基、パーフルオロプロピル基、パーフルオロブチル基、パーフルオロペンチル基、パーフルオロヘキシル基などが挙げられ、トリフルオロメチル基、ペンタフルオロエチル基などが好ましい。
アリル基としては、プロペニル基などが挙げられ、
アリール基としては、フェニル基、ペンタフルオロフェニル基などが挙げられる。
Ｗは単結合または２価の電子吸引性基を示し、電子吸引基としては、上述したものと同様のものが挙げられる。
Ｔは単結合または２価の有機基であって、電子吸引性基であっても電子供与基であってもよい。電子吸引性基および電子供与性基としては、上述したものと同様のものが挙げられる。
ｐは０または正の整数であり、上限は通常１００、好ましくは１０〜８０である。
上記一般式（Ｅ）で表される化合物として具体的には、ｐ＝０の場合、例えば４,４'−ジクロロベンゾフェノン、４,４'−ジクロロベンズアニリド、ビス（クロロフェニル）ジフルオロメタン、２,２−ビス（４−クロロフェニル）ヘキサフルオロプロパン、４−クロロ安息香酸−４−クロロフェニル、ビス（４−クロロフェニル）スルホキシド、ビス（４−クロロフェニル）スルホン、２，６−ジクロロベンゾニトリル、９，９−ビス（４−ヒドロキシフェニル）フルオレンが挙げられる。これらの化合物において塩素原子が臭素原子またはヨウ素原子に置き換わった化合物、さらにこれらの化合物において４位に置換したハロゲン原子の少なくとも１つ以上が３位に置換した化合物などが挙げられる。
またｐ＝１の場合、上記一般式（Ｅ）で表される具体的な化合物としては、例えば４,４'−ビス（４−クロロベンゾイル）ジフェニルエーテル、４,４'−ビス（４−クロロベンゾイルアミノ）ジフェニルエーテル、４,４'−ビス（４−クロロフェニルスルホニル）ジフェニルエーテル、４,４'−ビス（４−クロロフェニル）ジフェニルエーテルジカルボキシレート、４,４'−ビス〔（４−クロロフェニル）−１,１,１,３,３,３−ヘキサフルオロプロピル〕ジフェニルエーテル、４,４'−ビス〔（４−クロロフェニル）テトラフルオロエチル〕ジフェニルエーテル、これらの化合物において塩素原子が臭素原子またはヨウ素原子に置き換わった化合物、さらにこれらの化合物において４位に置換したハロゲン原子が３位に置換した化合物、さらにこれらの化合物においてジフェニルエーテルの４位に置換した基の少なくとも１つが３位に置換した化合物などが挙げられる。
さらに上記一般式（Ｅ）で表される化合物としては、２,２−ビス［４−｛４−（４−クロロベンゾイル）フェノキシ｝フェニル］−１,１,１,３,３,３−ヘキサフルオロプロパン、ビス［４−｛４−（４−クロロベンゾイル）フェノキシ｝フェニル］スルホン、および下記式で表される化合物が挙げられる。

In the formula (E), R ′ and R ″ may be the same as or different from each other, and a halogen atom or —OSO ₂ Z excluding a fluorine atom (where Z is an alkyl group, a fluorine-substituted alkyl group or an aryl group) The group represented by this is shown. Examples of the alkyl group represented by Z include a methyl group and an ethyl group, examples of the fluorine-substituted alkyl group include a trifluoromethyl group, and examples of the aryl group include a phenyl group and a p-tolyl group.
R ^{1 to} R ⁸ may be the same or different from each other, and are at least one atom selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group, or Indicates a group.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, and a hexyl group, and a methyl group and an ethyl group are preferable.
Examples of the fluorine-substituted alkyl group include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, trifluoromethyl group, pentafluoroethyl group, and the like. Etc. are preferable.
Examples of allyl groups include propenyl groups,
Examples of the aryl group include a phenyl group and a pentafluorophenyl group.
W represents a single bond or a divalent electron-withdrawing group, and examples of the electron-withdrawing group include those described above.
T is a single bond or a divalent organic group, and may be an electron-withdrawing group or an electron-donating group. Examples of the electron-withdrawing group and the electron-donating group include the same groups as described above.
p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
Specifically, as the compound represented by the general formula (E), when p = 0, for example, 4,4′-dichlorobenzophenone, 4,4′-dichlorobenzanilide, bis (chlorophenyl) difluoromethane, 2, 2-bis (4-chlorophenyl) hexafluoropropane, 4-chlorobenzoic acid-4-chlorophenyl, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile, 9,9- Bis (4-hydroxyphenyl) fluorene is mentioned. In these compounds, compounds in which a chlorine atom is replaced with a bromine atom or an iodine atom, and compounds in which at least one of halogen atoms substituted in the 4-position in these compounds are substituted in the 3-position are exemplified.
When p = 1, examples of the specific compound represented by the general formula (E) include 4,4′-bis (4-chlorobenzoyl) diphenyl ether and 4,4′-bis (4-chlorobenzoyl). Amino) diphenyl ether, 4,4′-bis (4-chlorophenylsulfonyl) diphenyl ether, 4,4′-bis (4-chlorophenyl) diphenyl ether dicarboxylate, 4,4′-bis [(4-chlorophenyl) -1,1 , 1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4′-bis [(4-chlorophenyl) tetrafluoroethyl] diphenyl ether, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom in these compounds, Further, in these compounds, compounds in which the halogen atom substituted in the 4-position is substituted in the 3-position, At least one group obtained by substituting at the 4-position of diphenyl ether in et compounds but include compounds substituted at the 3-position.
Furthermore, the compound represented by the general formula (E) is 2,2-bis [4- {4- (4-chlorobenzoyl) phenoxy} phenyl] -1,1,1,3,3,3-hexa. Examples thereof include fluoropropane, bis [4- {4- (4-chlorobenzoyl) phenoxy} phenyl] sulfone, and compounds represented by the following formulae.

上記一般式（Ｅ）で表される化合物は、例えば以下に示す方法で合成することができる。
まず電子吸引性基で連結されたビスフェノールを対応するビスフェノールのアルカリ金属塩とするために、Ｎ−メチル−２−ピロリドン、Ｎ,Ｎ-ジメチルアセトアミド、スルホラン、ジフェニルスルホン、ジメチルスルホキサイドなどの誘電率の高い極性溶媒中でリチウム、ナトリウム、カリウムなどのアルカリ金属、水素化アルカリ金属、水酸化アルカリ金属、アルカリ金属炭酸塩などを加える。
通常、アルカリ金属はフェノールの水酸基に対し、過剰気味で反応させ、通常、１．１〜２倍当量を使用する。好ましくは、１．２〜１．５倍当量の使用である。この際、ベンゼン、トルエン、キシレン、ヘキサン、シクロヘキサン、オクタン、クロロベンゼン、ジオキサン、テトラヒドロフラン、アニソール、フェネトールなどの水と共沸する溶媒を共存させて、電子吸引性基で活性化されたフッ素、塩素等のハロゲン原子で置換された芳香族ジハライド化合物、例えば、４,４'−ジフルオロベンゾフェノン、４,４'−ジクロロベンゾフェノン、４,４'−クロロフルオロベンゾフェノン、ビス（４−クロロフェニル）スルホン、ビス（４−フルオロフェニル）スルホン、４−フルオロフェニル−４'−クロロフェニルスルホン、ビス（３−ニトロ−４−クロロフェニル）スルホン、２,６−ジクロロベンゾニトリル、２,６−ジフルオロベンゾニトリル、ヘキサフルオロベンゼン、デカフルオロビフェニル、２,５−ジフルオロベンゾフェノン、１,３−ビス（４−クロロベンゾイル）ベンゼンなどを反応させる。反応性から言えば、フッ素化合物が好ましいが、次の芳香族カップリング反応を考慮した場合、末端が塩素原子となるように芳香族求核置換反応を組み立てる必要がある。活性芳香族ジハライドはビスフェノールに対し、２〜４倍モル、好ましくは２．２〜２．８倍モルの使用である。芳香族求核置換反応の前に予め、ビスフェノールのアルカリ金属塩としていてもよい。反応温度は６０〜３００℃で、好ましくは８０〜２５０℃の範囲である。反応時間は１５分〜１００時間、好ましくは１時間〜２４時間の範囲である。最も好ましい方法としては、下記式で示される活性芳香族ジハライドとして反応性の異なるハロゲン原子を一個ずつ有するクロロフルオロ体を用いることであり、フッ素原子が優先してフェノキシドと求核置換反応が起きるので、目的の活性化された末端クロロ体を得るのに好都合である。

The compound represented by the general formula (E) can be synthesized, for example, by the method shown below.
First, in order to convert the bisphenol linked with an electron-withdrawing group into the corresponding alkali metal salt of bisphenol, dielectrics such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenylsulfone, dimethylsulfoxide, etc. Add an alkali metal such as lithium, sodium or potassium, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate or the like in a polar solvent having a high rate.
Usually, the alkali metal is reacted in excess with respect to the hydroxyl group of phenol, and usually 1.1 to 2 times equivalent is used. Preferably, 1.2 to 1.5 times equivalent is used. In this case, fluorine, chlorine, etc. activated with an electron-withdrawing group in the presence of azeotropic solvent such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole, phenetole, etc. Aromatic halogen-substituted aromatic dihalide compounds such as 4,4′-difluorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-chlorofluorobenzophenone, bis (4-chlorophenyl) sulfone, bis (4 -Fluorophenyl) sulfone, 4-fluorophenyl-4'-chlorophenylsulfone, bis (3-nitro-4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, hexafluorobenzene, deca Fluorobiphenyl, , 5-difluorobenzophenone, 1,3-bis (4-chlorobenzoyl) reacting benzene. In terms of reactivity, a fluorine compound is preferable, but in consideration of the following aromatic coupling reaction, it is necessary to assemble an aromatic nucleophilic substitution reaction so that the terminal is a chlorine atom. The active aromatic dihalide is used in an amount of 2 to 4 times mol, preferably 2.2 to 2.8 times mol, of bisphenol. Prior to the aromatic nucleophilic substitution reaction, an alkali metal salt of bisphenol may be used. The reaction temperature is 60 to 300 ° C, preferably 80 to 250 ° C. The reaction time ranges from 15 minutes to 100 hours, preferably from 1 hour to 24 hours. The most preferable method is to use a chlorofluoro compound having one halogen atom having a different reactivity as the active aromatic dihalide represented by the following formula, and a nucleophilic substitution reaction with phenoxide occurs preferentially by the fluorine atom. It is convenient to obtain the desired activated terminal chloro form.

（式中、Ｗは一般式（Ｅ）に関して定義した通りである。）
または特開平２−１５９号公報に記載のように求核置換反応と親電子置換反応を組み合わせ、目的の電子吸引性基、電子供与性基からなる屈曲性化合物の合成方法がある。
具体的には電子吸引性基で活性化された芳香族ビスハライド、例えば、ビス（４−クロロフェニル）スルホンをフェノールとで求核置換反応させてビスフェノキシ置換体とする。次いで、この置換体を例えば、４−クロロ安息香酸クロリドとのフリーデルクラフト反応から目的の化合物を得る。ここで用いる電子吸引性基で活性化された芳香族ビスハライドは上記で例示した化合物が適用できる。フェノール化合物は置換されていてもよいが、耐熱性や屈曲性の観点から、無置換化合物が好ましい。なお、フェノールの置換反応にはアルカリ金属塩とするのが、好ましく、使用可能なアルカリ金属化合物は上記に例示した化合物を使用できる。使用量はフェノール１モルに対し、１．２〜２倍モルである。反応に際し、上述した極性溶媒や水との共沸溶媒を用いることができる。ビスフェノキシ化合物を塩化アルミニウム、三フッ化ホウ素、塩化亜鉛などのルイス酸のフリーデルクラフト反応の活性化剤存在下に、アシル化剤として、クロロ安息香酸クロライドを反応させる。クロロ安息香酸クロライドはビスフェノキシ化合物に対し、２〜４倍モル、好ましくは２．２〜３倍モルの使用である。フリーデルクラフト活性化剤は、アシル化剤のクロロ安息香酸などの活性ハライド化合物１モルに対し、１．１〜２倍当量使用する。反応時間は１５分〜１０時間の範囲で、反応温度は−２０℃から８０℃の範囲である。使用溶媒は、フリーデルクラフト反応に不活性な、クロロベンゼンやニトロベンゼンなどを用いることができる。
また、一般式（Ｅ）において、ｐが２以上である化合物は、例えば、一般式（Ｅ）において電子供与性基Ｔであるエーテル性酸素の供給源となるビスフェノールと、電子吸引性基Ｗである、＞Ｃ＝Ｏ、−ＳＯ₂−および＞Ｃ（ＣＦ₃）₂から選ばれる少なくとも１種の基とを組み合わせた化合物、具体的には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、２,２−ビス（４−ヒドロキシフェニル）ケトン、２,２−ビス（４−ヒドロキシフェニル）スルホンなどのビスフェノールのアルカリ金属塩と、過剰の４,４−ジクロロベンゾフェノン、ビス（４−クロロフェニル)スルホンなどの活性芳香族ハロゲン化合物との置換反応をＮ−メチル−２−ピロリドン、Ｎ,Ｎ−ジメチルアセトアミド、スルホランなどの極性溶媒存在下で前記単量体の合成手法に順次重合して得られる。
このような化合物の例示としては、下記式で表される化合物などを挙げることができる。

(Wherein, W is as defined for general formula (E).)
Alternatively, as described in JP-A-2-159, there is a method for synthesizing a flexible compound comprising a target electron-withdrawing group and electron-donating group by combining a nucleophilic substitution reaction and an electrophilic substitution reaction.
Specifically, an aromatic bishalide activated with an electron-withdrawing group, for example, bis (4-chlorophenyl) sulfone is subjected to a nucleophilic substitution reaction with phenol to obtain a bisphenoxy-substituted product. Then, the desired compound is obtained from the Friedel-Craft reaction of this substituted product with, for example, 4-chlorobenzoic acid chloride. As the aromatic bishalide activated with the electron-withdrawing group used here, the compounds exemplified above can be applied. The phenol compound may be substituted, but an unsubstituted compound is preferable from the viewpoint of heat resistance and flexibility. In addition, it is preferable to use an alkali metal salt for the phenol substitution reaction, and as the usable alkali metal compound, the compounds exemplified above can be used. The amount used is 1.2 to 2 moles per mole of phenol. In the reaction, the polar solvent described above or an azeotropic solvent with water can be used. The bisphenoxy compound is reacted with chlorobenzoic acid chloride as an acylating agent in the presence of an activator for the Friedel-Crafts reaction of Lewis acids such as aluminum chloride, boron trifluoride, and zinc chloride. Chlorobenzoic acid chloride is used in an amount of 2 to 4 times mol, preferably 2.2 to 3 times mol, of the bisphenoxy compound. The Friedel-Craft activator is used in an amount of 1.1 to 2 times equivalent to 1 mol of an active halide compound such as chlorobenzoic acid as an acylating agent. The reaction time ranges from 15 minutes to 10 hours, and the reaction temperature ranges from -20 ° C to 80 ° C. As the solvent used, chlorobenzene, nitrobenzene and the like which are inert to Friedel-Crafts reaction can be used.
Further, in the general formula (E), the compound in which p is 2 or more is, for example, a bisphenol that is a source of etheric oxygen that is the electron donating group T in the general formula (E) and an electron withdrawing group W. A compound in combination with at least one group selected from> C═O, —SO ₂ — and> C (CF ₃ ) ₂ , specifically 2,2-bis (4-hydroxyphenyl) -1 1,1,3,3,3-hexafluoropropane, alkali metal salts of bisphenols such as 2,2-bis (4-hydroxyphenyl) ketone, 2,2-bis (4-hydroxyphenyl) sulfone, and excess The substitution reaction with an active aromatic halogen compound such as 4,4-dichlorobenzophenone and bis (4-chlorophenyl) sulfone is N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane. In the presence of any polar solvent, it is obtained by sequential polymerization in the monomer synthesis method.
Examples of such compounds include compounds represented by the following formulas.

上記において、ｐは０または正の整数であり、上限は通常１００、好ましくは１０〜８０である。
本発明に係るポリアリーレン中の上記一般式（Ａ）で表される繰り返し構成単位の含有割合は、特に限定されないが、好ましくは０．５〜１００モル％、より好ましくは１０〜９９．９９９モル％である。また、本発明に係るポリアリーレン中の上記一般式（Ｂ）で表される繰り返し構成単位の含有割合は、好ましくは０〜９９．５モル％、より好ましくは０．００１〜９０モル％である。

In the above, p is 0 or a positive integer, and the upper limit is usually 100, preferably 10-80.
Although the content rate of the repeating structural unit represented by the general formula (A) in the polyarylene according to the present invention is not particularly limited, it is preferably 0.5 to 100 mol%, more preferably 10 to 99.999 mol. %. Moreover, the content ratio of the repeating structural unit represented by the general formula (B) in the polyarylene according to the present invention is preferably 0 to 99.5 mol%, more preferably 0.001 to 90 mol%. .

The polyarylene (C) having a sulfonate group is synthesized by reacting the monomer (D) and the oligomer (E) in the presence of a catalyst. The catalyst used in this case is a catalyst containing a transition metal compound. This catalyst system includes (1) a transition metal salt and a compound that becomes a ligand (hereinafter referred to as “ligand component”), or a transition metal complex in which a ligand is coordinated (copper). Salt is included), and (2) a reducing agent is an essential component, and “salt” may be added to increase the polymerization rate.
Here, as the transition metal salt, nickel compounds such as nickel chloride, nickel bromide, nickel iodide and nickel acetylacetonate; palladium compounds such as palladium chloride, palladium bromide and palladium iodide; iron chloride and iron bromide And iron compounds such as iron iodide; cobalt compounds such as cobalt chloride, cobalt bromide, and cobalt iodide. Of these, nickel chloride, nickel bromide and the like are particularly preferable.
Examples of the ligand component include triphenylphosphine, 2,2′-bipyridine, 1,5-cyclooctadiene, 1,3-bis (diphenylphosphino) propane, and the like. Of these, triphenylphosphine and 2,2′-bipyridine are preferred. The compound which is the said ligand component can be used individually by 1 type or in combination of 2 or more types.
Furthermore, as the transition metal complex in which the ligand is coordinated, for example, nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis (triphenylphosphine), nickel nitrate bis (Triphenylphosphine), nickel chloride (2,2'-bipyridine), nickel bromide (2,2'-bipyridine), nickel iodide (2,2'-bipyridine), nickel nitrate (2,2'-bipyridine) ), Bis (1,5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel, tetrakis (triphenylphosphine) palladium and the like. Of these, nickel chloride bis (triphenylphosphine) and nickel chloride (2,2′-bipyridine) are preferred.

Examples of the reducing agent that can be used in the catalyst system include iron, zinc, manganese, aluminum, magnesium, sodium, calcium, and the like. Of these, zinc, magnesium and manganese are preferred. These reducing agents can be used after being more activated by bringing them into contact with an acid such as an organic acid.
Examples of the “salt” that can be used in the above catalyst system include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, potassium fluoride, potassium chloride, potassium bromide, Examples include potassium compounds such as potassium iodide and potassium sulfate; ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetraethylammonium sulfate. Of these, sodium bromide, sodium iodide, potassium bromide, tetraethylammonium bromide, and tetraethylammonium iodide are preferred.

The proportion of each component used is usually 0.0001 to 10 moles, preferably 0.001 moles per mole of transition metal salt or transition metal complex ((D) + (E), hereinafter the same). 01-0.5 mol. When the amount is less than 0.0001 mol, the polymerization reaction may not proceed sufficiently. On the other hand, when the amount exceeds 10 mol, the molecular weight may decrease.
When a transition metal salt and a ligand component are used in the catalyst system, the ratio of the ligand component used is usually 0.1 to 100 mol, preferably 1 to 10 mol, per 1 mol of the transition metal salt. is there. When the amount is less than 0.1 mol, the catalytic activity may be insufficient. On the other hand, when the amount exceeds 100 mol, the molecular weight may decrease.

Moreover, the usage-amount of a reducing agent is 0.1-100 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 1-10 mol. If the amount is less than 0.1 mol, polymerization may not proceed sufficiently. If the amount exceeds 100 mol, purification of the resulting polymer may be difficult.
Furthermore, when using "salt", the usage-ratio is 0.001-100 mol normally with respect to the total of 1 mol of the said monomer, Preferably it is 0.01-1 mol. If it is less than 0.001 mol, the effect of increasing the polymerization rate may be insufficient, and if it exceeds 100 mol, purification of the resulting polymer may be difficult.

Examples of the polymerization solvent that can be used when the monomer (D) and the oligomer (E) are reacted include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl. -2-pyrrolidone, γ-butyrolactone, N, N′-dimethylimidazolidinone and the like. Of these, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N, N′-dimethylimidazolidinone are preferable. These polymerization solvents are preferably used after sufficiently dried.
The total concentration of the monomers in the polymerization solvent is usually 1 to 90% by weight, preferably 5 to 40% by weight.
Moreover, the superposition | polymerization temperature at the time of superposing | polymerizing is 0-200 degreeC normally, Preferably it is 50-120 degreeC. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.
The polyarylene having a sulfonic acid ester group obtained using the monomer (D) can be converted into a polyarylene having a sulfonic acid group by hydrolyzing the sulfonic acid ester group and converting it to a sulfonic acid group. .

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

The polyarylene having a sulfonic acid group includes a monomer having a skeleton similar to that of the monomer (D) represented by the general formula (D) and an oligomer represented by the general formula (E). It is also possible to synthesize a polyarylene copolymer in advance by copolymerizing (E) and sulphonate the polyarylene copolymer. In this case, after producing a polyarylene having no sulfonic acid group by a method according to the above synthesis method, a sulfonic acid group is introduced by introducing a sulfonic acid group into the polyarylene having no sulfonic acid group using a sulfonating agent. Can be obtained.
As the reaction conditions for this sulfonation, polyarylene having no sulfonic acid group can be obtained by introducing a sulfonic acid group by a conventional method using a sulfonating agent in the absence of a solvent or in the presence of a solvent. .

As a method for introducing a sulfonic acid group, for example, the polyarylene having no sulfonic acid group is known by using a known sulfonating agent such as sulfuric anhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid, sodium hydrogen sulfite and the like. [Polymer Preprints, Japan, Vol. 42, No. 3, p. 730 (1993); Polymer Preprints, Japan, Vol. 43, No. 3, p. 736 (1994); Polymer Preprints, Japan, Vol. 42, No. 7, p. 2490-2492 (1993)].
That is, as the reaction conditions for the sulfonation, the polyarylene having no sulfonic acid group is reacted with the sulfonating agent in the absence of a solvent or in the presence of a solvent. Examples of the solvent include hydrocarbon solvents such as n-hexane, ether solvents such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide, and dimethylsulfoxide, tetrachloroethane, dichloroethane, chloroform, and chloride. And halogenated hydrocarbons such as methylene. The reaction temperature is not particularly limited, but is usually −50 to 200 ° C., preferably −10 to 100 ° C. Moreover, reaction time is 0.5 to 1,000 hours normally, Preferably it is 1 to 200 hours.

The content of the repeating structural unit represented by the general formula (A) in the polyarylene having a sulfonic acid group used in the present invention is not particularly limited, but is preferably 0.5 to 100 mol%, more preferably It is 10-99.999 mol%. In addition, the content of the repeating structural unit represented by the general formula (B) in the polyarylene used in the present invention is preferably 99.5 to 0 mol%, more preferably 90 to 0.001 mol%. is there.
In the polyarylene (C) having a sulfonic acid group produced by the method as described above, the amount of the sulfonic acid group is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably 0. .8 to 2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and not practical. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered, which is not preferable.

The amount of the sulfonic acid group can be adjusted, for example, by changing the type, usage ratio, and combination of the monomer (D) and the oligomer (E).
The molecular weight of the polyarylene having a sulfonic acid group thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).
The polymer electrolyte membrane of the present invention is characterized by containing an ultraviolet absorber.
As the ultraviolet absorber used in the present invention, an ultraviolet absorber having an effect of absorbing ultraviolet rays of a specific wavelength and an agent that does not absorb ultraviolet rays but has a performance of protecting the resin from ultraviolet rays (ultraviolet stabilizer) are used. be able to.

Specific examples of such ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5) -Benzophenone ultraviolet absorbers such as benzoylphenylmethane, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl Benzotriazole, 2- (2-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) ) -5-chlorobenzotriazole, 2- (2′-hydroxy-3,5′-di-tert-amylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″) , 5 '', 6 ''-tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H- Benzotriazole-based UV absorbers such as benzotriazol-2-yl) phenol) and 2- (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, 2-ethylhexyl-2- Cyanoacrylate ultraviolet absorbers such as ano-3,3′-diphenyl acrylate and ethyl-2-cyano-3,3′-diphenyl acrylate, nickel bis (octylphenyl) sulfide, (2,2′-thiobis (4- tert-octylphenylphenolate))-n-butylamine nickel, nickel-based ultraviolet absorbers (stabilizers) such as nickel-dibutyldithiocarbamate, ADK STAB LA-77, ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67 And hindered amine UV stabilizers such as Adekastab LA-63, Adekastab LA-68, Adekastab LA-82, and Adekastab LA-87 (all of which are commercially available).
In the present invention, at least one ultraviolet absorber can be used as necessary.
In the present invention, the preferable amount of the ultraviolet absorber added to the polymer electrolyte is 0.01% by weight or more and less than 10% by weight. When the addition amount is less than 0.01% by weight, a sufficient ultraviolet absorption effect is not exhibited, and when the addition amount is 10% by weight or more, proton conductivity and mechanical properties are deteriorated.

These ultraviolet absorbers have an effect of preventing the polymer chain from being broken by harmful ultraviolet energy and preventing the polymer electrolyte membrane from being deteriorated, and improving durability and weather resistance.
The polymer electrolyte membrane of the present invention can be produced, for example, as follows.
A proton conducting membrane made of a polymer electrolyte containing an ultraviolet absorber is obtained by a casting method in which a polymer electrolyte is dissolved in an organic solvent, which is soluble in any UV absorber, cast on a substrate, and the solvent is evaporated. Can be obtained. 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 or metal is used, and preferably a thermoplastic such as a polyethylene terephthalate (PET) film. A substrate made of resin is used.

In preparing the polymer electrolyte membrane, an inorganic acid such as sulfuric acid and phosphoric acid, an organic acid containing a carboxylic acid, an appropriate amount of water, and the like may be used in addition to the solid polymer electrolyte.
When a polyarylene polymer having a sulfonic acid group is used as the polymer electrolyte, for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide And aprotic polar solvents such as dimethylurea and dimethylimidazolidinone, and N-methyl-2-pyrrolidone (hereinafter also referred to as “NMP”) is preferable from the viewpoint of solubility and solution viscosity. The aprotic polar solvent can be used alone or in combination of two or more.
In addition, as a solvent for dissolving the polyarylene polymer having a sulfonic acid group, a mixture of the above aprotic polar solvent and alcohol can also be used. Examples of the alcohol include methanol, ethanol, propyl alcohol, iso-propyl alcohol, sec-butyl alcohol, tert-butyl alcohol and the like, and methanol is particularly preferable because it has an effect of lowering the solution viscosity in a wide composition range. Alcohol can be used individually by 1 type or in combination of 2 or more types.

When a mixture of an aprotic polar solvent and an alcohol is used as the solvent, the aprotic polar solvent is 95 to 25% by weight, preferably 90 to 25% by weight, and the alcohol is 5 to 75% by weight, preferably 10 to 75% by weight (however, the total is 100% by weight). When the amount of alcohol is within the above range, the effect of lowering the solution viscosity is excellent.
The polymer concentration of the solution is usually 5 to 40% by weight, preferably 7 to 25% by weight, although it depends on the molecular weight of the polyarylene polymer having a sulfonic acid group. If it is less than 5% by weight, it is difficult to form a thick film, and pinholes are easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.
The solution viscosity is usually 2,000 to 100,000 mPa · s, preferably 3,000 to 50,000 mPa · s, although it depends on the molecular weight of the polyarylene polymer having a sulfonic acid group and the polymer concentration. It is. 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 immersing an undried film in water, it may be a batch system in which a single wafer is immersed in water, or a laminated film in a state where it is usually formed on a substrate film (for example, PET), or A continuous method may be used in which the film separated from the substrate is immersed in water and wound.
In the case of the batch method, the formation of wrinkles on the surface of the film that has been treated by a method such as placing the treated film in a frame is advantageous.
When the undried film is immersed in water, the contact ratio of water is 10 parts by weight or more, preferably 30 parts by weight or more with respect to 1 part by weight of the undried film. In order to minimize the amount of residual solvent in the resulting proton conducting membrane, it is preferable to maintain a contact ratio as large as possible. It is also effective to reduce the amount of residual solvent in the resulting polymer electrolyte membrane by changing the water used for immersion or allowing it to overflow so that the organic solvent concentration in the water is always kept below a certain level. It is. In order to suppress the in-plane distribution of the amount of the organic solvent remaining in the polymer electrolyte membrane, it is effective to homogenize the concentration of the organic solvent in water by stirring or the like.

The temperature of water when the undried film is immersed in water is preferably in the range of 5 to 80 ° C. The higher the temperature, the faster the replacement rate of the organic solvent and water, but the greater the amount of water absorbed by the film, so there is a concern that the surface state of the polymer electrolyte membrane obtained after drying will be rough. Usually, a temperature range of 10 to 60 ° C. is convenient because of the replacement speed and ease of handling.
The immersion time is usually in the range of 10 minutes to 240 hours, although depending on the initial residual solvent amount, contact ratio, and treatment temperature. Preferably, it is in the range of 30 minutes to 100 hours.
When the undried film is immersed in water and dried as described above, a polymer electrolyte membrane with a reduced amount of residual solvent is obtained. The residual solvent amount of the polymer electrolyte membrane thus obtained is usually 5%. % By weight or less.
Further, depending on the dipping conditions, the amount of the remaining solvent in the obtained polymer electrolyte membrane can be 1% by weight or less. As such conditions, for example, the contact ratio between the undried film and water is 50 parts by weight or more with respect to 1 part by weight of the undried film. There is a method of setting the time to 10 minutes to 10 hours.
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 polymer electrolyte membrane 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.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
In the examples, the sulfonic acid equivalent, molecular weight, and proton conductivity were determined as follows.
1. Sulfonic acid equivalent The polymer having the sulfonic acid group was washed with water until the water was neutral, thoroughly washed with water except for free remaining acid, dried, weighed a predetermined amount, THF / Phenolphthalein dissolved in a mixed solvent of water was used as an indicator, titration was performed using a standard solution of NaOH, and the sulfonic acid equivalent was determined from the neutralization point.
2. Measurement of molecular weight The polyarylene weight average molecular weight having no sulfonic acid group was determined by GPC using tetrahydrofuran (THF) as a solvent, and the molecular weight in terms of polystyrene was obtained. The molecular weight of the polyarylene having a sulfonic acid group was determined by GPC using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent as an eluent.
3. Tensile strength Tensile strength was measured by a tensile test at room temperature.
4). Ultraviolet irradiation test The film was irradiated with ultraviolet rays (UVA-310) for 24 hours using an ultraviolet irradiation device (QUV).

[Synthesis example]
Synthesis example 1
2,2-bis (4-hydroxyphenyl) -1,1,1,3 was added to a 1 L three-necked flask equipped with a stirrer, thermometer, cooling tube, Dean-Stark tube, and three-way cock for introducing nitrogen. , 3,3-hexafluoropropane (bisphenol AF) 67.3 g (0.20 mol), 4,4′-dichlorobenzophenone (4,4′-DCBP) 60.3 g (0.24 mol), potassium carbonate 71 .9 g (0.52 mol), N, N-dimethylacetamide (DMAc) 300 mL, and toluene 150 mL were taken and heated in an oil bath under a nitrogen atmosphere and reacted at 130 ° C. with stirring. When water produced by the reaction was azeotroped with toluene and reacted while being removed from the system with a Dean-Stark tube, almost no water was produced in about 3 hours. The reaction temperature was gradually increased from 130 to 150 ° C. Thereafter, most of the toluene was removed while gradually raising the reaction temperature to 150 ° C., and the reaction was continued at 150 for 10 hours. Then, 10.0 g (0.040 mol) of 4,4′-DCBP was added, and another 5 hours. Reacted. The resulting reaction solution was allowed to cool, and then the by-product inorganic compound precipitate was removed by filtration, and the filtrate was put into 4 L of methanol. The precipitated product was separated by filtration, collected, dried, and dissolved in 300 mL of tetrahydrofuran. This was reprecipitated in 4 L of methanol to obtain 95 g (yield 85%) of the target compound.
The weight average molecular weight in terms of polystyrene determined by GPC (THF solvent) of the obtained polymer was 11,200. Further, the obtained polymer was soluble in THF, NMP, DMAc, sulfolane and the like, Tg was 110 ° C., and thermal decomposition temperature was 498 ° C.
The obtained compound was an oligomer represented by the formula (I) (hereinafter referred to as “BCPAF oligomer”).

[Synthesis Example 2]
Preparation of polyarylene copolymer (PolyAB-SO ₃ neo-Pe) with neopentyl group as protecting group 1L three-neck equipped with a stirrer, thermometer, cooling pipe, Dean-Stark pipe, and three-way cock for introducing nitrogen In a flask, 39.58 g (98.64 mmol) of 4- [4- (2,5-dichlorobenzoyl) phenoxy] benzenesulfonate neo-pentyl (A-SO ₃ neo-Pe) and a BCPAF oligomer (Mn = 11200) 15.23 g (1.36 mmol), Ni (PPh ₃ ) ₂ Cl ₂ 1.67 g (2.55 mmol), PPh ₃ 10.49 g (40 mmol), NaI 0.45 g (3 mmol), zinc dust 15.69 g (240 mmol), 390 mL dry NMP was added under nitrogen. The reaction system was heated with stirring (finally heated to 75 ° C.) and allowed to react for 3 hours. The polymerization reaction liquid was diluted with 250 mL of THF, stirred for 30 minutes, Celite was used as a filter aid, the filter paper and the filtrate were poured into 1500 mL of a large excess of methanol, and solidified. The coagulum was collected by filtration, air-dried, redissolved in THF / NMP (200/300 mL each), and coagulated with 1500 mL of a large excess of methanol. After air drying, 47.0 g (yield 99%) of a copolymer (PolyAB-SO ₃ neo-Pe) composed of a sulfonic acid derivative protected with a target yellow fibrous neopentyl group was obtained by heat drying. The molecular weight by GPC was Mn = 47,600 and Mw = 159,000.
Thus obtained 5.1 g of PolyAB-SO ₃ neo-Pe was dissolved in 60 mL of NMP and heated to 90 ° C. A mixture of 50 mL of methanol and 8 mL of concentrated hydrochloric acid was added to the reaction system at one time. While in suspension, the reaction was allowed to proceed for 10 hours under mild reflux conditions. A distillation apparatus was installed, and excess methanol was distilled off to obtain a light green transparent solution. This solution was poured into a large amount of water / methanol (1: 1 weight ratio) to solidify the polymer, and then the polymer was washed with ion exchange water until the pH of the washing water was 6 or more. From the IR spectrum of the polymer thus obtained and the quantitative analysis of the ion exchange capacity, it was found that the sulfonic acid ester group (—SO ₃ R ^a ) was quantitatively converted to the sulfonic acid group (—SO ₃ H). .
The obtained polyarylene copolymer having a sulfonic acid group had molecular weights by GPC of Mn = 53,200 and Mw = 185,000, and the sulfonic acid equivalent was 1.9 meq / g.

[Synthesis Example 3]
(Synthesis of polyarylene copolymer)
28.1 g (2.5 mmol) of the oligomer of formula (I) obtained in Synthesis Example 1 above, 35.9 g (82.5 mmol) of 2,5-dichloro-4 ′-(4-phenoxy) phenoxybenzophenone (DCPPB) Bis (triphenylphosphine) nickel dichloride 1.67 g (2.6 mmol), sodium iodide 1.66 g (11.1 mmol), triphenylphosphine 8.92 g (34.0 mmol), zinc powder 13.3 g (204 mmol) Was placed in a flask and purged with dry nitrogen. 160 ml of N-methyl-2-pyrrolidone was added, and the mixture was heated to 80 ° C. and stirred for 4 hours to carry out polymerization. The polymerization solution is diluted with THF, coagulated and recovered with hydrochloric acid / methanol, repeatedly washed with methanol, dissolved in THF, purified by reprecipitation into methanol, and the collected polymer is vacuum-dried to obtain 51.0 g of the desired copolymer. (90%) was obtained. The number average molecular weight in terms of polystyrene determined by GPC (THF) was 38,900, and the weight average molecular weight was 160,000.
(Synthesis of polyarylene having a sulfonic acid group)
50 g of the copolymer was placed in a 1000 ml separable flask equipped with a stirrer and a thermometer, 500 ml of sulfuric acid having a concentration of 98% was added, and the mixture was stirred for 24 hours under a nitrogen stream while maintaining the internal temperature at 25 ° C. The obtained solution was poured into a large amount of ion exchange water to precipitate a polymer. The washing of the polymer was repeated until the washing water had a pH of 5. By drying, 56 g (95%) of a sulfonic acid group-containing polymer was obtained. The number average molecular weight in terms of polystyrene determined by GPC (NMP) of the sulfonic acid group-containing polymer was 45,500, and the weight average molecular weight was 176,000. The sulfonic acid equivalent of this sulfonic acid group-containing polymer was 2.1 meq / g.

Example 1
10 g of the polymer obtained in Synthesis Example 2 and 0.1 g of 2,4-dihydroxybenzophenone were dissolved in 100 mL of N-methylpyrrolidone. A film was prepared from this solution by a casting method.

Example 2
A film was prepared in the same manner as in Example 1 except that 0.1 g of 2- (2′-hydroxy-5′-methylphenyl) benzotriazole was used instead of 0.1 g of 2,4-dihydroxybenzophenone.

Example 3
A film was prepared in the same manner as in Example 1 using 10 g of the polymer obtained in Synthesis Example 3 instead of 10 g of the polymer obtained in Synthesis Example 2.

Comparative Example 1
10 g of the polymer obtained in Synthesis Example 2 was dissolved in 100 mL of N-methylpyrrolidone. A film was prepared from this solution by a casting method.

Comparative Example 2
10 g of the polymer obtained in Synthesis Example 3 was dissolved in 100 mL of N-methylpyrrolidone. A film was prepared from this solution by a casting method.
Each film was irradiated with ultraviolet rays (UVA351) for 24 hours. The molecular weight and mechanical properties before and after irradiation were measured, and the results were summarized in a table. In the case of the comparative example not containing the ultraviolet absorber, the molecular weight is significantly reduced due to molecular cutting and the tensile strength resulting therefrom is significantly reduced. It can be seen that is suppressed very well.

Claims (6)

A polymer electrolyte composition comprising (a) a polymer electrolyte and (b) an ultraviolet absorber. The polymer electrolyte composition according to claim 1, wherein the polymer electrolyte is an aromatic polymer having a sulfonic acid group. 3. The polymer electrolyte membrane according to claim 2, wherein the aromatic polymer having a sulfonic acid group is a polyarylene having a sulfonic group. 4. The polymer electrolyte membrane according to claim 3, wherein the polyarylene having a sulfonic acid group comprises a repeating unit represented by the following general formula (A) and a repeating unit represented by the following general formula (B). .

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

(In Formula (B), R ^{1 to} R ⁸ may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a fluorine-substituted alkyl group, an allyl group, an aryl group, and a cyano group. And at least one kind of atom or group, W represents a divalent electron-withdrawing group or single bond, T represents a single bond or a divalent organic group, and p represents 0 or a positive integer.) 2. The polymer electrolyte according to claim 1, wherein the ultraviolet absorber is at least one selected from a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel ultraviolet absorber. Composition. A proton conducting membrane comprising the polymer electrolyte composition according to claim 1.