JP3931975B2 - Proton conducting membrane and fuel cell - Google Patents

Description

［式中、ＲｆはＣ_pＦ_2p+1（ｐ＝１〜２０）で表されるポリフルオロアルキル基を示し、Ｘは−ＣＨ₂−、−ＣＨ₂Ｏ−、−ＮＲ³−、−ＣＯ₂−、−ＣＯＮＲ⁵−、−Ｓ−、−ＳＯ₃−又は−ＳＯ₂ＮＲ³−の１種又は２種以上の結合基（Ｒ⁵は水素原子又は炭素数１〜８のアルキル基）を示し、Ｒ³、Ｒ⁴は上記に同じ。ａは０〜３の整数、ｂは１〜３の整数、ｃは０又は１である。］
で表されるフッ化アルキル基含有アルコキシシラン又はその部分加水分解物（Ｃ）との反応物を主剤とする水溶性処理剤で処理してなり、
上記プロトン伝導性ポリマーが、スルホン酸基及びカルボキシル基の少なくとも一方とフッ素樹脂骨格とを含むポリマーであって、このスルホン酸基及び／又はカルボキシル基と上記加水分解性シラン（Ａ）とを相互反応させて塩を形成したことを特徴とする燃料電池の電解質用プロトン伝導性膜。
［ＩＩ］燃料電池の電解質用プロトン伝導性ポリマーを、（Ｄ）下記一般式（４）
（Ｒ⁶）_d（Ｒ²）_eＳｉＯ_(4-d-e)/2 （４）
（式中、Ｒ⁶は炭素数１〜６のアルキル基、Ｒ²は炭素数１〜４のアルコキシ基又はアシロキシ基であり、ｄは０．７５〜１．５、ｅは０．２〜３で、かつ０．９＜ｄ＋ｅ≦４を満足する正数である。）
で表される有機ケイ素化合物１００重量部と、下記一般式（１）
ＹＲ¹ _mＳｉＲ² _3-m （１）
（式中、Ｒ¹は炭素数１〜８の置換又は非置換の一価炭化水素基、Ｒ²は上記と同じ、Ｙは窒素原子含有有機基であり、ｍは０又は１である。）
で表される窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物０．５〜４９重量部とを有機酸又は無機酸の存在下で共加水分解縮合させたもので処理してなり、
上記プロトン伝導性ポリマーが、スルホン酸基及びカルボキシル基の少なくとも一方とフッ素樹脂骨格とを含むポリマーであって、このスルホン酸基及び／又はカルボキシル基と上記加水分解性シラン（Ａ）とを相互反応させて塩を形成したことを特徴とする燃料電池の電解質用プロトン伝導性膜。
【００１３】
本発明のプロトン伝導性膜において、前記プロトン伝導性ポリマーは、スルホン酸基及びカルボキシル基の少なくとも一方とフッ素樹脂骨格とを含むポリマーであることが好ましい。また、本発明のプロトン伝導性膜は、酸でドープされていることが好ましい。
【００１４】
更に、本発明によれば、電解質膜と、この電解質膜を挟持する燃料極及び酸化剤極とを具備する燃料電池において、前記電解質膜は上述したプロトン伝導性膜を含むことを特徴とする燃料電池を提供する。
【００１５】
以下、本発明を詳細に説明する。
本発明のプロトン伝導性膜において、プロトン伝導性ポリマーとしては、例えば、フッ素樹脂骨格とスルホン酸基とを含有するフッ素ポリマー、及びフッ素樹脂骨格とカルボキシル基とを含有するフッ素ポリマーなどを用いることができる。特に、耐久性、膜強度、及びイオン導電性の点から、スルホン酸基及びカルボキシル基の少なくとも一方とフッ素樹脂骨格とを含むポリマーが最適である。
【００１６】
まず、第１発明について説明する。
第１発明に係るプロトン伝導性膜は、上記プロトン伝導性ポリマーの膜を、下記一般式（１）
ＹＲ¹ _mＳｉＲ² _3-m （１）
（式中、Ｒ¹は炭素数１〜８の置換又は非置換の一価炭化水素基、Ｒ²は炭素数１〜４のアルコキシ基又はアシロキシ基、Ｙは窒素原子含有有機基であり、ｍは０又は１である。）
で表される窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物１００重量部と、下記一般式（２）
Ｒ³ _nＳｉＲ⁴ _4-n （２）
（式中、Ｒ³は炭素数１〜８の置換又は非置換の一価炭化水素基、Ｒ⁴は炭素数１〜４のアルコキシ基又はアシロキシ基、ｎは０、１又は２である。）
で表される加水分解性シラン（Ｂ）又はその部分加水分解物５〜２００重量部とを加水分解することによって得られる有機ケイ素化合物で処理したものである。
【００１７】
ここで、上記窒素原子含有有機基を含有する加水分解性シラン（Ａ）は、系を水溶性及び前述のプロトン伝導性ポリマーのスルホン酸基やカルボキシル基等と相互反応することにより塩を形成させるために用いられる成分で、下記一般式（１）で表されるものであり、その１種又は２種以上を適宜選定して用いられる。また、その部分加水分解物を用いることもできる。
ＹＲ¹ _mＳｉＲ² _3-m （１）
【００１８】
式中、Ｒ¹は炭素数１〜８の窒素原子を含まない置換又は非置換の一価炭化水素基であり、アルキル基、アルケニル基、アリール基、アラルキル基などや、これらの基の水素原子の一部又は全部をハロゲン原子などで置換した例えばハロゲン化アルキル基などが挙げられる。具体的には、−ＣＨ₃、−ＣＨ₂ＣＨ₃、−ＣＨ₂ＣＨ₂ＣＨ₃、−ＣＨ（ＣＨ₃）₂、−ＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃、−ＣＨ（ＣＨ₃）ＣＨ₂ＣＨ₃、−ＣＨ₂ＣＨ（ＣＨ₃）ＣＨ₃、−Ｃ（ＣＨ₃）₃、−Ｃ₆Ｈ₅、−Ｃ₆Ｈ₁₃などが例示される。
【００１９】
また、Ｒ²は炭素数１〜４のアルコキシ基又はアシロキシ基であり、具体的には、−ＯＣＨ₃、−ＯＣＨ₂ＣＨ₃、−ＯＣＨ₂ＣＨ₂ＣＨ₃、−ＯＣＨ（ＣＨ₃）₂、−ＯＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃、−ＯＣＨ（ＣＨ₃）ＣＨ₂ＣＨ₃、−ＯＣＨ₂ＣＨ（ＣＨ₃）ＣＨ₃、−ＯＣ（ＣＨ₃）₃、−ＯＣＯＣＨ₃、−ＯＣＯＣＨ₂ＣＨ₃などが例示されるが、中でも−ＯＣＨ₃、−ＯＣＨ₂ＣＨ₃が好ましい。
【００２０】
Ｙは窒素原子含有有機基であり、例えば下記式（５）〜（９）で示されるものが挙げられる。
【化４】

（式中、Ｒ⁷、Ｒ⁸、Ｒ¹¹〜Ｒ¹⁸は水素原子又は炭素数１〜８の一価炭化水素基で、Ｒ⁷とＲ⁸、Ｒ¹¹とＲ¹²とＲ¹³、Ｒ¹⁴とＲ¹⁵、Ｒ¹⁶、Ｒ¹⁷、Ｒ¹⁸は互いに同一であっても異なっていてもよい。Ｒはハロゲン原子を示す。Ｒ⁹、Ｒ¹⁰は炭素数１〜８の二価炭化水素基で、Ｒ⁹とＲ¹⁰は互いに同一であっても異なっていてもよい。ｑは０又は１〜３の整数である。）
【００２１】
なお、炭素数１〜８の一価炭化水素基は、Ｒ¹で説明したものと同様である。炭素数１〜８の二価炭化水素基としては、アルキレン基などが挙げられる。
【００２２】
Ｙとして具体的には、下記式で示されるものを挙げることができる。
Ｈ₂ＮＣＨ₂−、Ｈ（ＣＨ₃）ＮＣＨ₂−、Ｈ₂ＮＣＨ₂ＣＨ₂−、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂−、Ｈ₂ＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＣＨ₂−、（ＣＨ₃）₂ＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、（ＣＨ₃）₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、Ｃｌ^-（ＣＨ₃）₃Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂−、Ｃｌ^-（ＣＨ₃）₂（Ｃ₆Ｈ₅ＣＨ₂）Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂−、
【００２３】
【化５】

【００２４】
これらの中で以下のものが好ましい。
Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂−、
【化６】

【００２５】
なお、式（１）において、ｍは０又は１である。
【００２６】
上記式（１）の窒素原子含有有機基を含有する加水分解性シラン（Ａ）としては、下記のものを例示することができる。
Ｈ₂ＮＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ（ＣＨ₃）ＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、（ＣＨ₃）₂ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、（ＣＨ₃）₂ＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｃｌ^-（ＣＨ₃）₃Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｃｌ^-（ＣＨ₃）₃Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｃｌ^-（ＣＨ₃）₂（Ｃ₆Ｈ₅ＣＨ₂）Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｃｌ^-（ＣＨ₃）₂（Ｃ₆Ｈ₅ＣＨ₂）Ｎ⁺ＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、
【００２７】
【化７】

【００２８】
【化８】

【００２９】
これらの中で、特に好ましくは、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂ＮＣＨ₂ＣＨ₂ＨＮＣＨ₂ＣＨ₂ＣＨ₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃であり、これらの部分加水分解物を用いてもよい。
【００３０】
一方、上記加水分解性シラン（Ａ）又はその部分加水分解物と混合して用いられる加水分解性シラン（Ｂ）は、下記一般式（２）で表され、その１種を単独で又は２種以上を組み合わせて用いることができ、その部分加水分解物を使用してもよい。
Ｒ³ _nＳｉＲ⁴ _4-n （２）
【００３１】
ここで、Ｒ³は炭素数１〜８の窒素原子を含まない置換又は非置換の一価炭化水素基であり、上記Ｒ¹で説明したものと同様である。具体的には、−ＣＨ₃、−ＣＨ₂ＣＨ₃、−ＣＨ₂ＣＨ₂ＣＨ₃、−ＣＨ（ＣＨ₃）₂、−ＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃、−ＣＨ（ＣＨ₃）ＣＨ₂ＣＨ₃、−ＣＨ₂ＣＨ（ＣＨ₃）ＣＨ₃、−Ｃ（ＣＨ₃）₃、−Ｃ₆Ｈ₅、−Ｃ₆Ｈ₁₃などが例示される。
【００３２】
また、Ｒ⁴は炭素数１〜４のアルコキシ基又はアシロキシ基であり、具体的には、−ＯＣＨ₃、−ＯＣＨ₂ＣＨ₃、−ＯＣＨ₂ＣＨ₂ＣＨ₃、−ＯＣＨ（ＣＨ₃）₂、−ＯＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃、−ＯＣＨ（ＣＨ₃）ＣＨ₂ＣＨ₃、−ＯＣＨ₂ＣＨ（ＣＨ₃）ＣＨ₃、−ＯＣ（ＣＨ₃）₃、−ＯＣＯＣＨ₃、−ＯＣＯＣＨ₂ＣＨ₃などが例示されるが、中でも−ＯＣＨ₃、−ＯＣＨ₂ＣＨ₃が好ましい。
【００３３】
なお、式（２）において、ｎは０、１又は２である。
【００３４】
この式（２）の加水分解性シラン（Ｂ）としては、下記のものを例示することができる。Ｓｉ（ＯＣＨ₃）₄、Ｓｉ（ＯＣＨ₂ＣＨ₃）₄、Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₃）₄、Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃）₄、ＣＨ₃Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、ＣＨ₃Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₃）₃、ＣＨ₃Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃）₃、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₃）₂、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₂、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₃）₂、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₂ＣＨ₂ＣＨ₂ＣＨ₃）₂、
【化９】

【００３５】
これらの中で、特に好ましくは、Ｓｉ（ＯＣＨ₃）₄、Ｓｉ（ＯＣＨ₂ＣＨ₃）₄、ＣＨ₃Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃及びこれらの部分加水分解物である。
【００３６】
上記窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物に式（２）の加水分解性シラン（Ｂ）又はその部分加水分解物を混合して用いる場合、その混合比は、窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物１００重量部に対し加水分解性シラン（Ｂ）又はその部分加水分解物５〜２００重量部の割合であり、より好ましくは加水分解性シラン（Ｂ）又はその部分加水分解物の量が１０〜１５０重量部である。この量が２００重量部を超えると液の安定性が悪化する。
【００３７】
上記加水分解性シラン（Ａ）、（Ｂ）又はそれらの部分加水分解物を用いて加水分解し、本発明の有機ケイ素化合物を得る場合、溶媒は主として水を使用するが、必要に応じて、水と溶解する有機溶媒であるアルコール、エステル、ケトン、グリコール類を水に添加する形で用いることができる。有機溶媒としては、メチルアルコール、エチルアルコール、１−プロピルアルコール、２−プロピルアルコール等のアルコール類、酢酸メチル、酢酸エチル、アセト酢酸エチル等のエステル類、アセトン、メチルエチルケトン等のケトン類、グリセリン、ジエチレングリコール等のグリコール類などを挙げることができる。
【００３８】
溶媒の量は原料シラン１００重量部に対して４００〜５０００重量部が好ましい。更に好ましくは１０００〜３０００重量部である。溶媒の量が少なすぎると反応が進行しすぎ、系が均一にならない場合がある。また液の保存安定性も悪くなる場合がある。一方、多すぎると経済的に不利な場合が生じる。
【００３９】
また、溶媒中の水の量は、水／原料シランのモル比率で５〜５０が好ましい。このモル比率が５より少ないと加水分解が完全に進行しにくく、液の安定性が悪化する場合がある。一方、５０を超えると経済的に不利な場合が生じる。
【００４０】
反応方法としては、（１）混合シランを水中あるいは加水分解に必要である以上の量の水を含む有機溶剤中に滴下する方法、（２）混合シランあるいは有機溶剤含有混合シラン中に水を滴下する方法、（３）加水分解性シラン（Ｂ）又はその部分加水分解物を水中あるいは加水分解に必要である以上の量の水を含む有機溶剤中に滴下し、その後、窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物を滴下する方法、（４）窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物を水中あるいは加水分解に必要である以上の量の水を含む有機溶剤中に滴下し、その後、加水分解性シラン（Ｂ）又はその部分加水分解物を滴下する方法などが挙げられるが、有機ケイ素化合物の安定性の点から、特に（１）の反応方法が好ましい。
【００４１】
なお、得られた有機ケイ素化合物は水溶液の形で得られるが、必要に応じて、更に水を加えたり、除去したりして、有機ケイ素化合物１００重量部に対して水１０〜２０００重量部、好ましくは１０〜１０００重量部の比率に調整することにより、有機ケイ素化合物水溶液を形成することが好ましい。この場合、水の量が少なすぎると有機ケイ素化合物自体の保存安定性が悪化する場合がある。また、多すぎると有機ケイ素化合物を加える量が多くなってしまい、コスト的に好ましくない。
【００４２】
このようにして得られた有機ケイ素化合物は水溶液タイプであるため、プロトン伝導性ポリマーを処理する際も、ポリマーとのなじみもよく、スムーズに処理ができ、ポリマーを均一に改質できる。また、アミノアルコキシシランモノマーのメタノール溶液処理のように、一旦処理してから、更に沸騰水中に新たに浸漬して加水分解を促さなくてもよいという利点もある。更に処理濃度も１０重量％以上にできるため、処理効率も改善することができる。また、この有機ケイ素化合物水溶液の保存安定性も高く、液を無駄にすることがなく、コスト的にも有利となる。
【００４３】
プロトン伝導性ポリマー処理時の有機ケイ素化合物濃度は１０〜４０重量％、特に好ましくは１５〜３０重量％が好ましい。濃度が薄すぎると処理効率が悪くなる場合が生じる。濃すぎると、水溶液の安定性が悪くなる場合が生じる。
【００４４】
プロトン伝導性ポリマーを処理する場合は、この有機ケイ素化合物水溶液中にプロトン伝導性ポリマーを浸漬し処理するのが好ましい。浸漬時間は好ましくは１分〜２時間、より好ましくは１分〜２０分である。
【００４５】
この場合、処理液が水溶液のため、短時間処理でも十分である。この時の処理温度は好ましくは２０〜８０℃、より好ましくは３０〜６０℃である。
【００４６】
処理後、乾燥させて目的のプロトン伝導性膜を得ることができるが、この時、室温下あるいは３０〜８０℃の加温下で乾燥させることにより、目的のプロトン伝導性膜を好適に製造することができる。
【００４７】
次に第２発明について説明する。第２発明はフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランと窒素原子含有有機基を含有する加水分解性シランを共加水分解・縮合した水溶性反応物でプロトン伝導性ポリマーを処理するものである。この場合、この反応物はフッ化アルキル基含有シラン化合物自体に水溶性が付与されたものであり、水に容易に溶解するため、フッ化アルキル基由来の優れた撥水性を付与することができることにより、メタノールのクロスオーバーを防ぐことができる。
【００４８】
以下、第２発明について更に説明すると、用いるフッ化アルキル基含有アルコキシシランは下記一般式（３）で示されるものであり、その部分加水分解物でもよい。
【００４９】
【化１０】

［式中、ＲｆはＣ_pＦ_2p+1（ｐ＝１〜２０）で表されるポリフルオロアルキル基を示し、Ｘは−ＣＨ₂−、−ＣＨ₂Ｏ−、−ＮＲ³−、−ＣＯ₂−、−ＣＯＮＲ⁵−、−Ｓ−、−ＳＯ₃−又は−ＳＯ₂ＮＲ³−の１種又は２種以上の結合基（Ｒ⁵は水素原子又は炭素数１〜８のアルキル基）を示し、Ｒ³、Ｒ⁴は上記に同じ。ａは０〜３の整数、ｂは１〜３の整数、ｃは０又は１である。］
【００５０】
このような一般式（３）のシランとしては、下記のものを例示することができる。
下記式において、ＲｆはＣ_pＦ_2p+1（ｐは１〜２０の整数）であり、ＣＦ₃−、Ｃ₂Ｆ₅−、Ｃ₃Ｆ₇−、Ｃ₄Ｆ₉−、Ｃ₆Ｆ₁₃−、Ｃ₈Ｆ₁₇−、Ｃ₁₀Ｆ₂₁−、Ｃ₁₂Ｆ₂₅−、Ｃ₁₄Ｆ₂₉−、Ｃ₁₆Ｆ₃₃−、Ｃ₁₈Ｆ₃₇−、Ｃ₂₀Ｆ₄₁−などが例示される。
Ｒｆ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
Ｒｆ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｒｆ（ＣＨ₂）₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
Ｒｆ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｒｆ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｒｆ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂、
Ｒｆ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
Ｒｆ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｒｆ（ＣＨ₂）₃Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
Ｒｆ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｒｆ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｒｆ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂、
ＲｆＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
ＲｆＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＲｆＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
ＲｆＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
ＲｆＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
ＲｆＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
ＲｆＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂、
ＲｆＣＯＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
ＲｆＣＯＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＲｆＣＯＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
ＲｆＣＯＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
ＲｆＣＯＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
ＲｆＣＯＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
ＲｆＳＯ₂ＮＨ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ（ＣＨ₃）₂）₂
などが挙げられるが、好ましいものとして下記のものが挙げられる。
Ｃ₈Ｆ₁₇（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
Ｃ₈Ｆ₁₇（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₈Ｆ₁₇（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₈Ｆ₁₇（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₃、
Ｃ₄Ｆ₉（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
Ｃ₄Ｆ₉（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₄Ｆ₉（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₄Ｆ₉（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｃ₈Ｆ₁₇ＣＯＮＨ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃
特にＣ₈Ｆ₁₇（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃が好ましい。
【００５１】
本発明において、フッ化アルキル基含有アルコキシシランとしては、上記シランの他に、上記シランの部分加水分解物を用いることができる。但し、この場合、少なくとも１個は加水分解性基が残存している必要がある。所望により、各種シラン混合物を使用してもよいし、混合シランの部分加水分解物であってもよい。
【００５２】
第２発明は、上記式（３）のフッ化アルキル基含有アルコキシシランに、第１発明で説明した一般式（２）の加水分解性シラン（Ｂ）又はその部分加水分解物、及び一般式（１）の窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物を反応させた反応物を使用する。
【００５３】
この場合、式（２）の加水分解性シラン（Ｂ）は、先に述べた通りのものが使用されるが、特に下記のものが好適に用いられる。
Ｃ₁₀Ｈ₂₁Ｓｉ（ＯＣＨ₃）₃、
Ｃ₁₀Ｈ₂₁Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₁₀Ｈ₂₁ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₁₀Ｈ₂₁ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｃ₆Ｈ₁₃Ｓｉ（ＯＣＨ₃）₃、
Ｃ₆Ｈ₁₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₆Ｈ₁₃ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₆Ｈ₁₃ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｃ₃Ｈ₇Ｓｉ（ＯＣＨ₃）₃、
Ｃ₃Ｈ₇Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₃Ｈ₇ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₃Ｈ₇ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｃ₂Ｈ₅Ｓｉ（ＯＣＨ₃）₃、
Ｃ₂Ｈ₅Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₂Ｈ₅ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｃ₂Ｈ₅ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
ＣＨ₃Ｓｉ（ＯＣＨ₃）₃、
ＣＨ₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
（ＣＨ₃）₂Ｓｉ（ＯＣＨ₃）₂、
（ＣＨ₃）₂Ｓｉ（ＯＣ₂Ｈ₅）₂
これらの中で、特に
Ｃ₁₀Ｈ₂₁Ｓｉ（ＯＣＨ₃）₃、
Ｃ₁₀Ｈ₂₁ＳｉＣＨ₃（ＯＣＨ₃）₂、
（ＣＨ₃）₂Ｓｉ（ＯＣＨ₃）₂、
（ＣＨ₃）₂Ｓｉ（ＯＣ₂Ｈ₅）₂
などが好適に用いられる。
【００５４】
本発明において、アルキル基含有アルコキシシランとしては、上記シランの他に上記シランの部分加水分解物も使用し得る。
【００５５】
更に、窒素原子含有有機基を含有する加水分解性シラン（Ａ）も先に述べたものが使用されるが、下記のものが好ましい。
Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｈ₂Ｎ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
Ｈ₂Ｎ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₅Ｓｉ（ＯＣＨ₃）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₅Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｈ₂Ｎ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｈ₂Ｎ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣ₂Ｈ₅）₂
これらの中で、特に
Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、
Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣ₂Ｈ₅）₃、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、
Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂
などが好適に用いられる。また、これらの部分加水分解物を使用することもできる。
【００５６】
ここで、これらフッ化アルキル基含有アルコキシシランと窒素原子含有有機基を含有する加水分解性シランとアルキル基含有アルコキシシランの反応物は、これら３成分を有機酸あるいは無機酸の存在下に共加水分解・縮合させることにより得ることができる。安定性の点により、最初にフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとを有機酸あるいは無機酸の存在下、部分加水分解し、次いでフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとの部分加水分解物と窒素原子含有有機基を含有する加水分解性シランとを反応させることによって得ることが好ましい。
【００５７】
フッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとを加水分解する際に使用される有機酸及び無機酸としては、塩酸、硫酸、メタンスルホン酸、ギ酸、酢酸、プロピオン酸、クエン酸、シュウ酸及びマレイン酸などから選ばれる少なくとも１種の酸が用いられるが、処理した際の基材への腐食性の観点からなるべく弱酸が好ましく、特に酢酸、プロピオン酸が好適である。この酸の使用量はフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとの総量１００重量部に対して好ましくは３０〜４００重量部、より好ましくは４０〜３５０重量部である。この酸の使用量が少なすぎると加水分解の進行が遅く、また、組成物の水溶液の安定性が悪化することがある。
【００５８】
加水分解の際は溶剤で希釈した状態で行うことが好ましい。溶剤としては、アルコール系溶剤が好適であり、メタノール、エタノール、１−プロパノール、２−プロパノール、１−ブタノール、２−ブタノール、３−ブタノール及び２−メチル−２−ブタノールが好適である。特に好ましくは３−ブタノールである。この溶剤の使用量はフッ化アルキル基含有アルコキシシラン量あるいはフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとの総量１００重量部に対して好ましくは１００〜５００重量部、より好ましくは２００〜４００重量部である。この溶剤の使用量が少なすぎると、縮合が進んでしまうことがあり、また多すぎると、加水分解に時間がかかることがある。
【００５９】
フッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとを加水分解させるために加える水量は、フッ化アルキル基含有アルコキシシランのモル量あるいはフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランの総モル量に対し好ましくは１〜３倍モル量、より好ましくは１．２〜２．５倍モル量である。加える水量が１倍モル量より少ないとアルコキシ基が多く残存する場合がある。また、３倍モル量を超えると縮合が進行しすぎる場合がある。
【００６０】
上記フッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとを加水分解させる際の反応条件は、反応温度が好ましくは１０〜１００℃、より好ましくは６０〜９０℃がよく、反応時間は１〜３時間で加水分解反応させることがよい。
【００６１】
なお、フッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとを反応させる場合の比率は１：０．０５〜１：０．５のモル比となるのが好ましい。アルキル基含有アルコキシシランのモル比が０．０５より小さいと耐久性が悪化する場合がある。また０．５より大きいと水溶性が悪化する場合がある。
【００６２】
このようにして得られたフッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランとの反応生成物を、次のように窒素原子含有有機基を含有する加水分解性シランと連続的に反応させる。この場合、フッ化アルキル基含有アルコキシシランとアルキル基含有アルコキシシランの合計量と窒素原子含有有機基を含有する加水分解性シランとのモル比は１：０．５〜１：２０になるように窒素原子含有有機基を含有する加水分解性シランを反応させることが好ましい。窒素原子含有有機基を含有する加水分解性シランのモル比が０．５より小さいと水溶性が悪化することがある。また２０を超えると撥水性能が悪くなることがある。
【００６３】
この窒素原子含有有機基を含有する加水分解性シランを反応させる際の反応条件は、反応温度６０〜１００℃、特に反応時間１〜３時間が好ましい。
【００６４】
このようにして得られた反応物は水溶性であって、水溶液タイプであるため、プロトン伝導性ポリマーを処理する際も、ポリマーとのなじみもよく、スムーズに処理を行うことができるため、均一に改質できる。更にこの場合は処理濃度が薄くても十分に処理できるため、処理効率も改善することができる。また、この処理剤水溶液の保存安定性も高く、液を無駄にすることがなく、コスト的にも有利となる。
【００６５】
このようにして得られた水溶性反応物を有効成分として好ましくは０．１〜１０重量％、より好ましくは０．５〜２重量％を水に均一混合した処理剤でプロトン伝導性ポリマーを処理する。この時、反応物の濃度が薄すぎると処理効率が悪くなるおそれがある。また、多すぎると、水溶液の安定性が悪くなることがある。
【００６６】
プロトン伝導性ポリマーを処理する場合は、この処理剤水溶液中にプロトン伝導性ポリマーを浸漬し、処理するのが好ましい。浸漬時間は好ましくは１分〜２時間、より好ましくは１〜２０分である。この場合、処理液が水溶液のため短時間処理でも十分である。この時の処理温度は好ましくは２０〜８０℃、より好ましくは３０〜６０℃である。
【００６７】
処理後、乾燥させて目的のプロトン伝導性膜を得ることができるが、この時、室温下あるいは３０〜８０℃の加温下で乾燥させることにより目的のプロトン伝導性膜を製造することが好ましい。
【００６８】
更に第３発明について説明する。第３発明は下記一般式（４）で示される有機ケイ素化合物（Ｄ）と上記窒素原子含有有機基を含有する加水分解性シラン（Ａ）又はその部分加水分解物とを共加水分解縮合させたものでプロトン伝導性ポリマーを処理するものである。この場合、この反応物（共加水分解縮合物）はアルキルシロキサン化合物自体に水溶性が付与されたものであり、水に容易に溶解するため、アルキルシロキサン由来の優れた撥水性を付与することができることにより、メタノールのクロスオーバーを防ぐことができる。
【００６９】
以下、第３発明について更に詳しく説明すると、用いる有機ケイ素化合物（Ｄ）は下記一般式（４）で示されるものである。
（Ｒ⁶）_d（Ｒ²）_eＳｉＯ_(4-d-e)/2 （４）
（式中、Ｒ⁶は炭素数１〜６のアルキル基、Ｒ²は炭素数１〜４のアルコキシ基又はアシロキシ基であり、ｄは０．７５〜１．５、ｅは０．２〜３で、かつ０．９＜ｄ＋ｅ≦４を満足する正数である。）
【００７０】
上記式（４）のＲ⁶は炭素数１〜６、好ましくは１〜３のアルキル基である。具体的にはメチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｎ−ペンチル基、ｎ−ヘキシル基等が挙げられ、特にメチル基が好ましい。
【００７１】
Ｒ²は第１発明のものと同じであり、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基等が挙げられ、メチル基、エチル基が好ましい。
【００７２】
このような式（４）の有機ケイ素化合物の具体例としては、下記化合物を挙げることができる。
ＣＨ₃Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃Ｓｉ（ＯＣ₂Ｈ₅）₃、ＣＨ₃Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、ＣＨ₃ＣＨ₂Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃ＣＨ₂Ｓｉ（ＯＣ₂Ｈ₅）₃、ＣＨ₃ＣＨ₂Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、Ｃ₃Ｈ₇Ｓｉ（ＯＣＨ₃）₃、Ｃ₃Ｈ₇Ｓｉ（ＯＣ₂Ｈ₅）₃、Ｃ₃Ｈ₇Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、Ｃ₄Ｈ₉Ｓｉ（ＯＣＨ₃）₃、Ｃ₄Ｈ₉Ｓｉ（ＯＣ₂Ｈ₅）₃、Ｃ₄Ｈ₉Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、Ｃ₅Ｈ₁₁Ｓｉ（ＯＣＨ₃）₃、Ｃ₅Ｈ₁₁Ｓｉ（ＯＣ₂Ｈ₅）₃、Ｃ₅Ｈ₁₁Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃、Ｃ₆Ｈ₁₃Ｓｉ（ＯＣＨ₃）₃、Ｃ₆Ｈ₁₃Ｓｉ（ＯＣ₂Ｈ₅）₃、Ｃ₆Ｈ₁₃Ｓｉ（ＯＣＨ（ＣＨ₃）₂）₃
【００７３】
本発明においては、上記各種シランを単独で使用しても２種類以上の混合物を使用してもよいし、混合シランの部分加水分解物を使用してもよい。
【００７４】
また、（Ｄ）成分として当該技術分野において周知であるように、上記シランを部分加水分解縮合したアルコキシ基含有シロキサンを用いることができる（この場合の部分加水分解物のケイ素原子の数は２〜１０、特に２〜４であることが好ましい）。更に、（Ｄ）成分としては、水中で炭素原子数１〜６のアルキルトリクロロシランとメタノール又はエタノールとを反応させることにより得られるものでもよい（この場合もケイ素原子数が２〜６、特に２〜４であることが好ましく、また、２５℃で３００ｍｍ²／ｓ以下の粘度を有しているものが好ましく、特に１〜１００ｍｍ²／ｓの粘度を有するものが好適である）。
【００７５】
本発明の窒素原子含有有機基を含有する加水分解性シラン（Ａ）は第１発明の上記一般式（１）で示されるものであり、先に説明したものを使用し得るが、特に下記のものが好ましい。
Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₂Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₅Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₅Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃、Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃、Ｈ₂Ｎ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂Ｎ（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ₂Ｎ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂Ｎ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₅ＳｉＣＨ₃（ＯＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₅ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｈ₂Ｎ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、ＣＨ₃ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂、Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₃）₂、Ｃ₄Ｈ₉ＮＨ（ＣＨ₂）₂ＮＨ（ＣＨ₂）₃ＳｉＣＨ₃（ＯＣＨ₂ＣＨ₃）₂
【００７６】
これらの中で、特にＮ−（２−アミノエチル）−３−アミノプロピルトリメトキシシラシ、Ｎ−（２−アミノエチル）−３−アミノプロピルメチルジメトキシシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルトリエトキシシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルメチルジエトキシシラン、３−アミノプロピルトリメトキシシラン、３−アミノプロピルメチルジメトキシシラン、３−アミノプロピルトリエトキシシラン、３−アミノプロピルメチルジエトキシシランなどが好適に用いられる。
なお、これらの部分加水分解物であってもよい。
【００７７】
上記（Ｄ）及び（Ａ）成分の使用割合は、（Ｄ）成分１００重量部に対して（Ａ）成分０．５〜４９重量部、好ましくは５〜２０重量部である。（Ａ）成分が０．５重量部未満であると水溶性が弱くなり、水溶液にした時の安定性が悪くなる。また、（Ａ）成分が４９重量部を超えると撥水性、長期吸水防止性が悪くなったり、中性基材に処理したときに黄変が激しくなる。
【００７８】
モル換算としては、（Ｄ）成分のＳｉ原子１モルに対し（Ａ）成分のＳｉ原子が０．０１〜０．３モル、特に０．０５〜０．２モルとなるように用いることが好ましい。
【００７９】
これら（Ｄ）及び（Ａ）成分は、有機酸又は無機酸の存在下で共加水分解させればよい。この場合、最初に（Ｄ）成分を有機酸あるいは無機酸の存在下で加水分解し、この（Ｄ）成分の加水分解物と（Ａ）成分を混合し、有機酸あるいは無機酸の存在下、更に加水分解させることが好ましい。
【００８０】
（Ｄ）成分を加水分解する際に使用される有機酸及び無機酸としては、例えば塩酸、硫酸、メタンスルホン酸、ギ酸、酢酸、プロピオン酸、クエン酸、シュウ酸及びマレイン酸などから選ばれる少なくとも１種の酸が用いられるが、特に好適なものは酢酸、プロピオン酸である。この酸の使用量は、（Ｄ）成分１００重量部に対して２〜４０重量部、特に３〜１５重量部が好適である。
【００８１】
加水分解の際は適度に溶剤で希釈した状態で行うのが好ましい。溶剤としては、アルコール系溶剤が好適であり、特にメタノール、エタノール、イソプロピルアルコール、第三ブチルアルコールが好適である。この溶剤の使用量は、（Ｄ）成分１００重量部に対して５０〜３００重量部、特に７０〜２００重量部が好ましい。溶剤の使用量が少なすぎると、縮合が進んでしまう場合があり、また多すぎると、加水分解に時間がかかることがある。
【００８２】
また、（Ｄ）成分を加水分解させるために加える水量は、（Ｄ）成分１モルに対し０．５〜４モル量、特に１〜３モル量が好適である。加える水量が少なすぎるとアルコキシ基が多く残存してしまう場合があり、多すぎると縮合が進行しすぎる場合がある。
【００８３】
（Ｄ）成分を加水分解させる際の反応条件は、反応温度１０〜４０℃、特に２０〜３０℃がよく、反応時間は１〜３時間で加水分解反応させるのがよい。
【００８４】
以上で得られた（Ｄ）成分の加水分解物と（Ａ）成分とを反応させる。なお、反応条件は、反応温度６０〜１００℃、反応時間１〜３時間が好ましい。反応終了後は、溶剤の沸点以上まで温度を上げ、アルコール溶剤を留去させる。この場合、系内の全アルコール（反応溶剤としてのアルコール、副生成物としてのアルコール）の含有量を３０重量％以下、特に１０重量％以下となるように留去させることが好ましい。アルコールが多く含まれていると、水で希釈した場合、白濁したりゲル化したりすることがあり、保存安定性も低下することがある。上記方法で製造できる反応生成物は、２５℃における粘度が５〜２０００ｍｍ²／ｓ、特に５０〜５００ｍｍ²／ｓであることが好ましい。粘度が高すぎると作業性や保存安定性が低下したり、水への溶解性が低下することがある。また、重量平均分子量は５００〜５０００、特に８００〜２０００の範囲であることが望ましい。
【００８５】
このようにして得られた反応物は水溶液タイプであるため、プロトン伝導性ポリマーを処理する際も、ポリマーとのなじみもよく、スムーズに処理することができるため、均一に改質できる。更にこの場合は処理濃度が薄くても十分に処理できるため、処理効率も改善することができる。また、この処理剤水溶液の保存安定性も高く、液を無駄にすることがなく、コスト的にも有利となる。
【００８６】
このようにして得られた水溶性反応物を有効成分として０．０１〜２０重量％、より好ましくは１．０〜１０重量％を水に均一混合した処理剤でプロトン伝導性ポリマーを処理することが好ましい。この時、反応物の濃度が薄すぎると処理効率が悪くなるおそれがある。また、濃すぎると、水溶液の安定性が悪くなることがある。
【００８７】
プロトン伝導性ポリマーの処理は、この処理剤水溶液中にプロトン伝導性ポリマーを浸漬し、処理するのが好ましい。浸漬時間は好ましくは１分〜２時間、より好ましくは１〜２０分である。この場合、処理液が水溶液のため、短時間処理でも十分である。この時の処理温度は好ましくは２０〜８０℃、より好ましくは３０〜６０℃である。
【００８８】
処理後、乾燥させて目的のプロトン伝導性膜を得ることができるが、この時、室温下あるいは３０〜８０℃の加温下で乾燥させることにより目的のプロトン伝導性膜を製造することができる。
【００８９】
本発明の電解質用プロトン伝導性膜は、燃料電池のプロトン伝導性膜として、公知のプロトン伝導性膜と同様に、燃料極及び酸化剤極に挟持されて使用される。この場合、この燃料電池の構成は、本発明のプロトン伝導性膜を用いる以外は公知の構成とすることができる。
【００９０】
【実施例】
以下、合成例及び実施例と比較例を示し、本発明を具体的に説明するが、本発明は下記の実施例に制限されるものではない。
【００９７】
処理剤水溶液の合成
［合成例１］
撹拌器、冷却管、温度計及び滴下ロートを備えた０．５Ｌの四つ口フラスコにＣ₈Ｆ₁₇（ＣＨ₂）₂Ｓｉ（ＯＣＨ₃）₃４８．０ｇ（０．０８５ｍｏｌ）、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₃）₂２．０ｇ（０．００９ｍｏｌ）、３−ブタノール１６９ｇ、酢酸１４．２ｇ（０．２３７ｍｏｌ）及び水２．６ｇ（０．１４２ｍｏｌ）を入れて撹拌し、３−ブタノールが還流するまで加熱した。２時間反応させた後、滴下ロートにより、Ｈ₂Ｎ（ＣＨ₂）₂ＨＮ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₃）₃２１．０ｇ（０．０９５ｍｏｌ）を滴下し、更に３−ブタノール還流下で１時間反応させ、淡黄色透明溶液を得た。１０５℃／３時間の条件で不揮発分測定を行ったところ、２０．２％であった。これを水で２重量％となるように希釈し、処理剤水溶液−１とした。
【００９８】
［合成例２］
撹拌器、冷却管、温度計及び滴下ロートを備えた１．０Ｌの四つ口フラスコにＣ₄Ｆ₉（ＣＨ₂）₂ＳｉＣＨ₃（ＯＣＨ₃）₂８０．０ｇ（０．２２７ｍｏｌ）、（ＣＨ₃）₂Ｓｉ（ＯＣＨ₃）₂４．０ｇ（０．０３３ｍｏｌ）、ＣＨ₃Ｓｉ（ＯＣＨ₃）₃９．９３ｇ（０．０７３ｍｏｌ）、メタノール６８ｇ、酢酸３０．０ｇ（０．５ｍｏｌ）及び水９ｇ（０．４９９ｍｏｌ）を入れて撹拌し、メタノールが還流するまで加熱した。２時間反応させた後、滴下ロートにより、Ｈ₂Ｎ（ＣＨ₂）₂ＨＮ（ＣＨ₂）₃Ｓｉ（ＯＣＨ₂ＣＨ₃）₃７３．７ｇ（０．３３３ｍｏｌ）を滴下し、更にメタノール還流下で２時間反応させた。更にエステルアダプターを取り付け、内温１１０℃まで上げ、メタノールを除去し、黄色ペースト物を得た。ここに水を投入し、不揮発分が２重量％になるように調整した。得られたものは透明の水溶液であった。これを処理剤水溶液−２とした。
【００９９】
［合成例３］
冷却管、温度計及び滴下漏斗を備えた５００ｍｌの四つ口フラスコにメチルトリメトキシシランのオリゴマー８５ｇ（ダイマー換算で０．３７ｍｏｌ）、メタノール１５４ｇ及び酢酸５．１ｇを入れ、撹拌しているところに水６．８ｇ（０．３７ｍｏｌ）を投入し、２５℃で２時間撹拌した。そこに、Ｎ−（２−アミノエチル）−３−アミノプロピルトリメトキシシラン８．９ｇ（０．０４ｍｏｌ）を滴下した。その後、メタノールの還流温度まで加熱して１時間反応後、エステルアダプターにて、内温が１１０℃になるまでメタノールを留去し、粘度７１ｍｍ²／ｓの薄黄色透明溶液８１ｇを得た（重量平均分子量１１００）。これを水で５重量％となるように希釈し、淡黄色透明の処理剤水溶液−３を得た。
【０１００】
［合成例４］
Ｎ−（２−アミノエチル）−３−アミノプロピルトリメトキシシランを３−アミノプロピルトリエトキシシラン１７．７ｇ（０．０８ｍｏｌ）とした以外は、合成例３と同様に反応を行い、粘度２２０ｍｍ²／ｓの薄黄色透明溶液９０ｇを得た（重量平均分子量１３００）。これを水で５重量％となるように希釈し、透明の処理剤水溶液−４を得た。
【０１０１】
使用プロトン伝導性ポリマー
使用するプロトン伝導性ポリマーからなる膜として、厚さ１９０μｍの市販のナフィオン膜（Ｎａｆｉｏｎ１１７＠フィルム）を用意し、沸騰水中で１時間処理し、１０％の硝酸に数時間浸漬した。更に、純水で十分に洗浄した後、純水中で保存した。これを処理前に取り出して反応に使用した。
【０１０２】
［実施例１］
前述のナフィオン膜を純水から取り出して、膜表面の水分を濾紙で十分に吸い取った後、上記合成例１の処理剤水溶液−１中に室温で１分間浸漬し、次いで室温で乾燥を行うことよって、サンプルＸＩ−１のプロトン伝導性膜を作製した。得られたプロトン伝導性膜について、メタノール透過性及び電気抵抗を測定した。
【０１０３】
まず、直径３０ｍｍの円形セルを２つ用意して、一方のセルには１０％のメタノール水溶液を収容し、他方のセルには純水を収容した。これら２つのセルでプロトン伝導性高分子膜を挿み込んで、室温で一定時間放置した。その後、純水を収容したセル側のメタノール濃度をガスクロマトグラフィーで測定して、メタノールの透過性を測定した。
【０１０４】
サンプルの膜は、一定時間経過後に純水中から取り出し、水を切ってメタノールの透過性を測定した。メタノールの透過性は、ナフィオンを１として相対的な値で表１に示す。
【０１０５】
また、１０ｃｍ²の面積を有する正方形のセルを２つ準備し、その一方の片側に白金電極を取り付けた。こうした２つのセルとの間にプロトン伝導性膜を挿み込んで、インピーダンスアナライザーで１ｋＨｚにおける値を測定して、膜の電気抵抗を得た。得られた結果を表１に示す。
【０１１８】
［実施例２］
実施例１の処理剤水溶液−１を処理剤水溶液−２に変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＸＩＩ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１１９】
［実施例３］
実施例１の処理剤水溶液−１を処理剤水溶液−３に変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＸＩＩＩ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１２０】
［実施例４］
実施例１の処理剤水溶液−１を処理剤水溶液−４に変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＸＩＶ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１２１】
［比較例１］
実施例１の処理剤水溶液−１を３−アミノプロピルトリメトキシシランの１％メタノール溶液に変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＶＩＩＩ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１２２】
［比較例２］
比較例１の３−アミノプロピルトリメトキシシランをＮ−（２−アミノエチル）−３−アミノプロプルトリメトキシシランに変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＩＸ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１２３】
［比較例３］
比較例１の３−アミノプロピルトリメトキシシランを３−アミノプロピルトリメトキシシラン０．５％、テトラエトキシシラン０．５％の合計１％メタノール混合液に変更した以外は、前述のサンプルＸＩ−１と同様にしてサンプルＸ−１を作製した。得られたプロトン伝導性膜は、実施例１と同様にしてメタノール透過性及び電気抵抗を測定した。その結果を表１に示す。
【０１２４】
［比較例４〜６］
更に、単独のＮａｆｉｏｎ１１７、１１３５及び１０３５についても、上述と同様の手法によりメタノール透過性及び電気抵抗を調べた。その結果を表１に示す。
【０１２５】
【表１】

【０１２６】
表１に示されるように、本発明の製造法によるプロトン伝導性膜においては、膜の電気抵抗（インピーダンス）は、単独のナフィオンの場合の数倍程度の範囲で収まっている。このことから、本発明のプロトン伝導性膜は、プロトン伝導性をある程度維持しつつ、メタノールの透過性を大幅に低減できることが明らかとなった。
【０１２７】
【発明の効果】
本発明によれば、プロトン伝導性を維持しつつ、メタノールのクロスオーバーを抑制することを可能にする燃料電池の電解質用プロトン伝導性膜が提供される。また、本発明のプロトン伝導性膜を用いることにより、小型で性能が高く、しかも安定した出力を供給可能な燃料電池を得ることが可能となり、その工業的価値は絶大である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a proton conductive membrane for an electrolyte membrane of a fuel cell and a fuel cell using the same.
[0002]
[Prior art]
Conventional methanol fuel cells are classified into two types, a liquid supply type and a vaporization supply type, depending on the liquid fuel supply method. Among these, the vaporized supply type fuel cell is highly active and has high performance because the electrode reaction is carried out with the gaseous fuel. On the other hand, the system is extremely complicated and difficult to downsize.
[0003]
In the case of one liquid supply type fuel cell, the system is relatively simple compared to the vaporization supply type, but due to the fact that the electrode reaction is carried out with the liquid fuel, the performance is low and the performance is low. There is a problem that it is low. A liquid fuel cell that utilizes capillary force for fuel supply is also a liquid supply type in which fuel is supplied to the fuel electrode in a liquid state, and thus does not require a pump or the like and is suitable for miniaturization, but the electrode reaction is Low activity and low performance.
[0004]
In addition to the problems described above, the biggest problem in fuel cells is that when a proton conductive solid polymer membrane such as perfluorosulfonic acid (trade name: manufactured by Nafion DuPont) is used as an electrolyte, methanol, etc. That is, a crossover occurs in which the liquid organic fuel permeates the electrolyte membrane to the oxidant electrode side. When this phenomenon occurs, the supplied liquid fuel and oxidant react directly, and energy cannot be output as electric power. Therefore, the critical problem that a stable output cannot be obtained arises. Due to such problems, the present situation is that water is added to methanol for use.
[0005]
In order to prevent this crossover from this point of view, Japanese Patent Application Laid-Open No. 2002-110200 discloses that a proton conductive polymer is treated with aminoalkoxysilane alone or a mixture of aminoalkoxysilane and metal alkoxide. . However, since this method can be processed only in a state of being dissolved in alcohol at a concentration of 10% or less, there is little modification of the proton conductive polymer, and crossover could not be completely prevented. In addition, in the treatment with a mixture of aminosilane and metal alkoxide, aminosilane and metal oxide react when the proton conductive membrane is treated, so that there is a problem that a uniform membrane cannot be formed.
[0006]
[Patent Document 1]
JP 2002-110200 A
[0007]
[Problems to be solved by the invention]
In the conventional fuel cell, the proton-conducting solid polymer membrane could not sufficiently suppress the crossover of methanol, so that a stable output could not be supplied.
[0008]
The present invention has been made in view of the above problems, and provides a proton conductive membrane capable of suppressing crossover of methanol while maintaining proton conductivity and a fuel cell using the same. With the goal.
[0009]
Means for Solving the Problem and Embodiment of the Invention
The present inventors have intensively studied to solve the above-mentioned problems, and have found that treating various water-based organosilicon compounds prevents methanol crossover while maintaining proton conductivity.
[0010]
That is, a proton conductive membrane having a basic skeleton of a fluorine-based resin typified by Nafion exhibits excellent ionic conductivity. Since this high ionic conductivity is exerted through a cluster network in a water-containing state, in a fuel cell using methanol, this methanol is mixed into water from the anode, passes through the cluster network, and diffuses to the cathode. There was a problem of lowering the output voltage. For such proton-conducting membranes, a method of suppressing the swelling by introducing a crosslinked structure or the like is common, but there is a problem that the conductivity is greatly lowered when the entire membrane is crosslinked.
[0011]
The present inventors have found that by controlling the cluster network in the proton conductive membrane, methanol permeation can be controlled, and methanol crossover can be suppressed while maintaining proton conductivity. As a method for controlling such a cluster network, by treating the proton conductive membrane with a specific organosilicon compound, the permeation selectivity between water and methanol is improved while maintaining high proton conductivity of the proton conductive membrane. It has been found that the present invention has been made.
[0012]
  Accordingly, the present invention provides the following proton conductive membrane for electrolyte of fuel cell.
[I] FlameA proton conductive polymer for electrolyte of a battery is represented by the following general formula (1)
    YR¹ _mSiR² _3-m                                  (1)
(Wherein R¹Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R²Is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, Y is a nitrogen atom-containing organic group, and m is 0 or 1. )
A hydrolyzable silane (A) or a partially hydrolyzed product thereof containing a nitrogen atom-containing organic group represented by the following general formula (2):
    R^Three _nSiR^Four _4-n                                    (2)
(Wherein R^ThreeIs a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R^FourIs an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, and n is 0, 1 or 2. )
A hydrolyzable silane (B) or a partial hydrolyzate thereof, represented by the following general formula (3)
[Chemical Formula 3]

[Wherein Rf is C_pF_{2p + 1}Represents a polyfluoroalkyl group represented by (p = 1 to 20), and X represents —CH.₂-, -CH₂O-, -NR^Three-, -CO₂-, -CONR^Five-, -S-, -SO_Three-Or-SO₂NR^Three-1 type or 2 types or more of bonding group (R^FiveRepresents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms), and R^Three, R^FourIs the same as above. a is an integer of 0 to 3, b is an integer of 1 to 3, and c is 0 or 1. ]
A fluorinated alkyl group-containing alkoxysilane represented by the formula (1) or a reaction product thereof with a partial hydrolyzate (C).The
The proton conductive polymer is a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton, and the sulfonic acid group and / or the carboxyl group interacts with the hydrolyzable silane (A). Let the salt formA proton conductive membrane for an electrolyte of a fuel cell.
[II] A proton conductive polymer for an electrolyte of a fuel cell is represented by (D) the following general formula (4)
    (R⁶)_d(R²)_eSiO_{(4-de) / 2}                    (4)
(Wherein R⁶Is an alkyl group having 1 to 6 carbon atoms, R²Is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, d is 0.75 to 1.5, e is 0.2 to 3, and 0.9 is a positive number satisfying 0.9 <d + e ≦ 4. )
And 100 parts by weight of an organosilicon compound represented by the following general formula (1)
    YR¹ _mSiR² _3-m                                  (1)
(Wherein R¹Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R²Is the same as above, Y is a nitrogen atom-containing organic group, and m is 0 or 1. )
A hydrolyzable silane (A) containing a nitrogen atom-containing organic group represented by the formula: 0.5 to 49 parts by weight of a hydrolyzable silane (A) or a partially hydrolyzed product thereof in the presence of an organic acid or an inorganic acid. I'll handle itThe
The proton conductive polymer is a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton, and the sulfonic acid group and / or the carboxyl group interacts with the hydrolyzable silane (A). Let the salt formA proton conductive membrane for an electrolyte of a fuel cell.
[0013]
In the proton conductive membrane of the present invention, the proton conductive polymer is preferably a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton. The proton conductive membrane of the present invention is preferably doped with an acid.
[0014]
Furthermore, according to the present invention, in a fuel cell comprising an electrolyte membrane, and a fuel electrode and an oxidizer electrode sandwiching the electrolyte membrane, the electrolyte membrane includes the proton conductive membrane described above. Provide batteries.
[0015]
  Hereinafter, the present invention will be described in detail.
  In the proton conducting membrane of the present invention, examples of the proton conducting polymer include:TheA fluorine polymer containing a fluorine resin skeleton and a sulfonic acid group, a fluorine polymer containing a fluorine resin skeleton and a carboxyl group, and the like can be used. In particular, a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton is optimal from the viewpoint of durability, film strength, and ionic conductivity.
[0016]
First, the first invention will be described.
The proton conducting membrane according to the first aspect of the present invention is the proton conducting polymer membrane represented by the following general formula (1):
YR¹ _mSiR² _3-m                                  (1)
(Wherein R¹Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R²Is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, Y is a nitrogen atom-containing organic group, and m is 0 or 1. )
100 parts by weight of a hydrolyzable silane (A) or a partially hydrolyzed product thereof containing a nitrogen atom-containing organic group represented by the following general formula (2)
R^Three _nSiR^Four _4-n                                    (2)
(Wherein R^ThreeIs a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R^FourIs an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, and n is 0, 1 or 2. )
Is treated with an organosilicon compound obtained by hydrolyzing 5 to 200 parts by weight of a hydrolyzable silane (B) or a partially hydrolyzed product thereof.
[0017]
Here, the hydrolyzable silane (A) containing the nitrogen atom-containing organic group forms a salt by interacting the system with a water-soluble and sulfonic acid group or carboxyl group of the proton conductive polymer. Therefore, it is a component represented by the following general formula (1), and one or more of them are appropriately selected and used. Moreover, the partial hydrolyzate can also be used.
YR¹ _mSiR² _3-m                                  (1)
[0018]
Where R¹Is a substituted or unsubstituted monovalent hydrocarbon group not containing a nitrogen atom having 1 to 8 carbon atoms, such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or some or all of the hydrogen atoms of these groups For example, a halogenated alkyl group substituted with a halogen atom. Specifically, -CH_Three, -CH₂CH_Three, -CH₂CH₂CH_Three, -CH (CH_Three)₂, -CH₂CH₂CH₂CH_Three, -CH (CH_Three) CH₂CH_Three, -CH₂CH (CH_Three) CH_Three, -C (CH_Three)_Three, -C₆H_Five, -C₆H₁₃Etc. are exemplified.
[0019]
R²Is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, specifically, —OCH_Three, -OCH₂CH_Three, -OCH₂CH₂CH_Three, -OCH (CH_Three)₂, -OCH₂CH₂CH₂CH_Three, -OCH (CH_Three) CH₂CH_Three, -OCH₂CH (CH_Three) CH_Three, -OC (CH_Three)_Three, -OCOCH_Three, -OCOCH₂CH_ThreeEtc., among others, -OCH_Three, -OCH₂CH_ThreeIs preferred.
[0020]
Y is a nitrogen atom containing organic group, for example, what is shown by following formula (5)-(9) is mentioned.
[Formula 4]

(Wherein R⁷, R⁸, R¹¹~ R¹⁸Is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms, R⁷And R⁸, R¹¹And R¹²And R¹³, R¹⁴And R¹⁵, R¹⁶, R¹⁷, R¹⁸May be the same as or different from each other. R represents a halogen atom. R⁹, R^TenIs a divalent hydrocarbon group having 1 to 8 carbon atoms, R⁹And R^TenMay be the same as or different from each other. q is 0 or an integer of 1-3. )
[0021]
The monovalent hydrocarbon group having 1 to 8 carbon atoms is R¹This is the same as that described in. Examples of the divalent hydrocarbon group having 1 to 8 carbon atoms include an alkylene group.
[0022]
Specific examples of Y include those represented by the following formula.
H₂NCH₂-, H (CH_Three) NCH₂-, H₂NCH₂CH₂-, H (CH_Three) NCH₂CH₂-, H₂NCH₂CH₂CH₂-, H (CH_Three) NCH₂CH₂CH₂-, (CH_Three)₂NCH₂CH₂CH₂-, H₂NCH₂CH₂HNCH₂CH₂CH₂-, H (CH_Three) NCH₂CH₂HNCH₂CH₂CH₂-, (CH_Three)₂NCH₂CH₂HNCH₂CH₂CH₂-, H₂NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂-, H (CH_Three) NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂-, Cl^-(CH_Three)_ThreeN⁺CH₂CH₂CH₂-, Cl^-(CH_Three)₂(C₆H_FiveCH₂) N⁺CH₂CH₂CH₂−,
[0023]
[Chemical formula 5]

[0024]
Of these, the following are preferred.
H₂NCH₂CH₂HNCH₂CH₂CH₂−,
[Chemical 6]

[0025]
In the formula (1), m is 0 or 1.
[0026]
Examples of the hydrolyzable silane (A) containing the nitrogen atom-containing organic group of the above formula (1) include the following.
H₂NCH₂Si (OCH_Three)_Three, H₂NCH₂Si (OCH₂CH_Three)_Three, H₂NCH₂SiCH_Three(OCH_Three)₂, H₂NCH₂SiCH_Three(OCH₂CH_Three)₂, H₂NCH₂CH₂Si (OCH_Three)_Three, H₂NCH₂CH₂Si (OCH₂CH_Three)_Three, H₂NCH₂CH₂SiCH_Three(OCH_Three)₂, H₂NCH₂CH₂SiCH_Three(OCH₂CH_Three)₂, H₂NCH₂CH₂CH₂Si (OCH_Three)_Three, H₂NCH₂CH₂CH₂Si (OCH₂CH_Three)_Three, H₂NCH₂CH₂CH₂SiCH_Three(OCH_Three)₂, H₂NCH₂CH₂CH₂SiCH_Three(OCH₂CH_Three)₂, H (CH_Three) NCH₂CH₂CH₂Si (OCH_Three)_Three, H (CH_Three) NCH₂CH₂CH₂Si (OCH₂CH_Three)_Three, H (CH_Three) NCH₂CH₂CH₂SiCH_Three(OCH_Three)₂, H (CH_Three) NCH₂CH₂CH₂SiCH_Three(OCH₂CH_Three)₂, (CH_Three)₂NCH₂CH₂CH₂Si (OCH_Three)_Three, (CH_Three)₂NCH₂CH₂CH₂Si (OCH₂CH_Three)_Three, Cl^-(CH_Three)_ThreeN⁺CH₂CH₂CH₂Si (OCH_Three)_Three, Cl^-(CH_Three)_ThreeN⁺CH₂CH₂CH₂Si (OCH₂CH_Three)_Three, Cl^-(CH_Three)₂(C₆H_FiveCH₂) N⁺CH₂CH₂CH₂Si (OCH_Three)_Three, Cl^-(CH_Three)₂(C₆H_FiveCH₂) N⁺CH₂CH₂CH₂Si (OCH₂CH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂CH₂Si (OCH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂CH₂Si (OCH₂CH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂CH₂SiCH_Three(OCH_Three)₂, H₂NCH₂CH₂HNCH₂CH₂CH₂SiCH_Three(OCH₂CH_Three)₂, H₂NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂Si (OCH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂Si (OCH₂CH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂SiCH_Three(OCH_Three)₂, H₂NCH₂CH₂HNCH₂CH₂HNCH₂CH₂CH₂SiCH_Three(OCH₂CH_Three)₂,
[0027]
[Chemical 7]

[0028]
[Chemical 8]

[0029]
Of these, H is particularly preferable.₂NCH₂CH₂HNCH₂CH₂CH₂Si (OCH_Three)_Three, H₂NCH₂CH₂HNCH₂CH₂CH₂Si (OCH₂CH_Three)_ThreeThese partial hydrolysates may be used.
[0030]
On the other hand, the hydrolyzable silane (B) used by mixing with the hydrolyzable silane (A) or a partial hydrolyzate thereof is represented by the following general formula (2), one of which is used alone or two of them. The above can be used in combination, and a partial hydrolyzate thereof may be used.
R^Three _nSiR^Four _4-n                                    (2)
[0031]
Where R^ThreeIs a substituted or unsubstituted monovalent hydrocarbon group not containing a nitrogen atom having 1 to 8 carbon atoms, and the above R¹This is the same as that described in. Specifically, -CH_Three, -CH₂CH_Three, -CH₂CH₂CH_Three, -CH (CH_Three)₂, -CH₂CH₂CH₂CH_Three, -CH (CH_Three) CH₂CH_Three, -CH₂CH (CH_Three) CH_Three, -C (CH_Three)_Three, -C₆H_Five, -C₆H₁₃Etc. are exemplified.
[0032]
R^FourIs an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, specifically, —OCH_Three, -OCH₂CH_Three, -OCH₂CH₂CH_Three, -OCH (CH_Three)₂, -OCH₂CH₂CH₂CH_Three, -OCH (CH_Three) CH₂CH_Three, -OCH₂CH (CH_Three) CH_Three, -OC (CH_Three)_Three, -OCOCH_Three, -OCOCH₂CH_ThreeEtc., among others, -OCH_Three, -OCH₂CH_ThreeIs preferred.
[0033]
In the formula (2), n is 0, 1 or 2.
[0034]
As the hydrolyzable silane (B) of the formula (2), the following can be exemplified. Si (OCH_Three)_Four, Si (OCH₂CH_Three)_Four, Si (OCH₂CH₂CH_Three)_Four, Si (OCH₂CH₂CH₂CH_Three)_Four, CH_ThreeSi (OCH_Three)_Three, CH_ThreeSi (OCH₂CH_Three)_Three, CH_ThreeSi (OCH₂CH₂CH_Three)_Three, CH_ThreeSi (OCH₂CH₂CH₂CH_Three)_Three, (CH_Three)₂Si (OCH_Three)₂, (CH_Three)₂Si (OCH₂CH_Three)₂, (CH_Three)₂Si (OCH₂CH₂CH_Three)₂, (CH_Three)₂Si (OCH₂CH₂CH₂CH_Three)₂,
[Chemical 9]

[0035]
Of these, particularly preferred is Si (OCH_Three)_Four, Si (OCH₂CH_Three)_Four, CH_ThreeSi (OCH_Three)_Three, CH_ThreeSi (OCH₂CH_Three)_ThreeAnd partial hydrolysates thereof.
[0036]
When the hydrolyzable silane (B) or its partial hydrolyzate of the formula (2) is mixed with the hydrolyzable silane (A) or its partial hydrolyzate containing the nitrogen atom-containing organic group, the mixture The ratio is a ratio of hydrolyzable silane (B) or a partial hydrolyzate thereof from 5 to 200 parts by weight with respect to 100 parts by weight of the hydrolyzable silane (A) or a partial hydrolyzate thereof containing a nitrogen atom-containing organic group. More preferably, the amount of hydrolyzable silane (B) or a partially hydrolyzed product thereof is 10 to 150 parts by weight. If this amount exceeds 200 parts by weight, the stability of the liquid deteriorates.
[0037]
When the hydrolyzable silane (A), (B) or a partial hydrolyzate thereof is used to obtain the organosilicon compound of the present invention, water is mainly used as a solvent. Alcohols, esters, ketones, and glycols, which are organic solvents that dissolve in water, can be used by adding them to water. Examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol, 1-propyl alcohol, and 2-propyl alcohol, esters such as methyl acetate, ethyl acetate, and ethyl acetoacetate, ketones such as acetone and methyl ethyl ketone, glycerin, and diethylene glycol. And the like.
[0038]
The amount of the solvent is preferably 400 to 5000 parts by weight with respect to 100 parts by weight of the raw material silane. More preferably, it is 1000-3000 weight part. If the amount of the solvent is too small, the reaction may proceed too much and the system may not be uniform. In addition, the storage stability of the liquid may deteriorate. On the other hand, if it is too much, it may be economically disadvantageous.
[0039]
The amount of water in the solvent is preferably 5 to 50 in terms of a water / raw material silane molar ratio. When this molar ratio is less than 5, hydrolysis hardly proceeds completely, and the stability of the liquid may be deteriorated. On the other hand, if it exceeds 50, an economical disadvantage may occur.
[0040]
As the reaction method, (1) a method of dropping mixed silane into water or an organic solvent containing water in an amount more than necessary for hydrolysis, and (2) dropping water into mixed silane or organic solvent-containing mixed silane. (3) The hydrolyzable silane (B) or a partial hydrolyzate thereof is dropped into water or an organic solvent containing water in an amount more than necessary for hydrolysis, and then a nitrogen atom-containing organic group is added. Method of dropping hydrolyzable silane (A) or partial hydrolyzate contained therein, (4) Hydrolyzable silane (A) containing a nitrogen atom-containing organic group or partial hydrolyzate thereof in water or hydrolyzed Examples of the method include dropping a hydrolyzable silane (B) or a partially hydrolyzed product thereof into an organic solvent containing an amount of water more than necessary, and then adding the hydrolyzable silane (B) or a partially hydrolyzed product thereof. From Notably the reaction method (1) is preferred.
[0041]
In addition, although the obtained organosilicon compound is obtained in the form of an aqueous solution, water is added or removed as necessary, and 10 to 2000 parts by weight of water with respect to 100 parts by weight of the organosilicon compound, It is preferable to form an organic silicon compound aqueous solution by adjusting the ratio to 10 to 1000 parts by weight. In this case, if the amount of water is too small, the storage stability of the organosilicon compound itself may deteriorate. Moreover, when there are too many, the amount which adds an organosilicon compound will increase and it is unpreferable in terms of cost.
[0042]
Since the organosilicon compound thus obtained is of an aqueous solution type, when the proton conductive polymer is treated, it is well-suited with the polymer, can be treated smoothly, and the polymer can be uniformly modified. In addition, there is an advantage that it is not necessary to promote hydrolysis by once immersing in boiling water after treatment, as in a methanol solution treatment of an aminoalkoxysilane monomer. Furthermore, since the treatment concentration can be increased to 10% by weight or more, the treatment efficiency can be improved. In addition, the storage stability of the organic silicon compound aqueous solution is high, and the liquid is not wasted, which is advantageous in terms of cost.
[0043]
The organosilicon compound concentration during the treatment with the proton conductive polymer is preferably 10 to 40% by weight, particularly preferably 15 to 30% by weight. If the concentration is too low, the processing efficiency may deteriorate. If the concentration is too high, the stability of the aqueous solution may deteriorate.
[0044]
In the case of treating the proton conductive polymer, it is preferable to treat the proton conductive polymer by immersing it in this organic silicon compound aqueous solution. The immersion time is preferably 1 minute to 2 hours, more preferably 1 minute to 20 minutes.
[0045]
In this case, since the treatment liquid is an aqueous solution, a short time treatment is sufficient. The treatment temperature at this time is preferably 20 to 80 ° C, more preferably 30 to 60 ° C.
[0046]
After the treatment, the target proton conductive membrane can be obtained by drying. At this time, the target proton conductive membrane is suitably produced by drying at room temperature or 30 to 80 ° C. be able to.
[0047]
Next, the second invention will be described. The second invention treats a proton conductive polymer with a water-soluble reactant obtained by cohydrolyzing / condensing a hydrolyzable silane containing a fluoroalkyl group-containing alkoxysilane, an alkyl group-containing alkoxysilane, and a nitrogen atom-containing organic group. It is. In this case, the reaction product is obtained by adding water solubility to the fluorinated alkyl group-containing silane compound itself and easily dissolves in water, so that it can impart excellent water repellency derived from the fluorinated alkyl group. Thus, methanol crossover can be prevented.
[0048]
Hereinafter, the second invention will be further described. The fluorinated alkyl group-containing alkoxysilane used is represented by the following general formula (3), and may be a partially hydrolyzed product thereof.
[0049]
[Chemical Formula 10]

[Wherein Rf is C_pF_{2p + 1}Represents a polyfluoroalkyl group represented by (p = 1 to 20), and X represents —CH.₂-, -CH₂O-, -NR^Three-, -CO₂-, -CONR^Five-, -S-, -SO_Three-Or-SO₂NR^Three-1 type or 2 types or more of bonding group (R^FiveRepresents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms), and R^Three, R^FourIs the same as above. a is an integer of 0 to 3, b is an integer of 1 to 3, and c is 0 or 1. ]
[0050]
Examples of the silane represented by the general formula (3) include the following.
In the following formula, Rf is C_pF_{2p + 1}(P is an integer from 1 to 20) and CF_Three-, C₂F_Five-, C_ThreeF₇-, C_FourF₉-, C₆F₁₃-, C₈F₁₇-, C_TenF_{twenty one}-, C₁₂F_{twenty five}-, C₁₄F₂₉-, C₁₆F₃₃-, C₁₈F₃₇-, C₂₀F₄₁-Etc. are exemplified.
Rf (CH₂)₂Si (OCH_Three)_Three,
Rf (CH₂)₂Si (OC₂H_Five)_Three,
Rf (CH₂)₂Si (OCH (CH_Three)₂)_Three,
Rf (CH₂)₂SiCH_Three(OCH_Three)₂,
Rf (CH₂)₂SiCH_Three(OC₂H_Five)₂,
Rf (CH₂)₂SiCH_Three(OCH (CH_Three)₂)₂,
Rf (CH₂)_ThreeSi (OCH_Three)_Three,
Rf (CH₂)_ThreeSi (OC₂H_Five)_Three,
Rf (CH₂)_ThreeSi (OCH (CH_Three)₂)_Three,
Rf (CH₂)_ThreeSiCH_Three(OCH_Three)₂,
Rf (CH₂)_ThreeSiCH_Three(OC₂H_Five)₂,
Rf (CH₂)_ThreeSiCH_Three(OCH (CH_Three)₂)₂,
RfNH (CH₂)₂Si (OCH_Three)_Three,
RfNH (CH₂)₂Si (OC₂H_Five)_Three,
RfNH (CH₂)₂Si (OCH (CH_Three)₂)_Three,
RfNH (CH₂)₂SiCH_Three(OCH_Three)₂,
RfNH (CH₂)₂SiCH_Three(OC₂H_Five)₂,
RfNH (CH₂)₂SiCH_Three(OCH (CH_Three)₂)₂,
RfNH (CH₂)₂NH (CH₂)₂Si (OCH_Three)_Three,
RfNH (CH₂)₂NH (CH₂)₂Si (OC₂H_Five)_Three,
RfNH (CH₂)₂NH (CH₂)₂Si (OCH (CH_Three)₂)_Three,
RfNH (CH₂)₂NH (CH₂)₂SiCH_Three(OCH_Three)₂,
RfNH (CH₂)₂NH (CH₂)₂SiCH_Three(OC₂H_Five)₂,
RfNH (CH₂)₂NH (CH₂)₂SiCH_Three(OCH (CH_Three)₂)₂,
RfCONH (CH₂)₂Si (OCH_Three)_Three,
RfCONH (CH₂)₂Si (OC₂H_Five)_Three,
RfCONH (CH₂)₂Si (OCH (CH_Three)₂)_Three,
RfCONH (CH₂)₂SiCH_Three(OCH_Three)₂,
RfCONH (CH₂)₂SiCH_Three(OC₂H_Five)₂,
RfCONH (CH₂)₂SiCH_Three(OCH (CH_Three)₂)₂,
RfSO₂NH (CH₂)₂Si (OCH_Three)_Three,
RfSO₂NH (CH₂)₂Si (OC₂H_Five)_Three,
RfSO₂NH (CH₂)₂Si (OCH (CH_Three)₂)_Three,
RfSO₂NH (CH₂)₂SiCH_Three(OCH_Three)₂,
RfSO₂NH (CH₂)₂SiCH_Three(OC₂H_Five)₂,
RfSO₂NH (CH₂)₂SiCH_Three(OCH (CH_Three)₂)₂
Of these, the following are preferable.
C₈F₁₇(CH₂)₂Si (OCH_Three)_Three,
C₈F₁₇(CH₂)₂SiCH_Three(OCH_Three)₂,
C₈F₁₇(CH₂)₂Si (OC₂H_Five)_Three,
C₈F₁₇(CH₂)₂SiCH_Three(OC₂H_Five)_Three,
C_FourF₉(CH₂)₂Si (OCH_Three)_Three,
C_FourF₉(CH₂)₂SiCH_Three(OCH_Three)₂,
C_FourF₉(CH₂)₂Si (OC₂H_Five)_Three,
C_FourF₉(CH₂)₂SiCH_Three(OC₂H_Five)₂,
C₈F₁₇CONH (CH₂)₂Si (OCH_Three)_Three
Especially C₈F₁₇(CH₂)₂Si (OCH_Three)_ThreeIs preferred.
[0051]
In the present invention, as the fluorinated alkyl group-containing alkoxysilane, in addition to the silane, a partial hydrolyzate of the silane can be used. However, in this case, at least one hydrolyzable group needs to remain. If desired, various silane mixtures may be used, or a partial hydrolyzate of mixed silanes.
[0052]
In the second invention, the hydrolyzable silane (B) of the general formula (2) described in the first invention or a partially hydrolyzed product thereof, and the general formula ( The reaction product obtained by reacting hydrolyzable silane (A) containing a nitrogen atom-containing organic group (1) or a partial hydrolyzate thereof is used.
[0053]
In this case, as the hydrolyzable silane (B) of the formula (2), those described above are used, but the following are particularly preferably used.
C_TenH_{twenty one}Si (OCH_Three)_Three,
C_TenH_{twenty one}Si (OC₂H_Five)_Three,
C_TenH_{twenty one}SiCH_Three(OCH_Three)₂,
C_TenH_{twenty one}SiCH_Three(OC₂H_Five)₂,
C₆H₁₃Si (OCH_Three)_Three,
C₆H₁₃Si (OC₂H_Five)_Three,
C₆H₁₃SiCH_Three(OCH_Three)₂,
C₆H₁₃SiCH_Three(OC₂H_Five)₂,
C_ThreeH₇Si (OCH_Three)_Three,
C_ThreeH₇Si (OC₂H_Five)_Three,
C_ThreeH₇SiCH_Three(OCH_Three)₂,
C_ThreeH₇SiCH_Three(OC₂H_Five)₂,
C₂H_FiveSi (OCH_Three)_Three,
C₂H_FiveSi (OC₂H_Five)_Three,
C₂H_FiveSiCH_Three(OCH_Three)₂,
C₂H_FiveSiCH_Three(OC₂H_Five)₂,
CH_ThreeSi (OCH_Three)_Three,
CH_ThreeSi (OC₂H_Five)_Three,
(CH_Three)₂Si (OCH_Three)₂,
(CH_Three)₂Si (OC₂H_Five)₂
Among these, especially
C_TenH_{twenty one}Si (OCH_Three)_Three,
C_TenH_{twenty one}SiCH_Three(OCH_Three)₂,
(CH_Three)₂Si (OCH_Three)₂,
(CH_Three)₂Si (OC₂H_Five)₂
Etc. are preferably used.
[0054]
In the present invention, as the alkyl group-containing alkoxysilane, in addition to the above silane, a partial hydrolyzate of the above silane can also be used.
[0055]
Further, the hydrolyzable silane (A) containing a nitrogen atom-containing organic group may be the same as described above, but the following are preferable.
H₂N (CH₂)₂Si (OCH_Three)_Three,
H₂N (CH₂)₂Si (OC₂H_Five)_Three,
H₂N (CH₂)_ThreeSi (OCH_Three)_Three,
H₂N (CH₂)_ThreeSi (OC₂H_Five)_Three,
CH_ThreeNH (CH₂)_ThreeSi (OCH_Three)_Three,
CH_ThreeNH (CH₂)_ThreeSi (OC₂H_Five)_Three,
CH_ThreeNH (CH₂)_FiveSi (OCH_Three)_Three,
CH_ThreeNH (CH₂)_FiveSi (OC₂H_Five)_Three,
H₂N (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three,
H₂N (CH₂)₂NH (CH₂)_ThreeSi (OC₂H_Five)_Three,
CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three,
CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSi (OC₂H_Five)_Three,
C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three,
C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSi (OC₂H_Five)_Three,
H₂N (CH₂)₂SiCH_Three(OCH_Three)₂,
H₂N (CH₂)₂SiCH_Three(OC₂H_Five)₂,
H₂N (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH_Three)₂,
H₂N (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OC₂H_Five)₂
Among these, especially
H₂N (CH₂)₂Si (OCH_Three)_Three,
H₂N (CH₂)₂Si (OC₂H_Five)_Three,
H₂N (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three,
H₂N (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH_Three)₂
Etc. are preferably used. These partial hydrolysates can also be used.
[0056]
Here, a reaction product of these fluorinated alkyl group-containing alkoxysilane, a nitrogen atom-containing organic group-containing hydrolyzable silane, and an alkyl group-containing alkoxysilane is obtained by co-hydrolyzing these three components in the presence of an organic acid or an inorganic acid. It can be obtained by decomposing and condensing. In view of stability, the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane are first partially hydrolyzed in the presence of an organic acid or an inorganic acid, and then the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxy It is preferably obtained by reacting a partially hydrolyzed product with silane and a hydrolyzable silane containing a nitrogen atom-containing organic group.
[0057]
Organic acids and inorganic acids used in hydrolyzing the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane include hydrochloric acid, sulfuric acid, methanesulfonic acid, formic acid, acetic acid, propionic acid, citric acid, At least one acid selected from acid and maleic acid is used, but a weak acid is preferable from the viewpoint of corrosiveness to the substrate when it is treated, and acetic acid and propionic acid are particularly preferable. The amount of the acid used is preferably 30 to 400 parts by weight, more preferably 40 to 350 parts by weight, based on 100 parts by weight of the total amount of the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane. If the amount of the acid used is too small, the hydrolysis proceeds slowly and the stability of the aqueous solution of the composition may deteriorate.
[0058]
The hydrolysis is preferably performed in a state diluted with a solvent. As the solvent, alcohol solvents are preferable, and methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-butanol and 2-methyl-2-butanol are preferable. Particularly preferred is 3-butanol. The amount of the solvent used is preferably 100 to 500 parts by weight, more preferably 200 to 100 parts by weight with respect to 100 parts by weight of the fluorinated alkyl group-containing alkoxysilane or the total amount of fluorinated alkyl group-containing alkoxysilane and alkyl group-containing alkoxysilane. 400 parts by weight. If the amount of the solvent used is too small, condensation may proceed, and if it is too large, hydrolysis may take time.
[0059]
The amount of water added to hydrolyze the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane is the molar amount of the fluorinated alkyl group-containing alkoxysilane or the total of the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane. Preferably it is 1-3 times mole amount with respect to mole amount, More preferably, it is 1.2-2.5 times mole amount. If the amount of water added is less than 1 times the molar amount, a large number of alkoxy groups may remain. On the other hand, if the amount exceeds 3 times, the condensation may proceed too much.
[0060]
As for the reaction conditions for hydrolyzing the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane, the reaction temperature is preferably 10 to 100 ° C, more preferably 60 to 90 ° C, and the reaction time is 1 to 1. The hydrolysis reaction is preferably performed in 3 hours.
[0061]
In addition, it is preferable that the ratio in the case of reacting a fluorinated alkyl group-containing alkoxysilane and an alkyl group-containing alkoxysilane is a molar ratio of 1: 0.05 to 1: 0.5. If the molar ratio of the alkyl group-containing alkoxysilane is less than 0.05, the durability may deteriorate. On the other hand, if it is larger than 0.5, the water solubility may deteriorate.
[0062]
The reaction product of the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane thus obtained is continuously reacted with a hydrolyzable silane containing a nitrogen atom-containing organic group as follows. In this case, the molar ratio of the total amount of the fluorinated alkyl group-containing alkoxysilane and the alkyl group-containing alkoxysilane to the hydrolyzable silane containing the nitrogen atom-containing organic group is 1: 0.5 to 1:20. It is preferable to react hydrolyzable silane containing a nitrogen atom-containing organic group. If the molar ratio of the hydrolyzable silane containing a nitrogen atom-containing organic group is less than 0.5, the water solubility may deteriorate. On the other hand, if it exceeds 20, water repellency may be deteriorated.
[0063]
The reaction conditions for reacting the hydrolyzable silane containing the nitrogen atom-containing organic group are preferably a reaction temperature of 60 to 100 ° C., particularly a reaction time of 1 to 3 hours.
[0064]
Since the reaction product obtained in this way is water-soluble and is an aqueous solution type, even when processing a proton-conductive polymer, it has good compatibility with the polymer and can be processed smoothly. Can be modified. Further, in this case, the processing efficiency can be improved because sufficient processing can be performed even if the processing concentration is low. In addition, the storage stability of the aqueous treatment agent solution is high, so that the solution is not wasted and the cost is advantageous.
[0065]
The proton-conducting polymer is treated with a treatment agent in which 0.1 to 10% by weight, more preferably 0.5 to 2% by weight of the water-soluble reactant thus obtained as an active ingredient is uniformly mixed with water. To do. At this time, if the concentration of the reactant is too thin, the processing efficiency may be deteriorated. Moreover, when there is too much, stability of aqueous solution may worsen.
[0066]
In the case of treating the proton conductive polymer, it is preferable to treat the proton conductive polymer by immersing it in this aqueous treating agent solution. The immersion time is preferably 1 minute to 2 hours, more preferably 1 to 20 minutes. In this case, a short time treatment is sufficient because the treatment liquid is an aqueous solution. The treatment temperature at this time is preferably 20 to 80 ° C, more preferably 30 to 60 ° C.
[0067]
After the treatment, the target proton conductive membrane can be obtained by drying. At this time, it is preferable to produce the target proton conductive membrane by drying at room temperature or 30 to 80 ° C. .
[0068]
Further, the third invention will be described. In the third invention, the organosilicon compound (D) represented by the following general formula (4) and the hydrolyzable silane (A) containing a nitrogen atom-containing organic group or a partial hydrolyzate thereof are cohydrolyzed and condensed. Is used to treat the proton conducting polymer. In this case, the reaction product (cohydrolysis condensate) is obtained by imparting water solubility to the alkylsiloxane compound itself, and easily dissolves in water, so that it can impart excellent water repellency derived from alkylsiloxane. By being able to do so, methanol crossover can be prevented.
[0069]
Hereinafter, the third invention will be described in more detail. The organosilicon compound (D) used is represented by the following general formula (4).
(R⁶)_d(R²)_eSiO_{(4-de) / 2}                    (4)
(Wherein R⁶Is an alkyl group having 1 to 6 carbon atoms, R²Is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, d is 0.75 to 1.5, e is 0.2 to 3, and 0.9 is a positive number satisfying 0.9 <d + e ≦ 4. )
[0070]
R in the above formula (4)⁶Is an alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, and an n-hexyl group, and a methyl group is particularly preferable.
[0071]
R²Is the same as that of the first invention, and includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and the like, and a methyl group and an ethyl group are preferable.
[0072]
Specific examples of such an organosilicon compound of formula (4) include the following compounds.
CH_ThreeSi (OCH_Three)_Three, CH_ThreeSi (OC₂H_Five)_Three, CH_ThreeSi (OCH (CH_Three)₂)_Three, CH_ThreeCH₂Si (OCH_Three)_Three, CH_ThreeCH₂Si (OC₂H_Five)_Three, CH_ThreeCH₂Si (OCH (CH_Three)₂)_Three, C_ThreeH₇Si (OCH_Three)_Three, C_ThreeH₇Si (OC₂H_Five)_Three, C_ThreeH₇Si (OCH (CH_Three)₂)_Three, C_FourH₉Si (OCH_Three)_Three, C_FourH₉Si (OC₂H_Five)_Three, C_FourH₉Si (OCH (CH_Three)₂)_Three, C_FiveH₁₁Si (OCH_Three)_Three, C_FiveH₁₁Si (OC₂H_Five)_Three, C_FiveH₁₁Si (OCH (CH_Three)₂)_Three, C₆H₁₃Si (OCH_Three)_Three, C₆H₁₃Si (OC₂H_Five)_Three, C₆H₁₃Si (OCH (CH_Three)₂)_Three
[0073]
In the present invention, the above various silanes may be used alone, or two or more kinds of mixtures may be used, or a partial hydrolyzate of mixed silanes may be used.
[0074]
Further, as well known in the art as the component (D), an alkoxy group-containing siloxane obtained by partially hydrolyzing and condensing the silane can be used (in this case, the number of silicon atoms in the partially hydrolyzed product is 2 to 2). 10, particularly 2 to 4). Further, the component (D) may be obtained by reacting an alkyltrichlorosilane having 1 to 6 carbon atoms with methanol or ethanol in water (in this case, the number of silicon atoms is 2 to 6, particularly 2). ~ 4, and 300 mm at 25 ° C²Having a viscosity of less than / s is preferred, especially 1 to 100 mm²Those having a viscosity of / s are preferred.
[0075]
The hydrolyzable silane (A) containing a nitrogen atom-containing organic group of the present invention is represented by the above general formula (1) of the first invention, and those described above can be used. Those are preferred.
H₂N (CH₂)₂Si (OCH_Three)_Three, H₂N (CH₂)₂Si (OCH₂CH_Three)_Three, H₂N (CH₂)_ThreeSi (OCH_Three)_Three, H₂N (CH₂)_ThreeSi (OCH₂CH_Three)_Three, CH_ThreeNH (CH₂)_ThreeSi (OCH_Three)_Three, CH_ThreeNH (CH₂)_ThreeSi (OCH₂CH_Three)_Three, CH_ThreeNH (CH₂)_FiveSi (OCH_Three)_Three, CH_ThreeNH (CH₂)_FiveSi (OCH₂CH_Three)_Three, H₂N (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three, H₂N (CH₂)₂NH (CH₂)_ThreeSi (OCH₂CH_Three)_Three, CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three, CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSi (OCH₂CH_Three)_Three, C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSi (OCH_Three)_Three, C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSi (OCH₂CH_Three)_Three, H₂N (CH₂)₂SiCH_Three(OCH_Three)₂, H₂N (CH₂)₂SiCH_Three(OCH₂CH_Three)₂, H₂N (CH₂)_ThreeSiCH_Three(OCH_Three)₂, H₂N (CH₂)_ThreeSiCH_Three(OCH₂CH_Three)₂, CH_ThreeNH (CH₂)_ThreeSiCH_Three(OCH_Three)₂, CH_ThreeNH (CH₂)_ThreeSiCH_Three(OCH₂CH_Three)₂, CH_ThreeNH (CH₂)_FiveSiCH_Three(OCH_Three)₂, CH_ThreeNH (CH₂)_FiveSiCH_Three(OCH₂CH_Three)₂, H₂N (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH_Three)₂, H₂N (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH₂CH_Three)₂, CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH_Three)₂, CH_ThreeNH (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH₂CH_Three)₂, C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH_Three)₂, C_FourH₉NH (CH₂)₂NH (CH₂)_ThreeSiCH_Three(OCH₂CH_Three)₂
[0076]
Among these, in particular, N- (2-aminoethyl) -3-aminopropyltrimethoxysilashi, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3 -Aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3 -Aminopropylmethyldiethoxysilane or the like is preferably used.
In addition, these partial hydrolysates may be sufficient.
[0077]
The use ratio of the components (D) and (A) is 0.5 to 49 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the component (D). When the component (A) is less than 0.5 parts by weight, the water solubility becomes weak and the stability when it is made into an aqueous solution is deteriorated. On the other hand, when the component (A) exceeds 49 parts by weight, the water repellency and the long-term water absorption preventive property are deteriorated, or yellowing becomes severe when treated on a neutral substrate.
[0078]
In terms of mole, it is preferable that the Si atom of the component (A) is 0.01 to 0.3 mol, particularly 0.05 to 0.2 mol, relative to 1 mol of the Si atom of the (D) component. .
[0079]
These components (D) and (A) may be cohydrolyzed in the presence of an organic acid or an inorganic acid. In this case, the component (D) is first hydrolyzed in the presence of an organic acid or an inorganic acid, the hydrolyzate of the component (D) and the component (A) are mixed, and in the presence of an organic acid or an inorganic acid, Further hydrolysis is preferred.
[0080]
Examples of the organic acid and inorganic acid used when hydrolyzing the component (D) include at least selected from hydrochloric acid, sulfuric acid, methanesulfonic acid, formic acid, acetic acid, propionic acid, citric acid, oxalic acid, maleic acid, and the like. One acid is used, and particularly preferred are acetic acid and propionic acid. The acid is preferably used in an amount of 2 to 40 parts by weight, particularly 3 to 15 parts by weight per 100 parts by weight of component (D).
[0081]
The hydrolysis is preferably carried out in a state diluted with a solvent appropriately. As the solvent, alcohol solvents are preferable, and methanol, ethanol, isopropyl alcohol, and tertiary butyl alcohol are particularly preferable. The amount of the solvent used is preferably 50 to 300 parts by weight, particularly 70 to 200 parts by weight, based on 100 parts by weight of component (D). If the amount of solvent used is too small, condensation may proceed, and if too much, hydrolysis may take time.
[0082]
Moreover, the amount of water added to hydrolyze the component (D) is preferably 0.5 to 4 mol, particularly 1 to 3 mol relative to 1 mol of the component (D). If the amount of water added is too small, a large number of alkoxy groups may remain, and if too much, condensation may proceed excessively.
[0083]
(D) As for the reaction conditions at the time of hydrolyzing a component, 10-40 degreeC of reaction temperature is good, and especially 20-30 degreeC is good, and it is good to make it hydrolyze in 1 to 3 hours of reaction time.
[0084]
The hydrolyzate of component (D) obtained above is reacted with component (A). The reaction conditions are preferably a reaction temperature of 60 to 100 ° C. and a reaction time of 1 to 3 hours. After completion of the reaction, the temperature is raised to the boiling point of the solvent or higher, and the alcohol solvent is distilled off. In this case, it is preferable to distill off so that the content of all alcohols in the system (alcohol as a reaction solvent and alcohol as a by-product) is 30% by weight or less, particularly 10% by weight or less. When a large amount of alcohol is contained, when diluted with water, it may become cloudy or gel, and storage stability may also be reduced. The reaction product that can be produced by the above method has a viscosity at 25 ° C. of 5 to 2000 mm.²/ S, especially 50-500mm²/ S is preferable. If the viscosity is too high, workability and storage stability may decrease, and water solubility may decrease. The weight average molecular weight is preferably in the range of 500 to 5,000, particularly 800 to 2,000.
[0085]
Since the reaction product obtained in this manner is an aqueous solution type, the proton conductive polymer can be treated well and can be treated smoothly, and can be uniformly modified. Further, in this case, the processing efficiency can be improved because sufficient processing can be performed even if the processing concentration is low. In addition, the storage stability of the aqueous treatment agent solution is high, so that the solution is not wasted and the cost is advantageous.
[0086]
The proton conducting polymer is treated with a treating agent in which 0.01 to 20% by weight, more preferably 1.0 to 10% by weight, of the water-soluble reactant thus obtained as an active ingredient is uniformly mixed with water. Is preferred. At this time, if the concentration of the reactant is too thin, the processing efficiency may be deteriorated. On the other hand, if the concentration is too high, the stability of the aqueous solution may deteriorate.
[0087]
The treatment of the proton conductive polymer is preferably carried out by immersing the proton conductive polymer in this aqueous treating agent solution. The immersion time is preferably 1 minute to 2 hours, more preferably 1 to 20 minutes. In this case, since the treatment liquid is an aqueous solution, a short time treatment is sufficient. The treatment temperature at this time is preferably 20 to 80 ° C, more preferably 30 to 60 ° C.
[0088]
After the treatment, the target proton conductive membrane can be obtained by drying. At this time, the target proton conductive membrane can be produced by drying at room temperature or 30 to 80 ° C. .
[0089]
The proton conductive membrane for an electrolyte of the present invention is used as a proton conductive membrane of a fuel cell, being sandwiched between a fuel electrode and an oxidant electrode, similarly to a known proton conductive membrane. In this case, the configuration of the fuel cell can be a known configuration except that the proton conductive membrane of the present invention is used.
[0090]
【Example】
  EXAMPLES Hereinafter, although a synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example..
[0097]
Synthesis of aqueous treatment solution
    [Synthesis example1]
  Into a 0.5 L four-necked flask equipped with a stirrer, condenser, thermometer and dropping funnel₈F₁₇(CH₂)₂Si (OCH_Three)_Three48.0 g (0.085 mol), (CH_Three)₂Si (OCH_Three)₂2.0 g (0.009 mol), 3-butanol 169 g, acetic acid 14.2 g (0.237 mol) and water 2.6 g (0.142 mol) were added and stirred, and heated until 3-butanol was refluxed. After reacting for 2 hours, H₂N (CH₂)₂HN (CH₂)_ThreeSi (OCH_Three)_Three21.0 g (0.095 mol) was added dropwise, and the mixture was further reacted for 1 hour under reflux of 3-butanol to obtain a pale yellow transparent solution. When the nonvolatile content was measured under the conditions of 105 ° C./3 hours, it was 20.2%. This was diluted to 2% by weight with water to obtain a treating agent aqueous solution-1.
[0098]
    [Synthesis example2]
  Into a 1.0 L four-necked flask equipped with a stirrer, condenser, thermometer and dropping funnel_FourF₉(CH₂)₂SiCH_Three(OCH_Three)₂80.0 g (0.227 mol), (CH_Three)₂Si (OCH_Three)₂4.0 g (0.033 mol), CH_ThreeSi (OCH_Three)_Three9.93 g (0.073 mol), 68 g of methanol, 30.0 g (0.5 mol) of acetic acid and 9 g (0.499 mol) of water were added and stirred, and heated until methanol was refluxed. After reacting for 2 hours, H₂N (CH₂)₂HN (CH₂)_ThreeSi (OCH₂CH_Three)_Three73.7 g (0.333 mol) was added dropwise, and the mixture was further reacted for 2 hours under methanol reflux. Further, an ester adapter was attached, the internal temperature was raised to 110 ° C., methanol was removed, and a yellow paste was obtained. Water was added here, and it adjusted so that a non volatile matter might be 2 weight%. What was obtained was a transparent aqueous solution. This was designated treating agent aqueous solution-2.
[0099]
    [Synthesis example3]
  In a 500 ml four-necked flask equipped with a condenser, thermometer and dropping funnel, 85 g of methyltrimethoxysilane oligomer (0.37 mol in terms of dimer), 154 g of methanol and 5.1 g of acetic acid were placed and stirred. 6.8 g (0.37 mol) of water was added and stirred at 25 ° C. for 2 hours. N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (8.9 g, 0.04 mol) was added dropwise thereto. Then, after heating to the reflux temperature of methanol and reacting for 1 hour, the methanol was distilled off with an ester adapter until the internal temperature reached 110 ° C., and the viscosity was 71 mm.²81 g of a pale yellow transparent solution of / s was obtained (weight average molecular weight 1100). This was diluted with water to 5 wt% to obtain a pale yellow transparent treatment agent aqueous solution-3.
[0100]
    [Synthesis example4]
  Synthesis example except that N- (2-aminoethyl) -3-aminopropyltrimethoxysilane was changed to 17.7 g (0.08 mol) of 3-aminopropyltriethoxysilane.3The reaction is similar to²90 g of a pale yellow transparent solution of / s was obtained (weight average molecular weight 1300). This was diluted with water to 5% by weight to obtain a transparent treating agent aqueous solution-4.
[0101]
Proton conductive polymer used
A commercially available Nafion membrane (Nafion 117 @ film) having a thickness of 190 μm was prepared as a membrane made of a proton conductive polymer to be used, treated in boiling water for 1 hour, and immersed in 10% nitric acid for several hours. Furthermore, after sufficiently washing with pure water, it was stored in pure water. This was taken out before processing and used for the reaction.
[0102]
    [Example 1]
  The Nafion membrane described above was taken out from the pure water, and the water on the membrane surface was sufficiently absorbed with filter paper.Treatment agent aqueous solution-1By soaking in the room temperature for 1 minute and then drying at room temperatureXA proton conductive membrane of 1-1 was prepared. About the obtained proton conductive membrane, methanol permeability and electrical resistance were measured.
[0103]
First, two circular cells having a diameter of 30 mm were prepared. One cell contained a 10% aqueous methanol solution, and the other cell contained pure water. A proton conductive polymer membrane was inserted into these two cells and allowed to stand at room temperature for a certain time. Thereafter, the methanol concentration on the cell side containing pure water was measured by gas chromatography to measure methanol permeability.
[0104]
The membrane of the sample was taken out from the pure water after a lapse of a certain time, drained, and measured for methanol permeability. The permeability of methanol is shown in Table 1 as a relative value with Nafion as 1.
[0105]
10cm²Were prepared, and a platinum electrode was attached to one side thereof. A proton conductive membrane was inserted between these two cells, and the value at 1 kHz was measured with an impedance analyzer to obtain the electrical resistance of the membrane. The obtained results are shown in Table 1.
[0118]
    [Example2]
  Example 1Treatment aqueous solution-1 was changed to the treating agent aqueous solution-2, but the above-mentioned sampleXSample XII-1 was produced in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0119]
    [Example3]
  Example 1Treatment aqueous solutionThe sample described above except that -1 was changed to the treatment agent aqueous solution-3.XSample XIII-1 was prepared in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0120]
    [Example4]
  Example 1Treatment aqueous solutionThe sample described above except that -1 was changed to the treatment agent aqueous solution-4.XSample XIV-1 was produced in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0121]
    [Comparative Example 1]
  Example 1Treatment aqueous solution-1 was changed to 3-aminopropyltrimethoxysilane in 1% methanol solution.XSample VIII-1 was produced in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0122]
    [Comparative Example 2]
  The sample described above except that 3-aminopropyltrimethoxysilane in Comparative Example 1 was changed to N- (2-aminoethyl) -3-aminopropyltrimethoxysilane.XSample IX-1 was produced in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0123]
    [Comparative Example 3]
  The sample described above except that 3-aminopropyltrimethoxysilane of Comparative Example 1 was changed to a total 1% methanol mixture of 0.5% 3-aminopropyltrimethoxysilane and 0.5% tetraethoxysilane.XSample X-1 was produced in the same manner as I-1. The obtained proton conductive membrane was measured for methanol permeability and electrical resistance in the same manner as in Example 1. The results are shown in Table 1.
[0124]
[Comparative Examples 4 to 6]
Furthermore, methanol permeability and electrical resistance of single Nafion 117, 1135, and 1035 were examined by the same method as described above. The results are shown in Table 1.
[0125]
[Table 1]

[0126]
As shown in Table 1, in the proton conductive membrane according to the production method of the present invention, the electrical resistance (impedance) of the membrane is in the range of about several times that of a single Nafion. From this, it was clarified that the proton conductive membrane of the present invention can greatly reduce methanol permeability while maintaining proton conductivity to some extent.
[0127]
【The invention's effect】
According to the present invention, there is provided a proton conductive membrane for an electrolyte of a fuel cell that makes it possible to suppress crossover of methanol while maintaining proton conductivity. In addition, by using the proton conductive membrane of the present invention, it is possible to obtain a fuel cell that is small in size, high in performance, and capable of supplying a stable output, and its industrial value is tremendous.

Claims (12)

A proton conductive polymer for an electrolyte of a fuel cell is represented by the following general formula (1)
YR ¹ _m SiR ² _3-m (1)
(In the formula, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ² is an alkoxy group or acyloxy group having 1 to 4 carbon atoms, Y is a nitrogen atom-containing organic group, m Is 0 or 1.)
A hydrolyzable silane (A) or a partially hydrolyzed product thereof containing a nitrogen atom-containing organic group represented by the following general formula (2):
R ³ _n SiR ⁴ _4-n (2)
(In the formula, R ³ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁴ is an alkoxy group or acyloxy group having 1 to ⁴ carbon atoms, and n is 0, 1 or 2.)
A hydrolyzable silane (B) or a partial hydrolyzate thereof, represented by the following general formula (3)

[Wherein, Rf represents a polyfluoroalkyl group represented by C _p F _{2p + 1} (p = 1 to 20), and X represents —CH ₂ —, —CH ₂ O—, —NR ³ —, —CO _2- , —CONR ⁵ —, —S—, —SO ₃ — or —SO ₂ NR ³ —, one or more bonding groups (R ⁵ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms). R ³ and R ⁴ are the same as above. a is an integer of 0 to 3, b is an integer of 1 to 3, and c is 0 or 1. ]
A fluorinated alkyl group-containing alkoxysilane represented by the above or a partially hydrolyzed product thereof (C) and a water-soluble treatment agent as a main component,
The proton conductive polymer is a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton, and the sulfonic acid group and / or the carboxyl group interacts with the hydrolyzable silane (A). A proton conductive membrane for an electrolyte of a fuel cell, characterized by forming a salt. Hydrolyzable silane (A) of formula (1)
H ₂ N (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ,
H ₂ N (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ ,
H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₃
Or H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ SiCH ₃ (OCH ₃ ) ₂
The proton conductive membrane according to claim 1, wherein: The hydrolyzable silane (B) of formula (2)
C ₁₀ H ₂₁ Si (OCH ₃ ) ₃ ,
C ₁₀ H ₂₁ SiCH ₃ (OCH ₃ ) ₂ ,
(CH ₃ ) ₂ Si (OCH ₃ ) ₂
Or (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂
The proton conductive membrane according to claim 1 or 2, wherein The fluorinated alkyl group-containing alkoxysilane (C) of the formula (3) is
C ₈ F ₁₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ,
C ₈ F ₁₇ (CH ₂ ) ₂ SiCH ₃ (OCH ₃ ) ₂ ,
C ₈ F ₁₇ (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ ,
C ₈ F ₁₇ (CH ₂ ) ₂ SiCH ₃ (OC ₂ H ₅ ) ₃ ,
C ₄ F ₉ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ,
C ₄ F ₉ (CH ₂ ) ₂ SiCH ₃ (OCH ₃ ) ₂ ,
C ₄ F ₉ (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ ,
C ₄ F ₉ (CH ₂ ) ₂ SiCH ₃ (OC ₂ H ₅ ) ₂
Or C ₈ F ₁₇ CONH (CH ₂ ) ₂ Si (OCH ₃ ) ₃
The proton conductive membrane according to claim 1, 2 or 3.   The component (C) and the component (B) are reacted at a molar ratio of 1: 0.05 to 1: 0.5, the total amount of the component (C) and the component (B), and the component (A) 5. The proton conductive membrane according to claim 1, wherein a reaction product obtained by reacting at a molar ratio of 1: 0.5 to 1:20 is used.   6. The proton conductive membrane according to any one of claims 1 to 5, wherein the proton conductive polymer is treated with a water-soluble treatment agent comprising 0.1 to 10% by weight of a reactant and 99.9 to 90% by weight of water. A proton conductive polymer for an electrolyte of a fuel cell is represented by (D) the following general formula (4)
(R ⁶ ) _d (R ² ) _e SiO _{(4-de) / 2} (4)
Wherein R ⁶ is an alkyl group having 1 to ⁶ carbon atoms, R ² is an alkoxy group having 1 to 4 carbon atoms or an acyloxy group, d is 0.75 to 1.5, and e is 0.2 to 3 And a positive number satisfying 0.9 <d + e ≦ 4.)
And 100 parts by weight of an organosilicon compound represented by the following general formula (1)
YR ¹ _m SiR ² _3-m (1)
(Wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ² is the same as above, Y is a nitrogen atom-containing organic group, and m is 0 or 1).
A hydrolyzable silane (A) containing a nitrogen atom-containing organic group represented by the formula: 0.5 to 49 parts by weight of a hydrolyzable silane (A) or a partially hydrolyzed product thereof in the presence of an organic acid or inorganic acid Processed by
The proton conductive polymer is a polymer containing at least one of a sulfonic acid group and a carboxyl group and a fluororesin skeleton, and the sulfonic acid group and / or the carboxyl group interacts with the hydrolyzable silane (A). A proton conductive membrane for an electrolyte of a fuel cell, characterized by forming a salt. 8. The proton conductive membrane according to claim 7, wherein R ^{6 of} component (D) is a methyl group. (A) The hydrolyzable silane containing the nitrogen atom-containing organic group of the component is

The proton conductive membrane according to claim 7 or 8, wherein:   Use of a reaction product obtained by hydrolyzing component (D) in the presence of an organic acid or inorganic acid and an alcohol, then reacting with component (A), and then removing the alcohol from outside the system. 10. The proton conductive membrane according to any one of 9 above.   11. The proton conductive membrane according to claim 1, which is doped with an acid.   A fuel cell comprising an electrolyte membrane and a fuel electrode and an oxidizer electrode sandwiching the electrolyte membrane, wherein the electrolyte membrane includes the proton conductive membrane according to any one of claims 1 to 11. Fuel cell.