JP2004018676A - Fluorine-containing polymer, producing method of the same, fluorine-containing polymer derivative and fluorine-containing molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorine-containing polymer having excellent moldability, and its molding. <P>SOLUTION: The fluorine-containing polymer is obtained by polymerizing a perfluorovinyl ether sulfonic acid derivative represented by formula (I) wherein Y<SP>1</SP>is a halogen atom or a perfluoroalkyl group; Y<SP>2</SP>is a halogen atom; A<SP>1</SP>is -SO<SB>2</SB>X<SP>1</SP>[wherein X<SP>1</SP>is a halogen atom, -OM<SP>1</SP>[wherein M<SP>1</SP>is a hydrogen atom, NR<SP>3</SP>R<SP>4</SP>R<SP>5</SP>R<SP>6</SP>(wherein R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>and R<SP>6</SP>are each a hydrogen atom, or a 1-4C alkyl group), or an alkali metal], -OM<SP>2</SP><SB>1/2</SB>[wherein M<SP>2</SP>is an alkaline earth metal], or -NR<SP>1</SP>R<SP>2</SP>[R<SP>1</SP>and R<SP>2</SP>are each a hydrogen atom, an alkali metal, a sulfonyl-containing group, or an alkyl group]], or -COY<SP>3</SP>[wherein Y<SP>3</SP>is a hydroxy group, -NR<SP>7</SP>R<SP>8</SP>[wherein R<SP>7</SP>and R<SP>8</SP>are each a hydrogen atom, an alkali metal, an alkyl group, or a sulfonyl-containing group], or a 1-4C alkoxyl group]. <P>COPYRIGHT: (C)2004,JPO

Description

【００１３】
（式中、Ｙ^１は、ハロゲン原子又はパーフルオロアルキル基を表す。Ｙ^２は、ハロゲン原子を表す。ｎは、０〜３の整数を表す。ｎ個のＹ^１は、同一であってもよいし異なっていてもよい。ｍは、１〜５の整数を表す。ｍ個のＹ^２は、同一であってもよいし異なっていてもよい。Ａ^１は、−ＳＯ_２Ｘ^１又は−ＣＯＹ^３を表す。Ｘ^１は、ハロゲン原子、−ＯＭ^１、−ＯＭ^２ _１／２又は−ＮＲ^１Ｒ^２を表し、Ｍ^１は、水素原子、ＮＲ^３Ｒ^４Ｒ^５Ｒ^６又はアルカリ金属を表し、Ｍ^２は、アルカリ土類金属を表し、Ｒ^１及びＲ^２は、同一又は異なって、水素原子、アルカリ金属、スルホニル含有基若しくはアルキル基を表し、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は、同一又は異なって、水素原子若しくは炭素数１〜４のアルキル基を表す。Ｙ^３は、ヒドロキシル基、−ＮＲ^７Ｒ^８又は炭素数１〜４のアルコキシル基を表す。Ｒ^７及びＲ^８は、同一又は異なって、水素原子、アルカリ金属、アルキル基若しくはスルホニル含有基を表す。）で表されるパーフルオロビニルエーテル誘導体を重合して得られる含フッ素ポリマーであって、２７０℃、歪み０．１〜３０％の測定条件による溶融動的粘弾性測定において、下記条件（ａ）及び下記条件（ｂ）を満たすものであることを特徴とする含フッ素ポリマーである。
（ａ）０．１ｒａｄ／秒における溶融粘度が５０００Ｐａ・ｓ以上。
（ｂ）０．１〜１ｒａｄ／秒におけるｔａｎδが２〜５０。
【００１４】
本発明は、上記含フッ素ポリマーを製造することよりなる含フッ素ポリマー製造方法であって、上記一般式（Ｉ）で表されるパーフルオロビニルエーテル誘導体を追加仕込みしながら重合反応を行うことを特徴とする含フッ素ポリマー製造方法である。
【００１５】
本発明は、上記含フッ素ポリマーにアルカリ加水分解又は酸処理を行うことより得られるものであり、金属塩を形成していてもよいスルホン酸基を有することを特徴とする含フッ素ポリマー誘導体である。
【００１６】
本発明は、上記含フッ素ポリマー、及び／又は、上記含フッ素ポリマー誘導体からなるものであることを特徴とする含フッ素成形体である。
本発明は、上記含フッ素ポリマーを用いて成形した成形体にアルカリ加水分解又は酸処理を行うことより得られる含フッ素成形体であって、金属塩を形成していてもよいスルホン酸基を有するものであることを特徴とする含フッ素成形体である。
以下に本発明を詳細に説明する。
【００１７】
本発明の含フッ素ポリマーは、２７０℃での溶融動的粘弾性測定において、０．１〜１ｒａｄ／秒におけるｔａｎδが、２以上であるものである。
【００１８】
上記ｔａｎδは、粘性と弾性との相対的なバランスの指標である。上記ｔａｎδの値が大きいと、粘性と弾性とのバランスが粘性側にシフトし、力を加えたときに生じた変形を保とうとする傾向が強く、成形性が良好である。また、上記ｔａｎδの値が小さいと、粘性と弾性とのバランスが弾性側にシフトし、成形後、冷却する際に弾性収縮が起こりやすくなり、力を加える前の状態に戻ろうとする傾向が強くなる。極端にｔａｎδが小さいと、得られる成形体表面に凹凸が生じやすい。本発明では、ｔａｎδが２．０未満のときに特にこの傾向が強いことを見出した。好ましい下限は、２．２である。ｔａｎδは、上記範囲内であれば特に限定されず、例えば、５０以下であってよい。
【００１９】
上記含フッ素ポリマーは、成形温度において、０．１ｒａｄ／秒における溶融粘度が５０００Ｐａ・ｓ以上であるものである。５０００Ｐａ・ｓ未満であると、得られる成形体の機械的強度が低下する。好ましい下限は、１００００Ｐａ・ｓ、より好ましい下限は、２００００Ｐａ・ｓ、さらに好ましい下限は、３００００Ｐａ・ｓである。上記溶融粘度は、上記範囲内であれば特に限定されないが、成形性を維持する点から、例えば、１０００００Ｐａ・ｓ以下とすることができる。
【００２０】
上記溶融粘度は、値が大きいと、一般に、分子量が高い。分子量が高いと、一般に、得られる成形体の機械的強度を向上させることができる。
上記分子量は、メルトフローレート〔ＭＦＲ〕と関係づけられる。
上記ＭＦＲは、一定温度及び一定加重の条件下、規定の直径及び長さの筒から押し出される上記含フッ素ポリマーの溶融体の流出速度であり、ＡＳＴＭ　Ｄ　３１５９に準拠して測定して得られる値である。上記ＭＦＲが大きいほど、一般に低分子量であるといえる。
上記ＭＦＲは、得られた含フッ素ポリマーが充分な機械的強度を有するためには、１０ｇ／１０分以下であることが好ましい。より好ましい上限は、６ｇ／１０分である。
【００２１】
上記溶融粘度は、値が大きいと、上述のように一般にポリマー鎖が長く、従来、成形性が悪化すると考えられてきた。しかしながら、本発明は、溶融粘度が高くても、上述のｔａｎδの条件を満たせば、上記含フッ素ポリマーは成形性に優れ、滑らかな表面を有する含フッ素成形体を得ることができることを明らかにしたものである。従って、本発明の含フッ素ポリマーは、成形性と得られる含フッ素成形体の機械的強度とを両立することができる。
【００２２】
上記ｔａｎδ及び上記溶融粘度は、溶融動的粘弾性測定により得られる値である。上記溶融動的粘弾性測定は、上記含フッ素ポリマーに、正弦周期で大きさが変化する歪みを加え、歪みに対して生じる機械的応力の応答を調べる測定法である。許容される上記歪みの範囲は、一般に、測定対象が線型粘弾性を表す範囲である。上記測定対象が上記含フッ素ポリマーである場合、歪みは０．１〜３０％の範囲である。
本明細書において、上記歪みの変化周期を「周波数」ということがある。上述の「０．１〜１ｒａｄ／秒」及び「０．１ｒａｄ／秒」なる数値は、周波数である。
【００２３】
上記含フッ素ポリマーは、少なくとも上記一般式（Ｉ）で表されるパーフルオロビニルエーテル誘導体を重合して得られるものである。
【００２４】
上記一般式（Ｉ）におけるｎは、０〜３の整数を表す。上記ｎは、好ましくは、０又は１であり、より好ましくは、０である。上記一般式（Ｉ）におけるｍは、１〜５の整数を表す。好ましくは、２である。
【００２５】
上記一般式（Ｉ）におけるＹ^１は、ハロゲン原子又はパーフルオロアルキル基を表す。ｎ個のＹ^１は、同一であってもよいし、異なっていてもよい。Ｙ^２は、ハロゲン原子を表す。ｍ個のＹ^２は、同一であってもよいし、異なっていてもよい。上記Ｙ^１及び上記Ｙ^２のハロゲン原子としては特に限定されず、フッ素原子、塩素原子、臭素原子、ヨウ素原子の何れであってもよいが、好ましくは、フッ素原子である。上記パーフルオロアルキル基としては特に限定されず、例えば、トリフルオロメチル基、ペンタフルオロエチル基等が挙げられる。好ましくは、Ｙ^１は、トリフルオロメチル基であり、Ｙ^２は、フッ素原子である。
【００２６】
上記一般式（Ｉ）におけるＡは、−ＳＯ_２Ｘ^１又は−ＣＯＹ^３を表す。
上記Ｘ^１は、ハロゲン原子、−ＯＭ^１、−ＯＭ^２ _{１ ／２}又は−ＮＲ^１Ｒ^２を表す。上記Ｍ^１は、水素原子、ＮＲ^３Ｒ^４Ｒ^５Ｒ^６又はアルカリ金属を表し、Ｒ^１及びＲ^２は、同一又は異なって、水素原子、アルカリ金属、スルホニル含有基若しくはアルキル基を表し、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は、同一又は異なって、水素原子若しくは炭素数１〜４のアルキル基を表す。上記Ｍ^２は、アルカリ土類金属を表す。上記スルホニル含有基は、スルホニル基を有する含フッ素アルキル基であり、末端に置換基を有していてもよい含フッ素アルキルスルホニル基等が挙げられ、このようなものとしては、−ＳＯ_２Ｒ_ｆ ^４Ｚ（Ｒ_ｆ ^４は、含フッ素アルキレン基を表し、Ｚは、１価の有機基を表す。）等が挙げられる。上記Ｚとしては、例えば、−ＳＯ_２Ｆ、−ＳＯ_２（ＮＨＳＯ_２Ｒ_ｆ ^４ＳＯ_２）_ｋＮＨＳＯ_２Ｆ（Ｒ_ｆ ^４は上記の通り。ｋは、１以上の整数を表す。）等が挙げられる。
【００２７】
上記Ｘ^１のハロゲン原子としては、上記Ｙ^１及び上記Ｙ^２と同じものが挙げられるが、上記Ｘ^１、上記Ｙ^１及び上記Ｙ^２は、同一であってもよいし、異なっていてもよい。上記アルカリ金属としては特に限定されず、例えば、Ｌｉ、Ｎａ、Ｋ、Ｃｓ等が挙げられる。上記アルカリ土類金属としては特に限定されず、例えば、Ｍｇ、Ｃａ等が挙げられる。上記アルキル基としては特に限定されず、例えば、メチル基、エチル基等が挙げられる。好ましくは、上記Ｘ^１は、フッ素原子である。上記Ｙ^３は、ヒドロキシル基、−ＮＲ^７Ｒ^８又は炭素数１〜４のアルコキシル基を表す。上記Ｒ^７及びＲ^８としては、上記Ｒ^１及びＲ^２と同じもの等が挙げられ、上記Ｒ^１、Ｒ^２、Ｒ^７及びＲ^８は、同一であってもよいし、異なっていてもよい。
【００２８】
本発明の含フッ素ポリマーは、上記一般式（Ｉ）におけるＹ^１がトリフルオロメチル基であり、Ｙ^２がフッ素原子であり、ｎが０又は１であり、ｍが２であり、Ｘ^１がフッ素原子であるものであることが好ましい。
【００２９】
上記含フッ素ポリマーは、上記パーフルオロビニルエーテル誘導体とエチレン性モノマーとを重合して得られる２元以上の共重合体であることが好ましい。
【００３０】
上記エチレン性モノマーは、上記パーフルオロビニルエーテル誘導体と重合可能なもののうち、電離可能な電離性官能基を有しないものである。上記電離性官能基としては特に限定されず、例えば、スルホン酸基、カルボキシル基、塩を形成しているスルホン酸基、塩を形成しているカルボキシル基等が挙げられる。上記「塩を形成している」ものは、１価若しくは２価の陽イオンを形成することができる原子又は原子団が水素原子の代わりに結合したものである。
【００３１】
また、上記塩を形成しているスルホン酸基及び上記塩を形成しているカルボキシル基は、液状溶媒中、特に水又は水溶性溶剤を含む液状溶媒中において、イオン化するものであってもよい。上記１価若しくは２価の陽イオンを形成することができる原子又は原子団としては特に限定されず、例えば、上述のアルカリ金属；上述のアルカリ土類金属；アンモニウムイオン等が挙げられる。これらは、上記含フッ素ポリマーの１分子中、及び／又は、上記含フッ素ポリマーの複数の分子間において、同一であってもよいし、異なっていてもよい。
【００３２】
上記エチレン性モノマーとしては特に限定されず、例えば、下記一般式
ＣＦ_２＝ＣＦ−Ｒ_ｆ ^１
（式中、Ｒ_ｆ ^１は、フッ素原子、塩素原子、Ｒ_ｆ ^２又はＯＲ_ｆ ^２を表し、Ｒ_ｆ ^２は、炭素数１〜９のエーテル酸素を有していてもよい直鎖状又は分岐状のパーフルオロアルキル基を表す。）で表されるパーハロエチレン性単量体、下記一般式
ＣＨＸ^１＝ＣＦＸ^２
（式中、Ｘ^１は、水素原子又はフッ素原子を表し、Ｘ^２は、水素原子、フッ素原子、塩素原子、Ｒ_ｆ ^３又はＯＲ_ｆ ^３を表す。Ｒ_ｆ ^３は、炭素数１〜９のエーテル酸素を有していてもよい直鎖状又は分岐状のパーフルオロアルキル基を表す。）で表される水素含有フルオロエチレン性単量体等が挙げられる。
【００３３】
上記エチレン性モノマーは、パーハロエチレン性単量体であることが好ましく、上記エチレン性モノマーは、ＣＦ_２＝ＣＦ_２、ＣＦ_２＝ＣＦＣＦ_３、ＣＦ_２＝ＣＦ−ＯＣＦ_３、ＣＦ_２＝ＣＦ−ＯＣＦ_２ＣＦ_３及びＣＦ_２＝ＣＦ−ＯＣＦ_２ＣＦ_２ＣＦ_３からなる群より選ばれる少なくとも１つであることがより好ましい。
上記エチレン性モノマーは、ＣＦ_２＝ＣＦ_２であることが更に好ましい。
【００３４】
上記エチレン性モノマー以外にも、上記含フッ素ポリマーに種々の機能を付与するために、高分子電解質としての基本的な性能を損なわない範囲で、その他の共重合可能なモノマーを添加してもよい。上記その他の共重合可能なモノマーとしては特に限定されず、例えば、重合速度の制御、ポリマー組成の制御、弾性率等の機械的物性の制御、架橋サイトの導入等の目的に応じて共重合可能なモノマーのなかから適宜選択され、ジビニルベンゼン等の不飽和結合を２つ以上有するモノマー、シアノ基を含有するモノマー、末端にハロゲン原子を有するモノマー等が挙げられる。
【００３５】
本発明の含フッ素ポリマー製造方法は、上記含フッ素ポリマーを製造することよりなるものであって、上記一般式（Ｉ）で表されるパーフルオロビニルエーテル誘導体を追加仕込みしながら重合反応を行うことを特徴とするものである。
【００３６】
本明細書において、上記「追加仕込み」とは、重合反応に用いるパーフルオロビニルエーテル誘導体を重合開始時に反応系に添加量の全量を存在させておくのではなく、添加量の少なくとも一部分を重合開始後に断続的又は連続的に反応系に投入することを意味する。上記追加仕込みを行うことにより、ｔａｎδ及び溶融粘度を上述の範囲にすることができる結果、成形性を向上することができる。
【００３７】
上記追加仕込みは、上述のエチレン性モノマーについても行うことが好ましい。エチレン性モノマー（ａ）とパーフルオロビニルエーテル誘導体（ｂ）との両方を追加仕込みする場合、追加仕込みは、反応系内のモル濃度比を一定に保つように行うことが好ましい。上記反応系内のモル濃度比は共重合性比、得られる含フッ素ポリマーの用途等を勘案して決定するが、通常、（ａ）：（ｂ）は、１：１〜９：１の範囲であることが好ましい。
【００３８】
上記重合反応の方法としては特に限定されず、例えば、懸濁重合、乳化重合、塊状重合、溶液重合等の従来公知の重合方法を用いることができるが、工業的に多用されている点等から、懸濁重合又は乳化重合が好ましく、乳化重合がより好ましい。
上記重合反応で用いる重合開始剤の種類や濃度、重合温度、重合圧力は従来公知のものを用いることができる。
【００３９】
本発明の含フッ素ポリマー誘導体は、上述の含フッ素ポリマーにアルカリ加水分解又は酸処理を行うことより得られるものであり、金属塩を形成していてもよいスルホン酸基を有することを特徴とするものである。このとき上記含フッ素ポリマーは、上記含フッ素ポリマー誘導体の前駆体であるといえる。
上記金属塩を形成しているスルホン酸基は、塩が金属塩に限定されること以外は上述の塩を形成しているスルホン酸基と同じ概念である。
【００４０】
上記含フッ素ポリマー誘導体としては特に限定されず、例えば、下記一般式（ＩＩ）
【００４１】
【化５】

【００４２】
（Ｙ^１、Ｙ^２、ｎ及びｍは上記の通りである。ｎ個のＹ^１は、同一であってもよいし異なっていてもよく、ｍ個のＹ^２は、同一であってもよいし異なっていてもよい。Ａ^２は、−ＳＯ_２Ｘ^２又は−ＣＯＹ^４を表す。Ｘ^２は、ハロゲン原子又は−ＮＲ^１Ｒ^２を表す。Ｒ^１及びＲ^２は、同一又は異なって、水素原子、アルカリ金属、スルホニル含有基若しくはアルキル基を表す。Ｙ^４は、−ＮＲ^７Ｒ^８又は炭素数１〜４のアルコキシル基を表す。Ｒ^７及びＲ^８は、同一又は異なって、水素原子、アルカリ金属、アルキル基若しくはスルホニル含有基を表す。）で表されるパーフルオロビニルエーテル誘導体（Ｔ１）を重合して得られる含フッ素ポリマー（Ｔ）において、上記Ｘ^２又は上記Ｙ^４を上記アルカリ加水分解を行うことにより−ＯＭ^３若しくは−ＯＭ^４ _１／２（式中、Ｍ^３は水素原子又はアルカリ金属を表し、Ｍ^４はアルカリ土類金属を表す。）に変換して得られる含フッ素ポリマー誘導体（Ｕ）であってもよい。
【００４３】
上記Ｘ^２のハロゲン原子としては、上記Ｙ^１及びＹ^２と同じものが挙げられるが、好ましくは、フッ素原子である。上記Ｙ^４のアルコキシル基は、−ＯＣＨ_３であることが好ましい。上記Ａ^２としては、−ＳＯ_２Ｆ、−ＣＯＯＣＨ_３であることがこのましい。
上記Ｍ^３及び上記Ｍ^４は、上記アルカリ加水分解に用いるアルカリに由来するものである。上記Ｍ^３は上述のＭ^１と、上記Ｍ^４は上述のＭ^２と、それぞれ同じものが挙げられるが、上記Ｍ^３と上述のＭ^１、上記Ｍ^４と上述のＭ^２は、それぞれ同一であってもよいし、異なっていてもよい。
上記アルカリとしては特に限定されず、例えば、水酸化ナトリウム、水酸カリウム、炭酸ナトリウム、炭酸水素ナトリウム等が挙げられる。
【００４４】
上記含フッ素ポリマー誘導体は、上記含フッ素ポリマー誘導体（Ｕ）に酸処理を行い、上述の−ＯＭ^３又は−ＯＭ^４ _１／２を−ＯＨに変換したものであってもよい。上記酸処理に用いる酸としては特に限定されず、例えば、塩酸、硫酸、リン酸等の無機酸；ギ酸、酢酸、プロピオン酸等の有機酸等が挙げられる。
【００４５】
上記含フッ素ポリマー又は上記含フッ素ポリマー誘導体からなるものであることを特徴とする含フッ素成形体もまた、本発明の一つである。
上記含フッ素成形体を成形する方法としては特に限定されず、例えば、溶融成形法、キャスト法、含浸法等が挙げられる。上記溶融成形法は、含フッ素ポリマーを融点以上の温度に加熱し、プレス、押し出し等の手段により成形加工する方法である。上記キャスト法は、通常、含フッ素ポリマーをアルコール／水混合溶媒等の溶媒に溶解させてなる溶液を、ガラス等の基板に塗布し、乾燥させて得られる皮膜を基板から剥離する方法である。上記含浸法は、ガラス繊維、炭素繊維等の繊維状物質又はその織布、多孔性物質等の基材を、アルコール／水混合溶媒等の溶媒に含フッ素ポリマーを溶解してなる溶液に含浸し、乾燥させる方法である。
本発明の含フッ素成形体は、含フッ素ポリマーの優れた成形性を活かせる点で、上記溶融成形法を用いて成形してなるものであることが好ましい。
【００４６】
本発明の含フッ素成形体は、膜であることが好ましい。上記膜は、厚さが薄い部分に応力が集中し破れやすくなるので、厚さが均一又はほぼ均一であることが好ましい。上記膜の厚さとしては、１０〜２００μｍであることが好ましい。上記含フッ素成形体は、また、外観や風合いを向上する点で、平滑性を有するものであることが好ましい。
【００４７】
本発明の含フッ素成形体の用途としては特に限定されず、例えば、電解質膜、イオン交換膜等が挙げられる。上記含フッ素成形体は、電解質膜又はイオン交換膜として、例えば、電解質用膜、リチウム電池用膜、食塩電解用膜、水電解用膜、ハロゲン化水素酸電解用膜、酸素濃縮器用膜、湿度センサー用膜、ガスセンサー用膜等に用いることができ、使用条件が通常過酷な固体高分子電解質型燃料電池においても長期間好適に用いることができる。
【００４８】
上記含フッ素ポリマーからなる含フッ素成形体にアルカリ加水分解又は酸処理を行うことより得られる含フッ素成形体であって、金属塩を形成していてもよいスルホン酸基を有するものもまた、本発明の一つである。上記アルカリ加水分解に用いられるアルカリ、上記酸処理に用いられる酸、及び、上記金属塩を形成していてもよいスルホン酸基は、含フッ素ポリマー誘導体について上述したものと同様である。
【００４９】
【実施例】
以下に実施例を挙げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
実施例１
攪拌翼と温度調節用ジャケットのついた内容積３リットルのＳＵＳ−３１６製耐圧容器に、逆浸透膜水１５０１ｇ、Ｃ_７Ｆ_１５ＣＯＯＮＨ_４　７．５ｇ、パーフルオロ（エチルビニルエーテル）スルホン酸フルオライド（ＰＦＳＦ，ＣＦ_２＝ＣＦＯＣＦ_２ＣＦ_２ＳＯ_２Ｆ）６２．９ｇを仕込み、系内を窒素で置換した後、系内を真空とし、その後テトラフルオロエチレン〔ＴＦＥ〕を０．２ＭＰａまで導入した。系内温度が５０℃になるように温度調節を行い、内圧が０．８ＭＰａとなるようにさらにＴＦＥを導入した。（ＮＨ_４）_２Ｓ_２Ｏ_８　０．７５ｇを１０ｇの水に溶解させたものを系内に導入し、重合を開始した。系内の圧力を０．８ＭＰａに維持するようにＴＦＥを追加していき、追加したＴＦＥの量に合わせ、ＰＦＳＦとＴＦＥとのモル比が総仕込み量で０．４１８：１となるようにＰＦＳＦを追加で仕込んだ。重合開始から４７１分後、追加仕込みで投入したＴＦＥの総重量が４３７ｇとなった時点でＴＦＥを放圧し、重合を停止した。得られた重合液７０ｇに水１４０ｇを追加し、５０℃に加熱して濃塩酸７ｇを投入した。凝析したポリマーを濾過した後、水への再分散から塩酸による凝析濾過までの一連の操作を３回繰り返し、熱風乾燥器で乾燥し、含フッ素ポリマーを得た。ここで得られた含フッ素ポリマーを試料Ａとする。
【００５０】
得られた試料Ａを３００℃で^１９Ｆ−ＮＭＲの測定を行ったところ、−８０ｐｐｍ付近の−ＯＣＦ _２ＣＦ_２−の下線部のフッ素原子に帰属される強度と−１２５ｐｐｍ付近の主鎖炭素に結合するフッ素原子に帰属される強度との比から、ＰＦＳＦは１３ｍｏｌ％導入されたことがわかった。
得られた試料Ａを２７０℃にて熱圧してシート状に成形し、平行円盤型回転レオメータ（レオメトリックス社製、ＲＤＳ−ＩＩ型）を用い２７０℃にて溶融動的粘弾性の周波数分散を測定した。
【００５１】
実施例２
耐圧容器に仕込む物質の配合量及び重合条件を表１のように変えた以外は、実施例１と同様の手順により試料Ｂを得て、実施例１と同様の評価を行った。
【００５２】
比較例１
攪拌翼と温度調節用ジャケットのついた内容積３リットルのＳＵＳ−３１６製耐圧容器に、逆浸透膜水１４９０ｇ、Ｃ_７Ｆ_１５ＣＯＯＮＨ_４　３０ｇ、Ｎａ_２ＨＰＯ_４　６．２５ｇ、ＮａＨ_２ＰＯ_４　３．９４ｇ、ＰＦＳＦ　３００ｇを仕込み、系内を窒素で置換した後、系内を真空とし、その後ＴＦＥを０．２ＭＰａまで導入した。系内温度が５０℃になるように温度調節を行い、内圧が０．８ＭＰａとなるようにさらにＴＦＥを導入した。（ＮＨ_４）_２Ｓ_２Ｏ_８　３ｇを１０ｇの水に溶解させたものを系内に導入し、重合を開始した。系内の圧力を０．８ＭＰａに維持するようにＴＦＥのみを追加した。重合開始から１５１分後、追加で投入したＴＦＥの総重量が合計５２２ｇとなった時点でＴＦＥを放圧し、重合を停止した。得られた重合液７０ｇに水１４０ｇを追加し、５０℃に加熱して濃塩酸７ｇを投入した。凝析したポリマーを濾過した後、水への再分散から塩酸による凝析濾過までの一連の操作を３回繰り返し、熱風乾燥器で乾燥し、含フッ素ポリマーを得た。ここで得られた含フッ素ポリマーを試料Ｃとする。
【００５３】
得られた試料Ｃを３００℃で^１９Ｆ−ＮＭＲの測定を行ったところ、−８０ｐｐｍ付近の−ＯＣＦ _２ＣＦ_２−の下線部のフッ素原子に帰属される強度と−１２５ｐｐｍ付近の含フッ素ポリマーの主鎖炭素に結合するフッ素原子に帰属される強度との比から、ＰＦＳＦは１５．６ｍｏｌ％導入されたことがわかった。
得られた試料Ｃを厚さ１．５ｍｍのシートに成形し、平行円盤型回転レオメータ（レオメトリックス社製、ＲＤＳ−ＩＩ型）を用い２７０℃にて溶融動的粘弾性の周波数分散を測定した。
【００５４】
比較例２
耐圧容器に仕込む物質の配合量及び重合条件を表１のように変えた以外は、実施例１と同様の手順により試料Ｄを得て、実施例１と同様の評価を行った。
【００５５】
各実施例のマスバランス、重合条件、及び、得られた試料Ａ〜Ｄのキャラクタリゼーションを表１に表し、溶融動的粘弾性測定の結果を図１に表す。
【００５６】
【表１】

【００５７】
表１及び図１から、０．１〜１ｒａｄ／秒におけるｔａｎδが２以上の条件を満たす実施例は、いずれも０．１ｒａｄ／秒において５０００Ｐａ・ｓ以上の溶融粘度を有しながら、得られた膜の表面状態が良好であることがわかった。
【００５８】
【発明の効果】
本発明の含フッ素ポリマーは、上述の構成よりなるので、高い溶融粘度と優れた成形性を有し、滑らかな表面を有する含フッ素成形体を得ることができる。
【図面の簡単な説明】
【図１】図１は、実施例１〜２及び比較例１〜２の各試料についてｔａｎδの周波数分散を測定し得られたチャートである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluoropolymer, a fluoropolymer production method, a fluoropolymer derivative, and a fluoropolymer.
[0002]
[Prior art]
A fluorine-containing vinyl ether having a halosulfonyl group at a terminal is used as it is or after protecting the halosulfonyl group by esterification or imidation, and then polymerized with other olefins such as fluoroolefins to obtain a copolymer. Can be.
[0003]
The resulting copolymer, after converting a halosulfonyl group into a sulfonic acid group having a salt-forming property, may be used as an ion exchange membrane or an electrolyte membrane of a salt electrolysis, a chemical sensor, a separation membrane, a fuel cell, or the like, In addition, the powder can be used as a polymer superacid catalyst as it is, or can be used for a lithium battery or the like.
[0004]
When the obtained copolymer is used in the form of a film, examples of the film forming method include a melt molding method and a solvent casting method. Among them, the melt molding method is generally used as a film forming method, but has a problem that it is restricted by the melt properties of the copolymer.
[0005]
Japanese Patent Application Laid-Open No. 4-366137 discloses that when a melt molding method is used, those having a melt viscosity of 600 to 8000 Pa · s (ASTM D 3835) at 250 ° C. are preferable for film forming. However, in fact, the region where the melt viscosity is larger than 5200 Pa · s is unknown.
[0006]
Japanese Patent No. 2675548 discloses that if the melt viscosity at the molding temperature is too high, it is difficult to handle the film and the film cannot be formed, and it is 149 ° C., at a shear rate of 100 / sec, less than 1600 Pa · s, and at a shear rate of 10 / sec. There is a statement that it is required to have a melt viscosity of less than 7,500 Pa · s.
[0007]
As described above, in the melt molding method, it has conventionally been considered important to keep the melt viscosity low from the viewpoint of film formation. On the other hand, membranes have been required to have improved mechanical strength in applications and the like used in the presence of water. In order to improve the mechanical strength, it is inevitable to increase the molecular weight, and the melt viscosity must be increased.
[0008]
However, if the melt viscosity at the film forming temperature is too high or insufficiently melted, the film shrinks during or after film formation, and a groove-shaped unevenness or citron skin parallel to the extrusion direction is generated on the film surface. was there. Therefore, it has been required to form a film having a smooth surface without unevenness using a fluoropolymer having a high melt viscosity.
[0009]
The fluorine-containing polymer is a viscoelastic body like other polymer substances. Japanese Patent No. 2675548 describes each of viscosity and elasticity, but does not describe a relationship to be satisfied between the two.
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances and provides a fluorine-containing polymer having a high melt viscosity and excellent moldability, and a fluorine-containing molded body having a smooth surface.
[0011]
[Means for Solving the Problems]
The present invention relates to the following general formula (I)
[0012]
Embedded image

[0013]
(In the formula, Y ¹ represents a halogen atom or a perfluoroalkyl group. Y ² represents a halogen atom. N represents an integer of 0 to ^{3. Even if} n Y ¹ are the same, good it may be different .m is .m number of ^{Y 2} representing an integer of 1 to 5 are optionally different may be the same .A ¹ is _-SO 2 ^{X 1} or - Represents COY ^3. X ¹ represents a halogen atom, —OM ¹ , —OM ² _1/2 or —NR ¹ R ² , and M ¹ represents a hydrogen atom, NR ³ R ⁴ R ⁵ R ⁶ or an alkali metal. And M ² represents an alkaline earth metal, R ¹ and R ² are the same or different and represent a hydrogen atom, an alkali metal, a sulfonyl-containing group or an alkyl group, and R ³ , R ⁴ , R ⁵ and R ⁶ is the same or different and represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y ³ represents a hydroxyl group, —NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms, wherein R ⁷ and R ⁸ are the same or different and each represent a hydrogen atom, an alkali metal, an alkyl group, or a sulfonyl-containing group; Fluorine-containing polymer obtained by polymerizing a perfluorovinyl ether derivative represented by the following formula: 270 ° C., and a melt dynamic viscoelasticity measurement under a measurement condition of strain of 0.1 to 30%. a) a fluoropolymer satisfying the following condition (b):
(A) The melt viscosity at 0.1 rad / sec is 5000 Pa · s or more.
(B) Tan δ at 0.1 to 1 rad / sec is 2 to 50.
[0014]
The present invention is a method for producing a fluoropolymer, which comprises producing the above fluoropolymer, wherein the polymerization reaction is carried out while additionally adding the perfluorovinyl ether derivative represented by the above general formula (I). Is a method for producing a fluoropolymer.
[0015]
The present invention is a fluoropolymer derivative obtained by subjecting the above-mentioned fluoropolymer to alkali hydrolysis or acid treatment, and having a sulfonic acid group which may form a metal salt. .
[0016]
The present invention is a fluorinated molded article comprising the fluorinated polymer and / or the fluorinated polymer derivative.
The present invention is a fluorinated molded article obtained by performing alkali hydrolysis or acid treatment on a molded article molded using the above-mentioned fluoropolymer, which has a sulfonic acid group which may form a metal salt. It is a fluorine-containing molded article characterized in that:
Hereinafter, the present invention will be described in detail.
[0017]
The fluoropolymer of the present invention has a tan δ at 0.1 to 1 rad / sec of 2 or more in a melt dynamic viscoelasticity measurement at 270 ° C.
[0018]
The tan δ is an index of the relative balance between viscosity and elasticity. If the value of tan δ is large, the balance between viscosity and elasticity shifts to the viscous side, and there is a strong tendency to maintain the deformation generated when a force is applied, resulting in good moldability. When the value of tan δ is small, the balance between viscosity and elasticity shifts to the elastic side, and after molding, elastic contraction tends to occur when cooling, and the tendency to return to the state before applying force is strong. Become. If the tan δ is extremely small, irregularities are likely to occur on the surface of the obtained molded body. In the present invention, it has been found that this tendency is particularly strong when tan δ is less than 2.0. A preferred lower limit is 2.2. tan δ is not particularly limited as long as it is within the above range, and may be, for example, 50 or less.
[0019]
The above-mentioned fluoropolymer has a melt viscosity at a molding temperature of 0.1 rad / sec of 5000 Pa · s or more. If it is less than 5000 Pa · s, the mechanical strength of the obtained molded article will be reduced. A preferred lower limit is 10,000 Pa · s, a more preferred lower limit is 20,000 Pa · s, and a still more preferred lower limit is 30,000 Pa · s. The melt viscosity is not particularly limited as long as it is within the above range. However, from the viewpoint of maintaining the moldability, the melt viscosity can be, for example, 100000 Pa · s or less.
[0020]
When the melt viscosity is large, the molecular weight is generally high. When the molecular weight is high, generally, the mechanical strength of the obtained molded article can be improved.
The molecular weight is related to the melt flow rate [MFR].
The MFR is a flow rate of a melt of the fluoropolymer extruded from a cylinder having a specified diameter and length under a constant temperature and a constant load, and is a value obtained by measuring in accordance with ASTM D 3159. It is. Generally, the higher the MFR, the lower the molecular weight.
The above MFR is preferably 10 g / 10 min or less in order for the obtained fluoropolymer to have sufficient mechanical strength. A more preferred upper limit is 6 g / 10 minutes.
[0021]
It has been considered that, when the melt viscosity is large, the polymer chain is generally long as described above, and the moldability is conventionally deteriorated. However, the present invention has revealed that, even if the melt viscosity is high, if the above-mentioned tan δ condition is satisfied, the above-mentioned fluoropolymer is excellent in moldability and can obtain a fluorine-containing molded article having a smooth surface. Things. Therefore, the fluorine-containing polymer of the present invention can achieve both moldability and mechanical strength of the obtained fluorine-containing molded article.
[0022]
The tan δ and the melt viscosity are values obtained by melt dynamic viscoelasticity measurement. The melt dynamic viscoelasticity measurement is a measurement method in which a strain whose magnitude changes in a sine cycle is applied to the fluoropolymer, and the response of mechanical stress to the strain is examined. The allowable range of the strain is generally a range in which the object to be measured exhibits linear viscoelasticity. When the measurement object is the fluoropolymer, the strain is in the range of 0.1 to 30%.
In this specification, the change cycle of the distortion may be referred to as “frequency”. The above numerical values of “0.1 to 1 rad / sec” and “0.1 rad / sec” are frequencies.
[0023]
The fluoropolymer is obtained by polymerizing at least the perfluorovinyl ether derivative represented by the general formula (I).
[0024]
N in the general formula (I) represents an integer of 0 to 3. The above n is preferably 0 or 1, and more preferably 0. M in the general formula (I) represents an integer of 1 to 5. Preferably, it is 2.
[0025]
Y ¹ in the general formula (I) represents a halogen atom or a perfluoroalkyl group. The n pieces of Y ¹ may be the same or different. Y ² represents a halogen atom. m atoms of Y ² may be the same or may be different. The halogen atom of Y ¹ and Y ² is not particularly limited, and may be any of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and is preferably a fluorine atom. The perfluoroalkyl group is not particularly limited, and includes, for example, a trifluoromethyl group, a pentafluoroethyl group and the like. Preferably, Y ¹ is a trifluoromethyl group and Y ² is a fluorine atom.
[0026]
A in the general formula (I) represents the _-SO 2 ^{X 1} or -COY ^3.
The ^{X 1} represents a halogen _{^{atom, -OM 1, -OM 2 1/}} 2 or ^-NR 1 ^{R 2.} M ¹ represents a hydrogen atom, NR ³ R ⁴ R ⁵ R ⁶ or an alkali metal; R ¹ and R ² are the same or different and represent a hydrogen atom, an alkali metal, a sulfonyl-containing group or an alkyl group; ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The M ² represents an alkaline earth metal. The sulfonyl-containing group is a fluorinated alkyl group having a sulfonyl group, and examples thereof include a fluorinated alkylsulfonyl group which may have a substituent at the terminal. Examples of such a group include -SO ₂ R _f ⁴ Z (R _f ⁴ represents a fluorine-containing alkylene group, and Z represents a monovalent organic group) and the like. As the Z, for ^{_{example, -SO 2 F, -SO 2 (}} NHSO 2 R f 4 SO 2) k NHSO 2 F (R f 4 are as defined above .k represents. An integer of 1 or more) and the like No.
[0027]
The halogen atom of the X ^1, although the same can be listed as the Y ¹ and the Y ^2, the X ^1, the Y ¹ and the Y ² may be the same or may be different . The alkali metal is not particularly limited, and includes, for example, Li, Na, K, Cs and the like. The alkaline earth metal is not particularly limited, and includes, for example, Mg, Ca and the like. The alkyl group is not particularly limited, and includes, for example, a methyl group, an ethyl group, and the like. Preferably, X ¹ is a fluorine atom. Y ³ represents a hydroxyl group, —NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms. Examples of the above R ⁷ and R ⁸ include the same as those of the above R ¹ and R ^2, and the above R ¹ , R ² , R ⁷ and R ⁸ may be the same or different. .
[0028]
In the fluoropolymer of the present invention, Y ¹ in the above general formula (I) is a trifluoromethyl group, Y ² is a fluorine atom, n is 0 or 1, m is 2, and X ¹ is It is preferably a fluorine atom.
[0029]
The fluoropolymer is preferably a binary or higher copolymer obtained by polymerizing the perfluorovinyl ether derivative and an ethylenic monomer.
[0030]
The above-mentioned ethylenic monomer is a polymerizable with the above-mentioned perfluorovinyl ether derivative and has no ionizable functional group capable of being ionized. The ionizing functional group is not particularly limited, and examples thereof include a sulfonic acid group, a carboxyl group, a sulfonic acid group forming a salt, and a carboxyl group forming a salt. The above “forming a salt” is one in which an atom or an atomic group capable of forming a monovalent or divalent cation is bonded instead of a hydrogen atom.
[0031]
Further, the sulfonic acid group forming the salt and the carboxyl group forming the salt may be ionized in a liquid solvent, particularly in a liquid solvent containing water or a water-soluble solvent. The atom or atomic group capable of forming the monovalent or divalent cation is not particularly limited, and includes, for example, the above-mentioned alkali metals; the above-mentioned alkaline earth metals; and ammonium ions. These may be the same or different in one molecule of the fluoropolymer and / or between a plurality of molecules of the fluoropolymer.
[0032]
The above-mentioned ethylenic monomer is not particularly limited. For example, the following general formula CF ₂ ＣＦCF-R _f ¹
(In the formula, R _f ¹ represents a fluorine atom, a chlorine atom, R _f ² or OR _f ² , and R _f ² is a linear or branched group which may have an ether oxygen having 1 to 9 carbon atoms. A perfluoroethylenic monomer represented by the following formula: CHX ¹ CFX ²
(Wherein, X ¹ represents a hydrogen atom or a fluorine atom, X ² represents a hydrogen atom, a fluorine atom, a chlorine atom, R _f ³ or OR _f ^3. R _f ³ has 1 to 9 carbon atoms. Represents a linear or branched perfluoroalkyl group which may have an ether oxygen).
[0033]
Ethylenic monomer is preferably a perhalo ethylenic monomer, the ethylene _{monomer, CF 2 = CF 2, CF} 2 = CFCF 3, CF 2 = CF-OCF 3, CF 2 = CF- OCF ₂ CF ₃ and _CF 2 = more preferably _CF-OCF selected from 2 _CF 2 group consisting of CF ₃ is at least one.
More preferably, the ethylenic monomer satisfies CF ₂ = CF ₂ .
[0034]
In addition to the ethylenic monomer, other copolymerizable monomers may be added to impart various functions to the fluorine-containing polymer, as long as the basic performance as a polymer electrolyte is not impaired. . The above-mentioned other copolymerizable monomers are not particularly limited, and may be copolymerized according to purposes such as control of polymerization rate, control of polymer composition, control of mechanical properties such as elastic modulus, introduction of a crosslinking site, and the like. And a monomer having two or more unsaturated bonds, such as divinylbenzene, a monomer having a cyano group, a monomer having a halogen atom at a terminal, and the like.
[0035]
The method for producing a fluoropolymer of the present invention comprises producing the above fluoropolymer, and comprises conducting a polymerization reaction while additionally adding a perfluorovinyl ether derivative represented by the above general formula (I). It is a feature.
[0036]
In the present specification, the `` additional charge '' does not mean that the entire amount of the perfluorovinyl ether derivative used in the polymerization reaction is present in the reaction system at the start of the polymerization, but at least a part of the added amount after the start of the polymerization. It means that the reaction system is charged intermittently or continuously. By performing the additional charging, the tan δ and the melt viscosity can be set in the above ranges, and as a result, moldability can be improved.
[0037]
It is preferable that the additional charging be performed also on the above-mentioned ethylenic monomer. When both the ethylenic monomer (a) and the perfluorovinyl ether derivative (b) are additionally charged, it is preferable to perform the additional charging so as to keep the molar concentration ratio in the reaction system constant. The molar concentration ratio in the above reaction system is determined in consideration of the copolymerizability ratio, the use of the obtained fluoropolymer, and the like, but (a) :( b) is usually in the range of 1: 1 to 9: 1. It is preferable that
[0038]
The method of the polymerization reaction is not particularly limited, and for example, conventionally known polymerization methods such as suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization can be used. , Suspension polymerization or emulsion polymerization is preferred, and emulsion polymerization is more preferred.
Conventionally known types and concentrations, polymerization temperatures, and polymerization pressures of the polymerization initiator used in the polymerization reaction can be used.
[0039]
The fluoropolymer derivative of the present invention is obtained by subjecting the above-mentioned fluoropolymer to alkali hydrolysis or acid treatment, and has a sulfonic acid group which may form a metal salt. Things. At this time, it can be said that the fluoropolymer is a precursor of the fluoropolymer derivative.
The sulfonic acid group forming the metal salt has the same concept as the sulfonic acid group forming the above-described salt except that the salt is limited to the metal salt.
[0040]
The fluoropolymer derivative is not particularly limited, and may be, for example, the following general formula (II)
[0041]
Embedded image

[0042]
(Y ^{1, Y} 2, ⁿ and m .n-number of Y ¹ are as described above may be different may be the same, m-number of Y ² may be the same A ² represents —SO ₂ X ² or —COY ^4. X ² represents a halogen atom or —NR ¹ R ^2. R ¹ and R ² are the same or different, and A hydrogen atom, an alkali metal, a sulfonyl-containing group or an alkyl group, Y ⁴ represents —NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms, and R ⁷ and R ⁸ are the same or different and are each a hydrogen atom , an alkali metal, in an alkyl group or a sulfonyl-containing group.) in perfluorovinyl ether derivative (T1) polymerization to obtained fluorine-containing polymer represented (T), the alkali hydrolysis of the X ² or the Y ⁴ Performing disassembly To -OM ³ or -OM ⁴ _1/2 (wherein, M ³ represents a hydrogen atom or an alkali metal, and M ⁴ represents an alkaline earth metal). It may be.
[0043]
Examples of the halogen atom for X ² include the same as those for Y ¹ and Y ² above, and preferably a fluorine atom. The alkoxyl group for Y ⁴ is preferably —OCH ₃ . As the ^{A _2,} -SO ² _F, it is -COOCH ₃ preferred.
The M ³ and the M ⁴ are those derived from the alkali used in the alkaline hydrolysis. The ^{M 3} represents the ^{M 1} described above, the ^{M 4} and ^{M 2} described above, the same each include, ^{M 1} described above and the ^{M 3, M 2} described above and the ^{M 4} are respectively the same May be present or different.
The alkali is not particularly limited, and includes, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like.
[0044]
The fluorine-containing polymer derivatives performs acid treatment the fluoropolymer derivative (U), the -OM ³ or ^-OM _{4 1/2} above or may be converted to -OH. The acid used for the acid treatment is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; and organic acids such as formic acid, acetic acid, and propionic acid.
[0045]
The present invention also provides a fluorinated molded article comprising the above fluorinated polymer or the above fluorinated polymer derivative.
The method for molding the above-mentioned fluorinated molded article is not particularly limited, and examples thereof include a melt molding method, a casting method, and an impregnation method. The melt molding method is a method in which a fluorine-containing polymer is heated to a temperature equal to or higher than the melting point and molded by means such as pressing or extrusion. The casting method is a method in which a solution obtained by dissolving a fluorine-containing polymer in a solvent such as an alcohol / water mixed solvent is usually applied to a substrate such as glass and dried to peel off a film obtained from the substrate. In the above impregnation method, a fibrous material such as glass fiber or carbon fiber or a woven fabric thereof, a substrate such as a porous material, or the like is impregnated with a solution obtained by dissolving a fluoropolymer in a solvent such as an alcohol / water mixed solvent. , Drying method.
It is preferable that the fluorinated molded article of the present invention is formed using the above-mentioned melt molding method from the viewpoint that the excellent moldability of the fluorinated polymer can be utilized.
[0046]
The fluorine-containing molded article of the present invention is preferably a membrane. It is preferable that the thickness of the film is uniform or almost uniform because stress concentrates on a thin portion and the film is easily broken. The thickness of the film is preferably from 10 to 200 μm. It is preferable that the above-mentioned fluorine-containing molded article has smoothness from the viewpoint of improving appearance and feel.
[0047]
The application of the fluorine-containing molded article of the present invention is not particularly limited, and examples thereof include an electrolyte membrane and an ion exchange membrane. The above-mentioned fluorine-containing molded article may be used as an electrolyte membrane or an ion exchange membrane, for example, an electrolyte membrane, a lithium battery membrane, a salt electrolysis membrane, a water electrolysis membrane, a hydrohalic acid electrolysis membrane, an oxygen concentrator membrane, a humidity It can be used as a membrane for sensors, a membrane for gas sensors, and the like, and can be suitably used for a long period of time even in a solid polymer electrolyte fuel cell where use conditions are usually severe.
[0048]
Fluorine-containing molded articles obtained by subjecting a fluorinated molded article made of the above-mentioned fluoropolymer to alkali hydrolysis or acid treatment and having a sulfonic acid group which may form a metal salt are also described in the present invention. This is one of the inventions. The alkali used for the alkali hydrolysis, the acid used for the acid treatment, and the sulfonic acid group which may form the metal salt are the same as those described above for the fluoropolymer derivative.
[0049]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
Example 1
In a 3 liter SUS-316 pressure vessel equipped with a stirring blade and a temperature control jacket, 1501 g of reverse osmosis membrane water, 7.5 g of C ₇ F ₁₅ COONH ₄ , and perfluoro (ethyl vinyl ether) sulfonic acid fluoride (PFSF) , CF ₂ = CFOCF ₂ CF ₂ SO ₂ F) was charged, and the inside of the system was replaced with nitrogen. Then, the inside of the system was evacuated, and then tetrafluoroethylene [TFE] was introduced up to 0.2 MPa. The temperature was adjusted so that the temperature in the system became 50 ° C., and TFE was further introduced so that the internal pressure became 0.8 MPa. A solution obtained by dissolving 0.75 g of (NH ₄ ) ₂ S ₂ O ₈ in 10 g of water was introduced into the system, and polymerization was started. TFE was added so as to maintain the pressure in the system at 0.8 MPa, and PFSF was added so that the molar ratio between PFSF and TFE was 0.418: 1 in total charge according to the amount of TFE added. Was additionally charged. 471 minutes after the start of the polymerization, when the total weight of the TFE charged by the additional charge reached 437 g, the TFE was released to stop the polymerization. 140 g of water was added to 70 g of the obtained polymerization solution, and the mixture was heated to 50 ° C., and 7 g of concentrated hydrochloric acid was added. After filtering the coagulated polymer, a series of operations from re-dispersion in water to coagulation filtration with hydrochloric acid was repeated three times, followed by drying with a hot air drier to obtain a fluoropolymer. The fluoropolymer obtained here is designated as Sample A.
[0050]
The obtained A sample A was measured ¹⁹ F-NMR at 300 ℃, -OC _{F 2} CF 2 near -80 ppm - main chain carbon near strength and -125ppm attributed to fluorine atom underlined in It was found that PFSF was introduced in an amount of 13 mol% from the ratio to the intensity attributable to the fluorine atom bonded to.
The obtained sample A was hot-pressed at 270 ° C. to form a sheet, and the dynamic dispersion of the dynamic viscoelasticity at 270 ° C. was measured at 270 ° C. using a parallel disk-type rotary rheometer (RDS-II, manufactured by Rheometrics). It was measured.
[0051]
Example 2
Sample B was obtained in the same procedure as in Example 1 except that the compounding amount of the substance charged in the pressure vessel and the polymerization conditions were changed as shown in Table 1, and the same evaluation as in Example 1 was performed.
[0052]
Comparative Example 1
1490 g of reverse osmosis membrane water, 30 g of C ₇ F ₁₅ COONH ₄ , 6.25 g of Na ₂ HPO _{4, and} 6.25 g of NaH ₂ PO ₄ 3 were placed in a 3 liter pressure vessel made of SUS-316 equipped with a stirring blade and a jacket for temperature control. After charging 0.94 g and 300 g of PFSF and replacing the inside of the system with nitrogen, the inside of the system was evacuated, and then TFE was introduced to 0.2 MPa. The temperature was adjusted so that the temperature in the system became 50 ° C., and TFE was further introduced so that the internal pressure became 0.8 MPa. A solution in which 3 g of (NH ₄ ) ₂ S ₂ O ₈ was dissolved in 10 g of water was introduced into the system, and polymerization was started. Only TFE was added so as to maintain the pressure in the system at 0.8 MPa. 151 minutes after the start of the polymerization, when the total weight of the additionally charged TFE reached 522 g in total, the TFE was released and the polymerization was stopped. 140 g of water was added to 70 g of the obtained polymerization solution, and the mixture was heated to 50 ° C., and 7 g of concentrated hydrochloric acid was added. After filtering the coagulated polymer, a series of operations from re-dispersion in water to coagulation filtration with hydrochloric acid was repeated three times, followed by drying with a hot air drier to obtain a fluoropolymer. The fluorine-containing polymer obtained here is used as sample C.
[0053]
The resulting sample C was measured for the ¹⁹ F-NMR at 300 ℃, -OC _{F 2} CF 2 near -80 ppm - fluoropolymer near strength and -125ppm attributed to fluorine atom underlined in From the ratio to the intensity attributed to the fluorine atom bonded to the main chain carbon, it was found that 15.6 mol% of PFSF was introduced.
The obtained sample C was formed into a sheet having a thickness of 1.5 mm, and the frequency dispersion of the melt dynamic viscoelasticity was measured at 270 ° C. using a parallel disk type rotational rheometer (RDS-II, manufactured by Rheometrics). .
[0054]
Comparative Example 2
A sample D was obtained in the same procedure as in Example 1 except that the amount of the substance charged in the pressure-resistant container and the polymerization conditions were changed as shown in Table 1, and the same evaluation as in Example 1 was performed.
[0055]
Table 1 shows the mass balance, polymerization conditions, and characterization of the obtained samples A to D in each example, and FIG. 1 shows the results of melt dynamic viscoelasticity measurement.
[0056]
[Table 1]

[0057]
From Table 1 and FIG. 1, the examples satisfying the condition that tan δ at 0.1 to 1 rad / sec is 2 or more were obtained while having a melt viscosity of 5000 Pa · s or more at 0.1 rad / sec. The surface condition of the film was found to be good.
[0058]
【The invention's effect】
Since the fluoropolymer of the present invention has the above-described constitution, it has a high melt viscosity and excellent moldability, and can obtain a fluorinated molded article having a smooth surface.
[Brief description of the drawings]
FIG. 1 is a chart obtained by measuring the frequency dispersion of tan δ for each sample of Examples 1 and 2 and Comparative Examples 1 and 2.

Claims (13)

The following general formula (I)

(In the formula, Y ¹ represents a halogen atom or a perfluoroalkyl group. Y ² represents a halogen atom. N represents an integer of 0 to ^{3. Even if} n Y ¹ are the same, good it may be different .m is .m number of ^{Y 2} representing an integer of 1 to 5 are optionally different may be the same .A ¹ is _-SO 2 ^{X 1} or - Represents COY ^3. X ¹ represents a halogen atom, —OM ¹ , —OM ² _1/2 or —NR ¹ R ² , and M ¹ represents a hydrogen atom, NR ³ R ⁴ R ⁵ R ⁶ or an alkali metal. And M ² represents an alkaline earth metal, R ¹ and R ² are the same or different and represent a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group, and R ³ , R ⁴ , R ⁵ and R ⁶ is the same or different and represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y ³ represents a hydroxyl group, —NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms, wherein R ⁷ and R ⁸ are the same or different and each represent a hydrogen atom, an alkali metal, an alkyl group, or a sulfonyl-containing group; Which is a fluorine-containing polymer obtained by polymerizing a perfluorovinyl ether derivative represented by the formula:
A fluorine-containing polymer, which satisfies the following conditions (a) and (b) in melt dynamic viscoelasticity measurement under measurement conditions of 270 ° C. and strain of 0.1 to 30%.
(A) The melt viscosity at 0.1 rad / sec is 5000 Pa · s or more.
(B) Tan δ at 0.1 to 1 rad / sec is 2 to 50. A copolymer of two or more obtained by polymerizing a perfluorovinyl ether derivative and an ethylenic monomer,
The ethylenic monomer _is a group consisting of _{CF 2 = CF 2, CF 2} = CFCF 3, CF 2 = CF-OCF 3, CF 2 = CF-OCF 2 CF 3 and _{CF 2 = CF-OCF 2 CF} 2 CF 3 The fluoropolymer according to claim 1, which is at least one member selected from the group consisting of: ^{3. The method according to} claim ¹ , wherein Y ¹ is a trifluoromethyl group, Y ² is a fluorine atom, n is 0 or 1, m is 2, and X ¹ is a fluorine atom. 4. Fluoropolymer. 4. The fluoropolymer according to claim 1, wherein the melt viscosity is 10,000 Pa · s or more. The fluoropolymer according to claim 1, 2 or 3, wherein the melt viscosity is 20,000 Pa · s or more. The fluoropolymer according to claim 1, 2 or 3, wherein the melt viscosity is 30,000 Pa · s or more. A method for producing a fluoropolymer, comprising producing the fluoropolymer according to claim 1, 2, 3, 4, 5, or 6.
The following general formula (I)

(In the formula, Y ¹ represents a halogen atom or a perfluoroalkyl group. Y ² represents a halogen atom. N represents an integer of 0 to ^{3. Even if} n Y ¹ are the same, good it may be different .m is .m number of ^{Y 2} representing an integer of 1 to 5 are optionally different may be the same .A ¹ is _-SO 2 ^{X 1} or - Represents COY ^3. X ¹ represents a halogen atom, —OM ¹ , —OM ² _1/2 or —NR ¹ R ² , and M ¹ represents a hydrogen atom, NR ³ R ⁴ R ⁵ R ⁶ or an alkali metal. And M ² represents an alkaline earth metal, R ¹ and R ² are the same or different and represent a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group, and R ³ , R ⁴ , R ⁵ and R ⁶ is the same or different and represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y ³ represents a hydroxyl group, —NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms, wherein R ⁷ and R ⁸ are the same or different and each represent a hydrogen atom, an alkali metal, an alkyl group, or a sulfonyl-containing group; Wherein the polymerization reaction is carried out while additionally adding the perfluorovinyl ether derivative represented by the formula (1). It is obtained by subjecting the fluorine-containing polymer according to claim 1, 2, 3, 4, 5 or 6 to alkali hydrolysis or acid treatment,
A fluoropolymer derivative having a sulfonic acid group which may form a metal salt. The fluorine-containing polymer has the following general formula (II)

(In the formula, Y ¹ represents a halogen atom or a perfluoroalkyl group. Y ² represents a halogen atom. N represents an integer of 0 to ^{3. Even if} n Y ¹ are the same, good it may be different .m is .m number of ^{Y 2} representing an integer of 1 to 5 are good .A ² be different may be the same, _-SO 2 ^{X 2} or - .X ² representing the COY ⁴ is .R ¹ and ^{R 2} represents a halogen atom or ^-NR 1 ^{R 2} are the same or different, .Y ⁴ represents a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group , -NR ⁷ R ⁸ or an alkoxyl group having 1 to 4 carbon atoms, wherein R ⁷ and R ⁸ are the same or different and represent a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group. Perfluorovinylether derivative (T1) A and fluorine-containing polymer obtained by (T),
The fluorine-containing polymer derivative, -OM ³ or ^-OM _{4 1/2} (wherein in the ^{X 2} or the ^{Y 4} is the fluorine-containing polymer (T), ^{M 3} represents a hydrogen atom or an alkali metal, ^{M 4} Represents a alkaline earth metal.) The fluorine-containing polymer derivative according to claim 8, wherein A fluorine-containing molded article comprising the fluorine-containing polymer according to claim 1, 2, 3, 4, 5, or 6, and / or the fluorine-containing polymer derivative according to claim 8 or 9. A fluorinated molded article obtained by subjecting a molded article molded using the fluoropolymer according to claim 1, 2, 3, 4, 5, or 6 to alkali hydrolysis or acid treatment,
A fluorine-containing molded product having a sulfonic acid group which may form a metal salt. The fluorine-containing molded product according to claim 10 or 11, which is a film. A solid polymer electrolyte fuel cell comprising the fluorine-containing molded product according to claim 10.

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