JP3663060B2 - Polyimide film - Google Patents

Description

【００１０】
（式中Ｙは、Ｈ、メチル基又はハロゲン基を表し、Ｒ₁はＨ、炭素数１８以下のアルキル基又はフェニル基を表し、ａは１以上の整数を表す。）で表される。エチレングリコ−ル鎖の末端は水酸基、アルキルまたはフェニル基でもよいが、水酸基の水素がアルキルまたはフェニル基で置換されているものが好ましい。ポリアミド酸は水やアルコ−ル類等の水酸基を有する化合物により加水分解反応を起こしポリアミド酸の保存安定性を損なうからである。
【００１１】
エチレングリコ−ル鎖を有する有機オニウムイオンとしてはＰＥＧアンモニウム（以下ＰＥＧは一般式（１）中のＹが水素であるエチレングリコ−ル鎖を表す。）のような１級アンモニウムイオン、メチルＰＥＧアンモニウム、ドデシルＰＥＧアンモニウム等の２級アンモニウムイオン、ジメチルＰＥＧアンモニウム、メチルドデシルＰＥＧアンモニウム等の３級アンモニウムイオン、４級アンモニウムイオンとしてジメチルビスＰＥＧアンモニウム、ジエチルビスＰＥＧアンモニウム、ジブチルビスＰＥＧアンモニウム、メチルエチルビスＰＥＧアンモニウム等のジアルキルビスＰＥＧアンモニウムイオンやジメチルビスＰＥＧホスホニウム、ジエチルビスＰＥＧホスホニウム、ジブチルビスＰＥＧホスホニウム、メチルエチルビスＰＥＧホスホニウム等のジアルキルビスＰＥＧホスホニウムイオン、メチルトリスＰＥＧアンモニウム、エチルトリスＰＥＧアンモニウム、ブチルトリスＰＥＧアンモニウム等のアルキルトリスＰＥＧアンモニウムイオン、メチルトリスＰＥＧホスホニウム、エチルトリスＰＥＧホスホニウム、ブチルトリスＰＥＧホスホニウム等のアルキルトリスＰＥＧホスホニウムイオンが挙げられる。
【００１２】
これらのうち、ポリイミドとの親和性、耐熱性、入手容易性からジメチルビスＰＥＧアンモニウム、メチルドデシルビスＰＥＧアンモニウム等のジアルキルビスＰＥＧアンモニウムイオンやジメチルビスＰＥＧホスホニウム、メチルドデシルビスＰＥＧホスホニウム等のジアルキルビスＰＥＧホスホニウムイオンが好ましい。特にポリイミド樹脂マトリックス中で層間化合物が凝集しにくいという点で４級オニウムイオンが好適である。
【００１３】
本発明で用いる層間化合物は、層状珪酸塩にエチレングリコ−ル鎖を有する有機オニウムイオンを作用させて得られる。層状珪酸塩は、モンモリロナイト、ヘクトライト、フッ素ヘクトライト、サポナイト、バイデライト、スチブンサイト等のスメクタイト系粘土鉱物類、Ｌｉ型フッ素テニオライト、Ｎａ型フッ素テニオライト、Ｎａ型四珪素フッ素雲母、Ｌｉ型四珪素フッ素雲母等の膨潤性合成雲母、バ−ミキュライト、フッ素バ−ミキュライト、ハロイサイト等が挙げられ天然のものでも合成されたものでも良く、またこれらを１種または２種以上混合して用いることもできる。層状珪酸塩は、一部劈開された層状珪酸塩の他、単位構造にまで劈開されたものも含む。層状珪酸塩の単位構造は、Ａｌ、Ｍｇ、Ｌｉ、Ｎａ等を含む八面体シ−ト構造を２枚のＳｉＯ₄四面体シ−ト構造が挟んだ形の２：１型が好適であり、その単位構造である１層の厚みは通常１ｎｍ程度である。
【００１４】
層状珪酸塩の陽イオン交換容量（ＣＥＣ）は、４０〜３００ミリ当量／１００ｇの範囲が好ましく、５０〜２００ミリ当量／１００ｇの範囲がより好ましい。ＣＥＣが４０ミリ当量／１００ｇ未満では、層間への有機オニウムイオンの挿入量が不十分となり、ポリイミド樹脂との親和性が低下しポリイミド樹脂中への分散性が悪化する。逆にＣＥＣが３００ミリ当量／１００ｇより大きいと、層状珪酸塩の層間結合力が強すぎるため層状珪酸塩の層間拡張が困難となり、ポリイミド樹脂への分散性が悪くなる。分散性が悪いと組成物の強度や靭性等の特性向上が充分でなく、かつ成形表面外観も著しく損なうことになる。
【００１５】
本発明に用いられる層間化合物とは、モンモリロナイトやスメクタイト等の層状珪酸塩の層間にエチレングリコ−ル鎖を有する有機オニウムイオンが挿入された化合物である。このような層間化合物は、有機オニウムイオンを、負の層格子及び交換可能なカチオンを含有する層状粘土鉱物と反応させる公知の技術（例えば特公昭６１−５４９２号公報、特開昭６０−４２４５１号公報、特願平６−２３１７４８号（特開平８−１２８８１号）、特願平６−２３１７４６号（特開平７−１６６０３６号）等）により製造される。
【００１６】
ポリイミド樹脂は、テトラカルボン酸二無水物とジアミンとの縮合反応により得られるポリアミド酸を脱水反応を行うことによって得られるポリイミド樹脂である。テトラカルボン酸二無水物としては、ピロメリット酸、３，３'、４，４'−ベンゾフェノンテトラカルボン酸二無水物、３，３'、４，４'−ジフェニルエ−テルテトラカルボン酸二無水物、３，３'、４，４'−ジフェニルテトラカルボン酸二無水物、１，４−ヒドロキノンジベンゾエ−ト−３，３'，４，４'−テトラカルボン酸二無水物挙げられ、１種または2種以上混合して用いることもできる。
【００１７】
またジアミン類としては、パラフェニレンジアミン、４，４'−ジアミノジフェニルエ−テル、４，４'−ジアミノベンズアニリド、２、２−ビス[（４−アミノフェノキシ）フェニル]プロパンが挙げられ、１種または２種以上混合して用いることもできる。本発明のポリイミド系フィルムの製造方法を説明する。
【００１８】
ポリイミド前駆体である一般式
【００１９】
【化５】

【００２０】
（式中Ｒ₆は４価の有機基、Ｒ₇は２価の有機基を示す。）で表されるポリアミド酸と層間化合物との混合溶液を調製する。ポリアミド酸溶液は公知の方法で製造することができる。即ちテトラカルボン酸二無水物類と芳香族ジアミン類を実質等モル使用し有機極性溶媒中で重合して得られる。
【００２１】
ポリアミド酸の生成反応に使用される有機溶剤としては、ジメチルスルホキシド、ジエチルスルホキシド等のスルホキシド系溶媒、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド等のホルムアミド系溶媒、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド等のアセトアミド系溶媒、Ｎ−メチル−２−ピロリドン、Ｎ−ビニル−２−ピロリドン等のピロリドン系溶媒、フェノ−ル、ｏ−，ｍ−，またはｐ−クレゾ−ル等のフェノ−ル系溶媒等を挙げることができ、これらを単独または混合物として用いるのが望ましいが、更にキシレン、トルエンのような芳香族炭化水素の使用も可能である。また、このポリアミド酸は、前記の有機極性溶媒中に１〜４０重量％、好ましくは５〜２５重量％溶解されているのが取り扱いの面からも望ましい。
【００２２】
ポリアミド酸の重合においてポリアミド酸の重量平均分子量は、特に限定されないが１５万以上が好ましく、２０万以上が更に好ましい。重量平均分子量が１５万以下であると、強度に劣るポリイミドフィルムが得られるからである。ポリイミド樹脂１００重量部に対する上記層間化合物の重量部は、弾性率や引張破断のびで示す靭性等の特性バランスの点で０．１〜２０重量部の範囲となるように混合させるのが好ましく、１〜１５重量部が更に好ましい。０．１重量部未満であると、弾性率等特性の向上が見られず、逆に２０重量部を超えると靭性の低下が顕著になるからである。
【００２３】
ポリアミド酸溶液と層間化合物の混合方法については、特に制限はなく、ポリアミド酸溶液に上記層間化合物を固体状で添加する方法あるいは有機溶媒に予め分散させた溶液の状態で添加する方法のいずれの方法でもよいが、添加後に均一になるまで混練機などにより機械的剪断下で攪拌することが肝要である。
【００２４】
また、層間化合物は、任意の段階で添加することができる。例えば、重合前のポリアミド酸の原料溶液に添加する方法、あるいは重合途中段階に添加する方法、更には、ポリアミド酸を熱的あるいは化学的にイミド化した後に添加する方法、即ちイミド樹脂溶液に添加する方法などを用いることができる。このポリアミド酸と層間化合物の混合溶液から本発明のポリイミド系フィルムを得るには、（１）熱的に脱水しイミド化する熱的方法と（２）脱水剤を用いる化学的方法のいずれを用いてもよいが、伸びや強度などの機械的特性の優れる複合体を得やすい化学的方法による方がより好ましい。
【００２５】
ポリアミド酸と層間化合物の混合溶液からポリイミドフィルムを製造する方法を例示する。（１）上記混合溶液をドラムあるいはエンドレスベルト上に流延または塗布して膜状とし、その膜を自己支持性を有するまで１５０℃以下の温度で約５分〜６０分乾燥させる。ついで、これを支持体から引き剥がし端部を固定した後、膜の収縮を制限しながら約１００℃〜５００℃のまで徐々に加熱することにより乾燥及びイミド化し、冷却後これより取り外し本発明のポリイミドフィルムを得る。
【００２６】
上記製造方法において、自己支持性を有するフィルムを支持体から剥がれやすくするためにポリアミド酸と層間化合物の混合溶液にかえて混合溶液に更に剥離剤を加えた混合溶液を用いてもよい。剥離剤としては、例えばジエチレングリコ−ルジメチルエ−テル、トリエチレングリコ−ルジメチルエ−テル等の脂肪族エ−テル類、ピリジン、ピコリンなどの３級アミン類、トリフェニルホスフィン、トリフェニルホスフェ−ト等の有機りん化合物類が挙げられる。
【００２７】
また化学的方法によりポリイミドフィルムを得る場合は、ポリアミド酸と層間化合物の混合溶液に代えて、混合溶液に更に化学量論以上の脱水剤と触媒量の３級アミン類を加えた混合溶液を用いればよい。脱水剤としては、例えば無水酢酸、無水フタル酸などの脂肪族あるいは芳香族酸無水物類が挙げられる。触媒としては、例えばトリエチルアミンなどの脂肪族３級アミン、ピリジン、ピコリン、イソキノリン等の複素環式３級アミン類が挙げられる。
【００２８】
フィルムを乾燥またはイミド化させる際に延伸してもよい。延伸することにより機械的特性に優れるフィルムを得やすいからである。ポリイミド系樹脂組成物に接着性や耐熱性、または滑り性等の各種特性を向上させることを目的に、複合体中に、酸化チタン、炭酸カルシウム、アルミナ、シリカゲル等の層間化合物以外の微粒子を含有させたり、複合体表面を、シランカップリング剤などの表面改質剤や微粒子とバインダ−樹脂を含む溶液等を塗布したり、コロナ処理やプラズマ処理などの放電処理などを施してもよい。
【００２９】
【実施例】
ＯＤＡは、４，４'−ジアミノジフェニルエ−テル、ＰＭＤＡはピロメリット酸二無水物、ＯＤＰＡは３，３'，４，４'−ジフェニルエ−テルテトラカルボン酸二無水物、ＢＰＤＡは、３，３'、４，４'−ジフェニルテトラカルボン酸二無水物、ＮＭＰはＮ−メチル−２−ピロリドンを表す。
【００３０】
またメチル−ＰＥＧは、一般式（１）中のＹがメチル基であるエチレングリコ−ル鎖を示す。
（ポリアミド酸溶液の調製 Ａ−１）室温下に、ＯＤＡ０．０８ｍｏｌとパラフェニレンジアミン０．０２ｍｏｌのＮＭＰ溶液にＰＭＤＡ０．０９５ｍｏｌを加え、窒素雰囲気で１時間攪拌した。次に、この溶液にゆっくりとＰＭＤＡ ０．００５ｍｏｌのＮＭＰ溶液を加えて１５重量％のポリアミド酸溶液を得た。
（ポリアミド酸溶液の調製 Ａ−２）室温下に、パラフェニレンジアミン０．１ｍｏｌのＮＭＰ溶液にＯＤＰＡ ０．０９５ｍｏｌを加え、窒素雰囲気で１時間攪拌した。次に、この溶液にゆっくりとＯＤＰＡ ０．００５ｍｏｌのＮＭＰ溶液を加えて１５重量％のポリアミド酸溶液を得た。
（ポリアミド酸溶液の調製 Ａ−３）室温下に、パラフェニレンジアミン０．１ｍｏｌのＮＭＰ溶液にＢＰＤＡ ０．０９５ｍｏｌを加え、窒素雰囲気で１時間攪拌した。次に、この溶液にゆっくりとＢＰＤＡ ０．００５ｍｏｌのＮＭＰ溶液を加えて１５重量％のポリアミド酸溶液を得た。
(層間化合物分散液の調製Ｂ−１)クニピアＦ（天然モンモリロナイト、ＣＥＣ＝１２０、クニミネ工業株式会社製） １００ｇを１０リットルの水に攪拌分散させた液に、ＣＥＣの１．５当量のメチルドデシルＰＥＧアンモニウムイオン塩酸塩を添加して２時間攪拌した。
【００３１】
析出した固体をろ別し次いで２５リットルの水に移し攪拌洗浄後ろ別した。この洗浄とろ別の操作を３回行った。最後に洗液を用い硝酸銀試験を行ったところ塩素イオンが無いことが確認された。得られた固体を５日間風乾し、更に熱風オ−ブンを用い５０℃で６時間乾燥させて、メチルドデシルビスＰＥＧアンモニウムイオンを含むクニピアＦを得た。得られたメチルドデシルビスＰＥＧアンモニウムイオンを含むクニピアＦをＮＭＰに攪拌分散させて、濃度が５重量％の有機化クニピアＦのＮＭＰ分散液を得た。
（層間化合物分散液の調製 Ｂ−２）メチルドデシルＰＥＧアンモニウムニウムイオンの塩酸塩に代えてメチルドデシルビスＰＥＧホスホニウムイオン塩酸塩を用いて、原料調製例Ｂ−１と同様の操作によりメチルドデシルビスＰＥＧホスホニウムイオンを含むクニピアＦのＮＭＰ分散液を得た。
（層間化合物分散液の調製 Ｂ−３）メチルドデシルビスＰＥＧアンモニウムイオンの塩酸塩に代えてメチルジエチル（メチル−ＰＥＧ）アンモニウムイオン塩酸塩を用いて、原料調製例Ｂ−１と同様の操作によりメチルジエチル（メチル−ＰＥＧ）アンモニウムイオンを含むクニピアＦのＮＭＰ分散液を得た。
（層間化合物分散液の調製ｂ−４）メチルドデシルビスＰＥＧアンモニウムイオン塩酸塩をラウリルアミンの塩酸塩に代えて、原料調製例Ｂ−１と同様の操作によりラウリルアミンのアンモニウムイオンを含むクニピアＦのＮＭＰ分散液を得た。
（実施例１〜９）ポリアミド酸溶液 Ａ−１〜Ａ−３１００重量部と層間化合物分散液 Ｂ−１〜Ｂ−３１５重量部を表１に示す組み合わせで混合しポリアミド酸と層間化合物を含む混合溶液を調製した。
【００３２】
得られたポリアミド酸と層間化合物を含む混合溶液からポリイミドフィルムを作製した。フィルムの作製は、以下のようにして行う。１００ｇの混合溶液に無水酢酸１５ｇ、β−ピコリン５ｇ、ＮＭＰ１０ｇを加え充分攪拌した後、ＰＥＴフィルム上にコ−タ−で塗布し、８０℃で１０分間加熱し自己支持性を有する膜を得た。この膜をＰＥＴから剥したのち、端部を固定して１００℃〜４５０℃へ連続的に加熱し、更に４５０℃で５分間加熱しイミド化させて、透明性良好な厚みが１５μｍの層間化合物を含有するポリイミドフィルム得た。
【００３３】
得られたポリイミドフィルムのフィルム中に含まれる層間化合物の大きさを、透過型電子顕微鏡（倍率：１０万倍）を用いて４μm²の範囲での層間化合物の層厚みを観察することにより評価した。その結果を表１に示す。更に得られたフィルムを用い引張試験をＡＳＴＭＤ−８８２に準拠しフィルムの弾性率、破断強度及び最大伸び率を求めた。その結果を表１に示した。
【００３４】
（比較例１）ポリアミド酸溶液 Ａ−１、１００重量部に層間化合物分散液 ｂ−４、１５重量部を配合し、ポリアミド酸と層間化合物を含む混合溶液を調製した。 得られたポリアミド酸と層間化合物を含む混合溶液から、実施例と同様に化学的方法によりポリイミドフィルムを作製した。実施例と同様に層間化合物の層厚みを評価し、実施例と同様の試験により、得られたフィルムのフィルムの弾性率と伸び率、強度を求めた。その結果を表１に示した。
【００３５】
（比較例２）ポリアミド酸溶液 Ａ−２、１００重量部に層間化合物分散液 ｂ−４ １５重量部を配合し、ポリアミド酸と層間化合物を含む混合溶液を調製した。得られたポリアミド酸と層間化合物を含む混合溶液から、実施例と同様に化学的方法によりポリイミドフィルムを作製した。実施例と同様に層間化合物の層厚みを評価し、実施例と同様の試験により、得られたフィルムのフィルムの弾性率と伸び率、強度を求めた。その結果を表１に示した。
（比較例３）ポリアミド酸溶液 Ａ−３、１００重量部に層間化合物分散液 ｂ−４ １５重量部を配合し、ポリアミド酸と層間化合物を含む混合溶液を調製した。
【００３６】
得られたポリアミド酸と層間化合物を含む混合溶液から、実施例と同様に化学的方法によりポリイミドフィルムを作製した。実施例と同様に層間化合物の層厚みを評価し、実施例と同様の試験により、得られたフィルムの弾性率と伸び率、強度を求めた。その結果を表１に示した。
【００３７】
【発明の効果】
以上のように、本発明のポリイミド系フィルムは、ポリイミド樹脂中に特定の層間化合物が分散していることにより、弾性率、破断強度及び最大伸び率が向上している。
【００３８】
【表１】

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyimide film containing an intercalation compound having an organic onium ion having an ethylene glycol chain as a guest.
[0002]
[Prior art]
Since polyimide films are excellent in heat resistance and electrical insulation properties, they are often used as electronic materials such as flexible printed wiring boards and base films for lead-on-chip tapes in semiconductor devices. However, in recent years, along with the downsizing, thinning, and weight reduction of electronic devices such as computers and mobile phones, there has been a strong demand for downsizing, thinning, and weight reduction of electronic components used in them. . Therefore, an extremely thin film having a thickness of 10 microns or less is required for a polyimide film as a material for electronic components. However, in the conventional polyimide film, the elastic modulus is insufficient and thinning is difficult, and improvement in the elastic modulus and strength is required.
[0003]
As a method for improving the elastic modulus and strength of a resin, a method is known in which an intercalation compound containing organic onium ions as a guest is uniformly dispersed in the resin (Japanese Patent Laid-Open No. 7-166036). As for the polyimide resin, a film in which an intercalation compound is uniformly dispersed has been proposed (Japanese Patent Laid-Open No. 4-33955).
[0004]
[Problems to be solved by the invention]
However, in JP-A-4-33955, an intercalation compound using alkylammonium ions such as laurylamine ion and myristylamine ion as a guest is dispersed in a polyimide resin to improve gas barrier properties and thermal expansion coefficient. There is no description about rate or strength. In addition, interlaminar compounds in which alkyl group and polyimide resin have low affinity and alkylammonium ion as guest, the dispersibility deteriorates rapidly when the intercalation compound aggregates in polyimide resin or the composition of polyimide resin is different. There is.
[0005]
[Means for Solving the Problems]
The present invention is a polyimide film containing an intercalation compound having an organic onium ion having an ethylene glycol chain as a guest and having an elastic modulus of 540 kg / mm ² or more . Moreover, this invention is a polyimide-type film whose layer thickness of the interlayer compound which uses an organic onium ion as a guest is 20 nm or less. Furthermore, the present invention provides a polyimide system obtained by casting or applying a polyamic acid solution or an imide resin solution to which an intercalation compound having an organic onium ion having an ethylene glycol chain as a guest is added to form a film. It is a film.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The polyimide film of the present invention is a polyimide film containing an intercalation compound having an organic onium ion having an ethylene glycol chain as a guest. The polyimide film of the present invention is characterized in that an organic onium ion having an ethylene glycol chain is used as a guest. Since the guest has an ethylene glycol chain, the interlayer compound is finely dispersed in the polyimide (interlayer compound). The thickness is small) and the content of the intercalation compound can be increased.
[0007]
An organic onium ion having an ethylene glycol chain as a guest of an intercalation compound refers to a compound having an organic onium ion and an ethylene glycol chain. The organic onium ion has a structure represented by ammonium ions, phosphonium ions, sulfonium ions, and onium ions derived from heteroaromatic rings. In the presence of onium ions, an organic structure having a small intermolecular force can be introduced between the negatively charged layered silicate layers to increase the affinity between the layered silicate and the polyimide resin. The organic onium ion may have both a polyimide chain, a polyamide chain, a polyester chain, a polyacrylate chain, and a polyphenylene ether chain in order to further improve polyimide affinity.
[0008]
The ethylene glycol chain means the following general formula (1)
[0009]
[Formula 4]

[0010]
(Wherein Y represents H, a methyl group or a halogen group, R ₁ represents H, an alkyl group having 18 or less carbon atoms or a phenyl group, and a represents an integer of 1 or more). The terminal of the ethylene glycol chain may be a hydroxyl group, an alkyl group, or a phenyl group, but preferably the hydroxyl group hydrogen is substituted with an alkyl group or a phenyl group. This is because the polyamic acid causes a hydrolysis reaction with a compound having a hydroxyl group such as water or alcohols and impairs the storage stability of the polyamic acid.
[0011]
As an organic onium ion having an ethylene glycol chain, a primary ammonium ion such as PEG ammonium (hereinafter, PEG represents an ethylene glycol chain in which Y in the general formula (1) is hydrogen), methyl PEG ammonium Secondary ammonium ions such as dodecyl PEG ammonium, tertiary ammonium ions such as dimethyl PEG ammonium and methyl dodecyl PEG ammonium, and quaternary ammonium ions such as dimethyl bis PEG ammonium, diethyl bis PEG ammonium, dibutyl bis PEG ammonium, methyl ethyl bis PEG ammonium, etc. Dialkyl bis PEG ammonium, dimethyl bis PEG phosphonium, diethyl bis PEG phosphonium, dibutyl bis PEG phosphonium, methyl ethyl bis PEG Dialkylbis PEG phosphonium ions such Suhoniumu, methyltris PEG ammonium, Echirutorisu PEG ammonium, alkyl tris PEG ammonium ions such Buchirutorisu PEG ammonium, methyltris PEG phosphonium, Echirutorisu PEG phosphonium, alkyl tris PEG phosphonium ions such Buchirutorisu PEG phosphonium.
[0012]
Of these, dialkyl bis PEG ammonium ions such as dimethyl bis PEG ammonium and methyl dodecyl bis PEG ammonium, and dialkyl bis PEG such as dimethyl bis PEG phosphonium and methyl dodecyl bis phosphonium due to affinity with polyimide, heat resistance, and availability. Phosphonium ions are preferred. In particular, a quaternary onium ion is preferable in that an intercalation compound hardly aggregates in a polyimide resin matrix.
[0013]
The intercalation compound used in the present invention is obtained by allowing an organic onium ion having an ethylene glycol chain to act on a layered silicate. Layered silicates include smectite clay minerals such as montmorillonite, hectorite, fluorine hectorite, saponite, beidellite, stevensite, Li-type fluorine teniolite, Na-type fluorine teniolite, Na-type tetrasilicon fluorine mica, Li-type tetrasilicon fluorine mica Swelling synthetic mica, vermiculite, fluorine vermiculite, halloysite and the like may be mentioned, and these may be natural or synthesized, and these may be used alone or in combination. The layered silicate includes a partly cleaved layered silicate as well as a united structure. The unit structure of the layered silicate is preferably a 2: 1 type in which an octahedral sheet structure containing Al, Mg, Li, Na, etc. is sandwiched between two SiO ₄ tetrahedral sheet structures, The thickness of one layer which is the unit structure is usually about 1 nm.
[0014]
The cation exchange capacity (CEC) of the layered silicate is preferably in the range of 40 to 300 meq / 100 g, and more preferably in the range of 50 to 200 meq / 100 g. When the CEC is less than 40 meq / 100 g, the amount of organic onium ions inserted between layers becomes insufficient, the affinity with the polyimide resin decreases, and the dispersibility in the polyimide resin deteriorates. On the other hand, if the CEC is greater than 300 meq / 100 g, the interlayer bonding force of the layered silicate is too strong, making it difficult to expand the layered silicate between layers, resulting in poor dispersibility in the polyimide resin. If the dispersibility is poor, the properties such as strength and toughness of the composition are not sufficiently improved, and the appearance of the molded surface is significantly impaired.
[0015]
The intercalation compound used in the present invention is a compound in which an organic onium ion having an ethylene glycol chain is inserted between layered silicate layers such as montmorillonite and smectite. Such an intercalation compound is a known technique for reacting an organic onium ion with a layered clay mineral containing a negative layer lattice and exchangeable cations (for example, Japanese Patent Publication No. 61-5492, Japanese Patent Laid-Open No. 60-42451). Japanese Patent Application No. 6-231748 (Japanese Patent Application Laid-Open No. 8-12881), Japanese Patent Application No. 6-231746 (Japanese Patent Application Laid-Open No. 7-166036) and the like.
[0016]
A polyimide resin is a polyimide resin obtained by dehydrating a polyamic acid obtained by a condensation reaction between a tetracarboxylic dianhydride and a diamine. Examples of tetracarboxylic dianhydrides include pyromellitic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride, 1,4-hydroquinone dibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride, A seed or a mixture of two or more may be used.
[0017]
Examples of diamines include paraphenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzanilide, and 2,2-bis [(4-aminophenoxy) phenyl] propane. A seed or a mixture of two or more may be used. The manufacturing method of the polyimide-type film of this invention is demonstrated.
[0018]
General formula that is a polyimide precursor
[Chemical formula 5]

[0020]
(In the formula, R ₆ represents a tetravalent organic group, and R ₇ represents a divalent organic group.) A mixed solution of a polyamic acid and an intercalation compound is prepared. The polyamic acid solution can be produced by a known method. That is, it is obtained by polymerizing tetracarboxylic dianhydrides and aromatic diamines in an organic polar solvent using substantially equimolar amounts.
[0021]
Examples of the organic solvent used in the polyamic acid production reaction include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and N, N-dimethylacetamide. Acetamide solvents such as N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m-, or p-cresol Examples thereof include phenolic solvents such as these, and it is desirable to use these alone or as a mixture, but it is also possible to use aromatic hydrocarbons such as xylene and toluene. Further, it is desirable from the viewpoint of handling that the polyamic acid is dissolved in the organic polar solvent in an amount of 1 to 40% by weight, preferably 5 to 25% by weight.
[0022]
In the polymerization of the polyamic acid, the weight average molecular weight of the polyamic acid is not particularly limited, but is preferably 150,000 or more, and more preferably 200,000 or more. This is because when the weight average molecular weight is 150,000 or less, a polyimide film having poor strength can be obtained. The amount of the intercalation compound relative to 100 parts by weight of the polyimide resin is preferably mixed so as to be in the range of 0.1 to 20 parts by weight in terms of a balance of properties such as elasticity and toughness as indicated by tensile fracture. More preferred is ˜15 parts by weight. If the amount is less than 0.1 parts by weight, the improvement of the properties such as the elastic modulus is not observed. Conversely, if the amount exceeds 20 parts by weight, the toughness is significantly lowered.
[0023]
The mixing method of the polyamic acid solution and the intercalation compound is not particularly limited, and either the method of adding the intercalation compound as a solid to the polyamic acid solution or the method of adding it in the form of a solution dispersed in an organic solvent in advance. However, it is important to stir under mechanical shearing with a kneader or the like until uniform after the addition.
[0024]
The intercalation compound can be added at an arbitrary stage. For example, a method of adding to a raw material solution of polyamic acid before polymerization, a method of adding in the middle of polymerization, or a method of adding polyamic acid after thermal or chemical imidization, that is, adding to an imide resin solution Or the like can be used. In order to obtain the polyimide film of the present invention from the mixed solution of the polyamic acid and the intercalation compound, either (1) a thermal method of thermally dehydrating and imidizing or (2) a chemical method using a dehydrating agent is used. However, it is more preferable to use a chemical method that facilitates obtaining a composite having excellent mechanical properties such as elongation and strength.
[0025]
A method for producing a polyimide film from a mixed solution of polyamic acid and an intercalation compound will be exemplified. (1) The mixed solution is cast or coated on a drum or endless belt to form a film, and the film is dried at a temperature of 150 ° C. or lower for about 5 to 60 minutes until it has self-supporting properties. Then, after peeling off this from the support and fixing the end, it is dried and imidized by gradually heating to about 100 ° C. to 500 ° C. while restricting the shrinkage of the membrane, and after cooling it is removed from it and removed from this. A polyimide film is obtained.
[0026]
In the above production method, a mixed solution in which a release agent is further added to the mixed solution may be used instead of the mixed solution of the polyamic acid and the interlayer compound in order to make the film having self-supporting property easy to peel from the support. Examples of the release agent include aliphatic ethers such as diethylene glycol dimethyl ether and triethylene glycol dimethyl ether, tertiary amines such as pyridine and picoline, triphenyl phosphine, and triphenyl phosphate. Organophosphorus compounds are mentioned.
[0027]
When a polyimide film is obtained by a chemical method, instead of a mixed solution of polyamic acid and an intercalation compound, a mixed solution in which a dehydrating agent of a stoichiometric amount or more and a catalytic amount of a tertiary amine are further added to the mixed solution is used. That's fine. Examples of the dehydrating agent include aliphatic or aromatic acid anhydrides such as acetic anhydride and phthalic anhydride. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline.
[0028]
The film may be stretched when it is dried or imidized. This is because it is easy to obtain a film having excellent mechanical properties by stretching. Containing fine particles other than intercalation compounds such as titanium oxide, calcium carbonate, alumina, and silica gel in the composite for the purpose of improving various properties such as adhesion, heat resistance, and slipperiness in the polyimide resin composition The surface of the composite may be applied with a surface modifier such as a silane coupling agent, a solution containing fine particles and a binder resin, or a discharge treatment such as a corona treatment or a plasma treatment.
[0029]
【Example】
ODA is 4,4′-diaminodiphenyl ether, PMDA is pyromellitic dianhydride, ODPA is 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride, BPDA is 3 , 3 ′, 4,4′-diphenyltetracarboxylic dianhydride, NMP represents N-methyl-2-pyrrolidone.
[0030]
Methyl-PEG represents an ethylene glycol chain in which Y in the general formula (1) is a methyl group.
(Preparation of Polyamic Acid Solution A-1) At room temperature, 0.095 mol of PMDA was added to an NMP solution of 0.08 mol of ODA and 0.02 mol of paraphenylenediamine, and stirred for 1 hour in a nitrogen atmosphere. Next, PMDA 0.005 mol of NMP solution was slowly added to this solution to obtain a 15 wt% polyamic acid solution.
(Preparation of polyamic acid solution A-2) At room temperature, 0.095 mol of ODPA was added to an NMP solution of 0.1 mol of paraphenylenediamine, and the mixture was stirred for 1 hour in a nitrogen atmosphere. Next, ODPA 0.005 mol of NMP solution was slowly added to this solution to obtain a 15 wt% polyamic acid solution.
(Preparation of Polyamic Acid Solution A-3) Under room temperature, 0.095 mol of BPDA was added to an NMP solution of 0.1 mol of paraphenylenediamine and stirred for 1 hour in a nitrogen atmosphere. Next, BPDA 0.005 mol of NMP solution was slowly added to this solution to obtain a 15 wt% polyamic acid solution.
(Preparation of Intercalation Compound Dispersion B-1) Kunipia F (natural montmorillonite, CEC = 120, manufactured by Kunimine Kogyo Co., Ltd.) In a solution obtained by stirring and dispersing 100 g in 10 liters of water, 1.5 equivalents of methyl dodecyl of CEC PEG ammonium ion hydrochloride was added and stirred for 2 hours.
[0031]
The precipitated solid was separated by filtration, then transferred to 25 liters of water and separated after stirring and washing. This washing and filtering operation was performed three times. Finally, a silver nitrate test was performed using the washing solution, and it was confirmed that there was no chloride ion. The obtained solid was air-dried for 5 days and further dried at 50 ° C. for 6 hours using a hot air oven to obtain Kunipia F containing methyldodecylbisPEGammonium ions. The obtained Kunipia F containing methyldodecylbisPEG ammonium ion was stirred and dispersed in NMP to obtain an NMP dispersion of Organized Kunipia F having a concentration of 5% by weight.
(Preparation of Intercalation Compound Dispersion B-2) Methyldodecyl bis PEG was prepared in the same manner as in Raw Material Preparation Example B-1, using methyl dodecyl bis phosphonium ion hydrochloride instead of methyl dodecyl PEG ammonium ion hydrochloride. An NMP dispersion of Kunipia F containing phosphonium ions was obtained.
(Preparation of Intercalation Compound Dispersion B-3) Methyldiethyl (methyl-PEG) ammonium ion hydrochloride was used instead of methyldodecylbisPEGammonium ion hydrochloride, and methylation was performed in the same manner as in Raw Material Preparation Example B-1. An NMP dispersion of Kunipia F containing diethyl (methyl-PEG) ammonium ion was obtained.
(Preparation of Intercalation Compound Dispersion b-4) By replacing methyldodecyl bis PEG ammonium ion hydrochloride with hydrochloride of laurylamine, the same procedure as in Raw Material Preparation Example B-1 was carried out to obtain Kunipia F containing ammonium ion of laurylamine. An NMP dispersion was obtained.
(Examples 1-9) Polyamic acid solution A-1 to A-3100 parts by weight and intercalation compound dispersion B-1 to B-315 parts by weight are mixed in the combinations shown in Table 1 and mixed to contain polyamic acid and intercalation compounds A solution was prepared.
[0032]
A polyimide film was prepared from the mixed solution containing the obtained polyamic acid and an intercalation compound. The film is produced as follows. To 100 g of the mixed solution, 15 g of acetic anhydride, 5 g of β-picoline and 10 g of NMP were added and stirred sufficiently, and then coated on a PET film with a coater and heated at 80 ° C. for 10 minutes to obtain a film having self-supporting properties. . After peeling off this film from PET, the end is fixed and continuously heated to 100 ° C. to 450 ° C., further heated at 450 ° C. for 5 minutes to imidize, and an interlayer compound having a thickness of 15 μm with good transparency. A polyimide film containing was obtained.
[0033]
The size of the interlayer compound contained in the obtained polyimide film was evaluated by observing the layer thickness of the interlayer compound in the range of 4 μm ² using a transmission electron microscope (magnification: 100,000 times). . The results are shown in Table 1. Further, using the obtained film, a tensile test was performed according to ASTM D-882, and the elastic modulus, breaking strength and maximum elongation of the film were determined. The results are shown in Table 1.
[0034]
(Comparative Example 1) Polyamic acid solution A-1 was mixed with 100 parts by weight of intercalation compound dispersion b-4 and 15 parts by weight to prepare a mixed solution containing polyamic acid and intercalation compound. A polyimide film was produced from the obtained mixed solution containing the polyamic acid and the intercalation compound by a chemical method in the same manner as in the Examples. The layer thickness of the interlayer compound was evaluated in the same manner as in the Examples, and the elastic modulus, elongation, and strength of the obtained film were determined by the same test as in the Examples. The results are shown in Table 1.
[0035]
(Comparative Example 2) Polyamic acid solution A-2, 15 parts by weight of intercalation compound dispersion b-4 was blended with 100 parts by weight to prepare a mixed solution containing the polyamic acid and the intercalation compound. A polyimide film was produced from the obtained mixed solution containing the polyamic acid and the intercalation compound by a chemical method in the same manner as in the Examples. The layer thickness of the interlayer compound was evaluated in the same manner as in the Examples, and the elastic modulus, elongation, and strength of the obtained film were determined by the same test as in the Examples. The results are shown in Table 1.
(Comparative Example 3) Polyamic acid solution A-3, 15 parts by weight of intercalation compound dispersion b-4 was blended with 100 parts by weight to prepare a mixed solution containing the polyamic acid and the intercalation compound.
[0036]
A polyimide film was produced from the obtained mixed solution containing the polyamic acid and the intercalation compound by a chemical method in the same manner as in the Examples. The layer thickness of the interlayer compound was evaluated in the same manner as in the Examples, and the elastic modulus, elongation, and strength of the obtained film were determined by the same test as in the Examples. The results are shown in Table 1.
[0037]
【The invention's effect】
As described above, in the polyimide-based film of the present invention, the elastic modulus, breaking strength, and maximum elongation are improved because the specific interlayer compound is dispersed in the polyimide resin.
[0038]
[Table 1]

Claims (3)

The following general formula

(In the formula, Y represents H, a methyl group or a halogen group, R ₁ represents H, an alkyl group having 18 or less carbon atoms or a phenyl group, and a represents an integer of 1 or more.)
An intercalation compound having an organic onium ion having an ethylene glycol chain represented by
A polyimide-based film having an elastic modulus of 540 kg / mm ² or more.   2. The polyimide-based film according to claim 1, wherein the layer thickness of 90% or more of the intercalation compound is 20 nm or less. The organic onium ion having the ethylene glycol chain is

(In the figure, R ₂ , R ₃ and R ₄ independently represent H or an alkyl group having 18 or less carbon atoms, or a phenyl group, R ₅ represents an organic group, m represents an integer of 1 or more, n, (s is an integer greater than or equal to 0, and is 1 <m + n + s <60. X shows a nitrogen atom or a phosphorus atom.)
The polyimide-based film according to claim 1, wherein the polyimide-based film is represented by: