JP3729315B2 - Manufacturing method and manufacturing apparatus for polyimide film - Google Patents

Description

【００１６】
の繰り返し単位を有するポリイミドに適用される。
【００１７】
式中、Ｒ₁ は４価の有機基であり、具体的には、少なくとも１個の芳香族を有してなり、かつ結合すべき隣接するカルボニル基とは芳香環が直接結合してなる。さらに具体的には、化２
【００１８】
【化２】

【００１９】
（式中、Ｘは化３
【００２０】
【化３】

【００２１】
から選択される２価の官能基であり、Ｒ₄ は、ＣＨ₃ −、Ｃｌ−、Ｂｒ−、Ｆ−、ＣＨ₃ Ｏ−であり、２以上置換される場合は、Ｒ₄ は同一であってもよくまた異なってもよい。）で表される群から選ばれる少なくとも１種である。
【００２２】
また、式中、Ｒ₂ は２価の有機基、具体的には少なくとも１個の芳香族を有してなり、さらに、具体的には、化４
【００２３】
【化４】

【００２４】
（式中、Ｒ₄ は、ＣＨ₃ −、Ｃｌ−、Ｂｒ−、Ｆ−、ＣＨ₃ Ｏ−であり、２以上置換される場合は、Ｒ₄ は同一であってもよくまた異なってもよい。）で表される群から選ばれる少なくとも１種である。
【００２５】
特に好ましいポリイミドは、式中、Ｒ₁ が、化５
【００２６】
【化５】

【００２７】
で、Ｒ₂ が、化６
【００２８】
【化６】

【００２９】
を主成分とするポリイミド、あるいは、式中、Ｒ₁ が、化７
【００３０】
【化７】

【００３１】
で、Ｒ₂ が、化８
【００３２】
【化８】

【００３３】
と、化９
【００３４】
【化９】

【００３５】
を各々主成分とするポリイミド共重合体に適用される。
【００３６】
さらに好ましくは、化１０
【００３７】
【化１０】

【００３８】
と化１１
【００３９】
【化１１】

【００４０】
のモル比が、数１
【００４１】
【数１】

【００４２】
の範囲のものである。また、Ｒ₁ が、化１２
【００４３】
【化１２】

【００４４】
で、Ｒ₂ が、化１３
【００４５】
【化１３】

【００４６】
を主成分とするものや、Ｒ₁ が、化１４
【００４７】
【化１４】

【００４８】
と、化１５
【００４９】
【化１５】

【００５０】
で、Ｒ₂ が、化１６
【００５１】
【化１６】

【００５２】
と、化１７
【００５３】
【化１７】

【００５４】
を各々主成分とするポリイミド共重合体にも適用可能である。
【００５５】
以下、ポリイミド樹脂の製造方法について説明する。上記一般式（１）で表されるポリイミド樹脂は、その前駆体であるポリアミド酸重合体を脱水閉環して得られるが、このポリアミド酸溶液は、従来公知の方法により、酸二無水物とジアミン成分を実質的に等モル使用し、有機極性溶媒中で重合して得られる。
【００５６】
まず、ポリアミド酸の製法について述べる。まず、アルゴン、窒素などの不活性ガス雰囲気中において、一般式（２）化１８
【００５７】
【化１８】

【００５８】
（式中、Ｒ₁ は４価の有機基を示す。）で表される芳香族テトラカルボン酸二無水物中より、少なくとも１成分以上の酸二無水物を有機溶媒中に溶解し、または、拡散させる。この溶液に、一般式（３）
Ｈ₂ Ｎ−Ｒ₂ −ＮＨ₂ （３）
（式中、Ｒ₂ は２価の有機基を示す。）で表される少なくとも１種以上のジアミン成分を有機溶媒に溶解、あるいは、スラリー状に拡散させた状態で、または、固体の状態で添加し、ポリアミド酸重合体の溶液を得る。
【００５９】
この時の反応温度は、−１０℃から５０℃が好ましい。反応時間は、３０分から６時間程度である。
【００６０】
また、この反応において、上記添加順序とは逆に、まず、ジアミン成分を拡散又は溶解させ、該溶液中に酸二無水物の固体もしくは有機溶媒による溶液もしくはスラリーを添加してもよい。
【００６１】
なお、生成されるポリイミド樹脂の強度を維持するためには、数平均分子量が１万以上が好ましい。ポリイミド重合体の分子量は直接測定が困難な場合が多い。このようなときには間接的な方法によって推測による測定がなされる。たとえば、ポリイミド重合体がポリアミド酸から合成される場合には、ポリアミド酸の分子量に相当する値をポリイミドの分子量とする。
【００６２】
また、一般式（２）化１９
【００６３】
【化１９】

【００６４】
で表される芳香族テトラカルボン酸二無水物としては、本質的に種々のテトラカルボン酸二無水物が使用可能であるが、より具体的には、諸特性のバランスから、一般式（２）中のＲ₁ が、化２０
【００６５】
【化２０】

【００６６】
（式中、Ｘは化２１
【００６７】
【化２１】

【００６８】
で表される２価の官能基である。式中、Ｒ₄ は、ＣＨ₃ −、Ｃｌ−、Ｂｒ−、Ｆ−、ＣＨ₃ Ｏ−であり、２以上置換される場合は、Ｒ₄ は同一であってもよく、また異なってもよい。）で表される４価の有機基を示す１種以上の芳香族テトラカルボン酸二無水物を選択することができる。
【００６９】
また、一般式（３）で表されるジアミン化合物としては、本質的に種々のジアミンが使用可能であるが、より具体的には、諸特性のバランスから、一般式（３）
Ｈ₂ Ｎ−Ｒ₂ −ＮＨ₂ （３）
中のＲ₂ が、化２２
【００７０】
【化２２】

【００７１】
（式中、Ｒ₄ は、ＣＨ₃ −、Ｃｌ−、Ｂｒ−、Ｆ−、ＣＨ₃ Ｏ−であり、２以上置換される場合は、Ｒ₄ は同一であってもよく、また異なってもよい。）で表される２価の有機基である１種以上のジアミンを選択することができる。
【００７２】
さらに、本発明に用いられ得る有機溶媒としては、例えば、ジメチルスルホキシド、ジエチルスルホキシドなど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など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など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−ピロリドンなどのピロリドン系溶媒、フェノール、ｏ−、ｍ−、またはｐ−クレゾール、キシレノール、ハロゲン化フェノール、カテコールなどのフェノール系溶媒、あるいはヘキサメチルホスホルアミド、γ−ブチロラクトンなどをあげることができ、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、更にはキシレン、トルエンのような芳香族炭化水素の一部使用も可能である。
【００７３】
なお、ポリアミド酸溶液を調製する際、あるいはポリアミド酸溶液を調製した後、または化学的方法による脱水剤及び触媒に酸化防止剤、光安定剤，難燃剤、帯電防止剤、熱安定剤、紫外線吸収剤、あるいは無機フィラー類、またはその他の強化剤等を混合し得る。
【００７４】
また、ポリイミドの製造方法は、前駆体であるポリアミド酸に無水酢酸等の酸無水物に代表される脱水閉環剤と、ピコリン、キノリン、イソキノリン、ピリジン等の第３級アミン類とを作用させるケミカルキュア法によってポリイミドに変換させる方法および、上記脱水剤等を作用させずに加熱のみでイミド化反応を進行させるいわゆる熱キュア法も用い得る。さらに両者を併用した方法も用い得る。
【００７５】
ケミカルキュア法及び熱キュア法を組み合わせた場合、通常、工程の前半は主にケミカルキュア法が行われ、引き続き後半の熱キュア法でイミド化を完結する。
【００７６】
ここで、本発明における「ゲルフィルム」とは、前半のケミカルキュアの工程が終了した段階のフィルム、あるいは熱キュア法による熱キュア工程に入る前のフィルムと定義する。
【００７７】
ポリイミド前駆体をイミド化し、最終的にポリイミドフィルムの製品とするための製造装置は、流延塗布しケミカルキュアを行う加熱手段を備えたドラム室あるいはベルト室と熱キュアを行うテンター室とに大きく分けられる。
【００７８】
本発明にかかるポリイミドフィルムの製造工程の１例を図１により示すと、まずベルト室１０での工程は、ミキサーで混合したポリイミド前駆体をＴダイ１２によりフィルム状に押し出す工程を行い、反応硬化室においてはＴダイより押し出されたフィルム状のポリイミド前駆体をエンドレスベルトあるいはキャスティングドラム１４上にフィルム状に形成する。フィルム状に形成された前駆体は、ベルトあるいはドラムの回転により移動させられながら、加熱手段により加熱されてイミド化される。このベルト室内においては反応に伴って生成した生成物、主として酢酸や有機溶媒等の可燃性の揮発成分が蒸発する。
【００７９】
ベルト室１０での加熱手段は、樹脂から蒸散した可燃性の揮発成分に引火する危険を防止するため、あるいは樹脂自体が発火することを防止するために、雰囲気温度、およびベルトあるいはドラムの回転速度を調整しつつ加熱し、たとえば温風・ 熱風・放射熱・ベルト加熱等を用い得る。ベルト室での温度条件を例示すると、ベルト１室が１００℃、ベルト２室１２０℃、ベルト３室１３０℃、及び冷却プーリー２６が、８０℃等の温度条件により、キャストされたフィルムに自己支持性が付与される。
【００８０】
これらの工程により、ポリイミド前駆体のフィルムをイミド化しながら、フィルムが自己支持性を有する程度まで加熱・乾燥を行った後、エンドレスベルトまたはキャスティングドラムから引き剥がして、本発明にいうゲルフィルム１６を得る。
【００８１】
上記ゲルフィルム１６は端部を固定されテンター室１８にて加熱処理される。例えば、テンター室１８は、加熱炉２０及び徐冷炉２２で構成され、図１においては、ピンでフィルムを固定したピンシートをピンコンベアの回転駆動により可動させることにより、フィルムがテンター室内を移動する。熱キュアを行う加熱炉２０内において徐々に加熱することによりゲルフィルムをさらにイミド化する。
【００８２】
加熱炉２０は、たとえば、熱風炉、遠赤外線ヒーターが用いられ得る。
【００８３】
加熱炉２０内では、徐々に昇温して、ポリイミドへのイミド化を完了させる。
【００８４】
熱処理の温度は、初期設定温度はフィルムの膜厚、またポリイミド前駆体の反応に用いる有機溶媒の種類等との関係により、乾燥の程度が異なる。具体的には、初期設定温度は、例えば、最終膜厚２５μｍのフィルムにおいては、２００℃から２５０℃、最終膜厚１２５μｍのフィルムにおいては、１５０℃〜２００℃が好ましい。この段階で、ゲルフィルムの乾燥が効果的に行われ同時にイミド化反応が進行すると考えられる。
【００８５】
その後、徐々に加熱し最高温度５００℃以上６３０℃以下の温度範囲とすることが好ましい。さらに好ましくは、５４０℃以上５８０℃以下の範囲が好ましい。最高温度に達する温度勾配については、上記の温度範囲で熱処理を施せば、特に制限されない。 熱処理時間は、数秒から数十分、好ましくは１分から５分であり、熱処理温度との関係で適宜設定される。
【００８６】
温度勾配は、フィルム厚や乾燥の度合い等フィルムの状態に適応して設定され、特に限定されない。具体的に例をあげて説明すると、２５μｍの膜厚のフィルムでは、２００℃以上２５０℃以下の温度範囲で３０秒、さらに３００℃以上３５０℃以下の温度範囲で３０秒、４００℃以上４５０℃以下の温度範囲で３０秒、さらに５００℃以上５８０℃以下の温度範囲で６０秒である。
【００８７】
上記加熱炉２０内での熱キュアの工程において、完全にイミド化されたポリイミドフィルムは、除冷炉２２において徐々に冷却される。
【００８８】
本発明にかかる製造方法により得られるポリイミドフィルムは、厚み数μｍから数百μｍのシート状物を含む広義のフィルムを意味し、用途に応じてその厚みを選択することができる。例えば、フレキシブルプリント配線板のベースフィルム等として使用する場合は１２．５μｍ〜５０μｍ程度のフィルムが適用され得る。特に２５μｍ以下の膜厚を有するポリイミドフィルムの場合は、上記加熱炉の初期温度設定を、１５０℃〜２５０℃に設定することにより、接着性の向上に顕著に効果が発揮され得る。
【００８９】
上述のようにして、製造されたポリイミドフィルムは、ゲルフィルムの段階で有機溶媒溶液を多く含み、イミド化率が低いものについても、ゲルフィルムの段階において、フィルムの乾燥の程度やイミド化率を厳密に限定することなく、また、製品の後処理を行うことなく、製品であるポリイミドフィルムの段階において、顕著な接着性の向上が見られた。従って、本発明にかかるポリイミドフィルムの製造方法は、フィルム製造工程におけるゲルフィルムの段階での煩雑な乾燥度管理の工程を省略することができる画期的なポリイミドフィルム製造方法及び製造装置であり、最終製品であるポリイミドフィルムの接着強度の向上に効果的に寄与し得る。
【００９０】
以上、本発明にかかるポリイミドフィルムの製造方法の実施の形態の１例を説明したが、本発明はこれら実施の形態のみに限定されず、本発明の趣旨を逸脱しない範囲内で当業者の知識に基づき、種々なる改良、変更、修正を加えた態様で実施し得るものである。
【００９１】
【実施例】
以下、本発明にかかるポリイミドフィルムの製造方法について、具体的に実施例を示す。本発明は、これらの実施例に限定されるものではない。
【００９２】
なお、実施例において、測定される接着強度の測定法は、以下の方法で評価した。アクリル系接着剤（デュポン（株）製；パイラックス）を用いてフィルムと銅箔（三井金属鉱業（株）製電解銅箔；３ＢＣ ３５μｍ厚）とをラミネートし、１８５℃×１時間で接着剤の硬化反応を行い、ＦＣＣＬの銅パターン幅が３ｍｍとなるようにサンプルを切り出し、引張試験器（島津製作所（株）製；Ｓ−１００−Ｃ）によりピールテストスピード５０ｍｍ／ｍｉｎで９０度剥離試験を行った。ｎ＝５の平均値による測定結果を表に表した。
【００９３】
また、実施例において、ポリイミドフィルムに施したコロナ処理は、アルミニウム電極を用いて電力密度を２２０±１０Ｗ・min/ｍ² で処理した。
【００９４】
【実施例１】
芳香族ジアミンとして、４，４’−ジアミノジフェニルエーテルを、芳香族テトラカルボン酸二無水物としてピロメリット酸二無水物を用いて得られたポリアミド酸のＤＭＦ溶液に、ポリアミド酸の１繰り返し単位当たり分子量に対してイミド化剤として５．５モルの無水酢酸と０．５５モルのイソキノリンを添加して十分に攪拌し、約０℃の製膜用ドープ液として調整した。
【００９５】
上記得られたドープ液をＴダイより、平滑な金属製エンドレスベルト上に連続的に約２５０μm の厚さで流延塗布し、ベルトを回転させながら熱風乾燥した。この時、ベルト室の温度条件は、ベルト温度１２０℃×２分、冷却プーリーの温度８５℃とし、エンドレスベルトから剥がした。このゲルフィルムの残揮発物量は、３１％であった。
【００９６】
ついで、これらのフィルムをテンター室で、２００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μm のポリイミドフィルムの接着強度を測定した。接着強度は１４．８Ｎ／ｃｍであった。
【００９７】
【実施例２】
実施例１と同様にドープ液を調整した。得られたドープ液をＴダイより、平滑な金属製エンドレスベルト上に連続的に約２５０μm の厚さで流延塗布し、ベルトを回転させながら熱風乾燥した。この時、ベルト室の温度条件は、ベルト温度１０５℃×２分、冷却プーリーの温度８５℃とし、エンドレスベルトから剥がした。このゲルフィルムの残揮発物量は、６４％であった。
【００９８】
ついで、これらのフィルムをテンター室で、２００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μm のポリイミドフィルムの接着強度を測定した。接着強度は１４．９Ｎ／ｃｍであった。
【００９９】
【実施例３】
実施例１と同様にドープ液を調整した。得られたドープ液をＴダイより、平滑な金属製エンドレスベルト上に連続的に約２５０μm の厚さで流延塗布し、ベルトを回転させながら熱風乾燥した。この時、ベルト室の温度条件は、ベルト温度１００℃×２分、冷却プーリーの温度８５℃とし、エンドレスベルトから剥がした。このゲルフィルムの残揮発物量は、９７％であった。
【０１００】
ついで、これらのフィルムをテンター室で、２００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μm のポリイミドフィルムの接着強度を測定した。接着強度は１４．８Ｎ／ｃｍであった。
【０１０１】
【比較例１】
実施例１と同様にして、ゲルフィルムを得た。ついで、これらのフィルムをテンター室で、３００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μm のポリイミドフィルムの接着強度を測定した。接着強度は１２．９Ｎ／ｃｍであった。
【０１０２】
【比較例２】
実施例２と同様にして、ゲルフィルムを得た。ついで、これらのフィルムをテンター室で、３００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μm のポリイミドフィルムの接着強度を測定した。接着強度は１１．７Ｎ／ｃｍであった。
【０１０３】
【比較例３】
実施例３と同様にして、ゲルフィルムを得た。ついで、これらのフィルムをテンター室で、３００℃×３０秒、その後３５０〜５８０℃の範囲で徐々に昇温し、合計時間１２０秒の熱処理を行った。その後、冷却室で室温まで徐々に降温し、さらに所定のコロナ処理を行った。得られた２５μmのポリイミドフィルムの接着強度を測定した。接着強度は９．８Ｎ／ｃｍであった。
【０１０４】
結果を表１にまとめた。
【０１０５】
【表１】

【０１０６】
【発明の効果】
以上のようにして得られたポリイミドフィルムは、テンター室の初期設定温度を制御することにより、顕著な接着性向上の効果を得ることが可能であり、複雑なゲルフィルムの条件設定や、フィルム製造後の後処理工程を省くことができる。
【０１０７】
【図面の説明】
【０１０８】
【図１】本発明にかかるポリイミドフィルムの製造装置の概略図である。
【０１０９】
【符号の説明】
１０；ベルト室
１２；T ダイ
１４；エンドレスベルト
１６；ゲルフィルム
１８；テンター室
２０；加熱炉
２２；徐冷炉
２４；ポリイミドフィルム
２６；冷却プーリー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for producing a polyimide film, and more particularly to a method and an apparatus for controlling heat treatment conditions in order to impart adhesion.
[0002]
[Prior art]
Polyimide is known to have excellent properties such as heat resistance, cold resistance, chemical resistance, electrical insulation, and mechanical strength. Electrical insulation film, heat insulation film, flexible printed wiring board base film Widely used. In particular, in applications such as flexible wiring boards and electrical insulation films, specifically, polyimide films are bonded to copper foil via an adhesive to form a laminated laminate, prepreg by adhesive coating, It is often used for applications such as compounding. Therefore, the adhesive ability of the film is an important characteristic, and various improvements in adhesiveness are achieved.
[0003]
By the way, techniques for imparting adhesiveness to a polymer film include, for example, flame treatment, corona treatment, ultraviolet treatment, alkali treatment, sand blast treatment, plasma treatment and the like as post-treatments after the production of a polyimide film. Also, in the gel film production stage, the gel film is imidated to increase the imidation rate, and the amount of residual volatiles in the film is limited to be small, and the adhesion is improved by obtaining a gel film that is relatively dry and undergoes an imidization reaction. A method has been developed.
[0004]
[Problems to be solved by the invention]
However, in the former method, the surface property improving treatment after the polyimide film is manufactured is intended to improve the adhesion ability by further post-treating the product film. Therefore, problems may arise in terms of fluctuations in the bonding ability of the product film before post-treatment, stability of the post-treatment, homogeneous production, etc., and it is fundamental to stably supply a film with improved adhesion ability. It was difficult. In addition, there is a problem in that a new process for performing the treatment for improving the adhesiveness is required for the commercialized film, and it is inevitable that the cost is increased in practice.
[0005]
In the latter method, it is necessary to considerably dry the gel film before the gel film is produced, and the running cost of the drying apparatus becomes high. Further, since the drying speed in the belt chamber needs to be advanced, the line speed of the entire manufacturing process is restricted, so that the production efficiency cannot be increased. Furthermore, since drying is performed quickly, leveling is difficult to occur and thickness unevenness is likely to occur. If the film is further dried, there are various problems such as the film floating from the belt and falling due to the weight of the film itself. .
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have come up with a polyimide film manufacturing method and apparatus that improve the adhesion by adjusting the heat treatment conditions of the gel film, and have completed the present invention. .
[0007]
The first aspect of the present invention is a method for producing a polyimide film in which a composition containing an organic solvent solution of a polyimide precursor material is cast-coated and heated to form a gel film, and then the gel film is further subjected to heat treatment. A method for producing a polyimide film, wherein the heat treatment is performed at an initial temperature of 150 ° C. or more and 250 ° C. or less and a maximum temperature of 500 ° C. or more and 630 ° C. or less . The second aspect of the present invention is a method for producing a polyimide film in which a composition containing an organic solvent solution of a polyimide precursor material is cast-coated and heated to form a gel film, and then the gel film is further subjected to heat treatment. A method for producing a polyimide film, wherein the heat treatment is performed at an initial temperature of 150 ° C. to 250 ° C. and a maximum temperature of 500 ° C. to 630 ° C. to form a polyimide film having a thickness of 25 μm or less .
[0008]
A third aspect of the present invention is a method for producing a polyimide film, wherein the heat treatment time is 1 minute to 5 minutes .
[0009]
A fourth aspect of the present invention is a polyimide film manufacturing apparatus comprising a belt chamber that is heated after casting a composition containing an organic solvent solution of a polyimide precursor material, and a tenter chamber that includes a heating furnace and a slow cooling furnace. wherein the heating furnace, the initial setting temperature 0.99 ° C. to 250 DEG ° C., that then have a temperature gradient within a temperature range of 300 ° C. ~ 630 ° C., comprising a plurality of furnace to a maximum temperature of 500 ° C. or higher 630 ° C. or less It is a manufacturing apparatus of a polyimide film. The fifth aspect of the present invention is a polyimide film manufacturing apparatus in which the heat treatment time in the heating furnace is 1 minute to 5 minutes .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, although the manufacturing method of the polyimide film concerning this invention and its apparatus are demonstrated based on one example of embodiment, this invention is not limited to these.
[0011]
In general, since a polyimide film is insoluble and infusible, a solvent cast method in which an organic solvent solution of the precursor material is cast on a support such as a drum or a belt is used. In the method for producing a polyimide film according to the present invention, Also use this method.
[0012]
Hereafter, the manufacturing method and apparatus of the polyimide film concerning this invention are demonstrated concretely.
[0013]
The polyimide film according to the present invention is obtained from various known raw materials and is not particularly limited. Mainly using organic tetracarboxylic dianhydride and organic diamine as raw materials, each component is substantially used. It is obtained by polymerization in an organic solvent solution using equimolar amounts.
[0014]
The polyimide film according to the present invention is a film made of polyimide in a broad sense, and examples thereof include polyimide, polyamideimide, polyetherimide, and polyesterimide, and are not particularly limited such as non-thermoplastic, thermoplastic, and thermosetting. . That is, the molecular structure of polyimide does not matter. For example, preferably, the following general structural formula (1)
[0015]
[Chemical 1]

[0016]
It is applied to a polyimide having a repeating unit of
[0017]
In the formula, R ₁ is a tetravalent organic group. Specifically, it has at least one aromatic group, and an adjacent carbonyl group to be bonded is formed by directly bonding an aromatic ring. More specifically,
[0018]
[Chemical formula 2]

[0019]
(In the formula, X is
[0020]
[Chemical 3]

[0021]
R ₄ is CH ₃ —, Cl—, Br—, F—, CH ₃ O—, and when two or more are substituted, R ₄ is the same. May be different. ) Is at least one selected from the group represented by:
[0022]
In the formula, R ₂ has a divalent organic group, specifically, at least one aromatic group, and more specifically,
[0023]
[Formula 4]

[0024]
(In the formula, R ₄ is CH ₃ —, Cl—, Br—, F—, CH ₃ O—, and when two or more are substituted, R ₄ may be the same or different. .) At least one selected from the group represented by:
[0025]
Particularly preferred polyimides are those in which R ₁ is
[0026]
[Chemical formula 5]

[0027]
Where R ₂ is
[0028]
[Chemical 6]

[0029]
In the formula, R ₁ is
[0030]
[Chemical 7]

[0031]
Where R ₂ is
[0032]
[Chemical 8]

[0033]
And
[0034]
[Chemical 9]

[0035]
It is applied to a polyimide copolymer each having a main component.
[0036]
More preferably,
[0037]
[Chemical Formula 10]

[0038]
And 11
[0039]
Embedded image

[0040]
The molar ratio of
[0041]
[Expression 1]

[0042]
Of the range. R ₁ is
[0043]
Embedded image

[0044]
Where R ₂ is
[0045]
Embedded image

[0046]
And R ₁ is
[0047]
Embedded image

[0048]
And
[0049]
Embedded image

[0050]
Where R ₂ is
[0051]
Embedded image

[0052]
And
[0053]
Embedded image

[0054]
It is applicable also to the polyimide copolymer which has as a main component.
[0055]
Hereinafter, the manufacturing method of a polyimide resin is demonstrated. The polyimide resin represented by the general formula (1) is obtained by dehydrating and ring-closing the precursor polyamic acid polymer, and this polyamic acid solution is prepared by a conventionally known method using acid dianhydride and diamine. It is obtained by polymerizing in an organic polar solvent using substantially equimolar amounts of the components.
[0056]
First, a method for producing a polyamic acid will be described. First, in an inert gas atmosphere such as argon or nitrogen, the general formula (2)
[0057]
Embedded image

[0058]
(Wherein R ₁ represents a tetravalent organic group), at least one acid dianhydride or more is dissolved in an organic solvent from the aromatic tetracarboxylic dianhydride represented by: Spread. In this solution, the general formula (3)
H ₂ N—R ₂ —NH ₂ (3)
(Wherein R ₂ represents a divalent organic group) At least one or more diamine components represented by the formula (1) are dissolved in an organic solvent, or are dispersed in a slurry state, or in a solid state Addition to obtain a polyamic acid polymer solution.
[0059]
The reaction temperature at this time is preferably -10 ° C to 50 ° C. The reaction time is about 30 minutes to 6 hours.
[0060]
In this reaction, contrary to the above addition order, first, the diamine component may be diffused or dissolved, and a solution or slurry of acid dianhydride solid or organic solvent may be added to the solution.
[0061]
In order to maintain the strength of the produced polyimide resin, the number average molecular weight is preferably 10,000 or more. The molecular weight of a polyimide polymer is often difficult to measure directly. In such a case, estimation is performed by an indirect method. For example, when the polyimide polymer is synthesized from polyamic acid, the value corresponding to the molecular weight of the polyamic acid is taken as the molecular weight of the polyimide.
[0062]
Further, the general formula (2)
[0063]
Embedded image

[0064]
As the aromatic tetracarboxylic dianhydride represented by general formula (2), various tetracarboxylic dianhydrides can be used essentially. More specifically, from the balance of various properties, the general formula (2) R ₁ inside is
[0065]
Embedded image

[0066]
Wherein X is
[0067]
Embedded image

[0068]
It is a bivalent functional group represented by these. In the formula, R ₄ is CH ₃ —, Cl—, Br—, F—, CH ₃ O—, and when two or more are substituted, R ₄ may be the same or different. . 1 or more types of aromatic tetracarboxylic dianhydrides showing a tetravalent organic group represented by formula (1) can be selected.
[0069]
As the diamine compound represented by the general formula (3), various diamines can be used essentially. More specifically, from the balance of various properties, the general formula (3)
H ₂ N—R ₂ —NH ₂ (3)
R ₂ inside is
[0070]
Embedded image

[0071]
(In the formula, R ₄ is CH ₃ —, Cl—, Br—, F—, CH ₃ O—, and when two or more are substituted, R ₄ may be the same or different. It is possible to select one or more diamines which are divalent organic groups represented by:
[0072]
Furthermore, examples of the organic solvent that can be used in the present invention include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and N, N-dimethyl. Acetamide solvents such as acetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m-, or p-cresol, xylenol, Phenolic solvents such as halogenated phenols and catechols, hexamethylphosphoramide, γ-butyrolactone, and the like can be mentioned. These are preferably used alone or as a mixture, but more preferably aromatic such as xylene and toluene. Some hydrocarbons Use is also possible.
[0073]
In addition, when preparing the polyamic acid solution, or after preparing the polyamic acid solution, or as a dehydrating agent and catalyst by a chemical method, an antioxidant, a light stabilizer, a flame retardant, an antistatic agent, a heat stabilizer, UV absorption An agent, inorganic fillers, other reinforcing agents, or the like can be mixed.
[0074]
In addition, a method for producing polyimide is a chemical in which a polyamic acid which is a precursor is reacted with a dehydrating ring-closing agent represented by an acid anhydride such as acetic anhydride and a tertiary amine such as picoline, quinoline, isoquinoline or pyridine. A method of converting to polyimide by a curing method and a so-called thermal curing method in which an imidization reaction proceeds only by heating without causing the dehydrating agent or the like to act can also be used. Furthermore, a method using both in combination can also be used.
[0075]
When the chemical curing method and the thermal curing method are combined, usually the chemical curing method is mainly performed in the first half of the process, and then the imidization is completed by the thermal curing method in the second half.
[0076]
Here, the “gel film” in the present invention is defined as a film at a stage where the first half of the chemical curing process is completed, or a film before entering the thermal curing process by the thermal curing method.
[0077]
The manufacturing equipment for imidizing the polyimide precursor and finally making it a polyimide film product is largely divided into a drum chamber or belt chamber having a heating means for casting and chemical curing, and a tenter chamber for performing thermal curing. Divided.
[0078]
FIG. 1 shows an example of a production process of a polyimide film according to the present invention. First, the process in the belt chamber 10 is a process in which a polyimide precursor mixed by a mixer is extruded into a film shape by a T-die 12 and is reactively cured. In the chamber, a film-like polyimide precursor extruded from a T-die is formed in a film form on an endless belt or casting drum 14. The precursor formed in the form of a film is imidized by being heated by a heating means while being moved by the rotation of a belt or a drum. In this belt chamber, products generated by the reaction, mainly combustible volatile components such as acetic acid and organic solvents evaporate.
[0079]
The heating means in the belt chamber 10 is used to prevent the danger of flammable combustible volatile components evaporated from the resin or to prevent the resin itself from igniting, and the ambient temperature and the rotation speed of the belt or drum. For example, warm air, hot air, radiant heat, belt heating or the like can be used. The temperature conditions in the belt chamber are exemplified. The belt 1 chamber is 100 ° C., the belt 2 chamber 120 ° C., the belt 3 chamber 130 ° C., and the cooling pulley 26 is self-supported by the cast film under the temperature conditions such as 80 ° C. Sex is imparted.
[0080]
Through these steps, while the polyimide precursor film is imidized, the film is heated and dried to the extent that the film has self-supporting properties, and then peeled off from the endless belt or casting drum to obtain the gel film 16 referred to in the present invention. obtain.
[0081]
The gel film 16 is fixed at the end and is heat-treated in the tenter chamber 18. For example, the tenter chamber 18 includes a heating furnace 20 and a slow cooling furnace 22, and in FIG. 1, the film moves in the tenter chamber by moving a pin sheet having a film fixed with pins by rotational driving of a pin conveyor. The gel film is further imidized by gradually heating in a heating furnace 20 that performs thermal curing.
[0082]
As the heating furnace 20, for example, a hot air furnace or a far infrared heater can be used.
[0083]
In the heating furnace 20, the temperature is gradually raised to complete imidization into polyimide.
[0084]
The temperature of the heat treatment varies depending on the initial set temperature, the film thickness, the type of organic solvent used for the reaction of the polyimide precursor, and the like. Specifically, for example, the initial set temperature is preferably 200 ° C. to 250 ° C. for a film having a final film thickness of 25 μm, and 150 ° C. to 200 ° C. for a film having a final film thickness of 125 μm. At this stage, it is considered that the gel film is effectively dried and the imidization reaction proceeds at the same time.
[0085]
After that, it is preferable to gradually heat to a maximum temperature of 500 ° C. or more and 630 ° C. or less. More preferably, a range of 540 ° C. or higher and 580 ° C. or lower is preferable. The temperature gradient reaching the maximum temperature is not particularly limited as long as the heat treatment is performed in the above temperature range. The heat treatment time is several seconds to several tens of minutes, preferably 1 minute to 5 minutes, and is appropriately set in relation to the heat treatment temperature.
[0086]
The temperature gradient is set according to the state of the film such as the film thickness and the degree of drying, and is not particularly limited. Specifically, in the case of a film having a film thickness of 25 μm, it is 30 seconds at a temperature range of 200 ° C. to 250 ° C., 30 seconds at a temperature range of 300 ° C. to 350 ° C., and 400 ° C. to 450 ° C. 30 seconds in the following temperature range, and 60 seconds in the temperature range from 500 ° C. to 580 ° C.
[0087]
In the heat curing step in the heating furnace 20, the completely imidized polyimide film is gradually cooled in the cooling furnace 22.
[0088]
The polyimide film obtained by the production method according to the present invention means a broadly defined film including a sheet-like material having a thickness of several μm to several hundred μm, and the thickness can be selected according to the application. For example, when used as a base film of a flexible printed wiring board, a film of about 12.5 μm to 50 μm can be applied. In particular, in the case of a polyimide film having a film thickness of 25 μm or less, by setting the initial temperature setting of the heating furnace to 150 ° C. to 250 ° C., a remarkable effect can be exhibited in improving the adhesiveness.
[0089]
As described above, the produced polyimide film contains a large amount of organic solvent solution at the gel film stage, and the low degree of imidization rate also determines the degree of film drying and imidization rate at the gel film stage. A significant improvement in adhesion was observed at the polyimide film stage of the product without being strictly limited and without post-treatment of the product. Therefore, the polyimide film production method according to the present invention is an epoch-making polyimide film production method and production apparatus capable of omitting the complicated dryness management step at the gel film stage in the film production process, This can effectively contribute to the improvement of the adhesive strength of the final polyimide film.
[0090]
As mentioned above, although the example of embodiment of the manufacturing method of the polyimide film concerning this invention was demonstrated, this invention is not limited only to these embodiment, The knowledge of those skilled in the art within the range which does not deviate from the meaning of this invention. Based on the above, the present invention can be implemented in a mode with various improvements, changes and modifications.
[0091]
【Example】
Hereinafter, an Example is shown concretely about the manufacturing method of the polyimide film concerning this invention. The present invention is not limited to these examples.
[0092]
In addition, in the Example, the measuring method of the adhesive strength measured was evaluated with the following method. A film and a copper foil (electrolytic copper foil manufactured by Mitsui Mining & Smelting Co., Ltd .; 3BC 35 μm thickness) are laminated using an acrylic adhesive (manufactured by DuPont Co., Ltd .; Pyrax), and the adhesive is 185 ° C. × 1 hour. The sample was cut out so that the copper pattern width of FCCL was 3 mm, and a 90 ° peel test was performed at a peel test speed of 50 mm / min using a tensile tester (manufactured by Shimadzu Corporation; S-100-C). Went. The measurement results by the average value of n = 5 are shown in the table.
[0093]
In the examples, the corona treatment applied to the polyimide film was performed using an aluminum electrode at a power density of 220 ± 10 W · min / m ² .
[0094]
[Example 1]
The molecular weight per repeating unit of polyamic acid was added to a DMF solution of polyamic acid obtained using 4,4′-diaminodiphenyl ether as aromatic diamine and pyromellitic dianhydride as aromatic tetracarboxylic dianhydride. As an imidizing agent, 5.5 mol of acetic anhydride and 0.55 mol of isoquinoline were added and stirred sufficiently to prepare a dope solution for film formation at about 0 ° C.
[0095]
The obtained dope solution was continuously cast from a T die onto a smooth metal endless belt at a thickness of about 250 μm, and dried with hot air while rotating the belt. At this time, the temperature conditions of the belt chamber were a belt temperature of 120 ° C. × 2 minutes and a cooling pulley temperature of 85 ° C., and the belt chamber was peeled off from the endless belt. The residual volatile content of this gel film was 31%.
[0096]
Subsequently, these films were gradually heated in a tenter chamber at 200 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 14.8 N / cm.
[0097]
[Example 2]
A dope solution was prepared in the same manner as in Example 1. The obtained dope solution was continuously cast from a T die onto a smooth metal endless belt at a thickness of about 250 μm, and dried with hot air while rotating the belt. At this time, the temperature conditions of the belt chamber were a belt temperature of 105 ° C. × 2 minutes and a cooling pulley temperature of 85 ° C., and the belt chamber was peeled off from the endless belt. The residual volatile content of this gel film was 64%.
[0098]
Subsequently, these films were gradually heated in a tenter chamber at 200 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 14.9 N / cm.
[0099]
[Example 3]
A dope solution was prepared in the same manner as in Example 1. The obtained dope solution was continuously cast from a T die onto a smooth metal endless belt at a thickness of about 250 μm, and dried with hot air while rotating the belt. At this time, the temperature conditions of the belt chamber were a belt temperature of 100 ° C. × 2 minutes, a cooling pulley temperature of 85 ° C., and the belt chamber was peeled off from the endless belt. The residual volatile content of this gel film was 97%.
[0100]
Subsequently, these films were gradually heated in a tenter chamber at 200 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 14.8 N / cm.
[0101]
[Comparative Example 1]
A gel film was obtained in the same manner as Example 1. Subsequently, these films were gradually heated in a tenter chamber at 300 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 12.9 N / cm.
[0102]
[Comparative Example 2]
A gel film was obtained in the same manner as Example 2. Subsequently, these films were gradually heated in a tenter chamber at 300 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 11.7 N / cm.
[0103]
[Comparative Example 3]
A gel film was obtained in the same manner as in Example 3 . Subsequently, these films were gradually heated in a tenter chamber at 300 ° C. for 30 seconds and then in the range of 350 to 580 ° C., and subjected to heat treatment for a total time of 120 seconds. Thereafter, the temperature was gradually lowered to room temperature in the cooling chamber, and a predetermined corona treatment was further performed. The adhesive strength of the obtained 25 μm polyimide film was measured. The adhesive strength was 9.8 N / cm.
[0104]
The results are summarized in Table 1.
[0105]
[Table 1]

[0106]
【The invention's effect】
The polyimide film obtained as described above can obtain the effect of remarkable adhesion improvement by controlling the initial setting temperature of the tenter chamber. Subsequent post-processing steps can be omitted.
[0107]
[Explanation of drawings]
[0108]
FIG. 1 is a schematic view of an apparatus for producing a polyimide film according to the present invention.
[0109]
[Explanation of symbols]
10; belt chamber 12; T die 14; endless belt 16; gel film 18; tenter chamber 20; heating furnace 22; slow cooling furnace 24; polyimide film 26;

Claims (5)

In the method for producing a polyimide film, a composition containing an organic solvent solution of a polyimide precursor material is casted and then heated to form a gel film, and then the gel film is further subjected to heat treatment.
A method for producing a polyimide film, wherein the heat treatment is performed at an initial temperature of 150 ° C. to 250 ° C. and a maximum temperature of 500 ° C. to 630 ° C. In the method for producing a polyimide film, a composition containing an organic solvent solution of a polyimide precursor material is casted and then heated to form a gel film, and then the gel film is further subjected to heat treatment.
A method for producing a polyimide film, wherein the heat treatment is performed at an initial temperature of 150 ° C. to 250 ° C. and a maximum temperature of 500 ° C. to 630 ° C. to form a polyimide film having a thickness of 25 μm or less. The method for producing a polyimide film according to claim 1 or 2, wherein the heat treatment time is 1 minute to 5 minutes . In a polyimide film manufacturing apparatus composed of a belt chamber that heats a composition containing an organic solvent solution of a polyimide precursor material after casting and a tenter chamber composed of a heating furnace and a slow cooling furnace, the heating furnace is initially set. temperature 0.99 ° C. to 250 DEG ° C., then have a temperature gradient within a temperature range of 300 ℃ ~ 630 ℃, apparatus for producing a polyimide film characterized by comprising a plurality of furnace to a maximum temperature of 500 ° C. or higher 630 ° C. or less . The apparatus for producing a polyimide film according to claim 4, wherein a heat treatment time in the heating furnace is 1 minute to 5 minutes .

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