JP2004230670A

JP2004230670A - Thermally fusible polyimide films, laminated sheet using polyimide film and method for manufacturing polyimide film/laminated sheet

Info

Publication number: JP2004230670A
Application number: JP2003020942A
Authority: JP
Inventors: Toshihiko Abu; 俊彦阿武; Hideki Iwai; 英記岩井; Hiroto Shimokawa; 裕人下川; Toshiyuki Nishino; 敏之西野
Original assignee: Ube Industries Ltd
Current assignee: Ube Corp
Priority date: 2003-01-29
Filing date: 2003-01-29
Publication date: 2004-08-19
Anticipated expiration: 2023-01-29
Also published as: JP3938058B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermally fusible polyimide film with high heat resistance which is used for manufacturing a one side metallic foil laminated sheet, especially a one side copper-plated laminated sheet, both not using a release paper during laminating a metallic foil, and a one side metallic foil laminated sheet, especially a one side copper-plated laminated sheet, both using the polyimide film. <P>SOLUTION: This polyimide film has a thermally fusible polyimide layer with a thickness of 4 to 45 μm formed on both surfaces of a heat-resistant polyimide layer (an S1 layer) with almost the same thickness as the former and a total thickness of 3 to 10 μm of the thickness of the thermally fusible polyimide layer formed on one surface of the heat-resistant polyimide layer (the S1 layer) and the thickness of the thermally fusible polyimide layer formed on the other surface. In addition, the 0.1 to 2 μm thick heat-resistant polyimide layer (an S2 layer) without heat fusibility is laminated on the thermally-fusible polyimide layer one surface of the heat-resistant polyimide layer (the S1 layer), so that the polyimide film has heat fusibility only on one surface. Thus the polyimide film having the heat fusibility on one surface and a copper foil are laminated over each other by thermal contact bonding through the polyimide layer with the heat fusibility. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、片面のみに熱融着性を有する多層ポリイミドフィルム、片面金属箔積層板およびそれらの製造法に関するものであり、さらに詳しくは耐熱性ポリイミド層の両面に熱融着性ポリイミド層を有しさらに片面に熱融着性を有しない耐熱性ポリイミド層が積層されてなる４層構造を有する片面のみに熱融着性を有するポリイミドフィルム、該ポリイミドフィルムを用いた片面金属箔積層板及びそれらの製造法に関するものである。
この発明によれば、電子部品の実装工程で装置に張り付くことが実質的になく成形加工性が良好なオ−ルポリイミドの片面銅張板を与える熱融着性を有する多層ポリイミドフィルムおよび片面銅張り積層板を得ることができる。
【０００２】
【従来の技術】
カメラ、パソコン、液晶ディスプレイなどの電子機器類への用途として芳香族ポリイミドフィルムは広く使用されている。
芳香族ポリイミドフィルムをフレキシブルプリント板（ＦＰＣ）やテ−プ・オ−トメイティッド・ボンディング（ＴＡＢ）などの基板材料として使用するためには、エポキシ樹脂などの接着剤を用いて銅箔を張り合わせる方法が採用されている。
【０００３】
芳香族ポリイミドフィルムは耐熱性、機械的強度、電気的特性などが優れているが、エポキシ樹脂などの接着剤の耐熱性等が劣るため、本来のポリイミドの特性を損なうことが指摘されている。
このような問題を解決するために、接着剤を使用しないでポリイミドフィルムに銅を電気メッキしたり、銅箔にポリアミック酸溶液を塗布し、乾燥、イミド化したり、熱可塑性のポリイミドを熱圧着させたオ−ルポリイミド基材も開発されている。
【０００４】
また、ポリイミドフィルムと金属箔との間にフィルム状ポリイミド接着剤をサンドイッチ状に接合させたポリイミドラミネ−トおよびその製法が知られている（特許文献１）。
しかし、このポリイミドラミネ−トおよびその製法は、フィルム状ポリイミド接着剤の取り扱いが容易ではなく、しかもある種のポリイミドフィルムについては剥離強度（接着強度）が小さく適用できない。
【０００５】
さらに、金属箔積層ポリイミドフィルムおよびその製造法が知られている（特許文献２、特許文献３）。
しかし、これらの文献には、多層ポリイミドフィルムと金属箔とが強固に接着された積層体が記載されているに過ぎず、寸法安定性については未解決であった。
このため、ダブルベルトプレスによって３層構造の熱圧着性ポリイミドフィルムの両面に金属箔を積層した寸法安定性の良好なフレキシブル金属箔積層体が提案された（特許文献４）。
【０００６】
【特許文献１】
米国特許第４５４３２９５号公報
特開平８−２７６５４７号公報。
【特許文献２】
特開平４−３３８４７号公報
【特許文献３】
特開平４−３３８４８号公報
【特許文献４】
特開２０００−１０３０１０号公報
【０００７】
【発明が解決しようとする課題】
しかし、従来公知の技術によれば、片面金属箔積層板、例えば片面銅張り積層板においてカ−ル抑制の必要性から両面に熱融着性を有するポリイミドフィルムが必要であり、銅箔を張り合わせない面には離型紙として高耐熱性ポリイミドフィルムを用いることが必要であるが、使用時に離型紙を除く必要があり加工性が悪くなる。しかも、剥離紙を除いた片面銅張り積層板は、熱融着性を有するポリイミド層がむき出しとなるため、工程によっては電子部品の実装工程で装置に張り付くなどの問題がある。
従って、この発明の目的は、金属箔積層時に剥離紙を使用しないで片面金属箔積層板、特に片面銅張り積層板を製造できる高耐熱性の熱融着性ポリイミドフィルムおよび該ポリイミドフィルムを用いた片面金属箔積層板、特に片面銅張り積層板を提供することである。
【０００８】
【課題を解決するための手段】
この発明は、厚みが４〜４５μｍの耐熱性ポリイミド層（Ｓ１層）の両面に厚みが略等しい熱融着性ポリイミド層を有し、片面の熱融着性ポリイミド層の厚みと他面の熱融着性ポリイミド層の厚みとの合計が３〜１０μｍであり、該熱融着性ポリイミド層の片面に厚みが０．１〜２μｍの熱融着性を有しない耐熱性ポリイミド層（Ｓ２層）が積層されてなる片面のみに熱融着性を有するポリイミドフィルムに関する。
また、この発明は、前記の片面のみに熱融着性を有するポリイミドフィルムと銅箔とが、熱融着性を有するポリイミド層を介して熱圧着によって積層されている片面金属箔積層板に関する。
【０００９】
また、この発明は、耐熱性ポリイミドを与えるポリアミック酸溶液とその両側に熱融着性ポリイミドを与えるポリアミック酸溶液とを、耐熱性ポリイミド層（Ｓ１層）の厚みが４〜４５μｍで、両側の熱融着性ポリイミド層の厚みの合計が３〜１０μｍとなるように積層し、自己支持性を示すまで加熱乾燥した自己支持性フィルムの片面に、熱融着性を有しない耐熱性ポリイミド層（Ｓ２層）を与える組成のポリアミック酸溶液を該耐熱性ポリイミド層（Ｓ２層）厚みが０．１〜２μｍとなるように塗布し、加熱して乾燥、イミド化する片面のみに熱融着性を有するポリイミドフィルムの製造法に関する。
【００１０】
さらに、この発明は、前記の片面のみに熱融着性を有するポリイミドフィルムおよび銅箔の各２組を、熱融着性を有しない耐熱性ポリイミド層を内側にし銅箔を外側にして、ダブルベルトプレスに連続的に供給し、２組を同時に加圧下に熱圧着および冷却した後、２組の積層体を引き剥がして別々に巻き取る長尺状の片面金属箔積層板の製造法に関する。
【００１１】
【発明の実施の形態】
以下にこの発明の好ましい態様を列記ずる。
１）片面の熱融着性ポリイミド層と他面の熱融着性ポリイミド層とが、その厚みの相違によって所望のカ−ル度に調整されてなる上記の片面のみに熱融着性を有するポリイミドフィルム。
２）熱融着性を有しない耐熱性ポリイミド層（Ｓ２層）が、耐熱性ポリイミド層（Ｓ１層）と同一モノマ−組成のポリイミドからなる上記の片面のみに熱融着性を有するポリイミドフィルム。
【００１２】
この発明においては、４〜４５ｍの基体層としての耐熱性ポリイミド層の両面に厚みが略等しい熱融着性ポリイミド層が積層され、片面の熱融着性ポリイミド層の厚みと他面の熱融着性ポリイミド層との合計の厚みが３〜１０μｍである。各熱圧着性ポリイミド層の厚みは好適には３〜４である。
また、この発明において、片面のみに熱融着性を有するポリイミドフィルムは、好適にはカ−ル度が＋Ｂ表示で０〜１０で、線膨張係数（５０〜２００℃）（ＭＤ）が１３〜３０×１０^−６ｃｍ／ｃｍ／℃である。
【００１３】
前記の基体層としての耐熱性ポリイミドは、好適には３，３’，４，４’−ビフェニルテトラカルボン酸二無水物（以下単にｓ−ＢＰＤＡと略記することもある。）とパラフェニレンジアミン（以下単にＰＰＤと略記することもある。）と場合によりさらに４，４’−ジアミノジフェニルエ−テル（以下単にＤＡＤＥと略記することもある。）とから製造される。この場合ＰＰＤ／ＤＡＤＥ（モル比）は１００／０〜８５／１５であることが好ましい。
また、基体層としての耐熱性ポリイミドは、３，３’，４，４’−ビフェニルテトラカルボン酸二無水物とピロメリット酸二無水物とパラフェニレンジアミンと４，４’−ジアミノジフェニルエ−テルとから製造される。この場合ＢＰＤＡ／ＰＭＤＡは１５／８５〜８５／１５で、ＰＰＤ／ＤＡＤＥは９０／１０〜１０／９０であることが好ましい。
【００１４】
また、基体層としての耐熱性ポリイミドは、ピロメリット酸二無水物とパラフェニレンジアミンおよび４，４’−ジアミノジフェニルエ−テルとから製造される。この場合ＤＡＤＥ／ＰＰＤは９０／１０〜１０／９０であることが好ましい。
さらに、基体層としての耐熱性ポリイミドは、３，３’，４，４’−ベンゾフェノンテトラカルボン酸二無水物（ＢＴＤＡ）およびピロメリット酸二無水物とパラフェニレンジアミンおよび４，４’−ジアミノジフェニルエ−テルとから製造される。この場合、酸二無水物中ＢＴＤＡ／ＰＭＤＡが２０／８０〜９０／１０、ジアミン中ＰＰＤ／ＤＡＤＥが３０／７０〜９０／１０であることが好ましい。
【００１５】
この発明における熱融着性を有しない耐熱性ポリイミドとしては、前記の基体層としての耐熱性ポリイミドを挙げることができる。
この発明において、前記の熱融着性を有しない耐熱性ポリイミドは基体層としての耐熱性ポリイミドと異なったポリイミド組成のものでもよいが、同一のポリイミド組成のものが好ましい。
【００１６】
上記の基体層としての耐熱性ポリイミドとしては、単独のポリイミドフィルムの場合にガラス転移温度が３００℃以上か確認不可能であるものが好ましく、特に線膨張係数（５０〜２００℃）（ＭＤ）が５×１０^−６〜２０×１０^−６ｃｍ／ｃｍ／℃であるものが好ましい。また、引張弾性率（ＭＤ、ＡＳＴＭ−Ｄ８８２）は３００ｋｇ／ｍｍ^２以上であるものが好ましい。
この基体層ポリイミドの合成は、最終的に各成分の割合が前記範囲内であればランダム重合、ブロック重合、あるいはあらかじめ２種類のポリアミック酸を合成しておき両ポリアミック酸溶液を混合後反応条件下で混合して均一溶液とする、いずれの方法によっても達成される。
【００１７】
前記各成分を使用し、ジアミン成分とテトラカルボン酸二無水物の略等モル量を、有機溶媒中で反応させてポリアミック酸の溶液（均一な溶液状態が保たれていれば一部がイミド化されていてもよい）とする。
前記基体層ポリイミドの物性を損なわない種類と量の他のテトラカルボン酸二無水物やジアミンを使用してもよい。
【００１８】
この発明における熱融着性ポリイミドとしては、種々の公知の熱可塑性ポリイミドから選択することができ、好適には１，３−ビス（４−アミノフェノキシベンゼン）（以下、ＴＰＥＲと略記することもある）と３，３’，４，４’−ビフェニルテトラカルボン酸二無水物および２，３，３’，４’−ビフェニルテトラカルボン酸二無水物（以下、ａ−ＢＰＤＡと略記することもある。）とから製造される。この場合ｓ−ＢＰＤＡ／ａ−ＢＰＤＡは１００／０〜５／９５であることが好ましい。
また、前記の熱融着性ポリイミドとして、１，３−ビス（４−アミノフェノキシ）−２，２−ジメチルプロパン（ＤＡＮＰＧ）と４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）およびａ−ＢＰＤＡとから製造される。
あるいは、４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）およびピロメリット酸二無水物と１，３−ビス（４−アミノフェノキシベンゼン）とから製造される。
【００１９】
前記の熱融着性ポリイミドは、前記各成分と、さらに場合により他のテトラカルボン酸二無水物および他のジアミンとを、有機溶媒中、約１００℃以下、特に２０〜６０℃の温度で反応させてポリアミック酸の溶液とし、このポリアミック酸の溶液をド−プ液として使用し、そのド−プ液の薄膜を形成し、その薄膜から溶媒を蒸発させ除去すると共にポリアミック酸をイミド環化することにより製造することができる。
また、前述のようにして製造したポリアミック酸の溶液を１５０〜２５０℃に加熱するか、またはイミド化剤を添加して１５０℃以下、特に１５〜５０℃の温度で反応させて、イミド環化した後溶媒を蒸発させる、もしくは貧溶媒中に析出させて粉末とした後、該粉末を有機溶液に溶解して熱圧着性ポリイミドの有機溶媒溶液を得ることができる。
【００２０】
この発明で熱融着性ポリイミドの物性を損なわない範囲で他のテトラカルボン酸二無水物、例えば３，３’，４，４’−ビフェニルテトラカルボン酸二無水物、２，２−ビス（３、４−ジカルボキシフェニル）プロパン二無水物あるいは２，３，６，７−ナフタレンテトラカルボン酸二無水物など、好適には３，３’，４，４’−ビフェニルテトラカルボン酸二無水物で置き換えられてもよい。
また、熱融着性ポリイミドの物性を損なわない範囲で他のジアミン、例えば４，４’−ジアミノジフェニルエ−テル、４，４’−ジアミノベンゾフェノン、４，４’−ジアミノジフェニルメタン、２，２−ビス（４−アミノフェニル）プロパン、１，４−ビス（４−アミノフェノキシ）ベンゼン、４，４’−ビス（４−アミノフェニル）ジフェニルエ−テル、４，４’−ビス（４−アミノフェニル）ジフェニルメタン、４，４’−ビス（４−アミノフェノキシ）ジフェニルエ−テル、４，４’−ビス（４−アミノフェノキシ）ジフェニルメタン、２，２−ビス〔４−（アミノフェノキシ）フェニル〕プロパンなどの複数のベンゼン環を有する柔軟な芳香族ジアミン、１，４−ジアミノブタン、１，６−ジアミノヘキサン、１，８−ジアミノオクタン、１，１０−ジアミノデカン、１，１２−ジアミノドデカンなどの脂肪族ジアミン、ビス（３−アミノプロピル）テトラメチルジシロキサンなどのジアミノジシロキサンによって置き換えられてもよい。他の芳香族ジアミンの使用割合は全ジアミンに対して２０モル％以下、特に１０モル％以下であることが好ましい。また、脂肪族ジアミンおよびジアミノジシロキサンの使用割合は全ジアミンに対して２０モル％以下であることが好ましい。この割合を越すと熱融着性ポリイミドの耐熱性が低下する。
前記の熱融着性ポリイミドのアミン末端を封止するためにジカルボン酸無水物、例えば、無水フタル酸およびその置換体、ヘキサヒドロ無水フタル酸およびその置換体、無水コハク酸およびその置換体など、特に、無水フタル酸を使用してもよい。
【００２１】
この発明における熱融着性ポリイミドを得るためには、前記の有機溶媒中、ジアミン（アミノ基のモル数として）の使用量が酸無水物の全モル数（テトラ酸二無水物とジカルボン酸無水物の酸無水物基としての総モルとして）に対する比として、０．９５〜１．０、特に０．９８〜１．０、そのなかでも特に０．９９〜１．０であることが好ましい。ジカルボン酸無水物を使用する場合の使用量は、テトラカルボン酸二無水物の酸無水物基モル量に対する比として、０．０５以下であるような割合の各成分を反応させることができる。
【００２２】
前記のジアミンおよびジカルボン酸無水物の使用割合が前記の範囲外であると、得られるポリアミック酸、従って熱圧着性ポリイミドの分子量が小さく、銅箔との積層体の接着強度の低下をもたらす。
また、ポリアミック酸のゲル化を制限する目的でリン系安定剤、例えば亜リン酸トリフェニル、リン酸トリフェニル等をポリアミック酸重合時に固形分（ポリマ−）濃度に対して０．０１〜１％の範囲で添加することができる。
また、イミド化促進の目的で、ド−プ液中に塩基性有機化合物を添加することができる。例えば、イミダゾ−ル、２−イミダゾ−ル、１，２−ジメチルイミダゾ−ル、２−フェニルイミダゾ−ル、ベンズイミダゾ−ル、イソキノリン、置換ピリジンなどをポリアミック酸に対して０．０５〜１０重量％、特に０．１〜２重量％の割合で使用することができる。これらは比較的低温でポリイミドフィルムを形成するため、イミド化が不十分となることを避けるために使用することができる。
また、接着強度の安定化の目的で、熱融着性ポリイミド用ポリアミック酸溶液に有機アルミニウム化合物、無機アルミニウム化合物または有機錫化合物を添加してもよい。例えば水酸化アルミニウム、アルミニウムトリアセチルアセトナ−トなどをポリアミック酸に対してアルミニウム金属として１ｐｐｍ以上、特に１〜１０００ｐｐｍの割合で添加することができる。
【００２３】
前記のポリアミック酸製造に使用する有機溶媒は、耐熱性ポリイミドおよび熱圧着性ポリイミドのいずれに対しても、Ｎ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド、ジメチルスルホキシド、ヘキサメチルホスホルアミド、Ｎ−メチルカプロラクタム、クレゾ−ル類などが挙げられる。これらの有機溶媒は単独で用いてもよく、２種以上を併用してもよい。
【００２４】
この発明の片面のみに熱融着性を有するポリイミドフィルムの製造においては、例えば上記の基体層の耐熱性ポリイミドを与えるポリアミック酸溶液と熱融着性ポリイミドを与えるポリアミック酸溶液を三層共押出法によって、耐熱性ポリイミド層の厚みが４〜４５μｍで両側の熱融着性ポリイミド層の厚みの合計が３〜１０μｍとなるように三層押出し成形用ダイスに供給し、支持体上にキャストしてこれをステンレス鏡面、ベルト面等の支持体面上に流延塗布し、１００〜２００℃で半硬化状態またはそれ以前の乾燥状態とすることが好ましい。
２００℃を越えた高い温度で流延フィルムを処理すると、熱融着性を有するポリイミドフィルムの製造において、接着性の低下などの欠陥を来す傾向にある。この半硬化状態またはそれ以前の状態とは、加熱および／または化学イミド化によって自己支持性の状態にあることを意味する。
【００２５】
次いで、加熱乾燥した自己支持性フィルムの片面（Ａ面あるいはＢ面）に、熱融着性を有しない耐熱性ポリイミド層を与える組成のポリアミック酸溶液を該耐熱性ポリイミド層の厚みが０．１〜２μｍとなるように、グラビア−ト法、スクリ−ン法、浸漬法などの塗布法で均一に塗布して均一に分布させ、その塗布フィルムを好ましくは５０〜１８０℃、特に好ましくは６０〜１６０℃、さらに好ましくは７０〜１５０℃の乾燥温度で好ましくは０．１〜２０分間、特に好ましくは０．２〜１５分間乾燥して固化フィルムを形成し、次いで、好ましくは（１）１００ｇｆ／ｍｍ^２以下、特に好ましくは８０ｇｆ／ｍｍ^２以下である実質的にフリ−の状態ないしは低張力下、および好ましくは（２）約８０〜２５０℃、特に好ましくは１００〜２３０℃の乾燥温度で、好ましくは約１〜２００分間、特に好ましくは２〜１００分間乾燥して、前記有機溶媒および生成水分が約５〜２５重量％、特に１０〜２３重量％の割合で含有されている固化フィルムを形成することが望ましい。
【００２６】
前記溶媒および生成水分が好ましくは約２５〜６０重量％、特に好ましくは３０〜５０重量％残存している固化フィルムを乾燥温度に昇温する際には、比較的短時間内に昇温することが好ましく、例えば、１０℃／分以上の昇温速度であることが好適である。乾燥する際に固化フィルム状体に対して加えられる張力を増大することによって、最終的に得られるポリイミドフィルムの線膨張係数を小さくすることができる。
そして、前述の乾燥工程に続いて、連続的または断続的に前記固化フィルムの少なくとも一対の両端縁を連続的または断続的に前記フィルムと共に移動可能な固定装置などで固定した状態で、前記の乾燥温度より高く、しかも好ましくは２００〜５５０℃の範囲内、特に好ましくは３００〜５００℃の範囲内の高温度で、好ましくは１〜１００分間、特に１〜１０分間、前記固化フィルムを乾燥および熱処理して、好ましくは最終的に得られるポリイミドフィルム中の有機溶媒および生成水等からなる揮発物の含有量が１重量％以下になるように、固化フィルムから溶媒などを充分に除去するとともに前記フィルムを構成しているポリマ−のイミド化を充分に行って、片面（Ｂ面あるいはＡ面）のみに熱融着性を有する多層ポリイミドフィルムを形成する。
【００２７】
前記の固化フィルムの固定装置としては、例えば、多数のピンまたは把持具などを等間隔で備えたベルト状またはチェ−ン状のものを、連続的または断続的に供給される前記固化フィルムの長手方向の両側縁に沿って一対設置し、そのフィルムの移動と共に連続的または断続的に移動させながら前記フィルムを固定できる装置が好適である。また、前記の固化フィルムの固定装置は、熱処理中のフィルムを幅方向または長手方向に適当な伸び率または収縮率（特に好ましくは０．５〜５％程度の伸縮倍率）で伸縮することができる装置であってもよい。
【００２８】
なお、前記の工程において製造された改質されたポリイミドフィルムを、再び好ましくは４００ｇｆ／ｍｍ^２以下、特に好ましくは３００ｇｆ／ｍｍ^２以下の低張力下あるいは無張力下に、１００〜４００℃の温度で、好ましくは０．１〜３０分間熱処理すると、特に寸法安定性が優れた片面（Ｂ面）のみに熱融着性を有する多層ポリイミドフィルムとすることができる。また、製造された長尺の片面のみに熱融着性を有する多層ポリイミドフィルムは、適当な公知の方法でロ−ル状に巻き取ることができる。
この発明の片面のみに熱融着性を有する多層ポリイミドフィルムは、線膨張係数（５０〜２００℃）（ＭＤ）が１３〜３０ｐｐｍ／℃で、カ−ルをユ−ザ−ニ−ズに合わせてＢ面＋表示で１０〜−１０（Ａ面＋１０）に調整可能であり、好適にはＢ面＋表示で０〜１０である。
【００２９】
この発明の片面のみに熱融着性を有する多層ポリイミドフィルムを用いてカ−ル度を調整する方法を以下に説明する。線膨張係数が１８ｐｐｍ／℃程度の場合、耐熱性ポリイミド層の厚みを例えば１５μｍとし、熱融着性を有さない耐熱性ポリイミド層の厚みを例えば１μｍとし、熱融着性ポリイミド層の厚みを例えばＡ面側３．０〜４．０μｍ、Ｂ面側２．５〜３．５μｍで変化させて、カ−ル度（Ｂ面＋１０〜Ｂ面−１５）を縦軸とし熱融着性ポリイミド層の厚み差（Ａ−Ｂ＝０〜１．５を横軸とし、各点をプロットする。その結果、カ−ル度（Ｂ面＋１０〜Ｂ面−）と熱融着性ポリイミド層の厚み差との間には直線が引ける。この直線から、あるカ−ル度に対応する熱融着性ポリイミド層の厚み差が得られる。
金属箔と積層する場合に、カ−ル度が例えばＢ面＋３〜＋５が好ましいとすると、それに対応した熱融着性ポリイミド層の厚み差を採用することによって望ましいカ−ル度が調整できるのである。
【００３０】
この発明において使用される金属箔（回路用）としては、銅、アルミニウム、金、合金の箔など各種金属箔が挙げられるが、好適には圧延銅箔、電解銅箔などの銅箔があげられる。
前記金属箔として、表面粗さＲｚが０．５μｍ以上であるものが好ましい。また、金属箔の表面粗さＲｚが７μｍ以下、特に５μｍ以下であるものが好ましい。このような金属箔、例えば銅箔はＶＬＰ、ＬＰ（またはＨＴＥ）として知られている。
金属箔の厚さは特に制限はないが、２〜３５μｍ、特に５〜１８μｍであるものが好ましい。
金属箔の厚みが５μｍ以下のものは、キャリア付き金属箔、例えばアルミニウム箔キャリア付き銅箔が使用される。
【００３１】
この発明においては、例えば前記の片面（Ｂ面）のみに熱融着性を有するポリイミドフィルムおよび金属箔を、少なくとも一対の加圧部材で連続的に、加圧部の温度が熱圧着性ポリイミドのガラス転移温度より３０℃以上で４２０℃以下の温度で加熱下に熱圧着して、長尺状の片面金属箔積層板を得ることができる。
前記の加圧部材としては、一対の圧着金属ロ−ル（圧着部は金属製、セラミック溶射金属製のいずれでもよい）またはダブルベルトプレスが挙げられ、特に加圧下に熱圧着および冷却できるものであって、そのなかでも特に液圧式のダブルベルトプレスを好適に挙げることができる。
この発明においては、前記の加圧部材、例えば金属ロ−ル、好適にはダブルベルトプレスを使用し、前記の多層ポリイミドフィルムと金属箔と補強材とを重ね合わせて、連続的に加熱下に圧着して、ポリイミド片面積層体を製造することができる。
【００３２】
また、片面のみに熱融着性を有するポリイミドフィルムおよび金属箔が、ロ−ル巻きの状態で加圧部材にそれぞれ供給され、ポリイミド片面積層体をロ−ル巻きの状態で得られる場合に特に好適である。
この発明の方法において、特に、前記の片面のみに熱融着性を有するポリイミドフィルムおよび金属箔各２組を、熱融着性を有しない耐熱性ポリイミド層面（Ａ面）を内側にし金属箔を外側にして、ダブルベルトプレスに連続的に供給し、２組を同時に加圧部の温度が熱融着性ポリイミドのガラス転移温度より３０℃以上で４２０℃以下の温度で加熱下に熱圧着および冷却した後、２組の積層体を引き剥がして別々に巻き取ることによって、長尺状の片面金属箔積層板を得ることが生産性の点からは好ましい。
【００３３】
この発明の片面金属箔積層板は、熱融着性を有する多層ポリイミドフィルムおよび金属箔が強固に、好適には９０°剥離強度が１．０ｋｇｆ／ｃｍ以上で積層されており、セラミック、耐熱性ポリイミドフィルム、金属などの他の基材と常温だけでなく３００℃程度の加熱時においても接着することがなく、例えば他の耐熱性ポリイミドフィルムと３００℃程度の温度で加圧下に積層しても９０°剥離強度が２０ｇｆ／ｃｍ以下である。
また、この発明の片面金属箔積層板は、好適には多層ポリイミドフィルムの線膨張係数（５０〜２００℃）（ＭＤ）が１３〜３０×１０^−６ｃｍ／ｃｍ／℃である。
この発明の片面金属箔積層板は、成形加工性が良好で、そのまま穴あけ加工、折り曲げ加工や絞り加工、金属配線形成、配線上への電子回路の熱圧着などを行うことができる。
【００３４】
【実施例】
以下、この発明を実施例および比較例によりさらに詳細に説明する。
以下の各例において、部は質量部を意味する。
以下の各例において、物性評価および銅箔積層フィルムの剥離強度は以下の方法に従って測定した。
線膨張係数：２０〜２００℃、５℃／分の昇温速度で測定（ＭＤ）した。
積層体の剥離強度：ＩＰＣ−ＦＣ−２４１３Ｂに従って、９０°剥離強度を測定した。
【００３５】
参考例１
基体層ポリイミド製造用ド−プの合成例１
攪拌機、窒素導入管を備えた反応容器に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を加え、さらに、パラフェニレンジアミン（ＰＰＤ）と３，３’，４，４’−ビフェニルテトラカルボン酸二無水物（ｓ−ＢＰＤＡ）とを１０００：９９８のモル比でモノマ−濃度が１８％（重量％、以下同じ）になるように加えた。添加終了後５０℃を保ったまま３時間反応を続けた。得られたポリアミック酸溶液は褐色粘調液体であり、２５℃における溶液粘度は約１５００ポイズであった。この溶液を基材用ド−プとして使用した。
【００３６】
熱融着性ポリイミド製造用ド−プの合成例１
攪拌機、窒素導入管を備えた反応容器に、ＮＭＰを加え、さらに、２，３，３’，４’−ビフェニルテトラカルボン酸二無水物、ｓ−ＢＰＤＡ、１，３−ビス（４−アミノフェノキシ）ベンゼンおよびＤＡＤＥを２０：８０：５０：５０のモル比でモノマ−濃度が２２％になるように、またトリフェニルホスフェ−トをモノマ−重量に対して０．１％加えた。添加終了後２５℃を保ったまま１時間反応を続けた。このポリアミック酸溶液は、２５℃における溶液粘度が約２０００ポイズであった。この溶液をド−プとして使用した。
【００３７】
耐熱性ポリイミド層塗工液の合成例１
Ｎ−メチル−２−ピロリドンに、ＰＰＤおよびｓ−ＢＰＤＡを１００：９６のモル比でモノマ−濃度が１８％（重量％、以下同じ）になるように加えてポリアミック酸溶液を得た後、酸／ジアミンが等モルとなるように３，３’，４，４’−ビフェニルテトラカルボン酸（ｓ−ＢＰＴＡ）を添加して原液を調合し、ＮＭＰで希釈し、モノマ−濃度が５％のポリアミック酸溶液を得た。この溶液を塗工用ド−プとして使用した。
【００３８】
実施例１
前記の基体層ポリイミド製造用ド−プと熱融着性ポリイミド製造用ド−プとを三層押出し成形用ダイス（マルチマニホ−ルド型ダイス）を設けた製膜装置を使用し、三層押出ダイスから金属製支持体上に流延し、１３０℃の熱風で連続的に乾燥した後剥離して自己支持性フィルムを形成し、この自己支持性フィルムの片面（Ａ面）に耐熱性ポリイミド層塗工用ド−プをグラビアコ−タ−にて塗工し、加熱炉で１５０℃から４５０℃まで徐々に昇温して溶媒の除去、イミド化を行い、長尺状の片面に厚みが１μｍの熱融着性を有しない耐熱性ポリイミド層が積層された片面のみに熱融着性を有するポリイミドフィルムを巻き取りロ−ルに巻き取った。
得られた片面のみに熱融着性を有するポリイミドフィルムは、各層の厚みが１μｍ／３．５μｍ／１７．２μｍ／３．３μｍ（合計２５μｍ）であり、カ−ル度がＢ＋８で、線膨張係数（５０−２００℃）が、ＭＤ：１８ｐｐｍ／℃、ＴＤ：１６ｐｐｍ／℃、平均：１７ｐｐｍ／℃であり、引張弾性率が７００ｋｇｆ／ｍｍ^２で、基体層ポリイミドのガラス転移温度は４００℃以下の温度で確認されず、熱融着層ポリイミドはガラス転移温度が２４２℃であり、ゲル化が実質的に生じていなかった。
【００３９】
実施例２
ダブルベルトプレスに、片面のみに熱融着性を有するポリイミドフィルムを約１５０℃に予熱して連続的に供給し、その両側からロ−ル巻きした電解銅箔（福田金属箔粉工業株式会社製、ＣＦ−Ｔ９、ＶＰ、Ｒｚが５μｍ、厚さ１８μｍ）金属箔各２組を、熱融着性を有しない耐熱性ポリイミド層面（Ａ面）を内側にして、加熱ゾ−ンの温度（最高加熱温度）３８０℃、冷却ゾ−ンの温度（最低冷却温度）１１７℃で、連続的に加圧下に熱圧着−冷却し、２組の片面銅張積層板を引き剥がして、片面積層板を巻き取りロ−ルに巻き取った。
得られた片面積層板の銅箔側の剥離強度は１．１ｋｇｆ／ｃｍであった。
また、別途に２組の片面銅張積層板の熱融着性を有しない耐熱性ポリイミド層間の９０°剥離強度を測定したところ、１３ｇｆ／ｃｍであった。
【００４０】
実施例３
実施例１とは別に製造した耐熱性ポリイミドフィルムおよび熱融着性ポリイミドフィルムから、耐熱性ポリイミドフィルムの線膨張係数：１２ｐｐｍ／℃を用いて、両層の厚みを換算して線膨張係数（ＭＤ、ＴＤの平均値）が１７ｐｐｍ／℃の片面のみに熱融着性を有するポリイミドフィルムを得ることとした。
実施例１において、耐熱性ポリイミド層の厚みを１７．４μｍとし、熱融着性を有さない耐熱性ポリイミド層の厚みを１μｍとし、熱融着性ポリイミド層の厚みを例えばＡ面側３．０〜４．０μｍ、Ｂ面側２．５〜３．５μｍで変化させて、種々の熱融着性ポリイミド層の厚み差を有する片面のみに熱融着性を有するポリイミドフィルムを得た。
これらについて、カ−ル度（Ｂ面＋１０〜Ｂ面−１５）を縦軸とし熱融着性ポリイミド層の厚み差（Ａ−Ｂ＝０〜１．５を横軸とし、１２点をプロットした。その結果、カ−ル度（Ｂ面＋１０〜Ｂ面−）と熱融着性ポリイミド層の厚み差との間には直線が引けた。
この直線から、カ−ル度：Ｂ面＋５では厚み差０．４μｍである。
つまり、線膨張係数（ＭＤ、ＴＤの平均値）が１７ｐｐｍ／℃で、カ−ル度：Ｂ面＋５の片面のみに熱融着性を有するポリイミドフィルムを得るためには、各層の厚みを１μｍ／３．６μｍ／１７．２μｍ／３．２μｍ（合計２５μｍ）とすればよいことになる。
【００４１】
実施例１において、各層の厚みが前記の厚みになるように、原料ド−プを供給した他は実施例１と同様にして、片面のみに熱融着性を有するポリイミドフィルムを巻き取りロ−ルに巻き取った。
また、この片面のみに熱融着性を有するポリイミドフィルムを使用した他は実施例２と同様にして、２組の片面銅張積層板を得た。
得られた片面のみに熱融着性を有するポリイミドフィルムは、各層の厚みが１μｍ／３．５μｍ／１７．２μｍ／３．３μｍ（合計２５μｍ）であり、カ−ル度がＢ＋８で、線膨張係数（５０−２００℃）が、ＭＤ：１８ｐｐｍ／℃、ＴＤ：１６ｐｐｍ／℃、平均：１７ｐｐｍ／℃であり、引張弾性率が７００ｋｇｆ／ｍｍ^２で、基体層ポリイミドのガラス転移温度は４００℃以下の温度で確認されず、熱融着層ポリイミドはガラス転移温度が２４２℃であり、ゲル化が実質的に生じていなく、片面銅張積層板の熱融着性を有しない耐熱性ポリイミド層間の９０°剥離強度を測定したところ１３ｇｆ／ｃｍであり良好な剥離性を示した。
以上の結果は、目的とする線膨張係数およびカ−ル度をほぼ計算通りに保有し、良好な剥離性を有する片面のみに熱融着性を有するポリイミドフィルムが得られたことを示す。
【００４２】
比較例１
耐熱性ポリイミド層塗工用ド−プをグラビアコ−タ−にて塗工しなかった他は実施例１と同様にして、熱融着性を有するポリイミドフィルムを得た。
この熱融着性を有するポリイミドフィルム２組を重ねて、最高加熱温度３８０℃で熱圧着した。
得られた積層フィルムの剥離強度は２ｋｇｆ／ｃｍ（フィルム材破）であった。
【００４３】
【発明の効果】
この発明によれば、以上のような構成を有しているため、成形加工性が良好で剥離紙を必要としない片面金属箔積層板を製造できるポリイミドフィルムおよび該ポリイミドフィルムを用いた片面金属箔積層板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３における、カ−ル度（Ｂ面＋１０〜Ｂ面−１５）を縦軸とし耐熱性ポリイミド層の両面に積層した熱融着性ポリイミド層の厚み差（Ａ−Ｂ＝０〜１．５を横軸とする、カ−ル度（Ｂ面＋表示）と熱融着性ポリイミド層の厚み差との関係を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer polyimide film having heat-fusibility on one side only, a single-sided metal foil laminate and a method for producing them, and more particularly, to a heat-resistant polyimide layer having heat-fusible polyimide layers on both sides. Further, a polyimide film having a heat-fusing property on only one side having a four-layer structure in which a heat-resistant polyimide layer having no heat-fusing property is laminated on one side, a single-sided metal foil laminate using the polyimide film, and the like The method relates to a method for producing the same.
According to the present invention, a multilayer polyimide film and a single-sided copper film having a heat-sealing property that provide an all-polyimide single-sided copper-clad plate having substantially no sticking to an apparatus in a mounting process of an electronic component and having good moldability. A laminate can be obtained.
[0002]
[Prior art]
Aromatic polyimide films are widely used for electronic devices such as cameras, personal computers, and liquid crystal displays.
In order to use an aromatic polyimide film as a substrate material for a flexible printed board (FPC) or a tape-automated bonding (TAB), a copper foil is laminated using an adhesive such as an epoxy resin. The method has been adopted.
[0003]
It has been pointed out that aromatic polyimide films are excellent in heat resistance, mechanical strength, electrical properties and the like, but impair the original properties of polyimide due to poor heat resistance of an adhesive such as an epoxy resin.
In order to solve such problems, copper is electroplated on a polyimide film without using an adhesive, or a polyamic acid solution is applied to a copper foil, dried, imidized, or thermoplastic polyimide is thermocompressed. All-polyimide substrates have also been developed.
[0004]
Further, there is known a polyimide laminate in which a film-like polyimide adhesive is sandwiched between a polyimide film and a metal foil, and a method for producing the same (Patent Document 1).
However, this polyimide laminate and its manufacturing method are not easy to handle a film-like polyimide adhesive, and the peel strength (adhesion strength) of certain polyimide films is too small to be applied.
[0005]
Further, a metal foil laminated polyimide film and a method for producing the same are known (Patent Documents 2 and 3).
However, these documents merely describe a laminate in which a multilayer polyimide film and a metal foil are firmly bonded, and the dimensional stability has not been solved.
For this reason, a flexible metal foil laminate having good dimensional stability in which metal foils are laminated on both surfaces of a thermocompression-bondable polyimide film having a three-layer structure by a double belt press has been proposed (Patent Document 4).
[0006]
[Patent Document 1]
U.S. Pat. No. 4,543,295
JP-A-8-27647.
[Patent Document 2]
JP-A-4-33847
[Patent Document 3]
JP-A-4-33848
[Patent Document 4]
JP 2000-103010 A
[0007]
[Problems to be solved by the invention]
However, according to the conventionally known technique, a single-sided metal foil laminate, for example, a single-sided copper-clad laminate requires a polyimide film having heat-fusing properties on both sides due to the need for curl suppression, and the copper foil is laminated. It is necessary to use a high heat-resistant polyimide film as a release paper on the non-exposed surface, but it is necessary to remove the release paper at the time of use, and the workability deteriorates. In addition, the single-sided copper-clad laminate excluding the release paper has a problem that the polyimide layer having a heat-fusing property is exposed, and depending on the process, it adheres to the device in the mounting process of the electronic component.
Accordingly, an object of the present invention is to use a heat-resistant heat-fusible polyimide film capable of producing a single-sided metal foil laminate, particularly a single-sided copper-clad laminate without using a release paper when laminating the metal foil, and the polyimide film. It is an object to provide a single-sided metal foil laminate, especially a single-sided copper clad laminate.
[0008]
[Means for Solving the Problems]
The present invention has a heat-fusible polyimide layer (S1 layer) having a thickness of 4 to 45 μm and a heat-fusible polyimide layer having substantially the same thickness on both sides, and the thickness of the heat-fusible polyimide layer on one surface and the heat-fusible polyimide layer on the other surface are different. The total thickness of the heat-fusible polyimide layer is 3 to 10 μm, and the heat-fusible polyimide layer (S2 layer) having a thickness of 0.1 to 2 μm and having no heat-fusibility is formed on one surface of the heat-fusible polyimide layer. The present invention relates to a polyimide film having a heat-fusing property only on one surface on which is laminated.
The present invention also relates to a single-sided metal foil laminate in which a polyimide film having heat fusibility only on one side and a copper foil are laminated by thermocompression bonding via a polyimide layer having heat fusibility.
[0009]
In addition, the present invention relates to a method in which a polyamic acid solution for providing a heat-resistant polyimide and a polyamic acid solution for providing a heat-fusible polyimide on both sides thereof have a heat-resistant polyimide layer (S1 layer) having a thickness of 4 to 45 μm, A heat-resistant polyimide layer having no heat-fusing property (S2) was laminated on one side of a self-supporting film which was laminated so that the total thickness of the fusible polyimide layer was 3 to 10 μm, and dried by heating until it exhibited self-supporting property. Layer) is applied so that the heat-resistant polyimide layer (S2 layer) has a thickness of 0.1 to 2 μm, heated, dried, and imidized. The present invention relates to a method for producing a polyimide film.
[0010]
Further, the present invention, the two sets of polyimide film and copper foil having heat-fusing property only on one side, the heat-resistant polyimide layer having no heat-fusing property inside the copper foil outside, double, The present invention relates to a method for producing a long single-sided metal foil laminate sheet in which two sets are continuously supplied to a belt press, and two sets are simultaneously subjected to thermocompression bonding and cooling under pressure, and then two sets of laminates are peeled off and separately wound.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be listed below.
1) The heat-fusible polyimide layer on one side and the heat-fusible polyimide layer on the other side have heat-fusibility only on one side, which is adjusted to a desired degree of curl by a difference in thickness. Polyimide film.
2) A polyimide film having a heat-fusible property on only one side of the above-mentioned polyimide having the same monomer composition as the heat-resistant polyimide layer (S1 layer) without the heat-fusible polyimide layer (S2 layer).
[0012]
In the present invention, a heat-fusible polyimide layer having substantially the same thickness is laminated on both sides of a heat-resistant polyimide layer as a base layer of 4 to 45 m, and the thickness of the heat-fusible polyimide layer on one side and the heat-fusible polyimide layer on the other side are laminated. The total thickness with the adhesive polyimide layer is 3 to 10 μm. The thickness of each thermocompression-bondable polyimide layer is preferably 3 to 4.
In the present invention, the polyimide film having heat-fusing property only on one side preferably has a curl degree of 0 to 10 in + B notation and a linear expansion coefficient (50 to 200 ° C.) (MD) of 13 to 13. 30 × 10 ^-6 cm / cm / ° C.
[0013]
The heat-resistant polyimide as the base layer is preferably composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter may be simply abbreviated as s-BPDA) and paraphenylenediamine (hereinafter referred to simply as s-BPDA). Hereinafter, it may be simply abbreviated as PPD) and optionally 4,4′-diaminodiphenyl ether (hereinafter may be simply abbreviated as DADE). In this case, the PPD / DADE (molar ratio) is preferably from 100/0 to 85/15.
The heat-resistant polyimide as the base layer is composed of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, paraphenylenediamine, and 4,4'-diaminodiphenyl ether. And manufactured from. In this case, it is preferable that BPDA / PMDA is 15/85 to 85/15 and PPD / DADE is 90/10 to 10/90.
[0014]
The heat-resistant polyimide as the base layer is produced from pyromellitic dianhydride, paraphenylenediamine and 4,4'-diaminodiphenyl ether. In this case, DADE / PPD is preferably 90/10 to 10/90.
Further, the heat-resistant polyimide as the base layer includes 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride and paraphenylenediamine and 4,4'-diaminodiphenyl. It is manufactured from ether. In this case, BTDA / PMDA in the acid dianhydride is preferably 20/80 to 90/10, and PPD / DADE in the diamine is preferably 30/70 to 90/10.
[0015]
Examples of the heat-resistant polyimide having no heat-fusing property in the present invention include the heat-resistant polyimide as the base layer.
In the present invention, the heat-resistant polyimide having no heat-fusing property may have a polyimide composition different from that of the heat-resistant polyimide as the base layer, but preferably has the same polyimide composition.
[0016]
As the above-mentioned heat-resistant polyimide as the base layer, it is preferable that the glass transition temperature of a single polyimide film cannot be confirmed to be 300 ° C. or higher, and particularly the linear expansion coefficient (50 to 200 ° C.) (MD) is obtained. 5 × 10 ^-6 ~ 20 × 10 ^-6 Those having a cm / cm / ° C are preferred. The tensile modulus (MD, ASTM-D882) is 300 kg / mm. ² Those described above are preferred.
In the synthesis of the base layer polyimide, the final reaction conditions are as follows: if the proportion of each component is within the above range, random polymerization, block polymerization, or two kinds of polyamic acids are synthesized in advance, and both polyamic acid solutions are mixed. To obtain a homogeneous solution.
[0017]
Using each of the above components, a substantially equimolar amount of a diamine component and a tetracarboxylic dianhydride are reacted in an organic solvent to form a polyamic acid solution (partially imidized if a uniform solution state is maintained). May be performed).
Other types and amounts of tetracarboxylic dianhydrides and diamines which do not impair the physical properties of the base layer polyimide may be used.
[0018]
The heat-fusible polyimide in the present invention can be selected from various known thermoplastic polyimides, and is preferably 1,3-bis (4-aminophenoxybenzene) (hereinafter sometimes abbreviated as TPER). ) And 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (hereinafter sometimes abbreviated as a-BPDA). ) And manufactured from. In this case, s-BPDA / a-BPDA is preferably 100/0 to 5/95.
In addition, 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane (DANPG), 4,4′-oxydiphthalic dianhydride (ODPA) and a-BPDA are used as the heat-fusible polyimide. And manufactured from.
Alternatively, it is produced from 4,4′-oxydiphthalic dianhydride (ODPA) and pyromellitic dianhydride and 1,3-bis (4-aminophenoxybenzene).
[0019]
The heat-fusible polyimide reacts each of the above-mentioned components with, as the case may be, another tetracarboxylic dianhydride and another diamine in an organic solvent at a temperature of about 100 ° C. or lower, particularly 20 to 60 ° C. Then, a solution of the polyamic acid is used, and the solution of the polyamic acid is used as a dope solution, a thin film of the dope solution is formed, the solvent is evaporated from the thin film and removed, and the polyamic acid is imide-cyclized. It can be manufactured by the following.
Further, the solution of the polyamic acid produced as described above is heated to 150 to 250 ° C., or an imidizing agent is added thereto and reacted at a temperature of 150 ° C. or less, particularly 15 to 50 ° C., to give an imide cyclization. After that, the solvent is evaporated or precipitated in a poor solvent to obtain a powder, and the powder is dissolved in an organic solution to obtain a thermocompression-bondable polyimide organic solvent solution.
[0020]
In the present invention, other tetracarboxylic dianhydrides such as 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 2,2-bis (3 , 4-dicarboxyphenyl) propane dianhydride or 2,3,6,7-naphthalenetetracarboxylic dianhydride, preferably 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride It may be replaced.
Further, other diamines such as 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, and 2,2-diamine may be used as long as the physical properties of the heat-fusible polyimide are not impaired. Bis (4-aminophenyl) propane, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenyl) diphenyl ether, 4,4′-bis (4-aminophenyl ) Diphenylmethane, 4,4'-bis (4-aminophenoxy) diphenyl ether, 4,4'-bis (4-aminophenoxy) diphenylmethane, 2,2-bis [4- (aminophenoxy) phenyl] propane, etc. Aromatic diamine having a plurality of benzene rings, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1 , 10-diaminodecane, aliphatic diamines such as 1,12-diaminododecane, and diaminodisiloxanes such as bis (3-aminopropyl) tetramethyldisiloxane. The proportion of the other aromatic diamine used is preferably 20 mol% or less, particularly preferably 10 mol% or less based on the total diamine. Further, the proportion of the aliphatic diamine and diaminodisiloxane used is preferably 20 mol% or less based on the total diamine. Exceeding this ratio lowers the heat resistance of the heat-fusible polyimide.
Dicarboxylic anhydrides, such as phthalic anhydride and its substitution, hexahydrophthalic anhydride and its substitution, succinic anhydride and its substitution, etc., in order to block the amine terminal of the heat-fusible polyimide. Phthalic anhydride may be used.
[0021]
In order to obtain the heat-fusible polyimide according to the present invention, the amount of the diamine (as the number of moles of amino group) used in the above-mentioned organic solvent is the total number of moles of the acid anhydride (tetraacid dianhydride and dicarboxylic acid anhydride). Is 0.95 to 1.0, preferably 0.98 to 1.0, and more preferably 0.99 to 1.0. When the dicarboxylic anhydride is used, the components can be reacted at a ratio of 0.05 or less as a ratio to the molar amount of the acid anhydride group of the tetracarboxylic dianhydride.
[0022]
If the use ratio of the diamine and dicarboxylic anhydride is outside the above range, the molecular weight of the resulting polyamic acid, that is, the thermocompression-bonding polyimide, is small, and the adhesive strength of the laminate with the copper foil is reduced.
For the purpose of limiting the gelling of the polyamic acid, a phosphorus-based stabilizer such as triphenyl phosphite, triphenyl phosphate or the like is used in an amount of 0.01 to 1% based on the solid content (polymer) concentration at the time of polyamic acid polymerization. Can be added.
Further, a basic organic compound can be added to the dope solution for the purpose of accelerating imidization. For example, imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, substituted pyridine, etc. are added in an amount of 0.05 to 10% by weight based on polyamic acid. %, In particular from 0.1 to 2% by weight. Since these form a polyimide film at a relatively low temperature, they can be used to avoid insufficient imidization.
Further, for the purpose of stabilizing the adhesive strength, an organic aluminum compound, an inorganic aluminum compound or an organic tin compound may be added to the polyamic acid solution for heat-fusible polyimide. For example, aluminum hydroxide, aluminum triacetylacetonate, or the like can be added to the polyamic acid at a ratio of 1 ppm or more, particularly 1 to 1000 ppm, as aluminum metal.
[0023]
The organic solvent used for the production of the polyamic acid is N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone for both heat-resistant polyimide and thermocompression-bondable polyimide. , N-diethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, N-methylcaprolactam, cresols and the like. These organic solvents may be used alone or in combination of two or more.
[0024]
In the production of a polyimide film having heat-fusibility on only one side of the present invention, for example, a three-layer co-extrusion method using a polyamic acid solution that provides a heat-resistant polyimide and a polyamic acid solution that provides a heat-fusible polyimide of the above-described base layer. By supplying the heat-resistant polyimide layer to a three-layer extrusion die so that the total thickness of the heat-fusible polyimide layers on both sides is 4 to 45 μm and the total thickness of the heat-fusible polyimide layers on both sides is 3 to 10 μm, and cast on a support. It is preferably cast on a support such as a mirror surface of a stainless steel or a belt surface to be in a semi-cured state at 100 to 200 ° C. or a dried state before that.
When the cast film is treated at a high temperature exceeding 200 ° C., there is a tendency that defects such as a decrease in adhesiveness are caused in the production of a polyimide film having heat-fusibility. The semi-cured state or a state before that means that it is in a self-supporting state by heating and / or chemical imidization.
[0025]
Next, a polyamic acid solution having a composition for providing a heat-resistant polyimide layer having no heat-fusing property on one side (side A or side B) of the heat-dried self-supporting film is coated with a heat-resistant polyimide layer having a thickness of 0.1. The coating film is uniformly coated by a coating method such as a gravure method, a screen method, or an immersion method so as to be uniformly distributed so as to have a thickness of 2 to 2 μm, and the coated film is preferably 50 to 180 ° C., particularly preferably 60 to 180 ° C. It is dried at a drying temperature of 160 ° C., more preferably 70 to 150 ° C., preferably for 0.1 to 20 minutes, particularly preferably 0.2 to 15 minutes to form a solidified film, and then preferably (1) 100 gf / mm ² Or less, particularly preferably 80 gf / mm ² A substantially free state or under low tension, and preferably (2) at a drying temperature of about 80 to 250 ° C, particularly preferably 100 to 230 ° C, preferably for about 1 to 200 minutes, particularly preferably It is preferable to form a solidified film containing the organic solvent and the produced water at a ratio of about 5 to 25% by weight, particularly 10 to 23% by weight after drying for 2 to 100 minutes.
[0026]
When raising the temperature of the solidified film in which the solvent and the produced water are preferably about 25 to 60% by weight, particularly preferably 30 to 50% by weight, to the drying temperature, the temperature is raised within a relatively short time. It is preferable that the heating rate is, for example, 10 ° C./min or more. By increasing the tension applied to the solidified film during drying, the coefficient of linear expansion of the finally obtained polyimide film can be reduced.
Then, following the above-described drying step, the drying is performed in a state where at least a pair of both edges of the solidified film is continuously or intermittently fixed by a fixing device or the like that can move together with the film continuously or intermittently. Drying and heat-treating said solidified film at a temperature above the temperature, preferably in the range 200-550 ° C, particularly preferably in the range 300-500 ° C, preferably for 1-100 minutes, especially 1-10 minutes. Preferably, the solvent and the like are sufficiently removed from the solidified film so that the content of a volatile substance composed of an organic solvent, product water, and the like in the polyimide film finally obtained is 1% by weight or less. Is sufficiently imidized to form a multi-layer polyimide film having heat-fusibility on only one side (B or A side). To form.
[0027]
As the fixing device of the solidified film, for example, a belt-shaped or chain-shaped one provided with a large number of pins or grippers at equal intervals is continuously or intermittently supplied. It is preferable to use a device in which a pair is installed along both side edges in the direction and the film can be fixed while moving continuously or intermittently with the movement of the film. Further, the solidified film fixing device can expand and contract the film being heat-treated in the width direction or the longitudinal direction at an appropriate elongation or shrinkage ratio (particularly preferably an expansion ratio of about 0.5 to 5%). It may be a device.
[0028]
In addition, the modified polyimide film produced in the above-mentioned step is again preferably subjected to 400 gf / mm. ² Or less, particularly preferably 300 gf / mm ² When heat-treated under the following low tension or no tension at a temperature of 100 to 400 ° C., preferably for 0.1 to 30 minutes, only one surface (B surface) having particularly excellent dimensional stability has heat fusion property. It can be a multilayer polyimide film. Further, the produced multilayer polyimide film having a heat-fusing property only on one side of a long sheet can be rolled up by a suitable known method.
The multilayer polyimide film of the present invention having a heat-sealing property on only one side has a coefficient of linear expansion (50 to 200 ° C.) (MD) of 13 to 30 ppm / ° C. and adjusts the curl according to the user's needs. It can be adjusted from 10 to -10 (A side +10) in B side + display, and preferably from 0 to 10 in B side + display.
[0029]
The method of adjusting the degree of curl by using a multi-layer polyimide film having heat-fusibility only on one side of the present invention will be described below. When the coefficient of linear expansion is about 18 ppm / ° C., the thickness of the heat-resistant polyimide layer is, for example, 15 μm, the thickness of the heat-resistant polyimide layer having no heat-fusing property is, for example, 1 μm, and the thickness of the heat-fusing polyimide layer is For example, the heat-fusible polyimide is changed by changing the degree of curl (B side +10 to B side -15) on the vertical axis by changing the A side to 3.0 to 4.0 μm and the B side to 2.5 to 3.5 μm. The thickness difference (AB = 0 to 1.5 is plotted on the horizontal axis), and each point is plotted. As a result, the degree of curl (B side + 10 to B side−) and the thickness of the heat-fusible polyimide layer are plotted. A straight line can be drawn between the difference and the straight line, from which the thickness difference of the heat-fusible polyimide layer corresponding to a certain degree of curl can be obtained.
In the case of laminating with a metal foil, if the degree of curl is preferably, for example, B side +3 to +5, the desired degree of curl can be adjusted by adopting the corresponding thickness difference of the heat-fusible polyimide layer. is there.
[0030]
Examples of the metal foil (for a circuit) used in the present invention include various metal foils such as copper, aluminum, gold, and alloy foils, and preferably, copper foils such as a rolled copper foil and an electrolytic copper foil. .
The metal foil preferably has a surface roughness Rz of 0.5 μm or more. The metal foil preferably has a surface roughness Rz of 7 μm or less, particularly 5 μm or less. Such a metal foil, for example, a copper foil, is known as VLP, LP (or HTE).
The thickness of the metal foil is not particularly limited, but is preferably 2 to 35 μm, particularly preferably 5 to 18 μm.
When the thickness of the metal foil is 5 μm or less, a metal foil with a carrier, for example, a copper foil with an aluminum foil carrier is used.
[0031]
In the present invention, for example, a polyimide film and a metal foil having a heat-sealing property only on one side (B side) are continuously formed with at least one pair of pressing members, and the temperature of the pressing portion is set to a value of the thermocompression bonding polyimide. By thermocompression bonding under heating at a temperature of 30 ° C. or higher and 420 ° C. or lower than the glass transition temperature, a long single-sided metal foil laminate can be obtained.
Examples of the pressure member include a pair of pressure-bonded metal rolls (the pressure-bonded portion may be made of metal or ceramic sprayed metal) or a double belt press, particularly those capable of thermocompression and cooling under pressure. Among them, a hydraulic double belt press is particularly preferable.
In the present invention, the above-mentioned pressure member, for example, a metal roll, preferably a double belt press is used, and the above-mentioned multilayer polyimide film, metal foil and reinforcing material are superimposed and continuously heated. By crimping, a polyimide single-layered body can be manufactured.
[0032]
In particular, when a polyimide film and a metal foil having a heat-fusing property only on one side are supplied to a pressing member in a roll-wound state, respectively, the polyimide single-layered body can be obtained in a roll-wound state. It is suitable.
In the method of the present invention, in particular, each of the two sets of the polyimide film and the metal foil having the heat-sealing property only on one side is placed with the heat-resistant polyimide layer side having no heat-fusing property (Side A) inside, and the metal foil is put on the metal foil. Outside, and continuously supplied to the double belt press, two sets of thermocompression bonding at the same time, the temperature of the pressurized part is 30 ° C or more and 420 ° C or less from the glass transition temperature of the heat-fusible polyimide under heating. After cooling, it is preferable from the viewpoint of productivity that a long single-sided metal foil laminate is obtained by peeling the two sets of laminates and winding them separately.
[0033]
The single-sided metal foil laminate of the present invention comprises a multilayer polyimide film having heat fusibility and a metal foil which are firmly laminated, preferably with a 90 ° peel strength of 1.0 kgf / cm or more, and are made of ceramic, heat-resistant Polyimide film, other substrates such as metal and not only at room temperature but also at the time of heating at about 300 ℃ without adhesion, for example, even when laminated under pressure at a temperature of about 300 ℃ with other heat-resistant polyimide film The 90 ° peel strength is 20 gf / cm or less.
The single-sided metal foil laminate of the present invention preferably has a multilayer polyimide film having a linear expansion coefficient (50 to 200 ° C.) (MD) of 13 to 30 × 10 3. ^-6 cm / cm / ° C.
The single-sided metal foil laminate of the present invention has good formability, and can be used for punching, bending, drawing, forming metal wiring, and thermocompression bonding of electronic circuits on wiring.
[0034]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
In each of the following examples, parts means parts by mass.
In each of the following examples, the physical property evaluation and the peel strength of the copper foil laminated film were measured according to the following methods.
Linear expansion coefficient: Measured (MD) at a heating rate of 20 to 200 ° C. and 5 ° C./min.
Peel strength of laminate: 90 ° peel strength was measured according to IPC-FC-2413B.
[0035]
Reference Example 1
Synthetic example 1 of dope for polyimide production of base layer
N-methyl-2-pyrrolidone (NMP) was added to a reaction vessel equipped with a stirrer and a nitrogen inlet tube, and paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride were further added. (S-BPDA) at a molar ratio of 1000: 998 so that the monomer concentration became 18% (% by weight, the same applies hereinafter). After completion of the addition, the reaction was continued for 3 hours while maintaining the temperature at 50 ° C. The obtained polyamic acid solution was a brown viscous liquid, and the solution viscosity at 25 ° C. was about 1500 poise. This solution was used as a substrate dope.
[0036]
Synthetic example 1 of dope for heat-fusible polyimide production
NMP was added to a reaction vessel equipped with a stirrer and a nitrogen inlet tube, and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, s-BPDA, 1,3-bis (4-aminophenoxy) was further added. ) Benzene and DADE were added at a molar ratio of 20: 80: 50: 50 to give a monomer concentration of 22%, and triphenyl phosphate was added at 0.1% by weight of the monomer. After completion of the addition, the reaction was continued for 1 hour while maintaining the temperature at 25 ° C. This polyamic acid solution had a solution viscosity at 25 ° C. of about 2000 poise. This solution was used as a dope.
[0037]
Synthesis example 1 of heat-resistant polyimide layer coating solution
PPD and s-BPDA were added to N-methyl-2-pyrrolidone at a molar ratio of 100: 96 so that the monomer concentration became 18% (% by weight, the same applies hereinafter) to obtain a polyamic acid solution. / 3,3 ', 4,4'-biphenyltetracarboxylic acid (s-BPTA) was added to make the diamine equimolar to prepare a stock solution, diluted with NMP, and a polyamic acid having a monomer concentration of 5%. An acid solution was obtained. This solution was used as a coating dope.
[0038]
Example 1
Using a film forming apparatus provided with a three-layer extrusion molding die (multi-manifold type die), a three-layer extrusion die is used for forming the base layer polyimide production dope and the heat-fusible polyimide production dope. And then continuously dried with hot air at 130 ° C. and peeled off to form a self-supporting film. One side (A side) of the self-supporting film was coated with a heat-resistant polyimide layer. The working dope is coated with a gravure coater, and the temperature is gradually raised from 150 ° C. to 450 ° C. in a heating furnace to remove the solvent and imidize, and the long side has a thickness of 1 μm on one surface. A heat-fusible polyimide film having no heat-fusible property was laminated on only one side of the laminate, and a heat-fusible polyimide film was wound on a take-up roll.
The obtained polyimide film having heat-sealing property only on one side has a thickness of each layer of 1 μm / 3.5 μm / 17.2 μm / 3.3 μm (total 25 μm), a curl degree of B + 8, and linear expansion. Coefficients (50-200 ° C.) are MD: 18 ppm / ° C., TD: 16 ppm / ° C., average: 17 ppm / ° C., and the tensile modulus is 700 kgf / mm. ² The glass transition temperature of the polyimide of the base layer was not confirmed at a temperature of 400 ° C. or lower, and the polyimide of the heat-sealing layer had a glass transition temperature of 242 ° C., and substantially no gelation occurred.
[0039]
Example 2
Electrolytic copper foil (Fukuda Metal Foil Kogyo Co., Ltd.) rolled from both sides by continuously supplying a polyimide film having heat-fusing property only on one side to about 150 ° C and supplying it to a double belt press. , CF-T9, VP, Rz: 5 μm, thickness: 18 μm) The temperature of the heating zone (max. Heating temperature) 380 ° C, cooling zone temperature (minimum cooling temperature) 117 ° C, thermocompression bonding and cooling under continuous pressurization, peeling off two sets of single-sided copper-clad laminates to form It was wound up on a take-up roll.
The peel strength on the copper foil side of the obtained one-layer sheet was 1.1 kgf / cm.
Separately, the 90 ° peel strength between the heat-resistant polyimide layers having no heat-sealing property of the two sets of single-sided copper-clad laminates was 13 gf / cm.
[0040]
Example 3
From the heat-resistant polyimide film and the heat-fusible polyimide film manufactured separately from Example 1, the thickness of both layers was converted by using the linear expansion coefficient of the heat-resistant polyimide film: 12 ppm / ° C. , Average value of TD) of 17 ppm / ° C.
In Example 1, the thickness of the heat-resistant polyimide layer was 17.4 μm, the thickness of the heat-resistant polyimide layer having no heat-fusing property was 1 μm, and the thickness of the heat-fusing polyimide layer was, for example, 3. By varying the thickness from 0 to 4.0 µm and from 2.5 to 3.5 µm on the B side, a polyimide film having heat-fusibility only on one side having a thickness difference between various heat-fusible polyimide layers was obtained.
With respect to these, 12 points were plotted with the degree of curl (B side +10 to B side -15) as the vertical axis and the thickness difference of the heat-fusible polyimide layer (AB = 0 to 1.5 as the horizontal axis). As a result, a straight line was drawn between the degree of curl (plane B + 10 to plane B-) and the difference in thickness of the heat-fusible polyimide layer.
From this straight line, the thickness difference is 0.4 μm at the degree of curl: surface B + 5.
In other words, in order to obtain a polyimide film having a coefficient of linear expansion (average value of MD and TD) of 17 ppm / ° C. and a degree of curl of only one side of B side + 5, the thickness of each layer must be 1 μm. /3.6 μm / 17.2 μm / 3.2 μm (total 25 μm).
[0041]
In the same manner as in Example 1, except that the raw material dope was supplied so that the thickness of each layer became the above-mentioned thickness, a polyimide film having heat-fusing property was wound on only one side and rolled. Rolled up.
Further, two sets of single-sided copper-clad laminates were obtained in the same manner as in Example 2 except that a polyimide film having heat-sealing property was used only on one side.
The obtained polyimide film having heat-sealing property only on one side has a thickness of each layer of 1 μm / 3.5 μm / 17.2 μm / 3.3 μm (total 25 μm), a curl degree of B + 8, and linear expansion. Coefficients (50-200 ° C.) are MD: 18 ppm / ° C., TD: 16 ppm / ° C., average: 17 ppm / ° C., and the tensile modulus is 700 kgf / mm. ² The glass transition temperature of the polyimide of the base layer was not confirmed at a temperature of 400 ° C. or less, and the polyimide of the heat-sealing layer had a glass transition temperature of 242 ° C., substantially no gelation occurred, and was a single-sided copper-clad laminate. When the 90 ° peel strength between heat-resistant polyimide layers having no heat-fusible property was measured, the peel strength was 13 gf / cm, indicating good peelability.
The above results show that a polyimide film having the desired linear expansion coefficient and the degree of curl almost as calculated and having heat-bonding properties on only one side having good peelability was obtained.
[0042]
Comparative Example 1
A heat-fusible polyimide film was obtained in the same manner as in Example 1 except that the heat-resistant polyimide layer coating dope was not coated with a gravure coater.
Two sets of this polyimide film having heat-sealing property were laminated and thermocompression bonded at a maximum heating temperature of 380 ° C.
The peel strength of the obtained laminated film was 2 kgf / cm (film material breakage).
[0043]
【The invention's effect】
According to the present invention, a polyimide film capable of producing a single-sided metal foil laminate having good formability and requiring no release paper because of the above-described structure, and a single-sided metal foil using the polyimide film A laminate can be obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing the difference in thickness between heat-fusible polyimide layers laminated on both surfaces of a heat-resistant polyimide layer with the degree of curl (B side +10 to B side -15) as a vertical axis in Example 3. It is a figure which shows AB = 0-1.5, and shows the relationship between the curl degree (B side + display) and the thickness difference of a heat-fusible polyimide layer.

Claims

A heat-fusible polyimide layer (S1 layer) having a thickness of 4 to 45 μm has a heat-fusible polyimide layer having substantially the same thickness on both sides, and the thickness of the heat-fusible polyimide layer on one side and the heat-fusible polyimide on the other side The total thickness of the heat-fusible polyimide layer is 3 to 10 μm, and a heat-resistant polyimide layer (S2 layer) having a thickness of 0.1 to 2 μm and having no heat-fusibility is laminated on one surface of the heat-fusible polyimide layer. A polyimide film having heat-sealing properties on only one side.

The heat-fusible polyimide layer on one side only according to claim 1, wherein the heat-fusible polyimide layer on one side and the heat-fusible polyimide layer on the other side are adjusted to a desired degree of curl by a difference in thickness. A polyimide film having:

2. The polyimide having heat-fusing property on only one side according to claim 1, wherein the heat-resistant polyimide layer (S2 layer) having no heat-fusing property is made of polyimide having the same monomer composition as the heat-resistant polyimide layer (S1 layer). the film.

A single-sided metal foil laminate in which the polyimide film having heat-fusibility only on one side according to any one of claims 1 to 3 and a metal foil are laminated by thermocompression bonding via a polyimide layer having heat-fusibility. Board.

A polyamic acid solution that provides a heat-resistant polyimide and a polyamic acid solution that provides a heat-fusible polyimide on both sides thereof are mixed with a heat-resistant polyimide layer (S1 layer) having a thickness of 4 to 45 μm and a heat-fusible polyimide layer on both sides. Laminated so that the total thickness is 3 to 10 μm, and heat-dried until the self-supporting film exhibits self-supporting property. A method for producing a polyimide film having a heat-fusible property on only one side, which is coated with a polyamic acid solution so that the heat-resistant polyimide layer (S2 layer) has a thickness of 0.1 to 2 μm, dried by heating, and imidized.

The two sets of the polyimide film and the metal foil each having only one surface according to any one of claims 1 to 3, and the metal foil outside the heat-resistant polyimide layer having no heat fusion. And then continuously supply them to a double belt press, heat-press and cool two sets simultaneously under pressure, then peel off the two sets of laminates and wind them separately to produce a long single-sided metal foil laminate Law.