JP4231227B2

JP4231227B2 - Method for producing heat-resistant flexible laminate

Info

Publication number: JP4231227B2
Application number: JP2002002594A
Authority: JP
Inventors: 辻宏之; 松久保慎治; 長谷直樹; 伏木八洲男
Original assignee: Kaneka Corp
Current assignee: Kaneka Corp
Priority date: 2002-01-09
Filing date: 2002-01-09
Publication date: 2009-02-25
Anticipated expiration: 2022-01-09
Also published as: JP2003200496A

Description

【０００１】
【発明の属する技術分野】
本発明は、加圧加熱成形装置で製造される積層板の製造方法に関する。特には、電子電気機器等に用いられるフレキシブル積層板の製造方法に関するものである。
【０００２】
【従来の技術】
電子電気機器用印刷回路基板に用いられる積層板には、金属箔が熱硬化性樹脂等の熱硬化型接着剤によって貼付された積層板（以下、熱硬化型の積層板と表す）と、熱可塑性樹脂等の熱融着型接着剤によって貼付された積層板（以下、熱融着型の積層板と表す）がある。
【０００３】
熱硬化型の積層板の製造方法は、従来より種々研究されており、樹脂含浸紙、樹脂含浸ガラス布等と金属箔を多段プレスや真空プレスを用いてプレスし、その後、高温で数時間熱硬化させてリジッド積層板を得る方法や、ロール状の材料を１対の加熱ロールに挟んでラミネートし、その後、高温で数時間熱硬化させてフレキシブル積層板を得る方法、加熱ロールの代わりにダブルベルトプレス装置を用いて熱ラミネートする方法等が実施されている。その際、以下に示す問題を解決する目的で、装置の加圧面と被積層材料との間に保護材料を挟んで加圧加熱成形する場合がある。すなわち、金属箔表面の傷や打痕の発生（特開昭６０−１０９８３５）や熱ラミネート後の硬化炉における積層板の反りの発生（特開平４−８９２５４）、あるいは樹脂溜まりのある平滑性に乏しい樹脂含浸紙や樹脂含浸ガラス布等により滑らかなラミネート加工が阻害される等の問題が発生する場合に保護材料を用いるときがある。また、熱融着型では、特開平１１−２９８１１４に、接着フィルムの片面に銅箔をシリコンゴムロールでラミネートする時、銅箔を貼らない面に保護フィルム（非熱可塑性のポリイミドフィルム）を配してラミネートを行う事例が記載されている。しかしながら、該公報の場合、この保護フィルムは、接着フィルムがラミネートロールに貼りつかないことを目的に使用している。
【０００４】
【発明が解決しようとする課題】
上記した熱硬化型の積層板を製造する場合、加圧加熱成形温度は２００℃以下である場合が殆どである。この程度の加熱温度では、被積層材料にかかる熱応力が小さく、熱ラミネート時のシワ等の外観不良は発生しにくい。
【０００５】
ところが、熱融着型の積層板を製造する場合、接着層を構成する熱可塑性樹脂のガラス転移温度（Ｔｇ）以上の温度で加圧加熱を行わなければ熱融着ができない。一方、電子電気機器用積層板は、部品実装の過程で高温加熱を受けるので、接着層を構成する熱可塑性樹脂には少なくとも１８０℃以上のＴｇが求められる。更にその熱融着のためには２００℃以上の熱ラミネート温度が必要となる。この様な高温でのラミネートでは、被積層材料の熱膨張・熱収縮の変化が大きくなり、ラミネートされた積層体にシワ等の外観不良を生じやすいという問題がある。
【０００６】
シワの発生原因をより詳しく説明すると、熱ロールラミネート機で銅箔と熱可塑性ポリイミドをラミネートする場合、熱ロールラミネート機の加熱加圧状態のプレスロール間を通過することで、銅箔と熱可塑性ポリイミドが貼り合わされる。ラミネート時、各被積層材料は熱によって膨張した状態にあるが、一般に銅箔の線膨張係数よりも熱可塑性ポリイミドの線膨張係数は大きいため、銅箔より面方向に大きく伸びた状態で熱可塑性ポリイミドは銅箔と熱ラミネートされ、逆に、冷却時には熱可塑性ポリイミドは銅箔より面方向に大きく縮む。このため、できた積層板は面方向にシワを生じる。これは、圧力が開放されるラミネート直後も、材料が熱を保持しており、その温度が熱可塑性ポリイミドのＴｇよりも高いために熱可塑性ポリイミドは流動状態にあり、シワの発生を抑止できないことも一因となっている。
【０００７】
このシワを抑制することを目的に、ラミネート時に加圧面と被積層材料との間にポリイミドフィルムのようなラミネート時の高温にも耐えうる保護材料を配してラミネートし、ラミネート後も保護材料をラミネートされた積層板からすぐに剥がさず、積層板の温度が接着フィルムのＴｇ以下になってから剥離する方法がある。ラミネート後の熱可塑性ポリイミドは収縮しようとするが、この方法による保護材料を用いることによって、ラミネートされた積層板の面方向の動きを抑制し、さらには熱可塑性ポリイミドの動きが制限されてシワが発生しないことを利用している。しかしながら、この方法では、保護材料と銅箔との密着性が重要であり、例えば、保護材料側の銅箔の表面粗さが粗いとラミネート直後すぐに保護材料と銅箔が剥離してしまい、積層板にシワを生じてしまう問題があった。
【０００８】
【課題を解決するための手段】
本発明は前記問題点に鑑み、熱ラミネート時に生じるシワ等の外観不良のないフレキシブル基板材料として好適な積層板を提供するものである。
【０００９】
すなわち、本発明者らは、上記同様の系で銅箔の表面粗さが違うといった銅箔の種類に関係なく、表面性の良好な積層板を製造することができることを見出したのである。
【００１０】
すなわち本発明は、接着フィルムの両側に金属材料を配し、熱ロールラミネート装置により連続的に貼り合わせてなる積層板の製造方法であって、該装置の加圧面と前記金属材料との間に、片面に熱可塑性樹脂を積層した保護材料を、該熱可塑性樹脂が前記金属材料と接するように配置し、２００℃以上の加圧加熱成形を行った後、接着フィルム接着層のガラス転移温度（Ｔｇ）以下で且つ保護材料と被積層材料の密着強度が０．１〜５Ｎ／ｃｍの範囲で、該保護材料を積層板から剥離することを特徴とする積層板の製造方法である。ここでいう、保護材料とは積層板の非構成材料をさす。密着強度が０．１Ｎ／ｃｍより小さいと非積層材料の収縮に耐え切れず剥離しシワを生じてしまう。また、５Ｎ／ｃｍより高いと剥離時に被積層材料に応力がかかりカール等の外観上の問題が発生する。さらに、本発明は、前記接着フィルムとして、接着成分中に熱可塑性ポリイミドを５０重量％以上含有する接着フィルムを用いることを特徴とする積層板の製造方法である。さらに、本発明は、前記金属材料として、厚みが５０μｍ以下の銅箔を用いることを特徴とする積層板の製造方法である。さらに、本発明は、前記保護材料として、ポリイミドフィルムを用いることを特徴とする積層板の製造方法である。
【００１１】
【発明の実施の形態】
以下、本発明の詳細について説明する。
【００１２】
本発明の製造方法で得られる積層板の用途は特に限定されるものではないが、主として電子電気用のフレキシブル積層板として用いられるものである。
【００１３】
接着フィルムとしては、熱融着性を有する樹脂から成る単層フィルム、熱融着性を有さないコア層の両側に熱融着性を有する樹脂層を形成して成る複数層フィルム、紙、ガラスクロス等の基材に熱融着性を有する樹脂を含浸したフィルム等が挙げられるが、ガラスクロス等の剛性のある基材を使用すると屈曲性が劣ることより、フレキシブル積層板用の接着フィルムとしては、熱融着性を有する樹脂から成る単層フィルム、熱融着性を有さないコア層の両側に熱融着性を有する樹脂層を形成して成る複数層フィルムが好ましい。熱融着性を有する樹脂から成る単層フィルム、熱融着性を有さないコア層の両側に熱融着性を有する樹脂層を形成して成る複数層フィルムとしては耐熱性を有するものが好ましく、接着成分が熱可塑性ポリイミド系成分から成るもの、例えば、熱可塑性ポリアミドイミド、熱可塑性ポリエーテルイミド、熱可塑性ポリエステルイミド等が好適に用いられ得る。これらの耐熱性の熱可塑性樹脂を接着成分中の５０％以上含有する接着フィルムも本発明には好ましく用いられ、エポキシ樹脂やアクリル樹脂のような熱硬化性樹脂等を配合した接着フィルムの使用も好ましい。各種特性の向上のために接着フィルムには種々の添加剤が配合されていても構わない。
【００１４】
接着フィルムの構成は、耐熱性の接着層を外側に有するものであれば、熱融着性の接着成分のみから成る単層でも構わないが、寸法特性等の観点から、熱融着性を有さないコア層の両側に熱融着性の接着層を有する３層構造のフィルムが好ましい。この熱融着性を有さないコア層は、耐熱性があれば特に限定しないが、非熱可塑性のポリイミドフィルムの使用が好ましい。
【００１５】
接着フィルムの作製方法については特に限定しないが、接着剤層単層からなる場合、ベルトキャスト法、押出法等により製膜することができる。また、接着フィルムの構成が接着層／熱融着性を有さないコア層／接着層という３層からなる場合、熱融着性を有さないコア層（例えば、耐熱性フィルム）の両面に接着剤を、片面ずつ、もしくは両面同時に塗布して３層の接着フィルムを作製する方法や、耐熱性フィルムの両面に接着成分のみからなる単層の接着フィルムを配して貼り合わせて３層の接着フィルムを作製する方法がある。接着剤を塗布して３層の接着フィルムを作製する方法において、特にポリイミド系の接着剤を使用する場合、ポリアミック酸の状態で耐熱性フィルムに塗布し、次いで乾燥させながらイミド化を行う方法と、そのまま可溶性ポリイミド樹脂を塗布し、乾燥させる方法があり、接着剤層を形成する方法は特に問わない。その他に、接着層／耐熱融着性を有さないコア層／接着層のそれぞれの樹脂を共押出して、一度に耐熱性接着フィルムを製膜する方法もある。
【００１６】
金属材料としては、特に限定しないが、電子電気機器用に用いられる積層板の場合、導電性・コストの点から銅箔を用いるのが好ましい。また、金属箔の厚みについては、銅箔の厚みが薄いほど回路パターンの線幅を細線化できることから、５０μｍ以下の銅箔が好ましい。特に３５μｍ以下の銅箔はそれ以上の厚みの銅箔に比べてコシがなく、熱ラミネートする際にシワを生じやすいため、３５μｍ以下の銅箔について、本発明は顕著な効果を発揮する。また、銅箔の種類としては圧延銅箔、電解銅箔、ＨＴＥ銅箔等が挙げられ特に制限はなく、これらの表面に接着剤が塗布されていても構わない。
【００１７】
熱ロールラミネート装置については、被積層材料を加熱して圧力を加えてラミネートする装置であれば特にこだわらない。加熱方法について、所定の温度で加熱することができるものであれば特にこだわらず、熱媒循環方式、熱風加熱方式、誘電加熱方式等が挙げられる。加熱温度は２００℃以上が好ましいが、電子部品実装のために積層板が雰囲気温度２４０℃の半田リフロー炉を通過する用途に供される場合には、それに応じたＴｇを有する熱融着フィルムを使用するため２４０℃以上の加熱が好ましい。プレスロールの材質はゴム、金属等、特に限定しないが、ラミネート温度が２８０℃以上の高温になると、ゴムロールは劣化するため使用できず、金属ロールが好ましい。加圧方式についても所定の圧力を加えることができるものであれば特にこだわらず、油圧方式、空気圧方式、ギャップ間圧力方式等が挙げられ、圧力は特に限定されない。
【００１８】
保護材料は、ラミネートした製品のシワ発生等の外観不良から保護する目的を満たすものであれば何でも良い。ただし、加工時の温度に耐え得るものでなければならず、例えば２５０℃で加工する場合は、それ以上の耐熱性を有するポリイミドフィルム等が有効である。保護材料の厚みは特に限定しないが、ラミネート後の積層板のシワ形成を抑制する目的から、５０μｍ以上の厚みが好ましい。保護材料の厚みが７５μｍ以上であればシワ形成をほぼ完全に抑制できるため好ましい。さらに好ましくは１２５μｍ以上である。
【００１９】
保護材料はポリイミド等のフィルム単体でも接着フィルム接着層のＴｇ以下で０．１〜５Ｎ／ｃｍの範囲で剥離可能なものであれば問題なく、保護材料の片面にラミネート時に粘着性を示す樹脂を配したものも使用できる。たとえば、ラミネート温度付近にＴｇを有する熱可塑性の樹脂が考えられる。通常、耐熱性フレキシブル積層板を製造するときのラミネート温度は２００℃以上と高温であり、その温度に耐えうる材料として熱可塑性ポリイミド樹脂、熱可塑性ポリアミド樹脂、熱可塑性ポリアミドイミド樹脂等の耐熱性の熱可塑性樹脂が有効である。
【００２０】
保護材料の片面に熱可塑性樹脂層を形成する方法は、所定の樹脂構成のものが得られれば特にこだわらなく、保護材料の片面に熱可塑性樹脂を塗布・乾燥をおこなう方法やあらかじめ熱可塑性樹脂フィルムを形成しておき、その後で保護材料と貼り合わせて作製する方法、保護材料を作製する時、同時に片面に熱可塑性樹脂層も形成する方法等が使用できる。
【００２１】
保護材料の片面に形成する熱可塑性樹脂の厚みは特にこだわらないが、熱可塑性樹脂層が厚すぎると、金属材料と剥離する際、熱可塑性樹脂層の凝集破壊が起こり、金属材料に転写する可能性があるため、１０μｍ以下の厚みが好ましい。さらに好ましくは５μｍ以下である。
【００２２】
保護材料を剥離する際の積層板の温度は、熱可塑性樹脂を被積層材料として使用する場合には、そのＴｇ以下の温度が好ましい。より好ましくはＴｇよりも５０℃以上低い温度、更に好ましくはＴｇよりも１００℃以上低い温度である。最も好ましくは室温まで冷却された時点で保護材料を積層板から剥離するのが好ましい。
【００２３】
以下実施例を記載して本発明をより詳細に説明する。
【００２４】
【実施例】
実施例中のガラス転移温度（Ｔｇ）は、島津製作所ＤＳＣＣＥＬＬＳＣＣ−４１（示差走査熱量計）により、窒素気流下、昇温速度１０℃／分にて、室温から４００℃までの温度範囲で測定した。
【００２５】
（参考例１）非熱可塑性ポリイミドフィルム両面にＴｇ１９０℃の熱可塑性ポリイミド樹脂成分を有する２５μｍ厚の三層構造の接着フィルム（鐘淵化学工業株式会社製ＰＩＸＥＯ−ＢＰ）の両側に表面性の良好な１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝０．７９μｍ）を配し、さらにその両側に保護フィルムとして１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機により、温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cmの条件でラミネートした後、室温まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は０．５Ｎ／ｃｍであった。その結果、外観にシワ等の不良のないフレキシブル積層板を得た。
【００２６】
（実施例１）参考例１で用いた３層構造の接着フィルムの両側に表面性の良好な１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝０．７９μｍ）を配し、さらにその両側に保護フィルムとして片面に２μｍの熱可塑性樹脂（Ｔｇ３４０℃）を塗布した１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、１５０℃まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は１．５Ｎ／ｃｍであった。その結果、外観にシワ等の不良のないフレキシブル積層板を得た。
【００２７】
（実施例２）参考例１で用いた３層構造の接着フィルムの両側に表面性の良好な１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝０．７９μｍ）を配し、さらにその両側に保護フィルムとして片面に２μｍの熱可塑性樹脂（Ｔｇ３４０℃）を塗布した１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、室温まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は２Ｎ／ｃｍであった。その結果、外観にシワ等の不良のないフレキシブル積層板を得た。
【００２８】
（実施例３）参考例１で用いた３層構造の接着フィルムの両側に表面性の良くない１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝１．８４μｍ）を配し、さらにその両側に保護フィルムとして片面に２μｍの熱可塑性樹脂（Ｔｇ３４０℃）を塗布した１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、１５０℃まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は１Ｎ／ｃｍであった。その結果、外観にシワ等の不良のないフレキシブル積層板を得た。
【００２９】
（実施例４）参考例１で用いた３層構造の接着フィルムの両側に表面性の良くない１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝１．８４μｍ）を配し、さらにその両側に保護フィルムとして片面に２μｍの熱可塑性樹脂（Ｔｇ３４０℃）を塗布した１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、常温まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は１．５Ｎ／ｃｍであった。その結果、外観にシワ等の不良のないフレキシブル積層板を得た。
【００３０】
（比較例１）参考例１で用いた３層構造の接着フィルムの両側に表面性の良好な１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝０．７９μｍ）を配し、さらにその両側に保護フィルムとして片面に２μｍの熱可塑性樹脂（Ｔｇ２００℃）を塗布した１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、室温まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。この時の保護フィルムとフレキシブル積層板との密着強度は７Ｎ／ｃｍであった。その結果、カールの大きいフレキシブル積層板しか得られなかった。
【００３１】
（比較例２）参考例１で用いた３層構造の接着フィルムの両側に表面性の良くない１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝１．８４μｍ）を配し、さらにその両側に保護フィルムとして１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、室温まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。しかしながら、保護フィルムとフレキシブル積層板とが剥離してしまい、シワを生じた。その結果、外観にシワのあるフレキシブル積層板しか得られなかった。
【００３２】
（比較例３）参考例１で用いた３層構造の接着フィルムの両側に表面性の良くない１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝１．８４μｍ）を配し、さらにその両側に保護フィルムとして１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、１５０℃まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。しかしながら、保護フィルムとフレキシブル積層板とが剥離してしまい、シワを生じた。その結果、外観にシワのあるフレキシブル積層板しか得られなかった。
【００３３】
（比較例４）参考例１で用いた３層構造の接着フィルムの両側に表面性の良好な１８μｍの電解銅箔（光沢面の表面の中心線平均粗さＲｚ＝０．７９μｍ）を配し、さらにその両側に保護フィルムとして１２５μｍのポリイミドフィルム（鐘淵化学工業株式会社製アピカル１２５ＮＰＩ）を配して、熱ロールラミネート機（温度３６０℃、Ｌ／Ｓ２．０m/min、線圧５００N/cm）でラミネートさせた後、２５０℃まで冷却させ、フレキシブル積層板から保護フィルムを剥離してフレキシブル積層板を作製した。その結果、外観にシワのあるフレキシブル積層板しか得られなかった。
【００３４】
【発明の効果】
接着フィルムの両側に金属材料を配し、熱ロールラミネート装置により連続的に貼り合わせてなる積層板の製造方法であって、該装置の加圧面と前記金属材料との間に、片面に熱可塑性樹脂を積層した保護材料を、該熱可塑性樹脂が前記金属材料と接するように配置し、２００℃以上の加圧加熱成形を行った後、接着フィルム接着層のガラス転移温度（Ｔｇ）以下で且つ保護材料と被積層材料の密着強度が０．１〜５Ｎ／ｃｍの範囲で、該保護材料を積層板から剥離することによって、銅箔の表面粗さに関わらず、外観良好な積層板を得ることが出来る。従って本発明は、特に電子電気機器用のフレキシブル積層板として好適な材料を提供するものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a laminated plate manufactured by a pressure heating molding apparatus. In particular, the present invention relates to a method for manufacturing a flexible laminate used for electronic and electrical equipment.
[0002]
[Prior art]
A laminate used for a printed circuit board for electronic and electrical equipment is a laminate in which a metal foil is pasted with a thermosetting adhesive such as a thermosetting resin (hereinafter referred to as a thermosetting laminate), heat There is a laminate (hereinafter, referred to as a heat-sealable laminate) pasted with a heat-sealable adhesive such as a plastic resin.
[0003]
Various methods for producing thermosetting laminates have been studied in the past, and resin impregnated paper, resin impregnated glass cloth, etc. and metal foil are pressed using a multistage press or vacuum press, and then heated at high temperature for several hours. A method of obtaining a rigid laminate by curing, a method of laminating a roll-shaped material between a pair of heating rolls, and then thermosetting at a high temperature for several hours to obtain a flexible laminate, double instead of a heating roll A method of heat laminating using a belt press apparatus has been implemented. At that time, for the purpose of solving the problems described below, there is a case where pressure heating molding is performed with a protective material sandwiched between the pressing surface of the apparatus and the material to be laminated. That is, generation of scratches and dents on the surface of the metal foil (Japanese Patent Laid-Open No. Sho 60-109835), warpage of the laminated plate in a curing furnace after heat lamination (Japanese Patent Laid-Open No. Hei 4-89254), or smoothness with a resin pool In some cases, a protective material is used when problems such as hindering smooth lamination due to poor resin-impregnated paper or resin-impregnated glass cloth occur. In addition, in the heat fusion type, when a copper foil is laminated on one surface of an adhesive film with a silicon rubber roll, a protective film (non-thermoplastic polyimide film) is disposed on the surface on which the copper foil is not attached in JP-A-11-298114. Examples of laminating are described. However, in the case of this publication, this protective film is used for the purpose of preventing the adhesive film from sticking to the laminate roll.
[0004]
[Problems to be solved by the invention]
In the case of producing the above-mentioned thermosetting laminate, the pressure heating molding temperature is almost 200 ° C. or less. At such a heating temperature, the thermal stress applied to the material to be laminated is small, and appearance defects such as wrinkles during thermal lamination are unlikely to occur.
[0005]
However, in the case of producing a heat-bonding type laminate, heat-bonding cannot be performed unless pressure heating is performed at a temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin constituting the adhesive layer. On the other hand, since the laminate for electronic and electrical equipment is subjected to high temperature heating in the process of component mounting, the thermoplastic resin constituting the adhesive layer is required to have a Tg of at least 180 ° C. or higher. Furthermore, a heat laminating temperature of 200 ° C. or higher is required for the heat fusion. In such a high temperature laminate, there is a problem that a change in thermal expansion / shrinkage of the material to be laminated becomes large, and appearance defects such as wrinkles are likely to occur in the laminated laminate.
[0006]
The cause of wrinkles will be explained in more detail. When laminating copper foil and thermoplastic polyimide in a hot roll laminator, the copper foil and thermoplasticity are passed by passing between the hot and pressure press rolls of the hot roll laminator. Polyimide is bonded together. At the time of lamination, each material to be laminated is in a state of being expanded by heat, but generally, the linear expansion coefficient of thermoplastic polyimide is larger than the linear expansion coefficient of copper foil. Polyimide is thermally laminated with copper foil, and conversely, during cooling, the thermoplastic polyimide shrinks more in the surface direction than the copper foil. For this reason, the produced laminated board wrinkles in the surface direction. This is because the material retains heat immediately after the lamination when the pressure is released, and the temperature is higher than the Tg of the thermoplastic polyimide, so that the thermoplastic polyimide is in a fluid state and the generation of wrinkles cannot be suppressed. Also contributed.
[0007]
For the purpose of suppressing this wrinkle, a protective material that can withstand high temperatures during lamination, such as a polyimide film, is laminated between the pressure surface and the material to be laminated at the time of lamination. There is a method in which the laminate is not peeled off immediately from the laminated laminate, but is peeled off after the temperature of the laminate is below the Tg of the adhesive film. Although the thermoplastic polyimide after lamination tends to shrink, the use of the protective material by this method suppresses the movement of the laminated laminate in the surface direction, and further restricts the movement of the thermoplastic polyimide to cause wrinkles. Utilizing that does not occur. However, in this method, the adhesion between the protective material and the copper foil is important. For example, if the surface roughness of the copper foil on the protective material side is rough, the protective material and the copper foil peel off immediately after lamination, There was a problem of causing wrinkles in the laminate.
[0008]
[Means for Solving the Problems]
In view of the above-mentioned problems, the present invention provides a laminate suitable as a flexible substrate material free from defects in appearance such as wrinkles generated during thermal lamination.
[0009]
That is, the present inventors have found that a laminate having a good surface property can be produced regardless of the type of copper foil in which the surface roughness of the copper foil is different in the same system as described above.
[0010]
That is, the present invention is a method for producing a laminated plate in which a metal material is disposed on both sides of an adhesive film and is continuously bonded by a hot roll laminating apparatus, and between the pressing surface of the apparatus and the metal material. A protective material having a thermoplastic resin laminated on one side is placed so that the thermoplastic resin is in contact with the metal material, and after performing pressure heating molding at 200 ° C. or higher, the glass transition temperature of the adhesive film adhesive layer ( Tg) or less, and the protective material is peeled from the laminated plate in a range of 0.1 to 5 N / cm in adhesion strength between the protective material and the laminated material. As used herein, the protective material refers to a non-constituent material of the laminated board. When the adhesion strength is less than 0.1 N / cm, the non-laminate material cannot withstand the shrinkage and peels off to cause wrinkles. On the other hand, if it is higher than 5 N / cm, a stress is applied to the material to be laminated at the time of peeling, which causes an appearance problem such as curling. Furthermore, this invention is a manufacturing method of the laminated board characterized by using the adhesive film which contains 50 weight% or more of thermoplastic polyimide in an adhesive component as said adhesive film. Furthermore, this invention is a manufacturing method of the laminated board characterized by using the copper foil whose thickness is 50 micrometers or less as said metal material. Furthermore, this invention is a manufacturing method of the laminated board characterized by using a polyimide film as said protective material.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below.
[0012]
Although the use of the laminated board obtained by the manufacturing method of this invention is not specifically limited, It is mainly used as a flexible laminated board for electronic electricity.
[0013]
As the adhesive film, a single-layer film made of a resin having a heat-fusible property, a multi-layer film formed by forming a resin layer having a heat-fusible property on both sides of a core layer not having a heat-fusible property, paper, Examples include films in which a base material such as glass cloth is impregnated with a resin having heat-fusibility, but if a base material having rigidity such as glass cloth is used, the flexibility is inferior. For example, a single layer film made of a resin having a heat-fusible property and a multi-layer film formed by forming a resin layer having a heat-fusible property on both sides of a core layer not having a heat-fusible property are preferable. A single-layer film made of a resin having a heat-fusible property and a multi-layer film formed by forming a resin layer having a heat-fusible property on both sides of a core layer not having a heat-fusible property include those having heat resistance. Preferably, an adhesive component composed of a thermoplastic polyimide-based component, for example, a thermoplastic polyamideimide, a thermoplastic polyetherimide, a thermoplastic polyesterimide, or the like can be suitably used. An adhesive film containing 50% or more of these heat-resistant thermoplastic resins in the adhesive component is also preferably used in the present invention, and an adhesive film containing a thermosetting resin such as an epoxy resin or an acrylic resin can also be used. preferable. Various additives may be added to the adhesive film to improve various properties.
[0014]
The structure of the adhesive film may be a single layer composed only of a heat-fusible adhesive component as long as it has a heat-resistant adhesive layer on the outside, but it has heat-fusible properties from the viewpoint of dimensional characteristics and the like. A film having a three-layer structure having a heat-fusible adhesive layer on both sides of the core layer not to be used is preferable. The core layer having no heat-fusibility is not particularly limited as long as it has heat resistance, but it is preferable to use a non-thermoplastic polyimide film.
[0015]
Although it does not specifically limit about the preparation methods of an adhesive film, When it consists of an adhesive bond single layer, it can form into a film by a belt cast method, an extrusion method, etc. Further, when the adhesive film is composed of three layers of adhesive layer / core layer / heat-bonding layer having no heat-fusibility, both sides of the core layer (eg heat-resistant film) having no heat-fusibility are used. A method of producing a three-layer adhesive film by applying an adhesive one side at a time or both sides simultaneously, or a single-layer adhesive film consisting only of an adhesive component on both sides of a heat-resistant film and bonding them together There is a method for producing an adhesive film. In the method for producing a three-layer adhesive film by applying an adhesive, particularly when using a polyimide adhesive, a method of applying imidization while applying to a heat resistant film in a polyamic acid state and then drying There is a method in which a soluble polyimide resin is directly applied and dried, and the method for forming the adhesive layer is not particularly limited. In addition, there is a method of forming a heat-resistant adhesive film at a time by co-extrusion of each resin of the adhesive layer / core layer / adhesive layer not having heat-resistant fusion.
[0016]
Although it does not specifically limit as a metal material, In the case of the laminated board used for an electronic electrical apparatus, it is preferable to use copper foil from the point of electroconductivity and cost. Moreover, about the thickness of metal foil, since the line | wire width of a circuit pattern can be thinned, so that the thickness of copper foil is thin, copper foil of 50 micrometers or less is preferable. In particular, a copper foil having a thickness of 35 μm or less is less stiff than a copper foil having a thickness larger than that, and is likely to be wrinkled when thermally laminated. Therefore, the present invention exerts a remarkable effect on a copper foil having a thickness of 35 μm or less. In addition, examples of the copper foil include rolled copper foil, electrolytic copper foil, HTE copper foil and the like, and are not particularly limited, and an adhesive may be applied to these surfaces.
[0017]
The hot roll laminating apparatus is not particularly limited as long as it is an apparatus that heats and laminates a material to be laminated. The heating method is not particularly limited as long as it can be heated at a predetermined temperature, and examples thereof include a heat medium circulation method, a hot air heating method, and a dielectric heating method. The heating temperature is preferably 200 ° C. or higher. However, when the laminated plate is used for the purpose of passing through a solder reflow furnace having an atmospheric temperature of 240 ° C. for mounting electronic components, a heat-sealing film having a Tg corresponding thereto is used. Heating at 240 ° C. or higher is preferred for use. The material of the press roll is not particularly limited, such as rubber and metal, but when the laminating temperature reaches a high temperature of 280 ° C. or higher, the rubber roll is deteriorated and cannot be used, and a metal roll is preferable. The pressurization method is not particularly limited as long as a predetermined pressure can be applied, and includes a hydraulic method, a pneumatic method, a gap pressure method, and the like, and the pressure is not particularly limited.
[0018]
The protective material may be anything as long as it satisfies the purpose of protecting the laminated product from appearance defects such as wrinkles. However, it must be able to withstand the temperature during processing. For example, when processing at 250 ° C., a polyimide film having higher heat resistance is effective. The thickness of the protective material is not particularly limited, but a thickness of 50 μm or more is preferable for the purpose of suppressing wrinkle formation of the laminated board after lamination. It is preferable that the thickness of the protective material is 75 μm or more because wrinkle formation can be almost completely suppressed. More preferably, it is 125 μm or more.
[0019]
There is no problem if the protective material is a single film of polyimide or the like as long as it can be peeled in the range of 0.1 to 5 N / cm below the Tg of the adhesive film adhesive layer, and a resin showing adhesiveness at the time of lamination on one side of the protective material. You can also use it. For example, a thermoplastic resin having Tg near the laminating temperature can be considered. Usually, the lamination temperature when manufacturing a heat-resistant flexible laminate is as high as 200 ° C. or more, and heat resistant materials such as a thermoplastic polyimide resin, a thermoplastic polyamide resin, and a thermoplastic polyamideimide resin can withstand that temperature. A thermoplastic resin is effective.
[0020]
The method of forming the thermoplastic resin layer on one side of the protective material is not particularly limited as long as a resin having a predetermined resin structure is obtained, and a method of applying and drying the thermoplastic resin on one side of the protective material or a thermoplastic resin film in advance. And a method of forming a thermoplastic resin layer on one side at the same time when the protective material is prepared.
[0021]
The thickness of the thermoplastic resin formed on one side of the protective material is not particularly limited. However, if the thermoplastic resin layer is too thick, the thermoplastic resin layer may cohesively break when it is peeled off from the metal material, and can be transferred to the metal material. Therefore, a thickness of 10 μm or less is preferable. More preferably, it is 5 μm or less.
[0022]
When the thermoplastic resin is used as the material to be laminated, the temperature of the laminate when peeling the protective material is preferably a temperature equal to or lower than the Tg. More preferably, the temperature is 50 ° C. or more lower than Tg, and more preferably 100 ° C. or more lower than Tg. Most preferably, the protective material is peeled off from the laminate when cooled to room temperature.
[0023]
Hereinafter, the present invention will be described in more detail with reference to examples.
[0024]
【Example】
In the examples, the glass transition temperature (Tg) was measured by Shimadzu DSC CELL SCC-41 (differential scanning calorimeter) in a temperature range from room temperature to 400 ° C. at a heating rate of 10 ° C./min under a nitrogen stream. It was measured.
[0025]
(Reference Example 1) Good surface properties on both sides of a 25 μm-thick three-layer adhesive film (PIXEO-BP manufactured by Kaneka Chemical Co., Ltd.) having a thermoplastic polyimide resin component having a Tg of 190 ° C. on both sides of the non-thermoplastic polyimide film 18 μm electrolytic copper foil (center surface average roughness Rz = 0.79 μm on the glossy surface), and a 125 μm polyimide film (Apical 125NPI manufactured by Kaneka Chemical Co., Ltd.) as a protective film on both sides And then laminating under the conditions of 360 ° C, L / S 2.0m / min, linear pressure 500N / cm with a hot roll laminator, cooling to room temperature, peeling off the protective film from the flexible laminate and flexible A laminate was prepared. The adhesion strength between the protective film and the flexible laminate at this time was 0.5 N / cm. As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0026]
(Example 1) An 18 μm-thick electrolytic copper foil having a good surface property (center line average roughness Rz = 0.79 μm) on both sides of the adhesive film having a three-layer structure used in Reference Example 1 Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) coated with 2 μm thermoplastic resin (Tg 340 ° C.) on one side as a protective film is arranged on both sides, and a heat roll laminator (temperature 360 ° C.). , L / S 2.0 m / min, linear pressure 500 N / cm), and then cooled to 150 ° C., and the protective film was peeled from the flexible laminate to produce a flexible laminate. At this time, the adhesion strength between the protective film and the flexible laminate was 1.5 N / cm. As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0027]
(Example 2) An 18 μm-thick electrolytic copper foil having a good surface property (center line average roughness Rz = 0.79 μm) on both sides of the adhesive film having a three-layer structure used in Reference Example 1 Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) coated with 2 μm thermoplastic resin (Tg 340 ° C.) on one side as a protective film is arranged on both sides, and a heat roll laminator (temperature 360 ° C.). , L / S 2.0 m / min, linear pressure 500 N / cm), and then cooled to room temperature, and the protective film was peeled from the flexible laminate to produce a flexible laminate. The adhesion strength between the protective film and the flexible laminate at this time was 2 N / cm. As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0028]
(Example 3) An 18 μm-thick electrolytic copper foil having a poor surface property (center line average roughness Rz = 1.84 μm on the glossy surface) is arranged on both sides of the adhesive film having a three-layer structure used in Reference Example 1. Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) coated with 2 μm thermoplastic resin (Tg 340 ° C.) on one side as a protective film is arranged on both sides, and a heat roll laminator (temperature 360 ° C.). , L / S 2.0 m / min, linear pressure 500 N / cm), and then cooled to 150 ° C., and the protective film was peeled from the flexible laminate to produce a flexible laminate. The adhesion strength between the protective film and the flexible laminate at this time was 1 N / cm. As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0029]
(Example 4) An 18 μm-thick electrolytic copper foil having a poor surface property (centerline average roughness Rz = 1.84 μm on the surface of the glossy surface) is disposed on both sides of the adhesive film having a three-layer structure used in Reference Example 1. Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) coated with 2 μm thermoplastic resin (Tg 340 ° C.) on one side as a protective film is arranged on both sides, and a heat roll laminator (temperature 360 ° C.). , L / S 2.0 m / min, linear pressure 500 N / cm), and then cooled to room temperature, and the protective film was peeled from the flexible laminate to produce a flexible laminate. At this time, the adhesion strength between the protective film and the flexible laminate was 1.5 N / cm. As a result, a flexible laminated board free from defects such as wrinkles was obtained.
[0030]
(Comparative Example 1) An 18 μm-thick electrolytic copper foil having a good surface property (centerline average roughness Rz = 0.79 μm on the glossy surface) is disposed on both sides of the three-layer adhesive film used in Reference Example 1. Further, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) coated with 2 μm thermoplastic resin (Tg 200 ° C.) on one side as a protective film is arranged on both sides, and a heat roll laminator (temperature 360 ° C.). , L / S 2.0 m / min, linear pressure 500 N / cm), and then cooled to room temperature, and the protective film was peeled from the flexible laminate to produce a flexible laminate. The adhesion strength between the protective film and the flexible laminate at this time was 7 N / cm. As a result, only a flexible laminate having a large curl was obtained.
[0031]
(Comparative Example 2) An 18 μm-thick electrolytic copper foil (center line average roughness Rz = 1.84 μm on the surface of the glossy surface) having a poor surface property is arranged on both sides of the adhesive film having a three-layer structure used in Reference Example 1. Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) is arranged on both sides as a protective film, and a heat roll laminating machine (temperature 360 ° C., L / S 2.0 m / min, linear pressure 500 N / cm). ) And then cooled to room temperature, and the protective film was peeled from the flexible laminate to produce a flexible laminate. However, the protective film and the flexible laminate were peeled off and wrinkled. As a result, only a flexible laminate having a wrinkled appearance was obtained.
[0032]
(Comparative Example 3) An 18 μm-thick electrolytic copper foil (center line average roughness Rz = 1.84 μm on the surface of the glossy surface) having a poor surface property is arranged on both sides of the adhesive film having the three-layer structure used in Reference Example 1. Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) is arranged on both sides as a protective film, and a heat roll laminating machine (temperature 360 ° C., L / S 2.0 m / min, linear pressure 500 N / cm). Then, the laminate was cooled to 150 ° C., and the protective film was peeled off from the flexible laminate to produce a flexible laminate. However, the protective film and the flexible laminate were peeled off and wrinkled. As a result, only a flexible laminate having a wrinkled appearance was obtained.
[0033]
(Comparative Example 4) An 18 μm-thick electrolytic copper foil (center line average roughness Rz = 0.79 μm on the surface of the glossy surface) having good surface properties is arranged on both sides of the adhesive film having a three-layer structure used in Reference Example 1. Furthermore, a 125 μm polyimide film (Apical 125 NPI manufactured by Kaneka Chemical Co., Ltd.) is arranged on both sides as a protective film, and a heat roll laminating machine (temperature 360 ° C., L / S 2.0 m / min, linear pressure 500 N / cm). Then, the laminate was cooled to 250 ° C., and the protective film was peeled off from the flexible laminate to produce a flexible laminate. As a result, only a flexible laminate having a wrinkled appearance was obtained.
[0034]
【The invention's effect】
A method of manufacturing a laminated board in which a metal material is disposed on both sides of an adhesive film and is continuously bonded by a hot roll laminating apparatus, and is thermoplastic on one side between the pressing surface of the apparatus and the metal material . A protective material laminated with a resin is disposed so that the thermoplastic resin is in contact with the metal material, and after performing pressure heating molding at 200 ° C. or higher, the glass transition temperature (Tg) of the adhesive film adhesive layer is lower than When the adhesion strength between the protective material and the material to be laminated is in the range of 0.1 to 5 N / cm, the protective material is peeled from the laminated plate to obtain a laminated plate having a good appearance regardless of the surface roughness of the copper foil. I can do it. Accordingly, the present invention provides a material suitable as a flexible laminate for electronic and electronic equipment.

Claims

A method of manufacturing a laminated board in which a metal material is disposed on both sides of an adhesive film and is continuously bonded by a hot roll laminating apparatus, and is thermoplastic on one side between the pressing surface of the apparatus and the metal material . A protective material laminated with a resin is disposed so that the thermoplastic resin is in contact with the metal material, and after performing pressure heating molding at 200 ° C. or higher, the glass transition temperature (Tg) of the adhesive film adhesive layer is lower than A method for producing a laminated board, comprising peeling off the protective material from the laminated board so that the adhesion strength between the protective material and the laminated material is in the range of 0.1 to 5 N / cm.

The method for producing a laminated board according to claim 1, wherein an adhesive film containing 50% by weight or more of thermoplastic polyimide in an adhesive component is used as the adhesive film.

The method for manufacturing a laminated board according to claim 1, wherein a copper foil having a thickness of 50 μm or less is used as the metal material.

The method for manufacturing a laminated board according to any one of claims 1 to 3, wherein a polyimide film is used as the protective material.