JP4560697B2 - Flexible metal laminate and manufacturing method thereof - Google Patents

Description

（式中、Ｒ１およびＲ２は同じであっても異なっていてもよく、それぞれ水素もしくは炭素数１〜４のアルキル基を示す。）
【０００８】
【化４】

（１３）（６）〜（１２）のいずれかに記載の方法により製造されるフレキシブル金属積層体。
【０００９】
【発明の実施の形態】
本発明で用いる耐熱性樹脂は金属箔と同等の熱膨張係数を有し、耐熱性に優れるものであれば基本的にはどのような樹脂を用いてもよいが、好ましくは重縮合反応により得られる芳香族ポリイミド及び／又は芳香族ポリアミドイミドである。芳香族ポリイミドや芳香族ポリアミドイミドの製造は通常の方法で合成することができ、例えば、イソシアネート法、酸クロリド法、低温溶液重合法、室温溶液重合法などである。
【００１０】
芳香族ポリイミドに用いる原料としては、以下に示す様なものがあげられる。酸成分としては、ピロメリット酸、ベンゾフェノン−３、３’、４、４’−テトラカルボン酸、ビフエニル−３，３’、４、’ーテトラカルボン酸、ジフェニルスルホン３、３’、４、４’−テトラカルボン酸、ジフェニルエーテル−３，３’、４、４’−テトラカルボン酸、ナフタレン−２、３、６、７ーテトラカルボン酸、，ナフタレン−１、２、４、５−テトラカルボン酸、ナフタレン−１、４、５、８−テトラカルボン酸などの一無水物、二無水物、エステル化物などが単独、或いは２種以上の混合物として用いることができる。また、アミン成分としてはＰ−フェニレンジアミン、ｍ−フェニレンジアミン、３、４’−ジアミノジフェニルエーテル、４、４’−ジアミノジフェニルエーテル、４、４’−ジアミノジフェニルスルホン、３、３’−ジアミノジフェニルスルホン、３、４’−ジアミノビフエニル、３、３’−ジアミノビフエニル、３，３’−ジアミノベンズアニリド、４，４’−ジアミノベンズアニリド、４、４’−ジアミノベンゾフエノン、３、３’−ジアミノベンゾフエノン、３、４’−ジアミノベンゾフエノン、２、６−トリレンジアミン、２、４−トリレンジアミン、４、４’−ジアミノジフェニルスルフィド、３、３’−ジアミノジフェニルスルフィド、４、４’−ジアミノジフェニルプロパン、３、３’−ジアミノジフェニルプロパン、４、４’−ジアミノジフェニルヘキサフルオロプロパン、３、３’−ジアミノジフェニルヘキサフルオロプロパン、３、３’−ジアミノジフェニルメタン、４、４’−ジアミノジフェニルメタン、４、４’−ジアミノジフェニルヘキサフルオロイソプロピリデン、Ｐ−キシレンジアミン、ｍ−キシレンジアミン、１，４−ナフタレンジアミン、１，５−ナフタレンジアミン、２，６−ナフタレンジアミン、２，７−ナフタレンジアミン、Ｏ−トリジン、２、２’−ビス（４−アミノフェニル）プロパン、２、２’−ビス（４−アミノフェニル）ヘキサフルオロプロパン、１，３−ビス（３−アミノフェノキシ）ベンゼン、１，３−ビス（４−アミノフェノキシ）ベンゼン、１，４−ビス（４−アミノフェノキシ）ベンゼン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン、ビス［４−（４−アミノフェノキシ）フェニル］スルホン、ビス［４−（３−アミノフェノキシ）フェニル］スルホン、ビス［４−（３−アミノフェノキシ）フェニル］プロパン、ビス［４−（３−アミノフェノキシ）フェニル］ヘキサフルオロプロパン、４，４’−ビス（４−アミノフェノキシ）ビフェニル、４，４’−ビス（３−アミノフェノキシ）ビフェニル、２、２−ビス［４−（４−アミノフェノキシ）フエニル］ヘキサフルオロプロパン、或いはこれらに対応するジイソシアネートなどの単独或いは２種以上の混合物を用いることができる。また、これら酸成分、アミン成分の組み合わせで別途重合した樹脂を混合して使用することもできる。
【００１１】
芳香族ポリアミドイミドに用いる原料としては、酸成分としてトリメリット酸無水物、ジフエニルエーテル−３、３’、４’−トリカルボン酸無水物、ジフエニルスルホン−３、３’、４’−トリカルボン酸無水物、ベンゾフェノン−３、３’、４’−トリカルボン酸無水物、ナフタレン、１，２、４−トリカルボン酸無水物などのトリカルボン酸無水物類が単独或いは混合物として、アミン成分としてはポリイミド同様のジアミン、或いはジイソシアネートの単独、或いは混合物があげられる。また、これら酸成分、アミン成分の組み合わせで別途重合した樹脂を混合して使用することもできる。
【００１２】
耐熱性や耐薬品性、耐アルカリ性、熱膨張係数（寸法変化率）、巻物状での成形加工性、及び製造コストなどの面から特に好ましい耐熱性樹脂は有機溶剤に可溶な芳香族ポリイミド、芳香族ポリアミドイミドで、より好ましくは下記一般式（１）、或いは（２）で示される構造単位を含有する芳香族ポリアミドイミドである。
【化５】

（式中、Ｒ１、Ｒ２は同じであっても異なっていてもよく、それぞれ、水素もしくは炭素数１〜４のアルキル基を示す。）
【００１３】
【化６】

【００１４】
本発明で用いる耐熱性樹脂溶液の溶媒としては、Ｎ−メチル−２ーピロリドン、Ｎ、Ｎ’−ジメチルホルムアミド、Ｎ、Ｎ’−ジメチルアセトアミド、１、３−ジメチル−２−イミダゾリジノン、テトラメチルウレア、スルホラン、ジメチルスルホオキシド、γ−ブチロラクトン、シクロヘキサノン、シクロペンタノンなどで、好ましくはＮ−メチル−２−ピロリドンである。また、これらの一部をトルエン、キシレンなどの炭化水素系有機溶剤、ジグライム、トリグライム、テトラヒドロフランなどのエーテル系有機溶剤、メチルエチルケトン、メチルイソブチルケトンなどのケトン系有機溶剤で置き換えることも可能である。
【００１５】
本発明で用いられる耐熱性樹脂の分子量は、Ｎ−メチル−２−ピロリドン中、３０℃での対数粘度にして０．３から２．５ｄｌ／ｇにあるものが好ましく、より好ましくは１．０から２．０ｄｌ／ｇである。対数粘度が０．３ｄｌ／ｇ以下では折り曲げ性や基材の端裂抵抗などの機械的特性が不十分であり、また、２．０ｄｌ／ｇ以上では接着強度が不足し、又、溶液粘度が高くなる為、成形加工が困難となる。
【００１６】
また、本発明で用いる芳香族ポリイミド、芳香族ポリアミドイミドにおいて耐熱性や熱膨張係数を損なわない範囲で、酸成分としてアジピン酸、アゼライン酸、セバシン酸、シクロヘキサン−４，４，’−ジカルボン酸、ブタン−１，２，４−トリカルボン酸、ブタン−１，２，３，４−テトラカルボン酸、シクロペンタン−１，２、３，４−テトラカルボン酸などの脂肪族や脂環族のジカルボン酸、ポリカルボン酸、及びこれらの一無水物や二無水物、エステル化物などを、又、アミン成分として、テトラメチレンジアミン、ヘキサメチレンジアミン、イソホロンジアミン、４、４’−ジシクロヘキシルメタンジアミン、シクロヘキサン−１，４−ジアミン、ジアミノシロキサンなどの脂肪族や脂環族ジアミン或いはこれらに対応するジイソシアネートを単独あるいは２種以上の混合物として用いても良い。また、これら酸成分、アミン成分の組み合わせで別途重合した樹脂を混合して使用することもできる。
【００１７】
本発明において、金属箔に耐熱性樹脂溶液を塗布、乾燥（以下初期乾燥工程）した後、巻き取り、巻物状で熱処理・乾燥（以下、熱処理・脱溶剤工程）して、フレキシブル金属積層体を製造するに際し、初期乾燥後の残存溶剤量、即ち、巻物状で熱処理・脱溶剤する際の残存溶剤量は少なくとも１０重量％は必要であり、できるだけ多い方がカールの少ないフレキシブルプリント配線板を製造することができる。残存溶剤量とは塗布、初期乾燥後の溶剤を含んだ樹脂系中の溶剤量をさし、実施例に示す数式〔数２〕で表されるものである。残存溶剤量が１０重量％より少ないと、本発明の処理条件においては、溶剤の体積収縮に伴う内部応力を緩和することができず、基板のカールをなくすことはできない。
【００１８】
又、残存溶剤量の多い方が、金属積層体のカールは少なくなるが、逆に多すぎると巻き取り時、塗布した樹脂層が流れ出したり、粘着したりするので好ましくない。樹脂の種類にもよるが、巻き取り時の残存溶剤量の上限は、４０重量％、好ましくは、３０重量％である。
【００１９】
初期乾燥は、耐熱性樹脂溶液に使用する溶媒の沸点より７０℃から１３０℃低い温度で行う必要がある。乾燥温度が（摂氏で表した溶媒の沸点の数値部分−７０）℃より高いと、残存溶剤量が１０重量％以上にしても、樹脂層の厚み方向での残溶剤のムラが大きくなり、特に樹脂表層の残溶剤量が少なくなるため、後の巻物状での緩和が不十分になり基材にカールが発生する。又、（摂氏で表した溶媒の沸点の数値部分−１３０）℃より低いと乾燥時間が長くなり、生産性が低下する。
【００２０】
初期乾燥方式はロールサポート方式やフローティング方式など、従来公知の方法で行うことができる。また、塗工方法としては、特に限定されるものではなく、従来からよく知られている方法を適用させることができる。ロールコーター、ナイフコーター、ドクター、ブレードコーター、グラビアコーター、ダイコーター、リバースコーターなどにより、塗工液の粘度を調整後、金属箔に直接塗布することができる。適性な溶液粘度としては、２５℃でのＢ型粘度で１から１０００ポイズの範囲である。又、塗工に際しては、後に説明する巻物状での加工性を上げる為、金属箔の両端部に未塗工部を残すと好ましい。
【００２１】
本発明において熱処理・脱溶剤時の雰囲気は減圧下、及び／又は不活性ガス雰囲気中で行う必要がある。空気中で行うと樹脂層が劣化、或いは過度に架橋し、基材のカールが大きくなったり、樹脂層の機械的特性が損なわれる。また、Ｎ−メチル−２−ピロリドンなどの溶剤が所定量残っている状態で空気中や酸素が存在する雰囲気で熱処理すると、樹脂層の機械的特性のみではなく、樹脂層と金属箔との接着性が低下する。好ましくは２ｍｍＨｇ程度以下の減圧下、或いは、減圧下で残溶剤率を５重量％以下にしてから、不活性ガス雰囲気中で熱処理する必要がある。より好ましくは、塗布した樹脂層の不溶率を２０％以下に保ちながら減圧下で残溶剤率を５重量％以下にし、次いで不活性ガス雰囲気中、さらに高温で熱処理することでカールのない耐熱性に優れるフレキシブル金属積層体を得ることができる。
【００２２】
不溶率とは、基材を熱処理・脱溶剤後、金属箔を除いた部分の樹脂層のみをＮ−メチル−２−ピロリドン中０．５重量％濃度の溶液で１００℃、２時間溶解した後の樹脂層の不溶分を示し、実施例で示す数式〔数４〕で示されるものである。
【００２３】
熱処理・脱溶剤時の温度や時間の条件は、熱処理・脱溶剤工程終了後、塗布した樹脂層の不溶率が１％〜９９％、好ましくは、５％〜８５％になる範囲で行う。不溶率が１％以下では、半田耐熱などの耐熱性や耐薬品性、特に耐アルカリ性が不十分であり、９９％以上では基材のカールが大きくなる。具体的には（摂氏で表した耐熱性樹脂のガラス転移点の数値部分−２５０）℃の温度から（摂氏で表した耐熱性樹脂のガラス転移点の数値部分＋５０）℃の温度で行う。
【００２４】
溶剤の体積収縮に伴って発生する内部応力を巻物状で緩和させながら完全に脱溶剤させるという本発明の趣旨からすると、より高い温度好ましくは溶剤を含まない耐熱性樹脂のガラス転移点より高い温度で熱処理すれば、有効に応力緩和できるということになるが、温度が高すぎると逆に、樹脂が架橋反応しすぎたり劣化反応したりする為、内部ひずみは大きくなり基材のカールは大きくなる。この温度は使用する耐熱性樹脂の種類、即ち、長期耐熱性によるが、本発明においては（摂氏で表した耐熱性樹脂のガラス転移点の数値部分＋５０）℃の温度以下にする必要がある。又、熱処理・脱溶剤温度が（摂氏で表した耐熱性樹脂のガラス転移点の数値部分−２５０）℃より低いと基材のカール矯正や不溶率を上げる為の架橋反応に長時間を要し、生産性が低下する。
【００２５】
本発明においては、溶剤を残した状態で巻き取り、後に熱処理して完全に脱溶剤する為、樹脂溶液の塗布面と非塗布面が接触しない様に巻き取る必要がある。接触しない様にするには、ゆる巻きにしたり、或いは、樹脂溶液を塗布した塗布面を外側にし、積層物に該積層物とは異なる素材のテープをはさみ込む。テープをはさみ込む位置に特に限定はないが、好ましくは、塗布面の樹脂溶液を塗布していない部分に（塗布面両端の未塗工部分）にはさみ込むか、或いは、より好ましくは図−１のごとき積層物両端部の表裏をテープで包み込む様にして巻き取る。テープの素材は熱処理・脱溶剤温度で収縮や軟化、溶融などによって変形しないものを選択すればよいが、好ましくはセルロース、ガラス、カーボン、アラミドなどから作られる織布や不織布などのテープである。テープの厚みは樹脂溶液の塗布厚以上が必要であり、塗布厚以下では、特に残溶剤量が高いと塗布面と非塗布面が接触するため生産性が低下する。又、テープの幅は、５〜１００ｍｍ程度である。５ｍｍ以下では、特に包み込む場合に作業性が悪くなり、又、１００ｍｍ以上では、脱溶剤効率が悪くなったり、或いは塗工部分に接触する面積が大きくなる為（或いは、未塗工幅を長くとる必要がある為）、塗工面の外観不良などにより収率が低くなる。
【００２６】
本発明に用いる金属箔としては、銅箔、アルミニウム箔、スチール箔、及びニッケル箔などを使用することができ、これらを複合した複合金属箔や亜鉛やクロム化合物など他の金属で処理した金属箔についても用いることができる。金属箔の厚みについては特に限定はないが、たとえば、３から５０μｍの金属箔を好適に用いることができる。
【００２７】
また、本発明においては、フレキシブル金属積層体の諸特性、たとえば、機械的特性、電気的特性、滑り性、難燃性などを改良する目的で他の樹脂や有機化合物、及び無機化合物を混合させたり、あるいは反応させて併用してもよい。たとえば、滑剤（シリカ、タルク、シリコーン等）、接着促進剤、難燃剤（リン系やトリアジン系、水酸化アルミ等）、安定剤（酸化防止剤、紫外線吸収剤、重合禁止剤等）、メッキ活性化剤、有機や無機の充填剤（タルク、酸化チタン、フッ素系ポリマー微粒子、顔料、染料、炭化カルシウム等）、その他、シリコーン化合物、フッ素化合物、イソシアネート化合物、ブロックイソシアネート化合物、アクリル樹脂、ウレタン樹脂、ポリエステル樹脂、ポリアミド樹脂、エポキシ樹脂、フェノール樹脂のような樹脂や有機化合物、或いはこれらの硬化剤、酸化珪素、酸化チタン、炭酸カルシウム、酸化鉄などの無機化合物をこの発明の目的を阻害しない範囲で併用することができる。
【００２８】
【実施例】
以下、実施例により、この発明をさらに詳しく説明する。なお、本発明は実施例により、特に制限されるものではない。各実施例における特性値の評価方法は以下の通りである。
【００２９】
対数粘度
ポリマー濃度が０．５ｇ／ｄｌとなるようにＮ−メチル−２−ピロリドンに溶解し、その溶液の溶液粘度及び溶媒粘度を３０℃で、ウベローゼ型の粘度管により測定して、下記の式で計算した。
【００３０】
【数１】

【００３１】
ガラス転移点
ＴＭＡ（熱機械分析／理学株式会社製）引張荷重法により本発明のフレキシブル金属積層体の金属箔をエッチング除去した樹脂フィルム層のガラス転移点を以下の条件で測定した。なおフィルムは、窒素中、昇温速度１０℃／分で、一旦、変曲点まで昇温し、その後室温まで冷却したフィルムについて測定を行った。
荷重：１ｇ
サンプルサイズ：４（幅）×２０（長さ）ｍｍ
昇温速度：１０℃／分
雰囲気：窒素
【００３２】
残存溶剤率
ＪＩＳ Ｋ５４００により、２５０℃×１時間の乾燥条件で以下の式より計算した。（金属積層体の残存溶剤率については、２５０℃×１ｈｒで絶乾後、金属箔をエッチング法により除去することで金属箔の重量を求め、絶乾前の金属積層体重量から金属箔の重量をひき〔樹脂＋溶剤〕の重量を算出し、又、金属積層体の絶乾前後の重量変化から溶剤重量をそれぞれ求め、数式数〔３〕より求めた。）
【数２】

【００３３】
【数３】

【００３４】
不溶率
成形されたフレキシブル金属積層板の金属箔をエッチング除去した樹脂フィルム層の０．５重量％Ｎ−メチル−２−ピロリドン溶液を１００℃×２時間加熱処理し、不溶分を下記の式により計算した。
【数４】

【００３５】
基板のカール
フレキシブル金属積層板のカールの曲率半径を求めた（サンプルサイズ；１０ｃｍ×１０ｃｍ）。
【００３６】
半田耐熱
フレキシブル金属積層板の金属箔をサブトラクティブ法によりエッチング加工し、幅１ｍｍの回路パターンを作成したサンプルを４０℃、８５％（湿度）で５時間調湿しフラックス洗浄した後、３５０℃で半田付けを行い、顕微鏡で剥がれや膨れの有無を観察した。
【００３７】
寸法変化率
ＩＰＣ−ＦＣ２４１で１５０℃×３０分と２００℃×３０分、及び２５０℃×３０分の条件で、ＭＤ方向とＴＤ方向について測定した。
【００３８】
接着強度
ＩＰＣ−ＦＣ２４１でサブトラクティブ法により幅１ｍｍの回路パターンを作成したサンプルを引張速度５０ｍｍ／分、引き剥がし角度９０°で測定した。
【００３９】
端裂抵抗
金属箔をエッチング除去した樹脂フィルムから幅２０ｍｍ、長さ２００ｍｍのサンプルを作成し、ＪＩＳ−Ｃ２３１８で測定した。
【００４０】
樹脂フィルムの強度、伸度、弾性率
金属箔をエッチング除去した樹脂フィルムから、幅１０ｍｍ、長さ１００ｍｍのサンプルを作成し、テンシロン引張試験機にて、以下の条件で測定した。
サンプル調湿：４０℃、８５％（湿度）×５時間
引張速度２０ｍｍ／分
チャック間距離４０ｍｍ
【００４１】
樹脂フィルムの耐アルカリ性試験
４０重量％の水酸化ナトリウム水溶液に金属箔をエッチング除去した耐熱性樹脂フィルムを１００時間浸漬し、浸漬後、十分に水洗・乾燥したサンプルの弾性率を上記の条件で測定した。次いで、浸漬前後の弾性率から、その保持率を求めた。
【数５】

【００４２】
耐屈曲性
金属箔をエッチング除去した幅１０ｍｍの耐熱性樹脂フィルムをＪＩＳ Ｃ ５０１６により、荷重５００ｇ、屈曲径０．３８ｍｍで測定、フィルムが破断するまでの屈曲回数を求めた。
【００４３】
合成例１ 樹脂Ａの合成
反応容器に無水トリメリット酸１９２ｇ（三菱瓦斯化学株式会社製）、３、３‘−ジメチル−４、４’−ビフェニルジイソシアネート（日本曹達株式会社製、Ｏ−トリジンジイイソシアネート）２１１ｇ（８０モル％）、２，４−トリレンジイソシアネート（日本ポリウレタン株式会社製、コロネートＴ−１００）３５ｇ（２０モル％）、ナトリウムメチラート（和光株式会社製）０．５ｇ、及びＮ−メチル−２−ピロリドン（三菱化学株式会社製）２．５ｋｇを加え、１５０℃まで１ｈｒで昇温し、さらに１５０℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．６でガラス転移点は３２０℃であった。
【００４４】
合成例２ 樹脂Ｂの合成
反応容器に無水トリメリット酸１９２ｇ、１，５−ナフタレンジイソシアネート（住友バイエルウレタン株式会社製、デスモジュール１５）１５７ｇ（７５モル％）、４、４’−ジフェニルメタンジイソシアネート（住友バイエルウレタン株式会社製）６３ｇ（２５モル％）、ジアザビシクロウンデセン（株式会社サンアプロ製）１ｇ、及びＮ−メチル−２−ピロリドン２ｋｇを加え、１７０℃まで１ｈｒで昇温して、さらに１７０℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．４でガラス転移点は３５６℃であった。
【００４５】
合成例３ 樹脂Ｂ−１の合成
反応容器に無水トリメリット酸３８４ｇ、１，５−ナフタレンジイソシアネート３７８ｇ（９０モル％）、４、４’−ジフェニルメタンジイソシアネート５０ｇ（１０モル％）、フッ化カリウム（東京化成株式会社製）２．５ｇ、及びＮ−メチル−２−ピロリドン２ｋｇを加え、１３０℃まで１ｈｒで昇温して、さらに１３０℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．７でガラス転移点は３８１℃であった
【００４６】
合成例４ 樹脂Ｂ−２の合成
反応容器に無水トリメリット酸３８４ｇ、１，５−ナフタレンジイソシアネート３９９ｇ（９５モル％）、４、４’−ジフェニルメタンジイソシアネート２５ｇ（５モル％）、フッ化カリウム２．５ｇ、及びＮ−メチル−２−ピロリドン２ｋｇを加え、１００℃まで１ｈｒで昇温して、さらに１００℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．８でガラス転移点は３９０℃であった
【００４７】
合成例５ 樹脂Ｂ−３の合成
反応容器に無水トリメリット酸３８４ｇ、１，５−ナフタレンジイソシアネート２１０ｇ（５０モル％）、４、４’−ジフェニルメタンジイソシアネート２５１ｇ（５０モル％）、フッ化カリウム２．５ｇ、及びＮ−メチル−２−ピロリドン１．５ｋｇを加え、１５０℃まで１ｈｒで昇温して、さらに１５０℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．２でガラス転移点は３６７℃であった
【００４８】
合成例６ 樹脂Ａ−１の合成
反応容器に無水トリメリット酸１９２ｇ、３、３‘−ジメチル−４、４’−ビフェニルジイソシアネート２５１ｇ（９５モル％）、２，４−トリレンジイソシアネート８．７ｇ（５モル％）、ナトリウムメチラート０．５ｇ、及びＮ−メチル−２−ピロリドン２．５ｋｇを加え、１５０℃まで１ｈｒで昇温して、さらに１５０℃で５ｈｒ反応させた。得られたポリマーの対数粘度は、１．７でガラス転移点は３１５℃であった。
【００４９】
実施例、比較例
合成例で得られた樹脂溶液を１８μｍ圧延銅箔の処理面にコンマコーターを用いて、両端部を１ｃｍ程度残し（塗工せずに）脱溶剤後の厚みが２０μｍになるように連続的にコーテイングした。次いで、長さ２０ｍのフローテイング方式の乾燥炉に、表−１の乾燥条件になるよう、ライン速度を設定し、連続的に通過させた。得られた金属積層板の残存溶剤率は表−１に示す値であった。
このようにして得られた長尺状積層物に実施例１〜８、及び比較例においては、その塗布面の両端に幅が１ｃｍ、厚みが２００μｍのガラスクロス製のテープを挟み込み直径３インチのアルミニウム管に巻き取った。又、実施例９〜１１においては、長尺状積層物両端の非塗布面に、幅が１ｃｍ、厚みが３００μｍのガラスクロス製のテープを挟み込み、直径３インチのアルミニウム管に巻き取った。又、実施例１２においては、図−１のごときテープを包み込む形にし、塗布面が外側になるように、直径３インチのアルミニウム管に巻き取った。
次いで、巻き取ったロールを真空乾燥機、或いはイナートオーブンに入れ、表−１に示す熱処理・脱溶剤条件で加熱処理した。得られたフレキシブル金属積層体の塗膜中の溶剤は完全に除去されており、特性は表ー２、表−３に示すごときものであった。
【００５０】
【表１】

【００５１】
【表２】

【００５２】
【表３】

【００５３】
【発明の効果】
上述したように、本発明のフレキシブル金属積層体は、金属箔に耐熱性樹脂溶液を塗布、乾燥した後、一旦巻き取り、さらに脱溶剤しながら熱処理している為、カールや寸法変化率に優れ、耐熱性、耐薬品性（特に耐アルカリ性）にも優れる為、工業的に有用である。
【図面の簡単な説明】
【図１】本発明の金属箔積層体の巻き取り状態の概略図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flexible metal laminate for use in a flexible printed circuit board excellent in dimensional stability, heat resistance, chemical resistance (particularly alkali resistance) and adhesion, and a method for producing the same. More specifically, a flexible metal laminate having excellent dimensional stability, heat resistance, chemical resistance, and adhesiveness obtained by continuously applying a heat resistant resin solution to a metal foil, initially drying, and then heat-treating in a scroll shape, and its It relates to a manufacturing method.
[0002]
[Prior art]
A conventional flexible metal laminate for a flexible printed circuit board is obtained by bonding a polyimide film and a metal foil with a thermosetting adhesive such as an epoxy resin or an acrylic resin. The flexible printed circuit board bonded with this thermosetting adhesive has extremely poor adhesive thermal performance compared to the performance of polyimide film, so its application to chip-on-flex is limited. ”And“ peeling ”. In addition, if a thermal history such as thermocompression bonding is applied during processing, the substrate may be curled or twisted, and subsequent punching processing becomes impossible.
[0003]
In order to solve these problems, techniques for forming a metal foil directly on an insulating substrate without an adhesive have been studied. For example, Japanese Patent Laid-Open No. 02-98994 discloses a metal film by sputtering on a polyimide film, Japanese Patent Laid-Open No. 62-181488 by vapor deposition, and Japanese Patent Laid-Open No. 57-18357 by ion plating. There has been proposed a technique for forming a circuit pattern after forming the pattern. However, each method has a drawback that the manufacturing cost is high, and there is a problem that the adhesion between the polyimide film and the conductor is insufficient. That is, there is a drawback that pattern peeling occurs in the electrolytic plating process on the pattern for the purpose of increasing the strength of the formed pattern, or that the adhesion between the conductor and the polyimide film is lowered when exposed to a temperature of about 100 ° C. for a long time. there were.
[0004]
In order to form a flexible printed circuit board without an adhesive layer at a lower cost, in Japanese Patent Application Laid-Open Nos. 57-50670, 57-66690, and 60-15728, a polyimide-based solution is used. A method of directly applying to metal foil has been proposed. However, the flexible metal laminate obtained by such a method has a problem that the substrate curls with the resin layer on the inside due to the volumetric shrinkage of the solvent or the difference in thermal expansion coefficient between the resin and the copper foil. was there. In order to correct such curl, Japanese Patent Application Laid-Open No. 55-75289, Japanese Patent Application Laid-Open No. 54-111673, Japanese Patent Application Laid-Open No. 54-31480, etc., heat treatment at high temperature, stretching of the substrate during drying and curing. Although methods such as treatment or heat treatment by wrapping around a cylindrical drum have been studied, both methods have insufficient curl correction, and when continuous production is performed, productivity decreases or expensive equipment Therefore, the manufacturing cost is also high. Furthermore, the above-described method of directly applying and drying a polyimide-based solution has insufficient alkali resistance, and thus has many uses that cannot be applied as a flexible printed wiring board, such as an inkjet printer.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems, and by applying a heat-resistant resin solution directly to a metal foil and drying, heat resistance, dimensional stability, adhesion, chemical resistance, alkali resistance The metal laminate for a flexible printed circuit board that is excellent in the above and has no curl is to be manufactured at low cost.
[0006]
[Means for solving the problems]
As a result of diligent research to achieve the above object, the present inventors have continuously applied a heat resistant resin solution to a metal foil and dried it to produce a flexible metal laminate, leaving a certain amount of solvent or more. As it is, it is wound up, and further heat-treated while controlling the cross-linking reaction between the solvent and the resin, so that it has excellent characteristics such as heat resistance, dimensional stability, chemical resistance, and adhesiveness, and also has excellent alkali resistance. We have found that flexible metal laminates without curling can be manufactured at low cost. That is, the present invention has the following configuration.
(1) Flexible in which a heat-resistant resin film layer obtained from a condensation polymer is formed on one surface of a metal foil, wherein the insoluble rate with respect to N-methyl-2-pyrrolidone is 1% or more and 99% or less. Metal laminate.
(2) In a flexible metal laminate formed by laminating a heat resistant resin film layer obtained from an organic solvent-soluble condensed polymer on one surface of a metal foil, the heat resistant resin film layer is insoluble in N-methyl-2-pyrrolidone A flexible metal foil laminate having a rate of 1% or more after lamination.
(3) A heat-resistant resin film layer characterized by having an edge tear resistance (film thickness 20 μm) of 15 kg or more and a dimensional change rate of 0.1% or less when heated at 200 ° C. for 30 minutes is formed. (1) The flexible metal laminate according to any one of (1) to (2).
(4) The solder heat resistance is 350 ° C. or higher, the adhesive strength between the metal layer and the heat-resistant resin film layer is 80 g / mm or more, and the curl radius of curvature is 15 cm or more (1) to (3) The flexible metal laminated body in any one.
(5) The elastic modulus retention after immersion in a sodium hydroxide aqueous solution (40%) of the heat-resistant resin film layer at 25 ° C. for 100 hours is 40% or more, (1) to (4) The flexible metal laminated body in any one.
(6) The manufacturing method of the flexible metal laminated body in any one of (1) to (5) containing the following process (A), (B), and (C).
(A) A step of applying a heat-resistant resin solution to a metal foil and initially drying it so that the residual solvent ratio is 10 to 40% by weight.
(B) The process which winds up the said metal foil so that an application surface and a non-application surface may not contact, and uses it as a roll.
(C) A step of heat-treating the scroll.
(7) The method for producing a flexible metal laminate according to (6), wherein the initial drying is performed at a temperature lower by 70 ° C. to 130 ° C. than a boiling point of a solvent used for the heat resistant resin solution.
(8) The heat treatment is performed under a reduced pressure and / or in an inert gas atmosphere while removing the solvent so that the insoluble rate of the applied resin layer is 1% to 99% (6) The manufacturing method of the flexible metal laminated body in any one of 7).
(9) The method for producing a flexible metal laminate according to any one of (6) to (8), wherein in (C), the residue is dried under reduced pressure to have a residual solvent ratio of 5% by weight or less.
(10) At the time of winding, the coated surface is set to the outside, and a tape of a material different from the laminated material is sandwiched between uncoated portions of the resin solution on the coated surfaces at both ends of the laminated material, and / or at both ends of the laminated material The method for producing a flexible metal laminate according to any one of (6) to (9), wherein the front and back surfaces are wrapped with a tape.
(11) The method for producing a flexible metal laminate according to any one of (6) to (10), wherein the heat resistant resin is a polyimide soluble in an organic solvent and / or a polyamideimide.
(12) The flexible metal laminate according to any one of (6) to (11), wherein the heat resistant resin contains the following general formula (1) and / or the following general formula (2) as a structural unit: Body manufacturing method.
[0007]
[Chemical 3]

(In the formula, R 1 and R 2 may be the same or different and each represents hydrogen or an alkyl group having 1 to 4 carbon atoms.)
[0008]
[Formula 4]

(13) A flexible metal laminate produced by the method according to any one of (6) to (12).
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The heat-resistant resin used in the present invention may be basically any resin as long as it has a thermal expansion coefficient equivalent to that of a metal foil and is excellent in heat resistance, but preferably obtained by a polycondensation reaction. Aromatic polyimide and / or aromatic polyamideimide. The production of the aromatic polyimide or aromatic polyamideimide can be synthesized by a usual method, for example, an isocyanate method, an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, or the like.
[0010]
Examples of raw materials used for the aromatic polyimide include the following. Examples of the acid component include pyromellitic acid, benzophenone-3, 3 ', 4, 4'-tetracarboxylic acid, biphenyl-3, 3', 4, '-tetracarboxylic acid, diphenylsulfone 3, 3', 4, 4'- Tetracarboxylic acid, diphenyl ether-3,3 ', 4,4'-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, naphthalene-1 Monoanhydrides such as 4,5,8-tetracarboxylic acid, dianhydrides, esterified products and the like can be used alone or as a mixture of two or more. As the amine component, P-phenylenediamine, m-phenylenediamine, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 3,3'-diaminobenzanilide, 4,4'-diaminobenzanilide, 4,4'-diaminobenzophenone, 3, 3 ' -Diaminobenzophenone, 3,4'-diaminobenzophenone, 2,6-tolylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane, 4,4′-diaminodiphenyl Hexafluoropropane, 3,3′-diaminodiphenylhexafluoropropane, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylhexafluoroisopropylidene, P-xylenediamine, m -Xylenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, O-tolidine, 2,2'-bis (4-aminophenyl) propane, 2,2′-bis (4-aminophenyl) hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4- Aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl Propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (3 -Aminophenoxy) phenyl] hexafluoropropane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 2,2-bis [4- (4-amino Phenoxy) phenyl] hexafluoropropane, or diisocyanates corresponding to these, or a mixture of two or more thereof can be used. In addition, a resin separately polymerized by a combination of these acid component and amine component can be mixed and used.
[0011]
Raw materials used for aromatic polyamideimides include trimellitic anhydride, diphenyl ether-3, 3 ′, 4′-tricarboxylic acid anhydride, diphenylsulfone-3, 3 ′, 4′-tricarboxylic acid as acid components. Tricarboxylic acid anhydrides such as anhydride, benzophenone-3, 3 ', 4'-tricarboxylic acid anhydride, naphthalene, 1,2,4-tricarboxylic acid anhydride, alone or as a mixture, and the amine component is similar to polyimide A diamine or diisocyanate may be used alone or as a mixture. In addition, a resin separately polymerized by a combination of these acid component and amine component can be mixed and used.
[0012]
Particularly preferred heat-resistant resins in terms of heat resistance, chemical resistance, alkali resistance, coefficient of thermal expansion (dimensional change rate), formability in a scroll shape, and manufacturing cost are aromatic polyimides soluble in organic solvents, An aromatic polyamideimide, more preferably an aromatic polyamideimide containing a structural unit represented by the following general formula (1) or (2).
[Chemical formula 5]

(In the formula, R 1 and R 2 may be the same or different and each represents hydrogen or an alkyl group having 1 to 4 carbon atoms.)
[0013]
[Chemical 6]

[0014]
As a solvent for the heat-resistant resin solution used in the present invention, N-methyl-2-pyrrolidone, N, N′-dimethylformamide, N, N′-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethyl Urea, sulfolane, dimethylsulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone and the like, preferably N-methyl-2-pyrrolidone. Some of these can be replaced with hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone.
[0015]
The molecular weight of the heat-resistant resin used in the present invention is preferably in the range of 0.3 to 2.5 dl / g in N-methyl-2-pyrrolidone as a logarithmic viscosity at 30 ° C., more preferably 1.0. To 2.0 dl / g. When the logarithmic viscosity is 0.3 dl / g or less, the mechanical properties such as the bendability and the end tear resistance of the base material are insufficient, and when the logarithmic viscosity is 2.0 dl / g or more, the adhesive strength is insufficient, and the solution viscosity is low. Since it becomes high, the molding process becomes difficult.
[0016]
Moreover, in the range which does not impair heat resistance and a thermal expansion coefficient in the aromatic polyimide used by this invention, and aromatic polyamideimide, adipic acid, azelaic acid, sebacic acid, cyclohexane-4,4, '-dicarboxylic acid, Aliphatic and alicyclic dicarboxylic acids such as butane-1,2,4-tricarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid , Polycarboxylic acids, and their monoanhydrides, dianhydrides, esterified products, and the like, and as an amine component, tetramethylenediamine, hexamethylenediamine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, cyclohexane-1 Aliphatic and alicyclic diamines such as 1,4-diamine and diaminosiloxane or their corresponding diiso Aneto may be used alone or in combination of two or more. In addition, a resin separately polymerized by a combination of these acid component and amine component can be mixed and used.
[0017]
In the present invention, a heat resistant resin solution is applied to a metal foil and dried (hereinafter referred to as an initial drying step), and then wound, heat treated and dried in a roll shape (hereinafter referred to as a heat treatment / solvent removal step), and a flexible metal laminate is obtained. At the time of manufacturing, the amount of residual solvent after initial drying, that is, the amount of residual solvent when heat-treating / desolving in a roll shape is required to be at least 10% by weight, and as much as possible manufactures a flexible printed wiring board with less curl. can do. The residual solvent amount refers to the amount of solvent in the resin system including the solvent after coating and initial drying, and is represented by the mathematical formula [Equation 2] shown in the examples. When the residual solvent amount is less than 10% by weight, the internal stress accompanying the volumetric shrinkage of the solvent cannot be relaxed and the substrate cannot be curled under the processing conditions of the present invention.
[0018]
In addition, the larger the amount of the remaining solvent, the less the curl of the metal laminate. On the other hand, when the amount is too large, the applied resin layer flows out or adheres during winding. Depending on the type of resin, the upper limit of the residual solvent amount at the time of winding is 40% by weight, preferably 30% by weight.
[0019]
The initial drying needs to be performed at a temperature 70 to 130 ° C. lower than the boiling point of the solvent used for the heat resistant resin solution. When the drying temperature is higher than (the numerical value portion of the boiling point of the solvent in degrees Celsius -70) ° C., even if the residual solvent amount is 10% by weight or more, the unevenness of the residual solvent in the thickness direction of the resin layer increases. Since the amount of residual solvent in the resin surface layer is reduced, the subsequent relaxation in the form of a scroll is insufficient and curling occurs in the substrate. Further, when the temperature is lower than (the numerical value portion of the boiling point of the solvent expressed in Celsius -130) ° C., the drying time becomes longer and the productivity is lowered.
[0020]
The initial drying method can be performed by a conventionally known method such as a roll support method or a floating method. Moreover, it does not specifically limit as a coating method, A conventionally well-known method can be applied. After adjusting the viscosity of the coating solution with a roll coater, knife coater, doctor, blade coater, gravure coater, die coater, reverse coater, etc., it can be applied directly to the metal foil. Appropriate solution viscosity is in the range of 1 to 1000 poise in B-type viscosity at 25 ° C. Further, in coating, it is preferable to leave uncoated portions at both ends of the metal foil in order to improve the workability in the form of a scroll described later.
[0021]
In the present invention, the atmosphere during the heat treatment / desolvation must be performed under reduced pressure and / or in an inert gas atmosphere. When carried out in air, the resin layer is deteriorated or excessively cross-linked, and the curl of the substrate becomes large, or the mechanical properties of the resin layer are impaired. In addition, when heat treatment is performed in an air or oxygen atmosphere with a predetermined amount of a solvent such as N-methyl-2-pyrrolidone remaining, not only the mechanical properties of the resin layer but also the adhesion between the resin layer and the metal foil Sex is reduced. Preferably, it is necessary to heat-treat in an inert gas atmosphere after reducing the residual solvent ratio to 5% by weight or less under reduced pressure of about 2 mmHg or less. More preferably, the residual solvent ratio is reduced to 5% by weight or less under reduced pressure while maintaining the insoluble ratio of the applied resin layer at 20% or less, and then heat treatment is performed at a higher temperature in an inert gas atmosphere, thereby preventing heat resistance without curling. Can be obtained.
[0022]
The insoluble rate means that after heat treatment and solvent removal of the base material, only the resin layer excluding the metal foil is dissolved in a 0.5 wt% concentration solution in N-methyl-2-pyrrolidone at 100 ° C. for 2 hours. The insoluble content of the resin layer is shown by the formula [Equation 4] shown in the examples.
[0023]
The temperature and time conditions during the heat treatment / solvent removal are such that after the heat treatment / solvent removal step, the insoluble rate of the applied resin layer is 1% to 99%, preferably 5% to 85%. When the insolubility is 1% or less, heat resistance such as solder heat resistance and chemical resistance, particularly alkali resistance is insufficient, and when it is 99% or more, the curl of the substrate becomes large. Specifically, it is performed at a temperature of (numerical portion of glass transition point of heat resistant resin expressed in Celsius -250) ° C. to a temperature of (numerical portion of glass transition point of heat resistant resin expressed in Celsius +50) ° C.
[0024]
From the point of the present invention that the internal stress generated with the volumetric shrinkage of the solvent is completely removed while relaxing in the form of a scroll, a higher temperature, preferably a temperature higher than the glass transition point of the heat-resistant resin containing no solvent. If the temperature is too high, the stress can be effectively relieved, but conversely, if the temperature is too high, the resin undergoes a crosslinking reaction or deterioration reaction, so the internal strain increases and the substrate curl increases. . This temperature depends on the type of heat-resistant resin used, that is, long-term heat resistance, but in the present invention, it is necessary to set the temperature below (the numerical portion of the glass transition point of the heat-resistant resin expressed in Celsius +50) ° C. or lower. Also, if the heat treatment / solvent removal temperature is lower than (degree part of glass transition point of heat-resistant resin expressed in Celsius -250) ° C, it takes a long time for the cross-linking reaction to correct the curl of the substrate and increase the insolubility. , Productivity decreases.
[0025]
In the present invention, in order to remove the solvent completely by heat treatment with the solvent remaining, it is necessary to take up the resin solution coated surface and the non-coated surface so as not to contact each other. In order not to make contact, the tape is loosely wound, or the coated surface coated with the resin solution is placed outside, and a tape made of a material different from the laminate is sandwiched between the laminates. The position where the tape is sandwiched is not particularly limited, but it is preferably sandwiched between the portions of the coated surface where the resin solution is not coated (uncoated portions at both ends of the coated surface), or more preferably, FIG. Wrap the tape so that both sides of the laminate are wrapped with tape. The material of the tape may be selected from those which do not deform due to shrinkage, softening, melting, etc. at the heat treatment / desolvation temperature, but preferably tapes such as woven fabric and non-woven fabric made from cellulose, glass, carbon, aramid and the like. The thickness of the tape needs to be equal to or greater than the coating thickness of the resin solution. Below the coating thickness, particularly when the residual solvent amount is high, the coated surface and the non-coated surface come into contact with each other, and the productivity is lowered. The width of the tape is about 5 to 100 mm. If the thickness is 5 mm or less, the workability is deteriorated particularly when wrapping, and if it is 100 mm or more, the solvent removal efficiency is deteriorated or the area in contact with the coated portion is increased (or the uncoated width is increased). Yield is low due to poor appearance of the coated surface.
[0026]
As the metal foil used in the present invention, copper foil, aluminum foil, steel foil, nickel foil and the like can be used, and composite metal foil obtained by compounding these and metal foil treated with other metals such as zinc and chromium compounds. Can also be used. Although there is no limitation in particular about the thickness of metal foil, For example, metal foil of 3-50 micrometers can be used suitably.
[0027]
In the present invention, other resins, organic compounds, and inorganic compounds are mixed for the purpose of improving various characteristics of the flexible metal laminate, such as mechanical characteristics, electrical characteristics, slipperiness, and flame retardancy. Or you may make it react and use together. For example, lubricant (silica, talc, silicone, etc.), adhesion promoter, flame retardant (phosphorus, triazine, aluminum hydroxide, etc.), stabilizer (antioxidant, UV absorber, polymerization inhibitor, etc.), plating activity Agents, organic and inorganic fillers (talc, titanium oxide, fluoropolymer fine particles, pigments, dyes, calcium carbide, etc.), silicone compounds, fluorine compounds, isocyanate compounds, blocked isocyanate compounds, acrylic resins, urethane resins, Resins such as polyester resin, polyamide resin, epoxy resin, phenol resin and organic compounds, or these curing agents, inorganic compounds such as silicon oxide, titanium oxide, calcium carbonate, iron oxide, etc. are within the range not hindering the object of the present invention. Can be used together.
[0028]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not particularly limited by the examples. The evaluation method of the characteristic value in each example is as follows.
[0029]
Logarithmic viscosity Dissolved in N-methyl-2-pyrrolidone so that the polymer concentration becomes 0.5 g / dl, and the solution viscosity and solvent viscosity of the solution were measured at 30C with an Ubellose type viscosity tube. The following formula was used.
[0030]
[Expression 1]

[0031]
The glass transition point of the resin film layer obtained by etching away the metal foil of the flexible metal laminate of the present invention by the glass transition point TMA (thermal mechanical analysis / manufactured by Rigaku Corporation) tensile load method was measured under the following conditions. The film was measured for a film that was once heated to an inflection point in nitrogen at a heating rate of 10 ° C./min and then cooled to room temperature.
Load: 1g
Sample size: 4 (width) x 20 (length) mm
Temperature increase rate: 10 ° C./min Atmosphere: Nitrogen
Residual solvent ratio JIS K5400 was calculated from the following formula under drying conditions of 250 ° C. × 1 hour. (Regarding the residual solvent ratio of the metal laminate, after drying completely at 250 ° C. × 1 hr, the weight of the metal foil is obtained by removing the metal foil by an etching method, and the weight of the metal foil from the weight of the metal laminate before drying) The weight of [resin + solvent] was calculated, and the solvent weight was determined from the weight change before and after the absolute drying of the metal laminate, and was calculated from the mathematical formula [3].
[Expression 2]

[0033]
[Equation 3]

[0034]
Insoluble rate A 0.5 wt% N-methyl-2-pyrrolidone solution of the resin film layer obtained by etching and removing the metal foil of the molded flexible metal laminate was heat-treated at 100C for 2 hours to remove the insoluble matter. The following formula was used for calculation.
[Expression 4]

[0035]
Substrate curl The radius of curvature of the curl of the flexible metal laminate was determined (sample size; 10 cm x 10 cm).
[0036]
Solder heat resistance After a metal foil of a flexible metal laminate is etched by a subtractive method to create a circuit pattern with a width of 1 mm, the sample is conditioned at 40 ° C. and 85% (humidity) for 5 hours and then flux-washed. Soldering was performed at 350 ° C., and the presence or absence of peeling or swelling was observed with a microscope.
[0037]
Measurement was performed in the MD direction and the TD direction under conditions of 150 ° C. × 30 minutes, 200 ° C. × 30 minutes, and 250 ° C. × 30 minutes with a dimensional change rate IPC-FC241.
[0038]
A sample in which a circuit pattern having a width of 1 mm was prepared by the subtractive method with the adhesive strength IPC-FC241 was measured at a pulling speed of 50 mm / min and a peeling angle of 90 °.
[0039]
End tear resistance A sample having a width of 20 mm and a length of 200 mm was prepared from a resin film obtained by etching away a metal foil, and measured according to JIS-C2318.
[0040]
Strength, elongation, and elastic modulus of resin film A sample having a width of 10 mm and a length of 100 mm was prepared from a resin film from which a metal foil was removed by etching, and measured with a Tensilon tensile tester under the following conditions.
Sample humidity control: 40 ° C., 85% (humidity) × 5 hours Tensile speed: 20 mm / min Distance between chucks: 40 mm
[0041]
Alkaline resistance test of resin film A heat resistant resin film obtained by etching and removing a metal foil in a 40% by weight sodium hydroxide aqueous solution was immersed for 100 hours, and after the immersion, the elastic modulus of a sufficiently washed sample was measured under the above conditions. did. Next, the retention rate was determined from the elastic modulus before and after immersion.
[Equation 5]

[0042]
The bending resistance <br/> metal foil heat-resistant resin film having a width of 10mm, which was removed by etching JIS C 5016, the load 500 g, measured at the bending diameter 0.38 mm, were determined bending number until the film breaks.
[0043]
Synthesis example 1 Synthesis of Resin A 192 g of trimellitic anhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.), 3,3′-dimethyl-4,4′-biphenyl diisocyanate (manufactured by Nippon Soda Co., Ltd., O-trizine dii) Isocyanate) 211 g (80 mol%), 2,4-tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate T-100) 35 g (20 mol%), sodium methylate (manufactured by Wako Co., Ltd.) 0.5 g, and N -2.5 kg of methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) was added, the temperature was raised to 150 ° C. for 1 hour, and further reacted at 150 ° C. for 5 hours. The resulting polymer had a logarithmic viscosity of 1.6 and a glass transition point of 320 ° C.
[0044]
Synthesis example 2 Synthesis of Resin B In a reaction vessel, 192 g of trimellitic anhydride, 1,5-naphthalene diisocyanate (manufactured by Sumitomo Bayer Urethane Co., Ltd., Desmodur 15) 157 g (75 mol%), 4,4′-diphenylmethane diisocyanate ( Sumitomo Bayer Urethane Co., Ltd.) 63 g (25 mol%), diazabicycloundecene (San Apro Co., Ltd.) 1 g, and N-methyl-2-pyrrolidone 2 kg are added, heated to 170 ° C. at 1 hr, and further The reaction was carried out at 170 ° C. for 5 hours. The obtained polymer had a logarithmic viscosity of 1.4 and a glass transition point of 356 ° C.
[0045]
Synthesis example 3 Synthesis of resin B-1 In a reaction vessel, 384 g of trimellitic anhydride, 378 g of 1,5-naphthalene diisocyanate (90 mol%), 50 g (10 mol%) of 4,4′-diphenylmethane diisocyanate, potassium fluoride ( (Manufactured by Tokyo Chemical Industry Co., Ltd.) 2.5 g and 2 kg of N-methyl-2-pyrrolidone were added, the temperature was raised to 130 ° C. over 1 hr, and further reacted at 130 ° C. for 5 hr. The resulting polymer had a logarithmic viscosity of 1.7 and a glass transition point of 381 ° C.
Synthesis example 4 Synthesis of resin B-2 In a reaction vessel, 384 g of trimellitic anhydride, 399 g of 1,5-naphthalene diisocyanate (95 mol%), 25 g (5 mol%) of 4,4′-diphenylmethane diisocyanate, potassium fluoride 2 0.5 g and 2 kg of N-methyl-2-pyrrolidone were added, the temperature was raised to 100 ° C. over 1 hr, and the mixture was further reacted at 100 ° C. for 5 hr. The resulting polymer had a logarithmic viscosity of 1.8 and a glass transition point of 390 ° C.
Synthesis example 5 Synthesis of resin B-3 In a reaction vessel, 384 g of trimellitic anhydride, 210 g of 1,5-naphthalene diisocyanate (50 mol%), 251 g of 4,4′-diphenylmethane diisocyanate (50 mol%), potassium fluoride 2 0.5 g and 1.5 kg of N-methyl-2-pyrrolidone were added, the temperature was raised to 150 ° C. over 1 hr, and the reaction was further continued at 150 ° C. for 5 hr. The obtained polymer had a logarithmic viscosity of 1.2 and a glass transition point of 367 ° C.
Synthesis Example 6 Synthesis of Resin A-1 192 g of trimellitic anhydride, 251 g (95 mol%) of 3,3′-dimethyl-4,4′-biphenyl diisocyanate, 8.7 g of 2,4-tolylene diisocyanate in a reaction vessel. (5 mol%), 0.5 g of sodium methylate, and 2.5 kg of N-methyl-2-pyrrolidone were added, the temperature was raised to 150 ° C. at 1 hr, and the mixture was further reacted at 150 ° C. for 5 hr. The resulting polymer had a logarithmic viscosity of 1.7 and a glass transition point of 315 ° C.
[0049]
Examples and comparative examples
Using a comma coater on the treated surface of the 18 μm-rolled copper foil, the resin solution obtained in the synthesis example is continuously left so that both ends are left at about 1 cm (without coating) and the thickness after solvent removal is 20 μm. Coated. Next, the line speed was set in a 20 m long flotation-type drying furnace so that the drying conditions shown in Table 1 were satisfied. The residual solvent ratio of the obtained metal laminate was the value shown in Table-1.
In Examples 1 to 8 and the comparative example, the glass laminate tape having a width of 1 cm and a thickness of 200 μm was sandwiched between the long laminates obtained in this manner and a diameter of 3 inches. It was wound up on an aluminum tube. In Examples 9 to 11, a glass cloth tape having a width of 1 cm and a thickness of 300 μm was sandwiched between the non-coated surfaces at both ends of the long laminate, and wound around an aluminum tube having a diameter of 3 inches. Further, in Example 12, the tape was wrapped as shown in FIG. 1 and wound around an aluminum tube having a diameter of 3 inches so that the coated surface was on the outside.
Subsequently, the wound roll was put into a vacuum dryer or an inert oven, and was heat-treated under the heat treatment and solvent removal conditions shown in Table-1. The solvent in the coating film of the obtained flexible metal laminate was completely removed, and the characteristics were as shown in Table-2 and Table-3.
[0050]
[Table 1]

[0051]
[Table 2]

[0052]
[Table 3]

[0053]
【The invention's effect】
As described above, the flexible metal laminate of the present invention is excellent in curling and dimensional change because it is heat-treated while applying a heat-resistant resin solution to a metal foil and drying it, and then winding it once and further removing the solvent. It is industrially useful because of its excellent heat resistance and chemical resistance (especially alkali resistance).
[Brief description of the drawings]
FIG. 1 is a schematic view of a wound state of a metal foil laminate according to the present invention.

Claims (6)

It is obtained from a condensed polymer characterized by having an insolubility rate of 1% or more with respect to N-methyl-2-pyrrolidone on one side of a metal foil, including the following steps (A), (B), and (C): The manufacturing method of the flexible metal laminated body in which a heat resistant resin film layer is formed .
(A) A heat resistant resin solution is applied to a metal foil and initially dried, and the initial drying is performed at a temperature 70 to 130 ° C. lower than the boiling point of the solvent used for the heat resistant resin solution, and the residual solvent ratio is 10 to 40 wt. % Process.
(B) The process which winds up the said metal foil so that an application surface and a non-application surface may not contact, and uses it as a roll.
(C) A step of heat-treating the scroll. 2. The flexible metal according to claim 1 , wherein the heat treatment is performed under a reduced pressure and / or in an inert gas atmosphere while removing the solvent so that the insoluble rate of the applied resin layer becomes 1% to 99%. A manufacturing method of a layered product. In (C), and dried under reduced pressure, the manufacturing method of the flexible metal laminate according to claim 1 or 2, characterized in that the residual solvent ratio of 5 wt% or less. At the time of winding, the coated surface is outside, the tape of the material different from the laminated material is sandwiched between the uncoated portions of the resin solution on the coated surface at both ends of the laminated material, and / or the front and back of the laminated material at both ends are taped method for producing a flexible metal laminate according to any one of claims 1及至3, characterized in that enveloping at. The method for producing a flexible metal laminate according to any one of claims 1 to 4 , wherein the heat-resistant resin is polyimide and / or polyamideimide soluble in an organic solvent. The said heat resistant resin contains the following general formula (1) and / or the following general formula (2) as a structural unit, The manufacturing method of the flexible metal laminated body in any one of Claim 1 to 5 characterized by the above-mentioned.

(In the formula, R 1 and R 2 may be the same or different and each represents hydrogen or an alkyl group having 1 to 4 carbon atoms.)

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