JP4180292B2 - Film adhesive and laminated member in which the adhesive is laminated - Google Patents

Description

（式中、Ｒ¹は水素原子、またはメチル基を示し、Ｒ²は独立して、炭素数４以下の有機基、ハロゲン基、ニトリル基を示し、ｎは０または１〜５の整数を示す）。
【００１０】
本発明のスチレン誘導体は、モノマー状態、オリゴマー状態のどちらでも良いが、オリゴマー状態で添加する場合、２０量体以下、好ましくは１０量体以下が好ましい。具体例としては、スチレン、スチレンオリゴマー（４〜６量体混合物）、α−メチルスチレン、クロロスチレン、ジクロロスチレン、トリクロロスチレン、ブロモスチレン、メトキシスチレンなどが挙げられる。オリゴマーの分子量が高すぎると、他成分との相溶性が低下する可能性があり好ましくなく、モノマー状態、特にスチレンモノマーが入手性、熱特性等により好ましい。添加割合としては、熱可塑性ポリイミド１００重量部に対して、０．１〜５０重量部、好ましくは５〜２０重量部加えるのが望ましい。少なすぎると低温での仮圧着性を十分に発現せず、多すぎると耐熱性に劣るものとなる。添加の際には、他成分との相溶性を向上させるため、有機溶媒で希釈した状態で添加するのが好ましい。有機溶媒の種類は特に限定しないが、他成分の溶媒と同一のものを用いた方が好ましい。
【００１１】
本発明のように熱可塑性を有するスチレン誘導体もしくはオリゴマーを用いることにより、熱可塑性ポリイミドの大幅なＴｇ低下、及びエポキシ樹脂割合の大幅な増加を行うことなく、従来の熱可塑性ポリイミド、エポキシ樹脂ブレンド型接着剤よりも更に低温での仮圧着を発現させることが可能となった。すなわち、スチレン誘導体もしくはオリゴマーを導入することにより、接着剤の見かけ上のガラス転移温度（Ｔｇ）を下げることができ、低温、低圧での仮圧着性を発現する。また、エポキシ部数を極端に増やす必要が無いため、単層シート状態での柔軟性を保つことができ、本圧着時には高い接着性を示す。そのため、耐熱性、柔軟性と仮圧着性のバランスに優れたフィルム状接着剤が得られる。
【００１２】
本発明のフィルム状接着剤に用いる熱可塑性ポリイミドは、低温、低圧での仮圧着性を発現するために、Ｔｇが２００℃以下であることが望ましい。Ｔｇが２００℃よりも高い場合、より高い加工温度、圧力が必要となる。それを補うためにエポキシ樹脂もしくはスチレン誘導体の割合を増やすと、耐熱性と加工性の両立を取ることが困難となる。
【００１３】
さらに、本発明のフィルム状接着剤に用いる熱可塑性ポリイミドは、環状エーテル系溶媒に固形分濃度１０％以上の溶解性を示すことが望ましい。環状エーテル系溶媒を使用することで、接着剤溶液塗布後、比較的低温で溶媒を除去できる。Ｎ，Ｎ−ジメチルホルムアミドやＮ−メチル−２−ピロリドン等の高沸点溶媒のみを用いた場合、エポキシ樹脂のＢステージ状態と残留溶媒のバランスを取ることが困難であった。しかし、環状エーテル系溶媒を使用することにより、フィルム中からの溶媒除去が容易になり、残溶媒を著しく低減させる乾燥条件を適用しても、各物性を発現させることが可能となった。
【００１４】
この熱可塑性ポリイミドは、下記一般式（２）で表されるエステル酸二無水物ならびに下記一般式（３）で表されるジアミン化合物のうち少なくとも１種を用いる。
【００１５】
【化５】

（式中、Ｘは−（ＣＨ₂）_j−、もしくは芳香環を含む二価の有機基を示す。ｊは１以上１０以下の整数である。）
【００１６】
【化６】

（式中、Ｙは独立して、−Ｃ（＝Ｏ）−、−ＳＯ₂−、−Ｏ−、−Ｓ−、−（ＣＨ₂）_k−、−ＮＨＣＯ−、−Ｃ（ＣＨ₃）₂−、−Ｃ（ＣＦ₃）₂−、−Ｃ（＝Ｏ）Ｏ−、または単結合を示す。ｋ及びｍは１以上５以下の整数である。）。
【００１７】
一般式（３）で表されるジアミンと類似した構造を持つものとして、アミノ基がメタ位以外のオルト位、パラ位に結合しているものも存在しうるが、一般式（３）で表されるメタ位についているのが好ましい。メタ位にアミノ基があることにより、生成されるポリイミドの有機溶媒への溶解性がより良好となり、加工性に優れた接着剤溶液が得られる。一般式（３）で表されるジアミンは、１種または２種以上混合して用いうる。
【００１８】
これらの酸二無水物、及びジアミンは、それぞれ各成分の５０モル％以上用いることが好ましく、８０モル％以上用いるのがさらに好ましく、１００モル％用いるのが特に好ましい。５０モル％よりも少ないと、有機溶媒に対する溶解性を十分に発現しなくなる。
【００１９】
一般式（２）で表されるエステル酸二無水物の具体例としては、２，２−ビス（４−ヒドロキシフェニル）プロパンジベンゾエート−３，３’，４，４’−テトラカルボン酸二無水物、ｐ−フェニレンビス（トリメリット酸モノエステル無水物）、３，３’，４，４’−エチレングリコールベンゾエートテトラカルボン酸二無水物、４，４’−ビフェニレンビス（トリメリット酸モノエステル無水物）、１，４−ナフタレンビス（トリメリット酸モノエステル無水物）、１，２−エチレンビス（トリメリット酸モノエステル無水物）、１，３−トリメチレンビス（トリメリット酸モノエステル無水物）、１，４−テトラメチレンビス（トリメリット酸モノエステル無水物）、１，５−ペンタメチレンビス（トリメリット酸モノエステル無水物）、１，６−ヘキサメチレンビス（トリメリット酸モノエステル無水物）等が挙げられるが、下記一般式（４）：
【００２０】
【化７】

で表される２，２−ビス（４−ヒドロキシフェニル）プロパンジベンゾエート−３，３’，４，４’−テトラカルボン酸二無水物、もしくは下記一般式（５）：
【００２１】
【化８】

で表される３，３’，４，４’−エチレングリコールベンゾエートテトラカルボン酸二無水物が特に好ましい。
【００２２】
本発明にかかるフィルム状接着剤に用いる熱可塑性ポリイミド樹脂は、その前駆体であるポリアミド酸重合体を脱水閉環して得られる。このポリアミド酸溶液は、アルゴン、窒素などの不活性雰囲気中において、前記一般式（２）で表されるエステル酸二無水物及び前記一般式（３）で表される１種以上のジアミンをそれぞれ各成分の５０モル％以上用い、全酸二無水物と全ジアミンとが実質的に等モルになるように使用し、有機極性溶媒中で重合して得られる。
【００２３】
各モノマーの添加順序は特に限定されず、酸二無水物成分を有機極性溶媒中に先に加えておき、ジアミン成分を添加し、ポリアミド酸重合体の溶液としても良いし、ジアミン成分を有機極性溶媒中に先に適量加えて、次に酸二無水物を加え、最後に残りのジアミン成分を加えて、ポリアミド酸重合体の溶液としても良い。この他にも、当業者に公知の様々な添加方法がある。
【００２４】
上記で得られたポリアミド酸重合体を、熱的または化学的方法により、脱水閉環し、ポリイミド樹脂を得る。イミド化の方法としては、ポリアミド酸溶液を加熱処理して脱水する熱的方法、脱水剤を用いて脱水する化学的方法が挙げられる。
【００２５】
化学的方法による脱水剤としては、例えば、無水酢酸等の脂肪族酸無水物、及び芳香族酸無水物が挙げられる。また、触媒としては、トリエチルアミン等の脂肪族第３級アミン類、ジメチルアニリン等の芳香族第３級アミン類、ピリジン、イソキノリン等の複素環第３級アミン類等が挙げられる。
【００２６】
上記のようにして得られた熱可塑性ポリイミドはそのまま溶液として用いることができる。あるいはポリアミド酸の重合に用いた、溶媒を良く溶かすが、ポリイミドが溶解しにくい貧溶媒中に、ポリイミド溶液を投入して、ポリイミド樹脂を析出させて未反応モノマーを取り除いて精製し、乾燥させ固形のポリイミド樹脂としてから、適宜、本発明の接着剤溶液に用いることもできる。
【００２７】
熱的方法としては、例えば、ポリアミド酸を重合した後に真空オーブン中に投入し、減圧下で加熱することによってイミド化を行い、固形のポリイミド樹脂として取り出す手法が挙げられる。
【００２８】
本発明のフィルム状接着剤は、成分中にエポキシ樹脂を含んでいるため、ポリイミドの有する優れた耐熱性に、さらに良好な低温加工性が付与されている。使用されるエポキシ樹脂の例としては、エピコート８２８（油化シェル社製）等のビスフェノールＡ型樹脂、１８０Ｓ６５（油化シェル社製）等のオルソクレゾールノボラック樹脂、１５７Ｓ７０（油化シェル社製）等のビスフェノールＡノボラック樹脂、１０３２Ｈ６０（油化シェル社製）等のトリスヒドロキシフェニルメタンノボラック樹脂、ＥＳＮ３７５等のナフタレンアラルキルノボラック樹脂、テトラフェニロールエタン１０３１Ｓ（油化シェル社製）、ＹＧＤ４１４Ｓ（東都化成）、トリスヒドロキシフェニルメタンＥＰＰＮ５０２Ｈ（日本化薬）、特殊ビスフェノールＶＧ３１０１Ｌ（三井化学）、特殊ナフトールＮＣ７０００（日本化薬）、ＴＥＴＲＡＤ−Ｘ，ＴＥＴＲＡＤ−Ｃ（三菱瓦斯化学社製）等のグリシジルアミン型樹脂などが挙げられる。
【００２９】
エポキシ樹脂の混合割合は、前記熱可塑性ポリイミド樹脂１００重量部に対して、１０〜１００重量部、好ましくは２０〜７０重量部加えるのが望ましい。少なすぎると仮圧着性を十分に発現せず、多すぎると可撓性、耐熱性に劣るものとなる。
【００３０】
該接着剤には、エポキシ硬化剤、または硬化促進剤を添加することが好ましい。エポキシ硬化剤としては、例えば３，３−ジアミノジフェニルスルフォン、４，４−ジアミノフェニルスルフォン等を含む市販のものを使用することができ、特に限定されない。硬化促進剤としては、イミダゾール系化合物、例えば２−アルキルイミダゾール、２−アルキル−４−メチルイミダゾール、２−アルキル−４−エチルイミダゾール、１−（２−シアノエチル）−２−アルキルイミダゾール、２−フェニルイミダゾール、２，４−ジフェニルイミダゾール、２−フェニル−４−メチルイミダゾール等がある（アルキル基の炭素数は１から４が好ましい）。他の硬化促進剤としては、酸無水物、例えば無水フタル酸、無水テトラヒドロフタル酸、無水ヘキサヒドロフタル酸、無水トリメリット酸等がある。さらに他の硬化促進剤としては、アミン系物質、例えばジエチレントリアミン、トリエチレンテトラミン、メタキシレンジアミン、ジアミンフェニルメタン等が挙げられる。これらは単独、もしくは２種以上混合して用いることが出来る。さらに吸水性、耐熱性、接着性等の向上のために、種々のカップリング剤を添加することもできる。
【００３１】
本発明のフィルム状接着剤は、有機溶媒に前記熱可塑性ポリイミド樹脂、スチレン誘導体もしくはオリゴマー、エポキシ樹脂、及びその硬化剤を溶解させた接着剤溶液を、ポリエチレンテレフタレート（ＰＥＴ）フィルム等、支持体となる高分子フィルム上に塗布乾燥させた後に剥離することによって得られる。
【００３２】
また、本発明の接着性積層部材は、該接着剤溶液をポリイミドからなる絶縁フィルムの少なくとも片面に流延または塗布し、その後乾燥して得られる。また本発明のフィルム状接着剤はポリイミド系接着剤の単層フィルムであるので、これをポリイミドフィルムとラミネートして同様の構成の接着性積層部材として用いることも可能である。
【００３３】
接着剤を構成する各成分を溶解させる有機溶媒としては、乾燥工程の温度を低くできるため熱硬化性樹脂の硬化が進みすぎないという点、ならびに溶媒残留による物性低下を抑えられるという点から、低沸点の環状エーテル系溶媒を主成分とすることが好ましい。環状エーテル系溶媒としては、テトラヒドロフラン（ＴＨＦ）、１，４−ジオキサン、ジオキソラン等が挙げられる。これらのエーテル系溶媒を単独もしくは混合し、あるいは有機極性溶媒と組み合わせて用いる。例えば、ジメチルスルホキシド、ジエチルスルホキシド等のスルホキシド系溶媒、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド等のホルムアミド系溶媒、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド等のアセトアミド系溶媒が挙げられる。組み合わせる溶媒の種類、数、混合する順番は特に限定しないが、全溶媒量に対して、上記エーテル系溶媒を好ましくは３０重量％以上、更に好ましくは６０重量％以上含んでいることが好ましい。これらの溶媒に上記成分を溶解させることにより、接着剤溶液を得る。この時、熱可塑性ポリイミドを溶媒に溶解させた後、残りの成分を添加し、接着剤溶液として用いても良いし、各成分をそれぞれ溶媒に溶解させた後、それらの溶液を混合して用いても良い。熱可塑性ポリイミド樹脂を溶解させる際に溶解しにくいようであれば、必要に応じて加熱を行う。ただし、環状エーテル系溶媒は沸点が低く揮発しやすいため、加熱温度、加熱時間は必要最低限に留める。また、熱硬化性樹脂を溶解させる際は、できるだけ加熱を控えた方が好ましい。
【００３４】
接着層の塗布法としては、アプリケーター、バーコーター、スピンコーター、グラビアコーター等が挙げられるが、特に限定しない。いずれの手法を取るにしても、接着層の厚みとしては、３〜６０μｍ程度が好ましい。接着剤塗布後の乾燥工程については、特に手法を限定しないが、ある程度の厚みを有する場合、発泡を防ぐために、低い温度から段階的に昇温しながら乾燥を行うことが好ましい。また、乾燥時間にもよるが、エポキシ成分の硬化が進みすぎるのを防ぐため、乾燥温度は２００℃以下に留めるのが好ましい。
【００３５】
本発明の積層部材は、必要に応じて離型フィルムを少なくとも片面に配する。使用する離型フィルムとしては、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリフェニレンスルフィド（ＰＰＳ）が挙げられる。離型フィルムの厚みは使用状況に応じて選択するため、ここでは限定しないが、加工工程時の剥離を容易にするために、接着層に接する面には剥離処理が施されていることが好ましい。処理法としては、シリコン処理、アルキッド処理、フッ素処理、ポリオレフィン処理などが挙げられるが、特に限定しない。フィルム状接着性積層部材の接着層に対する離型フィルムの接着強度は、１〜５０ｇｆ／ｃｍの範囲にあることが望ましく、さらに望ましくは５〜２０ｇｆ／ｃｍである。接着強度が低すぎると使用前に剥離する可能性が生じ、接着強度が高すぎるとスムーズな剥離が困難になる。離型フィルムのラミネート法については特に限定しないが、シワ及び気泡が入るのを防ぐために、ある程度の圧力をかけながら貼り合わせることが望ましい。また、離型フィルムが必要以上に接着してしまうのを避けるため、ラミネート温度は１４０℃以下に留めるのが望ましい。
【００３６】
上記のようにして得られる本発明のフィルム状接着剤及び積層部材は、多層ＦＰＣのような積層材料等に好適に用いられる特性を有する。具体的には、耐熱性を損なうことなく、温度１２０℃以下、圧力５ｋｇｆ／ｃｍ²以下、線速０．５ｍ／ｍｉｎ以下という低温、低圧での条件で、仮圧着が可能であり、１０ｇｆ／ｃｍ以上、１００ｇｆ／ｃｍ以下の強度を示し、さらに仮圧着後に引き剥がしても、再度仮圧着が可能である。繰り返し使用するためには、仮圧着強度が上記、１０ｇｆ／ｃｍ以上、１００ｇｆ／ｃｍ以下であることが好ましく、１０ｇｆ／ｃｍ以下であると、位置ずれ等を起こし仮圧着したことにならず、また１００ｇｆ／ｃｍ以上であると、引き剥がしが困難になり、不具合が起こる。
【００３７】
本発明にかかるフィルム状接着剤及び積層部材は、仮圧着だけでなく、銅箔等の金属箔やポリイミドフィルムと本圧着する際にも比較的低温での接着が可能であり、使用に際し加工性に優れる。この場合の接着条件としては、接着硬化するために必要十分である接着条件で有れば良く、具体的には加熱温度１５０〜２５０℃、圧力１〜１００ｋｇｆ／ｃｍ²で加熱時間５〜２０分程度の条件で加熱加圧する事が好ましい。また、エポキシ成分の硬化反応を十分に進行させるため、必要に応じてアフターキュアを行ってもかまわない。アフターキュアの条件としては、温度１５０〜２５０℃、１〜３時間程度の条件が好ましいが、特に限定されるものではない。
【００３８】
【実施例】
以下、実施例により本発明を具体的に説明する。本発明はこれら実施例のみに限定されるものではない。
【００３９】
実施例及び比較例における仮圧着温度の決定、及び最終引き剥し強度の評価法は次のとおりである。
【００４０】
（仮圧着温度の決定）
以下の手順でフィルム状接着剤もしくは積層部材と、それらの硬化物との仮圧着温度を評価した。
１）実施例及び比較例で得られたフィルム状接着剤ならびに積層部材を２００℃で１時間乾燥し、接着剤を硬化させ硬化部材とする。
２）各フィルム状接着剤、積層部材の片面に上記硬化部材を重ね、熱ラミネート装置にて貼り合わせる。ラミネート装置は、本ラミネートロール、徐冷ラミネートロールをそれぞれ１対ずつ有する熱ラミネート装置（ロール材質：シリコンゴム）を用いた。
【００４１】
温度：９０〜１５０℃まで１０℃刻みでラミネート
圧力：３ｋｇｆ／ｃｍ²
速度：０．３ｍ／ｍｉｎ
３）硬化部材との引き剥がし強度を測定。
４）１０ｇｆ／ｃｍ以上の接着強度を発現する最も低いラミネート温度を、仮圧着温度とする。引き剥がし強度は、ＪＩＳ Ｃ６４８１に従って測定した。但し、導体ではなく各フィルム状接着剤、積層部材を１ｃｍ幅で引き剥がして測定した。
【００４２】
（最終引き剥がし強度）
以下の手順で銅箔を接着したときの引剥強度の測定を行った。各フィルム状接着剤もしくは積層部材と１８μｍの圧延銅箔とを重ね合わせ、温度２００℃、圧力３０ｋｇｆ／ｃｍ²で５分間加熱加圧し、銅張フレキシブル積層板を得た。得られた銅張りフレキシブル積層板の引剥強度を、ＪＩＳ Ｃ６４８１に従って測定した。但し、導体幅は３ｍｍで測定した。
【００４３】
（合成例１）容量１０００ｍｌのガラス製フラスコにＮ，Ｎ−ジメチルホルムアミド（以下、ＤＭＦという）を３２７ｇ、１，３−ビス（３−アミノフェノキシ）ベンゼン（以下、ＡＰＢという）を０．２０ｍｏｌ加え、窒素雰囲気下で攪拌しながら、２，２−ビス（４−ヒドロキシフェニル）プロパンジベンゾエート−３，３’，４，４’−テトラカルボン酸二無水物（以下、ＥＳＤＡという）を０．２０ｍｏｌ徐々に添加した。氷浴下で３０分間攪拌し、粘度が１５００ｐｏｉｓｅに達したところで攪拌をやめ、ポリアミド酸溶液を得た。
【００４４】
このポリアミド酸溶液３００ｇを、テフロン（登録商標）コートしたバットに移し、真空オーブンで２００℃×３時間、５ｍｍＨｇ（約０．００７気圧）の圧力で減圧加熱した。真空オーブンより取り出し、８５ｇの熱可塑性ポリイミドを得た。
【００４５】
（合成例２）容量１０００ｍｌのガラス製フラスコにＤＭＦを３８８ｇ、３，３’−ビス（アミノフェノキシフェニル）スルフォン（以下、ＢＡＰＳ−Ｍという）を０．１９ｍｏｌ、３，３’−ジヒドロキシ−４，４’−ジアミノビフェニル（以下、ＨＡＢという）を０．０１ｍｏｌ加え、窒素雰囲気下で攪拌しながら、３，３’，４，４’−エチレングリコールベンゾエートテトラカルボン酸二無水物（以下、ＴＭＥＧという）を０．２０ｍｏｌ徐々に添加した。氷浴下で３０分間攪拌し、粘度が１５００ｐｏｉｓｅに達したところで攪拌をやめ、ポリアミド酸溶液を得た。
【００４６】
このポリアミド酸溶液３００ｇを、テフロン（登録商標）コートしたバットに移し、真空オーブンで２００℃×３時間、５ｍｍＨｇ（約０．００７気圧）の圧力で減圧加熱した。真空オーブンより取り出し、８５ｇの熱可塑性ポリイミドを得た。
【００４７】
（合成例３）容量１０００ｍｌのガラス製フラスコにＤＭＦを３２６ｇ、ＡＰＢを０．１９ｍｏｌ、ＨＡＢを０．０１ｍｏｌを加え、窒素雰囲気下で攪拌しながら、ＴＭＥＧを０．２０ｍｏｌ徐々に添加した。氷浴下で３０分間攪拌し、粘度が１５００ｐｏｉｓｅに達したところで攪拌をやめ、ポリアミド酸溶液を得た。
【００４８】
このポリアミド酸溶液３００ｇを、テフロン（登録商標）コートしたバットに移し、真空オーブンで１８０℃×３時間、５ｍｍＨｇ（約０．００７気圧）の圧力で減圧加熱した。真空オーブンより取り出し、８４ｇの熱可塑性ポリイミドを得た。
【００４９】
（実施例１）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにエピコート１０３２Ｈ６０（油化シェル社製）のジオキソラン溶液（ＳＣ＝３０％）を３０ｇ、スチレンモノマーのジオキソラン溶液（ＳＣ３０％）を１０ｇ、４，４’−ジアミノジフェニルスルフォン（以下、４，４’−ＤＤＳという）のジオキソラン溶液（ＳＣ＝２０％）を１３．５ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００５０】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００５１】
（実施例２）合成例２で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス８５ｇにＮＣ−３０００（日本化薬製）のジオキソラン溶液（ＳＣ＝３０％）を２５ｇ、スチレンモノマーのジオキソラン溶液（ＳＣ＝３０％）を５ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を１１．３ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００５２】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００５３】
（実施例３）合成例３で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにエピコート１０３２Ｈ６０（油化シェル社製）のジオキソラン溶液（ＳＣ＝３０％）を３０ｇ、スチレンモノマーのジオキソラン溶液（ＳＣ＝３０％）を１０ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を１３．５ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００５４】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００５５】
（実施例４）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにＴＥＴＲＡＤ−Ｃ（三菱瓦斯化学社製）のジオキソラン溶液（ＳＣ＝３０％）を３０ｇ、スチレンの４〜６量体の混合物であるオリゴマーのジオキソラン溶液（ＳＣ＝３０％）を５ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を１３．５ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００５６】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００５７】
（実施例５）実施例１と同様にして得られた接着剤溶液を１２．５μｍ厚のポリイミドフィルム（アピカル１２．５ＮＰＩ、鐘淵化学工業社製）上に流延し、６０℃で２分間乾燥した。反対面にも同様に流延し、６０℃で２分間乾燥した。更に、このフィルムを金枠に固定して１５０℃で５分間乾燥し、総厚２２．５μｍのフィルム状積層部材を得た。
【００５８】
（実施例６）実施例２と同様にして得られた接着剤溶液を１２．５μｍ厚のポリイミドフィルム（アピカル１２．５ＮＰＩ、鐘淵化学工業社製）上に流延し、６０℃で２分間乾燥した。反対面にも同様に流延し、６０℃で２分間乾燥した。更に、このフィルムを金枠に固定して１５０℃で５分間乾燥し、総厚２２．５μｍのフィルム状積層部材を得た。
【００５９】
（比較例１）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにエピコート１０３２Ｈ６０（油化シェル社製）のジオキソラン溶液（ＳＣ＝３０％）を３０ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を１３．５ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００６０】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００６１】
（比較例２）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス４０ｇにエピコート１０３２Ｈ６０（油化シェル社製）のジオキソラン溶液（ＳＣ＝３０％）を６０ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を２７ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００６２】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での硬化処理後は脆く、柔軟性が不十分であった。
【００６３】
（比較例３）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにエピコート１０３２Ｈ６０（油化シェル社製）のジオキソラン溶液（ＳＣ＝３０％）を３０ｇ、４，４’−ＤＤＳのジオキソラン溶液（ＳＣ＝２０％）を１３．５ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００６４】
上記で得た接着剤溶液を１２．５μｍ厚のポリイミドフィルム（アピカル１２．５ＮＰＩ、鐘淵化学工業社製）上に流延し、６０℃で２分間乾燥した。反対面にも同様に流延し、６０℃で２分間乾燥した。更に、このフィルムを金枠に固定して１５０℃で５分間乾燥し、総厚２２．５μｍのフィルム状積層部材を得た。
【００６５】
（比較例４）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニス７０ｇにスチレンモノマーのジオキソラン溶液（ＳＣ＝３０％）を１０ｇ添加し、撹拌を行って均一に混合させ、接着剤溶液を得た。
【００６６】
上記で得た接着剤溶液を２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での加熱処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００６７】
（比較例５）合成例１で得たポリイミド粉末３０ｇを、７０ｇのジオキソランに添加し、撹拌を行って溶解させ、ワニスを得た（ＳＣ＝３０％）。このワニスを２５μｍ厚のＰＥＴフィルム（セラピールＨＰ、東洋メタライジング社製）上に流延し、６０℃で５分間乾燥を行った。乾燥後のシートをＰＥＴから剥離した後に金枠に固定し、さらに１２０℃で５分間、１５０℃で１０分間乾燥し、厚み２０μｍのフィルム状接着剤を得た。このフィルム状接着剤は、２００℃×１時間での加熱処理を行う前後どちらにおいても、十分な柔軟性を有していた。
【００６８】
実施例及び比較例の評価結果を表１に示す。表１に示すように、本発明のフィルム状接着剤ならびに接着性積層部材は、低温、低圧下で接着層硬化物と仮圧着が可能であった。スチレン誘導体および／またはエポキシ樹脂を用いない比較例のフィルム状接着剤では、仮圧着性とエポキシ樹脂部数（フィルム柔軟性）のバランスを取ることが困難であった。
【表１】

【００６９】
【発明の効果】
本発明のフィルム状接着剤ならびに接着性積層部材は、低温、低圧下で仮接着が可能であり、接着層硬化物と繰り返しラミネートすることができ、本圧着時には高い接着強度を示すことができる。加えて優れた耐熱性、加工性、接着性を示す。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film adhesive having improved temporary workability at low temperatures and low pressures, and a laminated member obtained by laminating the adhesive. The film adhesive and laminated member of the present invention are useful in laminated materials that require low-temperature pressure bonding properties, heat resistance, and adhesiveness, including multilayer flexible printed circuit boards.
[0002]
[Prior art]
In recent years, electronic devices have been improved in function, performance, and size, and accordingly, electronic components used have been required to be reduced in size and weight. Therefore, semiconductor device packaging methods and wiring materials or wiring components for mounting them have been required to have higher density, higher functionality, and higher performance. In particular, it is excellent in heat resistance, electrical reliability, and adhesiveness that can be suitably used as high-density mounting materials such as semiconductor packages, COL and LOC packages, MCM (Multi Chip Module), and printed wiring board materials such as multilayer FPC. Materials are needed. In particular, in multilayer FPCs that have been actively used for small electronic devices such as cellular phones in recent years, the market is attracting attention to polyimide-based adhesive materials as materials that replace conventional epoxy-impregnated prepregs.
[0003]
Multi-layer FPC may be bonded with low adhesive strength (hereinafter referred to as provisional pressure bonding) at a lower temperature and pressure conditions than the main pressure bonding as an alignment before the main pressure bonding between the layers in the manufacturing process. In a polyimide-based adhesive material that requires high temperature and high pressure for development, it is difficult to perform temporary pressure bonding at low temperature and low pressure, and the adhesive strength at the time of main pressure bonding is not sufficient.
[0004]
As a means for causing the polyimide-based adhesive to exhibit adhesiveness at a relatively low temperature and high adhesive strength, for example, blending a soluble thermoplastic polyimide and an epoxy resin as disclosed in JP-A-2000-109645 can be mentioned. It is done. Since the adhesive produced by this method has both the heat resistance of polyimide and the low-temperature processability of epoxy resin, it has excellent heat resistance while realizing high adhesive strength at a relatively low temperature.
[0005]
[Problems to be solved by the invention]
However, in this application, provisional press-bonding properties for processing at a lower temperature and lower pressure are also required, and thus further low-temperature workability is required. Even the above-mentioned blend type adhesive has a certain degree of low temperature temporary pressure bonding property. However, in order to develop temporary pressure bonding property to the cured adhesive layer at a lower temperature, for example, 120 ° C. or less, the glass transition temperature of thermoplastic polyimide ( It is necessary to significantly reduce Tg) or increase the proportion of epoxy resin. If it does so, there existed a problem that the heat resistance and the softness | flexibility which are the strong points of a polyimide-type material were impaired.
[0006]
[Means for Solving the Problems]
Accordingly, the present inventors provide a film-like adhesive and an adhesive laminated member that can solve the above-mentioned problems and can be temporarily pressure-bonded at a low temperature and a low pressure without impairing the heat resistance that is an advantage of the polyimide-based material. As a result of intensive studies aimed at achieving the above, the present invention has been completed.
[0007]
The gist of the present invention is that the main component is a thermoplastic polyimide resin and an epoxy resin, and a styrene derivative or an oligomer thereof., Epoxy hardenerAnd an adhesive laminate member obtained by laminating the adhesive on at least one side of an insulating film made of polyimide. Furthermore, the film adhesive and the laminated member have a temperature of 120 ° C. or lower and a pressure of 5 kgf / cm.²In the following, provisional pressure bonding is possible under the condition of a linear velocity of 0.5 m / min or less.TemporaryCrimping is possible.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The film adhesive of the present invention is a thermoplastic polyimide resin.For 100 parts by weightEpoxy resinContains 10 to 100 parts by weight, At least one of a styrene derivative represented by the following general formula (1) or an oligomer having a 20-mer or less of the styrene derivative, based on 100 parts by weight of the thermoplastic polyimide resin.0. 1-50 weightIncluding partYesAnd contains epoxy curing agentIt is a film-like adhesive characterized by doing.
[0009]
[Formula 4]

(Wherein R¹Represents a hydrogen atom or a methyl group, R²Independently represents an organic group having 4 or less carbon atoms, a halogen group, or a nitrile group, and n represents 0 or an integer of 1 to 5).
[0010]
The styrene derivative of the present invention may be in either a monomer state or an oligomer state, but when added in the oligomer state, a 20-mer or less, preferably a 10-mer or less is preferred. Specific examples include styrene, styrene oligomer (4 to 6-mer mixture), α-methylstyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, bromostyrene, methoxystyrene, and the like. If the molecular weight of the oligomer is too high, the compatibility with other components may be reduced, which is not preferred, and the monomer state, particularly styrene monomer, is preferred due to availability, thermal characteristics, and the like. As an addition ratio, it is desirable to add 0.1 to 50 parts by weight, preferably 5 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic polyimide. When the amount is too small, the temporary press bonding property at low temperature is not sufficiently exhibited, and when the amount is too large, the heat resistance is poor. In addition, in order to improve compatibility with other components, it is preferable to add in a state diluted with an organic solvent. The type of the organic solvent is not particularly limited, but it is preferable to use the same organic solvent as the other components.
[0011]
By using a styrene derivative or oligomer having thermoplasticity as in the present invention, a conventional thermoplastic polyimide and epoxy resin blend type can be obtained without significantly reducing the Tg of the thermoplastic polyimide and greatly increasing the proportion of the epoxy resin. It has become possible to develop provisional pressure bonding at a lower temperature than the adhesive. That is, by introducing a styrene derivative or oligomer, the apparent glass transition temperature (Tg) of the adhesive can be lowered, and temporary press bonding at low temperature and low pressure is exhibited. Moreover, since it is not necessary to increase the number of epoxy parts extremely, the softness | flexibility in a single layer sheet state can be maintained, and high adhesiveness is shown at the time of this crimping | compression-bonding. Therefore, a film-like adhesive having an excellent balance of heat resistance, flexibility and temporary pressure bonding property can be obtained.
[0012]
The thermoplastic polyimide used for the film-like adhesive of the present invention desirably has a Tg of 200 ° C. or lower in order to develop temporary pressure bonding properties at low temperature and low pressure. When Tg is higher than 200 ° C., higher processing temperature and pressure are required. If the proportion of epoxy resin or styrene derivative is increased to compensate for this, it becomes difficult to achieve both heat resistance and processability.
[0013]
Furthermore, it is desirable that the thermoplastic polyimide used in the film adhesive of the present invention exhibits a solubility of 10% or more in solid content concentration in a cyclic ether solvent. By using a cyclic ether solvent, the solvent can be removed at a relatively low temperature after application of the adhesive solution. When only a high boiling point solvent such as N, N-dimethylformamide or N-methyl-2-pyrrolidone was used, it was difficult to balance the B-stage state of the epoxy resin and the residual solvent. However, by using a cyclic ether solvent, it is easy to remove the solvent from the film, and it is possible to express various physical properties even when drying conditions that significantly reduce the residual solvent are applied.
[0014]
As the thermoplastic polyimide, at least one of an ester dianhydride represented by the following general formula (2) and a diamine compound represented by the following general formula (3) is used.
[0015]
[Chemical formula 5]

(Wherein X is — (CH₂)_j-Or a divalent organic group containing an aromatic ring. j is an integer from 1 to 10. )
[0016]
[Chemical 6]

(In the formula, Y is independently -C (= O)-, -SO.₂-, -O-, -S-,-(CH₂)_k-, -NHCO-, -C (CH_Three)₂-, -C (CF_Three)₂-, -C (= O) O-, or a single bond is shown. k and m are integers of 1 or more and 5 or less. ).
[0017]
As a compound having a structure similar to that of the diamine represented by the general formula (3), there may be one in which an amino group is bonded to an ortho position or a para position other than the meta position. It is preferable to be in the meta position. By having an amino group at the meta position, the solubility of the produced polyimide in an organic solvent becomes better, and an adhesive solution having excellent processability can be obtained. The diamine represented by the general formula (3) can be used alone or in combination.
[0018]
These acid dianhydrides and diamines are each preferably used in an amount of 50 mol% or more, more preferably 80 mol% or more, and particularly preferably 100 mol%. When the amount is less than 50 mol%, the solubility in an organic solvent is not sufficiently exhibited.
[0019]
Specific examples of the ester dianhydride represented by the general formula (2) include 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride. , P-phenylenebis (trimellitic acid monoester anhydride), 3,3 ′, 4,4′-ethylene glycol benzoate tetracarboxylic dianhydride, 4,4′-biphenylenebis (trimellitic acid monoester anhydride) Product), 1,4-naphthalenebis (trimellitic acid monoester anhydride), 1,2-ethylenebis (trimellitic acid monoester anhydride), 1,3-trimethylenebis (trimellitic acid monoester anhydride) ), 1,4-tetramethylene bis (trimellitic acid monoester anhydride), 1,5-pentamethylene bis (trimellitic acid monoester anhydride) , 1,6-hexamethylene bis although (trimellitic acid monoester anhydride), etc., the following general formula (4):
[0020]
[Chemical 7]

2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ', 4,4'-tetracarboxylic dianhydride represented by the following general formula (5):
[0021]
[Chemical 8]

3,3 ′, 4,4′-ethylene glycol benzoate tetracarboxylic dianhydride represented by the formula is particularly preferred.
[0022]
The thermoplastic polyimide resin used for the film adhesive according to the present invention is obtained by dehydrating and ring-closing the polyamic acid polymer which is a precursor thereof. The polyamic acid solution contains an ester dianhydride represented by the general formula (2) and one or more diamines represented by the general formula (3) in an inert atmosphere such as argon or nitrogen. It is obtained by polymerizing in an organic polar solvent by using 50 mol% or more of each component, using the total acid dianhydride and the total diamine so as to be substantially equimolar.
[0023]
The order of addition of each monomer is not particularly limited, and the acid dianhydride component may be added to the organic polar solvent in advance, and the diamine component may be added to form a polyamic acid polymer solution. An appropriate amount is added to the solvent first, then acid dianhydride is added, and finally the remaining diamine component is added to form a solution of the polyamic acid polymer. There are various other addition methods known to those skilled in the art.
[0024]
The polyamic acid polymer obtained above is dehydrated and closed by a thermal or chemical method to obtain a polyimide resin. Examples of the imidization method include a thermal method in which a polyamic acid solution is heat-treated and dehydrated, and a chemical method in which dehydration is performed using a dehydrating agent.
[0025]
Examples of the dehydrating agent by the chemical method include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine and isoquinoline.
[0026]
The thermoplastic polyimide obtained as described above can be used as a solution as it is. Alternatively, the solvent used in the polymerization of the polyamic acid dissolves well, but the polyimide solution is poured into a poor solvent in which the polyimide is difficult to dissolve, and the polyimide resin is precipitated and the unreacted monomer is removed and purified, dried and solid The polyimide resin can be used as appropriate for the adhesive solution of the present invention.
[0027]
Examples of the thermal method include a method in which after polyamic acid is polymerized, it is put into a vacuum oven, imidized by heating under reduced pressure, and taken out as a solid polyimide resin.
[0028]
Since the film adhesive of this invention contains the epoxy resin in the component, the further excellent low temperature workability is provided to the outstanding heat resistance which a polyimide has. Examples of the epoxy resin used include bisphenol A type resins such as Epicoat 828 (manufactured by Yuka Shell), orthocresol novolak resins such as 180S65 (manufactured by Yuka Shell), 157S70 (manufactured by Yuka Shell), etc. Bisphenol A novolak resin, trishydroxyphenylmethane novolak resin such as 1032H60 (manufactured by Yuka Shell), naphthalene aralkyl novolak resin such as ESN375, tetraphenylolethane 1031S (manufactured by Yuka Shell), YGD414S (Tohto Kasei), Glycidylamines such as trishydroxyphenylmethane EPPN502H (Nippon Kayaku), special bisphenol VG3101L (Mitsui Chemicals), special naphthol NC7000 (Nippon Kayaku), TETRAD-X, TETRAD-C (manufactured by Mitsubishi Gas Chemical) Such as resin and the like.
[0029]
The mixing ratio of the epoxy resin is 10 to 100 parts by weight, preferably 20 to 70 parts by weight, with respect to 100 parts by weight of the thermoplastic polyimide resin. If the amount is too small, the temporary press bonding property is not sufficiently exhibited, and if the amount is too large, the flexibility and the heat resistance are inferior.
[0030]
It is preferable to add an epoxy curing agent or a curing accelerator to the adhesive. As an epoxy hardening | curing agent, the commercially available thing which contains 3, 3- diamino diphenyl sulfone, 4, 4- diaminophenyl sulfone etc. can be used, for example, It does not specifically limit. Examples of the curing accelerator include imidazole compounds such as 2-alkylimidazole, 2-alkyl-4-methylimidazole, 2-alkyl-4-ethylimidazole, 1- (2-cyanoethyl) -2-alkylimidazole, 2-phenyl. Examples include imidazole, 2,4-diphenylimidazole, 2-phenyl-4-methylimidazole (the alkyl group preferably has 1 to 4 carbon atoms). Other curing accelerators include acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, and the like. Still other curing accelerators include amine-based materials such as diethylenetriamine, triethylenetetramine, metaxylenediamine, and diaminephenylmethane. These may be used alone or in combination of two or more. Furthermore, various coupling agents can be added to improve water absorption, heat resistance, adhesiveness, and the like.
[0031]
The film adhesive of the present invention comprises an adhesive solution obtained by dissolving the thermoplastic polyimide resin, styrene derivative or oligomer, epoxy resin, and curing agent thereof in an organic solvent, a support such as a polyethylene terephthalate (PET) film, and the like. It is obtained by peeling off after coating and drying on the polymer film.
[0032]
The adhesive laminated member of the present invention is obtained by casting or applying the adhesive solution on at least one surface of an insulating film made of polyimide, and then drying. Moreover, since the film adhesive of this invention is a single layer film of a polyimide-type adhesive agent, this can be laminated with a polyimide film and it can also be used as an adhesive laminated member of the same structure.
[0033]
As an organic solvent for dissolving each component constituting the adhesive, the temperature of the drying process can be lowered, so that the curing of the thermosetting resin does not proceed excessively, and a decrease in physical properties due to residual solvent can be suppressed. It is preferable to use a cyclic ether solvent having a boiling point as a main component. Examples of the cyclic ether solvent include tetrahydrofuran (THF), 1,4-dioxane, dioxolane and the like. These ether solvents are used alone or in combination or in combination with an organic polar solvent. For example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide Is mentioned. The type, number, and order of mixing of the solvents to be combined are not particularly limited, but the ether solvent is preferably contained in an amount of 30% by weight or more, more preferably 60% by weight or more based on the total amount of the solvent. By dissolving the above components in these solvents, an adhesive solution is obtained. At this time, after the thermoplastic polyimide is dissolved in a solvent, the remaining components may be added and used as an adhesive solution, or after each component is dissolved in a solvent, the solutions are mixed and used. May be. If it is difficult to dissolve the thermoplastic polyimide resin, heating is performed as necessary. However, since the cyclic ether solvent has a low boiling point and easily volatilizes, the heating temperature and the heating time are kept to the minimum necessary. Further, when dissolving the thermosetting resin, it is preferable to refrain from heating as much as possible.
[0034]
Examples of the method for applying the adhesive layer include, but are not particularly limited to, an applicator, a bar coater, a spin coater, and a gravure coater. Whichever method is used, the thickness of the adhesive layer is preferably about 3 to 60 μm. The drying process after applying the adhesive is not particularly limited, but when it has a certain thickness, in order to prevent foaming, it is preferable to perform drying while gradually raising the temperature from a low temperature. Further, although depending on the drying time, it is preferable to keep the drying temperature at 200 ° C. or lower in order to prevent the curing of the epoxy component from proceeding excessively.
[0035]
In the laminated member of the present invention, a release film is disposed on at least one side as necessary. Examples of the release film used include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyphenylene sulfide (PPS). Since the thickness of the release film is selected according to the use situation, it is not limited here, but in order to facilitate the peeling during the processing step, it is preferable that the surface in contact with the adhesive layer is subjected to a peeling treatment. . Examples of the treatment method include silicon treatment, alkyd treatment, fluorine treatment, and polyolefin treatment, but are not particularly limited. The adhesive strength of the release film to the adhesive layer of the film-like adhesive laminate member is desirably in the range of 1 to 50 gf / cm, and more desirably 5 to 20 gf / cm. If the adhesive strength is too low, there is a possibility of peeling before use, and if the adhesive strength is too high, smooth peeling becomes difficult. The method for laminating the release film is not particularly limited, but in order to prevent wrinkles and bubbles from entering, it is desirable to apply them while applying a certain amount of pressure. Moreover, in order to avoid that a release film adhere | attaches more than necessary, it is desirable to keep a lamination temperature below 140 degreeC.
[0036]
The film adhesive and laminated member of the present invention obtained as described above have characteristics that are suitably used for laminated materials such as multilayer FPC. Specifically, the temperature is 120 ° C. or less and the pressure is 5 kgf / cm without impairing the heat resistance.²In the following, provisional pressure bonding is possible under conditions of a linear velocity of 0.5 m / min or less at low temperature and low pressure, and the strength is 10 gf / cm or more and 100 gf / cm or less. Temporary crimping is possible. In order to use repeatedly, the temporary pressure bonding strength is preferably 10 gf / cm or more and 100 gf / cm or less, and if it is 10 gf / cm or less, it does not cause temporary displacement, and When it is 100 gf / cm or more, it becomes difficult to peel off, causing a problem.
[0037]
The film-like adhesive and laminated member according to the present invention can be bonded at a relatively low temperature not only for temporary pressure bonding but also for metal pressure bonding such as copper foil and polyimide film, and can be processed at the time of use. Excellent. The bonding conditions in this case may be the bonding conditions that are necessary and sufficient for adhesive curing. Specifically, the heating temperature is 150 to 250 ° C., and the pressure is 1 to 100 kgf / cm.²It is preferable to heat and press under conditions of heating time of about 5 to 20 minutes. Moreover, after-curing may be performed as necessary to sufficiently advance the curing reaction of the epoxy component. The after-curing conditions are preferably 150 to 250 ° C. and about 1 to 3 hours, but are not particularly limited.
[0038]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. The present invention is not limited to these examples.
[0039]
The determination of the pre-bonding temperature and the evaluation method of the final peel strength in Examples and Comparative Examples are as follows.
[0040]
(Determination of provisional crimping temperature)
The temporary pressure bonding temperature between the film adhesive or laminated member and their cured product was evaluated by the following procedure.
1) The film adhesives and laminated members obtained in Examples and Comparative Examples are dried at 200 ° C. for 1 hour to cure the adhesives to obtain cured members.
2) The said hardening member is piled up on the single side | surface of each film adhesive and a laminated member, and it bonds together with a heat laminating apparatus. As the laminating apparatus, a thermal laminating apparatus (roll material: silicon rubber) having one pair each of the present laminating roll and the slow cooling laminating roll was used.
[0041]
Temperature: Laminate in increments of 10 ° C from 90 to 150 ° C
Pressure: 3kgf / cm²
Speed: 0.3m / min
3) Measure the peel strength with the cured member.
4) The lowest laminating temperature at which an adhesive strength of 10 gf / cm or more is expressed is set as a temporary pressure bonding temperature. The peel strength was measured according to JIS C6481. However, each film-like adhesive and laminated member was peeled off with a width of 1 cm instead of the conductor and measured.
[0042]
(Final peel strength)
The peel strength when the copper foil was bonded was measured according to the following procedure. Each film adhesive or laminated member and 18 μm rolled copper foil are superposed, temperature 200 ° C., pressure 30 kgf / cm.²And heated and pressurized for 5 minutes to obtain a copper-clad flexible laminate. The peel strength of the obtained copper-clad flexible laminate was measured according to JIS C6481. However, the conductor width was measured at 3 mm.
[0043]
(Synthesis Example 1) 327 g of N, N-dimethylformamide (hereinafter referred to as DMF) and 0.20 mol of 1,3-bis (3-aminophenoxy) benzene (hereinafter referred to as APB) were added to a glass flask having a capacity of 1000 ml. While stirring in a nitrogen atmosphere, 0.20 mol of 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride (hereinafter referred to as ESDA) was added. Slowly added. The mixture was stirred for 30 minutes in an ice bath, and when the viscosity reached 1500 poise, the stirring was stopped to obtain a polyamic acid solution.
[0044]
300 g of this polyamic acid solution was transferred to a Teflon (registered trademark) -coated vat and heated under reduced pressure in a vacuum oven at 200 ° C. for 3 hours at a pressure of 5 mmHg (about 0.007 atm). Taking out from the vacuum oven, 85 g of thermoplastic polyimide was obtained.
[0045]
Synthesis Example 2 388 g of DMF, 0.19 mol of 3,3′-bis (aminophenoxyphenyl) sulfone (hereinafter referred to as BAPS-M), 3,3′-dihydroxy-4, 0.01 mol of 4′-diaminobiphenyl (hereinafter referred to as HAB) was added, and 3,3 ′, 4,4′-ethylene glycol benzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG) while stirring under a nitrogen atmosphere. Was gradually added in an amount of 0.20 mol. The mixture was stirred for 30 minutes in an ice bath, and when the viscosity reached 1500 poise, the stirring was stopped to obtain a polyamic acid solution.
[0046]
300 g of this polyamic acid solution was transferred to a Teflon (registered trademark) -coated vat and heated under reduced pressure in a vacuum oven at 200 ° C. for 3 hours at a pressure of 5 mmHg (about 0.007 atm). Taking out from the vacuum oven, 85 g of thermoplastic polyimide was obtained.
[0047]
Synthesis Example 3 To a glass flask having a capacity of 1000 ml, 326 g of DMF, 0.19 mol of APB, and 0.01 mol of HAB were added, and 0.20 mol of TMEG was gradually added while stirring in a nitrogen atmosphere. The mixture was stirred for 30 minutes in an ice bath, and when the viscosity reached 1500 poise, the stirring was stopped to obtain a polyamic acid solution.
[0048]
300 g of this polyamic acid solution was transferred to a vat coated with Teflon (registered trademark), and heated under reduced pressure in a vacuum oven at 180 ° C. for 3 hours at a pressure of 5 mmHg (about 0.007 atm). Taking out from the vacuum oven, 84 g of thermoplastic polyimide was obtained.
[0049]
Example 1 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). 70 g of this varnish was treated with 30 g of a dioxolane solution (SC = 30%) of Epicoat 1032H60 (manufactured by Yuka Shell), 10 g of a dioxolane solution of styrene monomer (SC 30%), 4,4′-diaminodiphenyl sulfone (hereinafter referred to as 4,4). 13.5 g of a dioxolane solution (referred to as 4′-DDS) (SC = 20%) was added, and the mixture was stirred and mixed uniformly to obtain an adhesive solution.
[0050]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the curing treatment at 200 ° C. for 1 hour.
[0051]
(Example 2) 30 g of the polyimide powder obtained in Synthesis Example 2 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). To 85 g of this varnish, 25 g of a dioxolane solution (SC = 30%) of NC-3000 (manufactured by Nippon Kayaku), 5 g of a dioxolane solution of styrene monomer (SC = 30%), and a dioxolane solution of 4,4′-DDS (SC = 20%) was added, and the mixture was stirred and mixed uniformly to obtain an adhesive solution.
[0052]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the curing treatment at 200 ° C. for 1 hour.
[0053]
(Example 3) 30 g of the polyimide powder obtained in Synthesis Example 3 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). 70 g of this varnish was mixed with 30 g of a dioxolane solution (SC = 30%) of Epicoat 1032H60 (manufactured by Yuka Shell), 10 g of a dioxolane solution of styrene monomer (SC = 30%), and a dioxolane solution of 4,4′-DDS (SC = 20%) was added, and the mixture was stirred and mixed uniformly to obtain an adhesive solution.
[0054]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the curing treatment at 200 ° C. for 1 hour.
[0055]
(Example 4) 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). 70 g of this varnish, 30 g of a dioxolane solution (SC = 30%) of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Inc.), 5 g of a dioxolane solution (SC = 30%) of an oligomer which is a mixture of tetramer to hexamer of styrene, 13.5 g of a 4,4′-DDS dioxolane solution (SC = 20%) was added, and the mixture was stirred and mixed uniformly to obtain an adhesive solution.
[0056]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the curing treatment at 200 ° C. for 1 hour.
[0057]
(Example 5) An adhesive solution obtained in the same manner as in Example 1 was cast on a 12.5 μm-thick polyimide film (Apical 12.5 NPI, Kaneka Chemical Co., Ltd.), and at 60 ° C. for 2 minutes. Dried. The other side was cast in the same manner and dried at 60 ° C. for 2 minutes. Further, this film was fixed to a metal frame and dried at 150 ° C. for 5 minutes to obtain a film-like laminated member having a total thickness of 22.5 μm.
[0058]
(Example 6) An adhesive solution obtained in the same manner as in Example 2 was cast on a 12.5 μm-thick polyimide film (Apical 12.5 NPI, manufactured by Kaneka Chemical Co., Ltd.), and at 60 ° C. for 2 minutes. Dried. The other side was cast in the same manner and dried at 60 ° C. for 2 minutes. Further, this film was fixed to a metal frame and dried at 150 ° C. for 5 minutes to obtain a film-like laminated member having a total thickness of 22.5 μm.
[0059]
Comparative Example 1 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). To 70 g of this varnish, 30 g of a dioxolane solution (SC = 30%) of Epicoat 1032H60 (manufactured by Yuka Shell) and 13.5 g of a dioxolane solution (SC = 20%) of 4,4′-DDS were added and stirred. And uniformly mixed to obtain an adhesive solution.
[0060]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the curing treatment at 200 ° C. for 1 hour.
[0061]
Comparative Example 2 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). To 40 g of this varnish, 60 g of a dioxolane solution (SC = 30%) of Epicoat 1032H60 (manufactured by Yuka Shell Co., Ltd.) and 27 g of a dioxolane solution (SC = 20%) of 4,4′-DDS were added and stirred to make uniform To obtain an adhesive solution.
[0062]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive was brittle after the curing treatment at 200 ° C. × 1 hour, and its flexibility was insufficient.
[0063]
Comparative Example 3 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). To 70 g of this varnish, 30 g of a dioxolane solution (SC = 30%) of Epicoat 1032H60 (manufactured by Yuka Shell) and 13.5 g of a dioxolane solution (SC = 20%) of 4,4′-DDS were added and stirred. And uniformly mixed to obtain an adhesive solution.
[0064]
The adhesive solution obtained above was cast on a 12.5 μm-thick polyimide film (Apical 12.5 NPI, Kaneka Chemical Co., Ltd.) and dried at 60 ° C. for 2 minutes. The other side was cast in the same manner and dried at 60 ° C. for 2 minutes. Further, this film was fixed to a metal frame and dried at 150 ° C. for 5 minutes to obtain a film-like laminated member having a total thickness of 22.5 μm.
[0065]
Comparative Example 4 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). 10 g of a dioxolane solution of styrene monomer (SC = 30%) was added to 70 g of this varnish, and the mixture was stirred and mixed uniformly to obtain an adhesive solution.
[0066]
The adhesive solution obtained above was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the heat treatment at 200 ° C. × 1 hour.
[0067]
(Comparative Example 5) 30 g of the polyimide powder obtained in Synthesis Example 1 was added to 70 g of dioxolane and dissolved by stirring to obtain a varnish (SC = 30%). The varnish was cast on a 25 μm thick PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.), and dried at 60 ° C. for 5 minutes. The dried sheet was peeled from the PET and then fixed to a metal frame, and further dried at 120 ° C. for 5 minutes and 150 ° C. for 10 minutes to obtain a film adhesive having a thickness of 20 μm. This film adhesive had sufficient flexibility both before and after the heat treatment at 200 ° C. × 1 hour.
[0068]
The evaluation results of Examples and Comparative Examples are shown in Table 1. As shown in Table 1, the film-like adhesive and the adhesive laminated member of the present invention were capable of temporary pressure bonding with the cured adhesive layer at low temperature and low pressure. In the film adhesive of the comparative example which does not use a styrene derivative and / or an epoxy resin, it was difficult to balance the temporary pressure bonding property and the number of epoxy resin parts (film flexibility).
[Table 1]

[0069]
【The invention's effect】
The film-like adhesive and the adhesive laminated member of the present invention can be temporarily bonded under low temperature and low pressure, can be repeatedly laminated with a cured adhesive layer, and can exhibit high adhesive strength at the time of final pressing. In addition, it exhibits excellent heat resistance, workability, and adhesion.

Claims (7)

10 to 100 parts by weight of epoxy resin with respect to 100 parts by weight of thermoplastic polyimide resin, and at least one of styrene derivatives represented by the following general formula (1) or oligomers of 20 or less mers of the styrene derivatives It was converted, with respect to 100 parts by weight of the thermoplastic polyimide resin 0. 1-50 parts by weight containing organic, film-like adhesive agent characterized by containing an epoxy curing agent:

(Wherein R ¹ represents a hydrogen atom or a methyl group, R ² independently represents an organic group having 4 or less carbon atoms, a halogen group or a nitrile group, and n represents 0 or an integer of 1 to 5) ). The film adhesive according to claim 1, wherein the styrene derivative is a styrene monomer. The thermoplastic polyimide resin has a glass transition temperature (Tg) of 200 ° C. or less and a solubility of 10% or more in a solid content concentration (SC) in a cyclic ether solvent of tetrahydrofuran, 1,4-dioxane or dioxolane . The film adhesive according to any one of claims 1 and 2, wherein The thermoplastic polyimide has the following general formula (2):

(Wherein X represents — (CH ₂ ) _j — or a divalent organic group containing an aromatic ring, j is an integer of 1 or more and 10 or less), and The following general formula (3):

(In the formula, Y is independently —C (═O) —, —SO ₂ —, —O—, —S—, — (CH ₂ ) _k —, —NHCO—, —C (CH ₃ ) _2. -, -C (CF ₃ ) _2- , -C (= O) O-, or a single bond. K and m are integers of 1 or more and 5 or less. The film adhesive according to any one of claims 1 to 3, wherein the film is obtained using 50 mol% or more of each component. The film adhesive according to claim 1, wherein the adhesive has a thickness of 3 to 60 μm. Temporary pressure bonding is possible with a pressure strength of 10 gf / cm or more and 100 gf / cm or less against a multilayer FPC laminate material under conditions of a temperature of 120 ° C. or less, a pressure of 5 kgf / cm ² or less, and a linear velocity of 0.5 m / min or less , and the temporary post-bonding also peeling, characterized in that it is a re Dokari crimping, film-like adhesive according to any one of claims 1 to 5. It is an adhesive laminated member formed by laminating an adhesive layer on at least one surface of an insulating film made of polyimide, and the adhesive layer is the film adhesive according to any one of claims 1 to 6. The laminated member characterized by the above-mentioned.