JP4259055B2 - Anisotropic conductive film - Google Patents

Description

（式中、Ｒは水素原子又はアルキル基、Ｒ’はアルケニル基等の脂肪族不飽和基又はこれを含有する基を示す。）
【００２４】
なお、上記式（１）において、ビニルアルコール単位Ｂは好ましくは３〜７０モル％、より好ましくは５〜５０モル％、更に好ましくは５〜３０モル％であり、３モル％より少ないと酸変性の反応性が悪く、７０モル％より多いと耐熱性、耐湿性が劣る場合が生じる。
【００２５】
本発明においては、接着剤樹脂組成物は、接着剤の主成分となる溶剤（ここで、溶剤とは例えば、アセトン、ＭＥＫ、酢酸エチル、酢酸セロソルブ、ジオキサン、ＴＨＦ、ベンゼン、シクロヘキサノン、ソルベッソ１００等の有機溶剤を指す。）に可溶なポリエステル不飽和化合物であってもよい。このポリエステル不飽和化合物は、多塩基酸と多価アルコールとを反応させることによって得られる不飽和ポリエステルと、溶剤に可溶な飽和共重合ポリエステルに（メタ）アクリロキシ基を導入した化合物などのラジカル反応硬化性のポリエステル不飽和化合物である。即ち、このポリエステル不飽和化合物とは
▲１▼ 不飽和ポリエステル化合物
▲２▼ 飽和ポリエステルに（メタ）アクリロキシ基及び／又はメタクリロキシ基を導入した化合物
の２種類である。
【００２６】
ここで、溶剤に可溶な飽和共重合ポリエステルとしては、テレフタル酸とエチレングリコール及び／又は１，４−ブタンジオールを主たる構成成分とし、全酸成分の５〜５０モル％のフタル酸、イソフタル酸、アジピン酸、セバシン酸、ドデカン酸等の酸成分及び／又は全アルコール成分の５〜５０モル％の量で１，３−プロパンジオール、２，２−ジメチル−１，３−プロパンジオール、２，２−ジエチル−１，３−プロパンジオール、２−エチル−２−ブチル−１，３−プロパンジオール、１，６−ヘキサンジオール、１，９−ノナンジオール等のアルコール成分を１種又は２種以上で共重合したものである。
【００２７】
このような飽和共重合ポリエステルへの（メタ）アクリロキシ基の導入方法としては、
（１） イソシアネートアルキル（メタ）アクリレートを前記飽和共重合ポリエステルの水酸基と反応させる方法、
（２） アルキル（メタ）アクリレートと前記飽和共重合ポリエステルの水酸基とのエステル交換反応による方法、
（３） ジイソシアネート化合物とヒドロキシアルキル（メタ）アクリレートとの反応によるイソシアナートアルキル（メタ）アクリレートを前記飽和共重合ポリエステルの水酸基と反応させる方法
を採用することができる。
【００２８】
本発明では、このようなベース樹脂のポリイミド樹脂等への接着性を向上させるために、リン酸系化合物含有層においては、ベース樹脂に対しリン酸系化合物を配合する。リン酸系化合物としては、酸価が１００〜８００特に５００〜７００のものが好ましい。酸価が１００以下であると接着力向上効果が低く、８００以上であると、酸性度が高すぎ、導通特性、貯蔵安定性が極めて悪くなるおそれがある。リン酸系化合物としては、酸性リン酸エステル、亜リン酸エステル、リン酸塩が好適であり、具体的にはメチルアシッドホスフェート、ブチルアシッドホスフェート、イソデシルアシッドホスフェート、モノブチルホスフェート、ジフェニルホスホロクロリデート、ジフェニル−２−メタクリロイルオキシエチルホスフェート、２−メタクリロイロキシエチルアシッドホスフェート、リン酸クロライドが例示される。これらのリン酸系化合物は１種を単独で用いても良く、２種以上を併用しても良い。
【００２９】
このリン酸系化合物の配合量は、接着剤樹脂組成物１００重量部に対し０．１〜５０重量部（ｐｈｒ）である。特に０．３〜４重量部が好ましい。この配合量が０．１ｐｈｒ未満であると接着力向上効果が低く、５０ｐｈｒを超えると、酸性度が高すぎ、導通特性、貯蔵安定性が極めて悪くなるおそれがある。
【００３０】
本発明では、異方性導電フィルムのＩＴＯ接着予定面側はリン酸系化合物非含有層とし、それと反対側をリン酸系化合物含有層とし、このリン酸系化合物含有層をポリイミド等と接着させる。リン酸系化合物非含有層の層厚さｔ_０とリン酸系化合物含有層の層厚さｔ_１との比ｔ_０／ｔ_１は０．１〜１０特に０．５〜２程度が好ましい。異方性導電フィルムの全体厚さは１０〜６０μｍ特に１５〜４０μｍ程度が好ましい。
【００３１】
本発明に係る接着剤樹脂組成物においては、異方性導電フィルムの接着性の向上のために、メラミン系樹脂及びアルキド樹脂の少なくとも１種を配合してもよい。
【００３３】
メラミン系樹脂としては、例えば、メラミン樹脂、イソブチル化メラミン樹脂、ｎ−ブチル化メラミン樹脂等のブチル化メラミン樹脂、メチル化メラミン樹脂、等の１種又は２種以上が挙げられる。このようなメラミン系樹脂は、前記ベース樹脂１００重量部に対して１〜２００重量部、特に１〜１００重量部配合するのが好ましい。
【００３４】
アルキド樹脂としては、純粋アルキド樹脂、変性アルキド樹脂のいずれでも良いが、オイルフリー、或いは短油性ないし中油性のものが好ましい。このようなアルキド樹脂は、前記ベース樹脂１００重量部に対して０．０１〜１０重量部、特に０．５〜５重量部配合するのが好ましい。
【００３５】
この接着剤樹脂組成物には、接着層への気泡の混入を防止してより一層高い導電性と接着力を確保するために尿素系樹脂を配合してもよい。この尿素系樹脂としては、尿素樹脂、ブチル化尿素系樹脂等を用いることができる。なお、同様の目的でフェノール樹脂、ブチル化ベンゾグアナミン樹脂、エポキシ樹脂等を用いることができる。
【００３６】
尿素系樹脂等の気泡混入防止のための樹脂は、ベース樹脂１００重量部に対して０．０１〜１０重量部、特に０．５〜５重量部とするのが好ましい。
【００３７】
本発明においては、異方性導電フィルムの物性（機械的強度、接着性、光学的特性、耐熱性、耐湿性、耐候性、架橋速度等）の改良や調節のために、接着剤樹脂組成物にアクリロキシ基、メタクリロキシ基又はエポキシ基を有する反応性化合物（モノマー）を配合することが好ましい。この反応性化合物としては、アクリル酸又はメタクリル酸誘導体、例えばそのエステル及びアミドが最も一般的であり、エステル残基としてはメチル、エチル、ドデシル、ステアリル、ラウリルのようなアルキル基のほかに、シクロヘキシル基、テトラヒドロフルフリル基、アミノエチル基、２−ヒドロキシエチル基、３−ヒドロキシプロピル基、３−クロロ−２−ヒドロキシプロピル基等が挙げられる。また、エチレングリコール、トリエチレングリコール、ポリプロピレングリコール、ポリエチレングリコール、トリメチロールプロパン、ペンタエリスリトール等の多官能アルコールとのエステルも同様に用いられる。アミドとしては、ダイアセトンアクリルアミドが代表的である。多官能架橋助剤としては、トリメチロールプロパン、ペンタエリスリトール、グリセリン等のアクリル酸又はメタクリル酸エステル等が挙げられる。また、エポキシ基含有化合物としては、トリグリシジルトリス（２−ヒドロキシエチル）イソシアヌレート、ネオペンチルグリコールジグリシジルエーテル、１，６−ヘキサンジオールジグリシジルエーテル、アリルグリシジルエーテル、２−エチルヘキシルグリシジルエーテル、フェニルグリシジルエーテル、フェノール（ＥＯ）５グリシジルエーテル、ｐ−ｔ−ブチルフェニルグリシジルエーテル、アジピン酸ジグリシジルエステル、フタル酸ジグリシジルエステル、グリシジルメタクリレート、ブチルグリシジルエーテル等が挙げられる。また、エポキシ基を含有するポリマーをアロイ化することによって同様の効果を得ることができる。
【００３８】
これらの反応性化合物は１種又は２種以上の混合物として、前記ベース樹脂１００重量部に対し、通常０．５〜８０重量部、好ましくは０．５〜７０重量部添加して用いられる。この配合量が８０重量部を超えると接着剤の調製時の作業性や成膜性を低下させることがある。
【００３９】
本発明においては、接着剤樹脂組成物が熱硬化型の場合、硬化剤として有機過酸化物を配合するが、この有機過酸化物としては、７０℃以上の温度で分解してラジカルを発生するものであればいずれも使用可能であるが、半減期１０時間の分解温度が５０℃以上のものが好ましく、成膜温度、調製条件、硬化（貼り合わせ）温度、被着体の耐熱性、貯蔵安定性を考慮して選択される。
【００４０】
使用可能な有機過酸化物としては、例えば２，５−ジメチルヘキサン、２，５−ジハイドロパーオキサイド、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキシン３、ジ−ｔ−ブチルパーオキサイド、ｔ−ブチルクミルパーオキサイド、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキサン、ジクミルパーオキサイド、α，α’−ビス（ｔ−ブチルパーオキシイソプロピル）ベンゼン、ｎ−ブチル−４，４’−ビス （ｔ−ブチルパーオキシ）バレレート、１，１−ビス（ｔ−ブチルパーオキシ）シクロヘキサン、１，１−ビス（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、ｔ−ブチルパーオキシベンゾエート、ベンゾイルパーオキサイド、ｔ−ブチルパーオキシアセテート、メチルエチルケトンパーオキサイド、２，５−ジメチルヘキシル−２，５−ビスパーオキシベンゾエート、ブチルハイドロパーオキサイド、ｐ−メンタンハイドロパーオキサイド、ｐ−クロロベンゾイルパーオキサイド、ヒドロキシヘプチルパーオキサイド、クロロヘキサノンパーオキサイド、オクタノイルパーオキサイド、デカノイルパーオキサイド、ラウロイルパーオキサイド、クミルパーオキシオクトエート、サクシニックアシッドパーオキサイド、アセチルパーオキサイド、ｔ−ブチルパーオキシ（２−エチルヘキサノエート）、ｍ−トルオイルパーオキサイド、ｔ−ブチルパーオキシイソブチレート、２，４−ジクロロベンゾイルパーオキサイド等が挙げられる。これらの有機過酸化物は１種を単独で用いても２種以上を併用しても良い。
【００４１】
このような有機過酸化物はベース樹脂１００重量部に対して好ましくは０．１〜１０重量部配合される。
【００４２】
また、本発明においては、接着剤樹脂組成物が光硬化型の場合、光によってラジカルを発生する光増感剤を配合するが、この光増感剤（光重合開始剤）としては、ラジカル光重合開始剤が好適に用いられる。ラジカル光重合開始剤のうち、水素引き抜き型開始剤としてベンゾフェノン、ｏ−ベンゾイル安息香酸メチル、４−ベンゾイル−４’−メチルジフェニルサルファイド、イソプロピルチオキサントン、ジエチルチオキサントン、４−（ジエチルアミノ）安息香酸エチル等が使用可能である。また、ラジカル光重合開始剤のうち、分子内開裂型開始剤としてベンゾインエーテル、ベンゾイルプロピルエーテル、ベンジルジメチルケタール、α―ヒドロキシアルキルフェノン型として、２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オン、１−ヒドロキシシクロヘキシルフェニルケトン、アルキルフェニルグリオキシレート、ジエトキシアセトフェノンが、また、α―アミノアルキルフェノン型として、２−メチル−１−[４−（メチルチオ）フェニル]−２−モルフォリノプロパノン−１、２−ベンジル−２−ジメチルアミノ−１−（４−モルフォリノフェニル）ブタノン−１が、またアシルフォスフィンオキサイド等が用いられる。これらの光増感剤は１種を単独で用いても２種以上を併用しても良い。
【００４３】
このような光増感剤はベース樹脂１００重量部に対して好ましくは０．１〜１０重量部配合される。
【００４４】
接着剤樹脂組成物には、接着促進剤としてシランカップリング剤を添加することが好ましい。シランカップリング剤としては、ビニルトリエトキシシラン、ビニルトリス（β−メトキシエトキシ）シラン、γ−メタクリロキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリエトキシシラン、β−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、ビニルトリクロロシラン、γ−メルカプトプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、Ｎ−β−（アミノエチル）−γ−アミノプロピルトリメトキシシラン等の１種又は２種以上の混合物が用いられる。
【００４５】
これらのシランカップリング剤の添加量は、ベース樹脂１００重量部に対し通常０．０１〜５重量部で充分である。
【００４６】
また、接着剤樹脂組成物には、加工性や貼り合わせ性等の向上の目的で炭化水素樹脂を添加することができる。この場合、添加される炭化水素樹脂は天然樹脂系、合成樹脂系のいずれでもよい。天然樹脂系では、ロジン、ロジン誘導体、テルペン系樹脂が好適に用いられる。ロジンではガム系樹脂、トール油系樹脂、ウッド系樹脂を用いることができる。ロジン誘導体としてはロジンをそれぞれ水素化、不均一化、重合、エステル化、金属塩化したものを用いることができる。テルペン系樹脂ではα−ピネン、β−ピネン等のテルペン系樹脂の他、テルペンフェノール樹脂を用いることができる。また、その他の天然樹脂としてダンマル、コバル、シェラックを用いてもよい。一方、合成樹脂系では石油系樹脂、フェノール系樹脂、キシレン系樹脂が好適に用いられる。石油系樹脂では脂肪族系石油樹脂、芳香族系石油樹脂、脂環族系石油樹脂、共重合系石油樹脂、水素化石油樹脂、純モノマー系石油樹脂、クマロンインデン樹脂を用いることができる。フェノール系樹脂ではアルキルフェノール樹脂、変性フェノール樹脂を用いることができる。キシレン系樹脂ではキシレン樹脂、変性キシレン樹脂を用いることができる。
【００４７】
このような炭化水素樹脂の添加量は適宜選択されるが、ベース樹脂１００重量部に対して１〜２００重量部が好ましく、更に好ましくは５〜１５０重量部である。
【００４８】
以上の添加剤のほか、本発明に係る接着剤樹脂組成物には、老化防止剤、紫外線吸収剤、染料、加工助剤等を本発明の目的に支障をきたさない範囲で用いてもよい。
【００４９】
導電性粒子としては、電気的に良好な導体であれば良く、種々のものを使用することができる。例えば、銅、銀、ニッケル等の金属ないし合金粉末、このような金属又は合金で被覆された樹脂又はセラミック粉体等を使用することができる。また、その形状についても特に制限はなく、りん片状、樹枝状、粒状、ペレット状等の任意の形状をとることができる。
【００５０】
なお、導電性粒子は、弾性率が１．０×１０^７〜１．０×１０^１０Ｐａであるものが好ましい。即ち、プラスチックフィルムを基材とする液晶フィルムなどの被接着体の接続で異方性導電フィルムを使用する場合、導電性粒子として弾性率の高いものを用いると、被接着体にクラックが生じるなどの破壊や圧着後の粒子の弾性変形回復によるスプリングバックなどが発生し、安定した導通性能を得ることができない恐れがあるため、上記弾性率範囲の導電性粒子を用いることが推奨される。これにより、被接着体の破壊を防止し、圧着後の粒子の弾性変形回復によるスプリングバックの発生を抑制し、導電性粒子の接触面積を広くすることが可能になって、より安定した信頼性の高い導通性能を得ることができる。なお、弾性率が１.０×１０^７Ｐａより小さいと、粒子自身の損傷が生じ、導通特性が低下する場合があり、１．０×１０^１０Ｐａより大きいと、スプリングバックの発生が生じる恐れがある。このような導電性粒子としては、上記のような弾性率を有するプラスチック粒子の表面を前述の金属又は合金で被覆したものが好適に用いられる。
【００５１】
本発明において、このような導電性粒子の配合量は、前記ベース樹脂に対して０．１〜１５容量％であることが好ましく、また、この導電性粒子の平均粒径は０．１〜１００μｍであることが好ましい。このように、配合量及び粒径を規定することにより、隣接した回路間で導電性粒子が凝縮し、短絡し難くなり、良好な導電性を得ることができるようになる。
【００５２】
本発明の異方性導電フィルムは、このような導電性粒子を接着剤樹脂組成物中に分散させてなるものである。この導電性粒子を含む接着剤樹脂組成物は、メルトインデックス（ＭＦＲ）が１〜３０００、特に１〜１０００、とりわけ１〜８００であることが好ましく、また、７０℃における流動性が１０^５Ｐａ・ｓ以下であることが好ましく、従って、このようなＭＦＲ及び流動性が得られるように配合を選定することが望ましい。
【００５３】
本発明の異方性導電フィルムは、前記接着剤樹脂組成物と、導電性粒子とを所定の配合で均一に混合し、押出機、ロール等で混練した後、カレンダーロール、Ｔダイ押出、インフレーション等の成膜法により所定の形状に成膜してリン酸系化合物非含有層及びリン酸系化合物含有層を形成し、これらを積層することにより製造することができるが、共押出しによって成膜してもよい。また、リン酸系化合物の非含有層及び含有層はそれぞれ、接着剤樹脂組成物と導電性粒子を溶媒に溶解ないし分散させ、セパレーターの表面に塗付した後、溶媒を蒸発させることによっても成膜することができる。この場合、一方の層を成膜した後、その上に他方の層を上記溶媒蒸着プロセスによって成膜してもよい。なお、成膜に際しては、ブロッキング防止、被着体との圧着を容易にするため等の目的で、エンボス加工を施してもよい。
【００５４】
このようにして得られた異方性導電フィルムによって被着体同士を接着するには、例えば、熱プレスによる貼り合わせ法や、押出機、カレンダーによる直接ラミネート法、フィルムラミネーターによる加熱圧着法等の各種の手法を用いることができる。この際、前記の通り、リン酸系化合物非含有層をＩＴＯ側とする。
【００５５】
本発明の異方性導電フィルムにおける硬化条件としては、熱硬化の場合は、用いる有機過酸化物の種類に依存するが、通常７０〜１７０℃、好ましくは７０〜１５０℃で、通常１０秒〜１２０分、好ましくは２０秒〜６０分である。
【００５６】
光増感剤を用いる光硬化の場合は、光源として紫外〜可視領域に発光する多くのものが採用でき、例えば超高圧、高圧、低圧水銀灯、ケミカルランプ、キセノンランプ、ハロゲンランプ、マーキュリーハロゲンランプ、カーボンアーク灯、白熱灯、レーザー光等が挙げられる。照射時間は、ランプの種類、光源の強さによって一概には決められないが、数十秒〜数十分程度である。
【００５７】
また、硬化促進のために、予め積層体を４０〜１２０℃に加温し、これに紫外線を照射しても良い。
【００５８】
この接着時には、接着方向に１〜４ＭＰａ特に２〜３ＭＰａ程度の圧力を加えることが好ましい。
【００５９】
なお、本発明の異方性導電フィルムは、フィルム厚さ方向に１０Ω以下、特に５Ω以下の導電性を有し、面方向の抵抗は１０^６Ω以上、特に１０^９Ω以上であることが好ましい。
【００６０】
本発明の異方性導電フィルムは、例えばＦＰＣやＴＡＢと液晶パネルのガラス基板上のＩＴＯ端子との接続に好適であるが、その他の用途にも用いることができる本発明の異方性導電フィルムによれば、硬化時に架橋構造が形成されると共に、高い接着性と、優れた耐久性、耐熱性が得られる。
【００６１】
【実施例】
以下、実施例及び比較例を挙げて本発明をより具体的に説明するが、本発明はその要旨を超えない限り、以下の実施例に限定されるものではない。
【００６２】
実施例１
ポリビニルブチラール（電気化学工業社製「デンカＰＶＢ３０００−１」）のトルエン２５重量％溶液を調製し、ポリビニルブチラール１００重量部に対して表１の「ＦＰＣ側」に示す成分を表１に示す量で混合し、これをバーコーターによりセパレーターであるポリテレフタル酸エチレン上に塗布した。トルエン蒸発後、その上に、リン酸系化合物を含まないこと以外は同一調合の溶液を塗布し、幅５ｍｍ、厚さ１５μｍのフィルムを得た。なお、リン酸系化合物含有層の厚さは８μｍ、リン酸系化合物非含有層の厚さは７μｍである。
【００６３】
前記のフィルムを、ＰＥＴ樹脂基板にＳｉＯ_Ｘ膜を介してＩＴＯ端子を形成した基板と、ポリイミド基板に銅箔をパターニングした基板（ＦＰＣ）との接着用として、セパレーターを剥離してモニターで位置決めをし、リン酸系化合物含有層をＦＰＣ側とし、リン酸系化合物非含有層をＩＴＯ側とし、１３０℃で２０秒間、３ＭＰａにおいて加熱圧着した。なお、表１の通り、この実施例ではリン酸系化合物としてモノブチルホスフェート（酸価６７０）を用いている。また、導電性粒子の平均粒径は５μｍ、接着剤樹脂組成物に対する容量比は４％である。得られたサンプルについて、引張試験機による９０°剥離試験（５０ｍｍ／ｍｉｎ）により接着力を測定すると共に、デジタルマルチメータにより厚み方向の導通抵抗を測定し、結果を表１に示した。
【００６４】
実施例２
ポリビニルブチラールの代りにユニチカ株式会社製飽和共重合ポリエステル「エリーテルＵＥ３６００」にメタクリロキシ基を導入した変性ポリエステルをベース樹脂として用いた他は実施例１と同様にしてフィルムを得、基板を接着した。同様にして行った測定の結果を表１に示す。
【００６５】
参考例１
実施例１の異方性導電フィルムを表裏反転させ、リン酸系化合物含有層をＩＴＯ側とし、リン酸系化合物非含有層をＦＰＣ側として接着を行い、同様の測定を行った。その結果を表１に示す。
【００６６】
比較例１
異方性導電フィルムの全体をリン酸系化合物非含有層としたほかは実施例１と同様にして異方性導電フィルムを製造し、同様の接着を行った。同様にして行った測定結果を表１に示す。
【００６７】
比較例２
異方性導電フィルムの全体をリン酸系化合物含有層としたほかは実施例１と同様にして異方性導電フィルムを製造し、同様の接着を行った。同様にして行った測定結果を表１に示す。
【００６８】
【表１】

【００６９】
表１より、本発明の異方性導電フィルムは著しく接着性及び導通性に優れることがわかる。なお、参考例１及び比較例１は接着性が悪く、参考例１及び比較例３は導通性が悪い。
【００７０】
【発明の効果】
以上詳述した通り、本発明によれば、ＩＴＯとポリイミド等との両方に対して高い接着力を示し、しかも導通性も良好な異方性導電フィルムが提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anisotropic conductive film having conductivity only in the thickness direction, and particularly to an anisotropic conductive film excellent in adhesiveness to a resin substrate, particularly a polyimide resin substrate.
[0002]
[Prior art]
The anisotropic conductive film is formed by forming an adhesive resin composition in which conductive particles are dispersed, and conductivity is imparted in the thickness direction by applying pressure in the thickness direction. For example, the anisotropic conductive film is interposed between circuits that face each other, and pressurizes and heats between the circuits to connect the circuits through conductive particles, and adhesively fixes the circuits. Used for purposes.
[0003]
This anisotropic conductive film is different between various terminals including connecting a flexible printed circuit board (FPC) or TAB to an ITO (tin indium oxide) terminal formed on a glass substrate of a liquid crystal panel. It is used in the case of forming an isotropic conductive film, thereby bonding the terminals and electrically bonding them.
[0004]
Conventional anisotropic conductive films are generally composed of an epoxy or phenolic resin and an adhesive mainly composed of a curing agent, in which conductive particles are dispersed. Among them, adhesives are used for convenience in use. One-pack type thermosetting type is the mainstream. In addition, as an anisotropic conductive film, in order to obtain stable connection reliability even under high temperature and high humidity, the adhesion strength is enhanced by various methods. An anisotropic conductive film using a resin has low adhesive force, poor workability, and has a problem in moisture and heat resistance.
[0005]
In view of the above, the applicant of the present invention previously described an anisotropic conductive film comprising a heat or photocurable adhesive mainly composed of a polyacetalized resin obtained by acetalizing polyvinyl alcohol (Japanese Patent Laid-Open No. 10-338860). Or an anisotropic conductive film made of a heat or photocurable adhesive mainly composed of a (meth) acrylic resin obtained by polymerizing acrylic monomers and / or methacrylic monomers (Japanese Patent Laid-Open No. Hei 10- 338844).
[0006]
By the way, in recent years, the constituent material of the substrate has been changed to polyimide for the purpose of reducing the weight and thickness of the substrate.
[0007]
[Problems to be solved by the invention]
However, the conventional anisotropic conductive film cannot obtain a high adhesive force to polyimide, and its improvement is desired. The present inventor has found that the adhesion of the anisotropic conductive film to the polyimide is improved by adding the phosphoric acid compound to the anisotropic conductive film, but this phosphate compound deteriorates ITO. It has also been found that there is a possibility of causing it.
[0008]
An object of the present invention is to solve the above-mentioned conventional problems, and to provide an anisotropic conductive film that exhibits high adhesion to polyimide and does not deteriorate ITO.
[0009]
[Means for Solving the Problems]
The anisotropic conductive film of the present invention is an anisotropic conductive film formed by forming an adhesive resin composition in which conductive particles are dispersed, and the adhesive resin composition contains a phosphate compound. A phosphoric acid compound-containing layer, and a phosphate compound-free layer that does not contain the phosphoric acid compound in the adhesive resin composition; The base resin of the resin composition is a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or a modified polyacetalized resin obtained by introducing an aliphatic unsaturated group into the side chain of the polyacetalized resin, or a solvent. It is a soluble polyester unsaturated compound, and in the phosphate compound-containing layer, the amount of the phosphate compound is 0.1 to 50 parts by weight with respect to 100 parts by weight of the adhesive resin composition, The phosphate compound-containing layer is arranged only on one surface of the phosphate compound-free layer.
[0010]
As a result of intensive studies to develop an anisotropic conductive film exhibiting high adhesion to polyimide, the present inventors blend a phosphoric acid compound into the resin composition constituting the anisotropic conductive film. As a result, it was found that this adhesive force was greatly improved. In the present invention, the phosphoric acid compound-containing layer is disposed only on one surface of the phosphoric acid compound-free layer, whereby the phosphoric acid compound-containing layer is disposed on the side opposite to the ITO to adhere the substrates to each other. It is intended to be used.
[0011]
In this invention, it is preferable that the acid value of this phosphoric acid type compound is 100-800.
[0012]
Moreover, it is preferable that this phosphoric acid type compound is at least 1 sort (s) of phosphate ester, phosphite ester, and phosphate.
[0013]
In the present invention, as the base resin, a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or a modified polyacetalized resin obtained by introducing an aliphatic unsaturated group into the side chain of this polyacetalized resin Or , Solvent-soluble polyester unsaturated compounds Is used The
[0014]
The resin composition of the anisotropic conductive film of the present invention has an organic peroxide or photosensitizer of 0.1 to 10 parts by weight and a silane coupling agent of 0.01 to 100 parts by weight of the base resin. It is preferable to contain -5 weight part.
[0015]
Moreover, it is preferable that the compounding quantity of electroconductive particle is 0.1-15 volume% with respect to adhesive agent resin composition.
[0016]
In the present invention, the adhesive resin composition preferably contains 0.1 to 10 parts by weight of an organic peroxide or a photosensitizer with respect to 100 parts by weight of the base resin.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0018]
In the present invention, the base resin of the resin composition constituting the adhesive is a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or a modification obtained by introducing an aliphatic unsaturated group into the side chain of this polyacetalized resin. Polyacetalized resin or polyester unsaturated compound soluble in solvent With things is there.
[0019]
As the polyacetalized resin, those having an acetal group ratio of 30 mol% or more are preferable. If the ratio of the acetal group is less than 30 mol%, the moisture resistance may be deteriorated. Examples of the polyacetalized resin include polyvinyl formal, polyvinyl butyral and the like, and polyvinyl butyral is particularly preferable. As such a polyacetalization resin, a commercial item can be used, for example, "Denka PVB3000-1""DenkaPVB2000-L" etc. by Denki Kagaku Kogyo Co., Ltd. can be used.
[0020]
As the modified polyacetalized resin, modified polyvinyl butyral is preferable.
[0021]
The polyvinyl butyral resin is composed of a vinyl butyral unit A, a vinyl alcohol unit B, and a vinyl acetate unit C as shown in the following formula (1). The aliphatic unsaturated group may be introduced into any side chain of these units A, B and C, but those introduced into the side chain of the polyvinyl alcohol unit B are preferred. As the aliphatic unsaturated group, for example, a vinyl group, an allyl group, a methacryl group, an acrylic group, and the like are preferable.
[0022]
The introduction of the aliphatic unsaturated group into the side chain of the polyvinyl alcohol unit B is preferably carried out by acid-modifying the side-chain hydroxyl group. Examples of acids used for the acid modification include acrylic acid, methacrylic acid, stearyl. Examples thereof include acid, maleic acid, phthalic acid, and the like, and an aliphatic unsaturated bond can be introduced as shown in the following formula (2).
[0023]
[Chemical 1]

(In the formula, R represents a hydrogen atom or an alkyl group, and R ′ represents an aliphatic unsaturated group such as an alkenyl group or a group containing the same.)
[0024]
In the above formula (1), the vinyl alcohol unit B is preferably 3 to 70 mol%, more preferably 5 to 50 mol%, still more preferably 5 to 30 mol%. When the amount is more than 70 mol%, heat resistance and moisture resistance may be inferior.
[0025]
In the present invention, the adhesive resin composition is a solvent that is the main component of the adhesive (wherein, the solvent is, for example, acetone, MEK, ethyl acetate, cellosolve, dioxane, THF, benzene, cyclohexanone, Solvesso 100, etc. A polyester unsaturated compound soluble in the organic solvent. This polyester unsaturated compound is a radical reaction such as an unsaturated polyester obtained by reacting a polybasic acid and a polyhydric alcohol, and a compound in which a (meth) acryloxy group is introduced into a saturated copolymer polyester soluble in a solvent. It is a curable polyester unsaturated compound. That is, with this polyester unsaturated compound
(1) Unsaturated polyester compound
(2) Compound in which (meth) acryloxy group and / or methacryloxy group is introduced into saturated polyester
There are two types.
[0026]
Here, the saturated copolyester soluble in the solvent is mainly composed of terephthalic acid and ethylene glycol and / or 1,4-butanediol, and 5 to 50 mol% of phthalic acid and isophthalic acid in the total acid components. 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, in an amount of 5 to 50 mol% of acid components such as adipic acid, sebacic acid, dodecanoic acid and / or all alcohol components, One or more alcohol components such as 2-diethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,6-hexanediol and 1,9-nonanediol Copolymerized with
[0027]
As a method for introducing a (meth) acryloxy group into such a saturated copolymerized polyester,
(1) A method of reacting an isocyanate alkyl (meth) acrylate with a hydroxyl group of the saturated copolymerized polyester,
(2) A method by transesterification of alkyl (meth) acrylate and hydroxyl group of the saturated copolymerized polyester,
(3) A method of reacting an isocyanate alkyl (meth) acrylate by a reaction of a diisocyanate compound and a hydroxyalkyl (meth) acrylate with a hydroxyl group of the saturated copolymerized polyester.
Can be adopted.
[0028]
In the present invention, in order to improve the adhesion of such a base resin to a polyimide resin or the like, a phosphate compound is added to the base resin in the phosphate compound-containing layer. As the phosphoric acid compound, those having an acid value of 100 to 800, particularly 500 to 700 are preferable. When the acid value is 100 or less, the effect of improving the adhesive strength is low, and when it is 800 or more, the acidity is too high, and the conduction characteristics and the storage stability may be extremely deteriorated. As the phosphoric acid compound, acidic phosphate ester, phosphite ester and phosphate are preferable, and specifically, methyl acid phosphate, butyl acid phosphate, isodecyl acid phosphate, monobutyl phosphate, diphenyl phosphorochlorate. Examples thereof include date, diphenyl-2-methacryloyloxyethyl phosphate, 2-methacryloyloxyethyl acid phosphate, and phosphoric acid chloride. These phosphoric acid compounds may be used alone or in combination of two or more.
[0029]
The amount of the phosphoric acid compound is 0.1 to 50 parts by weight (phr) with respect to 100 parts by weight of the adhesive resin composition. It is. Particularly preferred is 0.3 to 4 parts by weight. If the blending amount is less than 0.1 phr, the effect of improving the adhesive strength is low, and if it exceeds 50 phr, the acidity is too high, and the conduction characteristics and storage stability may be extremely deteriorated.
[0030]
In the present invention, the side of the anisotropic conductive film to be bonded to ITO is a phosphate compound-free layer, the opposite side is a phosphate compound-containing layer, and this phosphate compound-containing layer is bonded to polyimide or the like. . Layer thickness t of phosphoric acid compound non-containing layer ₀ And layer thickness t of phosphoric acid compound-containing layer ₁ Ratio t ₀ / T ₁ Is preferably about 0.1 to 10, particularly about 0.5 to 2. The total thickness of the anisotropic conductive film is preferably about 10 to 60 μm, particularly about 15 to 40 μm.
[0031]
In the adhesive resin composition according to the present invention, for improving the adhesion of the anisotropic conductive film. In addition, You may mix | blend at least 1 sort (s) of a melamine type resin and an alkyd resin.
[0033]
Examples of the melamine resin include one or more of melamine resin, isobutylated melamine resin, butylated melamine resin such as n-butylated melamine resin, and methylated melamine resin. Such a melamine-based resin is preferably blended in an amount of 1 to 200 parts by weight, particularly 1 to 100 parts by weight, based on 100 parts by weight of the base resin.
[0034]
As the alkyd resin, either a pure alkyd resin or a modified alkyd resin may be used, but an oil-free or short oil type or medium oil type resin is preferable. Such an alkyd resin is preferably blended in an amount of 0.01 to 10 parts by weight, particularly 0.5 to 5 parts by weight, based on 100 parts by weight of the base resin.
[0035]
In this adhesive resin composition, a urea-based resin may be blended in order to prevent bubbles from being mixed into the adhesive layer and to ensure higher conductivity and adhesive strength. As the urea resin, urea resin, butylated urea resin, or the like can be used. For the same purpose, phenol resin, butylated benzoguanamine resin, epoxy resin and the like can be used.
[0036]
It is preferable that the resin for preventing air bubbles from mixing, such as urea-based resin, is 0.01 to 10 parts by weight, particularly 0.5 to 5 parts by weight with respect to 100 parts by weight of the base resin.
[0037]
In the present invention, an adhesive resin composition is used to improve or adjust the physical properties (mechanical strength, adhesiveness, optical properties, heat resistance, moisture resistance, weather resistance, crosslinking speed, etc.) of the anisotropic conductive film. It is preferable to add a reactive compound (monomer) having an acryloxy group, a methacryloxy group or an epoxy group. As this reactive compound, acrylic acid or methacrylic acid derivatives, such as esters and amides thereof, are most common, and as ester residues, in addition to alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl Group, tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 3-chloro-2-hydroxypropyl group and the like. Further, esters with polyfunctional alcohols such as ethylene glycol, triethylene glycol, polypropylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol are also used. A typical amide is diacetone acrylamide. Examples of the polyfunctional crosslinking aid include acrylic acid or methacrylic acid ester such as trimethylolpropane, pentaerythritol, and glycerin. Examples of the epoxy group-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl. Examples include ether, phenol (EO) 5 glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether. Moreover, the same effect can be acquired by alloying the polymer containing an epoxy group.
[0038]
These reactive compounds are used as one or a mixture of two or more, usually added in an amount of 0.5 to 80 parts by weight, preferably 0.5 to 70 parts by weight with respect to 100 parts by weight of the base resin. If this blending amount exceeds 80 parts by weight, workability and film forming property during preparation of the adhesive may be lowered.
[0039]
In the present invention, when the adhesive resin composition is a thermosetting type, an organic peroxide is blended as a curing agent, and this organic peroxide decomposes at a temperature of 70 ° C. or higher to generate radicals. Any material can be used as long as it has a decomposition temperature of 50 ° C. or more, with a half-life of 10 hours, film formation temperature, preparation conditions, curing (bonding) temperature, heat resistance of adherend, storage It is selected in consideration of stability.
[0040]
Examples of usable organic peroxides include 2,5-dimethylhexane, 2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne 3, and di- t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, α, α′-bis (t-butylperoxy) Isopropyl) benzene, n-butyl-4,4′-bis (t-butylperoxy) valerate, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy)- 3,3,5-trimethylcyclohexane, t-butyl peroxybenzoate, benzoyl peroxide, t-butyl peroxyacetate, methyl ethyl ketone Peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, butyl hydroperoxide, p-menthane hydroperoxide, p-chlorobenzoyl peroxide, hydroxyheptyl peroxide, chlorohexanone peroxide, octanoyl Peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxy octoate, succinic acid peroxide, acetyl peroxide, t-butyl peroxy (2-ethylhexanoate), m-toluoyl peroxide, t -Butyl peroxyisobutyrate, 2,4-dichlorobenzoyl peroxide, etc. are mentioned. These organic peroxides may be used alone or in combination of two or more.
[0041]
Such an organic peroxide is preferably blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the base resin.
[0042]
In the present invention, when the adhesive resin composition is a photocurable type, a photosensitizer that generates radicals by light is blended. As the photosensitizer (photopolymerization initiator), radical light is used. A polymerization initiator is preferably used. Among radical photopolymerization initiators, benzophenone, methyl o-benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, isopropylthioxanthone, diethylthioxanthone, ethyl 4- (diethylamino) benzoate and the like as hydrogen abstraction type initiators. It can be used. Among radical photopolymerization initiators, benzoin ether, benzoylpropyl ether, benzyldimethyl ketal as an intramolecular cleavage type initiator, and 2-hydroxy-2-methyl-1-phenylpropane-1 as an α-hydroxyalkylphenone type -One, 1-hydroxycyclohexyl phenyl ketone, alkylphenylglyoxylate, diethoxyacetophenone, also as α-aminoalkylphenone type, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopro Panone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 and acylphosphine oxide are used. These photosensitizers may be used alone or in combination of two or more.
[0043]
Such a photosensitizer is preferably blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the base resin.
[0044]
It is preferable to add a silane coupling agent as an adhesion promoter to the adhesive resin composition. As silane coupling agents, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ -1 type, or 2 or more types of mixtures, such as aminopropyl trimethoxysilane, is used.
[0045]
The amount of these silane coupling agents added is usually 0.01 to 5 parts by weight per 100 parts by weight of the base resin.
[0046]
In addition, a hydrocarbon resin can be added to the adhesive resin composition for the purpose of improving processability and bonding property. In this case, the added hydrocarbon resin may be either a natural resin type or a synthetic resin type. In the natural resin system, rosin, rosin derivatives, and terpene resins are preferably used. For rosin, gum-based resins, tall oil-based resins, and wood-based resins can be used. As the rosin derivative, rosin obtained by hydrogenation, heterogeneity, polymerization, esterification, or metal chloride can be used. As the terpene resin, a terpene phenol resin can be used in addition to a terpene resin such as α-pinene and β-pinene. Moreover, you may use danmaru, koval, and shellac as another natural resin. On the other hand, in the synthetic resin system, petroleum resin, phenol resin, and xylene resin are preferably used. As the petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, hydrogenated petroleum resin, pure monomer petroleum resin, and coumarone indene resin can be used. As the phenol resin, an alkyl phenol resin or a modified phenol resin can be used. As the xylene-based resin, a xylene resin or a modified xylene resin can be used.
[0047]
Although the addition amount of such a hydrocarbon resin is appropriately selected, it is preferably 1 to 200 parts by weight, more preferably 5 to 150 parts by weight with respect to 100 parts by weight of the base resin.
[0048]
In addition to the above additives, an anti-aging agent, an ultraviolet absorber, a dye, a processing aid and the like may be used in the adhesive resin composition according to the present invention as long as the object of the present invention is not impaired.
[0049]
Any conductive particles may be used as long as they are electrically good conductors, and various particles can be used. For example, a metal or alloy powder such as copper, silver or nickel, a resin or ceramic powder coated with such a metal or alloy, and the like can be used. The shape is not particularly limited, and any shape such as a flake shape, a dendritic shape, a granular shape, or a pellet shape can be taken.
[0050]
The conductive particles have an elastic modulus of 1.0 × 10 ⁷ ~ 1.0 × 10 ¹⁰ What is Pa is preferable. That is, when an anisotropic conductive film is used to connect an adherend such as a liquid crystal film using a plastic film as a base material, cracks may occur in the adherend if conductive particles having a high elastic modulus are used. It is recommended to use conductive particles in the above elastic modulus range because there is a possibility that stable conduction performance may not be obtained due to spring breakage due to breakage of the particles or recovery of elastic deformation of the particles after pressure bonding. This prevents destruction of the adherend, suppresses the occurrence of springback due to recovery of elastic deformation of the particles after pressure bonding, and makes it possible to increase the contact area of the conductive particles for more stable reliability. High conduction performance can be obtained. The elastic modulus is 1.0 × 10 ⁷ If it is less than Pa, the particles themselves may be damaged, and the conduction characteristics may be lowered. ¹⁰ If it is larger than Pa, there is a risk of occurrence of springback. As such conductive particles, those obtained by coating the surfaces of the plastic particles having the above-described elastic modulus with the aforementioned metal or alloy are preferably used.
[0051]
In this invention, it is preferable that the compounding quantity of such electroconductive particle is 0.1-15 volume% with respect to the said base resin, and the average particle diameter of this electroconductive particle is 0.1-100 micrometers. It is preferable that Thus, by prescribing the blending amount and the particle size, the conductive particles are condensed between adjacent circuits, and it becomes difficult to short-circuit, and good conductivity can be obtained.
[0052]
The anisotropic conductive film of the present invention is obtained by dispersing such conductive particles in an adhesive resin composition. The adhesive resin composition containing the conductive particles preferably has a melt index (MFR) of 1 to 3000, particularly 1 to 1000, particularly 1 to 800, and a fluidity at 70 ° C. of 10 ⁵ Therefore, it is desirable to select a formulation so that such MFR and fluidity can be obtained.
[0053]
The anisotropic conductive film of the present invention is prepared by uniformly mixing the adhesive resin composition and conductive particles in a predetermined composition and kneading them with an extruder, roll, etc., and then calender roll, T-die extrusion, inflation. It can be manufactured by forming a phosphoric acid compound non-containing layer and a phosphoric acid compound containing layer by laminating them into a predetermined shape by a film forming method such as May be. The non-containing layer and the containing layer of the phosphoric acid compound can also be formed by dissolving or dispersing the adhesive resin composition and conductive particles in a solvent, applying the solution to the surface of the separator, and then evaporating the solvent. Can be membrane. In this case, after forming one layer, the other layer may be formed thereon by the above-described solvent vapor deposition process. In the film formation, embossing may be performed for the purpose of preventing blocking and facilitating pressure bonding with the adherend.
[0054]
In order to adhere the adherends to each other with the anisotropic conductive film thus obtained, for example, a bonding method using a hot press, an extruder, a direct lamination method using a calendar, a thermocompression bonding method using a film laminator, etc. Various techniques can be used. At this time, as described above, the phosphoric acid compound-free layer is the ITO side.
[0055]
As the curing conditions in the anisotropic conductive film of the present invention, in the case of thermosetting, depending on the type of organic peroxide used, it is usually 70 to 170 ° C., preferably 70 to 150 ° C., usually 10 seconds to 120 minutes, preferably 20 seconds to 60 minutes.
[0056]
In the case of photocuring using a photosensitizer, many light sources that emit light in the ultraviolet to visible region can be used as a light source, such as ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, Mercury halogen lamp, A carbon arc lamp, an incandescent lamp, a laser beam, etc. are mentioned. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but it is about several tens of seconds to several tens of minutes.
[0057]
In order to accelerate curing, the laminate may be preheated to 40 to 120 ° C. and irradiated with ultraviolet rays.
[0058]
At the time of bonding, it is preferable to apply a pressure of about 1 to 4 MPa, particularly about 2 to 3 MPa in the bonding direction.
[0059]
The anisotropic conductive film of the present invention has a conductivity of 10Ω or less, particularly 5Ω or less in the film thickness direction, and a resistance in the plane direction of 10 ⁶ Ω or more, especially 10 ⁹ It is preferable that it is Ω or more.
[0060]
The anisotropic conductive film of the present invention is suitable for connecting, for example, FPC or TAB to an ITO terminal on a glass substrate of a liquid crystal panel, but can also be used for other applications. According to the above, a crosslinked structure is formed at the time of curing, and high adhesiveness, excellent durability, and heat resistance are obtained.
[0061]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to a following example, unless the summary is exceeded.
[0062]
Example 1
A toluene 25 wt% solution of polyvinyl butyral (“Denka PVB3000-1” manufactured by Denki Kagaku Kogyo Co., Ltd.) was prepared, and the components shown in “FPC side” of Table 1 with respect to 100 parts by weight of polyvinyl butyral in the amounts shown in Table 1. After mixing, this was coated on poly (ethylene terephthalate) as a separator by a bar coater. After evaporating the toluene, a solution having the same formulation was applied thereon except that it did not contain a phosphoric acid compound to obtain a film having a width of 5 mm and a thickness of 15 μm. The thickness of the phosphoric acid compound-containing layer is 8 μm, and the thickness of the phosphoric acid compound-free layer is 7 μm.
[0063]
The film is applied to a PET resin substrate with SiO. _X For adhesion between a substrate with ITO terminals formed through a film and a substrate (FPC) patterned with a copper foil on a polyimide substrate, the separator is peeled off and positioned with a monitor, and the phosphate compound-containing layer is placed on the FPC side. Then, the phosphoric acid compound-free layer was the ITO side, and thermocompression bonded at 130 ° C. for 20 seconds at 3 MPa. As shown in Table 1, monobutyl phosphate (acid value 670) is used as the phosphoric acid compound in this example. The average particle diameter of the conductive particles is 5 μm, and the volume ratio to the adhesive resin composition is 4%. About the obtained sample, while measuring adhesive force by the 90 degree peeling test (50 mm / min) with a tensile tester, the conduction resistance of the thickness direction was measured with the digital multimeter, and the result was shown in Table 1.
[0064]
Example 2
A film was obtained in the same manner as in Example 1 except that a modified polyester having a methacryloxy group introduced into a saturated copolymer polyester “Elitel UE3600” manufactured by Unitika Ltd. was used as a base resin instead of polyvinyl butyral, and a substrate was adhered thereto. The results of measurements performed in the same manner are shown in Table 1.
[0065]
Reference example 1
The anisotropic conductive film of Example 1 was turned upside down, the phosphoric acid compound-containing layer was bonded to the ITO side, and the phosphoric acid compound non-containing layer was bonded to the FPC side, and the same measurement was performed. The results are shown in Table 1.
[0066]
Comparative Example 1
An anisotropic conductive film was produced in the same manner as in Example 1 except that the entire anisotropic conductive film was a phosphoric acid compound-free layer, and the same adhesion was performed. The measurement results obtained in the same manner are shown in Table 1.
[0067]
Comparative Example 2
An anisotropic conductive film was produced in the same manner as in Example 1 except that the entire anisotropic conductive film was a phosphoric acid compound-containing layer, and the same adhesion was performed. The measurement results obtained in the same manner are shown in Table 1.
[0068]
[Table 1]

[0069]
Table 1 shows that the anisotropic conductive film of this invention is remarkably excellent in adhesiveness and electroconductivity. Note that Reference Example 1 and Comparative Example 1 have poor adhesion, and Reference Example 1 and Comparative Example 3 have poor conductivity.
[0070]
【The invention's effect】
As described above in detail, according to the present invention, an anisotropic conductive film that exhibits high adhesion to both ITO and polyimide, and also has good electrical conductivity is provided.

Claims (6)

In an anisotropic conductive film formed by forming an adhesive resin composition in which conductive particles are dispersed,
A phosphate compound-containing layer in which a phosphate compound is contained in the adhesive resin composition;
A phosphate compound-free layer that does not contain the phosphate compound in the adhesive resin composition;
The base resin of the resin composition is a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or a modified polyacetalized resin obtained by introducing an aliphatic unsaturated group into the side chain of the polyacetalized resin, or a solvent. A soluble polyester unsaturated compound,
In the phosphoric acid compound-containing layer, the amount of the phosphoric acid compound is 0.1 to 50 parts by weight with respect to 100 parts by weight of the adhesive resin composition,
An anisotropic conductive film, wherein the phosphate compound-containing layer is disposed only on one surface of the phosphate compound-free layer.   The anisotropic conductive film according to claim 1, wherein the acid value of the phosphoric acid compound is 100 to 800.   3. The anisotropic conductive film according to claim 2, wherein the phosphoric acid compound is at least one of a phosphoric ester, a phosphite, and a phosphate.   The phosphoric acid compound according to claim 2 or 3, wherein the phosphoric acid compound is methyl acid phosphate, butyl acid phosphate, isodecyl acid phosphate, monobutyl phosphate, diphenyl phosphorochloridate, diphenyl-2-methacryloyloxyethyl phosphate, 2-methacryloyloxy An anisotropic conductive film characterized by being one or more of ethyl acid phosphate and phosphoric acid chloride. Anisotropic conductive film, wherein in any one of claims 1 to 4, the blending amount of the conductive particles is 0.1 to 15% by volume based on the adhesive resin composition. In any one of claims 1 to 5, and characterized in that said adhesive resin composition contains 0.1 to 10 parts by weight of an organic peroxide or photosensitizer relative to 100 parts by weight of the base resin An anisotropic conductive film.