JP2004179139A - Conductive particles and conductive adhesive material containing it and paint for forming transparent conductive film, and transparent conductive film as well as display device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide conductive particles, in which environmental resistance such as salt water resistance, acid resistance, oxidation resistance, ultraviolet resistance or the like has been improved, a conductive adhesive material containing these conductive particles, a coating for forming a transparent conductive film, the transparent conductive film obtained by applying this coating for forming the transparent conductive film, and a display device in which this transparent conductive film is formed on a display face. <P>SOLUTION: As for these conductive particles, on the surface of metal particles 1, a covered layer 2 composed of oxides is formed. These conductive particles are not only superior in transparency, conductivity, antistaticity, and electromagnetic wave shielding property by having the covered layer composed of oxides formed on the surface of the metal particle, but also superior in the environment resistance improved such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. <P>COPYRIGHT: (C)2004,JPO

Description

の範囲が好ましい範囲である。
【００２８】
ここで、第２の金属粒子４の量を２〜３０重量％と限定した理由は、その量が２重量％より少ない場合には、被覆層２の内部、表面のいずれか一方または双方の一部に存在する第２の金属粒子４と、中心核となる金属粒子１との導通性が悪く、良好な導電性が得られ難くなるからであり、また、３０重量％より多い場合には、これ以上加えても導電性、耐酸化性・耐化学性等のさらなる改善効果が期待できないからである。
【００２９】
本実施形態の導電性粒子では、上記の様な構造をとることにより、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性に優れたものとなる。また、酸化物からなる被覆層２が第２の金属粒子４を含有した場合、この導電性粒子の導電性は、中心核となる金属粒子１と、被覆層２の内部、表面のいずれか一方または双方の一部に存在する第２の金属粒子４との間に電気が流れることにより得られるものであるが、導電性への寄与は金属粒子１の方が遙かに大きいので、この時に得られる導電性は、主として金属粒子１が担うことになる。
【００３０】
また、被覆層２は、金属粒子１と、酸性ガスやアルカリ性ガスといった腐食性ガスやエレクトロマイグレーションを誘因する水蒸気、あるいは金属を酸化させてしまう酸素との接触を抑制する。
この被覆層２の内部、表面のいずれか一方または双方の一部に存在する第２の金属粒子４は、酸化物層３中に存在する分子サイズ〜数１０ｎｍレベルの空隙を塞ぐことで、酸化性ガス、腐食性ガスあるいは水蒸気と、中心核となる金属粒子１との接触をさらに抑制させると同時に、この金属粒子１との導通を確保している。
【００３１】
また、図３に示すように、被覆層５を構成する酸化物層３中に存在する空隙が、酸化物層３の表面から金属粒子１の表面まで通じている場合、第２の金属粒子４は、この酸化物層３の表面から金属粒子１の表面まで通して析出していることが好ましい。第２の金属粒子４がこの様に析出することにより、酸化性ガス、酸性ガス、アルカリ性ガスといった腐食性ガス、あるいはエレクトロマイグレーションを誘因する水蒸気等といったガスと、中心核となる金属粒子１との接触をさらに抑制することができる。さらに、金属粒子１と第２の金属粒子４とが接触していることにより、優れた導電性が得られる。
【００３２】
次いで、本実施形態の導電性粒子の製造方法について説明する。
中心核となる金属粒子１の表面に、酸化物からなる被覆層２を形成するには、金属粒子あるいはコロイド状の金属粒子を、アミノシラン、メルカプトシラン、グリシドキシシラン、メタクリロキシシラン等のシランカップリング剤を用いて表面修飾し、その後、珪酸ソーダ等の珪酸アルカリ溶液あるいは金属アルコキシド溶液中に浸漬し、金属粒子１の表面に被覆層２を形成する。
【００３３】
上記のシランカップリング剤としては、
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―アミノプロピルメトキシシラン、
Ｎ−（β―アミノエチル）−γ―アミノプロピルメチルジメトキシシラン、
γ―メルカプト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メトキシシラン、
γ―グリシドキシプロピルメチルジメトキシシラン、
γ―メタクリロキシプロピルトリメトキシシラン、
γ―メタクリロキシプロピルジメトキシシラン等を例示することができる。
【００３４】
上記の金属アルコキシドとしては、シリコンメトキシド、シリコンエトキシド、シリコンプロポキシド等のシリコンアルコキシド、アルミニウムプロポキシド、アルミニウムブトキシド等のアルミニウムアルコキシド、チタンプロポキシド、チタンブトキシド等のチタンアルコキシド、ジルコニウムプロポキシド、ジルコニウムブトキシド等のジルコニウムアルコキシド、スズプロポキシド、スズブトキシド等のスズアルコキシド等を例示することができる。
【００３５】
上記のシランカップリング剤を用いて金属粒子１の表面を修飾する場合、中心核となる金属粒子１の表面に在るカップリング剤のシラノール基（−ＳｉＯＨ）上で、珪酸アルカリや金属アルコキシドの加水分解反応や縮重合反応が行われることにより、金属粒子１の表面に酸化物からなる被覆層２が形成される。この被覆層２の厚みは、被覆層２を形成する際の溶液の温度及び浸漬の時間を制御することにより、所望の厚みに制御することが可能である。
【００３６】
さらに、被覆層２の内部、表面のいずれか一方または双方に金属粒子４を析出させるには、上記の被覆層が形成された金属粒子を、中心核となる金属粒子よりもイオン化傾向の小さい、塩酸塩、硝酸塩、酢酸塩、亜硫酸塩等の金属塩溶液、あるいは乳酸塩、クエン酸塩等の有機酸金属塩溶液に浸漬、または接触させ、被覆層２の内部、表面のいずれか一方または双方に第２の金属粒子４を析出させる。
【００３７】
この場合、中心核となる金属粒子１のイオン化傾向と、金属塩中の金属イオンのイオン化傾向の差により、金属粒子１の成分である金属は酸化されて金属塩溶液中へ金属イオンとして溶出し、同時に金属塩溶液中の金属イオンは還元されて金属粒子となって被覆層２の内部、表面のいずれか一方または双方に析出する。例えば、金属粒子１としてＡｇ粒子を用いる場合、用いる金属塩の金属種としては、Ａｕ、Ｐｔ、Ｐｄ、Ｏｓ、Ｉｒ、Ｒｕ、Ｒｅ、Ｒｈ等を用いることができ、特に、Ａｕ、Ｐｔ、Ｐｄ、Ｒｕが好適である。
【００３８】
これらの金属塩の金属種は、複数の金属種を共存させた金属塩溶液を用いても上記と同様の析出反応が生じる。したがって、複数の金属種を共存させた金属塩溶液を用いることにより、被覆層２の内部、表面のいずれか一方または双方に、中心核となる金属粒子１とは異なる合金粒子または複数の種類の金属粒子を含む導電性粒子を作製することが可能である。
【００３９】
なお、上記の金属塩溶液の替わりに、複数の金属種を共存させた乳酸塩、クエン酸塩等の有機酸金属塩溶液を用いても上記と同様の析出反応が生じる。
また、析出させる金属量の制御は、上記の金属塩溶液あるいは有機酸金属塩溶液中に存在する金属イオン量を制御することにより可能になる。
以上により、本実施形態の導電性粒子を作製することができる。
【００４０】
この様にして得られた導電性粒子は、塩水、酸性または酸化性の液体またはガス等の劣化因子と長期間接触させても電気伝導度に変化は見られず、したがって、本実施形態の導電性粒子を用いることにより、得られる透明導電膜の帯電防止性あるいは電磁波遮蔽性は、長期間に亘って維持することができる。また、これらの導電性粒子の電気伝導度は、いずれも１０^−５Ωｃｍ以下であり、これらの導電性粒子を含有する透明導電膜を成膜した場合の表面抵抗は１０^−１〜１０^３Ω／□であるから、実用的に十分な電磁波遮蔽性能を得ることができる。
【００４１】
本実施形態の導電性粒子は、中心核となる金属粒子１の表面に酸化物からなる被覆層２が形成されているので、この導電性粒子を用いて形成された導電層は、膜強度が著しく向上し、スクラッチ強度が向上する。また、導電層の上層または下層（いずれか一方の主面）または上層および下層（双方の主面）に、この導電層の屈折率とは異なる屈折率を有する透明層を１層以上設けた場合には、通常、透明層として用いられるシリカ系バインダー成分との濡れ性が良く、双方の層の密着性が向上するという利点もあり、スクラッチ強度をいっそう改善することができる。
【００４２】
「コロイド状分散液」
上記の導電性粒子に電気透析等の通常の洗浄方法を施すことで、コロイド状の分散液を得ることができる。特に、本実施形態の導電性粒子を用いたコロイド状分散液は、中心核となる金属粒子の表面に形成された酸化物からなる被覆層の電気二重層による分散系であるから、従来の金属コロイドに比べて極めて安定性が高く、しかも導電性粒子の濃度が高い分散液を得ることができる。
【００４３】
「透明導電膜形成用塗料」
上記のコロイド状分散液を溶剤に添加することで、本実施形態の透明導電膜形成用塗料を得ることができる。
溶剤としては、例えば、水や有機溶媒が挙げられ、有機溶媒としては、メタノール、エタノール、プロパノール、ブタノール等のアルコール類、β−オキシエチルメチルエーテル（メチルセロソルブ）、β−オキシエチルエーテル（エチルセロソルブ）、ブチル−β−オキシエチルエーテル（ブチルセロソルブ）等のエーテル類、フェノール類、エステル類、ケトン類、グリコール類、芳香族化合物等が挙げられる。
【００４４】
この透明導電膜形成用塗料は、上述した導電性粒子の他に、透明導電膜の透過光の色調調整のために、着色剤として、染料や有機顔料、あるいは化学的安定性の高い金属微粒子を微量含んでいてもよい。
着色材は、透明導電膜を構成するいずれの層に添加してもよいが、例えば、透明導電層に添加する場合は、その添加量は金属粒子の含有量に対して２０重量％以下、特に１０重量％以下とすることが好ましい。
その理由は、添加量が２０重量％を越えると、導電性の低下および膜強度の劣化が生じ、電磁波遮蔽効果に支障をきたすことになるからである。
【００４５】
上記の着色材としては、例えば、モノアゾピグメント、キナクリドン、アイアンオキサイド・エロー、ジスアゾピグメント、フタロシアニングリーン、フタロシアニンブルー、シアニンブルー、フラバンスロンエロー、ジアンスラキノリルレッド、インダンスロンブルー、チオインジゴボルドー、ペリレンオレンジ、ペリレンスカーレット、ペリレンレッド１７８、ペリリレンマルーン、ジオキサジンバイオレット、イソインドリンエロー、ニッケルニトロソエロー、マダーレーキ、銅アゾメチンエロー、アニリンブラック、アルカリブルー等の有機顔料が好適に用いられる。
【００４６】
また、亜鉛華、酸化チタン、弁柄、酸化クロム、鉄黒、チタンエロ−、コバルトブルー、セルリアンブルー、コバルトグリーン、アルミナホワイト、ビリジアン、カドミウムエロー、カドミウムレッド、朱、リトポン、黄鉛、モリブデートオレンジ、クロム酸亜鉛、硫酸カルシウム、硫酸バリウム、炭酸カルシウム、鉛白、群青、マンガンバイオレット、エメラルドグリーン、紺青、カーボンブラックなどの無機顔料も好適に用いられる。
【００４７】
また、アゾ染料、アントラキノン染料、インジゴイド染料、フタロシアニン染料、カルボニウム染料、キノンイミン染料、メチン染料、キノリン染料、ニトロ染料、ニトロソ染料、ベンゾキノン染料、ナフトキノン染料、ナフタルイミド染料、ペリノン染料などの各種染料も好適に用いられる。
これらの着色材は、単独で、または２種以上を組み合わせて用いることができる。
【００４８】
また、この透明導電膜形成用塗料は、上述した各種成分の他に、膜強度や導電性の向上を目的として、必要なら他の成分、例えば、珪素（Ｓｉ）、アルミニウム（Ａｌ）、ジルコニウム（Ｚｒ）、セリウム（Ｃｅ）、チタン（Ｔｉ）、イットリウム（Ｙ）、亜鉛（Ｚｎ）、マグネシウム（Ｍｇ）、インジウム（Ｉｎ）、錫（Ｓｎ）、アンチモン（Ｓｂ）、ガリウム（Ｇａ）等の酸化物、または複合酸化物、あるいは窒化物等を含有することとしてもよく、特に、インジウム（Ｉｎ）や錫（Ｓｎ）の酸化物、複合酸化物、または窒化物を主成分とする無機物の微粒子等を含有することとしてもよい。
【００４９】
また、ポリエステル樹脂、アクリル樹脂、エポキシ樹脂、メラミン樹脂、ウレタン樹脂、ブチラール樹脂、紫外線硬化樹脂などの有機系合成樹脂、珪素、チタン、ジルコニウムなどの金属アルコキシドの加水分解物、またはシリコーンモノマー、シリコーンオリゴマーなどの有機・無機系バインダー成分等を含有することとしてもよい。
また、珪素を含んだバインダーとしての加水分解重縮合性有機珪素化合物としては、下記の式（１）で表されるアルコキシシランを挙げることができる。
Ｒ_ａＳｉ（ＯＲ’）_４−ａ ……（１）
（式中、Ｒは、ビニル基、アリール基、アクリル基、炭素原子数１〜８のアルキル基、水素原子またはハロゲン原子であり、Ｒ’は、ビニル基、アリール基、アクリル基、炭素原子数１〜８のアルキル基、−Ｃ_２Ｈ_４Ｏ_ｎＨ_２ｎ＋１（ｎ＝１〜４）、または水素原子であり、ａは０または１〜３の整数である）
【００５０】
「透明導電膜」
上記の透明導電膜形成用塗料を、例えば、ガラス基板、耐熱性透明樹脂、ガラス板等の基材の表面に塗布することにより、本実施形態の透明導電膜を得ることができる。
塗布方法としては、スピンコート法、スプレーコート法、デイップコート法、ロールコート法、バーコート法、グラビア印刷法等、公知の塗布技術を用いることができる。
これらのうち、スピンコート法、スプレーコート法、デイップコート法の各塗布方法は、短時間で均一な厚みの膜を形成することができるので、特に好ましい塗布方法である。
【００５１】
塗布後、塗布膜を乾燥し、必要に応じて焼き付けすれば、基材の表面に透明導電層を形成することができる。
塗布に際しては、形成された後の透明導電層の膜厚が、５ｎｍ〜１００ｎｍとなるような塗布量とすることが好ましい。さらには、形成された後の透明導電層の膜厚は１０ｎｍ〜５０ｎｍとすることが好ましい。
【００５２】
その理由は、膜厚が５ｎｍ未満では、十分な電磁波遮蔽効果が得難くなるばかりでなく、外観ムラになる等により均一な膜形成が困難となるからであり、一方、膜厚が１００ｎｍを越えると、導電性は問題はないが、透明導電層の光透過性が著しく低下してしまうために、実用的な透明性を得ることができなくなるからである。ここで、実用的な透明性とは、全光線透過率が４０％程度以上をいう。
【００５３】
図４は、本実施形態の透明導電膜を示す断面図であり、図において、符号１１は基材である透明なガラス基板、１２はガラス基板１１上に本実施形態の透明導電膜形成用塗料を塗布して形成された透明導電層であり、この透明導電層１２により本実施形態の透明導電膜が構成されている。
【００５４】
この透明導電層１２は、中心核となる金属粒子１の表面に耐環境性に優れた酸化物あるいは金属を含む酸化物からなる被覆層２が形成された導電性粒子を含有したものであるから、膜強度が著しく向上し、スクラッチ強度が向上する。
また、金属粒子１の表面に酸化物あるいは金属を含む酸化物からなる被覆層２が形成されているので、ハロゲン、酸性、酸化性、紫外線などの雰囲気に対して耐性があり、これらの雰囲気に長期間暴露されることがあっても、金属粒子の変質に由来する導電性の低下、変色、膜強度の低下等が生じる虞がない。
さらに、金属粒子１の表面に酸化物あるいは金属を含む酸化物からなる被覆層２が形成されているので、基材との密着性に優れたものとなる。
【００５５】
本実施形態の透明導電膜は、例えば、プラズマディスプレイパネル（ＰＤＰ）、液晶ディスプレイ（ＬＣＤ）、エレクトロルミネッセンス（ＥＬ）ディスプレイ、タッチパネル、陰極線管（ＣＲＴ）等、各種表示装置の表示パネルの表示面に適用することができる。
また、建築物等の窓ガラス、自動車のフロントガラス、自動車のメーターパネル、電子レンジの覗き窓等の各種窓材等にも適用することができる。
【００５６】
上記の表示装置や各種窓材によれば、海上輸送時の海水やオペレーターの汗等からもたらされる食塩分等のハロゲン塩や、温泉地などにおける硫化水素ガス、さらに大気中のＳＯ_ｘガス、酸性雨等の酸性液体や酸性ガス、紫外線等により発生するオゾン等の酸化性ガス等に対する耐性が高く、これらの劣化因子を含む環境下に置かれても、長期間に亘って電磁波遮蔽性、反射防止性、色相、膜強度等の初期性能を維持することができる。
【００５７】
本実施形態の透明導電膜では、膜の耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性が著しく向上する。
また、この透明導電膜とガラス等の基材との密着性が向上するので、使用時においても、剥離、傷等の不具合が生じるおそれがない。
また、上記の表示装置では、その表示面に本実施形態の透明導電膜を形成したことにより、表示面における耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性が著しく向上する。
また、この表示面と透明導電膜との密着性が向上するので、使用時においても、剥離、傷等の不具合が生じるおそれがなく、表示面における視認性、信頼性等が向上する。
【００５８】
「低反射透明導電膜」
本実施形態の低反射透明導電膜について説明する。
この低反射透明導電膜は、上記の透明導電層の上層または下層（いずれか一方の主面）または上層および下層（双方の主面）に、この透明導電層の屈折率とは異なる屈折率を有する透明な反射防止層が１層以上形成される。この反射防止層は、膜の界面における外光反射を干渉効果により除去または低減するために用いられるものである。
【００５９】
図５は、本実施形態の低反射透明導電膜を示す断面図であり、透明導電層１２の上層に、この透明導電層１２の屈折率とは異なる屈折率を有する透明な反射防止層２１が形成され、この反射防止層２１と透明導電層１２により低反射透明導電膜２２が構成されている。
【００６０】
低反射透明導電膜２２の層構成は、上記の構成に限定されるものではなく、例えば、図６に示すように、反射防止層２１を透明導電層１２の下層に形成した構成の低反射透明導電膜３１としてもよい。さらに、図７に示すように、透明導電層１２を挟むように、反射防止層２１を上層及び下層に形成した構成の低反射透明導電膜４１としてもよい。また、反射防止層２１は、１層であってもよく、２層以上であってもよい。
【００６１】
この反射防止層２１の屈折率は１．６０以下が望ましい。反射防止層２１は、単に外光の写り込みを防止し、表示装置の視認性の向上を図るのみならず、低反射透明導電膜２２、４１を外力から保護する効果も期待されるため、実用上十分な機械的強度を有することが必要である。
【００６２】
この反射防止層２１を形成する塗布剤としては、例えば、ポリエステル樹脂、アクリル樹脂、エポキシ樹脂、ブチラール樹脂等の熱可塑性樹脂、熱硬化性樹脂、または光・電子線硬化性樹脂、ケイ素、アルミニウム、ジルコニウム、チタン等の金属アルコキシドの加水分解物、シリコーンモノマーまたはシリコーンオリゴマー等から選択された１種あるいは２種以上の成分を含む塗布液を挙げることができる。上記の成分は単独で、または混合して用いることができる。
【００６３】
反射防止層２１の形成は、透明導電層１２の形成と同様に、上記の１種あるいは２種以上の成分を含む塗布液、すなわち反射防止塗料を所定の面に均一に塗布して成膜する方法により行うことができる。塗布法としては、スピンコート法、ロールコート法、スプレーコート法、デイップコート法、バーコート法、グラビア印刷法等が好適に用いられる。
塗布後は、塗布膜を乾燥し、好ましくは焼き付けまたは光・電子線照射することによって強固な膜が形成される。
【００６４】
本実施形態の低反射透明導電膜２２、３１、４１は、上述した透明導電膜と同様、例えば、プラズマディスプレイパネル（ＰＤＰ）、液晶ディスプレイ（ＬＣＤ）、エレクトロルミネッセンス（ＥＬ）ディスプレイ、タッチパネル、陰極線管（ＣＲＴ）等、各種表示装置の表示パネルの表示面に適用することができる。
また、建築物等の窓ガラス、自動車のフロントガラス、自動車のメーターパネル、電子レンジの覗き窓等の各種窓材等にも適用することができる。
【００６５】
「表示装置」
図８は、本実施形態の表示装置の表示面を示す断面図であり、プラズマディスプレイパネル（ＰＤＰ）の表示面の例である。このＰＤＰの表示面は、透明なガラス基板からなる表示パネル５１の前面に上記の低反射透明導電膜２２が形成された構成である。
【００６６】
この低反射透明導電膜２２は、透明導電層１２が本実施形態の導電性粒子を含んでいるので、電磁波遮蔽性を発現するのに十分な導電性を有している。また、透明導電層１２は、表示装置の透過像のコントラスト調整のために、その厚みが１００ｎｍ以下の範囲で透過率の調整が行われる。また、この低反射透明導電膜２２は、透明導電層１２の屈折率とは異なる屈折率を有する反射防止層２１が上層に形成されているので、外光反射が防止される。
【００６７】
また、この低反射透明導電膜２２は、その透明導電層１２に含まれる導電性粒子が、本実施形態の導電性粒子であるから、ハロゲン、酸性、酸化性、紫外線などの雰囲気に対して耐性を有するものとなり、これらの雰囲気に長期間暴露されることがあっても、導電性粒子の変質に由来する導電性の低下、変色、膜強度の低下などを起こす虞がない。さらに、透明導電層１２を構成する導電性粒子は、金属粒子１の表面に酸化物からなる被覆層２が形成されているので、基材である表示パネル５１との密着力に優れている。
【００６８】
本実施形態では、表示パネル５１の前面に低反射透明導電膜２２が形成された表示装置を例としたが、この低反射透明導電膜２２の替わりに低反射透明導電膜３１、４１を形成した構成としてもよい。
【００６９】
本実施形態の表示装置によれば、表示パネル５１の前面に低反射透明導電膜２２を形成したので、この低反射透明導電膜２２により表示装置から放射される電磁波を遮蔽することができ、各種の電磁波障害を防止することができる。
また、この低反射透明導電膜２２は光透過性に優れているので、画像が明るくなる。また、外光の写り込みが低減されるので、表示面における視認性が改善される。
また、反射防止層２１は、透明導電層１２との濡れ性が良いので、反射防止層２１と透明導電層１２の双方の層の密着性を向上させることができ、スクラッチ強度をいっそう改善することができる。
【００７０】
また、上記の透明導電膜を形成した場合と同様、海上輸送時の海水やオペレーターの汗等からもたらされる食塩分等のハロゲン塩や、温泉地などにおける硫化水素ガス、さらに大気中のＳＯ_ｘガス、酸性雨等の酸性液体や酸性ガス、紫外線等により発生するオゾン等の酸化性ガス等に対する耐性が高く、これらの劣化因子を含む環境下に置かれても、長期間に亘って電磁波遮蔽性、反射防止性、色相、膜強度等の初期性能を維持することができる。
【００７１】
この表示パネル５１に形成した低反射透明導電膜２２、３１、４１は、建築物等の窓ガラス、自動車のフロントガラス、自動車のメーターパネル、電子レンジの覗き窓等の各種窓材等に適用することができる。
これら各種窓材においても、上述した透明導電膜を形成した場合と同様、海上輸送時の海水やオペレーターの汗等からもたらされる食塩分等のハロゲン塩や、温泉地などにおける硫化水素ガス、さらに大気中のＳＯ_Ｘガス、酸性雨等の酸性液体や酸性ガス、紫外線等により発生するオゾン等の酸化性ガス等に対する耐性が高く、これらの劣化因子を含む環境下に置かれても、長期間に亘って電磁波遮蔽性、反射防止性、色相、膜強度等の初期性能を維持することができる。
【００７２】
「導電性粒子の具体例」
以下、本実施形態の導電性粒子の具体例として、被覆層の成分である酸化物をシリカ（二酸化ケイ素）とした場合について説明する。
この導電性粒子は、金属粒子の表面に、耐塩水性、耐酸性、耐酸化性、耐紫外線性に極めて優れたシリカ（二酸化ケイ素）からなる被覆層（以下、シリカ層とも称する）を形成することにより、金属粒子の耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性が著しく向上する。
また、被覆層の主成分をシリカとしたことにより、この導電性粒子を用いた透明導電膜形成用塗料により透明導電膜を形成した場合、透明導電膜とガラス等の基材との密着性が向上し、使用時においても、剥離、傷等の不具合が生じるおそれがなくなる。
【００７３】
金属粒子の表面にシリカ層を形成する方法としては、金属粒子、あるいはコロイド状の金属粒子を、水ガラス、有機ケイ素化合物等と混合して反応させる方法が採られる。これにより、金属粒子の表面に強固なシリカ層を形成することができる。
上記の金属粒子としては、Ａｇ、Ｃｕ、Ｎｉから選択された１種または２種以上を含有していることが好ましい。
【００７４】
上記の有機ケイ素化合物としては、トリメチルメトキシシラン、トリメチルエトキシシラン、ジメチルジメトキシシラン、ジメチルジエトキシシラン、メチルトリメトキシシラン、テトラメトキシシラン、メチルトリエトキシシラン、テトラエトキシシラン、メチルジメトキシシラン、ジメチルエトキシシラン、ジメチルビニルメトキシシラン、ジメチルビニルエトキシシラン、メチルビニルジメトキシシラン、メチルビニルジエトキシシラン、ジフェニルジメトキシシラン、フェニルトリメトキシシラン、ジフェニルジエトキシシラン、フェニルトリエトキシシラン、ビニルトリエトキシシラン、γ−クロロプロピルトリメトキシシラン、γ−クロロプロピルメチルジクロロシラン、γ−クロロプロピルメチルジメトキシシラン、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−アミノプロピルメチルジメトキシシラン、γ−メルカプト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メトキシシラン、γ−グリシドキシプロピルメチルジメトキシシラン、γ−メタクリロキシプロピルトリメトキシシラン、γ−メタクリオキシプロピルメチルジメトキシシラン等が好適に用いられる。
【００７５】
このシリカ被覆金属粒子は、塩水や、酸性または酸化性の液体またはガス等の劣化因子と長期間接触させても導電性に変化は見られない。したがって、このシリカ被覆金属粒子を用いて透明導電膜形成用塗料を作製すれば、得られる透明導電膜の帯電防止性あるいは電磁波遮蔽性を長期間にわたって維持することができる。
また、このシリカ被覆金属粒子の導電性は、いずれも１０^−５Ωｃｍ以下のレベルであり、成膜後の表面抵抗は１０^−１〜１０^３Ω／□のレベルであるから、実用的に十分な電磁波遮蔽性能を得ることができる。
【００７６】
このシリカ層は、さらに貴金属を含有していると、導電性が向上するため好ましい。また、この貴金属は、シリカ層の空隙中に析出していることが好ましい。
この貴金属としては、Ａｕ、Ｐｔ、Ｐｄ、Ｏｓ、Ｉｒ、Ｒｕ、Ｒｅ、Ｒｈ等が挙げられ、特に、Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕから選択された１種または２種以上であることが好ましい。
【００７７】
この貴金属を含むシリカ層により表面が被覆された表面被覆金属粒子は、シリカ層の空隙中に上述した貴金属を析出させることにより得ることができる。
ここで、シリカ層の空隙中に貴金属を析出させるには、上記のシリカ被覆金属粒子を、Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕから選択された１種または２種以上の金属塩を含む溶液に浸漬、あるいは該シリカ被覆金属粒子と該溶液を混合、等を行うことで両者を接触させる。
【００７８】
このシリカ被覆金属粒子では、その表面に形成されるシリカ層には空隙が形成されており、この空隙はシリカ層の表面から金属粒子の表面まで通じている。そこで、金属粒子最表面の原子を、Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕ等のイオンとイオン交換すれば、シリカ層の表面から金属粒子の表面に至るシリカ層の空隙中に、Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕ等を析出させることができ、表面が貴金属含有シリカ層で被覆された表面被覆金属粒子を容易に得ることができる。
このようにして得られた表面被覆金属粒子は、貴金属がシリカ層の表面から内部の金属粒子の表面まで通じて析出しているため、優れた導電性を示す。
【００７９】
以上により、貴金属を含むシリカ層により被覆された表面被覆金属粒子を得ることができる。この貴金属は、Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕから選択された１種または２種以上であるから、シリカ層の空隙中にＡｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕ等が存在することとなり、これらを通じて優れた導電性を呈することができる。
【００８０】
このシリカ被覆金属粒子、あるいは表面被覆金属粒子に、電気透析などの通常の洗浄方法を施すことで、コロイド状の分散液を得ることができる。
上記のシリカ被覆金属粒子、あるいは表面被覆金属粒子は、粒子表面に形成されたシリカの電気二重層による分散系であるから、従来の金属コロイドに比べて極めて安定性が高く、しかも金属粒子の濃度が高い分散液を得ることができる。
【００８１】
このようにして得られたコロイド状分散液を溶剤に添加することで、シリカ被覆金属粒子あるいは表面被覆金属粒子を主成分とする透明導電膜形成用塗料を得ることができる。溶剤としては、例えば、水や有機溶媒が挙げられ、親水性の有機溶媒としては、メタノール、エタノール、プロパノール、ブタノール等のアルコール類、あるいはβ−オキシエチルメチルエーテル（メチルセロソルブ）、β−オキシエチルエーテル（エチルセロソルブ）、ブチル−β−オキシエチルエーテル（ブチルセロソルブ）等のエーテル類を用いることができる。
【００８２】
この透明導電膜形成用塗料を、例えば、ガラス基板、耐熱性透明樹脂、ガラス板等の基材の表面に塗布することにより透明導電膜を得ることができる。
この様にして形成された透明導電膜は、金属粒子の表面に、耐環境性に優れたシリカ層あるいは貴金属を含むシリカ層が形成されているので、膜強度が著しく向上し、スクラッチ強度が向上する。
【００８３】
また、金属粒子の表面に、耐環境性に優れたシリカ層あるいは貴金属を含むシリカ層が形成されているので、ハロゲン、酸性、酸化性、紫外線などの雰囲気に対して耐性があり、これらの雰囲気に長期間暴露されることがあっても、金属粒子の変質に由来する導電性の低下、変色、膜強度の低下等を起こす虞がない。
さらに、金属粒子の表面にシリカ層あるいは貴金属を含むシリカ層が形成されているので、基材との密着性に優れたものとなる。
【００８４】
この透明導電膜は、例えば、プラズマディスプレイパネル（ＰＤＰ）、液晶ディスプレイ（ＬＣＤ）、エレクトロルミネッセンス（ＥＬ）ディスプレイ、タッチパネル、陰極線管（ＣＲＴ）等の各種表示装置の表示パネルに適用することができる。
また、建築物等の窓ガラス、自動車のフロントガラス、自動車のメーターパネル、電子レンジの覗き窓等の各種窓材等にも適用することができる。
【００８５】
上記の表示装置や各種窓材によれば、海上輸送時の海水やオペレーターの汗等からもたらされる食塩分等のハロゲン塩や、温泉地などにおける硫化水素ガス、さらに大気中のＳＯ_ｘガス、酸性雨等の酸性液体や酸性ガス、紫外線等により発生するオゾン等の酸化性ガス等に対する耐性が高く、これらの劣化因子を含む環境下に置かれても、長期間に亘って電磁波遮蔽性、反射防止性、色相、膜強度等の初期性能を維持することができる。
【００８６】
「導電性接着材料」
以下、本実施形態の導電性接着材料について説明する。
本実施形態の導電性接着材料は、本実施形態の導電性粒子を含有することを特徴とするもので、この導電性接着材料の形態としては、以下の４種類がある。
（１）本実施形態の導電性粒子と溶媒からなる導電性接着材料Ａ
（２）本実施形態の導電性粒子とバインダーからなる導電性接着材料Ｂ
（３）本実施形態の導電性粒子と溶媒とバインダーからなる導電性接着材料Ｃ
（４）上記の（１）〜（３）のいずれかを基材上に固着させた導電性接着材料Ｄ
【００８７】
次に、上記の導電性接着材料Ａ〜Ｄ各々について説明する。
「導電性接着材料Ａ」
この導電性接着材料は、本実施形態の導電性粒子をアニオン型、カチオン型、または高分子型等の界面活性剤を用いて、水、アルコール類、フェノール類、エステル類、ケトン類、エーテル類、芳香族化合物等の公知の溶媒に分散させたものである。
【００８８】
公知の溶媒の例として、アルコール類としては、メタノール、エタノール、プロパノール、ブタノール等が挙げられる。フェノール類としては、テレピネオールが挙げられる。エステル類としては、酢酸エチル、酢酸ブチルが挙げられる。ケトン類としてはメチルエチルケトン、メチルイソブチルケトンが挙げられる。
【００８９】
エーテル類としては、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールジメチルエーテル、エチレングリコール−ｎ−エキシルエーテルおよびそれらのアセテート、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノイソブチルエーテル、ジエチレングリコールモノヘキシルエーテルおよびそれらのアセテート、トリエチレングリコールモノアルキルおよびそれらのアセテートが挙げられる。
そのほかの溶媒としては，ジオキサン、ジメチルアセトアミド、ジメチルホルムアミド、Ｎ−メチルピロリドン、ラクトン等が挙げられる。
上記の溶媒は、少なくとも１種または２種以上を含むことが好ましい。
【００９０】
「導電性接着材料Ｂ」
この導電性接着材料は、本実施形態の導電性粒子と、バインダーとして熱可塑性樹脂、熱硬化性樹脂、電子線硬化性樹脂、感圧樹脂等の有機樹脂からなる有機バインダー、ポリシラン、金属アルコキシドの縮重合物等の有機金属バインダー、ガラスフリット等の無機バインダーを混合させた導電性接着材料である。
【００９１】
有機バインダーとしては、エチルセルロース、ヒドロキシエチルセルロース、メチルセルロース、ニトロセルロース、エチルセルロース誘導体、ポリビニルアルコール、ポリエチレンオキシド、ポリアルキレンオキシド、アクリル系樹脂、ブチラール樹脂、フェノール系樹脂、ポリウレタン樹脂、ポリエステル系樹脂、アルキッド樹脂、酢酸ビニル樹脂、エチレン−酢酸ビニル共重合体、スチレン系樹脂、エポキシ系樹脂、アミノ樹脂、ポリイミド樹脂、メラミンアルキッド樹脂、レゾール樹脂およびそれらの変性樹脂等から選択することができる。
【００９２】
「導電性接着材料Ｃ」
この導電性接着材料は、本実施形態の導電性粒子と、導電性接着材料Ａで用いた溶媒と、導電性接着材料Ｂで用いたバインダーとを混合させた導電性接着材料である。
【００９３】
「導電性接着材料Ｄ」
この導電性接着材料は、上記の導電性接着材料Ａ〜Ｃの導電性接着材料をプラスチックフィルム、プラスチック板、金属板、ガラス板等の基材上に塗布して形成させた導電性接着材料である。
【００９４】
これらの導電性接着材料Ａ〜Ｄには、必要に応じて各種の公知の添加剤を添加してもよい。例えば、公知の粘度調整剤、希釈剤、沈殿防止剤、レベリング剤、消泡剤などを添加してもよい。
【００９５】
これらの導電性接着材料Ａ〜Ｄが適用できる基板としては、特に限定されないが、下記のような基板を例示することができる。
ガラス基板、アルミニウム、ステンレススチール等の金属基板、アルミナ、窒化アルミニウム等のセラミック基板、シリコンウエハ、ガリウムヒ素ウエハ等の半導体基板、ガラスエポキシ樹脂基板、紙フェノール樹脂基板、ポリイミド基板、ポリエステル樹脂基板、ＢＴレジン基板、ポリサルフォン樹脂基板、ポリエーテルサルフォン樹脂基板、ポリエーテルイミド樹脂基板、ポリブタジエン樹脂基板、ガラスポリイミド樹脂基板等のフレキシブル基板や樹脂基板等が挙げられる。
【００９６】
本実施形態の導電性接着材料は、本実施形態の導電性粒子を含有したものであるから、導電性粒子の酸化や腐食による導電不良を生じることのない導電性接着材料を提供することができる。
また、この導電性接着材料は、各種電子機器等の電極形成、回路配線形成、導電接合、導電膜形成等に用いることができる。この導電性接着材料を用いて作製された電子機器等は、食塩分等のハロゲン塩や、温泉地などにおける硫化水素ガス、さらに大気中のＳＯ_ｘガス、酸性雨等の酸性液体や酸性ガス、紫外線等により発生するオゾン等の酸化性ガス等の劣化因子を含む過酷な環境下において使用されても、導電不良等のトラブルは極めて少ないものになる。
【００９７】
【実施例】
以下、実施例及び比較例により本発明を具体的に説明するが、本発明はこれらの実施例によって限定されるものではない。
【００９８】
［実施例１］
γ−アミノプロピルトリエトキシシランで表面処理された平均粒径０．１μｍのＡｇ粒子１００ｇに、エタノールにテトラエトキシシラン１３８ｇを溶解させた溶液２０００ｇを加え、これを５℃に保持しつつ攪拌し、さらに、２％アンモニア水２０ｇを添加して６時間攪拌した。次いで、これを濾過洗浄し、その後、１００℃で乾燥し、Ａｇ粒子の表面にシリカ層が形成されたシリカ被覆Ａｇ粒子を得た。
【００９９】
このシリカ被覆Ａｇ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、Ａｇ粒子の表面に約２０ｎｍのシリカ層が形成されていることが分かった。また、シリカ被覆Ａｇ粒子を元素分析したところ、Ｓｉ／Ａｇ＝０．０２７（重量比）であった。
【０１００】
次いで、このシリカ被覆Ａｇ粒子５０ｇを、Ａｕ／Ａｇ＝０．１０（重量比）となるようにＡｕ濃度を調整した塩化金酸溶液に加え、３０℃にて２時間攪拌し、シリカ層の内部と表面にＡｕ粒子が析出した導電性粒子を作製した。
この導電性粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、シリカ層の表面に約５ｎｍのＡｕ粒子が析出しているのが確認された。また、この導電性粒子を元素分析したところ、Ａｕ／Ａｇ＝０．０９９（重量比）であった。
【０１０１】
次いで、このシリカ被覆Ａｇ粒子の導電性及び耐酸性の評価を行った。
「導電性」
上記の導電性粒子を３００ｋｇ／ｃｍ^２の一軸荷重下で圧粉体とし、この圧粉体の比抵抗を測定したところ、８×１０^−６Ω・ｃｍであった。
【０１０２】
「耐酸性」
１ｍｏｌ％の塩酸１００ｇに上記の導電性粒子１ｇを加え、３０℃にて２４時間攪拌した後、濾過・洗浄し、その後１００℃にて乾燥し、評価用試料とした。
耐酸性の評価は、圧粉体の比抵抗の測定、粉末Ｘ線回折による反応生成物の同定、の２項目とした。
上記の比抵抗の測定方法にしたがって試験後の評価用試料の比抵抗を測定したところ、８×１０^−６Ω・ｃｍであり、試験後の比抵抗の上昇は認められなかった。
また、粉末Ｘ線回折のチャートでは、Ａｇ及びＡｕの回折線のみが現れており、塩化銀（ＡｇＣｌ）のような反応生成物の回折線は認められなかった。
【０１０３】
【表１】

【０１０４】
［比較例１］
実施例１で使用した平均粒径０．１μｍのＡｇ粒子について、実施例１と同様の方法により耐酸性の評価を行った。
Ａｇ粒子の比抵抗は、試験前で８×１０^−６Ω・ｃｍであったが、試験後は４×１０^３Ω・ｃｍと高くなっており、耐酸性試験により導電性が悪化していることが認められた。
また、粉末Ｘ線回折のチャートでは、Ａｇの回折線の他に、反応生成物としての塩化銀（ＡｇＣｌ）の回折線が認められた。
【０１０５】
【表２】

【０１０６】
［実施例２］
実施例１にて作製したシリカ被覆Ａｇ粒子５０ｇを、Ｐｄ／Ａｇ＝０．０５（重量比）となるようにＰｄ濃度を調整した酢酸パラジウム溶液に加え、３０℃にて２時間攪拌し、シリカ層の内部と表面にＰｄ粒子が析出した導電性粒子を作製した。
この導電性粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、シリカ層の表面に約５ｎｍのＰｄ粒子が析出しているのが確認された。また、この導電性粒子を元素分析したところ、Ｐｄ／Ａｇ＝０．０５１（重量比）であった。
【０１０７】
この導電性粒子について、実施例１と同様の方法により耐酸性の評価を行った。
実施例１の比抵抗の測定方法にしたがって、この導電性粒子の比抵抗を測定したところ、耐酸性試験の前後共に８×１０^−６Ω・ｃｍであり、耐酸性試験後の抵抗率の上昇は認められなかった。
また、粉末Ｘ線回折のチャートでは、Ａｇ及びＰｄの回折線のみが現れており、塩化銀（ＡｇＣｌ）のような反応生成物の回折線は認められなかった。
【０１０８】
【表３】

【０１０９】
［実施例３］
γ−アミノプロピルトリエトキシシランで表面処理された平均粒径０．３μｍのＣｕ粒子１００ｇに、エタノールにアルミニウムブトキシド４８．２ｇを溶解した溶液２０００ｇを加え、この溶液を５℃に保持しつつ攪拌し、さらに、０．１％アンモニア水２０ｇを添加して６時間攪拌した。次いで、これを濾過洗浄し、その後、１００℃で乾燥し、Ｃｕ粒子の表面にアルミナ層が形成されたアルミナ被覆Ｃｕ粒子を得た。
【０１１０】
このアルミナ被覆Ｃｕ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、Ｃｕ粒子の表面に約２０ｎｍのアルミナ層が形成されているのが分かった。また、このアルミナ被覆Ｃｕ粒子を元素分析したところ、Ａｌ／Ｃｕ＝０．００７３（重量比）であった。
【０１１１】
次いで、このアルミナ被覆Ｃｕ粒子５０ｇを、Ｐｔ／Ｃｕ＝０．１（重量比）となるようにＰｔ濃度を調整した塩化白金酸溶液に加え、３０℃にて２時間攪拌し、アルミナ層の内部と表面にＰｔ粒子が析出した導電性粒子（アルミナ−Ｐｔ被覆Ｃｕ粒子）を作製した。
この導電性粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、アルミナ層の表面に約５ｎｍのＰｔ粒子が析出しているのが確認された。また、この導電性粒子を元素分析したところ、Ｐｔ／Ｃｕ＝０．０９９（重量比）であった。
【０１１２】
この導電性粒子について耐酸化性の評価を行った。
「耐酸化性」
作製した導電性粒子を凍結乾燥して得た粉末を、空気中にて１５０℃で１時間加熱処理し、評価用試料とした。
耐酸化性の評価は、圧粉体の比抵抗の測定、粉末Ｘ線回折による反応生成物の同定、の２項目とした。
【０１１３】
実施例１の比抵抗の測定方法にしたがって比抵抗を測定したところ、耐酸化性試験前では８×１０^−６Ω・ｃｍ、試験後では９×１０^−６Ω・ｃｍであり、耐酸化性試験後の抵抗率の上昇は僅かであった。
また、粉末Ｘ線回折のチャートでは、Ｃｕ及びＰｔの回折線のみが現れており、酸化銅（ＣｕＯ）のような反応生成物の回折線は認められなかった。
【０１１４】
【表４】

【０１１５】
［比較例２］
実施例３で使用した平均粒径０．３μｍのＣｕ粒子について、実施例３と同様の方法により耐酸化性の評価を行った。
実施例１の比抵抗の測定方法にしたがって比抵抗を測定したところ、試験前では８×１０^−６Ω・ｃｍであったが、試験後は４×１０^−１Ω・ｃｍと上昇しており、耐酸化性試験により導電性が悪化していることが認められた。
また、粉末Ｘ線回折のチャートでは、Ｃｕの回折線の他に、反応生成物としての酸化銅（ＣｕＯ）の回折線が認められた。
【０１１６】
【表５】

【０１１７】
次に、以下の実施例及び比較例にて用いられる導電性粒子およびその分散液及び低屈折率塗料を以下の方法により作製した。
「金属粒子の作製」
次の２種類の溶液を作製した。
（溶液ａ）
硝酸銀１７００ｇを水９ｋｇに溶解し、溶液ａとした。
（溶液ｂ）
水素化硼素ナトリウム４０ｇとクエン酸ナトリウム９００ｇを水５０ｋｇに溶解し、溶液ｂとした。
【０１１８】
次いで、この溶液ｂを攪拌しながら、この溶液ｂに上記の溶液ａを徐々に加え、Ａｇ粒子を含む溶液を作製した。得られたＡｇ粒子を透過型電子顕微鏡（ＴＥＭ）で観察したところ、その粒径は約１５ｎｍであった。
このＡｇ粒子を含む溶液を遠心分離操作により洗浄し、コロイド状のＡｇ粒子分散液Ａを得た。このＡｇ粒子分散液Ａ中のＡｇ粒子の濃度は１．５０重量％であった。
【０１１９】
「表面修飾剤を吸着したＡｇ粒子分散液の作製」
γ−メルカプトプロピルトリメトキシシラン７．５ｇを水４００ｇに溶解し、溶液ｃとした。
次いで、上記のＡｇ粒子分散液Ａ１０ｋｇに上記の溶液ｃを加えて攪拌し、γ−メルカプトプロピルトリメトキシシランが吸着したＡｇ粒子分散液Ｂを作製した。
【０１２０】
「Ａｇ粒子表面へのジルコニア層の形成」
次の溶液を作製した。
（溶液ｄ）
ジルコニウムブトキシド３００ｇをエタノール２０００ｇに溶解し、溶液ｄとした。
次いで、上記のＡｇ粒子分散液Ｂに上記の溶液ｄを滴下しながら加え、その後４０℃にて５時間攪拌し、表面がジルコニア層で被覆されたジルコニア被覆Ａｇ粒子を作製した。
【０１２１】
このジルコニア被覆Ａｇ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、ジルコニア層の厚みはほぼ２ｎｍであった。
このジルコニア被覆Ａｇ粒子の懸濁した液を、遠心分離操作により洗浄し、その後エバポレータを用いてジルコニア被覆Ａｇ粒子の濃度を１５重量％まで濃縮し、コロイド状のジルコニア被覆Ａｇ粒子分散液Ｃを作製した。
【０１２２】
「Ａｇ粒子表面へのＰｄを含むジルコニア層の形成」
次の溶液を作製した。
（溶液ｅ）
硝酸パラジウム４１ｇを水１ｋｇに溶解し、溶液ｅとした。
次いで、上記のジルコニア被覆Ａｇ粒子分散液Ｃ３６００ｇに水４５ｋｇを加え、さらに上記の溶液ｅを加えて２時間攪拌し、ジルコニア層中および表面の一部にＰｄを析出させ、Ａｇ粒子の表面にＰｄを含むジルコニア層が形成されたジルコニア−Ｐｄ被覆Ａｇ粒子を得た。
【０１２３】
このジルコニア−Ｐｄ被覆Ａｇ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、粒径が１ｎｍのＰｄ粒子がジルコニア層中および表面の一部に均一に析出していることが分かり、Ｐｄを含むジルコニア層の存在が確かめられた。
また、このジルコニア−Ｐｄ被覆Ａｇ粒子のＡｇとＰｄを化学分析により分析したところ、Ｐｄ／Ａｇ＝０．０３６（重量比）であった。
その後、遠心分離操作により洗浄した後、エバポレータを用いてジルコニア−Ｐｄ被覆Ａｇ粒子の濃度を１５重量％まで濃縮し、ジルコニア−Ｐｄ被覆Ａｇ粒子分散液Ｄを得た。
【０１２４】
「低屈折率塗料の調整」
テトラエトキシシラン８０ｇと、０．１Ｎの塩酸８０ｇと、エタノール９８４０ｇとを混合し、低屈折率塗料Ｅを調整した。
【０１２５】
「Ａｇ粒子表面へのシリカ層の形成」
次の溶液を作製した。
（溶液ｆ）
水ガラス（ＳｉＯ_２換算２７ｗｔ％）１５ｇを水１ｋｇに溶解し、溶液ｆとした。
次いで、上記のコロイド状のＡｇ粒子分散液Ａに上記の溶液ｆを加えて２４時間攪拌し、表面がシリカ層で被覆されたシリカ被覆Ａｇ粒子を作製した。
【０１２６】
このシリカ被覆Ａｇ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、シリカ層の厚みはほぼ５ｎｍであった。
このシリカ被覆Ａｇ粒子の懸濁した液を、遠心分離操作により洗浄し、その後エバポレータを用いてシリカ被覆Ａｇ粒子の濃度を１５重量％まで濃縮し、コロイド状のシリカ被覆Ａｇ粒子分散液Ｆを作製した。
【０１２７】
「Ａｇ粒子表面へのＡｕを含むシリカ層の形成」
次の溶液を作製した。
（溶液ｇ）
塩化金酸（Ｈ［ＡｕＣｌ_４］・２Ｈ_２Ｏ）１１３ｇを水１ｋｇに溶解し、溶液ｇとした。
次いで、上記のシリカ被覆Ａｇ粒子分散液Ｆ３６００ｇに水４５ｋｇを加え、さらに溶液ｇを加えて２時間攪拌し、Ａｇ粒子を覆うシリカ層中にＡｕを析出させ、Ａｇ粒子の表面にＡｕを含むシリカ層が形成されたシリカ−Ａｕ被覆Ａｇ粒子を得た。
【０１２８】
このシリカ−Ａｕ被覆Ａｇ粒子を透過型電子顕微鏡（ＴＥＭ）を用いて観察したところ、粒径が１ｎｍのＡｕ粒子がシリカ層中および表面の一部に析出していることが分かり、Ａｕを含むシリカ層の存在が確かめられた。
また、このシリカ−Ａｕ被覆Ａｇ粒子のＡｇとＡｕを化学分析により分析したところ、Ａｕ／Ａｇ＝０．１０６（重量比）であった。
その後、遠心分離操作により洗浄した後、エバポレータを用いてシリカ−Ａｕ被覆Ａｇ粒子の濃度を１５重量％まで濃縮し、シリカ−Ａｕ被覆Ａｇ粒子分散液Ｇを得た。
【０１２９】
［実施例４］
「透明導電膜形成用塗料の調整」
ジルコニア被覆Ａｇ粒子分散液Ｃ ２ｇ
純水 ７８ｇ
ブチルセロソルブ １０ｇ
イソプロピルアルコール １０ｇ
を秤量し、これらを混合し、その後、超音波分散機で均一に分散させることにより、透明導電膜形成用塗料Ｈを得た。
【０１３０】
「成膜」
この透明導電膜形成用塗料Ｈを、陰極線管（ＣＲＴ）の表面にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｅをスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後、乾燥機で１５０℃の温度下で１時間焼き付け、反射防止機能付き透明導電膜（低反射透明導電膜）を有する陰極線管を得た。
【０１３１】
［実施例５］
「透明導電膜形成用塗料の調整」
ジルコニア−Ｐｄ被覆Ａｇ粒子分散液Ｄ ２ｇ
純水 ７８ｇ
ブチルセロソルブ １０ｇ
イソプロピルアルコール １０ｇ
を秤量し、これらを混合し、その後、超音波分散機で均一に分散させることにより、透明導電膜形成用塗料Ｊを得た。
【０１３２】
「成膜」
この透明導電膜形成用塗料Ｊを、陰極線管（ＣＲＴ）の表面にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｅをスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後、乾燥機で１５０℃の温度下で１時間焼き付け、反射防止機能付き透明導電膜（低反射透明導電膜）を有する陰極線管を得た。
【０１３３】
［実施例６］
「透明導電膜形成用塗料の調整」
シリカ被覆Ａｇ粒子分散液Ｆ ２ｇ
純水 ７８ｇ
ブチルセロソルブ １０ｇ
イソプロピルアルコール １０ｇ
を秤量し、これらを混合し、その後、超音波分散機で均一に分散させることにより、透明導電膜形成用塗料Ｋを得た。
【０１３４】
「成膜」
この透明導電膜形成用塗料Ｋを、陰極線管（ＣＲＴ）の表面にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｅをスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後、乾燥機で１５０℃の温度下で１時間焼き付け、反射防止機能付き透明導電膜（低反射透明導電膜）を有する陰極線管を得た。
【０１３５】
［実施例７］
「透明導電膜形成用塗料の調整」
シリカ−Ａｕ被覆Ａｇ粒子分散液Ｇ ２ｇ
純水 ７８ｇ
ブチルセロソルブ １０ｇ
イソプロピルアルコール １０ｇ
を秤量し、これらを混合し、その後、超音波分散機で均一に分散させることにより、透明導電膜形成用塗料Ｌを得た。
【０１３６】
「成膜」
この透明導電膜形成用塗料Ｌを、陰極線管（ＣＲＴ）の表面にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｅをスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後、乾燥機で１５０℃の温度下で１時間焼き付け、反射防止機能付き透明導電膜（低反射透明導電膜）を有する陰極線管を得た。
【０１３７】
［比較例３］
「透明導電膜形成用塗料の調整」
Ａｇ粒子分散液Ａ ２０ｇ
純水 ６０ｇ
ブチルセロソルブ １０ｇ
イソプロピルアルコール １０ｇ
を秤量し、これらを混合し、その後、超音波分散機で均一に分散させることにより、透明導電膜形成用塗料Ｍを得た。
【０１３８】
「成膜」
この透明導電膜形成用塗料Ｍを、陰極線管（ＣＲＴ）の表面にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｅをスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後、乾燥機で１５０℃の温度下で１時間焼き付け、反射防止機能付き透明導電膜（低反射透明導電膜）を有する陰極線管を得た。
【０１３９】
「評価」
以上により得られた実施例４〜７及び比較例３の反射防止機能付き透明導電膜（低反射透明導電膜）の表面抵抗値、反射率、透過率、耐擦傷性、耐ＨＣｌ（塩酸）性、耐ＮａＣｌ（塩水）性、耐Ｈ_２Ｏ_２（過酸化水素）性、塗料安定性の各項目について、次の方法及び装置を用いて評価した。
【０１４０】

【０１４１】

【０１４２】

実施例４〜７及び比較例３の評価結果を表６〜表９に示す。
【０１４３】
【表６】

【０１４４】
【表７】

【０１４５】
【表８】

【０１４６】
【表９】

【０１４７】
表６〜表９の結果によれば、実施例４〜７では、全ての評価項目において良好な結果を得ており、透明性、導電性、帯電防止性等に優れているばかりでなく、耐ＨＣｌ性、耐ＮａＣｌ性、耐Ｈ_２Ｏ_２性等の耐環境性、耐擦傷性が良好であることが確認された。また、塗料安定性も良好であることが確認された。
【０１４８】
一方、比較例３では、透明性、導電性、帯電防止性等については、実施例４〜７と遜色ないものの、耐ＨＣｌ性及び耐ＮａＣｌ性では、膜が剥離してしまい、表面抵抗を測定することができなかった。また、耐Ｈ_２Ｏ_２性では、外観は変化が認められないものの、表面抵抗変化率が１０００％を超えており、高抵抗層もしくは絶縁層に変化していることが分かった。また、塗料安定性では、沈殿物が発生し、塗料の変質が認められた。
【０１４９】
［実施例８］
実施例１で得られた導電性粒子（シリカ−Ａｕ被覆Ａｇ粒子）２００ｇに、セバシン酸４ｇ、トリエタノールアミン２ｇ、ブチルセルソルブ８０ｇ、レゾール樹脂２０ｇを加え、遊星ミルで予備混合した後、３本ロールミルにて混練し、導電性接着材料を作製した。次いで、この導電性接着材料を用いて、ＢＴレジン基板上にスクリーン印刷機にて２００μｍ幅のライン、４０μｍのスペースのテストパターンを印刷し、その後、１６０℃で乾燥硬化させ、導線パターンを形成した。
この導線パターンが形成された基板に対して通電試験を行った。
９０℃−相対湿度９０％の高温高湿下にて、基板上の導線に１０Ｖの直流電圧を印加しながら１０００時間の通電試験を行った。結果を表１０に示す。
【０１５０】
【表１０】

表１０によれば、導線パターンの比抵抗は、試験前では２×１０^−５Ω・ｃｍであり、５００時間通電後は３×１０^−５Ω・ｃｍ、１０００時間通電後も３×１０^−５Ω・ｃｍであり、通電試験の前後における比抵抗の変化は僅かなものであった。
【０１５１】
［比較例４］
導電性粒子として０．１μｍのＡｇ粒子を用いた以外は、実施例８と同様の方法により導電性接着材料を作製し、実施例８と同様の評価を行った。結果を表１１に示す。
【０１５２】
【表１１】

表１１によれば、導線パターンの比抵抗は、試験前では２×１０^−５Ω・ｃｍであったが、５００時間通電後は４×１０^−５Ω・ｃｍと高くなっており、１０００時間通電後ではショートによる導通不良が発生した。
【０１５３】
［実施例９］
実施例３で得られた導電性粒子（アルミナ−Ｐｔ被覆Ｃｕ粒子）２００ｇに、ＰｂＯ−ＺｎＯ−Ｂ_２Ｏ_３ガラスフリット（平均粒径１．６μｍ）１２ｇ、エチルセルロース０．５ｇ、テレピネオール１８ｇを加え、遊星ミルで予備混合した後、３本ロールミルで混練し、導電性接着材料を作製した。次いで、この導電性接着材料を用いて、アルミナ基板上にスクリーン印刷機にて２００μｍ幅のライン、４０μｍのスペースのテストパターンを印刷し、その後、空気中および窒素雰囲気中のそれぞれの雰囲気中にて８５０℃で焼成し、導線パターンを形成した。
その後、この導線パターンが形成された基板の導電性を評価した。
【０１５４】
【表１２】

表１２によれば、導線パターンの比抵抗は、空気中焼成、窒素雰囲気焼成共に、４×１０^−６Ω・ｃｍであり、導電性粒子としてアルミナ−Ｐｔ被覆Ｃｕ粒子を用いた場合には、空気中焼成、窒素雰囲気焼成のいずれの焼成方法によっても導電性が十分に確保されていることが分かった。
【０１５５】
［比較例５］
導電性粒子として０．３μｍのＣｕ粒子を用いた以外は、実施例９と同様の方法により導電性接着材料を作製し、実施例９と同様の評価を行った。結果を表１３に示す。
【０１５６】
【表１３】

表１３によれば、導線パターンの比抵抗は、空気中焼成では８×１０^−１Ω・ｃｍと高かったのに対し、窒素雰囲気焼成では４×１０^−６Ω・ｃｍと低く、空気中焼成では導電性が確保されないことが分かった。
【０１５７】
次に、以下の実施例にて用いられるＡｇコロイド分散液及び低屈折率塗料を以下の方法により作製した。
「Ａｇコロイド分散液の作製」
０．１５ｍｍｏｌ／ｌの硝酸銀水溶液と、０．０２４ｍｍｏｌ／ｌの水素化ホウ素ナトリウム水溶液とを混合し、得られたコロイド状分散液を濃縮し、０．６５ｍｏｌ／ｌのＡｇ微粒子を含むＡｇコロイド分散液Ｎを得た。このＡｇコロイド分散液Ｎ中の銀微粒子の平均一次粒子径は１０ｎｍであった。
テトラエトキシシラン０．８ｇと、０．１Ｎ塩酸０．８ｇと、エタノール９８．４ｇとを混合して均一な溶液とすることにより、低屈折率塗料Ｐを得た。
【０１５８】
［実施例１０］
「溶液の調整」
次の２種類の溶液を作製した。
（溶液ｎ）
Ａｇコロイド分散液Ｎ９３ｇを純水４リットル中に分散した後、０．１ＮのＮａＯＨ水溶液を用いてこの分散液のｐＨを１０に調整し、溶液ｎとした。
（溶液ｐ）
タングステン酸ナトリウムを、上記溶液ｎのＡｇ固形分に対して１０ｍｏｌ％になるように秤量し、純水１リットルに溶解し、溶液ｐとした。
【０１５９】
次いで、この溶液ｎを攪拌しながら、この溶液ｎに上記の溶液ｐを５時間かけて滴下した。さらに、この溶液Ｐ中のタングステン酸ナトリウムと同モル量の水酸化ホウ素ナトリウムを純水１リットルに溶解した溶液を加え、得られた溶液に０．０５Ｎ酢酸を１時間かけて滴下し、ｐＨを４．０に調整した。
次いで、この溶液を室温（２５℃）にて２４時間攪拌した後、濾過洗浄することにより余分なイオン等を除去した。その後、この濃縮液をさらに２００ｍｌまで濃縮し、固形分が３重量％の酸化タングステン被覆Ａｇコロイド分散液Ｒを得た。
【０１６０】
「透明導電膜形成用塗料の調整」
酸化タングステン被覆Ａｇコロイド分散液Ｒ ２ｇ
エタノール ４３ｇ
純水 ３ｇ
エチルソロソルブ ２ｇ
を混合した後、超音波分散機（ソニファイヤー４５０：ＢＲＡＮＳＯＮ ＵＬＴＲＡＳＯＮＩＣＳ社製）で均一に分散し、透明導電膜形成用塗料Ｓを得た。
【０１６１】
「成膜」
この透明導電膜形成用塗料Ｓを、ガラス基板上にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｐを同様の方法により塗布し、次いで、このガラス基板を１６０℃で３０分加熱処理し、その後、放冷し、透明導電膜付ガラス基板を得た。
【０１６２】
［実施例１１］
「溶液の調整」
次の溶液を作製した。
実施例１０で得られた余分なイオン等が除去された濃縮液に純水を加えて全量を４リットルとし、さらに０．１ＮのＮａＯＨ水溶液を用いてこの溶液のｐＨを１０に調整し、溶液ｒとした。
【０１６３】
また、亜硫酸金ナトリウム（ＮａＡｕＳＯ_３）溶液を、上記の溶液ｒ中のＡｇ固形分に対してＡｕが３ｗｔ％となるように秤量し、さらに純水を加えて全量が１リットルの溶液ｓとした。
この溶液ｓを上記の溶液ｒに３時間かけて滴下した。得られた溶液に０．１Ｎ酢酸を１時間かけて滴下し、ｐＨを４．０に調整した。
次いで、この溶液を室温（２５℃）にて２４時間攪拌した後、濾過洗浄することにより余分なイオン等を除去した。その後、この濃縮液をさらに２００ｍｌまで濃縮し、固形分が５重量％の酸化タングステン−Ａｕ被覆Ａｇコロイド分散液Ｔを得た。
【０１６４】
「透明導電膜形成用塗料の調整」
酸化タングステン−Ａｕ被覆Ａｇコロイド分散液Ｔ ２ｇ
エタノール ４３ｇ
純水 ３ｇ
エチルソロソルブ ２ｇ
を混合した後、超音波分散機（ソニファイヤー４５０：ＢＲＡＮＳＯＮ ＵＬＴＲＡＳＯＮＩＣＳ社製）で均一に分散し、透明導電膜形成用塗料Ｕを得た。
【０１６５】
「成膜」
この透明導電膜形成用塗料Ｕを、ガラス基板上にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｐを同様の方法により塗布し、次いで、このガラス基板を１６０℃で３０分加熱処理し、その後、放冷し、透明導電膜付ガラス基板を得た。
【０１６６】
［実施例１２］
「溶液の調整」
Ａｇコロイド分散液Ｎ９３ｇを純水４リットル中に分散した後、０．１Ｎ酢酸を用いてこの分散液のｐＨを４．８に調整し、溶液ｔとした。
次いで、ＭＰＳ（γ−メルカプトトリエトキシシラン）を、上記溶液ｔのＡｇ固形分に対して４ｍｏｌ％になるように秤量し、純水０．５リットルに溶解し、この溶液を上記溶液ｔに、ｐＨを４．８に保ちつつ徐々に添加し、その後、１５分間撹拌し、溶液ｕとした。
【０１６７】
次いで、この溶液ｕに、モリブデン酸ナトリウムを上記溶液ｕのＡｇ固形分に対して１０ｍｏｌ％になるように秤量し純水０．５リットルに溶解したものを加え、さらに、次亜リン酸ナトリウムを前記モリブデン酸ナトリウムと同モルになるように秤量し純水０．３リットルに溶解したものを加えた。
次いで、この溶液に、０．０５Ｎ酢酸を１時間かけて滴下し、ｐＨを４．０に調整し、溶液ｖとした。
【０１６８】
次いで、この溶液ｖを室温（２５℃）にて２４時間攪拌した後、濾過洗浄することにより余分なイオン等を除去した。その後、この濃縮液をさらに２００ｍｌまで濃縮し、固形分が５重量％の酸化モリブデン被覆Ａｇコロイド分散液Ｖを得た。
【０１６９】
「透明導電膜形成用塗料の調整」
酸化モリブデン被覆Ａｇコロイド分散液Ｖ ２ｇ
エタノール ４３ｇ
純水 ３ｇ
エチルソロソルブ ２ｇ
を混合した後、超音波分散機（ソニファイヤー４５０：ＢＲＡＮＳＯＮ ＵＬＴＲＡＳＯＮＩＣＳ社製）で均一に分散し、透明導電膜形成用塗料Ｗを得た。
【０１７０】
「成膜」
この透明導電膜形成用塗料Ｗを、ガラス基板上にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｐを同様の方法により塗布し、次いで、このガラス基板を１６０℃で３０分加熱処理し、その後、放冷し、透明導電膜付ガラス基板を得た。
【０１７１】
［実施例１３］
「溶液の調整」
実施例１２で得られた余分なイオン等が除去された濃縮液に純水を加えて全量を４リットルとし、次いで、０．１ＮのＮａＯＨ水溶液を用いてこの溶液のｐＨを１０に調整し、溶液ｗとした。
【０１７２】
次いで、この溶液ｗに、実施例１１の溶液ｓを３時間かけて滴下した。得られた溶液に０．１Ｎ酢酸を１時間かけて滴下し、ｐＨを４．０に調整した。
次いで、この溶液を室温（２５℃）にて２４時間攪拌した後、濾過洗浄することにより余分なイオン等を除去した。その後、この濃縮液をさらに２００ｍｌまで濃縮し、固形分が５重量％の酸化モリブデン−Ａｕ被覆Ａｇコロイド分散液Ｘを得た。
【０１７３】
「透明導電膜形成用塗料の調整」
酸化モリブデン−Ａｕ被覆Ａｇコロイド分散液Ｘ ２ｇ
エタノール ４３ｇ
純水 ３ｇ
エチルソロソルブ ２ｇ
を混合した後、超音波分散機（ソニファイヤー４５０：ＢＲＡＮＳＯＮ ＵＬＴＲＡＳＯＮＩＣＳ社製）で均一に分散し、透明導電膜形成用塗料Ｙを得た。
【０１７４】
「成膜」
この透明導電膜形成用塗料Ｙを、ガラス基板上にスピンコータを用いて１５０ｒｐｍ−３０秒の条件で塗布し、その後乾燥させ、透明導電層とした。
次いで、この透明導電層の上に、上記の低屈折率塗料Ｐを同様の方法により塗布し、次いで、このガラス基板を１６０℃で３０分加熱処理し、その後、放冷し、透明導電膜付ガラス基板を得た。
【０１７５】
「評価」
以上により得られた実施例１０〜１３の透明導電膜付ガラス基板の表面抵抗値、反射率、透過率、耐擦傷性、耐ＨＣｌ（塩酸）性、耐ＮａＣｌ（塩水）性、耐Ｈ_２Ｏ_２（過酸化水素）性、塗料安定性の各項目について評価した。
評価方法は、上記の実施例４〜７及び比較例３の反射防止機能付き透明導電膜（低反射透明導電膜）の評価方法と全く同様とした。
実施例１０〜１３の評価結果を表１４〜表１７に示す。
【０１７６】
【表１４】

【０１７７】
【表１５】

【０１７８】
【表１６】

【０１７９】
【表１７】

【０１８０】
表１４〜表１７の結果によれば、実施例１０〜１３では、全ての評価項目において良好な結果を得ており、透明性、導電性、帯電防止性等に優れているばかりでなく、耐ＨＣｌ性、耐ＮａＣｌ性、耐Ｈ_２Ｏ_２性等の耐環境性、耐擦傷性が良好であることが確認された。また、塗料安定性も良好であることが確認された。
【０１８１】
【発明の効果】
以上説明したように、本発明の導電性粒子によれば、金属粒子の表面に酸化物からなる被覆層を形成したので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１８２】
本発明の導電性接着材料によれば、本発明の導電性粒子を含有したので、導電性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１８３】
本発明の透明導電膜形成用塗料によれば、本発明の導電性粒子を含有したので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
また、金属粒子の表面に酸化物からなる被覆層が形成されているので、この透明導電膜形成用塗料を用いて形成される透明導電膜とガラス等の基材との密着性を向上させることができる。したがって、使用時においても、剥離、傷等の不具合が生じる虞がない。
【０１８４】
本発明の透明導電膜によれば、本発明の透明導電膜形成用塗料を塗布してなる透明導電層を備えたので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
また、この透明導電膜とガラス等の基材との密着性が向上するので、使用時においても、剥離、傷等の不具合が生じる虞がない。
【０１８５】
本発明の表示装置によれば、本発明の透明導電膜を表示面に形成したので、表示面が透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
また、この表示面と透明導電膜との密着性が向上するので、使用時においても剥離、傷等の不具合が生じる虞がなく、表示面における視認性、信頼性等を向上させることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態の導電性粒子を示す断面図である。
【図２】本発明の一実施形態の導電性粒子の被覆層の断面構造の一例を示す模式図である。
【図３】本発明の一実施形態の導電性粒子の被覆層の断面構造の他の一例を示す模式図である。
【図４】本発明の一実施形態の透明導電膜を示す断面図である。
【図５】本発明の一実施形態の低反射透明導電膜を示す断面図である。
【図６】本発明の一実施形態の低反射透明導電膜の変形例を示す断面図である。
【図７】本発明の一実施形態の低反射透明導電膜の他の変形例を示す断面図である。
【図８】本発明の一実施形態の表示装置の表示面を示す断面図である。
【符号の説明】
１ 金属粒子
２ 被覆層
３ 酸化物層
４ 第２の金属粒子
５ 被覆層
１１ ガラス基板
１２ 透明導電層
２１ 反射防止層
２２、３１、４１ 低反射透明導電膜
５１ 表示パネル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is excellent in environmental resistance such as acid resistance, salt water resistance and the like and conductive particles having excellent conductivity, a conductive adhesive material containing the same, a paint for forming a transparent conductive film and a transparent conductive film using the same, and More specifically, the display device includes display surfaces of various display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), and a cathode ray tube (CRT), a window glass of a building and the like, and various windows of a windshield of an automobile and the like. A transparent conductive film that is suitable for use as a material, has an excellent antistatic effect, an excellent electromagnetic wave shielding effect, and is capable of forming a transparent conductive film having excellent environmental resistance such as acid resistance and salt water resistance. Conductive particles suitable for use in forming paints, a conductive adhesive material having excellent conductivity as well as being excellent in environmental resistance such as acid resistance and salt water resistance by containing the conductive particles, and the conductive particles described above. A transparent conductive film forming coating having a transparent conductive film using the transparent conductive film forming coating, to a display apparatus provided with the transparent conductive film.
[0002]
[Prior art]
Conventionally, for example, in various flat displays such as a plasma display panel (PDP), a liquid crystal display (LCD), and an electroluminescence (EL) display, or a cathode ray tube (CRT), an antistatic function and an electromagnetic wave shielding function are provided on the display surface. In order to provide such properties, a transparent conductive film forming paint having excellent antistatic performance and electromagnetic wave shielding performance is applied to a display surface to form a transparent conductive film.
On the other hand, in the case of various window materials such as window glasses of buildings, windshields of automobiles, etc., in order to provide an infrared shielding function, an electromagnetic shielding function, etc., a transparent conductive film having excellent infrared shielding performance and electromagnetic shielding performance is formed. 2. Description of the Related Art A transparent conductive film is formed by applying a paint for display on a display surface.
Also, with the rapid progress of electronics, various conductive adhesive materials have been proposed and used for various electronic devices, electronic components, electronic circuits, optical circuits, and the like.
[0003]
As a commonly used coating material for forming a transparent conductive film, a coating material in which metal fine particles such as silver (Ag), gold (Au), ruthenium (Ru), and palladium (Pd) are dispersed in a base containing a solvent and a binder is used. Is used.
In this coating for forming a transparent conductive film, various properties such as antistatic performance, electromagnetic wave shielding performance, infrared shielding performance, etc. are controlled by controlling the composition, particle size, dispersibility, etc. of the contained metal fine particles to obtain desired characteristics. Is to be expressed.
Examples of the conductive particles used in the paint for forming a transparent conductive film include at least two kinds of noble metal fine particles such as Ag fine particles and Pd fine particles, or those containing noble metal alloy fine particles such as an Ag-Pd type (for example, see Patent Literature). 1) and a metal fine particle formed with a coating made of a metal sulfide (for example, see Patent Document 2).
[0004]
[Patent Document 1]
Patent application re-publication WO97 / 48107
[Patent Document 2]
JP-A-10-204336 (page 3-5, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, the conductive particles used in the above-described conventional transparent conductive film forming paint, for example, when Ag fine particles are used as metal fine particles, although the manufacturing cost can be reduced, the Ag fine particles themselves are corroded by acid or salt water. There was a problem that it was easy. For this reason, paints made using Ag fine particles also have a problem in that they have poor environmental resistance such as acid resistance and salt water resistance, and therefore cannot be used for those requiring environmental resistance. .
Further, when fine particles of Au, Ru, Pd, etc. are used as metal fine particles, since these fine particles have excellent resistance to acid and salt water, paints made using these are also resistant to acid resistance. However, these metal fine particles are more expensive than Ag, Cu, Ni, etc., and thus have a problem that the production cost is higher. Was.
[0006]
Therefore, in order to improve the environmental resistance such as acid resistance and salt water resistance of Ag fine particles, paint for forming an Ag-Pd-based transparent conductive film using a mixed powder of Ag fine particles and Pd fine particles, or Ag-Pd alloy fine particles There have been proposed paints for forming an Ag-Pd alloy-based transparent conductive film using the same, but these paints were insufficient for improving environmental resistance such as acid resistance and salt water resistance.
Further, since the transparent conductive film formed using the transparent conductive film forming paint containing metal fine particles as a main component has little or very weak adhesion to a substrate such as glass, the transparent conductive film is transparent to the substrate. Adhesion between the conductive film and the conductive film is weak, and during use, various problems such as easy peeling and easy damage may occur.
[0007]
On the other hand, in the case of conductive adhesive materials, metal powders such as Ag, Cu, and Ni are usually used. However, since these metal powders are inferior in oxidation resistance and chemical resistance, a small amount of this conductive adhesive material is used. When used in an atmosphere containing a corrosive gas such as an acidic gas or an alkaline gas, the electric characteristics are lowered and the reliability is deteriorated. Therefore, it has been desired to develop a conductive powder which is excellent in chemical durability such as oxidation resistance and chemical resistance and is inexpensive.
In order to solve such a problem, Cu-Ag alloy powder has been proposed as a conductive powder having improved oxidation resistance. However, even with this Cu-Ag alloy powder, the improvement of environmental resistance is not sufficient. It was not something. Therefore, when the conductive adhesive material is required to have chemical durability, a noble metal powder such as Au, Pd, and Pt or an alloy powder thereof is used as the conductive particles.
[0008]
The present invention has been made to solve the above problems, and has excellent transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance, acid resistance, oxidation resistance, ultraviolet light resistance, and the like. Conductive particles with significantly improved environmental resistance, containing these conductive particles have excellent conductivity, and have significantly improved environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. It has excellent transparency, conductivity, antistatic property and electromagnetic wave shielding property by containing the conductive adhesive material and the above-mentioned conductive particles, as well as environmental resistance such as salt water resistance, acid resistance, oxidation resistance and ultraviolet resistance. A coating for forming a transparent conductive film capable of forming a transparent conductive film that has a remarkably improved property, has excellent adhesion to the substrate, and is also economical. The transparent conductive film obtained by And an object thereof is transparent conductive film to provide a display device, which is formed on the display surface.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following conductive particles, a conductive adhesive material containing the same, a paint for forming a transparent conductive film, a transparent conductive film using the same, and a display device.
That is, the conductive particles of the present invention are characterized in that a coating layer made of an oxide is formed on the surface of metal particles.
In the conductive particles, by forming a coating layer of an oxide on the surface of the metal particles, not only excellent transparency, conductivity, antistatic properties, electromagnetic wave shielding properties, but also salt water resistance, acid resistance, Environmental resistance such as oxidation resistance and ultraviolet resistance is significantly improved.
[0010]
The oxide is silicon oxide (SiO ₂ ), Aluminum oxide (Al ₂ O ₃ ), Titanium oxide (TiO) ₂ ), Zirconium oxide (ZrO) ₂ ), Tin oxide (SnO) ₂ ), Molybdenum oxide (MoO) ₂ , MoO ₃ , Other molybdenum oxides), tungsten oxide (WO ₂ , WO ₃ , Other tungsten oxides), chromium oxide (Cr ₂ O ₃ , CrO ₂ , CrO ₃ , And other chromium oxides).
[0011]
The coating layer preferably contains a second metal.
It is preferable that the second metal is a metal different from the metal particles.
The second metal includes gold (Au), platinum (Pt), palladium (Pd), osmium (Os), iridium (Ir), ruthenium (Ru), rhenium (Re), rhodium (Rh), and silver (Ag). ) And one or more selected from copper (Cu).
It is preferable that the second metal is deposited in voids of the coating layer.
The metal particles preferably contain one or more selected from silver (Ag), copper (Cu), and nickel (Ni).
[0012]
The conductive adhesive material of the present invention is characterized by containing the conductive particles of the present invention.
By containing the conductive particles of the present invention, this conductive adhesive material not only has excellent conductivity, but also has remarkably improved environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. I do.
[0013]
The paint for forming a transparent conductive film of the present invention is characterized by containing the conductive particles of the present invention.
The paint for forming a transparent conductive film contains the conductive particles of the present invention, which not only has excellent transparency, conductivity, antistatic property and electromagnetic wave shielding property, but also has salt water resistance, acid resistance, and oxidation resistance. And environmental resistance such as UV resistance are remarkably improved.
[0014]
In addition, since the conductive particles have a coating layer made of an oxide formed on the surface of the metal particles, a transparent conductive film formed using the coating material for forming a transparent conductive film and a base material such as glass. And the like, there is no possibility that problems such as peeling and scratches may occur during use.
[0015]
The transparent conductive film of the present invention includes a transparent conductive layer formed by applying the transparent conductive film forming paint of the present invention.
It is preferable to form an anti-reflection layer on one or both main surfaces of the transparent conductive layer.
[0016]
In the transparent conductive film of the present invention, by applying the transparent conductive film forming paint of the present invention to form a transparent conductive layer, not only the transparency, conductivity, antistatic properties, and electromagnetic wave shielding properties are excellent, but also Environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance is remarkably improved.
In addition, since the adhesion between the transparent conductive film and a substrate such as glass is improved, there is no possibility that defects such as peeling and scratches may occur during use.
[0017]
The display device of the present invention is characterized in that the transparent conductive film of the present invention is formed on a display surface.
In this display device, since the transparent conductive film of the present invention is formed on the display surface, the display surface is excellent not only in transparency, conductivity, antistatic property, and electromagnetic wave shielding property, but also in salt water resistance and acid resistance. Environmental resistance such as heat resistance, oxidation resistance and ultraviolet light resistance is remarkably improved.
In addition, since the adhesion between the display surface and the transparent conductive film is improved, there is no possibility that defects such as peeling and scratches may occur even during use, and visibility and reliability on the display surface are improved.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the conductive particles of the present invention, a conductive adhesive material containing the same, a paint for forming a transparent conductive film, a transparent conductive film using the same, and a display device will be described. This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified.
[0019]
`` Conductive particles ''
FIG. 1 is a cross-sectional view showing the conductive particles of the present embodiment. In the figure, reference numeral 1 denotes a metal particle serving as a central nucleus, and 2 denotes a coating layer made of an oxide that covers the surface of the metal particle 1. .
The material of the metal particles 1 is not particularly limited, but is excellent in conductivity, low in manufacturing cost, has a high metal ion strength as compared with other metals, and is relatively small in the conductive particles of the present embodiment. Single metal particles of silver (Ag), copper (Cu), nickel (Ni) from the viewpoint that they are inexpensive materials because they are easy to manufacture and are relatively abundant on the earth as resources. Or one or two or more selected from Ag, Cu, and Ni like alloy particles thereof.
[0020]
The particle size of the metal particles 1 is not particularly limited, but when used for a transparent conductive film forming paint from the viewpoint of transparency and conductivity, a particle size of 2 to 100 nm is preferable. A preferred particle size is 2 to 30 nm, and a more preferred particle size is 5 to 30 nm.
The reason for this is that if the particle size is smaller than 2 nm, the dispersibility becomes poor, the transparency of the formed film decreases, and the conductivity also deteriorates. This is because the transparency of the resulting film deteriorates.
Further, when used for a conductive adhesive material, a particle size of 5 nm to 10 μm is preferable, and when transparency is particularly required, a particle size of 5 to 20 nm is preferable.
[0021]
The metal particles 1 may be manufactured by any method. For example, a metal salt is reduced in a solution using a reducing agent such as sodium borohydride, formalin, hydrazine, or alcohol. Colloidal metal fine particles obtained by a so-called liquid phase reduction method are preferably used when used in a paint for forming a transparent conductive film.
[0022]
The material of the oxide constituting the coating layer 2 is not particularly limited, but silicon oxide (SiO 2) having excellent chemical stability is used. ₂ ), Aluminum oxide (Al ₂ O ₃ ), Titanium oxide (TiO) ₂ ), Zirconium oxide (ZrO) ₂ ), Tin oxide (SnO) ₂ ), Molybdenum oxide (MoO) ₂ , MoO ₃ , Other molybdenum oxides), tungsten oxide (WO ₂ , WO ₃ , Other tungsten oxides), chromium oxide (Cr ₂ O ₃ , CrO ₂ , CrO ₃ , And other chromium oxides).
These oxides are more excellent in chemical resistance such as salt water resistance, acid resistance, oxidation resistance and the like, corrosion resistance and heat resistance than metals, and are also excellent in heat resistance. A sufficient effect for improving the environmental resistance of the metal particles 1 can be exhibited.
[0023]
The coating layer 2 preferably contains a second metal, and the second metal is preferably a metal different from the metal particles 1. Here, containing a metal does not mean a state in which a metal element is included as a metal compound, but means that a metal exists alone. The phrase “the coating layer 2 contains the second metal” refers to a state in which the coating layer 2 has the second metal in one or both of the inside and the surface of the coating layer 2. May be in the form of particles, a continuous thin line like a whisker, or a two-dimensionally connected film.
[0024]
The thickness of the coating layer 2 is not particularly limited, but is preferably 0.2 to 100 nm. The reason is that if the thickness is smaller than 0.2 nm, contact between the metal particles 1 serving as the central nucleus and a gas such as an oxidizing gas, a corrosive gas, water vapor, or salt water, which deteriorates the conductivity of the metal particles 1. If the thickness is more than 100 nm, the metal particles 1 serving as the central nucleus have resistance to salt water, acid, oxidation, and ultraviolet. The environmental property does not further increase, and the connection distance between the second metal existing in one or both of the inside and the surface of the coating layer 2 and the metal particle 1 serving as the central nucleus increases, and This is because, since the oxide is insulative, the conductivity of the coating layer 2 decreases, and it becomes difficult to obtain the required electric conductivity.
[0025]
The preferable thickness of the coating layer 2 is preferably 0.2 to 50 nm, more preferably 1 to 50 nm, particularly in the case where the coating layer 2 is used for a paint for forming a transparent conductive film, in view of the relationship with the particle size of the metal particles 1 serving as the central nucleus. ５０50 nm, more preferably 2-20 nm. The type of the second metal is not particularly limited, but it is desirable to select a metal type having excellent oxidation resistance and chemical resistance. For example, Au, Pt, Pd, Os, Ir, Ru, Re, Rh and the like are preferably exemplified. Further, as the metal contained in the chemically stable oxide coating layer 2, Ag and Cu can be used in addition to the above-mentioned noble metals.
This second metal is preferably precipitated in the voids of the coating layer 2.
[0026]
FIG. 2 is a schematic diagram showing an example of the cross-sectional structure of the coating layer 2, in which the state of the second metal is a particle. The coating layer 2 is composed of an oxide layer 3 constituting a main part thereof, and second metal particles 4 precipitated in voids of the oxide layer 3.
There is no particular limitation on the particle diameter of the second metal particles 4, but the particle diameter of the second metal particles 4 present inside the oxide layer 3 is preferably 0.1 nm to 10 nm. The particle diameter of the second metal particles 4 present on the surface of the material layer 3 is preferably 0.1 nm to 10 nm.
[0027]
The amount of the second metal particles 4 present in one or both of the inside and the surface of the coating layer 2 is not particularly limited,
(Equation 1)

Is a preferred range.
[0028]
Here, the reason why the amount of the second metal particles 4 is limited to 2 to 30% by weight is that if the amount is less than 2% by weight, either one of the inside or the surface of the coating layer 2 or one of the two This is because the conductivity between the second metal particles 4 present in the portion and the metal particles 1 serving as the central nucleus is poor, and it is difficult to obtain good conductivity. This is because, even if it is added more than that, further improvement effects such as conductivity, oxidation resistance and chemical resistance cannot be expected.
[0029]
The conductive particles of the present embodiment have excellent environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance by having the above-described structure. When the coating layer 2 made of an oxide contains the second metal particles 4, the conductivity of the conductive particles depends on the metal particles 1 serving as a central nucleus and either the inside or the surface of the coating layer 2. Alternatively, it is obtained by the flow of electricity between the second metal particles 4 present in a part of both, but the metal particles 1 contribute much more to the conductivity. The obtained conductivity is mainly carried by the metal particles 1.
[0030]
Further, the coating layer 2 suppresses contact between the metal particles 1 and a corrosive gas such as an acidic gas or an alkaline gas, water vapor that induces electromigration, or oxygen that oxidizes a metal.
The second metal particles 4 present in one or both of the inside of the coating layer 2 and the surface thereof cover the voids having a molecular size of several tens of nanometers existing in the oxide layer 3 to thereby oxidize. Contact between the corrosive gas, corrosive gas or water vapor and the metal particles 1 serving as the central nucleus is further suppressed, and at the same time, conduction with the metal particles 1 is ensured.
[0031]
As shown in FIG. 3, when the voids existing in the oxide layer 3 constituting the coating layer 5 extend from the surface of the oxide layer 3 to the surface of the metal particles 1, the second metal particles 4 Is preferably precipitated from the surface of the oxide layer 3 to the surface of the metal particles 1. When the second metal particles 4 precipitate in this manner, a corrosive gas such as an oxidizing gas, an acid gas, or an alkaline gas, or a gas such as water vapor that induces electromigration and the metal particles 1 serving as a central nucleus are formed. Contact can be further suppressed. Further, since the metal particles 1 are in contact with the second metal particles 4, excellent conductivity is obtained.
[0032]
Next, a method for producing the conductive particles of the present embodiment will be described.
In order to form the coating layer 2 made of an oxide on the surface of the metal particles 1 serving as a central nucleus, the metal particles or colloidal metal particles are coated with a silane such as aminosilane, mercaptosilane, glycidoxysilane, methacryloxysilane or the like. The surface is modified using a coupling agent, and then immersed in an alkali silicate solution such as sodium silicate or a metal alkoxide solution to form a coating layer 2 on the surface of the metal particles 1.
[0033]
As the above silane coupling agent,
γ-aminopropyltriethoxysilane,
N- (β-aminoethyl) -γ-aminopropylmethoxysilane,
N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane,
γ-mercaptopropyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropylmethyldimethoxysilane,
γ-methacryloxypropyltrimethoxysilane,
γ-methacryloxypropyldimethoxysilane and the like can be exemplified.
[0034]
Examples of the metal alkoxide include silicon methoxide, silicon ethoxide, silicon alkoxide such as silicon propoxide, aluminum alkoxide such as aluminum propoxide, titanium alkoxide such as titanium propoxide and titanium butoxide, zirconium propoxide, and zirconium. Examples include zirconium alkoxides such as butoxide, tin alkoxides such as tin propoxide, and tin butoxide.
[0035]
When the surface of the metal particle 1 is modified using the above silane coupling agent, an alkali silicate or a metal alkoxide is added onto a silanol group (—SiOH) of the coupling agent on the surface of the metal particle 1 serving as a central nucleus. The coating layer 2 made of an oxide is formed on the surface of the metal particles 1 by performing a hydrolysis reaction or a condensation polymerization reaction. The thickness of the coating layer 2 can be controlled to a desired thickness by controlling the temperature of the solution when forming the coating layer 2 and the immersion time.
[0036]
Furthermore, in order to deposit the metal particles 4 on one or both of the inside and the surface of the coating layer 2, the metal particles on which the above-described coating layer has been formed have a smaller ionization tendency than the metal particles serving as the central nucleus. Immersion or contact in a metal salt solution such as hydrochloride, nitrate, acetate, sulfite or an organic acid metal salt solution such as lactate, citrate, etc., and either or both of the inside and the surface of the coating layer 2 Then, the second metal particles 4 are precipitated.
[0037]
In this case, due to the difference between the ionization tendency of the metal particles 1 serving as the central nucleus and the ionization tendency of the metal ions in the metal salt, the metal as a component of the metal particles 1 is oxidized and eluted into the metal salt solution as metal ions. At the same time, the metal ions in the metal salt solution are reduced and become metal particles, and are deposited on one or both of the inside and the surface of the coating layer 2. For example, when Ag particles are used as the metal particles 1, Au, Pt, Pd, Os, Ir, Ru, Re, Rh, and the like can be used as the metal species of the metal salt to be used. In particular, Au, Pt, Pd , Ru are preferred.
[0038]
As for the metal species of these metal salts, the same precipitation reaction as described above occurs even if a metal salt solution in which a plurality of metal species coexist is used. Therefore, by using a metal salt solution in which a plurality of metal species coexist, one or both of the inside and the surface of the coating layer 2 is made of alloy particles or a plurality of types of alloy particles different from the metal particles 1 serving as a central nucleus. It is possible to produce conductive particles including metal particles.
[0039]
In addition, instead of the above-described metal salt solution, a precipitation reaction similar to the above occurs even when an organic acid metal salt solution such as lactate or citrate in which a plurality of metal species coexist is used.
The amount of the metal to be deposited can be controlled by controlling the amount of metal ions present in the above-mentioned metal salt solution or organic acid metal salt solution.
As described above, the conductive particles of the present embodiment can be manufactured.
[0040]
The conductive particles obtained in this manner show no change in electrical conductivity even when they are brought into contact with a deterioration factor such as salt water, acidic or oxidizing liquid or gas for a long period of time. By using the conductive particles, the antistatic property or the electromagnetic wave shielding property of the obtained transparent conductive film can be maintained for a long period of time. Each of these conductive particles has an electric conductivity of 10 ^-5 Ωcm or less, and the surface resistance when a transparent conductive film containing these conductive particles is formed is 10 ^-1 -10 ³ Since Ω / □, practically sufficient electromagnetic wave shielding performance can be obtained.
[0041]
In the conductive particles of the present embodiment, since the coating layer 2 made of an oxide is formed on the surface of the metal particles 1 serving as the central nucleus, the conductive layer formed using the conductive particles has a film strength. It is significantly improved, and the scratch strength is improved. In the case where one or more transparent layers having a refractive index different from the refractive index of the conductive layer are provided in the upper layer or the lower layer (either main surface) or the upper and lower layers (both main surfaces) of the conductive layer. Has the advantage that the wettability with the silica-based binder component usually used as a transparent layer is good, and the adhesion between both layers is improved, and the scratch strength can be further improved.
[0042]
"Colloidal dispersion"
By subjecting the conductive particles to a normal washing method such as electrodialysis, a colloidal dispersion can be obtained. In particular, since the colloidal dispersion using the conductive particles of the present embodiment is a dispersion system using an electric double layer of a coating layer formed of an oxide formed on the surface of metal particles serving as a central nucleus, a conventional metal is used. A dispersion having extremely high stability as compared with a colloid and a high concentration of conductive particles can be obtained.
[0043]
`` Paint for forming transparent conductive film ''
By adding the above-mentioned colloidal dispersion to a solvent, the paint for forming a transparent conductive film of the present embodiment can be obtained.
Examples of the solvent include water and an organic solvent. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol, and butanol, β-oxyethyl methyl ether (methyl cellosolve), and β-oxyethyl ether (ethyl cellosolve). ), Butyl-β-oxyethyl ether (butyl cellosolve) and the like, phenols, esters, ketones, glycols, aromatic compounds and the like.
[0044]
This transparent conductive film forming paint, in addition to the conductive particles described above, for adjusting the color tone of the transmitted light of the transparent conductive film, as a coloring agent, a dye, an organic pigment, or metal fine particles having high chemical stability. A trace amount may be contained.
The coloring material may be added to any of the layers constituting the transparent conductive film. For example, when the coloring material is added to the transparent conductive layer, the added amount is 20% by weight or less based on the content of the metal particles, particularly It is preferable that the content be 10% by weight or less.
The reason is that if the addition amount exceeds 20% by weight, the conductivity and the film strength are reduced, and the electromagnetic wave shielding effect is hindered.
[0045]
Examples of the coloring material include monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, thioindigo bordeaux, Organic pigments such as perylene orange, perylene scarlet, perylene red 178, perylylene maroon, dioxazine violet, isoindoline yellow, nickel nitroso yellow, madder lake, copper azomethine yellow, aniline black, and alkali blue are preferably used.
[0046]
In addition, zinc white, titanium oxide, red iron oxide, chrome oxide, iron black, titanium erotic, cobalt blue, cerulean blue, cobalt green, alumina white, viridian, cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange Also, inorganic pigments such as zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white, ultramarine, manganese violet, emerald green, navy blue, and carbon black are preferably used.
[0047]
Further, various dyes such as azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, and perinone dyes are also suitable. Used for
These coloring materials can be used alone or in combination of two or more.
[0048]
Further, in addition to the various components described above, the transparent conductive film forming paint may further include other components such as silicon (Si), aluminum (Al), and zirconium (if necessary) for the purpose of improving film strength and conductivity. Oxidation of Zr), cerium (Ce), titanium (Ti), yttrium (Y), zinc (Zn), magnesium (Mg), indium (In), tin (Sn), antimony (Sb), gallium (Ga), etc. Or a composite oxide, a nitride, or the like. In particular, an oxide of indium (In) or tin (Sn), a composite oxide, or inorganic fine particles mainly containing a nitride, etc. May be contained.
[0049]
Also, organic synthetic resins such as polyester resin, acrylic resin, epoxy resin, melamine resin, urethane resin, butyral resin, and ultraviolet curable resin, hydrolysates of metal alkoxides such as silicon, titanium, and zirconium, or silicone monomers and silicone oligomers And organic and inorganic binder components.
Examples of the hydrolytic polycondensable organic silicon compound as a silicon-containing binder include an alkoxysilane represented by the following formula (1).
R <sub>a</sub> Si (OR ') <sub>4-a</sub> ...... (1)
(Wherein, R is a vinyl group, an aryl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom or a halogen atom, and R ′ is a vinyl group, an aryl group, an acryl group, a number of carbon atoms. 1 to 8 alkyl groups, -C <sub>2</sub> H <sub>4</sub> O <sub>n</sub> H <sub>2n + 1</sub> (N = 1 to 4) or a hydrogen atom, and a is 0 or an integer of 1 to 3.)
[0050]
"Transparent conductive film"
The transparent conductive film of this embodiment can be obtained by applying the above-mentioned paint for forming a transparent conductive film to the surface of a substrate such as a glass substrate, a heat-resistant transparent resin, or a glass plate.
Known application techniques such as spin coating, spray coating, dip coating, roll coating, bar coating, and gravure printing can be used as the coating method.
Among these, spin coating, spray coating, and dip coating are each a particularly preferable coating method because a film having a uniform thickness can be formed in a short time.
[0051]
After the application, the applied film is dried and baked if necessary, whereby a transparent conductive layer can be formed on the surface of the substrate.
At the time of coating, it is preferable to set the coating amount so that the thickness of the formed transparent conductive layer is 5 nm to 100 nm. Further, it is preferable that the thickness of the formed transparent conductive layer be 10 nm to 50 nm.
[0052]
The reason is that if the film thickness is less than 5 nm, not only is it difficult to obtain a sufficient electromagnetic wave shielding effect, but also it becomes difficult to form a uniform film due to uneven appearance and the like, while the film thickness exceeds 100 nm. This is because, although there is no problem in conductivity, the light transmittance of the transparent conductive layer is remarkably reduced, so that practical transparency cannot be obtained. Here, the practical transparency means that the total light transmittance is about 40% or more.
[0053]
FIG. 4 is a cross-sectional view showing the transparent conductive film of the present embodiment. In the figure, reference numeral 11 denotes a transparent glass substrate as a base material, and 12 denotes a transparent conductive film forming paint of the present embodiment on the glass substrate 11. The transparent conductive layer of the present embodiment is formed by the transparent conductive layer 12.
[0054]
The transparent conductive layer 12 contains conductive particles in which a coating layer 2 made of an oxide having excellent environmental resistance or an oxide containing a metal is formed on the surface of metal particles 1 serving as a central nucleus. In addition, the film strength is remarkably improved, and the scratch strength is improved.
In addition, since the coating layer 2 made of an oxide or an oxide containing a metal is formed on the surface of the metal particles 1, it is resistant to atmospheres such as halogen, acid, oxidizing, and ultraviolet rays. Even if the metal particles are exposed for a long period of time, there is no danger that the conductivity, the discoloration, the film strength and the like due to the deterioration of the metal particles will occur.
Furthermore, since the coating layer 2 made of an oxide or an oxide containing a metal is formed on the surface of the metal particles 1, the adhesion to the substrate is excellent.
[0055]
The transparent conductive film of the present embodiment can be used on, for example, a display surface of a display panel of various display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, and a cathode ray tube (CRT). Can be applied.
In addition, the present invention can be applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens.
[0056]
According to the above-mentioned display device and various window materials, halogen salts such as salt water produced by seawater during transportation by sea or sweat of operators, hydrogen sulfide gas in hot springs, etc., and SO in the atmosphere <sub>x</sub> High resistance to gas, acid liquid such as acid rain, oxidizing gas such as ozone generated by acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0057]
In the transparent conductive film of the present embodiment, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance is remarkably improved.
In addition, since the adhesion between the transparent conductive film and a substrate such as glass is improved, there is no possibility that defects such as peeling and scratches may occur during use.
Further, in the above display device, since the transparent conductive film of the present embodiment is formed on the display surface, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance on the display surface is significantly improved. .
In addition, since the adhesion between the display surface and the transparent conductive film is improved, there is no possibility that defects such as peeling and scratches may occur even during use, and visibility and reliability on the display surface are improved.
[0058]
"Low reflection transparent conductive film"
The low reflection transparent conductive film of the present embodiment will be described.
This low-reflection transparent conductive film has a refractive index different from the refractive index of the transparent conductive layer in the upper or lower layer (either main surface) or the upper and lower layers (both main surfaces) of the transparent conductive layer. One or more transparent antireflection layers are formed. This antireflection layer is used for removing or reducing external light reflection at the interface of the film by an interference effect.
[0059]
FIG. 5 is a cross-sectional view illustrating the low-reflection transparent conductive film of the present embodiment. A transparent antireflection layer 21 having a refractive index different from that of the transparent conductive layer 12 is provided on the transparent conductive layer 12. The antireflection layer 21 and the transparent conductive layer 12 form a low-reflection transparent conductive film 22.
[0060]
The layer configuration of the low-reflection transparent conductive film 22 is not limited to the above-described configuration. For example, as shown in FIG. 6, the low-reflection transparent conductive film 22 has a configuration in which the anti-reflection layer 21 is formed below the transparent conductive layer 12. The conductive film 31 may be used. Further, as shown in FIG. 7, a low-reflection transparent conductive film 41 having a configuration in which the antireflection layer 21 is formed in an upper layer and a lower layer so as to sandwich the transparent conductive layer 12 may be used. Further, the anti-reflection layer 21 may be a single layer or two or more layers.
[0061]
The refractive index of the antireflection layer 21 is desirably 1.60 or less. The anti-reflection layer 21 is expected to not only prevent the reflection of external light and to improve the visibility of the display device but also to protect the low-reflection transparent conductive films 22 and 41 from external force. In addition, it is necessary to have sufficient mechanical strength.
[0062]
Examples of the coating agent for forming the anti-reflection layer 21 include thermoplastic resins such as polyester resin, acrylic resin, epoxy resin, and butyral resin, thermosetting resins, or photo / electron beam curable resins, silicon, aluminum, Examples include coating solutions containing one or more components selected from hydrolysates of metal alkoxides such as zirconium and titanium, and silicone monomers or silicone oligomers. The above components can be used alone or as a mixture.
[0063]
Similar to the formation of the transparent conductive layer 12, the antireflection layer 21 is formed by uniformly applying a coating solution containing one or more components described above, that is, an antireflection paint on a predetermined surface. It can be done by a method. As a coating method, a spin coating method, a roll coating method, a spray coating method, a dip coating method, a bar coating method, a gravure printing method, or the like is suitably used.
After the application, the applied film is dried, and preferably a strong film is formed by baking or irradiating light and electron beams.
[0064]
The low-reflection transparent conductive films 22, 31, and 41 of the present embodiment are, for example, a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, and a cathode ray tube, similarly to the above-described transparent conductive films. (CRT) and the like can be applied to the display surface of the display panel of various display devices.
In addition, the present invention can be applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens.
[0065]
"Display device"
FIG. 8 is a cross-sectional view illustrating a display surface of the display device according to the present embodiment, and is an example of a display surface of a plasma display panel (PDP). The display surface of this PDP has a configuration in which the low-reflection transparent conductive film 22 is formed on the front surface of a display panel 51 made of a transparent glass substrate.
[0066]
Since the transparent conductive layer 12 contains the conductive particles of the present embodiment, the low-reflection transparent conductive film 22 has sufficient conductivity to exhibit electromagnetic wave shielding properties. The transmittance of the transparent conductive layer 12 is adjusted within a range of 100 nm or less in order to adjust the contrast of the transmission image of the display device. In addition, since the anti-reflection layer 21 having a refractive index different from that of the transparent conductive layer 12 is formed on the low-reflection transparent conductive film 22, reflection of external light is prevented.
[0067]
In addition, since the conductive particles contained in the transparent conductive layer 12 are the conductive particles of the present embodiment, the low-reflection transparent conductive film 22 is resistant to an atmosphere such as halogen, acid, oxidizing, and ultraviolet. Therefore, even if the conductive particles are exposed to these atmospheres for a long period of time, there is no possibility of causing a decrease in conductivity, discoloration, a decrease in film strength, and the like due to deterioration of the conductive particles. Further, the conductive particles constituting the transparent conductive layer 12 have excellent adhesion to the display panel 51 as a base material since the coating layer 2 made of an oxide is formed on the surface of the metal particles 1.
[0068]
In the present embodiment, the display device in which the low-reflection transparent conductive film 22 is formed on the front surface of the display panel 51 is described as an example, but the low-reflection transparent conductive films 31 and 41 are formed instead of the low-reflection transparent conductive film 22. It may be configured.
[0069]
According to the display device of the present embodiment, since the low-reflection transparent conductive film 22 is formed on the front surface of the display panel 51, the low-reflection transparent conductive film 22 can shield electromagnetic waves radiated from the display device. Electromagnetic wave interference can be prevented.
Further, since the low-reflection transparent conductive film 22 has excellent light transmittance, the image becomes bright. Further, since the reflection of external light is reduced, the visibility on the display surface is improved.
Further, since the antireflection layer 21 has good wettability with the transparent conductive layer 12, the adhesion between both the antireflection layer 21 and the transparent conductive layer 12 can be improved, and the scratch strength can be further improved. Can be.
[0070]
Further, similarly to the case where the transparent conductive film is formed, a halogen salt such as salt brought from seawater during transportation by sea or an operator's sweat, a hydrogen sulfide gas in a hot spring area or the like, and a sulfur dioxide in the atmosphere are also used. <sub>x</sub> High resistance to gas, acid liquid such as acid rain, oxidizing gas such as ozone generated by acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0071]
The low-reflection transparent conductive films 22, 31, and 41 formed on the display panel 51 are applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens. be able to.
In these various window materials, similarly to the case where the above-described transparent conductive film is formed, halogen salts such as salt brought by seawater during transportation by sea or sweat of an operator, hydrogen sulfide gas in hot springs, and air SO in <sub>X</sub> High resistance to gas, acid liquid such as acid rain, oxidizing gas such as ozone generated by acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0072]
`` Specific examples of conductive particles ''
Hereinafter, as a specific example of the conductive particles of the present embodiment, a case where the oxide that is a component of the coating layer is silica (silicon dioxide) will be described.
The conductive particles form a coating layer (hereinafter also referred to as a silica layer) made of silica (silicon dioxide) having extremely excellent salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance on the surface of the metal particles. Thereby, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance of the metal particles is remarkably improved.
In addition, by using silica as the main component of the coating layer, when a transparent conductive film is formed using a transparent conductive film forming paint using the conductive particles, adhesion between the transparent conductive film and a substrate such as glass is reduced. Thus, even during use, there is no possibility that defects such as peeling and scratches may occur.
[0073]
As a method for forming a silica layer on the surface of metal particles, a method of mixing metal particles or colloidal metal particles with water glass, an organosilicon compound or the like and reacting the mixture is employed. Thereby, a strong silica layer can be formed on the surface of the metal particle.
It is preferable that the metal particles include one or more selected from Ag, Cu, and Ni.
[0074]
Examples of the organosilicon compound include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, tetramethoxysilane, methyltriethoxysilane, tetraethoxysilane, methyldimethoxysilane, dimethylethoxysilane , Dimethylvinylmethoxysilane, dimethylvinylethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, diphenyldimethoxysilane, phenyltrimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, γ-chloropropyl Trimethoxysilane, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-amino Ropirtriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane , Γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane and the like are preferably used.
[0075]
Even if the silica-coated metal particles are brought into contact with a deterioration factor such as salt water, an acidic or oxidizing liquid or gas for a long period of time, no change in conductivity is observed. Therefore, if a coating for forming a transparent conductive film is prepared using the silica-coated metal particles, the resulting transparent conductive film can maintain its antistatic property or electromagnetic wave shielding property for a long period of time.
The conductivity of each of the silica-coated metal particles was 10%. ^-5 Ωcm or less, and the surface resistance after film formation is 10 ^-1 -10 ³ Since the level is Ω / □, practically sufficient electromagnetic wave shielding performance can be obtained.
[0076]
It is preferable that the silica layer further contains a noble metal because conductivity is improved. Further, it is preferable that this noble metal is precipitated in the voids of the silica layer.
Examples of the noble metal include Au, Pt, Pd, Os, Ir, Ru, Re, Rh and the like. In particular, one or more kinds selected from Au, Pt, Pd, Rh, and Ru may be used. preferable.
[0077]
The surface-coated metal particles whose surfaces are coated with the silica layer containing the noble metal can be obtained by depositing the above-mentioned noble metal in the voids of the silica layer.
Here, in order to deposit the noble metal in the voids of the silica layer, the above-mentioned silica-coated metal particles are converted into a solution containing one or more metal salts selected from Au, Pt, Pd, Rh, and Ru. The two are brought into contact by immersing or mixing the silica-coated metal particles and the solution.
[0078]
In the silica-coated metal particles, voids are formed in the silica layer formed on the surface, and the voids extend from the surface of the silica layer to the surface of the metal particles. Therefore, if atoms on the outermost surface of the metal particles are ion-exchanged with ions of Au, Pt, Pd, Rh, Ru, or the like, Au, Pt, Pd, Rh, Ru and the like can be precipitated, and surface-coated metal particles whose surface is coated with a noble metal-containing silica layer can be easily obtained.
The surface-coated metal particles thus obtained exhibit excellent conductivity because the noble metal is precipitated from the surface of the silica layer to the surface of the internal metal particles.
[0079]
As described above, surface-coated metal particles coated with the silica layer containing the noble metal can be obtained. Since the noble metal is one or more selected from Au, Pt, Pd, Rh, and Ru, Au, Pt, Pd, Rh, Ru, and the like are present in the voids of the silica layer. Through the above, excellent conductivity can be exhibited.
[0080]
By subjecting the silica-coated metal particles or the surface-coated metal particles to a normal washing method such as electrodialysis, a colloidal dispersion can be obtained.
Since the above-mentioned silica-coated metal particles or surface-coated metal particles are a dispersion system in which an electric double layer of silica formed on the particle surface is used, the stability is extremely high as compared with a conventional metal colloid, and the concentration of the metal particles is high. And a dispersion having a high value can be obtained.
[0081]
By adding the thus obtained colloidal dispersion to a solvent, it is possible to obtain a paint for forming a transparent conductive film containing silica-coated metal particles or surface-coated metal particles as a main component. Examples of the solvent include water and an organic solvent. Examples of the hydrophilic organic solvent include alcohols such as methanol, ethanol, propanol, and butanol, β-oxyethyl methyl ether (methyl cellosolve), and β-oxyethyl. Ethers such as ether (ethyl cellosolve) and butyl-β-oxyethyl ether (butyl cellosolve) can be used.
[0082]
The transparent conductive film can be obtained by applying the transparent conductive film forming paint to the surface of a substrate such as a glass substrate, a heat-resistant transparent resin, or a glass plate.
In the transparent conductive film formed in this way, a silica layer having excellent environmental resistance or a silica layer containing a noble metal is formed on the surface of the metal particles, so that the film strength is significantly improved and the scratch strength is improved. I do.
[0083]
In addition, since a silica layer having excellent environmental resistance or a silica layer containing a noble metal is formed on the surface of the metal particles, it is resistant to atmospheres such as halogen, acid, oxidization, and ultraviolet light. , There is no danger of causing a decrease in conductivity, discoloration, a decrease in film strength, and the like due to deterioration of the metal particles.
Furthermore, since a silica layer or a silica layer containing a noble metal is formed on the surface of the metal particles, the adhesion to the substrate is excellent.
[0084]
This transparent conductive film can be applied to, for example, display panels of various display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, and a cathode ray tube (CRT).
In addition, the present invention can be applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens.
[0085]
According to the above-mentioned display device and various window materials, halogen salts such as salt water produced by seawater during transportation by sea or sweat of operators, hydrogen sulfide gas in hot springs, etc., and SO in the atmosphere _x High resistance to gas, acid liquid such as acid rain, oxidizing gas such as ozone generated by acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0086]
`` Conductive adhesive material ''
Hereinafter, the conductive adhesive material of the present embodiment will be described.
The conductive adhesive material of the present embodiment is characterized by containing the conductive particles of the present embodiment, and the conductive adhesive material has the following four types.
(1) A conductive adhesive material A comprising the conductive particles of the present embodiment and a solvent
(2) The conductive adhesive material B comprising the conductive particles of the present embodiment and a binder
(3) The conductive adhesive material C comprising the conductive particles, the solvent, and the binder of the present embodiment
(4) A conductive adhesive material D in which any of the above (1) to (3) is fixed on a substrate
[0087]
Next, each of the conductive adhesive materials A to D will be described.
"Conductive adhesive material A"
The conductive adhesive material is obtained by using the conductive particles of the present embodiment by using a surfactant such as an anionic type, a cationic type, or a polymer type to form water, alcohols, phenols, esters, ketones, and ethers. And a known solvent such as an aromatic compound.
[0088]
Examples of known solvents include alcohols such as methanol, ethanol, propanol, and butanol. Examples of phenols include terpineol. Examples of the esters include ethyl acetate and butyl acetate. Ketones include methyl ethyl ketone and methyl isobutyl ketone.
[0089]
As ethers, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol-n-exyl ether and their acetates, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisobutyl ether , Diethylene glycol monohexyl ether and their acetates, triethylene glycol monoalkyl and their acetates.
Other solvents include dioxane, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, lactone and the like.
The solvent preferably contains at least one kind or two or more kinds.
[0090]
"Conductive adhesive material B"
This conductive adhesive material, the conductive particles of the present embodiment, a thermoplastic resin as a binder, a thermosetting resin, an electron beam curable resin, an organic binder made of an organic resin such as a pressure-sensitive resin, polysilane, metal alkoxide It is a conductive adhesive material mixed with an organic metal binder such as a condensation polymer and an inorganic binder such as glass frit.
[0091]
As organic binders, ethyl cellulose, hydroxyethyl cellulose, methyl cellulose, nitrocellulose, ethyl cellulose derivatives, polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, acrylic resin, butyral resin, phenolic resin, polyurethane resin, polyester resin, alkyd resin, acetic acid It can be selected from vinyl resins, ethylene-vinyl acetate copolymers, styrene resins, epoxy resins, amino resins, polyimide resins, melamine alkyd resins, resole resins, and modified resins thereof.
[0092]
"Conductive adhesive material C"
This conductive adhesive material is a conductive adhesive material obtained by mixing the conductive particles of the present embodiment, the solvent used for the conductive adhesive material A, and the binder used for the conductive adhesive material B.
[0093]
"Conductive adhesive material D"
This conductive adhesive material is a conductive adhesive material formed by applying the conductive adhesive material of the above-described conductive adhesive materials A to C on a base material such as a plastic film, a plastic plate, a metal plate, and a glass plate. is there.
[0094]
Various known additives may be added to these conductive adhesive materials A to D as necessary. For example, a known viscosity adjuster, diluent, suspending agent, leveling agent, defoaming agent and the like may be added.
[0095]
The substrate to which the conductive adhesive materials A to D can be applied is not particularly limited, and examples thereof include the following substrates.
Glass substrate, metal substrate such as aluminum and stainless steel, ceramic substrate such as alumina and aluminum nitride, semiconductor substrate such as silicon wafer and gallium arsenide wafer, glass epoxy resin substrate, paper phenol resin substrate, polyimide substrate, polyester resin substrate, BT Flexible substrates such as a resin substrate, a polysulfone resin substrate, a polyethersulfone resin substrate, a polyetherimide resin substrate, a polybutadiene resin substrate, and a glass polyimide resin substrate, a resin substrate, and the like can be given.
[0096]
Since the conductive adhesive material of the present embodiment contains the conductive particles of the present embodiment, it is possible to provide a conductive adhesive material that does not cause conductive failure due to oxidation or corrosion of the conductive particles. .
Further, this conductive adhesive material can be used for electrode formation, circuit wiring formation, conductive bonding, conductive film formation, etc. of various electronic devices and the like. Electronic devices and the like manufactured using this conductive adhesive material include halogen salts such as salt, hydrogen sulfide gas in hot springs, etc., and SO 2 in the atmosphere. _x Extremely few troubles such as poor electrical conductivity even when used in harsh environments containing deterioration factors such as gas, acid liquid such as acid rain, acid gas, and oxidizing gas such as ozone generated by ultraviolet rays. .
[0097]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[0098]
[Example 1]
To 100 g of Ag particles having an average particle diameter of 0.1 μm surface-treated with γ-aminopropyltriethoxysilane, 2,000 g of a solution obtained by dissolving 138 g of tetraethoxysilane in ethanol was added, and the mixture was stirred while being kept at 5 ° C. Further, 20 g of 2% aqueous ammonia was added and stirred for 6 hours. Next, this was washed by filtration and then dried at 100 ° C. to obtain silica-coated Ag particles having a silica layer formed on the surface of the Ag particles.
[0099]
Observation of the silica-coated Ag particles using a transmission electron microscope (TEM) revealed that a silica layer of about 20 nm was formed on the surface of the Ag particles. Further, elemental analysis of the silica-coated Ag particles revealed that Si / Ag = 0.027 (weight ratio).
[0100]
Next, 50 g of the silica-coated Ag particles was added to a chloroauric acid solution whose Au concentration was adjusted so that Au / Ag = 0.10 (weight ratio), and the mixture was stirred at 30 ° C. for 2 hours, and the inside of the silica layer was stirred. Then, conductive particles having Au particles precipitated on the surface were prepared.
Observation of the conductive particles using a transmission electron microscope (TEM) confirmed that Au particles of about 5 nm were precipitated on the surface of the silica layer. Further, elemental analysis of the conductive particles revealed that Au / Ag was 0.099 (weight ratio).
[0101]
Next, the conductivity and acid resistance of the silica-coated Ag particles were evaluated.
"Conductivity"
300 kg / cm of the above conductive particles ² The green compact was formed under a uniaxial load, and the specific resistance of the green compact was measured. ^-6 Ω · cm.
[0102]
"Acid resistance"
1 g of the above conductive particles was added to 100 g of 1 mol% hydrochloric acid, stirred at 30 ° C. for 24 hours, filtered, washed, and then dried at 100 ° C. to obtain a sample for evaluation.
The evaluation of acid resistance was made into two items: measurement of the specific resistance of the green compact, and identification of the reaction product by powder X-ray diffraction.
When the specific resistance of the evaluation sample after the test was measured according to the above specific resistance measuring method, 8 × 10 ^-6 Ω · cm, and no increase in specific resistance after the test was observed.
In the powder X-ray diffraction chart, only Ag and Au diffraction lines appeared, and no diffraction line of a reaction product such as silver chloride (AgCl) was observed.
[0103]
[Table 1]

[0104]
[Comparative Example 1]
The Ag particles having an average particle size of 0.1 μm used in Example 1 were evaluated for acid resistance in the same manner as in Example 1.
The specific resistance of the Ag particles was 8 × 10 before the test. ^-6 Ω · cm, but 4 × 10 ³ Ω · cm, and the acid resistance test confirmed that the conductivity had deteriorated.
In the powder X-ray diffraction chart, in addition to the Ag diffraction line, a diffraction line of silver chloride (AgCl) as a reaction product was observed.
[0105]
[Table 2]

[0106]
[Example 2]
50 g of the silica-coated Ag particles prepared in Example 1 was added to a palladium acetate solution whose Pd concentration was adjusted so that Pd / Ag = 0.05 (weight ratio), and the mixture was stirred at 30 ° C. for 2 hours. Conductive particles having Pd particles deposited inside and on the surface of the layer were produced.
Observation of the conductive particles using a transmission electron microscope (TEM) confirmed that about 5 nm of Pd particles had precipitated on the surface of the silica layer. Further, elemental analysis of the conductive particles showed that Pd / Ag was 0.051 (weight ratio).
[0107]
The conductive particles were evaluated for acid resistance in the same manner as in Example 1.
When the specific resistance of the conductive particles was measured according to the specific resistance measurement method of Example 1, it was 8 × 10 both before and after the acid resistance test. ^-6 Ω · cm, and no increase in resistivity after the acid resistance test was observed.
In the powder X-ray diffraction chart, only Ag and Pd diffraction lines appeared, and no diffraction line of a reaction product such as silver chloride (AgCl) was observed.
[0108]
[Table 3]

[0109]
[Example 3]
2000 g of a solution of 48.2 g of aluminum butoxide in ethanol was added to 100 g of Cu particles having an average particle size of 0.3 μm and surface-treated with γ-aminopropyltriethoxysilane, and the solution was stirred while being kept at 5 ° C. Further, 20 g of 0.1% aqueous ammonia was added, and the mixture was stirred for 6 hours. Next, this was washed by filtration and then dried at 100 ° C. to obtain alumina-coated Cu particles having an alumina layer formed on the surface of Cu particles.
[0110]
Observation of the alumina-coated Cu particles using a transmission electron microscope (TEM) revealed that an alumina layer of about 20 nm was formed on the surface of the Cu particles. Elemental analysis of the alumina-coated Cu particles revealed that Al / Cu was 0.0073 (weight ratio).
[0111]
Next, 50 g of the alumina-coated Cu particles were added to a chloroplatinic acid solution whose Pt concentration was adjusted so that Pt / Cu = 0.1 (weight ratio), and the mixture was stirred at 30 ° C. for 2 hours. Then, conductive particles (alumina-Pt-coated Cu particles) having Pt particles precipitated on the surface were prepared.
Observation of the conductive particles using a transmission electron microscope (TEM) confirmed that about 5 nm of Pt particles had precipitated on the surface of the alumina layer. Elemental analysis of the conductive particles showed that Pt / Cu was 0.099 (weight ratio).
[0112]
The oxidation resistance of the conductive particles was evaluated.
"Oxidation resistance"
A powder obtained by freeze-drying the produced conductive particles was subjected to a heat treatment at 150 ° C. for 1 hour in the air to prepare a sample for evaluation.
The evaluation of the oxidation resistance was made into two items: measurement of the specific resistance of the green compact, and identification of the reaction product by powder X-ray diffraction.
[0113]
When the specific resistance was measured according to the specific resistance measuring method of Example 1, it was 8 × 10 before the oxidation resistance test. ^-6 Ω · cm, 9 × 10 after test ^-6 Ω · cm, and the increase in resistivity after the oxidation resistance test was slight.
In the powder X-ray diffraction chart, only diffraction lines of Cu and Pt appeared, and no diffraction line of a reaction product such as copper oxide (CuO) was observed.
[0114]
[Table 4]

[0115]
[Comparative Example 2]
The oxidation resistance of the Cu particles having an average particle diameter of 0.3 μm used in Example 3 was evaluated in the same manner as in Example 3.
When the specific resistance was measured according to the method for measuring the specific resistance of Example 1, it was 8 × 10 before the test. ^-6 Ω · cm, but 4 × 10 ^-1 Ω · cm, and it was confirmed that the conductivity was deteriorated by the oxidation resistance test.
In the powder X-ray diffraction chart, a diffraction line of copper oxide (CuO) as a reaction product was observed in addition to the diffraction line of Cu.
[0116]
[Table 5]

[0117]
Next, conductive particles, dispersions thereof, and low-refractive-index paints used in the following Examples and Comparative Examples were produced by the following methods.
"Production of metal particles"
The following two types of solutions were prepared.
(Solution a)
1700 g of silver nitrate was dissolved in 9 kg of water to obtain a solution a.
(Solution b)
40 g of sodium borohydride and 900 g of sodium citrate were dissolved in 50 kg of water to obtain a solution b.
[0118]
Next, while stirring the solution b, the solution a was gradually added to the solution b to prepare a solution containing Ag particles. When the obtained Ag particles were observed with a transmission electron microscope (TEM), the particle size was about 15 nm.
The solution containing the Ag particles was washed by centrifugation to obtain a colloidal Ag particle dispersion A. The concentration of Ag particles in the Ag particle dispersion A was 1.50% by weight.
[0119]
"Preparation of Ag particle dispersion adsorbing surface modifier"
7.5 g of γ-mercaptopropyltrimethoxysilane was dissolved in 400 g of water to obtain a solution c.
Next, the above solution c was added to 10 kg of the above Ag particle dispersion A and stirred to prepare Ag particle dispersion B to which γ-mercaptopropyltrimethoxysilane was adsorbed.
[0120]
"Formation of zirconia layer on Ag particle surface"
The following solution was prepared.
(Solution d)
300 g of zirconium butoxide was dissolved in 2000 g of ethanol to obtain a solution d.
Next, the above solution d was added dropwise to the above Ag particle dispersion B, followed by stirring at 40 ° C. for 5 hours to prepare zirconia-coated Ag particles whose surface was covered with a zirconia layer.
[0121]
When the zirconia-coated Ag particles were observed using a transmission electron microscope (TEM), the thickness of the zirconia layer was approximately 2 nm.
The suspension of the zirconia-coated Ag particles is washed by a centrifugal separation operation, and then the concentration of the zirconia-coated Ag particles is reduced to 15% by weight using an evaporator to prepare a colloidal zirconia-coated Ag particle dispersion C. did.
[0122]
"Formation of Pd-containing zirconia layer on Ag particle surface"
The following solution was prepared.
(Solution e)
41 g of palladium nitrate was dissolved in 1 kg of water to obtain a solution e.
Next, 45 kg of water was added to 3600 g of the zirconia-coated Ag particle dispersion C, and the above solution e was further added and stirred for 2 hours to precipitate Pd in the zirconia layer and part of the surface, and Pd was deposited on the surface of the Ag particles. The zirconia-Pd-coated Ag particles on which the zirconia layer containing was formed were obtained.
[0123]
Observation of the zirconia-Pd-coated Ag particles using a transmission electron microscope (TEM) revealed that Pd particles having a particle size of 1 nm were uniformly deposited in the zirconia layer and on part of the surface. The presence of a zirconia layer containing was confirmed.
Further, when Ag and Pd of the zirconia-Pd-coated Ag particles were analyzed by chemical analysis, Pd / Ag was 0.036 (weight ratio).
Then, after washing by centrifugation, the concentration of the zirconia-Pd-coated Ag particles was concentrated to 15% by weight using an evaporator to obtain a zirconia-Pd-coated Ag particle dispersion D.
[0124]
"Adjustment of low refractive index paint"
80 g of tetraethoxysilane, 80 g of 0.1 N hydrochloric acid, and 9840 g of ethanol were mixed to prepare a low refractive index paint E.
[0125]
"Formation of silica layer on Ag particle surface"
The following solution was prepared.
(Solution f)
Water glass (SiO ₂ 15 g was dissolved in 1 kg of water to obtain a solution f.
Next, the above-mentioned solution f was added to the above-mentioned colloidal Ag particle dispersion liquid A and stirred for 24 hours to produce silica-coated Ag particles whose surface was coated with a silica layer.
[0126]
Observation of the silica-coated Ag particles using a transmission electron microscope (TEM) revealed that the thickness of the silica layer was approximately 5 nm.
The suspension in which the silica-coated Ag particles are suspended is washed by centrifugation, and then the concentration of the silica-coated Ag particles is concentrated to 15% by weight using an evaporator to prepare a colloidal silica-coated Ag particle dispersion F. did.
[0127]
"Formation of Au-containing silica layer on Ag particle surface"
The following solution was prepared.
(Solution g)
Chloroauric acid (H [AuCl ₄ ] ・ 2H ₂ O) 113 g was dissolved in 1 kg of water to obtain a solution g.
Next, 45 kg of water was added to 3600 g of the silica-coated Ag particle dispersion F described above, and the solution g was further added and stirred for 2 hours to deposit Au in the silica layer covering the Ag particles, and the silica containing Au on the surface of the Ag particles. Silica-Au coated Ag particles having a layer formed thereon were obtained.
[0128]
Observation of the silica-Au-coated Ag particles using a transmission electron microscope (TEM) revealed that Au particles having a particle diameter of 1 nm were precipitated in the silica layer and partially on the surface, and contained Au. The presence of a silica layer was confirmed.
Moreover, when Ag and Au of the silica-Au-coated Ag particles were analyzed by chemical analysis, Au / Ag = 0.106 (weight ratio) was obtained.
Then, after washing by centrifugation, the concentration of the silica-Au-coated Ag particles was concentrated to 15% by weight using an evaporator to obtain a silica-Au-coated Ag particle dispersion G.
[0129]
[Example 4]
"Adjustment of paint for forming transparent conductive film"
2g of zirconia-coated Ag particle dispersion C
78g pure water
Butyl cellosolve 10g
Isopropyl alcohol 10g
Were weighed, mixed, and then uniformly dispersed with an ultrasonic disperser to obtain a coating H for forming a transparent conductive film.
[0130]
"Deposition"
The coating material H for forming a transparent conductive film was applied to the surface of a cathode ray tube (CRT) using a spin coater under the conditions of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the low-refractive-index coating material E was applied using a spin coater at 150 rpm for 30 seconds, and then baked at a temperature of 150 ° C. for 1 hour in a drier to prevent reflection. A cathode ray tube having a transparent conductive film provided (low-reflection transparent conductive film) was obtained.
[0131]
[Example 5]
"Adjustment of paint for forming transparent conductive film"
2 g of zirconia-Pd-coated Ag particle dispersion D
78g pure water
Butyl cellosolve 10g
Isopropyl alcohol 10g
Were weighed, mixed, and then uniformly dispersed by an ultrasonic disperser to obtain a coating film J for forming a transparent conductive film.
[0132]
"Deposition"
The coating material J for forming a transparent conductive film was applied to the surface of a cathode ray tube (CRT) using a spin coater at 150 rpm for 30 seconds, and then dried to form a transparent conductive layer.
Next, on the transparent conductive layer, the low-refractive-index coating material E was applied using a spin coater at 150 rpm for 30 seconds, and then baked at a temperature of 150 ° C. for 1 hour in a drier to prevent reflection. A cathode ray tube having a transparent conductive film provided (low-reflection transparent conductive film) was obtained.
[0133]
[Example 6]
"Adjustment of paint for forming transparent conductive film"
Silica-coated Ag particle dispersion F 2 g
78g pure water
Butyl cellosolve 10g
Isopropyl alcohol 10g
Were weighed, mixed, and then uniformly dispersed with an ultrasonic disperser to obtain a coating K for forming a transparent conductive film.
[0134]
"Deposition"
The paint K for forming a transparent conductive film was applied to the surface of a cathode ray tube (CRT) using a spin coater under the conditions of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the low-refractive-index coating material E was applied using a spin coater at 150 rpm for 30 seconds, and then baked at a temperature of 150 ° C. for 1 hour in a drier to prevent reflection. A cathode ray tube having a transparent conductive film provided (low-reflection transparent conductive film) was obtained.
[0135]
[Example 7]
"Adjustment of paint for forming transparent conductive film"
Silica-Au coated Ag particle dispersion G 2 g
78g pure water
Butyl cellosolve 10g
10 g of isopropyl alcohol
Were weighed, mixed, and then uniformly dispersed with an ultrasonic disperser to obtain a coating L for forming a transparent conductive film.
[0136]
"Deposition"
This coating L for forming a transparent conductive film was applied to the surface of a cathode ray tube (CRT) using a spin coater under the condition of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the low-refractive-index coating material E was applied using a spin coater at 150 rpm for 30 seconds, and then baked at a temperature of 150 ° C. for 1 hour in a drier to prevent reflection. A cathode ray tube having a transparent conductive film provided (low-reflection transparent conductive film) was obtained.
[0137]
[Comparative Example 3]
"Adjustment of paint for forming transparent conductive film"
Ag particle dispersion A 20g
60g pure water
Butyl cellosolve 10g
Isopropyl alcohol 10g
Were weighed, mixed, and then uniformly dispersed with an ultrasonic disperser to obtain a coating film M for forming a transparent conductive film.
[0138]
"Deposition"
The coating material M for forming a transparent conductive film was applied to the surface of a cathode ray tube (CRT) using a spin coater at 150 rpm for 30 seconds, and then dried to form a transparent conductive layer.
Next, on the transparent conductive layer, the low-refractive-index coating material E was applied using a spin coater at 150 rpm for 30 seconds, and then baked at a temperature of 150 ° C. for 1 hour in a drier to prevent reflection. A cathode ray tube having a transparent conductive film provided (low-reflection transparent conductive film) was obtained.
[0139]
"Evaluation"
Surface resistance, reflectance, transmittance, abrasion resistance, and HCl (hydrochloric acid) resistance of the transparent conductive films with antireflection functions (low-reflection transparent conductive films) of Examples 4 to 7 and Comparative Example 3 obtained as described above. , NaCl (salt water) resistance, H resistance ₂ O ₂ (Hydrogen peroxide) properties and paint stability were evaluated using the following method and apparatus.
[0140]

[0141]

[0142]

Tables 6 to 9 show the evaluation results of Examples 4 to 7 and Comparative Example 3.
[0143]
[Table 6]

[0144]
[Table 7]

[0145]
[Table 8]

[0146]
[Table 9]

[0147]
According to the results in Tables 6 to 9, in Examples 4 to 7, good results were obtained in all evaluation items, and not only excellent in transparency, conductivity, antistatic property and the like, but also in resistance. HCl resistance, NaCl resistance, H resistance ₂ O ₂ It was confirmed that environmental resistance such as resistance and scratch resistance were good. It was also confirmed that the coating stability was good.
[0148]
On the other hand, in Comparative Example 3, although the transparency, conductivity, antistatic property and the like are not inferior to those of Examples 4 to 7, the film is peeled in the HCl resistance and the NaCl resistance, and the surface resistance is measured. I couldn't. In addition, H resistance ₂ O ₂ Regarding the properties, although no change in appearance was observed, the rate of change in surface resistance exceeded 1000%, indicating that the layer was changed to a high-resistance layer or an insulating layer. In addition, a precipitate was generated in the paint stability, and deterioration of the paint was recognized.
[0149]
Example 8
To 200 g of the conductive particles (silica-Au-coated Ag particles) obtained in Example 1, 4 g of sebacic acid, 2 g of triethanolamine, 80 g of butyl cellosolve, and 20 g of resole resin were added, and preliminarily mixed with a planetary mill. The mixture was kneaded with this roll mill to produce a conductive adhesive material. Next, using this conductive adhesive material, a 200 μm-wide line and a 40 μm space test pattern were printed on a BT resin substrate with a screen printer, and then dried and cured at 160 ° C. to form a conductive wire pattern. .
An energization test was performed on the substrate on which the conductor pattern was formed.
Under a high temperature and high humidity condition of 90 ° C. and a relative humidity of 90%, a conduction test was performed for 1000 hours while applying a DC voltage of 10 V to the conductive wire on the substrate. Table 10 shows the results.
[0150]
[Table 10]

According to Table 10, the specific resistance of the conductor pattern was 2 × 10 ^-5 Ω · cm, and 3 × 10 ^-5 Ω · cm, 3 × 10 after 1000 hours ^-5 Ω · cm, and the change in specific resistance before and after the energization test was slight.
[0151]
[Comparative Example 4]
A conductive adhesive material was prepared in the same manner as in Example 8 except that 0.1 μm Ag particles were used as the conductive particles, and the same evaluation as in Example 8 was performed. Table 11 shows the results.
[0152]
[Table 11]

According to Table 11, the specific resistance of the conductor pattern was 2 × 10 before the test. ^-5 Ω · cm, but 4 × 10 ^-5 Ω · cm, and conduction failure due to short-circuit occurred after 1000 hours of energization.
[0153]
[Example 9]
PbO-ZnO-B was added to 200 g of the conductive particles (alumina-Pt-coated Cu particles) obtained in Example 3. ₂ O ₃ 12 g of glass frit (average particle size: 1.6 μm), 0.5 g of ethyl cellulose, and 18 g of terpineol were added, preliminarily mixed by a planetary mill, and kneaded by a three-roll mill to prepare a conductive adhesive material. Next, using this conductive adhesive material, a 200 μm-wide line and a 40 μm-space test pattern are printed on an alumina substrate with a screen printing machine, and then in air and in a nitrogen atmosphere. The resultant was fired at 850 ° C. to form a conductive wire pattern.
Thereafter, the conductivity of the substrate on which the conductive wire pattern was formed was evaluated.
[0154]
[Table 12]

According to Table 12, the specific resistance of the conductor pattern was 4 × 10 for both firing in air and firing in a nitrogen atmosphere. ^-6 Ω · cm, and when the alumina-Pt-coated Cu particles were used as the conductive particles, it was found that the conductivity was sufficiently secured by any of the firing methods of firing in air and firing in a nitrogen atmosphere. .
[0155]
[Comparative Example 5]
A conductive adhesive material was prepared in the same manner as in Example 9 except that 0.3 μm Cu particles were used as the conductive particles, and the same evaluation as in Example 9 was performed. Table 13 shows the results.
[0156]
[Table 13]

According to Table 13, the specific resistance of the conductive wire pattern was 8 × 10 ^-1 Ω · cm, but 4 × 10 ^-6 As low as Ω · cm, it was found that conductivity was not secured by firing in air.
[0157]
Next, an Ag colloid dispersion and a low refractive index paint used in the following examples were prepared by the following method.
"Preparation of Ag colloid dispersion"
A 0.15 mmol / l aqueous solution of silver nitrate and a 0.024 mmol / l aqueous solution of sodium borohydride are mixed, and the obtained colloidal dispersion is concentrated, and an Ag colloid dispersion containing 0.65 mol / l Ag fine particles is dispersed. Liquid N was obtained. The average primary particle diameter of the silver fine particles in the Ag colloid dispersion liquid N was 10 nm.
0.8 g of tetraethoxysilane, 0.8 g of 0.1N hydrochloric acid, and 98.4 g of ethanol were mixed to form a uniform solution, whereby a low refractive index paint P was obtained.
[0158]
[Example 10]
`` Solution preparation ''
The following two types of solutions were prepared.
(Solution n)
After 93 g of the Ag colloid dispersion N was dispersed in 4 liters of pure water, the pH of the dispersion was adjusted to 10 using a 0.1N NaOH aqueous solution to obtain a solution n.
(Solution p)
Sodium tungstate was weighed so as to be 10 mol% with respect to the Ag solid content of the solution n, and dissolved in 1 liter of pure water to obtain a solution p.
[0159]
Next, the solution p was dropped into the solution n over 5 hours while stirring the solution n. Further, a solution prepared by dissolving sodium borohydride in the same molar amount as that of sodium tungstate in this solution P in 1 liter of pure water was added, and 0.05 N acetic acid was added dropwise to the obtained solution over 1 hour to adjust the pH. It was adjusted to 4.0.
Next, this solution was stirred at room temperature (25 ° C.) for 24 hours, and then filtered and washed to remove extra ions and the like. Thereafter, this concentrated solution was further concentrated to 200 ml, to obtain a tungsten oxide-coated Ag colloidal dispersion R having a solid content of 3% by weight.
[0160]
"Adjustment of paint for forming transparent conductive film"
Ag colloid dispersion R coated with tungsten oxide 2g
43 g of ethanol
3g of pure water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic disperser (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a coating S for forming a transparent conductive film.
[0161]
"Deposition"
The coating material S for forming a transparent conductive film was applied on a glass substrate using a spin coater at 150 rpm for 30 seconds, and then dried to form a transparent conductive layer.
Next, on the transparent conductive layer, the above-mentioned low refractive index paint P is applied by the same method, and then the glass substrate is subjected to a heat treatment at 160 ° C. for 30 minutes. A glass substrate was obtained.
[0162]
[Example 11]
"Solution preparation"
The following solution was prepared.
Pure water was added to the concentrated solution obtained in Example 10 from which excess ions and the like had been removed to make a total volume of 4 liters, and the pH of the solution was adjusted to 10 using a 0.1N aqueous NaOH solution. r.
[0163]
Also, sodium gold sulfite (NaAuSO ₃ ) The solution was weighed so that Au was 3 wt% with respect to the Ag solid content in the above solution r, and pure water was further added to obtain a solution 1 liter in total volume.
This solution s was added dropwise to the above solution r over 3 hours. 0.1N acetic acid was added dropwise to the obtained solution over 1 hour to adjust the pH to 4.0.
Next, this solution was stirred at room temperature (25 ° C.) for 24 hours, and then filtered and washed to remove extra ions and the like. Thereafter, the concentrated solution was further concentrated to 200 ml to obtain a tungsten oxide-Au-coated Ag colloidal dispersion T having a solid content of 5% by weight.
[0164]
"Adjustment of paint for forming transparent conductive film"
Tungsten oxide-Au coated Ag colloid dispersion T 2g
43 g of ethanol
3g of pure water
Ethyl Solosolve 2g
Were mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a coating material U for forming a transparent conductive film.
[0165]
"Deposition"
The coating material U for forming a transparent conductive film was applied on a glass substrate using a spin coater under the conditions of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the above-mentioned low refractive index paint P is applied by the same method, and then the glass substrate is subjected to a heat treatment at 160 ° C. for 30 minutes. A glass substrate was obtained.
[0166]
[Example 12]
"Solution preparation"
After 93 g of the Ag colloid dispersion N was dispersed in 4 liters of pure water, the pH of the dispersion was adjusted to 4.8 with 0.1 N acetic acid to obtain a solution t.
Next, MPS (γ-mercaptotriethoxysilane) was weighed so as to be 4 mol% with respect to the Ag solid content of the solution t, dissolved in 0.5 liter of pure water, and the solution was added to the solution t. The solution was gradually added while maintaining the pH at 4.8, and then stirred for 15 minutes to obtain a solution u.
[0167]
Next, to this solution u, a solution obtained by weighing sodium molybdate so as to be 10 mol% with respect to the Ag solid content of the solution u and dissolving it in 0.5 liter of pure water is added. A solution weighed so as to have the same mole as the sodium molybdate and dissolved in 0.3 liter of pure water was added.
Next, 0.05 N acetic acid was added dropwise to this solution over 1 hour, and the pH was adjusted to 4.0 to obtain a solution v.
[0168]
Next, the solution v was stirred at room temperature (25 ° C.) for 24 hours, and then filtered and washed to remove extra ions and the like. Thereafter, this concentrated liquid was further concentrated to 200 ml to obtain a molybdenum oxide-coated Ag colloid dispersion liquid V having a solid content of 5% by weight.
[0169]
"Adjustment of paint for forming transparent conductive film"
Molybdenum oxide-coated Ag colloid dispersion V 2 g
43 g of ethanol
3g of pure water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a coating W for forming a transparent conductive film.
[0170]
"Deposition"
The coating material W for forming a transparent conductive film was applied on a glass substrate using a spin coater under the conditions of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the above-mentioned low refractive index paint P is applied by the same method, and then the glass substrate is subjected to a heat treatment at 160 ° C. for 30 minutes. A glass substrate was obtained.
[0171]
Example 13
"Solution preparation"
Pure water was added to the concentrated solution obtained in Example 12 from which excess ions and the like had been removed to make the total volume 4 liters, and then the pH of this solution was adjusted to 10 using a 0.1N NaOH aqueous solution, Solution w was used.
[0172]
Next, the solution s of Example 11 was added dropwise to the solution w over 3 hours. 0.1N acetic acid was added dropwise to the obtained solution over 1 hour to adjust the pH to 4.0.
Next, this solution was stirred at room temperature (25 ° C.) for 24 hours, and then filtered and washed to remove extra ions and the like. Thereafter, the concentrated solution was further concentrated to 200 ml to obtain a molybdenum oxide-Au coated Ag colloidal dispersion X having a solid content of 5% by weight.
[0173]
"Adjustment of paint for forming transparent conductive film"
Molybdenum oxide-Au coated Ag colloid dispersion X 2 g
43 g of ethanol
3g of pure water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint Y for forming a transparent conductive film.
[0174]
"Deposition"
This transparent conductive film forming paint Y was applied on a glass substrate using a spin coater under the conditions of 150 rpm for 30 seconds, and then dried to obtain a transparent conductive layer.
Next, on the transparent conductive layer, the above-mentioned low refractive index paint P is applied by the same method, and then the glass substrate is subjected to a heat treatment at 160 ° C. for 30 minutes. A glass substrate was obtained.
[0175]
"Evaluation"
Surface resistance, reflectance, transmittance, scratch resistance, HCl (hydrochloric acid) resistance, NaCl (brine) resistance, H resistance of the glass substrates with transparent conductive films of Examples 10 to 13 obtained as described above. ₂ O ₂ (Hydrogen peroxide) properties and paint stability were evaluated.
The evaluation method was exactly the same as the evaluation method of the transparent conductive film with antireflection function (low-reflection transparent conductive film) in Examples 4 to 7 and Comparative Example 3 described above.
Tables 14 to 17 show the evaluation results of Examples 10 to 13.
[0176]
[Table 14]

[0177]
[Table 15]

[0178]
[Table 16]

[0179]
[Table 17]

[0180]
According to the results of Tables 14 to 17, in Examples 10 to 13, good results were obtained in all the evaluation items, and not only excellent in transparency, conductivity, antistatic property, etc., but also in resistance. HCl resistance, NaCl resistance, H resistance ₂ O ₂ It was confirmed that environmental resistance such as resistance and scratch resistance were good. It was also confirmed that the coating stability was good.
[0181]
【The invention's effect】
As described above, according to the conductive particles of the present invention, since the coating layer made of oxide is formed on the surface of the metal particles, the conductive particles have excellent transparency, conductivity, antistatic properties, and electromagnetic wave shielding properties. In addition, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be remarkably improved.
[0182]
According to the conductive adhesive material of the present invention, since it contains the conductive particles of the present invention, in addition to being excellent in conductivity, it has environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. It can be significantly improved.
[0183]
According to the paint for forming a transparent conductive film of the present invention, since it contains the conductive particles of the present invention, it has excellent transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance, acid resistance, Environmental resistance such as oxidation resistance and ultraviolet resistance can be significantly improved.
Further, since a coating layer made of an oxide is formed on the surface of the metal particles, the adhesion between the transparent conductive film formed using the transparent conductive film forming paint and a substrate such as glass is improved. Can be. Therefore, even during use, there is no possibility that defects such as peeling and scratches may occur.
[0184]
According to the transparent conductive film of the present invention, since the transparent conductive layer formed by applying the transparent conductive film forming paint of the present invention is provided, it has excellent transparency, conductivity, antistatic property, and electromagnetic wave shielding property. In addition, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be remarkably improved.
In addition, since the adhesion between the transparent conductive film and a substrate such as glass is improved, there is no possibility that defects such as peeling and scratching may occur even during use.
[0185]
According to the display device of the present invention, since the transparent conductive film of the present invention is formed on the display surface, the display surface is excellent in transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance, and acid resistance. Environmental resistance such as resistance, oxidation resistance, and ultraviolet resistance can be significantly improved.
Further, since the adhesion between the display surface and the transparent conductive film is improved, there is no possibility that problems such as peeling and scratches may occur during use, and visibility and reliability on the display surface can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a conductive particle according to one embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating an example of a cross-sectional structure of a coating layer of a conductive particle according to an embodiment of the present invention.
FIG. 3 is a schematic view showing another example of a cross-sectional structure of a coating layer of a conductive particle according to one embodiment of the present invention.
FIG. 4 is a sectional view showing a transparent conductive film according to one embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a low-reflection transparent conductive film according to one embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a modified example of the low-reflection transparent conductive film according to one embodiment of the present invention.
FIG. 7 is a cross-sectional view showing another modification of the low-reflection transparent conductive film according to one embodiment of the present invention.
FIG. 8 is a cross-sectional view illustrating a display surface of the display device according to the embodiment of the present invention.
[Explanation of symbols]
1 metal particles
2 Coating layer
3 oxide layer
4 Second metal particles
5 Coating layer
11 Glass substrate
12 Transparent conductive layer
21 Anti-reflection layer
22, 31, 41 Low reflection transparent conductive film
51 Display panel

Claims (12)

Conductive particles characterized in that a coating layer made of an oxide is formed on the surface of metal particles. The oxide according to claim 1, wherein the oxide contains one or more selected from silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, molybdenum oxide, tungsten oxide, and chromium oxide. 2. The conductive particles according to 1. The conductive particles according to claim 1, wherein the coating layer contains a second metal. The conductive particles according to claim 3, wherein the second metal is a metal different from the metal particles. The method according to claim 3, wherein the second metal is one or more selected from gold, platinum, palladium, osmium, iridium, ruthenium, rhenium, rhodium, silver, and copper. Conductive particles. The conductive particles according to claim 3, 4 or 5, wherein the second metal is deposited in voids of the coating layer. The conductive particle according to any one of claims 1 to 6, wherein the metal particle includes one or more selected from silver, copper, and nickel. A conductive adhesive material comprising the conductive particles according to claim 1. A paint for forming a transparent conductive film, comprising the conductive particles according to claim 1. A transparent conductive film comprising a transparent conductive layer formed by applying the transparent conductive film forming paint according to claim 9. The transparent conductive film according to claim 10, wherein an anti-reflection layer is formed on one main surface or both main surfaces of the transparent conductive layer. A display device, wherein the transparent conductive film according to claim 10 is formed on a display surface.

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