JP4187487B2 - Coating composition, coating film thereof, antireflection film, antireflection film, and image display device - Google Patents

Description

【００８６】
（式中、−Ａは、−ＣＨ₂ＯＨ、−ＣＯＯＣＨ₃、−ＣＮ、又は−ＣＯＯＨであり、特に−Ａが−ＣＨ₂ＯＨである場合には溶解性に優れ、アセトン、酢酸、テトラヒドロフラン（ＴＨＦ）等の溶剤に可溶なので好ましい。ｎは整数であり、特に１〜３の範囲の整数が好ましい。）
が、電離放射線硬化性基と熱硬化性極性基とを併せ持つフッ素含有モノマーとして好適に用いられる。
【００８７】
その他にも、電離放射線硬化性基と熱硬化性極性基とを併せ持つフッ素含有成分（ａ’）としては、アクリル又はメタクリル酸の部分及び完全フッ素化アルキル、アルケニル、アリールエステル類（例えば下記式２又は下記式３で表される化合物）
【００８８】
【化２】

【００８９】
（式中、Ｒ¹は水素原子、炭素数１〜３のアルキル基又はハロゲン原子を表す。Ｒｆは完全又は部分フッ素化されたアルキル基、アルケニル基、ヘテロ環またはアリール基を表す。Ｒ²及びＲ³はそれぞれ独立に水素原子、アルキル基、アルケニル基、ヘテロ環、アリール基又は上記Ｒｆで定義される基を表す。Ｒ¹、Ｒ²、Ｒ³及びＲｆはそれぞれフッ素原子以外の置換基を有していても良い。また、Ｒ²、Ｒ³及びＲｆの任意の２つ以上の基が互いに結合して環構造を形成しても良い。）
【００９０】
【化３】

【００９１】
（式中、Ｂは完全または部分フッ素化されたｎ価の有機基を表す。Ｒ⁴は水素原子、炭素数１〜３のアルキル基又はハロゲン原子を表す。Ｒ⁴はフッ素原子以外の置換基を有していても良い。ｎは２乃至８の整数を表す。）、
完全または部分フッ素化ビニルエーテル類、完全または部分フッ素化ビニルエステル類、完全または部分フッ素化ビニルケトン類等を例示することができる。
【００９２】
フッ素含有成分（ａ）として用いられるオリゴマー、ポリマーは、先ず、電離放射線硬化性基と熱硬化性極性基とを併せ持つフッ素含有成分（ａ’）に属するモノマー又はオリゴマー、特に好ましくは、上記１，１，２−トリフルオロアリルオキシモノマーのようにエチレン性不飽和結合等の電離放射線硬化性基を一つだけ有するモノマー又はオリゴマーを重合させることによって、フッ素原子を含有し、且つ、極性基を有するペンダント構造を有する中間体ポリマーを合成する。中間体ポリマーは、フッ素含有成分（ａ）に属するモノマー又はオリゴマーと、フッ素含有成分（ａ）に属さないモノマー又はオリゴマーとの共重合体であってもよい。同様の中間体ポリマーは、電離放射線硬化性基だけ有するフッ素含有モノマーと、電離放射線硬化性基と極性基を併せ持つフッ素非含有モノマーとを共重合させることでも得られる。
【００９３】
ここで、電離放射線硬化性基と極性基を併せ持つフッ素非含有モノマーとしては、エポキシ（メタ）アクリレート類、グリシジル（メタ）アクリレート類、グリセロールモノ（メタ）アクリレート類、グリセロールジ（メタ）アクリレート類、２−ヒドロキシエチル（メタ）アクリレート及びそのカプロラクトン変性品、２−ヒドロキシプロピル（メタ）アクリレート及びそのカプロラクトン変性品、リン酸（メタ）アクリレート類、ポリエチレングリコール（メタ）アクリレート類、ポリプロピレングリコール（メタ）アクリレート類、ポリエチレングリコール−ポリプロピレングリコール共重合体の（メタ）アクリレート類、コハク酸アクリレート類、アクリルアミド等を例示することができる。
【００９４】
そして、上記中間体ポリマーの極性基に対して重縮合や重付加可能な官能基とエチレン性不飽和結合等の電離放射線硬化性基とを併せ持つ化合物を反応させると、中間体ポリマーの極性基の一部を介して電離放射線硬化性基が導入され、電離放射線硬化性基と極性基を併せ持つフッ素含有成分（ａ’）に属するオリゴマー、ポリマーが合成される。中間体ポリマーの極性基に対して重縮合や重付加可能な官能基は、中間体ポリマーの極性基として例示されたものの中から適宜選択することができる。なお、中間体ポリマーに電離放射線硬化性基と共に導入される残基部分にフッ素原子が置換している場合には、得られるオリゴマー又はポリマーの屈折率がさらに低くなるので好ましい。
【００９５】
フッ素含有成分（ａ’）であるオリゴマー、ポリマー中に含まれる電離放射線硬化性基の量と極性基の量の比（電離放射線硬化性基：極性基）が、２０モル％：８０モル％〜９０モル％：１０モル％の範囲にあると電離放射線硬化性と支持体に対する密着性のバランスがとれているので好ましい。
【００９６】
本発明においては必須のバインダー成分としてフッ素含有成分（ａ）を用いるが、必要に応じて他のバインダー成分をフッ素含有成分（ａ）と共に用いることができる。塗膜の硬度、強度、密着性などを向上させたり或いは屈折率を所定の値に調整するなどのように諸性質を制御するために、本発明の目的を逸脱しない範囲で、フッ素を含有しないバインダー成分を用いても良い。他のバインダー成分としては、非反応性のフッ素非含有オリゴマー及びポリマー、非反応性のフッ素含有オリゴマー及びポリマー、硬化反応性のフッ素非含有モノマー、オリゴマー及びポリマーを適宜使用できる。
【００９７】
例えば、非反応性のフッ素非含有オリゴマー及びポリマーとしては、光学薄膜を形成するために従来から用いられている透明樹脂、例えば、ポリアクリル酸、ポリメタクリル酸、ポリアクリレート、ポリメタクリレート、ポリオレフィン、ポリスチロール、ポリアミド、ポリイミド、ポリビニルクロライド、ポリビニルアルコール、ポリビニルブチラール、ポリカーボネートのような重合性官能基を有さない非硬化反応性ポリマーを挙げることができる。
【００９８】
非反応性のフッ素含有オリゴマー又はポリマーとしては、例えば、ポリテトラフルオロエチレン；４−フルオロエチレン−６−フルオロプロピレン共重合体；４−フルオロエチレン−エチレン共重合体；ポリビニルフルオライド；ポリビニリデンフルオライド；フッ素変性シリコーン樹脂等を例示することができる。
【００９９】
また、硬化反応性のフッ素非含有モノマー、オリゴマー及びポリマーとしては、エチレン性不飽和結合のような重合性官能基を有するモノマーやオリゴマー、例えば、２−ヒドロキシエチル（メタ）アクリレート、２−ヒドロキシプロピル（メタ）アクリレート、ヒドロキシブチルアクリレート、２−ヒドロキシ３−フェノキシプロピルアクリレート、カルボキシポリカプロラクトンアクリレート、アクリル酸、メタクリル酸、アクリルアミド等の単官能（メタ）アクリレート；エチレングリコールジアクリレート、ペンタエリスリトールジアクリレートモノステアレート等のジアクリレート；トリメチロールプロパントリアクリレート、ペンタエリスリトールトリアクリレート等のトリ（メタ）アクリレート、ペンタエリスリトールテトラアクリレート誘導体やジペンタエリスリトールペンタアクリレート等の多官能（メタ）アクリレート、或いは、これらのラジカル重合性モノマーが重合したオリゴマーを例示することができる。また、上記非硬化反応性ポリマーにエチレン性不飽和結合のような重合性官能基を導入した硬化反応性ポリマーを例示することができる。さらに上記フッ素含有成分（ａ’）の中間体ポリマーを製造する原料として例示したような電離放射線硬化性基と極性基を併せ持つフッ素非含有モノマーも用いることができる。
【０１００】
他のバインダー成分は、フッ素含有成分（ａ）との間で架橋結合を形成できる電離放射線硬化性基、特にエチレン性不飽和結合を有することが好ましい。また、他のバインダー成分であるモノマーは、エチレン性不飽和結合等の電離放射線硬化性基を一分子内に２つ以上持つものが好ましく、その中でも多官能（メタ）アクリレートが好ましい。さらに、塗膜の屈折率を低くするためには、他のバインダー成分もフッ素原子を有していることが好ましい。
【０１０１】
また、本発明のコーティング組成物には、フッ素含有成分と無機超微粒子の相溶性を向上させるために、フェドルフ（Fedros）が提案したＳＰ値の算定式に基づくＳＰ値が８．５〜１２のフッ素非含有モノマー及び／又はオリゴマーを配合してもよい。コーティング液の状態では無機超微粒子が充分に分散し透明状態であっても、塗膜が乾燥する途中で無機超微粒子が凝集して白化する場合がある。これに対して本発明のコーティング組成物に、フッ素含有成分と無機超微粒子の両方に親和性の大きいフッ素非含有モノマー及び／又はオリゴマーを配合することによって、このような塗膜の白化を防止することができる。
【０１０２】
ここで、２官能以上のエチレン性不飽和結合を有し、且つ、ＳＰ値が８．５〜１２のフッ素非含有モノマー及び／又はオリゴマーとして、具体的には、アクリル酸、メタクリル酸、アクリルアミド等の単官能（メタ）アクリレート；ペンタエリスリトールトリアクリレート、エチレングリコールジアクリレート、ペンタエリスリトールジアクリレートモノステアレート等のジアクリレート；トリメチロールプロパントリアクリレート、ペンタエリスリトールトリアクリレート等のトリ（メタ）アクリレート、ペンタエリスリトールテトラアクリレート誘導体やジペンタエリスリトールペンタアクリレート等の多官能（メタ）アクリレート、或いは、これらのラジカル重合性モノマーが重合したオリゴマーを例示することができる。これらのフッ素非含有モノマー及び／又はオリゴマーは、２種以上を組み合わせて用いても良い。
【０１０３】
本発明に係るコーティング組成物を大面積へ均一に塗工するためには、後述するようにケトン系溶剤又はその混合物を用いるのが好ましいが、ケトン系溶剤又はその混合物のＳＰ値も上記８．５〜１２の範囲に収まるので、この範囲のＳＰ値を持つフッ素非含有モノマー又はオリゴマーを用いる場合には、フッ素含有成分と無機超微粒子の相溶性が向上するのと同時に、コーティング組成物の溶剤への溶解性や塗工適性が向上するという効果もある。
【０１０４】
フッ素含有成分と無機超微粒子の相溶性を向上させるためのフッ素非含有モノマー及び／又はオリゴマーは、本発明のコーティング組成物中の固形分全量に対して、通常０．１〜７０重量％程度の割合で含有させる。
【０１０５】
上記したフッ素含有成分（ａ）に属するモノマー、オリゴマー、ポリマー、及び、フッ素含有成分（ａ）に属しないモノマー、オリゴマー、ポリマーを適宜組み合わせて、成膜性、塗工適性、電離放射線硬化の架橋密度、フッ素含有量、熱硬化性を有する極性基の含有量等の諸性質を調節することができる。例えば、モノマー、オリゴマーにより架橋密度と加工適性が向上し、ポリマーによりコーティング組成物の成膜性が向上する。
【０１０６】
本発明においては、フッ素含有成分（ａ）の中から数平均分子量（ゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定したポリスチレン換算数平均分子量）が２，０００以下のモノマー、数平均分子量が２，０００〜１０，０００のオリゴマー、及び、数平均分子量が１０，０００〜２００，０００のポリマーを適宜組み合わせ、さらに必要に応じてフッ素含有成分（ａ）以外のバインダー成分を組み合わせて、塗膜の諸性質を容易に調節することが可能である。
【０１０７】
特に、フッ素含有成分（ａ）に属する数平均分子量が１０，０００〜２００，０００であるポリマーと、エチレン性不飽和結合を２つ以上有する多官能（メタ）アクリレートを組み合わせることにより、塗工適性、成膜性、膜硬度、膜強度などを含めた諸物性のバランスがとり易いので好ましい。
【０１０８】
本発明においては、コーティング組成物に配合するフッ素含有成分（ａ）及び当該フッ素含有成分（ａ）以外のフッ素含有成分に含まれるフッ素の量によって、バインダー成分全体に含まれるフッ素の量が決まる。そして、フッ素含有成分（Ａ）を主体とするバインダー成分のフッ素含有量を制御することによって、得られる塗膜の屈折率を調節することができる。すなわち、コーティング組成物に配合するフッ素含有成分（ａ）又はそれ以外のフッ素含有成分のフッ素含有率が高いほど又は配合量が多いほど、コーティング組成物及び当該コーティング組成物を用いて形成した塗膜のフッ素含有量が多くなり、屈折率が低くなる。一方、コーティング組成物に配合するフッ素含有成分（ａ）又はそれ以外のフッ素含有成分のフッ素含有率が低いほど又は配合量が少ないほど、コーティング組成物及び当該コーティング組成物を用いて形成した塗膜のフッ素含有量が少なくなり、屈折率が高くなる。
【０１０９】
塗膜の屈折率を充分に低くするためには、フッ素含有成分（ａ）の屈折率が１．４５以下、特に１．４２以下であることが好ましく、フッ素含有成分（Ａ）以外のフッ素含有成分の屈折率も１．４５以下、特に１．４２以下であることが好ましい。また、フッ素含有率の点では、フッ素含有成分（ａ）を主体とする全バインダー成分の炭素に結合している水素の５モル％以上、特に２０モル％以上がフッ素原子で置換されていることが好ましい。
【０１１０】
しかし、バインダー成分のフッ素含有量が大きくなり過ぎると、当該バインダー成分を含有するコーティング組成物から形成される塗膜の硬度や強度が低下し、低屈折率層等の光学薄膜としての実用に耐えられなくなってしまうという問題がある。従来は、フッ素含有成分の屈折率が約１．４２以下となると、フッ素含有量が大きくなり過ぎてしまい、充分な硬度や強度を有する塗膜を得ることが困難であった。
【０１１１】
これに対して、本発明においては後述するように、フッ素含有成分（ａ）を主体とするバインダー成分に無機超微粒子を配合することにより、コーティング組成物中の全バインダー成分の分子を構成する炭素に結合している水素原子の２０モル％以上がフッ素原子で置換されているものを用いる場合でも、或いは、屈折率が１．４２以下のフッ素含有成分を用いる場合でも、実用に耐え得る硬度や強度を有する塗膜を形成することが可能である。なお、フッ素含有成分のフッ素置換率は、ＮＭＲ法や元素分析法により測定することができる。
【０１１２】
本発明のコーティング組成物に配合される無機超微粒子（Ｂ）は、フッ素含有量の高いバインダー系（Ａ）を硬化させてなるバインダーにより形成された塗膜に対して、実用上耐え得る硬度及び強度を付与するための成分である。
【０１１３】
すなわち、フッ素含有成分（ａ）を主体とするバインダー系（Ａ）に無機超微粒子をコロイド状に分散させた塗工液を被塗工体の表面に塗布し、乾燥などの方法で固化させた後、さらに電離放射線硬化させることによって、上記バインダー系（Ａ）の硬化物からなるバインダー中に無機超微粒子が均一に分散した塗膜が得られる。この塗膜は、均一に分散した無機超微粒子の凝集力及び粒子自体の硬さによって引き締められるので、屈折率を下げるためにバインダー成分のフッ素含有量を高めた場合でも当該塗膜の硬度及び強度の著しい低下を避けることができ、実用上耐え得る硬度及び強度を有している。
【０１１４】
また、本発明のコーティング組成物中にコロイド状態で分散し得る無機超微粒子（Ｂ）は、フッ素含有成分（ａ）及び／又はそれ以外のフッ素含有成分の屈折率低下作用及び成膜性に全く又は僅かしか影響しない少量で、塗膜を引き締める効果が充分に得られ、屈折率を上げたり膜を脆くするような量を配合する必要はない。
【０１１５】
本発明のコーティング組成物は、溶剤を用いて塗工作業に用いられる濃度に最初から調製する場合のほか、溶剤を全く或いは少量しか含有しない高濃度の状態で保存し、使用直前に溶剤を加えて塗工作業に用いられる濃度に調節する場合がある。また、フッ素含有成分として、液状のフッ素含有モノマー及び／又はオリゴマーを比較的多量に用いることによって、溶剤を用いずにコーティング組成物を塗工液の状態に調製できる場合もある。いずれの場合であっても本発明においては、無機超微粒子（Ｂ）は、最終的に塗工液中でコロイド状の形態となって均一に分散可能なものであることが必要である。
【０１１６】
従って、無機超微粒子（Ｂ）としては、本発明のコーティング組成物を塗工液に調製するための溶剤中に、又は、本発明のコーティング組成物を溶剤を用いずに塗工液に調製するための液状のフッ素含有モノマー及び／又はオリゴマー中に、コロイド状の形態となって均一に分散させることが可能なものであることが必要である。
【０１１７】
本発明に係るコーティング組成物には、比較的少量の無機超微粒子を配合するだけでも充分に塗膜の硬度及び強度を向上させることが可能であり、無機超微粒子の配合によりフッ素含有成分の濃度が希釈されて屈折率低下作用に悪影響を及ぼす弊害を完全に排除し或いは僅かな程度に止めることが可能である。しかしながら、無機超微粒子を比較的多めに用いる場合には、フッ素含有成分による屈折率低下作用に悪影響を及ぼす可能性が全くない訳ではないので、無機超微粒子としては屈折率が１．６０以下、特に１．５５以下のものが好ましく用いられる。例えば、アルミナＡｌ₂Ｏ₃（屈折率：１．５３）、シリカＳｉＯ₂（屈折率１．４６）、フッ化マグネシウムＭｇＦ₂（屈折率１．３８）、フッ化カルシウムＣａＦ₂（屈折率１．３６）等を例示することができ、これらの中から上記したように、溶剤又はモノマー及び／又はオリゴマー中にコロイド状分散可能なものを選択して用いるのが好ましい。特に低い屈折率が要求される場合には、上記例示の無機超微粒子のなかでもコロイダルシリカ（ＳｉＯ₂）微粒子を用いるのが好ましい。また、塗膜に充分な硬度を付与することが優先される場合には、アルミナ（Ａｌ₂Ｏ₃）微粒子を用いるのが好ましい。
【０１１８】
また、無機超微粒子（Ｂ）は、塗膜に充分な透明性を確保するために、いわゆる超微粒子サイズのものを用いる。ここで「超微粒子」とはサブミクロンオーダーの粒子のことであり、一般的に「微粒子」と呼ばれている数μｍから数１００μｍの粒子径を有する粒子よりも粒子径の小さいものを意味している。本発明において用いられる無機超微粒子（Ｂ）の具体的なサイズは、本発明のコーティング組成物が適用される光学用薄膜の用途及びグレードによっても相違するが、一般的には一次粒子径が１ｎｍ〜５００ｎｍの範囲のものを用いるのが好ましい。一次粒子径が１ｎｍ未満では、塗膜に充分な硬度及び強度を付与することが困難になり、一方、一次粒子径が５００ｎｍを超えると、塗膜の透明性が損なわれ用途によっては適用不可能となる場合がある。無機超微粒子の一次粒子径は、走査型電子顕微鏡（ＳＥＭ）等により得られる二次電子放出のイメージ写真から目視計測してもよいし、動的光散乱法や静的光散乱法等を利用する粒度分布計等により機械計測してもよい。
【０１１９】
上記した一次粒子径の範囲のうち、一次粒子径が１〜１００ｎｍの無機超微粒子（Ｂ）は、反射防止膜の低屈折率層のような極薄の光学薄膜を形成するのに好適であり、一次粒子径が１００〜５００ｎｍの無機超微粒子（Ｂ）は、光学薄膜のうちでも比較的厚めのモスアイ（Mos-eye）構造膜を形成するのに好適である。
【０１２０】
なお、無機超微粒子は、コロイド状に分散可能で塗膜の硬度及び強度を確保することができ、且つ、サブミクロンオーダーのサイズで透明性を確保できるものである限り、その粒子形状が球状であっても針状であっても、その他どのような形状であっても本発明に用いることができる。
【０１２１】
無機超微粒子の一部が金属水酸化物になっており、水が吸着して水和した構造をとっていると、溶剤又は液状のモノマー及び／又はオリゴマー中でコロイド状の形態に分散させやすいので好ましい。
【０１２２】
また、無機超微粒子の表面を疎水化処理することにより、溶剤又は液状のモノマー及び／又はオリゴマー中での分散性を向上させることができ、コロイド状の形態に分散させやすくなる。無機超微粒子の表面には水酸基が多く存在し、フッ素含有成分と無機超微粒子の親和性がそれほど良くないので、本発明のコーティング組成物中に多量の無機超微粒子を配合する場合には、無機超微粒子が充分に分散したコーティング液が得られるとしても、当該コーティング液を塗工後に乾燥させる過程において塗膜内で無機超微粒子の凝集が起こり、塗膜が白化する場合がある。これに対して、無機超微粒子を疎水化処理することにより撥水性の強いフッ素含有成分に対する無機超微粒子の相溶性が向上するので、このような白化を防止できるという効果も得られる。
【０１２３】
無機超微粒子は、低分子有機化合物で被覆することにより疎水性を付与することができる。具体的には、低分子有機化合物を有機溶剤中に溶解させておき、この溶液中に、無機超微粒子を分散させた後に有機溶剤を完全に蒸発除去することにより、被覆できる。低分子有機化合物としては、例えば、ステアリン酸、ラウリン酸、オレイン酸、リノール酸、リノレイン酸のような低分子有機カルボン酸、及び、低分子有機アミン等を例示することができる。
【０１２４】
また、無機超微粒子をシランカップリング剤やチタネートカップリング剤等のカップリング剤で表面処理することによっても疎水化することができる。カップリング剤の中でも、フッ素原子を含有するシランカップリング剤（フッ素系シランカップリング剤）により無機超微粒子の表面を疎水化処理すると、特にフッ素含有成分に対して優れた相溶性が得られ、塗膜の白化を有効に防止できる。
【０１２５】
ここで、シランカップリング剤としては具体的に、３−グリシドキシプロピルトリメトキシシラン、３−グリシドキシプロピルメチルジメトキシシラン、２−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、３−アミノプロピルトリエトキシシラン、３−アミノプロピルトリメトキシシラン、Ｎ−（２−アミノエチル）３−アミノプロピルメチルジエトキシシラン、３−メルカプトプロピルトリメトキシシラン、ビニルトリメトキシシラン、ビニルトリエトキシシラン、ビニルトリス（２−メトキシエトキシ）シラン、３−メタクリロキシプロピルトリメトキシシラン等を例示することができる。
【０１２６】
これらのうち、反応性基を持つシランカップリング剤で処理した場合は、バインダー成分の熱硬化性極性基とシランカップリング剤のアルコキシ基及び熱硬化が可能な官能基が容易に強固な結合を形成し、塗膜の強度を向上させることができる。
【０１２７】
チタネートカップリング剤としては、具体的には、味の素（株）より市販されている、製品名プレンアクトＫＲ−ＴＴＳ、ＫＲ−４６Ｂ、ＫＲ−５５、ＫＲ−４１Ｂ、ＫＲ−３８Ｓ、ＫＲ−１３８Ｓ、ＫＲ−２３８Ｓ、３３８Ｘ、ＫＲ−４４、ＫＲ−９ＳＡ、ＫＲ−ＥＴ等が例示でき、更に、テトラメトキシチタン、テトラエトキシチタン、テトライソプロポキシチタン、テトラｎ−プロポキシチタン、テトラｎ−ブトキシチタン、テトラｓｅｃ−ブトキシチタン、テトラｔｅｒｔ−ブトキシチタン等の金属アルコキシドも使用することができる。
【０１２８】
フッ素系シランカップリング剤としては、例えば、ＧＥ東芝シリコーン（株）製のフルオロアルキルシランカップリング剤である商品名ＴＳＬ８２６２、ＴＳＬ８２５７、ＴＳＬ８２３３、ＴＳＬ８２３１等を例示することができる。
【０１２９】
疎水化処理された無機超微粒子は市販品として入手することも可能である。そのような市販品としては、例えば、ＳｉＯ₂微粒子の表面に有機低分子化合物を吸着させることにより表面を疎水性にした製品があり、日産化学（株）が商品名オルガノシリカゾルとして供給している。
【０１３０】
本発明のコーティング組成物には、フッ素含有成分（ａ）を含むバインダー成分、無機超微粒子及びその他の成分を含む固形分全量に対して、無機超微粒子を０．１〜７０重量％の割合で含有させるのが好ましく、下限を０．３重量％以上とし、且つ／又は、上限を５０重量％以下、特に３０重量％以下とすることが、さらに好ましい。ここで、コーティング組成物の固形分とは溶剤以外の全ての成分であり、液状のモノマー及びオリゴマーも固形分に含まれる。コーティング組成物中の無機超微粒子の配合割合が少なすぎると、塗膜の硬度及び強度が充分に向上せず、一方、無機超微粒子の配合割合が多すぎると、フッ素含有成分が希釈されて屈折率を充分に下げることができなくなると共に、コーティング組成物中のバインダー成分が相対的に少なくなって塗膜が脆くなり、膜強度が低下する。本発明に係るコーティング組成物に、無機超微粒子を固形分基準で０．１〜７０重量％の割合で含有させることにより、フッ素含有成分の屈折率低下作用に全く或いはほとんど悪影響を及ぼすことなく、塗膜の硬度及び強度を向上させることが可能であり、非常に低い屈折率を有し、且つ、硬度及び強度にも優れた塗膜が得られる。
【０１３１】
バインダー系（Ａ）中の熱硬化性極性基が水酸基であり、且つ、無機超微粒子（Ｂ）の表面が部分的に金属水酸化物となって水酸基を生じている場合には、バインダー成分と無機超微粒子（Ｂ）の水酸基同士が加熱により脱水重縮合を起こして共有結合を形成できるので、塗膜の硬度、強度が向上する。バインダー成分の熱硬化性極性基が水酸基でない場合でも、無機超微粒子（Ｂ）の表面の水酸基と共有結合を形成できる場合がある。
【０１３２】
また、無機超微粒子（Ｂ）の表面に、重合性官能基を付与することによって、バインダー成分と無機超微粒子（Ｂ）の間の共有結合を増やし、塗膜の硬度、強度を意図的に向上させることができる。
【０１３３】
無機超微粒子（Ｂ）の表面の重合性官能基は、バインダー成分の電離放射線硬化性基及び／又は熱硬化性極性基と重合して共有結合を形成できるものであれば特に限定されず、無機超微粒子（Ｂ）と組み合わされるバインダー成分が有する電離放射線硬化性基及び／又は熱硬化性極性基に合わせて適切な反応形式のものを用いることができる。一般的には、組み合わされるバインダー成分が有するものと同様の電離放射線硬化性基及び／又は熱硬化性極性基であればよい。
【０１３４】
例えば、エチレン性不飽和結合を有するフッ素含有成分（ａ）と、同じくエチレン性不飽和結合を有する無機超微粒子（Ｂ）を組み合わせ、必要に応じて光ラジカル重合開始剤を添加することができ、或いは、エポキシ基を有するフッ素含有成分（ａ）と、アミノ基や水酸基を有する無機超微粒子（Ｂ）を組み合わせ、必要に応じてエポキシ反応の硬化剤を添加することができる。無機超微粒子（Ｂ）への官能基の導入方法、及び、硬化反応の取り扱いの簡便性を考慮すると、無機超微粒子（Ｂ）表面の重合性官能基としては、エチレン性不飽和結合等の電離放射線硬化性基を用いるのが好ましい。
【０１３５】
無機超微粒子の表面に、重合性官能基、好ましくはエチレン性不飽和結合等の電離放射線硬化性基を付与する方法は、以下の３つに大別される。
【０１３６】
（１）重合性官能基を含むモノマー、オリゴマー、ポリマーを無機超微粒子の表面に吸着させる方法。
【０１３７】
（２）重合性官能基を有するカップリング剤で無機超微粒子の疎水化を行なうと同時に、表面に反応性の官能基を導入する方法。
【０１３８】
（３）反応性の官能基を持つポリマーを無機超微粒子の表面にグラフトさせる方法。
【０１３９】
上記（１）の手法では、無機超微粒子の分散溶液に重合性官能基を含む成分を添加する際に、例えば、無機超微粒子の表面が親水性であれば極性基をもつものを（水素結合、静電気の利用、親水性相互作用の利用）、疎水性であれば親水性の環境で疎水性のものを（疎水性の相互作用の利用）、また、無機超微粒子が酸性のものであれば塩基性（酸−塩基相互作用の利用）のものを選定すると、無機超微粒子表面へ吸着する量を増加させることができる。
【０１４０】
上記（２）の手法では、先に例示したカップリング剤を必要であれば酸又は塩基触媒の存在下で無機超微粒子の表面の極性基と重縮合反応させることで容易に導入することができる。この際、使用可能なカップリング剤としては、先に疎水化処理の際に列挙したものに加え、末端や側鎖にアルコキシ基を導入したモノマー、オリゴマー、ポリマーも使用することができる。
【０１４１】
上記（３）の無機超微粒子表面へのポリマーのグラフト化反応は、以下の３つに大別される。
【０１４２】
（３ａ）ポリマー成長末端を無機超微粒子で補足させる方法
無機超微粒子の表面に存在する水酸基（−ＯＨ）はラジカルなどの活性種を補足する作用があるため、例えば、無機超微粒子の存在下で多官能モノマー又はオリゴマーの重合反応を行うか、或いは、多官能モノマー又はオリゴマーの重合系に無機超微粒子を添加することにより微粒子表面に重合性官能基を有するモノマー、オリゴマー又はポリマーを結合させることができる。塊状重合など、モノマー中に微粒子を練りこんで重合反応を行うときには有効であるが、結合の効率は悪い。
【０１４３】
（３ｂ）無機超微粒子の表面から重合反応を開始させる方法
ラジカル重合開始剤などの重合開始活性種を予め無機超微粒子の表面に形成しておき、多官能モノマー又はオリゴマーを用いて微粒子表面からポリマーを成長させる方法である。高分子量の重合反応性ポリマー鎖が得られやすいが、連鎖移動等の制御が困難である。
【０１４４】
（３ｃ）反応性基を持つポリマーと無機超微粒子表面の水酸基を結合させる方法
２官能以上の反応性基を有するポリマーを用い、当該ポリマー末端の反応性基と無機超微粒子表面の水酸基とを直接結合させるか、或いは、ポリマー末端の反応性基又は無機超微粒子表面の水酸基のいずれか又は両方に他の反応性基を結合させた後に結合させる方法である。ポリマーとして多くの種類を用いることができ、比較的簡便な操作で結合効率も良好である。
【０１４５】
無機超微粒子表面へポリマーを結合させる方法は、粒子表面の水酸基と反応性基を持つポリマー間の脱水重縮合反応を利用するため、ポリマー及びその溶液中に無機超微粒子を分散させて８０℃以上で３時間以上加熱する。
【０１４６】
重合性官能基を有する無機超微粒子（Ｂ）は市販品として入手することも可能である。そのような市販品としては、例えば、フランスのクラリアント社（Clariant Corp.）が商品名ハイリンクＯＧ（Highlink OG）シリーズとして供給する表面処理ＳｉＯ₂微粒子のうち、エチレン性不飽和結合や水酸基やアミノ基などの反応性基を含有する反応性有機基を結合させた製品を例示することができる。より具体的に、エチレン性不飽和結合を有する製品としては、ＳｉＯ₂微粒子表面のシラノール基に、２−ヒドロキシエチル（メタ）アクリレートや２−ヒドロキシプロピル（メタ）アクリレートのような水酸基含有（メタ）アクリレートをエーテル結合させたものがある。水酸基を有する製品としては、ＳｉＯ₂微粒子表面のシラノール基にエチレングリコール、プロピレングリコール、１，４−ブタンジオール、ポリエチレングリコール類、グリセロール、トリメチロールプロパンのような多価アルコール、或いは、アルコキシシランをエーテル結合させたものがある。アミノ基を有する製品としては、ＳｉＯ₂微粒子表面のシラノール基に、エタノールアミンのような水酸基含有アミンをエーテル結合させたものがある。
【０１４７】
このようにして、無機超微粒子の表面に、重合性官能基を有するモノマー、オリゴマー又はポリマー構造の部分を導入できる。無機超微粒子（Ｂ）が充分な硬化反応性を発現するためには、無機超微粒子（Ｂ）の粒子部分１００重量部当たり、その表面に導入された重合性官能基を有する部分（重合性官能基が粒子表面に直接結合している場合には、該重合性官能基そのもの）が１重量部以上の割合で存在していることが好ましい。なお、無機超微粒子（Ｂ）に結合している重合性官能基の量は、元素分析法により測定できる。
【０１４８】
また、無機超微粒子（Ｂ）の表面に存在する重合性官能基の導入部分は、数平均分子量が３００〜２００００の範囲にあることが好ましい。
【０１４９】
無機超微粒子（Ｂ）が、一粒子中に２個以上の電離放射線硬化性基及び／又は１個以上の熱硬化性極性基を有する場合には、架橋反応により十分な硬化性を示すので好ましい。
【０１５０】
無機超微粒子（Ｂ）が重合性官能基を有する場合には、当該無機超微粒子の配合割合は、コーティング組成物中にフッ素含有成分（ｂ）が実質的に配合されている限り特に限定されないが、フッ素含有成分を含むバインダー系、無機超微粒子及びその他の成分を含む固形分全量に対して、０．１〜９９．５重量％の広い範囲で調節することができる。ここで、コーティング組成物の固形分とは溶剤以外の全ての成分であり、液状のモノマー及びオリゴマーも固形分に含まれる。
【０１５１】
無機超微粒子（Ｂ）が重合性官能基を有する場合には、本発明のコーティング組成物を硬化させる時に、バインダー成分だけでなく無機超微粒子も共有結合を形成するので、無機超微粒子を多量に配合しても塗膜は脆くなりにくく、成膜性を維持することができる。
【０１５２】
コーティング組成物中の無機超微粒子（Ｂ）は、フッ素含有成分の屈折率低下作用に全く又は僅かしか影響しない少量でも塗膜を引き締める効果が充分に得られるが、引き締め効果が不充分な場合には必要に応じて比較的多量に配合することができる。また、無機超微粒子の配合割合が大きくなると、コーティング組成物中のフッ素含有成分が希釈されてフッ素含有成分による屈折率低下作用が減弱してくるが、その替わりに、塗膜中にミクロボイドが形成されるようになり、当該ミクロボイドの作用によって塗膜の屈折率が低下して空気の屈折率に近づいていくので、フッ素含有成分とミクロボイドの協調によって低い屈折率が得られる。
【０１５３】
コーティング組成物中の無機超微粒子の配合割合が固形分全量に対して５０重量％以下の範囲では塗膜中にミクロボイドは通常形成されず、主にフッ素含有成分の作用によって塗膜の屈折率を低くすることができる。コーティング組成物中の無機超微粒子の配合割合が固形分全量に対して５０重量％を超えると、コーティング組成物の組成にもよるが塗膜中にミクロボイドが形成されるようになり、フッ素含有成分及びミクロボイド両方の作用により塗膜の屈折率を低くすることができる。コーティング組成物中の無機超微粒子の配合割合が固形分全量に対して７５重量％以上になると、フッ素含有成分の作用が残ってはいるが、ミクロボイドの屈折率低下作用が相対的に強くなる。
【０１５４】
このように、コーティング組成物中の無機超微粒子の配合割合が高くなると、フッ素含有成分による塗膜の屈折率低下作用は減弱するが、当該フッ素含有成分が塗膜の屈折率低下に貢献し、無機超微粒子がフッ素含有成分による塗膜の硬度及び強度の低下を阻止することには変わりない。
【０１５５】
本発明に係るコーティング組成物は、必須成分として、上記フッ素含有成分（ａ）及び上記無機超微粒子（Ｂ）を含有するが、さらに必要に応じて、上記したようなフッ素含有成分（ａ）以外のバインダー成分のほかにも、塗工液に調製するための溶剤、重合開始剤、硬化剤、架橋剤、紫外線遮断剤、紫外線吸収剤、表面調整剤（レベリング剤）、或いは、その他の成分を配合しても良い。
【０１５６】
重合開始剤は、本発明において必ずしも必要ではない。しかし、フッ素含有成分（ａ）、無機超微粒子（Ｂ）、及び、任意成分である他のバインダー成分の電離放射線硬化性基が、電離放射線照射によって直接重合反応を生じにくい場合がある。このような場合には、バインダー成分及び無機超微粒子の反応形式に合わせて、適切な開始剤を用いるのが好ましい。
【０１５７】
例えば、フッ素含有成分（ａ）が電離放射線硬化性基であるエチレン性不飽和結合を有する場合には、光ラジカル重合開始剤を用いる。光ラジカル重合開始剤としては、例えば、アセトフェノン類、ベンゾフェノン類、ケタール類、アントラキノン類、チオキサントン類、アゾ化合物、過酸化物、２，３−ジアルキルジオン化合物類、ジスルフィド化合物類、チウラム化合物類、フルオロアミン化合物などが用いられる。より具体的には、１−ヒドロキシ−シクロヘキシル−フェニル−ケトン、２−メチル−１［４−（メチルチオ）フェニル］−２−モルフォリノプロパン−１−オン、ベンジルジメチルケトン、１−（４−ドデシルフェニル）−２−ヒドロキシ−２−メチルプロパン−１−オン、２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オン、１−（４−イソプロピルフェニル）−２−ヒドロキシ−２−メチルプロパン−１−オン、ベンゾフェノン等を例示できる。これらのうちでも、１−ヒドロキシ−シクロヘキシル−フェニル−ケトン、及び、２−メチル−１［４−（メチルチオ）フェニル］−２−モルフォリノプロパン−１−オンは、少量でも電離放射線の照射による重合反応を開始し促進するので、本発明において好ましく用いられる。これらは、いずれか一方を単独で、又は、両方を組み合わせて用いることができる。これらは市販品にも存在し、例えば、１−ヒドロキシ−シクロヘキシル−フェニル−ケトンはイルガキュアー１８４（Irgacure 184）の商品名でチバスペシャリティーケミカルズ（株）から入手できる。
【０１５８】
光ラジカル重合開始剤を用いる場合には、フッ素含有成分を主体とするバインダー成分の合計１００重量部に対して、光ラジカル重合開始剤を通常は３〜１５重量部の割合で配合する。
【０１５９】
硬化剤は、フッ素含有成分（ｂ）、及び、任意成分である他のバインダー成分の熱硬化性極性基の熱硬化反応を促進するために配合される。熱硬化性極性基が水酸基である場合には、硬化剤として、通常、メチロールメラミン等の塩基性基を有する化合物、金属アルコキシド等の加水分解により水酸基を発生する加水分解性基を有する化合物が用いられる。
【０１６０】
塩基性基としては、アミン、ニトリル、アミド、イソシアネート基が好ましく用いられ、加水分解性基としては、アルコキシ基が好ましく用いられるが、後者の場合は、特に、下記式（４）で表されるアルミニウム化合物とその誘導体が水酸基との相性が良く、特に好ましく用いられる。
【０１６１】
ＡｌＲ₃ ・・・（４）
（式中、Ｒは、同一であっても異なっていてもよく、ハロゲン、炭素数１０以下、好ましくは４以下のアルキル、アルコキシ、アリルオキシ又はヒドロキシであり、これらの基は全部又は一部がキレート配位子により置き換えられていても良い。）
上記式（４）で表される化合物は、アルミニウム化合物、及び／又はそこから誘導されるオリゴマー、及び／又は錯体や無機又は有機酸のアルミニウム塩の中から選定することができる。具体的には、アルミニウム−ｓｅｃ−ブトキシド、アルミニウム−ｉｓｏ−プロポキシド、及び、そのアセチルアセトン、アセト酢酸エチル、アルカノールアミン類、グリコール類、及び、それらの誘導体との錯体等を挙げることができる。
【０１６２】
また、フッ素含有成分（ａ）又は他のバインダー成分の熱硬化性極性基がエポキシ基である場合には、コーティング組成物中に、硬化剤として、通常、多価カルボン酸無水物、又は、多価カルボン酸を用いる。
【０１６３】
多価カルボン酸無水物の具体例としては、無水フタル酸、無水イタコン酸、無水コハク酸、無水シトラコン酸、無水ドデセニルコハク酸、無水トリカルバリル酸、無水マレイン酸、無水ヘキサヒドロフタル酸、無水ジメチルテトラヒドロフタル酸、無水ハイミック酸、無水ナジン酸などの脂肪族または脂環族ジカルボン酸無水物；１，２，３，４−ブタンテトラカルボン酸二無水物、シクロペンタンテトラカルボン酸二無水物などの脂肪族多価カルボン酸二無水物；無水ピロメリット酸、無水トリメリット酸、無水ベンゾフェノンテトラカルボン酸などの芳香族多価カルボン酸無水物；エチレングリコールビストリメリテイト、グリセリントリストリメリテイトなどのエステル基含有酸無水物を挙げることができ、特に好ましくは、芳香族多価カルボン酸無水物を挙げることができる。また、市販のカルボン酸無水物からなるエポキシ樹脂硬化剤も好適に用いることができる。
【０１６４】
また、本発明に用いられる多価カルボン酸の具体例としては、コハク酸、グルタル酸、アジピン酸、ブタンテトラカルボン酸、マレイン酸、イタコン酸などの脂肪族多価カルボン酸；ヘキサヒドロフタル酸、１，２−シクロヘキサンジカルボン酸、１，２，４−シクロヘキサントリカルボン酸、シクロペンタンテトラカルボン酸などの脂肪族多価カルボン酸、およびフタル酸、イソフタル酸、テレフタル酸、ピロメリット酸、トリメリット酸、１，４，５，８−ナフタレンテトラカルボン酸、ベンゾフェノンテトラカルボン酸などの芳香族多価カルボン酸を挙げることができ、好ましくは芳香族多価カルボン酸を挙げることができる。
【０１６５】
硬化剤を用いる場合には、フッ素含有成分を主体とするバインダー成分の合計１００重量部に対して、硬化剤を通常は０．０５〜３０．０重量部の割合で配合する。
【０１６６】
架橋剤は、フッ素含有成分（ａ）を含むバインダー成分の分子同士、バインダー成分と無機超微粒子（Ｂ）の間、及び、無機超微粒子（Ｂ）同士の架橋反応を促進するための成分である。例えば、フッ素含有成分（ａ）の熱硬化性極性基が水酸基の場合には、上述したアルミニウムキレートが好ましく用いられる。
【０１６７】
フッ素含有成分として液状のフッ素含有モノマー及び／又はオリゴマーを比較的多量に用いる場合には、当該フッ素含有モノマー及び／又はオリゴマーが塗工液に調製するための液状媒体としても機能し得るので、溶剤を用いなくてもコーティング組成物の固形成分を溶解、分散、又は希釈して塗工液の状態に調製できる場合がある。従って、本発明において溶剤は必ずしも必要ではないが、固形成分を溶解分散し、濃度を調整して、塗工適性に優れた塗工液を調製するために溶剤を使用する場合が多い。
【０１６８】
本発明のコーティング組成物の固形成分を溶解分散するために用いる溶剤は特に制限されず、種々の有機溶剤、例えば、イソプロピルアルコール、メタノール、エタノール等のアルコール類；メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン等のケトン類；酢酸エチル、酢酸ブチル等のエステル類；ハロゲン化炭化水素；トルエン、キシレン等の芳香族炭化水素；或いはこれらの混合物を用いることができる。
【０１６９】
本発明においては、ケトン系の有機溶剤を用いるのが好ましい。本発明に係るコーティング組成物をケトン系溶剤を用いて調製すると、基材表面に容易に薄く均一に塗布することができ、且つ、塗工後において溶剤の蒸発速度が適度で乾燥むらを起こし難いので、均一な薄さの大面積塗膜を容易に得ることができる。
【０１７０】
反射防止膜の支持層であるハードコート層にアンチグレア層としての機能を付与するために当該ハードコート層の表面を微細凹凸に形成し、その上に、中屈折率層又は高屈折率層を介して又は介さずに本発明に係るコーティング組成物を塗布して低屈折率層を形成する場合がある。本発明に係るコーティング組成物をケトン系溶剤を用いて調製すると、このような微細凹凸の表面にも均一に塗工することができ、塗工むらを防止できる。
【０１７１】
ケトン系溶剤としては、１種のケトンからなる単独溶剤、２種以上のケトンからなる混合溶剤、及び、１種又は２種以上のケトンと共に他の溶剤を含有しケトン溶剤としての性質を失っていないものを用いることができる。好ましくは、溶剤の７０重量％以上、特に８０重量％以上を１種又は２種以上のケトンで占められているケトン系溶剤が用いられる。
【０１７２】
また、溶剤の量は、各成分を均一に溶解、分散することができ、調製後の保存時に凝集を来たさず、且つ、塗工時に希薄すぎない濃度となるように適宜調節する。この条件が満たされる範囲内で溶剤の使用量を少なくして高濃度のコーティング組成物を調製し、容量をとらない状態で保存し、使用時に必要分を取り出して塗工作業に適した濃度に希釈するのが好ましい。本発明においては、固形分と溶剤の合計量を１００重量部とした時に、全固形分０．５〜５０重量部に対して、溶剤を５０〜９５．５重量部、さらに好ましくは、全固形分１０〜３０重量部に対して、溶剤を７０〜９０重量部の割合で用いることにより、特に分散安定性に優れ、長期保存に適したコーティング組成物が得られる。
【０１７３】
上記各成分を用いて本発明に係るコーティング組成物を調製するには、塗工液の一般的な調製法に従って分散処理すればよい。例えば、各必須成分及び各所望成分を任意の順序で混合し、得られた混合物にビーズ等の媒体を投入し、ペイントシェーカーやビーズミル等で適切に分散処理することにより、コーティング組成物が得られる。
【０１７４】
こうして得られたコーティング組成物は、少なくとも、
（Ａ）分子中に電離放射線で硬化する官能基及び熱硬化する極性基の一方又は両方を持つフッ素含有成分（ａ）を含む１種又は２種以上のバインダー成分からなり、全体として電離放射線で硬化する官能基及び熱硬化する極性基の両方を含有するバインダー系、及び、
（Ｂ）塗工液に調製するための液状媒体中にコロイド状の形態で分散させることが可能で且つサブミクロンオーダーの無機超微粒子を含有してなるものである。
【０１７５】
このコーティング組成物は、保存用の高濃度の時には、無機超微粒子がコロイド状に分散していなくても良いが、溶剤又は液状のフッ素含有モノマー及び／又はオリゴマーの量を増量して塗工可能な最終濃度に調整した時には、塗工液中でコロイド状の形態で均一に分散する。
【０１７６】
本発明に係るコーティング組成物を塗工可能な最終濃度に調整することにより、フッ素含有成分（ａ）を含むバインダー系（Ａ）を含有すると共に、無機超微粒子（Ｂ）がコロイド状に分散してなる液状のコーティング組成物が得られる。
【０１７７】
この液状のコーティング組成物は、液状媒体として溶剤を用いる場合には、当該溶剤中に、フッ素含有成分（ａ）を含むバインダー系（Ａ）が溶解又は分散している共に、サブミクロンオーダーの無機超微粒子（Ｂ）がコロイド状に分散してなる形態をとる。
【０１７８】
また、バインダー成分として液状のフッ素含有モノマー及び／又はオリゴマーを用い、溶剤を用いない場合には、当該バインダー成分であるフッ素含有モノマー及び／又はオリゴマーからなる液状媒体中に、サブミクロンオーダーの無機超微粒子（Ｂ）がコロイド状に分散してなる形態をとる。
【０１７９】
被塗工体の表面に対してコーティング組成物に充分な密着性を付与するためには、極性基を有するフッ素含有成分（ａ）及びそれ以外の極性基を有するバインダー成分の量を調節し、コーティング組成物中に存在する熱硬化性極性基の量を、電離放射線硬化性基と熱硬化性極性基の総量を１００モル％とした時に５〜８０モル％とするのが好ましい。コーティング組成物中に存在する熱硬化性極性基の量が多いほど密着性は向上するが、その量が多くなり過ぎると、コーティング組成物中に含有される電離放射線硬化性基の量が相対的に少なくなるため、塗膜の硬度、強度の向上が期待できなくなる、或いは、電離放射線硬化による高速硬化が不可能となり生産性が落ちるといった不都合が生じる。また、熱硬化性極性基の量が多過ぎる場合には、コーティング組成物の塗工液中でバインダー成分と無機超微粒子との水素結合が多く形成される結果、ゲル化を起こすおそれがある。
【０１８０】
このコーティング組成物は、例えば、スピンコート法、ディップ法、スプレー法、スライドコート法、バーコート法、ロールコーター法、メニスカスコーター法、フレキソ印刷法、スクリーン印刷法、ビードコーター法等の各種方法で基材等の支持体上に塗布することができる。
【０１８１】
本発明のコーティング組成物を塗布する支持体は特に制限されない。好ましい基材としては、例えば、ガラス板；トリアセテートセルロース（ＴＡＣ）、ポリエチレンテレフタレート（ＰＥＴ）、ジアセチルセルロース、アセテートブチレートセルロース、ポリエーテルサルホン、アクリル系樹脂；ポリウレタン系樹脂；ポリエステル；ポリカーボネート；ポリスルホン；ポリエーテル；トリメチルペンテン；ポリエーテルケトン；（メタ）アクリロニトリル等の各種樹脂で形成したフィルム等を例示することができる。基材の厚さは、通常２５μｍ〜１０００μｍ程度であり、好ましくは５０μｍ〜１９０μｍである。
【０１８２】
コーティング組成物の塗工液を基材等の被塗工体の表面に直接、或いは、ハードコート層や光透過性の防眩層等の他の層を介して塗布し、乾燥させることによって、熱硬化性を有する極性基の作用により被塗工体表面に対する密着性に優れた塗膜が得られる。
【０１８３】
また、この塗布の際に、本発明に係るコーティング組成物は、塗工適性に優れ、被塗工体の表面に、容易に薄く広く且つ均一に塗布することができるので、均一な大面積薄膜を形成できる。特に、ケトン系溶剤を用いると蒸発速度が適度で、塗膜の乾燥むらが生じ難いので、均一な大面積薄膜を特に形成しやすい。
【０１８４】
得られた塗膜を、オーブン等の加熱手段を必要に応じて使用して乾燥し、電離放射線を照射すると、電離放射線硬化性基の作用により硬化し、屈折率が非常に低く、実用に耐え得る硬度及び強度を有し、且つ、透明性にも優れた塗膜が得られる。無機超微粒子（Ｂ）が電離放射線硬化性基を有する場合には、塗膜に電離放射線を照射する時にフッ素含有成分（Ａ）と無機超微粒子（Ｂ）が共有結合を形成し、塗膜がさらに強固になる。
【０１８５】
本発明において、コーティング組成物の塗膜を熱硬化させることは必須ではないが、塗膜を所定温度以上に加熱することにより熱硬化性極性基も直接、或いは、硬化剤等を介して架橋結合を形成するので、塗膜を熱硬化させることによって、硬度及び強度をさらに向上させることができる。無機超微粒子（Ｂ）が、フッ素含有成分と同様に熱硬化性極性基を有する場合には、熱硬化反応時にフッ素含有成分（Ａ）と無機超微粒子（Ｂ）が共有結合するので、塗膜がさらに強固になる。
【０１８６】
なお、コーティング組成物中のフッ素含有成分（Ａ）又は無機超微粒子（Ｂ）の少なくとも一方、好ましくは両方が、電離放射線硬化性基又は熱硬化性極性基を２つ以上有する場合には、塗膜を硬化させることによって、フッ素含有ポリマー同士、無機超微粒子同士、及びフッ素含有ポリマーと無機超微粒子相互の間に架橋構造を有する塗膜が形成される。
【０１８７】
このようにして得られた塗膜は、サブミクロンオーダーの無機超微粒子がフッ素を含有する硬化バインダー中に均一に混合されてなるものであるが、好ましくは、フッ素含有成分や同時に加えるフッ素非含有成分と無機超微粒子とが共有結合した構造を有しており、さらに必要に応じてその他の成分を含有している。
【０１８８】
この塗膜は、硬化したバインダーが無機超微粒子（Ｂ）の凝集力と硬さによって引き締められることによって、充分な膜硬度と膜強度が付与されているので、バインダーのフッ素含有率が高い場合でも、実用上耐え得る硬度と強度を有している。硬化しているバインダーと無機超微粒子とが共有結合することによって、膜硬度と膜強度はさらに向上する。塗膜のバインダーが架橋構造を形成し、好ましくは塗膜のバインダーと共に無機超微粒子も架橋構造を形成している場合には、膜硬度、膜強度、耐久性などの諸物性が特に優れているので好ましい。さらに、金属酸化物微粒子のサイズはサブミクロンオーダーなので、塗膜の透明性にも優れている。
【０１８９】
本発明によって得られる塗膜は、フッ素を多量に含有していて屈折率が非常に低く、実用に耐え得る硬度及び強度を有し、且つ、透明性にも優れており、さまざまな用途の光学薄膜として利用することができ、特に反射防止膜の低屈折率層として好適に利用することができる。
【０１９０】
本発明によれば、塗膜の屈折率が１．４５以下でありながら、又は、塗膜中に含まれるフッ素原子の数が、当該塗膜中に含まれる炭素原子の数と同量以上でありながら、充分な硬度及び強度を有する塗膜が得られる。なお、塗膜中のフッ素及び炭素夫々の原子数は、元素分析法で測定することができる。
【０１９１】
本発明によれば、基材上に直接又は他の層を介して膜厚が０．０５〜０．３μｍの塗膜を形成した時に、屈折率を１．４５以下に調節し、且つ、ＪＩＳ−Ｋ７３６１−１に規定されるヘイズ値が前記基材だけのヘイズ値と変わらないか又は前記基材だけのヘイズ値との差が０．１％以内になるように抑制することができる。
【０１９２】
また、本発明によれば、基材上に直接又は他の層を介して膜厚が０．０５〜０．３μｍの塗膜を形成した時に、屈折率を１．４５以下に調節し、且つ、スチールウールの＃００００番を用いて膜表面を２０回擦ることによりヘイズの変化が認められる荷重値を１Ｋｇ以上とすることができ、非常に低い屈折率、高い透明性、及び、実用上耐え得る硬度及び強度を兼ね備えた塗膜が得られる。
【０１９３】
また、本発明によれば、基材上に直接又は他の層を介して膜厚が０．０５〜０．３μｍの塗膜を形成した時に、屈折率が１．４５以下で、且つ、スチールウールの＃００００番を用いて２００ｇ荷重で膜表面を２０回擦る前後のヘイズの変化を５％以下とすることができ、非常に低い屈折率、高い透明性、及び、実用上耐え得る硬度及び強度を兼ね備えた塗膜が得られる。
【０１９４】
次に、本発明に係る塗膜を適用した反射防止膜の具体例について説明する。本発明に係る塗膜は、光透過性を有し、且つ、二層以上積層する場合には互いに屈折率の異なる層（光透過層）を一層以上積層してなる単層型又は多層型反射防止膜のうちの一層を形成するのに用いることができ、特に低屈折率層として好適であり、反射防止膜の最外層を形成するのに用いられる。なお、本発明においては、多層型反射防止膜の中で最も屈折率の高い層を高屈折率層と称し、最も屈折率の低い層を低屈折率層と称し、それ以外の中間的な屈折率を有する層を中屈折率層と称する。
【０１９５】
反射防止膜で被覆する面、例えば画像表示装置の表示面に、本発明に係る塗膜をただ一層設けただけでも、被覆面自体の屈折率と本発明に係る塗膜の屈折率のバランスが丁度良い場合には反射防止効果が得られる。従って、本発明に係る塗膜は、単層の反射防止膜としても有効に機能する場合がある。
【０１９６】
本発明に係る塗膜は、特に、液晶表示装置（ＬＣＤ）や陰極管表示装置（ＣＲＴ）、プラズマディスプレイパネル（ＰＤＰ）、エレクトロルミネッセンスディスプレイ（ＥＬＤ）等の画像表示装置の表示面を被覆する多層型反射防止膜の少なくとも一層、特に低屈折率層を形成するのに好適に用いられる。
【０１９７】
図１は、本発明に係る塗膜を光透過層として含んだ多層型反射防止膜により表示面を被覆した液晶表示装置の一例（１０１）の断面を模式的に示したものである。液晶表示装置１０１は、表示面側のガラス基板１の一面にＲＧＢの画素部２（２Ｒ、２Ｇ、２Ｂ）とブラックマトリックス層３を形成してなるカラーフィルター４を準備し、当該カラーフィルターの画素部２上に透明電極層５を設け、バックライト側のガラス基板６の一面に透明電極層７を設け、バックライト側のガラス基板とカラーフィルターとを、透明電極層５、７同士が向き合うようにして所定のギャップを空けて対向させ、周囲をシール材８で接着し、ギャップに液晶Ｌを封入し、背面側のガラス基板６の外面に配向膜９を形成し、表示面側のガラス基板１の外面に偏光フィルム１０を貼り付け、後方にバックライトユニット１１を配置したものである。
【０１９８】
図２は、表示面側のガラス基板１の外面に貼り付けた偏光フィルム１０の断面を模式的に示したものである。表示面側の偏光フィルム１０は、ポリビニルアルコール（ＰＶＡ）等からなる偏光素子１２の両面をトリアセチルセルロース（ＴＡＣ）等からなる保護フィルム１３、１４で被覆し、その裏面側に接着剤層１５を設け、その鑑賞側にハードコート層１６と多層型反射防止膜１７を順次形成したものであり、接着剤層１５を介して表示面側のガラス基板１に貼着されている。
【０１９９】
ここで、液晶表示装置等のように内部から射出する光を拡散させて眩しさを低減させるために、ハードコート層１６は、当該ハードコート層の表面を凹凸形状に形成したり或いは当該ハードコート層に無機や有機のフィラーを分散させて表面に凹凸形状を付与した防眩層（アンチグレア層）としてもよい。また、ハードコート層１６は有機や無機のフィラーを分散させることにより内部拡散性を持つ層としても良い。ハードコート層は二層以上の多層で構成しても良く、前記ハードコート層を適宜組み合わせて用いることができる。
【０２００】
多層型反射防止膜１７の部分は、バックライト側から鑑賞側に向かって中屈折率層１８、高屈折率層１９、低屈折率層２０が順次積層された３層構造を有している。多層型反射防止膜１７は、高屈折率層１９又は中屈折率層１８と低屈折率層２０が順次積層された２層構造であってもよい。なお、ハードコート層１６の表面が凹凸形状に形成される場合には、その上に形成される多層型反射防止膜１７も図示のように凹凸形状となる。また、高屈折率層１９や中屈折率層１８がハードコート性を有し、ハードコート層を兼ねる場合もある。
【０２０１】
低屈折率層２０は、高屈折率層１９の上に本発明に係るコーティング組成物を塗布し、乾燥し、光硬化させて形成した塗膜であり、屈折率を１．４６以下、好ましくは１．４１以下とすることができ、１．２０程度まで下げることが可能である。また、中屈折率層１８及び高屈折率層１９は、化学蒸着法（ＣＶＤ）や物理蒸着法（ＰＶＤ）などの蒸着法により形成した酸化チタンや酸化ジルコニウムのような屈折率の高い無機酸化物の蒸着膜としたり、或いは、酸化チタンのような屈折率の高い無機酸化物微粒子を分散させた塗膜とすることができ、中屈折率層１８には屈折率１．４６〜１．８０の範囲の光透過層、高屈折率層１９には屈折率１．６５以上の光透過層が使用される。
【０２０２】
さらに、帯電防止性或いは静電性を付与する必要がある場合には、導電性層を基材フィルム上に設けてもよく、また、ハードコート層中に導電性粒子を含有させてもよく、更にまた、中屈折率層や高屈折率層に分散させる屈折率の高い無機酸化物微粒子自体に導電性を有するものを用いることによっても同様の特性を得ることができる。更に、導電性を有する上記いずれかの層を２種以上組み合わせてもよい。
【０２０３】
この反射防止膜の作用により、外部光源から照射された光の反射率が低減するので、景色や蛍光燈の映り込みが少なくなり、表示の視認性が向上する。また、外光がディスプレイ表面に映り込んだり、眩しく光ったりする状態であるのを、ハードコート層１６の凹凸による光散乱効果によって外光の反射光が軽減し、表示の視認性がさらに向上する。
【０２０４】
液晶表示装置１０１の場合には、偏光素子１２と保護フィルム１３、１４からなる積層体に屈折率を１．４６〜１．８０の範囲で調節した中屈折率層１８と屈折率を１．６５以上に調節した高屈折率層１９を形成し、さらに本発明に係るコーティング組成物を塗布して低屈折率層２０を設けることができる。そして、反射防止膜１７を含む偏光フィルム１０を接着剤層１５を介して鑑賞側のガラス基板１上に貼着することができる。
【０２０５】
これに対し、ＣＲＴの表示面には配向板を貼着しないので、反射防止膜を直接設ける必要がある。しかしながら、ＣＲＴの表示面に本発明に係るコーティング組成物を塗布するのは煩雑な作業である。このような場合には、本発明に係る塗膜を含んでいる反射防止フィルムを作製し、それを表示面に貼着すれば反射防止膜が形成されるので、表示面に本発明に係るコーティング組成物を塗布しなくて済む。
【０２０６】
光透過性を有する基材フィルムの一面又は両面に直接或いは他の層を介して、光透過性を有し、且つ、屈折率が調節された光透過層を一層以上積層し、二層以上積層する場合には互いに屈折率が異なる２種類以上の光透過層を積層した組み合わせとし、当該光透過層のうちの少なくとも一つを本発明に係る塗膜で形成することにより、反射防止フィルムが得られる。基材フィルム及び光透過層は、反射防止フィルムの材料として使用できる程度の光透過性を有する必要があり、できるだけ透明に近いものが好ましい。
【０２０７】
図３は、本発明に係る塗膜を含んだ反射防止フィルムの一例（１０２）の断面を模式的に示したものである。反射防止フィルム１０２は、光透過性を有する基材フィルム２１の一面側に、高屈折率層２２を形成し、さらに当該高屈折率層の上に本発明に係るコーティング組成物を塗布して低屈折率層２３を設けたものである。この例では、互いに屈折率の異なる光透過層は高屈折率層と低屈折率層の二層だけだが、光透過層を三層以上設けてもよい。その場合には、低屈折率層だけでなく中屈折率層も、本発明に係るコーティング組成物を塗布して形成することができる。
【０２０８】
【実施例】
（実施例Ａ）
（実施例Ａ１：コーティング組成物の調製）
熱硬化性極性基を持つフッ素含有ポリマーと、電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素非含有多官能アクリレートとを組み合わせたコーティング組成物を調製した。
【０２０９】
水酸基含有熱硬化型フッ素含有ポリマーである商品名オプスターＪＮ７２１７（ジェイエスアール（株）製；固形分３重量％；屈折率１．４０；ＪＳ−１溶液）１０．０重量部に、ペンタエリスリトールトリアクリレート（日本化薬（株）製）０．１重量部を溶解した後、コロイダルシリカ（商品名ＭＩＢＫ−ＳＴ；日産化学（株）製；固形分３０重量％；一次粒子径１０ｎｍ；メチルイソブチルケトン溶液）０．６７重量部を加えて混合し、さらに、光重合開始剤として商品名イルガキュア１８４（チバスペシャリティーケミカルズ（株）製）０．０２重量部、及び、熱重合用硬化剤として商品名ＡＬＣＨ−ＴＲ（川研ファインケミカルズ（株）製）０．０２重量部を溶解して、コーティング組成物を得た。バインダー成分とコロイダルシリカの重量比は２：１だった。
【０２１０】
（実施例Ａ２：コーティング組成物の調製）
電離放射線硬化性基を持つフッ素含有ポリマーと、電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素非含有多官能アクリレートとを組み合わせたコーティング組成物を調製した。
【０２１１】
電離放射線硬化型フッ素含有成分である商品名オプスターＪＭ５０１０（ジェイエスアール（株）製；固形分１０重量％；屈折率１．４１；メチルエチルケトン溶液）１０．０重量部に、ペンタエリスリトールトリアクリレート（日本化薬（株）製）０．２重量部を溶解した後、コロイダルシリカ（商品名ＭＩＢＫ−ＳＴ；日産化学（株）製；固形分３０重量％；一次粒子径１０ｎｍ；メチルイソブチルケトン溶液）２重量部を加えて混合し、さらに、光重合開始剤として商品名イルガキュア１８４（チバスペシャリティーケミカルズ（株）製）０．０６重量部を溶解して、コーティング組成物を得た。バインダー成分とコロイダルシリカの重量比は２：１だった。
【０２１２】
（実施例Ａ３：コーティング組成物の調製）
電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素含有ポリマーと、電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素非含有多官能アクリレートとを組み合わせたコーティング組成物を調製した。
【０２１３】
（Ａ３−１）フッ素ポリマーの合成
ＣＨ₂＝ＣＦＣＯＯＣＨ₂（ＣＦ₂）₅ＣＨ₂ＯＨの１０重量％トリクロロトリフルオロエタン溶液５０重量部を冷却管を取り付けたガラス容器に入れ、開始剤のアゾビソイソブチロニトリル ０．２重量部を溶解して、窒素雰囲気下で８０℃で２４時間攪拌して重合反応を行った。２４時間後、低沸点物を減圧留去して、無色透明のポリマー４．５ｇを得た。
【０２１４】
得られたポリマーをテトラヒドロフランに溶解して得られた溶液（固形分：１０重量％）３０重量部に、２−メタクリロイルオキシエチルイソシアネート ０．８重量部を添加し、室温で３時間反応させることで、ポリマーの水酸基の一部にメタクリロイル基を導入した。
【０２１５】
３時間後、反応溶液をヘキサンで洗浄することで未反応物を除去し、電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素含有ポリマーを得た。このポリマーのＧＣＰ法によるポリスチレン換算の数平均分子量は約３０，０００であった。
【０２１６】
（Ａ３−２）コーティング組成物の調製
得られた上記フッ素含有ポリマーの１０重量％メチルイソブチルケトン溶液１０重量部に、ペンタエリスリトールトリアクリレート（日本化薬（株）製）０．２重量部を溶解した後、コロイダルシリカ（商品名ＭＩＢＫ−ＳＴ；日産化学（株）製；固形分３０重量％；一次粒子径１０ｎｍ；メチルイソブチルケトン溶液）２重量部を加えて混合し、さらに、光重合開始剤として商品名イルガキュア１８４（チバスペシャリティーケミカルズ（株）製）０．０６重量部を溶解して、コーティング組成物を得た。バインダー成分とコロイダルシリカの重量比は２：１だった。
【０２１７】
（比較例Ａ１：コーティング組成物の調製）
コロイダルシリカを添加しなかったことを除き、実施例Ａ１と同様の組成及び手順でコーティング組成物を得た。
【０２１８】
（比較例Ａ２：コーティング組成物の調製）
コロイダルシリカを添加しなかったことを除き、実施例Ａ２と同様の組成及び手順でコーティング組成物を得た。
【０２１９】
（比較例Ａ３：コーティング組成物の調製）
実施例Ａ１において、コロイダルシリカの代わりに、非コロイド状のシリカ超微粒子（商品名アエロジルＲ９７１、日本アエロジル（株）製）０．２重量部の分散体を用いたことを除き、実施例Ａ１と同様にしてコーティング組成物を得た。得られたコーティング組成物を用いて塗膜を形成したが、顔料の凝集により透明な塗膜が得られなかったため、後述する屈折率、反射率、その他の測定はできなかった。
【０２２０】
（実施例Ａ４：単層型反射防止膜の作製）
（Ａ４−１）透明ハードコート層の形成
トリアセチルセルロース基材上に、以下の組成からなるハードコート用塗工液（Ａ４−１）をバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させて、膜厚４μｍの透明ハードコート層を形成し、ハードコート基材Ａ４−１を得た。
＜ハードコート用塗工液（Ａ４−１）＞
・ペンタエリスリトールテトラアクリレート：２０．０重量部
・光重合開始剤（商品名イルガキュア１８４；チバスペシャリティーケミカルズ（株）製）：１．０重量部
・メチルイソブチルケトン：８０重量部
（Ａ４−２）防眩性付与ハードコート層の形成
トリアセチルセルロース基材上に、以下の組成からなるハードコート用塗工液（Ａ４−２）をバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させて、膜厚４μｍの透明ハードコート層を形成し、防眩性付与ハードコート基材Ａ４−２を得た。
＜ハードコート用塗工液（Ａ４−２）＞
・ペンタエリスリトールテトラアクリレート：３０．０重量部
・セルロースアセテートプロピオネート：０．４重量部
・ポリスチレンビーズペースト（商品名ＳＸ−１３０、綜研化学（株）製）：１０．０重量部
・光重合開始剤（商品名イルガキュア１８４；チバスペシャリティーケミカルズ（株）製）：１．０重量部
・メチルイソブチルケトン：７２．０重量部
（Ａ４−３）低屈折率層の形成
実施例Ａ１、Ａ２、Ａ３及び比較例Ａ１、Ａ２、Ａ３のコーティング組成物を、前記工程で作製したハードコート基材Ａ４−１及びＡ４−２のハードコート層上にバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させた後、８０℃で１時間加熱して低屈折率層を形成し、反射防止膜の形成された反射防止フィルムＡ４−３ａ、Ａ４−３ｂを得た。当該低屈折率層の膜厚は、分光光度計（島津製作所（株）製）で反射率を測定した時に５５０ｎｍ付近に最低反射率が来るように設定した。
【０２２１】
（実施例Ａ５：単層型反射防止膜の作製）
上記実施例Ａ４と同様の手法で、実施例Ａ１乃至Ａ３のコーティング組成物を、前記ハードコート基材Ａ４−１及びＡ４−２のハードコート層上に塗布し、乾燥後、ＵＶ照射を行って硬化させた。その後、加熱硬化を施さなかった以外は、実施例Ａ４と同様の手法で低屈折率層を形成し、反射防止膜の形成された反射防止フィルムＡ５−３ａ、Ａ５−３ｂを得た。
【０２２２】
（評価方法）
以下に示す各評価を行った。評価結果を第１表及び第２表に示す。
【０２２３】
（１）塗膜の屈折率
実施例Ａ１、Ａ２、Ａ３及び比較例Ａ１、Ａ２、Ａ３のコーティング組成物をシリコンウエハー上にスピンコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて５００ｍＪの照射量で硬化させた後、８０℃で１時間加熱して、膜厚０．１μｍの塗膜を得た。この塗膜の屈折率を、分光エリプソメーター（ＵＶＩＳＥＬ；ジョバンイーボン社製）を用い、ヘリウムイオンレーザー光の波長６３３ｎｍで測定した。
【０２２４】
（２）塗膜中のフッ素原子数と炭素原子数の比（Ｆ／Ｃ比）
イギリス VG Scientific社製のＸ線光電子分光装置ESCALAB 220i-XLを用いる元素分析法により、以下の測定条件で上記（１）で得られた塗膜中のフッ素原子（Ｆ）と炭素原子（Ｃ）の比率を測定した。
＜装置の設定＞
・Ｘ線源：Ａｌ Ｋα（モノクロ比）
・Ｘ線出力：２００Ｗ（１０ｋＶ、２０ｍＡ）
・使用レンズ：Ｌａｒｇｅ Ａｒｅａ ＸＬ
・帯電中和：電子中和銃、＋４Ｖ、中和補助マスク使用（Ａｌ導電性テープ）
・光電子脱出角度：９０°（試料法線）
・測定室内真空度：約３．０×１０^-7Ｐａ
・試料表面クリーニング：Ａｒ⁺ イオンエッチング
＜測定条件＞
ナロースキャンスペクトル法を用いた。
ａ）Ｃ １ｓ軌道
・測定エネルギー範囲：２７５〜２９５ｅＶ（総合エネルギーの範囲）
・測定点数：２０１点
・ステップサイズ：０．１０ｅＶ
・スキャン回数：７回
・パスエネルギー：２０ｅＶ
ｂ）Ｆ １ｓ軌道
・測定エネルギー範囲：６７５〜６９５ｅＶ（総合エネルギーの範囲）
・測定点数：２０１点
・ステップサイズ：０．１０ｅＶ
・スキャン回数：５回
・パスエネルギー：２０ｅＶ
＜Ｆ／Ｃ比の決定＞
測定範囲内に含まれるＦとＣの強度比によりＦ／Ｃ比を決定した。
【０２２５】
（３）反射率
反射防止フィルムＡ４−３ａ及びＡ４−３ｂの反射率を、分光光度計（島津製作所（株）製）で測定した。
【０２２６】
（４）ヘイズ
反射防止フィルムＡ４−３ａ及びＡ４−３ｂのヘイズを、濁度計（ＮＤＨ２０００；日本電色工業（株）製）で測定した。
【０２２７】
（５）膜硬度
反射防止フィルムＡ４−３ａ及びＡ４−３ｂ、更に反射防止フィルムＡ５−３ａ及びＡ５−３ｂの表面を、スチールウールの＃００００番を用いて２００〜１ｋｇ荷重で２０回擦り、ヘイズが変化した時の荷重値を検出した。
【０２２８】
【表１】

【０２２９】
【表２】

【０２３０】
（実施例Ｂ）
（実施例Ｂ１：コーティング組成物の調製）
電離放射線硬化性基を持つフッ素含有ポリマーと、電離放射線硬化性基及び熱硬化性極性基を併せ持つフッ素非含有多官能アクリレートと、重合性基を有するコロイダルシリカを組み合わせたコーティング組成物を調製した。
【０２３１】
電離放射線硬化型フッ素含有ポリマーである商品名オプスターＪＭ５０１０（ジェイエスアール（株）製；固形分１０重量％；屈折率１．４１；メチルイソブチルケトン溶液）１０．０重量部に、ペンタエリスリトールトリアクリレート（日本化薬（株）製）０．２重量部を溶解した後、重合性基を有するコロイダルシリカ（商品名Highlink OG108；クラリアントジャパン（株）製；シリカ：モノマー成分＝３０：７０（重量比）；モノマー種：トリプロピレングリコールジアクリレート）６．０重量部を加えて混合し、さらに、光重合開始剤として商品名イルガキュア１８４（チバスペシャリティーケミカルズ（株）製）０．０２重量部、及び、熱重合用硬化剤として商品名ＡＬＣＨ−ＴＲ（川研ファインケミカルズ（株）製）０．０２重量部を溶解して、コーティング組成物を得た。
【０２３２】
重合性基を有するコロイダルシリカである商品名Highlink OG108は、モノマー中にコロイダルシリカが分散されており、そのモノマーの一部がコロイダルシリカにグラフトしている製品である。グラフトしているモノマー量は、コロイダルシリカの１０重量％以上である。また、バインダー成分とシリカの比は、フッ素含有成分とHighlink OG108の合計量と、Highlink OG108のシリカ量の比であらわされ、３：１（バインダー成分：シリカ）であった。
【０２３３】
（実施例Ｂ２）
（Ｂ２−１）反応性超微粒子の調製
コロイダルシリカ（商品名ＭＩＢＫ−ＳＴ；日産化学（株）製；固形分３０重量％；一次粒子径１０ｎｍ；メチルイソブチルケトン溶液）１０重量部に、γ‐アクリロキシプロピルトリメトキシシラン（ＫＢＭ５１０３；信越化学工業（株）製）０．１重量部、酢酸０．０１重量部を添加し、８０℃で１２時間、加熱攪拌することで、上記シランカップリング剤の一部をコロイダルシリカ上に共有結合させた。
【０２３４】
（Ｂ２−２）コーティング組成物の調製
得られた反応性コロイダルシリカ（熱重量分析法により３００℃まで昇温させて残った固形分は３４重量％）１．１８重量部を、実施例１で用いたのと同様のフッ素含有成分（商品名オプスターＪＭ５０１０）１０．０重量部とペンタエリスリトールトリアクリレート（日本化薬（株）製）０．２重量部を溶解した溶液中に分散し、コーティング組成物を得た。バインダー成分とシリカの重量比は、３：１だった。
【０２３５】
（比較例Ｂ１）
実施例Ｂ１のフッ素系バインダー成分にコロイダルシリカを加えずに、そのままコーティング液として用いた。
【０２３６】
（比較例Ｂ２）
（比Ｂ２−１）非コロイド状反応性超微粒子の調製
非コロイド状のシリカ超微粒子（商品名アエロジルＲ９７１、日本アエロジル（株）製）１０重量部に、γ‐アクリロキシプロピルトリメトキシシラン（ＫＢＭ５１０３；信越化学工業（株）製）０．１重量部、酢酸０．０１重量部を添加し、８０℃で１２時間、加熱攪拌することで、上記シランカップリング剤の一部を非コロイド状シリカ超微粒子の上に共有結合させた。
【０２３７】
（比Ｂ２−２）コーティング組成物の調製
上記比Ｂ２−１で得られた非コロイド状反応性シリカ超微粒子の粉体３重量部をメチルイソブチルケトン７０重量部に分散させた。実施例Ｂ１で用いたフッ素含有成分（商品名オプスターＪＭ５０１０；ジェイエスアール（株）製）１０．０重量部に、ペンタエリスリトールトリアクリレート（日本化薬（株）製）０．２重量部を溶解した後、上記非コロイド状反応性シリカ超微粒子の分散液０．４重量部を加えて、コーティング組成物を得た。しかし、顔料の凝集により透明な塗膜が得られなかったため、後述する屈折率、反射率、その他の測定はできなかった。
【０２３８】
（実施例Ｂ３）
（Ｂ３−１）反応性超微粒子の調製
実施例Ｂ２で用いたのと同じコロイダルシリカ（商品名ＭＩＢＫ−ＳＴ）１０重量部に、ペンタエリスリトールトリアクリレート ０．１重量部を添加し、１２０℃で１時間、加熱還流することで、上記モノマーの一部をコロイダルシリカ上に固定させた。
【０２３９】
（Ｂ３−２）コーティング組成物の調製
実施例Ｂ１で用いたのと同様のフッ素含有成分（商品名オプスターＪＭ５０１０）１０．０重量部にペンタエリスリトールトリアクリレート ０．２重量部を溶解した後、上記の反応性コロイダルシリカ １．２９重量部を添加し、コーティング組成物を得た。バインダー成分とシリカの重量比は、３：１だった。
【０２４０】
（実施例Ｂ４：単層型反射防止膜の作製）
（Ｂ４−１）透明ハードコート層の形成
トリアセチルセルロース基材上に、以下の組成からなるハードコート用塗工液（Ｂ４−１）をバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させて、膜厚４μｍの透明ハードコート層を形成し、ハードコート基材Ｂ４−１を得た。
＜ハードコート用塗工液（Ｂ４−１）＞
・ペンタエリスリトールテトラアクリレート：２０．０重量部
・光重合開始剤（商品名イルガキュア１８４；チバスペシャリティーケミカルズ（株）製）：１．０重量部
・メチルイソブチルケトン：８０重量部
（Ｂ４−２）防眩性付与ハードコート層の形成
トリアセチルセルロース基材上に、以下の組成からなるハードコート用塗工液（Ｂ４−２）をバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させて、膜厚４μｍの透明ハードコート層を形成し、防眩性付与ハードコート基材Ｂ４−２を得た。
＜ハードコート用塗工液（Ｂ４−２）＞
・ペンタエリスリトールテトラアクリレート：３０．０重量部
・セルロースアセテートプロピオネート：０．４重量部
・ポリスチレンビーズペースト（商品名ＳＸ−１３０、綜研化学（株）製）：１０．０重量部
・光重合開始剤（商品名イルガキュア１８４；チバスペシャリティーケミカルズ（株）製）：１．０重量部
・メチルイソブチルケトン：７２．０重量部
（Ｂ４−３）低屈折率層の形成
実施例Ｂ１乃至Ｂ３、実施例Ａ２、比較例Ｂ１及びＢ２のコーティング組成物を、前記工程で作製したハードコート基材Ｂ４−１及びＢ４−２のハードコート層上にバーコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて３００ｍＪの照射量で硬化させた後、８０℃で１時間加熱して低屈折率層を形成し、反射防止膜の形成された反射防止フィルムＢ４−３ａ、Ｂ４−３ｂを得た。当該低屈折率層の膜厚は、分光光度計（島津製作所（株）製）で反射率を測定した時に５５０ｎｍ付近に最低反射率が来るように設定した。
【０２４１】
（実施例Ｂ５：単層型反射防止膜の作製）
上記実施例Ｂ４と同様の手法で、実施例Ｂ１乃至Ｂ３のコーティング組成物を、前記ハードコート基材Ｂ４−１及びＢ４−２のハードコート層上に塗布し、乾燥後、ＵＶ照射を行って硬化させた。その後、加熱硬化を施さなかった以外は、実施例Ａ４と同様の手法で低屈折率層を形成し、反射防止膜の形成された反射防止フィルムＢ５−３ａ、Ｂ５−３ｂを得た。
【０２４２】
（評価方法）
以下に示す各評価を行った。評価結果を第３表及び第４表に示す。なお、実施例Ｂ１乃至Ｂ３で用いられる反応性超微粒子による効果を非反応性超微粒子と比較するために、実施例Ａ２のコーティング組成物（非反応性コロイダルシリカを含有している）についても評価を行なった。
【０２４３】
（１）塗膜の屈折率
実施例Ｂ１乃至Ｂ３、実施例Ａ２、比較例Ｂ１及びＢ２のコーティング組成物を、シリコンウエハー上にスピンコーターで塗布し、溶剤を乾燥後、ＵＶ照射装置（フュージョンＵＶシステムズジャパン（株）製）のＨバルブを光源に用いて５００ｍＪの照射量で硬化させた後、８０℃で１時間加熱して、膜厚０．１μｍの塗膜を得た。この塗膜の屈折率を、分光エリプソメーター（ＵＶＩＳＥＬ；ジョバンイーボン社製）を用い、ヘリウムイオンレーザー光の波長６３３ｎｍで測定した。
【０２４４】
（２）反射率
反射防止フィルムＢ４−３ａ及びＢ４−３ｂの反射率を、分光光度計（島津製作所（株）製）で測定した。
【０２４５】
（３）ヘイズ
反射防止フィルムＢ４−３ａ及びＢ４−３ｂのヘイズを、濁度計（ＮＤＨ２０００；日本電色工業（株）製）で測定した。
【０２４６】
（４）膜硬度
反射防止フィルムＢ４−３ａ及びＢ４−３ｂ、更に反射防止フィルムＢ５−３ａ及びＢ５−３ｂの表面を、スチールウールの＃００００番を用いて５０〜１ｋｇ荷重で２０回擦り、ヘイズの変化が５％を超える時の荷重値を検出した。
【０２４７】
【表３】

【０２４８】
【表４】

【０２４９】
【発明の効果】
以上に述べたように、本発明に係るコーティング組成物は、電離放射線硬化性基及び熱硬化性官能基の少なくとも一方を有するフッ素含有成分（ａ）を主体とし、全体として電離放射線硬化性基及び熱硬化性極性基の両方を含有するバインダー系が溶解、分散していると共に、サブミクロンオーダーのサイズである無機超微粒子がコロイド状態で分散している塗工液の形態に調製することができる。
【０２５０】
フッ素含有バインダーは屈折率が低い材料なので、屈折率の低い塗膜を形成できる。しかし、フッ素含有バインダーからなる塗膜は、原子間力が小さいフッ素原子を含有しているため硬度及び強度が不足し易い。これに対して、本発明のコーティング組成物を用いて塗膜を形成すると、当該塗膜は電離放射線の照射により硬化させることができることに加えて、硬化したフッ素含有バインダー中にコロイド状態で分散している無機超微粒子の凝集力及び硬さによって塗膜が引き締められるので、屈折率を下げるためにバインダー成分のフッ素含有量を非常に大きくした場合でも当該塗膜の硬度及び強度の著しい低下を避けることができる。
【０２５１】
また、本発明のコーティング組成物中にコロイド状態で分散し得る無機超微粒子は、フッ素含有成分の屈折率低下作用及び成膜性に全く又は僅かしか影響しない少量で、塗膜を引き締める効果が充分に得られ、屈折率を上げたり膜を脆くするような量を配合する必要はない。無機超微粒子は、サブミクロンオーダーのサイズなので、透明性にも優れている。
【０２５２】
さらに、本発明のコーティング組成物のバインダー系は熱硬化性極性基を含有しているので、該コーティング組成物を用いて形成した塗膜は、熱硬化性極性基の極性基としての作用によって被塗布面に対する密着性に優れている。また、この塗膜を熱硬化させた場合には、電離放射線硬化と熱硬化の２つの硬化反応によって、架橋密度を高めることができ、さらに塗膜の硬度及び強度を向上させることができる。
【０２５３】
従って、本発明に係るコーティング組成物を用いることによって、フッ素含有率が大きくて屈折率が非常に低く、実用に耐え得る硬度及び強度を有し、密着性及び透明性にも優れた塗膜が得られる。
【０２５４】
また、本発明によれば、上記コーティング組成物を用いる塗布法によって上記の塗膜を作成できるので、塗膜の量産性に優れている。
【０２５５】
本発明に係る塗膜は、上記本発明に係るコーティング組成物を用いて作成されるものであり、電離放射線で硬化させたフッ素含有バインダー中に無機超微粒子がコロイド状態で分散した構造を有している。この塗膜は、上述したところから明らかなように、屈折率が非常に低く、実用に耐え得る硬度及び強度を有し、密着性及び透明性に優れ、量産性にも優れている。この塗膜は、低い屈折率が求められる光学薄膜、なかでも特に反射防止膜の低屈折率層として好適に用いられる。
【０２５６】
そして、本発明に係る塗膜を含んでいる反射防止膜は、液晶表示装置やＣＲＴ等の表示面に好適に適用される。
【図面の簡単な説明】
【図１】本発明に係る塗膜を含んだ多層型反射防止膜により表示面を被覆した液晶表示装置の一例であり、その断面を模式的に示した図である。
【図２】本発明に係る塗膜を含んだ多層型反射防止膜を設けた配向板の一例であり、その断面を模式的に示した図である。
【図３】本発明に係る塗膜を含んだ反射防止フィルムの一例であり、その断面を模式的に示した図である。
【符号の説明】
１０１…液晶表示装置
１０２…反射防止フィルム
１…表示面側のガラス基板
２…画素部
３…ブラックマトリックス層
４…カラーフィルター
５、７…透明電極層
６…背面側のガラス基板
８…シール材
９…配向膜
１０…偏光フィルム
１１…バックライトユニット
１２…偏光素子
１３、１４…保護フィルム
１５…接着剤層
１６…ハードコート層
１７…多層型反射防止膜
１８…中屈折率層
１９…高屈折率層
２０…低屈折率層
２１…基材フィルム
２２…高屈折率層
２３…低屈折率層[0001]
BACKGROUND OF THE INVENTION
The present invention is a coating composition capable of forming a fluorine-containing coating film having a low refractive index, high hardness and high adhesion, and low refractive index, high hardness, high adhesion, high transparency, In addition, the present invention relates to an optical thin film that is excellent in mass productivity and requires a low refractive index, and particularly relates to a coating film suitably used as a low refractive index layer of an antireflection film.
[0002]
The present invention also relates to an antireflection film having an optical thin film layer formed using the coating composition, and an antireflection film and an image display device to which such an antireflection film is applied.
[0003]
[Prior art]
A display surface of an image display device such as a liquid crystal display (LCD) or a cathode ray tube display device (CRT) is required to have less reflection of light emitted from an external light source such as a fluorescent lamp in order to improve its visibility. .
[0004]
It has been known that the reflectance is reduced by coating the surface of a transparent object with a transparent film having a low refractive index, and an antireflection film using such a phenomenon is provided on the display surface of the image display device. It is possible to improve visibility. The antireflection film is a single layer structure in which a low refractive index layer having a low refractive index is provided on the display surface, or a medium to high refractive index layer is provided on the display surface to further improve the antireflection effect. Or a multi-layer structure in which a low refractive index layer for reducing the refractive index of the outermost surface is provided on the middle to high refractive index layer.
[0005]
The single-layer type antireflection film has a simple layer structure as compared with the multilayer type, and is excellent in productivity and cost performance. On the other hand, the multilayer type antireflection film can improve the antireflection performance by combining the layer structures, and can easily achieve higher performance than the single layer type.
[0006]
The method of forming a low refractive index layer contained in such an antireflection film is generally roughly divided into a vapor phase method and a coating method. The vapor phase method includes a physical method such as a vacuum deposition method and a sputtering method, and a CVD method. The coating method includes a roll coating method, a gravure coating method, a slide coating method, a spray method, a dipping method, a screen printing method, and the like.
[0007]
In the case of the vapor phase method, it is possible to form a high-performance and high-quality transparent thin film, but it is necessary to precisely control the atmosphere in a high vacuum system, and a special heating device or ion generation acceleration device Therefore, there is a problem that the manufacturing cost is inevitably increased because the manufacturing apparatus is complicated and large. Further, in the case of the vapor phase method, it is difficult to increase the area of the transparent thin film or to form the transparent thin film with a uniform thickness on the surface of a film having a complicated shape.
[0008]
On the other hand, in the case of the spray method among the application methods, there are problems such as poor utilization efficiency of the coating liquid and difficulty in controlling the film forming conditions. In the case of roll coating method, gravure coating method, slide coating method, dipping method, screen printing method, etc., the utilization efficiency of film forming raw material is good, and there are advantages in mass production and equipment cost, but generally The transparent thin film obtained by the coating method has a problem that its function and quality are inferior to those obtained by the vapor phase method.
[0009]
As a coating method, a coating liquid containing a polymer containing a fluorine atom in its molecular structure (fluorine-containing polymer) is applied to the surface of the support and dried, or a monomer containing a fluorine atom in the molecular structure. It is known that a coating liquid containing (fluorine-containing monomer) is applied to the surface of a support, dried, and then cured by UV irradiation to form a low refractive index layer. A coating film made of a binder containing fluorine has a low refractive index, and the refractive index decreases as the fluorine content increases. Further, when the fluorine content of the coating film is increased, there is an effect that dirt is difficult to adhere and the antifouling property is improved. However, since the intermolecular force of fluorine itself is small, molecules containing fluorine atoms tend to be soft, and there is a problem that the hardness and strength of the coating film decrease when the fluorine content in the coating film increases.
[0010]
In principle, the low refractive index layer is often provided on or near the outermost surface of the antireflection film. Therefore, the low refractive index layer is inherently susceptible to attacks such as contact, collision or friction with any article, and increases the refractive index of the coating film. For this reason, if the fluorine content is too high, the hardness will be significantly reduced and the film will be easily damaged, and even if it is rubbed strongly to wipe off dust and dirt, it may be damaged.
[0011]
In addition, when the low refractive index layer is provided as an intermediate layer near the surface, it is slightly damaged against external attack, but the fluorine content is increased to increase the refractive index of the coating film. If the thickness is too high, the strength is also reduced, so that the stress is likely to cause peeling at the interface between the low refractive index layer and the adjacent layer.
[0012]
By mixing a binder having a high fluorine content with a fluorine-free binder having a high hardness or strength to form a low refractive index layer, the hardness and strength of the low refractive index layer can be improved. However, in this case, since the fluorine content in the entire low refractive index layer is low, the effect of lowering the refractive index by the fluorine-containing binder is impaired, and the refractive index cannot be lowered sufficiently.
[0013]
Japanese Patent Application Laid-Open No. 2000-64601 discloses a low refractive index layer having a very fine porous structure formed by forming microvoids having an average diameter of 200 nm or less in a coating film made of a fluorine-containing polymer. The low refractive index layer disclosed in this publication can make the refractive index of the coating film close to the refractive index of air (ie, refractive index 1) by forming a large number of microvoids in the coating film. The refractive index can be lowered without increasing the fluorine content of the polymer. However, even in this case, if the amount of microvoids is excessively increased in order to lower the refractive index of the coating film, the hardness and strength of the coating film are reduced as in the case of increasing the fluorine content.
[0014]
[Problems to be solved by the invention]
The present invention has been accomplished in view of the above-mentioned actual situation, and a first object thereof is to provide a coating composition capable of forming a fluorine-containing coating film having a low refractive index, high hardness and high adhesion. It is in.
[0015]
The second object of the present invention is to use a coating composition that can achieve the first object, with a low refractive index, high hardness, high adhesion, high transparency, and a coating method. Therefore, it is possible to form a coating film that is excellent in mass productivity.
[0016]
The third object of the present invention is to use the coating composition that can achieve the first object, and has a low refractive index, high hardness, high adhesion, high transparency, and mass productivity. It is to provide an optical thin film that is excellent and has a low refractive index, and in particular, a coating film suitably used as a low refractive index layer of an antireflection film.
[0017]
The fourth object of the present invention is to provide an antireflection film having an optical thin film layer comprising a coating film capable of achieving the second or third object, and an antireflection film to which such an antireflection film is applied. The object is to provide a film and an image display device.
[0018]
The present invention solves at least one of these objects.
[0019]
[Means for Solving the Problems]
  The antireflection film for a liquid crystal display device according to the present invention has light transmittance directly on at least one side of a triacetyl cellulose base material or through at least one other layer, and is refracted with each other when two or more layers are laminated. One or more light-transmitting layers having different rates are laminated, and at least one of the light-transmitting layers has (A) one or both of a functional group cured by ionizing radiation and a thermosetting polar group in the molecule. A binder system comprising one or more binder components including a fluorine-containing component (a), and containing both a functional group that is cured by ionizing radiation and a polar group that is thermally cured as a whole, and (B) the surface An introduction part having a functional group that is cured by ionizing radiation and / or a polar group that is thermally cured is present in an amount of 1 part by weight or more per 100 parts by weight of the particle part, and A coating film obtained by curing a composition comprising inorganic ultrafine particles having a primary particle diameter of 1 to 500 nm, wherein the fluorine-containing component (a), the inorganic ultrafine particles, and the inorganic ultrafine particles Fine particles are covalently bonded by polymerization between functional groups that are cured by the ionizing radiation and / or polar groups that are thermally cured.
[0021]
By adjusting the coating composition according to the present invention to a final concentration at which coating is possible, the fluorine-containing component (a) is mainly used, and it contains both functional groups that are cured by ionizing radiation and polar groups that are thermally cured as a whole. A liquid coating composition containing a binder system and having inorganic ultrafine particles (B) dispersed in a colloidal form is obtained.
[0022]
Since the fluorine-containing binder is a material having a low refractive index, a coating film having a low refractive index can be formed. However, since a coating film made of a fluorine-containing binder contains fluorine atoms having a small atomic force, hardness and strength are likely to be insufficient. In contrast, when a coating film is formed using the coating composition of the present invention, the coating film can be cured by irradiation with ionizing radiation, and is dispersed in a colloidal state in the cured fluorine-containing binder. Since the coating film is tightened by the cohesive strength and hardness of the inorganic ultrafine particles, even if the fluorine content of the binder component is extremely increased to lower the refractive index, avoid a significant decrease in the hardness and strength of the coating film. be able to.
[0023]
In addition, the inorganic ultrafine particles that can be dispersed in a colloidal state in the coating composition of the present invention have a sufficient effect of tightening the coating film with a small amount that has no or little influence on the refractive index lowering action and film forming property of the fluorine-containing component. Therefore, it is not necessary to add an amount that increases the refractive index and makes the film brittle. Inorganic ultrafine particlesPrimary particle size is 1 to 500 nmSo it has excellent transparency.
[0024]
Furthermore, since the binder system of the coating composition of the present invention contains a thermosetting polar group, the coating film formed using the coating composition is covered by the action of the thermosetting polar group as a polar group. Excellent adhesion to the coated surface. Moreover, when this coating film is heat-cured, the crosslinking density can be increased by two curing reactions of ionizing radiation curing and thermosetting, and the hardness and strength of the coating film can be further improved.
[0025]
Therefore, the present inventionofBy using the coating composition, it is possible to obtain a coating film having a high fluorine content, a very low refractive index, hardness and strength that can withstand practical use, and excellent adhesion and transparency.
[0026]
Moreover, according to this invention, since said coating film can be created with the apply | coating method using the said coating composition, it is excellent in the mass-productivity of a coating film.
[0027]
In the present invention, the fluorine-containing component (a) is appropriately combined with other binder components as necessary to supplement the shortage of curing reactive groups.
[0028]
When a fluorine-containing component (a) having a functional group that is cured by ionizing radiation is used, a binder component having at least a thermosetting polar group in the molecule is combined. When a fluorine-containing component (a) having a polar group that is thermally cured is used, a binder component having at least a functional group that is cured by ionizing radiation in the molecule is combined.
[0029]
The fluorine-containing component (a) is preferably a fluorine-containing component (a ′) having both a functional group that is cured by ionizing radiation and a polar group that is thermally cured. Moreover, it is preferable that the other binder component combined with a fluorine-containing component (a) has both the functional group hardened | cured by ionizing radiation, and the polar group hardened | cured.
[0030]
In order to increase the crosslinking density of the coating film, it is preferable to use a combination of the fluorine-containing component (a) and the polyfunctional (meth) acrylate. Moreover, in order to make the refractive index of a coating film low, it is preferable that another binder component also has a fluorine atom.
[0031]
It is preferable that the thermosetting polar group of the fluorine-containing component (a) which is a main binder component in the present invention is a hydrogen bond forming group. When this thermosetting polar group is a hydrogen bond-forming group, not only the adhesion to the coating film but also the affinity with the inorganic ultrafine particles (B) is excellent, and the inorganic ultrafine particles (B) The colloidal dispersion of can be improved.
[0032]
The thermosetting polar group is particularly preferably a hydroxyl group among the hydrogen bond forming groups. When the thermosetting polar group is a hydroxyl group, a functional group excellent in affinity with inorganic ultrafine particles can be easily introduced, and at the same time, a crosslinking point can be introduced by treatment in the presence of heating or an appropriate curing agent. Can also be done easily.
[0033]
In order to sufficiently reduce the refractive index of the coating film, the refractive index of the fluorine-containing component is preferably 1.45 or less, or the hydrogen bonded to the carbon of all the binder components contained in the binder system. It is preferable that 5 mol% or more is substituted with a fluorine atom.
[0035]
Further, in order to avoid the adverse effect of adversely affecting the refractive index lowering effect by diluting the fluorine-containing component concentration by blending the inorganic ultrafine particles, the refractive index of the inorganic ultrafine particles (B) is preferably 1.60 or less.
[0036]
As a specific material of the inorganic ultrafine particles (B), it is preferable to use at least one fine particle selected from silica, alumina, magnesium fluoride and calcium fluoride.
[0037]
Hydrophobizing the surface of the inorganic ultrafine particles (B) is preferable because the dispersibility in a solvent or liquid monomer and / or oligomer can be improved and it can be easily dispersed in a colloidal form.
[0038]
On the surface of the inorganic ultrafine particles (B),Functional groups curable by ionizing radiation and / or polar groups curable by heatBy imparting, the covalent bond between the binder component and the inorganic ultrafine particles (B) can be increased, and the hardness and strength of the coating film can be intentionally improved. Of inorganic ultrafine particles (B)Functional groups curable by ionizing radiation and / or polar groups curable by heatIn general, the ionizing radiation curable group and / or thermosetting polar group may be the same as those of the binder component combined with the inorganic ultrafine particles (B).
[0040]
The inorganic ultrafine particles (B) are usually preferably used in the range of 0.1 to 70% by weight based on the solid content. However, when the inorganic ultrafine particles (B) have a polymerizable functional group, the inorganic ultrafine particles (B) are blended in the range of 0.1 to 99.5% by weight with respect to the total solid content of the coating composition. be able to. When the inorganic ultrafine particles (B) have a polymerizable functional group, not only the binder component but also the inorganic ultrafine particles form a covalent bond when the coating composition is cured. The film does not easily become brittle, and the film formability can be maintained.
[0041]
The present inventionofThe coating film is obtained by applying the coating composition to the surface of the object to be coated and curing it. In the fluorine-containing binder cured by cross-linking,Primary particle size is 1 to 500 nmThe inorganic ultrafine particles are dispersed.
[0042]
As is apparent from the above, this coating film has a very low refractive index, has a hardness and strength that can withstand practical use, is excellent in adhesion and transparency, and is excellent in mass productivity. This coating film is suitably used as an optical thin film for which a low refractive index is required, particularly as a low refractive index layer of an antireflection film.
[0043]
When the fluorine-containing binder constituting the coating film is cured by cross-linking, it is preferable because various physical properties such as film hardness, film strength, and durability are excellent. It is preferable that the inorganic ultrafine particles and the fluorine-containing binder in the coating film are covalently bonded, particularly crosslinked, by a curing reaction, because various physical properties such as film hardness, film strength, and durability are further improved.
[0044]
According to the present invention, a coating film having sufficient hardness and strength can be obtained while the refractive index is 1.45 or less.
[0045]
Furthermore, according to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed, the refractive index is adjusted to 1.45 or less, and the haze value specified in JIS-K7361-1 is set. It is possible to suppress the difference between the haze value of the base material alone or the difference between the haze value of the base material only and not more than 0.1%.
[0046]
Further, according to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed, the refractive index is adjusted to 1.45 or less, and steel film # 0000 is used to form the film surface. A coating film having a load value at which a change in haze is recognized is 1 kg or more can be formed by rubbing 20 times.
[0047]
Moreover, according to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed on the substrate, the refractive index is 1.45 or less, and # 0000 steel wool is used. The change in haze before and after rubbing the film surface 20 times with a load of 200 g can be reduced to 5% or less, and a coating film having extremely low refractive index, high transparency, and hardness and strength that can be practically used is obtained. It is done.
[0048]
And the antireflection film containing the coating film according to the present invention isLiquid crystal displayIt is suitably applied to the display surface.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below. In addition, the definition of the main words and phrases mentioned in this specification is as follows.
[0050]
That is, “(meth) acryl” represents acryl and methacryl, “(meth) acrylate” represents acrylate and methacrylate, and “(meth) acryloyl” represents acryloyl and methacryloyl.
[0051]
The “binder system” is a material system that imparts film forming properties and a three-dimensional form to the coating film, and also functions as a matrix that wraps and holds other components contained in the coating film. The binder system is composed of a single or a plurality of binder components, and may contain other components such as a polymerization initiator and a dispersing agent as required. When the binder component is fixed to the coated surface by solidification without chemical reaction or curing with chemical reaction of the binder component in the binder system, the binder system becomes a binder and a film is formed.
[0052]
The “binder component” is a component that can be solidified without a chemical reaction or can be cured with a chemical reaction of the binder component. When the binder component is fixed to the surface to be coated by such solidification or curing, the binder component becomes a film. When they are fixed to each other, a molded body is obtained. Relatively low molecular weight monomers and oligomers cannot function as binders unless they have cure reactivity, while relatively large molecular weight polymers and oligomers can be dried or dried without having cure reactivity. It becomes a film by cooling and solidification, and can function as a binder.
[0053]
“Fluorine-containing component” means a binder component having a fluorine atom in the molecule. The fluorine-containing component is not limited to the fluorine-containing component (a) described later. For example, it does not have any curing reactive groups such as functional groups that are cured by ionizing radiation or polar groups that are thermally cured, and therefore even a binder component that does not have curing reactivity has fluorine atoms in the molecule. If present, it corresponds to a fluorine-containing component.
[0054]
On the other hand, the “fluorine-free component” means a binder component having no fluorine atom in the molecule and may or may not have curing reactivity.
[0055]
Further, “curing reactivity” means chemical reactivity that causes a curing phenomenon of the binder component.
[0056]
Based on the above definitions, first, the coating composition according to the present invention will be described.
[0057]
The first coating composition according to the present invention is at least:
(A) Fluorine having one or both of a functional group curable with ionizing radiation (hereinafter referred to as “ionizing radiation curable group”) and a thermosetting polar group (hereinafter referred to as “thermosetting polar group”) in the molecule. A binder system comprising one or more binder components including the component (a), and containing both an ionizing radiation curable group and a thermosetting polar group as a whole; and
(B) A coating composition characterized in that it can be dispersed in a colloidal form in a liquid medium for preparing a coating solution, and contains inorganic sub-micron order particles.
[0058]
Moreover, the 2nd coating composition which concerns on this invention is prepared in the liquid form which can apply said 1st coating composition, (A) Ionizing radiation curable group and thermosetting in a molecule | numerator. Solvent binder system consisting of one or two or more binder components containing a fluorine-containing component (a) having one or both polar groups, and containing both ionizing radiation curable groups and thermosetting polar groups as a whole Or in a liquid medium composed of the liquid binder system (A), (B) submicron-order inorganic ultrafine particles are characterized by being colloidally dispersed, It is a coating composition.
[0059]
When the coating liquid of the coating composition is applied to the surface of the object to be coated, dried, and irradiated with ionizing radiation, the binder system of the coating composition contains a functional group that is cured by ionizing radiation. A chemical bond such as a cross-linked bond can be formed in the film, and the coating film can be cured. Accordingly, it is possible to prevent a decrease in hardness and strength of the coating film due to fluorine.
[0060]
Moreover, since this binder system has a polar group, the coating film formed using the coating liquid of this coating composition is excellent in the adhesiveness with respect to a support body. Furthermore, since the polar group of this binder system has both thermosetting properties, not only the effect of improving the adhesion of the coating film by the action as a polar group, but also the chemicals such as cross-linking by the action as a thermosetting group. It also has the effect of forming bonds and curing the coating. Therefore, if the coating film formed from the coating composition is thermally cured, a high crosslinking density can be obtained by two curing reactions of ionizing radiation curing and thermosetting, and the film hardness can be further improved. In addition, when the binder component constituting the binder system is a polymer composed of a chain of two or more monomer units, the functional group cured by ionizing radiation and the thermosetting polar group may be substituted at the end of the main chain. It may be substituted directly in the middle of the main chain, or may be substituted on a side chain branched from the main chain.
[0061]
The fluorine-containing component (a) blended in the coating composition of the present invention is a main binder component for imparting film formability (film forming ability) and a low refractive index to the coating composition.
[0062]
The fluorine-containing component (a) is not only a fluorine-containing component having a function of lowering the refractive index of the coating film, but also has an ionizing radiation curable group, and the hardness and strength of the coating film are reduced by fluorine. In addition, the film has a thermosetting polar group and exhibits a function of improving the adhesion to the coated surface, so that the physical properties of the coating film containing fluorine can be improved.
[0063]
When the fluorine-containing component (a) itself that causes the hardness or strength of the coating film to decrease is cured in the binder system by ionizing radiation, the effect of increasing the hardness and strength of the coating film is high. ) Preferably has at least an ionizing radiation curable group.
[0064]
The fluorine-containing component (a) is sufficient if it has either an ionizing radiation curable group or a thermosetting polar group, but the binder system as a whole is both an ionizing radiation curable group and a thermosetting polar group. It is necessary to exhibit both the function of preventing the hardness and strength of the coating film from being lowered by fluorine and the function of improving the adhesion to the coated surface. Therefore, if necessary, other binder components are appropriately combined with the fluorine-containing component (a) to supplement the shortage of curing reactive groups.
[0065]
For example, when the fluorine-containing component (a) has only an ionizing radiation curable group, or the fluorine-containing component (a) has an ionizing radiation curable group and a thermosetting polar group, the amount of the thermosetting polar group is When the amount is small, a binder component having at least a thermosetting polar group in the molecule is combined to supply the thermosetting polar group to the binder system.
[0066]
Conversely, when the fluorine-containing component (a) has only a thermosetting polar group, or the fluorine-containing component (a) has an ionizing radiation curable group and a thermosetting polar group, the amount of the ionizing radiation curable group In the case where the amount is low, the binder component having at least an ionizing radiation curable group in the molecule is combined to supply the ionizing radiation curable group to the binder system.
[0067]
In addition, when combining 2 or more types of binder components, you may use 2 or more types of fluorine-containing components (a) or another binder component.
[0068]
When the fluorine-containing component (a) is a fluorine-containing component having both an ionizing radiation curable group and a thermosetting polar group (hereinafter referred to as “fluorine-containing component (a ′)”), another binder Even if it does not combine a component, since an ionizing radiation-curable group and a thermosetting polar group can be supplied to a binder system, it is preferable. However, also in this case, when either or both of the ionizing radiation curable group and the thermosetting polar group are insufficient, the ionizing radiation curable group and the thermosetting polar group are used to supplement the shortage. Other binder components having one or both of these can be combined.
[0069]
In any case, the other binder component combined with the fluorine-containing component (a) is preferably a binder component having both an ionizing radiation curable group and a thermosetting polar group. In particular, when the fluorine-containing component (a) has only an ionizing radiation curable group or a thermosetting polar group, by combining other binder components having both an ionizing radiation curable group and a thermosetting polar group In addition to supplying insufficient curing reactive groups, since the fluorine-containing component (a) and other binder components can be cured by ionizing radiation or heat, the hardness and strength of the coating film are further improved.
[0070]
That is, when a fluorine-containing component (a) having only an ionizing radiation-curable group and another binder component having both an ionizing radiation-curable group and a thermosetting polar group are combined, the fluorine-containing component (a) is ionizing radiation-cured. The functional group is supplied to the binder system, the other binder component supplements the shortage of the thermosetting polar group, and the fluorine-containing component (a) and the other binder component can be cured by ionizing radiation.
[0071]
In addition, when the fluorine-containing component (a) having only a thermosetting polar group and another binder component having both an ionizing radiation curable group and a thermosetting polar group are combined, the fluorine-containing component (a) is thermosetting. A polar group is supplied to the binder system, the other binder component supplements the shortage of ionizing radiation curable groups, and the fluorine-containing component (a) and the other binder component can be thermally cured.
[0072]
Furthermore, when combining a fluorine-containing component (a) and another binder component, from a viewpoint of raising the fluorine content in a coating composition and a coating film, not only a fluorine-containing component (a) but other binder components Is preferably a fluorine-containing component.
[0073]
Specifically, selection or combination of binder components as shown below is preferable. (1) Fluorine-containing component (a ') having both an ionizing radiation curable group and a thermosetting polar group
(2) A combination of the fluorine-containing component (a ′) and the fluorine-containing component (a) having at least an ionizing radiation curable group
(3) A combination of the fluorine-containing component (a ′) and a fluorine-containing component (a) having at least a thermosetting polar group
(4) Combination of the fluorine-containing component (a ') and a fluorine-free component having both an ionizing radiation curable group and a thermosetting polar group
(5) Combination of a fluorine-containing component (a) having at least an ionizing radiation-curable group and a fluorine-free component having both an ionizing radiation-curable group and a thermosetting polar group
(6) A combination of a fluorine-containing component (a) having at least a thermosetting polar group and a fluorine-free component having both an ionizing radiation-curable group and a thermosetting polar group
By selecting or combining (1) to (6) above, a sufficient amount of ionizing radiation curable groups and thermosetting polar groups can be supplied to the binder system in a well-balanced manner. Further, (1) to (5) are preferable in that the fluorine-containing component (a) itself can be cured by ionizing radiation, and (2) in that the fluorine-containing component (a) and other binder components can be cured by ionizing radiation. (4) and (5) are preferable. Furthermore, (2) and (3) are preferable in that the other binder component also has a fluorine atom.
[0074]
The ionizing radiation curable group of the binder component is a functional group capable of causing a large molecular weight reaction such as polymerization or crosslinking by irradiation with ionizing radiation. For example, photo radical polymerization, photo cation polymerization, photo anion polymerization Such a polymerization reaction, or a reaction that proceeds by a reaction mode such as addition polymerization or condensation polymerization that proceeds through photodimerization can be mentioned. Among them, in particular, ethylenically unsaturated bonds such as acrylic group, vinyl group, and allyl group are directly photoradically polymerized by irradiation with ionizing radiation such as ultraviolet rays and electron beams, or indirectly by the action of an initiator. It is preferable because it causes a reaction and is relatively easy to handle including the photocuring step.
[0075]
Moreover, the thermosetting polar group of a binder component is a functional group which can advance large molecular weight reaction, such as superposition | polymerization or bridge | crosslinking, between the same polar groups or another functional group by heating. Among thermosetting polar groups, for example, hydrogen bond-forming groups such as hydroxyl groups, carboxyl groups, amino groups, and epoxy groups have not only adhesion to the coating film but also affinity with inorganic ultrafine particles (B). This is preferable because it is excellent and improves the colloidal dispersion of the inorganic ultrafine particles (B). Among the thermosetting polar groups, a hydroxyl group can easily introduce a functional group having excellent affinity with inorganic ultrafine particles such as a silanol (Si-OH) group, and at the same time, heating or presence of an appropriate curing agent. The treatment at the bottom is most preferable because the introduction of crosslinking points can be easily performed.
[0076]
When the fluorine-containing component (a) and other curing-reactive binder components have two or more ionizing radiation-curable groups and / or one or more thermosetting polar groups in one molecule, the crosslinking reaction It is preferable because it exhibits sufficient curability.
[0077]
As the fluorine-containing component (a), a monomer, an oligomer, a polymer, or these are arbitrarily selected from fluorine-containing compounds having one or both of an ionizing radiation curable group and a thermosetting polar group together with a fluorine atom in the molecular structure. A mixture in combination with can be selected and used.
[0078]
Among the fluorine-containing component (a), the fluorine-containing monomer and oligomer having an ionizing radiation curable group have a high effect of increasing the crosslinking density of the coating film, and are components having high fluidity due to their low molecular weight. There is also an effect of improving coating suitability.
[0079]
Furthermore, when a relatively large amount of liquid fluorine-containing monomer and oligomer is used as the fluorine-containing component (a), the fluorine-containing monomer and oligomer function as a diluting solvent, and other compounding components can be dissolved without using a solvent. Alternatively, it is possible to disperse and disperse the inorganic ultrafine particles in a colloidal form, and it is also possible to prepare a liquid coating composition containing no solvent.
[0080]
On the other hand, the fluorine-containing polymer of the fluorine-containing component (a) has a high molecular weight, and therefore has higher film formability than the fluorine-containing monomer and / or oligomer. Combining this fluorine-containing polymer with the above-mentioned fluorine-containing monomers and oligomers can improve the fluidity and thus improve the coating suitability, and also increase the crosslink density, thereby improving the hardness and strength of the coating film. it can.
[0081]
As the fluorine-containing component (a) having only an ionizing radiation curable group, fluorine-containing monomers having an ethylenically unsaturated bond can be widely used. More specifically, fluoroolefins (for example, fluoroethylene, vinylidene fluoride) , Tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.).
[0082]
Examples of the fluorine-containing component (a) having only a thermosetting polar group include 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer; fluoroethylene-hydrocarbon vinyl ether copolymer; epoxy, polyurethane, cellulose, phenol, Examples include fluorine-modified products of resins such as polyimide.
[0083]
As the fluorine-containing component (a ′) having both an ionizing radiation curable group and a thermosetting polar group, a fluorine-containing component having a polar group, which will be described later as a raw material for synthesizing the polymer or oligomer belonging to the fluorine-containing component (a), is used. What substituted a part of hydrogen of the containing monomer by the fluorine atom can be used. In particular, those in which a fluorine atom is introduced at the α-position of the ethylenically unsaturated bond are superior in lowering the refractive index and increasing the strength of the coating film, and therefore can be preferably used.
[0084]
For example, 1,1,2-trifluoroallyloxy monomer represented by the following formula 1
[0085]
[Chemical 1]

[0086]
Wherein -A is -CH₂OH, -COOCH_Three, -CN, or -COOH, especially -A is -CH.₂OH is preferable because it is excellent in solubility and soluble in solvents such as acetone, acetic acid, and tetrahydrofuran (THF). n is an integer, and an integer in the range of 1 to 3 is particularly preferable. )
However, it is suitably used as a fluorine-containing monomer having both an ionizing radiation curable group and a thermosetting polar group.
[0087]
In addition, examples of the fluorine-containing component (a ′) having both an ionizing radiation curable group and a thermosetting polar group include an acrylic or methacrylic acid moiety and a fully fluorinated alkyl, alkenyl, aryl ester (for example, the following formula 2 Or a compound represented by the following formula 3)
[0088]
[Chemical 2]

[0089]
(Wherein R¹Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a halogen atom. Rf represents a fully or partially fluorinated alkyl group, alkenyl group, heterocycle or aryl group. R²And R^ThreeEach independently represents a hydrogen atom, an alkyl group, an alkenyl group, a heterocyclic ring, an aryl group or a group defined by the above Rf. R¹, R², R^ThreeAnd Rf may each have a substituent other than a fluorine atom. R², R^ThreeAnd any two or more groups of Rf may be bonded to each other to form a ring structure. )
[0090]
[Chemical 3]

[0091]
(In the formula, B represents a fully or partially fluorinated n-valent organic group. R^FourRepresents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a halogen atom. R^FourMay have a substituent other than a fluorine atom. n represents an integer of 2 to 8. ),
Examples include fully or partially fluorinated vinyl ethers, fully or partially fluorinated vinyl esters, fully or partially fluorinated vinyl ketones, and the like.
[0092]
The oligomer or polymer used as the fluorine-containing component (a) is first a monomer or oligomer belonging to the fluorine-containing component (a ′) having both an ionizing radiation curable group and a thermosetting polar group, particularly preferably the above 1, By polymerizing a monomer or oligomer having only one ionizing radiation curable group such as an ethylenically unsaturated bond such as 1,2-trifluoroallyloxy monomer, it contains a fluorine atom and has a polar group. An intermediate polymer having a pendant structure is synthesized. The intermediate polymer may be a copolymer of a monomer or oligomer belonging to the fluorine-containing component (a) and a monomer or oligomer not belonging to the fluorine-containing component (a). A similar intermediate polymer can also be obtained by copolymerizing a fluorine-containing monomer having only an ionizing radiation-curable group and a fluorine-free monomer having both an ionizing radiation-curable group and a polar group.
[0093]
Here, as fluorine-free monomers having both ionizing radiation curable groups and polar groups, epoxy (meth) acrylates, glycidyl (meth) acrylates, glycerol mono (meth) acrylates, glycerol di (meth) acrylates, 2-hydroxyethyl (meth) acrylate and its caprolactone-modified product, 2-hydroxypropyl (meth) acrylate and its caprolactone-modified product, phosphoric acid (meth) acrylates, polyethylene glycol (meth) acrylates, polypropylene glycol (meth) acrylate And (meth) acrylates of polyethylene glycol-polypropylene glycol copolymers, succinic acid acrylates, acrylamide and the like.
[0094]
Then, when a compound having both a functional group capable of polycondensation and polyaddition to the polar group of the intermediate polymer and an ionizing radiation curable group such as an ethylenically unsaturated bond is reacted, the polar group of the intermediate polymer is reacted. An ionizing radiation curable group is introduced through a part, and an oligomer and a polymer belonging to the fluorine-containing component (a ′) having both an ionizing radiation curable group and a polar group are synthesized. The functional group capable of polycondensation or polyaddition with respect to the polar group of the intermediate polymer can be appropriately selected from those exemplified as the polar group of the intermediate polymer. In addition, when the fluorine atom is substituted to the residue part introduce | transduced with an ionizing-radiation-curable group into an intermediate polymer, since the refractive index of the oligomer or polymer obtained becomes still lower, it is preferable.
[0095]
The ratio of the amount of ionizing radiation-curable groups and the amount of polar groups (ionizing radiation-curable groups: polar groups) contained in the oligomer and polymer as the fluorine-containing component (a ′) is 20 mol%: 80 mol% to The range of 90 mol%: 10 mol% is preferable because the balance between ionizing radiation curability and adhesion to the support is well balanced.
[0096]
In this invention, although a fluorine-containing component (a) is used as an essential binder component, another binder component can be used with a fluorine-containing component (a) as needed. In order to control various properties such as improving the hardness, strength, adhesion, etc. of the coating film or adjusting the refractive index to a predetermined value, it does not contain fluorine without departing from the object of the present invention. A binder component may be used. As other binder components, non-reactive fluorine-free oligomers and polymers, non-reactive fluorine-containing oligomers and polymers, curing reactive fluorine-free monomers, oligomers and polymers can be used as appropriate.
[0097]
For example, non-reactive fluorine-free oligomers and polymers include transparent resins conventionally used to form optical thin films, such as polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyolefin, poly Examples thereof include non-curing reactive polymers having no polymerizable functional group such as styrene, polyamide, polyimide, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, and polycarbonate.
[0098]
Non-reactive fluorine-containing oligomers or polymers include, for example, polytetrafluoroethylene; 4-fluoroethylene-6-fluoropropylene copolymer; 4-fluoroethylene-ethylene copolymer; polyvinyl fluoride; polyvinylidene fluoride A fluorine-modified silicone resin and the like can be exemplified.
[0099]
In addition, examples of the curing reactive fluorine-free monomer, oligomer and polymer include monomers and oligomers having a polymerizable functional group such as an ethylenically unsaturated bond, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl. Monofunctional (meth) acrylates such as (meth) acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, carboxypolycaprolactone acrylate, acrylic acid, methacrylic acid, acrylamide; ethylene glycol diacrylate, pentaerythritol diacrylate monostea Diacrylate such as rate; Tri (meth) acrylate such as trimethylolpropane triacrylate and pentaerythritol triacrylate, pentaerythritol tetra Polyfunctional (meth) acrylates such as acrylate derivatives and dipentaerythritol pentaacrylate, or can be exemplified those radically polymerizable monomers are polymerized oligomer. Moreover, the curable reactive polymer which introduce | transduced polymerizable functional groups like an ethylenically unsaturated bond into the said non-curable reactive polymer can be illustrated. Further, a fluorine-free monomer having both an ionizing radiation curable group and a polar group as exemplified as a raw material for producing the intermediate polymer of the fluorine-containing component (a ′) can also be used.
[0100]
The other binder component preferably has an ionizing radiation curable group capable of forming a crosslink with the fluorine-containing component (a), particularly an ethylenically unsaturated bond. The monomer as another binder component preferably has two or more ionizing radiation curable groups such as ethylenically unsaturated bonds in one molecule, and among them, polyfunctional (meth) acrylate is preferable. Furthermore, in order to lower the refractive index of the coating film, it is preferable that other binder components also have fluorine atoms.
[0101]
The coating composition of the present invention has an SP value of 8.5 to 12 based on the SP value calculation formula proposed by Fedros in order to improve the compatibility of the fluorine-containing component and the inorganic ultrafine particles. You may mix | blend a fluorine-free monomer and / or oligomer. Even if the inorganic ultrafine particles are sufficiently dispersed and transparent in the state of the coating liquid, the inorganic ultrafine particles may be aggregated and whitened during the drying of the coating film. In contrast, the coating composition of the present invention is blended with a fluorine-free monomer and / or oligomer having a high affinity for both the fluorine-containing component and the inorganic ultrafine particles, thereby preventing whitening of the coating film. be able to.
[0102]
Here, as a fluorine-free monomer and / or oligomer having a bifunctional or higher ethylenically unsaturated bond and an SP value of 8.5 to 12, specifically, acrylic acid, methacrylic acid, acrylamide, etc. Monofunctional (meth) acrylates; diacrylates such as pentaerythritol triacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate monostearate; tri (meth) acrylates such as trimethylolpropane triacrylate and pentaerythritol triacrylate, pentaerythritol Examples include polyfunctional (meth) acrylates such as tetraacrylate derivatives and dipentaerythritol pentaacrylate, or oligomers obtained by polymerizing these radical polymerizable monomers. These fluorine-free monomers and / or oligomers may be used in combination of two or more.
[0103]
In order to uniformly apply the coating composition according to the present invention to a large area, it is preferable to use a ketone solvent or a mixture thereof as described later, but the SP value of the ketone solvent or a mixture thereof is also the above 8. When the non-fluorine-containing monomer or oligomer having the SP value in this range is used, the compatibility between the fluorine-containing component and the inorganic ultrafine particles is improved, and at the same time, the solvent of the coating composition There is also an effect of improving solubility in coating and coating suitability.
[0104]
The non-fluorine-containing monomer and / or oligomer for improving the compatibility between the fluorine-containing component and the inorganic ultrafine particles is usually about 0.1 to 70% by weight with respect to the total solid content in the coating composition of the present invention. Include in proportions.
[0105]
Crosslinking of film forming property, coating suitability, and ionizing radiation curing by appropriately combining monomers, oligomers and polymers belonging to the fluorine-containing component (a) and monomers, oligomers and polymers not belonging to the fluorine-containing component (a). Various properties such as density, fluorine content, and content of polar groups having thermosetting properties can be adjusted. For example, the crosslinking density and processability are improved by monomers and oligomers, and the film forming property of the coating composition is improved by polymers.
[0106]
In the present invention, a monomer having a number average molecular weight (polystyrene equivalent number average molecular weight measured by gel permeation chromatography (GPC)) of 2,000 or less from the fluorine-containing component (a), and a number average molecular weight of 2,000. Various properties of the coating film can be obtained by appropriately combining an oligomer having a molecular weight of 10,000 to 10,000 and a polymer having a number average molecular weight of 10,000 to 200,000, and further combining a binder component other than the fluorine-containing component (a) as necessary. Can be easily adjusted.
[0107]
In particular, by combining a polymer having a number average molecular weight of 10,000 to 200,000 belonging to the fluorine-containing component (a) and a polyfunctional (meth) acrylate having two or more ethylenically unsaturated bonds, coating suitability is achieved. It is preferable because various physical properties including film formability, film hardness, film strength and the like are easily balanced.
[0108]
In the present invention, the amount of fluorine contained in the entire binder component is determined by the amount of fluorine contained in the fluorine-containing component (a) and the fluorine-containing component other than the fluorine-containing component (a) to be blended in the coating composition. And the refractive index of the coating film obtained can be adjusted by controlling the fluorine content of the binder component which has a fluorine-containing component (A) as a main component. That is, the higher the fluorine content of the fluorine-containing component (a) or other fluorine-containing component to be blended in the coating composition or the greater the blending amount, the more the coating composition formed using the coating composition and the coating composition. Increases the fluorine content and decreases the refractive index. On the other hand, as the fluorine content of the fluorine-containing component (a) or other fluorine-containing component to be blended in the coating composition is lower or the blending amount is smaller, a coating film formed using the coating composition and the coating composition. The fluorine content is reduced and the refractive index is increased.
[0109]
In order to sufficiently reduce the refractive index of the coating film, the fluorine-containing component (a) preferably has a refractive index of 1.45 or less, particularly preferably 1.42 or less, and contains fluorine other than the fluorine-containing component (A). The refractive index of the component is also preferably 1.45 or less, particularly 1.42 or less. In terms of fluorine content, 5 mol% or more, particularly 20 mol% or more of hydrogen bonded to carbon of all binder components mainly composed of the fluorine-containing component (a) is substituted with fluorine atoms. Is preferred.
[0110]
However, if the fluorine content of the binder component becomes too large, the hardness and strength of the coating film formed from the coating composition containing the binder component will decrease, and it will be practical for use as an optical thin film such as a low refractive index layer. There is a problem that it becomes impossible. Conventionally, when the refractive index of the fluorine-containing component is about 1.42 or less, the fluorine content becomes too large, and it has been difficult to obtain a coating film having sufficient hardness and strength.
[0111]
On the other hand, in the present invention, as will be described later, carbon constituting the molecules of all binder components in the coating composition by blending inorganic ultrafine particles with the binder component mainly composed of the fluorine-containing component (a). Even when using 20% by mole or more of hydrogen atoms bonded to fluorine atoms substituted with fluorine atoms, or when using a fluorine-containing component having a refractive index of 1.42 or less, It is possible to form a coating film having strength. The fluorine substitution rate of the fluorine-containing component can be measured by NMR method or elemental analysis method.
[0112]
The inorganic ultrafine particles (B) blended in the coating composition of the present invention have a hardness that can withstand practically a coating film formed by a binder formed by curing a binder system (A) having a high fluorine content. It is a component for imparting strength.
[0113]
That is, a coating liquid in which inorganic ultrafine particles are colloidally dispersed in a binder system (A) mainly composed of a fluorine-containing component (a) is applied to the surface of an object to be coated and solidified by a method such as drying. Thereafter, by further ionizing radiation curing, a coating film in which the inorganic ultrafine particles are uniformly dispersed in the binder composed of the cured product of the binder system (A) is obtained. Since this coating film is tightened by the cohesive force of uniformly dispersed inorganic ultrafine particles and the hardness of the particles themselves, even if the fluorine content of the binder component is increased to lower the refractive index, the hardness and strength of the coating film. Can be avoided, and has a hardness and strength that can withstand practical use.
[0114]
Further, the inorganic ultrafine particles (B) that can be dispersed in a colloidal state in the coating composition of the present invention have absolutely no effect on the refractive index lowering and film-forming properties of the fluorine-containing component (a) and / or other fluorine-containing components. Alternatively, the effect of tightening the coating film can be sufficiently obtained with a small amount that has little influence, and it is not necessary to add an amount that increases the refractive index or makes the film brittle.
[0115]
The coating composition of the present invention is prepared from the beginning to a concentration used for coating work using a solvent, and is stored in a high concentration state containing no solvent or only a small amount, and the solvent is added immediately before use. May be adjusted to the concentration used for coating work. Further, by using a relatively large amount of a liquid fluorine-containing monomer and / or oligomer as a fluorine-containing component, the coating composition may be prepared in a coating liquid state without using a solvent. In any case, in the present invention, the inorganic ultrafine particles (B) are required to be finally dispersible in a colloidal form in the coating solution.
[0116]
Therefore, the inorganic ultrafine particles (B) are prepared in a solvent for preparing the coating composition of the present invention as a coating liquid, or prepared in a coating liquid without using a solvent. Therefore, the liquid fluorine-containing monomer and / or oligomer must be capable of being uniformly dispersed in a colloidal form.
[0117]
In the coating composition according to the present invention, it is possible to sufficiently improve the hardness and strength of the coating film only by adding a relatively small amount of inorganic ultrafine particles. It is possible to completely eliminate the adverse effects that adversely affect the refractive index lowering effect by diluting the refractory index or to a slight extent. However, when using a relatively large amount of inorganic ultrafine particles, there is no possibility of adversely affecting the refractive index lowering effect of the fluorine-containing component, so the inorganic ultrafine particles have a refractive index of 1.60 or less, In particular, those of 1.55 or less are preferably used. For example, alumina Al₂O_Three(Refractive index: 1.53), silica SiO₂(Refractive index 1.46), magnesium fluoride MgF₂(Refractive index 1.38), calcium fluoride CaF₂(Refractive index 1.36) and the like can be exemplified. Among them, as described above, it is preferable to select and use a colloidally dispersible solvent or monomer and / or oligomer. When a particularly low refractive index is required, colloidal silica (SiO 2) among the inorganic ultrafine particles exemplified above.₂It is preferable to use fine particles. In addition, when priority is given to imparting sufficient hardness to the coating film, alumina (Al₂O_ThreeIt is preferable to use fine particles.
[0118]
The inorganic ultrafine particles (B) are of a so-called ultrafine particle size in order to ensure sufficient transparency in the coating film. Here, “ultrafine particles” are particles of submicron order, and generally mean particles having a particle diameter smaller than particles having a particle diameter of several μm to several hundred μm, which are generally called “fine particles”. ing. The specific size of the inorganic ultrafine particles (B) used in the present invention varies depending on the use and grade of the optical thin film to which the coating composition of the present invention is applied, but generally the primary particle diameter is 1 nm. It is preferable to use one in the range of ˜500 nm. If the primary particle diameter is less than 1 nm, it is difficult to impart sufficient hardness and strength to the coating film. On the other hand, if the primary particle diameter exceeds 500 nm, the transparency of the coating film is impaired and cannot be applied depending on the application. It may become. The primary particle size of the inorganic ultrafine particles may be measured visually from the secondary electron emission image photograph obtained by a scanning electron microscope (SEM) or the like, or a dynamic light scattering method or a static light scattering method is used. Mechanical measurement may be performed with a particle size distribution meter or the like.
[0119]
Among the above-mentioned primary particle diameter ranges, the inorganic ultrafine particles (B) having a primary particle diameter of 1 to 100 nm are suitable for forming an ultrathin optical thin film such as a low refractive index layer of an antireflection film. The inorganic ultrafine particles (B) having a primary particle diameter of 100 to 500 nm are suitable for forming a relatively thick Mos-eye structure film among optical thin films.
[0120]
As long as the inorganic ultrafine particles can be dispersed in a colloidal form, the hardness and strength of the coating film can be ensured, and the transparency can be ensured with a size on the order of submicrons, the particle shape is spherical. Any shape can be used in the present invention.
[0121]
If a part of the inorganic ultrafine particles is a metal hydroxide and has a structure in which water is adsorbed and hydrated, it can be easily dispersed in a colloidal form in a solvent or liquid monomer and / or oligomer. Therefore, it is preferable.
[0122]
Further, by subjecting the surface of the inorganic ultrafine particles to a hydrophobic treatment, the dispersibility in a solvent or a liquid monomer and / or oligomer can be improved, and it becomes easy to disperse in a colloidal form. There are many hydroxyl groups on the surface of the inorganic ultrafine particles, and the affinity between the fluorine-containing component and the inorganic ultrafine particles is not so good, so when adding a large amount of inorganic ultrafine particles to the coating composition of the present invention, Even if a coating liquid in which the ultrafine particles are sufficiently dispersed is obtained, the inorganic ultrafine particles may be aggregated in the coating film in the process of drying the coating liquid after coating, and the coating film may be whitened. On the other hand, since the compatibility of the inorganic ultrafine particles with the fluorine-containing component having strong water repellency is improved by hydrophobizing the inorganic ultrafine particles, an effect of preventing such whitening can be obtained.
[0123]
The inorganic ultrafine particles can be rendered hydrophobic by coating with a low molecular organic compound. Specifically, the coating can be performed by dissolving a low molecular weight organic compound in an organic solvent, completely dispersing the inorganic ultrafine particles in this solution, and then completely removing the organic solvent by evaporation. Examples of the low molecular organic compound include low molecular organic carboxylic acids such as stearic acid, lauric acid, oleic acid, linoleic acid, and linolenic acid, and low molecular organic amines.
[0124]
The inorganic ultrafine particles can also be hydrophobized by surface treatment with a coupling agent such as a silane coupling agent or a titanate coupling agent. Among the coupling agents, when the surface of the inorganic ultrafine particles is hydrophobized with a silane coupling agent containing fluorine atoms (fluorine-based silane coupling agent), particularly excellent compatibility with fluorine-containing components is obtained. The whitening of the coating can be effectively prevented.
[0125]
Here, specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane and the like can be exemplified.
[0126]
Among these, when treated with a silane coupling agent having a reactive group, the thermosetting polar group of the binder component, the alkoxy group of the silane coupling agent, and the functional group capable of thermosetting easily bond firmly. The strength of the coating film can be improved.
[0127]
Specific examples of titanate coupling agents are those commercially available from Ajinomoto Co., Inc., such as Preneact KR-TTS, KR-46B, KR-55, KR-41B, KR-38S, KR-138S, and KR. -238S, 338X, KR-44, KR-9SA, KR-ET, etc., and tetramethoxy titanium, tetraethoxy titanium, tetraisopropoxy titanium, tetra n-propoxy titanium, tetra n-butoxy titanium, tetra sec Metal alkoxides such as -butoxy titanium and tetra tert-butoxy titanium can also be used.
[0128]
Examples of the fluorine-based silane coupling agent include trade names TSL8262, TSL8257, TSL8233, and TSL8231 that are fluoroalkylsilane coupling agents manufactured by GE Toshiba Silicone Co., Ltd.
[0129]
Hydrophobized inorganic ultrafine particles can also be obtained as commercial products. Examples of such commercially available products include SiO.₂There are products whose surface is made hydrophobic by adsorbing organic low molecular weight compounds on the surface of fine particles, and they are supplied by Nissan Chemical Co., Ltd. under the trade name organosilica sol.
[0130]
In the coating composition of the present invention, the inorganic ultrafine particles are contained in a proportion of 0.1 to 70% by weight based on the total amount of the solid content including the binder component containing the fluorine-containing component (a), the inorganic ultrafine particles and other components. Preferably, the lower limit is 0.3% by weight or more, and / or the upper limit is 50% by weight or less, particularly 30% by weight or less. Here, solid content of a coating composition is all components other than a solvent, and a liquid monomer and oligomer are also contained in solid content. If the blending ratio of the inorganic ultrafine particles in the coating composition is too small, the hardness and strength of the coating film will not be sufficiently improved. On the other hand, if the blending ratio of the inorganic ultrafine particles is too large, the fluorine-containing component is diluted and refracted. The rate cannot be lowered sufficiently, the binder component in the coating composition is relatively reduced, the coating film becomes brittle, and the film strength is lowered. By containing the inorganic ultrafine particles in the coating composition according to the present invention in a proportion of 0.1 to 70% by weight based on the solid content, there is no or almost no adverse effect on the refractive index lowering effect of the fluorine-containing component, The hardness and strength of the coating film can be improved, and a coating film having a very low refractive index and excellent in hardness and strength can be obtained.
[0131]
When the thermosetting polar group in the binder system (A) is a hydroxyl group, and the surface of the inorganic ultrafine particles (B) is partially formed into a metal hydroxide to produce a hydroxyl group, Since the hydroxyl groups of the inorganic ultrafine particles (B) can be dehydrated and polycondensed by heating to form a covalent bond, the hardness and strength of the coating film are improved. Even when the thermosetting polar group of the binder component is not a hydroxyl group, a covalent bond may be formed with the hydroxyl group on the surface of the inorganic ultrafine particles (B).
[0132]
In addition, by adding a polymerizable functional group to the surface of the inorganic ultrafine particles (B), the covalent bond between the binder component and the inorganic ultrafine particles (B) is increased, and the hardness and strength of the coating film are intentionally improved. Can be made.
[0133]
The polymerizable functional group on the surface of the inorganic ultrafine particle (B) is not particularly limited as long as it can be polymerized with the ionizing radiation curable group and / or the thermosetting polar group of the binder component to form a covalent bond. An appropriate reaction type can be used in accordance with the ionizing radiation curable group and / or thermosetting polar group of the binder component combined with the ultrafine particles (B). Generally, any ionizing radiation curable group and / or thermosetting polar group similar to those of the binder component to be combined may be used.
[0134]
For example, the fluorine-containing component (a) having an ethylenically unsaturated bond and the inorganic ultrafine particles (B) also having an ethylenically unsaturated bond can be combined, and a radical photopolymerization initiator can be added as necessary. Or the fluorine-containing component (a) which has an epoxy group, and the inorganic ultrafine particle (B) which has an amino group and a hydroxyl group can be combined, and the hardening | curing agent of an epoxy reaction can be added as needed. In view of the method of introducing functional groups into the inorganic ultrafine particles (B) and the ease of handling of the curing reaction, the polymerizable functional groups on the surface of the inorganic ultrafine particles (B) may be ionized, such as ethylenically unsaturated bonds. It is preferred to use a radiation curable group.
[0135]
Methods for imparting a polymerizable functional group, preferably an ionizing radiation curable group such as an ethylenically unsaturated bond, to the surface of the inorganic ultrafine particles are roughly classified into the following three.
[0136]
(1) A method of adsorbing a monomer, oligomer or polymer containing a polymerizable functional group on the surface of inorganic ultrafine particles.
[0137]
(2) A method in which inorganic ultrafine particles are hydrophobized with a coupling agent having a polymerizable functional group, and at the same time, a reactive functional group is introduced on the surface.
[0138]
(3) A method of grafting a polymer having a reactive functional group onto the surface of inorganic ultrafine particles.
[0139]
In the above method (1), when adding a component containing a polymerizable functional group to a dispersion solution of inorganic ultrafine particles, for example, if the surface of the inorganic ultrafine particles is hydrophilic, those having polar groups (hydrogen bonding) Use of static electricity, use of hydrophilic interaction), if hydrophobic, use a hydrophobic environment in a hydrophilic environment (use of hydrophobic interaction), or if inorganic ultrafine particles are acidic When the basic one (utilization of acid-base interaction) is selected, the amount adsorbed on the surface of the inorganic ultrafine particles can be increased.
[0140]
In the above method (2), the coupling agent exemplified above can be easily introduced by polycondensation reaction with polar groups on the surface of inorganic ultrafine particles in the presence of an acid or base catalyst if necessary. . In this case, usable coupling agents include monomers, oligomers, and polymers in which an alkoxy group is introduced into the terminal or side chain, in addition to those previously listed in the hydrophobic treatment.
[0141]
The grafting reaction of the polymer onto the surface of the inorganic ultrafine particles (3) is roughly classified into the following three.
[0142]
(3a) Method of capturing polymer growth terminal with inorganic ultrafine particles
Since the hydroxyl group (-OH) present on the surface of the inorganic ultrafine particles has an action of capturing active species such as radicals, for example, a polyfunctional monomer or oligomer polymerization reaction is performed in the presence of the inorganic ultrafine particles, or By adding inorganic ultrafine particles to a polyfunctional monomer or oligomer polymerization system, a monomer, oligomer or polymer having a polymerizable functional group can be bonded to the surface of the fine particles. This is effective when the polymerization reaction is carried out by kneading fine particles in a monomer such as bulk polymerization, but the bonding efficiency is poor.
[0143]
(3b) Method for initiating polymerization reaction from the surface of inorganic ultrafine particles
In this method, a polymerization initiating active species such as a radical polymerization initiator is formed in advance on the surface of inorganic ultrafine particles, and a polymer is grown from the surface of the fine particles using a polyfunctional monomer or oligomer. High molecular weight polymerization-reactive polymer chains are easily obtained, but chain transfer and the like are difficult to control.
[0144]
(3c) A method for bonding a polymer having a reactive group to a hydroxyl group on the surface of inorganic ultrafine particles
Using a polymer having a reactive group having two or more functional groups, the reactive group at the end of the polymer and the hydroxyl group on the surface of the inorganic ultrafine particle are directly bonded, or the reactive group at the polymer end or the hydroxyl group on the surface of the inorganic ultrafine particle This is a method of bonding after any other reactive group is bonded to either or both. Many kinds of polymers can be used, and the coupling efficiency is good with a relatively simple operation.
[0145]
The method of bonding the polymer to the surface of the inorganic ultrafine particle utilizes a dehydration polycondensation reaction between the polymer having a hydroxyl group and a reactive group on the surface of the particle, so that the inorganic ultrafine particle is dispersed in the polymer and its solution at 80 ° C. or higher. Heat for at least 3 hours.
[0146]
The inorganic ultrafine particles (B) having a polymerizable functional group can also be obtained as a commercial product. Such commercially available products include, for example, surface-treated SiO supplied by Clariant Corp. of France under the trade name Highlink OG series.₂Examples of the fine particles include products in which a reactive organic group containing a reactive group such as an ethylenically unsaturated bond or a hydroxyl group or an amino group is bonded. More specifically, products having an ethylenically unsaturated bond include SiO₂There are those in which a hydroxyl group-containing (meth) acrylate such as 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate is ether-bonded to a silanol group on the surface of fine particles. As a product having a hydroxyl group, SiO₂There are those in which silanol groups on the surface of fine particles are ether-bonded with polyhydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, polyethylene glycols, glycerol, trimethylolpropane, or alkoxysilanes. Examples of products having amino groups include SiO₂There are those in which a hydroxyl group-containing amine such as ethanolamine is ether-bonded to silanol groups on the surface of fine particles.
[0147]
In this way, a monomer, oligomer or polymer structure portion having a polymerizable functional group can be introduced on the surface of the inorganic ultrafine particles. In order for the inorganic ultrafine particles (B) to exhibit sufficient curing reactivity, the portion (polymerizable functional group) having a polymerizable functional group introduced on the surface thereof per 100 parts by weight of the inorganic ultrafine particles (B). When the group is directly bonded to the particle surface, the polymerizable functional group itself is preferably present in a proportion of 1 part by weight or more. The amount of the polymerizable functional group bonded to the inorganic ultrafine particles (B) can be measured by elemental analysis.
[0148]
Moreover, it is preferable that the introduction part of the polymerizable functional group present on the surface of the inorganic ultrafine particles (B) has a number average molecular weight in the range of 300 to 20,000.
[0149]
In the case where the inorganic ultrafine particles (B) have two or more ionizing radiation curable groups and / or one or more thermosetting polar groups in one particle, it is preferable because they exhibit sufficient curability by the crosslinking reaction. .
[0150]
When the inorganic ultrafine particles (B) have a polymerizable functional group, the blending ratio of the inorganic ultrafine particles is not particularly limited as long as the fluorine-containing component (b) is substantially blended in the coating composition. In addition, it can be adjusted in a wide range of 0.1 to 99.5% by weight with respect to the total solid content including a binder system containing a fluorine-containing component, inorganic ultrafine particles and other components. Here, solid content of a coating composition is all components other than a solvent, and a liquid monomer and oligomer are also contained in solid content.
[0151]
When the inorganic ultrafine particles (B) have a polymerizable functional group, not only the binder component but also the inorganic ultrafine particles form a covalent bond when the coating composition of the present invention is cured. Even if it mix | blends, a coating film becomes difficult to become brittle and can form into a film.
[0152]
The inorganic ultrafine particles (B) in the coating composition can sufficiently obtain the effect of tightening the coating film even with a small amount that does not affect the refractive index lowering effect of the fluorine-containing component at all or slightly, but the tightening effect is insufficient. Can be blended in relatively large amounts as needed. In addition, when the proportion of inorganic ultrafine particles increases, the fluorine-containing component in the coating composition is diluted and the refractive index lowering effect due to the fluorine-containing component is attenuated. Instead, microvoids are formed in the coating film. Since the refractive index of the coating film is lowered by the action of the microvoids and approaches the refractive index of air, a low refractive index can be obtained by cooperation of the fluorine-containing component and the microvoids.
[0153]
When the blending ratio of the inorganic ultrafine particles in the coating composition is 50% by weight or less based on the total solid content, microvoids are not usually formed in the coating film, and the refractive index of the coating film is mainly controlled by the action of fluorine-containing components. Can be lowered. When the blending ratio of the inorganic ultrafine particles in the coating composition exceeds 50% by weight with respect to the total solid content, microvoids are formed in the coating film depending on the composition of the coating composition, and the fluorine-containing component In addition, the refractive index of the coating film can be lowered by the action of both microvoids. When the blending ratio of the inorganic ultrafine particles in the coating composition is 75% by weight or more based on the total solid content, the action of the fluorine-containing component remains, but the action of reducing the refractive index of the microvoids becomes relatively strong.
[0154]
Thus, when the blending ratio of the inorganic ultrafine particles in the coating composition is increased, the refractive index lowering effect of the coating film by the fluorine-containing component is attenuated, but the fluorine-containing component contributes to the reduction of the refractive index of the coating film, The inorganic ultrafine particles still prevent the decrease in the hardness and strength of the coating film due to the fluorine-containing component.
[0155]
The coating composition according to the present invention contains the fluorine-containing component (a) and the inorganic ultrafine particles (B) as essential components, but if necessary, other than the fluorine-containing component (a) as described above. In addition to the binder component, a solvent, a polymerization initiator, a curing agent, a crosslinking agent, a UV blocker, a UV absorber, a surface conditioner (leveling agent), or other components for preparing the coating liquid You may mix.
[0156]
A polymerization initiator is not necessarily required in the present invention. However, the ionizing radiation curable groups of the fluorine-containing component (a), the inorganic ultrafine particles (B), and other optional binder components may not easily cause a direct polymerization reaction upon irradiation with ionizing radiation. In such a case, it is preferable to use an appropriate initiator in accordance with the reaction mode of the binder component and the inorganic ultrafine particles.
[0157]
For example, when the fluorine-containing component (a) has an ethylenically unsaturated bond which is an ionizing radiation curable group, a photo radical polymerization initiator is used. Examples of photo radical polymerization initiators include acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoro An amine compound or the like is used. More specifically, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, benzyldimethylketone, 1- (4-dodecyl) Phenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane Examples thereof include -1-one and benzophenone. Among these, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one are polymerized by irradiation with ionizing radiation even in a small amount. Since it initiates and accelerates the reaction, it is preferably used in the present invention. These can be used either alone or in combination. These also exist in commercial products. For example, 1-hydroxy-cyclohexyl-phenyl-ketone can be obtained from Ciba Specialty Chemicals Co., Ltd. under the trade name of Irgacure 184.
[0158]
When using a radical photopolymerization initiator, the radical photopolymerization initiator is usually blended in a proportion of 3 to 15 parts by weight with respect to a total of 100 parts by weight of the binder component mainly composed of a fluorine-containing component.
[0159]
A hardening | curing agent is mix | blended in order to accelerate | stimulate the thermosetting reaction of the thermosetting polar group of the fluorine-containing component (b) and the other binder component which is an arbitrary component. When the thermosetting polar group is a hydroxyl group, a compound having a basic group such as methylol melamine or a compound having a hydrolyzable group that generates a hydroxyl group by hydrolysis of a metal alkoxide or the like is usually used as a curing agent. It is done.
[0160]
As the basic group, an amine, nitrile, amide, or isocyanate group is preferably used. As the hydrolyzable group, an alkoxy group is preferably used. In the latter case, the basic group is particularly represented by the following formula (4). Aluminum compounds and derivatives thereof are particularly preferred because they have good compatibility with hydroxyl groups.
[0161]
AlR_Three    ... (4)
(In the formula, R may be the same or different, and is halogen, alkyl having 10 or less carbon atoms, preferably 4 or less, alkyl, alkoxy, allyloxy or hydroxy, and these groups are all or partly chelated. (It may be replaced by a ligand.)
The compound represented by the above formula (4) can be selected from aluminum compounds and / or oligomers derived therefrom and / or complexes and aluminum salts of inorganic or organic acids. Specific examples include aluminum-sec-butoxide, aluminum-iso-propoxide, and acetylacetone, ethyl acetoacetate, alkanolamines, glycols, and complexes with derivatives thereof.
[0162]
In addition, when the thermosetting polar group of the fluorine-containing component (a) or other binder component is an epoxy group, a polyvalent carboxylic acid anhydride or a polyhydric acid is usually used as a curing agent in the coating composition. A monovalent carboxylic acid is used.
[0163]
Specific examples of polyhydric carboxylic acid anhydrides include phthalic anhydride, itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarballylic anhydride, maleic anhydride, hexahydrophthalic anhydride, dimethyltetrahydro anhydride Aliphatic or alicyclic dicarboxylic anhydrides such as phthalic acid, hymic anhydride, and nadic anhydride; fats such as 1,2,3,4-butanetetracarboxylic dianhydride and cyclopentanetetracarboxylic dianhydride Aromatic polycarboxylic dianhydrides; aromatic polycarboxylic anhydrides such as pyromellitic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic anhydride; ester groups such as ethylene glycol bistrimellitic acid and glycerin tristrimellitic acid Containing acid anhydrides, particularly preferably aromatic poly It may be mentioned carboxylic acid anhydrides. Moreover, the epoxy resin hardening | curing agent which consists of a commercially available carboxylic acid anhydride can also be used suitably.
[0164]
Specific examples of the polyvalent carboxylic acid used in the present invention include aliphatic polyvalent carboxylic acids such as succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid, and itaconic acid; hexahydrophthalic acid, Aliphatic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, cyclopentanetetracarboxylic acid, and phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid, Aromatic polyvalent carboxylic acids such as 1,4,5,8-naphthalenetetracarboxylic acid and benzophenonetetracarboxylic acid can be mentioned, and aromatic polyvalent carboxylic acids can be mentioned preferably.
[0165]
When using a hardening | curing agent, a hardening | curing agent is normally mix | blended in the ratio of 0.05-30.0 weight part with respect to a total of 100 weight part of binder components which have a fluorine-containing component as a main component.
[0166]
The crosslinking agent is a component for promoting the crosslinking reaction between the binder component molecules containing the fluorine-containing component (a), between the binder component and the inorganic ultrafine particles (B), and between the inorganic ultrafine particles (B). . For example, when the thermosetting polar group of the fluorine-containing component (a) is a hydroxyl group, the above-described aluminum chelate is preferably used.
[0167]
When a relatively large amount of liquid fluorine-containing monomer and / or oligomer is used as the fluorine-containing component, the fluorine-containing monomer and / or oligomer can also function as a liquid medium for preparing a coating solution. In some cases, the solid component of the coating composition can be dissolved, dispersed, or diluted to prepare a coating solution without using the coating composition. Accordingly, in the present invention, a solvent is not always necessary, but in many cases, a solvent is used to dissolve and disperse solid components, adjust the concentration, and prepare a coating solution having excellent coating suitability.
[0168]
The solvent used for dissolving and dispersing the solid component of the coating composition of the present invention is not particularly limited, and various organic solvents such as alcohols such as isopropyl alcohol, methanol and ethanol; methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. Ketones; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons; aromatic hydrocarbons such as toluene and xylene; or a mixture thereof can be used.
[0169]
In the present invention, it is preferable to use a ketone-based organic solvent. When the coating composition according to the present invention is prepared using a ketone solvent, it can be easily and uniformly applied to the surface of the substrate, and the evaporation rate of the solvent is moderate after coating and hardly causes uneven drying. Therefore, a large-area coating film having a uniform thickness can be easily obtained.
[0170]
In order to impart a function as an antiglare layer to the hard coat layer that is the support layer of the antireflection film, the surface of the hard coat layer is formed with fine irregularities, and then, a medium refractive index layer or a high refractive index layer is interposed therebetween. In some cases, the low refractive index layer is formed by applying the coating composition according to the present invention without or intervening. When the coating composition according to the present invention is prepared using a ketone solvent, it can be applied evenly on the surface of such fine irregularities, and uneven coating can be prevented.
[0171]
As a ketone solvent, it contains a single solvent composed of one kind of ketone, a mixed solvent composed of two or more kinds of ketones, and other solvents together with one or more kinds of ketones, and has lost its properties as a ketone solvent. Those that are not can be used. Preferably, a ketone solvent in which 70% by weight or more, particularly 80% by weight or more of the solvent is occupied by one or two or more ketones is used.
[0172]
The amount of the solvent is appropriately adjusted so that each component can be uniformly dissolved and dispersed, does not cause aggregation during storage after preparation, and does not become too dilute during coating. Prepare a high-concentration coating composition by reducing the amount of solvent used within the range where this condition is satisfied, store it in a state that does not take up the volume, take out the necessary amount at the time of use, and make the concentration suitable for coating work It is preferred to dilute. In the present invention, when the total amount of the solid content and the solvent is 100 parts by weight, the solvent is 50 to 95.5 parts by weight, more preferably, the total solids are 0.5 to 50 parts by weight. By using the solvent in a proportion of 70 to 90 parts by weight with respect to 10 to 30 parts by weight, a coating composition having particularly excellent dispersion stability and suitable for long-term storage can be obtained.
[0173]
In order to prepare the coating composition according to the present invention using each of the above components, it may be dispersed according to a general method for preparing a coating solution. For example, each essential component and each desired component are mixed in an arbitrary order, a medium such as beads is added to the obtained mixture, and a dispersion composition is appropriately dispersed with a paint shaker or a bead mill to obtain a coating composition. .
[0174]
The coating composition thus obtained has at least
(A) It consists of one or two or more binder components including a fluorine-containing component (a) having one or both of a functional group curable by ionizing radiation and a thermosetting polar group in the molecule. A binder system containing both a curing functional group and a thermosetting polar group; and
(B) It can be dispersed in a colloidal form in a liquid medium for preparing a coating solution and contains submicron-order inorganic ultrafine particles.
[0175]
This coating composition does not need to contain inorganic ultrafine particles in a colloidal form when stored at a high concentration, but can be applied by increasing the amount of solvent or liquid fluorine-containing monomer and / or oligomer. When adjusted to a final concentration, it is uniformly dispersed in a colloidal form in the coating solution.
[0176]
By adjusting the coating composition according to the present invention to a final concentration capable of being applied, the binder system (A) containing the fluorine-containing component (a) is contained, and the inorganic ultrafine particles (B) are dispersed in a colloidal form. A liquid coating composition is obtained.
[0177]
In the liquid coating composition, when a solvent is used as the liquid medium, the binder system (A) containing the fluorine-containing component (a) is dissolved or dispersed in the solvent, and the submicron order inorganic is used. It takes a form in which ultrafine particles (B) are dispersed in a colloidal form.
[0178]
In addition, when a liquid fluorine-containing monomer and / or oligomer is used as a binder component and no solvent is used, a submicron-order inorganic supermolecule is contained in a liquid medium comprising the fluorine-containing monomer and / or oligomer as the binder component. It takes a form in which the fine particles (B) are dispersed in a colloidal form.
[0179]
In order to impart sufficient adhesion to the coating composition on the surface of the object to be coated, the amount of the fluorine-containing component (a) having a polar group and the other binder component having a polar group is adjusted, The amount of the thermosetting polar group present in the coating composition is preferably 5 to 80 mol% when the total amount of the ionizing radiation curable group and the thermosetting polar group is 100 mol%. The greater the amount of thermosetting polar groups present in the coating composition, the better the adhesion, but if the amount is too high, the amount of ionizing radiation curable groups contained in the coating composition will be relative. Therefore, the improvement of the hardness and strength of the coating film cannot be expected, or high-speed curing by ionizing radiation curing is impossible and productivity is lowered. Moreover, when there is too much quantity of a thermosetting polar group, there exists a possibility of causing gelatinization as a result of forming many hydrogen bonds with a binder component and inorganic ultrafine particles in the coating liquid of a coating composition.
[0180]
This coating composition is, for example, various methods such as spin coating method, dip method, spray method, slide coating method, bar coating method, roll coater method, meniscus coater method, flexographic printing method, screen printing method, and bead coater method. It can apply | coat on support bodies, such as a base material.
[0181]
The support on which the coating composition of the present invention is applied is not particularly limited. Preferred substrates include, for example, a glass plate; triacetate cellulose (TAC), polyethylene terephthalate (PET), diacetyl cellulose, acetate butyrate cellulose, polyethersulfone, acrylic resin; polyurethane resin; polyester; polycarbonate; Examples thereof include films formed of various resins such as polyether; trimethylpentene; polyether ketone; (meth) acrylonitrile. The thickness of a base material is about 25 micrometers-about 1000 micrometers normally, Preferably it is 50 micrometers-190 micrometers.
[0182]
By coating the coating liquid of the coating composition directly on the surface of an object to be coated such as a base material or through another layer such as a hard coat layer or a light-transmitting anti-glare layer and drying, A coating film having excellent adhesion to the surface of the object to be coated can be obtained by the action of the polar group having thermosetting properties.
[0183]
Further, in this application, the coating composition according to the present invention is excellent in coating suitability and can be easily applied thinly, widely and uniformly on the surface of the object to be coated. Can be formed. In particular, when a ketone solvent is used, the evaporation rate is moderate and unevenness of drying of the coating film hardly occurs, so that it is particularly easy to form a uniform large area thin film.
[0184]
The obtained coating film is dried by using a heating means such as an oven as necessary, and when irradiated with ionizing radiation, it is cured by the action of an ionizing radiation curable group, and has a very low refractive index and can be used practically. A coating film having the hardness and strength to be obtained and excellent in transparency can be obtained. When the inorganic ultrafine particle (B) has an ionizing radiation curable group, the fluorine-containing component (A) and the inorganic ultrafine particle (B) form a covalent bond when the coating film is irradiated with ionizing radiation. It becomes even stronger.
[0185]
In the present invention, it is not essential to thermally cure the coating film of the coating composition, but the thermosetting polar group can be crosslinked directly or via a curing agent or the like by heating the coating film to a predetermined temperature or higher. Therefore, the hardness and strength can be further improved by thermosetting the coating film. When the inorganic ultrafine particles (B) have a thermosetting polar group in the same manner as the fluorine-containing component, the fluorine-containing component (A) and the inorganic ultrafine particles (B) are covalently bonded during the thermosetting reaction. Becomes even stronger.
[0186]
When at least one of the fluorine-containing component (A) or the inorganic ultrafine particles (B) in the coating composition, preferably both have two or more ionizing radiation curable groups or thermosetting polar groups, By curing the film, a coating film having a crosslinked structure is formed between the fluorine-containing polymers, between the inorganic ultrafine particles, and between the fluorine-containing polymer and the inorganic ultrafine particles.
[0187]
The coating film thus obtained is obtained by uniformly mixing submicron-order inorganic ultrafine particles in a fluorine-containing cured binder, but preferably contains a fluorine-containing component or a fluorine-free component added at the same time. It has a structure in which components and inorganic ultrafine particles are covalently bonded, and further contains other components as required.
[0188]
In this coating film, since the cured binder is tightened by the cohesive force and hardness of the inorganic ultrafine particles (B), sufficient film hardness and film strength are imparted, so even when the fluorine content of the binder is high It has the hardness and strength that can withstand practical use. The film hardness and the film strength are further improved by covalently bonding the cured binder and the inorganic ultrafine particles. When the binder of the coating film forms a crosslinked structure, and preferably the inorganic ultrafine particles also form a crosslinked structure together with the binder of the coating film, various physical properties such as film hardness, film strength, and durability are particularly excellent. Therefore, it is preferable. Furthermore, since the size of the metal oxide fine particles is on the order of submicrons, the transparency of the coating film is also excellent.
[0189]
The coating film obtained by the present invention contains a large amount of fluorine, has a very low refractive index, has a hardness and strength that can withstand practical use, and is excellent in transparency. It can be used as a thin film, and can be suitably used as a low refractive index layer of an antireflection film.
[0190]
According to the present invention, the refractive index of the coating film is 1.45 or less, or the number of fluorine atoms contained in the coating film is equal to or more than the number of carbon atoms contained in the coating film. Nevertheless, a coating film having sufficient hardness and strength can be obtained. In addition, the number of atoms of each of fluorine and carbon in the coating film can be measured by elemental analysis.
[0191]
According to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed directly or via another layer on the substrate, the refractive index is adjusted to 1.45 or less, and JIS It can be suppressed that the haze value specified in -K7361-1 does not change from the haze value of only the base material, or the difference from the haze value of the base material alone is within 0.1%.
[0192]
Further, according to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed directly on the substrate or via another layer, the refractive index is adjusted to 1.45 or less, and By using steel wool # 0000 and rubbing the film surface 20 times, the load value at which a change in haze is recognized can be made 1 kg or more, very low refractive index, high transparency, and practical durability. A coating film having the obtained hardness and strength is obtained.
[0193]
Further, according to the present invention, when a coating film having a film thickness of 0.05 to 0.3 μm is formed directly on the substrate or through another layer, the refractive index is 1.45 or less, and steel The change in haze before and after rubbing the film surface 20 times with a load of 200 g using a # 0000 wool is 5% or less, very low refractive index, high transparency, and practically durable hardness A coating film having strength is obtained.
[0194]
Next, specific examples of the antireflection film to which the coating film according to the present invention is applied will be described. The coating film according to the present invention has light transmittance, and when two or more layers are laminated, a single layer type or multilayer type reflection in which one or more layers having different refractive indexes (light transmission layers) are laminated. It can be used to form one of the antireflection films, and is particularly suitable as a low refractive index layer, and is used to form the outermost layer of the antireflection film. In the present invention, in the multilayer antireflection film, the layer having the highest refractive index is referred to as a high refractive index layer, the layer having the lowest refractive index is referred to as a low refractive index layer, and other intermediate refractions. A layer having a refractive index is referred to as a medium refractive index layer.
[0195]
Even if only one layer of the coating film according to the present invention is provided on the surface to be coated with the antireflection film, for example, the display surface of the image display device, the balance between the refractive index of the coating surface itself and the refractive index of the coating film according to the present invention is balanced. When it is just right, an antireflection effect can be obtained. Therefore, the coating film according to the present invention may function effectively as a single-layer antireflection film.
[0196]
The coating film according to the present invention is a multilayer that covers the display surface of an image display device such as a liquid crystal display device (LCD), a cathode ray tube display device (CRT), a plasma display panel (PDP), or an electroluminescence display (ELD). It is suitably used to form at least one type of antireflective coating, particularly a low refractive index layer.
[0197]
FIG. 1 schematically shows a cross section of an example (101) of a liquid crystal display device in which a display surface is covered with a multilayer antireflection film containing a coating film according to the present invention as a light transmission layer. The liquid crystal display device 101 prepares a color filter 4 in which an RGB pixel portion 2 (2R, 2G, 2B) and a black matrix layer 3 are formed on one surface of a glass substrate 1 on the display surface side, and the pixel of the color filter. The transparent electrode layer 5 is provided on the part 2, the transparent electrode layer 7 is provided on one surface of the glass substrate 6 on the backlight side, and the transparent electrode layers 5 and 7 face each other with the glass substrate on the backlight side and the color filter. The liquid crystal L is sealed in the gap, the alignment film 9 is formed on the outer surface of the glass substrate 6 on the back side, and the glass substrate on the display surface side. The polarizing film 10 is affixed on the outer surface of 1, and the backlight unit 11 is arrange | positioned back.
[0198]
FIG. 2 schematically shows a cross section of the polarizing film 10 attached to the outer surface of the glass substrate 1 on the display surface side. The polarizing film 10 on the display surface side covers both surfaces of a polarizing element 12 made of polyvinyl alcohol (PVA) or the like with protective films 13 and 14 made of triacetyl cellulose (TAC) or the like, and an adhesive layer 15 is coated on the back side thereof. The hard coat layer 16 and the multilayer antireflection film 17 are sequentially formed on the viewing side, and are adhered to the glass substrate 1 on the display surface side through the adhesive layer 15.
[0199]
Here, in order to reduce the glare by diffusing the light emitted from the inside as in a liquid crystal display device, the hard coat layer 16 is formed by forming the surface of the hard coat layer into an uneven shape, or the hard coat layer. It is good also as an anti-glare layer (anti-glare layer) which provided the uneven | corrugated shape on the surface by disperse | distributing an inorganic or organic filler to a layer. The hard coat layer 16 may be a layer having internal diffusibility by dispersing an organic or inorganic filler. The hard coat layer may be composed of two or more layers, and the hard coat layers can be used in appropriate combination.
[0200]
The multilayer antireflection film 17 has a three-layer structure in which a middle refractive index layer 18, a high refractive index layer 19, and a low refractive index layer 20 are sequentially laminated from the backlight side to the viewing side. The multilayer antireflection film 17 may have a two-layer structure in which a high refractive index layer 19 or a medium refractive index layer 18 and a low refractive index layer 20 are sequentially stacked. When the surface of the hard coat layer 16 is formed in an uneven shape, the multilayer antireflection film 17 formed thereon also has an uneven shape as shown in the drawing. Further, the high refractive index layer 19 and the medium refractive index layer 18 have hard coat properties and may also serve as a hard coat layer.
[0201]
The low refractive index layer 20 is a coating film formed by applying the coating composition according to the present invention on the high refractive index layer 19, drying, and photocuring, and has a refractive index of 1.46 or less, preferably It can be set to 1.41 or less, and can be lowered to about 1.20. Further, the medium refractive index layer 18 and the high refractive index layer 19 are made of an inorganic oxide having a high refractive index such as titanium oxide or zirconium oxide formed by a vapor deposition method such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). Or a coating film in which inorganic oxide fine particles having a high refractive index such as titanium oxide are dispersed. The medium refractive index layer 18 has a refractive index of 1.46 to 1.80. A light transmissive layer having a refractive index of 1.65 or more is used for the light transmissive layer in the range and the high refractive index layer 19.
[0202]
Furthermore, when it is necessary to impart antistatic properties or electrostatic properties, a conductive layer may be provided on the base film, or conductive particles may be included in the hard coat layer. Furthermore, the same characteristics can be obtained by using a conductive material for the inorganic oxide fine particles having a high refractive index dispersed in the medium refractive index layer or the high refractive index layer. Furthermore, you may combine 2 or more types of the said any layer which has electroconductivity.
[0203]
Due to the action of the antireflection film, the reflectance of light emitted from the external light source is reduced, so that the reflection of scenery and fluorescent light is reduced and the visibility of the display is improved. Moreover, the reflected light of external light is reduced by the light scattering effect by the unevenness | corrugation of the hard-coat layer 16, and the visibility of a display improves further that external light is reflected on the display surface, or is a dazzling state. .
[0204]
In the case of the liquid crystal display device 101, the intermediate refractive index layer 18 having a refractive index adjusted in the range of 1.46 to 1.80 and a refractive index of 1.65 are provided on the laminate including the polarizing element 12 and the protective films 13 and 14. The high refractive index layer 19 adjusted as described above can be formed, and the coating composition according to the present invention can be further applied to provide the low refractive index layer 20. Then, the polarizing film 10 including the antireflection film 17 can be stuck on the glass substrate 1 on the viewing side through the adhesive layer 15.
[0205]
On the other hand, since an alignment plate is not attached to the display surface of the CRT, it is necessary to directly provide an antireflection film. However, applying the coating composition according to the present invention to the display surface of the CRT is a complicated operation. In such a case, an antireflective film containing the coating film according to the present invention is prepared, and the antireflective film is formed by sticking it to the display surface. Therefore, the coating according to the present invention is formed on the display surface. There is no need to apply the composition.
[0206]
One or more light-transmitting layers having a light-transmitting property and a refractive index adjusted are laminated on one or both sides of the base film having light-transmitting properties directly or via another layer, and two or more layers are laminated. In such a case, an antireflection film can be obtained by forming a combination of two or more types of light transmission layers having different refractive indexes and forming at least one of the light transmission layers with the coating film according to the present invention. It is done. The base film and the light transmission layer need to have a light transmittance that can be used as a material for the antireflection film, and are preferably as transparent as possible.
[0207]
FIG. 3 schematically shows a cross section of an example (102) of the antireflection film including the coating film according to the present invention. The antireflection film 102 is formed by forming a high refractive index layer 22 on one surface side of a base film 21 having optical transparency, and further applying a coating composition according to the present invention on the high refractive index layer. A refractive index layer 23 is provided. In this example, there are only two light transmissive layers having different refractive indexes, a high refractive index layer and a low refractive index layer, but three or more light transmissive layers may be provided. In that case, not only the low refractive index layer but also the middle refractive index layer can be formed by applying the coating composition according to the present invention.
[0208]
【Example】
(Example A)
Example A1: Preparation of coating composition
A coating composition was prepared by combining a fluorine-containing polymer having a thermosetting polar group with a fluorine-free polyfunctional acrylate having both an ionizing radiation curable group and a thermosetting polar group.
[0209]
Trade name OPSTAR JN7217 (manufactured by JSR Corporation; solid content: 3% by weight; refractive index: 1.40; JS-1 solution) 10.0 parts by weight of pentaerythritol triacrylate, a hydroxyl group-containing thermosetting fluorine-containing polymer After dissolving 0.1 parts by weight (Nippon Kayaku Co., Ltd.), colloidal silica (trade name MIBK-ST; manufactured by Nissan Chemical Co., Ltd .; solid content 30% by weight; primary particle size 10 nm; methyl isobutyl ketone solution) ) Add 0.67 parts by weight and mix, and further, 0.02 part by weight of trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) as a photopolymerization initiator, and trade name ALCH as a curing agent for thermal polymerization. 0.02 part by weight of TR (manufactured by Kawaken Fine Chemicals Co., Ltd.) was dissolved to obtain a coating composition. The weight ratio of binder component to colloidal silica was 2: 1.
[0210]
(Example A2: Preparation of coating composition)
A coating composition was prepared by combining a fluorine-containing polymer having an ionizing radiation-curable group with a fluorine-free polyfunctional acrylate having both an ionizing radiation-curable group and a thermosetting polar group.
[0211]
Trade name OPSTAR JM5010 (manufactured by JSR Corporation; solid content 10% by weight; refractive index 1.41; methyl ethyl ketone solution) 10.0 parts by weight of pentaerythritol triacrylate (Nipponization) After dissolving 0.2 parts by weight of Yakuhin Co., Ltd., colloidal silica (trade name MIBK-ST; manufactured by Nissan Chemical Co., Ltd .; solid content 30% by weight; primary particle size 10 nm; methyl isobutyl ketone solution) 2% Further, 0.06 parts by weight of trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was dissolved as a photopolymerization initiator to obtain a coating composition. The weight ratio of binder component to colloidal silica was 2: 1.
[0212]
(Example A3: Preparation of coating composition)
A coating composition was prepared by combining a fluorine-containing polymer having both an ionizing radiation curable group and a thermosetting polar group with a fluorine-free polyfunctional acrylate having both an ionizing radiation curable group and a thermosetting polar group.
[0213]
(A3-1) Synthesis of fluoropolymer
CH₂= CFCOOCH₂(CF₂)_FiveCH₂50 parts by weight of a 10% by weight trichlorotrifluoroethane solution of OH was placed in a glass vessel equipped with a condenser, and 0.2 parts by weight of azobisoisobutyronitrile as an initiator was dissolved in the glass container at 80 ° C. under a nitrogen atmosphere. The polymerization reaction was carried out with stirring for 24 hours. After 24 hours, low-boiling substances were distilled off under reduced pressure to obtain 4.5 g of a colorless and transparent polymer.
[0214]
By adding 0.8 parts by weight of 2-methacryloyloxyethyl isocyanate to 30 parts by weight of a solution (solid content: 10% by weight) obtained by dissolving the obtained polymer in tetrahydrofuran, the mixture is reacted at room temperature for 3 hours. A methacryloyl group was introduced into a part of the hydroxyl group of the polymer.
[0215]
After 3 hours, unreacted substances were removed by washing the reaction solution with hexane to obtain a fluorine-containing polymer having both an ionizing radiation curable group and a thermosetting polar group. The number average molecular weight of this polymer in terms of polystyrene by GCP method was about 30,000.
[0216]
(A3-2) Preparation of coating composition
After dissolving 0.2 parts by weight of pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd.) in 10 parts by weight of a 10% by weight methyl isobutyl ketone solution of the obtained fluorine-containing polymer, colloidal silica (trade name MIBK- ST: manufactured by Nissan Chemical Co., Ltd .; solid content 30% by weight; primary particle size 10 nm; methyl isobutyl ketone solution) 2 parts by weight were added and mixed, and further trade name Irgacure 184 (Ciba Specialty Chemicals) as a photopolymerization initiator. 0.06 part by weight was dissolved to obtain a coating composition. The weight ratio of binder component to colloidal silica was 2: 1.
[0217]
(Comparative Example A1: Preparation of coating composition)
A coating composition was obtained by the same composition and procedure as in Example A1, except that no colloidal silica was added.
[0218]
(Comparative Example A2: Preparation of coating composition)
A coating composition was obtained by the same composition and procedure as Example A2, except that no colloidal silica was added.
[0219]
(Comparative Example A3: Preparation of coating composition)
In Example A1, Example 1 was used except that a dispersion of 0.2 part by weight of non-colloidal silica ultrafine particles (trade name Aerosil R971, manufactured by Nippon Aerosil Co., Ltd.) was used instead of colloidal silica. Similarly, a coating composition was obtained. Although a coating film was formed using the obtained coating composition, a transparent coating film was not obtained due to the aggregation of the pigment, and thus the refractive index, reflectance, and other measurements described later could not be performed.
[0220]
(Example A4: Production of single-layer antireflection film)
(A4-1) Formation of transparent hard coat layer
On a triacetyl cellulose substrate, a hard coat coating solution (A4-1) having the following composition was applied with a bar coater, and after drying the solvent, UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.) The H bulb was used as a light source and cured at a dose of 300 mJ to form a transparent hard coat layer having a thickness of 4 μm, thereby obtaining a hard coat substrate A4-1.
<Coating liquid for hard coat (A4-1)>
Pentaerythritol tetraacrylate: 20.0 parts by weight
Photopolymerization initiator (trade name Irgacure 184; manufactured by Ciba Specialty Chemicals): 1.0 part by weight
・ Methyl isobutyl ketone: 80 parts by weight
(A4-2) Formation of antiglare imparting hard coat layer
On a triacetyl cellulose substrate, a hard coat coating solution (A4-2) having the following composition was applied with a bar coater, and after drying the solvent, UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.) Using an H bulb as a light source, it was cured at an irradiation amount of 300 mJ to form a transparent hard coat layer having a thickness of 4 μm, and an antiglare imparting hard coat substrate A4-2 was obtained.
<Coating liquid for hard coat (A4-2)>
Pentaerythritol tetraacrylate: 30.0 parts by weight
・ Cellulose acetate propionate: 0.4 parts by weight
Polystyrene bead paste (trade name SX-130, manufactured by Soken Chemical Co., Ltd.): 10.0 parts by weight
Photopolymerization initiator (trade name Irgacure 184; manufactured by Ciba Specialty Chemicals): 1.0 part by weight
・ Methyl isobutyl ketone: 72.0 parts by weight
(A4-3) Formation of low refractive index layer
The coating compositions of Examples A1, A2, A3 and Comparative Examples A1, A2, A3 were applied by a bar coater on the hard coat layers of the hard coat substrates A4-1 and A4-2 prepared in the above step, and the solvent After drying, the H bulb of a UV irradiation device (Fusion UV Systems Japan Co., Ltd.) is used as a light source and cured at a dose of 300 mJ, and then heated at 80 ° C. for 1 hour to form a low refractive index layer. Thus, antireflection films A4-3a and A4-3b on which an antireflection film was formed were obtained. The film thickness of the low refractive index layer was set so that the minimum reflectance would be near 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation).
[0221]
(Example A5: Production of single-layer antireflection film)
In the same manner as in Example A4, the coating compositions of Examples A1 to A3 were applied on the hard coat layers of the hard coat substrates A4-1 and A4-2, dried, and then irradiated with UV. Cured. Thereafter, a low refractive index layer was formed in the same manner as in Example A4 except that heat curing was not performed, and antireflection films A5-3a and A5-3b on which an antireflection film was formed were obtained.
[0222]
(Evaluation methods)
Each evaluation shown below was performed. The evaluation results are shown in Tables 1 and 2.
[0223]
(1) Refractive index of coating film
The coating compositions of Examples A1, A2, and A3 and Comparative Examples A1, A2, and A3 were applied onto a silicon wafer with a spin coater, the solvent was dried, and then H of a UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.). After curing at a dose of 500 mJ using a bulb as a light source, the film was heated at 80 ° C. for 1 hour to obtain a coating film having a thickness of 0.1 μm. The refractive index of this coating film was measured at a wavelength of 633 nm of helium ion laser light using a spectroscopic ellipsometer (UVISEL; manufactured by Joban Evon).
[0224]
(2) Ratio of fluorine atoms to carbon atoms in the coating (F / C ratio)
Fluorine atoms (F) and carbon atoms (C) in the coating film obtained in (1) above under the following measurement conditions by elemental analysis using an X-ray photoelectron spectrometer ESCALAB 220i-XL manufactured by VG Scientific, England The ratio of was measured.
<Device settings>
・ X-ray source: Al Kα (monochrome ratio)
-X-ray output: 200 W (10 kV, 20 mA)
・ Lens used: Large Area XL
・ Neutralization neutralization: electron neutralization gun, + 4V, neutralization auxiliary mask used (Al conductive tape)
-Photoelectron escape angle: 90 ° (sample normal)
・ Vacuum degree in the measurement chamber: about 3.0 × 10^-7Pa
・ Sample surface cleaning: Ar⁺  Ion etching
<Measurement conditions>
The narrow scan spectrum method was used.
a) C 1s orbit
・ Measurement energy range: 275-295 eV (total energy range)
・ Measurement points: 201 points
・ Step size: 0.10 eV
・ Number of scans: 7 times
・ Pass energy: 20eV
b) F 1s orbit
・ Measurement energy range: 675-695 eV (range of total energy)
・ Measurement points: 201 points
・ Step size: 0.10 eV
・ Number of scans: 5 times
・ Pass energy: 20eV
<Determination of F / C ratio>
The F / C ratio was determined by the intensity ratio of F and C included in the measurement range.
[0225]
(3) Reflectance
The reflectances of the antireflection films A4-3a and A4-3b were measured with a spectrophotometer (manufactured by Shimadzu Corporation).
[0226]
(4) Haze
The haze of the antireflection films A4-3a and A4-3b was measured with a turbidimeter (NDH2000; manufactured by Nippon Denshoku Industries Co., Ltd.).
[0227]
(5) Film hardness
When the surface of the antireflection films A4-3a and A4-3b and further the antireflection films A5-3a and A5-3b are rubbed 20 times with a load of 200-1 kg using # 0000 of steel wool, the haze changes. The load value was detected.
[0228]
[Table 1]

[0229]
[Table 2]

[0230]
(Example B)
Example B1: Preparation of coating composition
A coating composition was prepared by combining a fluorine-containing polymer having an ionizing radiation-curable group, a fluorine-free polyfunctional acrylate having both an ionizing radiation-curable group and a thermosetting polar group, and colloidal silica having a polymerizable group.
[0231]
Trade name OPSTAR JM5010 (manufactured by JSR Corporation; solid content 10% by weight; refractive index 1.41; methyl isobutyl ketone solution) 10.0 parts by weight of pentaerythritol triacrylate (ionizing radiation curable fluorine-containing polymer) After dissolving 0.2 parts by weight of Nippon Kayaku Co., Ltd., colloidal silica having a polymerizable group (trade name Highlink OG108; manufactured by Clariant Japan Co., Ltd .; silica: monomer component = 30: 70 (weight ratio) Monomer type: tripropylene glycol diacrylate) 6.0 parts by weight and mixed, and further, 0.02 parts by weight of trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and Product name ALCH-TR (made by Kawaken Fine Chemicals Co., Ltd.) 0.02 parts by weight as a curing agent for thermal polymerization Dissolved to obtain a coating composition.
[0232]
The trade name Highlink OG108, which is a colloidal silica having a polymerizable group, is a product in which colloidal silica is dispersed in a monomer and a part of the monomer is grafted onto the colloidal silica. The amount of monomer grafted is 10% by weight or more of colloidal silica. The ratio of the binder component to silica was expressed as the ratio of the total amount of the fluorine-containing component and Highlink OG108 to the silica amount of Highlink OG108, and was 3: 1 (binder component: silica).
[0233]
(Example B2)
(B2-1) Preparation of reactive ultrafine particles
Colloidal silica (trade name MIBK-ST; manufactured by Nissan Chemical Co., Ltd .; solid content 30% by weight; primary particle size 10 nm; methyl isobutyl ketone solution) is added to 10 parts by weight of γ-acryloxypropyltrimethoxysilane (KBM5103; Shin-Etsu Chemical). Industrial Co., Ltd.) 0.1 parts by weight and 0.01 parts by weight of acetic acid were added and heated and stirred at 80 ° C. for 12 hours to covalently bond a part of the silane coupling agent onto colloidal silica. It was.
[0234]
(B2-2) Preparation of coating composition
Fluorine-containing component (1.18 parts by weight of the obtained reactive colloidal silica (the solid content remaining after heating up to 300 ° C. by thermogravimetric analysis) was the same as that used in Example 1 ( The product composition Opster JM5010) 10.0 parts by weight and pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd.) 0.2 parts by weight were dispersed in a solution to obtain a coating composition. The weight ratio of binder component to silica was 3: 1.
[0235]
(Comparative Example B1)
The colloidal silica was not added to the fluorine-based binder component of Example B1, and it was used as it was as a coating solution.
[0236]
(Comparative Example B2)
(Ratio B2-1) Preparation of non-colloidal reactive ultrafine particles
10 parts by weight of non-colloidal silica ultrafine particles (trade name Aerosil R971, manufactured by Nippon Aerosil Co., Ltd.), 0.1 parts by weight of γ-acryloxypropyltrimethoxysilane (KBM5103; manufactured by Shin-Etsu Chemical Co., Ltd.), A part of the silane coupling agent was covalently bonded onto the non-colloidal silica ultrafine particles by adding 0.01 parts by weight of acetic acid and stirring with heating at 80 ° C. for 12 hours.
[0237]
(Ratio B2-2) Preparation of coating composition
3 parts by weight of the powder of non-colloidal reactive silica ultrafine particles obtained at the above ratio B2-1 was dispersed in 70 parts by weight of methyl isobutyl ketone. 0.2 parts by weight of pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd.) was dissolved in 10.0 parts by weight of the fluorine-containing component (trade name Opstar JM5010; manufactured by JSR Corporation) used in Example B1. Thereafter, 0.4 part by weight of the non-colloidal reactive silica ultrafine particle dispersion was added to obtain a coating composition. However, since a transparent coating film could not be obtained due to the aggregation of the pigment, the refractive index, reflectance and other measurements described later could not be performed.
[0238]
(Example B3)
(B3-1) Preparation of reactive ultrafine particles
By adding 0.1 part by weight of pentaerythritol triacrylate to 10 parts by weight of the same colloidal silica (trade name MIBK-ST) used in Example B2, and heating and refluxing at 120 ° C. for 1 hour, the above monomer A part of was fixed on colloidal silica.
[0239]
(B3-2) Preparation of coating composition
After dissolving 0.2 parts by weight of pentaerythritol triacrylate in 10.0 parts by weight of the same fluorine-containing component (trade name Opster JM5010) as used in Example B1, the above-mentioned reactive colloidal silica 1.29 parts by weight Was added to obtain a coating composition. The weight ratio of binder component to silica was 3: 1.
[0240]
(Example B4: Production of single-layer antireflection film)
(B4-1) Formation of transparent hard coat layer
On a triacetyl cellulose substrate, a hard coat coating solution (B4-1) having the following composition was applied with a bar coater, and after drying the solvent, UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.) The H bulb was used as a light source and cured at an irradiation amount of 300 mJ to form a transparent hard coat layer having a thickness of 4 μm, thereby obtaining a hard coat base material B4-1.
<Coating liquid for hard coat (B4-1)>
Pentaerythritol tetraacrylate: 20.0 parts by weight
Photopolymerization initiator (trade name Irgacure 184; manufactured by Ciba Specialty Chemicals): 1.0 part by weight
・ Methyl isobutyl ketone: 80 parts by weight
(B4-2) Formation of antiglare imparting hard coat layer
On the triacetyl cellulose substrate, a hard coat coating solution (B4-2) having the following composition was applied with a bar coater, and after drying the solvent, UV irradiation apparatus (manufactured by Fusion UV Systems Japan Co., Ltd.) Using an H bulb as a light source, it was cured at a dose of 300 mJ to form a transparent hard coat layer having a film thickness of 4 μm, and an antiglare imparting hard coat substrate B4-2 was obtained.
<Coating liquid for hard coat (B4-2)>
Pentaerythritol tetraacrylate: 30.0 parts by weight
・ Cellulose acetate propionate: 0.4 parts by weight
Polystyrene bead paste (trade name SX-130, manufactured by Soken Chemical Co., Ltd.): 10.0 parts by weight
Photopolymerization initiator (trade name Irgacure 184; manufactured by Ciba Specialty Chemicals): 1.0 part by weight
・ Methyl isobutyl ketone: 72.0 parts by weight
(B4-3) Formation of low refractive index layer
The coating compositions of Examples B1 to B3, Example A2, and Comparative Examples B1 and B2 were applied on the hard coat layers of the hard coat base materials B4-1 and B4-2 prepared in the above step with a bar coater, and the solvent After drying, the H bulb of a UV irradiation device (Fusion UV Systems Japan Co., Ltd.) is used as a light source and cured at a dose of 300 mJ, and then heated at 80 ° C. for 1 hour to form a low refractive index layer. Antireflection films B4-3a and B4-3b on which an antireflection film was formed were obtained. The film thickness of the low refractive index layer was set so that the minimum reflectance would be near 550 nm when the reflectance was measured with a spectrophotometer (manufactured by Shimadzu Corporation).
[0241]
(Example B5: Production of single-layer antireflection film)
In the same manner as in Example B4, the coating compositions of Examples B1 to B3 were applied on the hard coat layers of the hard coat substrates B4-1 and B4-2, dried, and then irradiated with UV. Cured. Thereafter, a low refractive index layer was formed in the same manner as in Example A4 except that heat curing was not performed, and antireflection films B5-3a and B5-3b on which an antireflection film was formed were obtained.
[0242]
(Evaluation methods)
Each evaluation shown below was performed. The evaluation results are shown in Tables 3 and 4. In addition, in order to compare the effect of the reactive ultrafine particles used in Examples B1 to B3 with the nonreactive ultrafine particles, the coating composition of Example A2 (containing nonreactive colloidal silica) was also evaluated. Was done.
[0243]
(1) Refractive index of coating film
The coating compositions of Examples B1 to B3, Example A2, and Comparative Examples B1 and B2 were applied on a silicon wafer with a spin coater, and the solvent was dried. After curing at an irradiation amount of 500 mJ using an H bulb as a light source, the coating was heated at 80 ° C. for 1 hour to obtain a coating film having a thickness of 0.1 μm. The refractive index of this coating film was measured at a wavelength of 633 nm of helium ion laser light using a spectroscopic ellipsometer (UVISEL; manufactured by Joban Evon).
[0244]
(2) Reflectance
The reflectances of the antireflection films B4-3a and B4-3b were measured with a spectrophotometer (manufactured by Shimadzu Corporation).
[0245]
(3) Haze
The haze of the antireflection films B4-3a and B4-3b was measured with a turbidimeter (NDH2000; manufactured by Nippon Denshoku Industries Co., Ltd.).
[0246]
(4) Film hardness
The surface of the antireflection films B4-3a and B4-3b and further the antireflection films B5-3a and B5-3b are rubbed 20 times with a load of 50 to 1 kg using # 0000 of steel wool, and the change in haze is 5%. The load value when exceeding was detected.
[0247]
[Table 3]

[0248]
[Table 4]

[0249]
【The invention's effect】
As described above, the coating composition according to the present invention mainly comprises the fluorine-containing component (a) having at least one of an ionizing radiation curable group and a thermosetting functional group, and as a whole, an ionizing radiation curable group and It can be prepared in the form of a coating solution in which a binder system containing both thermosetting polar groups is dissolved and dispersed, and inorganic fine particles having a size of submicron order are dispersed in a colloidal state. .
[0250]
Since the fluorine-containing binder is a material having a low refractive index, a coating film having a low refractive index can be formed. However, since a coating film made of a fluorine-containing binder contains fluorine atoms having a small atomic force, hardness and strength are likely to be insufficient. In contrast, when a coating film is formed using the coating composition of the present invention, the coating film can be cured by irradiation with ionizing radiation, and is dispersed in a colloidal state in the cured fluorine-containing binder. Since the coating film is tightened by the cohesive strength and hardness of the inorganic ultrafine particles, even if the fluorine content of the binder component is extremely increased to lower the refractive index, avoid a significant decrease in the hardness and strength of the coating film. be able to.
[0251]
In addition, the inorganic ultrafine particles that can be dispersed in a colloidal state in the coating composition of the present invention have a sufficient effect of tightening the coating film with a small amount that has no or little influence on the refractive index lowering action and film forming property of the fluorine-containing component. Therefore, it is not necessary to add an amount that increases the refractive index and makes the film brittle. Inorganic ultrafine particles are of sub-micron size and are excellent in transparency.
[0252]
Furthermore, since the binder system of the coating composition of the present invention contains a thermosetting polar group, the coating film formed using the coating composition is covered by the action of the thermosetting polar group as a polar group. Excellent adhesion to the coated surface. Moreover, when this coating film is heat-cured, the crosslinking density can be increased by two curing reactions of ionizing radiation curing and thermosetting, and the hardness and strength of the coating film can be further improved.
[0253]
Therefore, by using the coating composition according to the present invention, a coating film having a high fluorine content, a very low refractive index, hardness and strength that can withstand practical use, and excellent adhesion and transparency. can get.
[0254]
Moreover, according to this invention, since said coating film can be created with the apply | coating method using the said coating composition, it is excellent in the mass-productivity of a coating film.
[0255]
The coating film according to the present invention is prepared using the coating composition according to the present invention, and has a structure in which inorganic ultrafine particles are dispersed in a colloidal state in a fluorine-containing binder cured by ionizing radiation. ing. As is apparent from the above, this coating film has a very low refractive index, has a hardness and strength that can withstand practical use, is excellent in adhesion and transparency, and is excellent in mass productivity. This coating film is suitably used as an optical thin film for which a low refractive index is required, particularly as a low refractive index layer of an antireflection film.
[0256]
And the antireflection film containing the coating film which concerns on this invention is applied suitably for display surfaces, such as a liquid crystal display device and CRT.
[Brief description of the drawings]
1 is an example of a liquid crystal display device in which a display surface is coated with a multilayer antireflection film containing a coating film according to the present invention, and is a diagram schematically showing a cross section thereof.
FIG. 2 is an example of an alignment plate provided with a multilayer antireflection film including a coating film according to the present invention, and is a diagram schematically showing a cross section thereof.
FIG. 3 is an example of an antireflection film including a coating film according to the present invention, and is a diagram schematically showing a cross section thereof.
[Explanation of symbols]
101 ... Liquid crystal display device
102: Antireflection film
1 ... Glass substrate on display side
2. Pixel part
3 ... Black matrix layer
4. Color filter
5, 7 ... Transparent electrode layer
6 ... Back side glass substrate
8 ... Sealing material
9 ... Alignment film
10 ... Polarizing film
11 ... Backlight unit
12 ... Polarizing element
13, 14 ... Protective film
15 ... Adhesive layer
16 ... Hard coat layer
17 ... Multilayer antireflection film
18 ... Medium refractive index layer
19 ... High refractive index layer
20 ... Low refractive index layer
21 ... Base film
22 ... High refractive index layer
23 ... Low refractive index layer

Claims (7)

When laminating two or more layers directly or through at least one other layer of the triacetyl cellulose base material, it is necessary to laminate one or more light transmissive layers having different refractive indexes. 1 type or 2 types in which at least one of the light transmission layers contains (A) a fluorine-containing component (a) having one or both of a functional group curable with ionizing radiation and a thermosetting polar group in the molecule. A binder system comprising the above binder components and containing both a functional group that is cured by ionizing radiation and a polar group that is thermally cured, and (B) a functional group that is cured by ionizing radiation per 100 parts by weight of the particle portion on the surface. Inorganic ultra-fine particles having a primary particle diameter of 1 to 500 nm having a group and / or an introduction part having a thermosetting polar group in a ratio of 1 part by weight or more and having two or more of the functional group or the polar group A coating obtained by curing a composition containing particles, wherein the fluorine-containing component (a), the inorganic ultrafine particles, and the inorganic ultrafine particles are functional groups that are cured by the ionizing radiation. And / or an antireflection film for a liquid crystal display device, which is covalently bonded by polymerization between polar groups that are thermally cured. The antireflection film for a liquid crystal display device according to claim 1, wherein the binder system includes a fluorine-containing component (a ') having both a functional group that is cured by ionizing radiation and a polar group that is thermally cured. . The antireflection film for a liquid crystal display device according to claim 1 or 2, wherein the refractive index of the coating film is 1.45 or less . When the thickness of the coating film is 0.05 to 0.3 μm, the refractive index of the coating film is 1.45 or less, and the haze value defined in JIS-K7361-1 of the coating film is The antireflection film for a liquid crystal display device according to any one of claims 1 to 3, wherein a difference between a haze value of only the material and a haze value of only the base material is 0.1% or less . When the thickness of the coating film is 0.05 to 0.3 μm, the refractive index of the coating film is 1.45 or less, and the coating film surface is rubbed 20 times using # 0000 of steel wool. The antireflection film for a liquid crystal display device according to any one of claims 1 to 4 , wherein a load value at which a change in haze is recognized is 1 kg or more . When the thickness of the coating film is 0.05 to 0.3 μm, the coating film has a refractive index of 1.45 or less, and the surface of the coating film is 20 with a 200 g load using # 0000 of steel wool. The antireflection film for a liquid crystal display device according to any one of claims 1 to 4 , wherein a change in haze before and after rubbing is 5% or less . The liquid crystal display device coated with a display surface by a reflection preventing film for a liquid crystal display device according to any one of claims 1 to 6.

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