JP4191992B2 - Antireflection film, polarizing plate, and image display device - Google Patents

Description

【００４２】
一般式（２）においてＲ¹は水素原子、メチル基、メトキシ基、アルコキシカルボニル基、シアノ基、フッ素原子又は塩素原子を表す。アルコキシカルボニル基としては、メトキシカルボニル基、エトキシカルボニル基などが挙げられる。水素原子、メチル基、メトキシ基、メトキシカルボニル基、シアノ基、フッ素原子又は塩素原子が好ましく、水素原子、メチル基、メトキシカルボニル基、フッ素原子又は塩素原子が更に好ましく、水素原子又はメチル基が特に好ましい。
【００４３】
Ｙは単結合、又はエステル基、アミド基、エーテル基もしくはウレア基を表す。単結合、又はエステル基もしくはアミド基が好ましく、単結合又はエステル基が更に好ましく、エステル基が特に好ましい。
【００４４】
Ｌは２価の連結鎖を表す。具体的には、置換もしくは無置換のアルキレン基、置換もしくは無置換のアリーレン基、内部に連結基（例えば、エーテル、エステル、アミドなど）を有する置換もしくは無置換のアルキレン基、内部に連結基を有する置換もしくは無置換のアリーレン基が挙げられ、置換もしくは無置換の炭素数２〜１０のアルキレン基、置換もしくは無置換の炭素数６〜２０のアリーレン基、内部に連結基を有する炭素数３〜１０のアルキレン基が好ましく、無置換のアルキレン基、無置換のアリーレン基、内部にエーテルあるいはエステル連結基を有するアルキレン基が更に好ましく、無置換のアルキレン基、内部にエーテルあるいはエステル連結基を有するアルキレン基が特に好ましい。置換基は、ハロゲン原子、水酸基、メルカプト基、カルボキシル基、エポキシ基、アルキル基、アリール基等が挙げられ、これら置換基は更に置換されていても良い。
【００４５】
ｎは０または１を表す。Ｘが複数存在するとき、複数のＸはそれぞれ同じであっても異なっていても良い。ｎとして好ましくは０である。
Ｒ¹⁰は一般式（１）と同義であり、置換もしくは無置換のアルキル基、無置換のアリール基が好ましく、無置換のアルキル基、無置換のアリール基が更に好ましい。
Ｘは一般式（１）と同義であり、ハロゲン原子、水酸基、または無置換のアルコキシ基が好ましく、塩素原子、水酸基、または無置換の炭素数１〜６のアルコキシ基が更に好ましく、水酸基、または炭素数１〜３のアルコキシ基が更に好ましく、メトキシ基が特に好ましい。
【００４６】
一般式（１）または一般式（２）の化合物は２種類以上を併用しても良い。以下に一般式（１）または一般式（２）で表される化合物の具体例を示すが、本発明はこれらに限定されるものではない。
【００４７】
【化２】

【００４８】
【化３】

【００４９】
【化４】

【００５０】
【化５】

【００５１】
【化６】

【００５２】
【化７】

【００５３】
【化８】

【００５４】
これらの具体例の中で、（Ｍ−１）、（Ｍ−２）、（Ｍ−２５）等が特に好ましい。
【００５５】
本発明の効果を得るためには、オルガノシランの加水分解物および／またはその部分縮合物におけるオルガノシランの含有量は、３０〜１００質量％が好ましく、５０〜１００質量％がより好ましく、７０〜１００質量％が更に好ましく、９０〜１００質量％が特に好ましい。オルガノシランの含有量が３０質量％より少ないと、固形分が生じたり、液が濁ったり、ポットライフが悪化したり、分子量の制御が困難（分子量の増大）であったり、重合性基の含有量が少ないために重合処理を行った場合の性能（例えば反射防止膜の耐傷性）の向上が得られにくいために好ましくない。
【００５６】
オルガノシランの加水分解物および／またはその部分縮合物の重量平均分子量は、分子量が３００未満の成分を除いた場合に、１０００〜２００００が好ましく、１０００〜１００００がより好ましく、１１００〜５０００が更に好ましく、１２００〜３０００が更に好ましく、１２００〜２０００が更に好ましい。
オルガノシランの加水分解物および／またはその部分縮合物における分子量が３００以上の成分のうち、分子量が２００００より大きい成分は２０質量％以下であることが好ましく、１５質量％以下であることがより好ましく、１０質量％以下であることが更に好ましく、６質量％以下であることが更に好ましく、４質量％以下であることが特に好ましい。
また、オルガノシランの加水分解物および／またはその部分縮合物における分子量３００以上の成分のうち、分子量１０００〜２００００の成分は８０質量％以上であることが好ましい。８０質量％未満であると、そのようなオルガノシランの加水分解物および／またはその部分縮合物を含有する反射防止フィルムは、透明性や密着性が劣る場合がある。
【００５７】
ここで、重量平均分子量及び分子量は、ＴＳＫgel ＧＭＨxL、ＴＳＫgel Ｇ4000ＨxL、ＴＳＫgel Ｇ2000ＨxL（何れも商品名、東ソー(株)製）のカラムを使用したＧＰＣ分析装置により、溶媒ＴＨＦ、示差屈折計検出によるポリスチレン換算で表した分子量であり、含有量は、分子量が３００以上の成分のピーク面積を１００％とした場合の、前記分子量範囲のピークの面積％である。
分散度（重量平均分子／数平均分子量）は３．０〜１．１が好ましく、２．５〜１．１がより好ましく、２．０〜１．１が更に好ましく、１．５〜１．１が特に好ましい。
【００５８】
オルガノシランの加水分解物および／または部分縮合物の²⁹Ｓｉ−ＮＭＲ分析により一般式（１）のＸが−ＯＳｉの形で縮合している状態を確認できる。
この時、Ｓｉの３つの結合が−ＯＳｉの形で縮合している場合（Ｔ３）、Ｓｉの２つの結合が−ＯＳｉの形で縮合している場合（Ｔ２）の比率（Ｔ３／Ｔ２）を縮合度とした場合に、縮合度は０．５〜３．５が好ましく、０．５〜３．０がより好ましく、０．７〜２．５がとくに好ましい。
０．５より小さいと加水分解や縮合が十分でなく、モノマー成分が増えるため硬化が十分でなく、３．５より大きいと加水分解や縮合が進みすぎ、加水分解可能な基が消費されてしまうため、バインダーポリマー、樹脂基板、無機微粒子などの相互作用が低下してしまい、これらを用いても効果が得られにくくなる。
【００５９】
オルガノシランの加水分解および／または縮合反応は、無溶媒でも、溶媒中でも行うことができ、本発明の硬化性組成物を製造することができる。溶媒を用いる場合はオルガノシランの加水分解物および／またはその部分縮合物の濃度を適宜に定めることができる。溶媒としては成分を均一に混合するために有機溶媒を用いることが好ましく、例えばアルコール類、芳香族炭化水素類、エーテル類、ケトン類、エステル類などが好適である。
溶媒はオルガノシランと触媒を溶解させるものが好ましい。また、有機溶媒が塗布液あるいは塗布液の一部として用いられることが工程上好ましく、含フッ素樹脂などのその他の素材と混合した場合に、溶解性あるいは分散性を損なわないものが好ましい。
【００６０】
このうち、アルコール類としては、例えば１価アルコールまたは２価アルコールを挙げることができ、このうち１価アルコールとしては炭素数１〜８の飽和脂肪族アルコールが好ましい。これらのアルコール類の具体例としては、メタノール、エタノール、ｎ−プロピルアルコール、ｉ−プロピルアルコール、ｎ−ブチルアルコール、sec−ブチルアルコール、tert−ブチルアルコール、エチレングリコール、ジエチレングリコール、トリエチレングリコール、エチレングリコールモノブチルエーテル、酢酸エチレングリコールモノエチルエーテルなどを挙げることができる。
【００６１】
また、芳香族炭化水素類の具体例としては、ベンゼン、トルエン、キシレンなどを、エーテル類の具体例としては、テトラヒドロフラン、ジオキサンなどを、ケトン類の具体例としては、アセトン、メチルエチルケトン、メチルイソブチルケトン、ジイソブチルケトンなどを、エステル類の具体例としては、酢酸エチル、酢酸プロピル、酢酸ブチル、炭酸プロピレンなどを挙げることができる。
これらの有機溶媒は、１種単独であるいは２種以上を混合して使用することもできる。該反応における溶媒に対する固形分の濃度は特に限定されるものではないが通常１〜９０質量％の範囲であり、好ましくは２０〜７０質量％の範囲である。
【００６２】
オルガノシランの加水分解および／または縮合反応は、触媒の存在下で行われることが好ましい。触媒としては、塩酸、硫酸、硝酸等の無機酸類；シュウ酸、酢酸、ギ酸、メタンスルホン酸、トルエンスルホン酸等の有機酸類；水酸化ナトリウム、水酸化カリウム、アンモニア等の無機塩基類；トリエチルアミン、ピリジン等の有機塩基類；トリイソプロポキシアルミニウム、テトラブトキシジルコニウム等の金属アルコキシド類等が挙げられるが、ゾル液の製造安定性やゾル液の保存安定性の点から、本発明においては、酸触媒（無機酸類、有機酸類）が好ましい。無機酸では塩酸、硫酸、有機酸では、水中での酸解離定数(ｐＫａ値(25℃))が４．５以下のものが好ましく、塩酸、硫酸、水中での酸解離定数が３．０以下の有機酸がより好ましく、塩酸、硫酸、水中での酸解離定数が２．５以下の有機酸が更に好ましく、水中での酸解離定数が２．５以下の有機酸が更に好ましく、メタンスルホン酸、シュウ酸、フタル酸、マロン酸が更に好ましく、シュウ酸が特に好ましい。
【００６３】
加水分解および／または縮合反応は、通常、オルガノシランの加水分解性基１モルに対して０．３〜２モル、好ましくは０．５〜１モルの水を添加し、上記溶媒の存在下あるいは非存在下に、そして好ましくは触媒の存在下に、２５〜１００℃で、撹拌することにより行われる。
加水分解性基がアルコキシドで触媒が有機酸の場合には、有機酸のカルボキシル基やスルホ基がプロトンを供給するために、水の添加量を減らすことができ、オルガノシランのアルコキシド基１モルに対する水の添加量は、０〜２モル、好ましくは０〜１．５モル、より好ましくは、０〜１モル、特に好ましくは、０〜０．５モルである。アルコールを溶媒に用いた場合には、実質的に水を添加しない場合も好適である。
【００６４】
触媒の使用量は、触媒が無機酸の場合には加水分解性基に対して０．０１〜１０モル％、好ましくは０．１〜５モル％であり、触媒が有機酸の場合には、水の添加量によって最適な使用量が異なるが、水を添加する場合には加水分解性基に対して０．０１〜１０モル％、好ましくは０．１〜５モル％であり、実質的に水を添加しない場合には、加水分解性基に対して１〜５００モル％、好ましくは１０〜２００モル％であり、より好ましくは２０〜２００モル％であり、更に好ましくは５０〜１５０モル％であり、特に好ましくは５０〜１２０モル％である。反応は２５〜１００℃で撹拌することにより行われるがオルガノシランの反応性により適宜調節されることが好ましい。
【００６５】
オルガノシランのゾルの適宜な含有量は、添加する層によっても異なるが、低屈折率層の添加量は含有層（添加層）の全固形分の０．１〜５０質量％が好ましく、０．５〜２０質量％がより好ましく、１〜１０質量％が特に好ましい。低屈折率層以外の光学薄膜層への添加量は、含有層（添加層）の全固形分の０．００１〜５０質量％が好ましく、０．０１〜２０質量％がより好ましく、０．０５〜１０質量％が更に好ましく、１〜５質量％が特に好ましい。
【００６６】
低屈折率層における、含フッ素樹脂に対するオルガノシランのゾルの使用量は、５〜１００質量％が好ましく、５〜４０質量％がより好ましく、８〜３５質量％が更に好ましく、１０〜３０質量％が特に好ましい。使用量が少なすぎると本発明の効果が得にくく、使用量が多すぎると屈折率が増加したり、膜の形状・面状が悪化したりするので好ましくない。
低屈折率層に上記オルガノシランを添加する場合に、該低屈折率層に隣接する層が無機酸化物微粒子を含有すると、層間の密着力が増加し、より好ましい。高屈折率層に上記オルガノシランを添加する場合も同様に、隣接する低屈折率層および／または中屈折率層が無機酸化物微粒子を含有するとより好ましい。
【００６７】
中屈折率層および高屈折率層は、屈折率の高い無機微粒子、熱または電離放射線硬化性のモノマー、開始剤、好ましくは上記オルガノシランゾル、および溶媒を含有する塗布組成物の塗布、溶媒の乾燥、熱および／または電離放射線による硬化によって形成される。無機微粒子としては、Ｔｉ、Ｚｒ、Ｉｎ、Ｚｎ、Ｓｎ、Ｓｂの酸化物から選ばれた少なくとも１種の金属酸化物からなるものが好ましい。このようにして形成された中屈折率層および高屈折率層は、高屈折率を有するポリマー溶液を塗布、乾燥したものと比較して、耐傷性や密着性に優れる。分散液安定性や、硬化後の膜強度等を確保するために、特開平１１−１５３７０３号公報や米国特許第６，２１０，８５８号明細書等に記載されているような、多官能（メタ）アクリレートモノマーとアニオン性基含有（メタ）アクリレート分散剤とが塗布組成物中に含まれることが好ましい。
【００６８】
無機微粒子の平均粒径は、コールターカウンター法で測定したときの平均粒径で１〜１００ｎｍであることが好ましい。１ｎｍ以下では、比表面積が大きすぎるために、分散液中での安定性に乏しく、好ましくない。１００ｎｍ以上では、バインダとの屈折率差に起因する可視光の散乱が発生し、好ましくない。高屈折率層および中屈折率層のヘイズは、３％以下であることが好ましく、１％以下であることがより好ましく、０．５％以下であることが更に好ましい。
【００６９】
低屈折率層には、熱または電離放射線により硬化する含フッ素樹脂が主成分として含まれる。上記オルガノシランゾル、無機フィラーを含有すると、他の層との密着性、自層の強度が向上する為に耐擦傷性が著しく改良され、好ましい。また、低屈折率層と隣接する他の光学薄膜層に上記オルガノシラン化合物、その加水分解物またはその部分縮合物を含有すると、該層間の密着性が向上して好ましく、低屈折率層と隣接する他の光学薄膜層と低屈折率層に共に上記オルガノシランゾルを含有すると、該層間の密着性が向上し、特に好ましい。
該硬化物の動摩擦係数は好ましくは０．０３〜０．１５、純水に対する接触角は好ましくは１００〜１２０度である。動摩擦係数が０．１５より高いと、表面を擦った時に傷つきやすくなり、好ましくない。また、純水に対する接触角が１００度未満では指紋や油汚れ等が付着しやすくなるため、防汚性の観点で好ましくない。
該硬化性の含フッ素樹脂としてはパーフルオロアルキル基含有シラン化合物（例えば（ヘプタデカフルオロ−１，１，２，２−テトラデシル）トリエトキシシラン）等の他、含フッ素モノマーと架橋性基付与のためのモノマーを構成単位とする含フッ素共重合体が挙げられる。
【００７０】
含フッ素モノマー単位の具体例としては、例えばフルオロオレフィン類（例えばフルオロエチレン、ビニリデンフルオライド、テトラフルオロエチレン、ヘキサフルオロエチレン、ヘキサフルオロプロピレン、パーフルオロ−２，２−ジメチル−１，３−ジオキソール等）、（メタ）アクリル酸の部分または完全フッ素化アルキルエステル誘導体類（例えばビスコート６ＦＭ（商品名、大阪有機化学製）やＭ−２０２０（商品名、ダイキン製）等）、完全または部分フッ素化ビニルエーテル類等であり、これらのなかでも低屈折率、モノマーの扱いやすさの観点で特にヘキサフルオロプロピレンが好ましい。
【００７１】
架橋性基付与のためのモノマーとしてはグリシジルメタクリレートのように分子内にあらかじめ架橋性官能基を有する（メタ）アクリレートモノマーの他、カルボキシル基やヒドロキシル基、アミノ基、スルホン酸基等を有する（メタ）アクリレートモノマー（例えば（メタ）アクリル酸、メチロール（メタ）アクリレート、ヒドロキシアルキル（メタ）アクリレート、アリルアクリレート等）が挙げられる。後者は共重合の後、架橋構造を導入できることが特開平１０−２５３８８号公報および特開平１０−１４７７３９号公報により開示されており、特に好ましい。
【００７２】
また上記含フッ素モノマーを構成単位とするポリマーだけでなく、フッ素原子を含有しないモノマーとの共重合体を用いてもよい。併用可能なモノマー単位には特に限定はなく、例えばオレフィン類（エチレン、プロピレン、イソプレン、塩化ビニル、塩化ビニリデン等）、アクリル酸エステル類（アクリル酸メチル、アクリル酸メチル、アクリル酸エチル、アクリル酸２−エチルヘキシル）、メタクリル酸エステル類（メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、エチレングリコールジメタクリレート等）、スチレン誘導体（スチレン、ジビニルベンゼン、ビニルトルエン、α−メチルスチレン等）、ビニルエーテル類（メチルビニルエーテル等）、ビニルエステル類（酢酸ビニル、プロピオン酸ビニル、桂皮酸ビニル等）、アクリルアミド類（Ｎ−ｔｅｒｔブチルアクリルアミド、Ｎ−シクロヘキシルアクリルアミド等）、メタクリルアミド類、アクリロ二トリル誘導体等を挙げることができ、特開平１０−２５３８８号公報および特開平１０−１４７７３９号公報により開示されている。
【００７３】
さらに耐傷性、防汚性を付与する目的で、含フッ素ポリマーにはポリシロキサン構造が導入されていることが好ましい。ポリシロキサン構造の導入方法に制限はないが例えば特開平１１−１８９６２１号、同１１−２２８６３１号、特開２０００−３１３７０９号の各公報に記載のごとくシリコーンマクロアゾ開始剤を用いてポリシロキサンブロック共重合成分を導入する方法、特開平２−２５１５５５号公報、同２−３０８８０６号公報に記載のごとくシリコーンマクロマーを用いてポリシロキサングラフト共重合成分を導入する方法が好ましい。これらのポリシロキサン成分はポリマー中の０．５〜１０質量％であることが好ましく、特に好ましくは１〜５質量％である。
【００７４】
防汚性付与に対しては上記以外にも反応性基含有ポリシロキサン（例えばＫＦ−１００Ｔ、Ｘ−２２−１６９ＡＳ、ＫＦ−１０２、Ｘ−２２−３７０１ＩＥ、Ｘ−２２−１６４Ｂ，Ｘ−２２−５００２、Ｘ−２２−１７３Ｂ、Ｘ−２２−１７４Ｄ、Ｘ−２２−１６７Ｂ、Ｘ−２２−１６１ＡＳ（以上商品名、信越化学工業社製）、ＡＫ−５、ＡＫ−３０，ＡＫ−３２（以上商品名、東亜合成社製）、サイラプレーンＦＭ０２７５、サイラプレーンＦＭ０７２１（以上チッソ社製）等）を添加する手段も好ましい。この際これらのポリシロキサンは低屈折率層全固形分の０.５〜１０質量％の範囲で添加されることが好ましく、特に好ましくは１〜５質量％の場合である。
【００７５】
低屈折率層に用いられる無機フィラーとしては低屈折率のものが好ましく用いられ、好ましい無機フィラーは、シリカ、フッ化マグネシウムであり、特にシリカが好ましい。
該無機フィラーの平均粒径は０．００１〜０．２μｍであることが好ましく、０．００１〜０．０５μｍであることがより好ましい。フィラーの粒径はなるべく均一（単分散）であることが好ましいが、２種類以上の異なる粒径を有する単分散フィラーを併用することも可能であり、特に耐擦傷性を改良する目的では好ましく用いられる。
【００７６】
低屈折率層の形成に用いる含フッ素樹脂の屈折率は、反射防止性の観点からは屈折率が低いほど好ましいが、含フッ素樹脂の屈折率を下げていくと耐傷性が悪化する。そこで、含フッ素樹脂の屈折率と上記無機フィラーの添加量を最適化することにより、耐傷性と低屈折率のバランスの最も良い点を見出すことができる。含フッ素樹脂と無機フィラーの配合比は、９５：５〜５０：５０が好ましく、９０：１０〜６０：４０がより好ましい。
上記無機フィラーの中で特に好ましいシリカのフィラーとしては、市販の有機溶剤に分散されたシリカゾルをそのまま塗布組成物に添加しても、市販の各種シリカ紛体を有機溶剤に分散して使用してもよい。
【００７７】
反射防止フィルムには、さらに、ハードコート層、前方散乱層、帯電防止層、下塗り層や保護層を設けてもよい。
ハードコート層は、透明支持体に耐傷性を付与するために設ける。ハードコート層は、透明支持体とその上の層との接着を強化する機能も有する。ハードコート層は、多官能アクリルモノマー、ウレタンアクリレート、エポキシアクリレート等のオリゴマー、各種重合開始剤を溶媒に溶解した組成物に、必要に応じてシリカ、アルミナ等の無機フィラーを添加して得られた塗布組成物の塗布、溶媒の乾燥、熱および／または電離放射線により硬化することで好ましく形成される。詳細については後述する。
【００７８】
ハードコート層の厚さは、１〜３０μｍであることが好ましく、２〜２０μｍであることがさらに好ましく、３〜１０μｍであることが最も好ましい。
ハードコート層の鉛筆硬度はＨ以上であることが好ましく、２Ｈ以上であることがさらに好ましく、３Ｈ以上であることが最も好ましい。
ハードコート層の屈折率は、１．４５〜１．８の範囲が好ましく、支持体の屈折率との差が０〜０．３の範囲内であるものが好ましい。
【００７９】
ハードコート層は二酸化珪素を主とする無機化合物からなる層、飽和炭化水素またはポリエーテルを主鎖として有するポリマー等の有機化合物からなる層、あるいは無機／有機化合物のハイブリッド化された層として形成できる。飽和炭化水素を主鎖として有するポリマーからなる層であることが特に好ましい。ポリマーは架橋していることが好ましい。飽和炭化水素を主鎖として有するポリマーは、エチレン性不飽和モノマーの重合反応により得ることが好ましい。架橋しているバインダーポリマーを得るためには、二以上のエチレン性不飽和基を有するモノマーを用いることが好ましい。
【００８０】
二以上のエチレン性不飽和基を有するモノマーの例には、多価アルコールと（メタ）アクリル酸とのエステル（例、エチレングリコールジ（メタ）アクリレート、１，４−ジクロヘキサンジアクリレート、ペンタエリスリトールテトラ（メタ）アクリレート）、ペンタエリスリトールトリ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、トリメチロールエタントリ（メタ）アクリレート、ジペンタエリスリトールテトラ（メタ）アクリレート、ジペンタエリスリトールペンタ（メタ）アクリレート、ペンタエリスリトールヘキサ（メタ）アクリレート、１，２，３−シクロヘキサンテトラメタクリレート、ポリウレタンポリアクリレート、ポリエステルポリアクリレート）、ビニルベンゼンおよびその誘導体（例、１，４−ジビニルベンゼン、４−ビニル安息香酸−２−アクリロイルエチルエステル、１，４−ジビニルシクロヘキサノン）、ビニルスルホン（例、ジビニルスルホン）、アクリルアミド（例、メチレンビスアクリルアミド）およびメタクリルアミドが含まれる。
ポリエーテルを主鎖として有するポリマーは、多官能エポシキ化合物の開環重合反応により合成することが好ましい。
これらのエチレン性不飽和基を有するモノマーは、塗布後電離放射線または熱による重合反応により硬化させる必要がある。
【００８１】
二以上のエチレン性不飽和基を有するモノマーの代わりまたはそれに加えて、架橋性基の反応により、架橋構造をバインダーポリマーに導入してもよい。架橋性官能基の例には、イソシアナート基、エポキシ基、アジリジン基、オキサゾリン基、アルデヒド基、カルボニル基、ヒドラジン基、カルボキシル基、メチロール基および活性メチレン基が含まれる。ビニルスルホン酸、酸無水物、シアノアクリレート誘導体、メラミン、エーテル化メチロール、エステルおよびウレタン、テトラメトキシシランのような金属アルコキシドも、架橋構造を導入するためのモノマーとして利用できる。ブロックイソシアナート基のように、分解反応の結果として架橋性を示す官能基を用いてもよい。また、本発明において架橋基とは、上記化合物に限らず上記官能基が分解した結果反応性を示すものであってもよい。
これら架橋基を有する化合物は塗布後熱などによって架橋させる必要がある。
【００８２】
更にハードコート層には、屈折率の調節や膜の硬化強度を高めるために無機の微粒子を添加しても良い。無機の微粒子としては平均粒子サイズが０．００１〜０．５μｍのものが好ましく、０．００１〜０．２μｍのものが特に好ましい。無機微粒子としては二酸化珪素粒子、二酸化チタン粒子、酸化アルミニウム粒子、酸化錫粒子、炭酸カルシウム粒子、硫酸バリウム粒子、タルク、カオリンおよび硫酸カルシウム粒子があげられ、二酸化珪素粒子、二酸化チタン粒子、酸化アルミニウム粒子が特に好ましい。
無機微粒子の添加量は、ハードコート層の全質量の１０〜９０質量％であることが好ましく、２０〜８０質量％であると更に好ましく、３０〜６０質量％が特に好ましい。
【００８３】
前方散乱層は、液晶表示装置に適用した場合の、上下左右方向に視角を傾斜させたときの視野角改良効果を付与するために設ける。上記ハードコート層中に屈折率の異なる微粒子を分散することで、ハードコート機能と兼ねることもできる。
【００８４】
本発明の塗布組成物のウエット塗布による多層反射防止フィルムに表面凹凸によって背景の映り込みをぼかす、防眩性を付与する場合には、一般に用いられているようなマット粒子等を含有する表面凹凸を有する層の上に反射防止層を形成するよりも、エンボス法等によって反射防止層形成後に表面凹凸構造を形成したほうが、膜厚均一性が良化するため、反射防止性能が向上するので好ましい。
【００８５】
反射防止フィルムの各層は、ディップコート法、エアーナイフコート法、カーテンコート法、ローラーコート法、ワイヤーバーコート法、グラビアコート、マイクログラビア法やエクストルージョンコート法（米国特許第２，６８１，２９４号明細書）により、塗布により形成することができる。ウエット塗布量を最小化することで乾燥ムラをなくす観点でマイクログラビア法およびグラビア法が好ましく、幅方向の膜厚均一性の観点で特にグラビア法が好ましい。本発明の反射防止フィルムの複数の光学薄膜のうちの少なくとも２層を、１回の支持体フィルムの送り出し、各々の該光学薄膜の形成、フィルムの巻取り、の工程にて形成するのが、生産コストの観点で好ましく、反射防止層が３層構成の場合には、３層を１回の工程にて形成するのが好ましい。このような製造方法は、塗布機の支持体フィルムの送り出しから巻取りまでの間に、塗布ステーションと乾燥、硬化ゾーンのセットを複数個、好ましくは光学薄膜の数と同じ数以上、縦列して設けることによって達成される。
【００８６】
上記のような複数個の塗布ステーションを設ける代わりに、２層以上の層を同時に塗布してもよい。同時塗布の方法については、米国特許第２，７６１，７９１号、同第２，９４１，８９８号、同第３，５０８，９４７号、同第３，５２６，５２８号の各明細書、および原崎勇次著「コーティング工学」、２５３頁、朝倉書店（１９７３）に記載がある。
【００８７】
本発明の反射防止フィルム２枚を偏光子の表面と裏面に貼り合わせることによって偏光板を形成することができる。この場合、本発明の反射防止フィルムを少なくとも偏光板の片側の表面保護フィルムとして用いることが好ましい。
本発明の反射防止フィルムを偏光子の表面保護フィルムの片側として用いる場合には、透明支持体の反射防止層が形成される面とは反対側の面をアルカリによって鹸化処理することが必要である。アルカリ鹸化処理の具体的手段としては、以下の２つから選択することができる。汎用のトリアセチルセルロースフィルムと同一の工程で処理できる点で（１）が優れているが、反射防止膜面まで鹸化処理されるため、表面がアルカリ加水分解されて膜が劣化する点、鹸化処理液が残ると汚れになる点が問題になり得る。その場合には、特別な工程となるが、（２）が優れる。
（１）透明支持体上に反射防止層を形成後に、アルカリ液中に少なくとも１回浸漬することで、該フィルムの裏面を鹸化処理する。
（２）透明支持体上に反射防止層を形成する前または後に、アルカリ液を該反射防止フィルムの反射防止フィルムを形成する面とは反対側の面に塗布し、加熱、水洗および／または中和することで、該フィルムの裏面だけを鹸化処理する。
【００８８】
偏光子には、ヨウ素系偏光子、二色性染料を用いる染料系偏光子やポリエン系偏光子がある。ヨウ素系偏光子および染料系偏光子は、一般にポリビニルアルコール系フィルム（以下、ＰＶＡと記載する）が好ましく用いられる。ＰＶＡは通常、ポリ酢酸ビニルをケン化したものであるが、変性ＰＶＡも用いることができる。ＰＶＡを染色して偏光膜が得られる。染色を行う例としては、ヨウ素-ヨウ化カリウム水溶液にＰＶＡフィルムを浸漬させる方法、ヨウ素あるいは染料溶液の塗布あるいは噴霧など任意の手段で行うことができる。ＰＶＡを延伸して偏光膜を製造する過程では、ＰＶＡを架橋させる添加物、例えばホウ酸類を用いることが好ましい。偏光板の透過率は、波長５５０ｎｍの光において、３０乃至５０％の範囲にあることが好ましく、３５乃至５０％の範囲にあることがさらに好ましい。偏光度は、波長５５０ｎｍの光において、９０乃至１００％の範囲にあることが好ましく、９５乃至１００％の範囲にあることがさらに好ましく、９９乃至１００％の範囲にあることが最も好ましい。
【００８９】
特開平８−５０２０６号公報や特開２００１−１０００４３号公報等に記載されているように、偏光板は、表面保護フィルムのうちの偏光子に対して反射防止フィルムとは反対側の面に光学異方性層を少なくとも１層含んでなる光学補償層を有する光学補償フィルムを有し、該光学異方性層がディスコティック構造単位を有する化合物からなる複屈折を有する層であり、該ディスコティック構造単位の円盤面が該表面保護フィルム面に対して傾いており、且つ該ディスコティック構造単位の円盤面と該表面保護フィルム面とのなす角度が、光学異方性層の深さ方向において変化していることが好ましい。
【００９０】
本発明の反射防止フィルムは、偏光子の表面保護フィルムの片側として用いた場合、ツイステットネマチック（ＴＮ）、スーパーツイステットネマチック（ＳＴＮ）、バーティカルアライメント（ＶＡ）、インプレインスイッチング（ＩＰＳ）、オプティカリーコンペンセイテットベンドセル（ＯＣＢ）等のモードの透過型、反射型、または半透過型の液晶表示装置に好ましく用いることができる。また、透過型または半透過型の液晶表示装置に用いる場合には、市販の輝度向上フィルム（偏光選択層を有する偏光分離フィルム、例えば住友３Ｍ（株）製のＤ−ＢＥＦ（商品名）など）と併せて用いることにより、さらに視認性の高い表示装置を得ることができる。また、透過型、反射型、および半透過型の液晶表示装置において液晶セルの全面に空気を介してアクリル板等の前面板を配する場合には、液晶セル表面側の偏光板だけでなく、前面板の内側及び／または外側に粘着剤等を介して貼り付けること、界面の反射を低減することができるため好ましい。また、λ／４板と組み合わせることで、反射型または半透過型のＬＣＤや、有機ＥＬディスプレイ用表面保護板として用いることができる。さらに、ＰＥＴ、ＰＥＮ等の透明支持体上に本発明の反射防止層を形成して、ＰＤＡ、携帯電話の表面保護板、タッチパネル、プラズマディスプレイパネル（ＰＤＰ）や陰極管表示装置（ＣＲＴ）のような画像表示装置に適用できる。
【００９１】
【実施例】
本発明を実施例に基づきさらに詳細に説明するが、本発明はこれらに限定されるものではない。
（ハードコート層用塗布液Ａの調製）
ジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）３０６質量部を、１６質量部のメチルエチルケトンと２２０質量部のシクロヘキサノンの混合溶媒に溶解した。得られた溶液に、光重合開始剤（商品名：イルガキュア９０７、チバガイギー社製）７．５質量部を加え、溶解するまで攪拌した後に、４５０質量部のＭＥＫ−ＳＴ（平均粒径１０〜２０ｎｍ、固形分濃度３０質量％のＳｉＯ₂ゾルのメチルエチルケトン分散物、日産化学（株）製、商品名）を添加し、撹拌して混合物を得、孔径０．４μｍのポリプロピレン製フィルター（ＰＰＥ−０３（商品名、富士写真フイルム（株）製））で濾過してハードコート層用塗布液Ａを調製した。
【００９２】
（ハードコート層用塗布液Ｂの調製）
上記ハードコート層用塗布液Ａ（溶剤乾燥し、紫外線硬化後の屈折率：１．５１）１０００質量部に、平均粒径１．３μｍの架橋ポリスチレンからなる前方散乱性付与粒子（商品名：ＳＸ−１３０Ｈ、屈折率：１．６１、綜研化学（株）製）１５０質量部を追添加し、エアディスパーにて１０分間攪拌して混合物を得、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過して、前方散乱性を付与した、ハードコート層用塗布液Ｂを調製した。
【００９３】
（ハードコート層用塗布液Ｃの調製）
ジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）９１質量部、粒径約３０ｎｍの酸化ジルコニウム超微粒子分散物含有ハードコート塗布液（商品名：デソライトＺ−７４０１、ＪＳＲ（株）製）２１８質量部を、５２質量部のメチルエチルケトン／シクロヘキサノン＝５４／４６質量％の混合溶剤に溶解した。得られた溶液に、光重合開始剤（商品名：イルガキュア９０７、チバファインケミカルズ（株）製）１０質量部を加え、撹拌して混合物を得、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過してハードコート層用塗布液Ｃを調製した。
【００９４】
（オルガノシランゾル組成物Ａの調製）
攪拌機、還流冷却器を備えた反応器に、グリシドキシプロピルトリメトキシシラン１６１質量部、シュウ酸１２３質量部、エタノール４１５質量部を加え混合したのち、７０℃で５時間反応させた後室温まで冷却しオルガノシランのゾル組成物Ａを得た。
【００９５】
（オルガノシランゾル組成物Ｂの調製）
オルガノシランゾル組成物Ａの調製において、グリシドキシプロピルトリメトキシシランをメタクリロイルオキシプロピルトリメトキシシランに換えた他は、オルガノシランゾル組成物Ａの調製と同様にしてオルガノシランゾル組成物Ｂを得た。
【００９６】
（二酸化チタン分散物の調製）
二酸化チタン超微粒子（商品名：ＴＴＯ−５５Ｂ、石原テクノ（株）製）３０質量部、ジメチルアミノエチルアクリレート（ＤＭＡＥＡ、興人（株）製）１質量部、リン酸基含有アニオン性分散剤（商品名：ＫＡＹＡＲＡＤ ＰＭ−２１、日本化薬（株）製）６質量部およびシクロヘキサノン６３質量部を、サンドグラインダーによって、コールター法で測定した平均粒径が４２ｎｍになるまで分散し、二酸化チタン分散物を調製した。
【００９７】
（中屈折率層用塗布液Ａの調製）
シクロヘキサノン７５質量部およびメチルエチルケトン１９質量部に、光重合開始剤（商品名：イルガキュア９０７、チバガイギー社製）０．１１質量部および光増感剤（商品名：カヤキュアーＤＥＴＸ、日本化薬（株）製）０．０４質量部を溶解した。さらに、二酸化チタン分散物３．１質量部およびジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）２．１質量部を加え、室温で３０分間撹拌した後、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過して、中屈折率層用塗布液Ａを調製した。
【００９８】
（中屈折率層用塗布液Ｂの調製）
シクロヘキサノン７５０質量部、メチルエチルケトン１９０質量部に、光重合開始剤（商品名：イルガキュア９０７、チバガイギー社製）１．２質量部および光増感剤（商品名：カヤキュアーＤＥＴＸ、日本化薬（株）製）０．４質量部を溶解した。さらに、二酸化チタン分散物１０５質量部およびジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）２１質量部を加え、室温で３０分間撹拌した後、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過して、中屈折率層用塗布液Ｂを調製した。
【００９９】
（高屈折率層用塗布液Ａの調製）
シクロヘキサノン５４質量部およびメチルエチルケトン１８質量部に、光重合開始剤（商品名：イルガキュア９０７、チバガイギー社製）０．１３質量部および光増感剤（商品名：カヤキュアーＤＥＴＸ、日本化薬（株）製）０．０４質量部を溶解した。さらに、二酸化チタン分散物２６．４質量部およびジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）１．６質量部を加え、室温で３０分間撹拌した後、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過して、高屈折率層用塗布液Ａを調製した。
【０１００】
（高屈折率層用塗布液Ｂの調製）
シクロヘキサノン５２質量部およびメチルエチルケトン１８質量部に、光重合開始剤（商品名：イルガキュア９０７、チバガイギー社製）０．１３質量部および光増感剤（商品名：カヤキュアーＤＥＴＸ、日本化薬（株）製）０．０４質量部を溶解した。さらに、二酸化チタン分散物２６．４質量部およびジペンタエリスリトールペンタアクリレートとジペンタエリスリトールヘキサアクリレートの混合物（ＤＰＨＡ、日本化薬（株）製）１．６質量部とオルガノシランゾル組成物Ａ２．３３質量部を加え、室温で３０分間撹拌した後、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）で濾過して、高屈折率層用塗布液Ｂを調製した。
【０１０１】
（低屈折率層用塗布液Ａの調製）
屈折率１．４２であり、熱架橋性含フッ素樹脂の６質量％のメチルエチルケトン溶液（商品名：ＪＮ−７２２８、ＪＳＲ（株）製）を溶媒置換して、メチルイソブチルケトン８５質量％、２−ブタノール１５質量％からなる混合溶媒中に固形分１０質量％を含有するポリマー溶液を得た。このポリマー溶液７０質量部にＭＥＫ−ＳＴ（平均粒径１０〜２０ｎｍ、固形分濃度３０質量％のＳｉＯ₂ゾルのメチルエチルケトン分散物、日産化学（株）製、商品名）１０質量部、オルガノシランゾル組成物Ａ ２．１７質量部、およびメチルイソブチルケトン４２質量部およびシクロヘキサノン２８質量部を添加、攪拌の後、孔径０．４μｍのプロファイルスター０．４μｍ（商品名、日本ポール社（株）製）でろ過して、低屈折率層用塗布液Ａを調製した。
【０１０２】
（低屈折率層用塗布液Ｂの調製）
オルガノシランゾル組成物Ａ ２．１７質量部をオルガノシランゾル組成物Ｂ２．１７質量部に置き換えた以外は低屈折率層用塗布液Ａと同様にして、低屈折率層用塗布液Ｂを調製した。
【０１０３】
（低屈折率層用塗布液Ｃの調製）
オルガノシランゾル組成物Ａ ２．１７質量部を添加しない以外は低屈折率層用塗布液Ａと同様にして、低屈折率層用塗布液Ｃを調製した。
【０１０４】
［実施例１］
（反射防止フィルムの作製）
８０μｍの厚さのトリアセチルセルロースフィルム（ＴＡＣ−ＴＤ８０Ｕ、商品名、富士写真フィルム（株）製、屈折率：１．４７）に、上記のハードコート層用塗布液Ａを、グラビアコーターを用いて塗布し、１００℃で２分間乾燥した。次に紫外線を照射して、塗布層を硬化させ、ハードコート層（屈折率：１．５１、膜厚：６μｍ）を形成した。
続いて、上記の中屈折率層用塗布液Ａをグラビアコーターを用いて塗布し、１００℃で乾燥した後、紫外線を照射して塗布層を硬化させ、中屈折率層（屈折率：１．６３、膜厚：６７ｎｍ）を設けた。
中屈折率層の上に、上記の高屈折率層用塗布液Ａをグラビアコーターを用いて塗布し、１００℃で乾燥した後、紫外線を照射して塗布層を硬化させ、高屈折率層（屈折率：１．９０、膜厚：１０７ｎｍ）を設けた。
さらに高屈折率層の上に、上記の低屈折率層用塗布液をグラビアコーターを用いて塗布し、１２０℃で１分間乾燥した後に、紫外線を照射し、さらに１２０℃で８分間、塗布層を熱硬化させ、低屈折率層Ａ（屈折率：１．４３、膜厚：８６ｎｍ）を設けた。このようにして反射防止フィルムを作製した。
なお、中屈折率層の塗布、乾燥、硬化と、高屈折率層の塗布、乾燥、硬化と、低屈折率層の塗布、乾燥、硬化は、一つの塗布機内に３つの塗布ステーション、乾燥、硬化ゾーンのセットを有する塗布機にて、１回の塗布工程の中で連続的に実施した。
【０１０５】
［比較例１］
物理蒸着法により、実施例１のハードコート上に順次、酸化チタン（屈折率：２．３９）２５ｎｍと酸化ケイ素（屈折率１．４７）２５ｎｍの２層からなる実質上中屈折率層、酸化チタン４６ｎｍからなる高屈折率層、酸化ケイ素９７ｎｍからなる低屈折率層を形成し、反射防止フィルムを作製した。
図２に本発明の実施例１および比較例１の反射防止フィルムの波長３８０ｎｍから７８０ｎｍまでにおける反射率スペクトルを示す。図２及び表３から明らかなように、比較例１に比べて実施例１では、反射スペクトルの長波長側、短波長側の上昇が低減されており、反射光の色味も低減されていることがわかった。
【０１０６】
［実施例２］
実施例１で作製した反射防止フィルムを、２．０規定、５５℃のＮａＯＨ水溶液中に２分間浸漬してフィルムの裏面のトリアセチルセルロース面を鹸化処理し、８０μｍの厚さのトリアセチルセルロースフィルム（ＴＡＣ−ＴＤ８０Ｕ、商品名、富士写真フィルム（株）製）を同条件で鹸化処理したフィルムとでポリビニルアルコールにヨウ素を吸着させ、延伸して作製した偏光子の両面を接着、保護して偏光板を作製した。このようにして作製した偏光板を、反射防止膜側が最表面となるように透過型ＴＮ液晶表示装置搭載のノートパソコンの液晶表示装置（偏光選択層を有する偏光分離フィルムである住友３Ｍ（株）製のＤ−ＢＥＦ（商品名）をバックライトと液晶セルとの間に有する）の視認側の偏光板と貼り代えたところ、背景の映りこみが極めて少なく、表示品位の非常に高い表示装置が得られた。
【０１０７】
［実施例３］
実施例２の鹸化処理を、１．０規定のＫＯＨ水溶液を＃３バーにて反射防止フィルムの裏面に塗布し、膜面温度６０℃にて１０秒間処理した後に水洗、乾燥して行った以外は実施例２と同様にして、液晶表示装置に貼り付けたところ、実施例２と同様の表示品位の高い表示装置が得られた。
【０１０８】
［実施例４］
実施例３の反射防止フィルムを貼り付けた透過型ＴＮ液晶セルの視認側の偏光板の液晶セル側の保護フィルムおよびバックライト側の偏光板の液晶セル側の保護フィルムに、ディスコティック構造単位の円盤面が透明支持体面に対して傾いており、且つ該ディスコティック構造単位の円盤面と透明支持体面とのなす角度が、光学異方層の深さ方向において変化している光学補償層を有する視野角拡大フィルム（ワイドビューフィルムＳＡ−１２Ｂ、商品名、富士写真フィルム（株）製）を用いたところ、明室でのコントラストに優れ、且つ、上下左右の視野角が非常に広く、極めて視認性に優れ、表示品位の高い液晶表示装置が得られた。
【０１０９】
［実施例５〜７および比較例２］
実施例１のハードコート、中屈折率層、高屈折率層、低屈折率層用の塗布液に代わり、下記表１に示した塗布液を用いた以外は実施例１と同様にして、実施例５〜７、比較例２の反射防止フィルムを作製した。
【０１１０】
【表１】

【０１１１】
実施例１、５〜７および比較例２の反射防止フィルムの耐擦傷性を、以下に記述する方法にて評価した。その結果を下記表２に示す。
【０１１２】
［反射防止フィルムの耐擦傷性評価方法］
（１）スチールウール擦り試験
耐擦傷性の指標として、反射防止フィルムを温度２５℃、湿度６０％ＲＨで２時間調湿した後、＃００００のスチールウールを用いて、２００ｇの荷重にて１０往復擦った後に、反射防止フィルムの裏面を黒インクにてベタ塗りし、反射防止膜側を蛍光灯下で目視することで、以下の４段階判定で評価した。
目視にて、擦った傷が全く見えない ：◎
目視にて、擦った傷が殆ど見えない ：○
目視にて、擦った傷が見えるが、目立たない ：△
目視にて、擦った傷が目立つ ：×
【０１１３】
（２）ウエット擦り試験
耐擦傷性のもう一つの指標として、反射防止フィルムを温度２５℃、湿度６０％ＲＨで２時間調湿した後、市販の綿棒の先の部分に純水を充分に含ませ、１ｋｇの荷重にて５０往復擦った後に、反射防止フィルムの裏面を黒インクにてベタ塗りし、反射防止膜側を蛍光灯下で目視することで、以下のとおりの４段階判定で評価した。
目視にて、擦った傷が全く見えない ：◎
目視にて、擦った傷が殆ど見えない ：○
目視にて、擦った傷が見えるが、目立たない ：△
目視にて、擦った傷が目立つ ：×
【０１１４】
【表２】

【０１１５】
表２から明らかなように、比較例２は、オルガノシラン化合物の加水分解物または部分縮合物が添加されていないため、層間の密着力において実施例１、５〜７に劣り、実施例１、５〜７と比較して耐擦傷性に劣ることがわかった。これに対して、実施例１、５〜７の反射防止フィルムは、複数の光学薄膜の少なくとも１層に、層間の密着力、自層の硬度が高いため、耐擦傷性に優れることがわかった。
【０１１６】
［実施例８］
実施例１のハードコート用塗布液Ａの代わりにハードコート層用塗布液Ｂを用いた以外は実施例１と同様にして、前方散乱機能を有する反射防止フィルムを作製し、実施例４と同様にして、最表面側にこの前方散乱性反射防止フィルムを、液晶セル側に視野角拡大フィルムワイドビューフィルム（ＷＶ−１２Ａ、商品名、富士写真フィルム（株）製）を有する偏光板を配置した透過型ＴＮ液晶表示装置を作製した。
このようにして作製した液晶表示装置は、実施例４と比較して、下方向に視角を倒した時の階調反転が起こる限界角が４０度から６０度まで改善され、視認性、表示品位において大変優れたものであった。
【０１１７】
［実施例９］
実施例３の反射防止層を有する偏光板を最表面に配し、アクリル前面板の内側と外側の両面に実施例１で作製した反射防止フィルムを粘着剤を介して貼り合わせて、前面板を最表面に配した半透過型液晶表示装置を具備する携帯電話を作製したところ、前面板のない反射防止処理した液晶表示装置と遜色のない、視認性の高い表示装置が得られた。
【０１１８】
［比較例３〜５］
実施例９で用いたアクリル前面板の内側と外側の両面に実施例１で作製した反射防止フィルムを貼り合せたものを、前面板の内側だけに実施例１の反射防止フィルムを貼り合せたもの、なにも貼り合せなかったもの、及び前面板にも液晶セルにも反射防止のないものに代えた以外は実施例９と同様にして半透過型液晶表示装置を具備する携帯電話を作製したところ、いずれも反射防止フィルムの枚数の減少とともに視認性が悪化し、特に、反射防止なしのものは蛍光灯等の映りこんだところの文字が完全に読めなくなった。
【０１１９】
［実施例１０］
実施例１で作製した反射防止フィルムを有機ＥＬ表示装置の表面のガラス板に粘着剤を介して貼り合わせたところ、ガラス表面での反射が抑えられ、視認性の高い表示装置が得られた。
【０１２０】
［実施例１１］
実施例３で作製した片面反射防止フィルム付き偏光板の反射防止膜を有している側の反対面にλ／４板を張り合わせ、有機ＥＬ表示装置の表面のガラス板に貼り付けたところ、表面反射および、表面ガラスの内部からの反射がカットされ、極めて視認性の高い表示が得られた。
【０１２１】
［実施例１２］
片面下塗り層を有し、厚み１８８μｍのポリエチレンテレフタレートフィルム（商品名：コスモシャインＡ４１００、帝人（株）製、屈折率：１．６５）の下塗り面にハードコート用塗布液Ｃを実施例１と同様にして塗布、溶媒の乾燥、紫外線硬化を行い、ハードコート層（屈折率：１．６１、膜厚：８μｍ）を形成した。
続いて、上記の中屈折率層用塗布液Ｂをグラビアコーターを用いて塗布し、１００℃で乾燥した後、紫外線を照射して塗布層を硬化させ、中屈折率層（屈折率：１．７０、膜厚：７０ｎｍ）を設けた。
中屈折率層の上に、上記の高屈折率層用塗布液をグラビアコーターを用いて塗布し、１００℃で乾燥した後、紫外線を照射して塗布層を硬化させ、高屈折率層（屈折率：１．９０、膜厚：１２０ｎｍ）を設けた。
さらに高屈折率層の上に、上記の低屈折率層用塗布液Ａをグラビアコーターを用いて塗布し、１２０℃で８分間、塗布層を硬化させ、低屈折率層（屈折率：１．４３、膜厚：９０ｎｍ）を設けた。なお、中屈折率層〜低屈折率層までは、実施例１と同様に、一つの塗布機内に３つの塗布ステーション、乾燥、硬化ゾーンのセットを有する塗布機にて、１回の塗布工程の中で連続的に実施した。
このようにして反射防止フィルムを作製した。
作製した反射防止フィルムをフラットＣＲＴ、およびＰＤＰの最表面に貼り付けたところ、低反射、反射光の色味低減、および高い膜硬度を同時に満足した表示装置が得られた。
【０１２２】
（反射防止フィルムの評価）
実施例１及び１２並びに比較例１で得られたフィルムについて、以下の項目の評価を行った。その結果については後記の表３に示す。
（１）鏡面反射率及び色味
分光光度計Ｖ−５５０（商品名、日本分光（株）製）にアダプターＡＲＶ−４７４（商品名）を装着して、３８０〜７８０ｎｍの波長領域において、入射角５°における出射角-５度の鏡面反射率を測定し、４５０〜６５０ｎｍの平均反射率を算出し、反射防止性を評価した。
さらに、測定された反射スペクトルから、ＣＩＥ標準光源Ｄ₆₅の５度入射光に対する正反射光の色味を表わすＣＩＥ１９７６Ｌ^*ａ^*ｂ^*色空間のＬ^*値、ａ^*値、ｂ^*値を算出し、反射光の色味を評価した。
（２）鉛筆硬度評価
耐傷性の指標としてＪＩＳ Ｋ ５４００に記載の鉛筆硬度評価を行った。反射防止フィルムを温度２５℃、湿度６０％ＲＨで２時間調湿した後、ＪＩＳ Ｓ６００６に規定する２Ｈ〜５Ｈの試験用鉛筆を用いて、５００ｇの荷重にて、以下のとおりの判定で評価し、ＯＫとなる最も高い硬度を評価値とした。
ｎ＝５の評価において傷なし〜傷１つ ：ＯＫ
ｎ＝５の評価において傷が３つ以上 ：ＮＧ
（３）接触角測定
表面の耐汚染性の指標として、光学材料を温度２５℃、湿度６０％ＲＨで２時間調湿した後、純水の接触角を測定し、指紋付着性の指標とした。
【０１２３】
（４）動摩擦係数測定
表面滑り性の指標として動摩擦係数にて評価した。動摩擦係数は試料を２５℃、相対湿度６０％で２時間調湿した後、ＨＥＩＤＯＮ−１４（商品名）動摩擦測定機により５ｍｍφステンレス鋼球、荷重１００ｇ、速度６０ｃｍ／ｍｉｎにて測定した値を用いた。
（５）垂直剥離帯電量測定
本文中に記載した通りの方法で垂直剥離帯電量を測定した。
（６）表面抵抗値
円電極法により表面抵抗値を測定した。
【０１２４】
【表３】

【０１２５】
表３から明らかなように、実施例１および実施例１２の反射防止フィルムは、低反射率と色味低減が両立され、非常に好ましい反射特性を有するだけでなく、動摩擦が低いため、耐傷性に優れ、純水の接触角が高いことから、撥水、撥油性に優れるため、防汚性に優れ、さらに、鉛筆硬度が高く、傷がつき難いことがわかった。これに対し、比較例１の反射防止フィルムは、反射光が赤紫色に強く着色しており、表示品位に劣っていた。また、動摩擦が高いため、耐傷性に劣り、純水の接触角が低く、防汚性が悪いものであった。
さらに、ＴＤ方向、ＭＤ方向に１０ｃｍ離れた任意の２つの場所における波長３８０ｎｍから７８０ｎｍまでの領域におけるＣＩＥ標準光源Ｄ₆₅の５度入射光に対する正反射光の色味ムラが、ＣＩＥ１９７６Ｌ^*ａ^*ｂ^*色空間のΔＥ^* _ab値で０〜１．５の範囲に入っているため、場所違いでの反射光の色味の均一性が高い。また、表面抵抗値はいずれも１×１０¹²Ω／□以上であったが垂直剥離帯電が＋１２０ｐＣ（ピコクーロン）／ｃｍ²であり、防塵性に優れていた。
【０１２６】
［実施例１３］
実施例２の偏光子に、以下の方法で作製した偏光子を用いる以外は、実施例２と同様にして、偏光板を作製した。反射防止性能は実施例１と同一であったが、得られた偏光子の吸収軸方向は、長手方向に対し４５゜傾斜しており、偏光板を各サイズに打ち抜く際に発生する打ち抜き屑が減少した。
（偏光子の作製）
ＰＶＡフィルムをヨウ素５．０ｇ／Ｌ、ヨウ化カリウム１０．０ｇ／Ｌの水溶液に２５℃にて９０秒浸漬し、さらにホウ酸１０ｇ／Ｌの水溶液に２５℃にて６０秒浸漬後、米国特許公開第２００２−８８４０Ａ１号明細書のＦｉｇ．２の形態のテンター延伸機に導入し、７．０倍に一旦延伸した後５．３倍まで収縮させ、以降幅を一定に保ち、７０℃で乾燥した後テンターより離脱した。左右のテンタークリップの搬送速度差は、０．０５％未満であり、導入されるフィルムの中心線と次工程に送られるフィルムの中心線のなす角は、０゜であった。ここでＦｉｇ．２中、｜Ｌ１−Ｌ２｜、Ｗとも０．７ｍであった。テンター出口におけるシワ、フィルム変形は観察されなかった。この偏光子の５５０ｎｍにおける透過率は４３．３％、偏光度は９９．９８％であった。
【０１２７】
【発明の効果】
本発明の反射防止フィルムは、十分な反射防止性能と防汚性を有しながら耐傷性が向上している。
【図面の簡単な説明】
【図１】本発明の反射防止フィルムの具体例を示す模式図である。
【図２】本発明の実施例１および比較例１の反射防止フィルムの波長３８０ｎｍから７８０ｎｍまでにおける反射率スペクトルである。
【符号の説明】
１ 透明支持体
２ ハードコート層
３ 中屈折率層
４ 高屈折率層
５ 低屈折率層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antireflection film, a polarizing plate using the same, and an image display device using them.
[0002]
[Prior art]
The antireflection film is provided in various image display devices such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display device (CRT). Anti-reflection films are also provided on glasses and camera lenses.
As an antireflection film, a multilayer film obtained by laminating a transparent thin film of metal oxide has been conventionally used. The reason for using a plurality of transparent thin films is to prevent reflection of light in a wavelength range as wide as possible in the visible range. The transparent thin film of metal oxide is formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, particularly a vacuum vapor deposition method or a sputtering method which is a kind of physical vapor deposition method. A transparent thin film of metal oxide has excellent optical properties as an antireflection film, but a film formation method by vapor deposition or sputtering is low in productivity and is not suitable for mass production.
[0003]
Instead of the vapor deposition method, a method of forming an antireflection film by applying inorganic fine particles has been proposed.
Patent Document 1 discloses an antireflection layer having fine pores and fine inorganic particles. The antireflection layer is formed by coating. The fine pores are formed by performing an activated gas treatment after the application of the layer and releasing the gas from the layer.
Patent Document 2 discloses an antireflection film in which a support, a high refractive index layer, and a low refractive index layer are laminated in this order. This document also discloses an antireflection film in which an intermediate refractive index layer is provided between a support and a high refractive index layer. The low refractive index layer is formed by applying a polymer or inorganic fine particles.
[0004]
Patent Document 3 describes two or more types of ultrafine particles (for example, MgF₂And SiO₂), And the mixing ratio is changed in the film thickness direction. The refractive index is changed by changing the mixing ratio, and the same optical properties as the antireflection film provided with the high refractive index layer and the low refractive index layer described in Patent Document 2 are obtained. The ultrafine particles are composed of SiO generated by the thermal decomposition of ethyl silicate.₂It is adhered by. In the thermal decomposition of ethyl silicate, carbon dioxide and water vapor are also generated by combustion of the ethyl portion. As shown in FIG. 1 of Patent Document 3, carbon dioxide and water vapor are separated from the layer, thereby forming a gap between the ultrafine particles.
Patent Document 4 discloses that the ultrafine particle gap existing in the antireflection film described in Patent Document 3 is filled with a binder.
Patent Document 5 discloses an antireflection film containing inorganic fine powder made of porous silica and a binder.
Patent Document 6 discloses a film having an antireflection film having a three-layer structure by wet coating using a layer in which at least two inorganic fine particles are stacked on a low refractive index layer to contain microvoids. A technique for providing an antireflection film that achieves both low film strength and low reflectance at a low production cost by all wet coating has been disclosed.
[0005]
As described above, a material having a refractive index as low as possible is desired for the low refractive index layer, but an antireflection film is used for the outermost surface of the display, so that high scratch resistance is required. In order to realize high scratch resistance in a thin film having a thickness of around 100 nm, the strength of the coating itself and the adhesion to the lower layer are required.
Patent Documents 7 to 9 describe means for reducing the coefficient of friction on the coating surface and improving the scratch resistance by introducing a polysiloxane structure into the fluorine-containing resin. This means is effective to some extent for improving scratch resistance, but sufficient scratch resistance cannot be obtained only by this method for a film having an essential film strength and interfacial adhesion.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 60-59250
[Patent Document 2]
JP 59-50401 A
[Patent Document 3]
JP-A-2-245702
[Patent Document 4]
Japanese Patent Laid-Open No. 5-13021
[Patent Document 5]
JP 7-48527 A
[Patent Document 6]
Japanese Patent Laid-Open No. 11-6902
[Patent Document 7]
JP-A-11-189621
[Patent Document 8]
Japanese Patent Laid-Open No. 11-228631
[Patent Document 9]
JP 2000-313709 A
[0007]
In addition to the above-mentioned problem of scratch resistance, the antireflection film manufactured by the above-described vapor deposition method or sputtering method has an average reflectance of 0.4% or less in the wavelength region from 450 nm to 650 nm. When the color of the reflected light is strongly colored from magenta to blue-violet, there is a problem that the display quality is deteriorated when the reflected light source is behind. On the other hand, the antireflection film manufactured by wet coating is used in such a way that the reflected light color is close to neutral, but the average reflectivity exceeds 1%, and external light is directly incident on the display surface. Below, the antireflection performance was insufficient. In Example 24 in Patent Document 6 described above, the average reflectance is 0.35% by wet coating, but when the color of the reflected light is calculated from the reflection spectrum, the color of the reflected light is very strong. Even if a real sample was prepared and visually judged, it was strongly colored reddish purple, and there was also a problem that display quality was impaired. Further, since the color of the reflected light is strong, there is a problem that the color is greatly shifted due to slight film thickness unevenness of the antireflection layer, and is detected visually as unevenness.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an antireflection film having improved anti-scratch properties while having sufficient antireflection performance and antifouling properties.
Furthermore, it is to provide such an antireflection film with high productivity.
Furthermore, it is providing the polarizing plate and display apparatus using such an antireflection film.
Another object of the present invention is to provide an antireflection film that achieves both low reflectance and neutralization of the color of reflected light, and further reduces the color shift with respect to film thickness error.
[0009]
[Means for Solving the Problems]
The present inventors can obtain an antireflection film exhibiting excellent scratch resistance by adding a silane coupling agent after hydrolysis / dehydration condensation in advance, and further, even if the addition amount is reduced, it is stable. It has been found that performance can be obtained and a great effect can be obtained. In addition, the inventors set the average value of the specular reflectance at 5 ° incidence in the wavelength region from 450 nm to 650 nm to 0.5% or less, and the CIE standard light source D in the region from the wavelength 380 nm to 780 nm.₆₅The color of specularly reflected light with respect to the incident light of 5 degrees is CIE1976L^*a^*b^*A in the color space^*, B^*Each value is -7 ≦ a^*≦ 7 and −10 ≦ b^*By making it within the range of ≦ 10, it is possible to prevent a reduction in visibility due to reflection of external light on the surface of the display device to a sufficient level, from the red purple that has been a problem with conventional multilayer antireflection films. It has been found that the color of blue-violet reflected light can be greatly reduced. The present invention has been made based on these findings.
[0010]
  That is, the present invention
(1) A low-refractive index layer having a refractive index lower than that of the support and mainly composed of a fluororesin on the transparent supportAnd adjacent high refractive index layerAn antireflective film having
The fluorine-containing resin,It is a fluorine-containing resin that is cured by heat or ionizing radiation.And a fluorine-containing copolymer having as a structural unit a fluorine-containing monomer and a monomer for imparting a crosslinkable group,
AboveLow refractive index layer andHigh refractive index layer, Hydrolyzate of organosilane represented by the following general formula (1) and / or partial condensate thereof, And metal oxide fine particlesContainsAnd
The high refractive index layer contains a hydrolyzate of organosilane represented by the following general formula (1) and / or a partial condensate thereof, metal oxide fine particles, a heat or ionizing radiation curable monomer, and an initiator. The coating composition is applied on the transparent support and cured by heat and / or ionizing radiation.An antireflection film characterized by
General formula (1)
      (R)_m-Si (X)_4-m                      (1)
(In the formula, R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. X represents a hydroxyl group or a hydrolyzable group. M represents an integer of 1 to 3.)
(1-2)In the low refractive index layer, the content of the hydrolyzate of organosilane represented by the general formula (1) and / or the partial condensate thereof is 0.1 to 50% by mass of the total solid content of the containing layer. It is characterized by beingThe antireflection film as described in (1),
(2)In the high refractive index layer, the content of the hydrolyzate of organosilane represented by the general formula (1) and / or the partial condensate thereof is 0.001 to 50% by mass of the total solid content of the containing layer. is there(1)Or (1-2)Antireflection film according to item,
(3)In the low refractive index layer, the content of the hydrolyzate of organosilane represented by the general formula (1) and / or the partial condensate thereof with respect to the fluororesin is 5 to 100% by mass.(1), (1-2)Or the antireflection film according to item (2),
[0011]
(4) A layer containing the hydrolyzate of organosilane represented by the general formula (1) and / or a partial condensate thereof in at least one of the low refractive index layer and / or the layer adjacent thereto. The organosilane compound represented by the general formula (1), a hydrolyzate thereof, or a partial condensate thereof is contained in the adjacent layer of any one of (1) to (3), Anti-reflection film,
(5) The metal oxide fine particles are contained in the layer containing the organosilane compound represented by the general formula (1), a hydrolyzate thereof, or a partial condensate thereof, according to the item (4), Antireflection film,
(6) In the antireflection film, the average value of the specular reflectance at 5 degrees incidence in the wavelength region from 450 nm to 650 nm is 0.5% or less, and the CIE standard light source D in the region from 380 nm to 780 nm is used.₆₅The color of specularly reflected light with respect to the incident light of 5 degrees is CIE1976L^*a^*b^*A in the color space^*, B^*Each value is -7 ≦ a^*≦ 7 and −10 ≦ b^*The antireflection film according to any one of (1) to (5), wherein ≦ 10 is satisfied,
[0012]
(7) In the antireflection film, a^*, B^*Each value is 0 ≦ a^*≦ 5 and −7 ≦ b^*In the range of ≦ 0, the antireflection film according to item (6),
(8) The antireflection film as described in the above item (6), wherein in the antireflection film, an average value in a wavelength region from 450 nm to 650 nm of the specular reflectance at 5 degrees incidence is 0.4% or less. the film,
(9) The antireflection film according to (8), wherein the antireflection film has an average value of a specular reflectance in a wavelength region from 450 nm to 650 nm at 5 ° incidence of 0.3% or less. the film,
(10) Each layer on the transparent support was formed by applying a coating composition containing a film-forming solute and at least one solvent, drying the solvent, curing with heat and / or ionizing radiation. The antireflection film according to any one of (1) to (9), wherein
(11) Between the low refractive index layer and the transparent support, a high refractive index layer having a refractive index higher than that of the support in order from the low refractive index layer side, an intermediate between the support and the high refractive index layer. The antireflective film according to any one of (1) to (10), wherein substantially three layers having different refractive indexes are formed, a middle refractive index layer having a refractive index,
[0013]
(12) In the antireflection film, the medium refractive index layer is represented by the following formula (I), the high refractive index layer is represented by the following formula (II), and the low refractive index layer is represented by the following formula (III) with respect to the design wavelength λ. The antireflection film as described in the item (11), wherein the antireflection film is satisfied,
(Lλ / 4) × 0.80 <n1d1 <(lλ / 4) × 1.00 (I)
(Mλ / 4) × 0.75 <n2d2 <(mλ / 4) × 0.95 (II)
(Nλ / 4) × 0.95 <n3d3 <(nλ / 4) × 1.05 (III)
Where λ is the wavelength of visible light (for example, 500 nm), l is 1, n1 is the refractive index of the medium refractive index layer, and d1 is the layer thickness (nm ), M is 2, n2 is the refractive index of the high refractive index layer, and d2 is the layer thickness (nm) of the high refractive index layer, n is 1, and n3 is the low refractive index. The refractive index of the layer, and d3 is the layer thickness (nm) of the low refractive index layer)
(13) For a transparent support having a refractive index of 1.45 to 1.55, n1 is 1.60 to 1.65, n2 is 1.85 to 1.95, and n3 is 1.35 to 1.5. The antireflective film according to (12), which has a refractive index of 45,
(14) For a transparent support having a refractive index of 1.55-1.68, n1 is 1.65 to 1.75, n2 is 1.85 to 2.05, and n3 is 1.35 to 1.75. The antireflective film according to (12), which has a refractive index of 45,
(15) Ultrafine particles, an anionic dispersant, wherein the high refractive index layer of the antireflection film contains at least one metal oxide selected from oxides of Ti, Zr, In, Zn, Sn, and Sb, It is formed by applying a coating composition containing a curable resin having a trifunctional or higher functional polymerizable group and a polymerization initiator, drying the solvent, curing by heat and / or ionizing radiation (11 ) To (14), the antireflection film according to any one of
[0014]
(16) The low refractive index layer of the antireflection film has a dynamic friction coefficient of 0.15 or less and a contact angle of pure water of 100 degrees or more, (1) to (15) An antireflection film as described in
(17) The antireflection film as described in any one of (1) to (16), which has at least one hard coat layer between the low refractive index layer and the transparent support,
(18) The antireflection film as described in any one of (1) to (17), which has at least one forward scattering layer between the low refractive index layer and the transparent support,
(19) CIE standard light source D in the wavelength region from 380 nm to 780 nm in any two places 10 cm apart in the TD direction or MD direction₆₅The color unevenness of the regular reflected light with respect to the incident light of 5 degrees is CIE1976L^*a^*b^*ΔE of color space^* _abThe antireflection film according to any one of (1) to (18), characterized in that the value is less than 2.
[0015]
(20) The vertical peel charge amount measured at normal temperature and humidity for either triacetyl cellulose or polyethylene terephthalate is -200 pC (picocoulomb) / cm²~ + 200pC (picocoulomb) / cm²And the surface resistance value is 1 × 10¹¹The antireflection film according to any one of (1) to (19), wherein the antireflection film is characterized by being Ω / □ or more,
(21) The antireflection film as described in any one of (1) to (20), wherein the transparent support is a triacetyl cellulose film, a polyethylene terephthalate film, or a polyethylene naphthalate film,
(22) The constituent layer on the support of the antireflection film described in any one of (1) to (21) is sent out once, forming the optical thin film, and winding the film. A method for producing an antireflection film, characterized by being formed in the process of
[0016]
(23) A polarizing plate in which two surface protective films are bonded to the front and back surfaces of a polarizer, and the antireflection film according to any one of (1) to (21) is at least one surface protective film A polarizing plate characterized by being used as
(24) having an optical compensation film having an optical compensation layer comprising at least one optically anisotropic layer on the surface opposite to the antireflection film with respect to the polarizer of the surface protective film, The optically anisotropic layer is a birefringent layer made of a compound having a discotic structural unit, the disc surface of the discotic structural unit is inclined with respect to the surface protective film surface, and the discotic structural unit The polarizing plate according to item (23), wherein an angle formed by the disk surface of the surface protective film surface is changed in the depth direction of the optically anisotropic layer,
(25) A polarizing plate in which two surface protective films are bonded to the front and back surfaces of a polarizer, and the low refractive index layer of the antireflection film according to any one of (1) to (21) is formed. Later, a polarizing plate characterized in that an antireflection film obtained by saponifying the back surface of the film by immersing it in an alkaline solution at least once is used as a surface protective film on at least one surface,
(26) A polarizing plate in which two surface protective films are bonded to the front and back surfaces of a polarizer, and the low refractive index layer of the antireflection film according to any one of (1) to (21) is formed. Before or after forming the surface to be coated, an alkali solution is applied to the surface of the antireflection film opposite to the surface on which the low refractive index layer is formed, and heated, washed and / or neutralized, so that only the back surface of the film is formed. A polarizing plate characterized by using an antireflection film saponified as a surface protective film on at least one side,
[0017]
(27) An image display device having at least one antireflection film according to any one of (1) to (21) or a polarizing plate according to any one of (23) to (26),
(28) A TN, STN, VA, IPS, OCB mode transmissive, reflective, or transflective liquid crystal display having at least one polarizing plate according to any one of (23) to (26) apparatus,
(29) A transmissive or transflective liquid crystal display device having at least one polarizing plate according to any one of (23) to (26), and a polarizing plate and a backlight opposite to the viewing side A liquid crystal display device, wherein a polarization separation film having a polarization selective layer is disposed between
(30) Transmission or semi-transmission characterized in that a λ / 4 plate is disposed on the transparent protective film opposite to the antireflection film of the polarizing plate according to any one of (23) to (26) Liquid crystal device, and
(31) An organic EL display device comprising a λ / 4 plate disposed on a transparent protective film opposite to the antireflection film of the polarizing plate according to any one of (23) to (26)
Is to provide.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
A basic configuration of an antireflection film suitable as an embodiment of the present invention will be described with reference to the drawings.
[0019]
[Formation of antireflection film]
FIG. 1 is a schematic cross-sectional view showing the basic layer structure of the antireflection film of the present invention. The antireflection film of the present invention preferably has a layer structure in the order of the transparent support 1, the hard coat layer 2, the medium refractive index layer 3, the high refractive index layer 4, and the low refractive index layer 5. Such an antireflection film having a three-layer structure has an optical film thickness of each of the medium refractive index layer, the high refractive index layer, and the low refractive index layer, that is, the product of the refractive index and the film thickness with respect to the design wavelength λ. JP-A-59-50401 describes that nλ / 4 is preferably around or a multiple thereof.
However, in order to realize the low reflectance and the reflectance characteristic of the reflected light of the present invention, the middle refractive index layer particularly satisfies the following formula (I) with respect to the design wavelength λ. The layer must satisfy the following formula (II), and the low refractive index layer must satisfy the following formula (III).
[0020]
(Lλ / 4) × 0.80 <n1d1 <(lλ / 4) × 1.00 (I)
[0021]
(Mλ / 4) × 0.75 <n2d2 <(mλ / 4) × 0.95 (II)
[0022]
(Nλ / 4) × 0.95 <n3d3 <(nλ / 4) × 1.05 (III)
[0023]
Where λ is the wavelength of visible light (eg 500 nm), l is 1, n1 is the refractive index of the medium refractive index layer, and d1 is the layer thickness (nm) of the medium refractive index layer , M is 2, n2 is the refractive index of the high refractive index layer, and d2 is the layer thickness (nm) of the high refractive index layer, n is 1, and n3 is the refractive index of the low refractive index layer. And d3 is the layer thickness (nm) of the low refractive index layer. Furthermore, for example, n1 is 1.60 to 1.65 and n2 is 1 for a transparent support having a refractive index of 1.45 to 1.55 made of triacetylcellulose (refractive index: 1.49). .85 to 1.95, n3 must have a refractive index of 1.35 to 1.45, for example, a refractive index of 1.55 to 1.65 made of polyethylene terephthalate (refractive index: 1.66). N1 is 1.65 to 1.75, n2 is 1.85 to 2.05, and n3 is 1.35 to 1.45.
[0024]
Equivalent film in which a plurality of layers having a refractive index higher than the set refractive index and a layer having a low refractive index are combined even when the materials of the medium refractive index layer and the high refractive index layer having the above refractive index cannot be selected. By using this principle, it is possible to form a layer that is optically equivalent to a medium refractive index layer or a high refractive index layer having a set refractive index, and this can be used to realize the reflectance characteristics in the present invention. it can. The term “substantially three layers” in this specification means to include an antireflection layer composed of terms having different refractive indexes of four layers and five layers using such an equivalent film.
[0025]
The reflectance characteristics in the present invention achieved by the layer configuration as described above can achieve both low reflection and a reduction in the color of reflected light. For example, when applied to the outermost surface of a liquid crystal display device A display device having unprecedented visibility can be obtained. By reducing the average value of the specular reflectivity in the wavelength region from 450 nm to 650 nm at 5 ° incidence to 0.5% or less, the deterioration of visibility due to reflection of external light on the display device surface is prevented to a sufficient level. it can. The average value is preferably 0.4% or less, more preferably 0.3% or less. In addition, the CIE standard light source D in the wavelength region from 380 nm to 780 nm₆₅The color of specularly reflected light with respect to the incident light of 5 degrees is CIE1976L^*a^*b^*A in the color space^*, B^*Each value is -7 ≦ a^*≦ 7 and −10 ≦ b^*By making it within the range of ≦ 10, the tint of the reflected light of red purple to blue violet, which has been a problem in the conventional multilayer antireflection film, is reduced, more preferably 0 ≦ a^*≦ 5 and −7 ≦ b^*The color tone is drastically reduced by being within the range of ≦ 0, and when applied to a liquid crystal display device, the color tone when external light with high brightness, such as an indoor fluorescent lamp, is slightly reflected. Neutral so you don't have to worry. a^*> 7 is strong red and a^*<-7 is not preferable because the cyan color becomes strong. B^*<-7 is strong blue, b^*If it is> 0, yellowishness becomes strong, which is not preferable.
[0026]
Specular reflectance and color are measured by attaching an adapter ARV-474 (trade name) to a spectrophotometer V-550 (trade name, manufactured by JASCO Corporation) and entering in the wavelength range of 380 to 780 nm. It is possible to measure the specular reflectance at an exit angle of -5 degrees at an angle of 5 °, calculate the average reflectance of 450 to 650 nm, and evaluate the antireflection property. Further, from the measured reflection spectrum, the CIE standard light source D₆₅CIE1976L representing the color of regular reflected light with respect to 5 degree incident light^*a^*b^*L of color space^*Value, a^*Value, b^*The value can be calculated and the color of the reflected light can be evaluated.
[0027]
Furthermore, since the color of the reflected light is greatly reduced as described above, the color unevenness of the reflected light due to the film thickness unevenness of the antireflection layer is also greatly reduced. That is, the allowable range of film thickness unevenness is widened, the manufacturing yield is increased, and the cost can be further reduced. Quantitatively, the CIE standard light source D in the wavelength range of 380 nm to 780 nm at any two locations 10 cm apart in the TD direction (direction orthogonal to the support longitudinal direction) or MD direction (support longitudinal direction).₆₅CIE 1976L can be represented by uneven color of regular reflected light with respect to 5 degree incident light.^*a^*b^*ΔE of color space^* _abThe value is preferably less than 2, and less than 1.5 is more preferable because unevenness cannot be completely detected by human eyes.
[0028]
The antireflection film of the present invention has a vertical peeling charge of −200 pC (picocoulomb) / cm measured at normal temperature and humidity with respect to either triacetylcellulose (TAC) or polyethylene terephthalate (PET).²~ + 200pC (picocoulomb) / cm²It is preferable from the viewpoint of dust resistance. More preferably -100 pC / cm²~ + 100pC / cm²And more preferably −50 pC / cm²~ + 50pC / cm²And most preferably 0 pC / cm²It is. Here, the unit of pC (picocoulomb) is 10^-12Coulomb.
More preferably, the vertical peel charge measured at a room temperature of 10% RH is −100 pC / cm.²~ + 100pC / cm²And more preferably −50 pC / cm²~ + 50pC / cm²And most preferably 0 pC / cm²It is.
[0029]
The measurement method of the vertical peeling charge is as follows.
The measurement sample is left in advance for 2 hours or more in an environment of measurement temperature and humidity. The measuring device is composed of a table on which a measurement sample is placed and a head that can hold a partner film and repeatedly press and peel the measurement sample from above, and an electrometer for measuring the charge amount is connected to the head. Place the antireflection film to be measured on the table and attach TAC or PET to the head. After neutralizing the measurement portion, the head is pressure-bonded to the measurement sample and peeled off repeatedly, and the charge values at the first peeling and the fifth peeling are read and averaged. This is repeated for three samples by changing the sample, and the average of all the samples is defined as vertical peeling charge.
[0030]
Depending on the type of the counterpart film or measurement sample, there are cases where it is positively charged and negatively charged, but the problem is the magnitude of the absolute value.
In general, the absolute value of charging is larger in a low humidity environment. The antireflection film of the present invention has a small absolute value.
[0031]
The antireflection film of the present invention is excellent in dust resistance since the absolute value of the vertical peeling charge at normal temperature and normal humidity and normal temperature of 10% RH is small.
In order to set the value of the vertical peeling charge within the above range, the ratio of various elements on the surface of the antireflection film is adjusted.
[0032]
The surface resistance value of the antireflection film of the present invention is 1 × 10.¹¹Ω / □ or more, preferably 1 × 10¹²Ω / □ or more. The measuring method of the surface resistance value is a circular electrode method described in JIS. That is, the current value one minute after voltage application is read to determine the surface resistance value (SR).
In the present invention, reducing the surface resistance value, for example, 1 × 10^TenThe idea is fundamentally different from the method of improving the dust resistance (prevention of dust adhesion) by setting it to Ω / □ or less. This method is not adopted because the image display quality is deteriorated. In the present invention, the absolute value of the vertical peeling charge is reduced by the above-described method. Therefore, it is not necessary to reduce the surface resistance value, and the surface resistance value is 1 × 10.¹¹Ω / □ or more can be achieved, and the image display quality does not deteriorate.
[0033]
As the transparent support used in the antireflection film of the present invention, it is preferable to use a plastic film. Examples of plastic film materials include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose), polyamides, polycarbonates, polyesters (eg, polyethylene terephthalate, polyethylene naphthalate). , Poly-1,4-cyclohexanedimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4′-dicarboxylate, polybutylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, Polypropylene, polyethylene, polymethylpentene), polysulfone, polyethersulfone, polyarylate, polyetherimide, polymethylmethacrylate It includes over preparative and polyether ketones.
[0034]
In particular, when the antireflection film of the present invention is used as one side of a surface protective film of a polarizing plate for use in a liquid crystal display device, an organic EL display device or the like, triacetyl cellulose is preferably used. As the triacetyl cellulose film, a known film such as TAC-TD80U (trade name, manufactured by Fuji Photo Film Co., Ltd.) or a film published in published technical report number 2001-1745 is preferably used. In addition, polyethylene terephthalate or polyethylene naphthalate is preferable when it is used by being bonded to a glass substrate or the like for use in a flat CRT or PDP.
[0035]
The light transmittance of the transparent support is preferably 80% or more, and more preferably 86% or more. The haze of the transparent support is preferably 2.0% or less, and more preferably 1.0% or less. The refractive index of the transparent support is preferably 1.4 to 1.7. The thickness of the transparent support of the present invention is not particularly limited, but is preferably 30 to 150 μm, more preferably 40 to 130 μm, and still more preferably 70 to 120 μm.
[0036]
In order to obtain high scratch resistance by improving adhesion between the plurality of optical thin films, at least one of the plurality of optical thin films including at least one low refractive index layer according to the present invention is used. It contains a hydrolyzate of the compound and / or a partial condensate thereof, a so-called sol component (hereinafter also referred to as such).
The organosilane compound is represented by the following general formula (1).
General formula (1)
(R^Ten)_m-Si (X)_4-m                      (1)
[0037]
In the general formula (1), R^TenRepresents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, t-butyl, sec-butyl, hexyl, decyl, hexadecyl and the like. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable.
[0038]
X represents a hydroxyl group or a hydrolyzable group, and examples of the hydrolyzable group include an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group and an ethoxy group), halogen (for example, Cl, Br, I, etc.) or R²COO (R²Is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. For example, CH_ThreeCOO, C₂H_FiveCOO etc. are mentioned), preferably an alkoxy group, particularly preferably a methoxy group or an ethoxy group.
m represents an integer of 1 to 3. R^TenOr, when there are multiple Xs, multiple Rs^TenAlternatively, Xs may be the same or different. m is preferably 1 or 2, particularly preferably 1.
[0039]
R^TenThere are no particular restrictions on the substituents contained in, but halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), hydroxyl groups, mercapto groups, carboxyl groups, epoxy groups, alkyl groups (methyl, ethyl, i-propyl, propyl) , T-butyl etc.), aryl group (phenyl, naphthyl etc.), aromatic heterocyclic group (furyl, pyrazolyl, pyridyl etc.), alkoxy group (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy) Etc.), alkylthio group (methylthio, ethylthio etc.), arylthio group (phenylthio etc.), alkenyl group (vinyl, 1-propenyl etc.), acyloxy group (acetoxy, acryloyloxy, methacryloyloxy etc.), alkoxycarbonyl group (methoxycarbonyl, Ethoxycarbonyl, etc.), ants Ruoxycarbonyl group (phenoxycarbonyl etc.), carbamoyl group (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl etc.), acylamino group (acetylamino, benzoylamino, acrylicamino, Methacrylamino and the like, and these substituents may be further substituted.
[0040]
R^TenWhen there is a plurality, it is preferable that at least one is a substituted alkyl group or a substituted aryl group, and among them, an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (2) is preferable.
General formula (2)
[0041]
[Chemical 1]

[0042]
In the general formula (2), R¹Represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom or a chlorine atom. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group. A hydrogen atom, methyl group, methoxy group, methoxycarbonyl group, cyano group, fluorine atom or chlorine atom is preferred, a hydrogen atom, methyl group, methoxycarbonyl group, fluorine atom or chlorine atom is more preferred, and a hydrogen atom or methyl group is particularly preferred preferable.
[0043]
Y represents a single bond or an ester group, an amide group, an ether group or a urea group. A single bond, an ester group or an amide group is preferred, a single bond or an ester group is more preferred, and an ester group is particularly preferred.
[0044]
L represents a divalent linking chain. Specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (for example, ether, ester, amide, etc.) inside, and a linking group inside. A substituted or unsubstituted arylene group having 2 to 10 carbon atoms, a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and 3 to 3 carbon atoms having a linking group inside. 10 alkylene groups are preferred, an unsubstituted alkylene group, an unsubstituted arylene group, an alkylene group having an ether or ester linking group inside is more preferred, an unsubstituted alkylene group, an alkylene having an ether or ester linking group inside The group is particularly preferred. Examples of the substituent include a halogen atom, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.
[0045]
n represents 0 or 1. When there are a plurality of Xs, the plurality of Xs may be the same or different. n is preferably 0.
R^TenIs synonymous with the general formula (1), preferably a substituted or unsubstituted alkyl group or an unsubstituted aryl group, and more preferably an unsubstituted alkyl group or an unsubstituted aryl group.
X has the same meaning as in formula (1), preferably a halogen atom, a hydroxyl group, or an unsubstituted alkoxy group, more preferably a chlorine atom, a hydroxyl group, or an unsubstituted alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, or An alkoxy group having 1 to 3 carbon atoms is more preferable, and a methoxy group is particularly preferable.
[0046]
Two or more compounds of the general formula (1) or the general formula (2) may be used in combination. Although the specific example of a compound represented by General formula (1) or General formula (2) below is shown, this invention is not limited to these.
[0047]
[Chemical 2]

[0048]
[Chemical 3]

[0049]
[Formula 4]

[0050]
[Chemical formula 5]

[0051]
[Chemical 6]

[0052]
[Chemical 7]

[0053]
[Chemical 8]

[0054]
Among these specific examples, (M-1), (M-2), (M-25) and the like are particularly preferable.
[0055]
In order to acquire the effect of this invention, 30-100 mass% is preferable, as for content of the organosilane in the hydrolyzate of organosilane and / or its partial condensate, 50-100 mass% is more preferable, 70- 100 mass% is still more preferable, and 90-100 mass% is especially preferable. If the content of organosilane is less than 30% by mass, solid content is generated, the liquid becomes cloudy, the pot life is deteriorated, the molecular weight is difficult to control (increase in molecular weight), or the polymerizable group is contained. Since the amount is small, it is not preferable because it is difficult to improve the performance (for example, scratch resistance of the antireflection film) when the polymerization treatment is performed.
[0056]
The weight average molecular weight of the hydrolyzate of organosilane and / or its partial condensate is preferably 1000 to 20000, more preferably 1000 to 10,000, and even more preferably 1100 to 5000, when components having a molecular weight of less than 300 are excluded. 1200 to 3000 is more preferable, and 1200 to 2000 is more preferable.
Of the components having a molecular weight of 300 or more in the hydrolyzate of organosilane and / or its partial condensate, the component having a molecular weight of more than 20000 is preferably 20% by mass or less, more preferably 15% by mass or less. More preferably, it is 10 mass% or less, More preferably, it is 6 mass% or less, It is especially preferable that it is 4 mass% or less.
Moreover, it is preferable that the component of molecular weight 1000-20000 is 80 mass% or more among the components of molecular weight 300 or more in the hydrolyzate of organosilane and / or its partial condensate. When it is less than 80% by mass, the antireflection film containing such a hydrolyzate of organosilane and / or a partial condensate thereof may be inferior in transparency and adhesion.
[0057]
Here, the weight average molecular weight and molecular weight are converted into polystyrene by GTH analyzer using TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL columns (all trade names, manufactured by Tosoh Corporation), solvent THF and differential refractometer detection. The content is the area% of the peak in the molecular weight range when the peak area of the component having a molecular weight of 300 or more is defined as 100%.
The dispersity (weight average molecule / number average molecular weight) is preferably 3.0 to 1.1, more preferably 2.5 to 1.1, still more preferably 2.0 to 1.1, and 1.5 to 1. 1 is particularly preferred.
[0058]
Of hydrolyzate and / or partial condensate of organosilane²⁹The state in which X in the general formula (1) is condensed in the form of -OSi can be confirmed by Si-NMR analysis.
At this time, the ratio (T3 / T2) of the case where three bonds of Si are condensed in the form of -OSi (T3) and the case where two bonds of Si are condensed in the form of -OSi (T2). In the case of the degree of condensation, the degree of condensation is preferably 0.5 to 3.5, more preferably 0.5 to 3.0, and particularly preferably 0.7 to 2.5.
If it is less than 0.5, hydrolysis and condensation are not sufficient, and monomer components increase, so that curing is not sufficient. If it is more than 3.5, hydrolysis and condensation proceed too much, and hydrolyzable groups are consumed. For this reason, the interaction between the binder polymer, the resin substrate, the inorganic fine particles and the like is lowered, and even if these are used, it is difficult to obtain the effect.
[0059]
The hydrolysis and / or condensation reaction of the organosilane can be performed in the absence of a solvent or in a solvent, and the curable composition of the present invention can be produced. When a solvent is used, the concentration of the hydrolyzate of organosilane and / or the partial condensate thereof can be appropriately determined. As the solvent, an organic solvent is preferably used in order to uniformly mix the components. For example, alcohols, aromatic hydrocarbons, ethers, ketones, esters and the like are preferable.
The solvent preferably dissolves the organosilane and the catalyst. In addition, it is preferable in the process that an organic solvent is used as a coating solution or a part of the coating solution, and those that do not impair the solubility or dispersibility when mixed with other materials such as a fluorine-containing resin are preferable.
[0060]
Among these, examples of the alcohols include monohydric alcohols and dihydric alcohols. Among these, monohydric alcohols are preferably saturated aliphatic alcohols having 1 to 8 carbon atoms. Specific examples of these alcohols include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol. Examples thereof include monobutyl ether and ethylene glycol monoethyl ether acetate.
[0061]
Specific examples of aromatic hydrocarbons include benzene, toluene and xylene, specific examples of ethers include tetrahydrofuran and dioxane, and specific examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Specific examples of esters such as diisobutylketone and the like include ethyl acetate, propyl acetate, butyl acetate, and propylene carbonate.
These organic solvents can be used alone or in combination of two or more. The concentration of the solid content with respect to the solvent in the reaction is not particularly limited, but is usually in the range of 1 to 90% by mass, and preferably in the range of 20 to 70% by mass.
[0062]
The hydrolysis and / or condensation reaction of the organosilane is preferably performed in the presence of a catalyst. Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid; inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia; triethylamine, Examples include organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium. From the viewpoint of production stability of the sol solution and storage stability of the sol solution, an acid catalyst is used in the present invention. (Inorganic acids and organic acids) are preferred. Among inorganic acids, hydrochloric acid, sulfuric acid, and organic acids preferably have an acid dissociation constant in water (pKa value (25 ° C.)) of 4.5 or less, and an acid dissociation constant in hydrochloric acid, sulfuric acid, or water of 3.0 or less. More preferred is an organic acid, hydrochloric acid, sulfuric acid, an organic acid having an acid dissociation constant of 2.5 or less in water is more preferred, an organic acid having an acid dissociation constant in water of 2.5 or less is more preferred, and methanesulfonic acid Further, oxalic acid, phthalic acid, and malonic acid are more preferable, and oxalic acid is particularly preferable.
[0063]
The hydrolysis and / or condensation reaction is usually performed by adding 0.3 to 2 mol, preferably 0.5 to 1 mol of water with respect to 1 mol of the hydrolyzable group of organosilane, and in the presence of the above solvent or It is carried out by stirring at 25-100 ° C. in the absence and preferably in the presence of a catalyst.
When the hydrolyzable group is an alkoxide and the catalyst is an organic acid, the carboxyl group or sulfo group of the organic acid supplies protons, so the amount of water added can be reduced, and the amount of the alkoxide group of the organosilane can be reduced to 1 mol. The amount of water added is 0 to 2 mol, preferably 0 to 1.5 mol, more preferably 0 to 1 mol, and particularly preferably 0 to 0.5 mol. When alcohol is used as the solvent, it is also preferred that substantially no water is added.
[0064]
The catalyst is used in an amount of 0.01 to 10 mol%, preferably 0.1 to 5 mol%, based on the hydrolyzable group when the catalyst is an inorganic acid, and when the catalyst is an organic acid, The optimum amount used varies depending on the amount of water added, but in the case of adding water, it is 0.01 to 10 mol%, preferably 0.1 to 5 mol% with respect to the hydrolyzable group. When water is not added, it is 1 to 500 mol%, preferably 10 to 200 mol%, more preferably 20 to 200 mol%, still more preferably 50 to 150 mol%, based on the hydrolyzable group. And particularly preferably 50 to 120 mol%. The reaction is carried out by stirring at 25 to 100 ° C., but it is preferably adjusted as appropriate depending on the reactivity of the organosilane.
[0065]
The appropriate content of the organosilane sol differs depending on the layer to be added, but the added amount of the low refractive index layer is preferably 0.1 to 50% by mass of the total solid content of the containing layer (added layer). 5-20 mass% is more preferable, and 1-10 mass% is especially preferable. The amount added to the optical thin film layer other than the low refractive index layer is preferably 0.001 to 50% by mass, more preferably 0.01 to 20% by mass, based on the total solid content of the containing layer (added layer). 10 mass% is more preferable, and 1-5 mass% is especially preferable.
[0066]
The amount of the organosilane sol used in the low refractive index layer is preferably 5 to 100% by mass, more preferably 5 to 40% by mass, still more preferably 8 to 35% by mass, and more preferably 10 to 30% by mass. Is particularly preferred. If the amount used is too small, it is difficult to obtain the effect of the present invention, and if the amount used is too large, the refractive index increases or the shape / surface shape of the film deteriorates.
When the organosilane is added to the low refractive index layer, it is more preferable that the layer adjacent to the low refractive index layer contains inorganic oxide fine particles because the adhesion between the layers increases. Similarly, when the organosilane is added to the high refractive index layer, it is more preferable that the adjacent low refractive index layer and / or medium refractive index layer contain inorganic oxide fine particles.
[0067]
The medium refractive index layer and the high refractive index layer are coated with a coating composition containing inorganic fine particles having a high refractive index, a thermal or ionizing radiation curable monomer, an initiator, preferably the above organosilane sol, and a solvent. Formed by drying, curing with heat and / or ionizing radiation. As the inorganic fine particles, those composed of at least one metal oxide selected from oxides of Ti, Zr, In, Zn, Sn, and Sb are preferable. The medium refractive index layer and the high refractive index layer thus formed are excellent in scratch resistance and adhesion as compared with those obtained by applying and drying a polymer solution having a high refractive index. In order to ensure dispersion stability, film strength after curing, etc., a polyfunctional (meta-functional) as described in JP-A-11-153703, US Pat. No. 6,210,858, etc. It is preferable that an acrylate monomer and an anionic group-containing (meth) acrylate dispersant are contained in the coating composition.
[0068]
The average particle diameter of the inorganic fine particles is preferably 1 to 100 nm as an average particle diameter measured by a Coulter counter method. If it is 1 nm or less, the specific surface area is too large, so that the stability in the dispersion is poor, which is not preferable. When the thickness is 100 nm or more, scattering of visible light due to a difference in refractive index from the binder occurs, which is not preferable. The haze of the high refractive index layer and the medium refractive index layer is preferably 3% or less, more preferably 1% or less, and still more preferably 0.5% or less.
[0069]
The low refractive index layer contains, as a main component, a fluorine-containing resin that is cured by heat or ionizing radiation. When the organosilane sol and the inorganic filler are contained, the adhesion to other layers and the strength of the self-layer are improved, so that the scratch resistance is remarkably improved, which is preferable. Further, when the above-mentioned organosilane compound, its hydrolyzate or its partial condensate is contained in another optical thin film layer adjacent to the low refractive index layer, the adhesion between the layers is preferably improved, and it is adjacent to the low refractive index layer. When the organosilane sol is contained in both the other optical thin film layer and the low refractive index layer, adhesion between the layers is particularly preferable.
The dynamic friction coefficient of the cured product is preferably 0.03 to 0.15, and the contact angle with respect to pure water is preferably 100 to 120 degrees. When the coefficient of dynamic friction is higher than 0.15, the surface tends to be damaged when rubbed, which is not preferable. In addition, when the contact angle with respect to pure water is less than 100 degrees, fingerprints, oil stains, and the like are likely to adhere, which is not preferable from the viewpoint of antifouling properties.
As the curable fluorine-containing resin, in addition to a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane), a fluorine-containing monomer and a crosslinkable group are added. And a fluorine-containing copolymer having a monomer as a constituent unit.
[0070]
Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc. ), (Meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (trade name, manufactured by Osaka Organic Chemicals) and M-2020 (trade name, manufactured by Daikin), etc.), fully or partially fluorinated vinyl ether Among these, hexafluoropropylene is particularly preferable from the viewpoint of low refractive index and ease of handling of the monomer.
[0071]
As a monomer for imparting a crosslinkable group, in addition to a (meth) acrylate monomer having a crosslinkable functional group in the molecule like glycidyl methacrylate, it has a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc. ) Acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.). JP-A-10-25388 and JP-A-10-147739 disclose that the latter can introduce a crosslinked structure after copolymerization, and is particularly preferable.
[0072]
Further, not only a polymer having the above-mentioned fluorine-containing monomer as a structural unit but also a copolymer with a monomer not containing a fluorine atom may be used. There are no particular limitations on the monomer units that can be used in combination. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2) -Ethylhexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl) Vinyl ether), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, Krilo can be exemplified nitrile derivatives, disclosed by Japanese Patent Laid-Open 10-25388 and JP-10-147739 JP.
[0073]
Furthermore, for the purpose of imparting scratch resistance and antifouling properties, it is preferable that a polysiloxane structure is introduced into the fluorine-containing polymer. The method for introducing the polysiloxane structure is not limited, but for example, as described in JP-A-11-189621, JP-A-11-228631, and JP-A-2000-313709, a polysiloxane block can be prepared using a silicone macroazo initiator. A method of introducing a polymerization component and a method of introducing a polysiloxane graft copolymer component using a silicone macromer as described in JP-A-2-251555 and JP-A-2-308806 are preferred. These polysiloxane components are preferably 0.5 to 10% by mass in the polymer, and particularly preferably 1 to 5% by mass.
[0074]
For imparting antifouling properties, reactive group-containing polysiloxanes other than the above (for example, KF-100T, X-22-169AS, KF-102, X-22-3701IE, X-22-164B, X-22- 5002, X-22-173B, X-22-174D, X-22-167B, X-22-161AS (above trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), AK-5, AK-30, AK-32 (above A trade name, manufactured by Toa Gosei Co., Ltd.), Silaplane FM0275, Silaplane FM0721 (manufactured by Chisso Corporation), etc.) is also preferred. In this case, these polysiloxanes are preferably added in the range of 0.5 to 10% by mass of the total solid content of the low refractive index layer, and particularly preferably 1 to 5% by mass.
[0075]
As the inorganic filler used in the low refractive index layer, those having a low refractive index are preferably used. Preferred inorganic fillers are silica and magnesium fluoride, and silica is particularly preferable.
The average particle size of the inorganic filler is preferably 0.001 to 0.2 μm, and more preferably 0.001 to 0.05 μm. The particle size of the filler is preferably as uniform (monodispersed) as possible, but it is also possible to use two or more different types of monodispersed fillers in combination, particularly for the purpose of improving the scratch resistance. It is done.
[0076]
The refractive index of the fluorine-containing resin used for forming the low refractive index layer is preferably as low as possible from the viewpoint of antireflection properties, but the scratch resistance deteriorates as the refractive index of the fluorine-containing resin is lowered. Therefore, by optimizing the refractive index of the fluorine-containing resin and the amount of the inorganic filler added, the best balance between scratch resistance and low refractive index can be found. The blending ratio of the fluororesin and the inorganic filler is preferably 95: 5 to 50:50, more preferably 90:10 to 60:40.
Among the above-mentioned inorganic fillers, particularly preferred silica fillers may be silica sol dispersed in a commercially available organic solvent as it is added to the coating composition as it is, or various commercially available silica powders dispersed in an organic solvent. Good.
[0077]
The antireflection film may further be provided with a hard coat layer, a forward scattering layer, an antistatic layer, an undercoat layer and a protective layer.
The hard coat layer is provided for imparting scratch resistance to the transparent support. The hard coat layer also has a function of strengthening the adhesion between the transparent support and the layer thereon. The hard coat layer was obtained by adding an inorganic filler such as silica or alumina to a composition in which a polyfunctional acrylic monomer, an oligomer such as urethane acrylate or epoxy acrylate, or various polymerization initiators were dissolved in a solvent. It is preferably formed by applying a coating composition, drying a solvent, curing by heat and / or ionizing radiation. Details will be described later.
[0078]
The thickness of the hard coat layer is preferably 1 to 30 μm, more preferably 2 to 20 μm, and most preferably 3 to 10 μm.
The pencil hardness of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher.
The refractive index of the hard coat layer is preferably in the range of 1.45 to 1.8, and the difference from the refractive index of the support is preferably in the range of 0 to 0.3.
[0079]
The hard coat layer can be formed as a layer composed of an inorganic compound mainly composed of silicon dioxide, a layer composed of a saturated hydrocarbon or an organic compound such as a polymer having a polyether as a main chain, or a hybrid layer of inorganic / organic compounds. . A layer made of a polymer having a saturated hydrocarbon as the main chain is particularly preferred. The polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups.
[0080]
Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, pentaerythritol). Tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives (examples) 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, divinyl sulfone), acrylamide (eg, methylenebisacrylamide) and methacrylamide are included .
The polymer having a polyether as the main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound.
These monomers having an ethylenically unsaturated group need to be cured by a polymerization reaction by ionizing radiation or heat after coating.
[0081]
Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder polymer by the reaction of a crosslinkable group. Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. In the present invention, the cross-linking group is not limited to the above compound, and may be one showing reactivity as a result of decomposition of the functional group.
These compounds having a crosslinking group need to be crosslinked by heat after application.
[0082]
Further, inorganic fine particles may be added to the hard coat layer in order to adjust the refractive index and increase the curing strength of the film. The inorganic fine particles preferably have an average particle size of 0.001 to 0.5 μm, particularly preferably 0.001 to 0.2 μm. Examples of inorganic fine particles include silicon dioxide particles, titanium dioxide particles, aluminum oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc, kaolin and calcium sulfate particles. Silicon dioxide particles, titanium dioxide particles, aluminum oxide particles Is particularly preferred.
The addition amount of the inorganic fine particles is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30 to 60% by mass with respect to the total mass of the hard coat layer.
[0083]
The forward scattering layer is provided in order to give a viewing angle improvement effect when the viewing angle is inclined in the vertical and horizontal directions when applied to a liquid crystal display device. By dispersing fine particles having different refractive indexes in the hard coat layer, it can also serve as a hard coat function.
[0084]
In the case of imparting anti-glare properties to blur the reflection of the background by surface irregularities on the multilayer antireflection film by wet coating of the coating composition of the present invention, the surface irregularities containing mat particles etc. that are generally used It is preferable to form the surface uneven structure after forming the antireflection layer by an embossing method or the like rather than forming an antireflection layer on the layer having, because the film thickness uniformity improves and the antireflection performance improves. .
[0085]
Each layer of the antireflection film is formed by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, micro gravure method or extrusion coating method (US Pat. No. 2,681,294). According to the specification, it can be formed by coating. The microgravure method and the gravure method are preferable from the viewpoint of eliminating drying unevenness by minimizing the wet coating amount, and the gravure method is particularly preferable from the viewpoint of film thickness uniformity in the width direction. At least two layers of the plurality of optical thin films of the antireflection film of the present invention are formed by the steps of feeding the support film once, forming each optical thin film, and winding the film. It is preferable from the viewpoint of production cost. When the antireflection layer has a three-layer structure, it is preferable to form the three layers in one step. In such a manufacturing method, a plurality of coating stations and drying / curing zone sets, preferably the same number or more as the number of optical thin films, are cascaded between feeding and winding of the support film of the coating machine. This is achieved by providing.
[0086]
Instead of providing a plurality of application stations as described above, two or more layers may be applied simultaneously. For the method of simultaneous application, US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, 3,526,528, and Harasaki Yuji, “Coating Engineering”, page 253, Asakura Shoten (1973).
[0087]
A polarizing plate can be formed by bonding two antireflection films of the present invention to the front and back surfaces of a polarizer. In this case, it is preferable to use the antireflection film of the present invention as a surface protective film on at least one side of the polarizing plate.
When the antireflection film of the present invention is used as one side of the surface protective film of the polarizer, it is necessary to saponify the surface of the transparent support opposite to the surface on which the antireflection layer is formed with an alkali. . Specific means for the alkali saponification treatment can be selected from the following two. (1) is superior in that it can be processed in the same process as a general-purpose triacetylcellulose film, but since the surface of the antireflection film is saponified, the surface is alkali-hydrolyzed and the film deteriorates. The point that it becomes dirty when the liquid remains can be a problem. In that case, although it becomes a special process, (2) is excellent.
(1) After the antireflection layer is formed on the transparent support, the back surface of the film is saponified by immersing it in an alkaline solution at least once.
(2) Before or after the formation of the antireflection layer on the transparent support, the alkaline liquid is applied to the surface of the antireflection film opposite to the surface on which the antireflection film is formed, and is heated, washed and / or washed. By summing, only the back surface of the film is saponified.
[0088]
Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. In general, a polyvinyl alcohol film (hereinafter referred to as PVA) is preferably used as the iodine polarizer and the dye polarizer. PVA is usually saponified polyvinyl acetate, but modified PVA can also be used. A polarizing film is obtained by dyeing PVA. Examples of dyeing can be performed by any means such as a method of immersing a PVA film in an iodine-potassium iodide aqueous solution, application of iodine or a dye solution, or spraying. In the process of producing a polarizing film by stretching PVA, it is preferable to use an additive that crosslinks PVA, for example, boric acids. The transmittance of the polarizing plate is preferably in the range of 30 to 50% and more preferably in the range of 35 to 50% with respect to light having a wavelength of 550 nm. The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.
[0089]
As described in JP-A-8-50206, JP-A-2001-100043, and the like, the polarizing plate is optically provided on the surface of the surface protective film opposite to the antireflection film with respect to the polarizer. An optical compensation film having an optical compensation layer comprising at least one anisotropic layer, wherein the optical anisotropic layer is a birefringent layer comprising a compound having a discotic structural unit, and the discotic The disk surface of the structural unit is inclined with respect to the surface protective film surface, and the angle formed by the disk surface of the discotic structural unit and the surface protective film surface changes in the depth direction of the optically anisotropic layer. It is preferable.
[0090]
The antireflection film of the present invention, when used as one side of a polarizer surface protective film, is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optical It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device of a mode such as a curry compensate bend cell (OCB). When used in a transmissive or transflective liquid crystal display device, a commercially available brightness enhancement film (a polarized light separation film having a polarization selective layer, such as D-BEF (trade name) manufactured by Sumitomo 3M Co., Ltd.), etc. By using in combination, a display device with higher visibility can be obtained. In addition, when a front plate such as an acrylic plate is arranged over the entire surface of the liquid crystal cell in a transmissive, reflective, and transflective liquid crystal display device, not only the polarizing plate on the liquid crystal cell surface side, Adhering to the inner side and / or the outer side of the front plate via an adhesive or the like and reducing reflection at the interface are preferable. Further, by combining with a λ / 4 plate, it can be used as a reflective or transflective LCD or a surface protection plate for an organic EL display. In addition, the antireflection layer of the present invention is formed on a transparent support such as PET or PEN, and the surface protection plate of a PDA, a cellular phone, a touch panel, a plasma display panel (PDP), or a cathode ray tube display (CRT). It can be applied to various image display devices.
[0091]
【Example】
The present invention will be described in more detail based on examples, but the present invention is not limited thereto.
(Preparation of coating liquid A for hard coat layer)
306 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was dissolved in a mixed solvent of 16 parts by mass of methyl ethyl ketone and 220 parts by mass of cyclohexanone. After adding 7.5 parts by mass of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) to the resulting solution and stirring until dissolved, 450 parts by mass of MEK-ST (average particle size of 10 to 20 nm) SiO with a solid content of 30% by mass₂A sol methyl ethyl ketone dispersion (trade name, manufactured by Nissan Chemical Co., Ltd.) was added and stirred to obtain a mixture, and a polypropylene filter (PPE-03 (trade name, manufactured by Fuji Photo Film Co., Ltd.) having a pore size of 0.4 μm was obtained. )) To prepare a hard coat layer coating solution A.
[0092]
(Preparation of coating liquid B for hard coat layer)
Forward scattering property-imparting particles (trade name: SX) made of crosslinked polystyrene having an average particle size of 1.3 μm in 1000 parts by mass of the coating liquid A for hard coat layer (solvent-dried, refractive index after UV curing: 1.51). -130H, refractive index: 1.61, 150 parts by mass manufactured by Soken Chemical Co., Ltd. were added, and the mixture was stirred for 10 minutes with an air disper to obtain a mixture. Profile star 0.4 μm with a pore size of 0.4 μm (product) Name, manufactured by Nippon Pole Co., Ltd.) to prepare a coating liquid B for hard coat layer imparted with forward scattering properties.
[0093]
(Preparation of coating liquid C for hard coat layer)
91 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), a zirconium oxide ultrafine particle dispersion having a particle size of about 30 nm (trade name: Desolite Z) -7 parts by mass (-7401, manufactured by JSR Corporation) was dissolved in a mixed solvent of 52 parts by mass of methyl ethyl ketone / cyclohexanone = 54/46% by mass. To the obtained solution, 10 parts by mass of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Fine Chemicals Co., Ltd.) was added and stirred to obtain a mixture, and profile star 0.4 μm (trade name) having a pore size of 0.4 μm (trade name). , Manufactured by Nippon Pole Co., Ltd.) to prepare a hard coat layer coating solution C.
[0094]
(Preparation of organosilane sol composition A)
To a reactor equipped with a stirrer and a reflux condenser, 161 parts by mass of glycidoxypropyltrimethoxysilane, 123 parts by mass of oxalic acid, and 415 parts by mass of ethanol were added and mixed. After cooling, an organosilane sol composition A was obtained.
[0095]
(Preparation of organosilane sol composition B)
  In the preparation of the organosilane sol composition A,GlycidoxypropyltrimethoxysilaneThe organosilane sol composition B was obtained in the same manner as in the preparation of the organosilane sol composition A except that was replaced with methacryloyloxypropyltrimethoxysilane.
[0096]
(Preparation of titanium dioxide dispersion)
Titanium dioxide ultrafine particles (trade name: TTO-55B, manufactured by Ishihara Techno Co., Ltd.) 30 parts by mass, dimethylaminoethyl acrylate (DMAEA, manufactured by Kojin Co., Ltd.) 1 part by mass, phosphate group-containing anionic dispersant ( Product name: KAYARAD PM-21, Nippon Kayaku Co., Ltd.) 6 parts by mass and cyclohexanone 63 parts by mass were dispersed with a sand grinder until the average particle size measured by the Coulter method was 42 nm, and the titanium dioxide dispersion Was prepared.
[0097]
(Preparation of coating liquid A for medium refractive index layer)
To 75 parts by mass of cyclohexanone and 19 parts by mass of methyl ethyl ketone, 0.11 part by mass of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) and photosensitizer (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) ) 0.04 parts by mass were dissolved. Further, 3.1 parts by mass of titanium dioxide dispersion and 2.1 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) were added and stirred at room temperature for 30 minutes. Thereafter, the mixture was filtered through a profile star 0.4 μm (trade name, manufactured by Nippon Pole Co., Ltd.) having a pore size of 0.4 μm to prepare a coating solution A for a medium refractive index layer.
[0098]
(Preparation of coating liquid B for medium refractive index layer)
750 parts by mass of cyclohexanone, 190 parts by mass of methyl ethyl ketone, 1.2 parts by mass of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) and photosensitizer (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) ) 0.4 parts by mass was dissolved. Further, 105 parts by mass of titanium dioxide dispersion and 21 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) were added and stirred for 30 minutes at room temperature. A medium refractive index layer coating solution B was prepared by filtration through a 0.4 μm profile star 0.4 μm (trade name, manufactured by Nippon Pole Co., Ltd.).
[0099]
(Preparation of coating liquid A for high refractive index layer)
54 parts by mass of cyclohexanone and 18 parts by mass of methyl ethyl ketone, 0.13 parts by mass of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) and photosensitizer (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) ) 0.04 parts by mass were dissolved. Furthermore, 26.4 parts by mass of titanium dioxide dispersion and 1.6 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) were added and stirred at room temperature for 30 minutes. Thereafter, the mixture was filtered through a profile star 0.4 μm (trade name, manufactured by Nippon Pole Co., Ltd.) having a pore diameter of 0.4 μm to prepare a coating solution A for a high refractive index layer.
[0100]
(Preparation of coating liquid B for high refractive index layer)
52 parts by mass of cyclohexanone and 18 parts by mass of methyl ethyl ketone, 0.13 parts by mass of photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Geigy) and photosensitizer (trade name: Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) ) 0.04 parts by mass were dissolved. Furthermore, 26.4 parts by mass of titanium dioxide dispersion, 1.6 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) and organosilane sol composition A2.33 After adding part by mass and stirring for 30 minutes at room temperature, the mixture is filtered through a profile star 0.4 μm (trade name, manufactured by Nippon Pole Co., Ltd.) having a pore diameter of 0.4 μm to prepare a coating solution B for a high refractive index layer. did.
[0101]
(Preparation of coating solution A for low refractive index layer)
A 6 mass% methyl ethyl ketone solution (trade name: JN-7228, manufactured by JSR Corporation) of a thermally crosslinkable fluorine-containing resin having a refractive index of 1.42 is substituted with a solvent to obtain 85 mass% of methyl isobutyl ketone, 2- A polymer solution containing 10% by mass of solid content in a mixed solvent composed of 15% by mass of butanol was obtained. To 70 parts by mass of this polymer solution, MEK-ST (SiO 2 having an average particle size of 10 to 20 nm and a solid content concentration of 30% by mass was added.₂After adding sol methyl ethyl ketone dispersion, manufactured by Nissan Chemical Co., Ltd., trade name) 10 parts by weight, organosilane sol composition A 2.17 parts by weight, methyl isobutyl ketone 42 parts by weight and cyclohexanone 28 parts by weight The solution was filtered through a profile star 0.4 μm (trade name, manufactured by Nippon Pole Co., Ltd.) having a pore diameter of 0.4 μm to prepare a coating solution A for a low refractive index layer.
[0102]
(Preparation of coating solution B for low refractive index layer)
A coating solution B for low refractive index layer was prepared in the same manner as coating solution A for low refractive index layer, except that 2.17 parts by mass of organosilane sol composition A was replaced with 2.17 parts by mass of organosilane sol composition B. did.
[0103]
(Preparation of coating solution C for low refractive index layer)
A coating solution C for low refractive index layer was prepared in the same manner as coating solution A for low refractive index layer, except that 2.17 parts by mass of organosilane sol composition A was not added.
[0104]
[Example 1]
(Preparation of antireflection film)
Using a gravure coater, apply the above-mentioned coating liquid A for hard coat layer to a triacetyl cellulose film (TAC-TD80U, trade name, manufactured by Fuji Photo Film Co., Ltd., refractive index: 1.47) with a thickness of 80 μm. It was applied and dried at 100 ° C. for 2 minutes. Next, the coating layer was cured by irradiating with ultraviolet rays to form a hard coat layer (refractive index: 1.51, film thickness: 6 μm).
Subsequently, the above-described coating liquid A for the medium refractive index layer was applied using a gravure coater, dried at 100 ° C., then irradiated with ultraviolet rays to cure the coating layer, and the medium refractive index layer (refractive index: 1.. 63, film thickness: 67 nm).
On the medium refractive index layer, the above-described coating liquid A for high refractive index layer is applied using a gravure coater, dried at 100 ° C., then irradiated with ultraviolet rays to cure the coating layer, and the high refractive index layer ( (Refractive index: 1.90, film thickness: 107 nm).
Furthermore, on the high refractive index layer, the above coating solution for the low refractive index layer was applied using a gravure coater, dried at 120 ° C. for 1 minute, then irradiated with ultraviolet rays, and further applied at 120 ° C. for 8 minutes. Was thermally cured to provide a low refractive index layer A (refractive index: 1.43, film thickness: 86 nm). In this way, an antireflection film was produced.
In addition, the coating, drying and curing of the medium refractive index layer, the coating, drying and curing of the high refractive index layer, and the coating, drying and curing of the low refractive index layer are carried out in three coating stations, drying, It was carried out continuously in a single coating process on a coating machine having a set of curing zones.
[0105]
[Comparative Example 1]
By means of physical vapor deposition, a substantially middle refractive index layer consisting of two layers of titanium oxide (refractive index: 2.39) 25 nm and silicon oxide (refractive index 1.47) 25 nm is sequentially formed on the hard coat of Example 1 and oxidized. A high refractive index layer made of titanium 46 nm and a low refractive index layer made of silicon oxide 97 nm were formed to produce an antireflection film.
FIG. 2 shows the reflectance spectra of the antireflection films of Example 1 and Comparative Example 1 of the present invention at wavelengths from 380 nm to 780 nm. As apparent from FIG. 2 and Table 3, in Example 1, the increase in the long wavelength side and the short wavelength side of the reflection spectrum is reduced compared to Comparative Example 1, and the color of the reflected light is also reduced. I understood it.
[0106]
[Example 2]
The antireflective film produced in Example 1 was immersed in a 2.0 normal, 55 ° C. NaOH aqueous solution for 2 minutes to saponify the triacetyl cellulose surface on the back side of the film, and a triacetyl cellulose film having a thickness of 80 μm. (TAC-TD80U, trade name, manufactured by Fuji Photo Film Co., Ltd.) A film prepared by saponifying polyvinyl alcohol with iodine and adhering and protecting both sides of a polarizer produced by stretching and polarizing A plate was made. A liquid crystal display device of a notebook personal computer equipped with a transmissive TN liquid crystal display device (Sumitomo 3M Co., Ltd., which is a polarization separation film having a polarization selection layer) so that the anti-reflection film side is the outermost surface. When the polarizing plate on the viewing side of D-BEF (trade name) manufactured by the manufacturer is replaced between the backlight and the liquid crystal cell), there is very little reflection of the background and a display device with very high display quality is obtained. Obtained.
[0107]
[Example 3]
The saponification treatment of Example 2 was performed except that a 1.0 N KOH aqueous solution was applied to the back surface of the antireflection film with a # 3 bar, treated at a film surface temperature of 60 ° C. for 10 seconds, washed with water and dried. Was affixed to a liquid crystal display device in the same manner as in Example 2, and a display device with high display quality similar to that in Example 2 was obtained.
[0108]
[Example 4]
In the protective film on the liquid crystal cell side of the polarizing plate on the viewing side and the protective film on the liquid crystal cell side of the polarizing plate on the backlight side of the transmission type TN liquid crystal cell to which the antireflection film of Example 3 was attached, the discotic structural unit The disc surface is inclined with respect to the transparent support surface, and the angle formed by the disc surface of the discotic structural unit and the transparent support surface has an optical compensation layer that varies in the depth direction of the optical anisotropic layer. When using a viewing angle widening film (wide view film SA-12B, trade name, manufactured by Fuji Photo Film Co., Ltd.), it has excellent contrast in a bright room and very wide viewing angles in the vertical and horizontal directions. A liquid crystal display device having excellent properties and high display quality was obtained.
[0109]
[Examples 5 to 7 and Comparative Example 2]
The same procedure as in Example 1 was performed except that the coating liquid shown in Table 1 below was used instead of the coating liquid for the hard coat, medium refractive index layer, high refractive index layer, and low refractive index layer of Example 1. The antireflection films of Examples 5 to 7 and Comparative Example 2 were produced.
[0110]
[Table 1]

[0111]
The scratch resistance of the antireflection films of Examples 1, 5 to 7 and Comparative Example 2 was evaluated by the method described below. The results are shown in Table 2 below.
[0112]
[Abrasion Resistance Evaluation Method for Antireflection Film]
(1) Steel wool rubbing test
As an index of scratch resistance, the antireflection film was conditioned for 2 hours at a temperature of 25 ° C. and a humidity of 60% RH, then rubbed 10 times with a load of 200 g using steel steel of # 0000, and then the antireflection film. The back surface of was coated with black ink, and the antireflection film side was visually observed under a fluorescent lamp, and the following four-step evaluation was performed.
Visually, no scratches can be seen: ◎
Visible scratches are hardly visible by visual inspection.
Visible scratches are visible but not noticeable: △
Visible scratches are noticeable visually: ×
[0113]
(2) Wet rubbing test
As another index of scratch resistance, the antireflection film is conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then the pure cotton is sufficiently contained in the tip of a commercially available cotton swab to a load of 1 kg. Then, the back surface of the antireflection film was solid-coated with black ink, and the antireflection film side was visually observed under a fluorescent lamp.
Visually, no scratches can be seen: ◎
Visible scratches are hardly visible by visual inspection.
Visible scratches are visible but not noticeable: △
Visible scratches are noticeable visually: ×
[0114]
[Table 2]

[0115]
As is clear from Table 2, Comparative Example 2 is inferior to Examples 1 and 5 to 7 in terms of adhesion between layers because no hydrolyzate or partial condensate of the organosilane compound was added. It turned out that it is inferior to scratch resistance compared with 5-7. On the other hand, it was found that the antireflection films of Examples 1 and 5 to 7 were excellent in scratch resistance because the adhesion between layers and the hardness of the self-layer were high in at least one of the plurality of optical thin films. .
[0116]
[Example 8]
An antireflection film having a forward scattering function was produced in the same manner as in Example 1 except that the hard coat layer coating solution B was used instead of the hard coat coating solution A in Example 1, and the same as in Example 4. Then, this forward scattering antireflection film is disposed on the outermost surface side, and a polarizing plate having a viewing angle widening film wide view film (WV-12A, trade name, manufactured by Fuji Photo Film Co., Ltd.) is disposed on the liquid crystal cell side. A transmissive TN liquid crystal display device was produced.
In the liquid crystal display device thus manufactured, the limit angle at which gradation inversion occurs when the viewing angle is tilted downward is improved from 40 degrees to 60 degrees as compared with Example 4, and the visibility and display quality are improved. It was very good.
[0117]
[Example 9]
The polarizing plate having the antireflection layer of Example 3 is disposed on the outermost surface, and the antireflection film prepared in Example 1 is bonded to both the inner and outer surfaces of the acrylic front plate via an adhesive, and the front plate is attached. When a mobile phone including a transflective liquid crystal display device arranged on the outermost surface was manufactured, a display device having high visibility and no inferiority to an antireflection-treated liquid crystal display device without a front plate was obtained.
[0118]
[Comparative Examples 3 to 5]
What stuck the antireflection film produced in Example 1 on both the inside and outside of the acrylic front plate used in Example 9 and stuck the antireflection film of Example 1 only on the inside of the front plate A mobile phone equipped with a transflective liquid crystal display device was produced in the same manner as in Example 9, except that nothing was bonded and that the front plate and the liquid crystal cell were not antireflective. However, in all cases, the visibility deteriorates with the decrease in the number of antireflection films, and in particular, those with no antireflection were completely unreadable in the characters reflected in fluorescent lights and the like.
[0119]
[Example 10]
When the antireflection film produced in Example 1 was bonded to the glass plate on the surface of the organic EL display device via an adhesive, reflection on the glass surface was suppressed, and a display device with high visibility was obtained.
[0120]
[Example 11]
When a λ / 4 plate was bonded to the opposite side of the polarizing plate with the antireflection film of the single-sided antireflection film prepared in Example 3 and attached to the glass plate on the surface of the organic EL display device, the surface The reflection and the reflection from the inside of the surface glass were cut, and a display with extremely high visibility was obtained.
[0121]
[Example 12]
A hard coat coating solution C is applied to the undercoat surface of a polyethylene terephthalate film (trade name: Cosmo Shine A4100, manufactured by Teijin Ltd., refractive index: 1.65) having a single-side undercoat layer and a thickness of 188 μm as in Example 1. Then, coating, drying of the solvent, and ultraviolet curing were performed to form a hard coat layer (refractive index: 1.61, film thickness: 8 μm).
Subsequently, the above-described coating liquid B for medium refractive index layer was applied using a gravure coater, dried at 100 ° C., then irradiated with ultraviolet rays to cure the coated layer, and the medium refractive index layer (refractive index: 1.. 70, film thickness: 70 nm).
On the medium refractive index layer, the above high refractive index layer coating solution is applied using a gravure coater, dried at 100 ° C., then irradiated with ultraviolet rays to cure the coated layer, and the high refractive index layer (refractive (Rate: 1.90, film thickness: 120 nm).
Further, the coating solution A for low refractive index layer is applied on the high refractive index layer using a gravure coater, and the coating layer is cured at 120 ° C. for 8 minutes to obtain a low refractive index layer (refractive index: 1.. 43, film thickness: 90 nm). In addition, from the middle refractive index layer to the low refractive index layer, in the same manner as in Example 1, one coating process is performed by a coating machine having a set of three coating stations, drying and curing zones in one coating machine. Conducted continuously in.
In this way, an antireflection film was produced.
When the produced antireflection film was affixed to the outermost surface of the flat CRT and PDP, a display device was obtained that simultaneously satisfied low reflection, reduced reflected light color, and high film hardness.
[0122]
(Evaluation of antireflection film)
For the films obtained in Examples 1 and 12 and Comparative Example 1, the following items were evaluated. The results are shown in Table 3 below.
(1) Specular reflectance and color
A spectrophotometer V-550 (trade name, manufactured by JASCO Corporation) is equipped with an adapter ARV-474 (trade name), and in the wavelength region of 380 to 780 nm, the output angle is -5 degrees at an incident angle of 5 °. The specular reflectance was measured, an average reflectance of 450 to 650 nm was calculated, and antireflection properties were evaluated.
Further, from the measured reflection spectrum, the CIE standard light source D₆₅CIE1976L representing the color of regular reflected light with respect to 5 degree incident light^*a^*b^*L of color space^*Value, a^*Value, b^*The value was calculated and the color of reflected light was evaluated.
(2) Pencil hardness evaluation
The pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. After conditioning the antireflection film at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, it was evaluated using the 2H-5H test pencil specified in JIS S6006 at a load of 500 g as follows. The highest hardness that results in OK was taken as the evaluation value.
In evaluation of n = 5, there is no scratch to one scratch: OK
In evaluation of n = 5, 3 or more scratches: NG
(3) Contact angle measurement
As an index of surface contamination resistance, the optical material was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then the contact angle of pure water was measured to obtain an index of fingerprint adhesion.
[0123]
(4) Dynamic friction coefficient measurement
The dynamic friction coefficient was evaluated as an index of surface slipperiness. For the dynamic friction coefficient, the sample was conditioned at 25 ° C. and 60% relative humidity for 2 hours, and then measured with a HEIDON-14 (trade name) dynamic friction measuring machine at a 5 mmφ stainless steel ball, a load of 100 g, and a speed of 60 cm / min. It was.
(5) Vertical peel charge measurement
The vertical peel charge amount was measured by the method described in the text.
(6) Surface resistance value
The surface resistance value was measured by the circular electrode method.
[0124]
[Table 3]

[0125]
As is clear from Table 3, the antireflection films of Example 1 and Example 12 are compatible with low reflectance and color reduction, have not only very favorable reflection characteristics, but also have low dynamic friction, so that they are scratch resistant. Since the contact angle of pure water is high and the contact angle of pure water is high, the water and oil repellency is excellent, so that the antifouling property is excellent, the pencil hardness is high, and it is difficult to be damaged. On the other hand, the antireflection film of Comparative Example 1 was inferior in display quality because the reflected light was strongly colored reddish purple. Further, since the dynamic friction was high, the scratch resistance was poor, the contact angle of pure water was low, and the antifouling property was poor.
Further, the CIE standard light source D in the wavelength region from 380 nm to 780 nm in any two places 10 cm apart in the TD direction and the MD direction.₆₅The color unevenness of the regular reflected light with respect to the incident light of 5 degrees is CIE1976L^*a^*b^*ΔE of color space^* _abSince the value falls within the range of 0 to 1.5, the uniformity of the color of the reflected light at different locations is high. Also, the surface resistance values are all 1 × 10¹²Ω / □ or more but vertical peeling charge is + 120pC (picocoulomb) / cm²It was excellent in dust resistance.
[0126]
[Example 13]
A polarizing plate was produced in the same manner as in Example 2 except that the polarizer produced in the following method was used as the polarizer in Example 2. The antireflection performance was the same as in Example 1, but the absorption axis direction of the obtained polarizer was inclined by 45 ° with respect to the longitudinal direction, and punching dust generated when punching the polarizing plate into each size was found. Diminished.
(Production of polarizer)
The PVA film was immersed in an aqueous solution of 5.0 g / L of iodine and 10.0 g / L of potassium iodide at 25 ° C. for 90 seconds, and further immersed in an aqueous solution of boric acid 10 g / L at 25 ° C. for 60 seconds. Fig. Of Publication No. 2002-8840A1. It was introduced into a tenter stretching machine having the form 2 and once stretched to 7.0 times and then shrunk to 5.3 times. Thereafter, the width was kept constant, dried at 70 ° C. and then detached from the tenter. The difference in transport speed between the left and right tenter clips was less than 0.05%, and the angle between the center line of the introduced film and the center line of the film sent to the next process was 0 °. Here, FIG. In FIG. 2, | L1-L2 | and W were both 0.7 m. Wrinkles and film deformation at the tenter exit were not observed. The transmittance of this polarizer at 550 nm was 43.3%, and the degree of polarization was 99.98%.
[0127]
【The invention's effect】
The antireflection film of the present invention has improved scratch resistance while having sufficient antireflection performance and antifouling properties.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a specific example of an antireflection film of the present invention.
FIG. 2 is a reflectance spectrum of the antireflection films of Example 1 and Comparative Example 1 of the present invention at wavelengths from 380 nm to 780 nm.
[Explanation of symbols]
1 Transparent support
2 Hard coat layer
3 Medium refractive index layer
4 High refractive index layer
5 Low refractive index layer

Claims (13)

An antireflection film having a low refractive index layer mainly composed of a fluorine-containing resin having a refractive index lower than that of the support and a high refractive index layer adjacent thereto on the transparent support,
The fluorine-containing resin is a fluorine-containing resin that is cured by heat or ionizing radiation, and is a fluorine-containing copolymer having a fluorine-containing monomer and a monomer for imparting a crosslinkable group as structural units,
The low refractive index layer and the high refractive index layer contain a hydrolyzate of organosilane represented by the following general formula (1) and / or a partial condensate thereof , and metal oxide fine particles ,
The high refractive index layer contains a hydrolyzate of organosilane represented by the following general formula (1) and / or a partial condensate thereof, fine metal oxide particles, a heat or ionizing radiation curable monomer, and an initiator. An antireflective film, which is formed by applying a coating composition to be applied onto the transparent support and curing it with heat and / or ionizing radiation .
General formula (1)
_{^{(R 10) m -Si (X}} ) 4-m (1)
(In the formula, R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. X represents a hydroxyl group or a hydrolyzable group. M represents an integer of 1 to 3. ) In the low refractive index layer, the content of the hydrolyzate of organosilane represented by the general formula (1) and / or the partial condensate thereof is 0.1 to 50% by mass of the total solid content of the containing layer. The antireflection film according to claim 1, wherein the antireflection film is provided. In the high refractive index layer, the content of the hydrolyzate of organosilane represented by the general formula (1) and / or the partial condensate thereof is 0.001 to 50% by mass of the total solid content of the containing layer. The antireflection film according to claim 1, wherein the antireflection film is provided. The content of the hydrolyzate of organosilane represented by the general formula (1) with respect to the fluororesin and / or the partial condensate thereof in the low refractive index layer is 5 to 100% by mass. The antireflection film according to any one of claims 1 to 3.   At least one of the low refractive index layer and / or a layer adjacent to the low refractive index layer contains a hydrolyzate of organosilane represented by the general formula (1) and / or a partial condensate thereof. 5. The antireflection film according to claim 1, comprising an organosilane compound represented by the general formula (1), a hydrolyzate thereof, or a partial condensate thereof.   6. The antireflection film according to claim 5, wherein the layer containing the organosilane compound represented by the general formula (1), a hydrolyzate thereof or a partial condensate thereof contains metal oxide fine particles. In the antireflection film, the average value of the specular reflectance at 5 ° incidence in the wavelength region from 450 nm to 650 nm is 0.5% or less, and the CIE standard light source D ₆₅ of 5 in the region from 380 nm to 780 nm is used. The color of the specularly reflected light with respect to the incident light is set so that the a ^* and b ^* values of the CIE1976L ^* a ^* b ^* color space are −7 ≦ a ^* ≦ 7 and −10 ≦ b ^* ≦ 10, respectively. The antireflection film according to claim 1, wherein the antireflection film is formed.   Each layer on the transparent support is formed by coating a coating composition containing a film-forming solute and at least one solvent, drying the solvent, curing by heat and / or ionizing radiation. The antireflection film according to claim 1, wherein the film is an antireflection film.   Between the low refractive index layer and the transparent support, a high refractive index layer having a higher refractive index than the support in order from the low refractive index layer side, an intermediate refractive index between the support and the high refractive index layer. The antireflective film according to any one of claims 1 to 8, wherein three layers having substantially different refractive indexes of the medium refractive index layer are formed.   It is a polarizing plate in which two surface protective films are bonded to the front and back surfaces of a polarizer, and the antireflection film according to any one of claims 1 to 9 is used as at least one side surface protective film. A characteristic polarizing plate.   An optical compensation film having an optical compensation layer comprising at least one optically anisotropic layer on a surface of the surface protective film opposite to the antireflection film with respect to the polarizer; The discotic structural unit is a birefringent layer comprising a compound having a discotic structural unit, the disc surface of the discotic structural unit is inclined with respect to the surface protective film surface, and the disc surface of the discotic structural unit The polarizing plate according to claim 10, wherein an angle formed by the surface protective film surface changes in the depth direction of the optically anisotropic layer.   An image display device comprising at least one antireflection film according to any one of claims 1 to 9 or a polarizing plate according to claim 10 or 11.   The constituent layer on the support of the antireflection film according to any one of claims 1 to 9 is a process of feeding the support film once, forming each optical thin film, and winding the film. A method for producing an antireflection film, characterized in that the antireflection film is formed.

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