JP3849232B2 - Optical thin film, antireflection article and antireflection method - Google Patents

Description

また、前記の架橋性フッ素含有化合物（Ｃ）の１００重量部に対し、多官能シラン化合物（Ｄ）を０〜１００重量部含有している光学薄膜が好適である。多官能シラン化合物（Ｄ）がエポキシ基を有する場合には、架橋性フッ素含有化合物（Ｃ）の１００重量部に対し、多官能エポキシ樹脂（Ｅ）を０〜１００重量部含有させるとよい。前記した光学薄膜は屈折率が１．４６を超えず、膜厚さが３０〜７００ｎｍのものが好ましい。
【００１０】
さらに本発明は、基材表面に前記のいずれかの光学薄膜を形成したことを特徴とする反射防止性物品を提供する。基材表面と光学薄膜との中間に、有機および／または無機系バインダーと金属化合物の微粒子とからなり、かつ屈折率が基材の屈折率の±０．０２以内のハードコート層を形成することができる。さらにハードコート層と光学薄膜との中間に、光学薄膜およびハードコート層の屈折率よりも高い屈折率を有する高屈折率膜を積層するとよい。ハードコート層は主に表面の耐擦傷性を強化し、高屈折率膜は反射防止性を高める効果がある。
【００１１】
そして本発明は、１分子内に少なくとも１個のパーフルオロ基および複数のＯＨ基
を持つ化合物（Ａ）と、１分子内に１個のイソシアネート基およびケイ素に結合する
複数の加水分解性基を持つシラン化合物（Ｂ）とをウレタン化反応させて架橋性フッ
素含有化合物（Ｃ）を製造し、得られた架橋性フッ素含有化合物（Ｃ）を含有せしめ
た組成物を調合し、基材表面または基材被膜表面にコーティングし、硬化させること
を特徴とする反射防止方法を提供する。
【００１２】
【発明の実施の形態】
本発明の光学薄膜、反射防止性物品および反射防止方法について、実施形態をあげて具体的に説明する。
まず、硬化により本発明の光学薄膜を形成する架橋性フッ素含有化合物（Ｃ）について説明する。フッ素含有化合物（Ｃ）を形成するのに用いる、１分子内にパーフルオロ基と複数のＯＨ基とを持つ化合物（Ａ）として具体的には、次の一般式（２）〜（５）で示されるものが挙げられる。
【００１３】
【化３】

なかでも、化４の一般式（６）で示される化合物は、低屈折率の光学被膜を得やすく、かつ製造が容易である。
【００１４】
【化４】

一般式（６）で示される化合物のうち、特に本発明で好適に使用されるのは、低屈折率が得られ、且つ最も製造の容易なｎ＝４〜１２の整数で示される化合物である。
【００１５】
次に、本発明で用いられる１分子内に１個のイソシアネート基とケイ素に結合する
複数の加水分解基とを持つシラン化合物（Ｂ）として化５に一般式（７）で示される
化合物があげられる。
【００１６】
【化５】

一般式（７）で示される化合物のうち、本発明で最も好適に使用されるのは、架橋性、反応生成物の無害性及び製造の容易性から、化６に一般式（８）〜（１１）で示される化合物をあげることができる。
【００１７】
【化６】

さて、本発明の光学薄膜には、硬度、上下層との密着性、屈折率の調整などの性能向上を目的に多官能シラン化合物（Ｄ）を含有させることができる。量的には架橋性フッ素含有化合物（Ｃ）の１００重量部にたいし、多官能シラン化合物（Ｄ）の１００重量部を、好ましくは９０重量部を超えない量である。多官能シラン化合物（Ｄ）が１００重量部を越えると、屈折率が１．４６を越え、反射防止性能を得にくくなる傾向がある。
【００１８】
多官能シラン化合物（Ｄ）としては、ジメチルジメトキシシラン、ジメチルジエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、γ−グリシドキシプロピルメチルジエトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、ビニルトリエトキシシランなどを、単独または二種以上を混合して使用することができる。
【００１９】
多官能シラン化合物（Ｄ）のうち、エポキシ基を持つものは、硬度や上下層との密着性改善を行う上で好ましく用いられる。多官能シラン化合物（Ｄ）がエポキシ基を持つ場合、架橋性フッ素含有化合物（Ｃ）の１００重量部にたいし、多官能エポキシ樹脂（Ｅ）の１００重量部を、好ましくは９０重量部を超えない量を含有させることができる。多官能エポキシ樹脂が１００重量部を越えると、屈折率が１．４６を超え、本発明の目的とする反射防止性能を得ることができない傾向がある。
【００２０】
多官能エポキシ樹脂（Ｅ）として、ビスフェノールＡ系ジグリシジルエーテル、ノボラック系ポリグリシジルエーテル、エチレングリコール系ジグリシジルエーテル、プロピレングリコール系ジグリシジルエーテル、水添ビスフェノールＡ系ジグリシジルエーテルなどを単独または２種以上を混合して使用する。
【００２１】
次に、架橋性フッ素含有化合物（Ｃ）の製造方法について説明する。化合物（Ａ）とシラン化合物（Ｂ）とのウレタン化反応は、通常、エステル系、ケトン系、エーテル系、炭化水素系などのイソシアネート基と反応する基を持たない有機溶剤中で行う。反応温度は室温ないし８０℃程度が好ましく、ジラウリン酸ジ−ｎ−ブチル錫などのウレタン化触媒を加えてもよい。ウレタン化反応の後、溶剤を除去して架橋性フッ素含有化合物（Ｃ）を取り出し、塗液を調整して光学薄膜の形成に用いることもできるが、好ましくは、塗液を調整する過程でウレタン化反応を一体的に行う。後者の方法においては、有機溶剤の全部または少なくとも一部が塗液の溶剤としても使われることになる。
【００２２】
本発明の光学薄膜は、以上に説明した各化学物質をアルコール系、エステル系、ケトン系、エーテル系、炭化水素系などの溶剤に溶解した塗液を基材に塗布して形成される。
塗布工程の前処理として、通常、塗液に含まれているシラン系加水分解性基を加水分解する。加水分解は、一般的に当量の水を加えて撹拌して行うが、触媒として微量の酸、とくに塩酸の併用が効果的である。
【００２３】
前記の塗液には硬化剤を加える。硬化剤は、ポットライフの長いアルミニウム、鉄、銅などの金属キレート化合物、一般的にはアルミニウムアセチルアセトネート、アルミニウムビスエチルアセトアセテートモノアセチルアセトネート、アルミニウム−ジ−ｎ−ブトキシドモノエチルアセトアセテート、アルミニウムージ−ｉｓｏ−プロポキシドモノメチルアセトアセテートなどを用いる。硬化剤の添加量は、硬化物組成全体の０．１〜２０重量部、好ましくは０．２〜１０重量部である。
【００２４】
また、この他、使用目的に応じて必要な添加剤、たとえば、均一コーティング性や密着性を改良するためにレベリング剤やカップリング剤を添加することも行われる。レベリング剤やカップリング剤の添加量は硬化物組成全体の０．０５〜５重量部、好ましくは０．１〜２重量部である。
塗布方法としては、基材に均一に塗布できる方法であれば特に限定されず、スピンコート、ディップコート、ダイコート、スプレーコート、バーコーターコート、ロールコート、カーテンフローコートなどがあげられる。
【００２５】
本発明の光学薄膜となる組成物は、好ましくは、均一な厚さで基材に塗布した後、熱硬化する。本発明の薄膜を形成することのできる基材に制限はない。なかでも、通常のガラスをはじめとして厚さ１ｍｍ以下の薄板ガラス、ポリカーボネートやＰＭＭＡ（ポリメチルメタクリレート）などのプラスチック基材、ポリエチレンテレフタレートフィルムなどのフィルム類の透明性基材の光反射防止に効果的に利用することができる。ほかにも撥水、撥油性能などの優れた特性を具備するので、それらを利用する薄膜を形成してもよい。基材の形状にも特別の制限はない。
【００２６】
基材には、たとえば密着性や塗布性を向上させる目的で、表面処理を施したり、中間層をもうけることができる。中間膜に高屈折率の光学薄膜を用いれば反射防止効果が高まり、また、高屈折率薄膜と本発明の光学薄膜とを交互に多数積層することにより、さらに優れた反射防止膜を得ることができる。反射防止効果を高めるのに要する高屈折率膜の屈折率は、基材と同等もしくはそれ以上が必要であり、好ましくは１．５８以上、さらに好ましくは１．６以上、より好ましくは、１．７以上である。
【００２７】
反射防止性物品に光学薄膜を形成する前に行う好ましい処理方法を、実施形態例をあげて説明する。たとえば、ポリカーボネートやＰＭＭＡの樹脂基材の表面に硬度付与と干渉縞をなくする目的で、基材との屈折率差が±０．０２以内、厚さ２〜５μｍ程度のハードコート層を形成しておく。ハードコート層は、有機系または無機系のバインダーに、必要に応じてＳｉ、Ｓｂ、Ｃｅ、Ｔｉ、Ｓｎなどの金属酸化物微粒子、すなわち一般的には可視光線の波長よりも小さい粒子径の微粒子を添加した塗膜を用いる。有機バインダーとしては、エポキシ樹脂硬化物やラジカル架橋重合した樹脂などが、無機系バインダーとしては、シラン系化合物の加水分解硬化物などがあるが、特に制限はない。硬化には一般的に熱硬化法よりも光硬化法を用いる方が硬化速度が速く好ましい。
【００２８】
高い反射防止性を得るために、ハードコート層上に前記の高屈折率薄膜を積層することができる。高屈折率膜の厚さは９０〜４００ｎｍ、より好ましくは１１０〜１８０ｎｍにする。一般的にはＳｂ、Ｃｅ、Ｔｉ、Ｓｎなどの金属酸化物を含み、ペンタエリスリトールトリアクリレート、２−ヒドロキシ−３−フェノキシアクリレートのような（メタ）アクリレート類、シラン類、エポキシ樹脂類などをバインダーとする層として形成する。導電性金属酸化物を用いれば、帯電防止性を付与する効果がある。硬化には一般的に熱硬化法よりも光硬化法を用いる方が硬化速度が速く好ましい。
【００２９】
光学薄膜の膜の厚さはλ／４ｎ（λ：薄膜内での光の波長、ｎ：薄膜の屈折率）の奇数倍が好ましい。光の波長に幅のある場合、λは光の中心波長を基準にする。本発明で対象光は、通常、可視光なので、中心波長は人間が敏感に感じる５００〜５５０ｎｍに設定するのが好ましい。
【００３０】
本発明の光学薄膜の膜厚は、薄膜の屈折率にもよるが、好ましくは、３０〜７００ｎｍ、より好ましくは、４０〜１２０ｎｍである。光学薄膜の膜厚が３０ｎｍ未満の場合は、可視光における光干渉作用による反射率の低減が不十分になることがある。また、膜厚が７００ｎｍを超えると、反射率がほぼ空気と薄膜界面の反射のみに依存するようになるので、可視光の光干渉による反射率の低減が不十分になる傾向がある。
【００３１】
【実施例】
以下に本発明を実施例をあげて具体的に説明する。なお、以下の実施例および参考例において用いた評価手段および測定手段は次の通りである。
ａ．膜の厚さ：エリプソメータによる測定値。
ｂ．片面反射率：測定面の裏面をサンドペーパで粗面化した後、油性インキで黒塗りし、分光光度計を用い、５４０ｎｍにおける測定面の反射率を測定した。
【００３２】
ｃ．干渉縞：蛍光灯スタンドの２０ｃｍ下にサンプルを静置し、肉眼観察により評価した。
ｄ．耐擦傷性：消しゴム（Ｎｏ．５０（ライオン（株）製）を接触面積約０．５ｃｍ² 、荷重１ｋｇで反射面上を２０回往復させた後、肉眼判定し、擦過痕が認められないものを合格判定した。
【００３３】
実施例１
表１に記載の組成液を調整し、４０℃、８時間反応させて、架橋性フッ素含有化合物を含む溶液Ｒを得た。
【００３４】
【表１】

溶液Ｒを用いて次の組成の加水分解液を調合し塗料Ａとした。
【００３５】
溶液Ｒ １０ 重量部
イソプロパノール ７０ 重量部
１／１０Ｎ塩酸 ０．５重量部
厚さ２ｍｍのポリカーボネート板の表面に塗料Ａをスピンコートし、８０℃のオーブンで２０分間、加熱処理した。続いて１３０℃のオーブンで２時間、熱硬化処理し、厚さ９５ｎｍの硬化膜を得た。得られた膜の屈折率を測定したところｎｄ＝１．４２であり、片面反射率は１．３％であった。
【００３６】
参考例１
コーティング前のポリカーボネート板の片面反射率の測定結果は５．２％であった。
【００３７】
実施例２
表２に記載の組成液を調整し、４０℃、８時間反応させて、架橋性フッ素含有化合物を含む溶液Ｓを得た。
【００３８】
【表２】

溶液Ｓを用いて次の組成の加水分解液を調合し塗料Ｂとした。
【００３９】
溶液Ｓ １０ 重量部
イソプロパノール ６０ 重量部
１／１０Ｎ塩酸 ０．３重量部
実施例１と同様にして硬化膜を得た。得られた膜の屈折率はｎｄ＝１．４３、片面反射率は１．４％であった。
【００４０】
実施例３
架橋性フッ素含有化合物を含む次の組成の加水分解液を調合し、塗料Ｃとした。
化７の（１２）式で示される架橋性フッ素含有化合物 １０ 重量部
γ−グリシドキシプロピルトリメトキシシラン ７ 重量部
アルミニウムアセチルアセトナート ０．２重量部
イソプロパノール ８３ 重量部
１／１０Ｎ塩酸 ２．７重量部
実施例１と同様にして硬化膜を得た。得られた膜の屈折率はｎｄ＝１．４６、片面反射率は１．８％であった。
【００４１】
【化７】

実施例４
架橋性フッ素含有化合物を含む次の組成の加水分解液を塗料Ｄとした。
【００４２】

実施例１と同様にして硬化膜を得た。得られた膜の屈折率はｎｄ＝１．４５、片面反射率は１．７％であった。
【００４３】
【化８】

実施例５
架橋性フッ素含有化合物を含む次の組成の加水分解液を塗料Ｅとした。
【００４４】
化９の（１４）式で示される架橋性フッ素含有化合物 １０ 重量部
γ−グリシドキシプロピルメチルジエトキシシラン ２ 重量部
エピコート８２７ ２ 重量部
アルミニウムアセチルアセトナート ０．１重量部
イソプロパノール ８６ 重量部
１／１０Ｎ塩酸 １．４重量部
実施例１と同様にして硬化膜を得た。得られた膜の屈折率はｎｄ＝１．４６、５４０ｎｍにおける片面反射率は１．８％であった。
【００４５】
【化９】

実施例６〜１０
厚さ２ｍｍのポリカーボネート板（屈折率１．５９）の表面に、平均粒子径（ＢＥＴ法）が２０ｎｍの酸化アンチモン超微粒子、ペンタエリスリトールトリアクリレート、２−ヒドロキシ−３−フェノキシアクリレートを主成分とし、光硬化した厚さ３μｍ、屈折率１．５９、のハードコート層を形成させた。実施例１と同様にして、塗料Ａ、Ｂ、Ｃ、Ｄ、Ｅを上記ハードコート層上に塗布し、表３の結果を得た。いずれも優れた耐擦傷性を示した。
【００４６】
実施例１１〜１５
実施例６〜１０で得られたポリカーボネート板のハードコート層上に、平均粒子径（ＢＥＴ法）が５０ｎｍのドープ酸化スズ超微粒子、ペンタエリスリトールトリアクリレート、２−ヒドロキシ−３−フェノキシアクリレートを主成分とする、厚さ１５０ｎｍ、屈折率ｎｄ＝１．７０、表面抵抗値２×１０⁹ Ω／□の導電性高屈折率層を光硬化により形成させた。さらに、実施例１と同様にして、高屈折率層上に塗料Ａ、Ｂ、Ｃ、Ｄ、Ｅを塗布し、硬化して表４の結果を得た。いずれも高い耐擦傷性を示した。
【００４７】
【表３】

【００４８】
【表４】

【００４９】
【発明の効果】
本発明の光学薄膜は、低屈折率で高架橋性フッ素含有化合物を含有せしめた組成物を硬化して形成されているので、可視光線の反射率が低く、高い耐擦傷性を得ることができる。また、溶液コーティングを利用できるため、生産性が高く経済的である。さらに、フッ素元素の効果による撥水・撥油効果がある。本発明により、耐擦傷性、耐久性に優れた反射防止物品を提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical thin film excellent in scratch resistance, an antireflection article, and an antireflection method, and provides an optical thin film having a low refractive index for the purpose of reducing light reflectance. The optical thin film of the present invention is suitable for preventing reflection of a cathode ray tube, a liquid crystal display device, a CRT filter, an exhibition case, a show window, a forehead, a window glass, a lens, or the like.
[0002]
In the present invention, the optical thin film refers to a thin film that causes interference at a boundary having a different refractive index when an external light beam is reflected by a substrate whose surface is covered with a transparent thin film. Further, the refractive index is a value at the D-line of the sodium emission spectrum unless otherwise specified.
[0003]
[Prior art]
Many of the conventional light antireflective articles prevent reflection of light by alternately laminating a single layer low refractive index optical thin film or a low refractive index and high refractive index optical thin film on the surface. The reflected light of the optical thin film is interference light of each reflected light on the optical thin film surface and the thin film boundary surface, and the reflectance is reduced or increased depending on the refractive index and the film thickness of the optical thin film, but the refractive index is low in principle. The lower the reflectivity, the more advantageous. The optical thin film generally forms an inorganic coating on the surface of an article (base material) using vapor deposition or sputtering. The obtained antireflection film has low reflectivity and excellent scratch resistance. However, since a vacuum apparatus or the like is used, the productivity is poor and the manufacturing cost is high. In addition, since the substrate is heated in the manufacturing process, there is a problem that the usable materials are limited.
[0004]
In order to solve the above problem, Japanese Patent Laid-Open No. 4-355401 and Japanese Patent Laid-Open No. 6-18705 disclose low refractive index reflection by dissolving a low refractive index organic substance in a solvent and coating the substrate. A solution coating method for forming a protective film is disclosed. If the solution coating method is used, it is possible to coat a fluorine-containing resin having a refractive index lower than that of the magnesium fluoride thin film having the lowest refractive index among the inorganic thin films. And solution coating is highly productive and economical.
[0005]
However, the organic thin film made of the fluorine-containing resin described in JP-A-4-355401 and JP-A-6-18705 has a low surface hardness because of the low cross-linking density of the fluorine-containing resin cured product, and has scratch resistance. There was a problem. In addition, US Pat. No. 3,310,606 discloses a cured product of perfluorodivinyl ether as a fluorine-containing resin having a high crosslinking density and a high surface hardness. However, it is insoluble in a solvent and has a high temperature and a high pressure. An optical thin film cannot be obtained because it needs to be molded below.
[0006]
Japanese Patent Application Laid-Open No. 8-239430 has water / oil repellency and scratch resistance containing 10 to 90 parts by weight of polyfunctional (meth) acrylate with respect to 100 parts by weight of fluorine-containing di (meth) acrylate. Further, a fluorine-containing curable composition is disclosed. However, this curable composition tends to have a refractive index exceeding 1.46, and it is difficult to obtain antireflection performance.
[0007]
[Problems to be solved by the invention]
The present invention provides an optical thin film that has a low refractive index that provides a low reflective film, has a high surface hardness after curing, is excellent in durability, and can be easily formed, and reflection using the optical thin film As a result of research on the problem of providing a preventive article, it has been completed.
[0008]
[Means for Solving the Problems]
The above-described problems are solved by the present invention, that is, a compound (A) having at least one perfluoro group and a plurality of OH groups in one molecule, one isocyanate group in one molecule, and a plurality bonded to silicon. An optical thin film formed by curing a composition containing a crosslinkable fluorine-containing compound (C) obtained by urethanation reaction with a silane compound (B) having a hydrolyzable group of Can be solved. As the crosslinkable fluorine-containing compound (C) preferred in the present invention, a compound represented by the general formula (1) of Chemical Formula 2 can be given.
[0009]
[Chemical 2]

Moreover, the optical thin film which contains 0-100 weight part of polyfunctional silane compounds (D) with respect to 100 weight part of said crosslinkable fluorine-containing compound (C) is suitable. When the polyfunctional silane compound (D) has an epoxy group, the polyfunctional epoxy resin (E) may be contained in an amount of 0 to 100 parts by weight with respect to 100 parts by weight of the crosslinkable fluorine-containing compound (C). The optical thin film described above preferably has a refractive index not exceeding 1.46 and a film thickness of 30 to 700 nm.
[0010]
Furthermore, the present invention provides an antireflective article characterized in that any one of the above optical thin films is formed on the surface of a substrate. Forming a hard coat layer composed of organic and / or inorganic binder and metal compound fine particles between the substrate surface and the optical thin film and having a refractive index within ± 0.02 of the refractive index of the substrate. Can do. Further, a high refractive index film having a refractive index higher than that of the optical thin film and the hard coat layer may be laminated between the hard coat layer and the optical thin film. The hard coat layer mainly enhances the scratch resistance of the surface, and the high refractive index film has the effect of improving the antireflection property.
[0011]
In the present invention, the compound (A) having at least one perfluoro group and a plurality of OH groups in one molecule, one isocyanate group and a plurality of hydrolyzable groups bonded to silicon in one molecule are provided. A silane compound (B) having a urethanization reaction is produced to produce a crosslinkable fluorine-containing compound (C), and a composition containing the resulting crosslinkable fluorine-containing compound (C) is prepared. Alternatively, the present invention provides an antireflection method characterized by coating on the surface of a substrate film and curing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The optical thin film, antireflective article and antireflection method of the present invention will be specifically described with reference to embodiments.
First, the crosslinkable fluorine-containing compound (C) that forms the optical thin film of the present invention by curing will be described. Specifically, as the compound (A) having a perfluoro group and a plurality of OH groups in one molecule used for forming the fluorine-containing compound (C), the following general formulas (2) to (5) are used. What is shown.
[0013]
[Chemical 3]

Among them, the compound represented by the general formula (6) of Chemical formula 4 is easy to obtain an optical coating film having a low refractive index and is easy to produce.
[0014]
[Formula 4]

Among the compounds represented by the general formula (6), those that are particularly preferably used in the present invention are compounds represented by an integer of n = 4 to 12 that have a low refractive index and are most easily produced. .
[0015]
Next, as a silane compound (B) having one isocyanate group and a plurality of hydrolyzable groups bonded to silicon in one molecule used in the present invention, a compound represented by the general formula (7) is given in Chemical Formula 5. It is done.
[0016]
[Chemical formula 5]

Among the compounds represented by the general formula (7), those most preferably used in the present invention are those represented by the general formulas (8) to (8) in view of crosslinkability, harmlessness of the reaction product and ease of production. The compound shown by 11) can be mention | raise | lifted.
[0017]
[Chemical 6]

The optical thin film of the present invention can contain a polyfunctional silane compound (D) for the purpose of improving performance such as hardness, adhesion to upper and lower layers, and adjustment of refractive index. The amount is 100 parts by weight of the crosslinkable fluorine-containing compound (C), and preferably 100 parts by weight of the polyfunctional silane compound (D), preferably not exceeding 90 parts by weight. When the polyfunctional silane compound (D) exceeds 100 parts by weight, the refractive index exceeds 1.46, and it tends to be difficult to obtain antireflection performance.
[0018]
As the polyfunctional silane compound (D), dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, Vinyltriethoxysilane or the like can be used alone or in admixture of two or more.
[0019]
Among the polyfunctional silane compounds (D), those having an epoxy group are preferably used for improving hardness and adhesion with the upper and lower layers. When the polyfunctional silane compound (D) has an epoxy group, 100 parts by weight of the polyfunctional epoxy resin (E) is preferably greater than 90 parts by weight with respect to 100 parts by weight of the crosslinkable fluorine-containing compound (C). None can be included. When the polyfunctional epoxy resin exceeds 100 parts by weight, the refractive index exceeds 1.46, and the antireflection performance intended by the present invention tends not to be obtained.
[0020]
As the polyfunctional epoxy resin (E), bisphenol A diglycidyl ether, novolac polyglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, or the like Use a mixture of the above.
[0021]
Next, the manufacturing method of a crosslinkable fluorine-containing compound (C) is demonstrated. The urethanization reaction between the compound (A) and the silane compound (B) is usually performed in an organic solvent having no group that reacts with an isocyanate group such as an ester group, a ketone group, an ether group, or a hydrocarbon group. The reaction temperature is preferably room temperature to about 80 ° C., and a urethanization catalyst such as di-n-butyltin dilaurate may be added. After the urethanization reaction, the solvent can be removed to take out the crosslinkable fluorine-containing compound (C), and the coating liquid can be adjusted to be used for forming an optical thin film. The chemical reaction is performed integrally. In the latter method, all or at least a part of the organic solvent is also used as a solvent for the coating liquid.
[0022]
The optical thin film of the present invention is formed by coating a base material with a coating solution obtained by dissolving each of the chemical substances described above in an alcohol, ester, ketone, ether, or hydrocarbon solvent.
As a pretreatment for the coating process, a silane hydrolyzable group usually contained in the coating liquid is hydrolyzed. Hydrolysis is generally carried out by adding an equivalent amount of water and stirring, but a trace amount of acid, particularly hydrochloric acid, is effective as a catalyst.
[0023]
A curing agent is added to the coating solution. The curing agent is a metal chelate compound such as aluminum, iron or copper having a long pot life, generally aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide monoethylacetoacetate, Aluminum-di-iso-propoxide monomethyl acetoacetate or the like is used. The addition amount of a hardening | curing agent is 0.1-20 weight part of the whole hardened | cured material composition, Preferably it is 0.2-10 weight part.
[0024]
In addition to this, an additive necessary according to the purpose of use, for example, a leveling agent or a coupling agent may be added to improve uniform coating properties and adhesion. The amount of the leveling agent or coupling agent added is 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on the entire cured product composition.
The coating method is not particularly limited as long as it can be uniformly applied to the substrate, and examples thereof include spin coating, dip coating, die coating, spray coating, bar coater coating, roll coating, curtain flow coating, and the like.
[0025]
The composition to be an optical thin film of the present invention is preferably cured by heat after being applied to a substrate with a uniform thickness. There is no restriction | limiting in the base material which can form the thin film of this invention. Above all, it is effective for preventing light reflection of ordinary glass and thin glass with a thickness of 1mm or less, plastic substrates such as polycarbonate and PMMA (polymethylmethacrylate), and transparent substrates such as polyethylene terephthalate film. Can be used. In addition, since it has excellent properties such as water repellency and oil repellency, a thin film using them may be formed. There is no particular limitation on the shape of the substrate.
[0026]
The base material can be subjected to a surface treatment or an intermediate layer for the purpose of, for example, improving adhesion and coating properties. If an optical thin film with a high refractive index is used for the intermediate film, the antireflection effect is enhanced, and a further excellent antireflection film can be obtained by alternately laminating a large number of high refractive index thin films and the optical thin film of the present invention. it can. The refractive index of the high refractive index film required for enhancing the antireflection effect should be equal to or higher than that of the substrate, preferably 1.58 or more, more preferably 1.6 or more, more preferably 1. 7 or more.
[0027]
A preferred treatment method performed before forming the optical thin film on the antireflection article will be described with reference to an embodiment. For example, a hard coat layer having a refractive index difference within ± 0.02 and a thickness of about 2 to 5 μm is formed on the surface of a polycarbonate or PMMA resin base material for the purpose of imparting hardness and eliminating interference fringes. Keep it. The hard coat layer is made of an organic or inorganic binder and, if necessary, fine metal oxide particles such as Si, Sb, Ce, Ti, and Sn, that is, fine particles generally having a particle diameter smaller than the wavelength of visible light A coating film to which is added is used. Examples of the organic binder include a cured epoxy resin and a resin obtained by radical crosslinking polymerization, and examples of the inorganic binder include a hydrolyzed cured product of a silane compound, but are not particularly limited. For curing, it is generally preferable to use a photocuring method rather than a heat curing method because the curing speed is high.
[0028]
In order to obtain high antireflection properties, the high refractive index thin film can be laminated on the hard coat layer. The thickness of the high refractive index film is 90 to 400 nm, more preferably 110 to 180 nm. In general, it contains metal oxides such as Sb, Ce, Ti, Sn, etc., and binders such as pentaerythritol triacrylate, (meth) acrylates such as 2-hydroxy-3-phenoxyacrylate, silanes, epoxy resins, etc. Formed as a layer. Use of a conductive metal oxide has an effect of imparting antistatic properties. For curing, it is generally preferable to use a photocuring method rather than a heat curing method because the curing speed is high.
[0029]
The thickness of the optical thin film is preferably an odd multiple of λ / 4n (λ: wavelength of light within the thin film, n: refractive index of the thin film). When the wavelength of light is wide, λ is based on the center wavelength of light. In the present invention, since the target light is usually visible light, the center wavelength is preferably set to 500 to 550 nm which is sensitive to humans.
[0030]
The film thickness of the optical thin film of the present invention is preferably 30 to 700 nm, more preferably 40 to 120 nm, although it depends on the refractive index of the thin film. When the film thickness of the optical thin film is less than 30 nm, the reflectance reduction due to the light interference effect in visible light may be insufficient. On the other hand, if the film thickness exceeds 700 nm, the reflectivity almost depends only on the reflection at the interface between the air and the thin film, and thus the reflectivity tends to be insufficiently reduced by the optical interference of visible light.
[0031]
【Example】
The present invention will be specifically described below with reference to examples. The evaluation means and measurement means used in the following examples and reference examples are as follows.
a. Film thickness: measured by ellipsometer.
b. Single-sided reflectance: The back surface of the measurement surface was roughened with sandpaper, then blacked with oil-based ink, and the reflectance of the measurement surface at 540 nm was measured using a spectrophotometer.
[0032]
c. Interference fringes: The samples were placed 20 cm below the fluorescent lamp stand and evaluated by visual observation.
d. Scratch resistance: Eraser (No. 50 (manufactured by Lion Corporation)) with a contact area of about 0.5 cm ² and a load of 1 kg, reciprocating 20 times on the reflective surface, and then visually judged and no scratch marks are observed. The pass was judged.
[0033]
Example 1
The composition liquid shown in Table 1 was prepared and reacted at 40 ° C. for 8 hours to obtain a solution R containing a crosslinkable fluorine-containing compound.
[0034]
[Table 1]

Using the solution R, a hydrolyzed solution having the following composition was prepared as a coating material A.
[0035]
Solution R 10 parts by weight Isopropanol 70 parts by weight 1/10 N hydrochloric acid 0.5 parts by weight The surface of a polycarbonate plate having a thickness of 2 mm was spin-coated with the coating material A, and heat-treated in an oven at 80 ° C. for 20 minutes. Subsequently, heat curing was performed in an oven at 130 ° C. for 2 hours to obtain a cured film having a thickness of 95 nm. When the refractive index of the obtained film was measured, it was nd = 1.42, and the single-sided reflectance was 1.3%.
[0036]
Reference example 1
The measurement result of the single-sided reflectance of the polycarbonate plate before coating was 5.2%.
[0037]
Example 2
The composition liquid shown in Table 2 was prepared and reacted at 40 ° C. for 8 hours to obtain a solution S containing a crosslinkable fluorine-containing compound.
[0038]
[Table 2]

Using the solution S, a hydrolyzate having the following composition was prepared as paint B.
[0039]
Solution S 10 parts by weight Isopropanol 60 parts by weight 1/10 N hydrochloric acid 0.3 parts by weight A cured film was obtained in the same manner as in Example 1. The refractive index of the obtained film was nd = 1.43, and the single-sided reflectance was 1.4%.
[0040]
Example 3
A hydrolyzate having the following composition containing a crosslinkable fluorine-containing compound was prepared as paint C.
10 parts by weight γ-glycidoxypropyltrimethoxysilane 7 parts by weight aluminum acetylacetonate 0.2 parts by weight isopropanol 83 parts by weight 1/10 N hydrochloric acid 2.7 Weight part A cured film was obtained in the same manner as in Example 1. The obtained film had a refractive index of nd = 1.46 and a single-sided reflectance of 1.8%.
[0041]
[Chemical 7]

Example 4
A hydrolyzate having the following composition containing a crosslinkable fluorine-containing compound was designated as paint D.
[0042]

A cured film was obtained in the same manner as in Example 1. The obtained film had a refractive index of nd = 1.45 and a single-sided reflectance of 1.7%.
[0043]
[Chemical 8]

Example 5
A hydrolyzate having the following composition containing a crosslinkable fluorine-containing compound was used as paint E.
[0044]
10 parts by weight γ-glycidoxypropylmethyldiethoxysilane 2 parts by weight Epicoat 827 2 parts by weight Aluminum acetylacetonate 0.1 parts by weight Isopropanol 86 parts by weight 1 / 10N hydrochloric acid 1.4 parts by weight A cured film was obtained in the same manner as in Example 1. The refractive index of the obtained film was nd = 1.46, and the single-sided reflectance at 540 nm was 1.8%.
[0045]
[Chemical 9]

Examples 6-10
On the surface of a polycarbonate plate having a thickness of 2 mm (refractive index: 1.59), an antimony oxide ultrafine particle having an average particle size (BET method) of 20 nm, pentaerythritol triacrylate, and 2-hydroxy-3-phenoxyacrylate are the main components. A photocured hard coat layer having a thickness of 3 μm and a refractive index of 1.59 was formed. In the same manner as in Example 1, paints A, B, C, D, and E were applied on the hard coat layer, and the results shown in Table 3 were obtained. All showed excellent scratch resistance.
[0046]
Examples 11-15
Main components of doped tin oxide ultrafine particles having an average particle size (BET method) of 50 nm, pentaerythritol triacrylate, and 2-hydroxy-3-phenoxyacrylate on the hard coat layer of the polycarbonate plate obtained in Examples 6 to 10 A conductive high refractive index layer having a thickness of 150 nm, a refractive index nd = 1.70, and a surface resistance value of 2 × 10 ⁹ Ω / □ was formed by photocuring. Further, in the same manner as in Example 1, coating materials A, B, C, D, and E were applied on the high refractive index layer and cured to obtain the results shown in Table 4. All showed high scratch resistance.
[0047]
[Table 3]

[0048]
[Table 4]

[0049]
【The invention's effect】
Since the optical thin film of the present invention is formed by curing a composition containing a low-refractive index and high-crosslinkable fluorine-containing compound, the visible light reflectance is low and high scratch resistance can be obtained. Further, since solution coating can be used, productivity is high and economical. Furthermore, there is a water / oil repellent effect by the effect of fluorine element. According to the present invention, an antireflection article excellent in scratch resistance and durability can be provided.

Claims (9)

Compound having at least one perfluoro group and a plurality of OH groups in one molecule (A
) And a silane compound (B) having one isocyanate group and a plurality of hydrolyzable groups bonded to silicon in one molecule, a crosslinkable fluorine-containing compound (C) An optical thin film characterized by being formed by curing a composition containing bismuth. The optical thin film according to claim 1, wherein the crosslinkable fluorine-containing compound (C) is represented by the general formula (1).

3. The optical thin film according to claim 1, wherein the polyfunctional silane compound (D) is contained in an amount of 0 to 100 parts by weight with respect to 100 parts by weight of the crosslinkable fluorine-containing compound (C). When the polyfunctional silane compound (D) has an epoxy group, the polyfunctional epoxy resin (E) is contained in an amount of 0 to 100 parts by weight with respect to 100 parts by weight of the crosslinkable fluorine-containing compound (C). The optical thin film according to claim 3. The optical thin film according to any one of claims 1 to 4, wherein the refractive index does not exceed 1.46 and the film thickness is 30 to 700 nm. An antireflection article, wherein the optical thin film according to any one of claims 1 to 5 is formed on a surface of a substrate. A hard coat layer composed of organic and / or inorganic binder and metal compound fine particles and having a refractive index within ± 0.02 of the refractive index of the substrate is formed between the substrate surface and the optical thin film. The antireflective article according to claim 6. The antireflective article according to claim 7, wherein a high refractive index film having a refractive index higher than that of the optical thin film and the hard coat layer is laminated between the hard coat layer and the optical thin film. . Compound having at least one perfluoro group and a plurality of OH groups in one molecule (A
) And a silane compound (B) having one isocyanate group and a plurality of hydrolyzable groups bonded to silicon in one molecule to urethanize to form a crosslinkable fluorine-containing compound (C
And a composition containing the obtained crosslinkable fluorine-containing compound (C) is prepared, coated on the surface of the substrate or the surface of the substrate film, and cured.