JP2004292754A - Anti-clouding coating material, coating film, and optical member using the film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare an anti-clouding coating film having a high hydrophilicity and absorbing capacity for moisture, and capable of maintaining a high hydrophilicity for a long period. <P>SOLUTION: The subject coating material for forming the anti-clouding coating film which consists of a porous film formed by using the anti-clouding coating material which contains (A) 0.1-5 pts. wt. polyorganosiloxane obtained by performing the hydrolysis or polycondensation of an organosilicon compound expressed by formula (I) [wherein, R<SP>1</SP>is a functional group having nitrogen atom; (m) is 1 or 2; and R<SP>2</SP>is a 1-4C alkyl], (B) 0.1-20 pts. wt. oxide fine particles and (C) 50-99.8 pts. wt. hydrophilic organic solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１３】
（式中、Ｒ^１ は窒素原子を有する官能基、ｍは１又は２を示す。Ｒ^２ は炭素数１〜４のアルキル基を示す。）
（Ｂ）酸化物微粒子０．１〜２０重量部、
（Ｃ）親水性有機溶媒５０〜９９．８重量部
を含有し、多孔質膜を形成することを特徴とする防曇性コーティング材料である。
【００１４】
前記ポリオルガノシロキサンと酸化物微粒子の重量比が１／２０〜１／４であることを特徴とする。
前記酸化物粒子径の平均粒子径が１〜３００ｎｍであることを特徴とする。
さらに光触媒性微粒子を含有し、該光触媒性微粒子の含有量が酸化物微粒子に対して０．５〜８０重量％であることを特徴とする。
【００１５】
本発明の第二の発明は、上記のコーティング材料を用いて形成した防曇性コーティング膜である。
【００１６】
本発明の第三発明は、基材上に上記のコーティング膜を形成したことを特徴とする防曇性光学部材である。
前記基材がガラス基材、金属基材、プラスチック基材またはセラミックス基材であることを特徴とする。
前記基材がガラスミラー、金属ミラーまたは蒸着プラスチックミラーであることを特徴とする。
【００１７】
本発明に関わる防曇性コーティング材料を用いて形成された防曇性コーティング膜は、酸化物粒子を、窒素原子を有する官能基を持つポリオルガノシロキサンによって固定化し、水などに対する耐久性が優れると共に、窒素原子を含有する官能基から由来する水との親和性、及び酸化物粒子に由来する多孔質による親水性の持続性を両立させることを可能とし、本発明に係わるコーティング膜を基材上に形成した光学部材は、先行技術を上回る有意義な効果を達成することを可能とした。
【００１８】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明の防曇性コーティング材料は、（Ａ）上記一般式（Ｉ）で表される有機ケイ素化合物を加水分解・縮重合させて得た窒素原子を有する官能基を持つポリオルガノシロキサン、（Ｂ）酸化物微粒子及び（Ｃ）親水性有機分散媒を含有し、且つ多孔質膜を形成することを特徴とする。
【００１９】
本発明に用いられる窒素原子を含有するポリオルガノシロキサンは、下記一般式（Ｉ）で表される有機ケイ素化合物を含むオルガノシランを水または加水分解に必要な量の水を含む親水性溶媒で加水分解・縮重合して得ることができる。
【００２０】
【化３】

【００２１】
一般式（Ｉ）において、Ｒ^１ は窒素原子を有する官能基を示し、１つまたは複数個の窒素原子を有する直鎖状または環状の基が挙げられる。窒素原子は、置換基を有していてもよいアミノ基、アミド基、イミド基、第四アンモニウム塩、ペプチド基、窒素原子を有する環状の基等の基となって含有されているのが好ましい。
【００２２】
Ｒ^２ は炭素数１〜４の直鎖状または分岐状のアルキル基を示す。
ｍは１又は２を示す。
【００２３】
用いられる上記の一般式（Ｉ）で表される化合物からなるオルガノシランの具体例として、Ｒ^１ が窒素原子を有する直鎖状の基の場合、Ｈ_２ ＮＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｈ_２ ＮＣＨ_２ ＳｉＣＨ_３ （ＯＣＨ_３ ）_２ 、Ｈ_２ ＮＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｈ_２ ＮＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｈ_２ ＮＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_２ ＣＨ_３ ）_３ 、ＨＮ（ＣＨ_３ ）ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、ＨＮ（ＣＨ_３ ）ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、ＨＮ（ＣＨ_３ ）ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、ＨＮ（ＣＨ_３ ）ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_２ ＣＨ_３ ）_３ 、Ｎ（ＣＨ_３ ）_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｎ（ＣＨ_３ ）_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｎ（ＣＨ_３ ）_２ ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_２ ＣＨ_３ ）_３ 、Ｃｌ⁻ Ｎ^＋ （ＣＨ_３ ）_３ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｃｌ⁻ Ｎ^＋ （ＣＨ_３ ）_３ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｃｌ⁻ Ｎ^＋ （ＣＨ_３ ）_３ ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｃｌ⁻ Ｎ^＋ （ＣＨ_３ ）_３ ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、Ｃｌ⁻ Ｎ^＋ （ＣＨ_３ ）_３ ＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_２ ＣＨ_３ ）_３ 、Ｃ_６ Ｈ_５ ＮＨＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、ＮＨ_２ ＣＯＮＨＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 、ＮＨ_２ ＣＨ_２ ＣＨ_２ ＮＨＣＨ_２ ＣＨ_２ ＣＨ_２ Ｓｉ（ＯＣＨ_３ ）_３ 等を挙げることができる。
【００２４】
また、一般式（Ｉ）で表される化合物からなるオルガノシランの具体例として、Ｒ^１ が窒素原子を有する環状の基の場合、以下の有機ケイ素化合物等を挙げることができる。
【００２５】
【化４】

【００２６】
更に、必要に応じて窒素原子を有する官能基に以下の反応などにより、官能基の特性をコントロールしても良い。
【００２７】
【化５】

【００２８】
ここで、Ｒ^３ は水素原子又はアルキル基である。Ｒ^４ は特に限定されないが、具体例として、−ＣＨ_２ ＯＨ、−ＣＨ_２ ＣＨ_２ ＯＨ、−ＣＨ_２ Ｏ（ＣＨ_２ ＣＨ_２ Ｏ）_ｎ Ｈ、−ＣＨ_２ ＯＣＨ_３ 、−ＣＨ_２ ＯＣ_２ Ｈ_５ などを挙げることができる。
【００２９】
更に、必要に応じ、親水性有機分散媒に分散可能なアルキルまたはフェニルシロキサンのオリゴマー成分またはこれらに対応の前駆体を本発明の防曇性コーティング材料に加えても良い。
【００３０】
一般式（Ｉ）で表される有機ケイ素化合物は水に可溶であり、水と混合させることより、加水分解・縮重合反応を行う。また、必要に応じて、加水分解に必要な量の水を含み、アルコール、エステル、ケトン、グリコール類などの溶媒で、加水分解・縮重合させてもよい。これにより、窒素原子を有する官能基を持つ、ポリオルガノシロキサンを得る。
【００３１】
窒素原子を有する官能基を持つポリオルガノシロキサンの含有量は０．１〜５重量部、好ましくは０．２〜４重量部である。窒素原子を有する官能基を持つポリオルガノシロキサンの含有量が０．１重量部未満であると、膜の機械的強度が弱くなる恐れがある。一方、含有量が５重量部より多いと、膜が緻密になり、初期の防曇性能が弱まる恐れがある。
【００３２】
本発明に用いられる酸化物粒子は、平均粒子径が１〜３００ｎｍであって、ポリオルガノシロキサンと複合化して透明な膜が得られれば、どんな酸化物粒子を使用してもよい。この酸化物粒子は、基本的に本発明の防曇性コーティング膜に多孔質の空隙を形成する。本発明に用いられる酸化物粒子は、平均粒子径が１〜３００ｎｍ、好ましくは５〜１００ｎｍ、より好ましく７〜４０ｎｍである。平均粒子径が１〜３００ｎｍであると、防曇性コーティング膜の透明性が損なわれる恐れがなく、多孔質を適宜形成し、コーティング材料の安定性の低下を防止することができる。
【００３３】
本発明に用いられる酸化物粒子は、取り扱い上、水やアルコールなどの分散媒に酸化物粒子を分散させた酸化物分散体の形態で用いるのが好ましい。酸化物粒子分散体としては、たとえば、酸化物コロイドゾルをあげることができる。入手しやすい酸化物コロイドゾルとしては、コロイダルシリカ、コロイダル酸化チタニウム、コロイダル酸化アルミニウム、酸化ジルコニウム等をあげることができる。これらは単独または２種以上を組み合わせて用いることができる。
【００３４】
コロイダルシリカの具体例として、日産化学工業株式会社が市販しているスノーテックス２０、スノーテックス３０、スノーテックスＣ、スノーテックスＮ、スノーテックスＯ、スノーテックスＣ等の水系ゾル銘柄、メタノールゾル、ＩＰＡ−ＳＴ、ＥＧ−ＳＴ、ＭＥＫ−ＳＴなどの溶剤系ゾル銘柄や、触媒化成工業株式会社が市販しているＯＳＣＡＬ−１１３２、ＯＳＣＡＬ−１４３２、ＯＳＣＡＬ−１２３２などの溶剤系ゾル銘柄などをあげることができる。コロイダル酸化アルミニウムの具体例としては、日産化学工業株式会社が市販しているアルミナゾル１００、アルミナゾル５２０などの銘柄を挙げることができる。
【００３５】
本発明のコーティング材料１００重量部において、酸化物粒子の含有量は０．１〜２０重量部、好ましくは０．３〜１５重量部である。０．１重量部未満では成膜の効率が低くなり、２０重量部をこえると、膜質が低下するので好ましくない。
【００３６】
酸化物粒子の分散性を向上させるために、必要に応じて、界面活性剤などを添加しても良い。酸化物粒子の状態を修飾するために、チタンの化合物、シランカップリング剤、β−ジケトン等のキレート剤、酢酸などの有機酸等を酸化物粒子分散体又は本発明の防曇性コーティング材料に添加しても良い。更に、これらの添加剤を用いて事前に修飾した酸化物粒子を水やアルコールなどの分散媒に分散して用いても良い。
【００３７】
なお、ポリオルガノシロキサン／酸化物粒子の重量比が１／２０〜１／４、好ましくは１／１５〜２／９である。ポリオルガノシロキサン／微粒子の重量比が１／４より小さいと、粒子間の空隙が存在し、多孔質の構造を形成する。一方、ポリオルガノシロキサン／酸化物微粒子の重量比が１／２０より高いと、多孔質構造の機械的強度が低くなる恐れが無くなる。
【００３８】
本発明の防曇性コーティング材料には、所望の場合は、酸化物粒子に光触媒機能を有する酸化物粒子を用いることができる。光触媒粒子を用いる場合には、光触媒粒子のバンドギャップより短い波長の光によって、光触媒粒子が励起され、これにより本発明の防曇性コーティング膜の酸化能力が向上する。これによって、コーティング膜表面に付着した有機成分は自然光に含まれる紫外線により励起された光触媒粒子により、分解が促進され、表面の防曇性が向上し、持続する。
【００３９】
本発明に用いることができる光触媒粒子としては、一般的には、平均粒子径が１〜３００ｎｍ、好ましくは平均粒子径が３〜１００ｎｍである。平均粒子径が１〜３００ｎｍである場合には、上述した理由で防曇性コーティング膜の透明性が損なわれる恐れがなく、光触媒粒子の性能が発現される。
【００４０】
光触媒粒子としては、例えば、アナターゼ型酸化チタン、ルチル型酸化チタン、酸化亜鉛、酸化すず、酸化第二鉄、三酸化二ビスマス、三酸化タングステン、およびチタン酸ストロンチウム等を挙げることができる。特に、アナターゼ型酸化チタンは市場で簡単に入手することができる。アナターゼ酸化チタンの具体例として、例えば、多木化学株式会社が市販している酸化チタンゾル、Ｍ−６、Ａ−６等の銘柄、テイカ株式会社が市販しているＳＴＫ−２５１等の銘柄等を用いることができる。
【００４１】
本発明の防曇性コーティング材料に添加する光触媒性微粒子の含有量は、酸化物微粒子に対して０．５〜８０重量％、より好ましくは０．５〜５０重量％である。光触媒粒子の量が０．５〜８０重量％である場合には、塗膜の屈折率が高くなりすぎることが無く、膜の機械的性質も維持される。
【００４２】
本発明において、分散媒としては、親水性有機溶媒が用いられ、必要に応じて水や芳香族類溶媒を併用する。
親水性有機分散媒の具体例としては、メタノール、エタノール、１―プロパノール、２―プロパノールなどのアルコール類、酢酸メチル、酢酸エチル、アセト酢酸エチルなどのエステル類、アセトン、メチルエチルケトンなどのケトン類、エチレングリコール、グリセリン、エチレングリコールモノアセテート、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテルグリコール、エチレングリコールモノブチルエーテルなどの多価アルコール及びそれらの誘導体を挙げることができる。
【００４３】
本発明の防曇性コーティング材料の１００重量部において、分散媒とする親水性有機分散媒の含有量は５０重量部以上、より好ましくは６５重量部以上である。親水性有機分散媒の量が５０重量部以上であると、防曇性コーティング膜の膜質が低下する恐れがなくなる。
【００４４】
コーティング材料の全固形分濃度は０．２〜２５重量％、より好ましく０．５〜１０重量％である。固形分濃度が０．２〜２５重量％であると、膜の形成効率が高く、経済性において有利であり、またコーティング液の貯存安定性がよく、形成される防曇性コーティング膜の膜質が高くなる。
【００４５】
本発明の防曇性コーティング材料は、窒素原子を有するポリオルガノシロキサン、酸化物粒子、親水性有機分散媒、所望の場合は、光触媒粒子及びその他の添加剤を所定量配合し、これを混合することにより製造することができる。混合方法は、特に限定されず、公知の方法の中から、本発明の防曇性コーティング材料に適した方法を採用することができる。
【００４６】
本発明の防曇性コーティング材料の塗膜形成方法としては、通常のスプレーコーティング法、ロールコーティング法、ディプコーティング法などを挙げることができる。なお、これらに限定されるものではなく、本発明の防曇性コーティング材料に適した方法を採用すればよい。
【００４７】
本発明の防曇性コーティング材料の塗膜の硬化方法は、特に限定されず、公知の方法によればよいが、通常は加熱硬化方法を用いることができる。硬化温度は用いる窒素原子を有するポリオルガノシロキサンの硬化性や基材の軟化温度などによって適切な温度を定めればよく、特に限定されるものではない。
【００４８】
本発明に用いることのできる基材は特に限定されないが、ガラス基材、セラミック基材、金属基材、プラスチック基材等の基材を挙げることができる。ガラス基材の具体例としては、透明ガラス基材、ガラスレンズ、ガラスフィルター、ガラスミラー等の光学基材を挙げることができる。プラスチック基材の具体例としては、透光板、プラスチックレンズなどをあげることができる。金属基材の具体例としては、熱交換フィルター、金属ミラー等を、セラミック基材としては、タイルを挙げることができる。
【００４９】
本発明の防曇性コーティング膜との基材との密着性を向上させるために、必要に応じて事前に基材の表面をプレコートしても良い。
コーティング基材は、特に限定されないが、光学部材、透明基板、反射性基板などに適用できる。例として、ガラス基板、ガラスレンズ、ガラスフィルター、ガラスミラー、金属、金属ミラー、タイル等をあげることができる。コーティング層と基板との密着性をあげるために、必要に応じて事前に基材の表面をプライマー処理して良い。
【００５０】
このように得た防曇性のコーティング膜は多孔質であり、細孔表面にアミノ基などの窒素原子を含有する官能基を有する。これによって、本発明の防曇性のコーティング膜は初期から高い親水性を示し、従来の架橋性ポリマーと比べてより高い防曇性を継続することができる。
【００５１】
コーティング膜の多孔質度に関しては、例えばＦＴ−ＳＥＭ（走査型電子顕微鏡）などによる表面または断面の直接観察で確認できる細孔が存在することが好ましい。
【００５２】
【実施例】
以下に合成例および実施例を挙げて本発明を具体的に説明する。
【００５３】
合成例１
７０％のメタノール水溶液１００ｇに攪拌しながら、４０ｇのＨ_２ Ｎ（ＣＨ_２ ）_２ ＨＮ（ＣＨ_２ ）_３ Ｓｉ（ＯＣＨ_３ ）_３ を２０分間かけて加えた。その後、オイルバスで６０℃、１時間保持した。放冷して、約１４０ｇの窒素原子を有するポリオルガノシロキサン分散液（Ｎ１：濃度約２１重量％）を得た。
【００５４】
合成例２
２０ｇのＨ_２Ｎ（ＣＨ_２）_３Ｓｉ（ＯＣＨ_３）_３、２０ｇのＨ_２Ｎ（ＣＨ_２）_２ＨＮ（ＣＨ_２）_３Ｓｉ（ＣＨ_３）（ＯＣＨ_３）_２と、１０ｇの２，３−エポキシ−１−プロパノールを混合し、５０℃で約５時間反応させた。これにより、一部のアミノ基をエポキシ基により部分的に修飾した。得られた混合液を７０％のメタノール水溶液１００ｇに攪拌しながら、２０分間かけて加えた。その後、オイルバスで６０℃、１時間保持した。放冷して、約１４５ｇの窒素原子を有するポリオルガノシロキサン分散液（Ｎ２：濃度約２５重量％）を得た。
【００５５】
合成例３
４０ｇの下記の有機ケイ素化合物を
【００５６】
【化６】

【００５７】
を７０％のメタノール水溶液１００ｇに攪拌しながら、２０分かけて添加した。約１４０ｇの窒素原子を有するポリオルガノシロキサン分散液（Ｎ３：濃度約２１重量％）を得た。
【００５８】
実施例１
５６ｇのイソプロピルアルコールに４ｇのＮ１ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、２０ｇのスノーテックスＣＭ（コロイダルシリカ、平均粒子径２０〜３０ｎｍ、濃度３０重量％、日産化学工業（株）製）を加えた。２時間攪拌し、コーティング液１を得た。この液を用いて、ガラス基板を引き上げ速度４０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行った。
【００５９】
このサンプルを息吹きで評価したところ、コーティングした部分は曇らなかった。更に、空気中（温度２５℃、相対湿度約５５％）に１０日間保存したところ、未コーティングの部分は防曇性がなかったが、コーティングした部分には、防曇性が維持されていた。サンプルの断面を電子顕微鏡で観察したところ、コーティング膜は多孔質であって、膜厚が約０．３μｍであった。
【００６０】
実施例２
５８ｇのイソプロピルアルコールに２ｇのＮ２ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、２０ｇのスノーテックスＣＭ（日産化学工業（株））を加えた。２時間攪拌し、コーティング液２を得た。この液を用いて、ガラス基板を引き上げ速度４０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行った。
【００６１】
このサンプルを息吹きで評価したところ、コーティングした部分は曇らなかった。更に、空気中に１０日間保存したところ、未コーティングの部分は防曇性がなかったが、コーティングした部分には、防曇性が維持されていた。サンプルの断面を電子顕微鏡で観察したところ、コーティング膜は多孔質であって、膜厚が約０．３μｍであった。
【００６２】
実施例３
６０ｇのイソプロピルアルコールに４ｇのＮ１ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、１５ｇのスノーテックスＣＭを加えた後、２５ｇの光触媒ゾルＡ−６溶液（成分：アナターゼ型酸化チタン、平均粒子径５ｎｍ、濃度：６重量％、多木化学株式会社製）を添加した。２時間攪拌し、コーティング液３を得た。この液を用いて、ガラス基板を引き上げ速度４０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行い、光触媒含有のコーティングサンプルを得た。
【００６３】
このサンプルを屋外（温度：１０〜２５℃、相対湿度：３０〜７０％）で１０日間暴露したところ、未コーティングの部分は防曇性がなかったが、コーティングした部分には、防曇性が維持されていた。サンプルの断面を電子顕微鏡で観察したところ、コーティング膜は多孔質であって、膜厚が約０．３μｍであった。
【００６４】
実施例４
６０ｇのイソプロピルアルコールに１ｇのＮ３ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、２０ｇのシリカゾル（日産化学工業（株）、ＳＴ−ＩＰＡ、平均粒子径１０〜２０ｎｍ、濃度３０重量％）を加えた。２時間攪拌し、コーティング液４を得た。この液を用いて、ガラス基板を引き上げ速度３０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行った。
【００６５】
このサンプルを息吹きで評価したところ、コーティングした部分は曇らなかった。更に、空気中に１０日間保存したところ、未コーティングの部分は防曇性がなかったが、コーティングした部分には、防曇性が維持されていた。サンプルの断面を電子顕微鏡で観察したところ、コーティング膜は多孔質であって、膜厚が約０．２５μｍであった。
【００６６】
実施例５
６０ｇイソプロピルアルコールに３ｇのＮ２ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、攪拌しながら、２０ｇのシリカゾルと１０ｇの光触媒ゾルＡ−６を加えた。２時間攪拌し、コーティング液５を得た。この液を用いて、ガラス基板を引き上げ速度３０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行った。
【００６７】
このサンプルを息吹きで評価したところ、コーティングした部分は曇らなかった。更に、屋外で１０日間静置ところ、未コーティングの部分は防曇性がなかったが、コーティングした部分には、防曇性が維持されていた。サンプルの断面を電子顕微鏡で観察したところ、コーティング膜は多孔質であって、膜厚が約０．２５μｍであった。
【００６８】
比較例１
エタノール７２０重量部に攪拌しながら、エチルシリケートのオリゴマー液１４０重量部（コルコート株式会社、エチルシリケート４０）を加え、更に０．０１Ｎ塩酸水溶液１４０重量部をゆっくり添加した。その後、１日間室温反応した後、コーティング液とした。ガラス基板を部分的にディップコーティングし、１５０℃で１時間熱処理した。
【００６９】
得たガラスサンプルを室温で空気中に１週間静置した。息吹きし、目視で観察したところ、コーティング部分も未コーティング部分も曇った。何れも防曇性が無いことがわかった。これは、シリカ膜に空気中の有機質の物質を吸着し、表面の親水性が低下したと考えられる。
【００７０】
比較例２
６０ｇエタノールに２０ｇのＮ３ポリオルガノシロキサン溶液を攪拌しながら、添加した。その後、２０ｇの光触媒ゾルＡ−６を加えた。２時間攪拌し、コーティング液を得た。この液を用いて、ガラス基板を引き上げ速度３０ｍｍ／分でディップコーティングし、１２０℃で１時間をかけて熱処理を行った。これらのサンプルを空気中に１０日間保存したところ、表面の防曇性が無くなった。
【００７１】
【発明の効果】
以上説明した様に、本発明の防曇性被膜用のコーティン材料は、コーティングした部材の表面が高い親水性をもち、耐水性も優れている。
また、本発明の防曇性コーティング膜は、コーティン膜が多孔質なので、吸水性もあり、長期間にわたって高い親水性を保持することができ、湿度が変化する環境下でも、表面が曇らなく、水膜の形成が抑えられる。
また、本発明は、上記の防曇性コーティング膜を用いた防曇性に優れた光学部材を提供できる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an antifogging coating material, an antifogging coating film and an antifogging optical member, and particularly to coating a transparent substrate such as glass or plastic and a substrate such as a glass mirror having a reflection function. Accordingly, the present invention relates to an antifogging coating material, an antifogging coating film, and an antifogging optical member which form an antifogging film having high film strength and continuously maintaining antifogging property.
[0002]
[Prior art]
BACKGROUND ART Conventionally, transparent substrates such as inorganic glass have been widely used for optical members such as camera lenses and mirrors. However, when these substrates are exposed to a humid atmosphere, they condense on their surface, which refracts or reflects light, impairing their function and impairing their aesthetics. In particular, everyday optical members such as glasses, goggles, and camera lenses are required to have high performance antifogging properties and sustainability. Attempts have been made to provide a coating film on the surface of such a substrate to impart hydrophilicity or water repellency to the surface.
[0003]
As one method, it is known to make a surface hydrophilic by providing a hydrophilic film obtained by crosslinking a hydrophilic polymer on the surface of a substrate. For example, Patent Document 1 discloses an antifogging coating material comprising a mixture of at least one selected from inorganic alkoxides and hydrolytic polycondensates of inorganic alkoxides, and polyacrylic acids and polyvinyl alcohol. Have been. However, the antifogging coating film formed using such a coating material has excellent water absorption performance, but has a problem of low strength.
[0004]
Patent Document 2 discloses that a thin film formed on the surface of a glass substrate is coated with a solution obtained by mixing a metal alkoxide compound or a liquid in which oxide fine particles having a low equilibrium water vapor are dispersed and a metal alkoxide compound. , A solution that has undergone hydrolysis and polycondensation reactions in the presence of a water-soluble organic polymer together with water and an acid is used as a coating solution, the coating solution is applied to form a film, dried, and then mixed with water or an alcohol and water. An antifogging coating characterized by washing an organic polymer with a liquid and baking by heating at a high temperature to obtain an oxide thin film having a porous structure is disclosed. However, there is a problem that a complicated process is required to produce the anti-fogging thin film, and there is a problem that suitable members are also limited.
[0005]
As another method for imparting surface hydrophilicity, attention has been paid to a technique for hydrophilizing a film using a photo-oxidation catalyst represented by titanium oxide. Patent Literature 3 includes a transparent base material, and a layer including a substantially transparent photocatalytic semiconductor material bonded to a surface of the base material, wherein the photocatalytic material has a surface which is responsive to photoexcitation. In order to prevent the condensed water and / or water droplets from adhering to the surface of the layer and to prevent the substrate from being clouded or overshadowed by the water and / or water droplets. A fogging member is disclosed.
[0006]
It is said that a silicone resin is suitable for the binder of the photocatalyst because radicals having strong oxidizing ability are generated around the photocatalyst by light irradiation, and the photocatalyst oxidizes the binder resin. Patent Document 4 discloses an aqueous solvent-based coating composition containing a nitrogen atom-containing organosilicon compound obtained by hydrolyzing an organosilane, water, and photocatalyst fine particles. Such a coating composition is expected to be hydrophilic by a photocatalyst. However, such a silicone or modified silicone film containing a photocatalyst has a problem in that the degree of exposure of the catalyst particles is small, and in order to exhibit the performance of the photocatalyst, strong ultraviolet irradiation is required.
[0007]
Further, in Patent Document 5, an outermost layer provided on a substrate is a composite film containing titania and an amorphous metal oxide, and the composite film contains fine particles of silica and / or alumina. A hydrophilic coating characterized by this is disclosed. Since this coating also contains titania having photocatalytic activity, the surface can be expected to be hydrophilic by light irradiation, but if left in a dark place for a long time, dirt components in the air will adhere and anti-fogging will occur. However, there remains a problem that the property is lost.
[0008]
[Patent Document 1]
JP-A-11-61029
[Patent Document 2]
JP-A-9-295835
[Patent Document 3]
WO96-29375
[Patent Document 4]
JP-A-11-90315
[Patent Document 5]
JP-A-10-68091
[0009]
[Problems to be solved by the invention]
However, in the above-mentioned conventional techniques, it is hard to say that the strength of the film, the affinity for moisture, and the durability of the hydrophilicity are all satisfied, and the use thereof has been limited.
[0010]
The present invention has been made in order to solve such disadvantages of the prior art, and has a high hydrophilicity, a water absorbing ability, and an antifogging coating capable of maintaining a high hydrophilicity for a long period of time. It is an object to provide a film, an optical member having the antifogging coating film, and an antifogging coating material for forming the antifogging coating film.
[0011]
[Means for Solving the Problems]
The present invention can be specified by the following items.
That is, the first invention of the present invention is a coating material for forming an antifogging film,
(A) 0.1 to 5 parts by weight of a polyorganosiloxane having a functional group having a nitrogen atom obtained by hydrolysis and condensation polymerization of an organosilicon compound represented by the following general formula (I);
[0012]
Embedded image

[0013]
(Where R ¹ Represents a functional group having a nitrogen atom, and m represents 1 or 2. R ² Represents an alkyl group having 1 to 4 carbon atoms. )
(B) 0.1 to 20 parts by weight of oxide fine particles,
(C) 50 to 99.8 parts by weight of a hydrophilic organic solvent
And forming a porous film.
[0014]
The weight ratio of the polyorganosiloxane to the oxide fine particles is from 1/20 to 1/4.
The average particle diameter of the oxide particles is 1 to 300 nm.
Furthermore, it contains photocatalytic fine particles, and the content of the photocatalytic fine particles is 0.5 to 80% by weight based on the oxide fine particles.
[0015]
The second invention of the present invention is an antifogging coating film formed using the above-mentioned coating material.
[0016]
A third invention of the present invention is an antifogging optical member comprising the above-mentioned coating film formed on a substrate.
The substrate is a glass substrate, a metal substrate, a plastic substrate or a ceramic substrate.
The substrate is a glass mirror, a metal mirror or a vapor-deposited plastic mirror.
[0017]
The anti-fogging coating film formed using the anti-fogging coating material according to the present invention has oxide particles immobilized with a polyorganosiloxane having a functional group having a nitrogen atom, and has excellent durability against water and the like. It is possible to achieve both affinity for water derived from a functional group containing a nitrogen atom, and durability of hydrophilicity due to porosity derived from oxide particles, and apply a coating film according to the present invention on a substrate. The optical member formed in (1) has achieved a significant effect over the prior art.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The antifogging coating material of the present invention comprises (A) a polyorganosiloxane having a functional group having a nitrogen atom obtained by hydrolyzing and polycondensing the organosilicon compound represented by the above general formula (I); ) Containing oxide fine particles and (C) a hydrophilic organic dispersion medium and forming a porous film.
[0019]
The nitrogen-containing polyorganosiloxane used in the present invention is obtained by hydrolyzing an organosilane containing an organosilicon compound represented by the following general formula (I) with water or a hydrophilic solvent containing water in an amount necessary for hydrolysis. It can be obtained by decomposition and condensation polymerization.
[0020]
Embedded image

[0021]
In the general formula (I), R ¹ Represents a functional group having a nitrogen atom, and examples thereof include a linear or cyclic group having one or more nitrogen atoms. The nitrogen atom is preferably contained as an optionally substituted amino group, an amide group, an imide group, a quaternary ammonium salt, a peptide group, a cyclic group having a nitrogen atom, or the like. .
[0022]
R ² Represents a linear or branched alkyl group having 1 to 4 carbon atoms.
m represents 1 or 2.
[0023]
Specific examples of the organosilane comprising the compound represented by the above general formula (I) used include R ¹ Is a linear group having a nitrogen atom, ₂ NCH ₂ Si (OCH ₃ ) ₃ , H ₂ NCH ₂ SiCH ₃ (OCH ₃ ) ₂ , H ₂ NCH ₂ CH ₂ Si (OCH ₃ ) ₃ , H ₂ NCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , H ₂ NCH ₂ CH ₂ CH ₂ Si (OCH ₂ CH ₃ ) ₃ , HN (CH ₃ ) CH ₂ Si (OCH ₃ ) ₃ , HN (CH ₃ ) CH ₂ CH ₂ Si (OCH ₃ ) ₃ , HN (CH ₃ ) CH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , HN (CH ₃ ) CH ₂ CH ₂ CH ₂ Si (OCH ₂ CH ₃ ) ₃ , N (CH ₃ ) ₂ CH ₂ Si (OCH ₃ ) ₃ , N (CH ₃ ) ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , N (CH ₃ ) ₂ CH ₂ CH ₂ CH ₂ Si (OCH ₂ CH ₃ ) ₃ , Cl ⁻ N ⁺ (CH ₃ ) ₃ CH ₂ Si (OCH ₃ ) ₃ , Cl ⁻ N ⁺ (CH ₃ ) ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , Cl ⁻ N ⁺ (CH ₃ ) ₃ CH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , Cl ⁻ N ⁺ (CH ₃ ) ₃ CH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , Cl ⁻ N ⁺ (CH ₃ ) ₃ CH ₂ CH ₂ CH ₂ Si (OCH ₂ CH ₃ ) ₃ , C ₆ H ₅ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , NH ₂ CONHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , NH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ And the like.
[0024]
Specific examples of the organosilane comprising the compound represented by the general formula (I) include R ¹ Is a cyclic group having a nitrogen atom, the following organosilicon compounds can be exemplified.
[0025]
Embedded image

[0026]
Further, if necessary, the characteristics of the functional group may be controlled by the following reaction with the functional group having a nitrogen atom.
[0027]
Embedded image

[0028]
Where R ³ Is a hydrogen atom or an alkyl group. R ⁴ Is not particularly limited, but as a specific example, -CH ₂ OH, -CH ₂ CH ₂ OH, -CH ₂ O (CH ₂ CH ₂ O) _n H, -CH ₂ OCH ₃ , -CH ₂ OC ₂ H ₅ And the like.
[0029]
Further, if necessary, an alkyl or phenylsiloxane oligomer component dispersible in a hydrophilic organic dispersion medium or a precursor corresponding thereto may be added to the antifogging coating material of the present invention.
[0030]
The organosilicon compound represented by the general formula (I) is soluble in water, and undergoes a hydrolysis / condensation polymerization reaction when mixed with water. Further, if necessary, the composition may be hydrolyzed and polycondensed with a solvent such as an alcohol, an ester, a ketone, or a glycol containing water in an amount necessary for the hydrolysis. Thereby, a polyorganosiloxane having a functional group having a nitrogen atom is obtained.
[0031]
The content of the polyorganosiloxane having a functional group having a nitrogen atom is 0.1 to 5 parts by weight, preferably 0.2 to 4 parts by weight. If the content of the polyorganosiloxane having a functional group having a nitrogen atom is less than 0.1 part by weight, the mechanical strength of the film may be reduced. On the other hand, when the content is more than 5 parts by weight, the film becomes dense, and the initial antifogging performance may be weakened.
[0032]
As the oxide particles used in the present invention, any oxide particles may be used as long as they have an average particle diameter of 1 to 300 nm and a transparent film can be obtained by complexing with the polyorganosiloxane. These oxide particles basically form porous voids in the antifogging coating film of the present invention. The oxide particles used in the present invention have an average particle diameter of 1 to 300 nm, preferably 5 to 100 nm, more preferably 7 to 40 nm. When the average particle size is from 1 to 300 nm, the transparency of the anti-fogging coating film is not likely to be impaired, the porous material is appropriately formed, and a decrease in the stability of the coating material can be prevented.
[0033]
The oxide particles used in the present invention are preferably used in the form of an oxide dispersion in which the oxide particles are dispersed in a dispersion medium such as water or alcohol for handling. Examples of the oxide particle dispersion include an oxide colloid sol. Examples of readily available oxide colloid sols include colloidal silica, colloidal titanium oxide, colloidal aluminum oxide, and zirconium oxide. These can be used alone or in combination of two or more.
[0034]
Specific examples of colloidal silica include water-based sol brands such as Snowtex 20, Snowtex 30, Snowtex C, Snowtex N, Snowtex O, and Snowtex C, marketed by Nissan Chemical Industries, methanol sol, IPA Solvent-based sol brands such as -ST, EG-ST, MEK-ST and the like, and solvent-based sol brands such as OSCAL-1132, OSCAL-1432, and OSCAL-1232, which are commercially available from Catalyst Chemical Industry Co., Ltd. it can. Specific examples of the colloidal aluminum oxide include brands such as alumina sol 100 and alumina sol 520 which are commercially available from Nissan Chemical Industries, Ltd.
[0035]
In 100 parts by weight of the coating material of the present invention, the content of the oxide particles is 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight. If the amount is less than 0.1 part by weight, the efficiency of film formation is lowered, and if it exceeds 20 parts by weight, the film quality is undesirably reduced.
[0036]
In order to improve the dispersibility of the oxide particles, a surfactant or the like may be added as necessary. In order to modify the state of the oxide particles, a compound of titanium, a silane coupling agent, a chelating agent such as β-diketone, an organic acid such as acetic acid, or the like is added to the oxide particle dispersion or the antifogging coating material of the present invention. It may be added. Further, oxide particles modified in advance with these additives may be used by dispersing them in a dispersion medium such as water or alcohol.
[0037]
The weight ratio of polyorganosiloxane / oxide particles is 1/20 to 1/4, preferably 1/15 to 2/9. When the weight ratio of polyorganosiloxane / fine particles is smaller than 1/4, voids exist between the particles, forming a porous structure. On the other hand, when the weight ratio of polyorganosiloxane / oxide fine particles is higher than 1/20, there is no possibility that the mechanical strength of the porous structure is reduced.
[0038]
In the antifogging coating material of the present invention, if desired, oxide particles having a photocatalytic function can be used. When photocatalyst particles are used, the photocatalyst particles are excited by light having a wavelength shorter than the band gap of the photocatalyst particles, thereby improving the oxidation ability of the antifogging coating film of the present invention. As a result, the organic component attached to the surface of the coating film is accelerated by the photocatalyst particles excited by the ultraviolet light contained in the natural light, whereby the decomposition is promoted, and the antifogging property of the surface is improved and maintained.
[0039]
The photocatalyst particles that can be used in the present invention generally have an average particle size of 1 to 300 nm, preferably 3 to 100 nm. When the average particle size is from 1 to 300 nm, the performance of the photocatalyst particles is exhibited without the possibility that the transparency of the antifogging coating film is impaired for the above-mentioned reason.
[0040]
Examples of the photocatalyst particles include anatase-type titanium oxide, rutile-type titanium oxide, zinc oxide, tin oxide, ferric oxide, bismuth trioxide, tungsten trioxide, and strontium titanate. In particular, anatase-type titanium oxide can be easily obtained on the market. Specific examples of anatase titanium oxide include, for example, titanium oxide sol marketed by Taki Chemical Co., Ltd., brands such as M-6 and A-6, brands such as STK-251 marketed by Teica Corporation, and the like. Can be used.
[0041]
The content of the photocatalytic fine particles added to the antifogging coating material of the present invention is 0.5 to 80% by weight, more preferably 0.5 to 50% by weight, based on the oxide fine particles. When the amount of the photocatalyst particles is 0.5 to 80% by weight, the refractive index of the coating film does not become too high, and the mechanical properties of the film are maintained.
[0042]
In the present invention, a hydrophilic organic solvent is used as a dispersion medium, and water and an aromatic solvent are used in combination as necessary.
Specific examples of the hydrophilic organic dispersion medium include alcohols such as methanol, ethanol, 1-propanol and 2-propanol; esters such as methyl acetate, ethyl acetate and ethyl acetoacetate; ketones such as acetone and methyl ethyl ketone; and ethylene. Examples include polyhydric alcohols such as glycol, glycerin, ethylene glycol monoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether glycol, and ethylene glycol monobutyl ether, and derivatives thereof.
[0043]
In 100 parts by weight of the antifogging coating material of the present invention, the content of the hydrophilic organic dispersion medium as the dispersion medium is 50 parts by weight or more, more preferably 65 parts by weight or more. When the amount of the hydrophilic organic dispersion medium is 50 parts by weight or more, there is no possibility that the quality of the antifogging coating film is deteriorated.
[0044]
The total solids concentration of the coating material is 0.2 to 25% by weight, more preferably 0.5 to 10% by weight. When the solid concentration is 0.2 to 25% by weight, the efficiency of film formation is high, which is advantageous in economy, and the storage stability of the coating solution is good, and the quality of the formed antifogging coating film is low. Get higher.
[0045]
The antifogging coating material of the present invention is prepared by mixing a predetermined amount of a polyorganosiloxane having a nitrogen atom, oxide particles, a hydrophilic organic dispersion medium, and, if desired, photocatalyst particles and other additives, and mixing them. It can be manufactured by the following. The mixing method is not particularly limited, and a method suitable for the antifogging coating material of the present invention can be adopted from known methods.
[0046]
Examples of the method for forming a coating film of the antifogging coating material of the present invention include a usual spray coating method, a roll coating method, and a dip coating method. The present invention is not limited to these, and a method suitable for the antifogging coating material of the present invention may be employed.
[0047]
The method for curing the coating film of the antifogging coating material of the present invention is not particularly limited, and may be a known method, but usually a heat curing method can be used. The curing temperature may be appropriately determined depending on the curability of the polyorganosiloxane having a nitrogen atom to be used, the softening temperature of the substrate, and the like, and is not particularly limited.
[0048]
The substrate that can be used in the present invention is not particularly limited, and examples thereof include substrates such as a glass substrate, a ceramic substrate, a metal substrate, and a plastic substrate. Specific examples of the glass substrate include optical substrates such as a transparent glass substrate, a glass lens, a glass filter, and a glass mirror. Specific examples of the plastic substrate include a light transmitting plate and a plastic lens. Specific examples of the metal substrate include a heat exchange filter and a metal mirror, and examples of the ceramic substrate include a tile.
[0049]
In order to improve the adhesion between the anti-fogging coating film of the present invention and the substrate, the surface of the substrate may be pre-coated as needed.
The coating substrate is not particularly limited, but can be applied to an optical member, a transparent substrate, a reflective substrate, and the like. Examples include glass substrates, glass lenses, glass filters, glass mirrors, metals, metal mirrors, tiles, and the like. In order to increase the adhesion between the coating layer and the substrate, the surface of the substrate may be subjected to a primer treatment beforehand if necessary.
[0050]
The anti-fogging coating film thus obtained is porous, and has a functional group containing a nitrogen atom such as an amino group on the surface of the pore. Accordingly, the anti-fogging coating film of the present invention exhibits high hydrophilicity from the beginning, and can maintain higher anti-fogging property than the conventional crosslinkable polymer.
[0051]
Regarding the porosity of the coating film, for example, it is preferable that pores that can be confirmed by direct observation of the surface or the cross section by FT-SEM (scanning electron microscope) or the like are present.
[0052]
【Example】
Hereinafter, the present invention will be described specifically with reference to Synthesis Examples and Examples.
[0053]
Synthesis Example 1
While stirring in 100 g of a 70% aqueous methanol solution, 40 g of H ₂ N (CH ₂ ) ₂ HN (CH ₂ ) ₃ Si (OCH ₃ ) ₃ Was added over 20 minutes. Thereafter, the temperature was maintained at 60 ° C. for 1 hour in an oil bath. After cooling, about 140 g of a nitrogen-containing polyorganosiloxane dispersion liquid (N1: concentration: about 21% by weight) was obtained.
[0054]
Synthesis Example 2
20 g of H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , 20g of H ₂ N (CH ₂ ) ₂ HN (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ And 10 g of 2,3-epoxy-1-propanol were mixed and reacted at 50 ° C. for about 5 hours. As a result, some amino groups were partially modified with epoxy groups. The obtained mixture was added to 100 g of a 70% aqueous methanol solution with stirring for 20 minutes. Thereafter, the temperature was maintained at 60 ° C. for 1 hour in an oil bath. After cooling, about 145 g of a polyorganosiloxane dispersion having nitrogen atoms (N2: concentration of about 25% by weight) was obtained.
[0055]
Synthesis Example 3
40 g of the following organosilicon compound
[0056]
Embedded image

[0057]
Was added to 100 g of a 70% aqueous methanol solution with stirring over 20 minutes. About 140 g of a polyorganosiloxane dispersion having nitrogen atoms (N3: concentration: about 21% by weight) was obtained.
[0058]
Example 1
4 g of N1 polyorganosiloxane solution was added to 56 g of isopropyl alcohol with stirring. Thereafter, 20 g of Snowtex CM (colloidal silica, average particle diameter 20 to 30 nm, concentration 30% by weight, manufactured by Nissan Chemical Industries, Ltd.) was added. After stirring for 2 hours, a coating liquid 1 was obtained. Using this liquid, a glass substrate was subjected to dip coating at a lifting speed of 40 mm / min, and heat treatment was performed at 120 ° C. for 1 hour.
[0059]
When this sample was evaluated by breathing, the coated portion was not clouded. Furthermore, when stored in air (at a temperature of 25 ° C. and a relative humidity of about 55%) for 10 days, the uncoated portion had no anti-fogging property, but the coated portion maintained the anti-fogging property. When the cross section of the sample was observed with an electron microscope, the coating film was porous and had a thickness of about 0.3 μm.
[0060]
Example 2
2 g N2 polyorganosiloxane solution was added to 58 g isopropyl alcohol with stirring. Thereafter, 20 g of Snowtex CM (Nissan Chemical Industries, Ltd.) was added. The mixture was stirred for 2 hours to obtain a coating liquid 2. Using this liquid, a glass substrate was subjected to dip coating at a lifting speed of 40 mm / min, and heat treatment was performed at 120 ° C. for 1 hour.
[0061]
When this sample was evaluated by breathing, the coated portion was not clouded. Further, when stored in air for 10 days, the uncoated portion did not have anti-fogging property, but the coated portion maintained the anti-fogging property. When the cross section of the sample was observed with an electron microscope, the coating film was porous and had a thickness of about 0.3 μm.
[0062]
Example 3
4 g of N1 polyorganosiloxane solution was added to 60 g of isopropyl alcohol with stirring. Then, after adding 15 g of Snowtex CM, 25 g of a photocatalytic sol A-6 solution (component: anatase type titanium oxide, average particle diameter 5 nm, concentration: 6% by weight, manufactured by Taki Chemical Co., Ltd.) was added. After stirring for 2 hours, a coating liquid 3 was obtained. Using this liquid, a glass substrate was dip-coated at a lifting speed of 40 mm / min, and heat-treated at 120 ° C. for 1 hour to obtain a coating sample containing a photocatalyst.
[0063]
When this sample was exposed outdoors (temperature: 10 to 25 ° C., relative humidity: 30 to 70%) for 10 days, the uncoated portion did not have anti-fog properties, but the coated portion did not. Was maintained. When the cross section of the sample was observed with an electron microscope, the coating film was porous and had a thickness of about 0.3 μm.
[0064]
Example 4
1 g of N3 polyorganosiloxane solution was added to 60 g of isopropyl alcohol while stirring. Thereafter, 20 g of silica sol (Nissan Chemical Industries, Ltd., ST-IPA, average particle diameter 10 to 20 nm, concentration 30% by weight) was added. After stirring for 2 hours, a coating liquid 4 was obtained. Using this liquid, a glass substrate was subjected to dip coating at a lifting speed of 30 mm / min, and heat treatment was performed at 120 ° C. for 1 hour.
[0065]
When this sample was evaluated by breathing, the coated portion was not clouded. Further, when stored in air for 10 days, the uncoated portion did not have anti-fogging property, but the coated portion maintained the anti-fogging property. When the cross section of the sample was observed with an electron microscope, the coating film was porous and had a thickness of about 0.25 μm.
[0066]
Example 5
3 g of N2 polyorganosiloxane solution was added to 60 g of isopropyl alcohol while stirring. Thereafter, 20 g of silica sol and 10 g of photocatalytic sol A-6 were added with stirring. After stirring for 2 hours, a coating liquid 5 was obtained. Using this liquid, a glass substrate was subjected to dip coating at a lifting speed of 30 mm / min, and heat treatment was performed at 120 ° C. for 1 hour.
[0067]
When this sample was evaluated by breathing, the coated portion was not clouded. Furthermore, when left outdoors for 10 days, the uncoated portion did not have anti-fogging properties, but the coated portions maintained the anti-fogging properties. When the cross section of the sample was observed with an electron microscope, the coating film was porous and had a thickness of about 0.25 μm.
[0068]
Comparative Example 1
While stirring with 720 parts by weight of ethanol, 140 parts by weight of an ethyl silicate oligomer liquid (Colcoat Co., Ltd., ethyl silicate 40) were added, and 140 parts by weight of a 0.01N hydrochloric acid aqueous solution was slowly added. Then, after reacting at room temperature for one day, a coating solution was obtained. The glass substrate was partially dip coated and heat treated at 150 ° C. for 1 hour.
[0069]
The obtained glass sample was allowed to stand in the air at room temperature for one week. As a result of breathing and visual observation, both the coated portion and the uncoated portion became cloudy. It was found that none of them had antifogging property. This is considered to be due to the fact that the organic substance in the air was adsorbed on the silica film and the hydrophilicity of the surface was reduced.
[0070]
Comparative Example 2
20 g of N3 polyorganosiloxane solution was added to 60 g ethanol with stirring. Thereafter, 20 g of photocatalytic sol A-6 was added. The mixture was stirred for 2 hours to obtain a coating liquid. Using this liquid, a glass substrate was subjected to dip coating at a lifting speed of 30 mm / min, and heat treatment was performed at 120 ° C. for 1 hour. When these samples were stored in air for 10 days, the antifogging property of the surface was lost.
[0071]
【The invention's effect】
As described above, the coating material for an antifogging film of the present invention has a high hydrophilicity on the surface of the coated member and excellent water resistance.
Further, the antifogging coating film of the present invention, since the coating film is porous, it also has water absorption, can maintain high hydrophilicity for a long period of time, even in an environment where humidity changes, the surface does not fog, The formation of a water film is suppressed.
Further, the present invention can provide an optical member having excellent antifogging property using the above antifogging coating film.

Claims (8)

A coating material for forming an antifogging film,
(A) 0.1 to 5 parts by weight of a polyorganosiloxane having a functional group having a nitrogen atom obtained by hydrolysis and condensation polymerization of an organosilicon compound represented by the following general formula (I);

(In the formula, R ¹ is a functional group having a nitrogen atom, m is 1 or 2. R ² is an alkyl group having 1 to 4 carbon atoms.)
(B) 0.1 to 20 parts by weight of oxide fine particles,
(C) An antifogging coating material comprising 50 to 99.8 parts by weight of a hydrophilic organic solvent and forming a porous film. The antifogging coating material according to claim 1, wherein the weight ratio of the polyorganosiloxane to the oxide fine particles is 1/20 to 1/4. The antifogging coating material according to claim 1 or 2, wherein the average particle diameter of the oxide particles is 1 to 300 nm. 4. The protection according to claim 1, further comprising photocatalytic fine particles, wherein the content of the photocatalytic fine particles is 0.5 to 80% by weight with respect to the oxide fine particles. Fogging coating material An antifogging coating film formed by using the antifogging coating material according to claim 1. An anti-fogging optical member comprising the coating film according to claim 5 formed on a substrate. The antifogging optical member according to claim 6, wherein the substrate is a glass substrate, a metal substrate, a plastic substrate, or a ceramic substrate. 8. The antifogging optical member according to claim 6, wherein the base material is a glass mirror, a metal mirror, or a vapor-deposited plastic mirror.