JP2004137137A - Article covered with coating, method of producing the same, and coating solution used in the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an article covered with a coating which contains silicon oxide as a main component and on which fine irregularities serving as a base for ultra water-repellency or ultra hydrophilicity are formed, a method of producing the same, and a coating solution used in the same. <P>SOLUTION: The article is covered with the coating containing silicon oxide as the main component and having fine irregularities on its surface, and it is characterized in that the fine irregularities are constituted of fine projections and columnar projections. Each columnar projection is formed by the local growth of the fine projection in the thickness direction of the coating, and/or by local stacking of a plurality of fine particles constituting the fine projections. <P>COPYRIGHT: (C)2004,JPO

Description

【０１２０】
実施例１〜１１で得られた凹凸を有するシリカ膜被覆ガラス板は、走査型電子顕微鏡を用いてその表面形状を観察したところ、全ての皮膜で微微小突起と柱状突起が形成されていることが確認でき、その表面粗さ（Ｒａ）はいずれも１３ｎｍ以上であった。この結果、皮膜の表面粗さの大きいことが確かめられた。
【０１２１】
さらに、実施例１〜１１で得られた凹凸を有するシリカ膜被覆ガラス板において、水の濡れ性を観察した。その結果、全ての皮膜で水滴がよく濡れて広がっていることを確認した。また、凹凸を有するシリカ膜の親水性を水の接触角で評価した。接触角としては、正確に測定ができないほどで、約５度以下であった。
【０１２２】
また、実施例１〜１１で得られた凹凸を有するシリカ膜被覆ガラス板の透明性を直読ヘイズコンピュータで測定したところ、全ての皮膜のヘイズ率が１．０％以下であり、透明性が高いことが確認された。さらに、皮膜面のムラやガラスエッジ部に液溜まり等の外観上の欠点もなく、非常にきれいな皮膜であることが確認された。また、透過色調、反射色調ともにニュートラルであり、外観上の問題もなかった。
【０１２３】
また本発明における珪素酸化物を主成分とする皮膜被覆ガラス板は、珪素酸化物を主成分とする皮膜を形成していないガラス基板に比して、膜面反射率で約１．６％反射率が低減していた。これは、屈折率１．５２であるソーダライムガラス基板に比して低屈折率である珪素酸化物を主成分とする皮膜と、皮膜表面凹凸の効果によるものと考えられる。
【０１２４】
（応用例：撥水処理）
本発明の応用例として、本発明による凹凸を有するシリカ膜被覆ガラス板にさらに撥水処理を施した。
【０１２５】
この応用例において適用されうる撥水液としては、基材表面に結合する撥水材料を含むものであれば特に限定されない。なお一般的に、撥水材料を溶媒に溶解した溶液として使用する形態が好ましい。また、先に基材表面に形成させるクロロシリル基含有化合物と相性のよい加水分解可能なシリル基を有する化合物が好ましく、その中でも撥水性能の高いフルオロアルキル基を含有したシラン化合物がさらに好ましい。
【０１２６】
前記フルオロアルキル基含有シラン化合物は、フルオロアルキル基を含有し、かつアルコキシ基、アシロキシ基、または塩素基を含有するシラン化合物であり、例えば、ＣＦ_３（ＣＦ_２）_７（ＣＨ_２）_２Ｓｉ（ＯＣＨ_３）_３、ＣＦ_３（ＣＦ_２）_５（ＣＨ_２）_２Ｓｉ（ＯＣＨ_３）_３、ＣＦ_３（ＣＦ_２）_７（ＣＨ_２）_２ＳｉＣｌ_３、ＣＦ_３（ＣＦ_２）_５（ＣＨ_２）_２ＳｉＣｌ_３、等が挙げられる。
【０１２７】
これらの中から、単独でまたは複数を組み合わせて使用することができるが、特に反応性と撥水性の高い、ＣＦ_３（ＣＦ_２）_７（ＣＨ_２）_２ＳｉＣｌ_３が最も好ましい。
【０１２８】
撥水材料を溶解する溶媒は、撥水材料が溶解すれば特に限定はないが、先に基材表面に形成させるクロロシリル基含有化合物が、シリコーン系を含む溶媒に溶解して塗布されている。このため、その後に塗布する撥水剤も、同系統である非水系溶媒が好ましい。
【０１２９】
この非水系溶媒としては、パラフィン系炭化水素やフロン系、シリコーン油を主成分とする溶媒等が挙げられるが、これらの中でも先に基材表面に形成させるクロロシリル基含有化合物を溶解させる溶媒と同じシリコーン油を主成分とする溶媒が好ましい。
【０１３０】
前記撥水液を塗布する方法は、先に形成した凹凸を有するシリカ膜の表面形状を壊さない方法が必要であり、具体的には、先に形成させるクロロシリル基含有化合物と同じ吸着させる方法が好ましい。
【０１３１】
撥水液を吸着させるためには、撥水液を塗布した後、少なくとも０．１秒間撥水液が基材表面を濡らしている必要がある。
【０１３２】
撥水液は、先に凹凸を有するシリカ膜を形成させたクロロシリル基含有化合物と異なり、撥水材料が一層だけ結合すればよいので、撥水液を濡らす時間は、クロロシリル基含有化合物が基材表面に自然吸着積層させる時間より、短くてよい。
【０１３３】
しかし０．１秒未満であると、撥水材料が十分に吸着されないため、十分な撥水性が発現できなくなる。
【０１３４】
このような吸着を可能にする方法としては、フローコーティング法、ディップコーティング法、カーテンコーティング法、スピンコーティング法、スプレーコーティング法、バーコーティング法、浸漬吸着法などが挙げられる。効率よく塗布するためには、このうちフローコーティング法やスプレーコーティング法が好ましい。
【０１３５】
（応用例１〜１１）
まず、ヘプタデカフルオロデシルトリクロロシラン（ＣＦ_３（ＣＦ_２）_７（ＣＨ_２）_２ＳｉＣｌ_３）２ｇを、デカメチルシクロペンタシロキサン９８ｇに撹拌しながら添加し、撥水処理剤を得た。
【０１３６】
この撥水処理剤を、上述した実施例１〜１１の凹凸を有するシリカ膜被覆ガラス板の表面上に、相対湿度３０％、室温下でフローコート法にて塗布し、１分間撥水処理剤でガラス基板表面を濡らしたまま静置させ、その後、エタノールで表面の撥水処理剤を完全に洗い流し、自然乾燥させ、それぞれ応用例１〜１１である撥水処理ガラス板を得た。
【０１３７】
得られた撥水処理ガラス板について、まずその撥水性能を水の接触角で評価した。接触角計（「ＣＡ−ＤＴ」、協和界面科学（株）製）を用い、２ｍｇの質量の水滴をガラス板表面に滴下して、静的接触角を測定した。なおこの接触角の値が大きいほど、静的な撥水性が優れていることを表している。
【０１３８】
次に、得られた撥水処理ガラス板について、その膜の透明性をヘイズ率で評価した。ヘイズ率は、直読ヘイズコンピュータ（「ＨＧＭ−２ＤＭ」、スガ試験機（株）製）を用いて測定した。なおこのヘイズ率が小さいほど、皮膜の透明性が高いことを表している。
【０１３９】
さらに、得られた撥水処理ガラス板について、その膜の耐摩耗性を評価した。耐摩耗性試験は、往復摩耗試験機（新東科学（株）製）に乾布を取り付けて、荷重１２５ｇ／ｃｍ^２の条件で、撥水処理ガラスを１００回往復摺動させ、その後に、撥水処理ガラスの水の接触角を、試験前の測定と同じ条件で測定した。
【０１４０】
【表２】

【０１４１】
応用例１〜１１で得られた撥水処理ガラス板は、１５０度以上の初期接触角を示し、超撥水性を有することが確認できた。
【０１４２】
なお耐摩耗性試験後の接触角は、それぞれ１００度以上であり、超撥水性は示さないものの、十分通常の撥水性は示し、優れた耐擦傷性を有することが確かめられた。
【０１４３】
さらにヘイズ率は、実施例１〜１１で得られた凹凸を有するシリカ膜被覆ガラス板と殆ど変化なく、全ての皮膜のヘイズ率が１．０％以下であり、透明性が高いことが確認された。
【０１４４】
（比較例１）
実施例１と同様に調整した凹凸を形成させるシリカ膜の被覆用溶液を、洗浄したガラス基板の表面上に、相対湿度３０％、室温下でフローコート法にて塗布し、０．５秒間この溶液でガラス基板表面を濡らしたまま静置させた。その後、エタノールでガラス基板表面の凹凸を形成させるシリカ膜の被覆用溶液を完全に洗い流し、自然乾燥させ、凹凸を有するシリカ膜被覆ガラス板を得た。この凹凸を有するシリカ膜被覆ガラス板の表面上に、応用例１〜１１と同様に撥水処理を行い、撥水処理ガラス板を得た。
【０１４５】
得られた撥水処理ガラス板を応用例１〜１１と同様に評価した結果、初期接触角が１２０度であり、応用例に比して撥水性能に劣ることが確認された。
【０１４６】
（比較例２）
テトラクロロシラン（ＳｉＣｌ_４：信越シリコーン製）４．０ｇを、デカメチルシクロペンタシロキサン（ＫＦ−９９５：信越シリコーン製）９６．０ｇに撹拌しながら添加し、凹凸を形成させるシリカ膜の被覆用溶液を得た。
【０１４７】
この凹凸を形成させるシリカ膜の被覆用溶液を、洗浄したガラス基板の表面上に、相対湿度３０％、室温下でフローコート法にて塗布し、５分間この溶液でガラス基板表面を濡らしたまま静置させた。その後、エタノールでガラス基板表面の被覆用溶液を、完全に洗い流して自然乾燥させ、凹凸を有するシリカ膜被覆ガラス板を得た。この凹凸を有するシリカ膜被覆ガラス板の表面上に、応用例１〜１１と同様に撥水処理を行い、撥水処理ガラス板を得た。
【０１４８】
得られた撥水処理ガラス板を応用例１〜１１と同様に評価した結果、初期接触角が１２３度であり、応用例に比して撥水性能に劣ることが確認された。また、皮膜は部分的に白い粉状のものが観察され、ヘイズ率も３．８％であり、透明性も劣っていた。
【０１４９】
（比較例３）
実施例１において、デカメチルシクロペンタシロキサンを、イソパラフィン系炭化水素（アイソゾール３００：日本石油化学（株）製）に変更した以外は、実施例１と同様にして凹凸を有するシリカ膜被覆ガラス板を得た。この凹凸を有するシリカ膜被覆ガラス板の表面上に、応用例１〜１１と同様に撥水処理を行い、撥水処理ガラス板を得た。
【０１５０】
得られた撥水処理ガラス板を応用例１〜１１と同様に評価した結果、初期接触角が９１度であり、応用例に比して撥水性能に劣ることが確認された。
【０１５１】
（比較例４）
実施例１と同様に調整した凹凸を形成させるシリカ膜の被覆用溶液を、洗浄したガラス基板の表面上に塗布する時の環境を相対湿度１０％に変えた以外は、実施例１と同様にして凹凸を有するシリカ膜被覆ガラス板を得た。この凹凸を有するシリカ膜被覆ガラス板の表面上に、応用例１〜１１と同様に撥水処理を行い、撥水処理ガラス板を得た。
【０１５２】
得られた撥水処理ガラス板を応用例１〜１１と同様に評価した結果、初期接触角が１１４度であり、応用例に比して撥水性能に劣ることが確認された。
【０１５３】
（応用例：防汚処理）
（応用例１２）
撥水処理の応用例で用いたヘプタデカフルオロデシルトリクロロシランの代わりに、［メトキシ（ポリエチレンオキシ）プロピル］トリメトキシシラン（チッソ（株）製、含有率９０％、分子量４６０〜５９０、エチレンオキシド単位数６〜９）を用いた以外は応用例１と同様にして、防汚機能付き親水性膜を得た。
【０１５４】
得られた防汚機能付き親水性膜において、水の濡れ性を観察した。その結果、水滴がよく濡れて広がっていることを確認した。また、親水性を水の接触角で評価した。接触角としては、正確に測定ができないほどで、約５度以下であった。これは、防汚膜自体の接触角も低く、先に形成させた凹凸を有するシリカ膜の凹凸の効果と相まって、優れた親水性を示すもとのと推定できた。
【０１５５】
次に、この防汚機能付き親水性膜の防汚性能を評価した。この防汚機能付き親水性膜に市販のオリーブ油を数滴垂らし、室温で３０分間放置した後、エタノールで洗い流したところ、オリーブ油が完全に除去され、防汚機能のあることが確認された。
【０１５６】
（比較例５）
実施例１の凹凸を有するシリカ膜被覆ガラス板に応用例１２と同様に防汚性能を評価した。その結果、オリーブ油が一部残っており、応用例１２に比して防汚性能に劣ることが確認できた。
【０１５７】
【発明の効果】
以上説明してきたように、本発明による珪素酸化物を主成分とする皮膜は、その表面に微小な粒子状突起を形成させ、さらにその一部を柱状に成長させた微小凹凸を有することを特徴としている。このため、優れた親水性や撥水性の礎となる皮膜である。
【０１５８】
またこの珪素酸化物を主成分とする皮膜では、微小凹凸を形成する微小突起と柱状突起の直径を２００ｎｍ以下、平均５０ｎｍ程度としている。このため、親水性や撥水性の礎となる十分な凹凸を有しながら、しかも皮膜の透明性が高いという効果を奏する。
【０１５９】
さらにこの珪素酸化物を主成分とする皮膜では、皮膜の表面に微小な粒子状突起を形成させ、さらにその一部を柱状に成長させている。このため、撥水処理された本発明による珪素酸化物を主成分とする皮膜は、例え表面が摩耗されることにより超撥水状態ではなくなったとしても、通常の撥水性は十分に有しているので、耐摩耗性に優れるという効果を奏する。
【０１６０】
またこの珪素酸化物を主成分とする皮膜では、自然に微小な粒子状突起が形成され、さらにその一部が柱状に成長するため、その外観品質がよいという効果を奏する。
【０１６１】
また本発明による方法は、クロロシリル基含有化合物をシリコーン油を主成分とする溶媒に溶解した溶液を基材表面に塗布するだけであるので、本質的に焼成工程を必要とせず、優れた生産性で珪素酸化物を主成分とする皮膜被覆物品を製造することができる。
【０１６２】
さらに本発明における皮膜は、屈折率と表面凹凸の効果により、低反射性も示すという効果を奏する。
【図面の簡単な説明】
【図１】実施例１で得られた珪素酸化物を主成分とする皮膜のＳＥＭによる観察写真である。
【図２】実施例９で得られた珪素酸化物を主成分とする皮膜のＳＥＭによる観察写真である。
【図３】微小凹凸形成のメカニズムを説明する模式図である。
【符号の説明】
１：（ガラス）基体
２：塗布された溶液
３：核
４：オリゴマー
５：クロロシリル基含有化合物
６：（析出前の）オリゴマー
７：柱状突起
８：粒子状突起[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coated article coated with a coating mainly composed of silicon oxide having fine irregularities, a method for producing the same, and a coating solution used for the same. In particular, the present invention is useful for a coating mainly composed of silicon oxide formed by a sol-gel method.
[0002]
[Prior art]
In order to impart water repellency or hydrophilicity to the surface of a glass plate or other base material, it is preferable to form irregularities on the surface.
[0003]
Generally, the wettability of a solid surface is affected by the surface roughness. That is, when the solid surface is hydrophilic, the hydrophilicity of the rough surface is improved, and when the solid surface is hydrophobic, the water repellency of the rough surface is improved. This phenomenon appears remarkably when the surface has a fractal structure, and as a result, the fractal surface can be a surface called super water repellent or super hydrophilic depending on the material.
[0004]
Note that a water repellent state in which the contact angle of water exceeds 150 degrees is generally called super water repellency. A state of hydrophilicity that makes it difficult to measure the contact angle of water is called superhydrophilicity.
[0005]
For example, (1) Japanese Patent Application Laid-Open No. 6-25449 discloses a method in which fine projections are formed on the surface of a plastic film by plasma treatment, and then a fluorine compound is chemically adsorbed.
[0006]
(2) JP-A-11-286784 discloses that a treatment liquid containing a polycondensate of a metal alkoxide, metal oxide fine particles, and a silane compound having a fluoroalkyl group is applied to a glass surface and dried, so that the glass surface is dried. A method for forming a fine uneven structure is disclosed.
[0007]
(3) Japanese Patent Application Laid-Open No. 2000-144116 discloses a water-repellent film that forms irregularities on the surface by applying a coating solution containing a polycondensate of trialkoxysilane onto a substrate and performing a heat treatment.
[0008]
(4) Japanese Patent Application Laid-Open No. 2001-17907 discloses a method in which a solution containing an aluminum compound is applied to a substrate to form a film, and the film is immersed in warm water to form fine irregularities on the surface.
[0009]
(5) Japanese Patent Application Laid-Open No. 2001-207123 discloses a solution in which a metal alkoxide and a substance having a property of decomposing, burning, and sublimating in a solvent at a temperature of from room temperature to 700 ° C. are added to the solvent. Is applied to a base material and heat-treated to form a microporous layer having an average pore diameter of 100 nm to 2 μm.
[0010]
[Patent Document 1]
JP-A-6-25449
[Patent Document 2]
JP-A-11-286784
[Patent Document 3]
JP 2000-144116 A
[Patent Document 4]
JP 2001-17907 A
[Patent Document 5]
JP 2001-207123 A
[0011]
[Problems to be solved by the invention]
However, in the methods disclosed in the above (1), (2) and (5), the film thickness and / or unevenness is large. For this reason, the transmitted light is scattered and the haze value is increased, so that the transparency of the film is reduced.
[0012]
In the techniques disclosed in (3) and (5), it is necessary to apply a coating solution to a substrate and then heat-treat the substrate at a high temperature. Therefore, the substrate is limited to a material having high heat resistance. In addition, heat treatment is required.
[0013]
In the method disclosed in (1), since the unevenness is formed by the plasma processing, a processing apparatus for this is required.
[0014]
In the method disclosed in (4), since the unevenness is formed by immersion in hot water, a hot water supply device is required.
[0015]
Furthermore, according to the techniques disclosed in (2), (3), (4) and (5), since a wet coating film is formed by dip coating or the like and then dried, unevenness occurs at the glass edge and the film surface. And the appearance quality of the coating deteriorates.
[0016]
Furthermore, in the techniques disclosed in (1), (2), (3), (4) and (5), the unevenness of the film surface has an irregular fractal structure, so that the film has high wear resistance. The sex gets worse.
[0017]
For example, in a substrate exhibiting hydrophobicity, the more the roughness is formed on the surface and the greater the roughness of the surface, the larger the contact angle of water. When the contact angle exceeds 150 degrees, the water droplets exhibit super water repellency such that it is difficult for water droplets to stay on the surface. It is said that in order to exhibit such super water repellency, a shape capable of retaining a large amount of air between surface irregularities and water droplets is required.
[0018]
However, if there are large irregularities on the surface, for example, several hundred nm or more, light is scattered, and in the case of a transparent substrate, there is a problem that haze is generated and transparency is impaired.
[0019]
In the conventional super-water-repellent surface, projections on the surface are formed in a complicated fractal shape. Each of the protrusions is brittle and breaks even with a weak force. For this reason, there is also a problem that water repellency is immediately lost due to friction or the like.
[0020]
Accordingly, the present invention provides a film-coated article coated with a film containing silicon oxide as a main component, which has a non-conventional uneven shape, as a fine unevenness serving as a foundation for superhydrophobicity or superhydrophilicity, a method for producing the same, And a coating solution used for the same.
Further, the present invention provides a method for producing a film containing silicon oxide as a main component, which does not essentially require a firing step and has excellent productivity.
[0021]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention provides a camera as described in claim 1 as:
An article coated with a coating mainly composed of silicon oxide having fine irregularities on its surface,
The minute unevenness is a film-coated article characterized by being constituted by minute protrusions and columnar protrusions.
[0022]
As the invention according to claim 2,
The columnar protrusions are formed by locally growing the fine protrusions in the thickness direction of the coating, and / or by locally laminating a plurality of fine particles constituting the fine protrusions. The coated article according to claim 1.
[0023]
As the invention according to claim 3,
3. The film-coated article according to claim 1, wherein a relational expression of 2Dc ≦ H is satisfied, where Dc is the diameter of the columnar protrusion and H is the height.
[0024]
As the invention according to claim 4,
The coated article according to claim 3, wherein the Dc is 10 to 200 nm and at least H is 50 nm.
[0025]
As the invention according to claim 5,
The film-coated article according to claim 1, wherein the fine projection has a diameter Dp of Dp = 5 to 200 nm.
[0026]
As the invention according to claim 6,
The coating-coated article according to any one of claims 1 to 5, wherein the surface roughness of the coating is at least 10 nm in arithmetic average roughness (Ra), and the haze ratio of the coating is 1% or less.
[0027]
As the invention according to claim 7,
The film-coated article according to any one of claims 1 to 6, wherein a contact angle of water measured by dropping 1 mg of a water droplet on the surface of the film is 5 degrees or less.
[0028]
As the invention according to claim 8,
The coated substrate according to any one of claims 1 to 7, wherein the substrate is any one of a glass plate, a resin plate, and a resin film.
[0029]
According to the ninth aspect of the present invention,
A method for producing a film-coated article in which a substrate and a film containing silicon oxide as a main component are formed on the substrate surface,
A step of applying a solution containing a silicon-containing raw material on the surface of the base material,
Forming microprojections containing silicon supplied from the silicon-containing raw material on the surface,
Forming a columnar protrusion by locally growing the fine protrusions locally in the thickness direction of the film and / or locally laminating a plurality of fine particles constituting the fine protrusions. A method for producing a film-coated article.
[0030]
As the invention according to claim 10,
The method for producing a film-coated article according to claim 9, wherein the step of forming the columnar projections keeps the substrate surface wet with the solution for a time sufficient for the columnar projections to grow.
[0031]
As the invention according to claim 11,
The method according to claim 10, wherein the time is at least one second.
[0032]
As the invention according to claim 12,
The method according to claim 9, wherein the locally grown columnar protrusion is formed by directly depositing a silicon-containing raw material dissolved in the solution on the surface of the base material. .
[0033]
As the invention according to claim 13,
The coating according to claim 9, wherein the stacked columnar projections are formed by depositing silicon-containing raw materials dissolved in the solution as fine particles in the solution and depositing the fine particles on the surface of the base material. This is a method for producing a coated article.
[0034]
As the invention according to claim 14,
The method according to claim 9, wherein the solution is obtained by dissolving a chlorosilyl group-containing compound in a solvent containing silicone oil as a main component.
[0035]
As the invention according to claim 15,
The method for producing a film-coated article according to claim 14, wherein the concentration of the chlorosilyl group-containing compound is 0.01 to 10% by mass.
[0036]
As the invention according to claim 16,
The method according to claim 14, wherein the chlorosilyl group-containing compound is tetrachlorosilane.
[0037]
As the invention according to claim 17,
The method for producing a film-coated article according to any one of claims 14 to 16, wherein the solvent containing silicone oil as a main component is dimethyl silicone oil.
[0038]
As the invention according to claim 18,
The method for producing a film-coated article according to claim 9, wherein the coating step and the step of forming the columnar projections are performed under environmental conditions of a temperature of 10 to 40C and a relative humidity (RH) of 15 to 60%. .
[0039]
As the invention according to claim 19,
The method according to any one of claims 9 to 18, wherein the substrate is any one of a glass plate, a resin plate, and a resin film.
[0040]
As the invention according to claim 20,
The method according to any one of claims 9 to 19, wherein the base material is a transparent plate for a vehicle mounted on a vehicle.
[0041]
As the invention according to claim 21,
A coating solution for forming a film, characterized in that a chlorosilyl group-containing compound is dissolved in a solvent containing silicone oil as a main component.
[0042]
As the invention according to claim 22,
22. The coating solution for forming a film according to claim 21, wherein the water content in the solvent containing the silicone oil as a main component is 0.03% by mass or less.
[0043]
As the invention according to claim 23,
22. The coating solution for forming a film according to claim 21, wherein the concentration of the chlorosilyl group-containing compound is 0.01 to 10% by mass.
[0044]
The film in the film-coated article of the present invention has fine irregularities, and the irregularities are basically fine projections (particulate projections) and have a height higher than the particulate projections as measured from the surface of the substrate. And columnar projections.
[0045]
In the present invention, fine particulate projections are first formed on the surface of a film containing silicon oxide, for example, silica as a main component. Further, the columnar projections are formed by laminating a plurality of particles constituting the particulate projections so as to overlap each other, or by locally growing the particulate projections in the thickness direction of the film. Has formed. By forming such protrusions, the surface roughness can be increased, and air can be held between the columnar protrusions and the minute protrusions and between the columnar protrusions.
[0046]
The columnar projection is, for example, an integral projection, that is, a projection formed by locally growing fine particles in the thickness direction of the film. In this case, if the diameter of the columnar projection is Dc and the height is H, 2Dc ≦ H, preferably 3Dc ≦ H is satisfied. Here, Dc and H may use values measured by SEM. Dc is preferably from 10 nm to 200 nm. The preferred range of H depends on the value of Dc, but is usually 50 nm or more. These numerical values are determined based on the results of observing and measuring the surface shape of the film with a scanning electron microscope and the hydrophilicity and water repellency of the film, as described later.
[0047]
The columnar protrusion may be configured by overlapping fine particles. The number and form of the lamination of the fine particles are not particularly limited, but protrusions formed by laminating two or more fine particles in the thickness direction of the coating project from the surroundings. It is preferable that a linked body in the thickness direction of the film of three or more fine particles surrounded by fine protrusions corresponding to the height of the fine particles forms a columnar protrusion.
In the film of the present invention, an integral projection and a projection formed by laminating fine particles may be mixed as columnar projections.
[0048]
In this specification, the term “locally grown” is used to mean that the microprojections have grown to twice or more, preferably three times or more the average height. Further, the term “locally” is used to mean that it occupies a predetermined area of the film surface. As will be described later, this more preferable ratio of the predetermined area can be alternatively expressed by compatibility of two opposing characteristics (both a surface roughness equal to or more than a predetermined value and a haze ratio equal to or less than a predetermined value). Further, the term "main component" is used as a term meaning a component occupying 50% by mass or more.
[0049]
Further, in the present invention, when a force is applied to the surface of the film, even if the columnar projection is broken, the minute projection is structured to be hardly damaged. For this reason, the film according to the present invention is superior in durability (abrasion resistance) in that normal water repellency is maintained even if the super water repellency is lost, as compared with conventional super water repellent articles. .
[0050]
As described above, there are two types of columnar projections in the present invention. One type is formed by locally growing from the film surface to form an integrally formed shape, and the other is formed by stacking fine projections. Take it. These differences depend on the film formation conditions. For example, when the concentration of the chlorosilyl group-containing compound is high, the particles forming the fine projections are likely to have a shape in which they overlap. However, there is no difference in the super-water repellency, super-hydrophilicity, and durability of either shape, and thus there is no particular limitation.
[0051]
In the present invention, the particulate microprojections have a diameter Dp of Dp = 5 to 200 nm, and the columnar projections have a diameter Dc and a height H of 2Dc ≦ H, and Dc = 10 to 200 nm. , At least H is preferably 50 nm. More preferably, the diameter Dp of the microprojections is 20 to 100 nm on average, and the diameter Dc of the columnar projections is 20 to 100 nm on average. With such a configuration, the haze ratio can be kept low. For this reason, it is easy to achieve both the microscopic uneven structure serving as a foundation for superhydrophobicity and superhydrophilicity and the transparency of the film. If the diameter of the projection exceeds this, the transparency of the film containing silicon oxide as a main component may be impaired.
[0052]
On the other hand, if the height H of the columnar projections is less than 50 nm, the structure will not be a fine uneven structure that exhibits superhydrophobicity or superhydrophilicity.
[0053]
In addition, since the columnar projections in the present invention are naturally grown, they are not necessarily formed only in the vertical direction to the substrate surface, but are bent from the middle in the vertical direction or grown obliquely from the beginning. However, there is no problem with these shapes. In these shapes, when the height in the vertical direction is H, and the average diameter of the portion corresponding to the outermost surface is D, there is no difference in water repellency and durability as long as the height is in the above range, so that it is particularly limited. is not.
[0054]
Further, in the prior art, a method of once forming a smooth surface and then forming irregularities on the surface by plasma, hot water treatment, high-temperature baking, or the like is often used, but these methods require high equipment costs. In addition, there is a limitation on the base material on which the irregularities are formed. For example, it is practically impossible to apply these methods to a glass sheet attached to an automobile.
[0055]
On the other hand, according to the present invention, since the coating solution may be applied to the surface of the substrate and the solution may be dried, there is no need to select the substrate or its state.
[0056]
Further, the surface roughness of the coating mainly composed of silicon oxide according to the present invention is preferably at least 10 nm in arithmetic average roughness (Ra), and the haze ratio of the coating is preferably 1.0% or less. More preferably, it is not more than 0.5%. As described above, the film containing silicon oxide as the main component according to the present invention has excellent transparency.
[0057]
As the surface roughness increases, the water repellency and hydrophilicity can be improved. On the other hand, as for the uneven surface formed by the conventional technique, as the surface roughness increases, the haze ratio of the coating increases, and it is difficult to achieve both water repellency and hydrophilic performance and transparency.
[0058]
The upper limit of the surface roughness of the film is not particularly limited as long as the haze ratio is within the range of 1.0% or less.
[0059]
However, the coating according to the present invention containing silicon oxide as a main component has a large surface roughness due to the effect of columnar projections on the surface, and has a fine uneven structure capable of retaining air therebetween. Since the film containing silicon oxide as the main component is basically hydrophilic, the film containing silicon oxide as the main component according to the present invention exhibits superhydrophilicity in combination with the minute uneven structure. Further, the film containing silicon oxide as a main component can be used as a base film of a functional film exhibiting super water repellency and antifouling property.
[0060]
This coating contains silicon oxide as a main component, and may further contain other components such as titanium oxide, aluminum oxide, and zirconium oxide.
[0061]
Hereinafter, a method for producing a film containing silicon oxide as a main component will be described by taking as an example a case where a solution obtained by dissolving a chlorosilyl group-containing compound in a solvent containing silicone oil as a main component is applied to the surface of a substrate (FIG. 3). reference).
[0062]
First, in this solution, when the chlorosilyl group-containing compound is added to a solvent containing silicone oil as a main component, the chlorosilyl group-containing compound is dissolved in the solvent while the chloro group is retained.
[0063]
When this coating solution 2 is applied to the surface of the substrate 1, the chlorosilyl group-containing compound is bonded to the hydrophilic group (-OH group) on the substrate surface during the application. Further, the chlorosilyl group-containing compound is bound to the surface of the substrate while the condensation polymerization reaction proceeds from the hydrolysis by the moisture in the air and the water adsorbed on the surface of the substrate. At this time, sparse particle nuclei 3 are formed on the substrate surface (FIG. 3A).
[0064]
If the surface of the base material is wetted with the coating solution as it is, the chlorosilyl group-containing compound undergoes condensation polymerization reaction from hydrolysis with moisture in the air, and oligomer 4 of silicon oxide is generated. When the oligomer grows to a size that is difficult to dissolve in the solvent, it starts to precipitate from the solvent, the deposited oligomer 4 deposits on the glass surface, and the projection grows (FIG. 3B).
[0065]
When silanol (Si-OH group) is formed on the surface of the nucleus 3 formed on the substrate surface, the chlorosilyl group-containing compound 5 is bonded. Also, the oligomer 6 before the precipitation is bonded to the Si—Cl group or Si—OH group on the uneven surface, and the projection grows from the substrate side (FIG. 3C).
[0066]
Through the deposition process shown in FIGS. 3B and 3C, the columnar projections 7 are formed on the surface of the substrate 1 together with the particulate projections 8 (FIG. 3D).
[0067]
Since the growth of the projections described above tends to occur at protruding portions on the surface of the substrate, it is considered that the nuclei are concentrated on the nuclei formed immediately after the application, and the nuclei grow into columnar projections.
[0068]
The difference between the shape formed integrally from the substrate surface and the shape formed by overlapping the particles is that the amount of the deposited oligomer and the dissolved silicon oxide raw material are directly It is considered that this is due to the influence of the ratio of the amount deposited on the surface, the density of nuclei formed immediately after coating, and the like.
[0069]
As described above, the formation of the film containing silicon oxide as a main component in the present invention is strongly affected by the formation of the silica oligomer, the reaction between the silicon oxide raw material and the substrate, the solubility of the silica oligomer in the solvent, and the like. it is conceivable that.
[0070]
The silicon oxide raw material in the present invention, as described above, forms a silicon oxide-containing oligomer, and is not particularly limited as long as it has high reactivity with the base material and is soluble in a solvent. However, a chlorosilyl group-containing compound is preferably used because the chloro group shows a very strong reaction with water or a hydrophilic group (—OH group) on the surface of the substrate.
[0071]
The solvent in the present invention is preferably one that does not suppress the reactivity of the above-described silicon oxide raw material (solute) and that hardly dissolves the formed silica oligomer. For example, an aqueous solvent is not preferable because a chlorosilyl group-containing compound reacts with water to form an OH group having low reactivity. Examples of the solvent capable of retaining a highly reactive chloro group as it is include non-aqueous solvents, and among them, a solvent containing a silicone oil as a main component is preferably used.
[0072]
For example, as a non-aqueous solvent which is not a solvent containing silicone oil as a main component, a chlorosilyl group-containing compound was dissolved in an isoparaffinic hydrocarbon and applied to the surface of a substrate. Then, although the obtained film had some irregularities, it did not form up to the columnar projections as in the present invention. For this reason, this film did not show superhydrophilicity. This is thought to be due to the difference in water absorption among non-aqueous solvents.
[0073]
Next, the influence of the reactivity of the silicon oxide raw material was examined. The step of applying a coating solution obtained by dissolving a chlorosilyl group-containing compound in a solvent containing silicone oil as a main component was performed in a low humidity environment, for example, at a temperature of 20 ° C. and a relative humidity (RH) of 10%.
[0074]
As a result, although minute projections were formed, columnar projections were not formed. This is presumably because the reaction of the chlorosilyl group-containing compound proceeds with moisture in the air, and the reaction hardly proceeds in a low humidity environment where the amount of moisture is small, and as a result, the columnar projection did not grow.
[0075]
Conversely, if this coating solution is applied to the surface of a substrate in a high humidity environment, for example, at a temperature of 30 ° C. and a relative humidity (RH) of 70%, the reaction proceeds too quickly, and large projections that cause the film to whiten are formed. Been formed.
[0076]
Further, after water was previously absorbed in a solvent containing silicone oil as a main component, a solution in which a chlorosilyl group-containing compound was dissolved was applied to the surface of the substrate. As a result, although the obtained film had fine projections formed, no columnar projections were formed.
[0077]
The water content of the solvent at this time was measured to be 0.035% by mass, and it was found that the water content in the solvent containing silicone oil as a main component in the present invention was preferably 0.03% by mass or less. Was. This is considered to be due to the fact that the chlorosilyl group-containing compound was hydrolyzed and polycondensed by the water in the solvent, and oligomerization proceeded in the solution.
[0078]
In other words, when the chlorosilyl group-containing compound is dissolved in a state in which the water content of the solvent containing silicone oil as a main component is low, and this solution is applied to the surface of the substrate, during the application and while the solution is wet on the surface of the substrate, It is considered that this solution appropriately absorbs the moisture in the air, whereby the oligomerization proceeds appropriately, and both the particulate minute projections and the columnar projections are formed.
[0079]
In order to form particulate projections and columnar projections on the surface of the substrate, usually after coating the solution on the surface of the substrate, at least the surface of the substrate must be wet with the solution for 1 second, and 10 seconds or more, In particular, it is more preferable to be wet for 1 minute or more.
[0080]
If the wetting time is short, the chlorosilyl group-containing compound is not sufficiently adsorbed on the substrate surface, so that a film having a fine uneven structure serving as a foundation for superhydrophobicity and superhydrophilicity cannot be obtained.
[0081]
For the purpose of replenishing the chlorosilyl group-containing compound that is naturally adsorbed and laminated on the surface of the base material, it is more preferable that the solution is once applied to the surface of the base material and wetted, and then the same solution is applied again. When the solution is supplied in two or more portions, the next solution must be completely dried before the first solution is completely dried so that the time during which the substrate is wet with the solution is at least a predetermined time, for example, one second or more. A solution may be provided.
[0082]
The concentration of the chlorosilyl group-containing compound varies depending on the coating method, but is preferably 0.01 to 10% by mass, more preferably 0.1% to 3% by mass.
[0083]
If the concentration of the chlorosilyl group-containing compound is too high, the film becomes thick and becomes white powder, which is not preferable. On the other hand, if the concentration of the chlorosilyl group-containing compound is too low, a film having a sufficient thickness cannot be obtained. For this reason, it is not preferable because it is not possible to form a fine uneven structure serving as a foundation for superhydrophobicity or superhydrophilicity.
[0084]
The coating method in the present invention requires that the coating solution is uniformly wetted on the surface of the substrate, and after coating, there is no mechanical contact with the surface of the substrate, and the coating solution wets the surface of the substrate. It is preferable to keep it in a state of being held.
[0085]
Specific examples of the method include a flow coating method, a dip coating method, a curtain coating method, a spin coating method, a spray coating method, a bar coating method, and an immersion adsorption method. For efficient application, a flow coating method and a spray coating method are preferable.
[0086]
The chlorosilyl group-containing compound used in the present invention refers to a chlorosilyl group (-SiCl _n X _3-n Wherein n is 1, 2, or 3, and X is hydrogen or a compound having at least one alkyl, alkoxy, or acyloxy group having 1 to 10 carbon atoms, respectively, in the molecule. .
[0087]
Among them, a compound having at least two chlorines is preferable. _n H _{2n + 2} (Where n is an integer of 1 to 5) chlorosilanes in which at least two hydrogens in the above are substituted with chlorine, and other hydrogens are optionally substituted with the above-mentioned alkyl group, alkoxy group, or acyloxy group, and chlorosilanes thereof. Partially hydrolysates and polycondensates thereof are preferred.
[0088]
For example, tetrachlorosilane SiCl ₄ , Trichlorosilane SiHCl ₃ , Trichloromonomethylsilane SiCH ₃ Cl ₃ , Dichlorosilane SiH ₂ Cl ₂ , And Cl- (SiCl ₂ O) _n -SiCl ₃ (N is an integer of 1 to 10). Among these, a compound having a chlorosilyl group can be used alone or in combination of two or more, and tetrachlorosilane is the most preferable compound.
[0089]
The solvent containing silicone oil as a main component in the present invention is preferably composed of a chain or / and cyclic dimethyl silicone oil. For example, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and the like can be given. Also, from these, they can be used alone or in combination.
[0090]
The environment of the coating step in the present invention is preferably a temperature of 10 to 40 ° C. and a relative humidity (RH) of 15 to 60%, and a temperature of 15 to 25 ° C. and a relative humidity (RH) of 20 to 40%. 40% is more preferred. When the temperature and the humidity are too low, the columnar projections are not formed as described above. As described above, at least the temperature and the humidity greatly affect the state of the unevenness of the film, and should be controlled.
[0091]
On the other hand, if the humidity is too high, the size of the projections increases, so that the transparency of the formed film containing silicon oxide as a main component is impaired. On the other hand, if the temperature is too high, the solution applied to the surface of the substrate dries quickly, and it becomes difficult to maintain the state in which the surface of the substrate is wet with the solution.
[0092]
The substrate used in the present invention is not particularly limited, but those having a hydrophilic group on the surface of the substrate are preferably used. Specific examples include glass, ceramics, plastics, and metals.
[0093]
If the surface of these substrates has few hydrophilic groups, the surface may be treated in advance with oxygen-containing plasma or corona atmosphere to make them hydrophilic. Alternatively, the solution according to the present invention may be applied after the surface of the substrate is irradiated with ultraviolet rays having a wavelength of about 200 to 300 nm in an atmosphere containing oxygen to perform a hydrophilic treatment.
[0094]
Further, the film of the present invention containing silicon oxide as a main component is characterized by having low reflectivity due to its low refractive index and surface unevenness.
[0095]
BEST MODE FOR CARRYING OUT THE INVENTION
As used hereinafter, "silica" refers to complete SiO ₂ Does not exist in the state described above, but means silicon oxide.
[0096]
(Example 1)
Tetrachlorosilane (SiCl ₄ : Shin-Etsu Silicone) (0.5 g) was added to 99.5 g of decamethylcyclopentasiloxane (KF-995: Shin-Etsu Silicone) with stirring to obtain a silica film coating solution for forming irregularities. As the glass substrate, a soda lime glass plate by a float method was used.
[0097]
The silica film coating solution for forming the irregularities is applied on the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and the surface of the glass substrate is wetted with the solution for 1 minute. It was left still. Further, the same solution was again applied thereon by the flow coating method, and allowed to stand for 1 minute while the surface of the glass substrate was wet with this solution. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0098]
Using a scanning electron microscope (SEM, “S-4700”, manufactured by Hitachi, Ltd.), the surface shape of the glass plate coated with the silica film having the concavities and convexities thus obtained was subjected to an acceleration voltage of 5 kV, an emission current of 10 μA, and an inclination. Observation was performed under the conditions of an angle of 10 degrees and an observation magnification of 100,000 times (see FIG. 1). As is clear from the results of FIG. 1, it was confirmed that minute projections and columnar projections were formed on the surface of the silica film.
[0099]
As shown in FIG. 1, the columnar protrusions have a shape in which the fine particles locally grow in the film thickness direction of the film, specifically, more than twice or even three times the average height of the fine protrusions due to the fine particles. Having. Some columnar projections have a height H from the substrate of three times or more the average diameter Dc. H, Dc and the diameter Dp of the microprojections were within the above preferred ranges. The average values of Dp and Dc were both in the range of 20 nm to 100 nm.
[0100]
Further, the surface roughness of the glass plate coated with the silica film having irregularities can be calculated by using an atomic force microscope (AFM, “SPI3700”, manufactured by Seiko Instruments Inc.) in the cyclic contact mode in the arithmetic mean roughness Ra. It was measured. The greater the value of Ra, the greater the roughness of the film surface.
[0101]
Further, the hydrophilic performance of the glass plate coated with the silica film having irregularities was evaluated by the contact angle of water. Using a contact angle meter ("CA-DT", manufactured by Kyowa Interface Science Co., Ltd.), a water drop having a mass of 1 mg was dropped on the surface of the glass plate, and the static contact angle was measured. The smaller the value of the contact angle, the better the hydrophilicity.
[0102]
Further, the transparency of the glass plate coated with the silica film having irregularities was evaluated by the haze ratio. The haze ratio was measured using a direct-read haze computer (“HGM-2DM”, manufactured by Suga Test Instruments Co., Ltd.). The smaller the haze ratio, the higher the transparency of the film.
[0103]
As described above, the method for forming a film containing silicon oxide as a main component according to the present invention requires only natural drying, and does not particularly require a firing step.
[0104]
(Example 2)
A solution for coating a silica film that forms irregularities adjusted in the same manner as in Example 1 was applied to the surface of the washed glass substrate by flow coating at a relative humidity of 30% and room temperature, and the solution was applied for 1 minute with this solution. The glass substrate surface was allowed to stand with the surface wet. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0105]
(Example 3)
A coating solution for forming a silica film for forming irregularities adjusted in the same manner as in Example 1 was applied to the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and this solution was used for 10 seconds. The glass substrate surface was allowed to stand with the surface wet. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0106]
(Example 4)
A coating solution for forming a silica film for forming irregularities adjusted in the same manner as in Example 1 was applied to the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and this solution was applied for 0.5 second. The glass substrate surface was allowed to stand while being wet with the solution, and the same solution was again applied thereon by the flow coating method, and the glass substrate surface was allowed to stand with the solution wet for 0.5 seconds. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0107]
(Example 5)
Tetrachlorosilane (SiCl ₄ : Shin-Etsu Silicone Co., Ltd.) was added to 99.8 g of decamethylcyclopentasiloxane (KF-995: Shin-Etsu Silicone Co., Ltd.) with stirring to obtain a silica film coating solution for forming irregularities.
[0108]
The coating solution for the silica film for forming the irregularities is applied on the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and the glass substrate surface is allowed to stand for 1 minute with the solution wet. Was placed. Further, the same solution was again applied thereon by the flow coating method, and allowed to stand for 1 minute while the surface of the glass substrate was wet with this solution. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0109]
(Example 6)
Tetrachlorosilane (SiCl ₄ : Shin-Etsu Silicone) 1.0 g was added to 99.0 g of decamethylcyclopentasiloxane (KF-995: Shin-Etsu Silicone) with stirring to obtain a silica film coating solution for forming irregularities.
[0110]
The coating solution for the silica film for forming the irregularities is applied on the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and the glass substrate surface is allowed to stand for 1 minute with the solution wet. Was placed. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0111]
(Example 7)
A silica film-coated glass plate having irregularities was obtained in the same manner as in Example 1 except that decamethylcyclopentasiloxane of Example 1 was changed to octamethyltrisiloxane (KF-96L-1CS: manufactured by Shin-Etsu Silicone). .
[0112]
(Example 8)
A coating solution for forming a silica film for forming irregularities adjusted in the same manner as in Example 1 was applied to the surface of the washed glass substrate by a spray coating method at a relative humidity of 30% and room temperature, and this solution was used for 1 minute. The glass substrate surface was allowed to stand with the surface wet. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0113]
(Example 9)
Tetrachlorosilane (SiCl ₄ : Shin-Etsu Silicone) 2.0 g was added to 98.0 g of decamethylcyclopentasiloxane (KF-995: Shin-Etsu Silicone) with stirring to obtain a silica film coating solution for forming irregularities.
[0114]
The silica film coating solution for forming the irregularities is applied on the surface of the cleaned glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and the surface of the glass substrate is kept wet with the solution for 5 minutes. The solution was allowed to stand, the same solution was applied thereon again by the flow coat method, and the glass substrate surface was allowed to stand with the solution wet for 5 minutes. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities.
[0115]
The surface shape of the silica film-coated glass plate having the irregularities thus obtained was observed with a scanning electron microscope under the same conditions as in Example 1 (see FIG. 2). As is clear from the results of FIG. 2, it can be seen that the columnar protrusions in Example 9 are formed by overlapping particles. The columnar projections include those in which fine particles locally overlap in three or more steps, and fine particles protrude from surrounding fine particles as protrusions in two or more steps.
[0116]
Also here, some columnar projections have a height H from the substrate that is three times or more the average diameter Dc. H, Dc and the diameter Dp of the microprojections were within the above preferred ranges. The average values of Dp and Dc were both in the range of 20 nm to 100 nm.
[0117]
(Example 10)
The same procedure as in Example 1 was performed, except that the environment for applying the silica film coating solution for forming irregularities adjusted in the same manner as in Example 1 on the surface of the washed glass substrate was changed to a relative humidity of 20%. Thus, a glass plate coated with a silica film having irregularities was obtained.
[0118]
(Example 11)
The same procedure as in Example 1 was performed, except that the environment for applying the silica film coating solution for forming irregularities adjusted in the same manner as in Example 1 on the surface of the cleaned glass substrate was changed to 50% relative humidity. Thus, a glass plate coated with a silica film having irregularities was obtained.
[0119]
[Table 1]

[0120]
When the surface shape of the silica film-coated glass plate having irregularities obtained in Examples 1 to 11 was observed using a scanning electron microscope, microscopic projections and columnar projections were formed in all the coatings. And the surface roughness (Ra) was 13 nm or more in each case. As a result, it was confirmed that the surface roughness of the film was large.
[0121]
Further, the wettability of water was observed on the silica film-coated glass plate having irregularities obtained in Examples 1 to 11. As a result, it was confirmed that the water droplets spread well on all the films. Further, the hydrophilicity of the silica film having irregularities was evaluated by the contact angle of water. The contact angle was such that accurate measurement was not possible, and was about 5 degrees or less.
[0122]
Further, when the transparency of the silica film-coated glass plate having irregularities obtained in Examples 1 to 11 was measured by a direct-read haze computer, the haze ratio of all the films was 1.0% or less, and the transparency was high. It was confirmed that. Furthermore, it was confirmed that the film was very clean without defects in appearance such as unevenness of the film surface and liquid pool at the glass edge portion. Further, both the transmission color tone and the reflection color tone were neutral, and there was no problem in appearance.
[0123]
In addition, the film-coated glass plate containing silicon oxide as a main component according to the present invention has a film surface reflectance of about 1.6% as compared with a glass substrate not formed with a film containing silicon oxide as a main component. The rate was decreasing. This is considered to be due to the effect of the film mainly composed of silicon oxide, which has a lower refractive index than that of the soda-lime glass substrate having the refractive index of 1.52, and the effect of the film surface unevenness.
[0124]
(Application example: water-repellent treatment)
As an application example of the present invention, a water-repellent treatment was further applied to a glass plate coated with a silica film having irregularities according to the present invention.
[0125]
The water-repellent liquid that can be applied in this application example is not particularly limited as long as it contains a water-repellent material that binds to the substrate surface. Generally, a form in which a water-repellent material is used as a solution in a solvent is preferable. Further, a compound having a hydrolyzable silyl group that is compatible with the chlorosilyl group-containing compound previously formed on the substrate surface is preferable, and among them, a silane compound containing a fluoroalkyl group having high water repellency is more preferable.
[0126]
The fluoroalkyl group-containing silane compound is a silane compound containing a fluoroalkyl group and containing an alkoxy group, an acyloxy group, or a chlorine group. ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCl ₃ , CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ SiCl ₃ And the like.
[0127]
Among them, these can be used alone or in combination of two or more. ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCl ₃ Is most preferred.
[0128]
The solvent for dissolving the water-repellent material is not particularly limited as long as the water-repellent material dissolves. However, the chlorosilyl group-containing compound to be formed on the surface of the base material is first dissolved in a solvent containing silicone and applied. Therefore, the water repellent to be subsequently applied is also preferably a non-aqueous solvent of the same system.
[0129]
Examples of the non-aqueous solvent include a paraffin-based hydrocarbon, a fluorocarbon-based solvent, and a solvent containing a silicone oil as a main component. Solvents based on silicone oil are preferred.
[0130]
The method of applying the water-repellent liquid requires a method that does not break the surface shape of the silica film having the unevenness formed earlier, and specifically, a method of adsorbing the same as the previously formed chlorosilyl group-containing compound. preferable.
[0131]
In order to adsorb the water-repellent liquid, it is necessary that the water-repellent liquid wets the substrate surface for at least 0.1 second after the application of the water-repellent liquid.
[0132]
The water-repellent liquid is different from the chlorosilyl group-containing compound in which the silica film having the unevenness is formed first, so that only one layer of the water-repellent material needs to be bonded. The time may be shorter than the time required for natural adsorption lamination on the surface.
[0133]
However, if the time is less than 0.1 second, the water-repellent material is not sufficiently adsorbed, so that sufficient water-repellency cannot be exhibited.
[0134]
Examples of a method that enables such adsorption include a flow coating method, a dip coating method, a curtain coating method, a spin coating method, a spray coating method, a bar coating method, and a dip adsorption method. For efficient application, a flow coating method and a spray coating method are preferable.
[0135]
(Application Examples 1 to 11)
First, heptadecafluorodecyltrichlorosilane (CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCl ₃ 2) was added to 98 g of decamethylcyclopentasiloxane with stirring to obtain a water-repellent agent.
[0136]
This water-repellent agent is applied to the surface of the glass plate coated with the unevenness of the silica film of Examples 1 to 11 at a relative humidity of 30% and at room temperature by a flow coating method, and the water-repellent agent is treated for 1 minute. The glass substrate surface was allowed to stand with the surface wet, and then the surface water-repellent agent was completely washed away with ethanol and dried naturally to obtain water-repellent glass plates of Application Examples 1 to 11, respectively.
[0137]
First, the water repellency of the obtained water-repellent glass plate was evaluated based on the contact angle of water. Using a contact angle meter ("CA-DT", manufactured by Kyowa Interface Science Co., Ltd.), a water drop having a mass of 2 mg was dropped on the surface of the glass plate, and the static contact angle was measured. The larger the value of the contact angle, the better the static water repellency.
[0138]
Next, with respect to the obtained water-repellent treated glass plate, the transparency of the film was evaluated by a haze ratio. The haze ratio was measured using a direct-read haze computer (“HGM-2DM”, manufactured by Suga Test Instruments Co., Ltd.). The smaller the haze ratio, the higher the transparency of the film.
[0139]
Further, with respect to the obtained water-repellent treated glass plate, the abrasion resistance of the film was evaluated. The wear resistance test was performed by attaching a dry cloth to a reciprocating wear tester (manufactured by Shinto Kagaku Co., Ltd.) and applying a load of 125 g / cm. ² The water-repellent glass was slid 100 times under the conditions described above, and then the water contact angle of the water-repellent glass was measured under the same conditions as those before the test.
[0140]
[Table 2]

[0141]
The water-repellent treated glass plates obtained in Application Examples 1 to 11 exhibited an initial contact angle of 150 ° or more, and were confirmed to have super-water-repellency.
[0142]
The contact angles after the abrasion resistance test were 100 degrees or more, respectively, and although they did not exhibit super water repellency, they exhibited sufficiently normal water repellency and were confirmed to have excellent scratch resistance.
[0143]
Furthermore, the haze ratio was almost the same as that of the silica-coated glass plate having irregularities obtained in Examples 1 to 11, and it was confirmed that the haze ratios of all the films were 1.0% or less and the transparency was high. Was.
[0144]
(Comparative Example 1)
A coating solution for forming a silica film for forming irregularities adjusted in the same manner as in Example 1 was applied to the surface of the washed glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and this solution was applied for 0.5 second. The glass substrate surface was left standing with the solution wet. Thereafter, the silica film coating solution for forming the irregularities on the surface of the glass substrate was completely washed away with ethanol, and dried naturally to obtain a silica film-coated glass plate having irregularities. Water-repellent treatment was performed on the surface of the silica film-coated glass plate having the irregularities in the same manner as in Application Examples 1 to 11, to obtain a water-repellent treated glass plate.
[0145]
As a result of evaluating the obtained water-repellent treated glass plate in the same manner as in Application Examples 1 to 11, it was confirmed that the initial contact angle was 120 ° and the water-repellency was inferior to that of the application examples.
[0146]
(Comparative Example 2)
Tetrachlorosilane (SiCl ₄ : Shin-Etsu Silicone 4.0 g was added to decamethylcyclopentasiloxane (KF-995: Shin-Etsu Silicone) 96.0 g with stirring to obtain a silica film coating solution for forming irregularities.
[0147]
The silica film coating solution for forming the irregularities is applied on the surface of the cleaned glass substrate by a flow coating method at a relative humidity of 30% and room temperature, and the surface of the glass substrate is kept wet with the solution for 5 minutes. It was left still. Thereafter, the solution for coating the glass substrate surface was completely washed away with ethanol and air-dried to obtain a silica film-coated glass plate having irregularities. Water-repellent treatment was performed on the surface of the silica film-coated glass plate having the irregularities in the same manner as in Application Examples 1 to 11, to obtain a water-repellent treated glass plate.
[0148]
As a result of evaluating the obtained water-repellent treated glass plate in the same manner as in Application Examples 1 to 11, it was confirmed that the initial contact angle was 123 ° and the water-repellency was inferior to that of the application examples. In addition, a white powdery film was partially observed, the haze ratio was 3.8%, and the transparency was poor.
[0149]
(Comparative Example 3)
In Example 1, a silica film-coated glass plate having irregularities was obtained in the same manner as in Example 1 except that decamethylcyclopentasiloxane was changed to an isoparaffinic hydrocarbon (Isosol 300: manufactured by Nippon Petrochemical Co., Ltd.). Obtained. Water-repellent treatment was performed on the surface of the silica film-coated glass plate having the irregularities in the same manner as in Application Examples 1 to 11, to obtain a water-repellent treated glass plate.
[0150]
As a result of evaluating the obtained water-repellent treated glass plate in the same manner as in Application Examples 1 to 11, it was confirmed that the initial contact angle was 91 degrees and the water-repellency was inferior to that of the application examples.
[0151]
(Comparative Example 4)
The same procedure as in Example 1 was performed, except that the environment for applying the silica film coating solution for forming irregularities adjusted in the same manner as in Example 1 on the surface of the washed glass substrate was changed to a relative humidity of 10%. Thus, a glass plate coated with a silica film having irregularities was obtained. Water-repellent treatment was performed on the surface of the silica film-coated glass plate having the irregularities in the same manner as in Application Examples 1 to 11, to obtain a water-repellent treated glass plate.
[0152]
As a result of evaluating the obtained water-repellent treated glass plate in the same manner as in Application Examples 1 to 11, it was confirmed that the initial contact angle was 114 degrees, and the water-repellency was inferior to that of Application Example.
[0153]
(Application example: antifouling treatment)
(Application Example 12)
Instead of heptadecafluorodecyltrichlorosilane used in the application example of the water-repellent treatment, [methoxy (polyethyleneoxy) propyl] trimethoxysilane (manufactured by Chisso Corporation, content: 90%, molecular weight: 460 to 590, number of ethylene oxide units) A hydrophilic film with an antifouling function was obtained in the same manner as in Application Example 1 except that 6 to 9) was used.
[0154]
The wettability of water was observed on the obtained hydrophilic film having an antifouling function. As a result, it was confirmed that the water droplets were well wet and spread. The hydrophilicity was evaluated by the contact angle of water. The contact angle was such that accurate measurement was not possible, and was about 5 degrees or less. This was presumed to be due to the fact that the contact angle of the antifouling film itself was low, and the hydrophilicity was excellent due to the effect of the unevenness of the silica film having the unevenness formed earlier.
[0155]
Next, the antifouling performance of the hydrophilic film having the antifouling function was evaluated. A few drops of commercially available olive oil were dropped on the hydrophilic film with an antifouling function, allowed to stand at room temperature for 30 minutes, and then rinsed with ethanol. As a result, the olive oil was completely removed, and it was confirmed that the olive oil had an antifouling function.
[0156]
(Comparative Example 5)
The antifouling performance of the silica-coated glass sheet having irregularities of Example 1 was evaluated in the same manner as in Application Example 12. As a result, it was confirmed that olive oil partially remained, and the antifouling performance was inferior to that of Application Example 12.
[0157]
【The invention's effect】
As described above, the film containing silicon oxide as a main component according to the present invention is characterized in that fine particle projections are formed on the surface thereof, and furthermore, there are minute irregularities in which a part thereof is grown in a columnar shape. And For this reason, it is a film serving as a foundation for excellent hydrophilicity and water repellency.
[0158]
In the film containing silicon oxide as a main component, the diameter of the fine projections and the columnar projections forming the fine irregularities is 200 nm or less, and the average is about 50 nm. For this reason, while having sufficient unevenness which becomes the foundation of hydrophilicity and water repellency, there is an effect that the transparency of the film is high.
[0159]
Further, in the film containing silicon oxide as a main component, fine particulate protrusions are formed on the surface of the film, and a part of the protrusions is grown in a columnar shape. For this reason, the water-repellent-treated coating mainly composed of silicon oxide according to the present invention has sufficient ordinary water repellency even if the surface is abraded and no longer in a super water-repellent state. Therefore, it has an effect of being excellent in abrasion resistance.
[0160]
Further, in the film containing silicon oxide as a main component, minute particle-like projections are naturally formed, and a part thereof grows in a columnar shape.
[0161]
In addition, the method according to the present invention only requires applying a solution in which a chlorosilyl group-containing compound is dissolved in a solvent containing silicone oil as a main component to the surface of the base material. Thus, a film-coated article containing silicon oxide as a main component can be produced.
[0162]
Further, the coating of the present invention has an effect of exhibiting low reflectivity due to the effects of the refractive index and the surface unevenness.
[Brief description of the drawings]
FIG. 1 is an SEM observation photograph of a film containing silicon oxide as a main component obtained in Example 1.
FIG. 2 is an SEM observation photograph of a film containing silicon oxide as a main component obtained in Example 9.
FIG. 3 is a schematic view illustrating a mechanism of forming minute unevenness.
[Explanation of symbols]
1: (glass) substrate
2: applied solution
3: Nuclear
4: Oligomer
5: Chlorosilyl group-containing compound
6: oligomer (before precipitation)
7: Columnar projection
8: Particulate protrusion

Claims (23)

An article coated with a coating mainly composed of silicon oxide having fine irregularities on its surface,
The film-coated article, wherein the minute irregularities are constituted by minute projections and columnar projections. The columnar protrusions are formed by locally growing the fine protrusions in the thickness direction of the coating, and / or by locally laminating a plurality of fine particles constituting the fine protrusions. The coated article of claim 1. The film-coated article according to claim 1, wherein a relational expression of 2Dc ≦ H is satisfied, where Dc is the diameter of the columnar protrusion and H is the height. The coated article according to claim 3, wherein the Dc is 10 to 200 nm, and at least H is 50 nm. The film-coated article according to claim 1, wherein the microprojections have a diameter Dp of Dp = 5 to 200 nm. The coated article according to any one of claims 1 to 5, wherein the surface roughness of the coating is at least 10 nm in arithmetic average roughness (Ra), and the haze ratio of the coating is 1% or less. The film-coated article according to any one of claims 1 to 6, wherein a contact angle of water measured by dropping 1 mg of a water droplet on the surface of the film is 5 degrees or less. The film-coated article according to any one of claims 1 to 7, wherein the substrate is any one of a glass plate, a resin plate, and a resin film. A method for producing a film-coated article in which a substrate and a film containing silicon oxide as a main component are formed on the substrate surface,
A step of applying a solution containing a silicon-containing raw material on the surface of the base material,
Micro-projections containing silicon supplied from the silicon-containing raw material are formed on the surface, and the micro-projections locally grow in the thickness direction of the coating, and / or fine particles constituting the micro-projections are formed. A method for producing a film-coated article, comprising a step of forming columnar projections by locally laminating a plurality of articles. The method for producing a film-coated article according to claim 9, wherein the step of forming the columnar projections maintains the substrate surface wet with the solution for a time sufficient for the columnar projections to grow. The method according to claim 10, wherein the time is at least one second. The method for producing a film-coated article according to claim 9, wherein the locally grown columnar projections are formed by directly depositing a silicon-containing raw material dissolved in the solution on the surface of the substrate. The coating according to claim 9, wherein the stacked columnar projections are formed by depositing silicon-containing raw materials dissolved in the solution as fine particles in the solution and depositing the fine particles on the surface of the base material. A method for producing a coated article. The method for producing a film-coated article according to claim 9, wherein the solution is obtained by dissolving a chlorosilyl group-containing compound in a solvent containing silicone oil as a main component. The method for producing a film-coated article according to claim 14, wherein the concentration of the chlorosilyl group-containing compound is 0.01 to 10% by mass. The method according to claim 14 or 15, wherein the chlorosilyl group-containing compound is tetrachlorosilane. The method for producing a film-coated article according to any one of claims 14 to 16, wherein the solvent containing silicone oil as a main component is dimethyl silicone oil. The method for producing a film-coated article according to claim 9, wherein the coating step and the step of forming the columnar projections are performed under environmental conditions of a temperature of 10 to 40C and a relative humidity (RH) of 15 to 60%. The method according to any one of claims 9 to 18, wherein the substrate is any one of a glass plate, a resin plate, and a resin film. The method according to any one of claims 9 to 19, wherein the substrate is a transparent plate for a vehicle mounted on a vehicle. A coating solution for forming a film, wherein a chlorosilyl group-containing compound is dissolved in a solvent containing silicone oil as a main component. The coating solution for forming a film according to claim 21, wherein the water content in the solvent containing the silicone oil as a main component is 0.03% by mass or less. 22. The coating solution for forming a film according to claim 21, wherein the concentration of the chlorosilyl group-containing compound is 0.01 to 10% by mass.

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