JP2000289134A - Article having hydrophilic surface and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-fog and anti-fouling article excellent in hydrophilicity keeping capacity after the stop of the irradiation with ultraviolet rays and keeping good anti-fog and anti-fouling capacity over a long period of time. SOLUTION: In an article having a hydrophilic surface having a substrate, the photocatalyst layer applied thereon and the hydrophilic metal oxide layer applied on the photocatalyst layer, the hydrophilic metal oxide layer contains fine particles of hydrophilic metal oxide and a binder of hydrophilic metal oxide and the article has irregularities on its surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article having a substrate surface made of glass, ceramics, plastic, metal or the like made hydrophilic, and a method for producing the same.

[0002]

2. Description of the Related Art There has been a strong need for anti-fogging and anti-fouling glass plates for a long time mainly in the field of automobiles and construction. Particularly in automobiles, the provision of anti-fog properties on window glass is becoming an important issue from the viewpoint of safe driving.

[0003] Various anti-fog coatings on glass articles have been studied in the past. For example, a coating of an organic and / or inorganic thin film containing a surfactant (JP-A-7-117202, method 1), a coating of a hydrophilic polymer (patent 1344292, method 2), an organic-inorganic film containing a hydrophilic organic functional group Coating of a composite film (JP-A-6-220428, Method 3).

[0004] Although the above method 1 is excellent in the initial performance, it has a drawback that the life is short because the surfactant is gradually consumed. Method 2 is an effective means depending on the application, but cannot be applied to glass requiring relatively large mechanical strength, such as automobiles and buildings. Method 3 is devised in order to achieve both anti-fog performance and mechanical strength, but all have limitations in performance. Further, there is also a problem that the antifogging performance is remarkably deteriorated once the stain is attached.

[0005] Therefore, recently, an antifogging and antifouling article in which titanium oxide, which is an oxide semiconductor acting as a photocatalyst, is coated on the surface of a substrate has been proposed (Japanese Patent No. 2756474, Method 4). This is based on the fact that titanium oxide on the surface of glass absorbs ultraviolet light, and the energy that is used to efficiently oxidize and decompose organic substances adsorbed on the glass surface, resulting in a clean surface with remarkable hydrophilicity. It is. In addition, the material is entirely composed of an inorganic material and has excellent mechanical strength. Even if dirt adheres, the surface is cleaned again and the hydrophilic surface is restored once it is irradiated with ultraviolet light. If the surface maintains hydrophilicity, lipophilic black stains, which are urban-type stains, are unlikely to adhere, and the attached stains are easily removed by rainfall (for example, Toshiki Komatsuzawa, Toshikazu Nakaya, "New Stain Prevention Paints" Coating Technology, January 1995, 94-99 (19
95); Tanaka, Shoichi, "Stain Deterioration and Stain-Resistant Paint Technology (Industrial Paint)", Coating Technology, October 1996 Special Issue, 95-102 (1995). ), Which has a so-called self-cleaning property and can be used as an antifouling material.

Examples of the article having a hydrophilic surface using a photocatalyst such as titanium oxide include a mixture of a photocatalyst and silica (eg, Japanese Patent No. 2756474), and a metal compound layer such as silica on a photocatalyst layer. A formed one (for example, Japanese Patent No. 2865065, Japanese Patent Application Laid-Open No. 10-57817) and the like have been proposed.

[0007] Metal oxides other than silica (for example, oxides of molybdenum and tungsten) contained in the photocatalyst layer or those formed as a surface layer on the photocatalyst layer (Japanese Patent Application Laid-Open Nos. 10-147770 and 10-147770) 10-152
346) has also been proposed as a member capable of maintaining antifogging properties for a long period of time (method 5).

In Japanese Patent Application Laid-Open No. 10-36144, a film of a hydrophilic metal oxide such as silica is formed in a porous form on a photocatalytic film on the surface of a transparent substrate member. An anti-fog element with an opening reaching the photocatalytic layer is described (method 6). When the porous opening reaches the photocatalyst layer in this way, organic substances and the like that have entered the porous opening come into direct contact with the photocatalytic film and are decomposed and removed by the photocatalytic reaction, so that the antifogging property is maintained for a long time Is done.

[0009]

However, method 4
In these articles based on the method 6 and the method 6, the hydrophilicity maintenance performance (the hydrophilicity maintenance performance after stopping the ultraviolet irradiation) of the surface hydrophilicized by the ultraviolet irradiation is not sufficient. There was a problem that said it was not very good. In addition, due to this, the antifouling property and the self-cleaning property are not sufficient, and there is a problem that the antifouling performance at a location where light does not hit much is not sufficient.

The method 5 aims at improving the photocatalytic activity and maintaining the antifogging property for a long period of time by combining a photocatalyst with a metal or an oxide thereof. When added, problems such as a decrease in film transparency and mechanical strength occur.

In view of the above prior art, the present invention has excellent hydrophilicity maintaining performance after stopping ultraviolet irradiation and maintains good antifogging and antifouling performance for a long period of time, for example, window glasses of automobiles and buildings, It is an object of the present invention to provide an antifogging and antifouling article having excellent antifogging and antifouling performance that can be used for mirrors, optical parts, glasses, and the like.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have set fine particles of a hydrophilic metal oxide such as silicon oxide on a photocatalytic layer such as titanium oxide. When fixed by a binder of a conductive metal oxide to form a concavo-convex layer, it has been found that the hydrophilicity caused by ultraviolet irradiation is maintained for a long time even in a dark place, and that the concavo-convex layer is in the form of an island, a film having a hole. And the formation of a network, it was found that the hydrophilicity was restored even by a weak ultraviolet ray, and the present invention was completed. By not adding hydrophilic metal oxide fine particles directly to the photocatalyst layer and fixing it on the photocatalyst layer via a binder of hydrophilic metal oxide, the transparency and mechanical strength of the film are also secured at the same time. There is.

That is, the present invention relates to an article having a hydrophilic surface, comprising a substrate, a photocatalyst layer coated thereon, and a layer of a hydrophilic metal oxide coated on the photocatalyst layer. The hydrophilic metal oxide layer contains hydrophilic metal oxide fine particles and a hydrophilic metal oxide binder for fixing the fine particles to the photocatalytic layer, and the article has irregularities on its surface. An article having a hydrophilic surface.

In the present invention, the photocatalyst layer is made of TiO.
_{2, ZnO, SnO 2, SrTiO} 3, WO 3, Bi 2 O 3,
A layer of a metal oxide semiconductor such as Fe ₂ O ₃ , In ₂ O ₃ , and MoO ₂ can be given. Among them, titanium oxide (Ti) having high catalytic activity and excellent physicochemical stability
O ₂ ) is preferably used.

The formation of the photocatalyst layer is carried out by using a usual thin film manufacturing method, and is not particularly limited. However, even if a photocatalytic film such as a titanium oxide film is directly coated on the glass substrate surface, high photocatalytic activity may not be obtained. This is because alkali metal ions such as Na ions diffused out of the glass substrate containing the alkali metal during the heat treatment combine with the titanium oxide and reduce the crystallinity of the titanium oxide in the film. It is. When a glass material containing an alkali metal is used as the base material, a silicon oxide film or another alkali blocking film is provided on the glass base material to prevent a decrease in the crystallinity of the titanium oxide film. Coating a photocatalytic film containing titanium oxide.

[Alkali barrier film] As the alkali barrier film, those having a single component or a multicomponent composition selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide and cerium oxide are preferably used. Is done. Among these, a single component of silicon oxide (silica) or a multicomponent component whose main component is silicon oxide is preferable, and a two-component metal oxide of silicon oxide and zirconium oxide is more preferable. A metal oxide whose main component is silicon oxide has a low refractive index and can be formed without significantly deteriorating the optical characteristics of the glass plate. A two-component metal oxide of silicon oxide and zirconium oxide is preferably an alkali metal. The barrier performance is very high, so that it is more preferable. The content of zirconium oxide is particularly preferably from 1% by weight to 30% by weight. When the content is less than 1% by weight, the effect of improving alkali barrier performance is not so different from that of silicon oxide alone, and when the content is more than 30% by weight, the effect of improving alkali barrier performance is no longer improved, and the reflectance is increased by increasing the refractive index. This is not preferable because the tendency to occur is increased and it becomes difficult to control the optical characteristics of the glass plate.

The thickness of the alkali barrier film is preferably 5 nm or more and 300 nm or less. If the thickness is less than 5 nm, the alkali blocking effect is not sufficient, and 300 n
When the thickness is larger than m, interference colors due to the film become remarkable, and it becomes difficult to control the optical characteristics of the glass plate, which is not preferable.

The alkali barrier film can be formed by a known method. For example, the sol-gel method (for example, Yuji Yamamoto, Kanichi Kamiya, Saio Sakuhana, Journal of the Ceramic Society of Japan, 90, 328-333 (1
982)), liquid phase deposition method (for example, Japanese Patent Publication No. 1-5921)
0, Japanese Patent Publication No. 4-13301), vacuum film forming method (vacuum deposition,
Spattering), baking method, spray coating (for example, JP-A-53-124523 and JP-A-56-96849), CV
Method D (for example, JP-A-55-90441, JP-A-1-20
1046, JP-A-5-208849).

[Photocatalyst Layer] The photocatalyst layer in the present invention is produced by using a usual thin film production method, for example, a sol-gel method, a liquid phase deposition method (for example, Patent 2716244), a vacuum film formation method (vacuum deposition, sputtering). , Baking method, spray coating, CVD method and the like.

As the photocatalyst layer, titanium oxide having high catalytic activity and excellent physicochemical stability is preferably used.
Preferably, it is contained in an amount of from 100% to 100%. If the content of titanium oxide is less than 30%, the photocatalytic activity is not sufficient, and the rate of hydrophilization by light irradiation is reduced, and as a result, the hydrophilicity maintaining performance is not good, which is not preferable. Examples of substances that can be contained in the photocatalyst layer in addition to the titanium oxide crystal include silicon oxide, aluminum oxide, alkali metal, zirconia, antimony oxide, amorphous titanium oxide, hydrous titanium oxide, aluminum, manganese, Ge
O ₂ , ThO ₂ , ZnO, SnO ₂ , SrTiO ₃ , W
O ₃ , Bi ₂ O ₃ , Fe ₂ O ₃ , In ₂ O ₃ , MoO ₂ ; magnesium (Mg), scandium (Sc), vanadium (V), chromium (Cr), manganese (Mn), yttrium (Y) , Niobium (Nb), molybdenum (Mo), ruthenium (Ru), tungsten (W) and rhenium (Re). The content of these additives is preferably from 1 to 70% by weight.

The thickness of the photocatalyst film is preferably from 2 to 500 nm. When the thickness is less than 2 nm, light cannot be sufficiently absorbed, and the antifogging and antifouling performance is lowered. When the thickness is more than 500 nm, the photocarriers generated in the film cannot diffuse to the outer surface of the film, so that the photocatalytic activity is reduced, and as a result, the antifogging and antifouling performance is reduced, and interference colors are remarkably recognized. Absent. Also, if the thickness is 20
When the thickness is at least nm, the antifogging and antifouling durability when light is not applied will be further increased, and when the thickness is at most 200 nm, the abrasion resistance will be further increased. Therefore, a more preferable thickness of the photocatalytic film is 20 to 200 nm.

[Overcoat Layer] In the present invention, the hydrophilic metal oxide layer (hereinafter referred to as the overcoat layer) coated on the photocatalyst layer comprises fine particles of the hydrophilic metal oxide and the fine particles of the photocatalyst. An uneven film is formed on the photocatalyst layer by a binder of a hydrophilic metal oxide for fixing to the layer.

The overcoat layer may be formed in the form of a concavo-convex layer completely covering the photocatalyst layer.
It is preferable that the photocatalyst layer is formed in the form of an island-like, perforated film-like or network-like uneven layer, and has an opening reaching the photocatalyst layer.

The fine particles of the hydrophilic metal oxide constituting the overcoat layer include a single component selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, molybdenum oxide, vanadium oxide and cerium oxide. Metal oxide fine particles, a mixture thereof, and composite metal oxide fine particles comprising two or more of these components are used. The particle size of the hydrophilic metal oxide fine particles is 4n
It is preferably from m to 300 nm. By using the fine particles having a particle diameter in this range, the surface unevenness after the formation of the overcoat layer becomes an appropriate value, and the performance of maintaining hydrophilicity is further improved. When fine particles smaller than 4 nm are used, it is difficult to form necessary irregularities on the surface of the overcoat layer, and the arithmetic average roughness (Ra) of the surface irregularities is less than 0.5 nm. In use, the transparency tends to be impaired by the formation of the overcoat layer, which is not preferable.

As the hydrophilic metal oxide fine particles, chain fine particles are preferable. By using chain-shaped fine particles, the overcoat layer has a three-dimensionally intricate uneven surface, so that it is possible to form a surface unevenness with high antifogging performance and antifogging durability, Since an opening reaching the photocatalyst layer is easily formed in the overcoat layer, a surface shape with higher antifogging performance and antifogging durability can be formed. Examples of chain colloids include "Snowtex-O", a silica sol manufactured by Nissan Chemical Industries, Ltd.
UP "and" Snowtex-UP ", which have a diameter of 10-20 nm and a length of 40-300 nm.

As a binder of the hydrophilic metal oxide constituting the overcoat layer, at least one kind selected from silicon oxide, aluminum oxide, cerium oxide, zirconium oxide, molybdenum oxide, vanadium oxide and amorphous titanium oxide is used. It is preferably a metal oxide,
More preferably, it contains at least 50% by weight of silicon oxide. When silicon oxide is contained in an amount of 50% by weight or more, the effect of improving hydrophilicity is remarkable.

In the overcoat layer, aluminum (A
l), magnesium (Mg), iron (Fe), scandium (Sc), vanadium (V), chromium (Cr), manganese (Mn), yttrium (Y), niobium (Nb),
Compounds of molybdenum (Mo), ruthenium (Ru), tungsten (W) and rhenium (Re), for example, oxide fine particles of these metals (substances different from the hydrophilic metal oxide fine particles used) are added. By doing so, the aggregation of the hydrophilic metal oxide is promoted, and as a result, a good uneven shape can be formed, and an island-like, perforated film-like or network-like overcoat layer can be easily formed. Can be. The addition amount of these compounds is not particularly limited, but is preferably 0.01 to 50% by weight. 0.01
If the amount is less than 50% by weight, the effect of the addition is not sufficient,
If the amount is more than the percentage by weight, the mechanical strength of the overcoat layer decreases, which is not preferable. Among the above additives, aluminum (Al), magnesium (Mg), iron (Fe),
Vanadium (V), niobium (Nb), molybdenum (M
o) is particularly preferably used because, in addition to the effect of the above addition, the hydrophilicity of the overcoat layer itself is particularly increased.

The overcoat layer preferably has an average thickness of 0.01 to 50 nm. If the average thickness is smaller than 0.01 nm, the effect of the overcoat is low, that is, the hydrophilic property is not improved, which is not preferable.
When the average thickness is larger than 50 nm, the recovery performance of hydrophilicity or anti-fog property by light irradiation is reduced, and it is difficult to form an island, a film with holes or a mesh, and even if such a form is provided. Even if it can be done, the strength of the film is undesirably reduced. When the average thickness is 0.1 nm or more, the antifogging durability is further improved, and when it is 20 nm or less, the wear resistance is further increased. Therefore, the average thickness of 0.1 to 20 nm is more preferable.

With respect to the content of the hydrophilic metal oxide fine particles and the hydrophilic metal oxide binder constituting the overcoat layer, when the content of the hydrophilic metal oxide binder is too low (hydrophilic metal oxide fine particles) When the content is too large), the adhesion of the hydrophilic metal oxide fine particles becomes insufficient, and the overcoat layer becomes brittle, and the mechanical strength, particularly the abrasion resistance, decreases. On the other hand, when the amount of the binder of the hydrophilic metal oxide is too large (when the content of the hydrophilic metal oxide fine particles is too small), formation of the uneven overcoat form is not sufficient, and When trying to form an open film-like or network-like overcoat layer, the binder fills the gaps between the hydrophilic metal oxide fine particles so that no void remains, so that the overcoat layer It is difficult to form an opening in the hole. Accordingly, the overcoat layer preferably contains 5% by weight or more and 95% by weight or less of hydrophilic metal oxide fine particles. In other words, the content of the hydrophilic metal oxide binder is preferably 5 to 1900% by weight based on the weight of the hydrophilic metal oxide fine particles. More preferably, it is 5 to 400% by weight, and still more preferably 5 to 400% by weight.
0 to 200% by weight.

The surface irregularities of the overcoat layer preferably have an arithmetic average roughness (Ra) of 0.5 to 100 nm and an average interval (Sm) of the irregularities of 4 to 300 nm. If the Ra value is smaller than 0.5 nm or larger than 100 nm, the antifogging performance and the antifogging durability are low, which is not preferable. Also, even if the Sm value is smaller than 4 nm,
Even if it is larger, the anti-fog performance and anti-fog persistence are still low,
Not preferred. Especially when the Sm value is larger than 300 nm,
This is not preferable because transparency is impaired. The surface unevenness of the overcoat layer of the present invention more preferably has an arithmetic average roughness (Ra) of 5 to 30 nm and an average interval (Sm) of unevenness of 5 to 150 nm. Within this range, the antifogging performance, especially the antifogging durability, is further improved.

Here, the Ra value and the Sm value are based on JIS B
0601 (1994) and an atomic force microscope (for example, SPI3 manufactured by Seiko Instruments Inc.)
700) or an electron microscope (for example, H-600 manufactured by Hitachi, Ltd.).

In the island-like overcoat layer, fine particles of the hydrophilic metal oxide or aggregates thereof are formed on the surface of the photocatalyst layer.
Attached in the form of islands at a distance from each other, the hydrophilic metal oxide binder adheres the hydrophilic metal oxide fine particles or aggregates thereof to the photocatalytic layer, or forms the hydrophilic metal oxide. The particles are bonded together. On the surface of the photocatalyst layer, a surface portion other than the portion where the hydrophilic metal oxide fine particles or the aggregates thereof are attached is exposed and communicates with the outside air through the opening of the overcoat layer. The average diameter of the islands is preferably 5 to 500 nm.

In a perforated film-like or network-like overcoat layer, the hydrophilic metal oxide fine particles or their aggregates are attached to the surface of the photocatalyst layer while being connected to each other, and the hydrophilic metal oxide binder In this method, hydrophilic metal oxide fine particles or aggregates thereof are bonded to the photocatalyst layer, or hydrophilic metal oxide fine particles or aggregates thereof are bonded to each other. Of the surface of the photocatalyst layer, the surface portion other than the portion to which the fine particles of the hydrophilic metal oxide or the aggregate thereof are attached is exposed, and is exposed to the outside air through holes or mesh openings (through holes) of the overcoat layer. I have. The average diameter of the holes or mesh openings is preferably 5 to 500 nm.

As described above, when the overcoat layer is formed on the photocatalyst layer in the form of an island, a perforated film or a mesh-like uneven layer, and has an opening reaching the photocatalyst layer,
Since the surface of the photocatalyst layer is partially covered with the hydrophilic metal oxide and the other portions are not covered with the hydrophilic metal oxide, the photocatalytic activity of the photocatalyst layer is not significantly reduced. Therefore, along with the improvement in hydrophilicity due to the formation of the overcoat, the ability to decompose surface dirt by light irradiation and the ability to recover hydrophilicity and antifogging properties due to light irradiation are maintained without being significantly impaired.

Further, by forming an overcoat layer having an opening reaching the photocatalyst layer, the recovery performance of hydrophilicity and antifogging property by light irradiation may be improved as compared with before the overcoat is formed. Although the cause is unknown, it is often found when the overcoat layer contains silica and the photocatalyst layer contains titanium oxide.

The surface area of the photocatalyst layer is 10 to 9
Preferably, 0% of the surface portion is exposed and faces the opening of the hydrophilic metal oxide layer. 10% exposed surface area
With the above, the decrease in photocatalytic activity is small, and the ability to decompose surface dirt by light irradiation and the ability to recover hydrophilicity and antifogging properties by light irradiation are improved. Conversely, when the exposed surface area is 90% or less, the effect of improving the hydrophilicity by forming the overcoat layer is remarkable. A more preferable exposed surface area ratio is 30 to 70.
%. Within this range, the balance between the improvement in hydrophilicity due to the formation of the overcoat layer and the ability to recover hydrophilicity due to exposure of the photocatalytic layer is balanced, and is most preferable.

The overcoat layer having an opening reaching the photocatalyst layer is composed of hydrophilic metal oxide fine particles and a hydrophilic metal oxide binder, and a gap (space) is generated between adjacent fine particles and an aggregate thereof. The opening is formed. In order for the photocatalytic activity of the photocatalyst layer to effectively act to improve the decomposition performance of surface dirt, not only the exposed surface area ratio of the photocatalyst layer but also the openings or voids inside the overcoat layer are important. Void W in the volume of the layer (measured by the space between the surface of the photocatalyst layer and the surface connecting the most convex portion of the overcoat layer) V (from V to the fine particles of the hydrophilic metal oxide and the binder of the hydrophilic metal oxide) Is preferably 10 to 90%, more preferably 30 to 70% for the same reason as the exposed surface area ratio of the photocatalyst layer.

The coating of the overcoat layer is produced by using a known thin film production method, for example, a sol-gel method,
A liquid phase deposition method, a baking method / spray coating, a CVD method and the like can be exemplified, but a sol-gel method is preferably used because the surface morphology of the overcoat layer is easily adjusted.

As a method for forming the overcoat layer, a group consisting of a hydrolyzable / polycondensable organometallic compound, a chlorosilyl group-containing compound, and a hydrolyzate thereof, each of which can form a hydrophilic metal oxide. A method comprising forming a liquid obtained by adding hydrophilic metal oxide fine particles to a liquid containing at least one selected from the above, on a substrate on which the photocatalytic layer is formed (hereinafter referred to as a method (A)). ) Can be exemplified.

In the above forming method, the hydrolyzable / polycondensable organometallic compound capable of forming a hydrophilic metal oxide is an organometallic compound of silicon, aluminum, titanium, zirconium, molybdenum, vanadium or cerium. Is used. Further, as the hydrophilic oxide fine particles, silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, molybdenum oxide, vanadium oxide, single-component metal oxide fine particles selected from the group consisting of cerium oxide, and mixtures thereof, Further, composite metal oxide fine particles composed of two or more of these components are used. These are preferably used in the form of a solvent dispersion sol (colloid solution). However, a combination of an organometallic compound of titanium and titanium oxide fine particles is inappropriate because the resulting metal oxide does not exhibit hydrophilicity.

Examples of the solvent dispersion sol of the metal oxide include “Snowtex-OL” and “Snowtex-O” which are silica sols manufactured by Nissan Chemical Industries, Ltd.
"Snowtex-OUP", "Snowtex-U"
P ", the company's alumina sol" Alumina Sol 520 ",
The company's zirconia sol "NZS-30A", Ishihara Sangyo Co., Ltd. titania sol "CS-N", "STS-0"
1 "," STS-02 ", ceria sol" Needral U-15 ", Titania sol" M-6 "manufactured by Taki Kagaku Co., Ltd.
Commercially available water-dispersed sols such as "IPA-ST" and "XBA-ST" manufactured by Nissan Chemical Industries, and "ST-K0" manufactured by Ishihara Sangyo Co., Ltd.
Commercially available water-alcohol mixed solvent-dispersed titania sol containing a binder, such as "1" and "ST-K03".

The solvent for dispersing the metal oxide fine particles is not particularly limited as long as the metal oxide fine particles are substantially stably dispersed, but is preferably a simple substance or a mixture of water, methanol, ethanol, propanol and the like. Water is more preferred. These water and lower alcohol may be easily mixed with the solution containing the organometallic compound, and may be easily removed by drying during film formation or heat treatment after film formation. Of these, water is the most preferable in the production environment.

When the metal oxide fine particles are added to the solution containing the organometallic compound or the chlorosilyl group-containing compound, a dispersing aid may be added. The dispersing aid is not particularly limited, and is generally used as a dispersing aid, for example, sodium phosphate, sodium hexametaphosphate, potassium pyrophosphate, aluminum chloride, electrolytes such as iron chloride,
Various surfactants, various organic polymers, silane coupling agents, titanium coupling agents and the like are used. The addition amount is usually 0.01 to 5 with respect to the metal oxide fine particles.
% By weight.

The organic metal compound capable of forming a hydrophilic metal oxide and capable of forming a hydrophilic metal oxide, which is included in the coating solution for forming the overcoat layer together with the metal oxide fine particles, includes hydrolyzable and polycondensable compounds. Basically, any compound may be used as long as it performs dehydration condensation, but metal alkoxides and metal chelates are preferred.

As the metal alkoxide, specifically, methoxide such as silicon, aluminum, zirconium and titanium, ethoxide, propoxide, butoxide and the like are preferably used alone or as a mixture. As the metal chelate, an acetylacetonate complex such as silicon, aluminum, zirconium, and titanium is preferably used.

As the silicon alkoxide, a high molecular weight type alkyl silicate such as “Ethyl silicate 40” manufactured by Colcoat Co., Ltd. or “M” manufactured by Mitsubishi Chemical Corporation
S56 "can also be used. As a hydrolyzate of silicon alkoxide, commercially available alkoxysilane hydrolyzate such as “HAS-1” manufactured by Colcoat Co., Ltd.
"Ceramica G-91" manufactured by Nippon Laboratories, Inc.
"Ceramica G-92-6", "Atron NSI-500" manufactured by Nippon Soda Co., Ltd. and the like can be used.

The compound containing a chlorosilyl group, which can be formed into a coating liquid for forming an overcoat layer together with the fine particles of a hydrophilic metal oxide and can form a hydrophilic metal oxide, includes a chlorosilyl group (—SiCl _n X _3-n , wherein n is 1, 2 or 3, and X is hydrogen or an alkyl group, an alkoxy group, or an acyloxy group each having 1 to 10 carbon atoms) in the molecule. Compounds. Among them, compounds having at least two chlorines are preferable, and at least two hydrogens in silane Si _n H _{2n + 2} (where n is an integer of 1 to 5) are substituted with chlorine, and other hydrogens are required. Depending on the above, chlorosilanes substituted with the above alkyl group, alkoxy group, or acyloxy group, and polycondensates thereof are preferable.

For example, tetrachlorosilane (silicon tetrachloride, SiCl ₄ ), trichlorosilane (SiHCl ₃ ),
Trichloromethyl monomethyl silane (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) and the like. Hydrolysates of the above-mentioned chlorosilyl group-containing compounds can also be used, and from these, they can be used alone or in combination of two or more. The most preferred compound containing a chlorosilyl group is tetrachlorosilane. Since the chlorosilyl group has a very high reactivity, by performing self-condensation or a condensation reaction with the substrate surface,
A dense film can be formed.

The solvent of the solution containing the above-mentioned organometallic compound or chlorosilyl group-containing compound or a hydrolyzate thereof can be basically prepared by dissolving the above-mentioned organometallic compound or chlorosilyl group-containing compound or a hydrolyzate thereof. Anything. Specifically, alcohols such as methanol, ethanol, propanol, and butanol are most preferable, and the total of the above-mentioned organometallic compound, chlorosilyl group-containing compound, and hydrolyzate thereof is contained at a concentration of 1 to 30% by weight. it can.

Water is required for the hydrolysis of the organometallic compound. It may be acidic or neutral, but in order to promote hydrolysis, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, citric acid, sulfonic acid, or the like having a catalytic action is preferably used as acidified water. .

The amount of water required for the hydrolysis of the above-mentioned organometallic compound is from 0.1 to 0.1 in molar ratio to the organometallic compound.
100 is good. If the amount of water added is less than 0.1 in molar ratio, the promotion of hydrolysis of the organometallic compound is not sufficient, and if the amount is more than 100, the stability of the liquid tends to decrease, which is not preferable.

The amount of the acid added is not particularly limited, but is preferably 0.001 to 20 in terms of a molar ratio with respect to the organometallic compound. If the amount of the added acid is less than 0.001 in molar ratio, the promotion of the hydrolysis of the organometallic compound is not sufficient, which is not preferable, and if it is more than 20, the acidity of the solution becomes too strong,
It is not preferable in handling. From the viewpoint of hydrolysis alone,
The upper limit of the amount of the added acid is 2 in a molar ratio with respect to the organometallic compound.
It is. Even if the acid amount is further increased, the degree of progress of the hydrolysis does not change much. However, the addition of more acid significantly increases the strength of the film and lowers the temperature (from room temperature to 250
(° C.) in some cases, a film that can sufficiently withstand practical use may be obtained.

The preferred composition of the coating liquid in which such an increase in film strength is observed is such that the concentration of the metal oxide calculated from the organometallic compound or the hydrolyzate thereof is 0.
00001-0.6% by weight, acid 0.0001-2.0
Mol / L, water content is 0.001 to 20% by weight.

When the hydrophilic metal oxide layer is coated with an opening reaching the photocatalyst layer, the preferred composition of the coating solution is such that the concentration of the metal oxide calculated from the organometallic compound or its hydrolyzate is: 0.00001-
0.3% by weight, 0.0001 to 1.0 mol / L of acid, and 0.001 to 10% by weight of water. When a hydrophilic metal oxide layer having no opening reaching the photocatalyst layer is coated, a preferable composition of the coating solution is such that the concentration of the metal oxide calculated from the organometallic compound or the hydrolyzate thereof is 0. 01-0.6% by weight, acid is 0.1-2.
0 mol / L, water content is 0.01 to 20% by weight.

The acid used at this time is preferably nitric acid or hydrochloric acid, and it is preferable to use an acid having a concentration of at least 0.3 times the water content. That is, when an acid in the form of an aqueous solution is used, it is preferably a high-concentration acid having a concentration of 23.1% or more. When the acid is used in the form of an ethanol solution, if the ethanol solution contains, for example, 0.5% by weight of water, the concentration of the acid in the ethanol solution is 0.15% by weight or more. preferable.

When the chlorosilyl group-containing compound is used, it is not always necessary to add water or an acid. Even if no additional water or acid is added, hydrolysis proceeds due to moisture contained in the solvent or moisture in the atmosphere.
In addition, hydrochloric acid is released into the liquid with the hydrolysis, and the hydrolysis further proceeds. However, it does not matter if water or acid is additionally added.

The above-mentioned metal oxide fine particles and the above-mentioned organometallic compound, chlorosilyl group-containing compound or a hydrolyzate thereof are mixed with a solvent, and if necessary, water, an acid catalyst,
And a dispersing aid, to prepare a coating solution for forming an overcoat layer on the substrate. At this time, the organometallic compound and the chlorosilyl group-containing compound may be used alone or as a mixture. The preferred raw material mixing ratio of this coating liquid is as shown in Table 1 below. In addition, when coating | covering the layer of the hydrophilic metal oxide which does not have an opening which reaches a photocatalyst layer, it is preferable that the solvent amount in a table | surface is 500-3000 weight part.

[0058]

[Table 1] Organometallic compounds or chlorosilyl group-containing compounds or their compounds Hydrolyzate 100 parts by weight Metal oxide fine particles 10 to 200 parts by weight Water 0 to 150 parts by weight Acid catalyst 0 to 35 parts by weight Dispersing aid 0.001 to 10 parts by weight Solvent 500 to 300,000 parts by weight ──────────────────────────────

The above organometallic compound or chlorosilyl group-containing compound is dissolved in a solvent, a catalyst and water are added, and the mixture is hydrolyzed at a predetermined temperature between 10 ° C. and the boiling point of the solution for 5 minutes to 2 days. The metal oxide fine particles and a dispersing aid are added thereto as needed, and the mixture is further reacted at a predetermined temperature between 10 ° C. and the boiling point of the solution for 5 minutes to 2 days as needed. obtain.

When a chlorosilyl group-containing compound is used, it is not necessary to add a catalyst and water. The metal oxide fine particles may be added before the hydrolysis step. Further, in order to omit the step of hydrolyzing the organometallic compound, the above-mentioned commercially available hydrolyzate of the organometallic compound may be used. The obtained coating liquid may be subsequently diluted with an appropriate solvent according to the coating method.

The coating solution for forming the overcoat layer is coated on a photocatalytic layer made of titanium oxide or the like, and dried,
A heat treatment can be applied, if necessary, to form a layer of a hydrophilic metal oxide on the photocatalyst layer, which is coated with an opening reaching the photocatalyst layer, or is completely coated.

The coating method may be a known one, and is not particularly limited. Examples thereof include a method using an apparatus such as a spin coater, a roll coater, a spray coater, and a curtain coater, a dipping and pulling method (dip coating method), Methods such as a flow coating method (flow coating method) and various printing methods such as screen printing, gravure printing, and curved surface printing are used.

The coated substrate is dried at a temperature between room temperature and 150 ° C. for 1 minute to 2 hours, and then dried at 150 ° C. if necessary.
It is preferable to perform a heat treatment at a temperature between the temperature and the heat resistant temperature of the substrate for 5 seconds to 5 hours.

The substrate heat-resistant temperature is the upper limit temperature at which the properties of the substrate can be substantially maintained.
For example, in the case of a plastic substrate such as a softening point and a devitrification temperature (normally 600 to 700 ° C.), for example, a glass transition point, a crystallization temperature, a decomposition point, and the like can be given.

By the drying and the heat treatment, an island-like, perforated film-like or mesh-like uneven layer, or a completely-covered uneven overcoat layer can be formed on the photocatalyst layer surface. This overcoat layer is composed of a matrix (or binder) of hydrophilic metal oxide fine particles and a hydrophilic metal oxide (derived from an organometallic compound or a compound containing a chlorosilyl group). The film form has an uneven shape in which the metal oxide matrix gathers around the metal oxide fine particles, and the photocatalytic layer is not completely covered by the island-shaped or perforated film-shaped or mesh-shaped uneven layer. ,
Partially exposed.

The article in which the metal oxide overcoat layer is formed on the surface of the photocatalyst layer in this manner has improved wettability with water, has a small contact angle of water droplets, and has anti-fog performance. Further, the contact angle does not easily increase even if the surface is slightly stained, and the antifogging property is maintained.

The above is mainly described as a method for forming the overcoat layer, in which a liquid containing a hydrolyzable / polycondensable organometallic compound capable of forming a hydrophilic metal oxide is added to a liquid containing a hydrophilic metal oxide fine particle. Described above, the method of forming a liquid by applying on the substrate on which the photocatalyst layer is formed has been described.
The uneven hydrophilic metal oxide layer can be formed by the following two methods (B) and (C).

(B) at least one selected from the group consisting of a hydrolyzable and polycondensable organometallic compound, a chlorosilyl group-containing compound and a hydrolyzate thereof, each of which can form a hydrophilic metal oxide. A method comprising applying a liquid obtained by adding an organic polymer compound to a solution containing the above, on a substrate on which the photocatalytic layer is formed, and decomposing and removing the organic polymer compound by heat treatment. (C) a liquid containing at least one selected from the group consisting of a hydrolyzable / polycondensable organometallic compound, a chlorosilyl group-containing compound, and a hydrolyzate thereof, each of which can form a hydrophilic metal oxide. A liquid obtained by adding organic polymer fine particles to a substrate on which the photocatalyst layer is formed, and decomposing and removing the organic polymer fine particles by heat treatment.

The above method (B) will be described. The method (A) in which the metal oxide overcoat layer in the method (B) uses the above-described liquid to which the hydrophilic metal oxide fine particles are added, except that the metal oxide fine particles are not added.
Is the same as

Although not containing metal oxide fine particles, at least one kind selected from the group consisting of polyethylene glycol, polypropylene glycol and polyvinyl alcohol is basically contained in the same overcoat-forming coating solution as in method (A). A liquid obtained by adding an organic polymer compound and dissolving them was coated and dried on the photocatalyst layer-formed substrate, and further heated at 350 to 650 ° C. for 5 minutes to 2 hours, and added. By decomposing the organic polymer compound, an island-like, perforated film-like or mesh-like irregular layer, or a completely covered irregular-shaped overcoat layer can be obtained.

The organic polymer compound is added in an amount of 30% by weight or more and 300% by weight or less based on the total solid content in terms of oxide in the overcoat-forming coating solution. If the addition amount is less than 30% by weight, the formation of irregularities is not sufficient, and it is not preferable because it cannot contribute to the improvement of hydrophilicity and antifogging / fouling performance. On the other hand, if the addition amount is more than 300% by weight, the mechanical strength of the film decreases, and a large amount of an organic polymer is required to produce a preferable overcoat with poor film formation efficiency, resulting in excessive cost. , Again not preferred.

As described in the method (A), also in the method (B), by adding a large amount of acid to the liquid containing the organometallic compound, the strength of the film after film formation is significantly increased, Even when drying at room temperature to 250 ° C.), a film that can sufficiently withstand practical use may be obtained.

The preferred composition of the coating liquid in which such an increase in film strength is observed (excluding the content of the organic polymer compound has been described) is the metal oxide calculated from the organometallic compound or its hydrolyzate. The concentration of the substance is 0.00001 to 0.6% by weight and the acid is 0.0001.
２．０2.0 mol / L, water content 0.001-20% by weight.

A preferred composition for coating the hydrophilic metal oxide layer with an opening reaching the photocatalyst layer is as follows:
The concentration of the metal oxide calculated from the organometallic compound or its hydrolyzate is 0.00001 to 0.3% by weight, the acid is 0.0001 to 1.0 mol / L, and the water content is 0.001 to 1.0 mol / L.
More preferably, the concentration of the metal oxide calculated from the organometallic compound or the hydrolyzate thereof is 0.001 to 0.1% by weight, and the acid is 0.01 to 10% by weight.
0.3 mol / L, water content is 0.001 to 3% by weight.
When a hydrophilic metal oxide layer having no opening reaching the photocatalyst layer is coated, the preferred composition is such that the concentration of the metal oxide calculated from the organometallic compound or the hydrolyzate thereof is 0.01 to 0.1. 6% by weight, acid is 0.1 to 2.0
Mol / L, water content is 0.01 to 20% by weight.

Hereinafter, the method (C) will be described.
The metal oxide overcoat layer in the method (C) is basically the same as the method (B) except that the organic polymer is not added.

[0076] The organic polymer fine particles are added to the same overcoat-forming coating solution as in the method (B), but do not contain an organic polymer, and are dispersed. It is applied on a layer-formed substrate, dried, and further heated at 350 to 650 ° C. for 5 minutes to 2 hours to decompose the added organic polymer fine particles to form an island-like, perforated film-like or network-like. An uneven layer or an overcoat layer having a completely covered uneven shape is obtained.

As the material of the organic polymer fine particles, any of a thermoplastic resin and a thermosetting resin can be used, and among them, an acrylic resin and a styrene resin can be preferably used.

The particle size of the organic polymer fine particles is not particularly limited, but is preferably 0.01 to 50 μm.
By using fine particles having a particle diameter in this range, an overcoat layer having a preferable form can be formed.

The amount of the organic polymer fine particles to be added to the overcoat forming liquid is from 5% by weight to 300% by weight based on the total solid content in terms of metal oxide in the liquid. If the addition amount is less than 5% by weight, the formation of irregularities is not sufficient, and it is not preferable because it cannot contribute to the improvement of hydrophilicity and antifogging and antifouling performance. On the other hand, if the addition amount is more than 300% by weight, a large amount of organic polymer fine particles is required to produce a preferable overcoat due to poor film-forming efficiency, so that the cost is too high, which is not preferable.

As described in the above methods (A) and (B), in the method (C) as well, by adding a large amount of acid to the solution containing the organometallic compound, the strength of the film after film formation is remarkably increased. In some cases, a film that can sufficiently withstand practical use even when dried at a low temperature (room temperature to 250 ° C.) may be obtained.

The preferred composition of the coating liquid in which such an increase in film strength is observed (excluding the content of the organic polymer fine particles has already been described) is the same as the composition described in the above method (B). Or the concentration of the metal oxide converted from the hydrolyzate,
0.00001-0.6% by weight, acid 0.0001-
2.0 mol / L, water content is 0.001 to 20% by weight. The preferred composition when coating the layer of the hydrophilic metal oxide with the opening reaching the photocatalyst layer, and the preferred composition when coating the layer of the hydrophilic metal oxide without the opening reaching the photocatalyst layer are the methods described above. The composition is the same as that described in (B).

The present invention can be applied to the surface of a substrate such as glass, ceramics, plastic or metal. More specifically, antifogging articles that prevent fogging and water droplet formation of the substrate, antifouling articles that prevent the surface from being soiled or that self-clean the surface, especially for construction, vehicles, optical components, industrial use, Suitable for products such as window glass, mirrors, lenses, heat exchanger fins for air conditioners, construction materials, biomaterials, film sheets and showcases, which are used for agriculture, daily necessities, housing and medical use. Has antifogging or antifouling performance.

[0083]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited to these embodiments.

Example 1, Comparative Example 1 [Formation of Alkali Barrier Layer (Silica Film)] Ethanol 9
3.8 parts by weight of 6.2 parts by weight and 3.8 parts by weight of a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., silica content: 10% by weight)
By stirring for 1 hour, a coating liquid for forming an alkali-blocking silica film was obtained.

A soda lime silicate glass plate (150 × 150 × 3 mm) which was polished and washed with a cerium oxide-based abrasive, further ultrasonically washed in pure water and dried was used.
The suspension was suspended vertically in an environment of 30 ° C. and 30% RH, and the coating solution for forming an alkali-blocking silica film was flowed from the upper end of the glass plate to coat the film on one surface of the glass plate (flow coating method). 100 pieces of this glass plate
After drying at 250 ° C. for 30 minutes, and further drying at 250 ° C. for 30 minutes, a heat treatment was performed in a 500 ° C. oven for 1 hour to obtain a glass substrate on which an alkali-blocking silica film having a thickness of about 30 nm was formed.

[Formation of Photocatalytic Layer (Titanium Oxide Thin Film)] Titanium tetraisopropoxide (Ti (OiPr) ₄ ) 8
With stirring to 5.6 g (0.3 mol), 60.3 g (0.6 mol) of acetylacetone (AcAc) was gradually added dropwise using a burette, and the mixture was stirred for about 1 hour to obtain stable Ti.
(AcAc) ₂ (OiPr) ₂ complex solution was obtained (mother liquor).
This mother liquor was diluted 1.5 times with ethanol to obtain a coating solution. After immersing the glass substrate on which the alkali-blocking silica film was formed in the coating solution, a film was formed at a pulling rate of 4.6 cm / min, and baked at 500 ° C. for 30 minutes. The obtained sample is referred to as Sample A (glass substrate / alkali blocking silica film / titanium oxide film: Comparative Example 1). As a result of analysis by X-ray diffraction, it was confirmed that the titanium oxide film of Sample A was an anatase crystal. The thickness of the titanium oxide thin film of Sample A is about 10
It was 0 nm. As a result of measurement by an atomic force microscope, the surface of the titanium oxide film of Sample A was a smooth surface having an arithmetic average roughness (Ra) of less than 0.2 nm and an average interval (Sm) of irregularities of 600 nm. Was.

[Formation of Overcoat Layer (Silica Film)]
An uneven silica overcoat layer was formed on Sample A by the method described below. Ethanol 98.8 g, hydrolysis condensation polymerization solution of ethyl silicate (trade name: HAS-
10, Colcoat Co., Ltd., silica content 10% by weight)
0.7 g, chain silica colloid (average diameter about 15 nm,
Average length about 170nm, Product name: Snowtex OU
P, manufactured by Nissan Chemical Industries, Ltd., solid content 15% by weight)
5 g were mixed and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid contained ethyl silicate in a ratio of 93% by weight relative to the silica fine particles in terms of silica for the binder. The sample A substrate was suspended vertically in an environment of 20 ° C. and 30% RH, the coating solution for forming the overcoat layer was flowed from the upper end of the substrate, and an overcoat film was coated on the photocatalytic layer of the substrate (flow Coating method). Thereafter, the sample B was heat-treated at 500 ° C. for 1 hour to obtain a sample B (glass substrate / alkali-blocking silica film /
Titanium oxide film / irregular silica overcoat layer: Example 1) was obtained. As a result of measurement with an atomic force microscope, the surface of Sample B was an uneven surface having an arithmetic average roughness (Ra) of 8 nm and an average interval (Sm) of unevenness of 30 nm. The average thickness of this silica overcoat layer determined by ESCA was about 15 nm.

[Evaluation of antifogging property] Samples A and B were
It is not exposed to direct sunlight but is indirectly bright with sunlight, and it is left in a room where people constantly come in and out, and the degree to which the surface becomes dirty and the anti-fog property is reduced is evaluated by the degree of cloudiness when exhalation is blown (Breath test). That is, the sample immediately after the surface is cleaned does not fog even when breath is blown, but when left indoors, the dirt component in the air is adsorbed on the sample surface and becomes cloudy by the breath test.
The time from the start of indoor standing until the start of fogging (antifogging maintenance time) was used as an index of antifogging maintenance. It can be said that the larger this value is, the higher the antifogging maintenance property is. The antifogging maintenance of these samples was evaluated according to Table 2 below.

Further, a sample having a lowered anti-fogging property due to being left indoors (having fogging in the above breath test) was subjected to xenon lamp light (each sample film having an ultraviolet intensity of 0.5 m) from the film surface.
W / cm ² : UV intensity meter “UVR” manufactured by Topcon Corporation
-2 / UD-36 ". ) Was continuously irradiated for one hour, and the magnitude of the decrease in the contact angle of the water droplet was used as an index of the anti-fogging recovery property. In addition, an ultraviolet ray of 0.5 mW / cm ² (340 to 39)
5 nm) The irradiation intensity corresponds to about 20% of the ultraviolet light intensity included in direct sunlight from outdoor sunlight at 35 ° north latitude at noon in winter, fine weather, and noon. If this UV light reduces the contact angle of the water drop, it can be said that the sample has a very good anti-fogging recovery property. Using a contact angle meter (“CA-DT” manufactured by Kyowa Interface Science Co., Ltd.), the contact angle with respect to a 0.4 mg water drop before and after the light irradiation for 1 hour was measured. The water drop contact angle factor defined by the value of (cosine of contact angle -1 after light irradiation for one hour-1) / (cosine of contact angle before light irradiation -1) is determined as shown in Table 3 below. The antifogging recovery property was evaluated in accordance with the following. It can be said that the smaller the water contact angle factor, the better the anti-fogging recovery property by light irradiation.

[0090]

[Table 2] Evaluation Anti-fogging retention period------------------------------------- ---------------◎ No fogging or slight unevenness continues for 9 days or more ○ 6 days to less than 9 days △ 3 days to less than 6 days × less than 3 days ─ ───────────────────────────

[0091]

[Table 3] ────────────────────────────── Anti-fogging recovery property Evaluation of water droplet contact angle factor (1 hour after light irradiation) Cosine of contact angle of waterdrop -1) / (Cosine of contact angle of waterdrop before irradiation -1) --------------------------------------------------------------------------- −− ◎ Less than 0.1 ○ 0.1 or more and less than 0.3 △ 0.3 or more and less than 0.5 × 0.5 or more ──────────────────── ──────────

Table 4 shows the results of various evaluations of Samples A (Comparative Example 1) and B (Example 1). It is clear that Sample B (Example 1) has significantly improved antifogging retention and antifogging recovery as compared to Sample A (Comparative Example 1).

[0093]

[Table 4] ─────────────────────────────────San antifogging Water drop contact angle Antifogging evaluation Antifoulingプ 維持 時間 ──────── ──────── ──────── ──────── 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日 日−−−−− Example 1B 12.3 0.09 ◎ ◎ ◎ 2C 9.5 0.15 ◎ ○ ○ 3 D 9.8 0.43 ◎ △ ○ 4 E 11.0 0.08 ◎ ◎ ◎ 5F 4.5 0.09 △ ◎ ○ 6 G 3.0 0.31 △ △ △ 7 H 8.0 0.05 ○ ◎ ◎ 8 I 9.7 0.15 ◎ ○ ◎ 9 J 15.3 0.03 ◎ ◎ ○ 10 K 14.7 0.30 ◎ ○ ○ 11 L 10.3 0.28 ◎ ○ ○ 12 N 38.3 0.07 ◎ ◎ ○ 13 O 38.2 0.01 ◎ ◎ ◎ ◎ 14 Q 9.5 0.20 ◎ ○ ◎ 15 R 20.5 0.25 ◎ ○ ○ 16 S 7.0 0.15 ○ ○ ○ 17 W 9.3 0.05 ◎ ◎ ◎ −−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−− Comparative Example 1 A 0.5 0.31 × Δ × 2 T 5.2 0.55 Δ × Δ 3 U 5.5 0.50 △ × △ 4 V 1.1 0.51 × △ △ ─────────────────────────────────

[Evaluation of antifouling property] The antifouling property was evaluated by the following outdoor exposure test. A sample plate was installed vertically in Itami City, Hyogo Prefecture, and an exposure test was conducted for 6 months from July to December in an environment simulating a vertical surface under the eaves where rainwater flows down the sample plate surface. Evaluation of contamination status of sample plate
The evaluation was made by visual evaluation according to the criteria in Table 5 below.

[0095]

[Table 5] ───────────────────────── Evaluation of antifouling property Pollution state −−−−−−−−−−−−−−−− ----------◎ Almost no noticeable dirt ○ Slightly dirt, thin streak is visible △ Dirt, streak is noticeable × Dirt is remarkable, streak is noticeable ─────────────────────────

Table 4 shows the results of evaluating the antifouling properties of Samples A (Comparative Example 1) and B (Example 1). It is clear that the antifouling property of Sample B (Example 1) is significantly improved as compared with Sample A (Comparative Example 1).

[Example 2] [Formation of overcoat layer (silica film)] An uneven silica overcoat layer was formed on sample A prepared in Example 1 by the method described below. 2-propanol 9
To 9.94 g, 0.3 g of a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., silica content: 10% by weight) and silica colloid (trade name:
IPA-ST, manufactured by Nissan Chemical Industries, Ltd., particle size 10
0.3 g of 20 nm, silica content 30% by weight)
The coating solution was obtained by stirring at room temperature for about 1 hour. Ethyl silicate was contained in the coating liquid at a ratio of 33% by weight relative to the silica fine particles in terms of silica for the binder. The coating solution was applied onto Sample A in the same manner as described in Example 1, and dried at 100 ° C. for 30 minutes to form a silica overcoat thin film. The sample thus obtained is designated as C (glass substrate / alkali blocking silica film / titanium oxide film / irregular silica overcoat thin film). As a result of measurement with an atomic force microscope, the surface of Sample C was an uneven surface having an arithmetic average roughness (Ra) of 12 nm and an average interval (Sm) of unevenness of 150 nm. The average thickness of this silica overcoat layer determined by ESCA was about 10 nm.

Table 4 shows the results of evaluating the various antifogging and antifouling performances of Sample C. It is clear that the antifogging and antifouling performance is improved as compared with Comparative Example 1.

[Example 3] [Formation of overcoat layer (alumina-silica film)] On sample A prepared in Example 1, a method described below was used.
An uneven overcoat layer was formed. Ethanol 99.
To 71 g, 0.25 g of tetraethoxysilane and an alumina colloid (trade name: alumina sol 520, manufactured by Nissan Chemical Industries, Ltd., particle diameter 40 to 50 nm, alumina content 20)
%) And stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid contained a binder derived from tetraethoxysilane at a weight ratio of 180% with respect to the alumina fine particles in terms of silica. Apply the same method as described in Example 1
An alumina-silica overcoat thin film was formed by performing a heat treatment at 50 ° C. for 30 minutes. The sample thus obtained is designated as D (glass substrate / alkali blocking silica film / titanium oxide film / irregular overcoat thin film). As a result of measurement with an atomic force microscope, the surface of the sample D was an uneven surface having an arithmetic average roughness (Ra) of 3 nm and an average interval (Sm) of unevenness of 300 nm. The average thickness of this overcoat layer measured by ESCA was about 10 nm.

Table 4 shows the results of evaluating the various antifogging and antifouling performances of Sample D. It is clear that the antifogging and antifouling performance is improved as compared with Comparative Example 1.

[Example 4] [Formation of overcoat layer (titania-silica film)] On sample A prepared in Example 1, a method described below was used.
An uneven overcoat layer was formed. Ethanol 99
1.34 g of tetrachlorosilane and titania colloid (trade name: CS-N, manufactured by Ishihara Sangyo Co., Ltd., particle size 30 to 60 nm, titania content 30% by weight) are added to 7.21 g.
45 g, chain silica colloid (average diameter: about 15 nm, average length: about 170 nm, trade name: Snowtex OUP,
1.0 g, solid content 15% by weight, manufactured by Nissan Chemical Industries, Ltd.
Was added and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid contained a binder derived from tetrachlorosilane at a ratio of 166% by weight in terms of silica, based on the total weight of the titania fine particles and the silica fine particles. It was applied in the same manner as described in Example 1 and dried at room temperature to form a titania-silica overcoat thin film. The sample thus obtained is referred to as Sample E (glass substrate / alkali blocking silica film / titanium oxide film / irregular overcoat thin film). As a result of measurement with an atomic force microscope, the surface of the sample E was an irregular surface having an arithmetic average roughness (Ra) of 35 nm and an average interval (Sm) of irregularities of 40 nm. The average thickness of this overcoat layer determined by ESCA was about 8 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample E. It is clear that it has excellent antifogging and antifouling performance.

[Example 5] [Formation of overcoat layer (silica film)] A mesh-like silica overcoat layer was formed on sample A prepared in Example 1 by the method described below. 2-propanol 9
0.03 g of a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., silica content: 10% by weight) and silica colloid (trade name: IPA-ST, Nissan Chemical Industry Co., Ltd.) in 9.94 g Made by company, particle size 1
(0-20 nm, silica content 30% by weight) was added and stirred at room temperature for about 1 hour to obtain a coating liquid. Ethyl silicate was contained in the coating liquid at a ratio of 33% by weight relative to the silica fine particles in terms of silica for the binder. Example 1
The coating solution was applied onto Sample A in the same manner as described above, and dried at 100 ° C. for 30 minutes to form a silica overcoat thin film. The sample thus obtained is designated as F (glass substrate / alkali blocking silica film / titanium oxide film / reticular silica overcoat thin film). As a result of measurement by an atomic force microscope, the surface of Sample F was an uneven surface having an arithmetic average roughness (Ra) of 5 nm and an average interval (Sm) of unevenness of 100 nm. Observation of the surface of Sample F with an electron microscope revealed that the silica overcoat had a mesh shape (average diameter of mesh holes was about 100 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 50% of the surface area of the photocatalyst layer was exposed without being coated with silica. The average thickness of this silica overcoat layer was determined by ESCA to be about 2n.
m.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample F. It is clear that the antifogging and antifouling performance is improved as compared with Comparative Example 1.

[Example 6] [Formation of overcoat layer (alumina-silica film)] On the sample A prepared in Example 1, a method described below was used.
A reticulated overcoat layer was formed. Ethanol 99.
To 71 g, 0.25 g of tetraethoxysilane and an alumina colloid (trade name: alumina sol 520, manufactured by Nissan Chemical Industries, Ltd., particle diameter 40 to 50 nm, alumina content 20)
%) And stirred at room temperature for about 1 hour to obtain a stock solution. This stock solution was diluted 100-fold with ethanol to obtain a coating solution. In the coating solution, a binder derived from tetraethoxysilane is converted into silica,
It was contained at a weight ratio of 180% to the alumina fine particles. Coating in the same manner as described in Example 1,
By heat treatment at 250 ° C. for 30 minutes, alumina
A silica overcoat thin film was formed. The sample thus obtained is referred to as G (glass substrate / alkali blocking silica film / titanium oxide film / network overcoat thin film). As a result of measurement with an atomic force microscope, the surface of Sample G was an uneven surface having an arithmetic average roughness (Ra) of 0.6 nm and an average interval (Sm) of unevenness of 300 nm. Observation of the surface of Sample G with an electron microscope revealed that the overcoat had a mesh shape (average diameter of mesh holes was about 1000 nm), and the underlying photocatalytic layer was observed. It was found by using the image analysis technique that about 80% of the surface area of the photocatalyst layer was exposed without being covered with the overcoat layer. Further, when the average thickness of the overcoat layer was estimated from the coating solution concentration, it was about 0.1 nm.

Table 4 shows the results of evaluating the various antifogging and antifouling performances of Sample G. It is clear that the antifogging and antifouling performance is improved as compared with Comparative Example 1.

[Example 7] [Formation of overcoat layer (zirconia-silica film)]
A reticulated overcoat layer was formed on Sample A prepared in Example 1 by the method described below. Alcohol (ethanol 85.5% by weight, 1-propanol 9.6)
% By weight, 4.9% by weight of 2-propanol, trade name: AP
-7, manufactured by Nippon Kaseihin Co., Ltd.) 99.33 g of a hydrolytic polycondensation solution of ethyl silicate (trade name: HAS-10,
Colcoat Co., Ltd., silica content 10% by weight).
50 g and zirconia colloid (trade name: NZS-30)
A, manufactured by Nissan Chemical Industries, Ltd., particle size 40-50 nm,
0.17 g of zirconia (30% zirconia content) was added, and the mixture was stirred at room temperature for about 1 hour to prepare a stock solution. Separately, a solution was prepared by dissolving 0.01 g of aluminum chloride in 500 g of ethanol, and the stock solution was diluted 5-fold with this solution to obtain a coating solution. In the coating liquid, a binder derived from ethyl silicate was contained in a ratio of 98% by weight relative to zirconia fine particles in terms of silica. Coating was performed in the same manner as described in Example 1, and 500
By heat-treating at 1 ° C. for 1 hour, a zirconia-silica overcoat thin film was formed. The sample thus obtained is designated as H (glass substrate / alkali-blocking silica film / titanium oxide film / network overcoat thin film).
As a result of measurement with an atomic force microscope, the surface of the sample H was an uneven surface having an arithmetic average roughness (Ra) of 8 nm and an average interval (Sm) of unevenness of 80 nm. Observation of the surface of Sample H with an electron microscope revealed that the overcoat was mesh-like (average diameter of mesh holes was about 90 n).
m), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 50% of the surface area of the photocatalyst layer was exposed without being covered with the overcoat. The average thickness of this overcoat layer determined by ESCA was about 2 nm.

Table 4 shows the results of evaluating various antifogging and antifouling properties of Sample H. It is clear that it has excellent antifogging and antifouling performance.

[Example 8] [Formation of overcoat layer (titania-silica film)] On the sample A prepared in Example 1, a method described below was used.
A perforated film-like overcoat layer was formed. 1.34 g of tetrachlorosilane and 0.45 g of titania colloid (trade name: CS-N, manufactured by Ishihara Sangyo Co., Ltd., particle diameter 30 to 60 nm, titania content 30% by weight) are added to 498.21 g of ethanol, and iron (III) chloride 0 0.002 g,
The coating liquid was obtained by stirring at room temperature for about 1 hour. In the coating solution, a binder derived from tetrachlorosilane was converted to silica in a weight ratio of 35 to the titania fine particles.
It was contained at a rate of 1%. It was applied in the same manner as described in Example 1 and dried at room temperature to form a titania-silica overcoat thin film. The sample thus obtained is referred to as I (glass substrate / alkali blocking silica film / titanium oxide film / perforated film-like overcoat thin film). As a result of measurement with an atomic force microscope, the surface of Sample I was an uneven surface having an arithmetic average roughness (Ra) of 30 nm and an average interval (Sm) of unevenness of 50 nm. When the surface of Sample I was observed with an electron microscope, the overcoat was in the form of a film with holes (average diameter of holes: about 40 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 30% of the surface area of the photocatalyst layer was exposed without being covered with the overcoat. The average thickness of this overcoat layer was found to be about 10 nm by ESCA.
Met.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample I. It is clear that it has excellent antifogging and antifouling performance.

[Example 9] [Overcoat layer (silica film added with vanadium compound)]
Formation of a network-like silica overcoat layer on Sample A prepared in Example 1 by the method described below.
0.15 g of vanadyl acetylacetone is added to 0.12 of concentrated hydrochloric acid.
g and alcohol (trade name: AP-7, manufactured by Nippon Kaseihin Co., Ltd.) were added and dissolved to obtain a vanadium-added liquid. 0.14 g of tetrachlorosilane and 1.46 g of the above vanadium-added solution were added to 98.40 g of alcohol (trade name: AP-7, manufactured by Nippon Kaseihin Co., Ltd.), and the mixture was stirred at room temperature for about 1 hour to obtain a coating solution. . Example 1
The coating was performed in the same manner as described above, and heat treatment was performed at 450 ° C. for 1 hour to form a vanadium compound-added silica overcoat thin film. The sample thus obtained is referred to as J (glass substrate / alkali blocking silica film / titanium oxide film / vanadium compound-added silica overcoat thin film). As a result of measurement by an atomic force microscope, the surface of Sample J was an uneven surface having an arithmetic average roughness (Ra) of 50 nm and an average interval (Sm) of unevenness of 50 nm. Observation of the surface of Sample J with an electron microscope revealed that the overcoat had a mesh shape (average diameter of mesh holes was about 30 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 40% of the surface area of the photocatalyst layer was exposed without being covered with the overcoat. The average thickness of this overcoat layer determined by ESCA was about 7 nm.

Table 4 shows the results of evaluating various antifogging and antifouling properties of Sample J. It is clear that it has excellent antifogging and antifouling performance.

Example 10 [Formation of Overcoat Layer (Silica Film): Addition Method of Polymer Fine Particles] To 3.00 g of tetraethoxysilane, 76.53 g of ethanol and 0.70 g of 0.1N hydrochloric acid were added to prepare about 1%.
The mixture was stirred for an hour, and further diluted by adding 1650 g of ethanol. An aqueous dispersion of polymethyl methacrylate fine particles was added to this solution (trade name: MA03W, manufactured by Nippon Shokubai Chemical Co., Ltd., average particle size 0.03 μm, fine particle content 10% by weight).
5.0 g was added and mixed for 1 hour to obtain a coating solution. The coating liquid contained polymethyl methacrylate fine particles at a ratio of about 58% by weight relative to a binder (in terms of silica) derived from tetraethoxysilane.

The sample A prepared in Example 1 was spin-coated (1000 rpm, 10 seconds, liquid amount 4 m).
The film was formed so as to have a silica film thickness of 30 nm according to 1) and dried at room temperature. In order to burn the acrylic fine particles and densify the silica film, it was further baked at 550 ° C. for 1 hour to form a silica overcoat thin film. The sample thus obtained is designated as K (glass substrate / alkali blocking silica film / titanium oxide film / irregular silica overcoat thin film). As a result of measurement with an atomic force microscope,
The surface of Sample K was an uneven surface having an arithmetic average roughness (Ra) of 30 nm and an average interval (Sm) of unevenness of 30 nm. The average thickness of this overcoat layer determined by ESCA was about 25 nm.

Table 4 shows the results of evaluating the various antifogging and antifouling performances of Sample K. It is clear that it has excellent antifogging and antifouling performance.

Example 11 [Formation of Overcoat Layer (Silica Film): Method for Adding Polymer Fine Particles] To 3.00 g of tetraethoxysilane, 76.53 g of ethanol and 0.70 g of 0.1N hydrochloric acid were added to prepare about 1%.
The mixture was stirred for an hour, and further diluted by adding 1650 g of ethanol. Acrylic fine particles (trade name: GL)
0.17 g of a cross-linked acrylic fine particle having a particle size of 0.1 μm (manufactured by Soken Chemical Co., Ltd.) was added and dispersed with a homogenizer to obtain a coating liquid. In the coating liquid, the acrylic fine particles are about 2 parts by weight relative to the binder (in terms of silica) derived from tetraethoxysilane.
It was contained at a rate of 0%.

The sample A prepared in Example 1 was spin-coated (1000 rpm, 10 seconds, liquid amount 4 m).
The film was formed so as to have a silica film thickness of 30 nm according to 1) and dried at room temperature. In order to burn the acrylic fine particles and densify the silica film, firing was further performed at 600 ° C. to form a silica overcoat thin film. The sample thus obtained is referred to as L (glass substrate / alkali blocking silica film / titanium oxide film / perforated film-like silica overcoat thin film). As a result of measurement with an atomic force microscope, the surface of the sample L had an arithmetic average roughness (Ra) of 15 n.
m and the average interval (Sm) of the irregularities was 200 nm. In addition, sample L
As a result, the overcoat was in the form of a film with holes (average diameter of holes: about 100 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 15% of the surface area of the photocatalyst layer was exposed without being covered with the overcoat. Also, ESCA
As a result, the average thickness of this overcoat layer was determined to be about 20 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample L. It is clear that it has excellent antifogging and antifouling performance.

[Example 12] [Formation of alkali barrier film (silica-zirconia thin film)]
5 parts by weight of zirconium butoxide was added to ethyl acetoacetate 1
The mixture was stirred at 30 ° C. for 2 hours. This is designated as solution A. Separately, 50 parts by weight of tetraethoxysilane, 2
-1000 parts by weight of propanol, 2.5 parts by weight of 1N nitric acid and 50 parts by weight of water were added, and the mixture was stirred at 30 ° C for 2 hours. This is designated as solution B. The solution A and the solution B were mixed and agitated and cured at 50 ° C. for 3 hours and further at 30 ° C. for 1 day to obtain a sol solution for an alkali barrier film.

A soda lime silicate glass plate (65 mm × 150 mm × 3 mm) which has been subjected to surface polishing and washing with a cerium oxide-based abrasive, further subjected to ultrasonic washing in pure water and dried.
Was immersed in the sol solution for an alkali barrier film, and the sol was applied by pulling up the glass plate at a speed of 10 cm / min. Then, it is dried at room temperature for several minutes,
Heat treatment was performed for a time to obtain a glass plate on which a silica-zirconia thin film (silica 92% by weight, zirconia 8% by weight) with a thickness of about 30 nm was formed.

[Formation of Vanadium Compound Added Titanium Oxide Fine Particle Dispersed Silica Thin Film] Next, a method of coating a vanadium added titanium oxide fine particle dispersed silica thin film by a sol-gel method will be described. 0.79 g of 35% hydrochloric acid and 8.21 g of alcohol (trade name: AP-7, manufactured by Nippon Kasei Chemical Co., Ltd.) were added to 1.00 g of acetylacetone vanadyl and dissolved to prepare a vanadium-added liquid. Dispersion of 0.34 g of tetrachlorosilane and 2.00 g of titania fine particles (trade name: ST-K01, manufactured by Ishihara Sangyo Co., Ltd.) in 95.00 g of alcohol (trade name: AP-7, manufactured by Nippon Kasei) And 2.66 g of the vanadium-added solution were added and mixed at room temperature for about 2 hours to obtain a coating solution. Using this coating solution, a film was formed on the soda lime silicate glass substrate with the silica-zirconia film by the flow coating method described in Example 1,
By drying at room temperature and heat-treating at 500 ° C for 1 hour,
Sample M (Glass substrate / Silica-zirconia thin film / Vanadium compound added titanium oxide fine particle dispersed silica thin film)
I got

The vanadium oxide-added titanium oxide fine particle-dispersed silica thin film of Sample M has a thickness of about 60 nm,
It has a composition of 39% by weight of silicon oxide, 39% by weight of titanium oxide, and 22% by weight of a vanadium compound (in terms of V ₂ O ₅ ).
/Ti=0.5 (atomic ratio).

[Formation of Overcoat Layer (Silica Film)]
A silica overcoat layer was formed on Sample M by the method described below. 98.9 g of ethanol, a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-1)
0, manufactured by Colcoat Co., Ltd., silica content 10% by weight).
5 g, 0.6 g of chain silica colloid (average diameter: about 15 nm, average length: about 170 nm, trade name: Snowtex OUP, manufactured by Nissan Chemical Industries, Ltd., solid content: 15% by weight) are mixed, and the mixture is mixed at room temperature for about 1 hour. The coating liquid was obtained by stirring. In the coating liquid, ethyl silicate was contained in a ratio of about 56% by weight relative to the silica fine particles in terms of silica for the binder.

In the same manner as the flow coating method described in Example 1, the surface of the sample M was coated with the above coating solution, and heat-treated at 500 ° C. for 1 hour.
(Glass substrate / silica-zirconia thin film / vanadium oxide-added titanium oxide fine particle-dispersed silica thin film / uneven silica overcoat layer: Example 12) was obtained. As a result of the measurement using an atomic force microscope, the surface of the sample N had an arithmetic average roughness (Ra) of 40 nm and an average interval of unevenness (Sm).
Had an uneven surface of 70 nm. Also, ESC
The average thickness of this silica overcoat layer was determined by A to be about 15 nm. Sample N (Example 1
Table 4 shows the evaluation results of the various antifogging and antifouling performances of 2). It is apparent that the formation of the uneven silica overcoat layer has better antifogging and antifouling properties.

[Example 13] [Formation of overcoat layer (silica film)] On sample M obtained in Example 12, a silica overcoat layer was formed by the method described below. Ethanol 99.1
g, ethyl silicate hydrolytic condensation polymerization solution (trade name: H
0.7 g of AS-10, manufactured by Colcoat Co., Ltd., silica content 10% by weight, colloidal silica colloid (average diameter about 15 n)
m, average length about 170 nm, trade name: Snowtex O
UP, manufactured by Nissan Chemical Industries, Ltd., solid content 15% by weight)
0.2 g was mixed and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid contained ethyl silicate in a ratio of 232% by weight relative to the silica fine particles in terms of silica for the binder.

In the same manner as in the flow coating method described in Example 1, the surface of Sample M was coated with the above coating solution, and heat-treated at 500 ° C. for 1 hour.
(Glass substrate / silica-zirconia thin film / vanadium oxide-added titanium oxide fine particle-dispersed silica thin film / silica overcoat layer: Example 13) was obtained. As a result of measurement with an atomic force microscope, the surface of sample O was found to have an arithmetic average roughness (R
a) is 30 nm, and the average interval (Sm) of the irregularities is 8
The uneven surface had a thickness of 5 nm. When the surface of Sample O was observed with an electron microscope, the silica overcoat was in the form of a film with holes (average diameter of holes: about 30 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 30% of the surface area of the photocatalyst layer was exposed without being coated with silica. Also, E
The average thickness of this silica overcoat layer determined by SCA was about 10 nm. Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample O (Example 13). It is apparent that the formation of the perforated film-like silica overcoat layer has more excellent antifogging and antifouling properties.

Example 14 [Formation of Alkali Barrier Film (Silica-Titania Thin Film)] 2.8 parts by weight of titanium isopropoxide was added to 2 parts by weight of acetylacetone, followed by stirring at 30 ° C. for 2 hours. This is designated as solution A. Separately, 50 parts by weight of tetraethoxysilane,
1000 parts by weight of 2-propanol, 2.5 parts by weight of 1N nitric acid, and 50 parts by weight of water were added, and the mixture was stirred at 30 ° C. for 2 hours. This is designated as solution B. The solution A and the solution B were mixed and agitated and cured at 50 ° C. for 3 hours and further at 30 ° C. for 1 day to obtain a sol solution for an alkali barrier film.

A soda lime silicate glass plate (65 mm × 150 mm × 3 mm) which has been subjected to surface polishing and washing with a cerium oxide-based abrasive and further subjected to ultrasonic washing in pure water and dried.
Was immersed in the sol solution for an alkali barrier film, and the sol was applied by pulling up the glass plate at a speed of 10 cm / min. Then, it is dried at room temperature for several minutes,
Heat treatment was performed for a time to obtain a glass plate on which a silica-titania thin film (96% by weight of silica, 4% by weight of titania) having a thickness of about 30 nm was formed.

[Formation of Photocatalyst Film (Silica Thin Film Dispersed with Titania Fine Particles)] Commercially available photocatalyst coating solution ST-K03
(Made by Ishihara Sangyo Co., Ltd., titanium oxide fine particle content: 5% by weight, inorganic binder: 5% by weight) was diluted 4 times by weight with ethanol. This solution was applied onto a glass plate on which the silica-titania thin film was formed by spin coating (1).
500 rpm, 10 seconds, liquid volume 4 ml)
Heat treatment was performed at 0 ° C. for 1 hour to form a photocatalytic thin film having a thickness of about 60 nm. As a result of chemical analysis, it was confirmed that this photocatalytic thin film was composed of about 50% by weight of titanium oxide and about 50% by weight of silicon oxide.

The obtained sample was designated as Sample P (glass substrate / alkali-blocking silica-titania thin film / titanium oxide fine particle dispersed silica thin film). As a result of analysis by X-ray diffraction, it was confirmed that the titanium oxide film of Sample P was an anatase crystal. As a result of the measurement with an atomic force microscope, the surface of the sample P had an arithmetic average roughness (Ra) of 2n.
m and the average interval (Sm) of the irregularities was 60 nm.

[Formation of Overcoat Layer (Silica Film)]
On the sample P, the island-like silica overcoat layer described in Example 1 was formed by the method described in Example 1. The obtained sample is referred to as Sample Q (glass substrate / alkali-blocking silica-titania thin film / titanium oxide fine particle-dispersed silica thin film / island silica overcoat layer: Example 14). As a result of measurement with an atomic force microscope, the surface of the sample Q was an uneven surface having an arithmetic average roughness (Ra) of 15 nm and an average interval (Sm) of unevenness of 50 nm. Observation of the surface of Sample Q with an electron microscope revealed that the silica overcoat was island-shaped (average diameter of the bottom of the island was about 50 n).
m), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 40% of the surface area of the photocatalyst layer was exposed without being covered with the silica overcoat. The average thickness of this silica overcoat layer determined by ESCA was about 5 nm.

Table 4 shows the results of the various evaluations of Sample Q (Example 14). It is clear that Sample Q (Example 14) has excellent antifogging retention and antifogging recovery properties.

[Example 15] [Formation of overcoat layer (silica film): method of adding organic polymer] An uneven silica overcoat layer was formed on sample A prepared in Example 1 by the following method. . 100 g of ethanol, 5.4 g of a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., silica content: 10% by weight), and 1.2 g of polyethylene glycol (average molecular weight: 1000) were mixed, and the mixture was stirred at room temperature. About 1
The coating solution was obtained by stirring for hours. In the coating liquid, polyethylene glycol was contained at a ratio of about 222% by weight with respect to the binder (in terms of silica) derived from ethyl silicate. The coating liquid for forming the overcoat layer was coated on the sample A substrate in the same manner as described in Example 1. Thereafter, heat treatment was performed at 520 ° C. for 1 hour to obtain Sample R (glass substrate / alkali blocking silica film / titanium oxide film / irregular silica overcoat layer). As a result of measurement by an atomic force microscope, the surface of the sample R had an arithmetic average roughness (Ra) of 70 nm and an average interval of irregularities (S
m) had an uneven surface of 50 nm. Also, E
The average thickness of this silica overcoat layer determined by SCA was about 45 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample R. It is clear that it has excellent antifogging and antifouling performance.

[Example 16] [Formation of overcoat layer (silica film): method of adding organic polymer] A film-like silica overcoat layer having a hole was formed on sample A prepared in Example 1 by the following method. Was formed. 280 g of ethanol, 1.4 g of a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., silica content 10% by weight), and 0.3 g of polyethylene glycol (average molecular weight 400) were mixed, and the mixture was mixed at room temperature. The coating liquid was obtained by stirring for about 1 hour.
In the coating liquid, polyethylene glycol was contained in a ratio of about 214% by weight based on the binder (in terms of silica) derived from ethyl silicate. The coating liquid for forming the overcoat layer was coated on the sample A substrate in the same manner as described in Example 1. Then, by heat treatment at 520 ° C for 1 hour,
Sample S (glass substrate / alkali blocking silica film / titanium oxide film / perforated film-like silica overcoat layer) was obtained. As a result of measurement with an atomic force microscope, the surface of the sample S was an uneven surface having an arithmetic average roughness (Ra) of 70 nm and an average interval (Sm) of unevenness of 150 nm. When the surface of Sample S was observed with an electron microscope, the silica overcoat was in the form of a film with holes (average diameter of holes: about 50 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 60% of the surface area of the photocatalyst layer was exposed without being coated with silica. The average thickness of this silica overcoat layer determined by ESCA was about 8 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample S. It is clear that it has excellent antifogging and antifouling performance.

[Example 17] [Formation of overcoat layer (silica film)] An island-like silica overcoat layer was formed on the sample A prepared in Example 1 by the method described below. 280 g of ethanol,
Ethyl silicate hydrolytic condensation polymerization solution (trade name: HAS
-10, manufactured by Colcoat Co., Ltd., silica content 10% by weight)
0.7 g, chain silica colloid (average diameter about 15 nm,
Average length about 170nm, Product name: Snowtex OU
P, manufactured by Nissan Chemical Industries, Ltd., solid content 15% by weight)
5 g were mixed and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid contained ethyl silicate in a ratio of 93% by weight relative to the silica fine particles in terms of silica for the binder. The sample A substrate was suspended vertically in an environment of 20 ° C. and 30% RH, the coating solution for forming the overcoat layer was flowed from the upper end of the substrate, and an overcoat film was coated on the photocatalytic layer of the substrate (flow Coating method). Thereafter, the sample W was subjected to a heat treatment at 500 ° C. for 1 hour to obtain a sample W (glass substrate / alkali-blocking silica film /
Titanium oxide film / insular silica overcoat layer: Example 1) was obtained. As a result of measurement with an atomic force microscope, the surface of the sample W was an uneven surface having an arithmetic average roughness (Ra) of 10 nm and an average interval (Sm) of unevenness of 50 nm. When the surface of the sample W was observed with an electron microscope, the silica overcoat was in an island shape (average diameter of the bottom surface of the island was about 50 nm), and the underlying photocatalytic layer was observed. It was found by using an image analysis technique that about 40% of the surface area of the photocatalyst layer was exposed without being coated with silica. The average thickness of this silica overcoat layer determined by ESCA was about 5 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample W. It is clear that it has excellent antifogging and antifouling performance.

[Comparative Example 2] [Formation of smooth overcoat layer (silica film)] Example 1
A smooth silica overcoat layer was formed on the sample A prepared in the above by the method described below. Ethanol 140
g, ethyl silicate hydrolytic condensation polymerization solution (trade name: H
1.4 g of AS-10 (manufactured by Colcoat Co., Ltd., silica content: 10% by weight) was mixed and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid for forming the overcoat layer was coated on the sample A substrate in the same manner as described in Example 1. After that, 500 ° C
For 1 hour to obtain Sample T (glass substrate / alkali blocking silica film / titanium oxide film / smooth silica overcoat layer). As a result of measurement with an atomic force microscope, the surface of the sample T had an arithmetic average roughness (Ra) of 0.2 nm or less and an average interval (Sm) of irregularities of 4 nm.
It had a smooth surface of not less than 00 nm. Also, ES
The average thickness of this silica overcoat layer was determined by CA to be about 10 nm.

Table 4 shows the results of evaluating various antifogging and antifouling properties of Sample T. It is clear that the antifogging and antifouling performance is low as compared with the examples.

[Comparative Example 3] [Formation of smooth overcoat layer (silica film)] Example 1
A smooth silica overcoat layer was formed on the sample A prepared in the above by the method described below. Ethanol 280
g, ethyl silicate hydrolytic condensation polymerization solution (trade name: H
1.4 g of AS-10 (manufactured by Colcoat Co., Ltd., silica content: 10% by weight) was mixed and stirred at room temperature for about 1 hour to obtain a coating liquid. The coating liquid for forming the overcoat layer was coated on the sample A substrate in the same manner as described in Example 1. After that, 500 ° C
For 1 hour to obtain Sample U (glass substrate / alkali blocking silica film / titanium oxide film / smooth silica overcoat layer). As a result of measurement with an atomic force microscope, the surface of the sample U had an arithmetic average roughness (Ra) of 0.2 nm or less and an average interval (Sm) of irregularities of 4 nm.
It had a smooth surface of not less than 00 nm. When the surface of Sample U was observed with an electron microscope, the silica overcoat completely covered the photocatalyst film, and the underlying photocatalyst layer was not observed. The average thickness of this silica overcoat layer was determined by ESCA to be about 5 n
m.

Table 4 shows the results of evaluating the various antifogging and antifouling performances of Sample U. It is clear that the antifogging and antifouling performance is low as compared with the examples.

[Comparative Example 4] Instead of forming the overcoat layer (silica film) in Example 1, a vacuum deposition method (deposition rate: 0.5 nm / sec, oxygen partial pressure: 2.0 × 10 −4)
torr, substrate temperature 200 ° C.), except that an overcoat layer (silica film) having a thickness of 15 nm is formed.
In the same manner as in Example 1, Sample V (glass substrate / alkali blocking silica film / titanium oxide film / porous silica overcoat layer) was obtained. As a result of measurement by an atomic force microscope, the surface of the sample V had an arithmetic average roughness (Ra) of 3 nm.
And the average interval (Sm) of the irregularities was 150 nm. Observation of the surface of Sample V with an electron microscope revealed that the silica overcoat was a porous film having independent pores (average diameter of independent pores was about 0.5 nm).
, And the underlying photocatalytic layer was not observed. It was found by using an image analysis technique that about 5% of the surface area of the photocatalyst layer was exposed without being coated with silica.
The average thickness of this silica overcoat layer determined by ESCA was about 15 nm.

Table 4 shows the results of evaluating various antifogging and antifouling performances of Sample V. It is clear that the antifogging and antifouling performance is not good.

[0145]

As described above, it is clear that the glass article of the present invention has excellent antifogging and antifouling performance and its maintainability, and also has good mechanical durability. It can be suitably used for applications such as automotive, architectural and optical applications.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/00 C09D 5/00 Z 185/00 185/00 C09K 3/18 C09K 3/18

Claims (40)

[Claims] 1. An article having a hydrophilic surface, comprising a substrate, a photocatalyst layer coated thereon, and a layer of a hydrophilic metal oxide coated on the photocatalyst layer, wherein the article has a hydrophilic metal oxide. An article having a hydrophilic surface, wherein the layer of the article comprises fine particles of a hydrophilic metal oxide and a binder of the hydrophilic metal oxide, and the article has irregularities on its surface. 2. The article having a hydrophilic surface according to claim 1, wherein the layer of the hydrophilic metal oxide has an opening reaching the photocatalytic layer. 3. An article having a hydrophilic surface comprising a substrate, a photocatalyst layer coated thereon, and a layer of a hydrophilic metal oxide coated on the photocatalyst layer, wherein the article has an arithmetic operation. An article having a hydrophilic surface, characterized by having irregularities on the surface having an average roughness (Ra) of 0.5 to 100 nm and an average interval (Sm) of irregularities of 4 to 300 nm. 4. The article having a hydrophilic surface according to claim 3, wherein the hydrophilic metal oxide layer contains hydrophilic metal oxide fine particles and a hydrophilic metal oxide binder. 5. The article having a hydrophilic surface according to claim 3, wherein the layer of the hydrophilic metal oxide has an opening reaching the photocatalytic layer. 6. A substrate, a photocatalyst layer coated thereon, and a layer of a hydrophilic metal oxide coated on the photocatalyst layer with an opening reaching the photocatalyst layer,
In an article having a hydrophilic surface, the article has irregularities on its surface, and 10% to 90% of the surface area of the photocatalytic layer.
An article having a hydrophilic surface, characterized in that a surface portion of the above faces an opening of the hydrophilic metal oxide layer. 7. The article having a hydrophilic surface according to claim 6, wherein said hydrophilic metal oxide layer contains hydrophilic metal oxide fine particles and a hydrophilic metal oxide binder. 8. The unevenness has an arithmetic mean roughness (Ra) of 0.5.
The article having a hydrophilic surface according to claim 1, 6 or 7, wherein the article has a thickness of 5 to 100 nm and an average interval (Sm) of unevenness of 4 to 300 nm. 9. The article having a hydrophilic surface according to claim 2, wherein a surface portion of 10 to 90% of a surface area of the photocatalyst layer faces an opening of the hydrophilic metal oxide layer. 10. The article having a hydrophilic surface according to claim 1, wherein the hydrophilic metal oxide layer contains the hydrophilic metal oxide fine particles in an amount of 5 to 95% by weight. 11. The fine particles of the hydrophilic metal oxide according to claim 1,
The article having a hydrophilic surface according to claim 1, 2, 4, 7, or 10 having a particle size of 300 nm. 12. The hydrophilic metal oxide binder is contained in an amount of 5 to 400% by weight based on the weight of the hydrophilic metal oxide fine particles.
An article having a hydrophilic surface as described in the above. 13. The hydrophilic metal oxide fine particles are fine particles of at least one oxide selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, molybdenum oxide, vanadium oxide and titanium oxide. The binder is at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, molybdenum oxide, vanadium oxide and amorphous titanium oxide. An article having a hydrophilic surface according to any one of claims, 7, 10 to 12. 14. The method according to claim 1, wherein the hydrophilic metal oxide fine particles contain at least chain silica fine particles.
An article having a hydrophilic surface according to any one of items 10 to 13. 15. The method according to claim 15, wherein the chain silica fine particles are 10-20.
3. The method of claim 1, wherein the diameter is between about 40 nm and about 300 nm.
An article having the hydrophilic surface according to 4. 16. The method according to claim 16, wherein the hydrophilic metal oxide layer has a thickness of 0.01.
The article having a hydrophilic surface according to any one of claims 1 to 15, having an average thickness of ５０50 nm. 17. The photocatalyst layer according to claim 1, wherein the titanium oxide comprises 30 to
The article having a hydrophilic surface according to any one of claims 1 to 16, which contains 100%. 18. The photocatalytic layer according to claim 1, wherein the titanium oxide has a thickness of 30 to
The article having a hydrophilic surface according to any one of claims 1 to 16, which contains 70% by weight. 19. The article having a hydrophilic surface according to claim 17, wherein the titanium oxide is fine particles having a particle size of 5 to 100 nm. 20. The base material on which the photocatalyst layer is formed, wherein (1-
1) a hydrolyzable / polycondensable organometallic compound of at least one metal selected from the group consisting of silicon, aluminum, titanium, zirconium, molybdenum, vanadium and cerium, and / or a hydrolyzate thereof; -2) at least one selected from the group consisting of chlorosilyl group-containing compounds and / or hydrolysates thereof, and (2) silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, molybdenum oxide, vanadium oxide and oxidation. A solution containing at least one type of metal oxide fine particles selected from the group consisting of titanium is applied and dried, and then, if necessary, heated to form a hydrophilic metal oxide having an uneven surface on the photocatalytic layer. A method for producing an article having a hydrophilic surface that forms a layer of an object. 21. The hydrophilic metal oxide layer has an arithmetic average roughness (Ra) of 0.5 to 100 nm and an average interval (Sm) of unevenness of 4 to 300 nm. Item 21. A method for producing an article having a hydrophilic surface according to Item 20. 22. The liquid contains the hydrolyzable / polycondensable organometallic compound or its hydrolyzate, the metal oxide fine particles and an acid, and the organic metal compound or its hydrolyzate and the metal oxide The total of the fine particles is 0.00001 to 0.6% by weight in terms of metal oxide, and the acid is 0.1% by weight.
22. The method for producing an article having a hydrophilic surface according to claim 20, wherein the content is 0001 to 2.0 mol / L and the water content is 0.001 to 20% by weight. 23. The liquid contains the hydrolyzable / polycondensable organometallic compound or its hydrolyzate, the metal oxide fine particles and an acid, and the organic metal compound or its hydrolyzate and the metal oxide The total of the fine particles is 0.01 to 0.6% by weight in terms of metal oxide, and the acid is 0.1 to 0.6% by weight.
22. The method for producing an article having a hydrophilic surface according to claim 20, wherein 2.0 mol / L and 0.01 to 20% by weight of water are contained. 24. The hydrophilic metal oxide layer is coated with an opening reaching the photocatalyst layer.
Or a method for producing an article having a hydrophilic surface according to 21. 25. The liquid containing the hydrolyzable / polycondensable organometallic compound or its hydrolyzate, the metal oxide fine particles and an acid, wherein the organometallic compound or its hydrolyzate and the metal oxide The total of the fine particles is 0.00001 to 0.3% by weight in terms of metal oxide, and the acid is 0.1 to 0.3% by weight.
The method for producing an article having a hydrophilic surface according to claim 24, wherein the article contains 0001 to 1.0 mol / L and 0.001 to 10% by weight of water. 26. The article having a hydrophilic surface according to claim 20, wherein the metal oxide fine particles are contained in an amount of 10 to 80% by weight based on the total solid content in the liquid. Manufacturing method. 27. The method for producing an article having a hydrophilic surface according to claim 20, wherein at least a part of the metal oxide fine particles is a colloidal silica colloid. 28. The substrate on which the photocatalyst layer has been formed is provided with (1-
1) a hydrolyzable / polycondensable organometallic compound of at least one metal selected from the group consisting of silicon, aluminum, titanium, zirconium, molybdenum, vanadium and cerium, and / or a hydrolyzate thereof; -2) at least one member selected from the group consisting of chlorosilyl group-containing compounds and / or their hydrolysates, and (2) at least one member selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyvinyl alcohol. A liquid containing an organic polymer compound is applied and dried, and heated at 350 to 650 ° C. for 5 minutes to 2 hours to form a hydrophilic metal oxide layer having an uneven surface on the photocatalytic layer. A method for producing an article having a functional surface. 29. The method for producing an article having a hydrophilic surface according to claim 28, wherein the organic polymer compound is contained in an amount of 30 to 300% by weight based on the total solid content in terms of oxide in the liquid. 30. The base material on which the photocatalyst layer is formed, wherein (1-
1) a hydrolyzable / polycondensable organometallic compound of at least one metal selected from the group consisting of silicon, aluminum, titanium, zirconium, molybdenum, vanadium and cerium, and / or a hydrolyzate thereof; -2) at least one selected from the group consisting of a chlorosilyl group-containing compound and / or a hydrolyzate thereof, and (2) a liquid containing organic polymer fine particles, followed by drying, followed by drying at 350 to 650 ° C. A method for producing an article having a hydrophilic surface which forms a layer of a hydrophilic metal oxide having an uneven surface on the photocatalyst layer by heating for from 2 minutes to 2 hours. 31. The method for producing an article having a hydrophilic surface according to claim 30, wherein the organic polymer fine particles are an acrylic resin or a styrene resin. 32. The method for producing an article having a hydrophilic surface according to claim 30, wherein the organic polymer fine particles are contained in an amount of 5 to 300% by weight based on the total solid content in terms of oxide in the liquid. 33. The hydrophilic metal oxide layer has a surface roughness having an arithmetic average roughness (Ra) of 0.5 to 100 nm and an average spacing (Sm) of the roughness of 4 to 300 nm. Item 33. The method for producing an article having a hydrophilic surface according to any one of Items 28 to 32. 34. The liquid contains the hydrolyzable / polycondensable organometallic compound or a hydrolyzate thereof and an acid, and the total of the organometallic compound and the hydrolyzate is 0 in terms of metal oxide. 0.000001-0.6% by weight, acid 0.0001-2.0 mol / L, water 0.0
The method for producing an article having a hydrophilic surface according to any one of claims 28 to 33, wherein the article is contained in an amount of 01 to 20% by weight. 35. The liquid contains the hydrolyzable / polycondensable organometallic compound or a hydrolyzate thereof, and an acid, and the total of the organometallic compound and the hydrolyzate thereof is calculated as metal oxide, 0.01 to 0.6% by weight, 0.1 to 2.0 mol / L of acid, 0.01 to 20% by weight of water
A method for producing an article having a hydrophilic surface according to any one of claims 28 to 33. 36. The hydrophilic metal oxide layer is coated with an opening reaching the photocatalyst layer.
4. The method for producing an article having a hydrophilic surface according to any one of items 3 to 5. 37. The liquid contains the hydrolyzable / polycondensable organometallic compound or a hydrolyzate thereof, and an acid, and the total of the organometallic compound and the hydrolyzate is calculated as metal oxide, 0.00001-0.3% by weight, 0.0001-1.0 mol / L acid, 0.0% water
The method for producing an article having a hydrophilic surface according to claim 36, which is contained in an amount of from 0.01 to 10% by weight. 38. The organometallic compound or its hydrolyzate is 0.001 to 0.1% by weight in terms of metal oxide, the acid is 0.01 to 0.3 mol / L, and the water content is 0.1 to 0.3 mol / L. 0
38. The method for producing an article having a hydrophilic surface according to claim 37, wherein the article is contained in an amount of 01 to 3% by weight. 39. The method for producing an article having a hydrophilic surface according to claim 28, wherein the organometallic compound is tetraethoxysilane. 40. The method for producing an article having a hydrophilic surface according to any one of claims 28 to 39, wherein the chlorosilyl group-containing compound is tetrachlorosilane.