Pane, film for applying thereto and antifogging and cleaning thereof

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a window glass that is cleaned by rainfall or water washing, and a cleaning method thereof; a window glass that has anti-fog property and a visibility in rainy weather, and an anti-fog method thereof.

【0002】

[Conventional technology]

Cleaning the windowpanes of high-rise buildings is a high-altitude work, which is both laborious and dangerous. Further, the window glass for construction of a general house cannot be easily and sufficiently cleaned with oil and fat stains due to hand stains or the like by wiping with water.

【0003】

In addition, it is often experienced that the windows are cloudy in cold or rainy weather and the outside landscape is not fully visible. In addition, when the windowpanes are exposed to rainfall or splashes and a large number of discrete water droplets adhere to the surface, the surface becomes dull, blurry, mottled, or cloudy, also loses visibility, and the outside landscape is sufficient. It disappears.

【0004】

In general, the surface of an article becomes cloudy because when the surface is placed at a temperature below the dew point of the atmosphere, the moisture in the atmosphere condenses and condenses on the surface. If the condensed water droplets are sufficiently fine and their diameter is about half the wavelength of visible light, the water droplets scatter the light, the windowpane becomes apparently opaque, and visibility is lost. If the condensation of the wet matter progresses further and the fine condensed water droplets fuse with each other to grow into larger discrete water droplets, the surface will be squeezed by the refraction of light at the interface between the water droplets and the surface and the interface between the water droplets and the air. Blurred, mottled, or cloudy. As a result, the perspective image is distorted in the window glass, and the transparency of the light beam from the headlight to the outside air is reduced. In addition, when windowpanes are exposed to rainfall or splashes and numerous discrete water droplets adhere to the surface, the surface becomes dull, blurry, mottled, or cloudy, and also loses visibility. The term "anti-fog" used here broadly means a technique for preventing such optical damage due to fogging, growth of condensed water droplets, and adhesion of water droplets.

【0005】

As is well known, a conventionally used antifogging method is to apply an antifogging composition containing a hydrophilic compound such as polyethylene glycol or a water repellent compound such as silicone to the surface. However, this type of anti-fog film is only temporary and has the disadvantage that it is easily removed by washing with water or contact and loses its effect at an early stage.

【0006】

PROBLEM TO BE SOLVED: To solve a problem of the invention.

An object of the present invention is to provide a window glass capable of achieving a high degree of visibility and a method for preventing fogging thereof. Another object of the present invention is to provide a window glass capable of maintaining a high degree of hydrophilicity for a long period of time and exhibiting antifogging property, and an antifogging method thereof. Another object of the present invention is to provide a window glass capable of maintaining a high degree of hydrophilicity almost permanently and exhibiting antifogging property, and an antifogging method thereof. Another object of the present invention is to provide a window glass that can be cleaned by rain or water washing, and a self-cleaning method and a cleaning method by the rain.

【0007】

[Means for solving problems]

The present invention is based on the discovery that in a member having a surface layer containing a photocatalyst, when the photocatalyst is photoexcited, the surface of the member becomes highly hydrophilic. This phenomenon is considered to proceed by the mechanism shown below. That is, when the photocatalyst is irradiated with light having an energy equal to or greater than the energy gap between the upper end of the valence band and the lower end of the conduction band of the photocatalyst, the electrons in the valence band of the photocatalyst are excited to generate conduction electrons and holes. , Either or both of them will probably impart polarity to the surface and collect polar components such as water and hydroxyl bands. Then, by the cooperative action of either or both of conduction electrons and holes and the polar component, the chemical bond between the surface and the pollutant chemically adsorbed on the surface is broken, and the chemically adsorbed water on the surface. Is adsorbed, and a physically adsorbed aqueous layer is formed on it. Further, once the surface of the member is highly hydrophilic, the hydrophilicity of the surface is maintained for a certain period of time even if the member is held in a dark place.

【0008】

The present invention provides an antifogging window glass having a surface layer containing substantially transparent photocatalytic oxide particles on the surface of the window glass base material. By providing a surface layer containing photocatalytic oxide particles, the surface of the surface layer becomes hydrophilic in response to photoexcitation of the photocatalyst, and condensed water and / or water droplets of adhering moisture are applied to the surface of the surface layer. It spreads uniformly and prevents clouding or swelling due to moisture condensed water and / or water droplets. Therefore, when the inner surface of the window glass becomes cloudy in cold weather or in the rain, and when the outside of the window glass receives rain or spray, a large number of scattered water droplets adhering to the surface uniformly spread on the surface of the surface layer due to the water droplets. Loss of visibility due to dullness, blurring, mottle, and cloudiness will be eliminated, and a high degree of visibility will be ensured.

【0010】

The present invention provides a self-cleaning window glass having a surface layer containing substantially transparent photocatalytic oxide particles on the surface of the window glass base material. By providing a surface layer containing photocatalytic oxide particles, the surface of the surface layer becomes hydrophilic in response to photoexcitation of the photocatalyst, and when the outer surface of the window glass is exposed to rainfall, adherent deposits and / Alternatively, the contaminants will be washed away by the raindrops.

【0011】

The present invention provides an easy-to-clean window glass having a surface layer containing substantially transparent photocatalytic oxide particles on the surface of the window glass base material. By providing a surface layer containing photocatalytic oxide particles, the surface of the surface layer becomes hydrophilic in response to photoexcitation of the photocatalyst, and the surface of the window glass can be easily washed with water, and can be rinsed with water. It can be cleaned with a simple wipe.

【0012】

In a preferred embodiment of the present invention, the surface layer is further contained with silica. By containing silica, the surface tends to exhibit a high degree of hydrophilicity close to a water wetting angle of 0 °, and the hydrophilicity retention when held in a dark place is improved. The reason seems to be related to the ability of silica to store water in its structure.

【0013】

In a preferred embodiment of the present invention, the surface layer is further contained with a solid acid. By containing the solid acid, the surface tends to exhibit a high degree of hydrophilicity close to a water wetting angle of 0 °, and the hydrophilicity retention when held in a dark place is improved. The reason is that when the surface layer contains a solid acid, the polarity of the surface is extremely large regardless of the presence or absence of light, so that water molecules, which are polar molecules, are selectively adsorbed rather than hydrophobic molecules. Easy to make. Therefore, a stable physically adsorbed aqueous layer is easily formed, and even if it is kept in a dark place, the hydrophilicity of the surface can be maintained at a high level for a considerably long period of time.

【0014】

In a preferred embodiment of the present invention, the surface layer is further contained with silicone. Due to the inclusion of silicone, at least a part of the organic groups bonded to the silicon atoms in the silicone is replaced with hydroxyl groups by the photoexcitation of the photocatalyst, and a physically adsorbed aqueous layer is formed on the hydroxyl groups, so that the surface is surfaced. It exhibits a high degree of hydrophilicity close to a water wetting angle of 0 °, and improves hydrophilicity retention when held in a dark place.

【0015】

BEST MODE FOR CARRYING OUT THE INVENTION

Next, a specific configuration of the present invention will be described. As shown in FIG. 1 or 2, a layer containing a photocatalytic (crystalline) oxide or the like is formed on the surface of the base material on the surface of the window glass in the present invention. By adopting such a surface structure, the surface of the window glass is highly hydrophilic in response to the photoexcitation of the photocatalyst. As a result, when the above surface structure is provided on the inner surface of the window glass, even if the moisture in the atmosphere condenses and adheres, it does not grow like water droplets, but becomes a uniform water film. Moisture condensate and / or water droplets prevent clouding or fogging. Further, when the above surface structure is provided on the outer surface of the window glass, even if a large number of discrete water droplets adhering to the surface are condensed and adhered when receiving rain or spray, they do not grow like water droplets. , It becomes a uniform water film, and it is prevented from becoming cloudy or fluffy by water droplets. Further, when the surface structure is provided on the outer surface of the window glass, the deposits and / or contaminants adhering to the surface of the surface layer due to rainfall are washed away by raindrops. Further, when the surface structure is provided on the surface of the window glass, the deposits and / or contaminants adhering to the surface of the surface layer can be easily washed with water, and can be easily rinsed with water or wiped with water. It will be cleaned in a degree.

【0016】

In FIG. 1, the surface layer consists only of photocatalytic oxide particles. In this case, since the photocatalyst is composed of oxides, the oxides are hydrophilic when the pollutants in the environment are not adsorbed. Therefore, the pollutants are excluded by the photoexcitation action to form an adsorbed aqueous layer. Therefore, it is easy to exhibit hydrophilicity, and a uniform water film can be formed. In FIG. 2, M represents a metallic element. Therefore, in the case of FIG. 2, the outermost surface is made of a general inorganic oxide. In this case as well, since the oxide exhibits hydrophilicity when the pollutants in the environment are not adsorbed, the pollutants are eliminated by the photoexciting action of the photocatalytic oxide mixed in the surface layer in addition to the above-mentioned inorganic oxides. By forming an adsorbed aqueous layer, a uniform aqueous film can be formed.

【0017】

Examples of the window glass base material that can be used in the present invention include window glass for buildings, window glass for vehicles, and the like.

【0018】

A photocatalyst is an excitation (photoexcitation) of electrons in the valence band when irradiated with light (excitation light) having an energy larger than the energy gap between the conduction band and the valence band of the crystal (that is, a short wavelength). ) Is generated to generate conduction electrons and holes, and the photocatalytic titanium oxide refers to crystalline titanium oxide such as anatase-type titanium oxide and rutile-type titanium oxide. Here, as the light source used for photoexcitation of the photocatalyst, a light source such as sunlight, indoor lighting, a fluorescent lamp, an incandescent lamp, a metal halide lamp, a mercury lamp, or a xenon lamp can be preferably used. In order for the surface of the substrate to be highly hydrophilic by photoexcitation of the photocatalyst, the illuminance of the excitation light is 0.001 mW / cm.²More than that is fine, but 0.01mW / cm²The above is preferable, 0.1 mW / cm²The above is more preferable.

【0019】

The film thickness of the surface layer containing photocatalytic titanium oxide is preferably 0.4 μm or less. By doing so, it is possible to prevent white turbidity due to diffused reflection of light, and the surface layer becomes substantially transparent. Further, it is more preferable that the film thickness of the surface layer containing photocatalytic titanium oxide is 0.2 μm or less. By doing so, it is possible to prevent color development of the surface layer due to light interference. Further, the thinner the surface layer, the higher the transparency. Further, if the film thickness is reduced, the wear resistance of the surface layer is improved. A wear-resistant or corrosion-resistant protective layer or another functional film that can be hydrophilized may be further provided on the surface of the surface layer.

【0020】

It is preferable that the surface layer does not have a high refractive index as compared with the base material. Preferably, the refractive index of the surface layer is 2 or less. Then, the reflection of light at the interface between the base material and the surface layer and the interface between the surface layer and air can be suppressed. To reduce the refractive index of the surface layer to 2 or less, a photocatalytic titanium oxide is added with another substance having a refractive index of 2 or less. Here, examples of other substances having a refractive index of 2 or less include calcium carbonate (refractive index 1.6), calcium hydroxide (refractive index 1.6), magnesium carbonate (refractive index 1.5), strontium carbonate (refractive index 1.5), and dolomite. (Refractive index 1.7), Calcium fluoride (Refractive index 1.4), Magnesium fluoride (Refractive index 1.4), Silica (Refractive index 1.5), Alumina (Refractive index 1.6), Silica sand (Refractive index 1.6), Montmorillonite (Refractive index 1.6) 1.5), kaolin (refractive index 1.6), sericite (refractive index 1.6), zeolite (refractive index 1.5), tin oxide (refractive index 1.9) and the like can be added to the surface layer.

【0021】

Metals such as Ag, Cu and Zn can be added to the surface layer. The surface layer to which the metal is added can kill bacteria and mold adhering to the surface even in a dark place.

【0022】

Platinum group metals such as Pt, Pd, Ru, Rh, Ir and Os can be added to the surface layer. The surface layer to which the metal is added can enhance the redox activity of the photocatalyst, and the deodorizing and purifying action and the like are improved. In addition, when a solid superacid is added in addition to the photocatalyst, the acidity of the solid superacid is improved by the addition of the platinum group metal, so that the hydrophilicity retention is also improved and the water film formation of the adhered water is further promoted. The hydrophilicity retention property is also improved when the photocatalyst is not irradiated with excitation light for a certain period of time.

【0023】

When the base material is glass containing alkaline network-modifying ions such as sodium (soda lime glass, parallel plate glass, etc.), an intermediate layer such as silica may be formed between the base material and the surface layer. By doing so, the alkali network-modifying ions are prevented from diffusing from the base material to the surface layer during firing, and the photocatalytic function is better exhibited.

【0024】

Hydrophilicity refers to the property of being easily adapted when water is dropped on the surface, and generally refers to a state in which the water wetting angle is less than 90 °. The high degree of hydrophilicity in the present invention means a property that is very familiar when water is dropped on the surface, and more specifically, a state in which the water wetting angle is about 10 ° or less. In particular, as disclosed in PCT / JP96 / 00734, the antifogging property preferably has a water wetting angle of 10 ° or less, and more preferably 5 ° or less.

【0025】

The solid acid in the present invention includes sulfuric acid-supported Al.₂O₃, Sulfuric acid supported TiO₂, Sulfuric acid-supported ZrO₂, Sulfuric acid-supported SnO₂, Sulfuric acid supported Fe₂O₃, Sulfuric acid supported SiO₂, Sulfuric acid-supported HfO₂, TiO₂/ WO₃, WO₃/ SnO₂, WO₃/ ZrO₂, WO₃/ Fe₂O₃, SiO₂ Al₂O₃, TiO₂/ SiO₂, TiO₂/ Al₂O₃, TiO₂/ ZrO₂Etc. can be preferably used.

【0026】

Next, a method of forming the surface layer will be described. First, a production method when the surface layer is composed of only a photocatalytic oxide will be described by taking the case where the photocatalyst is anatase-type titanium oxide as an example. The method in this case is roughly divided into three methods. One method is a sol coating firing method, the other method is an organic titanate method, and the other method is an electron beam deposition method. (1) Sol coating and firing method Anatase-type titanium oxide sol is applied to the surface of a substrate by a method such as a spray coating method, a dip coating method, a flow coating method, a spin coating method, or a roll coating method, and fired. (2) Organic titanate method Add a hydrolysis inhibitor (hydrolysis, ethylamine, etc.) to organic titanates such as titanium alkoxide (tetraethoxytitanium, tetramethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc.), titanium acetate, titanium chelate, etc., and alcohol (ethanol, propanol, etc.). , Butanol, etc.), and then the mixture is spray-coated, dip-coated, flow-coated, spin-coated, with partial or complete hydrolysis. Apply by method, roll coating method, etc. and dry. Drying completes the hydrolysis of organic titanate to produce titanium hydroxide, and dehydration polycondensation of titanium hydroxide forms a layer of amorphous titanium oxide on the surface of the substrate. Then, it is calcined at a temperature equal to or higher than the crystallization temperature of anatase to perform a phase transition of amorphous titanium oxide to anatase type titanium oxide. (3) Electron beam deposition method By irradiating the titanium oxide target with an electron beam, an amorphous titanium oxide layer is formed on the surface of the base material. Then, it is calcined at a temperature equal to or higher than the crystallization temperature of anatase to perform a phase transition of amorphous titanium oxide to anatase type titanium oxide.

【0027】

Next, the case where the surface layer is composed of a photocatalytic oxide and silica will be described by taking the case where the photocatalyst is anatase-type titanium oxide as an example. In this case, for example, there are the following three methods. One method is the sol coating firing method, the other method is the organic titanate method, and the other method is the tetrafunctional silane method. (1) Sol coating and firing method A mixed solution of anatase-type titanium oxide sol and silica sol is applied to the surface of the base material by a method such as a spray coating method, a dip coating method, a flow coating method, a spin coating method, or a roll coating method, and fired. (2) Organic titanate method Hydrolysis inhibitor (hydrolysis, ethylamine, etc.) and silica sol are added to organic titanates such as titanium alkoxide (tetraethoxytitanium, tetramethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc.), titanium acetate, titanium chelate, etc., and alcohol (ethanol). , Propanol, butanol, etc.), and then the mixture is spray-coated, dip-coated, flow-coated, with partial or complete hydrolysis. Apply by a method such as spin coating method or roll coating method, and dry. Drying completes the hydrolysis of organic titanate to produce titanium hydroxide, and dehydration polycondensation of titanium hydroxide forms a layer of amorphous titanium oxide on the surface of the substrate. Then, it is calcined at a temperature equal to or higher than the crystallization temperature of anatase to perform a phase transition of amorphous titanium oxide to anatase type titanium oxide. (3) 4-functional silane method A mixture of tetraalkoxysilane (tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetramethoxysilane, etc.) and anatase-type titanium oxide sol is spray-coated, dip-coated, flow-coated, spin-coated on the surface of the substrate. , The roll coating method or the like is applied, and if necessary, the silanol is hydrolyzed to form silanol, and then the silanol is subjected to dehydration-condensation polymerization by a method such as heating.

【0028】

Next, when the surface layer is composed of a photocatalytic oxide and a solid acid, the photocatalyst is anatase-type titanium oxide and the solid acid is TiO.₂/ WO₃The case of is described as an example. In this case, the method is to mix an ammonia solution of tungstic acid and anatase-type titanium oxide sol, and if necessary, spray-coat the surface of the substrate with a mixture diluted with a diluent (water, ethanol, etc.) or dip-coat. It is applied and fired by a method such as a method, a flow coating method, a spin coating method, or a roll coating method. Another method is to form an atypical titanium oxide film by electron beam deposition, hydrolysis of organic titanates such as titanium alkoxide, titanium acetate, and titanium chelate, and dehydration polycondensation, and then apply tungonic acid, and then atypical. Titanium oxide crystallizes and TiO₂/ WO₃Heat treat at the temperature at which the composite oxide is formed.

【0029】

Next, the case where the surface layer is composed of a photocatalytic oxide and silicone will be described by taking the case where the photocatalyst is anatase-type titanium oxide as an example. In this case, the method is to mix a paint consisting of uncured or partially cured silicone or a silicone precursor with anatase-type titanium oxide sol, hydrolyze the silicone precursor if necessary, and then mix. Is applied to the surface of the base material by a method such as a spray coating method, a dip coating method, a flow coating method, a spin coating method, or a roll coating method, and the hydrolyzate of the silicone precursor is subjected to dehydration polycondensation by a method such as heating. To form a surface layer composed of anatase-type titanium oxide particles and silicone. In the formed surface layer, at least a part of the organic group bonded to the silicon atom in the silicone molecule is replaced with a hydroxyl group by photoexciting the anatase-type titanium oxide by irradiation with light including ultraviolet rays, and further on the surface layer. A physically adsorbed aqueous layer is formed to exhibit a high degree of hydrophilicity. Here, the precursors of silicone include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, ethyltripropoxysilane, and phenyl. Trimethoxysilane, phenyltriethoxysilane, phenyltributoxysilane, phenyltripropoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldibutoxy Silane, diethyldipropoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldibutoxysilane, phenylmethyldipropoxysilane, γ-glycidoxypropyltrimethoxysilane, and their hydrolyzates, mixtures thereof. Can be preferably used.

【0030】

In addition, a film coated with the above coating may be attached to the surface of the base material with a transparent adhesive such as soapy water. Here, as the film base material, a plastic film such as polyethylene terephthalate, polyester, or polyethylene can be preferably used.

【0031】

Example 1. [Example]

A coating solution was prepared by mixing 0.69 g of tetraethoxysilane (Wako Pure Chemical Industries, Ltd.), 1.07 g of anatase-type titanium oxide sol (Nissan Chemical, TA-15, average particle size 10 nm), 29.88 g of ethanol, and 0.36 g of pure water. This coating liquid was applied onto a 10 cm square glass substrate by the flow coating method. By holding this glass plate at a temperature of about 150 ° C for about 20 minutes, tetraethoxysilane is subjected to hydrolysis and dehydration polycondensation, and a coating in which anatase-type titanium oxide particles are bound with amorphous silica is applied to the glass. Formed on the plate surface. The weight ratio of titanium oxide to silica in this coating was 1. After leaving this glass plate in the dark for several days, 0.5 mW / cm on the surface of the sample using an ultraviolet light source (Sankyo Electric, Black Light Blue (BLB) fluorescent lamp).²A # 1 sample was obtained by irradiating with ultraviolet rays for about 1 hour with the ultraviolet illuminance of. For comparison, a # 2 sample in which a 10 cm square glass plate was left in the dark for several days was also prepared. First, water droplets were dropped on the # 1 sample and the # 2 sample, and the state after the drops was observed and the contact angle with water was measured. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) based on the contact angle with water 30 seconds after dropping. As a result, when water droplets were dropped on the sample surface from the microsyringe of the # 1 sample, it was observed that the water droplets uniformly spread on the sample surface in the form of a water film. The contact angle with water after 30 seconds was highly hydrophilic to about 0 °. On the other hand, in the # 2 sample, when water droplets were dropped from the microsyringe onto the sample surface, the water droplets became familiar with the surface, but did not reach a uniform water film shape. The contact angle with water after 30 seconds is 30. It was. Next, the # 1 sample and the # 2 sample were blown to examine the presence or absence of fogging. As a result, the # 2 sample was cloudy, whereas the # 1 sample was not cloudy. Further, the # 1 sample was left in a dark place for 2 days thereafter to obtain a # 3 sample. Then, for the # 3 sample, the contact angle with water was similarly measured with a contact angle measuring device. As a result, when water droplets were dropped on the sample surface from the microsyringe on the # 3 sample, it was observed that the water droplets uniformly spread on the sample surface in the form of a water film, similar to the # 1 sample. The contact angle with water was maintained at about 3 °. Next, the presence or absence of cloudiness after blowing on the # 3 sample was observed. As a result, no cloudiness was observed.

【0032】

Next, oleic acid was applied to the surface of the # 3 sample, and each sample was immersed in water filled in a water tank while keeping the sample surface in a horizontal position. As a result, the oleic acid was rounded and, when lightly rubbed, came off the surface.

【0033】

Next, a slurry was prepared by suspending a powder mixture consisting of 1 part by weight of hydrophobic carbon black and 1 part by weight of hydrophilic carbon black in water at a concentration of 1.05 g / liter. 150 ml of the above slurry was allowed to flow down to a # 3 sample tilted at 45 degrees and dried for 15 minutes, then 150 ml of distilled water was allowed to flow down and dried for 15 minutes, and this cycle was repeated 25 times. The change in color difference before and after the test was measured using a color difference meter (Tokyo Denshoku). The color difference was evaluated using the ΔE * display in accordance with Japanese Industrial Standards (JIS) H0201. As a result, the change in color difference before and after the test of # 3 sample was 0.6, which was almost unchanged.

【0034】

Example 2. An amorphous titanium oxide film is adhered to the surface of a 10 cm square soda lime glass plate by an electron beam deposition method, and then fired at a temperature of 500 ° C. to crystallize the amorphous titanium oxide and anatase. Amorphous titanium oxide was produced. The film thickness of the anatase-type titanium oxide film was 100 nm. Furthermore, tungstic acid dissolved in 25% aqueous ammonia on it is converted to the weight of tungstic acid by 0.6 μg / cm.²Was applied and then fired at a temperature of 500 ° C. Next, after leaving this glass plate in the dark for several days, 0.5 mW / cm was applied to the surface of the sample using a BLB fluorescent lamp.²A # 4 sample was obtained by irradiating with ultraviolet rays for about 1 hour under the ultraviolet illuminance of. For comparison, the # 2 sample of Example 1 in which a 10 cm square glass plate was left in a dark place for several days was also prepared. First, water droplets were dropped on the # 4 sample and the # 2 sample, and the state after the drops was observed and the contact angle with water was measured. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) based on the contact angle with water 30 seconds after dropping. As a result, when water droplets were dropped on the sample surface from the microsyringe of the # 4 sample, it was observed that the water droplets uniformly spread on the sample surface in the form of a water film. The contact angle with water after 30 seconds was highly hydrophilic to about 0 °. On the other hand, in the # 2 sample, when water droplets were dropped from the microsyringe onto the sample surface, the water droplets became familiar with the surface, but did not reach a uniform water film shape. The contact angle with water after 30 seconds is 30. It was. Next, the # 4 sample and the # 2 sample were blown to examine the presence or absence of fogging. As a result, the # 2 sample was cloudy, whereas the # 4 sample was not cloudy. Further, the # 4 sample was left in a dark place for 2 days thereafter to obtain a # 5 sample. Then, for the # 5 sample, the contact angle with water was similarly measured with a contact angle measuring device. As a result, when water droplets were dropped on the sample surface from the microsyringe on the # 5 sample, it was observed that the water droplets uniformly spread on the sample surface in the form of a water film, similar to the # 4 sample. The contact angle with water was maintained at about 1 °. Next, the presence or absence of cloudiness after blowing on the # 5 sample was observed. As a result, no cloudiness was observed.

【0035】

Next, oleic acid was applied to the surface of the # 5 sample, and each sample was immersed in water filled in a water tank while keeping the sample surface in a horizontal position. As a result, the oleic acid was rounded and, when lightly rubbed, came off the surface.

【0036】

Next, a slurry was prepared by suspending a powder mixture consisting of 1 part by weight of hydrophobic carbon black and 1 part by weight of hydrophilic carbon black in water at a concentration of 1.05 g / liter. 150 ml of the above slurry was allowed to flow down to a # 5 sample tilted at 45 degrees and dried for 15 minutes, then 150 ml of distilled water was allowed to flow down and dried for 15 minutes, and this cycle was repeated 25 times. The change in color difference before and after the test was measured using a color difference meter (Tokyo Denshoku). The color difference was evaluated using the ΔE * display in accordance with Japanese Industrial Standards (JIS) H0201. As a result, the change in color difference before and after the test of # 5 sample was 0.4, which was almost unchanged.

【0037】

Example 3 First, a 10 cm square polyethylene terephthalate (PET) film is treated with corona discharge, then a primer (Shinetsu Silicone, PC-7A) is applied by the flow coating method, and a primer layer is formed by heat treatment at 120 ° C for 5 minutes. did. Next, after the primer layer was subjected to corona discharge treatment, a silicone-based hard coating agent (Shin-Etsu Silicone, KP-85) was applied by a flow coating method and heat-treated at 120 ° C. for 5 minutes to form a hard coat layer. Next, the hard coat layer was subjected to corona discharge treatment, and then a photocatalytic coating liquid (ST-K01 and ST-K03 of Ishihara Sangyo were mixed 1: 1 and then diluted with alcohol to prepare anatase-type titanium oxide and tetraethoxy. A coating solution containing a partial hydrolyzate of silane at a weight ratio of 13: 7) was applied by a flow coating method and dried at room temperature for 10 minutes to obtain a photocatalytic film. Soap water was applied to the back side of this film and attached to a 10 cm square glass substrate. Next, after leaving this glass plate in the dark for several days, 0.5 mW / cm was applied to the surface of the sample using a BLB fluorescent lamp.²A # 6 sample was obtained by irradiating with ultraviolet rays for about 1 hour under the ultraviolet illuminance of. For comparison, the # 2 sample of Example 1 in which a 10 cm square glass plate was left in a dark place for several days was also prepared. First, water droplets were dropped on the # 6 sample and the # 2 sample, and the state after the drops was observed and the contact angle with water was measured. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) based on the contact angle with water 30 seconds after dropping. As a result, it was observed that when water droplets were dropped on the sample surface of the # 6 sample from the microsyringe, the water droplets uniformly spread on the sample surface in the form of a water film. The contact angle with water after 30 seconds was highly hydrophilic to about 0 °. On the other hand, in the # 2 sample, when water droplets were dropped from the microsyringe onto the sample surface, the water droplets became familiar with the surface, but did not reach a uniform water film shape. The contact angle with water after 30 seconds is 30. It was. Next, the # 6 sample and the # 2 sample were blown to examine the presence or absence of fogging. As a result, the # 2 sample was cloudy, whereas the # 4 sample was not cloudy. Further, the # 6 sample was left in a dark place for 2 days thereafter to obtain a # 7 sample. Then, for the # 7 sample, the contact angle with water was similarly measured with a contact angle measuring device. As a result, when water droplets were dropped on the sample surface from the microsyringe on the # 7 sample, it was observed that the water droplets uniformly spread on the sample surface like a water film as in the # 6 sample. The contact angle with water was maintained at about 1 °. Next, the presence or absence of cloudiness after blowing on the # 7 sample was observed. As a result, no cloudiness was observed.

【0038】

Next, oleic acid was applied to the surface of the # 7 sample, and each sample was immersed in water filled in a water tank while keeping the sample surface in a horizontal position. As a result, the oleic acid was rounded and, when lightly rubbed, came off the surface.

【0039】

Next, a slurry was prepared by suspending a powder mixture consisting of 1 part by weight of hydrophobic carbon black and 1 part by weight of hydrophilic carbon black in water at a concentration of 1.05 g / liter. 150 ml of the above slurry was allowed to flow down to a # 7 sample tilted at 45 degrees and dried for 15 minutes, then 150 ml of distilled water was allowed to flow down and dried for 15 minutes, and this cycle was repeated 25 times. The change in color difference before and after the test was measured using a color difference meter (Tokyo Denshoku). The color difference was evaluated using the ΔE * display in accordance with Japanese Industrial Standards (JIS) H0201. As a result, the color difference change of the # 7 sample before and after the test was 0.8, which was almost unchanged.

【0040】

[Effect of the invention]

In the present invention, by providing the surface of the window glass with a surface layer containing substantially transparent photocatalytic oxide particles, the surface of the surface layer becomes hydrophilic in response to photoexcitation of the photocatalyst. As a result, the adhered wet condensed water and / or water droplets spread uniformly on the surface of the surface layer, and the wet condensed water and / or water droplets prevent fogging or swelling. In addition, the surface of the surface layer is self-cleaned by rainfall. Further, the surface of the surface layer will be cleaned only by rinsing with water or a simple wiping with water.

[Simple explanation of drawings]

[Figure 1]

The figure which shows the surface structure of the window glass which concerns on this invention.

[Figure 2]

The figure which shows the other surface structure of the window glass which concerns on this invention.