JPH09230118A - Anti-fogging mirror for vehicle, automobile having the same, anti-fogging film for mirror for vehicle and anti-fogging method of mirror for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the condensed water of moisture and/or water drops adhered to the surface of a mirror for vehicles to spread uniformly on the surface layer and to assure a visual field characteristic by providing the surface of this mirror with the surface layer contg. transparent photocatalytic titanium oxide particles. SOLUTION: The layer contg. photocatalysts is formed on the surface of a base material. The surface of the mirror for vehicles is made highly hydrophilic according to the photoexcitation of the photocatalysts. As a result, even if the moisture of the atmosphere condenses and adheres to the mirror surface, the condensed moisture does not grow to the form of water drops and turns to the form of a uniform water film. The fogging by the condensed water of moisture and/or the water drops is thus prevented. The photocatalysts are an oxide and this oxide exhibits hydrophilicity in the state that the contaminants in the environment are not adsorbed and, therefore, these contaminants are expelled by the photoexcitation effect and the adsorbed water layer is formed, by which the hydrophilicity is easily rendered and the uniform water film is formed. Fig. shows a metal element M and the extreme surface consists of a general inorg. oxide. Then, the contaminants are expelled by the effect of the photocatalyst titanium oxide incorporated into the surface layer exclusive of the inorg. oxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle mirror that can be used as a fender mirror for automobiles, a rear view mirror for motorcycles, and the like, and a method for defrosting a vehicle mirror.

[0002]

2. Description of the Related Art Vehicle mirrors, such as automobile fender mirrors and motorcycle rear view mirrors, are subject to rainfall and splashes, and a large number of discrete water droplets adhere to the surface, and those surfaces are wavy, blurred, and mottled. It is often experienced that it becomes dull or cloudy and loses visibility.
If the condensed water droplets are sufficiently fine and their diameter is about ½ of the wavelength of visible light, the water droplets scatter light, the vehicle mirror becomes opaque in appearance, and visibility is lost. If moisture condensation proceeds further and fine condensed water droplets coalesce with each other to grow into larger discrete water droplets, the surface will be shaded due to refraction of light at the water droplet-surface interface and the water-air interface. Blurred, mottled, or cloudy,
Visibility is lost. As used herein, the term "anti-fog" broadly refers to a technique for preventing optical hindrance due to such fogging, growth of condensed water droplets, and adhesion of water droplets.

As is well known, the 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 kind of anti-fog coating is only temporary, and has the drawback that it is easily removed by washing or contact and loses its effect early.

[0004]

A vehicle fender mirror,
Vehicle rearview mirrors such as motorcycle rearview mirrors are subject to rainfall and splashes, and a large number of discrete water droplets are attached to the surface, and those surfaces are shaded, blurred, mottled, or clouded, and visibility is lost. Doing so will interfere with the safe driving of cars and motorcycles. Therefore, it is an object of the present invention to provide a vehicle mirror capable of realizing a high degree of visibility and an anti-fog method therefor. Another object of the present invention is to provide a vehicle mirror capable of maintaining a high degree of hydrophilicity for a long period of time and exhibiting an antifogging property, and a method for antifogging the same. Another object of the present invention is to provide a vehicle mirror capable of maintaining a high degree of hydrophilicity almost permanently and exhibiting an antifogging property, and a method for preventing the same.

[0005]

SUMMARY OF THE INVENTION The present invention is based on the discovery that, in a member having a surface layer containing a photocatalyst formed thereon, when the photocatalyst is photoexcited, the surface of the member is highly hydrophilized. This phenomenon is considered to proceed by the following mechanism. That is, when the photocatalyst is irradiated with light having an energy larger than the energy gap between the valence band upper end and the conduction band lower end of the photocatalyst, the electrons in the valence band of the photocatalyst are excited to generate conduction electrons and holes. The action of either or both of them probably imparts polarity to the surface and collects polar components such as water and hydroxyl groups. Then, one or both of conduction electrons and holes and the above-mentioned polar component cooperate with each other to cut off a chemical bond between the surface and the contaminant chemically adsorbed on the surface, and to cause a chemical adsorbed water on the surface. Is adsorbed, and a physically adsorbed water layer is formed thereon. Further, once the surface of the member is highly hydrophilized, the hydrophilicity of the surface is maintained for a certain period even if the member is kept in a dark place.

In the present invention, on the surface of the vehicle mirror base material,
Provided is an anti-fog vehicle mirror having a surface layer containing a substantially transparent photocatalyst. By providing a surface layer containing a photocatalyst, in response to photoexcitation of the photocatalyst, the surface of the surface layer exhibits hydrophilicity, the condensed water and / or water droplets of the attached moisture spread evenly on the surface of the layer, Moisture condensate and / or water drops will prevent fogging or overhang.

In a preferred embodiment of the present invention, the surface layer further contains silica. By containing silica, the surface is likely to exhibit a high degree of hydrophilicity near 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.

In a preferred embodiment of the present invention, the surface layer further contains a solid acid. When the solid acid is contained, the surface is likely to exhibit a high degree of hydrophilicity near a water wetting angle of 0 °, and the hydrophilicity retention when kept in a dark place is improved. The reason is that when a solid acid is contained in the surface layer, the polarity of the surface is large regardless of the presence or absence of light, so it is easier to selectively adsorb water molecules that are polar molecules than hydrophobic molecules. . Therefore, a stable physical adsorption water layer is easily formed, and even if it is kept in a dark place,
Surface hydrophilicity can be maintained at a high level for a fairly long time.

In a preferred embodiment of the present invention, the surface layer further contains silicone.
By containing silicone, by photoexcitation of the photocatalyst, at least a part of the organic group bonded to the silicon atom in the silicone is replaced with a hydroxyl group, and a physically adsorbed water layer is formed on the organic group, so that the surface is It exhibits a high degree of hydrophilicity close to a water wetting angle of 0 °, and improves the hydrophilicity maintaining ability when kept in a dark place.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a specific structure of the present invention will be described. As shown in FIG. 1 or FIG. 2, a layer containing a photocatalyst is formed on the surface of the base material on the surface of the anti-fog vehicle mirror in the present invention. By taking such a surface structure, the surface of the vehicle mirror is highly hydrophilized in response to photoexcitation of the photocatalyst. As a result, even if the moisture in the atmosphere is condensed and adheres, it does not grow in the form of water droplets, and a uniform water film is formed, which prevents the moisture condensed water and / or water droplets from clouding or clinging. It

In FIG. 1, when the surface layer is composed of only the photocatalyst, the photocatalyst is preferably an oxide.
By doing so, the oxide shows hydrophilicity in the state where the pollutants in the environment are not adsorbed, so that the pollutants are rejected by the photoexcitation action and the adsorbed water layer is formed, so that the oxides easily exhibit hydrophilicity. A uniform water film can be formed. In FIG. 2, M represents a metal element. Therefore, in the case of FIG. 2, the outermost surface is made of a general inorganic oxide. Again,
Since the oxide is hydrophilic when the pollutants in the environment are not adsorbed, the photocatalytic titanium oxide mixed into the surface layer other than the inorganic oxide removes the contaminants by the photoexciting action, and the adsorbed water layer Is formed, a uniform water film can be formed.

The vehicle mirror base material in the present invention includes a mirror made of a glass base material having a reflective coating on the back surface, a mirror made of a transparent plastic base material having a reflective coating on the back surface,
A reflective coat is provided on the surface of a substrate made of plastic, glass, metal, etc., and a transparent hard coat is provided on a mirror with a transparent hard coat on it, and a transparent plastic substrate with a reflective coat on the back. A mirror having a transparent surface, such as a mirror, can be preferably used.

A photocatalyst is a photocatalyst of electrons in the valence band when irradiated with light (excitation light) having an energy (that is, a short wavelength) larger than the energy gap between the conduction band and the valence band of the crystal. A substance that is excited (photoexcited) to generate conduction electrons and holes. For example, anatase-type titanium oxide, rutile-type titanium oxide, tin oxide, zinc oxide, dibismuth trioxide, tungsten trioxide, and oxide oxide. Diiron, strontium titanate and the like can be preferably used. Here, as the light source used for photoexcitation of the photocatalyst, sunlight, street lights, lighting in tunnels, night lights, and other light sources in the running environment may be used, and as auxiliary equipment or portable equipment,
A light source that can emit excitation light may be used. As the light source used in that case, for example, a fluorescent lamp, an incandescent lamp, a metal halide lamp, a mercury lamp, a xenon lamp, a germicidal lamp and the like can be suitably used. In order to make the surface of the base material highly hydrophilic by photoexcitation of the photocatalyst, the illuminance of the excitation light is 0.
001 mW / cm ² or more is sufficient, but 0.01 mW / cm ²
cm ² or more is preferable, and 0.1 mW / cm ² or more is more preferable.

The film thickness of the surface layer containing the photocatalyst is 0.4.
It is preferable that the thickness is less than or equal to μm. Then, white turbidity due to irregular reflection of light can be prevented, and the surface layer becomes substantially transparent. More preferably, the thickness of the surface layer containing the photocatalyst is 0.2 μm or less. that way,
Coloring of the surface layer due to light interference can be prevented.
Also, the thinner the surface layer, the better its transparency. Further, when the film thickness is reduced, the wear resistance of the surface layer is improved. The surface of the surface layer may be further provided with a wear-resistant or corrosion-resistant protective layer capable of being made hydrophilic and other functional films.

The surface layer preferably has a refractive index that is not so high as that of the substrate. Preferably, the refractive index of the surface layer is 2 or less. Then, light reflection at the interface between the substrate and the surface layer and the interface between the surface layer and air can be suppressed. In order to reduce the refractive index of the surface layer to 2 or less, a substance having a refractive index of 2 or less is used for the photocatalyst, or if the photocatalyst has a refractive index of 2 or more, another substance having a refractive index of 2 or less is used for the surface layer. To be added. As a photocatalyst having a refractive index of 2 or less, tin oxide (refractive index: 1.9) or the like can be used. 2
Photocatalysts having the above refractive index include anatase type titanium oxide (refractive index 2.5) and rutile type titanium oxide (refractive index 2.7). In this case, other substances having a refractive index of 2 or less, For example, calcium carbonate (refractive index 1.6), calcium hydroxide (refractive index 1.6), magnesium carbonate (refractive index 1.5), strontium carbonate (refractive index 1.5), 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.
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 may be added to the surface layer.

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 fungi attached to the surface even in a dark place.

On the surface layer, Pt, Pd, Ru, R
A platinum group metal such as h, Ir, Os can be added. The surface layer to which the metal is added can enhance the oxidation-reduction activity of the photocatalyst and improve the deodorizing and purifying action and the like. In addition, when a solid acid is added in addition to the photocatalyst, the acidity of the solid acid is improved by the addition of a platinum group metal, so that the hydrophilicity is also improved, and the formation of a water film on the attached water is further promoted. The hydrophilicity when the excitation light is not irradiated to the photocatalyst for a long period of time is also improved. Mo can be added to the surface layer. When a solid acid is added in addition to the photocatalyst, the addition of Mo increases the acidity of the solid acid, so that the hydrophilicity is also improved, and the formation of a water film on the attached water is further promoted. The hydrophilicity when light is not irradiated is also improved.

When the substrate is a glass containing alkali network modifying ions such as sodium (soda lime glass, parallel plate glass, etc.), an intermediate layer such as silica may be formed between the substrate and the surface layer. Good. Then, the diffusion of the alkali network modifying ions from the base material to the surface layer during the firing is prevented, and the photocatalytic function is more effectively exhibited.

The term "hydrophilic" refers to the property of easily fitting into the surface when water is dropped, and generally means a state where the water wetting angle is less than 90 °. The term “high hydrophilicity” in the present invention refers to a property that is highly compatible when water is dropped on the surface, and more specifically, a state where the water wetting angle is about 10 ° or less. In particular, as disclosed in PCT / JP96 / 00734, the water wetting angle is preferably 10 ° or less, more preferably 5 ° or less, as disclosed in PCT / JP96 / 00734.

The solid acid used in the present invention includes Al carrying sulfuric acid.
₂ O ₃ , sulfuric acid supported TiO ₂ , sulfuric acid supported ZrO ₂ , sulfuric acid supported SnO ₂ , sulfuric acid supported Fe ₂ O ₃ , sulfuric acid supported SiO ₂ ,
Sulfuric acid supporting HfO ₂ , TiO ₂ / WO ₃ , WO ₃ / SnO
₂ , WO ₃ / ZrO ₂ , WO ₃ / Fe ₂ O ₃ , SiO _{2
· Al 2 O 3, TiO 2} / SiO 2, TiO 2 / Al 2
O ₃ , TiO ₂ / ZrO _{2 and the} like can be preferably used.

Next, a method for forming the surface layer will be described. First, the production method in the case where the surface layer is composed of only the photocatalyst will be described by taking the case where the photocatalyst is anatase type titanium oxide as an example. In this case, there are roughly three methods. One method is a sol coating and firing method, the other method is an organic titanate method, and the other method is an electron beam evaporation 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 spray coating, dip coating, flow coating, spin coating, or roll coating, and then fired. (2) Organic titanate method Titanium alkoxide (tetraethoxy titanium, tetramethoxy titanium, tetrapropoxy titanium, tetrabutoxy titanium, etc.), titanium acetate, titanium chelate, etc. are added with a hydrolysis inhibitor (hydrochloric acid, ethylamine, etc.). , After diluting with a non-aqueous solvent such as alcohol (ethanol, propanol, butanol, etc.), while partially or completely proceeding the hydrolysis, the mixture is spray-coated, dip-coated, Apply by methods such as flow coating method, spin coating method, roll coating method,
dry. By drying, the hydrolysis of the organic titanate is completed to produce titanium hydroxide, and a layer of amorphous titanium oxide is formed on the surface of the base material by dehydration-condensation polymerization of the titanium hydroxide. Thereafter, the amorphous titanium oxide is calcined at a temperature equal to or higher than the crystallization temperature of anatase to cause a phase transition from the amorphous titanium oxide to the anatase titanium oxide. (3) Electron beam evaporation method An amorphous titanium oxide layer is formed on the surface of a substrate by irradiating a titanium oxide target with an electron beam. After that, firing at a temperature higher than the crystallization temperature of anatase,
Phase transition of amorphous titanium oxide to anatase titanium oxide.

Next, the case where the surface layer is composed of a photocatalyst 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 is the organic titanate method, the other is 4
This is a functional silane method. (1) Sol coating and baking method A mixture of anatase-type titanium oxide sol and silica sol is applied to the substrate surface by a method such as a spray coating method, a dip coating method, a flow coating method, a spin coating method, and a roll coating method, and then fired. I do. (2) Organic titanate method Titanium alkoxides (tetraethoxytitanium, tetramethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc.), titanium acetate, titanium chelate, and other organic titanates are added with a hydrolysis inhibitor (hydrochloric acid, ethylamine, etc.) and silica sol. Add alcohol (ethanol,
After diluting with a non-aqueous solvent such as propanol, butanol, etc., and then allowing the hydrolysis to proceed partially or completely, the mixture is spray-coated, dip-coated, flow-coated,
It is applied by a method such as spin coating or roll coating and dried. By drying, the hydrolysis of the organic titanate is completed to produce titanium hydroxide, and a layer of amorphous titanium oxide is formed on the surface of the base material by dehydration-condensation polymerization of the titanium hydroxide. Thereafter, the amorphous titanium oxide is calcined at a temperature equal to or higher than the crystallization temperature of anatase to cause a phase transition from the amorphous titanium oxide to the anatase titanium oxide. (3) Tetrafunctional silane method A mixture of tetraalkoxysilane (tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetramethoxysilane, etc.) and anatase type titanium oxide sol is spray-coated or dip-coated on the surface of a substrate. , A flow coating method, a spin coating method, a roll coating method, or the like, and if necessary, hydrolyzing to form silanol, and then silanol is subjected to dehydration condensation polymerization by a method such as heating.

Next, the case where the surface layer is composed of a photocatalyst and a solid acid will be described by taking as an example the case where the photocatalyst is anatase type titanium oxide and the solid acid is TiO ₂ / WO ₃ . One method in this case is a method in which an ammonia solution of tungstic acid and an anatase type titanium oxide sol are mixed, and if necessary, a mixture diluted with a diluent (water, ethanol, etc.) is spray-coated on the surface of the base material, Dip coating method, flow coating method, spin coating method,
It is applied by a method such as a roll coating method and baked. Other methods include electron beam evaporation and hydrolysis and dehydration polycondensation of organic titanates such as titanium alkoxide, titanium acetate, and titanium chelate to form an amorphous titanium oxide film, and then tungstic acid is applied to the amorphous titanium oxide. Is crystallized and a heat treatment is performed at a temperature at which a TiO ₂ / WO ₃ composite oxide is formed.

Next, the case where the surface layer is composed of a photocatalyst and silicone will be described by taking the case where the photocatalyst is anatase type titanium oxide as an example. The method in this case is to mix a coating composed of uncured or partially cured silicone or a precursor of silicone and anatase type titanium oxide sol, and hydrolyze the precursor of silicone as needed, and then mix the mixture. Spray coating method on the surface of the substrate,
It is applied by a method such as a dip coating method, a flow coating method, a spin coating method, a roll coating method, etc., and a hydrolyzate of a silicone precursor is subjected to dehydration polycondensation by a method such as heating to obtain anatase type titanium oxide particles. A surface layer made of silicone is formed. The formed surface layer, by photoexcitation of anatase type titanium oxide by irradiation with light including ultraviolet rays, at least a part of the organic group bonded to the silicon atom in the silicone molecule is substituted with a hydroxyl group, and further on it. A physically adsorbed water layer is formed,
It exhibits a high degree of hydrophilicity. Here, the precursor of silicone includes methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, ethyltripropoxysilane, and phenyl. Trimethoxysilane, phenyltriethoxysilane, phenyltributoxysilane,
Phenyltripropoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldibutoxysilane, diethyldipropoxysilane, phenylmethyldimethoxysilane, phenylmethyl Diethoxysilane, phenylmethyldibutoxysilane, phenylmethyldipropoxysilane, γ-glycidoxypropyltrimethoxysilane, a hydrolyzate thereof, and a mixture thereof can be suitably used.

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

[0026]

【Example】

Embodiment 1 FIG. (+ Amorphous silica) 0.69 g of tetraethoxysilane (Wako Pure Chemical Industries), 1.07 g of anatase type titanium oxide sol (TA-15, average particle size 10 nm), and 29.88 g of ethanol,
0.36 g of pure water was mixed to prepare a coating liquid.
This coating solution was applied by flow coating to 1
It was applied onto a 0 cm square glass mirror substrate (a substrate having a reflection coating layer and a resin layer formed on the back surface of a plate glass). By holding this glass mirror 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 by amorphous silica is applied to the glass mirror plate. Formed on the surface. The weight ratio of titanium oxide and silica in this coating was 1. After leaving this glass end plate in the dark for several days, it is then exposed to an ultraviolet light source (Sankyo Denki, Black Light Blue (B
LB) fluorescent lamp) on the surface of the sample 0.5mW / cm
^The sample was irradiated with ultraviolet rays at an ultraviolet illuminance of ² for about 1 hour to obtain a # 1 sample. For comparison, a # 2 sample in which a 10 cm square glass end plate was left in the dark for several days was also prepared. First, # 1 sample and #
Drops of water were dropped on the two samples, and the state after the drop 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 a water drop was dropped from the micro syringe onto the sample surface, it was observed that the water droplet spread uniformly on the sample surface in a water film shape. Further, the contact angle with water after 30 seconds was highly hydrophilized to about 0 °. On the other hand, in the case of the # 2 sample, when a water drop was dropped on the sample surface from the microsyringe, the water droplet adapted to the surface but did not reach a uniform water film state. The contact angle with water after 30 seconds was 30 °. Next, the # 1 sample and the # 2 sample were blown to examine whether or not clouding occurred. As a result, fogging occurred in the # 2 sample, but no fogging occurred in the # 1 sample. Further, the # 1 sample was left in a dark place for two days thereafter, to obtain a # 3 sample. Then, for the # 3 sample, the contact angle with water was similarly measured by a contact angle measuring device. As a result, when a water droplet is dropped from the microsyringe on the sample surface of # 3 sample,
Similar to the # 1 sample, it was observed that water droplets spread uniformly on the sample surface in the form of a water film. The contact angle with water was maintained at about 3 °. Next, the presence or absence of fogging after spraying was observed for the # 3 sample. As a result, no fogging was observed.

Embodiment 2 FIG. (+ TiO ₂ / WO ₃ ) An amorphous titanium oxide film is deposited on the surface of a 10 cm square soda lime glass plate by an electron beam evaporation method, and then 50
By firing at a temperature of 0 ° C., the amorphous titanium oxide was crystallized to produce anatase type titanium oxide. The film thickness of the anatase type titanium oxide film was 100 nm. Furthermore, tungstic acid dissolved in 25% aqueous ammonia was added thereto and converted to a tungstic acid weight of 0.1%.
After applying 6 μg / cm ² , it was baked at a temperature of 500 ° C.
Next, a mirror was manufactured by forming a reflective coating of aluminum on the back surface of this glass plate by vacuum vapor deposition. After leaving this glass end plate in the dark for several days, the surface of the sample was irradiated with ultraviolet rays at an ultraviolet illuminance of 0.5 mW / cm ² for about 1 hour using a BLB fluorescent lamp to obtain a # 4 sample. For comparison, the # 2 sample used in Example 1 in which a 10 cm square glass end plate was left in the dark for several days was also prepared. First, a water drop was dropped on the # 4 sample and the # 2 sample, and the state after the drop was observed and the contact angle with water was measured. As a result, it was observed that when water droplets were dropped from the microsyringe on the sample surface of the # 4 sample, the water droplets spread uniformly on the sample surface in the form of a water film. Further, the contact angle with water after 30 seconds was highly hydrophilized to about 0 °. On the other hand, in the case of the # 2 sample, when a water drop was dropped on the sample surface from the microsyringe, the water droplet adapted to the surface but did not reach a uniform water film state. The contact angle with water after 30 seconds was 30 °. Next, the # 4 sample and the # 2 sample were blown to examine whether or not fogging occurred. As a result, the # 2 sample generated haze, whereas the # 4 sample did not. Further, the # 4 sample was left in a dark place for two days thereafter to obtain a # 5 sample. Then, for the # 5 sample, the contact angle with water was similarly measured by a contact angle measuring device. As a result, when a water droplet was dropped on the sample surface from the microsyringe on the # 5 sample, it was observed that the water droplet spread uniformly over the sample surface in the form of a water film, similarly to the # 4 sample. The contact angle with water was maintained at about 1 °.
Next, with respect to the # 5 sample, it was observed whether or not clouding occurred after the breathing. As a result, no fogging was observed.

Embodiment 3 FIG. (+ TiO2 / amorphous silica,
Film sticking) First, 10 cm square polyethylene terephthalate (PE
T) After corona discharge treatment of the film, a primer (Shin-Etsu Chemical, PC-7A) is applied by a flow coating method,
A primer layer was formed by heat treatment at 120 ° C. for 5 minutes. Next, after the primer layer was subjected to corona discharge treatment, a silicone hard coating solution was applied by a flow coating method and heat-treated at 120 ° C. for 10 minutes to form a hard coating layer. Next, after the corona discharge treatment of the hard coating layer, a photocatalyst coating liquid (a mixed liquid of 13 parts by weight of titanium oxide and 7 parts by weight of tetraethoxysilane dispersed in a mixed solvent of water and alcohol) was applied by a flow coating method. Then, it was 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 the surface of a 10 cm square mirror substrate. After leaving this glass end plate in the dark for several days, the surface of the sample was irradiated with ultraviolet rays at an ultraviolet illuminance of 0.5 mW / cm ² for about 1 hour using a BLB fluorescent lamp to obtain a # 6 sample. For comparison, the # 2 sample used in Example 1 in which a 10 cm square glass end plate was left in the dark for several days was also prepared. First, water drops were dropped on the # 6 sample and the # 2 sample, and the state after the drop 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 the # 6 sample was dropped from the microsyringe onto the sample surface, it was observed that the water droplet spreads uniformly on the sample surface in the form of a water film. Further, the contact angle with water after 30 seconds was highly hydrophilized to about 0 °. On the other hand, in the case of the # 2 sample, when a water drop was dropped on the sample surface from the microsyringe, the water droplet adapted to the surface but did not reach a uniform water film state. The contact angle with water after 30 seconds was 30 °. Next, the # 6 sample and the # 2 sample were blown to examine whether or not fogging occurred. As a result, the # 2 sample generated haze, whereas the # 6 sample did not. Further, the # 6 sample was left in a dark place for 2 days to obtain a # 7 sample. Then, for the # 7 sample, the contact angle with water was similarly measured by a contact angle measuring device. As a result, when water droplets were dropped on the sample surface from the # 7 sample from the microsyringe,
Similar to the # 6 sample, it was observed that water droplets spread uniformly on the sample surface in the form of a water film. The contact angle with water was maintained at about 3 °. Next, with respect to the # 7 sample, it was observed whether or not clouding had occurred after breathing. As a result, no fogging was observed.

[0029]

According to the present invention, the surface of the mirror layer for vehicles is provided with a surface layer containing substantially transparent photocatalytic titanium oxide particles, whereby the surface of the surface layer becomes hydrophilic in response to photoexcitation of the photocatalyst. Moisture condensed condensed water and / or water droplets that have adhered and spread evenly on the surface of the layer, and even if it is rained or splashed, it is prevented that the moisture condensed water and / or water droplets cause clouding or overhang. And visibility will be secured.

[Brief description of drawings]

FIG. 1 is a diagram showing a surface structure of a vehicle mirror according to the present invention.

FIG. 2 is a diagram showing another surface structure of the vehicle mirror according to the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Kanno 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka

Claims (21)

[Claims] 1. A vehicle mirror substrate surface is provided with a surface layer containing substantially transparent photocatalyst particles, and in response to photoexcitation of the photocatalyst, the surface of the layer exhibits hydrophilicity and is thus attached. An anti-fogging vehicle mirror, in which condensed water and / or water droplets of moisture are evenly spread on the surface of the layer to prevent the condensed water and / or water droplets from being fogged or covered. 2. The anti-fogging vehicle mirror according to claim 1, wherein the surface layer further contains silica. 3. The anti-fog vehicle mirror according to claim 1, wherein the surface layer further contains a solid acid. 4. The anti-fog vehicle mirror according to claim 1, wherein the surface layer further contains silicone. 5. The surface of the surface layer exhibits hydrophilicity of 10 ° or less in terms of contact angle with water in response to photoexcitation of the photocatalyst. Anti-fog vehicle mirror. 6. The anti-fog vehicle mirror according to claim 1, wherein the surface layer has a film thickness of 0.4 μm or less. 7. The anti-fogging vehicle mirror according to claim 1, wherein the surface layer has a thickness of 0.2 μm or less. 8. A hydrophilic protective layer is further provided on the surface of the surface layer.
The anti-fog vehicle mirror according to item 5. 9. The anti-fog vehicle mirror according to claim 1, wherein the surface layer has a refractive index of 2 or less. 10. An automobile provided with the anti-fog vehicle mirror according to any one of claims 1 to 9. 11. A motorcycle comprising the anti-fog vehicle mirror according to claim 1. 12. The surface of a film substrate is provided with a surface layer containing substantially transparent photocatalyst particles, and when adhered to a vehicle mirror surface, the vehicle mirror surface responds to photoexcitation of the photocatalyst. It exhibits hydrophilicity, whereby the condensed water and / or water droplets of the adhered moisture are spread evenly on the surface of the layer, so that the condensed water of moisture and / or the water droplets can be prevented from clouding or overhanging. Anti-fog film for vehicle mirrors. 13. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer further contains silica. 14. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer further contains a solid acid. 15. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer further contains silicone. 16. The surface of the surface layer exhibits hydrophilicity of 10 ° or less in terms of contact angle with water according to photoexcitation of the photocatalyst. Anti-fog film for vehicle mirrors. 17. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer has a thickness of 0.4 μm or less. 18. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer has a thickness of 0.2 μm or less. 19. The protective layer which can be further hydrophilized is provided on the surface of the surface layer.
The antifogging film for a vehicle mirror according to any one of 2 to 16. 20. The anti-fogging film for a vehicle mirror according to claim 12, wherein the surface layer has a refractive index of 2 or less. 21. A step of preparing a vehicle mirror according to any one of claims 1 to 9, wherein the surface of the layer is rendered hydrophilic by photoexciting a photocatalyst contained in a surface layer of the vehicle mirror. A method for defrosting a vehicle mirror, comprising the step of allowing condensed water and / or water droplets of the above-mentioned moisture to spread uniformly on the surface of the layer.