JP2000321411A - Anti-fogging mirror for bathroom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To repeatedly reproduce a highly hydrophilic surface with a simple cleaning means and to maintain excellent anti-fogging and antifouling properties over a long period in the anti-fogging mirror for a bathroom by imparting specified values to the average height, the average width and the center line average surface roughness respectively in a layer surface composed of a hydrophilic inorganic oxide. SOLUTION: A layer composed of a hydrophilic inorganic oxide is formed on a substrate surface. A projecting and recessing structure with average height and average width of respectively 0.4-200 nm and 0.1-50 nm center line average surface roughness Ra at an arbitrary position of the substrate surface measured with an atomic force microscope for the layer surface is formed. The method for forming projecting and recessing parts on the substrate surface is optionally selected from well-known methods. A method for forming a film with fine projecting and recessing parts on the substrate surface such as a sol coating method, a plating method, a CVD method, a sputtering method or a vacuum deposition method, a method for directly forming projecting and recessing parts on the substrate such as a sandblast method or an etching method and a method for forming fine projecting and recessing parts on a forming mold and transferring them to the substrate are mentioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fogging property and a drip-proof property which can be suitably used mainly in a bathroom or a shower room under an environment where a large amount of dirt is added to the soil and where a large amount of water vapor or water is constantly applied. The present invention relates to a hydrophilic antifogging mirror for bathrooms having excellent antifouling properties and self-cleaning properties.

[0002]

2. Description of the Related Art As a method for preventing fogging and dirt on a bathroom mirror, it has been conventionally performed to impart hydrophilicity to the mirror surface. Known methods for imparting hydrophilicity include a method of applying a surfactant to a mirror surface and a method of applying a hydrophilic substance such as a hydrophilic monomer or polymer. According to the method of applying a surfactant, water droplets attached to the surface by the surfactant are formed into a water film, so that the hydrophilic monomer
According to the method of applying a polymer, etc., by absorbing water adhering to the mirror surface, adhesion and formation of water droplets are prevented,
It becomes possible to prevent fogging and dirt on the member surface. Japanese Patent Application Laid-Open No. Hei 7-236553 also discloses that once water is applied to a mirror surface made of ground glass in which innumerable scratches are formed to form unevenness parallel to the surface, water that has entered the concave portion is used. Is transparent when it is flat, and fogging is prevented by its water film.

[0003]

The surfactant / hydrophilic substance easily flows down due to moisture, and there is a problem in the sustainability of the effect especially in an environment where water is frequently applied such as a bathroom. In addition, the surface of a hydrophilic monomer / polymer becomes soft and easily damaged when water is absorbed. In particular, when used in an environment having a high vapor pressure in a use environment such as a bathroom, the amount of water absorption increases, and the tendency becomes very remarkable. Further, there is a disadvantage that both the surfactant and the hydrophilic monomer / polymer easily adsorb dirt and the like in the air. Above all, bathrooms are not only stains caused by metal ions in tap water, soap scum and sebum, but also detergents used during hair washing and washing, especially silicone oil which is also a moisturizing component in rinsing, Very many contaminants, such as cationic surfactants, that attach to the mirror surface and change the mirror surface to a property that repels water easily.
Furthermore, they are scattered directly at the time of hair washing / washing, are scattered indirectly by a shower, and are in a state of being easily attached. In addition, since the bathroom is rich in moisture and organic matter, microorganisms are easy to propagate especially in a portion having irregularities, and the microorganisms may propagate on a mirror surface having irregularities and inhibit hydrophilicity. As described above, the bathroom environment is in an environment where various kinds of dirt is present and easily adheres, the pollution load is large, and the environment is frequently exposed to water. Stain can be exhibited only while the initial mirror can maintain a clean state, and it has been almost impossible to maintain the antifogging property and antifouling property for a long time.

According to the present invention, a highly hydrophilic surface is repeatedly reproduced by a simple cleaning method such as spraying water with a shower or the like, which has been difficult to realize for the above-described reasons, and good anti-fog and anti-fog properties can be obtained over a long period of time. An object of the present invention is to provide a hydrophilic anti-fog mirror for bathrooms that can maintain soiling.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a layer made of a hydrophilic inorganic oxide is formed on the surface of a substrate, and the surface of the layer is measured with an atomic force microscope. The height and width of the irregularities at an arbitrary position on the substrate surface are 0.4 nm or more and 200 nm or less, and the center line average surface roughness R
a is formed to have an uneven structure having a thickness of 0.1 nm or more and 50 nm or less. More preferably, the average height of the unevenness is 0.8 nm or more and 40 nm or less, and the average width of the unevenness is 9 nm or more.
The center line average surface roughness Ra is set to 0.1 nm or more and 10 nm or less. By forming a layer made of a hydrophilic inorganic oxide on the surface of the base material and forming such a concavo-convex structure on the surface of the base material, the following functions can be exerted without deteriorating the texture of the base material. (1) Since the hydrophilic surface has a fractal structure (a structure having a fractal dimension of 2.01 to 2.99), the hydrophilic surface exhibits high hydrophilicity. Therefore, the attached water droplets are uniformly formed into a water film. Thereby, sufficient antifogging property is exhibited even when used in a bathroom space with a lot of steam. (2) If water is applied beforehand by a shower or the like immediately before use in order to exhibit high hydrophilicity, a water film is formed on the surface. When this water film is present, even in a bathroom space where the load of dirt is large, the mirror surface has much better affinity for water than the dirt component, so that the antifouling property is exhibited. In the bathroom space, this property can be used because there is no problem even if the floor gets wet with water. Just before use, simply apply water in advance for a long time each time with a shower or the like. It is possible to prevent not only the cloudiness but also a decrease in visibility due to the adhesion of soap or the like. Further, dirt in the air adhered when not in use is also washed away by the above-described shower or the like. (3) Since the uneven structure is very fine, bacteria and fungi that easily live in the bathroom cannot enter the unevenness. Therefore, contamination by bacteria and fungi is also prevented. (4) Since a hard layer made of an inorganic oxide is formed, the mirror surface is hardly damaged. Therefore, it is possible to prevent the visibility of the mirror from being lowered due to the occurrence of scratches. The height of the irregularities on the substrate surface,
The width and surface roughness can be determined using an atomic force microscope. When measuring a complex and fine uneven surface, the adsorbed water on the surface and the gas entering the surface interfere with each other, and accurate values cannot be obtained with a contact-type surface roughness meter. The measurement is preferably performed using a force microscope.
The height and width of the irregularities are １ ／ of the wavelength of visible light, that is,
It is preferable that the thickness be 200 nm or less. This is because coloration of the surface layer due to light interference can be prevented, and the texture of the substrate is not impaired. The height and width of the unevenness are preferably 0.4 nm or more. This is because sufficient mechanical strength can be secured. The surface roughness is mainly determined by the height of the unevenness, and the surface roughness (Ra) = height / 4 in the schematic surface cross section shown in FIG. Here, since the height of the unevenness is preferably 0.4 nm or more and 200 nm or less, the surface roughness is 0.1 nm or more and 50 nm or less.
m or less is preferable.

According to the present invention, there is further provided a bathroom antifogging mirror, characterized in that the hydrophilic inorganic oxide layer having the concavo-convex structure contains an alkali metal silicate. According to this, by controlling its gradually melting property, it can self-clean the mirror surface for a long time, prevent dirt from sticking without trouble, and easily repeat the clean and highly hydrophilic surface. Reproduce and maintain good antifogging and antifouling properties for a long time.

According to the present invention, there is further provided a hydrophilic composite material characterized in that the uneven structure is a fractal structure. The fractal structure is a multi-level uneven structure including a large-period uneven structure on the surface of the base material and a small-period uneven structure in the structure. By using a fractal structure, that is, a complex structure having finer irregularities in the irregularities, it is possible to increase the water retention ability of the substrate surface and to express a higher degree of hydrophilicity.

[0008] In a preferred aspect of the present invention, the substrate is formed by chemical etching. According to the chemical etching, a clear reflection image without a double image can be obtained.

In a preferred aspect of the present invention, the substrate is formed by immersion in warm water. According to the immersion in warm water, since a chemical solution or the like is not used, irregularities can be formed safely and easily.

[0010] In a preferred aspect of the present invention, the base material is provided with a layer which is bonded to the surface of the base material and contains one or more metal oxides. By including one or more metal oxides, desired irregularities exhibiting high hydrophilicity can be easily formed.

In a preferred aspect of the present invention, the thickness of the layer is set to 400 nm or less. With the above thickness, a transparent film having excellent anti-fogging property and free from light interference and white turbidity can be formed.

In a preferred embodiment of the present invention, the layer is formed by a sol coating method. According to the sol coating method, there is no restriction on equipment depending on the size and shape of the base material, so that a film can be easily formed on the base material surface without requiring special equipment.

In a preferred embodiment of the present invention, the layer is formed by vacuum deposition. According to vacuum deposition, a transparent film having uniform and excellent antifogging properties can be formed regardless of the type of the base material and the type of the oxide used.

In a preferred embodiment of the present invention, the layer is formed by sputtering. According to sputtering, a uniform and strong film can be formed.

In a preferred aspect of the present invention, the layer is formed by CVD. According to CVD, a film having better durability can be formed.

In a preferred embodiment of the present invention, the metal oxide is selected from the group consisting of silica, alumina, zirconia, titania, tin oxide and zinc oxide. By using these oxides, a highly hydrophilic surface having excellent water resistance and chemical resistance can be obtained. Among these metal oxides, it is preferable to use zirconia, titania, tin oxide, and zinc oxide having photocatalytic activity.
By doing so, a higher degree of hydrophilicity can be obtained by indoor lighting or ultraviolet rays from windows.

In a preferred embodiment of the present invention, an alkali metal silicate is further formed on a surface having a concavo-convex structure, and an average of concavities and convexities at an arbitrary position on the outermost surface measured by an atomic force microscope. Height and average width
A layer having a center line average surface roughness Ra of 0.1 nm or more and 50 nm or less. More preferably, the average height of unevenness is 0.1.
8 nm or more and 40 nm or less, unevenness average width 9 nm or more and 100
nm or less, center line average surface roughness Ra 0.1 nm or more and 10
nm or less. By forming more irregularities on the surface on which irregularities have been formed in advance, a better hydrophilic surface can be obtained. Further, even if the surface has interference fringes and cloudiness, there is also an effect of eliminating these and making the surface transparent. Although the uneven structure on the surface is not limited, it is more preferable that the structure described in claims 1 to 18 is formed.

In a preferred embodiment of the present invention, the uneven layer is formed by a sol coating method. This is because sols of metal oxides having various particle diameters and properties can be obtained, so that an appropriate sol can be selected according to the unevenness of the substrate formed in advance.

In a preferred embodiment of the present invention, the uneven layer is preferably formed by sputtering. According to sputtering, a uniform and strong film can be formed.

In a preferred embodiment of the present invention, the uneven layer is formed by CVD. According to CVD, a film having better durability can be formed.

In a preferred embodiment of the present invention, the metal oxide forming the uneven layer is preferably selected from the group consisting of silica, alumina, zirconia, titania, tin oxide and zinc oxide. By using these metal oxides, it is easy to obtain unevenness having good hydrophilicity. Among these metal oxides, it is preferable to use zirconia, titania, tin oxide, and zinc oxide having photocatalytic activity. By doing so, a higher degree of hydrophilicity can be obtained by indoor lighting or ultraviolet rays from windows.

In a preferred embodiment of the present invention, the two-dimensional cross-sectional structure of the concave and convex holes is such that the surface portion is widest and becomes narrower toward the back. If the two-dimensional cross-sectional structure of the hole has a shape such that the surface portion is the widest and the depth becomes narrower as it goes deeper, it is easy to remove dirt and maintain good hydrophilicity.

In a preferred aspect of the present invention, the mirror has a hydrophilicity such that a receding angle with water on the vertical surface is 20 degrees or less. This is because water adhered to the mirror surface in an upright manner shows a droplet property, and it is easy to exhibit antifouling properties, antifogging properties, waterdrop formation preventing properties, and waterdrop adhesion preventing properties over the entire mirror surface. The term “dropping property” refers to a state in which a water film is formed on a mirror surface in an upright surface such as a bathroom wall without being formed as a water droplet when water is applied. The receding angle is the contact angle of water when a sample is immersed in a water tank at a constant speed and pulled up.

In a preferred embodiment of the present invention, an antibacterial substance is carried on the outermost surface of the composite material. By carrying a substance having antibacterial properties, it kills bacteria and microorganisms that are one factor that inhibits hydrophilicity,
Alternatively, since propagation can be suppressed, good hydrophilicity can be maintained.

In a preferred embodiment of the present invention, the zeta potential in water near pH 7 on the surface of the composite material is made negative. By making the zeta potential negative, it becomes possible to provide a bactericidal and / or antifouling effect when water comes into contact with the mirror surface. It is known that dirt and fungi around water are generally negatively charged in water near pH 7. Therefore, by making the zeta potential of the surface of the composite material negative, the surface of the composite material and the dirt and fungi are electrically repelled in a state of contact with water, and the adhesion of dirt and fungi can be prevented.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The anti-fog mirror of the present invention
Especially in an environment where the amount of added dirt is large and water vapor and water are constantly applied, especially in bathrooms and shower rooms, excellent antifogging, dripproof, antifouling, and self-cleaning hydrophilicity for bathrooms It can be suitably used as an anti-fog mirror.

In the present invention, the method of forming the irregularities on the surface of the substrate is not limited, and may be selected from known methods, including sol coating, plating, and CVD.
Method of forming a film having fine irregularities on the substrate surface as shown in FIG. 2 by a method, sputtering, vacuum deposition method, etc., and forming irregularities directly on the substrate as shown in FIG. 3 by sandblasting, etching, etc. And a method of forming fine irregularities on a mold and transferring the irregularities to a substrate. After forming the irregularities on the surface of the transparent base material, the reflective coating may be applied to the back surface to form a mirror, or the reflective coating may be applied first to the back surface to form a mirror and then the unevenness may be formed.

In the present invention, sodium silicate, potassium silicate, lithium silicate and ammonium silicate can be suitably used as the alkali metal silicate.

In the present invention, it is preferable to form irregularities on the substrate surface by chemical etching. Chemical etching is a method in which a substrate is immersed in a solution of, for example, an acid, an alkali, or a peroxide or brought into contact with steam generated when the solution is heated, and a surface treatment is performed by a chemical reaction. Examples of the solution to be used include aqueous solutions of hydrochloric acid, sulfuric acid, ammonium sulfide, hydrofluoric acid, boron fluoride, hydrofluoric acid and the like.

In the present invention, it is preferable to form irregularities on the substrate surface by immersion in warm water. According to warm water immersion,
Since a chemical solution or the like is not used, irregularities can be formed safely and easily. The water can be pure or tap water. The water temperature may be 40 ° C. or higher, and preferably 60 ° C. or higher in consideration of the processing time.

In the present invention, it is preferable to coat a layer containing at least one metal oxide on the surface of the substrate.
According to this, desired irregularities exhibiting high hydrophilicity can be easily formed. As a method of coating the oxide, a sol coating method, vacuum deposition, sputtering,
The method may be selected from known methods such as a CVD method and a plating method, and may be other methods. According to the sol coating method, since there is no restriction on the equipment depending on the size and shape of the base material, the sol coating method can be easily performed without requiring special equipment. According to the CVD method, sputtering, and vacuum deposition, application to a large base material is restricted by equipment, but a uniform and stable thin film can be formed. By increasing the treatment temperature in these methods, it is possible to further improve the durability such as alkali resistance and hot water resistance.

In the present invention, the thickness of the oxide film is set to 400 nm or less. In particular, when a film having a thickness of more than 400 nm is formed using one kind of oxide, interference fringes, turbidity, and the like due to light interference occur, and defects in appearance are likely to occur. Also, as the film thickness increases, the abrasion resistance decreases, and it is inevitable that the film is easily damaged.

Here, as the metal oxide, silica, alumina, zirconia, ceria, yttria, boronia,
Magnesia, calcia, ferrite, hafnia, titanium oxide, zinc oxide, tungsten trioxide, ferric oxide, cuprous oxide, cupric oxide, bismuth trioxide, tin oxide,
Single oxides such as nickel oxide, cobalt oxide, barium oxide, strontium oxide, and vanadium oxide, and barium titanate, calcium silicate, water glass, aluminosilicate, calcium phosphate, strontium titanate,
Composite oxides such as potassium titanate, barium titanate, calcium titanate, and aluminosilicate can be suitably used. Among them, it is preferable to use any of silica, alumina, zirconia, titania, tin oxide, and zinc oxide. Silica and alumina are preferred for forming small and fine irregularities, and zirconia and
Titania, tin oxide and zinc oxide are preferred. In the sol coating method, silica, from which various things can be obtained regarding the particle diameter and the sol properties described below, is preferable. Silica is the cheapest and very practical. In addition, silica, zirconia, and the like having a negative zeta potential in water near pH 7;
High hydrophilicity can be obtained by using titania and tin oxide. Preferably, silica having the lowest surface potential is used, and the use of silica can provide a higher degree of hydrophilicity.

In the present invention, the metal oxide particles are preferably in the form of a sol dispersed colloidally in water or a hydrophilic solvent. The hydrophilic solvent is not particularly limited as long as it can stably disperse the metal oxide and form a uniform and smooth film on the substrate, but is preferably an organic solvent having a boiling point of 200 ° C. or lower. Solvents can be mentioned. Examples of preferred organic solvents include methanol, ethanol, n-propanol, isopropanol, t-butanol, isobutanol, and n-butanol.
2-methylpropanol, pentanol, ethylene glycol, monoacetone alcohol, diacetone alcohol, ethylene glycol monomethyl ether, 4-
Hydroxy-4-methyl-2-pentanone, dipropylene glycol, propylene glycol, tripropylene glycol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-propoxy -2-propanol, propylene glycol monomethyl ether,
Alcohol solvents such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, and 2-butoxyethanol, and hydrocarbon solvents such as n-hexane, toluene, xylene, and mineral spirits Examples of the solvent include ester solvents such as methyl acetate, ethyl acetate, and butyl acetate.

In the present invention, when a film is formed on the surface of the base material by the sol coating method, the metal oxide is used in an amount of 0.0
It is preferable to use a coating composition containing 5 to 20 parts by weight and 99.95 to 80 parts by weight of a solvent. By coating the coating solution on the surface of the base material, a transparent film having excellent antifogging properties and free from light interference and white turbidity can be formed.

In the case of the sol coating method, a granular metal oxide having an average particle diameter of 1 to 100 nm, an average diameter of 1 to 50 n
m, a chain metal oxide having an average length of 10 to 1000 nm, and a feather or rod-shaped metal oxide having an average diameter of 1 to 50 nm and an average length of 10 to 500 nm are preferably used. Examples of the granular metal oxide having an average particle diameter of 1 to 100 nm include silica and zirconia, and an average diameter of 1 to 50 n.
m, as the chain metal oxide having an average length of 10 to 1000 nm, silica, alumina, etc., an average diameter of 1 to 50 nm,
Examples of the feather-like or rod-like metal oxide having an average length of 10 to 500 nm include alumina and titania. If a chain-like, feather-like, or rod-like metal oxide is used, the durability of the film formed on the substrate surface can be improved. Also,
When a granular inorganic oxide is used, a film having desired unevenness and higher smoothness can be formed.

In the present invention, the base material surface layer preferably contains a binder for fixing the metal oxide on the base material surface. This is because the binder improves the adhesion to the substrate surface, and provides higher durability and abrasion resistance. As the binder, an inorganic binder such as glaze, water glass, and silicone, and an organic binder such as a thermosetting resin, a photocurable resin, and a thermoplastic resin can be used.

In the present invention, the coating solution may contain a surfactant. Examples of surfactants that can be added include polyoxyethylene alkylphenyl ether ammonium sulfonate, sodium polyoxyethylene alkylphenyl ether sodium sulfonate, fatty acid soap, fatty acid sodium soap, dioctyl sodium sulfosuccinate, Alkyl sulfate, alkyl ether sulfate, alkyl sulfate soda salt, alkyl ether sulfate soda salt, polyoxyethylene alkyl ether tersulfate, polyoxyethylene alkyl ether tersulfate Da salt,
Alkyl sulfate TEA salt, polyoxyethylene alkyl ether sulfate TEA salt, 2-ethylhexyl alkyl sulfate sodium salt, sodium acylmethyltaurate, sodium lauroylmethyltaurate, sodium dodecylbenzenesulfonate, lauryl sulfosuccinate Disodium, disodium lauryl polyoxyethylene sulfosuccinate, polycarboxylic acid, oleoyl sarcosine, amide ether sulphate
Anionic surfactants such as sodium, lauroyl sarcosine and sodium sulfo FA ester; polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene acetyl ether, polyoxyethylene stearyl Ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether
Ter, polyoxyethylene alkyl ester, polyoxyethylene alkyl phenol ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene laura
Polyoxyethylene stearate, polyoxyethylene alkylphenyl ether, polyoxyethylene oleate, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, polyether-modified silicone, polyester-modified silicone Sorbitan laurate, sorbitan stearate, sorbitan palmitate, sorbitan sesquioleate, sorbitan oleate, polyoxyethylene sorbitan laurate,
Polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan oleate, glycerol stearate,
Polyglycerin fatty acid ester, alkyl alkylamide, lauric acid diethanolamide, oleic acid diethanolamine, oxyethylene dodecylamine, polyoxyethylene dodecylamine, polyoxyethylene alkylamine, polyoxyethylene octadecylamine, polyoxyethylene alkyl Propylene diamine,
Nonionic surfactants such as polyoxyethylene oxypropylene block polymer and polyoxyethylene stearate; amphoteric surfactants such as dimethyl alkyl betaine, alkyl glycine, amido betaine and imidazoline; octadecyl dimethyl benzyl ammonium chloride, alkyl dimethyl Benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, dioleyl dimethyl ammonium chloride, 1
-Hydroxy-2-alkylimidazoline quaternary salt, alkylisoquinolinium bromide, polymer amine, octadecyltrimethylammonium chloride, alkyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, alkylimidazoline Cationic surfactants such as quaternary salts, dialkyldimethylammonium chloride, octadecylamine acetate, tetradecylamine acetate, alkylpropylenediamine acetate, and didecyldimethylammonium chloride.

In the present invention, the method of applying the coating solution on the surface of the substrate may be appropriately selected from known methods.
Spray coating method using air gun, airless gun, aerosol spray, etc., spin coating method,
Examples include, but are not limited to, dip coating, flow coating, roll coating, brush coating, and sponge coating. In addition, various shampoos, primers, detergents, compounds, antistatic agents, and the like can be used as a treatment before applying the coating liquid to the substrate surface.

The heat treatment after applying the coating solution to the surface of the base material may be appropriately performed according to the type and properties of the coating solution and the base material, and may be any method such as natural drying, heating, and infrared / ultraviolet irradiation. In some cases, the solvent may simply be evaporated and dried. As a method of performing the heat treatment, the surface treatment agent is applied to the surface of the article and then the heat treatment is performed. The number of times of the application and the heat treatment may be two or more. There are various methods such as performing heat treatment at once after repeating application only a plurality of times and performing a series of operations of coating and heat treatment a plurality of times.

In the present invention, as shown in FIG. 4, it is possible to further form an uneven layer made of a metal oxide on the surface of the base material on which the unevenness has been formed in advance. The concavities and convexities formed in advance may be selected by a known method, but as described above, the sol coating method, the vacuum deposition method, the sputtering,
It is preferable to form by VD, and it is preferable that the uneven structure falls within the range of the height, width and surface roughness of the unevenness. The metal oxide forming the uneven layer may be selected from the above-described metal oxides, and it is particularly preferable to use silica, alumina, zirconia, titania, tin oxide, and zinc oxide. Of these metal oxides,
It is preferable to use one having photocatalytic activity, such as zirconia, titania, tin oxide, and zinc oxide. The hydrophilicity of the photocatalyst makes it possible to further enhance the hydrophilicity in the presence of ultraviolet light obtained from indoor lighting, incident light from windows, and the like. Further, the effect of decomposing and deodorizing can be expected by the decomposition function of the photocatalyst. It is preferable to use these oxide sols and form them by a sol coating method. Sols having various particle diameters and properties are available, and an optimum sol can be selected so as to enter the concave portions formed on the surface. The oxide sol includes the various metal oxides described above, and among them, those having a particle diameter of 50 nm or less are preferable. This is because the surface of the base material surface is increased because of entering the unevenness formed in advance, and the hydrophilicity is further enhanced. Further, a method of forming the oxide film by sputtering or CVD is also preferable. According to the sputtering or the CVD, it is possible to form a film utilizing the unevenness of the hydrophilic composite material before forming the film.
By increasing the processing temperature in CVD or sputtering, it is possible to further improve durability such as alkali resistance and hot water resistance.

Further, metal particles can be fixed to the outermost surface of the substrate by a photoreduction method. In this case, the hydrophilic function can be enhanced by adding a metal having an electron capturing effect. Metals having an electron trapping effect include Pt, Pd, Au, Ag, Cu, Ni, Fe, C
It refers to metals such as o and Zn which have a small ionization tendency and are easily reduced. These metals may be used in combination. The average particle diameter of these metals is preferably 200 nm or less. This is to prevent color formation and white turbidity due to light interference and irregular reflection.

It is also possible to fill the gaps between the metal oxide layer particles formed on the substrate surface with particles having a smaller particle size than the gaps. By filling the gaps with particles, the surface area of the substrate surface can be increased, which leads to improvement in hydrophilicity. In addition, the particles filled in the gaps can bind the metal oxide layer particles, and the adhesion to the base material is improved. As particles having a particle size smaller than the gap,
Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, P
d, Ni and the like. If the metal having the electron capturing effect is filled, further improvement in hydrophilicity can be expected.

It is also possible to carry a substance having antibacterial properties on the outermost surface of the composite material. Here, the substance having antibacterial properties may be an organic substance or an inorganic substance. Considering durability such as abrasion resistance, hot water resistance and chemical resistance, P
It is preferable to use metals such as t, Au, Ag, and Cu, or compounds thereof. By carrying these substances having antibacterial properties, it is possible to kill bacteria or microorganisms, which are one factor that inhibits hydrophilicity, or to suppress the proliferation, so it is very effective in maintaining hydrophilicity It is.

[0045]

EXAMPLES Example 1 Chain Colloidal Silica 1% Chain colloidal silica (solids concentration 15-16%, pH
(2-4, particle diameter 40-100 nm) was diluted with ethanol to prepare a 1% by weight coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples.
Table 1 shows the results.

Example 2: Chain Colloidal Silica 20% Chain Colloidal Silica (solids concentration 15-16%, pH
(2-4, particle diameter 40-100 nm) as it was in a stock solution, contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. The receding angle was 15 degrees, and there was an initial dropping property. Table 1 shows the results.

Example 3 Spherical Colloidal Silica 1% Spherical colloidal silica (solid content 30 to 31%, particle size 8 to 11 nm);
g was added and diluted with water to prepare a 1% by weight coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Example 4 Spherical Colloidal Silica 1% Spherical colloidal silica (solid content: 30 to 31%, particle size: 8 to 11 nm) was diluted with water to prepare a 1% by weight coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. Using the above sample,
The following five items were evaluated. Table 1 shows the results.

Example 5: Alumina sol 1% rod-shaped alumina sol (solids concentration 20 to 22%, particle size 1
(0 to 20 nm) was diluted with ethanol to prepare a 1% by weight coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Example 6: Zirconia sol 1% A spherical zirconia sol (solid content: 30 to 31%, particle size: 60 to 70 nm) was diluted with ethanol to prepare a 1% by weight coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Example 7: 1% titania sol Anatase type titania sol (solid content: 10%) was diluted 10 times with water to prepare a coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Example 8: Lithium silicate Lithium silicate (SiO ₂ solid concentration 20 to 21)
%, Li ₂ O solid content concentration of _{2 to} 3.5%)
The sample was applied to a 10 cm square mirror by being included in a cloth, and was naturally dried to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Example 9: Binder addition Spherical colloidal silica (solid content: 30 to 31%, particle size: 8 to 11 nm); 10 g, polyvinyl alcohol 5%
Aqueous solution (manufactured by Nippon Synthetic Chemical Co., Ltd., NH26); 2 g, silane coupling agent (manufactured by Nippon Unicar Co., Ltd., A110
0); 0.02 g, surfactant; 0.4 g, water; 90 g
Was mixed to prepare a coating solution. The coating solution was contained in a cloth, applied to a 10 cm square mirror, and dried naturally to obtain a sample. The following five items were evaluated using the above samples. Table 1 shows the results.

Comparative Example 1: Mirror For comparison with the above-described embodiment, no treatment was performed.
A 0 cm square mirror was prepared, and the following five items were evaluated. The receding angle was 22 degrees, and there was no initial drip property. Table 1 shows the results.

Evaluation Items 1. Surface roughness (Ra), average height of unevenness (H), average width of unevenness (L): Measured in an AFM (atomic force microscope) mode of a scanning probe microscope (D3000 manufactured by Digital Instruments). 2. Anti-fogging property: Stored in a refrigerator (about 0 ° C.) for 5 minutes, and then left in an atmosphere of 28 ° C. and 81% humidity to check the surface for fogging. ◎: Not fogged at all and does not affect the reflected image, ：: No fogging, but slightly reflected image, Δ: Slightly fogged, X: Clearly fogged. 3. Dropping property: Place the sample on a vertical surface, pour water on it, and visually check the state of water wetting after 1 minute. ◎: 100% wet area, ○: 80% or more wet area 1
Less than 00%, Δ: 60% or more and less than 80% of water-wetted surface, ×:
Evaluated in 4 steps of less than 60% water wet area. 4. Abrasion resistance: Sliding with a sponge and checking for abnormalities in appearance. ◎: No abnormality at all, ：: Slight scratches that can be seen when exposed to light, △: Shallow scratches, X: Deep scratches reaching the substrate, evaluated on four levels. 5. Cleanability: After applying artificial grime to the sample, spray it with water by spraying to check the dirt removal. ◎: The dirt is completely removed by one spraying of water, ○: The dirt is completely removed by three to four sprays of water, Δ: 3 to 4 spraying
The dirt is slightly left with the water, but the dirt remains.

[0056]

[Table 1]

As can be seen from Table 1, it was confirmed that by applying various sols to the surface of the substrate, good antifogging property, drip property and cleaning property were exhibited. In addition, regarding the particle shape, it was confirmed that the chain sol had better wear resistance than the spherical sol. Further, when a spherical sol was used, it was confirmed that the abrasion resistance was improved by adding a binder.

Example 10 Evaluation at Various Solid Concentrations Chain colloidal silica (solids concentration 20%, particle diameter 40)
-100 nm) with a silica solids concentration of 20% (no dilution)
Coating solutions having various concentrations of 0.01% were prepared. Each sponge of 10 g / m ² is coated with the coating solution having various concentrations,
It was applied to a transparent glass plate to obtain a sample. The various samples prepared as described above were evaluated for transparency, anti-fogging property, and dropping property. The antifogging property and the dropping property were evaluated in the same manner as in Examples 1 to 9. Regarding transparency, ◎: interference fringes are not seen in any way, ○: interference fringes are seen slightly when exposed to light, Δ: there are interference fringes, ×: there are interference fringes and white turbidity. Was evaluated. In addition, workability for coating was evaluated so as to satisfy the above three items. Table 2 shows the evaluation results.

[0059]

[Table 2]

As can be seen from Table 2, in the case of the sol coating method, it can be confirmed that the solid content concentration for satisfying all of the transparency, anti-fogging property and dropping property is 20% to 0.05%. Was.

Example 11 Evaluation of Antifogging and Antifouling of Various Films Silica was coated on a polyethylene terephthalate (PET) film by DC reactive sputtering. This film was adhered to a mirror to obtain Sample 1. Similarly, silica was coated on the PET film by EB evaporation. This film was adhered to a mirror to obtain Sample 2. Similarly, alumina was coated on a PET film by EB evaporation. This film was adhered to a mirror to obtain Sample 3. For comparison, the PET films as the substrates of Samples 1 to 3 were also adhered to a mirror to obtain comparative samples.

The following evaluations were performed on these samples. 1. Surface roughness (Ra), average height of unevenness (H), average width of unevenness (L): Measured in an AFM (atomic force microscope) mode of a scanning probe microscope (D3000 manufactured by Digital Instruments). 2. Anti-fogging property: Stored in a refrigerator (about 0 ° C.) for 5 minutes, and then left in an atmosphere of 28 ° C. and 81% humidity to check the surface for fogging. The initial antifogging property and the antifogging property after one week exposure were evaluated. ◎: Not fogged at all and does not affect the reflected image, ：: No fogging, but slightly reflected image, Δ: Slightly fogged, X: Clearly fogged. 3. Antifouling property: Stain adhesion after exposure for one week was visually checked. ：: No contamination was observed, and the initial cleanliness was maintained.
：: Slightly adhered, but does not affect use. △: Dirty adhered and there is a part where the mirror is difficult to see. ×: Surface is cloudy with dirt. Rated on a scale. The sample was exposed for one week under a mirror in an 80 cm square shower booth, and repeated bathing of four persons per day was performed. Table 3 shows the evaluation results.

[0063]

[Table 3]

As can be seen from Table 3, the comparative sample had no antifogging property at all. On the other hand, all of Samples 1 to 3 showed good antifogging properties without affecting the reflection image both after the initial exposure for one week. Further, regarding the antifouling property, the surface of the comparative sample became cloudy due to adhesion of dirt. On the other hand, sample 1
No contamination was observed in any of Nos. 1 to 3, and the initial cleanliness was maintained. It was confirmed that good antifogging and antifouling properties can be obtained by coating the substrate with an inorganic oxide of silica or alumina by DC reactive sputtering or EB vapor deposition to form irregularities.

Example 12: Hydrofluoric acid treatment (chemical etching) A 20 cm square mirror surface was chemically etched with hydrofluoric acid to form fine irregularities to obtain a sample. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, good anti-fogging properties without affecting the reflected image were exhibited in both the initial and one-week exposure. Further, no stain was attached, and the initial cleanliness was maintained. From this, it was confirmed that good antifogging property and antifouling property can be obtained by forming irregularities on the surface by hydrofluoric acid treatment.

Example 13 Treatment with Hydrofluoric Acid Solution (Chemical Etching) A 20 cm square mirror was treated with a hydrofluoric acid solution to form fine irregularities to obtain a sample. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, good anti-fogging properties which did not affect the reflection image were exhibited both after the initial exposure for one week. Further, no stain was attached, and the initial cleanliness was maintained. From this, it was confirmed that good antifogging property and antifouling property can be obtained by forming irregularities on the surface by treatment with hydrofluoric acid solution.

Example 14: CVD method (tin oxide) A 20 cm square mirror surface was coated with tin oxide by a CVD method to obtain a sample. This sample was divided into three equal parts, and the same evaluation as in Example 11 was performed using one sheet. The remaining two sheets were evaluated for warm water resistance and alkali resistance. Warm water resistance was evaluated by immersing in 95 ° C. warm water for 12 hours and then visually checking for abnormal appearance. Alkali resistance was evaluated by immersing in 5% NaOH for 12 hours. It was performed by a method of visually confirming the presence or absence of an abnormality. Warm water resistance,
The same evaluation as in Example 11 was performed using the sample for which the alkali resistance was evaluated. Table 3 shows the evaluation results.

As can be seen from Table 3, both in the initial stage and after one week of exposure, good antifogging properties without affecting the reflected image were exhibited. Further, no stain was attached, and the initial cleanliness was maintained. No abnormality due to warm water or alkali was observed,
It was confirmed that the antifouling property was not affected. From this, it was confirmed that by forming tin oxide by coating the tin oxide by the CVD method, the anti-fogging property and anti-fouling property resistant to hot water and alkali can be obtained.

Example 15: Treatment of Uneven Surface with Inorganic Oxide Sol By treating with a hydrofluoric acid solution, a mirror surface with fine unevenness was formed on the mirror surface to obtain spherical colloidal silica (solid content: 30 to 31%, particle size: 8-11 nm), lithium silicate, and a mixture of the above-mentioned spherical colloidal silica and the above-mentioned lithium silicate were coated with three types of sols, respectively, to obtain three types of samples. At the time when the irregularities were formed on the mirror surface, slight turbidity was observed,
By coating the sols of any kind, no interference fringes or white turbidity were observed even when the surface was exposed to light. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, both in the initial stage and after exposure for one week, good antifogging properties without affecting the reflected image were exhibited. Further, no stain was attached, and the initial cleanliness was maintained. From this, by forming a coating with a metal oxide on the surface of the substrate on which the unevenness has been formed in advance, and making the unevenness,
It was confirmed that good antifogging and antifouling properties were obtained.

Example 16: Treatment of Titanium Oxide Sol on Irregular Surface An anatase titania sol (solid content: 15%) was diluted 15 times with ethanol to prepare a coating solution. The coating solution was applied by a flow coating method to a mirror surface having fine irregularities formed by a hydrosilicofluoric acid solution treatment, and naturally dried to obtain a sample. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, both the initial and after one week of exposure exhibited good antifogging properties without affecting the reflected image. Further, no stain was attached, and the initial cleanliness was maintained. From these results, it was confirmed that good antifogging and antifouling properties can be obtained by further applying a metal oxide sol to the surface of the substrate on which the unevenness has been formed in advance to form the unevenness.

Example 17: Treatment of uneven surface with alkoxide Titanium alkoxide solution (NDH510, manufactured by Nippon Soda)
C, solid content concentration 5%) was diluted twice with ethanol to prepare a coating solution. The coating solution was applied by a flow coating method to a mirror surface having fine irregularities formed by hydrofluoric acid solution treatment, and baked at 500 ° C. for 30 minutes to obtain a sample. Using this sample, the same evaluation and abrasion resistance as in Example 11 were performed. Evaluation of abrasion resistance was performed in Example 1.
-9 was performed in the same manner. Table 3 shows the evaluation results.

As can be seen from Table 3, both in the initial stage and after one week of exposure, good antifogging properties without affecting the reflected image were exhibited. Further, no stain was attached, and the initial cleanliness was maintained. In the wear resistance evaluation, no damage was found. From this, it was confirmed that the surface of the substrate on which the irregularities had been formed in advance was further coated with a metal oxide and fired to form the irregularities having good wear resistance. It was also confirmed that good antifogging and antifouling properties were obtained.

Example 18: Sputtering treatment of uneven surface A silica sample was coated by a vacuum evaporation method, and a 20 cm square mirror surface on which unevenness was previously formed was further coated with titania by sputtering to obtain a sample. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, both in the initial stage and after one week of exposure, good antifogging properties without affecting the reflected image were exhibited. Further, no stain was attached, and the initial cleanliness was maintained. From these results, it was confirmed that more excellent antifogging property and antifouling property can be obtained by further providing irregularities on the substrate surface having irregularities formed by vacuum deposition.

Example 19: Sputtering treatment 2 for uneven surface The titania was coated by sputtering, and a 20 cm square mirror surface on which predetermined unevenness was formed was further coated with tin oxide by sputtering to obtain a sample. The same evaluation as in Example 11 was performed using this sample. Table 3 shows the evaluation results.

As can be seen from Table 3, both in the initial stage and after one week of exposure, good antifogging properties without affecting the reflected image were exhibited. Further, no stain was attached, and the initial cleanliness was maintained. From these results, it was confirmed that more favorable anti-fogging property and anti-fouling property could be obtained by further providing irregularities on the surface of the base material having irregularities formed by sputtering.

Example 20: Relationship between film thickness and antifogging and antifouling properties A 20 cm square mirror surface was coated with titania in various thicknesses by sputtering to obtain samples. Using this sample, antifogging and antifouling properties were evaluated in the same manner as in Example 11. The appearance was also evaluated. The method is described in Example 1
Same as 9. Table 4 shows the evaluation results.

[0082]

[Table 4]

As can be seen from Table 4, there is no difference in the antifogging and antifouling properties due to the difference in the film thickness within the range of this experiment, but when the film thickness is 500 nm, interference fringes are observed and there is a problem in appearance. Was. From this, it was confirmed that the film thickness was preferably 400 nm or less.

Example 21 Five kinds of metal oxide sols of alumina sol, silica sol, tin oxide sol, titania sol, and zirconia sol were coated on the mirror surface, respectively, to obtain samples. Surface roughness (Ra), average height of unevenness (H), average width of unevenness (L) of each sample
After measuring the zero-charge point, the sample was placed in a bathroom and exposed for 2 weeks. During the exposure period, bathing was performed by four persons a day, and no intentional watering or washing of the mirror surface was performed. For comparison, a normal mirror was similarly installed and exposed.
The zero charge point is defined as the p of the aqueous solution when the zeta potential becomes zero.
H, and the zeta potential is negative when placed in an aqueous solution having a pH higher than the value of the zero charge point, and becomes positive when placed in an aqueous solution having a lower pH. Measurement of the zero charge point on the mirror surface was performed using a laser zeta potentiometer (ELS-6000, manufactured by Otsuka Electronics).
The electroosmotic flow was measured using polystyrene latex as monitor particles for light scattering, and the pH of the aqueous electrolyte solution when the electroosmotic flow became 0 was determined by titration. Surface roughness (Ra), average height of unevenness (H), average width of unevenness (L)
Was measured in an AFM (atomic force microscope) mode of a scanning probe microscope (D3000 manufactured by Digital Instruments). Samples were removed from the bathroom after two weeks of exposure,
According to the dropping property evaluation method of Examples 1 to 9, 4
A grading was performed. The results are shown in the table below.

[0085]

[Table 5]

As can be seen from Table 5, the normal mirror has a zero charge point equivalent to that of the silica sol mirror, but has a water wet area of 60%.
Less than. On the other hand, in the mirrors coated with various sols, the alumina mirror is 60% or more, and the tin oxide / zirconia mirror is 80% or more.
% Or more, and the silica mirror showed a water wetted area of 100%. From the above, it was confirmed that it was difficult to maintain hydrophilicity only by a small value of the zero charge point (negative zeta potential) or only by fine irregularities. That is, by combining the fine irregularities with the zero charge point being less than 7 (the zeta potential is negative in water near pH 7), the lower the zero charge point, the better the hydrophilicity is maintained. It was confirmed that the formation of a water film provided antifogging properties, antifouling properties, waterdrop formation preventing properties, and waterdrop adhesion preventing properties.

Example 22 A mirror was immersed in hot water at 80 ° C. for 24 hours, and then dried naturally to obtain a sample. This sample was evaluated in the same manner as in Example 19. As a result, the surface roughness (Ra) was 0.675.
nm, the average height of unevenness (H) was 3.094 nm, and the average width of unevenness (L) was 24.899 nm. The initial antifogging property, the antifogging property after exposure and the antifouling property were evaluated as ◎,
It was confirmed that good antifogging property and cleanliness can be maintained after exposure. From this, it was confirmed that good antifogging property and antifouling property can be obtained by forming irregularities on the substrate surface by immersing in hot water.

Example 23 A 200 mm × 300 mm mirror was prepared. A sample having irregularities formed by applying silica sol was obtained. After forming irregularities with silica sol, a silver nitrate aqueous solution was applied thereon, and a sample in which silver was photoreduced and fixed using a BLB lamp was obtained. For comparison,
A sample having silver fixed directly on the mirror surface was also prepared. After measuring the surface roughness (Ra), the average height of the unevenness (H), and the average width of the unevenness (L) of these samples, mold spores were attached to the surface, placed in a bathroom, and exposed for 2 weeks. Was. Bathing during the exposure period was 4 people a day. Two weeks later, the state of adhesion of dirt and the occurrence of mold was confirmed, and the dropping property was evaluated in the same manner as in Examples 1 to 9. Table 6 shows the results. In addition, surface roughness (Ra), average height of unevenness (H), average width of unevenness (L)
Was measured in an AFM (atomic force microscope) mode of a scanning probe microscope (D3000 manufactured by Digital Instruments).

[0089]

[Table 6]

As can be seen from Table 6, although no mold was generated on the surface of the comparative sample, dirt was adhered to it, and the water-wetted area was less than 60%. Met. The sample with irregularities formed with silica
Dirt was scarcely adhered, and the droplet wetness was barely maintained at a water wet area of 60% or more. However, mold was spotted on the surface, and the portion lost hydrophilicity, which was not preferable for use. On the other hand, what fixed silver on the irregularities of silica, the surface roughness, average height and width of the irregularities are not much different from the previous sample in which the irregularities were formed with silica, but no mold was attached, 8 wet areas
A good dropping property of 0% or more was maintained. From this, it was confirmed that by fixing silver on the unevenness, it was possible to prevent the occurrence of mold on the surface of the member and thereby maintain the hydrophilicity satisfactorily. From the above, it was suggested that the hydrophilicity can be maintained in a favorable state for a long time by combining the unevenness and the antibacterial metal.

[0091]

According to the present invention, an antifogging property and a drip-proofing property which can be suitably used mainly in a bathroom or a shower room under an environment where a large amount of dirt is added and a large amount of water vapor or water is constantly applied. It has become possible to provide a hydrophilic antifogging mirror for bathrooms having excellent antifouling properties and self-purifying properties.

[Brief description of the drawings]

FIG. 1 shows a schematic cross-sectional view of an uneven surface.

FIG. 2 is a schematic cross-sectional view of a case where a substrate is covered with a metal oxide layer to form irregularities.

FIG. 3 is a schematic cross-sectional view showing a case where irregularities are directly formed on a substrate.

FIG. 4 is a schematic cross-sectional view showing a case where irregularities are further formed on the irregular surface.

[Explanation of symbols]

 H: Height of unevenness L: Width of unevenness 1: Base material 2: Metal oxide layer

Continued on front page (31) Priority claim number Japanese Patent Application No. Hei 11-65024 (32) Priority date March 11, 1999 (1999.3.1.11) (33) Priority claim country Japan (JP) (72) Inventor Kaori Morihara 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture (72) Inventor Shin Hayakawa 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Totoki Co., Ltd. F-term (for reference) 2H042 DB11 DE08

Claims (18)

[Claims] 1. A layer made of a hydrophilic inorganic oxide is formed on a mirror surface having a reflection coating on the back surface, and the layer surface is formed at an arbitrary position on the substrate surface measured by an atomic force microscope. An antifogging mirror for bathrooms having an uneven structure in which the average height and average width of the unevenness are 0.4 nm or more and 200 nm or less, and the center line average surface roughness Ra is 0.1 nm or more and 50 nm or less. . 2. An average height of a concavo-convex structure measured by an atomic force microscope at an arbitrary position on the surface of the layer is 0.8 nm.
Not less than 40 nm and an average width of not less than 9 nm and not more than 100 nm.
Hereinafter, the center line average surface roughness Ra is 0.1 nm or more and 10 n
The antifogging mirror for bathrooms according to claim 1, wherein m is not more than m. 3. The antifogging mirror for a bathroom according to claim 1, wherein the hydrophilic inorganic oxide layer contains an alkali metal silicate. 4. The antifogging mirror for a bathroom according to claim 1, wherein the uneven structure is a fractal structure. 5. The antifogging mirror for a bathroom according to claim 1, wherein the thickness of the layer is 400 nm or less. 6. The metal oxide is silica, alumina,
2. A material selected from the group consisting of zirconia, titania, tin oxide, and zinc oxide.
6. The antifogging mirror for bathroom according to items 5. 7. The bathroom antifogging mirror according to claim 6, wherein, among said metal oxides, zirconia, titania, tin oxide and zinc oxide are photocatalysts. 8. The antifogging mirror for a bathroom according to claim 1, wherein the layer is formed by a sol coating method. 9. The antifogging mirror for a bathroom according to claim 1, wherein said layer is formed by a chemical etching method. 10. The antifogging mirror for a bathroom according to claim 1, wherein the layer is formed by a vacuum deposition method. 11. The bathroom antifogging mirror according to claim 1, wherein the layer is formed by a sputtering method. 12. The bathroom antifogging mirror according to claim 1, wherein the layer is formed by a CVD method. 13. A bathroom anti-fog mirror having a hydrophilic surface, comprising: a layer having the concavo-convex structure; and a layer mainly composed of an alkali metal silicate on the layer.
The average height and average width of the irregularities at an arbitrary position on the layer surface measured by an atomic force microscope are 0.4 nm or more and 2
00 nm or less, and the center line average surface roughness Ra is 0.1
An antifogging mirror for bathrooms, having a thickness of not less than 50 nm and not more than 50 nm. 14. An average height of irregularities on the surface of the layer is 0.8.
nm to 40 nm, average width 9 nm to 100 nm
Hereinafter, the center line average surface roughness Ra is 0.1 nm or more and 10 n
The antifogging mirror for bathrooms according to claim 13, wherein m is not more than m. 15. The antifogging mirror for bathrooms according to claim 1, wherein the zeta potential of the mirror surface is negative in water near pH 7. 16. The mirror according to claim 1, wherein the mirror has a hydrophilicity with a receding angle with respect to water on the vertical surface of not more than 20 degrees.
16. The antifogging mirror for bathroom according to any one of items 15 to 15. 17. The antifogging mirror for a bathroom according to claim 1, wherein the mirror contains a substance having antibacterial properties. 18. The bathroom mirror, wherein an antifouling property and / or antifogging property and / or prevention of water droplet formation over the entire surface by forming a water film on the mirror surface by water or water vapor contacting the mirror surface. The antifogging mirror for a bathroom according to any one of claims 1 to 17, wherein the antifogging mirror has a property of preventing water drops from adhering.