JP2003073146A - Fogging proof mirror and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fogging proof mirror excellent in transparency and a staining resistant property. SOLUTION: The rear surface of a transparent base material is processed with a mirror finishing, and its surface is coated with a fogging proof film which is formed by adding metal oxide particles such as fine colloidal silica having hydroxyl group on the surface and the mean diameter of which is 30-60 nm, to a matrix forming metal oxide compound composed of at least silica and zirconia, and nonionic surfactants. By synergistic effect with an uneven structure of the film surface, a water film is formed with excellent water retentivity for a long term.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fog mirror having a water film type anti-fog film formed on the surface of the mirror and having excellent transparency and stain resistance.

[0002]

2. Description of the Related Art Recently, a film having a photocatalytic function has been formed on the surface of a substrate in order to impart hydrophilicity, antifogging property or antifouling property to the substrate. For example, a plate-like member described in JP-A-5-253544, in which a photocatalyst fine powder mainly composed of anatase-type titania is partially exposed from the surface of a binder layer, JP-A-7-232080.
The photocatalyst fine particles described in JP-A No. JP-A-2003-15069 are titania, zinc oxide, strontium titanate, iron oxide, tungsten oxide, iron titanate, bismuth oxide, tin oxide, etc. , A multifunctional material having a photocatalytic function, which is a metal or oxide of zinc, iron, platinum, cobalt, nickel, or titanium oxide having an average photocatalytic crystal grain size of about 0.1 μm or less described in JP-A-9-59042. A transparent base material covered with a hydrophilic coating containing particles is known.

It has been known for a long time that a surface of a substrate is coated with a surfactant to make it hydrophilic, and the surfactant is water-soluble such as polyacrylic acid or polyvinyl alcohol. It is known, for example, from Japanese Patent Application Laid-Open No. 52-101680, to improve the durability of hydrophilicity by adding and blending an organic polymer.

Further, a method of immobilizing a hydrophilic polymer such as cellulose, glycols and glycerin on the surface and inside of a porous film made of a hydrophobic polymer through a film of a copolymer of polyvinyl alcohol and vinyl acetate. However, it is known, for example, from Japanese Examined Patent Publication No. 5-67330.

As a physical method, plasma treatment,
Hydrophilic treatment such as laser irradiation treatment further includes chemical methods such as a method of generating radicals on the surface and graft-polymerizing a polymerizable compound having a hydrophilic residue, and a method of binding the surface of an acid or a basic substance. A method of cleaving and changing to a hydrophilic residue is known.

[0006]

However, it is essential that the photocatalyst film is exposed to ultraviolet rays, and it is extremely difficult to exhibit hydrophilicity and antifogging property in a bathroom which is not exposed to ultraviolet rays. It is necessary to install a new light source so that the bathroom mirror is exposed to ultraviolet rays. Further, even if the surface is once rendered hydrophilic and antifogging by being exposed to ultraviolet rays, its performance can be maintained for a short time, and it will be lost after several hours. Therefore, it is necessary to frequently irradiate ultraviolet rays. further,
When the photocatalyst film is coated on the substrate, the titania that exhibits the photocatalytic function has a high refractive index film and thus has a high reflectance or is colored, and in particular, in the case of a mirror, the back surface side is subjected to a mirror surface treatment. A double image may occur, impairing the original function as a mirror, or impairing the design.

Further, the antifogging property due to physical treatment can maintain its effect only for a short period of time, and the polyethylene oxide organic polymer film has low water resistance and mechanical strength, so that it is practically used depending on the application. It's not enough.

Further, even in the method of immobilizing a coating film of cellulose or the like on the surface and inside of the porous film through a coating film of a copolymer of polyvinyl alcohol and vinyl acetate, the coating film is extremely soft and has a chemical property. It is also difficult to expect the desired durability, and the usage is limited.

As described above, all of these methods impart antifogging property only temporarily or for a relatively short period of time, and it is difficult to expect a sufficient durability of the antifogging effect. The cost was high and it was difficult to adopt in practical use.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and a metal oxide for forming a matrix which does not require ultraviolet rays and a hydroxyl group on the surface having a specific particle size are provided. The surface of the mirror is coated with an anti-fog film in which the metal oxide fine particles having are uniformly dispersed, and excellent water retention is imparted by a synergistic effect with the uneven structure of the film surface, which is excellent in transparency and stain resistance. An anti-fog mirror and a method for manufacturing the same are provided.

That is, the antifogging mirror of the present invention has an average particle diameter of 30 to 30 in the matrix-forming metal oxide composed of at least silica and zirconia on the surface of the mirror whose rear surface is mirror-finished. It is characterized in that the surface thereof having a thickness of 60 nm is covered with an anti-fog film formed by adding metal oxide fine particles having a hydroxyl group and a nonionic surfactant.

Further, in the anti-fog mirror of the present invention, the anti-fog film has a content of the metal oxide fine particles having hydroxyl groups on the surface of 40 to 6.
0% by weight, the content of metal oxide for matrix formation is 4
Further, the metal oxide for forming a matrix is composed of silica and zirconia, and the content ratio (in terms of weight%) of SiO ₂ : ZrO ₂ =
It is characterized by being 15:25 to 25:35.

Further, in the anti-fog mirror of the present invention, the raw material of silica as a matrix-forming component is represented by the general formula: R ₄ Si
An alkoxysilane represented by (R is an alkoxy group having 1 to 2 carbon atoms) is used.

Furthermore, the anti-fog mirror of the present invention is characterized in that the metal oxide fine particles having hydroxyl groups on the surface are colloidal silica and / or colloidal alumina.

Furthermore, the antifogging mirror of the present invention is characterized in that the antifogging film has a center line average roughness (Ra) of 1 to 50 nm and a haze value (haze value) of 1% or less. .

The method for producing an anti-fog mirror of the present invention is characterized by producing the anti-fog mirror by the following steps. (A) a step of producing a mirror by subjecting the back surface of a transparent substrate to mirror-finishing, and (b) metal oxide fine particles having a hydroxyl group on the surface having an average particle diameter of 30 to 60 nm, a metal oxide raw material for forming a matrix, A step of preparing a coating solution in which a nonionic surfactant and a solvent are uniformly mixed, (c) a step of coating the coating solution on the surface of a mirror to form a film, and (d) drying after forming the film to form a mirror Of coating the surface of the film with a water film type anti-fog film.

The anti-fog mirror according to claim 7, wherein the content of the nonionic surfactant in the coating liquid is 0.01 to 1% by weight.

Further, the method for producing an anti-fog mirror of the present invention is characterized in that the drying after the film formation is performed by heating and drying at a temperature of 100 ° C to 200 ° C.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The anti-fog mirror of the present invention has a mean particle diameter of at least a matrix-forming metal oxide composed of at least silica and zirconia on the surface of a mirror whose rear surface is mirror-finished. It is characterized in that the surface thereof having a thickness of 30 to 60 nm is covered with an antifogging film formed by adding metal oxide fine particles having a hydroxyl group and a nonionic surfactant.

As a main raw material of silica which is one of the metal oxide components for forming the matrix, metal alkoxides include silica alkoxides such as tetraethoxysilane, tetramethoxysilane, monomethyltriethoxysilane and monomethyltrioxide. Methoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, other tetraalkoxysilane compounds, other alkylalkoxysilane compounds and the like can be used, and in particular, the general formula: R4Si (R is an alkoxy group having 1 to 2 carbon atoms) It is more preferable to use a hydrolyzate of an alkoxysilane represented by the formula (1) since the hydrophilicity maintaining property becomes good.

As the raw material of ZrO ₂ , which is the other component as the matrix-forming metal oxide, Zr chloride or nitrate is used from the viewpoint of durability, particularly wear resistance, acid resistance and alkali resistance. Preferably, for example, as the Zr chloride, zirconium chloride, zirconium oxychloride (octahydrate), and chlorine-containing zirconium alkoxide Zr (OC _m H _{2m + 1} ) _x Cl
_y (m, x, y: integer, x + y = 4) etc. can be used,
As the nitrate of Zr, zirconium oxynitrate (dihydrate) or the like can be used, and in the case of alkoxides, zirconium butoxide, in the case of zirconia acetates,
Organometallic compounds such as zirconium acetylacetonate can be used.

The metal alkoxide raw material is hydrolyzed by mixing inorganic strong acid or organic strong acid with water as a catalyst.
A water-soluble hydrolyzate is obtained by polycondensation.
In the hydrolysis, the higher the SiO ₂ concentration in the reaction solution and the larger the amount of catalyst added, the shorter the hydrolysis progresses. However, what is hydrolyzed in a short time is Si
If the O ₂ concentration remains high, gelation tends to occur in a short time. Therefore, it is possible to stabilize the SiO ₂ concentration with water to about 5% by weight for one week or more.

The content ratio of silica and zirconia in the metal oxide film as the metal oxide for forming the matrix (in terms of weight%) is SiO ₂ : ZrO ₂ = 15: 25 to ₂
5:35 is preferable, and when the SiO ₂ content is less than 5% by weight, the mechanical strength and the acid resistance are lowered, and the ZrO ₂ content is 1
When it is less than 5% by weight, alkali resistance and hot water resistance are deteriorated, which is not preferable.

The type of the metal oxide fine particles having a hydroxyl group on the surface is not particularly limited, but it is necessary that the average particle diameter thereof is 30 to 60 nm, of which colloidal silica and / Alternatively, colloidal alumina is preferable. The colloidal silica is preferably water-soluble and stabilized with a monovalent cation such as sodium or ammonium. For example, commercially available products include Snowtex (manufactured by Nissan Kagaku), Ludox (manufactured by DuPont), and cataloid ( (Catalyst Kasei) and the like can be used. In the case of colloidal alumina, similarly to colloidal silica, it is stabilized with a monovalent cation such as sodium or ammonium. For example, as a commercially available product, use an alumina clear sol (manufactured by Kawaken Fine Chemicals) or the like. You can

The average particle diameter of the metal oxide fine particles is required to be in the range of 30 to 60 nm, but it is 30 nm.
When the amount is less than the above value, when contaminants such as shampoo, rinse and soapy water in the bathroom repeatedly adhere to the film surface, the water film forming ability of the film surface remarkably decreases and the pollution resistance deteriorates. on the other hand,
If it exceeds 60 nm, the haze value (haze value) of the film increases and the quality originally possessed by the mirror is impaired, which is not preferable, and a particle size in the range of 40 to 50 nm is more preferable.

The content of the metal oxide fine particles in the metal oxide film is preferably 40 to 60% by weight. If it is less than 40% by weight, the ability of forming a water film on the surface of the coating film is not sufficient, and the effect of the anti-fog mirror cannot be sufficiently exerted in actual use. Since the content ratio of the oxide is reduced, the adhesion to the surface of the base material and the mechanical and chemical durability are deteriorated. It is more preferably 40 to 50% by weight.

The nonion-on type surfactant added to the antifogging film is not particularly limited, but it is an ether type such as an alkyl ether type having a polyoxyethylene unit as a cumulative atomic group, an alkyl allyl ether type, or an alkyl type. Ester type, ester type such as sorbitan monoalkylamine type, condensation type with amine such as polyoxyethylene alkyl amide, condensation type with amide such as polyoxyethylene alkyl amide, polyoxypropylene such as polyoxyethylene polyoxypropylene Other examples include a condensation type with and a polyethyleneimine type. Further, as those having no cumulative atomic group, ester type such as sorbitan alkyl ester, fatty acid ester of various glycerin, pentaerythritol ester, ester of other polyhydric alcohol and fatty acid such as sucrose ester, fatty acid ethanolamide, Examples thereof include amide type compounds such as methylolamide, oxymethylethanolamide, and fatty acid ethanolamide derivatives, higher alcohols, glucosides, higher alkyl ethers, and the like.

The amount of the nonia-on type surfactant added is preferably 0.01 to 1% by weight as a weight% in the coating solution. If it is less than 0.01% by weight, the water-absorbing metal oxide fine particles aggregate and are not evenly dispersed in the metal oxide film, resulting in insufficient contamination resistance, while if it exceeds 1% by weight, chemical resistance such as chemical resistance is low. Sex decreases. The addition amount in the coating liquid is more preferably 0.05 to 0.5% by weight.

When preparing the above-mentioned coating liquid, water, a diluting solvent, glycols may be added to adjust the solid content concentration by a film forming method, and various additives such as a leveling agent may be added if necessary. it can. The total solid content concentration in the coating liquid is preferably 1 to 10% by weight in order to form a uniform coating film.

The diluent solvent is preferably an alcohol solvent, and specific examples thereof include methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, butylene glycol and pentylene. Glycol, hexylene glycol, further ethyl acetate,
Butyl acetate, esters such as amyl acetate, further cellulosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and solvents mixed with these, by adding methyl silicone such as dimethyl silicone as a leveling agent and a fluorine-based leveling agent in an appropriate amount. Is also good. The alcohol type or cellosolve type which is originally contained in the solution or a mixture thereof may be selected in consideration of the evaporation rate of the solution and the film viscosity.

The coating method is not particularly limited, but from the viewpoint of productivity, for example, a spin coating method or a dip coating method, a reverse coating method, a flexographic printing method, a screen printing method. , Bar coating method, other roll coating method, curtain coating method, further known means such as a nozzle coating method, a spray coating method can be adopted, by partial masking, of course, partial film formation, The film can be formed into any shape and pattern. It is preferable that the total concentration of solids in the coating liquid when applying and forming a film by these coating methods is about 1 to 10% by weight, and the viscosity of the coating liquid is about 2 to 6 centipoise.

Drying after coating is performed at 100 to 200 ° C.
At a relatively low temperature of 10 to 30 minutes, more preferably, the drying temperature is 160 to 180 ° C.
The drying time is about 20 minutes.

Although the thickness of the metal oxide film is not particularly limited, it is preferably in the range of 10 to 100 nm, and if it is less than 10 nm, there is no distortion of the image immediately after wetting with water and there is no fog. However, since the water absorption in the thickness direction of the film is small under high humidity in the bathroom, the thickness of the water film becomes uneven and the image is gradually distorted, which is not enough for the function of the mirror. Become. When the thickness is 100 nm or less, white turbidity due to diffused reflection of light can be prevented, and the appearance without problems such as interference colors and double images can be made to be the same as that of a general mirror.

Center line average roughness (Ra) of the antifogging film surface
Is preferably in the range of 1 to 50 nm, and 50 n
When it is m or more, the haze value (haze value) of the film is 1% or more. The center line average roughness Ra of the film surface is 15
More preferably, it is ˜30 nm.

The substrate used in the present invention is not particularly limited as long as it is transparent, and glass, plastic or the like can be used. For example, as a bathroom mirror, clear float glass having a thickness of about 5.0 mm is suitable, but it can be appropriately selected and used according to the size of the mirror. The environmental conditions of the bathroom are not particularly limited, but in order to more effectively exhibit the function of the antifogging mirror of the present invention, the room temperature is 10 to 40 ° C and the humidity is 70 to 9
An environment of 5% RH is preferable, and a bathroom anti-fog mirror whose substrate is a mirror is particularly preferable. The antifogging film is preferably formed on the surface of the mirror whose rear surface is mirror-finished, but in some cases, after forming the metal oxide film on the surface of the base material, the opposite surface There is no problem in giving a mirror surface to.

[0036]

The physical properties relating to the antifogging property are extremely highly dependent on the amount of hydroxyl groups on the film surface of the antifogging film, the water retention property from the surface to the inside, and the film surface shape capable of uniformly forming a water film. That is, if as much water as possible is absorbed or adsorbed and a uniform water film can be formed at this time, the antifogging effect can be maintained for a long time. According to the present invention, the antifogging film having an uneven surface formed on the mirror surface can maintain the antifogging property for a long time once it is wet with water because the film structure has a hydroxyl group on the surface which is a water-absorbing substance. A large amount of metal oxide fine particles are dispersed, and since they have hydroxyl groups on the surface, they easily adsorb water and also exhibit water retention. Due to this effect and the uneven surface, the adsorbed water forms a uniform water film, and water breakage hardly occurs. Furthermore, when the environment of use is a bathroom with high humidity, the water adsorbed on the membrane surface is hard to be desorbed, so once it is wet, it can exhibit anti-fogging property for a long time, and also double images. Looks very clear without. Further, since the surface of the film is covered with a uniform water film, stains such as oils are unlikely to adhere, and antifouling property is imparted.

[0037]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this embodiment. The physical properties of the bathroom anti-fog mirrors obtained in the present invention and the comparative examples were measured by the following measuring methods. [Evaluation of steam resistance]: After contact with boiling steam for 30 minutes, the antifogging property was evaluated. The pass / fail judgment was passed when the metal oxide film was not peeled off after wiping the contact site. [Evaluation of alkali resistance]: A cloth containing 5% -NaOH (aq) was brought into contact with the metal oxide film for 24 hours, and the appearance change after washing with water was evaluated. In addition, the pass / fail judgment was passed when the metal oxide film was not peeled off. [Evaluation of Contamination Resistance]: After conducting a test in which contaminants in the bathroom such as shampoo, rinse, soapy water, etc. were repeatedly attached to the surface of the metal oxide film, the ability to form a water film on the surface was evaluated. It should be noted that the pass / fail judgment was passed if the water film forming ability was not changed as compared with that before the contamination. [Evaluation of Film Formability]: A metal oxide film having hydrophilicity having a haze value of 1% or less was accepted. [Surface centerline average roughness (Ra) of film surface] 2.5 μm × at an arbitrary position of the film by using an atomic force microscope
It was determined by measuring a surface shape of 2.5 μm, and a surface center line average roughness (Ra) of 50 nm or less was accepted. [Film Thickness] Automatic Ellipsometer [Mizojiri Optical Co., Ltd. D
VA-FL3G]. The evaluation results of the following examples are shown in Table 1 and the evaluation results of the comparative examples are shown in Table 2. In the table, ◯ indicates pass, and x indicates fail.

Example 1 (1) Preparation of coating liquid Methanol-dispersed colloidal silica (trade name "MA-ST"
-L "manufactured by Nissan Chemical Co., Ltd., SiO ₂ content: 40.7% by weight, average particle size: 40 to 50 nm), ethyl silicate (reagent: manufactured by Kishida Chemical Co., Ltd.) as a silica sol for forming a matrix, and a hydrolytic acid catalyst. Zirconium oxychloride (reagent) which is a mixture of Echinene F-1 (manufactured by Kishida Chemical Co., Ltd., main component; ethanol: isopropyl alcohol = 9: 1), methyl propylene glycol (manufactured by Kishida Chemical Co., Ltd.) and ion exchange water Solvent (wt% is Echinen F
-1: Methyl propylene glycol: Ion-exchanged water = 6
It was diluted with 4: 28: 8) to prepare a solid content concentration of 3% by weight.

The coating solution was prepared by the following procedure. First, ethyl silicate and water-dispersed colloidal silica are mixed and stirred in a predetermined amount of a solvent so that silica matrix: colloidal silica = 25: 40% by weight in the metal oxide film, and uniformly dispersed to form a metal. After adding zirconium oxychloride corresponding to 35% by weight of zirconia in the oxide film, 0.04% by weight of Olfine ST-G (manufactured by Nisshin Chemical Co., Ltd.) corresponding to a nonionic surfactant is added, The mixture was stirred at room temperature to prepare a coating solution.

(2) Fabrication of anti-fog mirror for bathroom Mirror (thickness 5 m
m) is conveyed at a speed of 6 m / min, the surface of the mirror is coated with the coating liquid prepared above by a reverse roll coating method, and then the surface of the mirror is set to a temperature of 180 ° C. in a drying oven. By heating and drying for about 20 minutes, an anti-fog mirror having a mirror surface coated with a transparent metal oxide film having a film thickness of 70 to 80 nm was produced. The film composition (converted to weight%) of the formed metal oxide film is SiO ₂ : Zr.
O ₂ : colloidal silica = 25: 35: 40.
The obtained film had a surface center line average roughness (Ra) of 30.
The haze value was 0.4% in nm. As a result of evaluating the obtained anti-fog mirror, as shown in Table 1, it was excellent in all of alkali resistance, steam resistance, and stain resistance.

[0041]

[Table 1]

Example 2 Example 2 was repeated except that the amount of the nonionic surfactant added to the coating solution was 0.3% by weight. Evaluation result,
The surface center line average roughness (Ra) of the obtained film is 28 nm.
The haze value was 0.6%, and the other properties were excellent in alkali resistance, steam resistance, and stain resistance, as shown in Table 1.

Example 3 Example 1 was repeated except that the amount of the nonionic surfactant added to the coating solution was 1.0% by weight. Evaluation result,
The surface center line average roughness (Ra) of the obtained film is 33 nm.
The haze value was 0.8%, and the other properties were also excellent in alkali resistance, steam resistance, and stain resistance, as shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that no surfactant was added to the coating solution. As a result of evaluating the obtained anti-fog mirror, the surface center line average roughness (Ra) of the obtained film was 14 nm, and the haze value was 1.3%. As for other characteristics, as shown in Table 2, the alkali resistance, the steam resistance and the contamination resistance were acceptable, but the film forming property was poor.

[0045]

[Table 2]

Comparative Example 2 The content of Surfynol CT-324 (manufactured by Nisshin Chemical Co., Ltd.) corresponding to an anionic surfactant in the coating solution was 0.25.
The same procedure as in Example 1 was carried out except that the weight% was used. As a result of evaluating the obtained anti-fog mirror, as shown in Table 2, the stain resistance and the film forming property were acceptable, but the alkali resistance and the steam resistance were poor. The surface center line average surface roughness (R
a) was 12 nm.

Comparative Example 3 The procedure of Example 1 was repeated except that the surfactant was not added to the coating solution and 0.01% by weight of S030 (manufactured by GERMAN ADDITIVES) corresponding to the leveling agent was added. As a result of evaluating the obtained anti-fog mirror, as shown in Table 2, the film forming property was acceptable, but the alkali resistance, vapor resistance and stain resistance were poor.

Comparative Example 4 The procedure of Example 3 was repeated, except that a surfactant was not added to the coating solution and 0.04% by weight of S030 (manufactured by GERMAN ADDITIVES) corresponding to the leveling agent was added. As a result of evaluating the obtained anti-fog mirror, as shown in Table 2, the film forming property was acceptable, but it was inferior in stain resistance, alkali resistance and steam resistance.

Comparative Example 5 (1) Preparation of Coating Liquid As a raw material for colloidal silica, isopropyl alcohol-dispersed colloidal silica having a large particle size (trade name “IP
A-ST-ZL "manufactured by Nissan Chemical Industries, Ltd., the content of SiO _2: 3
0.4 wt%, average particle size: 70-100 nm),
Further, the same procedure as in Example 1 was carried out except that no surfactant was added to the coating solution. As a result of evaluating the obtained anti-fog mirror,
As shown in Table 2, the stain resistance was excellent, but the alkali resistance, film-forming property and vapor resistance were unacceptable.

Comparative Example 6 As a raw material for colloidal silica, isopropyl alcohol-dispersed colloidal silica having a large particle size (trade name "IP
A-ST-ZL "manufactured by Nissan Chemical Industries, Ltd., the content of SiO _2: 3
0.4 wt%, average particle size: 70-100 nm),
Furthermore, except that 1.5% by weight of Surfynol CT-324 which is an anionic surfactant was added to the coating solution,
The same procedure as in Example 3 was performed. As a result of evaluating the obtained anti-fog mirror, as shown in Table 2, the stain resistance and the film forming property were acceptable, but the alkali resistance and the steam resistance were poor.

Comparative Example 7 "Colloidal silica having a large particle size (trade name" IPA
-ST-ZL "manufactured by Nissan Kagaku Co., Ltd., wt%, average particle size: 70
Was carried out in the same manner as in Example 1 except that (.about.100 nm) was used. As a result of evaluating the obtained anti-fog mirror, as shown in Table 2, the vapor resistance and the alkali resistance were acceptable, but the film forming property was poor.

[0052]

Industrial Applicability According to the present invention, a metal oxide for forming a matrix is uniformly added with metal oxide fine particles having a hydroxyl group on the surface having an average particle diameter of 30 to 60 nm and a nonionic surfactant. An anti-fog mirror having a fog film formed on a mirror surface, the center line average roughness (R
Since a) is large, the water retention effect is high and the contamination resistance is excellent, and since the haze value is small and the haze value is small so that the transparency is not impaired, once water gets wet, a water film is formed on the surface of the film, Since it also imparts excellent water retention, it has an effect of being extremely excellent in antifogging properties when used, for example, in an environment of high relative humidity in a bathroom, and is particularly suitable as an antifogging mirror for bathrooms.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuo Moriguchi             1510 Oguchimachi, Matsusaka City, Mie Central Glass             Glass Research Institute Co., Ltd. F-term (reference) 3B111 AA01 AC01 AC03                 4G059 AA01 AC21 EA01 EA05 EA18                       EB07 FA03 FA05 FB06

Claims (9)

[Claims] 1. An average particle size of 30 to 60 in a matrix-forming metal oxide composed of at least silica and zirconia on the surface of a mirror whose rear surface is mirror-finished.
An anti-fog mirror characterized by being coated with an anti-fog film formed by adding metal oxide fine particles having a hydroxyl group and a nonionic surfactant to the surface having a thickness of nm. 2. The antifogging film is characterized in that the content of the metal oxide fine particles having a hydroxyl group on the surface is 40 to 60% by weight and the content of the metal oxide for forming a matrix is 60 to 40% by weight. The anti-fog mirror according to claim 1. 3. The metal oxide for forming a matrix comprises silica and zirconia, and the content ratio (in terms of weight%) is:
SiO ₂ : ZrO ₂ = 15: 25 to 25:35, The anti-fog mirror according to any one of claims 1 and 2, characterized in that: 4. A silica raw material used as a matrix-forming component is an alkoxysilane represented by the general formula: R ₄ Si (R is an alkoxy group having 1 to 2 carbon atoms). Anti-fog mirror described. 5. The anti-fog mirror according to any one of claims 1 to 4, wherein the metal oxide fine particles having hydroxyl groups on the surface are colloidal silica and / or colloidal alumina. 6. The antifogging film according to claim 1, wherein the center line average roughness (Ra) of the film surface is 1 to 50 nm and the haze value is 1% or less. Anti-fog mirror. 7. A method for producing an anti-fog mirror, which comprises producing the anti-fog mirror by the following steps. (A) a step of producing a mirror by subjecting the back surface of a transparent substrate to mirror-finishing, and (b) metal oxide fine particles having a hydroxyl group on the surface having an average particle diameter of 30 to 60 nm, a metal oxide raw material for forming a matrix, A step of preparing a coating solution in which a nonionic surfactant and a solvent are uniformly mixed, (c) a step of coating the coating solution on the surface of a mirror to form a film, and (d) drying after forming the film to form a mirror Of coating the surface of the film with a water film type anti-fog film. 8. The anti-fog mirror according to claim 7, wherein the content of the nonionic surfactant in the coating liquid is 0.01 to 1% by weight. 9. The method for producing an anti-fog mirror according to claim 7, wherein the drying after the film formation is performed by heating and drying at a temperature of 100 ° C. to 200 ° C.