JP2000126612A - Photocatalyst body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a photocatalyst on a substrate by short-time or low-temperature firing by using a specified inorganic material as the material of the substrate and forming a specified photocatalytically functional layer. SOLUTION: The surface of a fired glazed tile 3 consisting of a substrate 1 of an inorganic material such as glass, pottery, a tile or glaze and glaze 2 is spray-coated with a photocatalyst-containing material to form a photocatalytically functional layer 4. The photocatalyst-containing material uses a mixed sol of a solid content of a titanium dioxide sol containing metal ions carried on titanium dioxide, a silica sol and a potassium sol as the photocatalyst 7. The Seger value (SK) of the photocatalytically functional layer 4 is equal to or lower than that of the glaze 2 forming the surface side of the glazed tile 3. The particle diameter of the constituent materials of the layer 4 is <=1/100 of that of the constituent materials of the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifunctional material having a photocatalytic function for exhibiting an anti- (bactericidal) fungicidal function, a deodorizing function, and an antifouling function, which are excellent in treating wastewater and purifying harmful gases.

[0002]

2. Description of the Related Art In recent years, water pollution due to domestic wastewater and industrial wastewater, bad smell, and environmental pollution due to bacteria and fungi typified by MRSA in living and working spaces have become a social problem. Therefore, by irradiating light, organic compounds such as bacteria, fungi, and malodorous components cause adsorption or desorption of oxygen molecules, and titanium alkoxides and alcoholamines are substances that exhibit a function of promoting oxidative decomposition. Titania sol, TiO ₂ , ZnO, Sr
Photocatalysts such as particles of TiO ₃ and sol prepared by adjusting the particles with an aqueous solution are known.

As a device using this photocatalytic function, for example, as disclosed in Japanese Patent No. 2517874,
There is a photocatalyst body in which a titania sol is coated on a substrate, heated from room temperature to a final temperature of 600 ° C. to 700 ° C. and heated and baked to fix a photocatalyst. Conventionally, as shown in FIG. 5A, a photocatalyst material is fixed on a substrate surface using a substance serving as a binder, for example, a glaze or a glass frit, as shown in FIG. Had been immobilized.

At this time, the photocatalyst is fixed by melting glaze, glass frit, or the like, and as shown in FIG. 5 (b), from the surface toward the inside (base) and toward the inside (base). A concentration gradient is created in which the concentration of the photocatalyst decreases as the concentration increases. This is because the adhesion between adjacent photocatalysts on the surface of the substrate is fixed by heating, melting of glaze, glass frit, etc., and in order to make the concentration of photocatalyst uniform, it must be fired at a high temperature. I needed to. Therefore, firing time was required. Further, the material of the base material to be used had to be able to withstand the temperature of the high-temperature firing.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to fix a photocatalyst to a substrate by short-time or low-temperature sintering. It is an object of the present invention to provide a photocatalyst capable of selecting a fixing method according to the material of the material, and a multifunctional material having the photocatalyst.

[0006]

Means for Solving the Problems A photocatalyst comprising a base material and a photocatalyst functional layer fused to each other, wherein the base material is an inorganic material such as glass, porcelain, or tile ceramic. The photocatalytic function layer has a Zegel value (SK) equal to or lower than the Zegel value (SK) of the substrate surface, and the particle diameter of the raw material constituting the photocatalytic function layer constitutes the substrate. It is 1/100 or less of the particle diameter of the raw material.

The thickness of the photocatalyst functional layer is 100 μm or less, and the content of the photocatalyst on the fusion surface between the thin film surface and the substrate is uniform. The photocatalytic functional layer is made of TiO ₂ , Zn
A material having a photocatalytic function, such as O ₂ and SrTiO ₃ , containing at least 10% or more in solid content concentration, and containing Na ₂ O, K ₂ O,
Alkali metal oxides such as Li2O, CaO, alkaline earth metal oxides such as _{MgO, SiO 2, Al 2 O} 3, B 2 O3
Any one or more of such raw materials contains 80% or less. The photocatalytic function layer is formed on the surface of the substrate, and is fused and adhered by heating.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The inorganic substrate of the present invention may be any one made of an inorganic material such as glass, porcelain, tile, new ceramic, glaze, glass frit and the like. The photocatalyst particles of the present invention are particles that exhibit a photocatalytic function when irradiated with light having a wavelength having energy equal to or greater than the band gap, and include titanium oxide, zinc oxide, and tungsten oxide.
Known metal compound semiconductors such as iron oxide and strontium titanate can be used alone or in combination of two or more. In particular, titanium oxide which has a high photocatalytic function, is chemically stable, and is harmless is preferable.
Further, as a second component, V, Fe, Co, Ni, Cu, Zn, and R are provided inside and / or on the surface of the photocatalyst particles.
It is preferable to include at least one kind of metal and / or metal compound selected from the group consisting of u, Rh, Pd, Ag, Pt, and Au because they have a higher photocatalytic function. Examples of the metal compound include metal oxides, hydroxides, oxyhydroxides, sulfates, halides, nitrates, and metal ions. The content of the second component can be appropriately set depending on the substance. The photocatalyst particles containing the metal and / or metal compound are preferably titanium oxide.

Embodiment 1 will be described with reference to FIG. FIG.
1A is a configuration diagram of Example 1, and FIG. 1B is a diagram illustrating a concentration gradient of a photocatalyst. A photocatalyst-containing material was applied to the surface of the fired glazed tile 3 composed of the base material 1 and the glaze 2 by spraying to obtain a photocatalyst functional layer 4. The photocatalyst-containing material is a mixed sol of titanium oxide sol 0.1% solid, silica sol 0.3% and potassium sol 0.12%, in which metal ions are previously supported on titanium oxide by photocatalytic reduction power as photocatalyst 7. It was used.

The amount of the spray of the photocatalyst-containing material is 2
At 0 g / m ² , the photocatalytic function layer 4 contains about 20% of titanium oxide as a photocatalyst. Titanium sol solid content is 0.01
% To 0.3%, 0.01% to 1.0% of silica sol and 0.01% to 0.3% of potassium sol.
Further, if necessary, the alumina sol may be added in an amount of 0.01% to 0.0%.
You may add 01%. The glaze 2 constituting the surface side of the glazed tile 3 is formed with a glaze raw material having a particle size of 5 to 20 μm, and its Zegel value is 1: 0.3: 2 to R2O: R2O3: RO2. .

At this time, the Seegel value of the photocatalytic function layer 4 is:
R2O: R2O3: RO2 was 1: 0 to 0.1: 4 to 6, and the average particle size was 0.015 μm. By setting the average particle diameter of the photocatalyst function layer 4 to 0.015 μm and 1/100 or less of the particle diameter of the glaze raw material, the surface exposed area of the photocatalyst becomes large and works effectively, and the antibacterial, antifouling, and deodorizing effects are improved. Improved. For pre-loading of metal ions on titanium oxide, after mixing each sol and adjusting the concentration, copper as a metal salt is added to titanium oxide at a solid content of 3%, and ultraviolet rays (ultraviolet intensity of about 2 mW / cm ² ) was irradiated for 2 hours.
In the ultraviolet irradiation, the mixed sol solution was irradiated with stirring so that ultraviolet light was irradiated. The surface temperature of the glazed tile 3 sprayed with the photocatalyst-containing material was as high as 150 ° C. Therefore, when sprayed, moisture is instantaneously evaporated, and only the solid content is uniformly laminated on the tile surface to form a thin film of the photocatalyst-containing material having a thickness of about 0.5 μm.

Next, the glazed tile 3 having the thin film of the photocatalyst-containing material formed on the surface of the substrate 1 is placed in a rapid heating furnace continuously installed on a production line. Glazed tile 3
Is an ambient temperature of about 800 to 1000 ° C. (actually 850
° C), the rapid heating is performed for about 10 seconds under the heating element of the rapid heating furnace and for about 30 seconds during the time of passing through the entire rapid heating furnace, and the photocatalyst-containing material is calcined and fixed on the surface of the glazed tile 3. Then, the photocatalytic function layer 4 is formed.

The photocatalyst body 5 which is a tile having a photocatalytic function thus completed has a high decomposing function such as antibacterial property, antifouling property and deodorant property, and has hydrophilicity. Further, the strength (hardness) of the thin film of the photocatalyst-containing material formed on the surface of the glazed tile 3 was a hard film having a Mohs hardness of 4 or more, and was a strong film having excellent wear resistance and chemical resistance. Further, as shown in FIG. 1 (b), the photocatalyst functional layer 4 had a constant photocatalyst concentration from the surface fused with the glaze 2 to the surface. From this, it can be seen that the photocatalyst is uniformly dispersed in the photocatalyst functional layer 4 from the surface fused to the glaze 2 to the surface.

Embodiment 2 will be described with reference to FIG. FIG.
(A) is a configuration diagram of Example 2, and (b) is a diagram illustrating a concentration gradient of a photocatalyst. As shown in FIG.
A photocatalyst-containing material was applied by spraying to the surface of the unglazed tile 6 in which the base material 1 was fired to obtain a photocatalyst functional layer 4. The photocatalyst-containing material is a mixed sol of titanium oxide sol 0.1% solid, silica sol 0.3% and potassium sol 0.12%, in which metal ions are previously supported on titanium oxide by photocatalytic reduction power as photocatalyst 7. It was used.

The amount of the spray of the photocatalyst-containing material is 2
At 0 g / m ² , the photocatalytic function layer 4 contains about 20% of titanium oxide as a photocatalyst. Titanium sol solid content is 0.01
% To 0.3%, 0.01% to 1.0% of silica sol and 0.01% to 0.3% of potassium sol.
Further, if necessary, the alumina sol may be added in an amount of 0.01% to 0.0%.
You may add 01%. Base 1 on the surface of unglazed tile 6
A glass layer is formed by melting the base material of the above, and its Zegel value is R2O: R2O3: RO2: 1:
3:20. The particle size of the raw material of the unglazed tile 6 was 15 to 20 μm as an average particle size before granulation.

At this time, the Seegel value of the photocatalytic function layer 4 is R
1: 0.1: 4 to 6 for 2O: R2O3: RO2,
Its average particle size was 0.015 μm. For pre-loading of metal ions on titanium oxide, after mixing each sol and adjusting the concentration, copper as a metal salt is added to titanium oxide at a solid content of 3%, and ultraviolet rays (ultraviolet intensity of about 1 mW / cm 2). ) Was irradiated for 2 hours. At this time, the sol solution was irradiated with ultraviolet rays while being stirred. The unglazed tile 6 sprayed with the photocatalyst-containing material has a surface temperature of 15
Since the temperature is as high as 0 ° C., the moisture is instantaneously evaporated, and only the solid content is uniformly laminated on the tile surface to a thickness of about 0.5 μm.
Is formed.

Next, the unglazed tile 6 in which the thin film of the photocatalyst-containing material is formed on the surface of the substrate 1 is put into a heating furnace for re-baking which is continuously installed on a production line. The unglazed tile 6 has an ambient temperature of about 400 to 700 ° C. (actually 60 ° C.).
In this heating furnace for refiring (0 ° C.), heating is performed for about 10 to 20 minutes, and the photocatalyst-containing material is fired and fixed on the surface of the unglazed tile 6 to form the photocatalytic functional layer 4. 1 more than before
Photocatalyst 5 with good adhesion even when fired at a low temperature of 00 ° C. or more
Could be obtained.

The photocatalyst body 5 thus produced had a photocatalytic function, a high decomposing function such as antibacterial property, antifouling property and deodorant property, and further had hydrophilicity. The strength (hardness) of the thin film formed on the tile surface was a hard film having a Mohs hardness of 4 or more, and was a strong film having excellent wear resistance and chemical resistance. In addition, as shown in FIG. 2B, the photocatalyst functional layer 4 had a constant photocatalyst concentration from the surface fused with the substrate 1 to the surface. With this, the substrate 1
It can be seen that the photocatalyst 7 in the photocatalytic functional layer 4 is uniformly dispersed from the fusion surface to the surface. FIG.
As shown in the figure, the blending of the photocatalyst-containing material was applied to the glazed tile and the unglazed tile by changing the Zegel value, and the adhesion of the photocatalytic functional layer was confirmed. The photocatalytic functional layer 4 had good adhesion to the tile, and the preparation 4 had poor adhesion to the glazed tile and good adhesion to the unglazed tile.

Embodiment 3 will be described with reference to FIG. FIG.
(A) is a configuration diagram of Example 3, and (b) is a diagram illustrating a concentration gradient of a photocatalyst. A photocatalyst-containing material was applied to the surface of the fired glazed tile 3 composed of the base material 1 and the glaze 2 by spraying to obtain a photocatalyst functional layer 4. The photocatalyst-containing material is a mixed sol of titanium oxide sol in which metal ions are previously supported on titanium oxide by photocatalytic reduction power as photocatalyst 7, solid content 0.1%, silica sol 0.3%, and potassium silicate 0.12%. It was used.

The amount of the spray of the photocatalyst-containing material is 2
At 0 g / m ² , the photocatalytic function layer 4 contains about 20% of titanium oxide as a photocatalyst. Titanium sol solid content is 0.01
% To 0.3%, silica sol may be mixed at 0.01% to 1.0%, and potassium silicate may be mixed at 0.01% to 0.3%. Further, if necessary, the alumina sol may be added in an amount of 0.01% or more.
You may add 0.001%. The glaze 2 constituting the surface side of the glazed tile 3 is formed with a glaze raw material having a particle size of 5 to 20 μm, and its Zegel value is R 2 O: R 2 O 3: R
O2: 1: 0.3: 2-4.

At this time, the Seegel value of the photocatalytic function layer 4 is:
R2O: R2O3: RO2 was 1: 0 to 0.1: 4 to 6, and the average particle size was 0.015 μm. For pre-loading of metal ions on titanium oxide, after mixing each sol and adjusting the concentration, copper, which is a metal salt, is added to titanium oxide at a solid content of 3%, and ultraviolet rays (ultraviolet intensity of about 2 mW / c)
m ² ) for 2 hours. In the ultraviolet irradiation, the mixed sol solution was irradiated with stirring so that ultraviolet light was irradiated. The surface temperature of the glazed tile 3 sprayed with the photocatalyst-containing material was as high as 150 ° C. Therefore, when sprayed, moisture is instantaneously evaporated, and only the solid content is uniformly laminated on the tile surface to form a thin film of the photocatalyst-containing material having a thickness of about 0.5 μm.

Next, the glazed tile 3 having the thin film of the photocatalyst-containing material formed on the surface of the substrate 1 is placed in a rapid heating furnace continuously installed on a production line. Glazed tile 3
Is an ambient temperature of about 800 to 1000 ° C. (actually 850
° C), the rapid heating is performed for about 10 seconds under the heating element of the rapid heating furnace and for about 30 seconds during the time of passing through the entire rapid heating furnace, and the photocatalyst-containing material is calcined and fixed on the surface of the glazed tile 3. Then, the photocatalytic function layer 4 is formed.

The photocatalyst body 5, which is a tile having a photocatalytic function thus completed, has a high decomposing function such as antibacterial property, antifouling property and deodorant property, and has hydrophilicity. Further, the strength (hardness) of the thin film of the photocatalyst-containing material formed on the surface of the glazed tile 3 was a hard film having a Mohs hardness of 4 or more, and was a strong film having excellent wear resistance and chemical resistance. Further, as shown in FIG. 3B, the photocatalyst functional layer 4 had a constant photocatalyst concentration from the surface fused with the glaze 2 to the surface. From this, it can be seen that the photocatalyst is uniformly dispersed in the photocatalyst functional layer 4 from the surface fused to the glaze 2 to the surface.

Embodiment 4 will be described with reference to FIG. FIG.
(A) is a configuration diagram of Example 4, and (b) is a diagram illustrating a concentration gradient of a photocatalyst. As shown in FIG.
A photocatalyst-containing material was applied by spraying to the surface of the unglazed tile 6 in which the base material 1 was fired to obtain a photocatalyst functional layer 4. The photocatalyst-containing material includes, as the photocatalyst 7, a solid content of 0.1% of titanium oxide sol in which metal ions are previously supported on titanium oxide by photocatalytic reduction power, silica sol 0.3%, potassium silicate 0.06%, lithium silicate ( A mixed sol with 0.06% (containing sodium borate) was used.

The amount of the spray of the photocatalyst-containing material is 2
At 0 g / m ² , the photocatalytic function layer 4 contains about 20% of titanium oxide as a photocatalyst. Titanium sol solid content is 0.1
%, Silica sol 0.03%, potassium silicate 0.06%, and lithium silicate (containing sodium borate) 0.06%. Further, 0.01% to 0.001% of alumina sol may be added as needed. On the surface of the unglazed tile 6, a glass layer formed by melting the base material of the base material 1 was formed, and its Zegel value was R2O: R2O3: RO2, 1: 3: 20. The particle size of the raw material of the unglazed tile 6 was 15 to 20 μm as an average particle size before granulation.

At this time, the Seegel value of the photocatalytic function layer 4 is R
1: 0.1: 4 to 6 for 2O: R2O3: RO2,
Its average particle size was 0.015 μm. For pre-loading of metal ions on titanium oxide, after mixing each sol and adjusting the concentration, copper, which is a metal salt, is added at a solid content of 3% to titanium oxide, and ultraviolet rays (ultraviolet intensity of about 1 mW / cm ² )
For 2 hours. At this time, the sol solution was irradiated with ultraviolet rays while being stirred. The unglazed tile 6 sprayed with the photocatalyst-containing material has a surface temperature of 1
Because it is as high as 50 ° C, it instantaneously evaporates water,
Only solid content is uniformly laminated on the tile surface, about 0.5μ
An m thin film is formed.

Next, the unglazed tile 6 in which the thin film of the photocatalyst-containing material is formed on the surface of the substrate 1 is put into a heating furnace for re-baking, which is continuously installed on a production line. The unglazed tile 6 has an ambient temperature of about 400 to 700 ° C. (actually 60 ° C.).
In this heating furnace for refiring (0 ° C.), heating is performed for about 10 to 20 minutes, and the photocatalyst-containing material is fired and fixed on the surface of the unglazed tile 6 to form the photocatalytic functional layer 4. 1 more than before
Photocatalyst 5 with good adhesion even when fired at a low temperature of 00 ° C. or more
Could be obtained.

The photocatalyst body 5 thus prepared had a photocatalytic function, a high decomposing function such as antibacterial property, antifouling property, and deodorant property, and was further hydrophilic. The strength (hardness) of the thin film formed on the tile surface was a hard film having a Mohs hardness of 4 or more, and was a strong film having excellent wear resistance and chemical resistance. Further, as shown in FIG. 4B, the photocatalyst functional layer 4 had a constant photocatalyst concentration from the surface fused with the substrate 1 to the surface. With this, the substrate 1
It can be seen that the photocatalyst 7 in the photocatalytic functional layer 4 is uniformly dispersed from the fusion surface to the surface. These measurements can be carried out and confirmed by mapping titanium oxide by EPMA using an electron microscope and by analyzing the surface by XPS (X-ray photoelectron spectroscopy). Further, as shown in FIG. 6, the blending of the photocatalyst-containing material was applied to the glazed tile and the unglazed tile by changing the Zegel value, and the adhesion of the photocatalytic functional layer was confirmed. The photocatalytic function layer 4 had good adhesion to the tile and the unglazed tile, and the preparation 4 had poor adhesion to the glazed tile and good adhesion to the unglazed tile.

[0029]

According to the above constitution of the present invention, by selecting and blending a material composition which is expressed in Zegel which is lower than that of the base material or glaze, from the fused surface of the base material or glaze to the surface of the photocatalytic functional layer. Until the photocatalyst is evenly dispersed throughout,
Since it is immobilized, a high decomposition function and hydrophilicity can be obtained, and antibacterial, antifouling, and deodorizing functions can be improved.
In addition, a substrate having good adhesion between the base material or the glaze and the photocatalytic functional layer and high surface strength was obtained, and the durability was improved. Furthermore, low temperature firing and rapid heating firing became possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram and a photocatalyst concentration distribution diagram of a photocatalyst body according to Example 1.

FIG. 2 is a configuration diagram and a photocatalyst concentration distribution diagram of a photocatalyst body according to Example 2.

FIG. 3 is a configuration diagram and a photocatalyst concentration distribution diagram of a photocatalyst body according to Example 3.

FIG. 4 is a configuration diagram and a photocatalyst concentration distribution diagram of a photocatalyst body according to Example 4.

FIG. 5 is a configuration diagram and a photocatalyst concentration distribution diagram of a conventional photocatalyst body.

FIG. 6 is a view showing the adhesion of a photocatalytic functional layer.

[Explanation of symbols]

 1: Base material 2: Glaze 3: Glazed tile 4: Photocatalytic functional layer 5: Photocatalyst body 6: Unglazed tile 7: Photocatalyst

Claims (8)

[Claims] 1. A photocatalyst having a photocatalytic function in which photocatalytic particles are dispersed in an inorganic binder on an inorganic substrate, wherein the binder is melted and fixed to the inorganic substrate. Photocatalyst. 2. The photocatalyst according to claim 1, wherein the inorganic substrate is an inorganic material such as glass, porcelain, tile, new ceramic, glaze, glass frit and the like. 3. The photocatalyst functional layer according to claim 1, wherein said photocatalytic functional layer has a Zegel value (SK) equal to or lower than a Zegel value (SK) of said inorganic base material surface. The photocatalyst according to any one of the above. 4. The particle diameter of the raw material forming the photocatalytic functional layer is 1/1 of the particle diameter of the raw material forming the inorganic base material.
4. The method according to claim 1, wherein the value is not more than 00.
The photocatalyst according to any one of the above. 5. The photocatalyst according to claim 1, wherein the photocatalytic functional layer has a thickness of 100 μm or less. 6. The photocatalytic functional layer according to claim 1, wherein the content of the photocatalyst particles and the binder is uniform.
The photocatalyst according to any one of claims 1 to 5. 7. The photocatalytic function layer is made of TiO ₂ , ZnO ₂ ,
The photocatalyst according to any one of claims 1 to 6, wherein the photocatalyst contains a material having a photocatalytic function such as SrTiO ₃ at a solid content of at least 10% or more. 8. The photocatalytic function layer is composed of Na ₂ O, K ₂ O, L
alkali metal oxides i ₂ O, etc., CaO, alkaline earth metal oxides such as _{MgO, SiO 2, Al 2 O3} , B 2 to O ₃ any one or more of the ingredients, such as contains 80% or less The photocatalyst according to any one of claims 1 to 7, characterized in that: