JP3219076B2 - Method of forming laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to have excellent antifouling force, about a figure forming method of a laminate having a fouling removal photocatalyst film that exhibits durable surface layer.

[0002]

2. Description of the Related Art Titanium oxide is widely known as a material having excellent photocatalytic activity, and various photocatalytic reactions are known.
In recent years, it has been clarified that a titanium oxide thin film photoexcited by ultraviolet irradiation exhibits high hydrophilicity. Utilizing this property, the high antifouling power of the titanium oxide thin film was demonstrated, in which the dirt attached to the surface of the titanium oxide thin film can be easily removed by washing with water.

Conventionally, the following method has been used as a technique for producing a titanium oxide thin film having the above-described antifouling property and excellent durability on the surface of a substrate.

A titanium oxide sol obtained by dispersing titanium oxide fine particles in a solvent is applied to the surface of a substrate having a binder layer on the surface of the substrate and fired at a high temperature of about 700 ° C. or more, whereby the titanium oxide particles A uniform and detailed titanium oxide thin film can be produced on the surface without being buried inside the layer. The titanium oxide thin film thus produced exhibits high hydrophilicity under ultraviolet irradiation by the photocatalytic action of titanium oxide. Due to this effect, the titanium oxide thin film exhibits a high antifouling effect that organic dirt attached to the surface thereof can be easily removed by washing with water.

However, in these methods, spherical titanium oxide particles are immobilized on the surface of the base material, so that the surface has voids between the particles and surface roughness due to aggregation of the particles. For this reason, there has been a problem that it is not always easy to remove a dirt substance that has entered the surface irregularities.

In order to satisfy the surface hardness and abrasion resistance required for a ceramic product surface, a titanium oxide thin film is fixed to a base material such as ceramic at a high temperature of about 700 ° C. or higher and via a binder layer. There was a problem that it was necessary to make it.

[0007]

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 photocatalytic thin film on a substrate surface with a hardness as high as that of the prior art. While maintaining an increase in hydrophilicity and the ability to decompose organic substances due to ultraviolet irradiation, the heating temperature required for immobilization is lower, the binder layer is not required, and the adhesion-removing photocatalytic thin film having higher smoothness and its production are provided. It is to provide a method.

[0008]

As a result of repeated studies to solve the above-mentioned problems, a solution containing titanium alkoxide, which is a kind of metal alkoxide, was used as a film-forming material, and the solution was disposed on the surface of a base material. Titanium alkoxide is thermally decomposed and polymerized (dealcoholization reaction) by heat on the surface of the material or heat from low-temperature heat treatment of the base material, forming a titanium oxide thin film on the base material surface. While maintaining the increase in hydrophilicity and the decomposability against organic substances, the heating temperature required for immobilization is lower, no binder layer is required, and the smoothness is higher, so that dirt substances enter the surface irregularities. A method for forming a laminate having a high antifouling property and low stain resistance
Out we have seen, the present invention has been accomplished.

As the titanium alkoxide used in the present invention, any titanium alkoxide can be used as long as it is represented by the chemical formula of Ti- (OR) ₄ (where R represents an alkyl group). It is preferred to use propoxide.

The titanium alkoxide used in the present invention can be used after being diluted with a solvent. In this case, the solvent for the titanium alkoxide is an organic solvent having good compatibility with the titanium alkoxide and not hydrolyzing the titanium alkoxide. Can be used. Particularly, ethanol, isopropanol and isobutanol are preferred.

The concentration of the titanium alkoxide used in the present invention with respect to the solvent is not particularly limited, but may be 0.5 to 20.
% By weight is preferred.

As the film forming raw material used in the present invention, a material obtained by adding another metal alkoxide to a titanium alkoxide solution diluted in a solvent can be used. in this case,
It is desirable that the metal alkoxide species to be added have good compatibility with titanium alkoxide. Examples of such a metal alkoxide include tetraethyl orthosilicate, which is a kind of silicon alkoxide.

As a method for disposing a metal alkoxide on the surface of a substrate according to the present invention, any method may be used. This is particularly preferable because the surface shape of the substrate is not impaired.

The chemical vapor deposition method in which the vapor of the metal alkoxide is sprayed onto the surface of the base material is more specifically, the following method is used when titanium alkoxide is used as the metal alkoxide species. This is performed by spraying the vapor generated by vaporizing the solution containing titanium alkoxide directly or mixed with a carrier gas onto the base material. Further, as a simpler method, a method in which droplets of titanium alkoxide are sent into a carrier gas having a sufficiently high flow rate and vaporized by using a spraying apparatus and sprayed on a substrate can be used. In any method, it is preferable to heat the solution containing the titanium alkoxide to increase the vapor pressure so that the titanium alkoxide is quickly vaporized.

According to the above-mentioned method, after disposing a solution containing titanium alkoxide on the surface of a substrate by a method such as a chemical vapor deposition method, a method of forming a titanium oxide thin film on the surface of the substrate is as follows.
Either or both of the following methods (a) and (b) can be appropriately selected. By these methods,
An anatase-type titanium oxide thin film having high smoothness and hardness can be obtained without requiring a binder layer on a substrate. (A) Before disposing a solution containing a titanium alkoxide on a substrate surface by a method such as the chemical vapor deposition method or the like, the substrate surface is previously heated to a surface temperature of 50 to 600 ° C. A method in which part or all of titanium alkoxide disposed on the surface of a material is decomposed and polymerized by heat of the surface of the substrate to form a titanium oxide thin film on the surface of the substrate. (B) Titanium alkoxide provided on a surface of a substrate, which is subjected to a heat treatment in a temperature environment of 300 to 600 ° C. on a substrate provided with a solution containing a titanium alkoxide on the surface of the substrate by a method such as the chemical vapor deposition method or the like. A method of forming a titanium oxide thin film on the surface of a substrate by thermally decomposing and polymerizing part or all of the above.

In order to prepare a photocatalytic thin film having a stain-removing property, which comprises a semiconductor oxide such as titanium oxide and an insulator oxide, a solution in which an alkoxide of a metal species of the semiconductor oxide and the insulator oxide is mixed is used. By using the above-described film-forming method as a film-forming material, a thin film in which semiconductor oxide particles and insulator oxide are mixed can be formed on the surface of the base material (see FIG. 1). Since the semiconductor oxide and the insulator oxide are both exposed on the surface of the thin film formed in this manner, the photocatalytic properties of the semiconductor oxide are, of course, maintained. Target characteristics can be imparted to the surface. In addition, alkoxides of a metal species of a semiconductor oxide and alkoxides of a metal species of an insulator oxide are alternately provided on the surface, and a target oxide thin film is formed by heat treatment. It is also possible to form an oxide thin film in a layer on the substrate surface (FIG. 2).
reference). In this case, the number of oxide formations and the order of oxide formation are not limited. FIG. 2 shows an example of the thin film thus manufactured. As shown in FIG. 2, when an insulator oxide layer having good chemical adhesion is provided at the interface between the base material and the semiconductor oxide layer, the semiconductor oxide layer is provided more firmly on the base material. Becomes possible. Further, the diffusion of the element constituting the base material into the semiconductor oxide layer is suppressed by the insulator oxide layer, and various characteristics of the semiconductor oxide are maintained.

By providing a transition metal in the thin film of the present invention, it is possible to impart a greater decomposing power to organic substances to the thin film of the photocatalyst for removing stains. Copper, silver,
As an example of a method including a transition metal such as palladium, nickel, chromium, cobalt, and platinum, a solution containing ions of the transition metal is applied to the surface of the adhered dirt-removing photocatalytic thin film of the present invention, and ultraviolet irradiation is performed. An example is a method in which a transition metal ion is photoreduced and supported as a metal on the adhered and soil-removable photocatalytic thin film of the present invention.

As the substrate on which the titanium oxide thin film is formed in the present invention, any substrate may be used as long as its melting point is lower than the substrate heating temperature (300 to 600 ° C.) required for film formation. . In particular, ceramics such as glass, ceramics such as tiles, and oxides such as cement or concrete products are preferable.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, typical examples will be described more specifically with reference to examples of the present invention.

Example 1 First, in order to compare with the product of the present invention, a sample in which a titanium oxide thin film was formed on a tile using a conventional technique (hereinafter referred to as a comparative tile) and a sample of the present invention were prepared. A sample in which a titanium oxide thin film was formed on a tile using the method (hereinafter, referred to as an example tile) was prepared as follows. The tile of the comparative example is a tile obtained by spraying a commercially available titanium oxide sol containing titanium oxide at a ratio of 0.75% by weight on the tile surface and firing at about 850 ° C. At this time, the thickness of the titanium oxide thin film is about 0%. 0.5 μm.

The tiles used in the present invention were prepared by using a commercially available titanium tetraisopropoxide as a titanium alkoxide and diluting the solution with a commercially available isopropyl alcohol at a concentration of 10% by weight at a temperature of 20 ° C. with a surface temperature of 100 ° C. Titanium tetraisopropoxide was provided on the surface of the glazed tile by a method in which droplets of the solution were sent to dry air and vaporized on the glazed tile and sprayed onto the substrate. Subsequently, the glazed tile was subjected to a heat treatment at 500 ° C. for 30 minutes to produce an anatase-type titanium oxide thin film on the surface of the glazed tile.

The smoothness, hardness, hydrophilicity, and stain removability of the titanium oxide thin films on the surfaces of the obtained tiles of the comparative example and the example were evaluated. The smoothness of the titanium oxide thin film of the two types of sample tiles was measured by measuring the surface roughness using an atomic force microscope (SPM-9500) manufactured by Shimadzu Corporation. (Center line average roughness). The hardness of the titanium oxide thin film surface of the sample tile was evaluated by Mohs hardness. The hydrophilicity of the titanium oxide thin film surface of the sample tile was set in a dark place for 24 hours (described as dark in the following table) and the sample tile was set in a 1.2 mW / cm ² ultraviolet environment for 24 hours (hereinafter referred to as dark). In the table above)
Evaluation was made using the water contact angle of the sample tile. The stain removal property of the titanium oxide thin film surface of the sample tile is 1.2.
The color value of the sample tile surface was measured after the contaminated liquid was dropped at an interval of 1 drop / sec over a period of 5 hours from about 20 cm above the sample tile surface placed in an ultraviolet environment of mW / cm ² for 24 hours. The evaluation was made based on a color difference which was a comparison value with the color value (before the test was started). The contaminated liquid used here is 5
Wt% carbon black, 67.5 wt% yellow ocher, 22.5 wt% Kanto loam, 1.0 wt%
Is mixed with water to a concentration of 1 g / liter.

Table 1 shows the evaluation results of the comparative example tile and the example tile, and the heating conditions of the base material.

[0024]

[Table 1]

(2) Example 2 In the example tile, commercially available titanium tetraisopropoxide was used as the titanium alkoxide, and the concentration was 5% by weight.
A method in which a solution heated to 80 ° C. diluted with commercially available isopropyl alcohol is heated so that droplets of the solution are sent into dry air on a glazed tile having a surface temperature of 420 ° C., and vaporized, and sprayed onto a substrate. The titanium tetraisopropoxide was placed on the glazed tile surface. In the second embodiment, the heat treatment after disposing titanium tetraisopropoxide on the glazed tile is not performed in the second embodiment.

Using the same method as in Example 1, the smoothness, hardness, hydrophilicity, and stain removal property of the titanium oxide thin film on the surface of the comparative example tile and the example tile obtained in Example 1 were obtained. evaluated.

Table 2 shows the evaluation results of the comparative example tile and the example tile, and the heating conditions of the base material.

[0028]

[Table 2]

(3) Example 3 In the comparative example tile, titanium oxide and silica were 0.75 each.
Weight percent, a sol obtained by diluting a commercially available titanium oxide sol and silica sol with distilled water so as to be 0.095% by weight is sprayed on the glazed tile surface, and the tile is fired at about 850 ° C.
At this time, the thickness of the titanium oxide thin film is about 0.5 μm.
Example tiles were prepared by diluting commercially available titanium tetraisopropoxide and commercially available tetraethyl orthosilicate as titanium alkoxides with commercially available isopropyl alcohol such that their concentrations were 5% by weight and 1% by weight, respectively. The solution is sent to a glazed tile having a surface temperature of 130 ° C. by dropping the solution into dry air and spraying the vaporized product onto a substrate. Titanium tetraisopropoxide and tetraethyl orthosilicate are applied to the surface of the glazed tile. Arranged above. Then, apply the glazed tile to 50
Heat treatment was performed in a temperature environment of 0 ° C. to form a titanium oxide-silica thin film on the surface of the glazed tile.

Using the same method as in Example 1, the obtained comparative example tile and titanium oxide on the surface of the example tile were obtained.
The smoothness, hardness, hydrophilicity, and stain removal property of the silica thin film were evaluated.

Table 3 shows the evaluation results of the comparative example tile and the example tile, and the heating conditions of the base material.

[0032]

[Table 3]

The reason why the difference in surface roughness expressed by the center line average roughness between the comparative example tile and the example tile in Examples 1, 2 and 3 is presumed as follows. In the comparative example tile, titanium oxide sol was used as a film forming raw material, and titanium oxide particles having a relatively large particle diameter were immobilized on the surface of the base material. There is roughness. On the other hand, in the example tile, since titanium alkoxide and silicon alkoxide existing as individual molecules are used as a film forming raw material, particles of titanium oxide and silica having a large particle diameter are hardly formed on the surface, and voids between the particles are formed on the surface. Also, it is considered that the surface roughness caused by the aggregation of the particles is relatively smaller than those of the former. Further, the reason why the example tile is superior to the comparative example tile in Examples 1, 2 and 3 with respect to the adhesion dirt removal property is considered to be due to the high smoothness and hydrophilicity of the example tile.

Example 4 A copper acetate solution was applied to the surface of the example tile used in Example 1 and irradiated with ultraviolet rays, and copper ions were supported as metal copper using photoreduction. The weight of copper on the surface is about 1.0 μg / cm ² . The decomposing ability of the titanium oxide thin film having the thus-prepared copper particles on the surface thereof against organic substances was evaluated using the antibacterial activity against Escherichia coli.

The antibacterial activity of the evaluation is, E. coli (Escheri
chia coil w3110 strain). First, the surfaces of the above example tiles and blank tiles (normal tiles having no photocatalyst) are sterilized with 70% ethanol, and then 0.15 ml (1 to 5 ml) of Escherichia coli is applied to each tile surface.
× 104CFU) beat drop. A transparent glass plate was placed on the tile surface, and Escherichia coli was brought into close contact with the tile surface, and this was used as a sample. A pair of this sample was prepared for each tile. Next, one of the example tile and the blank tile was irradiated with a fluorescent lamp through a glass plate, and the other sample was placed in a light-shielded environment. And after a certain time,
The survival number of E. coli in the sample under the fluorescent lamp and the sample under the shade were measured, and the survival rate of E. coli in the example tile was calculated by using the ratio of the number of E. coli on the above example tile to the number of E. coli on the blank tile. And Further, the antibacterial rate (the rate at which Escherichia coli was killed or stopped growing) was determined from the survival rate.

The example tile exhibited an antibacterial rate of about 99% at one hour after the start of the irradiation under the fluorescent lamp irradiation and the light shielding environment.

[0037]

As described above, according to the method of the present invention, a titanium oxide thin film having high smoothness can be fixed on a substrate at a low temperature without a binder layer. In particular,
Since the titanium oxide thin film obtained by this method has a high surface smoothness, it is unlikely that dirt substances commonly found in daily life enter the unevenness of the surface and become difficult to remove, and have high hydrophilicity. By exhibiting excellent antifouling power. Further, the hardness of the film surface is large, and there is no problem in the durability of the film in daily use. Further, in the present invention, since a titanium oxide thin film can be formed on a substrate at a low temperature of 600 ° C. or lower, the amount of energy required for heat treatment can be reduced, and the emission of air pollutant gas such as carbon dioxide emitted from a combustion engine can be reduced. The feature is that the amount can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a thin film formed on a substrate surface in a state where a semiconductor oxide and an insulator oxide are mixed.

FIG. 2 is a diagram schematically showing a thin film formed on a substrate surface in a state where a semiconductor oxide and an insulator oxide are arranged in a layered manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor oxide particle 2 ... Insulator oxide particle 3, 6 ... Base material 4 ... Semiconductor oxide layer 5 ... Insulator oxide layer

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C03C 17/27 C03C 17/27 (72) Inventor Yoshimitsu Saeki 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Totoki Co., Ltd. (56) References JP-A-10-101374 (JP, A) JP-A-8-108075 (JP, A) JP-A-10-231146 (JP, A) JP-A-11-90237 (JP, A) Kaihei 11-290696 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (10)

(57) [Claims] 1. A attached to the surface of the substrate Chakuyogore removed photocatalyst thin film
A method for forming a laminate in which layers are stacked, the method comprising:
Before coating the substrate surface with the metal alkoxide,
Preheating so that the temperature of the substrate surface becomes 50 ° C or higher
Process and the process of coating the substrate surface with a metal alkoxide
And then at a temperature above preheating and below 600 ° C
Laminate characterized that you comprising heating such that
Formation method . 2. The method according to claim 1, wherein the metal alkoxide is titanium alcohol.
The laminate according to claim 1, characterized in that it is a Kishido
Formation method. 3. The method for forming a laminate according to claim 1, wherein
And the thin film has high smoothness and hardness,
The property that hydrophilicity is increased by photoexcitation and for organic substances
It has a decomposing power and is located in a 5 μm square area on the surface of the thin film.
And the center line average roughness is 2 nm or more and 15 nm or less.
Method of forming a laminate characterized and this with that smoothness. 4. The method for forming a laminate according to claim 3, wherein
Of the surface of the photocatalytic thin film after the photoexcitation
The contact angle of water is smaller than that of the photocatalytic thin film before the photoexcitation.
Smaller than the contact angle of water on the membrane surface in the range of 5 ° to 30 °
Form of laminate it characterized that you express fence made hydrophilic
Method . 5. A method for forming a laminate according to claim 3 or 4.
The method according to claim 1, wherein the adhesion-removing photocatalytic thin film comprises a photocatalyst.
Titanium oxide, tin oxide, which are semiconductor oxides that exhibit functions,
At least one method of forming the laminate characterized and this consists of oxides of zinc oxide. 6. A method for forming a laminate according to claim 5, wherein
Wherein the attached dirt removing photocatalytic thin film is
The product, the method of forming the laminate characterized and this constituted by blending insulator oxides. 7. A method for forming a laminate according to claim 5 or 6.
The method according to claim 1, wherein the adhesion-removing photocatalytic thin film comprises a transition metal.
Method of forming a genus or a transition metal oxide characterized and this constituted by blending a laminate. 8. The laminate according to claim 3, wherein
In the forming method, the adhered dirt removing photocatalytic thin film is
There are, you characterized that you photocatalyst particles are exposed laminated
How the body is formed . 9. The laminate according to claim 3, wherein
In the forming method, the surface of the laminate has a Mohs hardness of 4
Forming the laminate you characterized that you have a at which hardness than
How . 10. A laminate according to claim 3, wherein
In the method of forming, the base material of the laminate is glass,
For porcelain such as il, cement or concrete products, etc.
Product it characterized that it is a ceramic made of an oxide
A method for forming a layer body .