JPH08117606A - Multifunctional material having photocatalytic function and its production - Google Patents

Abstract

PURPOSE: To provide a member hardly soiled and having deodorant and antimicrobial properties. CONSTITUTION: A layer having photocatalytic function is formed on the surface of a base material and smaller particles than gaps formed on the surface of the layer are filled into the gaps. Further at least one kind of a metal selected from Cu, Ag, Zn, Fe, Co, Ni, Pd, Pt is fixed on the surface. And the layer having the photocatalytic function is composed of crystalline TiO2 particles.

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 thin film formed on the surface thereof to have an antibacterial function or a deodorant function.

[0002]

2. Description of the Related Art Recently, it has been proposed to add an antibacterial function or a deodorant function by applying a photocatalyst on the surface of a base material. For example, Japanese Patent Publication No. 5-50294 and Japanese Patent Laid-Open No. 6-65012 are known as documents in which an antibacterial function is added by coating a photocatalyst on the surface of a substrate. Japanese Patent Publication No. 5-50294 discloses a sterilization reactor characterized by having a photo-sterilizable filler formed by immobilizing optical semiconductor fine particles on the surface of a base material. Further, in JP-A-6-65012, silver,
Disclosed is an antibacterial / antifungal ceramics characterized in that a substrate is coated with a titanium oxide film containing at least one metal ion selected from copper, zinc and platinum.

Japanese Patent Publication No. 46609/1992 discloses a document in which a deodorizing function is added by coating a photocatalyst on the surface of a substrate.
Japanese Patent Publication No. 4-46609 discloses a method for decomposing or modifying a malodorous substance contained in an odor in a vehicle interior air to purify an odor in the vehicle interior, which is a semiconductor solid photocatalyst in which a semiconductor carries a metal or a metal oxide. Purification of vehicle interior odor characterized by decomposing or modifying a malodorous substance contained in the odor in the air by photochemical reaction by irradiating the inside of the vehicle interior air to be purified with light A method is disclosed.

However, when a substrate having a photocatalyst coated on the surface of the substrate is used in an environment such as dirty water or an outer wall, stains are likely to adhere due to polymers, dust, fungi, etc. contained in the air or water. Depending on the type of dirt, the photocatalytic function may be deteriorated due to the adhesion of the dirt. Japanese Patent Publication No. 6-7905 is a conventional measure against the deterioration of the photocatalytic function due to the adhesion of dirt. In Japanese Patent Publication No. 6-7905, a photocatalyst layer made of a semiconductor, an ultraviolet lamp and a heating element provided to face the photocatalyst layer, and a blower are provided so that the entire photocatalyst layer is heated sequentially, or A deodorizing device using a photocatalyst in which a photocatalyst layer and a heating element move is disclosed. By heating up to around 400 ° C., stains due to polymers, dust and the like are removed, and the photocatalyst layer is regenerated.

[0005]

However, with such a method by regenerating the photocatalyst, it is practically difficult to do this for the members used for the equipment installed in the room. Therefore, rather than removing the stain after the stain adheres to the photocatalyst layer, the stain is less likely to adhere to the photocatalyst layer, or a more fundamental solution is desired so that the stain does not reduce the photocatalytic function.

In view of the above, the present invention provides a photocatalytic thin film structure in which a photocatalytic thin film is formed on the surface to impart an antibacterial function or a deodorant function, and dirt is less likely to adhere to the member, and the functional deterioration due to the dirt can be prevented. It is an object of the present invention to provide a member having antibacterial properties or deodorant properties, which is difficult to attach stains based on the obtained knowledge and can prevent functional deterioration due to stains.

[0007]

In the present invention, in order to solve the above problems, a layer having a photocatalytic function is formed on the surface of a base material, and the gaps formed on the surface of the layer are filled with particles smaller than the gaps. The gist is a multifunctional material having a photocatalytic function.

The details will be described below. Here, the material of the base material may be basically ceramics, ceramics, metal, glass, thermosetting resin, thermoplastic resin, or a composite thereof.
The shape of the base material may be any shape, such as a spherical shape or a simple shape such as a tile, a wall material, a plate material such as a floor material,
It may have a complicated shape such as sanitary ware, washbasin, or bathtub. The substrate surface may be a part of the substrate surface or the entire surface.

The layer having a photocatalytic function is a layer mainly composed of particles having a photocatalytic function. The particles having a photocatalytic function need to have a photoactivity that has a deodorizing function or an antibacterial function, that is, an amount that can generate active oxygen. For that purpose, it is necessary that the position of the conduction band is higher than the hydrogen generation potential and the upper end of the valence band is lower than the oxygen generation potential in the band model. Materials satisfying this condition include TiO2 and SrTiO
3, ZnO, SiC, GaP, CdS, CdSe, Mo
There are S3 etc. Further, when atomized, the position of the conduction band shifts upward, so if the layer can be composed of fine particles of about 1 to 10 nm, SnO2, WO3, Fe2O3, Bi2O3, etc. may also be able to generate active oxygen. Of these, TiO2, SrTiO3, ZnO, and
SnO2, WO3, Fe2O3, Bi2O3 are preferred. Hereinafter, these metal compounds will be referred to as photocatalysts. In order to have sufficient photoactivity, the photocatalyst particles have a particle size of 0.5 μm or less, preferably 0.1 μm or less.

Here, the step of forming a layer having a photocatalytic function on the surface of the base material is basically carried out by applying the starting material of the above-mentioned photocatalyst or a material which has been subjected to an appropriate treatment to the surface of the base material. As a starting material, a photocatalyst sol, a metal alkoxide, a metal sulfate, a metal chloride solution, an organic metal salt, or the like is used. For example, when a TiO2 sol is used, the isoelectric point of TiO2 is approximately pH 6.5, so that it is easy to apply uniformly if it is applied to the surface of the substrate using an aqueous solution dispersed with an acid or an alkali. At this time, when the substrate is a metal, alkali dispersion is preferable from the viewpoint of corrosion resistance. In the case of ceramics, tiles, ceramics, etc., either an acid or alkali dispersion may be used. Examples of the acid include nitric acid, sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, organic acids and the like. Examples of the alkali include ammonia and hydroxides containing an alkali metal or an alkaline earth metal, but ammonia is particularly preferable because no metal contaminant is generated after the heat treatment. In addition, an organic or phosphoric acid-based dispersant, a surface-active agent, a surface treatment agent, or the like may be further added to these dispersions. The average particle size of the photocatalytic sol is 0.05μ
m or less, preferably 0.01 μm or less. This is because the smaller the particle size, the higher the photoactivity of the photocatalyst. As a coating method on a substrate, these starting materials are spray-coated, roll-coated, dip-coated, spin-coated, CVD, electron beam evaporation,
There is a method of applying by sputtering or the like, any of which may be used, or any other method. However, spray coating, roll coating, and dip coating have the advantage that they do not require special equipment and can be coated at low cost, as compared with CVD, electron beam evaporation, sputtering, and the like. After coating, a layer having a photocatalytic function is formed by means such as drying and baking. The thickness of this layer is 0.4 μm
By setting the amount to be less than the above, the amount of particles filling the gap described below (the number of times of application) can be reduced as much as possible, and stain resistance (surface smoothness) and abrasion resistance can be satisfied, thus improving productivity and reducing costs. It can be reduced.

The layer having a photocatalytic function may have a glaze layer such as a glaze layer or a glass layer having a melting point lower than that of the base material in order to improve the adhesion to the base material. this is,
It is considered that the layer having the photocatalytic function is partially embedded in the glaze layer. The step of forming the glaze layer on the surface of the base material is performed by applying a glaze component having a softening temperature lower than that of the base material to the base material. The glaze component at this time does not necessarily have to match the composition of the glaze layer when the member is completed. Therefore, the application product of the glaze component at this time may be a suspension of the glaze composition in the form of particles, frit, lump, powder or the like, or may be a mixed solution of salts containing constituent metal components. The coating method includes a spray coating method, a roll coating method, a dip coating method and the like, and any of them may be used.

The step of heat treatment at a temperature at which the outermost surface of the photocatalyst layer is exposed and a part of the lower layer is embedded in the glaze layer is lower than the softening point of the base material, and the glaze layer is the glaze layer when the member is completed. The heat treatment is carried out at a temperature at which the composition changes and the material softens. Specifically, the heat treatment may be performed at a temperature 20 to 320 ° C. higher than the softening temperature of the glaze layer. By doing so, the photocatalyst particles are appropriately moved into the glaze layer, and the outermost surface of the photocatalyst layer is exposed and a part of the lower layer is embedded in the glaze layer. The glaze layer applied before the step of forming the photocatalyst layer on the glaze layer may be dried to evaporate water or the like. The drying method at this time includes a method of standing at room temperature, a method of heating with a base material, and the like.

Further, before performing the step of forming the photocatalyst layer on the glaze layer, the applied glaze layer is lower than the softening temperature of the base material, and the glaze layer has not changed to the composition of the glaze layer when the member is completed and softened. You may heat-process at the temperature which does.
According to this method, when the photocatalyst layer is formed on the glaze layer, the glaze layer becomes smoother in advance, so that a sufficient effect can be exhibited even with a small amount of photocatalyst particles applied.

The gaps formed on the surface of the thin film are specifically the gaps between particles in FIG. 1A, that is, open pores,
Both of the concave portions of the neck portion shown in FIG. It should be noted that the thin film is denser in terms of film strength and stain resistance,
Although excellent, in general, the temperature for forming a thin film becomes high, and the material of the base material is limited.According to the present application that fills the gap with particles in a later step, the porosity of the thin film before the addition of the gap particles is: It may be 10% or more. Further, a film having a porosity of 10% or more is excellent in deodorizing property, and therefore by adjusting the filling amount, a multi-functional material excellent in both antifouling property and deodorizing property can be provided.

Particles smaller than the gap filled in the gap are preferably made of an inorganic crystalline material, and more preferably have a photocatalytic activity, and therefore, TiO2 and SnO.
2, Fe2O3, ZnO, Bi2O3, WO3, SrT
An oxide semiconductor such as iO3 is preferable. The size of the particles smaller than the gap basically needs to be smaller than the average value of the pore diameters generated. Specifically, in terms of improving the surface smoothness and reducing the number of surface defects by decreasing the number of particles adhering to the surface of the particles having the photocatalytic function and the reduction of the voids, the stain resistance and the film strength can be improved. , 0.01μ
Small particles of less than m, preferably 0.008 μm or less are good. However, TiO2 thin film is anatase, 850 ℃
When heat-treated below and fixed on a substrate, the average pore diameter and the TiO particle diameter are generally the same when observed with an electron microscope, and therefore the particle diameter may be smaller than the TiO particle diameter. The starting material for the TiO2 thin film having photocatalytic activity is generally 0.1.
Since a raw material of 05 μm or less is used, it is preferably 0.05 μm or less.

Here, by setting the porosity of the surface of the layer having a photocatalytic function in which the gaps are filled with particles to be less than 20%, it becomes more difficult for dirt to attach. Further, the maximum width of the open pores is preferably 0.04 μm or less.
Here, the porosity refers to the open porosity of the surface of the base material, and the maximum width of the open pores means that adjacent particles among the particles having a photocatalytic function that form the surface of the base material as shown in FIG. Value of the gap distance between the two particles (average value + 3 x standard deviation)
That is.

When a layer having a photocatalytic function before filling the gaps with particles having a porosity of about 10% is used, the porosity is reduced to less than 10%, but the diameter of the buried pores is reduced. Since the size is such that particles with a crystal diameter of less than 0.01 μm can be entered, and it is large compared to the size of gas (several A), it does not affect the deodorant property and has a porosity of 10% or more that is prepared in advance. It is possible to maintain the deodorant properties equivalent to those of the TiO2 thin film.

Further, by making the formed layer having a photocatalytic function mainly crystalline photocatalyst particles, the stains do not adhere in a strong adhesion form like glass adheres, and even if the dirt adheres. It can be wiped off relatively easily. In addition, when used around water, there is an effect that it becomes difficult for algae to grow. Here, the crystalline photocatalyst particles are the photocatalyst particles peeled off from the member at 50 k.
The maximum peak of the crystal when powder X-ray diffraction was performed under the condition of V-300 mA (for example, in TiO 2 particles, 2θ = 25.3 ° for anatase and 2θ = 27.4 for rutile).
The photocatalyst particles are crystallized to the extent that (°) is detected.

As a method of filling the above gap with particles,
It is formed by applying a metal alkoxide, an organic metal salt, a sulfate or the like, coating, drying and heat treatment. For example,
The step of using the metal alkoxide is performed by applying a solution in which the metal alkoxide is mixed with an appropriate diluent and hydrochloric acid on the outermost surface of the photocatalyst layer and then performing a dry heat treatment. Here, as the suitable diluent, alcohols such as ethanol, propanol and methanol are preferable, but the diluent is not limited thereto. However, it is better not to include water as much as possible. This is because when water is contained, the hydrolysis of the metal alkoxide is explosively promoted, which contributes to the occurrence of cracks. Hydrochloric acid is added to prevent cracking during drying or heat treatment. The metal alkoxide coating method is usually flow
It is performed by coating, but is not limited thereto. Flow coating is preferably performed in dry air. When coating with normal air (atmosphere), water content in the air accelerates hydrolysis, making it difficult to control the film thickness. The coating may be applied once or several times. It is determined by the filling property of the photocatalyst layer before coating. After that, when left for several minutes in dry air, a film in which particles are filled in the gaps of the photocatalyst layer is formed. here,
It is preferable to use the same material as the layer before applying the filler particles and the filler particles, because the coefficient of thermal expansion may be the same and a film having excellent mechanical strength can be formed.

As a specific example, the one using a Ti alkoxide will be further described. In the step of further coating the surface of the photocatalyst layer with Ti alkoxide and performing heat treatment for drying, the coating amount of Ti alkoxide per time is TiO 2.
Converted to 2, 10 μg / cm 2 or more 100 μg / cm 2
It was set as follows. This is because if the amount is too small, the number of coatings must be increased, which is not efficient. On the contrary, if the amount is too large, the film thickness per coating becomes too thick and cracks occur during drying or heat treatment.

In the dry heat treatment step, the heat treatment temperature was set to 400 ° C. or higher and 800 ° C. or lower. Four
Amorphous TiO2 is below anatase type TiO2
Does not crystallize, and abrupt grain growth occurs above 800 ° C.
This is because the photoactivity is reduced. Further, the amount of hydrochloric acid with respect to the Ti alkoxide in the coating liquid was set to be 1% by weight or more and 10% by weight or less. If it is less than 1% by weight, the crack prevention effect is not sufficient, and if it exceeds 10% by weight, hydrochloric acid is usually 36%.
% Aqueous solution, a large amount of water enters and hydrolysis is promoted too much and cracks are generated. When the amount of hydrochloric acid is large, it is better to use a large amount of diluent. This is because the diluent suppresses hydrolysis. The ratio of hydrochloric acid (excluding water): diluent is preferably about 1: 100 to 1: 1000.

Further, a layer having a photocatalytic function is formed,
Cu, Ag, Zn, on top of the layer in which the voids formed on the surface of the layer are filled with particles smaller than the voids,
At least one metal selected from Fe, Co, Ni, Pd, and Pt may be fixed. With such a structure, since the metal having a high adsorptive site of the layer having a photocatalytic function occupies in advance, the alkali metal in the dust component, calcium, etc. adheres to this portion and loses the photocatalytic activity. There is no. Therefore, the antibacterial action of the photocatalyst is not easily impaired, and the stain due to the adhesion of fungi can be prevented. Furthermore, when Ag, Cu, or Zn is used as the above-mentioned metal, these metals themselves have antibacterial properties, so that stains due to adhesion of fungi can be effectively prevented. Further, the photocatalytic layer has improved photoactivity due to the electron-trapping effect of these metals. The size of the metal to be fixed is preferably large enough to occupy the highly adsorptive site of the photocatalyst layer in advance and small enough to maintain high activity. From this viewpoint, several nm
It is preferably about 10 nm.

As a method for fixing the above metal, a photoreduction method, a heat treatment method, a sputtering method, a CVD method or the like can be used, but a large-scale facility is not required and the method is relatively simple and robust. The photoreduction method is desirable because it can be fixed. The process using photoreduction is performed using Ag, Cu, Zn, Fe, Co, N.
This is performed by applying an aqueous solution containing at least one metal ion of i, Pd, and Pt and irradiating it with light containing ultraviolet rays.
The aqueous solution containing at least one metal ion selected from Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt includes copper acetate, silver nitrate, copper carbonate, copper sulfate, cuprous chloride, cupric chloride. , Chloroplatinic acid, palladium chloride, nickel chloride, zinc nitrate, cobalt chloride, ferrous chloride, ferric chloride and the like. The method of applying the metal salt aqueous solution may be basically any method, but the spray coating method or the dip coating method is convenient. Comparing the two, the amount of solution used can be small,
The spray coating method is more preferable because it can be applied uniformly, the film thickness can be easily controlled, and it can be applied when it is not desired to attach it to the back surface. The light source for irradiating the light including the ultraviolet light may be any light source capable of irradiating the light including the ultraviolet light, specifically, an ultraviolet lamp, a BL
Any of a B lamp, a xenon lamp, a mercury lamp and a fluorescent lamp may be used. In the method of irradiating light including ultraviolet rays, it is preferable to arrange the sample so that the light is irradiated perpendicularly to the irradiation surface. This is because the irradiation efficiency is the best. The irradiation time is preferably about 10 seconds to 10 minutes. If the irradiation time is too short, the above metal species will not sufficiently adhere to the highly adsorptive site of the photocatalyst layer, causing alkali metal in the dust component, calcium, etc. to adhere and cause loss of photocatalytic activity, and if the time is too long, This is because the metal species are excessively attached and it is difficult for light to reach the photocatalyst layer sufficiently, and the photocatalytic activity is reduced. The distance from the light source of the sample is preferably 1 cm to 30 cm. If the distance is too short, light will not be radiated to the entire sample surface with a substantially uniform illuminance, and the adhesion of the above metal species tends to vary.If the distance is too long, the illuminance of the emitted light will be inversely proportional to the square of the distance. Since it becomes smaller, it becomes difficult to firmly attach the metal species.

[0024]

In the present invention, a layer having a photocatalytic function is formed on the surface of the substrate, and the gaps formed on the surface of the layer are filled with particles smaller than the gaps.
Since the gaps formed on the surface of the thin film are filled with particles smaller than the gaps, the size of the gaps existing on the surface becomes small and the surface smoothness becomes good. , Dust, fungi, etc. are less likely to adhere.

[0025]

【Example】

(Example 1) An ammonia-deflocculating type suspension of a TiO2 sol having a crystal diameter of 0.01 µm was applied to a 15 cm square tile substrate by a spray coating method, and this was baked at 750 ° C to form an anatase type TiO2 thin film. did. The porosity of the TiO 2 thin film at this stage was 45%, and the crystal diameter of the TiO 2 particles was 0.02 μm. Then, SnO2 sols having different crystal diameters were applied thereon by a spray coating method and dried at 110 ° C. to obtain a sample. The obtained sample was evaluated for deodorizing property, abrasion resistance, and stain resistance. The deodorant property was evaluated by measuring R30 (L). R30 (L) is the removal rate after light irradiation, and specifically, the surface on which the anatase-type TiO2 thin film of the sample is formed in a 11 L glass container is the light source (BLB).
It can be obtained by arranging at a distance of 8 cm from a fluorescent lamp (4 W), injecting methyl mercaptan gas into the container so that the initial concentration is 3 ppm, and measuring the change in concentration when irradiated with light for 30 minutes.

The wear resistance was evaluated by performing sliding wear using a plastic eraser and comparing changes in appearance. The evaluation index is shown below. ◎: No change after 40 reciprocations ○: TiO2 was scratched by sliding 10 times or more and less than 40 times
Peeling of the layer Δ: Scratches occurred by sliding 5 times or more and less than 10 times, TiO2 layer was peeled ×: Scratching occurred by sliding less than 5 times, TiO2 layer was peeled. A line was drawn on the surface of the material with a thick black magic ink, and after drying, the ink was wiped off with ethanol, and the degree of contamination was evaluated. The evaluation index is shown. ◎: The mark disappears completely. ○: A slight trace remains. Δ: A gray-blue trace remains. X: A black mark remains. The results are shown in the figure.

FIG. 2 shows the stain resistance with respect to the added amount of SnO 2. Here, the added amount of SnO2 is represented by the ratio of the weight of SnO2 to the total weight of the amounts of TiO2 and SnO2. When SnO2 is added in an amount of 30% or more, the stains are hard to reach dramatically. It is understood that the reason is the following three points. First, the porosity was reduced to less than 20% by adding SnO2 in an amount of 30% or more (FIG. 3).
Secondly, the addition of SnO2 reduced the pores with large pore diameter. FIG. 4 shows the maximum width of open pores with respect to the added amount of SnO2, but when the added amount of SnO2 is 30% or more, it is as small as 0.04 μm. Thirdly, it is understood that the improvement of the surface roughness due to the addition of SnO2 also has an influence. FIG. 5 shows the deodorizing property and abrasion resistance with respect to the added amount of SnO2. SnO2 for deodorant
Even if the crystal diameter of the sol was changed from 0.0035 μm to 0.01 μm, there was almost no change and good results were shown.
When the amount of SnO2 is less than 50%, R30 is 8
A good result of 0% or more was shown. As compared with the relationship between the amount of added SnO2 and the porosity in FIG.
When the content is 0% or more and 50% or less, the porosity is less than 10%, but the deodorizing property is good. This tendency is different from the previously-applied relationship between the porosity and the deodorant property (FIG. 6) in the case where the particles for filling the gap are not added. The reason is considered as follows. That is, in this case, the porosity is 10%.
However, the pores of about 0.02 μm still remain as shown in FIG. 4, and the crystal diameter of the particles filling the gap is 0.0035 μm, which is larger than the size of the gas (several A). This is because, under this condition without grain growth, the phenomenon that the gas passage is closed does not occur.

Regarding the wear resistance, the addition amount of SnO2 is 30
%, The effect varied depending on the crystal size of SnO2 sol. That is, when particles of 0.008 μm or less were added, the result was improved to ⊚ or ◯, but at 0.01 μm, the effect of addition was not recognized. From the above experiment, the following was found. (1) When a TiO2 film is formed on a substrate and particles (SnO2 sol) smaller than the gap are added to the gap formed on the surface of the thin film, stains are less likely to adhere. (2) If the added amount of SnO2 is 30% by weight or more based on the total weight of TiO2 and SnO2, stains are less likely to attach,
Abrasion resistance is also improved. (3) When the added amount of SnO2 is 50% by weight or less with respect to the total weight of TiO2 and SnO2, the deodorant property can be kept good. (4) Porosity less than 20%, maximum open pore width 0.04
If the thickness is less than μm, stains are less likely to attach.

(Example 2) An anatase type TiO2 film was formed on the side portion of the urinals which was not exposed to light, and a field test was conducted for 2 weeks.
It was compared with the case where no O2 film was formed. As a result, yellow stains due to fungi and urinary stones adhered to both. However, while the stains of ordinary toilet bowls did not come off by rubbing, the yellow of the stains became almost inconspicuous when rubbed with anatase-type TiO2 film formed on the side surface. Since the side surface of the sana is not irradiated with light, this result is not due to the photocatalytic effect of the anatase-type TiO2 film, but rather to the fact that the crystalline anatase-type TiO2 film on which the stain is hard to adhere is formed on the surface. .

(Example 3) SiO2-Al2O3-Na / K20 frit was applied to the surface of a 15 cm square ceramic tile, and then TiO 2 having a crystal diameter of 0.01 μm was applied to the surface.
2 sol of ammonia peptization suspension was applied by spray coating method and baked at 750 ° C. for 2 hours.
O2 thin film thickness 0.2μm, 0.4μm, 0.8μm
3 types were prepared. The porosity of the TiO 2 thin film at this stage was 45%, and the crystal diameter of the TiO 2 particles was 0.02 μm. The cooled sample was further mixed with titanate tetraethoxide, 36% hydrochloric acid and ethanol at 10: 1: 400.
(Weight ratio) The mixed liquid was applied by a flow coating method using dry air as a carrier and dried. Coating amount is TiO2
Was set to 40 to 50 μg / cm 2. Then 1 at 500 ° C
Bake for 0 minutes. This Ti alkoxide coating step
Repeated 5 times. The obtained samples were evaluated for deodorant property, antibacterial property, abrasion resistance, and stain resistance.

Regarding antibacterial activity, Escherichia coli ( Escher
ichia coli W3110 strain). 0.15 ml (1 to 50000 CFU) of the bacterial solution was dropped on the outermost surface of the multifunctional material that had been sterilized with 70% ethanol in advance, and the bacterial solution was placed on a glass plate (100 × 100) and brought into close contact with the outermost surface of the substrate to obtain a sample. 3 white lights (3500 lux)
After irradiation for 0 minutes, the bacterial solution of the irradiated sample was wiped with sterile gauze and collected in 10 ml of physiological saline, and the survival rate of the bacteria was determined and used as an index for evaluation. The evaluation index is shown below. ++: Escherichia coli survival rate less than 10% ++: Escherichia coli survival rate 10% or more and less than 30% +: Escherichia coli survival rate 30% or more and less than 70% −: Escherichia coli survival rate 70% or more Deodorant under any of the above conditions The sex was 80% or more with R30 (L), and the antibacterial property was +++.

As for the stain resistance (FIG. 7) and abrasion resistance (FIG. 8), the number of times the Ti alkoxide was applied and TiO
2 Depends on film thickness. Increasing the number of times the Ti alkoxide was applied improved the stain resistance and abrasion resistance. Further, the thinner the TiO2 film thickness, the less the number of times the Ti alkoxide was applied, and the more the stain resistance and the abrasion resistance were improved. It is considered that one of the reasons for the above is that the porosity of the surface of the TiO2 layer is reduced by applying the Ti alkoxide. T in FIG.
The relationship between the porosity of the iO2 layer surface, the number of times the Ti alkoxide is applied, and the TiO2 film thickness is shown. The porosity of the TiO2 layer surface decreases as the Ti alkoxide coating number increases, and decreases as the TiO2 film thickness decreases with the same Ti alkoxide coating number. This relationship is related to the Ti alkoxide coating number and the TiO2 film thickness. It corresponds well to the relationship between dirt resistance and abrasion resistance. In particular, as to the stain resistance, as in the case of Example 1, when the porosity was less than 20%, all became ⊚.

Example 4 SiO2-Al2O3-Na / K20 frit was applied to the surface of a 15 cm square ceramic tile, and then TiO 2 having a crystal diameter of 0.01 μm was applied to the surface.
2 sol of ammonia peptization suspension was applied by a spray coating method and baked at 750 ° C. for 2 hours. At this stage, the TiO2 thin film has a film thickness of 0.4 μm and a porosity of 45.
%, And the crystal diameter of the TiO2 particles was 0.02 μm. A 10: 1: 400 (weight ratio) mixture of titanate tetraethoxide, 36% hydrochloric acid and ethanol was applied to the cooled sample by a flow coating method using dry air as a carrier, and dried. The coating amount is TiO2 40
˜50 μg / cm 2. Then, it was baked at 500 ° C. for 10 minutes. This Ti alkoxide coating step was repeated 3 times. Thereafter, a 1 wt% silver nitrate aqueous solution was further applied onto the sample, and photoreduction (a light source was a 20 watt BLB lamp, a distance from the light source to the sample was 10 cm, and an irradiation time was 30 seconds) to obtain a sample. Here, the amount of silver supported on the sample surface is 0.7.
The average particle size was about 40 nm.
The obtained sample was measured for antibacterial property and antibacterial property after long-term use.

The antibacterial property after long-term use was tested as follows. First, the surface of the obtained sample was thoroughly washed with ethanol or the like, and dried at 50 ° C. Next, bath water collected in a public bath was placed in a sterilized beaker, and the sample was immersed in the bath water and left for 1 month. Then, the sample was taken out and washed with ethanol or the like, and the outermost surface of the multifunctional material was sterilized with 70% ethanol. Then Escherichia
E. coli W3110 strain 0.15 ml (1-
50,000 CFU) was placed on a glass plate (100 × 100) and brought into close contact with the outermost surface of the base material to prepare a sample. White light (35
(00 lux) for 30 minutes, the bacterium solution of the radiated sample was wiped with sterile gauze and recovered in 10 ml of physiological saline, and the survival rate of the bacterium was determined and used as an index for evaluation. Example 3 is an evaluation index
It is similar to the antibacterial test of.

The sample used in Example 3 was also tested for comparison. As a result, regarding the initial antibacterial properties, both the sample prepared in this example and the sample prepared in Example 3 were +++, but there was a difference between them in the antibacterial properties one month later. . That is, the antibacterial property deteriorated to + in the sample prepared in Example 3, but +++ in the sample prepared in this example.
And showed the same value as the initial value. It is understood that this is because silver occupies the highly adsorptive site on the surface of the TiO2 layer, which prevents dust and the like from adhering to the highly adsorptive site during use.

[0036]

EFFECTS OF THE INVENTION Since a layer having a photocatalytic function is formed on the surface of a base material, and particles that are smaller than the gaps are filled in the physically generated gaps of the layer, the gaps existing on the surface more than the conventional photocatalytic thin film. Since the amount and size of the product are small and the surface smoothness is good, the film strength is improved while maintaining the deodorant property and the antibacterial property, and the macromolecules, dust, fungi, etc. that constitute the dirt component adhere. Can be hardened.

[Brief description of drawings]

1 (a) to 1 (c) are views for explaining the configuration of an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the amount of particles to be filled in the gap and the stain resistance.

FIG. 3 is a graph showing the relationship between the amount of particles filling the gap and the open porosity of the surface of the layer having a photocatalytic function.

FIG. 4 is a graph showing the relationship between the added amount of particles filling the gap and the maximum pore width on the surface of the layer having a photocatalytic function.

FIG. 5 is a graph showing the relationship between the amount of particles filled in the gap and the deodorant property and wear resistance.

FIG. 6 is a graph showing the relationship between the porosity of a layer having a photocatalytic function in which voids are not filled with particles and odor resistance and abrasion resistance.

FIG. 7 is a graph showing the relationship between the number of times particles are coated in the gap and the degree of stain resistance.

FIG. 8 is a graph showing the relationship between the number of coatings of particles filling gaps and wear resistance.

FIG. 9 is a graph showing the relationship between the number of coatings of particles filling gaps and the open porosity of the surface of a layer having a photocatalytic function.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location B01J 23/44 M 23/50 M 23/72 M 23/74 M (72) Inventor Keiichiro Norimoto 2-1, 1-1 Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka Prefecture Totoki Equipment Co., Ltd.

Claims (17)

[Claims] 1. A multifunctional material having a photocatalytic function, characterized in that a layer having a photocatalytic function is formed on the surface of a base material, and the voids formed on the surface of the layer are filled with particles smaller than the voids. . 2. A layer having a photocatalytic function is formed on the surface of a base material, and the voids formed on the surface of the layer are filled with particles smaller than the voids, and the porosity of the surface of the layer is less than 20%. A multifunctional material having a photocatalytic function, which is characterized in that 3. The multifunctional material having a photocatalytic function according to claim 2, wherein the maximum width of the open pores of the layer having a photocatalytic function is 0.04 μm or less. 4. The gap formed on the surface of the layer having a photocatalytic function is less than 0.01 μm, preferably 0.008 μm.
The multi-functional material having a photocatalytic function according to the first and second aspects, characterized in that it is filled with small particles of m or less. 5. A layer having a photocatalytic function is formed on the surface of a base material, and voids formed on the surface of the layer are filled with particles smaller than the voids, and further Cu, Ag, Z
A multifunctional material having a photocatalytic function, wherein at least one metal selected from n, Fe, Co, Ni, Pd, and Pt is fixed. 6. The multifunctional material having a photocatalytic function according to claim 1, wherein the layer having a photocatalytic function is formed on the surface of the base material via a glaze layer. 7. The multifunctional material having a photocatalytic function according to claim 1, wherein the layer having a photocatalytic function is mainly composed of crystalline photocatalytic particles. 8. A multi-function having a photocatalytic function, comprising: a step of forming a layer having a photocatalytic function on the surface of a base material; and a step of further applying a metal alkoxide or an organic metal salt to the surface and subjecting to dry heat treatment. Method of manufacturing wood. 9. A step of forming a layer having a photocatalytic function on the surface of a base material, a step of further applying a metal alkoxide or an organic metal salt to the surface and heat-drying, Ag, Cu,
A method for producing a multifunctional material having a photocatalytic function, which comprises a step of applying an aqueous solution containing at least one metal ion of Zn, Fe, Co, Ni, Pd, and Pt and performing photoreduction. 10. The method for producing a multifunctional material having a photocatalytic function according to claim 8, wherein the film thickness of the layer having a photocatalytic function is less than 0.4 μm. 11. A step of forming a glaze layer on the surface of a base material, a step of forming a layer having a photocatalytic function on the glaze layer, a top surface of the layer is exposed, and a part of the lower layer is the glaze layer. A step of heat treatment at a temperature such that it is embedded in
A method for producing a multifunctional material having a photocatalytic function, which further comprises a step of applying a metal alkoxide or an organic metal salt to the surface of the metal alkoxide or the organic metal salt and subjecting it to a dry heat treatment. 12. A step of forming a glaze layer on the surface of a base material, a step of forming a layer having a photocatalytic function on the glaze layer, the outermost surface of the layer is exposed, and a part of the lower layer is embedded in the glaze layer. Heat treatment at a temperature as described above,
A step of further applying a metal alkoxide or an organic metal salt on the surface thereof, followed by drying and heat treatment, Ag, Cu, Zn, Fe,
A method for producing a multifunctional material having a photocatalytic function, comprising the steps of applying an aqueous solution containing at least one metal ion of Co, Ni, Pd, and Pt and performing photoreduction. 13. The coating amount of Ti alkoxide per time in the step of coating Ti alkoxide on the surface having the photocatalytic function on the surface and performing heat treatment for drying is 10 μg / cm 2 or more and 100 μg / cm 2 or less in terms of TiO 2. The method for producing a multifunctional material having a photocatalytic function according to claim 8, 9, 11, or 12. 14. The heat treatment temperature is 400 ° C. or higher and 800 ° C. or lower in the step of coating Ti alkoxide on the surface of the layer having a photocatalytic function and performing a heat treatment for drying. 13. A method for producing a multifunctional material having a photocatalytic function according to 12 above. 15. The amount of hydrochloric acid with respect to the Ti alkoxide in the coating liquid is 1% by weight or more and 10% by weight or less in the step of coating the surface of the layer having a photocatalytic function with a Ti alkoxide and performing a dry heat treatment. The method for producing a multifunctional material having a photocatalytic function according to claim 8, 9, 11, or 12. 16. A step of forming a film having a photocatalytic function having a porosity of 10% or more, which is made of particles having a photocatalytic function, on the surface of a base material, and filling the voids formed on the surface of the film with particles smaller than the voids. A method for producing a multifunctional material having a photocatalytic function, comprising the steps of: 17. A step of forming a film having a photocatalytic function having a porosity of 10% or more, which is made of particles having a photocatalytic function, on the surface of a base material, and filling the voids formed on the surface of the film with particles smaller than the voids. Process, and then Cu, A
A method for producing a multifunctional material having a photocatalytic function, which comprises a step of fixing at least one metal selected from g, Zn, Fe, Co, Ni, Pd, and Pt.