JP3309591B2 - Multifunctional material with photocatalytic function - Google Patents

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 performing functions such as a deodorizing function, an anti- (bactericidal) fungicidal function and an antifouling function.

[0002]

2. Description of the Related Art Irradiation of ultraviolet rays causes organic compounds such as malodorous components to be adsorbed or desorbed by oxygen molecules, and TiO ₂ , V ₂ are substances that exhibit a function of promoting decomposition (oxidation). O ₅ , ZnO, WO _{3 and the} like are known. In particular, TiO ₂ particles having an anatase crystal type have a high effect as a photocatalyst, and thus have conventionally been used as wall materials, tiles, glass (mirrors), circulating filtration devices or sanitary devices. Proposals have been made to form a photocatalytic layer on the surface of pottery or the like.

As a method for forming the photocatalyst layer, the following method has been conventionally used. Plastics, ceramics, on the surface of the substrate such as a resin, CVD method,
Direct T by sputtering, electron beam evaporation, etc.
A method for forming a photocatalyst layer composed of iO ₂ particles or the like. A method in which photocatalyst particles are kneaded with a binder and applied to the substrate surface by spray coating or the like, or dip-coated by dip coating, followed by heat treatment (JP-A-5-201747).

[0004]

When the CVD method, the sputtering method, the electron beam evaporation method, or the like is used, the equipment becomes large-scale and the yield is poor, so that the manufacturing cost increases.

On the other hand, in order for the photocatalyst particles such as TiO ₂ particles to exhibit the effect as a photocatalyst, it is necessary to irradiate the photocatalyst particles with ultraviolet rays and to contact the photocatalyst particles with a substance to be decomposed such as an odorous gas. Japanese Patent Application Laid-Open No. 5-201
If the photocatalyst particles were kneaded with a binder and applied to the substrate as in Japanese Patent No. 747, many photocatalyst particles would be buried in the binder layer and would not reach the ultraviolet rays or come into contact with the odorous gas. , Cannot exhibit a sufficient catalytic function.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention has the following means.

In a multifunctional material having a photocatalytic function in which a titanium oxide particle layer serving as a photocatalyst is held on a substrate surface via a binder layer, an upper layer of the titanium oxide particle layer is exposed from the binder layer so as to be in contact with the outside air. The lower layer portion of the titanium oxide particle layer is partially buried in the binder layer, and in the gap of the titanium oxide particles constituting the surface layer exposed from the binder layer in the titanium oxide particle layer, Particles having a smaller particle size than the gap are filled to sinter the titanium oxide particles, and the particles having a smaller particle size than the gap are any one of tin oxide, zinc oxide, and bismuth oxide. Particles having a smaller particle diameter than the titanium oxide particles are agglomerated at the neck between the titanium oxide particles, and the average particle diameter of the titanium oxide particles constituting the titanium oxide layer is 0. It was set to be less than 3 [mu] m. With this configuration, the upper layer of the photocatalyst layer is exposed, so that the catalytic function can be sufficiently exhibited. The lower layer of the photocatalyst layer is partially embedded in the binder layer, so that the photocatalyst layer is partially buried in the binder layer. Particles are less likely to peel from the substrate.

Here, the substrate may be any of tile, sanitary ware, ceramics such as glass, resin, metal, wood or a composite thereof.

The photocatalyst particles include TiO ₂ , Z
nO, SrTiO ₃ , Fe ₂ O ₃ , CdS, CdSe, W
O ₃ , FeTiO ₃ , GaP, GaAs, RuO ₂ , Mo
S ₃ , LaRhO ₃ , CdFeO ₃ , Bi ₂ O ₃ , MoS ₂ ,
In ₂ O ₃ , CdO, SnO _{2 and the} like can be mentioned, and any of these may be used. TiO ₂ , SrTi
O ₃ , Fe ₂ O ₃ , CdS, WO ₃ , MoS ₃ , Bi ₂ O ₃ ,
For MoS ₂ , In ₂ O ₃ , CdO, etc., the absolute value of the redox potential of the equivalent electronic band is larger than the absolute value of the redox potential of the conduction band, so that the oxidizing power is larger than the reducing power, and the decomposition of organic compounds is caused. Excellent deodorant, antifouling or antibacterial action. TiO ₂ , Fe ₂ O ₃ , and ZnO are advantageous in terms of raw material cost.

Further, the binder layer may be made of, for example, a glaze,
It is made of a thermoplastic material such as inorganic glass, thermoplastic resin, and solder. By configuring the binder layer with a thermoplastic material in this manner, a photocatalyst can be applied on the binder layer at a normal temperature by a simple and inexpensive method such as a spray coating method. And the photocatalyst can be firmly bonded, which is advantageous in the production cost.

Further, the multifunctional material having a photocatalytic function according to the present invention is constituted by laminating a photocatalyst layer made of photocatalyst particles on a sheet-like binder layer made of a thermoplastic material or embedding a part thereof. If such sheet-shaped multifunctional material is heated after pasting it on existing tiles, sanitary ware, building materials, etc., the existing tiles will be deodorized, stainproof, antibacterial, antifungal And other functions can be added.

The average particle size of the photocatalyst particles constituting the photocatalyst layer is preferably less than 0.3 μm in order to increase the specific surface area and enhance the photocatalytic activity.

Further, in order to enhance the abrasion resistance of the photocatalyst layer,
It is preferable that the photocatalyst particles constituting a portion of the photocatalyst layer exposed from the binder layer are bonded to each other.

The photocatalyst layer has a thickness of 0.1 μm to 0.9 μm.
μm is preferred. If the thickness is less than 0.1 μm, the photocatalyst particles are locally embedded in the binder layer, and a portion where the catalytic activity cannot be exerted on the surface of the multifunctional material occurs. I do. On the other hand, when the thickness exceeds 0.9 μm, the thickness varies greatly, and it becomes difficult to remove stains when stains adhere to the sample. Here, the thickness of the photocatalyst layer is a thickness including the portion from the outermost surface to the portion embedded in the lower layer of the binder layer, and the thickness of each unevenness.

Here, a design effect can be obtained by changing the thickness of the photocatalyst layer. That is, when the thickness is set to 0.2 μm or more and less than 0.4 μm, an iris pattern can be formed by the interference of light with respect to the photocatalyst layer film thickness portion. Alternatively, if only the combination thereof is desired, the portion that causes the light interference action is excluded from 0.1 μm or more and less than 0.2 μm or 0.4 μm.
The thickness of the photocatalyst layer should be less than 1 μm. Such a method can be applied to a wide range of tiles, sinks, bathtubs, large and small urinals, sinks, countertops, and the like.

As a method of bonding the photocatalyst particles constituting the portion of the photocatalyst layer exposed from the binder layer, for example, the gap between the photocatalyst particles is filled with particles having a smaller particle size than the gap. In the case where the photocatalyst particles are bonded to each other only by the photocatalyst particles, the only method is to adsorb or sinter the photocatalyst particles. However, when utilizing the sintering action between photocatalyst particles, sintering must be carried out at a considerably high temperature. On the other hand, in the case of adsorption, if the specific surface area of the photocatalyst particles is made very large and the packing property is not improved, the binding property will be high. In order to produce a multifunctional material having sufficient catalytic activity and abrasion resistance, for example, the method consumes only the active site adsorption amount of the photocatalyst particles. Further, if particles larger than the gap between the photocatalyst particles are used to strengthen the bond between the photocatalyst particles, not only a sufficient bonding force cannot be obtained, but also the photocatalyst particles exposed on the surface of the multifunctional material are partially covered. As a result, there is a portion on the surface of the multifunctional material where no catalytic activity can be exerted, and bacteria remain in that portion, so that the antibacterial property is significantly deteriorated. Here, the gap between the photocatalyst particles means the photocatalyst particles 3b and 3b as shown in FIG.
3b and both pores between the photocatalyst particles 3b, 3b as shown in FIG. 3 (b). Therefore, the particles 3c having a particle size smaller than the gap between the photocatalyst particles referred to here are particles smaller than any gap between the neck portion between the photocatalyst particles and the pores between the photocatalyst particles.

The material of the small particles to be filled in the gaps between the photocatalyst particles is not basically limited, but those having excellent adsorption power are preferable. An extremely weak material cannot achieve the purpose of binding the photocatalyst particles to each other, and a material having an extremely strong adsorption capability covers the active points on the surface of the photocatalyst particle rather than being inserted into a gap. This is because the probability increases. In view of this point, Sn, Ti, Ag, Cu, Zn, Fe, P
Metals or oxides such as t, Co, Pd, Ni and the like, and zeolite, activated carbon, clay and the like which have been conventionally used as an adsorption carrier are not preferred. Of the above metals or oxides, tin oxide is preferred in terms of having an appropriate adsorption capacity, and metals or oxides such as Ag and Cu are independently antibacterial in addition to binding photocatalyst particles to each other. ,
Since it has deodorant properties, it is preferable in that it has a function of assisting the action of the photocatalyst in applications utilizing this function, particularly when there is no light irradiation.

It is preferable that the average particle size of the particles filled in the gaps between the photocatalyst particles is 4/5 or less of the average particle size of the photocatalyst particles. Particles filling the gaps between the photocatalyst particles adhere to not only the gaps between the photocatalyst particles but also onto the photocatalyst particles to some extent in the current manufacturing method. The particle size of the particles filling the gap is 4 / the average particle size of the photocatalyst particles.
If it exceeds 5, the probability of adhering to the surface of the photocatalyst particles is higher than the gap between the photocatalyst particles, and the bonding strength between the photocatalyst particles decreases. Also, if the particles filling the gap are larger than the photocatalyst particles, they will partially cover the photocatalyst particles, and there will be a part on the surface of the multifunctional material that cannot exhibit catalytic activity, so that bacteria can stay in that part. Therefore, the antibacterial property may be significantly deteriorated.

The average particle diameter of the particles filled in the gaps between the photocatalyst particles is less than 0.008 μm.
It is preferable because the specific surface area is increased and an appropriate adsorption force can be obtained.

The amount of the particles filled in the gaps between the photocatalyst particles with respect to the photocatalyst particles is 10% or more and 6% or more in terms of molar ratio.
It is preferably 0% or less. When fixing the photocatalyst layer via a binder to the base material by heat treatment in a temperature range where sintering of the photocatalyst particles does not occur, if the amount of particles filling the gap is too small, the photocatalyst particles do not strongly bind to each other, On the other hand, if the amount of particles that fill the gap is too large, the amount of particles covering the photocatalyst particles will increase, and a portion that cannot exhibit catalytic activity on the surface of the multifunctional material will occur, and bacteria will be able to stay in that portion, Particularly, the above range is preferable because the antibacterial property is significantly deteriorated.

Further, as the substance constituting the particles to be filled in the gaps between the photocatalyst particles, a substance having a vapor pressure higher than the vapor pressure of the substance constituting the photocatalyst particles is selected and filled in the gap between the photocatalyst particles. Preferably, the particles are aggregated at the neck between the photocatalyst particles. This is because, in order to obtain a stronger bond between the photocatalyst particles and increase the peel strength of the photocatalyst layer, it is better not only to fill but also to sinter. Further, if such a substance having a high vapor pressure is selected as the particles for filling the gap, it functions as a sintering aid and can lower the sintering temperature. Examples of such a substance having a high vapor pressure include tin oxide, bismuth oxide, and zinc oxide, and tin oxide is preferable in terms of safety.

The thickness of the layer containing the particles filled in the gaps between the photocatalyst particles is preferably 0.1 μm or more. If the thickness of this layer is less than 0.1 μm, photocatalyst particles (and particles that fill gaps depending on the manufacturing method) are locally embedded in the binder layer, resulting in a portion where the catalytic activity cannot be exhibited on the surface of the multifunctional material. Since bacteria can be retained in the portion, the antibacterial property is particularly remarkably deteriorated.
Here, the thickness of the layer containing the particles to be filled in the gaps between the photocatalyst particles includes the portion from the outermost surface to the portion embedded in the lower layer of the binder, and is a uniform thickness of each of the irregularities.

Here, a design effect can be obtained by changing the thickness of the photocatalyst layer. That is, when the thickness is set to 0.2 μm or more and less than 0.4 μm, an iris pattern can be provided by the interference effect of light on the photocatalytic layer film thickness portion. Also, if there is no coloring by the particles that fill the gaps, if the appearance only needs to be the ground color of the base material, the pattern, or the combination thereof, the portion that causes the above-described light interference is excluded.
The thickness of the photocatalyst layer may be formed to be not less than m and less than 0.2 μm or not less than 0.4 μm and less than 1 μm. Such an approach is
It can be applied to a wide range of tiles, wash basins, bathtubs, large and small urinals, sinks, countertops, etc.

The depth of burying the photocatalyst particles constituting the lowermost layer of the photocatalyst layer in the binder layer is １ ／ of the particle size.
As described above, it is preferable that the photocatalyst particles are embedded in the binder layer by a thickness less than the thickness of the layer including the particles that fill the gap. By embedding the photocatalyst particles in the binder layer in a size of at least 1/2 of the particle size, the lowermost layer of the photocatalyst particle layer and the binder layer are firmly bonded to each other, and the thickness of the layer containing the particles that fills the gap with the photocatalyst particle If buried, the photocatalyst particles will not be exposed on the outermost surface, which will not be able to exhibit catalytic activity on the surface of the multifunctional material. Becomes significantly worse.

The base material can be used as a tile or a stone material used as a paving stone for artificial waterfalls or fountains of a water circulation system in parks and department stores. By utilizing a multifunctional material having a photocatalytic function for such an application, it is possible to decompose organic dirt deposited in water using artificial lighting or light including natural ultraviolet rays with circulation. In addition, it is possible to prevent breeding of bacteria, molds and the like, generation of algae, and accompanying water odor, thereby creating a cleaner environment.

The multifunctional material having a photocatalytic function according to the present invention is used as a device for preventing bacterial infection in hospitals, but can be used as an antifungal and antiviral device because it can decompose other organic substances.

Further, according to the method for producing a multifunctional material having a photocatalytic function according to the present invention, a binder layer made of a thermoplastic material is formed on a substrate made of ceramic, resin, metal or the like. A photocatalyst layer made of photocatalyst particles is formed thereon, and thereafter, the binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer,
Then it solidifies. Here, if the viscosity of the binder layer is too high, the binder layer and the photocatalyst particles do not bond sufficiently. Conversely, if the viscosity is too low, the photocatalyst particles are buried in the binder layer. The degree of softening of the binder layer is determined in consideration of these factors, since the antibacterial properties are significantly deteriorated due to the stagnation.

Another method for producing a multifunctional material having a photocatalytic function according to the present invention is to form a photocatalyst layer made of photocatalyst particles on a sheet-shaped binder layer made of a thermoplastic material, Is placed or adhered on a substrate made of ceramic, resin, metal or the like, and thereafter, the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then solidified. According to this method, existing tiles, sanitary ware, building materials, and the like can be later provided with functions such as deodorant properties, antifouling properties, antibacterial properties, and antifungal properties.

Another method for producing a multifunctional material having a photocatalytic function according to the present invention is directed to a photocatalyst in which the gap between the photocatalyst particles is filled with particles having a smaller particle size than the gap and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a function, comprising forming a binder layer made of a thermoplastic material on a substrate such as ceramic, resin or metal, and then forming a photocatalyst on the binder layer. A mixture of particles and the particles having the small particle size in a sol or precursor state is applied to form a photocatalyst layer.After that, the binder layer is softened, and a part of the lower layer of the photocatalyst layer becomes a binder layer. Buried and then solidified. According to this method, the photocatalyst layer is formed by applying a mixture in which the particles for filling the gap and the photocatalyst particles are mixed in a sol or a precursor state in advance, and thus the photocatalyst particles and the particles for filling the gap are mixed. Useful for controlling the ratio.

Another method for producing a multifunctional material having a photocatalytic function according to the present invention is directed to a photocatalyst in which the gap between the photocatalyst particles is filled with particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. It is a method of producing a multifunctional material having a function, this method, on a sheet-like binder layer made of a thermoplastic material, the photocatalyst particles and the small particles of the particle size were mixed in a sol or precursor state The mixture is applied to form a photocatalyst layer, and the sheet-like binder layer on which the photocatalyst layer is formed is placed or adhered on a base material such as ceramic, resin, or metal, and thereafter, the binder layer is softened. Then, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then solidified.

Another method for producing a multifunctional material having a photocatalytic function according to the present invention is directed to a photocatalyst in which the gap between the photocatalyst particles is filled with particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a function, comprising forming a binder layer made of a thermoplastic material on a substrate such as ceramic, resin or metal, and then forming a photocatalyst on the binder layer. A photocatalyst layer composed of particles is formed, and thereafter, the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. Is applied and heat-treated to immobilize the small-sized particles on the photocatalyst particles. This method can be carried out relatively easily when the particles filling the gaps are oxides, and can make a large amount of particles filling the gaps when a relatively porous photocatalytic layer is formed. .

Another method for producing a multifunctional material having a photocatalytic function according to the present invention is directed to a photocatalyst in which the gap between the photocatalyst particles is filled with particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a function, comprising forming a photocatalyst layer made of photocatalyst particles on a sheet-shaped binder layer made of a thermoplastic material, and then forming the photocatalyst layer on the sheet-shaped binder. The layer is placed or adhered on a substrate made of ceramic, resin or metal, and thereafter, the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. Then, a solution containing the small-sized particles is applied to the photocatalyst layer, and heat treatment is performed to fix the small-sized particles to the photocatalyst particles.

In another method for producing a multifunctional material having a photocatalytic function according to the present invention, a gap between photocatalyst particles is filled with metal particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a photocatalytic function, the method comprising forming a binder layer made of a thermoplastic material on a base material such as ceramic, resin or metal, and then forming a binder layer on the binder layer. A photocatalyst layer composed of photocatalyst particles is formed, and thereafter, the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. A solution having a photocatalytic function characterized in that a solution containing ions of metal particles is applied, and thereafter, light containing ultraviolet rays is irradiated to reduce the metal ions and immobilize them on the photocatalyst particles. Method of manufacturing capacity material. This method can be carried out relatively easily when the particles filling the gap are metal, and fix the metal in a very short time (several minutes).
Can be done with Further, a lamp used for ultraviolet irradiation may be any of an ultraviolet lamp, a BLB lamp, a xenon mercury lamp, and a fluorescent lamp.

In another method for producing a multifunctional material having a photocatalytic function according to the present invention, a gap between the photocatalyst particles is filled with metal particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a photocatalytic function, which method comprises forming a photocatalyst layer made of photocatalyst particles on a sheet-shaped binder layer made of a thermoplastic material, and then forming the photocatalyst layer on the sheet-like sheet. The binder layer is placed or adhered on a substrate made of ceramic, resin, metal, or the like, and thereafter, the binder layer is softened so that a part of the lower layer of the photocatalyst layer is embedded in the binder layer. After solidification, a solution containing ions of the metal particles having the small particle diameter is applied to the photocatalyst layer, and thereafter, the metal ions are reduced by irradiating light including ultraviolet rays and fixed to the photocatalyst particles. To.

In another method for producing a multifunctional material having a photocatalytic function according to the present invention, the gap between the photocatalyst particles is filled with metal particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a photocatalytic function, the method comprising forming a binder layer made of a thermoplastic material on a base material such as ceramic, resin or metal, and then forming a binder layer on the binder layer. A photocatalyst layer composed of photocatalyst particles is formed, a solution containing the ions of the metal particles having the small particle diameter is applied to the photocatalyst layer, and thereafter, the metal ions are reduced by irradiating light including ultraviolet rays and fixed to the photocatalyst particles. Then, the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. According to this method, the heat treatment step can be performed only once, so that the productivity is improved.

In another method for producing a multifunctional material having a photocatalytic function according to the present invention, a gap between the photocatalyst particles is filled with metal particles having a smaller particle size than the gap, and the photocatalyst particles are bonded to each other. A method for producing a multifunctional material having a photocatalytic function, the method comprising forming a photocatalyst layer made of photocatalyst particles on a sheet-like binder layer made of a thermoplastic material, A solution containing ions of metal particles is applied, and thereafter, light including ultraviolet rays is applied to reduce the metal ions to be fixed to the photocatalyst particles. Further, the sheet-like binder layer on which the photocatalyst layer is formed is made of ceramic, resin or metal. Or the like, and then the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified.

The photocatalyst particles are ZnO, and the metal particles filling the gaps between the photocatalyst particles are Ag or Ag ₂ O.
It is possible. Here, Ag or Ag ₂ O
The particles not only strengthen the bond between the ZnO particles that are photocatalysts, but also enhance the photocatalytic effect of ZnO, and also have antibacterial and deodorant effects themselves. In addition, by selecting ZnO as the photocatalyst, coloring due to Ag ions can be eliminated, and the design effect of the base color, pattern, or combination thereof can be improved.

Further, a solution containing a salt which forms a colorless or white salt which is insoluble with a metal ion filled in the gap between the photocatalyst particles is brought into contact with the photocatalyst layer, and thereafter, a light containing ultraviolet light is irradiated. May be irradiated. By doing so, the coloring due to the particles filling the gap can be eliminated without depending on the combination of ZnO and Ag or Ag ₂ O, and the background color of the base material can be eliminated. The design effect due to the patterns or their combination can be improved.

The photocatalyst particles are made of TiO _2, and the heat treatment temperature for softening the binder layer is 800 ° C.
The temperature may be higher than or equal to 1000 ° C. T above 800 ° C
Since the neck portion by initially sintered between iO ₂ grains are produced, the binding strength between TiO ₂ particles is improved, 1
If the temperature exceeds 000 ° C., the process shifts to the middle-stage sintering process, and TiO ₂
Since the volume shrinkage of the photocatalyst layer due to the solid phase sintering becomes remarkable, cracks are easily generated.

The photocatalyst particles are TiO _2, and the metal particles filling the gaps between the photocatalyst particles are Ag,
The solution containing salts that form an insoluble and colorless or white salt with the metal ions may be used as an aqueous solution of a halide such as KI, KCl, and FeCl ₃ . Since Ag forms an insoluble and colorless or white salt such as AgI and AgCl with an alkali halide, it is possible to improve the design of the base color, pattern, or the combination thereof by combining them.

Further, the binder layer is selected to have a softening temperature lower than the softening temperature of the base material. The softening temperature of the binder layer is more than 20 ° C. and less than 320 ° C., preferably 40 ° C. or more and 300 ° C. or less. The heat treatment is performed at an ambient temperature in the range of not more than ℃ and lower than the softening temperature of the substrate. If the heat treatment temperature is lower than the temperature 20 ° C. higher than the softening temperature of the binder layer, the viscosity of the binder layer is too high, so that the binder layer and the photocatalyst particles are not sufficiently bonded, and conversely, the temperature is 320 ° C. lower than the softening temperature of the binder layer. If the heat treatment temperature is higher than ℃ higher temperature, the viscosity of the binder layer is too low and the photocatalyst particles will be buried in the binder layer, and if it occurs locally, bacteria will stay there, resulting in a decrease in antibacterial properties It depends.

When a dispersing step is provided as a step prior to the step of applying the photocatalyst particles on the binder layer, a dispersant for dispersing the sol or precursor to be the photocatalyst particles in the dispersion step in the solution. It is preferable to use only components that vaporize at a temperature lower than the heat treatment temperature for softening the binder layer. In the prior art,
Had no deodorant below 320 ° C., the dispersion step the dispersion agent is sufficiently vaporized attached to TiO ₂ particle surface in, for remaining in the not evaporate sufficiently TiO ₂ particle surface to the substrate top surface Because the photocatalytic function became insufficient. As the dispersant that evaporates at a low temperature, an organic dispersant having a molecular weight of 10,000 or less and a phosphoric acid-based dispersant are preferable.

When the specific gravity of the photocatalyst particles is δt and the specific gravity of the binder layer is δb, 0 ≦ δt−δb ≦ 3.
It is preferably 0. If the specific gravity difference is too small, the photocatalyst particles are not sufficiently embedded in the binder layer, and the binder layer and the photocatalyst particles are not sufficiently bonded.If the specific gravity difference is too large, the photocatalyst particles are buried in the binder layer. If it occurs locally, bacteria stay on the bottom and the antibacterial property is reduced. As an application method of this method, δt
Even when −δb> 3.0 is required, a second binder layer satisfying 0 ≦ δt−δb ≦ 3.0 may be interposed between the binder layer and the photocatalyst particles. Also δt
When −δb <0, pressurizing during the heat treatment has the same effect as increasing the specific gravity difference Δt−δb. Therefore, H
By IP processing and hot press processing, 0 ≦ δt−δb ≦
The same effect as in the case of 3.0 can be obtained.

[0044]

The photocatalyst particles constituting the lower layer on the binder layer side of the photocatalyst particles constituting the photocatalyst layer are partially retained in the binder layer, and the photocatalyst constituting the surface layer of the photocatalyst layer which is in contact with the outside air. Since the particles are bonded to each other with the surface substantially exposed to the outside, the photocatalytic effect is sufficiently exhibited.

[0045]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a view for explaining a method for producing a multifunctional material having a photocatalytic function according to the present invention, and FIG.
FIG. 3D is an enlarged view of a main part. In the present invention, first, as shown in FIG. As the base material 1, ceramic, resin, metal, glass, wood or the like can be considered.

Then, a binder layer 2 is formed on the surface of the substrate 1 as shown in FIG. The binder layer 2 is selected from a material whose softening temperature is lower than the softening temperature of the substrate 1. For example, when the substrate 1 is a tile, an enamel or a ceramic, the glaze layer or the printed layer can be used as the binder layer 2 as it is.

Next, a photocatalyst layer 3 made of photocatalyst particles such as TiO ₂ particles is formed on the binder layer 2 as shown in FIG. At this time, the photocatalyst layer 3 only needs to be mounted on the binder layer 2 with such a bonding force that the photocatalyst layer 3 does not fall off the binder layer 2 in the subsequent baking.

Alternatively, a binder layer 2
Before forming a photocatalyst layer, a photocatalyst layer 3 is formed on the binder layer 2 as shown in FIG.
May be placed on the substrate 1.

Thereafter, heat treatment is performed at an ambient temperature higher than the softening temperature of the binder layer 2 and higher than 20 ° C. and lower than 320 ° C. and lower than the softening temperature of the base material 1 to obtain the heat treatment shown in FIG. As shown in FIG. 2, a part of the photocatalyst particles 3 a constituting the lower layer of the photocatalyst layer 3 on the binder layer side is settled in the molten binder layer and the binder layer is solidified, so that the part is in the binder layer. Buried in and firmly held. Further, as shown in FIG. 3A, a part of the photocatalyst particles 3b constituting the surface layer of the photocatalyst layer 3 which is in contact with the outside air is bonded to each other by intermolecular force and sintering by sintering. Are separated from each other as shown in FIG. That is, the surface of the photocatalyst particles 3b is exposed to the outside substantially in the surface layer.

Here, the reason why the heat treatment temperature is set higher than the softening temperature of the binder layer 2 in the range of more than 20 ° C. and less than 320 ° C. is that if the temperature is lower than 20 ° C., it takes time for the softening of the binder layer and the photocatalyst becomes harder. On the other hand, when the temperature exceeds 320 ° C., the photocatalyst particles are buried in the binder layer due to the rapid melting of the binder layer, and irregularities are generated. Desirably, the temperature is 40 ° C. or more and 300 ° C. or less.

When the specific gravity of the photocatalyst particles is δt and the specific gravity of the binder layer 2 is δb, 0 ≦ δt−δb ≦ 3.0.
Preferably, the relationship of 0.5 ≦ δt−δb ≦ 2.0 is satisfied. This is because, when the difference in specific gravity between the photocatalyst particles and the binder layer is too small, when the binder layer is melted, the vertical movement speed of the photocatalyst particles in the binder layer becomes slow, and the photocatalyst particles are easily separated after firing, If the difference in specific gravity between the photocatalyst particles and the binder layer is too large, the moving speed of the photocatalyst particles in the vertical direction increases, and most of the photocatalyst particles may be buried in the binder layer. The gap between the photocatalyst particles constituting the portion exposed from the binder layer 2, specifically, the photocatalyst particles 3 shown in FIG.
b, or the photocatalyst particles 3b shown in FIG.
Between particles 3c (Sn,
Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, N
(i.e., a metal or an oxide such as i) may be filled to bond the photocatalyst particles 3b to each other.

Specific examples will be described below. (Reference Example 1) SiO ₂ —Al ₂ was coated on the surface of a ceramic tile substrate of 150 squares.
After forming a binder layer composed of an O ₃ —Na / K ₂ O frit by a spray coating method and drying, a 15%
A TiO ₂ sol aqueous solution is applied by a spray coating method to form a TiO ₂ layer having a thickness of 0.8 μm, and then the base material on which the binder layer and the TiO ₂ layer are laminated is heated at an ambient temperature using a roller hearth kiln. Was heated and calcined in different examples, and then cooled and solidified to obtain a multifunctional material. Here, the TiO ₂ sol aqueous solution is, for example, an anatase type TiO ₂ having a crystallite diameter of about 0.007 to 0.2 μm obtained by hydrolyzing TiCl ₄ in an autoclave under hydrothermal conditions in the range of 100 to 200 ° C. In a sol, a few% of the solution is added to an acidic aqueous solution such as nitric acid or hydrochloric acid or a basic aqueous solution such as ammonia.
To improve the dispersibility by adding an organic acid salt of triethanolamine and trimethylolamine, pentaerythritol, trimethylolpropane, etc. in a range of 0.5% or less as a surface treatment agent. It has been added. Incidentally, the particle size of the TiO ₂ sol by the image processing of SEM observation, the crystallite size was calculated from the integration width of the powder X-ray diffraction <br/>. In addition, although the coating method was performed by the spray coating method, it is expected that similar results can be obtained by the dip coating method and the spin coating method. The obtained multifunctional material was evaluated for antibacterial properties and abrasion resistance. For antibacterial activity, Escherichia coli W
3110 strain). Bacterial solution 0.15 m on the outermost surface of multifunctional material previously sterilized with 70% ethanol
l (1-5 × 10 4 CFU) was dropped, and a glass plate (10
(× 10 cm) and adhered to the outermost surface of the substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes,
The bacterial solutions of the irradiated sample and the sample maintained under light-shielded conditions were 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. With respect to abrasion resistance, sliding wear using a plastic eraser was performed, and changes in appearance were compared and evaluated. The following ceramic tile as a substrate in (Table _{1), SiO 2 -Al 2 O} 3 -Na / K 2 O in the binder
It shows changes in antibacterial properties and abrasion resistance due to changes in firing temperature when frit is used.

[0053]

[Table 1]

Here, SiO ₂ used as a binder was used.
The specific gravity of -Al ₂ O ₃ -Na / K ₂ O frit was 2.4, the film thickness when applied was 200 μm, and the softening temperature was 680 ° C. The TiO ₂ obtained in (Table 1) was No. 1
~ 3 are anatase type, specific gravity is 3.9, N
o. About 4 and 5, it was a rutile type and specific gravity was 4.2.

In Table 1, no. In No. 1, since the firing temperature was only 20 ° C. higher than the softening temperature of the binder and the viscosity of the binder did not become sufficiently low, the anatase TiO ₂ particles constituting the lowermost layer of the photocatalyst layer were sufficiently embedded in the binder layer. Therefore, in the abrasion resistance test, scratching was caused by 5 to 10 times of sliding and peeled. Regarding antibacterial properties, it is an anatase type excellent in photocatalytic activity, and at 300 ° C. or higher, TG-DTA observation of TiO ₂ sol shows that organic components are almost decomposed and vaporized, and surface treatment agents attached to TiO ₂ surface It is understood that the dispersant is naturalized. However, since the firing temperature was 700 ° C. and the processing temperature was much higher, an excellent value of ++ was obtained.

No. For 3 to 5, the sintering temperature is 800 ° C or higher and 1
000 ° C. or lower, but the durability is 40
It was extremely excellent without any change in the sliding test more than once. This may be due to the formation of a neck due to the initial firing of the TiO ₂ particles on the surface. 1100 ° C
In the case of the treatment, the TiO ₂ layer on the surface of the multifunctional material removed from the roller hearth kiln after cooling and solidification had cracks. Judging from the TMA measurement of the TiO ₂ test piece, this is considered to be due to the medium-term sintering accompanied by significant volume shrinkage of the TiO ₂ particles.

No. The antibacterial properties of the samples 4 and 5 were all negative. There are two possible causes for this. One is T
Another reason is that the iO ₂ particles have undergone a phase transition to the rutile type.
It is conceivable that the TiO ₂ particles constituting the photocatalyst layer were buried in the binder layer because the temperature was too high and the viscosity of the binder was too low. Here, it cannot be considered that the only cause is that the TiO ₂ particles undergo a rutile-type phase transition. This is because rutile-type TiO ₂ has some photocatalytic activity, though it is inferior to anatase-type TiO ₂ . For example, TiO directly on porous alumina substrate
_{2 The} sol was spray-coated, baked at 950 ° C., and then cooled and solidified, and the antibacterial property of the sample was +. Therefore, the sintering temperature is higher than the softening temperature of the binder by more than 300 ° C., and the viscosity of the binder is too low, so that the T
It is understood that the fact that the iO ₂ particles are buried in the binder layer is also a factor.

Further, by elemental analysis of Ti and Si (main component of binder) by EPMA or the like in the cross-sectional direction of the sample, a layer in which Ti and Si are mixed is observed, and TiO _{2 as} photocatalyst particles is embedded. Was confirmed.

Reference Example 1 described above, that is, at least the photocatalyst was TiO ₂ and the binder layer was SiO ₂ —Al ₂ O ₃ —Na /
In the case of the K ₂ O frit, the following was confirmed.
When the multifunctional material is manufactured under the condition that the sintering temperature is higher than the softening temperature of the binder by more than 20 ° C. and not higher than 300 ° C., the multifunctional material having good antibacterial property and abrasion resistance can be manufactured. It is considered that the cause is that the viscosity of the binder is adjusted to a value at which the TiO ₂ can be appropriately embedded in the binder layer in the above temperature range. In the multifunctional material prepared in the above, embedding of TiO ₂ particles in the binder layer was confirmed. When the firing temperature was 800 ° C. or more and 1000 ° C. or less, the abrasion resistance was extremely excellent without any change even in a sliding test of 40 times or more. TiO
_This is thought to be due to the strong bond associated with the formation of the neck between the _two particles.

Reference Example 2 A 100 × 100 × 5 alumina base material (alumina purity: 96)
%), A binder layer composed of SiO ₂ —Al ₂ O ₃ —PbO frit is formed by a spray coating method, dried, and then spray-coated with a 15% TiO ₂ sol aqueous solution (same as in Reference Example 1). Apply by method,
A TiO ₂ layer having a thickness of 0.8 μm is formed, and then the base material on which the binder layer and the TiO ₂ layer are laminated is heated and fired with a roller hearth kiln at different ambient temperatures for each example, and then cooled. Solidified to obtain a multifunctional material.

The following Table 2 shows changes in antibacterial properties and abrasion resistance with changes in firing temperature when alumina was used as the base material and SiO ₂ -Al ₂ O ₃ -PbO frit was used as the binder.

[0062]

[Table 2]

Here, SiO ₂ used as a binder was used.
The softening temperature of the —Al ₂ O ₃ —PbO frit was 540 ° C., the specific gravity was 3.8, and the film thickness when applied was 150 μm.
The crystal forms of TiO ₂ obtained were all anatase.

In the abrasion resistance test of (Table 2), no.
No. 6 was scratched and stripped by sliding less than 10 times, No.7 and 8 were not damaged by sliding more than 10 times.
In addition, No. Good results were obtained in Nos. 9 and 10, in which no damage was caused even after sliding more than 40 times.

No. In did not enter scratched even 40 times or more sliding 9,10, because the firing temperature of 800 ° C. or higher, the neck is produced between the TiO ₂ particles, probably because TiO ₂ particles to each other tightly bound Can be No. The reason for scratching and peeling by sliding 10 times or less at 6 is that the firing temperature is only 20 ° C. higher than the softening temperature of the binder,
It is considered that the anatase TiO ₂ particles constituting the lowermost layer of the photocatalyst layer were not sufficiently embedded in the binder layer because the viscosity of the binder did not become sufficiently low. On the other hand, No. The fact that no scratch was found even after 10 or more slides at 7, 8 was that the difference between the firing temperature and the softening temperature of the binder was not reached, but the viscosity of the binder was TiO _2. It is considered that the value was adjusted to a value that can be appropriately embedded in the binder layer. On the other hand, in the antibacterial test of (Table 2), 6-9 is +
++ or ++, good results were obtained. 10 is +
Became. This is probably because the firing temperature was higher than the softening temperature of the binder by 320 ° C. and the viscosity of the binder was too low, so that the TiO ₂ particles constituting the photocatalyst layer were embedded in the binder layer.

(Reference Example 3) A SiO ₂ —Al ₂ O ₃ —BaO frit was melted in a mold, cooled and solidified in a mold, and processed to produce a 100 × 100 × 1 glass sheet, on which 15% was formed. the TiO ₂ sol solution of (same as in reference example 1) was applied by spray coating method, the film thickness was formed TiO ₂ layer of 0.8 [mu] m. Thereafter, the glass sheet was converted to an alumina substrate (100 × 100 ×
5), baked by heating in a siliconit furnace with different ambient temperatures for each reference example, and then cooled and solidified to obtain a multifunctional material.

The following Table 3 shows changes in antibacterial properties and abrasion resistance of the above-mentioned multifunctional materials according to the firing temperature.

[0068]

[Table 3]

Here, SiO ₂ used as a binder was used.
The softening temperature of the —Al ₂ O ₃ —BaO frit is 620 ° C., the specific gravity is 2.8, and the crystal form of TiO ₂ on the multifunctional material is No. 1
Nos. 1 to 13 are anatase type. 14 was a rutile type.

In the abrasion resistance test of (Table 3), no.
No. 11 was scratched and stripped by sliding less than 10 times. No. 12 was not damaged even by sliding 10 times or more. In the cases of Nos. 13 and 14, good results were obtained in which no damage was caused even when the slide was performed 40 times or more.

No. The reason why no scratch was formed even after the sliding of 40 or more times in 13 and 14 is considered that a neck was formed between the TiO ₂ particles because the firing temperature was 800 ° C. or more, and the TiO ₂ particles were strongly bonded to each other. Can be No. 11 in 1
Scratching and peeling after 0 or less slides occurred because the firing temperature was only 20 ° C. higher than the softening temperature of the binder, and the viscosity of the binder did not become sufficiently low. Anatase TiO ₂ constituting lower layer
This is probably because the particles were not sufficiently embedded in the binder layer. On the other hand, No. The reason that no scratch was made even after sliding 10 times or more in 12 is that the difference between the sintering temperature and the softening temperature of the binder did not reach the temperature at which the neck portion was formed, but the viscosity of the binder was TiO _2. It is considered that the value was adjusted to a value that could be properly buried inside. On the other hand, in the antibacterial test of (Table 3), 11
~ 13 obtained good results as +++ or ++, but N
o. 14 became-. This is because the TiO ₂ is rutile and the firing temperature is 32 degrees lower than the softening temperature of the binder.
This is considered to be due to two causes: the temperature was as high as 0 ° C., the viscosity of the binder became too low, and the TiO ₂ particles constituting the photocatalyst layer were embedded in the binder layer.

From the above, TiO was previously added to the binder.
After applying the _two particles, in the method of obtaining a multifunctional material by sticking to the substrate and firing to obtain a multifunctional material, the same as the method of applying a binder to the surface of the substrate and then applying TiO ₂ particles to obtain a multifunctional material It was confirmed that the effect was obtained.

REFERENCE EXAMPLE 4 An acrylic resin binder was applied to the surface of a 100 × 100 × 5 polyimide resin base material, and then 15% Ti
An O ₂ sol aqueous solution is applied by a spray coating method to form a TiO ₂ layer having a thickness of 0.8 μm, and then the base material on which the binder layer and the TiO ₂ layer are laminated is fired at 150 ° C. in a nichrome furnace. Multifunctional material was obtained.

The following Table 4 shows changes in the antibacterial and abrasion resistances of the above-mentioned multifunctional materials according to the firing temperature.

[0075]

[Table 4]

In Table 4, the method of preparing the 15% TiO ₂ sol aqueous solution was changed as follows. No. 15: The 15% TiO ₂ sol aqueous solution used in Reference Example 1 was used as it was. No. 16: TiCl ₄ aqueous solution in autoclave 11
After hydrolysis at 0-150 ° C., the product is treated with nitric acid to pH 0.
The dispersion was adjusted to 8 without using a surface modifier, and then used after removing aggregates. In this case, spray coating was performed immediately after removing the aggregates.

Here, the specific gravity of TiO ₂ is 3.9, the crystal type is anatase, the specific gravity of the acrylic resin is 0.9, and the temperature at which the viscosity corresponding to the glass softening point is 70 ° C.

Regarding the abrasion resistance, No flaw was found in any of the conditions 15 and 16 even after 10 or more slidings. This is considered to be because the range of the difference between the firing temperature and the softening temperature of the binder was such that the viscosity of the binder could be adjusted to a value at which TiO ₂ could be appropriately embedded in the binder layer.

On the other hand, regarding the antibacterial test, Fifteen
Was-, but No. 16 obtained ++ and a favorable result, and found that a multifunctional material having antibacterial properties can be produced even at less than 30 ° C. This difference is DT
In A-TG, No. 20 for 15 TiO ₂ sols
There are components that decompose and evaporate at 0 to 350 ° C. 1
In No. 6, the presence of an organic component covering TiO ₂ is considered to be the cause. Here, the specific gravity difference between the anatase and the acrylic resin was 3, but it was also confirmed that with such a difference, the TiO ₂ particles constituting the photocatalyst layer had good antibacterial properties without being embedded in the binder layer. .

REFERENCE EXAMPLE 5 A binder layer made of frit or the like having a different specific gravity is formed by spray coating on the surface of a 100 × 100 × 5 alumina substrate, and dried to form a 15% Ti layer.
A TiO ₂ layer having a thickness of 0.8 μm is formed by spray coating an O ₂ sol aqueous solution, and then the base material on which the binder layer and TiO ₂ are laminated is heated and fired at 750 ° C. with a roller hearth kiln. After cooling and solidification, a multifunctional material was obtained.

The following Table 5 shows changes in antibacterial properties and abrasion resistance of the above multifunctional materials with changes in firing temperature.

[0082]

[Table 5]

Regarding the antibacterial test, no. All of 17 to 20 obtained good results of +++. In any case, the sintering temperature is 30 ° C. or higher than the softening temperature of the binder.
This is considered to be because the range of the difference between the sintering temperature and the softening temperature of the binder was high in the range of 0 ° C. or less, and the viscosity of the binder was adjusted to a value at which TiO ₂ could be appropriately embedded in the binder layer. .

Regarding the abrasion resistance, No. 17 was scratched and stripped by sliding less than 5 times. 1
Nos. 8 to 20 showed no scratches even after sliding 10 times or more. The cause is as follows. In the case of No. 17, unlike the others, the specific gravity of the binder is larger than that of TiO ₂ , and it is considered that the anatase TiO ₂ particles constituting the lowermost layer of the photocatalyst layer were not sufficiently embedded in the binder layer. Therefore, it has been found that the abrasion resistance of the multifunctional material is also affected by the specific gravity of TiO ₂ and the binder, and is deteriorated when the specific gravity of the binder is larger than the specific gravity of TiO ₂ .

(Example 6) SiO ₂ —Al ₂ O was applied to the surface of a 150-square ceramic tile base material.
_A binder layer composed of _3- BaO frit (softening temperature: 620 ° C.) is formed, a TiO ₂ sol and a SnO ₂ sol are mixed thereon, and a stirred aqueous solution is applied by a spray coating method, followed by firing at 750 ° C. After cooling and solidification, a multifunctional material was obtained. Note TiO ₂ sol concentration was adjusted to PH11 with NH ₃ aqueous solution at 4～6Wt%, the crystallite diameter of the TiO ₂ particles are 0.01 [mu] m, crystallite through the SnO ₂ particles, 0.
0035 μm.

The multifunctional material thus manufactured was made of TiO.
_The results of the antibacterial test and the abrasion resistance test when the amount of SnO ₂ to ₂ (molar ratio) was variously changed are shown in Table 6 below.

[0087]

[Table 6]

The abrasion resistance test improved with an increase in the amount of SnO ₂ , and when added in an amount of 10% or more, no damage was caused and no change occurred even in 40 sliding tests. Regarding the antibacterial test, if the range was up to 20% or more, it was +++ as in the case of no addition, and it stopped at ++ up to 60%. If added more, the probability of covering the TiO ₂ particles on the substrate surface increases, the antibacterial property deteriorates,
At 100%, it became-. Therefore, when the amount of SnO ₂ added is 10% or more and 60% or less, preferably 10% or more and 20% or less of the TiO ₂ amount, a multifunctional material having excellent antibacterial properties and abrasion resistance can be provided.

Here, the wear resistance is improved with an increase in the amount of SnO ₂ by the following mechanism. That is, SnO ₂
Figure because of the high vapor pressure at a high temperature of at least 600 ° C. than TiO _2, In the prior sintering interval of the TiO ₂ particles 3b 4
As shown in (a), the surface of the TiO ₂ particles 3b having a positive curvature has a high vapor pressure and a surface having a negative curvature, that is, the surface of the neck portion where the two TiO ₂ particles 3b are in contact with each other. Decreases the vapor pressure. As a result, as shown in FIG. 4 (b), S has a higher vapor pressure than TiO ₂ at the neck.
As shown in FIG. 4C, nO ₂ enters and condenses, and sintering is performed by a vaporization-condensation mechanism. Then, when sintering is performed by the vaporization-condensation mechanism, the sintered Ti
Since the interval L ₂ between O ₂ particles is substantially equal to the interval Lo before sintering,
No cracks or the like occur. In the composite member in which the TiO ₂ particle layer is held on the base material surface via the binder as described above, if the SnO ₂ particles are filled in the gaps between the TiO ₂ particles exposed at the outermost surface and fired at 600 ° C. or more, cracks may occur. Since the neck portion between the TiO ₂ particles can be bonded without generating cracks, the wear resistance is improved.

[0090] (Comparative Example 7) SiO ₂ on the surface of the pottery quality tile substrate 150 corner as in Example 6 -Al ₂ O ₃ -BaO frit (softening temperature 620
C.) and a TiO ₂ layer is formed thereon.
The aqueous solution obtained by mixing and stirring the sol and the SiO ₂ sol was applied by a spray coating method, and then baked at 750 ° C. and cooled and solidified to obtain a multifunctional material. The TiO ₂ sol concentration is 4 ~
The pH was adjusted to pH 11 with an aqueous NH ₃ solution at 6 wt%, and the crystallite size of the particles was 0.01 μm as in Example 6, but Sn
Crystallite size of O ₂ particles with somewhat larger particles 0.008 .mu.m.

An antibacterial test and an abrasion resistance test were performed on the multifunctional material thus produced, and the results of comparison with Example 6 are shown in Table 7 below.

[0092]

[Table 7]

[0093] As a result, the effect of improving wear resistance of the SnO ₂ particles 0.008μm is, SnO of 0.0035Myuemu ₂
It was weaker than when the particles were used, and when the molar ratio with respect to the TiO ₂ particles was 60% or more, no damage was caused even in the sliding test for 40 times, and no change occurred. In the antibacterial test, as in the case of using the SnO ₂ particles of 0.0035 μm, if the range was up to 20% or more, it was +++ as in the case of no addition, and if it was 60% or less, it stopped at ++. If more is added, the probability of covering the TiO ₂ particles on the substrate surface increases, and the antibacterial property deteriorates.
It became. Therefore, when 0.01 μm TiO ₂ particles are used, it is difficult to add 0.008 μm SnO ₂ particles to provide a multifunctional material having excellent antibacterial properties and abrasion resistance. This is because the vapor pressure of the SnO ₂ particles decreases as the particle size increases, and when the SnO ₂ particles remaining without vaporization are 0.0035 μm, they are present in the gaps between the TiO ₂ particles to improve the bonding strength. I did,
At 0.008 μm, compared to the gap between TiO ₂ particles, S
This is probably because the large size of the nO ₂ particles does not allow the SnO ₂ particles to enter the gaps, but rather increases the probability of coming on the TiO ₂ particles. The size of the SnO ₂ particles should fill the gap of the TiO ₂ particles from the above, compared TiO ₂ particle size is preferably less than 4/5.

(Reference Example 8) On the surface of a 150 square porcelain tile base material, SnO ₂ -Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 620 ° C.) is formed, and a TiO ₂ sol aqueous solution is applied thereon by a spray coating method, and then baked at 750 ° C. to be cooled and solidified. ₍₂₎ After applying the sol aqueous solution by a spray coating method, a heat treatment was performed at 110 ° C. to obtain a multifunctional material. At this time, the same TiO ₂ sol aqueous solution as in Example 6 was used, and the SnO ₂ sol was 0.0035 μm.
m was used.

The results of the antibacterial test and the abrasion resistance test performed on the multifunctional material thus produced are shown below (Table 8).
Shown in

[0096]

[Table 8]

The abrasion resistance test improved as the amount of SnO ₂ increased, and 4% was added when the molar ratio was 20% or more.
Even in the zero-time sliding test, no damage was found and no change occurred. For the antibacterial test, if it is in the range up to 20% or more, it is +++ as in the case of no addition, and 60%.
Stopped at ++ up to%. When added more, the probability of covering the TiO ₂ particles on the surface of the substrate increased, and the antibacterial property deteriorated. In this test, since the SnO ₂ sol was heat-treated at a low temperature of 110 ° C.,
Although the sintering by the vaporization-condensation mechanism did not occur, the abrasion resistance was improved, but the particle size was smaller than the TiO ₂ particles, that is, SnO ₂ particles having a large specific surface area and excellent adsorption power. There by filling the gap of the TiO ₂ particles, presumably because bonding of TiO ₂ particles was strengthened.

(Reference Example 9) The surface of a 150 square porcelain tile base material was coated with SiO ₂ -Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 620 ° C.) is formed, and a TiO ₂ sol aqueous solution is applied thereon by a spray coating method, and then calcined at 750 ° C. to be cooled and solidified. A copper aqueous solution was applied and dried, and then irradiated with light including ultraviolet rays to fix copper ions on the photocatalyst layer while reducing the copper ions, thereby obtaining a multifunctional material. Here, a mercury lamp was used as the irradiation lamp. Here, the average size of the Cu particles fixed to the photocatalyst layer was about 0.004 μm.

The results of the antibacterial test and the abrasion resistance test performed on the multifunctional material thus produced are shown in Table 9.

[0100]

[Table 9]

The wear resistance test improved with an increase in the amount of Cu, and the addition of a molar ratio of 20% or more did not cause any damage or change even in the 40 times of the sliding test. Regarding the antibacterial test, if the range was up to 20% or more, it was +++ as in the case of no addition. Since Cu itself has an antibacterial activity, deterioration of the antibacterial activity by adding a large amount was not observed. However, it may be considered that the photocatalytic action of the TiO ₂ particle layer is dominant when the added amount of Cu is small, and the effect of Cu is dominant when the added amount of Cu is large. C
In the case of expecting the action of only u, Cu is gradually eluted when used in a liquid. Therefore, it is considered that the life is shorter than that without the photocatalyst. Also, when the amount of Cu added becomes large, the cost increases accordingly. Therefore, it seems that it is meaningless to set the Cu amount too large. According to this example, it was confirmed that not only an oxide such as SnO ₂ but also a metal such as Cu can be a particle that fills the gap of the TiO ₂ particle layer.

Reference Example 10 A SiO ₂ —Al ₂ layer was formed on the surface of a 150 square porcelain tile base material.
A binder layer composed of an O ₃ —BaO frit (softening temperature: 620 ° C.) is formed, and a TiO ₂ sol aqueous solution is applied thereon by a spray coating method, and then calcined at 950 ° C. to be cooled and solidified. A copper aqueous solution was applied, and thereafter, irradiation with light including ultraviolet rays was performed to fix copper ions on the photocatalyst layer while reducing the copper ions, thereby obtaining a multifunctional material. At this time, irradiation was performed for several minutes using a BLB lamp as an irradiation lamp. TiO ₂ undergoes a phase transition from anatase to rutile during the heat treatment process. Ti
O ₂ film thickness 0.4 μm for spray coating
Was adjusted.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test. Regarding the abrasion resistance test, good results are shown in this temperature range even without addition. C
Even in the case where u was added, no damage was caused in the sliding test for 40 times as in the case of no addition, and no change occurred.
The antibacterial test is shown in FIG. When not added, Ti
O ₂ is bad because it is rutile. The antibacterial property of adding Cu increased. The Cu loading amount is 0.7 μg / cm not only when the BLB lamp is irradiated but also when the irradiation is not performed.
^When it becomes ² or more, the antibacterial activity becomes ++, and when the amount of supported Cu becomes 1.2 μg / cm ² or more, the antibacterial activity becomes +++. From the above, in order to provide a multifunctional material excellent in both antibacterial properties and abrasion resistance, the amount of supported Cu is 0.7 μg / cm ^2.
And more preferably 1.2 μg / cm ² or more.

Incidentally, the amount of supported Cu is dramatically improved when a drying step is performed after the application of the aqueous solution of copper acetate and before the irradiation with the BLB lamp. FIG. 6 shows the relationship. This is presumably because the concentration of metal ions when photoreduced is higher when dried.

The amount of supported Cu is maximized when the amount of applied Cu is optimized (FIG. 7 is an example of copper acetate having a Cu concentration of 1 wt%). In the case of FIG. 7, the amount of consumed Cu is 0.7 μg / cm.
^{For 2} or more, the amount of Cu applied is 0.2 mg / cm ² or more
Cu consumption is reduced to 1.2 μg / cm ² or less to 2.7 mg / cm ² or less.
To cm ² or more is a Cu coating weight 0.3 mg / cm ² or more
The upper limit may be 2.4 mg / cm ² or less.

(Reference Example 11) The surface of a 150 square porcelain tile base material was coated with SiO ₂ -Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 680 ° C.) was formed, and a TiO ₂ sol aqueous solution was applied thereon by a spray coating method, and then calcined at 950 ° C. to be cooled and solidified. An aqueous solution was applied, dried, and then irradiated with light including ultraviolet rays to reduce silver ions and fix the silver ions on the photocatalyst layer to obtain a multifunctional material. At this time, irradiation was performed for several minutes using a BLB lamp as an irradiation lamp. Also T
iO ₂ undergoes a phase transition from anatase to rutile during the heat treatment process. The thickness of TiO ₂ was adjusted to 0.4 μm during spray coating.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test. Regarding the abrasion resistance test, good results are shown in this temperature range even without addition. A
Even when g was added, no damage was caused and no change occurred in 40 sliding tests as in the case where no g was added.

[0108] For the antibacterial test, T is the time of the additive-free
Poor because iO ₂ is rutile. The addition of Ag increased the antibacterial properties. The Ag loading amount is 0.05 μg not only when the BLB lamp is irradiated but also when the irradiation is not performed.
/ Cm ² or more, the antibacterial activity becomes ++, and the Ag carrying amount becomes 0.1 μg / cm ² or more, the antibacterial activity becomes +++.
Becomes Therefore, in order to provide a multifunctional material excellent in both antibacterial properties and abrasion resistance, the amount of Ag supported is 0.05 μg / cm.
^It is preferably at least ² , more preferably at least 0.1 μg / cm ² . However, when the amount of Ag carried is large, the color is changed from brown to black, and the appearance is poor. However, the amount of Ag carried was 1 μg /
If it is less than cm ^2, there is no coloring. From the above, the Ag carrying amount is preferably 0.05 μg / cm ² or more and 1 μg / cm ² or less, more preferably 0.1 μg / cm ² or more and 1 μg / c.
m ² or less is good.

Reference Example 12 The surface of a 150-square earthenware tile substrate was coated with SiO ₂ —Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 680 ° C.) was formed, and a TiO ₂ sol aqueous solution was applied thereon by a spray coating method, and then calcined at 950 ° C. to be cooled and solidified. An aqueous solution was applied, dried, and then irradiated with light including ultraviolet rays to reduce silver ions and fix the silver ions on the photocatalyst layer to obtain a multifunctional material. At this time, irradiation was performed for several minutes using a BLB lamp as an irradiation lamp. Also T
iO ₂ undergoes a phase transition from anatase to rutile during the heat treatment process.

For the multifunctional material thus produced, Ti
The abrasion resistance test, antibacterial test and stain resistance test were carried out by changing the thickness of O ₂ to various values. Regarding the abrasion resistance test, good results were obtained in the range of 2 μm or less tested this time, and no damage was caused and no change occurred in the 40 times of the sliding test. In the antibacterial test, the film thickness becomes ++ when the film thickness is 0.1 μm or more and ++ when the film thickness is 0.2 μm or more. Therefore, the thickness of TiO ₂ is preferably 0.1 μm or more, and more preferably 0.2 μm or more.

(Reference Example 13) The surface of a 150 square ceramic porcelain tile base material was coated with SiO ₂ -Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 620 ° C.) is formed, a zinc chloride aqueous solution or a TiO ₂ sol aqueous solution is applied thereon by a spray coating method, dried, and then a silver nitrate aqueous solution is applied, and then ultraviolet rays are applied. And fixed to the photocatalyst layer while reducing silver ions by irradiation with light. Thereafter, it was baked at 900 ° C. or more and 1000 ° C. or less and solidified by cooling to obtain a multifunctional material. At this time, the irradiation lamp is BLB
Irradiation was performed for several minutes using a lamp. Also, TiO ₂ changed its phase from anatase to rutile during the heat treatment process. Further, the Ag whose surface was fixed changed from brown-black to white with the heat treatment, and it is considered that it changed to silver oxide during firing. However, the fixation of Ag was discretely performed, and almost no growth of Ag particles before and after firing was observed.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test. Regarding the abrasion resistance test, good results are shown in this temperature range even without addition. A
Even in the case where g was added, no damage was caused even in the sliding test for 40 times as in the case where no g was added, and no change occurred. For antimicrobial tests, when no additives bad because TiO ₂ is rutile +. The addition of Ag increased the antibacterial properties.

Reference Example 14 The surface of a 150 square porcelain tile base material was coated with SiO ₂ —Al ₂
A binder layer made of O ₃ —BaO frit (softening temperature: 620 ° C.) is formed, and a TiO ₂ sol aqueous solution is applied thereon by a spray coating method.
An aqueous solution of silver nitrate is applied to the composite member which has been baked at a temperature of 00 ° C. or less and cooled and solidified, and then irradiated with light including ultraviolet rays to fix silver ions on the photocatalyst layer while reducing the silver ions. KI aqueous solution was applied at a rate of 0.1 cc / cm ² and further irradiated with ultraviolet rays for about 5 seconds to obtain a multifunctional material. At this time, the loading amount of Ag was 2 μg / cm ² . 0.
By applying a 1 mol / l KI aqueous solution at a rate of 0.1 cc / cm ² and further irradiating ultraviolet rays for about 5 seconds,
The brown-black multifunctional material was decolorized to white, and the appearance was improved.

(Reference Example 15) On the surface of a ceramic tile substrate of 150 squares, SiO ₂ —Al ₂
A binder layer composed of an O ₃ -BaO frit (softening temperature: 620 ° C.) is formed, a TiO ₂ sol aqueous solution is applied thereon by a spray coating method, and then baked at 820 ° C. to be cooled and solidified to obtain a multi-function. The material is placed at an angle, and while irradiating the light containing ultraviolet rays onto the multi-functional material, the bath water collected in the public bath is continuously dropped on the multi-functional material while circulating, changing the bath water. Was observed. For comparison, a similar device was dropped on a substrate having no photocatalyst layer. In the observation 14 days later, the bath water dropped on the multifunctional material showed a unique difference in the degree of turbidity as compared with the bath water dropped on the substrate not provided with the photocatalytic layer. Although it was not possible, there was a difference in the water odor. That is, in the bath water that was dropped on the substrate without the photocatalyst layer, a quite strong water odor was observed, and slime-like slime and organic precipitates were observed on the substrate, None of the bath water was dropped on the multifunctional material. According to the above simulation experiments, it is considered that this multifunctional material can be used as an artificial waterfall or water fountain paving stone in a water circulation system in parks, department stores, and the like.

[0115]

As is apparent from the above description, according to the present invention, the photocatalyst particles are fixed via the binder layer made of a material lower than the softening temperature of the base material. Since the photocatalyst particles constituting the photocatalyst particles are not buried in the binder layer, the surface of the photocatalyst particles is substantially exposed to the outside, and the photocatalytic effect can be sufficiently exhibited. Further, among the photocatalyst particles, some of the particles constituting the lower layer of the photocatalyst layer are buried in the binder layer, so that the holding power of the photocatalyst layer is greatly improved, and peeling or the like hardly occurs.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for producing a multifunctional material having a photocatalytic function according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1 (d).

FIG. 3 is an enlarged view between TiO ₂ particles.

FIGS. 4A to 4C are diagrams for explaining a mechanism of sintering of TiO ₂ particles.

FIG. 5 is a graph showing test results of an antibacterial test.

FIG. 6 is a graph showing test results on the amount of supported Cu when a drying step is performed before irradiation with a BLB lamp.

FIG. 7 is a graph showing the relationship between the amount of Cu carried and the amount of Cu applied;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Binder layer, 3 ... Photocatalyst layer, 3
a: photocatalyst particles constituting the lower layer of the binder layer side of the photocatalyst layer; 3b: photocatalyst particles constituting the surface layer of the photocatalyst layer which is in contact with the outside air; 3c: particles filled for bonding the photocatalyst particles.

Continuation of the front page (72) Eiichi Kojima 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Totoki Co., Ltd. (72) Mitsuyoshi Machida 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka No. 1 Toto Kiki Co., Ltd. (72) Yoshimitsu Saeki 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture 1-1 Touchi Kiki Co., Ltd. (72) Tatsuhiko Kuga Nakajima, Kitakyushu-shi, Fukuoka 2-1-1, Totoki Kiki Co., Ltd. (72) Yasushi Nakajima 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Totoki Kiki Co., Ltd. (56) References JP-A-5-253544 (JP, A) JP-A-1-288321 (JP, A) JP-A-2-503 (JP, A) JP-A-5-309267 (JP, A) JP-A-1-218635 (JP, A) JP-A-61-146345 (JP, A) JP-A-7-265714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 21/00-38/74

Claims (2)

(57) [Claims] 1. A multifunctional material having a photocatalytic function in which a titanium oxide particle layer as a photocatalyst is held on a base material surface via a binder layer, wherein the upper layer of the titanium oxide particle layer is in contact with the outside air. The lower layer portion of the titanium oxide particle layer is partially buried in the binder layer, and in the gap between the titanium oxide particles constituting the surface layer exposed from the binder layer in the titanium oxide particle layer. Particles smaller than the gap are filled to sinter the titanium oxide particles, and particles smaller than the gap are tin oxide, zinc oxide,
Particles which are any of bismuth oxides and have a particle size smaller than the gap are present at the neck portion between the titanium oxide particles, and the average particle size of the titanium oxide particles constituting the titanium oxide layer is 0. A multifunctional material having a photocatalytic function, which is less than 3 μm. 2. The multifunctional material having a photocatalytic function according to claim 1, wherein the base material is a tile.