JPH11226422A - Powdery photocatalyst body, composition for photocatalyst, photocatalyst body and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a powdery photocatalyst body excellent in processability and light resistance by microencapsulating aggregated particles of TiO2 as a core material with a silica-base wall material. SOLUTION: Metatitanic acid obtd. by hydrolyzing titanyl sulfate under the condition of high seed addition is fired at a low temp. of <=700 deg.C to form anatase type titanium dioxide having 10-50 nm primary particle diameter. Aggregated particles of the titanium dioxide having 300-800 nm particle diameter are used as a core material and microencapsulated with a silica-base wall material to obtain the objective powdery photocatalyst body having 0.5-200 μm particle diameter, 50-400 m<2> /g specific surface area and 1-1,000 nm pore diameter. This photocatalyst body can keep its photocatalytic function high, has good dispersibility in a resin and is easy to handle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a photocatalyst powder having a microcapsule structure using titanium dioxide having a photocatalytic function, a composition for a photocatalyst using the powder, a photocatalyst coated with the composition, and The present invention relates to uses such as a photocatalyst powder or a deodorant using the photocatalyst.

[0002]

2. Description of the Related Art It is widely known that when a photocatalyst such as titanium dioxide is irradiated with ultraviolet rays, electrons are transferred from a valence band to a conduction band by photoexcitation to form an n-type semiconductor, which exhibits decomposition and sterilization effects of various compounds. Decomposition of underwater organic matter ("Water and wastewater" vol. 30 No. 10 (1988) p.
943-948), organic matter decomposition, deodorization, sterilization ("surface")
vol.25 No.8 (1987) p477-495,
"Ceramics" 21 (1986) No. 4, p326
-333).

However, when the photocatalytic activity is actually used for the purpose of decomposing and removing harmful gas in exhaust gas, odorous gas such as tobacco and toilets, harmful substances such as pesticides, environmental pollutants, etc. For ease of use, it is necessary to carry and fix it on some kind of substrate. In addition, powders of various functional substances, such as deodorants, which have been recently developed, are rarely used in the form of powder.

As an example of the functional substance powder, the following method has been proposed as a method for supporting titanium dioxide for a photocatalyst on a substrate.

(1) Films, beads, and the like made of a light-transmitting substance such as nitrocellulose, glass, polyvinyl chloride, nylon, methacrylic resin, and polypropylene.
A method in which titanium oxide fine powder is adhered to a substrate such as a board or a fiber (Japanese Patent Application Laid-Open No. 62-66861).

(2) Titanium (IV) on a porous glass support
Impregnated with an alcohol solution of tetrabutoxy oxide,
A method of heating and converting to titanium oxide of the anatase type to hold and fix it on a porous glass support (Japanese Patent Laid-Open No.
-50154).

(3) The semiconductor catalyst powder is retained by a method such as press-fitting, impregnating, or adhering into a porous polymer film (for example, a polyfluoroethylene resin) having a photosensitizer such as a dye or a metal complex as a side chain. .Fixing method (Japanese Patent Laid-Open No. 58-125)
602).

(4) A method in which titanium oxide is supported on a filter made of polypropylene fiber or ceramics (JP-A-2-68190).

(5) A method in which a titanium dioxide powder is held and fixed in the entanglement of quartz, glass, and plastic fibers, and both surfaces thereof are held down with light-transmitting glass (US Pat. No. 4,888,101).

(6) Platinum is fixed to an alumina substrate by a sputtering method, and a mixed dispersion of an anatase type titanium oxide powder and an organic solvent solution of methyl methacrylate is applied thereon by a spin coating method. A method of thermally decomposing methyl methacrylate as a binder and converting anatase type titanium oxide to rutile type titanium oxide (Robert E. Hetri
c, AppliedPhysicsCommunica
tions, 5, (3), 177-187 (198
5)).

(7) A method of spray-supporting titanium oxide on the surface of a polyester cloth by a low-temperature thermal spraying method (T. Sakurada, Surface Technology Vol. 41, No. 10, P60 (1990)).

(8) A method of adhering photocatalyst particles to a substrate via a hardly decomposable binder (Japanese Patent Application Laid-Open No. 7-171408).

The above-described known methods for supporting the photocatalytic titanium dioxide on the substrate have the following disadvantages.

In the fixing with an organic binder such as (1), (3), (4) and (5), most of the organic substances are decomposed by the photocatalytic action of titanium dioxide. Not reliable. In the method (2), since an expensive organic titanium compound is used as a raw material, and the glass is directly supported on a glass which is easily broken, the strength is not reliable. (6),
The method (7) is not preferable because the temperature becomes extremely high during fixing and the high photocatalytic activity of titanium dioxide is lost.

In the method (8), a hardly decomposable binder is used. However, as long as the binder is in contact with the photocatalyst, the resin is eventually degraded. It cannot be used for a long time.

Other commonly used methods include simply impregnating and supporting slurry of titanium dioxide or titania sol on an inorganic porous material or fiber, or hydrolysis or heat melting of a silica-based or alumina-based alkali salt. There is a method of using a binder that has been used, but in the former case, the titanium dioxide particles are not fixed, so they easily fall off due to vibration and impact, and in the latter, the binder for fixing the catalyst causes the catalyst surface to be removed. Is coated and the activity is largely lost.

Further, since these methods require heat resistance and the like, the types of substrates that can be used are limited, and fixing and processing on a wide surface are difficult, so that the cost is increased and the light energy is sufficiently increased. There was a problem that it could not be used.

Recently, as a method for fixing titanium dioxide for a photocatalyst, titanium dioxide particles are aggregated, and titanium dioxide particles are supported on inorganic particles such as activated carbon.
Titanium dioxide particles are coated with an inorganic substance such as silica or alumina, etc. to reduce the number of contact points in easily decomposed materials such as paper, or by mixing titanium dioxide for photocatalyst with cement etc. It has been announced that the method is relatively close to practical use.

However, the former cannot prevent decomposition at the point of contact with the titanium dioxide for photocatalyst, and the latter wastes expensive titanium dioxide for photocatalyst inside the cement and has an amount that does not reduce the strength of the cement itself. In the catalyst,
There are still disadvantages such as the effect cannot be expected. Further, the complexity of performing these processes and processing hinders practical use.

The above problems are caused by a photocatalyst other than titanium dioxide,
Furthermore, it is common to all highly active substances such as adsorbents and bactericides.

Accordingly, when these highly active substances are put to practical use, there has been a demand for a fixing method which is excellent in strength and easy to handle without lowering the activity.

[0022]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is intended to solve the above-mentioned problems by using the photocatalytic activity of titanium dioxide to produce an odorous gas such as acetaldehyde and mercaptan.
Harmful gas such as NO _X, harmful substances agricultural chemicals, excellent photocatalyst powder decomposition removal and sterilization effects of environmental pollutants, photocatalytic composition powder with powder and said utilizing photocatalyst composition It is an object of the present invention to provide a photocatalyst in which a photocatalyst powder is supported on a substrate and has excellent workability and light resistance.

[0023]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object, and as a result, a titanium dioxide having photocatalytic activity as a core material and a wall material containing silica as a main component were used. photocatalyst powder microencapsulated, indicates only acetaldehyde, malodorous gases mercaptan, harmful gases such as NO _X, harmful substances agricultural chemicals, good properties in photocatalytic activity such as decomposition and removal and sterilization of environmental pollutants In addition, the present inventors have found that they are extremely easy to make into a paint and that they are extremely excellent in light resistance when formed into a coating film, and have completed the present invention.

That is, according to the present invention, the particle size is 10 to 50 nm.
The photocatalyst powder is characterized in that titanium dioxide in which primary particles are aggregated to form aggregated particles is used as a core material, and is microencapsulated with a wall material mainly containing silica.

The photocatalyst powder has a particle size of 0.5 to 200.
μm, specific surface area 20-1000 m ² / g, pore size 1-1
It is preferably 000 nm.

The photocatalyst powder can be dispersed in a resin to form a photocatalyst composition.

The composition for photocatalyst is applied to a substrate,
A photocatalytic coating can be formed on the substrate to form a photocatalyst.

The substrate is made of aluminum, iron, titanium,
It can be selected from the group consisting of nickel, chromium, copper, alloys containing one or more of the above metals, glass, ceramics, cement, wood, paper and synthetic resins.

Further, the substrate can be selected from the group consisting of cloth, fiber, film and plate.

The photocatalyst powder or photocatalyst can be used as a deodorant, an antibacterial agent, a harmful gas remover, or a water purifier.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The titanium dioxide used as the core material of the photocatalyst powder of the present invention is not particularly limited as long as it has photocatalytic ability, but typically, titanyl sulfate is added under high seeding conditions. Metatitanic acid obtained by the hydrolysis reaction is anatase type calcined at a low temperature of 700 ° C. or less, and the primary particle diameter is adjusted to 10 to 50 nm and the aggregate particle diameter is adjusted to 300 to 800 nm. It can be suitably used. The specific surface area is 20 to 400 m ² / g are preferred, more preferably 50 to 400 m ² / g.

The titanium dioxide includes W, Sn, M
Metal oxides such as o, V, Mn, and Zn that improve the catalytic activity can also be contained.

Microencapsulation with a wall material containing silica as a main component can be carried out, for example, according to the method described in JP-A-62-212316. Therefore, the particle diameter of the photocatalyst powder microencapsulated with the wall material containing titanium dioxide as a core material and silica as a main component is 0.5%.
２００200 μm, specific surface area 20-1000 m ² / g, preferably 50-400 m ² / g, pore size 1-1000 n
m. Those having a particle size of less than 0.5 μm and those having a specific surface area of more than 1000 m ² / g are not preferred because they are difficult to produce due to the production method of the present photocatalyst powder. Further, those having a particle size of more than 200 μm and a specific surface area of less than 20 m ² / g are not preferred because the irradiation efficiency of ultraviolet rays is reduced.

In the present photocatalyst powder having a particle size of, for example, 5 μm, about 300 aggregated particles of the titanium dioxide are included, and the wall material mainly composed of silica has a structure that wraps around it. Instead of covering the entire surface of the titanium dioxide particles in a film form, they are partially contact-bonded. Therefore, even though the wall material mainly composed of silica covers the surface of the aggregated particles of titanium dioxide, the surface of the primary particles of titanium dioxide exists as active sites that are hardly coated with silica. As a result, despite being microencapsulated,
The photocatalytic ability of titanium dioxide is kept high.

The above-mentioned photocatalyst powder can be used alone, but it is preferable to use it as a photocatalyst fixed on some kind of substrate from the viewpoint of its use. For this purpose, a photocatalyst coating composition dispersed in a resin is used. It is preferably applied to the substrate surface.

In the coating composition, the photocatalyst powder is dispersed in a resin. The particle size of the photocatalyst powder is 0.5 to 200 μm, and the particle size of titanium dioxide used for the core material is The dispersion state is very good. It is sufficient that the photocatalyst powder is mixed and dispersed in the resin by using a usual dispersing apparatus for the dispersing method.

The resin may be either thermosetting or heat-softening. The resin is not affected by photocatalytic activity, and is absorbed by titanium oxide contained in the capsule. Almost any material such as vinyl chloride, polyamide, PET, polycarbonate, and methacrylic acid resin can be selected, but those having high light resistance of the resin itself are preferable, and fluorine resin, silicone resin, acrylic resin, light-resistant urethane resin, And a resin modified with fluorine or silicon.

The ratio of the resin to the photocatalyst powder in preparing the coating composition is 15 to 200 parts by weight. When the amount is less than 15 parts by weight, the adhesion of the photocatalyst to the substrate is weak and peeling occurs. When the amount is more than 200 parts by weight, the resin layer becomes too thick, and the odorous gas is less likely to be adsorbed on the functional powder surface, It is not preferable because the photocatalytic reaction efficiency is reduced and the deodorizing performance and the antibacterial performance are reduced.

When the addition ratio of the resin is 50 parts by weight or less, it is preferable to add an appropriate amount of water as a diluent in order to reduce the viscosity at the time of dispersion of the paint.

The photocatalyst according to the present invention is manufactured by applying the coating composition on the substrate to form a coating film. As a method of applying the coating composition on the substrate, a known method can be used, and an appropriate coating method such as application, spraying, and dipping can be selected according to the shape of the substrate.

Although the photocatalyst powder is dispersed in the resin, as described above, since the titanium dioxide is wrapped in the wall material mainly composed of silica, the titanium dioxide hardly comes into contact with the resin. Therefore, the light resistance, which was a problem in the method of fixing with the resin of (1), (3), (4), (5), and (8) described in [Prior Art], is greatly increased in the encapsulated one. And deterioration of the coating film due to the photocatalyst upon irradiation with ultraviolet rays is hardly recognized. At the same time, there are many gaps and pores between the titanium dioxide particles and the wall material mainly composed of silica, and pores having an average pore diameter of 1 nm to 1000 nm leading to the internal space of the wall material mainly composed of silica are also present. since there are countless, these gaps, voids and become desorption of adsorption and reaction product gas of the decomposition gas is facilitated through the pores, aldehydes, malodorous gases mercaptan, harmful gases such as NO _X, of agricultural chemicals, etc. The photocatalytic activity such as decomposition and removal of harmful substances and environmental pollutants and sterilization is greatly improved.

[0042] Incidentally, photocatalytic titanium dioxide for use in the present invention, in addition to deodorization effect of malodorous gases, NO _X, ammonia, harmful substances inorganic gases and pesticides such as hydrogen sulfide, decomposition removal and environmental pollutants Sterilization and removal of fungi and algae are known as photocatalytic effects, and when a deodorizing effect is obtained, it is clear that other effects known as photocatalytic effects can be obtained at the same time. Therefore, the photocatalyst according to the present invention is suitably used as a deodorant, an antibacterial agent and a harmful gas remover.

That is, the photocatalyst can be used as a deodorant to remove odorous gas generated in daily life such as tobacco and toilets. In this case, if a film containing silica sol as a binder component and titanium dioxide as a photocatalyst component is formed on a substrate such as a wall, a plate, a desk, a support, or a box where deodorization is to be performed. Often, the deodorizing effect of the photocatalyst can be exhibited by utilizing sunlight, indoor illumination light, fluorescent light, or the like that enters the room.

The antibacterial agent may be formed by forming the coating film on the lining of a water tank to be subjected to antibacterial treatment, and sterilizing and removing fungi and algae in a container such as a water tank using ultraviolet rays or the like.

Further, the above photocatalyst can be used as a harmful gas remover to remove harmful gases in exhaust gas. The harmful gas here, aldehydes, mercaptans, include ammonia and NO _X, and the like. In this case, a container that allows harmful gas to pass,
The harmful gas can be removed by forming the coating film and irradiating it with sunlight or ultraviolet rays.

Further, a water purifying agent can be obtained by using the above-mentioned photocatalyst. The water referred to here includes industrial wastewater, mining wastewater, industrial water, agricultural water, drinking water, lakes and marshes, river water, seawater, and the like. In this case, the lake shore, river shore, shore, running water channel, reservoir, filter,
Sewerage, or form a coating film on the substrate location that can come into contact with these waters in the aquatic breeding area as a water purification agent,
Next, water containing ultraviolet rays is irradiated to purify the water. Examples of the light containing ultraviolet light include light from sunlight, a fluorescent lamp, a black lamp, a xenon flash lamp, and a mercury lamp.

Further, the photocatalyst powder according to the present invention can be blended with existing cosmetics. That is, a functional cosmetic having an antibacterial effect by decomposing the above-mentioned odor, sebum and the like can be obtained by blending it into a body powder, an antiperspirant and a foundation.

Hereinafter, the content of the present invention will be described in more detail with reference to examples, but these examples are merely examples, and the scope of the present invention is not limited thereto.

[0049]

Example 1 An anatase was added to 1 L of a water glass No. 1 solution having a concentration of 4 mol / L.
Specific surface area of 145 m ² / g, primary particle diameter 20 nm,
110 g of titanium dioxide for photocatalyst having an aggregated particle diameter of 500 nm
And disperse it with stirring, then sorbitan monostearate and polyoxyethylene sorbitan monooleate
(1: 2) A homomixer (HV-ML type manufactured by Tokushu Kika Kogyo Co., Ltd.) together with 5 L of a 3% pharmacological liquid paraffin solution of the mixture.
The mixture was emulsified at 12,000 rpm for 1 minute to prepare a W / O emulsion, added to 15 L of 0.5 mol / L ammonium sulfate solution, reacted, and left for 3 hours. Then, filtration, washing and drying are carried out, and the silica-based microparticles of silicic acid anhydride having a particle size of 5 μm enclosing the titanium dioxide aggregated particles of about 30% by weight, a specific surface area of 350 m ² / g and a pore diameter of 10 nm are used. 300 g of capsules were obtained.

Example 2 An anatase was added to 1 L of a water glass No. 3 solution having a concentration of 4 mol / L.
Specific surface area of 145 m ² / g, primary particle diameter 20 nm,
160 g of titanium dioxide for photocatalyst having an aggregated particle diameter of 300 nm
And disperse it with stirring, then sorbitan monostearate and polyoxyethylene sorbitan monooleate
(1: 2) With a stirrer (three one motor BL-3000, manufactured by Tohshin Kagaku Co., Ltd.) together with 5 L of toluene of the mixture,
The mixture was emulsified at 500 rpm for 1 minute to prepare a W / O emulsion, added to 15 L of a 1.5 mol / L ammonium bicarbonate solution, reacted, and left for 3 hours. Next, filtration, washing, and drying are performed, and the particle diameter containing 180% by weight of the titanium dioxide aggregated particles is 180 μm and the specific surface area is 5%.
380 g of silica-based microcapsules having a wall material of 50 m ² / g and a pore diameter of 50 nm and made of silicic anhydride were obtained.

Example 3 1 L of water glass No. 2 solution having a concentration of 2 mol / L was added to an anatase
Specific surface area of 145 m ² / g, primary particle diameter 20 nm,
After adding 40 g of titanium dioxide for photocatalyst having a coagulated particle diameter of 300 nm and stirring and dispersing the mixture, polyoxyethylene (E
O = 4) Nonylphenyl ether and polyoxyethylene (EO = 10) Nonylphenylether (1: 1) mixed with 5 L of toluene in a homomixer (manufactured by HV-ML type special equipment chemical industry) at 12000 rpm. Emulsify for 1 minute, prepare a W / O emulsion, and further add 3 mol /
The solution was added to 15 L of an L-ammonium sulfate solution, reacted, and left for 3 hours. Next, filtration, washing, and drying were performed, and the particle diameter of the titanium dioxide aggregated particles containing 25% by weight was 0.1%.
5 μm, specific surface area of 900 m ² / g and pore diameter of 10 n
m is silica-based microcapsules with silica as the wall material 1
50 g were obtained.

Example 4 An anatase was added to 1 L of a water glass No. 3 solution having a concentration of 3 mol / L.
Specific surface area of 145 m ² / g, primary particle diameter 20 nm,
100 g of titanium dioxide for photocatalyst having an aggregated particle diameter of 300 nm
, And dispersed by stirring. Then, a homomixer (HV-ML type) is mixed with 5 L of a mixture of polyoxyethylene (EO = 4) nonylphenyl ether (1: 1) and polyoxyethylene (EO = 4) nonylphenyl ether. Emulsified at 12000 rpm for 1 minute with a special machine manufactured by Tokushu Kika Kogyo Co., Ltd.
1 / L calcium chloride solution 15 L
Left for hours. Then, filtration, washing and drying are performed, and the particle diameter containing 20% by weight of the titanium dioxide aggregated particles is 1%.
A wall material having a specific surface area of 70 m ² / g and a pore diameter of 10 nm having a thickness of 10 μm was obtained to obtain 400 g of silica-based microcapsules of calcium silicate.

Example 5 Silica sol having a SiO ₂ concentration of 30% (Snowtex 30)
To 1 L of Nissan Chemical Industry Co., Ltd., 300 g of titanium dioxide for photocatalyst having an anatase type, a specific surface area of 145 m ² / g, a primary particle diameter of 20 nm, and an aggregate particle diameter of 300 nm was added, and the mixture was stirred and dispersed. The mixture was emulsified with a homomixer (manufactured by HV-ML type specialty Kika Kogyo Co., Ltd.) at 6000 rpm for 1 minute together with 5 L of kerosene stearate.
The O-type emulsion was prepared, CO ₂ was blown into the gel to form a gel, and after solid-liquid separation, added to 1 mol of 2 mol / L hydrochloric acid, reacted, and left for 3 hours. Then, filtration, washing and drying are performed, and the silica-based microcapsules of which silicic acid is used as a wall material having a particle diameter of 30 μm, a specific surface area of 450 m ² / g and a pore diameter of 8 nm containing the titanium dioxide aggregated particles at 50% by weight are included. 550 g were obtained.

Experimental Example 1 6 g of the silica-based microcapsules of Example 1 and an acrylic modified silicone resin emulsion (resin content 45%) 15
g and 6 g of pure water together with 60 g of 3 mm glass beads were charged into a 120 ml mayonnaise bottle, and dispersed with a paint conditioner manufactured by Red Devil Co. for 10 minutes to obtain a paint. This was applied to a woven fabric fiber for sheets using a 2 mil doctor blade and dried at 120 ° C. for 30 minutes to obtain a coating film.
This film showed no powder adhesion even when the coated surface was rubbed by hand.

The woven cloth coated with the photocatalyst was 5 cm × 1
cm, into a 120 ml glass bottle, acetaldehyde was injected in an amount such that the gas concentration in the bottle became 100 ppm, and ultraviolet light having a wavelength of 352 nm was applied from outside the bottle to 1.0 m.
After irradiation for 1 hour at W / cm ² , the air in the bottle was measured with a gas chromatograph G3800 (detector FID) manufactured by Yanagimoto Seisakusho, and the acetaldehyde concentration was 0 ppm. Similarly, the purification ability of ethyl mercaptan was measured. As a result, the concentration of ethyl mercaptan after irradiation for 1 hour was 6
It was 0 ppm.

Glacial acetic acid was dissolved in distilled water, and 100 mg /
1 acetic acid solution was prepared. 50 ml of the prepared acetic acid solution was dispensed into a 200 ml beaker, and a 5 cm × 1 cm glass substrate coated with the above photocatalyst was fixed to the bottom of the beaker. 2 ultraviolet radiation 352nm from above at 4 mW / cm ²
After irradiation for 0 hour, the concentration of acetic acid in the solution was measured with an ion chromatograph IC500 manufactured by Yokogawa Electric. As a result, the concentration of acetic acid was reduced to 60 mg / l.

Further, this coating film was coated with a Suga Test Machine Co., Ltd.
Irradiation for 2 hours was performed, but discoloration of coating film and woven fabric,
No peeling of the coating film occurred. In addition, when a paint film peeling test (JIS-K5400) was performed using a pencil hardness, the adhesion was evaluated at a score of 10, and the pencil hardness was 3H or more.

Experimental Example 2 6 g of silica microcapsule powder and acryl-modified silicone resin emulsion 6.7 as described in Example 1 were used.
g and 15 g of pure water were placed in a 120 ml mayonnaise bottle together with 60 g of 3 mm glass beads, and dispersed with a paint conditioner manufactured by Red Devil Co. for 10 minutes to obtain a paint. This was applied to paper with a 2 mil doctor blade and dried at 120 ° C. for 30 minutes to form a coating. This film had no powder adhered even when the coated surface was rubbed by hand.

The paper coated with the photocatalyst was 5 cm × 1 c
m, into a 120 ml glass bottle, acetaldehyde was injected in such an amount that the gas concentration in the bottle became 100 ppm, and ultraviolet light having a wavelength of 352 nm was applied from outside the bottle to 1.0 mW.
After irradiating for 1 hour at / cm ² , the air in the bottle was measured with a gas chromatograph G3800 (detector FID) manufactured by Yanagimoto Seisakusho, and the acetaldehyde concentration was 0 ppm. Similarly, the purification ability of ethyl mercaptan was measured. As a result, the concentration of ethyl mercaptan after irradiation for 1 hour was 30.
ppm.

Further, this coating film was coated with a Suga Test Machine Co., Ltd.
Irradiation for 2 hours was performed, but discoloration of coating film and woven fabric,
No peeling of the coating film occurred.

Experimental Example 3 The paint described in Example 1 was directly applied to an aluminum plate.
No peeling of the coating film occurred. The coating film was irradiated with ultraviolet rays for 72 hours using a Dew Panel Light Control Weather Meter manufactured by Suga Test Instruments Co., Ltd., but no discoloration of the coating film and woven fabric and no peeling of the coating film occurred.

Comparative Example 1 In Example 1, the titanium dioxide for photocatalyst was prepared by adding a specific surface area of 1
A silica-based microcapsule was prepared in the same manner except that titanium dioxide for photocatalyst having only 60 m ² / g and a particle size of 20 nm and consisting of only primary particles was used, and a coating material was prepared in the same manner as in Example 2 using this. And applied to the woven fabric. This film showed no powder adhesion even when the coated surface was rubbed by hand.

When the ability of this coating film to purify acetaldehyde was measured in the same manner as in Example 2, the acetaldehyde concentration after irradiation for 1 hour with ultraviolet light was 50 ppm. The purification ability of ethyl mercaptan was measured in the same manner. As a result, the concentration of ethyl mercaptan after irradiation for 1 hour with ultraviolet light was 80 ppm.
Met.

Comparative Example 2 A coating material was prepared in the same manner as in Example 1 except that the silica-based microcapsule powder was replaced with the titanium dioxide powder for photocatalyst used in the core material, and the coating was applied to a woven fabric. did. This film had no powder adhered even when the coated surface was rubbed by hand. The coating film was irradiated with ultraviolet light for 72 hours using a Suga Test Machine Co., Ltd. due panel light control weather meter. When the coated surface was rubbed with a hand, powder adhered and the coating film peeled off. Was.

Comparative Example 3 A coating material was prepared in the same manner as in Example 1 except that the amount of the acrylic-modified silicone resin emulsion was 1.3 g corresponding to 10 parts by weight and the amount of pure water was 20 g. Coated on cloth. When this film was rubbed by hand, a little powder adhered.

When this coating film was irradiated with ultraviolet light for 72 hours using a Dew panel light control weather meter manufactured by Suga Test Instruments Co., Ltd., the powder adhered when the coated surface was rubbed by hand, Some spalling also occurred.

[0067]

The photocatalyst powder of the present invention has a particle size of 10
Since the core material is titanium dioxide in which primary particles of about 50 nm aggregate to form aggregated particles and are microencapsulated with a wall material mainly composed of silica, the wall material mainly composed of silica is Even if the surface of the titanium aggregated particles is covered, the surface of the primary particles of titanium dioxide exists as an activation site not coated with silica, so that the photocatalytic function of titanium dioxide can be maintained at a high level and the dispersibility in the resin is good. The powder can be easily handled.

The particle size of the photocatalyst powder is larger than the particle size of titanium dioxide used for the core material.
When the specific surface area is 5 to 200 μm and the specific surface area is 20 to 1000 m ² / g, the dispersion state of the powder in the resin can be extremely improved. Further, by setting the pore diameter of the photocatalyst powder to 1 to 1000 nm, the adsorption of the specific decomposition gas and the desorption of the reaction product gas are facilitated, and the photocatalytic activity effect such as decomposition and removal of harmful gas and sterilization is greatly improved. Can be improved.

Further, by dispersing the photocatalyst powder of the present invention in a resin, a photocatalyst composition that can easily form a photocatalyst coating film on a substrate can be obtained.

In the case of a photocatalyst in which a photocatalyst coating film is formed on a substrate using the photocatalyst composition, titanium dioxide having a photocatalytic effect and the resin hardly come into contact with each other in the coating film. The light fastness that had been improved significantly, and also became excellent in workability, deodorant, antibacterial agent,
It can be suitably used as a harmful gas remover, a water purifier and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C09D 5/14 C09D 7/12 Z 7/12 B01J 13/02 E (72) Inventor Koichi Morimitsu Ube City, Yamaguchi Prefecture Inside 1925 Kogushi, 25 Titanium Industries Co., Ltd. No. 2-37, Suzuki Yushi Kogyo Co., Ltd. (72) Inventor Osamu Kuroki 2-1-1 37, Itakano, Higashi-Yodogawa-ku, Osaka, Osaka Prefecture Inside Suzuki Yushi Kogyo Co., Ltd. (72) Inventor Minoru Ueda, Osaka, Osaka Suzuki Yushi Kogyo Co., Ltd. 2-137 Idano, Higashiyodogawa-ku

Claims (10)

[Claims] 1. A photocatalyst powder comprising titanium dioxide as a core material, in which primary particles having a particle size of 10 to 50 nm are aggregated to form aggregated particles, and microencapsulated with a wall material containing silica as a main component. 2. The photocatalyst powder has a particle size of 0.5 to 20.
0 μm, specific surface area 20-1000 m ² / g, pore size 1
The photocatalyst powder according to claim 1, wherein the thickness is 1000 nm. 3. A photocatalyst composition in which the photocatalyst powder according to claim 1 or 2 is dispersed in a resin. 4. A photocatalyst in which the composition for photocatalyst according to claim 3 is applied to a substrate to form a photocatalyst coating film on the substrate. 5. The substrate according to claim 1, wherein the substrate is selected from the group consisting of aluminum, iron, titanium, nickel, chromium, copper, an alloy containing at least one of the metals, glass, ceramics, cement, wood, paper, and synthetic resin. The photocatalyst according to claim 4, characterized in that: 6. The photocatalyst according to claim 4, wherein the substrate is selected from the group consisting of cloth, fiber, film, and plate. 7. A deodorizing agent using the photocatalyst powder according to claim 1 or 2, or the photocatalyst according to any one of claims 4 to 6. 8. An antibacterial agent using the photocatalyst powder according to claim 1 or 2, or the photocatalyst according to any one of claims 4 to 6. 9. A harmful gas remover using the photocatalyst powder according to claim 1 or claim 2, or the photocatalyst according to any one of claims 4 to 6. 10. A water purifying agent using the photocatalyst powder according to claim 1 or 2, or the photocatalyst according to any one of claims 4 to 6.