JP7611005B2 - Photocatalyst spray and photocatalyst coating method - Google Patents

Description

The present invention relates to a photocatalyst coating liquid, a photocatalyst spray, a photocatalyst coating method, and a photocatalyst-coated object.

Generally, deodorizing technologies are broadly divided into four types: chemical deodorization, physical deodorization, biological deodorization, and sensory deodorization. Among these, chemical deodorization methods turn odorous components into odorless components through chemical reactions (neutralization, addition, condensation, oxidation, etc.) between the odorous components and the deodorant components, and are highly effective when the target of the odor is known.
As one type of chemical deodorant, a deodorant that utilizes the strong oxidizing power of photocatalysts has been developed. Many deodorants that utilize photocatalysts have been proposed in the past. There have also been physical deodorants that physically adsorb malodorous components using porous materials such as activated carbon, zeolite, and silica gel, and methods that combine these have also been proposed.
For example, a photocatalytic composite material containing a visible light responsive photocatalyst and a colored earth component that absorbs visible light or a zeolite component that has been processed to be colored has been disclosed (see Patent Document 1). Also, a photocatalytic composition containing a photocatalyst and an adsorbent is known (see, for example, Patent Document 2).

JP 2016-209811 A Special table 2018-516170 publication

The adsorbent contained in the suspension containing the photocatalyst and the adsorbent is a powder with a dispersed particle diameter of several μm or more, so it is prone to aggregation. Therefore, in order to apply this suspension to an object and form a photocatalyst layer in which the adsorbent is uniformly dispersed, it is necessary to suppress the aggregation of particles with a dispersant that disperses the adsorbent. In addition, when a suspension containing a photocatalyst, an adsorbent, a dispersion medium, and a dispersant is sprayed toward an object by a spray, the adsorbent may become charged and statically charged before reaching the object. This charged adsorbent is attracted to a member with a large charged voltage under the influence of the surrounding charged members, and tends to selectively adhere to members that are prone to accumulate static electricity constituting the object, and tends to be fixed unevenly. As a result, uneven application (whitening) occurs and the adsorbent is easily detached from the object.
When an adsorbent is used together with a photocatalyst to adsorb and decompose odorous components, the synergistic deodorizing effect cannot be achieved unless the adsorbent and the photocatalyst are uniformly dispersed on the surface of the object to which they are to be attached.

When a photocatalytic composition containing an earth component or a zeolite component as described in Patent Document 1 is applied to an object, the colored components make the aggregated parts stand out. In addition, even if multiple components are supported on the photocatalytic surface, or a photocatalytic component is supported on a multi-component surface, there is no effect in preventing aggregation, and the aggregation of the components may interfere with the deodorizing ability of the photocatalyst.
The present invention has been made in consideration of the above circumstances, and provides a photocatalyst coating liquid that makes it possible to coat an object with a photocatalyst and inorganic porous fine particles with good film-forming properties.

The present invention provides a photocatalyst coating liquid that is characterized by containing photocatalyst fine particles, inorganic porous fine particles, a non-halogenated hydrophilic non-volatile liquid, and an aqueous dispersion medium.

By applying the photocatalyst coating liquid of the present invention to an object, the object can be coated with a layer (photocatalyst layer) containing photocatalyst fine particles and inorganic porous fine particles having a gas adsorption effect.
Since the photocatalyst coating liquid of the present invention contains an aqueous dispersion medium and a non-halogenated hydrophilic non-volatile liquid, even if the object or the object has a member or part with static electricity in its vicinity, the object can be coated with a photocatalyst layer with good film-forming properties. This fact was made clear by experiments conducted by the present inventors.
Since the photocatalyst coating liquid of the present invention contains an aqueous dispersion medium, the risk of ignition or combustion during use can be reduced.

FIG. 1 is a schematic cross-sectional view of a photocatalytic spray according to one embodiment of the present invention.

The photocatalyst coating liquid of the present invention is characterized by containing photocatalyst fine particles, inorganic porous fine particles, a non-halogenated hydrophilic non-volatile liquid, and an aqueous dispersion medium.
The photocatalyst coating liquid preferably contains photocatalyst fine particles such that the ratio (a/b) of the mass a of the photocatalyst fine particles to the mass b of the inorganic porous fine particles is from 1 to 10. This allows the photocatalyst layer formed by coating the photocatalyst coating liquid to have both gas adsorption properties and photocatalytic activity.
The photocatalyst coating liquid preferably contains a hydrophilic nonvolatile liquid such that the ratio (n/m) of the mass n of the hydrophilic nonvolatile liquid to the total mass m of the mass a of the photocatalyst fine particles and the mass b of the inorganic porous fine particles is 0.5 to 2. This allows the photocatalyst layer to have excellent acetaldehyde gas decomposition activity and allows the photocatalyst layer to be formed into a film with good film-forming properties.

The hydrophilic non-volatile liquid preferably contains an aliphatic polyether derivative or a polyamine derivative, which can suppress the occurrence of film defects in the photocatalyst layer.
The material of the inorganic porous fine particles is preferably zeolite, silicon dioxide, silicate, activated carbon, titanium oxide, inorganic phosphate, alumina, aluminum hydroxide, or magnesium hydroxide.
The inorganic porous fine particles are preferably fine particles carrying a metal or a metal oxide, fine particles carrying a metal salt, or fine particles whose surface has been modified with an organic compound having a reactive functional group.

The photocatalyst fine particles are preferably tungsten oxide fine particles having an average particle size (D50) of 5 nm to 200 nm, which can improve the film-forming properties of the photocatalyst layer.
The tungsten oxide fine particles are preferably Pt-supported tungsten oxide fine particles, which can improve the photocatalytic activity of the photocatalytic layer.

The present invention also provides a photocatalyst spray comprising the photocatalyst coating liquid of the present invention and a spray container containing the photocatalyst coating liquid.
The present invention also provides a photocatalytic coating method comprising the step of applying the photocatalytic coating liquid of the present invention onto a substrate.
The present invention also provides a photocatalytic coating comprising a substrate and a photocatalytic layer provided on the substrate. The photocatalytic layer comprises photocatalytic fine particles, inorganic porous fine particles, and a non-halogenated hydrophilic non-volatile liquid.

The present invention will be described in more detail below with reference to several embodiments. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

First Embodiment The first embodiment relates to a photocatalyst coating liquid.
The photocatalyst coating liquid of this embodiment is characterized by containing photocatalyst fine particles, inorganic porous fine particles, a non-halogenated hydrophilic non-volatile liquid, and an aqueous dispersion medium.

[Photocatalytic coating liquid]
The photocatalyst coating liquid is a liquid for forming a photocatalyst layer on the surface of an object by a coating method.
This is a suspension in which photocatalyst fine particles and inorganic porous fine particles are dispersed in an aqueous dispersion medium. The photocatalyst coating liquid also includes a non-halogenated hydrophilic non-volatile liquid. The photocatalyst coating liquid may be a photocatalyst deodorant. The photocatalyst fine particles and inorganic porous fine particles contained in the photocatalyst coating liquid can be crushed and mixed in a wet process to make them easier to disperse in the aqueous dispersion medium.
The method for applying the photocatalyst coating liquid to the object is not particularly limited, but examples thereof include spray coating, dip coating, spin coating, bar coating, brush coating, roller brush coating, roll coater coating, curtain flow coater coating, and the like.

[Aqueous Dispersion Medium]
The aqueous dispersion medium is water or an aqueous solution, and is a medium in which the photocatalyst fine particles and the inorganic porous fine particles are dispersed. The aqueous dispersion medium is preferably, for example, an aqueous ethanol solution.
When the aqueous dispersion medium is an ethanol solution, the role of the ethanol is to reduce the viscosity of the spray droplets to maintain a fine spray state, to reduce the drying time of the spray droplets by adding ethanol to the solvent since it is more volatile than water, and to enable long-term storage of the photocatalyst coating solution since ethanol has a bactericidal effect.
The ethanol content in the ethanol aqueous solution (aqueous dispersion medium) is preferably 20 wt% or more and less than 60 wt%. If the amount of ethanol in the dispersion medium exceeds 60 wt%, it is not preferable because it becomes easy to burn or ignite and it becomes difficult to maintain the photocatalyst dispersion state during long-term storage. Also, if the amount of ethanol in the dispersion medium is less than 20 wt%, it is not preferable because the drying of the sprayed components becomes slow.

[Photocatalytic fine particles]
The photocatalyst fine particles (powder having a photocatalytic effect) contained in the photocatalyst coating liquid are powders or fine particles having photocatalytic activity. In a photocatalyst layer formed by applying the photocatalyst coating liquid to the surface of an object and drying it, when light having an energy equal to or greater than the energy gap between the valence band and the conduction band is irradiated onto the photocatalyst fine particles, electrons in the valence band of the photocatalyst fine particles are excited to the conduction band, holes are generated in the valence band, and these electrons and holes move inside the photocatalyst fine particles. The generated electrons reduce oxygen gas, generating superoxide anions. The holes oxidize water, generating hydroxyl radicals. The generated hydroxyl radicals generate active oxygen species. The generated active oxygen species achieves the decomposition of harmful substances that are the source of odors, for example.

Generally, titanium oxide and tungsten oxide are well known as photocatalyst fine particles, but in order to obtain a photocatalyst layer having excellent photocatalytic activity even under an indoor visible light source, the photocatalyst coating liquid preferably contains tungsten oxide. The photocatalyst coating liquid may contain only one type of photocatalyst fine particles, or may contain two or more types of photocatalyst fine particles.
The tungsten oxide contained in the photocatalyst coating liquid is not particularly limited, and commercially available products can be used as the tungsten oxide. Examples _of tungsten oxide include _WO3 (tungsten trioxide), _WO2 , _WO , _W2O3 , _W4O5 , _W4O11 , _W25O73 , _W20O58 , _{and W24O68} , as well as mixtures thereof. In order to improve the photocatalytic activity, _WO3 is preferred as _the tungsten oxide. A part of the tungsten oxide may be _reduced to a V-value. However, it is preferred that the tungsten oxide is _oxidized to a VI-value before use. Examples of the method of oxidation to a VI-value include a method of baking tungsten oxide at a high temperature. The crystal structure of the tungsten oxide is not particularly limited.

The average particle diameter of the photocatalyst fine particles is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less. When the average particle diameter of the photocatalyst fine particles is 5 nm or more, the photocatalyst fine particles are less likely to aggregate, and the photocatalyst fine particles are easily redispersed. When the average particle diameter of the photocatalyst fine particles is 200 nm or less, the photocatalyst fine particles tend to be uniformly mixed with other spray components, and the photocatalyst fine particles can be prevented from being detached from the photocatalyst layer formed by applying and drying the photocatalyst coating liquid. The average particle diameter of the photocatalyst fine particles is a value calculated based on the specific surface area (unit: ^m2 /g) of the photocatalyst fine particles measured by the BET method, assuming that the primary particles of the photocatalyst fine particles are spherical.

The surface of the photocatalyst fine particles may be provided with co-catalyst particles. As the co-catalyst particles, metal particles are preferred, transition metal particles are more preferred, and platinum group metal particles are even more preferred. Examples of platinum group metal particles include particles of Pt, Pd, Rh, Ru, Os, and Ir. By providing the co-catalyst particles on the surface of the photocatalyst fine particles, the energy gap between the valence band and the conduction band of the photocatalyst fine particles can be reduced, and the photoresponsiveness in the visible light region can be improved. The co-catalyst particles may be particles of an oxide of a platinum group metal.
The weight percentage of the photocatalyst fine particles in the photocatalyst coating liquid is preferably in the range of 0.1 wt % to 2.0 wt %. If the photocatalyst fine particles are less than 0.1 wt %, the deodorizing effect will be small, and if they exceed 2.0 wt %, the photocatalyst fine particles will tend to aggregate, which is not preferable.

[Inorganic porous particles]
The inorganic porous fine particles are inorganic porous powders having a gas adsorption effect. Examples of inorganic porous fine particles include zeolite, silicon dioxide, silicate, activated carbon, titania, inorganic phosphate such as calcium phosphate, alumina, etc. The inorganic porous fine particles are surface-modified with an organic compound having a reactive functional group that chemically reacts with and bonds to odorous substances. The inorganic porous particles may be white, colorless, or colored. It's okay if there is.
In the photocatalyst coating liquid, the ratio (b/a) of the mass b of the inorganic porous fine particles to the mass a of the photocatalyst fine particles is not particularly limited, but is preferably 0.1 or more and 1.0 or less. In this case, the photocatalytic activity of the photocatalyst layer formed by applying the photocatalyst coating liquid can be increased, and the deodorizing effect of the photocatalyst layer can be improved.

The inorganic porous fine particles may be those whose surfaces are modified with an organic compound, and the organic compound may have a reactive functional group that chemically reacts with and bonds to odorous substances.
An example of the reactive functional group is an amino group ( _-NH2 , -NHR, -NRR'). In this case, a compound having an amino group (amine) is modified on the surface of the inorganic porous microparticles. The compound having an amino group is not particularly limited as long as it has one or more amino groups in the molecule, and examples of the compound include aliphatic amines, aromatic amines, and alicyclic amines. The amino group is a reactive functional group that is effective in chemically adsorbing malodors of aldehydes such as acetaldehyde.
Examples of inorganic porous microparticles having amino groups on the surface include KESMON (registered trademark) manufactured by Toagosei Co., Ltd. (KESMON NS-103, KESMON NS-750, KESMON NS-231, KESMON NS-240, KESMON KS-210, KESMON KS-730), and KIRAKURU (registered trademark) manufactured by NICCA CHEMICAL CO., LTD. (KIRAKURU AL-07).

The inorganic porous microparticles may have a metal, a metal oxide, or a metal salt supported on the surface thereof. The metal or metal oxide may be copper, zinc, manganese, silver, or an oxide thereof. These metals or metal oxides are effective in removing malodors such as ammonia, trimethylamine, and methyl mercaptan.
Examples of inorganic porous microparticles carrying a metal, metal oxide or metal salt include Shucleanz (registered trademark) manufactured by Rasa Kogyo Co., Ltd. and Sumerclean (registered trademark) manufactured by Fuji Chemical Co., Ltd.

The inorganic porous fine particles may be fine particles that physically adsorb gas. For example, the inorganic porous fine particles may be zeolite, which is a material that is effective for physically adsorbing malodors of aldehydes such as acetaldehyde, and in particular, high-silica zeolite, which has a high ratio of silicon oxide in zeolite, is preferable. High-silica zeolite is hydrophobic, loses affinity for polar substances such as water, and can more strongly adsorb non-polar substances such as odor components. Examples of inorganic porous particles that physically adsorb gas include HSZ-690HOA (manufactured by Tosoh Corporation, mordenite type, silica/alumina ratio: 240, average particle size: 13 μm, cationic type: H, specific surface area (BET): 450 m ² /g), HSZ-890HOA (manufactured by Tosoh Corporation, ZSM-5 type, silica/alumina ratio: 1500, average particle size: 10 μm, cationic type: H, specific surface area (BET): 310 m ^{2 /g), and HSZ-891HOA (manufactured by Tosoh Corporation, ZSM-5 type, silica/alumina ratio: 1500, average particle size: 4 μm, cationic type: H, specific surface area (BET): 310 m 2 /} g). /g), HiSiv(TM)-3000 (manufactured by Union Showa Co., Ltd., average particle size: 3 μm, cation type: Na, pore size: 6 Å or less, specific surface area (BET): 400 m ² /g), Silton MT100 (manufactured by Mizusawa Chemical Industry Co., Ltd., silica/alumina ratio: 100, average particle size 3 to 4.5 μm, specific surface area (BET): 360 m ² /g), and Silton MT-8000 (manufactured by Mizusawa Chemical Industry Co., Ltd., silica/alumina ratio: 8000, average particle size 0.8 μm, specific surface area (BET): 390 m ² /g).
The inorganic porous microparticles (inorganic porous material) can be appropriately selected to have any average particle size by crushing, but the average particle size is preferably 0.01 μm to 10 μm. The specific surface area (BET) of the inorganic porous microparticles is not particularly limited, but is preferably 200 m ² /g or more, more preferably 400 m ² /g or more. The upper limit of the specific surface area is not particularly limited, but is, for example, 1000 m ² /g or less.

[Non-halogenated hydrophilic non-volatile liquid]
The non-halogenated hydrophilic non-volatile liquid is a compound that is in a liquid state at room temperature and does not contain fluorine, chlorine, bromine, iodine, or astatine. Furthermore, the non-halogenated hydrophilic non-volatile liquid is a compound that is hydrophilic and non-volatile. By containing a non-halogenated hydrophilic non-volatile liquid in the photocatalyst coating liquid, the dispersibility of the photocatalyst fine particles and the inorganic porous fine particles can be maintained, and the droplets containing these particles can be prevented from instantly evaporating after spraying. This makes the spray droplets less susceptible to partial charging of the spray target or charging in the vicinity thereof, and prevents uneven coating of the layer consisting of the photocatalyst fine particles and the inorganic porous fine particles.

The hydrophilic non-volatile liquid contained in the photocatalyst coating liquid has the effect of wetting the surfaces of the photocatalyst fine particles and the inorganic porous fine particles, and dispersing these materials well in the photocatalyst coating liquid. In addition, the hydrophilic non-volatile liquid has the effect of preventing the droplets of the photocatalyst coating liquid after spraying from drying, causing large aggregates of these fine particles to adhere and adhere to the surroundings in a more dispersible manner. In addition, the hydrophilic non-volatile liquid can prevent the spray droplets of the photocatalyst coating liquid from being charged. Furthermore, it is preferable that the hydrophilic non-volatile liquid is a non-halogen-based composition that is easily decomposed by irradiating the photocatalyst with light and is safe.
Examples of hydrophilic non-volatile liquids that have such an effect include aliphatic polyether derivatives and aliphatic amine derivatives.

The details of the mechanism by which such effects are manifested are unknown, but the following is presumed. The polyether portion of the aliphatic polyether derivative is adsorbed to the surface of the photocatalyst fine particles and the surface of the inorganic porous fine particles in the dispersion medium, improving the wettability of the fine particles and the dispersion medium, and since it remains adsorbed to the fine particle surface even after the photocatalyst coating liquid is sprayed, the effect of droplets containing these particles not instantly agglomerating is obtained. The amino group of the aliphatic amine derivative is adsorbed to the hydrophilic group of the photocatalyst fine particles, improving the wettability of the powder particles and the dispersion medium, and further maintaining the barrier effect of the alkylene group, suppressing the aggregation of particles. Since it remains adsorbed to the powder particle surface even after the photocatalyst coating liquid is sprayed, the effect of droplets containing the powder particles not instantly agglomerating is obtained. However, these are presumed, and the present invention is not limited to these mechanisms.

The alkylene group of the aliphatic polyether derivative contained in the photocatalyst coating liquid is preferably an ethylene group and/or a propylene oxide group. Specific examples of the aliphatic polyether derivative include polyethylene glycol, polypropylene glycol, and poly(ethylene/propylene) glycol. The molecular weight of the derivative is a low degree of polymerization in the range of about 200 to 10,000.

The aliphatic amine derivative contained in the photocatalyst coating liquid is preferably a polyoxyethylene alkylamine or an alkylamine, and specific examples thereof include polyoxyethylene laurylamine (polyoxyethylene coconut alkylamine), polyoxyethylene (2) hydrogenated beef tallow amine, polyoxyethylene (20) hydrogenated beef tallow amine, monoethanolamine, diethanolamine, and triethanolamine.
The ratio (n/m) of the weight n of the non-halogenated hydrophilic non-volatile liquid contained in the photocatalyst coating liquid to the total weight m of the photocatalyst fine particles and inorganic porous fine particles contained in the photocatalyst coating liquid is preferably 0.5 to 2. If the weight ratio of the non-halogenated hydrophilic non-volatile liquid is less than 0.5, the effect becomes small, and even if the ratio exceeds 2, the effect is the same, which is not preferable.

It is preferable that the non-halogenated hydrophilic non-volatile liquid is in a liquid state at 25°C. If it is not liquid at room temperature, the non-halogenated hydrophilic non-volatile liquid will solidify in the photocatalyst coating liquid or after the photocatalyst coating liquid is sprayed, causing poor dispersion of the photocatalyst fine particles and inorganic porous fine particles, resulting in uneven application of the components and preventing the original deodorizing effect from being achieved.

[Additives]
The additives that may be contained in the photocatalyst coating liquid include organic compounds and inorganic compounds having antiseptic effects.The organic compounds having antiseptic effects include paraoxybenzoic acid esters such as butylparaben, propylparaben, ethylparaben, methylparaben, benzylparaben, isopropylparaben, and isobutylparaben, organic nitrogen sulfur compounds, pyrithione compounds, organic iodine compounds, triazine compounds, isothiazolinone compounds, imidazole compounds, pyridine compounds, nitrile compounds, thiocarbamate compounds, thiazole compounds, and disulfide compounds.The inorganic compounds having antiseptic effects include metal ion-containing inorganic compounds.

Second Embodiment The second embodiment relates to a photocatalyst spray.
FIG. 1 is a schematic cross-sectional view of the photocatalyst spray of this embodiment.
The photocatalyst spray 20 includes the photocatalyst coating liquid 2 of the first embodiment and a spray container 3 that contains the photocatalyst coating liquid 2 .

[Photocatalytic spray]
The photocatalyst spray 20 may be a trigger spray bottle containing the photocatalyst coating liquid 2, an aerosol spray using liquefied gas (propellant), a pressurized spray, or an electric spray. An aerosol spray is illustrated in FIG. 1, and the aerosol spray will be taken as an example for explanation.
The photocatalyst spray 20 is a product that releases the photocatalyst coating liquid 2 inside the aerosol container 3 to the outside of the aerosol container 3 by the pressure of the propellant. When the photocatalyst coating liquid 2 is released toward an object using the photocatalyst spray 20, a photocatalyst layer containing photocatalyst fine particles and inorganic porous fine particles is formed on the surface of the object, and the object can be evenly coated with the photocatalyst layer.

[Aerosol container]
The aerosol container 3 is a container for an aerosol product, and includes a pressure-resistant container 9 that contains the photocatalyst coating liquid 2 and a propellant, a valve member 5, an actuator 4, a tube 6, etc. The valve member 5 can include a stem, a stem hole, a stem gasket, etc.
When the head of the actuator 4 is not pressed, the stem gasket closes the stem hole, and the inside of the aerosol container 3 is sealed.
When the head of the actuator 4 is pressed, the stem and the stem gasket move down, opening the stem hole and connecting the flow path of the photocatalyst coating liquid 2 to the injection hole 7. The inside of the aerosol container 3 is under high pressure due to the propellant, and this pressure causes the photocatalyst coating liquid 2 to flow through the flow path of the tube 6, the valve member 5 and the actuator 4 and be sprayed out from the injection hole 7.

[Propellant]
The propellant contains dimethyl ether, and is a component for creating high pressure inside the aerosol container 3. The boiling point of dimethyl ether is −24.8° C., and since dimethyl ether is placed in the aerosol container 3 as a liquefied gas, inside the aerosol container 3, a portion of the dimethyl ether is dissolved in the photocatalyst coating liquid 2 or exists as a liquid, and a portion of the dimethyl ether exists as a gas in the gas phase 8. In addition, an amount of propellant is placed in the aerosol container 3 such that the internal pressure of the aerosol container 3 is 0.33 MPa or more at 25° C.

[Method of manufacturing photocatalyst spray]
Here, an aerosol spray will be taken as an example of the photocatalyst spray 20 for explanation.
The aerosol spray can be manufactured by a normal aerosol spray manufacturing method. The aerosol container 3 is a cylindrical container with a bottom made of aluminum or tinplate, and is filled with the photocatalyst coating liquid 2, and then the aerosol bubble is clinched at the opening at the top end via a gasket, and a propellant such as liquefied gas is filled to a predetermined liquid amount. As the liquefied gas, propane (liquid density: 0.501 g/ml), normal butane (liquid density: 0.579 g/ml), isobutane (liquid density: 0.557 g/ml), and mixtures thereof such as liquefied petroleum gas, dimethyl ether (liquid density: 0.661 g/ml), and mixed gas of liquefied petroleum gas and dimethyl ether are used because the liquid density of the liquefied gas is easy to adjust and the pressure of the aerosol is easy to adjust. In addition, compressed gas such as carbon dioxide gas, nitrogen gas, compressed air, and oxygen gas can be used as a pressurizing agent to adjust the internal pressure of the aerosol container 3. The internal pressure of the photocatalyst spray 20 is preferably 0.35 MPa or more and 0.50 MPa or less at a temperature of 25° C. The internal pressure decreases when the temperature is low and increases when the temperature is high. When the temperature is low, the internal pressure decreases, the sprayability becomes poor, and it becomes difficult to uniformly attach and fix the ingredients to the surroundings.
Moreover, the description of the photocatalyst coating liquid of the first embodiment also applies to the photocatalyst coating liquid 2 contained in the photocatalyst spray 20 of the second embodiment, unless there is a contradiction.

Third Embodiment The third embodiment relates to a deodorizing method using the photocatalyst spray 20 of the second embodiment.
The photocatalyst coating liquid 2 is sprayed from the photocatalyst sprayer 20 of the second embodiment toward an object (substrate) in a room, and a photocatalyst layer containing photocatalyst fine particles and inorganic porous fine particles is formed on the surface of the object. The photocatalyst layer immediately after formation contains a non-halogen-based hydrophilic non-volatile liquid. The object (substrate) coated with this photocatalyst layer is a photocatalyst-coated object. For example, when the photocatalyst coating liquid 2 is sprayed from the photocatalyst sprayer 20 in a room, the photocatalyst coating liquid 2 or its dried product adheres to the components in the room, such as glass, plastic, metal, ceramics, wood, stone, cement, concrete, fiber, fabric, paper, and leather. When the photocatalyst coating liquid 2 or its dried product is continuously sprayed in the room, a known full-amount spray button can be used as the spray button. The thickness of the photocatalyst layer containing photocatalyst fine particles and inorganic porous fine particles formed after spraying is not particularly limited.

When the photocatalyst layer is irradiated with light from a lighting device or natural light, the photocatalytic activity of the photocatalyst fine particles is activated, and the odorous components present in the room are decomposed. In addition, since the photocatalyst layer contains inorganic porous fine particles, the photocatalyst layer adsorbs odorous components present in the room. The odorous components adsorbed by the inorganic porous fine particles are decomposed by the photocatalytic activity of the photocatalyst fine particles. Therefore, this photocatalyst layer has a high deodorizing effect.
The non-halogenated hydrophilic non-volatile liquid contained in the photocatalyst layer is decomposed by the photocatalytic activity of the photocatalyst fine particles.

Experiments on the Preparation of Photocatalyst Sprays Photocatalyst sprays according to Examples 1 to 28 and a photocatalyst spray according to Comparative Example 1 were prepared. Table 1 shows the composition of the photocatalyst coating liquid contained in each photocatalyst spray.

"Pt--WO ₃ " in Table 1 represents platinum-supported tungsten oxide particles. The platinum-supported tungsten oxide particles, which are photocatalytic fine particles, were prepared by the method described below.
200 g of tungsten oxide powder (Kishida Chemical Co., Ltd.) was mixed with 1000 mL of pure water, and then dispersed while irradiating ultrasonic waves to obtain a dispersion liquid A of tungsten oxide particles. Hexachloroplatinum (VI) hexahydrate (Kishida Chemical Co., Ltd., purity 98.5%) was dissolved in the dispersion liquid A to obtain a dispersion liquid B of tungsten oxide particles. The amount of hexachloroplatinum (VI) hexahydrate added was such that the ratio of the weight of platinum alone to the weight of the tungsten oxide particles was 0.05 wt%. Dispersion liquid B was heated at 100°C to evaporate the water, and then baked at 500°C to obtain a platinum-supported tungsten oxide powder. The average particle size of the platinum-supported tungsten oxide particles contained in the obtained powder was 175 nm.

The "hydrophilic non-volatile liquid" shown in Table 1 was polyethylene glycol: PEG200 manufactured by Toho Chemical Industry Co., Ltd., which is an aliphatic polyether derivative, or polymeric amine: Sreem AD-3172M manufactured by NOF Corporation. "Water" in Table 1 is pure water, and "EtOH" is ethyl alcohol. "-" in Table 1 indicates that the photocatalyst coating liquid does not contain the corresponding material. "Solid content" in Table 1 indicates "the sum of the mass of Pt-WO ₃ and the mass of inorganic porous powder in the dispersion liquid.""Hydrophilic non-volatile liquid (g)/Solid content of dispersion liquid (g)" indicates "the ratio of the mass of hydrophilic non-volatile liquid to the sum of the mass of Pt-WO ₃ and the mass of inorganic porous powder in the dispersion liquid.""Ethanolwt%" indicates "the weight percentage of ethanol in the photocatalyst coating liquid."
Hereinafter, a method for producing the photocatalyst sprays of Examples 1 to 28 and Comparative Example 1 shown in Table 1 will be described. In addition, the sample numbers of the photocatalyst sprays shown in Table 1 will be used for the explanation.

<Preparation of photocatalyst spray>
[Preparation of Dispersion of Pt- _WO3 and Inorganic Porous Powder]
First, dispersions (1) to (6) of Pt- _WO3 and inorganic porous powder (inorganic porous fine particles) used in the production of photocatalyst sprays were prepared.
The photocatalytic fine particles used were prepared Pt--WO ₃ (platinum-supported tungsten oxide particles).
As the inorganic porous powder, zeolite powder (HSZ-891HOA crushed by a bead mill, D50v 0.5 μm) or amino group-supported silicon dioxide (Kesmon KS-730 D50v 0.02 μm) was used.

The prepared Pt- _WO3 and inorganic porous powder were mixed with pure water so that the solid concentration of the dispersion was 20 wt%. The mixture was dispersed while being irradiated with ultrasonic waves to prepare 100 g of each of dispersions (1) to (6). The mixing ratios of dispersions (1) to (6) were as follows:
Dispersion liquid (1): Platinum-supported tungsten oxide particles: Zeolite: Pure water
=18.2:1.82:80.0
Dispersion liquid (2): Platinum-supported tungsten oxide particles: zeolite: pure water
= 10:10:80
Dispersion liquid (3): Platinum-supported tungsten oxide particles: amino group-supported silicon dioxide: pure water
=18.2:1.82:80.0
Dispersion liquid (4): Platinum-supported tungsten oxide particles: amino group-supported silicon dioxide: pure water
= 10:10:80
Dispersion liquid (5): platinum-supported tungsten oxide particles: zeolite: pure water
=19.0:1.0:80
Dispersion liquid (6): Platinum-supported tungsten oxide particles: zeolite: pure water
=6.7:13.3:80
In Table 1, in examples or comparative examples using dispersion liquid (1) and dispersion liquid (3), the ratio (b/a) of the mass b of the inorganic porous microparticles to the mass a of the photocatalyst microparticles is 0.1, in examples using dispersion liquid (2) and dispersion liquid (4), the ratio (b/a) of the mass b of the inorganic porous microparticles to the mass a of the photocatalyst microparticles is 1.0, in examples using dispersion liquid (5), the ratio (b/a) of the mass b of the inorganic porous microparticles to the mass a of the photocatalyst microparticles is 0.05, and in examples using dispersion liquid (6), the ratio (b/a) of the mass b of the inorganic porous microparticles to the mass a of the photocatalyst microparticles is 1.99.

Next, the photocatalyst coating liquid was prepared using the method described below, and filled into an aluminum aerosol container to produce each photocatalyst spray.

[Preparation of photocatalyst spray (A-(1)-1)]
39.5 g of water, 10.0 g of ethanol, and 0.05 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 0.5 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(1)-1).

[Preparation of photocatalyst spray (A-(1)-2)]
15.5 g of water, 29.0 g of ethanol, and 0.5 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(1)-2).

[Preparation of photocatalyst spray (A-(1)-3)]
39.3 g of water, 10.0 g of ethanol, and 0.20 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 0.5 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(1)-3).

[Preparation of photocatalyst spray (A-(1)-4)]
14.0 g of water, 29.0 g of ethanol, and 2.00 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 5.0 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(1)-4).

[Preparation of photocatalyst spray (A-(2)-1)]
39.5 g of water, 10.0 g of ethanol, and 0.05 g of hydrophilic non-volatile liquid polyethylene glycol PEG200 were mixed and stirred, and then 0.5 g of the dispersion liquid (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(2)-1).

[Preparation of photocatalyst spray (A-(2)-2)]
15.5 g of water, 29.0 g of ethanol, and 0.5 g of hydrophilic non-volatile liquid polyethylene glycol PEG200 were mixed and stirred, and then 5.0 g of the dispersion liquid (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(2)-2).

[Preparation of photocatalyst spray (A-(2)-3)]
39.3 g of water, 10.0 g of ethanol, and 0.20 g of hydrophilic non-volatile liquid polyethylene glycol PEG200 were added and stirred, and then 0.5 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(2)-3).

[Preparation of photocatalyst spray (A-(2)-4)]
14.0 g of water, 29.0 g of ethanol, and 2.00 g of hydrophilic non-volatile liquid polyethylene glycol PEG200 were added and stirred, and then 5.0 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(2)-4).

[Preparation of photocatalyst spray (A-(3)-1)]
39.5 g of water, 10.0 g of ethanol, and 0.05 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 0.5 g of the dispersion (2) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(3)-1).

[Preparation of photocatalyst spray (A-(3)-2)]
15.5 g of water, 29.0 g of ethanol, and 0.5 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (2) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(3)-2).

[Preparation of photocatalyst spray (A-(3)-3)]
39.3 g of water, 10.0 g of ethanol, and 0.20 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 0.5 g of the dispersion (2) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(3)-3).

[Preparation of photocatalyst spray (A-(3)-4)]
14.0 g of water, 29.0 g of ethanol, and 2.00 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 5.0 g of the dispersion (2) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(3)-4).

[Preparation of photocatalyst spray (A-(4)-1)]
39.5 g of water, 10.0 g of ethanol, and 0.05 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 0.5 g of the dispersion (3) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(4)-1).

[Preparation of photocatalyst spray (A-(4)-2)]
15.5 g of water, 29.0 g of ethanol, and 0.5 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (3) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(4)-2).

[Preparation of photocatalyst spray (A-(4)-3)]
39.3 g of water, 10.0 g of ethanol, and 0.20 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 0.5 g of the dispersion (3) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(4)-3).

[Preparation of photocatalyst spray (A-(4)-4)]
14.0 g of water, 29.0 g of ethanol, and 2.00 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 5.0 g of the dispersion (3) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(4)-4).

[Preparation of photocatalyst spray (A-(5)-1)]
39.5 g of water, 10.0 g of ethanol, and 0.05 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 0.5 g of the dispersion (4) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(5)-1).

[Preparation of photocatalyst spray (A-(5)-2)]
15.5 g of water, 29.0 g of ethanol, and 0.5 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (4) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(5)-2).

[Preparation of photocatalyst spray (A-(5)-3)]
39.3 g of water, 10.0 g of ethanol, and 0.20 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 0.5 g of the dispersion (4) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as the active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(5)-3).

[Preparation of photocatalyst spray (A-(5)-4)]
14.0 g of water, 29.0 g of ethanol, and 2.00 g of the hydrophilic non-volatile liquid S-ream AD-3172M were added and stirred, and then 5.0 g of the dispersion (4) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating solution as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (A-(5)-4).

[Preparation of photocatalyst spray (B-1)]
35.2 g of water and 9.8 g of ethanol were mixed and stirred, and then 5.0 g of a 20 wt % dispersion of platinum-supported tungsten oxide particles:pure water=20:80 was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was used, and the above photocatalyst coating liquid was filled as an active ingredient and 50 g of dimethyl ether was filled as a propellant (liquefied gas) into the aerosol container to obtain a photocatalyst spray (B-1). The photocatalyst spray (B-1) did not contain a hydrophilic non-volatile liquid.

[Preparation of photocatalyst spray (B-2)]
34.9 g of water, 9.7 g of ethanol, and 0.4 g of the hydrophilic non-volatile liquid PEG 200 were mixed and stirred, and then 5.0 g of the dispersion liquid (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-2).

[Preparation of photocatalyst spray (B-3)]
34.9 g of water, 9.7 g of ethanol, and 0.4 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-3).

[Preparation of photocatalyst spray (B-4)]
32.0 g of water, 10.0 g of ethanol, and 3.0 g of the hydrophilic non-volatile liquid PEG 200 were mixed and stirred, and then 5.0 g of the dispersion liquid (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-4).

[Preparation of photocatalyst spray (B-5)]
32.0 g of water, 10.0 g of ethanol, and 3.0 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (1) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-5).

[Preparation of photocatalyst spray (B-6)]
34.5 g of water, 10.0 g of ethanol, and 0.50 g of the hydrophilic non-volatile liquid PEG200 were mixed and stirred, and then 5.0 g of the dispersion (5) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-6).

[Preparation of photocatalyst spray (B-7)]
34.5 g of water, 10.0 g of ethanol, and 0.50 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (5) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-7).

[Preparation of photocatalyst spray (B-8)]
34.5 g of water, 10.0 g of ethanol, and 0.50 g of the hydrophilic non-volatile liquid PEG200 were mixed and stirred, and then 5.0 g of the dispersion (6) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-8).

[Preparation of photocatalyst spray (B-9)]
34.5 g of water, 10.0 g of ethanol, and 0.50 g of the hydrophilic non-volatile liquid S-ream AD-3172M were mixed and stirred, and then 5.0 g of the dispersion (6) prepared above was added to obtain a photocatalyst coating liquid.
An aluminum aerosol container (full capacity 200 ml) was filled with the above photocatalyst coating liquid as an active ingredient and 50 g of dimethyl ether as a propellant (liquefied gas) to obtain a photocatalyst spray (B-9).

Evaluation of photocatalyst spray <Evaluation method and results of photocatalyst spray>
[Check for defects in coating film]
The coating film was inspected for defects using the method described below.
A room was prepared with a volume of 3.6 ^m3 (indoor length x indoor width x indoor height).
A polycarbonate sheet (thickness 0.5 mm, diameter 50 mm) was rubbed with a cloth or the like, and the surface of the polycarbonate sheet was charged to +10 kV while measuring with a static electricity meter, and then the sheet was placed at the front of the chamber (front half of the longitudinal direction of the space).
One of the photocatalyst sprays (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), (B-1) to (B-9) was placed on the floor in the center of the room, and the full amount spray button was pressed and locked at the installed position, spraying began, and the door of the room was closed. After spraying was completed, the room was left in that state for 5 minutes to allow the ingredients to settle.

The door of the chamber was opened, the polycarbonate sheet was taken out, and the coating film (photocatalyst layer) formed on the surface of the polycarbonate sheet was observed from directly above to confirm the presence or absence of defects in the coating film. The coating film defects referred to here refer to a phenomenon in which, when the photocatalyst coating liquid is sprayed from the photocatalyst sprayer, Pt- _WO3 or inorganic porous fine particles contained in the photocatalyst coating liquid are charged and collected on the substrate surface (polycarbonate sheet surface), and further, the Pt- _WO3 or inorganic porous fine particles are aggregated, making the coating surface look white as if it were covered with mist. If the coating film had no defects, it was evaluated as "good ○", if the coating film had some defects, it was evaluated as "slightly poor △", and if the coating film had defects in the entirety of the coating film, it was evaluated as "poor ×". The evaluation results are shown in Table 2.

[Injectability test]
After checking for defects in the coatings as described above, the state of splashing of photocatalyst coating liquid around the locations where each of the photocatalyst spray cans (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), and (B-1) to (B-9) was installed was confirmed and judged.
The results are shown in Table 2. In the evaluation in Table 2, "good" indicates that no droplets were scattered around.

[Preparation of samples for light irradiation test and dark test]
The photocatalyst coating solution from each photocatalyst spray (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), (B-1) to (B-9) was sprayed onto a cellulose fabric (125 mm x 125 mm) for 20 seconds. By drying the cellulose fabric, test samples (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), and (B-1) to (B-9) were prepared, each having a photocatalyst layer formed on the cellulose fabric. These test samples were then left to dry in a sunny location for one week.

[Light irradiation test]
A gas bag with a volume of 1 L was prepared for each test sample, and test samples (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), and (B-1) to (B-9) were placed into each of these gas bags, and then acetaldehyde gas was added to the gas bag to achieve a concentration of 20 ppm.
A blue LED (peak wavelength 450 nm) lamp was used to irradiate the test sample with 4,500 lux of light, and the acetaldehyde gas concentration in the gas bag 12 hours after the gas was added was measured with a detector tube. Note that acetaldehyde gas is a malodorous substance, and the light irradiation test is a deodorization test that removes acetaldehyde gas by the photocatalytic activity of the photocatalyst fine particles and the adsorption effect of the inorganic porous powder.
The test results of each test sample are shown in Table 2. In Table 2, the evaluations are as follows: "Good ○" indicates that the acetaldehyde gas residual rate is less than 20%, "Slightly poor △" indicates that the acetaldehyde gas concentration is 20% or more and less than 50%, and "Poor ×" indicates that the acetaldehyde gas concentration is 50% or more and 100% or less.

[Dark place test]
A 1L gas bag was prepared for each sample, and test samples (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), (A-(5)-1) to (A-(5)-4), and (B-1) to (B-9) were placed into each of these gas bags, and then acetaldehyde gas was added to the gas bag to achieve a concentration of 5 ppm.
The gas bag after the gas introduction was left to stand in a dark place for 12 hours. The acetaldehyde gas concentration in the gas bag after standing was measured using a detector tube. Note that acetaldehyde gas is a malodorous substance, and the dark test is a deodorization test in which acetaldehyde gas is removed by the adsorption effect of inorganic porous powder.
The test results of each test sample are shown in Table 2. In Table 2, the evaluations are as follows: "Good ○" indicates that the acetaldehyde gas residual rate is less than 20%, "Slightly poor △" indicates that the acetaldehyde gas concentration is 20% or more and less than 50%, and "Poor ×" indicates that the acetaldehyde gas concentration is 50% or more and 100% or less.

In the overall evaluation in Table 2, if there was no rating of slightly poor △ or poor × in the coating defect confirmation test, sprayability test, light irradiation test, or dark test, it was rated as "good ○", if there was at least one rating of slightly poor △ in the coating defect confirmation test, sprayability test, light irradiation test, or dark test, it was rated as "slightly poor △", and if there was at least one rating of poor × in the coating defect confirmation test, sprayability test, light irradiation test, or dark test, it was rated as "poor ×".

In the photocatalyst sprays (A-(1)-1) to (A-(1)-4), (A-(2)-1) to (A-(2)-4), (A-(3)-1) to (A-(3)-4), (A-(4)-1) to (A-(4)-4), and (A-(5)-1) to (A-(5)-4) in which the ratio (n/m) of the weight n of the non-halogenated hydrophilic non-volatile liquid contained in the photocatalyst coating liquid to the weight m of the solids contained in the photocatalyst coating liquid is between 0.5 and 2 (see Table 1), no coating defects occurred, as shown in Table 2, and the acetaldehyde gas decomposition tests (light irradiation test and dark place test) were also favorable.
The photocatalyst sprays (B-2) and (B-3) showed slightly inferior film-forming properties. This is believed to be due to the small amount of hydrophilic non-volatile liquid contained in the photocatalyst coating solution.
The photocatalyst sprays (B-4) and (B-5) performed poorly in both the light irradiation test and the dark test. This is thought to be because there was too much hydrophilic non-volatile liquid, which caused the photocatalyst particles and inorganic porous particles to be buried in the hydrophilic non-volatile liquid, resulting in slightly poor acetaldehyde gas decomposition activity.
The results of the photocatalyst sprays (B-6) and (B-7) in the dark test were somewhat poor. This is thought to be due to the small amount of inorganic porous particles.
In the case of the photocatalyst spray (B-1) containing a photocatalyst coating liquid that does not contain a hydrophilic non-volatile liquid (see Table 1), defects occurred in the coating film as shown in Table 2, and the overall evaluation was "poor x".

2: Photocatalyst coating liquid 3: Aerosol container 4: Actuator 5: Valve member 6: Tube 7: Injection hole 8: Gas phase 9: Pressure-resistant container 20: Deodorizing spray

Claims (2)

The present invention includes a photocatalyst coating liquid, a propellant, and an aerosol container that contains the photocatalyst coating liquid and the propellant,
The photocatalyst coating liquid contains photocatalyst fine particles, inorganic porous fine particles, a non-halogenated hydrophilic non-volatile liquid, and an aqueous dispersion medium;
The photocatalytic fine particles are Pt-supported tungsten oxide fine particles,
the material of the inorganic porous fine particles is zeolite or amino group-supported silicon dioxide;
the aqueous dispersion medium is an aqueous ethanol solution,
The propellant comprises dimethyl ether,
the photocatalyst coating liquid contains the photocatalyst fine particles such that a ratio (b/a) of a mass b of the inorganic porous fine particles to a mass a of the photocatalyst fine particles is 0.1 or more and 1.0 or less;
the photocatalyst coating liquid contains the hydrophilic nonvolatile liquid such that a ratio (n/m) of a mass n of the hydrophilic nonvolatile liquid to a total mass m of a mass a of the photocatalyst fine particles and a mass b of the inorganic porous fine particles is 0.5 or more and 2 or less,
A photocatalyst spray, characterized in that the hydrophilic non-volatile liquid contains an aliphatic polyether derivative or a polyamine derivative. A photocatalytic coating method comprising the step of spraying the photocatalytic coating liquid contained in the photocatalytic spray according to claim 1 onto a substrate.