JPWO2013191162A1 - Photocatalyst coating material, article and method for producing photocatalyst coating material - Google Patents

Abstract

Provided are a photocatalyst coating material capable of enhancing adhesion between an aluminum material as a substrate and a photocatalyst layer, an article provided with the photocatalyst coating material, and a method for producing the photocatalyst coating material. The photocatalyst coating material includes an aluminum material, a photocatalyst layer containing metal oxide particles having photocatalytic activity formed on the surface of the aluminum material, and an aluminum formed between the aluminum material and the photocatalyst layer. And an intervening layer containing carbon. A photocatalyst layer containing metal oxide particles having photocatalytic activity is formed on the surface of an aluminum material, and heating is performed with the aluminum material having the photocatalyst layer formed in a space containing a hydrocarbon-containing substance. Thus, a photocatalyst coating material is manufactured.

Description

  The present invention relates to a photocatalyst coating material, an article provided with the photocatalyst coating material, and a method for producing the photocatalyst coating material.

  When a semiconductor is irradiated with light having energy higher than the band gap, an organic substance such as a resin that contacts the surface of the semiconductor is decomposed by a strong redox action. Utilizing the photocatalytic activity of this semiconductor for various environmental purifications, such as decomposition or detoxification of harmful substances in the atmosphere, water, etc., deodorization of living space, prevention of solid surface contamination in living space, antibacterial activity in living space, etc. The development of technology is underway. Examples of semiconductor photocatalysts used for such purposes include metal oxides such as titanium oxide, zinc oxide, zirconium oxide, and tungsten oxide. In addition, since the semiconductor surface is utilized when actually used for environmental purification, the above metal oxide particles are formed on the surface of the substrate in the form of a film, a layer or the like for the purpose of enhancing the photocatalytic activity. It is often used by immobilizing and increasing the surface area for photocatalytic reaction.

  As a method for immobilizing titanium oxide particles that are most frequently used as a semiconductor photocatalyst, for example, JP-A-6-293519 (hereinafter referred to as Patent Document 1) uses a suspension of titanium oxide particles as a support. And a method of producing a titanium oxide film by fixing the titanium oxide particles on a support by baking.

  Also, for example, JP-A-7-316342 (hereinafter referred to as Patent Document 2) describes a laminate comprising a synthetic resin composition layer obtained by incorporating titanium oxide particles as a photocatalyst into a synthetic resin. Has been.

JP-A-6-293519 JP-A-7-316342

  However, in the method described in Patent Document 1, it is necessary to increase the thickness of the titanium oxide film in order to increase the surface area for photocatalytic reaction. When the thickness of the titanium oxide film is increased, the adhesion between the titanium oxide particles and the support is lowered. Further, if the firing temperature is increased in order to promote the fixation of the titanium oxide particles to the support, it is difficult to use a material that softens at a relatively low temperature, such as an aluminum material, as the support material.

  Further, as in the laminate described in Patent Document 2, when an organic material such as a synthetic resin is used as a binder and titanium oxide particles as a photocatalyst are to be immobilized, the organic binder itself is the titanium oxide particle. Deteriorated by photocatalysis. For this reason, there exists a problem that the adhesiveness between titanium oxide particles falls. Although not described in Patent Document 2, when an organic material such as a synthetic resin is used as a binder and titanium oxide particles as a photocatalyst are to be immobilized on a substrate, oxidation is performed in the same manner as described above. There exists a problem that the adhesiveness between a titanium particle and a base material falls.

  Accordingly, an object of the present invention is to solve the above-described problem, and includes a photocatalyst coating material capable of improving adhesion between an aluminum material as a base material and a photocatalyst layer, and the photocatalyst coating material. And a method for producing the photocatalyst coating material.

  As a result of intensive studies to solve the problems of the prior art, the present inventor achieves the above object by heating an aluminum material provided with metal oxide particles having photocatalytic activity under specific conditions. It has been found that a photocatalyst coating material capable of achieving the above can be obtained. The present invention has been made based on such knowledge of the inventors.

  A photocatalyst coating material according to the present invention includes an aluminum material, a photocatalyst layer formed on the surface of the aluminum material and containing metal oxide particles having photocatalytic activity, and the aluminum material and the photocatalyst layer. An intervening layer containing aluminum and carbon is formed.

  Moreover, in the photocatalyst coating material of this invention, it is preferable that the thickness of a photocatalyst body layer is 1 nm or more and 10 micrometers or less.

  Furthermore, in the photocatalyst coating material of the present invention, the intervening layer preferably contains crystallized aluminum carbide.

  An article according to the present invention comprises a photocatalytic coating material having the characteristics described above.

  The method for producing a photocatalyst coating material according to the present invention includes a photocatalyst layer forming step of forming a photocatalyst layer containing metal oxide particles having photocatalytic activity on the surface of an aluminum material, and a space containing a hydrocarbon-containing substance. A heating step of heating in a state where the aluminum material on which the photocatalyst layer is formed is disposed.

  In the method for producing a photocatalyst coating material of the present invention, the heating step is preferably performed at a temperature of 450 ° C. or higher and lower than 660 ° C.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness between the aluminum material as a base material and a photocatalyst body layer can be improved.

(Aluminum material)
The photocatalyst coating material of the present invention includes an aluminum material as a base material on which the photocatalyst layer is formed. The aluminum material as a base material is not specifically limited. In one embodiment of the present invention, a pure aluminum or aluminum alloy foil or plate can be used as the aluminum material. Such an aluminum material preferably has an aluminum purity of 98% by mass or more as a value measured according to the method described in “JIS H 2111”. The aluminum material used in the present invention has a composition of lead (Pb), silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc ( Zn alloy, titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni), and aluminum alloy to which at least one alloy element is added within the necessary range, or the above inevitable It also includes aluminum with limited impurity element content. The thickness of the aluminum material is not particularly limited, but in general, it is preferably 5 to 200 μm for the foil and 0.2 mm or more for the plate.

  What was manufactured by a well-known method can be used for said aluminum material. For example, a molten aluminum or aluminum alloy having the above predetermined composition is prepared, and an ingot obtained by casting the molten metal is appropriately homogenized. Then, the aluminum material as a base material can be obtained by subjecting this ingot to hot rolling and cold rolling. In addition, you may perform an intermediate annealing process at the temperature of 150 to 400 degreeC in the middle of said cold rolling process.

  Further, before the step of forming the photocatalyst layer, the aluminum material may be appropriately pretreated.

(Photocatalyst layer)
In the photocatalyst coating material of the present invention, a photocatalyst layer containing metal oxide particles having photocatalytic activity is formed on the surface of an aluminum material as a base material. The metal oxide particles having photocatalytic activity contained in the photocatalyst layer are not particularly limited. In one embodiment of the present invention, examples of the metal oxide particles include titanium oxide, zinc oxide, zirconium oxide, tungsten oxide and the like, and in particular, anatase-type titanium oxide particles. Preferably used.

  The shape and size of the metal oxide particles having photocatalytic activity contained in the photocatalyst body layer are not particularly limited, but the size (particle diameter) of the dispersed particles is 0.01 nm or more and 10 μm or less in order to increase the photocatalytic activity. In particular, 1 nm to 150 nm is preferable. The particle diameter is obtained by calculating the particle diameter by selecting 50 arbitrary particles from a photograph of a cross-sectional observation using a scanning transmission electron microscope (STEM), and calculating the particle diameter.

  The photocatalyst layer is, for example, a coating solution in which metal oxide particles having photocatalytic activity are emulsified in a solution using a stirrer or the like, and a precursor material of metal oxide having photocatalytic activity is hydrolyzed in solution. It is formed by applying a coating solution formed into particles by hydrothermal treatment or the like, or a coating solution obtained by mixing the above two coating solutions onto the surface of an aluminum material as a substrate.

  The thickness of the photocatalyst layer may be 1 nm or more and 10 μm or less, and particularly preferably 2 μm or less, from the viewpoint of ensuring adhesion between the substrate and the photocatalyst layer.

  Although the adhesion between the aluminum material and the photocatalyst layer is ensured by the presence of an intervening layer containing aluminum and carbon, which will be described later, as a method for further improving the adhesion, a metal is used when forming the photocatalyst layer. An oxide precursor substance (peroxotitanic acid aqueous solution or the like) or an organic binder such as a resin may be added to the coating solution. For example, a metal oxide having photocatalytic activity in a solution gelled from a solution (sol) containing a metal oxide precursor substance using a reaction of hydrolysis and polycondensation of an organic compound or metal salt of a metal alkoxide What is necessary is just to apply | coat the coating liquid prepared by disperse | distributing particle | grains on the surface of an aluminum material. Alternatively, a coating solution prepared by adding a carbon-containing component as an organic binder such as a resin to a coating solution obtained by emulsifying metal oxide particles in a solution is applied onto the surface of an aluminum material. Good.

(Intervening layer)
In the photocatalyst coating material of the present invention, an intervening layer containing aluminum and carbon is formed between the aluminum material as the base material and the photocatalyst layer. The intervening layer is obtained by heating an aluminum material having a photocatalyst layer formed on the surface in an atmosphere containing a hydrocarbon-containing substance.

  Since the intervening layer does not cover the surface of the metal oxide particles having photocatalytic activity contained in the photocatalyst layer, the intervening layer does not affect the photocatalytic activity, and between the aluminum material as the substrate and the photocatalyst layer. It works to improve adhesion.

  As described above, when the photocatalyst layer is formed, the adhesion between the aluminum material and the photocatalyst layer can be further improved by adding a metal oxide precursor material or a binder to the coating solution. In this case, the photocatalytic activity may be reduced by covering the surface of the metal oxide particles having photocatalytic activity with the metal oxide precursor substance or binder (carbon-containing component) added to the coating solution. . However, in the photocatalyst coating material of the present invention, since the adhesion between the aluminum material and the photocatalyst layer can be ensured by the intervening layer itself containing aluminum and carbon, the coating liquid is used to further improve the adhesion. The amount of metal oxide precursor material or binder added is small, and it is possible to minimize the effect on the photocatalytic activity. In this case, the addition of the metal oxide precursor material or the binder causes the metal oxide precursor material or the carbon-containing component to exist between the aluminum material as the base material and the photocatalyst layer, so that the aluminum material Not only can the adhesion between the photocatalyst layer be further increased, but also the adhesion between the metal oxide particles can be enhanced by being present between the metal oxide particles contained in the photocatalyst layer.

  The intervening layer preferably contains crystallized aluminum carbide.

(Articles with photocatalytic function)
By applying the photocatalyst coating material of the present invention to various articles, an article having a photocatalytic function can be constituted. The article having the photocatalytic function is not particularly limited. For example, there are various types such as decomposition or detoxification of harmful substances contained in the atmosphere, water, etc., deodorization of living space, prevention of contamination of solid surface in living space, antibacterial activity of living space Goods used for environmental purification. Specifically, examples of the article include building materials such as wallpaper, blinds, curtains and guardrails, industrial and household appliances such as air purifiers, air conditioners and refrigerators, and fin materials such as heat exchangers. .

(Method for producing photocatalyst coating material)
The method for producing a photocatalyst coating material according to the present invention comprises a step of forming a photocatalyst layer containing metal oxide particles having photocatalytic activity on the surface of an aluminum material (photocatalyst layer forming step), and then a hydrocarbon-containing substance. And a step of heating (heating step) in a state where the aluminum material on which the photocatalyst body layer is formed is disposed in the containing space.

  In the photocatalyst layer forming step, as described above, the metal oxide precursor material or the carbon-containing component is added together with the metal oxide particles having photocatalytic activity by adding the metal oxide precursor material or the binder to the coating liquid. After the formation of the photocatalyst layer containing, the aluminum material having the photocatalyst layer formed thereon is heated in the space containing the hydrocarbon-containing substance, and the adhesion between the aluminum material as the substrate and the photocatalyst layer is increased. Further improvement can be achieved.

<Photocatalyst layer forming step>
In the method for producing a photocatalyst coating material of the present invention, first, a photocatalyst layer containing metal oxide particles having photocatalytic activity is formed on the surface of an aluminum material. The method for forming the photocatalyst layer on the surface of the aluminum material as the substrate is not particularly limited. For example, a coating solution in which metal oxide particles having photocatalytic activity are emulsified in a solution using a stirrer or the like, a precursor material of metal oxide having photocatalytic activity is hydrolyzed, hydrothermally treated, etc. in the solution. A particulate coating solution or a coating solution obtained by mixing the above two coating solutions may be prepared and applied onto the surface of the aluminum material. The application method is not particularly limited, and a spin coating method, a bar coating method, a flow coating method, or a dip coating method is appropriately employed. If necessary, the aluminum material having the photocatalyst layer formed on the surface is dried if necessary. The thickness of the photocatalyst layer can be controlled by the number of coatings, the composition and concentration of the coating solution. The thickness of the photocatalyst layer formed by coating is not particularly limited, but from the viewpoint of ensuring adhesion between the substrate and the photocatalyst layer, it may be 1 nm or more and 10 μm or less, and particularly 2 μm or less. It is preferable.

  Further, as described above, when forming the photocatalyst layer, a metal oxide precursor material (peroxotitanic acid aqueous solution or the like) or an organic binder such as a resin may be added to the coating solution. In this case, the mass ratio of the binder in the photocatalyst layer is not particularly limited, but usually the solid content of the coating liquid is preferably 100 parts by mass, and the binder is preferably 90 parts by mass or less, and is preferably 10 parts by mass or less. It is more preferable.

  The organic binder is not particularly limited. Examples of organic binders include carboxy-modified polyolefin resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride copolymer resin, vinyl alcohol resin, vinyl fluoride resin, acrylic resin, polyester resin, urethane resin, epoxy resin, urea Examples thereof include binders of synthetic resins such as resins, phenol resins, acrylonitrile resins, nitrocellulose resins, paraffin wax, polyethylene wax, and natural resins such as wax, tar, glue, urushi, pine resin, beeswax and the like. In the heating step after the photocatalyst layer forming step, for example, it is more preferable to use a resin binder that is not completely volatilized by heating at a temperature of 450 ° C. or more and less than 660 ° C. for 1 hour or more and 100 hours or less in a hydrocarbon atmosphere preferable. When the binder is completely volatilized in the heating process in a hydrocarbon atmosphere, the adhesion between the aluminum material as the base material and the photocatalyst layer is lower than when a resin that does not completely volatilize is used as the binder. It will be.

  The solvent used appropriately with the organic binder is not particularly limited. The solvent is preferably a parent solvent for the binder (a solvent in which the binder is easy to dissolve). Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl acetate, aromatic solvents such as toluene and xylene, n-pentane, n-hexane, n-heptane, n- Aliphatic solvents such as octane, alicyclic solvents such as cyclohexane, methylcyclohexane and cyclopentane, alcohol solvents such as methanol, ethanol and isopropyl alcohol, glycol solvents such as ethylene glycol and propylene glycol, propylene glycol monomethyl ether And glycol ether solvents such as dipropylene glycol monomethyl ether, water and the like.

<Heating process>
In the method for producing a photocatalyst coating material of the present invention, after the photocatalyst layer forming step, heating is performed in a state where an aluminum material in which the photocatalyst layer is formed is arranged in a space containing a hydrocarbon-containing substance. The kind of said hydrocarbon containing substance is not specifically limited. Examples of the hydrocarbon-containing material include paraffinic hydrocarbons such as methane, ethane, propane, n-butane, isobutane and pentane, olefinic hydrocarbons such as ethylene, propylene, butene and butadiene, and acetylenes such as acetylene. Examples thereof include hydrocarbons and derivatives of these hydrocarbons. Among these hydrocarbons, paraffinic hydrocarbons such as methane, ethane, and propane are preferable because they become gaseous in the process of heating the aluminum material having the photocatalyst layer formed on the surface. More preferred is any one of methane, ethane and propane. The most preferred hydrocarbon is methane.

  The hydrocarbon-containing substance may be used in any state such as liquid or gas. The hydrocarbon-containing material may be present in a space where the aluminum material having the photocatalyst layer formed on the surface thereof is present, and any method can be used in the space in which the aluminum material having the photocatalyst layer formed on the surface is disposed. May be introduced. For example, when the hydrocarbon-containing substance is in a gaseous state (methane, ethane, propane, etc.), the hydrocarbon-containing substance may be filled alone in the sealed space where the heating step is performed, together with an inert gas. It may be filled or may be filled with a reducing gas such as hydrogen gas. Further, when the hydrocarbon-containing substance is a liquid, the hydrocarbon-containing substance may be filled alone or with an inert gas so as to vaporize in the sealed space, or hydrogen You may fill with reducing gas, such as gas.

  In the heating step, the pressure of the heating atmosphere is not particularly limited, and may be normal pressure, reduced pressure, or increased pressure. Further, the pressure adjustment may be performed at any time during the temperature rise to a certain heating temperature or during the temperature lowering from the certain heating temperature while the pressure is maintained at a certain heating temperature.

  The mass ratio of the hydrocarbon-containing substance introduced into the space in which the aluminum material on which the photocatalyst layer is formed is arranged is not particularly limited, but is usually 0.1 in terms of carbon with respect to 100 parts by mass of the aluminum material. The amount is preferably from 50 parts by weight to 50 parts by weight, and particularly preferably from 0.5 part by weight to 30 parts by weight.

  In the heating step, the heating temperature may be appropriately set according to the composition of the aluminum material that is the heating object, but is usually preferably 450 ° C. or higher and lower than 660 ° C., more preferably 530 ° C. or higher and 620 ° C. or lower. By setting the heating temperature to 450 ° C. or higher, crystallized aluminum carbide can be contained in the intervening layer containing aluminum and carbon. However, in the production method of the present invention, heating the aluminum material having the photocatalyst layer formed on the surface at a temperature of less than 450 ° C. is not excluded, and the photocatalyst layer is at least at a temperature exceeding 300 ° C. What is necessary is just to heat the aluminum material formed in the surface.

  Although the heating time depends on the heating temperature and the like, it is generally 1 hour or more and 100 hours or less.

  When the heating temperature is 400 ° C. or higher, the oxygen concentration in the heating atmosphere is preferably 1.0% by volume or lower. When the heating temperature is 400 ° C. or higher and the oxygen concentration in the heating atmosphere exceeds 1.0% by volume, the thermal oxide film on the surface of the aluminum material is enlarged, which inhibits the formation of an intervening layer containing aluminum and carbon, and adherence May decrease.

<Oxidation process>
In the above heating step, the metal oxide particles contained in the photocatalyst layer may be reduced depending on the type thereof, and the photocatalytic activity of the photocatalyst layer may be reduced. You may perform oxidation processes, such as the oxidation heating process and the anodic oxidation process which anodize the aluminum material formed in the surface in an oxidizing atmosphere. Thereby, the photocatalytic activity of a photocatalyst body layer can be revived.

  In addition, since the atmosphere containing the hydrocarbon-containing substance is a reducing atmosphere, the natural oxide film formed on the surface of the aluminum material is reduced during the heating process and disappears completely, or compared with before the heating process. As a result, the thickness of the natural oxide film may decrease. In this case, there is a possibility that the aluminum material may be corroded when the part where the natural oxide film has disappeared or the part where the thickness of the natural oxide film is reduced comes into contact with the humidity or the like of the use environment. However, when the oxidation process is performed after the heating process, the oxidation of the portion where the surface of the aluminum material is exposed by the reduction is promoted. As a result, since the aluminum oxide film is formed on the surface of the aluminum material as the base material before the photocatalyst coating material of the present invention is placed in the use environment, the metal generated by touching the moisture or the like in the use environment The progress of the corrosion is suppressed, and the quality of the photocatalyst coating material can be prevented from deteriorating with time.

  In the above oxidation heating step, the oxidizing atmosphere means that oxygen exists in the space where the aluminum material having the photocatalyst layer formed on the surface is disposed, and oxygen may be filled alone, or Oxygen may be filled together with a non-reducing gas. The oxidizing atmosphere is preferably a space containing 2 volume% or more and 50 volume% or less of oxygen. The heating temperature is usually preferably 200 ° C. or higher and 660 ° C. or lower. Although the heating time depends on the heating temperature and the like, it is generally preferable that the heating time is 10 seconds or more and 50 hours or less.

  The anodic oxidation step is not particularly limited, and may be performed, for example, by applying a voltage of 1000 V or less to an aluminum material having a photocatalyst layer formed on the surface in a solution such as phosphoric acid or sulfuric acid.

  Samples of the photocatalyst coating material were prepared according to the following Examples 1 to 5 and Comparative Examples 1 to 3.

Example 1
An aluminum foil having a thickness of 50 μm and a purity of 99.3% by mass is immersed in an aqueous solution in which 1% by mass of anatase-type titanium oxide particles (metal oxide particles having photocatalytic activity) having an average particle diameter of 6 nm are dispersed. Thus, a photocatalyst layer having a thickness of 0.1 μm on one side was formed on both sides of the aluminum foil.

  Thereafter, the aluminum foil having the photocatalyst layer formed on the surface was held in a methane gas atmosphere at a temperature of 610 ° C. for 12 hours to prepare a sample of the photocatalyst coating material.

(Example 2)
A sample of the photocatalyst coating material was prepared by holding the sample prepared in Example 1 above in air at a temperature of 600 ° C. for 12 hours.

(Comparative Example 1)
In Example 1 above, a sample of the photocatalyst coating material was prepared by holding an aluminum foil having a photocatalyst layer formed on the surface by immersing the aluminum foil in an aqueous solution at a temperature of 610 ° C. for 12 hours in air. Was made.

(Example 3)
A mixture of Ti (n-OC ₃ H ₇ ) ₄ : 1 mol and C ₃ H ₇ OH: 1 mol was stirred into a mixture of H ₂ O ₂ : 1.5 mol and H ₂ O: 10 mol. The solution containing the water-soluble titanium complex as the metal oxide precursor material, which was subjected to the stabilization treatment by adding dropwise over 1 hour while performing the above, was prepared.

  The above solution is placed in a stainless steel container, and bead milling is performed for 2 hours using zirconia beads having a diameter of 0.3 mm, whereby anatase-type titanium oxide having an average particle size of 130 nm in the above solution. Product particles (metal oxide particles having photocatalytic activity) were dispersed to prepare a coating solution. In the obtained coating liquid, the mass ratio of the water-soluble titanium complex (metal oxide precursor substance) in the total solid mass is 1 mass%, and the mass ratio of the titanium oxide particles (metal oxide particles having photocatalytic activity) is It was 99 mass%.

  The above coating solution was applied to the surface of an aluminum foil having a thickness of 50 μm and a purity of 99.3% by mass using the bar coating method, and then heated and dried in air at a temperature of 120 ° C. for 3 minutes. The thickness of the obtained photocatalyst layer was about 0.5 μm.

  A sample of the photocatalyst coating material was prepared by holding the aluminum material having the photocatalyst layer formed on the surface thereof in a methane gas atmosphere at a temperature of 610 ° C. for 12 hours.

Example 4
A sample of the photocatalyst coating material was prepared by holding the sample prepared in Example 3 above in air at a temperature of 610 ° C. for 12 hours.

(Comparative Example 2)
In Example 3 above, the sample of the photocatalyst coating material was prepared by holding the aluminum foil having the photocatalyst layer formed on the surface thereof by application to the surface of the aluminum foil at a temperature of 610 ° C. for 12 hours in the air. Produced.

(Example 5)
By placing a polyvinyl alcohol-based resin as a binder in a stainless steel container and performing bead milling for 2 hours using zirconia beads having a diameter of 0.3 mm, the average particle diameter is 16 nm in the resin. Anatase type titanium oxide particles (metal oxide particles having photocatalytic activity) were dispersed to prepare a coating solution. In the obtained coating liquid, the mass ratio of the resin (binder: carbon-containing component) in the total solid mass is 25 mass%, and the mass ratio of the titanium oxide particles (metal oxide particles having photocatalytic activity) is 75 mass%. there were.

  The above coating solution was applied to the surface of an aluminum foil having a thickness of 30 μm and a purity of 99.3% by mass using a bar coating method, and then heated and dried in air at a temperature of 200 ° C. for 1 minute. The thickness of the obtained photocatalyst layer was about 2.5 μm.

  A sample of the photocatalyst coating material was prepared by holding the aluminum material with the photocatalyst layer formed on the surface in a methane gas atmosphere at a temperature of 610 ° C. for 16 hours.

(Comparative Example 3)
In Example 5 above, a sample of the photocatalyst coating material was prepared by holding the aluminum foil having the photocatalyst layer formed on the surface thereof by application to the surface of the aluminum foil at a temperature of 610 ° C. for 16 hours in the air. Produced.

  Regarding the photocatalyst coating materials of Examples 1 to 5 and Comparative Examples 1 to 3 obtained as described above, the evaluation of the adhesion between the photocatalyst layer and the aluminum material is performed by peeling with a tensile tester using an adhesive tape. The test was conducted. In a sample of a photocatalyst coating material having a width of 10 mm and a length of 100 mm, a pressure-sensitive adhesive tape (trade name “cellophane tape” manufactured by Sekisui Chemical Co., Ltd.) having an adhesive surface with a width of 18 mm and a length of 120 mm on the surface of the photocatalyst layer. It was pressed and cut to a width of 10 mm. Then, peel strength [N / cm] required to peel off the adhesive tape with a tensile tester at a peel angle of 90 ° and a peel speed of 200 mm / min was measured. As the peel strength value, a stable value was adopted after the start of measurement. For each sample, the peel strength was measured at three locations, and the adhesion was evaluated by the average value. Table 1 shows the average peel strength measured for each sample.

  From Table 1, the photocatalyst coating material obtained in Examples 1 and 2 of the present invention was compared with the photocatalyst coating material obtained in Comparative Example 1, and the photocatalyst coating material obtained in Examples 3 and 4 was Comparative Example 2. It can be seen that the photocatalyst coating material obtained in Example 5 shows higher adhesion than the photocatalyst coating material obtained in Comparative Example 3 as compared with the photocatalyst coating material obtained in 1. In addition, when each sample of the photocatalyst coating material obtained in Examples 1 to 5 was observed with a scanning electron microscope, an intervening layer containing crystallized aluminum carbide was formed between the aluminum material and the photocatalyst layer. It was confirmed that it was formed.

(Comparative Example 4)
In Example 5 described above, an aluminum foil having a photocatalyst layer formed on the surface by coating on the surface of the aluminum foil was directly used as a sample of the photocatalyst coating material. That is, in Comparative Example 4, a sample of the photocatalyst coating material was produced in the same manner as in Example 5 except that the sample was held in a methane gas atmosphere at 610 ° C. for 16 hours in Example 5.

  About the photocatalyst coating material obtained in Examples 2, 4, 5 and Comparative Example 4, a deterioration test was performed using a weather resistance tester (Isuper UV tester, model: SUV-W151 manufactured by Iwasaki Electric Co., Ltd.) by ultraviolet irradiation. Went. Specifically, the photocatalyst coating materials of Examples 2, 4, 5 and Comparative Example 4 were placed in the above weather resistance tester, and these photocatalyst coating materials were irradiated with ultraviolet rays under the following conditions.

UV irradiation conditions: UV was irradiated to the photocatalyst coating material for 90 hours at a temperature of 60 ° C., a humidity of 50%, and an illuminance of 100 W / m ² .

  In the above degradation test, the adhesion between the photocatalyst layer and the aluminum material was evaluated for the photocatalyst coating material before irradiation with ultraviolet rays and the photocatalyst coating material after irradiation with ultraviolet rays. The evaluation of adhesion was performed by the same method as the peel test using the tensile tester described above.

  From Table 2, in Example 2, 4, 5 of this invention, a change is not looked at by adhesiveness (peeling strength) between before and after ultraviolet irradiation in a deterioration test. On the other hand, in Comparative Example 4, it can be seen that the adhesion after irradiation with ultraviolet rays in the deterioration test is significantly reduced as compared with that before irradiation with ultraviolet rays. From these results, as in Comparative Example 4, when an organic material was used as a binder and a photocatalyst layer containing metal oxide particles having photocatalytic activity was to be immobilized on an aluminum material as a substrate, It can be seen that the binder itself deteriorates due to the photocatalytic action of the photocatalyst layer, and the adhesion between the photocatalyst layer and the aluminum material decreases. On the other hand, as in Examples 2, 4, and 5, when the photocatalyst layer is immobilized on the surface of the aluminum material by the method of the present invention, the adhesion after irradiation with ultraviolet rays in the deterioration test is irradiated with ultraviolet rays. It turns out that it does not fall compared with before.

  It should be considered that the embodiments and examples disclosed above are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the claims.

According to the present invention, the adhesion between the aluminum material as a base material and the photocatalyst body layer can be improved, so that the photocatalyst coating material of the present invention can be used for various environmental purifications by applying it to various articles. It becomes possible to do.

Claims (6)

Aluminum material,
A photocatalyst layer comprising metal oxide particles having photocatalytic activity formed on the surface of the aluminum material;
An intervening layer containing aluminum and carbon formed between the aluminum material and the photocatalyst layer;
A photocatalytic coating material comprising:   The photocatalyst coating material according to claim 1, wherein the photocatalyst layer has a thickness of 1 nm or more and 10 µm or less.   The photocatalyst coating material according to claim 1, wherein the intervening layer includes crystallized aluminum carbide.   An article comprising the photocatalyst coating material according to claim 1. A photocatalyst layer forming step of forming a photocatalyst layer containing metal oxide particles having photocatalytic activity on the surface of the aluminum material;
A heating step of heating the aluminum material in which the photocatalyst layer is formed in a space containing a hydrocarbon-containing substance; and
A method for producing a photocatalyst coating material comprising: The said heating process is a manufacturing method of the photocatalyst coating material of Claim 5 performed at the temperature of 450 degreeC or more and less than 660 degreeC.