JP2002212464A - Photocatalyst cream and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that when a photocatalyst is applied outdoors by spraying, roller coating, brush coating, or the like, the influence of disturbance such as wind, temperature, or humidity can not be avoided, necessitating a protection apparatus and that liquid sagging and uneven coating on the surface of a substrate occurs, spoiling the external appearance. SOLUTION: A photocatalyst material prepared by combining a photocatalyst with at least one inorganic substance selected from among silica, alumina, zirconia, etc., is made creamy by incorporating water in an amount of 5-30 wt.% (based on the total solid content) into the material. A simple and convenient coating method for forming a photocatalyst coating film excellent in transparency on the surface of a substrate is provided; the method comprises applying the photocatalyst material in a creamy state to the surface of a substrate, e.g. a structure, drying the applied material, and removing a white crystallized dry substance appearing on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a creamy photocatalyst capable of applying a photocatalyst to the surface of a base material such as glass or tile constituting a large-sized structure without using any special coating equipment or technique. The present invention also relates to a coating technique capable of coating a substrate surface without being affected by disturbance such as wind.

[0002]

2. Description of the Related Art In recent years, utilization of photocatalysts has been attempted from the viewpoint of maintaining and recovering a healthy environment. Photocatalyst uses sunlight, which is inexhaustible energy, to detoxify odorous substances such as aldehydes and ammonia, harmful substances such as NOx, and benzene, and to decompose and remove oil components that cause adhesion of dirt. Has a difficult function. Also,
By storing the energy of light, it also has a hydrophilic property that is well compatible with water. Photocatalysts emit harmful substances and are regulated by the Odor Control Law, because reactive radical species such as hydroxyl radicals and superoxide anions are expressed on the surface of the photocatalyst by irradiation with ultraviolet rays together with hydrophilic functions. Deodorant decomposition, antifouling,
Use as environmental purification materials such as sterilization is increasing.

On the other hand, a technique using titanium oxide as a cream has been used as a cosmetic or therapeutic agent. The details will be described below.

In Japanese Patent Application Laid-Open No. 11-217322, 4
There is a proposal of a cosmetic which has a tert-butyl-4-methoxydibenzoylmethane and ultrafine particle titanium oxide coated with silica on the surface of a composite pigment, has an excellent ultraviolet absorbing effect, and has high stability over time. It is stated that these are effective for use in cosmetics, such as sunscreen creams, sunscreen emulsions, lipsticks, and foundations.

In Japanese Patent No. 2572520, there is a proposal as a semiconductor therapeutic agent, and p-type titanium oxide is used for toning, and is used by being mixed with a cream. In the above patent, there is no action as a photocatalyst, and no proposal for utilization in environmental purification is made.

Techniques for applying a photocatalyst to a substrate such as a structure include a spray method, a brush coating method, and a roller method. In each method, a photocatalyst-containing liquid is sprayed by a spray, or the liquid is impregnated into a brush or a roller, and the photocatalyst is applied to a target substrate surface.

[0007] Japanese Patent No. 2918112 proposes a method for producing a coating material containing anatase-type titanium oxide which is rich in photocatalytic activity by subjecting a titania sol solution or the like to a heat treatment and a pressure treatment in a closed container at the same time. I have.

Japanese Patent Application Laid-Open No. Hei 8-257360 discloses a technique for producing a coating material in which an anatase type titanium oxide powder prepared in advance is dispersed in water together with fine cellulose, and then polyaluminum chloride is added as a coagulant. I have.

JP-A-11-001620 proposes a coating material in which a polyorganosiloxane, a vinyl polymer and semiconductor fine particles having a photocatalytic function are dispersed in an aqueous medium.

[0010]

However, in the case of applying by the above method, the spray method is affected by disturbance such as wind, so that a windshield is required. There are problems such as the influence of moisture in the air such as temperature and humidity, or the inclusion of dust in the air. In addition, in the case of roller coating or brush coating, a coating material impregnated with the coating material has a problem of dripping on the substrate surface.

The present invention has been devised in view of the above-mentioned various problems, and an object of the present invention is to provide a special coating on the surface of a base material such as glass, tile, metal, etc., which constitutes a large-sized structure particularly in outdoor application. An object of the present invention is to provide a cream-like photocatalyst that can apply a photocatalyst without using an application facility and technique, and to provide an application technique that can apply the photocatalyst to a substrate surface without being affected by disturbance such as wind.

[0012]

In order to solve the above-mentioned problems, the present invention relates to a photocatalyst comprising a photocatalyst and an inorganic material such as silica, alumina, zirconia or a combination of two or more components, wherein water is added to the total solid content. Is in the form of a cream by containing 5 to 30% by weight. Also,
After coating the cream-like photocatalyst (hereinafter referred to as "photocatalyst cream") on the surface of a base material such as a structure, the dried product which is white and crystallized on the surface after drying is removed, so that the surface of the base material is excellent in transparency. An object of the present invention is to provide a simple application method capable of coating a photocatalyst.

In the present invention, any photocatalyst can be used, but amorphous titanium oxide, anatase titanium oxide, brookite titanium oxide, rutile titanium oxide, zinc oxide, barium titanate, strontium titanate, Tungsten oxide, manganese oxide,
Ruthenium oxide and cadmium sulfide are preferred. In particular, amorphous titanium oxide, anatase titanium oxide, brookite titanium oxide, and rutile titanium oxide are most suitable in terms of safety, durability with chemicals, transparency, and the like.

In these methods of the present invention, platinum, gold, silver, copper, magnesium, aluminum,
Metals such as potassium, calcium, vanadium, chromium, manganese, cobalt, nickel, zinc, selenium, zirconium, molybdenum, palladium, tin, hafnium, and tungsten; minerals such as zeolite, cordierite, and mullite; polymethacrylate resins, fluororesins, and silicon At least one of organic and inorganic polymers such as resins and aromatic organic polymers can be added. By adding a metal to the photocatalyst surface, it is possible to suppress an increase in the number of radicals generated by photoexcitation and deactivation of radicals. Also, by adding an inorganic substance, an organic polymer, or ethanol, isopropyl alcohol, or butanol represented by the structural formula of CnH2n + 1OH, it is possible to improve physical properties such as transparency, gloss, and adhesion of the coated surface. is there.

As for silica, alumina and zeolite, particles of 2 to 30 nm can be used. What is necessary is just to disperse and use in the solution adjusted to predetermined hydrogen ion concentration.

As a raw material for producing a photocatalyst cream, a photocatalyst is dispersed and a solution in which the hydrogen ion concentration is adjusted to 0.5 to 6.5 and silica, alumina, zirconia and the like are dispersed, and a hydrogen ion concentration is adjusted to 8 to 13. The used solution can be used. Regarding the hydrogen ion concentration of the solution in which titanium oxide, silica, alumina, and zirconia are dispersed, the above-described reverse combination may be used.

As a coating method, a photocatalyst cream is applied to the surface of the substrate moistened with water or the like in an amount of 30 g to 2 g per m 2.
After taking 00g, apply it to cloth, paper, etc. at a temperature of 5 ° C to 40 ° C, spread the photocatalyst cream on the surface of the base material, and after drying, remove the solid matter that has emerged white on the base material surface with another cloth, paper, etc. do it. 30g of photocatalyst cream per 1m2
If the amount is smaller, a sufficient photocatalytic function cannot be secured. On the other hand, when the amount is more than 200 g per 1 m 2, the function of the photocatalyst is sufficient, but it is difficult to remove solids, and there is a problem in securing design properties.

[0018]

Next, embodiments of the present invention will be described. In the present embodiment, a photocatalytic cream using titanium oxide and silica is described as an example,
The above-mentioned photocatalysts, mixed photocatalysts, alumina, zirconia and mixtures thereof can of course be used.
Titanium oxide is prepared from various raw materials such as titanium alkoxide,
Any of those manufactured from titanium oxalate, titanium nitrate, titanium tetrachloride and the like can be used. Examples of the titanium alkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopolopoxide, titanium tetrabutoxide and the like. Examples of the solvent to be dispersed include distilled water and ion-exchanged water. Examples of the silica dispersion include adding a silicon halide such as silicon tetrachloride to water and adding an acidic substance such as hydrochloric acid and nitric acid to an aqueous solution of an alkali silicate such as sodium silicate.

An acidic solution in which titanium oxide was dispersed was added to the above alkaline solution in which silica was dispersed. In addition,
The temperature at the time of mixing ranges from 15 ° C. to 80 ° C. An acidic substance such as hydrochloric acid or nitric acid, an alkaline substance such as ammonia or amine, a surfactant for maintaining dispersibility, a polymethacrylic acid resin, a silicon resin, CnH2n + 1
Ethanol, isopropyl alcohol, butanol, etc. represented by the structural formula of OH are added.

By mixing the above ingredients, a photocatalytic cream without dripping is obtained after 50 hours. 30g / m2 of photocatalyst cream on the surface of the substrate moistened with water etc.
From 200g to a cloth, paper, etc. at a temperature of 5 ° C to 40 ° C, spread the photocatalyst cream on the surface of the base material, and after drying, separate the solid matter that emerged white on the base material surface with another cloth.
If it is removed with paper or the like, it becomes possible to form a photocatalytic coating while maintaining the design.

[0021]

Example 1 53.7 g of an anatase-type titanium oxide dispersion having a hydrogen ion concentration of 1 was added to 156 g of a silica dispersion having a hydrogen ion concentration of 10 (solid content concentration: 22.5 wt%).
(Solid content: 19.3 wt%) at 25 ° C.
A photocatalytic cream (solid content concentration: 21.7 wt%) was prepared by maintaining the composition at 25 ° C. for 50 hours. 1. Photocatalytic cream on the surface of commercial glass (10 cm square) moistened with water
5 g was applied with paper, spread over and coated. After the coating was dried for 1 minute, a white crystallized solid was removed. 0.7 solids adhered to glass surface
g. Turbidity measurement (JIS K7631) revealed that the total light transmittance was 90% and the haze value was 0.08. The numerical value of the pencil hardness was 5H. The contact angle of the coated glass was 12 degrees, and a hydrophilic effect was confirmed immediately after coating. 0.2 g, 0.5 g, 1.0 g, 1.5 g, 2.0 g of the application amount of the photocatalytic cream,
Table 1 shows the physical properties of the glass produced with 3.0 g and 4.0 g. The table shows the transmittance and hydrophilicity when coating on glass in Example 1.

[0022]

[Table 1]

[0023]

Example 2 68 g of anatase-type titanium oxide dispersion having a hydrogen ion concentration of 9 (solid content: 20 wt%) was mixed at 25 ° C. with 194 g of an alumina dispersion having a hydrogen ion concentration of 3 (solid content: 20 wt%). did. The photocatalyst cream was prepared by holding at 25 ° C. for 70 hours. 25 ° C
1. On paper of commercially available glass (10 cm square) by paper.
5 g was applied, spread all over with paper and coated. After the coating was dried for 1 minute, a white crystallized solid was removed. When turbidity measurement (JIS K7631) was performed, the total light transmittance was 90%, and the haze value was 0.08.
Met. The pencil hardness was 9H. The contact angle of the coated glass was 13 degrees, and the hydrophilic effect was confirmed immediately after coating. In the description of the above embodiment, cloth or paper is used as a tool to be applied, but the present invention is not limited to this.

[0024]

(1) Since the photocatalyst according to the present invention is made into a creamy form, it is not affected by disturbances such as wind and humidity when applied outdoors, and the base material such as glass, tile or metal constituting the structure is not affected. Anyone can apply the photocatalyst to the surface neatly without using any special coating equipment or technique, and evenly. (2) The hydrophilic function and the decomposition function of the photocatalyst have an effect of preventing contamination.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C09K 3/00 C09K 3/00 R 112 112Z (72) Inventor Masahiko Akamatsu 1 Kawasakicho, Akashi-shi, Hyogo Prefecture No. 1 Kawasaki Heavy Industries, Ltd. Akashi Factory (72) Inventor Seiji Terada 1-1, Kawasaki-cho, Akashi-shi, Hyogo Prefecture Kawasaki Heavy Industries Akashi Factory, Ltd. (72) Inventor Kenkichi Sakai 2--4 Hamamatsucho, Minato-ku, Tokyo No. 1 Kawasaki Heavy Industries, Ltd.Tokyo head office No. 1 Kawasaki Heavy Industries, Ltd. Akashi Factory F-term (reference) 4G059 AA01 AA02 AB09 AC22 DA01 DA02 DA03 DA04 DA05 DA06 DA07 DA09 EA04 EB09 FA05 FA15 4G0 69 AA08 BA04A BA04B BA07A BA13A BA48A BB02A BB04A BB06A BC03A BC09A BC10A BC12A BC13A BC16A BC22A BC31A BC32A BC33A BC35A BC50A BC51A BC52A BC54A BC58A BC59A BC60A BC62A BC67A BC68A BC70A BC72A BC75A BD09A CD10 DA05 EA01X EA01Y EB18X EC22X EC22Y EC26 ZA01A 4J038 AA011 CG032 CR072 DL002 HA061 HA141 HA501 JA18 NA01 NA05 NA24 PB05 PC02 PC03

Claims (10)

[Claims] 1. A photocatalytic cream comprising a composition comprising a photocatalyst and one or two or more inorganic substances such as silica, alumina and zirconia, and containing 5 to 30% by weight of water with respect to the total solid content. . 2. The photocatalyst cream according to claim 1, wherein the solid content of the photocatalyst is 15% to 50%. 3. Photocatalysts include amorphous titanium oxide, anatase titanium oxide, brookite titanium oxide, rutile titanium oxide, titanium peroxide, zinc oxide, barium titanate, strontium titanate, tungsten oxide, manganese oxide, and manganese oxide. The photocatalyst cream according to any one of claims 1 to 2, wherein one of ruthenium or the like or a combination thereof is used. 4. The photocatalyst cream according to claim 1, wherein the particles constituting the photocatalyst have a particle size of 0.5 nm to 100 nm. 5. Amorphous alumina or alumina having a crystal structure of α, β,
The photocatalyst cream according to any one of claims 1 to 4, comprising γ or the like. 6. A photocatalyst cream containing an acidic substance, an alkaline substance, a surfactant, an organic polymer, an inorganic polymer, an organic / inorganic polymer, an organic solvent or a combination thereof. 5. The photocatalytic cream according to 5. 7. A photocatalyst comprising platinum, gold, silver, copper, magnesium, aluminum, potassium, calcium, vanadium, chromium, manganese, cobalt, nickel, zinc, selenium, zirconium, molybdenum, palladium, tin,
The photocatalytic cream according to any one of claims 1 to 6, wherein a metal such as hafnium or tungsten, or an inorganic material such as zeolite, cordierite or mullite or a combination thereof is added. 8. A solution in which a photocatalyst is dispersed in a solution having a hydrogen ion concentration of 0.5 to 6.5 and an alkaline solution having a hydrogen ion concentration of 8 to 13 are added to an inorganic solution such as silica, alumina or zirconia. The photocatalyst cream according to any one of claims 1 to 7, wherein the photocatalyst cream is produced by mixing a mixture of two or more components. 9. The photocatalyst having a hydrogen ion concentration of 8 to 13
Is mixed with an alkaline solution having a hydrogen ion concentration of 0.5 to 6.5 or a combination of two or more of inorganic substances such as silica, alumina, and zirconia. A photocatalytic cream according to any one of claims 1 to 7, wherein the cream is produced. 10. The photocatalyst cream according to claim 1 on a surface of a substrate moistened with water or the like.
Takes 0 g to 200 g, spreads the photocatalyst cream on the surface of the substrate at a temperature of 5 ° C. to 40 ° C., and after drying, removes solid matter that has emerged white on the surface of the substrate. A method for applying a photocatalyst cream, comprising coating a photocatalyst.