JP2000051708A - Photocatalyst coating film and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocatalyst coating film excellent in formability and light resistance by using a hydrolyzed polymn. condensate of trifunctional silane expressed by a specified formula and tetrafunctional silane expressed by a specified formula, titanium dioxide particles as a photocatalyst, silver as an antibacterial and antifungal agent, and copper as an antibacterial agent. SOLUTION: A hydrolyzed polymn. condensate of trifunctional silane expressed by the formula of RSi(X)3 (wherein R is a hydrocarbon group or the like and X is an alkoxyl group or the like) and tetrafunctional silane expressed by Si(X)4 (wherein X is an alkoxyl group or the like) is used as a binder source material for titanium dioxide particles as a photocatalyst. Silver salt and copper salt are added to the source material. Thereby, photocatalytic functions such as antibacterial and antifungal effects of the coating are improved to develop excellent antibacterial, antifungal and deodorizing functions. In this method, the silver component in the coating film contains silver ion and/or metal silver, and the concn. of silver ion, metal silver and/or silver compds. is controlled to 0.01 to 5 wt.% calculated as metal silver to the titanium dioxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalytic film having deodorizing, antibacterial, and antifungal functions and having excellent workability and light resistance, and a method for forming the same.

[0002]

2. Description of the Related Art It has long been known that, when a photocatalyst such as titanium dioxide is irradiated with light containing ultraviolet rays, organic substances are oxidatively decomposed. In recent years, application to applications such as deodorization, antibacterial, and mold prevention utilizing the effect of titanium dioxide has been studied. As a method of fixing titanium dioxide to a base material, a method in which a sol in which titanium dioxide particles are dispersed in water or an organic solvent is applied to the base material, dried, treated at a high temperature and sintered, and the titanium dioxide particles are mixed into a binder. However, in the case of the former sintering, the substrate is limited to a tile or the like that can withstand high-temperature firing. On the other hand, in the method using a binder, since firing at a relatively low temperature is possible, it can be applied to various substrates. Hydrolysis / polycondensation products such as alkoxysilanes and chlorosilanes can be fired at low temperatures, can be applied to various substrates, and are relatively inexpensive, so they are excellent binders for titanium dioxide particles.

Therefore, conventionally, in the invention of a titanium oxide coating film forming composition for a photocatalyst described in Japanese Patent Application Laid-Open No. 8-164334 and a process for producing the same, a hydrolyzable silicon compound such as alkoxysilane or chlorosilane is used as a binder for titanium dioxide. The photoreactive harmful substance removing agent described in Japanese Patent No. 2618287 and the harmful substance removing method using the same,
It has been reported that a film having an excellent photocatalytic effect can be obtained by using a hydrolysis product of a metal alkoxide such as an alkoxysilane as a binder for titanium dioxide.

[0004]

However, there is no description that the former film is poor in workability because all or most of the components are composed of inorganic components, and that the latter film is excellent in workability. Absent. Further, even in applications that do not require workability, for example, a conventional paint containing a binder made of an inorganic component and titanium dioxide particles does not peel when applied uniformly and thinly, but has a thickness of 0.5 to 1 μm. Cracks occur when the temperature reaches the limit, and the film tends to peel off.If the shape of the molded body to which the film is applied is complicated or it is difficult to form a uniform film even when applied to a flat plate, cracks will occur from the thickened part of the film. There is a problem in that it is difficult to use it for a post coat because it is easily peeled.

[0005] In the conventional method using such a hydrolyzable silicon compound such as alkoxysilane or chlorosilane as a raw material for a binder of titanium dioxide, in order to solve the problem that a film excellent in processability cannot be obtained, The present inventors have previously described the formula RSi (X) ₃ , wherein R is an alkyl group, a phenyl group, or a hydrocarbon group comprising a vinyl group,
Hydrolysis of a trifunctional silane represented by X (X is an alkoxyl group or halogen) and a tetrafunctional silane represented by the formula Si (X) ₄ (X is an alkoxyl group or halogen)・ Proposed an invention of a photocatalyst film having excellent processability and light resistance, using a polycondensate as a binder material of titanium dioxide particles as a photocatalyst (for example, Japanese Patent Application No. Hei 10-1998).
No. 183631).

However, in the previously proposed photocatalyst film prepared by adding a binder to titanium dioxide particles as a photocatalyst, the photocatalytic function may be insufficient depending on the use environment and application. In the environment, there was a problem that the antibacterial activity was not exhibited.

On the other hand, for example, P. Pichat, M.-N. Mozzanega, J.
Disdier, and J.-M. Herrmann, Nouv. J. Chim., 6, 559, (198
2), and H. Harada, Chem. Express, 6 [12], 961 (1991), etc., it is already known that supporting a small amount of a suitable metal on the photocatalyst improves the photocatalytic function. Have been.
Here, as the metal supported in a small amount on the photocatalyst, platinum,
Many of them include silver, copper, iron, cobalt and the like. Among them, silver, copper and the like have long been known to have a very strong antibacterial activity of the metal itself. The photocatalytic reaction by titanium dioxide is
Since it requires ultraviolet rays contained in sunlight, fluorescent lamps, ultraviolet lamps, etc., it cannot exert an antibacterial effect in a dark place, but imparts antibacterial power in a dark place by adding silver or copper. be able to.

By the way, since the photocatalytic reaction by titanium dioxide occurs on the surface of the titanium dioxide, if it is used for fungicide, the mold in contact with the titanium dioxide is decomposed, but at a position slightly away from the surface, the mold is exposed. Does not decompose,
Since it continues to grow, it is very difficult for titanium dioxide alone to exhibit a fungicidal effect even under light irradiation. On the other hand, silver is very effective not only for antibacterial activity but also for fungicide prevention. Therefore, it is very preferable to add silver for fungicide to form a photocatalytic film containing titanium dioxide.

When silver or copper is supported on a photocatalytic film containing titanium dioxide, silver or copper is generally added to the raw material as a metal salt, but silver ions are precipitated by photochemical reaction or oxidation. Since it has the property of turning into agglomerates or oxides and turning brown or black, if silver is added to the extent that it can exhibit a fungicidal effect, it will discolor due to heat during film baking or ultraviolet light when using the film. However, there is a problem that it cannot be used particularly in applications that emphasize aesthetics. On the other hand, when a copper salt is used, there is a problem that although the discoloration during the use of the film is small, it is difficult to exhibit the fungicide effect.

An object of the present invention is to solve the above-mentioned problems of the present invention proposed by the present inventors, and to obtain a compound represented by the formula RSi (X) _{3 wherein} R is an alkyl group, a phenyl group, or a vinyl group. A hydrocarbon group, X is an alkoxyl group or a halogen), and a formula Si (X)
₄ Excellent processability and light fastness by using a hydrolysis / polycondensate with a tetrafunctional silane represented by the formula (where X is an alkoxyl group or a halogen) as a binder material for titanium dioxide particles as a photocatalyst. By adding a copper salt together with a silver salt to the raw material, the photocatalytic film greatly improves the photocatalytic function of the prepared film, such as antibacterial, antifungal and deodorant. It has excellent antibacterial, antifungal, and deodorant functions and is easy to process.
Providing a photocatalytic film with excellent light resistance, and even when silver salt is added to the extent that it can exhibit a fungicidal effect, discoloration due to heat during baking and ultraviolet light during use of the film is small. Photocatalysts that can be used for various applications, and can be formed on the surface of any base material such as metal and plastics, and if the base material has excellent workability, a photocatalyst film can be formed by pre-coating. An object of the present invention is to provide a film and a method for forming the film.

[0011]

In order to achieve the above object, a photocatalytic film having deodorant, antibacterial and antifungal functions and excellent in processability and light resistance according to the present invention is represented by the formula RSi
A trifunctional silane represented by (X) ₃ (wherein R is a hydrocarbon group comprising an alkyl group, a phenyl group or a vinyl group, and X is an alkoxyl group or a halogen);
a hydrolysis / polycondensate with a tetrafunctional silane represented by i (X) ₄ (wherein X is an alkoxyl group or a halogen), titanium dioxide particles as a photocatalyst,
It is characterized by comprising silver as a fungicide and copper as an antibacterial agent.

Next, the method for forming a photocatalytic film according to the present invention is based on the formula RSi (X) _{3 wherein} R is a hydrocarbon group comprising an alkyl group, a phenyl group or a vinyl group, and X is an alkoxyl group or a halogen. ) And a tetrafunctional silane represented by the formula Si (X) ₄ (wherein X is an alkoxyl group or a halogen) is reacted with an alcohol or other organic solvent, water In the presence of an acid catalyst, a silver salt as an antibacterial agent and a fungicide, and a copper salt as an antibacterial agent, hydrolysis and polycondensation are performed to form a photocatalyst film-forming sol. Mixed with titanium dioxide particles as a photocatalyst, or mixed with titanium dioxide particles from the start of the reaction of the silane compound, coated with a titanium dioxide particle-containing sol on a substrate such as a metal plate, and dried, or Be heat treated after drying further 500 ° C. below the temperature is characterized in.

[0013]

Next, an embodiment of the present invention will be described.

First, the photocatalytic film having deodorizing, antibacterial and fungicidal functions and excellent in processability and light resistance according to the present invention comprises titanium dioxide, trifunctional silane and tetrafunctional silane, an antibacterial agent and fungicide. It contains silver as an agent and copper as an antibacterial agent.

The titanium dioxide used in the present invention may be prepared by any method such as particles prepared by an industrial method such as a sulfuric acid method and a chlorine method or particles obtained by a hydrothermal method or a sol-gel method. Is used, and the state of the particles may be either a powder or a state in which the powder is dispersed in a liquid.

In the sulfuric acid method and the chlorine method, titanium dioxide for a pigment having a primary particle diameter of about 0.2 to 0.3 μm and fine particle titanium dioxide having a primary particle diameter of less than 100 nm are obtained depending on the preparation conditions. Particulate titanium dioxide prepared by a chlorine method having small particles and large specific surface area is particularly preferred.

The crystal form of titanium dioxide industrially prepared is rutile type, anatase type, or a mixture of rutile type and anatase type. In the hydrothermal method, brookite type crystals may be precipitated. In the present invention, any crystalline titanium dioxide particles can be used, but in some cases, amorphous titanium oxide may be contained. The crystal form is preferably an anatase type or a mixture of a rutile type and an anatase type, and more preferably an anatase type having a high quantum efficiency in an amount of 30% by weight or more in a crystal component.

Titanium dioxide is added in a suitable amount of not more than 80% by weight in the film concentration according to the required film characteristics. When the titanium dioxide particle concentration is low, the photocatalytic effect is small and the titanium dioxide particle concentration is low. Since the workability of the film is inferior when it is high, the titanium dioxide concentration is preferably 5 to 60% by weight in the concentration in the film.

In the above, the trifunctional silane used in the present invention has a formula RSi (X) ₃ (where R is an alkyl group,
A hydrocarbon group comprising a phenyl group or a vinyl group, and X is an alkoxyl group or a halogen).

Specifically, methyltriethoxysilane,
Ethyl triethoxy silane, phenyl triethoxy silane, vinyl triethoxy silane, methyl trimethoxy silane, methyl trichloro silane, ethyl trichloro silane, vinyl trichloro silane and the like are used, and at least one kind is used.

The tetrafunctional silane used in the present invention has the formula Si
(X) _{4 wherein} X is an alkoxyl group or a halogen.

Specifically, tetraethoxysilane, tetramethoxysilane, tetrachlorosilane and the like can be mentioned, and at least one kind is used.

In the present invention, a mixture obtained by mixing the above-mentioned trifunctional silane and tetrafunctional silane and then subjecting them to hydrolysis and polycondensation is used as a binder.
A product obtained by hydrolyzing and polycondensing a functional silane, or a product obtained by mixing and hydrolyzing and polycondensing an oligomer of these silane compounds may be used.

The mixing ratio of trifunctional silane and tetrafunctional silane used in the present invention is trifunctional silane: tetrafunctional silane = x: (1
When expressed by the molar ratio of -x), 0.3 ≦ x <0.7, and preferably 0.4 ≦ x ≦ 0.6. In addition, when using the oligomer of the silane compound as a raw material of the binder,
The above molar ratio corresponds to a monomer conversion value. Here, the reason for limiting the range of x as described above is that if x is too small,
When R (hydrocarbon group) is reduced in the film, the processability of the film is reduced. When x is too large, when the surface of the titanium dioxide particles is hydrophilic, the sol containing the binder generated from the silane compound is used. This is because the dispersibility of the titanium dioxide particles is reduced.

The silver salt and copper salt used in the present invention are:
Although not particularly limited, for example, silver nitrate, silver sulfate, copper nitrate,
Examples include copper sulfate, cuprous chloride, cupric chloride, and copper carbonate. Among these, at least one kind of silver salt and copper salt is used.

The state of the metal of the silver salt and the copper salt in the photocatalytic film according to the present invention is unknown, but contains at least silver ions and / or metallic silver as a silver component,
In addition, it is believed that silver oxide may also be included. Further, at least copper ions and / or
Or, it may contain metallic copper and may further contain copper oxide. In the prepared film, silver ions and / or metallic silver act as antibacterial agents and fungicides, and copper ions and / or metallic copper act as antibacterial agents.

In the above composition, the silver salt is 0.01 to 5% by weight of titanium dioxide in terms of metallic silver, and the copper salt is
0.1-40% by weight of titanium dioxide is added in terms of metallic copper.

As described above, the silver salt and the copper salt are added simultaneously as the metal salt. When only the silver salt is added, the antibacterial and antifungal properties are sufficient, but the film is fired or used during use. When only the copper salt is added while the color changes,
This is because, although the discoloration is small and the antibacterial property is obtained when the film is baked or used, a sufficient antifungal effect cannot be obtained.

The reason why the addition amount of the silver salt is limited as described above is that if the addition amount is less than the lower limit, the antifungal effect is not sufficiently exhibited, and if the addition amount is more than the upper limit, the discoloration at the time of firing and use of the film. Is large.

The reason why the addition amount of the copper salt is limited as described above is that if the addition amount is less than the lower limit, the discoloration during the baking or use of the film due to the addition of the silver salt cannot be suppressed, and the addition amount is larger than the upper limit. This is because, when added, the discoloration during the baking or use of the film due to the addition of the copper salt itself increases.

As a raw material of the photocatalyst of the present invention, it is preferable to add aluminum hydroxide in order to improve the bonding strength and heat resistance of the film. If too much aluminum hydroxide is added, the proportion of titanium dioxide in the film will be small and the photocatalytic effect will be reduced, so aluminum hydroxide is contained in a proportion of 0 to 50% by weight with respect to titanium dioxide. Is preferred.

The thickness of the photocatalytic film according to the present invention is:
It is preferably from 0.05 to 5 μm.

Next, the method for forming a photocatalytic film of the present invention comprises the preparation of a sol for forming a photocatalytic film and the formation of a film.

Preparation of Sol for Forming Photocatalytic Film The sol for forming a photocatalytic film in the present invention is obtained by mixing titanium dioxide particles, trifunctional silane and tetrafunctional silane with alcohol or other organic solvent, water, acid catalyst, silver salt, And a copper salt are mixed and stirred at a predetermined ratio. In addition, in addition to the above-mentioned raw materials, it is preferable to add aluminum hydroxide in order to improve the bonding strength and heat resistance of the film.

Here, as the acid catalyst, inorganic acids such as sulfuric acid, nitric acid and hydrochloric acid, and organic acids such as acetic acid and oxalic acid are used.

The trifunctional silane and the tetrafunctional silane, which are the raw materials of the titanium dioxide binder, may be hydrolyzed and polycondensed, or may be used by mixing oligomers of these silane compounds. May be added at any time before or after the reaction of the silane.

Among the above sol raw materials, titanium dioxide, silver salt,
The ratio of raw materials other than copper salt and aluminum hydroxide is 3
Functional silane: tetrafunctional silane: alcohol or other organic solvent: water: acid catalyst = x: (1-x): y: z: a
When expressed as a molar ratio, the values of x, y, z, and a are each 0.1.
3 ≦ x <0.7, 0.5 ≦ y ≦ 1000, 0.5 ≦ z ≦
1000, 0.00001 ≦ a ≦ 1.

In the above composition, the value of x is as described above. If y is less than 0.5, it is difficult to disperse the particles, and if y exceeds 1000, it is difficult to form a uniform film because the solid component concentration of the prepared sol for forming a photocatalytic film is too low. It is not preferable.
On the other hand, if z is less than 0.5, the hydrolysis of the silane takes a long time, and if z exceeds 1000, the sol loses fluidity and may gel, which is not preferable. If a is less than 0.00001, the progress of the hydrolysis reaction of the silane becomes slow, and if a exceeds 1, the reaction proceeds too fast, and the period during which the sol for forming a photocatalytic film can be uniformly applied becomes short. Is not preferred.

The method for producing titanium dioxide used for preparing the sol for forming a photocatalytic film is not particularly limited, but fine particle titanium dioxide prepared by a chlorine method having a small primary particle and a large specific surface area is particularly preferred.

When titanium dioxide particles dispersed in a liquid are used, the liquid of the dispersion medium is also included in the above composition.

As the titanium dioxide used for preparing the sol for forming a photocatalytic film, particles of any crystal form can be used, and amorphous titanium oxide may be contained. Alternatively, a mixture of rutile type and anatase type is preferable.
More preferred.

Titanium dioxide is added in a suitable amount of not more than 80% by weight in the film concentration according to the required film characteristics. When the titanium dioxide particle concentration is low, the photocatalytic effect is small and the titanium dioxide particle concentration is low. Since the workability of the film is inferior when it is high, the titanium dioxide concentration is preferably 5 to 60% by weight in the concentration in the film.

In the above composition, Si1 in silane was used.
When the average number of R (hydrocarbon groups) per unit is in the range of 0.3 or more and less than 0.7, the above 3 used in the present invention is used.
A part of the composition of the functional silane is represented by the general formula R ₂ Si (X)
_{2 wherein} R is a hydrocarbon group comprising an alkyl group, a phenyl group or a vinyl group, and X is an alkoxyl group or a halogen.

In the present invention, the sol for forming a photocatalytic film is applied to a base material such as a metal plate, a panel, a tile, and a plastics directly or via a barrier layer. The application method is
Any method such as dip coating, spray coating, bar coating, and roll coating can be used.

The photocatalyst film can be obtained by drying the substrate coated with the sol for forming a photocatalyst film at a temperature of room temperature or higher. When forming a film in a short time,
In addition to drying, heat treatment may be performed at 500 ° C. or less.
When heat-treated at 0 to 500 ° C. for a long time, R (hydrocarbon group) bonded to the Si atom is calcined and desorbed, and the flexibility of the film is reduced. .

The thickness of the photocatalyst film is not particularly limited, but if the film thickness is less than 0.05 μm, it is difficult to form a defect-free film. Since there is no improvement and it is uneconomical, the film thickness is preferably 0.05 to 5 μm. However,
In the case where titanium dioxide is used also for the function of shielding ultraviolet rays, a film thickness of 5 μm or more may be used.

In the above film formation, when the substrate is plastics, the substrate is decomposed by titanium dioxide. Therefore, a barrier layer is generally provided between the substrate and the photocatalytic film. In the case where the titanium dioxide particles in the coating are few in contact with the substrate and no chalking occurs in actual use, the barrier layer may not be provided.

The production of the photocatalytic film according to the present invention comprises the preparation of a photocatalytic sol and the preparation of the film.

When the photocatalytic film is applied to the plastics substrate, a barrier is provided between the plastics and the film containing titanium dioxide to prevent the plastics from directly coming into contact with titanium dioxide and being decomposed. Provide a layer.
Further, when the substrate is soda lime glass, a barrier layer is provided to prevent sodium from diffusing into the photocatalyst film when the photocatalytic film is baked and the photocatalytic activity is reduced.

As the above-mentioned barrier layer, inorganic substances such as silicon dioxide and amorphous titanium dioxide can be mainly used, and Japanese Patent Application No. 10-18363 previously proposed by the present inventors.
The base film for photocatalyst film described in No. 2 is an inorganic-organic composite having irregularities on the surface, so that the unevenness of the surface can improve the adhesion of the photocatalytic film and be excellent in workability. Therefore, it can be suitably used as a barrier layer of the photocatalyst film of the present invention, and is particularly suitable when workability is required.

In the above description, the photocatalytic film according to the present invention has excellent processability because R (hydrocarbon group) bonded to Si derived from trifunctional silane remains in the film and flexibility. Because it gives Further, the photocatalytic film according to the present invention is excellent in light resistance because the organic group component composed of R in the film is smaller than the inorganic skeleton component composed of Si—O—Si component. This is because even if the components are oxidatively decomposed by the photocatalytic effect of titanium dioxide, most of the binder in the coating consists of Si—O—Si components that are not decomposed by the photocatalytic effect of titanium dioxide, and no chalking occurs.

The photocatalyst film according to the present invention is excellent in workability and light resistance, and has excellent deodorizing, antibacterial and antifungal functions under both light irradiation and no light environment. It can withstand use.

Further, the photocatalytic film according to the present invention has a small discoloration when the film is baked or used, so that it can be suitably used by applying it to a substrate such as a panel material or the like which needs to maintain its beautiful appearance. .

When the photocatalyst film of the present invention is applied to a substrate such as a panel surface material and irradiated with light, the photocatalytic effect of titanium oxide oxidizes and decomposes harmful substances such as odor components.
The air can be cleaned. Further, since the photocatalyst film according to the present invention is mainly composed of inorganic components, for example, when the photocatalyst film according to the present invention is applied to walls or fixtures of a kitchen or the like, dirt hardly adheres, and dirt such as seasonings remaining after washing with water or the like. Can also be oxidatively decomposed by the photocatalytic effect, so that the beauty can be maintained for a long period of time.

[0055]

Next, examples of the present invention will be described together with comparative examples.

Example 1 As a base material, a panel surface material having a coating film mainly composed of polyester on an aluminum surface was prepared. First, an undercoat film for a photocatalyst film was formed on the surface of the substrate as follows.

That is, methyltriethoxysilane,
2-propanol, water, hydrochloric acid, and SiO ₂ particles having a particle size of 0.01 to 0.02 μm dispersed in 2-propanol were prepared as raw materials. In addition, ₂ -propanol in which SiO ₂ particles were dispersed was used as a part of the solvent. The molar ratio of methyltriethoxysilane, solvent (2-propanol), water and hydrochloric acid is 1: 5: 4: 0.00.
5. Mix the raw materials so that the particle concentration becomes 10% by weight,
A sol was obtained by hydrolysis and condensation polymerization of methyltriethoxysilane. Then, a panel surface material in which a coating mainly composed of polyester is applied to the aluminum surface is immersed in the sol, pulled up at a pulling speed of 2 mm / sec, dried, and then heat-treated at 200 ° C. for 5 minutes, and then subjected to heat treatment at 200 ° C. for 5 minutes. A 0.6 μm-thick base film for a photocatalyst film was formed on a panel surface material provided with a film mainly composed of polyester.

Next, a photocatalytic film was formed on the underlayer film by the following method.

Titanium dioxide (trade name: P-25, manufactured by Nippon Aerosil Co., Ltd.), and other raw materials such as methyltriethoxysilane, tetraethoxysilane, 2-propanol, water, nitric acid, aluminum hydroxide, and copper nitrate trihydrate ,
Silver nitrate was prepared. These ratios are: methyltriethoxysilane: tetraethoxysilane: 2-propanol:
Water: nitric acid = 0.5: 0.5: 5: 4: 0.005 (molar ratio) (water includes water of hydration of copper nitrate), titanium dioxide concentration 5% by weight, aluminum hydroxide concentration 1% by weight, a copper nitrate concentration of 2% by weight (concentration excluding water of hydration) and a silver nitrate concentration of 0.1% by weight were mixed and stirred to prepare a photocatalyst film forming sol.

Next, the surface material of the panel with a base film is immersed in the sol, pulled up at a lifting speed of 2 mm / sec, dried at room temperature for 5 minutes, and heat-treated at 200 ° C. for 5 minutes to form a photocatalytic film. did. When the cross section of the obtained photocatalytic film was observed with a scanning electron microscope, the film thickness was 0.5
μm.

Example 2 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Example 1 was followed except that the silver nitrate concentration in the sol was 0.075% by weight.
A photocatalytic film was formed on the surface material of the panel with a base film in the same manner as described above. The thickness of the obtained photocatalyst film was 0.5 μm.

Example 3 An underlayer for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Then, a photocatalytic film was formed on the surface material of the panel with the undercoating film in the same manner as in Example 1 except that the concentration of silver nitrate in the sol was 0.05% by weight. The thickness of the obtained photocatalyst film was 0.5 μm.

Example 4 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Example 1 was followed except that the silver nitrate concentration in the sol was 0.025% by weight.
A photocatalytic film was formed on the surface material of the panel with a base film in the same manner as described above. The thickness of the obtained photocatalyst film was 0.5 μm.

Example 5 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalyst film was formed on the surface material of the undercoated film panel in the same manner as in Example 3 except that the heat treatment temperature was 100 ° C. The thickness of the obtained photocatalyst film was 0.5 μm.

Example 6 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalytic film was formed on the surface material of the panel with the undercoating film in the same manner as in Example 3 except that drying was performed for 24 hours without performing heat treatment. The thickness of the obtained photocatalyst film was 0.5 μm.

Example 7 A base film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalytic film was formed on the surface material of the panel with the undercoating film in the same manner as in Example 4 except that the concentration of copper nitrate in the sol was 1% by weight. The thickness of the obtained photocatalyst film was 0.5 μm.

Comparative Example 1 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalytic film was formed on the surface material of the panel with the undercoating film in the same manner as in Example 5 except that copper nitrate was not added to the sol. The thickness of the obtained photocatalyst film was 0.5 μm.

Comparative Example 2 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalytic film was formed on the surface material of the panel with a base film in the same manner as in Example 5 except that silver nitrate was not added to the sol. The thickness of the obtained photocatalyst film was 0.5 μm.

Comparative Example 3 An undercoat film for a photocatalytic film was formed on the same panel surface material as in Example 1 by the same method as in Example 1. Next, a photocatalytic film was formed on the surface material of the panel with the undercoating film in the same manner as in Example 5 except that silver nitrate and copper nitrate were not added to the sol. The thickness of the obtained photocatalyst film was 0.5 μm.

Evaluation Tests The photocatalyst films obtained in the above Examples and Comparative Examples were subjected to a bending resistance (workability) test, a discoloration test during heat treatment of the film, a light resistance test, an antibacterial test and a deodorant test.

First, the bending resistance (workability) test was performed according to JIS.
According to the method of K5400, a mandrel having a diameter of 2 mm is used.
It was evaluated by bending at 80 ° and visually checking for cracks or peeling. Table 1 shows the results of the obtained bending resistance test.
Are shown together.

Next, the discoloration test at the time of heat treatment of the film was carried out by measuring the color difference ΔE in the Lab system of the base material before and after the heat treatment of the photocatalytic film in Examples and Comparative Examples using a color tester SC-3-CH manufactured by Suga Test Instruments Co., Ltd. And evaluated by using Note that, in Example 6, the test was not performed because the sample was dried for 24 hours without heat treatment. The results of the discoloration test during the heat treatment of the obtained film are summarized in Table 1 below.

Next, the light resistance test was conducted according to JIS B775.
After irradiating the substrate coated with the photocatalyst with ultraviolet rays for 300 hours using a 1-specified ultraviolet carbon arc lamp type light resistance tester, it is checked whether or not chalking has occurred on the coating. The color difference ΔE in the system was measured using a color tester SC- manufactured by Suga Test Instruments Co., Ltd.
It measured and evaluated using 3-CH form. The results of the obtained light resistance test are summarized in Table 1 below.

The antibacterial activity test was performed by using Escherichia coil (Escherichia coil).
IFO 3972), black river (Cladosporium cladospori)
oides IFO 6348). As for the bacterial solution, for E. coli, a test bacterial solution pre-cultured for 16 to 24 hours on a normal agar medium at 37 ° C.
The cells cultured for 6 to 20 hours are uniformly dispersed and dispersed in a phosphate buffer, and the number of cells per ml is 2.0 × 10 ^{5 to} 1.0 ×
Prepared to be 10 ⁶ ,
After culturing on a potato dextrose agar medium at 25 ° C. for 7 to 10 days, the spores (conidia) are suspended in a 0.005% sodium dioctyl sulfosuccinate solution, filtered with gauze, and the number of bacteria per ml is 2.0 ×. 10 ^{5 to} 1.0 ×
10 ⁶ become so prepared, the substrate coated with the photocatalyst film on the outermost surface further after coating a base film (size: 5 cm ×
5 cm) was wiped lightly with absorbent cotton previously impregnated with 99.5% ethanol, and then air-dried to obtain a sample.

1 ml of the bacterial solution was added to the surface of each sample. These were stored under irradiation of a neutral white fluorescent lamp or completely shielded from light, and the bacteria were stored at 35 ° C and the mold at 25 ° C. When irradiating light with a fluorescent lamp, the test surface should be 10
The irradiation position was adjusted to be 00 lux. The same test was performed using a polyethylene film as a control sample.
After 4 hours, the surviving bacteria were washed out from the sample with an SCDLP medium, and the viable cell count of the washed solution was measured using a standard agar medium for Escherichia coli and an agar plate culture method using E. coli for 35 days at 35 ° C. (Incubation at 25 ° C. for 7 days) and converted to one sample. The measurement immediately after the inoculation was performed on a control sample. The results of the antibacterial activity test are shown in Table 2 below.

In the deodorizing test, a substrate (effective area 200 cm ² ) coated with a photocatalytic film was fixed in a polyvinyl fluoride bag, the bag was sealed by heat sealing, and then 3 liters of air containing 100 ppm of ammonia. And irradiating it with a 20 W black light from above, and measuring the gas concentration in the bag using a gas detector tube 24 hours after the start of the light irradiation, and measuring the ammonia removal rate% after 24 hours. did.

The distance between the substrate and the black light is 30.
cm, and the gas concentration after light irradiation was measured in the same manner without inserting the substrate coated with the photocatalytic film, and this was used as a blank test. Moreover, the deodorizing test of the film was performed in the same manner as described above except that the light was completely blocked. The results of the deodorization test of the formed film are shown in Table 3 below.

[0078]

[Table 1]

[Table 2]

[Table 3] As is clear from Tables 1 to 3, the photocatalyst films according to Examples 1 to 7 are excellent in bending resistance (workability) and light resistance, and can be obtained under any environment under light irradiation and without light. It had excellent deodorant, antibacterial, and fungicidal functions. Further, the substrates of Examples 1 to 5 and 7 in which the photocatalytic film was heat-treated had very little discoloration before and after the heat treatment. It should be noted that when light was applied, a photocatalytic effect was exerted, so that the results were more excellent in deodorizing power than when no light was applied. On the other hand, the photocatalytic film according to Comparative Example 1 was excellent in bending resistance (workability), deodorant, antibacterial, and fungicidal effects, and although no chalking occurred after the light resistance test, copper salt was added. Since the silver salt was added without performing the test, the color difference before and after the light resistance test and the color difference before and after the film heat treatment were increased. The photocatalytic film according to Comparative Example 2 is excellent in bending resistance (workability), light resistance, deodorant, and antibacterial effect, and has a small color difference before and after the heat treatment of the film. However, the copper salt is added without adding the silver salt. As a result, almost no antifungal effect was observed. The photocatalytic film according to Comparative Example 3 is excellent in bending resistance (workability), light resistance, and deodorizing effect, and has a small color difference before and after heat treatment of the film. Under the test conditions, little antibacterial and antifungal effect was observed.

In the deodorizing test, in the blank test, the removal rate of ammonia was 34%. This is considered to be because ammonia was adsorbed on the bag used for the test.

[0080]

As described above, the photocatalytic film according to the present invention has the formula RSi (X) ₃ (where R is a hydrocarbon group comprising an alkyl group, a phenyl group or a vinyl group, X is an alkoxyl group, or A trifunctional silane represented by the formula: Si (X) _{4 wherein} X is an alkoxyl group;
Or a halogenated tetrafunctional silane, a titanium dioxide particle as a photocatalyst, silver as an antibacterial agent / antifungal agent, and copper as an antibacterial agent. It has excellent workability and light resistance, and has excellent deodorant, antibacterial, and fungicidal functions under both light-irradiated and non-light environments, so it can withstand use in any environment. . In addition, the photocatalytic film according to the present invention has an effect that it can be suitably used by applying it to a base material for which it is necessary to maintain a beautiful appearance such as a panel material, since the discoloration is small at the time of film baking or at the time of use. Play.

Further, as described above, the method for forming a photocatalytic film according to the present invention employs the formula RSi (X) ₃ (where R is a hydrocarbon group comprising an alkyl group, a phenyl group or a vinyl group, and X is an alkoxyl group Or a halogen), and a tetrafunctional silane represented by the formula Si (X) ₄ (where X is an alkoxyl group or a halogen), solvent,
In the presence of water, an acid catalyst, a silver salt as an antibacterial agent and a fungicide, and a copper salt as an antibacterial agent, hydrolysis and polycondensation are performed to form a sol for forming a photocatalytic film. Is mixed with titanium dioxide particles as a photocatalyst, or titanium dioxide particles are mixed from the start of the reaction of the silane compound, and a sol containing titanium dioxide particles is applied to a base material such as a metal plate and dried or dried. After 500 ° C
It is characterized by being subjected to a heat treatment at the following temperature, and according to the method of the present invention, it has excellent workability and light resistance and deodorizes,
Photocatalytic film with antibacterial and antifungal effect
It can be formed on the surface of any base material such as plastics, and if the base material itself has good workability, there is an effect that a photocatalytic film can be formed by precoating.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) A01N 59/16 AJA A01N 59/16 AJAZ 59/20 59/20 Z C08K 3/08 C08K 3/08 3 / 22 3/22 C08L 83/04 C08L 83/04 // C01G 23/047 C01G 23/047 (72) Inventor Kiyoshi Tada F-term (reference) 4G047 CA05 in Showa Aluminum Co., Ltd. 6, 224 Kaiyamacho, Sakai City CB06 CC03 4G069 AA04 AA08 BA01A BA01B BA04A BA04B BA48A BB02A BB06A BB06B BC31A BC31B BC32A BC32B BD05A BD05B BE01A BE01B BE01C CA01 CA17 DA06 EA20 FA06 FC08 4H011 AA02 DEA01 CB0 FD187 GH00 HA04

Claims (16)

[Claims] A compound of the formula RSi (X) _{3 wherein} R is an alkyl, phenyl or vinyl hydrocarbon group;
Hydrolysis of a trifunctional silane represented by X (X is an alkoxyl group or halogen) and a tetrafunctional silane represented by the formula Si (X) ₄ (X is an alkoxyl group or halogen)・ Contains polycondensate, titanium dioxide particles as a photocatalyst, silver as an antibacterial agent / antifungal agent, and copper as an antibacterial agent, has deodorant, antibacterial, and antifungal functions, and has processability and light resistance. Photocatalytic film with excellent properties. 2. The photocatalytic film according to claim 1, wherein the concentration of titanium dioxide in the film is 5 to 80% by weight. 3. The photocatalytic film according to claim 1, wherein the titanium dioxide contains at least one type selected from the group consisting of anatase type, rutile type, and brookite type as a crystal form. 4. The photocatalytic film according to claim 3, further comprising an amorphous titanium oxide. 5. The method according to claim 1, wherein the crystalline form of titanium dioxide contains anatase type, or rutile type and anatase type, and at least 30% by weight of anatase type is contained in the crystalline component of titanium dioxide. Item 7. The photocatalytic film according to Item 1. 6. Silver ions and / or silver components in the coating.
Or metallic silver, and the concentration of silver ion, metallic silver and / or silver compound is 0.1% of titanium dioxide in terms of metallic silver.
0.1 to 5% by weight, and contains copper ions and / or metallic copper as a copper component in the film, and the concentration of copper ions, metallic copper and / or copper compound is 0.1 to 40% of titanium dioxide in terms of metallic copper. The photocatalyst film according to claim 1, which is a percentage by weight. 7. The photocatalytic film according to claim 1, further comprising 0 to 50% by weight of aluminum hydroxide with respect to titanium dioxide. 8. The photocatalyst film according to claim 1, wherein the film thickness is 0.05 to 5 μm. 9. A compound of the formula RSi (X) _{3 wherein} R is an alkyl, phenyl or vinyl hydrocarbon group;
X is an alkoxyl group or a halogen) and a tetrafunctional silane of the formula Si (X) ₄ (wherein X is an alkoxyl group or a halogen), Or other organic solvents, water,
In the presence of an acid catalyst, a silver salt as an antibacterial agent and a fungicide, and a copper salt as an antibacterial agent, hydrolysis and polycondensation are performed to form a sol for forming a photocatalytic film, and the sol for forming a photocatalytic film is used as a photocatalyst. Or a mixture of titanium dioxide particles from the beginning of the reaction of the silane compound, apply a sol containing titanium dioxide particles to a base material such as a metal plate, and dry or, after drying, further 500 A method for forming a photocatalytic film having deodorizing, antibacterial, and antifungal functions, and having excellent workability and light resistance, characterized by being heat-treated at a temperature of not more than ℃. 10. The ratio of a raw material of a sol for forming a photocatalytic film other than titanium dioxide, a silver salt and a copper salt to trifunctional silane:
Tetrafunctional silane: alcohol or other organic solvent:
Water: acid catalyst = x: (1-x): y: z: When expressed as a molar ratio, the values of x, y, z, a are respectively 0.3 ≦ x <0.
7, 0.5 ≦ y ≦ 1000, 0.5 ≦ z ≦ 1000,
The method for forming a photocatalytic film according to claim 9, wherein 0.00001≤a≤1. 11. The method for forming a photocatalytic film according to claim 9, wherein the crystalline form of titanium dioxide includes at least one type selected from the group consisting of anatase type, rutile type, and brookite type. 12. The method for forming a photocatalytic film according to claim 9, further comprising amorphous titanium oxide. 13. The crystal form of titanium dioxide comprising anatase type, or rutile type and anatase type, and at least 30% by weight of anatase type in a crystal component of titanium dioxide. Item 10. The method for forming a photocatalytic film according to Item 9. 14. The silver salt concentration is 0.01 to 5% by weight of titanium dioxide in terms of metallic silver, and the copper salt concentration is 0.1 to 40% by weight of titanium dioxide in terms of metallic copper. Item 10. The method for forming a photocatalytic film according to Item 9. 15. The method for forming a photocatalytic film according to claim 9, further comprising 0 to 50% by weight of aluminum hydroxide with respect to titanium dioxide. 16. The method for forming a photocatalytic film according to claim 9, wherein the heat treatment temperature is 300 ° C. or lower.