JP3514943B2 - Antifouling method and antifouling article using photocatalyst - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photocatalyst film that catalyzes the decomposition of organic substances, an antifouling method using the film, and an article provided with the film.

[0002]

_2. Description of the Related Art In recent years, attention has been paid to decomposition of organic substances and antibacterial deodorants using TiO ₂ photocatalysts. This is as described in New Ceramics (1996) No. 2,55,
One using an oxidation-reduction reaction of the semiconductor photocatalyst, TiO ₂
It is proposed that a thin film is molded in a ceramic style.

As a film forming method for these photocatalysts, there is a chemical method such as a sol-gel method. This is to obtain a photocatalyst film by applying the raw material composition onto a substrate with a simple apparatus such as spin coating or spraying and heating the substrate at a temperature of usually several hundreds of degrees Celsius. Since anatase type TiO ₂ crystal is effective for antibacterial deodorization, it has been reported that crystallization of TiO ₂ is effective for function expression (International Publication No. WO94 / 11092, WO95 / 15816). .
In addition, it has been reported that TiO ₂ is added with V, Fe, etc. to improve performance (W. Choi, A. Termin., MRHo.
ffmann, J. Phys. Chem., 98, 13669-13679 (1994)).

[0004]

TiO ₂ has a function as a photocatalyst, and has a function of decomposing organic substances and nitrogen oxides and an antibacterial and deodorant effect. Its function is semiconductor, Ti
This is due to electrons and holes generated when O ₂ is irradiated with light, especially ultraviolet rays. When TiO ₂ which is a semiconductor is irradiated with light having an energy larger than the band gap, it produces electrons and holes. The generated electrons and holes decompose water adsorbed on the TiO ₂ surface to generate H radicals and OH radicals.
By reacting the OH radical with an organic substance, the organic substance can be decomposed. Therefore, by using the above technique, it is possible to obtain a material effective for environmental purification by decomposing organic substances as an antibacterial / deodorant.

However, such a photocatalyst can decompose and remove fine foreign matter, but if relatively large foreign matter such as dust adheres, it is difficult to remove it. Therefore, dust will cover the surface,
As a result, the light irradiation amount on the photocatalyst is reduced, and the performance thereof is deteriorated.

To solve this problem, the international publication number WO
As reported in International Publication No. 96/129375, a superhydrophilic photocatalyst has been proposed which can easily remove stains such as inorganic substances with water by improving hydrophilicity. This superhydrophilic photocatalyst is effective when used in an environment where water can be supplied. However, when used in an environment where water cannot be supplied, for example, indoors, electric appliances, etc., it is difficult to wash off the adhered dust and the like.

Therefore, the present invention provides an antifouling film capable of decomposing organic substances with a photocatalyst and having an excellent antifouling effect effective against dust and the like, an antifouling method using the film, and the film. An object of the present invention is to provide an article to be provided.

[0008]

In order to achieve the above object, in the present invention, the surface resistance value of a photocatalytic film containing a photocatalyst that catalyzes the decomposition of organic substances is set to 10 ⁹ Ω / □ or less by using a conductor. An antifouling method for catalyzing the decomposition of organic substances and preventing the adhesion of foreign matter, and an antifouling film comprising a photocatalyst film containing a photocatalyst for catalyzing the decomposition of organic substances, the surface resistance value of which is 10 ⁹ An antifouling film having an Ω / □ or less is provided.

According to the method of the present invention, fine organic matter is decomposed by a photocatalyst. In addition, since the photocatalyst film is provided with electrical conductivity (having a low surface resistance value), charging is prevented, and therefore foreign matter such as dust (organic matter / inorganic matter) can be prevented from being attracted by static electricity. Therefore, according to the present invention, not only can organic substances once attached be decomposed and removed, but also attachment of charged foreign matter can be avoided. In the present invention, since the surface of the photocatalyst film is not covered with foreign matter such as dust even after long-term use, sufficient light is supplied to the photocatalyst. Therefore, even if it is used for a long time, the photocatalytic activity does not decrease.

The surface resistance of the photocatalytic film is 10 ⁹ Ω.
When it is / square or less, an effect sufficient to prevent the adhesion of dust is obtained, and it is particularly preferably 10 ⁴ Ω / square or less.

Further, according to the present invention, an article having a photocatalyst film containing a photocatalyst for catalyzing the decomposition of organic matter is provided as an article having a function of decomposing organic matter and preventing adhesion of foreign matter due to static electricity. By preventing static electricity, an antifouling article having an antistatic mechanism for preventing adhesion of dust is provided. Here, in the antistatic mechanism, it is desirable that the surface resistance value of the photocatalyst film be 10 ⁹ Ω / □ or less.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, by preventing the photocatalyst film from being charged, the performance of the photocatalyst (that is, the performance of decomposing organic matter) is improved, and the adhesion of foreign matter such as dust floating in the air is prevented. It can prevent and provide higher performance antifouling function. Further, in the present invention, since adhesion of dust and the like is avoided, the performance can be maintained without reducing the irradiation amount of light to the photocatalyst even when used for a long time.

As described above, the antistatic mechanism is made of a conductor and serves to reduce the surface resistance of the photocatalytic film. As a conductor for preventing electrification, Sn, In, Ag, Pd and / or Cu, or an alloy thereof is used so as not to deteriorate the activity of the photocatalyst, or
ATO (Sb-added SnO ₂ ) and / or ITO (S
It is desirable to use a conductive oxide such as n-doped In ₂ O ₃ ). ATO is about 2-10 mol% of S in SnO _2.
b ₂ O ₅ is a conductor added, and ITO is a conductor obtained by adding about 8 to 12 mol% SnO ₂ to In ₂ O ₃ .

The antistatic property may be realized by dispersing conductive fine particles made of a conductor in the photocatalyst film to impart conductivity, or by providing a conductive film.

When the conductive fine particles are dispersed in the photocatalyst film, the conductive fine particles are contained in an amount of 1 to 20% by weight based on the total weight of the photocatalyst film so that the photocatalytic activity and the film strength are not lowered while ensuring sufficient conductivity. Is desirable.

The conductive film may be the base material of the article, or may be provided between the base material and the photocatalytic film. The conductive film does not have to be in contact with the photocatalyst film, but the distance between them is preferably narrow enough to obtain the effect of lowering the surface resistance value of the photocatalyst film. In addition, the conductive film is
A film made of a conductor may be used, but a film in which conductive fine particles are dispersed may be used as long as sufficient conductivity can be secured.

As the photocatalyst film, a film made of only a photocatalyst can be used. Photocatalysts that can be used in the present invention include TiO ₂ , SrTiO ₃ , BaTiO ₃ ,
At least one of WO ₃ and SiC can be used. The photocatalyst film should be in direct contact with the outside air,
It is desirable to provide it on the outermost surface of the article.

In order to increase the reaction rate of the photocatalyst, it is desirable to increase the number of active sites. For this purpose, it is desirable to increase the surface area, that is, to make the photocatalyst into fine particles. Therefore, as the photocatalyst film, it is preferable to use a composition film consisting of photocatalyst fine particles and a binder, instead of a film consisting only of the photocatalyst. Binder (continuous phase)
As the substance, a substance that is porous, has high water absorption, does not deteriorate the activity of the photocatalyst, and is not decomposed by the photocatalyst, particularly an inorganic substance is preferable, and for example, SiO ₂ can be used. When the composition film is used as the photocatalyst film, the weight of the photocatalyst is preferably 9 times or less the weight of the binder in order to obtain sufficient film strength, and in order to obtain sufficient photocatalytic activity,
It is desirable that the weight is 5 times or more the weight of the binder.

The work of the active sites can be improved by improving the crystallinity of the photocatalyst. However, if the crystallinity is improved, the particle size increases and the surface area decreases. Therefore, the present inventors have conducted many experiments and found that the reaction rate becomes maximum when the crystallite diameter of the photocatalyst determined by X-ray is 5 to 20 nm. Even if various oxides were used as the binder for dispersing the TiO ₂ fine particles, the decomposition rate was maximized in this range.

Further, in order to obtain a practically sufficient decomposition rate, a certain amount of catalyst is required, and for that purpose, it is desirable that the thickness of the photocatalyst film be 100 nm or more.
If the film thickness exceeds 500 nm, the film may be cracked or the strength may become insufficient.
The thickness of the photocatalyst film is preferably 500 nm or less. For the conductive film, the film thickness should be 50 for the same reason.
It is desirable that the thickness be 0 nm or less. Considering the crystallite diameter of the conductive fine particles, the lower limit of the film thickness is usually 5 to 10 nm or more. In addition, the surface resistance value of the photocatalyst film is 10 ⁴ Ω / □
In order to obtain the degree, it is usually desirable to set the thickness to 30 nm or more.

As the base material, any material such as glass, ceramics (including ceramics), resin, etc. can be used as long as it can form a film on its surface. In addition,
If a flexible plastic film is used as a base material, it can be easily attached to building materials such as wall materials, window materials, and pillar materials, and curved members such as automobile front glass, etc. It is possible to obtain an easy-to-use antifouling material (article) that can be easily replaced. Therefore, in the present invention, a film including a sheet-shaped substrate containing an organic polymer compound, a conductive film, and a photocatalyst film, which are laminated in this order, is provided as an antifouling article. If a sheet of a conductive organic polymer compound is used as the base material, it is not necessary to further provide a conductive film. When using as a sticking film, use a substrate having adhesiveness, or provide a layer containing an adhesive on the surface of the front and back of the substrate on which the photocatalytic film is not formed. However, it is preferable in terms of usability.

The sheet-shaped substrate containing the organic polymer compound is not particularly limited as long as it is used for several months, and various organic resins generally used as plastic films can be used. . However, if the base material and the photocatalyst are in direct contact, if used for several months or more,
The base material itself is decomposed and the photocatalytic film is peeled off. Therefore, when used for several months or more, it is desirable to use a resin that is not easily affected by the photocatalyst, such as a siloxane resin, a silicon resin, or a fluororesin. Further, a material that is not easily affected by the photocatalyst so that the base material and the photocatalyst do not come into direct contact (for example, the above-mentioned resin or inorganic material)
The provision of a barrier layer made of is also effective for preventing peeling. The barrier layer is provided between the base material and the photocatalytic film. When a conductive film is provided, this conductive film functions as a barrier to some extent, but it is desirable to further provide a barrier layer. In this case, between the base material and the conductive film,
A barrier layer may be provided between the conductive film and the photocatalyst film.

The present inventors have found that Fe, Al and /
It was also found that the presence of Zr causes the photocatalytic activity of TiO ₂ to be lost. Therefore, in the present invention, Fe, Al,
Articles are provided that include a barrier layer containing Zr. In this way, by containing a substance that deactivates the photocatalytic activity in the barrier layer, it is possible to prevent the organic material (base material, etc.) in the lower layer from being decomposed / altered by the upper photocatalytic layer. Further, by using this deactivating substance, the barrier layer can be made thinner than before. If the conductive film contains an element that deactivates these photocatalysts,
The conductive film will also function as a high performance barrier layer. On the contrary, the barrier layer may be made to function as a conductive film for reducing the surface resistance of the photocatalytic film by dispersing the conductive fine particles in the barrier layer.

If the thickness of the barrier layer exceeds 500 nm, the film may be cracked or its strength may become insufficient. Therefore, it is desirable to set the thickness to 500 nm or less. Further, the lower limit of the film thickness is appropriately determined according to the application. For example, in the case of antibacterial purposes only, a weak catalytic action is sufficient, and therefore, the thickness is usually 20 nm or more.
Further, in the case of decomposing organic substances, nitrogen oxides, etc., a strong catalytic action is required, so it is usually set to 50 nm or more. However, even in this case, when an element for deactivating the above-mentioned photocatalytic activity is contained. The film thickness can be about 20 nm.

Examples of the antifouling article to which the present invention is applied include, in addition to the above-mentioned antifouling film, building materials (window materials such as glass plates, tiles, wall materials such as building panels, flooring materials, pillar materials, etc.). ), Interior materials (wallpaper, curtains, mirrors, etc.), automobile parts (window glass, interior parts, etc.), furniture, sanitary ware (toilet bowls, washbasins, etc.), bathtubs, sinks, etc. .

[0026]

【Example】

(Examples 1 to 5 and Comparative Examples 1 and 2) In this example, FIG.
As shown in (b), a glass plate 5 with an antistatic photocatalyst film was produced in which the substrate 1 and the conductive photocatalyst film 4 were laminated.
The conductive photocatalyst film 4 has a continuous phase 3 made of TiO ₂ which is a photocatalyst, as can be seen from the partially enlarged sectional view of FIG.
And conductive particles 2 dispersed in the continuous phase 3. The method for producing this glass plate in this example is described below.

First, in order to form the continuous phase 3 composed of TiO ₂ , 10 g of isopropoxy titanate was dissolved in 90 g of isopropanol to prepare a titania sol for forming a TiO ₂ phase. Next, Ag, Cu, Pd, A
Fine particles of TO or ITO (crystallite size determined by X-ray: 5 to 10 nm) were mixed with ethanol-propanol 2: 1.
(Volume ratio) Nonionic surfactant (1% by weight) in the mixed liquid
Was used to prepare a conductive fine particle dispersion liquid (2% by weight). Furthermore, 5 g of the above-mentioned fine particle dispersion liquid was added to 5 g of the prepared titania sol to prepare various coating liquids.

The obtained coating solution was dropped onto the entire surface of one side of the well-washed glass substrate 1 (100 mm × 100 mm × 2 mm) and spin-coated at 400 rpm to form a coating film, and then at 60 ° C. Let it dry for 5 minutes,
Furthermore, it heat-processed at 450 degreeC for 1 hour. As a result, a glass plate 5 was obtained in which the antistatic photocatalyst film 4 (film thickness 400 nm) in which the conductive fine particles 2 were dispersed in the photocatalyst film 3 was laminated on the surface of the glass substrate 1.

In addition, as a comparative example, a coating film was similarly formed by using titania sol or silica sol to which the fine particle dispersion was not added as a coating solution, and dried and heat-treated in the same manner as in the above-mentioned examples to obtain a non-conductive material. Film (film thickness 400
nm). The titania sol was prepared in the same manner as the above-mentioned preparation method. The silica sol for forming the SiO ₂ phase was prepared by dissolving 10 g of tetraethoxysilane in 90 g of isopropanol.

The surface resistance value of the obtained antistatic photocatalyst thin film 4 or non-conductive film and the stain of the film after left in the smoking room for 1 month were examined, and the results shown in Table 1 were obtained. became.

[0031]

[Table 1]

As can be seen from this table, the surface resistance value is
10 in the film in which the conductive fine particles are dispersed (Examples 1 to 5).
⁸ to 10 ⁹ Ω / □, 1 in the case of TiO ₂ only film (Comparative Example 1)
0 ¹⁰ Ω / □, 10 ^{12 for} a film containing only SiO ₂ (Comparative Example 2)
Ω / □ or more. Antistatic function has surface resistance of 1
If it is less than ⁰⁹ Ω / □, it is considered to be effective for preventing dust adhesion. Therefore, from the obtained surface resistance value, it can be seen that the sample in which the conductive fine particles are dispersed has an antistatic effect, but this effect cannot be expected in a film containing only SiO ₂ or TiO ₂ . In fact, dust was adhered to the TiO ₂ only film (Comparative Example 1) and the SiO ₂ only film (Comparative Example 2), but the antistatic photocatalytic film in which the conductive fine particles of each Example were dispersed was used. Almost no dust was attached.

On the other hand, regarding the photocatalytic properties, a film of TiO ₂ alone (Comparative Example 1) and T containing conductive particles dispersed therein were used.
No adhesion of tobacco tar was found on the iO ₂ film (Examples 1 to 5), so Examples 1 to 5 and Comparative Example 1
It is believed that any of the above membranes have effective photocatalytic properties. However, the film containing only SiO ₂ (Comparative Example 2) had no photocatalytic property and was colored yellow due to the adhesion of tar.

From the above results, the antistatic photocatalytic film formed by dispersing the conductive fine particles in the photocatalyst should not only decompose the organic matter such as the tar of the cigarette but also prevent the adhesion of the inorganic matter such as dust. It was found that the antifouling effect was superior to the conventional materials.

As the photocatalytic continuous phase 3, instead of the TiO ₂ film, SrTiO ₃ and BaTi having photocatalytic properties are used.
A glass plate 5 was prepared by forming a film of O ₃ , WO ₃ or SiC (film thickness 400 nm), and an experiment similar to that of Examples 1 to 5 was performed. As a result, Examples 1 to 5 using TiO ₂ were obtained. Similar results were obtained, and it was confirmed that these materials were also effective.

The SrTiO ₃ film was prepared by adding 100 ml of a strontium nitrate propanol solution (0.3 mol / L),
Isopropoxy titanate in propanol (0.3
mol / L) 100 ml and mixed well to prepare a solution prepared by dispersing 5 g of the above-mentioned electroconductive fine particle dispersion liquid, and spin-coating the coating liquid on the surface of the glass substrate 1. And dried at 60 ° C. for 5 minutes and then heated at 850 ° C. for 2 hours to form a film.

The BaTiO ₃ film was composed of 100 ml of a barium nitrate propanol solution (0.3 mol / L) and 100 ml of an isopropoxy titanate propanol solution (0.3 mol / L).
/ L) 100 ml and mixed well, to prepare a coating solution by dispersing 5 g of the above conductive fine particle dispersion liquid in a solution prepared by spin coating the surface of the glass substrate 1 with this coating solution. After being dried at 60 ° C. for 5 minutes, it was formed by heating at 850 ° C. for 2 hours.

The WO ₃ film was prepared by dispersing 5 g of the above conductive fine particle dispersion in 5 g of a propanol solution of tungsten nitrate (0.3 mol / L),
After being spin-coated on the surface of the glass substrate 1, it was dried at 60 ° C. for 5 minutes and further heated at 450 ° C. for 1 hour to be formed.

(Examples 6 to 10) Using the titania sol and various conductive fine particle dispersions prepared in Examples 1 to 5, as shown in FIG. 2, on the glass substrate 1 and the conductive layer 6.
A glass plate 20 with an antistatic photocatalyst film was produced in which the photocatalyst layer 7 and the photocatalyst layer 7 were laminated in this order.

First, the conductive fine particle dispersion liquid was dropped onto one of the front and back surfaces of the glass substrate 1 which was well washed similarly to the one used in Example 1, and was spin-coated at 400 rpm.
It was dried at 5 ° C. for 5 minutes to form a coating film of the conductive fine particle dispersion liquid. Next, a titania sol coating film was laminated on the obtained coating film surface by dropping titania sol and spin coating at 400 rpm. Finally, the entire laminate is 450
A heat treatment was performed at 1 ° C. for 1 hour to obtain an antistatic photocatalyst film 8 which is a laminated film including the conductive layer 6 (film thickness 400 nm) and the TiO ₂ layer 7 (film thickness 400 nm).

When the performance of the antistatic photocatalyst film 8 on the obtained glass plate 20 was evaluated in the same manner as in Examples 1 to 5, as shown in Table 2, the surface resistance of the photocatalyst layer 7 was 1.
It was 0 ³ to 10 ⁶ and was found to have an excellent antifouling effect capable of preventing coloring by dust of a cigarette and adhesion of dust, similar to Examples 1 to 5.

[0042]

[Table 2]

As a photocatalyst layer, a thin film (film thickness 400 nm) of SrTiO ₃ , BaTiO ₃ or WO ₃ having photocatalytic properties was formed instead of the TiO ₂ layer 7.
A glass plate 20 having an antistatic photocatalyst film 8 which is a laminated film was prepared in the same manner as in Examples 6 to 10, and the performance was evaluated. The same results as when using TiO ₂ were obtained, and these materials were also used. It was confirmed to be effective.

The SrTiO ₃ film was formed by using a strontium nitrate propanol solution (0.3 mol / L) 100 m.
1 and 100 ml of a propanol solution of isopropoxy titanate (0.3 mol / L) were mixed and well stirred to prepare a coating solution, which was spin-coated on the surface of the glass substrate 1 and dried at 60 ° C. for 5 minutes. , 850
It was formed by heating at 0 ° C. for 2 hours.

The BaTiO ₃ film is composed of 100 ml of a barium nitrate propanol solution (0.3 mol / L) and 100 ml of an isopropoxy titanate propanol solution (0.3 mol / L).
/ L) 100 ml, and the mixture was thoroughly stirred to prepare a coating liquid, which was applied onto the surface of the glass substrate 1 by spin coating, dried at 60 ° C. for 5 minutes, and then heated at 850 ° C. for 2 hours to form the layer.

The WO ₃ film was formed by coating the surface of the glass substrate 1 with a propanol solution of tungsten nitrate (0.3 mol / L), drying it at 60 ° C. for 5 minutes, and then heating it at 450 ° C. for 1 hour. .

(Examples 11 to 15) Up to Example 2, a substrate which can be treated at a high temperature was used, but the present invention is not limited to this, and an antistatic photocatalytic film is generally formed on a plastic surface having low heat resistance. can do. In this embodiment, PE
Using T (polyethylene terephthalate) film as the base material,
By performing a low-temperature film forming process as shown below, as shown in FIG.
A high-performance plastic film 30 with an antistatic photocatalytic thin film 13 shown in (b) was produced. Note that the conductive photocatalyst film 13 of this example has a continuous phase 10 made of SiO ₂ and TiO, which is a photocatalyst, dispersed in the continuous phase 10, as can be seen from the partially enlarged sectional view of FIG. _{The second} fine particles 11 and the conductive fine particles 12 are provided.

First, 5 g of tetraethoxysilane was added to 10
0 ml of water-ethanol-propanol (volume ratio 3: 2
7:70) Dissolved in a mixed solution, stirred at 40 ° C. for about 5 hours, and allowed to stand at room temperature for 2 weeks to prepare a SiO ₂ sol. Next, the obtained SiO ₂ sol was mixed with TiO ₂ in a weight ratio.
The amount of TiO ₂ particles was such that / SiO ₂ = 9, and water was added so that the solid content concentration was 4% by weight. Further, various conductive fine particle dispersions prepared in Example 1 were added and kneaded with a zirconia ball having a diameter of 5 mm in a 24 hr ball mill to obtain various coating liquids in which TiO ₂ fine particles and conductive fine particles were dispersed in SiO ₂ sol. Was prepared.

Finally, the obtained coating liquid was subjected to PET.
Film 9 (100 mm × 100 mm × 0.2 mm) was spin-coated and cured by irradiation with a low pressure mercury lamp (strength: 15 mW / cm ² ) at 120 ° C. for 5 minutes.
As a result, TiO ₂ fine particles 11 are contained in the SiO ₂ continuous phase 10.
And antistatic photocatalyst film 13 in which conductive particles 12 are dispersed
Plastic film 30 having (film thickness 400 nm)
Was formed. The thin film obtained on the PET film had good film quality and strength.

High-performance plastic film 30 obtained
The performance of the antistatic photocatalytic film 13 in Examples 1-5
The evaluation was performed in the same manner as in Table 3, and as shown in Table 3, the surface resistance was 10 ⁹ Ω / cm when any of the conductive fine particles was used.
It was found that it has the following excellent antifouling effect, which is the same as in Examples 1 to 5 and can prevent the coloring by the tar of the cigarette and the adhesion of dust.

[0051]

[Table 3]

As the photocatalyst fine particles 11, TiO _{2 was used.}
Examples 11 to 15 except that fine particles of SrTiO ₃ , BaTiO ₃ , WO ₃ or SiC were used instead of the fine particles.
The antistatic photocatalyst film 13 (film thickness 400n
When a high-performance plastic film 30 having m) was prepared and the performance was evaluated, the same results as those using TiO ₂ fine particles were obtained.

The SrTiO ₃ fine particles were formed as follows. That is, 100 ml of a strontium nitrate propanol solution (0.3 mol / L) and an isopropoxy titanate propanol solution (0.3 mol / L)
The solution prepared by mixing with 100 ml and stirring well,
The whole container was dried at 80 ° C. for 5 hours, then heated at 850 ° C. for 2 hours, taken out of the container and pulverized to obtain fine particles (crystallite diameter 10 nm determined by X-ray).

BaTiO ₃ fine particles are 100 ml of a barium nitrate propanol solution (0.3 mol / L).
And 100 ml of a propanol solution of isopropoxy titanate (0.3 mol / L) were mixed and well stirred to prepare a solution, which was dried with the container at 80 ° C for 5 hours, and then heated at 850 ° C for 2 hours, and then the container. And pulverized to obtain fine particles (crystallite diameter determined by X-ray: 10 nm).

WO ₃ fine particles were prepared by using a propanol solution of tungsten nitrate (0.3 mol / L) in a container at 80 ° C.
After drying for 5 hours at 850 ° C., it was heated for 2 hours at 850 ° C., taken out of the container and pulverized to obtain fine particles (crystallite diameter 10 nm determined by X-ray).

As the SiC fine particles, a commercially available product having a crystallite diameter of 10 nm determined by X-ray was purchased and used.

(Examples 16 to 20) In Examples 11 to 15, conductive fine particles were further dispersed in the film in which the photocatalyst fine particles were dispersed. In this Example, however, as shown in FIG. A high-performance plastic film 40 having an antistatic photocatalyst thin film 19, which is a laminated film of the photocatalyst layer 18 in which the above-mentioned dispersed and the conductive layer 15 in which conductive particles are dispersed, was produced.

First, in the same manner as in Examples 11 to 15, Si was used.
After preparing an O ₂ sol and adding TiO ₂ fine particles (crystallite size determined by X-ray: 5 nm) in a weight ratio of TiO ₂ / SiO ₂ = 9, the solid content concentration becomes 4% by weight. Water was added to the mixture to prepare a mixture, and zirconia balls having a diameter of 5 mm were used for kneading with a 24 hr ball mill to disperse the TiO ₂ fine particles in the SiO ₂ sol. As a result, a coating liquid for forming the photocatalyst layer 18 was obtained.

The antistatic photocatalyst thin film 19 was formed as follows. First, PET similar to that of Examples 11 to 15
The conductive fine particle dispersion liquids prepared in Examples 1 to 5 were applied to the film 9 by spin coating, dried at 60 ° C. for 5 minutes, and then the coating liquid for forming the photocatalyst layer 18 was applied onto the surface by spin coating. Finally, at 120 ° C., a low pressure mercury lamp (strength: 15 mW / cm ² ) was irradiated for 5 minutes to cure. Thereby, on the PET film 9,
A laminated film 19 of the conductive layer 15 (film thickness 400 nm) and the TiO ₂ -dispersed SiO ₂ layer (photocatalyst layer) 18 (film thickness 400 nm) was formed. The conductive fine particles 1 in the conductive layer 15
The gap ₂ was filled with SiO _2, which is the continuous phase of the upper layer 18. The thin film 19 obtained on the PET film 9 in this example had good film quality and strength.

High-performance plastic film 40 obtained
The performance of the antistatic photocatalyst film 19 in Examples 1-5
The evaluation was performed in the same manner as in Table 1. As shown in Table 4, the surface resistance of the photocatalyst layer 18 was 10 ⁹ Ω / □ or less, which is the same as in Examples 1 to 5, when any conductive fine particles were used. It was found that it has an excellent antifouling effect that can prevent the coloring by the tar of the cigarette and the adhesion of dust.

[0061]

[Table 4]

As the photocatalyst fine particles 11, TiO _{2 was used.}
Instead of the fine particles, the above-mentioned SrTiO ₃ , BaTiO ₃ , W
Example 16 except that fine particles of O ₃ or SiC were used.
~ 20, the antistatic photocatalyst film 1 which is a laminated film
A high-performance plastic film 40 including 9 is produced,
When the performance was evaluated, the same results as those using the TiO ₂ fine particles were obtained.

(Examples 21 to 24) In this example, a barrier layer was provided between the base material and the photocatalyst film so that the antifouling film could be used for a long time. The high-performance plastic film produced in this example is shown in FIG.

First, 5 g of tetraethoxysilane was added to 10
0 ml of water-ethanol-propanol (volume ratio 3: 2
7:70) Dissolved in a mixed solution, stirred at 40 ° C. for about 5 hours, and allowed to stand at room temperature for 2 weeks to prepare a silica sol. Divide the resulting silica sol into four equal parts, leaving one
First, iron nitrate (III), aluminum nitrate or zirconium nitrate (IV) was added so as to be 5% by weight.
A seed sol was prepared by adding water so that the solid content concentration was 4% by weight, to prepare a coating liquid for forming a barrier layer.

Next, the same PET as in Examples 11 to 15 was used.
Film 9 (100 mm x 100 mm x 0.2 mm)
The obtained coating liquid for forming a barrier layer was spin-coated on the resultant, and the low-pressure mercury lamp (strength: 15 m
W / cm ² ) was irradiated for 5 minutes to cure. Thereby, the barrier layer was formed. Next, a photocatalyst film-forming coating liquid (using Ag as conductive fine particles) prepared in the same manner as in Examples 11 to 15 was spin-coated on the surface of the barrier layer, and the low-pressure mercury lamp (strength) was applied at 120 ° C. : 15 mW / cm ² ) for 5 minutes for curing.
As described above, the barrier layer 5 having a film thickness of 400 nm is formed on the substrate surface.
1 and an antistatic photocatalyst film 13 having a film thickness of 400 nm were laminated. The thin film obtained on the PET film had good film quality and strength.

Obtained high-performance plastic film 50
The performance of the antistatic photocatalytic film 13 in Examples 1-5
When evaluated in the same manner as above, the surface resistance was 10 ⁹ Ω / □ or less when any of the barrier layers was used, and the coloring by the tar of the cigarette and the adhesion of dust, which are the same as in Examples 11 to 15, were prevented. We were able to.

Further, the obtained high-performance plastic film 50 and, for comparison, the high-performance plastic film 30 produced in Example 11 (without barrier layer) was left for one year to remove the film from the substrate. The presence or absence was observed. The results are shown in Table 5. In Table 5, "x" indicates that peeling was observed in about 6 months, "△" indicates that peeling was observed in 1 year, and "○" indicates that peeling was not observed. Shows.

[0068]

[Table 5]

As can be seen from Table 5, in the film 30 of Example 11, peeling was observed in about half a year, whereas
In the films 50 produced in Examples 21 to 24, no peeling was observed at the half-year point. From this table, in Example 21 in which the barrier layer made of only silica was provided, peeling was observed after standing for about 1 year, whereas the barrier layer was made of a metal (Al, Fe) that deactivates the photocatalytic activity. Or Zr)
When added (Examples 22 to 24), peeling is not observed even if left for one year, and it is understood that it is preferable to add such a metal in order to maintain the adhesive strength.

Example 25 In this example, a film 50 having ATO dispersed in the barrier layer was produced. The method for producing the film 50 in this example is the same as that in Example 21 except that the coating liquid for forming the barrier layer is different.
The coating liquid for forming a barrier layer used in this example was prepared by adding 20 g of silica sol prepared in the same manner as in Example 11 to ATO as conductive fine particles prepared in the same manner as in Example 1.
Was prepared by adding 50 g of a conductive fine particle dispersion liquid containing the above and adding water so that the solid content concentration was 2% by weight.

The produced film 50 had excellent adhesiveness in which peeling of the film was not observed in about half a year as in Example 21, and further had an antifouling effect superior to that of Example 21.

[0072]

According to the present invention, it is difficult for foreign matter to adhere,
In addition, an article having an excellent antifouling effect can be obtained, which can efficiently decompose the attached organic matter by the photocatalyst. Furthermore, according to the present invention, it is possible to obtain an antifouling article that can be used for a long period of time even when an organic material is used as the substrate.

[Brief description of drawings]

FIG. 1 Conductive fine particle dispersion T formed on a glass substrate
FIG. 3 is a partial cross-sectional view schematically showing the structure of the iO ₂ film and its enlarged view.

FIG. 2 is a partial cross-sectional view showing the structure of a conductive layer-TiO ₂ layer laminated film formed on a glass substrate.

FIG. 3 is a partial cross-sectional view schematically showing a structure of a SiO ₂ film in which conductive fine particles and TiO ₂ fine particles are dispersed, which is formed on a PET film, and an enlarged view thereof.

FIG. 4 is a conductive layer-TiO formed on a PET film.
FIG. 3 is a partial cross-sectional view schematically showing the structure of a _2- dispersion SiO ₂ layer laminated film.

FIG. 5 is a partial cross-sectional view showing the structure of a high-performance plastic film including a photocatalyst film and a barrier layer.

[Explanation of symbols]

1 ... Glass substrate, 2 ... Conductive fine particles (dispersed phase), 3 ... T
iO ₂ (continuous phase), 4 ... Conductive photocatalyst film (conductive fine particle dispersed TiO ₂ film), 5 ... High-performance glass plate provided with conductive fine particle dispersed TiO ₂ film, 6 ... Conductive layer, 7 ... Photocatalyst (TiO 2).
₂ ) Layer, 8 ... Conductive photocatalyst film (conductive layer-photocatalyst layer laminated film), 9 ... PET film, 10 ... SiO ₂ (continuous phase), 11 ... Photocatalyst (TiO ₂ ) fine particles, 12 ... Conductive fine particles, 13 ... conductive photocatalyst film (conductive fine particle photocatalyst fine particle dispersed SiO ₂ film), 15 ... conductive layer, 16 ... SiO ₂ ,
18 ... Photocatalyst fine particle dispersed SiO ₂ film (photocatalyst layer), 19
... conductive layer - photocatalyst layer laminate film, 20 ... conductive layer - comprising a photocatalyst layer laminated film highly functional glass plates, high-performance plastic film with 30 ... conductive fine photocatalyst particles dispersed SiO ₂ film, 40 ... conductive layer - photocatalyst layer High-performance plastic film including a laminated film, 50 ... High-performance plastic film including a photocatalyst film and a barrier layer, 51 ... Barrier layer.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI B01D 53/36 H (72) Inventor Tomoji Oishi 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory ( 72) Inventor Ken Takahashi 7-1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Tadanori Michimoto 1-2-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Kazunari Shibata 1-2, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (56) Reference JP 8-1010 (JP, A) JP 10-175270 ( JP, A) International Publication 97/010186 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 21/00-38/74 B01D 53/00-53/96

Claims (11)

(57) [Claims] 1. A photocatalyst and a binder which catalyze the decomposition of organic substances.
Look including the door, 5-9 weight photocatalyst is the weight of the binder
The surface resistance of the photocatalyst film, which is double, is dispersed in the photocatalyst.
By the 10 9 ohm / □ or less by using the conductive fine particles made of a conductor was, the decomposition of organic matter and the catalyst and antifouling method characterized by preventing adhesion of foreign matter. 2. A article comprising a photocatalytic film containing a catalyst for photocatalytic degradation of organic substances, by preventing the charging of the photocatalyst film, possess antistatic mechanism for preventing adhesion of foreign matter, the antistatic mechanism , Dispersed in the photocatalyst film,
An antifouling article, which is a conductive fine particle composed of a body, wherein the photocatalytic film has a film thickness of 100 to 500 nm . 3. A article comprising a photocatalytic film containing a catalyst for photocatalytic degradation of organic substances, by preventing the charging of the photocatalyst film, possess antistatic mechanism for preventing adhesion of foreign matter, the antistatic mechanism , Dispersed in the photocatalyst film,
The photocatalyst fine particles are conductive fine particles having a crystallite diameter of 5 determined by X-ray.
An antifouling article having a thickness of 20 nm . 4. A article comprising a photocatalytic film containing a catalyst for photocatalytic degradation of organic substances, by preventing the charging of the photocatalyst film, possess antistatic mechanism for preventing adhesion of foreign matter, the antistatic mechanism , Dispersed in the photocatalyst film,
A conductive fine particle made of the body, the weight of the photocatalyst is a 5-9 times the weight of the binder
An antifouling article characterized by being present. Wherein the antistatic mechanism, the photocatalyst film or the serial <br/> mounting proof of claims 2 to 4, characterized in that the surface resistance value is a mechanism to 10 9 ohm / □ or less of Dirty articles. 6. A sheet-shaped substrate containing an organic polymer compound, a barrier layer made of an inorganic substance, and a catalyst for decomposing the organic substance.
A photocatalyst film containing a photocatalyst that is laminated in this order
A beam, by preventing charging of the photocatalyst film, possess antistatic mechanism for preventing adhesion of foreign matter, the antistatic mechanism, dispersed in the photocatalyst film, guide
Conductive fine particles composed of a body, the surface of the photocatalytic film
An antifouling article, which has a mechanism of reducing the resistance value to 109 Ω / □ or less . 7. The antifouling article according to claim 6 , wherein the barrier layer is a film of a metal oxide containing at least one element of Fe, Al and Zr. 8. The antifouling article according to claim 6 , further comprising a layer containing an adhesive on the surface on the side where the photocatalyst film is not formed, of the front and back surfaces of the base material. 9. The conductor is Sn, In, Ag, Pd, Cu, ATO (Sb-added Sn).
O2) and at least one of ITO (Sn-added In2O3) are contained, and the element according to any one of claims 2 to 4.
The antifouling article as described in the slip . 10. The photocatalyst is TiO2 or SrTiO3.
3. BaTiO3, WO3, and at least one of SiC , any one of claims 2 to 4, characterized in that
An antifouling article as described in Crab . 11. The antifouling article according to claim 3 or 4 , wherein the binder is SiO2.