JP2002239396A - Photocatalyst carrying structure and method for producing the same - Google Patents

Abstract

(57) [Problem] To provide a photocatalyst-carrying structure capable of achieving a high antifouling function without causing interference colors. SOLUTION: In a photocatalyst supporting structure having a photocatalyst film adhered to one surface of a substrate, the photocatalyst film has a thickness of 5 μm.
0 nm or less, and the surface roughness (Ra) of the surface of the substrate on which the photocatalytic film is to be deposited is set to 1 of the film thickness of the photocatalytic film.
/ 2 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photocatalyst-carrying substance. More specifically, the present invention relates to a photocatalyst-supporting structure having an excellent antifouling function and antifogging function.

[0002]

2. Description of the Related Art Photocatalytic substances have been attracting attention as substances capable of decomposing various pollutants since environmental issues have been widely taken up. Photocatalytic substances have many effects such as decomposition of various organic substances, antifouling, antifogging and sterilization, and some of them have been put into practical use.

[0003] Of these, focusing on the antifouling and antifogging effects, there are products that apply a photocatalytic substance to a window glass or an outer wall and claim an antifouling effect, and products that are adhered to a mirror and exhibit an antifogging effect. Are sold.

Most of these products are obtained by applying photocatalyst fine particles to a substrate. The application of such fine particles is inexpensive and easy, but has problems such as low photocatalytic performance and low durability.

As one of the methods for solving these problems, there is a method of forming a film by a vapor deposition method in which a vapor of a photocatalytic substance is adhered to a substrate in a vacuum. There are many vapor deposition methods, such as a vacuum deposition method, an ion plating method, a sputtering method, a CVD method, and an ion implantation method. When the film is formed by these methods, the film is firmly adhered to the substrate without a binder, and excellent photocatalytic properties can be obtained by appropriately adjusting the film forming conditions.

However, in a film uniformly formed on a substrate, the reflected light from the film surface and the reflected light from the interface of the substrate interfere with each other to produce an interference color. As a result, another new problem has been pointed out that the pattern on the decorated wall becomes difficult to see, and the transparency of transparent glass or the like is reduced.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photocatalyst supporting structure which can solve the above-mentioned drawbacks of the prior art and does not cause interference colors and can achieve a high antifouling function. It is.

[0008]

The above object is achieved by forming a photocatalytic film having a thickness of 50 nm or less on a substrate.

As a result of intensive studies, the present inventors have found that a photocatalyst structure having excellent antifouling function without interference color can be obtained if the thickness of the photocatalyst film is 50 nm or less. The inventor has also discovered that the surface roughness of the substrate on which the photocatalytic film is formed is preferably equal to or less than half the thickness of the photocatalytic film formed.

In order to prevent interference colors, the thickness of the photocatalyst film may be reduced so that light interference does not occur. However, when a thin film is formed on a substrate having a rough surface, the film becomes discontinuous and the surface of the substrate is exposed, so that the antifouling function is deteriorated. Even if the film is formed on a substrate having a good surface property, if the film thickness is too small, an island-like structure is formed, which also results in a discontinuous film. By subjecting a substrate having good surface properties to plasma treatment, a thin and uniform photocatalytic film can be formed, and the occurrence of interference colors can be prevented without reducing the antifouling function. .

[0011]

FIG. 1 is a schematic sectional view of an example of a photocatalyst supporting structure according to the present invention. In FIG.
Denotes a photocatalyst supporting structure according to the present invention, reference numeral 3 denotes a substrate, and reference numeral 5 denotes a photocatalyst film.

In the photocatalyst supporting structure 1 of the present invention, the thickness of the photocatalyst film 5 is in the range of 2 nm to 50 nm. As described above, when the thickness of the photocatalyst film 5 exceeds 50 nm,
Interference color occurs. Therefore, the thickness of the photocatalyst film 5 is 50 n
m or less. On the other hand, when the thickness of the photocatalyst film 5 is less than 2 nm, the photocatalyst film becomes an island shape, and a photocatalyst film having a uniform thickness may not be obtained.

The surface roughness of the substrate 3 affects the quality of the photocatalyst film 5 formed on the substrate. In order to obtain a photocatalyst film 5 having no interference color and having an excellent antifouling function, the surface roughness of the substrate is preferably not more than の of the thickness of the photocatalyst film to be formed. When the surface roughness of the substrate is more than 1/2 of the thickness of the photocatalyst film to be formed, the film becomes discontinuous and the surface of the substrate is exposed, so that the antifouling function may be deteriorated. Although the lower limit of the substrate surface roughness is not particularly limited, generally, the lower limit is 表面 of the photocatalytic film to be formed.
It may be 0 or more. If the surface roughness of the substrate is smaller than this value, not only the desired effect is saturated, but also the surface treatment cost of the substrate increases, which is uneconomical.

Even if a very smooth substrate is used, if the thickness of the photocatalyst film is reduced, an island-like structure is formed, so that the surface of the substrate is exposed and the antifouling function is deteriorated. In order to prevent this, it is effective to subject the substrate surface to plasma treatment before film formation. Since the substrate surface is cleaned and active points are uniformly distributed, a continuous film can be formed even when the film thickness is small.

The material of the substrate 3 in the photocatalyst supporting structure 1 of the present invention is not particularly limited. Any material such as plastics, glass, ceramics, metal, cloth or paper can be used as the substrate 3. The thickness of the substrate 3 is not particularly limited. Substrates of known and conventional thickness can be used. An adhesive or an adhesive can be applied to the back surface of the substrate (that is, the surface on which the photocatalyst film is not deposited) so that the photocatalyst supporting structure can be easily attached to another support (not shown). .

The material of the photocatalyst film 5 is Cd, Zn,
In, Pb, Mo, W, Sb, Bi, Cu, Hg, T
i, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga,
Oxides of Si and Cr, perovskites such as SrTiO ₃ and CaTiO ₃ , or CdS, ZnS, In ₂
S ₃ , PbS, Mo ₂ S, WS ₂ , Sb ₂ S ₃ , Bi ₂
S ₃ , ZnCdS ₂ , sulfide of Cu ₂ S, CdSe, I
n ₂ Se ₃ , WSe ₂ , HgSe, PbSe, CdTe
Metal chalcogenides, other GaAs, Si, Se,
Cd ₂ P ₃ , Zn ₂ P ₃ , InP, AgBr, Pb
I ₂ , HgI ₂ and BiI ₃ are preferred. Alternatively, a composite containing at least one selected from the above semiconductors, for example, CdS / TiO ₂ , CdS / AgI, Ag ₂ S /
AgI, CdS / ZnO, CdS / HgS, CdS / P
bS, ZnO / ZnS, ZnO / ZnSe, CdS / H
_{gS, CdS x / CdSe 1-} x, CdS x / Te
_{1-x, CdSe x / Te} 1-x, ZnS / CdSe,
ZnSe / CdSe, CdS / ZnS, TiO 2 / Cd
_{3 P 2, CdS / CdSeCd y} Zn 1-y S, CdS
/ HgS / CdS is preferably used. TiO ₂ is particularly preferred.

As a method for forming the photocatalyst film 5, any method can be used as long as a thin film is formed in a vacuum.
For example, it can be formed by any film forming method such as a vacuum evaporation method, an ion plating method, a plasma CVD method, and a sputtering method. Such a film forming method is well known to those skilled in the art.

FIG. 2 is a schematic sectional view of another embodiment of the photocatalyst supporting structure according to the present invention. In FIG. 1, reference numeral 1 denotes a photocatalyst supporting structure according to the present invention, reference numeral 3 denotes a plastic substrate, reference numeral 5 denotes a photocatalytic film, and reference numeral 7 denotes an intermediate layer.

In the photocatalyst supporting structure 1 shown in FIG. 1, when the substrate 3 is made of plastics, the photocatalyst film 5 on the surface is formed.
The plastic may be decomposed by the photocatalytic action of. In order to avoid this danger, in the photocatalyst supporting structure 1 shown in FIG. 2, an intermediate layer 7 is interposed between the plastic substrate 3 and the photocatalyst film 5. As the intermediate layer 7 for preventing direct contact between the substrate and the photocatalytic film, any substance having no or weak photocatalytic action can be used without any problem. Even if another functional layer (not shown) such as an ultraviolet cut layer, an infrared cut layer, an electromagnetic wave cut layer, etc. is laminated in addition to the intermediate layer 7 for preventing direct contact between the substrate 3 and the photocatalytic film 5 no problem. The intermediate layer 7 itself may be a layer having another functionality such as an ultraviolet cut layer, an infrared cut layer, and an electromagnetic wave cut layer. In the photocatalyst supporting structure 1 shown in FIG. 1, when the substrate 3 is made of a material other than plastic, the use of the intermediate layer 7 is not particularly necessary, but may be used.

The method for forming the intermediate layer 7 is not particularly limited.
It can be conveniently formed by the same evaporation method as the photocatalyst film. The material for forming the intermediate layer 7 is, for example, SiO _x , IT
Examples thereof include oxides such as O, SnO, and ZnO, and metals such as Ag. The intermediate layer 7 may be a single layer, or may have a structure in which a plurality of layers are stacked. The thickness of the intermediate layer 7 is generally in the range of 2 nm to 70 nm. When the thickness of the intermediate layer 7 is less than 2 nm, the effect of blocking the photocatalytic action becomes insufficient, and the decomposition of the lower plastic substrate cannot be prevented. On the other hand, when the thickness of the intermediate layer 7 is more than 70 nm, not only the effect of blocking the photocatalytic action is saturated, but also the generation of interference colors by the intermediate layer.

FIGS. 3 and 4 are schematic structural views of an example of an apparatus for producing the photocatalyst-carrying structure of the present invention. Hereinafter, the method for forming the photocatalyst film 5 of the present invention will be described with reference to the drawings. FIG.
When a film is formed by a sputtering apparatus, first, a high-frequency power source 10 is applied to a substrate 3 supported by a rotatable substrate holder 9.
To apply a bias voltage to perform plasma processing on the substrate surface. Reference numeral 11 indicates a matching box. At this time, no voltage is applied to the target 12 so that no film is formed on the substrate 3. Oxygen, nitrogen, argon, helium, hydrogen, a mixed gas thereof, or the like is used as the plasma processing gas introduced from the gas introduction pipe 14, and oxygen gas has the highest effect of preventing the island structure. Next, when the intermediate layer is not provided, the photocatalytic film is formed on the surface of the substrate 3 by applying a voltage from the high frequency power supply 18 to the target 12 as it is.

When the intermediate layer 7 is provided, the target 12
Then, the intermediate layer 7 is formed using an intermediate layer forming material, the substrate is moved to the adjacent film forming chamber, and a voltage is applied to the target 13 by the high frequency power supply 16 to form a photocatalytic film. When a layer other than the intermediate layer is provided, the film is sequentially formed by appropriately changing the material of the targets 12 and 13. In the present invention, the intermediate layer has a function of separating the substrate and the titanium oxide to prevent the decomposition of the substrate by the photocatalyst. Layers other than the intermediate layer can also be used. Such a layer is a layer that provides a function other than separation of the substrate and the titanium oxide, and is, for example, an infrared cut layer, an ultraviolet cut layer, an electromagnetic wave cut layer, or an antireflection layer.

When the film is formed by the ion plating apparatus shown in FIG. 4, the film is formed on the substrate 3 which is wound on the winding roll 25 from the supply roll 22 via the cooling drum 24. First, plasma processing of the substrate surface is performed in the plasma pre-processing chamber 26. When no intermediate layer is provided, the evaporation source 33 is heated by an electron beam emitted from an electron gun 34.
Is heated and dissolved to form a photocatalytic film as it is. When the intermediate layer is provided, the evaporation source 33 is heated and melted by electron beam heating to form the intermediate layer, and then the raw material of the evaporation source 33 is changed to a photocatalytic material, and the photocatalytic film is formed while the film is reversed. . When a layer other than the intermediate layer is provided, the film is sequentially formed by changing the material of the evaporation source 33 as appropriate. At the time of vapor deposition, a high-frequency voltage is applied to the cooling drum 24 by a high-frequency power supply 28 to generate plasma and control the film quality. Others
In FIG. 4, reference numeral 20 denotes a shutter, 23 denotes a guide roll, 27 denotes a voltage application roll, 28 and 31 denote high frequency power supplies, 29 and 32 denote matching boxes, and 30 denotes a high frequency electrode.

[0024]

The present invention will now be specifically illustrated by way of examples.

Example 1 Using a sputtering apparatus shown in FIG.
After pretreating a PET film having a m and Ra (surface roughness) of 3 nm with oxygen plasma, a SiO _x film having a thickness of 30 nm and a photocatalytic TiO ₂ film having a thickness of 8 nm were sequentially formed. Table 1 below shows the plasma pretreatment conditions and the film forming conditions.

[0026]

[Table 1] Table 1 Plasma pretreatment conditions and sputter deposition conditions

Example 2 Using a sputtering apparatus shown in FIG.
After pre-treating the Al substrate with Ra of 10 nm with oxygen plasma, a photocatalytic TiO ₂ film with a thickness of 30 nm was formed. Other film forming conditions were the same as in Example 1.

Example 3 Using a sputtering apparatus shown in FIG.
After pre-treating the Al substrate with Ra of 10 nm with oxygen plasma, a photocatalytic TiO ₂ film with a thickness of 40 nm was formed. Other film forming conditions were the same as in Example 1.

Example 4 Using a sputtering apparatus shown in FIG.
After pre-treating the Al substrate having a thickness of 15 nm with oxygen plasma, a photocatalytic TiO ₂ film having a thickness of 30 nm was formed. Other film forming conditions were the same as in Example 1.

Example 5 Using an ion plating apparatus shown in FIG.
After pretreating a PEN film having a thickness of 0 μm and Ra of 15 nm with oxygen plasma, a SiO _x film having a thickness of 60 nm and a thickness of 30 nm were obtained.
A photocatalytic TiO ₂ film having a thickness of nm was formed. Table 2 shows the film forming conditions.

[0031]

[Table 2] Table 2 Plasma pretreatment conditions and ion plating film formation conditions

Example 6 Using a sputtering apparatus shown in FIG.
After pre-treating a PET film having a thickness of 5 nm and Ra of 5 nm with oxygen plasma, a SiO _x film having a thickness of 18 nm and an A film having a thickness of 8 nm are formed.
A g film, an SiOx film having a thickness of 18 nm, and a photocatalytic TiO ₂ film having a thickness of 18 nm were formed. Table 3 below shows the conditions for forming the Ag film. Other conditions were the same as in Example 1 to form a film.

Example 7 Using a sputtering apparatus shown in FIG.
After pretreatment of an Al substrate with a Ra of 10 nm with oxygen plasma, a photocatalytic ZnO film with a thickness of 50 nm was formed under the conditions shown in Table 3. Other conditions were the same as in Example 1.

[0034]

Table 3 Ag film sputtering conditions Flow rate Pressure RF output RF frequency introduction gas (sccm) (Torr) Target (W) (MHz) O ₂ / Ar 20/20 0.002 ZnO 1.0 13.56 Ar 50 0.003 Ag 1.0 13.56

Comparative Example 1 Using a sputtering apparatus shown in FIG.
After pre-treating the Al substrate with Ra of 10 nm with oxygen plasma, a TiO ₂ film with a thickness of 60 nm was formed. Other film forming conditions were the same as in Example 1.

Comparative Example 2 Using the ion plating apparatus shown in FIG.
After pretreating a PET film having a thickness of 0 μm and Ra of 10 nm with oxygen plasma, a SiO _x film having a thickness of 80 nm and a thickness of 30 nm were obtained.
nm of TiO ₂ film was formed. Other film forming conditions were the same as in Example 5.

Comparative Example 3 Using the ion plating apparatus shown in FIG.
After pretreating a PET film having a thickness of 0 μm and Ra of 30 nm with oxygen plasma, a SiO _x film having a thickness of 50 nm and a thickness of 30 nm were obtained.
nm of TiO ₂ film was formed. Other film forming conditions were the same as in Example 5.

Comparative Example 4 Using a sputtering apparatus shown in FIG.
After pre-treating the Al substrate of Ra 25 nm with oxygen plasma, a TiO ₂ film having a thickness of 30 nm was formed. Other film forming conditions were the same as in Example 1.

Comparative Example 5 Using a sputtering apparatus shown in FIG. 3, an Al plasma having a thickness of 1 mm and a Ra of 10 nm was not subjected to oxygen plasma treatment.
A TiO ₂ film having a thickness of 30 nm was formed on the substrate. Other film forming conditions were the same as in Example 1.

The interference colors of the samples obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were visually observed. The contact angle of each sample was measured with a contact angle meter. The results are summarized in Table 4 below.

[0041]

Table 4 specimen interference color contact angle (deg) Example 1 Colorless 8.9 Example 2 Colorless 7.2 Example 3 very thin brown 6.5 Example 4 Colorless 7.3 Example 5 Colorless 6 9.9 Example 6 Very light brown 7.1 Example 7 Colorless 9.9 Comparative Example 1 Light brown 6.3 Comparative Example 2 Light brown 7.6 Comparative Example 3 Colorless 13.8 Comparative Example 4 Colorless 15.3 Comparative Example 5 colorless 17.2

Each of the samples of Examples 1 to 7 was so thin that interference colors did not appear or was hardly noticeable, and the contact angles were all 10
° and smaller. In contrast, Comparative Example 1 had a thick TiO ₂ film, and Comparative Example 2 had a brown interference color due to a thick SiO _x film. In Comparative Examples 3 and 4, the surface of the substrate was rough, and in Comparative Example 5, an island-like structure was formed without performing the plasma pretreatment. It became big as above.

The sample of Example 5 had a wavelength of 200 nm to 380 because the PEN film had an ultraviolet ray cut function.
The ultraviolet light of nm was cut by 80% or more. The sample of Example 6 has a wavelength of 780 n since the Ag film has an infrared cut function.
More than 60% of infrared rays of m to 1500 nm were cut.

[0044]

As described above, according to the present invention,
A photocatalyst-carrying structure that does not generate interference colors and can achieve a high antifouling function can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of a photocatalyst supporting structure according to the present invention.

FIG. 2 is a schematic sectional view of another embodiment of the photocatalyst supporting structure according to the present invention.

FIG. 3 is a schematic sectional view of an example of a sputtering apparatus used for manufacturing a photocatalyst supporting structure according to the present invention.

FIG. 4 is a schematic sectional view of an example of an ion plating apparatus used for manufacturing a photocatalyst supporting structure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photocatalyst holding structure of this invention 3 Substrate 5 Photocatalytic film 7 Intermediate layer 9 Substrate holder 10, 16, 18 High frequency power supply 11 Matching box 12, 13 Target 14 Gas outlet 20 Shutter 22 Supply roll 23 Guide roll 24 Cooling drum 25 rolls Take-off roll 26 Plasma pretreatment chamber 27 Voltage applying roll 28, 31 High-frequency power supply 29, 32 Matching box 30 High-frequency electrode 33 Evaporation source 34 Electron gun

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 37/02 301 B01J 37/02 301P 37/34 37/34 C23C 14/08 C23C 14/08 E 14 / 24 14/24 NF term (reference) 4G069 AA03 AA08 BA02B BA04B BA48A BB04B BC32B BC35B CD10 DA05 EB05 EB15X EB15Y EC30 ED02 ED04 EE06 FA03 FB02 FB58 4K029 AA02 AA11 BA04 BA46 BA48 BB02 CA01

Claims (9)

[Claims] 1. A photocatalyst supporting structure in which a photocatalyst film is applied to one surface of a substrate, wherein the photocatalyst film has a thickness of 50 nm or less; A photocatalyst-carrying structure, wherein the surface roughness (Ra) is equal to or less than half the thickness of the photocatalyst film. 2. The photocatalytic film has a thickness of 2 nm to 50 nm.
The photocatalyst supporting structure according to claim 1, wherein the surface roughness of the substrate is within a range of 1/20 to 1/2 of the thickness of the photocatalytic film. 3. The method according to claim 1, wherein the substrate is made of a material selected from the group consisting of plastics, and an intermediate layer is further provided between the substrate and the photocatalytic film. Item 4. The photocatalyst-supporting structure according to Item 1. 4. The method according to claim 3, wherein the thickness of the intermediate layer is in a range of 2 nm to 70 nm, and the intermediate layer is composed of a single layer or a plurality of layers. Photocatalyst carrying structure. 5. The photocatalyst supporting structure according to claim 3, wherein the intermediate layer has a function of blocking at least one kind of radiation selected from the group consisting of infrared rays, ultraviolet rays, and electromagnetic waves. . 6. The photocatalyst supporting structure according to claim 1, wherein a pressure-sensitive adhesive or an adhesive layer is applied to the other surface of the substrate. 7. A method for manufacturing a photocatalyst supporting structure, comprising: depositing a photocatalyst film on one surface of a substrate, wherein the photocatalyst film is deposited after plasma treatment of the substrate surface. The method of manufacturing the structure. 8. After the substrate surface is plasma-treated,
The method for manufacturing a photocatalyst supporting structure according to claim 7, wherein an intermediate layer is first deposited, and then the photocatalyst film is deposited. 9. The method according to claim 7, wherein the plasma processing is performed in an oxygen gas atmosphere.