JP2911021B2 - Photocatalyst for sticking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst which performs sterilization, deodorization and antifouling by utilizing a photocatalytic effect, and more particularly to a photocatalyst which can be applied.

[0002]

2. Description of the Related Art Since titanium oxide and zinc oxide are semiconductors, their application as a photocatalyst having photocatalytic activity has been reported. The photocatalytic activity means that the oxide semiconductor fine particles are excited by absorbing light (generally, ultraviolet light) having energy equal to or larger than the band gap, and the generated electrons and holes are exchanged with a substance adsorbed on the particle surface. Is an activity of oxidizing or reducing the adsorbed substance to decompose it. In order for this photocatalytic activity to occur, the oxide particles must be in direct contact with a substance (molecule) to be oxidized and reduced, and further irradiated with ultraviolet light.

[0003] There have been reports of attempts to sterilize, deodorize, and contaminate antioxidants by utilizing a photocatalyst made of an oxide semiconductor for the purpose of decomposing bacteria floating in a gas or gas that emits an offensive odor. However, in this case, it is necessary to fix highly active oxide semiconductor fine particles on the substrate and irradiate the surface with light. As a method of fixing the semiconductor fine particles having photocatalytic activity to the substrate surface, a method of adding a semiconductor oxide fine particle to a paint to form a coating film can be considered, but the photocatalytic activity is lost because the oxide fine particle surface is covered with a resin. . For titanium oxide, a method for producing a film of semiconductor fine particles by a sol-gel method has been proposed. However, since the sol-gel method requires heating in the production process, the substrate on which the titanium oxide is to be formed is limited, and a usable place is restricted. Is also limited. Further, vacuum or reduced pressure is required to form a film by sputtering or vapor deposition. Therefore, semiconductor fine particles having photocatalytic activity cannot be fixed to the currently used wall or ceiling by the sol-gel method, sputtering, or vapor deposition.

[0004]

SUMMARY OF THE INVENTION Zinc oxide fine particles having photocatalytic activity are used for walls and ceilings of buildings currently used.
In order to use the photocatalytic effect by attaching it to equipment etc.,
As described above, a method of adding a zinc oxide fine particle to a paint to form a coating film is also conceivable, but as described above, the photocatalytic activity is lost because the surface of the zinc oxide fine particle is covered with a resin. . So oxidation with photocatalytic activity
A metal substrate layer having zinc fine particles fixed on its surface;
It has an adhesive layer present on the side and a release layer present on the back side
Prepare a photocatalyst for attachment, and use it for building walls and ceilings.
It is conceivable to use it by attaching it to an instrument or the like.

An object of the present invention is to provide a metal substrate having a zinc oxide fine particle layer having a large photocatalytic activity firmly fixed on its surface.
Body layer, adhesive layer inside it, and back side
It has a release layer, and has a structure that can be easily attached to walls, ceilings, appliances, etc. of buildings, that is, it can be simply and easily attached by simply peeling off the release layer (release paper). Provide a photocatalyst for sticking that has a structure and can be manufactured at low cost. By such a photocatalyst for sticking, it can be used for a wide range of buildings, including inner and outer walls, ceilings, deodorizers, air purifiers, sterilizers, etc. It is to enable sterilization, deodorization, and antifouling by photocatalytic activity in a use range.

[0006]

The present inventors have Means for Solving the Problems] As a result of various studies in order to achieve the above object, the zinc oxide fine particle layer, a gold
By having a structure having a base metal layer, an adhesive layer (or a layer made of a double-sided adhesive tape), and a release layer (release paper layer), the photocatalyst can be attached to places and surfaces where it was impossible to attach the photocatalyst until now. The present inventors have found that a possible photocatalyst can be produced and completed the present invention.

A first embodiment of the photocatalyst for application according to the present invention comprises:
It is characterized by having a zinc oxide fine particle layer present on the front surface, a metal substrate layer present inside the zinc oxide fine particle layer, an adhesive layer present inside the zinc oxide fine particle layer, and a release layer present on the rear surface. The photocatalyst for application in such an embodiment, for example, anodizing the surface of a metal zinc substrate or a substrate containing metal zinc as a main component to provide a zinc oxide coating composed of zinc oxide fine particles on the surface,
It is obtained by applying an adhesive to the other surface to provide an adhesive layer 4 or attaching a double-sided tape 2 and further providing a release layer 3 on the adhesive layer 4 or the double-sided tape 2.

[0008] In the present invention, "metal" means metal zinc ,
It also includes a zinc alloy or a metal whose surface is galvanized , and it is sufficient that a zinc oxide fine particle layer is obtained as a surface layer on the metal base layer by oxidizing the metal. Further, galvanized galvanized galvanized sheets are readily available and inexpensive. Further, in the present invention, "metal substrate"
For example, in the case of "a substrate made of metal zinc or a substrate containing metal zinc as a main component", a zinc plate, a zinc net, a zinc foil, a zinc wire, a zinc alloy plate containing zinc as a main component, and a net made of zinc alloy , Foil, wire, etc. The conditions for the anodic oxidation of the “substrate of metallic zinc or the substrate containing metallic zinc as a main component” as described above may be the conditions generally used for anodic oxidation of zinc. When the surface of zinc or the surface containing zinc is anodized, a part of zinc is eluted from the surface, and the eluted zinc becomes zinc oxide fine particles and precipitates on the surface to form a zinc oxide film. Zinc oxide obtained by anodic oxidation is generally fine particles having a particle size of 0.2 μm or less, particularly 0.1 μm or less, that is, has a particle diameter that allows efficient irradiation of ultraviolet rays, and has a large specific surface area. Furthermore, since it has a structure in which molecules and bacteria to be decomposed can enter and exit, a large amount of gas to be treated is adsorbed.

The photocatalyst for application according to the present invention may be in the form of a plate, foil, or tape, but may be formed into any shape depending on the shape of the surface to be bonded. In addition, the "adhesive layer" may be a variety of adhesives, or one surface of a double-sided adhesive tape may be attached to the back surface of the anodized plate, and the other surface of the tape may be used as the adhesive surface. The photocatalyst for sticking obtained by these production methods can be used for a suitable use according to the flexibility, rigidity and the like depending on the thickness of the metal substrate. In particular, when the thickness of the metal substrate is set to 1 mm or less, it becomes possible to perform processing such as cutting and bending so that it can be attached to a surface other than a flat surface unlike a sintered plate such as a tile, and also restricts the weight. be able to.

A second embodiment of the photocatalyst for sticking of the present invention is as follows.
It has a zinc oxide fine particle layer present on the surface, a metal layer present on the inside thereof, a base layer present on the inside thereof, an adhesive layer present on the inside thereof, and a release layer present on the back surface. I do. The photocatalyst for sticking in such an embodiment,
For example, as shown in FIG. 3, a metal layer 7, for example, a metal zinc layer or a layer containing metal zinc as a main component is provided on the surface of the substrate 6, and the surface of the layer is anodized to oxidize the surface. A coating of zinc oxide composed of zinc fine particles (oxide semiconductor fine particle layer 1) is provided, and an adhesive is applied to the other surface of the base to provide an adhesive layer 4, or a double-sided tape 2 is attached, and the adhesive layer 4 or a double-sided tape 2 to obtain a release layer 3.

In the above embodiment, the term "metal layer" refers to a metal zinc coating layer formed on the surface of a substrate of various shapes such as metal, insulator, carbon fiber, etc. by plating, vapor deposition, thermal spraying, sputtering, or the like. It is. That is , resin, glass,
It is possible to use an insulator such as a cloth or a film, and physically and chemically apply a metal zinc coating thereon and fix it.
Examples of the method of physically and chemically applying a metal zinc coating or a coating containing zinc as a main component include a vapor deposition method, a sputtering method, a thermal spraying method, and an electroless plating method. For example, a zinc metal layer may be provided by spraying zinc, and this may be anodized.

The photocatalyst for application obtained by these production methods can be used for a suitable application depending on the properties of the substrate such as flexibility, flexibility, rigidity and strength.

[0013]

EXAMPLE 1 Zinc foil (10 cm × 10 cm, thickness 0.1 cm) degreased and washed
mm, the back side is covered with vinyl tape) in an electrolytic solution (20 g of sodium hydroxide, 10 g of sodium nitrate, 1 liter of water), and this is used as an anode. A stainless steel plate (10 cm × 10 cm) is used as a cathode. The distance between them was 10 cm, and a direct current voltage of 10 V was applied for 10 minutes to perform anodization. Thereafter, this was washed and dried to obtain a zinc oxide coated foil. Fine particles (average particle size less than 50 nm) in the zinc oxide film-coated foil by X-ray diffraction and transmission electron microscope observation.
It was confirmed that zinc oxide was precipitated. The thickness of the coating was about 3 μm.

After the vinyl tape on the back surface of the zinc oxide coated foil was peeled off, a double-sided adhesive tape with a release paper was attached to this surface. Therefore, this photocatalyst comprises an oxide semiconductor fine particle layer, a metal substrate layer, a double-sided tape layer (adhesive layer), and a release layer. Since this photocatalyst was composed of a thin foil, it could be bent, and the oxide film did not peel off even when the radius was 1 cm.

Example 2 A sheet (10 cm × 10 c
m, a thickness of 0.3 mm, and a back surface covered with a vinyl tape), put this in an electrolytic solution (8 g of sodium hydroxide, 17 g of sodium carbonate, and 1 liter of water), use this as an anode, and use a stainless steel plate ( 10cm × 10cm)
, The distance between the electrodes is 10 cm, and the DC voltage is 2
OV was applied for 20 minutes to perform anodization. Thereafter, this was washed and dried to obtain a plate with a zinc oxide coating. After the vinyl tape on the back surface of the zinc oxide coated plate was peeled off, an acrylic adhesive was applied to this surface to form an adhesive layer, and after drying, a peeling film with a silicone film was adhered. After peeling off the release film, this plate could be easily and firmly adhered to a flat surface.

Example 3 Metallic zinc powder (average particle size: 65 μm) was sprayed with argon on a cotton cloth (10 cm × 10 cm) to form a metallic zinc coating on the surface. The thickness of the coating was about 0.5 mm. No damage such as burning was found on the cotton fabric by this thermal spraying.
Using the metal-zinc coated cotton cloth, the electrolytic solution used in Example 1, and the stainless steel cathode plate, the distance between the two electrodes was set to 10c.
m and anodized by applying a DC voltage of 10 V for 5 minutes. An acrylic pressure-sensitive adhesive was applied to the back surface of the cotton cloth with the zinc oxide film, and then dried, and a release film with a silicone film was bonded. After peeling off the release film, this plate could be easily and firmly adhered to a flat surface.

Example 4 The photocatalytic activity was measured using the zinc oxide coated foil prepared in Example 1. The measurement of the photocatalytic ability is performed by attaching a zinc oxide coated foil (10 cm × 10 cm, 6 sheets) to the inner side surface of a cylindrical glass container (volume of 10 liters), covering with a flat glass, and making the inside of the glass container a sealed system. The gas to be decomposed is enclosed here. Then, ultraviolet rays (black light 10 W × 5 lamps) were irradiated from the upper outside of the glass, and the decomposition amount of the gas to be treated was measured by a gas chromatograph. Here, acetaldehyde was used as the gas to be treated, which is generally used as an index for decomposing bacteria and organic substances. Therefore, the results obtained here correspond to the sterilizing ability and the deodorizing ability. 50p acetaldehyde gas in container
When irradiation with ultraviolet light was started after the injection, the concentration was reduced to 1 ppm after 20 minutes, and it was confirmed that the solution was decomposed by the photocatalyst.

[0018]

The photocatalyst according to the present invention is characterized in that zinc oxide fine particles
The child layer is fixed to the metal base layer, and further has an adhesive surface that can be pasted, by peeling off the peeling layer and pasting it, the inner and outer walls of the already built building, ceiling, and other devices after production, It can be easily attached to a surface that requires a photocatalytic function without processing, and a sterilizing and deodorizing function can be added. Further, it can be easily attached to the inside and outside of a building where the film formation has been difficult so far, such as a deodorizer, an air purifier, and a sterilizer. In particular, by setting the thickness of the metal plate to 1 mm or less, processing such as cutting and bending can be freely performed even on a surface other than a flat surface unlike a sintered plate such as a tile. Further, the anodized metal plate according to the present invention can be peeled off when the photocatalytic activity is deteriorated due to contamination or the like due to long-term use, and has an advantage that it can be replaced with a new one.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a photocatalyst in which a zinc oxide fine particle layer is provided on a double-sided adhesive tape .

FIG. 2 is a cross-sectional view of a photocatalyst obtained in Example 1 of the present invention.

FIG. 3 is a cross-sectional view of a photocatalyst obtained in Example 3 of the present invention.

FIG. 4 is a cross-sectional view of a photocatalyst according to another embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 zinc oxide fine particle layer 2 double-sided adhesive tape layer 3 release layer 4 adhesive layer 5 metal base layer 6 base layer 7 metal layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Fujishima 710-5 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Kazuhito Hashimoto 2000 Minami-Kosugaya-House 2 at 506, Kosugaya-cho, Sakae-ku, Yokohama, Kanagawa 2 References JP-A-5-253544 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01J 35/02 B01J 23/06 B01J 21/06

Claims (4)

(57) [Claims] 1. A bonding method comprising: a zinc oxide fine particle layer present on the front surface; a metal substrate layer present inside the zinc oxide fine particle layer; an adhesive layer present inside the zinc oxide fine particle layer; and a release layer present on the rear surface. Photocatalyst. 2. A zinc oxide fine particle layer existing on the front surface, a metal layer existing inside the fine particle layer, a base layer existing inside the zinc oxide fine particle layer, an adhesive layer existing inside the zinc oxide fine particle layer, and a release layer existing on the back surface. A photocatalyst for sticking, comprising: 3. The thickness of the metal base layer is 1 mm or less.
The photocatalyst according to claim 1, which is: 4. The photocatalyst according to claim 2, wherein the thickness of the metal layer is 1 mm or less.