Photocatalyst-coated resin member

Abstract

To provide a photocatalyst-coated resin member capable of exhibiting self-cleaning properties over a long period of time.SOLUTION: The photocatalyst coated resin member has a photocatalyst coating film on the surface of a resin base material. Since the photocatalyst coated film has a photocatalyst layer and a shielding layer in order from the surface side, the photocatalyst layer is a layer in which anatase-type titanium oxide particles are dispersed in a glass binder, and the shielding layer is a layer for preventing contact between the anatase-type titanium oxide particles and the resin substrate and is formed of an inorganic substance comprising at least one selected from the group consisting of metals, alloys and ceramics, a photocatalyst-coated resin member capable of exhibiting a self-cleaning property over a long period of time can be provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a photocatalyst-coated resin member, and more particularly to a resin member having self-cleaning properties. [Background technology]

[0002] Titanium oxide has a photocatalytic effect that causes oxidation when exposed to light energy, and can oxidize and decompose organic matter such as pollutants and odorous substances. It also exhibits antibacterial and antiviral effects, so by coating the surface of a component with titanium oxide, it can impart self-cleaning properties that keep the surface clean.

[0003] Patent Document 1 describes a photocatalytic coating material that suppresses the transition of titanium oxide from anatase to rutile and improves the adhesion of titanium oxide particles by providing a photocatalytic film formed by thermally spraying large-diameter anatase titanium oxide particles onto a binder layer of softened thermoplastic resin on the surface of an FRP substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-238115 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the photocatalytic coating material described in Patent Document 1, the thermoplastic resin in the binder layer comes into contact with the titanium oxide particles, which causes oxidative decomposition of not only the contaminants but also the thermoplastic resin, resulting in peeling of the photocatalytic film or detachment of the titanium oxide particles from the photocatalytic film, thereby inactivating the photocatalytic effect.

[0006] The present invention has been made in consideration of the problems associated with the prior art, and its object is to provide a photocatalyst-coated resin member that can exhibit self-cleaning properties over a long period of time. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by providing a shielding layer between a photocatalyst layer in which anatase type titanium oxide particles are dispersed in a glass binder and a resin substrate, thereby preventing contact between the anatase type titanium oxide particles and the resin substrate, and have thus completed the present invention.

[0008] That is, the photocatalyst-coated resin member of the present invention comprises a photocatalyst coating on the surface of a resin substrate. The photocatalytic coating has, in order from the surface side, a photocatalytic layer and a shielding layer, the photocatalyst layer is a layer in which anatase-type titanium oxide particles are dispersed in a glass binder, The shielding layer is a layer that prevents contact between the anatase type titanium oxide particles and the resin substrate, and is characterized in that it is formed of an inorganic material consisting of at least one material selected from the group consisting of metals, alloys, and ceramics. [Effects of the Invention]

[0009] According to the present invention, contact between the anatase type titanium oxide particles and the resin substrate is prevented, and therefore it is possible to provide a photocatalyst-coated resin member that can exhibit self-cleaning properties for a long period of time. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view showing the layer structure of a photocatalyst-coated resin member. DETAILED DESCRIPTION OF THE INVENTION

[0011] The photocatalyst-coated resin member of the present invention will now be described in detail. The photocatalyst-coated resin member of the present invention comprises a resin substrate and a photocatalytic coating, the photocatalytic coating being formed on the surface of the resin substrate.

[0012] The photocatalytic coating has a photocatalytic layer on the surface and a shielding layer on the resin substrate side. The photocatalytic layer is a layer in which anatase type titanium oxide particles are dispersed in a glass binder, and the shielding layer is a layer that prevents contact between the anatase type titanium oxide particles and the resin substrate.

[0013] When light hits the anatase type titanium oxide particles in the photocatalyst layer of the photocatalyst-coated resin component, electrons are generated in the conduction band and holes are generated in the valence band. This decomposes water and oxygen in the air to produce active oxygen (·OH, O2 - ) and hydrophilic groups (-OH), and this photocatalytic reaction oxidizes and decomposes organic substances such as pollutants while also making the surface hydrophilic.

[0014] In the photocatalyst layer of the present invention, the binder is glass, so that the binder is not decomposed by the photocatalytic reaction, and deterioration of the photocatalyst layer itself and detachment of anatase titanium oxide particles from the photocatalyst layer can be prevented.

[0015] Furthermore, since the photocatalyst layer of the present invention is transparent and uses glass as the binder as described above, light is incident not only on the anatase type titanium oxide particles on the surface of the photocatalyst layer but also on the anatase type titanium oxide particles inside the photocatalyst layer, and therefore the photocatalyst layer also demonstrates its ability to decompose organic matter, and also decomposes organic matter inside the photocatalyst-coated resin member.

[0016] However, the photocatalyst-coated resin member of the present invention has a shielding layer formed of an inorganic material between the photocatalyst layer and the resin substrate, which prevents contact between the anatase titanium oxide particles and the resin substrate. This prevents deterioration of the resin substrate due to the photocatalytic reaction, and together with the prevention of deterioration of the photocatalyst layer itself, allows the member to exhibit self-cleaning properties over a long period of time.

[0017] The photocatalytic layer can be formed by applying inorganic polysilazane in which anatase type titanium oxide particles are dispersed onto the shielding layer and drying it.

[0018] The inorganic polysilazane is a precursor of silicon nitride (Si3N4) or silicon dioxide (SiO2), which is composed of silicon (Si), nitrogen (N), and hydrogen (H). It is hydrolyzed by moisture in the air and converted into SiO2, forming a glass coating.

[0019] The inorganic polysilazane can form a glass film at a low temperature of room temperature to 100° C. in an environment where light with a short wavelength of 500 nm or less is cut off.

[0020] Since the glass binder of the photocatalyst layer is derived from inorganic polysilazane, the anatase type titanium oxide particles are not exposed to high temperatures during the formation of the photocatalyst layer, and therefore the transition of the titanium oxide from the anatase type to the rutile type is prevented.

[0021] Furthermore, because the photocatalytic layer can be formed at low temperatures, there is no need to increase the particle size of the titanium oxide particles to suppress the transition from anatase to rutile, as is required with thermal spraying methods. Small anatase titanium oxide particles can be used, and the specific surface area of ​​the anatase titanium oxide particles can be increased, resulting in a high photocatalytic effect.

[0022] When the anatase type titanium oxide particles have an average secondary particle size of 10 to 100 nm, a high photocatalytic effect can be obtained.

[0023] Furthermore, the photocatalytic effect can be further improved by exposing anatase type titanium oxide particles on the surface of the photocatalytic layer, for example, by polishing the surface of the photocatalytic layer with diamond abrasive grains.

[0024] In addition, if the anatase type titanium oxide particles are copper-supported particles, they exhibit a photocatalytic effect not only with ultraviolet light but also with visible light, and therefore can be used preferably indoors where there is little ultraviolet light, since they can be imparted with self-cleaning properties. An example of such titanium oxide particles is TKP-103 manufactured by Teika.

[0025] The photocatalyst layer can contain an inorganic pigment as needed, which allows the photocatalyst layer to be colored in various colors, and in combination with the gloss and luster of the photocatalyst layer formed from the glass binder, the design of the photocatalyst-coated resin member can be improved.

[0026] There are no particular restrictions on the thickness of the photocatalytic layer, but if it is 10 nm to 1 μm, scratch resistance can be improved by the hard glass binder.

[0027] The inorganic material constituting the shielding layer can be one that is not deteriorated by the photocatalytic reaction and does not exhibit a photocatalytic reaction, that is, metals, alloys, and ceramics other than titanium oxide.

[0028] The metal or alloy shielding layer can be formed by plating or by a cold spray method in which metal or alloy particles are sprayed onto a resin substrate in a non-molten state. The ceramic-containing shielding layer can be formed by spraying metal or alloy particles as a binder together with ceramic particles onto a substrate by a cold spray method, or by applying and drying an inorganic polysilazane.

[0029] The photocatalyst-coated resin member of the present invention has a photocatalyst layer formed from a glass binder, and has a glossy and lustrous appearance, making it excellent in design.In addition, since the shielding layer can be seen through the transparent photocatalyst layer, it is possible to change the color tone of the photocatalyst-coated resin member by changing the shielding layer.

[0030] Specifically, the color of the photocatalyst-coated resin member can be changed by forming the shielding layer from a colored metal such as (Cu) or chromium (Cr), or from an alloy such as Cu-Zn or Cu-Ni-Zn. Also, by forming the shielding layer from a transparent glass film, the color of the resin substrate can be seen through the photocatalyst layer and the shielding layer, allowing for free decoration.

[0031] As described above, the photocatalyst-coated resin member of the present invention has self-cleaning properties, and therefore can be preferably used for automobile resin members such as steering wheels and door handles that are prone to adhesion of sebum stains, as well as for transport equipment resin members, electronic equipment resin members, home appliance resin members, office supplies resin members, residential use resin members, sanitary goods resin members, and medical equipment resin members. [Example]

[0032] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0033] [Example 1] A decorative Cr plating was applied on the resin substrate to form a shielding layer. Onto the above shielding layer, polysilazane (Zeus Clear, manufactured by Nippon Coating Co., Ltd.) containing anatase TiO2 particles (AMT-100, manufactured by Teika Co., Ltd.; secondary particle diameter 0.1 μm or less, UV-responsive), Cu-loaded anatase TiO2 particles (TKP-103, manufactured by Teika Co., Ltd.; visible light-responsive), and blue inorganic pigment was applied and dried to form a photocatalyst layer, yielding a photocatalyst-coated resin part. This photocatalyst-coated resin part showed no deterioration due to photocatalytic reaction and maintained its photocatalytic effect over the long term. [Explanation of symbols]

[0034] 1 Photocatalytic coating 2 Photocatalyst layer 3 Shielding layer 4. Resin substrate

Claims

1. A photocatalyst-coated resin member having a photocatalyst coating on the surface of a resin substrate, the photocatalytic coating has a photocatalytic layer and a shielding layer in this order from the surface side, the photocatalyst layer is a layer in which anatase-type titanium oxide particles are dispersed in a glass binder, A photocatalyst-coated resin member characterized in that the shielding layer is a layer that prevents contact between the anatase type titanium oxide particles and the resin substrate, and is formed from an inorganic material consisting of at least one material selected from the group consisting of metals, alloys, and ceramics.

2. 2. The photocatalyst coated resin member according to claim 1, wherein the glass binder is derived from inorganic polysilazane.

3. 2. The photocatalyst-coated resin member according to claim 1, wherein at least a part of the anatase type titanium oxide particles in the photocatalyst layer are exposed on the surface.

4. 2. The photocatalyst-coated resin member according to claim 1, wherein the photocatalyst layer further contains an inorganic pigment.

5. 2. The photocatalyst-coated resin member according to claim 1, which is one selected from the group consisting of resin members for automobiles, resin members for transportation equipment, resin members for electronic devices, resin members for home appliances, resin members for office supplies, resin members for housing, resin members for sanitary products, and resin members for medical equipment.

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