WO2022270283A1

WO2022270283A1 - Coated metal sheet

Info

Publication number: WO2022270283A1
Application number: PCT/JP2022/022754
Authority: WO
Inventors: 史生柴尾; 恵利春田; 三鶴西畑; 隆雄金井
Original assignee: 日本製鉄株式会社
Priority date: 2021-06-25
Filing date: 2022-06-06
Publication date: 2022-12-29
Also published as: CN117255744A; TW202304705A; JPWO2022270283A1; KR20230148209A

Abstract

[Problem] To further improve the photocatalytic effect while reducing costs. [Solution] A coated metal sheet according to the present invention has a coating layer on at least one surface of the metal sheet and has a first coating layer that is positioned on the outermost surface of the coating layer on the at least one surface of the metal sheet and that contains at least a compound having photocatalytic activity. The average thickness of the first coating layer is 0.05-5.00 µm. The total thickness from the surface of the metal plate to the outermost surface of the coating layer is 15.00 µm or less. The 60° specular glossiness of the coated metal sheet as defined by JIS Z8741:1997 is 80% or more.

Description

painted metal plate

The present invention relates to a painted metal plate.

Due to the impact of the new coronavirus (COVID-19) that has been around for several years, there is a growing need to impart antiviral properties to various items. business is booming. Although it is possible to apply agents with antiviral effects to existing buildings, the labor cost required for application is high, and the durability of the agents is not sufficient, so regular application is required. As a result, there is a problem that the running cost is high.

On the other hand, for example, as in Patent Document 1 below, conventionally, there is a known technique for imparting an antiviral function to steel materials in advance. This technique is a technique in which a protective layer and a photocatalyst layer are sequentially formed on the coated steel material on the base of the coated steel material.

Japanese Patent Application Laid-Open No. 2009-131960

However, as a result of studies by the present inventors, it was found that there is room for further improvement in the photocatalyst effect realized by the photocatalyst layer in the technology using the photocatalyst disclosed in Patent Document 1 above. .

Based on such knowledge, the object of the present invention is to provide a coated metal plate that can further improve the photocatalytic effect while suppressing the cost.

In order to solve the above problems, the present inventors have conducted extensive studies and found that, in the conventional technology disclosed in Patent Document 1, the light incident on the surface of the steel material contributes to the expression of the photocatalytic effect. It has been found that only the incident light to the steel material is doing. Based on this knowledge, as a result of further studies, if it is possible to reflect the incident light on the surface of the metal plate with higher efficiency and contribute to the expression of the photocatalytic effect for the reflected light, the photocatalytic effect can be achieved. The present invention has been completed based on the idea that it is possible to further improve it.
The gist of the present invention completed based on such knowledge is as follows.

(1) A coated metal plate having a coating layer on at least one surface of the metal plate, wherein the coating layer is located on the outermost surface of the coating layer on at least one surface of the metal plate and has photocatalytic activity. It has a first coating layer containing at least a compound, and the average thickness of the first coating layer is 0.05 to 5.00 μm, and the total thickness from the surface of the metal plate to the outermost surface of the coating layer A coated metal sheet having a thickness of 15.00 µm or less and having a 60° specular gloss of 80% or more as defined in JIS Z8741:1997.
(2) The first coating layer further contains at least one element of Si or Zr, and the total concentration of the elements is 5 to 50 in terms of silica for Si and zirconia for Zr. % by mass, the coated metal sheet according to (1).
(3) The coating layer further includes a second coating layer located below the first coating layer and made of an inorganic component containing at least one element selected from Si and Zr. The coated metal sheet according to (1) or (2), wherein the second coating layer has an average thickness of 0.10 to 5.00 μm.
(4) The coated metal sheet according to (3), wherein the second coating layer further contains an inorganic component having at least one element of P or V.
(5) The coated metal sheet according to (3) or (4), wherein the ratio of the average thickness of the second coating layer to the average thickness of the first coating layer is 0.3 to 12.0.
(6) As the coating layers, a third coating layer containing an organic component positioned below the first coating layer, and a fourth coating positioned between the first coating layer and the third coating layer. and a layer, wherein the average thickness of the third coating layer is 0.10 to 5.00 μm, and the average thickness of the fourth coating layer is 0.05 to 5.00 μm. The coated metal plate according to (1) or (2).
(7) The ratio of the average thickness of the third coating layer to the average thickness of the first coating layer is 0.5 to 20.0, and the fourth coating layer to the average thickness of the first coating layer The coated metal plate according to (6), wherein the ratio of the average thickness of is 0.3 to 20.0.
(8) The coated metal sheet according to any one of (1) to (7), wherein the total thickness from the surface of the metal sheet to the outermost surface of the first coating layer is 10.00 μm or less.
(9) The coated metal sheet according to any one of (1) to (8), wherein the compound having photocatalytic activity is anatase type titanium oxide.
(10) The coated metal sheet according to (9), wherein the anatase-type titanium oxide is metal-supported titanium oxide supported on at least one of Cu and Fe.
(11) The coated metal plate according to (9) or (10), wherein the concentration of the anatase-type titanium oxide in the first coating layer is 50 to 95% by mass in terms of titania.
(12) The coated metal sheet according to any one of (9) to (11), wherein the anatase-type titanium oxide has an average particle size of 5 to 200 nm.
(13) The metal plate is a galvanized steel plate, a zinc-aluminum alloy plated steel plate, a zinc-aluminum-magnesium alloy plated steel plate, an aluminum plated steel plate, a zinc-nickel alloy plated steel plate, a zinc-iron alloy plated steel plate, an aluminum plate, or , a stainless steel plate, the coated metal plate according to any one of (1) to (12).
(14) The coated metal plate according to any one of (1) to (13), wherein the surface of the metal plate has a hairline along the rolling direction of the metal plate.
(15) The coated metal plate according to any one of (1) to (13), wherein the surface of the metal plate has a spangle pattern.

As described above, according to the present invention, it is possible to further improve the photocatalytic effect while suppressing costs.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed typically an example of the structure of the coated metal plate which concerns on embodiment of this invention. It is explanatory drawing which showed typically another example of the structure of the coated metal plate which concerns on the same embodiment. It is explanatory drawing which showed typically another example of the structure of the coated metal plate which concerns on the same embodiment. It is explanatory drawing which showed typically another example of the structure of the coated metal plate which concerns on the same embodiment. It is explanatory drawing which showed typically another example of the structure of the coated metal plate which concerns on the same embodiment. It is an explanatory view for explaining a coating metal plate concerning the embodiment.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

(About painted metal plate)
<Structure of coated metal plate>
First, the structure of a coated metal plate according to an embodiment of the present invention will be described below with reference to FIGS. 1A to 2B. FIG. 1A is an explanatory view schematically showing an example of the structure of a coated metal plate according to this embodiment. 1B to 2B are explanatory diagrams schematically showing another example of the structure of the coated metal plate according to this embodiment.

As schematically shown in FIG. 1A, a coated metal plate 1 according to an embodiment of the present invention has a coating layer on at least one surface of the metal plate. As a layer, it has at least a photocatalyst layer 20 as an example of a first coating layer. At first glance, it may be possible to use a hard resin base material such as melamine resin instead of the metal plate as the base material. However, it is important to use a substrate that can be processed in various ways, and in this embodiment, a metal plate is used as the substrate.

[Regarding the metal plate 10]
In the coated metal plate 1 according to this embodiment, various metal plates can be used as the metal plate 10 that is the base material. Examples of such metal sheets include galvanized steel sheets, zinc-aluminum alloy plated steel sheets, zinc-aluminum-magnesium alloy plated steel sheets, aluminum plated steel sheets, zinc-nickel alloy plated steel sheets, zinc-iron alloy plated steel sheets, aluminum plates, A stainless steel plate etc. can be mentioned.

By using the metal plate as described above, it is possible to efficiently reflect the light incident on the coated metal plate 1 (in particular, the light in the ultraviolet to visible light band) on the surface of the metal plate 10 . As a result, in the coated metal plate 1 according to the present embodiment, it is possible to use the reflected light reflected by the surface of the metal plate 10 for photocatalytic reaction, as will be described later. Among the above metal plates, zinc-aluminum-magnesium alloy plated steel plate, stainless steel plate, aluminum plated steel plate, zinc plated steel plate, zinc-aluminum alloy plated steel plate, etc. can efficiently reflect incident light, so they are particularly preferred. In addition, a plated surface having a design such as a hairline or spangle pattern is suitable because it can also be used as an exterior component.

Here, the thickness of the metal plate 10 as described above is not particularly limited. can be set as appropriate.

In addition, the surface of the metal plate 10 (when using a metal plate to which various types of plating are applied as the metal plate 10, the plated surface) has a hairline pattern along the rolling direction of the metal plate, a spangle Various patterns such as patterns may be present. By providing such a pattern, it is possible to further improve the design of the coated metal plate 1 . Further, the design processing itself for providing such a pattern on the surface of the metal plate 10 contributes to further improvement of the 60° specular gloss as described below.

For example, focus on the plated metal plate 10 . In general, when plating the surface of a metal substrate, an electroplating method or a hot-dip plating method can be employed. Depending on the plating method employed, fine particles are generated on the plated surface, and as a result, the glossiness of the surface of the plated metal plate 10 (that is, the glossiness of the plated surface) may decrease. However, by subjecting the surface of such plating to hairline processing, the surface of the plating is scraped, and as a result, the reflectance of light on the surface of the plating is improved, making it possible to improve the glossiness of the surface. In addition, as a result of plating so as to form a spangle pattern, the crystal orientation of the plating that reflects light more easily appears on the surface, improving the reflectance of light on the plating surface and increasing the surface gloss can be improved.

As described in detail below, in the coated metal plate 1, the thickness of the photocatalyst layer 20 as the first coating layer, and the thickness of the photocatalyst layer 20 as the first coating layer from the surface of the metal plate 10 in the coated metal plate 1 The total thickness up to the outermost surface is controlled to be in a specific state. On top of that, design processing such as the hairline pattern and spangle pattern as described above is further applied, and such design processing also acts to further improve the 60° specular glossiness as described below. do. As for the method for forming such a pattern, various known processing methods can be appropriately used.

[About the photocatalyst layer 20]
In the coated metal plate 1 according to the present embodiment, the photocatalyst layer 20 as an example of the first coating layer is the outermost surface of the coating layer on at least one surface of the metal plate 10, as schematically shown in FIG. 1A and contains at least a compound having photocatalytic activity (hereinafter sometimes abbreviated as "photocatalytic compound"). Since the photocatalyst layer 20 contains a compound having photocatalytic activity, the compound having such photocatalytic activity causes a photocatalytic reaction by light (in particular, light in the ultraviolet to visible light band) incident on the photocatalyst layer 20. As a result, in the photocatalyst layer 20 according to the present embodiment, various photocatalyst effects including antiviral effects and bactericidal effects are exhibited. As a result, the coated metal plate 1 according to this embodiment can achieve various properties including antiviral effects and bactericidal effects.

Compounds having such photocatalytic activity mainly react with light in the ultraviolet light band (more specifically, by being excited by light in the ultraviolet light band) and exhibit photocatalytic activity, and compounds that mainly exhibit visible light. and a compound that reacts with light in the optical band (more specifically, is excited by light in the visible band) and exhibits photocatalytic activity.

Examples of the compound that reacts with light in the ultraviolet band to exhibit photocatalytic activity include titanium oxide (more specifically, anatase-type titanium oxide), zinc oxide, cerium oxide, tin oxide, bismuth oxide, zirconium oxide, oxide Tungsten, chromium oxide, molybdenum oxide, iron oxide, nickel oxide, ruthenium oxide, cobalt oxide, copper oxide, manganese oxide, germanium oxide, lead oxide, cadmium oxide, vanadium oxide, niobium oxide, tantalum oxide, rhodium oxide, rhenium oxide, etc. , metal sulfides such as cadmium sulfide and zinc sulfide, and titanium compounds such as strontium titanate and barium titanate. Among them, anatase titanium oxide, zinc oxide, tin oxide, zirconium oxide, tungsten oxide, iron oxide, niobium oxide, strontium titanate, etc. are particularly preferred as compounds that react with light in the ultraviolet light band to exhibit photocatalytic activity. It is preferably used, and anatase titanium oxide is more preferably used.

Further, the compound that reacts with light in the visible light band to exhibit photocatalytic activity includes, for example, metal-supported titanium oxide supported on at least one of Cu and Fe (more specifically, anatase type titanium oxide), anatase-type titanium oxide supported on Cr, V, Mn, Ni, Pt, anatase-type titanium oxide doped with anions such as nitrogen and sulfur, solid solutions of _AgNbO3 and SrTiO3 _, and the like. . Among them, anatase-type titanium oxide supported on at least one of Cu and Fe is particularly preferably used.

Among such photocatalyst compounds, the average particle size (primary particle size) of anatase-type titanium oxide (including those in a metal-supported state) is preferably 5 nm or more. When the average particle size (primary particle size) of the anatase-type titanium oxide is 5 nm or more, the anatase-type titanium oxide can be dispersed more uniformly in the photocatalyst layer 20 . The average particle size (primary particle size) of anatase-type titanium oxide is more preferably 20 nm or more. The average particle size (primary particle size) of the anatase-type titanium oxide (including those in a metal-supported state) is preferably 200 nm or less. By setting the average particle diameter (primary particle diameter) of the anatase titanium oxide to 200 nm or less, the anatase titanium oxide is more uniformly distributed in the photocatalyst layer 20 while suppressing excessive aggregation of the anatase titanium oxide in the photocatalyst layer 20. can be distributed. The average particle size (primary particle size) of anatase-type titanium oxide is more preferably 100 nm or less.

Here, the average particle size of the anatase-type titanium oxide can be measured, for example, by a dynamic light scattering method using laser light. Such a method can easily obtain highly accurate measurement values. However, if the particles of anatase-type titanium oxide are aggregated to some extent, the size of the aggregates (aggregate particle size) may be measured. It is preferable to check the primary particle size. When the presence of aggregated particles is confirmed as a result of TEM observation, it is preferable to change the dispersion conditions and perform measurement again by the dynamic light scattering method. If it is difficult to completely disperse the particles to the level of the primary particles, the size of the primary particles observed and measured with a TEM can be used as the primary particle size. In this case, the experience of the present inventor has shown that a representative value of all particles can be obtained by measuring approximately 100 or more arbitrarily selected particles.

In addition, for the coated metal plate 1 on which the photocatalyst layer 20 has already been formed, when measuring the average particle size of the anatase-type titanium oxide contained in the photocatalyst layer 20 after the fact, the following may be performed. That is, a cross section obtained by cutting the photocatalyst layer 20 along the thickness direction can be observed or analyzed using a transmission electron microscope (TEM). By using TEM, the primary particle size of the photocatalyst compound can be measured. Also, by performing EDS analysis together with TEM, the elements contained in the photocatalyst compound can be measured. Furthermore, the crystal structure of the photocatalyst compound (for example, in the case of titanium oxide, whether it is anatase type or rutile type) can be known by electron beam diffraction. Based on the experience of the present inventor, it has been found that a representative value of all particles can be obtained by measuring approximately 100 or more arbitrarily selected particles.

Here, the concentration of anatase-type titanium oxide (including metal-supported titanium oxide) in the photocatalyst layer 20 is preferably 50% by mass or more in terms of titania. When the concentration of anatase-type titanium oxide in the photocatalyst layer 20 is 50% by mass or more, various photocatalytic effects including antiviral effects can be reliably exhibited. The concentration of anatase-type titanium oxide in the photocatalyst layer 20 is more preferably 60% by mass or more in terms of titania. The concentration of anatase-type titanium oxide (including metal-supported titanium oxide) in the photocatalyst layer 20 is preferably 95% by mass or less in terms of titania. By setting the concentration of anatase-type titanium oxide in the photocatalyst layer 20 to 95% by mass or less, it is possible to exhibit various photocatalytic effects such as an antiviral effect while suppressing an increase in manufacturing costs. The concentration of anatase-type titanium oxide in the photocatalyst layer 20 is more preferably 80% by mass or less in terms of titania.

Also, photocatalyst compounds other than anatase-type titanium oxide preferably have an average particle size of 5 to 200 nm, and the concentration thereof is preferably 50 to 95% by mass.

Photocatalyst compounds represented by anatase-type titanium oxide and the like as described above include not only particulate substances, but also sol substances that cannot be said to be particulate, substances produced by heating metal complexes, and the like. can also be used as needed.

In addition, the photocatalyst layer 20 further contains at least one element of Si or Zr, and the total concentration of such elements is 5% by mass or more in terms of silica for Si and zirconia for Zr. is preferred. In other words, the photocatalyst layer 20 is an inorganic film having a three-dimensional network structure inorganic component skeleton containing at least one element of Si or Zr and, in some cases, impurities. Alternatively, the total concentration of at least one element of Zr is preferably 5% by mass or more in terms of silica for Si and zirconia for Zr. By containing at least one element of Si or Zr at the above concentration, it is possible to realize the photocatalyst layer 20 having more excellent corrosion resistance. The total content of at least one element selected from Si and Zr is more preferably 10% by mass or more. In addition, the photocatalyst layer 20 further contains at least one element of Si or Zr, and the total concentration of such elements is 50% by mass or less in terms of silica for Si and zirconia for Zr. is preferred. By containing at least one element of Si or Zr at the above concentration, it is possible to realize the photocatalyst layer 20 having more excellent corrosion resistance. The total content of at least one element selected from Si and Zr is more preferably 40% by mass or less. Here, Si or Zr to be contained preferably has excellent light transmittance, and is preferably an inorganic component that is less susceptible to decomposition by photocatalyst. Examples of such inorganic components containing Si and Zr include silica and zirconia.

The photocatalyst layer 20 containing the above photocatalyst compound may contain an antibacterial agent, an adsorbent such as activated carbon or zeolite, if necessary, as long as the effects of the present invention are not impaired.

The average thickness d ₁ of the photocatalyst layer 20 (in the case of the layer structure shown in FIG. 1A, the total thickness d from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20 (can also be regarded as the outermost surface of the coating layer). _T ) is 0.05 μm or more. When the _average thickness d1 of the photocatalyst layer 20 is less than 0.05 μm, it becomes difficult to uniformly form the photocatalyst layer 20 as described above, and the resulting photocatalytic effect is uneven, which is preferable. No. By setting the average thickness d ₁ to 0.05 μm or more, it is possible to uniformly develop a desired photocatalytic effect over the entire photocatalytic layer 20 . On the other hand, the average thickness d ₁ of the photocatalyst layer 20 (in the case of the layer structure shown in FIG. 1A, it is also the total thickness d _T from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20) is 5.00 μm or less. is. If the _average thickness d1 of the photocatalyst layer 20 exceeds 5.00 μm, the resulting photocatalytic effect is saturated, but the manufacturing cost increases, which is not preferable. In addition, since the photocatalyst layer is an inorganic coating, workability is lowered. By setting the _average thickness d1 to 5.00 μm or less, it is possible to uniformly exhibit a desired photocatalytic effect over the entire photocatalytic layer 20 while suppressing an increase in manufacturing cost and a decrease in workability.

Normally, light that passes through the photocatalyst layer 20 without impinging on the photocatalyst compound occurs with a certain probability. Conventionally, such light that does not act on the photocatalyst compound becomes light that does not have a photocatalytic effect. In the present embodiment, by reflecting such light on the surface of the metal plate 10, it is possible to increase the probability that the light incident on the photocatalyst layer 20 collides with the photocatalyst compound. Thereby, in this embodiment, the photocatalyst effect can be further improved. In the case of the layer structure shown in FIG. 1A, the total thickness _dT from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20 is naturally 15.00 μm or less. (In other words, the reflected light reflected at the interface between the metal plate 10 and the photocatalyst layer 20) can be used for the photocatalytic reaction by the photocatalytic compound, so the photocatalytic effect is further improved while suppressing the cost. be able to.

The _average thickness d1 of the photocatalyst layer 20 is preferably 0.10 μm or more, more preferably 0.15 μm or more. Also, the _average thickness d1 of the photocatalyst layer 20 is preferably 2.00 μm or less, more preferably 1.00 μm or less.

[60° specular gloss]
In the coated metal plate ₁ having the layer structure as shown in FIG. The 60° specular gloss defined by JIS Z8741:1997 measured from the side provided with is 80% or more. In other words, the coated metal plate 1 according to the present embodiment has a 60° specular glossiness of 80% or more as described above, so that the reflected light generated at the interface between the metal plate 10 and the photocatalyst layer 20 can be effectively It can be used for , and exhibits excellent antiviral performance. Although the light colliding with the photocatalyst is not detected as reflected light, such light is a very small part of the whole in the coating structure of the present invention. Therefore, even considering the decrease due to the photocatalyst, it can be determined that the antiviral property is excellent if the 60° specular glossiness specified in the present invention is 80% or more. In the coated metal plate 1 according to this embodiment, the 60° specular glossiness is preferably 90% or more, more preferably 130% or more. Although the upper limit of the 60° specular glossiness is not particularly specified, it is difficult to exceed 200%, and such a value is considered to be the substantial upper limit. The 60° specular gloss can be measured using a gloss meter conforming to the JIS standard.

<Modification>
The coated metal plate 1 according to the present embodiment, which has a layer structure as shown in FIG. 1A, has a further coating layer that functions as a chemical conversion coating layer between the metal plate 10 and the photocatalyst layer 20. may By providing a chemical conversion coating layer between the metal plate 10 and the photocatalyst layer 20, the adhesion between the metal plate 10 and the photocatalyst layer 20 can be further improved. Furthermore, it is also possible to further improve the corrosion resistance and the like of the coated metal plate 1 according to the present embodiment.

In the coated metal plate 1 according to the present embodiment, when a chemical conversion coating layer is further provided, the following two types of layer configurations are realized according to the type of compound component constituting the chemical conversion coating layer. is preferred. Hereinafter, with reference to FIGS. 1B to 3, the layer structure of a coated metal sheet having a chemical conversion film layer will be described in detail.
1B to 2 are explanatory diagrams schematically showing another example of the structure of the coated metal plate according to this embodiment. FIG. 3 is an explanatory diagram for explaining the coated metal plate according to this embodiment.

[When providing an inorganic chemical conversion coating layer]
FIGS. 1B and 1C are schematic views schematically showing the layer structure of the coated metal plate 1 when an inorganic chemical conversion coating layer made of inorganic components is provided as the chemical conversion coating layer.
In this case, the coated metal plate 1 according to the present embodiment has an inorganic chemical conversion coating layer 30 as an example of the second coating layer between the metal plate 10 and the photocatalyst layer 20 as described above.

Photocatalyst compounds typified by anatase-type titanium oxide have extremely excellent oxidizing properties, so when a coating layer is provided on the lower layer side than the layer in which the photocatalyst compound is present, protection for protecting such coating layer It often forms layers. However, as described below, by forming the chemical conversion coating layer from an inorganic component, it becomes possible to dispose the chemical conversion coating layer without providing a protective layer.

The inorganic chemical conversion treatment film layer 30 is formed by chemical conversion treatment after removing impurities such as oil and surface oxides adhering to the surface of the metal plate 10 by a known degreasing process and washing process. Preferably, the inorganic chemical conversion coating layer 30 is made of an inorganic component containing at least one element of Si and Zr. In addition, the inorganic chemical conversion treatment film layer 30 may further contain an inorganic component containing at least one of P and V elements.

When the inorganic chemical conversion coating layer 30 contains the inorganic components having the above elements, the film-forming properties after application of the chemical conversion treatment liquid and the barrier properties of the coating against corrosive factors such as moisture and corrosive ions ( Denseness) and adhesion of the film to the surface of the metal plate are improved, contributing to raising the corrosion resistance of the film.

Examples of inorganic components containing Si include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2- aminoethyl)aminopropyltriethoxysilane and the like. Examples of inorganic components containing Zr include zirconium carbonate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium carbonate, and ammonium zirconium carbonate.

Examples of inorganic components containing P include phosphoric acids such as phosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid and tetraphosphoric acid, salts thereof, ammonium dihydrogen phosphate, and the like. be able to. Examples of inorganic components containing V include ammonium metavanadate (V), potassium metavanadate (V), sodium metavanadate (V), and vanadyl sulfate (IV).

In the inorganic chemical conversion treatment film layer 30 according to the present embodiment, it is possible to use the various inorganic components described above either singly or in combination. In addition, the content of various inorganic components as described above may also be adjusted as appropriate.

The average thickness d2 of the inorganic chemical conversion coating layer 30 is preferably 0.10 μm or _more , more preferably 0.20 μm or more. As a result, while uniformly forming the inorganic chemical conversion coating layer 30 on the surface of the metal plate 10, it is possible to stably exhibit the various effects of providing the chemical conversion coating layer as described above. . Also, the _average thickness d2 of the inorganic chemical conversion coating layer 30 is preferably 5.00 μm or less, more preferably 1.00 μm or less. As a result, while uniformly forming the inorganic chemical conversion coating layer 30 on the surface of the metal plate 10, it is possible to stably exhibit the various effects of providing the chemical conversion coating layer as described above. .

In addition, the ratio (d ₂ /d ₁ ) of the average thickness d ₂ of the inorganic chemical conversion coating layer 30 to the average thickness d ₁ of the photocatalyst layer 20 is preferably 0.3 or more, and is 0.5 or more. It is more preferable to have This makes it possible to further improve the working adhesion. In addition, the ratio (d ₂ /d ₁ ) of the average thickness d ₂ of the inorganic chemical conversion coating layer 30 to the average thickness d ₁ of the photocatalyst layer 20 is preferably 12.0 or less, and 5.0 or less. It is more preferable to have This makes it possible to further improve the working adhesion.

Further, the coated metal plate 1 according to the present embodiment, as schematically shown in FIG. It may further have various known layers, including layers and the like.

Here, even in the case shown in FIGS. 1B and 1C, the total thickness d _T (=d ₁ +d ₂ +α) shall be 15.00 μm or less. As a result, as schematically shown in FIG. 3, the reflected light reflected by the surface of the metal plate 10 (in other words, the interface between the metal plate 10 and the photocatalyst layer 20) is converted into a photocatalyst by the photocatalyst compound. Since it can be used for the reaction, it is possible to further improve the photocatalytic effect while suppressing an increase in cost. A total thickness d _T (=d ₁ +d ₂ +α) from the surface of the metal plate 10 to the outermost surface of the coating layer is preferably 10.00 μm or less, more preferably 7.00 μm or less.

1B and 1C, the 60° specular gloss defined by JIS Z8741:1997, which is measured from the side on which the photocatalyst layer 20 is provided, of the coated metal plate 1 is 80% or more. becomes. Here, if the total thickness _dT is 15.00 μm or less and the 60° specular glossiness is 80% or more, the incident light reflected on the surface of the metal plate 10 is treated as a photocatalyst by the photocatalyst compound. It can be considered that it is used for the reaction.

[When providing an organic chemical conversion coating layer]
2A and 2B are schematic views schematically showing the layer structure of the coated metal plate 1 when an organic chemical conversion coating layer containing an organic component is provided as the chemical conversion coating layer.
In this case, the coated metal plate 1 according to the present embodiment includes an organic chemical conversion treatment film layer 40 as an example of a third film layer and a fourth film between the metal plate 10 and the photocatalyst layer 20 as described above. and a protective layer 50 as an example of a layer.

<<Organic chemical conversion treatment film layer 40>>
The organic chemical conversion coating layer 40 is a layer located below the photocatalyst layer 20 (more specifically, the surface of the metal plate 10), and removes impurities such as oil adhering to the surface of the metal plate 10 and surface oxides. , is formed by chemical conversion treatment after removal by known degreasing and washing processes.

The organic chemical conversion treatment film layer 40 according to the present embodiment includes, for example, resins, silane coupling agents, zirconium compounds, silica, phosphoric acid and salts thereof, fluorides, vanadium compounds, and a group consisting of tannin or tannic acid. Any one or more selected from may be contained. By containing these substances, it is possible to further improve the film-forming property after applying the chemical conversion treatment solution, the barrier property (denseness) of the film against corrosion factors such as moisture and corrosive ions, and the film adhesion to the surface of the metal plate. etc., and contributes to raising the corrosion resistance of the film.

In particular, when the organic chemical conversion treatment film layer 40 contains one or more of a silane coupling agent or a zirconium compound, a crosslinked structure is formed in the organic chemical conversion treatment film layer 40, and the surface of the metal plate is formed. Since bonding is also strengthened, it is possible to further improve the adhesion and barrier properties of the film.

In addition, when the organic chemical conversion treatment film layer 40 contains at least one of silica, phosphoric acid and its salts, fluoride, or vanadium compound, it functions as an inhibitor, and a precipitated film or passivation film is formed on the surface of the metal plate. By forming a film, it becomes possible to further improve the corrosion resistance.

Below, the details of each constituent component that the organic chemical conversion treatment film layer 40 as described above may contain will be described with examples.

[resin]
Examples of resins that can be used include known organic resins such as polyester resins, polyurethane resins, epoxy resins, phenol resins, acrylic resins, and polyolefin resins. In order to further improve the adhesion to the metal plate, it is preferable to use at least one resin (polyester resin, urethane resin, epoxy resin, acrylic resin, etc.) having a forced site or a polar functional group in the molecular chain. . The resin may be used alone or in combination of two or more.

The content of the resin in the organic chemical conversion coating layer 40 is, for example, preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the coating. Thereby, corrosion resistance can be improved. In addition, the content of the resin in the organic chemical conversion coating layer 40 is, for example, preferably 85% by mass or less, more preferably 60% by mass or less, and 40% by mass or less relative to the solid content of the coating. is more preferable. By setting the resin content to 85% by mass or less, it is possible to improve the corrosion resistance of the coating while ensuring the performance required of the coating other than the corrosion resistance.

[Silane coupling agent]
Silane coupling agents include, for example, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane. , γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ- methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldiethoxy Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane , γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropylmethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-ani linopropylmethyldimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropylmethyldiethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, octadecyldimethyl [3 -(trimethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldimethoxysilyl)propyl]ammonium chloride, octade sildimethyl[3-(triethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldiethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, Examples include dimethyldichlorosilane and trimethylchlorosilane. The addition amount of the silane coupling agent in the chemical conversion treatment agent for forming the organic chemical conversion treatment film layer 40 can be, for example, 2 to 80 g/L. By setting the addition amount of the silane coupling agent to 2 g/L or more, it is possible to improve the adhesion to the surface of the metal plate and improve the processing adhesion of the coating film. Further, by setting the amount of the silane coupling agent added to 80 g/L or less, it is possible to maintain the cohesive force of the chemical conversion film and improve the processing adhesion of the coating film. The silane coupling agents as exemplified above may be used alone or in combination of two or more.

[Zirconium compound]
Examples of zirconium compounds include zirconium normal propylate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium monoethylacetoacetate, zirconium acetylacetonate bisethylacetoacetate, Zirconium acetate, zirconium monostearate, zirconium carbonate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium carbonate and the like can be mentioned. The amount of the zirconium compound added in the chemical conversion treatment agent for forming the organic chemical conversion treatment film layer 40 can be, for example, 2 to 80 g/L. By setting the addition amount of the zirconium compound to 2 g/L or more, it is possible to improve the adhesion to the surface of the metal plate and to improve the processing adhesion of the coating film. Further, by setting the amount of the zirconium compound to be added to 80 g/L or less, it is possible to maintain the cohesive force of the chemical conversion film and improve the processing adhesion of the coating film. Such zirconium compounds may be used alone or in combination of two or more.

[silica]
Examples of silica include commercially available products such as "Snowtex N", "Snowtex C", "Snowtex UP", and "Snowtex PS" manufactured by Nissan Chemical Industries, Ltd., and "Adelite AT-20Q" manufactured by ADEKA Corporation. or powdered silica such as Aerosil #300 manufactured by Nippon Aerosil Co., Ltd. can be used. Silica can be appropriately selected according to the required performance of the coated metal sheet. The amount of silica added to the chemical conversion agent for forming the organic chemical conversion coating layer 40 is preferably 1 to 40 g/L. By setting the amount of silica to be added to 1 g/L or more, it is possible to improve the processing adhesion of the coating film. Further, by setting the amount of silica to be added to 40 g/L or less, it is possible to achieve both effects of working adhesion and corrosion resistance while suppressing an increase in cost.

[Phosphoric acid and its salts]
Examples of phosphoric acid and salts thereof include phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid and tetraphosphoric acid and salts thereof, ammonium salts such as triammonium phosphate and diammonium hydrogen phosphate, Phosphonic acids such as aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) and their salts, organic phosphoric acids such as phytic acid and salts thereof. Examples of salts of phosphoric acid other than ammonium salts include metal salts with Na, Mg, Al, K, Ca, Mn, Ni, Zn, Fe, and the like. Phosphoric acid and its salt may be used alone or in combination of two or more.

The content of phosphoric acid and its salt is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the film. Also, the content of phosphoric acid and its salt is preferably 20% by mass or less, more preferably 10% by mass or less, relative to the coating solid content. When the content of phosphoric acid and its salts is 20% by mass or less, embrittlement of the film can be prevented, and deterioration of the working adhesion of the film during molding of the coated metal sheet can be prevented. .

[Fluoride]
Examples of fluorides include ammonium zircon fluoride, ammonium silicofluoride, ammonium titanium fluoride, sodium fluoride, potassium fluoride, calcium fluoride, lithium fluoride, titanium hydrofluoric acid, and zircon hydrofluoric acid. . Such fluorides may be used alone or in combination of two or more.

The content of fluoride is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the film. The content of fluoride is preferably 20% by mass or less, more preferably 10% by mass or less, relative to the solid content of the film. When the content of fluoride is 20% by mass or less, embrittlement of the film can be prevented, and deterioration of working adhesion of the film during molding of the coated metal sheet can be prevented.

[Vanadium compound]
Examples of vanadium compounds include vanadium pentoxide, metavanadic acid, ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride, and other vanadium compounds obtained by reducing pentavalent vanadium compounds to divalent to tetravalent vanadium trioxide. , vanadium dioxide, vanadium oxysulfate, vanadium oxyoxalate, vanadium oxyacetylacetonate, vanadium acetylacetonate, vanadium trichloride, phosphovanadomolybdic acid, vanadium sulfate, vanadium dichloride, vanadium oxide, etc. A vanadium compound etc. can be mentioned. Such vanadium compounds may be used alone or in combination of two or more.

The content of the vanadium compound is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the film. Moreover, the content of the vanadium compound is preferably 20% by mass or less, more preferably 10% by mass or less, relative to the solid content of the film. When the content of the vanadium compound is 20% by mass or less, embrittlement of the film can be prevented, and deterioration of working adhesion of the film during molding of the coated metal sheet can be prevented.

[Tannin or tannic acid]
Both hydrolyzable tannin and condensed tannin can be used as tannin or tannic acid. Examples of tannins and tannic acids include hamameta tannins, quintuple tannins, gallic tannins, myrobalan tannins, divisibi tannins, algarovira tannins, valonia tannins, catechins, and the like. The amount of tannin or tannic acid added to the chemical conversion agent for forming the organic chemical conversion coating layer 40 can be 2 to 80 g/L. By setting the amount of tannin or tannic acid added to 2 g/L or more, the adhesion to the metal plate surface can be improved, and the processing adhesion of the coating film can be improved. Further, by setting the amount of tannin or tannic acid to be added to 80 g/L or less, the cohesive force of the chemical conversion film can be maintained, and the processing adhesion of the coating film can be improved.

Also, an acid, an alkali, or the like may be added to the chemical conversion treatment agent for forming the organic chemical conversion treatment film layer 40 for pH adjustment within a range that does not impair the performance.

The _average thickness d3 of the organic chemical conversion coating layer 40 is preferably 0.10 μm or more, more preferably 0.20 μm or more, and even more preferably 0.30 μm or more. As a result, while the organic chemical conversion coating layer 40 is formed uniformly on the surface of the metal plate 10, various effects of providing the chemical conversion coating layer as described above can be stably exhibited. . Also, the _average thickness d3 of the organic chemical conversion coating layer 40 is preferably 5.00 μm or less, more preferably 4.00 μm or less, and even more preferably 3.00 μm or less. As a result, while the organic chemical conversion coating layer 40 is formed uniformly on the surface of the metal plate 10, various effects of providing the chemical conversion coating layer as described above can be stably exhibited. .

In addition _, the ratio ₍ d3/d1) of the _average thickness d3 of the organic chemical conversion coating layer 40 to the _average thickness d1 of the photocatalyst layer 20 is preferably 0.5 or more, and 2.0 or more. It is more preferable to have This makes it possible to further improve the adhesion of the processed portion. In addition _, the ratio ₍ d3/d1) of the _average thickness d3 of the organic chemical conversion coating layer 40 to the _average thickness d1 of the photocatalyst layer 20 is preferably 20.0 or less, and 10.0 or less. It is more preferable to have This makes it possible to further improve the adhesion of the processed portion.

<<Protective layer 50>>
The protective layer 50 is a layer provided between the photocatalyst layer 20 and the organic chemical conversion treatment film layer 40 (more preferably directly under the photocatalyst layer 20), and is protected from the oxidizing power of the photocatalyst compound contained in the photocatalyst layer 20. , are provided to protect layers located below the photocatalyst layer 20 .

Here, the specific components of the protective layer 50 can contain various known components. Examples of such components include inorganic oxides such as silica and zirconia. Moreover, the specific contents of these components may also be adjusted as appropriate.

It should be noted that the protective layer 50 also preferably has excellent light transmittance, like the photocatalyst layer 20 . In order to realize the protective layer 50 having excellent light transmittance, it is possible to use, for example, the same components as the components other than the photocatalyst compound in the photocatalyst layer 20 .

The _average thickness d4 of the protective layer 50 is preferably 0.05 μm or more, more preferably 0.20 μm or more. This makes it possible to reliably protect the layers located below the protective layer 50 from the oxidizing power of the photocatalyst compound while suppressing deterioration in workability. Also, the _average thickness d4 of the protective layer 50 is preferably 5.00 μm or less, more preferably 0.60 μm or less. This makes it possible to reliably protect the layers located below the protective layer 50 from the oxidizing power of the photocatalyst compound while suppressing deterioration in workability.

In addition, the ratio (d ₄ /d ₁ ) of the average thickness d ₄ of the protective layer 50 to the average thickness d ₁ of the photocatalyst layer 20 is preferably 0.3 or more, more preferably 1.0 or more. preferable. This makes it possible to reliably suppress the decomposition of the organic chemical conversion coating layer 40 by the photocatalyst layer 20 . In addition, the ratio (d ₄ /d ₁ ) of the average thickness d ₄ of the protective layer 50 to the average thickness d ₁ of the photocatalyst layer 20 is preferably 20.0 or less, more preferably 3.0 or less. preferable. This makes it possible to reliably suppress the decomposition of the organic chemical conversion coating layer 40 by the photocatalyst layer 20 .

In addition, as schematically shown in FIG. 2B, the coated metal plate 1 according to the present embodiment has various colors, for example, between the photocatalyst layer 20 and the protective layer 50 and the organic chemical conversion coating layer 40. It may further have various known layers including a colored layer containing a pigment.

Here, even in the case shown in FIGS. 2A and 2B, the total thickness d _T (=d ₁ +d ₃ +d ₄ +α) is 15.00 μm or less. As a result, as schematically shown in FIG. 3, the reflected light reflected by the surface of the metal plate 10 (in other words, the interface between the metal plate 10 and the photocatalyst layer 20) is converted into a photocatalyst by the photocatalyst compound. Since it can be used for reactions, it is possible to further improve the photocatalytic effect while suppressing costs. A total thickness d _T (=d ₁ +d ₃ +d ₄ +α) from the surface of the metal plate 10 to the outermost surface of the coating layer is preferably 10.00 μm or less, more preferably 7.00 μm or less.

2A and 2B, the 60° specular glossiness defined by JIS Z8741:1997 measured from the side where the photocatalyst layer 20 is provided is 80% or more. Here, if the total thickness _dT is 15.00 μm or less and the 60° specular glossiness is 80% or more, the incident light reflected on the surface of the metal plate 10 is treated as a photocatalyst by the photocatalyst compound. It can be considered that it is used for the reaction.

1A to 3 illustrate the case where each layer including the photocatalyst layer 20 is provided on one side surface of the metal plate 10, but each layer including the photocatalyst layer 20 is the metal plate 10. may be provided on both sides of the In this case, the total thickness _dT from the surface of the metal plate 10 to the surface of the photocatalyst layer 20 on each surface of the coated metal plate 1 is set to 15.00 μm or less. Also, the 60° specular glossiness is 80% or more on each side of the coated metal plate 1 . Moreover, when the inorganic chemical conversion coating layer 30 described above is provided, the protective layer 50 as described above may be formed.

The coated metal plate according to the present embodiment has been described in detail above with reference to FIGS. 1A to 3.

<Method for measuring the average thickness of each layer>
Here, the average thickness of each layer including the photocatalyst layer can be measured by observing the layer of interest with a microscope from the cross-sectional direction. As a method for preparing a sample to be observed from the cross-sectional direction, known methods such as embedding in resin and polishing the observation surface, FIB processing, and microtome method can be used. Further, as the type of microscope, known devices such as SEM and TEM can be used.

(About manufacturing method of coated metal plate)
In the coated metal plate according to the present embodiment as described above, the surface of the metal plate serving as the base material is subjected to various pretreatments such as cleaning as necessary, and then the photocatalyst layer is formed. The photocatalyst treatment agent, the chemical conversion treatment agent for forming the chemical conversion coating layer, and the protective treatment agent for forming the protective layer are applied to form the desired layer structure, and then dried and baked. can do.

Here, various coating materials can be applied by generally known coating methods such as roll coating, curtain flow coating, air spray, airless spray, immersion, bar coating, and brush coating. Particularly preferred is roll coating, which is a feature of this product and enables stable coating with a thin film.

In addition, the conditions for drying and baking are not particularly limited, and may be set appropriately according to the paint used.

The coated metal sheet according to the present invention will be specifically described below while showing examples and comparative examples. The examples shown below are merely examples of the coated metal sheet according to the present invention, and the coated metal sheet according to the present invention is not limited to the following examples.

　Eight types of metal plates shown in Table 1 below were prepared as base metal plates. In Table 1, the six types of metal sheets represented by SD, ZL, GI, GL, AL, and GA are various plated steel sheets using steel sheets as base materials. The plate thickness of each metal plate, and the plating composition and coating amount/standard of each plated steel plate are shown in Table 1 below.

As compounds having photocatalytic activity (photocatalytic compounds), seven types of compounds shown in Table 2 below were prepared. Any photocatalyst compound used what is marketed. The supported metals and average particle diameters are also shown in Table 2.

<Inorganic/organic chemical conversion treatment agent>
Table 3 below shows the raw materials of the water-based paint (chemical conversion treatment agent) for forming the inorganic chemical conversion treatment film and the organic chemical conversion treatment film used, and the concentration in the dry film. The amount added was adjusted so that the concentration of each component in the dry film would be a predetermined concentration. The solid concentration of the treatment agent was adjusted by adding ion-exchanged water so that the inorganic chemical conversion treatment film had a solid content concentration of 10 mass % and the organic chemical conversion treatment film had a solid content concentration of 20 mass %. Each treatment agent was applied so as to have a dry film thickness shown in Tables 4-1 and 4-2 below. After that, the metal plate was dried in an induction heating furnace so that the reaching temperature of the metal plate was 150° C., and then water-cooled by spraying.

<Photocatalytic agent, protective agent>
The photocatalyst treatment agent used and the method for preparing the protective treatment agent will be described.
The protective treatment agent was adjusted to have a solid concentration of 8% by mass in consideration of storage stability. The concentration was adjusted by diluting with n-butanol. The photocatalyst treatment agent was prepared by adding a predetermined amount of the compound shown in Table 2 to the following protective treatment agent. The solid content concentration of the photocatalyst compound is as shown in Tables 4-1 and 4-2 below.

(1) Protective film treatment agent (Si-based): tetraethoxysilane (22.5 parts by mass), methacryloxypropyltrimethoxysilane (2.8 parts by mass), n-butanol (26 parts by mass), were mixed and stirred at 60° C. for 2 hours. While this mixture was stirred, a mixture of 26% by mass hydrochloric acid (3 parts by mass) and n-butanol (26 parts by mass) was added dropwise at a rate of 1 drop/second. After that, the mixture was kept at 60° C. for 2 hours with stirring to obtain a treating agent. A series of operations were performed in a nitrogen atmosphere.

(2) Protective film treatment agent (Zr-based): zirconium n-butoxide (34.5 parts by mass), n-butanol (11.6 parts by mass), and 1,5-diaminopentane (0.5 parts by mass) ) and yttrium nitrate (2.8 parts by mass) were mixed and stirred for 1 hour. After that, glacial acetic acid (4.8 parts by mass) was added, and the mixture was stirred for 40 hours. After that, concentrated nitric acid (0.6 parts by mass) was added dropwise at a rate of 1 drop/second and stirred for 2 hours to obtain a treating agent. A series of operations were performed in a nitrogen atmosphere.

Using the metal plate and the photocatalyst compound shown above, coated metal plates having the configurations shown in Tables 4-1 and 4-2 below were produced by roll coating. Each layer was formed on one side of the metal plate. Also, for some of the coated metal plates, the surface of the metal plate was subjected to design processing to form a hairline pattern. In addition, for some painted metal sheets, a hot-dip galvanizing bath containing 0.1% by mass of Sb and 0.2% by mass of Al is used, and by adjusting the solidification speed of the hot-dip galvanizing, spangle A patterned plated steel sheet was used as the substrate.

The average film thickness of each layer in the coated metal plate as described above was measured by embedding the obtained coated metal plate in resin and observing the observation surface obtained by polishing the cross section with a microscope. In addition, the 60° specular gloss was measured with a gloss meter (UGV-6P manufactured by Suga Test Instruments Co., Ltd.) conforming to JIS Z8741:1997.

The obtained coated metal plate was evaluated from the viewpoint of antiviral properties, processing adhesion, and corrosion resistance. Detailed evaluation methods are as follows.

<Antiviral properties>
The antiviral properties were verified by measuring the virus infectivity titer through the following antiviral test in accordance with the antiviral standards stipulated by the Antimicrobial Product Technology Council. More specifically, each coated metal plate was placed on a petri dish with the evaluation surface facing up, and a virus suspension containing influenza A virus was dropped onto the evaluation surface. After that, the coated metal plate was covered with a film to bring the virus suspension into close contact with the entire surface to be evaluated, and then the petri dish was covered with a lid. The petri dish was allowed to stand for 24 hours in a room at 25° C. with an illumination of 1000 lux, simulating a room in a general office. After that, the film surface and the evaluation surface were washed to remove viruses, and the virus infectivity titer (unit: PFU/cm ² , PFU: Plaque Forming Units) in the obtained washing solution was measured by the plaque measurement method.

Separately from the painted metal plate, each metal plate without a photocatalyst layer was also subjected to the same antiviral test. The extent to which the infectious titer decreased was evaluated as the activity value. If the virus is reduced by 10 ² or more (in other words, if the activity value is 1 × 10 ² or more), the use of the certified seal stipulated by the Antimicrobial Product Technology Council is permitted. Those with an activity value of 1×10 ² or more were judged to be acceptable. Table 5 below shows the logarithmic values of the obtained activity values.

<Processing Adhesion>
After applying 0T bending (180° bending) processing to the test material and peeling off the film on the outside of the bent part with adhesive tape (Nichiban Co., Ltd. Sellotape (registered trademark) tape width 15 mm), observe the state of film adhesion to the tape side. did. Then, the processing adhesion was evaluated according to the following evaluation criteria. In this adhesion test, the passing level was 3 or higher. Specifically, when the score was 4 or more, it was judged that the adhesiveness was excellent, and 3 or more was judged to be acceptable (acceptable level).

(Evaluation criteria)
5: No coating adhered to the tape side 4: The peeled length on the steel plate side is less than 5% of the total length of the processed part on one side of the test material in a state where several points of the coating are peeled off on the tape side 3: On the tape side The peeled length on the steel plate side is 5% or more and less than 10% with respect to the total length of the processed part on one side of the test material with several peeled coatings 2: There is peeled coating on the tape side, and the peeled length on the steel plate side is 10% or more and less than 20% of the total length of the processed part on one side of the test material. 20% or more

<Corrosion resistance>
A salt spray test (SST) in accordance with JIS Z 2371 was performed for 72 hours with the end face of the test material tape-sealed. After the end of the test, the state of rust generation on the flat portion was observed, and the corrosion resistance was evaluated according to the following evaluation criteria. The pass level was 3 or higher.

(Evaluation criteria)
5: White rust generated area is less than 1% of the total area of one side of the test material 4: White rust generated area is 1% or more and less than 5% of the total area of one side of the test material 3: White rust The generated area is 5% or more and less than 10% of the total area of one side of the test material 2: The white rust generation area is 10% or more and less than 30% of the total area of one side of the test material 1: White rust The generated area is 30% or more of the total area of one side of the test material

The results obtained are summarized in Table 5 below.
As is clear from Table 5 below, the coated metal plates corresponding to the examples of the present invention exhibit excellent antiviral properties, processing adhesion and corrosion resistance, while the coated metal plates corresponding to the comparative examples of the present invention. was unsuccessful in the evaluation results of antiviral properties or processing adhesion.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

1 coated metal plate 10 metal plate 20 photocatalyst layer (first coating layer)
30 Inorganic chemical conversion coating layer (second coating layer)
40 Organic chemical conversion coating layer (third coating layer)
50 protective layer (fourth coating layer)

Claims

A coated metal plate having a coating layer on at least one surface of the metal plate,
The coating layer has a first coating layer located on the outermost surface of the coating layer on at least one surface of the metal plate and containing at least a compound having photocatalytic activity,
The average thickness of the first coating layer is 0.05 to 5.00 μm,
The total thickness from the surface of the metal plate to the outermost surface of the coating layer is 15.00 μm or less,
The coated metal sheet has a 60° specular gloss of 80% or more as defined in JIS Z8741:1997.
The first coating layer further contains at least one element of Si or Zr,
2. The coated metal sheet according to claim 1, wherein the total concentration of the elements is 5 to 50% by mass in terms of silica for Si and zirconia for Zr.
The coating layer further comprises a second coating layer located below the first coating layer and made of an inorganic component containing at least one element of Si or Zr,
3. The coated metal sheet according to claim 1, wherein the average thickness of said second coating layer is 0.10 to 5.00 μm.
The coated metal sheet according to claim 3, wherein the second coating layer further contains an inorganic component containing at least one element of P and V.
The coated metal sheet according to claim 3 or 4, wherein the ratio of the average thickness of the second coating layer to the average thickness of the first coating layer is 0.3 to 12.0.
As the coating layer,
a third coating layer containing an organic component located below the first coating layer;
a fourth coating layer located between the first coating layer and the third coating layer;
and
The average thickness of the third coating layer is 0.10 to 5.00 μm,
3. The coated metal sheet according to claim 1, wherein the fourth coating layer has an average thickness of 0.05 to 5.00 μm.
The ratio of the average thickness of the third coating layer to the average thickness of the first coating layer is 0.5 to 20.0,
7. The coated metal sheet according to claim 6, wherein the ratio of the average thickness of said fourth coating layer to the average thickness of said first coating layer is 0.3 to 20.0.
The coated metal sheet according to any one of claims 1 to 7, wherein the total thickness from the surface of the metal sheet to the outermost surface of the first coating layer is 10.00 µm or less.
The coated metal plate according to any one of claims 1 to 8, wherein the compound having photocatalytic activity is anatase-type titanium oxide.
The coated metal plate according to claim 9, wherein the anatase-type titanium oxide is metal-supported titanium oxide supported on at least one of Cu and Fe.
The coated metal sheet according to claim 9 or 10, wherein the concentration of said anatase-type titanium oxide in said first coating layer is 50 to 95% by mass in terms of titania.
The coated metal sheet according to any one of claims 9 to 11, wherein the anatase-type titanium oxide has an average particle size of 5 to 200 nm.
The metal plate is a galvanized steel plate, a zinc-aluminum alloy plated steel plate, a zinc-aluminum-magnesium alloy plated steel plate, an aluminum plated steel plate, a zinc-nickel alloy plated steel plate, a zinc-iron alloy plated steel plate, an aluminum plate, or a stainless steel plate. The coated metal plate according to any one of claims 1 to 12, wherein
The coated metal plate according to any one of claims 1 to 13, wherein hairlines along the rolling direction of the metal plate are present on the surface of the metal plate.
The coated metal plate according to any one of claims 1 to 13, wherein a surface of said metal plate has a spangle pattern.