Coated metal sheet

Abstract

This invention relates to a coated metal plate. It further improves photocatalytic performance while reducing costs. The coated metal plate of this invention has a film layer on at least one side of the metal plate, having a first film layer located on the outermost surface of the film layer on at least one side of the metal plate and containing at least a photocatalytically active compound. The average thickness of the first film 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 film layer is less than 15.00 μm. The coated metal plate has a 60° specular gloss of 80% or more according to JIS Z8741:1997.

Description

[0001] This application is a divisional application of the application filed on June 6, 2022, with application number 202280032233.2 and invention title "Coated Metal Plate". Technical Field

[0002] This invention relates to coated metal sheets. Background Technology

[0003] In recent years, due to the impact of the novel coronavirus (COVID-19), the demand for endowing various items with antiviral properties has been increasing, leading to an unprecedented boom in the business of applying antiviral agents to the surfaces of various items. While antiviral agents can be applied to existing buildings, the labor costs required for application are high, and due to the insufficient durability of the agents, regular application is necessary, resulting in high operating costs.

[0004] On the other hand, for example, as described in Patent Document 1 below, there is a known technique for pre-conferring antiviral properties on steel. This technique is based on coated steel, on which a protective layer and a photocatalyst layer are sequentially formed in sequence.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-131960 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, the inventors' research results indicate that in the photocatalyst-based technology disclosed in Patent Document 1, there is room for further improvement in the photocatalytic effect achieved by the photocatalyst layer.

[0010] Based on this understanding, the object of the present invention is to provide a coated metal plate that can further improve the photocatalytic effect while suppressing costs.

[0011] Solution for solving the problem

[0012] To address the aforementioned problems, the inventors conducted in-depth research and discovered that, in the prior art disclosed in Patent Document 1, only the light incident on the steel surface contributes to the photocatalytic effect. Based on this discovery, further research was conducted, leading to the conclusion that if the incident light could be reflected more efficiently on the surface of the metal plate, and the reflected light could also contribute to the photocatalytic effect, the photocatalytic effect could be further improved, thus completing this invention.

[0013] The key points of the present invention, which was made based on this discovery, are as follows.

[0014] (1) A coated metal plate having a film layer on at least one side of the metal plate, wherein the film layer has a first film layer located on the outermost surface of the aforementioned film layer and containing at least a photocatalytically active compound on at least one side of the metal plate, the average thickness of the first film layer being 0.05 to 5.00 μm, the total thickness from the surface of the metal plate to the outermost surface of the film layer being 15.00 μm or less, and the coated metal plate having a 60° specular gloss of 80% or more as specified in JIS Z8741:1997.

[0015] (2) The coated metal plate according to (1), wherein the first film layer further contains at least one element of Si and Zr, and the total concentration of the element is 5 to 50 by mass for Si in terms of silicon dioxide and Zr in terms of zirconium oxide.

[0016] (3) The coated metal plate according to (1) or (2), wherein, as the coating layer, there is a second coating layer located below the first coating layer and composed of an inorganic system having at least one of Si and Zr, the average thickness of the second coating layer being 0.10 to 5.00 μm.

[0017] (4) The coated metal plate according to (3), wherein the second film layer further contains an inorganic component having at least one of P and V.

[0018] (5) The coated metal sheet according to (3) or (4), wherein the ratio of the average thickness of the second film layer to the average thickness of the first film layer is 0.3 to 12.0.

[0019] (6) The coated metal plate according to (1) or (2), wherein, as the coating layer, it further comprises a third coating layer containing organic components located below the first coating layer and a fourth coating layer located between the first coating layer and the third coating 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.

[0020] (7) The coated metal sheet according to (6), wherein the ratio of the average thickness of the third film layer to the average thickness of the first film layer is 0.5 to 20.0, and the ratio of the average thickness of the fourth film layer to the average thickness of the first film layer is 0.3 to 20.0.

[0021] (8) A 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 film layer is less than 10.00 μm.

[0022] (9) A coated metal plate according to any one of (1) to (8), wherein the photocatalytically active compound is anatase titanium oxide.

[0023] (10) The coated metal plate according to (9), wherein the anatase titanium oxide is a metal-supported titanium oxide supported on at least one of Cu and Fe.

[0024] (11) The coated metal plate according to (9) or (10), wherein the concentration of the anatase titanium oxide in the first film layer is 50 to 95% by mass in terms of titanium oxide.

[0025] (12) The coated metal plate according to any one of (9) to (11), wherein the average particle size of the anatase titanium oxide is 5 to 200 nm.

[0026] (13) The coated metal sheet according to any one of (1) to (12), wherein the metal sheet is a galvanized steel sheet, a galvanized-aluminum alloy steel sheet, a galvanized-aluminum-magnesium alloy steel sheet, an aluminized steel sheet, a galvanized-nickel alloy steel sheet, a galvanized-iron alloy steel sheet, an aluminum sheet or a stainless steel sheet.

[0027] (14) A coated metal sheet according to any one of (1) to (13), wherein there are wires on the surface of the metal sheet along the rolling direction of the metal sheet.

[0028] (15) A coated metal sheet according to any one of (1) to (13), wherein a zinc flower pattern is present on the surface of the metal sheet.

[0029] The effects of the invention

[0030] As described above, according to the present invention, the photocatalytic effect can be further improved while suppressing costs. Attached Figure Description

[0031] Figure 1A An explanatory diagram illustrating an example of the structure of a coated metal sheet according to an embodiment of the present invention.

[0032] Figure 1B An illustrative diagram is provided to schematically show another example of the structure of a coated metal sheet according to the same embodiment.

[0033] Figure 1C An illustrative diagram is provided to schematically show another example of the structure of a coated metal sheet according to the same embodiment.

[0034] Figure 2A An illustrative diagram is provided to schematically show another example of the structure of a coated metal sheet according to the same embodiment.

[0035] Figure 2B An illustrative diagram is provided to schematically show another example of the structure of a coated metal sheet according to the same embodiment.

[0036] Figure 3 This is an explanatory diagram used to illustrate a coated metal sheet of the same embodiment. Detailed Implementation

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the drawings, constituent elements having substantially the same functional structure are omitted from repeated description by using the same reference numerals.

[0038] (Regarding coated metal sheets)

[0039] <Structure of Coated Metal Sheets>

[0040] Below, we will first refer to Figures 1A to 2B The structure of the coated metal sheet according to an embodiment of the present invention will be described below. Figure 1A An explanatory diagram illustrating an example of the structure of the coated metal sheet according to this embodiment. Figures 1B to 2B An explanatory diagram illustrating another example of the structure of the coated metal sheet of this embodiment.

[0041] like Figure 1A As schematically shown, the coated metal plate 1 of the embodiment of the present invention has a film layer on at least one side of the metal plate, and has at least a metal plate 10 as a base material and a photocatalyst layer 20 as a film layer, and as an example of a first film layer. Alternatively, a rigid resin substrate such as melamine resin could be used instead of a metal plate as the substrate. However, it is important to use a substrate capable of various processing methods; in this embodiment, a metal plate is used as the substrate.

[0042] [Regarding metal plate 10]

[0043] In the coated metal sheet 1 of this embodiment, various metal sheets can be used as the base material, namely the metal sheet 10. Examples of such metal sheets include galvanized steel sheet, galvanized aluminum alloy steel sheet, galvanized aluminum-magnesium alloy steel sheet, aluminized steel sheet, galvanized nickel alloy steel sheet, galvanized iron alloy steel sheet, aluminum sheet, and stainless steel sheet.

[0044] By using the aforementioned metal plate, light incident on the coated metal plate 1 (especially light in the ultraviolet to visible light band) can be efficiently reflected on the surface of the metal plate 10. Therefore, in the coated metal plate 1 of this embodiment, as described later, the reflected light from the surface of the metal plate 10 can be used for a photocatalytic reaction. Among the aforementioned metal plates, galvanized-aluminum-magnesium alloy steel plates, stainless steel plates, aluminized steel plates, galvanized steel plates, and galvanized-aluminum alloy steel plates are particularly preferred because they can efficiently reflect incident light. Furthermore, metal plates with designs such as brushed or zinc flower patterns on their electroplated surfaces can also be used as outer components, and are therefore preferred.

[0045] Here, there is no particular limitation on the thickness of the metal plate 10 as described above, as long as it is set appropriately according to the mechanical strength (e.g., tensile strength, etc.) and processability required by the coated metal plate 1 of this embodiment.

[0046] Furthermore, various patterns such as wire drawing patterns and zinc flower patterns along the rolling direction of the metal sheet 10 can also be present on the surface of the metal sheet 10 (when a metal sheet subjected to various electroplating processes is used as the metal sheet 10). By setting such patterns, the design flexibility of the coated metal sheet 1 can be further improved. In addition, the design and processing for setting such patterns on the surface of the metal sheet 10 also contributes to the further improvement of the 60° mirror gloss level, as described below.

[0047] For example, consider the metal sheet 10 that has undergone electroplating. Generally, when electroplating the surface of a metal substrate, electroplating or melt electroplating methods can be used. Depending on the electroplating method used, fine particles may sometimes be generated on the electroplated surface, resulting in a decrease in the gloss of the surface of the electroplated metal sheet 10 (i.e., the gloss of the electroplated surface). However, by performing a wire drawing process on such an electroplated surface, the electroplated surface is cut, resulting in an increase in the light reflectivity of the electroplated surface, thereby improving the surface gloss. In addition, electroplating in a manner that forms a zinc flower pattern results in the appearance of electroplated crystal orientations on the surface that make light more reflective, which can increase the light reflectivity of the electroplated surface and improve the surface gloss.

[0048] As detailed below, in the coated metal sheet 1, the thickness of the photocatalyst layer 20, which serves as the first film layer, and the total thickness from the surface of the metal sheet 10 in the coated metal sheet 1 to the outermost surface of the photocatalyst layer 20, which serves as the first film layer, are controlled in a specific manner. Based on this, by further implementing design processing, primarily using brushed patterns and zinc flower patterns as described above, this design processing also serves to further improve the 60° mirror gloss, as explained below. Regarding the method for forming such patterns, various known processing methods can be appropriately utilized.

[0049] [Regarding photocatalyst layer 20]

[0050] In the coated metal plate 1 of this embodiment, as Figure 1A As schematically shown, the photocatalyst layer 20, as an example of the first film layer, is a layer located on the outermost surface of the film layer on at least one side of the metal plate 10, and contains at least a photocatalyst-active compound (hereinafter sometimes simply referred to as "photocatalyst compound"). The photocatalyst layer 20 contains a photocatalyst-active compound, which undergoes a photocatalytic reaction due to light incident on the photocatalyst layer 20 (especially light in the ultraviolet-visible band). As a result, the photocatalyst layer 20 of this embodiment exhibits various photocatalytic effects, primarily antiviral and bactericidal effects. Therefore, the coated metal plate 1 of this embodiment can achieve various properties, primarily antiviral and bactericidal effects.

[0051] For such photocatalytically active compounds, there exist: compounds that exhibit photocatalytic activity primarily through photoreaction with the ultraviolet light band (more specifically, through photoexcitation with the ultraviolet light band); and compounds that exhibit photocatalytic activity primarily through photoreaction with the visible light band (more specifically, through photoexcitation with the visible light band).

[0052] Compounds exhibiting photocatalytic activity in response to ultraviolet light include, for example, titanium oxide (more specifically, anatase titanium oxide), zinc oxide, cerium oxide, tin oxide, bismuth oxide, zirconium oxide, tungsten oxide, 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, and other metal oxides; metal sulfides such as cadmium sulfide and zinc sulfide; and titanium compounds such as strontium titanate and barium titanate. Among these, anatase titanium oxide, zinc oxide, tin oxide, zirconium oxide, tungsten oxide, iron oxide, niobium oxide, and strontium titanate are particularly preferred as compounds exhibiting photocatalytic activity in response to ultraviolet light, with anatase titanium oxide being even more preferred.

[0053] Furthermore, compounds exhibiting photocatalytic activity through photoreaction with the visible light band include, for example, metal-supported titanium oxide (more specifically, anatase titanium oxide) supported on at least one metal in Cu and Fe, anatase titanium oxide supported on Cr, V, Mn, Ni, or Pt, anatase titanium oxide doped with anions such as nitrogen or sulfur, and solid solutions of AgNbO3 and SrTiO3. Among these, anatase titanium oxide supported on at least one metal in Cu and Fe is particularly preferred.

[0054] In this photocatalyst compound, the average particle size (primary particle size) of anatase titanium oxide (including those supported in a metal state) is preferably 5 nm or more. By making the average particle size (primary particle size) of anatase titanium oxide 5 nm or more, the anatase titanium oxide can be more uniformly dispersed in the photocatalyst layer 20. The average particle size (primary particle size) of anatase titanium oxide is more preferably 20 nm or more. In addition, the average particle size (primary particle size) of anatase titanium oxide (including those supported in a metal state) is preferably 200 nm or less. By making the average particle size (primary particle size) of anatase titanium oxide 200 nm or less, the excessive aggregation of anatase titanium oxide in the photocatalyst layer 20 can be suppressed while the anatase titanium oxide is more uniformly dispersed in the photocatalyst layer 20. The average particle size (primary particle size) of anatase titanium oxide is more preferably 100 nm or less.

[0055] Here, the average particle size of the aforementioned anatase titanium dioxide can be determined, for example, by using dynamic light scattering with a laser. This method can easily obtain highly accurate measurements. When the anatase titanium dioxide particles aggregate to a certain extent, it may be necessary to measure the size of the aggregates (aggregate particle size). Therefore, it is preferable to combine this with direct confirmation of the primary particle size using transmission electron microscopy (TEM). If the presence of aggregated particles is confirmed by TEM observation, it is preferable to change the dispersion conditions and measure again using dynamic light scattering. Furthermore, if it is difficult to completely disperse to the level of primary particles, the size of the primary particles observed / measured by TEM can also be used as the primary particle size. In such cases, the inventors' experience shows that by arbitrarily selecting approximately 100 or more particles as the measurement targets, a value representative of the entire particle structure can be obtained.

[0056] Furthermore, for the coated metal plate 1 on which the photocatalyst layer 20 has already been formed, when subsequently determining the average particle size of the anatase titanium oxide contained in the photocatalyst layer 20, the following procedure can be followed: That is, a transmission electron microscope (TEM) can be used to observe or analyze the cross-section of the photocatalyst layer 20 when cut along the thickness direction. Using TEM, the primary particle size of the photocatalyst compound can be determined. Additionally, by performing EDS analysis along with TEM, the elements contained in the photocatalyst compound can be determined. Furthermore, by electron beam diffraction, the crystal structure of the photocatalyst compound (e.g., whether it is anatase or rutile in the case of titanium oxide) can be determined. The inventors' experience shows that by arbitrarily selecting approximately 100 or more particles as the measurement targets, a value representative of the entire particle structure can be obtained.

[0057] Here, the concentration of anatase titanium dioxide (including those supported in a metal state) in the photocatalyst layer 20 is preferably 50% by mass or more, calculated as titanium dioxide. By making the concentration of anatase titanium dioxide in the photocatalyst layer 20 50% by mass or more, various photocatalytic effects, such as antiviral effects, can be reliably exhibited. The concentration of anatase titanium dioxide in the photocatalyst layer 20 is more preferably 60% by mass or more, calculated as titanium dioxide. Furthermore, the concentration of anatase titanium dioxide (including those supported in a metal state) in the photocatalyst layer 20 is preferably 95% by mass or less, calculated as titanium dioxide. By making the concentration of anatase titanium dioxide in the photocatalyst layer 20 95% by mass or less, various photocatalytic effects, such as antiviral effects, can be exhibited while suppressing the increase in manufacturing costs. The concentration of anatase titanium dioxide in the photocatalyst layer 20 is more preferably 80% by mass or less, calculated as titanium dioxide.

[0058] In addition, for photocatalyst compounds other than anatase titanium dioxide, the same applies as above, preferably having an average particle size of 5 to 200 nm and a concentration of 50 to 95% by mass.

[0059] In addition, as a photocatalyst compound represented by anatase titanium dioxide as described above, it is certainly possible to use particulate materials. Alternatively, depending on the need, materials such as sol-like materials that cannot be called particulates or metal complexes generated by heating can also be used.

[0060] Furthermore, the photocatalyst layer 20 also contains at least one element selected from Si and Zr, and the total concentration of this element is preferably 5% by mass or more for Si (converted to silica) and Zr (converted to zirconium oxide). In other words, the photocatalyst layer 20 is an inorganic film having an inorganic framework containing at least one element selected from Si and Zr, and which may contain impurities. The total concentration of at least one element selected from Si and Zr is preferably 5% by mass or more for Si (converted to silica) and Zr (converted to zirconium oxide). By containing at least one element selected from Si and Zr at the above concentration, a photocatalyst layer 20 with superior corrosion resistance can be achieved. The total content of at least one element selected from Si and Zr is more preferably 10% by mass or more. Additionally, the photocatalyst layer 20 contains at least one element selected from Si and Zr, and the total concentration of this element is preferably 50% by mass or less for Si (converted to silica) and Zr (converted to zirconium oxide). By containing at least one element from Si and Zr at the above-mentioned concentration, a photocatalyst layer 20 with superior corrosion resistance can be achieved. The total content of at least one element from Si and Zr is more preferably 40% by mass or less. Here, the Si or Zr contained is preferably an inorganic component with excellent light transmittance, and furthermore, it is preferably an inorganic component that is not easily affected by decomposition or other effects caused by the photocatalyst. Examples of such inorganic components containing Si and Zr include, for example, silicon dioxide and zirconium oxide.

[0061] In addition, the photocatalyst layer 20 containing the above-mentioned photocatalyst compound may also contain adsorbent materials such as antibacterial agents, activated carbon or zeolite, as needed, without impairing the effect of the present invention.

[0062] The average thickness d1 of the photocatalyst layer 20 (in) Figure 1A In the case of the layered structure shown, the total thickness d is also the thickness from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20 (which can also be regarded as the outermost surface of the film layer). T The average thickness d1 of the photocatalyst layer 20 is 0.05 μm or more. When the average thickness d1 of the photocatalyst layer 20 is less than 0.05 μm, it is difficult to uniformly form the photocatalyst layer 20 as described above, resulting in uneven photocatalytic effects, which is therefore undesirable. By setting the average thickness d1 to 0.05 μm or more, the desired photocatalytic effect can be uniformly exhibited throughout the entire photocatalyst layer 20. On the other hand, the average thickness d1 of this photocatalyst layer 20 (in...) Figure 1A In the case of the layered structure shown, the total thickness d from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20 is also considered. TThe average thickness d1 of the photocatalyst layer 20 is 5.00 μm or less. When the average thickness d1 of the photocatalyst layer 20 is greater than 5.00 μm, the photocatalytic effect becomes saturated, and the manufacturing cost increases, making this undesirable. Furthermore, since the photocatalyst layer is an inorganic film, its processability is reduced. By setting the average thickness d1 to 5.00 μm or less, the desired photocatalytic effect can be uniformly exhibited throughout the entire photocatalyst layer 20 while suppressing the increase in manufacturing cost and the reduction in processability.

[0063] Typically, light passes through the photocatalyst layer 20 with a certain probability without encountering the photocatalyst compound. This light, which does not interact with the photocatalyst compound, has historically resulted in no photocatalytic effect. In this embodiment, by reflecting such light onto the surface of the metal plate 10, the probability of light incident on the photocatalyst layer 20 colliding with the photocatalyst compound can be increased. Therefore, in this embodiment, the photocatalytic effect can be further improved. Figure 1A In the case of the layered structure shown, the total thickness d from the surface of the metal plate 10 to the outermost surface of the photocatalyst layer 20 is... T Of course, it is below 15.00 μm. As a result, the reflected light reflected by the incident light on the surface of the metal plate 10 (in other words, the interface between the metal plate 10 and the photocatalyst layer 20) can be used for the photocatalytic reaction caused by the photocatalyst compound, thus further improving the photocatalytic effect while suppressing costs.

[0064] The average thickness d1 of the photocatalyst layer 20 is preferably 0.10 μm or more, more preferably 0.15 μm or more. Furthermore, the average thickness d1 of the photocatalyst layer 20 is preferably 2.00 μm or less, more preferably 1.00 μm or less.

[0065] [60° Specular gloss]

[0066] In having Figure 1AIn the coated metal plate 1 with the layered structure shown, the 60° specular gloss obtained by measuring the coated metal plate 1 from the side where the photocatalyst layer 20 is provided, based on the light reflection caused by the metal plate 10 and the photocatalyst layer 20 having an average thickness d1 as described above, is 80% or more, as specified in JIS Z8741:1997. In other words, by achieving a 60° specular gloss of 80% or more as described above, the coated metal plate 1 of this embodiment can effectively utilize the reflected light generated at the interface between the metal plate 10 and the photocatalyst layer 20, exhibiting excellent antiviral performance. Furthermore, light colliding with the photocatalyst is not detected as reflected light, but in the film structure of the present invention, such light is a very small part of the overall amount. Therefore, even considering the reduction caused by the photocatalyst, excellent antiviral performance can be judged by satisfying the requirement of 80% or more for a 60° specular gloss of the present invention. In the coated metal plate 1 of this embodiment, a 60° specular gloss of 90% or more is preferred, and a 130% or more is more preferred. Furthermore, while there is no specific upper limit to the 60° specular gloss level, it is unlikely to exceed 200%, and this value is considered a de facto upper limit. Additionally, the 60° specular gloss level can be measured using a gloss meter conforming to the aforementioned JIS standard.

[0067] <Variation Example>

[0068] have Figure 1A The coated metal plate 1 of this embodiment, with the layered structure shown, can also have a further coating layer between the metal plate 10 and the photocatalyst layer 20, which functions as a chemical conversion treatment coating layer. By providing a chemical conversion treatment 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, the corrosion resistance of the coated metal plate 1 of this embodiment can also be further improved.

[0069] In the coated metal plate 1 of this embodiment, when a chemical conversion treatment film layer is further provided, it is preferable to achieve the two layer structures shown below based on the types of compound components constituting the chemical conversion treatment film layer. Hereinafter, with reference to... Figures 1B to 3 The layer structure of the coated metal sheet with a chemically converted coating layer is described in detail.

[0070] Figure 1B Figure 2 is an explanatory diagram schematically showing another example of the structure of the coated metal sheet of this embodiment. Figure 3 This is an explanatory diagram used to illustrate the coated metal sheet of this embodiment.

[0071] [Scenario of setting up inorganic chemical transformation treatment of the film layer]

[0072] Figure 1B and Figure 1C This is a schematic diagram illustrating the layer structure of the coated metal plate 1 when an inorganic chemical conversion treatment film layer composed of inorganic components is provided as the chemical conversion treatment film layer.

[0073] In this case, the coated metal plate 1 of this embodiment has an inorganic chemical conversion treatment film layer 30, which is an example of a second film layer, between the metal plate 10 as described above and the photocatalyst layer 20.

[0074] Photocatalyst compounds, such as anatase titanium dioxide, possess extremely excellent oxidizing properties. Therefore, when a film layer is placed on the layer below the layer containing the photocatalyst compound, a protective layer is often formed to protect this film layer. However, as will be explained below, by constructing a chemically converted film layer from inorganic components, a chemically converted film layer can be configured without a protective layer.

[0075] After removing oil and other impurities and surface oxides adhering to the surface of the metal plate 10 through known degreasing and cleaning processes, the inorganic chemical conversion treated film layer 30 is formed by chemical conversion treatment. The inorganic chemical conversion treated film layer 30 is preferably composed of an inorganic component having at least one of the elements Si and Zr. Alternatively, the inorganic chemical conversion treated film layer 30 may also contain an inorganic component having at least one of the elements P and V.

[0076] The inorganic chemical conversion treatment film layer 30 contains inorganic components with the aforementioned elements, thereby improving the film-forming properties after the chemical conversion treatment solution is applied, the barrier properties (density) of the film against corrosive factors such as moisture and corrosive ions, and the adhesion of the film to the metal plate surface, which helps to improve the corrosion resistance of the film.

[0077] Examples of inorganic components containing Si include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, and γ-(2-aminoethyl)aminopropyltriethoxysilane. Examples of inorganic components containing Zr include zirconium carbonate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium carbonate, and ammonium zirconium carbonate.

[0078] In addition, examples of inorganic components containing phosphorus (P) include phosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, and their salts, as well as ammonium dihydrogen phosphate. Examples of inorganic components containing vitamin (V) include ammonium metavanadate (V), potassium metavanadate (V), sodium metavanadate (V), and vanadium sulfate (IV).

[0079] In the inorganic chemical conversion treatment film layer 30 of this embodiment, various inorganic components as described above can be used alone or in combination. Furthermore, the content of these various inorganic components can be appropriately adjusted.

[0080] The average thickness d2 of the inorganic chemical conversion treated film layer 30 is preferably 0.10 μm or more, more preferably 0.20 μm or more. This allows the inorganic chemical conversion treated film layer 30 to be uniformly formed on the surface of the metal plate 10, while stably exhibiting the various effects produced by providing such a chemical conversion treated film layer. Furthermore, the average thickness d2 of the inorganic chemical conversion treated film layer 30 is preferably 5.00 μm or less, more preferably 1.00 μm or less. This allows the inorganic chemical conversion treated film layer 30 to be uniformly formed on the surface of the metal plate 10, while stably exhibiting the various effects produced by providing such a chemical conversion treated film layer.

[0081] Furthermore, the ratio (d2 / d1) of the average thickness d2 of the inorganic chemical conversion treated film layer 30 to the average thickness d1 of the photocatalyst layer 20 is preferably 0.3 or more, more preferably 0.5 or more. This further improves processing adhesion. Additionally, the ratio (d2 / d1) of the average thickness d2 of the inorganic chemical conversion treated film layer 30 to the average thickness d1 of the photocatalyst layer 20 is preferably 12.0 or less, more preferably 5.0 or less. This further improves processing adhesion.

[0082] In addition, such as Figure 1C As schematically shown, the coated metal plate 1 of this embodiment may also have various known layers, such as a coloring layer containing various coloring pigments, between the photocatalyst layer 20 and the inorganic chemical conversion treatment film layer 30.

[0083] Here, even in such Figure 1B and Figure 1C In the case shown, the total thickness d from the surface of the metal plate 10 to the outermost surface of the film layer (which is also the outermost surface of the photocatalyst layer 20) is... T (=d1+d2+α) is also below 15.00μm. Therefore, as... Figure 3 As schematically shown, the reflected light from the surface of the metal plate 10 (in other words, the interface between the metal plate 10 and the photocatalyst layer 20) can be used for the photocatalytic reaction induced by the photocatalyst compound, thus further improving the photocatalytic effect while suppressing the increase in cost. The total thickness d from the surface of the metal plate 10 to the outermost surface of the film layer... T (=d1+d2+α) is preferably 10.00μm or less, more preferably 7.00μm or less.

[0084] In addition, even in Figure 1B and Figure 1C In the case shown, the 60° specular gloss obtained by measuring the coated metal plate 1 from the side where the photocatalyst layer 20 is provided, according to JIS Z8741:1997, is also 80% or more. Here, if the total thickness d T If the gloss level is below 15.00 μm and the specular gloss level is above 80% at 60°, it can be considered that the reflected light from the incident light on the surface of the metal plate 10 is used for the photocatalytic reaction caused by the photocatalyst compound.

[0085] [Scenario of setting up an organic chemical transformation treatment for the film layer]

[0086] Figure 2A and Figure 2B This is a schematic diagram illustrating the layer structure of the coated metal plate 1 when an organic chemical conversion treatment film layer containing organic components is provided as the chemical conversion treatment film layer.

[0087] In this case, the coated metal plate 1 of this embodiment has an organic chemical conversion treatment film layer 40, which is an example of a third film layer, and a protective layer 50, which is an example of a fourth film layer, between the metal plate 10 as described above and the photocatalyst layer 20.

[0088] Organic Chemical Transformation Treatment of Coating Layer 40

[0089] The organic chemical conversion treatment film layer 40 is a layer located below the photocatalyst layer 20 (more specifically, on the surface of the metal plate 10), and is formed by chemical conversion treatment after removing impurities such as oil and surface oxides adhering to the surface of the metal plate 10 through known degreasing and cleaning processes.

[0090] The organic chemical conversion treatment film layer 40 of this embodiment may contain, for example, any one or more substances selected from the group consisting of resin, silane coupling agent, zirconium compound, silicon dioxide, phosphate and its salts, fluoride, vanadium compound, and tannin or tannic acid. By containing these substances, the film-forming properties after coating with the chemical conversion treatment solution, the barrier properties (density) of the film against corrosive agents such as moisture and corrosive ions, and the film's adhesion to the metal plate surface are further improved, which helps to improve the corrosion resistance of the film.

[0091] In particular, when the organic chemical conversion treated film layer 40 contains any one or more of silane coupling agents or zirconium compounds, a cross-linked structure is formed within the organic chemical conversion treated film layer 40, which also strengthens the bonding with the metal plate surface, thus further improving the film's adhesion and barrier properties.

[0092] In addition, when the organic chemical conversion treatment film layer 40 contains any one or more of silicon dioxide, phosphate and its salts, fluorides, or vanadium compounds, it acts as an inhibitor to form a precipitation film or passivation film on the metal plate surface, which can further improve corrosion resistance.

[0093] The following examples illustrate the details of the components that may be included in the organic chemical transformation treatment film layer 40 as described above.

[0094] [Resin]

[0095] As the resin, known organic resins such as polyester resin, polyurethane resin, epoxy resin, phenolic resin, acrylic resin, and polyolefin resin can be used. To further improve adhesion to the metal plate, it is preferable to use at least one resin (polyester resin, polyurethane resin, epoxy resin, acrylic resin, etc.) with forced sites and polar functional groups in its molecular chain. The resin can be used alone or in combination of two or more.

[0096] The resin content in the organic chemical conversion treated film layer 40 is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the film's solid content. This improves corrosion resistance. Furthermore, the resin content in the organic chemical conversion treated film layer 40 is preferably 85% by mass or less, more preferably 60% by mass or less, and even more preferably 40% by mass or less, relative to the film's solid content. By keeping the resin content at 85% by mass or less, the corrosion resistance of the film can be improved while ensuring the properties required for the film other than corrosion resistance.

[0097] [Silane coupling agent]

[0098] Examples of silane coupling agents include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, and N-β-(N-vinylbenzylamino) N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldiethoxysilane oxysilanes, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropylmethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropylmethyldiethoxysilane, vinyl Trimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldimethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(triethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldiethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, etc. The amount of silane coupling agent added to the chemical conversion treatment agent used to form the organic chemical conversion treatment film layer 40 can be, for example, 2 to 80 g / L. By adding silane coupling agent at a level of 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. In addition, by keeping the amount of silane coupling agent added below 80 g / L, the cohesiveness of the chemically converted film can be maintained and the processing adhesion of the coating film can be improved.The silane coupling agents listed above can be used in one or in combination of two or more.

[0099] [Zirconium compounds]

[0100] Examples of zirconium compounds include zirconium n-propyl ester, zirconium n-butoxide, zirconium tetraacetylacetone, zirconium monoacetylacetone, zirconium diacetylacetone, zirconium monoethylacetoacetate, zirconium diethylacetoacetate, zirconium acetate, zirconium monostearate, zirconium carbonate, ammonium zirconium carbonate, potassium zirconium carbonate, and sodium zirconium carbonate. The amount of zirconium compound added to the chemical conversion agent used to form the organic chemical conversion treatment film layer 40 can be, for example, 2 to 80 g / L. By adding 2 g / L or more of the zirconium compound, the adhesion to the metal plate surface can be improved, and the processing adhesion of the coating film can be enhanced. Furthermore, by adding 80 g / L or less of the zirconium compound, the cohesiveness of the chemical conversion treatment film can be maintained, and the processing adhesion of the coating film can be improved. This zirconium compound can be used alone or in combination of two or more.

[0101] [Silicon dioxide]

[0102] Examples of silica include commercially available silicone rubbers such as "SNOWTEX N", "SNOWTEX C", "SNOWTEX UP", and "SNOWTEX PS" manufactured by Nissan Chemical Co., Ltd., "Adelite AT-20Q" manufactured by ADEKA Co., Ltd., and powdered silica such as AEROSIL #300 manufactured by AEROSIL Co., Ltd. The silica can be appropriately selected based on the desired properties of the metal sheet to be coated. The amount of silica added to the chemical conversion agent used to form the organic chemical conversion treatment film layer 40 is preferably 1 to 40 g / L. By adding 1 g / L or more of silica, the processing adhesion of the coating film can be improved. Furthermore, by adding 40 g / L or less of silica, a balance between processing adhesion and corrosion resistance can be achieved while suppressing cost increases.

[0103] [Phosphate and its salts]

[0104] Examples of phosphoric acid and its salts include, for example, phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid, and their salts; ammonium salts such as triammonium phosphate and diammonium hydrogen phosphate; phosphonic acids such as aminotris(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), and diethylenetriaminepenta(methylenephosphonic acid), and their salts; and organophosphoric acids such as phytic acid and their salts. Additionally, as salts of phosphoric acid, salts other than ammonium salts can be included, such as those containing metal salts of Na, Mg, Al, K, Ca, Mn, Ni, Zn, and Fe. Phosphoric acid and its salts can be used alone or in combination of two or more.

[0105] Furthermore, the content of phosphoric acid and its salts is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the coating. Additionally, the content of phosphoric acid and its salts is preferably 20% by mass or less, more preferably 10% by mass or less, relative to the solid content of the coating. By keeping the content of phosphoric acid and its salts at 20% by mass or less, embrittlement of the coating can be prevented, and a decrease in the processing adhesion of the coating during the forming process of the coated metal sheet can be prevented.

[0106] [Fluorides]

[0107] Examples of fluorides include ammonium zirconium fluoride, ammonium silicofluoride, ammonium titanium fluoride, sodium fluoride, potassium fluoride, calcium fluoride, lithium fluoride, hydrogen fluoride titanium, and hydrogen fluoride zirconium. These fluorides can be used alone or in combination of two or more.

[0108] Furthermore, the fluoride content is preferably 0% by mass or more, more preferably 1% by mass or more, relative to the solid content of the coating. Additionally, the fluoride content is preferably 20% by mass or less, more preferably 10% by mass or less, relative to the solid content of the coating. By keeping the fluoride content at 20% by mass or less, embrittlement of the coating can be prevented, and a decrease in the processing adhesion of the coating during the forming process of the coated metal sheet can be prevented.

[0109] [vanadium compounds]

[0110] Examples of vanadium compounds include those obtained by reducing pentavalent vanadium compounds such as vanadium pentoxide, metavanadate, ammonium metavanadate, sodium metavanadate, and vanadium oxychloride to vanadium compounds with oxidation states of 2 to 4 with a reducing agent; and vanadium compounds with oxidation states of 4 to 2 such as vanadium trioxide, vanadium dioxide, vanadium oxysulfate, vanadium oxyoxalate, vanadium oxyacetylacetonate, vanadium acetylacetonate, vanadium trichloride, vanadium phosphomolybdic acid, vanadium sulfate, vanadium dichloride, and vanadium oxide. These vanadium compounds can be used alone or in combination of two or more.

[0111] Furthermore, the content of vanadium compounds relative to the solid composition of the coating is preferably 0% by mass or more, more preferably 1% by mass or more. Additionally, the content of vanadium compounds relative to the solid composition of the coating is preferably 20% by mass or less, more preferably 10% by mass or less. By keeping the content of vanadium compounds at 20% by mass or less, embrittlement of the coating can be prevented, and a decrease in the processing adhesion of the coating during the forming process of the coated metal sheet can be prevented.

[0112] [Tannins or tannic acid]

[0113] Any one of hydrolyzable tannins or condensed tannins can be used as tannin or tannic acid. Examples of tannins and tannic acids include witch hazel tannin, gallnut tannin, gallic acid tannin, myrobalan tannin, divi-divi tannin, algarovilla tannin, Valonia tannin, catechin, etc. The amount of tannin or tannic acid added to the chemical conversion agent used to form the organic chemical conversion treatment film layer 40 can be 2 to 80 g / L. By adding tannin or tannic acid at a level of 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. In addition, by adding tannin or tannic acid at a level of 80 g / L or less, the cohesiveness of the chemical conversion treatment film can be maintained, and the processing adhesion of the coating film can be improved.

[0114] In addition, in the chemical conversion treatment agent used to form the organic chemical conversion treatment film layer 40, acids, bases, etc. may be added to adjust the pH within a range that does not impair performance.

[0115] The average thickness d3 of the organic chemical conversion treated film 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. This allows the organic chemical conversion treated film layer 40 to be uniformly formed on the surface of the metal plate 10, while stably exhibiting the various effects produced by providing such a chemical conversion treated film layer. Furthermore, the average thickness d3 of the organic chemical conversion treated film 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. This allows the organic chemical conversion treated film layer 40 to be uniformly formed on the surface of the metal plate 10, while stably exhibiting the various effects produced by providing such a chemical conversion treated film layer.

[0116] Furthermore, the ratio (d3 / d1) of the average thickness d3 of the organic chemical conversion treated film layer 40 to the average thickness d1 of the photocatalyst layer 20 is preferably 0.5 or more, more preferably 2.0 or more. This further improves the adhesion of the processed section. Additionally, the ratio (d3 / d1) of the average thickness d3 of the organic chemical conversion treated film layer 40 to the average thickness d1 of the photocatalyst layer 20 is preferably 20.0 or less, more preferably 10.0 or less. This further improves the adhesion of the processed section.

[0117] Protective Layer 50

[0118] The protective layer 50 is a layer disposed between the photocatalyst layer 20 and the organic chemical conversion treatment film layer 40 (more preferably directly below the photocatalyst layer 20), and is provided to protect the layer located below the photocatalyst layer 20 from the oxidizing power of the photocatalyst compound contained in the photocatalyst layer 20.

[0119] Regarding the specific composition of the protective layer 50, it may contain various known components. Examples of such components include inorganic oxides such as silicon dioxide and zirconium oxide. Furthermore, the specific content of this component can be appropriately adjusted.

[0120] Furthermore, the protective layer 50 is preferably a protective layer with excellent light transmittance, similar to the photocatalyst layer 20. To achieve the excellent light transmittance of the protective layer 50, for example, the same components as those in the photocatalyst layer 20 other than the photocatalyst compound can be used.

[0121] The average thickness d4 of the protective layer 50 is preferably 0.05 μm or more, more preferably 0.20 μm or more. This allows for reliable protection of the layer located below the protective layer 50 from the oxidizing forces of the photocatalyst compound while suppressing a decrease in processability. Furthermore, the average thickness d4 of the protective layer 50 is preferably 5.00 μm or less, more preferably 0.60 μm or less. This allows for reliable protection of the layer located below the protective layer 50 from the oxidizing forces of the photocatalyst compound while suppressing a decrease in processability.

[0122] Furthermore, the ratio (d4 / d1) of the average thickness d4 of the protective layer 50 to the average thickness d1 of the photocatalyst layer 20 is preferably 0.3 or more, more preferably 1.0 or more. This reliably suppresses the decomposition of the organic chemical conversion treatment film layer 40 caused by the photocatalyst layer 20. Additionally, the ratio (d4 / d1) of the average thickness d4 of the protective layer 50 to the average thickness d1 of the photocatalyst layer 20 is preferably 20.0 or less, more preferably 3.0 or less. This reliably suppresses the decomposition of the organic chemical conversion treatment film layer 40 caused by the photocatalyst layer 20.

[0123] In addition, such as Figure 2B As schematically shown, the coated metal plate 1 of this embodiment may further have various known layers, such as a coloring layer containing various coloring pigments, between the photocatalyst layer 20 and the protective layer 50 and the organic chemical conversion treatment film layer 40.

[0124] Here, even in such Figure 2A and Figure 2B In the case shown, the total thickness d from the surface of the metal plate 10 to the outermost surface of the film layer (which is also the outermost surface of the photocatalyst layer 20) is...T (=d1+d3+d4+α) is also set to below 15.00μm. Therefore, as... Figure 3 As schematically shown, the reflected light from the surface of the metal plate 10 (in other words, the interface between the metal plate 10 and the photocatalyst layer 20) can be used for the photocatalytic reaction induced by the photocatalyst compound, thus further improving the photocatalytic effect while suppressing costs. The total thickness d from the surface of the metal plate 10 to the outermost surface of the film layer... T (=d1+d3+d4+α) is preferably 10.00 μm or less, more preferably 7.00 μm or less.

[0125] In addition, even in Figure 2A and Figure 2B In the case shown, the specular gloss at 60°, measured from the side where the photocatalyst layer 20 is provided, according to JIS Z8741:1997, is also 80% or higher. Here, if the total thickness d... T If the gloss level is below 15.00 μm and the specular gloss level is above 80% at 60°, it can be considered that the reflected light from the incident light reflected on the surface of the metal plate 10 is used for the photocatalytic reaction caused by the photocatalyst compound.

[0126] in addition, Figures 1A to 3 The diagram illustrates a case where layers, starting with photocatalyst layer 20, are disposed on one side of the metal plate 10. However, layers, starting with photocatalyst layer 20, can also be disposed on both sides of the metal plate 10. In this case, the total thickness d from the surface of the metal plate 10 to the surface of the photocatalyst layer 20 is... T The thickness is 15.00 μm or less on each surface of the coated metal plate 1. Furthermore, the 60° mirror gloss level is 80% or more on each surface of the coated metal plate 1. Additionally, when the inorganic chemical conversion treatment film layer 30 described above is applied, a protective layer 50 as described above can also be formed.

[0127] The above is for reference only. Figures 1A to 3 The coated metal sheet of this embodiment has been described in detail.

[0128] <Methods for determining the average thickness of each layer>

[0129] Here, the average thickness of each layer, starting with the photocatalyst layer, can be determined by observing the layer of interest under a microscope in a cross-sectional direction. Methods for preparing the sample for cross-sectional observation include, for example, known methods such as embedding the sample in resin to grind the observation surface, performing FIB processing, and slicing. Furthermore, regarding the type of microscope, known devices such as SEM and TEM can be used.

[0130] (Regarding the manufacturing method of coated metal sheets)

[0131] The coated metal of this embodiment, as described above, is manufactured by applying a photocatalytic treatment agent for forming a photocatalytic layer, a chemical conversion treatment agent for forming a chemical conversion treatment film layer, and a protective treatment agent for forming a protective layer in a manner that forms a desired layer structure, after performing various pretreatments such as cleaning on the surface of the metal plate that serves as the base material as required. It can then be manufactured by drying and sintering.

[0132] Here, the application of various coatings can generally be carried out by known coating methods such as roller coating, curtain coating, air spraying, airless spraying, dipping, bar coating, and brush coating. Roller coating, which can stably coat films with the characteristics of this product, is particularly preferred.

[0133] In addition, there are no particular restrictions on the drying and sintering conditions, which can be set appropriately according to the coatings used.

[0134] Example

[0135] Hereinafter, the coated metal sheet of the present invention will be specifically described with reference to embodiments and comparative examples. Furthermore, the embodiments shown below are merely examples of the coated metal sheet of the present invention, and the coated metal sheet of the present invention is not limited to the examples described below.

[0136] Eight types of metal sheets, as shown in Table 1 below, were prepared as the base materials. Additionally, six metal sheets labeled SD, ZL, GI, GL, AL, and GA in Table 1 are various electroplated steel sheets with steel sheets as the base material. The sheet thickness of each metal sheet, as well as the electroplating composition and adhesion amount / standard of each electroplated steel sheet, are shown in Table 1 below.

[0137] [Table 1]

[0138]

[0139] Seven compounds, listed in Table 2 below, were prepared as photocatalytically active compounds (photocatalyst compounds). All photocatalyst compounds were commercially available products. Table 2 also lists the supporting metal and average particle size.

[0140] [Table 2]

[0141]

[0142] <Inorganic / Organic Chemical Conversion Treatment Agents>

[0143] The raw materials and concentrations in the aqueous coatings (chemical conversion agents) used to form the inorganic and organic chemical conversion films are shown in Table 3 below. The addition amounts were adjusted to achieve predetermined concentrations in the dried films. Ion-exchanged water was added to adjust the concentration of the solid components of the treatment agent to 10% by mass in the inorganic chemical conversion film and 20% by mass in the organic chemical conversion film. Each treatment agent was applied to achieve the dry film thicknesses shown in Tables 4-1 and 4-2 below. The metal sheet was then dried in an induction furnace to a temperature of 150°C, followed by water cooling via spraying.

[0144] [Table 3]

[0145]

[0146] <Photocatalysts, Protective Agents>

[0147] The preparation methods of the photocatalytic treatment agent and the protective treatment agent used are explained.

[0148] Considering storage stability, the protective treatment agent was adjusted to a solid content concentration of 8% by mass. The concentration was adjusted by dilution with n-butanol. The photocatalytic treatment agent was prepared by adding predetermined amounts of the compounds shown in Table 2 to the protective treatment agent described below. The solid content concentrations of the photocatalyst compounds are shown in Tables 4-1 and 4-2 below.

[0149] (1) Protective film treatment agent (Si-based): Tetraethoxysilane (22.5 parts by mass), methacryloxypropyltrimethoxysilane (2.8 parts by mass), and n-butanol (26 parts by mass) were mixed and stirred at 60°C for 2 hours. While stirring the mixture, a mixture of 26% hydrochloric acid (3 parts by mass) and n-butanol (26 parts by mass) was added dropwise at 1 drop / second. The mixture was then kept at 60°C for 2 hours with stirring to obtain the treatment agent. All operations were carried out under a nitrogen atmosphere.

[0150] (2) Protective film treatment agent (Zr-based): 34.5 parts by mass of zirconium butoxyfluoride, 11.6 parts by mass of n-butanol, 0.5 parts by mass of 1,5-diaminopentane, and 2.8 parts by mass of yttrium nitrate were mixed and stirred for 1 hour. Then, 4.8 parts by mass of glacial acetic acid were added and stirred for 40 hours. Finally, 0.6 parts by mass of concentrated nitric acid were added dropwise at a rate of 1 drop / second and stirred for 2 hours to obtain the treatment agent. All these operations were carried out under a nitrogen atmosphere.

[0151] Using the metal sheet and photocatalyst compound shown above, coated metal sheets with the structures shown in Tables 4-1 and 4-2 are manufactured by roll coating. Each layer is formed on one side of the metal sheet. Furthermore, for some of the coated metal sheets, a designed processing is performed on the surface of the metal sheet to form a brushed pattern. Additionally, for some of the coated metal sheets, an electroplated steel sheet with a zinc flower pattern is used as the substrate by using a molten zinc plating bath containing 0.1% by mass of Sb and 0.2% by mass of Al, and adjusting the solidification rate of the molten zinc plating.

[0152] Furthermore, the average film thickness of each layer in the aforementioned coated metal sheet was measured as follows: the observation surface obtained by embedding the coated metal sheet into the resin and grinding the cross-section was observed under a microscope, and the measurement was performed accordingly. Additionally, the 60° specular gloss was measured using a gloss meter conforming to JIS Z8741:1997 (UGV-6P manufactured by Suga Testing Machine Co., Ltd.).

[0153] The coated metal sheets were evaluated from the perspectives of antiviral properties, processability, and corrosion resistance. Detailed evaluation methods are described below.

[0154] <Antiviral properties>

[0155] Regarding antiviral properties, the viral infection value was determined according to the antiviral standards specified by the Antimicrobial Products Technical Association, and verified by the following antiviral test. More specifically, each coated metal plate was placed face up in a petri dish, and a viral suspension containing influenza A virus was added dropwise to the evaluation surface. Then, a thin film was placed over the coated metal plate, ensuring the viral suspension adhered tightly to the entire evaluation surface, and the petri dish was then capped. The petri dish was left to stand for 24 hours in a simulated office environment at 25°C and 1000 lux of illumination. Afterward, the virus on the film surface and the evaluation surface was washed away, and the viral infection value (unit: PFU / cm³) in the resulting washing solution was determined using a plaque assay. 2 The determination was performed using PFU (Plaque Forming Units).

[0156] Independent of the coated metal panels, antiviral tests were also conducted on each metal panel without a photocatalyst layer. The virus infection value was compared with that of the metal panels without a photocatalyst layer, and the reduction in virus infection value of the coated metal panels was used as the activity value. If the virus infection value decreased by 10... 2 The above (in other words, if the activity value is 1×10) 2 (Above), given that the use of the certified seal as stipulated by the Antimicrobial Products Technical Association is permitted, the obtained activity value is 1×10 2Those above are judged as qualified. In addition, the values of the activity values obtained in logarithmic form are shown in Table 5 below.

[0157] <Processing tightness>

[0158] Perform 0T bending (180° bending) processing on the sample material. After peeling off the coating film on the outer side of the bent part with an adhesive tape (transparent tape (registered trademark) with a tape width of 15 mm manufactured by Nichiban Co., Ltd.), observe the situation where the coating film adheres to the tape side. And evaluate the processing tightness according to the following evaluation criteria. In this tightness test, the qualified level is set to 3 or more. Specifically, when the score is 4 or more, it is judged that the tightness is excellent, and when it is 3 or more, it is judged as allowable (qualified level).

[0159] (Evaluation criteria)

[0160] 5: No coating film adheres to the tape side

[0161] 4: When there are several states of coating film peeling on the tape side, the peeling length on the steel plate side is less than 5% of the total length of the processed part on one side of the sample material

[0162] 3: When there are several states of coating film peeling on the tape side, the peeling length on the steel plate side is 5% or more and less than 10% of the total length of the processed part on one side of the sample material

[0163] 2: There is coating film peeling on the tape side, and the peeling 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 sample material

[0164] 1: There is coating film peeling on the tape side, and the peeling length on the steel plate side is 20% or more of the total length of the processed part on one side of the sample material

[0165] <Corrosion resistance>

[0166] Seal the end face of the sample material with a tape and conduct a salt spray test (SST) conforming to JIS Z 2371 for 72 hours. And observe the rusting condition of the flat part after the test, and evaluate the corrosion resistance according to the following evaluation criteria. The qualified level is set to 3 or more.

[0167] (Evaluation criteria)

[0168] The area of white rust formation is less than 1% of the total area of one side of the sample material

[0169] 4: The area of white rust formation is 1% or more and less than 5% of the total area of one side of the sample material

[0170] 3: The area of white rust formation is 5% or more and less than 10% of the total area of one side of the sample material

[0171] 2: The area where white rust forms is more than 10% but less than 30% of the total area of ​​a single side of the sample material.

[0172] 1. The area of ​​white rust formation is more than 30% of the total area of ​​a single side of the sample material.

[0173] [Table 4-1]

[0174]

[0175] [Table 4-2]

[0176]

[0177] The results are summarized in Table 5 below.

[0178] As can be clearly seen from Table 5 below, the coated metal sheet conforming to the embodiments of the present invention exhibits excellent antiviral properties, processing adhesion and corrosion resistance. On the other hand, the evaluation results of the antiviral properties or processing adhesion of the coated metal sheet conforming to the comparative examples of the present invention are unsatisfactory.

[0179] [Table 5]

[0180]

[0181] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the examples described. Obviously, those skilled in the art to which this invention pertains can conceive of various modifications or variations within the scope of the technical concept described in the claims, and these examples are also within the protection scope of this invention.

[0182] Explanation of reference numerals in the attached figures

[0183] 1: Coated metal sheet

[0184] 10: Metal plate

[0185] 20: Photocatalyst layer (first film layer)

[0186] 30: Inorganic chemical transformation treatment of the film layer (second film layer)

[0187] 40: Organic chemical transformation treatment of the film layer (3rd film layer)

[0188] 50: Protective layer (4th membrane layer).

Claims

1. A coated metal sheet having a film layer on at least one side of the metal sheet, As the coating layer, the metal plate has a first coating layer located on the outermost surface of the coating layer and containing at least a compound with photocatalytic activity, and a second coating layer located below the first coating layer and composed of an inorganic system having at least one of Si and Zr. The average thickness of the first membrane layer is 0.05–5.00 μm. The average thickness of the second membrane layer is 0.10–5.00 μm. The total thickness from the surface of the metal plate to the outermost surface of the film layer is less than 15.00 μm. The second membrane layer also contains an inorganic component having at least one of the elements P and V. The coated metal sheet shall have a 60° specular gloss level of 80% or higher, as specified in JIS Z8741:1997. The photocatalytically active compound is one that exhibits photocatalytic activity through a photoreaction with the ultraviolet light band, or one that exhibits photocatalytic activity through a photoreaction with the visible light band. in, The compounds that exhibit photocatalytic activity in response to ultraviolet light are selected from the group consisting of titanium oxide, zinc oxide, cerium oxide, tin oxide, bismuth oxide, zirconium oxide, tungsten oxide, 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, cadmium sulfide, zinc sulfide, strontium titanate, and barium titanate. The compound exhibiting photocatalytic activity in response to light in the visible light band is selected from the group consisting of metal-supported titanium oxide supported on at least one metal in Cu and Fe, anatase titanium oxide supported on Cr, V, Mn, Ni, or Pt, anatase titanium oxide doped with nitrogen or sulfur, and solid solutions of AgNbO3 and SrTiO3.

2. The coated metal sheet according to claim 1, wherein, The first film layer also contains at least one element selected from Si and Zr. The total concentration of the elements is 5 to 50 by mass for Si (converted to silicon dioxide) and Zr (converted to zirconium oxide).

3. The coated metal sheet according to claim 1 or 2, wherein, The ratio of the average thickness of the second membrane layer to the average thickness of the first membrane layer is 0.3 to 12.

0.

4. The coated metal sheet according to any one of claims 1 to 3, wherein, The second film layer contains at least one of zirconium carbonate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium carbonate, or ammonium zirconium carbonate as the inorganic component containing Zr.

5. The coated metal sheet according to any one of claims 1 to 4, wherein, The second membrane layer contains at least one of phosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid and their salts, or ammonium dihydrogen phosphate as the inorganic component containing P.

6. The coated metal sheet according to any one of claims 1 to 5, wherein, The second membrane layer contains at least one of ammonium metavanadate (V), potassium metavanadate (V), sodium metavanadate (V), or vanadium sulfate (IV) as the inorganic component containing V.

7. The coated metal sheet according to any one of claims 1 to 6, wherein, The total thickness from the surface of the metal plate to the outermost surface of the first film layer is less than 10.00 μm.

8. The coated metal sheet according to any one of claims 1 to 7, wherein, The photocatalytically active compound is anatase titanium oxide.

9. The coated metal sheet according to claim 8, wherein, The anatase titanium oxide is a metal-supported titanium oxide supported on at least one of Cu and Fe.

10. The coated metal sheet according to claim 8 or 9, wherein, The concentration of the anatase titanium dioxide in the first film layer is 50-95% by mass, converted from titanium dioxide.

11. The coated metal sheet according to any one of claims 8 to 10, wherein, The average particle size of the anatase titanium oxide is 5–200 nm.

12. The coated metal sheet according to any one of claims 1 to 11, wherein, The metal plate is a galvanized steel plate, a galvanized aluminum alloy steel plate, a galvanized aluminum-magnesium alloy steel plate, an aluminized steel plate, a galvanized nickel alloy steel plate, a galvanized iron alloy steel plate, an aluminum plate, or a stainless steel plate.

13. The coated metal sheet according to any one of claims 1 to 12, wherein, The surface of the metal plate has wires drawn along the rolling direction of the metal plate.

14. The coated metal sheet according to any one of claims 1 to 12, wherein, A zinc flower pattern exists on the surface of the metal plate.

Images