Pre-coated metal board, member, and surface-treated metal board

Abstract

To further improve a coating film adhesion property during drawing while maintaining a corrosion resistance.SOLUTION: There is provided a pre-coated metal board, comprising: a metal board as a substrate; a coating layer disposed on at least one surface of the metal board; and an upper coating layer disposed on the coating layer, wherein the coating layer contains a resin, a Zr compound, and a Si compound, and has an average thickness of 0.5 to 15.0 μm; the upper coating layer has an average thickness of 5.0 to 30.0 μm; and when a hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer by using a nano-indenter, there is a portion where the nano-indenter hardness is 0.36 GPa or greater.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a precoated metal sheet, a member, and a surface-treated metal sheet. [Background technology]

[0002] Painted metal sheets, which are metal sheets that have been previously coated with various types of paint, are generally produced by applying various types of paint to the surface of various types of metal sheets, including plated steel sheets. Paints used for painted metal sheets are broadly divided into two types: solvent-based paints and water-based paints, and solvent-based paints have traditionally been widely used. When water-based paints are used, carbon dioxide emissions resulting from the procurement of solvents and the combustion of the solvents can be reduced. Therefore, switching from water-based paints to water-based paints is particularly desirable from the perspective of carbon neutrality, which has been attracting attention in recent years.

[0003] However, it is known that when the paint used is changed to a water-based paint, the adhesion of the formed paint film decreases. Therefore, various proposals have been made to prevent the decrease in adhesion of paint films made using water-based paint. For example, Patent Document 1 below examines the paint film adhesion of a coated metal sheet when a water-based paint is used as a primer paint, and Patent Document 2 below examines the paint film adhesion during drawing on a coated steel sheet when a water-based paint is used as a primer paint. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-107586 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-297648 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even when a coated steel sheet having a coating film as disclosed in Patent Document 2 is used, there is still room for improvement in the adhesion of the coating film during drawing, and there has been a demand for a technology that can further improve the adhesion of the coating film during drawing while maintaining corrosion resistance.

[0006] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a precoated metal sheet and a surface-treated metal sheet that can further improve paint film adhesion during drawing while maintaining corrosion resistance, and a component using such a precoated metal sheet. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present inventors first investigated the mechanism by which paint adhesion is reduced during drawing. As a result, they found that when a painted metal sheet having a paint film derived from a water-based paint is drawn, the paint film derived from the water-based paint follows the drawing process to some extent. This led the present inventors to discover that, as a result of the above-mentioned phenomenon, the paint film is unable to release residual stress associated with the drawing process, resulting in a decrease in paint adhesion. Based on this discovery, the present inventors conducted further research and came up with the idea of ​​a paint film configuration that can release residual stress associated with drawing, leading to the completion of the present invention, as described below. The gist of the present invention, which was completed based on these findings, is as follows.

[0008] (1) A precoated metal sheet comprising a metal plate as a substrate, a coating layer located on at least one surface of the metal plate, and an upper coating layer located on the coating layer, wherein the coating layer contains a resin, a Zr compound, and a Si compound, the coating layer has an average thickness of 0.5 to 15.0 μm, the upper coating layer has an average thickness of 5.0 to 30.0 μm, and when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more. (2) The precoated metal sheet according to (1), wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass % in terms of Zr. (3) A precoated metal sheet according to (2), wherein the content of the Zr compound in the coating layer is 3.0 mass% or more in terms of Zr, and the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H IT·B <H IT·A ...Equation (1) 1.1 ≦ H IT·A / H IT·B < 2.0...Equation (2) Here, in the above formulas (1) and (2), H IT·A : Average nanoindenter hardness of the phase A H IT·B : Average nanoindenter hardness of the phase B is. (4) A precoated metal sheet according to (3), wherein the content of the Zr compound in the coating layer is 3.0 mass% or more in terms of Zr, the phase A and the phase B in the coating layer satisfy the following formulas (3) and (4), and when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Zr·A / N Zr·B ≦ 6.0...Equation (3) 1.5 ≦ N Si·A / N Si·B ≦ 10.0...Equation (4) Here, in the above formulas (3) and (4), N Zr·A : Average Zr concentration (mass%) of the phase A N Zr·B : Average Zr concentration of the phase B (mass%) N Si·A : Average Si concentration (mass%) of the phase A N Si·B : Average Si concentration of the phase B (mass%) is. (5) The precoated metal sheet according to (1), wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.00. (6) The precoated metal sheet according to (1), wherein the resin is at least one of a urethane resin, a polyester resin, and an acrylic resin. (7) The precoated metal sheet according to (1), further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer. (8) The precoated metal sheet according to (1), wherein the coating layer further contains particles containing at least one element selected from Si, V, P, Mg, Ca, and Cr, and O, and having an average particle size of 0.5 to 7.0 μm, and the content of the particles is 2.0 mass% or less in terms of Si, V, P, Mg, Ca, or Cr. (9) The precoated metal sheet according to (1), wherein the hardness of the coating layer is measured by pressing an indenter into the cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. (10) The precoated metal sheet according to (1), wherein the metal sheet is a Zn-plated steel sheet having a Zn-plated layer on at least one surface of the steel sheet. (11) The precoated metal sheet according to (10), wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg. (12) A member having a predetermined shape, the member comprising a metal plate as a substrate, a coating layer located on at least one surface of the metal plate and containing a resin, a Zr compound, and a Si compound, and an upper coating layer located on the coating layer, wherein, in a 1 cm x 1 cm area of ​​the member, the coating layer has an average thickness of 0.5 to 15.0 μm, the upper coating layer has an average thickness of 5.0 to 30.0 μm, and when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more. (13) A surface-treated metal sheet comprising a metal sheet as a substrate and a coating layer located on at least one surface of the metal sheet, the coating layer containing a resin, a Zr compound, and a Si compound, the coating layer having an average thickness of 0.5 to 15.0 μm, and the coating layer having a nanoindenter hardness of 0.36 GPa or more when measured by pressing an indenter into a cross section of the coating layer with a nanoindenter. (14) The surface-treated metal sheet according to (13), wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass % in terms of Zr. (15) A surface-treated metal sheet according to (14), wherein the content of the Zr compound in the coating layer is 3.0 mass% or more in terms of Zr, and the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H IT·B <H IT·A ...Equation (1) 1.1 ≦ H IT·A / H IT·B < 2.0...Equation (2) Here, in the above formulas (1) and (2), H IT·A : Average nanoindenter hardness of the phase A H IT·B : Average nanoindenter hardness of the phase B is. (16) The surface-treated metal sheet according to (15), wherein the content of the Zr compound in the coating layer is 3.0 mass% or more in terms of Zr, the phase A and the phase B in the coating layer satisfy the following formulas (3) and (4), and when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Zr·A / N Zr·B ≦ 6.0...Equation (3) 1.5 ≦ N Si·A / N Si·B ≦ 10.0...Equation (4) Here, in the above formulas (3) and (4), N Zr·A : Average Zr concentration (mass%) of the phase A N Zr·B : Average Zr concentration of the phase B (mass%) N Si·A : Average Si concentration (mass%) of the phase A N Si·B : Average Si concentration of the phase B (mass%) is. (17) The surface-treated metal sheet according to (16), wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.00. (18) The surface-treated metal sheet according to (13), wherein the resin is at least one of a urethane-based resin, a polyester-based resin, and an acrylic-based resin. (19) The surface-treated metal sheet according to (13), further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer. (20) The surface-treated metal sheet according to (13), wherein the coating layer further contains particles containing at least one element selected from Si, V, P, Mg, Ca, and Cr, and O, and having an average particle size of 0.5 to 7.0 μm, and the content of the particles is 2.0 mass% or less in terms of Si, V, P, Mg, Ca, or Cr. (21) The surface-treated metal sheet according to (13), wherein the hardness of the coating layer is measured by pressing an indenter into the cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. (22) The surface-treated metal sheet according to (13), wherein the metal sheet is a Zn-plated steel sheet having a Zn-plated layer on at least one surface of the steel sheet. (23) The surface-treated metal sheet according to (22), wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg. [Effects of the Invention]

[0009] As described above, the present invention can provide precoated metal sheets and surface-treated metal sheets that can further improve paint film adhesion during drawing while maintaining corrosion resistance, as well as components using such precoated metal sheets. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a precoated metal sheet according to an embodiment of the present invention. [Figure 2] 2 is a schematic diagram showing an example of the configuration of a coating layer of the precoated metal sheet according to the embodiment. FIG. [Figure 3] FIG. 3 is a schematic diagram showing another example of the configuration of the coating layer of the precoated metal sheet according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing another example of the configuration of the precoated metal sheet according to the embodiment. [Figure 5] FIG. 2 is a schematic diagram showing an example of the configuration of a surface-treated metal plate according to the embodiment. [Figure 6] FIG. 4 is a schematic diagram showing another example of the configuration of the surface-treated metal sheet according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0012] (About pre-coated metal sheets) <Overall structure of pre-coated metal sheet> First, the overall configuration of a precoated metal sheet according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of a precoated metal sheet according to this embodiment. Note that, for convenience, the following description will be given with appropriate reference to the coordinate system shown in Fig. 1, with the thickness direction of the precoated metal sheet according to this embodiment being defined as the z-axis direction, and the plane spanned by two coordinate axes (x-axis and y-axis) perpendicular to the thickness direction being defined as the xy plane.

[0013] As shown schematically in Figure 1, the precoated metal sheet 1 of this embodiment has a base metal sheet 11, a surface-treated metal sheet 10 having a coating layer 13 provided on the front and back surfaces of the base metal sheet 11, and an upper coating layer 20 located on the surface of the surface-treated metal sheet 10 (more specifically, on the surface of the coating layer 13).

[0014] <About base metal sheet 11> In the precoated metal sheet 1 according to this embodiment, various metal sheets can be used as the base metal sheet 11. Examples of materials for such metal sheets include iron, iron-based alloys, aluminum, aluminum-based alloys, copper, copper-based alloys, and titanium. Furthermore, the base metal sheet 11 can also be a plated metal sheet, which is a metal sheet that has been plated with various metal sheets.

[0015] Furthermore, when a steel plate is used as the base metal plate 11, various steel plates can be used, such as Al-killed steel, ultra-low carbon steel containing Ti, Nb, etc., and high-strength steel in which ultra-low carbon steel further contains strengthening elements such as P, Si, Mn, etc.

[0016] Among the various metal sheets described above, a zinc-based plated steel sheet, which is a steel sheet serving as a substrate and has a zinc-based plating layer containing at least zinc formed on its surface, is preferably used as the base metal sheet 11 according to the present embodiment. Examples of zinc-based plated steel sheets include zinc-plated steel sheets, zinc-nickel-plated steel sheets, zinc-iron-plated steel sheets, zinc-chromium-plated steel sheets, zinc-aluminum-plated steel sheets, zinc-titanium-plated steel sheets, zinc-magnesium-plated steel sheets, zinc-manganese-plated steel sheets, zinc-aluminum-magnesium-plated steel sheets, and zinc-aluminum-magnesium-silicon-plated steel sheets. Furthermore, zinc-based plated steel sheets containing small amounts of different metal elements or impurities, such as cobalt, molybdenum, tungsten, nickel, titanium, chromium, aluminum, manganese, iron, magnesium, lead, bismuth, antimony, tin, copper, cadmium, and arsenic, or those having inorganic substances, such as silica, alumina, and titania, dispersed therein may also be used. Furthermore, the zinc-based plated steel sheet may be a steel sheet having a multi-layer plating that combines the above-mentioned plating with other types of plating (e.g., iron plating, iron-phosphorus plating, nickel plating, cobalt plating, etc.) The plating method is not particularly limited, and various known plating methods such as electroplating, hot-dip plating, vapor deposition plating, dispersion plating, vacuum plating, etc. may be used.

[0017] Among such zinc-based platings, it is particularly preferable to use zinc-aluminum-magnesium (Zn-Al-Mg) alloy plating as the zinc-based plating, and it is more preferable to use zinc-aluminum-magnesium-silicon (Zn-Al-Mg-Si) alloy plating containing 4 to 22 mass% Al, 1 to 10 mass% Mg, 0.0001 to 2.0000 mass% Si, with the remainder being Zn and impurities.

[0018] [Al:4~22% by mass] By setting the Al content to 4% by mass or more, it is possible to further improve the corrosion resistance of the steel sheet. The Al content is more preferably 5% by mass or more. On the other hand, by setting the Al content to 22% by mass or less, it is possible to further improve the corrosion resistance of the steel sheet while suppressing saturation of the corrosion resistance improvement effect as described above. The Al content is more preferably 16% by mass or less.

[0019] [Mg:1~10% by mass] By adjusting the Mg content to 1% by mass or more, it is possible to further improve the corrosion resistance of the steel sheet. The Mg content is more preferably 2% by mass or more. Meanwhile, by adjusting the Mg concentration in the coating bath used to form the coating layer so that the Mg content in the zinc-based coating layer after production is 10% by mass or less, it is possible to stabilize the generation of dross in the coating bath and stably produce coated steel sheets. It is more preferable to adjust the Mg concentration in the coating bath used to form the zinc-based coating layer so that the Mg content in the zinc-based coating layer after production is 5% by mass or less.

[0020] [Si:0.0001~2.0000% by mass] By setting the Si content to 0.0001% by mass or more, it is possible to further improve the adhesion of the zinc-based plating layer (more specifically, the adhesion between the base steel sheet and the zinc-based plating layer). On the other hand, by setting the Si content to 2.0000% by mass or less, it is possible to further improve the adhesion of the zinc-based plating layer while suppressing saturation of the adhesion-improving effect of the zinc-based plating layer. The Si content is more preferably 1.6000% by mass or less.

[0021] Furthermore, the zinc-based plating layer according to this embodiment may contain 1 mass % or less of elements such as Fe, Sb, Pb, etc., either singly or in combination, in place of a portion of the remaining Zn.

[0022] Examples of zinc-based plated steel sheets provided with a zinc-based plating layer having the above-mentioned chemical composition include hot-dip zinc-aluminum-magnesium alloy plated steel sheets having a Zn-6%Al-3%Mg alloy plating layer and hot-dip zinc-aluminum-magnesium-silicon alloy plated steel sheets (for example, "Superdyma (registered trademark)" manufactured by Nippon Steel Corporation), such as plated steel sheets having a Zn-11%Al-3%Mg-0.2%Si alloy plating layer.

[0023] The coating weight of the zinc-based coating layer as described above is 30 g / m2 in total on both sides of the steel sheet. 2 or more (i.e., 15 g / m per side) 2 It is preferable that the coating amount is 30 g / m or more. 2 By setting the coating weight at 40 g / m or more, it is possible to reliably ensure the corrosion resistance of the zinc-based coated steel sheet. 2 On the other hand, the total coating weight on both sides of the steel sheet is 600 g / m 2 (i.e., 300 g / m per side) 2 The coating weight is preferably 600 g / m or less. 2 By setting the coating weight at 550 g / m or less, it is possible to further improve corrosion resistance while ensuring the smoothness of the surface of the zinc-based coating layer. 2 The following is the result.

[0024] In addition, when various plated metal sheets are used as the base metal sheet 11, if a coating layer 13 is provided on the surface of such base metal sheet 11, such coating layer 13 will be located on the surface of various plating layers provided on the plated metal sheet.

[0025] Here, the thickness of the base metal sheet 11 as described above is not particularly limited, and may be set appropriately depending on the mechanical strength (e.g., tensile strength, etc.) and processability required for the precoated metal sheet 1 of this embodiment.

[0026] <<About Coating Layer 13>> The coating layer 13 according to this embodiment is a layer provided on the surface of the base metal sheet 11. The coating layer 13 contains at least a resin, a Zr compound, and a Si compound.

[0027] In the precoated metal sheet 1 according to this embodiment, the coating layer 13 contains the compounds described above, so that when the precoated metal sheet 1 is subjected to drawing, cracks are generated around the Zr compounds present in the coating layer 13 as starting points. The generation of cracks in the coating layer 13 releases residual stress associated with drawing. As a result, the precoated metal sheet 1 according to this embodiment can prevent a decrease in adhesion between the coating layer 13 and the upper coating layer 20, which will be described later. This makes it possible to further improve the coating adhesion during drawing in the precoated metal sheet 1 according to this embodiment.

[0028] The coating layer 13 that realizes the above-mentioned functions will be described in detail below.

[0029] [Average thickness of coating layer 13] In the precoated metal sheet 1 according to this embodiment, the average thickness of the coating layer 13 (thickness d1 in FIG. 1) is 0.5 μm or more and 15.0 μm or less. If the average thickness of the coating layer 13 is less than 0.5 μm, the coating layer 13 is too thin and the corrosion resistance required for the precoated metal sheet 1 cannot be ensured. Furthermore, if the average thickness of the coating layer 13 is less than 0.5 μm, when cracks occur in the coating layer 13 during drawing, the cracks may propagate beyond the coating layer 13 to the upper coating layer 20, reducing the adhesion of the upper coating layer 20. If the average thickness of the coating layer 13 is 0.5 μm or more, the corrosion resistance required for the precoated metal sheet 1 can be ensured while preventing a reduction in adhesion with the upper coating layer 20 during drawing. The average thickness of the coating layer 13 is preferably 1.0 μm or more, and more preferably 3.0 μm or more.

[0030] On the other hand, if the average thickness of the coating layer 13 exceeds 15.0 μm, the average thickness of the coating layer 13 is too large and it is not possible to ensure adhesion between the base metal sheet 11 and the coating layer 13. If the average thickness of the coating layer 13 is 15.0 μm or less, it is possible to ensure adhesion between the base metal sheet 11 and the coating layer 13. The average thickness of the coating layer 13 is preferably 10.0 μm or less, and more preferably 8.0 μm or less.

[0031] The average thickness of the coating layer 13 can be determined by cutting the coating layer 13 along the z-axis direction in FIG. 1 (which can also be considered the thickness direction of the precoated metal sheet 1) and observing the cut surface in a direction perpendicular to the cut surface (cross-sectional direction). Specifically, the average thickness can be measured by observing the cut surface of the coating layer 13 with a microscope in the cross-sectional direction. Examples of methods for preparing a sample for cross-sectional observation include embedding a small piece of the precoated metal sheet 1 provided with the coating layer 13 in resin and polishing the cut surface to be observed, processing with a focused ion beam (FIB), and microtoming. A scanning electron microscope (SEM) can be used as the microscope. The thickness of the coating layer 13 is measured at any number of locations (e.g., three locations) of the obtained sample using the above-described method, using a length measurement function or the like implemented in the microscope. The average thickness of the coating layer 13 can be determined by averaging the multiple measured values ​​obtained for the number of measurement points.

[0032] Furthermore, in a cross section of the precoated metal sheet 1 cut along the thickness direction, it is possible to easily confirm which areas correspond to the base metal sheet 11, the coating layer 13, and the upper coating layer 20 by observing the cross section obtained through a microscope.

[0033] <About the upper coating layer 20> The precoated metal sheet 1 according to this embodiment has an upper coating layer 20 on the coating layer 13 as described above. The upper coating layer 20 contains a film-forming component according to the application, and can be a coating composed of one layer or multiple layers.

[0034] The components contained in the upper coating layer 20 of this embodiment are not particularly limited, and as described above, it is possible for the precoated metal sheet 1 to contain various known components depending on the intended use.

[0035] For example, the upper coating layer 20 according to this embodiment preferably contains a binder resin as a film-forming component as described above. Examples of such binder resins include polymer polyester resins, polyester resins, acrylic resins, epoxy resins, urethane resins, and fluororesins. It is also possible to use film-forming resin components, such as modified versions of these resins, crosslinked with a crosslinking agent component, such as butylated melamine resins, methylated melamine resins, butylmethyl-mixed melamine resins, urea resins, isocyanate resins, or mixtures of these resins. Electron beam-curable resins, ultraviolet-curable resins, and the like may also be used as binder resins.

[0036] The upper coating layer 20 according to this embodiment may contain, as the film-forming components described above, various pigments such as anti-rust pigments, coloring pigments, extender pigments, etc. Furthermore, the upper coating layer 20 according to this embodiment may contain, as the film-forming components described above, various additives such as colorants, viscosity modifiers, leveling agents, antifoaming agents, and ultraviolet absorbers.

[0037] [Average thickness of upper coating layer 20] In the precoated metal sheet 1 according to this embodiment, the upper coating layer 20 has an average thickness (thickness d2 in FIG. 1) of 5.0 μm or more and 30.0 μm or less. If the average thickness of the upper coating layer 20 is less than 5.0 μm, the average thickness of the upper coating layer 20 is too thin and the corrosion resistance required of the precoated metal sheet 1 cannot be ensured. If the average thickness of the upper coating layer 20 is 5.0 μm or more, the corrosion resistance required of the precoated metal sheet 1 can be ensured. The average thickness of the upper coating layer 20 is preferably 10.0 μm or more, and more preferably 15.0 μm or more.

[0038] On the other hand, if the average thickness of the upper coating film layer 20 exceeds 30.0 μm, the average thickness of the upper coating film layer 20 is too large, making it impossible to ensure adhesion between the coating film layer 13 and the upper coating film layer 20. Furthermore, if the average thickness of the upper coating film layer 20 exceeds 30.0 μm, the appearance may be deteriorated due to a coating defect called "popping" caused by the solvent in the paint boiling off during baking. By making the average thickness of the upper coating film layer 20 30.0 μm or less, it is possible to ensure adhesion between the coating film layer 13 and the upper coating film layer 20. The average thickness of the upper coating film layer 20 is preferably 27.0 μm or less, and more preferably 25.0 μm or less.

[0039] The average thickness of the upper coating layer 20 can be measured in the same manner as the method for measuring the average thickness of the coating layer 13 previously explained.

[0040] The overall configuration of the precoated metal sheet 1 according to this embodiment has been described above with reference to FIG. Note that Figure 1 illustrates a case in which the coating layer 13 and the upper coating layer 20 are provided on the front and back surfaces of the base metal plate 11, but in the precoated metal plate 1 of this embodiment, the coating layer 13 and the upper coating layer 20 may be provided on only one of the surfaces of the base metal plate 11.

[0041] <Detailed configuration of coating layer 13> Next, the detailed configuration of the coating layer 13 of the precoated metal sheet 1 according to this embodiment will be described.

[0042] As described above, the precoated metal sheet 1 according to this embodiment has the coating layer 13 containing at least a resin, a Zr compound, and a Si compound and having an average thickness in the range of 0.5 to 10.0 μm.

[0043] Here, whether the coating layer 13 contains a resin, a Zr compound, and a Si compound can be determined by cutting out a sample for cross-sectional observation from any position where the coating layer 13 is present on the precoated metal sheet 1 and observing the sample using a field emission electron probe microanalyzer (FE-EPMA).

[0044] More specifically, an arbitrary position where the coating layer 13 is present is cut to an appropriate size, embedded in resin so that the cross section in the thickness direction can be seen, and the cross section is polished. The resulting polished surface is then observed using an FE-EPMA. More specifically, EPMA mapping analysis of the coating layer 13 on the cross section (polished surface) can be performed at a magnification of 4500x (acceleration voltage: 15 kV). At this time, C, Zr, and Si are selected as the elements to be detected, and mapping images of the locations and concentrations of the C, Zr, and Si elements can be taken.

[0045] In the obtained mapping analysis results, if C element is present in the region corresponding to the coating layer 13, it can be determined that the coating layer 13 contains a resin. Similarly, in the obtained mapping analysis results, if Zr element is present in the region corresponding to the coating layer 13, it can be determined that the coating layer 13 contains a Zr compound, and if Si element is present in the region corresponding to the coating layer 13, it can be determined that the coating layer 13 contains a Si compound.

[0046] [Nanoindenter hardness of cross section] The coating layer 13 according to this embodiment contains the components described above, and when the hardness of the coating layer 13 is measured by pressing an indenter into the cross section of the coating layer 13 with a nanoindenter, there are portions where the nanoindenter hardness is 0.36 GPa or more. The presence of portions where the nanoindenter hardness is 0.36 GPa or more causes cracks to form in the coating layer 13, starting from the portions where the nanoindenter hardness is 0.36 GPa or more, when the precoated metal sheet 1 according to this embodiment is subjected to drawing and stress is applied to the coating layer 13. This releases the residual stress caused by drawing, and peeling of the upper coating layer 20 can be prevented.

[0047] If there is no portion where the nanoindenter hardness is 0.36 GPa or more, there will be no portion in the coating layer 13 that can serve as a starting point for cracks to release the residual stress. As a result, the residual stress caused by the drawing process cannot be released, and the adhesion of the upper coating layer 20 cannot be ensured.

[0048] In the coating layer 13 according to this embodiment, it is preferable that there is a portion where the nanoindenter hardness distribution measured as described above is 0.40 GPa or more, and it is more preferable that there is a portion where the nanoindenter hardness distribution is 0.45 GPa or more.

[0049] On the other hand, in the coating layer 13 according to this embodiment, in the nanoindenter hardness distribution as described above, the nanoindenter hardness is preferably 1.00 GPa or less. If the nanoindenter hardness exceeds 1.00 GPa, the coating layer 13 becomes too hard, and when the residual stress caused by drawing is released, cracks may propagate to the upper coating layer 20. By setting the nanoindenter hardness to 1.00 GPa or less, it is possible to prevent cracks from propagating to the upper coating layer 20 while improving the adhesion of the upper coating layer 20.

[0050] Here, the nanoindenter hardness is measured by performing a nanoindentation test on a cross section obtained by cutting the precoated metal sheet 1 of interest along the z-axis direction shown in Figure 1. More specifically, using a commercially available nanoindenter measurement device (e.g., TI900 TRIBOINDENTER manufactured by HYSITRON) and a Berkovich-type diamond indenter, the obtained cross section is scanned under the following conditions: a measurement temperature of 25°C, a maximum load of 250 μN, and a loading rate of 100 μN / sec.

[0051] Furthermore, in the coating layer 13 according to this embodiment, when the hardness of the coating layer 13 is measured by pressing an indenter into the cross section of the coating layer 13 with a nanoindenter, the average nanoindenter hardness is preferably within the range of 0.31 to 0.80 GPa. Having an average nanoindenter hardness within the range of 0.31 to 0.80 GPa makes it possible to further improve the adhesion of the upper coating layer 20. The average nanoindenter hardness of the coating layer 13 is more preferably 0.35 GPa or more, and even more preferably 0.40 GPa or more. The average nanoindenter hardness of the coating layer 13 is more preferably 0.70 GPa or less, and even more preferably 0.60 GPa or less.

[0052] The average nanoindenter hardness of the coating layer 13 can be obtained by measuring the nanoindenter hardness of the cross section of the coating layer 13 at any multiple positions (for example, 10 positions) under the same measurement conditions as above, and dividing the multiple measurement results by the number of measurement positions.

[0053] [Zr compound content] The content of the Zr compound in the coating layer 13 according to this embodiment is preferably 0.5% by mass or more and 10.0% by mass or less in terms of Zr. If the content of the Zr compound in the coating layer 13 is less than 0.5% by mass in terms of Zr, it is unlikely that a portion having a nanoindenter hardness of 0.36 GPa or more will be formed, and it may be difficult to obtain the effect of improving the adhesion of the upper coating layer 20. By setting the content of the Zr compound to 0.5% by mass or more in terms of Zr, it is possible to further improve the adhesion of the upper coating layer 20. The content of the Zr compound in the coating layer 13 is more preferably 0.8% by mass or more, even more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more in terms of Zr.

[0054] On the other hand, if the content of the Zr compound in the coating layer 13 exceeds 10.0 mass% in terms of Zr, the coating layer 13 may become too hard. As a result, when the residual stress caused by drawing is released, cracks may propagate to the upper coating layer 20, potentially reducing the adhesion of the upper coating layer 20. By setting the content of the Zr compound to 10.0 mass% or less in terms of Zr, it is possible to prevent the propagation of cracks to the upper coating layer 20 as described above, and further improve the adhesion of the upper coating layer 20. The content of the Zr compound in the coating layer 13 is more preferably 9.0 mass% or less, even more preferably 8.0 mass% or less, and even more preferably 7.0 mass% or less in terms of Zr.

[0055] <<Specific examples of Zr compounds>> Here, as the Zr compound contained in the coating layer 13, it is preferable to use a Zr compound capable of functioning as a cross-linking agent, and it is more preferable to use an organic Zr compound capable of functioning as a cross-linking agent. Examples of such Zr compounds include zirconium carbonate complex ions [Zr(CO3)2(OH)2] 2- or [Zr(CO3)3(OH)] 3- Examples of suitable Zr compounds include ammonium salts, potassium salts, and sodium salts of Zr, and organic Zr compounds (for example, organic Zr compounds such as acetylacetonate salts).

[0056] [Si compound content] The content of Si compounds in the coating layer 13 according to this embodiment is preferably 2.0 mass% or more and 40.0 mass% or less in terms of Si. By making the content of Si compounds 2.0 mass% or more in terms of Si, it is possible to further improve the corrosion resistance of the precoated metal sheet 1. The content of Si compounds in the coating layer 13 is more preferably 5.0 mass% or more, even more preferably 8.0 mass% or more, and even more preferably 10.0 mass% or more in terms of Si.

[0057] On the other hand, by setting the content of Si compounds in the coating layer 13 to 40.0 mass % or less in terms of Si, it is possible to further improve the adhesion between the coating layer 13 and the upper coating layer 20. The content of Si compounds in the coating layer 13 is more preferably 35.0 mass % or less, even more preferably 30.0 mass % or less, and even more preferably 25.0 mass % or less, in terms of Si.

[0058] <<Specific examples of Si compounds>> Examples of the Si compound contained in the coating layer 13 include colloidal silica, various inorganic Si compounds, and organic Si compounds (specifically, various silicas and silane coupling agents). Examples of such Si compounds include colloidal silica. Commercially available products include Snowtex O, Snowtex N, and Snowtex C (Nissan Chemical Industries, Ltd.), Adelite AT-20N, and AT-20A (ADEKA). Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylethoxysilane, and N-[2-(vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane. From the viewpoint of liquid stability, it is more preferable to use colloidal silica as the Si compound.

[0059] [Ratio of Zr compound content to Si compound content] In the coating layer 13 according to this embodiment, the ratio ([Si] / [Zr]) of the Si content [Si] to the Zr compound content [Zr] is preferably within the range of 1.00 to 30.00. By setting the ratio ([Si] / [Zr]) within the range of 1.00 to 30.00, it is possible to ensure the corrosion resistance required of the precoated metal sheet 1 while preventing a decrease in adhesion with the upper coating layer 20 during drawing. The ratio ([Si] / [Zr]) is more preferably 2.00 or more, and even more preferably 2.50 or more. Furthermore, the ratio ([Si] / [Zr]) is more preferably 10.00 or less, and even more preferably 8.00 or less.

[0060] [Resin content] The resin content in the coating layer 13 according to this embodiment is preferably 40.0% by mass or more and 80.0% by mass or less. By making the resin content in the coating layer 13 40.0% by mass or more, it is possible to ensure adhesion between the coating layer 13 and the upper coating layer 20 in the unprocessed portion when exposed to a humid environment. The resin content in the coating layer 13 is more preferably 45.0% by mass or more, even more preferably 50.0% by mass or more, and even more preferably 55.0% by mass or more.

[0061] On the other hand, by setting the resin content in the coating layer 13 to 80.0 mass% or less, it is possible to ensure both the corrosion resistance required of the precoated metal sheet 1 and the processing adhesion between the coating layer 13 and the upper coating layer 20. The resin content in the coating layer 13 is more preferably 77.0 mass% or less, even more preferably 73.0 mass% or less, and even more preferably 70.0 mass% or less.

[0062] It is more preferable that such a resin is soft and has good elongation. From this viewpoint, the number average molecular weight of the resin is preferably 8,000 or more, and more preferably 10,000 or more. The number average molecular weight of the resin is preferably 30,000 or less, and more preferably 25,000 or less. The glass transition point (Tg) of the coating film after film formation is preferably 50°C or less, and more preferably 40°C or less. The lower limit of the glass transition point of the coating film is not particularly specified, but is substantially about -10°C. Since the Tg of the coating film after film formation is 10 to 20°C higher than the Tg of the resin, the glass transition point (Tg) of the resin used is preferably 30°C or less, and more preferably 20°C or less.

[0063] In addition, when determining the glass transition point of the resin in the coating layer 13 from the state of the precoated metal sheet 1, the dried coating can be collected by mechanically scraping it off from the precoated metal sheet 1, and the obtained coating sample can be analyzed using a differential scanning calorimeter (DSC).

[0064] <Specific examples of resin> The resin contained in the coating layer 13 according to this embodiment can be any material that functions as a binder for the Zr compound and the Si compound. However, from the viewpoints of ease and cost of production, as well as corrosion resistance and scratch resistance, it is preferable to use various organic resins as the resin. Examples of such resins include urethane resins, polyester resins, and acrylic resins.

[0065] [Method of measuring each content] When the contents of the Zr compound, Si compound, and resin are determined from the state of the precoated metal sheet 1, a cross section of the precoated metal sheet 1 cut in the thickness direction, corresponding to the coating layer 13, can be analyzed by various elemental analysis methods such as FE-EPMA, energy dispersive X-ray spectroscopy (EDS), Auger electron spectroscopy (AES), etc. This makes it possible to determine the contents of the various elements.

[0066] [About particles] The coating layer 13 according to this embodiment may further contain, in addition to the resin, Zr compound, and Si compound as described above, at least one element selected from the group consisting of Si, V, P, Mg, Ca, and Cr, and O, and may further contain particles having an average particle size of 0.5 to 7.0 μm.

[0067] Particles composed of the above elements can function as so-called anti-rust pigments. When the coating layer 13 according to this embodiment further contains particles such as those described above, the corrosion resistance of the precoated metal sheet 1 can be further improved.

[0068] Here, by setting the average particle size of the particles to 0.5 μm or more and 7.0 μm or less, it is possible to prevent the particles from falling off from the coating layer 13 and further improve the corrosion resistance of the precoated metal sheet 1. The average particle size of the particles is more preferably 1.0 μm or more. Furthermore, the average particle size of the particles is more preferably 5.0 μm or less.

[0069] Furthermore, when the coating layer 13 according to the present embodiment contains the above-described particles, the content of the particles is preferably 0.3% by mass or more and 2.0% by mass or less in terms of Si, V, P, Mg, Ca, or Cr. Here, "Si, V, P, Mg, Ca, or Cr" refers to Si-containing particles converted into Si equivalents, V-containing particles converted into V equivalents, P-containing particles converted into P equivalents, Mg-containing particles converted into Mg equivalents, Ca-containing particles converted into Ca equivalents, and Cr-containing particles converted into Cr equivalents. By setting the particle content to 0.3% by mass or more, it becomes possible to achieve the effects described above by including particles. The particle content in the coating layer 13 is more preferably 0.5% by mass or more.

[0070] On the other hand, by setting the particle content to 2.0 mass % or less in terms of Si, V, P, Mg, Ca, or Cr, it becomes possible to achieve the above-mentioned effects of including particles while suppressing a decrease in the stability of the paint used to form the coating layer 13. The particle content in the coating layer 13 is more preferably 1.5 mass % or less.

[0071] Examples of particulate compounds containing at least one of the elements Si, V, P, Mg, Ca, and Cr as described above, and O include zinc phosphate, zinc phosphite, zinc magnesium phosphate, magnesium phosphate, magnesium phosphite, silica, calcium ion-exchanged silica, zirconium phosphate, aluminum dihydrogen tripolyphosphate, calcium tripolyphosphate, zinc oxide, zinc phosphomolybdate, barium metaborate, and strontium chromate.

[0072] Furthermore, when determining whether or not the above-mentioned particles are present in the coating layer 13 from the state of the precoated metal sheet 1, a sample for cross-sectional observation can be cut out from any position where the coating layer 13 of the precoated metal sheet 1 is present, and the sample can be observed using an FE-EPMA.

[0073] More specifically, an arbitrary location where the coating layer 13 is present is cut to an appropriate size, embedded in resin so that the cross section in the thickness direction is visible, and the cross section is polished. The resulting polished surface is then observed using an FE-EPMA. More specifically, EPMA mapping analysis of the coating layer 13 on the cross section (polished surface) can be performed at a magnification of 4500x (acceleration voltage: 15 kV). Si, V, P, Mg, Ca, Cr, and O are selected as the elements to be detected, and mapping images of the locations and concentrations of these elements can be taken.

[0074] If the obtained mapping results show that the location where the element Si, V, P, Mg, Ca, or Cr is present coincides with the location where the element O is present, it can be determined that a particulate compound containing at least one of the elements Si, V, P, Mg, Ca, or Cr and O is present at that location.

[0075] When determining the average particle size of the above-described particles from the state of the precoated metal sheet 1, it can be determined by observing an arbitrary cross section obtained by cutting the precoated metal sheet 1 in the thickness direction using an SEM. More specifically, when the cross section of interest is first observed using an SEM, the particle size of each particle is measured and recorded. Next, the cross section of interest is polished again, and the particle size of each particle on the newly obtained cross section is measured and recorded. If the particle size is larger than the initial measurement, the above-described re-polishing and measurement process is continued. This process is repeated until the particle size becomes smaller than the initial measurement, and the maximum particle size for each particle can be determined. This process is performed on any 10 particles, and the average of the obtained maximum particle sizes of the 10 particles is taken as the average particle size.

[0076] Furthermore, when determining the content of the above-mentioned particles from the state of the precoated metal sheet 1, any cross section obtained by cutting the precoated metal sheet 1 in the thickness direction can be subjected to mapping analysis using FE-EPMA for the elements Si, V, P, Mg, Ca, and Cr, and the obtained amounts of Si, V, P, Mg, Ca, and Cr can be added together.

[0077] In addition to the particles described above, the coating layer 13 according to this embodiment may contain various additives, such as extender pigments, coloring pigments, colorants, viscosity adjusters, leveling agents, antifoaming agents, and ultraviolet absorbers, as needed.

[0078] [Phase structure of coating layer 13] In the coating layer 13 according to this embodiment, when the content of the Zr compound is 3.0 mass % or more in terms of Zr, a phase structure having Phase A and Phase B as described below is realized in the coating layer 13. Hereinafter, the phase structure that the coating layer 13 according to this embodiment may have will be described in detail with reference to Figures 2 and 3. Figure 2 is a schematic diagram showing one example of the structure of the coating layer that the precoated metal sheet according to this embodiment has, and Figure 3 is a schematic diagram showing another example of the structure of the coating layer that the precoated metal sheet according to this embodiment has.

[0079] FIG. 2 is an enlarged schematic view of a cross section of the coating layer 13 according to this embodiment cut in the thickness direction. In the coating layer 13 according to this embodiment, when the content of the Zr compound is 3.0% by mass or more in terms of Zr, as shown schematically in FIG. 2, the coating layer 13 includes two phases with different nanoindenter hardnesses: Phase A (reference numeral 101 in FIG. 2) and Phase B (reference numeral 103 in FIG. 2). Phase A exhibits a higher nanoindenter hardness than Phase B. The nanoindenter hardness of the coating layer 13 was measured at 20 points according to the method described above. The maximum, minimum, and four middle values ​​were excluded. The upper group (seven points in descending order of nanoindenter hardness) were designated Phase A, and the lower group (seven points in descending order of nanoindenter hardness) were designated Phase B. The measurement points were located at ±10% of the center position in the thickness direction of the coating layer 13 (the z-axis direction in FIG. 1), and the measurement pitch was 10 μm in the planar direction (the y-axis direction in FIG. 1).

[0080] Here, we analyzed the above-mentioned phases A and B and found that phase A, which exhibits a higher nanoindenter hardness, is a phase in which Zr compounds and Si compounds co-localize in the resin, and phase B, which exhibits a lower nanoindenter hardness than phase A, is a phase composed mainly of resin. In other words, phase A (reference numeral 101 in Figure 2) can be considered a Zr / Si-containing phase, and phase B (reference numeral 103 in Figure 2) can be considered a resin phase.

[0081] Furthermore, the chemical compositions of the above-mentioned phases A and B were analyzed by point EDS, focusing on the indentation marks made during nanoindenter measurement. It was found that the ratio of the Zr concentration in phase A to the Zr concentration in phase B (each in mass%) was 1.5 to 6.0, and that the ratio of the Si concentration in phase A to the Si concentration in phase B (each in mass%) was 1.6 to 10.0.

[0082] <Relationship between nanoindenter hardness in Phase A and Phase B> In the coating layer 13 according to this embodiment, when the nanoindenter hardness of each of the phases A (Zr·Si-containing phase) 101 and B (resin phase) 103 specified as described above is measured in accordance with the measurement conditions previously described, it is preferable that the phase A (Zr·Si-containing phase) 101 and the phase B (resin phase) 103 satisfy both of the following formulas (1) and (2): H IT·B <H IT·A ...Equation (1) 1.1 ≦ H IT·A / H IT·B < 2.0...Equation (2)

[0083] Here, in the above formulas (1) and (2), H IT·A : Average nanoindenter hardness of phase A H IT·B : Average nanoindenter hardness of phase B The average nanoindenter hardness of each phase can be obtained by dividing the multiple measurement values ​​obtained for phase A and phase B, which are determined in accordance with the method described above, by the number of measurements in the cross section of interest.

[0084] In the coating layer 13 according to this embodiment, when both the above formulas (1) and (2) are satisfied, cracks for releasing residual stress caused by drawing are more likely to occur in the coating layer 13 within a range that does not propagate to the upper coating layer 20, and the adhesion of the upper coating layer 20 can be further improved. Here, the ratio H in formula (2) IT·A / H IT·B The value of is more preferably 1.2 or more, and further preferably 1.3 or more. IT·A / H IT·B The value is more preferably 1.9 or less, and even more preferably 1.8 or less.

[0085] <Relationship between Zr and Si concentrations in Phases A and B> In the coating layer 13 according to this embodiment, it is preferable that the phase A (Zr·Si-containing phase) 101 and the phase B (resin phase) 103 specified as described above satisfy both of the following formulas (3) and (4). 1.5 ≦ N Zr·A / N Zr·B ≦ 6.0...Equation (3) 1.5 ≦ N Si·A / N Si·B ≦ 10.0...Equation (4)

[0086] Here, in the above formulas (3) and (4), N Zr·A : Average Zr concentration in phase A (mass%) N Zr·B : Average Zr concentration of phase B (mass%) N Si·A : Average Si concentration in phase A (mass%) N Si·B : Average Si concentration in phase B (mass%) The average Zr concentration and the average Si concentration in phase A can be determined by measuring each of phases A defined in accordance with the method described above using FE-EPMA and averaging the obtained Zr and Si concentrations. Similarly, the average Zr concentration and the average Si concentration in phase B can be determined by measuring each of phases B defined in accordance with the method described above using FE-EPMA and averaging the obtained Zr and Si concentrations.

[0087] In the coating layer 13 according to this embodiment, both of the above formulas (3) and (4) are satisfied, and therefore, in the coating layer 13, it is possible to prevent cracks from propagating to the upper coating layer 20, and to further improve the adhesion of the upper coating layer 20. Here, the ratio N in formula (3) Zr·A / N Zr·B The value of is more preferably 2.0 or more, and further preferably 3.0 or more. Zr·A / N Zr·B The value of is more preferably 5.0 or less, and further preferably 4.0 or less. Si·A / N Si·BThe value of is more preferably 2.0 or more, and further preferably 3.0 or more. Si·A / N Si·B The value is more preferably 9.0 or less, and even more preferably 8.0 or less.

[0088] ≪Average area ratio of Phase A and Phase B≫ Furthermore, in the coating layer 13 according to this embodiment, when a cross section of the coating layer 13 cut along the thickness direction (z-axis direction in FIG. 1 ) is observed by SEM, the average area ratio of the phase A (Zr·Si-containing phase) is preferably within a range of 20 to 70%. For the coating layer 13 according to this embodiment, when the average area ratio of the phase A (Zr·Si-containing phase) is 20 to 70%, cracks that release residual stress caused by drawing are more likely to occur in the coating layer 13 within a range that does not propagate to the upper coating layer 20, thereby further improving the adhesion of the upper coating layer 20. Here, the average area ratio of the phase A (Zr·Si-containing phase) is more preferably 30% or more, and even more preferably 40% or more. Furthermore, the average area ratio of the phase A (Zr·Si-containing phase) is more preferably 65% ​​or less, and even more preferably 60% or less.

[0089] Furthermore, in the coating layer 13 according to this embodiment, when a cross section of the coating layer 13 cut along the thickness direction (z-axis direction in FIG. 1) is observed by SEM, it is preferable that the average area ratio of the phase B (resin phase) is in the range of 30 to 80%.

[0090] The average area ratios of phase A and phase B as described above are determined by observing an arbitrary region in a cross section of the coating layer 13 cut along the thickness direction (z-axis direction in FIG. 1) with an SEM in a 15 μm × 15 μm field of view, and measuring the area ratios of phase A and phase B in the field of view using a length measurement function or the like implemented in the SEM. Such measurements are performed at arbitrary three locations, and the average value of the area ratios obtained at each measurement location over the number of measurement fields is taken as the average area ratio of each phase.

[0091] When the coating layer 13 according to this embodiment further contains a particulate compound containing at least one of Si, V, P, Mg, Ca, and Cr, and O, the particulate compound may be present in either of the above-mentioned phase A (Zr·Si-containing phase) 101 and phase B (resin phase) 103. In this case, when a cross section of the coating layer 13 is observed by SEM, particles are observed in phase A (Zr·Si-containing phase) 101 and phase B (resin phase) 103, as schematically shown in FIG.

[0092] The mechanism by which the above-mentioned phases A and B are formed in the coating layer 13 when the content of Zr compounds is 3.0 mass% or more in terms of Zr is not yet clear. However, it is presumed that when the content of Zr compounds is 3.0 mass% or more in terms of Zr, there is an excess of Zr relative to the number of crosslinking points in the resin, which causes phase separation.

[0093] The coating layer 13 of the precoated metal sheet 1 according to this embodiment has been described in detail above with reference to FIGS.

[0094] <Modification> Next, a modified example of the precoated metal sheet 1 according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing another example of the configuration of the precoated metal sheet according to this embodiment.

[0095] As shown schematically in Figure 4, the precoated metal sheet 1 according to this embodiment may further have a base coating layer 15 between the base metal sheet 11 and the coating layer 13, the base coating layer 15 having an average thickness (thickness d3 in Figure 4) of 0.05 to 2.00 µm.

[0096] Here, various chemical conversion treatment layers can be cited as examples of such an undercoat coating layer 15. The presence of a chemical conversion treatment layer, which is an example of the undercoat coating layer 15, between the base metal sheet 11 and the coating layer 13 can further improve the adhesion between the base metal sheet 11 and the coating layer 13. Furthermore, the presence of such a chemical conversion treatment layer can further improve the corrosion resistance of the precoated metal sheet 1.

[0097] The chemical conversion treatment layer is not particularly limited, and may be formed using various chemical conversion treatments. Examples of such chemical conversion treatments include chromate-based chemical conversion treatments and non-chromate-based chemical conversion treatments. Examples of non-chromate-based chemical conversion treatments include chemical conversion treatments using inorganic compounds such as vanadium compounds, titanium compounds, zirconium compounds, and phosphate compounds, and silica-based chemical conversion treatments.

[0098] The average thickness of the base coating layer 15 can be measured in the same manner as the average thickness of the coating layer 13 .

[0099] The modified example of the precoated metal sheet 1 according to this embodiment has been briefly described above with reference to FIG.

[0100] (About surface-treated metal sheets) Next, a surface-treated metal sheet as a material for the precoated metal sheet 1 as described above will be briefly described with reference to Figures 5 and 6. Figure 5 is a schematic diagram showing an example of the configuration of a surface-treated metal sheet according to this embodiment, and Figure 6 is a schematic diagram showing another example of the configuration of a surface-treated metal sheet according to this embodiment. Note that, for convenience, the following description will be given with appropriate reference to the coordinate systems shown in Figures 5 and 6, with the thickness direction of the surface-treated metal sheet according to this embodiment defined as the z-axis direction, and the plane spanned by two coordinate axes (x-axis and y-axis) perpendicular to the thickness direction defined as the xy plane.

[0101] The surface-treated metal sheet 10 according to this embodiment, which is used as a material for the precoated metal sheet 1 as described above, has a base metal sheet 11 and a coating layer 13, as shown schematically in FIG.

[0102] Here, the base metal plate 11 of the surface-treated metal plate 10 of this embodiment has a configuration similar to that of the base metal plate 11 in the precoated metal plate 1 described earlier, and produces similar effects, so detailed explanations will be omitted below.

[0103] Furthermore, the coating layer 13 of the surface-treated metal sheet 10 according to this embodiment is a layer containing a resin, a Zr compound, and a Si compound, and having an average thickness of 0.5 to 15.0 μm. When the hardness of the coating layer 13 is measured by pressing an indenter into the cross section of the coating layer 13 using a nanoindenter, there are portions where the nanoindenter hardness is 0.36 GPa or more.

[0104] The coating layer 13 of the surface-treated metal sheet 10 of this embodiment as described above has the same configuration as the coating layer 13 in the pre-coated metal sheet 1 described earlier and has the same effect, so detailed explanation will be omitted below.

[0105] Furthermore, as shown schematically in Figure 6, the surface-treated metal sheet 10 according to this embodiment may further have a base coating layer 15 between the base metal sheet 11 and the coating layer 13, the base coating layer 15 having an average thickness (thickness d3 in Figure 6) of 0.05 to 2.00 µm.

[0106] Here, the base coating layer 15 of the surface-treated metal sheet 10 of this embodiment has the same configuration as the base coating layer 15 in the precoated metal sheet 1 described earlier and has the same effects, so detailed explanation will be omitted below.

[0107] The surface-treated metal sheet 10 according to this embodiment has been briefly described above with reference to FIGS.

[0108] (About the parts) Various components can be formed by using the precoated metal sheet 1 according to this embodiment as described above as a material and performing various processes, such as bending and drawing, to achieve a desired shape on the precoated metal sheet 1. In this way, the components according to this embodiment can be said to be components formed by performing processes on the precoated metal sheet 1.

[0109] The member according to this embodiment comprises a metal plate as a substrate, a coating layer located on at least one surface of the metal plate and containing a resin, a Zr compound, and a Si compound, and an upper coating layer located on the coating layer. In a 1 cm x 1 cm area of ​​the member, the coating layer has an average thickness of 0.5 to 15.0 μm, the upper coating layer has an average thickness of 5.0 to 30.0 μm, and when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more.

[0110] Specific examples of such members are not particularly limited, and include various members such as members for home appliances, building materials, interior materials, and automobile members.

[0111] (Regarding the manufacturing method of the surface-treated metal sheet 10 and the pre-coated metal sheet 1) An example of a method for manufacturing the surface-treated metal sheet 10 and the precoated metal sheet 1 according to this embodiment will be briefly described below. First, the metal plate serving as the substrate is subjected to various pretreatments, such as alkaline degreasing, water washing, and pickling, as needed, to obtain a clean metal plate surface. Then, the surface of the substrate metal plate 11 may be subjected to various plating treatments as needed. In this manner, the substrate metal plate 11 of the surface-treated metal plate 10 and the precoated metal plate 1 according to this embodiment can be obtained.

[0112] If necessary, various known processes are performed on the base metal sheet 11 to form a primer coating layer 15 (e.g., a chemical conversion coating layer). For example, a primer coating containing the desired components (e.g., various known chemical conversion coating agents) is prepared, and the primer coating is applied to the surface of the base metal sheet 11 and then dried. The application of the primer coating described above can be carried out by a commonly known application method, such as roll coating, curtain flow coating, air spraying, airless spraying, dipping, bar coating, or brush coating. The primer coating can also be dried by a commonly known drying method, such as hot air, near infrared rays, far infrared rays, induction heating, or a combination of these.

[0113] For example, a paint for forming the coating layer 13 is applied to the surface of the base metal sheet 11 (or the base coating layer 15) formed as described above, and then heated and dried to form the coating layer 13. Here, such a paint is prepared by adding the above-mentioned resin, Zr compound, and Si compound to water (e.g., pure water) as a solvent, and, if necessary, particles containing specific elements and various additives to achieve specific contents. In this way, the paint used to form the coating layer 13 is a so-called water-based paint.

[0114] The prepared coating material for forming the coating film layer can be applied by a commonly known application method, such as roll coating, curtain flow coating, air spraying, airless spraying, dipping, bar coating, or brush coating, as described above.

[0115] The paint can then be heated and dried by any method, such as hot air, near-infrared rays, far-infrared rays, induction heating, or a combination of these. This allows the coating layer 13 of this embodiment to be formed. However, from the perspective of reducing CO2 emissions, heating and drying by induction heating is preferred, as it is more energy efficient than hot air. Furthermore, with induction heating, the coating is heated from the steel sheet side, which facilitates convection of Zr and Si components in the coating, making Zr and Si more likely to aggregate. This makes it possible to form a coating layer 13 with a more desirable hardness.

[0116] Here, the maximum plate temperature reached when the paint is heated and dried is within the range of 100 to 250°C. If the maximum plate temperature is less than 100°C, evaporation of the water, which is the solvent of the paint, will be insufficient, which is undesirable. By setting the maximum plate temperature to 100°C or higher, it becomes possible to sufficiently evaporate the water, which is the solvent of the paint, and the coating film layer 13 according to this embodiment can be formed. The maximum plate temperature reached when the paint is heated and dried is preferably above 100°C, more preferably 120°C or higher, and even more preferably 150°C or higher.

[0117] On the other hand, if the maximum plate temperature when the paint is heated and dried exceeds 250°C, thermal decomposition of the resin contained in the paint will begin, which is undesirable. By setting the maximum plate temperature to 250°C or less, the coating film layer 13 according to this embodiment can be formed while preventing thermal decomposition of the resin in the paint. The maximum plate temperature when the paint is heated and dried is preferably 230°C or less, and more preferably 210°C or less.

[0118] <About the temperature rise rate when heating and drying paint> Here, in order to ensure the adhesion of the coating film layer 13 according to this embodiment, it is important to appropriately control the rate of temperature increase up to 100°C, at which the components in the paint are flowing. The appropriate rate of temperature increase up to the sheet temperature of 100°C also varies depending on the concentration, in terms of Zr, of the Zr compound in the paint for forming the coating film layer.

[0119] When the content of Zr compounds in the coating material is less than 3.0% by mass (e.g., 0.5% by mass or more and less than 3.0% by mass) calculated as Zr, the heating rate to a sheet temperature of 100°C should be within the range of 2 to 30°C / sec. If the heating rate is less than 2°C / sec or more than 30°C / sec, the resin, Zr compounds, and Si compounds in the coating material will not crosslink sufficiently, making it impossible to achieve the desired adhesion. By setting the heating rate to a sheet temperature of 100°C within the range of 2 to 30°C / sec, it becomes possible to sufficiently crosslink the resin via Zr. This allows cracks to form in the crosslinked parts with low elasticity during processing, making it possible to appropriately release residual stress caused by processing and achieving good adhesion.

[0120] When the content of Zr compounds in the coating material is less than 3.0 mass% (e.g., 0.5 mass% or more and less than 3.0 mass%) in terms of Zr, the rate of temperature rise up to a sheet temperature of 100°C is preferably within the range of 2 to 30°C / sec, more preferably within the range of 5 to 25°C / sec, and even more preferably within the range of 10 to 20°C / sec.

[0121] On the other hand, when the Zr compound content in the coating is 3.0% by mass or more (e.g., 3.0% by mass or more and 10.0% by mass or less) in terms of Zr, the heating rate to a sheet temperature of 100°C should be within the range of 4 to 50°C / s. By setting the heating rate to 100°C within the range of 4 to 50°C / s, not only does Zr crosslink the resin, but the excess Zr also phase-separates into a Zr·Si-containing phase (i.e., Phase A). As a result, Phase A (the Zr·Si-containing phase) is more likely to initiate cracks during processing, which allows for the appropriate release of residual stress due to processing and achieves good adhesion. If the heating rate is less than 4°C / s, the Zr·Si-containing phase becomes excessive, resulting in poor adhesion of the coating layer 13. On the other hand, if the heating rate is greater than 50°C / s, the resin, Zr compound, and Si compound in the coating do not crosslink sufficiently, making it impossible to achieve the desired adhesion.

[0122] When the content of the Zr compound in the coating material is 3.0 mass % or more (e.g., 3.0 mass % or more and 10.0 mass % or less) converted to Zr, the rate of temperature rise up to a sheet temperature of 100°C is preferably within the range of 4 to 50°C / sec, and more preferably within the range of 10 to 40°C / sec.

[0123] There are no particular limitations on the rate of temperature rise in the range of plate temperatures exceeding 100°C during heating and drying of the paint. The plate temperature and rate of temperature rise described above can be easily measured using various known measuring devices such as a thermocouple or a radiation thermometer.

[0124] By going through the steps described above, it is possible to manufacture the surface-treated metal sheet 10 that serves as the material for the precoated metal sheet 1 according to this embodiment.

[0125] When manufacturing the precoated metal sheet 1 according to this embodiment, a paint for forming the desired upper coating layer 20 is further applied to the surface of the surface-treated metal sheet 10 manufactured as described above (more specifically, the surface of the coating layer 13), and then heated and dried.

[0126] Here, there are no particular limitations on the paint for forming the upper coating layer 20, and various known paints can be used. As with the above, the paint for forming the upper coating layer can be applied by a generally known application method, such as roll coating, curtain flow coating, air spraying, airless spraying, dipping, bar coating, or brush coating.

[0127] Thereafter, the paint can be heated and dried by any method, such as hot air, near infrared rays, far infrared rays, induction heating, or a combination of these, to form the upper coating layer 20 according to this embodiment.

[0128] By going through the steps described above, the precoated metal sheet 1 according to this embodiment can be manufactured. [Example]

[0129] The surface-treated metal sheet and precoated metal sheet according to the present embodiment will be specifically described below with reference to examples and comparative examples. Note that the examples shown below are merely examples of the surface-treated metal sheet and precoated metal sheet according to the present embodiment, and the surface-treated metal sheet and precoated metal sheet according to the present invention are not limited to the examples below.

[0130] <Preparing the metal plate> In the test examples shown below, metal plates with a thickness of 0.6 mm, as shown in Table 1 below, were prepared and used as substrates. The steel plates designated GI, ZAM, SD, and ZX below are all manufactured by Nippon Steel Corporation. Commercially available aluminum (AL) and stainless steel (SUS) were also used as substrates.

[0131] A chemical conversion treatment agent (CT-E215 manufactured by Nihon Parkerizing Co., Ltd.) was applied to the surface of the metal plate described above using a bar coater so that the average thickness after drying would be the values ​​shown in Tables 6-1 to 6-3 below, and then dried by heating. This formed a chemical conversion treatment layer as an example of a base coating layer on the surface of the metal plate.

[0132] [Table 1]

[0133] <Paint for forming coating layer> The compounds shown below were used to prepare paints for forming coating layers. Table 2 shows the resins used, Table 3 shows the Zr compounds used, Table 4 shows the Si compounds used, and Table 5 shows the particles used. All of the substances shown in Tables 3 to 5 were commercially available general reagents. These compounds were blended at the amounts shown in Tables 6-1 to 6-3 below to prepare paints for forming coating layers.

[0134] [Table 2]

[0135] [Table 3]

[0136] [Table 4]

[0137] [Table 5]

[0138] <Formation of coating layer> The paint prepared as described above was applied using a bar coater to the surface of the metal plate described above (or to the surface of the base coating layer in the case of a metal plate on which a base coating layer had been formed), and then the applied paint was heated and dried by induction heating to form a coating layer.

[0139] <Formation of upper coating layer> Flexicoat 5100 manufactured by Nippon Paint Industrial Coatings Co., Ltd. was prepared as the paint for forming the upper coating layer, and was applied to the surface of the coating layer formed as described above using a bar coater, followed by heating and drying to form the upper coating layer.

[0140] In this manner, a plurality of precoated metal sheets as shown in Tables 6-1 to 6-3 below were produced for each level.

[0141] [Table 6-1]

[0142] [Table 6-2]

[0143] [Table 6-3]

[0144] The paints prepared as described above were evaluated from the viewpoint of paint stability. Details of the paint stability test method and evaluation criteria are as follows. The obtained evaluation results are summarized in Tables 7-1 to 7-3 below.

[0145] [Paint stability evaluation] After preparing each paint, it was left at 25±3°C and its stability over time was investigated. The liquid state was observed and evaluated based on the period during which it maintained its fluidity without any change from the initial state. A rating of 3, 4, or 5 was considered a pass. <Evaluation criteria> Rating 5: 3 weeks or more 4: 2 weeks or more but less than 3 weeks 3: 1 week or more but less than 2 weeks 2: More than 3 days but less than 1 week 1: Less than 3 days

[0146] Furthermore, for each precoated metal plate obtained, the cross section was scanned using a nanoindenter measuring device (e.g., TI900 TRIBOINDENTER manufactured by HYSITRON) and a Berkovich-type diamond indenter at a measurement temperature of 25°C, a maximum load of 250 μN, and a loading rate of 100 μN / sec to measure the nanoindenter hardness. Furthermore, the chemical compositions of phases A and B were measured by EDS point analysis. Furthermore, the average area ratio of phase A was measured by SEM.

[0147] Furthermore, each of the obtained precoated metal sheets was evaluated from the viewpoints of drawing compound adhesion, bending adhesion, corrosion resistance, and cross-cut Erichsen test. Details of the test method for each item and the evaluation criteria are as follows. The obtained evaluation results are summarized in Tables 7-1 to 7-3 below.

[0148] [Paint adhesion evaluation test 1: Cross-cut Erichsen processing] This test evaluated the primary adhesion of the paint film. Primary adhesion refers to the paint film adhesion after application and before actual use. This test was performed by placing 100 squares at 1 mm intervals on each pre-coated metal plate, extruding the plate to a depth of 7 mm using an Erichsen method at 20°C, then applying adhesive tape and peeling it off to measure the paint film remaining rate. The test method and tape type were in accordance with JIS K5600-5-6:1999, and the procedure was in accordance with JIS K5981:2006. Evaluation was based on the number of remaining squares (X / 100) out of 100. The evaluation criteria were as follows, with a rating of 3, 4, or 5 being considered a pass. <Evaluation criteria> Rating 5:100 / 100 4:95~99 / 100 3:90~94 / 100 2:50~89 / 100 1:49 or less / 100

[0149] [Paint adhesion evaluation test 2: bending] This test evaluated the secondary adhesion of the coating film in the processed area that had undergone plastic processing. Secondary adhesion refers to the coating film's performance after use. For this test, the precoated metal sheet was bent 180° (tight bending) according to the bending test of JIS G3322:2019, and the coating film in the processed area was visually inspected for cracks. The 180° bending was performed with the surface of the precoated metal sheet facing outward (commonly known as 0T bending). The test method and tape type were in accordance with JIS K5600-5-6:1999, and the procedure was in accordance with JIS K5981:2006. The evaluation criteria were as follows, with a rating of 3, 4, or 5 being considered a pass. <Evaluation criteria> Rating 5: No peeling of the coating film and no cracks in the coating film before application 4: No peeling of the coating, but slight cracks in the coating before application 3: No peeling of the coating, but slight cracks in the coating before application 2: Slight peeling of the paint film 1: Most of the paint has peeled off

[0150] [Paint adhesion evaluation test 3: cylindrical drawing] This test evaluates the secondary adhesion of the paint film, and evaluates the paint film adhesion in the processed areas that have been plastically processed. This test was conducted by cylindrically drawing each pre-coated metal sheet under the conditions shown below, making a cross-cut that reached the base metal sheet, immersing the sheet in boiling water for one hour, and then visually evaluating the width of the paint film blister after removal. The evaluation criteria are as follows, with a rating of 3, 4, or 5 being considered a pass. <Cylindrical drawing conditions> Punch diameter: 50 mm Punch shoulder R: 5mm, Die diameter: 52.5mm Die shoulder R: 5mm Wrinkle suppression force: 4900N Squeeze speed: 20 mm per minute The coated surface was the die side, and the uncoated surface was the punch side. <Evaluation criteria> Score 5: Blister width less than 0.3 mm 4: Bulge width 0.3mm or more, less than 0.5mm 3: Blister width 0.5mm or more, less than 1.0mm 2: Bulge width 1.0mm or more, less than 1.5mm 1: Bulge width 1.5mm or more

[0151] [Corrosion resistance evaluation test] Each precoated metal sheet had a cross-cut that reached the base metal sheet, and was subjected to a salt spray test (JIS Z 2371:2015). After 480 hours, the width of the coating blister at the cross-cut was measured. The evaluation criteria were as follows, with a score of 3, 4, or 5 being considered a pass. <Evaluation criteria> Grade 5: Blister width less than 1.0 mm 4: Bulge width 1.0mm or more, less than 1.5mm 3: Bulge width 1.5mm or more, less than 2.0mm 2: Bulge width 2.0mm or more, less than 3.0mm 1: Bulge width 3.0mm or more

[0152] [Table 7-1]

[0153] [Table 7-2]

[0154] [Table 7-3]

[0155] As is clear from Tables 6-1 to 7-3 above, the precoated metal sheets corresponding to the examples of the present invention exhibited excellent adhesion of the drawn portion while maintaining corrosion resistance, whereas the precoated metal sheets corresponding to the comparative examples of the present invention failed in at least one of corrosion resistance or adhesion of the drawn portion.

[0156] 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 these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0157] The embodiments disclosed herein are illustrative in all respects and are not limiting. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope of the appended claims, the technical scope of the present invention as described below, and the spirit thereof. For example, the components of the above-described embodiments may be arbitrarily combined within the scope that does not impair the effects of the components. Furthermore, such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0158] Furthermore, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present invention may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0159] The following configurations also fall within the technical scope of the present invention. (1) a metal plate as a substrate; a coating layer located on at least one surface of the metal plate; an upper coating layer located on the coating layer; and the coating layer contains a resin, a Zr compound, and a Si compound; The coating layer has an average thickness of 0.5 to 15.0 μm, The upper coating layer has an average thickness of 5.0 to 30.0 μm, A precoated metal sheet in which, when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer using a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more. (2) The precoated metal sheet according to (1), wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass % in terms of Zr. (3) the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The precoated metal sheet according to (2), wherein the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H IT·B <H IT·A ...Equation (1) 1.1 ≦ H IT·A / H IT·B < 2.0...Equation (2) Here, in the above formulas (1) and (2), H IT·A : Average nanoindenter hardness of the phase A H IT·B : Average nanoindenter hardness of the phase B is. (4) the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The phase A and the phase B of the coating layer satisfy the following formulas (3) and (4), (3) The precoated metal sheet according to (3), wherein, when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Zr·A / N Zr·B ≦ 6.0...Equation (3) 1.5 ≦ N Si·A / N Si·B ≦ 10.0...Equation (4) Here, in the above formulas (3) and (4), N Zr·A : Average Zr concentration (mass%) of the phase A N Zr·B : Average Zr concentration of the phase B (mass%) N Si·A : Average Si concentration (mass%) of the phase A N Si·B : Average Si concentration of the phase B (mass%) is. (5) The precoated metal sheet according to any one of (1) to (4), wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.00. (6) The precoated metal sheet according to any one of (1) to (5), wherein the resin is at least one of a urethane-based resin, a polyester-based resin, and an acrylic-based resin. (7) The precoated metal sheet according to any one of (1) to (6), further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer. (8) the coating layer further contains particles containing at least one element of Si, V, P, Mg, Ca, or Cr, and O, and having an average particle size of 0.5 to 7.0 μm; The precoated metal sheet according to any one of (1) to (7), wherein the content of the particles is 2.0 mass % or less in terms of Si, V, P, Mg, Ca, or Cr. (9) A precoated metal sheet according to any one of (1) to (8), wherein the hardness of the coating layer is measured by pressing an indenter into the cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. (10) The precoated metal sheet according to any one of (1) to (9), wherein the metal sheet is a Zn-plated steel sheet having a Zn-plated layer on at least one surface of the steel sheet. (11) The precoated metal sheet according to (10), wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg. (12) A member having a predetermined shape, The member is a metal plate as a substrate; a coating layer located on at least one surface of the metal plate, the coating layer containing a resin, a Zr compound, and a Si compound; an upper coating layer located on the coating layer; It is composed of, and In a 1 cm x 1 cm area of ​​the member, The coating layer has an average thickness of 0.5 to 15.0 μm, The upper coating layer has an average thickness of 5.0 to 30.0 μm, A member having a portion where the hardness of the coating layer is 0.36 GPa or more when the hardness is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter. (13) a metal plate as a substrate; a coating layer located on at least one surface of the metal plate; and the coating layer contains a resin, a Zr compound, and a Si compound; The coating layer has an average thickness of 0.5 to 15.0 μm, A surface-treated metal sheet in which, when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer using a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more. (14) (14) The surface-treated metal sheet according to (13), wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass % in terms of Zr. (15) the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The surface-treated metal sheet according to (13) or (14), wherein the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H IT·B <H IT·A ...Equation (1) 1.1 ≦ H IT·A / H IT·B < 2.0...Equation (2) Here, in the above formulas (1) and (2), H IT·A : Average nanoindenter hardness of the phase A H IT·B : Average nanoindenter hardness of the phase B is. (16) the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The phase A and the phase B of the coating layer satisfy the following formulas (3) and (4), (16) The surface-treated metal sheet according to (15), wherein, when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Zr·A / N Zr·B ≦ 6.0...Equation (3) 1.5 ≦ N Si·A / N Si·B ≦ 10.0...Equation (4) Here, in the above formulas (3) and (4), NZr·A : Average Zr concentration (mass%) of the phase A N Zr·B : Average Zr concentration of the phase B (mass%) N Si·A : Average Si concentration (mass%) of the phase A N Si·B : Average Si concentration of the phase B (mass%) is. (17) The surface-treated metal sheet according to any one of (13) to (16), wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.00. (18) The surface-treated metal sheet according to any one of (13) to (17), wherein the resin is at least one of a urethane-based resin, a polyester-based resin, and an acrylic-based resin. (19) The surface-treated metal sheet according to any one of (13) to (20), further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer. (20) the coating layer further contains particles containing at least one element of Si, V, P, Mg, Ca, or Cr, and O, and having an average particle size of 0.5 to 7.0 μm; The surface-treated metal sheet according to any one of (13) to (19), wherein the content of the particles is 2.0 mass % or less in terms of Si, V, P, Mg, Ca, or Cr. (twenty one) The surface-treated metal sheet according to any one of (13) to (20), wherein the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. (twenty two) The surface-treated metal sheet according to any one of (13) to (21), wherein the metal sheet is a Zn-plated steel sheet having a Zn-plated layer on at least one surface of the steel sheet. (twenty three) The surface-treated metal sheet according to (22), wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg. [Explanation of symbols]

[0160] 1 Pre-coated metal sheet 10. Surface-treated metal plate 11 Base metal plate 13 Coating layer 15 Base coating layer 20 Upper coating layer 101 Phase A (Zr·Si containing phase) 103 Phase B (resin phase) 105 particles

Claims

1. a metal plate as a substrate; a coating layer located on at least one surface of the metal plate; an upper coating layer located on the coating layer; and the coating layer contains a resin, a Zr compound, and a Si compound; The coating layer has an average thickness of 0.5 to 15.0 μm, the average thickness of the upper coating layer is 5.0 to 30.0 μm; A precoated metal sheet, wherein when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more.

2. 2. The precoated metal sheet according to claim 1, wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass % in terms of Zr.

3. the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The precoated metal sheet according to claim 2 , wherein the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H ＩＴ・Ｂ <H ＩＴ・Ａ Formula (1) 1.1 ≦ H ＩＴ・Ａ / H ＩＴ・Ｂ < 2.0 ・・・Formula (2) Here, in the above formula (1) and formula (2), H ＩＴ・Ａ : Average nanoindenter hardness of the phase A H ＩＴ・Ｂ : Average nanoindenter hardness of the phase B is.

4. the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The phase A and the phase B of the coating layer satisfy the following formulas (3) and (4), 4. The precoated metal sheet according to claim 3, wherein when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Ｚｒ・Ａ / N Ｚｒ・Ｂ ≦ 6.0 ・・・Formula (3) 1.5 ≦ N Ｓｉ・Ａ / N Ｓｉ・Ｂ ≦ 10.0 ・・・Formula (4) Here, in the above formulas (3) and (4), N Ｚｒ・Ａ : Average Zr concentration (mass%) of the phase A N Ｚｒ・Ｂ : Average Zr concentration of the phase B (mass%) N Ｓｉ・Ａ : Average Si concentration of the phase A (mass%) N Ｓｉ・Ｂ : Average Si concentration of the phase B (mass%) is.

5. 2. The precoated metal sheet according to claim 1, wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.

00.

6. The precoated metal sheet according to claim 1 , wherein the resin is at least one of a urethane-based resin, a polyester-based resin, and an acrylic-based resin.

7. The precoated metal sheet according to claim 1, further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer.

8. the coating layer further contains particles containing at least any one element of Si, V, P, Mg, Ca, or Cr, and O, and having an average particle size of 0.5 to 7.0 μm; The precoated metal sheet according to claim 1, wherein the content of the particles is 2.0 mass% or less in terms of Si, V, P, Mg, Ca, or Cr.

9. The hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. The precoated metal sheet according to claim 1.

10. The precoated metal sheet according to claim 1 , wherein the metal sheet is a zinc-based plated steel sheet having a zinc-based plating layer on at least one surface of the steel sheet.

11. The precoated metal sheet according to claim 10, wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg.

12. A member having a predetermined shape, The member is a metal plate as a substrate; a coating layer located on at least one surface of the metal plate, the coating layer containing a resin, a Zr compound, and a Si compound; an upper coating layer located on the coating layer; It is composed of, and In a 1 cm x 1 cm area of ​​the member, The coating layer has an average thickness of 0.5 to 15.0 μm, The upper coating layer has an average thickness of 5.0 to 30.0 μm, A member having a portion where the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, and the nanoindenter hardness is 0.36 GPa or more.

13. a metal plate as a substrate; a coating layer located on at least one surface of the metal plate; and the coating layer contains a resin, a Zr compound, and a Si compound; The coating layer has an average thickness of 0.5 to 15.0 μm, A surface-treated metal sheet, wherein when the hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer with a nanoindenter, there is a portion where the nanoindenter hardness is 0.36 GPa or more.

14. The surface-treated metal sheet according to claim 13, wherein the content of the Zr compound in the coating layer is 0.5 to 10.0 mass% in terms of Zr.

15. the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The surface-treated metal sheet according to claim 14, wherein the coating layer contains at least two phases, Phase A and Phase B, which satisfy the following formulas (1) and (2): H ＩＴ・Ｂ <H ＩＴ・Ａ Formula (1) 1.1 ≦ H ＩＴ・Ａ / H ＩＴ・Ｂ < 2.0 ・・・Formula (2) Here, in the above formula (1) and formula (2), H ＩＴ・Ａ : Average nanoindenter hardness of the phase A H ＩＴ・Ｂ : Average nanoindenter hardness of the phase B is.

16. the content of the Zr compound in the coating layer is 3.0% by mass or more in terms of Zr, The phase A and the phase B of the coating layer satisfy the following formulas (3) and (4), The surface-treated metal sheet according to claim 15, wherein when a cross section of the coating layer cut in the thickness direction is observed with a scanning electron microscope, the average area ratio of the phase A is 20 to 70%. 1.5 ≦ N Ｚｒ・Ａ / N Ｚｒ・Ｂ ≦ 6.0 ・・・Formula (3) 1.5 ≦ N Ｓｉ・Ａ / N Ｓｉ・Ｂ ≦ 10.0 ・・・Formula (4) Here, in the above formulas (3) and (4), N Ｚｒ・Ａ : Average Zr concentration (mass%) of the phase A N Ｚｒ・Ｂ : Average Zr concentration of the phase B (mass%) N Ｓｉ・Ａ : Average Si concentration of the phase A (mass%) N Ｓｉ・Ｂ : Average Si concentration of the phase B (mass%) is.

17. The surface-treated metal sheet according to claim 13, wherein the ratio of the Si content to the Zr compound content in the coating layer ([Si] / [Zr]) is 1.00 to 30.

00.

18. The surface-treated metal sheet according to claim 13 , wherein the resin is at least one of a urethane-based resin, a polyester-based resin, and an acrylic-based resin.

19. The surface-treated metal sheet according to claim 13, further comprising an undercoat coating layer having an average thickness of 0.05 to 2.00 μm between the metal sheet and the coating layer.

20. the coating layer further contains particles containing at least any one element of Si, V, P, Mg, Ca, or Cr, and O, and having an average particle size of 0.5 to 7.0 μm; The surface-treated metal sheet according to claim 13, wherein the content of the particles is 2.0 mass% or less in terms of Si, V, P, Mg, Ca, or Cr.

21. The hardness of the coating layer is measured by pressing an indenter into a cross section of the coating layer using a nanoindenter, and the average nanoindenter hardness is 0.31 to 0.80 GPa. The surface-treated metal sheet according to claim 13.

22. The surface-treated metal sheet according to claim 13, wherein the metal sheet is a Zn-based plated steel sheet having a Zn-based plating layer on at least one surface of the steel sheet.

23. The surface-treated metal sheet according to claim 22, wherein the Zn-based plating layer is a Zn-Al-Mg-based plating layer containing Zn, Al, and Mg.

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