Pre-coated plated steel sheet

Abstract

To achieve further improvement of scratch resistance while keeping workability.SOLUTION: A precoat plated steel sheet includes a plated steel sheet having a plating layer on a surface of the steel sheet, and a colored film layer positioned on the plating layer, wherein the plating layer has Vickers hardness of 100-800 Hv, thickness of the colored film layer is 1-10 μm, and the colored film layer contains a film-forming component having a glass transition point Tg of 30°C or higher, and resin particles.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a precoated plated steel sheet. [Background technology]

[0002] Organic resin-coated plated steel sheets (also called pre-coated steel sheets) in which an organic resin film is coated on the surface of a zinc-based plated steel sheet have come to be used for home appliances, building materials, automobiles, etc., in place of post-painted products that were conventionally painted after forming. These pre-coated steel sheets are made by coating a colored organic film on a steel sheet or plated steel sheet that has been subjected to rust prevention treatment, and have the characteristics of being beautiful, having workability, and having good corrosion resistance. These organic resin-coated plated steel sheets are often used as materials for home appliances, building materials, automobiles, etc., without being further painted after being pressed. Therefore, such organic resin-coated plated steel sheets are required to have excellent scratch resistance so as not to lose their beauty during processing. Therefore, various techniques have been proposed in the past to improve various properties, including the scratch resistance, of pre-coated steel sheets.

[0003] For example, Patent Document 1 listed below proposes a technique of providing a colored coating film containing two types of particles having a predetermined average particle size and a color pigment on at least one surface of a metal sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-121020 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in the above Patent Document 1 obtains scratch resistance as indicated by a predetermined pencil hardness by incorporating spherical silica particles with an average particle size of 5 to 50 nm into a colored coating having a thickness of 2 to 10 μm, but the resistance to scratches caused by contact with harder substances such as metals is insufficient, and there is still room for improvement.

[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 pre-coated plated steel sheet that can achieve further improvement in scratch resistance while maintaining workability. [Means for solving the problem]

[0007] In order to solve the above problems, the inventors conducted intensive research and came up with the idea that it may be possible to further improve scratch resistance by setting the hardness of the plating used in the precoated plated steel sheet within an appropriate range and setting the softening temperature of the coating within an appropriate range, which led to the completion of the present invention. The gist of the present invention, which was completed based on this concept, is as follows.

[0008] (1) A plated steel sheet having a plating layer on a surface of the steel sheet, and a colored film layer located on the plating layer, wherein the plating layer has a Vickers hardness of 100 to 800 Hv, the colored film layer has a thickness of 1 to 10 μm, and the colored film layer contains a film-forming component having a glass transition temperature Tg of 30° C. or higher and resin particles. The colored coating layer has a Vickers hardness of 10 to 70 Hv, measured at a depth of 3 / 4 of the coating thickness from the surface layer. , pre-coated galvanized steel sheet. (2) The precoated plated steel sheet according to (1), wherein the colored coating layer contains, as the film-forming component, the same type of resin as the resin that is the material of the resin particles. (3) A precoated plated steel sheet comprising: a plated steel sheet having a plating layer on a surface of the steel sheet; and a colored coating layer located on the plating layer, wherein the plating layer has a Vickers hardness of 100 to 800 Hv, the colored coating layer has a thickness of 1 to 10 μm, and the colored coating layer contains a film-forming component having a glass transition point Tg of 30° C. or higher and resin particles, and the colored coating layer contains, as the film-forming component, the same type of resin as the resin that is the material of the resin particles. (4) The colored coating layer has a Vickers hardness of 10 to 70 Hv, measured at a penetration depth of three-quarters of the coating thickness from the surface layer. (3) The precoated plated steel sheet according to claim 1. ( 5 (1) the content of the resin particles in the colored coating layer is 5 to 50% by mass based on the total content of the film-forming component and the resin particles; Any one of ~(4)The precoated plated steel sheet according to claim 1. ( 6 The average particle size of the resin particles is 1 to 15 μm. (1) Any one of ~(5) The precoated plated steel sheet according to claim 1. ( 7 ) the resin particles are acrylic resin particles, and the film-forming component is an acrylic resin; (1) to ( 6 ) The precoated plated steel sheet according to any one of the above. ( 8 ) The plated steel sheet is a zinc-based plated steel sheet, 7 ) The precoated plated steel sheet according to any one of the above. ( 9 ) The plating layer contains Al: 4 to 22 mass%, Mg: 1 to 10 mass%, Si: 0.0001 to 2.0000 mass%, and the remainder is Zn and impurities. 8 ) The precoated plated steel sheet according to any one of the above. ( 10 The coating weight of the plating layer is 30 to 600 g / m in total on both sides of the steel sheet. 2 ( 8 ) or ( 9 ) The precoated plated steel sheet according to claim 1. ( 11 ) The colored coating layer contains at least one of aluminum pigment, carbon black, and TiO2 as a color pigment, (1) to ( 10 ) The precoated plated steel sheet according to any one of the above. ( 12 ) The colored coating layer further contains an anti-rust pigment, 11 ) The precoated plated steel sheet according to any one of the above. ( 13 ) A chemical conversion coating layer is further provided between the plating layer and the color coating layer. 12 ) The precoated plated steel sheet according to any one of the above. Effect of the Invention

[0009] As described above, according to the present invention, it is possible to realize further improvement in scratch resistance while maintaining workability. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 1 is an explanatory diagram showing a schematic structure of a precoated plated steel sheet according to an embodiment of the present invention. [Figure 1B] FIG. 2 is an explanatory diagram showing a schematic structure of the precoated plated steel sheet according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0012] (About pre-coated plated steel sheets) Hereinafter, a precoated plated steel sheet according to an embodiment of the present invention will be described in detail with reference to Figures 1A and 1B. Figures 1A and 1B are explanatory diagrams that typically show the structure of the precoated plated steel sheet according to this embodiment.

[0013] As shown in Fig. 1A, the precoated plated steel sheet 1 according to this embodiment has a steel sheet 10 serving as a substrate, a plating layer 20 provided on the surface of the steel sheet 10, and a colored coating layer 30 located on the surface of the plating layer 20. Moreover, as shown in Fig. 1A, it is preferable that the precoated plated steel sheet 1 further has a chemical conversion coating layer 40 between the plating layer 20 and the colored coating layer 30.

[0014] Moreover, the plating layer 20, the colored coating layer 30, and the chemical conversion coating layer 40 may be provided on both sides of the steel sheet 10, as shown diagrammatically in FIG. 1B.

[0015] <About Steel Plate 10> The steel sheet used as the substrate is not particularly limited, and various steel sheets can be used depending on the mechanical strength required for the precoated plated steel sheet 1. Examples of such steel sheet 10 include various steel sheets such as Al-killed steel, extra-low carbon steel containing Ti, Nb, etc., and high-strength steel in which extra-low carbon steel further contains strengthening elements such as P, Si, Mn, etc.

[0016] Furthermore, the thickness of the steel sheet 10 according to this embodiment is not particularly limited and may be appropriately set depending on the mechanical strength required for the precoated plated steel sheet 1, and may be, for example, approximately 0.2 mm to 10.0 mm.

[0017] <Regarding plating layer 20> The plating layer 20 of the precoated plated steel sheet 1 according to this embodiment has a Vickers hardness (the test load is set according to the thickness of the plating layer) of 100 to 800 Hv as defined in JIS Z2244:2009. When the plating layer 20 has such hardness, the hardness of the colored coating layer 30 located above the plating layer 20 is influenced by the plating layer 20, resulting in better scratch resistance.

[0018] If the Vickers hardness of the plating layer 20 is less than 100 Hv, the hardness of the plating layer 20 is insufficient and the above-mentioned effects cannot be achieved. The Vickers hardness of the plating layer 20 is preferably 110 Hv or more, and more preferably 120 Hv or more.

[0019] On the other hand, if the Vickers hardness of the plating layer 20 exceeds 800 Hv, the workability is poor, which is undesirable. The Vickers hardness of the plating layer 20 is preferably 600 Hv or less, and more preferably 500 Hv or less.

[0020] The type of plating is not particularly limited as long as it can realize the above Vickers hardness. However, by using zinc-based plating, it is possible to more easily realize the above Vickers hardness. Examples of such zinc-based plating include zinc-nickel alloy plating, alloyed hot-dip galvanizing, aluminum-zinc alloy plating, zinc-aluminum-magnesium alloy plating, zinc-vanadium composite plating, and zinc-zirconium composite plating.

[0021] Among such zinc-based platings, zinc-aluminum-magnesium alloy plating is particularly preferred, and zinc-aluminum-magnesium-silicon 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, is more preferred.

[0022] [Al:4~22% by mass] By setting the Al content to 4 mass% or more and 22 mass% or less, the corrosion resistance of the precoated plated steel sheet 1 according to this embodiment is improved. If the Al content is less than 4 mass%, the corrosion resistance may decrease. The Al content is preferably 5 mass% or more. On the other hand, if the Al content exceeds 22 mass%, the effect of improving the corrosion resistance of the plating layer 20 may become saturated. The Al content is preferably 16 mass% or less.

[0023] [Mg:1~10% by mass] By setting the Mg content to 1% by mass or more and 10% by mass or less, the corrosion resistance of the precoated plated steel sheet 1 according to this embodiment is improved. If the Mg content is less than 1% by mass, the effect of improving the corrosion resistance of the precoated plated steel sheet 10 may be insufficient. The Mg content is preferably 2% by mass or more. On the other hand, if the Mg content exceeds 10% by mass, dross generation in the coating bath becomes significant, and it may become difficult to stably produce a hot-dip coated steel sheet. The Mg content is preferably 5% by mass or less.

[0024] [Si:0.0001~2.0000% by mass] By setting the Si content to 0.0001 mass% or more and 2.0000 mass% or less, it is possible to ensure the adhesion of the plating layer 20. If the Si content exceeds 2.0000 mass%, the effect of improving the adhesion of the plating layer 20 may become saturated. The Si content is more preferably 1.6000 mass% or less.

[0025] Furthermore, the plating layer 20 according to this embodiment may contain elements such as Fe, Sb, and Pb, either singly or in combination, in an amount of 1 mass % or less, in place of a portion of the remaining Zn.

[0026] An example of a plated steel sheet having a plating layer 20 having the above-mentioned chemical composition is a molten zinc-aluminum-magnesium-silicon alloy plated steel sheet (e.g., "Super Dima (registered trademark)" manufactured by Nippon Steel Corporation), such as a plated steel sheet having a Zn-11%Al-3%Mg-0.2%Si alloy plating layer.

[0027] The plating layer 20 according to the present embodiment as described above can be manufactured, for example, as follows. First, pretreatment such as cleaning and degreasing is performed on the surface of the prepared steel sheet 10 as necessary. Thereafter, the steel sheet which has been pretreated as necessary is immersed in a hot-dip plating bath having the desired chemical composition, and the steel sheet is pulled up from the plating bath. In this plating operation, plating may be performed by either a continuous coil plating method or a plating method for a single cut sheet.

[0028] The temperature of the hot dip plating bath varies depending on the composition, but is preferably in the range of 400 to 500°C, for example.

[0029] The coating weight of the above-mentioned coating can be controlled by adjusting the lifting speed of the steel sheet, the flow rate and flow rate of the wiping gas ejected from the wiping nozzle installed above the coating bath, etc. The coating weight is 30 to 600 g / m2 in total on both sides of the steel sheet. 2 (i.e., 15 to 300 g / m per side) 2The coating weight is preferably 30 g / m 2 If the coating weight is less than 600g / m, the corrosion resistance will decrease, which is not preferable. 2 If the coating weight exceeds 400g / m2, the molten metal adhering to the steel sheet will drip, making it impossible to smooth the surface of the hot-dip coating layer, which is not preferable. By providing the coating layer 20 with the above coating weight, it is possible to more reliably achieve the above Vickers hardness. The coating weight of the coating layer 20 is more preferably 40 to 550g / m2 in total on both sides of the steel sheet. 2 After adjusting the coating weight of the hot-dip coating layer, the steel sheet is cooled. At this time, the cooling conditions are not particularly limited.

[0030] <About the colored film layer 30> The colored coating layer 30 is a coating layer colored to a desired color by containing a color pigment. As shown in FIG. 1A and FIG. 1B, the colored coating layer 30 contains a film-forming component 301 having a glass transition temperature Tg of 30° C. or higher, and resin particles 303. The film-forming component 301 having the above-mentioned glass transition temperature Tg gives the colored coating layer 30 an appropriate hardness, and the scratch resistance (particularly, scratch resistance) of the precoated plated steel sheet 1 can be improved. Furthermore, the colored coating layer 30 contains the resin particles 303, and the toughness and ductility of the resin particles 303 can reduce impacts applied to the colored coating layer 30, thereby improving the scratch resistance (particularly, scratch resistance) of the colored coating layer 30. Furthermore, even if the colored coating layer 30 is scratched, the scratch can be prevented from reaching the plating layer 20, making it possible to maintain the corrosion resistance of the pre-coated plated steel sheet 1.

[0031] If the glass transition point Tg of the film-forming component 301 is less than 30°C, the colored film layer 30 will have insufficient hardness and will not be able to exhibit the desired scratch resistance. The glass transition point Tg of the film-forming component 301 is preferably 35°C or higher, more preferably 40°C or higher. On the other hand, the upper limit of the glass transition point Tg is not particularly specified, but if it exceeds 70°C, the processability may decrease. Therefore, the glass transition point Tg of the film-forming component 301 is preferably 70°C or lower. The glass transition point Tg can be determined, for example, by a method in which a needle is inserted from the surface of the film to be measured in the direction of the film thickness by TMA (thermomechanical analysis), a constant temperature change is applied, and the thermal expansion change of the measurement object is measured, or a method in which a constant temperature change is applied while applying a periodic deformation to the film to be measured peeled off from the substrate by DMA (dynamic viscoelasticity measurement), and viscoelasticity is analyzed.

[0032] The resin particles 303 are particulate substances produced by using an organic resin as a material. As mentioned above, when the colored coating layer 30 contains the resin particles 303, the toughness and ductility of the resin particles 303 can mitigate impacts applied to the colored coating layer 30. Furthermore, even if the colored coating layer 30 is scratched, the scratch can be prevented from reaching the plating layer 20.

[0033] In the precoated plated steel sheet 1 according to this embodiment, the thickness of the colored coating layer 30 is 1 to 10 μm. If the thickness of the colored coating layer 30 is less than 1 μm, the desired scratch resistance cannot be achieved. The thickness of the colored coating layer 30 is preferably 2 μm or more, and more preferably 3 μm or more. On the other hand, if the thickness of the colored coating layer 30 exceeds 10 μm, it is costly and coating defects such as popping may occur, making it difficult to obtain a stable appearance. The thickness of the colored coating layer 30 is preferably 8 μm or less, and more preferably 7 μm or less.

[0034] The thickness of the colored coating layer 30 can be measured by observing the cross section of the coating or by using an electromagnetic coating thickness meter. Alternatively, the thickness may be calculated by dividing the mass of the coating attached per unit area by the specific gravity of the coating or the specific gravity of the composition after drying. When measuring the thickness by observing the cross section, the thickness is measured at any number of positions (e.g., 10 positions), and the average value of the thicknesses obtained is taken as the thickness of the colored coating layer 30.

[0035] The colored coating layer 30 preferably has a Vickers hardness of 10 to 70 Hv measured at a depth of 3 / 4 of the coating thickness from the surface (the test load is set according to the hardness of the colored coating layer 30 so as to achieve a desired depth of penetration). The Vickers hardness is measured using a Universal Hardness Tester (manufactured by Fisher Instruments). The hardness is measured from the coating surface at any 10 points under the above-mentioned depth of penetration, regardless of whether the resin particles 303 are present or not, and the average of the 10 measured values ​​is calculated. The colored coating layer 30 has the above-mentioned Vickers hardness, which makes it possible to further improve the scratch resistance. The Vickers hardness of the colored coating layer 30 is more preferably 15 to 65 Hv.

[0036] In the colored coating layer 30 according to this embodiment, the content of the resin particles 303 is preferably 5 to 50 mass % based on the total content of the film-forming component 301 and the resin particles 303. When the content of the resin particles 303 is within the above range, it becomes easier to achieve the above-mentioned Vickers hardness and it becomes possible to further improve the scratch resistance. The content of the resin particles 303 in the colored coating layer 30 is more preferably 10 to 45 mass %.

[0037] In the colored coating layer 30 according to this embodiment, the film-forming component 301 that functions as a binder for the resin particles 303 is preferably the same type of resin as the resin that is the material of the resin particles 303. By using such a film-forming component 301, it is possible to further improve the affinity between the film-forming component 301 and the resin particles 303, and it is possible to further improve the scratch resistance of the colored coating layer 30.

[0038] In addition, the resin that is the material of the resin particles 303 is not particularly limited, and particles made of various organic resins can be used, but it is preferable to use resin particles made of an acrylic resin. By using such acrylic resin particles as the resin particles 303, it becomes easier to achieve the above-mentioned Vickers hardness at a lower cost.

[0039] It is also possible to use inorganic particles made of inorganic compounds such as silica and ceramics instead of the resin particles 303. However, since the inorganic particles are fragile particles, the effect of using the resin particles 303 as described above cannot be obtained.

[0040] In this embodiment, the average particle size of the resin particles 303 is preferably 1 to 15 μm. When the resin particles 303 have the above-mentioned average particle size, it is possible to further improve the scratch resistance of the precoated plated steel sheet.

[0041] Here, the average particle size refers to the particle size that is 50% by mass from the smallest particle size in the cumulative particle size distribution curve, and can be measured by known measurement methods such as dynamic light scattering and laser diffraction. The average particle size of the resin particles 303 already embedded in the colored coating layer 30 can be measured, for example, by direct observation from the cross section. There is no particular limitation on the method of cross section observation, but a method in which a coated metal plate is embedded perpendicular to the coating thickness direction in a room temperature drying type epoxy resin, the embedded surface is mechanically polished, and then observed with a SEM (scanning electron microscope), or a method in which a specimen for observation with a thickness of 50 nm to 100 nm is cut out from the coated metal plate using a FIB (focused ion beam) device so that the vertical cross section of the coating can be seen, and the coating cross section is observed with a TEM (transmission electron microscope), etc. can be used.

[0042] The color pigment contained in the color coating layer 30 is not particularly limited, and various known pigments can be used appropriately depending on the color tone desired for the color coating layer 30. Examples of such color pigments include aluminum pigments, carbon black, TiO2, etc. The content of the pigment may be appropriately set, for example, about 3 to 60 mass%.

[0043] The colored coating layer 30 can be formed by applying a coating composition containing the components constituting the colored coating layer 30 as described above, baking the coating at a temperature of 150° C. or higher and lower than 300° C., and then curing and drying the coating. If the baking temperature is lower than 150° C., the baking hardening may be insufficient, and the corrosion resistance and scratch resistance of the coating may decrease, whereas if the baking temperature is 300° C. or higher, thermal degradation of the resin components may occur, and processability may decrease.

[0044] The coating composition as described above can be applied by a generally known coating method, such as roll coating, curtain flow coating, air spray, airless spray, dipping, bar coating, brush coating, or the like.

[0045] Furthermore, the colored coating layer 30 may further contain additives such as anti-rust pigments, surface-modified metal powders or glass powders, dispersants, leveling agents, waxes, aggregates, and dilution solvents, as necessary, within the scope that does not impair the above-mentioned effects.

[0046] When the anti-rust pigment is contained, the content is preferably, for example, 1 to 15 mass %. The anti-rust pigment used is not particularly limited, and various known anti-rust pigments can be used.

[0047] <About the chemical conversion coating layer 40> The chemical conversion coating layer 40 in this embodiment is a coating layer that can be located between the plating layer 20 and the colored coating layer 30, and is a layer that is formed by chemical conversion treatment after impurities such as oil and surface oxides adhering to the surface of the plating layer 20 are removed by known degreasing and cleaning processes.

[0048] The detailed composition of the chemical conversion coating layer 40 according to this embodiment is not particularly limited, and may contain one or more selected from the group consisting of resin, silane coupling agent, zirconium compound, silica, phosphoric acid and its salt, fluoride, vanadium compound, and tannin or tannic acid. The inclusion of these substances further improves the film-forming properties after application of the chemical conversion coating solution, the barrier properties (density) of the coating against corrosive factors such as moisture and corrosive ions, and the coating adhesion to the plating surface, thereby contributing to raising the corrosion resistance of the coating.

[0049] In particular, when the chemical conversion coating layer 40 contains one or more of a silane coupling agent or a zirconium compound, a cross-linked structure is formed within the coating layer 40, and the bond with the plating surface is also strengthened, making it possible to further improve the adhesion and barrier properties of the coating.

[0050] Furthermore, when the chemical conversion coating layer 40 contains one or more of silica, phosphoric acid and its salts, fluorides, and vanadium compounds, these function as inhibitors and form a precipitate film or a passivation film on the plating or steel surface, thereby making it possible to further improve corrosion resistance.

[0051] In the following, the components that may be contained in the chemical conversion coating layer 40 as described above will be described in detail with reference to examples.

[0052] [resin] The resin is not particularly limited, and known organic resins such as polyester resin, polyurethane resin, epoxy resin, phenol resin, acrylic resin, polyolefin resin, etc. can be used. For precoated plated steel sheet, in order to further increase adhesion to plated steel sheet, it is preferable to use at least one resin having a forced site or a polar functional group in the molecular chain (polyester resin, urethane resin, epoxy resin, acrylic resin, etc.). The resin may be used alone or in combination of two or more kinds.

[0053] The resin content in the chemical conversion coating layer 40 is preferably, for example, 0% by mass or more and 85% by mass or less relative to the coating solid content. The resin content is more preferably 0% by mass or more and 60% by mass or less, and even more preferably 1% by mass or more and 40% by mass or less. If the resin content exceeds 85% by mass, the proportions of other coating constituent components decrease, and performance required of the coating other than corrosion resistance may decrease.

[0054] [Silane coupling agents] Examples of the silane coupling agent include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxy ...triethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysil Dipropylmethyldiethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxy Silane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane, gamma-chloropropyltrimethoxysilane, gamma-chloropropylmethyldimethoxysilane, gamma-chloropropyltriethoxysilane, gamma-chloropropyl dimethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropylmethyldiethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldimethoxysilyl)propyl]ammonium chloride,Examples of suitable silane coupling agents include octadecyldimethyl[3-(triethoxysilyl)propyl]ammonium chloride, octadecyldimethyl[3-(methyldiethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane. The amount of silane coupling agent added to the chemical conversion coating layer 40 can be, for example, 2 to 80 g / L. If the amount of silane coupling agent added is less than 2 g / L, the adhesion to the plating surface may be insufficient, and the processing adhesion of the coating film may decrease. If the amount of silane coupling agent added is more than 80 g / L, the cohesive force of the chemical conversion coating layer may be insufficient, and the processing adhesion of the coating film layer may decrease. The silane coupling agents exemplified above may be used alone or in combination of two or more.

[0055] [Zirconium compounds] Examples of the zirconium compound include zirconium normal propylate, zirconium normal butylate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium monoethylacetoacetate, zirconium acetylacetonate bisethylacetoacetate, zirconium acetate, zirconium monostearate, zirconium carbonate, zirconium ammonium carbonate, zirconium potassium carbonate, and zirconium sodium carbonate. The amount of the zirconium compound added to the chemical conversion coating layer 40 can be, for example, 2 to 80 g / L. If the amount of the zirconium compound added is less than 2 g / L, the adhesion to the plating surface may be insufficient, and the processing adhesion of the coating layer may be reduced. If the amount of the zirconium compound added is more than 80 g / L, the cohesive force of the chemical conversion coating layer may be insufficient, and the processing adhesion of the coating layer may be reduced. Such zirconium compounds may be used alone or in combination of two or more kinds.

[0056] [silica] As the silica, for example, commercially available silica gel such as "Snowtex N", "Snowtex C", "Snowtex UP", and "Snowtex PS" manufactured by Nissan Chemical Industries, Ltd., "Adelite AT-20Q" manufactured by ADEKA Corporation, or powdered silica such as Aerosil #300 manufactured by Nippon Aerosil Co., Ltd. can be used. The silica can be appropriately selected according to the required performance of the precoated plated steel sheet. The amount of silica added in the chemical conversion treatment agent for forming the chemical conversion treatment film layer 40 is preferably 1 to 40 g / L. If the amount of silica added is less than 1 g / L, the processing adhesion of the film layer may decrease, and if the amount of silica added is more than 40 g / L, the effects of processing adhesion and corrosion resistance are likely to be saturated, which is uneconomical.

[0057] [Phosphoric acid and its salts] Examples of phosphoric acid and its salts include phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid, and their salts, ammonium salts such as triammonium phosphate and diammonium hydrogen phosphate, phosphonic acids such as aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), and diethylenetriaminepenta(methylenephosphonic acid), and their salts, and organic phosphoric acids such as phytic acid and their salts. Examples of phosphoric acid salts other than ammonium salts include metal salts with Na, Mg, Al, K, Ca, Mn, Ni, Zn, Fe, and the like. Phosphoric acid and its salts may be used alone or in combination of two or more.

[0058] The content of phosphoric acid and its salts is preferably 0% by mass or more and 20% by mass or less based on the solid content of the coating. If the content of phosphoric acid and its salts exceeds 20% by mass, the coating becomes brittle and the processing followability of the coating may decrease when the precoated plated steel sheet is formed. The content of phosphoric acid and its salts is more preferably 1% by mass or more and 10% by mass or less.

[0059] [Fluoride] Examples of the fluoride include ammonium zirconate fluoride, ammonium silicofluoride, ammonium titanium fluoride, sodium fluoride, potassium fluoride, calcium fluoride, lithium fluoride, titanium hydrofluoric acid, zirconate hydrofluoric acid, etc. Such fluorides may be used alone or in combination of two or more.

[0060] The fluoride content is preferably 0% by mass or more and 20% by mass or less based on the solid content of the coating. If the fluoride content exceeds 20% by mass, the coating becomes brittle and the processing followability of the coating may decrease when the precoated plated steel sheet is formed. The fluoride content is more preferably 1% by mass or more and 10% by mass or less.

[0061] [Vanadium compounds] Examples of vanadium compounds include vanadium compounds obtained by reducing pentavalent vanadium compounds such as vanadium pentoxide, metavanadic acid, ammonium metavanadate, sodium metavanadate, and vanadium oxytrichloride to divalent to tetravalent vanadium compounds with a reducing agent, vanadium trioxide, vanadium dioxide, vanadium oxysulfate, vanadium oxyoxalate, vanadium oxyacetylacetonate, vanadium acetylacetonate, vanadium trichloride, phosphovanadomolybdic acid, vanadium sulfate, vanadium dichloride, and vanadium oxide, and other vanadium compounds having an oxidation number of 4 to 2. Such vanadium compounds may be used alone or in combination of two or more.

[0062] The content of the vanadium compound is preferably 0% by mass or more and 20% by mass or less based on the solid content of the coating. If the content of the vanadium compound exceeds 20% by mass, the coating becomes brittle and the processing followability of the coating may decrease when the precoated plated steel sheet is formed. The content of the vanadium compound is more preferably 1% by mass or more and 10% by mass or less.

[0063] [Tannin or tannic acid] Tannin or tannic acid may be either hydrolyzable tannin or condensed tannin. Examples of tannin and tannic acid include hammeta tannin, Chinese gall tannin, gall tannin, myrobalan tannin, dividivi tannin, algarovila tannin, valonia tannin, and catechin. The amount of tannin or tannic acid added to the chemical conversion coating 40 may be 2 to 80 g / L. If the amount of tannin or tannic acid added is less than 2 g / L, the adhesion to the plating surface may be insufficient, and the processing adhesion of the coating may be reduced. If the amount of tannin or tannic acid added is more than 80 g / L, the cohesive force of the chemical conversion coating may be insufficient, and the processing adhesion of the coating may be reduced.

[0064] Furthermore, an acid, an alkali, or the like may be added to the chemical conversion treatment agent used to form the chemical conversion coating 40 in order to adjust the pH, within a range that does not impair performance.

[0065] The chemical conversion treatment agent containing the above-mentioned various components is applied to one or both sides of the plating layer 20 and then dried to form the chemical conversion coating layer 40. In the precoated plated steel sheet according to this embodiment, the chemical conversion treatment agent is applied to one or both sides of the plating layer 20 in an amount of 10 to 1000 mg / m2 per side. 2 It is preferable to form the chemical conversion coating layer 40 on the plating layer 20. The coating weight of the chemical conversion coating layer 40 is more preferably 20 to 800 mg / m 2 and most preferably 50 to 600 mg / m 2 The film thickness of the chemical conversion coating layer 40 corresponding to this amount of adhesion will vary depending on the components contained in the chemical conversion treatment agent, but will generally be about 0.01 to 1 μm.

[0066] The colored coating layer 30 and the chemical conversion coating layer 40 according to this embodiment have been described above with reference to the paint composition and chemical conversion coating agent used to form the respective films. Usually, when these treatment agents and compositions are applied to a plated steel sheet, the components of these treatment agents and the component composition of the coating formed are usually different. For example, in the case of a chemical conversion coating agent, the composition of the chemical conversion coating agent and the chemical conversion coating film after application differ due to reaction with the plated steel sheet, volatilization of volatile components in the chemical conversion coating agent, etc., and it is usually technically difficult to specify the composition of the formed chemical conversion coating layer. In addition, it is technically difficult in reality to specify the composition of such a chemical conversion coating layer by instrumental analysis, etc. This is also true for the colored coating layer. Therefore, in this embodiment, the colored coating layer 30 and the chemical conversion coating layer 40 formed are specified by specifying the composition of the paint composition and the chemical conversion coating agent. EXAMPLES

[0067] The precoated plated steel sheet according to the present invention will be specifically described below with reference to examples and comparative examples. Note that the examples shown below are merely examples of the precoated plated steel sheet according to the present invention, and the precoated plated steel sheet according to the present invention is not limited to the following examples.

[0068] (1) Galvanized steel sheet Eleven types of metal sheets, A1 to A11, shown in Table 1 below, were prepared. Steel sheets with a thickness of 0.7 mm were used as the substrates for the plated metal sheets. Furthermore, chromate-free conversion coating (CT-E300 / Nihon Parkerizing Co., Ltd.) was applied to these metal sheets at a concentration of 60 mg / m 2 The plating steel sheets were also prepared. The treatment solution used for the chemical conversion treatment contained a silane coupling agent as a component, and the coating layer formed by the chemical conversion treatment functions as a chemical conversion coating layer. The presence or absence of chemical conversion treatment is shown in Table 6 below.

[0069] [Table 1]

[0070] (2) Adjustment of colored paint A colored coating material for forming a colored coating layer was prepared. The resins shown in Table 2 below were prepared as binder resins. A melamine-based hardener was added to each resin solution as a hardener at a solid content ratio of 15 mass %. Furthermore, the particles shown in Table 3 below were prepared and added at the specified particle size and amount shown in Table 6 below. Furthermore, the aluminum pigment, titanium oxide, and carbon black (CB) shown in Table 4 below were prepared as color pigments and added at the specified amounts shown in Table 6 below. Furthermore, the compounds shown in Table 5 below were prepared as rust-preventive pigments and added at the specified amounts shown in Table 6 below to prepare colored paints.

[0071] [Table 2]

[0072] [Table 3]

[0073] [Table 4]

[0074] [Table 5]

[0075] (3) Sample preparation The colored coating material prepared as described above was applied to a plated steel sheet using a bar coater so that the dry film thickness was as shown in Table 6 below, and the sheet was heated to a maximum reached sheet temperature (PMT) of 200°C in 60 seconds to form a colored coating layer.

[0076] [Table 6]

[0077] (4) Evaluation of samples The performance of each sample prepared by the above method was evaluated based on the following criteria. The evaluation results are shown in Table 7 below.

[0078] <Appearance> The appearance of the prepared samples was evaluated according to the following criteria, with a score of 2 or more being considered pass and a score of 1 being considered fail. Evaluation criteria 3: The coating has a uniform colored appearance. 2: The appearance of the colored film is slightly uneven. 1: The appearance of the colored film is uneven due to the occurrence of popping etc.

[0079] <Scratch resistance> Scratch resistance was evaluated using the coin scratch test described below. A coin was placed in contact with the coating surface of the sample at a 45 degree angle and the load was changed to 100g, 500g, and 1000g to scratch the surface. The scratches made at each load were evaluated according to the following criteria, and a rating of 2 or higher at all loads was deemed to be a pass. Evaluation criteria 5: No peeling of the coating or change in gloss was observed. 4: No peeling of the coating is observed, but slight changes in gloss are observed. 3: Slight peeling of the coating film and change in gloss are observed. 2: Partial peeling of the coating is observed, and changes in gloss are observed. 1: The coating has completely peeled off.

[0080] <Workability> The workability was evaluated based on the following criteria. The prepared samples were bent 180 degrees with the painted surface facing outward, and the outer side of the bent part was evaluated based on the following criteria. The bending was performed in an atmosphere of 20°C, with a 0.7mm spacer between the samples. A score of 2 or more was considered a pass, and a score of 1 was considered a fail. Evaluation criteria 5: No cracks are observed in the coating. 4: Very slight cracks are observed in the coating. 3: Slight cracks are observed in the coating. 2: Cracks are observed in the coating. 1: Significant cracks are observed throughout the coating.

[0081] <Corrosion resistance> As a reference performance, the corrosion resistance was evaluated based on the following criteria: After sealing the edges of the test plate with tape, a salt spray test (SST) in accordance with JIS Z 2371 was carried out for 72 hours, and the occurrence of rust was observed and evaluated based on the following criteria. Evaluation criteria 4: Rust area is less than 1%. 3: Rust area is 1% or more but less than 3% 2: Rust area is 3% or more but less than 5% 1: Rust area is 5% or more

[0082] [Table 7]

[0083] As is clear from Table 7 above, the pre-coated steel sheets corresponding to the examples of the present invention have excellent appearance, scratch resistance, and workability, while the pre-coated steel sheets corresponding to the comparative examples of the present invention are inferior in any one of appearance, scratch resistance, or workability.

[0084] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0085] 1 Pre-coated plated steel sheet 10 steel plate 20 Plating layer 30 Colored film layer 40 Chemical conversion coating layer 301 Film-forming ingredients 303 resin particles

Claims

1. A plated steel sheet having a plating layer on a surface of the steel sheet; a colored coating layer located on the plating layer; Equipped with The plating layer has a Vickers hardness of 100 to 800 Hv; The thickness of the colored coating layer is 1 to 10 μm, The colored coating layer contains a film-forming component having a glass transition temperature Tg of 30° C. or higher and resin particles, The colored coating layer has a Vickers hardness of 10 to 70 Hv as measured at an indentation depth of three-quarters of the coating thickness from the surface layer.

2. A pre-coated plated steel sheet as described in claim 1, wherein the colored coating layer contains, as the film-forming component, a resin of the same type as the resin that is the material of the resin particles.

3. A plated steel sheet having a plating layer on a surface of the steel sheet; a colored coating layer located on the plating layer; Equipped with The plating layer has a Vickers hardness of 100 to 800 Hv; The thickness of the colored coating layer is 1 to 10 μm, The colored coating layer contains a film-forming component having a glass transition temperature Tg of 30° C. or higher and resin particles, The colored coating layer contains, as the film-forming component, the same type of resin as the resin that is the material of the resin particles.

4. 4. The precoated plated steel sheet according to claim 3, wherein the colored coating layer has a Vickers hardness of 10 to 70 Hv as measured at an indentation depth of three-quarters of the coating thickness from the surface layer.

5. The precoated plated steel sheet according to any one of claims 1 to 4, wherein the content of the resin particles in the colored coating layer is 5 to 50 mass% with respect to the total content of the film-forming component and the resin particles.

6. The precoated plated steel sheet according to any one of claims 1 to 5, wherein the resin particles have an average particle size of 1 to 15 µm.

7. The precoated plated steel sheet according to any one of claims 1 to 6, wherein the resin particles are acrylic resin particles, and the film-forming component is an acrylic resin.

8. The precoated plated steel sheet according to any one of claims 1 to 7, wherein the plated steel sheet is a zinc-based plated steel sheet.

9. The precoated plated steel sheet according to any one of claims 1 to 8, wherein the plating layer contains 4 to 22 mass% Al, 1 to 10 mass% Mg, 0.0001 to 2.0000 mass% Si, with the balance being Zn and impurities.

10. The coating weight of the plating layer is 30 to 600 g / m in total on both sides of the steel sheet. ２ The precoated plated steel sheet according to claim 8 or 9,

11. The colored coating layer contains aluminum pigment, carbon black, or TiO as a color pigment. ２ The precoated plated steel sheet according to any one of claims 1 to 10, comprising at least one of the following:

12. The precoated plated steel sheet according to any one of claims 1 to 11, wherein the colored coating layer further contains an anti-rust pigment.

13. The precoated plated steel sheet according to any one of claims 1 to 12, further comprising a chemical conversion coating layer between the plating layer and the color coating layer.

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