TWI601852B - Painting metal plate - Google Patents

Description

Painted metal plate

This invention relates to a coated metal sheet.

A stainless steel plate which has been improved in design by etching, coloring, surface treatment, or the like has been used for a door material, an operation panel, or the like of a previous elevator. For these stainless steel sheets, fingerprints and the like are required to be difficult to adhere, and high in stain resistance and scratch resistance are required. Therefore, a coating film containing a resin, a wax, an oil, or the like is usually formed on the surface of the stainless steel plate.

However, when a coating film containing a resin is formed on the surface of the stainless steel sheet, the coating film is cracked or whitened due to a change with time, and the design property is easily impaired. In addition, wax or oil must be recoated periodically.

Therefore, a coating film containing an inorganic material is being formed on the surface of a stainless steel plate (for example, Patent Document 1). A coating film containing an inorganic material has an advantage that the change with time is small and the hardness is high.

On the other hand, in recent years, the design of stainless steel sheets has been advanced, and it has been required to apply a finer pattern to the surface of the stainless steel sheets. For example, a method of improving the designability by making the polishing depth of the stainless steel plate shallow is employed. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-1685

[Problems to be Solved by the Invention] When a coating film containing an inorganic material is formed on the surface of a metal plate such as a stainless steel plate, light reflected on the surface of the metal plate and light reflected on the surface of the coating film are likely to interfere with each other. Color shift, coloring, etc. (hereinafter also referred to as "interference fringes"). Further, in particular, in a metal plate having high surface smoothness, interference fringes are likely to occur due to the large amount of light that is regularly reflected on the surface thereof and the surface of the coating film being easily parallel to the surface of the metal plate.

Regarding the method of suppressing the interference fringe, it is thought that the thickness of the coating film formed on the surface of the metal plate is increased. However, in this case, there is a problem in that it is easy to lose the texture (metal feeling, etc.) derived from the metal plate, and the design property is easily damaged. Further, in order to suppress interference fringes, it is also thought that the coating material contains an aggregate, but in this case, the transparency of the coating film is liable to lower, and the design property is easily impaired.

The present invention has been made in view of such circumstances. That is, an object of the present invention is to provide a coated metal sheet which is excellent in stain resistance, does not cause interference fringes, and is excellent in design. [Means to solve the problem]

The present invention provides the following coated metal sheets. [1] A coated metal plate having: a metal plate having an average surface roughness Ra _{(metal plate)} of 0.40 μm or less; and a coating film formed on at least one surface of the metal plate, substantially comprising a composition formula K ₂ O·xSiO ₂ (3.5≦x<6.8), the average thickness t is 0.2 μm or more and 3.0 μm or less; and the average thickness t of the coating film and the average surface roughness Ra of the coating film _{(Coating film)} satisfies the following formula (1), Ra _{(coating film)} ≧ 0.03/t+0.15 (1).

[2] The coated metal sheet according to [1], wherein the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} further satisfy the following formula (2), Ra _{( Coating film)} ≧0.08/t+0.12 (2). [Effects of the Invention]

According to the present invention, it is possible to obtain a coated metal sheet which is excellent in stain resistance, does not cause interference fringes, and is excellent in design.

The present invention relates to a coated metal sheet having: a metal plate having a relatively smooth surface, that is, a metal plate having an average surface roughness Ra _{(metal plate)} of 0.40 μm or less; and a coating film formed on the metal plate Above, and contains inorganic materials. The metal coated board can be applied, for example, to a door material or an operation panel of an elevator, an outer panel of a home appliance, furniture or daily necessities, building materials, and the like.

As described above, in order to improve the stain resistance of the metal plate, it is being studied to form a coating film containing an inorganic material on the surface of the metal plate. However, when a coating film containing an inorganic material is formed on the surface of a metal sheet having high surface smoothness, light reflected on the surface of the metal sheet easily interferes with light reflected on the surface of the coating film, and interference fringes are likely to occur. On the other hand, when the thickness of the coating film is increased to suppress interference fringes, the texture from the metal sheet is easily damaged, and the design property is liable to lower.

On the other hand, the present inventors have found that the average thickness t of the coating film formed on the surface of the metal plate and the average surface roughness Ra _{(coating film) of the coating film} satisfy a predetermined relationship, and it is difficult to produce even if the coating film is thin. The interference fringe can obtain a coated metal plate excellent in design. Specifically, when the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} satisfy the following formula (1), interference fringes are less likely to occur. Ra _{(coating film)} ≧ 0.03/t+0.15 (1) Further, the average thickness t of the coating film is 0.2 μm or more and 3.0 μm or less.

The reason why the average thickness t of the coating film and the average surface roughness Ra _{(coating film)} of the _{coating film} satisfy the formula (1) and the interference fringe is not easily generated is as follows. The thinner the thickness t of the coating film formed on the metal plate, the more easily the light reflected by the surface of the metal plate and the light reflected on the surface of the coating film interfere with each other, and the interference fringes are more likely to occur. Therefore, in the coated metal sheet of the present invention, the coating film is formed such that the surface roughness Ra _{(coating film)} of the surface of the _{coating film} becomes larger as the thickness t of the _{coating film} becomes smaller. By having a moderate unevenness on the surface of the coating film, the direction of the light reflected by the surface of the coating film or the direction of the light reflected from the surface of the metal sheet and emitted from the surface of the coating film tends to become uneven. As a result, the light reflected by the surface of the coating film and the light reflected by the surface of the metal plate are less likely to interfere, and interference fringes are less likely to occur.

Here, it is preferable that the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} further satisfy the following formula (2). When the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} satisfy the formula (2), interference fringes are less likely to occur. Ra _{(coating film)} ≧0.08/t+0.12 (2)

However, when the average surface roughness Ra _{(coating film) of the coating film is} excessively large, the glossiness of the coated metal sheet or the like may be lost, and the design property may be lowered. Therefore, the upper limit of the average surface roughness Ra _{(coating film)} of the _{coating film} is preferably 0.8 μm, more preferably 0.4 μm.

Further, the average thickness t of the coating film may be 0.2 μm or more and 3.0 μm or less, and more preferably 0.2 μm to 1.0 μm. If the average thickness t of the coating film becomes too thick, the texture derived from the metal plate in the coated metal sheet is easily damaged. On the other hand, when the average thickness t of the coating film is 3.0 μm or less, the light transmittance of the coating film is improved, and it is easy to obtain a coated metal plate having high design properties. In the case where the coating film has the average surface roughness Ra _{(coating film)} , if the average thickness t of the coating film is 0.2 μm or more, the coating film is easily formed on the surface of the metal plate without a gap, and the metal plate is coated. The corrosion resistance is likely to be good.

Further, the average surface roughness Ra _{(metal plate) of the metal plate} and the average surface roughness Ra _{(coating film) of the} surface of the _{coating film} are respectively in accordance with Japanese Industrial Standards (JIS) B0601: 2001 (International Organization for Standardization ( The value measured by International Standard Organization, ISO) 4287) can be measured by a known surface roughness measuring machine or the like. Further, the average thickness t of the coating film can be measured by arbitrarily cutting the coated metal sheet and observing the cross section. Specifically, after embedding the test piece cut from the coated metal plate with a resin, an appropriate cross section is produced by polishing or the like. Further, a highly accurate observation cross section is produced by ion milling or the like. Then, any 10 points were observed by a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and the average value of the thicknesses of 10 points was taken as the average thickness t.

In the coated metal sheet of the present invention, the coating film may be formed only on one surface of the metal sheet or on both surfaces. Further, the coating film may be formed only in a partial region of the metal plate, or may be formed in the entire region on one or both sides of the metal plate.

In addition, the average value of the coverage of the coating film per 1 mm ² of any one of the coated metal sheets having a coating film (hereinafter also referred to as "average coating film coverage") is preferably 95% or more, and particularly preferably It is formed on the metal plate without a gap. In addition, the shape of the region (1 mm ² ) in which the coating film coverage is determined is not particularly limited, and may be, for example, a rectangular shape such as a square or a rectangle, or a circular shape, and is generally rectangular. The average coating coverage was determined by the following method.

The Si element distribution was measured at any 10 (1 mm ² region) of the region where the coating film was formed by SEM (Scanning Electron Microscope)/Energy Dispersive X-Ray Spectroscopy (EDS). Then, the obtained distribution image of Si is binarized by the image processing software. At the time of binarization, a region where Si is increased (even if it is slightly) is treated as a region where the coating film is present, based on the Si detection value of the portion (metal plate) on which the coating film is not formed. Then, based on the obtained binarized image, the number of pixels of the region where Si is added (the region where the coating film is present) is divided by the total number of pixels, and the coating coverage is calculated. Then, the average value of the coating ratios of the coating films was taken as the average coating film coverage.

Here, the metal plate may have a metal plate having an average surface roughness Ra _{(metal plate)} of 0.40 μm or less, and the average surface roughness Ra _{(metal plate) is} preferably 0.05 μm to 0.35 μm. As such a metal plate, for example, stainless steel (Stainless Steel, SUS) 304, SUS316 or the like, austenite-based stainless steel or ferrite-based stainless steel such as SUS430 can be used. In the application requiring mechanical strength, it is preferable to use a material obtained by work-hardening a Worthite iron or a ferrite-based stainless steel by cold rolling, or a martensite stainless steel such as SUS410 or SUS420. A precipitation-strengthened stainless steel plate such as a plate or SUS631. Further, in addition to the stainless steel plate, copper, carbon steel, iron-nickel alloy, various plated steel sheets, and aluminum plates may be used.

The metal plates may also be metal plates that have been surface-processed according to the usual method. The metal plate may be, for example, a metal plate subjected to smooth surface finishing such as Bright Annealing (BA) finishing or mirror finishing, or may be drawn for design or functionality (Hairline, HL). ) A metal plate that is linearly polished, such as finishing. In addition, a metal plate subjected to a curved polishing process such as vibration grinding may be used, or a metal plate subjected to dot-like uneven processing may be used. Further, it may be a metal plate colored by various methods such as oxidation coloring or sputtering coloring.

On the other hand, the coating film substantially contains a composition represented by the composition formula K ₂ O·xSiO ₂ (3.5≦x<6.8), and can be made into potassium citrate (K ₂ O·nSiO ₂ (2≦n≦4). The obtained film is coated and dried with a mixture of colloidal cerium oxide (SiO ₂ ). Further, the composition formula K ₂ O·xSiO _{2 does} not indicate the state of the element in the coating film, but represents the ratio of the constituent elements. In the coating film, SiO ₂ usually forms a decane bond. On the other hand, potassium is a potassium ion and is electrically attracted to a citrate ion which does not form a siloxane coupling.

The ratio of cerium oxide (SiO ₂ ) to potassium oxide (K ₂ O) represented by x in the composition formula may be 3.5 or more and less than 6.8, and more preferably 3.8 or more and 5.2 or less. When the value represented by x is less than 3.5, potassium ions are excessively eluted on the surface of the coating film, and an efflorescence phenomenon in which eluted potassium ions react with carbon dioxide in the atmosphere to form carbonates is likely to occur. On the other hand, if the value represented by x is 6.8 or more, it is necessary to mix a large amount of colloidal cerium oxide at the time of forming a coating film. As a result, the film forming property is lowered, and sometimes there is no sufficient strength as a film. Further, the composition of the coating film can be adjusted by a mixing ratio of potassium citrate and colloidal cerium oxide. In addition, the composition of the coating film can be confirmed by EDS, X-Ray Fluorescence (XRF), Electron Probe Micro-Analysis (EPMA), etc., and X-ray photoelectrons can be used. X-ray Photoelectron Spectroscopy (XPS), Infrared Spectroscopy (IR), etc. were used to confirm the chemical bond state of Si.

In the coated metal sheet of the present invention, the coating film contains a composition represented by the composition formula K ₂ O·xSiO ₂ (3.5 ≦ x < 6.8), so that the stain resistance is high. The reason is speculated as follows. For the coating film containing the composition, potassium is eluted in a small amount on the surface. Then, potassium ions hydrate with the moisture in the atmosphere to attract moisture in the atmosphere. As a result, the entire surface of the coated metal sheet is covered with a thin water film. Therefore, even if oil stains such as sebum or oily ink adhere to the surface of the coated metal sheet, the stains are floating on the water film, and the stain can be easily removed by wiping or the like.

Further, in general, if a stain adheres to the surface of the coated metal sheet for a while, a part of the stain is impregnated into the coating film or the metal plate, and the removal of the stain becomes difficult. On the other hand, in the coated metal sheet of the present invention, since a water film having a sufficient thickness exists on the surface, it is difficult for the stain component to penetrate into the coated metal sheet. Further, since the coating film has high hydrophilicity, water easily permeates between the surface of the coated metal sheet and the stain. Therefore, the stain adhering to the surface of the coated metal sheet can be peeled off by water wiping or the like. It is considered that the hydrophilicity of the coating film is expressed by the high hydration of potassium ions eluted in a small amount on the surface of the coating film and the hydrophilicity of the stanol group.

Here, the coating film is obtained by coating a mixture of potassium citrate and colloidal cerium on a metal plate by the method described later and drying it. Further, potassium citrate and colloidal cerium oxide used to form a coating film may be common reagents or industrial chemicals. Examples of commercially available products of potassium citrate include "A potassium citrate" or "2K potassium citrate" manufactured by Nippon Chemical Industry Co., Ltd., "No. 2 potassium citrate" manufactured by Fuji Chemical Co., Ltd., and "Nissan Chemical Co., Ltd." Snowtex K2" and so on. On the other hand, examples of commercial products of colloidal cerium oxide include "Adelite AT" manufactured by ADEKA Co., Ltd. or "Snowtex" manufactured by Nissan Chemical Co., Ltd., Japan. "Silicadol" of the chemical industry company. Further, in the mixed solution for forming a coating film, a solvent, a leveling agent, an antifoaming agent, or the like may be added as needed, together with potassium citrate and colloidal cerium oxide.

The method of applying the mixed solution for forming a coating film is not limited as long as the coating film can be formed so that the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} satisfy the formula (1). . However, in the case where the mixed solution is applied to a metal plate only by a general coating method (for example, a roll coating method, a curtain flow coating method, a bar coating method, a spray method, etc.), the mixed liquid is easily leveled. It is difficult to obtain a _{coating film in which the} average thickness t and the average surface roughness Ra _{(coating film)} satisfy the formula (1).

Here, an example of a method of obtaining the coating film satisfying the above formula (1) is a method in which the mixed liquid is applied and dried several times by an atomization spray method. According to the atomization spray method, the particle size of the mixed liquid released from the spray nozzle can be controlled (atomized) smaller than that of the prior spray method, and the mixture can be inhibited from being sprayed (coated) on the steel sheet. The level of time. In addition, since the coating amount per coating can be reduced, it is easy to control (thinning) the thickness, and the number of times of coating and drying can be increased. Further, by repeatedly applying and drying a small amount of the mixed solution, the average surface roughness Ra _{(coating film) is} gradually increased to form a coating film satisfying the above formula (1).

Further, a method of reducing the amount of non-volatile components (potassium citrate and colloidal cerium oxide) in the mixed solution applied to the metal plate, and repeatedly applying and drying the mixed solution may be mentioned. When the amount of the nonvolatile component in the mixed solution is small, the component which substantially forms the coating film per coating can be reduced. Thereby, it is easy to control (thinning) the thickness, and the number of times of coating and drying can be increased. Further, by applying and drying the mixed solution in this manner, the average surface roughness Ra _{(coating film) is} gradually increased to form a coating film satisfying the above formula (1). In this case, the amount of the non-volatile component in the mixed solution is appropriately selected depending on the thickness t of the coating film or the average surface roughness Ra _{(coating film)} required, and may be, for example, less than the total amount of the mixed liquid. 4% by mass.

Further, the drying time or the drying temperature of the mixed solution is appropriately selected depending on the amount or type of the solvent contained in the mixed liquid.

In the case of the atomized spray method, the number of coatings may be adjusted according to the coating amount (spray time) of each coating, and the average thickness t or average surface roughness Ra _{(coating film) of the} target coating _film . The selection is usually preferably from 2 to 20 times, more preferably from 4 to 12 times.

An example of a method of forming the coating film by an atomization spray method is to transfer a metal plate at a slight speed by a conveyor or the like, and to reciprocate the atomizing spray gun perpendicularly to the traveling direction of the metal plate. method. According to this method, the coating film can be continuously formed with high efficiency.

Further, a method in which the mixed solution is applied by a roll coating method and then over-coating the mixed liquid by an atomization spray method may be employed. Previously, it was difficult to obtain an average surface roughness Ra _{(coating film) of} the formula (1) at a desired coating film thickness t in the case of roll coating alone, but by external coating by atomization spray method, Give surface roughness. According to this method, the coating film can be formed on the surface of the metal plate without a gap by uniform coating properties as a feature of roll coating. Therefore, according to this method, a coated metal plate having high corrosion resistance can be easily obtained. [Examples]

Hereinafter, the present invention will be described in detail with reference to the embodiments, but the invention is not limited thereto.

A coated metal plate was produced by the following method, and the contamination resistance of the surface and the presence or absence of interference fringes were confirmed for each of the coated metal plates. In addition, the metal plate is a metal plate A to a metal plate F shown in Table 1 below.

[Table 1]         <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> metal plate</td><td> steel type</td><td> surface finishing < /td></tr><tr><td> A </td><td> SUS316 </td><td> Vibration Grinding</td></tr><tr><td> B </td> <td> SUS304 </td><td> Brushed Grinding</td></tr><tr><td> C </td><td> SUS430 </td><td> Sandblasting</td></ Tr><tr><td> D </td><td> SUS316 </td><td> Vibration Grinding + Sputtering Coloring</td></tr><tr><td> E </td>< Td> SUS304 </td><td> Wire drawing + oxidation coloring</td></tr><tr><td> F </td><td> SUS304 </td><td> Matting finishing ( Keep rolling state) </td></tr></TBODY></TABLE>

[Preparation of a mixed solution] Potassium citrate (manufactured by Fuji Chemical Co., Ltd., trade name: No. 2 potassium citrate, K ₂ O·nSiO ₂ , n = 3.61) and colloidal cerium oxide (manufactured by Nippon Chemical Industry Co., Ltd., trade name) Silicadol is mixed in a mass ratio of 100:13.3 in terms of solid content to obtain a mixed solution. The concentration of the nonvolatile components (potassium citrate and colloidal cerium oxide) at this time was 3% by mass.

[Coating of Mixed Liquid] The mixed liquid was applied onto the metal plate A to the metal plate F by the method shown in Table 2 (roll coating method, spray coating method, and/or atomization spray method). In addition, the number of times of application of the mixed liquid by each method is shown in Table 2. Further, the average thickness t of the obtained coating film was measured as follows. First, the coated metal plate was cut, and the cut test piece was embedded with a resin, and the cross section was produced by polishing. Further, a highly accurate observation cross section was produced by ion milling or the like, and any 10 points were observed by SEM. Then, the average value of the thicknesses measured at 10 places was taken as the average thickness t. In addition, the average surface roughness Ra _{(coating film)} of the obtained coating film was measured by the surface roughness measuring machine Surfcom 130A manufactured by Tokyo Seimitsu Co., Ltd. in accordance with JIS B0601:2001 (ISO 4287 ₎ . The measured values are shown in Table 2. In addition, it is evaluated whether the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} satisfy the following formula (1) or formula (2), respectively. In the evaluation of Table 2, the case where the formula (1) or the formula (2) is satisfied is denoted by 〇, and the case where it is not satisfied is denoted by ×. Ra _{(coating film)} ≧0.03/t+0.15 (1) Ra _{(coating film)} ≧0.08/t+0.12 (2)

[Evaluation] The presence or absence of interference fringes and the oil-based ink removal test (corrosion resistance) of the coated metal sheets obtained in each of the examples and the comparative examples were performed. The results are shown in Table 2.

(1) Confirmation of interference fringes The presence or absence of interference fringes is visually evaluated under a standard light source. The standard light source device is a trade name manufactured by X-Rite Co., Ltd.: Macbeth Judge II. In addition, the reference light is set to TL84. The interference fringes were evaluated on the basis of the following criteria. 〇: Not produced (effect on design: none) △: Slightly generated (impact on design: slight) ×: Apparently produced (effect on design: yes)

(2) Oil-based ink removal test (corrosion resistance) The coating obtained in the examples and the comparative examples was carried out using an oil-based marker (manufactured by Terashima Chemical Industry, trade name: Magic ink (registered trademark) No. 700 black). Draw on the metal plate. Then, one hour after the drawing and one hour later, the oily ink of the drawing portion was wiped with a cloth impregnated with water (manufactured by Asahi Kasei Corporation, trade name: Bemcot M3-II), and the oily ink after water wiping was evaluated. The extent of the traces. The traces of the oily ink were evaluated on the basis of the following criteria. ◎: no trace (removal rate is 100%) 〇: there is a slight trace (removal rate is 90% or more to less than 100%) △: traces (removal rate is 5% or more to less than 90%) ×: almost no Removal (removal rate less than 5%)

[Table 2] <TABLE border="1"borderColor="#000000"width="85%"><TBODY><tr><td> No. </td><td> Metal plate</td><td > Coating Film</td><td> Formula (1) </td><td> Equation (2) </td><td>Evaluation</td><td>Others</td><td></Td></tr><tr><td> metal plate</td><td> surface roughness Ra_{(metal plate)}</td><td>x^*1 (mol) </td><td> average thickness t (μm) </td><td> average surface roughness Ra_{(coating film)}</td><td> The number of coatings in the loading method () is </td><td> (0.03/t+0.15) </td><td> Evaluation </td><td> (0.08/t+0.12) </td><Td> evaluation </td><td> interference fringe</td><td> oily ink removal test</td></tr><tr><td> 1 minute later</td><td> 1 hour later </td></tr><tr><td> 1 </td><td> A </td><td> 0.21 </td><td> - </td><td> 0 </td ><td> - </td><td> - </td><td> - </td><td> - </td><td> - </td><td> - </td><Td> ○ </td><td> × </td><td> × </td><td></td><td> Comparative example</td></tr><tr><td> 2 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.19 </td><td> Roller coating 1 time) </td><td> 0.21 </td><td> × </td><td> 0.28 </td><td> × </td><td> × </td><td> ◎ </td><td> ◎ </td><td ></td><td> Comparative Example</td></tr><tr><td> 3 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.18 </td><td> Spray (1 time) </td><td> 0.21 </td><td> × </td><td> 0.28 </td><td> × </td><td> × </td><td> ◎ </td><td> ◎ </td><td></td><td> Comparative Example </td></tr><tr><td> 4 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.22 </td><td> atomized spray (4 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td> × </td><td> △ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr ><td> 5 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.25 </td><Td> Roller coating (1 time) + atomizing spray (6 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td> × </ Td><td> △ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><Td> 6 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.27 </td><td> Roll coating (1 time) + atomizing spray Fog (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td> × </td><td> △ </td><Td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 7 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.5 </td><td> 0.29 </td><td> Roller coating (1 time) + atomized spray ( 10 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 8 </td><td> B </ Td><td> 0.25 </td><td> 4.3 </td><td> 0.5 </td><td> 0.31 </td><td> Roller coating (1 time) + atomized spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 9 </td><td> C </td><td> 0.34 </td><td> 4.3 </td><td> 0.5 </td><td> 0.34 </td><td> Roller coating (1 time) + atomized spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td ><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 10 </td><td> D </td><td > 0.19 </td><td> 4.3 </td><td> 0.5 </td><td> 0.28 </td><td> Roller coating (1 time) + atomizing spray (8 times) </td><td > 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 11 </td><td> E </td><td> 0.22 </td ><td> 4.3 </td><td> 0.5 </td><td> 0.30 </td><td> Roller coating (1 time) + atomization spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </ Td><td></td><td> Example </td></tr><tr><td> 12 </td><td> F </td><td> 0.48 </td><Td> 4.3 </td><td> 0.5 </td><td> 0.36 </td><td> Roller coating (1 time) + atomized spray (2 times) </td><td> 0.21 </ Td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Reference example</td></tr><tr><td> 13 </td><td> F </td><td> 0.48 </td><td> 4.3 </td><td> 0.5 </td><td> 0.20 </td><td> Roller coating (1 time) </td><td> 0.21 </td><td> × </td><td> 0.28 </td><td> × </td><td> ○ </td><td> ◎ </td><td> ◎ </td><td> no interference fringe </td><td> Reference example</td></tr><tr><td> 14 </td><td> A </td><td> 0.21 </td><td> 3.7 </ Td><td> 0.5 </td><td> 0.29 </td><td> Roller coating (1 time) + atomizing spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></Td><td> Example </td></tr><tr><td> 15 </td><td> A </td><td> 0.21 </td><td> 6.6 </td><td> 0.5 </td><td> 0.29 </td><td> Roller coating (1 time) + atomized spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 16 </td><td> A </td><td> 0.21 </td><td> 3.2 </td><td > 0.5 </td><td> 0.29 </td><td> Roller coating (1 time) + atomizing spray (8 times) </td><td> 0.21 </td><td>〇</td><td> 0.28 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td> There is frost </td ><td> Comparative Example</td></tr><tr><td> 17 </td><td> A </td><td> 0.21 </td><td> 6.9 </td><Td> - </td><td> - </td><td> Roller (1 time) + atomized spray (8 times) </td><td> - </td><td> - </ Td><td> - </td><td> - </td><td> - </td><td> - </td><td> - </td><td> Unable to make film</ Td><td> Comparative Example</td></tr><tr><td> 18 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.2 </td><td> 0.28 </td><td> Roller coating (1 time) + atomizing spray (8 times) </td><td> 0.30 </td><td> × </td><td> 0.52 </td><td> × </td><td> × </td><td> ◎ </td><td> ◎ </td><td></td><td> Comparative Example</td></tr><tr><td> 19 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td > 0.2 </td><td> 0.30 </td><td> Roller coating (1 time) + atomizing spray (12 times) </td><td> 0.30 </td><td>〇</td><td> 0.52 </td><td> × </td><td> △ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 20 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 1.0 </td><td> 0.18 </td><td> atomized spray (4 times) </td><td> 0.18 </td><td>〇</td><td> 0.20 </td><td> × </td><td> △ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></ Tr><tr><td> 21 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 1.0 </td><td> 0.20 </td><td> atomization Spray (8 times) </td><td> 0.18 </td><td>〇</td><td> 0.20 </td><td>〇</td><td> ○ </td><Td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 22 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 1.5 </td><td> 0.18 </td><td> atomized spray (4 times) </td><td> 0.17 </td><td>〇</td><td> 0.17 </td><td>〇</td><td> ○ </td><td> ◎ </td><td > ◎ </td><td></td><td> Example </td></tr><tr><td> 23 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 2.8 </td><td> 0.18 </td><td> atomized spray (4 times) </td><td> 0.16 </td><Td>〇</td><td> 0.15 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td></td><td> Example </td></tr><tr><td> 24 </td><td> A </td><td> 0.21 </td><td> 4.3 </ Td><td> 2.8 </td><td> 0.14 </td><td> Spray (1 time) </td><td> 0.16 </td><td> × </td><td> 0.15 </td><td> × </td><td> × </td><td> ◎ </td><td> ◎ </td><td></td><td> Comparative Example </td>Td></tr><tr><td> 25 </td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 0.1 </td><Td> 0.19 </td><td> Spray (1 time) </td><td> 0.45 </td><td> × </td><td> 0.92 </td><td> × </td><td> × </td><td> ◎ </td><td> ◎ </td><td> Coating coverage × </td><td> Comparative example </td></tr><tr><td> 26 </ Td><td> A </td><td> 0.21 </td><td> 4.3 </td><td> 3.2 </td><td> 0.18 </td><td> atomized spray (4 Times) </td><td> 0.16 </td><td>〇</td><td> 0.15 </td><td>〇</td><td> ○ </td><td> ◎ </td><td> ◎ </td><td> Designability </td><td> Comparative Example</td></tr></TBODY></TABLE> ^*1 K ₂ O·xSiO The value of x in ₂

As shown in Table 2, when the average thickness t of the coating film and the average surface roughness Ra _{(coating film)} did not satisfy the case of the above formula (1) (in the case where the evaluation was ×), interference fringes were generated (No. 2, No. 3, No. 18, No. 24, and No. 25), when the equation (1) is satisfied (in the case where the evaluation is 〇), interference fringes are unlikely to occur (No. 4 to No. 12). No. 14 to No. 16, No. 19 to No. 23, and No. 26). It is presumed that by reflecting sufficient irregularities on the surface of the coating film, light reflected on the surface of the metal sheet and light reflected on the surface of the coating film are less likely to interfere. In addition, especially when the average thickness t of the coating film and the average surface roughness Ra _{(coating film)} satisfy the case of the above formula (2) (in the case where the evaluation is 〇), interference fringes are not generated (No. 7 to No. 12). No. 14 to No. 16, No. 21 to No. 23, and No. 26). However, if the average thickness t of the coating film exceeds 3.0 μm, the texture derived from the metal plate is lost (No. 26). In addition, when the surface roughness Ra _{(metal plate) of the metal plate} exceeds 4.0 μm, interference fringes (No. 13) are not generated even if the surface roughness after coating does not satisfy the above formula (1).

Further, in the case where the coating film was not formed, the oily ink mark (No. 1) could not be removed in the oily ink test. On the other hand, oil-based inks (No. 2 to No. 16 and No. 18 to No. 26) can be removed by forming a coating film. However, when the composition of the coating film is less than 3.5 in the composition formula K ₂ O·xSiO ₂ , frost is generated and the design property of the coated metal sheet is lowered (No. 16). On the other hand, when x is 6.8 or more, film formation (No. 17) cannot be obtained. Further, when the average thickness of the coating film is less than 0.2 μm, the coating film coverage is lowered to 92%, and the corrosion resistance is lowered (No. 25).

The present application claims priority based on Japanese Patent Application No. 2016-181359, filed on Sep. The contents described in the specification of the application are all incorporated in the specification of the present application. [Industrial availability]

The coated metal sheet of the present invention is excellent in stain resistance, does not cause interference fringes, and is excellent in design. Therefore, the painted metal sheet can be applied to a door material or an operation panel of an elevator, an outer panel of home electric appliances, furniture or daily necessities, various interior building materials, and the like.

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Claims (2)

A coated metal plate having: a metal plate having an average surface roughness Ra _{(metal plate)} of 0.40 μm or less; and a coating film formed on at least one surface of the metal plate, substantially comprising a composition formula K ₂ O· The composition represented by xSiO ₂ (3.5 ≦ x < 6.8) has an average thickness t of 0.2 μm or more and 3.0 μm or less; and an average thickness t of the coating film and an average surface roughness Ra _{of the coating film (coating film) )} satisfies the following formula (1), Ra _{(coating film)} ≧ 0.03/t + 0.15 (1). The coated metal sheet according to claim 1, wherein the average thickness t of the coating film and the average surface roughness Ra _{(coating film) of the coating film} further satisfy the following formula (2), Ra _{( Coating film)} ≧0.08/t+0.12 (2).