JP6063088B1 - Painted metal plate - Google Patents

Abstract

An object of the present invention is to provide a coated metal plate having excellent stain resistance, no interference pattern, and excellent design. A coated metal plate is formed on a metal plate and at least one surface of the metal plate and is substantially represented by a composition formula K2O · xSiO2 (3.5 ≦ x <6.8). And a coating film made of a product. In the said coated metal plate, the average value of the coating-film coverage per mm <2> of the arbitrary 10 places which have the said coating film is 1 to 90%. [Selection] Figure 1

Description

  The present invention relates to a painted metal plate.

  For door materials such as elevators, operation panels, and the like, stainless steel plates having improved design properties by etching, coloring, surface treatment, and the like are used. These stainless steel plates are required to be resistant to fingerprints, high contamination resistance, high scratch resistance, and the like. Therefore, usually, a coating film made of resin, wax, oil or the like is formed on the surface of the stainless steel plate.

  However, when a coating film made of a resin is formed on the surface of a stainless steel plate, cracks and whitening occur in the coating film due to changes over time, and the design properties are likely to be impaired. Moreover, it is necessary to repaint wax and oil regularly.

  Then, forming the coating film which consists of inorganic materials on the surface of a stainless steel plate is examined (for example, patent document 1). A coating film made of an inorganic material is advantageous in that it hardly changes over time and has high hardness.

JP 2009-1685 A

  However, if the coating film made of an inorganic material is thin, the light reflected on the surface of the metal plate and the light reflected on the surface of the coating film are likely to interfere with each other, resulting in color unevenness or coloring (hereinafter also referred to as “interference pattern”). ) Is likely to occur. On the other hand, when the thickness of the coating film is increased, the texture (gloss or the like) derived from the metal plate is easily lost, and the design property is easily impaired. Moreover, in order to suppress an interference pattern, it is also considered that an aggregate is included in the coating film, but also in this case, the transparency of the coating film is likely to be lowered and the designability is easily impaired.

  In view of such a situation, the present invention has been made. That is, an object of the present invention is to provide a coated metal plate having excellent stain resistance, no interference pattern, and excellent design.

The present invention provides the following coated metal plates.
[1] A metal plate and a composition substantially formed by a composition formula K ₂ O · xSiO ₂ (3.5 ≦ x <6.8) formed on at least one surface of the metal plate. A coated metal plate having an average coating film coverage of 1 to 90% per 1 mm ^{2 at} any 10 locations having the coating film.

[2] The coated metal plate according to [1], wherein an average value of the coating film coverage is 3 to 80%.
[3] The coated metal plate according to [1] or [2], wherein the coating film includes a plurality of films formed in an island shape, and an average maximum width of the films is 500 μm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the coating metal plate which was excellent in stain resistance, an interference pattern does not arise, and was excellent in the designability is obtained.

1A is an SEM image of the coated metal plate produced in Example (No. 4), and FIG. 1B is an image obtained by measuring the Si distribution of the region with EDS and binarizing the image. 2A is an SEM image of the coated metal plate produced in Example (No. 5), and FIG. 2B is an image obtained by measuring the Si distribution of the region with EDS and binarizing the image. 3A is an SEM image of the coated metal plate produced in Example (No. 8), and FIG. 3B is an image obtained by measuring the Si distribution in the region with EDS and binarizing the image. 4A is an SEM image of the coated metal plate produced in Example (No. 9), and FIG. 4B is an image obtained by measuring the Si distribution in the region by EDS and binarizing the image.

  The present invention relates to a coated metal plate having a metal plate and a coating film formed discontinuously on the metal plate. The said metal coating plate is applicable to the door material of an elevator, an operation panel, the outer plate | plate of household appliances, furniture, furniture, a building material etc., for example.

  As described above, it has been studied to form a coating film made of an inorganic material on the surface of a metal plate for the purpose of improving the contamination resistance of the metal plate. However, when a relatively thin coating film was formed on the surface of the metal plate, an interference pattern was likely to occur. On the other hand, when the thickness of the coating film was increased, the design properties of the metal plate were liable to be impaired. In addition, in the conventional coated metal plate, the coating film was formed uniformly on the metal plate with a uniform thickness from the viewpoint of contamination resistance and the like.

On the other hand, the present inventors make it difficult for the interference pattern to be generated by forming the coating film discontinuously. Furthermore, the composition formula K ₂ O · xSiO ₂ (3.5 ≦ x <substantially). It was found that if the coating film is composed of the composition represented by 6.8), sufficient stain resistance can be obtained even if it is discontinuous.

  Even if the coating film covering the metal plate is discontinuous, the mechanism of developing stain resistance is considered as follows. In the coating film comprising the above composition, potassium is slightly eluted on the surface. And a potassium ion hydrates with the water | moisture content in air | atmosphere, and draws the water | moisture content in air | atmosphere. As a result, not only the coating film forming region but also the region between the coatings, that is, the region where the metal plate is exposed is covered with a thin water film. Therefore, even if oil stains such as sebum and oil-based ink adhere to the surface of the coated metal plate, the stains will float on the water film, and the stains can be easily removed by wiping or the like.

  In general, when time passes after the dirt adheres to the surface of the coated metal plate, some components of the dirt may impregnate the coating film or the metal plate, and it may be difficult to remove the dirt. On the other hand, in the coated metal plate according to the present invention, since a water film having a sufficient thickness is present on the surface of the coated metal plate, it is difficult for the dirt component to penetrate into the coated metal plate. Furthermore, since the coating film has high hydrophilicity, water easily penetrates between the surface of the coated metal plate and the dirt. Therefore, it becomes possible to remove the dirt adhering to the surface of the painted metal plate by wiping with water or the like.

  The coating film may be formed on only one surface of the metal plate, or may be formed on both surfaces. Moreover, the coating film may be formed only in the one part area | region of a metal plate, and may be formed in all the area | regions of one side or both surfaces of a metal plate.

Here, the average value of coating film coverage per 1 mm ² (hereinafter also referred to as “average coating film coating rate”) at any 10 locations having a coating film is 1 to 90%, preferably 3 to 80%. %, More preferably 10 to 80%, and still more preferably 15 to 80%. When the average coating film coverage is in the above range, an interference pattern is hardly generated and stain resistance is also easily exhibited. In addition, the shape of the area (1 mm ² ) for specifying the coating film coverage is not particularly limited, and may be any shape such as a rectangular shape such as a square or a rectangle, or a circular shape, but is usually a rectangular shape. . The average coating film coverage is specified by the following method.

Si element distribution is measured at any 10 locations (1 mm ² region) out of regions where a coating film is formed by SEM (scanning electron microscope) / EDS (energy dispersive X-ray spectroscopy). . Subsequently, the obtained Si distribution image is binarized by image processing software. In binarization, a region where Si is increased even a little is treated as a region where the coating film exists, based on the Si detection value of the coating film non-formed part (metal plate). Then, from the obtained binarized image, the number of pixels in the area where Si is increasing (area where the coating film exists) is divided by the total number of pixels to calculate the coating film coverage. And let the average value of these coating-film coverage be an average coating-film coverage.

  Here, the coating film is preferably composed of a plurality of films formed in an island shape. The film formed in an island shape is a film formed discontinuously and separated from other films. When the above-mentioned average coating film coverage is 50% or less, a film is easily formed in an island shape. In general, the outer peripheral length of each film is often 1600 μm or less. The shape of each film and the distance between the films are not particularly limited. The plurality of films may be formed in a uniform shape or may be formed in a non-uniform shape. Moreover, these may be formed at a uniform interval or may be formed at a non-uniform interval. However, the plurality of films are preferably formed on the metal plate with a substantially uniform density. If the formation density of the film is uneven, the above effects may not be obtained sufficiently. Further, if the area of each film is excessively large, the presence or absence of the film is easily visually recognized. Then, when a coating film consists of a some film | membrane formed in island shape, it is preferable that the average maximum width | variety of a film | membrane is 500 micrometers or less, and it is more preferable that it is 10-200 micrometers. The maximum width of each film is obtained from the above-described binarized image, and the average of the maximum widths of any ten films is the average maximum width.

  The average thickness of the coating film is preferably 0.05 to 3 μm, and more preferably 0.1 to 0.6 μm. When the average thickness of the coating film is 0.05 μm or more, the above-described effects are easily obtained. On the other hand, when the average thickness of the coating film is 3 μm or less, the visible light permeability of the coating film is sufficiently high, and it is difficult to impair the texture derived from the metal plate. The average thickness of the coating film is measured by arbitrarily cutting a coated metal plate and observing it from a cross section. Specifically, after embedding a test piece cut out from a coated metal plate with a resin, an appropriate cross section is prepared by polishing or the like, and a high-precision observation cross section is prepared by ion milling or the like. And about arbitrary 10 places in which a coating film exists, it observes by SEM and TEM, and let the average of 10 thickness be an average thickness.

  Here, the metal plate in the coated metal plate of the present invention is not particularly limited, and for example, austenitic stainless steel such as SUS304 or SUS316 or ferritic stainless steel such as SUS430 can be used. In applications where mechanical strength is required, materials obtained by cold hardening austenitic and ferritic stainless steel, martensitic stainless steel plates such as SUS410 and SUS420, and precipitation strengthened stainless steel plates such as SUS631 are used. It is preferable to use it. In addition to the stainless steel plate, copper, carbon steel, iron-nickel alloy, various plated steel plates, and aluminum plates may be used.

  These metal plates may be subjected to surface processing according to a conventional method. For example, the metal plate may have a smooth surface finish such as a BA finish or a mirror finish, and may have been subjected to a linear polishing process such as an HL finish for design and functionality. May be. Further, it may be subjected to curved polishing such as vibration polishing, or may be subjected to dot-like uneven processing. Further, it may be colored by various methods such as oxidation coloring or sputtering coloring.

On the other hand, the coating film is substantially composed of a composition represented by the composition formula K ₂ O · xSiO ₂ (3.5 ≦ x <6.8), and is composed of potassium silicate (K ₂ O · nSiO ₂ (2 ≦ n ≦ 4) and colloidal silica (SiO ₂ ) can be used to form a film obtained by coating and drying, where the compositional formula K ₂ O · xSiO ₂ is the state of the element in the coating film. In the coating film, SiO ₂ usually forms a siloxane bond, while potassium becomes a potassium ion, and a silicate ion that is not bonded to a siloxane bond. As described above, the coating film shows high hydrophilicity, but the hydrophilicity is high hydration property of potassium ions slightly eluting on the coating surface and the hydrophilicity of silanol groups. It seems to be expressed by sex That.

The ratio of silicon oxide (SiO ₂ ) to potassium oxide (K ₂ O) represented by x in the above composition formula may be 3.5 or more and less than 6.8, but 3.8 or more and 5.2. The following is more preferable. When the value represented by x is less than 3.5, potassium ions are excessively eluted on the surface of the coating film. In addition, the leached potassium ions are liable to occur as precipitated potassium ions react with carbon dioxide in the atmosphere to form carbonates. Moreover, when the value represented by x is less than 3.5, it is difficult to form a coating film sufficiently, and the average coating film coverage may not be in a desired range. On the other hand, when the value represented by x is 6.8 or more, it is necessary to mix a large amount of colloidal silica at the time of coating film formation. As a result, the film-forming property is lowered, the average coating film coverage may not be in a desired range, or the film may not have sufficient strength. In addition, the composition of the said coating film can be adjusted with the mixing ratio etc. of potassium silicate and colloidal silica. The composition of the coating film can be confirmed by EDS, XRF, EPMA, etc., and the chemical bonding state of Si can be confirmed by XPS, IR, or the like.

  The said coating film is obtained by apply | coating and drying the liquid mixture of potassium silicate and colloidal silica on a metal plate by the predetermined method so that it may become the above-mentioned average coating-film coverage. The potassium silicate and colloidal silica for forming the coating film may be general reagents or industrial chemicals. Examples of commercially available potassium silicate products include “A potassium silicate” and “2K potassium silicate” manufactured by Nippon Chemical Industry Co., Ltd., “No. 2 potassium silicate” manufactured by Fuji Chemical Co., Ltd., “ Snowtex K2 "etc. are included. On the other hand, examples of commercially available colloidal silica include “Adelite AT” manufactured by ADEKA, “Snowtex” manufactured by Nissan Chemical Industries, and “Silica Doll” manufactured by Nippon Chemical Industry.

  In addition, you may add a solvent, a leveling agent, an antifoamer, etc. to the liquid mixture for coating-film formation with potassium silicate and colloidal silica as needed. Further, the solid content concentration of the liquid mixture for forming the coating film is appropriately selected according to the method for forming the coating film. From the viewpoint of forming the film discontinuously and controlling the thin film thickness, The concentration is preferably in a relatively low range, and preferably 1 to 10% by mass.

  The method for applying the mixed liquid for forming a coating film is not particularly limited as long as the coating film can be formed so that the average coating film coverage is in the above-described range. For example, it is possible to use a method of applying the mixed solution by a spray gun, an electrostatic atomizer, an ink jet device, a gravure roll transfer device or the like. When forming a coating film with a spray gun or electrostatic atomizer, the spray nozzle diameter of the spray gun or electrostatic atomizer is reduced or the atomization pressure is adjusted to adjust the average coating film coverage. It is preferable to devise such as.

  The method for drying the mixed solution is not particularly limited as long as the solvent can be sufficiently volatilized. For example, you may dry at normal temperature, but you may heat at 80-300 degreeC. By heating, drying of the solvent water is promoted, and film formation is promoted. Furthermore, by heating to 200 ° C. or higher, formation of siloxane bonds is promoted, and a strong coating film can be obtained in a short time. However, pay attention to discoloration (temper color) due to oxidation of the original plate when heating. The drying time is usually about 10 to 30 minutes when heated, and 24 hours is sufficient even when drying at room temperature.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited by these Examples.

  A coated metal plate was prepared by the following method, and for each, the contamination resistance of the surface and the presence or absence of interference patterns were confirmed. In addition, the metal plates A to E shown in Table 1 below were used as the metal plates.

[Preparation of painted metal plate]
Potassium silicate (made by Fuji Chemical Co., Ltd., trade name: No. ₂ potassium silicate, K ₂ O.nSiO ₂ (n = 3.61), or Fuji Chemical Co., Ltd., trade name: No. 1 potassium silicate, K ₂ O · nSiO ₂ (n = 2.04)) and colloidal silica (manufactured by Nippon Chemical Industry Co., Ltd., trade name Silica Doll) were mixed at a mass ratio shown in Table 2 in terms of solid content to obtain a mixed solution. The mixed solution was applied to the metal plates A to E by an atomizing spray so that the average coating film coverage shown in Table 2 was obtained. Then, it was made to dry at 250 degreeC for 20 minutes, and the coating film was obtained. In addition, all the average thickness of the obtained coating film was 0.6 micrometer or less. The average thickness was measured as follows. First, a coated metal plate was cut out, and the cut test piece was embedded in resin and then polished to produce a cross section. Further, a highly accurate observation cross section was prepared by ion milling or the like, and observed with an SEM. Thickness was measured about arbitrary 10 places where a coating film exists, and these average was made into average thickness.

Moreover, the average coating-film coverage per mm < ² > was measured as follows.
First, using SEM (manufactured by Hitachi High-Technologies Corporation, product name: S-3700N) / EDS (manufactured by Oxford Instruments Co., Ltd., product name: x-act), the element distribution of Si as the main component of the coating film was measured. did. The measurement was performed on arbitrary 10 locations (1 mm ² ) in the region where the coating film was formed. Next, the obtained Si distribution image was binarized with image processing software (manufactured by Adobe, photoshop). At the time of binarization, a region where Si was slightly increased was treated as a region where the coating film was present, based on the Si detection value of the coating film non-formed part (metal plate). From the obtained binarized image, the number of pixels in the region where Si increases (region where the coating film exists) is divided by all the pixels in the region to calculate the coating film coverage. And the average value of the coating-film coverage was computed, and this was made into the average coating-film coverage. No. FIGS. 1 to 4 show SEM images and binarized images of 4, 5, 8, and 9 by measuring the Si distribution in the region with EDS.

[Evaluation]
About the coated metal plate obtained in each Example and the comparative example, the oil-based ink removal test (contamination resistance) and the presence or absence of an interference pattern were confirmed. The results are shown in Table 2.

(1) Oil-based ink removal test (contamination resistance)
It drew with the oil-based marker (The product made from Teranishi Chemical Industry, brand name: Magic ink (trademark) No. 700 black) on the coating metal plate obtained by the Example and the comparative example. Then, after 1 minute and 1 hour from the drawing, the oil-based ink in the drawing part was wiped off with a cloth impregnated with water (product name: Bencott M3-II), and traces of the oil-based ink after wiping with water were removed. The degree was evaluated. The trace of oil-based ink was evaluated according to the following criteria.
A: No trace (removal rate 100%)
A: There is very little trace (removal rate 90% or more to less than 100%)
Δ: Traces (removal rate 5% to less than 90%)
X: Almost no removal (removal rate less than 5%)

(2) Confirmation of interference pattern The presence or absence of the interference pattern was visually evaluated under a standard light source. As the standard light source device, trade name: Macbeth Judge II manufactured by X-Rite was used. The reference light was TL84. The interference pattern was evaluated according to the following criteria.
○: No occurrence (effect on design: none)
△: Slightly generated (effect on design: minor)
×: Significant occurrence (influence on design: yes)

  As shown in Table 2, when no coating film was formed (average coating film coverage: 0%), oil-based ink marks could not be removed in the oil-based ink test (No. 1). On the other hand, if the average coating film coverage was 1% or more, the oil-based ink could be removed in any case (Nos. 2 to 16 and 18 to 21). However, when the average coating film coverage was 95% or more, an interference pattern occurred (Nos. 12 and 13).

Further, the composition constituting the coating, the composition formula _{K 2} O · xSiO 2 of x is less than 3.5, efflorescence occurs, the design of the coated metal plate is lowered (No.16). On the other hand, when x was 6.8 or more, film formation was not possible (No. 17).

  The coated metal plate of the present invention is excellent in stain resistance, has no interference pattern, and is excellent in design. Therefore, the coated metal plate can be applied to door materials and operation panels for elevators, outer plates for home appliances, furniture, furniture, various interior building materials, and the like.

Claims (2)

A metal plate,
A coating film formed of at least one surface of the metal plate and made of a composition substantially represented by the composition formula K ₂ O · xSiO ₂ (3.5 ≦ x <6.8);
Have
Wherein any 10 points with a coating film, the average value of the coating film coverage per 1 mm ² is Ri 26-90% der,
The average thickness of the coating film is 0.1 to 0.6 μm ,
Painted metal plate. The coating film comprises a plurality of films formed in an island shape,
The average maximum width of the film is 500 μm or less,
The coated metal plate according to claim 1 .