JP2001276728A - Painted metal plate with excellent design and abrasion resistance - Google Patents

Abstract

(57) [Abstract] [Problem] To improve the scratch resistance of a metal sheet having a beautiful appearance such as a stainless steel sheet or a 55% Al-Zn alloy hot-dip coated steel sheet, the transparency, the scratch resistance, and the workability are improved. All three properties provide a coated metal sheet with a good coating. SOLUTION: After a metal plate is subjected to chromate treatment, an epoxy, polyester or urethane-based undercoating film and a polyester or urethane-based overcoating film are formed. Resin particles or glass particles having a polar surface are contained so as to satisfy the formula. 0.7 <D / ht <2 0.7 <D / hp <4 D <lm <10D D: particle diameter, ht: top coat thickness, hp: undercoat thickness, lm: average distance between particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated metal sheet which is suitable for use in home appliances and indoor / outdoor building materials and which has excellent design properties, particularly excellent transparency and abrasion resistance.

The present invention is particularly applicable to the design of a clear-coated stainless steel sheet utilizing the metallic luster appearance of a stainless steel sheet and an Al-Zn hot-dip galvanized steel sheet containing 55% by mass of Al and sold under the trade name Galvalume. It can be applied to a clear coated steel plate that makes use of a certain appearance, or a coated aluminum plate that is continuously coated on an aluminum plate. Further, application to a coated steel plate used as a sliding member, such as a shutter slat material, is also conceivable.

[0003]

2. Description of the Related Art In assembling products using cold-rolled steel sheets and plated steel sheets, outer panels that are visible to humans are often used with some kind of coating for the purpose of improving corrosion resistance and design. It is.

Conventionally, such coating has been performed by an after-coating method in which coating is performed after assembly of a product.
Recently, the use of painted steel sheets (pre-coated steel sheets) that have been painted in advance has been increasing.

[0005] The increasing use of painted steel sheets
(1) Helps customers to omit processes, (2) Avoids the use of chemicals such as degreasing and painting, and (3)
In the case of a home appliance factory located near a city, it is difficult to upgrade a paint factory. In addition to these reasons, recently (4) special functions can be added,
(5) Positive reasons for improving the performance of painted steel plates, such as the possibility of imparting design properties, have come to be mentioned.

Among them, stainless steel sheets and plated steel sheets excellent in design (for example, Al-Zn alloy hot-dip coated steel sheets containing 55% Al) are conventionally not colored with paint in order to make use of the beauty of the material. In many cases, it was used as it is, but because of the demands of providing higher corrosion resistance and scratch resistance, and providing fingerprint resistance (making fingerprint adhesion less noticeable), transparent coatings that do not contain coloring pigments (Clear painting) is also increasing.

[0007] Japanese Patent Application Laid-Open No. 5-228433 discloses a coated steel sheet in which the coating film is less likely to be damaged or peeled off during the forming process. Discloses a coated steel sheet in which a powder aggregate having a thickness of not more than twice the thickness of the coating film is dispersed in the coating film. As the powder aggregate, silica powder, polytetrafluoroethylene powder, and mica powder are shown.

Although the addition of such an aggregate improves the scratch resistance of the coating film, the difference between the refractive index of the added aggregate and that of the binder resin of the coating film is too large.
A cloudiness remains in the coating film. Therefore, in the case where the appearance of the material is beautiful, even if an attempt is made to provide a highly transparent coating film in order to make use of the appearance, a beautifully sharp appearance is impaired by the coating film.

Japanese Patent Application Laid-Open No. 7-136585 discloses that an uppermost coating film mainly composed of an acrylic resin contains two or more kinds of mixed aggregates having different shapes of fibrous, granular, and powdery materials. A coated metal sheet excellent in scratch resistance and wear resistance is disclosed. However, in the case of such a paint mainly composed of an acrylic resin, the coating film is too hard to obtain sufficient workability, so that its use is significantly restricted.

JP-A-5-169584 and JP-A-5-106057 each disclose a coated stainless steel plate without coloring due to a coating base. These are either chromate treatment with addition of phosphate ions at a high reduction ratio (JP-A-5-106057) or colloidal silica treatment (JP-A-5-1695).
No. 84) as a base treatment and then coated with a transparent fluororesin.

Although excellent weather resistance can be exhibited by the fluororesin coating, fluororesins are expensive and thus are inferior in economical efficiency, and it is difficult to exhibit high workability (for example, 0T close contact bending). This is due to a decrease in workability due to the crystallization of the fluororesin, particularly, the vinylidene fluoride resin over time. Technical development has been carried out to suppress crystallization, but it is difficult at present to ensure 0T to 2T bending.

[0012]

The surfaces of electrical appliances and indoor / outdoor building materials made of painted metal plates are often cleaned with metal scourers or polished sand, but their abrasion resistance is insufficient. In such a case, the fold is damaged, and the transparency and gloss of the coating film are significantly impaired.

In particular, stainless steel plates, aluminum plates,
A clear coating is applied to a material with good metallic luster such as 55% Al-Zn alloy hot-dip coated steel sheet to improve the scratch resistance while maintaining the good appearance of the material. If it does, the transparency is impaired and the design is deteriorated.
However, the conventional coated metal plate with a clear coating film with excellent transparency has nothing to withstand scratches caused by washing with metal scourers or polished sand, and abrasion resistance that can withstand such washing There is a demand for a coated metal plate having (scratch resistance).

In addition to the wear resistance, the coated metal sheet is required to have high workability. This is because even if a clear coating film having good transparency and high design properties is provided, if the workability of the coated steel metal plate is inferior, the design and use as the outer panel of home electric appliances are limited.

[0015] It is an object of the present invention to provide a coated metal sheet provided with a coating film having all three properties of transparency, scratch resistance and workability.

[0016]

Means for Solving the Problems The present inventors have proposed that when at least one of the top coat and the undercoat of a clear-coated metal plate contains particles such as resin or glass beads, It has been noticed that the abrasion resistance (scratch resistance) can be significantly improved without impairing the transparency. Therefore, as a result of further studies, it has been found that when the particle diameter and the distribution density of the particles are within appropriate ranges, the improvement of the wear resistance can be surely obtained, and the present invention has been completed.

The present invention is a coated metal plate having two or more baking-type coating films on at least one surface of a metal plate subjected to a base treatment, wherein the lowermost coating film is selected from epoxy, polyester and urethane. One or more resins as a main component, the uppermost coating film mainly containing one or more resins selected from polyester and urethane, and (a) the uppermost coating film has a coating thickness ht Containing at least one kind of particles selected from resin particles and glass particles having a polar surface, having a particle diameter D satisfying the following formula (1),
The average inter-particle distance lm of the particles in the coating film satisfies the following formula (2), or (b) one or two or more lower coating films below the uppermost layer with respect to the coating film thickness hp. It contains at least one particle selected from resin particles and glass particles having a polar surface having a particle diameter D satisfying the following formula (1 ′), and the average inter-particle distance lm of the particles in the coating film is as follows: A painted metal plate excellent in design and abrasion resistance, characterized by satisfying the expression (2).

0.7 <D / ht <2 (1) 0.7 <D / hp <4 (1 ') D <lm <10D (2) D: particle diameter, ht: particle Containing uppermost layer coating thickness, hp: particle-containing lower layer coating thickness, lm: average interparticle distance.

Of course, the coated metal sheet of the present invention
(a) and (b) are satisfied, that is, the particles so that both the uppermost coating film and at least one lower coating film thereunder satisfy the above (a) and (b), respectively. It may be contained.

In the present invention, the average distance between particles is the average distance between particles, and a cross section in the thickness direction of a sample of a coated metal plate is observed over a length of 1000 μm using an electron microscope or an optical microscope. Then, the distance between all particles in the observation range was measured, and the average value was obtained.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The metal plate used as the material of the coated metal plate of the present invention is not particularly limited, but examples of suitable materials include stainless steel plates, aluminum plates and various types of plated steel plates. . The plated steel sheet may be manufactured by any of hot-dip plating, electroplating, and vapor phase plating, and typical types of plated metal include zinc, a zinc alloy, tin, and aluminum.

In the coated metal plate of the present invention, a clear coating film having excellent transparency can be used to make use of the beautiful appearance of the material, and abrasion resistance can be imparted without lowering workability. A material having a beautiful appearance that has been conventionally used without painting is preferable. Examples of such a material include a stainless steel sheet, an aluminum sheet, and a hot-dip galvanized steel sheet.

As stainless steel plates, SUS 430, SUS 4
30LX, SUS304, etc. are exemplified, and a glossy product having a surface finish of 2B or BA, or a stainless steel plate with improved design by polishing or the like is suitable. Preferred aluminum plates are 1100, 3004, 50
It is number 52. Examples of the hot-dip galvanized steel sheet include a hot-dip galvanized steel sheet and a hot-dip Al-Zn alloy-coated steel sheet having a beautiful spangle pattern, and particularly have a high Al content.
An Al-Zn alloy steel sheet of about 55% by mass has a beautiful spangle pattern, and is often used without painting.

If such a material is used as it is, the surface of the device is easily damaged by washing with a metal scrubber or polished sand, so that the design of appearance (beautifulness) deteriorates. In addition, dirt easily adheres to the damaged part, which further reduces the design.

When it is desired to make use of the design of the appearance of these materials, a suitable undercoating treatment is applied, and at least one of the top coat and the undercoat is subjected to a clear coating containing resin and / or glass particles. By forming at least two layers of the coating film according to the present invention, it becomes a coated metal plate having a clear coating film having good workability and abrasion resistance and excellent transparency, so that the design property and the scratch resistance are improved. Can be compatible. In the following, the case of forming a two-layer coating film of an undercoat and an overcoat will be mainly described. However, as described later, an intermediate coating film may be provided to form three or more coating films.

Chromate treatment is preferable as the base treatment for the metal plate, and coating type chromate treatment is advantageous from the viewpoint of workability. However, electrolytic or reactive chromate treatment is also applicable. . The amount of chromate attached in terms of chromium metal is preferably in the range of 10 to 200 mg / m ² . If the chromate adhesion amount is too small, sufficient adhesion of the coating film cannot be obtained,
If it is too large, the workability will be reduced. One example of a commercially available coating type chromate treatment liquid suitable for use in the present invention is NRC 300 manufactured by Nippon Paint. The coating type chromate treatment liquid is applied by a roll coater or the like according to a conventional method,
The base treatment may be performed by heating to 50 to 150 ° C. with hot air and drying.

If each of the undercoat and topcoat films is substantially transparent and it is desired to suppress the yellowness of the chromate film in order to utilize the appearance of the material, a chromate treatment having a high chromium reduction ratio may be applied. One example of such a commercially available chromating solution is NRC 500 manufactured by Nippon Paint.

If it is not desired to perform the chromate treatment using hexavalent chromium due to environmental problems, a chrome-free base treatment can be performed. A suitable chromium-free undercoating solution developed to date or to be developed in the future can be used, but one example of a suitable commercially available product at this time is:
It is a surf coat made by Nippon Paint which is a silica base treatment liquid.

The undercoating film (the lowermost coating film in the case of three or more layers) is formed from a baking type paint containing as a main component at least one resin selected from epoxy, polyester and urethane. These resins are particularly excellent in adhesion to an inorganic substrate such as a metal plate and can form a coating film having good workability. The paint used may be either a water-absorbing type or an organic solvent type.

Various epoxy paints are commercially available and may be used appropriately. For example, an epoxy paint containing melamine, amine, or isocyanate as a crosslinking agent may be used. As the epoxy resin type,
Bisphenol type epoxy resins are preferred.

The polyester paint is preferably a baking type obtained by mixing melamine or isocyanate as a crosslinking agent with a thermoplastic polyester resin. As the polyester, a so-called high molecular weight polyester resin having a molecular weight of about 5,000 to 20,000 is suitable from the viewpoint of processability. As the cross-linking agent, melamine modified with ethyl alcohol or butyl alcohol can be used. In some cases, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, or the like is appropriately used as a catalyst.

The urethane-based coating is a type of coating in which a polyester polyol is subjected to a crosslinking reaction with a yellowing type polyisocyanate or a non-yellowing type polyisocyanate to form a coating film. Examples of the crosslinking agent include isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HMDI). Again, dibutyltin dilaurate (D
A catalyst such as BTL) may be used as appropriate.

[0033] Any of these paints (optionally
Or a paint containing more than one kind of resin) may be applied on a metal plate on which a base treatment has been performed using an appropriate coating device such as a roll coater or a spray coater, and heated to bake the coating film. wear. The thickness of the coating film is preferably a relatively small thickness of about 3 to 15 μm as a dry film thickness. Baking is performed at about 30 to ensure that the maximum temperature of the steel sheet is about 150 to 250 ° C.
It can be carried out by baking for up to 60 seconds, and a conventional hot air blowing type oven, a heating method such as induction heating or infrared heating can be used.

The top coat (the top coat in the case of three or more layers) is formed from a baking type paint containing as a main component at least one resin selected from polyester and urethane. Epoxy resins are not suitable for use in topcoats because of their relatively poor weather resistance and processability. The polyester and urethane may be the same as those described above with respect to the undercoat film, but the urethane is preferably crosslinked using a non-yellowing isocyanate.

The top coat may also contain two or more resin types, if desired. Painting and baking of top coat
It can be carried out in the same manner as described for the undercoat paint. The thickness of the top coat is preferably in the range of 10 to 25 μm in dry film thickness. The top coat can be baked for about 30 to 70 seconds so that the maximum temperature of the steel sheet is 150 to 250 ° C.

According to the present invention, at least one of the undercoat film and the overcoat film contains resin particles and / or glass particles. That is, the particles are substantially uniformly dispersed in the paint to be used. Thereby, abrasion resistance can be imparted to the coating film, and a coated metal plate having excellent scratch resistance can be obtained.

In the present invention, the resin particles contained in the coating film include:
It may be made of any of a thermoplastic resin and a thermosetting resin, but has excellent adhesion with a binder resin in a coating film.
Resin particles having a polar surface are preferred. For example, resin particles having a non-polar surface, such as polytetrafluoroethylene (PTFE), have insufficient adhesion to the binder resin in the coating film and reduce the cohesive strength of the binder resin. Therefore, by adding PTFE particles, the friction coefficient of the coating film surface can be reduced, but not only the abrasion resistance cannot be sufficiently improved due to the decrease in the cohesive force of the binder resin, but also the workability and the like may be reduced. is there. Specific resin types of the resin particles include polyester, polyurethane, acrylic,
Melamine, polyamide and the like are exemplified.

Glass particles can be used instead of or in addition to the resin particles. Glass particles generally have a polar surface, and the adhesion between the coating film and the binder resin can be ensured. However, in order to improve the adhesion, the particles are treated with a coupling agent such as a silane coupling agent before use. You can also.

The shape of these resin or glass particles is
Preference is given to substantially spherical particles (beads), but oval,
It can also be an ellipsoid, a cylinder, a disk, and the like. The particle size of all particles may be substantially the same, and may be uniform, or may vary to some extent.

The size of the particles is related to the thickness of the coating film as follows:
When the particles are contained in the overcoat film, the following formula (1) is selected, and when the particles are contained in the undercoat film, the following formula (1 ') is selected: 0.7 <D / ht <2 ... (1) 0.7 <D / hp <4 (1 ') D: particle diameter, ht: thickness of top coat, hp: thickness of undercoat.

When there is a variation in the particle diameter of the particles, the average particle diameter is D. The average particle size takes a value of 50% of the volume cumulative particle size distribution curve. When the particle size of the particles exceeds twice the film thickness in the overcoat film and exceeds 4 times the film thickness in the undercoat film, the particles excessively protrude from the film, and the contact area ratio with the binder resin on the particle surface decreases. Therefore, particles easily fall off due to external force. As a result, for example, dropping of particles during passing through a normal coating line becomes noticeable, and the effect of improving abrasion resistance by the particles becomes insufficient. On the other hand, if the particles in the undercoating film have too large a protrusion, the work of overcoating becomes difficult. On the other hand, if the particles in the top coat, which is the uppermost layer, protrude too much, the particles easily fall off from the coating when subjected to an external force during processing or use, so that the effect of improving abrasion resistance is not maintained.

When the particle size is smaller than 0.7 times the film thickness, in both the undercoat film and the overcoat film, a considerable amount of the particles are buried in the coating film, and the desired abrasion resistance is reduced. The improvement effect does not appear sufficiently.

The particle diameter D preferably satisfies the following equation. Top coat: 1.0 <D / ht <1.2, Undercoat: 1.0 <D / hp <2.0.

The ratio of the particles present in the coating film is determined by the following formula, where the average distance lm between the particles in the coating film and the undercoating film is related to the particle diameter D of the particles.
In order to satisfy the expression (2): D <lm <10D (2) D: particle diameter, lm: average distance between particles.

When the average distance lm between the particles is
If the particle abundance ratio is smaller as it is larger than 10 times,
The effect of improving wear resistance due to the presence of particles cannot be substantially obtained. In the case of a top coat, if the particle size is large and the amount added is small, uneven distribution of the particles may be conspicuous, and the appearance of the particles may be poor. On the other hand, as the average particle distance Dm becomes smaller than the particle diameter D, the workability of the coated metal sheet is reduced when the proportion of the particles is large. The average inter-particle distance Im of the particles preferably satisfies the following equation.

3D <lm <8D In general, the standard of the blending amount of the particles satisfying the above formula (2) is, as volume% in the coating film, 20% or less in the case of the undercoating film and in the case of the overcoating film. Is 30% or less, and preferably 5% or more in any of the coating films.

In the coated metal sheet of the present invention, the effect of improving the abrasion resistance can be obtained only by containing the particles in one of the overcoat film and the undercoat film. Both may contain particles. In that case, a sufficient effect can be obtained even if the abundance ratio of the particles in each coating film is reduced within the range of the present invention. Even if the particles are contained only in the undercoat, the effect of improving the abrasion resistance is that at the place where the particles are present in the undercoat and project from the coating, the thickness of the subsequently applied topcoat becomes thinner This is considered to be due to the fact that it is difficult to deform and the hardness increases.

In the case of a normal coated metal plate, it is sufficient to form a two-layer coating film of an overcoat and an undercoat as described above. However, in order to further improve the appearance of the coating and the abrasion resistance, it is sufficient. Can be formed into three layers and an intermediate coat can be provided. The binder resin of the intermediate coating film may be the same as the top coating film. Particles can also be contained in the intermediate coating film, and in this case, the particle diameter D of the particles may be the same as in the case of the undercoat coating film. That is, when there are two or more coating films below the uppermost layer, the same particle diameter as described for the undercoating film is applied to these.

In the above, a preferred embodiment of the present invention has been described in which each coating film is a clear coating film containing no coloring pigment. Of course, it is also possible to use a metal plate. Further, the coating film according to the present invention may be formed only on one side serving as an outer plate of the material, but may be formed on both surfaces of the material as desired. When formed on only one surface, the unpainted surface may be bare or may be subjected to only a base treatment, or may be subjected to a coating different from that of the present invention. When forming on both surfaces, the composition of the undercoat and the overcoat does not need to be the same on both surfaces.

[0050]

[Example] Preparation method of test material SUS430 (plate thickness 0.5 mm, No.4 surface finish) stainless steel plate was used as the material, and NRC made by Nippon Paint was applied on one side of this material.
300 Chromate treatment liquid with 30 mg / m ²
Apply with a bar coater so that the maximum temperature is 100
C. for about 10 seconds to form a base chromate film.

The undercoat and the overcoat selected from the following are applied to the surface of the stainless steel sheet thus subjected to the base treatment, on which the chromate film has been formed, by using a bar coater so as to have a dry film thickness as shown in Table 1, respectively. Then, a coated stainless steel plate was produced by a two-coat two-bake method. Spherical particles (hereinafter, referred to as beads) shown below were added as fillers to one or both of the undercoat paint and the overcoat paint, and the particles were uniformly dispersed using a paint shaker before application. A hot air oven is used for baking. The maximum temperature of the steel sheet is 210 ° C for the undercoat and 230 ° C for the topcoat, and the baking time is 40 ° C for the undercoat.
Seconds, and 50 seconds for the top coat.

For comparison, a coated stainless steel plate containing neither beads nor a primer paint or containing silica as a filler instead of beads, and a resin type in the paint are outside the scope of the present invention. A coated stainless steel plate was similarly prepared.

<Undercoat clear paint> Epoxy paint (symbol PE) p670 (epoxy clear paint) manufactured by Nippon Paint Co., Ltd. Polyester-based paint (symbol PP) A resin liquid obtained by mixing Toyobo Byron 29CS (polyester) and Mitsui Cyanamid Cymel 303 (methyl alcohol-modified melamine) so that the solid content mass ratio becomes 8: 2. Then, PTSA (p-toluenesulfonic acid) as a catalyst was added in an amount of 0.3% by mass based on the solid content of the resin to prepare a clear paint. Urethane paint (symbol PU) Sumitomo Bayer Urethane alkynol 2013 (polyol) and isocyanate (TDI) manufactured by Sumitomo Bayer Urethane Co., Ltd. are mixed to give a solid content mass ratio of 6: 4.
(Dibutyltin dilaurate) relative to the resin solids
A clear paint was prepared by adding in an amount of% by mass.

<Overcoat clear paint> Preparation of polyester paint (symbol TP) Byron 63CS (polyester) manufactured by Toyobo and Cymel 303 (methyl alcohol-modified melamine) manufactured by Mitsui Cyanamid so that the solid content mass ratio becomes 85:15. Was added as a catalyst to the resin solution mixed in an amount of 0.3% by mass with respect to the resin solid content to prepare a clear paint. Preparation of urethane-based paint (symbol TU) Catalyst solution was added to a resin liquid in which alkynol 2013 (polyol) manufactured by Sumitomo Bayer Urethane and non-yellowing isocyanate (HMDI) manufactured by Sumitomo Bayer Urethane were mixed so that the solid content mass ratio was 6: 4. Was added in an amount of 0.1% by mass based on the solid content of the resin to prepare a clear paint. Acrylic paint (symbol TA: comparative material) Magiclon KX (acryl clear paint) manufactured by Kansai Paint was used.

[0055] Evaluation method For each coated stainless steel plate produced as described above,
Workability, scratch resistance and appearance were evaluated as follows. The test results are also shown in Table 1.

Workability (Bendability) One or more samples of a stainless steel plate having the same thickness are sandwiched between the samples with the painted surface on the outside, or the sample is 180 ° at 23 ° C. using a vise without being sandwiched. Bending was performed, and the processed portion was observed using a 30-fold loupe. Inspection was performed, and the maximum number of plate scissors that did not cause cracks in the coating film was evaluated. 0T means that no crack is seen in the coating film of the processed portion even by close bending (without sandwiching the plate). If it is from 0T to 2T, it was determined that the workability was good.

Scratch Resistance (Inspection of Dry Cotton Cloth) A dry cotton cloth was pressed against the painted surface of the sample with a load of 1 kg / cm ² and reciprocated 1000 times. Judgment was made and evaluated as follows: 傷: no scratches were seen with a 10-fold loop, Δ: scratches were seen with a 10-fold loupe, ×: scratches were seen with the naked eye.

Appearance (Film Integrity, Transparency) The painted surface of the sample was examined with the naked eye and palpation. When it was confirmed that there was no bumpy feeling, the film was judged to be sound. For transparency, color difference meter (45 ° -0 ° diffused light type)
As measured by, material after painting and L ₀ ^* value of (unpainted) L ^*
Delta L ^* of the difference between the value ^(* = L ^* -L ₀₎ is considered good that is 40 or less. When the transparency decreases and the coating film becomes whitish, L ^* increases and thus ΔL ^* also increases. The appearance was judged as ○ when both the above-mentioned film soundness and transparency were good, and as × when at least one of them was bad.

[0059]

[Table 1] In Table 1, Nos. 1-2 are Comparative Examples in which neither the undercoat film nor the overcoat film contains a filler, Nos. 3-16 are Examples in which fillers such as beads are contained in the undercoat film, and No. 17 ~
35 is an example in which a filler is contained in the overcoat film, No. 36 to
Numeral 40 is an example in which a filler is contained in both coating films.

[0060]

As can be seen from Table 1, the coated metal sheet according to the present invention has good workability and transparency, and excellent scratch resistance. Therefore, it is particularly useful to apply a clear coating to a material having a beautiful appearance to improve its scratch resistance.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B05D 7/24 303 B05D 7/24 303H B32B 15/08 B32B 15/08 G (72) Inventor Shusuke Kadochi Osaka-shi, Osaka 4-5-33 Kitahama, Chuo-ku Sumitomo Metal Industries Co., Ltd. (72) Inventor Yoichiro Shintani 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries Co., Ltd. F-term (reference) 4D075 AE03 CA02 CB06 DA06 DB01 DB04 DB05 DB07 DC01 EB33 EB35 EB38 EC03 EC53 4F100 AB01A AB04A AG00B AG00C AK41B AK41C AK51B AK51C AK53B BA03 BA07 BA10A BA10C CA23B CA23C CC00B CC00C DE01B DE01C EH46EJ48A EJ48 GB

Claims (3)

[Claims] 1. A coated metal plate having at least one side two or more layers of baked with type coating of metal plate surface treatment has been performed, the lowermost layer of the coating picked epoxy, polyester and urethane 1 The uppermost coating film is mainly composed of at least one resin selected from polyester and urethane, and the uppermost coating film has the following thickness with respect to its coating thickness ht: (1) It contains at least one kind of particles selected from resin particles and glass particles having a polar surface having a particle diameter D satisfying the formula, and the average inter-particle distance lm of the particles in the coating film is as follows: 2) A coated metal plate excellent in design and abrasion resistance, characterized by satisfying the formula. 0.7 <D / ht <2 (1) D <lm <10D (2) D: Particle diameter ht: Thickness of the uppermost coating film containing particles Im: Average interparticle distance 2. A coated metal plate having two or more baking-type coating films on at least one surface of a metal plate subjected to a base treatment, wherein the lowermost coating film is one selected from epoxy, polyester and urethane. The uppermost layer is mainly composed of one or more resins selected from polyester and urethane, and one or more lower layers below the uppermost layer are coated with the above-mentioned resin. It contains at least one kind of particles selected from resin particles having a polar surface and glass particles having a particle diameter D satisfying the following formula (1 ') with respect to the film thickness hp. The average distance between particles lm is
(2) A coated metal plate excellent in design and abrasion resistance, characterized by satisfying the expression (2). 0.7 <D / hp <4 (1 ') D <lm <10D (2) D: Particle diameter hp: Thickness of lower particle-containing coating film Im: Average distance between particles 3. The coated metal sheet according to claim 1, wherein each of the coating films is a clear coating film containing no coloring pigment.