JPH07205367A - Decorative metal plate material and manufacture thereof - Google Patents

Abstract

PURPOSE:To aftercoat only the metal surface of metal plate, which is developed at its cutting-off, by electrolytic deposition method so as to fit to mass- productivity in decorative metal plate material, on the front and rear sides of which plastic coating layer is laminatingly formed. CONSTITUTION:Plastic coating layer 1 is formed on the front and rear sides of metal plate 2. The metal plate 2 is cut into the predetermined shape. The cut decorative metal plate material 3 is electrolytically coated and electrolytically deposited film 5 is formed on the metal surface 2a developed at the cutting- off of the metal plate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention broadly covers metal plate materials widely used as, for example, components such as home electric appliances, building materials, indoor and outdoor equipment products, and in particular, a plastic coating layer is laminated on the front and back surfaces. A metal plate made from a metal plate that has been cut into a predetermined shape, such as die-cutting, punching or cutting and raising, is painted on the bare metal surface produced when the metal plate is cut for rust prevention and appearance measures. It has been processed.

[0002]

2. Description of the Related Art This kind of decorative metal plate material is generally pre-coated steel plate, that is, a metal plate having a decorative coating film formed on the front and back surfaces of the metal plate is obtained at the time of mass production. Cut into a predetermined shape such as dawn or cut and raised. Next, it is usually used by being bent into a desired shape according to the purpose. A decorative steel plate in which a plastic film is attached to the front and back surfaces of a metal plate may be used.

If such a plastic coating layer is formed on a strip steel sheet from a coil, the surface makeup (printed pattern of wood grain, metallic coating, embossed pattern, hammer tone coating, chilimen coating) and surface gloss adjustment. This is advantageous in that it can be freely performed, and since it can be efficiently produced, there is an advantage that the manufacturing cost can be reduced. Therefore, forming a plastic coating layer on a metal plate after die cutting, punching or cutting and raising processing does not allow the above surface makeup and gloss adjustment to be freely performed, and is inefficient in terms of mass productivity. There is no good idea.

[0004]

The problem is that when a metal plate such as a steel plate on which a plastic coating layer is previously formed is cut into a predetermined shape such as a die, a hole or a cut and raised part, the outer peripheral cut surface of the metal plate is cut. The inner surface of the hole and the cut and raised cut surface are bare metal surfaces, resulting in poor appearance and rust. If the metal plate is a plated steel plate and the plate thickness is large, the sacrificial anticorrosion effect of plating does not reach the entire cut surface,
It rusts quickly. Therefore, it is desired to post-coat this metal surface. However, in the conventionally known method such as spray coating, it is very difficult to select only the surface of the metal surface for post-coating, which is inefficient and expensive.

Therefore, the present inventor tried the above-mentioned post-coating by using the electrodeposition coating method, and found that the bare metal surface can be coated with a surprising efficiency without contaminating the plastic coating layers on the front and back surfaces. The present invention has been proposed. That is, the object of the present invention is to use a metal plate having a plastic coating layer formed on the front and back surfaces as a material, cut this into a predetermined shape, and then perform electrodeposition coating only on the metal surface of the metal plate by an electrodeposition coating method. The purpose is to obtain a decorative metal plate material that can coat the film efficiently and is excellent in mass productivity. Another object of the present invention is to obtain a decorative metal plate material which can surely finish the bare metal surface without staining the plastic coating layer.

[0006]

The present invention provides a decorative metal plate material 3 obtained by cutting a metal plate 2 having a plastic coating layer 1 laminated on the front and back surfaces thereof into a predetermined shape as shown in FIGS. 1 and 2. , Metal surface 2a produced when cutting the metal plate 2
In addition, the electrodeposition coating film 5 is formed by the electrodeposition coating method.

In the method of the present invention, the steps of forming the plastic coating layer 1 on the front and back surfaces of the metal plate 2, the step of cutting the metal plate 2 into a predetermined shape, and the cut decorative metal plate material 3 by electrodeposition coating. Then, the decorative metal plate material is manufactured through a step of forming the electrodeposition coating film 5 on the bare metal surface 2a generated when the metal plate 2 is cut.

[0008]

The metal plate 2 may have a plate thickness of 0.1 to 3.0 mm and has conductivity itself, and may be a steel plate, a stainless plate, an aluminum plate, a galvanized steel plate, an aluminized steel plate. A tin-plated steel sheet, zinc-aluminum-tin alloy-plated steel sheet, or the like can be used. When importance is attached to corrosion resistance and heat resistance, a zinc aluminum alloy plated steel sheet is preferably used. These metal plates 2 are coiled strips, and the plastic coating layer 1 is laminated on the front and back surfaces thereof. However, in the method of the present invention, it is also possible to previously cut the strip of the metal plate 2 into a predetermined length and then form the plastic coating layer 1 on the cut plate.

Surface coating step The plastic coating layer 1 is a coating layer coated with a plastic coating such as an epoxy resin or a polyester resin, or a laminated layer of a plastic film such as vinyl chloride, as long as it is a non-conductive decorative layer. Is a concept that includes. The plastic coating layer 1 is formed by laminating the metal plate 2 by pretreatment. Pretreatment is chemical conversion treatment with zinc phosphate or chromic acid,
A chemical conversion film is formed on the front and back surfaces of the metal plate.

When the plastic paint is applied to the metal plate 2, the coating is applied once and baked once, the primer and the surface coating are applied twice and the coating is baked twice, and the primer, the coating and the clear layer are applied three times. Any method such as coating and baking three times may be selected. In FIG. 1, the primer 1a is an epoxy type,
It can be formed with a plastic paint such as a fluorine-based, acrylic-based, or polyester-based paint. For the surface coating film 1b, a polyester-based, acrylic-based, or fluorine-based plastic paint can be used, and a free pattern such as metallic paint, hammer tone paint, or chilimen paint can be selected. The back surface coating of the metal plate 2 may be a single layer of polyester based coating film depending on the application. A print pattern or an embossed pattern can be provided on the surface coating film 1b as required. Then, if the metal plate 2 is continuously fed out from the coil and continuously coated on the metal plate 2 by roll coating or flow coating, the production efficiency is increased and it is desirable in terms of cost.

Cutting process The metal plate 2 on which the plastic coating layer 1 has been formed is shown in FIG.
As illustrated in (a) and (b), mold making A and punching B
A decorative metal plate material 3 is obtained by cutting into a predetermined shape such as a cut-and-raised C like a ventilation jar. After that, the decorative metal plate material 3 is bent into a desired shape as shown in FIG. This bending is preferably done after electrodeposition coating,
You may go before that. The decorative metal plate material 3 after electrodeposition may be in a flat plate shape without being bent later.

Electrodeposition coating process The cut decorative metal plate material (workpiece) is degreased and chemically converted by pretreatment of the metal surface 2a of the metal plate 2 (the inner and outer cut end surfaces of the hole 4). After that, it is immersed in the electrodeposition paint in the paint tank for electrodeposition coating. As a result, the electrodeposited coating film 5 is formed only on the metal surface 2a of the electrically conductive metal plate 2. Next, by pulling up the decorative metal plate 3 from the paint tank and washing it with water, the electro-deposition paint which is wet and does not adhere to the surface of the non-conductive plastic coating layer 1 is washed off, and the electro-deposition coating film is formed. 5. Dry and cure 5.

The electrodeposition coating may be either cation type electrodeposition coating or anion type electrodeposition coating, but cation type is preferable in consideration of corrosion resistance. As the cationic electrodeposition coating, a resin obtained by neutralizing a polyamine resin such as aminated epoxy with an organic acid such as formic acid or acetic acid to make it water soluble is used. As the anionic electrocoating material, a water-soluble alkyd resin, a water-soluble phenol resin, a water-soluble acrylic resin or the like is used. The thickness of the electrodeposition coating film 5 is set to 3 to 30 μm when corrosion resistance is required. That is, the minimum necessary corrosion resistance can be ensured at 3 μm or more, and 10 μm is sufficient in consideration of productivity, so it is usually set to 3 to 10 μm. However, particularly when corrosion resistance is strongly required, it is set to 10 to 30 μm. It should be noted that the one used indoors, which is not required to have corrosion resistance and only needs to hide the bare metal, has a film thickness of 1 μm.

[0014]

According to the present invention, unlike a mode in which a metal plate is cut and processed and then the entire cutting member is electrodeposited, a metal plate 2 having a plastic coating layer 1 formed on the front and back surfaces in advance is formed. This is a form in which die cutting, punching and cutting and raising are performed. Therefore, the metal plate material 3 obtained by the plastic coating layer 1 is not limited to one color of the electrodeposition coating, and the plastic coating layer 1 has various design characteristics. At the time of electrodeposition coating, the electrodeposition coating film 5 is not adhered and formed on the non-conductive plastic coating layer 1, and the electrodeposition coating wet on the plastic coating layer 1 can be easily washed off by subsequent washing with water. On the other hand, on the electrically conductive metal plate 2, the electrodeposited coating film 5 can be reliably and evenly applied to the outer peripheral cut end surface which becomes the base metal surface 2a, the inner peripheral surface of the hole 4 and the cut and raised cut end surface. Therefore,
The metal plate 2 does not have the bare metal surface 2a exposed, and is improved in design and is also excellent in rust prevention (corrosion resistance).

Since the electrodeposition coating method is used, a large amount of the metal surface 2a of the metal plate 2 can be continuously surface-treated even if the hole 4 has a small diameter, and the productivity is excellent. Since the plastic coating layer 1 can be continuously laminated on the front and back surfaces of the metal plate 2 in the state of strips from the coil, in this respect as well, it is suitable for mass production, and the decorative metal plate material can be provided at low cost. Moreover, since the electrodeposition coating is applied only to the metal surface 2a of the metal plate 2, the amount of electric power and the electrodeposition coating material are minimized, and the drying and curing time after electrodeposition is increased on the corresponding metal surface 2a. It has the advantage that it can be short because it requires only temperature.

[0016]

[Example] A 0.8 mm zinc-plated steel plate (metal plate) unrolled from a coil was chromated, and an epoxy resin paint was roll-coated on the surface and baked to give a dry thickness of 6 to 8
After forming a μm primer, roll coating with a high molecular polyester resin coating and baking to obtain a dry thickness of 2
A surface coating of 2 to 25 μm was formed by coating on the primer. High-polymer polyester resin paint on the back is 7μ dry
It was painted to be m. Next, the metal plate on which a plastic coating layer consisting of a primer and a surface coating film was formed was cut into a size of 10 cm × 20 cm, and as shown in FIG. I made several test pieces of plate material.

After degreasing and chemical conversion treatment of these test pieces, the test pieces were immersed in a tank containing an electrodeposition paint (Harwatop U-30 manufactured by Nippon Paint Co., Ltd.) in which an amino group was mixed with an epoxy resin, and the test pieces were placed. The electrode plate in the tank was used as an anode for the cathode, and coating was performed by direct electrodeposition between the electrodes. The energization condition at that time is 80 V to 1 in 30 seconds.
The voltage was raised to 50 V and this voltage was maintained for 60 seconds.
Then, the test piece was pulled up from the paint tank, washed with water, and dried at 200 ° C. for 1 minute to cure the electrodeposition coating film. Each test piece has a metal surface of the metal plate, that is, a cut end surface of the outer periphery and an inner peripheral surface of each hole, and the test piece 1 has 3 pieces.
μm, test piece 2 is 10 μm, test piece 3 is 2
A product coated with a 0 μm electrodeposition coating film was obtained. When it was washed with water in the washing step, the electrodeposition paint was easily washed off the surface of the plastic coating layer, and no damage was observed.

(Salt Spray Test) Previous Test Pieces 1 to 3
A salt spray test based on JIS-K-5400 was carried out on the above and those without the above electrodeposition coating (Comparative Example). Table 1 shows the test results. According to this, in the bare metal surface of the metal plate, that is, on the cut outer peripheral end surface portion and the inner peripheral surface portion of the punched hole, the bulging width of the surface coating film was 1 mm in 250 hours in the comparative example, and 1000 hours Then 1
It became 0 mm. On the other hand, in the examples of the present invention, the test piece 1 did not blister the coating film after 700 hours, and the test pieces 2.3 did not blister the coating film even after 1000 hours.

[0019]

[Table 1]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts after electrodeposition coating of a decorative metal plate material.

FIG. 2 is a perspective view illustrating a decorative metal plate material.

FIG. 3 is a perspective view showing a decorative metal plate material.

[Explanation of symbols] 1 plastic coating layer 2 metal plate 2a bare metal surface 3 decorative metal plate material 4 holes 5 electrodeposition coating film

Claims (2)

[Claims] 1. A decorative metal plate material obtained by cutting a metal plate having a plastic coating layer laminated on the front and back surfaces into a predetermined shape. The metal surface produced when the metal plate is cut is coated with an electrodeposition coating method. A decorative metal plate material having a coating film formed thereon. 2. A step of forming a plastic coating layer on the front and back surfaces of a metal plate, a step of cutting the metal plate into a predetermined shape, and an electrodeposition coating of the cut decorative metal plate material at the time of cutting the metal plate. A method of manufacturing a decorative metal plate material, which comprises a step of forming an electrodeposition coating film on the resulting bare metal surface.