JPS5810152B2 - Method for manufacturing decorative metal plates with excellent corrosion resistance and durability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a decorative metal plate having excellent corrosion resistance and durability.

Conventional embossed metal plates are made by embossing a metal strip and stamping a concave-convex pattern on its surface, giving the surface a unique aesthetic appearance and improving mechanical structural cross-sectional performance, making it resistant to rough handling. Because it is difficult to yield and does not easily cause stickiness, it is suitable for interior and exterior panels, spindrels,
It is used in building materials such as door faceplates, partition walls, shutters and eaves, and in a wide range of other applications.

In particular, demand as building materials is rapidly increasing for colored steel plates that have been subjected to anti-rust treatments such as zinc plating, and then finished with paint or printing, as well as decorative metal plates that are further embossed on printed steel plates.

However, when embossing is performed after continuous painting or printing on the surface of a metal plate as described above, the corners of the convex portions of the surface of the metal plate that have been subjected to the uneven processing are elongated, so some of the corners are coated with a plating layer. Microscopic defects such as racks and pinholes may occur in parts of the paint, coating, and printed areas, resulting in a decline in corrosion resistance and durability.

In particular, when the depth of the embossing is increased in order to improve the effect of the embossing, the elongation of the corners of the textured portion becomes even greater, which exacerbates the above-mentioned defects.

Decorative metal plates obtained by embossing painted or printed metal plates have some advantages, but they still have problems with corrosion resistance and durability. It was considered unavoidable since the base material was a board.

This invention advantageously solves the above-mentioned problems, and has the characteristics of embossing, but also has excellent corrosion resistance, even after embossing after the usual finishing coating or printing in a painting or printing line. The purpose of this invention is to propose a method for continuously manufacturing decorative metal plates easily and inexpensively that can maintain durability.

The inventors conducted various experiments and studies to solve this problem, and found that the occurrence of cracks during embossing depends on the processing temperature. It has been found that the intended purpose can be advantageously achieved by heating and embossing in a region near the glass transition temperature of .

This invention is derived from the above knowledge.

In other words, the present invention provides a method for applying a textured pattern to a metal strip using an embossing roll forming machine after the usual finishing coating or printing in a painting or printing line, and immediately before the processing, the glass transition temperature of the coating resin is adjusted. This is a method for producing a decorative metal plate with excellent corrosion resistance and durability, in which heating is performed in the vicinity of the area.

This invention will be explained below with reference to two embodiments shown in FIGS. 1 and 2.

Figure 1 shows a case in which a metal strip such as a galvanized iron plate or an aluminum plate is subjected to continuous coating or printing in a conventional manner followed by embossing, and Figure 2 shows a metal coil that has been finished with continuous coating or printing in advance. This is the case when embossing is applied to

In FIG. 1, number 1 is a payoff reel, and number 2 is a metal strip rewound by the payoff reel 1.

3 is pinch roll, 4 is shear, 5 is stitcher-16
is an inlet accumulator, 7 is a base treatment tank, where the metal strip 2 is subjected to a base treatment, and is subsequently sent to a primer coater 8, a dryer 9, a finish coater 10. Printing machine 11.
While passing through the dryer 12, an undercoat and a finish coat or print are continuously applied.

Now, the metal strip 2 which has exited the dryer 12 and has been properly straightened by the tension leveler 13, and the previously continuously painted or printed metal strip 23 which has been rewound by the payoff reel 22 as shown in FIG. 2, is embossed. Immediately before applying this, the coating resin is heated to near the glass transition temperature region of the coating resin using a heating device 14.25, and then embossing is continuously performed using an embossing roll forming machine 15.26.

A temperature detector 16.27 is provided on the exit side of the embossing roll forming machine 15.26, which measures the temperature of the metal strips 2, 23 immediately after embossing, and sends this signal to the heating device 1.
4.25, the temperature of the heating devices 14 and 25 is controlled so that the metal strip 2 during embossing is always in the vicinity of the glass transition temperature region of the coating resin.

The heating device is equipped with a temperature control device, and electric or gas infrared heaters, hot air gas blowing and induction electric heating are advantageously suitable as heat sources.

Temperature detectors include contact type thermoelectric temperature detectors and non-contact type radiation temperature detectors, but when using a contact type temperature detector, there are issues such as the lifespan of the temperature detection element and the occurrence of contact scratches. From this point, the threading speed of the metal strip is 100m/
It is desirable to keep it within minutes.

Also, radiation temperature detectors are somewhat more expensive than contact types;
Although it takes time and effort to correct the vehicle and eliminate disturbances, it is advantageous for temperature control because it allows accurate temperature to be determined by using the metal strip appropriately without being affected by the speed at which the metal strip passes.

In Figure 1, 17 is an accumulator on the output side, 18 is an output shear, 19 is a winder, 20 is a running shear, 21 is a piler, 24 is a stitcher in Figure 2, and 128 is an output shear. be.

The metal strip used in this invention includes cold rolled steel plate,
Suitable galvanized iron plates, colored iron plates, stainless steel plates, tin-plated steel plates, aluminum plates, copper plates, aluminized steel plates, and printed steel plates.

In addition, for the coating film, it is usually preferable that the undercoat is an epoxy resin paint of about 4 to 6 μm in consideration of adhesion and corrosion resistance, and the top coat is an alkyd, acrylic, polyester, and silicone polyester resin paint of about 8 to 20 μm for corrosion resistance and aesthetics. The decorative metal plates obtained by heating the metal strips with these coatings to an appropriate temperature and then embossing them will not develop white rust even if they are exposed to harsh conditions for long periods of time as outdoor panel materials, for example. You can maintain an unaltered beauty.

In this invention, the appropriate heating temperature range for the painted or printed metal coil varies depending on the physical and chemical properties of each material substrate, but in any case, it is heated to near the glass transition temperature range of the coating resin. It was confirmed that a decorative metal plate without loss of corrosion resistance could be obtained by this method.

It goes without saying that various embossed patterns can be stamped depending on the purpose of use, such as plaster patterns, mesh patterns, geometric patterns, and wood grain patterns.

For reference, when embossing a galvanized iron plate that has only been subjected to a base plating treatment, immediately before embossing it, leave it at room temperature and at
The relationship between the heating temperature and the occurrence of cracks in the embossed convex portions when heated to various temperatures up to 0° C. was investigated, and the results of the investigation are shown in Table 1.

Material/Plate thickness x Plate width: 0.35 x 914 mm - Galvanizing thickness: 20 μm (one side) - Emboss shape: Irregular island-like patterns of 1.5 to 7 mm are arranged at irregular intervals of 1 to 2 mm. Something that stands out.

- Emboss depth: 1300 μm As is clear from Table 1, when embossing was performed at room temperature, cracks occurred on the entire convex part of the plating surface, but as the heating temperature of the metal strip immediately before embossing rose. The number of crank occurrences is reduced and the heating temperature is 6
It was confirmed that at temperatures above 0°C, almost no cracks were generated.

Next, according to the present invention, a galvanized iron plate was subjected to a base treatment, and then a color iron plate was baked with a coating film by two courses and two bakes, and then embossing was performed at room temperature and in a temperature range of up to 80°C. The corrosion resistance and durability of the decorative metal plate were investigated by conducting a salt spray test, a moisture resistance test, and a chemical resistance test, and the results are shown in Table 2.

Material/Plate thickness x Plate width: 0.27 x 914mm - Galvanized thickness 113μm (one side) - Type of base treatment: Zinc phosphate type - Base treatment layer thickness 10.3μm - Type of undercoat paint: Epoxy type / Undercoat Film thickness: 25 μm ・Type of finishing paint: Polyester light beige) ・Thickness of finishing paint film: 111 μm ・Embossed shape: Irregular island-like patterns of 1.5 to 7 mm are embossed and arranged at irregular intervals of 1 to 2 mm. What made me.

- Embossing depth: 23,008 m As is clear from the table, when embossing was performed at room temperature, the moisture resistance was fair, but the salt spray test and chemical resistance test results were both poor.

On the other hand, as the heating temperature immediately before embossing increases, corrosion resistance and hence durability improve, especially at heating temperature 5.
A decorative metal plate with excellent properties was obtained at temperatures above 0°C.

As described above, according to this invention, excellent corrosion resistance and durability are maintained even after embossing is applied to a painted or printed metal strip, significantly extending the lifespan of decorative metal plates compared to conventional methods. can.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are explanatory diagrams showing an embodiment of the present invention.

Claims (1)

[Claims] 1. When applying an uneven pattern to a metal strip using an embossing roll forming machine after the usual finishing coating or printing in the painting or printing line, immediately before the processing, the metal strip is coated in a region close to the glass transition temperature of the coating resin. A method for producing a decorative metal plate with excellent corrosion resistance and durability, which involves heating.