KR102130531B1 - Method for manufacturing colored Zn-Mg-Al coated steel sheet using CGL - Google Patents

Abstract

A method of manufacturing a colored plated steel sheet using a CGL process is provided.
The colored plated steel sheet manufacturing method of the present invention, in the CGL (Continuous Galvanized Line) process, the holding steel sheet, the bath temperature is 440 ~ 465 ℃, Al: 1.1 ~ 1.7% by weight, Mg: 1.1 ~ 1.7%, Zn : Process for manufacturing a hot-dip galvanized steel sheet by continuously immersing in a hot dip galvanizing bath containing magnesium containing 96.6 to 97.8% and impurities, followed by drying; In addition, a colored coating device, which is a post-treatment device, was installed at the rear end of the CGL process, and, on the surface of the prepared hot-dip zinc alloy plated steel sheet, by weight, 0.5 to 5% of Si compound, 48 to soluble anionic urethane-acrylic copolymer resin 58%, chromium reducing agent 0.3~5%, Chromium trioxide 0.2~5%, fluorine-modified PE-based wax 1~5%, pigment 1~10%, and the color coating solution containing the remaining water and then dried to coat the color coating layer It includes; the process of forming a.

Description

Method for manufacturing colored Zn-Mg-Al coated steel sheet using CGL process

The present invention relates to a method for manufacturing a colored hot-dip zinc (Zn-Mg-Al) plated steel sheet to which color is applied, and more specifically, a low-cost type by imparting high corrosion resistance while simultaneously applying color to the top of a high-corrosion hot-dip galvanized steel sheet. It relates to a method for manufacturing a colored plated steel sheet using a CGL process that can give the same effect as a single color PCM (Pre Coated Metal) steel sheet.

In general, the plated steel sheet has a silver-white metallic feel. However, it has been used for various building materials such as sandwich panels by applying color coating to enhance the corrosion resistance and give the design a beautiful appearance. However, in the case of the color PCM steel sheet, there is a problem in that the process cost is increased because it is manufactured through CCL (Color Coated Line) process after production of hot-dip galvanized steel sheet.

On the other hand, after the CGL (Continous Galvanized Line), post-processing coating equipment that gives zinc rust, lubricity, etc. through post-treatment coating after plating the molten metal such as Zn, Al on the iron in the base. Is putting. However, the post-processing of CGL is transparent, so the metal feeling of the plated steel sheet is revealed.

In addition, in the case of CCL, in order to realize color and physical properties, the film thickness is thick, the drying temperature is high, and the line speed is slower than that of CGL. Moreover, the PCM steel sheet is composed of several structures such as top, middle, and bottom, so it has a big difference from the CGL facility in that it repeats coating and drying 2~4 times. It is very difficult to implement.

Therefore, the present invention, unlike the prior art of producing a colored coated steel sheet using a CCL process after the manufacture of Zn-Mg-Al ternary high corrosion-resistant plated steel sheet, imparts color using CGL's post-treatment equipment and post-treatment solution. It is an object of the present invention to provide a method for manufacturing a colored plated steel sheet using a CGL process.

In addition, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly understood by a person having ordinary knowledge in the technical field to which the present invention belongs from the following description. It could be.

The present invention for achieving the above object,

In the CGL (Continuous Galvanized Line) process, the steel sheet, the bath temperature is 440 ~ 465 ℃, by weight Al: 1.1 ~ 1.7%, Mg: 1.1 ~ 1.7%, Zn: 96.6 ~ 97.8% and containing impurities A process of manufacturing a hot-dip galvanized steel sheet by continuously immersing in a hot-dip galvanizing bath containing magnesium and then drying; And

A colored coating device, which is a post-treatment device, is installed at the rear end of the CGL process, and on the surface of the prepared hot-dip galvanized steel sheet, by weight, 0.5 to 5% of Si compound, 48 to 58 of water-soluble anionic urethane-acrylic copolymer resin %, Chromium reducing agent 0.3~5%, Chromium trioxide 0.2~5%, Fluorine-modified PE-based wax 1~5%, Pigment 1~10%, and the remaining coating water Forming process; relates to a method for manufacturing a high corrosion-resistant colored steel sheet using a CGL process comprising.

In the step of forming the colored coating layer, it is preferable to coat the colored coating solution with 1100 to 4000 mg/m 2 and then dry.

It is preferable that the thickness of the colored coating layer is 1 to 4 μm.

According to this aspect of the present invention, by not going through the conventional CCL process to impart color, it is possible to solve the high manufacturing cost problem.

1 is a schematic cross-sectional view showing a highly corrosion-resistant colored plated steel sheet coated with a coloring solution according to an embodiment of the present invention.

Hereinafter, the present invention will be described.

The high corrosion-resistant colored plated steel sheet of the present invention includes a high corrosion-resistant zinc alloy plating layer plated on the surface of the base steel plate, and a coloring coating layer coated on the surface and/or the back surface of the high corrosion-resistant magnesium zinc alloy plating layer.

The highly corrosion-resistant colored plated steel sheet, in the CGL (Continuous Galvanized Line) process, the holding steel sheet, the bath temperature is 440 ~ 465 ℃, Al: 1.1 ~ 1.7% by weight, Mg: 1.1 ~ 1.7%, Zn: 96.6 Process for manufacturing a hot-dip galvanized steel sheet by continuously immersing in a hot dip galvanizing bath containing magnesium containing ˜97.8% and impurities, followed by drying; In addition, a colored coating device, which is a post-treatment device, was installed at the rear end of the CGL process, and, on the surface of the prepared hot-dip zinc alloy plated steel sheet, by weight, 0.5 to 5% of Si compound, water-soluble anionic urethane-acrylic copolymer resin 48~ 58%, chromium reducing agent 0.3~5%, Chromium trioxide 0.2~5%, fluorine-modified PE-based wax 1~5%, pigment 1~10%, and the color coating solution containing the remaining water and then dried to coat the color coating layer It may be manufactured by a manufacturing method comprising a; forming process.

In the present invention, in order to manufacture a highly corrosion-resistant colored coated steel sheet, a hot-dip galvanized steel sheet is manufactured using a CGL (Continuous Galvanized Line) process. Then, a colored coating device is installed at the rear end of the CGL process to form a colored coating layer on the surface of the hot-dip galvanized steel sheet discharged continuously from the CGL process.

That is, first, in the present invention, a steel sheet is prepared. It is preferable that such a steel sheet has been subjected to a pre-treatment process for surface cleaning such as removal of scale of the material, and an annealing process for enhancing plating adhesion. In addition, the present invention is not limited to the components and types of the steel sheet.

In the present invention, in the CGL process, the steel sheet, the bath temperature is 440 ~ 465 ℃, Al: 1.1 ~ 1.7% by weight, Mg: 1.1 ~ 1.7%, Zn: 96.6 ~ 97.8% and magnesium containing impurities A hot dip galvanized steel sheet is prepared by continuously immersing in a hot dip galvanizing bath and drying.

The high corrosion-resistant magnesium zinc alloy plating layer, by weight, Al: 1.1 to 1.7%, Mg: 1.1 to 1.7%, it is preferable to include Zn: 96.6 to 97.8%.

And the adhesion amount of the molten magnesium zinc alloy plating layer adhered to the steel sheet is also not limited, but is preferably limited to 90 g/m 2 (based on both sides, 45 g/m 2 on one side) or more. This is because when the plating amount of the plating layer is less than 90 g/m 2, it is difficult to satisfy excellent corrosion resistance properties.

Subsequently, in the present invention, in the post-treatment process of CGL, Si or 0.5 to 5% by weight of Si compound, 48 to 58% of water-soluble anionic urethane-acrylic copolymer resin on one or both sides of the steel sheet having the high corrosion-resistant magnesium zinc alloy plating layer formed thereon , Chromium reducing agent 0.3 ~ 5%, Chromium trioxide 0.2 ~ 5%, fluorine-modified PE-based wax 1 ~ 5%, pigment 1 ~ 10%, coating the coloring solution consisting of residual water.

In the present invention, the Si compound promotes adhesion between the material and the solution, and serves to increase scratch resistance. If the Si compound is less than 0.5%, the adhesion with the material is poor and the post-treatment peels off during processing. If it exceeds 5%, there may be a problem in solution storage stability.

The water-soluble anionic urethane-acrylic copolymer resin serves as a binding and cohesive agent for the solution and affects corrosion resistance.

The Chromium trioxide is added for the purpose of improving corrosion resistance, and when the content is less than 0.2% by weight, the corrosion resistance is deteriorated, which makes it difficult to satisfy physical properties. If it exceeds 5%, a shock phenomenon may occur.

The chromium reducing agent neutralizes Chromium trioxide.

The fluorine-modified PE-based wax serves to help prevent scratching by minimizing friction during processing through the provision of lubricity. When the wax component is less than 1% by weight, there is a risk of scratching due to a large frictional force, which causes the solution coating layer to peel off. In addition, when the excess amount is added in excess of 5% by weight, the lubricity is excessively increased. Therefore, it is preferable that the wax component contains 1 to 5% by weight.

The pigment may be a water-soluble pigment. To adjust the color transparency, the content is adjusted, and if it is less than 1%, the color is not displayed, and if it exceeds 10%, it is uneconomical because it is unnecessaryly added excessively.

At this time, when coating the coloring solution, it is preferable to manage the coating adhesion amount in the range of 1100 ~ 4000mg / ㎡. When the solution adhesion amount is less than 1100 mg/m 2, corrosion resistance is deteriorated.

Subsequently, in the present invention, the zinc alloy plated steel sheet coated with the coloring solution is dried at a temperature of 100° C. for 15 seconds or more to form a final coating layer.

Hereinafter, the present invention will be described through examples.

(Example 1)

By applying CG process to the surface of the cold rolled steel sheet of 0.45T, plating adhesion amount 120g/㎡ (one side 60g/㎡) is applied in weight%, including Al: 1.1~1.7%, Mg: 1.1~1.7%, Zn: 96.6~97.8% The hot-dip zinc alloy plated steel sheet was manufactured. Subsequently, in a continuous CGL post-treatment process, 2% by weight of Si compound on the surface of the hot-dip zinc alloy plated steel sheet, 52% of water-soluble anionic urethane-acrylic copolymer resin, 2.5% of Chromium trioxide, 5% of chromium reducing agent, 2% of wax, A coloring solution composed of pigment 2% and residual water was coated with different coating amounts as shown in Table 1 below to prepare a hot-dip galvanized steel sheet containing high corrosion-resistant magnesium with a colored coating layer formed on its surface.

Thus, the characteristics were evaluated by the following evaluation criteria prepared, and the results are also shown in Table 1 below.

<Adhesive amount>

The adhesion amount was evaluated using an XRF instrument.

<appearance>

The appearance was evaluated by the presence or absence of roll marks caused by the rolls of the post-treatment equipment used when painting the coloring solution. The roll marks occur in a vertical line. When the roll marks occurred clearly, they were evaluated as 0 points and 5 points when applied uniformly without the roll marks.

<Corrosion resistance>

The corrosion-resistant plate was evaluated as 5 points within 5%, 4 points within 10%, 3 points within 20%, 2 points within 30%, 40% or more and 1 point after satisfactory within 5% of white rust after 500 hours at 5% NaCl, 35℃.

In the case of the processing part, 6 mm processing by Ericsson test method, 5% NaCl, after 120 hours at 35°C When white rust occurs within 5%, 5 points within 10%, 4 points within 10%, 3 points within 20%, 2 points within 30% 40 % Or more.

<Moisture resistance>

Moisture-resistant flat plate with color difference meter after 50 hours at 50℃, 90% environment, 5 points, ΔE is 4 or less 4 points, ΔE is 5 or less 3 points, ΔE is 6 or less 2 A point and (DELTA)E were rated as 7 or more and 1 point.

Lamination is 50K, 20Kg _f .cm ² at 90% environment, and after 120 hours under load, 5 points if the measured value satisfies ΔE≤3 before and after the experiment with a color difference meter, ΔE is 4 or less, 4 points, ΔE is 5 The following three points were evaluated, ΔE was 6 or less, 2 points, and ΔE was 7 or more and 1 point.

<Chemical resistance>

The chemical resistance is 5% alkali, 5% acid, respectively. Drops on the surface of colored paint. After curing for 5 minutes, the color difference meter gives 5 points when the measured value satisfies ΔE ≤ 3, ΔE is 4 or less, 4 points, ΔE is 5 or less, 3 points. , ΔE was 6 or less and 2 points, ΔE was 7 or more and 1 point.

<Friction coefficient>

The friction coefficient was measured using Alteck Mobility Tester.

<Film adhesion>

The flat plate adhesiveness (Cross Cut Test) was evaluated by crossing the surface of the dried colored paint with a cutter knife at intervals of 1 mm to make 100 divisions, and then squeezing and peeling the 3M transparent tape. The number of cells attached without being separated by the transparent tape among the 100 divisions was indicated.

The adhesion of the processed part (Cross Cut Erichsen Test) was evaluated by making 100 graduations on the surface of the colored coating surface in the same manner as the above method, and then conducting a 6mm Erichsen Test, squeezing and removing 3M transparent tape. The number of cells attached without being removed by the transparent tape among the 100 divisions was indicated.

<Fingerprint resistance>

The anti-fingerprint property was evaluated by measuring the color difference with a colorimeter one hour before and after applying vaseline on the surface of the colored paint. When ΔE≤2 was satisfied, 5 points, ΔE was 3 or less, 4 points, ΔE was 4 or less, 3 points, ΔE was 5 or less, 2 points, ΔE was 6 or 1 point.

<Boiling water resistance>

The boiling water resistance was evaluated after the deposition of pure 100 ± 3℃, 5min, and then taken out, 0T 180° bending, and then attaching and detaching 3M transparent tape to the banding part, peeling and cracking of the processed surface. If it did not adhere to the transparent tape, it was evaluated as 5 points, and when peeling and cracking occurred, it was evaluated as 1 point.

Item Comparative Example 1 Inventive Example 1 Inventive Example 2 Comparative Example 2 Adhesion amount (mg/㎡) 1000 1500 4000 4500 Exterior 2 points 4 points 5 points 5 points Corrosion resistance reputation 2 points 5 points 5 points 5 points Processing 2 points 5 points 5 points 5 points Moisture resistance Type 2 points 5 points 5 points 5 points Lamination 2 points 5 points 5 points 5 points Chemical resistance alkali 2 points 5 points 5 points 3 points mountain 2 points 5 points 5 points 3 points Coefficient of friction 0.03 0.01 0.01 0.02 Film adhesion reputation 100/100 100/100 100/100 100/100 Processing 100/100 100/100 100/100 50/100 Anti-fingerprint 3 points 5 points 5 points 4 points Boiling water resistance 1 point 5 points 5 points 1 point

As can be seen from the experimental results in Table 1, it can be seen that the amount of the colored solution adheres to the physical properties, and the optimum adhesion amount is less than 1000 mg/m2 and less than the maximum of 4500 mg/m2.

(Example 2)

The same evaluation as in Example 1 was performed to compare the colored high corrosion-resistant plated steel sheet of Inventive Example 2 of Example 1 in which the color was directly applied in the CGL process on the high corrosion-resistant magnesium galvanized steel sheet layer to the low-cost PCM steel sheet produced in the conventional CCL process. The results are shown in Table 2 below.

The plated steel sheet used in the conventional CCL process is a hot-dip galvanized steel sheet containing 98% Zn and 0.2% Al by weight, and on the surface of the hot-dip galvanized steel sheet in the CCL process, by weight%, 50% ceramic resin, poly Ester resin 10%, melamine resin 5%, isocyanate resin 5%, antifoaming agent 0.5%, leveling agent 0.5% 　 hydrocarbon-based solvent 10%, ETHER-based solvent 2.5%, alcohol-based solvent 5%, ketone-based solvent 5% and colorant 7% It is a silicone resin coated steel sheet having a coating thickness of 3㎛ prepared by painting a coating containing a.

Item Conventional example Inventive Example 2 Exterior 5 points 4 points Corrosion resistance reputation 5 points 5 points Processing 5 points 5 points Moisture resistance Type 5 points 5 points Lamination 5 points 5 points Chemical resistance alkali 5 points 5 points mountain 5 points 5 points Coefficient of friction 0.1 0.01 Film adhesion reputation 100/100 100/100 Processing 100/100 100/100 Anti-fingerprint 5 points 5 points Boiling water resistance 5 points 5 points

As shown in Table 2 above, the evaluation results for the items other than the friction coefficient show that they are equivalent. There was a difference in the friction coefficient, but this is a value that does not affect the actual use.

As described above, in the detailed description of the present invention, the preferred embodiments of the present invention have been described, but those skilled in the art to which the present invention pertains have various modifications within the limits that do not depart from the scope of the present invention. Of course this is possible. Therefore, the scope of rights of the present invention should not be limited to the described embodiments, but should be determined by the equivalents as well as the claims described later.

Claims (3)

In the CGL (Continuous Galvanized Line) process, the steel sheet, the bath temperature is 440 ~ 465 ℃, by weight Al: 1.1 ~ 1.7%, Mg: 1.1 ~ 1.7%, Zn: 96.6 ~ 97.8% and containing impurities Process of manufacturing a hot-dip galvanized steel sheet by continuously immersing in a hot dip galvanizing bath containing magnesium and then drying; And
A colored coating device, which is a post-treatment device, is installed at the rear end of the CGL process, and on the surface of the prepared hot-dip galvanized steel sheet, by weight, 0.5 to 5% of Si compound, 48 to 58 of water-soluble anionic urethane-acrylic copolymer resin %, Chromium reducing agent 0.3~5%, Chromium trioxide 0.2~5%, Fluorine-modified PE-based wax 1~5%, Pigment 1~10%, and the remaining coating water Method of manufacturing a high corrosion-resistant colored plated steel sheet using a CGL process comprising a.
The method of claim 1, wherein in the step of forming the colored coating layer, the colored coating solution is coated with an adhesion amount in the range of 1100 to 4000 mg/m 2, followed by drying to produce a highly corrosion-resistant colored plated steel sheet using a CGL process. Way.
The method according to claim 1, wherein the colored coating layer has a thickness of 1 to 4 μm.

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