A method for preparing a cured coating on a coiled steel surface

Abstract

The invention relates to the technical field of steel coil coating, and discloses a method for preparing a cured coating on the surface of a steel coil, comprising the following specific method steps: S1 raw material preparation, S2 coating preparation, S3 steel coil surface treatment, S4 electron beam cured coating and S5 post-treatment. The method can be cured efficiently and quickly: electron beam curing is adopted, and the coating can be cured in a very short time. Compared with traditional thermal curing, the curing time can be shortened from several hours to several seconds, which greatly improves the production efficiency and is suitable for large-scale continuous production of steel coil coating. At the same time, low energy consumption and environmental protection are achieved: the electron beam curing process does not need to maintain a high temperature environment for a long time like thermal curing, and energy consumption is significantly reduced. At the same time, waste gas emissions caused by high temperature are reduced, which meets environmental protection requirements and reduces the energy cost and environmental pressure of enterprises. The method has excellent coating performance: by accurately controlling parameters such as the energy and dosage of the electron beam, the coating can be cured evenly and fully, and the coating has high hardness and strong adhesion.

Description

Technical Field

[0001] The invention relates to the technical field of coil steel coatings, in particular to a method for preparing a cured coating on the surface of a coil steel. Background Art

[0002] Coiled steel is widely used in many industries such as construction, automobile manufacturing, and home appliances. Its surface coating is crucial to protecting the coiled steel substrate, improving corrosion resistance and decorativeness. Traditional methods for curing coiled steel coatings mainly include thermal curing and UV curing. Thermal curing requires a high temperature and a long curing time, which not only consumes a lot of energy, but also may cause the coiled steel to deform at high temperatures, thereby reducing product quality. Although UV curing is relatively energy-saving, it has limited curing depth and poor curing effect on the surface of coiled steel with complex shapes. With the rapid development of industry, higher requirements are placed on the quality, efficiency and environmental protection of coiled steel coatings. Therefore, it is urgent to seek an efficient, high-quality and environmentally friendly method for preparing coiled steel surface cured coatings. Electron beam curing technology, as an emerging curing method, has unique advantages and can largely overcome the shortcomings of traditional curing methods, providing new solutions for the preparation of coiled steel coatings. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a method for preparing a cured coating on the surface of a steel coil, which has the advantages of high efficiency, high quality and environmental protection. It solves the problems that traditional methods for curing steel coil coatings mainly include thermal curing and ultraviolet light curing. Thermal curing requires a high temperature and a long curing time, which not only consumes a lot of energy, but also may cause the steel coil to deform at high temperatures, thereby reducing product quality. Although ultraviolet light curing is relatively energy-saving, it has the problems of limited curing depth and poor curing effect on the surface of steel coils with complex shapes.

[0004] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a method for preparing a cured coating on the surface of a coiled steel, characterized in that it comprises the following specific method steps: S1 raw material preparation: High-performance epoxy resin is used as the basic film-forming material, with an epoxy equivalent of 180-220g / mol, to ensure that the coating has good adhesion and mechanical properties; Use active diluents, such as 1,6-hexanediol diglycidyl ether, at a dosage of 10% -15% of the epoxy resin mass to adjust the system viscosity for subsequent construction; S2 coating preparation: Stir the epoxy resin and active diluent in a high-speed stirrer at a speed of 800 - 1000r / min for 15 - 20 minutes to fully mix them; S3 Coil Surface Treatment: Use alkaline degreasing agent to degrease the surface of the coil, the concentration of the degreasing agent is 3% - 5%, the treatment temperature is 50 - 60℃, the treatment time is 3 - 5 minutes, and the surface oil is removed; For pickling and rust removal, use a 10% - 15% hydrochloric acid solution at room temperature for 2 - 3 minutes to remove surface rust and oxide layer; Rinse the surface of the coil with clean water, and then perform phosphating treatment, using zinc-based phosphating solution; After phosphating, rinse with clean water again and blow dry with hot air to make the surface of the coil dry and free of water stains; S4 electron beam cured coating: The prepared coating is evenly applied on the surface of the coil by roller coating, and the coating thickness is controlled at 20-30μm; Immediately after coating, the coil is fed into an electron accelerator for electron beam curing; S5 post-processing: Carry out quality inspection on the cured coiled steel to check whether the appearance of the coating is flat and smooth, without bubbles, sagging and other defects. Use a hardness tester to test the hardness of the coating, which should be between 2H and 3H. Use an adhesion tester to test the adhesion of the coating, and the adhesion level is required to be no less than level 1.

[0005] Preferably, the S1 raw material preparation: according to the required coating performance, functional fillers such as nano titanium dioxide can be added in appropriate amounts, with the particle size controlled at 20-50nm and the added amount being 5%-10% of the total mass of the resin system, to enhance the weather resistance and hardness of the coating.

[0006] Preferably, the surface treatment of the S3 steel coil has a total acidity of 20-30 points and a free acidity of 0.8-1.2 points, and is treated at 55-65°C for 3-5 minutes to form a phosphate film to enhance the adhesion of the coating.

[0007] Preferably, for the S4 electron beam cured coating, the energy of the electron accelerator is set to 200keV, the beam intensity is 50-100mA, the irradiation width is 140cm, and the radiation dose of the electron beam is 50-80kGy, so that the coating is quickly cured into a film under the action of the electron beam.

[0008] Preferably, in the post-processing step S5, the qualified coiled steel is packaged, and the packaging materials are moisture-proof and rust-proof plastic films and corrugated paperboards to ensure that the coating of the coiled steel is not damaged during transportation and storage.

[0009] Preferably, the S2 coating is formulated to control the viscosity of the coating to 80 - 120s (coating - 4 cups).

[0010] (III) Beneficial effects Compared with the prior art, the present invention provides a method for preparing a cured coating on the surface of a coiled steel, which has the following beneficial effects: 1. The preparation method of the cured coating on the surface of the coiled steel, which can be cured efficiently and quickly: the electron beam curing is adopted, and the coating can be cured in a very short time. Compared with the traditional thermal curing, the curing time can be shortened from several hours to several seconds, which greatly improves the production efficiency and is suitable for large-scale continuous production of coiled steel coating, while achieving low energy consumption and environmental protection: the electron beam curing process does not need to maintain a high temperature environment for a long time like thermal curing, and the energy consumption is significantly reduced. At the same time, the waste gas emission caused by high temperature is reduced, which meets the environmental protection requirements and reduces the energy cost and environmental pressure of the enterprise.

[0011] 2. A method for preparing a cured coating on the surface of the steel coil, which has excellent coating performance: by precisely controlling parameters such as the energy and dosage of the electron beam, the coating can be cured evenly and fully, and the coating has high hardness and strong adhesion. The hardness can reach 2H-3H, and the adhesion level is not less than level 1, which effectively improves the wear resistance, corrosion resistance and weather resistance of the steel coil and extends the service life of the steel coil.

[0012] 3. A method for preparing the cured coating on the surface of the coiled steel, which can ensure good adaptability: electron beam curing is not limited by the color and shape of the coating, and can achieve good curing effects for coiled steel surfaces with complex shapes or coatings with different color formulas, thereby broadening the application scope and design freedom of the coiled steel coating.

[0013] 4. A method for preparing the cured coating on the surface of the coiled steel, which reduces coating defects: Since the electron beam curing reaction is rapid and uniform, it can effectively reduce the generation of defects such as bubbles and sagging in the coating, improve the appearance quality and flatness of the coating, and enhance the market competitiveness of the product. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] This solution provides a technical solution, specifically, a method for preparing a cured coating on a coil surface, comprising the following specific method steps: S1 raw material preparation: High-performance epoxy resin is used as the basic film-forming material, with an epoxy equivalent of 180-220g / mol, to ensure that the coating has good adhesion and mechanical properties; Use active diluents, such as 1,6-hexanediol diglycidyl ether, at a dosage of 10% -15% of the epoxy resin mass to adjust the system viscosity for subsequent construction; According to the required coating performance, functional fillers such as nano titanium dioxide can be added in appropriate amounts, with the particle size controlled at 20-50nm and the addition amount being 5%-10% of the total mass of the resin system, to enhance the weather resistance and hardness of the coating; S2 coating preparation: Stir the epoxy resin and active diluent in a high-speed stirrer at a speed of 800-1000r / min for 15-20 minutes to fully mix them and control the viscosity of the coating at 80-120s (apply - 4 cups); S3 Coil Surface Treatment: Use alkaline degreasing agent to degrease the surface of the coil, the concentration of the degreasing agent is 3% - 5%, the treatment temperature is 50 - 60℃, the treatment time is 3 - 5 minutes, and the surface oil is removed; For pickling and rust removal, use a 10% - 15% hydrochloric acid solution at room temperature for 2 - 3 minutes to remove surface rust and oxide layer; Rinse the surface of the coil with clean water, and then perform phosphating treatment. The phosphating solution uses zinc phosphating solution with a total acidity of 20-30 points and a free acidity of 0.8-1.2 points. Treat at 55-65℃ for 3-5 minutes to form a phosphating film to enhance the adhesion of the coating. After phosphating, rinse with clean water again and blow dry with hot air to make the surface of the coil dry and free of water stains; S4 electron beam cured coating: The prepared coating is evenly applied on the surface of the coil by roller coating, and the coating thickness is controlled at 20-30μm; Immediately after coating, the steel coil is sent to an electron accelerator for electron beam curing. The energy of the electron accelerator is set to 200keV, the beam intensity is 50-100mA, the irradiation width is 140cm, and the radiation dose of the electron beam is 50-80kGy, so that the coating is quickly cured into a film under the action of the electron beam; S5 post-processing: Conduct quality inspection on the cured coiled steel to check whether the coating is smooth and has no defects such as bubbles and sagging. Use a hardness tester to test the hardness of the coating, which should be between 2H and 3H. Use an adhesion tester to test the adhesion of the coating, which is required to be no less than level 1. The qualified coils are packaged using moisture-proof and rust-proof plastic films and corrugated cardboard to ensure that the coating of the coils is not damaged during transportation and storage.

[0016] Furthermore, this method can cure quickly and efficiently: electron beam curing can cure the coating in a very short time. Compared with traditional thermal curing, the curing time can be shortened from several hours to several seconds, which greatly improves production efficiency and is suitable for large-scale continuous production of coiled steel coatings. It also achieves low energy consumption and environmental protection: the electron beam curing process does not need to maintain a high temperature environment for a long time like thermal curing, and energy consumption is significantly reduced. At the same time, it reduces waste gas emissions caused by high temperature, meets environmental protection requirements, and reduces the company's energy costs and environmental pressure.

[0017] Furthermore, this method has excellent coating performance: by precisely controlling parameters such as the energy and dosage of the electron beam, the coating can be cured evenly and fully, with high hardness and strong adhesion. The hardness can reach 2H - 3H, and the adhesion level is not less than level 1, which effectively improves the wear resistance, corrosion resistance and weather resistance of the steel coil and extends the service life of the steel coil.

[0018] Furthermore, this method can ensure good adaptability: electron beam curing is not limited by the color and shape of the coating, and can achieve good curing effects on complex-shaped coil surfaces or coatings with different color formulas, broadening the application range and design freedom of coil coatings.

[0019] Furthermore, the method reduces coating defects: since the electron beam curing reaction is rapid and uniform, it can effectively reduce the generation of defects such as bubbles and sagging in the coating, improve the appearance quality and smoothness of the coating, and enhance the market competitiveness of the product.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a cured coating on a coiled steel surface, characterized in that: The method includes the following specific steps: S1 raw material preparation: High-performance epoxy resin is used as the basic film-forming material, with an epoxy equivalent of 180-220g / mol, to ensure that the coating has good adhesion and mechanical properties; Use active diluents, such as 1,6-hexanediol diglycidyl ether, at a dosage of 10% -15% of the epoxy resin mass to adjust the system viscosity for subsequent construction; S2 coating preparation: Stir the epoxy resin and the active diluent in a high-speed stirrer at a speed of 800 - 1000 r / min for 15 - 20 minutes to fully mix them; S3 Coil Surface Treatment: Use alkaline degreasing agent to degrease the surface of the coil, the concentration of the degreasing agent is 3% - 5%, the treatment temperature is 50 - 60℃, the treatment time is 3 - 5 minutes, and the surface oil stains are removed; For pickling and rust removal, use a 10% - 15% hydrochloric acid solution at room temperature for 2 - 3 minutes to remove surface rust and oxide layer; Rinse the surface of the coil with clean water, and then perform phosphating treatment, using zinc-based phosphating solution; After phosphating treatment, rinse with clean water again and blow dry with hot air to make the surface of the coil dry and free of water stains; S4 electron beam cured coating: The prepared coating is evenly applied on the surface of the coil by roller coating, and the coating thickness is controlled at 20-30μm; Immediately after coating, the coil is fed into an electron accelerator for electron beam curing; S5 post-processing: Carry out quality inspection on the cured coiled steel to check whether the appearance of the coating is flat and smooth, without bubbles, sagging and other defects. Use a hardness tester to test the hardness of the coating, which should be between 2H and 3H. Use an adhesion tester to test the adhesion of the coating, and the adhesion level is required to be no less than level 1.

2. The method for preparing a cured coating on a coiled steel surface according to claim 1, characterized in that: The S1 raw material preparation: according to the required coating performance, functional fillers such as nano titanium dioxide can be added in appropriate amounts, with the particle size controlled at 20-50nm and the addition amount being 5%-10% of the total mass of the resin system, to enhance the weather resistance and hardness of the coating.

3. The method for preparing a cured coating on a coiled steel surface according to claim 1, characterized in that: The surface treatment of the S3 steel coil has a total acidity of 20 - 30 points and a free acidity of 0.8 - 1.2 points, and is treated at 55 - 65°C for 3 - 5 minutes to form a phosphate film and enhance the adhesion of the coating.

4. The method for preparing a cured coating on a coiled steel surface according to claim 1, characterized in that: For the S4 electron beam cured coating, the energy of the electron accelerator is set to 200keV, the beam intensity is 50-100mA, the irradiation width is 140cm, and the radiation dose of the electron beam is 50-80kGy, so that the coating is quickly cured into a film under the action of the electron beam.

5. The method for preparing a cured coating on a coiled steel surface according to claim 1, characterized in that: The S5 post-processing is to package the qualified coils, and the packaging materials are moisture-proof and rust-proof plastic films and corrugated paperboards to ensure that the coating of the coils is not damaged during transportation and storage.

6. The method for preparing a cured coating on a coiled steel surface according to claim 1, characterized in that: The S2 coating is formulated to control the coating viscosity at 80 - 120s (coating - 4 cups).