Production process of color steel plate
By using magnetically permeable metal paint in the production of colored steel plates and aligning it under the action of a magnetic field, the defect problem caused by the difficulty of volatilization of coating solvents is solved, and the gloss and material yield are improved.
Patent Information
- Application Number
- CN202411753335.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-03-04
AI Technical Summary
During the production process, the paint solvent is prone to evaporation on the edges of the steel plate, resulting in defects in the stacking and shrinkage holes, affecting the material yield.
The coating is carried out with magnetically permeable metal paint and arranged in an orderly and oriented manner under the action of a magnetic field parallel to the steel plate to reduce the aggregation and irregular movement of aluminum powder.
It improves the gloss of the paint surface, reduces the occurrence of defects, and improves the beauty and material yield of the product.
Smart Images
Figure BDA0005165549080000071 
Figure BDA0005165549080000081
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of steel plates, and in particular relates to a production process of colored steel plates. Background Art
[0002] Color-coated steel plate (PCM) is a product made of cold-rolled steel plate and galvanized steel plate as the substrate, which is subjected to surface pretreatment (degreasing, cleaning, chemical conversion treatment), coated with paint in a continuous method (roller coating method), and then baked and cooled. After long-term market research, PCM products are more cost-effective than VCM and glass products, and PCM products with decorative effects such as texture and pearlescent on the surface are becoming more and more popular in refrigerator door panels and side panels.
[0003] At present, the metallic paint of PCM products contains a large amount of aluminum powder pigment filler that produces metallic effect. The aluminum powder has a large particle size and is arranged in a disordered flake shape. When the paint gathers at the edge of the strip due to surface tension, the heating solvent is blocked by the aluminum powder and evaporates poorly. As a result, when the color-coated plate is produced, the paint solvent is not easy to evaporate at the edge of the steel plate, which will easily produce edge stacking and shrinkage defects at the edge. In severe cases, it will cause the edge coating to crack and fall off. This defect has also become the main problem affecting the yield rate of metallic paint color-coated products. Summary of the invention
[0004] The purpose of the present invention is to provide a production process for color steel plates, so as to overcome the problem of aggregation of metallic paint on the surface of color steel plates during coating and improve the glossiness of the color steel plates after painting.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] The present invention provides a production process of a colored steel plate, comprising the following steps:
[0007] Step 1: Pretreatment and passivation: Degrease and clean the galvanized steel sheet, wash it with water and air dry it, and use a passivation liquid to passivate the air-dried galvanized steel sheet to form a passivation film on the upper and lower surfaces;
[0008] Step 2: Applying primer and back paint: Applying polyester primer on the upper surface of the passivated galvanized steel sheet and back paint on the lower surface, forming a primer layer and a back paint layer after drying to obtain a prefabricated board;
[0009] Step 3: Apply metallic paint: Apply magnetic conductive metallic paint on the primer layer, apply a magnetic field parallel to the prefabricated board, the magnetic field action time is 1-2s, and a metal layer is formed after drying;
[0010] Commonly used metallic paints have fine aluminum particles added to their base. When light hits the aluminum particles, it is reflected through the paint film, creating a flashing effect. Therefore, it is also called metallic flash paint. However, during the evaporation of the solvent, some aluminum powder in the coating will drift, condense, and shift, forming an irregular arrangement. After light refraction, it will appear as a cloud, reducing the aesthetics. Magnetic metallic paint can be guided by the magnetic field to be arranged in an orderly and directional manner parallel to the prefabricated board, reducing irregular movement.
[0011] Step 4: embossing: after step 3, single-sided embossing is performed on the metal layer to form a texture layer by pressing the pattern;
[0012] Step 5: Laminating: After embossing is completed, a PE film is covered on the surface of the texture layer to protect the surface of the steel plate, form a PE layer, and obtain a colored steel plate.
[0013] Furthermore, the magnetic conductive metallic paint comprises the following raw materials in terms of mass fraction:
[0014] 1-8 parts of magnetic aluminum powder, 25-35 parts of acrylic resin, 6-12 parts of auxiliary agent, 20-30 parts of solvent, and 9-15 parts of cellulose acetate butyrate.
[0015] Furthermore, the preparation steps of the magnetic conductive metal paint are as follows:
[0016] Add magnetic aluminum powder to the solvent, stir at 100-300 r / min for 20-30 min, add acrylic resin and cellulose acetate butyrate after stirring, continue stirring and mixing at 500-800 r / min for 30-60 min, add auxiliary agent and stir and mix at 300-500 r / min for 10-20 min to obtain magnetic conductive metal paint.
[0017] Furthermore, the preparation steps of the magnetic aluminum powder are as follows:
[0018] The flaky aluminum powder is dispersed in a 30-60wt% ethanol aqueous solution at a concentration of 1-5g / mL, and sodium dodecyl sulfate is added to form a mixed solution. Under a constant temperature water bath at 30-60°C, a hexahydrate ferric chloride solution and a tetrahydrate ferrous chloride solution are added dropwise to the mixed solution at a molar ratio of 6-10:1 between the metal elements aluminum and iron. The ratio of the hexahydrate ferric chloride solution to the tetrahydrate ferrous chloride solution is based on the molar ratio of Fe 3+ :Fe 2+ =4:1-4, add ammonia water to control pH>10, continue stirring and react for 2-3h, cool and age for 2-6h after the reaction, filter and wash with deionized water until neutral, dry and calcine in a muffle furnace at 300-500℃ for 1-3h to obtain magnetic aluminum powder.
[0019] The flaky aluminum powder is used as a carrier, and ferroferric oxide is loaded on its surface by precipitation method. The reaction formula of precipitation is as follows:
[0020] Fe 2+ +2Fe 3+ +8NH3·H2O=Fe3O4↓+8NH4 + +4H2O.
[0021] Ferroferric oxide grows and precipitates on the surface of flaky aluminum powder. The magnetism of the aluminum powder loaded with ferroferric oxide is enhanced, and it can be oriented under the action of the magnetic field, so that the paint film has higher gloss, better sparkle effect and angle-dependent color effect.
[0022] Furthermore, the auxiliary agent is one of polyethylene wax and polyamide wax.
[0023] Furthermore, the solvent is at least one of butyl acetate, xylene and ethylene glycol butyl ether.
[0024] Furthermore, the mass concentration of sodium dodecyl sulfate in the mixed solution is 1-3%.
[0025] Furthermore, the concentration of the ferric chloride hexahydrate solution is 0.1-0.4 mol / L, and the concentration of the ferrous chloride tetrahydrate solution is 0.025-0.4 mol / L.
[0026] Furthermore, in step three, the magnetic field strength of the magnetic field is 10-20A / m. Under the action of a short-term weak magnetic field, the magnetic aluminum powder in the metallic paint can be orderly and directional arranged. If the time is too long, the magnetic aluminum powder will undergo a larger displacement movement with the action of the magnetic field, causing the magnetic aluminum powder on one side to aggregate. When the magnetic field strength is too high, the movement intensity of the magnetic aluminum powder increases, and a larger displacement movement will also occur in a short time, affecting the uniformity of the metal layer on the surface of the prefabricated board.
[0027] Furthermore, the thickness of the metal layer is 20-80 μm.
[0028] Beneficial effects of the present invention:
[0029] (1) In the production process of colored steel plates, the present invention uses magnetic metallic paint to coat the paint layer. Under the action of a magnetic field parallel to the steel plate, the magnetic metal powder in the magnetic metallic paint is oriented and orderly arranged, thereby reducing the aggregation of the metal powder and improving the glossiness of the paint surface. The process is simple.
[0030] (2) The combination of the flashing effect of metallic paint and the diversity of single-sided embossed texture enhances the technological sense and beauty of the product's appearance pattern, which can meet the design needs of different brands. DETAILED DESCRIPTION
[0031] 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.
[0032] Example 1
[0033] Preparation of magnetic aluminum powder:
[0034] Aluminum flake powder of 3-10 μm was dispersed in a 60 wt % ethanol aqueous solution at a concentration of 1 g / mL, and sodium dodecyl sulfate was added to form a mixed solution. The mass concentration of sodium dodecyl sulfate in the mixed solution was 1%. Under a constant temperature water bath at 50°C, 0.4 mol / L ferric chloride hexahydrate solution and 0.4 mol / L ferrous chloride tetrahydrate solution were added dropwise to the mixed solution at a molar ratio of 10:1 between the metal elements aluminum and iron. The ratio of the ferric chloride hexahydrate solution to the ferrous chloride tetrahydrate solution was 1:1. 3+ :Fe 2+ =4:4, add ammonia water to control pH>10, continue stirring and react for 2.5 hours, cool and age for 6 hours after the reaction, filter and wash with deionized water until neutral, dry and calcine in a muffle furnace at 300°C for 2 hours to obtain magnetic aluminum powder.
[0035] Preparation of magnetic metallic paint:
[0036] The raw materials were weighed according to the following mass parts: 1 part of magnetic aluminum powder, 25 parts of acrylic resin, 6 parts of polyethylene wax, 30 parts of butyl acetate, and 15 parts of cellulose acetate butyrate.
[0037] Add magnetic aluminum powder to butyl acetate, stir at 200 r / min for 25 min, add acrylic resin and cellulose acetate butyrate after stirring, continue stirring and mixing at 500 r / min for 60 min, add polyethylene wax and stir and mix at 500 r / min for 10 min to obtain magnetic conductive metal paint.
[0038] Preparation of colored steel plates:
[0039] Step 1, pretreatment and passivation: the galvanized steel sheet is degreased and cleaned, washed with water and air-dried, and the air-dried galvanized steel sheet is passivated with a passivation liquid (BONDERITE M-NT 2040 chromium-free passivator) to form a passivation film on the upper and lower surfaces;
[0040] Step 2: Applying primer and back paint: Applying polyester primer on the upper surface of the passivated galvanized steel sheet and back paint on the lower surface, forming a primer layer and a back paint layer after drying to obtain a prefabricated board;
[0041] Step 3: Applying metallic paint: Applying magnetic conductive metallic paint on the primer layer, applying a magnetic field with a magnetic field strength of 10A / m parallel to the prefabricated board for 2 seconds, and forming a 60μm metal layer after drying;
[0042] Step 4: embossing: after step 3, single-sided embossing is performed on the metal layer to form a texture layer by pressing the pattern;
[0043] Step 5: Laminating: After embossing is completed, a PE film is covered on the surface of the texture layer to protect the surface of the steel plate, form a PE layer, and obtain a colored steel plate.
[0044] Example 2
[0045] The only difference from Example 1 is that in the step of preparing magnetic aluminum powder, 0.4 mol / L ferric chloride hexahydrate solution and 0.4 mol / L ferrous chloride tetrahydrate solution are added dropwise to the mixed solution according to the molar ratio of metal elements aluminum and iron being 8:1, and the other conditions and steps are the same as those in Example 1.
[0046] Example 3
[0047] The only difference from Example 1 is that in the step of preparing magnetic aluminum powder, 0.4 mol / L ferric chloride hexahydrate solution and 0.4 mol / L ferrous chloride tetrahydrate solution are added dropwise to the mixed solution according to the molar ratio of metal elements aluminum and iron being 6:1, and the other conditions and steps are the same as those in Example 1.
[0048] Example 4
[0049] The only difference from Example 2 is that the mass fraction of magnetic aluminum powder in the raw material is adjusted to 6 parts when preparing the magnetic metallic paint, and the other conditions and steps are the same as Example 2.
[0050] Example 5
[0051] The only difference from Example 2 is that the mass fraction of magnetic aluminum powder in the raw material is adjusted to 8 parts when preparing the magnetic conductive metallic paint, and the other conditions and steps are the same as Example 2.
[0052] Example 6
[0053] The only difference from Example 4 is that the magnetic field intensity in step three of preparing the colored steel plate is adjusted to 15 A / m, and the other conditions and steps are the same as Example 4.
[0054] Example 7
[0055] The only difference from Example 4 is that the magnetic field intensity in step three of preparing the colored steel plate is adjusted to 20 A / m, and the other conditions and steps are the same as Example 4.
[0056] Example 8
[0057] The only difference from Example 7 is that the time of magnetic field action in step three of preparing the colored steel plate is adjusted to 1.5 s, and the other conditions and steps are the same as Example 7.
[0058] Example 9
[0059] The only difference from Example 7 is that the time of magnetic field action in step three of preparing the colored steel plate is adjusted to 1 s, and the other conditions and steps are the same as Example 7.
[0060] Example 10
[0061] The only difference from Example 9 is that the mass fractions of the raw materials are different when preparing the magnetic conductive metallic paint. The specific mass fractions are as follows:
[0062] 6 parts of magnetic aluminum powder, 30 parts of acrylic resin, 10 parts of polyethylene wax, 25 parts of butyl acetate, and 11 parts of cellulose acetate butyrate.
[0063] Other conditions and steps are the same as in Example 9.
[0064] Embodiment 11
[0065] The only difference from Example 9 is that the mass fractions of the raw materials are different when preparing the magnetic conductive metallic paint. The specific mass fractions are as follows:
[0066] 6 parts of magnetic aluminum powder, 35 parts of acrylic resin, 12 parts of polyethylene wax, 20 parts of butyl acetate, and 9 parts of cellulose acetate butyrate.
[0067] Other conditions and steps are the same as in Example 9.
[0068] Comparative Example 1
[0069] Compared with Example 1, ordinary metallic paint is used in this comparative example to replace the magnetic metallic paint, no magnetic field is applied in step three of preparing the colored steel plate, and the step of preparing the magnetic aluminum powder is omitted.
[0070] Preparation of metallic paint:
[0071] The raw materials were weighed according to the following mass parts: 1 part of aluminum powder, 25 parts of acrylic resin, 6 parts of polyethylene wax, 30 parts of butyl acetate, and 15 parts of cellulose acetate butyrate.
[0072] Aluminum powder was added to butyl acetate, and the mixture was stirred at 200 r / min for 25 min. After stirring, acrylic resin and cellulose acetate butyrate were added, and the mixture was continuously stirred at 500 r / min for 60 min. Polyethylene wax was added, and the mixture was stirred at 500 r / min for 10 min to obtain metallic paint.
[0073] Preparation of colored steel plates:
[0074] Step 1, pretreatment and passivation: the galvanized steel sheet is degreased and cleaned, washed with water and air-dried, and the air-dried galvanized steel sheet is passivated with a passivation liquid (BONDERITE M-NT 2040 chromium-free passivator) to form a passivation film on the upper and lower surfaces;
[0075] Step 2: Applying primer and back paint: Applying polyester primer on the upper surface of the passivated galvanized steel sheet and back paint on the lower surface, forming a primer layer and a back paint layer after drying to obtain a prefabricated board;
[0076] Step 3: Apply metallic paint: Apply metallic paint on the primer layer and form a 60 μm metal layer after drying;
[0077] Step 4: embossing: after step 3, single-sided embossing is performed on the metal layer to form a texture layer by pressing the pattern;
[0078] Step 5: Laminating: After embossing is completed, a PE film is covered on the surface of the texture layer to protect the surface of the steel plate, form a PE layer, and obtain a colored steel plate.
[0079] The performance of the color steel plates prepared in Examples 1 to 11 and Comparative Example 1 was tested, and the results are shown in Table 1.
[0080] The glossiness test is conducted in accordance with GBT12754-2006 Color Coated Steel Sheets and Strips.
[0081] Table 1
[0082]
[0083]
[0084] As can be seen from Table 1, compared with Example 1, Example 2 reduces the molar ratio of aluminum to iron, increases the loading amount of ferroferric oxide on the aluminum powder, and under the same magnetic field conditions, the accumulation of aluminum powder is reduced, and the surface glossiness of the prepared steel plate is higher. The excessive loading amount in Example 3 causes ferroferric oxide to completely cover the aluminum powder, which has a covering effect and reduces the flash effect of the aluminum powder. On the basis of Example 2, Examples 4 and 5 increase the proportion of magnetic aluminum powder in the magnetic conductive metal paint, and the glossiness of the steel plate is improved. Examples 6 and 7 enhance the magnetic field strength, and Examples 8 and 9 shorten the action time. Among them, under the conditions of magnetic field strength and action time of Example 9, the glossiness of the steel plate is optimal. Due to the disordered arrangement and accumulation phenomenon in the coating of the metal paint, the glossiness of the colored steel plate in Comparative Example 1 is far inferior to that of Example 1.
[0085] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0086] 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 production process for colored steel plates, characterized in that: The following steps are involved: Step 1: Pretreatment and passivation: Degrease and clean the galvanized steel sheet, wash it with water and air dry it, and use a passivation liquid to passivate the air-dried galvanized steel sheet to form a passivation film on the upper and lower surfaces; Step 2: Applying primer and back paint: Applying polyester primer on the upper surface of the passivated galvanized steel sheet and back paint on the lower surface, forming a primer layer and a back paint layer after drying to obtain a prefabricated board; Step 3: Apply metallic paint: Apply magnetic conductive metallic paint on the primer layer, apply a magnetic field parallel to the prefabricated board, the magnetic field action time is 1-2s, and a metal layer is formed after drying; Step 4: embossing: after step 3, single-sided embossing is performed on the metal layer to form a texture layer by pressing the pattern; Step 5: Laminating: After embossing is completed, a PE film is covered on the surface of the texture layer to protect the surface of the steel plate, form a PE layer, and obtain a colored steel plate.
2. The production process of a colored steel plate according to claim 1, characterized in that: The magnetic conductive metal paint comprises the following raw materials in parts by mass: 1-8 parts of magnetic aluminum powder, 25-35 parts of acrylic resin, 6-12 parts of auxiliary agent, 20-30 parts of solvent, and 9-15 parts of cellulose acetate butyrate.
3. The production process of a colored steel plate according to claim 2, characterized in that: The preparation steps of the magnetic conductive metallic paint are as follows: Add magnetic aluminum powder to the solvent, stir at 100-300 r / min for 20-30 min, add acrylic resin and cellulose acetate butyrate after stirring, continue stirring and mixing at 500-800 r / min for 30-60 min, add auxiliary agent and stir and mix at 300-500 r / min for 10-20 min to obtain magnetic conductive metal paint.
4. The production process of a colored steel plate according to claim 2, characterized in that: The preparation steps of the magnetic aluminum powder are as follows: The flaky aluminum powder is dispersed in a 30-60wt% ethanol aqueous solution at a concentration of 1-5g / mL, and sodium dodecyl sulfate is added to form a mixed solution. Under a constant temperature water bath at 30-60°C, a hexahydrate ferric chloride solution and a tetrahydrate ferrous chloride solution are added dropwise to the mixed solution at a molar ratio of 6-10:1 between the metal elements aluminum and iron. The ratio of the hexahydrate ferric chloride solution to the tetrahydrate ferrous chloride solution is based on the molar ratio of Fe 3+ :Fe 2+ =4:1-4, add ammonia water to control pH>10, continue stirring and react for 2-3h, cool and age for 2-6h after the reaction, filter and wash with deionized water until neutral, dry and calcine in a muffle furnace at 300-500℃ for 1-3h to obtain magnetic aluminum powder.
5. The production process of a colored steel plate according to claim 4, characterized in that: The mass concentration of sodium dodecyl sulfate in the mixed solution is 1-3%.
6. The production process of a colored steel plate according to claim 4, characterized in that: The concentration of the ferric chloride hexahydrate solution is 0.1-0.4 mol / L, and the concentration of the ferrous chloride tetrahydrate solution is 0.025-0.4 mol / L.
7. The production process of a colored steel plate according to claim 2, characterized in that: The auxiliary agent is one of polyethylene wax and polyamide wax.
8. The production process of a colored steel plate according to claim 2, characterized in that: The solvent is at least one of butyl acetate, xylene and ethylene glycol butyl ether.
9. The production process of a colored steel plate according to claim 1, characterized in that: In step three, the magnetic field strength of the magnetic field is 10-20A / m.
10. The production process of a colored steel plate according to claim 1, characterized in that: The thickness of the metal layer is 20-80 μm.