Silicon carbide modified waterborne alkyd anticorrosive coating and method of making

Abstract

The application belongs to the technical field of anticorrosive coating and provides a silicon carbide modified waterborne alkyd resin anticorrosive coating and a preparation method thereof, a dense three-dimensional reinforcing network structure is constructed in the alkyd resin matrix by introducing silicon carbide particles and optimizing the synergic ratio of the silicon carbide particles, titanium dioxide and quartz powder fillers. The method effectively solves the problems of low hardness, poor medium resistance, uneven filler dispersion, weak interface bonding and difficulty in simultaneously improving mechanical and anticorrosive properties in the conventional physical filling modification due to low crosslinking density and many polar groups in the existing waterborne alkyd resin coating. The prepared coating has excellent comprehensive performance, the hardness can reach 2 H level, the gloss can reach 90%, the acid resistance, alkali resistance, salt water resistance and water resistance are significantly improved, and excellent electrochemical anticorrosive protection effect is exhibited on the metal matrix. The application is suitable for long-term anticorrosive protection of metal surfaces of steel structures, ships, bridges and the like, and has the characteristics of environmental protection and high performance.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, and relates to waterborne alkyd resin anti-corrosion coatings, specifically to a silicon carbide modified waterborne alkyd resin anti-corrosion coating and its preparation method. Background Technology

[0002] Metal corrosion is a major challenge and source of economic loss for the global industrial sector. Developing efficient and long-lasting protective coatings is a key strategy to address this problem. Among numerous coating systems, alkyd resins have long been widely used due to their readily available raw materials, controllable costs, and excellent overall coating performance. With increasingly stringent global environmental regulations and the deepening of sustainable development concepts, waterborne alkyd resin systems, using water as the dispersion medium, are rapidly replacing traditional solvent-based alkyd resins and becoming an important choice for anti-corrosion coating of large metal components such as ships, bridges, steel structures, and engineering machinery, thanks to their outstanding advantages such as extremely low volatile organic compound (VOC) emissions, non-toxic and odorless properties, safe construction, and environmental friendliness.

[0003] However, in the process of waterborne alkyd resins moving towards high-end anti-corrosion applications, their inherent molecular structure defects have become a technical bottleneck. To achieve water dispersibility, a high proportion of hydrophilic polar groups (such as hydroxyl and carboxyl groups) are usually introduced into the resin molecular chain. This causes the cured coating film to easily swell in humid or water-immersed environments, making water resistance and resistance to media penetration inherent weaknesses. At the same time, compared with solvent-based systems, the film-forming mechanism and crosslinking method of waterborne alkyd resins generally result in a lower crosslinking density in the final coating film, directly manifesting as insufficient surface hardness and poor wear resistance, making it difficult to meet the stringent requirements for mechanical strength and surface smoothness. These performance defects restrict the reliable application and promotion of waterborne alkyd resin coatings in high-end anti-corrosion scenarios such as heavy corrosion and high wear.

[0004] To address the above issues, existing technologies primarily explore two pathways: chemical modification and physical filling. The chemical modification pathway typically involves molecular design, copolymerizing or grafting high-performance resin monomers such as epoxy resins, polyurethanes, and acrylates, or using polyols and fatty acids with alkyd resins. This method aims to improve the resin's rigidity, crosslinking density, and chemical resistance. However, this pathway has significant limitations: First, the use of low-purity or structurally irregular polyols and fatty acids to control costs can easily lead to an excessively wide molecular weight distribution and uneven branching structure in the final resin product, potentially impairing the coating's density and gloss, making it difficult to form a uniform and efficient protective network. Second, complex copolymerization or polycondensation processes are often accompanied by harsh reaction conditions, long processes, and numerous byproducts, increasing overall production costs and posing significant challenges to process controllability.

[0005] On the other hand, the physical filling approach focuses on introducing inorganic fillers, such as nano-silica, titanium dioxide (titanium dioxide), and layered montmorillonite, into the resin matrix to improve coating performance through the reinforcement, toughening, and physical barrier effects of the fillers. This method is relatively simple, but the interfacial compatibility between traditional inorganic fillers and the organic resin matrix is ​​often poor. They are prone to agglomeration and uneven dispersion in the coating, forming stress defects that hinder their full enhancement potential. They may even become rapid channels for corrosive media penetration, resulting in limited improvements in the coating's long-term anti-corrosion performance, adhesion, and mechanical properties, thus failing to achieve breakthrough optimization.

[0006] Therefore, developing a new modification technology and material system that is simple to process, cost-controllable, and can fundamentally and synergistically improve the hardness, density, and long-term corrosion resistance of waterborne alkyd resin coatings has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to provide a silicon carbide-modified waterborne alkyd resin anti-corrosion coating and its preparation method. By introducing silicon carbide particles and optimizing their synergistic ratio with fillers such as titanium dioxide and quartz powder, a dense three-dimensional reinforced network structure is constructed in the alkyd resin matrix to solve the problems of insufficient hardness and poor media resistance (especially water resistance and acid and alkali resistance) caused by low crosslinking density and many polar groups in existing waterborne alkyd resin coatings.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: a silicon carbide modified waterborne alkyd resin anti-corrosion coating, wherein the anti-corrosion coating is prepared from waterborne alkyd resin, titanium dioxide, silicon carbide and quartz powder as raw materials.

[0009] Preferably, the mass ratio of titanium dioxide, silicon carbide and quartz powder is 1:3:1.

[0010] Preferably, the anti-corrosion coating has a hardness of not less than 2H and a gloss of 90%.

[0011] Preferably, the silicon carbide is of type 908C-600.

[0012] The present invention further provides a method for preparing the above-mentioned silicon carbide modified waterborne alkyd resin anti-corrosion coating.

[0013] Preferably, the steps include:

[0014] S1. Mix 3 g of neutralizing agent with 150 g of deionized water and stir for the first time; then add the excipients and 50 g of titanium dioxide and stir for the second time; finally add 150 g of silicon carbide and 50 g of quartz powder and stir for the third time to prepare a slurry.

[0015] S2. After filtering the above slurry through a 200-mesh filter cloth, add 2.5 g of deionized water, 187.5 g of base material and 93.75 g of emulsion in sequence, and stir for the fourth time; then add 4 g of flash rust agent and stir for the fifth time; finally add 5 g of thickener and stir for the sixth time to obtain the crude product.

[0016] S3. The above crude product is filtered a second time to obtain silicon carbide-waterborne alkyd resin composite slurry, which is then coated onto the surface of the substrate and cured to form the silicon carbide modified waterborne alkyd resin anti-corrosion coating.

[0017] Preferably, in step S1, the neutralizing agent is N,N-dimethylethanolamine, and the excipients consist of 4 g wetting and dispersing agent 565, 4 g wetting and dispersing agent 566, 2 g defoamer 611, 5 g wetting and leveling agent 610 and 7.5 g anti-settling agent 615; in step S2, the base material is waterborne alkyd resin, and the emulsion is waterborne acrylic emulsion.

[0018] Preferably, in step S1, the first stirring speed is 1000 r / min and the time is 10 min; the second stirring speed is 1000 r / min and the time is 10 min; the third stirring speed is 1600 r / min and the time is 30 min; in step S2, the fourth stirring speed is 1900 r / min and the time is 60 min; the fifth stirring speed is 1100 r / min and the time is 30 min; and the sixth stirring speed is 1300 r / min and the time is 30 min.

[0019] Preferably, in step S2, the flash rust agent is obtained by compounding nitrite and organic phosphate in a ratio of 1:2 to 1:5.

[0020] The present invention further provides the application of the above-mentioned silicon carbide modified waterborne alkyd resin anti-corrosion coating.

[0021] Preferably, the coating is applied to the surface of a metal product.

[0022] The beneficial effects of this invention are as follows: The introduction of silicon carbide can significantly improve the overall performance of waterborne alkyd resin composite coatings: on the one hand, it can effectively improve the hardness and gloss of the coating, and on the other hand, it can enhance the coating's resistance to corrosive media. This effect stems from the synergistic effect of silicon carbide and alkyd resin—the interaction between the two can refine the particle size of the coating, promoting the formation of a denser microstructure in the coating, thus laying a solid foundation for performance improvement. Attached Figure Description

[0023] Figure 1This invention relates to the effect of filler ratios on the hardness of waterborne alkyd resin composite coatings (a: titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; b: titanium dioxide: silicon carbide = 1:1.5; c: titanium dioxide: silicon carbide: quartz powder = 1:3:1; d: titanium dioxide: silicon carbide: barium sulfate = 1:3:1).

[0024] Figure 2 The effect of the silicon carbide-waterborne alkyd resin coating on acid resistance in this invention is shown in the following figures: (a) titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; (b) titanium dioxide: silicon carbide = 1:1.5; (c) titanium dioxide: silicon carbide: quartz powder = 1:3:1; (d) titanium dioxide: silicon carbide: barium sulfate = 1:3:1.

[0025] Figure 3 The effect of the silicon carbide-waterborne alkyd resin coating on the alkali resistance in this invention is shown in the following figures: (a) titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; (b) titanium dioxide: silicon carbide = 1:1.5; (c) titanium dioxide: silicon carbide: quartz powder = 1:3:1; (d) titanium dioxide: silicon carbide: barium sulfate = 1:3:1.

[0026] Figure 4 The effect of the silicon carbide-waterborne alkyd resin coating on salt water resistance in this invention is shown in the following figures: (a) titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; (b) titanium dioxide: silicon carbide = 1:1.5; (c) titanium dioxide: silicon carbide: quartz powder = 1:3:1; (d) titanium dioxide: silicon carbide: barium sulfate = 1:3:1.

[0027] Figure 5 The effect of the silicon carbide-waterborne alkyd resin coating on water resistance in this invention is shown in the following figures: (a) titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; (b) titanium dioxide: silicon carbide = 1:1.5; (c) titanium dioxide: silicon carbide: quartz powder = 1:3:1; (d) titanium dioxide: silicon carbide: barium sulfate = 1:3:1.

[0028] Figure 6 The effect of silicon carbide on the gloss of the waterborne alkyd resin composite coating in this invention is shown in the following figures: (a) titanium dioxide: barium sulfate: quartz powder = 1:0.5:1; (b) titanium dioxide: silicon carbide = 1:1.5; (c) titanium dioxide: silicon carbide: quartz powder = 1:3:1; (d) titanium dioxide: silicon carbide: barium sulfate = 1:3:1.

[0029] Figure 7 This invention relates to the effect of silicon carbide on the electrochemical performance of the waterborne alkyd resin composite coating after salt water resistance testing (a is the Nyquist plot of the alkyd resin composite coating; b is the Bode plot of the alkyd resin composite coating (impedance modulus test); c is the Bode plot of the alkyd resin composite coating (phase angle test); d is the Tafel polarization curve of the alkyd resin composite coating). Detailed Implementation

[0030] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0031] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example 1: Coating preparation and performance testing

[0034] 1. Materials and Methods

[0035] 1.1 Materials

[0036] N,N-Dimethylethanolamine, wetting and dispersing agent 565 (high molecular weight cationic wetting and dispersing agent, solid content: 50%), wetting and dispersing agent 566 (high molecular weight cationic wetting and dispersing agent, solid content: 40%), defoamer 611 (waterborne silicone defoamer emulsion, solid content: 15-20%), wetting and leveling agent 610 (waterborne silicone / acrylate wetting and leveling agent, solid content: 30-50%), and anti-settling agent 615 (hexamethyldisilazane hydrophobically modified fumed silica). Silicon), titanium dioxide (rutile type R), silicon carbide (light gray, 600 mesh, 908C-600), barium sulfate (1250 mesh, purity ≥98%), quartz powder (800 mesh, purity ≥96%-98%), base material (self-emulsifying waterborne alkyd resin, AK9504), emulsion (waterborne acrylic emulsion, DB3411-31), flash rust agent (a mixture of nitrite and organic phosphate ester in a ratio of 1:2 to 1:5), thickener (polyether type PU thickener).

[0037] 1.2 Preparation process

[0038] S1. While the mixer is stirring, add 3 g of neutralizing agent N,N-dimethylethanolamine and deionized water (self-made water from an ultrapure water system, 0.1-10 μS / cm), control the speed at 1000 r / min, and stir for 10 min. Then add 4 g of wetting and dispersing agent 565 (high molecular weight cationic wetting and dispersing agent, solid content: 50%), 4 g of wetting and dispersing agent 566 (high molecular weight cationic wetting and dispersing agent, solid content: 40%), 2 g of defoamer 611 (waterborne organosilicon defoamer emulsion, solid content: 15-20%), 5 g of wetting and leveling agent 610 (waterborne organosilicon / acrylate wetting and leveling agent, solid content: 30-50%), and 7.5 g of anti-settling agent 615 (hexamethyldisilazane hydrophobically modified fumed silica). Adjust the rotation speed to 1000 r / min, add an appropriate amount of titanium dioxide (rutile type R), stir for 10 min, then add silicon carbide (light gray, 600 mesh, 908C-600) and quartz powder (experimental group, 800 mesh, purity ≥96%-98%) in the corresponding proportions, titanium dioxide (50 g): silicon carbide (150 g): quartz powder (50 g) = 1:3:1. Use titanium dioxide (100 g): barium sulfate (50 g): quartz powder (100 g) = 1:0.5:1, titanium dioxide (100 g): silicon carbide (150 g) = 1:1.5, and titanium dioxide (50 g): silicon carbide (150 g): barium sulfate (50 g) = 1:3:1 as control groups for subsequent experiments. Then appropriately increase the rotation speed to 1600 r / min and stir for 30 min to form a uniform slurry.

[0039] S2. After completing the above steps, filter the slurry into the reaction vessel using a 200-mesh filter cloth. Add 2.5 g of deionized water (self-made water from an ultrapure water system, 0.1-10 μS / cm), 187.5 g of base material (self-emulsifying waterborne alkyd resin, AK9504), and 93.75 g of emulsion (waterborne acrylic emulsion, DB3411-31) to the filtered slurry, and stir at 1900 r / min for 60 min; then add 4 g of flash rust agent, and stir at 1100 r / min for 30 min; finally, add 5 g of thickener (polyether-type PU thickener) at a controlled speed of 1300 r / min, and stir for 30 min until uniformly mixed.

[0040] S3. After the paint is made, the slurry is filtered again to remove any impurities and undispersed particles, and finally a uniform and fine silicon carbide-waterborne alkyd resin composite slurry is obtained. The obtained slurry is then coated on the surface of the metal product. The specific operation is as follows: (1) Substrate treatment: The tinplate surface is sanded with sandpaper until it is bright and smooth, and residual metal debris and dust are removed to ensure that the surface is clean and free of impurities; (2) Slurry spraying: The paint is stirred evenly and sprayed evenly on the tinplate surface vertically with a high-pressure airless spray gun. The spraying distance is controlled (the distance between the spray gun and the tinplate is kept at 20-30 cm). After spraying, the tinplate is first placed in a humid environment at room temperature to air dry naturally for 24 h, and then placed in a 50 ℃ forced-air drying oven to dry for more than 30 h. After complete curing, subsequent performance tests are carried out.

[0041] 1.3 Performance Testing

[0042] (1) Hardness test method: Fix the coating sample on the pencil hardness test platform, ensuring that the sample surface is flat and level. Select a pencil and use a pencil sharpener to sharpen the lead into a cylinder with a length of about 3-5 mm. Then, grind the end face of the lead flat on sandpaper in a direction at a 90-degree angle to the axis of the lead. Install the pencil on a 45-degree fixed bracket, so that the pencil lead is at a 45-degree angle to the coating surface. Apply a constant pressure of (1±0.05) kg and rub forward on the coating surface at a speed of (0.5-1) cm / s for a rubbing length of 3-5 cm.

[0043] (2) Adhesion test method: Fix the coating sample on the test table, ensuring the sample surface is flat. Select an appropriate size crisscross cutter according to the coating thickness, and make perpendicular intersecting grid-like cuts on the coating surface. The cut depth should penetrate the coating to reach the substrate. The number of grids is usually 10×10, and the side length of each square is 1-3 mm (adjusted according to the coating thickness). Gently sweep away the debris at the cuts with a soft brush along the grid lines. Smoothly stick the tape on the grid area, press the tape firmly with your fingers to ensure that the tape is completely adhered to the coating surface, and hold for about 1-2 minutes. Then, quickly peel off the tape at a 45-degree angle to the coating surface.

[0044] (3) Gloss test method: Place the coating sample to be tested on a flat and stable test platform, ensuring that there are no interfering objects such as dust or stains on the sample surface. Adjust the multi-angle gloss meter and adjust the incident angle to 60 degrees for measurement.

[0045] (4) Acid and alkali resistance test method: The prepared coating sample was immersed in 10% sulfuric acid solution, 10% sodium hydroxide solution, salt water (5% NaCl) and deionized water respectively. The changes on the coating surface were observed and the surface phenomena were recorded.

[0046] (5) Electrochemical performance testing: The coating was tested using a three-electrode system with open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). A platinum sheet was used as the counter electrode, a saturated calomel electrode as the reference electrode, and a coated tinplate (test area 1.0 cm²) was used. 2 The electrode was a 5% NaCl solution, and the electrolyte was a 5% NaCl solution. First, a 30-minute OCP test was performed to stabilize the system; then, EIS measurements were performed (frequency range 10). 5 ~10 -2 Hz, AC amplitude 10 mV).

[0047] 2. Results Analysis

[0048] The silicon carbide used in this technology is 908C-600. The optimal overall coating performance is achieved when the mass ratio of titanium dioxide, silicon carbide, and quartz powder is 1:3:1. Compared to base slurry coatings without added silicon carbide, this formulation significantly improves the coating's resistance to various media.

[0049] like Figure 2 As shown, after soaking the samples in 10% sulfuric acid solution for 48 hours, the appearance of the paint film varied with different filler ratios, especially when the mass ratio of titanium dioxide:silicon carbide:quartz powder was 1:3:1. Figure 2 (c) The number of blistering on the paint film surface is the lowest (only 5). The above results indicate that the addition of silicon carbide can effectively improve the acid resistance of the metal coating, and the acid resistance of the metal coating is optimal when the mass ratio of titanium dioxide:silicon carbide:quartz powder is 1:3:1.

[0050] like Figure 3 As shown, after immersing the samples in a 10% sodium hydroxide solution for 30 minutes, the paint films with different filler ratios exhibited significant differences: when the mass ratio of titanium dioxide:barium sulfate:quartz powder was 1:0.5:1, a large number of dense blistering appeared in the paint film; however, after introducing silicon carbide into the filler system, the number of blistering in the paint film was significantly reduced, with the best effect and the fewest blistering on the paint film surface when the mass ratio of titanium dioxide:silicon carbide:quartz powder was 1:3:1. Figure 3 (c) The above phenomena indicate that the addition of silicon carbide can effectively enhance the alkali resistance of the coating.

[0051] like Figure 4 As shown, after immersing the samples in a 5% sodium chloride solution for 24 hours, the surface conditions of the paint film with different filler ratios showed significant differences: when the mass ratio of titanium dioxide:barium sulfate:quartz powder was 1:0.5:1, the paint film exhibited large-area corrosion and numerous blistering, but no obvious peeling; when the mass ratio of titanium dioxide:silicon carbide was 1:1.5, the amount of corrosion and blistering was significantly reduced; when the mass ratio of titanium dioxide:silicon carbide:quartz powder was 1:3:1, only a few rust spots appeared on the paint film surface, and the number of blistering was minimal; when the mass ratio of titanium dioxide:silicon carbide:barium sulfate was 1:3:1, although the paint film only showed small-area corrosion, it was accompanied by numerous blistering. In summary, adding silicon carbide to the metal coating can significantly improve its salt water resistance, and the coating exhibits the best salt water resistance when the mass ratio of titanium dioxide, silicon carbide, and quartz powder is controlled at 1:3:1.

[0052] like Figure 5 As shown, the water resistance and corrosion performance of the paint film varied significantly under different filler ratios. When the mass ratio of titanium dioxide:barium sulfate:quartz powder was 1:0.5:1, severe corrosion appeared at the edges of the paint film, accompanied by numerous blistering and significant peeling, resulting in the worst water resistance. When the mass ratio of titanium dioxide:silicon carbide:quartz powder was 1:3:1, the paint film showed the least corrosion—only a single rust spot appeared locally, and no blistering occurred, demonstrating the best water protection effect. In conclusion, silicon carbide has a significant effect on improving the water resistance of metal coatings.

[0053] In terms of physical properties, such as Figure 1 As shown, there are significant differences in the hardness grade of the coating film under different filler ratios: when the mass ratio of titanium dioxide:barium sulfate:quartz powder is 1:0.5:1, the hardness grade of the coating film is the lowest, only grade B; while when the mass ratio of titanium dioxide:silicon carbide:quartz powder is 1:3:1, the hardness grade of the coating film reaches the highest, grade 2H. This result indicates that the addition of silicon carbide can significantly improve the hardness of the alkyd resin composite coating, and the coating hardness is optimal when titanium dioxide, silicon carbide, and quartz powder are mixed in a mass ratio of 1:3:1. This phenomenon may be due to the superhard properties of silicon carbide itself. On the one hand, it can form a structural reinforcement effect with the coating system; on the other hand, it can form a strong interfacial bond with the alkyd resin matrix. Both of these factors jointly promote the densification of the microstructure of the composite coating, ultimately achieving a significant improvement in the coating hardness grade.

[0054] As shown in Figure 6, when the mass ratio of titanium dioxide to silicon carbide is 1:1.5, the average reflectivity of the sample is 60%; when the mass ratio of titanium dioxide, silicon carbide, and quartz powder is 1:3:1, the average reflectivity of the sample can reach up to 90%, with an improvement rate of about 50%. It can be seen that the addition of silicon carbide can significantly improve the gloss of the coating.

[0055] Based on the electrochemical impedance spectroscopy (EIS) and corrosion current data of the silicon carbide-waterborne alkyd resin composite coating, the influence of different filler ratios on the anti-corrosion performance of the coating can be systematically analyzed. As can be seen from the Nyquist spectrum (…), Figure 7 (a) When the mass ratio of titanium dioxide:silicon carbide:quartz powder is 1:3:1, the coating's capacitive arc radius reaches its maximum value, indicating that the salt water has the weakest corrosive effect on the sample and the best anti-corrosion effect under this ratio. The impedance modulus test results show ( Figure 7 (b) The coating with this formulation has the highest initial impedance modulus, reaching 9503 Ω. cm²; while the impedance modulus directly reflects the coating's resistance to charge transfer. A higher value indicates better coating structural integrity and more significant resistance to charge transfer at the coating / substrate interface, further confirming that this formulation provides the most stable corrosion protection. The phase angle spectrum shows that ( Figure 7 In the case of titanium dioxide, silicon carbide, and quartz powder in a mass ratio of 1:3:1, the phase angle decreases more gradually, the capacitance response is weaker, and the phase angle is closest to 0° in the low-frequency region (<10 Hz). This characteristic indicates that the coating has the highest resistance and the densest microstructure, effectively inhibiting the penetration and diffusion of corrosion ions and exhibiting the strongest corrosion resistance. Further verification was made using Tafel corrosion current data. Figure 7 (d) The iron sheet corrosion current of the sample with this ratio shows the most negative value—the more negative the corrosion current, the stronger the protective effect of the coating on the substrate. It can more effectively isolate the contact between the NaCl corrosion system and the iron sheet substrate, and significantly reduce the corrosion rate of the NaCl solution on the iron sheet, providing strong evidence for the excellent anti-corrosion performance of the coating.

[0056] In summary, the test results of electrochemical impedance spectroscopy and Tafel curve method corroborate each other, confirming that the composite coating with a mass ratio of titanium dioxide:silicon carbide:quartz powder of 1:3:1 has the highest impedance value, the lowest corrosion current density, and the best anti-corrosion protection effect on the metal substrate.

[0057] Based on the above experimental results, the optimization effect of appropriate silicon carbide on coating performance is mainly achieved through two pathways: first, it enhances the barrier properties of the coating, physically preventing corrosive media such as acids, alkalis, and salt solutions from penetrating to the coating-metal substrate interface; second, silicon carbide particles and alkyd resin matrix synergistically construct a special three-dimensional network structure, which not only enhances the coating hardness but also further densifies the microstructure, ultimately achieving a synergistic improvement in the physical properties and anti-corrosion performance of the coating.

[0058] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A silicon carbide-modified waterborne alkyd resin anti-corrosion coating, characterized in that, The anti-corrosion coating is prepared from water-based alkyd resin, titanium dioxide, silicon carbide and quartz powder.

2. The silicon carbide-modified waterborne alkyd resin anti-corrosion coating according to claim 1, characterized in that, The mass ratio of titanium dioxide, silicon carbide and quartz powder is 1:3:

1.

3. The silicon carbide-modified waterborne alkyd resin anti-corrosion coating according to claim 1, characterized in that, The anti-corrosion coating has a hardness of not less than 2 H and a gloss of 90%.

4. The silicon carbide-modified waterborne alkyd resin anti-corrosion coating according to claim 1, characterized in that, The silicon carbide is of type 908C-600.

5. The method for preparing the silicon carbide-modified waterborne alkyd resin anti-corrosion coating according to claim 1, characterized in that, Includes the following steps: S1. Mix 3 g of neutralizing agent with 150 g of deionized water and stir for the first time; then add the excipients and 50 g of titanium dioxide and stir for the second time; finally add 150 g of silicon carbide and 50 g of quartz powder and stir for the third time to prepare a slurry. S2. After filtering the above slurry through a 200-mesh filter cloth, add 2.5 g of deionized water, 187.5 g of base material and 93.75 g of emulsion in sequence, and stir for the fourth time; then add 4 g of flash rust agent and stir for the fifth time; finally add 5 g of thickener and stir for the sixth time to obtain the crude product. S3. The above crude product is filtered a second time to obtain silicon carbide-waterborne alkyd resin composite slurry, which is then coated onto the surface of the substrate and cured to form the silicon carbide modified waterborne alkyd resin anti-corrosion coating.

6. The preparation method according to claim 5, characterized in that, In step S1, the neutralizing agent is N,N-dimethylethanolamine, and the excipients consist of 4 g wetting and dispersing agent 565, 4 g wetting and dispersing agent 566, 2 g defoamer 611, 5 g wetting and leveling agent 610 and 7.5 g anti-settling agent 615; in step S2, the base material is waterborne alkyd resin, and the emulsion is waterborne acrylic emulsion.

7. The preparation method according to claim 5, characterized in that, In step S1, the first stirring speed is 1000 r / min and the time is 10 min; the second stirring speed is 1000 r / min and the time is 10 min; the third stirring speed is 1600 r / min and the time is 30 min. In step S2, the fourth stirring speed is 1900 r / min and the time is 60 min; the fifth stirring speed is 1100 r / min and the time is 30 min; the sixth stirring speed is 1300 r / min and the time is 30 min.

8. The preparation method according to claim 5, characterized in that, In step S2, the flash rust agent is obtained by compounding nitrite and organic phosphate in a ratio of 1:2 to 1:

5.

9. The application of the silicon carbide-modified waterborne alkyd resin anti-corrosion coating according to claim 1, characterized in that, The coating is used to coat the surface of metal products.

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