An epoxy bacteriostatic anticorrosive coating and a preparation method thereof

Abstract

The present application belongs to the technical field of anticorrosive paint, and particularly relates to an epoxy bacteriostatic anticorrosive paint and a preparation method thereof. The composition comprises the following components: bisphenol A type liquid epoxy resin, epoxy-terminated polysiloxane, core-shell rubber toughening agent, glass flake, surface-modified nano-silicon dioxide, gamma-glycidyl ether oxypropyl trimethoxysilane, reactive silane quaternary ammonium salt, latent imidazole curing agent, dispersant, defoaming agent, leveling agent and organic solvent. The present application forms a functionally graded structure with a surface layer rich in silicon for bacteriostasis and an epoxy anticorrosive bottom through multi-component synergistic design and step-by-step dispersion process; the glass flake and modified nano-silicon dioxide synergistically improve the barrier density, the core-shell rubber toughening agent enhances the film layer crack toughness, the reactive silane quaternary ammonium salt realizes long-term bacteriostasis without damaging the film layer structure, and the latent imidazole curing agent ensures the storage stability of the system.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, specifically relating to an epoxy antibacterial and anti-corrosion coating and its preparation method. Background Technology

[0002] Epoxy resin coatings are widely used in the protection of metal substrates due to their high adhesion, mechanical strength, chemical resistance, and corrosion resistance. Existing epoxy anti-corrosion coatings typically rely on the cross-linked network formed after curing to block moisture, oxygen, and corrosive ions, thus providing a shielding protection effect. However, existing epoxy coatings still have some shortcomings. First, cured epoxy resins are often brittle and sensitive to humid and hot environments. During long-term service, they are prone to microcracks due to water absorption, internal stress accumulation, or external loads, thereby weakening the shielding performance and interfacial adhesion stability of the film. Second, epoxy coatings have relatively limited resistance to ultraviolet aging. Under the combined effects of ultraviolet radiation and moisture, they are prone to surface failure phenomena such as yellowing, chalking, cracking, and peeling, thus affecting their long-term protective effect.

[0003] To impart antibacterial properties to epoxy coatings, existing technologies typically employ approaches such as metal or metal oxide antibacterial particles, quaternary ammonium salt antibacterial components, and antibacterial polymers. Based on their mechanism of action, existing antibacterial surfaces mainly include release-type, contact-killing type, and bacterial adhesion-inhibiting type. While release-type systems can provide antibacterial activity for a certain period, they are prone to problems such as active component migration, release rate attenuation, and insufficient long-term stability. If metal or inorganic nanoparticles are not sufficiently dispersed, they may aggregate, leading to increased local defects in the film layer and adversely affecting mechanical properties, shielding performance, and durability. In contrast, contact-killing quaternary ammonium salt surfaces, because their antibacterial groups can be fixed to the material surface, are generally more conducive to maintaining a longer-lasting antibacterial effect and reducing adverse effects on the physical and mechanical properties of the carrier material. Meanwhile, single-component epoxy systems have attracted attention due to their ease of application, avoidance of on-site mixing errors, and convenience for packaging and transportation; however, the key lies in the rational construction of the latent curing system. While existing single-component epoxy latent curing systems can maintain a certain level of storage stability at room temperature and achieve curing under heating conditions, they still face challenges in balancing storage stability, curing trigger temperature, filler dispersion, and overall post-curing performance. Especially when antibacterial components and preservative fillers are introduced simultaneously, insufficient compatibility between components, weak interfacial bonding, or improper addition order can easily lead to increased film brittleness, decreased density, insufficient antibacterial durability, or reduced preservative performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an epoxy antibacterial and anticorrosive coating and its preparation method, thereby solving the problems of difficulty in synergistic effects between antibacterial and anticorrosive components, easy embrittlement of the film layer, insufficient long-term shielding and protective stability, limited surface weather resistance, and difficulty in balancing the storage stability and subsequent curing performance of single-component systems in existing epoxy antibacterial and anticorrosive coatings.

[0005] The technical effects described in this invention are achieved through the following technical solution: an epoxy antibacterial and anti-corrosion coating, comprising the following components by weight: 48-55 parts of bisphenol A type liquid epoxy resin, 8-12 parts of epoxy-terminated polysiloxane, 5-8 parts of core-shell rubber toughening agent, 14-18 parts of glass flakes, 1.2-2 parts of surface-modified nano silica, 0.8-1.4 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.4-0.8 parts of reactive silane quaternary ammonium salt, 3.5-6 parts of latent imidazole curing agent, 0.3-0.6 parts of dispersant, 0.1-0.3 parts of defoamer, 0.1-0.3 parts of leveling agent, and 6-10 parts of organic solvent; Preferably, the core-shell rubber toughening agent is a core-shell elastomer particle with polybutadiene rubber as the core and polymethyl methacrylate as the shell, and its average particle size is 150-300 nm. The core-shell rubber toughening agent can be prepared by conventional emulsion polymerization in the art, that is, firstly, butadiene monomer is emulsion polymerized to form a rubber core emulsion, then methyl methacrylate is grafted onto its outer layer to form a shell layer, and finally, after coagulation, washing and drying, a powdered core-shell rubber toughening agent is obtained with a water content ≤0.5 wt%. Using the above-mentioned core-shell rubber toughening agent is beneficial to improve the fracture toughness and resistance to microcrack propagation of the cured system without significantly reducing the water resistance and barrier properties of the coating. Preferably, the median grain size D of the glass flakes is... 50 The particle size is 10–30 μm and the thickness-to-diameter ratio is 30–60. Using glass flakes with the above particle size and thickness-to-diameter ratio range is beneficial to forming a longer diffusion path of corrosive media in the epoxy main phase, thereby improving the shielding and corrosion protection capabilities. Preferably, the surface-modified nano-silica is nano-silica that has been hydrophobically modified with hexamethyldisilazane, and its average particle size is 30-60 nm; the surface-modified nano-silica can be prepared using conventional surface hydrophobication processes in the art. The above modification method helps to reduce the hydroxyl activity and hygroscopicity of nano-silica surface, improve its dispersion stability in epoxy system, and reduce the adverse effects on the storage stability of single-component latent curing system. Preferably, the reactive silane quaternary ammonium salt is octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride; by using the above-mentioned reactive silane quaternary ammonium salt, the antibacterial groups of the quaternary ammonium salt can be fixed in the silicon-containing surface functional phase through silane condensation or network embedding, so that the antibacterial function is mainly concentrated in the coating surface layer, reducing the impact of free-migrating antibacterial components on the overall film brittleness and long-term stability. Preferably, the latent imidazole curing agent is a commercially available latent imidazole adduct curing agent, and more preferably, it is an adduct latent curing agent formed by 2-methylimidazolium and isophorone diisocyanate; the average particle size of the latent imidazole curing agent is preferably 5-15 μm; the latent imidazole curing agent has good latency at room temperature and can trigger the curing of the epoxy system under heating conditions; Preferably, the dispersant is a solvent-based wetting and dispersing agent; in a specific embodiment of the present invention, ANTI-TERRA-U may be selected. Preferably, the defoamer is a solvent-based polymer defoamer. In a specific embodiment of the present invention, BYK-054 can be selected. Preferably, the leveling agent is a polyacrylate leveling agent, and in a specific embodiment of the present invention, BYK-358 can be selected; Preferably, the organic solvent is a mixture of butyl butyrate and xylene, with a mass ratio of 1:1 to 2, to balance the system's construction viscosity, phase separation rate, and subsequent curing and locking effect, thereby facilitating the formation of a distribution state with a silicon-rich surface and epoxy-rich bottom. Another aspect of the present invention is to provide a method for preparing an epoxy antibacterial and anti-corrosion coating, specifically comprising the following steps: S1: Dry the glass flakes at 100-120℃ and the surface-modified nano-silica at 80-100℃ until the moisture content of both the glass flakes and the surface-modified nano-silica is ≤0.3wt%. Cool to room temperature for later use. S2: Weigh out 50-70% of the total amount of bisphenol A type liquid epoxy resin, core-shell rubber toughening agent, dispersant, γ-glycidyl etheroxypropyltrimethoxysilane and organic solvent according to the formula, mix them, add them to the dispersion vessel, and stir and mix evenly at room temperature to obtain epoxy main phase premix. S3: Slowly add surface-modified nano-silica to the epoxy main phase premix obtained in step S2; first premix at low speed to fully wet it, then disperse at high speed. During the dispersion process, control the material temperature ≤45℃ and control the fineness at 20~40μm to obtain a dense epoxy slurry. S4: After cooling the densified epoxy slurry obtained in step S3 to room temperature, slowly add glass flakes, first stir at 300-500 rpm for 10-15 min, then stir at 500-800 rpm for 10-20 min, so that the glass flakes are evenly distributed in the epoxy main phase, and the anti-corrosion main phase slurry is obtained. S5: Weigh out the remaining 30-50% of the total amount of epoxy-terminated polysiloxane, reactive silane quaternary ammonium salt, leveling agent, defoamer, and organic solvent according to the formula, mix them, add them to another container, and stir and mix them evenly at room temperature to obtain a surface functional phase concentrate. S6: Slowly add the surface functional phase concentrate obtained in step S5 to the anti-corrosion main phase slurry obtained in step S4, first stir at 300-500 rpm for 10-15 min, then stir at 500-700 rpm for 10-15 min to obtain a uniformly mixed system. S7: After the mixture obtained in step S6 is at room temperature and there is no significant temperature rise, add the latent imidazole curing agent and stir at low speed; then degas under vacuum conditions and filter through 120-200 mesh to obtain epoxy antibacterial and anti-corrosion coating. In step S2, the core-shell rubber toughening agent is preferentially introduced into the epoxy continuous phase, which is beneficial to improving the toughness of the system and providing a stable resin matrix for the subsequent introduction of inorganic fillers; γ-glycidyl etheroxypropyltrimethoxysilane (KH560) is added to the epoxy main phase in advance, which is beneficial to enhancing the interfacial bonding between the inorganic filler and the resin, and improving the transition interface between the epoxy main phase and the silicon-containing surface functional phase. Preferably, in step S3, the specific parameters for the low-speed premixing and high-speed dispersion are: first, premix at 600-900 rpm for 10 min to fully wet the material, and then increase the speed to 1200-1800 rpm for 20-40 min to disperse the material. In step S3, the surface-modified nano-silica is preferentially dispersed in the epoxy main phase under high shear, which is beneficial to exert its interstitial densification effect; in step S4, the glass flakes are added later in a low shear manner, which is beneficial to maintain the integrity of its sheet structure and a high thickness-to-diameter ratio, thereby enhancing the shielding diffusion effect. Preferably, in step S7, the specific parameters for the low-speed stirring are: stirring at a low speed of 200-400 rpm for 10-15 minutes.

[0006] Compared with the prior art, the present invention has at least the following beneficial effects: This invention synergistically designs bisphenol A type liquid epoxy resin, epoxy-terminated polysiloxane, core-shell rubber toughening agent, glass flakes, surface-modified nano-silica, reactive silane quaternary ammonium salt, and latent imidazole curing agent. It also employs a process path of high-shear dispersion of nano-silica followed by low-shear introduction of glass flakes, subsequent compounding of surface functional phases, and final low-rate addition of the latent curing agent. This process facilitates the formation of a silica-rich surface and epoxy-rich bottom distribution in the coating during subsequent application and curing. This promotes the formation of silica-containing surface functional phases and antibacterial groups, while the bottom is dominated by a continuous epoxy phase and enriched with anti-corrosion and shielding components. This spatially rationally distributes antibacterial, weather-resistant, anti-corrosion, and toughness properties, avoiding the problems of neglecting certain functional components due to simple blending in existing epoxy antibacterial and anti-corrosion systems.

[0007] In this invention, glass flakes and surface-modified nano-silica together constitute the main anti-corrosion system. The glass flakes, with their high aspect ratio, create a tortuous diffusion path, delaying the penetration of moisture, oxygen, and corrosive media into the substrate. The surface-modified nano-silica fills the tiny gaps between the resin matrix and the flakes, improving the film's density and integrity. By first dispersing the surface-modified nano-silica under high shear and then introducing the glass flakes under low shear, sufficient deagglomeration and dispersion of the nanoparticles can be ensured while avoiding the destruction of the glass flakes' sheet-like structure due to excessive shear. This better leverages the synergistic effect of both in barrier and densification aspects, improving the system's anti-corrosion stability. Furthermore, the core-shell rubber toughening agent is pre-introduced into the epoxy continuous phase, improving the fracture toughness, impact resistance, and resistance to microcrack propagation of the cured film without significantly weakening the system's water resistance and shielding properties. Simultaneously, KH560 enhances the interfacial bonding between the inorganic components and the resin matrix and improves the stability of the transition interface between the epoxy main phase and the silicon-containing surface functional phase. This invention ensures the density of the film while maintaining mechanical integrity, thereby mitigating the defects of traditional antibacterial and anti-corrosion epoxy coatings, such as brittleness, cracking, and protective failure after long-term use.

[0008] In this invention, reactive silane quaternary ammonium salts and epoxy-terminated polysiloxanes together constitute a surface functional system. The antibacterial groups of the quaternary ammonium salts can be fixed in the silicon-containing surface functional phase through silane condensation or network embedding, so that the antibacterial effect is mainly concentrated on the coating surface. This is beneficial for inhibiting bacterial adhesion and surface reproduction, and also reduces the adverse effects of freely migrating antibacterial components on the overall film structure stability. At the same time, the introduction of epoxy-terminated polysiloxanes helps improve the weather resistance and interfacial properties of the film surface, thereby mitigating the problems of easy aging and chalking of traditional epoxy systems. Thus, this invention achieves antibacterial function without causing increased film brittleness or decreased durability due to the addition of antibacterial components. In addition, this invention uses a latent imidazole curing agent to construct a single-component latent curing system, which makes the resulting coating less prone to premature curing during preparation and storage, facilitating packaging, transportation, and application. Under subsequent temperature curing conditions, it can also effectively trigger the cross-linking curing of the epoxy system. Combining the low moisture absorption properties of surface-modified nano-silica with the control of moisture content, material temperature and addition sequence throughout the process is beneficial to improving the storage stability and finished product consistency of the coating. Attached Figure Description

[0009] Figure 1 The graph shows the antibacterial rate results of the coatings in Example 1 and Comparative Examples 1-2 against Escherichia coli and Staphylococcus aureus. Figure 2 The graph shows the results of the aging test of the coatings in Example 1 and Comparative Examples 1-2, showing the changes in gloss retention at 60°. Figure 3 The graph shows the results of the overall color difference ΔE change in the aging tests of the coatings in Example 1 and Comparative Examples 1-2. Figure 4 The graph shows the viscosity change rate results of the coatings in Example 1 and Comparative Examples 1-5 during accelerated storage testing; Figure 5 For the coating surface and Ar of Example 1 + XPS full spectrum comparison chart after sputtering. Detailed Implementation

[0010] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the raw materials involved in the present invention are all purchased through conventional commercial channels. Experimental methods without specific conditions are conventional methods and conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

[0011] Example 1: An epoxy antibacterial and anti-corrosion coating, comprising the following components by weight: 52 parts of bisphenol A type liquid epoxy resin, 10 parts of epoxy-terminated polysiloxane, 6.5 parts of core-shell rubber toughening agent, 16 parts of glass flakes, 1.6 parts of surface-modified nano silica, 1.2 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.6 parts of reactive silane quaternary ammonium salt, 4.5 parts of latent imidazole curing agent, 0.45 parts of dispersant, 0.2 parts of defoamer, 0.2 parts of leveling agent, and 8 parts of organic solvent; The core-shell rubber toughening agent has an average particle size of 200 nm. The median grain size D of the glass flakes 50 It has a thickness of 20 μm and an aspect ratio of 45; The surface-modified nano-silica has an average particle size of 40 nm and is nano-silica that has been hydrophobically modified with hexamethyldisilazane. The latent imidazole curing agent is a 2-methylimidazolium-isophorone diisocyanate adduct with an average particle size of 10 μm. The organic solvent is a mixture of butyl butyrate and xylene, with a mass ratio of 1:1. The preparation method of the epoxy antibacterial and anti-corrosion coating specifically includes the following steps: S1: Dry the glass flakes at 110℃ and the surface-modified nano-silica at 90℃ until the moisture content of both the glass flakes and the surface-modified nano-silica is ≤0.3wt%. Cool to room temperature for later use. S2: Weigh out the following components according to the formula: bisphenol A type liquid epoxy resin, core-shell rubber toughening agent, ANTI-TERRA-U, γ-glycidyl etheroxypropyltrimethoxysilane and 4.8 parts of organic solvent. Add them to the dispersion vessel and stir and mix evenly at room temperature to obtain epoxy main phase premix. S3: Slowly add surface-modified nano-silica to the epoxy main phase premix obtained in step S2; first premix at 800 rpm for 10 min to fully wet it, then increase to 1500 rpm and disperse for 30 min. During the dispersion process, control the material temperature ≤45℃ and control the fineness at 30μm to obtain a dense epoxy slurry. S4: After cooling the densified epoxy slurry obtained in step S3 to room temperature, slowly add glass flakes, stir at 400 rpm for 12 min, then stir at 600 rpm for 15 min, so that the glass flakes are evenly distributed in the epoxy main phase, and the anti-corrosion main phase slurry is obtained. S5: Weigh the epoxy-terminated polysiloxane, octadecyl dimethyl (3-trimethoxysilylpropyl) ammonium chloride, BYK-358, BYK-054 and 3.2 parts of organic solvent according to the formula, add them to another container, stir and mix evenly at room temperature to obtain a surface functional phase concentrate. S6: Slowly add the surface functional phase concentrate obtained in step S5 to the anti-corrosion main phase slurry obtained in step S4, stir at 400 rpm for 12 min first, then stir at 600 rpm for 12 min to obtain a uniformly mixed system. S7: After the mixture obtained in step S6 is at room temperature and there is no significant temperature rise, add the latent imidazole curing agent and stir at a low speed of 300 rpm for 12 min; then degas under vacuum conditions and filter through 160 mesh to obtain epoxy antibacterial and anticorrosive coating.

[0012] Example 2: An epoxy antibacterial and anti-corrosion coating, comprising the following components by weight: 55 parts of bisphenol A type liquid epoxy resin, 12 parts of epoxy-terminated polysiloxane, 8 parts of core-shell rubber toughening agent, 18 parts of glass flakes, 2 parts of surface-modified nano silica, 1.4 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.8 parts of reactive silane quaternary ammonium salt, 6 parts of latent imidazole curing agent, 0.6 parts of dispersant, 0.3 parts of defoamer, 0.3 parts of leveling agent, and 10 parts of organic solvent; The core-shell rubber toughening agent has an average particle size of 150 nm. The median grain size D of the glass flakes 50 It has a thickness of 30 μm and an aspect ratio of 60; The surface-modified nano-silica has an average particle size of 30 nm and is nano-silica that has been hydrophobically modified with hexamethyldisilazane. The latent imidazole curing agent is a 2-methylimidazolium-isophorone diisocyanate adduct with an average particle size of 5 μm. The organic solvent is a mixture of butyl butyrate and xylene, with a mass ratio of 1:1.5. The preparation method of the epoxy antibacterial and anti-corrosion coating specifically includes the following steps: S1: Dry the glass flakes at 120°C and the surface-modified nano-silica at 100°C until the moisture content of both the glass flakes and the surface-modified nano-silica is ≤0.3wt%. Cool to room temperature for later use. S2: Weigh out the bisphenol A type liquid epoxy resin, core-shell rubber toughening agent, ANTI-TERRA-U, γ-glycidyl etheroxypropyltrimethoxysilane and 7 parts of organic solvent according to the formula, add them to the dispersion vessel, stir and mix evenly at room temperature to obtain epoxy main phase premix; S3: Slowly add surface-modified nano-silica to the epoxy main phase premix obtained in step S2; first premix at 900 rpm for 10 min to fully wet it, then increase to 1800 rpm and disperse for 20 min. During the dispersion process, control the material temperature ≤45℃ and control the fineness at 20μm to obtain a dense epoxy slurry. S4: After cooling the densified epoxy slurry obtained in step S3 to room temperature, slowly add glass flakes, stir at 500 rpm for 10 min first, then stir at 800 rpm for 10 min, so that the glass flakes are evenly distributed in the epoxy main phase, and the anti-corrosion main phase slurry is obtained. S5: Weigh the epoxy-terminated polysiloxane, octadecyl dimethyl (3-trimethoxysilylpropyl)ammonium chloride, BYK-358, BYK-054 and 3 parts of organic solvent according to the formula, add them to another container, stir and mix evenly at room temperature to obtain a surface functional phase concentrate. S6: Slowly add the surface functional phase concentrate obtained in step S5 to the anti-corrosion main phase slurry obtained in step S4, stir at 500 rpm for 10 min first, then stir at 700 rpm for 10 min to obtain a uniformly mixed system. S7: After the mixture obtained in step S6 is at room temperature and there is no significant temperature rise, add the latent imidazole curing agent and stir at a low speed of 400 rpm for 10 min; then degas under vacuum conditions and filter through 200 mesh to obtain epoxy antibacterial and anti-corrosion coating.

[0013] Example 3: An epoxy antibacterial and anti-corrosion coating, comprising the following components by weight: 48 parts of bisphenol A type liquid epoxy resin, 8 parts of epoxy-terminated polysiloxane, 5 parts of core-shell rubber toughening agent, 14 parts of glass flakes, 1.2 parts of surface-modified nano silica, 0.8 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.4 parts of reactive silane quaternary ammonium salt, 3.5 parts of latent imidazole curing agent, 0.3 parts of dispersant, 0.1 parts of defoamer, 0.1 parts of leveling agent, and 6 parts of organic solvent; The core-shell rubber toughening agent has an average particle size of 300 nm. The median grain size D of the glass flakes 50 It has a thickness of 10 μm and an aspect ratio of 30; The surface-modified nano-silica has an average particle size of 60 nm and is nano-silica that has been hydrophobically modified with hexamethyldisilazane. The latent imidazole curing agent is a 2-methylimidazolium-isophorone diisocyanate adduct with an average particle size of 15 μm. The organic solvent is a mixture of butyl butyrate and xylene, with a mass ratio of 1:2. The preparation method of the epoxy antibacterial and anti-corrosion coating specifically includes the following steps: S1: Dry the glass flakes at 100℃ and the surface-modified nano-silica at 80℃ until the moisture content of both the glass flakes and the surface-modified nano-silica is ≤0.3wt%. Cool to room temperature for later use. S2: Weigh out the bisphenol A type liquid epoxy resin, core-shell rubber toughening agent, ANTI-TERRA-U, γ-glycidyl etheroxypropyltrimethoxysilane and 3 parts of organic solvent according to the formula, add them to the dispersion vessel, stir and mix evenly at room temperature to obtain epoxy main phase premix; S3: Slowly add surface-modified nano-silica to the epoxy main phase premix obtained in step S2; first premix at 600 rpm for 10 min to fully wet it, then increase to 1200 rpm and disperse for 40 min. During the dispersion process, control the material temperature ≤45℃ and control the fineness at 40μm to obtain a dense epoxy slurry. S4: After cooling the densified epoxy slurry obtained in step S3 to room temperature, slowly add glass flakes, stir at 300 rpm for 15 min, then stir at 500 rpm for 20 min, so that the glass flakes are evenly distributed in the epoxy main phase, and the anti-corrosion main phase slurry is obtained. S5: Weigh the epoxy-terminated polysiloxane, octadecyl dimethyl (3-trimethoxysilylpropyl)ammonium chloride, BYK-358, BYK-054 and 3 parts of organic solvent according to the formula, add them to another container, stir and mix evenly at room temperature to obtain a surface functional phase concentrate. S6: Slowly add the surface functional phase concentrate obtained in step S5 to the anti-corrosion main phase slurry obtained in step S4, stir at 300 rpm for 15 min first, then stir at 500 rpm for 15 min to obtain a uniformly mixed system. S7: After the mixture obtained in step S6 is at room temperature and there is no significant temperature rise, add the latent imidazole curing agent and stir at a low speed of 200 rpm for 15 min; then degas under vacuum conditions and filter through 200 mesh to obtain epoxy antibacterial and anti-corrosion coating.

[0014] Comparative Example 1: Based on Example 1, only 10 parts of epoxy-terminated polysiloxane were removed from the formulation of Example 1 and replaced with 10 parts of bisphenol A type liquid epoxy resin. The types and amounts of the remaining components and the preparation steps were the same as in Example 1. This was used to demonstrate that the role of epoxy-terminated polysiloxane in the system is not only to dilute or adjust viscosity, but also to facilitate the formation of a surface-rich silicon functional phase, improve the surface weather resistance and surface interface characteristics, and provide a carrier basis for the surface enrichment of reactive silane quaternary ammonium salts.

[0015] Comparative Example 2: Based on Example 1, only 0.6 parts of reactive silane quaternary ammonium salt were removed from the formulation of Example 1 and replaced with 0.6 parts of octadecyltrimethoxysilane. The types and amounts of the remaining components and the preparation steps were the same as in Example 1. This was used to demonstrate that the antibacterial effect of the present invention mainly comes from the antibacterial group of quaternary ammonium salt, rather than simply from the low surface energy or hydrophobicity change of the surface.

[0016] Comparative Example 3: Based on Example 1, only 6.5 parts of core-shell rubber toughening agent were removed from the formulation of Example 1 and replaced with 6.5 parts of bisphenol A type liquid epoxy resin. The types and amounts of the remaining components and the preparation steps were the same as in Example 1. This was used to demonstrate the important role of core-shell rubber toughening agent in improving film toughness, reducing brittleness, and inhibiting the formation of microcracks.

[0017] Comparative Example 4: Based on Example 1, an equal amount of unmodified nano-silica with similar particle size was used to replace the surface-modified nano-silica; this was used to demonstrate that the present invention does not emphasize the addition of nano-silica itself, but rather the nano-silica modified by hexamethyldisilazane hydrophobic modification, which plays a key role in reducing hygroscopicity, improving dispersion stability, enhancing the storage stability of single-component systems, and improving film density.

[0018] Comparative Example 5: Based on Example 1, instead of using the stepwise dispersion method of S3 and S4, surface-modified nano-silica and glass flakes were added together to the epoxy main phase and uniformly dispersed under high shear. The remaining steps and formulation remained unchanged. This was used to demonstrate that the process can simultaneously ensure the deagglomeration and dispersion of nanoparticles and the integrity of the glass flake sheet structure, thereby achieving a synergistic effect of densification and sheet shielding.

[0019] Performance testing: After the epoxy antibacterial and anti-corrosion coatings prepared in the above examples and comparative examples were allowed to stand to eliminate large air bubbles, they were applied to the test panel surface in one step using a 100μm wire bar coater. After the wet film was prepared, it was leveled at room temperature for 10 min, and then placed in a forced-air oven at 130℃ for 30 min to cure. After removal, it was placed at 25℃ and 50% relative humidity for 24 h, and then the dry film thickness was measured according to GB / T13452.2-2008. The dry film thickness of steel plate samples was uniformly controlled at 80±5μm, and the dry film thickness of glass plate samples was uniformly controlled at 60±5μm.

[0020] The impact resistance, adhesion and abrasion resistance of the coatings prepared in Examples 1-3 and Comparative Examples 1-5 were measured based on GB / T 1732-2020, GB / T 9286-2021 and GB / T 1768-2006. The test results are shown in Table 1 below.

[0021] Table 1. Results of impact resistance, adhesion, and abrasion resistance tests on coatings from Examples 1-3 and Comparative Examples 1-5

[0022] Based on the results in Table 1, in Example 1, the proportions of bisphenol A type liquid epoxy resin, epoxy-terminated polysiloxane, core-shell rubber toughening agent, glass flakes, surface-modified nano-silica, KH560, reactive silane quaternary ammonium salt, and latent imidazole curing agent are more coordinated. Furthermore, the process of first dispersing nano-silica under high shear and then introducing it under low shear with glass flakes results in a film with good density, interfacial bonding, and toughness buffering capacity, exhibiting the highest impact resistance, achieving grade 0 adhesion, and the lowest abrasion weight loss, resulting in the best overall mechanical properties.

[0023] In Comparative Example 1, the removal of epoxy-terminated polysiloxane weakened the surface silicon-containing functional phase, reducing the system's ability to regulate the surface interface and release stress, resulting in a significant decrease in impact resistance and abrasion resistance. In Comparative Example 2, although silicon-containing surface components were retained, the replacement of reactive silane quaternary ammonium salts with octadecyltrimethoxysilane reduced the synergy between the surface functional phase and the overall network. While its three properties were better than most other comparative examples, they were still significantly lower than in Example 3. In Comparative Example 3, the removal of the core-shell rubber toughening agent resulted in a lack of an effective toughening buffer phase, leading to the most significant decrease in impact resistance and abrasion resistance, as well as the worst adhesion. In Comparative Example 4, the use of unmodified nano-silica worsened dispersion stability and interstitial densification, leading to decreased film uniformity and significant deterioration in all three properties. In Comparative Example 5, the removal of the stepwise dispersion process caused glass flakes to easily break down into sheet-like structures under uniform high shear conditions, reducing the integrity of the internal structure of the film, and resulting in significantly lower impact resistance, adhesion, and abrasion resistance compared to the examples.

[0024] Corrosion resistance test: For each formulation (Examples 1-3 and Comparative Examples 4-5), three steel plate samples that had been cured and conditioned for 24 hours were taken. A single scratch, 60 mm long, was made along the length of the sample, penetrating the paint film and reaching the metal substrate. The back and edges of the sample were sealed with epoxy edge sealant, leaving only the front test area exposed. The salt spray chamber used neutral salt spray (NSS) conditions. The spray solution was prepared as a 50 g / L sodium chloride aqueous solution, and the pH was adjusted to neutral using dilute hydrochloric acid and sodium hydroxide. The chamber temperature was controlled at 35°C, and the salt spray deposition rate was controlled at 2 mL / (80 cm²). 2 •h); The sample was placed at approximately 20° to the vertical direction and tested continuously for 480 hours; After the test, the surface salt was gently rinsed with deionized water and dried at room temperature for 2 hours. Then, the blistering, rusting, and cracking of the paint film were recorded, and the single-sided corrosion spread width on both sides of the scratch was measured; Values ​​were taken at three points above, middle, and below the scratch on each test plate, and the average value was taken as the result of the test plate. Then, three parallel samples were averaged. The test results are shown in Table 2 below.

[0025] Table 2. Salt spray test results of coatings from Examples 1-3 and Comparative Examples 4-5

[0026] Based on the results in Table 2, in Example 1, the glass flakes, surface-modified nano-silica, KH560, epoxy main phase, and stepwise dispersion process showed good compatibility. The glass flakes were able to construct a relatively complete tortuous diffusion path, and the surface-modified nano-silica was able to fill the micropores and interlayer gaps of the film layer relatively fully, thereby reducing the rate of corrosive media penetration under the film and the spread along the scratches. In Comparative Example 4, after unmodified nano-silica replaced surface-modified nano-silica, the dispersion stability of nanoparticles in the epoxy main phase decreased, making it easy to form local agglomerates and micro-defects. At the same time, its hygroscopicity was relatively stronger, which was not conducive to the long-term barrier of the film layer against corrosive media. As a result, the local blistering and corrosion in the area adjacent to the scratches were more obvious after salt spray than in the example, and the width of unilateral corrosion spread was also significantly increased. In Comparative Example 5, after eliminating the stepwise dispersion process and subjecting the surface-modified nano-silica and glass flakes to a uniform high-shear treatment, although the nanoparticles could be dispersed, the glass flake structure was more easily damaged, resulting in a decreased aspect ratio. This led to a shortened shielding path and a further decrease in the integrity of the internal anti-corrosion structure of the film. Localized blistering was more pronounced after salt spray testing, corrosion was more severe in areas near scratches, and slight localized cracking occurred. The single-sided corrosion spread width was the largest, indicating that its ability to inhibit the spread of corrosion under the film was the weakest. In summary, this invention, through the synergistic effect of surface-modified nano-silica, glass flakes, and the stepwise dispersion process, enables the resulting coating to exhibit better corrosion resistance under neutral salt spray conditions, and in particular, it can effectively inhibit the further spread of corrosion under the film at scratches.

[0027] Water resistance test: For each formulation (Example 1 and Comparative Examples 4-5), take 3 steel plate samples that have been cured and conditioned for 24 hours, and conduct the test according to the immersion method in GB / T 1733-1993; seal the four sides and back of the sample with paraffin / rosin, leaving only the front coating area; add deionized water to a constant temperature glass water bath, control the water temperature at 25℃, immerse the test plate vertically in the water, so that 2 / 3 of the length of the test plate is submerged in the water, and soak continuously for 240 hours; after taking it out, use filter paper to absorb the surface moisture, let it stand for 2 hours, and then observe the surface changes such as loss of gloss, discoloration, blistering, wrinkling, and local peeling of the paint film, and measure the adhesion again. The test results are shown in Table 3.

[0028] Table 3. Appearance changes of the coatings in Examples 1 and Comparative Examples 4-5 after immersion in water for 240 hours.

[0029] Based on the results in Table 3, Example 1 maintained good structural integrity and interfacial bonding stability after immersion in water for 240 hours. This is mainly because the surface-modified nano-silica and glass flakes synergistically constructed a relatively dense barrier structure in Example 1. The modified nano-silica effectively filled the micropores in the film, while the glass flakes extended the water penetration path. Simultaneously, KH560 enhanced the interfacial bonding between the inorganic components and the epoxy main phase, and the core-shell rubber toughening agent improved the stress buffering capacity of the film after water absorption, making it less prone to localized blistering and interfacial instability after immersion. In Comparative Example 4, replacing the surface-modified nano-silica with unmodified nano-silica reduced the dispersion stability of the nanoparticles in the epoxy system, making it easier for localized agglomeration and interfacial defects to form. Furthermore, its surface hydroxyl activity was higher, and its hygroscopicity was relatively stronger, making it more prone to loss of gloss, slight whitening, and localized blistering after immersion. The adhesion also decreased from level 2 to level 3. In Comparative Example 5, due to the elimination of the stepwise dispersion process, after the surface-modified nano-silica and glass flakes underwent uniform high-shear treatment, the glass flake structure was more significantly damaged, the integrity of the internal protective structure of the film layer decreased, and water was more likely to penetrate along the defect sites and cause local interface instability. As a result, after immersion in water, it exhibited more obvious loss of gloss, blistering, slight wrinkling and slight local peeling, and the adhesion dropped from level 2 to level 4, with the worst water resistance.

[0030] Antibacterial performance test: Three glass test plates were taken from each formulation (Example 1 and Comparative Examples 1-2), coated and cured according to the aforementioned process, and then sterilized for later use; Escherichia coli and Staphylococcus aureus were selected as bacterial strains, and were inoculated into nutrient broth and cultured to the logarithmic growth phase, and then diluted with sterile PBS to 1×10⁻⁶. 5 CFU / mL; 0.4 mL of bacterial suspension was dropped onto the surface of each sample, and then covered with a sterilized polyethylene film, 40 mm × 40 mm in size, and gently pressed to spread the bacterial suspension evenly; the sample was placed in a constant temperature incubator at 35℃ and 90% relative humidity for 24 h; after incubation, 10 mL of sterile PBS neutralization and elution buffer (sterile PBS solution containing 0.1 wt% Tween 80 and 0.1 wt% lecithin) was added to each sample, and the mixture was shaken repeatedly for 1 min to allow surviving bacteria to detach into the elution buffer; the elution buffer was serially diluted 10-fold, and plates with colony counts of 30–300 CFU were selected for counting; using a control plate without antibacterial components as a baseline (blank control plate, without reactive silane quaternary ammonium salt and other antibacterial components), the antibacterial rate (%) was calculated according to the formula = (number of viable bacteria in control plate - number of viable bacteria in sample) / number of viable bacteria in control plate × 100%, and the results are as follows. Figure 1 As shown.

[0031] based on Figure 1Results analysis showed that Example 1 exhibited high antibacterial rates against both *Escherichia coli* and *Staphylococcus aureus*, indicating that its surface possesses a relatively stable and effective antibacterial function. Example 1 introduced a reactive silane quaternary ammonium salt. The quaternary ammonium salt cationic groups can be fixed in the silicon-containing surface functional phase through silane condensation or network intercalation, making them more easily enriched on the surface during subsequent film formation and curing, thus concentrating the antibacterial effect primarily on the coating surface. Simultaneously, the epoxy-terminated polysiloxane facilitates the formation of a more stable surface functional phase, providing a more suitable carrier basis for the surface distribution of the quaternary ammonium salt antibacterial groups. Example 1 demonstrated the optimal antibacterial effect. Comparative Example 1 omitted the epoxy-terminated polysiloxane and replenished it with an equal amount of bisphenol A type liquid epoxy resin. Although the system still contained reactive silane quaternary ammonium salts and retained a relatively obvious antibacterial effect, the distribution and exposure of the quaternary ammonium salt antibacterial groups on the coating surface decreased due to the lack of a silicon-containing surface functional phase as a surface enrichment carrier. As a result, its antibacterial rate against both bacteria was significantly lower than that of Example 1. This result shows that the role of epoxy-terminated polysiloxanes is not only to improve the surface interface properties, but also to enhance the function of reactive silane quaternary ammonium salts on the surface. In Comparative Example 2, after replacing the reactive silane quaternary ammonium salt with octadecyltrimethoxysilane, the system surface still has a certain degree of hydrophobicity, which may have a certain inhibitory effect on bacterial adhesion. However, due to the lack of quaternary ammonium salt cationic active centers, it cannot form an effective contact bactericidal effect. Its antibacterial rate against Escherichia coli and Staphylococcus aureus is significantly reduced, and it only shows a weak surface antibacterial ability. This result indicates that the antibacterial effect of the coating of the present invention mainly comes from the synergistic effect of the reactive silane quaternary ammonium salt and the epoxy-terminated polysiloxane surface functional phase, rather than simply from the low surface energy or hydrophobicity change.

[0032] Weather resistance test: Three steel plate samples were taken from each formulation (Example 1 and Comparative Examples 1-2), coated and cured according to a uniform process, and then placed in a xenon arc aging chamber for testing; the irradiance was 0.51 W / (m²). 2 The aging process was carried out at 63℃ (nm, 340nm), with a blackboard temperature of 63℃ and a relative humidity of 50%. The cycle program consisted of 100 min of light exposure followed by 20 min of light exposure with water spraying, for a total aging time of 500 h. Samples were taken at 0 h, 100 h, 250 h, and 500 h to measure the 60° gloss retention rate and the overall color difference ΔE. The test results are as follows: Figure 2 and Figure 3 As shown in Table 4, the adhesion was tested again after 500 hours, and the results are shown in Table 4.

[0033] Table 4. Appearance and adhesion results of the coatings of Example 1 and Comparative Examples 1-2 after 500h xenon lamp aging.

[0034] based onFigure 2 , 3 Analysis of the results in Table 4 shows that Example 1 maintained a high 60° gloss retention rate and a low overall color difference after 500 hours of xenon lamp aging, exhibiting only slight gloss loss. The adhesion changed from an initial grade of 0 to grade 1, indicating that its surface layer maintained good structural stability under the combined effects of UV irradiation, damp heat, and water spraying. This is mainly because the epoxy-terminated polysiloxane and reactive silane quaternary ammonium salt in Example 1 together constitute a relatively stable surface functional phase. The former helps improve the surface weather resistance and slow down surface degradation caused by photoaging, while the latter enhances the bonding stability between the surface functional components and the host resin through silane condensation or network embedding, thereby reducing the degree of surface chalking, gloss loss, and interfacial performance degradation during aging. In Comparative Example 1, the removal of the epoxy-terminated polysiloxane significantly weakened the surface silicon-containing functional phase. The epoxy resin surface was more directly exposed to UV and humid environments, resulting in a faster decline in gloss, a more pronounced increase in overall color difference, and significant chalking and loss of gloss after 500 hours, accompanied by localized slight cracking. Adhesion also decreased to level 3, exhibiting the worst weather resistance. These results indicate that the epoxy-terminated polysiloxane in this invention not only affects surface interface properties but also plays a crucial role in improving the surface weather resistance stability. In Comparative Example 2, the epoxy-terminated polysiloxane was still present, and its weather resistance was significantly better than Comparative Example 1. Gloss retention and overall color difference were at a moderate level. After 500 hours, only slight chalking and significant loss of gloss were observed, with no obvious cracking, and adhesion decreased to level 2. However, due to the lack of reactive silane quaternary ammonium salt, the stability and uniformity of the surface functional phase were still inferior to Example 1. Although its weather resistance was better, it was still significantly lower than Example 1. The results indicate that the improved weather resistance of this invention is due to the synergistic effect of the epoxy-terminated polysiloxane and the reactive silane quaternary ammonium salt surface functional phase, rather than the independent contribution of a single component.

[0035] Storage stability test: For each formulation (Example 1 and Comparative Examples 1-5), freshly prepared coating samples were placed into 250mL capped metal containers, 200g per container, sealed, and numbered. One container served as the initial sample, and two containers as accelerated storage samples. The accelerated storage samples were placed in a 50℃ constant temperature drying oven for 30 days, then removed and allowed to stand at 25℃ for 24 hours. Subsequently, the presence of skinning, hard sedimentation, obvious stratification, or gelation was observed. The mixture was then stirred at 300rpm for 3 minutes using a low-speed stirrer, and the ability to redisperse the mixture was recorded. The test results are shown in Table 5. The viscosity at 25℃ was then measured, and the viscosity change rate (%) relative to the initial sample was calculated as: (Viscosity after test - Initial viscosity) / Initial viscosity × 100%. The test results are shown in Table 5. Figure 4 As shown.

[0036] Table 5. Appearance and redispersibility of the coatings from Examples 1 and Comparative Examples 1-5 after 30 days of accelerated storage at 50°C.

[0037] Based on Table 5 and Figure 4 Results analysis showed that after 30 days of accelerated storage at 50℃, Example 1 exhibited no sedimentation, no obvious skinning, stratification, or gelation. It was completely redispersed and homogenized after 3 minutes of low-speed stirring at 300 rpm, exhibiting the lowest viscosity change rate. This indicates that its single-component latent curing system has good storage stability. This is attributed to the reduction in hygroscopicity and surface hydroxyl activity of the surface-modified nano-silica after hydrophobic modification with hexamethyldisilazane, thus minimizing adverse effects on the latent curing system. Epoxy-terminated polysiloxane, KH560, and reactive silane quaternary ammonium salts collectively improved the interfacial compatibility within the system. The stepwise dispersion process kept the nanoparticles and glass flakes in a relatively stable dispersed state, reducing the tendency for aggregation and sedimentation during long-term storage.

[0038] In Comparative Example 1, the removal of the epoxy-terminated polysiloxane weakened the surface functional phase in the system, reduced the interfacial coordination between resin phases and functional components, resulting in slight skinning after storage and a higher viscosity change rate than in Example 1. In Comparative Example 2, octadecyltrimethoxysilane replaced the reactive silane quaternary ammonium salt. Although it did not directly damage the single-component latent curing system, its interfacial coordination with the overall network was not as good as that of the reactive silane quaternary ammonium salt, also exhibiting slight skinning and slight stratification, with a slightly higher viscosity change rate than in Example 1. In Comparative Example 3, the removal of the core-shell rubber toughening agent reduced the number of flexible particles in the system, weakened the internal thixotropic balance and the suspension stabilizing effect on inorganic components, resulting in more pronounced sedimentation than in Example 1 and a further increase in the viscosity change rate, but overall, no serious instability was observed. In Comparative Example 4, the use of unmodified nano-silica resulted in nanoparticles with higher hygroscopicity and surface activity, but also poor dispersion stability in the epoxy main phase. This made them more prone to agglomeration, hard sedimentation, and stratification during storage, and also led to a significant increase in system viscosity, resulting in the worst storage stability. In Comparative Example 5, after eliminating the stepwise dispersion process, the surface-modified nano-silica and glass flakes underwent uniform high-shear treatment. Although this initially formed a seemingly homogeneous system, it was more prone to structural instability and significant sedimentation during storage. Redispersion also resulted in poor homogeneity, leading to significantly lower storage stability compared to Example 1.

[0039] Spectral analysis: XPS testing used monochromatic Al Kα rays as the excitation source to perform a full-spectrum scan of the sample surface, scanning the binding energy range from 0 to 1200 eV to obtain information on the elemental composition of the surface layer; subsequently, under the same testing conditions, Ar... + Ion sputtering etching was performed on the sample surface to remove the surface layer. A full-spectrum scan was then performed again to obtain the elemental composition information of the near-bulk region after surface layer removal. During the testing process, the binding energy was corrected using the C 1s peak, and the surface spectrum and Ar... +The sputtering spectra were compared and analyzed to evaluate the differences in elemental distribution between the coating surface and the near-bulk region. The results are as follows: Figure 5 As shown.

[0040] As can be seen from the spectra, the Si 2p peak at approximately 103 eV, the Cl 2p peak at approximately 200 eV, the N 1s peak at approximately 400 eV, and the O 1s peak at approximately 532 eV are all quite prominent on the surface of the coating sample of Example 1. + After sputtering, the intensities of Si 2p, Cl 2p, and N 1s peaks were significantly weakened, while the C 1s peak was relatively strengthened. This result indicates that the silicon-containing components, nitrogen-containing antibacterial components, and chlorine elements corresponding to quaternary ammonium salts were relatively enriched in the surface layer of the coating in Example 1, while the near-bulk region after surface removal was dominated by an epoxy resin phase rich in organic carbon. Specifically, the Si 2p peak in the surface sample was significantly stronger than that in the Ar⁺ sputtered sample, indicating that epoxy-terminated polysiloxane and surface-modified nano-silica tend to be distributed more in the coating surface layer, thus forming a silicon-rich surface characteristic; the Cl 2p and N 1s peaks were more prominent in the surface sample, while the Ar⁺ peak was stronger. + The significant decrease in the corresponding peaks after sputtering indicates that the chlorine- and nitrogen-containing reactive silane quaternary ammonium salts are mainly concentrated on the surface of the coating film, which is consistent with the design concept of enriching antibacterial components on the surface; at the same time, Ar + The stronger C 1s peak of the sputtered sample indicates that the proportion of continuous epoxy resin phase is higher in the near-bulk region.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An epoxy antibacterial and anti-corrosion coating, characterized in that, Its composition includes the following components by weight: 48-55 parts of bisphenol A type liquid epoxy resin, 8-12 parts of epoxy-terminated polysiloxane, 5-8 parts of core-shell rubber toughening agent, 14-18 parts of glass flakes, 1.2-2 parts of surface-modified nano silica, 0.8-1.4 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.4-0.8 parts of reactive silane quaternary ammonium salt, 3.5-6 parts of latent imidazole curing agent, 0.3-0.6 parts of dispersant, 0.1-0.3 parts of defoamer, 0.1-0.3 parts of leveling agent, and 6-10 parts of organic solvent; The dispersant is a solvent-based wetting and dispersing agent; The defoamer is a solvent-based polymer-based defoamer; The leveling agent is a polyacrylate leveling agent.

2. The epoxy antibacterial and anticorrosive coating according to claim 1, characterized in that, The core-shell rubber toughening agent is a core-shell structured elastomer particle with polybutadiene rubber as the core and polymethyl methacrylate as the shell, and its average particle size is 150-300 nm.

3. The epoxy antibacterial and anticorrosive coating according to claim 1, characterized in that, The median grain size D of the glass flakes 50 The thickness is 10–30 μm, and the aspect ratio is 30–60.

4. The epoxy antibacterial and anti-corrosion coating according to claim 1, characterized in that, The surface-modified nano-silica is nano-silica that has been hydrophobically modified with hexamethyldisilazane, and its average particle size is 30-60 nm.

5. The epoxy antibacterial and anticorrosive coating according to claim 1, characterized in that, The reactive silane quaternary ammonium salt is octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride.

6. The epoxy antibacterial and anticorrosive coating according to claim 1, characterized in that, The latent imidazole curing agent is an adduct-type latent curing agent formed by 2-methylimidazolium and isophorone diisocyanate; the average particle size of the latent imidazole curing agent is 5-15 μm.

7. The epoxy antibacterial and anticorrosive coating according to claim 1, characterized in that, The organic solvent is a mixture of butyl butyrate and xylene, with a mass ratio of 1:1 to 2.

8. A method for preparing an epoxy antibacterial and anti-corrosion coating according to any one of claims 1-7, characterized in that, Specifically, the following steps are included: S1: Dry the glass flakes and surface-modified nano-silica for later use; S2: Mix 50-70% of the total amount of bisphenol A type liquid epoxy resin, core-shell rubber toughening agent, dispersant, γ-glycidyl etheroxypropyltrimethoxysilane and organic solvent to obtain epoxy main phase premix. S3: Add surface-modified nano-silica to the epoxy main phase premix described in step S2, first premix at low speed to fully wet it, then disperse at high speed to obtain a densified epoxy slurry; S4: Add glass flakes to the densified epoxy slurry described in step S3 and mix and disperse them in a low-shear manner to obtain the anti-corrosion main phase slurry; S5: Mix epoxy-terminated polysiloxane, reactive silane quaternary ammonium salt, leveling agent, defoamer, and the remaining 30-50% of the total organic solvent to obtain a surface functional phase concentrate. S6: Add the surface functional phase concentrate described in step S5 to the anti-corrosion main phase slurry described in step S4 and mix to obtain a uniform mixed system; S7: After the uniform mixing system described in step S6 is at room temperature, add the latent imidazole curing agent, stir at low speed, and then degas and filter to obtain the epoxy antibacterial and anti-corrosion coating.

9. The method for preparing the epoxy antibacterial and anticorrosive coating according to claim 8, characterized in that, In step S3, the specific parameters for low-speed premixing and high-speed dispersion are as follows: first, premix at 600-900 rpm for 10 minutes to fully wet the mixture, and then disperse at 1200-1800 rpm for 20-40 minutes.

10. The method for preparing the epoxy antibacterial and anticorrosive coating according to claim 8, characterized in that, In step S7, the specific parameters for the low-speed stirring are: stirring at 200-400 rpm for 10-15 minutes.

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