Durable anticorrosive coating, its preparation method and application in bridge steel structure

Abstract

This invention belongs to the field of coating technology, specifically relating to a durable anti-corrosion coating, its preparation method, and its application in bridge steel structures. In preparing the durable anti-corrosion coating, this invention first reacts magnesium nitrate hexahydrate with ZIF-67 to obtain LDH nanoparticles, and then loads them with a 2-mercaptobenzimidazole corrosion inhibitor to obtain corrosion-inhibiting LDH nanoparticles. Pyrrole and dopamine are then subjected to in-situ oxidative polymerization on the surface of the corrosion-inhibiting LDH nanoparticles to obtain a corrosion-inhibiting active filler. Next, tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, and trifluoropropylmethylcyclotrisiloxane are used as monomers to synthesize polysiloxane intermediates, and cerium chloride and allylamine are introduced to obtain an anti-UV polysiloxane curing agent. Finally, epoxy resin, the anti-UV polysiloxane curing agent, and the corrosion-inhibiting active filler are mixed and vacuum degassed to obtain the durable anti-corrosion coating. The coating prepared by this invention exhibits excellent anti-corrosion performance, durability, and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a durable anti-corrosion coating, its preparation method, and its application in bridge steel structures. Background Technology

[0002] Epoxy resin coatings are among the most widely used coatings in the field of anti-corrosion of bridge steel structures. They are characterized by strong adhesion, excellent chemical resistance, and dense film formation, effectively isolating corrosive media. However, during long-term outdoor service, epoxy resin coatings are prone to photo-oxidative aging under ultraviolet radiation, leading to powdering and cracking. Simultaneously, bridge steel structures are exposed to high-humidity, high-salt-spray marine atmospheric environments or industrial pollution environments, where corrosive media can easily penetrate to the steel substrate interface through microcracks, causing localized corrosion or even stress corrosion cracking. Furthermore, the small-molecule corrosion inhibitors commonly added to traditional epoxy anti-corrosion coatings leak out in large quantities during the early stages of coating curing, making it difficult to achieve long-term, controllable corrosion inhibition. Conventional UV absorbers have poor compatibility with epoxy resins and are prone to migration and precipitation, further weakening the protective durability of the coating.

[0003] In recent years, with the continuous expansion of the construction scale of cross-sea bridges, urban elevated roads, and steel structure bridges in my country, higher requirements have been placed on the corrosion resistance, UV aging resistance, and service life of protective coatings for bridge steel structures. While existing technologies have attempted to improve coating performance by loading corrosion inhibitors onto layered bimetallic hydroxides (LDHs) or introducing silicone-modified resins, these methods often suffer from low LDH surface corrosion inhibitor loading, mediocre corrosion resistance, and difficulties in synergistic effects between UV absorption and the curing system. Therefore, developing a durable anti-corrosion coating that combines high efficiency and high corrosion resistance with excellent UV aging resistance and responsive release of corrosion inhibitors, and applying it to the protection of bridge steel structures, has significant engineering value and practical implications. Summary of the Invention

[0004] The purpose of this invention is to provide a durable anti-corrosion coating, its preparation method, and its application in bridge steel structures, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing a durable anti-corrosion coating includes the following steps: (1) LDH nanoparticles were prepared by the cobalt dimethylimidazolium (ZIF-67) template method; LDH nanoparticles were mixed with 2-mercaptobenzimidazole solution to load 2-mercaptobenzimidazole onto LDH nanoparticles to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles were coated and modified in a polymerization system of pyrrole and dopamine to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane were reacted in the presence of potassium hydroxide to obtain a polysiloxane intermediate; the polysiloxane intermediate was reacted with cerium chloride and then reacted with allylamine in the presence of Karstedt catalyst to obtain an anti-ultraviolet polysiloxane curing agent. (3) Mix epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler evenly and degas to obtain a durable anti-corrosion coating.

[0006] As an optimization, the ZIF-67 template method in step (1) is specifically as follows: magnesium nitrate hexahydrate and ethanol are mixed at a mass ratio of 1:(95~105), stirred and dissolved at 25~30℃ to obtain a magnesium nitrate solution; ZIF-67 and magnesium nitrate solution are mixed at a mass ratio of 1:(800~900), refluxed and stirred at 85~95℃ for 1.5~2.5h, centrifuged, washed with ethanol, and dried at 75~85℃; the average particle size of ZIF-67 is 500nm~1μm, and it is purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd.

[0007] As an optimization, the loading process in step (1) is specifically as follows: 2-mercaptobenzimidazole, sodium hydroxide and deionized water are mixed at a mass ratio of 1:(0.02~0.03):(6.8~7.2), and stirred at 25~30℃ for 10~30 min to obtain a corrosion inhibitor solution; the LDH nanoparticles are dispersed in deionized water at 0.1wt% to obtain an LDH nanoparticle dispersion; the LDH nanoparticle dispersion and the corrosion inhibitor solution are mixed at a mass ratio of 1:(4.8~5.2), and stirred under reduced pressure at 25~30℃ for 2.5~3.5 h.

[0008] As an optimization, the coating modification in step (1) specifically involves: mixing the corrosion-inhibiting LDH nanoparticles, pyrrole, and tris(hydroxymethyl)aminomethane hydrochloride buffer at a mass ratio of 1:(2~2.5):(160~170), and ultrasonically treating with 100W for 20~30min to obtain a modified dispersion; adding 0.2mg / mL dopamine aqueous solution dropwise to the modified dispersion under stirring at 25~30℃, stirring for 12~18h, and then irradiating with microwaves at 850~950W for 5~10min, centrifuging, and washing with ethanol; the tris(hydroxymethyl)aminomethane hydrochloride buffer has a concentration of 10mM and a pH of 8.5, and was purchased from Shanghai Weikun Biotechnology Co., Ltd.

[0009] As an optimization, the specific preparation method of the polysiloxane intermediate in step (2) includes: mixing tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide in a mass ratio of 1:(14~16):(22~24):(0.55~0.57) and stirring under reflux at 115~125℃ for 1~1.5h.

[0010] As an optimization, the specific preparation method of the UV-resistant polysiloxane curing agent in step (2) includes: adding cerium chloride solution dropwise to the polysiloxane intermediate under stirring at 35~45℃, stirring for 3.5~4.5h after the addition is complete to obtain UV-resistant polysiloxane; mixing allylamine, Karstedt catalyst and toluene at a mass ratio of 1:(0.03~0.04):(15~25), stirring at 90~100℃ for 0.5~1h in a nitrogen atmosphere, adding 7.5~8.5 times the mass of allylamine of UV-resistant polysiloxane, stirring for 4~6h, vacuum distilling, and vacuum drying at 80℃; the Karstedt catalyst was purchased from Shanghai Beyotime Biotechnology Co., Ltd.

[0011] As an optimization, the cerium chloride solution in step (2) is prepared by dissolving cerium chloride in acetone at a concentration of 15 wt% to 25 wt%; the amount of cerium chloride used is 1 to 1.2 times the mass of tetramethyldihydrodisiloxane.

[0012] As an optimization, the reaction process of the UV-resistant polysiloxane curing agent in step (2) is as follows: .

[0013] As an optimization, the specific process of step (3) is as follows: Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler at a mass ratio of 1:(0.4~0.5):(0.004~0.006); Mix corrosion-inhibiting active filler, xylene and n-butanol at a mass ratio of 1:(20~30):(25~35), and ultrasonically treat with 100W for 10~20min to obtain corrosion inhibitor filler dispersion; Mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 25~30℃ for 10~20min, and degas under vacuum to obtain durable anti-corrosion coating; The epoxy resin is industrial grade epoxy resin E51, purchased from Nantong Xingchen Synthetic Materials Co., Ltd.

[0014] The present invention also discloses a durable anti-corrosion coating prepared by the method described above.

[0015] Application of a durable anti-corrosion coating as described above in bridge steel structures.

[0016] In preparing a durable anti-corrosion coating, this invention uses LDH nanoparticles loaded with a 2-mercaptobenzimidazole corrosion inhibitor to obtain corrosion-inhibiting LDH nanoparticles; pyrrole and dopamine are then subjected to in-situ oxidative polymerization on the surface of the corrosion-inhibiting LDH nanoparticles to obtain a corrosion-inhibiting active filler; then, tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, and trifluoropropylmethylcyclotrisiloxane are used as monomers to synthesize polysiloxane intermediates, and cerium chloride and allylamine are introduced to obtain an anti-UV polysiloxane curing agent; finally, epoxy resin, the anti-UV polysiloxane curing agent, and the corrosion-inhibiting active filler are mixed and vacuum degassed to obtain a durable anti-corrosion coating.

[0017] First, 2-mercaptobenzimidazole corrosion inhibitors were loaded onto LDH nanoparticles via vacuum impregnation. The inhibitor not only filled the hollow interior of the LDH nanoparticles but also entered the LDH interlayer through ion exchange, achieving dual loading and significantly increasing the inhibitor loading capacity. Then, a polypyrrole-polydopamine composite layer was formed on the LDH surface through the self-oxidative copolymerization of pyrrole and dopamine and microwave irradiation, resulting in a corrosion-inhibiting active filler. This composite layer physically encapsulates the internal corrosion inhibitor, effectively preventing premature leakage during coating curing and early service life. The two-dimensional layered structure of LDH in the filler also effectively extends the diffusion path of corrosive media. As a conductive polymer, polypyrrole can form a dense oxide film on the metal surface and maintain the passivation state of the metal through its reversible redox reaction, while simultaneously blocking the erosion of corrosive media such as chloride ions, thus significantly enhancing the coating's active corrosion protection and self-healing capabilities. Furthermore, the dopamine component in the filler enhances interfacial adhesion, and the conductivity of polypyrrole further synergistically improves the coating's impermeability and overall durability.

[0018] Secondly, the cerium element in the UV-resistant polysiloxane curing agent is represented by Ce. 3+ / Ce 4+The presence of cerium dioxide in its variable valence form endows the coating with excellent free radical scavenging ability, effectively inhibiting thermal and photo-oxidative degradation. Simultaneously, cerium dioxide itself is a well-known UV absorber; chemically bonding cerium to the polysiloxane chain not only achieves molecular-level dispersion but also retains its ability to absorb and shield UV rays, giving the coating significant resistance to UV aging. Furthermore, the Si-O-Si bonds in the siloxane backbone endow the coating with excellent heat resistance and hydrophobicity, while the trifluoropropyl side chains further reduce surface energy, enhancing resistance to chemical corrosion. When the above-mentioned corrosion-inhibiting active filler is blended with an anti-UV polysiloxane curing agent and epoxy resin, the polypyrrole-polydopamine layer on the filler surface contains abundant amino and catechol groups, which can participate in the ring-opening curing reaction of the epoxy resin, forming a multi-layer curing network with the amino groups in the curing agent, thereby improving the crosslinking density and interfacial adhesion of the coating. Therefore, the anti-corrosion coating prepared by the present invention has multiple functions such as active corrosion inhibition, physical barrier, anti-ultraviolet aging, anti-oxidation, chemical resistance and strong adhesion, and its overall durability is significantly better than that of the prior art. Detailed Implementation

[0019] The technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] To more clearly illustrate the method provided by the present invention, the following embodiments will be described in detail.

[0021] Example 1: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:95 and stirred at 25°C to dissolve, thus obtaining a magnesium nitrate solution; ZIF-67 and magnesium nitrate solution were mixed at a mass ratio of 1:800 and stirred under reflux at 85°C for 1.5 h, centrifuged, washed with ethanol, and dried at 75°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.02:6.8 and stirred at 25°C for 10 min to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticles. Dispersion: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:4.8 and stirred under reduced pressure at 25℃ for 2.5 h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2:160 and ultrasonicated at 100W for 20 min to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 25℃, stirred for 12 h, irradiated with microwave at 850W for 5 min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:14:22:0.55 and stirred under reflux at 115°C for 1 h to obtain a polysiloxane intermediate; cerium chloride was weighed in an amount equal to the mass of tetramethyldihydrodisiloxane and dissolved in acetone at 15 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 35°C and stirred for 3.5 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.03:15 and stirred at 90°C for 0.5 h under a nitrogen atmosphere; 7.5 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 4 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler according to a mass ratio of 1:0.4:0.004; mix corrosion-inhibiting active filler, xylene and n-butanol according to a mass ratio of 1:20:25, and ultrasonically treat with 100W for 10min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 25℃ for 10min, and degas under vacuum to obtain durable anti-corrosion coating.

[0022] Example 2: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:100 and stirred at 27°C to dissolve, thus obtaining a magnesium nitrate solution; ZIF-67 and the magnesium nitrate solution were mixed at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.025:7 and stirred at 27°C for 20 minutes to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticles. Dispersion: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:5 and stirred under reduced pressure at 27℃ for 3 h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.3:165 and ultrasonicated at 100W for 25 min to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 27℃, stirred for 14 h, irradiated with microwave at 900W for 7 min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h to obtain a polysiloxane intermediate; 1.1 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 20 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 40°C and stirred for 4 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere; 8 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 5 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler according to a mass ratio of 1:0.45:0.005; mix corrosion-inhibiting active filler, xylene and n-butanol according to a mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0023] Example 3: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate was mixed with ethanol at a mass ratio of 1:105 and stirred at 30°C to obtain a magnesium nitrate solution; ZIF-67 was mixed with the magnesium nitrate solution at a mass ratio of 1:900 and stirred under reflux at 95°C for 2.5 h, centrifuged, washed with ethanol, and dried at 85°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.03:7.2 and stirred at 30°C for 30 min to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticle solution. Dispersion preparation: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:5.2 and stirred under reduced pressure at 30℃ for 3.5h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.5:170 and ultrasonicated at 100W for 30min to obtain modified dispersion; 0.2mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 30℃, stirred for 18h, irradiated with microwave at 950W for 10min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:16:24:0.57 and stirred under reflux at 125°C for 1.5 h to obtain a polysiloxane intermediate; 1.2 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 25 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 45°C and stirred for 4.5 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.04:25 and stirred at 100°C for 1 h under a nitrogen atmosphere; 8.5 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 6 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler according to a mass ratio of 1:0.5:0.006; mix corrosion-inhibiting active filler, xylene and n-butanol according to a mass ratio of 1:30:35, and ultrasonically treat with 100W for 20 minutes to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 30℃ for 20 minutes, and degas under vacuum to obtain durable anti-corrosion coating.

[0024] Comparative Example 1: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:100 and stirred at 27°C to dissolve and obtain magnesium nitrate solution; ZIF-67 and magnesium nitrate solution were mixed at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.3:165 and sonicated at 100W for 25 minutes to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 27°C, stirred for 14 hours, irradiated with microwave at 900W for 7 minutes, centrifuged, washed with ethanol to obtain active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h to obtain a polysiloxane intermediate; 1.1 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 20 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 40°C and stirred for 4 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere; 8 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 5 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and active filler according to the mass ratio of 1:0.45:0.005; mix corrosion-inhibiting active filler, xylene and n-butanol according to the mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0025] Comparative Example 2: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate was mixed with ethanol at a mass ratio of 1:100 and stirred at 27°C to obtain a magnesium nitrate solution; ZIF-67 was mixed with the magnesium nitrate solution at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; 2-methylimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.025:7 and stirred at 27°C for 20 minutes to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticle solution. Dispersion preparation: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:5 and stirred under reduced pressure at 27℃ for 3 h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.3:165 and ultrasonicated at 100W for 25 min to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 27℃, stirred for 14 h, irradiated with microwave at 900W for 7 min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h to obtain a polysiloxane intermediate; 1.1 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 20 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 40°C and stirred for 4 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere; 8 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 5 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler according to a mass ratio of 1:0.45:0.005; mix corrosion-inhibiting active filler, xylene and n-butanol according to a mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0026] Comparative Example 3: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:100 and stirred at 27°C to dissolve, thus obtaining a magnesium nitrate solution; ZIF-67 and magnesium nitrate solution were mixed at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide and deionized water were mixed at a mass ratio of 1:0.025:7 and stirred at 27°C for 20 minutes to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain an LDH nanoparticle dispersion; the LDH nanoparticle dispersion and the corrosion inhibitor solution were mixed at a mass ratio of 1:5 and stirred under reduced pressure at 27°C for 3 hours to obtain corrosion-inhibiting LDH nanoparticles; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h to obtain a polysiloxane intermediate; 1.1 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 20 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 40°C and stirred for 4 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere; 8 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 5 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (3) Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting LDH nanoparticles according to a mass ratio of 1:0.45:0.005; mix corrosion-inhibiting LDH nanoparticles, xylene and n-butanol according to a mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion-inhibiting LDH nanoparticle dispersion; mix corrosion-inhibiting LDH nanoparticle dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0027] Comparative Example 4: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:100 and stirred at 27°C to dissolve, thus obtaining a magnesium nitrate solution; ZIF-67 and the magnesium nitrate solution were mixed at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.025:7 and stirred at 27°C for 20 minutes to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticles. Dispersion: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:5 and stirred under reduced pressure at 27℃ for 3 h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.3:165 and ultrasonicated at 100W for 25 min to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 27℃, stirred for 14 h, irradiated with microwave at 900W for 7 min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h. The mixture was then cooled to 40°C and 0.8 times the mass of tetramethyldihydrodisiloxane was added. The mixture was stirred for 4 h to obtain polysiloxane. Allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere. Allylamine was added and stirred for 5 h. The mixture was then distilled under reduced pressure and dried under vacuum at 80°C to obtain polysiloxane curing agent. (3) Weigh epoxy resin, polysiloxane curing agent, cerium oxide and corrosion inhibitor active filler in a mass ratio of 1:0.45:0.0045:0.005; mix corrosion inhibitor active filler, xylene and n-butanol in a mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, polysiloxane curing agent, cerium oxide powder and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0028] The cerium oxide used in step (3) has a purity of 99.99% and a particle size of ≤5μm, and was purchased from Shanghai Haohong Biomedical Technology Co., Ltd.

[0029] Comparative Example 5: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Magnesium nitrate hexahydrate and ethanol were mixed at a mass ratio of 1:100 and stirred at 27°C to dissolve, thus obtaining a magnesium nitrate solution; ZIF-67 and the magnesium nitrate solution were mixed at a mass ratio of 1:850 and stirred under reflux at 90°C for 2 hours, centrifuged, washed with ethanol, and dried at 80°C to obtain LDH nanoparticles; 2-mercaptobenzimidazole, sodium hydroxide, and deionized water were mixed at a mass ratio of 1:0.025:7 and stirred at 27°C for 20 minutes to obtain a corrosion inhibitor solution; LDH nanoparticles were dispersed in deionized water at 0.1 wt% to obtain LDH nanoparticles. Dispersion: LDH nanoparticle dispersion and corrosion inhibitor solution were mixed at a mass ratio of 1:5 and stirred under reduced pressure at 27℃ for 3 h to obtain corrosion-inhibiting LDH nanoparticles; corrosion-inhibiting LDH nanoparticles, pyrrole and tris(hydroxymethyl)aminomethane hydrochloride buffer were mixed at a mass ratio of 1:2.3:165 and ultrasonicated at 100W for 25 min to obtain modified dispersion; 0.2 mg / mL dopamine aqueous solution was added dropwise to modified dispersion under stirring at 27℃, stirred for 14 h, irradiated with microwave at 900W for 7 min, centrifuged, and washed with ethanol to obtain corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h. The mixture was then cooled to 40°C and 0.8 times the mass of tetramethyldihydrodisiloxane was added. The mixture was stirred for 4 h to obtain polysiloxane. Allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere. Allylamine was added and stirred for 5 h. The mixture was then distilled under reduced pressure and dried under vacuum at 80°C to obtain polysiloxane curing agent. (3) Weigh epoxy resin, polysiloxane curing agent and corrosion inhibitor active filler in a mass ratio of 1:0.45:0.005; mix corrosion inhibitor active filler, xylene and n-butanol in a mass ratio of 1:25:30, and ultrasonically treat with 100W for 15min to obtain corrosion inhibitor filler dispersion; mix corrosion inhibitor filler dispersion, polysiloxane curing agent and epoxy resin, stir at 27℃ for 15min, and degas under vacuum to obtain durable anti-corrosion coating.

[0030] Comparative Example 6: A method for preparing a durable anti-corrosion coating includes the following steps: (1) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide were mixed in a mass ratio of 1:15:23:0.56 and stirred under reflux at 120°C for 1.5 h to obtain a polysiloxane intermediate; 1.1 times the mass of tetramethyldihydrodisiloxane was weighed and dissolved in acetone at 20 wt% to obtain a cerium chloride solution; the cerium chloride solution was added dropwise to the polysiloxane intermediate under stirring at 40°C and stirred for 4 h after the addition was completed to obtain an anti-ultraviolet polysiloxane; allylamine, Karstedt catalyst and toluene were mixed in a mass ratio of 1:0.036:20 and stirred at 95°C for 1 h under a nitrogen atmosphere; 8 times the mass of allylamine was added to the anti-ultraviolet polysiloxane and stirred for 5 h; the mixture was distilled under reduced pressure and dried under vacuum at 80°C to obtain an anti-ultraviolet polysiloxane curing agent; (2) Mix epoxy resin and UV-resistant polysiloxane curing agent at a mass ratio of 1:0.45, stir at 27°C for 15 minutes, and degas under vacuum to obtain a durable anti-corrosion coating.

[0031] Experimental Example 1: Corrosion resistance, durability and mechanical properties testing Q235 carbon steel plate with dimensions of 150mm×70mm×3mm was selected. The carbon steel plate was sandblasted to Sa2.5 grade with a surface roughness of Ra=40~60μm. After sandblasting, the plate was wiped with acetone to remove dust within 4 hours to obtain a pretreated carbon steel plate. The durable anti-corrosion coating was applied to the surface of the pretreated carbon steel plate by brushing, with two coats applied and the total dry film thickness controlled to be 120~140μm. After brushing, the plate was cured for 7 days at 25~30℃ and 55~65% relative humidity to obtain a test plate for the experiment.

[0032] Corrosion resistance testing method: Electrochemical impedance spectroscopy of the test plate in 3.5wt% sodium chloride solution was tested using a three-electrode system, with a frequency range of 10 Hz. 5 ~10 -2 Hz, disturbance voltage 10mV, immersion period 30d, through impedance modulus (|Z| 0.01Hz The corrosion resistance of durable anti-corrosion coatings was analyzed. Salt spray testing was conducted according to GB / T1771 standard at 35℃ for 4000 hours, and the coating condition was observed.

[0033] Durability test method: According to GB / T14522-2008 standard, the test plates were placed in an ASR-QUV200 UV accelerated weathering tester to test their resistance to artificial weathering, with an irradiance of 1.55W / m². 2 ×nm, using an 8h light exposure + 4h condensation cycle exposure mode, the blackboard thermometer temperature during the light exposure stage is 67~73℃, the blackboard thermometer temperature during the condensation stage is 47~53℃, the relative humidity is 100%, and the aging cycle is 960h.

[0034] Mechanical property testing method: The impact resistance was determined by using a CJQ-Ⅱ paint film impactor and testing the test plate according to GB / T1732-1993. The coating was inserted upwards above the die of the impactor, and the hammer was allowed to fall freely to impact the test plate. After the test, the coating condition was observed, and the impact resistance of the coating was determined based on the height of the hammer and the peeling of the coating.

[0035] The results are shown in Table 1.

[0036] Table 1

[0037] A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-6 in Table 1 reveals that the durable anti-corrosion coating prepared by the present invention has good anti-corrosion performance, durability performance and mechanical properties.

[0038] A comparison of Examples 1-3 and Comparative Example 1 reveals that introducing 2-mercaptobenzimidazole during the preparation of the corrosion-inhibiting active filler can improve the corrosion resistance and durability of the durable anti-corrosion coating. 2-Mercaptobenzimidazole enters the interlayer and hollow interior of the LDH through reduced pressure impregnation and ion exchange. When the coating is damaged, it is released under chloride ion triggering, significantly increasing the low-frequency impedance modulus of the coating. Simultaneously, the thiol group and benzimidazole ring in the 2-mercaptobenzimidazole molecule have the ability to absorb ultraviolet light and capture free radicals, inhibiting photo-oxidative aging and thermo-oxidative aging, slowing down the degradation of epoxy resin and polysiloxane, thus maintaining high impact resistance even after artificial ultraviolet aging.

[0039] A comparison of Examples 1-3 and Comparative Example 2 reveals that replacing 2-mercaptobenzimidazole in the corrosion-inhibiting active filler with 2-methylimidazole decreases both the corrosion resistance and durability of the durable anti-corrosion coating. 2-Mercaptobenzimidazole can be deprotonated under alkaline conditions to form negatively charged sulfur anions, which can enter the LDH interlayer through ion exchange and also penetrate the hollow interior through depressurized impregnation. When the coating is damaged, chloride ions trigger its release. In contrast, 2-methylimidazole is a neutral molecule and cannot undergo ion exchange intercalation. It can only be loaded in small quantities into the hollow interior of the LDH through depressurized impregnation, resulting in a lower total loading than 2-mercaptobenzimidazole. Furthermore, its coordination ability with metal ions is weaker, leading to insufficient corrosion inhibitor release under chloride ion triggering. Meanwhile, the thiol group and benzimidazole ring in the 2-mercaptobenzimidazole molecule have excellent UV absorption and free radical scavenging capabilities, and can effectively inhibit photo-oxidative aging and thermo-oxidative aging of the coating under high loading; while 2-methylimidazole has weaker UV resistance and antioxidant capacity.

[0040] A comparison of Examples 1-3 and Comparative Example 3 reveals that coating the surface of the corrosion-inhibiting active filler with a polypyrrole copolymer dopamine layer improves both the corrosion resistance and mechanical properties of the durable anti-corrosion coating. The polypyrrole copolymer dopamine layer acts as a physical encapsulation layer, preventing premature leakage of the internal 2-mercaptobenzimidazole and ensuring that the corrosion inhibitor is released only when the coating is damaged or chloride ions are triggered, thus maintaining a long-term high impedance modulus. Furthermore, as a conductive polymer, polypyrrole can participate in the passivation process of the metal surface, promoting the formation of a dense Fe2O3 oxide film and maintaining the passivation state through its reversible redox reaction, while simultaneously blocking chloride ion corrosion. In addition, the dopamine segments contain abundant catechol and amino groups. The amino groups can participate in the ring-opening curing reaction of the epoxy resin, forming a multi-layer cross-linked network with the amino groups in the curing agent, increasing the cross-linking density and interfacial bonding of the coating, thereby significantly enhancing the impact resistance of the coating.

[0041] A comparison of Examples 1-3 and Comparative Example 4 reveals that chemically bonding cerium to the polysiloxane chain to achieve molecular-level dispersion significantly improves durability compared to directly adding cerium oxide to the coating. Cerium oxide tends to agglomerate in coatings, leading to a reduction in the effective cerium element involved in UV and oxidation resistance. Furthermore, the agglomerates themselves become stress concentration points, accelerating coating cracking and degrading mechanical properties during UV aging. However, by chemically grafting cerium onto the polysiloxane molecular chain, the cerium element is uniformly dispersed in the polymer matrix in atomic or ionic form, achieving molecular-level dispersion. Each cerium atom can independently perform UV absorption and free radical scavenging functions, resulting in a much higher UV aging resistance efficiency than physically mixed cerium oxide powder.

[0042] By comparing Examples 1-3 and Comparative Example 5, it can be found that after introducing cerium chemical bonding into the polysiloxane chain in step 2, the mechanical properties of the durable anti-corrosion coating after artificial ultraviolet aging are significantly improved.

[0043] A comparison of Examples 1-3 and Comparative Example 6 reveals that the introduction of the corrosion-inhibiting active filler significantly improves the corrosion resistance and mechanical properties of the coating. The LDH nanoparticles in the filler possess a two-dimensional layered structure, which extends the diffusion path of the corrosive medium. Simultaneously, the 2-mercaptobenzimidazole loaded between the layers can be released under chloride ion triggering and form a chelated protective film on the metal surface, significantly increasing charge transfer resistance. The surface-coated polypyrrole-polydopamine layer not only prevents premature leakage of the corrosion inhibitor, but the conductivity of polypyrrole also promotes the formation of a dense oxide film on the metal surface and maintains a passivated state, further enhancing corrosion resistance. Regarding mechanical properties, the amino and catechol groups on the dopamine chain can participate in the ring-opening curing reaction of the epoxy resin, jointly constructing a multi-linked network with the amino groups in the curing agent, increasing the crosslinking density and interfacial bonding of the coating. Simultaneously, the rigid conjugated structure of polypyrrole endows the filler with excellent stress transfer capabilities, inhibiting crack propagation, thereby significantly improving the impact toughness of the coating. Therefore, the addition of the corrosion-inhibiting active filler enables the coating to possess both excellent active corrosion protection and good mechanical properties.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended technical solutions rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the technical solutions are intended to be included within the present invention.

Claims

1. A method for preparing a durable anti-corrosion coating, characterized in that, Includes the following steps: (1) Layered double hydroxide (LDH) nanoparticles were prepared by the cobalt dimethylimidazolium (ZIF-67) template method; LDH nanoparticles were mixed with 2-mercaptobenzimidazole solution to load 2-mercaptobenzimidazole onto LDH nanoparticles to obtain corrosion-inhibiting LDH nanoparticles; the corrosion-inhibiting LDH nanoparticles were coated and modified in a pyrrole and dopamine polymerization system to obtain a corrosion-inhibiting active filler; (2) Tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane were reacted in the presence of potassium hydroxide to obtain a polysiloxane intermediate; the polysiloxane intermediate was reacted with cerium chloride and then reacted with allylamine in the presence of Karstedt catalyst to obtain an anti-ultraviolet polysiloxane curing agent. (3) Mix epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler evenly and degas to obtain a durable anti-corrosion coating.

2. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The ZIF-67 template method described in step (1) is as follows: magnesium nitrate hexahydrate and ethanol are mixed at a mass ratio of 1:(95~105), and stirred at 25~30℃ to dissolve and obtain a magnesium nitrate solution; ZIF-67 and magnesium nitrate solution are mixed at a mass ratio of 1:(800~900), refluxed and stirred at 85~95℃ for 1.5~2.5h, centrifuged, washed with ethanol, and dried at 75~85℃; the average particle size of the ZIF-67 is 500nm~1μm.

3. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The loading process described in step (1) is as follows: 2-mercaptobenzimidazole, sodium hydroxide and deionized water are mixed at a mass ratio of 1:(0.02~0.03):(6.8~7.2) and stirred at 25~30℃ for 10~30 min to obtain a corrosion inhibitor solution; the LDH nanoparticles are dispersed in deionized water at 0.1wt% to obtain an LDH nanoparticle dispersion; the LDH nanoparticle dispersion and the corrosion inhibitor solution are mixed at a mass ratio of 1:(4.8~5.2) and stirred under reduced pressure at 25~30℃ for 2.5~3.5 h.

4. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The coating modification in step (1) specifically involves: mixing the corrosion-inhibiting LDH nanoparticles, pyrrole, and tris(hydroxymethyl)aminomethane hydrochloride buffer at a mass ratio of 1:(2~2.5):(160~170), and ultrasonically treating with 100W for 20~30min to obtain a modified dispersion; adding 0.2mg / mL dopamine aqueous solution dropwise to the modified dispersion under stirring at 25~30℃, stirring for 12~18h, irradiating with microwave at 850~950W for 5~10min, centrifuging, and washing with ethanol; the concentration of the tris(hydroxymethyl)aminomethane hydrochloride is 10mM, and the pH is 8.

5.

5. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The specific preparation method of the polysiloxane intermediate in step (2) includes: mixing tetramethyldihydrodisiloxane, octamethylcyclotetrasiloxane, trifluoropropylmethylcyclotrisiloxane and potassium hydroxide in a mass ratio of 1:(14~16):(22~24):(0.55~0.57) and stirring under reflux at 115~125℃ for 1~1.5h.

6. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The specific preparation method of the UV-resistant polysiloxane curing agent in step (2) includes: adding cerium chloride solution dropwise to the polysiloxane intermediate under stirring at 35~45℃, stirring for 3.5~4.5h after the addition is complete to obtain UV-resistant polysiloxane; mixing allylamine, Karstedt catalyst and toluene at a mass ratio of 1:(0.03~0.04):(15~25), stirring at 90~100℃ for 0.5~1h in a nitrogen atmosphere, adding 7.5~8.5 times the mass of allylamine of UV-resistant polysiloxane, stirring for 4~6h, vacuum distilling, and vacuum drying at 80℃.

7. The method for preparing a durable anti-corrosion coating according to claim 6, characterized in that, The cerium chloride solution mentioned in step (2) is made by dissolving cerium chloride in acetone at a concentration of 15 wt% to 25 wt%; the amount of cerium chloride used is 1 to 1.2 times the mass of tetramethyldihydrodisiloxane.

8. The method for preparing a durable anti-corrosion coating according to claim 1, characterized in that, The specific process of step (3) is as follows: Weigh epoxy resin, UV-resistant polysiloxane curing agent and corrosion-inhibiting active filler at a mass ratio of 1:(0.4~0.5):(0.004~0.006); Mix corrosion-inhibiting active filler, xylene and n-butanol at a mass ratio of 1:(20~30):(25~35), and ultrasonically treat with 100W for 10~20min to obtain corrosion inhibitor filler dispersion; Mix corrosion inhibitor filler dispersion, UV-resistant polysiloxane curing agent and epoxy resin, stir at 25~30℃ for 10~20min, and degas under vacuum to obtain durable anti-corrosion coating; The epoxy resin is industrial grade epoxy resin E51.

9. A durable anti-corrosion coating prepared by the method for preparing a durable anti-corrosion coating as described in any one of claims 1 to 8.

10. The application of the durable anti-corrosion coating as described in claim 9 in bridge steel structures.

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