Anticorrosive and fireproof coating for bridges and method for preparing the same

Abstract

The application discloses a kind of anticorrosive fireproof paint for bridge and preparation method thereof, anticorrosive fireproof paint includes anticorrosive layer, fireproof layer and protective layer sequentially coated from inside to outside, the anticorrosive layer is epoxy zinc-rich primer, the fireproof layer is silicone resin-based composite coating, the protective layer is fluorocarbon material, by weight percentage, the weight of anticorrosive layer is 30-40% of the total weight of the paint, the weight of fireproof layer is 40-50% of the total weight of the paint, the weight of protective layer is 15-25% of the total weight of the paint;Preparation method of anticorrosive fireproof paint includes anticorrosive layer preparation, fireproof layer preparation, protective layer preparation and coating forming;Bridge cable coated with the anticorrosive fireproof paint of the application has good fire resistance, corrosion resistance and weather resistance, can improve the performance of bridge cable and prolong the service life of bridge cable;The preparation method of the anticorrosive fireproof paint of the application is simple, suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the technical field of bridge protection materials, and in particular relates to an anti-corrosion and fireproof coating for bridges and its preparation method. Background Technology

[0002] Traditional bridge cables are primarily protected using anti-corrosion coatings combined with fire-resistant cotton and fireproof cloth. While this method meets basic corrosion protection requirements, it has significant shortcomings in fire resistance. The application of fire-resistant cotton and cloth requires secondary processing, increasing manpower, material, and time costs, potentially causing traffic congestion, and leading to issues like detachment and aging over time, affecting the protective effect. Furthermore, existing anti-corrosion coatings are mostly epoxy zinc-rich primers, which, while offering good corrosion resistance, lack fire resistance and fail to meet the protection requirements of bridge cables in high-temperature environments.

[0003] Currently, although some fire-retardant coatings exist on the market, their weather resistance, adhesion, and compatibility with anti-corrosion coatings are poor, making it impossible to form a long-term and stable protective system. Therefore, there is an urgent need to develop a bridge-specific coating that integrates anti-corrosion, fireproofing, and long-term protection to address the shortcomings of traditional protection methods, improve the safety and durability of bridge cables, and reduce maintenance costs.

[0004] Therefore, there is a need to provide a novel anti-corrosion and fireproof coating for bridges, as well as a method for preparing the coating. Summary of the Invention

[0005] One object of the present invention is to provide an anti-corrosion and fireproof coating for bridges, and another object of the present invention is to provide a method for preparing the said anti-corrosion and fireproof coating for bridges.

[0006] To achieve the first objective of this invention, the following technical solution is adopted:

[0007] A corrosion-resistant and fire-retardant coating for bridges comprises an anti-corrosion layer, a fire-retardant layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fire-retardant layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 30-40% of the total weight of the coating, the fire-retardant layer accounts for 40-50% of the total weight of the coating, and the protective layer accounts for 15-25% of the total weight of the coating.

[0008] The anti-corrosion and fireproof coating of the present invention is used on bridges. More specifically, the anti-corrosion and fireproof coating of the present invention is applied to the cables of bridges. In application, the anti-corrosion layer is first coated on the surface of the cable, then the fireproof layer is coated on the surface of the anti-corrosion layer, and finally the protective layer is coated on the surface of the fireproof layer. In the end, the bridge cable, the anti-corrosion layer, the fireproof layer and the protective layer are integrated into one, thereby enabling the bridge cable to have anti-corrosion and fireproof functions, improving its physical and chemical properties and extending its service life.

[0009] In the anti-corrosion and fireproof coating of this invention, the anti-corrosion layer, as the first line of defense in the anti-corrosion and fireproof coating system for bridge cables, is directly coated on the surface of the cable substrate, such as steel. Its main function is to prevent corrosive media from eroding the steel, while providing a good adhesion base for subsequent fireproof and protective layers. The use of an epoxy zinc-rich underlayer as the anti-corrosion layer utilizes the principle of cathodic protection in electrochemical corrosion prevention to give the anti-corrosion and fireproof coating its anti-corrosion function. Specifically, it utilizes the potential difference and passivation characteristics formed by the combination of graphene, volcanic ash, and zinc powder with the metal substrate (i.e., the bridge cable). When electrochemical corrosion occurs in the coating, the zinc powder in the coating will undergo a galvanic cell reaction with the steel substrate. The zinc at the anode loses electrons, protecting the iron at the cathode from corrosion. When chemical corrosion occurs in the coating, the passivation characteristics of the alloy powder prevent corrosion of the steel substrate. Combined with the isolating effect of volcanic ash, this achieves a good chemical protection effect, ultimately protecting the surface of the bridge cable from corrosion.

[0010] In the anti-corrosion and fireproof coating of this invention, the fireproof layer, as the core functional layer in the bridge cable anti-corrosion and fireproof coating system, is located between the anti-corrosion layer and the protective layer. Its main function is to rapidly expand and form a heat insulation barrier in the event of a fire, preventing high temperatures from being transmitted to the cable steel, thereby protecting the structural integrity of the bridge. The use of a silicone resin-based composite coating as the fireproof layer utilizes the fact that silicone resin, as a matrix, can soften and promote expansion at temperatures above 300°C, thereby preventing high temperatures from being transmitted to the cable steel.

[0011] In the anti-corrosion and protective coating of this invention, the protective layer, as the outermost protective barrier in the bridge cable anti-corrosion and fireproof coating system, is directly exposed to the natural environment. Therefore, it needs to possess functions such as weather resistance, waterproofing, antifouling, and anti-aging, thereby protecting the fireproof layer, the anti-corrosion layer, and the cable. Using fluorocarbon materials as the protective layer can enhance its mechanical properties and wear resistance.

[0012] As described above, the anti-corrosion and protective coating of the present invention includes an anti-corrosion layer, a fireproof layer, and a protective layer, which are sequentially coated from the inside out. Since the anti-corrosion layer is an epoxy zinc-rich underlayer, and the zinc powder has a relatively high density, to ensure that the anti-corrosion layer can be fully coated on the cable surface, the weight of the anti-corrosion layer must be sufficient to satisfy the condition that the anti-corrosion layer is fully coated on the cable surface. Similarly, to ensure that the fireproof layer can fully expand to form a heat insulation barrier, the fireproof layer must have sufficient heat insulation thickness, and its weight must be sufficient to satisfy the condition that the fireproof layer can fully expand and insulate the heat. Similarly, due to the low density of fluorosilicone resin, in order to ensure that the protective layer can be fully and efficiently coated on the outer surface of the fireproof layer, the weight of the protective layer must be such that it meets the condition that the protective layer can fully protect the fireproof layer, the anti-corrosion layer, and the cable steel. In this invention, through several experiments and demonstrations, it has been found that, by weight percentage, when the weight of the anti-corrosion layer is 30-40% of the total weight of the coating, the weight of the fireproof layer is 40-50% of the total weight of the coating, and the weight of the protective layer is 15-25% of the total weight of the coating, the coating has good anti-corrosion and fireproof performance.

[0013] Specifically:

[0014] Preferably, the anti-corrosion layer comprises the following components by weight percentage:

[0015] Epoxy resin: 20-22.3%; First dispersant: 0.1-0.3%; Humidifier: 0.1-0.2%; Flake zinc powder: 55-70%; Volcanic ash: 2.5-5%; Graphene: 2.5-5%; First hollow microspheres: 1-2%; First defoamer: 0.1-0.2%.

[0016] In this invention, the functions of each component of the anti-corrosion layer are as follows:

[0017] Epoxy resin: As a film-forming matrix, it provides adhesion and physical barrier for the anti-corrosion layer. Specifically, epoxy resin and cable substrate (steel) are bonded together by chemical bonds formed by the reaction of epoxy groups and metal hydroxyl groups, as well as by mechanical bonding, resulting in strong adhesion.

[0018] First dispersant: enables the stable dispersion of sheet zinc powder and graphene.

[0019] Humidifier: Improves the wettability of cable substrate, which is beneficial for the coating of anti-corrosion layer on the surface of cable substrate.

[0020] Flake zinc powder: As mentioned above, zinc powder provides cathodic protection and physical shielding for the anti-corrosion layer. Because flake zinc powder is a metal powder with a scaly structure, the scaly structure allows the flake zinc powder to spread better in the coating, forming a dense coating, thereby improving the shielding performance and corrosion resistance of the anti-corrosion layer.

[0021] Volcanic ash: enhances the mechanical structure and corrosion resistance of the anti-corrosion layer. The active SiO2 / Al2O3 in the volcanic ash reacts with epoxy resin to form siloxane bonds, which improve the hardness and chemical resistance of the anti-corrosion layer.

[0022] Graphene: When graphene is combined with the above-mentioned volcanic ash and flake zinc powder to form an anti-corrosion layer and a film, it is arranged in parallel and multi-layered layers with the surface of the bridge cable, mutually shielding each other, and finally forming a multi-layer barrier. This can effectively prevent the penetration of harmful gases or corrosive liquids from the outside into the coating, and effectively protect the metal substrate (i.e., the bridge cable) from corrosion.

[0023] The first type of hollow microspheres: its hollow structure can reduce the thermal conductivity of the anti-corrosion layer. Even in the event of a fire, it can delay the heat transfer in the early stages of the fire. Furthermore, it can reduce the overall weight of the anti-corrosion layer and prevent cracking of the anti-corrosion layer due to uneven coating thickness.

[0024] First defoamer: Eliminates air bubbles generated during the preparation of the anti-corrosion layer.

[0025] More preferably, the anti-corrosion layer comprises the following components by weight percentage:

[0026] Epoxy resin: 21%; First dispersant: 0.2%; Humidifier: 0.15%; Flake zinc powder: 69%; Volcanic ash: 4%; Graphene: 4%; First hollow microspheres: 1.5%; First defoamer: 0.15%.

[0027] Preferably, the first dispersant is a polyphosphate solution, the humectant is a modified organosiloxane copolymer, and the first defoamer is polydimethylsiloxane.

[0028] Preferably, the fire-resistant layer comprises the following components by weight percentage:

[0029] Water: 30-45%; Bentonite: 0.3-0.5%; Fiber: 0.1-0.2%; Flame retardant: 25-30%; Second hollow microspheres: 2.5-5%; Aerogel: 1-2%; Basalt composite fiber filaments: 1-2%; Composite titanium dioxide: 2-5%; Second defoamer: 0.05-0.1%; p-Toluenesulfonic acid: 1.2-1.6%; Silicone resin: 20-23%.

[0030] In this invention, the functions of each component of the fire-resistant layer are as follows:

[0031] Silicone resin: As the film-forming matrix of the fireproof layer, it provides the fireproof layer with adhesion and flexibility under high temperature conditions. Specifically, when a fire occurs, the silicone resin softens at high temperature and promotes the expansion of the fireproof layer, and works with the flame retardant to form a porous carbon layer, thereby improving the fireproof function of the fireproof layer.

[0032] Water: used as a dispersion medium for preparing fire-resistant layers.

[0033] Bentonite: As a thixotropic thickener, it can prevent sagging when the fireproof layer is applied to the surface of the preservative.

[0034] Fibers: Prevent the fireproof layer from cracking and avoid curing cracks in the fireproof layer.

[0035] Flame retardant: When a fire occurs, it can cause the fireproof layer to expand upon contact with the fire, forming a heat-insulating carbon layer, which provides fire protection for the anti-corrosion layer.

[0036] The second type of hollow microspheres has the same function as the first type of hollow microspheres. Its hollow structure can reduce the thermal conductivity of the fireproof layer. Even in the event of a fire, it can delay the heat transfer in the early stages of the fire. Furthermore, it can reduce the overall weight of the fireproof layer and prevent cracking of the fireproof layer due to uneven coating thickness.

[0037] Aerogel: Its porous structure can block heat convection and conduction, thereby improving the fire resistance of the fireproof layer.

[0038] Basalt composite fiber: Its high melting point allows the fireproof layer to maintain the integrity of the char layer skeleton in high-temperature fires. Furthermore, its high tensile strength allows the fireproof layer to suppress char layer peeling caused by strong winds or vibrations.

[0039] Composite titanium dioxide: It can enhance the reflective heat insulation and weather resistance of the fireproof layer.

[0040] Second defoamer: Eliminates air bubbles generated during the preparation of the fireproof layer.

[0041] p-Toluenesulfonic acid: Adjusts the pH of the fireproof layer, maintains the neutral environment of the flame retardant, and prevents the silicone resin from being hydrolyzed.

[0042] In this invention, the fibers in the fireproof layer serve as a reinforcing layer and can be stacked with multiple layers of silicone resin to form a composite structure. When exposed to fire, the fibers can expand rapidly to form a heat insulation layer, effectively preventing the spread of fire. This allows the bridge cable to maintain good stability and durability under conditions such as temperature changes and wind.

[0043] More preferably, the fire-resistant layer comprises the following components by weight percentage:

[0044] Water: 38.98%; Bentonite: 0.4%; Fiber: 0.15%; Flame retardant: 27%; Second hollow microspheres: 4%; Aerogel: 1.5%; Basalt composite fiber: 1.5%; Composite titanium dioxide: 3.5%; Second defoamer: 0.07%; p-Toluenesulfonic acid: 1.4%; Silicone resin: 21.5%.

[0045] Preferably, the flame retardant is a mixture of ammonium polyphosphate and expandable graphite, and the second defoamer is hydrophobic silica.

[0046] Preferably, in the flame retardant, the mass ratio of ammonium polyphosphate to expandable graphite is 3-4:1.

[0047] In flame retardants, a mixture of ammonium polyphosphate and expandable graphite can improve flame retardant efficiency and reduce thermal conductivity. When a fire occurs, ammonium polyphosphate decomposes at high temperatures to generate polyphosphoric acid, promoting the dehydration and charring of silicone resin. Simultaneously, it releases inert gases to dilute oxygen, reducing the oxygen content in the air and thus achieving a flame-retardant effect. Meanwhile, expandable graphite rapidly expands upon contact with fire to form a char layer. This char layer interweaves with the char layer formed by the ammonium polyphosphate promoting silicone resin dehydration, constructing a porous, heat-insulating structure that further blocks heat transfer. Therefore, the synergistic effect of ammonium polyphosphate and expandable graphite achieves excellent flame retardant performance. To achieve the optimal expansion-char formation balance during the flame retardant process, it is necessary to ensure that ammonium polyphosphate has sufficient acid and gas sources to form a dense char layer. At the same time, it is necessary to ensure that expandable graphite can provide rapid expansion power, but it is also necessary to avoid excessive expandable graphite, which would cause the char layer formed to be loose and affect its functionality in forming a porous and heat-insulating structure by interweaving with the char layer of ammonium polyphosphate to promote the dehydration and char formation of silicone resin. Therefore, after several experiments, it was found that the synergistic effect of ammonium polyphosphate to expandable graphite in the flame retardant is the best when the mass ratio of ammonium polyphosphate to expandable graphite in the flame retardant is 3-4:1. More preferably, the mass ratio of ammonium polyphosphate to expandable graphite is 4:1.

[0048] Preferably, the protective layer comprises the following components by weight percentage:

[0049] Fluorosilicone resin: 65-80%; Secondary dispersant: 0.3-0.5%; Wetting agent: 0.1-0.2%; Ethanol: 10-13%; Indium tin oxide: 3-5%; Propylene glycol methyl ether: 8-10%; Leveling agent: 0.1-0.2%.

[0050] In this invention, the functions of each component of the protective layer are as follows:

[0051] Fluorosilicone resin: As a film-forming matrix for the protective layer, it provides the core protective function. The fluorocarbon chains in fluorosilicone resin can give the protective layer strong weather resistance, the siloxane crosslinking network in fluorosilicone resin can enhance the density of the protective layer, and the Si-O bonds in fluorosilicone resin can provide the protective layer with strong thermal stability.

[0052] Second dispersant: Ensures that other components can be uniformly dispersed during the preparation of the protective layer.

[0053] Wetting agent: Improves the wettability of the fireproof layer, which is beneficial for the protective layer to be applied to the surface of the fireproof layer.

[0054] Ethanol: used as a dispersion medium for preparing the protective layer.

[0055] Indium tin oxide (ITO): It can absorb 280-400nm ultraviolet light, which can improve the UV protection capability of the protective layer. Furthermore, it can photocatalytically decompose organic matter on the surface of the protective layer, with a contact angle greater than 110°. In addition, it can work synergistically with fluorosilicone resin to improve the stain resistance of the protective layer.

[0056] Propylene glycol methyl ether: As a film-forming aid for the protective layer, it can slow down the volatilization rate of other components in the protective layer and improve leveling. Furthermore, it can promote the movement of molecular chain segments of fluorosilicone resin, enhance low-temperature film-forming properties, and enable the protective layer to be coated under low-temperature conditions.

[0057] Leveling agent: When the protective layer is applied to the surface of the fireproof layer, the leveling agent can eliminate wrinkles generated during the coating process and reduce surface roughness.

[0058] More preferably, the protective layer comprises the following components by weight percentage:

[0059] Fluorosilicone resin: 74.8%; Secondary dispersant: 0.4%; Wetting agent: 0.15%; Ethanol: 11.5%; Indium tin oxide: 4%; Propylene glycol methyl ether: 9%; Leveling agent: 0.15%.

[0060] Preferably, the second dispersant is a polyamine-amide salt and a polyester, the wetting agent is a fluorinated surfactant, and the leveling agent is a fluorinated polyacrylate or a polyether-modified polysiloxane.

[0061] To achieve the second objective of this invention, the following technical solution is adopted:

[0062] A method for preparing an anti-corrosion and fire-retardant coating for bridges as described above includes the following steps:

[0063] S1. Preparation of the anti-corrosion coating mixture

[0064] S11. Add epoxy resin, first dispersant and humectant to the first reaction vessel and stir and disperse for 5 min at 25-30℃ and 500-800 rpm to obtain the first mixture;

[0065] S12. Add flaky zinc powder and volcanic ash to the first mixture and stir and disperse for 25 minutes at 30-35°C and 500-800 rpm to obtain the second mixture;

[0066] S13. Add graphene, first hollow microspheres and first defoamer to the second mixture and stir and disperse for 10 minutes at 30-35℃ and 500-800rpm to obtain the anti-corrosion layer mixture.

[0067] S2, Preparation of fire-resistant layer mixture

[0068] S21. Add water and bentonite to the second reaction vessel and stir and disperse for 5 minutes at 20-25℃ and 300-500rpm to obtain the third mixture;

[0069] S22. Add fiber to the third mixture and stir and disperse it for 15 minutes at 25-30°C and 1000-1200 rpm to obtain the fourth mixture;

[0070] S23. Add flame retardant to the fourth mixture and stir and disperse for 35 minutes at 30-35°C and 1200-1500 rpm to obtain the fifth mixture;

[0071] S24. Add the second hollow microspheres, aerogel, and basalt composite fiber to the fifth mixture and stir and disperse for 8 minutes at 30-35℃ and 800-1000rpm to obtain the sixth mixture.

[0072] S25. Add composite titanium dioxide to the sixth mixture and stir and disperse it for 10 minutes at 30-35℃ and 800-1000rpm to obtain the seventh mixture;

[0073] S26. Add the second defoamer, p-toluenesulfonic acid and silicone resin to the seventh mixture and stir and disperse for 10 minutes at 30-35°C and 300-500 rpm to obtain the fireproof layer mixture.

[0074] S3, Preparation of the protective layer mixture

[0075] S31. Add fluorosilicone resin, second dispersant, wetting agent and ethanol to the third reaction vessel and stir and disperse for 5 min at 25-30℃ and 300-500 rpm to obtain the eighth mixture.

[0076] S32. Add indium tin oxide to the eighth mixture and stir and disperse for 35 minutes at 25-30°C and 800-1200 rpm to obtain the ninth mixture;

[0077] S33. Add propylene glycol methyl ether and leveling agent to the ninth mixture and stir and disperse for 5 minutes at 25-30°C and 300-500 rpm to obtain a protective layer mixture;

[0078] S4 Coating Molding

[0079] S41. Under conditions of 20MPa, use a high-pressure airless spraying device to coat the anti-corrosion layer mixture onto the cable surface, and cure it in a hot air circulating oven at 80-85℃ for 30 minutes to form an anti-corrosion layer.

[0080] S42. Coat the surface of the anti-corrosion layer with the fireproof layer mixture and cure it in an infrared drying device at 60-65℃ for 40 minutes to form a fireproof layer.

[0081] S43. The protective layer mixture is coated on the surface of the fireproof layer and cured in a high-temperature oven at 150-160°C for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating.

[0082] Preferably, the thickness of the anti-corrosion layer is 50-100 μm, the thickness of the fireproof layer is 200-300 μm, and the thickness of the protective layer is 30-50 μm.

[0083] The beneficial effects of this invention are:

[0084] Bridge cables coated with the anti-corrosion and fireproof coating of the present invention have good fire resistance, corrosion resistance and weather resistance, which can improve the performance of bridge cables and extend their service life. The preparation method of the anti-corrosion and fireproof coating of the present invention is simple and suitable for industrial production.

[0085] The anti-corrosion layer in the anti-corrosion and fireproof coating of the present invention adopts the technical solution of cathodic protection and sacrificial zinc powder anode in electrochemical anti-corrosion, which has anti-corrosion performance. Attached Figure Description

[0086] Figure 1 This is a schematic diagram showing the distribution of the anti-corrosion layer, fireproof layer, and protective layer when the anti-corrosion and fireproof coating of the present invention is applied to the surface of bridge cables. Detailed Implementation

[0087] The invention can be further understood through the specific embodiments given below, but they are not intended to limit the invention. Example 1

[0088] This embodiment 1 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 35% of the total weight of the coating, the fireproof layer accounts for 45% of the total weight of the coating, and the protective layer accounts for 20% of the total weight of the coating.

[0089] By weight percentage, the anti-corrosion coating comprises the following components:

[0090] Epoxy resin: 21%; Polyphosphate solution: 0.2%; Modified organosiloxane copolymer: 0.15%; Flake zinc powder: 69%; Volcanic ash: 4%; Graphene: 4%; First hollow microspheres: 1.5%; Polydimethylsiloxane: 0.15%.

[0091] By weight percentage, the fire-resistant layer comprises the following components:

[0092] Water: 38.98%; Bentonite: 0.4%; Fiber: 0.15%; Flame retardant: 27%; Second hollow microspheres: 4%; Aerogel: 1.5%; Basalt composite fiber filaments: 1.5%; Composite titanium dioxide: 3.5%; Hydrophobic silica: 0.07%; p-Toluenesulfonic acid: 1.4%; Silicone resin: 21.5%; Among them, the 27% flame retardant includes 21.6% ammonium polyphosphate and 5.4% expandable graphite.

[0093] By weight percentage, the protective layer comprises the following components:

[0094] Fluorosilicone resin: 74.8%; polyamine-amide salt and polyester: 0.4%; fluorinated surfactant: 0.15%; ethanol: 11.5%; indium tin oxide: 4%; propylene glycol methyl ether: 9%; polyether-modified polysiloxane: 0.15%.

[0095] The preparation method of the anti-corrosion and fireproof coating for bridges in this embodiment 1 includes the following steps:

[0096] S1. Preparation of the anti-corrosion coating mixture

[0097] S11. Add 21 parts of epoxy resin, 0.2 parts of polyphosphate ester solution and 0.15 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse for 5 min at 25°C and 500 rpm to obtain the first mixture;

[0098] S12. Add 69 parts of flake zinc powder and 4 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 30°C and 500 rpm to obtain the second mixture.

[0099] S13. Add 4 parts graphene, 1.5 parts first hollow microspheres and 0.15 parts polydimethylsiloxane to the second mixture and stir and disperse for 10 min at 30℃ and 500 rpm to obtain the anti-corrosion layer mixture.

[0100] S2, Preparation of fire-resistant layer mixture

[0101] S21. Add 38.98 parts of water and 0.4 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 20°C and 300 rpm to obtain the third mixture;

[0102] S22. Add 0.15 parts of fiber to the third mixture and stir and disperse at 25°C and 1000 rpm for 15 min to obtain the fourth mixture;

[0103] S23. Add 27 parts of flame retardant to the fourth mixture and stir and disperse at 30°C and 1200 rpm for 35 min to obtain the fifth mixture; wherein the 27 parts of flame retardant include 21.6 parts of ammonium polyphosphate and 5.4 parts of expandable graphite;

[0104] S24. Add 4 parts of the second hollow microspheres, 1.5 parts of aerogel, and 1.5 parts of basalt composite fiber to the fifth mixture and stir and disperse for 8 minutes at 30℃ and 80 rpm to obtain the sixth mixture.

[0105] S25. Add 3.5 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 30℃ and 800 rpm for 10 min to obtain the seventh mixture;

[0106] S26. Add 0.07 parts of hydrophobic silica, 1.4 parts of p-toluenesulfonic acid and 21.5 parts of silicone resin to the seventh mixture and stir and disperse at 30°C and 300 rpm for 10 min to obtain the fireproof layer mixture.

[0107] S3, Preparation of the protective layer mixture

[0108] S31. Add 74.8 parts of fluorosilicone resin, 0.4 parts of polyamine-amide salt and polyester, 0.15 parts of fluorosurfactant and 11.5 parts of ethanol to the third reaction vessel and stir and disperse at 25°C and 300 rpm for 5 min to obtain the eighth mixture.

[0109] S32. Add 4 parts of indium tin oxide to the eighth mixture and stir and disperse at 25°C and 800 rpm for 35 min to obtain the ninth mixture;

[0110] S33. Add 9 parts of propylene glycol methyl ether and 0.15 parts of polyether-modified polysiloxane to the ninth mixture and stir and disperse for 5 minutes at 25°C and 300 rpm to obtain the protective layer mixture.

[0111] S4 Coating Molding

[0112] S41. Under conditions of 20MPa, a high-pressure airless spraying device is used to coat the cable surface with a 50μm thick anti-corrosion layer mixture, and the mixture is cured in an 80℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0113] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 200μm, and cure it in an infrared drying device at 60℃ for 40min to form a fireproof layer;

[0114] S43. A protective layer mixture with a thickness of 30μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 150℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating. Example 2

[0115] This embodiment 2 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 30% of the total weight of the coating, the fireproof layer accounts for 50% of the total weight of the coating, and the protective layer accounts for 20% of the total weight of the coating.

[0116] By weight percentage, the anti-corrosion coating comprises the following components:

[0117] Epoxy resin: 22.3%; Polyphosphate solution: 0.3%; Modified organosiloxane copolymer: 0.2%; Flake zinc powder: 65%; Volcanic ash: 5%; Graphene: 5%; First hollow microspheres: 2%; Polydimethylsiloxane: 0.2%.

[0118] By weight percentage, the fire-resistant layer comprises the following components:

[0119] Water: 30.6%; Bentonite: 0.5%; Fiber: 0.2%; Flame retardant: 30%; Second hollow microspheres: 5%; Aerogel: 2%; Basalt composite fiber filaments: 2%; Composite titanium dioxide: 5%; Hydrophobic silica: 0.1%; p-Toluenesulfonic acid: 1.6%; Silicone resin: 23%; Among them, the 30% flame retardant includes 22.5% ammonium polyphosphate and 7.5% expandable graphite.

[0120] By weight percentage, the protective layer comprises the following components:

[0121] Fluorosilicone resin: 71.1%; polyamine-amide salt and polyester: 0.5%; fluorinated surfactant: 0.2%; ethanol: 13%; indium tin oxide: 5%; propylene glycol methyl ether: 10%; fluorinated modified polyacrylate: 0.2%.

[0122] The preparation method of the anti-corrosion and fireproof coating for bridges in this embodiment 2 includes the following steps:

[0123] S1. Preparation of the anti-corrosion coating mixture

[0124] S11. Add 22.3 parts of epoxy resin, 0.3 parts of polyphosphate ester solution and 0.2 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse at 30°C and 800 rpm for 5 min to obtain the first mixture;

[0125] S12. Add 65 parts of flake zinc powder and 5 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 35°C and 800 rpm to obtain the second mixture.

[0126] S13. Add 5 parts graphene, 2 parts first hollow microspheres and 0.2 parts polydimethylsiloxane to the second mixture and stir and disperse at 35°C and 800 rpm for 10 min to obtain the anti-corrosion layer mixture.

[0127] S2, Preparation of fire-resistant layer mixture

[0128] S21. Add 30.6 parts of water and 0.5 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 25°C and 500 rpm to obtain the third mixture;

[0129] S22. Add 0.2 parts of fiber to the third mixture and stir and disperse at 30°C and 1200 rpm for 15 min to obtain the fourth mixture;

[0130] S23. Add 30 parts of flame retardant to the fourth mixture and stir and disperse at 35°C and 1500 rpm for 35 min to obtain the fifth mixture; wherein the 30 parts of flame retardant include 22.5 parts of ammonium polyphosphate and 7.5 parts of expandable graphite;

[0131] S24. Add 5 parts of the second hollow microspheres, 2 parts of aerogel, and 2 parts of basalt composite fiber to the fifth mixture and stir and disperse for 8 minutes at 35°C and 1000 rpm to obtain the sixth mixture.

[0132] S25. Add 5 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 35℃ and 1000rpm for 10 minutes to obtain the seventh mixture.

[0133] S26. Add 0.1 parts of hydrophobic silica, 1.6 parts of p-toluenesulfonic acid and 23 parts of silicone resin to the seventh mixture and stir and disperse at 35°C and 500 rpm for 10 min to obtain the fireproof layer mixture.

[0134] S3, Preparation of the protective layer mixture

[0135] S31. Add 71.1 parts of fluorosilicone resin, 0.5 parts of polyamine-amide salt and polyester, 0.2 parts of fluorosurfactant and 13 parts of ethanol to the third reaction vessel and stir and disperse for 5 min at 30℃ and 500 rpm to obtain the eighth mixture;

[0136] S32. Add 5 parts of indium tin oxide to the eighth mixture and stir and disperse at 30°C and 1200 rpm for 35 min to obtain the ninth mixture;

[0137] S33. Add 10 parts of propylene glycol methyl ether and 0.2 parts of fluorinated modified polyacrylate to the ninth mixture and stir and disperse for 5 min at 30°C and 500 rpm to obtain the protective layer mixture.

[0138] S4 Coating Molding

[0139] S41. Under conditions of 20MPa, a high-pressure airless spraying device is used to coat the cable surface with an anti-corrosion layer mixture with a thickness of 100μm, and the mixture is cured in an 85℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0140] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 300μm, and cure it in an infrared drying device at 65℃ for 40min to form a fireproof layer.

[0141] S43. A protective layer mixture with a thickness of 50 μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 160℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating. Example 3

[0142] This embodiment 3 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 40% of the total weight of the coating, the fireproof layer accounts for 45% of the total weight of the coating, and the protective layer accounts for 15% of the total weight of the coating.

[0143] By weight percentage, the anti-corrosion coating comprises the following components:

[0144] Epoxy resin: 20%; Polyphosphate solution: 0.1%; Modified organosiloxane copolymer: 0.1%; Flake zinc powder: 68.7%; Volcanic ash: 5%; Graphene: 5%; First hollow microspheres: 1%; Polydimethylsiloxane: 0.1%.

[0145] By weight percentage, the fire-resistant layer comprises the following components:

[0146] Water: 42.35%; Bentonite: 0.3%; Fiber: 0.1%; Flame retardant: 27%; Second hollow microspheres: 4%; Aerogel: 1%; Basalt composite fiber filaments: 1%; Composite titanium dioxide: 2%; Hydrophobic silica: 0.05%; p-Toluenesulfonic acid: 1.2%; Silicone resin: 21%; Among them, the 27% flame retardant includes 21% ammonium polyphosphate and 6% expandable graphite.

[0147] By weight percentage, the protective layer comprises the following components:

[0148] Fluorosilicone resin: 78.5%; polyamine-amide salt and polyester: 0.3%; fluorinated surfactant: 0.1%; ethanol: 10%; indium tin oxide: 3%; propylene glycol methyl ether: 8%; polyether-modified polysiloxane: 0.1%.

[0149] The preparation method of the anti-corrosion and fireproof coating for bridges in this embodiment 3 includes the following steps:

[0150] S1. Preparation of the anti-corrosion coating mixture

[0151] S11. Add 20 parts of epoxy resin, 0.1 parts of polyphosphate ester solution and 0.1 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse for 5 min at 27°C and 600 rpm to obtain the first mixture;

[0152] S12. Add 68.7 parts of flake zinc powder and 5 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 33°C and 600 rpm to obtain the second mixture;

[0153] S13. Add 5 parts graphene, 1 part first hollow microspheres and 0.1 part polydimethylsiloxane to the second mixture and stir and disperse at 33°C and 600 rpm for 10 min to obtain the anti-corrosion layer mixture.

[0154] S2, Preparation of fire-resistant layer mixture

[0155] S21. Add 42.35 parts of water and 0.3 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 23°C and 400 rpm to obtain the third mixture;

[0156] S22. Add 0.1 part of fiber to the third mixture and stir and disperse at 27°C and 1100 rpm for 15 min to obtain the fourth mixture;

[0157] S23. Add 27 parts of flame retardant to the fourth mixture and stir and disperse at 33°C and 1300 rpm for 35 min to obtain the fifth mixture; wherein the 27 parts of flame retardant include 21 parts of ammonium polyphosphate and 6 parts of expandable graphite;

[0158] S24. Add 4 parts of the second hollow microspheres, 1 part of aerogel, and 1 part of basalt composite fiber to the fifth mixture and stir and disperse at 33℃ and 900rpm for 8min to obtain the sixth mixture.

[0159] S25. Add 2 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 33℃ and 900rpm for 10min to obtain the seventh mixture.

[0160] S26. Add 0.05 parts of hydrophobic silica, 1.2 parts of p-toluenesulfonic acid and 21 parts of silicone resin to the seventh mixture and stir and disperse at 33°C and 400 rpm for 10 min to obtain the fireproof layer mixture.

[0161] S3, Preparation of the protective layer mixture

[0162] S31. Add 78.5 parts of fluorosilicone resin, 0.3 parts of polyamine-amide salt and polyester, 0.1 parts of fluorosurfactant and 10 parts of ethanol to the third reaction vessel and stir and disperse for 5 min at 27°C and 400 rpm to obtain the eighth mixture.

[0163] S32. Add 3 parts of indium tin oxide to the eighth mixture and stir and disperse at 28°C and 1000 rpm for 35 min to obtain the ninth mixture;

[0164] S33. Add 8 parts of propylene glycol methyl ether and 0.1 parts of polyether-modified polysiloxane to the ninth mixture and stir and disperse for 5 minutes at 28°C and 400 rpm to obtain the protective layer mixture.

[0165] S4 Coating Molding

[0166] S41. Under conditions of 20MPa, a high-pressure airless spraying device is used to coat the cable surface with an anti-corrosion layer mixture with a thickness of 75μm, and the mixture is cured in an 82℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0167] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 250μm, and cure it in an infrared drying device at 65℃ for 40min to form a fireproof layer.

[0168] S43. A protective layer mixture with a thickness of 40 μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 155℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating. Example 4

[0169] This embodiment 4 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 36% of the total weight of the coating, the fireproof layer accounts for 42% of the total weight of the coating, and the protective layer accounts for 22% of the total weight of the coating.

[0170] By weight percentage, the anti-corrosion coating comprises the following components:

[0171] Epoxy resin: 21.5%; Polyphosphate ester solution: 0.2%; Modified organosiloxane copolymer: 0.2%; Flake zinc powder: 68.98%; Volcanic ash: 4.5%; Graphene: 3.5%; First hollow microspheres: 1%; Polydimethylsiloxane: 0.12%.

[0172] By weight percentage, the fire-resistant layer comprises the following components:

[0173] Water: 37.54%; Bentonite: 0.38%; Fiber: 0.2%; Flame retardant: 27.5%; Second hollow microspheres: 4.5%; Aerogel: 1.8%; Basalt composite fiber filaments: 1.5%; Composite titanium dioxide: 2.5%; Hydrophobic silica: 0.08%; p-Toluenesulfonic acid: 1.5%; Silicone resin: 22.5%; Among them, the 27.5% flame retardant includes 20.62% ammonium polyphosphate and 6.88% expandable graphite.

[0174] By weight percentage, the protective layer comprises the following components:

[0175] Fluorosilicone resin: 76.37%; polyamine-amide salt and polyester: 0.35%; fluorinated surfactant: 0.15%; ethanol: 11%; indium tin oxide: 3.5%; propylene glycol methyl ether: 8.5%; fluorinated modified polyacrylate: 0.13%.

[0176] The preparation method of the anti-corrosion and fireproof coating for bridges in Example 4 includes the following steps:

[0177] S1. Preparation of the anti-corrosion coating mixture

[0178] S11. Add 21.5 parts of epoxy resin, 0.2 parts of polyphosphate ester solution and 0.2 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse at 25°C and 700 rpm for 5 min to obtain the first mixture;

[0179] S12. Add 68.98 parts of flake zinc powder and 4.5 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 35°C and 700 rpm to obtain the second mixture;

[0180] S13. Add 3.5 parts of graphene, 1 part of the first hollow microspheres and 0.12 parts of polydimethylsiloxane to the second mixture and stir and disperse for 10 min at 35°C and 700 rpm to obtain the anti-corrosion layer mixture.

[0181] S2, Preparation of fire-resistant layer mixture

[0182] S21. Add 37.54 parts of water and 0.38 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 25°C and 350 rpm to obtain the third mixture.

[0183] S22. Add 0.2 parts of fiber to the third mixture and stir and disperse at 25°C and 1000 rpm for 15 min to obtain the fourth mixture;

[0184] S23. Add 27.5 parts of flame retardant to the fourth mixture and stir and disperse at 30°C and 1300 rpm for 35 min to obtain the fifth mixture; wherein the 27.5 parts of flame retardant includes 20.62 parts of ammonium polyphosphate and 6.88 parts of expandable graphite;

[0185] S24. Add 4.5 parts of the second hollow microspheres, 1.8 parts of aerogel, and 1.5 parts of basalt composite fiber to the fifth mixture and stir and disperse at 30℃ and 900rpm for 8min to obtain the sixth mixture.

[0186] S25. Add 2.5 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 30℃ and 850 rpm for 10 min to obtain the seventh mixture;

[0187] S26. Add 0.08 parts of hydrophobic silica, 1.5 parts of p-toluenesulfonic acid and 22.5 parts of silicone resin to the seventh mixture and stir and disperse at 30°C and 350 rpm for 10 min to obtain the fireproof layer mixture.

[0188] S3, Preparation of the protective layer mixture

[0189] S31. Add 76.37 parts of fluorosilicone resin, 0.35 parts of polyamine-amide salt and polyester, 0.15 parts of fluorosurfactant and 11 parts of ethanol to the third reaction vessel and stir and disperse at 30°C and 450 rpm for 5 min to obtain the eighth mixture.

[0190] S32. Add 3.5 parts of indium tin oxide to the eighth mixture and stir and disperse at 30°C and 1100 rpm for 35 min to obtain the ninth mixture;

[0191] S33. Add 8.5 parts of propylene glycol methyl ether and 0.13 parts of fluorinated modified polyacrylate to the ninth mixture and stir and disperse for 5 minutes at 25-30℃ and 300-500 rpm to obtain the protective layer mixture.

[0192] S4 Coating Molding

[0193] S41. Under conditions of 20MPa, a high-pressure airless spraying device is used to coat the cable surface with a 60μm thick anti-corrosion layer mixture, and the mixture is cured in an 85℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0194] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 270μm, and cure it in an infrared drying device at 60℃ for 40min to form a fireproof layer;

[0195] S43. A protective layer mixture with a thickness of 35μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 150℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating. Example 5

[0196] This embodiment 5 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 34% of the total weight of the coating, the fireproof layer accounts for 50% of the total weight of the coating, and the protective layer accounts for 16% of the total weight of the coating.

[0197] By weight percentage, the anti-corrosion coating comprises the following components:

[0198] Epoxy resin: 20.78%; Polyphosphate solution: 0.25%; Modified organosiloxane copolymer: 0.2%; Flake zinc powder: 67.07%; Volcanic ash: 5%; Graphene: 4.5%; First hollow microspheres: 2%; Polydimethylsiloxane: 0.2%.

[0199] By weight percentage, the fire-resistant layer comprises the following components:

[0200] Water: 33.55%; Bentonite: 0.5%; Fiber: 0.2%; Flame retardant: 28.5%; Second hollow microspheres: 4.8%; Aerogel: 1.5%; Basalt composite fiber filaments: 2%; Composite titanium dioxide: 4.5%; Hydrophobic silica: 0.05%; p-Toluenesulfonic acid: 1.4%; Silicone resin: 23%; Among them, the 28.5% flame retardant includes 22.8% ammonium polyphosphate and 5.7% expandable graphite.

[0201] By weight percentage, the protective layer comprises the following components:

[0202] Fluorosilicone resin: 72.1%; polyamine-amide salt and polyester: 0.5%; fluorinated surfactant: 0.2%; ethanol: 12.5%; indium tin oxide: 4.5%; propylene glycol methyl ether: 10%; polyether-modified polysiloxane: 0.2%.

[0203] The preparation method of the anti-corrosion and fireproof coating for bridges in Example 5 includes the following steps:

[0204] S1. Preparation of the anti-corrosion coating mixture

[0205] S11. Add 20.78 parts of epoxy resin, 0.25 parts of polyphosphate ester solution and 0.2 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse at 27°C and 800 rpm for 5 min to obtain the first mixture;

[0206] S12. Add 67.07 parts of flake zinc powder and 5 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 35°C and 800 rpm to obtain the second mixture;

[0207] S13. Add 4.5 parts of graphene, 2 parts of the first hollow microspheres and 0.2 parts of polydimethylsiloxane to the second mixture and stir and disperse at 33°C and 800 rpm for 10 min to obtain the anti-corrosion layer mixture.

[0208] S2, Preparation of fire-resistant layer mixture

[0209] S21. Add 33.55 parts of water and 0.5 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 25°C and 500 rpm to obtain the third mixture.

[0210] S22. Add 0.2 parts of fiber to the third mixture and stir and disperse at 30°C and 1200 rpm for 15 min to obtain the fourth mixture;

[0211] S23. Add 28.5 parts of flame retardant to the fourth mixture and stir and disperse at 30°C and 1200 rpm for 35 min to obtain the fifth mixture; wherein the 28.5 parts of flame retardant includes 22.8 parts of ammonium polyphosphate and 5.7 parts of expandable graphite;

[0212] S24. Add 4.8 parts of the second hollow microspheres, 1.5 parts of aerogel, and 2 parts of basalt composite fiber to the fifth mixture and stir and disperse for 8 minutes at 30℃ and 800 rpm to obtain the sixth mixture.

[0213] S25. Add 4.5 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 35℃ and 1000rpm for 10min to obtain the seventh mixture;

[0214] S26. Add 0.05 parts of hydrophobic silica, 1.4 parts of p-toluenesulfonic acid and 23 parts of silicone resin to the seventh mixture and stir and disperse at 35°C and 500 rpm for 10 min to obtain the fireproof layer mixture.

[0215] S3, Preparation of the protective layer mixture

[0216] S31. Add 72.1 parts of fluorosilicone resin, 0.05 parts of polyamine-amide salt and polyester, 0.2 parts of fluorosurfactant and 12.5 parts of ethanol to the third reaction vessel and stir and disperse at 30°C and 500 rpm for 5 min to obtain the eighth mixture;

[0217] S32. Add 4.5 parts of indium tin oxide to the eighth mixture and stir and disperse at 30°C and 1200 rpm for 35 min to obtain the ninth mixture;

[0218] S33. Add 10 parts of propylene glycol methyl ether and 0.2 parts of polyether-modified polysiloxane to the ninth mixture and stir and disperse for 5 minutes at 30°C and 500 rpm to obtain the protective layer mixture.

[0219] S4 Coating Molding

[0220] S41. Under conditions of 20MPa, a high-pressure airless spraying device is used to coat the cable surface with an anti-corrosion layer mixture with a thickness of 70μm, and then cured in an 85℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0221] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 300μm, and cure it in an infrared drying device at 60-65℃ for 40min to form a fireproof layer;

[0222] S43. A protective layer mixture with a thickness of 45μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 160℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating. Example 6

[0223] This embodiment 6 provides an anti-corrosion and fireproof coating for bridges, comprising an anti-corrosion layer, a fireproof layer, and a protective layer applied sequentially from the inside out. The anti-corrosion layer is an epoxy zinc-rich underlayer, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorocarbon material. By weight percentage, the anti-corrosion layer accounts for 33% of the total weight of the coating, the fireproof layer accounts for 42% of the total weight of the coating, and the protective layer accounts for 25% of the total weight of the coating.

[0224] By weight percentage, the anti-corrosion coating comprises the following components:

[0225] Epoxy resin: 21.5%; Polyphosphate solution: 0.25%; Modified organosiloxane copolymer: 0.16%; Flake zinc powder: 69.21%; Volcanic ash: 3.75%; Graphene: 3.75%; First hollow microspheres: 1.2%; Polydimethylsiloxane: 0.18%.

[0226] By weight percentage, the fire-resistant layer comprises the following components:

[0227] Water: 36.64%; Bentonite: 0.45%; Fiber: 0.16%; Flame retardant: 28%; Second hollow microspheres: 4%; Aerogel: 1.4%; Basalt composite fiber filaments: 1.6%; Composite titanium dioxide: 3.5%; Hydrophobic silica: 0.75%; p-Toluenesulfonic acid: 1.5%; Silicone resin: 22%; Among them, the 28% flame retardant includes 21% ammonium polyphosphate and 7% expandable graphite.

[0228] By weight percentage, the protective layer comprises the following components:

[0229] Fluorosilicone resin: 72.62%; polyamine-amide salt and polyester: 0.5%; fluorinated surfactant: 0.2%; ethanol: 12.8%; indium tin oxide: 4.2%; propylene glycol methyl ether: 9.5%; fluorinated modified polyacrylate: 0.18%.

[0230] The preparation method of the anti-corrosion and fireproof coating for bridges in Example 6 includes the following steps:

[0231] S1. Preparation of the anti-corrosion coating mixture

[0232] S11. Add 21.5 parts of epoxy resin, 0.25 parts of polyphosphate ester solution and 0.16 parts of modified organosiloxane copolymer to the first reaction vessel and stir and disperse at 25°C and 650 rpm for 5 min to obtain the first mixture;

[0233] S12. Add 69.21 parts of flake zinc powder and 3.75 parts of volcanic ash to the first mixture and stir and disperse for 25 minutes at 35°C and 650 rpm to obtain the second mixture;

[0234] S13. Add 3.75 parts of graphene, 1.2 parts of the first hollow microspheres and 0.18 parts of polydimethylsiloxane to the second mixture and stir and disperse at 35°C and 650 rpm for 10 min to obtain the anti-corrosion layer mixture.

[0235] S2, Preparation of fire-resistant layer mixture

[0236] S21. Add 36.64 parts of water and 0.45 parts of bentonite to the second reaction vessel and stir and disperse for 5 minutes at 25°C and 400 rpm to obtain the third mixture.

[0237] S22. Add 0.16 parts of fiber to the third mixture and stir and disperse at 30°C and 1200 rpm for 15 min to obtain the fourth mixture;

[0238] S23. Add 28 parts of flame retardant to the fourth mixture and stir and disperse at 35°C and 1300 rpm for 35 min to obtain the fifth mixture; wherein the 28 parts of flame retardant include 21 parts of ammonium polyphosphate and 7 parts of expandable graphite;

[0239] S24. Add 4 parts of the second hollow microspheres, 1.4 parts of aerogel, and 1.6 parts of basalt composite fiber to the fifth mixture and stir and disperse at 35℃ and 950rpm for 8 minutes to obtain the sixth mixture.

[0240] S25. Add 3.5 parts of composite titanium dioxide to the sixth mixture and stir and disperse at 30℃ and 950 rpm for 10 min to obtain the seventh mixture;

[0241] S26. Add 0.75 parts of hydrophobic silica, 1.5 parts of p-toluenesulfonic acid and 22 parts of silicone resin to the seventh mixture and stir and disperse for 10 min at 35°C and 450 rpm to obtain the fireproof layer mixture.

[0242] S3, Preparation of the protective layer mixture

[0243] S31. Add 72.62 parts of fluorosilicone resin, 0.5 parts of polyamine-amide salt and polyester, 0.2 parts of fluorosurfactant and 12.8 parts of ethanol to the third reaction vessel and stir and disperse at 30°C and 450 rpm for 5 min to obtain the eighth mixture;

[0244] S32. Add 4.2 parts of indium tin oxide to the eighth mixture and stir and disperse at 30°C and 1100 rpm for 35 min to obtain the ninth mixture;

[0245] S33. Add 9.5 parts of propylene glycol methyl ether and 0.18 parts of fluorinated modified polyacrylate to the ninth mixture and stir and disperse for 5 min at 30°C and 450 rpm to obtain the protective layer mixture.

[0246] S4 Coating Molding

[0247] S41. Using high pressure under 20MPa conditions

[0248] The airless spraying equipment coats the cable surface with an anti-corrosion layer mixture with a thickness of 80μm, and cures it in an 80℃ hot air circulating oven for 30 minutes to form an anti-corrosion layer.

[0249] S42. Coat the surface of the anti-corrosion layer with a fireproof layer mixture with a thickness of 240μm, and cure it in an infrared drying device at 65℃ for 40min to form a fireproof layer;

[0250] S43. A protective layer mixture with a thickness of 40 μm is coated on the surface of the fireproof layer and cured in a high-temperature oven at 155℃ for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating.

[0251] Performance testing

[0252] Test Example 1: Fire Resistance Test

[0253] The steel components of Examples 1-6 (referring to steel components with coating applied to the cable surface, hereinafter the same) were tested according to the fire resistance test standard of "GB / T9978.1". The test method was to place the steel components of each example in a standard combustion furnace and heat each steel component to 840°C within 0-30 min according to the ISO834 time-temperature curve. The load-bearing capacity, integrity, fire resistance limit and thermal insulation performance of the steel components of each example were tested. The fire resistance test results are shown in Table 1:

[0254]

[0255] As shown in Table 1, the steel components coated with the coatings of Examples 1-6 did not collapse at a high temperature of 840°C, nor did they exhibit flame penetration. Their fire resistance time exceeded 2.3 hours, even reaching 3 hours, and their back temperature did not exceed 130°C. Therefore, the steel components coated with the coatings of Examples 1-6 have strong load-bearing capacity, high integrity, long fire resistance, and good thermal insulation performance.

[0256] Test Example 2 Salt Spray Corrosion Resistance Test

[0257] The steel components from Examples 1-6 were tested according to the neutral salt spray test standard of "ASTM B117". The test method was to score the surface of the steel components in each example (scratching depth reaching the cable substrate), and then place each steel component in a 5% NaCl solution at a temperature of 35±2℃ for 720 hours. The surface condition, corrosion width, and adhesion of each steel component were observed and measured (ISO 2409). The test results of each example are shown in Tables 2-7:

[0258]

[0259]

[0260]

[0261]

[0262]

[0263]

[0264] As can be seen from the test results in Table 2-7, the cathodic protection effect of the anti-corrosion layer is significant, indicating that the technical solution of using zinc powder sacrificial anode in the anti-corrosion and fireproof coating of the present invention can improve the anti-corrosion performance of steel components coated with the coating of the present invention.

[0265] Test Example 3 Weather Resistance Test

[0266] The steel components from Examples 1-6 were subjected to weathering tests according to the test standard "GB / T 1865 (QUV accelerated aging)". The test conditions were: UV wavelength 340nm; cycle: 4h UV (60℃), 4h condensation (50℃), test period 720h. The color difference (ΔE), gloss retention rate (60°), and chalking grade (ASTM D4214) of each steel component were observed and measured. The test results of each example are shown in Tables 8-13.

[0267]

[0268]

[0269]

[0270]

[0271]

[0272]

[0273] As shown in the test results in Table 8-13, the fluorosilicone resin in the anti-corrosion and fireproof coating of the present invention enables the steel components coated with the anti-corrosion and fireproof coating of the present invention to have excellent UV resistance. In addition, the gloss retention rate of the steel components in each embodiment is not less than 90%, indicating that the anti-corrosion and fireproof coating of the present invention has good weather resistance.

[0274] In summary, the steel components coated with the anti-corrosion and fireproof coating of this invention exhibit excellent fire resistance, corrosion resistance, and good weather resistance.

[0275] The above description is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A corrosion-resistant and fire-retardant coating for bridges, characterized in that, The coating comprises, from the inside out, an anti-corrosion layer, a fireproof layer, and a protective layer. The anti-corrosion layer is an epoxy zinc-rich undercoat, the fireproof layer is a silicone resin-based composite coating, and the protective layer is a fluorosilicone material. By weight percentage, the anti-corrosion layer accounts for 30-40% of the total weight of the coating, the fireproof layer accounts for 40-50% of the total weight of the coating, and the protective layer accounts for 15-25% of the total weight of the coating. The anti-corrosion layer comprises the following components by weight percentage: Epoxy resin: 20-22.3%; First dispersant: 0.1-0.3%; Humidifier: 0.1-0.2%; Flake zinc powder: 55-70%; Volcanic ash: 2.5-5%; graphene : 2.5-5%; First hollow microspheres: 1-2%; First defoamer: 0.1-0.2%; The fire-resistant layer comprises the following components by weight percentage: Water: 30-45%; Bentonite: 0.3-0.5%; Fiber: 0.1-0.2%; Flame retardant: 25-30%; Second hollow microspheres: 2.5-5%; Aerogel: 1-2%; Basalt composite fiber: 1-2%; Composite titanium dioxide: 2-5%; Secondary defoamer: 0.05-0.1%; p-Toluenesulfonic acid: 1.2-1.6%; Silicone resin: 20-23%; The flame retardant is a mixture of ammonium polyphosphate and expandable graphite, wherein the mass ratio of ammonium polyphosphate to expandable graphite is 3-4:1; The protective layer comprises the following components by weight percentage: Fluorosilicone resin: 65-80%; Secondary dispersant: 0.3-0.5%; Wetting agent: 0.1-0.2%; Ethanol: 10-13%; Indium tin oxide: 3-5%; Propylene glycol methyl ether: 8-10%; Leveling agent: 0.1-0.2%.

2. The anti-corrosion and fireproof coating for bridges according to claim 1, characterized in that, The first dispersant is a polyphosphate ester solution, the humectant is a modified organosiloxane copolymer, and the first defoamer is polydimethylsiloxane.

3. The anti-corrosion and fireproof coating for bridges according to claim 1, characterized in that, The second defoamer is hydrophobic silica.

4. The anti-corrosion and fireproof coating for bridges according to claim 1, characterized in that, The second dispersant is a polyamine-amide salt and a polyester, the wetting agent is a fluorinated surfactant, and the leveling agent is a fluorinated modified polyacrylate or a polyether modified polysiloxane.

5. A method for preparing an anti-corrosion and fire-retardant coating for bridges as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Preparation of the anti-corrosion coating mixture S11. Add epoxy resin, first dispersant and humectant to the first reaction vessel and stir and disperse for 5 minutes at 25-30℃ and 500-800rpm to obtain the first mixture; S12. Add flaky zinc powder and volcanic ash to the first mixture and stir and disperse for 25 minutes at 30-35°C and 500-800 rpm to obtain the second mixture; S13. Add graphene, first hollow microspheres and first defoamer to the second mixture and stir and disperse for 10 minutes at 30-35℃ and 500-800rpm to obtain the anti-corrosion layer mixture. S2, Preparation of fire-resistant layer mixture S21. Add water and bentonite to the second reaction vessel and stir and disperse for 5 minutes at 20-25℃ and 300-500 rpm to obtain the third mixture; S22. Add fiber to the third mixture and stir and disperse it for 15 minutes at 25-30°C and 1000-1200 rpm to obtain the fourth mixture; S23. Add flame retardant to the fourth mixture and stir and disperse for 35 minutes at 30-35°C and 1200-1500 rpm to obtain the fifth mixture; S24. Add the second hollow microspheres, aerogel, and basalt composite fiber to the fifth mixture and stir and disperse for 8 minutes at 30-35℃ and 800-1000rpm to obtain the sixth mixture. S25. Add composite titanium dioxide to the sixth mixture and stir and disperse it for 10 minutes at 30-35℃ and 800-1000rpm to obtain the seventh mixture; S26. Add the second defoamer, p-toluenesulfonic acid and silicone resin to the seventh mixture and stir and disperse for 10 minutes at 30-35°C and 300-500 rpm to obtain the fireproof layer mixture. S3, Preparation of the protective layer mixture S31. Add fluorosilicone resin, second dispersant, wetting agent and ethanol to the third reaction vessel and stir and disperse for 5 min at 25-30℃ and 300-500 rpm to obtain the eighth mixture. S32. Add indium tin oxide to the eighth mixture and stir and disperse for 35 minutes at 25-30°C and 800-1200 rpm to obtain the ninth mixture; S33. Add propylene glycol methyl ether and leveling agent to the ninth mixture and stir and disperse for 5 minutes at 25-30°C and 300-500 rpm to obtain a protective layer mixture; S4 Coating Molding S41. Under conditions of 20MPa, use a high-pressure airless spraying device to coat the anti-corrosion layer mixture onto the cable surface, and cure it in a hot air circulating oven at 80-85℃ for 30 minutes to form an anti-corrosion layer. S42. Coat the surface of the anti-corrosion layer with the fireproof layer mixture and cure it in an infrared drying device at 60-65℃ for 40 minutes to form a fireproof layer. S43. The protective layer mixture is coated on the surface of the fireproof layer and cured in a high-temperature oven at 150-160°C for 2 hours to obtain a multi-layered anti-corrosion and fireproof coating.

6. The method for preparing an anti-corrosion and fire-retardant coating for bridges according to claim 5, characterized in that, The thickness of the anti-corrosion layer is 50-100μm, the thickness of the fireproof layer is 200-300μm, and the thickness of the protective layer is 30-50μm.

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