Weather-resistant heavy-duty graphene coating with long service life and preparation method thereof

Abstract

The invention discloses a long-life weather-resistant heavy-duty graphene coating and a preparation method thereof. The long-life weather-resistant heavy-duty graphene coating is composed of a component A and a component B in a mass ratio of 100: (10-15), the component A comprises the following raw materials in percentage by mass: 30%-45% of bisphenol F epoxy resin, 3%-8% of aminated graphene dispersion liquid, 15%-25% of flaky zinc powder, 10%-20% of mica iron oxide, 3%-8% of sericite powder, 0.5%-1.5% of a dispersing agent, 0.2%-0.8% of a defoaming agent, 0.3%-1.0% of a flatting agent and 10%-20% of a mixed solvent; and the component B is a polyamide curing agent. According to the invention, a synergistic protection strategy of cathode protection of a proper amount of zinc powder, physical shielding of the scale filler / graphene and chemical functional modification is adopted, so that the anticorrosive graphene coating is ensured to show excellent anticorrosive performance in severe environments such as marine atmosphere, a splash zone and a total immersion zone.

Description

Technical Field

[0001] This invention belongs to the field of marine anti-corrosion coatings, specifically relating to a long-life, weather-resistant, heavy-duty anti-corrosion graphene coating and its preparation method. Background Technology

[0002] The high salinity, high humidity, ultraviolet radiation, and microbial characteristics of the marine environment cause severe corrosion to steel structures such as marine vessels, marine platforms, port facilities, and coastal bridge steel structures that operate in the marine environment.

[0003] Traditional heavy-duty anti-corrosion coatings, such as zinc-rich primers and epoxy micaceous iron oxide intermediate coats, are widely used, but still have bottlenecks: 1) High zinc powder content, which easily generates zinc mist during welding and cutting, posing health hazards and consuming strategic resources; 2) Capillary channels are easily formed inside the coating, and medium penetration leads to a limited protective life, usually requiring major repairs every 3 to 5 years; 3) Insufficient weather resistance, after the topcoat chalks and loses its gloss, the intermediate coat and primer quickly fail; 4) High VOC content, posing a great environmental pressure.

[0004] Graphene, with its unique two-dimensional sheet structure, excellent chemical inertness, high aspect ratio, and outstanding electrical conductivity, is considered a core component of next-generation anti-corrosion materials. However, graphene is prone to agglomeration in resin matrices, exhibits poor dispersion stability, and has weak interfacial bonding with the matrix, limiting its application effectiveness. Current coatings that simply physically incorporate graphene often fail to fully realize its performance potential, resulting in limited improvement in long-term anti-corrosion effects.

[0005] Patent document CN113717610A discloses a nano-titanium modified flake zinc powder anticorrosive coating and its preparation method, comprising the following components: 30-65 parts epoxy resin, 20-50 parts flake zinc powder, 3-8 parts organobentonite, 3-12 parts γ-aminopropyltriethoxysilane, 1-5 parts nano-titanium, 5-10 parts nano-titanium dioxide, 5-15 parts fluorocarbon emulsion, 8-20 parts amine curing agent, and 10-50 parts solvent; the epoxy resin is one or more of bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, hydroxymethyl bisphenol A type epoxy resin, bromine-modified bisphenol A propane epoxy resin, and graphene-modified epoxy resin. This document effectively improves the anticorrosive properties and mechanical properties of the coating by adding nano-titanium and flake zinc powder; simultaneously, it increases the conductivity of the flake zinc powder coating, further improving the electrochemical anticorrosive effect of the paint film. However, this literature also has shortcomings such as the dispersion stability of nano-titanium powder, the consumption and lifespan limitation of flake zinc powder, and the efficiency and uniformity of electrochemical protection. It also has deficiencies in terms of process compatibility for large-scale production, coating mechanical properties, and high raw material costs. Summary of the Invention

[0006] The purpose of this invention is to provide a long-life, weather-resistant, heavy-duty anti-corrosion graphene coating and its preparation method. Through graphene functionalization modification and filler synergistic design, it achieves ultra-long life, high adhesion and low VOC, so as to overcome the defects of existing heavy-duty anti-corrosion coatings such as short life, poor environmental performance and low graphene utilization efficiency.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows.

[0008] This invention discloses a long-life, weather-resistant, heavy-duty anti-corrosion graphene coating, comprising component A and component B in a mass ratio of 100:(10-15). Component A includes the following raw materials in the indicated mass fractions: bisphenol F epoxy resin: 30%-45%, aminated graphene dispersion: 3%-8%, flake zinc powder: 15%-25%, mica iron oxide: 10%-20%, sericite powder: 3%-8%, dispersant: 0.5%-1.5%, defoamer: 0.2%-0.8%, leveling agent: 0.3%-1.0%, and mixed solvent: 10%-20%. Component B is a polyamide curing agent. The aminated graphene dispersion is a dispersion of aminated graphene in water, alcohol, or other organic solvents modified with a silane coupling agent. The mass content of the aminated graphene is 0.5%–5%, the graphene sheet diameter is 5–15 μm, the number of layers is 1–5, and the mass percentage of amino functional groups in the aminated graphene is 0.5–1.5 at%; for example, MZ-GO-NH2 from Ningbo Moxi Technology and SE1432-NH2 from Changzhou Sixth Element. The dispersion stability of the aminated graphene dispersion in component A is ≥6 months without sedimentation. The bisphenol F epoxy resin is prepared by reacting phenol and formaldehyde under acidic catalysis to produce bisphenol F, followed by polycondensation reaction with epichlorohydrin in the presence of sodium hydroxide. It has an epoxy value of 0.15–0.25 eq / 100g and a viscosity of 2000–7000 cps at 25°C. For example, the EPIKOTE epoxy resin from Hexion Corporation (USA) is a good example. TM 862 (epoxy value 0.185~0.190 eq / 100g), DER from Olin Corporation, USA. TM 354 (epoxy value 0.189~0.20 eq / 100g); after the phenolic modified epoxy resin is combined with the polyamide curing agent, the coating can achieve a surface drying time of ≤4h and a hard drying time of ≤24h at 10℃. The flaky zinc powder has an aspect ratio > 40:1, a particle size of 200-800 mesh, and a purity ≥ 99.9%; for example, Eckart's ZNY-201 from Germany has an aspect ratio > 50. The mica iron oxide has a flake-like structure with a particle size distribution of 10-50 μm, such as Shanghai Huijingya's HJ-Y-2, which has a flake diameter of 30 μm; the flake-like zinc powder and mica iron oxide can form a synergistic network of physical isolation and cathodic protection with aminated graphene in the coating. The sericite powder is fine-grained, flaky muscovite with a diameter-to-thickness ratio >80 and a particle size of 200-2000 mesh, such as Chuzhou Gree's GR-80. The dispersant is a high molecular block copolymer containing anchoring groups, such as BYK-2150 from BYK Germany; the defoamer is an organosilicone defoamer, such as BYK-141; and the leveling agent is an organosilicone surfactant, such as BYK-331. The mixed solvent is a compound of propylene glycol methyl ether acetate (PMA) and No. 150 solvent oil in a mass ratio of 1:1 to 1:2; The polyamide curing agent is a modified polyamide curing agent with an amine value of 280-350 mg KOH / g and a viscosity of 2000-3500 mPa·s at 25°C; for example, Evonik Ancamide 2353.

[0009] The preparation method of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating of the present invention includes the following preparation steps for component A: (1) Add the phenolic modified epoxy resin to the mixed solvent of the specified amount, and then add the dispersant, defoamer and leveling agent, and stir to mix evenly; (2) Add the flake-shaped zinc powder, mica iron oxide and sericite powder in sequence, and stir to mix evenly; (3) Add the amino-based graphene dispersion and stir until the graphene is uniformly dispersed without agglomeration; (4) Adjust the viscosity to 60-90s with the remaining mixed solvent to the 4-cup of the Forte 4 cup, filter, and obtain component A.

[0010] Preferably, step (1) involves stirring at a speed of 400-600 r / min for 10-15 min to mix the raw materials evenly; step (2) involves stirring at a speed of 800-1200 r / min for 20-30 min to mix the raw materials evenly; and step (3) involves stirring at a speed of 600-800 r / min for 30-45 min.

[0011] Preferably, in step (3), a disc-type dispersion disc is used for stirring and dispersion, the linear velocity of the dispersion disc is 10-15 m / s, and the system temperature is controlled below 40℃ during the dispersion process.

[0012] The present invention also provides the application of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating in the protection of steel structures of ships, offshore platforms, port facilities and coastal bridges.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention uses modified epoxy resin as the film-forming material and introduces aminated graphene as the core anti-corrosion filler. The amino functional groups on the surface of aminated graphene can chemically bond with epoxy resin to enhance interfacial bonding and effectively prevent the stacking of flakes, achieving stable dispersion. By combining aminated graphene with flake zinc powder (cathode protection) and mica iron oxide (physical shielding) in terms of morphology and function, a dense triple synergistic network shielding layer of "physical shielding-electrochemical protection-inert barrier" is constructed, while retaining electrochemical protection capabilities, thereby achieving triple synergistic protection.

[0014] The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating of this invention exhibits excellent anti-corrosion performance in harsh environments such as marine atmospheres, splash zones, and full immersion zones. Its salt spray resistance time is ≥6000h, adhesion (cross-cut test) is grade 0, artificial weathering resistance is ≥4000h, volume solids content is ≥80%, and VOC content is <150g / L. It solves the shortcomings of traditional heavy-duty anti-corrosion coatings in terms of long-term protection, adhesion maintenance, and environmental friendliness. Detailed Implementation

[0015] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0016] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0017] Example 1 A long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is composed of two components, A and B, in a mass ratio of 100:12. Component A includes the following raw materials by mass fraction: Bisphenol F epoxy resin (EPIKOTE of Hexion, USA) TM 862) 38%; Aminographene dispersion (MZ-GO-NH2 from Ningbo Moxi Technology, graphene solid content 5%) 6% (equivalent to 0.3% dry graphene); Flake zinc powder (ZNY-201 from Eckart, Germany, aspect ratio >50) 20%; Mica iron oxide (HJ-Y-2 from Shanghai Huijingya, flake diameter 30μm) 15%; Sericite powder (GR-80 from Chuzhou Gree) 5%; Dispersant (BYK-2150) 1%; Defoamer (BYK-141) 0.5%; Leveling agent (BYK-331) 0.5%; Mixed solvent (PMA / 150 solvent oil = 1:1) 14%; Component B is a polyamide curing agent (Evonik Ancamide 2353).

[0018] The preparation method of long-life, weather-resistant, heavy-duty anti-corrosion graphene coating includes the following preparation steps for component A: (1) Pre-dispersion: Add bisphenol F epoxy resin, half of the mixed solvent, dispersant, defoamer and leveling agent to the dispersion vessel, and stir at 500 r / min for 12 min to make them evenly mixed; (2) Grinding and dispersing: Under stirring, slowly add flake zinc powder, mica iron oxide and sericite powder in sequence, increase the speed to 1000 r / min, and disperse for 25 min to make them evenly mixed; (3) Introduction of graphene: Slowly add the aminated graphene dispersion, switch to a disc dispersion disc, control the linear velocity to 12 m / s, the rotation speed to 700 r / min, disperse for 35 min, and keep the temperature below 35℃ to ensure that the graphene is uniformly dispersed without agglomeration. (4) Paint mixing: Adjust the viscosity to 75 seconds with the remaining mixed solvent, filter through a 100-mesh filter to obtain component A.

[0019] Example 2 A long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is composed of two components, A and B, in a mass ratio of 100:13. Component A includes the following raw materials by mass fraction: Bisphenol F epoxy resin (EPIKOTE of Hexion, USA) TM 862) 35%, Aminographene Dispersion (Changzhou Sixth Element SE1432-NH2) 5%, Flake Zinc Powder (Germany Eckart ZNY-201, aspect ratio >50) 18%, Mica Iron Oxide (Shanghai Huijingya HJ-Y-2, flake diameter 30μm) 18%, Sericite Powder (Chuzhou Gree GR-80) 6%, Dispersant (BYK-2150) 1.2%, Defoamer (BYK-141) 0.6%, Leveling Agent (BYK-331) 0.7%, Mixed Solvent (PMA / 150 Solvent Oil = 1:1.5) 15.5%; Component B is a polyamide curing agent (Evonik Ancamide 2353).

[0020] The preparation method of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is the same as in Example 1.

[0021] Example 3 A long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is composed of two components, A and B, in a mass ratio of 100:15. Component A includes the following raw materials by mass fraction: Bisphenol F epoxy resin (DER from Olin Corporation, USA). TM354) 45%, Aminographene Dispersion (Changzhou Sixth Element SE1432-NH2, graphene solid content 4%) 5%, Flake Zinc Powder (Germany Eckart ZNY-201, aspect ratio >50) 15%, Mica Iron Oxide (Shanghai Huijingya HJ-Y-2, flake diameter 30μm) 12%, Sericite Powder (Chuzhou Gree GR-80) 4%, Dispersant (BYK-2150) 1.0%, Defoamer (BYK-141) 0.5%, Leveling Agent (BYK-331) 0.5%, Mixed Solvent (PMA / 150 Solvent Oil = 1:1.5) 17%; Component B is a polyamide curing agent (Evonik Ancamide 2353).

[0022] The preparation method of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is the same as in Example 1.

[0023] Example 4 A long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is composed of two components, A and B, in a mass ratio of 100:10. Component A includes the following raw materials by mass fraction: Bisphenol F epoxy resin (DER from Olin Corporation, USA). TM 354) 30%, Aminographene Dispersion (Changzhou Sixth Element SE1432-NH2, graphene solid content 4%) 8%, Flake Zinc Powder (Germany Eckart ZNY-201, aspect ratio >50) 21.3%, Mica Iron Oxide (Shanghai Huijingya HJ-Y-2, flake diameter 30μm) 20%, Sericite Powder (Chuzhou Gree GR-80) 8%, Dispersant (BYK-2150) 1.5%, Defoamer (BYK-141) 0.5%, Leveling Agent (BYK-331) 0.7%, Mixed Solvent (PMA / 150 Solvent Oil = 1:1.5) 10%; Component B is a polyamide curing agent (Evonik Ancamide 2353).

[0024] The preparation method of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating is the same as in Example 1.

[0025] Comparative Example 1 is a commercially available conventional epoxy zinc-rich primer (Jotun's Barrier 97 epoxy zinc-rich primer; the product has a zinc powder content (in dry film) ≥80%, which meets the requirements of ISO 12944-5 C5-M for corrosive environments).

[0026] Comparative Example 2: Ordinary graphene epoxy coating (SE-EP-01 general-purpose graphene epoxy anti-corrosion coating from Changzhou Sixth Element Materials Technology Co., Ltd., which adds non-functional graphene to improve general anti-corrosion performance).

[0027] Comparative Example 3 contains no graphene. Component A includes the following raw materials by mass fraction: bisphenol F epoxy resin (EPIKOTE of Hexion, USA). TM 862) 40%; flake zinc powder (ZNY-201 from Eckart, Germany, aspect ratio >50) 20%; mica iron oxide (HJ-Y-2 from Shanghai Huijingya, flake diameter 30μm) 16%; sericite powder (GR-80 from Chuzhou Gerui) 5%; dispersant (BYK-2150) 1%; defoamer (BYK-141) 0.5%; leveling agent (BYK-331) 0.5%; mixed solvent (PMA / 150 solvent oil = 1:1) 17%; the rest are the same as in Example 1.

[0028] Comparative Example 4 was designed to verify the physical shielding advantages of flake-shaped zinc powder. The flake-shaped zinc powder was replaced with an equal mass of ordinary spherical zinc powder (Dust 47 from Grillo, Germany, with an average particle size of 5 μm). All other components, proportions, and preparation methods were the same as in Example 1.

[0029] Test Experiment Example The graphene coatings of Examples 1-4 were mixed with those of Comparative Examples 1-4 as required and mechanically stirred for 5 minutes until uniform. The coatings were then uniformly applied to a low-carbon steel Q235 test plate (150mm×70mm×3mm) that had been sandblasted to Sa2.5 and had a surface roughness Ra of 50μm±10μm using a wire bar coater. The wet film thickness was controlled at 200μm, and the coating was cured for 7 days under standard conditions of (23±2)℃ and (50±5)% relative humidity to form a coating sample with a dry film thickness of 120±10μm for performance testing.

[0030] Salt spray resistance was tested according to GB / T 1771-2007 "Determination of resistance to neutral salt spray in paints and varnishes", with samples checked every 50 hours; adhesion (cross-cut test) was determined according to GB / T9286-2021 "Cross-cut test in paints and varnishes"; artificial weathering resistance was determined according to GB / T 1865-2009 "Artificial weathering and artificial radiation exposure in paints and varnishes", with 340nm xenon arc lamp irradiation and samples checked every 24 hours; VOC content was determined according to GB / T 23985-2009 "Determination of volatile organic compound (VOC) content in paints and varnishes"; and cathodic disbondment radius was determined according to NACE TM0304-2014 "Cathode stripping test method for pipe coatings". The results are shown in Table 1.

[0031] Table 1. Detection results of Examples 1-4 and Comparative Examples 1-4 As can be seen from Table 1, the coating of the present invention is significantly superior to traditional products in terms of anti-corrosion life, adhesion, weather resistance and environmental protection. Its salt spray resistance time is ≥6000h, its adhesion (cross-cut test) is grade 0, and its artificial climate aging resistance is ≥4000h. It is especially suitable for long-term protection in marine environments and meets the stringent requirements of the shipbuilding and marine engineering fields for high-end anti-corrosion coatings.

[0032] The protection provided by Comparative Example 1 relies entirely on the sacrificial anode cathodic protection effect of high zinc content powder. This is a consumable protection method. Once the conductive zinc particle network in the coating is blocked by non-conductive corrosion products, the cathodic protection effect immediately fails, and corrosion will occur rapidly at the damage point. The coating formed by the accumulation of high content spherical zinc powder has a high porosity, resulting in a shorter penetration path for the corrosive medium. The high zinc content powder leads to greater brittleness of the coating and relatively low adhesion. Toxic zinc mist is generated during welding, and the zinc-containing waste residue after coating failure is hazardous waste with high treatment costs. The epoxy resin matrix is ​​prone to powdering and yellowing under ultraviolet light, and high zinc content powder has no effect on improving this. Example 1 of this invention adopts a synergistic protection strategy of "appropriate amount of zinc powder (about 20%) cathodic protection + flake filler / graphene physical shielding + chemical functionalization modification"; the flake zinc powder, mica iron oxide, sericite and graphene form a highly oriented, layer-by-layer dense physical barrier in the coating, which greatly prolongs the penetration path of the corrosive medium; even if a small amount of zinc powder is consumed, the physical shielding effect of the coating remains effective for a long time, achieving a more balanced and durable coating performance.

[0033] The non-functionalized graphene in Comparative Example 2, due to its extremely high specific surface area and strong π-π interactions, is prone to agglomeration in the resin matrix and is difficult to disperse. Agglomerated graphene forms discontinuous conductive aggregates in the coating, which may locally form microscopic galvanic cells with the metal matrix, accelerating localized corrosion. Ordinary graphene only undergoes physical adsorption with the resin matrix, resulting in weak interfacial bonding and easy debonding under mechanical stress or environmental aging, leading to protective failure. In Example 2 of this invention, the amino functional groups of the "amino-graphene dispersion" exhibit better compatibility and potential chemical reactivity with the epoxy resin matrix and curing agent, ensuring that graphene is uniformly dispersed in monolayers or a few layers, exerting its "two-dimensional barrier" effect. The amino groups can react with the epoxy groups, chemically bonding the graphene into the cross-linked network, greatly enhancing interfacial strength and improving the overall mechanical properties and durability of the coating. The uniformly dispersed amino-graphene can synergistically form a more uniform and stable conductive network with the zinc flake powder, promoting the uniform distribution of cathodic protection current.

[0034] Comparative Example 3 completely lacks graphene components. Although it contains flake-like zinc powder and mica iron oxide, the lack of atomically thick graphene sheets for "gap filling" and "zigzag paths" ultimately enhances the coating's density, resulting in significantly higher water vapor and oxygen permeability compared to the embodiments of this invention. The conductive network performance is also insufficient: relying solely on flake zinc powder to provide the cathodic protection conductive network limits its efficiency and stability. Furthermore, the absence of graphene reduces the coating's impact resistance and chemical resistance. Embodiment 3 of this invention, by introducing trace amounts of highly dispersed aminated graphene, achieves a multi-scale, multi-dimensional composite shielding system ranging from the micrometer scale (mica iron oxide, sericite) to the nanometer scale. Graphene acts like an extremely robust and inert "nanoplastic mortar" added to the flake-like "brick wall" structure, strengthening the protective barrier and unifying functionality (conductivity, enhancement) with protection.

[0035] Comparative Example 4 uses spherical zinc powder instead of flake zinc powder, completely changing the geometry and stacking method of the filler. The spherical particles are stacked in a "point contact" manner, forming numerous through-pores, allowing water, oxygen, and ions to penetrate the substrate relatively linearly. However, its salt spray resistance is far inferior to that of Example 4 of this invention. The high density of spherical zinc powder makes it prone to settling and clumping during storage, affecting workability and coating uniformity. The conductive network formed by spherical zinc powder is less continuous and stable than that of flake zinc powder, potentially leading to uneven cathodic protection current distribution. One of the core innovations of Example 4 of this invention is the preferred use of "flake zinc powder with a diameter-to-thickness ratio > 50." This sheet-like structure is arranged parallel to the substrate in the coating, like countless tiny "shields" stacked layer upon layer, transforming the penetration path of the corrosive medium from a straight line into an extremely tortuous "maze path," which is fundamental to its ultra-long salt spray resistance life. The sheet-like structure facilitates suspension and slows settling. Furthermore, the sheet-like structure is more easily interconnected, forming a low-resistance two-dimensional conductive plane, which couples with the two-dimensional conductive network of graphene to construct a highly efficient and stable cathodic protection system.

[0036] This invention (Examples 1-4) is based on a system design of "synergistic enhancement and functional coupling": flake-like zinc powder + flake-like mica iron oxide / sericeous mica + two-dimensional graphene constructs an ultimate "maze" shielding structure from micrometers to nanometers; the flake-like zinc powder and aminated graphene jointly construct a highly efficient and stable conductive network to achieve long-lasting cathodic protection; at the same time, all the flake-like fillers jointly undertake the important task of physical barrier; by aminated functional modification of graphene, the problems of its dispersion and interfacial bonding are solved. This invention achieves a balance between long-lasting effect, stability and ease of application through formulation and process design.

Claims

1. A long-life, weather-resistant, heavy-duty anti-corrosion graphene coating, characterized in that, It consists of two components, A and B, in a mass ratio of 100:(10-15); Component A includes the following raw materials in the following mass fractions: bisphenol F epoxy resin: 30%-45%, amino-based graphene dispersion: 3%-8%, flake zinc powder: 15%-25%, mica iron oxide: 10%-20%, sericite powder: 3%-8%, dispersant: 0.5%-1.5%, defoamer: 0.2%-0.8%, leveling agent: 0.3%-1.0%, and mixed solvent: 10%-20%; Component B is a polyamide curing agent; The aminated graphene dispersion is a dispersion of aminated graphene in water, alcohol or other organic solvents prepared by modification with a silane coupling agent, wherein the mass content of aminated graphene is 0.5% to 5%, the graphene sheet diameter is 5 to 15 μm, the number of layers is 1 to 5, and the mass percentage of amino functional groups in the aminated graphene is 0.5 to 1.5 at.

2. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The bisphenol F epoxy resin is prepared by reacting phenol and formaldehyde under acidic catalysis to generate bisphenol F, and then carrying out a polycondensation reaction with epichlorohydrin in the presence of sodium hydroxide. The epoxy value is 0.15-0.25 eq / 100g, and the viscosity at 25℃ is 2000-7000 cps.

3. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The flaky zinc powder has an aspect ratio > 40:1, a particle size of 200-800 mesh, and a purity ≥ 99.9%.

4. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The mica iron oxide has a flaky structure with a particle size distribution of 10–50 μm.

5. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The sericite powder is fine-grained, scaly white mica with a diameter-to-thickness ratio >80 and a particle size of 200–2000 mesh.

6. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The dispersant is a high molecular block copolymer containing anchoring groups; the defoamer is an organosilicon defoamer; the leveling agent is an organosilicon surfactant; and the mixed solvent is a compound of propylene glycol methyl ether acetate and No. 150 solvent oil in a mass ratio of 1:1 to 1:

2.

7. The long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, The polyamide curing agent is a modified polyamide curing agent with an amine value of 280-350 mg KOH / g and a viscosity of 2000-3500 mPa·s at 25℃.

8. The method for preparing the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to any one of claims 1 to 7, characterized in that, The preparation steps for component A include the following: (1) Add the phenolic modified epoxy resin to the mixed solvent of the specified amount, and then add the dispersant, defoamer and leveling agent, and stir to mix evenly; (2) Add the flake-shaped zinc powder, mica iron oxide and sericite powder in sequence, and stir to mix evenly; (3) Add the aminated graphene dispersion and stir until the graphene is uniformly dispersed and free of agglomeration; (4) Adjust the viscosity to 60-90s with the remaining mixed solvent, filter, and obtain component A.

9. The method for preparing the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 8, characterized in that, Step (1) involves stirring at a speed of 400-600 r / min for 10-15 minutes to ensure uniform mixing of the raw materials; Step (2) involves stirring at a speed of 800-1200 r / min for 20-30 minutes to ensure uniform mixing of the raw materials; Step (3) involves stirring at a speed of 600-800 r / min for 30-45 minutes.

10. The method for preparing the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to claim 1, characterized in that, In step (3), a disc-type dispersion disc is used for stirring and dispersion. The linear velocity of the dispersion disc is 10-15 m / s, and the system temperature is controlled below 40℃ during the dispersion process.

11. The application of the long-life, weather-resistant, heavy-duty anti-corrosion graphene coating according to any one of claims 1 to 7 in the protection of steel structures of ships, offshore platforms, port facilities and coastal bridges.

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