Graphene nano long-acting anticorrosive coating and preparation method thereof

Abstract

The application discloses graphene nano long-acting anticorrosive paint and a preparation method thereof, and relates to the technical field of anticorrosive paint, and comprises 100 parts of epoxy resin and 1.0 parts of a functionalized graphene mixture; the functionalized graphene mixture comprises component 1, flexible interface-aminosilane functionalized graphene, and component 2, long-chain alkyl grafted hydrophobic graphene; wherein the relative weight proportion of component 2 in the functionalized graphene mixture is defined as the weight of component 2 / (the weight of component 1 + the weight of component 2), and is in the range of 0.1 to 0.4. The application realizes the synergy of double functionalized graphene, and combines gradient curing and thickness-proportion self-adaptive adjustment. The obtained coating has excellent internal stress buffering capacity, stable surface hydrophobicity and wide adaptability to different construction thicknesses, and has excellent comprehensive anticorrosive performance.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to graphene nano-long-lasting anti-corrosion coatings and their preparation methods. Background Technology

[0002] Epoxy resin-based coatings are among the most widely used coating systems in the industrial anti-corrosion field. These coatings protect the substrate by forming a dense physical barrier layer on the surface of the metal substrate, isolating corrosive media such as water molecules, oxygen, and chloride ions. However, after traditional epoxy resins cure into a film, their three-dimensional cross-linked network inevitably contains micropores or defects. These pores provide penetration channels for corrosive media. To improve the barrier effect, anti-corrosion pigments, such as high proportions of zinc powder, are often added industrially. However, high amounts of zinc powder not only significantly increase the cost of the coating but also easily lead to a decline in the mechanical properties of the coating, such as increased brittleness, and pose environmental risks of heavy metal pollution. Therefore, the development of novel, efficient, and environmentally friendly anti-corrosion fillers has become a research hotspot in this field. In recent years, graphene, as a two-dimensional nanomaterial, has been considered an ideal filler for constructing efficient physical barriers due to its excellent sheet structure and chemical stability. Theoretically, two-dimensional graphene sheets can form a labyrinth effect in the resin matrix, greatly extending the penetration path of corrosive media, thereby significantly improving the long-term anti-corrosion performance of the coating.

[0003] However, the practical application effects of graphene have fallen far short of theoretical expectations. First, the extremely strong van der Waals forces and π-π stacking interactions between graphene sheets make them prone to severe agglomeration in polar matrices such as epoxy resins, making effective nanoscale dispersion difficult. Second, the unfunctionalized graphene surface is chemically inert and hydrophobic, exhibiting extremely poor compatibility with epoxy resin matrices. Effective interfacial bonding cannot be formed between the two, and these graphene agglomerates and poor interfaces become new defects in the coating, providing high-speed channels for corrosive media and accelerating coating failure. To address the dispersion and compatibility issues, existing technologies attempt to modify the surface of graphene, but often focus only on a single mechanism, such as achieving only a physical barrier, while neglecting the stress cracking problem caused by the mismatch in thermal expansion coefficients between the coating and the substrate when subjected to extreme temperature cycling in actual working conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a graphene nano-long-lasting anti-corrosion coating and its preparation method, thereby solving the problems existing in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides a graphene nano-long-lasting anti-corrosion coating, which, by weight, comprises 100 parts of epoxy resin and 1.0 part of functionalized graphene mixture.

[0006] Functionalized graphene mixtures include:

[0007] Component 1: Flexible interface-aminosilane functionalized graphene; and

[0008] Component 2: Long-chain alkyl-grafted hydrophobic graphene;

[0009] The relative weight ratio of component 2 in the functionalized graphene mixture is defined as the weight of component 2 / (weight of component 1 + weight of component 2), which is in the range of 0.1 to 0.4.

[0010] Preferably, the relative weight ratio is adaptively adjusted according to the target dry film thickness;

[0011] When the target dry film thickness is ≤50μm, the relative weight ratio is 0.4; when 50μm < target dry film thickness ≤150μm, the relative weight ratio is 0.2; when the target dry film thickness >150μm, the relative weight ratio is 0.1.

[0012] Preferably, the flexible interface-aminosilane functionalized graphene is prepared by the following method:

[0013] (1) Flexible linking branches: Graphene oxide slurry is dispersed in N,N-dimethylformamide and ultrasonically treated; then polyetheramine is added and the temperature is raised to 105~115°C to react and graft flexible segments.

[0014] (2) Silanization grafting: Cool the reaction solution of step (1) to 75~85°C, add ethanol / water mixed solvent and 3-aminopropyltriethoxysilane, and carry out reflux reaction at the temperature to graft terminal amine groups;

[0015] (3) Product purification: After cooling the reaction solution in step (2), centrifuge, wash, and vacuum dry at 55~65°C to obtain flexible interface-aminosilane functionalized graphene.

[0016] Preferably, the polyetheramine in step (1) is D-400 type polyetheramine; and the volume ratio of ethanol / water mixed solvent in step (2) is 9:1.

[0017] Preferably, long-chain alkyl-grafted hydrophobic graphene is prepared by the following method:

[0018] (1) Activation: Take the graphene oxide dispersion, add N-hydroxysuccinimide and N,N-dicyclohexylcarbodiimide, stir and react at room temperature for 10~14 hours to activate the -COOH groups on the surface of graphene oxide.

[0019] (2) Amide grafting: Add dodecylamine to the above system, heat to 65~75°C and stir for 20~28 hours;

[0020] (3) Product purification: The reaction product was centrifuged, washed and dried to obtain long-chain alkyl-grafted hydrophobic graphene.

[0021] Preferably, the epoxy resin is E-51 type epoxy resin.

[0022] A method for preparing a graphene nano-long-lasting anti-corrosion coating is also provided, comprising the following steps:

[0023] (1) Weigh out component 1 and component 2 according to the specified ratio and add them to the epoxy resin;

[0024] (2) Use a high-speed shear disperser to shear disperse for 30 to 50 minutes at a speed of 2000 to 3000 rpm;

[0025] (3) Transfer to an ultrasonic cell disruptor for ultrasonic dispersion treatment;

[0026] (4) Under the conditions of vacuum degree of -0.08~-0.10MPa and temperature of 40~50°C, the coating composition is obtained by standing and degassing for 80~100 minutes.

[0027] Preferably, the power of ultrasonic dispersion treatment in step (3) is 450~550W, and a cycle mode of working for 2~4 seconds and intermittent for 1~3 seconds is adopted, with a total time of 50~70 minutes.

[0028] Preferably, it includes the following steps:

[0029] (5) The prepared coating composition is mixed with the polyamide curing agent in a stoichiometric ratio to obtain a mixed coating;

[0030] (6) Apply the mixed coating to the surface of the substrate;

[0031] (7) A gradient curing process is used on the substrate coated with the mixed coating. The gradient curing process includes:

[0032] (a) Migration window period: Keep warm at 38~42°C for 50~70 minutes;

[0033] (b) Network lock zone: Increase the temperature program to 98~102°C and keep it warm for 110~130 minutes.

[0034] Preferably, in step (5), the weight ratio of the coating composition to the polyamide curing agent is 100:25.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] By introducing a flexible interface—aminosilane functionalized graphene—not only is the dispersibility and compatibility of graphene in epoxy resin improved, but the terminal active groups can also participate in the curing and crosslinking reaction of the resin to form a stable chemical bond interface. The flexible chain segment structure introduced into the component can build a stress buffer mechanism inside the coating, effectively absorbing and dissipating the thermal stress caused by temperature changes, significantly improving the coating's ability to resist thermal shock and extreme temperature cycling, and preventing the coating from cracking due to brittleness.

[0037] By introducing long-chain alkyl-grafted hydrophobic graphene components and employing a gradient curing process, a specific low-temperature migration window is set to ensure that the hydrophobic components have sufficient time to accumulate on the coating surface before the resin network locks in. This endows the coating surface with excellent and stable hydrophobic properties, enabling it to actively repel water molecules. On the basis of an efficient physical barrier, an active anti-corrosion mechanism is added, further hindering the intrusion of corrosive media.

[0038] A thickness-ratio adaptive adjustment scheme is provided. By dynamically adjusting the relative weight ratio between the flexible interface component and the hydrophobic component according to the target dry film thickness, it ensures that the coating can achieve an optimized balance between surface hydrophobicity and bulk barrier properties under both thin and thick coating application conditions. This makes the coating more widely applicable to industry and has greater process stability, meeting the high-performance anti-corrosion requirements of different construction scenarios. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] Example 1 (Application of Reference Thickness)

[0041] The graphene nano-long-lasting anti-corrosion coating of this embodiment comprises, by weight, 100 parts epoxy resin and 1.0 part functionalized graphene mixture; unless otherwise stated, the raw materials used in the embodiments and comparative examples of this invention, such as E-51 type epoxy resin, D-400 type polyetheramine, 3-aminopropyltriethoxysilane, N-hydroxysuccinimide, N,N-dicyclohexylcarbodiimide, dodecylamine and polyamide curing agent, are all conventional industrial products that can be purchased from the market;

[0042] The functionalized graphene mixture includes component 1 (flexible interface-aminosilane functionalized graphene) and component 2 (long-chain alkyl grafted hydrophobic graphene); for the construction scenario with a baseline thickness of 50μm < target dry film thickness < 150μm (set to 100μm in this example), the relative weight ratio of component 2 in the functionalized graphene mixture is set to 0.2, that is, it contains 0.8 parts of component 1 and 0.2 parts of component 2;

[0043] The flexible interface-aminosilane functionalized graphene was prepared by the following method: (1) Graphene oxide slurry was dispersed in N,N-dimethylformamide, ultrasonically treated, and then D-400 type polyetheramine was added. The temperature was raised to 110°C to react and graft flexible segments; (2) The temperature was cooled to 80°C, and ethanol / water (volume ratio 9:1) mixed solvent and 3-aminopropyltriethoxysilane were added. The reaction was refluxed at this temperature to graft terminal amino groups; (3) Product purification: The reaction solution was cooled, centrifuged, washed, and vacuum dried at 60°C.

[0044] Long-chain alkyl-grafted hydrophobic graphene was prepared by the following method: (1) Take graphene oxide dispersion, add N-hydroxysuccinimide and N,N-dicyclohexylcarbodiimide, stir at room temperature for 12 hours to activate the -COOH group; (2) Add dodecylamine, heat to 70°C and stir for 24 hours; (3) Purify the product: centrifuge, wash and dry the reaction product;

[0045] The preparation method of the coating in this embodiment includes: (1) weighing and adding 0.8 parts of component 1 and 0.2 parts of component 2 into 100 parts of E-51 epoxy resin; (2) using a high-speed shear disperser, shearing and dispersing at 2500 rpm for 40 minutes; (3) transferring to an ultrasonic cell disruptor, using a 500W power, working for 3 seconds and intermittent for 2 seconds, for a total ultrasonic dispersion treatment time of 60 minutes; (4) standing for degassing at a vacuum of -0.09 MPa and a temperature of 45°C for 90 minutes to obtain the coating composition;

[0046] When applying, (5) mix the coating composition and the polyamide curing agent at a weight ratio of 100:25; (6) apply the mixed coating to the surface of the substrate; (7) apply a gradient curing process to the coated substrate: (a) migration window period: keep at 40°C for 60 minutes; (b) network locking zone: program the temperature to 100°C and keep at 120 minutes;

[0047] The coating prepared in this embodiment constructs a stress buffering mechanism in the epoxy matrix through a flexible interface component (component 1), while the gradient curing process ensures that the hydrophobic component (component 2) effectively migrates to the surface. This coating is suitable for scenarios such as ships and bridges that are subjected to medium-thickness coatings and complex environments, and exhibits good corrosion resistance and thermal shock resistance.

[0048] Example 2 (Thin Coating Application)

[0049] The graphene nano-long-lasting anti-corrosion coating of this embodiment has the same formulation and preparation process as that of Example 1. The difference is that it is designed for thin coating applications with a target dry film thickness of <50μm (40μm in this example). The relative weight ratio is adaptively adjusted according to the target dry film thickness and set to 0.4. That is, 1.0 part of functionalized graphene mixture includes 0.6 parts of component 1 and 0.4 parts of component 2.

[0050] Process parameter selection: In the preparation of component 1, the flexible linking grafting temperature is 105°C, and the silanization grafting temperature is 75°C; in the preparation of component 2, the activation reaction is 10 hours, and the amidation grafting reaction is 20 hours; in the preparation of the coating composition, the high-speed shearing speed is 2000 rpm, and the time is 30 minutes; the ultrasonic power is 450W, with a working time of 2 seconds and an intermittent time of 1 second, and a total time of 50 minutes; the degassing vacuum degree is -0.08MPa, the temperature is 40°C, and the time is 80 minutes; the gradient curing process is: (a) 38°C for 50 minutes; (b) heating to 98°C and holding for 110 minutes;

[0051] This embodiment ensures that, even with a thinner dry film thickness, sufficient hydrophobic components migrate to the surface to form a dense hydrophobic barrier by increasing the relative weight ratio of the hydrophobic components. This coating is suitable for corrosion protection of precision equipment or lightweight components with high requirements for surface hydrophobicity and limited coating thickness, providing active water repellency while maintaining a good physical barrier.

[0052] Example 3 (Thick Coating Application)

[0053] The graphene nano-long-lasting anti-corrosion coating of this embodiment has the same formulation and preparation process as that of Example 1. The difference is that it is designed for thick coating applications with a target dry film thickness >150μm (set to 160μm in this example). The relative weight ratio is adaptively adjusted according to the target dry film thickness and set to 0.1. That is, 1.0 part of functionalized graphene mixture includes 0.9 parts of component 1 and 0.1 parts of component 2.

[0054] Process parameter selection: In the preparation of component 1, the flexible linking grafting temperature is 115°C, and the silanization grafting temperature is 85°C; in the preparation of component 2, the activation reaction is 14 hours, and the amidation grafting reaction is 28 hours; in the preparation of the coating composition, the high-speed shearing speed is 3000 rpm, and the time is 50 minutes; the ultrasonic power is 550W, with a working time of 4 seconds and an intermittent time of 3 seconds, and a total time of 70 minutes; the degassing vacuum degree is -0.10MPa, the temperature is 50°C, and the time is 100 minutes; the gradient curing process is: (a) 42°C for 70 minutes; (b) heating to 102°C and holding for 130 minutes;

[0055] This embodiment reduces the proportion of the hydrophobic component (component 2) and increases the proportion of the flexible interface component (component 1). This is because in thick coatings, the physical barrier effect of the bulk phase (provided by component 1 and the resin network) is more critical, while preventing excessive hydrophobic components from being trapped in the bulk phase and affecting internal crosslinking. This coating is suitable for heavy-duty anti-corrosion applications that require a single thick coating, such as offshore platform pile foundations and large storage tanks, focusing on providing excellent internal crosslinking networks and stress buffering capabilities to resist long-term immersion and structural stress. Example 4

[0056] The graphene nano-long-lasting anti-corrosion coating of this embodiment has a formula and preparation process that are basically the same as those of Example 1 (target dry film thickness 100μm, relative weight ratio = 0.2).

[0057] Process parameter selection: In the preparation of component 1, the flexible linking grafting temperature is 108°C, and the silanization grafting temperature is 78°C; in the preparation of component 2, the activation reaction is 13 hours, and the amidation grafting reaction is 26 hours; in the preparation of the coating composition, the high-speed shearing speed is 2800 rpm, and the time is 45 minutes; the ultrasonic power is 520W, the working time is 2.5 seconds, the interval is 1.5 seconds, and the total time is 65 minutes; the degassing vacuum degree is -0.085MPa, the temperature is 42°C, and the time is 85 minutes; the gradient curing process is: (a) 41°C for 65 minutes; (b) heating to 101°C and holding for 125 minutes;

[0058] This embodiment verifies that a stable coating can still be prepared under the baseline ratio when the process parameters fluctuate within a defined range; its effect is similar to that of Example 1, and it is suitable for general anti-corrosion coating in standard industrial production environments, demonstrating the stability and reliability of the process. Example 5

[0059] The graphene nano-long-lasting anti-corrosion coating of this embodiment has a formula and preparation process that are basically the same as those of Example 1 (target dry film thickness 100μm, relative weight ratio = 0.2).

[0060] Process parameter selection: In the preparation of component 1, the flexible linking grafting temperature is 112°C, and the silanization grafting temperature is 82°C; in the preparation of component 2, the activation reaction is 11 hours, and the amidation grafting reaction is 22 hours; in the preparation of the coating composition, the high-speed shearing speed is 2200 rpm, and the time is 35 minutes; the ultrasonic power is 480W, the working time is 3.5 seconds, the interval is 2.5 seconds, and the total time is 55 minutes; the degassing vacuum degree is -0.095MPa, the temperature is 48°C, and the time is 95 minutes; the gradient curing process is: (a) 39°C for 55 minutes; (b) heating to 99°C and holding for 115 minutes;

[0061] This embodiment also verifies the feasibility of different process parameter combinations under the baseline ratio; the coating performance is similar to that of Examples 1 and 4, indicating that the process window of the present invention is wide, easy to implement in industrial applications, and can meet the production needs under different equipment conditions.

[0062] Comparative Example 1

[0063] The same 100 parts of epoxy resin and 25 parts of polyamide curing agent as in Example 1 were mixed, without adding any graphene functionalized mixture; the curing process was the same as in Example 1 (40°C / 60min+100°C / 120min).

[0064] Comparative Example 2

[0065] The formulation and preparation process are basically the same as those in Example 1. The difference is that when preparing component 1 (flexible interface-aminosilane functionalized graphene), the step of adding polyetheramine in step (1) is omitted, that is, the silanization grafting in step (2) is carried out directly; this results in component 1 not having flexible interface segments.

[0066] Comparative Example 3

[0067] The formulation and preparation process are exactly the same as in Example 1, but after the coating composition is mixed with the polyamide curing agent and coated, a different curing process is used: gradient curing is canceled, and the coated substrate is directly placed in a 100°C oven for 120 minutes to cure.

[0068] Performance testing and effect analysis

[0069] To verify the technical effects of the embodiments of the present invention compared with the comparative examples, performance tests were conducted on the coatings prepared in the above embodiments and comparative examples;

[0070] 1. Electrochemical Impedance Spectroscopy (EIS) Measurement

[0071] After immersing the coating in a 3.5% NaCl solution for 7 days, its low-frequency (0.01Hz) impedance modulus (Z0.01Hz) was tested. This value is the core indicator for evaluating the physical barrier performance of the coating. The higher the impedance value, the stronger the coating's ability to block corrosive media (water, oxygen, ions).

[0072] 2. Hydrophobicity test of coating surface (water contact angle)

[0073] Examples of gradient curing processes and Comparative Example 3, which uses direct high-temperature curing, were tested for the static water contact angle of their coating surfaces; this indicator was used to verify the effectiveness of the gradient curing process for enriching the surface of hydrophobic components (component 2).

[0074] 3. Coating flexibility and thermal shock resistance test

[0075] The coating was subjected to cyclic thermal shock testing between -40°C and +60°C (simulating extreme day-night temperature difference scenarios). After 30 cycles, the coating surface was observed to see if microcracks appeared or the adhesion decreased. This indicator was used to verify the stress buffering effect of the flexible segments in the flexible interface-aminosilane functionalized graphene (component 1).

[0076] Table 1 Summary of Performance Test Results

[0077]

[0078] Effect Analysis (Comparison Process)

[0079] Corrosion resistance performance (EIS comparison): The low-frequency impedance of Examples 1, 2, and 3 all reached [specific values]. Order of magnitude, relative to Comparative Example 1 (pure epoxy coating, The impedance was increased by about three orders of magnitude; this confirms that the functionalized graphene mixture (component 1 + component 2) of the present invention forms a highly efficient physical barrier network in epoxy resin, which significantly hinders the penetration of corrosive media.

[0080] Flexible interface effect (thermal shock comparison): The coating of Example 1 (containing flexible segments) remained intact after 30 thermal shock cycles, while the coating of Comparative Example 2 (without flexible polyetheramine segments) developed microcracks after 10 cycles. This shows that the flexible interface-amine silane functionalized graphene introduced into Component 1 of this invention does indeed play a stress buffering role, effectively absorbing the stress caused by the mismatch between thermal expansion and contraction between the substrate and the coating, and improving the reliability of the coating under extreme temperature cycling scenarios.

[0081] Gradient curing and hydrophobicity (contact angle comparison): Example 1, using a gradient curing process, achieved a water contact angle of 106°; while Comparative Example 3 (using direct high-temperature curing) had a water contact angle of only 85°. This clearly shows that direct high-temperature curing leads to a rapid increase in resin viscosity, and the hydrophobic component (component 2) is frozen in the bulk phase before it can migrate to the surface. The gradient curing process of this invention, especially the migration window period (e.g., 40°C heat preservation), provides the necessary low-viscosity environment and migration time for the hydrophobic component, ensuring its effective enrichment on the coating surface, thereby endowing the coating with the ability to actively repel moisture.

[0082] Thickness-ratio adaptive effect: Both Example 2 (thin coating, R=0.4) and Example 3 (thick coating, R=0.1) exhibited similar high impedance and target hydrophobicity (or internal crosslinking) as Example 1; this shows that the scheme of adaptively adjusting the relative weight ratio according to the target dry film thickness proposed in this invention is effective; this scheme (the relative ratio is negatively correlated with the thickness d) ensures the balance between the hydrophobicity of the coating surface and the bulk barrier under different construction thicknesses, and solves the technical problem of inconsistent performance of traditional fixed formulations under different construction conditions;

[0083] In summary, this invention, through the synergistic effect of dual-functional graphene (flexible interface + hydrophobic modification), combined with thickness-ratio adaptive and gradient curing process control, prepares a graphene nano-long-lasting anti-corrosion coating that simultaneously solves the problems of coating thermal shock brittleness, surface hydrophobicity, and application adaptability to different thicknesses, thus obtaining an anti-corrosion coating with excellent comprehensive performance.

[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A graphene nano-long-lasting anti-corrosion coating, characterized in that: By weight, it includes 100 parts epoxy resin and 1.0 part functionalized graphene mixture; Functionalized graphene mixtures include: Component 1: Flexible interface-aminosilane functionalized graphene; and Component 2: Long-chain alkyl-grafted hydrophobic graphene; The relative weight ratio of component 2 in the functionalized graphene mixture is defined as the weight of component 2 / (weight of component 1 + weight of component 2), which is in the range of 0.1 to 0.

4. The relative weight ratio is adaptively adjusted according to the target dry film thickness; When the target dry film thickness is ≤50μm, the relative weight ratio is 0.4; when 50μm < target dry film thickness ≤150μm, the relative weight ratio is 0.2; when the target dry film thickness >150μm, the relative weight ratio is 0.

1. Flexible interface-aminosilane functionalized graphene is prepared by the following method: (1) Flexible linking branches: Graphene oxide slurry is dispersed in N,N-dimethylformamide and ultrasonically treated; then polyetheramine is added and the temperature is raised to 105~115°C to react and graft flexible segments. (2) Silanization grafting: Cool the reaction solution of step (1) to 75~85°C, add ethanol / water mixed solvent and 3-aminopropyltriethoxysilane, and carry out reflux reaction at the temperature to graft terminal amine groups; (3) Product purification: After cooling the reaction solution in step (2), centrifuge, wash, and vacuum dry at 55~65°C to obtain flexible interface-aminosilane functionalized graphene. Long-chain alkyl-grafted hydrophobic graphene was prepared by the following method: (1) Activation: Take the graphene oxide dispersion, add N-hydroxysuccinimide and N,N-dicyclohexylcarbodiimide, stir and react at room temperature for 10~14 hours to activate the -COOH groups on the surface of graphene oxide. (2) Amide grafting: Add dodecylamine, heat to 65~75°C and stir for 20~28 hours; (3) Product purification: The reaction product was centrifuged, washed and dried to obtain long-chain alkyl-grafted hydrophobic graphene; The preparation method of graphene nano-long-lasting anti-corrosion coating includes the following steps: (1) Weigh out component 1 and component 2 according to the specified ratio and add them to the epoxy resin; (2) Use a high-speed shear disperser to shear disperse for 30 to 50 minutes at a speed of 2000 to 3000 rpm; (3) Transfer to an ultrasonic cell disruptor for ultrasonic dispersion treatment; (4) Under a vacuum of -0.08 to -0.10 MPa and a temperature of 40 to 50°C, the mixture is allowed to stand for 80 to 100 minutes to remove bubbles, and the coating composition is obtained. (5) The prepared coating composition is mixed with the polyamide curing agent in a stoichiometric ratio to obtain a mixed coating; (6) Apply the mixed coating to the surface of the substrate; (7) A gradient curing process is used on the substrate coated with the mixed coating. The gradient curing process includes: (a) Migration window period: Keep warm at 38~42°C for 50~70 minutes; (b) Network lock zone: Increase the temperature program to 98~102°C and keep it warm for 110~130 minutes.

2. The graphene nano-long-lasting anti-corrosion coating according to claim 1, characterized in that, In step (1), the polyetheramine is type D-400 polyetheramine; in step (2), the volume ratio of ethanol / water mixed solvent is 9:

1.

3. The graphene nano-long-lasting anti-corrosion coating according to claim 1, characterized in that, The epoxy resin is type E-51 epoxy resin.

4. The graphene nano-long-lasting anti-corrosion coating according to claim 1, characterized in that, In step (3), the power of ultrasonic dispersion treatment is 450~550W, and a cycle of working for 2~4 seconds and intermittent for 1~3 seconds is adopted, with a total time of 50~70 minutes.

5. The graphene nano-long-lasting anti-corrosion coating according to claim 1, characterized in that, In step (5), the weight ratio of the coating composition to the polyamide curing agent is 100:25.

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