Ultralow-temperature-resistant seawater-corrosion-resistant coating and preparation method thereof

Abstract

The invention discloses an ultralow-temperature-resistant and seawater-corrosion-resistant coating and a preparation method thereof. The ultralow-temperature-resistant and seawater-corrosion-resistant coating is prepared from ultralow-temperature-resistant and seawater-corrosion-resistant finish paint and graphene epoxy zinc-rich primer, the ultralow-temperature-resistant seawater-corrosion-resistant finish paint is prepared from a component A and a component B, wherein the component A is prepared from the following raw materials: low-temperature-resistant epoxy resin, fluorocarbon resin, graphene, nano rare earth oxide, a silane coupling agent, an anti-rust pigment, filler, a solvent and the like; the component B is composed of an amine curing agent, and the low-temperature-resistant epoxy resin is prepared according to the following steps: adding epoxy resin and polysiloxane into a reaction kettle, stirring and reacting while heating, adding epoxidized hydroxyl-terminated polybutadiene into the reaction kettle, and continuously stirring and reacting to obtain the low-temperature-resistant epoxy resin. The ultralow-temperature-resistant and seawater-corrosion-resistant coating disclosed by the invention has excellent corrosion resistance in ultralow-temperature seawater, and the service life of a metal structure is effectively prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anticorrosive coatings, in particular to a super-low-temperature-resistant and seawater-corrosion-resistant coating and a preparation method thereof. BACKGROUND

[0002] Traditional coatings often fail to play an effective protective role in the combined environment of super-low temperature and high corrosion. Most existing anticorrosive coatings are designed for normal temperature or general industrial environment, and have many defects in low-temperature seawater environment. For example, some coatings will crack and peel at low temperature, exposing the metal substrate directly to seawater and accelerating the corrosion process. Although some coatings have certain corrosion resistance at normal temperature, their chemical stability deteriorates at low temperature, and they cannot prevent the corrosion of chloride ions.

[0003] With the continuous development of marine resource development, such as the advancement of deep-sea oil and gas exploitation, submarine cable laying and other projects, and the increase of polar shipping, scientific research station construction and other activities, marine facilities (such as ships) are being used more and more widely, and higher requirements for the corrosion protection of marine facilities are also being put forward. Traditional coatings often become brittle and have reduced adhesion in super-low temperature environment, and are difficult to effectively resist the corrosion of chloride ions and other substances under long-term seawater immersion, resulting in damage to the metal substrate and seriously affecting the service life and safety of the equipment. On the one hand, in the marine environment, seawater is rich in salt, and chloride ions have strong corrosive properties, can penetrate ordinary protective coatings, cause electrochemical corrosion of metals, and lead to a decrease in the strength of metal structures, damage or even failure. On the other hand, in low-temperature environments, especially in polar sea areas, seawater temperature is often below 0℃, and can even reach below -70℃. Low temperature can change the physical properties of metal materials, making them more brittle, and also affect the adhesion and flexibility of the coating.

[0004] The development of super-low-temperature-resistant and seawater-corrosion-resistant coatings has become one of the key technologies to ensure the safe operation of marine engineering facilities, prolong the service life and reduce maintenance costs, and has important significance for promoting the sustainable development of marine economy and scientific exploration in polar regions. Therefore, there is an urgent need to develop a coating that can meet both the super-low-temperature requirement and the seawater-corrosion-resistant requirement, and can stably protect metal structures in super-low-temperature seawater environment for a long time. SUMMARY

[0005] To solve the above problems, the purpose of the present application is to provide a super-low-temperature-resistant and seawater-corrosion-resistant coating and a preparation method thereof, which can maintain good corrosion resistance in super-low-temperature environment and effectively prolong the service life of metal structures.

[0006] To achieve the above purpose, the present application realizes the following technical solutions:

[0007] The application discloses a super-low-temperature-resistant seawater corrosion-resistant coating which is composed of a super-low-temperature-resistant seawater corrosion-resistant topcoat and a graphene epoxy zinc-rich primer.

[0008] The A component is composed of the following raw materials in parts by weight: a low-temperature-resistant epoxy resin 20-50 parts, a fluorocarbon resin 5-20 parts, first graphene 3-6 parts, nano rare earth oxide 1-3 parts, a silane coupling agent 1-2 parts, anti-rust pigment 8-12 parts, filler 10-20 parts, first defoaming agent 0.5-2 parts, first leveling agent 0.1-1 part, first dispersing agent 0.1-1 part, first wetting agent 0.1-1 part, compatibilizer 0.2-1 part, corrosion inhibitor 0.5-3 parts and first solvent 20-30 parts.

[0009] The B component is composed of the following raw materials: first amine curing agent 10-15 parts.

[0010] The low-temperature-resistant epoxy resin is prepared according to the following steps:

[0011] The epoxy resin and polysiloxane are added into a reaction kettle, and stirring reaction is carried out at 80-100 DEG C for 3-5 hours; then the epoxidized hydroxyl-terminated polybutadiene is added into the reaction kettle, and continues to be stirred and reacted for 1-2 hours to obtain the low-temperature-resistant epoxy resin; wherein the mass ratio of the epoxy resin, the polysiloxane and the epoxidized hydroxyl-terminated polybutadiene is 60-90:10-40:3-10.

[0012] Preferably, the nano rare earth oxide is one or two of nano cerium oxide, nano lanthanum oxide or nano lanthanum cerium oxide.

[0013] The silane coupling agent is one or two of KH550, KH560, KH570 or KH792.

[0014] The compatibilizer is one or two of FC-4430, KBE-403, FS-63 or GF91.

[0015] The corrosion inhibitor is one or two of zinc phosphate, calcium zinc phosphate, zinc molybdate, zinc borate or lithium silicate.

[0016] Preferably, the fillers are three, four or five of precipitated barium sulfate, red iron oxide, sericite, talc, light calcium carbonate or kaolin; wherein the precipitated barium sulfate improves the wear resistance and the hardness of the coating, plays a role of physical barrier to improve the corrosion resistance; the red iron oxide can react with the resin or moisture in the coating to form a dense oxide film, isolate the metal substrate from the corrosive medium, prevent electrochemical corrosion, and improve the corrosion resistance, while also having the function of pigments to color and hide; the sericite forms a multi-layer "labyrinth" barrier layer with a flaky structure, significantly prolonging the penetration path of moisture, oxygen and salt, and enhancing the corrosion protection effect; the talc reduces the shrinkage of the coating, enhances the density of the coating, and improves the construction performance and corrosion resistance; the light calcium carbonate adjusts the viscosity of the coating and slightly improves the wear resistance of the coating; the kaolin improves the suspension performance of the coating, increases the density of the coating, and reduces the penetration of corrosive media;

[0017] The various fillers do not act alone, but through synergistic effects such as physical shielding (flaky structure), chemical rust prevention (red iron oxide), mechanical reinforcement (barium sulfate, talc), performance adjustment (calcium carbonate, kaolin), etc., to improve the corrosion life, mechanical strength and construction applicability of the coating.

[0018] The rust-proof pigment is mica iron oxide, zinc phosphate, aluminum tripolyphosphate or zinc chrome yellow;

[0019] The first defoaming agent is one or two of HY-141, DS8750, HDK H30LM, EFKA-2020 or TEGO AIREX 900;

[0020] The first leveling agent is one or two of T-50, TEGO Glide 410, BYK-370 or Hyperlev F20;

[0021] The first dispersing agent is one or two of TEGO Dispers 700, EFKA-4010 or BYK-104s;

[0022] The first wetting agent is one or two of CZ-D3010, 505S or TEGO 4100;

[0023] The first amine curing agent is polyamide 300#, polyamide 650#, isophorone diamine, diethylene triamine or diethyl toluene diamine;

[0024] The first solvent is toluene, xylene, n-butyl acetate, N-75 desmocoll or cyclohexanone.

[0025] Preferably, the epoxy resin is E44 or E51.

[0026] Preferably, the graphene zinc-rich epoxy primer is composed of a C component and a D component;

[0027] The C component is composed of the following raw materials in parts by weight: low-temperature-resistant epoxy resin 15-25 parts, zinc powder 20-60 parts, second graphene 1-5 parts, second solvent 8-15 parts, anti-settling agent 1-2 parts, second dispersing agent 0.5-1 part, second defoaming agent 0.5-2 parts, second leveling agent 0.1-1 part, and second wetting agent 0.1-1 part;

[0028] The D component is composed of a second amine curing agent 8-25 parts.

[0029] Preferably, the second solvent is toluene, xylene, n-butyl acetate, N-75 Desmodur, or cyclohexanone;

[0030] The anti-settling agent is fumed silica or organic bentonite;

[0031] The second amine curing agent is polyamide 300#, polyamide 650#, isophorone diamine, diethylene triamine, or diethyl toluene diamine.

[0032] Preferably, the second dispersing agent is one or two of TEGO Dispers 700, EFKA-4010, or BYK-104s;

[0033] The second defoaming agent is one or two of HY-141, DS8750, HDK H30LM, EFKA-2020, or TEGO AIREX 900;

[0034] The second leveling agent is one or two of T-50, TEGO Glide 410, BYK-370, or Hyperlev F20;

[0035] The second wetting agent is one or two of CZ-D3010, 505S, or TEGO 4100.

[0036] The present application also includes a preparation method of an ultra-low-temperature-resistant and seawater-corrosion-resistant coating, and the ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat is prepared according to the following steps:

[0037] Preparation of the A component:

[0038] ① In parts by weight, 3-6 parts of first graphene, 1-3 parts of nano-rare earth oxide, and 20-30 parts of first solvent are added to an ultrasonic cleaning machine, and ultrasonic treatment is performed for 30-60 minutes to obtain a uniform nano-dispersion liquid;

[0039] ②In the dispersing machine, 20-50 parts of low-temperature resistant epoxy resin, 5-20 parts of fluorocarbon resin and 0.2-1 part of compatibility agent are added, and stirred at 20-30 DEG C for 1-2 hours to mix uniformly, to obtain a mixed resin liquid;

[0040] ③The uniform nanodispersion liquid obtained in step 1 is added to the mixed resin liquid obtained in step 2, and stirred for 30-45 minutes, then 1-2 parts of silane coupling agent, 8-12 parts of anti-rust pigment, 10-20 parts of filler, 0.5-2 parts of first defoaming agent, 0.1-1 part of first leveling agent, 0.1-1 part of first dispersing agent, 0.1-1 part of first wetting agent and 0.5-3 parts of corrosion inhibitor are added, and dispersed in the dispersing machine for 15-40 minutes, then added to a grinding machine and ground to a fineness of less than 15 microns, to obtain component A;

[0041] Preparation of component B: 10-15 parts of first amine curing agent;

[0042] In use, the obtained component A and component B are mixed, and cured at 80-120 DEG C for 1-2 hours to obtain the ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat.

[0043] Preferably, the graphene epoxy zinc-rich primer is prepared according to the following steps:

[0044] Preparation of component C: in the dispersing machine, 15-25 parts of low-temperature resistant epoxy resin, 20-60 parts of zinc powder, 1-5 parts of second graphene, 8-15 parts of second solvent, 1-2 parts of anti-settling agent, 0.5-1 part of second dispersing agent, 0.5-2 parts of second defoaming agent, 0.1-1 part of second leveling agent and 0.1-1 part of second wetting agent are added, and stirred and dispersed for 15-60 minutes, then added to a grinding machine and ground to a fineness of less than 15 microns, to obtain component C;

[0045] Preparation of component D: 8-25 parts of second amine curing agent;

[0046] In use, the obtained component C and component D are mixed, and cured at 80-120 DEG C for 1-2 hours to obtain the graphene epoxy zinc-rich primer.

[0047] Compared with the prior art, the present application has the following advantages:

[0048] The ultra-low-temperature-resistant and seawater-corrosion-resistant coating can have excellent corrosion resistance in ultra-low temperature (up to -70 DEG C) seawater, and effectively prolongs the service life of metal structures.

[0049] Firstly, the low-temperature resistant epoxy resin is obtained by grafting reaction of epoxy resin and polysilazane after reaction, and epoxidized hydroxyl-terminated polybutadiene; wherein the introduction of silazane gives the main chain high thermal stability and low temperature resistance by inorganic silicon-oxygen bond, and the organic group of epoxy resin increases the flexibility, the organic and inorganic segments on the main chain spontaneously form a nanoscale phase separation structure, the inorganic silicon-rich phase constitutes a rigid region, and plays a physical node role; the random flexible organic segment in the crosslinked network can maintain a certain mobility at low temperature; this unique molecular topological structure gives the polysilazane epoxy cured product excellent resistance to extremely low temperature, and further, the addition of epoxidized hydroxyl-terminated polybutadiene improves the flexibility of the epoxy resin at low temperature.

[0050] Secondly, the fluorocarbon resin is added in the topcoat containing the low-temperature resistant epoxy resin, and cooperates with the low-temperature resistant epoxy resin. On the one hand, the polar groups such as epoxy group and hydroxyl group in the epoxy resin can form chemical bonds with the substrates such as metal (such as the hydroxyl group on the surface of steel), concrete and the like, and the adhesion strength far exceeds that of most resins, and after crosslinking, a dense three-dimensional network structure is formed, which can effectively block the penetration of corrosion media such as water, oxygen and chloride ions, but the C-C bond and C-O bond in the molecular structure are easily damaged by ultraviolet light, and long-term outdoor exposure will cause powdering and cracking, resulting in failure of the coating; on the other hand, the fluorocarbon resin molecule contains a large number of C-F bonds, which can resist ultraviolet light, ozone, high temperature and other aging factors, and the outdoor service life can reach more than 20 years, and it is resistant to strong acid, strong base and strong oxidizing agent, and even can resist the corrosion of some organic solvents, but the C-F bond has weak polarity, and the interaction with the surface of the substrate is weak, and it is easy to fall off when used alone. The present application achieves the cooperation of adhesion and weather resistance by compounding the low-temperature resistant epoxy resin with the fluorocarbon resin, so as to ensure that the coating is not easy to fall off and has good weather resistance. The dense crosslinked structure of the epoxy resin can effectively intercept small molecule corrosion media, the low surface energy of the fluorocarbon resin can reduce the wetting of water on the surface of the coating, and the corrosion resistance is synergistically enhanced; at the same time, the chemical inertness of the fluorocarbon chain can avoid the reaction of the corrosion medium with the resin itself.

[0051] Finally, in the topcoat containing the low-temperature resistant epoxy resin, the addition of graphene and nano-rare earth oxide not only improves the hardness and wear resistance of the coating, but also prolongs the corrosion path and enhances the seawater corrosion resistance, which can effectively block the penetration of chloride ions; the antirust pigment further enhances the protection of the metal substrate, prolonging the service life of the metal parts in seawater environment. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 Figure is a grid method adhesion test diagram after liquid nitrogen immersion for 7 days;

[0053] Figure 2 Figure is a grid method adhesion test diagram after liquid nitrogen immersion for 7 days;

[0054] Figure 3 Flexibility (4mm) test pattern (another angle) was drawn after soaking in liquid nitrogen for 7 days. DETAILED DESCRIPTION

[0055] The application aims to provide a super-low-temperature-resistant and seawater-corrosion-resistant coating and a preparation method thereof.

[0056] In use, the topcoat and the primer are sprayed according to the corrosion prevention requirements, the thickness of the topcoat is about 200 μm for light corrosion prevention and 300-500 μm for heavy corrosion prevention, the thickness of the primer is 40-60 μm for light corrosion prevention and 80-120 μm for heavy corrosion prevention.

[0057] Example 1

[0058] A super-low-temperature-resistant and seawater-corrosion-resistant coating is composed of a super-low-temperature-resistant and seawater-corrosion-resistant topcoat and a graphene epoxy zinc-rich primer.

[0059] The A component is composed of the following raw materials: 20 kg of low-temperature-resistant epoxy resin, 5 kg of fluorocarbon resin, 3 kg of graphene, 1 kg of nano cerium oxide, 1 kg of silane coupling agent KH550, 8 kg of anti-rust pigment zinc chrome yellow, 3 kg of precipitated barium sulfate, 3 kg of iron oxide red, 4 kg of kaolin, 0.5 kg of defoaming agent HY-141, 0.1 kg of leveling agent T-500, 0.1 kg of dispersing agent TEGO Dispers 7000, 0.1 kg of wetting agent CZ-D301, 0.2 kg of compatibilizer FC-443, 0.5 kg of corrosion inhibitor zinc phosphate and 20 kg of toluene.

[0060] The B component is composed of the following raw materials: 10 kg of amine curing agent polyamide 300#.

[0061] The graphene epoxy zinc-rich primer is composed of a C component and a D component.

[0062] The C component is composed of the following raw materials: 15 kg of low-temperature-resistant epoxy resin, 20 kg of zinc powder, 1 kg of graphene, 8 kg of toluene, 1 kg of anti-settling agent fumed silica, 0.5 kg of dispersing agent TEGO Dispers 7000, 0.5 kg of defoaming agent HY-141, 0.1 kg of leveling agent T-500 and 0.1 kg of wetting agent CZ-D301.

[0063] The D component is composed of 8 kg of amine curing agent polyamide 300#.

[0064] The low-temperature-resistant epoxy resin is prepared by the following steps:

[0065] 30kg of epoxy resin E51 and 5kg of polysiloxane are added to a reaction kettle, and stirred at 80℃ for 3 hours, 1.5kg of epoxidized hydroxyl-terminated polybutadiene is added to the reaction kettle for continuous stirring for 1 hour to obtain a low-temperature-resistant epoxy resin.

[0066] Example 2

[0067] A super-low-temperature-resistant seawater corrosion-resistant coating is composed of a super-low-temperature-resistant seawater corrosion-resistant topcoat and a graphene epoxy zinc-rich primer; the super-low-temperature-resistant seawater corrosion-resistant topcoat is composed of component A and component B:

[0068] The component A is composed of the following raw materials: 50kg of low-temperature-resistant epoxy resin, 20kg of fluorocarbon resin, 6kg of graphene, 3kg of nano lanthanum oxide, 2kg of silane coupling agent KH560, 12kg of antirust pigment mica iron oxide, 5kg of sericite, 8kg of talc, 7kg of red iron oxide, 2kg of defoaming agent DS8750, 1kg of leveling agent TEGO Glide 410, 1kg of dispersant EFKA-4010, 1kg of wetting agent 505S, 1kg of compatibilizer compatibilizer FC-4430, and 3kg of corrosion inhibitor zinc calcium phosphate and 30kg of xylene;

[0069] The component B is composed of the following raw materials: 15kg of amine curing agent polyamide 650#;

[0070] The graphene epoxy zinc-rich primer is composed of component C and component D:

[0071] The component C is composed of the following raw materials: 25kg of low-temperature-resistant epoxy resin, 60kg of zinc powder, 5kg of graphene, 15kg of xylene, 2kg of anti-settling agent organic bentonite, 1kg of dispersant EFKA-4010, 2kg of defoaming agent DS8750, 1kg of leveling agent TEGO Glide 410, and 1kg of wetting agent 505S;

[0072] The component D is composed of 25kg of amine curing agent polyamide 650#;

[0073] The low-temperature-resistant epoxy resin is prepared according to the following steps:

[0074] 54kg of epoxy resin E51 and 24kg of polysiloxane are added to a reaction kettle, and stirred at 100℃ for 5 hours, 6kg of epoxidized hydroxyl-terminated polybutadiene is added to the reaction kettle for continuous stirring for 2 hours to obtain a low-temperature-resistant epoxy resin.

[0075] Example 3

[0076] The application discloses a super-low-temperature-resistant seawater corrosion-resistant paint which is composed of a super-low-temperature-resistant seawater corrosion-resistant topcoat and a graphene zinc-rich epoxy primer.

[0077] The A component is composed of 30 kg of low-temperature-resistant epoxy resin, 10 kg of fluorocarbon resin, 4 kg of graphene, 1.5 kg of nano lanthanum cerium oxide, 1.2 kg of silane coupling agent KH570, 9 kg of anti-rust pigment zinc phosphate, 0.8 kg of defoaming agent HDK H30LM, 0.4 kg of leveling agent BYK-3700, 0.4 kg of dispersant BYK-104s, 0.4 kg of wetting agent TEGO 4100, 0.5 kg of compatibilizer KBE-403 and 0.6 kg of corrosion inhibitor zinc molybdate, 22 kg of n-butyl acetate and fillers, wherein the types and mass ratios of the fillers are shown in Table 1.

[0078] The B component is composed of 12 kg of isophorone diamine.

[0079] The graphene zinc-rich epoxy primer is composed of a C component and a D component.

[0080] The C component is composed of 18 kg of low-temperature-resistant epoxy resin, 30 kg of zinc powder, 2 kg of graphene, 9 kg of n-butyl acetate, 1.2 kg of anti-settling agent fumed silica, 0.6 kg of dispersant BYK-104s, 0.6 kg of defoaming agent HDK H30LM, 0.4 kg of leveling agent BYK-3700 and 0.8 kg of wetting agent TEGO 4100.

[0081] The D component is composed of 10 kg of amine curing agent isophorone diamine.

[0082] The low-temperature-resistant epoxy resin is prepared according to the following steps.

[0083] 40 kg of epoxy resin E51 and 15 kg of polysiloxane are added into a reaction kettle, and stirring reaction is carried out at 85 DEG C for 4 hours, 3 kg of epoxidized hydroxyl-terminated polybutadiene is added into the reaction kettle, and stirring reaction is continuously carried out for 1.5 hours, so that the low-temperature-resistant epoxy resin is obtained.

[0084] Different fillers have different effects on the performance of the application, and the fillers of the application are selected in different types to form different embodiments, as shown in Table 1.

[0085] Table 1 shows the selection table of the fillers.

[0086] No. Filler Example 3-1 Talc 4 kg, light calcium carbonate 4 kg, kaolin 4 kg Example 3-2 Precipitated barium sulfate 5 kg, red iron oxide 3 kg, sericite 3 kg Example 3-3 Red iron oxide 3 kg, sericite 6 kg, talc 4 kg Example 3-4 Sericite 5 kg, talc 5 kg, light calcium carbonate 5 kg Example 3-5 Precipitated barium sulfate 4 kg, sericite 3 kg, talc 6 kg

[0087] Example 4

[0088] The anti-ultra-low-temperature and seawater corrosion resistant coating is composed of an anti-ultra-low-temperature and seawater corrosion resistant topcoat and a graphene epoxy zinc-rich primer.

[0089] The A component is composed of 25 kg of low-temperature resistant epoxy resin, 8 kg of fluorocarbon resin, 5 kg of graphene, 1 kg of nano cerium oxide, 1 kg of nano lanthanum oxide, 1 kg of silane coupling agent KH570, 0.8 kg of silane coupling agent KH792, 11 kg of anti-rust pigment zinc phosphate, 0.8 kg of defoamer HY-14, 1 kg of defoamer DS8750, 0.3 kg of leveling agent T-500, 0.4 kg of leveling agent TEGO Glide41, 0.3 kg of dispersant TEGO Dispers 7000, 0.5 kg of dispersant EFKA-4010, 0.2 kg of wetting agent CZ-D301, 0.2 kg of wetting agent 505S, 0.4 kg of compatibilizer GF9, and 1 kg of corrosion inhibitor zinc borate, 1 kg of corrosion inhibitor lithium silicate, 28 kg of cyclohexanone, and a filler, wherein the types and mass ratios of the filler are shown in Table 2.

[0090] The B component is composed of 11 kg of amine curing agent diethylenetriamine.

[0091] The graphene epoxy zinc-rich primer is composed of a C component and a D component.

[0092] The C component is composed of 22 kg of low-temperature resistant epoxy resin, 50 kg of zinc powder, 4 kg of graphene, 10 kg of cyclohexanone, 1.5 kg of anti-settling agent organic bentonite, 0.3 kg of dispersant TEGO Dispers 7000, 0.5 kg of dispersant EFKA-4010, 1.2 kg of defoamer polyoxypropylene-polyoxyethylene glycerol ether, 0.8 kg of leveling agent Hyperlev F2, 0.2 kg of wetting agent CZ-D301, and 0.3 kg of wetting agent 505S.

[0093] The D component is composed of 15 kg of amine curing agent diethylenetriamine.

[0094] The low-temperature resistant epoxy resin is prepared according to the following steps:

[0095] 33 kg of epoxy resin E44 and 13 kg of polysiloxane are added to a reaction kettle, and stirring reaction is carried out at 85°C for 4 hours, 4 kg of epoxidized hydroxyl-terminated polybutadiene is added to the reaction kettle, and stirring reaction is continued for 100 minutes to obtain the low-temperature resistant epoxy resin.

[0096] Different fillers have different effects on the performance of the present technology, and the fillers of the present technology are selected in different types to form different embodiments, as shown in Table 2.

[0097] Table 2 Selection table of fillers

[0098] No. Filler Example 4-1 Precipitated barium sulfate 3 kg, talc 2 kg, light calcium carbonate 8 kg, red iron oxide 5 kg Example 4-2 Precipitated barium sulfate 5 kg, red iron oxide 3 kg, sericite 2 kg, talc 2 kg Example 4-3 Red iron oxide 3 kg, sericite 3 kg, talc 4 kg, light calcium carbonate 4 kg Example 4-4 Sericite 5 kg, talc 5 kg, light calcium carbonate 5 kg and kaolin 5 kg Example 4-5 Precipitated barium sulfate 4 kg, sericite 3 kg, talc 2 kg, light calcium carbonate 3 kg

[0099] Example 5

[0100] An ultra-low temperature resistant and seawater corrosion resistant paint is composed of an ultra-low temperature resistant and seawater corrosion resistant topcoat and a graphene epoxy zinc-rich primer. The ultra-low temperature resistant and seawater corrosion resistant topcoat is composed of component A and component B:

[0101] The component A is composed of the following raw materials: low-temperature resistant epoxy resin 45 kg, fluorocarbon resin 16 kg, graphene 4.5 kg, nano lanthanum oxide 1 kg, nano lanthanum cerium oxide 1.5 kg, silane coupling agent KH560 1 kg, silane coupling agent KH570 0.6 kg, anti-rust pigment aluminum tripolyphosphate 10 kg, defoamer HY-141 0.8 kg, defoamer TEGO AIREX 90 0.7 kg, leveling agent BYK-370 0.3 kg, leveling agent Hyperlev F2 0.2 kg, dispersant EFKA-40 100.1 kg, dispersant BYK-104s 0.5 kg, wetting agent 505S 0.5 kg, wetting agent TEGO 4100 0.3 kg, compatibilizer FS-6 0.1 kg, N-aminoethyl-3-aminopropyl trifluoropropyl silane 0.4 kg, corrosion inhibitor zinc phosphate 1 kg, corrosion inhibitor calcium zinc phosphate 1 kg, and xylene 25 kg and fillers, wherein the types and mass ratios of the fillers are shown in Table 3;

[0102] The component B is composed of the following raw materials: amine curing agent diethyl toluene diamine 14 kg;

[0103] The graphene epoxy zinc-rich primer is composed of component C and component D:

[0104] The component C is composed of the following raw materials: low-temperature resistant epoxy resin 18 kg, zinc powder 30 kg, graphene 3 kg, xylene 11 kg, anti-settling agent fumed silica 1.4 kg, dispersant EFKA-40 100.3 kg, dispersant BYK-104s 0.3 kg, defoamer HY-141 0.5 kg, defoamer DS8750 1 kg, leveling agent TEGO Glide 410 0.2 kg, leveling agent BYK-370 0.4 kg, wetting agent CZ-D301 0.4 kg, wetting agent TEGO 4100 0.4 kg;

[0105] The component D is composed of amine curing agent diethyl toluene diamine 20 kg

[0106] The low-temperature resistant epoxy resin is prepared according to the following steps:

[0107] 65 kg of epoxy resin E44 and 14 kg of polysiloxane were added into a reaction kettle, and stirring reaction was carried out at 95℃ for 4 hours, 4 kg of hydroxyl-terminated polybutadiene was added into the reaction kettle to continue stirring reaction for 1.5 hours, and a low-temperature-resistant epoxy resin was obtained.

[0108] Different fillers have different effects on the performance of the present technology, and the fillers of the present technology can form different embodiments by selecting different types, as shown in Table 3.

[0109] Table 3: Selection table of fillers

[0110]

[0111]

[0112] Example 6

[0113] The preparation method of the ultra-low-temperature-resistant and seawater-corrosion-resistant coating of Example 1 comprises the following steps:

[0114] (1) Preparation of an ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat: comprising the following steps:

[0115] Preparation of component A:

[0116] ① 3 kg of graphene, 1 kg of nano cerium oxide and 20 kg of toluene were added into an ultrasonic cleaning machine, and ultrasonic treatment was carried out for 30 minutes to obtain a uniform nanodispersion liquid;

[0117] ② 20 kg of low-temperature-resistant epoxy resin, 5 kg of fluorocarbon resin and 0.2 kg of compatibilizer FC-4430 were added into a dispersing machine, and stirring was carried out at 20℃ for 1 hour to obtain a mixed resin liquid;

[0118] ③ The uniform nanodispersion liquid obtained in step ① was added into the mixed resin liquid obtained in step ②, and stirring was continued for 30-45 minutes, then 1 kg of silane coupling agent KH550, 8 kg of anti-rust pigment zinc chrome yellow, 3 kg of precipitated barium sulfate, 3 kg of iron oxide red, 4 kg of kaolin, 0.5 kg of defoaming agent HY-141, 0.1 kg of leveling agent T-500, 0.1 kg of dispersing agent TEGO Dispers 7000, 0.1 kg of wetting agent CZ-D3010 and 0.5 kg of corrosion inhibitor zinc phosphate were added, and dispersion was carried out in the dispersing machine for 15 minutes, then it was added into a grinding machine and ground to a fineness of less than 15 microns to obtain component A;

[0119] Preparation of component B: amine curing agent polyamide 300# 10 kg;

[0120] In use, the obtained component A and component B are mixed, and an ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat is obtained after curing at 80℃ for 2 hours. (2) Preparation of a graphene epoxy zinc-rich primer, comprising the following steps:

[0121] Preparation of C component: add low temperature resistant epoxy resin 15 kg, zinc powder 20 kg, graphene 1 kg, toluene 8 kg, anti-settling agent fumed silica 1 kg, dispersant TEGO Dispers 7000.5 kg, defoamer HY-141 0.5 kg, leveling agent T-500 0.1 kg, wetting agent CZ-D301 0.1 kg into a disperser, disperse for 15 minutes, then add to a grinder, grind to a fineness of less than 15 microns to obtain C component;

[0122] Preparation of D component: amine curing agent polyamide 300# 8 kg;

[0123] In use, the obtained C component and D component are mixed, and the graphene zinc-rich epoxy primer is cured at 80°C for 2 hours.

[0124] Example 7

[0125] The preparation method of the ultra-low temperature resistant and seawater corrosion resistant paint of Example 2 comprises the following steps:

[0126] (1) Preparation of ultra-low temperature resistant and seawater corrosion resistant topcoat: comprising the following steps:

[0127] Preparation of A component:

[0128] ① Add graphene 6 kg, nano lanthanum oxide 3 kg and dimethylbenzene 30 kg into an ultrasonic cleaner, and ultrasonic for 30-60 minutes to obtain a uniform nanodispersion;

[0129] ② Add low temperature resistant epoxy resin 50 kg, fluorocarbon resin 20 kg, low temperature resistant epoxy resin 20-50 parts, fluorocarbon resin 5-20 parts and compatibilizer compatibilizer FC-4430 1 kg into a disperser, mix uniformly at 30°C for 2 hours to obtain a mixed resin solution;

[0130] ③ Add the uniform nanodispersion obtained in step ① into the mixed resin solution obtained in step ②, continue to stir for 45 minutes, then add silane coupling agent KH560 2 kg, anti-rust pigment mica iron oxide 12 kg, sericite 5 kg, talc 8 kg, red iron oxide 7 kg, defoamer DS8750 2 kg, leveling agent TEGO Glide 410 1 kg, dispersant EFKA-4010 1 kg, wetting agent 505S 1 kg, and corrosion inhibitor zinc calcium phosphate 3 kg into the disperser, disperse for 40 minutes, then add to a grinder, grind to a fineness of less than 15 microns to obtain A component;

[0131] Preparation of B component: amine curing agent polyamide 650# 15 kg;

[0132] In use, the obtained A component and B component are mixed, and the ultra-low temperature resistant and seawater corrosion resistant topcoat is cured at 90°C for 1.5 hours.

[0133] (2) Preparation of graphene epoxy zinc-rich primer, comprising the following steps:

[0134] Preparation of C component: add low-temperature resistant epoxy resin 25 kg, zinc powder 60 kg, graphene 5 kg, dimethylbenzene 15 kg, anti-settling agent organic bentonite 2 kg, dispersant EFKA-4010 1 kg, defoaming agent DS8750 2 kg, leveling agent TEGO Glide 410 1 kg, wetting agent 505S 1 kg into a disperser and stir and disperse for 60 minutes, then add to a grinder and grind to a fineness of less than 15 microns to obtain the C component;

[0135] Preparation of D component: amine curing agent polyamide 650# 25 kg;

[0136] In use, the obtained C component and D component are mixed, and the graphene epoxy zinc-rich primer is cured at 90°C for 1.5 hours.

[0137] Example 8

[0138] The preparation method of the ultra-low temperature resistant and seawater corrosion resistant coating of Example 3 comprises the following steps:

[0139] (1) Preparation of ultra-low temperature resistant and seawater corrosion resistant topcoat: comprising the following steps:

[0140] Preparation of A component:

[0141] ① Add graphene 4 kg, nano lanthanum cerium oxide 1.5 kg and n-butyl acetate 22 kg into an ultrasonic cleaner, and ultrasonic for 40 minutes to obtain a uniform nano dispersion liquid;

[0142] ② Add low-temperature resistant epoxy resin 30 kg, fluorocarbon resin 10 kg and compatibilizer KBE-403 0.5 kg into a disperser, stir at 25°C for 1.5 hours to mix uniformly, and obtain a mixed resin liquid;

[0143] ③ Add the uniform nano dispersion liquid obtained in step ① into the mixed resin liquid obtained in step ②, continue to stir for 35 minutes, then add silane coupling agent KH570 1.2 kg, anti-rust pigment zinc molybdate 9 kg, defoaming agent HDK H30LM 0.8 kg, leveling agent BYK-370 0.4 kg, dispersant BYK-104s 0.4 kg, wetting agent TEGO 4100 0.4 kg, corrosion inhibitor zinc molybdate 0.6 kg and fillers (composition as shown in Table 1) into the disperser, disperse for 30 minutes, then add to a grinder and grind to a fineness of less than 15 microns to obtain the A component;

[0144] Preparation of B component: isophorone diamine 12 kg;

[0145] In use, the resulting A component and B component are mixed, and the ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat is cured at 100°C for 1 hour;

[0146] Preparation of C component: add low-temperature-resistant epoxy resin 18 kg, zinc powder 30 kg, graphene 2 kg, n-butyl acetate 9 kg, anti-settling agent fumed silica 1.2 kg, dispersant BYK-104s 0.6 kg, defoamer HDK H30LM 0.6 kg, leveling agent BYK-370 0.4 kg, wetting agent TEGO 4100 0.8 kg into a disperser, stir and disperse for 40 minutes, then add to a grinder, grind to a fineness of less than 15 microns to obtain the C component;

[0147] Preparation of D component: isophorone diamine 10 kg;

[0148] In use, the resulting C component and D component are mixed, and the graphene epoxy zinc-rich primer is cured at 100°C for 1 hour.

[0149] Example 9

[0150] The preparation method of the ultra-low-temperature-resistant and seawater-corrosion-resistant coating of Example 4 includes the following steps:

[0151] (1) Preparation of ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat: including the following steps:

[0152] Preparation of A component:

[0153] ① Add graphene 5 kg, nano cerium oxide 1 kg, nano lanthanum oxide 1 kg, and cyclohexanone 28 kg into an ultrasonic cleaner, and ultrasonic for 55 minutes to obtain a uniform nano dispersion liquid;

[0154] ② Add low-temperature-resistant epoxy resin 25 kg, fluorocarbon resin 8 kg, and compatibilizer GF9 0.4 kg into a disperser, stir at 24°C for 1.5 hours to mix evenly to obtain a mixed resin liquid;

[0155] (3) Adding the uniform nanodispersion obtained in step (1) into the mixed resin solution obtained in step (2), continuing to stir for 30-45 minutes, then adding silane coupling agent KH570 1 kg, silane coupling agent KH79 2 kg, anti-rust pigment zinc phosphate 11 kg, defoaming agent HY-14 10.8 kg, defoaming agent DS8750 1 kg, leveling agent T-500 0.3 kg, leveling agent TEGO Glide41 0.4 kg, dispersant TEGO Dispers 7000 0.3 kg, dispersant EFKA-40 100.5 kg, wetting agent CZ-D30 100.2 kg, wetting agent 505S 0.2 kg, corrosion inhibitor zinc borate 1 kg, corrosion inhibitor lithium silicate 1 kg, and fillers (composition as shown in Table 2) into a disperser and dispersing for 35 minutes, then adding into a grinder and grinding to a fineness of less than 15 microns to obtain component A;

[0156] Preparation of component B: amine curing agent diethylenetriamine 11 kg;

[0157] In use, the obtained component A and component B are mixed, and a super-low-temperature-resistant and seawater-corrosion-resistant topcoat is obtained after curing at 90°C for 2 hours.

[0158] Preparation of component C: adding low-temperature-resistant epoxy resin 22 kg, zinc powder 50 kg, graphene 4 kg, cyclohexanone 10 kg, anti-settling agent organic bentonite 1.5 kg, dispersant TEGO Dispers 7000 0.3 kg, dispersant EFKA-40 100.5 kg, defoaming agent polyoxypropylene-polyoxyethylene glycerol ether 1.2 kg, leveling agent Hyperlev F2 0.8 kg, wetting agent CZ-D30 100.2 kg, and wetting agent 505S 0.3 kg into a disperser and stirring and dispersing for 50 minutes, then adding into a grinder and grinding to a fineness of less than 15 microns to obtain component C;

[0159] Preparation of component D: amine curing agent diethylenetriamine 15 kg;

[0160] In use, the obtained component C and component D are mixed, and a graphene epoxy zinc-rich primer is obtained after curing at 90°C for 2 hours.

[0161] Example 10

[0162] The preparation method of the super-low-temperature-resistant and seawater-corrosion-resistant coating of Example 5 comprises the following steps:

[0163] (1) Preparation of a super-low-temperature-resistant and seawater-corrosion-resistant topcoat: comprising the following steps:

[0164] Preparation of component A:

[0165] ① Put graphene 4.5 kg, nano lanthanum oxide 1 kg, nano lanthanum cerium oxide 1.5 kg and dimethylbenzene 25 kg into an ultrasonic cleaning machine, and ultrasonic for 50 minutes to obtain a uniform nano dispersion liquid;

[0166] ② Put low-temperature-resistant epoxy resin 45 kg, fluorocarbon resin 16 kg and compatibility agent FS-630 0.5 kg into a dispersing machine, and stir at 24℃ for 1.5 hours to mix uniformly to obtain a mixed resin liquid;

[0167] ③ Put the uniform nano dispersion liquid obtained in step ① into the mixed resin liquid obtained in step ②, continue to stir for 35 minutes, then add silane coupling agent KH560 1 kg, silane coupling agent KH570 0.6 kg, anti-rust pigment aluminum tripolyphosphate 10 kg, defoaming agent HY-141 0.8 kg, defoaming agent TEGO AIREX 900 0.7 kg, leveling agent BYK-370 0.3 kg, leveling agent Hyperlev F2 0.2 kg, dispersant EFKA-401 0.1 kg, dispersant BYK-104s 0.5 kg, wetting agent 505S 0.5 kg, wetting agent TEGO 4100 0.3 kg, corrosion inhibitor zinc phosphate 1 kg, corrosion inhibitor calcium zinc phosphate 1 kg and filler (composition as shown in Table 3) into the dispersing machine, and disperse for 35 minutes, then add into a grinding machine, and grind to a fineness less than 15 microns to obtain component A;

[0168] Prepare component B: amine curing agent diethyl toluene diamine 14 kg;

[0169] When used, mix the obtained component A and component B, and cure at 110℃ for 1.5 hours to obtain an ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat;

[0170] (2) Preparation of graphene epoxy zinc-rich primer, comprising the following steps:

[0171] Prepare component C: put low-temperature-resistant epoxy resin 18 kg, zinc powder 30 kg, graphene 3 kg, dimethylbenzene 11 kg, anti-settling agent fumed silica 1.4 kg, dispersant EFKA-401 0.3 kg, dispersant BYK-104s 0.3 kg, defoaming agent HY-141 0.5 kg, defoaming agent DS8750 1 kg, leveling agent TEGO Glide 410 0.2 kg, leveling agent BYK-370 0.4 kg, wetting agent CZ-D301 0.4 kg, and wetting agent TEGO 4100 0.4 kg into a dispersing machine, and stir and disperse for 40 minutes, then add into a grinding machine, and grind to a fineness less than 15 microns to obtain component C;

[0172] Prepare component D: amine curing agent diethyl toluene diamine 20 kg;

[0173] In use, the obtained C component and D component are mixed, and the graphene epoxy zinc-rich primer is cured at 110℃ for 1.5 hours.

[0174] The ultra-low-temperature-resistant and seawater-corrosion-resistant coatings of examples 6-10 are used in use, and the topcoat and primer are sprayed according to the corrosion prevention requirements. The thickness of the topcoat is about 200μm for light corrosion prevention and 300-500μm for heavy corrosion prevention. The thickness of the primer is 40-60μm for light corrosion prevention and 80-120μm for heavy corrosion prevention.

[0175] The ultra-low-temperature-resistant and seawater-corrosion-resistant coatings obtained in examples 6-10 are tested for performance. According to the crosshatch adhesion test (GB / T 9286-2021), the coatings are sprayed on tinplate pieces, and after curing and drying, the samples are placed in an ultra-low-temperature environment of liquid nitrogen for 7 days. Six parallel cuts are made in the coating at an interval of 1mm, and another six parallel cuts are made perpendicular to the first cuts. All loose coating fragments are removed. The cutting area is visually inspected and compared with the six-level grading standard.

[0176] The results show that after immersion in liquid nitrogen for 7 days, the crosshatch adhesion test results are as shown in Figure 1 It can be seen that the cutting edge is completely smooth and there is no shedding in the grid, which meets the crosshatch adhesion 0 level, and the flexibility of the coating is good.

[0177] After 1000 hours of simulated seawater immersion, the coating surface has no obvious corrosion, and has excellent seawater corrosion resistance.

[0178] The ultra-low-temperature-resistant and seawater-corrosion-resistant topcoat and graphene epoxy zinc-rich primer in the container are both free of clumping and are in uniform liquid state after stirring. The surface drying time of the primer and topcoat is ≤5h, and the actual drying time is ≤24h.

[0179] According to GB / T 1768-2006, the abrasion resistance of the coating film is tested. The coating is sprayed on a 10cm diameter circular turntable, and the abrasion amount is less than 250mg under the condition of 750g weight and 1000r.

[0180] According to the impact resistance test, the mass of the weight is 1kG, and the impact height is 50cm. The front surface of the coating film is free of cracks and shedding.

[0181] According to GB / T 1723-93, the viscosity of the coating is tested by method 4, and the viscosity is between 60-90s.

[0182] According to GB / T 1731-2020, the flexibility of the coating film is tested. The coating film is immersed in liquid nitrogen for 7 days, and the flexibility is tested by quickly bending the coating film on a 4mm shaft rod. The results are as shown in Figure 2 and Figure 3As shown, it can be seen that the paint film deforms with its substrate without damage, and the paint film has no phenomenon of webbing, cracking and peeling, so the paint film flexibility is 4 mm.

Claims

1. A coating resistant to ultra-low temperatures and seawater corrosion, characterized in that: It consists of an ultra-low temperature resistant and seawater corrosion resistant topcoat and a graphene epoxy zinc-rich primer; the ultra-low temperature resistant and seawater corrosion resistant topcoat consists of component A and component B: By weight, component A is composed of the following raw materials: 20-50 parts of low-temperature resistant epoxy resin, 5-20 parts of fluorocarbon resin, 3-6 parts of first graphene, 1-3 parts of nano-rare earth oxide, 1-2 parts of silane coupling agent, 8-12 parts of anti-rust pigment, 10-20 parts of filler, 0.5-2 parts of first defoamer, 0.1-1 parts of first leveling agent, 0.1-1 parts of first dispersant, 0.1-1 parts of first wetting agent, 0.2-1 parts of compatibilizer, 0.5-3 parts of corrosion inhibitor, and 20-30 parts of first solvent; Component B is composed of the following raw materials: 10-15 parts of a first amine curing agent; The low-temperature resistant epoxy resin is prepared according to the following steps: Epoxy resin and polysiloxane are added to a reaction vessel and stirred at 80-100°C for 3-5 hours. Then, epoxidized hydroxyl-terminated polybutadiene is added to the reaction vessel and the mixture is stirred for another 1-2 hours to obtain a low-temperature resistant epoxy resin. The mass ratio of epoxy resin, polysiloxane, and epoxidized hydroxyl-terminated polybutadiene is 60-90:10-40:3-10.

2. The coating resistant to ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The nano-rare earth oxide is one or two of nano-cerium oxide, nano-lanthanum oxide, or nano-lanthanum-cerium oxide. The silane coupling agent is one or two of KH550, KH560, KH570 or KH792; The compatibilizer is one or two of FC-4430, KBE-403, FS-63 or GF91; the corrosion inhibitor is one or two of zinc phosphate, zinc calcium phosphate, zinc molybdate, zinc borate or lithium silicate.

3. The coating for resisting ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The filler is three, four, or five of the following: precipitated barium sulfate, iron oxide red, sericite, talc, light calcium carbonate, or kaolin. The rust-preventive pigment is mica iron oxide, zinc phosphate, aluminum tripolyphosphate, or zinc chrome yellow. The first defoamer is one or two of HY-141, DS8750, HDK H30LM, EFKA-2020 or TEGO AIREX 900; The first leveling agent is one or two of T-50, TEGO Glide 410, BYK-370 or Hyperlev F20; The first dispersant is one or two of TEGO Dispers 700, EFKA-4010 or BYK-104s; The first wetting agent is one or two of CZ-D3010, 505S or TEGO 4100; The first amine curing agent is polyamide 300#, polyamide 650#, isophorone diamine, diethylenetriamine, or diethyltoluene diamine; The first solvent is toluene, xylene, n-butyl acetate, N-75 desmoditin, or cyclohexanone.

4. The coating for resisting ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The epoxy resin is E44 or E51.

5. The coating for resisting ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The graphene epoxy zinc-rich primer is composed of component C and component D; By weight, component C is composed of the following raw materials: 15-25 parts of low-temperature resistant epoxy resin, 20-60 parts of zinc powder, 1-5 parts of second graphene, 8-15 parts of second solvent, 1-2 parts of anti-settling agent, 0.5-1 part of second dispersant, 0.5-2 parts of second defoamer, 0.1-1 part of second leveling agent, and 0.1-1 part of second wetting agent; The D component consists of 8 to 25 parts of a second amine curing agent.

6. The coating resistant to ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The second solvent is toluene, xylene, n-butyl acetate, N-75 desmoditin, or cyclohexanone; The anti-settling agent is fumed silica or organic bentonite; The second amine curing agent is polyamide 300#, polyamide 650#, isophorone diamine, diethylenetriamine or diethyltoluene diamine.

7. The coating resistant to ultra-low temperature and seawater corrosion according to claim 1, characterized in that: The second dispersant is one or two of TEGO Dispers 700, EFKA-4010, or BYK-104s; The second defoamer is one or two of HY-141, DS8750, HDK H30LM, EFKA-2020 or TEGO AIREX 900; The second leveling agent is one or two of T-50, TEGO Glide 410, BYK-370 or Hyperlev F20; The second wetting agent is one or two of CZ-D3010, 505S or TEGO 4100.

8. The method for preparing an ultra-low temperature resistant and seawater corrosion resistant coating according to claim 1, characterized in that: The ultra-low temperature resistant and seawater corrosion resistant topcoat was prepared according to the following steps: Preparation of component A: ① By weight, 3-6 parts of the first graphene, 1-3 parts of the nano rare earth oxide and 20-30 parts of the first solvent are added to an ultrasonic cleaner and ultrasonicated for 30-60 minutes to obtain a uniform nano dispersion. ② Add 20-50 parts of low-temperature resistant epoxy resin, 5-20 parts of fluorocarbon resin and 0.2-1 parts of compatibilizer to a disperser, and stir at 20-30℃ for 1-2 hours to mix evenly to obtain a mixed resin liquid; ③ Add the uniform nano-dispersion obtained in step ① to the mixed resin liquid obtained in step ②, and continue stirring for 30-45 minutes. Then add 1-2 parts of silane coupling agent, 8-12 parts of anti-rust pigment, 10-20 parts of filler, 0.5-2 parts of first defoamer, 0.1-1 parts of first leveling agent, 0.1-1 parts of first dispersant, 0.1-1 parts of first wetting agent, and 0.5-3 parts of corrosion inhibitor. Disperse in a disperser for 15-40 minutes, and then add to a grinder and grind until the fineness is less than 15 micrometers to obtain component A. Preparation of component B: 10-15 parts of a first-amine curing agent; When using, mix the obtained components A and B, and cure at 80-120℃ for 1-2 hours to create a topcoat that is resistant to ultra-low temperatures and seawater corrosion.

9. The coating for resisting ultra-low temperature and seawater corrosion according to claim 5, characterized in that: The graphene epoxy zinc-rich primer was prepared according to the following steps: Preparation of component C: By weight, add 15-25 parts of low-temperature resistant epoxy resin, 20-60 parts of zinc powder, 1-5 parts of second graphene, 8-15 parts of second solvent, 1-2 parts of anti-settling agent, 0.5-1 part of second dispersant, 0.5-2 parts of second defoamer, 0.1-1 part of second leveling agent, and 0.1-1 part of second wetting agent to a disperser and stir and disperse for 15-60 minutes. Then add it to a grinder and grind it until the fineness is less than 15 micrometers to obtain component C. Preparation of component D: 8-25 parts of second amine curing agent; When using, mix the obtained components C and D, and cure at 80-120℃ for 1-2 hours to form a graphene epoxy zinc-rich primer.

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