A kind of nano liquid coating for long-term anticorrosion of ship and its preparation and application

Abstract

The application discloses a kind of ship long-acting anticorrosion nanometer liquid paint and its preparation and application, it is related to ship anticorrosive paint technical field.The ship long-acting anticorrosion nanometer liquid paint of the application includes component A and component B, the mass ratio of component A and component B is 4:1;Component A at least includes the following mass parts raw materials: graphene-epoxy hybrid liquid 60-80 parts;Modified nanometer sheet hydroxyapatite 2-5 parts;Inhibitor loaded nanometer cerium dioxide 3-6 parts;Cosolvent 5-10 parts;Auxiliary agent 1-3 parts;Component B at least includes the following mass parts raw materials: polyether amine curing agent 20-30 parts;Latent catalyst 0.5-1 part.The ship long-acting anticorrosion nanometer liquid paint prepared by the application forms anticorrosive coating with strong adhesion, excellent protection performance, outstanding salt fog resistance, and has efficient self-repairing ability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine anticorrosive coating, in particular to a kind of marine long-acting anticorrosive nano liquid coating and its preparation and application. BACKGROUND

[0002] Marine structures and ships are in a harsh environment of dry-wet alternation, salt spray and ultraviolet radiation all the year round, and the corrosion of their metals is much more serious than that of land steels. Corrosion not only leads to the decline or rupture of mechanical properties of steels, but also causes marine accidents. At present, the most common method is to isolate the ship surface from corrosive medium by using anticorrosive coating to play a protective role.

[0003] Traditional antifouling coatings contain toxic fillers to inhibit the attachment of marine fouling organisms, but the toxic fillers have great harm to the environment, so it is necessary to develop new practical antifouling coatings to replace toxic antifouling coatings. Studies have shown that graphene has certain antibacterial properties, and the structure of graphene can provide physical corrosion protection, so adding graphene or functionalized graphene to the coating can achieve a coating with both antifouling and corrosion protection functions.

[0004] In the technical field of marine anticorrosive coating, traditional coatings have many technical bottlenecks and cannot meet the comprehensive needs of modern ships for long-acting anticorrosion, convenient construction and environmental performance. Traditional epoxy coatings require heat curing above 80℃, which is difficult to achieve uniform heating on site for large ship components, resulting in incomplete curing; direct addition of graphene can easily cause π-π stacking, and the coating layer can form a conductive path (resistivity <10 6 Ω·cm), which accelerates the electrochemical corrosion of the metal substrate; the existing self-drying coatings (such as alkyd resins) have a salt spray resistance <1000h (ISO 7253), which cannot meet the requirements of IMO “Performance Standard for Protective Coatings for Cargo Oil Tanks” PSPC.

[0005] In addition, marine anticorrosive coatings also face three major technical contradictions: first, the contradiction between the long-acting anticorrosion demand of graphene and its easy promotion of galvanic corrosion, how to achieve uniform dispersion of graphene in the coating and avoid the formation of conductive paths is the key to exert its anticorrosion effect; second, the contradiction between the convenience of self-drying coating construction and the super-long anticorrosion performance, the existing self-drying coatings often sacrifice the anticorrosion durability in pursuit of construction speed, and it is difficult to balance both; third, the contradiction between the low VOC environmental protection requirement and the high cross-linking density curing demand, reducing the VOC content often leads to insufficient cross-linking degree of the coating, affecting the physical and mechanical properties and anticorrosion effect of the coating. Therefore, it is of great significance to develop a marine anticorrosive coating with long-acting anticorrosion, rapid self-drying, low VOC environmental protection characteristics, and to solve the above technical contradictions. SUMMARY

[0006] The application aims to provide a nano liquid coating for long-term corrosion prevention of a ship and a preparation and application thereof, and solve the following technical problems:

[0007] The existing nano liquid coating has defects such as insufficient corrosion resistance, low self-repairing efficiency and easy falling off when used for ship corrosion prevention.

[0008] The application can achieve the purpose by the following technical scheme.

[0009] A nano liquid coating for long-term corrosion prevention of a ship comprises component A and component B, and the mass ratio of the component A to the component B is 4:1.

[0010] The component A comprises at least the following raw materials in parts by mass:

[0011] 60-80 parts of graphene-epoxy hybrid liquid, 2-5 parts of modified nanosheet hydroxyapatite, 3-6 parts of inhibitor-loaded nanometer cerium dioxide, 5-10 parts of cosolvent and 1-3 parts of additive;

[0012] The component B comprises at least the following raw materials in parts by mass:

[0013] 20-30 parts of polyether amine curing agent and 0.5-1 part of latent catalyst.

[0014] As a further scheme of the application, the preparation method of the graphene-epoxy hybrid liquid comprises the following steps:

[0015] The carboxylated graphene is dispersed in gamma-hydroxybutyric lactone and ultrasonically treated, then the prepolymer of epoxy resin and gamma-glycidyl ether oxypropyl trimethoxysilane and a catalyst are added for reaction to obtain the graphene-epoxy hybrid liquid.

[0016] As a further scheme of the application, the viscosity of the graphene-epoxy hybrid liquid at 25 DEG C is 800-1200 cP, the mass ratio of the carboxylated graphene to the prepolymer is 0.3-1.2:100, the hydroxyl value of the epoxy resin is 120-150 mg KOH / g, and the C / O atomic ratio in the carboxylated graphene is >8:1.

[0017] As a further scheme of the application, the preparation method of the inhibitor-loaded nanometer cerium dioxide comprises at least the following steps:

[0018] Cerium nitrate hexahydrate and urea are added to deionized water, and after reaction, centrifugation, washing, dispersion in deionized water, addition of sodium hydroxide, hydrothermal reaction, washing and drying, calcination is performed to obtain cerium dioxide nanotubes;

[0019] The cerium dioxide nanotubes and 2-mercaptobenzothiazole are added to acetone, ultrasonically dispersed, vacuum is applied, and after washing and drying, the inhibitor-loaded nanometer cerium dioxide is obtained.

[0020] As a further aspect of the present invention: the diameter of the cerium dioxide nanotube is 20-40 nm, and the mass ratio of the cerium dioxide nanotube to the 2-mercaptobenzothiazole is 1:0.5-1.5.

[0021] As a further aspect of the present invention, the preparation method of the modified nanosheet hydroxyapatite includes the following steps:

[0022] Nanosheet hydroxyapatite was ultrasonically dispersed in Tris buffer solution, dopamine was added to react, and after centrifugation, washing and drying, polydopamine-modified nanosheet hydroxyapatite was obtained.

[0023] The polydopamine-modified nanosheet hydroxyapatite was dispersed in deionized water, zinc nitrate hexahydrate was added and stirred, and after centrifugation, washing and drying, modified nanosheet hydroxyapatite was obtained.

[0024] As a further aspect of the present invention: the aspect ratio of the nanosheet hydroxyapatite is 40-60:1, the mass ratio of the nanosheet hydroxyapatite to the dopamine is 1:0.8-1, and the mass ratio of the polydopamine-modified nanosheet hydroxyapatite to the zinc nitrate hexahydrate is 3-8:1.

[0025] As a further aspect of the present invention: the co-solvent is a compound solvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:1; the auxiliary agent includes at least one of defoamer or leveling agent; the polyetheramine curing agent includes at least T-403; and the latent catalyst includes at least 2-ethyl-4-methylimidazolium copper complex.

[0026] A method for preparing a long-lasting anti-corrosion nano-liquid coating for ships as described in any one of the above methods includes at least the following preparation steps:

[0027] The graphene-epoxy hybrid liquid, nano-sheet hydroxyapatite, and corrosion inhibitor-loaded nano-cerium dioxide were dispersed by a three-roll mill, and a co-solvent and additives were added to obtain the A-component coating.

[0028] A polyetheramine curing agent and a latent catalyst are mixed to obtain a component B coating.

[0029] The A-component coating and the B-component coating are mixed and cured to obtain a nano-liquid coating for long-lasting corrosion protection of ships.

[0030] An application of a nano-liquid coating for long-term corrosion protection of ships as described in any of the above claims, wherein the nano-liquid coating is applied for long-term corrosion protection of ships.

[0031] The beneficial effects of this invention are:

[0032] The nano-liquid coating for long-lasting corrosion protection of ships prepared in this invention comprises component A and component B. Component A includes a graphene-epoxy hybrid liquid, an inorganic nano-dispersion liquid, and a co-solvent, while component B includes a polyetheramine curing agent and a latent catalyst. In this invention, the combination of epoxy resin substrate, curing agent, and catalyst allows the polyetheramine to react with epoxy groups to form a preliminary cross-linked network with a gel rate >80%. Upon contact with seawater, copper ions in the latent catalyst catalyze secondary cross-linking, forming coordination bonds with hydroxyapatite to further increase the cross-linking density. This approach balances rapid setting and long-term stability, achieving room-temperature step-curing. At 25°C, the surface drying time is only 2 hours, eliminating the need for high-temperature baking and solving the problem of difficult on-site heating of large ship components. The graphene-epoxy hybrid liquid prepared in this invention, through the bridging effect of a silane coupling agent, covalently grafts carboxylated graphene onto the epoxy resin chain, fundamentally avoiding graphene aggregation and the resulting galvanic corrosion risk, thus fully utilizing its excellent shielding performance. Meanwhile, the compounded co-solvent system used in this invention ensures that the VOC content of the coating is below 250g / L, which complies with strict environmental regulations. The formula has good thixotropic properties and can be coated up to 150μm in one go without sagging, reducing the number of applications and improving efficiency. It is suitable for coating requirements of complex parts of ships such as waterline areas, decks, and cabins.

[0033] The inorganic nano-dispersion in component A of this invention includes modified nanosheet hydroxyapatite and corrosion inhibitor-supported nano-cerium dioxide, forming a multi-layered anti-corrosion mechanism with the graphene-epoxy hybrid solution. The modified nanosheet hydroxyapatite is polydopamine-modified nanosheet hydroxyapatite that chelates zinc ions. The covalently grafted graphene in the nanosheet hydroxyapatite and graphene-epoxy hybrid solution forms an ultra-long penetration path for corrosive media in the coating. Furthermore, the polydopamine-modified nanosheet hydroxyapatite exhibits strong adsorption of corrosive chloride ions, consuming corrosion factors at the source. After coating damage, some zinc ions react with OH- generated on the cathode. - A Zn(OH)₂ passivation film is formed, while a portion of it undergoes coordination crosslinking with the catechol groups in polydopamine at the damaged interface. Both mechanisms jointly promote the re-adhesion and bonding of the damaged interface. The corrosion inhibitor-loaded nano-cerium dioxide consists of 2-mercaptobenzothiazole-loaded cerium dioxide nanotubes. When corrosion occurs, the local pH increases, triggering the precise release of the 2-mercaptobenzothiazole corrosion inhibitor from the cerium dioxide nanotubes, forming a passivation film on the metal surface and preventing corrosion propagation. The nano-cerium dioxide itself also possesses redox catalytic capabilities, consuming some corrosive active oxygen species and improving the coating's aging resistance. This invention provides a multi-layered anti-corrosion mechanism that significantly improves the utilization efficiency and protective durability of the corrosion inhibitor. The resulting coating exhibits high crosslinking density and good compactness, with a neutral salt spray test time exceeding 8000 hours. Detailed Implementation

[0034] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: The preparation method of corrosion inhibitor-supported nano-cerium dioxide includes the following steps:

[0036] 3.4 g of cerium nitrate hexahydrate and 7.2 g of urea were dissolved in a 250 mL round-bottom flask. 160 mL of deionized water was added and mixed thoroughly. The mixture was then vigorously stirred and refluxed at 80 °C for 24 h. After centrifugation, the product was washed with deionized water and dispersed in 40 mL of deionized water. Sodium hydroxide was added to adjust the pH to 10.5. After stirring for 30 min, the mixture was transferred to a 100 mL reaction vessel and subjected to a hydrothermal reaction at 120 °C for 24 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The precipitate was washed with deionized water and anhydrous ethanol by centrifugation. Finally, the precipitate was dried under vacuum at 60 °C for 24 h and calcined at 550 °C for 2 h to obtain cerium dioxide nanotubes.

[0037] The cerium dioxide nanotubes were dried in an oven at 80°C for 12 hours. 2 g of the dried cerium dioxide nanotubes and 2 g of 2-mercaptobenzothiazole were added to 1000 mL of acetone and ultrasonically dispersed evenly. The mixed solution was then connected to a vacuum system, and 2-mercaptobenzothiazole was drawn into the cerium dioxide nanotubes using vacuum. This process was repeated three times. After washing, the nanotubes were dried at 60°C for 24 hours to obtain corrosion inhibitor-loaded nano-cerium dioxide.

[0038] Example 2: The preparation method of modified nanosheet hydroxyapatite includes the following steps:

[0039] 2g of nanosheet hydroxyapatite with an aspect ratio of 50:1 was added to 800mL of Tris buffer solution (pH=8.5) and ultrasonically dispersed for 20min, then stirred for 1h. 1.6g of dopamine was then added and stirred at room temperature for 24h. After the reaction was completed, the mixture was centrifuged at 8000rpm / min, washed three times with ethanol and deionized water, and dried in a vacuum oven for 24h to obtain polydopamine-modified nanosheet hydroxyapatite.

[0040] 2g of the above-mentioned polydopamine-modified nanosheet hydroxyapatite was dispersed in 1000ml of deionized water and ultrasonically dispersed for 30min. 0.4g of zinc nitrate hexahydrate was added and stirred continuously for 2h. After the reaction was completed, the mixture was centrifuged at 8000rpm / min and then washed three times with ethanol and deionized water. The mixture was then dried in a vacuum oven for 24h to obtain modified nanosheet hydroxyapatite with a zinc ion loading of about 4wt%.

[0041] Example 3: The preparation method of graphene-epoxy hybrid liquid includes the following steps:

[0042] 70g of epoxy resin E-20 and 30g of γ-glycidyl etheroxypropyltrimethoxysilane were added to a three-necked flask, and then 0.5% of the total mass of the two catalysts, dibutyltin dilaurate, were added. The mixture was stirred at 95°C for 3 hours, and the reaction byproducts were removed under vacuum to obtain the prepolymer.

[0043] 0.6 g of carboxylated graphene with a C / O atomic ratio of 10:1 was dispersed in γ-hydroxybutyrate lactone and sonicated at 40 kHz for 1 h. Then, the above prepolymer and catalyst Sn(Oct)2 were added and reacted at 110 °C for 3 h to obtain a graphene-epoxy hybrid liquid with a viscosity of 900 cP (25 °C).

[0044] Example 4: The preparation method of graphene-epoxy hybrid liquid includes the following steps:

[0045] 70g of epoxy resin E-20 and 30g of γ-glycidyl etheroxypropyltrimethoxysilane were added to a three-necked flask, and then 0.5% of the total mass of the two catalysts, dibutyltin dilaurate, were added. The mixture was stirred at 95°C for 3 hours, and the reaction byproducts were removed under vacuum to obtain the prepolymer.

[0046] 1g of carboxylated graphene with a C / O atomic ratio of 10:1 was dispersed in γ-hydroxybutyrate lactone and ultrasonicated at 40kHz for 1h. Then, the above prepolymer and catalyst Sn(Oct)2 were added and reacted at 110℃ for 3h to obtain a graphene-epoxy hybrid liquid with a viscosity of 1000cP (25℃).

[0047] Example 5: A method for preparing a long-lasting anti-corrosion nano-liquid coating for ships includes the following steps:

[0048] 70 parts by weight of the graphene-epoxy hybrid liquid prepared in Example 3, 3.5 parts by weight of the modified nano-sheet hydroxyapatite prepared in Example 2, and 4.5 parts by weight of the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 were dispersed to a fineness of ≤15μm using a three-roll mill (5μm gap). Then, 8 parts by weight of a cosolvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:1, 1 part by weight of defoamer BYK-1790, and 1 part by weight of leveling agent TEGO Glide 410 were added to obtain component A coating.

[0049] 25 parts by weight of polyetheramine curing agent T-403 with an amine value of 245 mg KOH / g and 0.8 parts of 2-ethyl-4-methylimidazolium copper complex were mechanically stirred and mixed evenly to obtain component B coating.

[0050] The above-mentioned component A coating and component B coating are mixed at a mass ratio of 4:1 and cured for 30 minutes to obtain a nano liquid coating for long-term anti-corrosion of ships.

[0051] Example 6: A method for preparing a long-lasting anti-corrosion nano-liquid coating for ships includes the following steps:

[0052] 70 parts by weight of the graphene-epoxy hybrid liquid prepared in Example 4, 3.5 parts by weight of the modified nano-sheet hydroxyapatite prepared in Example 2, and 4.5 parts by weight of the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 were dispersed to a fineness of ≤15μm using a three-roll mill (5μm gap). Then, 8 parts by weight of a cosolvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:1, 1 part by weight of defoamer BYK-1790, and 1 part by weight of leveling agent TEGO Glide 410 were added to obtain component A coating.

[0053] 25 parts by weight of polyetheramine curing agent T-403 with an amine value of 245 mg KOH / g and 0.8 parts of 2-ethyl-4-methylimidazolium copper complex were mechanically stirred and mixed evenly to obtain component B coating.

[0054] The above-mentioned component A coating and component B coating are mixed at a mass ratio of 4:1 and cured for 30 minutes to obtain a nano liquid coating for long-term anti-corrosion of ships.

[0055] Example 7 A method for preparing a long-lasting anti-corrosion nano-liquid coating for ships includes the following steps:

[0056] 65 parts by mass of the graphene-epoxy hybrid liquid prepared in Example 3, 5 parts by mass of the modified nanosheet hydroxyapatite prepared in Example 2, and 5 parts by mass of the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 were dispersed to a fineness of ≤15μm using a three-roll mill (5μm gap). Then, 8 parts by mass of a cosolvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:1, 1 part by mass of defoamer BYK-1790, and 1 part by mass of leveling agent TEGO Glide 410 were added to obtain component A coating.

[0057] 25 parts by weight of polyetheramine curing agent T-403 with an amine value of 245 mg KOH / g and 0.8 parts of 2-ethyl-4-methylimidazolium copper complex were mechanically stirred and mixed evenly to obtain component B coating.

[0058] The above-mentioned component A coating and component B coating are mixed at a mass ratio of 4:1 and cured for 30 minutes to obtain a nano liquid coating for long-term anti-corrosion of ships.

[0059] Example 8 A method for preparing a long-lasting anti-corrosion nano-liquid coating for ships includes the following steps:

[0060] 65 parts by mass of the graphene-epoxy hybrid liquid prepared in Example 4, 5 parts by mass of the modified nano-sheet hydroxyapatite prepared in Example 2, and 5 parts by mass of the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 were dispersed to a fineness of ≤15μm using a three-roll mill (5μm gap). Then, 8 parts by mass of a cosolvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:1, 1 part by mass of defoamer BYK-1790, and 1 part by mass of leveling agent TEGO Glide 410 were added to obtain component A coating.

[0061] 25 parts by weight of polyetheramine curing agent T-403 with an amine value of 245 mg KOH / g and 0.8 parts of 2-ethyl-4-methylimidazolium copper complex were mechanically stirred and mixed evenly to obtain component B coating.

[0062] The above-mentioned component A coating and component B coating are mixed at a mass ratio of 4:1 and cured for 30 minutes to obtain a nano liquid coating for long-term anti-corrosion of ships.

[0063] Compared with Example 5, Comparative Example 1 only replaced the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 with cerium dioxide nanowires with a diameter of 20 nm. The other components and preparation methods were completely the same as those in Example 5.

[0064] Compared with Example 5, Comparative Example 2 only replaced the modified nanosheet hydroxyapatite prepared in Example 2 with nanosheet hydroxyapatite in the same mass as in Example 5. The other components and preparation methods were completely the same as in Example 5.

[0065] Compared with Example 5, Comparative Example 3 only replaced the graphene-epoxy hybrid liquid prepared in Example 3 with the prepolymer prepared in Example 3 by the same mass. The other components and preparation methods were completely the same as those in Example 5.

[0066] Compared with Example 5, Comparative Example 4 replaced the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 with a physical mixture of cerium dioxide nanowires with a diameter of 20 nm and 2-mercaptobenzothiazole, and replaced the modified nanosheet hydroxyapatite prepared in Example 2 with a physical mixture of nanosheet hydroxyapatite and zinc nitrate hexahydrate. The remaining components and preparation methods were completely consistent with those of Example 5.

[0067] Compared with Example 5, Comparative Example 5 replaced the corrosion inhibitor-loaded nano-cerium dioxide prepared in Example 1 with cerium dioxide nanowires with a diameter of 20 nm, replaced the modified nanosheet hydroxyapatite prepared in Example 2 with nanosheet hydroxyapatite, and replaced the graphene-epoxy hybrid liquid prepared in Example 3 with the prepolymer prepared in Example 3. The remaining components and preparation methods were completely consistent with Example 5.

[0068] Performance testing

[0069] The nano-liquid coatings for long-lasting anti-corrosion of ships obtained in Examples 5-8 and Comparative Examples 1-5 were applied to Q235 steel plates sandblasted to Sa 2.5 grade, with a dry film thickness controlled at 150±10μm. Curing was performed at 25℃ and 50%RH, with a surface drying time of 2 hours. The VOC content was below 250 g / L, meeting environmental protection requirements. Performance testing was then conducted on the formed anti-corrosion coating.

[0070] Adhesion Testing: Coating adhesion testing plays a crucial role in evaluating the anti-corrosion performance of coatings. It is essential for ensuring the anti-corrosion performance, durability, and quality control of coatings, directly affecting their protective effect and service life. Higher bonding strength between the coating and the substrate is more beneficial for improving the coating's anti-corrosion performance. To determine the coating adhesion, a Positest ATA-20 pull-out fully automatic adhesion tester was used. First, the sample surface and test spindle were pre-ground to improve adhesion. Then, a special adhesive was used to firmly bond the coating sample to the test spindle. After the adhesive had completely cured, the adhesion was measured according to the standard testing procedure. To ensure data reliability, three parallel samples were set up for each experiment, and each sample was tested three times. Finally, the average of all test results was taken as the adhesion value of the coating; the test results are shown in Table 1.

[0071] Electrochemical testing: The electrochemical impedance of the coating samples at different immersion times was measured using an electrochemical workstation. The workstation used in this experiment was a Shanghai Chenhua CH1660. A 3.5wt% NaCl solution was selected as the medium, and the medium was changed periodically. The testing frequency range was 10... -2 -10 5 The Hz disturbance voltage amplitude was 20mV. The low-frequency impedance modulus |Z| was recorded after 30 days of immersion, reaching 0.01Hz. The test results are shown in Table 1.

[0072] Neutral salt spray test: A Q-Fog cyclic salt spray corrosion test chamber was used, and a 5wt% NaCl solution was prepared periodically. Following the standard GB / T 31588.1-2015 "Determination of Resistance to Cyclic Corrosion Environments of Paints and Varnishes", a scratch was made through the coating, penetrating the substrate. The scratch width was not less than 0.2 mm, and the distance from the edges was more than 20 mm. The edges of the metal substrate were sealed with a mixture of rosin and paraffin to prevent corrosive media from corroding the coating from the edges of the metal substrate, which could cause experimental errors. After the salt spray test began, the surface condition of the coating was observed periodically. The test results are shown in Table 1.

[0073] Self-healing rate: The scratch repair electrochemical test was used. A scratch with a width of 0.2 mm was prepared on the coating surface and immersed in 3.5 wt% NaCl solution for 72 h. The ratio of charge transfer resistance (Rct) before and after repair was calculated by electrochemical impedance spectroscopy (EIS), that is, self-healing rate = (Rct after repair / Rct before repair) × 100%; the test results are shown in Table 1.

[0074] Table 1: Statistical Table of Anti-corrosion Coating Performance Test Data for Examples 5-8 and Comparative Examples 1-5

[0075]

[0076] As shown in Table 1, the nano-liquid coating for long-lasting corrosion protection of ships prepared by this invention, when applied to the surface of steel plates, results in a coating with strong adhesion, excellent protective performance, outstanding salt spray resistance, and highly efficient self-healing ability. In Comparative Example 1, the nano-cerium dioxide added was not loaded with a corrosion inhibitor, leading to a significant decrease in the self-healing rate and salt spray performance of the resulting coating. In Comparative Example 2, the nano-flaky hydroxyapatite added was not modified, resulting in a shortened salt spray resistance time for the resulting coating. In Comparative Example 3, the epoxy hybrid liquid lacked graphene grafting, resulting in a significant decrease in all aspects of the performance of the resulting coating. In Comparative Example 4, the nanomaterials were only physically blended, resulting in a coating with performance lower than that of the examples. In Comparative Example 5, no multiple anti-corrosion mechanisms were formed, resulting in the worst performance of the resulting coating.

[0077] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0078] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A nano-liquid coating for long-lasting corrosion protection of ships, characterized in that, It includes component A and component B, wherein the mass ratio of component A to component B is 4:1; Component A comprises at least the following parts by weight of raw materials: Graphene-epoxy hybrid solution 60-80 parts; modified nano-sheet hydroxyapatite 2-5 parts; corrosion inhibitor supported on nano-cerium dioxide 3-6 parts; co-solvent 5-10 parts; additives 1-3 parts; Component B comprises at least the following parts by weight of raw materials: 20-30 parts polyetheramine curing agent; 0.5-1 part latent catalyst; The preparation method of the graphene-epoxy hybrid liquid includes the following steps: Carboxylated graphene was dispersed in γ-hydroxybutyrate lactone and ultrasonically treated. Then, epoxy resin and γ-glycidyl etheroxypropyltrimethoxysilane prepolymer and catalyst were added and reacted to obtain graphene-epoxy hybrid liquid. The method for preparing the corrosion inhibitor loaded with nano-cerium dioxide includes at least the following steps: Cerium nitrate hexahydrate and urea were added to deionized water. After the reaction, the mixture was centrifuged, washed, and then dispersed in deionized water. Sodium hydroxide was added, and after hydrothermal reaction, the mixture was washed, dried, and calcined to obtain cerium dioxide nanotubes. The cerium dioxide nanotubes and 2-mercaptobenzothiazole were added to acetone, ultrasonically dispersed, and then subjected to vacuum conditions. After washing and drying, corrosion inhibitor-loaded nano-cerium dioxide was obtained. The preparation method of the modified nanosheet hydroxyapatite includes the following steps: Nanosheet hydroxyapatite was ultrasonically dispersed in Tris buffer solution, dopamine was added to react, and after centrifugation, washing and drying, polydopamine-modified nanosheet hydroxyapatite was obtained. The polydopamine-modified nanosheet hydroxyapatite was dispersed in deionized water, zinc nitrate hexahydrate was added and stirred, and after centrifugation, washing and drying, modified nanosheet hydroxyapatite was obtained.

2. The nano-liquid coating for long-lasting corrosion protection of ships according to claim 1, characterized in that, The graphene-epoxy hybrid liquid has a viscosity of 800-1200 cP at 25°C, the mass ratio of the carboxylated graphene to the prepolymer is 0.3-1.2:100, the hydroxyl value of the epoxy resin is 120-150 mg KOH / g, and the C / O atomic ratio in the carboxylated graphene is >8:

1.

3. The nano-liquid coating for long-lasting corrosion protection of ships according to claim 1, characterized in that, The cerium dioxide nanotubes have a diameter of 20-40 nm, and the mass ratio of the cerium dioxide nanotubes to the 2-mercaptobenzothiazole is 1:0.5-1.

5.

4. The nano-liquid coating for long-lasting anti-corrosion of ships according to claim 1, characterized in that, The aspect ratio of the nanosheet hydroxyapatite is 40-60:1, the mass ratio of the nanosheet hydroxyapatite to the dopamine is 1:0.8-1, and the mass ratio of the polydopamine-modified nanosheet hydroxyapatite to the zinc nitrate hexahydrate is 3-8:

1.

5. The nano-liquid coating for long-term corrosion protection of ships according to claim 1, characterized in that, The co-solvent is a compound solvent composed of propylene glycol methyl ether acetate and γ-hydroxybutyrate lactone in a mass ratio of 3:

1. The auxiliary agent includes at least one of defoamer or leveling agent. The polyetheramine curing agent includes at least T-403. The latent catalyst includes at least 2-ethyl-4-methylimidazolium copper complex.

6. A method for preparing a nano-liquid coating for long-lasting corrosion protection of ships as described in any one of claims 1-5, characterized in that, It includes at least the following preparation steps: The graphene-epoxy hybrid liquid, nano-sheet hydroxyapatite, and corrosion inhibitor-loaded nano-cerium dioxide were dispersed by a three-roll mill, and a co-solvent and additives were added to obtain the A-component coating. A polyetheramine curing agent and a latent catalyst are mixed to obtain a component B coating. The A-component coating and the B-component coating are mixed and cured to obtain a nano-liquid coating for long-lasting corrosion protection of ships.

7. The application of a nano-liquid coating for long-term corrosion protection of ships as described in any one of claims 1-5, characterized in that, The nano-liquid coating is used for long-term corrosion protection of ships.

Images